PCB plating

2000 China's PCB production value of $ 3.635 billion , accounting for 8.7 % of global PCB output value , ranking fourth in the world . In China 's PCB output value , accounting for 83.5 percent of Guangdong . Therefore , the Guangdong region PCB plating is a great industry .

Electroplating technology introduction

One . Plating process category:

Acid bright copper plating, electroless nickel / gold , tin plating

Two . Process:

Pickling --- full board plating copper --- pattern transfer --- acidic degreasing --- two countercurrent rinsing --- microetch --- two countercurrent rinsing --- pickle --- tin - - two countercurrent rinsing --- countercurrent rinsing pickling --- --- --- two counterflow pattern plating copper nickel plating rinse --- washing --- Baptist --- two gilded citrate --- --- recycling --- 2-3 grade pure water --- drying

Three . Process Description :

( A ) pickle

① role and purpose :
Remove the plate surface oxides , activated the board , the general concentration of 5% , and some remained at around 10% , mainly to prevent the moisture content of sulfuric acid into the bath instability ;

② acid leaching time not too long , to prevent oxidation of the board ; in use for some time , the acid should appear cloudy or timely replacement of copper content is too high , preventing pollution plated copper cylinder and the plate surface ;

③ here should be used C.P grade sulfuric acid ;

( B) the full board plating copper : also known as a copper, board , Panel-plating

① role and purpose : to protect just a thin electroless copper deposition , electroless copper to prevent oxidation after acid etching away by plating will add to it to a certain extent after

② full board copper plating process parameters : bath main ingredients are copper sulfate and sulfuric acid using high- low copper formulations , plating board to ensure uniformity and thickness distribution of the deep dark hole plating capability ; sulfuric acid content and more 180 g / l, more than those of 240 g / l ; copper content is generally 75 g / l , and the other bath traces of chloride ions added as an auxiliary optical brightener agents work together and copper luster effect ; copper Add the amount of light agent or open cylinder volume is generally 3-5ml / L, adding copper matting agent is generally in accordance with a thousand ways to supplement or hours based on the actual production of board effectiveness ; entire board plating current calculation generally 2 amps / sq decimeter by multiplying the board electroplating area for the whole board to that board long plate width dm × dm × 2 × 2A / DM2; Tong Gang temperature was maintained at room temperature , generally at temperatures not exceeding 32 degrees, and more control at 22 degrees , so in the summer due to high temperatures , Tong Gang recommended to install the cooling temperature control system ;

③ process maintenance :
According to the daily to replenish a thousand hours of copper agent, supplemented by 100-150ml/KAH added ; checking the filter pump is working properly , without leakage phenomenon ; every 2-3 hours with clean wet rag cathode conductive rod scrub clean ; week to regularly analyze Tong Gang copper sulfate ( 1 times / week ) , sulfuric acid ( 1 times / week ) , chloride ( 2 times / week ) content , and through the Hall cell test agent to adjust light levels , and replenish related materials ; week to clean the anode conductive rods, electrical connectors at both ends of the tank , replenish titanium anode basket ball, with a low current 0 2 0 5ASD electrolysis 6 8 hours ; should be checked every month titanium anode basket bags without damage, the damage should be replaced ; titanium anode basket and check whether the accumulation of bottom anode mud, if any should be clean ; continuous filtration with carbon core 6 8 hours , while low current electrolysis impurity ; every six months based on specific decisions about whether pollution in big bath treatment ( activated carbon powder ) ; every two weeks to replace the filter pump filter ;

④ large Handler : A. Remove the anode , the anode poured cleaning anode surface anodic film , and then placed in the packaging of copper anode barrel, with micro- roughened copper corrosion agent angle to the surface to a uniform pink , red dry washing after loading the titanium basket , square into the acid bath spare B. titanium anode baskets and anode bags soaked in lye into 10% 6 - 8 hours , washed red dry , then 5% dilute sulfuric acid soaking , washing dry red after standby ; C. standby tank to transfer to the bath , was added 1-3ml / 30% hydrogen peroxide of L , start heating until the temperature is about 65 degrees to the air added with stirring , stirred for 2-4 hours heat the air ; D Turn off the air stirred by three 5 g / l of active carbon will slowly dissolve into the bath , until thoroughly dissolved , stirring open air , so incubated for 2-4 hours ; E. Turn off the air mixing , heating, let activated carbon powder slowly settling to the bottom ; F. until the temperature dropped about 40 degrees , with 10um filtered bath of PP filter plus filter aid powder to clean the work tank , open air mixing, into the anode , hanging into the electrolytic plates , according to 0 2-0 5ASD current density and low current electrolysis 6 8 hours , G. through laboratory analysis , adjusting tank of sulfuric acid , copper sulfate, chloride ion content to within the normal operating range ; according to Hall groove the results complement light dose ; H. electrolytic plate board surface to be evenly color , you can stop electrolysis, then press 1-1 5ASD current density electrolysis raw film treatment for 1-2 hours , until a uniform layer on the anode generates dense . good adhesion of the film to black phosphorus ; I. plated OK to try ;

⑤ copper balls contained in the anode 3 - 6 % of phosphorus , the main purpose is to reduce the efficiency of the anodic dissolution to reduce the generation of copper ;

⑥ supplementary medicines, such as adding a large amount of copper sulfate, sulfuric acid ; should look after adding low-current electrolysis ; additional sulfuric acid should pay attention to safety , a large amount of additional time (10 liters ) should slow up several times plus ; otherwise it will create the bath temperature , light stabilizers accelerate decomposition , contamination bath ;

Special attention should be ⑦ additional chloride ions , particularly low because the chloride ion content (30-90ppm), be sure to use when adding additional cylinder or measuring cup after weighing accuracy ; 1ml hydrochloric acid, chlorine ions about 385ppm.

⑧ drugs add formula:
Copper ( unit: kg ) = (75-X) × tank volume ( L ) / 1000
Sulfuric acid ( Unit : L ) = (10%-X) g / L × tank volume ( liters )
Or ( Unit: L ) = (180-X) g / L × tank volume ( liters ) / 1840
Hydrochloric acid ( unit : ml) = (60-X) ppm × tank volume ( liters ) / 385

(C ) acidic degreasing

① purpose and effect : to remove the surface oxide copper lines , ink plastic film over glue , binding force guarantee a copper or nickel plated copper and graphics between

② Remember acidic degreaser used here , why not use alkaline degreasers and degreasing effect of alkaline degreasers better than the acidic degreaser ? Mainly because the graphics are not alkali ink will damage the graphic line , it can only be used before the pattern plating acidic degreaser .

③ only control the production concentration and time to degreasers , degreasers concentration of about 10% , the time to ensure that in six minutes , a little longer will not have an adverse effect ; bath replacement is in accordance with the use of 15 square meters / liter Work liquid supplement add 100 square meters according to 0 5 0 8L;

(D ) microetch :

① purpose and effect : clean copper surface roughening line , make sure the graphics plating adhesion between copper and a copper

② micro- corrosion agent to use more sodium persulfate , coarsening rate steady uniform washing is good, the general control over the sodium concentration of 60 g / l or so , the time control in about 20 seconds , pharmaceuticals add 3-4 kg at 100 meters ; copper content control at 20 g / liter ; other maintenance are changing with heavy copper cylinder microetching .

(E ) pickling

① role and purpose :
Remove the plate surface oxides , activated the board , the general concentration of 5% , and some remained at around 10% , mainly to prevent the moisture content of sulfuric acid into the bath instability ;

② acid leaching time not too long , to prevent oxidation of the board ; in use for some time , the acid should appear cloudy or timely replacement of copper content is too high , preventing pollution plated copper cylinder and the plate surface ;

③ here should be used C.P grade sulfuric acid ; ( Six ) Graphic plated copper : also known as secondary copper, copper wiring

① purpose and effect : to meet the nominal current load line after each line and the need to reach a certain hole copper thickness of copper , copper wiring purposes timely hole copper and copper lines thickened to a certain thickness ;

② other items are plated with full board( Seven ) tin plating

① purpose and effect : The main purpose of pure tin plating graphics using pure tin metal purely as a resist layer, the protection circuit etching ;

② Main bath of sulfuric acid , stannous sulfate, and additives ; controlling the content of stannous sulfate 35 g / l , sulfuric acid of about 10% in controls ; tin additive is generally added according to a thousand hours , or a method based on the actual complement board production results ; tin plating current calculation generally 1 5 a / dm multiplied by the area be plated board ; tin cylinder temperature was maintained at room temperature , generally a temperature not exceeding 30 degrees, 22 degrees more than the control , and therefore due to high summer temperatures , tin cylinder recommended to install the cooling temperature control system ;

③ process maintenance : daily to replenish tin additive agent according to a thousand hours ; check the filter if the pump is working properly, without leakage phenomenon ; every 2-3 hours with clean wet rag and cleaned cathode conductive rod ; each week to regularly analyze tin cylinder stannous sulfate ( 1 times / week ) , sulfuric acid ( 1 times / week ) , and through the Hall cell test to adjust tin additive content and replenish related materials ; conductive anode rod should be cleaned weekly , electrical connectors at both ends of the tank ; week with low current 0 2-0 5ASD electrolysis 6-8 hours ; . anode bags should be checked monthly for damage , damage should be replaced ; and check the bottom of the anode bags are piled there anode mud, if any should be clean ; monthly continuous filtration with carbon core 6-8 hours , while low current electrolysis impurity ; every six months or so to determine whether the specific needs of large treatment ( activated carbon powder ) in accordance with the bath pollution status ; every two week to replace the filter pump filter ;

④ large Handler : A. Remove the anode , remove the anode bag , cleaning brush with copper anode surface , red dry after washing , into the anode bag , into the acid tank spare B. 10% of the anode bag into lye soak for 6-8 hrs, washed red dry, then soaked in 5% sulfuric acid , washed with water dried red standby ; C. bath is transferred to the backup tank , at 3-5 g / l dissolved slowly into the active carbon tank solution , to be dissolved completely , adsorption 4-6 kid, filtered bath with 10um of PP filter plus filter aid powder to clean the work tank , into the anode , hanging into the electrolytic plates , press 0. 2-0. 5ASD current electrolysis current density low for 6-8 hours , D. by laboratory analysis , adjusting slot sulfate, stannous levels to within the normal operating range ; supplement tin additives Hall cell test results ; E. electrolytic plate board to be after the surface color uniformity , stop electrolysis ; F. plated OK to try . ;

