JPH11111792A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a semiconductor device, wherein the particles attached on the surface of a semiconductor substrate in the manufacturing process of the semiconductor device are inspected with high reliability and high sensitivity, and the defects of the elements that are considered supposedly that the particles are the cause are prevented. SOLUTION: An epitaxial growing layer 2 of a silicon single crystal is formed on the surface of a silicon wafer 1, formed by a CZ method and a FZ method. Under a state wherein the surface is polished, the laser beam of a laser light source 11 is projected. A particle 3 is inspected by detecting the scattered light by light-receiving parts 12a-12d. A COP 4 at the surface of the silicon wafer 1 is eliminated by the epitaxial growing, and mis-detection of the particles can be prevented. By polishing the surface of the epitaxial growing layer 2 again, haze caused by the micro-roughness of the surface of the silicon wafer can be prevented. Furthermore, even when the laser light is projected in a direction of 90 deg. with respect to the surface of the silicon wafer 1, the particle 3 can be detected with high reliability. Furthermore, the optical intensity of the scattered light is enhanced, so that the detection sensitivity can be enhanced.

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 semiconductor device, and more particularly to a method for manufacturing a semiconductor device having a thickness of 0.1 .mu.m on a surface of a semiconductor substrate.
The present invention relates to a production method including a step of detecting fine particles of m or less.

[0002]

2. Description of the Related Art In a method of manufacturing a semiconductor device, if particles or the like adhere to the surface of a semiconductor substrate, element defects may be caused in a subsequent manufacturing process. For this reason, at the beginning of the manufacture of the semiconductor device, an inspection is performed to determine whether or not fine particles are attached to the surface of the semiconductor substrate. Conventionally, this type of inspection is performed on a silicon wafer composed of a silicon single crystal pulled up and grown by the CZ method or the FZ method, and fine particles attached on the surface are inspected by an inspection apparatus by laser light scattering. Had been detected. However, CZ
Has a distribution of 0.07 to 0.15 μm in size on the surface of a silicon wafer formed by the FZ method or the FZ method, and about several hundred COPs (Cristal
It is known that there is a rectangular concave defect called Originated Particle).

For this reason, when particles of 0.1 μm or less are detected by laser light scattering on such a silicon wafer, the particles adhering to the surface and the COP existing on the surface are detected without being separated. Would be.
Therefore, conventionally, in order to separate the fine particles of 0.1 μm or less from the COP, the incident angle of the laser beam incident on the surface of the silicon wafer is set to 90 ° with respect to the surface of the silicon wafer. The angle of incidence is changed from 10 ° to an oblique incident angle of 10 °, and a method of discriminating between the two using the difference in the state of the scattered light between the fine particles and the COP caused by this incident angle, that is, the fact that the scattered light is remarkable in the fine particles is adopted. ing.

[0004]

However, in this method, it is not guaranteed that the light intensity of the detected scattered light is entirely due to the fine particles, and it is difficult to detect the fine particles only by the scattered light. The reason is that the size of the COP on the silicon wafer surface is not constant, so
This is because even if the angle is changed to 0 °, diffuse reflection due to scattering cannot be completely suppressed, resulting in incomplete separation. Also, if the incident angle is 1
Even if it is about 0 °, as the particle diameter of the fine particles to be detected becomes smaller, CO scattered just below the surface of the silicon wafer
P may also be detected. The reason is that as the particle diameter of the fine particles becomes smaller, the intensity of the incident laser light must be increased, thereby increasing the transmittance of the incident laser light into the silicon wafer. Further, when the laser light is obliquely incident on the surface of the silicon wafer, the light intensity of the scattered light in the fine particles is weakened as a whole, causing a problem that the detection sensitivity is lowered.

An object of the present invention is to make it possible to detect fine particles of 0.1 μm or less adhering on the surface of a semiconductor substrate in a process of manufacturing a conductor device with high reliability without being confused with COP. An object of the present invention is to provide a method of manufacturing a semiconductor device including an inspection method.

