Overcoat compositions and methods for photolithography
Topcoat compositions are provided that are suitably applied above a photoresist composition. Preferred topcoat compositions comprise a first polymer comprising first units comprising a reactive nitrogen-containing moiety spaced from the polymer backbone, wherein the nitrogen-containing moiety produces a basic cleavage product during lithographic processing of the photoresist composition.
1. A composition suitable for use in forming a layer over photoresist layer, the composition comprising:
a first polymer comprising:
first units comprising a reactive sulfamate moiety spaced from the polymer backbone, wherein the sulfamate moiety produces a basic cleavage product during lithographic processing of the photoresist composition, and
wherein an acid-labile group is interposed between the first polymer backbone and the reactive sulfamate moiety.
2. A composition of claim 1 wherein the first polymer further comprises second units distinct from the first units, the second units each comprising 1) a reactive sulfamate moiety and 2) an acid-labile group.
3. A composition of claim 1 wherein the sulfamate moiety is spaced from the polymer by optionally substituted alkylene, optionally substituted carbon alicyclic, optionally substituted heteroalicyclic, optionally substituted carbocyclic aryl or optionally substituted heteroaryl.
4. A composition of claim 1 wherein the first polymer further comprises:
third units that 1) comprise one or more hydrophobic groups and 2) are distinct from both of the first and second units.
5. A method for processing a photoresist composition, comprising:
(a) applying a layer of a photoresist composition on a substrate;
(b) above the photoresist composition layer, applying a layer of a composition of claim 1 to form a topcoat layer;
(c) patternwise exposing the topcoat layer and photoresist layer to activating radiation; and
(d) developing the exposed photoresist composition layer to provide a photoresist relief image.
6. The method of claim 5 wherein the exposed photoresist and topcoat layers are developed with an organic solvent composition that selectively removes unexposed portions of the photoresist composition layer to provide the photoresist relief image.
7. The composition of claim 1 wherein the composition does not contain an acid generator compound.
8. A coated substrate, comprising:
(a) a substrate having a photoresist composition layer thereon; and
(b) above the photoresist composition layer, a layer of a composition comprising:
a first polymer comprising:
first units comprising a reactive sulfamate moiety spaced from the polymer backbone, wherein the sulfamate moiety produces a basic cleavage product during lithographic processing of the photoresist composition, and
wherein an acid-labile group is interposed between the first polymer backbone and the reactive sulfamate moiety.