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Reactive Sputtered Titanium Nitride with Excess Nitrogen as a Chemical Vapor Deposited Tungsten Adhesive Layer

IP.com Disclosure Number: IPCOM000037951D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Lee, PP: AUTHOR [+2]

Abstract

A titanium nitride composition is shown which allows complete removal of a semiconductor wafer's backside film during tungsten cap strip while insuring good tungsten to insulator adhesion.

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Reactive Sputtered Titanium Nitride with Excess Nitrogen as a Chemical Vapor Deposited Tungsten Adhesive Layer

A titanium nitride composition is shown which allows complete removal of a semiconductor wafer's backside film during tungsten cap strip while insuring good tungsten to insulator adhesion.

Because a chemical vapor deposited (CVD) tungsten (W) film has poor adhesion to insulator surfaces, e.g., BPSG, PSG, TOX, SiNy, etc., an adhesion layer is required between tungsten and insulator. Titanium nitride (TiN), formed by thermal annealing a thin titanium film in a nitrogen ambient, is recognized as good adhesive and contact barrier for CVD W. The annealed TiN layer also prevents tungsten from flaking on the backside of wafers. Because tungsten is readily oxidized at deposition temperatures between 400oC and 550oC, a cap layer over the CVD W film is used to prevent formation of tungsten oxide during wafer unloading from a CVD tool. This cap layer is subsequently stripped in a wet strip solution. Due to the conformal deposition characteristics of CVD W, deposition occurs on both front and back sides of wafers. A wafer backside particulate problem results when blanket deposited CVD W is subjected to a wet etch, especially during the cap strip operations. By altering the structure and composition of the adhesion layer on the backside of wafers, particulate problems are completely eliminated.

By utilizing a reactive sputtered TiN with excess nitrogen present, the r...