Method for forming micro-electro-mechanical system (MEMS) device structure

A method for forming a micro-electro-mechanical system (MEMS) device structure, comprising:

• forming an electrode over a substrate;
• forming a cavity over the electrode;
• forming a MEMS substrate over the substrate, wherein the cavity is formed between the first substrate and the MEMS substrate;
• and
• performing a dry etching process on the MEMS substrate to form a hole in the MEMS substrate, wherein the dry etching process comprises a plurality of etching cycles, each of the etching cycles comprising:
• performing a deposition step to form a protection layer on the opening;
• performing a stripping step to remove a portion of the protection layer;
• and
• performing an etching step to etch a portion of the MEMS substrate.

A method for forming a micro-electro-mechanical system (MEMS) device structure, comprising:

• forming an interconnect structure over a first substrate;
• forming an outgassing prevention layer over the interconnect structure;
• forming a cavity adjacent to the outgassing prevention layer;
• forming a MEMS substrate over the electrode, wherein the cavity is surrounded by the first substrate and the MEMS substrate;
• forming a hole through the MEMS substrate using a dry etching process;
• and
• performing a cleaning process on the hole after the dry etching process, wherein the cleaning process does not comprise a wet cleaning process.