Control method for improving quality of slice holes

Abstract

The invention relates to the technical field of circuit board slicing, and particularly discloses a control method for improving slice hole quality, which comprises the following steps: preparing a high Tg prepreg matched with a slice hole in size according to the size of the slice hole to be filled, and filling the slice hole by using the high Tg prepreg to enable the high Tg prepreg to be flush with the surface of a line-in-line board, by utilizing the heat resistance of the high-Tg prepreg, multiple lamination can be carried out, and after actual operation verification, the laminated surface condition is not bad, an electroplated product board does not have bubbles and local layering, the problem of liquid medicine permeation is not found after electroplating, the process manufacturing is not influenced, and the production quality of the circuit board is effectively improved; the size of the high-Tg prepreg is matched with the size of the to-be-filled slice hole, and only the high-Tg prepreg needs to be plugged into the slice hole during filling, so that the operation is simple, and the filling convenience of the high-Tg prepreg and the slice hole is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of circuit board slicing, and in particular relates to a control method for improving the quality of slicing holes. Background Art

[0002] In the production of circuit boards, in order to monitor the quality of laminated dielectric thickness, plated through holes, blind holes, etc., slicing monitoring will be carried out in the corresponding process during the production process to ensure the quality of the produced circuit boards. The current way to slice circuit boards is to first cut a small piece (usually the sample size is 15mm*10mm) from a large piece of circuit board containing plated holes, blind holes, etc., and then fix and slice the sample. Finally, the sliced ​​sample is observed under a mirror microscope for a series of qualities such as laminated dielectric thickness, copper thickness of through holes and blind holes, aperture, hole type, etc., so that process problems and quality problems can be followed up, handled and improved in a timely manner.

[0003] In order to improve the quality of circuit board production, according to the product stacking structure, multiple pressings are required during the product manufacturing process. After each pressing, key processes need to be sliced ​​for quality monitoring. In order to reduce the impact on the subsequent quality of the product, the inner layer of the production board that has been sliced ​​must be filled during lamination, otherwise it will not be able to fill such a large slice hole with the semi-cured sheet of the current layer alone.

[0004] At present, most of the slice lamination filling methods use ordinary FR4 materials for manual filling. However, the heat resistance of ordinary FR4 materials is relatively poor. After multiple pressings, there will be delamination and bubbles. It will be damaged during the electroplating process, causing board quality problems. Therefore, we need to propose a control method for improving the quality of slice holes to solve the above problems, so that it can effectively improve the quality of the board surface. Summary of the invention

[0005] The purpose of the present invention is to provide a control method for improving the quality of slice holes. By using a high Tg semi-cured sheet to fill the slice holes, multiple laminations can be performed, and after actual operation verification, the laminated surface condition is not defective. After electroplating, the product board has no bubbles or local stratification, and no problem of drug seepage is found after electroplating, which effectively improves the production quality of the circuit board to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A control method for improving the quality of slice holes comprises the following steps:

[0008] S1, preparing a high Tg prepreg that matches the size of the slice hole to be filled;

[0009] S2. Manually fill the high Tg prepreg into the slicing hole during lamination layout, so that the surface of the high Tg prepreg is flush with the surface of the circuit layer;

[0010] S3. Laminate the circuit board filled with high Tg prepreg to confirm the quality of the product surface after lamination;

[0011] S4. Electroplate the qualified products after lamination, and select samples of the electroplated products for slicing to confirm the quality of the electroplating.

[0012] Preferably, the preparation process of the high Tg prepreg is as follows:

[0013] A1. Using bismaleimide diphenylmethane and cyanate resin as main raw materials to prepare base resin glue;

[0014] A2. Prepare a mixture with filler, flame retardant, solvent and coupling agent as main raw materials;

[0015] A3, melting the matrix resin glue and adding the mixture into a sand mill, then adding a catalyst into the sand mill for sand grinding to prepare a prepreg;

[0016] A4, using fiber reinforcement material to coat or impregnate prepreg, and then baking to obtain a prepreg;

[0017] A5. Cut the prepreg into high Tg prepregs that match the size of the slice holes.

[0018] Preferably, in step A1, when preparing the matrix resin glue, bismaleimide diphenylmethane and bisphenol A cyanate raw materials are added into a reaction container, and heated and stirred at a temperature of 50-170° C., and the stirring is continued for 10-200 minutes.

[0019] Preferably, in step A2, the filler is set to be one of silicon dioxide, magnesium hydroxide, graphite oxide, kaolin and hollow glass microspheres.

[0020] Preferably, the solvent is set to be one of acetone, butanone and N,N-dimethylformamide, and the coupling agent is set to be one of a silane coupling agent, a titanate coupling agent and an aluminate coupling agent.

