CN111065207B - Method for processing poor back-drilled board of PCB - Google Patents
Method for processing poor back-drilled board of PCB Download PDFInfo
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- CN111065207B CN111065207B CN201911417957.5A CN201911417957A CN111065207B CN 111065207 B CN111065207 B CN 111065207B CN 201911417957 A CN201911417957 A CN 201911417957A CN 111065207 B CN111065207 B CN 111065207B
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- pcb
- drilling
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- back drilling
- drill
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0011—Working of insulating substrates or insulating layers
- H05K3/0044—Mechanical working of the substrate, e.g. drilling or punching
- H05K3/0047—Drilling of holes
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/0094—Filling or covering plated through-holes or blind plated vias, e.g. for masking or for mechanical reinforcement
Abstract
The invention provides a method for processing a poor back-drilled board of a PCB, which comprises the following steps: manufacturing a back drilling belt, and performing back drilling processing on the PCB to form a back drilling hole; measuring the thickness of the PCB circuit board in the area of the back drilling hole, screening out a board with the thickness smaller than a standard value as a bad board, measuring the thicknesses of other areas of the bad board, and selecting the area with the board thickness meeting the standard value as a drill repairing area; manufacturing a drill repairing belt, and performing drill repairing on the selected drill repairing area, wherein the drilling depth of the drill repairing belt is greater than that of the back drilling belt, so as to form a new back drilling hole; electroplating a tin coating on both the original back drilled hole and the new back drilled hole by an electroplating process; carrying out etching process treatment on the PCB; and after the etching process is finished, carrying out tin removal treatment to expose the residual copper piles in the two back drilled holes. The new back drilling hole is prevented from being affected by the tin coating, and the length of the residual copper pile meets the requirement of the finished PCB on the residual copper pile.
Description
Technical Field
The invention belongs to the field of PCB manufacturing, and particularly relates to a method for processing a back-drilled bad PCB of a PCB.
Background
The PCB is also called a printed circuit board or a printed circuit board, and is an important electronic component, which is a support for electronic components and is a carrier for electrical connection of electronic components.
In the manufacturing process of the PCB, back drilling treatment is carried out on the PCB according to product requirements. Due to the fact that the PCB is prone to generating size errors in the pressing process, the drilling depth of the back drill cannot reach the standard, and etching amount of the copper column in the subsequent etching process is further affected. When the copper pillar is etched too much and the residual copper stud is too short, there is a risk of opening the circuit board of the PCB.
Disclosure of Invention
The invention is realized by the following technical scheme:
a method for processing a PCB back drilling defective board comprises the following steps:
s1, back drilling, namely manufacturing a back drilling belt, and performing back drilling processing on the PCB to form a back drilling hole;
s2, measuring, namely measuring the thickness of the PCB circuit board in the area where the back drilling hole is located, screening out a board with the thickness smaller than a standard value as a defective board, measuring the thicknesses of other areas of the defective board, and selecting the area with the board thickness meeting the standard value as a drill repairing area;
s3, drilling compensation, namely manufacturing a drilling compensation belt, and performing drilling compensation in the drilling compensation area selected in the step S2, wherein the drilling depth of the drilling compensation belt is larger than that of the back drilling belt, so as to form a new back drilling hole;
s4, plating tin, namely plating a tin plating layer in the original back drilled hole and the new back drilled hole through an electroplating process;
s5, etching, namely, etching the PCB;
and S6, stripping tin, wherein after the etching process in the step S5 is finished, the tin stripping treatment is carried out to expose the residual copper piles in the two back drilled holes.
Further, in the step S3, the rotation speed of the drill-back belt is the same as the rotation speed of the drill-back belt.
Further, in the step S3, the drilling depth of the drill back strip is 50 μm greater than that of the drill back strip.
Further, in the step S3, the tool type of the drill repairing belt is selected according to the thickness of the drill repairing area of the PCB circuit board measured in the step S2.
Furthermore, before the tin plating process of the step S4 is carried out, a micro-etching process is firstly carried out to form a surrounding rough surface on the copper surface, so that the adhesion is enhanced.
