Browse Prior Art Database

Deposition Precursors for Semiconductor Applications

IP.com Disclosure Number: IPCOM000200097D
Publication Date: 2010-Sep-27
Document File: 3 page(s) / 54K

Publishing Venue

The IP.com Prior Art Database

Abstract

Organometallic compounds comprising at least one metal or metalloid and at least one fully or partially substituted allyl group having sufficient substitution to impart increased thermal stability or increased shelf life. These organometallic compounds are useful as chemical vapor deposition or atomic layer deposition precursors in semiconductor applications.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 41% of the total text.

Page 01 of 3

Deposition Precursors for Semiconductor Applications

ABSTRACT

Organometallic compounds comprising at least one metal or metalloid and at least one fully or partially substituted allyl group having sufficient substitution to impart increased thermal stability or increased shelf life. These organometallic compounds are useful as chemical vapor deposition or atomic layer deposition precursors in semiconductor applications.

DESCRIPTION

There is a continuing need for thermally stable chemical vapor deposition/atomic layer deposition precursors that have longer shelf life at room temperature. A ubiquitous ligand family for such precursors is that containing the mono-anionic conjugated hydrocarbons. Perhaps the most noted is the cyclopentadienyl ion (Cp), where the aromatic structure provides significant stabilization. A related species is the linear diene ion, and further the three-membered system known as an allyl. The allyl ligand (C3H5-) can be found in a number of potential precursors, including those for W, Pd, Ni, and Pt. It has a low molecular weight and finds use in reductive eliminations of organics to produce metal films.

One concern for these allyl systems, however, is shelf life. Although their high reactivity makes them excellent for low temperature deposition, this same reactivity often makes storing these compounds at ambient temperatures difficult. For example, compounds such as (allyl)Pd(cyclopentadienyl) and [(2- methylallyl)Ni(Cl)]2 require cold storage. Substitution at the terminal position
may increase stability, but if these substituents are not identical, other drawbacks can result.

Comparisons between (2-methylallyl)palladium(fod) and (2-tert- butylallyl)palladium(fod) were made in an inert atmosphere at various temperatures in darkness. Although the compounds do not appear to be significantly light sensitive, the control was needed to compare more accurately with compounds kept in a freezer. While the 2-methylallyl analog displayed little change after 1 week at -40ºC, there was significant darkening (yellow to yellowish brown) at room temperature after a couple of days. In contrast, the 2- tert-butylallyl analog displayed no significant darkening after weeks at both cold and room temperatures.

Common nickel precursors suffer from high toxicity (e.g., Ni(CO)4) and low thermal stability (e.g., NiCp2). Compounds of the type (allyl)NiCp are known, but may suffer from premature reductive elimination or allyl isomerization. Thus, generating a (2-tert-butylallyl)(Cp)Ni system may in fact be an excellent precursor for nickel-containing films. An acetylacetonate derivative may also prove useful.

It should be noted that when comparing known compounds, the (allyl)M(β- diketonate)complexes (where M = a metal such as Pd) are reported to be more

Page 1 of 3


Page 02 of 3

stable than the analogous (allyl)M(cyclopentadienyl) complexes (thus the impetus for moving to the β-diketonate ligands). Although the same trend is expect...