Manufacturing method of 5G motherboard circuit board

Abstract

This application is a divisional application of application number 202110464268.0. The manufacturing method of the 5G motherboard circuit board of the present invention comprises the following steps: S1: cutting; S2: inner layer circuit; S3: first inspection; S4: pressing plate; S5: drilling; S6: copper plating and board surface electroplating; S7: pattern electroplating; S9: resin plugging; S10: resin grinding; S11: automatic optical inspection; S12: copper plating and VCP electroplating; S13: outer layer circuit pattern transfer; S14: pattern electroplating, plating a layer of tin on the circuit pattern as an anti-etching protective layer for the circuit; S15: outer layer etching to form the outer layer circuit pattern; S16: second inspection, i.e., passing through a reflow oven; S17: WF+QR code / character printing, printing a uniform layer of photosensitive solder mask ink on the circuit board; S18: measuring impedance and low loss; S19: post-processing. The present invention provides a method for manufacturing a 5G motherboard circuit board. By eliminating the tin plating process and the etching process in step S7, the two processes are optimized to solve the problem of complicated existing production technology processes.

Description

[0001] This application is a divisional application. The application number of the original application is 202110464268.0, the application date is April 28, 2021, and the name of the invention is "Production method of 5G motherboard circuit board".

Technical field

[0002] The present invention relates to the field of circuit boards, and in particular to a method for manufacturing a 5G mainboard circuit board. [Background Technology]

[0003] With the rapid development of communications technology and the commercial rollout of 5G, the design and manufacturing of electronic circuit boards (PCBs), a core material in the 5G industry chain, is inevitably trending towards high-frequency and high-speed fabrication. The application of high-frequency, high-speed PCBs in 5G communications will further deepen. While 5G presents opportunities for the PCB industry, it also places higher and more stringent technical requirements. Its performance in signal transmission speed, integration, heat dissipation, and multi-layer fabrication significantly surpasses that of 4G. The current 5G PCB manufacturing process includes: cutting, inner layer primary inspection, lamination, drilling and initial plating, copper plating / board plating, pattern plating (copper and tin plating), backdrilling, etching, backdrill testing, resin plugging, resin grinding, automated optical inspection (AOI), copper plating / VCP, outer layer traces, pattern plating (tin plating), outer layer etching, secondary inspection (IR furnace), WF (Wave Forming) with QR code scanning, impedance and low-loss testing, high-voltage testing, gold plating, character marking, plating, ET, FQC, and PK. The existing 5G circuit board PCB manufacturing technology still has the defect of cumbersome production process, which makes it difficult to improve production efficiency and reduce production costs. [Summary of the invention]

[0004] The present invention solves the technical problem of complicated production process in the existing 5G circuit board PCB manufacturing method, and provides a manufacturing method of a 5G mainboard circuit board with simple structure and reasonable design.

[0005] The present invention is achieved through the following technical solutions:

[0006] The manufacturing method of the 5G motherboard circuit board includes the following steps:

[0007] S1: Cutting the copper clad laminate to form the inner copper clad laminate;

[0008] S2: Inner layer circuit, a layer of photosensitive material is attached to the copper foil of the inner copper clad board, and the inner layer circuit pattern is formed after etching and development;

[0009] S3: First inspection, performing quality inspection on the inner copper clad laminate after step S2;

[0010] S4: Lamination, arranging the inner copper clad laminate and the resin film that have passed the quality inspection in a preset arrangement, and then laminating them to form a laminated circuit board;

[0011] S5: Drilling, drilling through holes in the laminated circuit board;

[0012] S6: Copper deposition and board surface electroplating, wherein copper deposition is to deposit a layer of copper layer in the through hole to connect the layers of the laminated circuit board by copper deposition, so that the through hole forms a conductive hole; board surface electroplating is to electroplate the laminated circuit board by full board electroplating to form a conductive copper layer on the conductive hole and board surface of the laminated circuit board;

[0013] S7: Graphic electroplating to make the conductive copper layer reach a preset thickness;

[0014] S8: Back drilling, using mechanical drilling to make the via hole reach the preset depth;

