JP2002068765A - Method of recycling used quarts glass-made fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of easily recycling a quarts glass-made fixture used in a plasma generating apparatus. SOLUTION: This method of recycling the quarts glass-made fixture used in the plasma generating apparatus is characterized in that the quarts glass- made fixture is heated at a temperature of 500 deg.C or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for regenerating a quartz glass jig used in an apparatus for generating plasma.

[0002]

2. Description of the Related Art Conventionally, a plasma generator has been used for an etching process of a semiconductor element such as a silicon wafer, a thin film forming process, or the like. Processing container for
A window material for introducing high-frequency waves into the processing vessel, an RF power supply for irradiating the workpiece with ions and radicals generated in the plasma, a shield ring for confining the plasma in the processing vessel, a gas introduction circuit, etc. ing. And
As a material of a jig such as a window material and a shield ring, quartz glass is used because of its good electrical characteristics and high purity, and its plasma contact surface has irregularities. However, fluorine-based corrosive gas is often used in the etching of silicon wafers, particularly in the etching of oxide films, and when it is turned into plasma, F radicals are generated in the plasma, resulting in quartz glass windows. A jig such as a material or a shield ring is attacked, a concave and convex concave portion formed on the jig is locally etched, and microcracks existing there grow into large holes.
The growth of holes based on the microcracks can be prevented by forming irregularities by a chemical treatment without generation of microcracks.However, in the plasma, abnormally strong ultraviolet rays and electron beams are generated together with the ions and radicals. The Si—O bond of quartz glass is broken to generate defects, the density of the quartz glass surface is increased, the deterioration of quartz glass is promoted, particles are generated, and the object to be processed (silicon wafer, etc.) is secondary. Had the disadvantage of contamination. Therefore, it is necessary to replace the quartz glass jig in a short time, and the plasma processing cost of the semiconductor element is increased.

[0003]

In view of the current situation,
The present inventors have conducted intensive research and as a result, by heating a quartz glass jig having defects caused by abnormally strong ultraviolet rays or electron beams generated from plasma at a specific temperature or more,
The inventors have found that the defects can be repaired and reused, and the cost of plasma processing can be reduced, and the present invention has been completed. That is,

An object of the present invention is to provide a method for easily regenerating a quartz glass jig used in an apparatus in which plasma is generated.

[0005]

In order to achieve the above object, the present invention provides a method for regenerating a quartz glass jig used in an apparatus in which plasma is generated.
The present invention relates to a method for regenerating a quartz glass jig, wherein the jig is heated at a temperature of about 1000 ° C.

[0006] As a quartz glass jig used in a device where plasma is generated, a jig made of natural or synthetic quartz glass is used. Alternatively, irregularities are formed in order to prevent detachment of the attached matter. When this jig is used in a plasma generator, the ions and radicals generated in the plasma, particularly the abnormally strong ultraviolet rays and electron beams, cut the Si-O bonds of the quartz glass to generate defects,
Deterioration proceeds. The quartz glass jig with this defect
When heated at a temperature of 00 ° C to 1000 ° C, preferably 600 ° C or higher, more preferably 700 ° C or higher, defects are repaired,
The transmittance is also improved, and the quartz glass jig can be reused.
In particular, when the above-described heating is performed on a quartz glass jig having a portion where the transmittance of ultraviolet light having a wavelength of 300 nm or less becomes 50% or less, defects in quartz glass can be repaired, and the transmittance can be 80% or more. it can. The heating time may be shorter as the temperature increases, and is not particularly limited. The heating may be to raise the temperature in the processing container to the above range or to heat the inside of a heating furnace.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to specific examples. However, these examples are merely illustrative, and the present invention is not limited thereto.

[0008]

Example 1 A fluorine-based gas was introduced into a processing vessel of a plasma generator equipped with a quartz glass window material for introducing a high frequency, and plasma was generated to etch 7000 silicon wafers. When the window material after the treatment was measured by a polarizing plate strain meter, distortion was locally confirmed. When the quartz glass window material was heated in a heating furnace at 750 ° C. for 30 minutes, the distortion disappeared. The silicon wafer was etched using this window material again, but could be used without generating particles.

Example 2 10000 in the processing vessel of the plasma generator of Example 1.
When ultraviolet rays having a wavelength of 300 nm or less were irradiated to the quartz glass window material when the silicon wafers were plasma-etched, an E ′ center was confirmed at 215 nm, and the transmittance at that wavelength was 30%. The inside of the processing container was heated to 900 ° C. with the window material provided, and maintained for 30 minutes.
The transmittance at 215 nm of the window material after the treatment was restored to 85%. Using this window material again, one silicon wafer
0000 sheets were etched, but no problem occurred.

Comparative Example 1 The window material of Example 2 was heated in a heating furnace at 500 ° C. for 30 minutes, but the distortion did not disappear and the transmittance at a wavelength of 215 nm was 30.
%, There was no recovery of transmittance. When the silicon wafer was etched using this window material again, 10
Particles were generated after the processing of 00 sheets and could not be used.

[0011]

The recycling method of the present invention is a simple method of heating a used quartz glass jig at a temperature of 500 ° C. or more, can repair a defect based on plasma in quartz glass, and reuse the jig. Therefore, the cost of the plasma processing of the semiconductor element can be reduced.

Claims (2)

[Claims] 1. A method for regenerating a quartz glass jig used in an apparatus in which plasma is generated, wherein the quartz glass jig is used
A method for regenerating a quartz glass jig, wherein the jig is heated at a temperature of 00C to 1000C. 2. The quartz glass jig used has a wavelength of 300 nm.
The method for reclaiming a quartz glass jig according to claim 1, wherein the jig is formed with a portion having a transmittance of 50% or less of the following ultraviolet rays.