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Gas Curtain Dome Isolation for CVD/EPI Chamber.

IP.com Disclosure Number: IPCOM000249805D
Publication Date: 2017-Apr-06
Document File: 5 page(s) / 180K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to improve the dome coating issue in a Chemical Vapor Deposition/Epitaxy (CVD/EPI) instrument. The method uses a single chamber and a gas curtain to isolate the dome from the deposition wafer. The approach is to change the chemistry near the dome region (compared to the wafer region), without changing the chemistry close to the wafer, thus preventing the dome coating issue commonly seen in CVD/EPI reactors.

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Title ‘Gas Curtain’ Dome Isolation for CVD/EPI Chamber Abstract Disclosed is a method to improve the dome coating issue in a Chemical Vapor Deposition/Epitaxy (CVD/EPI) instrument. The method uses a single chamber and a gas curtain to isolate the dome from the deposition wafer. The approach is to change the chemistry near the dome region (compared to the wafer region), without changing the chemistry close to the wafer, thus preventing the dome coating issue commonly seen in CVD/EPI reactors. Problem Chemical Vapor Deposition/Epitaxy (CVD/EPI) is a widely-used method in the semiconductor line. Reducing lot-to-lot/wafer-to-wafer variation is the goal for every process step. One problem with the Low-Pressure Chemical Vapor Deposition/Epitaxy (LPCVD/EPI) process is that the chamber can become unstable over time. Dome coating causes temperature drift on the wafer, while temperature is one of the most critical factors for CVD/EPI growth rate. Figure 1: EPI/CD drifting from time-to-time

Figure 2: Dome coating observed on dome

One method for addressing the dome coating issue is process adjustment. Dome coating affects the wafer temperature; the method requires the consistent adjustment of the process temperature set point to compensate for the shift from dome coating. Another existing method is to clean the chamber to remove the dome coating. Neither of these options prevents dome coating formation. Designs to reduce/prevent chamber coating include reducing dome temperature by blowing air to cool the dome (from outside of the chamber). The lower temperature can reduce the growth rate on the dome. Even with this method, the dome temperature can easily go up to >500C̊ when the wafer temperature is 700C. Figure 3: Current design

A method is needed to improve this dome coating issue in a CVD/EPI instrument. Solution/Novel Contribution The novel contribution a method to use a single chamber and a gas curtain to isolate the dome from the deposition wafer. The approach is to change the chemistry near the dome region (compared to the wafer region), without changing the chemistry close to wafer, thus preventing the dome coating issue commonly seen in CVD/EPI reactors. M...