CN110972399B

CN110972399B - Production process of printed circuit board with groove in middle of IC bonding pad

Info

Publication number: CN110972399B
Application number: CN201911315188.8A
Authority: CN
Inventors: 张军; 黄江波
Original assignee: Huangshi Xinghe Circuit Co ltd
Current assignee: Huangshi Xinghe Circuit Co ltd
Priority date: 2019-12-19
Filing date: 2019-12-19
Publication date: 2021-01-26
Anticipated expiration: 2039-12-19
Also published as: CN110972399A

Abstract

A production process of a printed circuit board with a groove in the middle of an IC bonding pad relates to the technical field of circuit boards and comprises the following steps: routing a board; carrying out primary routing; routing and slotting aiming at an IC area of a circuit board; grinding a plate; first pattern transfer; transferring wet ink patterns according to the position of an IC bonding pad and the position of a slot of the circuit board; second pattern transfer; transferring dry film patterns aiming at other positions of the circuit board except for the position of the IC bonding pad and the position of the slot; wherein, the graph of the second graph transfer is connected with the graph of the first graph transfer; electroplating the pattern; alkaline etching; and etching the subsequent step. According to the method, after one-time board milling, a board grinding process of an abrasive belt is added, and the smoothness of IC pins is ensured; the method aims at the problems that wet ink is adopted for pattern transfer in an IC area, dry films are adopted for pattern transfer in other areas, and the bonding force of the wet ink and a board surface is superior to that of the dry films and the board surface, so that the short circuit phenomenon and IC edge repair corrosion caused by liquid medicine in the electroplating process can be avoided.

Description

Production process of printed circuit board with groove in middle of IC bonding pad

Technical Field

The application relates to the technical field of circuit boards, in particular to a production process of a printed circuit board with a groove in the middle of an IC bonding pad.

Background

In the printed circuit board manufacturing industry, the manufacturing method of the printed circuit board with the groove formed in the middle of the IC bonding pad comprises the following three methods:

firstly, carrying out routing and slotting once in the middle of an IC bonding pad after pattern electroplating, and then etching, wherein in the method, copper sheets are thick after copper plating, and the phenomenon that the edges of the IC bonding pad are bitten due to copper sheet rolling and copper sheet pulling exists during routing once;

secondly, carrying out plate milling and slotting once after the plate is electrified, and then carrying out pattern transfer, wherein in the method, after copper sheet rolling and pattern transfer exist in the plate milling process once, dry film at the edge of a slot is loosened to plate copper and tin at the edge of the slot when liquid medicine passes through a slotted hole of the slot in the pattern electroplating process, so that fine short circuit between IC pins is formed after etching;

thirdly, a punch is directly adopted to punch a groove in the middle of the IC bonding pad after characters are finished, and the method has the phenomena of edge burst of the groove and copper sheet rolling after the plate is punched.

In summary, the methods for manufacturing the printed circuit board with the groove formed in the middle of the IC pad in the prior art all have their own disadvantages, and thus, there is no circuit board production process that can avoid the above technical problems.

Disclosure of Invention

The manufacturing method of the printed circuit board with the groove in the middle of the IC bonding pad in the prior art generally has the defects that the edge of the IC bonding pad is easy to bite and corrode, short circuit is easy to occur between IC pins, the edge of the groove is broken after the IC bonding pad is punched, copper sheets are rolled up and the like.

In order to solve the above technical problem, an embodiment of the present application provides a printed circuit board production process for forming a groove in the middle of an IC pad, including:

step one, routing a board;

secondly, routing the board once; routing and slotting aiming at an IC area of a circuit board;

step three, grinding the plate;

step four, transferring the graph for the first time; transferring wet ink patterns according to the position of an IC bonding pad and the position of a slot of the circuit board;

fifthly, transferring the graph for the second time; transferring dry film patterns aiming at other positions of the circuit board except for the position of the IC bonding pad and the position of the slot; wherein, the graph of the second graph transfer is connected with the graph of the first graph transfer;

step six, electroplating the pattern;

step seven, alkaline etching;

step eight, etching the subsequent steps.