⑤ When supplementary drugs, such as a large amount of stannous sulfate , sulfuric acid ; should be added at the low current electrolysis ; additional acid should pay attention to safety , the addition amount is large ( more than 10 liters ) should be several times slower additional ; otherwise it will create the bath temperature is too high , stannous oxide , accelerate the aging of the bath ;

⑥ drugs add formula:

Stannous sulfate ( unit: kg ) = (40-X) × tank volume ( L ) / 1000
Sulfuric acid ( Unit : L ) = (10%-X) g / L × tank volume ( liters )
Or ( Unit: L ) = (180-X) g / L × tank volume ( liters ) / 1840

( Eight ) nickel

① purpose and function: a nickel plating layer as a barrier layer is mainly a copper layer and a gold layer, mutual diffusion preventing bronze affect weldability and board life ; nickel layer while also greatly increased the primer layer of gold mechanical strength ;

② full board copper plating process parameters : nickel additives added generally in accordance with a thousand ways to supplement or hours based on actual production board effects, add the amount of approximately 200ml/KAH; graphics nickel plating current calculation generally 2 amps / sq points m by the board electroplating area ; nickel- cylinder temperature is maintained at 40-55 degrees , the general temperature of about 50 degrees , so the nickel cylinders to install heating , temperature control systems ;

③ process maintenance :

According to a thousand hours a day to replenish the nickel plating additive ; Check if the filter pump is working properly, without leakage phenomenon ; every 2-3 hours with clean wet rag and cleaned cathode conductive rod ; week to regularly analyze copper cylinder nickel sulfate ( nickel sulfamate ) ( 1 times / week ) , nickel chloride ( 1 times / week ) , boric acid ( 1 times / week ) content , and through the Hall cell test to adjust nickel additive content , and timely supplement related materials ; week to clean the anode conductive rods, electrical connectors at both ends of the tank , replenish nickel- titanium anode basket in the corner , with a low current 0 2 0 5ASD electrolysis 6-8 hours ; monthly anode should be checked the titanium basket bags without damage, damage should be replaced ; and check the bottom of the basket is stacked titanium anode anode mud, if any should be clean ; continuous filtration with carbon core 6-8 hours , while low current electrolysis impurity ; about every six months to determine whether the specific needs of large processing ( activated carbon powder ) according to the bath pollution status ; biweekly drug pump replacement filter cartridges ;

④ large Handler : A. Remove the anode , the anode pouring , cleaning the anode , and then placed in a nickel package corner barrel, with micro- corrosion agent roughening the surface of the nickel corner to a uniform pink can, red dry after washing , loading the titanium into the basket , square into the acid bath spare B. titanium anode baskets and anode bags into 10% lye soaked for 6-8 hours , washed red dry , then 5% dilute sulfuric acid soaked , washed red dry spare ; C. the bath is transferred to the standby tank , add 1-3ml / 30% hydrogen peroxide of L , start heating until the temperature is about 65 degrees to the air added with stirring , stirred for 2-4 hours heat the air ; D. switched off air agitation of 3-5 g / l active carbon powder slowly dissolved into the bath , to be dissolved after a thorough , open air mixing, so heat for 2-4 hours ; E. Turn off the air mixing , heating, allow the activated carbon flour slowly settling to the bottom ; F. until the temperature dropped about 40 degrees , with 10um filtered bath of PP filter plus filter aid powder to clean the work tank , open air mixing, into the anode , linked into the electrolytic plates press 0 2-0 5ASD current electrolysis current density low for 6-8 hours , G. through laboratory analysis , adjusting tank or amino acid, nickel sulfate , nickel chloride , boric acid levels to within the normal operating range ; . according to Hall nickel plating tank test results supplement additives ; electrolytic plate board until after the plane H. uniform color , you can stop electrolysis, and then press the 1-1 5ASD electrolysis current density of about 10-20 minutes activating the anode ;. I. trial plated OK to .

⑤ supplementary drugs, such as a large amount of nickel sulfate or nickel sulfamate , nickel chloride when , after the electrolysis should be added at the low current ; additional amount of boric acid should be added into the anode bag hanging in a clean, Nickel cylinder can not be directly added to the tank ;

⑥ After a proposed increase recycling nickel washed with pure water, open cylinder , the cylinder can be used to supplement the nickel due to warming and volatile liquid , then recovered secondary countercurrent washing rinse ;

⑦ drugs add formula:

Nickel sulfate ( unit: kg ) = (280-X) × tank volume ( L ) / 1000
Nickel chloride ( unit: kg ) = (45-X) × tank volume ( L ) / 1000
Acid ( unit: kg ) = (45-X) × tank volume ( L ) / 1000

( Nine ) gold plating :

Divided into hard gold plating ( gold alloy ) and water gold ( pure gold ) process , consistent with hard gold -plated soft gold bath composition , but a few more hard gold tank trace metals nickel or cobalt or iron and other elements ;

① purpose and effect : gold as a precious metal , has good weldability, oxidation resistance , corrosion resistance, contact resistance, good abrasion resistance , etc. alloy fine features ;

② current PCB gold plating bath tank mainly citric gold , with its simple maintenance , easy to operate and widely used ;

Gold ③ water content control 1 g / l , PH value of 4 5 or so, the temperature 35 degrees , the proportion is about 14 degrees Baume , the current density is about 1ASD.;