[0021] Preferably, when preparing the mixture, filler, flame retardant, solvent and coupling agent are sequentially added into a reaction container containing matrix resin glue for mixing and stirring, the stirring speed is controlled at 100-600 r / min, and the stirring time is 0.5-24 hours.

[0022] Preferably, in step A3, the catalyst is set to be one of benzoyl peroxide, N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine and N-methylpiperidine.

[0023] Preferably, when preparing the prepreg, the matrix resin glue is melted and then added into a sand mill together with the mixture and the catalyst for sand grinding, and then the prepreg is obtained by rotary shearing with a high-speed shearing machine, wherein the melting temperature is 50-200°C, the sand grinding speed is 1000-6000r / min, and the rotary shear speed is 100-500r / min.

[0024] Preferably, in step A4, the fibrous reinforcement material is set to be one of glass fiber, carbon fiber and aramid fiber, and the baking temperature of the coated or impregnated fibrous reinforcement material is 90-200° C. and the baking time is 5-30 minutes.

[0025] Preferably, in step S3, when laminating the circuit layer filled with the high Tg prepreg, the circuit layer containing the high Tg prepreg and other circuit layers are first stacked together in sequence, and a vacuum laminator is used for lamination. The temperature during lamination is set at 180-200°C and the pressure is 15-35kg / cm 3 After lamination, the product is cooled. If there are no bubbles, damage or delamination on the surface of the product after lamination, it is a qualified product. If there are one or more of bubbles, damage and delamination on the surface of the product, it is an unqualified product.

[0026] The control method for improving the quality of slice holes proposed in the present invention has the following advantages compared with the prior art:

[0027] 1. The present invention uses a high Tg prepreg to fill the slice hole so that the high Tg prepreg is flush with the surface of the circuit board. The heat resistance of the high Tg prepreg is utilized to perform multiple laminations. The laminated surface condition is good after actual operation verification. The electroplated product board has no bubbles or local delamination. No seepage of chemical solution is found after electroplating, which does not affect the manufacturing process and effectively improves the production quality of the circuit board.

[0028] 2. The present invention matches the size of the high Tg prepreg with the size of the slicing hole to be filled. When filling, the high Tg prepreg only needs to be inserted into the slicing hole, which is easy to operate and improves the convenience of filling the high Tg prepreg with the slicing hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of the present invention;

[0030] Figure 2The flowchart of the preparation process of the high Tg prepreg of the present invention is as follows;

[0031] Figure 3 Comparison chart of filler materials used for embodiments of the present invention;

[0032] Figure 4 This is a quality confirmation comparison chart of using high Tg prepreg and ordinary FR4 material to fill the slice holes of the layer board respectively;

[0033] Figure 5 This is a statistical chart of defective rate for quality control of circuit boards using common FR4 materials to fill slice holes;

[0034] Figure 6 This is a statistical chart of the defective rate of circuit boards controlled by filling the slice holes with high Tg prepreg. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] The present invention provides Figure 1-2 A control method for improving the quality of slice holes shown in the figure comprises the following steps:

[0038] S1, preparing a high Tg prepreg that matches the size of the slice hole to be filled;

[0039] The preparation process of the high Tg prepreg is as follows:

[0040] A1. Using bismaleimide diphenylmethane and cyanate resin as main raw materials to prepare base resin glue;

[0041] When preparing the matrix resin glue, bismaleimide diphenylmethane and bisphenol A type cyanate raw materials are added into a reaction container, and heated and stirred at a temperature of 50-170°C, and stirred continuously for 10-200 minutes to ensure the uniformity of the mixture, and ensure that the resin and other additives can be fully integrated to form a uniform glue. After each addition of new components, stirring is required to be continued for 10-200 minutes to ensure the uniformity of the mixture. Bismaleimide and cyanate resins are used to increase the thermal stability and mechanical properties of the high Tg semi-cured sheet.

[0042] A2. A mixture is prepared with filler, flame retardant, solvent and coupling agent as main raw materials; by mixing the mixture with base resin glue, not only the physical properties of the resin, such as its flame retardancy and mechanical strength, are improved, but also the process properties, such as viscosity and film-forming property, are optimized.

[0043] The filler is one of silicon dioxide, magnesium hydroxide, graphite oxide, kaolin and hollow glass microspheres.

[0044] The flame retardant is set to be one of a magnesium flame retardant, a boron zinc flame retardant, a molybdenum tin flame retardant and a bromine flame retardant, wherein the magnesium flame retardant mainly includes magnesium hydroxide and magnesium salt whiskers, the boron zinc flame retardant includes zinc borate and ultrafine zinc borate, the molybdenum tin flame retardant includes melamine molybdate and quaternary ammonium octamolybdate, and the bromine flame retardant includes decabromodiphenyl ether and tetrabromobisphenol A. The flame retardant is used to increase the flame retardant effect of the semi-cured sheet.

