JPH0832038A - Manufacture of stuck soi substrate and stuck soi substrate - Google Patents

Abstract

PURPOSE:To provide a manufacturing method of a stuck SOI substrate having a diameter equal to or larger than the large caliber of a single crystal wafer which can not be manufactured by techniques. CONSTITUTION:Polycrystalline silicon is fused by using a quartz crucible having a large caliber, and a polycrystalline silicon rod is obtained by cooling. The rod is sliced and subjected to mirror polishing, and a retaining substrate 5 is formed. When the crystal orientation of a single crystal silicon rod grown by a CZ method is <111>, the rod is worked into a regular hexagonal pole, sliced, and subjected to mirror polishing, and a single crystal silicon wafer 7 is formed. The wafer 7 is subjected to oxidation treatment, and stuck on the retaining substrate 5 without generating a gap, and an SOI substrate is constituted. The upper surface of the wafer 7 is polished to obtain a specified thickness. Glass, ceramics, etc., may be used as a retaining substrate. By sticking a single crystal silicon wafer 8, which is worked into an equilateral triangle, on the periphery of the single crystal silicon wafer 7, the area of the retaining substrate 5 can be effectively used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bonded SOI substrate and a bonded SOI substrate.

[0002]

2. Description of the Related Art It is advantageous to form various elements in a thin semiconductor layer provided on an insulating material in terms of element characteristics and element isolation, rather than forming an integrated circuit on a bulk semiconductor substrate. . From this point of view, an SOI (silicon on i) structure in which a single crystal silicon layer for forming an element is provided on a single crystal silicon substrate through an insulating film of SiO ₂ is provided.
nsulator) structure is used. The SOI
Among the methods for obtaining the structure, the method of sticking a single crystal silicon wafer provides an SOI active layer with high crystallinity, the thickness of the active layer can be set to some extent, and the thickness of the buried oxide film can be set. It has the advantage that it can be set arbitrarily.

[0003]

However, the SOI substrate manufactured by the bonding technique has the following problems. (1) Bonded SOI substrates are likely to have defects at the bonding interface during bonding. A typical defect is the occurrence of voids, which are defective bonding regions, and the non-defective rate decreases as the diameter of a bonded wafer increases. (2) When single crystal silicon is used for the supporting substrate, the diameter of the SOI substrate is restricted by the diameter of the single crystal that can be manufactured by the technology of the generation, and the cost is very high. In the final process of manufacturing electronic equipment, SO
After the chips such as CPU and memory are individually manufactured using the I substrate, these chips are arranged at predetermined positions to form a system.

The present invention has been made in view of the above-mentioned conventional problems, and the bonding S having a diameter equal to or larger than that of a large-diameter single crystal wafer which cannot be manufactured by the technology of the generation.
An object is to provide a method for manufacturing an OI substrate and a bonded SOI substrate, and further to provide a bonded SOI substrate for a system-on-chip capable of forming a plurality of types of devices on one bonded SOI substrate. I am trying.

[0005]

In order to achieve the above object, a method for manufacturing a bonded SOI substrate according to the present invention comprises:
After bonding a dislocation-free single crystal silicon wafer with a specific shape that has been mirror-finished and oxidized to a support substrate made of large-diameter polycrystalline silicon, glass, ceramics, or metal that has been mirror-finished, A single crystal silicon wafer is polished to a predetermined thickness, and in such a configuration, the specific shape is a regular hexagon, a regular square, a rectangle, or a regular triangle. Further, the bonded SOI substrate according to the above-mentioned manufacturing method is a supporting substrate made of polycrystalline silicon, glass, ceramics or metal having a diameter equal to or larger than that of a large-diameter single crystal silicon wafer which cannot be manufactured by the technology of the generation. A plurality of dislocation-free single crystal silicon wafers processed into a specific shape, which are bonded together via an oxide film, or a plurality of dislocation-free single crystals necessary for constructing an electronic system on the supporting substrate. The silicon wafers were each bonded to a predetermined position.

[0006]

The area of the single crystal silicon wafer processed into a specific shape is sufficiently smaller than the area of the supporting substrate made of a large-diameter polycrystalline silicon wafer or the like. According to the above configuration, since a single crystal silicon wafer which has been processed into a regular hexagon, a regular square, a rectangle, or a regular triangle and subjected to an oxidation treatment in advance is used as an SOI wafer, the same is applied to a large-diameter support substrate. Bonding is easier than when bonding large diameter SOI wafers,
Generation of voids is reduced. Further, by using polycrystalline silicon, glass, ceramics, or metal for the supporting substrate, the SOI wafer can be bonded to a supporting substrate having a large diameter which cannot be obtained with single crystal silicon without any gaps. The area can be effectively used. Furthermore, a system-on-chip SOI substrate can be obtained by bonding a plurality of types of dislocation-free single crystal silicon wafers to predetermined positions on a large-diameter support substrate.

[0007]

EXAMPLES Examples of a method for manufacturing a bonded SOI substrate according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing a manufacturing process of a support substrate. First, in FIG. 1A, a quartz crucible 1 having a large diameter such as 24 inches is filled with polycrystalline silicon 2 and melted by a heater 3. When this is cooled and taken out from the quartz crucible 1,
24-inch polycrystalline silicon rod 4 shown in FIG.
Is obtained. When this polycrystalline silicon rod 4 is sliced and mirror-finished, a 24-inch supporting substrate 5 shown in FIG. 1C is obtained. The thickness of the support substrate 5 is 1 mm,
The flatness (TTV) is less than 1 μm. As the method for manufacturing the polycrystalline silicon rod, the CZ method, Bridgman method, cairoporous method, or pedestal method may be used.

