TWI387422B - Method for manufacturing printed circuit board - Google Patents

Description

Circuit board manufacturing method

The present invention relates to the field of printed circuit boards, and more particularly to a method of fabricating a circuit board having an interlayer conduction structure.

Printed circuit boards have been widely used due to their high assembly density. For applications on high-density interconnect boards, see the literature Takahashi, A.Ooki, N.Nagai, A.Akahoshi, H.Mukoh, A.Wajima,M.Res.Lab.,High density multilayer printed circuit board for HITAC M -880, IEEE Trans. on Components, Packaging, and Manufacturing Technology, 1992, 15(4): 418-425. Flexible circuit boards have recently developed rapidly due to their small size and light weight, which can be freely bent, wound or folded.

In the prior art, the interlayer conduction structure of the board was fabricated as follows. First, a substrate is provided. The substrate is usually composed of a copper clad plate, and includes an insulating layer and a copper foil layer formed on both surfaces of the insulating layer. Then, two copper foils are required in the substrate by mechanical punching or laser hole forming. The layer needs to be turned on to form a via hole; finally, the formed via hole is metallized. The metallization of the via hole is generally divided into two steps: in the first step, the copper is chemically deposited on the inner wall of the through hole, so that a conductive layer is formed on the inner wall of the through hole. In the second step, the copper layer formed on the inner wall of the through hole is thickened to a required size by electroplating to ensure that it can conduct the two copper foil layers and meet the needs of the circuit board resistance.

However, in the above manufacturing method, the mechanical drill is formed with respect to the laser hole. The equipment of the hole is relatively low in price, and it consumes a large amount of consumables such as drill pins and pads during the drilling process. In addition, the chemical copper deposition and copper plating performed in the process of through-hole metallization are all wet processes, and the process parameters are not easy to control. The application of the reagents in the above process is easy to pollute the environment, and the process time is long, affecting the circuit. The efficiency of board production.

In view of the above, it is necessary to provide a method for manufacturing a circuit board that can simplify the process of inter-layer conduction between boards to improve the efficiency of circuit board fabrication.

A method of fabricating a circuit board will be described below by way of example.

A circuit board manufacturing method includes the steps of: providing an insulating substrate, wherein the insulating substrate has opposite first and second surfaces; and providing a plurality of metal columns, each of the metal columns having a first end surface and a second end surface; The plurality of metal pillars are pressed into the insulating substrate such that a first end surface of each metal pillar is exposed from a first surface side of the insulating substrate, and a second end surface of each metal pillar is exposed from a second surface side of the insulating substrate; Forming a first conductive line on the first surface of the insulating substrate, and forming a second conductive line on the second surface, the first end surface of each metal column is in contact with the first conductive line, and the second end surface of each metal column is Contacting the second conductive line.

Compared with the prior art, the circuit board provided by the technical solution adopts the method of pressing the metal column into the insulating substrate to realize the metallization of the opening and the hole at the same time, without mechanical drilling or laser hole forming and then adopting The method of electroless plating and electroplating to metallize the holes can shorten the production time of the circuit board, reduce the production cost, and reduce the pollution to the environment.

The method for fabricating the circuit board provided by the technical solution is further described below with reference to the accompanying drawings and embodiments.

A method for fabricating a circuit board provided by an embodiment of the present technical solution includes the following steps: Referring to FIG. 1, a first step, an insulating substrate 100 is provided.

The insulating substrate 100 is made of a material for making a circuit board insulating layer. In the present embodiment, the insulating substrate 100 is made of polyimide. The insulating substrate 100 has a first surface 110 and a second surface 120 opposite to each other. The first surface 110 and the second surface 120 are parallel to each other, and the first surface 110 and the second surface 120 are used to form a conductive line. The thickness of the insulating substrate 100, that is, the distance between the first surface 110 and the second surface 120 can be selected according to the thickness of the circuit board that is actually needed.

