JPH09219579A - Connecting method and device of electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability upon the connecting status in the case of connecting an electronic part with an electrode through the intermediary of a thermosetting conductive adhesive. SOLUTION: An ACF 13 in the size required for connection is fed to a semiconductor chip 12. At this time, a void 14 is formed around a protrusion of the semiconductor chip 12 moreover, irregularities 13a are formed on the surface of the fed ACF 13. Next, a chip electrode 12a and a substrate electrode 15a are opposed to each other. The semiconductor chip 12 in the state of pressure welded onto a circuit substrate 15 is heated. In the first heating step, the semiconductor chip 12 is heated at the temperature between the sofening start temperature and setting start temperature to thermal-expand the air inside the void 14 to making the floating easier to exhaust the air out of the cormecting part. In the second heating step, a cormecting device tool 11 is set up at the setting temperature of the ACF 13 for setting said ACF 13 thereby enabling the ACF 13 to be fixed in the state of leaving no void at all around the chip electrode 12a and the substrate electrode 15a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component connecting method and a connecting device for connecting an electronic component having an electrode such as a circuit board or a semiconductor chip by using an anisotropic conductive adhesive. is there.

[0002]

2. Description of the Related Art Conventionally, techniques in such a field include:
For example, some documents were described in the following documents. Literature; The 5th Microelectronics Symposium (M
ES'93) Proceedings Naoyuki Shiozawa, Kazuhiro Isaka, Isao Tsukagoshi, Kyohisa Ohta, "Role of conductive particles in high-density connection using anisotropic conductive film", P.79-82 Figure 2 (a), ( FIG. 2B is a process diagram showing an example of a conventional method for connecting electronic components (for example, a circuit board and a semiconductor chip) described in the above document. Hereinafter, the process (1),
(2) will be described with reference to FIGS. 2 (a) and 2 (b).

(1) Process of FIG. 2 (a) The substrate electrode 1a formed on the surface of the circuit board 1 and the chip electrode 2a formed on the surface of the semiconductor chip 2 are opposed to each other, and anisotropic conductivity is provided therebetween. Anisotropic adhesive film (Anisotropic Conductive Film, hereinafter ACF)
Say) 3. The ACF 3 uses, as the conductive particles 3a, metal particles such as solder or deformable conductive particles obtained by plating metal such as gold (Au) on plastic particles, which is used as a thermosetting epoxy resin. It is uniformly dispersed. (2) Using the connection device of FIG. 2B, the temperature at which the resin of the ACF 3 is cured with respect to the ACF 3 via the semiconductor chip 2 (for example, 200
Heating (H) and pressurization (P) (for example, 4 kg / 5 mm ² ) at (° C.) to attach the substrate electrode 1a and the chip electrode 2a to the conductive particles 3a.
Connect through. In the method of connecting the circuit board 1 and the semiconductor chip 2 using the ACF 3, the connection resistance between the board electrode 1a and the chip electrode 2a can be lowered, and the circuit board 1 has a plurality of board electrodes 1a with fine intervals. Alternatively, even when the semiconductor chip 2 has a plurality of chip electrodes 2a with fine intervals, connection is possible.

[0004]

However, the electronic component connecting method of FIG. 2 has the following problems. That is, in FIG. 2, the substrate electrode 1a and the chip electrode 2a are AC
Due to the unevenness of the ACF 3 formed when the F 3 is supplied, the ACF 3 may be connected in a state in which air is entrained (that is, a void is generated). Therefore, the adhesive strength or the reliability of the connected state may be reduced. Further, when the circuit board 1 has a plurality of finely spaced substrate electrodes 1a, or when the semiconductor chip 2 has a plurality of finely spaced chip electrodes 2a, the voids expand due to heat during bonding, There is a problem that the expansion causes the ACF 3 to flow out more than necessary around the connecting portion between the substrate electrode 1a and the chip electrode 2a, and the reliability of the connection state between the substrate electrode 1a and the chip electrode 2a is deteriorated. .

