RF matching network with distributed outputs

Details RF matching network with distributed outputs RF matching network with distributed outputs

2001-11-01

2003-04-22

Walberg, Teresa (Department: 3742)

Electric heating

Metal heating

By arc

C333S017300, C118S7230ER

Reexamination Certificate

active

06552297

ABSTRACT:

BACKGROUND
This invention relates to systems and methods of film deposition, and more particularly, to improved systems and methods for depositing a high quality film onto a large area substrate.
In recent years, liquid crystal cells have been developed to form high quality displays that are light-weight and consume low power. These liquid crystal cells typically include two glass substrates with a layer of a liquid crystal material sandwiched therebetween. Electrically conductive films are patterned on the substrates to form circuit elements such as thin film transistors (TFTs). The substrate can be connected to a power source to change the orientation of the liquid crystal material such that various regions of the liquid crystal display can be selectively energized using the TFTs.
Reactors for depositing films onto the large area glass substrates typically deploy plasma enhanced chemical vapor deposition (PECVD) equipment. A high frequency power supply is typically used to induce a breakdown of process gases within the PECVD process chamber. As glass substrates are typically much larger than silicon substrates, the dimensions of the electrode may approach the quarter-wavelength of the power supply frequency. Such conditions lead to an uneven discharge of electrical energy over the surface of the large substrate. This non-uniform voltage distribution can result in an uneven film deposition on the substrate surface.
Traditional solutions to the uneven film deposition have involved adjusting various process variables, including pressure, gas composition, flow rate, radio frequency (RF) power level, and electrode spacing, among others. Adjusting these process variables works well for relatively small substrates. However, as the size of the substrate, the size of the chamber and the frequency of the power supply increase, the film deposited on the substrate may be non-uniform.
SUMMARY
In general, in one aspect, an apparatus is disclosed for distributing RF power outputs to a first electrode in a parallel plate electrode system for generating plasma in depositing films on a substrate. The apparatus includes a RF power supply and a matching network coupling the RF power supply to multiple points distributed on the first electrode.
In some implementations, the RF outputs are coupled directly to a backing plate which serves as the electrical connection between outputs from one or more matching networks and a shower head.
In one exemplary implementation, the apparatus includes a load capacitor for receiving a radio frequency power input and an inductor having first and second ends, with the first end coupled to the load capacitor. The apparatus also includes multiple drive capacitors each of which electrically couples the second end of the inductor to a different one of multiple points distributed on the first electrode.
In some implementations, the capacitance of each drive capacitor is user-selectable. Similarly, in some implementations, the points on the first electrode to which the drive capacitors are coupled are user-selectable. Such features allow a user to adjust the values of the drive capacitors as well as the locations of the points on the first electrode to which the drive capacitors are coupled to improve the uniformity of the deposited film.
The apparatus can be incorporated into a system for depositing a thin film, where the system also includes, for example, a vacuum chamber in which a substrate to be processed and the first electrode are positioned, a process gas source coupled to the first electrode to introduce a gas stream into the chamber, and a heater for heating the substrate in the chamber.
The distributed impedance matching network can be used in various plasma enhanced processing systems which include one or more RF power supplies. In systems having multiple power supplies, the distributed matching network can be used to couple, for example, a high frequency power supply to the first electrode.
In another aspect, a method of processing a thin film on a substrate includes providing a radio frequency power input to a load capacitor and an inductor where the inductor is coupled to multiple drive capacitors, and applying an output of each respective drive capacitor to a different one of multiple points distributed on an electrode. In some implementations, the capacitance of each drive capacitor can be adjusted to arrive at a composite predetermined value. As previously noted, the values of the drive capacitors as well as the locations of the points on the electrode to which the drive capacitors are coupled can be adjusted to improve the uniformity of the deposited film.
Various implementations include one or more of the following advantages. By supporting movable tie points from the RF power supply outputs to the electrode, the system provides a spatial control variable which allows a user to select or adjust the locations on the electrode to which the drive capacitors are coupled electrically. Additionally, by allowing a user to select the individual values of the capacitors, the system provides an electrical control variable. The spatial control variable and the electrical control variable supplement the traditional process variables, including pressure, gas composition, flow rate, RF power level, and electrode spacing such that more uniform films are deposited. Substantially uniform films interface better to subsequently deposited layers. Other film properties such as density and stress also are improved, and a high deposition rate can be achieved.
Other features and advantages of the invention will become apparent from the following description, including the drawings and claims.


