Method for forming a through silicon via (tsv)

A method of forming a through silicon via (TSV), the method comprising:

• forming a hard mask over a semiconductor substrate;
• forming a via opening in the semiconductor substrate using the hard mask, wherein:
• the via opening comprises a bottom and sidewalls;
• and
• a polymer comprising silicon, carbon, and fluorine is formed along at least a portion of the bottom of the via opening;
• performing a wet clean to remove a first portion of the polymer and form a first carbon containing oxide along portions of the sidewalls by pulling silicon and carbon from the substrate;
• performing an ash process to remove a second portion of the polymer;
• performing a wet process to remove a third portion of the polymer;
• and
• repeating the steps of performing an ash process and performing a wet process a predetermined number of times;
• forming an oxide along the sidewalls and bottom of the opening;
• forming an adhesion layer and a conductive fill in the via opening;
• and
• removing a portion of the semiconductor substrate.

A method of forming a through silicon via (TSV), the method comprising:

• forming a hard mask over a semiconductor substrate;
• forming a via opening in the semiconductor substrate using the hard mask, wherein:
• the via opening comprises a bottom and sidewalls;
• and
• a polymer comprising silicon, carbon, and fluorine is formed along at least a portion of the bottom of the via opening;
• performing a first wet clean using piranha, hydrofluoric acid and ammonium hydroxide to remove a first portion of the polymer and form a first carbon containing oxide along portions of the sidewalls by pulling silicon and carbon from the substrate;
• performing a first ash process to modify the first carbon containing oxide and to remove a second portion of the polymers;
• performing a first wet etch process using dilute hydrofluoric acid to remove the modified first carbon containing oxide and a third portion of the polymer;
• performing a second ash process to form a second carbon containing oxide along at least a portion of the sidewalls by pulling silicon and carbon from the semiconductor substrate;
• performing a second wet etch process using dilute hydrofluoric acid to remove the second carbon containing oxide and a fourth portions of the polymer;
• performing a third ash process to form a third carbon containing oxide along portions of the sidewalls by pulling silicon and carbon from the substrate and removing any remaining portions of the polymer;
• performing a second wet clean piranha, hydrofluoric acid and ammonium hydroxide to remove the third carbon containing oxide and form a chemical oxide along the sidewalls and bottom of the via opening;
• forming an adhesion layer and a conductive fill in the via opening;
• and
• removing a portion of the semiconductor substrate.