Double-sided circuit boards

Foreword

High-tech development, people need high performance, small size, multi-functional electronic products, printed circuit board manufacturing also prompted to light, thin, short, small development, limited space, to achieve more functionality, larger wiring density, pore size and more small. From 1995 to 2005, the bulk mechanical drilling down from the original capacity of the smallest aperture of 0.4mm to 0.2mm, or even smaller. Metal hole diameter is also getting smaller and smaller. Metallized hole interconnections between layers depends, directly related to the quality of the printed circuit board reliability. With the narrow aperture, the original did not affect the larger pore debris, such as grinding brush debris, ash residue in the hole once inside, will make the electroless copper plating copper out of action, there is no hole copper, become holes metalized killer.

Brief introduction

Double-sided circuit board PCB board is a very important one PCB board, double-sided circuit boards PCB metal base plate on the market, Hi-Tg heavy copper circuit boards, flat meandering sided circuit boards, high frequency PCB, mixing high-frequency dielectric base sided circuit boards, it is suitable for a wide range of high-tech industries such as: telecommunications, electricity, computers, industrial control, digital products, science and technology equipment, medical equipment, automotive, aerospace, defense and so on.

Double-sided PCB board process

Double-sided PCB usually epoxy glass fabric copper-clad board manufacturing. It is mainly used for high performance requirements of communications electronics equipment, advanced instrumentation and computer and so on.

Production processes are generally divided into two-panel wire method, plugging holes law, a masking pattern plating method and etching several, an etching pattern plating production process.

Process

Double-sided tin plate / Immersion Gold board production process:

Drilling is expected to open ------ ----- ---- Shen copper wiring diagram electrical ---- etching ----- --- solder --- Character ---- HAL ( or Immersion Gold) - gong-v cut (some boards do not need) ----- fly measured ---- vacuum packaging

Double-sided gold-plated plate production process:

Drilling is expected to open ------ ----- PTH ---- Line ---- diagram electrical --- gilded ---- etching ---- solder ---- characters - --- gong --- v --- cut --- fly measured vacuum packaging

Multilayer tin plate / Immersion Gold board production process:

Is expected to open the inner ----- ------ laminated ---- Drilling --- Shen --- copper wiring diagram electrical ---- ---- etching ----- solder --- Character ---- HAL (or ENIG) - fly gong-v cut (some boards do not need) ----- measured ---- vacuum packaging

Multilayer gold plate production process:
Is expected to open the inner ----- ------ laminated ---- Drilling --- Shen --- copper wiring diagram electrical ---- ---- gilded ---- etching - - solder ---- character ----- gongs --- v --- cut --- fly measured vacuum packaging

1, pattern plating process

Foil covered board ---- cutting ---- red diamond drilling reference holes ---- NC ---- examination ---- deburring ---- thin copper plating thin copper plating ---- ---- examination ---- brush plate ---- foil (or screen printing) ---- exposure and development (or curing) ---- Graphics ---- inspection repair plate plating (Cn ten Sn / Pb ) ----- to film ---- etching ---- test repair nickel-plated gold-plated plug board ---- Cleaning ---- Electrical ---- melt-off detection ---- cleaning - --- screen printing solder solidified ---- Graphics ---- ---- curable screen printing marks, contouring ---- ---- ---- examination ---- packing cleaning and drying - - Finished.

Process "thin copper plating thin copper plating ----" These two processes available "thick copper plating" a process of substitution, both have their advantages and disadvantages. Pattern Plating - double the legal system faces etched metal plate is a typical process sixties and seventies of. Eighties bare copper solder mask coating process (SMOBC) gradually developed, particularly in the manufacture of precision dual panel has become a mainstream technology.

2, SMOBC process

The main advantage is to solve the SMOBC board solder bridging short-circuit between the fine lines, and because a constant proportion of tin, a better weldability and storage than the melt plate.

Many manufacturing method SMOBC board has passed on standard graphics tin plating method of subtracting SMOBC process; with tin or tin, immersion tin plating instead of subtracting law SMOBC pattern plating process; plugging holes or hole method SMOBC masking process ; additive method SMOBC crafts.

