JPS6246996A - Production of thin film of single crystal having large area - Google Patents

Abstract

PURPOSE:To easily obtain a thin film of a silicon single crystal having a large area by joining the confronting edges of plural wafers of silicon single crystals to each other to form a substrate and by epitaxially growing silicon on the substrate by a vapor phase growing method. CONSTITUTION:Plural wafers 1 of silicon single crystals are linearly arranged and the confronting edges are brought into contact with each other, heated to a high temp. and bonded to each other by melting under pressure. Silicon 3 is epitaxially grown on the resulting substrate by a vapor phase growing method. Thus, a thin film of a silicon single crystal having a large area is easily obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is applicable to contact type image sensors, thin film type thermal heads, and drive circuits used in facsimile machines, etc.
Concerning the method of reporting the theft of Ashimen Nagisafu Hσ凰鈷書TSAha.

Conventional technology As a contact type image sensor using silicon single crystal, National Technical Re
port.

VOl, 31, A2, April, 1985. pp1
It was introduced in an article titled ``Bipolar IC contact type image sensor'' in Ryo 9-188. This image sensor is made from 7 silicones fabricated using an IC process.
Chips of X1.7- were cut, eight of these chips were arranged linearly on an alumina substrate, and fixed with an epoxy adhesive. This reduces the connection error by 10μm.
It is believed that it can be kept below. Also, ICC
When cutting chips from sea urchin, the separation layer between the light-receiving windows is cut so as not to degrade the performance of the photosensor located at the edge of the chip.

When compared to CdS contact sensors and amorphous silicon contact sensors, such contact image sensors are capable of high-speed reading and are equipped with a circuit for scanning linearly arranged photosensors on a chip. It has the advantage of being able to be mounted on top.

Problems to be Solved by the Invention However, when manufacturing a contact image sensor by arranging silicon IC chips in a straight line, it is necessary to accurately read the image of the connection point and to reduce reading errors. Disconnect, connect.

There is a problem in that it requires extreme precision for fixing, making it expensive.

It is clear that such problems arise because there are no long silicon single crystal wafers. Recently, it has become possible to cut long silicon wafers from pulled cylindrical silicon bulk, but the silicon wafers obtained in this way become even more expensive.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an improved wafer manufacturing method that can easily produce a large-area single-crystalline silicon thin film.

Means for Solving the Problems The wafer manufacturing method according to the present invention involves arranging a plurality of silicon single crystal wafers in a straight line, bringing the wafer end faces into contact with each other, and applying pressure to the end faces under high temperature to face each other. The method includes a step of fusing the end faces and epitaxially growing silicon on the bonded wafer surfaces by vapor phase growth.

The bonded portions of the wafer edges bonded by thermocompression disappear during the epitaxial growth process of silicon, resulting in a large-area single-crystal thin film having no crystal boundaries.

Embodiment An embodiment of the present invention will be described with reference to FIG. Code 1 has a (001) plane, length 2cWI, width 1cM,
A silicon single crystal wafer with a thickness of 100 μm is shown.

The (110) end faces of such a single crystal wafer 1 are bonded together by thermocompression at a temperature of 100o'C in a hydrogen atmosphere to obtain a substrate of linearly arranged wafers having bonded portions 2. On the surface of such a wafer substrate, a silicon epitaxial layer 3 having a thickness of 20 μm is formed by low pressure vapor phase growth using silane gas. In the process of growing the epitaxial layer 3, as shown in an enlarged view in FIG. 2, crystal discontinuities (junctions) are buried and disappear, resulting in a large-area single-crystal thin film. In the process of such epitaxial crystal growth, grooves and foreign matter on the crystal surface are buried and a continuous single crystal surface is obtained, for example, J, Mppl, P
hy! ! , , 55 (10).

15 May 1984. pp 3868-3870
It has been clarified in

Next, a method for linearly arranging and bonding a plurality of silicon single crystal wafers will be described. Figure 3 shows a jig for this purpose, including a carbon storage box 4 for vertically stacking and storing silicon wafers, and a carbon slider for applying uniaxial pressure to the end faces of the stacked silicon wafers. 6 and a weight e made of carbon. Several silicon wafers 1 are stacked vertically in a storage box 4, pressure is applied from the slider 6 and weight 6 on top of the wafers, and the wafers are placed in a vertical electric furnace and the temperature is raised to 1000°C in a hydrogen gas atmosphere. let As shown in an enlarged view in FIG. 4, the end surface of the silicon wafer 1 subjected to uniaxial pressure in the storage box 4
Since extremely large pressure is applied to the contact portion due to the unevenness, the contact portions on both end faces melt even at 1000'C, the contact area expands, and they are fused together.

Another series of end face bonding methods is shown in FIG. On the end surfaces of the silicone wafers 1 to be joined to each other, 60
Metals that alloy with silicon at high temperatures of about 0°C to 100°C, such as gold and indium.

A coating 7 made of tin or the like is formed in advance by vapor deposition or the like. When such a silicon sea urchin/S1 is thermocompression bonded by the method described above, the end surfaces of the silicon wafers 1 facing each other are alloyed with the metal coating 7 and bonded. In this case, if the alloying temperature is set lower than the melting point of silicon, silicon wafers can be bonded at lower temperatures and pressures than the bonding method described above.
1 can be fused together.

Effects of the Invention As described above, the method for manufacturing Uninow according to the present invention involves bonding the opposing end surfaces of a plurality of silicon single crystal wafers to each other, and epitaxially growing silicon by vapor phase growth using the bonded wafers as a substrate. As a result, crystal discontinuities are buried during the epitaxial growth process, and a silicon single crystal thin film with a large area can be easily obtained.

By forming a photosensor and a scanning circuit on the thus obtained large-area thin film single crystal using the ICj process, a contact type silicon single crystal image sensor that does not require high-precision cutting, gluing, or fixing can be obtained. I can do it. Furthermore, a thin film type thermal head drive circuit and the like can be obtained in a similar manner.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a row of silicon wafers manufactured according to the present invention, FIG. 2 is an enlarged sectional view of the wafer portion of FIG.
The figure is a perspective view of an example of a wafer arrangement jig used in the present invention, FIG. 4 is an enlarged sectional view of a wafer end surface joint in an embodiment of the present invention, and FIG. FIG. 3 is an enlarged cross-sectional view of a wafer end surface joint. 1...Silicon single crystal wafer, 2...
Junction, 3...Silicon epitaxial layer, 4
... Silicon wafer storage box, 5 ... Slider, 6 ... Weight, 7 ... Metal coating. Name of agent: Patent attorney Toshio Nakao and one other person

Claims (2)

[Claims] (1) A plurality of silicon single crystal wafers are arranged in a straight line, their opposing end surfaces are brought into contact with each other, and the opposing end surfaces are fused together by applying pressure to the end surfaces under high temperature. A method for manufacturing a large-area thin film single crystal wafer in which silicon is epitaxially grown by vapor phase growth on multiple silicon single crystal wafers fused to a silicon wafer. (2) A method for manufacturing a large-area thin film single crystal wafer according to claim 1, wherein a metal coating that alloys with silicon at high temperatures is formed in advance on the end faces of a plurality of silicon single crystal wafers.