JPS5928996B2 - How to install electronic parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for attaching an electronic component having a large number of terminals, such as an LSI element, to a mounting board, and particularly to a method for attaching a mounting board to an electronic component that has conventionally been used. The present invention provides a new mounting method devised to prevent cracks or damage from occurring due to the difference in coefficient of thermal expansion between the two.

Generally, when electronic components are mounted on a glass substrate, if the coefficient of thermal expansion of the electronic component and that of the substrate are relatively large, cracks will occur in the substrate due to temperature cycles, etc., and the component will be damaged. This is known. For example, as shown in FIG.
A) When attaching the electronic component 2 to the IA with the solder 3, the coefficient of thermal expansion of the glass substrate 1 (90 to 100 x 10-
Electronic component 2, which has a coefficient of thermal expansion relatively close to 7cm/°C), and Tsumeya ceramic component (coefficient of thermal expansion 78×10-'
! , cm/°C), no cracks will occur or parts will be damaged.

Then, the electronic component 2 has a coefficient of thermal expansion (
30×10-cm/°C) is significantly different from that of the board 1, cracks may occur in the board 1 or parts may be damaged.As a method to solve such problems, conventional proposed a mounting method in which a strain absorbing member made of a conductive metal plate formed into a U-shape or the like is interposed between an electronic component terminal and a board terminal to electrically and mechanically connect the two. has been done.

However, in this conventional mounting method, since the strain absorbing member is also used for conducting between the electronic component terminal and the board terminal, for example, when the electronic component is small like an LSI element and has a large number of terminals, In this case, each terminal of the electronic component and the board must be connected one by one using the conductive metal plate, which has the drawback of requiring a great deal of effort and time for installation.

Furthermore, since the pitch between the terminals on the electronic component and the board is very narrow, the conductive metal plate tends to come into contact with the adjacent one, resulting in unreliability. As described above, the conventional mounting method has the fatal drawback of not being able to bond LSI elements.

Therefore, an object of the present invention is to provide a new method for bonding electronic components having a large number of terminals, such as LSI devices, to a board without causing cracks or damage due to differences in thermal expansion. be.

The method of the present invention will be explained in detail below based on the drawings.

In FIG. 2, an electronic component 2 such as a silicon component whose coefficient of thermal expansion is significantly different from that of the substrate 1 is attached to a terminal 1A11A formed by etching or printing a conductor on a glass substrate 1 using solder 3. Glass layers 4, 4 having a thermal expansion coefficient of a material located between the glass substrate 1 and the electronic component 2 and close to that of the glass substrate 1, that is, a thermal expansion coefficient of 75×10-CTrL/° C., on the glass substrate 1; A material is laminated on the layers 4, 4 and has a thermal expansion coefficient that is located between the substrate 1 and the component 2 and is close to that of the component 2, i.e., a thermal expansion coefficient of 50×1.
Another glass layer 5, 5 having a temperature of 0-7 Cm/° C. is formed by printing or vapor deposition to a thickness of about 20 μm each, and a terminal 1A11A is provided on the glass layer 5, 5.

Then, an electronic component 2 is attached to the terminal 1A11A with solder 3.

According to the mounting method of this embodiment, the substrate 1, the glass layer 4,
It is possible to reduce the difference in coefficient of thermal expansion between the glass layer 4 and the glass layer 5, and between the glass layer 5 and the electronic component 2, thereby creating a substantially small difference in the coefficient of thermal expansion between the substrate 1 and the electronic component 2. But it can be connected.

Therefore, the influence of the difference in thermal expansion coefficients between the substrate 1 and the electronic component 2, that is, thermal strain, is significantly alleviated, thereby making it possible to prevent cracks from occurring in the glass substrate 1 and damage to the electronic component 2. . Furthermore, in this embodiment, since the strain absorbing member is made of an insulating and extremely thin layer, there is almost no difference in level between it and the substrate surface. A fine terminal pattern can be formed together with the pattern.

Therefore, it is possible to bond electronic components to this terminal pattern, and it is possible to bond electronic components such as LSI devices with a large number of terminals using conventional bonding methods to prevent cracks and damage due to thermal distortion. It can be mounted on a board without causing any problems, and it is possible to significantly improve reliability and mass productivity in particular. On the other hand, the third
The figure shows another embodiment in which an electronic component 2 such as a silicon component having a coefficient of thermal expansion significantly different from that of the substrate 1 is attached to a terminal 1A11A on a glass substrate 1 with solder 3. The coefficient is glass substrate 1
A glass layer 6 is formed between the electronic component 2 and the glass layer 6 having a thermal expansion coefficient close to that of the electronic component 2, that is, a glass layer 6 having a thermal expansion coefficient much smaller than that of the glass substrate 1. The formation of the layer 6 strengthens the glass substrate 1 by applying compressive stress to the surface of the glass substrate 1;
Terminals 1A1 provided on the glass layers 6, 6
1A, an electronic component 2 is attached with solder 3.

In the method shown in FIG. 3, the glass substrate 1 is strengthened by the glass layer 6 according to the principle of tempered glass, and the thermal expansion coefficient is set between the glass substrate 1 and the electronic component 2, thereby increasing the gap between the substrate and the component. It is possible to achieve the same effects as in the previous embodiment, such as keeping the difference in thermal expansion coefficients small and thereby preventing damage to the component 2.

As described above, according to the method of the present invention, an extremely thin layer of an insulating strain absorbing member is formed on a substrate, a terminal is formed on this extremely thin layer, and an electronic component is attached to the terminal. This makes it possible to prevent cracks and damage to electronic components and the mounting board due to differences in thermal expansion between the electronic components and the mounting board. Terminals can be bonded.

Therefore, the method of the present invention is very effective for mounting electronic components with a large number of terminals, such as LSI devices.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the conventional method of mounting electronic components, Figure 2
The figure is an explanatory diagram showing the mounting method of the present invention, and FIG. 3 is an explanatory diagram showing another embodiment using the same method. 1... Board, 1A... Terminal, 2... Electronic component, 3
...Solder, 4, 5, 6...Glass layer.

Claims (1)

[Claims] 1. In a device in which electronic components are mounted on a mounting substrate such as a glass substrate, an extremely thin layer is formed on the substrate of an insulating member capable of absorbing distortion due to thermal expansion, and A method for attaching an electronic component, characterized in that a terminal is formed on this ultra-thin layer, and the electronic component is attached to the terminal. 2. Claim 1, characterized in that the extremely thin layer of the insulating strain absorbing member is formed of a glass layer whose coefficient of thermal expansion is between that of the mounting substrate and the electronic component. How to install electronic components described in section. 3. The ultra-thin layer of the insulating strain absorbing member is formed of two glass layers, and the coefficient of thermal expansion of the glass layer on the mounting board side is made close to that of the mounting board, and the coefficient of thermal expansion of the glass layer on the electronic component side is made close to that of the mounting board side. The method of attaching an electronic component according to claim 1, wherein the method is formed close to that of the electronic component.