CN113179587A - Circuit board and back drilling process thereof - Google Patents
Circuit board and back drilling process thereof Download PDFInfo
- Publication number
- CN113179587A CN113179587A CN202110384311.2A CN202110384311A CN113179587A CN 113179587 A CN113179587 A CN 113179587A CN 202110384311 A CN202110384311 A CN 202110384311A CN 113179587 A CN113179587 A CN 113179587A
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- CN
- China
- Prior art keywords
- hole
- pcb
- circuit board
- copper layer
- drilling
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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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
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/11—Printed elements for providing electric connections to or between printed circuits
- H05K1/115—Via connections; Lands around holes or via connections
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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
- H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
- H05K3/42—Plated through-holes or plated via connections
- H05K3/425—Plated through-holes or plated via connections characterised by the sequence of steps for plating the through-holes or via connections in relation to the conductive pattern
- H05K3/427—Plated through-holes or plated via connections characterised by the sequence of steps for plating the through-holes or via connections in relation to the conductive pattern initial plating of through-holes in metal-clad substrates
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- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Printing Elements For Providing Electric Connections Between Printed Circuits (AREA)
Abstract
The invention relates to the technical field of circuit board manufacturing, in particular to a circuit board and a back drilling process thereof, wherein the back drilling process of the circuit board comprises the following steps of S1: drilling a PCB to obtain a through hole; s2: electroplating the through hole prepared in the step S1 to plate a copper layer on the through hole; s3: performing first tin plating on the copper layer prepared in the step S2 to plate a first tin layer on the surface of the copper layer; s4: manufacturing a transmission line on the PCB processed in the step S3, and enabling the transmission line to be connected with the copper layer on the through hole; s5: back drilling the through hole on the PCB processed in the step S4 to obtain a back drilling hole; s6: and performing secondary tin plating on the copper layer on the back-drilled through hole of S5 to plate a second tin layer on the surface of the copper layer and/or the surface of the residual copper to obtain the back-drilled through hole. The circuit board manufactured by the method has the advantages of simple structure and easiness in preparation.
Description
Technical Field
The invention relates to the technical field of circuit board manufacturing, in particular to a circuit board and a back drilling process thereof.
Background
Because in the PCB board manufacturing process, need carry out the pressfitting to the PCB board for the thick board of PCB board for a bit can be thick littleer than the standard board, promptly, PCB can have the thick condition of board weak point, and the thickness after this kind of PCB board attenuation is inconvenient to be detected out or can't be detected, just so increases the preparation difficulty of PCB board: when the thickness of the PCB is too thin, the back drilling still carries out back drilling according to the standard thickness of the PCB because the thickness of the PCB cannot be detected, at the moment, as shown in figure 1, the back drilling hole 6 can drill more deep to drill more residual copper 8, and the subsequent normal etching can etch the exposed residual copper 8 as shown in figure 2, so that the transmission line 5 is disconnected from the residual copper 8, and the transmission line 5 has the risk of open circuit. However, this problem is not found at present, and no effective solution is proposed for this problem, and at present, the problem board is only scrapped or not found in time, which leads to complaints from customers.
Disclosure of Invention
One of the purposes of the invention is to provide a back drilling process of a circuit board to avoid the defects in the prior art, and the method can effectively prevent the problem that the transmission line is disconnected with residual copper when the circuit board is etched.
One of the purposes of the invention is realized by the following technical scheme:
provides a back drilling process of a circuit board, which comprises the following steps,
s1: drilling a PCB to obtain a through hole;
s2: electroplating the through hole prepared in the step S1 to plate a copper layer on the through hole;
s3: performing first tin plating on the copper layer prepared in the step S2 to plate a first tin layer on the surface of the copper layer;
s4: manufacturing a transmission line on the PCB processed in the step S3, and enabling the transmission line to be connected with the copper layer on the through hole;
s5: back drilling the through hole on the PCB processed in the step S4 to obtain a back drilling hole;
s6: and performing secondary tin plating on the copper layer on the back-drilled through hole of S5, and plating a second tin layer on the surface of the copper layer and/or the surface of the residual copper to obtain the back-drilled through hole.