[0006]

According to the present invention, there is provided a method of manufacturing a semiconductor device, which includes a step of inspecting fine particles adhering to the surface of a semiconductor substrate as part of the manufacturing process. After the epitaxial growth and polishing of the surface of the single crystal layer, the fine particle inspection step is performed. In this fine particle inspection step, a laser beam is projected from a direction substantially perpendicular to the surface of the single crystal layer grown on the semiconductor substrate, and scattered light of the laser light reflected on the surface of the single crystal layer is detected. Fine particles are detected based on the light intensity characteristics of the scattered light. in this case,
A method is employed in which laser light is projected onto the surface of the single crystal layer while being scanned, and fine particles are detected from scattered light at each projection position. Further, the scattered light is received by a plurality of light receiving units, and fine particles are detected from the light intensity distribution of the scattered light at each light receiving unit.

[0007] In the epitaxially grown single crystal layer, the COP on the surface of the semiconductor substrate is reduced by the hydrogen treatment usually performed during the epitaxial growth, so that the COP disappears on the surface of the epitaxially grown single crystal layer.
In addition, since the surface of the single crystal layer epitaxially grown is polished again, micro roughness of the surface is eliminated, and an obstruction factor called haze is also eliminated. On top of that, in order to inspect the fine particles by projecting a laser beam on the surface of the single crystal layer, CO 2
Confusion due to P and hindrance due to haze are also eliminated, and fine particles can be inspected with high reliability and high sensitivity.

[0008]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process sectional view for explaining the first embodiment of the present invention. First, FIG.
As shown in (a), the surface of a silicon wafer 1 made of a silicon single crystal pulled and grown by the CZ method or the FZ method is polished into a mirror surface. Thereafter, as shown in FIG. 1B, a process of growing an epitaxial growth layer 2 made of silicon single crystal on the surface of the silicon wafer 1 is performed, and the surface of the epitaxial growth layer 2 is polished again. Then, as shown in FIG.
The laser light 14 emitted from the laser light source 11 is projected onto the surface of the silicon wafer 1 whose surface has been polished, and the reflected light is detected by the light receiving unit 12, whereby the fine particles 3 adhering to the surface are removed. Perform inspection. In the silicon wafer 1, the COP 4 existing on the surface of the silicon wafer before the epitaxial growth is reduced by the hydrogen treatment usually performed during the epitaxial growth by the above-described epitaxial growth, and almost completely disappears on the surface of the epitaxial growth layer 2. Furthermore, not only the epitaxial growth but also the polishing of the surface eliminates the micro-roughness peculiar to the epitaxial growth surface, thereby preventing a hindrance, which is a hindrance in detecting fine particles.

Then, the silicon wafer is inspected for fine particles by the inspection apparatus shown in FIG. The inspection apparatus includes a laser light source 11 for projecting a laser beam from a direction of 90 ° to a surface of a mounting table 10 on which a silicon wafer 1 to be inspected is mounted, A plurality of light receiving portions for detecting laser light other than being regularly reflected toward the laser light projecting portion while the projected laser light is reflected on the surface of the silicon wafer while being directed in an inclined direction other than °. Parts 12a to 12d. The light receiving units 12a to 12d may detect the reflection intensity of the laser light in different directions by moving one or several light receiving units. The light receiving unit is connected to a processing unit 13 for inputting the light intensity of the laser beam received by each light receiving unit and performing a predetermined calculation process.

In such an inspection apparatus, when inspecting the silicon wafer 1 for fine particles, FIG.
After the silicon wafer 1 on which the epitaxial growth layer 2 has been formed in the step (1), is mounted on the mounting table 10 of the inspection apparatus shown in FIG. 2, and as shown in FIG. Laser light 14 is incident on the surface from a direction of 90 °. At this time, the laser beam is moved relative to the silicon wafer 1 so that the projection is performed while scanning the laser beam over almost the entire surface of the silicon wafer 1. Then, the reflected light is detected by each of the light receiving sections 12a to 12d. At this time, since each of the light receiving units 12a to 12d is arranged at a position inclined with respect to the surface of the silicon wafer 1,
In a to 12d, diffusely reflected scattered light other than the regular reflected light of the laser light is received.