④ There are major drugs added to adjust the PH value adjustment salts and acid salts of basic adjustment , and adjusting the proportion of the conductive salt is a salt of gold plating additives and supplements and the like;

⑤ to protect the gold cylinder , the cylinder should be added before a citric acid leaching gold slot , which can effectively reduce pollution and keep the gold cylinder gold cylinder stable ;

⑥ after plating a gold plate applied recovered as washing with pure water , and can also be used to supplement the level variation evaporated gold cylinder , then recovering the secondary countercurrent washing with pure water after the washing into the gold plate 10 g / l of alkali gold plate to prevent oxidation ;

⑦ gold cylinder of platinum -plated titanium mesh should be used as the anode , usually stainless steel 316 easy to dissolve , leading to contamination of nickel-iron -chromium and other metals gold cylinder , resulting in gilded white, dew -plated , black and other defects ;

⑧ gold cylinder core organic carbon pollution continuous filtration applications , and add the right amount gilded additives.

The importance of the printed circuit board plating

In the printed circuit board, copper is used to interconnect components on a substrate , although it is to form a conductive path printed circuit board graphics board good conductor material , but if prolonged exposure to air , but also it is easy to lose luster due to oxidation , corrosion and loss suffered due weldability . Therefore, you must use a variety of techniques to protect the copper traces , vias , and plated through holes , such techniques include the organic coating, the oxide film and plating techniques .

The organic paint application is very simple, due to changes in concentration , composition, and the cure cycle is not suitable for long-term use , which may even lead to unpredictable variations in welding . Oxide film can protect the circuit from erosion , but it can not keep weldability. Metal plating or coating process is to ensure weldability and corrosion protection circuit to avoid the standard operation, the circuit board manufacturing plays an important role in the single-sided , double-sided and multilayer printed . In particular, the plating layer having a printed line of the weld metal has become a solder protective layer provided for the operation of a standard copper tracks .

In various modules interconnected electronic devices often need to use a printed circuit board connector with the mating connector housing and its contacts with the printed circuit board design with spring contacts . These contacts should have a high degree of wear resistance and contact resistance is very low , which requires rare metal plating layer thereon , wherein the metal is gold most commonly used . Also in online printing can also use other coated metals, such as tin -plated town , sometimes also copper traces in some regions .

Another line is printed coated copper organic, typically a solder mask , in those places without welding technique using a screen printing film , covered by a layer of epoxy resin . This flux covered with a layer of organic- electronic exchange process does not require , after the circuit board is immersed in electroless plating solution , a compound having a nitrogen tolerance can stand attached to the exposed metal surface and is not absorbed by the substrate .

Sophisticated technology and stringent environmental and safety requirements of adaptive electronic products need to promote plating practice has made considerable progress , which is clearly reflected in the manufacturing of high complexity, high resolution multi- substrate technology .

Development occurs in electroplating , through the development of automated computer -controlled plating equipment , conduct chemical analysis of organic and metallic additives in highly complex instrument technology, and precise control of the chemical reaction process technology, electroplating technology to achieve a high level.

Increasing the growth of the metal layer in the circuit board , there are two standard lines and vias Method : full line plating and copper plates , are described below .

1. line plating

The receiving process of the copper layer and the etching resist is generated only in the metal plating and the circuit pattern design where the through hole . In the electroplating process line , added on each side of the line and the width of the pad increases the thickness of the plating surface roughly therefore need to leave remaining on the original film.

Basically in line plating should be carried out most of the copper surface resist mask , only there the line and pad areas such as circuit pattern plating . Since the surface area to reduce the need for plating , the current supply capacity is usually required can be significantly reduced , in addition , when the contrast inversion photopolymer dry film plating resist ( a type most commonly used ) , its negative film You can use relatively inexpensive laser printing machine or pen production. Small amount of consumption of copper plating anode line , needs to be removed during etching of the copper also less, thus reducing the cell analysis and maintenance costs . The disadvantage of this technique is needed before proceeding etched circuit pattern plating tin / lead or an electrophoretic resist material , prior to application of solder resist and then removed.

This increases the complexity , an additional set of wet chemical solution treatment process.

2. full board copper

In this process, the entire surface area for both copper and drilling , without the need to pour some of the copper surfaces resist , etch resist and plating metal . Even for a medium- sized printed circuit board is concerned , which also need to be able to provide a large electric current excavation, it can be made into a smooth and easy to clean , bright surface of the copper used for the subsequent step . If no photo plotter , the negative film is required to expose a circuit pattern to become more common in dry film photoresist contrast inversion . The whole plate was etched copper circuit board , the majority of the plated material on the circuit board will be removed again , because the etchant solution containing copper increased anode corrosion by the additional burden is greatly increased .

For the manufacture of printed circuit board is concerned, is a better line plating method, the standard thickness as follows:

1) Copper

2) tin - lead (lines, pads, vias)

3) Nickel 0.2mil

4) Gold (connector tip) 50μm

The reason to maintain the electroplating process parameters to provide such a highly conductive coating to the metal, good weldability and high mechanical strength to withstand the panel terminal part from the surface of the board and to fill the plated through-hole copper; required ductility.

Printed circuit board plating production line Maintenance

In the printed circuit board production process, the plating coating directly affects the back etching step, affecting the quality of the coating on the entire mass of the board is critical. Plating equipment account for a large proportion of the respective printed circuit board production enterprises, and in order to ensure the normal operation of plating equipment to ensure proper care and maintenance is very important to the stability during operation and plating equipment life, equipment, This article is to introduce the printed circuit board production enterprises commonly used in electroplating equipment maintenance and maintenance.

