Gas Flow Blocking Part for ESC Polymer Management
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Solution Overview
Problem
In semiconductor etching processes, polymers generated during the etching of semiconductor wafers often remain on the electrostatic chuck (ESC), leading to helium leaks and process failures due to inadequate gas flow blocking, causing temperature instability and plasma impedance changes.
Innovation Solution
A semiconductor etching apparatus with a gas flow blocking part, such as an O-ring, positioned between the ESC and quartz rings to prevent polymer adsorption and helium leaks by blocking the vacuum path and ensuring continuous helium flow under the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a vacuum path is formed between the ESC and parts for polymer discharge, then polymer removal is improved, but helium leaks increase due to inadequate gas flow blocking
Solution Approach 1:
The vacuum path is segmented into multiple regions by positioning the gas flow blocking part (O-ring) between the ESC and the quartz ring. This creates a first vacuum path region for polymer discharge and a second vacuum path region for helium flow, allowing polymer removal while preventing helium leaks through proper spatial separation and blocking.
Solution Approach 2:
The gas flow blocking part (O-ring) acts as an intermediary element between the ESC and the quartz ring. It selectively blocks gas flow in specific regions while allowing vacuum paths to function, thereby preventing helium from entering the polymer discharge region while maintaining the vacuum path for polymer removal.
2Temperature
If the ESC surface is exposed to vacuum path for cooling, then temperature control is improved, but polymer adsorption increases leading to chucking force decrease
Solution Approach 1:
The vacuum path is divided into separate regions: a first vacuum path region that allows polymer discharge away from the ESC, and a second vacuum path region that maintains helium flow for cooling. The gas flow blocking part creates this segmentation, ensuring polymers are removed before they can adsorb onto the ESC surface while cooling continues uninterrupted.
Solution Approach 2:
The harmful polymers are extracted from the system through the dedicated first vacuum path region before they can reach and adsorb onto the ESC surface. The gas flow blocking part directs polymers away from the ESC, separating the polymer removal function from the cooling function.
3Temperature
If continuous helium flow is maintained under the wafer for cooling, then temperature stability is improved, but polymer contamination of helium increases
Solution Approach 1:
The vacuum path is segmented into a first region for polymer discharge and a second region for helium flow, separated by the gas flow blocking part. This ensures that polymers are removed through the first region before they can contaminate the helium in the second region, maintaining both temperature stability and plasma impedance stability.
Solution Approach 2:
The gas flow blocking part serves as an intermediary barrier that prevents polymer-laden vacuum flow from mixing with the continuous helium flow under the wafer. It allows the helium cooling flow to continue uninterrupted while blocking polymers from entering the helium stream, thus preventing plasma impedance changes.
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
Prevents polymer accumulation on the ESC during wafer transfer, reducing helium leaks and maintaining stable plasma conditions, thereby enhancing process reliability and reducing maintenance needs.
Implementation Method 1
high power is applied to the ESC so that a coulomb force is generated and the wafer is chucked
Implementation Method 2
ionizing the gas, and accelerating the ionized gas on the surface of a wafer, so as to physically and chemically remove the uppermost layer of the surface of the wafer
Implementation Method 3
A reactive ion etching process is performed by supplying an etching gas into a reaction chamber, ionizing the gas, and accelerating the ionized gas
Data Source
AI summary
There is provided a semiconductor etching apparatus which removes particles remaining on the upper surface of an electro static chuck (ESC) during an etching process, thereby preventing a chucking force from decreasing and minimizing a leak of helium. To prevent a failure of the etching process due to a wafer chucking failure, by preventing polymers from falling down on the upper part of the ESC when a wafer is dechucked or transferred, the semiconductor etching apparatus comprises: an ESC selectively holding a wafer to be entered and positioned inside a chamber, and including a lower electrode part to which RF power is applied; parts positioned at a stepped portion of the ESC and respectively surrounding a side of the ESC; and a gas flow blocking part blocking a gas flow in a vacuum path formed between the ESC and the parts.