Photolithographic mask
View Patent ↗A photolithographic mask has the advantage that a combination of dummy structures, whose pattern is imaged into the resist layer, and auxiliary structures, whose pattern is not imaged into the resist layer, makes it possible to achieve a significant improvement in the imaging properties of the main structures which are disposed at an edge of a region containing a multiplicity of main structures. In particular, constrictions at the structures can be significantly reduced or completely avoided and/or a so-called “tilting” of the structures under non-optimum focus conditions is significantly reduced or completely avoided.
1. A photolithographic mask for use in irradiating radiation-sensitive resist layers on semiconductor substrates for fabricating integrated semiconductor products, the photolithographic mask comprising:
at least one radiation-transmissive substrate; and
at least one layer disposed on said radiation-transmissive substrate and selected from the group consisting of radiation-opaque layers and half-tone layers, said layer having:
at least one region with a multiplicity of main structures, said main structures formed such that a pattern formed by said main structures is transferred to a resist layer in an event of irradiation and first structures produced by said main structures fulfill a predetermined purpose on a semiconductor substrate of a completed semiconductor product;
dummy structures disposed at least at an edge of said region, said dummy structures formed such that a pattern formed by said dummy structures is transferred to said resist layer in the event of the irradiation and second structures produced by said dummy structures do not fulfill a predetermined purpose on the semiconductor substrate of the completed semiconductor product; and
at least one auxiliary structure disposed at least at said edge of said region, said auxiliary structure formed such that a pattern formed by said auxiliary structure cannot be transferred to the resist layer in the event of the irradiation.
2. The photolithographic mask according to claim 1 , wherein said main structures are oriented substantially parallel to each other in a given direction.
3. The photolithographic mask according to claim 2 , wherein said dummy structures are oriented substantially parallel to each other.
4. The photolithographic mask according to claim 3 , wherein said dummy structures are oriented in said given direction.
5. The photolithographic mask according to claim 4 , wherein said auxiliary structure is one of a multiplicity of auxiliary structures all oriented substantially parallel to each other.
6. The photolithographic mask according to claim 5 , wherein said auxiliary structures are oriented in said given direction.