ASTM F388-84

Method for Measurement of Oxide Thickness on Silicon Wafers and Metallization Thickness by Multiple-Beam Interference (Tolansky Method) (Withdrawn 1993)

General Information

• Status: Withdrawn
• Withdrawal Date: 14-Aug-1993
• ICS: 29.045 - Semiconducting materials
• Technical Committee: F01 - Electronics

Standards Content (Sample)

Designation: F 388 - 84
4clti
AMERICAN SOCIETY FOR TESTING AND MATERIALS
1916 Race St., Philadelphia, Pa. 49103
Reprinted from the Annual Book of ASTM Standards, Copyright ASTM
If not listed in the current combined index, will appear in the next edition.
Standard Method for
MEASUREMENT OF OXIDE THICKNESS ON SILICON
WAFERS AND METALLIZATION THICKNESS BY MULTIPLE-
BEAM INTERFERENCE (TOLANSKY METHOD)'
This standard is issued under the fixed designation F 388; the number immediately foliowing the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A supencripf epsilon (6) indicatesan editorial change since the last revision or reapproval.
1. Scope ing. This step and the adjacent plane areas are
coated with a reflective metal (usually aluminum
1.1 This destructive method covers the mea-
or silver). A partly reflecting flat glass plate is
surement of the thickness of a uniform layer
placed over the metallized area which is illumi-
formed on or deposited upon a flat surface. The
nated by monochromatic light through the glass
method is appropriate for measurements of lay-
plate. The plate is tilted slightly to produce an
ers from 4 to 3000 nm thick.
interference pattern of parallel lines. The direc-
1.2 The referee procedure is suitable for re-
tion of the tilt is adjusted to make these lines
search laboratories and in process control appli-
perpendicular to the step. A photograph of the
cations where increased precision is required or
interference pattern is made. The parallel inter-
to calibrate other thickness measurement meth-
ference lines are displaced at the step by an off-
ods. Two nonreferee procedures suitable for gen-
set distance proportional to the step thickness.
eral use are also given.
This off-set distance and the spacing between
1.3 This standard may involve hazardous ma-
adjacent parallel lines are measured. Since the
teriak operations, and equipment. This standard
spacing between successive parallel lines in the
does not purport to address all of the safetyprob-
plane areas corresponds to a half wavelength of
lems associated with its use. It is the responsibil-
the monochromatic light, the thickness of the
iíy of whoever uses this standard to consult and
layer is the off-set distance multiplied by the half
establish appropriate sajêty and health practices
wavelength of the light divided by the spacing
of regulatory limi-*
and determine the applicability
between interference lines.
tations prior to use. Specific precautionary state-
ments are given in Section 8.
4. Significance and Use
2. Applicable Documents
4.1 Thin silicon dioxide films are used in sem-
iconductor device fabrication for isolation, for
2.1 ASTM Standard:
protection of surfaces (passivation), and for
D 1 125 Test Methods for Electrical Conductiv-
ity and Resistivity of Wate8
2.2 SEMI Standards:
' This method is under the jurisdiction of ASTM Committee
F-I on Electronics and is the direct responsibility of Subcom-
CI Specifications for Reagend
FO1.06 on Eleclrical and Optical Measurements
mittee
2.3 Other Standard:
Current edition approved Jan. 27, 1984. Published April
1984.OriginallypublishedasF388-73T. Lastpreviousedition
Reagent Chemicals, American Chemical So-
F388 - 17 (1982).
ciety Specifications4
'Annual Book ofASTMSiandar&, Vol 11.01.
'Available from the Semiconductor Equipment and Ma&
3. Summary of Method
rials Institute, 625 Ellis St., Suite 212, Mountain View, CA
94043.
3.1 A step in the layer whose thickness is to
'Available from American Chemical Society, Washington,
be measured is produced by etching or shadow- Dc 20036.

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ASTM F388 84 0759530 005348b T W
F 388
rounded to 546.0 nm for the green line and for
masking in diffusion processes. A. precise mea-
surement of oxide thickness is not only necessary the thallium light source when 535.046 nm is
to provide optimum device yield and reliability, rounded to 535.0 nm.'
but also it is useful as a process control parame-
6. Apparatus
ter.
4.2 The control of metallization thickness is
6. I MetaIlurgicaI Microscope, with camera
required in semiconductor device fabrication in
and provisions for vertical illumination from an
order to ensure optimum reliability and electrical
external source. Magnification should be sufi-
conductivity within the design tolerance.
ciently adjustable to ensure that six interference
4.3 No interlaboratory precision has been es-
fringes (see 12.1.3) should fill at least 50 mm of
tablished for this technique. It is not recom-
the photograph. Magnification of lox to 100~
mended that this method be used for the accept-
should be satisfactory for the usual specimens.
ance or rejection of material exchanged between
Photographs of a nominal 2.75 by 3.75-in. (70
suppliers an
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