JPH0563027A - Bonding method for semiconductor device and substrate - Google Patents

Abstract

PURPOSE:To provide a junction method between a semiconductor device and a substrate which is capable of reducing production cost by a further extent compared with an anisotropic conductive bonding agent-based method and, what is more, applicable to substrates having lower heat resistant properties. CONSTITUTION:An ultraviolet setting type insulating bonding agent 6 is applied to one side of a semiconductor device 1 at a thick coat in such a fashion that bumps 2b may be buried therein while each connection terminal 5a of a substrate 4 is formed in smaller width compared with the bumps 2b. Each bump 2b of the semiconductor device 1 is aligned with each mating connection terminal 5a of the substrate 4 so that the semiconductor device 1 and the substrate 4 are relatively depressed. Under this condition, ultraviolet rays are emitted thereto so that the insulating bonding agent 6 may be set.

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 a semiconductor device and a substrate.

[0002]

2. Description of the Related Art As a method of mounting a semiconductor device such as an IC device on a substrate, a method of connecting a bump of a semiconductor pellet and a terminal portion of the substrate by wire bonding is generally used. Not only is the bonding time consuming, but the cost of the bonding wires is also very high, so these days,
A method of directly connecting the bumps of the semiconductor pellet to the terminal portions of the substrate has been studied.

Conventionally, as a method of joining a semiconductor device and a substrate in which bumps of the semiconductor device are directly connected to terminal portions of the substrate,
The semiconductor device and the substrate are formed by relatively pressing the semiconductor device and the substrate on which the terminal portions corresponding to the bumps of the semiconductor device are formed with the anisotropic conductive adhesive interposed between the semiconductor device and the substrate. A method of adhesively bonding the above with the anisotropic conductive adhesive is considered.

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. Since the adhesive layer made of an agent has conductivity in the thickness direction but has an insulating property in the surface direction (lateral direction), an anisotropic conductive adhesive is interposed on the bonding surface between the semiconductor pellet and the substrate. When the semiconductor pellet and the substrate are pressed relative to each other,
Each bump of the semiconductor pellet and each terminal portion of the substrate are electrically connected (electrically connected via conductive particles).

[0005]

However, in the method of adhesively bonding the semiconductor device and the substrate with the anisotropic conductive adhesive as described above, all of the bumps of the semiconductor device and the terminal portions of the substrate are all indispensable. There is a problem in that reliability is poor because it is not always connected electrically. 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 device is very narrow, so that the anisotropic conductive adhesive There is a portion where the distance between the conductive particles is wider than the width of the bump, and the bump of the semiconductor device happens to correspond to this portion, the conductive particle is present between the bump at this portion and the terminal portion of the substrate. The bump and the terminal portion are not electrically connected to each other without the interposition of.

If the mixing ratio of the conductive particles in the anisotropic conductive adhesive is increased, the distance between the conductive particles also becomes smaller, so that all the bumps and the terminal portions can be almost surely electrically connected. However, if the mixing ratio of the conductive particles in the anisotropic conductive adhesive is increased in this way, the conductive particles will come into contact with each other at the portion where the conductive particles are closely spaced and the adjacent bumps will be adjacent to each other. Will be short-circuited.

In the method of adhesively bonding the semiconductor device and the substrate with the anisotropic conductive adhesive, the anisotropic conductive adhesive is applied to the bonding surface of the semiconductor device or the substrate, and the semiconductor device and the substrate are pressed. By doing so, the bumps of the semiconductor device and the terminal portions of the substrate can be electrically connected, so that the semiconductor device 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 by wire bonding. However, the cost was not significantly reduced because the anisotropic conductive adhesive was expensive.

Further, in the above-mentioned joining using the anisotropic conductive adhesive, it is not preferable to maintain the pressure state for a long time until the adhesive is hardened. Therefore, a hot melt type adhesive is generally used. There is also a problem that such a joining method cannot be applied to a substrate having low heat resistance.

The present invention has been made in view of the above circumstances, and its purpose is to efficiently perform a semiconductor device as in the method of adhesively bonding a semiconductor device and a substrate with an anisotropic conductive adhesive. And a substrate can be bonded together, the cost can be further reduced as compared with the method using an anisotropic conductive adhesive, and the semiconductor can be applied to a substrate having lower heat resistance. It is to provide a method of joining a device and a substrate.

[0010]

According to a method of joining a semiconductor device and a substrate of the present invention, an ultraviolet curable insulating adhesive is thickly deposited so that a bump is buried on one surface of the semiconductor device, and each connection of the substrate is made. Forming a terminal portion for use narrower than the bump, aligning each bump of the semiconductor device with each corresponding connecting terminal portion of the substrate, and relatively pressing the semiconductor device and the substrate, In this state, ultraviolet rays are irradiated to cure the insulating adhesive.

