JPH10106907A - Solid phase junctioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To junction on the whole area of junction surface without having non-junctioned part by a method in which a plurality of holes are provided on one of two facing tabular plates, and pressing force, with which the substrate to be junctioned is pushed by the pressing shoes which are inserted to the holes in advance, is applied. SOLUTION: A junction substrate 1 is placed on a tabular plates 3, and the junction substrate 2 is placed on a substrate mounting pedestal 9. Then, a pressing pole guide 10 is attached to a platen guide 8, a mounting screw 14 is driven, substrate pushing shoes 5, springs 6 and spring pressing poles 7 are inserted into a plurality of holes provided on the pressing pole guide 10 in the above-mentioned order, and a pressing plate 13 is placed on the pressing poles 7. Under the above-mentioned state, pressing force is applied to a pressing piston 12 and the pressing plate 13, and compressing stress work between the junction substrate 1 and the junction substrate 2. As a result, the junction substrates 1 and 2 can be junctioned on the whole junction surface without leaving non-junctioned part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid phase joining method, and more particularly to a joining method in which an unjoined portion or a void is not formed on a joining surface.

[0002]

2. Description of the Related Art Conventionally, the solid phase bonding method is generally disclosed in
As described in JP-A-53886, the bonding surface is made convex under reduced pressure so that the bonding surfaces are brought into contact with each other so that the bonding surface interval reaches the interatomic distance.

[0003] Alternatively, as described in JP-A-63-19807, two substrates are warped into a convex shape by vacuum suction, the protruding portions are brought into contact with each other, and the vacuum is released. Was performed in close contact.

[0004] Alternatively, in the literature (J. Appl. Phys. 60 (8),
As shown in 15 October 1986, p. 2987), each bonding surface is subjected to a hydrophilic treatment, and then both bonding surfaces are overlapped and heat-treated at a temperature of 1000 to 1200 ° C.

[0005]

However, the above conventional example has the following inconvenient problems to be solved. That is, (1) it is necessary to perform bonding under reduced pressure in order to prevent adsorption on the bonding surface, so that the alignment operation is not easy, and (2) even a mirror-like and smooth substrate has a large number of engineering points on its surface. When there is undulation, and when viewed from the atomic level, since there are many irregularities having various curvatures, the radius of curvature at the point of contact that is artificially added to the substrate is smaller than the radius of curvature unique to the substrate. If it is large, local unbonded portions are likely to be generated, that is, bubbles are likely to be generated. (3) Heat treatment at a high temperature after the bonding surfaces are overlapped with each other will cause the formed elements and wirings to This has an adverse effect, that is, it is easy to cause destruction of the formed element or disconnection of the wiring.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide a solid-state joining method which enables joining to be performed on the entire joining surface without leaving an unjoined portion of the joining surface.

[0007]

The above object is achieved by the present invention described below. That is, according to the present invention, in the solid-state bonding method, a plurality of holes are provided in at least one of two opposed plate-like platens, and a pair of bonding substrates are placed on the platen so as to face each other. A solid-state joining method, wherein the joining substrate is pressed by a pressing shoe previously inserted into the hole, and a pressing force for bonding between the pressing shoe and the flat platen is applied. Is what you do.

Further, according to the present invention, in the solid-state bonding method, a plurality of holes are provided in at least one of two plate-shaped platens facing each other, and a pair of bonding substrates opposed to each other are provided on the platen. The joining substrate is pressed by a pressing shoe previously placed in the hole, and one substrate is made convex, and in this state, the other flat platen is moved by an external force, and the other flat platen is moved. First, the other substrate placed on the substrate is brought into contact with the convex portion of the one substrate, and further a contact state is generated over the entire joint surface. After the contact on the entire joint surface, a pressing force is further applied by an external force. ,
It discloses a solid-phase joining method characterized by making joining possible.

The present invention provides a method for avoiding the above-mentioned drawbacks, in which one bonding substrate is mounted on a platen plate and the other bonding substrate is formed in a honeycomb shape. The pressing column guide is placed on the flat portion of the pressing column guide so as to face the one bonding substrate, and then the platen is moved so that the bonding surfaces of the bonding substrates come into contact with each other. The other joining substrate surface is pressed by a plurality of pressing shoes previously inserted into the respective holes of the guide. By pressing a spring, which is arranged in a honeycomb shape over the entire joining surface and is provided in the pushing column guide, through the pushing column, the pushing shoe compresses the joined substrates. Therefore, it is possible to apply uniform compressive stress to the bonding substrates over the entire bonding surface. Then, as the number of pressing shoes per unit joining surface is increased, it is possible to gradually reduce the unjoined portion caused by the surface undulation existing on the joining surface.

