Method for Shrinking Opening Sizes of a Photoresist Pattern

Abstract

A method for shrinking opening sizes of a photoresist is provided. A patterned photoresist layer having an opening is formed on a substrate. The opening includes a first size. The photoresist layer is baked at a temperature below a glass transition temperature of the photoresist layer. A layer of SAFIER material is formed on the photoresist layer and the substrate. The layer of SAFIER material and the photoresist layer are baked at a temperature higher than the glass transition temperature to shrink the size of the opening. The layer of SAFIER material is removed. The first size of the opening is thus shrunk to a second size.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the following detailed description of the preferred embodiment, with reference made to the accompanying drawings as follows:

FIGS. 1A and 1B are cross-section schematic diagrams illustrating a traditional structure after performing a thermal flow process.

FIG. 2A to 2F are cross-sectional diagrams illustrating a contact hole formed on a substrate according to one embodiment of the present invention.

FIG. 3 is a process flow diagram illustrating a SAFIER shrinking process according to one embodiment of the present invention.

Claims

1. A method of shrinking opening sizes of a photoresist pattern, the method comprising: forming a patterned photoresist layer having at least an opening on a substrate;baking the patterned photoresist layer at a first temperature below a glass transition temperature of the patterned photoresist layer;coating an enhanced shrinking layer on the patterned photoresist layer and the substrate to fill the opening;baking the enhanced shrinking layer and the patterned photoresist layer at a second temperature higher than the glass transition temperature; andremoving the enhanced shrinking layer.

2. The method of shrinking opening sizes of a photoresist pattern of claim 1, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises performing baking gradation processes at a lower temperature below the glass transition temperature.

3. The method of shrinking opening sizes of a photoresist pattern of claim 1, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises performing a plurality of baking/cooling gradation processes to bake the patterned photoresist layer.

4. The method of shrinking opening sizes of a photoresist pattern of claim 3, wherein the temperature for each of the baking processes is higher than the temperature of its preceding baking process.

5. The method of shrinking opening sizes of a photoresist pattern of claim 3, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises a first baking gradation and a second baking gradation, wherein temperature of the first baking gradation is below the glass transition temperature and temperature of the second baking gradation is close to but below the glass transition temperature.

6. The method of shrinking opening sizes of a photoresist pattern of claim 1, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises performing a baking process at a single temperature close to but below the glass transition temperature.

7. The method of shrinking opening sizes of a photoresist pattern of claim 1, wherein the opening is shrunk more than 50 nm in width.

8. The method of shrinking opening sizes of a photoresist pattern of claim 1, wherein the step of removing the enhanced shrinking layer comprises using deionized water.

9. A method of forming a hole, the method comprising: forming a dielectric layer on a substate;forming a patterned photoresist layer having at least an opening on the dielectric layer;baking the patterned photoresist layer at a first temperature below a glass transition temperature of the patterned photoresist layer;coating an enhanced shrinking layer on the patterned photoresist layer and the substrate to fill the opening;baking the enhanced shrinking layer and the patterned photoresist layer at a second temperature over the glass transition temperature to shrink the opening in width;removing the enhanced shrinking layer; andetching the exposed dielectric layer to form at least a hole.

10. The method of shrinking opening sizes of a photoresist pattern of claim 9, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises performing baking gradation processes at a low temperature to below the glass transition temperature.

11. The method of shrinking opening sizes of a photoresist pattern of claim 9, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises performing a plurality of baking/cooling gradation processes to bake the patterned photoresist layer.

12. The method of shrinking opening sizes of a photoresist pattern of claim 11, wherein the temperature for each of baking processes is higher than the temperature of its baking process.

13. The method of shrinking opening sizes of a photoresist pattern of claim 11, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises a first baking gradation and a second baking gradation, wherein temperature of the first baking gradation is below the glass transition temperature and temperature of the second baking gradation is close to but below the glass transition temperature.

14. The method of shrinking opening sizes of a photoresist pattern of claim 9, wherein the step of baking the patterned photoresist layer at the first temperature below the glass transition temperature further comprises performing a baking process at a single temperature close to but below the glass transition temperature.

15. The method of shrinking opening sizes of a photoresist pattern of claim 9, wherein the opening is shrunk more than 50 nm in width.

16. The method of shrinking opening sizes of a photoresist pattern of claim 9, wherein the step of removing the enhanced shrinking layer comprises using deionized water.