Silicon Wafer Edge Shape Evaluation for Film and Sensor Reliability
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Solution Overview
Problem
Conventional methods fail to accurately measure and control the shape of the boundary region between the main surface and chamfered portion of silicon wafers, leading to issues such as photoresist film bursting, oxide film delamination, and poor detection by positioning sensors during device processes.
Innovation Solution
A method and apparatus for evaluating the edge shape of silicon wafers using new definitions to determine the shape of the boundary region, allowing for precise control of parameters like curvature (Rx) and angle (θx), ensuring the silicon wafer has a suitable shape to prevent these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used to evaluate chamfered portion dimensions, then standard parameters (A1, A2, BC, θ1, θ2) can be measured, but the shape of the boundary region between main surface and chamfered portion cannot be determined in detail
Solution Approach 1:
The invention divides the wafer edge into distinct regions: the main surface, the boundary region, and the chamfered portion. By introducing specific measurement points (Px1 on main surface, Px2 and Px3 on chamfered portion surface) and defining the boundary region between them, the invention segments the continuous edge structure into analyzable zones, enabling detailed shape determination of the boundary region that was previously indistinguishable using conventional measurement methods.
2Ease of manufacture
If the boundary region shape is not controlled, then manufacturing process is simpler, but photoresist film bursting and oxide film delamination occur during device processes
Solution Approach 1:
The invention performs preliminary control of the boundary region shape during wafer manufacturing by defining specific geometric parameters (curvature radius Rx ≥ 240μm, angle θx ≤ 27°) before the device fabrication process. This preliminary action ensures that the boundary region has the appropriate shape to prevent photoresist film bursting and oxide film delamination during subsequent device processes, thereby improving reliability without significantly complicating manufacturing.
3Ease of manufacture
If conventional chamfering processes are used, then chamfered portion can be formed, but the shape parameters of the boundary region cannot be controlled
Solution Approach 1:
The invention introduces a feedback mechanism where the shape of the boundary region (characterized by curvature radius Rx and angle θx) is measured and evaluated after chamfering. This measurement information is then used to adjust and optimize the chamfering process parameters, enabling precise control of the boundary region shape. The feedback loop connects the manufacturing process with quality control, allowing continuous improvement of boundary region geometry.
Data Source
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AI summary
The present invention provides a method for evaluating an edge shape of a silicon wafer, in which as shape parameters in a wafer cross section, when defining a radial direction reference L1, a radial direction reference L2, an intersection point P1, a height reference plane L3, h1[µm], h2[µm], a point Px3, a straight line Lx, an angle θx, a point Px0, δ[µm], a point Px1, and a radius Rx[µm], the edge shape of the silicon wafer is measured, values of the shape parameters h1, h2, and δ are set, the shape parameters Rx and θx are calculated in accordance with the definition based on measurement data of the edge shape, and the edge shape of the silicon wafer is determined from the calculated Rx and θx to be evaluated. Consequently, a method for evaluating an edge shape of a silicon wafer capable of preventing an occurrence of trouble such as bursting of a formed film in a film formation process using photoresist material, for example is provided.