Method of forming resist pattern, and exposure device

• US 6,511,794 B1
• Filed: 09/18/2000
• Issued: 01/28/2003
• Est. Priority Date: 03/27/2000
• Status: Expired due to Fees

• Current Assignee: LAPIS Semiconductor Co., Ltd. (ROHM Co., Ltd.)
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Furukawa, Takamitsu
• Primary Examiner(s): Duda, Kathleen
• Application Number:
  US09/664,003
• Time in Patent Office: 862 Days
• Field of Search: 430/311, 430/322, 430/328, 430/330, 430/394
• US Class Current: 430/328
• CPC Class Codes: G03F 7/2024 of the already developed image
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking

Abstract

A method of forming a resist pattern and an exposure device using the method are provided in which a relatively large pattern, whose dimension is greater than a resolution limit of a KrF exposure technique, and an extremely fine pattern, whose dimension is less than or equal to the resolution limit of the KrF exposure technique, can be formed well and simultaneously. Two patterns are exposed simultaneously by deep UV light of a wavelength of 248 nm on a resist film 10 formed of TDUR-P015 and formed on a surface of an SiO₂ film 12. The two patterns are: a circular pattern of a dimension which is made larger, in accordance with a shrinkage rate, than a finally required pattern dimension, which circular pattern is formed at regions to be shrunk; and a circular pattern of a dimension which is finally required, which circular pattern is formed at regions not to be shrunk. A UV light exposure amount, which is of an amount such that heat resistance of the TDUR-P015 forming the resist film 10 improves and the resist pattern does not shrink, is applied only onto the regions not to be shrunk of the resist pattern obtained by development. Then, high temperature bake processing at 135° C. for 60 seconds is carried out.

Claims

1. A method of forming a resist pattern, comprising the steps of:

(a) applying a resist to an object surface;

(b) subjecting the resist to pattern exposure by irradiating the resist with light directed through a first reticle;

(c) developing the resist, wherein the developed resist pattern has first regions not to be shrunk in which a plurality of patterns having intervals that are smaller than a predetermined distance are provided, and second regions to be shrunk at a predetermined shrinkage rate in which a plurality of patterns having intervals that are larger than a predetermined distance are provided;

(d) providing the first regions not to be shrunk with resistance to shrinkage during a bake process by irradiating the resist with light directed through a second reticle, the light only reaching said first regions;

(e) adjusting a shrinkage rate of the resist pattern by irradiating the entire resist with light; and

(f) baking the resist.

2. The method of claim 1, wherein the step of adjusting a shrinkage rate includes irradiating areas of the resist with light of at least 2.7 mJ/cm².

3. The method of claim 1, wherein the step of adjusting a shrinkage rate includes irradiating areas of the resist with light of at least 3.3 mJ/cm².

4. The method of claim 1, wherein the step of adjusting a shrinkage rate includes providing the second reticle for passing light therethrough for exposing areas of the resist which are not to be shrunk.

5. The method of claim 1, further comprising the step of irradiating the resist with light in an amount from 2.7 to 3.3 mJ/cm².

6. The method of claim 5, wherein the step of irradiating the resist with light in the amount from 2.7 to 3.3 mJ/cm² includes irradiating areas of the resist in accordance with temperature differentials that arise in the resist during the step of baking.

7. A method of forming a resist pattern comprising the steps of:

subjecting a resist, which is applied on a surface of an object to be processed, to pattern exposure in which a first exposure amount for forming a pattern is applied to the resist;

forming a resist pattern by developing the resist, wherein the resist pattern has first regions not to be shrunk in which a plurality of patterns having intervals that are smaller than a predetermined distance are provided, and second regions to be shrunk at a predetermined shrinkage rate in which a plurality of patterns having intervals that are larger than a predetermined distance are provided;

applying a second exposure amount to the first regions not to be shrunk, providing the first regions of the resist pattern not to be shrunk with resistance to shrinkage during a bake process;

applying a third exposure amount, which adjusts a shrinkage rate of the resist pattern, to the resist pattern thereby exposing the second regions to be shrunk to the third exposure amount corresponding to the predetermined shrinkage rate; and

subjecting the resist to a bake process at a temperature at which the resist flows, thereby shrinking the second regions to be shrunk.

