semi合集-English.pdf - 第6601页
SEMI C1-0705 © SEMI 1978, 2005 27 NOTICE: SEMI makes no warranties or represen tations as to the suitability o f the standards set forth herein for any particular application. The determination of the suitability of the …
SEMI C1-0705 © SEMI 1978, 2005 26
7.14.9.2 The smallest particle counter threshold should deliver at least 50% particle counting efficiency at the
control size limit. The control size limit is the particle size agreed upon between supplier and customer that
represents an acceptable size level. In general this size will be between 0.1 and 0.5 m.
7.14.9.3 Attach the cap with the gas inlet filter and sample tube to the reagent container to be sampled. Place the
reagent container in the canister, and seal the canister so that it may be pressurized. With the sample flow control
valve open, gradually (< 3 bar/min) pressurize the sample to 3 bar for H
2
O
2
and NH
4
OH or as necessary to obtain
the required flow for other fluids. Allow at least 250 mL of the sample to pass through the sensor before counting.
7.14.9.4 For each sample, after 5 aliquots have been measured, perform a chi-squared test to determine if the data
are statistically valid. If the chi-squared test fails, examine the apparatus for defects, such as loose or cracked
fittings, repair as necessary, and repeat the counting of 5 aliquots. If the sample fails both the second and third chi-
squared tests, it is considered to be immeasurable and should be discarded. If a second sample gives similar results,
the apparatus, including the OPC, may be defective and should be checked with a well-characterized sample and
repaired if necessary.
7.14.10 Measurement
7.14.10.1 Discrete Sampling — Measure multiple aliquots of the same sample. The flow rate must be the same as
that at which the instrument was calibrated. The statistical significance of any count data must be taken into
consideration. Some OPCs inspect as little as 1/1000
th
of the available sample flow, and may require a greater
number of aliquots and larger sampling volume to ensure good statistics. For example, to obtain a coefficient of
variation (standard deviation/mean) of 10%, it is necessary that at least 100 particles greater than the control size
limit be counted.
7.14.10.2 Continuous Sampling — If continuous sampling apparatus is being used, adjust the needle valve on the
rotameter to obtain a flow rate consistent with the instrument manufacturer’s recommendations. This flow rate must
be the same as that at which the instrument was calibrated. Correct the indicated value for the effect of the fluid
density and viscosity on the rotameter reading. Allow the first minutes’ fluid to flow to drain, then count the
particles in each of five, 15 second intervals. The statistical significance of any count data must be taken into
consideration. Some OPCs inspect as little as 1/1000
th
of the available sample flow, and may require a greater
number of aliquots and larger sampling volume to ensure good statistics. For example, to obtain a coefficient of
variation (standard deviation/mean) of 10%, it is necessary that at least 100 particles greater than the control size
limit be counted.
7.14.11 Shutdown — As in all portions of this procedure, appropriate safe liquid chemical handling practices must
be used. In particular, attention should be paid to the reactions between different reagents and between reagents and
diluents, including water, and to the inherent hazards of these materials.
7.14.11.1 After the measurement has been completed, vent the pressure vessel to atmospheric pressure through an
appropriate scrubber or exhaust hood, then flush the vessel with nitrogen to remove residual reagent vapors.
7.14.11.2 Flush the OPC and sample system with water or an appropriate solvent to remove the remaining fluid.
7.14.12 Coincidence and Efficiency Corrections — The determination of coincidence and efficiency correction
factors for particle counters is not recommended. If an OPC’s maximum concentration is exceeded, a different OPC
should be selected, or the sample diluted. However any sample dilution will impose additional error and is not
recommended.
7.14.13 Index of Refraction Correction — The determination of an index of refraction correction factor for particle
counters is not recommended, as the refractive index of the contaminating particle is unknown.
SEMI C1-0705 © SEMI 1978, 2005 27
NOTICE: SEMI makes no warranties or representations as to the suitability of the standards set forth herein for any
particular application. The determination of the suitability of the standard is solely the responsibility of the user.
Users are cautioned to refer to manufacturer's instructions, product labels, product data sheets, and other relevant
literature, respecting any materials or equipment mentioned herein. These standards are subject to change without
notice.
By publication of this standard, Semiconductor Equipment and Materials International (SEMI) takes no position
respecting the validity of any patent rights or copyrights asserted in connection with any items mentioned in this
standard. Users of this standard are expressly advised that determination of any such patent rights or copyrights, and
the risk of infringement of such rights are entirely their own responsibility.
Copyright by SEMI® (Semiconductor Equipment and Materials
International), 3081 Zanker Road, San Jose, CA 95134. Reproduction of
the contents in whole or in part is forbidden without express written
consent of SEMI.
