Browse Prior Art Database

Sputtered Metal Local Interconnect Process

IP.com Disclosure Number: IPCOM000103584D
Original Publication Date: 1993-Jan-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Gut, GM: AUTHOR [+2]

Abstract

This article describes a technique by which a local interconnect process for integrated circuit processing can be implemented. The novel features of this technique are that the material used for the interconnect is not subtractively etched; rather, it is patterned using a liftoff process. The special liftoff process also permits sputtered films to be used for the interconnect material.

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Sputtered Metal Local Interconnect Process

       This article describes a technique by which a local
interconnect process for integrated circuit processing can be
implemented.  The novel features of this technique are that the
material used for the interconnect is not subtractively etched;
rather, it is patterned using a liftoff process.  The special liftoff
process also permits sputtered films to be used for the interconnect
material.

      Semiconductor wafers are prepared for local interconnect
formation with the desired devices exposed, as shown in Fig. 1.

      The wafers are coated with layers of silicon nitride (300 A)
and PECVD silicon dioxide (2000 A), as shown in Fig. 2.

      The wafers are coated with photoresist (15000 A) and are
patterned as desired.  The resist is UV hardened to prepare it for
further processing.  A reactive ion etch (RIE) process is then
performed to etch uniformly and anisotropically through 90 percent of
the oxide thickness.  This is followed by a short buffered HF wet
etch of the remaining oxide layer.  This serves to expose the nitride
and to form a narrow crevice under the photoresist (PR) pattern.
This is the key step which permits later liftoff of the sputtered
metal.  These steps are shown in Fig. 3.

      A second RIE step is performed, this time to etch through the
silicon nitride layer.  This thin layer is removed uniformly with
minimal substrate attack.  Nitride penetration is followed by
sputte...