The following describes the graphical passed on tin plating process and blocking the hole method SMOBC SMOBC process.

Graphics passed on tin plating method is similar to the process of SMOBC graphics plating processes. Changes only after the etching.
Double-sided copper clad board ---- Graphic plating process according to the etching process ---- retreat tin solder ---- examination ---- Cleaning ---- Graphics ---- nickel-plated gold-plated plug ---- Plug taping ---- HASL ---- Cleaning ---- Screen Printing mark symbol ---- shape machining ---- examination ---- finished washing and drying ---- Packaging ---- Finished.

3, plugging holes law mainly process is as follows:

Double-sided foil covered board ---- Drilling ---- electroless copper plating copper ---- ---- entire board plugging holes ---- Screen Printing Imaging (As) ---- etching - - to screen printing material, plugging holes to solder material ---- Cleaning ---- Graphics ---- plug nickel, gold-plated plug taping ---- ---- HASL ----

The following step to the finished product on the same.

Process steps of this process is relatively simple, the key is to wash the ink plugging holes and plugging holes.

In the process of blocking the hole method without the use of plugging holes plugging holes and screen printing ink imaging, and the use of a special type of mask to cover up the holes dry, then the exposure is made just as the graphics, which is masking hole. Compared with the method of plugging holes, ink wash hole problem no longer exists, but there is a higher demand masking dry.

SMOBC process is the basis of a pre-emptive bare copper metal hole double panel, then apply hot air leveling process.

Production process

In the production of double-sided circuit board tools and materials needed to prepare roughly: double-sided copper clad laminates, thermal transfer paper, sandpaper, scissors, oil pen, hydrochloric acid, hydrogen peroxide, hand drill, iron, twisted pair, paper tape, iron , solder, rosin.

First, prepare the PCB map

1. Schematic

With 6 LED dynamic display circuit, for example, the circuit diagram is shown below. When the circuit diagram is more complex, the completion of the electrical circuit diagram ERC rules must pass inspection, using the default options, so as to ensure a serious problem circuit short circuit, such as the network name does not appear to repeat.

2. PCB plans

Both sides of the Double-sided circuit boards are called the top and bottom, top and bottom can be wiring, components generally placed at the top level. Top and bottom line through pin holes, vias are connected, when using automatic wiring, vias are added automatically when wiring. Due to the limitations of the particularity and hand-crafted double-sided circuit boards, double-sided circuit board design PCB plans when required to do the following modifications:

① Wire appropriately widened. If ordinary diameter Imm, power diameter 1.2mm, ground diameter 1.4mm. When the circuit board size allows, diameter should be as wide as possible and ensure that ground diameter> Power Wire> Normal diameter. By modifying the design rules to achieve the above requirements.

Protel DXP in another dimension units Inch (Imperil) and metric (MetrIC) are two, you can click [View] / [Toggle Units] switch between the two. For example, the ground wire diameter to 1.4mm, you can click the [Design] / [Rules], modify the Width Routing option in the dialog box that appears, you need to add to this rule for the new diameter, as figure.

② components appropriate to increase the pad. The default size of the package in the library is not suitable for handmade pad, it should increase the pad size.

Such as discrete components, manifold pad diameter can be set to 2mm, bridge pile can be set 3mm, other larger components, as the case may be. The above requirements can be achieved by modifying a whole. If all the circular pad having a diameter of 1.5mm diameter is set to 2mm, ProtELDXP overall principle is to modify the selected modified.

First, select. Use the mouse cursor to the overall need to modify one of the pad, the cursor refers only to the area of ​​the pad layer, right click, right-click menu appears, otherwise, right before the pop-up menu, and also select a pad or welding plate connection wire, or device, then only choose the pad (Pad). Right in the pop-up menu, point first to find similar objects (FindSimilarObjects), the pop-up dialog box to find similar objects, as shown above, our aim is to find the shape and dimensions are the same for all pads, points PadShape (AIILayers ), PadXSize (AllLayers) and PadYSize (AlILayers) any of the three columns (Any), drop-down arrow appears, there are three options are arbitrary (Any), the same (Same), different (Dfferent), are Select the same (Same), to find the conditions set similar items, click OK, the PCB workspace, pads are not satisfied with the conditions darken, will meet the conditions of the pad stand out, and the emergence of inspectors ( Inspector) dialog box as shown below, this dialog is a toolbar-style dialog boxes, can be placed on the left, you can hide this dialog box appears when you select Done.

