Substrate Dose Mapping With Rotation for Residual Curvature Control
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Solution Overview
Problem
Existing methods for stress control in substrates, such as semiconductor wafers, face challenges in effectively reducing out-of-plane distortion (OPD) and in-plane distortion (IPD) during device fabrication, particularly due to complex stress patterns and non-uniform ion beam treatments.
Innovation Solution
The implementation of dose mapping and substrate rotation techniques using a scanning ion beam to selectively implant ions at different twist angles, creating a pattern that matches the residual curvature map to reduce substrate OPD and IPD, thereby improving the resolution of implantation and reducing distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a non-uniform ion beam is used to treat complex stress OPD patterns, then the ion implantation process is simpler, but the manufacturing precision of OPD control deteriorates
Solution Approach 1:
The patent segments the ion implantation process into multiple exposures at different twist angles (e.g., 0°, 45°, 90°, 135°). Each exposure targets specific regions of the substrate with controlled ion doses, allowing complex OPD patterns to be treated in discrete steps rather than requiring a single complex non-uniform beam treatment.
Solution Approach 2:
The patent introduces the twist angle dimension to the ion implantation process. By rotating the substrate between exposures and implanting at multiple angular orientations, the system transforms a two-dimensional non-uniform beam problem into a multi-dimensional solution space, achieving superior OPD control through angular diversity.
2Manufacturing precision
If multiple exposures at different twist angles are used, then the resolution of implantation is improved, but the processing time increases
Solution Approach 1:
The patent employs periodic action by repeating the ion implantation exposure at systematically different twist angles. This periodic multi-angle exposure approach achieves high-resolution OPD control while maintaining efficient processing through regular, repeating cycles of exposure and rotation.
Solution Approach 2:
The patent performs preliminary actions by measuring the OPD pattern before implantation and calculating the optimal dose map in advance. This pre-planning allows the multiple exposures to be executed efficiently with predetermined parameters, reducing actual processing time while maintaining high resolution.
3Manufacturing precision
If ion implantation is used to modify wafer stress, then the OPD control capability is enhanced, but the device complexity increases
Solution Approach 1:
The patent utilizes parameter changes by varying the twist angle parameter between exposures and adjusting the ion dose parameter based on the measured OPD pattern. These controlled parameter variations enable precise stress modification without requiring complex additional hardware, leveraging existing ion implantation system capabilities.
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 allows for more accurate control of substrate stress and distortion, enhancing the precision of subsequent processing operations like lithography by targeting high-curvature regions with precise ion doses, leading to improved overlay accuracy and reduced residual curvature.
Implementation Method 1
ion implantation of a backside of a wafer has been explored for modifying wafer stress, and thus modifying OPD
Data Source
AI summary
A method may include generating a residual curvature map for a substrate, the residual curvature map being based upon a measurement of the substrate. The method may include generating a dose map based upon the residual curvature map, the dose map being for processing the substrate using a patterning energy source. The method may include applying the dose map to process the substrate using the patterning energy source, wherein the dose map is applied by performing a plurality of exposures of the substrate to the patterning energy source, at a plurality of different twist angles.