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Patent for License:

Tuning Method for a Processing Machine    

A method for setting at least one selected parameter of a processing tool. The processing tool is utilized for processing articles in a production line.


Initially, the selected parameter is set to an initial value and one such article is positioned for processing. The article is sequentially processed by the processing tool a certain number of times and corresponding processed data are obtained. The processed data are analyzed so as to determine whether or not the processed data satisfy predetermined result criteria. Upon detecting that the processed data do not satisfy the result criteria, the selected parameter is changed to a tuned value and the processing, obtaining the processed data and analyzing thereof, are repeated as many times as required until the result criteria is satisfied.

There is need to substantially reduce or overcome disadvantages by a novel method for tuning a processing machine suitable for the conditions of a specific process.
It should be noted that for convenience of explanation only the description refers by way of example only to tuning of inspection tools that inspect wafers. The technology is by no means bound to this specific example.
There is provided according to the technology a method for setting at least one selected parameter of a processing tool that is utilized for processing articles in a production line, comprising:
a) setting said at least one selected parameter to an initial value;
b) processing an article by the processing machine and obtaining processed data indicative of features of the article, wherein said processing and obtaining the processed data are repeated a certain number of times;
c) analyzing the so obtained processed data so as to determine whether or not the processed data satisfy a predetermined result criteria;
d) upon detecting that the processed data do not satisfy the result criteria, tuning said at least one selected parameter to a tuned value; and
e) applying said steps (b), (c) and (d) as many times as required until said result criteria is essentially satisfied.
The underlying idea of the technology is to exploit the fact that inspection of articles, especially semiconductor wafers, has a statistic nature. Accordingly, several inspection procedures applied to same article, normally give rise to different inspection results. In this specific case of an optical inspection in order to locate defects, successive inspection runs provide different lists of possible defects. To this end, a certain results criteria is set, in order to determine a desired sensitivity level. Thus, for example, the result criteria may prescribe an acceptable tolerance between the inspection results obtained by a certain number of inspection procedures.
It is appreciated that the processing machine may be of any kind capable of performing inspection of articles, such as optical inspection, metrology, etc. Such a machine typically comprises illuminator and detector units and suitable light directing optics. By way of one non limiting example, the parameters which are to be set may include any one or a combination of the power of a light source used in the illuminator unit, the sensitivity of the detector unit, the autofocusing factor of the directing optics, etc. Additionally, the selected parameters may include a decision table defining the processing results. Other parameters may be used in lieu or in addition to the specified parameters, all as required and appropriate, depending upon the particular application.
It is thus evident that numerous burdensome and time-consuming steps of a conventional tuning phase are advantageously replaced here by the several steps of a certain, quickly executable model. The latter does not require the provision of any additional equipment and significantly speeds up the tuning phase.
More specifically, the technology is used for post-process automatic optical inspection of articles progressing on a production line.

Patent Summary

U.S. Patent Classes & Classifications Covered in this listing:

Class 382: Image Analysis

This is the generic class for apparatus and corresponding methods for the automated analysis of an image or recognition of a pattern. Included herein are systems that transform an image for the purpose of (a) enhancing its visual quality prior to recognition, (b) locating and registering the image relative to a sensor or stored prototype, or reducing the amount of image data by discarding irrelevant data, and (c) measuring significant characteristics of the image.

Subclass 148: At plural magnifications or resolutions

Class 257: Active Solid-State Devices (E.G., Transistors, Solid-State Diodes)

This class provides for active solid-state electronic devices, that is, electronic devices or components that are made up primarily of solid materials, usually semiconductors, which operate by the movement of charge carriers - electrons or holes - which undergo energy level changes within the material and can modify an input voltage to achieve rectification, amplification, or switching action, and are not classified elsewhere.

Subclass E21.525: Procedures, i.e., sequence of activities consisting of plurality of measurement and correction, marking or sorting steps (EPO)