JPH0472727A - Gas cleaning process - Google Patents

Abstract

PURPOSE:To obtain a novel cleaning process in high productivity producing no pollutants by a method wherein semiconductor wafers are arranged in a vessel made of quartz, ceramic etc., and then HCl gas, HF gas or ozone gas, steam, etc., are led into the vessel to expose the wafers to these gasses. CONSTITUTION:When Si wafers are arranged in a quartz boat inside a quartz vessel and after leading HCl gas into the vessel and simultaneously reducing the pressure to the level at about 0.35Torr using a vacuum pump, the HCl gas leading step is stopped further to reduce the pressure, the heavy metallic chloride adhering to the surface of the Si wafers is vaporized to be cleaned up. At this time, the heating at 500 deg.C may be allowable but Si can be etched away by heating the Si wafers at the temperature exceeding 1500 deg.C. Furthermore, not only HCl gas but also Cl2, gas, HF gas or the mixed gas of HCl gas and ozone gas or ammonia gas and ozone gas etc., may be applicable while the residual gas can be removed by using steam.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a new method for cleaning semiconductor wafers.

[Conventional technology]

Conventionally, a wet cleaning method has been most commonly used as a method for cleaning semiconductor wafers. In other words, it is customary to immerse a semiconductor wafer in a hydrofluoric acid solution, a hydrochloric acid solution, a nitric acid solution, a sulfuric acid solution, an ammonia solution, a hydrogen peroxide solution, or a mixture thereof. Methods such as immersion in pure water were used for removal.

[Problem that the invention seeks to solve]

However, according to the above-mentioned conventional technology, when cleaning a Si wafer with HF, for example, heavy metal ions dissolved in HF are
There have been problems such as problems such as insufficient cleaning, such as adhesion to the surface, which may result in contamination, and poor productivity as cleaning with pure water is always required in the subsequent process.

The present invention solves the problems of the prior art and solves the problems of the prior art.
The purpose is to provide a new cleaning method for semiconductor wafers, etc. that is free from contamination.

[Means to solve the problem]

In order to solve the above problems, the present invention relates to gas cleaning, in which a semiconductor wafer is placed in a container made of quartz or ceramic, and the container is filled with hydrochloric acid gas, hydrofluoric acid gas, ozone gas, water vapor, etc. The basic method is to introduce a gas and expose the semiconductor wafer to the atmosphere of the gas.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Taking as an example the case of hydrochloric acid (ACT) cleaning, which is used most often, a Si wafer mounted on a quartz boat is placed in a quartz container, and HOt gas from a Hat gas cylinder is introduced into the quartz container. 0.5 with vacuum pump
After maintaining the pressure at about 5 Torr, stop introducing HOt gas and secretly reduce the pressure to about 0.0001 Torr, the heavy metal chlorides that adhere to the Si wafer surface will be vaporized and cleaned. becomes. In the case of this example, it may be heated to about 500°C at most using an external heater (if heated above 1500°C, 81 will be etched. Furthermore, not only hot gas but also at.

Other gases such as gas, HF gas, a mixed gas of HOt gas and ozone gas, or a mixed gas of ammonia gas and ozone gas may be used.

In addition, using water vapor as the gas can remove residual gas at a rate equivalent to or better than pure water cleaning, and a mixed gas of hydrogen sulfide gas and water vapor has the same effect as sulfuric acid gas, and can remove nitrogen oxide gas and water vapor. The mixed gas has effects similar to those of nitric acid gas, and it goes without saying that gases such as H, O, and other gases may also be used in combination or in combination.

Further, the container may be made of ceramic other than quartz, such as slt or At2o8.

〔Effect of the invention〕

The present invention has the effect of providing a new cleaning method that is free from contamination and has good productivity for cleaning semiconductor wafers and the like.

Claims (1)

[Claims] The semiconductor wafer is placed in a container made of quartz or ceramic, and a gas such as hydrochloric acid gas, hydrofluoric acid gas, ozone gas, or water vapor is introduced into the container to clean the surface of the semiconductor wafer. Gas cleaning method.