Materials and Methods for Forming Resist Bottom Layer

A method, comprising:

• spin-coating a semiconductor substrate with a material layer, wherein the material layer includes a polymer attached to at least one ultraviolet (UV) cross-linker and at least one thermal cross-linker, and wherein an amount of the at least one UV cross-linker in the material layer is greater than an amount of the at least one thermal cross-linker in the material layer;
• exposing the material layer to a first UV source having a first wavelength, resulting in an exposed material layer, wherein the exposing induces cross-linking of the at least one UV cross-linker;
• thermally curing the exposed material layer, resulting in a cured material layer, wherein the curing induces cross-linking of the at least one thermal cross-linker;
• and
• forming a photoresist layer over the cured material layer.

A method, comprising:

• forming a bottom layer over a semiconductor substrate, the bottom layer including a polymer, a first cross-linker configured to cross-link under ultraviolet (UV) exposure, and a second cross-linker configured to cross-link under heat exposure at a first temperature, wherein the first and the second cross-linkers are bonded to the polymer;
• performing a first heat exposure to the bottom layer at a second temperature lower than the first temperature;
• after the performing of the first heat exposure, performing a UV exposure to the bottom layer to induce cross-linking of the first cross-linker, resulting in an exposed bottom layer;
• performing a second heat exposure to the exposed bottom layer at a third temperature to result in a cured bottom layer, wherein the third temperature is higher than the first temperature;
• forming a middle layer over the cured bottom layer;
• and
• forming a photoresist layer over the middle layer.