Etching method and apparatus
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorKiyoyuki Morita
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Abstract
A subcritical or supercritical water is used to selectively etch a silicon nitride film against a silicon dioxide film or to selectively etch a silicon dioxide film against a crystalline silicon region. This method is applicable to a process of forming a MISFET or a charge emitting device.
Claims7
A method for etching a target layer of an object being processed, and at least a part of the target layer is covered by another substance, the method comprising the steps of:
- heating and pressuring a fluid under such conditions that the fluid is a liquid;
- and
- exposing the target layer to the fluid while respectively and independently controlling the humidity surrounding the object and the pressure of the fluid, and allowing a substance in the fluid to react with a part of the target layer that is not covered by the other substance, thereby etching away at least a part of the target layer and substantialy retaining the other substance.
The method of claim l, wherein the fluid is a water, and
- wherein the target layer is exposed to the water, which is a roughly subcritical liquid, when the target layer is etched.
A method for etching a target layer of an object being processed, the method comprising the steps of:
- heating an pressuring a fluid under such conditions that the fluid is a liquid;
- and
- exposing the target layer to the fluid while respectively and independently controlling the humidity surrounding the object and the pressure of the fluid, and allowing a substance in the fluid to react with the target layer, thereby etching away the target layer,
- wherein the fluid is water and the target layer is a silicon nitride film,
- wherein the target layer is exposed to the water, which is a roughly subcritical liquid, when the target layer is etched and the water is heated to a temperature between 150° C. and 315° C. and pressured to a vapor pressure or higher.
Dependencies are inferred from the claim text.