PCB (Printed Circuit Board) drilling method and application

Abstract

The invention provides a PCB drilling method and application, and the method comprises the steps: S1, preparing an adhesive film base plate which comprises a carrier film and a washing-removable photosensitive resin layer which are sequentially arranged; s2, attaching the removable and washable photosensitive resin layer included in the adhesive film base plate to the lower surface of the PCB, curing, and removing the carrier film after curing; s3, drilling is carried out on the PCB; and S4, washing the photosensitive resin layer capable of being washed after drilling. According to the method for drilling the PCB, the risk of drilling burrs can be restrained, meanwhile, complete film stripping can be achieved, stripping film residues do not exist in the process of stripping and washing the PCB with the blind holes, the blind holes are not blocked, and the PCB drilling quality can be improved.

Description

Technical Field

[0001] This invention belongs to the field of circuit board processing technology, specifically relating to a method and application of PCB drilling. Background Technology

[0002] A backing plate is a material placed under the board to be processed during mechanical drilling of printed circuit boards (PCBs) to improve the drilling effect. The main functions of backing plates for PCB processing are: (1) suppressing burrs at the drill exit; (2) improving hole position accuracy; (3) reducing drill bit temperature; and (4) protecting the drilling machine. The main types of backing plates include: medium-density wood pulp board, high-density wood pulp board, melamine wood backing plate, phenolic paper backing plate, and composite wood backing plate.

[0003] Currently, during PCB manufacturing, numerous uncertainties, including raw materials, processing techniques, equipment, and human factors, can cause slight deformation of the manufactured PCBs, resulting in warping. Warped PCBs cannot adhere tightly to the backing plate, leading to excessive burrs during drilling and pin breakage. In short, PCB deformation significantly impacts drilling. If the PCB is thin (below 3.0 mm), increasing the pressure of the pressure feet during drilling can correct the warping at the drilling location, ensuring a tight fit between the PCB and backing plate and preventing excessive burrs. However, if the PCB is thick (3.0 mm and above), the pressure of the pressure feet is insufficient to correct the warping, resulting in gaps between the PCB and backing plate. This leads to larger burrs or other drilling problems, affecting quality. Currently, this type of PCB deformation-induced drilling burr problem has not been effectively resolved.

[0004] CN118475006A discloses a method for improving burrs and flash on circuit boards using a water-soluble composite film. The method involves heating and melting the water-soluble composite film, then rolling it with a pressing roller and cooling it to fix it onto the lower surface of the PCB board as a backing plate. While this method can prevent burrs and flash during drilling, the high density of blind holes on the PCB board makes it impossible to use a screen protector. Applying the water-soluble composite film can easily clog the blind holes, resulting in residual film residue.

[0005] Therefore, there is a need for a pad and drilling method that can improve PCB drilling without clogging blind holes and causing film residue. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a method and application for PCB drilling.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for drilling holes in a PCB, the method comprising:

[0009] S1. Prepare an adhesive film pad, the adhesive film pad comprising a carrier film and a washable photosensitive resin layer arranged sequentially;

[0010] S2. The washable photosensitive resin layer included in the adhesive film pad is attached to the lower surface of the PCB board and cured. After curing, the carrier film is removed.

[0011] S3. Drill holes in the PCB board;

[0012] S4. After drilling, wash off the washable photosensitive resin layer.

[0013] A schematic diagram of the PCB board with a washable photosensitive resin layer (cured) after curing, as described in this invention, is shown below. Figure 1 As shown in the figure, there are multiple blind holes in the PCB board. If the pad is only bonded to the lower surface of the PCB board by heating and melting, the melting temperature of the pad is too high, and the substances contained in the pad will enter the blind holes, resulting in residual film removal. The present invention directly bonds the washable photosensitive resin layer to the lower surface of the PCB board and uses a photocuring method, which can suppress the risk of drilling burrs and achieve complete film removal without any residue, thus improving the quality of PCB drilling. Specifically:

[0014] i. The washable photosensitive resin layer, with its high surface dryness, forms a semi-cured adhesive film pad. This allows for bonding the adhesive film pad to the underside of the PCB board at a lower melting temperature. The design incorporates a low-flow, washable photosensitive resin, preventing it from flowing into blind vias and causing residue during bonding, thus eliminating quality risks. Figure 1 As shown, the washable photosensitive resin layer will not enter the blind hole;

[0015] ii. The washable photosensitive resin layer is easily deformable, thus enabling it to adhere tightly to the underside of a warped PCB board;

[0016] iii. The washable photosensitive resin layer can be UV cured and has strong adhesion. The washable photosensitive resin layer provided by the present invention can undergo a photocuring reaction under UV irradiation. After curing, the washable photosensitive resin layer can still adhere tightly to the lower surface of the PCB board and has strong adhesion, which can avoid the risk of the pad falling off during drilling.

[0017] iv. The washable photosensitive resin layer has high hardness after curing. The cured washable photosensitive resin layer has high hardness and will not soften during drilling. It can be used as a drilling pad to suppress the disadvantage of drill burrs.

[0018] v. The washable photosensitive resin layer is washable. After drilling, the washable photosensitive resin layer can be removed using a stripping solution, which is simple and easy.

[0019] Therefore, the method for improving PCB drilling provided by the present invention can suppress the risk of drilling burrs and achieve complete film removal without any film residue, which is beneficial to improving the quality of PCB drilling.

[0020] Preferably, the softening temperature of the washable photosensitive resin layer after surface drying is ≥30℃, such as 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 100℃, 110℃, 120℃, etc., and more preferably 40-90℃.

[0021] By limiting the softening temperature of the washable photosensitive resin layer after surface drying to above room temperature, this invention can prevent adhesive dripping when the adhesive film pad is placed or stored at room temperature. At the same time, when bonding it to the lower surface of the PCB board, it is only necessary to heat it to above the softening temperature so that it can adhere to the PCB board.

[0022] In this invention, the softening temperature is tested using thermomechanical analysis (TMA).

[0023] Preferably, the hardness of the washable photosensitive resin layer after UV curing is ≥5 B, such as 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, etc.

[0024] The washable photosensitive resin layer provided by this invention has high hardness after UV curing and will not soften during drilling. It can be used as a drilling pad to suppress drilling burrs.

[0025] In this invention, the hardness is obtained by testing according to the test method of GB / T 6739-2022 "Determination of Hardness of Paint Film by Pencil Method".

[0026] Preferably, the metal adhesion of the washable photosensitive resin layer is ≤2 grade, such as grade 2, grade 1 or grade 0.

[0027] The present invention specifies that the washable photosensitive resin layer has excellent adhesion to the metal, which can avoid the risk of the washable photosensitive resin layer falling off the metal surface during the PCB board processing.

[0028] In this invention, the metal bonding strength is obtained by testing according to the test method of GB / T 9286-2021 "Cross-cut test for paints and varnishes".

[0029] Preferably, the thickness of the washable photosensitive resin layer is 10-300 μm, such as 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, etc.

[0030] Preferably, when applied to a PCB board, the PCB board thickness is ≤0.5 mm, and the thickness of the washable photosensitive resin layer is 20-60 μm, such as 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, etc.; if 0.5 mm < PCB board thickness ≤ 1.5 mm, the thickness of the washable photosensitive resin layer is 61-100 μm, such as 61 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc.; if 1.5 mm < PCB board thickness ≤ 3 mm, the thickness of the washable photosensitive resin layer is 101-120 μm, such as 101 μm, 105 μm, 108 μm, 110 μm, 112 μm, 115 μm, 118 μm, 120 μm, etc. μm; PCB board thickness > 3 mm, the thickness of the washable photosensitive resin layer is 121-220 μm, such as 121 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, etc.

[0031] Preferably, by weight, the washable photosensitive resin layer comprises: 30-80 parts washable photosensitive resin, 1-10 parts photocuring agent, 0.1-5 parts processing aid and 5-30 parts filler.

[0032] In this invention, the washable photosensitive resin (30-80 parts) can be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, etc.; the photocuring agent (1-10 parts) can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.; the processing aid (0.1-5 parts) can be 0.1 parts, 0.5 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.; and the filler (5-30 parts) can be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc.

[0033] Preferably, the washable photosensitive resin contains any one or a combination of at least two of the following groups: amino, aldehyde, hydroxyl, carboxyl, amide, carbonyl, or ether.

[0034] When the washable photosensitive resin contains the above-mentioned groups, after UV curing, the film layer can be washed off in the film removal solution without leaving any film residue, thus affecting the PCB drilling pass rate.

[0035] Preferably, the washable photosensitive resin is a modified or unmodified acrylate resin, and more preferably includes modified or unmodified epoxy acrylate resin, modified or unmodified polyurethane acrylate resin, and modified or unmodified polyester acrylate resin.

[0036] Preferably, the processing aids include leveling agents and / or defoamers.

[0037] Preferably, the photocuring agent comprises any one or a combination of at least two of the following: a pyrolytic free radical photoinitiator, a hydrogen-abstracting free radical photoinitiator, or a cationic photoinitiator. More preferably, it comprises 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, methyl benzoylformate, and ethyl 2,4,6-trimethylbenzoyl-phenylphosphine. More preferably, it comprises any one or a combination of at least two of the following: 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexylphenyl ketone, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0038] Preferably, the filler comprises any one or a combination of at least two of talc, calcium carbonate, silica, barium sulfate, bentonite, or kaolin.

[0039] Preferably, the carrier film includes any one or a combination of at least two of BOPP film, PET film, PC film, EVA film or OPP film, with PET film being the most preferred.

[0040] Preferably, the thickness of the carrier membrane is 0.01-0.15 mm, such as 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, etc.

[0041] In this invention, the carrier film serves to support the washable photosensitive resin layer. The washable photosensitive resin loses its fluidity after surface drying, but cannot form a film before curing; therefore, a carrier film is necessary. If the carrier film is too thin, its load-bearing capacity is poor, which is detrimental to subsequent applications (such as bonding to PCB boards) and can easily affect production and the burr pass rate of PCB board drilling. If the carrier film is too thick, its bending resistance is poor and its cost is high.

[0042] Preferably, the adhesive film pad further includes a cover film located on the side of the washable photosensitive resin layer away from the carrier film layer.

[0043] Preferably, the thickness of the covering film is 0.01-0.15 mm, such as 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, etc.

[0044] Preferably, the release force between the cover film and the washable photosensitive resin layer is ≤100 g / in, such as 100 g / in, 80 g / in, 70 g / in, 60 g / in, 50 g / in, 40 g / in, 30 g / in, 20 g / in, 10 g / in, 5 g / in, 1 g / in, etc.

[0045] In this invention, the function of the cover film is to protect the washable photosensitive resin layer from contamination. It needs to be removed before application to the film pad. Therefore, it is required that the release force between the cover film and the washable photosensitive resin layer is small. If the release force is too large, it will easily affect the integrity of the washable photosensitive resin layer when removing the cover film. If its thickness is too small, the covering effect will be poor and it will be difficult to peel off the film. If its thickness is too large, the bending resistance will be poor and the cost will be high.

[0046] In this invention, the adhesive film pad is a semi-solid adhesive film, which can be stored and transported in form before application.

[0047] Preferably, the covering film includes any one or a combination of at least two of BOPP film, PET film, PC film, EVA film, OPP film or PE film, and preferably PET film.

[0048] like Figure 2 As shown, the structure of the adhesive film pad of the present invention includes a carrier film, a washable photosensitive resin layer and a cover film arranged in sequence.

[0049] Preferably, the method for preparing the adhesive film pad includes:

[0050] (1) The washable photosensitive resin composition is coated onto a carrier film and dried to form a washable photosensitive resin layer;

[0051] (2) An optional cover film is provided on the washable photosensitive resin layer to obtain the adhesive film pad.

[0052] In the preparation of the adhesive film pad of the present invention, the washable photosensitive resin layer only needs to be surface dry and lose its fluidity. In practical applications, it is necessary to use UV curing to form a film.

[0053] Preferably, the surface drying method includes baking, room temperature, etc. The present invention does not make specific limitations, and any method that can achieve surface drying without complete curing can be applied to the present invention.

[0054] Preferably, the coating method includes spraying, scraping, or roller coating, etc. The present invention will not limit the specific method further. Any method that can form a washable photosensitive resin layer can be applied to the present invention. The coating method of the present invention can be adjusted according to the viscosity of the washable photosensitive resin.

[0055] Preferably, the bonding temperature is greater than or equal to the softening temperature of the washable photosensitive resin layer, and is preferably 30-150℃, such as 30℃, 35℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 120℃, 130℃, 140℃, 150℃, etc.

[0056] In this invention, the bonding temperature must not be too high, otherwise the washable photosensitive resin layer will soften severely, enter the blind hole, and cause film residue.

[0057] Preferably, the bonding pressure is 0.5-10 kgf / cm². 2 For example, 0.5 kgf / cm 2 1 kgf / cm 2 2 kgf / cm 2 3 kgf / cm 2 4 kgf / cm 2 5 kgf / cm 2 6 kgf / cm 2 7 kgf / cm 2 8 kgf / cm 2 9 kgf / cm 2 10 kgf / cm 2 wait.

[0058] In this invention, if the bonding pressure is too low, the adhesion between the washable photosensitive resin layer and the lower surface of the PCB board will be poor, and it will easily fall off during drilling; if the bonding pressure is too high, the washable photosensitive resin layer will enter the blind hole, resulting in residual film.

[0059] Preferably, the curing method includes UV curing, and the UV curing energy is preferably 300-4000 mJ / cm². 2 For example, 300 mj / cm 2 500 mj / cm 2 800 mj / cm 2 1000 mj / cm 2 1500 mj / cm 2 2000 mj / cm 2 2500 mj / cm 2 3000 mj / cm 2 3500 mj / cm2 4000 mj / cm 2 wait.

[0060] If the curing energy is too low, it may result in incomplete curing, and the cured washable photosensitive resin layer will be soft and have poor adhesion to the underside of the PCB, which can easily lead to burrs during drilling. If the curing energy is too high, it may cause bubbles to appear in the washable photosensitive resin layer, which will also affect the burr suppression effect.

[0061] Preferably, the stripping solution used for stripping includes an alkaline stripping solution or water.

[0062] Preferably, the rinsing temperature includes 20-100℃, such as 20℃, 30℃, 40℃, 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, etc.

[0063] Preferably, the alkaline film-removing solution can be an organic alkaline solution and / or an inorganic alkaline solution, such as a sodium hydroxide solution. This invention does not impose specific limitations, and any alkaline film-removing solution or water capable of removing the film can be used in this invention. The water can be tap water.

[0064] The method for improving PCB board drilling described in this invention is applicable to any PCB board currently available, and is especially suitable for drilling PCB boards that have warped deformation or have height differences.

[0065] Preferably, the PCB board is pretreated before the washable photosensitive resin layer is bonded, which can increase the roughness of the lower surface of the PCB board, improve the bonding force between the washable photosensitive resin layer and the PCB board, and thus improve the application effect of the adhesive film pad.

[0066] Preferably, the pretreatment method includes any one or a combination of at least two of the following: water washing, grinding, pickling, medium roughening, ultra roughening, volcanic ash treatment, or browning.

[0067] Secondly, the present invention provides an application of the method described in the first aspect in the drilling of PCB boards.

[0068] Compared with the prior art, the present invention has the following beneficial effects:

[0069] The method for improving PCB drilling provided by this invention can suppress the risk of drilling burrs and achieve complete film removal without any film residue, which is beneficial to improving the quality of PCB drilling. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the PCB board structure before drilling, provided in an embodiment of the present invention;

[0071] Figure 2This is a schematic diagram of the structure of the adhesive film pad provided in the preparation example of the present invention;

[0072] Wherein: 1-Cover film; 2-Washable photosensitive resin layer; 3-Carrier film; 4-PCB board; 401-Blind hole; 5-Cureable washable photosensitive resin layer. Detailed Implementation

[0073] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0074] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art, and can be purchased from commercially available products. Some raw material information is as follows:

[0075] Carrier film: PET film, 0.1 mm thick, purchased from Shenzhen Yixin Electronics Co., Ltd.;

[0076] Covering film 1: PET film, 0.1 mm thick, release force 50 g / in, purchased from Huizhou Best Film Co., Ltd.

[0077] Covering film 2: PET film, thickness 0.05 mm, release force 20 g / in, purchased from Huizhou Best Film Co., Ltd.;

[0078] Covering film 3: PET film, 0.12 mm thick, release force 40 g / in, purchased from Huizhou Best Film Co., Ltd.

[0079] Modified epoxy acrylate resin 1: Nanxiong Ketian Chemical Co., Ltd., brand name 4421;

[0080] Modified epoxy acrylate resin 2: Guangdong Boxin New Material Technology Co., Ltd., brand name B-584;

[0081] Modified polyester acrylate resin 1: Guangdong Haohui New Materials Co., Ltd., brand name CR92284;

[0082] Modified polyester acrylate resin 2: Dongguan Lanka New Materials Co., Ltd., brand name WU9001;

[0083] UV curing agent: Guangdong Lankelu Polymer Materials Co., Ltd., brand name TPO;

[0084] Leveling agent: Dongguan Yichen Polymer Technology Co., Ltd., brand name 4331A;

[0085] Defoamer: Guangzhou Duomeiduo New Materials Co., Ltd., brand name BK-221;

[0086] Talc: Shenzhen Ocean Powder Technology Co., Ltd., brand name HY-TA05;

[0087] Calcium carbonate: Guangxi Junhui Polymer Technology Co., Ltd., grade 2000 mesh calcium carbonate;

[0088] Silica: Shenzhen Ocean Powder Technology Co., Ltd., brand name HY-G12.

[0089] Examples 1-4

[0090] This embodiment provides a method for improving PCB drilling, as follows:

[0091] S1. The lower surface of the PCB board is pickled using a 10% sulfuric acid solution;

[0092] S2. Remove the cover film from the adhesive film pad, attach the washable photosensitive resin layer to the lower surface of the PCB board, perform UV curing after bonding, and remove the carrier film after curing.

[0093] S3. Drill holes in the PCB board;

[0094] S4. After drilling, use tap water to wash away the photosensitive resin layer to complete the drilling.

[0095] In the method described, such as Figure 2 As shown, the adhesive film pad comprises a carrier film 3, a washable photosensitive resin layer 2, and a cover film 1 stacked sequentially, as detailed below:

[0096] Table 1

[0097]

[0098] The method for preparing the adhesive film pad is as follows:

[0099] (1) Prepare washable photosensitive resin according to the formulation amount of each component;

[0100] (2) Spray the washable photosensitive resin onto the carrier film and surface dry at 100℃ for 30 min to form a washable photosensitive resin layer.

[0101] (3) After cooling, a cover film is placed on the washable photosensitive resin layer to obtain the adhesive film pad.

[0102] Comparative Example 1

[0103] This comparative example provides a method for drilling holes in a PCB.

[0104] S1. Prepare a melamine pad (RYM, purchased from Shenzhen Liuxin Industrial Co., Ltd.), and fix the melamine pad with pins;

[0105] S2. Place the PCB board, drill holes, remove the board, and complete the drilling.

[0106] Comparative Example 2

[0107] This comparative example provides a method for drilling holes in a PCB.

[0108] The difference from Example 1 is that, in this comparative example, the adhesive film pad is replaced with PCB dry film, wherein the photosensitive adhesive layer is adhered to the lower surface of the PCB board.

[0109] Comparative Example 3

[0110] This comparative example provides a method for drilling holes in a PCB.

[0111] The drilling method provided in Example 1 of CN118475006A.

[0112] Performance testing

[0113] The samples involved in the methods provided in the embodiments and comparative examples were subjected to performance testing, and the methods are as follows:

[0114] (1) Hardness (after the washable photosensitive resin layer has been cured): The hardness was determined according to the test method of GB / T 6739-2022 "Determination of Hardness of Paint Film by Pencil Method".

[0115] (2) Metal bonding strength: Tested according to the test method of GB / T 9286-2021 "Paints and Varnishes Cross-cut Test";

[0116] (3) Drilling burrs: Drilling parameters: 0.35 mm, number of holes: 200, and the PCB boards are all 6 mm thick with a warping deformation range of 2 mm. The average value of drilling burrs after drilling is tested.

[0117] (4) Delamination residue rate: visual inspection.

[0118] The results are as follows:

[0119] Table 2

[0120]

[0121] As demonstrated by the embodiments and performance tests, the adhesive film pad provided by the present invention has high hardness when applied to PCB drilling and can suppress the risk of drilling burrs; it can also achieve complete film removal without any film removal residue, which is beneficial to improving the quality of PCB drilling.

[0122] The applicant declares that the technical solution of this invention is illustrated through the above embodiments, but this invention is not limited to the above process steps, that is, it does not mean that this invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A method for drilling holes in a PCB, characterized in that, The method includes: S1. Prepare an adhesive film pad, the adhesive film pad comprising a carrier film and a washable photosensitive resin layer arranged sequentially; S2. The washable photosensitive resin layer included in the adhesive film pad is attached to the lower surface of the PCB board and cured. After curing, the carrier film is removed. S3. Drill holes in the PCB board; S4. After drilling, wash off the washable photosensitive resin layer.

2. The method according to claim 1, characterized in that, The softening temperature of the washable photosensitive resin layer after surface drying is ≥30℃; Preferably, the hardness of the washable photosensitive resin layer after UV curing is ≥5 B; Preferably, the metal adhesion of the washable photosensitive resin layer is ≤ level 2; Preferably, the thickness of the washable photosensitive resin layer is 10-300 μm.

3. The method according to claim 1 or 2, characterized in that, By weight, the washable photosensitive resin layer comprises: 30-80 parts washable photosensitive resin, 1-10 parts photocuring agent, 0.1-5 parts processing aid and 5-30 parts filler.

4. The method according to claim 3, characterized in that, The washable photosensitive resin contains any one or a combination of at least two of the following groups: amino, aldehyde, hydroxyl, carboxyl, amide, carbonyl, or ether. Preferably, the washable photosensitive resin is a modified or unmodified acrylate resin, and more preferably includes modified or unmodified epoxy acrylate resin, modified or unmodified polyurethane acrylate resin, and modified or unmodified polyester acrylate resin. Preferably, the processing aids include leveling agents and / or defoamers; Preferably, the filler comprises any one or a combination of at least two of talc, calcium carbonate, silica, barium sulfate, bentonite, or kaolin.

5. The method according to any one of claims 1-4, characterized in that, The carrier film includes any one of BOPP film, PET film, PC film, EVA film or OPP film, preferably PET film; Preferably, the thickness of the carrier membrane is 0.01-0.15 mm.

6. The method according to any one of claims 1-5, characterized in that, The adhesive film pad also includes a cover film, which is located on the side of the washable photosensitive resin layer away from the carrier film; Preferably, the thickness of the covering film is 0.01-0.15 mm; Preferably, the release force between the cover film and the washable photosensitive resin layer is ≤100 g / in; Preferably, the covering film includes any one or a combination of at least two of BOPP film, PET film, PC film, EVA film, OPP film or PE film, and preferably PET film.

7. The method according to any one of claims 1-6, characterized in that, The method for preparing the adhesive film pad includes: (1) The washable photosensitive resin composition is coated onto a carrier film and dried to form a washable photosensitive resin layer; (2) An optional cover film is disposed on the washable photosensitive resin layer to obtain the adhesive film pad.

8. The method according to any one of claims 1-7, characterized in that, The bonding temperature is greater than or equal to the softening temperature of the washable photosensitive resin layer, preferably 30-150℃, and the preferred pressure is 0.5-10 kgf / cm². 2 ; Preferably, the curing method includes UV curing, and the UV curing energy is preferably 300-4000 mJ / cm². 2 .

9. The method according to any one of claims 1-8, characterized in that, The stripping solution used for stripping includes an alkaline stripping solution or water.

10. The application of the method as described in any one of claims 1-9 in improving PCB board drilling.

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