In the above technical solution, further, the routing step includes: cutting, drilling, depositing copper and electrifying a plate; the etching subsequent step comprises: detecting, welding resistance, character, forming, electrical testing, OSP, final inspection and packaging.

In the above technical solution, further, in the second step, a phenolic aldehyde cover plate is added when routing.

In the above technical solution, further, in the fourth step, a plate grinding and volcanic ash mode is adopted for the pre-treatment of the pattern transfer.

In the above technical solution, further, in the fourth step, the thickness of the ink is required to be 25 μm to 35 μm when the wet ink is printed, the energy is greater than or equal to 7 grids when the wet ink is exposed, the exposure precision is required to be controlled within 25 μm, and the developing speed is 3 m/min.

In the above technical solution, further, in the fifth step, a coarsening liquid medicine is used for the pre-treatment of pattern transfer.

In the above technical solution, further, in the fifth step, the energy during exposure is greater than or equal to 7 lattices, the exposure precision is controlled within 25 μm, and the developing speed is 3.5 m/min.

In the above technical solution, further, in the plate electrode, the thickness of the base copper is increased by 30% to 60%.

In the above technical solution, further, there is a partial overlap at a connection between the graph of the second graph transfer and the graph of the first graph transfer.

In the above technical solution, further, in the second step, the rotation speed of the main shaft for routing the board is increased by 20%, the advancing speed is decreased by 30% to 50%, and the feed speed is decreased by 20% to 40%.

Compared with the prior art, the technical scheme of the embodiment of the application has the following beneficial effects:

the application provides a grooved printed circuit board production technology in middle of the IC pad, once gong the board after, increased the abrasive band and ground the board process, remove the flash of gong groove once to guarantee the planarization of IC foot, solve and reach the phenomenon that IC pad edge is bitten into and loses. Setting two times of pattern transfer procedures, wherein the first time of pattern transfer adopts wet ink to carry out pattern transfer and only aims at an IC area; and the second pattern transfer is performed by using a dry film, and is performed on the region except the IC region. The combination of the wet ink and the board surface is far better than the combination force of the dry film and the board surface, so that the problems of short circuit phenomenon and IC edge repair corrosion at the edge of the slot hole caused by the fact that the dry film at the edge of the slot hole is loosened due to the fact that the liquid medicine penetrates through the slot hole back and forth in the electroplating process are solved.

Drawings

Fig. 1 is a schematic flow chart of a process for manufacturing a printed circuit board with a groove in the middle of an IC pad according to an embodiment of the present application.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

The production process aims at a product of the printed circuit board with a groove in the middle of an IC bonding pad, wherein IC pins are required to be smooth, the edge of the IC bonding pad is required to be tangent to the groove edge, and the edge of the IC is not subjected to compensation and etching; in addition, the phenomena of burrs, short circuits, edge explosion, deviation of slot positions and the like are caused.

In view of the above, embodiments of the present application provide a process for manufacturing a printed circuit board with a groove in the middle of an IC pad.

Referring to fig. 1, a process for manufacturing a printed circuit board with a groove in the middle of an IC pad according to an embodiment of the present application includes:

cutting → drilling → copper deposition → board → one-time routing → abrasive belt grinding → the first pattern transfer → the second pattern transfer → pattern plating → alkaline etching → middle check → resistance welding → character → shaping → electric test → final check → packaging.

And S101, cutting.

The large material is cut into the designed PNL size.

And S102, drilling.

A plurality of holes are drilled in the substrate.

And S103, depositing copper.

A layer of copper is attached to the surface of the hole.

And S104, electrically connecting the plate.

And increasing the thickness of the copper layer on the surface of the base material and the copper layer in the hole by electroplating. It should be noted that the thickness of the electric copper of the plate is increased from 6-8 μm to 10-12 μm, so that the subsequent abrasive belt grinding of the plate is facilitated, and the effective copper thickness is not influenced.