[0015] S9: Resin plugging, using vacuum resin plugging, the vias are divided into resin plugged holes and non-resin plugged holes;

[0016] S10: grinding resin, grinding away excess resin after the resin plugging hole;

[0017] S11: Automatic optical inspection to check the fullness of the plug hole;

[0018] S12: Copper deposition and VCP electroplating, the holes after resin plugging are electroplated and filled, and the copper thickness of the holes and the board surface of the non-resin plugged holes is made to reach the preset finished copper layer thickness through VCP electroplating;

[0019] S13: Transferring the outer layer circuit pattern; a layer of dry film photosensitive material is applied to the copper foil surface of the laminated circuit board, and then the laser direct imaging technology is used for registration exposure, and the circuit pattern is formed after development;

[0020] S14: Pattern electroplating: a layer of tin is plated on the circuit pattern as an anti-etching protective layer for the circuit;

[0021] S15: etching the outer layer to form an outer layer circuit pattern;

[0022] S16: Second inspection, i.e. reflow oven;

[0023] S17: WF+QR code / character printing, printing a uniform layer of photosensitive solder mask ink on the circuit board;

[0024] S18: Measure impedance and Lowloss, measure the impedance module and LowLoss in the production board;

[0025] S19: post-processing;

[0026] Wherein, in step S4, plastic rivets are used for pressing;

[0027] In step S5, the through hole is drilled in one go, during which a phenolic backing plate is used for production, and a melamine backing plate is used as a cover plate, and the cover plate is first drilled with the pipe position hole;

[0028] In step S8, the following steps are also included:

[0029] S801: Use mechanical drilling to make the via hole reach a preset depth;

[0030] S802: Drilling out the through-hole segments that have no connection or transmission function;

[0031] S803: High pressure water washing after back drilling;

[0032] S804: Fully inspect the leak-proof drilling of aluminum cover plates using a hole counting machine.

[0033] In step S10 , the excess resin includes the resin on the hole mouth after plugging and the resin on the board surface.

[0034] The method for manufacturing the 5G motherboard circuit board as described above, in step S15, further includes the following steps:

[0035] S1501: film removal;

[0036] S1502: etching;

[0037] S1503: One-time tin stripping;

[0038] S1504: faded film;

[0039] S1505: Etch the copper underneath the dry film that is not protected by tin;

[0040] S1506: Secondary tin stripping until the circuit underneath the tin is exposed, thus forming the outer circuit pattern.

[0041] The method for manufacturing the 5G motherboard circuit board as described above, in step S16, further includes the following steps:

[0042] S1601: Inspect the outer circuit using optical inspection equipment;

[0043] S1602: The circuit board that has passed the inspection will be put into the reflow oven.

[0044] The method for manufacturing the 5G motherboard circuit board as described above, in step S19, further includes the following steps:

[0045] S1901: Immersion Gold;

[0046] S1902: gong board;

[0047] S1903: ET;

[0048] S1904: FQC;

[0049] S1905: FQC.

[0050] The method for manufacturing the 5G motherboard circuit board as described above, in step S9, further includes the following steps:

[0051] S901: Add a grinding plate before the resin plug hole;

[0052] S902: Roughen the copper surface.

[0053] Compared with the prior art, the present invention has the following advantages:

[0054] The present invention provides a method for manufacturing a 5G motherboard circuit board. By eliminating the tin plating and etching processes in step S7, the two processes are optimized, solving the problem of cumbersome existing production processes. This achieves the purpose of increasing production efficiency and reducing production costs.

Brief Description of the Drawings

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0056] Figure 1 It is a process flow chart of the present invention. [Specific implementation method]

[0057] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0058] When ordinal numbers such as "first" and "second" are mentioned in the embodiments of the present invention, unless they actually express the meaning of order according to the context, they should be understood as being merely for the purpose of distinction.

[0059] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0060] The manufacturing method of the 5G motherboard circuit board includes the following steps:

[0061] S1: Cutting, cutting the copper clad laminate to form an inner copper clad laminate; in this embodiment, a high-frequency and high-speed copper clad laminate is used, and after cutting, its surface is cleaned and dried.