Further, the PCB circuit board in the step S5 is patterned by an exposure method, and the process flow thereof is as follows: cutting, coating, drying, exposing, developing, drying, etching and demolding.
Further, the PCB in the step S5 is patterned by a screen printing method, and the process flow thereof is as follows: cutting, screen printing, etching and demolding.
Further, the tin stripping process in the step S6 is to soak the PCB in the leaching agent and heat the PCB to 60 ℃.
Further, the leaching agent is nitric acid-sodium sulfamate-pyrrolidone-ferric trichloride solution.
Further, in the step S4, the tin plating layer has a thickness of 4 to 6 μm.
Through the scheme, the invention at least obtains the following technical effects: the method has the advantages that the back drilling is carried out on the PCB with poor back drilling to form a new back drilling hole, the original back drilling hole is protected by the tin coating, and the problem that the PCB is opened due to the fact that the residual copper pile is too short because the residual copper pile in the original back drilling hole is corroded in the etching process is solved. And the new back drilling hole is drilled under the standard board thickness, and the length of the residual copper pile consumed by etching in the original process is replaced by the deeper drilling depth during drilling compensation, so that the new back drilling hole is free from the influence of a tin coating, and the length of the residual copper pile meets the requirement of a finished product PCB (printed circuit board) on the residual copper pile.
Detailed Description
The present invention will be further described with reference to the following examples.
Example 1:
a method for processing a PCB back drilling defective board comprises the following steps:
s1, back drilling, namely manufacturing a back drilling belt, and performing back drilling processing on the PCB to form a back drilling hole;
s2, measuring, namely measuring the thickness of the PCB circuit board in the area where the back drilling hole is located, screening out a board with the thickness smaller than a standard value as a defective board, measuring the thicknesses of other areas of the defective board, and selecting the area with the board thickness meeting the standard value as a drill repairing area;
s3, drilling compensation, namely manufacturing a drilling compensation belt, and performing drilling compensation in the drilling compensation area selected in the step S2, wherein the drilling depth of the drilling compensation belt is larger than that of the back drilling belt, so as to form a new back drilling hole;
s4, plating tin, namely plating a tin plating layer in the original back drilled hole and the new back drilled hole through an electroplating process;
s5, etching, namely, etching the PCB;
and S6, stripping tin, wherein after the etching process in the step S5 is finished, the tin stripping treatment is carried out to expose the residual copper piles in the two back drilled holes.
And manufacturing the back drilling belt according to the processing standard of the finished PCB, and operating according to the existing PCB back drilling process to obtain the PCB with the original back drilling hole. At the moment, because the PCB has errors in the pressing process in the preorder process, the thickness of the PCB is not uniform, and if the back drill is arranged in a region with smaller board thickness of the PCB, the problems that the depth of the original back drill hole is too large and the length of the residual copper pile in the original back drill hole is too short can be caused. And measuring the plate thicknesses of a plurality of areas of the PCB with poor back drilling, and selecting an area with the plate thickness reaching a standard value to position a drill repairing area. And when the drill belt is manufactured, the drilling depth of the drill bit is larger than that of the initial back drill, and a new back drill hole is formed after the drill bit is repaired. The purpose of the tin plating layer is to protect the residual copper pile which is too short in the original back drilling hole, so that the risk that the PCB is opened due to the fact that the residual copper pile continues to be corroded in the etching process is avoided from increasing, but the tin plating layer is electroplated in the new back drilling hole, so that the increased drilling depth is used for offsetting the error that the residual copper pile in the new back drilling hole after the tin plating layer cannot be etched. And executing an etching process according to the plate making process flow of the PCB. And after the etching process is finished, removing the tin plating layer electroplated on the surface of the residual copper pile by a tin removing process. And obtaining the PCB with the length of the residual copper pile meeting the requirement. The problem of open circuit of the PCB caused by over short residual copper piles is avoided.
