JPH10335776A - Printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board, in which a remaining air of an opening part is removed when electric component is connected to the printed circuit board via an anisotropic conductive film, and reliability of electric connection between wiring patterns and electronic component is enhanced. SOLUTION: In a printed circuit board, a solder resist layer 13 having an opening part 16 is adhered onto an insulation substrate 11 forming a specific wiring pattern 12, and electronic component is connected to a connection part of the wiring patterns 12 facing the opening part 16 via an anisotropic conductive film 14. An air extracting hole 15 is provided in the insulation substrate 11 facing the opening part 16 of the solder resist layer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for electrically and mechanically joining a chip-like electronic component such as a semiconductor device to a wiring pattern on an insulating substrate via an anisotropic conductive film. It relates to a suitable printed circuit board.

[0002]

2. Description of the Related Art Conventionally, as a method of electrically connecting an electronic component, for example, a semiconductor element, to a printed circuit board, a method such as so-called flip chip bonding is generally used, and a metal connection terminal of the semiconductor element is used. (Commonly called a bump) is superimposed on the wiring pattern of the printed circuit board, and thermocompression-bonded therebetween through an anisotropic conductive film in which conductive particles are dispersed in an insulating adhesive.
The corresponding parts (between the bump and the conductive pattern) are connected by conductive particles, and the parts that do not correspond are electrically separated by an insulating adhesive, that is, electrically anisotropic connection is made. There is a method of performing mechanical bonding as well as mechanical bonding.

FIGS. 8A to 8C show a process for connecting a semiconductor element, which is one of electronic components, to an anisotropic conductive film on a printed circuit board. FIG. 9 shows a process for mounting the anisotropic conductive film on the printed circuit board. 8B is a sectional view taken along line BB of FIG. 8B. FIG.
FIG. 8C shows a semiconductor device connected to a printed circuit board.
2 shows a C-C cross section of FIG.

[0004] As shown in FIG. 8A, a predetermined wiring pattern 12 is formed on one surface of an insulating substrate 11, and the wiring pattern 1 is formed.
A printed circuit board 17 having a solder resist layer 13 formed on the entire surface except for a connection portion 12a with the second semiconductor element 20 is provided.

When mounting the anisotropic conductive film 14 on the printed circuit board 17, the opening 16 in the solder resist layer 13 is
Smaller than the wiring pattern 12 and placed directly on the wiring pattern 12,
Since the wiring pattern 12 is cracked and breaks due to contact with the end of the anisotropic conductive film 14, the anisotropic conductive film 14 is connected to the opening of the solder resist layer 13 as shown in FIGS. 8B and 9. 16 and is mounted so as to straddle the solder resist layer 13. And anisotropic conductive film 14
Is placed on the solder resist layer 13, the semiconductor element 20 on which the metal connection terminals (bumps) 21 are formed as shown in FIGS. 8C and 10 is heated and pressed to connect the connection portions 12a of the wiring pattern 12. Connected. At this time, the anisotropic conductive film 14 also serves as a mechanical sealing resin for electrically connecting the wiring pattern 12 and the semiconductor 20 and maintaining its reliability.

[0006]

In the conventional method for connecting the printed circuit board 17 and the semiconductor element 20, the solder resist layer 13 and the insulating substrate 11 have a thickness of 10 to 20 μm.
When the anisotropic conductive film 14 is heated and pressed against the insulating substrate 11 as it is, the opening 16 of the solder resist layer 13 is sealed, so that as shown in FIG. Air bubbles of air 30 remain. If the residual air 30 is used in a confined state as described above, the connection between the wiring pattern 12 and the bump 21 is cut off with the elapse of time, causing a serious problem in reliability as an electric circuit. The present invention is to provide a printed circuit board that eliminates such residual air and improves the reliability of electrical connection between a wiring pattern and an electronic component.

[0007]

A printed circuit board according to the present invention has a structure in which an air vent hole is provided in an insulating substrate facing an opening of a solder resist layer.

In such a configuration, when connecting the electronic component to the printed circuit board, the residual air in the opening is completely removed from the air vent hole of the insulating substrate, and the bump of the electronic component and the wiring pattern of the printed circuit board are removed. Connection is good and reliability is hardly lost even after long use.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A printed circuit board according to the present invention has a solder resist layer having an opening formed on an insulating substrate on which a predetermined wiring pattern is formed. In the printed circuit board connected through the anisotropic conductive film to the connection part of the wiring pattern facing the, the insulating substrate facing the opening of the solder resist layer,
The air vent hole is provided.

[0010] The printed circuit board according to the present invention is configured such that, in the printed circuit board, air vent holes are provided at positions corresponding to the corners of the opening.

Hereinafter, description will be made with reference to the drawings. FIG.
It is a plan view of an example of a printed circuit board according to the present invention,
FIG. 2 is a sectional view taken along line AA of FIG. The printed circuit board 10 has a wiring pattern 12 formed on one surface of an insulating substrate 11, and an entire surface of the printed circuit board 10 excluding a required area including a connection portion 12 a of the wiring pattern 12 (connection portion to which electronic components are connected). Then, a solder resist layer 13 is formed by deposition.
The required area, that is, the opening 16 of the solder resist layer 13
Air vent hole 1 penetrating to the lower part of insulating substrate 11 facing
5 is provided.

