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Develop End Point Detection Control Algorithm

IP.com Disclosure Number: IPCOM000088231D
Original Publication Date: 1977-May-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 7 page(s) / 193K

Publishing Venue

IBM

Related People

Smith, EG: AUTHOR

Abstract

Presented herein is control software for use in defining the end of development processes for delineating first level metallurgy resist geometries. Also, the algorithm reported here can be employed to enhance other development processing steps, for example, quartz via hole operations.

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Develop End Point Detection Control Algorithm

Presented herein is control software for use in defining the end of development processes for delineating first level metallurgy resist geometries. Also, the algorithm reported here can be employed to enhance other development processing steps, for example, quartz via hole operations. Nomenclature ISW Logic parameter, 1 signifies algorithm has been initialized IARM Specifies which wafer etch tank in automatic tool is being used (A-tank or B-tank) INUM Pointer for automatic tool control software (the calling software) to which algorithm to use IRC Signifies automatic tool wafer quenching startup if equal to 0, continue wafer etching otherwise IV Fixed point reflectivity measurement K Reflectivity extrema counter KOUNT Tracks number of consecutive times process end-point criterion is satisfied KBOUND Denotes upper bound on KOUNT THICK Estimation of photoresist film thickness removed C2, Smoothed value of reflectivity time derivative, current C2LAST and past values, respectively DELTAT Data sampling period (in secs.) P Maximum (+P) and minimum (-P) photoresist film initial thickness tolerance factor THICKO Initial photoresist film thickness estimate NMAX Reflectivity data "window" DTHICK Estimated photoresist thickness corresponding to each reflectivity waveform cycle (fringe) I Reflectivity data sample counter W(L,J,K) J-th set of filter weights (J=1,2) corresponding to L-th develop processing tank (L=1,2), K=1,2,...,NMAX Details for Node A (appearing in the drawing) follow. After entering Node A, the following parameters are initialized as shown:. CELL(LL,J) = 0.,...