REFERENCES:
patent: 3475702 (1969-10-01), Ainsworth
patent: 3569777 (1971-03-01), Beaudry
patent: 3594295 (1971-07-01), Meckel et al.
patent: 3675093 (1972-07-01), Russo et al.
patent: 3872278 (1975-03-01), Boom
patent: 4229826 (1980-10-01), Wanzer
patent: 4272743 (1981-06-01), Evans
patent: 4284490 (1981-08-01), Weber
patent: 4336118 (1982-06-01), Patten et al.
patent: 4362632 (1982-12-01), Jacob
patent: 4626312 (1986-12-01), Tracy
patent: 4661228 (1987-04-01), Mintz
patent: 4712112 (1987-12-01), Carr
patent: 4716491 (1987-12-01), Ohno et al.
patent: 4792732 (1988-12-01), O'Loughlin
patent: 4854263 (1989-08-01), Chang et al.
patent: 4871421 (1989-10-01), Ogle et al.
patent: 4891087 (1990-01-01), Davis et al.
patent: 4918031 (1990-04-01), Flamm et al.
patent: 4941915 (1990-07-01), Matsuoka et al.
patent: 4966669 (1990-10-01), Sadamori et al.
patent: 4990229 (1991-02-01), Campbell et al.
patent: 4999096 (1991-03-01), Nihei et al.
patent: 5122251 (1992-06-01), Campbell et al.
patent: 5146137 (1992-09-01), Gesche et al.
patent: 5178739 (1993-01-01), Barnes et al.
patent: 5186718 (1993-02-01), Tepman et al.
patent: 5192849 (1993-03-01), Moslehi
patent: 5195045 (1993-03-01), Keane et al.
patent: 5234560 (1993-08-01), Kadlec et al.
patent: 5241245 (1993-08-01), Barnes et al.
patent: 5280154 (1994-01-01), Cuomo et al.
patent: 5292393 (1994-03-01), Maydan et al.
patent: 5304279 (1994-04-01), Coultas et al.
patent: 5346578 (1994-09-01), Benzing et al.
patent: 5361016 (1994-11-01), Ohkawa et al.
patent: 5366585 (1994-11-01), Robertson et al.
patent: 5392018 (1995-02-01), Collins et al.
patent: 5397962 (1995-03-01), Moslehi
patent: 5401350 (1995-03-01), Patrick et al.
patent: 5404079 (1995-04-01), Ohkuni et al.
patent: 5418431 (1995-05-01), Williamson et al.
patent: 5424691 (1995-06-01), Sadinsky
patent: 5429070 (1995-07-01), Campbell et al.
patent: 5429995 (1995-07-01), Nishiyama et al.
patent: 5430355 (1995-07-01), Paranjpe
patent: 5431799 (1995-07-01), Mosely et al.
patent: 5473291 (1995-12-01), Brounley
patent: 5503676 (1996-04-01), Shufflebotham et al.
patent: 5571366 (1996-11-01), Ishii et al.
patent: 5573595 (1996-11-01), Dible
patent: 5585766 (1996-12-01), Shel
patent: 5591493 (1997-01-01), Paranjpe et al.
patent: 5639357 (1997-06-01), Xu
patent: 5643364 (1997-07-01), Zhao et al.
patent: 5683537 (1997-11-01), Ishhi
patent: 5688357 (1997-11-01), Hanawa
patent: 5689215 (1997-11-01

Affiliated with

Also associated with

Rating

RF matching network with distributed outputs does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with RF matching network with distributed outputs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and RF matching network with distributed outputs will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3084887