Aluminum PCB Production Process and Specifications
Posted: May 14, 2022
By: Bonnie
Aluminum PCB has been widely used in hybrid integrated circuits, automobiles, office automation, high-power electrical equipment, power supply equipment and other fields in recent years with excellent heat dissipation, machinability, dimensional stability, and electrical properties. Aluminum substrate is mainly to see the thermal conductivity, voltage value and thermal resistance value, it is related to the life and life of aluminum substrate.
2.2 It must be handled gently during operation to avoid scratches on the board surface and aluminum base surface.
2.3 Try to avoid touching the effective area of the aluminum substrate with your hands as much as possible. Only the edge of the board should be allowed when holding the board during tin spraying and subsequent processes. It is strictly forbidden to directly touch the board with fingers.
2.4 Aluminum substrate is a special plate, and its production should be paid great attention.
3.1.1 Strengthen the incoming inspection (the sheet with protective film on the aluminum surface must be used).
3.1.2 No baking plate is required after opening.
3.2.2 The aperture tolerance is extremely tight. The copper base of 4OZ needs to pay attention to controlling the generation of wave peaks.
3.3.1 Incoming inspection: Before grinding the board, the aluminum base surface protective film must be inspected. If it is damaged, it must be pasted with blue glue before pretreatment.
3.3.2 Milling: only the copper surface is processed.
3.3.3 Filming: Both copper surface and aluminum base surface must be filmed.
Control the time between the grinding plate and the film to be less than 1 minute to ensure that the film temperature is stable.
3.3.4 Clapper: Pay attention to the accuracy of the clapper.
3.3.5 Exposure: Exposure rule: 7 to 9 grids have residual glue.
3.3.6 Development: Pressure: 20 ~ 35psi, Speed: 2.0 ~ 2.6m / min
3.4.1 The circuit surface must check each content according to MI requirements.
3.5.1 Because the copper base is generally 4OZ, there will be some difficulties during etching. The first board must be approved by the foreman before it can be used as a board. Spot checks on line width and line gap should be strengthened in the board. The line width should be checked every 10PNL board and recorded.
3.5.2 Recommended parameters: Speed: 7 ~ 11dm / min Pressure: 2.5kg / cm2
Specific gravity: 25Be Temperature: 55 ° C
(The above parameters are for reference only, subject to test results)
3.6.1 Normal inspection board.
3.7.1 Production Process:
Grinding (only brush the copper surface) → Silkscreen green oil (first time) → Pre-baking → Silkscreen green oil (second time) → Pre-baking → Exposure → Development → Milling machine pickling soft brush → Post-curing → Next process
3.7.2 Reference parameters:
3.7.2.1 Net yarn adopts 36T + 100T
3.7.2.2 The first 75 ℃ × 20-30min; the second 75 ℃ × 20-30min
3.7.2.3 Exposure: 60/65 (single-sided) 9 ~ 11 frames
3.7.2.4 Development: Speed: 1.6 ~ 1.8m / min Pressure: 3.0kg / m2 (full pressure)
3.7.2.5 Post-cure: 90 ℃ × 60min + 110 ℃ × 60min + 150 ℃ × 60min
The above parameters are for DSR-2200TL ink, and are for reference only.
3.7.3 Pay attention to the control of air bubbles during screen printing. If necessary, add 1-2% thinner.
3.8.1 Before spraying tin, remove the protective film from the aluminum substrate with protective film before spraying tin.
3.8.2 Hold the edge of the board with both hands. It is strictly forbidden to touch the board directly with your hands (especially the aluminum base surface).
3.8.3 Pay attention to operation and prevent scratches.
3.8.4 Before baking tin, baking sheet is 130 ° C, 1 hour, and the interval from baking sheet to tin spraying is less than 10 minutes. In order to avoid large temperature differences caused by stratification and oil.
3.9.1 Horizontal passivation line process:
① Grinding plate (500 # brush) → ② water washing → ③ passivation → ④ water washing × 3 → ⑤ blow drying → ⑥ drying
Remarks:
① Grinding plate: Grind only the aluminum surface, and grind the plate according to the FR4 parameter. The first board is required to check that the circuit is not scratched, the tin surface is black and other defects, and the wear marks are uniform.
⑥ Drying: 80 ~ 90 ℃ is required.
