Oxide film thickness standards and manufacturing methods...

Details Oxide film thickness standards and manufacturing methods... Oxide film thickness standards and manufacturing methods...

1999-09-30

2001-05-15

Meeks, Timothy (Department: 1762)

Coating processes

Electrical product produced

Integrated circuit, printed circuit, or circuit board

C427S579000, C427S255700, C438S014000, C073S001010, C073S001810

Reexamination Certificate

active

06231918

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to microelectronic devices and manufacturing methods, and more particularly to film thickness standards and manufacturing methods thereof
BACKGROUND OF THE INVENTION
Generally, integrated circuit devices are manufactured in such a manner that various kinds of films are formed on the semiconductor substrates. The various kinds of films are formed to have certain ranges of thickness. Accordingly, a film thickness standard (FTS) reference material measuring film thickness is provided and used to control the thickness of the various kinds of films.
The conventional oxide film thickness standard reference has a thickness less than 1 &mgr;m. The oxide film thickness standard reference having a thickness of less than 1 &mgr;m is described in detail in the catalogue of VLSI Standards Incorporated 1996 Product Guide.
However, the above oxide film standard thickness reference having a thickness below 1 &mgr;m may not be sufficient to calibrate state of the art thin film manufacturing including an oxide film over 1 &mgr;m thick.
Unfortunately, it may be difficult to fabricate oxide film thickness standards having a thickness over 1 &mgr;m without defects such as uniformity variations. Thus, it generally is difficult to set up process conditions to prepare the oxide film thickness standard reference having a thickness over 1 &mgr;m.
SUMMARY OF THE INVENTION
The present invention provides a film thickness standard (FTS) that can be used to calibrate the thickness of an oxide film having a thickness over 1 &mgr;m. The film thickness standard comprises an oxide film having a thickness over 1 &mgr;m on a semiconductor substrate.
The semiconductor substrate is preferably a silicon substrate. Preferably, the oxide film is a plasma enhanced oxide film or Tetra-Ethyl-Orthosilicate oxide film.
The thickness value designated as the thickness of said oxide film has continuity in thickness, and preferably, the continuous thickness is a linear function on plane coordinates. The oxide film is formed having a thickness of 1.1 &mgr;m to 1.3 &mgr;m, 2.3 &mgr;m to 2.5 &mgr;m, 3.2 &mgr;m to 3.4 &mgr;m, 4.3 &mgr;m to 4.5 &mgr;m and 5.1 &mgr;m to 5.3 &mgr;m, etc., and preferably, is formed having a thickness of 1.2 &mgr;m, 2.4 &mgr;m, 3.3 &mgr;m, 4.4 &mgr;m and 5.2 &mgr;m, etc. The uniformity of the oxide film is maintained within a deviation of 0.3% for the entire thickness of the oxide film
12
.
A method of preparing a film thickness standard comprises the step of repeatedly forming an oxide film under the same processing conditions thereby to form the film thickness standard on a semiconductor substrate having thickness greater than a predetermined level. Preferably, the thickness of the oxide film is over 1 &mgr;m, is continuous in thickness and is designated as a linear function on plane coordinates.
Preferably, the oxide film is formed by performing Plasma Enhanced Oxidation process, and setting up its thickness as 4,000 Å. The Plasma Enhanced Oxidation process is performed by supplying 95 liter/min. of SiH
4
and 1800 liter/min. of N
2
O gas, and preferably, at temperature of 400° C. and at pressure of 2.9 Torr.
A method of preparing a film thickness standard comprises the steps of: a) performing a test for characteristics of oxide films formed by various kinds of methods; b) deciding the process conditions for the formation of the oxide films as the thickness standard reference by the test results; c) setting the standard value of the thickness of the oxide film for the process conditions for the formation of the oxide films; d) forming the oxide films by the set standard value; and e) analyzing the characteristics of the oxide film so formed.


REFERENCES:
patent: 4355903 (1982-10-01), Sandercock
patent: 5356722 (1994-10-01), Nguyen et al.
patent: 5486701 (1996-01-01), North et al.
patent: 5535359 (1996-07-01), Bartha et al.
patent: 5578745 (1996-11-01), Bayer et al.
patent: 5686993 (1997-11-01), Kokubo et al.
patent: 5851602 (1998-12-01), Law et al.
Candela et al., SPIE vol. 661, Optical Testing and Metrology, pp 402-407, 1986 (no month).*
VLSI Standards Incorporated, 1996 Product Guide (No month).

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