Referring to FIG. 2, the second step provides a plurality of metal posts 200.

The metal post 200 is used for pressing into the insulating substrate 100, and both ends of the metal post 200 are exposed from the first surface 110 and the second surface 120 of the insulating substrate 100 for conduction to be subsequently formed on the first surface 110 and the second surface. 120 conductive lines.

The metal post 200 is a solid cylinder and may have a shape such as a cylinder or a polygonal prism. The metal post 200 has a first end surface 210 and a second end surface 220 opposite to each other. The height of the metal post 200, that is, the distance between the first end surface 210 and the second end surface 220 is equal to or slightly larger than the thickness of the insulating substrate 100. The material of the metal pillar 200 can be various metals having good electrical conductivity, such as copper, aluminum or silver. The metal column 200 can be produced by casting or die casting. . In order to provide the strength of the metal column 200, the surface of the metal column 200 may be treated, and the surface of the metal column 200 may be specifically treated by carbonization or nitriding. In this embodiment, the metal post 200 is cylindrical, and its diameter can be set according to the requirements of the circuit for conducting the conduction region, so that it can meet the performance of the resistance of the circuit board, etc., preferably, the diameter of the metal post 200. Not less than 100 microns.

Referring to FIG. 3 and FIG. 4, in the third step, the metal post 200 is pressed into the insulating substrate 100 in a region where conduction is required.

According to the needs of the fabricated circuit board, the metal pillar 200 is pressed perpendicularly to the first surface 110 in a region where the conductive substrate 100 is required to be turned on, so that the metal pillar 200 is embedded in the insulating substrate 100, and the first end surface of the metal pillar 200 is made. 210 is flush with the first surface 110 of the insulating substrate 100, and the second end surface 220 is flat with the second surface 120. The diameter of the metal posts 200 pressed into the insulating substrate 100 may be different to meet different electrical performance requirements.

Referring to FIG. 5, in the embodiment, the metal post 200 is pressed into the insulating substrate 100 by using the press-in device 10. The press-in device 10 includes a main shaft 11, a pressing device 12, a carrying platform 14, and a control driving device (not shown). The carrier 14 is horizontally disposed, and the carrier 14 is used to carry the insulating substrate 100 and position the insulating substrate 100. The main shaft 11 is perpendicular to the stage 14 and opposed to the stage 14, and the pressing device 12 is mounted on the surface of the main shaft 11 opposite to the stage 14. Inside the main shaft 11, a guide groove 13 is opened, and the direction in which the guide groove 13 extends is parallel to the main shaft 11. The guide groove 13 is for accommodating the metal post 200 and causing the metal post 200 to extend along the guide groove 13. The guide groove 13 communicates with the pressing device 12 such that the metal post 200 in the guide groove 13 is sequentially introduced into the lower pressing device 12 and exposed from the pressing device 12. First, the insulating substrate 100 is fixed to the carrier. On the stage 14, then by controlling the driving device, the driving device drives the spindle 11 to move within the corresponding range of the carrier 14, and controls the pressing device 12 to move relative to the spindle 11 to generate an impact force, thereby causing the metal post 200 to be The set program is pressed into a position where the insulating substrate 100 is required to be turned on.

Of course, it is also possible to press the metal post 200 into the insulating substrate 100 in a region where it is desired to conduct electricity manually or by other means.

Referring to FIG. 6 to FIG. 9 together, in the fourth step, a conductive line is formed on the surface of the insulating substrate 100 with the metal post 200 pressed thereinto, thereby obtaining the circuit board 400.

First, the first copper foil layer 310 is pressed on the first surface 110, and the second copper foil layer 320 is pressed on the second surface 120.