The second step, modified. The inspector (Inspector) dialog PadXSize and PadYSize 1.5mm column are changed to 2mm, hit Enter to close the dialog box, change is completed. The question now is not modified or dark places, and how to restore it? Use the mouse to point the main toolbar buttons can be restored.

With this method not only can quickly make all the pad size to meet the requirements, but also to modify the overall diameter, hidden component values, character size, etc., where the bulk modify schematics and this is similar.

③ as far as the bottom of the priority routing. Double-layer circuit board components are placed at the top, when the hand-made circuit board, the lack of copper process, namely the pore walls can not copper, either a hole in the top of the copper film can not be connected with the underlying wire copper film conductors; insert integrated device After the device is connected to the pin only and can not connect the top and bottom copper wire copper film film conductors, such as still as single panel directly welded components, the circuit breaker and there will not be a lot of work. How to solve it? May first lead in the top hole of the copper wire penetrates the membrane over the line (1 to 2 fine copper wire), and the top weld, while the underlying components such as inserting components soldered with pins; resistors, transistors, etc. discrete components can be double-sided welding, the bottom and the top of the line can be connected via the device pins, so no welding over the line. This part of the workload is relatively large, so to minimize the lead in the top of the wiring should, after automatic routing, then the top lead by minimizing manual changes.

3. Print PCB diagram

Through a laser printer or an inkjet printer will print on thermal transfer paper PCB diagram.

(1) thermal transfer paper side very smooth paper, are sold on the market, A4 size. As we often see cellophane, promptly after use to throw away the stick side, can replace the thermal transfer paper. PCB plans to fight on the smooth side. Disposable paper heat transfer paper is not used multiple times, so as not to affect the life of the laser printer cartridges, the remaining transfer paper should be stored in a cool dry place, can not be affected by prolonged exposure to sunlight, or affect the transfer effect.

(2) Printer Setup ① Page Setup: Click [File] / [PageSetup], the dialog box shown above. Monochromatic color selection (mono), not gray (gray); proportion (scaling): Select scalingprint, scale select 1.00, not the default, otherwise the paper size and the physical size of the components are not equal and can not be installed. Other options are available by default.

② Advanced Options: In the dialog box shown on the map click - [Advanced] pop-up dialog box as shown below, in the dialog box where you can set the actual print layer PCB map, deleted or added as needed.

③ print top layer (TopLayer): Select multi (multi-layer, multi-select to print out the pads and vias), choose a mirror (mlrror), selected hole (hole, to facilitate drilling and drawings paste) as shown below .

④ Print underlying (Bottomlayer): do not choose a mirror, the other with the top.

Second, the thermal transfer

1. Conference Board

6 LED dynamic display circuit board size is 15cm × LOCm, after a good cutting board, first wash with detergent after sanding with fine sandpaper to smooth the edges and remove the surface oxide copper-clad, not too hard to leave grooves cause breakage.

2. Thermal transfer

The printed sheet of paper taped to the bottom of the Bonded Copper, drilled holes positioned in the space provided on the circuit board (PCB diagram can be added in a separate positioning holes, can also be a few scattered holes or vias lead substitute); When you paste the top drawing, remember to board alignment glare, light through the positioning hole through the bottom and the top of the drawing so that the positioning holes aligned as far as possible, this process is called positioning. If the positioning deviation is too large, component pads dislocation occurs at the bottom and the top, the board can not be used in severe dislocation.

After thermal transfer paper sticky, how to make thermal paper toner completely adsorbed on copper clad it? Due to heat transfer paper, high temperature, and printing on very smooth FIG PCB side, so when it is at a sufficiently high temperature, the toner is removed from the thermal transfer sheet to be adsorbed on copper clad. Heat Transfer Machine is a special equipment to implement this feature, when an amateur production of available iron ironing, temperature controlled at about 190 ℃, with a beat and a different direction, ironing around about Imin, the effect can be. Remember When completely cooled Bonded .

