EP0020132A2
Expired / Lapsed
EP
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Method of and apparatus for producing a diffracting means
Assignee: Massachusetts Institute of Technology
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Filing: 1980-05-28
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Granted: —
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Expires: 2000-05-28
Abstract
Abstract Soft carbon-K X-rays (38) are used to expose a PMMA photoresist (31) on an oxide layer (32) of a silicon substrate (33) through a parent mask (30) separated a distance S from the resist by a spacer (34). The parent mask slits (12, 17) define a pattern of spatial period p, to establish an intensity pattern of period p/n at the resist with S = p 2 /nλ, where λ is the wavelength of the incident radiation and λ << p.
Inventors
- 👤 Dale C. Flanders
- 👤 Henry I. Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:08
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70216; G03F7/70325; G02; G02B; G02B5/00; G02B5/18; G02B5/1847; G02B5/1857; G03F7/20; G03F7/2037; G03F7/2039
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
81 words
L. A method of producing diffracting means such as diffraction gratings, the method including exposing 3 substrate (33) to radiant energy (38) of wavelength λ through a parent mask (30) having a pattern of slits (12, 17) of spatial period p, the parent mask (30) being spaced from the substrate (33) a distance S substantially equal to p 2 /nλ where n is an integer greater than one, to provide an intensity pattern of spatial period p/n on the substrate (33).
Claim 2
Dependent Claim
12 words
A method according to claim 1, wherein the radiant energy is X-rays.
Claim 3
Dependent Claim
13 words
A method according,to claim 1, wherein the radiant energy is of optical wavelength.
Claim 4
Dependent Claim
14 words
A method according to claim 1, wherein the radiant energy is ultraviolet radiant energy.
Claim 5
Independent Claim
22 words
A method according to any of claims 1 to 4, the width of each of the slits (12, 17) is ≤ p/2n.
Claim 6
Independent Claim
37 words
A method according to any of claims 1 to 5 wherein the spatial period of the pattern of slits on the parent mask (30) varies as a function of position, whereby so called quasi-periodic gratings are formed.
Claim 7
Dependent Claim
30 words
A method according to claim 1, wherein the parent mask has a pattern of apertures, the widths of which are less than one half of the local spatial period, p.
Claim 8
Dependent Claim
39 words
A method according to claim 1, for producing a Fresnel zone pattern, wherein the parent mask has a pattern of Fresnel-zone concentric circular apertures, the widths of which are less than one half of the local spatial period p.
Claim 9
Independent Claim
72 words
A method for producing diffracting means such as gratings, grids and Fresnel-zone patterns, the method including exposing a substrate to radiant energy of wavelength X through a parent mask having a pattern of apertures, wherein the thickness of the material between the parent mask apertures is such that radiation passing through it suffers a differential phase shift that is an odd multiple of π radians relative to radiation passing through the apertures.
Claim 10
Dependent Claim
60 words
Apparatus for use in a method according to any of claims 1 to 8, the apparatus comprising a substrate (33) carrying a radiation sensitive resist (31) on the surface thereof, a parent diffraction mask (30) and means (34) for supporting the parent mask (30) a distance S from the substrate to be exposed to radiant energy passed through the mask.
Claim 11
Dependent Claim
10 words
Apparatus according to claim 10, wherein the resist is PMMA.
References Cited (Backward Citations)
No citation records indexed.
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