KR20000025528A - Method of electrical interlayer connection of multi-layered printed circuit board - Google Patents

Abstract

PURPOSE: A method of electrical interlayer connection of multi-layered printed circuit board is provided to manufacture an interlayer via hole for electrically connecting printed circuits of at least three layers. CONSTITUTION: A method of electrical interlayer connection of multi-layered printed circuit board comprises the steps of: forming a printed circuit board composed of a third, a fourth and a fifth layers; corroding circuits and pads of the second and the fifth layers as well as a copper film in the center of a pad of the second layer in which a via hole will be formed, to electrically connect a first, the second and the third layers; forming the first and a sixth layers by multi-laying an insulation layer and a copper layer on the entire surface in high temperature and pressure; corroding the copper layer of the first and the sixth layers according to a predetermined pattern to make an interlayer via hole; eliminating epoxy by irradiating laser beam into the corroded copper layer to manufacture the interlayer via hole; and applying copper layer, by electrical plating, on the inner wall of the interlayer via hole formed in the first, the second and the third layers for electrical connection.

Description

Interlayer electrical connection method of multilayer printed circuit board

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interlayer electrical connection method of a multilayer printed circuit board, and more particularly, to an interlayer via hole manufacturing method for simultaneously electrically connecting a first layer, a second layer, and a third layer.

In a multilayer printed circuit board, a via hole is formed in an interlayer insulator to electrically connect each layer having a patterned printed circuit, and an electroplated conductive film or a paste is pasted on the inner wall of the via hole. Doing.

However, as the density of devices mounted per unit area of a multilayer printed circuit board increases, a method for simultaneously electrically connecting three or more layers of multilayer printed circuits as well as electrical connections between two layer wirings has been studied.

In general, in order to form via holes in a multilayer printed circuit board, the holes are drilled by laser drilling or plasma etching. In order to electrically connect three or more printed circuit layers through the via holes in a vertical direction, the first layer may include: After forming the via holes between the second layers and applying the electroplating film, a technique of forming via holes in the second layer and the third layer and electrically connecting them again has been used.

In the manufacture of a multilayer printed circuit board, a conventional technique used to make electrical connections of three or more layers of printed circuits at the same time in the vertical direction will be described with reference to FIGS. 1A to 1C.

According to the prior art shown in FIG. 1A, the printed circuit pattern 10 of the second layer and the printed circuit pattern 11 of the third layer are electrically connected by a copper film plated on the inner wall of the via hole. . Meanwhile, referring to FIG. 1B, laser drilling is performed on the pattern 12 formed through the wet chemical corrosion process on the copper foil of the first layer to be electrically connected to the second and third layers that are electrically connected. To remove the epoxy from the via hole. Subsequently, as shown in FIG. 1C, copper plating is performed to electrically conduct the first layer, the second layer, and the third layer.

However, as described above, the manufacturing method for the electrical connection of the three-layer wiring according to the prior art comprises the steps of: performing laser drilling to form via holes on the second layer; Performing copper plating for electrical connection of the second layer and the third layer; Performing laser drilling to form via holes on top of the first layer; There is a complexity in the process of repeatedly performing the copper plating for the electrical connection between the first layer and the second layer.

Accordingly, a first object of the present invention is to provide a method for manufacturing an interlayer via hole of a multilayer printed circuit board for electrically connecting a printed circuit of three or more layers.

In addition to the first object, the second object of the present invention is to simplify the manufacturing of the interlayer via hole for electrically connecting three or more layers of printed circuits, so that only one laser drilling step and one copper plating step An interlayer via hole manufacturing method capable of simultaneously electrically connecting two or more printed circuits is provided.

1A to 1C are cross-sectional views showing a method for manufacturing an interlayer via hole of a multilayer printed circuit board according to the prior art.

1A to 2G are cross-sectional views showing a method for manufacturing an interlayer via hole of a multilayer printed circuit board according to the present invention.

Description of the main parts of the drawing

50: epoxy or glass fiber

51: copper foil

61: RCC

In order to achieve the above object, the present invention provides a method for manufacturing an interlayer via hole of a multilayer printed circuit board, comprising: forming a four-layer printed circuit board including a second layer, a third layer, a fourth layer, and a fifth layer; Corroding the circuits and pads of the second and fifth layers together with the copper foil of the central portion of the second layer pad to which the via holes are to be formed to electrically connect the first and second layers; Stacking an insulating film and a copper foil at high temperature and high pressure on the resultant to form a first layer and a sixth layer; Corroding the copper foils of the first and sixth layers according to a predetermined pattern to form interlayer via holes; Removing the epoxy by irradiating a laser beam to a portion where copper foil has been corroded to form the interlayer via hole; A method of manufacturing an interlayer via hole of a multilayer printed circuit board, the method comprising: applying copper foil to the inner wall of the interlayer via hole formed in the first layer, the second layer, and the third layer for electrical connection. do.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a method for manufacturing an interlayer via hole of a multilayer printed circuit board according to the present invention will be described in detail.

2A to 2G are diagrams showing a procedure of an interlayer via hole manufacturing process of a multilayer printed circuit board according to the present invention. Referring to FIG. 2A, the third conductive layer 51 and the fourth layer 52 of the multilayer printed circuit board are formed by patterning the first conductive layer 51 on the upper and lower portions of the first insulating layer 50. According to a preferred embodiment of the present invention, the first insulating film 50 may use an insulating film composed of epoxy and glass fiber, and the first conductive film may use a copper film. .

In addition, as a preferred embodiment of the present invention, the first insulating film to which the first conductive film is bonded is a copper clad laminate (CCL) in which copper foil is bonded to the upper and lower portions of the insulating layer made of epoxy and glass fiber. Can be used. Next, a four-layer printed circuit board having the second layer 53 and the fifth layer 54 is produced by laminating the second insulating films 55 and 56 and the second conductive films 53 and 54 at high temperature and high pressure.