Copper, thermal transfer paper to tear.

If you worry about the effect of heating irons bad, handmade Shihai can be another way. The top and bottom of the PCB map Print (any printer can be) good quality and timely paste, poor quality adhesive vinyl adhesive is not strong on the back, easy to fall off when the corrosion. In the same manner as described above attached to the top and bottom in FIG copper clad, and then removed with a knife with a straight edge connection pads except excess paper, and finally to clean the glue remaining on the copper-clad, otherwise the impact and effectiveness of the corrosion rate. This method does not require any special equipment and the effect is good, the disadvantage is the circuit complex, time-consuming and more.

3. Line up

Whether using thermal transfer or thermal transfer with iron, the presence of certain more or less broken, do not worry, the oil can be an ordinary pen control PCB diagram manually fix.

Third, the corrosion will

After correction circuit board into hydrochloride + hydrogen peroxide + water (1:3:7) of the etching solution, this liquid is clear and transparent, can be clearly observed corrosion of the circuit board. In the corrosion process should pay attention to safety, choose a well-ventilated places, wear gloves. After a few minutes, you can get work fine double-sided circuit boards, remember to use clean water to wash away the residue of the corrosive liquid, but do not clean out the toner or timely stickers.

Fourth, drilling

Use hand drill or a small bench drilling, the hole can be drilled, division lead components larvae L, hand drill and then shun integrated circuits for high lead hole.

Because some holes need to wear a ~ 2 thin copper wires to connect a pin to the bottom and the top of the copper, it can be slightly larger than usual drill, such as 0.9mm, when the aperture is too small, easily integrated outlet inserted and over the line easily broken.

After all the holes drilled, with fine sandpaper or detergent to clean up the remaining toner or timely stickers. PCB finally produced, the following is soldered circuit boards.

Fifth, the circuit board soldering

1. Inspection

Because it is handmade, prior to welding, by visual observation or multimeter to measure to see if there is an open or short circuit, timely correction, focus on checking the top of a short circuit, because the components installed in the top floor, leads to some cover, if there is a short circuit , it will be particularly time-consuming maintenance.

2. Soldering through-hole

Double-sided circuit boards is more complex, there must be a certain order when welding, soldering all generally the first vias, due to design PCB diagram, component pads and vias of different sizes, it is easy to distinguish, in the past when welding larvae L in 1 to 2 through copper wire or 0.5mm hard, after both the top and bottom weld, cut off the excess parts.

3. Welded over the line

To make the top neat appearance, do not use double-sided welding, so that all leads to the top of the copper film lead wire holes are to be welded over the line, in order to avoid a short circuit, over the line to flatten the top of the hole to be drawn with a lead wire to a copper film is consistent In the lead away from the hole at the weld Imm; while the bottom without welding, cut off the excess part of the lcm reserved.

4. Welded components

Over the hole and over the line after welding, soldering components is down, and generally is based on mounting height components from low to high welding.

Focus is on integrated outlet, to align all the holes when inserted, even forced, under pressure, be careful not to bore over the line broke, and then the bottom line reserved lcm had filed with the pin and welded together and cut off the excess part of the post.

Six, power test

Check before energizing a seamless welding, Weld, wrong welding, and measuring the resistance between power and ground with a multimeter, the resistance is too small may short circuit, then power to exclude test can achieve the desired functionality.

Hole Mechanism

Bonded Copper drill on the first punch, and then after electroless copper plating to form copper plated through holes. Both on the hole metallization plays a vital role.

1, electroless copper mechanism:
In the double-sided and multilayer printed circuit board manufacturing process, are required for a non-conductive bare metal holes, that makes the implementation of electroless copper conductors. Electroless copper solution is a catalytic "oxidation / reduction" reaction system. In Ag, Pb, Au, Cu and other metal catalytic particles, the deposition of copper to.

2, copper plating mechanism:
Plating is defined using the power, in a solution of positively charged metal ions in place to push the surface of the cathode conductor layer. Copper plating is a "oxidation / reduction" reaction, the solution to copper metal anode copper oxide surface, and to become copper ions. On the other hand, the cathode reduction reaction is generated, so that the copper deposited as the copper ion. Both exchanged through medicine, chemistry to achieve the purpose of the hole of the exchange effect of a direct impact on the quality of the hole.

