US4368230A
Expired / Lapsed
US
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Photomask
Assignee: Hitachi Ltd
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Filing: 1980-03-05
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Granted: 1983-01-11
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Expires: 2000-03-05
Abstract
Abstract A photomask comprises a transparent film of conductive material and a light shielding film of predetermined pattern on a transparent substrate. The pattern film is made of a metallic element having its atomic number not smaller than 25 or a composition containing the metallic element. The photomask structure is suited to the case where the pattern formed on the mask is inspected with an electron beam. With the mask structure, the contrast of a pattern related information signal (backscattered electrons, secondary electrons, absorption current, etc.) derived from the mask upon irradiation thereof with the electron beam is improved.
Inventors
- 👤 Koichiro Mizukami
- 👤 Masatoshi Migitaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:35
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/82; G03F1/84; G03F1/86; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24851; Y10T428/24868; Y10T428/24917; Y10T428/24926; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
126 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising: a transparent substrate comprised of glass; a transparent electrically conductive film comprised of metal oxide formed of at least one first metallic element; and a light shielding film of predetermined pattern provided on said transparent electrically conductive film, said pattern film being comprised of at least one material selected from the group consisting of a second metallic element having an atomic number not smaller than 25 and a composition containing said second metallic element, said first and second metallic elements being different from each other and the ratio of the electron backscattering coefficient of said pattern film to that of said transparent electrically conductive film being equal to or larger than about 1.3
Claim 2
Dependent Claim
126 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising: a transparent substrate comprised of glass; a transparent electrically conductive film comprised of metal oxide formed of at least one first metallic element; and a light shielding film of predetermined pattern provided on said transparent electrically conductive film, said pattern film being comprised of at least one material selected from the group consisting of a second metallic element having an atomic number not smaller than 25 and a composition containing said second metallic element, said first and second metallic elements being different from each other and the ratio of the electron backscattering coefficient of said pattern film to that of said transparent electrically conductive film being equal to or larger than about 1.3
Claim 3
Dependent Claim
141 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising: a transparent substrate comprised of glass; a light shielding film of predetermined pattern provided on said substrate, said pattern film being comprised of at least one material selected from the group consisting of a metallic element having an atomic number not smaller than 25 and a composition containing said metallic element; and a transparent electrically conductive film being comprised of metal oxide formed of at least one metallic element and provided on a surface of said substrate including said pattern film, the metallic elements forming said light shielding film and the transparent electrically conductive film being different from each other and the ratio of the electron backscattering coefficient of said pattern film to that of said transparent electrically conductive film being equal to or larger than about 1.3.
Claim 4
Dependent Claim
141 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising: a transparent substrate comprised of glass; a light shielding film of predetermined pattern provided on said substrate, said pattern film being comprised of at least one material selected from the group consisting of a metallic element having an atomic number not smaller than 25 and a composition containing said metallic element; and a transparent electrically conductive film being comprised of metal oxide formed of at least one metallic element and provided on a surface of said substrate including said pattern film, the metallic elements forming said light shielding film and the transparent electrically conductive film being different from each other and the ratio of the electron backscattering coefficient of said pattern film to that of said transparent electrically conductive film being equal to or larger than about 1.3.
Claim 5
Dependent Claim
37 words
A photomask according to claim 1 or 2, wherein the thickness of said pattern film is equal to or larger than about 0.2 times of the mean range of electron in the material forming said pattern film.
Claim 6
Dependent Claim
31 words
A photomask according to claim 1 or 2, wherein said metallic element of said pattern film is one selected from a group consisting of gold, platinum, tungsten, tantalum, lead and molybdenum.
Claim 7
Dependent Claim
23 words
A photomask according to claim 1 or 2, wherein the thickness of said transparent conductive film is not larger than about 2,000 A.
Claim 8
Dependent Claim
23 words
A photomask according to claim 1 or 2, further comprising an adhesive film provided between said transparent conductive film and said pattern film.
Claim 9
Dependent Claim
114 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising, on a transparent glass substrate, an electrically conductive transparent film and a light shielding film of predetermined pattern, said light shielding film being formed of at least one metal selected from the group consisting of gold, platinum, tungsten, tantalum, lead and molybdenum and said electrically conductive transparent film being formed of metal oxide of at least one metal selected from the group consisting of indium, tin, titanium and zinc, the thickness of said light shielding film of a predetermined pattern being equal to or larger than about 0.2 times the mean range of electron in the material forming said pattern film.
Claim 10
Dependent Claim
114 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising, on a transparent glass substrate, an electrically conductive transparent film and a light shielding film of predetermined pattern, said light shielding film being formed of at least one metal selected from the group consisting of gold, platinum, tungsten, tantalum, lead and molybdenum and said electrically conductive transparent film being formed of metal oxide of at least one metal selected from the group consisting of indium, tin, titanium and zinc, the thickness of said light shielding film of a predetermined pattern being equal to or larger than about 0.2 times the mean range of electron in the material forming said pattern film.
Claim 11
Dependent Claim
22 words
A photomask according to claim 7, wherein the thickness of said electrically conductive transparent film is not larger than about 2000 A.
Claim 12
Dependent Claim
104 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising: a transparent glass substrate; a transparent electrically conductive film formed on said transparent glass substrate, said transparent electrically conductive film being formed of metal oxide of at least one metallic element having an atomic number equal to or smaller than 50; and a light shielding film of predetermined pattern provided on said transparent electrically conductive film, said pattern film being formed of at least one material selected from the group consisting of another metallic element having an atomic number not smaller than 72 and a composition containing said another metallic element.
Claim 13
Dependent Claim
104 words
A photomask suitable for inspecting a pattern formed thereon with electron beams comprising: a transparent glass substrate; a transparent electrically conductive film formed on said transparent glass substrate, said transparent electrically conductive film being formed of metal oxide of at least one metallic element having an atomic number equal to or smaller than 50; and a light shielding film of predetermined pattern provided on said transparent electrically conductive film, said pattern film being formed of at least one material selected from the group consisting of another metallic element having an atomic number not smaller than 72 and a composition containing said another metallic element.
Claim 14
Dependent Claim
24 words
A photomask according to claim 9, wherein said another metallic element is selected from the group consisting of gold, platinum, tungsten, tantalum and lead.
Claim 15
Dependent Claim
30 words
A photomask according to claim 10, wherein said metallic element of the conductive film is at least one metal selected from the group consisting of indium, tin, titanium and zinc.
Claim 16
Dependent Claim
36 words
A photomask according to claim 7 or 9, wherein the ratio of the electron backscattering coefficient of said pattern film to that of said transparent electrically conductive film is equal to or larger than about 1.3.
Claim 17
Dependent Claim
24 words
A photomask according to claim 9, wherein the thickness of said light shielding film is in a range of from 1500 to 2000 A.
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Cited
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-10 | 1986-07-12 | 1987-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-10 | 1990-07-12 | 1991-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-10 | 1994-07-12 | 1995-01-11 | $7700.00 | Window Closed / Lapsed |