JPH09260447A - Particle monitor-oriented silicon single-crystal wafer, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of a particle monitor-oriented silicon wafer with a small number of COPs-(crystal-originated particle). SOLUTION: A particle monitor-oriented silicon single-crystal wafer made of silicon single crystal with a P-type crystal specific resistance not higher than 0.02 Ωcm ([B] is not lower than 3.32×10<18> atoms/cm<3> ) which is pulled through Czochralski method. By cutting the silicon single crystal pulled through Czochralski method to polish it in a mirror finishing way, a particle monitor- oriented silicon single-crystal wafer is manufactured. In this case, as silicon single crystal, the one with a P-type crystal specific resistance not higher than 0.02Ωcm ([B] is not lower than 3.32×10<18> atoms/cm<3> ) is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silicon single crystal wafer for particle monitors and a method for manufacturing the same.

[0002]

2. Description of the Related Art If particles adhere to a silicon single crystal wafer used for a semiconductor device (hereinafter abbreviated as a silicon wafer), a pattern break or the like will occur during the manufacture of the semiconductor device. In general semiconductor devices, particles with a particle size of 0.12 μm or more poses a problem.
Since the pattern width of M) is very fine as 0.3 μm, the grain size is 0.1 μm when forming such a pattern.
The presence of such particles also causes abnormalities such as pattern breakage, resulting in a significant reduction in yield during device manufacturing. Therefore, particles attached to the silicon wafer should be reduced as much as possible.

Therefore, in the silicon wafer manufacturing process, a particle counter is used to measure the number of particles on the silicon wafer for particle monitoring, whereby strict control of particles (examination of generation source, check of cleaning effect, Clean room level control, final product pre-shipment inspection, etc.) are performed. The measurement method of this particle counter is, for example, irradiating a wafer with a laser spot of about 10 to 100 μm, and the weak scattered light due to particles on the surface of the wafer is effectively collected by a large number of optical fibers or integrating spheres. The element converts it into an electrical signal. Therefore, the particle counter counts the number of points (bright spots) where light is scattered on the wafer surface.

By the way, a silicon wafer for a particle monitor is manufactured by processing from a silicon single crystal, that is, by cutting a silicon single crystal and mirror-polishing it. When growing a silicon single crystal, the silicon single crystal is grown. Since fine crystal defects are generated in the crystal and do not disappear during the crystal cooling, they remain as they are in the silicon wafer processed and manufactured from the silicon single crystal. Before using this wafer as a silicon wafer for particle monitoring, SC-1 cleaning for removing particles [mixed solution of ammonia water and hydrogen peroxide solution (NH ₄ O
Washing with H: H ₂ O ₂ : H ₂ O = 1: 1: 5). By this cleaning, organic substances and particles on the silicon wafer are removed, but the particle removal capacity is particularly high.
Then, since the crystal defect portion has a higher etching rate, pits are formed on the surface of the wafer.

When the number of particles on such a silicon wafer is measured by the particle counter, not only the true particles adhering to the surface of the wafer but also the light scattering due to the pits are detected, and the true number of particles is determined. There is a problem that it is not required. In addition,
In order to distinguish such pits from true particles,
It is called COP (Crystal Originated Particle).
In particular, a wafer processed and manufactured from a silicon single crystal manufactured by the Czochralski method (CZ method) is a wafer processed and manufactured from a silicon single crystal manufactured by the floating zone melting method (FZ method) and a Czochral It is known that the COP is remarkably higher than that of an epitaxial wafer obtained by growing a silicon single crystal thin film on a wafer processed and manufactured from a silicon single crystal pulled by the ski method.