[0005]

In order to solve the above-mentioned problems, the first invention uses a thermosetting anisotropic conductive adhesive for the electrodes of the first electronic component to form a second electronic component. In the method of connecting the electronic component connected to the electrode, the following steps are performed. That is, the step of aligning the electrodes of the first electronic component and the electrodes of the second electronic component to face each other, and the first electronic component to which the anisotropic conductive adhesive is applied is the second electronic component. A first heating step of heating the anisotropic conductive adhesive at a temperature between a softening start temperature and a curing start temperature of the anisotropic conductive adhesive for a predetermined time while being pressed against the electronic component; A second heating step of heating the anisotropically conductive adhesive at a temperature at which the anisotropically conductive adhesive cures for a predetermined time is sequentially performed. According to the first aspect of the invention, since the electronic component connecting method is configured as described above,
In the alignment process, the electrodes of the first electronic component and the second
The position is set so as to face the electrode of the electronic component.

Next, in the first heating step, the anisotropic conductive adhesive is applied in a state in which the first electronic component coated with the anisotropic conductive adhesive is pressed against the second electronic component. The agent is heated at a temperature between the softening start temperature and the curing start temperature of the anisotropically conductive adhesive for a predetermined time. Then, the anisotropic conductive adhesive is softened, the air in the voids formed around the bumps and the like on the surface of the first electronic component expands, and this air causes the electrode of the first electronic component to expand. And is discharged to the outside of the connection portion between the second electronic component and the electrode. Furthermore, in the second heating step, the anisotropic conductive adhesive between the first electronic component and the second electronic component is heated for a predetermined time at a temperature at which the anisotropic conductive adhesive cures. , The electrode of the first electronic component and the electrode of the second electronic component are connected to each other in a state where no void remains at their connecting portions.

According to a second aspect of the invention, in an electronic component connecting device for connecting an electrode of a first electronic component to an electrode of a second electronic component via a thermosetting anisotropic conductive adhesive, Equipped with various means. That is, the alignment means that makes the electrodes of the first electronic component and the electrodes of the second electronic component face each other, and the first electronic component to which the anisotropic conductive adhesive is applied is the second electronic component. After heating the anisotropic conductive adhesive in a state of being pressed against the electronic component at a temperature between the softening start temperature and the curing start temperature of the anisotropic conductive adhesive for a predetermined time, the anisotropic conductive adhesive And heating means for heating the anisotropic conductive adhesive for a predetermined time at a temperature at which the anisotropic conductive adhesive is cured.

According to the second aspect of the invention, the position of the electrode of the first electronic component is adjusted by the alignment means so as to face the electrode of the second electronic component. Next, the first
The anisotropic conductive adhesive applied to the electronic component is heated from the softening start temperature to the curing start temperature of the anisotropic conductive adhesive while being pressed against the second electronic component with a predetermined pressure by the heating means. It is heated for a predetermined time at a temperature between. Then, the anisotropic conductive adhesive is softened, and the air in the voids formed around the bump (projection) or the like on the surface of the first electronic component expands, and this air expands. Is discharged to the outside of the connecting portion between the electrode of the electronic component and the electrode of the second electronic component. Thereafter, the anisotropic conductive adhesive is heated for a predetermined time at a temperature at which the anisotropic conductive adhesive is cured, and the electrodes of the first electronic component and the electrodes of the second electronic component are separated from each other. The connection is made without leaving any voids.
Therefore, the above problem can be solved.

