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Aluminum PCB Stackup

What is Aluminum-based PCB?

Among all MCPCBs,aluminum PCB is one of the most common types.The base material of an aluminum-based PCB consists of an aluminum core and standard FR4,which offers efficient heat dissipation and cools electronic components,thereby improving the overall performance of the product.

Advantages of Aluminum-based PCB

  • Environmental friendly:Aluminum is non-toxic and recyclable. Its production promotes energy conservation and is easy to assemble.Also,using aluminum as the base material for PCBs contributes to environmental protection.

  • Excellent heat dissipation:High temperatures can cause severe damage to electronic devices. Therefore,using materials that facilitate heat dissipation is the right choice.Aluminum effectively transfers heat away from heat-generating components or important parts, minimizing any potentially harmful impact on the circuit board.

  • Durability:Aluminum provides strength, toughness,and durability that ceramic or glass fiber substrates cannot offer.Aluminum is a hard material that reduces the risk of accidental damage during production,handling,and everyday use.

  • Lightweight:Aluminum enhances the strength and resilience of products without adding any significant extra weight.

Structural Features of Aluminum PCB

Circuit Copper Layer:The copper circuit layer (typically using electrolytic copper foil) is etched to form the printed circuit, which is used for component assembly and connections.Compared to traditional FR4,aluminum PCBs can carry higher currents for the same thickness and line width.

Dielectric insulation Layer:The dielectric insulation layer is a core technology of aluminum PCBs, primarily serving the purposes of bonding, insulation, and thermal conduction. A better thermal conductivity of the insulation layer helps in dissipating the heat generated by components. Lower working temperatures of the devices increase power loading, reduce volume, extend lifespan, and enhance power output.

Metal Substrate: The choice of metal for the insulated metal substrate depends on various factors such as thermal expansion coefficient, thermal conductivity, strength, hardness, weight, surface condition, and cost of the metal substrate.

In general, considering cost and technical performance, aluminum substrates are the preferred choice. Available aluminum materials include 6061, 2052, 1060, etc. If there are higher requirements for thermal conductivity, mechanical properties, electrical properties, or other specific performance criteria, copper, stainless steel, iron, or silicon steel plates can also be used.

aluminum pcb.png

Structure type of Aluminum PCB

One-layer aluminum PCB with single component mounting side

One-layer_with_single_side.png

One-layer aluminum PCB with a single component mounting side has the simplest structure and is also the easiest to manufacture. The circuit is directly etched on the copper layer of the aluminum laminate board. 

Heat is transferred from the components to the copper layer,to the PP layer,then to the aluminum layer. 

Two-layer aluminum PCB with single component mounting side

Two-layer_single_side.png

Two-layer aluminum PCB with a single component mounting side has two copper layers and PP layers.

Heat is transferred from the components to the first copper layer, to the first PP layer,to the second copper layer,to the second PP layer and then to the aluminum layer. 

Two-layer aluminum PCB with dual component-mounting sides

Two-layer_two_side.png

When single-sided PCBs are unable to accommodate all the circuitry, aluminum PCBs can be designed as double-sided. The structure of a two-layer aluminum PCB with dual component-mounting sides is similar to that of a two-layer FR4 PCB with dual component-mounting sides. However, the space between PTHs and the aluminum base is filled with resin.

Heat is transferred from the components to the copper layer, then to the PP layer, and finally to the aluminum layer.

Four-layer aluminum PCB with dual component-mounting sides

Four_Layer.png

A four-layer aluminum board has two copper layers and PP layers.

Heat is transferred from the components to the outer copper layer, then to the first PP layer, further to the second copper layer, then to the second PP layer, and finally to the aluminum layer. Therefore, the thermal conductivity of a four-layer PCB is lower than that of a single-layer PCB and a two-layer aluminum PCB with dual component-mounting sides.

Applications

  • Audio Equipment: input amplifier, output amplifier, balanced amplifier, audio amplifier, preamplifier, power amplifier.

  • Power Supply: switch regulator, DC/AC converter, SW regulator, etc.

  • Communication Electronic Devices: high-frequency amplifier, filtering device, transmission circuit.

  • Office Automation Equipment: motor driver, etc.

  • Automobiles: electronic regulator, ignition system, power controller, etc.

  • Computers: CPU board, floppy drive, power supplies, etc.

  • Power Modules: inverter, solid-state relay, rectifier.

  • Lamps and Lighting: With the promotion of energy-saving lamps, various colorful LED energy-saving lamps are highly welcomed in the market, and aluminum PCBs used in LED lamps are being widely used.

Learn how to calculate Aluminum layer thickness(Take 2 layer aluminum PCB as an example)

6bddb0c5-f16e-440e-93fd-a0805c375d35.png

2 layers aluminum PCB substrate, copper thickness 1oz, aluminum base on the bottom of the laminate is probably like this for reference. The above parameters are basically unchanged. The thickness of the aluminum base is the thickness of the plate selected by the customer minus the thicknesses above.

