Source: https://patents.justia.com/patent/20070082278
Timestamp: 2020-05-29 21:06:31
Document Index: 628654182

Matched Legal Cases: ['artz 6', 'artz 8', 'artz 9', 'artz 10', 'artz 4', 'artz 5']

US Patent Application for Halftone phase shift mask blank, halftone phase shift mask, and method of producing the same Patent Application (Application #20070082278 issued April 12, 2007) - Justia Patents Search
Justia Patents US Patent Application for Halftone phase shift mask blank, halftone phase shift mask, and method of producing the same Patent Application (Application #20070082278)
Halftone phase shift mask blank, halftone phase shift mask, and method of producing the same
Jul 3, 2006 -
This is a divisional of application Ser. No.10/370,776 filed Feb. 24, 2003. The entire disclosure(s) of the prior application(s), application number(s) 10/370,776 is hereby incorporated by reference.
The double-layer halftone phase shift mask is described, for example, in Japanese Unexamined Patent Publication No. H4-136854 in which the halftone phase shifter portion has a double-layer structure comprising a thin Cr layer and a coating glass (Prior-art Example 1).
The upper layer is made of a material substantially consisting of silicon, oxygen, and nitrogen. That is, the upper layer comprises a film containing silicon, oxygen, and nitrogen as main components. This material is advantageous in the following respects. Specifically, even if the exposure light beam has a shortened wavelength, a desired transmittance and a phase difference can be controllably achieved in combination with the lower layer. In addition, the irradiation resistance against the exposure light beam and the chemical resistance against the cleaning liquid or the like are high.
Furthermore, since a relatively high refractive index can be obtained, it is possible to suppress the total film thickness of the halftone phase shifter film sufficient to obtain a desired phase difference. Therefore, the fine processability of the halftone phase shifter film is superior.
On the other hand, the latter etching stopper film having a function ofr facilitating detection of an etching end point of the phase shifter film is a film made of a material in which the difference in reflectance for an etching end point detection light beam (e.g., 680 nm) between the transparent substrate (e.g., the synthetic quartz substrate) and the etching stopper is greater than that between the transparent substrate and the SiOxNy film.
Thus, the present inventors have found out that the etching characteristic with respect to the chlorine-based gas is maintained and the resistance against the fluorine-based gas is remarkably improved by adding a small amount of the metal selected from the first group to the metal selected from the second group. The added amount of the metal selected from the first group with respect to the metal selected from the second group is selected to be 2% or more. If the added amount is smaller than 2%, the characteristic of the added material is not fully exhibited and the effect of improving the resistance against the fluorine-based gas is insufficient.
In case where the upper layer of the phase shifter film is made of a Si-based material such as SiOx, SiNx, SiOxNy, SiCx, SiCxNy, or SiCxOyNz, or a material containing the Si-based material and a metal M (for example, at least one of Mo, Ta, W, Cr, Zr, Hf) added thereto so that M/(Si+H)×100 is preferably 10 atomic % or less, the upper layer can easily be processed by the dry etching using the fluorine-based gas and has a high resistance against the dry etching using the chlorine-based gas. In case where the upper layer is made of the above-mentioned material, it is possible to satisfy the predetermined transmittance and the predetermined phase shift amount, even if the exposure wavelength is shortened to 193nm as the wavelength of the ArF excimer laser or 157nm as the wavelength of the F2 excimer laser. Thus, it is possible to adapt to the shortened wavelength.
Specifically, assuming that the phase shift amount of the exposure light beam passing through the upper layer (phase adjustment layer) and having a wavelength λ is represented by φ (deg), the film thickness d of the phase adjustment layer is given by:
where n represents the refractive index of the phase adjustment layer with respect to the light beam having the wavelength k.
FIGS. 1A and 1B show sectional views of a halftone phase shift mask blank and a halftone phase shift mask according to an embodiment of the present invention, respectively;
FIGS. 2A through 2D are views for describing a sequence of steps of processing each layer in Example 2;
FIGS. 3A through 3E are views for describing a sequence of steps of processing each layer in Example 3;
FIGS. 4A through 4E are views for describing a sequence of steps of processing each layer in Comparative Example 2;
FIGS. 5A through 5D are views for describing a first half of a manufacturing process of a halftone phase shift mask blank and a halftone phase shift mask in each of Examples 5 through 10 and Comparative Examples 3 through 5;
FIGS. 6A through 6D are views for describing a second half of the manufacturing process following the first half in FIGS. 5A through 5D;
FIG. 7 is a spectrum diagram of an optical characteristic of the halftone phase shift mask blank in Example 5;
FIG. 8 is a spectrum diagram of the optical property of the halftone phase shift mask blank in Example 6; and
FIG. 9 is a view showing a modification of the halftone phase shift mask blank and the halftone phase shift mask according to the embodiment of the present invention.
