A one-time printing ink process for large-scale high-ounce copper solder mask

Abstract

The present invention discloses a large-scale high-ounce copper solder resist one-time printing ink process, which includes the following steps: step S1, preparation of solder resist ink; step S2, one-time solder resist printing; step S3, pre-baking, one-time exposure; step S4, development, polishing. The present invention discloses a large-scale high-ounce copper solder resist one-time printing ink process, which is simple and easy to operate, has a short process, high production efficiency, low production cost, high yield rate of finished products, can effectively solve the problems of circuit ink bubbles and ink shedding, and improve the quality and grade of PCB.

Description

Technical Field

[0001] The invention belongs to the technical field of PCB production and processing, and specifically relates to a one-time printing ink process for high-ounce copper solder resist for large-scale assembly. Background Art

[0002] PCB (Printed Circuit Board) is a commonly used component in electrical equipment. Usually, various components need to be mounted or plugged into the PCB to form an electrical functional module to realize various functions of the electrical equipment. After the circuit on the PCB is completed, solder mask ink needs to be printed on the surface to protect the circuit on the PCB and avoid short circuits between pads when mounting components.

[0003] With the rapid development of high-end manufacturing industry, the addition of new technologies and equipment such as CNC machinery, Al digital technology, and intelligent robots, electronic products are developing in the direction of "light, thin, short, and small", and the density of PCB is getting higher and higher, and the types and process requirements of silk screen solder mask ink are getting higher and higher. In the existing technology, the solder mask printing of large-scale high-ounce copper (40Z thick copper plate) in the PCB production process usually needs to be separated into two full processes, that is, the first time: pre-treatment → printing → pre-baking → exposure → development → post-baking; the second time: pre-treatment → printing → pre-baking → exposure → development → post-baking (repeat the first full process); this process operation is prone to poor bonding between layers of ink, and is prone to stratification and cracking; low production efficiency, about half of the normal ≤20Z board; high production cost, more than double the normal ≤20Z board; general production quality, unable to solve the problems of double exposure, ghosting after development, ink bubbles between lines, and ink shedding.

[0004] The Chinese invention patent with application number 201910439647.7 discloses an ink screen printing process for thick copper white solder mask ink PCB board. The screen printing process includes the following steps: S1, pre-sandblasting the thick copper PCB board to be screen-printed with solder mask ink, and plugging the vias; S2, screen printing white solder mask ink, and letting it stand; S3, sequentially performing segmented pre-baking, alignment, exposure and development to complete the ink screen printing. The process of the invention can complete a white solder mask ink layer with a shoulder thickness of not less than 7μm on a thick copper PCB board through one screen printing, which improves the efficiency of screen printing, reduces the cost of screen printing, and avoids the problem of easy cracking of the ink layer during die punching; and through segmented pre-baking, not only the standing time after screen printing is shortened, but also the defect of white oil cracks is solved; at the same time, by controlling the energy of exposure and development, the ink layer maintains gloss and clear development, and effectively avoids the disadvantage of white oil cracks that are easy to appear after reflow soldering or wave soldering on the client side. However, this screen printing process does not adjust the ink fluidity and bubble problems. Problems such as ink bubbles and ink shedding between lines will still occur during the screen printing process. It is not suitable for large-scale layout and high-ounce copper solder mask printing.

[0005] Therefore, it is urgent to seek a large-scale high-ounce copper solder mask one-time printing ink process with higher production efficiency, lower production cost, and effective solution to the problems of line ink bubbles and ink shedding. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a large-scale high-ounce copper solder mask one-time printing ink process. The process is simple and easy, with a short process, high production efficiency, low production cost, and a high yield rate of finished products. It can effectively solve the problems of circuit ink bubbles and ink shedding, and improve the quality and grade of PCBs.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a large-scale high-ounce copper solder mask one-time printing ink process, characterized in that it includes the following steps:

[0008] Step S1, preparation of solder resist ink: after uniformly mixing the components of the solder resist ink, stirring for 1-2 hours at 900-1100 RPM / min and 55-65° C. using a high-speed disperser, then stopping stirring, grinding to a fineness of less than 5 μm, and filtering with a 300-500 mesh filter to obtain the solder resist ink;

[0009] Step S2, solder mask printing once: use 60-70 degree scraper glue with 80-100 mesh screen printing solder mask ink indicated in step S1, adjust the horizontal angle between scraper and screen, and grind the scraper glue in a frustrated manner to ensure that the ink thickness after printing reaches more than 40μm;

[0010] Step S3, pre-baking and one-time exposure: first, the ink printed in step S2 is dried until it does not stick to objects, and then the printed solder mask ink is exposed once using an LED semi-automatic exposure machine to ensure UV light penetration of the ink and improve ink adhesion;

[0011] Step S4, development and polishing: the unexposed ink on the pad and the outer side of the pad is removed by a developer, and the solidified ink on the pad is removed by polishing.

[0012] Preferably, the components of the solder mask ink in step S1 include: hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent.

[0013] Preferably, the mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer and diluent is (35-50):(2-5):4:(4-8):3:(0.8-1.3):(6-10):(1-3):(10-20).

[0014] Preferably, the hyperbranched polyurethane acrylate is of fourth generation.

[0015] Preferably, the photoinitiator is at least one of benzoin, benzoin ethyl ether and benzoin isopropyl ether.

[0016] Preferably, the filler is at least one of calcium carbonate, talc, volcanic ash and nano-silicon dioxide.

[0017] Preferably, the defoaming agent is at least one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, and polyoxypropylene polyoxyethylene glycerol ether.

[0018] Preferably, the diluent is at least one of methyl ethyl ketone, cyclohexanone, xylene, n-butanol and styrene.

[0019] Preferably, the screen printing pressure of the solder mask printing in step S2 is 6.3-6.8 kg / cm 2 , screen printing speed 2.4~2.8m / min.

[0020] Preferably, the pre-baking temperature in step S3 is 65-75° C. and the time is 20-40 minutes.

[0021] Preferably, the exposure energy of the single exposure in step S3 is 10-12 levels.

[0022] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the present invention provides a large-scale high-ounce copper solder mask one-time printing ink process, which is simple and easy, has a short process, high production efficiency, low production cost, and a high yield rate of finished products. It can effectively solve the problems of circuit ink bubbles and ink shedding, and improve the quality and grade of PCBs. DETAILED DESCRIPTION

[0023] The preferred embodiments of the present invention will be described in detail below.

[0024] A one-time printing ink process for high-ounce copper solder mask with large-scale slabs, characterized by comprising the following steps:

[0025] Step S1, preparation of solder resist ink: after uniformly mixing the components of the solder resist ink, stirring for 1-2 hours at 900-1100 RPM / min and 55-65° C. using a high-speed disperser, then stopping stirring, grinding to a fineness of less than 5 μm, and filtering with a 300-500 mesh filter to obtain the solder resist ink;

[0026] Step S2, solder mask printing once: use 60-70 degree scraper glue with 80-100 mesh screen printing solder mask ink indicated in step S1, adjust the horizontal angle between scraper and screen, and grind the scraper glue in a frustrated manner to ensure that the ink thickness after printing reaches more than 40μm;

[0027] Step S3, pre-baking and one-time exposure: first, the ink printed in step S2 is dried until it does not stick to objects, and then the printed solder mask ink is exposed once using an LED semi-automatic exposure machine to ensure UV light penetration of the ink and improve ink adhesion;

[0028] Step S4, development and polishing: the unexposed ink on the pad and the outer side of the pad is removed by a developer, and the solidified ink on the pad is removed by polishing.

[0029] Preferably, the components of the solder mask ink in step S1 include: hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent.

[0030] Preferably, the mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer and diluent is (35-50):(2-5):4:(4-8):3:(0.8-1.3):(6-10):(1-3):(10-20).

[0031] Preferably, the hyperbranched polyurethane acrylate is of fourth generation.

[0032] Preferably, the photoinitiator is at least one of benzoin, benzoin ethyl ether and benzoin isopropyl ether.

[0033] Preferably, the filler is at least one of calcium carbonate, talc, volcanic ash and nano-silicon dioxide.

[0034] Preferably, the defoaming agent is at least one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, and polyoxypropylene polyoxyethylene glycerol ether.

[0035] Preferably, the diluent is at least one of methyl ethyl ketone, cyclohexanone, xylene, n-butanol and styrene.

[0036] Preferably, the screen printing pressure of the solder mask printing in step S2 is 6.3-6.8 kg / cm 2 , screen printing speed 2.4~2.8m / min.

[0037] Preferably, the pre-baking temperature in step S3 is 65-75° C. and the time is 20-40 minutes.

[0038] Preferably, the exposure energy of the single exposure in step S3 is 10-12 levels.

[0039] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the present invention provides a large-scale high-ounce copper solder mask one-time printing ink process, which is simple and easy, has a short process, high production efficiency, low production cost, and a high yield rate of finished products. It can effectively solve the problems of circuit ink bubbles and ink shedding, and improve the quality and grade of PCBs.

[0040] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0041] Example 1

[0042] Embodiment 1 provides a large-scale high-ounce copper solder mask printing ink process, characterized in that it includes the following steps:

[0043] Step S1, preparation of solder resist ink: after uniformly mixing the components of the solder resist ink, stirring at 900 RPM / min and 55° C. for 1 h using a high-speed disperser, then stopping stirring, grinding to a fineness of less than 5 μm, and filtering with a 300-mesh filter to obtain the solder resist ink;

[0044] Step S2, solder mask printing once: use 60 degree scraper glue with 80 mesh screen printing solder mask ink indicated in step S1, adjust the horizontal angle between scraper and screen, and grind the scraper glue in a frustrated manner to ensure that the ink thickness after printing reaches more than 40 μm;

[0045] Step S3, pre-baking and one-time exposure: first, the ink printed in step S2 is dried until it does not stick to objects, and then the printed solder mask ink is exposed once using an LED semi-automatic exposure machine to ensure UV light penetration of the ink and improve ink adhesion;

[0046] Step S4, development and polishing: the unexposed ink on the pad and the outer side of the pad is removed by a developer, and the solidified ink on the pad is removed by polishing.

[0047] The components of the solder resist ink in step S1 include: hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent.

[0048] The mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl] vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer and diluent is 35:2:4:4:3:0.8:6:1:10; the hyperbranched polyurethane acrylate is of the fourth generation; the photoinitiator is benzoin; the filler is calcium carbonate; the defoamer is polyoxyethylene polyoxypropylene pentaerythritol ether; and the diluent is methyl ethyl ketone.

[0049] The screen printing pressure for the solder mask printing in step S2 is 6.3 kg / cm 2 , screen printing speed is 2.4m / min; the pre-baking temperature in step S3 is 65°C, and the time is 20 minutes; the exposure energy of one exposure in step S3 is 10 levels.

[0050] Example 2

[0051] Example 2 provides a large-scale high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that the mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl] vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent is 40:3:4:5:3:0.9:7:1.5:12; the silk screen air pressure of the solder mask one-time printing in step S2 is 6.5kg / cm 2 , screen printing speed is 2.5m / min; the pre-baking temperature in step S3 is 67°C, and the time is 25 minutes; the exposure energy of one exposure in step S3 is 10.5 levels.

[0052] Example 3

[0053] Example 3 provides a large-scale high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that the mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl] vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent is 42:3.5:4:6:3:1:8:2:15; the silk screen air pressure of the solder mask one-time printing in step S2 is 6.3-6.8 kg / cm 2, screen printing speed is 2.4-2.8 m / min; the pre-baking temperature in step S3 is 70° C., and the time is 30 minutes; the exposure energy of one exposure in step S3 is level 11.

[0054] Example 4

[0055] Example 4 provides a large-scale high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that the mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl] vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent is 48:4.5:4:7.5:3:1.2:9.5:2.8:19; the silk screen air pressure of the solder mask one-time printing in step S2 is 6.7kg / cm 2 , screen printing speed is 2.7m / min; the pre-baking temperature in step S3 is 74°C, and the time is 38 minutes; the exposure energy of one exposure in step S3 is level 11.5.

[0056] Example 5

[0057] Example 5 provides a large-scale high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that the mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl] vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent is 50:5:4:8:3:1.3:10:3:20; the silk screen air pressure of the solder mask one-time printing in step S2 is 6.8kg / cm 2 , screen printing speed is 2.8m / min; the pre-baking temperature in step S3 is 75°C, and the time is 40 minutes; the exposure energy of one exposure in step S3 is 12 levels.

[0058] Comparative Example 1

[0059] Comparative Example 1 provides a large-plate high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that 2-vinyl-3H-4-quinolinazolone is not added.

[0060] Comparative Example 2

[0061] Comparative Example 2 provides a large-scale high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that zein is not added.

[0062] Comparative Example 3

[0063] Comparative Example 3 provides a large-plate high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that [2-(triethoxysilyl)ethyl] vinyl ether is not added.

[0064] Comparative Example 4

[0065] Comparative Example 4 provides a large-plate high-ounce copper solder mask one-time printing ink process, which is basically the same as Example 1, except that trifluoromethyl trifluorovinyl ether is not added.

[0066] The solder resist ink layers printed in Examples 1-5 and Comparative Examples 1-4 were tested, and the test results are shown in Table 1.

[0067] Table 1

[0068] project Glossiness, % After die stamping Cracking After reflow soldering bubble Example 1 73 No cracking No cracking No cracks No bubbles Example 2 75 No cracking No cracking No cracks No bubbles Example 3 76 No cracking No cracking No cracks No bubbles Example 4 78 No cracking No cracking No cracks No bubbles Example 5 80 No cracking No cracking No cracks No bubbles Comparative Example 1 69 Slight cracking No cracking Micro cracks Microbubbles Comparative Example 2 68 Slight cracking No cracking Micro cracks Microbubbles Comparative Example 3 66 Slight cracking No cracking Micro cracks Microbubbles Comparative Example 4 68 Slight cracking No cracking Micro cracks Microbubbles

[0069] It can be seen from Table 1 that the solder resist ink layer made by the large-plate high-ounce copper solder resist one-time printing ink process involved in the present invention has better comprehensive performance, which is a structure of synergistic effects of various process steps and ink components.

[0070] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A one-time printing ink process for large-scale high-ounce copper solder mask, characterized in that: The steps include: Step S1, preparation of solder resist ink: after uniformly mixing the components of the solder resist ink, stirring for 1-2 hours at 900-1100 RPM / min and 55-65° C. using a high-speed disperser, then stopping stirring, grinding to a fineness of less than 5 μm, and filtering with a 300-500 mesh filter to obtain the solder resist ink; The components of the solder resist ink in step S1 include: hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer, and diluent; The mass ratio of the hyperbranched polyurethane acrylate, 2-vinyl-3H-4-quinolinazolone, zeatin, [2-(triethoxysilyl)ethyl]vinyl ether, trifluoromethyl trifluorovinyl ether, photoinitiator, filler, defoamer and diluent is (35-50):(2-5):4:(4-8):3:(0.8-1.3):(6-10):(1-3):(10-20); Step S2, solder mask printing once: use 60-70 degree scraper glue with 80-100 mesh screen printing solder mask ink indicated in step S1, adjust the horizontal angle between scraper and screen, and grind the scraper glue in a frustrated manner to ensure that the ink thickness after printing reaches more than 40μm; Step S3, pre-baking and one-time exposure: first, the ink printed in step S2 is dried until it does not stick to objects, and then the printed solder mask ink is exposed once using an LED semi-automatic exposure machine to ensure UV light penetration of the ink and improve ink adhesion; Step S4, development and polishing: the unexposed ink on the pad and the outer side of the pad is removed by a developer, and the solidified ink on the pad is removed by polishing.

2. A one-time printing ink process for large-scale high-ounce copper solder resist according to claim 1, characterized in that: The hyperbranched polyurethane acrylate is of fourth generation.

3. A one-time printing process for high-ounce copper solder resist with large-scale slabs according to claim 1, characterized in that: The photoinitiator is at least one of benzoin, benzoin ethyl ether and benzoin isopropyl ether.

4. A one-time printing ink process for large-scale high-ounce copper solder resist according to claim 1, characterized in that: The filler is at least one of calcium carbonate, talcum powder, volcanic ash and nano silicon dioxide.

5. A one-time printing ink process for large-scale high-ounce copper solder resist according to claim 1, characterized in that: The defoaming agent is at least one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, polyoxypropylene glycerol ether, and polyoxypropylene polyoxyethylene glycerol ether; the diluent is at least one of methyl ethyl ketone, cyclohexanone, xylene, n-butanol, and styrene.

6. A one-time printing ink process for large-scale high-ounce copper solder resist according to claim 1, characterized in that: The screen printing pressure of the solder mask printing in step S2 is 6.3-6.8 kg / cm 2 , screen printing speed 2.4~2.8m / min.

7. A one-time printing process for high-ounce copper solder resist with large-scale slabs according to claim 1, characterized in that: The pre-baking temperature in step S3 is 65-75° C. and the time is 20-40 minutes.

8. A one-time printing process for high-ounce copper solder resist with large-scale slabs according to claim 1, characterized in that: The exposure energy of one exposure in step S3 is 10-12 levels.