[0062] S2: Inner layer circuit: a layer of photosensitive material is attached to the copper foil on the inner copper clad board surface, and the inner layer circuit pattern is formed after etching and development; in this step, the method of positioning exposure with black film is used, and the inner layer circuit pattern is formed after etching and development.

[0063] S3: First inspection, performing quality inspection on the inner copper clad laminate after step S2;

[0064] S4: Lamination, arranging the inner copper clad laminate and the resin film that have passed the quality inspection in a preset arrangement, and then laminating them to form a laminated circuit board;

[0065] S5: Drilling, drilling through holes in the laminated circuit board;

[0066] S6: Copper deposition and board surface electroplating, wherein copper deposition is to deposit a layer of copper layer in the through hole to connect the layers of the laminated circuit board by copper deposition, so that the through hole forms a conductive hole; board surface electroplating is to electroplate the laminated circuit board by full board electroplating to form a conductive copper layer on the conductive hole and board surface of the laminated circuit board;

[0067] S7: Graphic electroplating makes the conductive copper layer reach the preset thickness; copper plating is to thicken the copper layer in the hole and circuit to improve the plating quality.

[0068] S8: Back drilling, using mechanical drilling to make the via hole reach the preset depth;

[0069] S9: Resin plugging, using vacuum resin plugging, the vias are divided into resin plugged holes and non-resin plugged holes;

[0070] S10: grinding resin, grinding away excess resin after the resin plugging hole;

[0071] S11: Automatic optical inspection to check the fullness of the plug hole. In this embodiment, a dedicated automatic optical inspection machine for resin plug holes is used to check the fullness of the plug hole 100%;

[0072] S12: Copper deposition and VCP electroplating, the holes after resin plugging are electroplated and filled, and the copper thickness of the holes and the board surface of the non-resin plugged holes is made to reach the preset finished copper layer thickness through VCP electroplating;

[0073] S13: Transferring the outer layer circuit pattern; a layer of dry film photosensitive material is applied to the copper foil surface of the laminated circuit board, and then the laser direct imaging technology is used for registration exposure, and the circuit pattern is formed after development;

[0074] S14: Pattern electroplating: a layer of tin is plated on the circuit pattern as an anti-etching protective layer for the circuit;

[0075] S15: etching the outer layer to form an outer layer circuit pattern;

[0076] S16: Second inspection, i.e. passing through the reflow oven; optical inspection equipment is used to check for quality defects such as open and short circuits in the outer layer and poor appearance. After the inspection, it is passed through the reflow oven, which can reduce thermal stress and improve the dimensional stability of the high-frequency and high-speed 5G motherboard circuit board.

[0077] S17: WF+QR code / character printing: A uniform layer of photosensitive solder mask ink is printed on the circuit board. The 5G motherboard circuit board character production method is changed from silk screen printing to inkjet printing, and the QR code traceability information is printed simultaneously. The silk screen character production requires the PCB solder mask to cure before the PCB solder mask is screen printed on the screen, and finally the characters are baked again at high temperature. The inkjet printing method prints the characters on the PCB before the solder mask is cured at high temperature. After the characters are printed, they are cured at high temperature along with the solder mask. Compared with silk screen printing, the inkjet printing method reduces the high-temperature process and eliminates the need for stencil tools, greatly improving production efficiency. A uniform layer of photosensitive solder mask ink is printed on the circuit board to achieve the purpose of solder resistance and insulation. The QR code traceability information and marking characters are inkjet printed before the solder mask ink is cured at high temperature.

[0078] S18: Measure impedance and Lowloss, measure the impedance module and LowLoss in the production board;

[0079] S19: Post-processing.

[0080] The present invention provides a method for manufacturing a 5G motherboard circuit board. By eliminating the tin plating process and the etching process in step S7, the two processes are optimized, and the problem of the cumbersome process of the existing production technology is solved. The purpose of improving production efficiency and reducing production costs is achieved. Back drilling after pattern electroplating reduces the etching process, which can effectively solve the bite caused by etching - improving the back drilling Stub value. The original process design is to perform outer layer circuit, pattern electroplating, back drilling and etching. According to this process, the back drill stub is 2.67mil. When etching, the exposed copper on the back drill surface is not protected by tin during etching. After etching, the stub is 0mil after being bitten, resulting in failure of the 5G signal test. By adjusting the process and eliminating the etching process after back drilling, the bite caused by etching can be effectively solved, and the problem of poor stub can be solved.

