Browse Prior Art Database

Carbon in Copper Grain Boundaries to Inhibit Diffusion and Electromigration

IP.com Disclosure Number: IPCOM000104306D
Original Publication Date: 1993-Apr-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Allen, RD: AUTHOR [+5]

Abstract

Disclosed is the addition of Carbon in a Copper host thin film to inhibit diffusion and electromigration. This material which exhibits low electrical resistivity and resistance to both electromigration and intergranular diffusion makes it suitable for line interconnects and electrical contacts where high current densities are present. This system can also be utilized as a diffusion barrier placed between layers to prevent diffusion between the layers.

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Carbon in Copper Grain Boundaries to Inhibit Diffusion and Electromigration

      Disclosed is the addition of Carbon in a Copper host thin film
to inhibit diffusion  and  electromigration.  This material which
exhibits  low  electrical  resistivity  and resistance to both
electromigration and intergranular diffusion  makes  it  suitable
for  line  interconnects and electrical  contacts  where  high
current densities are present.  This  system  can  also be utilized
as a diffusion barrier placed between layers to prevent  diffusion
between the layers.

      The  films  are  produced by co-sputtering Carbon and Copper
using a Radio Frequency (13.56  MHz) induced Argon Plasma with
relatively high concentrations of Carbon (i.e., sputter target area
ratios of 20/80 and 50/50  Carbon/Copper).  Suitable substrates
include Magnesium  Oxide, Silicon Dioxide, Silicon, and Gold on
Magnesium Oxide.  The temperature of the substrate platform ranges
from 20ºC to 120ºC.  Analysis include Transmission Electron
Microscopy (TEM), Electron Energy Loss Analysis (EELS), and a Four
Point Resistance Measuring Probe.

      Results  show  that  the  as  deposited  films  have  Carbon
precipitated out into the grain boundaries  of  the  Copper.  The
Carbon found at these boundaries is in proportion to the Carbon
target area.  Carbon presence in the grain boundaries makes it a
strong contender to inhibit  electromigration  in Copper.

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