Formation of large particles on substrate is eliminated by actively exhausting reacted gases. Effluent gas backflow is prevented by pumping in curtain of nitrogen above fresh reactive gases from several directions

Chern, S. S.

Maserjian, J.

English

NASA Technical Reports Server

September 1975	 B75-10212 
NASA TECH BRIEF
A 
NASA Pasadena Office  
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. . Requests for individual copies or questions relating to the Tech Brief program . may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Improved Chemical Vapor-Deposition Reactor 
The problem: 
Chemical vapor deposition is used in depositing 
thin dielectric films on microelectronic components 
during fabrication. Two basic problems occur during 
this process. Often the deposited films include large 
particles in an otherwise finely grained structure. 
These particles are deposited when the reacted gases 
are eliminated too slowly by free convection, forming 
large particles that "snow" onto the substrate. In 
addition, the films are frequently nonuniform in 
thickness because of the uneven distribution of 
incoming reactive gas due to free convection.
The solution: 
High-quality thin films can be obtained using a 
modified vapor-deposition reactor. 
How it's done: 
The new reactor includes modifications as shown in 
the illustration. The problem due to free convection is 
eliminated by actively exhausting the reacted gases. A 
chimney is used to exhaust the gases directly into the 
atmosphere or to a vacuum. This prevents the 
formation of a large particles on the substrate. 
Chimney Exhaust 
to Atmosphere or 
to Vacuum 
BafflE
N2 
\	 High-Velocity 
Reactive Gases 
Hntnlf	 (SiN4 and 0 In N2) 
N2
High-Velocity
Reactive Gases
(S1H 4 and 02 in N2)
}Reactive Gases 
N2
Modified Vapor Deposition Reactor 
• 
(continued overleaf) 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United Slates	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United Slates 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19750000212 2020-03-19T20:26:41+00:00Z
Effluent gas backflow is prevented by pumping in a 
curtain of nitrogen above the fresh reactive gases from 
several directions. 
As shown in the illustration, fresh reactive gases are 
introduced from two diametrically opposite directions 
with sufficient velocity to flow to the opposite sides of 
the substrate. These fresh gases replace the compo-
nents of the reacted gas which have not been extracted 
in the formation of the film. The even distribution of 
these gases produces a uniform film thickness. 
Several other gas-inlet configurations have been 
developed for the uniform distribution of the reactive 
gases. These are even more effective and are described 
in detail in a report.
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP75-10212 
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
Patent Counsel 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Source: Shy-Shiun Chern and. 
Joseph Maserjian of 
Caltech/JPL 
• •	 (NPO-13650) 
Categories: 08 (Fabrication Technology) 
04 (Materials) 
01 (Electronics - Components 
B75-10212	 and Circuitry)


Improved chemical vapor-deposition reactor

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server