US5362940A
Expired / Lapsed
US
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Use of Fresnel zone plates for material processing
Assignee: LITEL INTERCONNECT Inc
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Filing: 1992-09-03
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Granted: 1994-11-08
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Expires: 2012-09-03
Abstract
Abstract The apparatus for machining and material processing includes an excimer laser and a Fresnel zone plate array (FZP) positioned parallel to the workpiece, with the distance between the FZP and the workpiece being the focal length of the FZP. For each hole to be formed on the workpiece a corresponding Fresnel zone is patterned onto the FZP. Each Fresnel zone may be patterned directly centered over the desired hole location or in high density patterns it may be located off-center from the hole with deflection being accomplished by the formation of finer circular arcs on the side of the Fresnel zone opposite the desired direction of deflection. A beam scanner is included to provide a more uniform illumination of the FZP by the laser beam. The scanning eliminates non-uniformity of intensity. The alignment mechanism uses a helium-neon laser, the beam from which is projected onto a surface relief grating on the workpiece. The reflected light from the surface relief grating is filtered to create interference fringes which, when aligned, provide maximum light intensity projected through a transmission grating on the Fresnel zone plate.
Inventors
- 👤 Bruce G. MacDonald
- 👤 Robert O. Hunter, Jr.
- 👤 Adlai H. Smith
- 👤 Clark C. Guest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:41
CPC Classifications
H; H05; H05K; H05K3/00; H05K3/0011; H05K3/0017; H05K3/0026; B; B23; B23K; B23K26/00; B23K26/02; B23K26/04; B23K26/042; B23K26/06; B23K26/064; B23K26/066; B23K26/067; B23K26/08; B23K26/082; B23K26/36; B23K26/38; B23K26/382; B23K26/384; B23K26/40; G; G02; G02B; G02B5/00; G02B5/18; G02B5/1876; G02B5/188; G03; G03H; G03H1/00; G03H1/0005; B23K2103/00; B23K2103/02; B23K2103/04; B23K2103/30; B23K2103/42; B23K2103/50; B23K2103/52; G03H2001/0094; G03H2222/00; G03H2222/33; G03H2222/36; H05K2203/00; H05K2203/05; H05K2203/0548; H05K2203/056; H05K2203/10; H05K2203/107
Claims Analysis
Total Claims: 45
Claim 1
Independent Claim
131 words
A method of processing a plurality of selected locations on a workpiece by projecting arbitrary working patterns onto said workpiece at preselected locations, said method comprising the steps of: providing a plate having an array of discrete diffractive regions, each discrete diffractive region focusing light incident on said plate at a discrete focal distance from said plate in an arbitrary working pattern corresponding to a selected discrete location on said workpiece; aligning said plate with respect to said workpiece for simultaneous focus of each discrete diffraction region in said arbitrary working pattern at one of said plurality of selected locations; and projecting an incident beam through said array of discrete diffractive regions on said plate whereby each said discrete diffractive region produces said arbitrary working pattern at each selected discrete location.
Claim 2
Independent Claim
131 words
A method of processing a plurality of selected locations on a workpiece by projecting arbitrary working patterns onto said workpiece at preselected locations, said method comprising the steps of: providing a plate having an array of discrete diffractive regions, each discrete diffractive region focusing light incident on said plate at a discrete focal distance from said plate in an arbitrary working pattern corresponding to a selected discrete location on said workpiece; aligning said plate with respect to said workpiece for simultaneous focus of each discrete diffraction region in said arbitrary working pattern at one of said plurality of selected locations; and projecting an incident beam through said array of discrete diffractive regions on said plate whereby each said discrete diffractive region produces said arbitrary working pattern at each selected discrete location.
Claim 3
Dependent Claim
32 words
A method as in claim 1 wherein the step of , providing a plate includes configuring said discrete diffractive region as a function of the Fourier transform of said arbitrary working pattern.
Claim 4
Dependent Claim
32 words
A method as in claim 1 wherein the step of providing a plate includes providing to at least two of said discrete diffractive optic regions differing focal lengths and differing focal directions.
Claim 5
Dependent Claim
27 words
A method as in claim 1 wherein the step of providing a plate includes providing phase delay media to at least one of said diffractive optic regions.
Claim 6
Dependent Claim
38 words
A method as, in claim 1 wherein the step of providing a plate includes providing at least one diffractive region with a projected arbitrary working pattern which is selected from a group including squares, polygons, and asymmetric shapes.
Claim 7
Dependent Claim
29 words
A method as in claim 1 wherein the step of providing a plate includes providing at least one said diffractive region partially overlapping a second adjacent diffractive optic region.
Claim 8
Dependent Claim
69 words
A method as in claim 1 wherein the step of providing a plate includes providing at least one discrete diffractive region having a plurality of rings each being separated by a width of radius R=√kλf where λ is a wavelength of said light, f is a focal length of said discrete diffractive region and k is an identification number of the ring for which the width is being determined.
Claim 9
Dependent Claim
38 words
A method as in claim 7 wherein the step of providing a plate includes determining the resolution for a fabrication of said at least one discrete diffractive region according to the width of the narrowest said ring √kλf-√(k-1)λf.