Further, in S5, before back drilling, the method further includes separating the drill strip according to a standard thickness of the PCB.
Further, in the step S5, a drilling depth of 30-70 microns is added to the thick area of the PCB.
Further, in S5, a drilling depth of 50 μm is performed for the thick region of the PCB.
Further, in the S6, the thickness of the second tin layer is 3 to 9 microns.
Further, in S6, the second tin layer has a thickness of 4 μm.
Further, after the step S6, the method further includes performing etching treatment and tin stripping treatment on the PCB in sequence.
The back drilling process of the circuit board has the beneficial effects that:
(1) according to the invention, the first tin plating is carried out before back drilling to protect the copper layer, and the second tin plating is carried out after back drilling to coat the residual copper broken by the back drilling hole, so that the problem of disconnection between the transmission line and the residual copper during etching is avoided.
(2) According to the invention, because the second tinning is added after the back drilling, the drilling tape does not need to be strictly separated according to the thickness of the PCB, and the workload of the back drilling is effectively reduced.
(3) According to the invention, only the second tinning is needed, so that the problem that the poor PCB with a smaller thickness is scrapped after back drilling can be solved, and the production benefit of the PCB is effectively improved.
The second purpose of the invention is to provide a circuit board which avoids the defects in the prior art and has the advantages of simple structure and easy preparation.
The second purpose of the invention is realized by the following technical scheme:
a circuit board is provided, which comprises a circuit board manufactured by adopting the back drilling process of the circuit board.
Drawings
The invention is further illustrated by means of the attached drawings, but the embodiments in the drawings do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived on the basis of the following drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a poor PCB board after backdrilling.
FIG. 2 is a schematic diagram of a structure of a poor PCB after back drilling and etching of residual copper.
Fig. 3 is a schematic structural view of a poor PCB board of the present invention after back drilling and a second tin plating.
Reference numerals
A PCB board 1; a through hole 2; a copper layer 3; a first tin layer 4; a transmission line 5; back drilling 6; a second tin layer 7; residual copper 8.
Detailed Description
The invention is further described with reference to the following examples.
Example 1
In order to explain the excellent effects of the present invention, the present embodiment uses a defective PCB (having a small thickness) as a processing object, and in practical applications, the process of the present invention can be applied to a PCB having a normal thickness.
The back drilling process of the circuit board disclosed in this embodiment, wherein the structure related to the bad PCB is shown in fig. 3, includes the following steps,
s1: drilling a PCB (printed Circuit Board) 1 to obtain a through hole 2;
s2: electroplating the through hole 2 prepared in the step S1 to enable the through hole 2 to be plated with a copper layer 3, wherein the copper layer 3 is used as a signal flowing layer;
s3: performing first tin plating on the copper layer 3 prepared in the step S2, so that the surface of the copper layer 3 is plated with a first tin layer 4, wherein the first tin layer 4 is used for protecting the copper layer 3;
s4: manufacturing a transmission line 5 on the PCB 1 processed in the step S3, and enabling the transmission line 5 to be connected with the copper layer 3 on the through hole 2, wherein the transmission line 5 is used for realizing signal transmission;
s5: separating a drilling strip according to the standard plate thickness of the PCB 1, and back-drilling the through hole 2 on the PCB 1 processed in the step S4 to obtain a back-drilled hole 6; wherein, the thick area of the PCB board 1 is drilled with a depth of 30-70 microns, preferably 50 microns. Unnecessary residual copper 8 can be effectively removed for the drilling depth of the area with larger plate thickness.
S6: and (3) carrying out secondary tin plating on the copper layer 3 on the back-drilled through hole 2 in the S5 mode, and plating a second tin layer 7 on the surface of the copper layer 3 and the surface of the residual copper 8 to obtain the back-drilled through hole 2. As shown in fig. 3, the second tin layer 7 covers not only the copper layer 3 and the residual copper 8 but also the inner wall of the back-drilled hole 6, thus allowing easy tin plating. The thickness of the second tin layer 7 is 3-9 microns, preferably 4 microns, and the second tin layer 7 with the thickness of 4 microns can not only protect the copper layer 3, but also save tin.
