JPH0638436B2 - Method of joining semiconductor pellet and substrate - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for joining a semiconductor pellet and a substrate.

[Technical background of the invention]

As a method of attaching a semiconductor pellet such as an IC pellet to a substrate, a method of connecting a bump of the semiconductor pellet and a terminal portion of the substrate by wire bonding is generally adopted, but in this method, wire bonding takes time. In addition, since the bonding wire is also expensive, the cost is considerably high. Therefore, recently, a method of directly connecting the bump of the semiconductor pellet to the terminal portion of the substrate has been studied.

As a method for joining a semiconductor pellet and a substrate in which the bumps of the semiconductor pellet are directly connected to the terminal portion of the substrate, a semiconductor pellet and a substrate on which a terminal portion corresponding to each bump of the semiconductor pellet is formed are joined together. A method has been considered in which the semiconductor pellet and the substrate are bonded and bonded with the anisotropic conductive adhesive by interposing an anisotropic conductive adhesive on the surface and relatively pressing.

The anisotropic conductive adhesive is a mixture of electrically conductive particles in an insulating adhesive in such a ratio that the conductive particles do not contact each other, and is made of this anisotropic conductive adhesive. The adhesive layer has conductivity in the thickness direction but has insulation in the surface direction (lateral direction), so that the anisotropic conductive adhesive is interposed between the semiconductor pellet and the substrate to form a semiconductor pellet. When the and the substrate are pressed relative to each other, the bumps of the semiconductor pellet and the terminal portions of the substrate are electrically connected (electrically connected through conductive particles).

[Problems of background technology]

However, in the method of adhesively bonding the semiconductor pellet and the substrate by the anisotropic conductive adhesive as described above, not all the bumps of the semiconductor pellet and each terminal portion of the substrate are necessarily electrically connected, Therefore, it had a problem of poor reliability.

This is because the distribution of the conductive particles of the anisotropic conductive adhesive varies irregularly, whereas the width of each bump of the semiconductor pellet is very narrow, so the anisotropic conductive adhesive There is a place where the spacing of the conductive particles is wider than the width of the bump, and the bump of the semiconductor pellet happens to correspond to this place, and the conductive particle is placed between the bump of this part and the terminal part of the substrate. The bumps and the terminal portions are not electrically connected to each other without the interposition of. Incidentally, if the mixing ratio of the conductive particles in the anisotropic conductive adhesive is increased, the intervals between the conductive particles also become smaller, so that all the bumps and the terminal portions can be almost certainly conductively connected.
When the mixing ratio of the conductive particles in the anisotropic conductive adhesive is increased in this way, the conductive particles come into contact with each other at a portion where the conductive particles are closely spaced to short-circuit adjacent bumps. Will be lost.

Further, the method of adhesively bonding the semiconductor pellet and the substrate with the anisotropic conductive adhesive is a method of applying the anisotropic conductive adhesive to the bonding surface of the semiconductor pellet or the substrate and pressing the semiconductor pellet and the substrate. Since the bumps of the semiconductor pellet and the terminal portion of the substrate can be electrically connected, the semiconductor pellet and the substrate can be joined in a short time, and thus the cost can be reduced to some extent as compared with the method of wire bonding. However, since the anisotropic conductive adhesive is expensive, the cost cannot be drastically reduced.

[Object of the Invention]

The present invention has been made in view of the circumstances as described above, and its purpose is to achieve efficiency in a short time comparable to the method of adhesively bonding a semiconductor pellet and a substrate with an anisotropic conductive adhesive. The semiconductor pellet and the substrate can be bonded well, and the semiconductor pellet and the substrate can be surely conductively connected to each other without causing a defective conduction portion, and the cost is higher than the method using the anisotropic conductive adhesive. It is an object of the present invention to provide a method for joining a semiconductor pellet and a substrate, which can reduce the above-mentioned problem.

[Outline of Invention]

That is, according to the present invention, a semiconductor pellet having a protective film formed on the main surface excluding the terminal portion and a substrate having a terminal portion corresponding to the terminal portion of the semiconductor pellet have both terminal portions facing each other. An insulating adhesive is interposed between the joint surfaces including the parts to relatively press the adhesive, and the pressing force pushes the adhesive between the terminals to the outside between the terminals to electrically connect both terminals. And a bonding method for bonding the semiconductor pellet and the substrate with the adhesive, wherein the terminal portion of the semiconductor pellet is recessed from the upper surface of the protective film, and the terminal portion of the substrate is The semiconductor pellet has a width narrower than that of the terminal portion, and the present invention is an insulating adhesive in which the semiconductor pellet and the substrate are interposed on a joint surface including a portion where both terminal portions of both are opposed to each other. Adhesion Therefore, the semiconductor pellet and the substrate can be efficiently joined in a short time comparable to the method of adhering and joining the semiconductor pellet and the substrate with the anisotropic conductive adhesive, and the semiconductor pellet can also be joined. Since both terminals of the board and the board are directly connected to each other by extruding the insulating adhesive between them, the anisotropic conductive adhesive is used like the method using the anisotropic conductive adhesive. There is no occurrence of defective conduction due to uneven distribution of conductive particles in the adhesive. Further, since the insulating adhesive is considerably cheaper than the anisotropic conductive adhesive, the anisotropic conductive adhesive The cost can be further reduced as compared with the method using.