Storage Conditions for Aluminum PCBs

Aluminum PCBs are typically stored in a dark and dry environment. Most aluminum PCBs are prone to moisture absorption, yellowing, and darkening. Generally, they should be used within 48 hours after being unsealed.

Specification of Aluminum Based Copper -Clad Laminate

We currently support aluminum bases from BOYU, CSEM and GDM with thermal conductivity of 1.0~3.0W/m·k.

表格.png

Aluminum PCB Samples Show

By the way:

If we place an order for the wireless circuit of single-sided aluminum substrate, it is best to note whether or not to add thermal conductive glue, otherwise PCBWay will confirm with you whether thermal conductive glue is needed. The thermal conductive glue is milky white. The white part in the picture.

QQ图片20210916164550.png

More information check here:

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Comments (24)
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  • Could you please tell me, what kind of material is the dielectric layer?
    Is it epoxy, polyimid or else?

    PCBWay Team 2024-12-04 10:44:02Reply

    Hello, for the dielectric layer (thermal conductive material layer) of aluminum-based PCBs, we can manufacture materials with thermal conductivity coefficients of 1.0, 1.5, 2.0, 3.0, 5.0, and 8.0.

    Reply
  • I am planning on making a microstrip hairpin bandpass filter. The center frequency is 3.75 GHz and bandwidth is 900 MHz. For dielectric material can i use this aluminum. I used alumina substrate in my simulation design. Is this aluminum the same? If so then can this be used as dielectric material for my filter? Also what is the dielectric constant for this?

    PCBWay Team 2024-11-04 10:08:09Reply

    The alumina you mentioned is used in ceramic boards, not aluminum PCB. The dielectric constant of alumina may be around 10. For aluminum PCBs, our dielectric constant is around 4.60.

    Egan 2024-12-28 06:57:27Reply

    They are not really comparable ... aluminum metal is a conductor, alumina is an insulating ceramic.

    Reply
  • For 2L PCBs since there is a resin block around every via, what is the minimum spacing that vias (Stitching as well) need to follow? Assuming 2oz Copper.

    PCBWay Team 2024-08-28 10:09:34Reply

    The minimum edge-to-edge distance between vias on the same net is 0.2mm, while the minimum distance between vias on different nets is 0.3mm. For densely packed rows of vias, the minimum spacing is 2.4mm.

    Reply
  • With a single layer PCB on the Aluminum substrate can I run the board for over a 1000hrs at 200C?

    PCBWay Team 2024-08-23 09:06:57Reply

    You mentioned that this is quite challenging. 200°C is a relatively high temperature, and prolonged exposure to this temperature could lead to the degradation of the insulation layer, affecting the electrical performance and structural integrity. Additionally, the components on the circuit board also need to withstand the high temperature of 200°C. Most standard components have an operating temperature range between -40°C and 125°C, and exceeding this range could result in component failure.

    Reply
  • On 2L MCPCB (alu, single sided), is it possible to have filled via's? The components need the best possible thermal connection with alu back, a filled via (within it's solder pads) should help. If not possible, via's near the pads will be the next best thing. Via hole size = 0.2mm

    PCBWay Team 2024-04-01 15:17:45Reply

    Are you asking if it's possible to have filled vias on a single-sided 2L MCPCB? If you're considering filled vias for your MCPCB, we recommend opting for a double-sided 2L MCPCB instead.

    Reply
  • On your 2L MCPCB, what is the min hole side on the FR4 part that does not go through aluminum? This is only between two copper layers.

    happy 2023-01-13 15:35:18Reply

    0.15MM

    Reply
  • What is the maximum PCB temperature for a 1-layer aluminium PCB? What is the maximum temperature allowed for the tracks? Best thanks

    Ning 2022-12-05 11:02:18Reply

    Maximum temperature 260 degrees Celsius

    Ning 2022-12-05 11:05:00Reply

    Next time, if you have any questions, you can directly consult your customer representative, and they will reply within 24 hours

    Reply
  • What is the dielectric strength of the through hole in the two layers of aluminum board?

    PCBWay Team 2022-07-28 14:11:02Reply

    DC1500V

    Reply
  • アルミ基板2層でのスルーホールの絶縁耐圧は何Vですか?

    PCBWay Team 2022-07-28 14:11:13Reply

    DC1500V

    Reply
  • May I know what material you use on thermal isolation/prepegs?

    happy 2022-05-30 11:00:18Reply

    PP = FR4, Rogers 4350B or RO4450B https://www.pcbway.com/pcb_prototype/Cost_cores_Foil___Prepreg_for_PCBs.html

    Reply