Further, the length of the pressing shoes of the number positioned at the center of the joining surface so that the joining substrates come into contact with each other at the center of the joining surface when the pushing column is pushed into the stopper by a spring via an external force in advance. The length of the pressing shoe is set in advance by adopting a structure in which the length of the pressing shoe is gradually shortened as it goes to the outer peripheral portion of the joining surface, that is, the length of the pressing shoe is set in advance so as to be convex over the entire joining surface. When the platen on which one of the bonding substrates is mounted is moved by performing adjustment, the contact between the bonding substrates starts at the center of the bonding surface first, and is further compressed by moving the platen. When the force increases, the force gradually spreads to the outer peripheral portion of the joint surface. According to this method, it is possible to perform the bonding while expanding the contact from the central portion to the outer peripheral portion while preventing the generation of bubbles at the bonding interface.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0012]

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

[Embodiment 1] FIG. 1 is a drawing which best illustrates the features of the present invention. In FIG. 1, 1 and 2 are bonding substrates, 3 is a flat platen on which the bonding substrate 1 is mounted,
Reference numeral 5 denotes a substrate pressing shoe that is in contact with the joining substrate 2 and applies a pressing force, 6 denotes a coiled spring that applies a uniform pressing force to the substrate pressing shoe 5, and 7 denotes a spring which is compressed. A spring pressing column for giving a displacement, 8 is a platen guide to serve as a guide when the platen 3 is moved up and down, 9 is a substrate mounting base for mounting the joining substrate 2, 10 is a pressing shoe A pressing column guide 11 composed of a plurality of holes for serving as a guide when the spring 5, the spring 6, and the spring pressing column 7 move up and down, transmits a pressing force to the platen 3 at the time of joining, and has an effect of self-centering. 12 is a pressing piston for applying a pressing force at the time of joining, and 13 is a substrate pressing shoe 5 at the time of joining.
A pressing plate 14 for applying a pressing force to the platen guide 8 is a mounting screw for mounting the pressing column guide 10 to the platen guide 8.

Next, in the above configuration, the mounting screws 14 are removed, the bonding substrate 1 is placed on the platen 3, and the bonding substrate 2 is placed on the substrate mounting base 9, and then the pressing column guide 10 is placed on the platen guide 8. Mounting, mounting screw 1
4 are fastened, and the substrate pressing shoes 5, the spring 6, and the spring pressing columns 7 are inserted into the respective holes provided in the pressing column guide 10 in this order, and the pressing plate 13 is placed on the spring pressing columns 7.
Then, as shown in FIG. 3, a compressive load is applied to the pressing piston 12 and the pressing plate 13 in the direction of the arrow to
Compressive stress acts between the substrate and the bonding substrate 2.

In this embodiment, pn (p;
The junction was performed as follows, using Zn as a dopant and n as Sn as a dopant. That is, an InP (both p-type and n-type) substrate that has been surface-treated in the order of oxygen plasma ashing, cleaning with hydrogen fluoride, and cleaning with flowing water (15 seconds) is used as a bonding substrate, and the bonding method of the present invention is used. While applying an applied stress of about 100 kg / cm ² and simultaneously heating the bonding substrate in an electric furnace at 200 ° C. for 2 hours, an IR camera (infrared camera) was used.
A bond was obtained over the entire surface of the substrate. After that, the bonded substrate was cut into 3 mm × 3 mm by a disco cutter, and the overall thickness was reduced to about 60 μm by lapping polishing (up to 1 μm diamond paste). As a result of the test, diode characteristics indicating electrical junction were obtained.

[Embodiment 2] FIGS. 4 and 6 show the best features of the present invention.
Denotes a bonding substrate, 3 denotes a flat platen on which the bonding substrate 1 is placed, 4 denotes a substrate pressing column for transmitting a pressing force to the bonding substrate 2, and 5 denotes a pressing plate which is in contact with the bonding substrate 2. A substrate pressing shoe for applying pressure, 6 is a substrate pressing shoe 5
A coil-shaped spring for giving a uniform pressing force to the spring, a spring pressing column for giving a displacement to the spring 6 by compression,
Reference numeral 8 denotes a platen guide that serves as a guide when the platen 3 is moved upward and downward. 9 denotes a substrate mounting base for mounting the joining substrate 2. 10 denotes a pressing shoe 5, a substrate pressing column 4, and a spring 6. And a pressing column guide 11 composed of a plurality of holes to serve as a guide when the spring pressing column 7 moves up and down, and transmits a pressing force to the platen 3 during joining,
And a pressing steel ball for applying a pressing force at the time of bonding, 13 a pressing plate for applying a pressing force to the substrate pressing shoe 5 at the time of bonding, and 14 a platen. A mounting screw for mounting the pressing column guide 10 to the guide 8.

