Browse Prior Art Database

POST W CMP CLEAN

IP.com Disclosure Number: IPCOM000007787D
Original Publication Date: 1996-Aug-01
Included in the Prior Art Database: 2002-Apr-24
Document File: 1 page(s) / 51K

Publishing Venue

Motorola

Related People

Papu D. Maniar: AUTHOR [+2]

Abstract

Advanced multi-level metal technologies being developed in research and development laboratories use oxide chemical mechanical polishing (CMP) to planarize an inter-level dielectric (ILD) and tung- sten (w) CMP to define the W interconnect via plugs. The simplified integration is: deposit and pattern bottom metal; deposit and CMP planarize ILD, etch vias; deposit W fill after necessary glue layer; define the via plug by polishing the excess W and the glue layer that lies outside the vias; and deposit and pat- tern an overlying metal layer.

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Technical Developments

POST W CMP CLEAN

by Papu D. Maniar and Kathleen Perry

  Advanced multi-level metal technologies being developed in research and development laboratories use oxide chemical mechanical polishing (CMP) to planarize an inter-level dielectric (ILD) and tung- sten (w) CMP to define the W interconnect via plugs. The simplified integration is: deposit and pattern bottom metal; deposit and CMP planarize ILD, etch vias; deposit W fill after necessary glue layer; define the via plug by polishing the excess W and the glue layer that lies outside the vias; and deposit and pat- tern an overlying metal layer.

  A problem occurs when a photo process for the overlying metal layer attempts to align to the under- lying via level. Photo alignment keys typically are filled with W CMP residue that smoothens out the top metal step coverage which in turn reduces the

photo alignment signal and, in an extreme case, alto- gether eliminates the alignment key recognition. A solution to this problem is to clean up the align- ment keys afler W CMP process to eliminate any residue present. Many cleans, BOE, surfactant megasonic, deionized (DI) water megasonic, hot DI water, photo developer, oxygen furnace anneal, and dilute HF solution were unsuccessmlly attempted. A successful clean up of the residue was possible using a hydrogen-peroxide solution. A two minute, 30% H202 solution at room temperature completely cleaned up any residue in the alignment keys. This two minute cle...