Method of enhancing the contrast of images and materials therefor

Claim 1

A method of producing in a layer of photoresist having a predetermined contrast threshold a pattern representing an enhancement in contrast of a projected image of an object with opaque and transparent regions having a contrast less than said predetermined contrast threshold when light of a predetermined wavelength to which said layer of photoresist is sensitive is utilized to form said projected image of said object, comprising providing said layer of photoresist having a first thickness, providing said object, providing between said object and said layer of photoresist and adjacent a surface of said layer of photoresist a layer of photobleachable material of a second thickness including a photobleachable compound selected from the aryl nitrone class of compounds, said photobleachable compound being sensitive to said predetermined wavelength of light, said photobleachable compound having an extinction coefficient to molecular weight ratio in the unbleached state greater than about 10 liters per gram-cm, the ratio of the extinction coefficient for the unbleached state to the extinction coefficient for the bleached state of said photobleachable compound being greater than about 10, said layer of photobleachable material having the characteristic that when light of said predetermined wavelength is projected through said object onto said layer of photobleachable material the optical density of said layer of photobleachable material is reduced in direct proportion to the dosage of light of said predetermined wavelength incident thereon, whereby the integrated contrast of the image of said object transmitted by said layer of photobleachable material increases with dosage of light transmitted thereby, reaches a maximum value and thereafter decreases, said maximum value of integrated contrast being greater than said perdetermined contrast threshold, said first thickness and sensitivity of said layer of photoresist being selected such that said layer of photoresist is fully exposed by a dosage of light in a predetermined range transmitted by said layer of photobleachable material and produces an integrated contrast in the transmitted image greater than said predetermined contrast threshold, projecting light of said predetermined wavelength through said object for a time to provide said dosage in said predetermined range transmitted through said layer of photobleachable material, removing said layer of photobleachable material and developing said layer of photoresist, whereby said pattern representing said enhancement in contrast of said image of said object is produced in said layer of photoresist.

Claim 2

A method of producing in a layer of photoresist having a predetermined contrast threshold a pattern representing an enhancement in contrast of a projected image of an object with opaque and transparent regions having a contrast less than said predetermined contrast threshold when light of a predetermined wavelength to which said layer of photoresist is sensitive is utilized to form said projected image of said object, comprising providing said layer of photoresist having a first thickness, providing said object, providing between said object and said layer of photoresist and adjacent a surface of said layer of photoresist a layer of photobleachable material of a second thickness including a photobleachable compound selected from the aryl nitrone class of compounds, said photobleachable compound being sensitive to said predetermined wavelength of light, said photobleachable compound having an extinction coefficient to molecular weight ratio in the unbleached state greater than about 10 liters per gram-cm, the ratio of the extinction coefficient for the unbleached state to the extinction coefficient for the bleached state of said photobleachable compound being greater than about 10, said layer of photobleachable material having the characteristic that when light of said predetermined wavelength is projected through said object onto said layer of photobleachable material the optical density of said layer of photobleachable material is reduced in direct proportion to the dosage of light of said predetermined wavelength incident thereon, whereby the integrated contrast of the image of said object transmitted by said layer of photobleachable material increases with dosage of light transmitted thereby, reaches a maximum value and thereafter decreases, said maximum value of integrated contrast being greater than said perdetermined contrast threshold, said first thickness and sensitivity of said layer of photoresist being selected such that said layer of photoresist is fully exposed by a dosage of light in a predetermined range transmitted by said layer of photobleachable material and produces an integrated contrast in the transmitted image greater than said predetermined contrast threshold, projecting light of said predetermined wavelength through said object for a time to provide said dosage in said predetermined range transmitted through said layer of photobleachable material, removing said layer of photobleachable material and developing said layer of photoresist, whereby said pattern representing said enhancement in contrast of said image of said object is produced in said layer of photoresist.

Claim 6

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist and positioned on the surface of the photoresist layer.

Claim 7

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist and positioned on the surface of the photoresist layer.

Claim 8

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder wherein the photobleachable layer is positioned on the surface of a thin conformal layer of neutral material which is on the surface of the photoresist layer.

Claim 9

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder wherein the photobleachable layer is positioned on the surface of a thin conformal layer of neutral material which is on the surface of the photoresist layer.

Claim 10

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist wherein the photobleachable compound is photofragmentable.

Claim 11

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist wherein the photobleachable compound is photofragmentable.

Claim 12

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist wherein the photobleachable compound is photoisomerizable.

Claim 13

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist wherein the photobleachable compound is photoisomerizable.

Claim 14

A method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an aerial image of ultraviolet radiation of predetermined wavelength of the pattern onto the photoresist through a photobleachable layer in conformal relationship with the photoresist layer, the photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound sensitive to said predetermined wavelength and a binder.

Claim 15

A method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an aerial image of ultraviolet radiation of predetermined wavelength of the pattern onto the photoresist through a photobleachable layer in conformal relationship with the photoresist layer, the photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound sensitive to said predetermined wavelength and a binder.

Claim 17

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist wherein the photobleachable compound is an aryl nitrone.

Claim 18

The method for producing a pattern in a layer of ultraviolet radiation sensitive photoresist which comprises projecting an ultraviolet radiation aerial image of said pattern through a photobleachable layer comprising an ultraviolet radiation sensitive photobleachable organic compound and a binder, said layer being in conformal relationship with the photoresist wherein the photobleachable compound is an aryl nitrone.