Valve Configuration for TEOS Deposition Uniformity
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Solution Overview
Problem
Conventional substrate processing systems face challenges in achieving uniform deposition rates and reducing defects, particularly due to the mixing of helium and tetraethyl orthosilicate (TEOS) in delivery lines, which leads to micro-bubble formation and unstable film deposition.
Innovation Solution
The method involves a liquid precursor delivery system with a controller-operated valve configuration that minimizes the mixing of TEOS and helium in supply conduits, using a purge gas to prevent micro-bubble formation and reducing the need for extensive priming, thereby stabilizing film deposition rates and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If liquid precursor (TEOS) and purge gas (helium) are supplied through mixed delivery lines, then the system can operate with simpler valve configuration, but micro-bubbles form and deposition uniformity deteriorates
Solution Approach 1:
The delivery system is segmented into separate pathways: one for liquid precursor (TEOS) and another for purge gas (helium). This segmentation prevents mixing of the two substances in the delivery lines, eliminating micro-bubble formation while maintaining controlled valve operations for precise deposition uniformity.
Solution Approach 2:
The harmful mixing effect is extracted by removing the common delivery line configuration. Instead of mixing TEOS and helium in a shared conduit, the system extracts them into separate supply paths, allowing independent control and preventing the formation of unstable gas-liquid mixtures that cause deposition defects.
2Manufacturing precision
If extensive priming is performed to remove micro-bubbles, then deposition uniformity can be improved, but processing time and productivity decrease
Solution Approach 1:
The system performs preliminary action by maintaining separate delivery lines for liquid precursor and purge gas from the start, preventing micro-bubble formation before it occurs. This eliminates the need for time-consuming post-preparation priming steps, as the system is configured to avoid the problem rather than correct it later.
Solution Approach 2:
The harmful priming step is skipped entirely by redesigning the delivery system architecture. Instead of performing extensive priming to remove micro-bubbles, the system rushes through the setup phase with a pre-configured separate delivery system that prevents micro-bubble formation, directly transitioning to productive deposition operation.
3Measurement precision
If liquid precursor metering is increased for precision, then deposition control improves, but the system becomes more sensitive to micro-bubble contamination
Solution Approach 1:
The contamination source is extracted by separating the liquid precursor delivery path from the purge gas path. This extraction eliminates micro-bubble contamination in the TEOS supply, allowing precise metering of the liquid precursor without sensitivity to gas mixing, thereby maintaining both precision and reliability.
Solution Approach 2:
The system creates an inert environment for liquid precursor delivery by using separate, dedicated tubing and valve configurations that prevent contamination. This inert delivery environment protects the precisely metered TEOS from micro-bubble formation, ensuring stable and reliable deposition control.
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 approach significantly reduces defects and improves deposition rate uniformity by eliminating micro-bubble-induced instability, achieving a substantial reduction in thickness range and defect performance.
Implementation Method 1
a liquid precursor may be vaporized into a carrier gas
Implementation Method 2
perform plasma-enhanced chemical vapor deposition (PECVD)
Data Source
AI summary
Systems and methods for delivering liquid precursor in a substrate processing system include supplying liquid precursor using a first valve in fluid communication with a liquid precursor source; supplying purge gas using a second valve in fluid communication with a purge gas source; arranging a third valve having a first input port in fluid communication with an output port of the first valve and a second input port in fluid communication with an output port of the second valve; arranging an input port of a first divert injector valve in fluid communication with an output port of the third valve; and operating the first valve, the second valve, the third valve and the first divert injector valve in first, second, third and fourth modes.