OPC Mask Pattern Segmentation for High Resolution Proximity Exposure
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Solution Overview
Problem
Current proximity exposure machines have limitations in achieving high resolution and aperture ratio for high pixel density devices, which are essential for advanced semiconductor fabrication.
Innovation Solution
A design method for mask patterns incorporating an optical proximity correction (OPC) technique, where a mask with specific clear and dark areas is used in a proximity exposure machine to form an imaged pattern with a smaller area than the OPC pattern, improving resolution and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask patterns are used in proximity exposure machines, then the aperture ratio can be maintained, but the resolution is limited and cannot achieve high pixel density
Solution Approach 1:
The mask pattern is segmented into multiple functional zones: a first clear area surrounding a first dark area, with the first clear area having a larger area than the first dark area. This segmentation allows different regions to serve different purposes in controlling light exposure, enabling resolution improvement while managing mask complexity.
Solution Approach 2:
Different areas of the mask pattern are assigned different optical properties (clear vs. dark areas with specific area ratios). The first clear area and first dark area have distinct local qualities that control light transmission differently, allowing precise local control of exposure to achieve high resolution imaging.
2Manufacturing precision
If the mask pattern area is reduced to improve resolution, then the aperture ratio deteriorates
Solution Approach 1:
The mask pattern employs a nested structure where the first dark area is surrounded by the first clear area. This nesting arrangement allows the pattern to maintain an effective imaging area while the surrounding clear area compensates for optical proximity effects, thereby improving resolution without sacrificing aperture ratio.
Solution Approach 2:
The patent converts the harmful optical proximity effects (which normally cause pattern distortion and limit resolution) into a benefit by designing the first clear area to be larger than the first dark area. This deliberate design allows the optical effects to work in favor of achieving smaller, more precise imaged patterns while maintaining adequate aperture ratio.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively reduces the average critical dimension of via hole patterns to less than 5 μm and narrows the variation range to 2 μm, while maintaining or exceeding the process window of existing technologies, thus enhancing the resolution and aperture ratio of products.
Implementation Method 1
a mask comprising an optical proximity correction (OPC) pattern comprising a first clear area and a first dark area
Implementation Method 2
exposing the substrate to light to form an imaged pattern on the substrate
Data Source
AI summary
A design method for mask patterns is provided. The design method includes providing an exposure machine with a mask including an optical proximity correction (OPC) pattern including a first clear area and a first dark area, wherein the first clear area surrounds the first dark area, placing a substrate in the exposure machine, and exposing the substrate to light to form an imaged pattern on the substrate, wherein the imaged pattern has an area smaller than that of the optical proximity correction (OPC) pattern.