SEMI C2-95 © SEMI 1981, 19961
SEMI C2-95
SPECIFICATIONS FOR ETCHANTS
1 Preface
1.1 The SEMI Committee on Chem ical Reagents
began its efforts on etchants in 1979. With this
publication, the Committee establishes definitions for
three major types of etchant mixtures; mixed acid
etchants, buffer oxide etchants, and phosphoric
etchants. Specifications and analytical procedures are
introduced for each type.
1.2 Etchants within all of the requirements can be
described as “meeting SEMI specifications.”
1.3 Where an analytical procedure different from that
provided is substituted by a supplier or user, the burden
of proof is on said supplier or user to confirm the
equivalency.
2 Definitions
2.1 All definitions set forth in SEM I C1, Section 2 are
adopted for SEMI C2.
2.2 Etchant — The exact definitio n of an etchant
mixture shall be set forth as the initial paragraph of its
Standard. The composition shall be expressed as a ratio
of the relative volumes taken of the components in an
assigned order. In the expression, all the relative
volumes shall be reduced to a ratio of the smallest
whole numbers. If a component is absent, its relative
volume shall be taken as zero.
2.3 Composition — The content o f each component of
an etchant shall be expressed on a weight/weight basis
of the 100% component (for example, 100% HF, not
49% HF). Any tolerance allowed for the content of a
component shall be expressed on a weight/weight basis
of that 100% component.
3 General Procedures and G uidelines to
Certain Methods
3.1 The general procedures and guidelines for certain
methods set forth in SEMI C1, Section 3 are adopted
for SEMI C2.
3.2 Determination of Nitric Acid b y Ultraviolet
Absorption Spectrophotometry
3.2.1 Introduction — The photometric determination
of nitric acid in various etchant mixtures is based on the
strong absorption of the nitrate ion in the ultraviolet
region. For this spectral region fused silica (quartz)
cells are required.
3.2.2 Preparation of Calibration Curve — Secure a
bottle of nitric acid (70%) and determine its assay in
duplicate. Accurately weigh 2.8 to 3.0 g dilute with 100
mL of water, add 10 drops of phenolphthalein indicator
solution to each solution, and titrate with standardized 1
N sodium hydroxide solution to a pink end-point.
(g) Sample ofWeight
6.302NaOH of mL
)( Acid Nitric %
w
w
××
=
N
If the results do not differ by more than 0.2%, average
them. Otherwise, repeat the analysis.
3.2.3 In five previously tared weigh ing bottles,
accurately weigh about 1.0, 1.2, 1.4, 1.6 and 1.8 g of
the previously assayed 70% nitric acid. Calculate the
weight, in grams, of 100% nitric acid present in each of
these five standards. Quantitatively transfer each
standard to a separate 100 mL volumetric flask, dilute
to volume with water, and mix thoroughly.
3.2.4 Following the manufacturer’s directions, ready a
spectrophotometer and set the wavelength to 302 nm.
Measure the absorbance of each standard versus water
using a 1 cm fused silica cell. On (linear) coordinate
graph paper plot the absorbance versus the weight, in
grams, of 100% nitric acid for each standard. Draw the
best-fitting straight line through the points.
3.2.5 Application to Acid Etch Mixtu res — Proceed as
given under the Standard for the relevant etchant.
4 Reagent and Standard So lutions
4.1 The reagent and standard solutions set forth in
SEMI C1, Section 4 are adopted for SEMI C2.
4.2 Acetate Buffer for Hydrofluoric Acid
Determination — Dissolve 106 g of sodium acetate
trihydrate, CH
3
COONa•3H
2
O, and 137 g of ammonium
acetate, CH
3
COOHN
4
, in about 700 mL of water. Add
5.1 mL of glacial acetic acid, adjust to pH 5.5-6.6 with
dilute ammonium hydroxide (10% NH
3
) or dilute acetic
acid (20%), and dilute to 1000 mL with water.
4.3 Aluminum Chloride Standard Solution
Preparation — Dissolve 40.0 g of aluminum chloride
hexahydrate, AlCl
3
•6H
2
O, in about 700 mL of water
and 0.5 mL of hydrochloric acid contained in a 1000
mL volumetric flask; dilute to volume with water, and
mix thoroughly.
4.3.1 Standardization — Transfer 1.5 mL of hydro-
fluoric acid to a 250 mL polyethylene beaker containing
50 mL of water. Add 10 drops of phenolphthalein
indicator solution. With magnetic stirring, titrate with
standarized 1N sodium hydroxide solution to a pink