8. The method of forming a resist pattern of claim 7, wherein the second exposure amount is an exposure amount at least equal to a saturation exposure amount of the resist.

9. The method of forming a resist pattern of claim 7, further comprising the step of:

adjusting the third exposure amount for each of predetermined regions of the object to be processed in accordance with shrinkage rate differentials due to a distribution of temperatures arising during the step of subjecting the resist to a bake process.

10. The method of forming a resist pattern of claim 9, wherein the step of adjusting the third exposure amount is carried out at the time of third exposure by adding a correction amount to a pre-correction second exposure amount.

11. The method of forming a resist pattern of claim 9, wherein the step of adjusting the third exposure amount is carried out by performing an additional exposure at an exposure amount corresponding to a correction amount, after the third exposure has been carried out at a pre-correction third exposure amount.

12. The method of forming a resist pattern of claim 7, further comprising the step of:

correcting the third exposure amount for each of predetermined regions of the object to be processed for eliminating a distribution of errors in shrinkage rates of a pattern to finally be formed on the object.

13. The method of forming a resist pattern of claim 12, wherein the step of adjusting the third exposure amount is carried out at the time of third exposure by adding a correction amount to a pre-correction third exposure amount.

14. The method of forming a resist pattern of claim 12, wherein the step of adjusting the third exposure amount is carried out by performing an additional exposure at an exposure amount corresponding to a correction amount, after the third exposure has been carried out at a pre-correction third exposure amount.

15. The method of forming a resist pattern of claim 7, wherein the resist is a resist for use with UV light, and exposures are performed using UV light.

16. The method of forming a resist pattern of claim 7, further comprising the step of:

adjusting the shrinkage rate of the resist pattern by adjusting bake temperature while subjecting the resist to the bake process.

17. A method of forming a resist pattern comprising the steps of:

subjecting a resist, which is applied on a surface of an object to be processed, to pattern exposure in which a first exposure amount for forming a pattern is applied to the resist;

forming a resist pattern by developing the resist, wherein the resist pattern has first regions not to be shrunk in which a plurality of patterns having contact holes whose diameters are smaller than a predetermined distance are provided, and second regions to be shrunk at a predetermined shrinkage rate in which a plurality of patterns having contact holes whose diameters are larger than a predetermined distance are provided;

applying a second exposure amount to the first regions not to be shrunk, providing the first regions of the resist pattern not to be shrunk with resistance to shrinkage during a bake process;

applying a third exposure amount, which adjusts a shrinkage rate of the resist pattern, to the resist pattern thereby exposing the second regions to be shrunk to the third exposure amount corresponding to the predetermined shrinkage rate; and

subjecting the resist to a bake process at a temperature at which the resist flows, thereby shrinking the second regions to be shrunk.

18. The method of claim 17, wherein said predetermined distance is 0.5 μ

m.

19. A method of forming a resist pattern, comprising the steps of:

(a) applying a resist to an object surface;

(b) subjecting the resist to pattern exposure by irradiating the resist with light directed through a first reticle;

(c) developing the resist, wherein the developed resist pattern has first regions not to be shrunk in which a plurality of patterns having contact holes whose diameters are smaller than a predetermined distance are provided, and second regions to be shrunk at a predetermined shrinkage rate in which a plurality of patterns having contact holes whose diameters are larger than a predetermined distance are provided;

(d) providing the first regions not to be shrunk with resistance to shrinkage during a bake process by irradiating the resist with light directed through a second reticle, the light only reaching said first regions;

(e) adjusting a shrinkage rate of the resist pattern by irradiating the entire resist with light; and

(f) baking the resist.

20. The method of claim 19, wherein said predetermined distance is 0.5 μ

m.