Next, in the above configuration, the mounting screws 14 are removed, the bonding substrate 1 is placed on the platen 3, and the bonding substrate 2 is placed on the substrate mounting base 9, and then the pressing column guide 10 is placed on the platen guide 8. Mounting, mounting screw 1
4 is fastened, and the substrate pressing shoes 5, the substrate pressing columns 4, the springs 6, and the spring pressing columns 7 are inserted into the respective holes provided in the pressing column guide 10 in this order, and the pressing plate 13 is placed on the spring pressing columns 7. Place. Thereafter, as shown in FIG. 4, a load is applied to the pressing plate 13 in the direction of the arrow to deform the bonding substrate 2 into a convex shape. In this state, as shown in FIG.
, A pressing load is applied in the direction of the arrow. In the process of applying the pressing load, when the platen 3 moves upward, the contact between the joining substrate 1 and the joining substrate 2 first occurs at the convex portion, and gradually spreads to the peripheral portion of the joining substrate. It happens all over the place. In this state, when the pressing load is further increased in the direction of the arrow as shown in FIG. 6, the bonding substrates 1 and 2 are bonded to each other over the entire surface.

In this embodiment, the bonding between the Si substrates was performed as follows using the method of the present invention. That is,
Oxygen plasma ashing of Si substrate (200 ° C × 20
Min), hydrogen fluoride water (2%) cleaning and running water cleaning (15
Second) and then used as a bonding substrate.
The load per unit area is 120K by the joining method of the present invention.
The bonding substrate was simultaneously heated in an electric furnace at 200 ° C. for 2 hours while applying g / cm ² . When the Si substrate bonded as described above was examined with an IR camera (infrared camera), bonding over the entire surface of the substrate was obtained.

After that, when the bonded substrate was cut into a size of 3 mm × 3 mm by a disco cutter and subjected to a tensile test, a high value of a tensile breaking strength of 250 kg / cm ² was obtained. In this embodiment, the shape of the substrate pressing shoe is circular. However, even if the shape is square or hexagonal, what is intended by the present invention does not change at all.

[0020]

As described above, according to the present invention,
One bonding substrate is placed on a platen plate, and the other bonding substrate is opposed to each other. Since the bonding is performed by applying a compressive stress to the other bonding substrate, the following effects can be obtained. (1) It is possible to bond a bonding substrate having a unique undulation on the bonding surface over the entire bonding surface without leaving an unbonded portion. (2) By increasing the number of substrate pressing shoes per unit bonding area depending on the magnitude of the undulation, that is, by reducing the area of the pressing surface of each independent substrate pressing shoe, the entire surface without leaving unjoined portions. Enable bonding. (3) In a substrate pressing shoe arranged without a gap over the entire surface of the bonded substrate, the length of the substrate pressing shoe is the longest at the center of the bonded substrate, and as it goes to the periphery,
The contact between the bonded substrates is first started at the convex portion by presetting so that the substrate pressing shoe becomes convex as a whole, that is, by applying a compressive stress with a flat platen thereafter. Thus, it is possible to obtain a bubble-free bond over the entire surface while gradually expanding to the periphery.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating features of a bonding method according to a first embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 3 is a cross-sectional view showing a state in which bonding is performed by applying pressure to an adhesive substrate.

FIG. 4 is a cross-sectional view illustrating features of a bonding method according to a second embodiment of the present invention.

5 is a view taken in the direction of arrows BB in FIG. 4;

FIG. 6 is a cross-sectional view showing a state in which pressure is applied to an adhesive substrate to perform bonding.

FIG. 7 is a view taken in the direction of the arrows CC in FIG. 6;

[Explanation of symbols]

 Reference Signs List 1, 2 bonding substrate 3 platen 4 substrate pressing column 5 substrate pressing shoe 6 spring 7 spring pressing column 8 platen guide 9 substrate mounting pedestal 10 pressing column guide 11 pressing steel ball 12 pressing piston 13 pressing plate 14 mounting screw

Claims (7)

[Claims] In a solid-state bonding method, a plurality of holes are provided in at least one of two opposed plate-like platens, and a pair of bonding substrates are placed on the platen so as to face each other. A solid-state joining method, wherein the joining substrate is pressed by a pressing shoe previously inserted into the hole, and a pressing force for bonding between the pressing shoe and the flat platen is applied. 2. In the solid-state joining method, at least one of two opposed plate-like platens is provided with a plurality of holes, and a pair of joining substrates is placed on the platen so as to face each other. The joining substrate is pressed by a pressing shoe previously inserted into the hole, one of the substrates is made convex, and in this state, the other plate-shaped platen is moved by an external force and placed on the other plate-shaped platen. The other substrate that is placed is first brought into contact with the convex portion of one substrate, and further a contact state is generated over the entire bonding surface. After contacting the entire bonding surface, a pressing force is further applied by an external force to perform bonding. A solid-state bonding method characterized by being made possible. 3. The method according to claim 1, wherein the pressing shoe inserted into the hole moves along the hole by an external force. 4. The method according to claim 1, wherein the plurality of pressing shoes are arranged in a honeycomb shape. 5. The solid-state joining method according to claim 1, wherein the shape of the flat pressing surface of the pressing shoe is a circle, a square, or a hexagon. 6. The solid-phase joining method according to claim 1, wherein a pressing force is applied to the pressing shoe by an external force via a spring. 7. The solid phase joining method according to claim 6, wherein the spring is a circular coil spring.