Sloped Annular Flow Control for Cleaner Wafer Edge Etching
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Solution Overview
Problem
During semiconductor manufacturing processes like plasma etching, unwanted particles and contaminants can accumulate in the process chamber and potentially damage the wafer, especially at the edge or periphery, due to inadequate venting and retention mechanisms in traditional horizontally planar plasma and gas flow control systems.
Innovation Solution
A perforated and sloped annular plasma and gas flow control device is employed, which deflects unwanted particles away from the wafer surface by directing them away from the device side, utilizing a downwardly angled design that encircles the mounting platform, thereby reducing the likelihood of contamination and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a horizontally planar plasma and gas flow control system is used, then the structure is simple and easy to manufacture, but unwanted particles and contaminants accumulate in the process chamber and damage the wafer edge
Solution Approach 1:
The patent applies curvature by transitioning from a horizontally planar flow control system to a sloped annular configuration. The sloped surface angles away from the wafer surface, creating a curved geometric profile that actively deflects particles and contaminants away from the wafer edge, thereby protecting the wafer while maintaining structural simplicity
Solution Approach 2:
The invention introduces a dimensional change by adding a slope angle to the flow control device. Instead of a flat horizontal plane, the annular flow control structure is inclined at an angle relative to the wafer surface, creating a three-dimensional configuration that provides active particle deflection functionality without significantly increasing device complexity
2Reliability
If traditional horizontal flow control is used, then the device is simple to operate, but particles are not effectively vented and retained, leading to wafer damage
Solution Approach 1:
The sloped annular configuration uses a curved surface that angles away from the wafer to passively direct particle flow toward the exhaust ports. This geometric curvature automatically guides contaminants away from the wafer edge without requiring complex active control mechanisms, maintaining ease of operation while improving particle venting effectiveness
3Object-affected harmful factors
If a sloped annular flow control device is implemented, then particle deflection and wafer protection are improved, but the device structure becomes more complex
Solution Approach 1:
The sloped annular structure employs a simple curved surface geometry that can be integrated into existing chamber designs. The slope angle provides active particle deflection functionality, redirecting contaminants away from the wafer edge toward exhaust ports, thereby reducing contamination without requiring multiple components or complex mechanisms
Solution Approach 2:
The sloped annular flow control device performs multiple functions simultaneously: it serves as a gas distribution structure, a particle deflection surface, and an exhaust flow guide. This multi-functionality is achieved through a single integrated component with a sloped geometry, avoiding the need for separate particle management systems and thereby limiting the increase in device complexity
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 sloped annular plasma and gas flow control device effectively minimizes the retention of unwanted particles on the semiconductor wafer, enhancing wafer acceptance testing and chip probe metrology by deflecting contaminants away from the wafer surface, thus improving the overall manufacturing process.
Implementation Method 1
A perforated and sloped annular plasma and gas flow control device is employed, which deflects unwanted particles away from the wafer surface by directing them away from the device side
Data Source
AI summary
A method of plasma etching a semiconductor wafer includes: securing the semiconductor wafer to a mounting platform within a process chamber such that an outer edge of the semiconductor wafer is encircled by a sloped annular ring having a plurality of perforation therein, the sloped annular ring having an inner edge at a first end of the sloped annular ring and an outer edge at a second end of the sloped annular ring. Suitably, the first end is opposite the second end and the first end resides in a first plane and the second end resides in a second plane different from the first plane. The method further includes generating a plasma within the process chamber such that the semiconductor wafer is exposed to the plasma and creating a flow of at least one of plasma and gas through the perforations in the sloped annular ring.