Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
127 words
A method of modifying a lithographic exposure pattern so as to make the exposure pattern less sensitive to proximity effect, the exposure pattern consisting of a plurality of shapes, comprising the steps of: notionally breaking the shapes of the lithographic exposure pattern into perimeter parts having a width on the order of the exposure pattern minimum linewidth and central parts, each central part being completely surrounded by a perimeter part; and modifying the exposure pattern by setting back the edges of each central part away from the perimeter part which surrounds it, thereby forming a nominally unexposed band inside of and immediately adjacent to each perimeter part having a central part, the nominally unexposed band acting to reduce electron scattering outside of the perimeter part adjacent thereto.
Claim 2
Independent Claim
127 words
A method of modifying a lithographic exposure pattern so as to make the exposure pattern less sensitive to proximity effect, the exposure pattern consisting of a plurality of shapes, comprising the steps of: notionally breaking the shapes of the lithographic exposure pattern into perimeter parts having a width on the order of the exposure pattern minimum linewidth and central parts, each central part being completely surrounded by a perimeter part; and modifying the exposure pattern by setting back the edges of each central part away from the perimeter part which surrounds it, thereby forming a nominally unexposed band inside of and immediately adjacent to each perimeter part having a central part, the nominally unexposed band acting to reduce electron scattering outside of the perimeter part adjacent thereto.
Claim 3
Dependent Claim
79 words
A method as claimed in claim 1 comprising setting back the edges of each central part as far as possible consistent with ensuring that as the nominally unexposed bands formed thereby are each sufficiently narrow that upon direct exposure of a radiation sensitive layer to the modified exposure pattern, the nominally unexposed bands are exposed to electrons scattered from adjacent directly exposed parts and upon development thereof the nominally unexposed bands develop substantially as if each were directly exposed.
Claim 4
Dependent Claim
32 words
A method as claimed in claim 1 or 2, comprising edge biasing the lithographic exposure pattern before the shapes of the exposure pattern are notionally broken into perimeter parts and central parts.
Claim 5
Dependent Claim
35 words
A method as claimed in claim 1, 2 or 3, comprising notionally entirely removing central parts having a sufficiently narrow width so as to form nominally unexposed regions in place of the removed central parts.
Claim 6
Dependent Claim
33 words
A method as claimed in claim 4, wherein the entirely removed central parts have a width equal to or less than about twice the amount by which the pattern has been edge biased.
Claim 7
Dependent Claim
32 words
A method as claimed in claim 4, comprising setting back the edges of each central part having sufficient size therefor about twice the amount by which the pattern has been edge biased.
Claim 8
Dependent Claim
49 words
A method as claimed in claim 4, comprising, for central parts not entirely removed but also not sufficiently wide to have the edges thereof set back by about twice the edge bias amount, setting back the edges so that a remaining central part is formed of predetermined minimum width.
Claim 9
Dependent Claim
37 words
A method as claimed in claim 7, wherein the edges of central parts having a size larger than a predetermined size are set back more than twice the amount by which the pattern has been edge biased.
Claim 10
Independent Claim
91 words
A method as claimed in any one of claims 1 to 8, comprising, for central parts having a size larger than a predetermined size, further notionally breaking those parts into perimeter subparts having a width on the order of the exposure pattern minimum linewidth and central subparts, each central subpart being completely surrounded by a perimeter subpart, and setting back the edges of each central subpart are set back from the perimeter subpart surrounding it, thereby forming a further nominally unexposed band inside of and immediately adjacent to each perimeter subpart.
Claim 11
Dependent Claim
28 words
A method as claimed in claim 3 wherein the amount by which the edges of central parts are set back generally increases with size of the central part.
Claim 12
Independent Claim
32 words
A method as claimed in any one of claims 1 to 10, comprising edge biasing central parts having a size larger than a predetermined size more than perimeter parts are edge biased.
Claim 13
Independent Claim
23 words
A method as claimed in any one of claims 1 to 11, wherein the lithographic exposure pattern is an electron beam exposure pattern.