3.9.2 Notes:
a. The boarder must pay attention to check when picking up the board. For those who have not been polished, they can be polished again. For those who are scratched, they can be sanded out with sandpaper (2000 #) and then polished.
b. In the case of discontinuous production, maintenance must be strengthened to ensure clean transportation and clean water tanks.
3.9.3 Only after the foreman confirms that the aluminum base surface has been processed, the board can flow down.
3.10 Punches
3.10.1 Hold both sides of the board, pay attention to the protection of the aluminum base surface.
3.10.2 The aluminum substrate is formed with a high-grade beer mold punching plate, and the punching and punching are punched once or separately. When punching the punching plate, a white paper must be placed on the aluminum surface after punching.
3.10.3 When punching the board, the inspection should be strengthened, taking care not to drop green oil and rub the board surface.
3.10.4 There is no need to wash the board at the time of final inspection, and the gap between the board and the board is white paper.
3.10.5 The brush for cleaning the mold should be cleaned once for each punch.
3.11 Final inspection: Various inspections are carried out according to the IPC comprehensive enterprise standard.
3.12 Packaging
3.12.1 The boards with different periods and different material numbers shall be classified and packed.
3.12.2 When packing, separate paper and place moisture-proof beads, and indicate the version number, production cycle (one month is a cycle), etc. after the model number on the smallest package label.
4. About the rework method of the aluminum substrate for final inspection of rubbing and oxidation
The final inspection department, such as the aluminum substrate that caused oxidation and scratches during the production process, reworked as follows.
4.1 Aluminum substrate with aluminum oxide:
First place the aluminum substrate circuit side up and discharge it on the desktop, cover the circuit with blue glue and squeeze it, then paste a few double-sided tape on the blue glue, and stick it with a light copper plate. You can get a deburring mill to grind it. Note that you must turn off the pickling before grinding the plate and rinse this section of the wheel with tap water to prevent the acid from contaminating the tin surface, or directly put it from the washed section after pickling, with the aluminum base facing up, and only grinding on the top Brush, if the board has oxidation phenomenon, you can grind it again.
After grinding the single sheet of the board, remove the single sheet and place it on the drying section of the plate mill for drying. It can be placed for 5 ~ 10min, or it can be placed on the white paper in the tray and dried in the oven. ， 100. ℃ × 5 ~ 10min, be careful not to get the drying machine to dry, because its temperature is low, it will bring aluminum surface oxidation.
4.2 Aluminum substrate with polished aluminum surface:
4.2.1 Aluminum substrate with slightly scratched aluminum surface, according to 6.1 aluminum surface oxidation rework method.
4.2.2 For aluminum substrate with severely scratched aluminum surface, first brush the rubbed area with 2000 # sandpaper, then brush it again with 4000 # sandpaper, and then reprocess according to 4.2.1 aluminum substrate with oxidized aluminum substrate.
5. Repair of aluminum substrate circuit board
Knowing the fault condition first, and setting the fault judgment to a smaller range is conducive to the maintenance work. Therefore, understanding the fault condition of the circuit board is very important to start the repair.
5.1. Board Observation: This is a preliminary study. The purpose is to understand what input and output interfaces the board has, what functions the board implements, and the distribution of various control parts of the board.
5.2. Circuit test: After completing the fault understanding and board observation, according to the actual situation, carry out preliminary inspection on the board. The circuit test may not find the fault point of the board, but experienced circuit board maintenance personnel can Examine a wide range of faults through inspection to pave the way for subsequent repairs.
5.3. Component inspection: Most of the inspection of components requires removing the components from the circuit board with a soldering iron, and then testing with professional equipment. This process will damage the external integrity of the circuit board, so under normal circumstances Maintenance personnel will not disassemble components at will.
5.4. Fault maintenance: through line testing, component testing, etc. to deal with the found faults, including line repair, component replacement, transformation and other work.
1. Aluminum PCB process flow:
2. Note:
2.2 It must be handled gently during operation to avoid scratches on the board surface and aluminum base surface.
2.3 Try to avoid touching the effective area of the aluminum substrate with your hands as much as possible. Only the edge of the board should be allowed when holding the board during tin spraying and subsequent processes. It is strictly forbidden to directly touch the board with fingers.
2.4 Aluminum substrate is a special plate, and its production should be paid great attention.
3.Specific production process and special production parameters:
3.1.1 Strengthen the incoming inspection (the sheet with protective film on the aluminum surface must be used).
3.1.2 No baking plate is required after opening.
3.1.3 Handle gently, pay attention to the protection of the aluminum base surface (protective film).
3.2 Drilling
3.2.1 The drilling parameters are the same as those of FR-4.3.2.2 The aperture tolerance is extremely tight. The copper base of 4OZ needs to pay attention to controlling the generation of wave peaks.
3.2.3 Drill holes with the copper skin facing up.
3.3.1 Incoming inspection: Before grinding the board, the aluminum base surface protective film must be inspected. If it is damaged, it must be pasted with blue glue before pretreatment.
3.3.2 Milling: only the copper surface is processed.
3.3.3 Filming: Both copper surface and aluminum base surface must be filmed.
Control the time between the grinding plate and the film to be less than 1 minute to ensure that the film temperature is stable.
3.3.4 Clapper: Pay attention to the accuracy of the clapper.
3.3.5 Exposure: Exposure rule: 7 to 9 grids have residual glue.
3.3.6 Development: Pressure: 20 ~ 35psi, Speed: 2.0 ~ 2.6m / min
Each operator must be careful to avoid scratches on the protective film and aluminum substrate.
3.4.1 The circuit surface must check each content according to MI requirements.
3.4.2 The aluminum base surface must also be inspected. The dry film on the aluminum base surface must not have film falling and damage.
3.5.1 Because the copper base is generally 4OZ, there will be some difficulties during etching. The first board must be approved by the foreman before it can be used as a board. Spot checks on line width and line gap should be strengthened in the board. The line width should be checked every 10PNL board and recorded.
3.5.2 Recommended parameters: Speed: 7 ~ 11dm / min Pressure: 2.5kg / cm2
Specific gravity: 25Be Temperature: 55 ° C
(The above parameters are for reference only, subject to test results)
3.5.3 When removing the film, pay attention to the time control between 4 ~ 6min, because aluminum and NaOH will react, but it must also ensure that the film is clean, and the film is not allowed to warm up during the film. After the board with no protective film on the aluminum surface is raised from the film release liquid, if the board cannot stay in time, the film release liquid on the plate needs to be washed with water to prevent the alkaline liquid from biting the aluminum surface.
3.6.1 Normal inspection board.
3.6.2 It is strictly forbidden to repair the circuit with a blade, so as not to damage the dielectric layer.
3.7.1 Production Process:
Grinding (only brush the copper surface) → Silkscreen green oil (first time) → Pre-baking → Silkscreen green oil (second time) → Pre-baking → Exposure → Development → Milling machine pickling soft brush → Post-curing → Next process
3.7.2 Reference parameters:
3.7.2.1 Net yarn adopts 36T + 100T
3.7.2.2 The first 75 ℃ × 20-30min; the second 75 ℃ × 20-30min
3.7.2.3 Exposure: 60/65 (single-sided) 9 ~ 11 frames
3.7.2.4 Development: Speed: 1.6 ~ 1.8m / min Pressure: 3.0kg / m2 (full pressure)
3.7.2.5 Post-cure: 90 ℃ × 60min + 110 ℃ × 60min + 150 ℃ × 60min
The above parameters are for DSR-2200TL ink, and are for reference only.
3.7.3 Pay attention to the control of air bubbles during screen printing. If necessary, add 1-2% thinner.
3.7.4 The clapper should check the surface before the clapper. If there is any problem, please ask the foreman to make the clapper.
3.8.1 Before spraying tin, remove the protective film from the aluminum substrate with protective film before spraying tin.
3.8.2 Hold the edge of the board with both hands. It is strictly forbidden to touch the board directly with your hands (especially the aluminum base surface).
3.8.3 Pay attention to operation and prevent scratches.
3.8.4 Before baking tin, baking sheet is 130 ° C, 1 hour, and the interval from baking sheet to tin spraying is less than 10 minutes. In order to avoid large temperature differences caused by stratification and oil.
3.8.5 Rework board is only allowed to be re-sprayed once. If there is more than one board, it should be distinguished for special treatment.
3.9.1 Horizontal passivation line process:
① Grinding plate (500 # brush) → ② water washing → ③ passivation → ④ water washing × 3 → ⑤ blow drying → ⑥ drying
Remarks:
① Grinding plate: Grind only the aluminum surface, and grind the plate according to the FR4 parameter. The first board is required to check that the circuit is not scratched, the tin surface is black and other defects, and the wear marks are uniform.
⑥ Drying: 80 ~ 90 ℃ is required.
3.9.2 Notes:
a. The boarder must pay attention to check when picking up the board. For those who have not been polished, they can be polished again. For those who are scratched, they can be sanded out with sandpaper (2000 #) and then polished.
b. In the case of discontinuous production, maintenance must be strengthened to ensure clean transportation and clean water tanks.
3.9.3 Only after the foreman confirms that the aluminum base surface has been processed, the board can flow down.
3.10 Punches
3.10.1 Hold both sides of the board, pay attention to the protection of the aluminum base surface.
3.10.2 The aluminum substrate is formed with a high-grade beer mold punching plate, and the punching and punching are punched once or separately. When punching the punching plate, a white paper must be placed on the aluminum surface after punching.
3.10.3 When punching the board, the inspection should be strengthened, taking care not to drop green oil and rub the board surface.
3.10.4 There is no need to wash the board at the time of final inspection, and the gap between the board and the board is white paper.
3.10.5 The brush for cleaning the mold should be cleaned once for each punch.
3.11 Final inspection: Various inspections are carried out according to the IPC comprehensive enterprise standard.
3.12 Packaging
3.12.1 The boards with different periods and different material numbers shall be classified and packed.
3.12.2 When packing, separate paper and place moisture-proof beads, and indicate the version number, production cycle (one month is a cycle), etc. after the model number on the smallest package label.
4. About the rework method of the aluminum substrate for final inspection of rubbing and oxidation
The final inspection department, such as the aluminum substrate that caused oxidation and scratches during the production process, reworked as follows.
4.1 Aluminum substrate with aluminum oxide:
First place the aluminum substrate circuit side up and discharge it on the desktop, cover the circuit with blue glue and squeeze it, then paste a few double-sided tape on the blue glue, and stick it with a light copper plate. You can get a deburring mill to grind it. Note that you must turn off the pickling before grinding the plate and rinse this section of the wheel with tap water to prevent the acid from contaminating the tin surface, or directly put it from the washed section after pickling, with the aluminum base facing up, and only grinding on the top Brush, if the board has oxidation phenomenon, you can grind it again.
After grinding the single sheet of the board, remove the single sheet and place it on the drying section of the plate mill for drying. It can be placed for 5 ~ 10min, or it can be placed on the white paper in the tray and dried in the oven. ， 100. ℃ × 5 ~ 10min, be careful not to get the drying machine to dry, because its temperature is low, it will bring aluminum surface oxidation.
4.2 Aluminum substrate with polished aluminum surface:
4.2.1 Aluminum substrate with slightly scratched aluminum surface, according to 6.1 aluminum surface oxidation rework method.
4.2.2 For aluminum substrate with severely scratched aluminum surface, first brush the rubbed area with 2000 # sandpaper, then brush it again with 4000 # sandpaper, and then reprocess according to 4.2.1 aluminum substrate with oxidized aluminum substrate.
5. Repair of aluminum substrate circuit board
Knowing the fault condition first, and setting the fault judgment to a smaller range is conducive to the maintenance work. Therefore, understanding the fault condition of the circuit board is very important to start the repair.
5.1. Board Observation: This is a preliminary study. The purpose is to understand what input and output interfaces the board has, what functions the board implements, and the distribution of various control parts of the board.
5.2. Circuit test: After completing the fault understanding and board observation, according to the actual situation, carry out preliminary inspection on the board. The circuit test may not find the fault point of the board, but experienced circuit board maintenance personnel can Examine a wide range of faults through inspection to pave the way for subsequent repairs.
5.3. Component inspection: Most of the inspection of components requires removing the components from the circuit board with a soldering iron, and then testing with professional equipment. This process will damage the external integrity of the circuit board, so under normal circumstances Maintenance personnel will not disassemble components at will.
5.4. Fault maintenance: through line testing, component testing, etc. to deal with the found faults, including line repair, component replacement, transformation and other work.
5.5. On-machine test: The board that has completed the maintenance work needs to be tested again. After it is determined that there is no fault, it can be tested on the machine.
More resources:
Do you have any questions about the above-mentioned? Contact us now, we will reply to you soon.
Is the article useful to you?
No
Yes(
8
)
8
558
1
Share to: