Use of Standard Size Evaporators for Small Angle Metal Deposition On Large Wafers
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
The source-to-wafer distance (consequently the evaporator height) is defined by the angle of metal deposition required by the wafer process.
Use of Standard Size Evaporators for Small Angle Metal
On Large Wafers
source-to-wafer distance (consequently the evaporator
height) is defined by the angle of metal deposition required by the
to keep the same deposition angle, going from 125
mm wafer diameter to 200 mm will increase the evaporator height by a
bigger and more powerful sources have to be developed
to allow the conservation of deposited metal thickness and rate.
of this disclosure is to show how existing medium
size evaporators, along with present sources can be used to insure
with a moderate investment the same process parameters.
The basic ideas are:
a) Place the evaporation source out of the wafer center line.
b) Restrict the evaporation flux by the help of a circular aperture
in a fix shield placed in front of the wafer.
of the system (see the figure):
- the wafer is placed in a holding device 2 coupled with the
evaporator dome rotating shaft 1. This will allow the wafer to rotate
around its center which is on the center line of the evaporator.
- a rigid fix shield 3 having a circular aperture radius R is closed
to the wafer active side. This shield is located to have the diameter
of the hole on the diameter of the wafer and the outer side of the
hole tangent with the edge of the wafer (the distance between the
shield and the wafer being...