Wafer Edge Rinse Positioning for Uniform Resist Removal on Warped Substrates
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Solution Overview
Problem
Warped semiconductor wafers during the manufacturing process lead to non-uniform removal of resist films at the periphery, affecting the precision and integration of circuits due to variations in gap and optical path lengths during edge rinsing and exposing processes.
Innovation Solution
A substrate processing method that calculates the warp amount of the substrate using image processing and adjusts the supply position and exposure width accordingly to ensure uniform removal of the resist film, even if the substrate is warped, by determining the optimal position for solvent supply and exposure based on the substrate's shape data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a warped wafer is processed using conventional edge rinsing or periphery exposing methods, then the processing can be completed, but the removal width of the peripheral portion becomes non-uniform due to varying gap and optical path lengths
Solution Approach 1:
The patent applies dynamics by making the nozzle position adjustable rather than fixed. The nozzle is positioned at a height that corresponds to the average radius of the wafer, and the system dynamically adapts to wafer warp by maintaining this average position, allowing uniform solvent supply despite variations in local wafer surface height
Solution Approach 2:
The patent applies local quality by recognizing that different regions of the wafer have different heights due to warp, and by positioning the nozzle to supply solvent to the peripheral portion at an optimal average height, ensuring that each local region receives appropriate processing despite the overall non-planar shape
2Ease of operation
If the nozzle height is fixed during edge rinsing process, then the process is simple to operate, but the gap between the periphery and nozzle varies causing non-uniform removal width
Solution Approach 1:
The patent applies parameter changes by optimizing the nozzle height parameter to correspond to the average radius of the wafer. This single parameter adjustment ensures that the nozzle is positioned at the appropriate height to supply solvent uniformly across the peripheral portion, balancing ease of operation with processing precision
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 method allows for proper processing of warped substrates, promoting higher integration of circuits by ensuring uniform removal widths and preventing defects, thus improving process efficiency and substrate utilization.
Implementation Method 1
performs image processing of the image taken in the first step, thereby to obtain shape data of the end face of the reference substrate
Implementation Method 2
supplies the organic solvent from the supply position to dissolve the peripheral portion of the coating film and remove the same from the substrate
Data Source
AI summary
A processing method in one embodiment includes: a step that takes an image of the end face of a reference substrate, whose warp amount is known, over the whole periphery thereof using a camera to obtain shape data of the end face of the reference substrate; a step that takes an image of the end face of a substrate over the whole periphery thereof using a camera to obtain shape data of the end face of the substrate; a step that calculates warp amount of the substrate based on the obtained shape data; a step that forms a resist film on a surface of the substrate; a step that determines the supply position from which an organic solvent is to be supplied to a peripheral portion of the resist film and dissolves the peripheral portion by the solvent supplied from the supply position to remove the same from the substrate.