Example of Invention

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a semiconductor pellet (for example, an IC pellet), and on the main surface of the semiconductor pellet 1, a large number of terminal portions 2, 2, ... Are arranged along the outer periphery thereof. On the main surface of 1, the terminal portion 2,
Insulating protective film 3 is formed over the entire main surface except 2 ,. The semiconductor pellet 1 is, for example, a rectangle having a side length of 4 mm and a thickness of 0.3 mm, and the terminals are arranged at a pitch of 0.1 to 0.5 mm.

Reference numeral 4 is a wiring board made of an insulating material.
A large number of wirings 5, 5, ... Are formed on the surface. The wirings 5, 5, ... Are derived from the semiconductor pellet mounting positions on the surface of the substrate 4, and the ends of the wirings 5, 5 ,. , 2, ... Corresponding semiconductor pellet connecting terminals 5a, 5a ,. The width of the semiconductor pellet connecting terminals 5a, 5a, ... Is made slightly narrower than the width of the terminals 2, 2 ,.

In this embodiment, an insulating adhesive 6 is applied to one of the semiconductor pellet 1 and the substrate 4, for example, at the semiconductor pellet mounting position on the substrate 4 from above the terminal portions 5a, 5a, ... Formed on the surface of the substrate 4. , And the semiconductor pellets 1 are superposed on each other, and the semiconductor pellets 1 and the substrate 4 are relatively pressed, so that the terminal portions 2, 2, ... On the semiconductor pellet 1 side and the terminal portions 5a on the substrate 4 side, Are electrically connected to each other, and the insulating adhesive 6 is cured to bond the semiconductor pellet 1 and the substrate 4 to each other by the insulating adhesive 6. The semiconductor pellet 1 and the substrate 4 are connected to each other. The joining is specifically performed as follows.

First, on the surface of the substrate 1 on which the semiconductor pellet connecting terminal portions 5a, 5a, ... As shown in FIG. 2 (a) are formed, the entire semiconductor pellet bonding surface including the respective terminal portions 5a, 5a ,. The insulating adhesive 6 is applied from above the terminal portions 5a, 5a, ... To a substantially uniform thickness as shown in FIG. 2 (b).

After that, as shown in FIG. 2 (c), the semiconductor pellet 1 is placed on the insulating adhesive 6 and each terminal portion 2,
2, ... Overlap with corresponding terminal portions 5a, 5a, ... on the substrate 4 side, respectively, and in this state, the semiconductor pellet 1 is pressed from above by a pressing jig 7 to separate the semiconductor pellet 1 and the substrate 4 from each other. While pressing relatively, the insulating adhesive 6
Is cured and the semiconductor pellet 1 and the substrate 4 are adhesively bonded to each other with an insulating adhesive 6.

Then, as described above, when the semiconductor pellets 1 are stacked on the insulating adhesive 6 and the semiconductor pellets 1 and the substrate 4 are relatively pressed, the pressing force causes the semiconductor pellets 1 to move.
The adhesive 6 between the terminal portions 2 and 5a of both the substrate 4 and the substrate 4 is extruded to the outside between the terminal portions, and both the terminal portions 2 and 5a come into direct contact with each other as shown in FIG. 2 (c). The lever terminals 2 and 5a are electrically connected. The semiconductor pellet 1
The pressing force for relatively pressing the substrate 4 with the substrate 4 is 700 g to 1
About kg is sufficient, and when the semiconductor pellet 1 and the substrate 4 are relatively pressed with such a pressing force, both terminal portions 2, 5a
The adhesive 6 between the two terminals 2 and 5a
Are connected with sufficient conductivity. Further, when the insulating adhesive 6 is cured in this state, the adhesive 6 bonds the semiconductor pellet 1 and the substrate 4 to each other.

