AVS 53rd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS1-TuP

Paper PS1-TuP8
Selective Etching of Titanium Nitride

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Etching of High-K, Compound Semiconductors and Advanced Materials Poster Session
Presenter: D.J. Wu, Air Products and Chemicals, Inc.
Authors: D.J. Wu, Air Products and Chemicals, Inc.
E.J. Karwacki, Air Products and Chemicals, Inc.
Correspondent: Click to Email
Titanium nitride (TiN) has many emerging new applications within semiconductor industry. For example, it is already being employed as a metal electrode in DRAM devices, and as a barrier material within logic devices. TiN film can be made using either chemical vapor deposition or atomic layer deposition based processes, where a quartz tube furnace is often used as the deposition reactor. After film deposition, a cleaning process is typically utilized to remove TiN residues. The cleaning process needs to be fast enough to meet the requirements in high volume manufacturing and selective enough to prevent damage to the underlying quartz. Damage such as etching of the quartz will cause surface roughening that may then interfere with heat transfer through the quartz walls to wafers within the reactor. Using a lab reactor with both thermal and remote plasma capabilities, a variety of reactive gases and process conditions were screened for selectively etching TiN. In this paper we report on our development of two thermally assisted processes: a plasmaless process using XeF2 and a remote-plasma process utilizing NF3 in combination with xenon. The XeF2 process provides high etch selectivity for TiN vs quartz at a moderate TiN etch rate. The remote plasma process using NF3 and Xe increases the etch selectivity by an order of magnitude and doubles the etch rate when compared to a NF3 only remote plasma process.