And after the step S6, the steps of sequentially carrying out etching treatment and tin stripping treatment on the PCB 1 are also included.
Example 2
This example is different from example 1 in that a CB plate having a normal thickness P is treated and after the second tin plating, the surface of the copper layer is plated with a second tin layer. In this case, since the residual copper is not drilled out, it is not necessary to coat the residual copper. In actual production, no matter the thickness of the PCB is normal or not, the tin plating is carried out for the second time, so that a drilling belt does not need to be strictly separated according to the thickness of the PCB during back drilling, and the workload of the back drilling is effectively reduced. The other processes of this embodiment are the same as those of embodiment 1, and are not described herein again.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the protection scope of the present invention, although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (8)
1. The back drilling process of the circuit board is characterized by comprising the following steps: comprises the following steps of (a) carrying out,
s1: drilling a PCB to obtain a through hole;
s2: electroplating the through hole prepared in the step S1 to plate a copper layer on the through hole;
s3: performing first tin plating on the copper layer prepared in the step S2 to plate a first tin layer on the surface of the copper layer;
s4: manufacturing a transmission line on the PCB processed in the step S3, and enabling the transmission line to be connected with the copper layer on the through hole;
s5: back drilling the through hole on the PCB processed in the step S4 to obtain a back drilling hole;
s6: and performing secondary tin plating on the copper layer on the back-drilled through hole of S5, and plating a second tin layer on the surface of the copper layer and/or the surface of the residual copper to obtain the back-drilled through hole.
2. The backdrilling process of a wiring board according to claim 1, characterized in that: in the step S5, before back drilling, the method further includes separating the drill strip according to the standard thickness of the PCB.
3. The backdrilling process of a wiring board according to claim 2, characterized in that: and in the step S5, drilling the thick area of the PCB to a depth of 30-70 microns.
4. The backdrilling process of a wiring board according to claim 3, wherein: in S5, a drilling depth of 50 μm is performed for the thick region of the PCB.
5. The backdrilling process of a wiring board according to claim 1, characterized in that: in the S6, the thickness of the second tin layer is 3-9 microns.
6. The backdrilling process of a wiring board according to claim 5, wherein: in S6, the second tin layer has a thickness of 4 μm.
7. The backdrilling process of a wiring board according to claim 1, characterized in that: and after the step S6, the method further comprises the step of carrying out etching treatment and tin stripping treatment on the PCB in sequence.
8. A circuit board, characterized by: the circuit board comprises the circuit board prepared by adopting the back drilling process of the circuit board as claimed in any one of claims 1 to 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110384311.2A CN113179587A (en) | 2021-04-09 | 2021-04-09 | Circuit board and back drilling process thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110384311.2A CN113179587A (en) | 2021-04-09 | 2021-04-09 | Circuit board and back drilling process thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113179587A true CN113179587A (en) | 2021-07-27 |
Family
ID=76924945
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110384311.2A Pending CN113179587A (en) | 2021-04-09 | 2021-04-09 | Circuit board and back drilling process thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113179587A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20110048094A (en) * | 2009-11-02 | 2011-05-11 | 정민식 | Back-up board for drilling printed circuit board |
| CN111065207A (en) * | 2019-12-31 | 2020-04-24 | 广合科技（广州）有限公司 | Method for processing poor back-drilled board of PCB |
| CN111107715A (en) * | 2020-01-15 | 2020-05-05 | 江门崇达电路技术有限公司 | Manufacturing method of HDI plate back drilling hole |
-
2021
- 2021-04-09 CN CN202110384311.2A patent/CN113179587A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20110048094A (en) * | 2009-11-02 | 2011-05-11 | 정민식 | Back-up board for drilling printed circuit board |
| CN111065207A (en) * | 2019-12-31 | 2020-04-24 | 广合科技（广州）有限公司 | Method for processing poor back-drilled board of PCB |
| CN111107715A (en) * | 2020-01-15 | 2020-05-05 | 江门崇达电路技术有限公司 | Manufacturing method of HDI plate back drilling hole |
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| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210727 |
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| RJ01 | Rejection of invention patent application after publication |