The first copper foil layer 310 is adhered to the first surface 110, the second copper foil layer 320 is adhered to the second surface 120, and the insulating substrate of the first copper foil layer 310 and the second copper foil layer 320 is bonded thereto. The heating and pressing are performed, so that the first copper foil layer 310 and the second copper foil layer 320 are integrally formed with the insulating substrate 100, and the first end surface 210 of each metal pillar 200 is in contact with the first copper foil layer 310. The second end face 220 of each of the metal posts 200 is in contact with the second copper foil layer 320.

Then, the first copper foil layer 310 is formed into a first conductive line 330, and the second copper foil layer 320 is formed into a second conductive line 340.

In this embodiment, the first conductive line 330 and the second conductive line 340 are fabricated by image transfer technology. Specifically, the photoresist layer 350 is first formed on the first surface 110 and the second surface 120. Then, the photoresist layer 350 is exposed and developed such that the photoresist remains on the first surface 110 and the second surface 120. The shape of 360 is the same as the shape of the conductive line such that the first copper foil layer 310 and the second copper foil layer 320 are exposed from the residual photoresist 360. Finally, the first copper foil layer 310 and the second copper foil layer 320 are etched to obtain a first conductive line 330 and a second conductive line 340.

The first conductive line 330 and the second conductive line 340 are electrically connected to each other by the metal pillars 200 in the insulating substrate 100, thereby obtaining a circuit board 400 having an interlayer conduction structure.

The conductive line can be formed on the surface of the insulating substrate 100 with the metal pillars 200 pressed. The conductive lines can be directly printed on the first surface 110 and the second surface 120 by inkjet printing. According to a preset circuit, the conductive ink is sprayed on the first surface 110 and the second surface 120 by using a printer to obtain the first conductive line 310 and the second conductive line 320. The conductive lines that have been fabricated can also be directly bonded to the first surface 110 and the second surface 120. In addition, the first substrate including the first insulating layer and the first conductive line 330 is pressed against the first surface 110 of the insulating substrate 100, and the first conductive line 330 is in contact with the first surface 110, thereby insulating The first surface 110 of the substrate 100 forms the first conductive line 330, and the second substrate including the second insulating layer and the second conductive line 340 is pressed against the second surface 120 of the insulating substrate 100, and the second surface is The conductive line 340 is in contact with the second surface 120 to form the second conductive line 340 on the second surface 120 of the insulating substrate 100, thereby obtaining the circuit board 400.

Referring to FIG. 10, the second insulating substrate 500 with the metal pillars 200 pressed into the surface of the first conductive line 330 of the circuit board 400 may be further pressed, and a third conductive line may be formed on the surface of the second insulating substrate 500 that is pressed. 600, making The third conductive line 600 and the first conductive line 330 are electrically connected to each other by the metal pillars 200 of the second insulating substrate 500, so that more layers of the circuit board 700 having the interlayer conduction structure can be obtained.

The manufacturing method of the circuit board provided by the technical solution adopts the method of pressing the metal column into the insulating substrate to realize the metallization of the opening and the hole at the same time, without using mechanical drilling or laser forming holes and then performing holes by electroless plating and electroplating. The metallization process can shorten the board production time and production cost and reduce environmental pollution.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧Indentation device

11‧‧‧ Spindle

12‧‧‧Under pressure device

14‧‧‧Loading station

13‧‧‧ Guide groove

100‧‧‧Insert substrate

110‧‧‧ first surface

120‧‧‧second surface

200‧‧‧ metal column

210‧‧‧ first end face

220‧‧‧second end face

310‧‧‧First copper foil layer

320‧‧‧Second copper foil layer

330‧‧‧First conductive line

340‧‧‧Second conductive line

350‧‧‧ photoresist layer

360‧‧‧ Remaining photoresist

400, 700‧‧‧ circuit board

500‧‧‧second insulating substrate

600‧‧‧ Third conductive line

FIG. 1 is a schematic diagram of an insulating substrate for manufacturing a circuit board according to an embodiment of the present technical solution.

2 is a schematic diagram of a metal post for fabricating a circuit board provided by an embodiment of the present technical solution.

