JPH0442550A - Method of mounting electronic component - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electronic component mounting method that can be used when mounting electronic components such as chip components and semiconductor elements on an insulating wiring board.

BACKGROUND OF THE INVENTION In recent years, as the electrode pitch of electronic components has become narrower, it has become difficult to connect them by soldering, and mounting methods that do not use solder are being actively researched and developed. Regarding the mounting method of such electronic components, for example, Japanese Patent Application Laid-Open No. 63-2
It is described in No. 50140.

Hereinafter, a conventional electronic component mounting method will be described with reference to the drawings. FIG. 3 is a sectional view showing a conventional electronic component mounting method. In FIG. 3, 1 is an insulating substrate, and 2 is a first electrode formed on the insulating substrate l.

3 is an electronic component, and 4 is a second electrode formed on the surface of the electronic component 3. 5 is a conductive adhesive provided between the first electrode 2 and the second electrode 4. The conductive adhesive 5 is made of a thermosetting adhesive containing a metal filler, the metal filler electrically connects the first electrode 2 and the second electrode 4, and the thermosetting adhesive connects the insulating substrate. 1 and electronic component 3 are mechanically connected.

Problems to be Solved by the Invention However, in the above configuration, the conductive adhesive 5 performs both the electrical connection and the mechanical connection between the insulating substrate 1 and the electronic component 3. It was difficult to optimize the connection resistance value and mechanical connection strength independently. That is, when the content of the metal filler contained in the conductive adhesive 5 is increased in order to lower the connection resistance value, the content of the thermosetting adhesive is decreased, so that the connection resistance between the insulating substrate l and the electronic component 3 is The mechanical connection strength becomes weaker.

Furthermore, when the content of the thermosetting adhesive in the conductive adhesive 5 is increased in order to increase the mechanical connection strength, the content of the metal filler decreases, so that the insulating substrate 1 and the electronic component 3 The problem was that the electrical connection resistance value between them decreased.

In view of the above problems, it is an object of the present invention to provide a method for mounting electronic components that makes it possible to independently optimize electrical connection resistance and mechanical connection strength.

Means for Solving the Problems In order to achieve the above object, the electronic component mounting method of the present invention includes the following steps when mounting an electronic component having a second electrode on an insulating substrate having a first electrode. A conductive resin is provided between the first electrode and the second electrode, and an insulating adhesive is provided between the insulating substrate and the electronic component.

Operation The present invention has the above-described configuration, and provides an electrical connection between the first electrode provided on the insulating substrate and the second electrode provided on the surface of the electronic component. The mechanical connection between the insulating substrate and the electronic component is performed by an insulating adhesive provided between the insulating substrate and the electronic component. This allows the electrical connection resistance value and mechanical connection strength to be optimized independently.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

(Example 1) FIG. 1 is a sectional view showing a method for mounting electronic components in a first example of the present invention. The same numbers are given to the same parts as in the conventional electronic component mounting method shown in FIG.

In FIG. 1, 1 is an insulating substrate, and 2 is an insulating substrate 1.
a first electrode formed above. 3a is a semiconductor element which is an example of an electronic component, and 4 is a second electrode formed on the surface of the semiconductor element 3a.

5a is a conductive resin provided between the first electrode 2 and the second electrode 4, and 6 is an insulating adhesive provided between the insulating substrate 1 and the semiconductor element 38.

In this embodiment, with the above configuration, the electrical connection between the first electrode 2 formed on the insulating substrate 1 and the second electrode 4 formed on the surface of the semiconductor element 3a is made by the conductive resin 5a. By making a mechanical connection between the insulating substrate 1 and the semiconductor element 3a using an insulating adhesive 6, the electrical connection resistance value and the mechanical connection strength are each independently optimized. Resin is selected.

Further, as the insulating adhesive W16, a resin is used which has a large volumetric shrinkage rate during curing and whose thermal expansion coefficient after curing is smaller than that of the conductive resin 5a. Due to the large volumetric shrinkage rate of the insulating adhesive 6 during curing,
The first electrode 2 and the second electrode 4 are electrically connected by being pressed into contact with each other via the conductive resin 5a. Also,
The thermal expansion coefficient of the insulating adhesive 6 after curing is the same as that of the conductive resin 5a.
is smaller than the coefficient of thermal expansion of the insulating adhesive 6, and the area occupied by the insulating adhesive 6 is larger than the area occupied by the conductive resin 5a, so the electrical connection will not be disconnected even when the ambient temperature rises.

In this embodiment, as resins having the above characteristics, a UV curable adhesive was used for the insulating adhesive 6, and an acrylic resin containing a metal filler was used for the conductive resin 5a. By using a UV curing adhesive as the insulating adhesive 6, the mounting process can be performed at room temperature, so even glass substrates that cannot be heated, such as liquid crystal displays, can be used as the insulating substrate 1. can do.

