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Aluminum substrate production specifications and aluminum substrate production process
2021-10-07
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Author:Aure

Aluminum substrate production specifications and aluminum substrate production process




Aluminum-based circuit board factories will have corresponding aluminum substrate production specifications and aluminum substrate production process guidelines. Aluminum substrate production specifications are the main basis for production preparations and the main technical documents of aluminum substrate manufacturers. The complete aluminum substrate production process guidelines are circuit boards. The manufacturer efficiently implements the practical measures of refined management.

Aluminum PCB (Aluminum PCB) has been widely used in the fields of hybrid integrated circuits, automobiles, office automation, high-power electrical equipment, power supply equipment, etc. in recent years with excellent heat dissipation, mechanical processability, dimensional stability and electrical performance. Aluminum-based copper clad laminates were first invented by Sanyo Co., Ltd. in 1969. my country began to develop and produce in 1988, and began R&D and mass production in 2000. In order to adapt to mass production and stable quality production, this production specification was specially formulated. The mainstream aluminum substrates are more famous. The aluminum substrates mainly look at the thermal conductivity, withstand voltage and thermal resistance values, which are related to the life and life of the aluminum substrate.
Aluminum plate
2. Scope: This production specification introduces and explains the whole production process of aluminum-based copper clad laminates to ensure the smooth production of this board in our company.
3. Process flow:
Cutting → drilling → dry film light imaging → inspection board → etching → corrosion inspection → green oil → character → green inspection → tin spraying → aluminum base surface treatment → punching → final inspection → packaging → shipment
4. Matters needing attention:


Aluminum substrate production specifications and aluminum substrate production process