The insulating adhesive 6 may be a room temperature curable type,
A thermoplastic adhesive which is generally called a hot melt type, a thermosetting type adhesive, a UV ink or the like may be used. For example, when a room temperature curing type adhesive is used as the insulating adhesive 6, the substrate 4 surface Immediately after the adhesive is applied to the semiconductor pellets 1, the semiconductor pellets 1 are stacked and pressed, and the adhesive is cured in this state. When the UV ink is used as the insulating adhesive 6, the semiconductor pellet 1 is overlaid on the adhesive applied to the surface of the substrate 4 and finger pressure is applied, and in this state, the ultraviolet irradiation is applied to cure the adhesive. In addition, when a thermoplastic adhesive called hot melt type is used as the insulating adhesive 6, the adhesive is applied to the surface of the substrate 4 and dried, and then the semiconductor pellets are applied. 1 are piled up and heated to the melting temperature of the adhesive (the pressing jig 7 is heated from the semiconductor pellet 1 side as a heating jig also serving as a heating jig, or is heated from the back surface side of the substrate 4 by other means). The adhesive may be pressed and then cooled under pressure to cure the adhesive. When a thermosetting adhesive is used as the insulating adhesive 6, the semiconductor pellets 1 are stacked and pressed immediately after the adhesive is applied, and in this state, they are heated to the curing temperature of the adhesive or the surface of the substrate 4 is covered. It is sufficient to dry (dry at a temperature equal to or lower than the curing temperature) the adhesive applied to the above, and stack the semiconductor pellets 1 on it to heat under pressure to cure the adhesive. In addition,
When a thermosetting adhesive is used as the insulating adhesive 6, it is necessary to select one that cures at a relatively low temperature at which the semiconductor pellet 1 is not destroyed by heat.

After the semiconductor pellet 1 is adhesively bonded to the substrate 4 in this way, the semiconductor pellet 1 is molded with a synthetic resin 8 such as an epoxy resin as required, as shown in FIG.

FIG. 4 shows a semiconductor pellet 1 joined as described above.
2 is an enlarged view of a part of the bonding portion of the substrate 4 and the semiconductor pellet 1 in which the gold bump is removed from the terminal portion 2. In Figure 4, in Figure 4, 11
Is a base material of the semiconductor pellet 1 (here, N-type base material), 12 is a P-type diffusion layer, and 13 is an N-type diffusion layer.
Silicon oxide (SiO 2) is formed on the main surface of the pellet on which 3 is formed.
_An insulating film 14 made of ₂ ) is formed, and a wiring 15 made of aluminum is formed thereon. This wiring 15
In the openings provided in the insulating film 14, the diffusion layers 12, 13
Is electrically connected to a predetermined diffusion layer. The wiring 15 is led to the outer peripheral edge of the pellet.
The end portion of 15 is used as a pad 15a for connecting to an external circuit, and this pad 15a is used as it is for the terminal portion 2 of the semiconductor pellet 1.
It is said that. Further, 3 is an insulating protective film made of silicon oxide formed on the main surface of the semiconductor pellet 1 from above the wiring 15, and the protective film 3 is formed except for the terminal portion 2 made of the pad 15a. There is.

That is, the terminal portion 2 of the semiconductor pellet 1, that is, the connection pad 15a is recessed from the upper surface of the protective film 3 as shown in FIG.

In this embodiment, the reason why the gold bumps are eliminated from the terminal portion 2 of the semiconductor pellet 1 is that the semiconductor pellet 1 is directly bonded to the substrate 4. This is because it is not necessary to provide a gold bump for welding the bonding wire to the semiconductor pellet 1. If the semiconductor pellet 1 has no gold bump from the terminal portion 2 in this way, the semiconductor pellet 1 becomes less expensive. .

Then, in the method of joining the semiconductor pellet and the substrate,
As described above, the insulating adhesive 6 is applied to the surface of the substrate 4, the semiconductor pellet pellets 1 are overlaid thereon, and the semiconductor pellet 1 and the substrate 4 are relatively pressed, so that the semiconductor pellets are pressed by this pressing force. The adhesive 6 between the terminal portions 2 and 5a of the substrate 1 and the substrate 4 is extruded to the outside between the terminal portions 2 and 5a to electrically connect both terminal portions 2 and 5a. Are terminal portions 5a, 5a, ...
It may be solid-painted on the semiconductor pellet bonding surface containing
Further, since the semiconductor pellet 1 and the substrate 4 can be joined only by relatively pressing the semiconductor pellet 1 and the substrate 4 and curing the adhesive 6 in that state, the semiconductor pellet is bonded by the anisotropic conductive adhesive. It is possible to efficiently bond the semiconductor pellet and the substrate in a short time as long as the method of adhesively bonding the substrate and the substrate. Further, in this joining method, since the terminal portions 2 and 5a of both the semiconductor pellet 1 and the substrate 4 are directly connected to each other by extruding the insulating adhesive 6 between them, it is anisotropic. Unlike the method of using a conductive adhesive, conduction due to variations in the distribution of conductive particles in the anisotropic conductive adhesive is not referred to as a defective portion, and the insulating adhesive 6 is anisotropically conductive. Since it is considerably cheaper than the adhesive, the cost can be further reduced as compared with the method using the anisotropic conductive adhesive. In addition, the terminal portion 2 of the semiconductor pellet 1 is connected to the protective film 3
Of the terminal portion 5a of the substrate 4
Since the terminal portion 2 of the semiconductor pellet 1 is made narrower than the terminal portion 2 of the semiconductor pellet 1, the terminal portions 2 and 5a of both the semiconductor pellet 1 and the substrate 4 are directly bonded, so that a bump is formed on the terminal portion 2 of the semiconductor pellet 1. It is cheaper than the method.

