Patent ID: 8679354
Filing Date: 2014-03-25
Classification: B81C

Abstract:
1. A method of releasing, in an etch process, a microstructure comprising a silicon oxide layer located between a substrate layer and a layer to be released from the silicon oxide layer, the method comprising; exposing the silicon oxide layer to a hydrogen fluoride vapour in a process chamber, thereby forming a primary source of water and a condensed fluid layer on the silicon oxide layer; adding water vapour to the process chamber as a secondary source of water, in order to maintain a depth of at least 10 Å of the condensed fluid layer, wherein the water content of the condensed fluid layer is predominantly from the primary water source and not the secondary water source; and controlling one or more of a partial pressure of the hydrogen fluoride vapour, a partial pressure of water vapour, or a chamber pressure such that the condensed fluid layer is substantially confined to exposed surfaces of the silicon oxide layer, with substantially no condensed fluid layer produced at unwanted sites within the microstructure, including exposed surfaces of the substrate layer and the layer to be released from the silicon oxide layer; wherein a supply of water vapour to the process chamber is controlled independently of the supply of hydrogen fluoride vapour to the process chamber.