EP0265658A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
High energy laser mask and method of making same
Assignee: International Business Machines Corp
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Filing: 1987-09-18
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Granted: —
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Expires: 2007-09-18
Abstract
Abstract The present invention is a mask and methods for making masks for use with a laser projection etching system. The unique mask is able to withstand the fluences of the high energy and high power lasers used without degrading. Specifically, the new projection etching masks are fabricated of patterned multiple dielectric layers having alternating high and low indices of refraction on a UV grade synthetic fused silica substrate in order to achieve maximum reflectivity of the laser energy in the opaque areas and maximum transmissivity of the laser energy in the transparent area of the mask.
Inventors
- 👤 Steven James Kirch
- 👤 John Robert Lankard
- 👤 John Hames Ritsko
- 👤 Kurt Alan Smith
- 👤 James Louis Speidell
- 👤 James Tien-Cheng Yeh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 15:05
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/54; G03F1/58; G03F1/22; G03F1/24
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
46 words
A transmission mask for use with electromagnetic radiation sources, comprising a substantially transparent substrate covered with a patterned coating, characterized in that the coating is a reflective multilayer structure comprised of at least two dielectric materials with different index of refraction arranged in an alternating sequence.
Claim 2
Dependent Claim
46 words
A transmission mask for use with electromagnetic radiation sources, comprising a substantially transparent substrate covered with a patterned coating, characterized in that the coating is a reflective multilayer structure comprised of at least two dielectric materials with different index of refraction arranged in an alternating sequence.
Claim 3
Dependent Claim
31 words
The mask of claim 1, wherein the reflectivity of the coating is selected such that the coating withstands applied radiation energy densities of at least several hundred millijoules per centimeter squared.
Claim 4
Dependent Claim
50 words
The mask of claim 1 or 2, wherein the dielectric material with the higher index of refraction is selected from a group containing hafnium oxide, scandium oxide, aluminum oxide and thallium floride, and wherein the lower index material is selected from a group containing silicon dioxide, magnesium fluoride and cryolite.
Claim 5
Dependent Claim
19 words
The mask of anyone of the preceeding claims, wherein the substrate is comprised of UV grade synthetic fused silica.
Claim 6
Dependent Claim
13 words
Use of the mask of anyone of the preceeding claims for projection printing.
Claim 7
Dependent Claim
118 words
Method of making a transmission mask used with electromagnetic radiation sources, providing in a first step a substrate substantially transparent to said radiation, and further being characterized by the steps of: selecting two dielectric materials differing in their index of refraction, depositing an alternating sequence of layers of said dielectric materials, adjusting during deposition the thickness of each higher index dielectric layer to a quarter of the wavelength of the used electromagnetic radiation, depositing a photosensitive masking material on the surface of the top layer, exposing and removing the photosensitive material in the areas in which the dielectric is to be removed, removing the exposed dielectric coating layers to expose the underlying transparent substrate, removing the photosensitive material.
Claim 8
Dependent Claim
118 words
Method of making a transmission mask used with electromagnetic radiation sources, providing in a first step a substrate substantially transparent to said radiation, and further being characterized by the steps of: selecting two dielectric materials differing in their index of refraction, depositing an alternating sequence of layers of said dielectric materials, adjusting during deposition the thickness of each higher index dielectric layer to a quarter of the wavelength of the used electromagnetic radiation, depositing a photosensitive masking material on the surface of the top layer, exposing and removing the photosensitive material in the areas in which the dielectric is to be removed, removing the exposed dielectric coating layers to expose the underlying transparent substrate, removing the photosensitive material.
Claim 9
Dependent Claim
16 words
The method of claim 6, wherein the exposed dielectric coating layers are removed by ion milling.
Claim 10
Dependent Claim
108 words
Method of making a transmission mask used with electromagnetic radiation sources, providing in a first step a substrate substantially transparent to said radiation, and further being characterized by the steps of: applying a lift-off mask by depositing a layer of photosensitive material, selectively exposing said material and removing the exposed parts to reveal the underlying substrate, selecting two dielectric materials differing in their index of refraction, depositing an alternating sequence of layers of said dielectric materials, adjusting during deposition the thickness of each higher index dielectric layer to a quarter of the wavelength of the used electromagnetic radiation, removing the lift-off mask and the dielectric material deposited thereon.
Claim 11
Dependent Claim
108 words
Method of making a transmission mask used with electromagnetic radiation sources, providing in a first step a substrate substantially transparent to said radiation, and further being characterized by the steps of: applying a lift-off mask by depositing a layer of photosensitive material, selectively exposing said material and removing the exposed parts to reveal the underlying substrate, selecting two dielectric materials differing in their index of refraction, depositing an alternating sequence of layers of said dielectric materials, adjusting during deposition the thickness of each higher index dielectric layer to a quarter of the wavelength of the used electromagnetic radiation, removing the lift-off mask and the dielectric material deposited thereon.
Claim 12
Independent Claim
54 words
The method of anyone of the claims 6 to 8, wherein the higher index of refraction dielectric coating material is being selected from a group containing hafnium oxide, scandium oxide, aluminum oxide, thallium fluoride, and wherein the lower index of refraction material is being selected from a group containing silicon dioxide, magnesium fluoride, cryolite.
Claim 13
Independent Claim
21 words
The method of anyone of the claims 6 to 9, wherein the substrate is comprised of UV grade synthetic fused silica.
Claim 14
Independent Claim
89 words
The method of anyone or more of the claims 6 to 10 further characterized in comprising the steps: applying a light beam incident to the surface of said sequence of layers at an angle whose tangent is equal to the index of refraction of said substrate; polarizing said light beam such that the beam will be reflected at the interfaces between said two dielectric coating materials but will pass into said substrate; monitoring the reflexted beam; and halting the removing step when said incident beam is no longer reflected.
References Cited (Backward Citations)
No citation records indexed.
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