FIG. 2 is an explanatory view showing a manufacturing process of an SOI wafer. FIG. 2 (a) shows the growth of single crystal silicon by the CZ method. The polycrystalline silicon filled in the quartz crucible 1 is melted by the heater 3 and the seed crystal is immersed in the melt to form, for example, 6
An inch single crystal silicon rod 6 is grown. This single crystal silicon rod is processed into a regular hexagonal column, a regular square column or the like based on the crystal orientation. In FIG. 2B, the crystal orientation is <11.
The state which processed the single crystal silicon rod 6 of 1> into the regular hexagonal column is shown. If the rod has a crystal orientation of <100>, it may be processed into a regular square pole. Thus, by processing the single crystal silicon rod into a specific shape, it is not necessary to process the orientation flat or notch. When this rod is sliced and mirror-finished, it is shown in Fig. 2 (c).
A regular hexagonal single crystal silicon wafer 7 having a thickness of 500 μm is obtained as shown in FIG. The wafer 7 is subjected to an oxidation treatment to form an oxide film (SiO ₂ ) having a thickness of 1000Å.

The single crystal silicon wafer is attached to a supporting substrate 5 as shown in FIGS. FIG. 3 shows a state in which a regular hexagonal single crystal silicon wafer 7 is bonded to the support substrate 5 without any space, and an equilateral triangular single crystal silicon wafer 8 is bonded to the remaining peripheral part without any space. In FIG. 4, 7a is single crystal silicon,
7b is an oxide film. As shown in FIG. 5, this is ground until the thickness of the active layer of the single crystal silicon wafers 7 and 8 becomes 20 μm. Next, the active layers of the single crystal silicon wafers 7 and 8 are ground to a thickness of 1 μm and bonded S
The OI substrate was completed. When a single crystal silicon wafer is attached to the support substrate 5, a gap may be provided between the wafers. In addition, the thickness of the active layer is 0.1μ.
When finishing to about m, plasma etching is performed on the surface of the active layer.

FIG. 6 is an explanatory diagram of a system-on-chip SOI substrate, in which a plurality of types of single crystal silicon wafers are bonded to a supporting substrate 5 via an oxide film. For example,
The single crystal silicon wafer 9 has a resistivity of 1 to 1 for CPU.
The resistivity of the single crystal silicon wafer 10 is 2 Ωcm and the resistivity of the single crystal silicon wafer 10 is 10 to 15 Ωcm. All of these wafers are chip-sized,
Since the electronic systems are bonded to the final positions, the system is completed by a pair of wafers 11 or a group of wafers. In such a bonded SOI substrate, conventional wiring is unnecessary except for a part.

In this embodiment, a polycrystalline silicon wafer having a diameter of 24 inches is used as the supporting substrate, but the supporting substrate is not limited to this, and for example, a polycrystalline silicon wafer having a diameter of 32 inches, a glass plate, a ceramic plate or a metal plate can be used. Large diameter wafers available in that generation can be used. Further, the manufacturing method according to the present invention may be applied when the single crystal silicon wafer not subjected to the oxidation treatment and the supporting substrate are bonded together.

[0012]

As described above, according to the present invention, a single crystal silicon wafer is used which is made of polycrystalline silicon, glass, ceramics or metal for a supporting substrate of a bonded SOI substrate and which is processed into a specific shape. Since a plurality of substrates are bonded together, a large-diameter SOI substrate, which cannot be realized when single crystal silicon is used as the supporting substrate, can be obtained with a high yield rate. Further, by manufacturing the system-on-chip SOI substrate using the above method, the productivity of the electronic system can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a manufacturing process of a support substrate.

FIG. 2 is an explanatory diagram showing a manufacturing process of an SOI wafer.

FIG. 3 is an explanatory diagram showing a state where an SOI wafer is attached to a supporting substrate.

FIG. 4 is a cross-sectional explanatory diagram of a bonded SOI substrate.

FIG. 5 is an explanatory diagram showing a state in which an active layer of an SOI substrate is ground.

FIG. 6 is an explanatory diagram of a system-on-chip SOI substrate.

[Explanation of symbols]

 4 Polycrystalline silicon rod 5 Support substrate 6 Single crystalline silicon rod 7,8,9,10 Single crystalline silicon wafer 7b Oxide film

Claims (4)

[Claims] 1. A dislocation-free single crystal silicon wafer having a specific shape that has been mirror-finished and oxidized is bonded to a support substrate made of mirror-finished large-diameter polycrystalline silicon, glass, ceramics or metal. Then, the method for manufacturing a bonded SOI substrate, which comprises polishing the dislocation-free single crystal silicon wafer to a predetermined thickness. 2. The method for manufacturing a bonded SOI substrate according to claim 1, wherein the specific shape is a regular hexagon, a regular square, a rectangle or a regular triangle. 3. A support substrate made of polycrystalline silicon, glass, ceramics, or metal having a diameter equal to or larger than that of a large-diameter single crystal silicon wafer that cannot be manufactured by the technology of the generation, and a plurality of substrates are processed into a specific shape. A bonded SOI substrate in which individual dislocation-free single crystal silicon wafers are bonded via an oxide film. 4. The bonded SOI according to claim 3, wherein a plurality of types of dislocation-free single crystal silicon wafers necessary for constructing an electronic system are bonded to predetermined positions on the supporting substrate, respectively. substrate.