Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-09-22
2001-02-20
Sheikh, Ayaz R. (Department: 2781)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S110000, C700S121000, C700S266000, C702S035000, C702S028000, C702S027000, C714S724000, C324S537000, C324S765010, C382S149000, C382S232000
Reexamination Certificate
active
06192287
ABSTRACT:
BACKGROUND OF THE INVENTION
Semiconductor wafer fabrication equipment typically processes product wafers only 30% of the equipment's total available time (i.e., the overall equipment effectiveness (OEE) is 30%). Test wafers, scheduled and unscheduled downtime, setup, and idleness due to the lack of product or operator and other factors represent the other 70%. The use of advanced fault detection systems can improve OEE by reducing the 15% of unscheduled down time, 3% of scheduled downtime, 8% for test wafer, and 10% for setup. In current fault detection systems, a training set of tool-state data (flows, pressures, temperatures, etc.) and process-state data (optical emission, plasma power, etc.) are collected during normal operation. By collecting these data for normal runs, the tool-state and process-state data in subsequent runs can be used to determine departures from normal operation, and hence to detect a fault. While such systems have proven valuable, changes in fabrication tool components, variations in tool properties resulting from use (deposits, parts wear, etc.) or overhaul, or variations in the optical emission window, can change the range of acceptable data in normal operation. This in turn can result in false alarms, or undetected faults.
Fourier transform infrared (FTIR) spectrometry has been shown to be an ideal technique for quantitative analysis of complex mixtures of gases. The technique has been successfully used to monitor perfluorocarbon process emissions during in-situ plasma cleaning of a plasma enhanced CVD tool. (See Zazzera, L., and Reagen, W., “PFC Process Emissions Monitoring using Extractive FT-IR,” in
A Partnership for PFC Emissions Reductions,
presented at SEMICON Southwest 96, pp 55-71, (1996); and Zazzera, L., Reagen, W., and Mahal, P., “Process Emissions Monitoring During C
3
F
8
CVD Chamber Cleaning using FT-IR” in
A Partnership for PFC Emissions Reductions,
presented at SEMICON Southwest 96, pp 81-85, (1996)). Multi-component gas mixtures of CF
4
, C
2
F
6
, C
3
F
8
, SiF
4
, COF
2
, and HF were simultaneously identified and quantified using extractive FTIR spectroscopy. Automated spectral analysis software now available enables the interpretation and quantification of the complex data set required for complete on-line analysis and control. Similar spectral analysis improvements have been developed for other gas sensors such as, for example, quadrapole mass spectrometers.
SUMMARY OF THE INVENTION
It is a broad object of the present invention to provide a novel method, apparatus, and system whereby and wherein the analysis of gases produced during processing in a tool chamber can be employed for the detection of faults.
It is also a broad object of the invention to provide such a method, apparatus and system whereby and wherein such detected faults can be classified to cause or source, and curative or other appropriate process control action can be initiated.
It has now been found that certain of the foregoing and related objects of the invention are attained by the provision of apparatus for the detection of faults occurring in a tool processing chamber in which a gaseous substance is produced, and a system incorporating such apparatus. The apparatus comprises sensor means (i.e., at least one sensor) constructed for operative connection to a tool having at least one processing chamber, for receiving data from a gaseous substance produced in the chamber, and electronic data processing means operatively connected to the sensor means. The data processing means and the sensor means are programmed and constructed, respectively, for determining compositional properties of gaseous substances from data received by the sensor means; the data processing means is also programmed for storing data, for developing characteristic gas composition profiles for gaseous substances based upon their compositional properties, and for comparing different such profiles with one another. Thus, with nominal processing conditions established in the chamber of a tool to which the sensor means is operatively connected, processing in the chamber may be effected, in each of a multiplicity of preliminary runs, for the purpose of producing a result that satisfies established criteria; the result of each preliminary run may then be evaluated so as to identify each result that satisfies the established criteria, and thereby to identify each satisfactory preliminary run; a gas composition profile may be developed for the gaseous substance produced during each satisfactory run, and the resulting satisfactory composition profiles may be stored in the data processing means; at least one more run may be carried out in the tool chamber, to produce a comparison gaseous substance; a comparison gas composition profile may then be developed for the comparison substance; and the comparison gas composition profile may be compared with the satisfactory gas composition profiles to determine if the comparison profile conforms to the satisfactory profiles. In this manner the apparatus is used to determine if the “one more” run constitutes a satisfactory run or a faulty run depending, respectively, upon whether or not the defined conformity is produced. products for the determination of etch rate and depth. As another example, processing may be carried out to effect cleaning of processing chamber elements, in which application the established criteria will relate to the condition of such elements.
Additional objects of the invention are attained by the provision of a fault-detection method comprised of the steps outlined above in connection with the instant apparatus and system, by which apparatus and system the method is desirably implemented.
REFERENCES:
patent: 5711849 (1998-01-01), Flamm et al.
patent: 5759424 (1998-06-01), Imatake et al.
patent: 5877032 (1999-03-01), Guinn et al.
patent: 6046796 (2000-04-01), Markle et al.
patent: 6090302 (2000-07-01), Smith, Jr. et al.
Nelson Chad M.
Rosenthal Peter A.
Solomon Peter R.
Spartz Martin L.
Backer Firmin
Dorman Ira S.
On-Line Technologies, Inc.
Sheikh Ayaz R.
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