Debris plug hole

In the long-term production control process, we found that when the diameter reaches 0.15-0.3mm, the ratio of the plug hole 30 percent increments

A hole in the plug hole formation process questions:

When PCB processing, for 0.15-0.3mm holes, most still use mechanical drilling processes. In the long-term inspection, we found that the drilling, the impurities remaining in the hole

2, the following is the main reason for drilling plug holes:

When plugging holes appear, because the aperture is small, the former high-pressure washing sink copper, chemical cleaning is difficult to remove the debris inside the hole, stop the medicine electroless copper process water exchange in the hole, so that the role of electroless copper lost .

The laminated thickness of the drill when drilling the appropriate choice of nozzle plate, the substrate kept clean, not reused plate, effective cleaning results (using a separate vacuum control system) is a factor that must be considered to solve the plug hole.

Schematic drawing

1, there are many dedicated PCB mapping software, such as Protel, etc., you can draw a multilayer (including double-sided) circuit board diagram, is in position between the multi-aligned, and vias between layers line connectivity, to achieve cross-wiring, convenient layout. After completion of the layout can be made by a professional factory to a specific circuit board.

2, double-sided circuit board to turn into a circuit schematic drawing can be in two steps. The first step: Symbol first major components such as IC board painting by location to the paper, the connectivity and peripheral components of the foot properly arranged and painted to complete the sketch. Step two: analysis theory, according to customary law to draw schematics ready. Also can make use of circuit schematics software, connect the rafts components, and then use its automatic layout function finishing.

Double lines on both sides of the panel to be accurate alignment, positioning of the two sharp tweezers, flashlight light transmission, multimeter off and other methods to determine the joints and lines of communication with and go, but also to remove the components necessary to observe when Trend lines below it.

Double-sided PCB board proofing

Double-sided PCB proofing, the most commonly used processes. Meanwhile rosin process, OSP process, gold plating, immersion gold, silver these processes, in the dual panel also apply.

HASL process: good appearance, silvery white pad, the pad is easy on the tin, welding easy, inexpensive s.

Sikkim process: stable quality, typically used for IC bonding under the circumstances.

Difference sided PCB board

The difference between single-sided double-sided PCB board with the PCB, single-sided line is that only one side of the PCB, and then double-sided PCB line both sides of the PCB can be in the middle of the hole will be used double-sided PCB board line connected.

Double-sided PCB board PCB board production parameters with single-sided double-sided PCB board in addition to the production process is not the same, but also multi sank copper process, which is the double-sided circuit conduction process.

Parameters sided PCB board

Layers: 2 layers
Thickness: 1.6mm
Line width / spacing: 0.8mm/0.3mm
Material: FR-4
Copper thickness: 1OZ
Aperture: 0.6mm
Technology: HAL

Double-sided circuit board multilayer circuit board quality inspection standards

Double-sided circuit board multilayer circuit board quality inspection standards, in fact, many customers are not very clear, today put the details of the circuit board IPC international inspection standards to introduce to you, for your right to examine the quality of the PCB.

Scope: This standard applies to the substrate, metal coating, solder, character, appearance, holes, warpage testing products and other items. When this standard is not suitable for the manufacturing process of a hand or does not match the customer requirements, standards and customer agreements shall prevail.

Inspection requirements

A base (bottom) material:

1.1 leukoplakia \ netted \ fiber looming

White \ netted if they meet the following requirements may be accepted:
(1) does not exceed 5% of the board area
(2) the white line spacing of 50% from the non-busy

1.2 halos \ Layered \ blistering unacceptable.

