Dual bake for BARC fill without voids

A method of forming a semiconductor device comprising:

• forming a first layer over a semiconductor substrate;
• performing a first etch to form a plurality of holes through the first layer;
• forming a bottom anti-reflective coating (BARC) layer over the first layer and in the plurality of holes;
• heating the BARC layer to a flow temperature so that the BARC layer flows to fill any voids present in the plurality of holes;
• hardening the BARC layer after heating the BARC layer to a flow temperature;
• and
• performing a second etch to form a trench in the first layer and over the at least one hole, wherein the hardened BARC layer in the at least one hole acts as an etch resistant layer during the second etch.

A method of forming a semiconductor device comprising:

• forming a first layer over a semiconductor substrate;
• forming at least one hole through the first layer;
• forming a bottom anti-reflective coating (BARC) layer in the at least one hole;
• placing the semiconductor substrate in a heating chamber;
• performing a first heating within the heating chamber to heat the BARC layer to a flow temperature;
• performing a second heating within the heating chamber to heat the BARC layer to a hardening temperature so that the BARC layer hardens, wherein the hardening temperature is greater than the flow temperature, wherein the first heating and the second heating are performed in the heating chamber without removing the semiconductor substrate;
• and
• performing an etch to form a trench in the first layer and over the at least one hole, wherein the hardened BARC layer in the at least one hole acts as an etch resistant layer during the etch.