The process of cleaning the chamber with hydrogen chloride gas

The process of cleaning the chamber with hydrogen chloride gas

In the process of epitaxial silicon wafer manufacturing, hydrogen chloride gas as an etching gas is effective for removing the accumulated by-products in the components and cleaning the chamber.

In epitaxial growth, by-products produced from the feedstock gas are accumulated in the chamber walls and components located inside the chamber. If the process of moving the wafer into the chamber, epitaxial growth and cleaning the chamber with hydrogen chloride gas after moving the wafer out of the chamber is repeated many times in the state where the by-product is placed, particles will be generated from the by-product and the quality of the epitaxial silicon wafer will be badly affected.

Therefore, it is necessary to remove the by-products accumulated in the components in the chamber after repeating the above cycle for a certain number of times. In order to remove the by-products, it has the following methods: heating the members in the chamber, and then using etching gas to remove the accumulated by-products in the cleaning process, and the members with accumulated by-products are removed to the outside of the chamber, and the etching method of removing the by-products through wet etching or dry etching.

The components with by-products removed can be used for epitaxial growth again. However, if the cleaning process and etching are repeated for many times, the quality of epitaxial silicon wafers will decrease, so the components need to be replaced. According to the accumulated film thickness, the components in the chamber should be determined whether to be replaced.

Therefore, it is judged that if the components in the chamber are changed according to the accumulated film thickness, the quality of epitaxial silicon wafers may decrease.

In order to solve the above problems, the investigation found that even if the cumulative film thickness of by-products is the same, the number of cleaning times after epitaxial growth may also affect the quality of epitaxial silicon wafers. During epitaxial growth, the components in the chamber have accumulated areas with by-products and less accumulated areas with by-products, and the areas with less accumulation of by-products are directly exposed to hydrogen chloride gas during cleaning. In particular, for components containing graphite base material covered by silicon carbide film, the higher the cleaning frequency, the more hydrogen chloride gas etched in the area with less by-product accumulation.

Moreover, if the residual film thickness through etching silicon carbide film decreases, the amount of graphite or metal in the base material through silicon carbide film increases, and the quality of epitaxial silicon wafer decreases. That is to say, even when the cumulative film thickness of by-products is the same, according to the cleaning frequency, the residual film thickness of silicon carbide film in the area without accumulation of by-products is different, so there is the risk of epitaxial silicon wafer quality degradation. Furthermore, if the results of further research focus on the cumulative supply of hydrogen chloride gas and the cumulative etching amount which are highly related to the residual film thickness of silicon carbide film, the replacement period of components such as the base can be correctly determined, and the results show that the risk of epitepitic silicon wafer quality degradation can be reduced.

Based on the above views, the main plan is as follows

(1) A manufacturing method for epitaxial silicon wafers, which includes the following steps: the silicon wafers are moved into the chamber of the epitaxial growth device; The raw material gas is supplied to the chamber so that the silicon epitaxial layer grows on the silicon wafer, and the silicon wafer is used as the epitaxial silicon wafer; Move the epitaxial silicon wafer outside the cavity; And after, the hydrogen chloride gas supply to the described in the cavity chamber interior of indoor cleaning, described in the epitaxial silicon wafer manufacturing method of characteristics is described in the cleansing, the accumulation of hydrogen chloride gas supply according to the stated, decide whether to replace Settings it is cavity indoor and includes the parent metal is covered by silicon carbide film of graphite artifacts.

(2) according to (1) the epitaxial silicon chip manufacturing method, among them, the epitaxial growth device has: hy pnotor, load the silicon chip; And a preheating ring is arranged on the outer circumference of the base through a specified gap; The member is more than one member selected from the base and the preheating ring.

(3) According to the manufacturing method of epitaxial silicon wafers described in (1) or (2), where, during the cleaning, the hydrogen chloride gas supply is measured, and after the cleaning, the replacement of the component is determined before the cumulative hydrogen chloride gas supply exceeds a specified threshold.

This is the role of hydrogen chloride gas in epitaxial silicon wafer manufacturing.