1. Types of equipment

In the printed circuit board production process, plating equipment is mainly used in two ways, one is horizontal plating line, one is vertical plating line. These two different structures of the plating apparatus, the main circuit board is transported in different ways, conveying plate used in the device structure is not the same, and therefore slightly different for maintenance.

2. Daily care and maintenance methods

2.1 Maintenance of the tank

The main difference between the vertical and horizontal plating line plating line is a different way of transporting the board, and for the care and maintenance of the essence of the method on the tank or less. 7d each wash tank to be cleaned on a pickling tank, once cleaned and replaced its bath; spray device on the tank body to conduct an inspection to see whether the blockage occurs, for obstruction appears to be timely and clear ; of copper trough, conductive bearings and tin anode and Firewire slot on the contact position, be available and sandpaper to polish cloth to wipe clean when a cleaning; slots for copper, tin trough titanium basket, tin basket conduct an inspection, replacement of rotten titanium basket bags, tin basket and add ball, tin, copper ball at 7d finished adding, after tin, copper plating is required for tank, electrolytic tin plating tank. 7d also high, low current way of pre-production, so that the newly added ball, tin finished, stable performance manufactured before production. 90 To each anode copper balls and bags for a cleaning. Each 120 ~ 150d using activated carbon filters to clean the bath once, filter impurities in the bath, on the tin bath once cleaned.

2.2 vertical plating line vibration mechanism Maintenance

On the vertical plating, to ensure uniformity and effectiveness hole copper electroplating copper surface, the vibration plate will swing, there will be vibration swing mechanism on the tank. 30d To gear check to see if it is working properly, check the tightness; shock mounting the motor bolts to check tightness; checking vibration rubber wear, for more serious wear and tear, to timely replace [ 1]. 180d case of power line contact junction box to check for loose joints appear to be fastened in a timely manner, the melting of the wire insulation or aging power lines, to promptly replace the power cord, ensure that the insulation resistance between the power cord; To all the bearings on the vibration mechanism to conduct an inspection on a grease for bearings to severe wear for timely replacement.

2.3 vertical plating lane Maintenance

Vertical plating line is the use of traffic, linked to a circuit board for delivery. A week to once a crane and hung a clean (and linked with driving without disassembling), make it look neat and clean, you can use a rag to wipe clean when washing and use sandpaper. 30d conduct an inspection of the rack, the rack view breakage; against driving motor and reducer to conduct an inspection and maintenance, to view its entire transmission to ensure their normal operation. 180d on the road and linked with an in-depth cleaning and maintenance, to rack removed from the road down to clean [2].

2.4 Horizontal Conveyor plating Maintenance

Horizontal conveying device uses a wheel plating line, the use of rotating rollers continuity of the circuit board into each slot, therefore, maintain lines of horizontal and vertical plating plating lines to carry a number of different devices. 7d level of wheel plating line were last cleaned, the cleaning roller foreign matter adhering to ensure board clean sheet at the time of delivery; want to connect the actuator to check to check whether there is loose. Each 180d conduct an inspection of the wheel, inspect the tires for wear on the wheel appears timely replacement of worn to ensure that the phenomenon does not occur at the time of delivery pallets plate; want to drive gear, drive shaft and the entire transmission system carry out a check for problems timely repairs.

2.5 Maintenance of filtration system

7d cartridge filtration system to conduct a check to see whether there is leakage cartridge. 10 ~ 15d every time you want to filter cotton core once cleaned or replaced. 30d to replace the filter carbon core, in order to ensure the quality and filter traffic filtering machines; want to conduct a clean filter pump and clean the pump filter hood and filter. Check the pump in contact situations 30d motor power cord connector, found loose in time to be tightening, to be replaced with new wire aging wires to ensure good contact and secure insulation to protect the motor.

2.6 Maintenance of other parts

7d to the output power of the power supply checked twice; want to power, cooling, electrical control of the popularity of the radiator checked, dus, t, clean and prevent its impact cooling. 30d electrical devices for electrical units to check if there is damage and corros, ion to timely replacement;

Check all connectors and, if exposed, and Weld phenomena such as virtual access to timely repair, corrosion and damage, if any, should be replaced; Check the contactors and relays, if contact is bad or contact adhesion, to be replaced; main parameter checking capacitors, reactors and resistors and other components, if there is an exception, to be replaced soon.

Automatic feeding system, 7d to check the calibration once. 7d to clean up the scale and dirt on the electric heater, electric heater to prevent the internal temperature is too high.

For all water, gas line system, 7d conduct an inspection to see its presence appears to run, leak fluid phenomena appear to run pipe to leak fluid phenomena timely maintenance and replacement of them.

3. Discuss the long-term maintenance downtime before

If the device is planned downtime, to its maintenance, so that it will not be eroded when the shutdown process of aging, to do: clean the floor, wipe clean water on the ground, the ground remains dry and make the machine table , tank, driving, hanging with must be kept clean and dry; all motors is best to use plastic wrap good protection; inject grease all bearings to rust; syrup all piping in place and clean all clear; Filter clear syrup bucket, put a clean filter; remove filter cartridge clean; heater tank should be all clean, except for the dirt to keep dry.

Printed circuit board production applications plating equipment, due to the different production processes used by different manufacturers, there will be some differences in the equipment, so there will be some differences in the maintenance methods, but the equipment must be timely and correct maintenance, should not result in time production schedule, output and ignore the maintenance and repair of equipment, proper maintenance is only done in a timely manner in order to ensure the normal operation of the equipment, stable performance, ensure the production yield and quality.

Printed circuit board electroplating

A method for plating a printed circuit board , comprising : a first step of providing a substrate , said substrate having a plurality of connection pads connected to the connection pads and the circuit pattern ; the second step using certain circuit pattern , provided on the circuit pattern on the substrate surface as the power connecting portion and the connecting portion is connected to the external power supply ; covered with a protective film to prevent the plating surface of the substrate except the third step it is connected to the pad outside the shield ; by connecting the power supply portion is connected to the pad , and a fourth step of plating layer is formed on the connection pads ; fifth step , and the power connection part and the external power supply disconnection . With this method, you can get a printed circuit board without the need for gold-plated power cord.

A printed circuit board plating method further include : a first step of providing a substrate having a plurality of sides of the substrate and the bonding pad and the pad is connected to the ball bonding pad and a circuit pattern spherical pad ; certain circuit pattern using a second step of providing a circuit pattern on the substrate surface as the first and second power supply connection portion , and a first connecting portion connected to the external power supply ; covered with a protective film to prevent plating with spherical pad is formed in the third step on the surface of the substrate be shielded ; supplied to a fourth step of forming the bond pad layer on the plating bond pads of the first power supply through the connecting portion ; so that the first and a fifth step of connecting the power supply circuit section and the external ; the second power supply is connected to the connecting portion with the external power supply and prevent the plating film is formed on the pad is covered with a spherical surface of the substrate on which the sixth step of masking its ; and a second connection part and the external power supply circuit to an eighth step ; connecting portion to the second power supply pad to the seventh step of the spherical gold plating layer is formed on the pads through ball .

Printed circuit board plating technology level

First. Overview

With the rapid development of microelectronics technology , printed circuit board manufacturing to multi-layered , laminated technology , rapid development and integration capabilities direction . Promote extensive use of printed circuit design tiny holes , narrow spacing, thin wire for circuit design ideas and graphics , making printed circuit board manufacturing higher technical difficulty , especially multilayer aspect ratio vias and integrated over 5:1 deep blind hole laminates are widely used to make conventional vertical plating process can not meet the high quality and technical requirements of high reliability interconnect holes. The main reason for the principle of need from the plating current distribution on the analysis , the actual plating found distributed through the current presentation drum-shaped hole , the hole current distribution occurs gradually decreased from the edge to the center of the well bore , resulting in a large amount of copper deposited on the surface and hole can not ensure that the standards required thickness of the central hole copper copper layer should reach the site , sometimes a very thin layer of copper or no copper layer , can cause severe irreparable damage , resulting in a lot of scrap plywood . To solve the problem of product quality in mass production , are currently going to solve the problem from the current deep-hole plating and additives . In high aspect ratio copper plating of printed circuit board technology , most are high in auxiliary additive effect , with moderate stirring and the cathode air moving at a relatively low current density conditions. Make hole electrode reaction control area increased, plating additive effect to show up , plus improved cathode moving very beneficial bath throwing power , and the increasing polarization plating , coating electrical crystallization process nuclei formation rate and grain growth rate to compensate each other to obtain high toughness copper layer .

However, the case where the aspect ratio of the through -hole appears to continue to increase or deep blind holes , two steps process becomes weak, thus generating a horizontal electroplating techniques . It is to continue the development of vertical plating technology , which is developed on the basis of vertical plating process on the new plating technology. The key to this technology is adapted to be manufactured , supporting each horizontal plating systems , the ability to make high dispersion bath , with improvement in the power supply and other auxiliary devices , showing more excellent than the vertical plating the functional role .

Second, the principle of horizontal plating Introduction

Horizontal and vertical plating is a plating method and the same principle , must have a Yin and Yang , the electrode reaction to produce the main ingredient is energized so that the electrolyte ionized , the charged positive ions move toward the negative electrode relative to the reaction zone ; charged ions to the electrode the positive phase reaction zone moves , so have metal deposition coating and release the gas . Because the metal cathode deposition process is divided into three steps : the hydrated metal ions to the cathode diffusion ; second step is hydrated metal ions through the electric double layer , gradually dehydrated and adsorbed on the surface of the cathode ; Third step is adsorbed on the surface of the cathode into the electron accepting metal ions in the metal lattice . Cases from actual observation to the job slots can not be observed with the liquid electrode plating solution interface between the solid phase heterogeneous electron transfer reactions. Electrical double layer structure can be used in principle to the theory described electroplating , and when the electrode is a cathode polarization , the water molecules were surrounded with a positive charge and the cation , and the electrostatic force due to an ordered arrangement of the cathode near the closest center of the cathode composed of a cation and provided physiognomy termed Helmholtz (Helmholtz) an outer layer from the electrode distance of about about 10 nm . However, because the outer Helmholtz positive total charge carried by the cationic charge , the positive charge and negative charge are insufficient in the cathode . The farther away from the cathode bath affected convection cation concentration of the solution layer higher than the anion concentration . Because this layer is the outer Helmholtz electrostatic force is smaller than , but also affected by the thermal motion of the outer Helmholtz cation arrangement is not as close and neat , this layer is known that the diffusion layer . The flow rate of the diffusion layer thickness is inversely proportional to the bath . That is , the faster the flow rate of the bath , the thinner the diffusion layer , the anti thickness of the diffusion layer thickness of about 5-50 microns. Farther away from the cathode , convection layer known that the bath to reach the main bath . Because the convection of the solution can affect the uniformity of the concentration in the bath . Diffusion layer by plating copper ions migrate by diffusion and ion transport to the outer Helmholtz way . The main bath has copper ions by ion mobility convection and its transport to the cathode surface. Where in the horizontal plating process, the copper ions in the plating solution is supplied to the vicinity of three ways by the , cathode for an electric double layer is formed .