Example 2:
on the basis of the embodiment 1, the technical scheme is carried out, and the specific improvement scheme is as follows:
in one embodiment, the rotational speed of the redrill drill strip is the same as the rotational speed of the backdrill drill strip in order to conform the new backdrill hole to the machining standard.
In one embodiment, to improve the production efficiency in batch processing, the drilling depth difference is estimated during drill-back, and the drilling depth of the drill-back tape is 50 μm greater than that of the drill-back tape.
In one embodiment, the cutter model of the drill repairing belt is selected according to the measured thickness of the drill repairing area of the PCB.
Example 3:
on the basis of the embodiment 1 or the embodiment 2, the technical scheme is improved as follows:
in one embodiment, to enhance the bonding force between the copper layer and the tin layer, a micro-etching process is performed to form a rough surface on the copper surface before the tin plating process is performed, so as to enhance the adhesion.
In one embodiment, the PCB is patterned by exposure method, and the process flow comprises: cutting, coating, drying, exposing, developing, drying, etching and demolding.
In one embodiment, the PCB is patterned by a silk-screen printing method, and the process flow is as follows: cutting, screen printing, etching and demolding.
From the two PCB circuit board drawing methods, the PCB circuit board comprises an etching step in the drawing process, and the two PCB circuit board drawing methods can generate an erosion effect on the residual copper pile in the original back drilling hole, so that the scheme is suitable for the two PCB circuit board drawing methods.
In one embodiment, the solder stripping process is to soak the PCB in a leaching agent and heat the PCB to 60 ℃.
In one embodiment, the leaching agent is a nitric acid-sodium sulfamate-pyrrolidone-ferric trichloride solution.
In one embodiment, the tin plating layer has a thickness of 4-6 μm.
The tin stripping process adopts nitric acid-sodium sulfamate-pyrrolidone-ferric trichloride solution as a leaching agent, can dissolve a tin plating layer in the leaching agent through chemical reaction, and can reduce the tin plating layer into tin crystals for recycling through an oxidant, so that the cost can be greatly saved.
By optimizing the details of each process, the effects of improving the production efficiency, saving the cost and expanding the application range are achieved.
The technology of the invention is applied to a large data server system board set based on a purley platform.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any other embodiments that can be easily conceived or replaced by those skilled in the art within the technical scope of the present invention should be covered by the present invention.
The present invention is not limited to the above-described embodiments, and various modifications and variations of the present invention are intended to be included within the scope of the claims and the equivalent technology of the present invention if they do not depart from the spirit and scope of the present invention.
Claims (10)
1. A method for processing a PCB back drilling defective board is characterized by comprising the following steps: s1, back drilling, namely manufacturing a back drilling belt, and performing back drilling processing on the PCB to form a back drilling hole;
s2, measuring, namely measuring the thickness of the PCB circuit board in the area where the back drilling hole is located, screening out a board with the thickness smaller than a standard value as a defective board, measuring the thicknesses of other areas of the defective board, and selecting the area with the board thickness meeting the standard value as a drill repairing area;
s3, drilling compensation, namely manufacturing a drilling compensation belt, and performing drilling compensation in the drilling compensation area selected in the step S2, wherein the drilling depth of the drilling compensation belt is larger than that of the back drilling belt, so as to form a new back drilling hole;
s4, plating tin, namely plating a tin plating layer in the original back drilled hole and the new back drilled hole through an electroplating process;
s5, etching, namely, etching the PCB;
and S6, stripping tin, wherein after the etching process in the step S5 is finished, the tin stripping treatment is carried out to expose the residual copper piles in the two back drilled holes.
2. The method for processing the bad board of the PCB back drilling of claim 1, wherein in the step S3, the rotation speed of the drill back drilling belt is the same as the rotation speed of the drill back drilling belt.
3. The method for processing a poor board for back drilling of PCB according to claim 1, wherein in the step of S3, the drilling depth of the drill strip for additional drilling is 50 μm more than the drilling depth of the drill strip for back drilling.
4. The method for processing PCB back drilling defective board as claimed in claim 1, wherein in the step S3, the cutter type of the drill repairing tape is selected according to the thickness of the drill repairing area of PCB circuit board measured in the step S2.
