Self-Calibrating Optical Emission Spectroscopy for Plasma Monitoring
원문보기
IPC분류정보
국가/구분
United States(US) Patent
공개
국제특허분류(IPC7판)
H01L-021/306
H01L-021/02
C23F-001/00
C23C-016/00
출원번호
US-0536976
(2006-09-29)
공개번호
US-0078504
(2008-04-03)
발명자
/ 주소
Vukovic,Mirko
출원인 / 주소
TOKYO ELECTRON LIMITED
대리인 / 주소
WOOD, HERRON & EVANS, LLP (TOKYO ELECTRON)
인용정보
피인용 횟수 :
0인용 특허 :
0
초록▼
A plasma processing system and plasma monitor therefor is provided in which a plasma monitor housing is coupled to a plasma processing chamber such that a line-of-sight monitoring path extends through the housing to an optical sensor outside of a window. A separate reference signal path extends thro
A plasma processing system and plasma monitor therefor is provided in which a plasma monitor housing is coupled to a plasma processing chamber such that a line-of-sight monitoring path extends through the housing to an optical sensor outside of a window. A separate reference signal path extends through the housing from a reference light source on one side of the housing to a reference optical sensor on the other side of the housing. The housing is configured so that deposits from the chamber affect all of the windows equally, and to retard the flow of contaminating film forming material onto the windows, using, for example, baffles, gas counterflow, and a balanced radial-leg housing. A processor uses the reference signal to determine window contamination and compensate for signal attenuation along the monitoring path caused by window coating, in the making of a measurement of plasma emissions. The measurement can be used by the processing system to control the plasma.
대표청구항▼
What is claimed is: 1. A plasma monitor for a vacuum processing system, the monitor comprising: a vacuum tight housing connectable to a plasma processing chamber and having at least two line-of-sight signal paths therethrough, including a monitoring signal path and a reference signal path; at least
What is claimed is: 1. A plasma monitor for a vacuum processing system, the monitor comprising: a vacuum tight housing connectable to a plasma processing chamber and having at least two line-of-sight signal paths therethrough, including a monitoring signal path and a reference signal path; at least two windows in the housing, including a first window located in the monitoring signal path and second window located in the reference signal path; a reference signal source; at least two optical sensors including a first sensor located outside of the window in the monitoring signal path and one located outside of the window in the reference signal path and oriented to receive and measure signals in the respective paths; the monitoring signal path extending from a plasma volume in the processing chamber when the housing is coupled thereto, through the housing and the first window, to the first sensor, and the reference signal path extending from the reference signal source, through the housing, and the second window, to the second sensor; means within the housing for affecting the flow of material from the plasma volume and through the housing so as to deposit substantially equally on the first and second windows; and a processor responsive to outputs from the first and second sensors and programmed to derive a measurement of emissions from the plasma volume by adjusting output from the first sensor in accordance with output of the second sensor. 2. The plasma monitor of claim 1 wherein: the means for affecting the flow of material includes a plurality of baffles along each path to substantially equally affect the flow of film forming material to the respective first and second windows. 3. The plasma monitor of claim 1 wherein: the means for affecting the flow of material includes a central cavity centered on a point of intersection of the first and second paths, the housing being configured in a plurality of effectively similar radially extending legs, including a first leg extending from the central cavity to the first window and surrounding a portion of the first path and a second leg extending from the central cavity to the second window and surrounding a portion of the second path. 4. The plasma monitor of claim 1 wherein: the means for affecting the flow of material includes a counterflow system for affecting a flow of gas from a portion of the housing containing the windows toward the processing chamber. 5. The plasma monitor of claim 1 wherein the means for affecting the flow of material includes: a plurality of legs, including a first leg extending radially from a portion of the housing to the first window and surrounding a portion of the first path, and a second leg extending radially from the central portion of the housing to the second window and surrounding a portion of the second path; and a counterflow system including means for affecting a flow of gas from a portion of the housing containing the first and second legs to a central portion of the housing, and then from a central portion of the housing toward the processing chamber. 6. The plasma monitor of claim 1 wherein the means for affecting the flow of material includes: a first leg extending radially from a portion of the housing to the first window and surrounding a portion of the first path, and a second leg extending radially from the central portion of the housing to the second window and surrounding a portion of the second path; a purge gas supply connected to the housing near the first and second legs; an exhaust volume in the housing between the central portion thereof and the processing chamber, the exhaust volume having an exhaust pump connected thereto; and a counterflow tube extending from the central portion of the housing to the exhaust system, the tube being concentric with and surrounding a portion of the first path between the central portion and the exhaust volume. 7. A vacuum processing apparatus comprising the plasma monitor of claim 1. 