1.3 foreign debris

Substrate foreign matter can accept if they meet the following requirements:
(A) a non-conductive material is identifiable
(2) reducing the wire spacing does not exceed 50% of the original wire spacing
(3) the maximum size of not more than 0.75mm

1.4 There shall be no copper layered substrate tilt, without fiber looming phenomenon.

1.5 base models meet the requirements

2. Warpage tolerance

Thickness Tolerance (mm) 0.2-1.2mm or more than 1.5mm
Dual panel to poor ≤ 1% ≤ 0.7%
MLB tolerance ≤ 1% ≤ 0.7%

3. Thickness Tolerance: plate thickness to meet customer requirements.
The maximum thickness of the finished multilayer rigid-sided tolerance in the following table

Dual panel thickness mm tolerance mm tolerance mm plywood
0.2-1.0 ± 0.1 ± 0.1
1.2-1.6 ± 0.13 ± 0.15
2.0-2.6 ± 0.18 ± 0.18
More than 3.0 ± 0.18 ± 0.2

4. Hole requirements:

4.1 aperture to meet customer requirements, its tolerance range is as follows:

Aperture mmPTH aperture diameter tolerance tolerance mmNPTH
Less than 1.6mm ± 0.08 ± 0.05
Greater than 1.6mm ± 0.1 ± 0.05

Note: The hole should meet the requirements of the bitmap drawings.

4.2 shall not porous, less holes and holes are not drilled, plug holes and so on.

4.3 There shall be no deformation of the hole (eg hole drilled into the oval hole, speaker hole, oval hole drilled hole, etc.).

4.4 There shall be no holes copper slag, dross, etc. affect the final aperture.

4.5 Components of the exposed copper hole wall does not exceed 3:00, the total area does not exceed 10% of the area of ​​the hole wall and is not exposed in a ring of copper.

Bore hole area not larger than 4.6 0.5mm, and each aperture of not more than 2:00 points, such holes does not exceed 5% of the total number of holes. Does not allow circular hole and hole-hole corner fracture or no copper, the MLB All electrical connections with the inner layer of metallized holes should not break holes.

4.7 is not allowed to have conductive vias.

4.8 folds hole plating shall meet the following requirements:
(1) does not result in poor inner connection.
(2) comply with coating thickness requirements.
Combining (3) and the well bore wall.

5. Pad (PAD)

5.1 pads at least 0.1mm, partial ring width deviation due to reduced line width of not less than 50% of the line connection,

5.2 pinholes, gaps result in a reduction of the area of ​​the pad the pad does not exceed 1/5.

5.3 SMD position allows three pinholes within 0.05mm2.

The solder resist Pad 5.4 as follows:
The total area of ​​(1) any two sides or three sides of the pad shall not exceed 10% of the pad.
(2) not more than 5% unilateral pad pad area.

a b a + b <10%

a a <5% Note: The shaded solder resist

6. Line

6.1 does not allow short circuit or open circuit

Gap allowed 6.2 lines, but should ensure that the notch lines not to reduce the line width is more than 20% of the design, when the width is greater than 3mm, the line or lines a cavity gap width of less than the line of 1/3, and the length of the voids or gaps does not exceed the width of the wire may be acceptable, but such cases on the same board can not be more than two.

Note: The gap ---- pits line the edge of the substrate exposed

6.3 pinhole ratio line, sand and the maximum diameter of the hole width to be less than 1/5, and the same line with no more than three.

6.4 wire width tolerance must not exceed the original design width of ± 20%, but also to ensure that the line spacing should not exceed ± 20% tolerance of the original design values.

6.5 Single-point bulge or sag line does not exceed the original design width of ± 20%.

6.6 Each line metal plate residue does not exceed three, and should make the width or line spacing to increase or decrease by 30% over the original design values.

6.7 linewidth allowed to appear jagged.

6.8 does not allow the line twist.

7. Solder mask (green oil)

Model 7.1 using ink, color, brand and customer must specify ink agreement would, under the requirements of the customer is not specified.

7.2 customers are required to provide the above color model solder the lower limit of the scope of delivery.

7.3 In normal soldering solder mask can not produce blistering finish off.

7.4 Printing the entire surface of the solder mask shall be uniform and consistent color.

Patch 7.5 solder resist film, the same side must not exceed three (100mm2 or more means at the plate surface), and the length is not greater than each of 5mm, the patch should be smooth and uniform color.

7.6 In 3M600 #'s secret tape affixed to the plate surface, 30 seconds later, with the direction of the board into a 900 angle pull, not a green oil off.

