JPH09266227A - Bonding method of electronic parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict bad bonding at electronic parts by intervening a conductive anaerobic bonding agent between a bump and a circuit pattern, and hardening the conductive anaerobic bonding agent. SOLUTION: A copper bump 6 is protruded on the lower surface of electronic parts 8, and a circuit pattern 12 of a substrate 11 also comprises copper. Herein, the bump 9 is directed downward, and a conductive anaerobic bonding agent 11 is applied on a lower part of the bump 9. As the conductive anaerobic bonding agent there is used one where a catalyst such as organic peroxide, a stabilizer such as qunone, and charged particles of noble metal including silver or silver palladium are added to a main agent such as urethaneacrylate, for example. A ceramics substrate unlikely to thermally deform is preferable as the substrate 11. The electronic parts 8 are pressed downward, and the conductive anaerobic bonding agent 10 applied on the lower part of the bump 9 is pressed against the circuit pattern, and hardened in the state where air is interrupted nearer to come into the conductive anaerobic bonding agent 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining electronic components, in which bumps provided on the electronic components are joined to a circuit pattern on a substrate using an adhesive.

[0002]

2. Description of the Related Art In recent years, some electronic components have bumps made of metal on their lower surfaces, and a method of bonding the bumps of this electronic component to a circuit pattern on a substrate by using a conductive adhesive is put into practical use. Has come to change.

Next, a conventional method for joining electronic components will be described with reference to FIG. In FIG. 2A, 1
Is a substrate made of glass epoxy or ceramics,
Circuit patterns 2 and 3 are formed on the surface of the substrate 1, and an adhesive 4 is applied to these circuit patterns 2 and 3. Reference numeral 5 is an electronic component mainly composed of a semiconductor chip, and a plurality of bumps 6 and 7 are projectingly provided on the lower surface thereof.

In the conventional method of joining electronic parts,
As shown in FIG. 2B, the bumps 6 and 7 are brought into contact with the adhesive 4 and heated to 150 ° C. or higher to cure the adhesive 4. As a result, the bumps 6 and 7 are fixed to the circuit patterns 2 and 3, and the both are electrically connected.

[0005]

However, in the conventional method of joining electronic components, a thermosetting adhesive containing silver or silver or palladium is used as the adhesive 4, and the curing temperature of the adhesive 4 is It is considerably higher than room temperature, such as above 150 ° C. Further, there is a large difference in linear expansion coefficient between the substrate 1 and the electronic component 5. Of course, the substrate 1 is much more susceptible to thermal deformation than the electronic component 5.

Therefore, as shown in FIG. 2B, when the adhesive 4 is hardened and hardened and then returned to room temperature, the electronic component 5 is hardly deformed, but the substrate 1 is considerably deformed and warped. Will end up. Therefore, as shown in FIG.
As shown in FIG. 2D in which the portion A of FIG. 2C is enlarged, the adhesive 4 is formed near the interface between the cured adhesive 4 and the circuit pattern 2 at the joint between the substrate 1 and the electronic component 5. There was a case where it was broken and a defective joint was generated.

[0007] Therefore, an object of the present invention is to provide a method for joining electronic components, which can suppress joining defects.

[0008]

A method for joining electronic components according to the present invention is a method for joining electronic components in which bumps formed on the lower surface of the electronic component are joined to a circuit pattern on a substrate. The conductive anaerobic adhesive is interposed between the two to cure the conductive anaerobic adhesive.

[0009]

According to a first aspect of the present invention, there is provided a method of joining an electronic component, wherein a bump formed on a lower surface of the electronic component is joined to a circuit pattern of a substrate, which is a conductive anaerobic bond between the bump and the circuit pattern. Since the conductive anaerobic adhesive is to be cured with the agent interposed, it is possible to perform the bonding with the adhesive at a lower temperature than the conventional technology, and to reduce the fracture phenomenon of the adhesive due to the temperature difference. You can

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a process explanatory diagram of a method for joining electronic components according to an embodiment of the present invention. In this embodiment, bumps 9 made of copper are provided on the lower surface of the electronic component 8, and the circuit pattern 12 of the substrate 11 is also made of copper, as shown in FIG.

