Extreme ultraviolet lithography process and mask

• US 9,442,384 B2
• Filed: 03/12/2014
• Issued: 09/13/2016
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Lu, Yen-Cheng, Yu, Shinn-Sheng, Chen, Jeng-Horng, Yen, Anthony
• Primary Examiner(s): Persaud, Deoram
• Application Number:
  US14/206,516
• Publication Number:
  US 20140268086A1
• Time in Patent Office: 916 Days
• US Class Current: 1/1
• CPC Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like

Abstract

The present disclosure is directed towards lithography processes. In one embodiment, a patterned mask is provided. An information of a position of diffraction light (PDL) on a pupil plane of a projection optics box (POB) is used to define as a light-transmitting region of a pupil filter. The patterned mask is exposed by an on-axis illumination (ONI) with partial coherence σ less than 0.3. The pupil filter is used to transmit diffraction light to a target.

Claims

1. An extreme ultraviolet lithography (EUVL) process, comprising:

providing a patterned mask including a phase-defect region;

receiving information of a position of diffraction light (PDL), diffracted from the patterned mask on a pupil plane of a projection optics box (POB);

exposing the patterned mask by an on-axis illumination (ONI) with partial coherence σ

less than 0.3;

utilizing a pupil filter to control light intensity distribution diffracted from the patterned mask, the pupil filter including;

a light-transmitting region defined by the PDL; and

rest of areas of the pupil filter set to be an opaque region;

compensating, by the pupil filter, for a phase error caused by the phase-defect region at a time of exposure of the patterned mask; and

collecting and directing the diffracted light from the patterned mask to expose a target.

2. The process of claim 1, wherein the light-transmitting region of the pupil filter is further defined by an additional area surrounding the PDL.

3. The process of claim 1, wherein the pupil filter blocks an amount of reflection light, diffracted from the mask, to expose the target.

4. The process of claim 3, wherein the pupil filter is set according to an illumination mode of the ONI.

5. The process of claim 1, wherein the patterned mask includes:

a low thermal expansion material (LTEM) substrate;

a reflective multilayer (ML) above a surface of the LTEM substrate;

a conductive layer above an opposite surface of the LTEM substrate;

a capping layer above the reflective ML;

a buffer layer above the reflective ML layer; and

an absorption layer above the buffer layer.

6. The process of claim 5, wherein the patterned mask includes:

an absorptive region configured as (from top to bottom) the absorption layer layer/the buffer layer/the capping layer/the reflective ML/the LTEM substrate;

a reflective region configured as (from top to bottom) the buffer layer/the capping layer/the reflective ML/the LTEM substrate; and

the phase-defect region inside the reflective region.

7. The process of claim 6, wherein the phase-defect region results from a defect underneath the reflective ML layer.

8. The process of claim 6, wherein the phase-defect region results from a defect embedded in the reflective ML layer.

9. An extreme ultraviolet lithography (EUVL) process, comprising:

receiving a mask for EUVL, the mask includes;

a substrate including a first region and a second region;

a multilayer mirror above the first and second regions;

an absorption layer above the multilayer mirror in the second region; and

a resultant phase-defect region in the first region;

providing information of a position of diffraction light (PDL), diffracted from the mask on a pupil plane of a projection optics box (POB);

exposing the mask by an on-axis illumination (ONI) with partial coherence σ

less than 0.3;

utilizing a pupil filter to control light intensity distribution diffracted from the mask, the pupil filter including;

a light-transmitting region defined by the PDL; and

rest of areas of the pupil filter set to be an opaque region, wherein the pupil filter compensates for the resultant phase-defect region at a time of exposure of the mask; and

collecting and directing the diffracted light from the patterned mask to expose a target.

10. The process of claim 9, wherein the light- transmitting region of the pupil filter is further defined by an additional area surrounding the PDL.

11. The process of claim 9, wherein the pupil filter blocks an amount of reflection light, diffracted from the mask, to expose the target.

12. The process of claim 9, wherein the resultant phase-defect region results from a defect underneath the reflective ML layer.

13. The process of claim 9, wherein the resultant phase-defect region results from a defect embedded in the reflective ML layer.

14. An extreme ultraviolet lithography (EUVL) system, comprising:

a patterned mask having one dimensional patterns, the patterned mask including a phase-defect region;

a dipole illumination with partial coherence σ

less than 0.3 for exposing the mask;

a pupil filter having a light-transmitting region defined by a position of diffracted light (PDL) diffracted from the patterned mask on a pupil plane and an opaque region set to rest area of the pupil filter; and

optics configured to collect diffracted light transmitted through the pupil filter and direct the diffracted light to expose a target, wherein the pupil filter compensates for the phase-defect region during the exposing of the patterned mask.

15. The system of claim 14, wherein the patterned mask includes:

a low thermal expansion material (LTEM) substrate;

a reflective multilayer (ML) above a surface of the LTEM substrate;

a conductive layer above an opposite surface of the LTEM substrate;

a capping layer above the reflective ML;

a buffer layer above the reflective ML layer; and

an absorption layer above the buffer layer.

16. The system of claim 15, wherein the patterned mask includes:

an absorptive region configured as (from top to bottom) the absorption layer layer/the buffer layer/the capping layer/the reflective ML/the LTEM substrate;

a reflective region configured as (from top to bottom) the buffer layer/the capping layer/the reflective ML/the LTEM substrate; and

the phase-defect region inside the reflective region.

17. The system of claim 16, wherein the phase-defect region results from a defect underneath the reflective ML layer.

18. The system of claim 16, wherein the phase-defect region results from a defect embedded in the reflective ML layer.

19. The system of claim 14, wherein the pupil filter blocks an amount of reflection light, diffracted from the mask, to expose the target.

20. The system of claim 14, wherein the light-transmitting region of the pupil filter is further defined by an additional area surrounding the PDL.