Method of Making Dense, Conformal, Ultra-Thin Cap Layers of Nanoporous Low-k ILD by Plasma-Assisted Atomic Layer Deposition

Reference number: STC-PS-0745
Inventor(s): C. Brinker; J. Cecchi; Y. Jiang
For more information, contact: Erin M. Beaumont (505-272-7912) or Lisa Kuuttila (505-272-7905)

Patent(s)

Application(s) pending

Background

Device Dimensions in semiconductor integrated circuits (ICs) continue to shrink. As such, low dielectric constant (low-k) materials are needed as interlevel dielectrics (ILD) to mitigate issues caused by reduce line width and line-to-line distances such as increasing RC-delay. Nanoporous materials are the most promising low-k solutions, but the open pores at the surface of a nanoporous material need to be capped to prevent contamination adsorption. To be useful in microelectronics applications, a pore-sealing coating must be conformal to the 3D topology of patterned ILD films. Existing methods for dense conformal ultra-thin capping will not only cap the open pores at the surface, but also fill up some of the internal pores in the surface vicinity, which is not desirable for low-k applications.

The use of atomic layer deposition (ALD) has enabled the production of precisely control film thickness on the nanometer scale with uniformity over large areas. These advantages have caused this method to become highly usable in membranes fabrication. However, one issue is how to conduct ALD on the top of a porous support and the other issue is that ALD is limited to inorganic materials such as oxides, noble metals or transition metals, and semiconductor alloys which limit the applications for membranes manufactures by this method.

Technology

This invention provides an innovative method of making supported organic/inorganic hybrid thin film membranes by successive surface activation and reaction. These membranes remain the advantage of ALD thin films, but increase the range of materials used and therefore the applications. In addition they can be pinhole-free or manufactured to have sub-nanometer porosities. This invention also provides a novel method for producing ultra-thin cap layers using plasma-assisted atomic layer deposition (PA-ALD). The resulted cap is on the top surface only and no internal deposition takes place. The deposition is inherently conformal with a precisely controllable thickness.

Applications/Advantages

•All advantages of traditional ALD methods; conforms to surface with uniform thickness that is easily controlled
•Creates ultra-thin membranes only a few nanometers thick for increase permeability
•Method can be used to create porous (with controlled pore size) or non-porous membranes
•Method can be used to create hybrid membranes comprising robust inorganic matrix and functional organic groups
•Allows for conformal capping of only the top surface with no internal deposition

Applications of this technology include:

•Gas separation, e.g. H2 purification
•Water purification
•Ion/proton conduction, e.g. for fuel-cell membranes
•Sensors
•Energy conversions, etc.
•Semiconductors


Nanometer-Thick Conformal Pore-Sealing of Self-Assembled Mesoporous Silica by Plasma-Assisted Atomic Layer Deposition. Ying-Bing Jiang, Nanguo Liu, Henry Gerung, Joseph L. Cecchi, & C. Jeffrey Brinker, Journal of the American Chemical Society, 2006, vol. 128, no. 14, pp. 11018-11019.

Downloads

• UNM-745 CIP PCT Published Application (141.2 KB PDF)
• UNM-745 Published Patent (346.38 KB PDF)

Related Categories

• Lithography, Semiconductor Fabrications, and Electronic Materials
• Materials, Chemistry, and Chemical Engineering