Use of chromeless phase shift features to pattern large area line/space geometries

• US 20040101765A1
• Filed: 11/27/2002
• Published: 05/27/2004
• Est. Priority Date: 11/27/2002
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Sivakumar, Sam, Nyhus, Paul
• Granted Patent: US 7,056,645 B2
• Time in Patent Office: Days
• US Class Current: 430/5
• CPC Class Codes: G03F 1/34 Phase-edge PSM, e.g. chromeless PSM; Preparation thereof

Abstract

Method for using chromeless phase shift lithography (CPL) masks to pattern large line/space geometries and corresponding CPL masks. The method comprises using a short wavelength light to illuminate a CPL mask comprising a reticle having a plurality of phase-shifting features interspersed with non-phase-arranged in a substantially alternating two-dimensional pattern. When light passes through the phase-shifting features it is phase-shifted relative to light passing through the non-phase-shifting areas of the CPL mask. The phase-shifted and non-phase-shifted light passing through the reticle is then projected onto a resist layer applied over a semiconductor substrate. The resultant composite aerial image intensity distribution is such that an area of the resist having a shape defined by a periphery of a corresponding pattern of phase-shifting features is sufficiently exposed to pattern a large area feature in the resist. Subsequent semiconductor processing operations may then be performed to pattern a corresponding feature in the semiconductor substrate.

Claims

12. A method for patterning a large area feature on a semiconductor substrate, comprising:

providing a chromeless phase shift lithography (CPL) mask comprising a reticle having a plurality of phase-shifting features interspersed with non-phase-shifting areas, said phase-shifting features arranged in a substantially alternating two-dimensional pattern with non-phase shifting areas, said pattern substantially occupying an area on the CPL mask having a shape corresponding to the large area feature;

illuminating the CPL mask with a short wavelength light source, wherein light passing through the phase-shifting features is phase-shifted relative to light passing through the non-phase-shifted areas of the CPL mask; and

projecting phase-shifted and non-phase-shifted light passing through the CPL mask onto a layer of resist applied over the semiconductor substrate to expose an area on the resist corresponding to the large area feature.

13. The method of claim 12, wherein CPL mask is illuminated with an off-axis illumination source.

14. The method of claim 12, wherein the off-axis illumination source comprises a quadruple illumination source.

15. The method of claim 12, wherein the phase-shifting features comprise a plurality of recesses formed in the reticle.

16. The method of claim 12, wherein the phase-shifting features comprise a plurality of mesas extending above non-phase-shifting areas of the reticle.

17. The method of claim 12, further comprising:

developing the resist layer to remove areas of the resist exposed to a sufficient exposure intensity corresponding to the projected aerial image intensity distribution;

depositing a metal layer in areas on the semiconductor from which the resist is removed; and

removing remaining portions of the resist layer.

18. A chromeless phase shift lithography (CPL) mask comprising:

a reticle having a plurality of phase-shifting features formed therein, said plurality of phase-shifting features causing light passing therethough to be shifted approximately 180°

in phase relative to light passing through non-phase-shifting areas of the reticle not occupied by a phase-shifting feature, said phase-shifting features arranged in a substantially alternating two-dimensional pattern with the non-phase-shifting areas of the CPL mask to produce a projected aerial image to pattern one or more large resist areas on a semiconductor substrate.

1. A method for patterning a large area geometry, comprising:

illuminating a chromeless phase shift lithography (CPL) mask comprising a reticle having a plurality of phase-shifting features interspersed with non-phase-shifting areas with a short wavelength light source, wherein light passing through the phase-shifting features is phase-shifted relative to light passing through the non-phase-shifting areas of the CPL mask and wherein the phase-shifting features are arranged in a substantially alternating two-dimensional pattern with non-phase-shifting areas of the CPL mask; and

projecting phase-shifted and non-phase-shifted light passing through the CPL mask onto a layer of resist.

2. The method of claim 1, wherein the plurality of phase-shifting features are arranged in a base pattern comprising a checkerboard pattern.

3. The method of claim 1, wherein the plurality of phase-shifting features are arranged in a base pattern comprising a checkerboard pattern having a substantially filled outside boarder.

4. The method of claim 1, wherein the plurality of phase-shifting features are arranged in a base pattern comprising an island, surrounded by a non-phase shifting area, which in turn is surrounded by a phase-shifting peripheral area.

5. The method of claim 1, wherein the plurality of phase-shifting feature are arranged in a rectangular array.

6. The method of claim 1, wherein CPL mask is illuminated with an off-axis illumination source.

7. The method of claim 1, wherein the off-axis illumination source comprises a quadruple illumination source.

8. The method of claim 1, wherein the phase-shifting features comprise a plurality of recesses formed in the reticle.

9. The method of claim 1, wherein the phase-shifting features comprise a plurality of mesas extending above non-phase-shifting areas of the reticle.

10. The method of claim 1, wherein the large area geometry has a shape defined by a polygon having at least five sides.

11. The method of claim 1, wherein the short wavelength light source produces light having a wavelength of one of 248, 193, or 157 nanometers.

19. The method of claim 1, wherein the plurality of phase-shifting features are arranged in a base pattern comprising a checkerboard pattern.

20. The method of claim 1, wherein the plurality of phase-shifting features are arranged in a base pattern comprising a checkerboard pattern having a substantially filled outside boarder.

21. The method of claim 1, wherein the plurality of phase-shifting features are arranged in a base pattern comprising an island, surrounded by a non-phase shifting area, which in turn is surrounded by a phase-shifting peripheral area.

22. The CPL mask of claim 18, wherein the plurality of phase-shifting feature are arranged in a rectangular array.

23. The CPL mask of claim 18, wherein at least one of said one or more large resist areas is non-rectangular.

24. The CPL mask of claim 18, wherein the plurality of phase-shifting features comprise a plurality of recesses formed in the quartz substrate.

25. The CPL mask of claim 18, wherein the plurality of phase-shifting features comprise a plurality of mesas extending upward from the quartz substrate.

26. The CPL mask of claim 18, wherein the phase-shifting features are substantially square in shape.

27. The CPL mask of claim 18, wherein the plurality of phase-shifting features are arranged in a pattern occupying a peripheral area having a shape defined by a polygon having at least five sides.

25-1. The CPL mask of claim 18, wherein reticle comprises quartz.