Bath convection is generated inside the external were mecha, nically stirred and the stirring pump , its oscillating or rotating electrode method , and the temperature difference caused , by the flow of the plating solution . The closer the place where the electrode surface of the solid , due to the friction resistance of the flow of the plating solution becomes more and more slowly , the solid electrode surface convection velocity is zero at this time . Rate between the bath from the electrode surface to the formation of convection known that the flow gradient layer interface layer .

Times the thickness of the interface layer of the flow around the diffusion layer thickness , the diffusion of ions in the transport layer is hardly affected by the convection .

In the role of electricity and drinking places , and ion plating solution caused by static electricity known that the ion mobility ion transport . Its rate of migration by the following formula : u = zeoE/6πrη to . Wherein the ion migration rate u , z is the charge number of ions , eo is the charge of an electron ( i.e. 1.61019C), E is the potential , r is the radius of the hydrated ions , η is the viscosity of the plating solution . According to the calculation formula can be seen , the greater the potential E landing  plating solution viscosity is smaller, the faster the rate of ion migration .

The electrodeposition theory , electroplating , printed circuit board is located on the cathode electrode of a non- ideal polarization adsorbed on the surface of the cathode and copper ions are reduced to obtain electron copper atom , leaving the copper ion concentration near the cathode reduced. Thus , the cathode will be formed near the copper ion concentration gradient. Copper ion concentration lower than the concentration of the main plating bath of this layer is a diffusion layer of the bath . The main bath and high concentration of copper ions , a copper ion concentration in the cathode to the lower vicinity of the place , the diffusion constantly replenish the cathode region . A printed circuit board similar to the cathode plane , the size of the current diffusion layer has a thickness in the relationship of COTTRELL equation:

Where I is the current , z is the charge number of the copper ion , F is the Faraday constant , A is the surface area of ​​the cathode , D is the diffusion coefficient of copper ion (D = KT/6πrη), Cb is the concentration of copper ion in the bath main body , Co cathode copper ion concentration of the surface , D is the thickness of the diffusion layer , K is a constant wave Man (K = R / N), T is the temperature , r is the radius of a hydrated copper ions , η is the viscosity of the plating solution . When the cathode surface of the copper ion concentration is zero, the current is called the diffusion limit current ii:

As can be seen from the above equation , the diffusion current is determined by the size limit of the thickness of the copper ion concentration in the bath main body , and the diffusion coefficient of copper ion diffusion layer . When a high concentration of copper ions main bath , the copper ion diffusion coefficient is large, thin diffusion layer, the greater the diffusion current limit .

According to the formula that, to achieve a higher current limit value, it must take appropriate technical measures , that is, the use of heating process method . Elevated temperature such as the diffusion coefficient becomes larger , faster flow rate can be obtained by making a thin but uniform eddy diffusion layer . The above theoretical analysis, increased body copper ion concentration in the bath to raise the temperature of the plating solution , as well as faster flow rate, etc. can increase the limiting diffusion current, and achieve the purpose of speeding up the plating rate from . Based on the level of the plating bath to accelerate the formation of the vortex convection velocity can be effectively reduced the thickness of the diffusion layer is about 10 microns. When the horizontal plating system plating , the current density up to 8A/dm2.

The key printed circuit board plating , that is how to ensure uniformity of substrate vias on both sides and the inner wall of the copper layer thickness. To obtain uniformity of coating thickness , it is necessary to ensure that both sides of the bath and the flow rate of the through hole of the printed circuit board to be fast and have to be consistent to obtain a uniform thin diffusion layer . To achieve a uniform diffusion layer is thin , the structure of the current level of the plating system , despite the installation of the system within the plurality of nozzles capable of playing in the bath fast vertical PCB, in order to accelerate the flow of the plating solution in the through -hole speed , resulting in fast flow rate of the bath , on the lower substrate and the through hole to form a vortex , but lower than the diffusion layer uniform . Generally, however, when the sudden inflow of the bath through the narrow hole through the entrance hole of the bath will have the reverse flow phenomenon , coupled with the current distribution of the primary impact , often resulting in the entrance of the hole portion speech electroplating due to the tip effect leads through thick copper layer thickness , constituting the inner wall of the through-hole copper plating dog bone shape . Plating the through hole according to the size of the flow vortex and a reflux state, i.e. , the state of conduction of the plated through hole quality analysis can only determine the control parameters to achieve the plating thickness of the printed circuit board by the process uniformity test. Because the size of the eddy and backflow has still not informed by theoretical calculation , only the use of measured process method . From the measured results that , to control the uniformity of the through-hole plating copper layer thickness , it is necessary to adjust the process parameters controllable through-hole printed circuit board according to the aspect ratio , or even choose electroless copper plating solution high dispersion capability , and then add the appropriate additives and improved power supply that uses a reverse pulse current plating copper plating was to obtain a high distribution capabilities.