[0011]

According to such a joining method, since the joining is performed only by the insulating adhesive and expensive conductive particles are not used at all, the material is inexpensive, and the insulating adhesive is applied to the entire surface of the semiconductor device. Since it only needs to be attached, it is very efficient and the cost can be reduced. Further, since the insulating adhesive is an ultraviolet curable type which is cured by irradiation of ultraviolet rays, low temperature bonding is possible, and a substrate having low heat resistance can be used and bonding reliability can be improved. Further, since the connection terminals of the substrate are narrower than the bumps of the semiconductor device, the tolerance of positional deviation can be increased, and the production efficiency is further improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a semiconductor device (for example, I
C pellets), on the main surface of the semiconductor device 1, a large number of terminal portions 2, 2, ...
Further, on the main surface of the semiconductor device 1, the terminal portions 2, 2,
Except for ..., Insulating protective film 3 is formed over the entire main surface. The semiconductor device 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.

A wiring board 4 made of an insulating material has a large number of wirings 5, 5, ... Formed on the surface of the board 4. The wirings 5, 5, ... Are derived from the semiconductor device mounting position on the surface of the substrate 4, and the ends of the wirings 5, 5 ,.
, And semiconductor device connecting terminal portions 5a, 5a, ... Corresponding to the respective terminal portions 2, 2 ,. The width of the semiconductor device connecting terminal portions 5a, 5a, ... Is made slightly narrower than the width of the terminal portions 2, 2 ,.

In this embodiment, one of the semiconductor device 1 and the substrate 4, for example, at the semiconductor device mounting position of the substrate 4, the insulating adhesive 6 is applied from above the terminal portions 5a, 5a, ... Formed on the surface of the substrate 4. Are applied, the semiconductor device 1 is overlaid thereon, and the semiconductor device 1 and the substrate 4 are pressed relatively to each other, so that each terminal portion 2, 2, ... On the semiconductor device 1 side and each terminal on the substrate 4 side are applied. While electrically connecting the parts 5a, 5a, ...
The semiconductor device 1 and the substrate 4 are obtained by curing the insulating adhesive 6.
And are bonded together with an insulating adhesive 6,
The joining of the semiconductor device 1 and the substrate 4 is specifically performed as follows.

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

Thereafter, as shown in FIG. 2C, the semiconductor device 1 is mounted on the insulating adhesive 6 so that the terminal portions 2, 2, ... Are connected to the terminal portions 5a, 5a on the substrate 4 side. , And so on, and in this state, the semiconductor device 1 is pressed from above by a pressing jig 7 to relatively press the semiconductor device 1 and the substrate, and the insulating adhesive 6 is cured. Then, the semiconductor device 1 and the substrate 4 are adhesively bonded to each other with the insulating adhesive 6.

When the semiconductor device 1 is overlaid on the insulating adhesive 6 and the semiconductor device 1 and the substrate 4 are relatively pressed as described above, the pressing force causes the semiconductor device 1 to move.
The adhesive 6 between the terminal portions 2 and 5a of 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 two terminal portions 2, 5a are electrically connected. The pressing force for relatively pressing the semiconductor device 1 and the substrate 4 is about 700 g to 1 Kg, and when the semiconductor device 1 and the substrate 4 are relatively pressed by this pressing force, both terminal portions are pressed. The adhesive 6 between the terminals 2 and 5a is almost completely extruded and the two terminal portions 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 device 1 and the substrate 4 to each other.

As the adhesive, a thermoplastic adhesive or a thermosetting adhesive which is generally called a room temperature curable type or a hot melt type may be considered. In the present invention, the insulating adhesive 6 is used. It is characterized by using UV ink. In this case, the semiconductor device 1 is superposed on the UV ink insulating adhesive 6 applied to the surface of the substrate 4 and pressed, and in this state, the insulating adhesive 6 is cured by irradiating ultraviolet rays. In this bonding method, the bonding is performed at a lower temperature than the thermocompression bonding method of directly heating, so that the substrate 4 can be made of an inexpensive material having low heat resistance. After the semiconductor device 1 is adhesively bonded to the substrate 4 in this manner, the semiconductor device 1 is molded with a synthetic resin 8 such as an epoxy resin as required, as shown in FIG.

FIG. 4 is an enlarged view of a part of the joint portion between the semiconductor device 1 and the substrate 4 joined as described above. The semiconductor device 1 has the terminal portion 2 without the gold bump. It is said that. That is, in FIG.
Is a base material of the semiconductor device 1 (here, N-type base material), 12 is P
Type diffusion layer, 13 is an N type diffusion layer, and these diffusion layers 1
Silicon oxide (Si
An insulating film 14 made of O ₂ ) is formed, and a wiring 15 made of aluminum is formed thereon. The wiring 15 is electrically connected to a predetermined diffusion layer of the diffusion layers 12 and 13 at the opening provided in the insulating film 14. Further, the wiring 15 is led out to the outer peripheral portion of the one surface of the device, and the end portion of the wiring 15 is used as a pad 2a for connection with an external circuit, and the pad 2a is directly the terminal portion of the semiconductor device 1. It is supposed to be 2. Further, 3 is an insulating protective film made of silicon oxide formed on the main surface of the semiconductor device 1 from above the wiring 15, and the protective film 3 is formed excluding the terminal portion 2 made of the pad 2a. There is.

FIG. 5 is a sectional view taken along the arrangement of the terminal portions of the semiconductor device 1 and the substrate 4 for explaining the most preferred embodiment of the joining method of the present invention. Here, gold is plated on each pad 2a (see FIG. 4) of the terminal portions 2, 2, ... Of the semiconductor device 1 to form gold bumps 2b, 2b ,. Further, as shown in FIG. 5, the one surface of the semiconductor device 1 on which the gold bumps 2b, 2b, ...
The ink insulating adhesive 6 is applied thickly so that the gold bumps 2b, 2b, ... Are buried. In this case, the coated surface of the insulating adhesive 6 does not extend beyond the area of the semiconductor device 1, so that the coated amount can be easily controlled. The insulating adhesive may be formed into a sheet shape in advance.

[0022]

As described above, in the joining method of the present invention, the material is inexpensive because the joining is performed only by the insulating adhesive and no expensive conductive particles are used.
Moreover, since the insulating adhesive only needs to be applied to the entire surface of the semiconductor device, it is very efficient and the cost can be reduced. Further, the insulating adhesive is an ultraviolet curable type which is cured by irradiation of ultraviolet rays. Therefore, low-temperature bonding is possible, a substrate with low heat resistance can be used, bonding reliability can be improved, and the connection terminals of the substrate are narrower than the bumps of the semiconductor device. Therefore, there is an effect that the tolerance of the positional deviation can be increased and the production efficiency can be further improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a joining method for explaining the joining method of the present invention.

FIG. 2 is a cross-sectional view taken along an arrangement of terminal portions for explaining a coated state of an insulating adhesive.

FIG. 3 is a cross-sectional view of a state in which a semiconductor device is molded.

FIG. 4 is an enlarged cross-sectional view taken along the line AA of FIG.

FIG. 5 is a cross-sectional view showing a most preferred embodiment of the joining method of the present invention along a semiconductor device and a substrate terminal portion arrangement line.

[Explanation of symbols]

1 ... Semiconductor device (IC pellet), 2 ... Terminal part, 2a ...
Pads, 2b ... Gold bumps, 4 ... Substrate, 5 ... Wiring, 5a ...
Terminal part, 6 ... Insulating adhesive (UV ink)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisashi Masaki 3-2-1 Sakaemachi, Hamura-shi, Tokyo Casio Computer Co., Ltd. Hamura Technical Center (change of residence display due to the implementation of the municipal system) (72) Inventor Yoshiru Akita Man 3-2-1 Sakaemachi, Hamura-shi, Tokyo Casio Computer Co., Ltd. Hamura Technical Center (change of housing display due to city system implementation) (72) Inventor Yoshinori Atsumi 3-2-1 Sakaemachi, Hamura-shi, Tokyo Casio Computer Co., Ltd. Hamura Technical Center (change of housing display due to city system implementation) (72) Inventor Toshiharu Tamaki 3-2-1, Sakaemachi, Hamura City, Tokyo Casio Computer Co., Ltd. Hamura Technical Center (house based at city system implementation Display change)

Claims (1)

[Claims] 1. A method of bonding a semiconductor device having a plurality of bumps formed on one surface thereof to a substrate having connection terminal portions corresponding to the bumps, wherein ultraviolet rays are applied so that the bumps are buried on one surface of the semiconductor device. A curable insulating adhesive is applied thickly and each connecting terminal portion of the substrate is formed narrower than the bump, and each bump of the semiconductor device is formed on the substrate through the insulating adhesive. The semiconductor device is characterized in that the semiconductor device and the substrate are pressed relative to each other and aligned with each corresponding connection terminal portion, and in this state, ultraviolet rays are irradiated to cure the insulating adhesive. And board bonding method.