This application claims the priority benefit of Taiwan application serial no. 99143375, filed on Dec. 10, 2010 and Taiwan application serial no. 100127734, filed on Aug. 4, 2011. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.
The disclosure relates to a showerhead integrating intake and exhaust.
Metal organic chemical vapor deposition (MOCVD) is one of the methods for performing an epitaxial process on a wafer. Currently, a showerhead is mostly adopted as the intake apparatus of MOCVD. However, the design of the showerhead usually causes holdup of the gas concentration in the center, such that this area can not be utilized and further affects the wavelength uniformity at the edge of the wafer. As the above phenomenon occurs in a chamber of small size, the control of uniformity becomes more difficult in the development of a large size chamber. That is, other than the gas holdup region in the center, the gas concentration closer to the extraction becomes lower as the path of the gas flow lengthens.
Therefore, patents related to improving the uniformity of the airflow field have been disclosed such as U.S. Pat. No. 7,138,336 B2 or U.S. Pat. No. 7,641,939 B2. The patents aforementioned adopt a showerhead for intake and a chamber with lateral exhaust to control the intake and exhaust of gas.
A showerhead integrating intake and exhaust is introduced herein. Other than solving the gas holdup in the showerhead, the showerhead of the disclosure can also balance a concentration distribution on a surface of a substrate and exhaust a byproduct from a reaction process.
A showerhead integrating intake and exhaust is introduced herein for showering a gas. The showerhead at least includes a showerhead body having a gas-active surface and a plurality of intake bores disposed on the gas-active surface. The showerhead body further includes a central exhaust vent disposed on a center of the gas-active surface.
In light of the foregoing, the intake and the exhaust of gas are both designed in the showerhead of the disclosure to extract the high concentration gas in the center of the chamber using a regional intake and exhaust showering technique for the concentration in the center and on the sides to be uniform. Also, the byproduct generated from the reaction can be exhausted first to prevent the byproduct from remaining in the chamber for too long so as to affect the reaction product such as generating an epitaxy of poor quality.
Several exemplary embodiments accompanied with figures are described in detail below to further describe the disclosure in details.
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments and, together with the description, serve to explain the principles of the disclosure.
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In the present embodiment, a ratio of an area of the central exhaust vent 206 to an area of the intake bores 204 ranges from 0.03 to 0.04, for instance. Also, an extraction end 206a of the central exhaust vent 206 may concave inward to the showerhead body 202 to prevent a gas being extracted from mixing with a gas being passed through the intake bores 204. In other words, when a location of the extraction end 206a of the central exhaust vent 206 is closer to the substrates 210 than the outlets of the intake bores 204 are, the performance of the central exhaust vent 206 may be affected.
In the present embodiment, at least one flow meter 212 is disposed to control exhaust amount of the central exhaust vent 206, for example. The air displacement of the central exhaust vent 206 has to be controlled to be less than the air flow passed from the intake bores 204. Moreover, the internal pressure of a reaction chamber 216 needs to be maintained consistently. In addition, the showerhead 200, for example, further includes a lift mechanism 214 to adjust a distance between the substrates 210 and the showerhead body 202. Further, processes such as coating is facilitated when an area of the showerhead body 202 is larger than a total area of the substrates 210, for example.
The showerhead 200 disposed in the reaction chamber 216 not only adopts the central exhaust vent 206 to balance the gas concentration in the center and the sides of the reaction chamber 216, but an extraction vent such as a lateral extraction vent 218 is designed in the reaction chamber 216 to perform the main extraction.
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In the present exemplary embodiment, the showerhead 300 further includes a lift mechanism 406 to adjust a distance between the substrates 400 and the showerhead body 302, for example. Furthermore, processes such as coating is facilitated providing that an area of the showerhead body 302 is larger than a total area of the substrates 400, for example. Moreover, in the reaction chamber 408, extraction devices such as lateral extraction vents 410 and the like may be installed, for instance.
In summary, the showerhead of the disclosure integrates intake and exhaust at the same time. Thus, the concentration in the center and the sides of the chamber is consistent through the showering technique of regional intake and exhaust. The byproduct generated from the reaction process can also be extracted first in the disclosure to prevent the byproduct from residing in the chamber for too long so as to affect the reaction results such as the generation of poor quality epitaxy during vacuum coating. The showerhead of the disclosure further includes properties such as simple structure, low processing cost, and easy maintenance.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
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99143375 | Dec 2010 | TW | national |
100127734 | Aug 2011 | TW | national |