US3698808A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical masking device
Assignee: France Telecom R&D SA
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Filing: 1971-03-01
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Granted: 1972-10-17
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Expires: 1991-03-01
Abstract
Abstract The device is intended for optically masking a photosensitive layer on a wafer by means of a mask. It comprises a first and a second lens each having a large numerical aperture and separated by a gap. A mask holder is located in the focal plane of the first lens located on its side opposite that of the gap, and a wafer holder in the focal plane of the second lens located on its side opposite that of the gap. A source of ultraviolet radiation produces a beam aligned with the first lens axis and a source of visible light produces a beam rectangular to said axis. A semireflecting plane member located in the gap provided between the two lenses and at 45* on the axis of the first lens transmits one of the beams and reflects the other beam along the second lens axis. A first possible arrangement is such that the semireflecting member is in a space where both beams are made of parallel rays. In another possible arrangement, a concave mirror reflecting the light transmitted through the first lens and the semireflecting member is provided. Position adjustment means are provided for shifting the wafer holder in the plane perpendicular to the second lens axis and superimposing the image of the wafer through the first and second lenses and the mask. The adjustment is effected with the aid of the visible light source, the ultraviolet light source being used for photogravure purposes.
Inventors
- 👤 Jean R Delmas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:33
CPC Classifications
H; H10; H10P; H10P95/00; G; G03; G03F; G03F9/00; G03F9/70
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
231 words
A device for optically masking an ultra-violet light photosensitive layer on a wafer by means of a mask, said device comprising in the following order a first lens, a gap and a second lens, both lenses having a large numerical aperture, a mask holder in the focal plane of the first lens located on its side farther from said gap, a wafer holder in the focal plane of the second lens located on its side farther from said gap, a source of ultra violet radiation and a source of visible light alternatively and at will producing rectangular visible and ultraviolet beams, the ultraviolet beam being aligned with the first lens axis, a semi-reflecting plane member located in said gap and oriented at 45* relatively to the axes of said lenses, said member transmitting one of said beams and reflecting the other of said beams in a common direction along said second lens axis, means for adjusting the position of said second lens along its axis so as to focus the image of said mask upon said wafer and means for shifting said wafer holder in the plane perpendicular to the second lens axis and superimposing The image of the wafer seen through said first and second lens on said mask, whereby an ultraviolet masking pattern which is the image of the mask through the lenses is formed on the photosensitive layer.
Claim 2
Independent Claim
231 words
A device for optically masking an ultra-violet light photosensitive layer on a wafer by means of a mask, said device comprising in the following order a first lens, a gap and a second lens, both lenses having a large numerical aperture, a mask holder in the focal plane of the first lens located on its side farther from said gap, a wafer holder in the focal plane of the second lens located on its side farther from said gap, a source of ultra violet radiation and a source of visible light alternatively and at will producing rectangular visible and ultraviolet beams, the ultraviolet beam being aligned with the first lens axis, a semi-reflecting plane member located in said gap and oriented at 45* relatively to the axes of said lenses, said member transmitting one of said beams and reflecting the other of said beams in a common direction along said second lens axis, means for adjusting the position of said second lens along its axis so as to focus the image of said mask upon said wafer and means for shifting said wafer holder in the plane perpendicular to the second lens axis and superimposing The image of the wafer seen through said first and second lens on said mask, whereby an ultraviolet masking pattern which is the image of the mask through the lenses is formed on the photosensitive layer.
Claim 3
Dependent Claim
47 words
A device for optically masking a photosensitive layer as set forth in claim 1 in which the mask is to the same scale as the ultraviolet masking pattern, the two lenses are identical and the magnification of the objective formed by said two lenses is minus one.
Claim 4
Dependent Claim
23 words
A device for optically masking a photosensitive layer as set forth in claim 1, in which the first and second lenses are coaxial.
Claim 5
Dependent Claim
40 words
A device for optically masking a photosensitive layer as set forth in claim 1 in which the wafer holder comprises at least three point abutments and a pneumatic diaphragm for supporting the wafer and engaging the same against said abutments.
Claim 6
Dependent Claim
25 words
A device for optically masking a photosensitive layer as set forth in claim 1 comprising means for retracting the semireflecting member from the beam paths.
Claim 7
Independent Claim
283 words
A device for optically masking an ultra-violet light photosensitive layer on a wafer by means of a mask, said device comprising in the following order a first lens, a gap and a second lens, both lenses having a large numerical aperture and having mutually perpendicular axes, a mask holder in the focal plane of said first lens, a wafer holder in the focal plane of said second lens located on its side farther from said gap, a source of ultraviolet radiation producing an ultraviolet radiation beam aligned with said first lens axis, a source of visible light producing a visible light beam aligned with said second lens axis, said sources operating alternatively at will, a semireflecting plane member located in said gap near the junction point of said lens axes and inclined at 45* with respect to said axes, said member transmitting one of said beams and reflecting the other of said beams in a common direction along said second lens axis, means for adjusting the position of said second lens along its axis so as focus the image of said mask upon said wafer, means for shifting said wafer holder in the plane perpendicular to said second lens axis and superimposing in visible light the image of the wafer through said first and second lenses and the mask, whereby an ultraviolet masking pattern which is the image of the mask through the lenses is formed on said photosensitive layer, and a concave mirror located on the first lens axis for reflecting towards said semireflecting member the part of said ultraviolet light beam which is transmitted through said member without reflection, said mirror having its axis substantially coinciding with said first lens axis.
Claim 8
Independent Claim
283 words
A device for optically masking an ultra-violet light photosensitive layer on a wafer by means of a mask, said device comprising in the following order a first lens, a gap and a second lens, both lenses having a large numerical aperture and having mutually perpendicular axes, a mask holder in the focal plane of said first lens, a wafer holder in the focal plane of said second lens located on its side farther from said gap, a source of ultraviolet radiation producing an ultraviolet radiation beam aligned with said first lens axis, a source of visible light producing a visible light beam aligned with said second lens axis, said sources operating alternatively at will, a semireflecting plane member located in said gap near the junction point of said lens axes and inclined at 45* with respect to said axes, said member transmitting one of said beams and reflecting the other of said beams in a common direction along said second lens axis, means for adjusting the position of said second lens along its axis so as focus the image of said mask upon said wafer, means for shifting said wafer holder in the plane perpendicular to said second lens axis and superimposing in visible light the image of the wafer through said first and second lenses and the mask, whereby an ultraviolet masking pattern which is the image of the mask through the lenses is formed on said photosensitive layer, and a concave mirror located on the first lens axis for reflecting towards said semireflecting member the part of said ultraviolet light beam which is transmitted through said member without reflection, said mirror having its axis substantially coinciding with said first lens axis.
Claim 9
Dependent Claim
46 words
A device for optically masking a photosensitive layer as set forth in claim 6, in which said semireflecting member consists of a Lummer''s cube made of two prisms having in cross-section the shape of a rectangular isosceles triangle and placed side by side with each other.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-17 | 1976-04-17 | 1976-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-17 | 1980-04-17 | 1980-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-17 | 1984-04-17 | 1984-10-17 | $7700.00 | Window Closed / Lapsed |