Efficient copper film circuit etching and surface optimization treatment process method

Abstract

The invention relates to the technical field of copper film circuits, in particular to a high-efficiency copper film circuit etching and surface optimization treatment process method which comprises the following steps: S1, pressing a film; s2, performing exposure; s3, developing; s4, etching is carried out; s5, demolding; s6, primary water washing; s7, detecting; s8, carrying out plasma treatment; s9, demolding again; s10, secondary water washing; s11, carrying out secondary inspection; and S12, film covering. Through a series of fine steps and an advanced detection technology, accurate etching and surface treatment of the copper film circuit are achieved, and it is ensured that the quality and performance of a product meet the design requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of copper film circuits, and specifically provides a process method for efficient etching and surface optimization treatment of copper film circuits. Background Art

[0002] In the existing patent CN202410446274.7, a preparation method for improving the appearance defect of a transparent shielding film is proposed. In this method, the surface dyne value of the substrate is controlled between 32 - 40, which can not only ensure the adhesion of a 2 - 7um copper film on the transparent substrate, but also avoid the adsorbed dissolved photoresist on the substrate resulting in color difference. On the premise of ensuring the transmittance and electromagnetic shielding effectiveness, the grid aperture is set between 170 - 425um, reducing excessive sharp angles and avoiding the residue of developing solution in the grid. However, to meet the market demand, it is necessary to use a thicker copper film or a denser grid pattern to form products with specific functions. In this case, the dry film residue is difficult to wash away when embedded in the groove, so improvement is needed. Summary of the Invention

[0003] The purpose of the present invention is to provide a process method for efficient etching and surface optimization treatment of copper film circuits to solve the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A process method for efficient etching and surface optimization treatment of copper film circuits, including the following steps:

[0005] S1: Film pressing, using a film pressing machine to hot - press a layer of anti - etching dry film on the copper - plated surface, and this layer of dry film plays a role in protecting the non - circuit area in the subsequent steps;

[0006] S2: Exposure, exposing the copper film covered with the dry film through an exposure machine, so that the part that needs to form a circuit is sensitized and solidified, and the non - sensitized part will be removed in the subsequent steps;

[0007] S3: Development, putting the exposed copper film into a developing machine, and removing the unexposed part of the dry film by spraying, thereby exposing the area to be etched on the copper film;

[0008] S4: Etching, using an acid solution to remove the area to be etched on the copper film to form a fine circuit pattern;

[0009] S5: Film stripping, using an alkaline solution to remove the solidified liquid resist on the copper layer surface to obtain the required circuit pattern;

[0010] S6: Primary water washing, using pure water to wash away the residual alkaline solution or part of the dry film residue, and then quickly drying it with hot air;

[0011] S7: Detection is carried out by combining manual observation and instrument detection to check whether there are color differences on the surface of the sample. The sample is placed against black and white backgrounds, observed from multiple angles with a strong flashlight, and relevant parameters (such as transmittance, haze, LAB values) and data such as line width and line spacing are recorded.

[0012] S8: Plasma treatment

[0013] First stage: Use 99.99% N2 gas to generate plasma, make the whole system in an N2 atmosphere, and activate the residual dry film to facilitate subsequent reactions.

[0014] Second stage: Introduce a mixed gas of CF 4 and O2 (the proportion of CF 4 is 5%-20%), and treat it at a temperature of 20°C - 35°C for 15 - 40 seconds. This stage aims to further clean.

[0015] S9: Remove the film again, and use an alkaline solution to remove the possible residual dry film or other impurities after plasma treatment.

[0016] S10: Secondary water washing, use pure water again to wash away the residual alkaline solution and quickly dry it with hot air.

[0017] S11: Secondary inspection, check the color difference on the surface of the sample again according to the previous detection method, and adjust the plasma treatment time or temperature as needed until the appearance of the sample meets the qualified standard. At the same time, record the performance parameters of the sample.

[0018] S12: Film laminating, lay a layer of protective film on the surface of the circuit to prevent contamination and damage, and prepare for the sample to enter the subsequent processes.

[0019] Preferably, after the S1 film pressing, the substrate is placed in a drying oven, and appropriate temperature and time are set, usually between 60 - 80°C, and the drying time is about 20 - 30 minutes. Avoid too high temperature to prevent premature curing of the photosensitive glue or deformation of the substrate. It is necessary to ensure air circulation in the drying oven for uniform drying. Sometimes there will be problems with coating cracking, and the drying temperature needs to be reduced and the drying time extended. If there is a problem with insufficient coating adhesion, the drying temperature needs to be increased or the drying time extended.

[0020] Preferably, a cleaning mechanism is required in both the primary water washing and secondary water washing steps. The cleaning mechanism includes a cleaning tank, and two groups of cleaning components are symmetrically arranged in the cleaning tank. The cleaning components are used to rinse the products installed on the hanging rack and immersed in the cleaning tank.

[0021] Preferably, the cleaning assembly includes an installation box body which is installed at the bottom end of the support frame. Several rotating cylinders are rotatably installed on the front surface of the installation box body. A number of water spraying holes are evenly arranged on the front surface of the rotating cylinder. A secondary water injection pipe is connected to the back surface of the rotating cylinder. A main water injection pipe is arranged on the back surface of the installation box body. The main water injection pipe is a flexible pipe and is communicated with the secondary water injection pipe. Cleaning liquid is injected into the secondary water injection pipe through the main water injection pipe. The cleaning liquid soaks into the rotating cylinder and sprays out from the water spraying holes. A worm gear ring is arranged on the outer side wall of the rotating cylinder. A rotating shaft is installed in the installation box body. Several sections of worm gears are arranged on the rotating shaft. Each section of worm gear is in one-to-one meshing connection with the worm gear ring on each rotating cylinder. A driven gear is connected to the end of the rotating shaft. An adjusting motor is installed inside the installation box body. The output end of the adjusting motor is connected with a driving gear, and the driving gear is meshed with the driven gear.

[0022] Preferably, the upper end of the support frame is connected to an adjusting device, and the adjusting device is used to adjust the position height of the cleaning assembly.

[0023] Preferably, a circular hole is opened at the center of the back surface of the rotating cylinder, and a sealing bearing is installed in the circular hole. The end of the secondary water injection pipe is fixedly inserted into the inner ring of the sealing bearing.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] For the yellow light etching process of thick copper films proposed by the present invention, the line width fluctuation range is within ±3 um. Therefore, plasma treatment is added. The plasma treatment has a short time, a low temperature, and a mild reaction, and has little influence on the line width (loss < 0.5 um). Part of the dry film dissolution product is embedded in the groove and is difficult to be washed away by water. Part of it forms a thin complex with copper ions. After being removed, the line changes from rough to smooth and the width decreases slightly. After plasma treatment, the product performance is still within the design requirements. Through a series of fine steps and advanced detection technologies, the present invention realizes the precise etching and surface treatment of copper film lines, ensuring that the quality and performance of the product meet the design requirements. Description of the Drawings

[0026] Figure 1 It is the process flow chart of the present invention.

[0027] Figure 2 It is the structural schematic diagram of the cleaning assembly of the present invention.

[0028] Figure 3 It is the structural schematic diagram of the installation box body of the present invention.

[0029] Figure 4 It is the internal structure diagram of the installation box body of the present invention.

[0030] Figure 5This is a schematic diagram of the connecting structure of the rotary drum of the present invention.

[0031] In the figure: mounting box 1, support frame 2, rotary drum 3, water spray holes 4, worm gear ring 5, secondary water injection pipe 6, main water injection pipe 7, rotating shaft 8, worm 9, driven gear 10, adjustment motor 11, driving gear 12. Specific embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Please refer to Figures 1 to 5 , the present invention provides a technical solution: a process method for efficient copper film circuit etching and surface optimization treatment, including the following steps:

[0034] S1: Film pressing, using a film press to hot-press a layer of anti-etching dry film on the copper-plated surface, and this layer of dry film plays a role in protecting the non-circuit area in the subsequent steps;

[0035] S2: Exposure, exposing the copper film covered with the dry film through an exposure machine, so that the parts that need to form the circuit are sensitized and cured, and the unexposed parts will be removed in the subsequent steps;

[0036] S3: Development, putting the exposed copper film into a developing machine, and removing the unexposed part of the dry film by spraying, so as to expose the area to be etched on the copper film;

[0037] S4: Etching, using an acid solution to remove the area to be etched on the copper film to form a fine circuit pattern. Attention should be paid to the problem of side etching during etching. Side etching is a common problem in the PCB etching process. It means that the etchant not only etches along the vertical direction of the copper foil, but also etches along the side of the copper foil, resulting in the thinning of the circuit sidewall and even the breakage of the circuit. Some methods can be used to reduce side etching: optimize the etchant: select an etchant with less side etching, such as using an alkaline etching solution instead of the traditional acidic etching solution; adjust process parameters: reduce the temperature and concentration of the etching solution to reduce the attack on the sidewall; improve the design: increase the circuit width, avoid too thin circuit design, use a thicker copper foil to improve the side etching resistance of the circuit; improve the solution flow: by improving the stirring method, make the etching solution flow uniformly on the PCB surface to reduce the impact on the sidewall, etc.;

[0038] S5: Demasking, using an alkaline solution to remove the cured liquid resist on the copper layer surface to obtain the required circuit pattern;

[0039] S6: Primary water wash, using pure water to remove the residue of the alkaline solution or part of the dry film residue, and then quickly drying it with hot air;

[0040] S7: Inspection, adopting a combination of manual observation and instrument detection to check whether there are color differences on the surface of the sample. Place the sample under black and white backgrounds, observe it from multiple angles with a strong flashlight, and record relevant parameters (such as transmittance, haze, LAB value) and data such as line width and line spacing;

[0041] S8: Plasma treatment,

[0042] First stage: Generate plasma using 99.99% N2 gas to make the whole system in an N2 atmosphere, activate the residual dry film, and facilitate subsequent reactions;

[0043] Second stage: Introduce a mixed gas of CF 4 and O2 (the proportion of CF 4 is 5%-20%), and treat it at a temperature of 20°C - 35°C for 15 - 40 seconds. This stage aims to further clean;

[0044] S9: Remove the film again, using an alkaline solution to remove the possible residual dry film or other impurities after plasma treatment;

[0045] S10: Secondary water wash, using pure water again to remove the residue of the alkaline solution and quickly drying it with hot air;

[0046] S11: Sub - inspection, check the color difference on the surface of the sample again according to the previous inspection method, and adjust the plasma treatment time or temperature as needed until the appearance of the sample meets the qualified standard. At the same time, record the performance parameters of the sample;

[0047] S12: Film laminating, lay a protective film flat on the circuit surface to prevent contamination and damage, and prepare for the sample to enter the subsequent processes.

[0048] After S1 film laminating, put the substrate into a drying oven, set appropriate temperature and time, usually between 60 - 80°C, and the drying time is about 20 - 30 minutes. Avoid too high temperature to prevent the photosensitive glue from curing in advance or the substrate from deforming. It is necessary to ensure air circulation in the drying oven for uniform drying. Sometimes there will be problems such as coating cracking, in which case the drying temperature needs to be reduced and the drying time extended. If there is a problem of insufficient coating adhesion, the drying temperature needs to be increased or the drying time extended.

[0049] For the yellow light etching process of thick copper films, the line width fluctuation range is within ±3 μm. Therefore, plasma treatment is added. The plasma treatment has a short time, low temperature, and mild reaction, and has little impact on the line width (loss < 0.5 μm). Part of the dry film dissolution product is embedded in the groove and difficult to be washed away by water, and part forms a thin complex with copper ions. After being removed, the line changes from rough to smooth and the width decreases slightly. After plasma treatment, the product performance is still within the design requirements. Through a series of fine steps and advanced detection technologies, the present invention realizes precise etching and surface treatment of the copper film circuit, ensuring that the quality and performance of the product meet the design requirements.

[0050] In the primary water washing and secondary water washing steps, a cleaning mechanism needs to be used. The cleaning mechanism includes a cleaning pool, and two groups of cleaning components are symmetrically arranged in the cleaning pool. The cleaning components are used to rinse the products mounted on the hanging rack and immersed in the cleaning pool.

[0051] The cleaning component includes a mounting box body 1. The mounting box body 1 is mounted at the bottom end of a support frame 2. The upper end of the support frame 2 is connected to an adjusting device, and the adjusting device is used to adjust the position height of the cleaning component. Several rotating cylinders 3 are rotatably mounted on the front surface of the mounting box body 1. A number of spray holes 4 are evenly arranged on the front surface of the rotating cylinder 3. A secondary water injection pipe 6 is connected to the back surface of the rotating cylinder 3. A round hole is opened at the center of the back surface of the rotating cylinder 3, and a sealing bearing is installed in the round hole. The end of the secondary water injection pipe 6 is fixedly inserted into the inner ring of the sealing bearing. A main water injection pipe 7 is arranged on the back surface of the mounting box body 1. The main water injection pipe 7 is a flexible pipe, and the main water injection pipe 7 is communicated with the secondary water injection pipe 6. Cleaning liquid is injected into the secondary water injection pipe 6 through the main water injection pipe 7. The cleaning liquid soaks into the rotating cylinder 3 and sprays out from the spray holes 4. A worm gear ring 5 is arranged on the outer side wall of the rotating cylinder 3. A rotating shaft 8 is installed in the mounting box body 1. Several sections of worm gears 9 are arranged on the rotating shaft 8. Each section of worm gear 9 is meshed and connected with the worm gear ring 5 on each rotating cylinder 3 in a one-to-one correspondence. A driven gear 10 is connected to the end of the rotating shaft 8. An adjusting motor 11 is installed inside the mounting box body 1. The output end of the adjusting motor 11 is connected with a driving gear 12, and the driving gear 12 is meshed and connected with the driven gear 10.

[0052] During actual use, when the substrate is mounted on the hanging rack and immersed in the cleaning pool for cleaning, the cleaning pool already contains cleaning agents, which can clean the surface. Then, cleaning agents are injected into the rotating cylinder 3 through the main water injection pipe 7 and the secondary water injection pipe 6, and then sprayed out from the spray holes 4 onto the surface of the substrate. The two sides of the substrate are rinsed simultaneously. At the same time, the adjusting motor 11 is started to drive the driving gear 12 to rotate. Since the driving gear 12 is meshed and connected with the driven gear 10, the rotating shaft 8 and the worm gear 9 can be rotated. The worm gear 9 is meshed and connected with the worm gear ring 5, so that the rotating cylinder 3 rotates when rinsing the substrate, and the rinsing is more thorough, which can ensure that the impurities on the surface are removed completely.

[0053] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art will appreciate that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for efficient copper film circuit etching and surface optimization treatment, characterized in that: The following steps are included: S1: Lamination: Use a laminator to heat-press a layer of anti-etching dry film on the copper-plated surface. This dry film protects the non-circuit area in the subsequent steps. S2: Exposure, exposing the copper film covered with the dry film through an exposure machine to make the part where the circuit needs to be formed sensitive to light and solidify, and the unsensitive part will be removed in the subsequent steps; S3: Development, placing the exposed copper film into a developer, removing the unexposed portion of the dry film by spraying, thereby exposing the area to be etched on the copper film; S4: etching, using an acid solution to remove the area to be etched on the copper film to form a fine circuit pattern; S5: stripping, using an alkaline solution to remove the solidified liquid resist on the surface of the copper layer to obtain the desired circuit pattern; S6: Primary water washing, using pure water to remove the residual alkali solution or part of the dry film residue, and then quickly drying with hot air; S7: Detection, using a combination of manual observation and instrument detection to check whether there is color difference on the sample surface; S8: plasma treatment, The first stage: Use 99.99% N2 gas to generate plasma, so that the entire system is in N2 atmosphere, activate the residual dry film, and facilitate subsequent reactions; The second stage: introduce CF4 and O2 mixed gas and treat it at a temperature of 20℃-35℃ for 15-40 seconds. This stage is aimed at further cleaning; S9: De-filming again, using an alkaline solution to remove the dry film or other impurities that may remain after the plasma treatment; S10: Secondary water washing, using pure water to wash again to remove the residual alkaline solution, and then quickly drying with hot air; S11: Second inspection: check the color difference of the sample surface again according to the previous inspection method, and adjust the plasma treatment time or temperature as needed until the sample appearance meets the qualified standard. At the same time, record the performance parameters of the sample; S12: Laminating: Laying a protective film on the circuit surface to prevent contamination and damage, and prepare the sample for subsequent processes.

2. The process for high-efficiency copper film circuit etching and surface optimization treatment according to claim 1 is characterized in that: After the S1 lamination, the substrate is placed in a drying oven, and the appropriate temperature and time are set, usually between 60-80°C, and the drying time is about 20-30 minutes.

3. The process for high-efficiency copper film circuit etching and surface optimization treatment according to claim 1 is characterized in that: A cleaning mechanism is required in both the primary and secondary water washing steps. The cleaning mechanism includes a cleaning tank in which two groups of cleaning components are symmetrically arranged. The cleaning components are used to rinse the products mounted on the rack and immersed in the cleaning tank.

4. The process for high-efficiency copper film circuit etching and surface optimization treatment according to claim 3 is characterized in that: The cleaning assembly comprises a mounting box (1), wherein the mounting box (1) is mounted at the bottom end of a support frame (2), a plurality of rotating drums (3) are rotatably mounted on the front of the mounting box (1), a plurality of water spray holes (4) are evenly arranged on the front of the rotating drum (3), an auxiliary water injection pipe (6) is connected to the back of the rotating drum (3), and a main water injection pipe (7) is arranged on the back of the mounting box (1), the main water injection pipe (7) is a hose, the main water injection pipe (7) and the auxiliary water injection pipe (6) are connected, cleaning liquid is injected into the auxiliary water injection pipe (6) through the main water injection pipe (7), and the cleaning liquid is immersed in the rotating drum (3). ) and is sprayed out from the water spray hole (4); a worm wheel ring (5) is arranged on the outer wall of the rotating drum (3); a rotating shaft (8) is installed in the installation box (1); a plurality of worm gears (9) are arranged on the rotating shaft (8); each worm gear (9) is meshedly connected with the worm wheel ring (5) on each rotating drum (3); a driven gear (10) is connected to the end of the rotating shaft (8); an adjusting motor (11) is installed inside the installation box (1); a driving gear (12) is connected to the output end of the adjusting motor (11); and the driving gear (12) and the driven gear (10) are meshedly connected.

5. The process for high-efficiency copper film circuit etching and surface optimization treatment according to claim 4 is characterized in that: The upper end of the support frame (2) is connected to an adjusting device, and the adjusting device is used to adjust the position height of the cleaning component.

6. The process for high-efficiency copper film circuit etching and surface optimization treatment according to claim 4 is characterized in that: A circular hole is provided at the center of the back side of the rotating drum (3), a sealing bearing is installed in the circular hole, and the end of the auxiliary water injection pipe (6) is fixedly inserted into the inner ring of the sealing bearing.

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