US 7,001,693 B2 · Binary OPC for assist feature layout optimization

Abstract

A method of forming a photolithographic mask layout with Sub-Resolution Assist Feature (SRAF) elements on a mask for correcting for proximity effects for a pattern imaged comprising the steps of developing a layout of mask features for printing main pattern features. Provide a table of SRAF element data including spacing of main pattern features and SRAF elements, applying SRAF elements to the mask layout as a function of spacing of main pattern features and SRAF elements, legalizing the SRAF elements as a function of style options, and providing a target pattern comprising a modified layout for the mask, identifying problem edge segments of an SRAF element of the target pattern at risk of causing a printing defect, applying a selected bias to the problem edge segments to modify the pattern where there are areas of SRAF element loss, and providing an output of a modified pattern with modified SRAF elements removing the areas of SRAF element loss. The system can provide SRAF elements to the mask layout as a function of spacing of main pattern features and SRAF elements may be based on data from the SRAF table; or the system can applying model based OPC for exposure dose values based on data from the SRAF table.

Claims13

Dependent claims

A method for forming a photolithographic mask layout with Sub-Resolution Assist Feature (SRAF) elements on a mask to improve a pattern image comprising the steps of:

(a) developing a circuit layout comprising a plurality of features of a pattern,
(b) providing a table of SRAF rules relating the size and placement of said SRAF elements as a function of spacing of said features of said pattern,
(c) applying said SRAF elements to said features according to said SRAF rules,
(d) legalizing said SRAF elements,
(e) identifying problem edge segments of said features of said pattern based on insufficient SRAF element coverage,
(f) applying a selected bias to said problem edge segments to modify said features of said pattern of features locally in areas of SRAF loss, and
(g) providing an output of an enhanced mask layout with a locally modified pattern of features.

4 more elements

A model-based method of forming a photolithographic mask layout with Sub-Resolution Assist Feature (SRAF) elements on a mask to improve an imaged pattern of features comprising the steps of:

(a) providing a circuit layout comprising a main pattern of features and an initial target image pattern for a desired wafer image corresponding to said circuit layout,
(b) providing a table of SRAF rules relating the size and placement of SRAF elements as a function of spacing of said main pattern of features,
(c) applying SRAF elements to the main pattern of features for said mask according to said SRAF rules,
(d) legalizing said SRAF elements,
(e) identifying problem edge segments of the main pattern features based on insufficient SRAF element coverage,
(f) applying a selected bias to target problem edge segments of said initial target image pattern corresponding to said problem edge segments to form a modified target image pattern,
(g) applying model-based OPC to said circuit layout including said SRAF elements, until a modified circuit layout is found wherein a mask pattern using said modified circuit layout results in a simulated wafer image that substantially conforms to said modified target image pattern within a specified tolerance, and
(h) providing an output mask layout corresponding to said modified circuit layout.

5 more elements

Dependencies are inferred from the claim text.

Binary OPC for assist feature layout optimization

Life of this patent

Binary OPC for assist feature layout optimization

Life of this patent

Abstract

Claims13