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Method for charge induced in-place protection of metal during wet etching and cleaning

IP.com Disclosure Number: IPCOM000030177D
Publication Date: 2004-Jul-30
Document File: 3 page(s) / 69K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for charge induced in-place protection of metal during wet cleaning. Benefits include improved functionality.

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Method for charge induced in-place protection of metal during wet etching and cleaning

Disclosed is a method for charge induced in-place protection of metal during wet cleaning. Benefits include improved functionality.

Background

      Back-end (BE) cleans of cobalt (Co) cap-containing wafers are required for integration without etch stop (ES-less integration).

      In conventional ES-less integration at the back end of the manufacturing line, metal is exposed after the via etch or trench etch (see Figures 1 and 2).

      Most of the chemistries that are used for photoresist (PR) removal are oxidizing in nature (based on peroxides), and are incompatible with metals.

General description

      The disclosed method is in-place metal protection during wet cleaning at the backend of the manufacturing line, using via and trench cleaning steps. Metals include copper (Cu) and Co.

              The key elements of the disclosed method include:

•             Cleanability of metal-exposed via and trench wafers in the ES-less integration without loss or attack of the metal

•             Cleaning solution that has an ionic salt of an oxacid

•             One of the anionic species that is an oxacid, such as OCl- (hypochlorate), with high charge density that is attracted towards the metal (Cu or Co) on the wafer

•             Cationic species in the chemical solution with one being organic, such as TMA+, that can be attracted to the negatively charged metal (due to the previously adsorbed OCl-)

•             Aqueous solution or solvent-based, depending on the anion (oxo...