High-resolution solder resist dry film and method for manufacturing the same

Abstract

The application relates to the technical field of solder resist dry films, in particular to a high-resolution solder resist dry film and a preparation method thereof. The solder resist dry film comprises a base film and a photosensitive film arranged on the base film. The preparation raw materials of the photosensitive film comprise, in terms of weight parts, 22-30 parts of acrylic resin emulsion, 15-20 parts of active monomer, 20-25 parts of solid auxiliary agent, 0.8-1.5 parts of photoinitiator and 0.5-2 parts of defoaming agent. The synergistic effect between the preparation raw materials of the photosensitive film in the solder resist dry film makes the solder resist dry film have excellent hardness and high resolution.

Description

Technical Field

[0001] This invention relates to the field of solder resist dry film technology, specifically to a high-resolution solder resist dry film and its preparation method. Background Technology

[0002] In recent years, the market demand for highly integrated circuits has been increasing. When soldering circuit components, solder resist film is needed to protect them and prevent solder from depositing on the circuit board during the soldering process. Solder resist film can be liquid or dry film, and dry film is currently more commonly used on highly integrated circuit boards.

[0003] When solder resist dry film is used in conjunction with circuit boards, a certain resolution is required. Generally speaking, the higher the resolution of the solder resist dry film, the finer the circuit can be manufactured, and the better the performance of the circuit will be. This allows electronic products to be made smaller.

[0004] In summary, the resolution of solder resist dry film has a significant impact on the performance of electronic products. Summary of the Invention

[0005] To facilitate a clearer understanding of the technical solutions and effects of this invention, the following detailed description, in conjunction with specific embodiments, is provided. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the definitions in this specification shall prevail.

[0006] The purpose of this invention is to provide a new high-resolution solder resist dry film.

[0007] To achieve the above objectives, the first aspect of the present invention provides a high-resolution solder resist dry film, which includes a substrate film and a photosensitive film disposed on the substrate film. By weight, the raw materials for preparing the photosensitive film include: 22-30 parts of acrylic resin emulsion, 15-20 parts of active monomer, 20-25 parts of solid additives, 0.8-1.5 parts of photoinitiator, and 0.5-2 parts of defoamer.

[0008] The solid additives are surfactant-modified hydrotalcite and nano-zirconia.

[0009] In this invention, surfactant-modified hydrotalcite and nano-zirconia are used as solid nano-additives to prepare a solder resist dry film that not only has high resolution but also excellent wear resistance.

[0010] As a preferred embodiment of the present invention, the weight ratio of the surfactant-modified hydrotalcite to nano-zirconia is 1:(0.1-1), preferably 1:(0.4-0.5).

[0011] As a preferred embodiment of the present invention, the average particle size of the nano-zirconia is 10-500 nm, preferably 50-100 nm.

[0012] The nano-zirconia in this invention can be obtained commercially, preferably the HN-R80Y3 nano-zirconia from Hangzhou Hengna.

[0013] As a preferred technical solution of the present invention, the preparation method of the surfactant-modified hydrotalcite includes: mixing hydrotalcite, water and surfactant, stirring at 70-80°C for 2-3 hours, and then filtering and drying to obtain the surfactant-modified hydrotalcite.

[0014] As a preferred technical solution of the present invention, when preparing surfactant-modified hydrotalcite, the weight of the surfactant is 10-50% of the weight of the hydrotalcite, preferably 20-40%.

[0015] As a preferred technical solution of the present invention, when preparing surfactant-modified hydrotalcite, the weight of water is 30-50 times that of hydrotalcite.

[0016] As a preferred embodiment of the present invention, the surfactant is sodium α-olefin sulfonate.

[0017] As a preferred technical solution of the present invention, the hydrotalcite is magnesium aluminum hydrotalcite, preferably with an average particle size of 0.1-1 μm, more preferably 0.5-0.8 μm, and even more preferably 0.6 μm.

[0018] In this invention, the magnesium aluminum hydrotalcite is commercially available, preferably the magnesium aluminum hydrotalcite from Kesseborg.

[0019] Hydrotalcite can better increase the thermal stability of resins. However, in this system, which is an aqueous structure, the large number of non-crosslinked hydroxyl groups on the surface of hydrotalcite particles makes it easy for hydrotalcite to aggregate during the preparation process. In this invention, surfactant-modified hydrotalcite has excellent dispersibility in the system. Furthermore, the surfactant coating on the surface of the surfactant-modified hydrotalcite can also promote the dispersibility of nano-zirconia in water, resulting in a better performance of the prepared solder resist dry film. It was also found that when the surfactant is sodium α-alkenyl sulfonate, the resolution of the solder resist dry film can be better increased, possibly because the addition of sodium α-alkenyl sulfonate can increase the density of double bonds in the system.

[0020] As a preferred technical solution of the present invention, the acrylic resin emulsion is selected from silicone-modified acrylic resin emulsion and water-based alkali-soluble acrylic resin emulsion, preferably with a weight ratio of silicone-modified acrylic resin emulsion to water-based alkali-soluble acrylic resin emulsion of 1:(1-10), more preferably 1:(3-5).

[0021] The solder resist dry film prepared by using two specific acrylic resin emulsions in this invention has excellent adhesion and hardness.

[0022] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the viscosity of the organosilicon modified acrylic resin at 25±2℃ is 3500-4000Mpa.s.

[0023] In this invention, the silicone-modified acrylic resin can be obtained commercially, such as DB1223 silicone-modified acrylic resin from Anhui Zhongen Chemical Co., Ltd.

[0024] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the solid content of the water-based alkali-soluble acrylic resin emulsion is 30-50%, preferably 42-47%, and more preferably 45%.

[0025] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the viscosity of the water-based alkali-soluble acrylic resin emulsion at 25±2℃ is 15-30 mpa.s, preferably 25 mpa.s.

[0026] The water-based alkali-soluble acrylic resin emulsion in this invention is commercially available, preferably Covestro Neocryl BT-24.

[0027] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the solid content of the organosilicon modified acrylic resin emulsion is 40-50%, preferably 45-50%, and more preferably 47%.

[0028] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the viscosity of the organosilicon modified acrylic resin emulsion at 25±2℃ is 200-500cps, preferably 300cps.

[0029] In this invention, the silicone-modified acrylic resin can be obtained commercially, preferably the SA-109 silicone-modified acrylic resin from Anhui Zhongen Chemical Co., Ltd.

[0030] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the active monomer is selected from at least one of 1,6-hexanediol diacrylate, isobornyl acrylate, dipropylene glycol diacrylate, β-hydroxyethyl methacrylate, ethoxylated bisphenol A diacrylate, pentadecylethoxytrimethylolpropane triacrylate, and nonaethoxytrimethylolpropane triacrylate.

[0031] In this invention, in order to further improve the performance of the solder resist dry film, as a preferred technical solution of this invention, the active monomer is ethoxylated bisphenol A diacrylate and pentadecylethoxytrimethylolpropane triacrylate, preferably in a weight ratio of 1:(1.5-5), and more preferably 1:(2-3).

[0032] The acrylic resin emulsion used in this invention is water-based. The inventors discovered that using pentadecylethoxytrimethylolpropane triacrylate can increase the storage stability and film-forming properties of the raw materials. This may be because the ethoxy group has excellent hydrophilic properties, increasing the overall compatibility of the raw materials. However, the ethoxy group segments may be relatively soft and may penetrate into the coating during film formation, causing film deformation and resulting in poor light transmittance. Consequently, the resolution of the solder resist dry film prepared using pentadecylethoxytrimethylolpropane triacrylate as the active monomer alone is poor. Through extensive research, the inventors unexpectedly discovered that using ethoxylated bisphenol A diacrylate and pentadecylethoxytrimethylolpropane triacrylate together as active monomers can increase the resolution of the solder resist dry film.

[0033] According to a preferred embodiment of the present invention, the photoinitiator is selected from at least one of Irgacure 2959, Irgacure 500, Darocur 1173, Irgacure 184 and Irgacure ITX, preferably Irgacure 2959.

[0034] In this invention, the use of Irgacure 2959 can further increase the resolution of the solder resist dry film.

[0035] As a preferred embodiment of the present invention, the defoamer is a polyether-modified silicone defoamer, such as TEGO Airex 901W and TEGO foamex 825 from EVONIK.

[0036] In this invention, coloring agents and other raw materials may also be added as needed.

[0037] As a preferred embodiment of the present invention, the thickness of the photosensitive film is 20-80 μm, preferably 25-60 μm.

[0038] As a preferred embodiment of the present invention, the thickness of the substrate film is 30-50 μm.

[0039] As a preferred embodiment of the present invention, the substrate membrane is made of one of polyethylene, polytetrafluoroethylene, polycarbonate or polypropylene.

[0040] The same type of substrate membrane is used in all embodiments of the present invention.

[0041] To make the high-temperature and high-humidity resistant solder resist dry film of the present invention easier to store, as a preferred technical solution of the present invention, the solder resist dry film further includes a release protective film disposed on the photosensitive coating film. The specific material of the release protective film is not particularly limited and can be a conventional release protective film in the art. There is no particular limitation in this invention. The thickness of the release protective film is particularly limited, generally 30-40 μm.

[0042] The same type of release protective film is used in all embodiments of the present invention.

[0043] The second aspect of the present invention provides a method for preparing a high-resolution solder resist dry film, comprising: mixing the raw materials for preparing the photosensitive film described in the first aspect of the present invention and coating them onto a substrate film, followed by drying.

[0044] As a preferred technical solution of the present invention, the coating can be a conventional method in the art, such as using a comma coating machine to coat at a speed of 20-30 m / min. The coating amount can be selected according to the final required thickness of the photo-coated film, which will not be elaborated here.

[0045] As a preferred technical solution of the present invention, the drying temperature is 100-130℃, and the drying time is not particularly limited, as long as it is completely dried, which will not be elaborated here.

[0046] In order to make the high temperature and high humidity resistant solder resist dry film of the present invention easier to store, as a preferred technical solution of the present invention, a release protective film is attached to the surface of the photosensitive film after drying.

[0047] As a preferred embodiment of the present invention, the solder resist dry film is first applied to a circuit board (e.g., PCB board, SLP board, etc.) during use. Then, after removing the release liner, vacuum pressing is performed (pressing conditions: temperature 60-70℃, vacuum time 15-30s, pressing time 15-30s, pressing pressure 0.4-0.6kg / cm²). 3 Then, in a 6-8KW exposure machine at 300-400mj / cm 2 Expose the substrate film to remove it; develop the circuit board product in a 0.8-1.2wt% sodium carbonate aqueous solution at 28-32℃ for 60-90s, and then cure it in nitrogen at 150℃ for 60min.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] The synergistic effect between the raw materials used in the preparation of the photosensitive film in the solder resist dry film of the present invention gives the solder resist dry film of the present invention excellent hardness and high resolution. Detailed Implementation

[0050] The present invention will now be described in detail through embodiments, in which:

[0051] The water-based alkali-soluble acrylic resin emulsion is Covestro Neocryl BT-24, with a solid content of 45% and a viscosity of 25 mPa·s at 25°C; the silicone-modified acrylic resin is Anhui Zhongen Chemical's SA-109 silicone-modified acrylic resin; the magnesium aluminum hydrotalcite is KSM's magnesium aluminum hydrotalcite with an average particle size of 0.6 μm; and the nano-zirconia is Hangzhou Hengna's HN-R80Y3 nano-zirconia with an average particle size of 85 nm.

[0052] Example 1

[0053] (1) Preparation of surfactant-modified hydrotalcite: Hydrotalcite, water (40 times the weight of hydrotalcite), and sodium α-olefin sulfonate (0.4 times the weight of hydrotalcite) were mixed and stirred at 85°C for 3 hours. After that, the mixture was filtered and dried to obtain the surfactant-modified hydrotalcite.

[0054] (2) Prepare the raw materials for the preparation of photosensitive film. By weight, take 5 parts of silicone-modified acrylic resin emulsion, 25 parts of water-based alkali-soluble acrylic resin emulsion, 5 parts of ethoxylated bisphenol A diacrylate, 10 parts of pentadecylethoxytrimethylolpropane triacrylate, 15 parts of surfactant-modified hydrotalcite, 6 parts of nano-zirconia, 1 part of Irgacure 2959, and 1 part of TEGOfoamex 825 defoamer.

[0055] (2) Preparation of solder resist dry film: After mixing the raw materials for preparing photosensitive film, the mixture is coated onto a carrier film with a thickness of 35 μm using a comma coating machine at a speed of 24 m / min. After drying at 100°C, the film is laminated on top to form a release protective film with a thickness of 35 μm, and finally the solder resist dry film is obtained. The thickness of the photosensitive film is 25 μm.

[0056] Example 2

[0057] (1) Preparation of surfactant-modified hydrotalcite: Hydrotalcite, water (30 times the weight of hydrotalcite), and sodium α-olefin sulfonate (0.2 times the weight of hydrotalcite) were mixed and stirred at 90°C for 2.5 h. After that, the mixture was filtered and dried to obtain the surfactant-modified hydrotalcite.

[0058] (2) By weight, take 6 parts of silicone-modified acrylic resin emulsion, 21 parts of water-based alkali-soluble acrylic resin emulsion, 6 parts of ethoxylated bisphenol A diacrylate, 18 parts of pentadecylethoxytrimethylolpropane triacrylate, 15 parts of surfactant-modified hydrotalcite, 7.5 parts of nano-zirconia, 1.5 parts of Irgacure 2959, and 1 part of TEGO foamex 825 defoamer;

[0059] (3) Preparation of solder resist dry film: After mixing the raw materials for preparing photosensitive film, the mixture is coated onto a carrier film with a thickness of 35 μm using a comma coating machine at a speed of 24 m / min. After drying at 100 °C, the film is laminated on top to form a release protective film with a thickness of 35 μm, and finally the solder resist dry film is obtained. The thickness of the photosensitive film is 25 μm.

[0060] Example 3

[0061] (1) Preparation of surfactant-modified hydrotalcite: Hydrotalcite, water (30 times the weight of hydrotalcite), and sodium α-olefin sulfonate (0.2 times the weight of hydrotalcite) were mixed and stirred at 90°C for 2.5 h. After that, the mixture was filtered and dried to obtain the surfactant-modified hydrotalcite.

[0062] (2) Prepare the raw materials for the photosensitive film. By weight, take 5.5 parts of silicone-modified acrylic resin emulsion, 22 parts of water-based alkali-soluble acrylic resin emulsion, 5 parts of ethoxylated bisphenol A diacrylate, 12.5 parts of pentadecylethoxytrimethylolpropane triacrylate, 15 parts of surfactant-modified hydrotalcite, 6 parts of nano-zirconia, 1 part of Irgacure 2959, and 1 part of TEGO foamex 825 defoamer.

[0063] (3) Preparation of solder resist dry film: After mixing the raw materials for preparing photosensitive film, the mixture is coated onto a carrier film with a thickness of 35 μm using a comma coating machine at a speed of 24 m / min. After drying at 100 °C, the film is laminated on top to form a release protective film with a thickness of 35 μm, and finally the solder resist dry film is obtained. The thickness of the photosensitive film is 25 μm.

[0064] Example 4

[0065] The method of Example 3 is the same, except that sodium stearate is used instead of sodium α-alkenyl sulfonate when preparing surfactant-modified hydrotalcite, and the prepared surfactant-modified hydrotalcite is used to prepare solder resist dry film according to the method of Example 3.

[0066] Example 5

[0067] The method of Example 3 differs in that: the raw materials for preparing the photosensitive film are prepared by weight as follows: 5.5 parts of silicone-modified acrylic resin emulsion, 22 parts of water-based alkali-soluble acrylic resin emulsion, 17.5 parts of pentadecylethoxytrimethylolpropane triacrylate, 15 parts of surfactant-modified hydrotalcite, 6 parts of nano-zirconia, 1 part of Irgacure 2959, and 1 part of TEGO foamex 825 defoamer.

[0068] A solder resist dry film was then prepared according to the method in Example 3.

[0069] Example 6

[0070] The method of Example 3 is followed, except that Irgacure 500 is used instead of Irgacure 2959, and the solder resist dry film is prepared according to the method of Example 3.

[0071] Comparative Example 1

[0072] The method of Example 3 differs in that: the raw materials for preparing the photosensitive film are prepared by weight as follows: 5.5 parts of silicone-modified acrylic resin emulsion, 22 parts of water-based alkali-soluble acrylic resin emulsion, 5 parts of ethoxylated bisphenol A diacrylate, 12.5 parts of pentadecylethoxytrimethylolpropane triacrylate, 21 parts of hydrotalcite, 1 part of Irgacure 2959, and 1 part of TEGO foamex 825 defoamer.

[0073] A solder resist dry film was then prepared according to the method in Example 3.

[0074] Comparative Example 2

[0075] The method of Example 3 differs in that: the raw materials for preparing the photosensitive film are prepared by weight as follows: 5.5 parts of silicone-modified acrylic resin emulsion, 22 parts of water-based alkali-soluble acrylic resin emulsion, 5 parts of ethoxylated bisphenol A diacrylate, 12.5 parts of pentadecylethoxytrimethylolpropane triacrylate, 21 parts of surfactant-modified hydrotalcite, 1 part of Irgacure 2959, and 1 part of TEGO foamex 825 defoamer.

[0076] A solder resist dry film was then prepared according to the method in Example 3.

[0077] Performance testing

[0078] The solder resist films from the comparative and examples were respectively applied to the PCB board. After removing the release liner, vacuum bonding was performed (bonding conditions: temperature 60℃, vacuum time 20s, bonding time 20s, bonding pressure 0.4kg / cm²). 3 Then, in an 8KW exposure machine at 400mj / cm2 Expose the circuit board to remove the substrate film; develop it in a 1 wt% sodium carbonate aqueous solution at 30°C for 80 seconds, and then cure it in nitrogen at 150°C for 60 minutes.

[0079] (1) Use a hardness tester to test the surface hardness of circuit board products coated with solder resist dry film;

[0080] (2) Resolution test: The minimum value of the pattern of the unexposed part of the developed dry film after exposure, development and curing test using a pattern of L / S = 1 / 1 (10-150um).

[0081] The test results are shown in Table 1.

[0082] Example 1 73um 5H Example 2 72um 5H Example 3 75um 5H Example 4 58um 5H Example 5 60um 4H Example 6 67um 5H Comparative Example 1 38um 4H Comparative Example 2 50um 4H

[0083] As can be seen from the above embodiments and comparative examples, the solder resist dry film prepared by the present invention has excellent resolution and excellent hardness.

Claims

1. A solder resist dry film, characterized in that, The solder resist dry film includes a substrate film and a photosensitive film disposed on the substrate film. By weight, the raw materials for preparing the photosensitive film include: 22-30 parts of acrylic resin emulsion, 15-20 parts of active monomer, 20-25 parts of solid additives, 0.8-1.5 parts of photoinitiator, and 0.5-2 parts of defoamer. The solid additives are surfactant-modified hydrotalcite and nano-zirconia. The surfactant-modified hydrotalcite is sodium α-alkenyl sulfonate-modified hydrotalcite, and the sodium α-alkenyl sulfonate is 0.2 to 0.4 times the weight of the hydrotalcite.

2. The solder resist dry film according to claim 1, characterized in that, The weight ratio of the surfactant-modified hydrotalcite to nano-zirconia is 1:(0.1-1).

3. The solder resist dry film according to claim 1 or 2, characterized in that, The method for preparing the surfactant-modified hydrotalcite includes: mixing hydrotalcite, water, and surfactant, stirring at 70-80℃ for 2-3 hours, and then filtering and drying to obtain the surfactant-modified hydrotalcite.

4. The solder resist dry film according to claim 1 or 2, characterized in that, The acrylic resin emulsion is selected from silicone-modified acrylic resin emulsion and water-based alkali-soluble acrylic resin emulsion.

5. The solder resist dry film according to claim 4, characterized in that, The water-based alkali-soluble acrylic resin emulsion has a solid content of 30-50% and a viscosity of 15-30 mPa·s at 25±2℃.

6. The solder resist dry film according to claim 1 or 2, characterized in that, The active monomer is selected from at least one of 1,6-hexanediol diacrylate, isobornyl acrylate, dipropylene glycol diacrylate, β-hydroxyethyl methacrylate, ethoxylated bisphenol A diacrylate, pentadecylethoxytrimethylolpropane triacrylate, and nonaethoxytrimethylolpropane triacrylate.

7. The solder resist dry film according to claim 1 or 2, characterized in that, The photoinitiator is selected from at least one of Irgacure 2959, Irgacure 500, Darocur 1173, Irgacure 184 and Irgacure ITX.

8. The solder resist dry film according to claim 1 or 2, characterized in that, The defoamer is a polyether-modified silicone defoamer.

9. A method for preparing a solder resist dry film according to any one of claims 1-8, characterized in that, The preparation method includes: mixing the raw materials for preparing the photosensitive film and coating them onto a substrate film, followed by drying.

10. The preparation method according to claim 9, characterized in that, The drying temperature is 100-130℃.