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US 5,851,704 AGranted
Method and apparatus for the fabrication of semiconductor photomask
AssigneeMicron Technology, Inc.
InventorChristophe Pierrat
Life of this patent
Estimating the term…
Abstract
The present invention provides a method and apparatus of fabricating photomasks. The photomasks may be fabricated from a photomask blank structure having multiple layers. Upon patterning of these multiple layers by standard photolithographic processes, a photomask is created which is capable of phase-shifting incident light by various degrees, which may be 0.degree., 60.degree., 120.degree., and 180.degree..
Claims45
An apparatus for the fabrication of a semiconductor photomask, comprising:
- a substrate;
- at least three layers located above said substrate, at least two of said layers having chemical compositions different than said substrate;
- a top layer above said third layer;
- and
- openings within said top layer and at least two of said at least three layers such that light incident upon said photomask exits said photomask with at least three phase angles.
2 more elements
A photomask blank comprising:
- a substantially transparent substrate;
- a first phase-shifting layer disposed over the substrate, the first phase-shifting layer having a first thickness;
- a second phase-shifting layer disposed over the first phase-shifting layer, the second phase-shifting layer having a second thickness;
- a third phase-shifting layer disposed over the second phase-shifting layer, the third phase-shifting layer having a third thickness, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180.degree., and wherein at least two of the phase-shifting layers have chemical compositions different than the substrate;
- and
- an opaque layer disposed over the third phase-shifting layer.
3 more elements
A photomask comprising:
- a substantially transparent substrate;
- a first phase-shifting layer disposed over the substrate, the first phase-shifting layer having a first thickness;
- a second phase-shifting layer disposed over the first phase-shifting layer, the second phase-shifting layer having a second thickness;
- a third phase-shifting layer disposed over the second phase-shifting layer, the third phase-shifting layer having a third thickness, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180.degree., and wherein at least two of the phase-shifting layers have chemical compositions different than the substrate;
- and
- an opaque layer disposed over the third phase-shifting layer, the opaque layer having a plurality of openings formed therein, wherein a portion of at least one of the first, second, and third layers is removed underlying selected ones of the plurality of the openings.
3 more elements
A photomask blank comprising:
- a substantially transparent substrate;
- a first phase-shifting layer disposed over the substrate, the first phase-shifting layer having a first thickness;
- a second phase-shifting layer disposed over the first phase-shifting layer, the second phase-shifting layer having a second thickness, the first phase-shifting layer acting as an etch stop for the second phase-shifting layer;
- a third phase-shifting layer disposed over the second phase-shifting layer, the third phase-shifting layer having a third thickness, the second phase-shifting layer acting as an etch stop for the third phase-shifting layer, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180.degree.;
- and
- an opaque layer disposed over the third phase-shifting layer.
3 more elements
A photomask comprising:
- a substantially transparent substrate;
- a first phase-shifting layer disposed over the substrate, the first phase-shifting layer having a first thickness;
- a second phase-shifting layer disposed over the first phase-shifting layer, the second phase-shifting layer having a second thickness, the first phase-shifting layer acting as an etch stop for the second phase-shifting layer;
- a third phase-shifting layer disposed over the second phase-shifting layer, the third phase-shifting layer having a third thickness, the second phase-shifting layer acting as an etch stop for the third phase-shifting layer, wherein a sum of the first, second, and third thicknesses substantially corresponds to a phase shift of about 180.degree.;
- and
- an opaque layer disposed over the third phase-shifting layer, the opaque layer having a plurality of openings formed therein, wherein a portion of at least one of the first, second, and third layers is removed underlying selected ones of the plurality of the openings.
3 more elements
Dependencies are inferred from the claim text.