Figure 2b is a preferred embodiment according to the present invention, showing the process steps to selectively corrode the copper foil of the second layer and the fifth layer. Referring to FIG. 2B, the copper foil of the center portion 60 of the pad of the second layer of the first layer, the second layer, and the third layer via hole is subjected to selective corrosion of the circuits and the pads of the second and fifth layers. Corrode together.

FIG. 2C is a diagram illustrating a process step of stacking the third insulating layers 61 and 62 and the third conductive layers 63 and 64 at high temperature and high pressure to form the first and sixth layer circuits. Referring to FIG. 2C, as a preferred embodiment of the present invention, the third insulating layers 61 and 62 and the third conductive layers 63 and 64 may be made of resin coated copper (RCC) or PREPREG (cured resin in glass fiber). Can be laminated using).

Figure 2d is a preferred embodiment according to the invention, RCC or PREPREG (61, 62) and copper foil (63, 64) for the CCL formed second, third, fourth, fifth layer by selective corrosion ) Shows a step of laminating.

FIG. 2E illustrates a process step of corroding the copper foils of the first and sixth layers at positions where a laser via is to be formed by a selective corrosion method. Referring to FIG. 2E, a via contact window 70 for connecting the first layer and the second layer, a via contact window 71 for electrically connecting the first layer and the third layer, and the first layer and the first layer It can be seen that the via contact window 72 for simultaneously electrically connecting the second layer and the third layer is formed.

FIG. 2F illustrates a process step for removing epoxy in a portion of a via hole by irradiating a CO ₂ laser beam to a via contact window formed by a selective corrosion method as a preferred embodiment according to the present invention.

FIG. 2G illustrates a process step in which the fourth conductive film 78 is applied to the entire interlayer via hole and the outer layer copper foil formed to electrically connect the inner layer copper foils 73, 74, 75, 76 and the outer layer copper foil 77. The figure shown. According to a preferred embodiment of the present invention, the fourth conductive film 78 may be formed through copper plating or a copper paste process.

Referring to FIG. 2G, the first layer and the second layer 73, the first layer and the third layer 74, and the first layer, the second layer, and the third layer 75 of the present invention are simultaneously connected. Unlike the prior art, the method for manufacturing a via hole can connect a multilayer printed circuit with one via formation and copper plating without further processing. In addition, when the above-described method for manufacturing a via hole of the present invention is extended, three or more printed circuits can be connected to a multilayer printed circuit board in one via formation process and a copper plating process.

The foregoing has outlined rather broadly the features and technical advantages of the present invention to better understand the claims of the invention which will be described later. Additional features and advantages that make up the claims of the present invention will be described below. It should be appreciated by those skilled in the art that the conception and specific embodiments of the invention disclosed may be readily used as a basis for designing or modifying other structures for carrying out similar purposes to the invention.

In addition, the inventive concepts and embodiments disclosed herein may be used by those skilled in the art as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. In addition, such modifications or altered equivalent structures by those skilled in the art may be variously changed, substituted, and changed without departing from the spirit or scope of the invention described in the claims.

The method for manufacturing an interlayer via of a multilayer printed circuit board according to the present invention as described above includes a copper foil of a center portion of a pad of a second layer to form a via hole in order to electrically connect the first layer to the second layer and the third layer. After corroding the circuits and pads of the second and fifth layers together, removing the epoxy by irradiating a laser beam to the corroded portions of the copper foil to form an interlayer via hole; The application of copper foil to the inner wall of the interlayer via hole formed in the second and third layers by electroplating consists of only one laser drilling step and copper plating step, thereby simplifying the multilayer printed circuit board manufacturing process step, We can expect the cost savings of printed circuit board production and the improvement of production yield.

Claims (4)

In the method of manufacturing an interlayer via hole of a multilayer printed circuit board, Forming a four-layer printed circuit board composed of a second layer, a third layer, a fourth layer, and a fifth layer; Corrosing the circuits and pads of the second and fifth layers together with the copper foil of the central portion of the pad of the second layer to form the via holes for electrically connecting the first layer to the second and third layers. ; Stacking an insulating film and a copper foil at high temperature and high pressure on the resultant to form a first layer and a sixth layer; Corroding the copper foils of the first and sixth layers according to a predetermined pattern to form interlayer via holes; Removing the epoxy by irradiating a laser beam to a portion where copper foil has been corroded to form the interlayer via hole; Applying copper foil to the inner wall of the interlayer via hole formed in the first, second and third layers for electrical connection by electroplating An interlayer via hole manufacturing method of a multilayer printed circuit board comprising a. The method of claim 1, wherein the forming of the first layer and the sixth layer by laminating the insulating film and the copper foil at high temperature and high pressure on the resultant comprises laminating the copper foil at high temperature and high pressure with either RCC or PREPREG. Method for manufacturing interlayer via holes in a printed circuit board. The method of claim 1, wherein the removing of the epoxy by irradiating the laser beam with the corroded portion to form the interlayer via hole comprises: removing the CO ₂ laser beam with the corroded portion of the copper foil to form the interlayer via hole. A method of manufacturing an interlayer via hole in a multilayer printed circuit board comprising the step of removing the epoxy by irradiation. According to claim 1, wherein the step of removing the epoxy by irradiating a laser beam to the portion where the copper foil is corroded to form the interlayer via hole, the insulating film and the copper foil laminated on the resultant at high temperature and high pressure layer 0 and the seventh layer Forming a; Further comprising the step of corroding the copper foils of the 0th and 7th layers according to a predetermined pattern to form an interlayer via hole, wherein the four layers are electrically connected simultaneously without further processing. Method for manufacturing via holes.