Optical Proximity Correction Using Smooth Layout Segmentation
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Solution Overview
Problem
Current optical proximity correction techniques fail to guarantee sufficient process windows for semiconductor chip patterns with increasing integration densities, leading to unwanted distortions and defects due to varying light intensity between dense and isolation regions during the optical lithography process.
Innovation Solution
A method that modifies the retarget layout by dissecting it into segments and applying a smooth process, which involves adjusting the widths of adding patterns and extending or shrinking certain features, followed by an optical proximity correction process to generate a smooth layout that improves pattern fidelity and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical proximity correction is applied to original patterns with increasing integration density, then pattern fidelity is improved, but light intensity variation between dense and isolation regions causes defects
Solution Approach 1:
The retarget layout is divided into multiple segments along the horizontal direction. This segmentation allows different regions (dense and isolation) to be processed independently, enabling targeted OPC corrections that account for local light intensity variations while maintaining overall pattern fidelity.
Solution Approach 2:
Different OPC correction parameters are applied to different segments based on their specific characteristics. Dense regions receive different corrections compared to isolation regions, allowing each area to be optimized for its local lighting conditions and preventing uniform corrections from causing defects in specific areas.
2Reliability
If retarget process is applied to improve process window during etching, then etching process window is improved, but light intensity varies greatly between dense region and isolation region
Solution Approach 1:
The layout is segmented into multiple regions, allowing the retarget process to be applied selectively to each segment with appropriate parameters. This enables optimization of the etching process window for each region while controlling light intensity variations through targeted corrections.
Solution Approach 2:
The OPC process modifies geometric parameters (line widths, spacing, shape) of pattern elements in different segments to compensate for local light intensity variations. By changing these parameters selectively, the process achieves uniform exposure across the wafer while maintaining an improved etching process window.
3Manufacturing precision
If pre-OPC process is applied to improve process window for specific features, then printability is improved, but new shapes such as assist features are generated that require additional processing
Solution Approach 1:
The retarget process is performed before the final OPC process to pre-optimize the pattern for etching. This preliminary action prepares the pattern by creating appropriate feature sizes and configurations that will respond better to subsequent OPC corrections, improving printability while controlling the generation of complex assist features.
Data Source
AI summary
A smooth process is provided in the present invention. The smooth process is applied to a retarget layout, wherein the retarget layout is dissected into a plurality of segments. Furthermore, the retarget layout comprises a first original pattern, a first adding pattern and a second adding pattern. The smooth process includes changing the second adding pattern to a first smooth pattern. Latter, a second smooth pattern is added to extend from a bottom of the first smooth pattern and a tail portion of the first adding pattern is shrunk to a third smooth pattern. After the smooth process, an optical proximity correction process is applied to the smooth layout to produce an optical proximity correction layout.