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In Situ Adjustment of the Inclination Angle of a Rotating Sample Holder

IP.com Disclosure Number: IPCOM000120524D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Buchmann, P: AUTHOR [+3]

Abstract

In semiconductor technology evaporation is often used to deposit materials onto the structured surface of a wafer. If the substrate has a pronounced topography, the problem of edge coverage arises since evaporation from a resistively or E-beam-heated source is highly directional. A specific issue frequently encountered is that of the continuity of a conductor, an insulator or a diffusion barrier over a nearly vertical edge of an etched structure.

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In Situ Adjustment of the Inclination Angle of a Rotating Sample
Holder

      In semiconductor technology evaporation is often used to
deposit materials onto the structured surface of a wafer. If the
substrate has a pronounced topography, the problem of edge coverage
arises since evaporation from a resistively or E-beam-heated source
is highly directional. A specific issue frequently encountered is
that of the continuity of a conductor, an insulator or a diffusion
barrier over a nearly vertical edge of an etched structure.

      One solution used in single-wafer evaporation systems is to
tilt the sample holder with respect to the incident beam of
evaporated material. Best isotropy and uniformity of the film on the
wafer is achieved using sample rotation around both the axis of the
sample holder and the axis of the incident beam. The tilt angle is
usually fixed mechanically before the sample holder is installed in
the high-vacuum evaporation system.

      A special situation is given where the process requires
evaporation of two different materials at different tilt angles. If
the high vacuum has to be maintained during the whole process for the
reason of improved film adhesion, the tilt angle has to be changed in
situ . In principle, this can be done using sophisticated mechanical
devices that require additional vacuum feed-throughs. The system
described here allows in-situ adjustment of two inclination angles
using just one axle/feed-through by simply changing the sense of
rotation. The rotation around both, the sample holder axis and the
evaporated material beam axis, is maintained by this construction.

      As illustrated in the figure all the...