First, as shown in FIG.
With the conductive anaerobic adhesive 1 on the bottom of the bump 9.
Apply 0. As the conductive anaerobic adhesive 10, for example, one having the components shown in the following table is suitable.

[0012]

[Table 1]

The curing temperature of the conductive anaerobic adhesive 10 is
Substrate 1 when a glass epoxy substrate is used as the substrate 11
Below the glass transition temperature of 1 (about 120 ° C). Further, when a ceramics substrate is used as the substrate 11, the ceramics substrate is less likely to be thermally deformed than the glass epoxy substrate, and thus is more preferable. That is, as the substrate 11 of the present invention, either a glass epoxy substrate or a ceramic substrate may be used.

Then, as shown in FIG. 1C, an arrow N
As indicated by 1, the electronic component 8 is pressed downward to press the conductive anaerobic adhesive 10 applied on the lower portion of the bump 9 against the circuit pattern 12. As a result, the air is blocked, and the inside of the conductive anaerobic adhesive 10 does not come into contact with air, and the curing starts.

Here, in the state of FIG. 1C, the conductive anaerobic adhesive 10 may be cured at room temperature. Even in this case, the circuit pattern 12 and the bumps 9 are made of copper, and the ions generated from copper act as a catalyst for promoting the curing of the conductive anaerobic adhesive 10. Examples of such a metal include nickel and aluminum in addition to copper, and a metal such as nickel may be used.

Further, in order to accelerate the curing of the conductive anaerobic adhesive 10, the temperature is heated to room temperature or higher and the glass transition temperature (about 120 ° C.) or lower of the substrate 11. When the conductive anaerobic adhesive 10 described above is used, it is not necessary to heat to a high temperature that does not exceed the glass transition temperature, unlike the conventional method for joining electronic components. Therefore, even if the temperature is returned to room temperature, the substrate 11 does not largely warp, and the breakage of the adhesive can be prevented.

[0017]

The method for joining electronic components of the present invention is a method for joining electronic components in which bumps formed on the lower surface of the electronic component are joined to the circuit pattern of the substrate, and the bumps and the circuit pattern are electrically conductive. Since the conductive anaerobic adhesive is cured by interposing the anaerobic anaerobic adhesive, it is possible to perform the bonding at a low temperature at which the thermal deformation of the substrate does not pose a problem, and it is possible to suppress the bonding failure.

[Brief description of drawings]

FIG. 1A is a process explanatory diagram of a method for joining electronic components according to an embodiment of the present invention. FIG. 1B is a process explanatory diagram of a method for joining electronic components according to an embodiment of the present invention. Process explanatory drawing of the joining method of the electronic component in one Embodiment

FIG. 2A is a process explanatory view of a conventional electronic component joining method. FIG. 2B is a process explanatory diagram of a conventional electronic component joining method. Of process steps for joining electronic components

[Explanation of symbols]

 8 Electronic Components 9 Bumps 10 Conductive Anaerobic Adhesive 11 Substrate 12 Circuit Pattern

Claims (4)

[Claims] 1. A method of joining an electronic component, wherein a bump formed on a lower surface of the electronic component is joined to a circuit pattern of a substrate, wherein a conductive anaerobic adhesive is interposed between the bump and the circuit pattern. A method for joining electronic components, characterized in that the conductive anaerobic adhesive is cured. 2. The curing is performed at room temperature or above and below the glass transition temperature of the substrate.
A method for joining electronic components as described. 3. The method for joining electronic components according to claim 1, wherein the substrate is an organic substrate, and a curing temperature of the conductive anaerobic adhesive is lower than a glass transition temperature of the substrate. 4. The method for joining electronic components according to claim 1, wherein the bumps and the circuit patterns are made of a metal serving as a catalyst for promoting the curing of the conductive anaerobic adhesive.