[0081] Furthermore, as a preferred embodiment of this solution but not a limitation, in step S4, plastic rivets are used for lamination. The design of the secondary outer layer of the mainboard high-level circuit board requires 3 P sheets. The three PP sheets cannot use DIS fusion blocks. It is necessary to start from the inner layer dry film alignment and use fusion + 10 head rivets for production; the lamination process uses plastic rivets to solve the problem of inner layer short circuit caused by rivet chips generated in the traditional metal rivet riveting process. The rivet length is adjusted with the flower side facing up to solve the problem of copper foil wrinkling at the nailing position.

[0082] Furthermore, as a preferred embodiment of this solution, but not limiting, in step S5, the through holes are drilled in one go, using a phenolic backing plate for production and a melamine backing plate as the cover plate, with the pipe holes drilled in the cover plate first. During drilling, the melamine backing plate is used as both the base plate and the cover plate, and holes larger than 1.4 mm are produced with the cover plate. The cover plate is drilled with the pipe holes, effectively solving the problem of flashing during drilling of 5G high-frequency, high-speed plates.

[0083] Furthermore, as a preferred embodiment of this solution but not limiting, step S8 further includes the following steps:

[0084] S801: Use mechanical drilling to make the via hole reach a preset depth;

[0085] S802: Drilling out the through-hole segments that have no connection or transmission function;

[0086] S803: High pressure water washing after back drilling;

[0087] S804: Fully inspect the leak-proof drilling of aluminum cover plates using a hole counting machine.

[0088] Utilize the depth control function of the mechanical drill rig to drill holes with certain depth requirements on the conductive holes with a larger diameter drill bit, and drill out the through-hole sections that do not play any connection or transmission role to avoid reflection, scattering, delay, etc. of 5G signal transmission, which will cause "distortion" to the signal. Double-sided back drilling is performed, and all parts are high-pressure water washed after back drilling. The aluminum cover plate is fully inspected by a hole counting machine to prevent leakage.

[0089] Furthermore, as a preferred embodiment of the present solution but not a limitation, in step S10, the excess resin includes the resin protruding from the hole mouth after plugging the hole and the resin on the board surface.

[0090] Furthermore, as a preferred embodiment of this solution but not limiting, in step S15, the following steps are further included:

[0091] S1501: film removal;

[0092] S1502: etching;

[0093] S1503: One-time tin stripping;

[0094] S1504: faded film;

[0095] S1505: Etch the copper underneath the dry film that is not protected by tin;

[0096] S1506: Secondary tin stripping until the circuit underneath the tin is exposed, thus forming the outer circuit pattern.

[0097] Furthermore, as a preferred embodiment of this solution but not limiting, step S16 further includes the following steps:

[0098] S1601: Inspect the outer circuit using optical inspection equipment;

[0099] S1602: The circuit board that has passed the inspection will be put into the reflow oven.

[0100] Furthermore, as a preferred embodiment of this solution but not limiting, in step S19, the following steps are also included:

[0101] S1901: Immersion Gold;

[0102] S1902: gong board;

[0103] S1903: ET;

[0104] S1904: FQC;

[0105] S1905: PK.

[0106] Furthermore, as a preferred embodiment of this solution but not limiting, step S9 further includes the following steps:

[0107] S901: Add a grinding plate before the resin plug hole;

[0108] S902: Roughen the copper surface. This will enhance the bonding between the copper surface and the resin. The 5G motherboard design requires that "resin should not separate after 5 reflows." Therefore, to increase the roughness of the copper surface, the motherboard model adds step S9.

[0109] The working principle of this embodiment is as follows:

[0110] The present invention provides a method for manufacturing a 5G motherboard circuit board. By eliminating the tin plating and etching processes in step S7, the two processes are optimized, solving the problem of cumbersome existing production processes. This achieves the purpose of increasing production efficiency and reducing production costs.

[0111] The above are implementation methods provided in conjunction with specific content, and the specific implementation of this application is not limited to these descriptions. Any method structure that is similar to the method structure of this application, or any technical deduction or replacement based on the concept of this application, should be considered as the scope of protection of this application.

Claims

The manufacturing method of 1.5G motherboard circuit board is characterized in that: The following steps are involved: S1: Cutting the copper clad laminate to form the inner copper clad laminate; S2: Inner layer circuit, a layer of photosensitive material is attached to the copper foil of the inner copper clad board, and the inner layer circuit pattern is formed after etching and development; S3: First inspection, performing quality inspection on the inner copper clad laminate after step S2; S4: Lamination, arranging the inner copper clad laminate and the resin film that have passed the quality inspection in a preset arrangement, and then laminating them to form a laminated circuit board; S5: Drilling, drilling through holes in the laminated circuit board; S6: Copper deposition and board surface electroplating, wherein copper deposition is to deposit a layer of copper layer in the through hole to connect the layers of the laminated circuit board by copper deposition, so that the through hole forms a conductive hole; board surface electroplating is to electroplate the laminated circuit board by full board electroplating to form a conductive copper layer on the conductive hole and board surface of the laminated circuit board; S7: Graphic electroplating to make the conductive copper layer reach a preset thickness; S8: Back drilling, using mechanical drilling to make the via hole reach the preset depth; S9: Resin plugging, using vacuum resin plugging, the vias are divided into resin plugged holes and non-resin plugged holes; S10: grinding resin, grinding away excess resin after the resin plugging hole; S11: Automatic optical inspection to check the fullness of the plug hole; S12: Copper deposition and VCP electroplating, the holes after resin plugging are electroplated and filled, and the copper thickness of the holes and the board surface of the non-resin plugged holes is made to reach the preset finished copper layer thickness through VCP electroplating; S13: Transferring the outer layer circuit pattern; a layer of dry film photosensitive material is applied to the copper foil surface of the laminated circuit board, and then the laser direct imaging technology is used for registration exposure, and the circuit pattern is formed after development; S14: Pattern electroplating: a layer of tin is plated on the circuit pattern as an anti-etching protective layer for the circuit; S15: etching the outer layer to form an outer layer circuit pattern; S16: Second inspection, i.e. reflow oven; S17: WF+QR code / character printing, printing a uniform layer of photosensitive solder mask ink on the circuit board; S18: Measure impedance and Lowloss, measure the impedance module and LowLoss in the production board; S19: post-processing; Wherein, in step S4, plastic rivets are used for pressing; In step S5, the through hole is drilled in one go, during which a phenolic backing plate is used for production, and a melamine backing plate is used as a cover plate, and the cover plate is first drilled with the pipe position hole; In step S8, the following steps are also included: S801: Use mechanical drilling to make the via hole reach a preset depth; S802: Drilling out the through-hole segments that have no connection or transmission function; S803: High pressure water washing after back drilling; S804: Fully inspect the leak-proof drilling of aluminum cover plates using a hole counting machine; In step S10 , the excess resin includes the resin on the hole mouth after plugging and the resin on the board surface.

2. The method for manufacturing a 5G motherboard circuit board according to claim 1, wherein: In step S15, the following steps are also included: S1501: film removal; S1502: etching; S1503: One-time tin stripping; S1504: faded film; S1505: Etch the copper underneath the dry film that is not protected by tin; S1506: Secondary tin stripping until the circuit underneath the tin is exposed, thus forming the outer circuit pattern.

3. The method for manufacturing a 5G motherboard circuit board according to claim 1, wherein: In step S16, the following steps are also included: S1601: Inspect the outer circuit using optical inspection equipment; S1602: The circuit board that has passed the inspection will be put into the reflow oven.

4. The method for manufacturing a 5G motherboard circuit board according to claim 1, wherein: In step S19, the following steps are also included: S1901: Immersion Gold; S1902: gong board; S1903: ET; S1904: FQC; S1905: FQC.

5. The method for manufacturing a 5G motherboard circuit board according to claim 1, wherein: In step S9, the following steps are also included: S901: Add a grinding plate before the resin plug hole; S902: Roughen the copper surface.

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