WO-2026091379-A1 - CONTROL METHOD FOR IMPROVING QUALITY OF CROSS-SECTIONAL HOLE

WO2026091379A1WO 2026091379 A1WO2026091379 A1WO 2026091379A1WO-2026091379-A1

Abstract

A control method for improving the quality of a cross-sectional hole, the control method comprising: first preparing, on the basis of the size of a cross-sectional hole to be filled, a high-Tg prepreg matching the cross-sectional hole in terms of size, and filling the cross-sectional hole with the high-Tg prepreg, such that a surface of the high-Tg prepreg is flush with a surface of a circuit board. Multiple laminations can be performed by using the heat resistance of the high-Tg prepreg; after actual operation verification, the condition of a laminated surface is not defective, and no bubbles or local delamination occur on an electroplated product board; and after electroplating, the problem of liquid medicine seepage does not occur, so that the manufacturing process is not affected, and the production quality of the circuit board is effectively improved. By means of matching the size of the high-Tg prepreg with that of the cross-sectional hole to be filled, only the high-Tg prepreg needs to be plugged into the cross-sectional hole during filling, so that operation is simple, and the convenience of filling the cross-sectional hole with the high-Tg prepreg is improved.

Inventors

CHEN, XIAOFENG
JIANG, XINHUA
MA, Gonghui
SHEN, WEIJUN

Assignees

上海美维电子有限公司

Dates

Publication Date: 20260507
Application Date: 20250314
Priority Date: 20241029

Claims (10)

A method for improving the quality of sliced holes, characterized by comprising the following steps: S1. Prepare a high-Tg prepreg that matches the size of the slicing holes according to the size of the holes to be filled; S2. When laminating and laying out the substrate, manually fill the cutting holes with the high Tg prepreg to make the surface of the high Tg prepreg flush with the surface of the circuit board. S3. Laminate the circuit board filled with high Tg prepreg and confirm the surface quality of the product after lamination. S4. Electroplating is performed on qualified products after lamination. Samples of the electroplated products are selected for cross-sectioning to confirm the quality of the electroplating.
According to claim 1, the method for controlling the quality of slicing holes is characterized in that the preparation process of the high Tg prepreg is as follows: A1. A matrix resin solution was prepared using bismaleimide diphenylmethane and cyanate ester resin as the main raw materials. A2. A mixture is prepared using fillers, flame retardants, solvents, and coupling agents as the main raw materials; A3. After melting the matrix resin liquid, add it to the sand mill along with the mixture, and then add the catalyst to the sand mill for sand milling to prepare the preimpregnation solution; A4. Apply or impregnate the prepreg with fiber-reinforced material, and then bake it to obtain a semi-cured sheet. A5. Cut the prepreg into high Tg prepregs that match the size of the cut hole.
According to claim 2, the method for improving the quality of sliced pores is characterized in that: in step A1, when preparing the matrix resin solution, bismaleimide diphenylmethane and bisphenol A cyanate raw materials are added to the reaction vessel and heated and stirred at a temperature of 50-170°C for 10-200 minutes.
According to claim 3, the method for improving the quality of sliced pores is characterized in that: in step A2, the filler is selected from silicon dioxide, magnesium hydroxide, graphite oxide, kaolin, and hollow glass microspheres.
According to claim 4, the method for improving the quality of sliced pores is characterized in that: the solvent is one of acetone, butanone, and N,N-dimethylformamide, and the coupling agent is one of silane coupling agent, titanate coupling agent, and aluminate coupling agent.
According to claim 5, a method for improving the quality of sliced pores is characterized in that: during the preparation of the mixture, filler, flame retardant, solvent and coupling agent are sequentially added to a reaction vessel containing matrix resin liquid for mixing and stirring, the stirring speed is controlled at 100-600 r/min and the stirring time is 0.5-24 hours.
According to claim 6, the method for improving the quality of sliced pores is characterized in that: in step A3, the catalyst is set as one of benzoyl peroxide, N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, pyridine, quinoline, N-methylmorpholine, triethanolamine, triethylenediamine, and N-methylpiperidine.
According to claim 7, a method for controlling the quality of sliced holes is characterized in that: when the preimpregnating liquid is prepared, the matrix resin liquid is melted and then added to a sand mill along with the mixture and catalyst for sand milling, and then the preimpregnating liquid is obtained by rotary shearing by a high-speed shearing machine, wherein the melting temperature is 50-200℃, the sand milling speed is 1000-6000r/min, and the rotary shearing speed is 100-500r/min.
According to claim 8, the method for improving the quality of slicing holes is characterized in that: in step A4, the fibrous reinforcing material is set as one of glass fiber, carbon fiber and aramid fiber, and the baking temperature of the coated or impregnated fibrous reinforcing material is 90-200℃ and the baking time is 5-30 minutes.
According to claim 9, a method for improving the quality of sliced holes is characterized in that: in step S3, when laminating the circuit board filled with high Tg prepreg, the circuit board containing high Tg prepreg is first stacked with other circuit boards in sequence, and then laminated using a vacuum laminator. The temperature during lamination is set at 180-200℃, and the pressure is 15-35 kg/ cm3 . After lamination, the product is cooled. Products without bubbles, damage, or delamination on the surface are considered qualified products, while products with bubbles, damage, or delamination on the surface are considered unqualified products.

