Gold film is vapor deposited onto a glass slide containing submicron latex spheres which are removed, leaving submicron holes in the film. These thin-film apertures allow accurate mass spectrometer sampling of gas mixtures at pressures on the order of 100 torr

Willens, R. H.

English

NASA Technical Reports Server

Platini 
Suppo 
Piece
Gold Film 
August 1966	 Brief 66-10380 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Submicron Holes in Thin Films Increase Sampling Range

of Mass Spectrometers 
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The problem: 
To devise a process of forming thin-film apertures 
of less than 1 micron in diameter to allow accurate 
mass spectrometer sampling of gas mixtures at pres-
sures on the order of 100 torr. To ensure proper 
sampling, the aperture must not only have a diameter 
smaller than the mean free path of the gas molecules 
but also a channel length of only a few diameters. 
The solution: 
A process involving the vapor deposition of a gold 
film onto a glass slide containing submicron latex 
spheres which are then removed, leaving submicron 
holes in the gold film. 
How it's done: 
Evaporate a wetting agent to a thickness of several 
hundred angstroms onto a glass slide. Spray the 
coated surface with a dispersion of submicron latex 
spheres. Evaporate a gold film, 500 to 1000 angstroms 
thick, onto the surface, so that the latex spheres leave
"shadow holes" in the gold film. Remove the latex 
spheres, using an air stream and a wash in benzene 
and acetone. Cut the remaining gold foil into small 
squares and strip them from the glass slide onto a 
water surface. Lift a gold square from the water sur-
face by means of a hollow, cylindrical platinum sup-
port piece, and position the square so that the sub-
micron hole is approximately centered over the hole 
in the support piece. Fusion bond the gold square to 
the support piece. 
To prevent plugging of the submicron hole by parti-
cles that may be carried in the gas stream, it is neces-
sary to provide a filter. The filter is constructed using 
the same procedure described above, except that a dis-
persion of smaller latex spheres is used so that a 
larger number of holes is obtained in the gold film. 
A specially designed fixture is used to mount the thin 
film assembly in an opening through a wall of the 
spectrometer housing.
(continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000379 2020-03-11T17:40:40+00:00Z
Note: 
Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: B66-10380
Patent status: 
No patent action is contemplated by NASA. 
Source: R. H. Willens 
of Consolidated Systems, Inc. 
under contract to 
Jet Propulsion Laboratory 
(JPL-SC-097) 
Brief 66-10380	 Category 03


Submicron holes in thin films increase sampling range of mass spectrometers

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