Patterning method using a photomask
View Patent ↗An isolated light-shielding pattern formed from a light-shielding film region 101 and a phase shift region 102 is formed on a transparent substrate 100 serving as a mask. The phase shift region 102 has a phase difference with respect to a light-transmitting region of the transparent substrate 100 . Moreover, the width of the phase shift region 102 is set such that a light-shielding property of the phase shift region 102 becomes at least about the same as that of a light-shielding film having the same width.
1. A patterning method using a photomask, characterized in that it comprises the steps of:
forming a resist film on a substrate;
conducting pattern exposure to the resist film using the photomask; and
developing the resist film subjected to the pattern exposure so as to form a resist pattern,
wherein the photomask includes an isolated light-shielding pattern formed on a transparent substrate that is transparent to an exposure light, and is characterized in that
the light-shielding pattern is formed from a light-shielding film region formed from a light-shielding film, and a phase shift region having an opposite phase with respect to a light-transmitting region of the transparent substrate which has no light-shielding pattern,
the light-shielding pattern includes at least a first light-shielding pattern having a first width and a second light-shielding pattern having a second width larger than the first width,
a first phase shift region, which is part of the phase shift region and is surrounded by the light-shielding film region, is provided in a portion of the first light-shielding pattern, and
only the light-shielding film region is provided in the second light-shielding pattern.
2. The method according to claim 1 , characterized in that
a contour of the light-shielding film region is the same as a feature of the light-shielding pattern.
3. The method according to claim 1 , characterized in that
the light-shielding pattern further includes a third light-shielding pattern having a corner or an end, and
a second phase shift region, which is part of the phase shift region, is provided at or inside the corner of the third light-shielding pattern, or at or inside the end of the third light-shielding pattern.
4. The method according to claim 1 , characterized in that, the first phase shift region has a width Wm, Wm≦(0.4×λ/NA)×M, where λ is a wavelength of the exposure light, NA is a numerical aperture of a reduction projection optical system of an aligner, and M is a magnification of the reduction projection optical system.
5. The method according to claim 1 , characterized in that, the first light-shielding pattern has the first width Lm, Lm≦(0.8×λ/NA)×M.
6. The method according to claim 5 , characterized in that, the first phase shift region has a width Wm, Wm≦((0.8×λ/NA)×M)−Lm and Wm≦Lm.
7. The method according to claim 5 , characterized in that, the first phase shift region has a width Wm, 0.5×((((0.8×λ/NA)×M)−Lm)/2)≦Wm≦1.5×((((0.8×λ/NA)×M)−Lm)/2) and Wm≦Lm.
8. The method according to claim 5 , characterized in that, the second light-shielding pattern has the second width Lm 2 , Lm 2 >(0.8×λ/NA)×M.
9. The method according to claim 1 , characterized in that the phase difference of the phase shift region with respect to the light-transmitting region is (170+360×n) to (190+360×n) degrees, where n is an integer, with respect to a wavelength of the exposure light.
10. The method according to claim 1 , characterized in that the phase difference of the phase shift region with respect to the light-transmitting region is provided by etching the phase-shift region in the transparent substrate.
11. The method according to claim 1 , characterized in that
the phase difference of the phase shift region with respect to the light-transmitting region is provided by forming a phase shifter layer on a portion other than the light-transmitting region in the transparent substrate, and
the phase shifter layer is formed under the light-shielding film region.
12. The method according to claim 1 , characterized in that
the phase difference of the phase shift region with respect to the light-transmitting region is provided by forming a phase shifter layer on a portion other than the light-transmitting region in the transparent substrate, and
the phase shifter layer is formed above the light-shielding film region.
13. The method according to claim 1 , characterized in that the resist film is formed from a positive resist.
14. The method according to claim 1 , characterized in that the phase difference of the phase shift region with respect to the light-transmitting region is provided by etching the light-transmitting region in the transparent substrate.
15. The method according to claim 1 , characterized in that the step of conducting pattern exposure uses an oblique incidence illumination method.
16. A patterning method using a photomask, characterized in that it comprises the steps of:
forming a resist film on a substrate;
conducting pattern exposure to the resist film using the photomask; and
developing the resist film subjected to the pattern exposure so as to form a resist pattern,
wherein the photomask includes an isolated light-shielding pattern formed on a transparent substrate that is transparent to an exposure light, and is characterized in that
the light-shielding pattern is formed from a light-shielding film region formed from a light-shielding film, and a phase shift region having an opposite phase with respect to a light-transmitting region of the transparent substrate which has no light-shielding pattern,
the light-shielding pattern includes a first light-shielding pattern having a width Lm equal to or smaller than 0.18×M, where the unit is μm: M is a magnification of the reduction projection optical system of an aligner,
a first phase shift region, which is part of the phase shift region and is surrounded by the light-shielding film region, is provided in a portion of the first light-shielding pattern.
17. The method according to claim 16 , characterized in that a contour of the light-shielding film region is the same as a feature of the light-shielding pattern.
18. The method according to claim 16 , characterized in that
the light-shielding pattern further includes a second light-shielding pattern having a corner or an end, and
a second phase shift region, which is part of the phase shift region, is provided at or inside the corner of the second light-shielding pattern, or at or inside the end of the second light-shielding pattern.
19. The method according to claim 16 , characterized in that the first phase shift region has a width Wm, Wm≦((0.8×λ/NA)×M)−Lm and Wm≦Lm where λ is a wavelength of the exposure light, NA is a numerical aperture of a reduction projection optical system of an aligner, and M is a magnification of the reduction projection optical system.
20. The method according to claim 16 , characterized in that, provided that the first phase shift region has a width Wm, 0.5×((((0.8×λ/NA)×M)−Lm)/2)≦Wm≦1.5×((((0.8×λ/NA)×M)−Lm)/2) and Wm≦Lm.
21. The method according to claim 16 , characterized in that the phase difference of the phase shift region with respect to the light-transmitting region is (170+360×n) to (190+360×n) degrees, where n is an integer, with respect to a wavelength of the exposure light.
22. The method according to claim 16 , characterized in that the phase difference of the phase shift region with respect to the light-transmitting region is provided by etching the phase-shift region in the transparent substrate.
23. The method according to claim 16 , characterized in that the phase difference of the phase shift region with respect to the light-transmitting region is provided by etching the light-transmitting region in the transparent substrate.
24. The method according to claim 16 , characterized in that
the phase difference of the phase shift region with respect to the light-transmitting region is provided by forming a phase shifter layer on a portion other than the light-transmitting region in the transparent substrate, and
the phase shifter layer is formed under the light-shielding film region.
25. The method according to claim 16 , characterized in that
the phase difference of the phase shift region with respect to the light-transmitting region is provided by forming a phase shifter layer on a portion other than the light-transmitting region in the transparent substrate, and
the phase shifter layer is formed above the light-shielding film region.
26. The method according to claim 16 , characterized in that the resist film is formed from a positive resist.
27. The method according to claim 16 , characterized in that the step of conducting pattern exposure uses an oblique incidence illumination method.