Mask for projecting a structure pattern onto a semiconductor substrate
View Patent ↗A mask is configured for projecting a structure pattern onto a semiconductor substrate in an exposure unit. The exposure unit has a minimum resolution limit for projecting the structure pattern onto the semiconductor substrate. The mask has a substrate, at least one raised first structure element on the substrate which has a lateral extent which is at least the minimum lateral extent that can be attained by the exposure unit, a configuration second raised structure elements which are arranged in an area surrounding the at least one first structure element on the substrate in the form of a matrix with a row spacing and a column spacing, whose shape and size are essentially identical to one another, and which have a respective lateral extent that is less than the minimum resolution limit of the exposure unit.
1. A mask for projecting a structure pattern onto a semiconductor substrate in an exposure unit, the exposure unit having a minimum resolution limit for projecting the structure pattern onto the semiconductor substrate, the mask comprising:
a substrate;
at least one raised first structure element on said substrate, said first structure element having a lateral extent amounting to at least the minimum resolution limit, said first structure element formed of a first layer and a second layer, said first layer and said second layer selected from the group consisting of opaque layers and semitransparent layers;
a configuration of raised second structure elements, said second structure elements:
being disposed in a vicinity of said first structure element on said substrate and arranged in a matrix with a row spacing and a column spacing;
being formed by only said first layer;
having a substantially identical shape and size; and
having a respective lateral extent less than the minimum resolution limit, so that the structure configuration cannot be transferred to a photosensitive resist layer formed on the semiconductor substrate.
2. The mask according to claim 1 , wherein said at least one raised first structure element is surrounded by said matrix of said second structure elements.
3. The mask according to claim 1 , wherein said at least one raised first structure element is disposed with a spacing distance from each of said raised second structure elements in said matrix.
4. The mask according to claim 1 , wherein at least one of said second structure elements formed of said first layer being an opaque layer.
5. The mask according to claim 1 , wherein at least one of said second structure elements formed of said first layer being a semitransparent layer.
6. The mask according to claim 1 , wherein:
said first structure element and said second structure elements are formed on a surface of the mask; and
said matrix of said second structure elements surrounds said first structure elements and fills up an entire area of the surface.
7. A mask blank for producing the mask according to claim 1 , comprising:
a substrate;
a first layer having a matrix configuration of structure elements on said substrate; and
a second opaque or semitransparent layer for forming first structure elements on the mask disposed above said first layer.
8. The mask blank according to claim 7 , which comprises a filling material disposed in interspaces formed in said matrix configuration.
9. The mask blank according to claim 7 , which further comprises a third semitransparent layer disposed between said first layer and said second layer.
10. The mask blank according to claim 7 , wherein said first layer with said matrix configuration of structure elements comprises molybdenum silicide.
11. The mask blank according to claim 8 , wherein said filling material in said interspaces includes at least one material selected from the group consisting of an oxide and a nitride.
12. The mask blank according to claim 8 , wherein said filling material and a material in said first layer have similar optical properties.
13. The mask blank according to claim 12 , wherein the similar optical properties include transparency and phase shift properties.
14. A method of producing a mask, which comprises:
providing a mask blank with:
a substrate;
a first layer having a matrix configuration of structure elements on the substrate; and
a second opaque or semitransparent layer for forming first structure elements on the mask disposed above said first layer;
and producing the mask according to claim 1 from the mask blank.
15. A method of producing a mask for projecting a structure pattern onto a semiconductor substrate in an exposure unit, the exposure unit having a minimum resolution limit for projecting the structure pattern onto the semiconductor substrate, the method which comprises:
providing a mask blank according to claim 7 ; and
processing the mask blank to produce a mask having:
the substrate;
at least one raised first structure element on the substrate, the first structure element having a lateral extent amounting to at least the minimum resolution limit;
a configuration of raised second structure elements, the second structure elements:
being disposed in a vicinity of the first structure element on the substrate and arranged in a matrix with a row spacing and a column spacing;
having a substantially identical shape and size; and
having a respective lateral extent less than the minimum resolution limit, so that the structure configuration cannot be transferred to a photosensitive resist layer formed on the semiconductor substrate.