7.7 parts solder joints of foot pad area of ​​the membrane can not make the arc intersects the outer pad 900,

Copper solder layer under 8.1 does not allow oxidation, stains, lines burned and so on.

8.2 parts hole solder resist are not allowed into the hole (non-vias parts according to customer needs to see whether the required sealing).

8.3 solder are not allowed lint and other debris across two lines, allowing the length of 1mm or less lint and other non-conductive materials exist, but every square inch can not more than two.

8.4 solder the line thickness not less than 10um.

8.5 solder wave or surface texture has not affected the thickness prescribed limit, between conductors mild wrinkling, but not caused by the void, and good adhesion.

9 metal coating and spray tin layer

9.1 can not have a rough metal coating undesirable phenomena such as electroplating and finger prints marks.

9.2 metal coating with 3M600 # tape test, can not have the coating peeling or blistering stratification.

9.3 Line recessed portion of coating thickness not less than 15 um, and the sunken area of ​​no more than 4mm, no more than two points on each board.

Spray coating and spray tin tin plate thickness 9.4
(1) coating thickness should be greater than 3 um, the thickest not cause small holes.
(2) holes with the average coating thickness of not less than 25 um, the minimum value of not less than 20 um, the maximum value can not lead to a small hole.
(3) HAL layer of smooth and bright, clean pewter surface discoloration.

9.5 Water gold plate coating thickness
The minimum thickness of copper is not smaller than hole 10 um, a nickel plating layer line thickness not less than 5 um, the average thickness of the nickel layer hole.

Not less than 5 um. Gold layer evenly golden appearance, golden color, no oxidation, pollution discoloration.

10.1 In the metal particles within the line forming part of the line may be allowed, but the total area no larger than 3mm2, and shall not be greater than 50% of board edge and line spacing.

10.2 Lu base line is not allowed scratching, scratching lines is not the same side of the substrate exposed not more than 2, and a length of not more than 5mm, but can not exceed the depth of scratches 3 um.

10.3 solder scratch exposed metal layer can not lead, if the scratch width not exceeding 0.05mm, the length of no more than 5mm, in the same block board allows two.

10.4 pairs of panel lines open up lines are not more than three, and can not be on the same side of the plywood allows only two, fill line length can not exceed 3mm, fill line position from the outside pad 1mm, the corner can not make up line.

10.5 line non-stick tin.

No significant 10.6 contouring milling debris, plate edge milling process should be smooth, punching appearance should be neat, no burst board edge defects, the board may not have ink residue, corrosive residue, oil, glue stains, finger prints, perspiration and other pollutants.

11 Goldfinger

11.1 In the solder junction with Goldfinger allows pewter or copper stick to the finger thick, but the width is not more than 0.13mm.

When the nickel layer thickness of not less than 11.2 Goldfinger 5um, when a customer asked Goldfinger thick gold plating and coating thickness is not specified, the gold thickness not less than 0.5 um, thin gold-plated customer requirements but does not specify the thickness of the gold thickness can not be less than 0.05 um.

11.3 Goldfinger can not have oxidation, burning, pollution, glue stains, can not have their spacing residual copper or other foreign matter, the color was golden color.

11.4 Goldfinger edge may not cocked and defects.

11.5 Goldfinger edge gap length not greater than 0.15mm2, and each piece allows only one finger, so each board can not cheat more than two.

11.6 to 3M600 # tape affixed to the finger, after 30 seconds, with a 900 angle with the board's direction pull, can not have gold or nickel off or tilt (ie, gold rejection, rejection of nickel).

11.7 Goldfinger allowed 2mm long, deep scratches 3um less than the two, but not exposed copper, exposed nickel, scratches position is not in 3/5 parts of the middle finger, so that the same piece of finger board can not be more than two.

11.8 Goldfinger pinhole depressions, indentations, holes less than 2:00 (inclusive), but the gap length in 0.15um, and can not be exposed nickel, copper exposure, each board has a number of defects can not be more than two finger one, but not the defects 3/5 in the middle of the finger.

11.9 Goldfinger edge solder mask allows maximum coverage does not exceed 1.5mm (without prejudice to cheat when you use).

12 text symbols

12.1 according to customer requirements checks are single-sided or double-sided character.

