Method and system of compressing raw fabrication data for fault determination

• US 8,510,610 B2
• Filed: 09/22/2011
• Issued: 08/13/2013
• Est. Priority Date: 06/22/2011
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Inotera Memories Incorporated (Micron Technology, Inc.)
• Inventors: Chu, Yij Chieh, Tian, Yun-Zong
• Primary Examiner(s): Ton, David
• Application Number:
  US13/240,305
• Publication Number:
  US 20120331357A1
• Time in Patent Office: 691 Days
• Field of Search: 702/182, 216/59, 703/2, 700/83, 700/108, 700/121, 714/708
• US Class Current: 714/708
• CPC Class Codes: G05B 23/0254 based on a quantitative model, e.g. mathematical relationships between inputs and outputs; functions: observer, Kalman filter, residual calculation, Neural Networks
• CPC Class Codes: G06F 11/0754 by exceeding limits
• CPC Class Codes: G06F 11/3013 where the computing system is an embedded system, i.e. a combination of hardware and software dedicated to perform a certain function in mobile devices, printers, automotive or aircraft systems testing or monitoring of control systems or parts thereof G05B23/02
• CPC Class Codes: G06F 11/3082 the data filtering being achieved by aggregating or compressing the monitored data

Abstract

The instant disclosure relates to a raw data compression method for the fabrication process. The method includes the steps of: inputting into a signal converter a collection of raw data points representing operational parameter of a semiconductor equipment within a predetermined time period; obtaining an approximation of the raw data points with a Fourier series; computing the Fourier coefficients and the residuals between the raw data points and the corresponding predicted values predicted by the Fourier series; determining if the residuals exceed an error threshold; recording and storing the Fourier coefficients as the compressed data if none of the residuals exceeds the error threshold; and recording the raw data point as abnormal data point if the corresponding residual exceeds the error threshold before recording and storing the Fourier coefficients and the abnormal data point as the compressed data.

Claims

1. A method of compressing raw data representing an operational parameter of a semiconductor manufacturing equipment for fault determination, comprising the steps of:

inputting into a signal convertor a collection of raw data points representing operational parameters of the semiconductor manufacturing equipment within a predetermined time period;

obtaining an approximation of the raw data points with a Fourier series by the signal converter;

computing the Fourier coefficients and the residuals between each of the raw data points and the corresponding predicted values by the Fourier series;

determining if the residuals exceed an error threshold; and

if none of the residual exceeds the error threshold, recording and storing in a data storage device the Fourier coefficients as the compressed data;

if the corresponding residual exceeds the error threshold, recording in the data storage device the raw data point as abnormal data point before recording and storing the Fourier coefficients and the abnormal data point as the compressed data.

2. The method of compressing raw data representing an operational parameter of a semiconductor manufacturing equipment for fault determination of claim 1, wherein the raw data points are collected by a fault detection and classification (FDC) system.

3. The method of compressing raw data representing an operational parameter of a semiconductor manufacturing equipment for fault determination of claim 2, wherein the raw data points display periodic behavior.

4. The method of compressing raw data representing operational parameter of a semiconductor manufacturing equipment for fault determination of claim 1, wherein the signal converter uses the least squares method to compute the Fourier coefficients in obtaining a waveform function ƒ

(x), wherein the waveform function ƒ

(x) is defined as;

5. The method of compressing raw data representing operational parameter of a semiconductor manufacturing equipment for fault determination of claim 1, wherein the recording process of the raw data point whose residual exceeds the error threshold as abnormal data point is performed by a signal detector disposed within the signal converter.

6. The method of compressing raw data representing operational parameter of a semiconductor manufacturing equipment for fault determination of claim 1, further comprising a restoration step and a displaying step, wherein the restoration step involves restoring an original waveform of measured raw data, and wherein the displaying step shows the restored waveform on a displaying device.

7. The method of compressing raw data representing operational parameter of a semiconductor manufacturing equipment for fault determination of claim 6, wherein the displaying step shows the compressed data points directly on the displaying device.

8. A system for compressing raw data from a semiconductor manufacturing equipment, comprising:

a signal converter for gathering a collection of raw data points from the semiconductor manufacturing equipment within a predetermined time period, for approximating the raw data points by a Fourier series, for computing the Fourier coefficients and the residuals between the raw data points and the corresponding predicted values by the Fourier series, and for determining if any residual exceeds an error threshold;

a data storage device electrically coupled to the signal converter, wherein the data storage device is used to record and store the Fourier coefficients as the compressed data;

a waveform restoration device coupled electrically to the data storage device, wherein the waveform restoration device is used to restore the original waveform of the measured data from the compressed data.

9. The system for compressing raw data from a semiconductor manufacturing equipment of claim 8, wherein the signal converter includes a signal detector coupled electrically thereto, wherein the signal detector detects and records any raw data point, whose residual exceeds the error threshold, as an abnormal data point.

10. The system for compressing raw data from a semiconductor manufacturing equipment of claim 9, wherein the data storage device records and stores the Fourier coefficients and all abnormal data points as the compressed data.