Selective Etching of Hafnium Oxide Using Non-Aqueous Solutions

A method for processing semiconductor substrates, the method comprising:

• providing a semiconductor substrate comprising a first structure and a second structure, the first structure comprising hafnium oxide, the second structure comprising silicon oxide;
• exposing the semiconductor substrate to an etching solution comprising hydrofluoric acid and ethylene glycol, the etching solution maintained at a temperature of 25° C. to 60° C.,
• wherein a concentration of ethylene glycol in the etching solution is at least 95% by volume;
• and
• partially etching the first structure,
• wherein an etching rate of the first structure is at least twice greater than an etching rate of the second structure and is at least 50 Angstroms per minute.

A method for processing semiconductor substrates, the method comprising:

• providing a semiconductor substrate comprising a first structure and a second structure,
• the first structure comprising hafnium oxide,
• the second structure comprising polysilicon;
• exposing the semiconductor substrate to an etching solution comprising hydrofluoric acid, water, and ethylene glycol,
• wherein a concentration of ethylene glycol in the etching solution is at least 90% by volume and concentration of water in the etching solution is less than 4% by volume;
• and
• etching the first structure,
• wherein an etching rate of the first structure is at least twenty times greater than an etching rate of the second structure.