Further, as the insulating adhesive 6, an epoxy adhesive or an acrylic adhesive can also be used. In case 2, the volumetric shrinkage rate during curing is smaller than that of UV curing adhesive, but for example, when curing the adhesive, there is a method of pressing the semiconductor element 3a against the insulating substrate 1 using a pressure tool or the like. By employing a method using a two-component adhesive containing microcapsules encapsulating a curing agent, a predetermined volumetric shrinkage rate upon curing can be obtained.

Furthermore, since the conductive resin 5a is used to electrically connect the first electrode 2 and the second electrode 4, the insulating substrate 1
Alternatively, the undulations and irregularities on the surface of the semiconductor element 3a can be absorbed by the conductive resin 5a, and even the insulating substrate 1 or the semiconductor element 3a with rough surface smoothness can be used.

Next, other embodiments of the present invention will be described with reference to the drawings.

(Example 2) FIG. 2 is a sectional view showing a method for mounting electronic components according to a second example of the present invention. The first aspect of the present invention shown in FIG.
The same numbers are given to the same parts as in the electronic component mounting method according to the embodiment.

In FIG. 2, 1 is an insulating substrate; 2 is an insulating substrate 1;
a first electrode formed above. 3a is a semiconductor element as an electronic component, and 4 is a second electrode formed on the surface of the semiconductor element 3a. 5a is a conductive resin provided between the first electrode 2 and the second electrode 4, and 6 is an insulating adhesive provided between the insulating substrate 1 and the semiconductor element 3a. The configuration is similar. The difference from the configuration shown in FIG. 1 is that a non-oxidizing metal layer 7 is provided on the second electrode 4 of the semiconductor element 3a.

Generally, the second electrode 4 formed on the semiconductor element 3a is made of a metal that is easily oxidized, such as aluminum, but since the aluminum oxide film is non-conductive, the second electrode 4 formed on the semiconductor element 3a is not removed. If the conductive resin 5a is used for connection, the connection resistance value will increase and the variation in the connection resistance value will become large. By removing the oxide film and continuously forming the non-oxidizing metal layer 7, the connection resistance value can be stably reduced even when the connection is made using the conductive resin 5a.

In addition, in the first and second embodiments, the semiconductor element 3a was explained as an example of an electronic component, but as an electronic component,
Any material with electrodes formed on the surface or leads formed for surface mounting may be used. for example,
It is also possible to use so-called SMT components such as chip resistors, chip capacitors, or chip diodes.

In addition, in the second embodiment, the non-oxidized metal layer 7 was provided on the surface of the second electrode 4, but this was provided on the surface of the first electrode 2 or on both the first electrode 2 and the second electrode 4. It may be provided on the surface. In this case, since the non-conductive oxide film on the first electrode 2 can also be removed, it is expected that the connection resistance value will further decrease.

Effects of the Invention As is clear from the above description, the present invention provides a method for mounting an electronic component having a second electrode on an insulating substrate having a first electrode. Since a conductive resin is provided between the first electrode and the second electrode, and an insulating adhesive is provided between the insulating substrate and the electronic component, the electrical connection between the first electrode and the second electrode is By making the connection using the conductive resin and making the mechanical connection between the insulating substrate and the electronic component using the insulating adhesive, the electrical connection resistance value and the mechanical connection strength can be independently adjusted. Can be optimized.

Furthermore, since the insulating adhesive uses a resin whose coefficient of thermal expansion after curing is smaller than that of the conductive resin, the area occupied by the insulating adhesive is larger than that of the conductive resin. Because the area is larger than the area occupied by the wire, the electrical connection will not be disconnected even when the surrounding temperature rises.

Further, by coating one or both of the first electrode and the second electrode with a non-oxidizing metal, the connection resistance value can be stably reduced even when connected with the conductive adhesive. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an electronic component mounting method according to an embodiment of the present invention, FIG. 2 is a sectional view showing an electronic component mounting method according to another embodiment of the invention, and FIG. 3 is a conventional method. FIG. 3 is a cross-sectional view showing a method for mounting electronic components. DESCRIPTION OF SYMBOLS 1... Insulating substrate, 2... First electrode, 3a... Semiconductor element, 4... Second electrode, 5a... ... Conductive resin, 6 ... Insulating adhesive, 7 ... Non-oxidizing metal layer.

Claims (3)

[Claims] (1) When mounting an electronic component having a second electrode on an insulating substrate having a first electrode, a conductive resin is provided between the first electrode and the second electrode, and . A method for mounting an electronic component, comprising providing an insulating adhesive between the insulating substrate and the electronic component. (2) The electronic component mounting method according to claim 1, wherein one or both of the first electrode and the second electrode is coated with a non-oxidizing metal. (3) The electronic component mounting method according to claim 1 or 2, wherein the thermal expansion coefficient of the insulating adhesive after curing is smaller than that of the conductive resin.