The COP of a wafer processed and manufactured from a silicon single crystal manufactured by the Czochralski method extremely lowers the crystal growth rate (crystal pulling rate) when the silicon single crystal is pulled by the Czochralski method (for example, It is known that when it is set to 0.4 mm / min or less), it is remarkably reduced (see, for example, JP-A-2-267195). However, the crystal growth rate is usually 1 mm /
Although the COP of the wafer is remarkably reduced when it is reduced from 0.4 minutes / min to 0.4 mm / min or less, the productivity of the silicon single crystal is reduced to less than half. Wafer productivity will also be very low, significantly increasing its cost.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to improve the productivity of a silicon wafer for a particle monitor having a small COP.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have found that the above object is to increase the concentration of a dopant, particularly boron, introduced into a silicon melt so that the crystal resistivity of a silicon single crystal to be pulled is P-type, 0. 0.02 Ωcm or less ([B] = 3.32)
X10 ¹⁸ atoms / cm ³ or more), even if a silicon single crystal is pulled at a normal speed, i) SC-1 is applied to a wafer processed and manufactured from a silicon single crystal having a crystal resistivity of 0.02 Ωcm or less. The etching rate of crystal defects during cleaning is low, and as a result,
Pit becomes difficult to be formed, and the size of the generated pit becomes smaller, which makes it difficult to detect with a particle counter. Ii) When pulling a silicon single crystal having a crystal resistivity of 0.02 Ωcm or less, It is thought that the generation of crystal defects in crystals is suppressed (W.Wijaranakulaand S.Ar
cher, Appl. Phys. Lett. 65, 2069, 1994), it was found that the productivity of a silicon wafer for a particle monitor having a small COP can be improved.

Therefore, according to the present invention, the crystal resistivity of the P type is 0.02 Ωc, which is pulled up by the Czochralski method.
m or less ([B] = 3.32 × 10 ¹⁸ atoms / cm ³
The silicon single crystal wafer for particle monitor made of the above silicon single crystal and the silicon single crystal pulled by the Czochralski method are cut and mirror-polished to manufacture a silicon single crystal wafer for particle monitor. In the method, the silicon single crystal has a P-type crystal resistivity of 0.02 Ωcm or less ([B] = 3.32 × 10 ¹⁸ atoms / cm ³ or more).
The gist is a method for manufacturing a silicon single crystal wafer for particle monitors, which is characterized in that

In the present invention, the crystal resistivity of the silicon single crystal is 0.008 Ωcm or less ([B] = 1.13 × 1).
0 ¹⁹ atoms / cm ³ or more), the microroughness on the wafer surface after SC-1 cleaning of the wafer processed and manufactured from the silicon single crystal is deteriorated, and the grain size is 0.10 μm or more and less than 0.12 μm. Due to the significant increase in particle counts, state-of-the-art devices (64
As a silicon wafer for a particle monitor used in a manufacturing process of a silicon wafer used for MDRAM), the crystal resistivity of a silicon single crystal is P type, 0.02.
Ωcm or less ([B] = 3.32 × 10 ¹⁸ atoms / c
m ³ or more), greater than 0.008 Ωcm ([B] = 1.1
Those of less than 3 × 10 ¹⁹ atoms / cm ³ ) are suitable.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to examples.

[0012]

[Example] By the Czochralski method, a silicon melt in an 18-inch φ crucible was doped with boron at various concentrations to obtain four types of silicon single crystals having a 6-inch φ diameter and different crystal resistivities. It was pulled up at a crystal growth rate of 1 mm / min. Each of the four pulled silicon single crystals was cut and mirror-polished to obtain three silicon wafers from each silicon single crystal.

A liquid composition of these wafers was NH ₄ O.
Washing was carried out for 12 minutes with an SC-1 cleaning solution of H: H ₂ O ₂ : H ₂ O = 1: 1: 5 while maintaining the solution temperature at 77 ° C.
After that, with a particle counter [LS-6030 (manufactured by Hitachi Electronics Engineering)],
Particle size 0.10μm or more and less than 0.12μm, 0.12μ
m or more and less than 0.16 μm, 0.16 μm or more and 0.20 μ
The number of particles less than m and 0.20 μm or more was counted.

