Browse Prior Art Database

M2 Metal Reactive Ion Etch - Overetch Monitor

IP.com Disclosure Number: IPCOM000120680D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 48K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR

Abstract

A method is shown for applying standard sheet resistance measurement techniques to optimize reactive ion etch (RIE) overetch of M2 (second metal) aluminum so as to provide early feedback for improved manufacturing control of a product utilizing M2 RIE and IV2 (second via between first and second metal) tapered vias. (Image Omitted)

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M2 Metal Reactive Ion Etch - Overetch Monitor

      A method is shown for applying standard sheet resistance
measurement techniques to optimize reactive ion etch (RIE) overetch
of M2 (second metal) aluminum so as to provide early feedback for
improved manufacturing control of a product utilizing M2 RIE and IV2
(second via between first and second metal) tapered vias.

                            (Image Omitted)

      A current method for monitoring M2 RIE aluminum overetch
utilizes in situ endpoint detect, e.g., Cl signal, at the time of M2
etch. The new method utilizes electrical measurements of a M1 (first
metal) AlCu resistivity monitor to determine the M2 RIE overetch.

      By using a M1 Van De Paw four-point probe electrical
measurement device, measurements can be made to determine the degree
of M2 RIE overetch by designing a IV2 via over the M1 device, as
shown in the figure, and by insuring that the M2 pattern is not
defined over this IV2 via. Any M2 overetch will etch into the M1
resistivity monitor and change the monitors resistance. By measuring
this resistance at the end of the M1 process and then again after the
M2 process, comparison of differences in readings will correspond to
the M2 overetch. Therefore, second layer conductor overetch is
measured by the first conductor layer by opening a via layer over
first conductor layer and allowing it to be exposed to second
conductor layer etch.

      Because of the IV2 mon...