Description

A method for improving the quality of sliced holes Technical Field This invention belongs to the field of circuit board slicing technology, and specifically relates to a control method for improving the quality of sliced holes. Background Technology In PCB manufacturing, to monitor the quality of laminated dielectric thickness, plated vias, and blind vias, slicing monitoring is performed at relevant stages to ensure the quality of the produced PCBs. Currently, the method for PCB slicing involves first cutting a small piece (typically 15mm x 10mm) containing plated vias and blind vias from a large sheet of PCB. This sample is then fixed and sliced. Finally, the sliced sample is observed under a mirror microscope to examine a range of quality parameters, including laminated dielectric thickness, copper thickness of vias and blind vias, hole diameter, and hole shape. This allows for timely follow-up, handling, and improvement of any process or quality issues. To improve the quality of circuit board production, the product stacking process requires multiple laminations. After each lamination, key processes require slicing for quality monitoring. To reduce the impact on subsequent product quality, the production boards with sliced inner layers must be filled during lamination; otherwise, the semi-cured sheets of the current layer cannot fill such large slicing holes. Currently, most methods for laminating and filling slices use ordinary FR4 material for manual filling. However, ordinary FR4 material has poor heat resistance, and after multiple laminations, delamination and bubbles may occur. It may also break during the electroplating process, causing board quality problems. Therefore, we need to propose a method to improve the control of slice hole quality to solve the above-mentioned problems and effectively improve the board quality. Summary of the Invention The purpose of this invention is to provide a method for improving the quality of sliced holes. By using high Tg prepreg to fill the sliced holes, multiple laminations can be performed. After actual operation verification, the surface condition of the laminated product is unblemished. No bubbles or local delamination are found in the electroplated product boards, and no chemical seepage problem is found after electroplating. This effectively improves the production quality of circuit boards and solves the problems mentioned in the background art. To achieve the above objectives, the present invention adopts the following technical solution: A method for improving the quality of sliced wells includes the following steps: S1. Prepare a high-Tg prepreg that matches the size of the slicing holes according to the size of the holes to be filled; S2. When laminating and laying out the substrate, manually fill the cutting holes with the high Tg prepreg to make the surface of the high Tg prepreg flush with the surface of the circuit board. S3. Laminate the circuit board filled with high Tg prepreg and confirm the surface quality of the product after lamination. S4. Electroplating is performed on qualified products after lamination. Samples of the electroplated products are selected for cross-sectioning to confirm the quality of the electroplating. Preferably, the preparation process of the high Tg prepreg is as follows: A1. A matrix resin solution was prepared using bismaleimide diphenylmethane and cyanate ester resin as the main raw materials. A2. A mixture is prepared using fillers, flame retardants, solvents, and coupling agents as the main raw materials; A3. After melting the matrix resin liquid, add it to the sand mill along with the mixture, and then add the catalyst to the sand mill for sand milling to prepare the preimpregnation solution; A4. Apply or impregnate the prepreg with fiber-reinforced material, and then bake it to obtain a semi-cured sheet. A5. Cut the prepreg into high Tg prepregs that match the size of the cut hole. Preferably, in step A1, the matrix resin solution is prepared by adding bismaleimide diphenylmethane and bisphenol A cyanate raw materials into a reaction vessel and heating and stirring at a temperature of 50-170°C for 10-200 minutes. Preferably, in step A2, the filler is selected from silicon dioxide, magnesium hydroxide, graphite oxide, kaolin, and hollow glass microspheres. Preferably, the solvent is one of acetone, butanone, and N,N-dimethylformamide, and the coupling agent is one of silane coupling agent, titanate coupling agent, and aluminate coupling agent. Preferably, during the preparation of the mixture, the filler, flame retardant, solvent and coupling agent are sequentially added to a reaction vessel containing a matrix resin solution for mixing and stirring. The stirring speed is controlled at 100-600 r/min and the stirring time is 0.5-24 hours. Preferably, in step A3, the catalyst is selected from benzoyl peroxide, N,N-dimethylbenzylamine, N,N-dimethylaniline, N,N-dimethyltoluidine, pyridine, quinoline, N-methylmorph