[0045] The solvent is set to be one of acetone, butanone and N,N-dimethylformamide, and the coupling agent is set to be one of silane coupling agent, titanate coupling agent and aluminate coupling agent.

[0046] When preparing the mixture, filler, flame retardant, solvent and coupling agent are sequentially added into a reaction vessel containing matrix resin glue for mixing and stirring. The stirring speed is controlled at 100-600r / min and the stirring time is 0.5-24 hours to ensure that all ingredients are evenly dispersed and completely wet the reinforcing fibers.

[0047] A3, melting the matrix resin glue and adding the mixture into a sand mill, then adding a catalyst into the sand mill for sand grinding to prepare a prepreg;

[0048] The catalyst is set to be one of benzoyl peroxide, N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine and N-methylpiperidine.

[0049] When preparing the prepreg, the matrix resin glue is melted and then added into a sand mill together with the mixture and the catalyst for sand milling, and then the prepreg is obtained by rotary shearing with a high-speed shearing machine, wherein the melting temperature is 50-200°C, the sand milling speed is 1000-6000r / min, and the rotary shearing speed is 100-500r / min.

[0050] A4, using fiber reinforcement material to coat or impregnate prepreg, and then baking to obtain a prepreg;

[0051] The fibrous reinforcement material is set to be one of glass fiber, carbon fiber and aramid fiber. The baking temperature of the coated or impregnated fibrous reinforcement material is 90-200° C. and the baking time is 5-30 minutes.

[0052] A5. Cut the prepreg into high Tg prepregs that match the size of the slice holes.

[0053] S2. Manually fill the high Tg prepreg into the slicing hole during lamination layout, so that the surface of the high Tg prepreg is flush with the surface of the circuit layer;

[0054] The size of the high Tg prepreg is matched with the size of the slicing hole to be filled. When filling, the high Tg prepreg only needs to be inserted into the slicing hole. The operation is simple, which improves the convenience of filling the high Tg prepreg with the slicing hole.

[0055] S3. Laminate the circuit board filled with high Tg prepreg to confirm the quality of the product surface after lamination;

[0056] When laminating the circuit layer filled with high Tg prepreg, first stack the circuit layer containing high Tg prepreg with other circuit layers in order, and use a vacuum laminator for lamination. The temperature during lamination is set at 180-200℃ and the pressure is 15-35kg / cm 3 After lamination, the product is cooled. If there are no bubbles, damage or delamination on the surface of the product after lamination, it is a qualified product. If there are one or more of bubbles, damage and delamination on the surface of the product, it is an unqualified product.

[0057] S4. Electroplate the qualified products after lamination, and select samples of the electroplated products for slicing to confirm the quality of the electroplating;

[0058] High Tg prepreg is made of treated electronic grade glass fiber cloth impregnated with epoxy resin glue, and the resin enters a semi-cured state (B stage) after heat treatment (pre-baking); high Tg prepreg will soften under heating and pressure, and solidify after cooling, providing the inner and outer insulating medium of the multilayer board, controlling the accuracy of the characteristic impedance, and ensuring the performance of the multilayer board circuit. The Tg value is the temperature critical point where the amorphous polymer transforms into a highly elastic state. High Tg means that the board can maintain stable physical properties under high temperature conditions and is not prone to deformation, fracture and other problems.

[0059] By using high Tg prepreg to fill the slice holes, the high Tg prepreg is flush with the surface of the circuit board. By utilizing the heat resistance of the high Tg prepreg, multiple laminations can be performed. After actual operation verification, the laminated surface condition is good. There are no bubbles or local delamination on the electroplated product boards. No problem of drug seepage was found after electroplating, which does not affect the production process and effectively improves the production quality of the circuit board.

[0060] Example 2

[0061] The method provided in Example 1 was used for actual production verification, and compared with the method of using ordinary FR4 material to fill the slice holes and then laminarize to confirm the effectiveness of the improvement provided in Example 1. Figure 3-5 As shown, the verification results are as follows:

[0062] 1. Select high Tg prepreg and ordinary FR4 material with the same size as the slice hole, such as Figure 3 As shown, the group using high Tg prepreg is named as the experimental group, and the group using ordinary FR4 material is named as the control group.

[0063] 2. Fill the high Tg prepreg and ordinary FR4 material into the slice holes of the layer board respectively, and perform lamination and electroplating confirmation, such as Figure 4 As shown, the confirmation results are as follows:

[0064] Experimental group: By using Tg semi-cured sheet to fill the slice holes, there are no bubbles and delamination on the board surface after lamination, and there is no damage or serious contamination on the board surface after electroplating.

