Semiconductor Structure Double-Exposure Pattern Fidelity
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Solution Overview
Problem
In semiconductor manufacturing, the miniaturization of devices leads to optical proximity effect (OPE) issues such as right-angled corner rounding, line end shortening, and line width variations due to diffraction when transferring patterns through masks with fine feature sizes, which are not adequately addressed by existing double-exposure techniques.
Innovation Solution
A semiconductor structure and manufacturing method involving a substrate with a trench region and two material layers, where the second material layer is disposed between the first regions, allowing for a nearly rectangular pattern formation through a double-exposure technique that alleviates OPE-related defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the interval between transparent regions in a mask is scaled down to obtain fine-sized devices, then device size is reduced, but diffraction occurs and resolution is reduced
Solution Approach 1:
The patent divides the pattern transfer process into two separate exposure steps. The first exposure forms initial patterns with larger intervals that avoid diffraction, and the second exposure adds remaining patterns. This segmentation of the exposure process allows fine features to be created without suffering from diffraction-related resolution loss that would occur if all features were exposed in a single step with scaled-down intervals.
Solution Approach 2:
The first exposure process performs preliminary pattern formation before the second exposure. By pre-forming certain patterns with larger spacing in the first exposure, the method prepares the photoresist layer in advance, allowing subsequent patterns to be added without the diffraction problems that would arise from attempting to expose all fine features simultaneously.
2Length of moving object
If the interval between transparent regions in a mask is scaled down to obtain fine-sized devices, then device size is reduced, but pattern deformation occurs
Solution Approach 1:
The pattern transfer is segmented into two exposure processes, each handling different portions of the final pattern. This segmentation prevents pattern deformation by ensuring that no single exposure step requires excessively small intervals between transparent regions, thereby avoiding the optical proximity effects that cause corner rounding, line end shortening, and line width variations.
Solution Approach 2:
The first exposure performs preliminary pattern formation with larger intervals that do not suffer from optical proximity effects. This preliminary action establishes a foundation pattern that is free from deformation, and the second exposure then adds remaining features without introducing the same deformation problems.
3Manufacturing precision
If double-exposure technique is used to form target pattern, then pattern fidelity is improved, but process complexity increases
Solution Approach 1:
The complex pattern formation task is segmented into two manageable exposure steps with distinct functions. The first exposure creates initial patterns with specific spacing requirements, and the second exposure adds remaining patterns. This segmentation makes the overall complex process more controllable and easier to optimize compared to attempting single-step exposure of all fine features.
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 enables the formation of semiconductor structures with nearly rectangular patterns, free from right-angled corner rounding, by using a double-exposure technique with specific layer configurations and etching processes, improving pattern fidelity and accuracy.
Implementation Method 1
When the light passes through the mask, diffraction occurs and reduces resolution
Implementation Method 2
The photo-mask pattern is then proportionally transferred to a photoresist layer positioned on the semiconductor wafer
Data Source
AI summary
A semiconductor structure is provided in the present invention. The semiconductor structure includes a substrate, a first material layer and a second material layer. A trench region is defined on the substrate. The trench region includes two separated first regions and a second region, wherein the second region is adjacent to and between the two first regions. The first material layer is disposed on the substrate outside the trench region. The second material layer is disposed in the second region and is level with the first material layer.