Preheating Ring Cleaning via Cross-Flow Etching Gas
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Solution Overview
Problem
The existing methods for producing semiconductor wafers with epitaxial layers face productivity losses due to the time-consuming chamber etching process, particularly because of inadvertent material deposition on the preheat ring, which requires interrupting the coating process and prolongs the etching duration.
Innovation Solution
The method involves using additional second gas inlet openings to direct etching gas across the preheat ring in directions perpendicular to the primary gas flow, allowing for more effective removal of material deposits during chamber etching, thereby reducing the overall etching time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chamber etching is performed to remove material deposits from the preheating ring, then the reactor chamber is cleaned, but productivity is reduced due to process interruption
Solution Approach 1:
The patent introduces etching gas through second gas inlet openings positioned to directly target the preheating ring before material deposits become problematic. This preliminary action prevents excessive deposit accumulation, reducing the frequency and duration of full chamber etching cycles needed to maintain cleanliness.
Solution Approach 2:
The gas inlet system is segmented into first gas inlet openings for general process gas distribution and second gas inlet openings specifically positioned for etching gas delivery to the preheating ring. This segmentation allows targeted cleaning without requiring complete chamber shutdown or full chamber etching, thus maintaining productivity while ensuring cleaning effectiveness.
2Device complexity
If etching gas is introduced through first gas inlet openings only, then the process is simple, but material deposits on the preheating ring are not effectively removed
Solution Approach 1:
The patent adds a spatial dimension to the gas inlet system by introducing second gas inlet openings positioned at different locations and angles relative to the preheating ring. This dimensional addition creates direct gas flow paths to the preheating ring surface, dramatically improving deposit removal effectiveness without significantly increasing overall system complexity.
3Reliability
If the coating process is interrupted for chamber etching, then material deposits are removed, but the overall production time increases
Solution Approach 1:
By introducing etching gas through second gas inlet openings during or between coating cycles, the patent performs preliminary cleaning action that prevents excessive deposit buildup. This reduces the frequency and duration of full chamber etching interruptions, minimizing time loss while maintaining reactor chamber cleanliness.
Solution Approach 2:
The dual gas inlet system enables continuous or near-continuous cleaning action through the second openings while coating proceeds through the first openings. This continuity reduces the need for complete process interruptions, maintaining both cleanliness and production throughput.
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 shortens the time required to remove material deposits from the preheat ring by up to 40% compared to traditional methods, enhancing productivity by allowing continuous wafer coating operations.
Implementation Method 1
A process gas is introduced into the reactor chamber and passed over the substrate wafer via a gas injector through gas inlet ports. The process gas decomposes and partially deposits as a layer of material on the surface of the substrate wafer exposed to the process gas.
Implementation Method 2
This is typically done by a process called chamber etching, in which an etching gas, which reacts with the material deposits to form gaseous reaction products, is introduced into the reactor chamber through the gas inlet openings instead of the process gas.
Implementation Method 3
During layer deposition, the substrate wafer rests on a susceptor and is heated by radiation from upper and lower lamp banks located above and below the upper and lower domes.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method and to a device for producing coated semiconductor wafers, comprising the introduction of a process gas through first gas inlet openings along a first flow direction into a reactor chamber and over a substrate wafer of semiconductor material in order to deposit a layer on the substrate wafer, which lies on a susceptor, wherein material originating from the process gas is precipitated on a pre-heating ring, which is arranged around the susceptor, and comprising the removal of the coated substrate wafer from the reactor chamber, characterized by the following, after the removal of the coated substrate wafer from the reactor chamber: the removal of the material precipitate from the pre-heating ring by the introduction of an etching gas through the first gas inlet openings into the reactor chamber in the first flow direction and through second gas inlet openings, between which the first gas inlet openings are arranged, over the pre-heating ring in further flow directions that cross the first flow direction.