Therefore, as shown in FIG. 3, when the fine particles 3 exist on the surface of the silicon wafer 1, the laser light 14
Are scattered by the fine particles 3, and therefore, the light receiving portions 12a-1
Light is received at a relatively high light intensity in many of the 2d, and a predetermined calculation process is executed in the processing unit 13 based on the distribution of the light intensity of the scattered light detected by these light receiving units 12a to 12d. Accordingly, the light scattering state on the surface of the silicon wafer 1 is recognized, and the presence of the fine particles 3 is detected from the scattering state. At this time, since the laser beam 14 is incident on the surface of the silicon wafer from the direction of 90 °, the light of the scattered light falling on the convex fine particles 3 is smaller than the case where the laser beam is incident at an angle of about 10 °. A silicon wafer 1 on which the strength is promoted and on which an epitaxial growth layer 2 is grown
Since the COP has completely disappeared on the surface of the substrate, erroneous detection due to this can be avoided, and the capture rate of fine particles of 0.1 μm or less is 9%.
It can be detected with high reliability of 5% or more and high sensitivity.

Therefore, after inspecting the fine particles, a normal semiconductor device manufacturing process is performed on a high-quality silicon wafer satisfying a predetermined condition, so that element defects caused by the fine particles are eliminated. It is possible to manufacture a highly reliable semiconductor device that does not occur. In the case of a silicon wafer having remarkable fine particles and not satisfying a predetermined condition, the reliability can be improved by repeating the epitaxial growth and the polishing.

[0013]

As described above, according to the present invention, since a silicon single crystal is formed on the surface of a silicon wafer by epitaxial growth and the fine particles are inspected while the surface is polished, the COP on the surface of the silicon wafer can be reduced. It is possible to prevent misdetection as fine particles by eliminating
The following fine particles can be detected with a highly sensitive detection rate of 95%. Further, by re-polishing the surface of the epitaxially grown silicon single crystal, haze caused by micro-roughness on the surface of the silicon wafer can be prevented. Further, even when the laser beam is projected from the direction of 90 ° to the surface of the silicon wafer, the fine particles can be detected with high reliability, so that the light intensity of the scattered light can be increased to increase the detection sensitivity.

[Brief description of the drawings]

FIG. 1 is a view for explaining a processing step of a silicon wafer for performing a particle inspection in a manufacturing method of the present invention.

FIG. 2 is a schematic configuration diagram of an inspection device for performing a particle inspection in the manufacturing method of the present invention.

FIG. 3 is a schematic diagram showing an inspection state of fine particles on a surface of a silicon wafer.

[Description of Signs] 1 silicon wafer 2 epitaxial growth layer 3 fine particles 4 COP 10 mounting table 11 laser light sources 12a to 12d light receiving unit 13 processing unit 14 laser light

Claims (5)

[Claims] 1. A method for manufacturing a semiconductor device, comprising a step of inspecting fine particles adhering to a surface of a semiconductor substrate as a part of a manufacturing process, wherein a single crystal layer is epitaxially grown on the surface of the semiconductor substrate, and A method of manufacturing a semiconductor device, wherein the fine particle inspection step is performed after polishing the surface of the semiconductor device. 2. The method according to claim 1, wherein the step of inspecting the fine particles includes projecting laser light from a direction substantially perpendicular to the surface of the single crystal layer grown on the semiconductor substrate, and scattering the laser light reflected on the surface of the single crystal layer. 2. The method for manufacturing a semiconductor device according to claim 1, wherein light is detected, and fine particles are detected based on a light intensity characteristic of the scattered light. 3. The method of manufacturing a semiconductor device according to claim 2, wherein the laser beam is projected onto the surface of the single-crystal layer while scanning, and fine particles are detected from scattered light at each projection position. 4. The method of manufacturing a semiconductor device according to claim 3, wherein the scattered light is received by a plurality of light receiving portions, and fine particles are detected from a light intensity distribution of the scattered light at each light receiving portion. 5. The semiconductor substrate is composed of a silicon wafer formed by CZ (Czochralski method) or FZ (floating zone method), and the surface of the silicon wafer is polished and a silicon single crystal is formed. 5. The method of manufacturing a semiconductor device according to claim 1, wherein the semiconductor device is epitaxially grown and its surface is polished again.