IC carrier plate product manufacturing process capable of controllably improving gray-scale value of gold surface

Abstract

The invention relates to a manufacturing process of an IC (integrated circuit) carrier plate product with controllably improved gray-scale value of a gold surface. The manufacturing process comprises the following steps: step 1, pre-working procedure; step 2, polishing; step 3, DF automatic film pressing; 4, exposing, developing and etching; step 5, scanning and checking; step 6, WF pretreatment; step 7, printing oil; step 8, curing and developing; 9, nickel, palladium and gold deposition pretreatment; and step 10, nickel, palladium and gold deposition. A polishing and grinding process is added before circuit manufacturing, a unique composite micro-etching process is adopted in resistance welding pretreatment, and a unique physical sputtering and chemical micro-etching process is adopted in nickel-palladium-gold deposition pretreatment, so that the copper surface Ra can be accurately controlled, the gray-scale value of the gold surface and the reflection uniformity of the gold surface are effectively improved, the fluctuation of the gray-scale value is reduced, and the service life of the circuit is prolonged. The AVI can perform normal scanning identification; the method is high in practicability and has high popularization significance.

Description

Technical Field

[0001] This invention relates to the field of circuit board manufacturing processes, and in particular to a manufacturing process for IC substrate products with controllable improvement of gold-plated grayscale values. Background Technology

[0002] In IC substrate production, controlling the grayscale value of the gold surface (usually the gold fingers or soldering areas) is a critical step in ensuring product quality and reliability. The core purpose of controlling the grayscale value of the gold surface is to accurately monitor and ensure the consistency of the thickness, density, and chemical composition of the gold plating, thereby ensuring the yield and long-term reliability of subsequent chip packaging (such as wire bonding and flip chip bonding).

[0003] However, in traditional processes, the grayscale value of the gold surface is often difficult to control, resulting in excessive fluctuations. Especially after solder mask pretreatment, the Ra value of the copper surface is often too high and difficult to control, which can lead to an increase in the Ra value of the gold surface after subsequent nickel-palladium-gold plating, ultimately resulting in an excessively low grayscale value. A low overall grayscale value on the gold surface can also lead to poor uniformity of reflectivity and problems with AVI (automatic vision inspection) scanning and recognition, ultimately affecting the overall yield of the IC substrate. Summary of the Invention

[0004] Therefore, it is necessary to provide a manufacturing process for IC substrate products that allows for controllable improvement of the gold surface grayscale value, addressing the shortcomings of existing technologies.

[0005] A manufacturing process for IC substrate products with controllable improvement of gold-plated grayscale values ​​includes the following steps:

[0006] Step 1: Pre-processing, cut the substrate to the appropriate size according to production requirements, lay base copper on the substrate surface and clean it.

[0007] Step 2: Polishing. A combination of ceramic abrasive and non-woven fabric is used to polish the base copper of the substrate, so that the surface Ra of the base copper is less than 0.1μm.

[0008] Step 3: DF (dry film) automatic lamination. The base copper surface is micro-etched and acid-washed to roughen its surface, increase the specific surface area, and ensure the adhesion effect of the copper surface. Then, the dry film is attached to the base copper surface using an automatic lamination machine.

[0009] Step 4: Exposure, development, and etching. Using a high-precision laser, the exposed circuit pattern is scanned on the dry film. A weak alkaline solution is used to dissolve the dry film that has not been exposed by the laser, exposing the copper underneath. Then, an etching solution is used to etch away the exposed copper, while the copper in the circuit area protected by the dry film is retained to form the circuit copper. Finally, a strong alkaline solution is used to completely peel off the dry film protecting the circuit copper.

[0010] Step 5: Scan and inspect. Use a high-resolution camera to automatically scan the board surface, compare the etched board circuit with the original design, check for possible defects in the etched circuit pattern, and use X-ray to scan the internal structure of the circuit board to check the quality of the copper plating inside the holes and the alignment accuracy of the interlayer holes.

[0011] Step 6: WF (wet film) pretreatment. Before solder masking, the copper surface of the circuit is micro-etched. A composite micro-etching process is used to control the Ra of the copper surface of the circuit to 0.3-0.4μm.

[0012] Step 7: Printing Ink. Apply solder resist ink evenly to the board surface by screen printing or spraying. After printing, use a settling and air knife process to make the wet solder resist ink flow more evenly and smooth, eliminating uneven thickness and streaks caused by printing.

[0013] Step 8: Curing and developing. Use an ultraviolet light source to irradiate the solder resist ink, causing the ink in the areas that need to be cured to undergo a polymerization reaction and initially cure. After UV exposure and curing, use a weak alkaline solution to rinse the board surface to dissolve the unexposed solder resist ink, thereby exposing the pads and holes that need to be soldered. Place the developed board in an oven and bake it for several hours under a specific high temperature curve to allow the solder resist ink to fully polymerize and cure, achieving the final mechanical strength, electrical properties and chemical stability.

[0014] Step 9: Pretreatment for immersion nickel-palladium-gold plating. Select diamond abrasive particles and use physical sputtering to sputter the diamond abrasive onto the surface of the pads and holes to create a polishing effect. Then, use chemical agents to perform chemical micro-etching on the surface of the pads and holes to further reduce the Ra of the copper surface to 0.2-0.28μm.

[0015] Step 10: Immersion nickel-palladium-gold plating. Through a chemical plating reaction, nickel, palladium, and gold layers are deposited on the surface of the pads and vias to protect the pads and vias from oxidation and improve the soldering and electrical connection of the pads.

[0016] Furthermore, in step 2, the polishing specification is 3000 mesh, and the selected ceramic abrasive has a particle size of 5μm.

[0017] Furthermore, in step 6, the composite micro-etching process uses sulfuric acid and hydrogen peroxide to micro-etch the circuit copper, with the micro-etching amount controlled within the range of 0.8-0.9 μm, and uses formic acid to coarsen the circuit copper.

[0018] Furthermore, in step 6, the sulfuric acid content in the sulfuric acid-hydrogen peroxide agent is 10%-15%, the hydrogen peroxide content is less than 8%, and the formic acid content in the formic acid agent is 5%-10%.

[0019] Furthermore, in step 9, the physical sputtering grinding specification is 400 grit, the physical sputtering angle is 55°-65°, and the sputtering pressure is 1.6-1.8 kg / cm². 2 .

[0020] Furthermore, in step 9, the chemical micro-etching uses sulfuric acid and hydrogen peroxide to micro-etch the pads and holes, wherein the sulfuric acid content in the sulfuric acid and hydrogen peroxide is 24% and the hydrogen peroxide content is 15%, and the micro-etching amount is controlled within the range of 1.5-2.0 μm.

[0021] In summary, the beneficial effects of the IC substrate manufacturing process for controllable improvement of gold surface grayscale value of the present invention are as follows: by adding a polishing and grinding process before circuit fabrication, using a unique composite micro-etching process before solder mask pretreatment, and using a unique physical sputtering and chemical micro-etching process before nickel-palladium-gold plating pretreatment, the Ra of the copper surface can be precisely controlled, thereby effectively improving the grayscale value and reflectivity of the gold surface, reducing grayscale value fluctuations, and enabling AVI to scan and recognize normally. The present invention is highly practical and has strong promotional significance. Detailed Implementation

[0022] To further understand the features, technical means, and specific objectives and functions of the present invention, and to analyze the advantages and spirit of the present invention, the following detailed description of the present invention will provide a further understanding.

[0023] This invention provides a manufacturing process for IC substrate products with controllable improvement of gold-plated grayscale values, comprising the following steps:

[0024] Step 1: Pre-processing, cut the substrate to the appropriate size according to production requirements, lay base copper on the substrate surface and clean it.

[0025] Step 2: Polishing. Design a polishing specification of 3000 grit, select ceramic abrasive with a particle size of 5μm, and use an integrated combination process of ceramic abrasive and non-woven fabric to polish the base copper of the substrate so that the surface Ra of the base copper is less than 0.1μm.

[0026] Step 3: DF (dry film) automatic lamination. The base copper surface is micro-etched and acid-washed to roughen its surface, increase the specific surface area, and ensure the adhesion effect of the copper surface. Then, the dry film is attached to the base copper surface using an automatic lamination machine.

[0027] Step 4: Exposure, development, and etching. Using a high-precision laser, the exposed circuit pattern is scanned on the dry film. A weak alkaline solution is used to dissolve the dry film that has not been exposed by the laser, exposing the copper underneath. Then, an etching solution is used to etch away the exposed copper, while the copper in the circuit area protected by the dry film is retained to form the circuit copper. Finally, a strong alkaline solution is used to completely peel off the dry film protecting the circuit copper.

[0028] Step 5: Scan and inspect. Use a high-resolution camera to automatically scan the board surface, compare the etched board circuit with the original design, check for possible defects in the etched circuit pattern, and use X-ray to scan the internal structure of the circuit board to check the quality of the copper plating inside the holes and the alignment accuracy of the interlayer holes.

[0029] Step 6: WF (Wet Film) pretreatment. Before solder masking, the copper surface of the circuit is micro-etched. A composite micro-etching process using sulfuric acid and hydrogen peroxide agents and formic acid agents to coarsen the surface Ra of the copper circuit is controlled at 0.3-0.4μm. The sulfuric acid content in the sulfuric acid and hydrogen peroxide agents is 10%-15%, the hydrogen peroxide content is less than 8%, the micro-etching amount is controlled in the range of 0.8-0.9μm, and the formic acid content in the formic acid agents is 5%-10%.

[0030] Step 7: Printing Ink. Apply solder resist ink evenly to the board surface by screen printing or spraying. After printing, use a settling and air knife process to make the wet solder resist ink flow more evenly and smooth, eliminating uneven thickness and streaks caused by printing.

[0031] Step 8: Curing and developing. Use an ultraviolet light source to irradiate the solder resist ink, causing the ink in the areas that need to be cured to undergo a polymerization reaction and initially cure. After UV exposure and curing, use a weak alkaline solution to rinse the board surface to dissolve the unexposed solder resist ink, thereby exposing the pads and holes that need to be soldered. Place the developed board in an oven and bake it for several hours under a specific high temperature curve to allow the solder resist ink to fully polymerize and cure, achieving the final mechanical strength, electrical properties and chemical stability.

[0032] Step 9: Pre-treatment for immersion nickel-palladium-gold plating. Design a 400-grit physical sputtering polishing specification, using diamond abrasive particles. Utilize physical sputtering to apply the diamond abrasive to the surfaces of the pads and vias to create a polishing effect. The sputtering angle is set to 55°-65°, and the sputtering pressure is set to 1.6-1.8 kg / cm². 2 Then, sulfuric acid and hydrogen peroxide were used to chemically etch the surface of the pads and holes to further reduce the Ra of the copper surface to 0.2-0.28μm. The sulfuric acid content in the sulfuric acid and hydrogen peroxide was 24%, the hydrogen peroxide content was 15%, and the amount of micro-etching was controlled within the range of 1.5-2.0μm.

[0033] Step 10: Immersion nickel-palladium-gold plating. Through a chemical plating reaction, nickel, palladium, and gold layers are deposited on the surface of the pads and vias to protect the pads and vias from oxidation and improve the soldering and electrical connection of the pads.

[0034] Specifically, in this embodiment, a corresponding grayscale value prediction model has been developed. The model algorithm is: GS = 49.8 + 92μ1 + 188.4μ2 - 184.2μ1μ2, where GS is the grayscale value, μ1 is the amount of micro-etching before solder resist treatment, and μ2 is the amount of micro-etching before immersion nickel-palladium-gold plating treatment. Based on this prediction model, by simply adjusting the amount of micro-etching before solder resist treatment and the amount of micro-etching before immersion nickel-palladium-gold plating treatment, the grayscale value can be controlled within ±5% accuracy.

[0035] In summary, the beneficial effects of the IC substrate manufacturing process for controllable improvement of gold surface grayscale value of the present invention are as follows: by adding a polishing and grinding process before circuit fabrication, using a unique composite micro-etching process before solder mask pretreatment, and using a unique physical sputtering and chemical micro-etching process before nickel-palladium-gold plating pretreatment, the Ra of the copper surface can be precisely controlled, thereby effectively improving the grayscale value and reflectivity of the gold surface, reducing grayscale value fluctuations, and enabling AVI to scan and recognize normally. The present invention is highly practical and has strong promotional significance.

[0036] The embodiments described above illustrate only one implementation of the invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of the invention. Therefore, the scope of protection of the invention patent should be determined by the appended claims.

Claims

1. A manufacturing process for IC substrate products with controllable improvement of gold-plated grayscale values, characterized in that, Includes the following steps: Step 1: Pre-processing, cut the substrate to the appropriate size according to production requirements, lay base copper on the substrate surface and clean it. Step 2: Polishing. A combination of ceramic abrasive and non-woven fabric is used to polish the base copper of the substrate, so that the surface Ra of the base copper is less than 0.1μm. Step 3: DF (dry film) automatic lamination. The base copper surface is micro-etched and acid-washed to roughen its surface, increase the specific surface area, and ensure the adhesion effect of the copper surface. Then, the dry film is attached to the base copper surface using an automatic lamination machine. Step 4: Exposure, development, and etching. Using a high-precision laser, the exposed circuit pattern is scanned on the dry film. A weak alkaline solution is used to dissolve the dry film that has not been exposed by the laser, exposing the copper underneath. Then, an etching solution is used to etch away the exposed copper, while the copper in the circuit area protected by the dry film is retained to form the circuit copper. Finally, a strong alkaline solution is used to completely peel off the dry film protecting the circuit copper. Step 5: Scan and inspect. Use a high-resolution camera to automatically scan the board surface, compare the etched board circuit with the original design, check for possible defects in the etched circuit pattern, and use X-ray to scan the internal structure of the circuit board to check the quality of the copper plating inside the holes and the alignment accuracy of the interlayer holes. Step 6: WF (wet film) pretreatment. Before solder masking, the copper surface of the circuit is micro-etched. A composite micro-etching process is used to control the Ra of the copper surface of the circuit to 0.3-0.4μm. Step 7: Printing Ink. Apply solder resist ink evenly to the board surface by screen printing or spraying. After printing, use a settling and air knife process to make the wet solder resist ink flow more evenly and smooth, eliminating uneven thickness and streaks caused by printing. Step 8: Curing and developing. Use an ultraviolet light source to irradiate the solder resist ink, causing the ink in the areas that need to be cured to undergo a polymerization reaction and initially cure. After UV exposure and curing, use a weak alkaline solution to rinse the board surface to dissolve the unexposed solder resist ink, thereby exposing the pads and holes that need to be soldered. Place the developed board in an oven and bake it for several hours under a specific high temperature curve to allow the solder resist ink to fully polymerize and cure, achieving the final mechanical strength, electrical properties and chemical stability. Step 9: Pretreatment for immersion nickel-palladium-gold plating. Select diamond abrasive particles and use physical sputtering to sputter the diamond abrasive onto the surface of the pads and holes to create a polishing effect. Then, use chemical agents to perform chemical micro-etching on the surface of the pads and holes to further reduce the Ra of the copper surface to 0.2-0.28μm. Step 10: Immersion nickel-palladium-gold plating. Through a chemical plating reaction, nickel, palladium, and gold layers are deposited on the surface of the pads and vias to protect the pads and vias from oxidation and improve the soldering and electrical connection of the pads.

2. The IC substrate product manufacturing process with controllable improvement of gold-plated grayscale value as described in claim 1, characterized in that: In step 2, the polishing specification is 3000 mesh, and the selected ceramic abrasive has a particle size of 5μm.

3. The IC substrate product manufacturing process with controllable improvement of gold-plated grayscale value as described in claim 1, characterized in that: In step 6, the composite micro-etching process uses sulfuric acid and hydrogen peroxide to micro-etch the circuit copper, with the micro-etching amount controlled within the range of 0.8-0.9 μm, and uses formic acid to coarsen the circuit copper.

4. The IC substrate product manufacturing process with controllable improvement of gold-plated grayscale value as described in claim 3, characterized in that: In step 6, the sulfuric acid and hydrogen peroxide reagent contains 10%-15% sulfuric acid and less than 8% hydrogen peroxide, and the formic acid reagent contains 5%-10% formic acid.

5. The IC substrate product manufacturing process with controllable improvement of gold-plated grayscale value as described in claim 1, characterized in that: In step 9, the physical sputtering grinding specification is 400 grit, the physical sputtering angle is 55°-65°, and the sputtering pressure is 1.6-1.8 kg / cm². 2 .

6. The IC substrate product manufacturing process with controllable improvement of gold-plated grayscale value as described in claim 1, characterized in that: In step 9, chemical micro-etching is performed on the pads and vias using a sulfuric acid and hydrogen peroxide solution. The sulfuric acid and hydrogen peroxide solution contains 24% sulfuric acid and 15% hydrogen peroxide, and the micro-etching depth is controlled within the range of 1.5-2.0 μm.