[0065] Comparative group: By using ordinary FR4 material to fill the slice holes, different degrees of delamination and bubbles appeared on the board surface after lamination, and the board surface was seriously contaminated;

[0066] 3. If Figure 5 The figure shows the quality control of circuit boards using ordinary FR4 materials to fill slice holes throughout 2022. The average inner layer open circuit defect rate of the circuit boards produced was 2.87%, the average inner layer short circuit defect rate was 2.66%, and the average gap defect rate was 1.9%. Figure 6 In 2023, Zhongwei will use high Tg semi-cured sheets to fill the slicing holes to control the circuit boards. The average inner layer open circuit defect rate of circuit board production is about 1.87%, the average inner layer short circuit defect rate is about 1.66%, and the average notch defect rate is about 0.9%. Through batch verification throughout the year, it is known that the use of high Tg semi-cured sheets to fill the slicing holes has improved the quality yield of circuit board production.

[0067] Therefore, by using high Tg semi-cured sheet to fill the slice holes, there is no defect in the lamination surface condition of the circuit board during lamination. There are no bubbles or local delamination on the electroplated circuit board. There is no problem of drug seepage after electroplating, which does not affect the production process and effectively improves the production quality of the circuit board.

[0068] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A control method for improving the quality of slice holes, characterized in that: The steps include: S1, preparing a high Tg prepreg that matches the size of the slice hole to be filled; S2. Manually fill the high Tg prepreg into the slicing hole during lamination layout, so that the surface of the high Tg prepreg is flush with the surface of the circuit layer; S3. Laminate the circuit board filled with high Tg prepreg to confirm the quality of the product surface after lamination; S4. Electroplate the qualified products after lamination, and select samples of the electroplated products for slicing to confirm the quality of the electroplating.

2. A control method for improving the quality of slice holes according to claim 1, characterized in that: The preparation process of the high Tg prepreg is as follows: A1. Using bismaleimide diphenylmethane and cyanate resin as main raw materials to prepare base resin glue; A2. Prepare a mixture with filler, flame retardant, solvent and coupling agent as main raw materials; A3, melting the matrix resin glue and adding the mixture into a sand mill, then adding a catalyst into the sand mill for sand grinding to prepare a prepreg; A4, using fiber reinforcement material to coat or impregnate prepreg, and then baking to obtain a prepreg; A5. Cut the prepreg into high Tg prepregs that match the size of the slice holes.

3. A control method for improving the quality of slice holes according to claim 2, characterized in that: In step A1, when preparing the matrix resin glue, bismaleimide diphenylmethane and bisphenol A cyanate are added into a reaction container, and heated and stirred at a temperature of 50-170° C. for 10-200 minutes.

4. A control method for improving the quality of slicing holes according to claim 3, characterized in that: In step A2, the filler is set to be one of silicon dioxide, magnesium hydroxide, graphite oxide, kaolin and hollow glass microspheres.

5. A control method for improving the quality of slice holes according to claim 4, characterized in that: The solvent is set to be one of acetone, butanone and N,N-dimethylformamide, and the coupling agent is set to be one of silane coupling agent, titanate coupling agent and aluminate coupling agent.

6. A control method for improving the quality of slice holes according to claim 5, characterized in that: When preparing the mixture, filler, flame retardant, solvent and coupling agent are sequentially added into a reaction container containing matrix resin glue for mixing and stirring. The stirring speed is controlled at 100-600 r / min and the stirring time is 0.5-24 hours.

7. A control method for improving the quality of slice holes according to claim 6, characterized in that: In step A3, the catalyst is set to be one of benzoyl peroxide, N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine and N-methylpiperidine.

8. A control method for improving the quality of slice holes according to claim 7, characterized in that: When preparing the prepreg, the matrix resin glue is melted and then added into a sand mill together with the mixture and the catalyst for sand milling, and then the prepreg is obtained by rotary shearing with a high-speed shearing machine, wherein the melting temperature is 50-200°C, the sand milling speed is 1000-6000r / min, and the rotary shearing speed is 100-500r / min.

9. A control method for improving the quality of slice holes according to claim 8, characterized in that: In step A4, the fibrous reinforcement material is set to be one of glass fiber, carbon fiber and aramid fiber, and the baking temperature of the coated or impregnated fibrous reinforcement material is 90-200° C. and the baking time is 5-30 minutes.

10. A control method for improving the quality of slice holes according to claim 9, characterized in that: In step S3, when laminating the circuit layer filled with the high Tg prepreg, the circuit layer containing the high Tg prepreg and other circuit layers are first stacked together in order, and a vacuum laminator is used for lamination. The temperature during lamination is set at 180-200°C and the pressure is 15-35kg / cm 3 After lamination, the product is cooled. If there are no bubbles, damage or delamination on the surface of the product after lamination, it is a qualified product. If there are one or more of bubbles, damage and delamination on the surface of the product, it is an unqualified product.

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