Abstract A semitransparent photolithography mask, i.e., one transparent to a portion of the visible light spectrum, is achieved by electron and ion bombardment of a positive photoresist. This bombardment is performed after the desired photoresist pattern is defined by the sequential steps of depositing, baking and developing the photoresist (14) on a light transparent substrate (15). In the preferred embodiment, the electron and ion bombardment is accomplished in a predominantly nitrogen atmosphere within a sputtering chamber using indium tin oxide as the sputtering target. As a result of the bombardment, the photoresist is converted into a material which is opaque to only the ultraviolet portion of the light spectrum.
A method of producing photolithography masks, transparent to a portion of the visible spectrum, comprising the steps of: (a) depositing positive photoresist (14) onto a light transparent substrate (15) to achieve a uniform coating; (b) baking the deposited photoresist to fix the same; (c) selectively exposing said photoresist to ultraviolet radiation; (d) developing said photoresist to remove the exposed portions thereof and further CHARACTERIZED BY the step of (e) bombarding said photoresist with electrons and ions in a predominantly nitrogen atmosphere to convert said photoresist to a material opaque to ultraviolet light.
Claim 2
Independent Claim
92 words
A method of producing photolithography masks, transparent to a portion of the visible spectrum, comprising the steps of: (a) depositing positive photoresist (14) onto a light transparent substrate (15) to achieve a uniform coating; (b) baking the deposited photoresist to fix the same; (c) selectively exposing said photoresist to ultraviolet radiation; (d) developing said photoresist to remove the exposed portions thereof and further CHARACTERIZED BY the step of (e) bombarding said photoresist with electrons and ions in a predominantly nitrogen atmosphere to convert said photoresist to a material opaque to ultraviolet light.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said bombardment is performed in a sputtering chamber.
Claim 4
Dependent Claim
30 words
The method of claim 2 wherein indium tin oxide is sputtered in a chamber under a vacuum of 6×10 -3 torr using 500 watts of RF power for five minutes.
Claim 5
Dependent Claim
34 words
The method of claim 3 further including the step of sputtering a layer of chromium on the light transparent substrate prior to the step of depositing said positive photoresist onto said light transparent substrate.