In the above embodiment, the insulating adhesive 6 is applied to the entire semiconductor pellet bonding surface of the substrate 4, but the insulating adhesive 6 is applied only to the array portion of the terminal portions 5a, 5a, .... May be.

Further, the insulating adhesive is used for the substrate 4 or the semiconductor pellet 1.
Instead of being applied to the substrate 1, it may be formed into a sheet shape in advance and sandwiched between the substrate 4 and the semiconductor pellet 1.

〔The invention's effect〕

According to the present invention, a semiconductor pellet and a substrate are bonded and joined together with an insulating adhesive which is interposed on a joint surface including portions where both terminal portions face each other. Therefore, the semiconductor pellet is bonded with the anisotropic conductive adhesive. It is possible to efficiently bond the semiconductor pellet and the substrate in a short time comparable to the method of adhesively bonding the substrate and the substrate, and also to use the insulating adhesive between the terminals of both the semiconductor pellet and the substrate. Since the conductive connection is made directly by extruding to the outside, as in the method of using the anisotropic conductive adhesive, the defective conductive part due to the uneven distribution of the conductive particles in the anisotropic conductive adhesive is removed. Moreover, since the insulating adhesive is much easier than the anisotropic conductive adhesive,
The cost can be further reduced as compared with the method using the anisotropic conductive adhesive. Further, the terminal portion of the semiconductor pellet is recessed from the upper surface of the protective film, and the terminal portion of the substrate is narrower than the terminal portion of the semiconductor pellet, so that both the terminal portion of the semiconductor pellet and the terminal portion of the substrate are formed. Is directly bonded, the cost is lower than the method of forming bumps on the terminals of the semiconductor pellet.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention.
FIG. 1 is a schematic view of a joining method, FIG. 2 is a cross-sectional view along a terminal part arrangement line showing a joining process, FIG. 3 is a cross-sectional view of a state in which a semiconductor pellet is molded, and FIG. 4 is A of FIG. It is an expanded sectional view which follows the -A line. 1 ... Semiconductor pellet, 2 ... Terminal part, 15a ... Pad, 3 ... Protective film, 4 ... Substrate, 5 ... Wiring, 5a ...
Terminal, 6 ... Insulating adhesive, 7 ... Pressure jig.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hisashi Masaki Hisashi Masaki 3-2-1, Sakaemachi, Hamura-cho, Nishitama-gun, Tokyo Casio Computer Co., Ltd. Hamura Technical Center (72) Inventor Yoshio Akita Sakae-cho, Hamura-cho, Nishitama-gun, Tokyo 3-2-1, Casio Computer Co., Ltd., Hamura Technology Center (72) Inventor Yoshinori Atsumi 3-2-1, Sakaemachi, Hamura-cho, Nishitama-gun, Tokyo Casio Computer Co., Ltd., Hamura Technology Center (72) Inventor Tamaki Toshiharu 3-2-1 Sakaemachi, Hamura-cho, Nishitama-gun, Tokyo Casio Computer Co., Ltd., Hamura Technical Center (56) Reference JP-A-60-262430 (JP, A)

Claims (1)

[Claims] 1. A semiconductor pellet in which a protective film is formed on the main surface excluding the terminal portion, and a substrate in which the terminal portion corresponding to the terminal portion of the semiconductor pellet is formed, in which both terminal portions face each other. Insulating adhesive is interveningly pressed against the joint surface including, and by this pressing force, the adhesive between the two terminal portions is extruded to the outside between the terminal portions so that the both terminal portions are A method of joining for connecting the semiconductor pellet and the substrate by conducting the conductive connection and curing the adhesive,
Bonding of the semiconductor pellet and the substrate, wherein the terminal portion of the semiconductor pellet is recessed from the upper surface of the protective film, and the terminal portion of the substrate is narrower than the terminal portion of the semiconductor pellet. Method.