Claim 10
Dependent Claim
47 words
A method as in claim 1 wherein the step of providing a plate includes providing at least one discrete diffractive region by etching said plate to a depth of λ/4(n-1) where λ is a wavelength of said light and n is a refractive index of said plate.
Claim 11
Dependent Claim
67 words
A method as in claim 1 wherein the step of providing a plate includes the step of providing at least one discrete diffractive region having a plurality of rings in a quantity according to the equation K=R 2 /λf where R is a radius of said discrete diffractive region, λ is a wavelength of said light and f is a focal length of said discrete diffractive region.
Claim 12
Dependent Claim
44 words
A method as in claim 1 wherein the step of projecting includes deflecting a portion of said incident beam projected through at least one discrete diffractive region at an angle Θ from perpendicular at a center of said at least one discrete diffractive region.
Claim 13
Dependent Claim
53 words
A method as in claim 11 wherein the step of providing at least one discrete diffractive region includes determining according to said angle Θ a pitch of a plurality of rings of said at least one diffractive region according to the equation P=λ/2 sin Θ where k is a wavelength of said light.
Claim 14
Dependent Claim
22 words
A method as in claim 1 wherein the step of aligning said plate includes positioning said plate substantially parallel to said workpiece.
Claim 15
Dependent Claim
22 words
A method as in claim 1 wherein the step of projecting an incident processing beam includes the step of scanning said beam.
Claim 16
Dependent Claim
22 words
A method as in claim 1 wherein the step of providing a plate includes providing said discrete diffractive regions of same sizes.
Claim 17
Dependent Claim
24 words
A method as in claim 1 wherein the step of providing a plate includes providing discrete diffractive regions having alternating opaque and transparent regions.
Claim 18
Dependent Claim
19 words
A method as in claim 1 wherein said discrete diffractive regions project constructively-interfering portions of said arbitrary working pattern.
Claim 19
Dependent Claim
19 words
A method as in claim 1 wherein said discrete diffractive regions project destructively-interfering portions of said arbitrary working pattern.
Claim 20
Dependent Claim
25 words
A method as in claim 1 wherein the step of projecting comprises projecting an incident processing beam through a plurality of diffractive optic regions simultaneously.
Claim 21
Independent Claim
74 words
An apparatus for processing a plurality of selected locations on a workpiece by projecting arbitrary working patterns onto said workpiece at preselected locations, said apparatus comprising: a light source for generating an incident processing beam; and a plate having an array of diffractive regions, each diffractive region focusing said incident processing beam at a discrete focal distance from said plate in an arbitrary working pattern corresponding to a discrete preselected location on said workpiece.
Claim 22
Independent Claim
74 words
An apparatus for processing a plurality of selected locations on a workpiece by projecting arbitrary working patterns onto said workpiece at preselected locations, said apparatus comprising: a light source for generating an incident processing beam; and a plate having an array of diffractive regions, each diffractive region focusing said incident processing beam at a discrete focal distance from said plate in an arbitrary working pattern corresponding to a discrete preselected location on said workpiece.
Claim 23
Dependent Claim
24 words
An apparatus as in claim 20 wherein said diffractive region is configured as a function of the Fourier transform of said arbitrary working pattern.
Claim 24
Dependent Claim
24 words
An apparatus as in claim 20 wherein at least two diffractive optic regions within said array have differing focal lengths and differing focal directions.
Claim 25
Dependent Claim
17 words
An apparatus as in claim 20 wherein at least one diffractive region includes transmissive phase delay media.
Claim 26
Dependent Claim
31 words
An apparatus as in claim 20 wherein said at least one diffractive region has a projected arbitrary working pattern which is selected from a group including squares, polygons, and asymmetric shapes.
Claim 27
Dependent Claim
19 words
An apparatus as in claim 20 wherein at least one diffractive region partially overlaps a second adjacent diffractive region.
Claim 28
Dependent Claim
60 words
An apparatus as in claim 20 wherein at least one diffractive region comprises a plurality of rings, said rings being separated by a width of radius √ kλf where λ is a wavelength of said light, f is a focal length of said diffractive region and k is the number of the ring for which said width is being determined.
Claim 29
Dependent Claim
39 words
An apparatus as in claim 20 wherein at least one diffractive region is etched into said plate to a depth of λ/4(n-1) where λ is a wavelength of said light and n is a refractive index of said plate.
Claim 30
Dependent Claim
54 words
An apparatus as in claim 20 wherein at least one diffractive region has a plurality of rings in a quantity according to the equation K=R 2 /λf where R is a radius of said discrete diffractive region, λ is a wavelength of said light and f is a focal length of said diffractive region.
Claim 31
Dependent Claim
32 words
An apparatus as in claim 20 wherein at least one diffractive region deflects said incident beam at an angle 8 from perpendicular to a center of said at least one diffractive region.
Claim 32
Dependent Claim
41 words
An apparatus as in claim 29 wherein at least one diffractive region comprises a plurality of rings having a pitch determined according to said angle Θ according to the equation P=λ/2 sin Θ where λ is a wavelength of said light.
Claim 33
Dependent Claim
18 words
An apparatus as in claim 20 wherein the diffractive regions of said array are of a same size.
Claim 34
Dependent Claim
16 words
An apparatus as in claim 20 wherein said diffractive region comprises alternating opaque and transparent rings.
Claim 35
Dependent Claim
18 words
An apparatus as in claim 20 wherein said diffractive region projects constructively-interfering portions of said arbitrary working pattern.
Claim 36
Dependent Claim
18 words
An apparatus as in claim 20 wherein said diffractive region projects destructively-interfering portions of said arbitrary working pattern.
Claim 37
Dependent Claim
23 words
An apparatus as in claim 20 wherein said array of diffractive regions focuses a plurality of arbitrary working patterns onto said workpiece simultaneously.
Claim 38
Independent Claim
130 words
A method of processing a plurality of selected locations on a workpiece by simultaneously focusing a plurality of beams carrying an arbitrary working pattern onto said workpiece, said method which comprises: projecting a reference beam of light from a reference laser through a plurality of first alignment marks on a transparent plate located above said workpiece; aligning said plurality of first alignment marks with a plurality of second alignment marks on said workpiece; and projecting an incident processing beam through a diffractive optic array having a plurality of diffractive regions, one diffractive region corresponding to each selected location on said workpiece for focussing an arbitrary working pattern thereon, thereby creating a plurality of processing beams, each carrying a corresponding arbitrary working pattern, one processing beam corresponding to each selected location.
Claim 39
Independent Claim
130 words
A method of processing a plurality of selected locations on a workpiece by simultaneously focusing a plurality of beams carrying an arbitrary working pattern onto said workpiece, said method which comprises: projecting a reference beam of light from a reference laser through a plurality of first alignment marks on a transparent plate located above said workpiece; aligning said plurality of first alignment marks with a plurality of second alignment marks on said workpiece; and projecting an incident processing beam through a diffractive optic array having a plurality of diffractive regions, one diffractive region corresponding to each selected location on said workpiece for focussing an arbitrary working pattern thereon, thereby creating a plurality of processing beams, each carrying a corresponding arbitrary working pattern, one processing beam corresponding to each selected location.
Claim 40
Independent Claim
103 words
An apparatus for processing a workpiece by focussing a plurality of beams carrying arbitrary working patterns onto selected areas of said workpiece, one beam corresponding to each selected area, said apparatus comprising: a light source for generating an incident processing beam having at least one wavefront; and a diffractive optic array having a plurality of diffractive regions, each diffractive region corresponding to one said selected area, said wavefront impinging upon said diffractive optic array causing one said beam to be projected from each said diffractive region, said beam being focused on and carrying its arbitrary working pattern to its corresponding said selected area.
Claim 41
Independent Claim
103 words
An apparatus for processing a workpiece by focussing a plurality of beams carrying arbitrary working patterns onto selected areas of said workpiece, one beam corresponding to each selected area, said apparatus comprising: a light source for generating an incident processing beam having at least one wavefront; and a diffractive optic array having a plurality of diffractive regions, each diffractive region corresponding to one said selected area, said wavefront impinging upon said diffractive optic array causing one said beam to be projected from each said diffractive region, said beam being focused on and carrying its arbitrary working pattern to its corresponding said selected area.
Claim 42
Independent Claim
133 words
A method of processing a plurality of selected locations on a workpiece by projecting arbitrary working patterns onto said workpiece at preselected locations, said method comprising the steps of: providing a plate having an array of discrete diffractive regions, each discrete diffractive region focusing light incident on said plate at a discrete focal distance from said plate in an arbitrary working pattern corresponding to a selected discrete location on said workpiece; aligning said plate with respect to said workpiece for simultaneous focus of each discrete diffraction region in said arbitrary working pattern at one of said plurality of selected locations; and continuously scanning an incident beam sequentially through said array of discrete diffractive regions on said plate whereby each said discrete diffractive region produces said arbitrary working pattern at each selected discrete location.
Claim 43
Independent Claim
133 words
A method of processing a plurality of selected locations on a workpiece by projecting arbitrary working patterns onto said workpiece at preselected locations, said method comprising the steps of: providing a plate having an array of discrete diffractive regions, each discrete diffractive region focusing light incident on said plate at a discrete focal distance from said plate in an arbitrary working pattern corresponding to a selected discrete location on said workpiece; aligning said plate with respect to said workpiece for simultaneous focus of each discrete diffraction region in said arbitrary working pattern at one of said plurality of selected locations; and continuously scanning an incident beam sequentially through said array of discrete diffractive regions on said plate whereby each said discrete diffractive region produces said arbitrary working pattern at each selected discrete location.
Claim 44
Dependent Claim
23 words
The process of claim 38 and wherein said continuously scanning step includes: continuously scanning said beam across a narrow region on said plate.
Claim 45
Dependent Claim
27 words
The process of claim 39 and wherein said continuously scanning step includes: continuously scanning said beam across narrow regions of said plate with said scans overlapping themselves.
References Cited (Backward Citations)
US4909818A
Cited
DE4106423A1
Cited
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