JPH05259011A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To precisely control processes and to facilitate reading of numbers, regarding the SOI substrate which is used for formation of a device in the semiconductor layer formed on an insulating film, and its manufacture. CONSTITUTION:There is no insulating films 14a and 14b on a part or whole area of process monitoring parts 12a to 12e, and under a numbering part 13, and a bulk semiconductor layer is formed thereon. A part or whole part of the process monitoring parts 12a to 12e and the element forming region other than the numbering part 13 are constructed in such a manner that they have the insulating films 14a and 14b under them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and particularly to SOI (Silicon On Insulator / Semi
onductor On Insulator) Substrate and manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, when manufacturing an SOI device, C
As a process monitor for film thickness control, alignment, etc. in the film forming process by VD method, thermal oxidation process, lithography process, etc., a bulk substrate is flown at the same time as an SOI substrate, and process conditions are set based on the bulk. Was.

The reason for this is that it is difficult to optically measure the thickness of the uppermost portion of the SOI substrate due to the presence of an insulating film as a base and to perform alignment.

[0004]

The conventional method of manufacturing an SOI device has the following problems. As a process monitor, a bulk substrate must be flown at the same time as the SOI substrate, so that the number of processed lots increases accordingly. As a result, TAT (TurnAround Ti
The cost increases as me) increases.

Since the process parameters such as the oxide film formation rate are slightly different between the SOI substrate and the bulk substrate, it is difficult to precisely control the process. In the SOI substrate, since the upper semiconductor layer is thin, the numbering made up of the lot number and the wafer number is very difficult to read, and the mistake of the wafer number occurs.

The present invention solves the above problems and enables the process to be precisely controlled and the numbering to be easily read, and a semiconductor device and its manufacturing method, particularly an SOI substrate and its manufacturing method. The purpose is to provide.

[0007]

In order to achieve the above object, a semiconductor device and a method of manufacturing the same according to the present invention are
Configure as follows.

(1) An SOI substrate used for forming a device in a semiconductor layer formed on an insulating film, wherein there is no insulating film under a part or all of a process monitor section and a numbering section. , A bulk semiconductor layer, and part or all of the process monitor portion and the element forming region other than the numbering portion are configured to have an SOI structure having an insulating film thereunder.

(2) In the method of manufacturing an SOI substrate according to (1) above, a step of forming a mask pattern covering a part or all of the process monitor section on the surface of the semiconductor substrate and the numbering section, and oxygen on the entire surface. Alternatively, the method may include a step of implanting nitrogen ions and a step of performing heat treatment to form an insulating film in the semiconductor substrate directly under a part or all of the process monitor portion and an element forming region other than the numbering portion. Constitute.

(3) In the method of manufacturing an SOI substrate according to (1) above, a part or all of the process monitor portion on the surface of the first semiconductor substrate and an element forming region other than the numbering portion are selectively oxidized. To form an oxide film, planarize the first semiconductor substrate, bond the second semiconductor substrate to the surface of the first semiconductor substrate, and thin the second semiconductor substrate. Configure to include.

[0011]

1 is a diagram showing the basic structure of the present invention, FIG. 1 (a) is a plan view, and FIG. 1 (b) is a sectional view taken along line XX '.

In the figure, 11 is an SOI substrate, 12 is a process monitor section, 13 is a numbering section, and 14 is an insulating film. As shown in FIG. 1, in the SOI substrate according to the present invention,
There is no insulating film 14 immediately below the process monitor unit 12 and the numbering unit 13, and the semiconductor device is a bulk semiconductor.

As a result, it becomes unnecessary to flow a bulk substrate at the same time as the SOI substrate as a process monitor. Therefore, the TAT of the SOI element can be shortened and the cost can be reduced.

Further, since the process monitor section 12 is formed on the SOI substrate 11, it becomes possible to precisely control the process. Furthermore, since the numbering part 13 is formed in bulk, the problem that the numbering is difficult to read is eliminated, and it is possible to eliminate mistakes such as making a mistake in the wafer number.

[0015]

【Example】

[Embodiment 1] In this embodiment, the present invention is applied to SIMOX (Separ
ation by IMplanted OXygen) This is an example applied to a substrate.

The steps will be described below in order. [Step 1, FIG. 2] The lot number and the wafer number are numbered on the surface of the silicon substrate 21 by laser light.

A mask 22, such as a resist and a CVD insulating film, is formed on the entire surface. The mask 22 is patterned using light or an electron beam so that it remains only on the numbering section and the process monitor section.

