JPH01146322A - Manufacture of solid coupled body - Google Patents

Abstract

PURPOSE:To make it possible to couple 2 solid bodies or more by a solid phase having a desired nature suitable for the purpose of use of a solid coupling without giving a change to the forms, properties and so on of the solid bodies to be coupled by a method wherein the two solid bodies or more are contraposed to each other at a necessary proximity interval and the solid phase is deposited and grown at the proximity interval part from the vapor phase of a necessary gas system. CONSTITUTION:Two solid bodies 1 and 2 or more are contraposed to each other at a necessary proximity interval L, a solid phase 3 is deposited and grown at the proximity interval part from the vapor phase of a necessary gas system and said solid bodies 1 and 2 are coupled with each other into a solid coupling 10. For example, two pieces of the Si semiconductor substrates 1 and 2, one side of which is 2mm or thereabouts square, are contraposed to each other as solid bodies in a reduced CVD reaction furnace in almost parallel to each other at the interval L of about 2mum. Then, the poly Si 3 is deposited and grown at the part of the interval L as a solid phase at a temperature of 630 deg.C, in 0.6Torr as a gas system, with He as a base, using 20% of SiH4 gas, at the amount of supply gas of 300cm<3>/min and by a reduced CVD method and two pieces of the substrates 1 and 2 are coupled with each other to obtain the solid couple 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a solid-state bonded body for integrally bonding, for example, silicon semiconductor substrates.

(Prior Art) Conventional techniques for integrally bonding solid bodies include, for example, a bonding method using an adhesive, and a method in which parts of two or more crystal bodies to be joined are brought into contact and heated to a temperature above the melting point. ,
Alternatively, there is a hot press method in which two or more solids are heated in a vacuum to near their melting point to perform diffusion bonding, or simultaneously pressurized.

(Problems to be Solved by the Invention) Conventional bonding methods using adhesives can be said to be an easy method if the use of the adhesive matches the purpose of use of the solid composite. Depending on the purpose of use, the use of an adhesive that is a foreign substance may be undesirable, and in such cases it cannot be used.

In addition, in the method of heating the part of the crystal to be joined above the melting point, part or all of the solid will melt, so the shape and properties of the melted part will be different from those before joining, causing distortion and deformation. will occur.

Furthermore, in diffusion bonding methods such as hot pressing, it is usually necessary to heat the solids to be bonded to near their melting point, which can lead to a decrease in dimensional accuracy due to deformation such as creep, and a decrease in bond strength due to increased residual stress. It will happen.

In each of the above-mentioned methods, the material of the joining body that can be formed between the joining bodies is extremely limited.

Incidentally, in recent years, in a conductivity modulated MO3FET, which is a type of semiconductor device as shown in FIG.
A technique has been considered in which a polycrystalline silicon layer 17 containing a large amount of carrier recombination centers is formed between the base region 5 and the second n-base region 16 for the purpose of preventing latch-up. In FIG. 4, 18 is a MO8FET region, and p-type channel region 1
9, an n+ source region 21, a gate insulating film 22, a gate electrode 23, and the like.

And this interlayer polycrystalline silicon structure is 0MO8IC
Because it is highly effective in preventing latch-up, forming a monocrystalline silicon-polycrystalline silicon-monocrystalline silicon structure is an extremely important technology for the production of highly reliable 0MO8 (C). It has become.

However, the above-mentioned bonding method using an adhesive cannot be applied to such an interlayer polycrystalline silicon structure, and it is difficult to adopt other methods because they have the various problems mentioned above. . Moreover, even in conventional semiconductor process technology, there is no technology for depositing a polycrystalline semiconductor on a single-crystal semiconductor substrate and further forming a single-crystal semiconductor thereon.

On the other hand, the realization of three-layer structures or more multilayer structures such as single crystal semiconductor - amorphous semiconductor - single crystal semiconductor, single crystal semiconductor - metal - single crystal semiconductor, single crystal semiconductor - intermetallic compound - single crystal semiconductor, etc. This technology is considered essential for the development of functional electronic devices.

Here, the present invention provides a solid bond that can be bonded with required dimensional accuracy without changing the shape, properties, etc. of the solid to be bonded, and that has desired properties suitable for the purpose of use of the solid bond. It is an object of the present invention to provide a method for producing a solid-state bonded body capable of bonding two or more solids through a phase.

[Structure of the Invention] <Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention arranges two or more solids opposite each other at a required close distance, and connects a required gas system to the close space. The gist of the method is to grow a solid phase by precipitation from a gas phase and combine two or more solids to form a solid composite.

(Function) The gas phase of the required gas system is raised to a temperature at which the same phase is precipitated, and the solid phase is precipitated and grown in the closely spaced parts of two or more solids, and the two or more solids are combined, forming a solid composite. be done. Since the reaction temperature for precipitating the solid phase from the gas phase is usually lower than the melting point of the solids to be bound, changes in the shape, dimensions, etc. of the solids to be bound can be avoided.

In addition, especially in the field of semiconductor device manufacturing, it is relatively easy to deposit polycrystalline semiconductors, amorphous semiconductors, and required insulators as a solid phase by selecting the gas system and reaction temperature, so solid composites are used. It is possible to combine two or more solids by appropriately selecting a solid phase having desired properties suitable for the purpose.

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

First Embodiment This embodiment will be explained using FIGS. 1(a) and 1(b).

This embodiment is applied to bonding silicon semiconductor substrates.

As shown in Figure 1(a), first, as a solid, one side is 2.
Two silicon semiconductor substrates 1.2 each measuring about mm square were placed substantially parallel to each other with an interval of about 2 μm in an LP (low pressure') CVD reactor (not shown). Next, Fig. 2(b)
As shown in the figure, the temperature is 630℃ and the gas system is 0.6T.
LI'CVD using Orr, He base, 20% s + 84, supply gas ff1300cm3/min
As a result, polycrystalline silicon 3 was precipitated and grown as a solid phase in the spaced areas, and the two semiconductor substrates 1.2 were bonded to form a solid bonded body 10.

During the precipitation and growth of this binding solid phase, sometimes “
In some cases, whiskers were formed, but those whiskers disappeared by heat treatment at a temperature higher than the deposition temperature.In addition, at this time, the open substrates 1 and 2 were applied parallel to each other. By applying pressure, the effect of eliminating "whiskers" was increased.

Also, even if the spacing is changed to 1μm, 3μm, 5μm,
By increasing the precipitation growth time accordingly, a strong solid bond 10 could be obtained.

As the solids of the second embodiment, two silicon semiconductor substrates 1.2 each having a side of approximately 2 mm square were used, as in the first embodiment (FIG. 1), and only the generation temperature was 560°C. With other gas conditions and other conditions similar to those of the first embodiment, amorphous silicon is grown in the same phase in the spaced areas, and the two semiconductor substrates 1.2 are bonded to form a solid bond. I got a body.

As the solid bodies of the third embodiment, two silicon semiconductor substrates 1.2 similar to those of the first embodiment (FIG. 1) were used. 0.75 Torr SS i as a gas system at a temperature of 750°C
1-12 C12 and NH3 are respectively supplied as gas fjt
70cm3/min and 700cm3/min
n, and silicon nitride is deposited and grown as a solid phase in the spaced areas by LPGVD to form two semiconductor substrates 1.
．． 2 was bonded to obtain a strong solid bond.

Fourth example This embodiment will be explained using (a) and (D) of FIG.

In this embodiment, a spacer 6 is used between two solid bodies in order to maintain a stable distance between the two solid bodies when manufacturing the solid body 20.

The method for forming the spacer 6 will be described using two solid silicon semiconductor substrates 4.5, which are placed parallel to each other with an interval of about 2 .mu.m and are bonded together.

The spacer 6 is formed by depositing a polycrystalline silicon film with a thickness of about 2 μm on the bonding surface of one of the silicon semiconductor substrates 4 by LPGVD, and then photobuttering and etching it to the desired position. A desired shape can be formed.

Examples of conditions include a temperature of 620℃ and a gas system of 0.6T.
orr, He-based, 20% Si'H4, LP
A polycrystalline silicon film is deposited to a thickness of about 2 μm on the silicon semiconductor substrate 4 by GVD. Next, after performing desired photopatterning on this, CF4 (9
5%) +02 (5%) gas, 150W, 70℃, 0.4
Spacers 6 made of a polycrystalline silicon film can be formed by performing gas etching under Torr conditions.

Then, with the spacer 6 formed as described above,
By performing the bonding process according to any one of the first embodiment, second embodiment, or third embodiment while keeping the distance between the two silicon semiconductor substrates 4.5 stable, the distance between the two silicon semiconductor substrates 4.5 is fixed. ,
A solid phase 7 consisting of polycrystalline silicon, amorphous silicon or silicon nitride can be deposited and grown to bond the two semiconductor substrates 4.5 to obtain a solid state combination 20.

Note that the film for forming the spacer 6 is not limited to a polycrystalline silicon film, but may also be a film that can be formed on the surface of a solid to be bonded with its thickness controlled with desired accuracy, and that can be patterned by etching. Any material can be used as long as it can stably maintain the distance between the two solids during the bonding process.

Taking the case of bonding a silicon semiconductor substrate as a solid as an example, the film for forming the spacer 6 may be a thermal silicon oxide film, a silicon nitride film that can be formed by LPGVD, or a normal pressure C
Silicon oxide film, PSG film, BS that can be formed by VD
Any G film, BPSG film, metal film, alloy film, etc. that can be formed by sputtering, EB evaporation, etc. can be used, and spin-on glass or polymer films that can be formed by spin coding can also be used. be able to.

Further, when a film that can be selectively dissolved is used as the film for forming the spacer 6, only the spacer 6 can be removed as necessary after the solid bond is formed. For example, if two silicon semiconductor substrates are integrally bonded by polycrystalline silicon using a spacer formed of a thermal silicon oxide film, for example, ammonium fluoride:hydrofluoric acid = 10.5 mol = 3 mol The upper etchant allows the spacer to be selectively etched away at room temperature.

Fifth Embodiment This embodiment will be explained using FIGS. 3(a) and 3(b).

In this embodiment, when bonding solids having a relatively large area to be bonded, grooves with openings at the end surfaces are formed in the bonded surfaces to allow gas to react and precipitate the solid phase for bonding over the entire surface of the bonded surfaces. It was designed to ensure a reliable connection.

For example, when bonding two silicon semiconductor substrates 8 and 9 each having a side of about 4 mm, one silicon semiconductor substrate 8 is photo-patterned, and then, for example,
9%HF: 69.5%1-+03: CH3C00
Width 1 mm by wet etching using H=1:2:1 etchant.

A groove 11 having a depth of 5 μm and having a cross shape when viewed from above was formed. Further, CvD is applied to the bonding surface of the silicon semiconductor substrate 8
By depositing a silicon oxide film with a thickness of about 2 μm, and then photopatterning and etching it, spacers 12 with a negative side of about 3 μm and a thickness of about 2 μm were formed at the four corners of the square substrate 8. .

Then, with the spacer 12 keeping the distance between the two silicon semiconductor substrates 8.9 stable, the temperature is set at 620°C.
0.6 Torr for gas system.

Polycrystalline silicon 13 is deposited and grown as a solid phase in the space between the two silicon semiconductor substrates 8.9 by LPGVD using He-based 20% SiH4 to form a strong solid bond 30. I got it.

According to each of the embodiments described above, it is possible to manufacture a strong solid bond determined by the bonding strength between the solid to be bonded and the precipitated solid phase for bonding, and the strength of the solid to be bonded and the precipitated solid phase for bonding themselves. be. That is, if the solid phase is deposited and adhered to the solid to be bonded from the gas phase, a solid bonded body having the bonding strength due to the solid phase can be formed.

Note that the solid to be bonded is not limited to the silicon semiconductor substrate mentioned in each of the above-mentioned examples, but may also include other semiconductors, metal oxides, ceramics, organic materials, crystalline and amorphous organic materials, etc. Any substance can be used as the solid phase for bonding, as long as it can be deposited from the gas phase and attached to the solid.

Furthermore, all devices that utilize the phenomenon of precipitating a solid phase from a gas phase, such as various CVD devices, epitaxial film forming devices, various PvD devices, and sputtering film forming devices, can be used. can.

Moreover, two or more solids to be bound can be bound in any relative positional relationship.

[Effects of the Invention] As explained above, according to the present invention, a solid phase is precipitated and grown from a gas phase of a required gas system in a closely spaced part of two or more solids to bond the two or more solids together. Therefore, heating of the solid to be bonded to its melting point can be avoided, and changes in the shape, properties, etc. of the solid to be bonded can be prevented and bonding can be performed with the required dimensional accuracy. In addition, especially in the field of semiconductor device manufacturing, it is relatively easy to precipitate polycrystalline semiconductors, amorphous semiconductors, and required insulators as the same phase by selecting the gas system and reaction temperature. There is an advantage that two or more solids can be combined by appropriately selecting the same phase having desired properties suitable for the purpose.

[Brief explanation of the drawing]

FIG. 1 is a process diagram for explaining the first to third embodiments of the method for producing a solid composite according to the present invention, and FIG. 2 is a process diagram for explaining the fourth embodiment of the present invention. , 3rd
FIG. 4 is a process diagram for explaining a fifth embodiment of the present invention, and FIG. 4 is a longitudinal sectional view showing an example of a conventional semiconductor device to which the present invention can be applied. 1.2.4.5.8.9: Silicon semiconductor substrate (solid)
, 3.13: Polycrystalline silicon (solid phase), 7: Solid phase, 10.20.30: Solid bond. Figure 1 (a) Figure 1 (b) Figure 2 (a) Day 2 (b)

Claims (1)

[Claims] The method is characterized in that two or more solids are placed opposite each other at a required close distance, and a solid phase is deposited and grown from the gas phase of a required gas system in the close space to combine the two or more solids to form a solid bond. A method for producing a solid-state composite.