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Polishing Composition and Polishing Method

a composition and polishing technology, applied in the field of polishing composition and polishing method, can solve the problems of long polishing time, high polishing capability, and difficulty in a conventional method to polish the single crystal si plane at a high removal ra

Inactive Publication Date: 2008-12-11
FUJIMI INCORPORATED
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a polishing composition and method for polishing silicon carbide objects. The composition includes abrasive grains and an iodine compound with a pH of 6 or more for polishing the Si plane, or with a pH of 8 or less for polishing the C plane. The composition can also be used to polish both the Si and C planes singularly with a pH of 6 to 8. The polishing method involves preparing the object with the polishing composition and then polishing it using the prepared composition. The technical effects of the invention include improved polishing efficiency and reduced damage to the silicon carbide object.

Problems solved by technology

This composition, however, involves problems resulting from needing a very long polishing time, because of its poor capability of polishing crystal planes.
Therefore, it is difficult for a conventional method to polish the single crystal Si plane at a high removal rate.
Moreover, the polishing composition disclosed by the above patent publication also involves problems of easily causing surface defects, e.g., pit, when applied to the C [000-1] plane of single crystal 4H-SiC or 6H-SiC substrate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[0012]The polishing composition of the first embodiment is produced by incorporating colloidal silica with a given quantity of iodate or periodate, and, as required, diluting the resulting mixture with water. It is therefore essentially composed of colloidal silica working as abrasive grains, iodate or periodate as an iodine compound and water.

[0013]The polishing composition of the second embodiment is produced by incorporating colloidal silica with a given quantity of iodic or periodic acid and an alkali, and, as required, diluting the resulting mixture with water. It is therefore essentially composed of colloidal silica working as abrasive grains, an iodic or periodic acid as an iodine compound, alkali as a pH adjuster and water. In other words, the polishing composition of the second embodiment differs from that of the first embodiment in that it contains an iodic or periodic acid as an iodine compound in place of iodate or periodate, and an alkali.

[0014]The polishing composition...

second embodiment

[0018]The iodine compound incorporated in the polishing composition of the second embodiment to improve its removal rate may be an iodic or periodic acid, preferably the latter, more preferably orthoperiodic acid (H5IO6). A periodic acid is preferable to an iodic acid, because of its higher redox potential and higher oxidizing power.

[0019]Orthoperiodic acid is preferable to any other periodic acid, because of its wider availability.

[0020]Each of the polishing compositions of the first and second embodiments may fail to polish the Si [0001] plane at sufficiently high removal rate when it contains an iodine compound at below 0.1 g / L, or more specifically below 0.5 g / L, or even more specifically below 1 g / L. Therefore, it preferably contains an iodine compound at 0.1 g / L or more, more preferably 0.5 g / L or more, most preferably 1 g / L or more, in order to achieve a higher removal rate. On the other hand, when each of the polishing compositions of the first and second embodiments contain...

third embodiment

[0038]Next, the present invention will be described.

[0039]The polishing composition of the third embodiment is produced by incorporating colloidal silica sol with a given quantity of an iodine compound and, as required, diluting the resulting mixture with water. It is therefore essentially composed of colloidal silica working as abrasive grains, an iodine compound and water. The polishing composition of the third embodiment is used for polishing a single crystal 4H-SiC or 6H-SiC substrate, more specifically the C [000-1] plane of a single crystal 4H-SiC or 6H-SiC substrate.

[0040]The polishing composition of the third embodiment may fail to exhibit a sufficient polishing capability when it contains colloidal silica at below 0.05% by mass, or more specifically below 0.1% by mass, or even more specifically below 1% by mass. Therefore, it preferably contains colloidal silica at 0.05% by mass or more, more preferably 0.1% by mass or more, most preferably 1% by mass or more, in order to a...

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Abstract

A first polishing composition includes abrasive grains and an iodine compound and has a pH of 6 or more. The first polishing composition can suitably polish the Si [0001] plane of a single crystal silicon carbide substrate. A second polishing composition includes an iodine compound and has a pH of 8 or less. The second polishing composition can suitably polish the C [000-1] plane of a single crystal silicon carbide substrate. A third polishing composition includes abrasive grains and an iodine compound and has a pH of 6 to 8, inclusive. The third polishing composition can suitably polish each of the Si [0001] and C [000-1] planes of a single crystal silicon carbide substrate.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a polishing composition for use in polishing an object formed of single crystal semiconductor, in particular an object formed of single crystal silicon carbide, such as a substrate of single crystal hexagonal silicon carbide, and the polishing method using the polishing composition.[0002]A substrate of single crystal silicon carbide, such as a single crystal 4H-SiC or 6H-SiC substrate is normally polished by a preliminary step for polishing the substrate surface with a slurry containing abrasive grains of diamond, and finishing step for polishing the preliminarily polished surface. The finishing step removes an amorphous polishing-modified layer developing on the substrate surface in the preliminary step and, at the same time, flattens the exposed surface into a crystal plane as a result of removal of the polishing-modified layer. A polishing composition containing colloidal silica and used at a pH of 7 to 10, disclos...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B24B1/00B24B29/00
CPCC09G1/02C09K3/1463C09K3/14
Inventor KAWATA, KENJIHOTTA, KAZUTOSHI
Owner FUJIMI INCORPORATED
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