ASTM F804-83(1990)E01

Practice for Producing Spin Coating Resist Thickness Curves (Withdrawn 1997)

General Information

• Status: Withdrawn
• Withdrawal Date: 09-Dec-1997
• Technical Committee: F01 - Electronics

Standards Content (Sample)

ASTM FBO'i*EL 83 - 0759530 0081659 0 m
Designation: F 804 - 83 (Reapproved 1990)”
tlSTb
Standard Practice for
Producing Spin Coating Resist Thickness Curves’
This standard is issued under the fixed designation F 804: the number immediately following 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
superscript epsilon (c) indicates an editorial change since the last revision or reapproval.
cr NOTE-Test Method F 907 added to Referenced Document section editoriallv in Julv 1991.
performance of a spin coater to determine its reliability and
1. Scope
repeatability.
1.1 This practice covers the procedure for producing spin
4.3 The coating characteristics for various resists can be
coating thickness curves for radiation-sensitive resists on
evaluated and compared.
wafers, substrates, and mask blanks.
NOTE l--Several types of thickness-measuring techniques and equip-
5. Terminology
ment are available for use in this practice.
5.1 Definitions:
1.2 This practice is applicable for resist coating thick-
5.1.1 Terms used in this practice are found in Definitions
nesses from submicrometre to several micrometres.
F 127.
5.2 Descriptions of Terms SpeciJic to This Standard:
2. Referenced Documents
5.2.1 resist-a radiation-sensitive material used to mask
2.1 ASTM Standards: portions of a substrate surface in an imaging process that
F 127 Definitions of Terms Relating to Photomasking includes exposure of the material to patterned radiation of
electromagnetic waves such as visible, ultraviolet, or X rays
Technology for Microelectronics*
or of particles such as electron beams.
F 907 Test Method for Measurement of Rotational Accel-
5.2.2 spin coater-apparatus or equipment by which resist
eration of a Wafer for Photoresist Spin Coating*
is applied to the surface of a rotating substrate.
2.2 Other Standards:
Fed. Std. No. 209B Clean Room and Work Station Re-
6. Interferences
quirements, Controlled Environment3
Code of Federal Regulations, Title 29, Part 19 10, Occupa-
6.1 Spin coaters vary in respect to specific coating charac-
tional Safety and Health Standards4
teristics. The spin coating recommendations supplied by
resist producers provide a basic guide for user application.
3. Summary of Practice
6.2 Drying and baking conditions of time and tempera-
3.1 A specific resist thickness is applied to the surface of a
ture will affect the measured resist thickness through removal
. .
substrate by spin coating. The thickness after drying depends
of the carrier solvent and densification of the layer for all
on the coating equipment parameters and characteristics of
types of measuring instruments.
the substrate and resist. The resulting thickness of the dried
6.3 In noncontact measurement techniques, changes in
resist layer is measured. A correlation between measured
the optical parameters of the resist layer may result from the
thicknesses and a set of spin coating speeds produces a spin
baking conditions used in drying the resist.
coating curve for future applications.
6.4 In noncontact measurement techniques, exposure of
the resist layer to its radiation-sensitive wavelengths may
4. Significance and Use
affect the optical parameters of the layer.
6.5 In noncontact measurement techniques, the optical
4.1 The delineation of the line geometric patterns on
parameters (reflectivity, absorptivity, and refractive index) of
photomask substrates and semiconductor wafers depends on
any specimen surface layers underlying the resist will influ-
the uniformity and repeatability of resist coating thickness. A
ence the measurements in this practice. _ .
standard practice, as described here, is essential for process
6.6 In contact thickness measurement techniques; chemi-
control during the fabrication steps in microelectronics
caliy produced steps in the resist layer are generally unsatis-
device manufacture.
factory for profde measurement in this practice. .
4.2 This -practice provides a means for verifying the
6.6.1. Resist removal by chemical scribing or wiping may
produce’distorted and tapered step edges which degrade the.
r This practiceis under the jurisdiction of ASTM Corn&tee F-l on Electronics accuracy of measurement.
and is, the direct responsibility of Subcommittee FOl.08 on Microelectronic
6.6.2 Resist exposure and image development to produce
.t
Imaging. -.
steps ‘in the layer may change the original coated thickness
Current edition approved March 25, 1983. Published May 1983. L .: i,
s-.
_
basis for measurement. ‘.
-.2 Ayual Book o/ASTM Slandards, Vol 10.05. .
3 Available from Standardization Documents Order Desk, Bldg. 4 Section D,
__
NOTE 2-Measurement of the resist thickness utilizing exposed and-
700 Robbins Ave., Philadelphia, PA I9 I I l-5094; Attn: NPODS.
developed images (thickness after development) is, however, a useful
4 Available from Occupational Safety and Health Review Commission, 1825 K:
Street, N.W., Washington, D.C. 20006. determination for lithographic process evaluations when used in con-
. .
‘ASTM FB04*El, 63 W 0759530 OiJBLbbO 7 m
junction with the original coating thickness determination obtained in
9.2 Handle the materials in a well ventilated area away
this practice.
from flames, hot surfaces, sparks, and other sources of
ignition since the resist and associated solvents may be
7. Apparatus
flammable and toxic. -
7.1 Spin Coater, having controlled acceleration to given
9.3 Wear safety glasses for eye protection during all
spinning speeds in the nominal range 500 to 8 000 rpm and
operations.
capable of maintaining those speeds for controlled times.
The spin coater should be of the type customarily used for
10. Sampling, Test Specimens, and Test Units
coating resist.
10.1 This practice is for use in determination of the
NOTE 3-Test Method F907 can be used to characterize the spin
coating thickness characteristics of a single representative
coater acceleration and speed parameters which are used- in the
sample of resist, The selection of test specimens of substrates
application of this practice.
upon which thickness results are determined is subject to
7.2 Resist Dispenser, with or without fdteringat point-
agreement between the parties to the test.
of-use.
10.2 The test specimen is a single substrate upon which
7.3 Drying Oven, for baking the coated substrates after
resist coating thickness measurements are determined. The
spin coating. The oven should be capable of maintaining a
type of substrate and the number and location of thickness
selected temperature within SC over the range 70 to
determinations on each specimen are subject to agreement
2OO”C, inclusive.
between the parties to the test.
7.4 Thickness Measuring Instrument, of a type custom-
10.3 The test unit is the number of substrates that are
arily used for resist thickness measurement in the range 0.1
coated at a given set of coating parameters from which an
to 3.0 urn. The instrument may be noncontact as identified
average coating thickness result is determined for plotting on
in 7.4.1 or contact as described in 7.4.2.
the spin coating curve.
7.4.1 Noncontact types of thickness measuring instru-
NOTE I-The number of observations per substrate and specimens
ments utilize optical techniques of ellipsometry or interfe-
per unit will influence the applicability of the test results. The thickness
rometry.
uniformity of resist on a substrate may also be observed by comparing
7.4.2 Contacting types of instruments for resist thickness
th
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