4.1 The aluminum substrate material is expensive, and special attention should be paid to the standardization of the operation during the production process to prevent the occurrence of scrap due to non-standard operation.
4.2 The operator of each process must handle it gently to avoid scratches on the board surface and aluminum base surface.
4.3 The operators of each process should try to avoid touching the effective area of the aluminum substrate with their hands. When spraying tin and holding the board in the subsequent processes, only hold the edge of the board, and it is strictly forbidden to touch the board directly with the fingers.
4.4 The aluminum base plate is a special board, and its production should arouse the attention of all districts and processes. The section manager and foreman personally check the quality to ensure the smooth production of the board in each process.
5. Specific process flow and special production parameters:
5.1 Cutting
5.1.1 Strengthen incoming material inspection (must use sheet material with protective film on the aluminum surface).
5.1.2 There is no need for baking sheet after cutting.
5.1.3 Handle with care and pay attention to the protection of the aluminum base surface (protective film).
5.2 Drilling
5.2.1 The drilling parameters are the same as the drilling parameters of FR-4 plate.
5.2.2 The tolerance of the aperture is very strict, 4OZ-based Cu pay attention to control the production of the front.
5.2.3 Drill holes with the copper facing upwards.
5.3 Dry film
5.3.1 Incoming material inspection: The aluminum base surface protective film must be inspected before grinding. If it is damaged, it must be fixed with blue glue before pre-treatment.
5.3.2 Grinding plate: Only the copper surface is processed.
5.3.3 Film: Copper surface and aluminum base surface must be filmed.
Control the interval between the grinding plate and the film to be less than 1 minute to ensure the film temperature is stable.
5.3.4 Make a decision: pay attention to the accuracy of the decision.
5.3.5 Exposure: Exposure ruler: 7-9 grids have residual glue.
5.3.6 Development: Pressure: 20~35psi Speed: 2.0~2.6m/min
All operators must be careful to avoid scratches on the protective film and aluminum base surface.
5.4 Inspection board
5.4.1 The line surface must be inspected according to MI requirements.
5.4.2 The aluminum base must also be inspected, and the dry film on the aluminum base must be free from film drop or damage.
5.5 Etching
5.5.1 Since the copper base is generally 4OZ, there will be certain difficulties during etching. The first board must be approved personally by the foreman. The line width and line gap should be spot-checked during the boarding process. The line width should be spot-checked every 10PNL board and recorded.
5.5.2 Recommended parameters: Speed: 7~11dm/min Pressure: 2.5kg/cm2
Specific gravity: 25Be temperature: 55℃
(The above parameters are for reference only, subject to the test board results)
5.5.3 When removing the film, pay attention to the control of the time between 4~6min, because aluminum and NaOH will react, but the film removal must be clean, and the film removal liquid is not allowed to be heated during film removal. For the plate without protective film on the aluminum surface, after it is lifted out of the stripping liquid, the strip should not be able to stay and wash the stripping liquid with water in time to prevent the lye from biting the aluminum surface.
5.6 Corrosion inspection
5.6.1 Check the board normally.
5.6.2 It is strictly forbidden to repair the circuit with a blade, so as not to damage the medium layer.
5.7 Green Oil
5.7.1 Production process:
Grinding plate (only brushing the copper surface) → silk-screen green oil (first time) → pre-baking → silk-screen green oil (second time) → pre-baking → exposure → development → plate grinding machine pickling soft brush → post-curing → next process
5.7.2 Reference parameters:
5.7.2.1 Mesh yarn adopts 36T+100T
5.7.2.2 The first time 75℃×20-30min; the second time 75℃×20-30min
5.7.2.3 Exposure: 60/65 (single side) 9~11 grids
5.7.2.4 Development: Speed: 1.6~1.8m/min Pressure: 3.0kg/m2 (full pressure)
5.7.2.5 Post curing: 90℃×60min+110℃×60min+150℃×60min
The above parameters are using DSR-2200TL ink and are for reference only.
5.7.3 Pay attention to the control of air bubbles during silk screen printing. If necessary, add 1-2% thinner.
5.7.4 Before making a decision, the clapper should check the surface of the board, and ask the foreman if there is a problem before making a decision.
5.8 Spray tin
5.8.1 Before spraying tin, tear off the protective film on the aluminum substrate with protective film before spraying tin.
5.8.2 Hold the edge of the board with both hands, and it is strictly forbidden to touch the board directly with your hands (especially the aluminum base surface).
5.8.3 Pay attention to operation and prevent scratches.
5.8.4 The baking sheet is 130℃, 1 hour before spraying tin, and the interval between baking sheet and tin spraying is less than 10 minutes. In order to avoid stratification and oil loss caused by large temperature differences.
5.8.5 Reworked boards are only allowed to be resprayed once. If there are more than once boards, distinguish them and wait for special treatment.
5.9 Passivation treatment of aluminum base surface
5.9.1 Horizontal passivation line process:
①Grinding plate (500# brush)→②Water washing→③Passivation→④Water washing×3→⑤Blow drying→⑥Drying
Remarks: ①Grinding plate: only grind the aluminum surface, and grind the plate according to FR4 parameters. The first board is required to check the circuit without scratches, black tin surface and other defects, and uniform wear marks.
③Passivation:
Chemical composition Controlled concentration Cylinder volume Cylinder volume Chemical temperature Spray pressure Conveying speed Slot changing frequency
Na2CO3
(CP grade) 50g/l 6500g 130L 40~50℃ 2.0~3.0 1.0~1.5m/min Effective soaking time 10~15S 100m2
K2CrO4
(CP grade) 15g/l 1950g
NaOH
(CP grade) 3g/l 390g
⑥ Drying: 80~90℃ is required.
5.9.2 Matters needing attention:
a. The board member must pay attention to inspection when connecting the board. If it is not polished, you can take it and polish it again. For the polished one, you can use sandpaper (2000#) to smooth it and then take it to polish the board.
b. In the case of discontinuous production, maintenance must be strengthened to ensure clean delivery and clean water tanks.
5.9.3 The foreman must confirm that the aluminum base surface has been processed before the board can flow down.
5.10 Punching board
5.10.1 Hold the edge of the board with both hands, and pay attention to the protection of the aluminum base surface.
5.10.2 The aluminum base plate is formed by high-grade beer die punching, and the punching and the shape are punched at one time or separately. When punching the plate, according to MI requirements, a piece of white paper must be placed on the aluminum surface to punch the plate.
5.10.3 The inspection should be strengthened when punching the board, and be careful not to drop the green oil and scratch the surface of the board.
5.10.4 There is no need to wash the board when the board is out of the final inspection, and the gap between the board and the board is white paper.
5.10.5 The mold should be cleaned with a brush every time the board is punched.
5.11 Final inspection: Perform various inspections in accordance with IPC comprehensive corporate standards.
5.12 Packaging
5.12.1 Boards with different cycles and different material numbers should be packaged separately.
5.12.2 When packaging, separate paper and put moisture-proof beads, and indicate the version number and production cycle (one month is one cycle) after the model number on the smallest packaging label.
6. Regarding the final inspection of the rework method of the scratched and oxidized aluminum substrate
In the final inspection, the aluminum substrates that are oxidized and scratched during the production process should be reworked as follows.
6.1 Aluminum substrate with anodized aluminum surface:
First place the aluminum substrate circuit side up and place it on the desktop, cover the circuit with blue glue and press it tightly, then paste a few double-sided tape on the blue glue, and stick it with a light copper plate, and then press it tightly. You can take it to a deburring plate grinding machine for plate grinding. Note that the pickling must be turned off before grinding the plate and this section of the row wheel must be rinsed with tap water to prevent acid from contaminating the tin surface, or directly put it in the washing section after pickling, with the aluminum base facing up, and only the top grinding Brush and polish the board again if there is oxidation.
Take off the polished plate and place it on the drying section of the plate grinder for drying. It can be placed for 5-10 minutes, or it can be placed on white paper in the tray and brought to the oven for drying. 100.℃×5~10min, be careful not to take it to the forming washer to dry, because the temperature is low, it will cause aluminum surface oxidation.
6.2 Aluminum substrate with polished aluminum surface:
6.2.1 For aluminum substrates with slightly scratched aluminum surface, follow the 6.1 aluminum surface oxidation rework method.
6.2.2 For aluminum substrates with severe scratches on the aluminum surface, first use 2000# sandpaper to smooth the scratches, and then lightly brush them with 4000# sandpaper, and then process the aluminum substrate with 6.2.1 oxidized aluminum surface.
To sum up, as long as aluminum substrate manufacturers have a complete aluminum substrate production process and standardized management implementation, and then implement it into every job position and every work item in the production department, it is a pragmatic measure for circuit board manufacturers to efficiently implement refined management. , Only when standardized management is implemented at all levels, everything is standardized, everyone has something to do, aluminum substrate production has a standard process, and a specific plan for work, can the overall management level of the company be improved, and the company’s execution and production can be improved. Efficiency, improve product quality, and enhance the market competitiveness of PCB circuit board manufacturers.