Age-based double EWMA controller and its application to CMP processes

Author

Chen, Argon ; Guo, Ruey-Shan

Author_Institution

Inst. of Ind. Eng., Nat. Taiwan Univ., Taipei, Taiwan

Volume

14

Issue

1

fYear

2001

fDate

2/1/2001 12:00:00 AM

Firstpage

11

Lastpage

19

Abstract

In the originally proposed run-by-run control scheme, the EWMA statistic is used as an estimate of the process deviation from its target. However, the controller based on the EWMA statistic is not sufficient for controlling a wearing out process. The PCC controller has been thus proposed to enhance the run-by-run controller capability. In this paper, we first reexamine the fundamentals of the PCC formulations and propose an adjustment that is advantageous in controlling processes subject to both random shifts and drifts. The adjusted PCC controller is then further refined to take into account the process age. This age-based double EWMA scheme is then applied to the CMP process, which is known in the semiconductor industry to be rather unstable

Keywords

chemical mechanical polishing; predictor-corrector methods; statistical process control; CMP processes; PCC controller; age-based double EWMA controller; exponentially weighted moving average; predictor corrector control; process age; random shifts; run-by-run controller capability; semiconductor industry; Argon; Control systems; Electronics industry; Helium; Input variables; Optimal control; Process control; Refining; Semiconductor process modeling; Statistics;

fLanguage

English

Journal_Title

Semiconductor Manufacturing, IEEE Transactions on

Publisher

ieee

ISSN

0894-6507

Type

jour

DOI

10.1109/66.909650

Filename

909650