8. A plasma monitor for a vacuum processing system, the monitor comprising: a vacuum tight housing connectable to a plasma processing chamber and having at least two line-of-sight signal paths therethrough, including a monitoring signal path and a reference signal path; at least two windows in the housing, including a first window located in the monitoring signal path and a second window located in the reference signal path; a reference signal source; at least two optical sensors including a first sensor located outside of the window in the monitoring signal path and one located outside of the window in the reference signal path and oriented to receive and measure signals in the respective paths; the monitoring signal path extending from a plasma volume in the processing chamber when the housing is coupled thereto, through the housing and the first window, to the first sensor, and the reference signal path extending from the reference signal source, through the housing and the second window, to the second sensor; a processor responsive to outputs from the first and second sensors and programmed to derive a measurement of emissions from the plasma volume by adjusting output from the first sensor in accordance with output of the second sensor; a plurality of baffles along each path to substantially equally affect the flow of film forming material to the respective first and second windows; a central cavity centered on a point of intersection of the first and second paths; the housing being configured in a plurality of radially extending legs, including a first leg extending from the central cavity to the first window and surrounding a portion of the first path and a second leg extending from the central cavity to the second window and surrounding a portion of the second path; a purge gas supply connected to the housing near the first and second legs; an exhaust volume in the housing between the central portion thereof and the processing chamber, the exhaust volume having an exhaust pump connected thereto; and a counterflow tube extending from the central portion of the housing to the exhaust system, the tube being concentric with and surrounding a portion of the first path between the central portion and the exhaust volume. 9. The plasma monitor of claim 8 wherein: the at least two windows in the housing includes a third window located in the reference signal path between the central cavity and the reference signal source; the plurality of radially extending legs includes a third leg extending from the central cavity to the third window and surrounding a portion of the second path. 10. A vacuum processing apparatus comprising the plasma monitor of claim 8. 11. A vacuum processing apparatus comprising a processing chamber, the plasma monitor of claim 8 and a controller programmed to control plasma parameters within the processing chamber in response to a plasma emissions measurement signal from the plasma monitor. 12. A semiconductor wafer processing apparatus comprising: a vacuum processor including a plasma processing chamber having a plasma volume therein; a plasma energy source coupled to the plasma volume; a substrate support in the chamber facing the plasma volume; a plasma monitor having a vacuum tight housing connected to a plasma processing chamber and having at least two line-of-sight signal paths therethrough, including a monitoring signal path and a reference signal path, the plasma monitor further including: at least two windows in the housing, including a first window located in the monitoring signal path and a second window located in the reference signal path; a reference signal source; at least two optical sensors including a first sensor located outside of the window in the monitoring signal path and one located outside of the window in the reference signal path and oriented to receive and measure signals in the respective paths; the monitoring signal path extending from the processing chamber through the housing and the first window, to the first sensor, and the reference signal path extending from the reference signal source, through the housing and the second window, to the second sensor; a plurality of baffles along each path to substantially equally affect the flow of film forming material to the respective first and second windows; a central cavity centered on a point of intersection of the first and second paths; the housing being configured in a plurality of radially extending legs, including a first leg extending from the central cavity to the first window and surrounding a portion of the first path and a second leg extending from the central cavity to the second window and surrounding a portion of the second path; a purge gas supply connected to the housing near the first and second legs; an exhaust volume in the housing between the central portion thereof and the processing chamber, the exhaust volume having an exhaust pump connected thereto; and a counterflow tube extending from the central portion of the housing to the exhaust system, the tube being concentric with and surrounding a portion of the first path between the central portion and the exhaust volume. the at least two windows in the housing includes a third window located in the reference signal path between the central cavity and the reference signal source; the plurality of radially extending legs includes a third leg extending from the central cavity to the third window and surrounding a portion of the second path; and a control system responsive to outputs from the first and second sensors, and programmed to derive a measurement of emissions from the plasma volume by adjusting output from the first sensor in accordance with output of the second sensor and to control a plasma within the plasma processing chamber in response to the measurement.
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