The position of the air vent hole 15 may be appropriately provided in the opening 16 of the solder resist layer 13 at a position where air remains when the anisotropic conductive film 14 is press-bonded.
Since the opening 16 of the solder resist layer 13 is square, air is likely to remain at the four corners of the opening 16, so it is preferable to provide the air vent holes 15 at the four corners.

The size, shape and the like of the air vent hole 15 may be appropriately selected according to the amount of residual air. In general, when the hole is opened by a drill or the like, the diameter is preferably about 0.5 to 1 mmφ.

An electronic component, for example, a semiconductor element is connected to the printed circuit board 10 in the following manner.

First, as described above, the anisotropic conductive film 14 is placed so as to cover the opening 16 of the solder resist layer 13. Then, as shown in FIG.
Preferably, the anisotropic conductive film 14 is heated and pressed by using an attaching head 40 to which a rubber 41 having a convex central portion is attached. At this time, the air 30 at the center of the area facing the opening 16 is driven to the corner (see FIG. 4), and the air hardly remains at the center. The air 30 that has been displaced to this corner is filled with air vent holes 15 formed in the corners of the opening 16.
From the substrate, and the adhesion of the anisotropic conductive film 14 is completed as shown in FIG.

Next, as shown in FIG. 6, the semiconductor element is directly pressurized in a heated state, and the metal connection terminals (bumps) 21 of the semiconductor element 20 are connected to the wiring pattern 1 of the printed circuit board 10.
2, the semiconductor element 20 and the wiring pattern 12 are connected via the anisotropic conductive film 14.

As shown in FIG. 7, the anisotropic conductive film 14 is pressurized by a metal bonding head 40 having a flat tip, and is pressed into the opening 16 of the solder resist layer 13.
After that, the semiconductor element is placed on the anisotropic conductive film 14,
Similarly, by applying pressure, the metal connection terminal (bump) can be pressed into contact with the connection portion 12a of the wiring pattern 12 via the anisotropic conductive film 14. However, it is more preferable to use, as the pasting head 40, a pasting head in which rubber 41 is pasted to the tip end portion shown in FIG. 3 because the residual air 30 can be reliably extracted from the air vent hole 15 provided at the corner. .

As described above, according to the printed circuit board 10 of the present invention, the air vent holes 15 are preferably formed at the four corners of the insulating substrate 11 in the region facing the openings 16 of the solder resist layer 13 of the printed circuit board 10. Is provided, an electronic component such as the semiconductor element 20 is connected to the anisotropic conductive film 14.
, The residual air 30 is completely removed through the air vent hole 15, and the electrical and mechanical connection is improved. In addition, there is no connection failure between the wiring pattern and the bump of the electronic component due to aging due to residual air,
A highly reliable connection is obtained.

The printed circuit board of the present invention is not limited to the above-described example, and may take various other configurations without departing from the gist of the present invention.

[0020]

According to the printed circuit board of the present invention, when an electronic component such as a semiconductor element is connected to the wiring pattern through the anisotropic conductive film in the opening of the solder resist layer, residual air is generated. Is completely removed, so that electrical and mechanical connection is improved. In addition, since connection failure due to aging is eliminated, a highly reliable connection can be obtained. Further, particularly when the air vent hole is provided at a position corresponding to the corner of the opening, the residual air is further reduced, and the electrical and mechanical connection is further completed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of a printed circuit board according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory view (part 1) of a method for connecting an electronic component to a printed circuit board via an anisotropic conductive film according to the present invention.

FIG. 4 is an explanatory view (part 2) of a method for connecting an electronic component to a printed circuit board via an anisotropic conductive film according to the present invention.

FIG. 5 is an explanatory view (part 3) of a method of connecting an electronic component to a printed circuit board via an anisotropic conductive film according to the present invention.

FIG. 6 is an explanatory view (No. 4) of a method for connecting an electronic component to a printed circuit board via an anisotropic conductive film according to the present invention.

FIG. 7 is an explanatory view of another method of pressing an anisotropic conductive film on a printed circuit board according to the present invention.

FIG. 8 is a process diagram for connecting a conventional printed circuit board and a semiconductor element.

FIG. 9 is a sectional view taken along line BB of FIG. 8C.

FIG. 10 is a sectional view taken along line CC of FIG. 8C.

[Explanation of symbols]

10, 17 printed circuit board, 11 insulating board, 12
Wiring pattern, 13 solder resist layer, 14 anisotropic conductive film, 15 air vent hole, 16 opening, 20 semiconductor element, 21 bump, 30 residual air, 40 bonding head, 41 rubber

Claims (2)

[Claims] A solder resist layer having an opening is formed on an insulating substrate on which a predetermined wiring pattern is formed, and an electronic component is connected to a connecting portion of the wiring pattern facing the opening. A printed circuit board connected via an isotropic conductive film, wherein an air vent hole is provided in the insulating substrate facing an opening of the solder resist layer. 2. The air vent hole is provided at a position corresponding to a corner of the opening.
A printed circuit board according to claim 1.