5. The method for processing the bad PCB of the PCB claim 1, wherein before the step S4 tin plating process is performed, a micro-rough surface is formed on the copper surface by a micro-etching process to enhance the adhesion.
6. The method for processing the PCB poor back drilling board according to claim 1, wherein the PCB circuit board in the step S5 is patterned by an exposure method, and the process flow comprises the following steps: cutting, coating, drying, exposing, developing, drying, etching and demolding.
7. The method for processing the PCB poor back drilling board according to claim 1, wherein the PCB circuit board in the step S5 is drawn by a silk screen printing method, and the process flow is as follows: cutting, screen printing, etching and demolding.
8. The method as claimed in claim 1, wherein the solder stripping process in the step S6 comprises soaking the PCB in a leaching agent and heating to 60 ℃.
9. The method for treating the PCB back drilling defective board as recited in claim 8, wherein the leaching agent is nitric acid-sodium sulfamate-pyrrolidone-ferric trichloride solution.
10. The method for processing a PCB back drilling defective board according to claim 1, wherein in the step S4, the thickness of the tin plating layer is 4-6 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911417957.5A CN111065207B (en) | 2019-12-31 | 2019-12-31 | Method for processing poor back-drilled board of PCB |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911417957.5A CN111065207B (en) | 2019-12-31 | 2019-12-31 | Method for processing poor back-drilled board of PCB |
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| CN111065207A CN111065207A (en) | 2020-04-24 |
| CN111065207B true CN111065207B (en) | 2021-10-08 |
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| CN113179587A (en) * | 2021-04-09 | 2021-07-27 | 广州广合科技股份有限公司 | Circuit board and back drilling process thereof |
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| CN102958289A (en) * | 2011-08-24 | 2013-03-06 | 深南电路有限公司 | Printed circuit board processing technology |
| CN105025658A (en) * | 2015-06-30 | 2015-11-04 | 开平依利安达电子第五有限公司 | Mechanical backdrilling method for PCB |
| CN105208777A (en) * | 2015-09-10 | 2015-12-30 | 深圳崇达多层线路板有限公司 | Manufacturing method for circuit board with metallization back drilled hole |
| CN108366489A (en) * | 2018-01-22 | 2018-08-03 | 深圳崇达多层线路板有限公司 | A kind of undesirable method of optimization back drill aperture turmeric |
| CN108879998A (en) * | 2018-08-07 | 2018-11-23 | 吉林大学 | A kind of high efficiency motor automobile wireless charging unit |
| KR20190065540A (en) * | 2017-12-03 | 2019-06-12 | 유니마이크로텍 (주) | Back-drilling apparatus and back-drilling method |
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2019
- 2019-12-31 CN CN201911417957.5A patent/CN111065207B/en active Active
Patent Citations (6)
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| CN102958289A (en) * | 2011-08-24 | 2013-03-06 | 深南电路有限公司 | Printed circuit board processing technology |
| CN105025658A (en) * | 2015-06-30 | 2015-11-04 | 开平依利安达电子第五有限公司 | Mechanical backdrilling method for PCB |
| CN105208777A (en) * | 2015-09-10 | 2015-12-30 | 深圳崇达多层线路板有限公司 | Manufacturing method for circuit board with metallization back drilled hole |
| KR20190065540A (en) * | 2017-12-03 | 2019-06-12 | 유니마이크로텍 (주) | Back-drilling apparatus and back-drilling method |
| CN108366489A (en) * | 2018-01-22 | 2018-08-03 | 深圳崇达多层线路板有限公司 | A kind of undesirable method of optimization back drill aperture turmeric |
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Address after: 510730 No. 22, Ying Ying Road, Guangzhou Free Trade Zone, Guangzhou, Guangdong Applicant after: Guangzhou Guanghe Technology Co., Ltd Address before: 510730 No. 22, Ying Ying Road, Guangzhou Free Trade Zone, Guangzhou, Guangdong Applicant before: DELTON TECHNOLOGY (GUANGZHOU) Inc. |
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