Mask Decomposition for Lithography Pattern Accuracy
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Solution Overview
Problem
As semiconductor device geometries shrink, optical lithography struggles to accurately expose regions of varying densities due to narrow process windows and interference effects, leading to pattern distortion and device failure.
Innovation Solution
A method involving the decomposition of target lithographic patterns into multiple masks using an alternating phase shift mask (altPSM) algorithm, optimizing exposure settings for each density region to prevent overexposure or underexposure, and employing multiple exposure techniques to ensure accurate pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical lithography is used to reproduce patterns onto the semiconductor substrate, then the pattern transfer process can be completed, but interference and processing effects cause distortion and deviation in the mask's patterns, especially as dimensions approach the wavelengths of light used
Solution Approach 1:
The patent segments the mask pattern into multiple regions based on feature density, applying different exposure settings to each region. This segmentation allows the system to address interference and processing effects locally rather than using a single global exposure setting, thereby improving pattern reproduction accuracy in the presence of harmful optical effects.
Solution Approach 2:
The patent implements local quality by assigning different exposure parameters (focus and dose) to different regions of the mask based on their local feature density characteristics. This local optimization enables each region to be exposed under conditions appropriate for its specific geometry, reducing distortion and deviation caused by interference effects.
2Reliability
If exposure settings are optimized for one particular region with a particular feature density, then that region can be adequately exposed, but other regions with different feature density will be overexposed or underexposed
Solution Approach 1:
The patent divides the mask into multiple segments or regions, each with its own optimized exposure settings. This segmentation allows each region to be exposed with parameters tailored to its specific feature density, ensuring adequate exposure for critical dimension regions while preventing overexposure or underexposure in other areas.
Solution Approach 2:
The patent applies local quality by assigning different exposure parameters to different regions based on their local characteristics. Each region receives exposure settings optimized for its specific feature density, enabling the system to maintain high reliability across varying geometries rather than using a single universal exposure setting.
3Length of moving object
If device geometries are shrunk to achieve smaller transistors, then device density and performance are improved, but the dimensions approach the wavelengths of light used in optical lithography, making accurate exposure impossible with single mask exposure
Solution Approach 1:
The patent segments the exposure process into multiple regional exposures, each optimized for the specific dimensional characteristics of that region. This allows accurate exposure of sub-wavelength features by treating each local area independently rather than attempting single-exposure fabrication of miniaturized geometries.
Solution Approach 2:
The patent implements local quality by applying different exposure parameters to different regions based on their local feature density and dimensional characteristics. This local optimization enables accurate exposure of small geometry transistors that would otherwise be impossible to fabricate with uniform exposure settings.
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
This approach enhances pattern integrity by allowing optimal exposure of critical dimension regions with varying densities, reducing errors and device failures, and enabling the fabrication of small geometry transistors with improved yield and reduced costs.
Implementation Method 1
decomposition of target lithographic patterns into multiple masks using an alternating phase shift mask (altPSM) algorithm
Implementation Method 2
optical lithography to reproduce the patterns onto the surface of the semiconductor substrate
Implementation Method 3
Interference and processing effects can cause distortion and deviation in the mask's patterns as they are reproduced onto the semiconductor substrate
Data Source
AI summary
A method for generating a mask pattern is provided. A target lithographic pattern comprising a plurality of first geometric regions is provided, wherein the regions between the plurality of first geometric regions comprise first spaces. The target lithographic pattern is transformed, and the transformed pattern is decomposed into a first pattern and a second pattern.