[Step 2, FIG. 3] An oxygen ion beam is irradiated to implant oxygen ions into a portion of the silicon substrate 21 which is not covered with the mask 22 to form an oxygen ion implanted layer 23. The ion implantation conditions are, for example, an acceleration energy of 180 keV and a dose amount of 1 × 10 ¹⁸ cm ⁻² .

[Step 3, FIG. 3, FIG. 4] The mask 22 is removed. Annealed at 1300 ° C for 120 minutes, SI
Form a MOX substrate. At this time, the region into which the oxygen ions are implanted rises and the region 25 (the process monitor portion and the numbering portion) where the oxygen ions are not implanted are depressed, but there is no problem.

Through the above steps, the SIMO of this embodiment is
The X board is completed. In the following, an SOI device is formed by a normal process. In this embodiment, an example in which oxygen ions are ion-implanted into a silicon substrate to form a lower insulating film of SOI has been described.
A lower insulating film of I may be formed. Further, not only silicon but also compound semiconductor such as GaAs can be used.

[Embodiment 2] This embodiment is an example in which the present invention is applied to a bonded SOI substrate. The steps will be described below in order.

[Step 1, FIG. 5] The rear surface of the first silicon substrate 31 is numbered with a laser beam to identify a lot number and a wafer number.

After covering only the process monitor portion and the numbering portion with a silicon nitride film, a silicon oxide film 32 having a thickness of 2500 Å is formed by the LOCOS method, and the SOI film is formed.
Lower insulating film.

[Step 2, FIG. 6] The silicon oxide film 32 is polished until it becomes flat. Colloidal Amalphus silica base is used as the polishing agent, and a hard foam wet pad is used as the polishing cloth.

[Step 3, FIG. 7] The second silicon substrate 33 is attached to the surface of the first silicon substrate 31. [Step 4, FIG. 8] A groove 34 having a width of 0.5 μm and reaching the silicon oxide film 32a is formed in the second silicon substrate 33.

A 0.1 μm thick CVD oxide film is formed on the bottom of the groove 34 to serve as a stopper. [Step 5, FIG. 9] The second silicon substrate 33 is polished into a thin film. As the polishing agent, an amine-based aqueous solution mixed with colloidal silica is used.

[Step 6, FIG. 9, FIG. 10] After removing the stopper 35, lot number and wafer number are numbered on the surface of the second silicon substrate 33 by laser light. This is because the first silicon substrate 31
This is done because there is a possibility that the numbering on the back side of will disappear.

Through the above steps, the bonded SOI substrate of this embodiment is completed. The following is the SOI in the normal process
Form an element.

[0029]

According to the present invention, it is not necessary to flow a bulk substrate at the same time as an SOI substrate as a process monitor, so that TAT can be shortened and cost can be reduced.

Further, since the process monitor is provided on the SOI substrate, the process can be precisely controlled. Furthermore, since the numbering is not difficult to read, it is possible to reduce mistakes such as making a mistake in the wafer number.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a diagram showing a process 1 of Example 1.

FIG. 3 is a diagram showing a process 2 of Example 1.

FIG. 4 is a diagram showing a process 3 of Example 1.

FIG. 5 is a diagram showing a process 1 of Example 2.

FIG. 6 is a diagram showing a process 2 of Example 2.

FIG. 7 is a diagram showing a process 3 of Example 2.

FIG. 8 is a diagram showing a process 4 of Example 2.

FIG. 9 is a diagram showing a process 5 of Example 2.

FIG. 10 is a diagram showing a process 6 of Example 2.

[Explanation of symbols]

 11 SOI substrate 12 Process monitor section 13 Numbering section 14 Insulating film

Claims (3)

[Claims] 1. An SOI substrate used for forming a device in a semiconductor layer formed on an insulating film, comprising:
There is no insulating film below part or all of the process monitor part and the numbering part, and it is formed of a bulk semiconductor layer. A semiconductor device having an SOI structure having an insulating film below. 2. The method of manufacturing a semiconductor device according to claim 1, wherein a step of forming a mask pattern covering a part or all of the process monitor section on the surface of the semiconductor substrate and the numbering section, and oxygen on the entire surface. Alternatively, the method includes a step of implanting nitrogen ions, and a step of performing heat treatment to form an insulating film in a semiconductor substrate directly under a part or all of a process monitor portion and an element formation region other than a numbering portion. A method of manufacturing a semiconductor device, which is characterized. 3. The method of manufacturing a semiconductor device according to claim 1, wherein a part or all of the process monitor section on the surface of the first semiconductor substrate and an element forming region other than the numbering section are selectively oxidized. To form an oxide film, planarize the first semiconductor substrate, bond the second semiconductor substrate to the surface of the first semiconductor substrate, and thin the second semiconductor substrate. A method of manufacturing a semiconductor device, comprising: