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Browse Prior Art Database

Integrated Device Conductor Contact Formation

IP.com Disclosure Number: IPCOM000085473D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Schnitzel, RH: AUTHOR [+2]

Abstract

It has been proposed in the formation of metallization on integrated chips to coat a photoresist, as by evaporation, with an intermediate metal layer (such as chrome under Cu/Al alloy), to enhance the further deposition of contact metallurgy. However, the tensile stresses induced in the deposited chrome are reflected, on cooling, in a phenomena called "curling", in which lateral portions of the chrome layer shear from glass overhang on the photoresist and warp upwardly.

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Integrated Device Conductor Contact Formation

It has been proposed in the formation of metallization on integrated chips to coat a photoresist, as by evaporation, with an intermediate metal layer (such as chrome under Cu/Al alloy), to enhance the further deposition of contact metallurgy. However, the tensile stresses induced in the deposited chrome are reflected, on cooling, in a phenomena called "curling", in which lateral portions of the chrome layer shear from glass overhang on the photoresist and warp upwardly.

It has been found that such "curling" on chrome layer 3 can be suppressed by depositing it via a sputtering technique at room temperature as described below. The process comprises the deposition of a first resist layer 4, as for example of AZ* 1350 J (10:1) positive resist, overcoated with a glass 2 plus a second resist layer 5, as for example organo silicone plus AZ 1350 J or AZ 111 (pmma can also be used), and exposing the layers with Prafe or Microtek or E- beam units.

After exposure, the resist layers 4 and 5 are developed and include sequential treatments with reactive ion etch and buffer etching to provide access openings 6, as shown illustratively in Fig. 2.

A chrome layer 3, as for example 1000 angstroms thick, is deposited below the conductor pattern from a standard 8 inch diameter chromium target in a DC triode type sputtering system. The deposition has been effected at one micron argon pressure and 800 volts target voltage with a chrome depo...