Growth Rate Enhancement for High Rate, Low Temperature Selective/ Blanket Tungsten
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Joshi, RV: AUTHOR [+1]
Described is a fabrication method which is designed to enhance the growth rate of selective tungsten at low temperatures for use in integrated circuit technology.
Growth Rate Enhancement for High Rate, Low Temperature
a fabrication method which is designed to enhance
the growth rate of selective tungsten at low temperatures for use in
integrated circuit technology.
Selective tungsten has been found to
metallization via filling, contact metallurgy, etc. However, prior
art required temperatures above 500~C and produced large quantities
hydrofluoric acid (HF) which degraded the junction qualities and
produced worm holes and tunnels. The concept described herein
provides a fabrication process that avoids the degradation problems
as well as improves the growth rate, adhesion and stress.
involves the use of disilane. The gas
can be used as follows:
7WF + 6SiF4 + 18HF
At higher temperatures:
7WF6 + 3Si2H6--->7SELECTIVEW + 6SiF4 + 18HF
At lower temperatures:
4WF6 + 3Si2H6 --> 4W + 6SiF4 + 9H2
The ratios of
Si2H6/WF6 should be less than 2. The
e is workable for cold wall reactors having selective tungsten
deposition capability. Disilane is more effective than silane
because of its reactivity and it contains two atoms of silicon which
generate SiF4, such that the HF is minimized. Also, the
decomposition temperature of disilane is much lower than the silane
decomposition temperature. As a result, the process works below
400~C at high...