Process for forming low dielectric constant insulation layer on integrated circuit structure

A process for forming a low dielectric constant insulation layer on an integrated circuit structure on a semiconductor wafer which comprises:

• a) depositing a composite layer over an integrated circuit structure on a semiconductor wafer comprising one or more matrix-forming insulation materials and one or more extractable materials;
• and
• b) removing said one or more extractable materials by:
• i) contacting said composite layer with a first liquid which is a solvent for said one or more extractable materials but not for said one or more matrix-forming materials to form a solution of said first liquid and said one or more extractable materials;
• ii) removing the resulting solution of said first liquid and said one or more extractable materials from said composite layer by rinsing said composite layer in a second liquid which is miscible with said first liquid and which also is not a solvent for said one or more matrix-forming materials;
• iii) removing said second liquid from said composite layer by lowering the temperature of said semiconductor wafer to a temperature below the freezing point of said second liquid in a vacuum chamber;
• and
• iv) maintaining said semiconductor wafer at said temperature in said vacuum chamber until substantially all of said second liquid has been removed from said composite layer;
• thereby leaving a porous structure comprising said low dielectric constant insulation layer.

A process for forming a low dielectric constant insulation layer on an integrated circuit structure on a semiconductor wafer which comprises:

• a) depositing a composite layer over an integrated circuit structure on a semiconductor wafer comprising one or more matrix-forming insulation materials and one or more extractable materials;
• and
• b) removing said one or more extractable materials by:
• i) contacting said composite layer with a first liquid which is a solvent for said one or more extractable materials but not for said one or more matrix-forming materials;
• ii) removing the resulting solution of said first liquid and said one or more extractable materials from said composite layer by rinsing said composite layer in a second liquid which is miscible with said first liquid and which also is not a solvent for said one or more matrix-forming materials;
• iii) removing said second liquid from said composite layer in a pressurized chamber by first raising the pressure in said chamber above the critical point of said second liquid and then raising the temperature of said composite layer to a temperature above the critical point of said second liquid;
• iv) maintaining said wafer at said temperature and pressure until substantially all of said second liquid has been removed from said composite layer;
• thereby leaving a porous structure comprising said low dielectric constant insulation layer.

A process for forming a low dielectric constant insulation layer on an integrated circuit structure on a semiconductor wafer which comprises:

• a) forming a composite gel layer over an integrated circuit structure on a semiconductor wafer, said composite gel layer comprising one or more matrix-forming insulation materials and one or more extractable materials;
• and
• b) removing said one or more extractable materials by:
• i) contacting said composite gel layer with a first liquid which is a solvent for said one or more extractable materials but not for said one or more matrix-forming materials to form a solution of said first liquid and said one or more extractable materials;
• ii) removing the resulting solution of said first liquid and said one or more extractable materials from said composite gel layer by rinsing said composite gel layer in a second liquid which is miscible with said first liquid and which also is not a solvent for said one or more matrix-forming materials;
• iii) removing said second liquid from said composite gel layer by lowering the temperature of said semiconductor wafer to a temperature below the freezing point of said second liquid in a vacuum chamber;
• and
• iv) maintaining said semiconductor wafer at said temperature in said vacuum chamber until substantially all of said second liquid has been removed from said composite layer;
• thereby leaving a porous structure comprising said low dielectric constant insulation layer.

A process for forming a low dielectric constant insulation layer on an integrated circuit structure on a semiconductor wafer which comprises:

• a) forming a composite layer over an integrated circuit structure on a semiconductor wafer comprising one or more matrix-forming insulation materials and one or more extractable materials;
• and
• b) removing said one or more extractable materials by:
• i) contacting said composite layer with a first liquid which is a solvent for said one or more extractable materials but not for said one or more matrix-forming materials and selected from the group consisting of an alcohol and 2-methyl tetrahydrofuran;
• ii) removing the resulting solution of said first liquid and said one or more extractable materials from said composite layer by rinsing said composite layer in a second liquid which is miscible with said first liquid and which also is not a solvent for said one or more matrix-forming materials;
• iii) removing said second liquid from said composite layer in a pressurized chamber by first raising the pressure in said chamber above the critical point of said second liquid and then raising the temperature of said composite layer to a temperature above the critical point of said second liquid;
• iv) maintaining said wafer at said temperature and pressure until substantially all of said second liquid has been removed from said composite layer;
• thereby leaving a porous structure comprising said low dielectric constant insulation layer.

A process for forming a low dielectric constant insulation layer on an integrated circuit structure on a semiconductor wafer which comprises:

• a) forming a composite gel layer over an integrated circuit structure on a semiconductor wafer, said composite gel layer comprising one or more matrix-forming insulation materials and one or more extractable materials;
• and
• b) removing said one or more extractable materials by:
• i) contacting said composite gel layer with a first liquid which is a solvent for said one or more extractable materials but not for said one or more matrix-forming materials;
• ii) removing the resulting solution of said first liquid and said one or more extractable materials from said composite layer by rinsing said composite gel layer in a second liquid which is miscible with said first liquid and which also is not a solvent for said one or more matrix-forming materials;
• iii) removing said second liquid from said composite gel layer in a pressurized chamber by first raising the pressure in said chamber above the critical point of said second liquid and then raising the temperature of said composite layer to a temperature above the critical point of said second liquid;
• iv) maintaining said wafer at said temperature and pressure until substantially all of said second liquid has been removed from said composite layer;
• thereby leaving a porous structure comprising said low dielectric constant insulation layer.