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Preparation Method of Particle Contamination Wafer

IP.com Disclosure Number: IPCOM000197289D
Publication Date: 2010-Jul-01
Document File: 6 page(s) / 299K

Publishing Venue

The IP.com Prior Art Database

Related People

Masashi Uchibe: AUTHOR [+3]

Abstract

For particle removal tests, particle contamination wafers prepared by dipping method is usually used. One of the most popular particles for the intentional contamination is silicon nitride. The traditional dipping method has the following problems: 1. No preferable large size particles adhere on the wafer because of aggregation of the particles. 2. Particles adhere inhomogeneously on wafer surface. 3. The number of adhered particles strongly varies between wafers in the same prepa-ration batch as well as between different batches. Whole process of silicon nitride particle dispersion to the liquid is performed in acidic solution such as diluted HCl of < pH 4. By this method, we can solve all problems above.

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Page 1 of 6

Preparation Method of Particle Contamination Wafer

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Masashi Uchibe, Teruo Haibara and Yoshihiro Mori

内部 眞佐志 榛原 照男 森 良弘

Siltronic Japan Corporation

シルトロニック・ジャパン株式会社

Summary

Background

    For particle removal tests, particle contamination wafers prepared by dipping method is usually used. One of the most popular particles for the intentional contami- nation is silicon nitride.

The traditional dipping method has the following problems:
1. No preferable large size particles adhere on the wafer because of aggregation of the particles.

2. Particles adhere inhomogeneously on wafer surface.
3. The number of adhered particles strongly varies between wafers in the same preparation batch as well as between different batches.

This method

Whole process of silicon nitride particle dispersion to the liquid is performed in acidic solution such as diluted HCl of < pH 4. By this method, we can solve all problems above.

の作成方法作成方法作成方法

作成方法

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Page 2 of 6

About intentional particle contamination

For particle removal tests, we use particle contamination wafer. One of the most popular particle materials for such tests is silicon nitride.

Problem of previous method

4000

3000

pcs

2000

1000

0

0.10-

0.11

0.11-

0.12

0.12-

0.13

0.13-

0.14

0.14-

0.15

0.15-

0.20

0.20-

0.30

0.30-

LPD Size(um)

Adhesion of larger particles (agglomerated?)

Particles inhomogeneously adhere on surface.

Total LPD (Dispersion process in DIW )

Data overflow

25000

20000

Total LPD[pcs]

15000

10000

5000

0

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 Si3N4[m g]

The number of adhered particle is not stable.

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Page 3 of 6

Target of this investigation

Selective adhesion of smaller particles (< 0.15 µm)

Uniform adhesion on the surface

Reproducible adhesion between different preparation batches as well as in each single batch

The production procedure of particle contamination wafer

To be improved in this method

Silicon nitride par- ticles

Disperse sili- con nitride particles with ultrasonic

Pour into large tank with acidic solution

Wafers are dipped into the tank

to adhere silicon nitride particles

on the surfaces.

Rinse with DIW

Spin dry

Process of this method

Previous method

This method

Silicon nitride par- ticles

Ultrasonic irradiation

Silicon nitride par- ticles

DIW

DiluteHCl

Dilute HCl

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Page 4 of 6

Mechanism

This method :

In acidic solution, silicon nitride particles are positively charged.

Previous method :

In DIW (neutrality), silicon nitride particles are not charged.

+

+

dispersion

agglomeration

Results of this paper 1

Improved particle size distribution

By using this...