FIG. 3 is a schematic perspective view of the metal post provided by the embodiment of the present invention after being pressed into the insulating substrate.

Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3.

FIG. 5 is a schematic view showing a method of pressing a metal column into an insulating substrate by using a press-in device according to an embodiment of the present technical solution.

FIG. 6 is a schematic view showing a copper foil layer formed on the surface of an insulating substrate according to an embodiment of the present technical solution.

FIG. 7 is a schematic view showing a photoresist layer formed on a surface of a copper foil layer according to an embodiment of the present technical solution.

FIG. 8 is a schematic view of the embodiment of the present technical solution after development on the photoresist layer.

FIG. 9 is a schematic diagram of a circuit board produced by the embodiment of the technical solution in the technical solution.

FIG. 10 is a schematic diagram of another circuit board produced by the embodiment of the technical solution in the technical solution.

200‧‧‧ metal column

330‧‧‧First conductive line

340‧‧‧Second conductive line

400‧‧‧ circuit board

Claims (9)

A circuit board manufacturing method includes the steps of: providing an insulating substrate, wherein the insulating substrate has opposite first and second surfaces; and providing a plurality of metal pillars, each of the metal pillars having a first end surface and a second end surface The plurality of metal columns are formed by casting or die casting, and the surface of the plurality of metal columns is carbonized or nitrided to improve the strength of the plurality of metal columns; and the plurality of metal columns are Pressing into the insulating substrate such that the first end surface of each metal post is exposed from the first surface side of the insulating substrate, and the second end surface of each metal post is exposed from the second surface side of the insulating substrate; After the pillar is pressed into the insulating substrate, a first conductive line is formed on the first surface of the insulating substrate, and a second conductive line is formed on the second surface, and the first end surface of each metal pillar is in contact with the first conductive line. A second end surface of each of the metal posts is in contact with the second conductive line. The method of manufacturing the circuit board of claim 1, wherein a distance between the first end surface and the second end surface is equal to or greater than a distance between the first surface and the second surface. The method of manufacturing a circuit board according to the first aspect of the invention, wherein the plurality of metal pillars are pressed into the insulating substrate in a direction perpendicular to the first surface and the second surface. The method of manufacturing the circuit board according to the first aspect of the invention, wherein the plurality of metal pillars are made of copper, aluminum or silver. The method for fabricating a circuit board according to claim 1, wherein the forming a first conductive line on the first surface and the second surface on the second surface The conductive circuit includes the steps of: pressing the first copper foil layer on the first surface, pressing the second copper foil layer on the second surface; and forming the first copper foil layer into the first conductive line by image transfer, and the second The copper foil layer is formed into a second conductive line by image transfer. The method for fabricating a circuit board according to claim 1, wherein the first conductive line is formed on the first surface by inkjet printing, and the second is performed by inkjet printing. A conductive line is formed on the second surface. The method of manufacturing the circuit board of claim 1, wherein the first conductive line is formed by bonding the completed conductive line to the first surface, and the second conductive line is The completed conductive trace is formed on the second surface. The method of manufacturing the circuit board of claim 1, wherein the first substrate including the first insulating layer and the first conductive line is pressed against the first surface of the insulating substrate, and the first conductive is made The circuit is in contact with the first surface to form the first conductive line on the first surface of the insulating substrate, and the second substrate including the second insulating layer and the second conductive line is pressed against the second surface of the insulating substrate And contacting the second conductive line with the second surface to form the second conductive line on the second surface of the insulating substrate. The method of manufacturing the circuit board of claim 1, wherein the first conductive line is formed on the first surface of the insulating substrate, and the second conductive line is formed on the second surface, after the first conductive Forming another insulating substrate with a plurality of metal columns on the line, and forming a third conductive line on the surface of the other insulating substrate, so that the third conductive line and the first conductive line The circuit is electrically connected to each other by a plurality of metal pillars in the second insulating substrate.