TABLE 1 Zr content Etching rate Selection ratio (%) Etching gas (Å/min) (/QZ)
TaZrx Cl2 4020 11.2 Zr 100 Cl2 3370 9.4 QZ 0 Cl2 360 — TaZrx 1.8 C2F6 40 0.3 TaZrx 2.6 C2F6 40 0.3 TaZrx 4.3 C2F6 10 0.1 Zr 100 C2F6 7 0.1 QZ 0 C2F6 120 —
TABLE 2 Etching rate Selection ratio Etching gas (Å/min) (/QZ)
TaAl Cl2 2880 11.5 TaHf Cl2 2980 11.0 QZ Cl2 260 — TaAl C2F6 70 0.6 TaHf C2F6 20 0.2 QZ C2F6 110 —
TABLE 3 Etching rate Selection ratio Etching gas (Å/min) (/QZ)
Ta Cl2 2900 8.1 QZ Cl2 360 — Ta C2F6 110 0.9 QZ C2F6 120 —
FIGS. 7 and 8 show transmittance and reflectance curves with respect to the wavelengths in Examples 5 and 6, respectively. In Examples 5 and 6, for the transmittances with respect to the exposure light beam (F2 excimer laser) a standard product (6%) and a high-transmittance product (around 9%) were realized. The reflectance for the exposure light beam was low and satisfied a required range (20% or less). The transmittance for the inspection light beam was also lower than an upper limit of the required value (40% or less). Thus, these examples were sufficiently adapted for the inspection.
TABLE 4 Inspec- Inspec- Exposure Exposure tion tion wave- wave- Inspec- wave- wave- Upper layer Lower layer Exposure length length tion length length Upper film thick- film thick- wave- trans- reflec- wave- trans- reflec- Transparent layer ness Lower layer ness length mittance tance length mittance tance substrate material (Å) material (Å) (nm) (%) (%) (nm) (%) (%)
Example 5 F doped SiON{circle around (1)} 790 Ta—Hf{circle around (1)} 100 157 6.20 15.60 257 19.91 32.79 synthetic quartz 6 CaF2 SiON{circle around (1)} 800 Ta—Hf{circle around (1)} 65 157 9.14 13.55 257 32.39 24.78 7 F doped SiON{circle around (1)} 810 Ta—Hf{circle around (2)} 35 157 14.0 12.00 257 49.30 16.80 synthetic quartz 8 Synthetic SiON{circle around (2)} 740 Ta—Hf{circle around (1)} 75 193 15.1 17.00 364 30.40 21.50 quartz 9 Synthetic SiON{circle around (4)} 960 Hf—Si 100 193 15.83 18.58 364 19.6 38.89 quartz 10 CaF2 SiON{circle around (3)} 920 Hf—Si 40 157 11.35 9.28 257 46.58 17.83 Compara- 3 F doped SiON{circle around (4)} 770 Ta 60 157 7.33 14.37 257 35.4 24.06 tive- synthetic Example quartz 4 F doped SiON{circle around (3)} 807 TaCr 80 157 6.30 18.20 257 29.40 25.13 synthetic quartz 5 F doped SiON{circle around (4)} 790 Si 40 157 9.76 11.95 257 43.4 16.93 synthetic quartz
TABLE 5 Composition 157 nm 193 nm (atomic %)
SiON n k n k Si O N 2.00 0.20 — — 36 48 16 SiON — — 2.22 0.18 40 27 33 SiON 2.05 0.22 — — 36 46 18 SiON 2.17 0.30 2.05 0.10 38 38 24
TABLE 6 Ta Hf Si Cr Zr
Ta—Hf 90 10 Ta—Hf 80 20 Hf—Si 17 83 Ta—Cr 96 4
TABLE 7 Etching selection ratio Etching selection of lower layer to upper ratio of lower layer to layer substrate (SF6 + He) (Cl2)
Example 5 0.25 >5 6 0.25 >5 7 0.08 >5 8 0.25 >5 9 0.17 >5 10 0.17 >5 Comparative 3 0.67 >5 Example 4 0.25 2.50 5 8.08 —
2. A halftone phase shift mask blank for use in manufacturing a halftone phase shift mask comprising a transparent substrate, a light transmitting portion formed on the substrate for transmitting an exposure light beam, a phase shifter portion formed on the substrate for transmitting a part of the exposure light beam as a transmitted light beam and for shifting a phase of the transmitted light beam by a predetermined amount, the halftone phase shift mask being designed so that light beams passing through the light transmitting portion and through the phase shifter portion cancel each other in the vicinity of a boundary portion therebetween, thereby keeping a predetermined contrast at a boundary portion of an exposure pattern to be transferred onto the surface of an object to be exposed, wherein:
3. The halftone phase shift mask blank according to claim 1 or 2, wherein:
4. The halftone phase shift mask blank according to claim 1 or 2, wherein:
5. A halftone phase shift mask comprising a transparent substrate having a mask pattern formed thereon and including a light transmitting portion and a light semi-transmitting portion, the mask pattern being formed by etching the halftone phase shifter film in the halftone phase shift mask blank according to claim 1 or 2.
6. A method of manufacturing the halftone phase shift mask according to claim 5, comprising the steps of:
etching the upper layer by dry etching using a fluorine-based gas; and
Publication number: 20070082278
Patent Grant number: 7632612
Inventors: Yuuki Shiota (Akishima-shi), Osamu Nozawa (Fuchu-shi), Ryo Ohkubo (Akishima-shi), Hideaki Mitsui (Fuchu-shi)
Application Number: 11/478,687
Current U.S. Class: 430/5.000; 428/428.000; 428/430.000; 378/35.000; 430/322.000; 430/323.000
International Classification: B32B 9/00 (20060101); B32B 17/06 (20060101); G03C 5/00 (20060101); G21K 5/00 (20060101); B32B 17/10 (20060101); G03F 1/00 (20060101);