The results are shown in FIG. In the figure, the number in parentheses next to the crystal resistivity is the haze index, and the larger the number, the larger the microroughness. From Fig. 1, the crystal resistivity is 0.03Ωcm or more and 1Ωc.
A silicon wafer obtained from a silicon single crystal having a crystal resistivity of 0.01 Ωcm as compared with a silicon wafer obtained from a silicon single crystal of less than m ((A) and (B) in the figure) ((C) in the figure) ) Has a particle size of 0.1
It can be seen that the particle count number of 2 μm or more and less than 0.16 μm is as small as about 10, and the COP of such a size is remarkably reduced. This result shows that even when SC-1 cleaning is performed on a wafer processed and manufactured from a silicon single crystal having such a low crystal resistivity, few pits are formed, and only smaller pits are formed. It is considered that this is because there are originally few crystal defects in the pulled silicon single crystal.

Further, the crystal resistivity is 0.008 Ωcm,
The silicon wafer obtained from the silicon single crystal of 0.007 Ωcm ((D) in the figure) is the same as the silicon wafer obtained from the silicon single crystal of 0.01 Ωcm ((C) in the figure). , Particle size is 0.12μm
The number of particle counts above 0.16 μm is 10
Although it is extremely small, around 0.1 μm or more, it is 0.10 μm or more due to deterioration of microroughness on the wafer surface.
Since the particle count number of less than 12 μm is remarkably increased, the silicon wafer obtained from the silicon single crystal having a crystal resistivity of 0.008 Ωcm or less has a particle number of 0.10 μm or more and less than 0.12 μm. It turns out to be unsuitable for counting.

[0016]

According to the present invention, a silicon wafer suitable for a particle monitor silicon wafer having a COP of 0.12 μm or more and a significantly small COP is manufactured from a silicon single crystal pulled at a conventional crystal growth rate. Therefore, the productivity of the silicon single crystal wafer for particle monitor can be significantly improved and the cost thereof can be reduced.

[Brief description of drawings]

1 is a graph showing particle counts on silicon wafers manufactured and processed from silicon single crystals having various crystal resistivities containing boron as a dopant; (A) When the crystal resistivities are about 1 Ωcm, (B) When the crystal resistivity is 0.03 or 0.04 Ωcm, (C)
When the crystal resistivity is 0.01 Ωcm, (D) when the crystal resistivity is 0.008 and 0.007 Ωcm.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01L 21/02 H01L 21/208 P 21/208 G01N 1/28 G (72) Inventor Masanori Kimura Gunma 2-13-1, Isobe, Annaka Prefecture, Japan Shin-Etsu Semiconductor Co., Ltd., Semiconductor Isobe Laboratory (72) Inventor Hirotoshi Yamagishi 2-13-1, Isobe, Annaka-shi, Gunma Shin-Etsu Semiconductor Co., Ltd.

Claims (4)

[Claims] 1. A silicon single crystal wafer for particle monitoring, which is pulled by the Czochralski method and is made of a silicon single crystal having a P-type crystal resistivity of 0.02 Ωcm or less. 2. The crystal resistivity, which is pulled up by the Czochralski method, is P-type and is 0.02 Ωcm or less and 0.
A silicon single crystal wafer for particle monitor, which is made of a silicon single crystal having a size larger than 008 Ωcm. 3. A method for producing a silicon single crystal wafer for particle monitor by cutting a silicon single crystal pulled by the Czochralski method and mirror-polishing it, wherein the silicon single crystal has a P-type crystal resistivity. , 0.02 Ωcm or less is used, and a method for producing a silicon single crystal wafer for particle monitoring, characterized in that: 4. A method for producing a silicon single crystal wafer for particle monitors by cutting a silicon single crystal pulled by the Czochralski method and mirror-polishing it, wherein the silicon single crystal has a P-type crystal resistivity. , 0.02 Ωcm or less and 0.008 Ωc
A method of manufacturing a silicon single crystal wafer for particle monitoring, characterized in that a wafer having a size larger than m is used.