Radial Spray Assembly for Uniform Wafer Wet Etching
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving uniformity in the thickness of the liquid film on a rotating wafer surface during monolithic wet etching, leading to inconsistent etching rates and potential bumps due to differences in edge and center linear velocities, which affects product yield.
Innovation Solution
A spray device with a spray assembly that adjusts the concentration, temperature, and flow rate of cleaning liquids across different positions on the wafer surface using multiple liquid inlet pipelines and a controlled valve system to ensure consistent cleaning rates, compensating for linear velocity differences and preventing film thickness irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cleaning liquid is sprayed evenly and vertically on the wafer surface, then the spray distribution is uniform, but the liquid film thickness becomes non-uniform in the radial direction due to different linear velocities at edge and center
Solution Approach 1:
The spray system is divided into multiple independent spray heads positioned at different radial locations on the wafer. Each spray head can independently adjust its spray parameters (flow rate, pressure, concentration, temperature) to compensate for the different linear velocities at various radial positions, thereby achieving uniform liquid film thickness across the entire wafer surface despite the rotational speed variation.
Solution Approach 2:
The single spray system is segmented into multiple spray heads distributed across different radial zones of the wafer. This segmentation allows each zone to be controlled independently, with each spray head addressing the specific liquid film thickness requirements of its local region, thus resolving the uniformity issue caused by radial velocity differences.
2Productivity
If the wafer size increases, then the processing capacity increases, but precisely controlling the rate and uniformity of monolithic wet etching becomes more challenging
Solution Approach 1:
The etching process is segmented into multiple independent spray zones, each with its own spray head and control system. This allows each zone to be optimized and controlled independently, maintaining precise etching rate uniformity even as the overall wafer size increases and more zones are added to enhance processing capacity.
Solution Approach 2:
The system dynamically adjusts etching parameters (such as corrosion solution concentration, temperature, and flow rate) for each radial position to compensate for variations in linear velocity. This enables precise control of etching rate uniformity across large wafers by changing parameters locally rather than using a single uniform setting for the entire wafer surface.
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 solution ensures uniform etching rates and prevents bumps by adjusting liquid properties radially, thereby improving product yield and precision in the etching process.
Implementation Method 1
The spray assembly is configured to spray cleaning liquid towards a to-be-cleaned surface of a to-be-processed workpiece
Implementation Method 2
A monolithic wet etching technology becomes a very important technology to improve uniformity of a film thickness
Data Source
AI summary
A spray device includes a spray assembly. The spray assembly is configured to spray cleaning liquid towards a to-be-cleaned surface of a to-be-processed workpiece. The spray assembly includes a spray head and multiple liquid inlet pipelines. The spray assembly is configured to spray cleaning liquids with different concentrations, temperatures, and/or flow rates corresponding to different positions in a radial direction of the to-be-cleaned surface to cause a cleaning rate of the cleaning liquids at the different positions in the radial direction of the to-be-cleaned surface to be consistent.