Especially laminates increase the number of micro blind hole , only to horizontal plating plating system , but also to promote the use of ultrasonic vibration micro blind hole bath replacement and circulation , improve power supply and then using reverse pulse current and the actual test the data alignment controllable parameters , you can get satisfactory results.

Third, the level of the basic structure of the plating system

According to the characteristics of the level of the plating , the printed circuit board which is placed in a vertical manner from the surface of the plating bath into a parallel manner . Then the printed circuit board as the cathode , and the current level of supply and some systems using a conductive plating and the conductive clamps two wheel . From the operating system is easy to talk about , with roller conducting more common modes of supply . Horizontal plating system as a cathode conductive roller addition , it also has a transfer function of the printed circuit board .

Each of the conductive roller are mounted with a spring means , which aims to adapt to different thicknesses of printed circuit boards (0.10-5.00mm) require plating . But in the plating bath will be in contact with the site may be plated with copper layer , the system will not run for a long long time face . Therefore, the current level of the plating system manufactured , most of the cathode to the anode is designed to be switched , and then use a set of auxiliary cathode can be plated on the cross roller electrolytic copper dissolved. Respect for the repair or replacement purposes, the new design also takes into account the plating loss of parts to facilitate easy removal or replacement. The anode is used to adjust the size of the array of insoluble titanium basket , printed circuit boards were placed in a vertical position , built with spherical diameter of 25mm , an amount of 0.004-0.006 % of soluble phosphorus copper cathode and anode is the distance between 40mm.

The bath flow pump and nozzle system is used consisting of the bath in the plating tank after closure , the flow of alternating up and down rapidly , and to ensure uniformity of the flow of the bath . Playing in the bath vertical printed circuit board , the printed circuit board to form the red wall jet vortex . The ultimate objective was achieved on both sides of the printed circuit board through holes and a vortex flow of the plating solution rapidly . Another tank equipped with a filter system wherein the filter is used for the 1.2 micron mesh to filter particulate impurities generated during plating to ensure a clean, pollution-free bath .

In the manufacture of horizontal plating system , but also take into account the ease of operation and automatic control of the process parameters . Because the actual plating , with the size of the printed circuit board size, the different sizes through-hole aperture size and the required thickness of copper , the transmission speed , the printed circuit board between the distance , the size of the pump horsepower , nozzle set the level of process parameters such as the direction and current density are needed for the actual testing and adjustment and control , in order to obtain the copper layer thickness meet the technical requirements . Shall be controlled by computer . In order to improve production efficiency and product quality and consistency of high quality and reliability , the through-hole printed circuit board before and after treatment ( including plated-through holes ) in accordance with the process of the program , a complete horizontal plating system , is the development of new products to meet the listing needs.

Fourth, the development level of the level of development advantages plating plating technology is not accidental, but a high-density , high-precision , multi-function , high aspect ratio multi-layer printed circuit board products require special features is the inevitable result. Its advantage is than it is now used in a vertical hanging plating method is more advanced , more reliable product quality , to achieve large- scale production .

Compared with vertical plating process method has the following advantages:

( 1 ) accommodate a wide range of sizes , without the need for manual racking , to achieve full automation of the process of improving and ensuring the job without damage to the substrate surface , the realization of large- scale production is extremely beneficial.

( 2 ) In the process of review, without leaving clamping position , increase the usable area , greatly reduce the loss of raw materials.

( 3 ) plating with full level of computer control , the substrate under the same conditions to ensure that each surface of the printed circuit board hole plating uniformity.

( 4 ) From the management perspective , from the plating tank cleaning, and replacement of the plating solution is added , can be fully automated operation , will not cause loss of control of management problems because of human error.

( 5 ) can be measured from the knowledge of the actual production , because the use of multi- level horizontal plating cleaning, significant savings in the amount of wash water and wastewater treatment to reduce the pressure .

( 6 ) Since the system uses closed-end jobs , reduce the direct impact on the operating room evaporative heat pollution and the environment of the process , greatly improve the working environment . Especially due to the reduction of heat loss , saving unnecessary energy consumption and greatly improve production efficiency while baking sheet .

Horizontal plating technology, completely in order to meet the high aspect ratio through-hole plating needs. However, due to the complexity and particularity of the plating process , the plating system design and development level there are still a number of technical problems. It remains to be to be improved in practice . Nevertheless, the use of horizontal plating systems for printed circuit industry is a great development and progress. Because this type of equipment in the manufacturing aspects of the use of high-density multilayer boards , showing great potential , it can not only save manpower and operating time and the production speed and efficiency than the traditional vertical plating line to be high . And reduce energy consumption, reduce waste effluents treatment needed , but also greatly improve the process environment and conditions , to improve the quality standards of the plating layer. Where the horizontal plating line for large-scale production of 24-hour operation , the horizontal plating line when debugging a little difficult compared to some of the vertical plating line , once debugging is very stable , but in the course of the bath should always monitor bath adjusted to ensure the long time stability.

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