[0009]

1 (a) to 1 (d) are process drawings showing an example of a method of connecting electronic components showing an embodiment of the present invention. Hereinafter, the steps (1) to (4) will be described with reference to FIGS.
This will be described with reference to (d). (1) Process of FIG. 1 (a) After the first electronic component (for example, semiconductor chip) 12 having the chip electrode 12a is vacuum-sucked to the connection device 11,
Heat (eg, 50 to 60 ° C.) and load (eg, 700) for softening and separating the ACF 13 from the connection device 11
Approximately 1000 g / 5 mm ² ) is applied for a predetermined time (for example, 2 seconds). Then, the sheet-shaped or tape-shaped ACF 13 supplies the semiconductor chip 12 with the ACF 13 having a size necessary for connection. At this time, voids 14 due to the entrained air are formed around the bumps such as the chip electrodes 12a of the semiconductor chip 12, and further, the unevenness 13a is formed on the surface of the supplied ACF 13.

(2) Process of FIG. 1B (positioning process) The semiconductor chip 12 supplied with the ACF 13 is connected to the connecting device 1
Substrate electrode 15 formed on the surface of the chip electrode 12a and the second electronic component (for example, a circuit board) 15 by being attracted to
Face a. In addition, in this alignment step, the connection device 11 functions as alignment means. That is,
The connection device is arranged such that the image recognition pattern on the semiconductor chip 12 and the image recognition pattern on the circuit board 15 are recognized by a CCD camera or the like, the parallelism between them is obtained, and the chip electrode 12a and the substrate electrode 15a face each other. Adjust the position of 11.

(3) Step of FIG. 1C (first heating step) The semiconductor chip 12 is mounted on the circuit board 15 by using the connecting device 11 which is a heating means for adsorbing the aligned semiconductor chip 12. Heat with pressure contact. As a first step, this heating makes the voids 14 due to the entrained air thermally expand and flow easily, so that the temperature between the softening start temperature (50 to 60 ° C) and the hardening start temperature (about 200 ° C) of the ACF 13 is increased. (For example, the temperature is lower than the curing start temperature by about 20 to 30 ° C.) and held for about 10 seconds, and the air in the void 14 is discharged to the outside of the connection portion. (4) Process of FIG. 1D (second heating process) As the second stage heating, the temperature of the connection device 11 is set to ACF1.
Set the temperature at which the resin of 3 cures (for example, 200 ℃),
Hold for about 30 seconds to cure the resin of the ACF 13,
Fix with no voids remaining at the connection. afterwards,
The adsorption ends and the connection ends.

By carrying out the above steps (1) to (4) in order, the voids remaining around the bumps or other steps in the connecting portion are reduced. By reducing this void, ACF
Since the resin of No. 13 does not harden in the state of being extruded to the outside of the connecting portion, the amount of protrusion of the ACF 13 is reduced. As described above, in the present embodiment, first, in the first heating step, the resin in the ACF 13 is softened by holding it at a temperature lower than the curing start temperature of the resin in the ACF 13 for an appropriate time, and the air in the void 14 is removed. By expanding, air is discharged to the outside of the connection part. Next, in the second heating step, the resin of the ACF 13 is heated at a temperature at which the resin is cured to completely cure the resin and fix the connection portion between the chip electrode 12a and the substrate electrode 15a. By these two steps of heating, voids remaining around the steps of the chip electrode 12a, the substrate electrode 15a, etc. are reduced, so that the resin is pushed out of the connection portion between the chip electrode 12a and the substrate electrode 15a. The amount of protrusion of the ACF 13 can be reduced without curing. Therefore, ACF13
The reliability of the connection state between the semiconductor chip 12 and the circuit board 15 via the is improved.

The present invention is not limited to the above embodiment,
Various modifications are possible. For example, there are the following modifications. (A) In the process of FIG.
When the ACF 13 is attached to the substrate, the semiconductor chip 12 may be faced up and the ACF 13 may be faced downward to drop the ACF 13. (B) In the process of FIG. 1B, the chip electrode 12a
The position of the substrate electrode 15a is adjusted.
The position of may be adjusted. (C) In the above embodiment, the case where the semiconductor chip 12 and the circuit board 15 are connected has been described, but the present invention can also be applied to connection between a semiconductor chip and a semiconductor chip, connection between a circuit board and a circuit board, and the like.