And S105, routing at one time.

The special aluminum substrate milling cutter is adopted for milling the groove once, and the parameters of milling the groove once are adjusted, so that the rotating speed of the main shaft is improved by 20%, the advancing speed is reduced by 30% -50%, and the feed speed is reduced by 20% -40%.

In addition, when once gong board, the bottom surface of circuit board product sets up the backing plate, and the upper surface adds the phenolic aldehyde apron, and milling cutter gongs the groove in the lump to circuit board and phenolic aldehyde apron, can reduce gong board book copper skin phenomenon to guarantee that IC edge is not mended and is bitten and corroded.

And S106, sanding the plate.

The abrasive belt grinding plate needs to remove the burrs of the routing groove at one time, namely the copper sheet is rolled up, so that the smoothness of the IC pins is ensured.

And S107, first pattern transfer.

The first pattern transfer is directed to the IC area of the circuit board, including the IC pad locations and the slot locations, and the pattern transfer is in the form of a wet ink pattern transfer.

The first pattern transfer comprises pattern transfer pretreatment, specifically a plate grinding and volcanic ash mode, and the binding force of wet ink and a plate surface is fully ensured.

The pattern transfer parameters were as follows: when wet ink is printed, the thickness of the ink is ensured to be 25-35 mu m; the energy is 7 grids during exposure; the exposure precision is controlled within 25 μm, and the development speed is 3 m/min. Thereby ensuring that the edge of the IC pad is not undercut after etching.

And S108, second pattern transfer.

And the second time of pattern transfer is carried out on the circuit board except the IC area, and the pattern transfer is in the form of dry film pattern transfer. The pattern transfer of the second time can not be carried out by adopting ink, because the wet ink pattern transfer does not have the hole sealing capability, copper-free holes can not be manufactured, and meanwhile, the electroplating liquid medicine is easily polluted due to excessive use.

It should be noted that the graphics of the second graphics transfer need to be connected with the graphics of the first graphics transfer. Further, there is a 3mil overlap at the connection of the pattern of the second pattern transfer and the pattern of the first pattern transfer, ensuring that the two patterns are connected.

In addition, the second pattern transfer also comprises a pattern transfer pretreatment, specifically, a coarsening liquid medicine is adopted for pretreatment, so that the wet ink is prevented from being damaged.

The pattern transfer parameters were as follows: the energy is 7 grids during exposure; the exposure precision is controlled to be 25 mu m so as to reduce pattern offset; the speed of the pattern transfer is controlled to be 3.5m/min during the pattern transfer development.

And S109, pattern electroplating.

Electroplating parameter adjustment is carried out according to the requirements of the copper of the customer hole and the copper of the surface, so that the copper thickness requirement of the customer is met.

And S110, alkaline etching.

The alkaline etching comprises three steps of film stripping, etching and tin stripping.

Wherein, in the film removing process, the film removing speed needs to be reduced by 50 percent, so as to achieve the degree of completely removing the dry film and the wet ink; in etching, normally adjusting etching parameters according to the thickness of bottom copper; in the tin stripping process, the process is operated according to normal tin stripping parameters.

And S111, performing detection.

And S112, solder resisting.

And S113, characters.

And S114, molding.

And S115, electrically testing.

S116，OSP。

And S117, final inspection.

And S118, packaging.

The above-mentioned well check, resistance welding, characters, shaping, electricity survey, final inspection and packing are all operated according to the conventional production parameters of the circuit board, belong to the conventional technical means in this field, and are not described herein again.

Compared with the prior art, the printed circuit board production process for the middle groove of the IC bonding pad has the following advantages:

1. in the primary milling process, a special aluminum substrate milling cutter is adopted for primary milling, and the parameters of the primary milling are adjusted. The main shaft rotation speed of the common routing board is 3.5 revolutions/min; the lower cutter speed is 0.8 m/min; the advancing speed is 0.5m/min, the rotating speed of the main shaft is improved by 20%, the advancing speed is reduced by 30% -50%, the feed speed is reduced by 20% -40%, and meanwhile, a phenolic aldehyde cover plate is required to be added during one-time milling, and the phenomenon that copper sheets at the edges of IC pins are rolled up only slightly after one-time milling.

2. After one-time routing, the abrasive belt grinding process is added, and the flash of routing grooves at one time is removed, so that the problems of uneven IC pins and undercut of the edge of an IC pad caused by rolling up of copper sheets at one-time routing can be solved.

3. The method and the device have the advantages that two different types of pattern transfer procedures, namely wet ink pattern transfer (first pattern transfer) + dry film pattern transfer (second pattern transfer), are set, so that one pattern transfer in the prior art, namely dry film pattern transfer, is replaced, and the technical problems of short circuit among IC pins and IC edge complementary etching of a slot edge are solved.

Particularly, wet ink is adopted for pattern transfer in the first pattern transfer, the pattern transfer only aims at an IC area and a slotting area, and the combination of the wet ink and a board surface is far better than the combination force of a dry film and the board surface, so that the problems of short circuit and IC edge repair corrosion at the edge of a slot hole caused by the fact that a liquid medicine penetrates through the slot hole back and forth in the electroplating process and the dry film at the edge of the slot hole is loosened are solved;

the second pattern transfer adopts a dry film to carry out pattern transfer, and the pretreatment needs to be carried out by adopting acidic coarsening liquid medicine aiming at the areas outside the IC area and the slotting area; the wet ink is prevented from being damaged by grinding the plate.

Although the present application is disclosed above, the present application is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present disclosure, and it is intended that the scope of the present disclosure be defined by the appended claims.

Claims

1. A production process of a printed circuit board with a groove in the middle of an IC bonding pad is characterized by comprising the following steps:

step one, routing a board;

step three, grinding the plate;

fifthly, transferring the graph for the second time; transferring dry film patterns aiming at other positions of the circuit board except for the position of the IC bonding pad and the position of the slot; wherein, the graph of the second graph transfer is connected with the graph of the first graph transfer; the connection part of the graph of the second graph transfer and the graph of the first graph transfer is partially overlapped;

specifically, a coarsening liquid medicine is adopted for pattern transfer pretreatment;

step six, electroplating the pattern;

step seven, alkaline etching;

step eight, etching the subsequent steps.

2. The process of claim 1, wherein the routing step comprises: cutting, drilling, depositing copper and electrifying a plate; the etching subsequent step comprises: detecting, welding resistance, character, forming, electrical testing, OSP, final inspection and packaging.

3. The process for manufacturing a printed circuit board with a groove in the middle of an IC pad according to claim 1, wherein in the second step, a phenolic cover plate is added during routing.

4. The process for manufacturing a printed circuit board with a groove in the middle of an IC pad according to claim 1, wherein in the fourth step, a pre-processing of pattern transfer is performed by adopting a plate grinding and volcanic ash mode.

5. The process for manufacturing a printed circuit board with a slot in the middle of an IC pad according to claim 4, wherein in the fourth step, the thickness of the ink is 25 μm to 35 μm when the wet ink is printed, the energy is greater than or equal to 7 grids when the wet ink is exposed, the exposure precision is controlled within 25 μm, and the developing speed is 3 m/min.

6. The process for manufacturing a printed circuit board with a slot in the middle of an IC pad according to claim 1, wherein in the fifth step, the energy is greater than or equal to 7 grids during exposure, the exposure precision is controlled within 25 μm, and the developing speed is 3.5 m/min.

7. The process of claim 2, wherein in the board circuit, the thickness is increased by 30-60% of the basic copper thickness.

8. The process for manufacturing a printed circuit board with a groove in the middle of an IC pad according to claim 1, wherein in the second step, the rotating speed of a main shaft for routing the board is increased by 20%, the advancing speed is reduced by 30% -50%, and the feeding speed is reduced by 20% -40%.