Etching method using photoresist etch barrier

• US 20030000920A1
• Filed: 06/10/2002
• Published: 01/02/2003
• Est. Priority Date: 06/28/2001
• Status: Active Grant

• Current Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Original Assignee: Hynix Semiconductor Incorporated (SK Hynix Inc.)
• Inventors: Lee, Sung-Kwon
• Granted Patent: US 7,125,496 B2
• Time in Patent Office: Days
• US Class Current: 216/41
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/312 Organic layers, e.g. photoresist H01L21/3105, H01L21/32 take precedence; photoresists per se G03C
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00
• CPC Class Codes: H01L 21/76897 Formation of self-aligned vias or contact plugs, i.e. involving a lithographically uncritical step self-aligned silicidation on field effect transistors H01L29/665

Abstract

The present invention relates to a method of etching using a photoresist etch barrier formed by an exposure with a light source of which wavelength is in the range of 157 nm to 193 nm, such as an argon fluoride(ArF) laser or fluorine laser(F₂ laser), the method includes the steps of coating a photoresist layer on a etch target layer; forming photoresist pattern by developing the photoresist layer after exposing the photoresist layer with a light source of which wavelength is in the range of 157 nm to 193 nm; forming a polymer layer and etching a portion of the etch target layer simultaneously with a mixture of fluorine-based gas, an Ar gas and an O₂ gas, wherein the fluorine-based gas is C_xF_y or C_aH_bF_b, and wherein x, y, a, b and c range from 1 to 10, respectively; and etching the etch target layer using the polymer layer and the photoresist pattern as the etch mask.

Claims

1. An etching method using a photoresist pattern as an etch mask, comprising the steps of:

coating a photoresist layer on a etch target layer;

forming photoresist pattern by developing the photoresist layer after exposing the photoresist layer with a light source of which wavelength is in the range of 157 nm to 193 nm;

forming a polymer layer and etching a portion of the etch target layer simultaneously with a mixture of fluorine-based gas, an Ar gas and an O₂ gas, wherein the fluorine-based gas is C_xF_y or C_aH_bF_b, and wherein x, y, a, b and c range from 1 to 10, respectively; and

etching the etch target layer using the polymer layer and the photoresist pattern as the etch mask.

2. The method as recited in claim 1, wherein the light source is an ArF laser or F₂ laser.

3. The method as recited in claim 2, wherein the photoresist layer is formed of COMA (cycloolefin-maleic anhydride) family or an acrylate family.

4. The method as recited in claim 1, wherein the polymer layer is formed by supplying approximately 5 sccm to 20 sccm of the fluorine-based gas, approximately 100 sccm to 1000 sccm of an Ar gas, and approximately 1 sccm to 5 sccm of an O₂ gas.

5. The method as recited in claim 4, wherein the polymer layer is formed at a temperature ranging from about 25°

C. to about 80°

C. at a pressure ranging from about 10 mTorr to about 50 mTorr with a power ranging from about 500 W to about 2000 W for approximately 10 seconds to 60 seconds.

6. The method as recited in claim 1, further comprising a step of hardening the photoresist pattern after the step of forming the photoresist pattern.

7. The method as recited in claim 6, wherein Ar ions are injected into the photoresist pattern at the step of hardening the photoresist pattern.

8. The method as recited in claim 7, wherein the Ar ions are implanted by a dose ranging from about 10¹⁰/cm³ to about 10¹⁵/cm³ with an energy ranging from 100 KeV to 300 KeV.

9. The method as recited in claim 6, wherein the photoresist pattern is treated with Ar plasma at the step of hardening the photoresist pattern.

10. The method as recited in claim 9, wherein the step of hardening the photoresist pattern is performed at a pressure ranging from about 1 mTorr to about 10 mTorr with a power ranging from about 500 W to about 2000 W.

11. The method as recited in claim 6, wherein an electron beam is injected into the photoresist pattern at the step of hardening the photoresist pattern.

12. The method as recited in claim 11, wherein an electron beam is injected with energy ranging from about 400 μ

C/cm³ to about 4000 μ

C/cm³.

13. The method as recited in claim 1, further comprising a step of hardening the photoresist pattern after forming the polymer layer.

14. The method as recited in claim 13, wherein Ar ions are injected into the photoresist pattern at the step of hardening the photoresist pattern.

15. The method as recited in claim 14, wherein the Ar ions are implanted by a dose ranging from about 10¹⁰/cm³ to about 10¹⁵/cm³ with an energy ranging from 100 KeV to 300 KeV.

16. The method as recited in claim 13, wherein the photoresist pattern is treated with Ar plasma at the step of hardening the photoresist pattern.

17. The method as recited in claim 16, wherein the step of hardening the photoresist pattern is performed at a pressure ranging from about 1 mTorr to about 10 mTorr with a power ranging from about 500 W to about 2000 W.

18. The method as recited in claim 13, wherein an electron beam is injected with energy ranging from about 400 μ

C/cm³ to about 4000 μ

C/cm³.

19. The method as recited in claim 1, further comprising a step of flowing the photoresist pattern after the step of forming the photoresist pattern.

20. The method as recited in claim 19, wherein the step of flowing the photoresist pattern is performed at a temperature ranging from about 100°

C. to about 220°

C. at normal pressure for 1 minute to 30 minutes using a hot plate, oven or a UV bake.