[0014]

As described in detail above, according to the first aspect of the present invention, first, in the first heating step, the first electronic component coated with the anisotropic conductive adhesive is replaced with the second electronic component. The anisotropic conductive adhesive is softened by holding it at a temperature between the softening start temperature and the curing start temperature of the anisotropic conductive adhesive for a suitable time in a state of being pressed against the part, and thereby the first electronic component. By expanding the air in the void formed around the step such as the bump on the surface of the air, the air is moved to the outside of the connecting portion between the electrode of the first electronic component and the electrode of the second electronic component. Discharge. Next, in the second heating step, the anisotropic conductive adhesive is heated at a temperature at which it cures to completely cure the anisotropic conductive adhesive and fix the connection portion. By these two steps of heating, voids remaining around the steps such as the bumps are reduced, so that the anisotropic conductive adhesive connects the electrode of the first electronic component and the electrode of the second electronic component. It is possible to reduce the amount of protrusion of the anisotropic conductive adhesive without being cured while being pushed out of the portion. Therefore, it is possible to improve the reliability of the connection state between the first electronic component and the second electronic component via the anisotropic conductive adhesive.

According to the second aspect of the invention, in the electronic component connecting device, the alignment means for facing the electrode of the first electronic component and the electrode of the second electronic component and the anisotropic conductive adhesive are covered. The anisotropic conductive adhesive is fixed at a temperature between the softening start temperature and the curing start temperature of the anisotropic conductive adhesive in a state where the attached first electronic component is pressed against the second electronic component. Heating means for heating the anisotropically conductive adhesive for a predetermined time at a temperature at which the anisotropically conductive adhesive cures. The electrodes of the second electronic component are connected to each other in the state where no void remains at their connecting portions. Therefore, the anisotropic conductive adhesive does not cure while being pushed out of the connection portion between the electrode of the first electronic component and the electrode of the second electronic component, and the anisotropic conductive adhesive The protruding amount of the agent can be reduced, and the reliability of the connection state between the electrode of the first electronic component and the electrode of the second electronic component via the anisotropic conductive adhesive can be improved.

[Brief description of drawings]

FIG. 1 is a process drawing of an electronic component connecting method according to an embodiment of the present invention.

FIG. 2 is a process diagram of a conventional method for connecting electronic components.

[Explanation of symbols]

1,15 Circuit board (electronic component) 1a, 2a, 12a, 15a Electrode 2,12 Semiconductor chip (electronic component) 3,13 Anisotropic conductive film (anisotropic conductive adhesive) 11 Tool (heating means)

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Yuko Kitayama 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (2)

[Claims] 1. A method of connecting an electronic component, wherein the electrode of the first electronic component is connected to the electrode of the second electronic component by using a thermosetting anisotropic conductive adhesive, comprising: A step of aligning an electrode and an electrode of the second electronic component so as to face each other; and the first electronic component to which the anisotropic conductive adhesive is adhered is pressed against the second electronic component. A first heating step of heating the anisotropic conductive adhesive at a temperature between a softening start temperature and a curing start temperature of the anisotropic conductive adhesive for a predetermined time; And a second heating step of heating at a temperature at which the conductive adhesive is cured for a predetermined time, in order. 2. An electronic component connecting device for connecting an electrode of a first electronic component to an electrode of a second electronic component via a thermosetting anisotropic conductive adhesive, comprising: Positioning means for facing an electrode and an electrode of the second electronic component to each other, and the first electronic component to which the anisotropic conductive adhesive is applied, in a state of being pressed against the second electronic component. After heating the anisotropic conductive adhesive at a temperature between the softening start temperature and the curing start temperature of the anisotropic conductive adhesive for a predetermined time, the anisotropic conductive adhesive is converted into the anisotropic conductive adhesive. A connecting device for electronic parts, comprising: a heating means for heating at a curing temperature for a predetermined time.