12.2 character ink color, model, brand to meet customer requirements.

12.3 coincidence character and integrity should be able to clearly identify lines evenly.

12.4 characters are generally not allowed on the pad or SMD position (unless the customer master figure allowed), shall not enter into the hole.

12.1 check whether the customer requirements in the process of marking text, period, plus the location meets the customer requirements.

12.2 polarity sign, parts symbols, patterns can not be wrong.

12.3 character can not be a ghost or not clearly identified, or because of defects lead to misidentification (such as P, R, D, B).

12.4 with 3M600 # tape affixed to the surface of the characters, after 30 seconds, with a surface perpendicular to the pulling force plates, can not have the character off phenomenon.

13 Mark

13.1 When the customer needs a part or one of the following marks shall be printed on the upper level and location requirements: The company's mark, customer mark, UL mark, date of manufacture, customer part number (P / N), materials and flammable mark.

13.2 mark level (such as lines, solder mask, character, inner, etc.) is correct, complete and clear markers; does not lead to misunderstanding mistake when crippled.

14 dimensions and machining

14.1 boards Dimensions tolerances as follows:

processing methods cheat sheet cheat sheet no tolerance tolerance
Milling ± 0.15mm ± 0.2mm
Red plate ± 0.15mm ± 0.15mm

Dimensions 14.2 Hole tolerance is ± 0.1mm, Hole center distance from the edge of tolerance should be less than ± 0.15mm.

14.3 plate edge: CNC milling shaped plate edges or holes, slots should be smooth, no exposed copper phenomenon; punching processing board edge or shaped holes, slots should be no bursting, defect, no red line injury phenomenon, board edges neat.

14.4 machining tolerances at customers request according to customer requirements.

14.5 hypotenuse plate, angle, length should meet customer requirements, the hypotenuse surface should be smooth, uniform, neat line.

After 14.6 V-CUT, single plate appearance meet the requirements, V-CUT uniform depth. After the V-cut remaining thickness of the public

Difference in the table below:
Thickness (mm) 0.81.01.21.62.02.5 above
V-CUT remaining thickness (mm) 0.2-0.30.2-0.30.3-0.40.4-0.50.5-0.60.5-0.7

When the thickness is less than 0.8mm, a separate agreement with the customer, and the V-CUT not appear exposed copper phenomenon, V-CUT straight line and the width of compliance requirements.

15 Physical Characteristics

15.1 weldability:
(1) 245 ± 50C tin warm, neutral flux, test panels within 3 ± 1 秒 moist, it can not be welded part, may not exceed 5% of the gold plate, and can not be concentrated in one area; tin plate should all run wet.
(2) After the solderability test, solder character should not have blistering, off phenomenon.
(3) can not have a blow hole, blasting holes, can not be separated from the hole wall.
(4) warping board shall comply with the requirements.
(5) substrate without stratification.

15.2 Thermal Shock
Conditions: temperature 288 ± 0C under immersion tin tin three times, each time for 10 seconds after each dip tin to cool to room temperature, immersion tin should not be any of the following three conditions:
(1) There shall be no layered substrate, copper may not have blistering or warped phenomenon.
(2) There shall be no multilayer inner layers.
(3) non-hole plating fracture or delamination.
(4) can not blow holes, blasting holes.

16.1 solder character solvent test
Method prescribed by the Company in the character of the solvent after the solder test, there should not be off, dissolution, swelling, surface
Rough, obvious discoloration.

16.2 sliced
In the case of the method specified in the Company's completion of the test, which should be observed and measured:
(1) hole plating thickness shall comply with the requirements.
(2) hole and the hole wall coating with good no cracks.
(3) multilayer coating and the inner bore of copper with good no cracks.
(4) holes with no damage.
(5) hole uniform coating, the thickness of the hole deviation shall not exceed ± 30%, and the average value should meet the requirements.

16.3 adhesion test
(1) do with 3M600 # tape adhesion test, the gold, nickel, copper plating adhesion is good, no shedding stratification
(2) made with 3M600 # tape adhesion test, the solder, the characters may not have off phenomenon.

Double-sided circuit board layout and system testing

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