semi合集-English.pdf - 第6595页
SEMI C1-0705 © SEMI 1978, 2005 21 Element Symbol Line (nm) Boron (B) 249.77 Cadmium (Cd) 214.44 Calcium (Ca) 393.27 Chromium (Cr) 205.55 Copper (Cu) 324.75 Iron (Fe) 238.20 Lead (Pb) 220.35 Lithium (Li) 670.78 Magnesium …
SEMI C1-0705 © SEMI 1978, 2005 20
7.11.1 Equipment — The source is a hollow cathode lamp, or equivalent, for the relevant element. The furnace will
contain a pyrolytic coated graphite tube that has been conditioned according to manufacturer’s instructions. The
monochromator should have a resolution of at least 0.1 nm. The signal from the photomultiplier tube detector is
read from a meter, digital display, or recorder tracing. Zeeman or deuterium background correction can be used. An
autosampler is suggested in order to obtain better reproducibility.
7.11.2 Operating Conditions — Use an acceptable flow rate (300 mL per minute) argon as the inert carrier gas,
with no flow during the atomization portion of the program. The temperature programs outlined by the instrument
manufacturers should be checked using known standards, and adapted as necessary for optimum performance for a
specific instrument. Calibrate the temperature controller for the different atomization temperatures used for each
element. The conditions for iron, potassium, calcium, and sodium are included in Table 9.
Table 9 Conditions for Graphite Furnace Atomic Absorption Spectrometry
Element Iron Potassium Calcium Sodium
Wavelength (nm) 248.3 766.5 422.7 589.1
Bandwidth (nm) 0.2 1.4 2.0 0.2
Current (mA) 30 6 8 8
L’vov Platform Yes Yes Optional Yes
Sample Size (µL) 20 10 10 10
7.11.3 Solutions Conditions — The solutions are prepared as given in the procedures for the individual liquid
chemical. All solutions will be prepared in a clean environment as defined in the SEMI guidelines.
7.11.4 Working Standard Solutions — Working standard solutions should be prepared on the day of use by dilution
of a stock standard solution.
7.11.5 Sample Preparations — Sample preparation will be analyzed neat, with pre-concentration, or by dilution,
according to the individual procedure.
7.11.6 Quantification — Results shall be reported as the result of three replicate analyses. Each replicate is the
result of an 8-second integration of the peak area with the instrument in concentration mode. Recording should
commence 5 seconds before the atomization, and baseline should be established 2 seconds prior to atomization.
Reading should commence 1 second prior to atomization. Alternate integration schemes for the analytical peak shall
be performed in a manner that captures all of the signal, as appropriate for the instrument.
7.11.7 Calibration — Calibrate the instrument using a standard prepared in the appropriate grade of 18.2 Mohm-cm
water that meets ASTM Standard Guide D5127, over a concentration range appropriate for the analysis. The blank
must also be contained in the appropriate grade of 18.2 Mohm-cm water that meets ASTM Standard Guide D5127.
7.12 Determination of Trace Elements by Inductively Coupled Plasma Optical Emission Spectrometry
(ICP-OES) — The purpose here is to describe in general terms how the technique should be used when specified in
the procedures for an individual liquid chemical to assure that the specifications for one or more stated elements are
met. No general procedure is given since operating details will vary with instrument design; consequently, the
manufacturer’s manual should be followed.
7.12.1 Equipment — A spectrometer with sufficient resolution to separate the typical spectral lines of the elements
stated in the specification for an individual liquid chemical. The signal from the detector is processed by a computer
system and displayed on a recorder with graphics capability. A background correction technique is required.
Typical emission lines are listed in Table 10.
Table 10 Suggested Plasma Emission Line
Element Symbol Line (nm)
Aluminum (Al) 396.15
Antimony (Sb) 206.83
Arsenic (As) 193.76
Barium (Ba) 455.40
SEMI C1-0705 © SEMI 1978, 2005 21
Element Symbol Line (nm)
Boron (B) 249.77
Cadmium (Cd) 214.44
Calcium (Ca) 393.27
Chromium (Cr) 205.55
Copper (Cu) 324.75
Iron (Fe) 238.20
Lead (Pb) 220.35
Lithium (Li) 670.78
Magnesium (Mg) 279.55
Manganese (Mn) 257.60
Nickel (Ni) 231.6
Potassium (K) 766.49
Sodium (Na) 589.59
Tin (Sn) 189.99
Titanium (Ti) 334.94
Vanadium (V) 292.40
Zinc (Zn) 213.86
7.12.2 Operating Conditions — Sensitivity, instrumental detection limit, precision, linear dynamic range, and
interference effects must be investigated and established for each individual analyte line on that particular
instrument. Types of interferences other than the simple overlap of a concomitant line on an analyte line must be
considered.
7.12.3 Solution Conditions — The solutions are prepared as given in the procedures for the individual liquid
chemical.
7.12.4 Working Standard Solutions — Working standard solutions should be prepared on the day of use by dilution
of a stock standard solution. For best results, standards should be matrix matched.
7.12.5 Multi-element standards may be prepared. The components should be selected to provide stable standards
within the required concentration range.
7.12.6 Quantitation — Commonly, the samples are measured against matrix-matched calibration standards;
however, whenever a new or unusual matrix is encountered, the method of standard addition is employed. The
standard addition does not detect coincident spectral overlap; an alternate wavelength or an alternate method is
recommended for verification. A calibration obtained with aqueous standards may be used if its slope and the
standard addition method slope are identical.
7.12.7 Evaporation of Sample — The detection limits achievable can be improved by preconcentration of a large
sample by evaporation. Through volatilization there may be a loss of trace elements, and recovery study data must
be obtained. The loss of trace elements in this enrichment process can be reduced, often by the presence of
additives. The evaporation must be conducted under “clean air” conditions, and reliability should be assured by use
of a “blank” or control sample determination. The sample size will depend on the detection limits required and the
capability of the instrument used.
7.12.8 Background Correction — A background correction technique is required for variable background
contribution to the determination of trace elements. The correction interval should be selected such that the intensity
of the background at that wavelength is equal to the background intensity under the analyte peak.
7.12.9 Additives — The procedures for the individual liquid chemical will provide detailed instructions for required
additives in the sample solution.
7.12.10 Remarks — The manufacturer’s manual should be consulted for proper use of the instrument. The user
should check the performance of the instrument from time to time to assure that adequate sensitivity is being
attained for the needs of the particular determination.
SEMI C1-0705 © SEMI 1978, 2005 22
7.13 Determination of Trace Elements by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) — The
determination of trace elements in liquid chemicals which are commonly used in advanced semi-conductor
manufacturing requires a sensitive technique with the ability to perform simultaneous analysis for multiple elements.
Achievable detection limits are adequate for sample analysis with little sample preparation prior to analysis. Liquid
chemical matrix reduction needed to perform routine analysis is often achieved by dilution of the sample. Water
used for dilution should be the appropriate grade of 18.2 Mohm-cm water that meets ASTM Standard Guide D5127.
Matrix removal methods which require sample evaporation should be performed under HEPA filtered air such that
reproducible blank samples are obtained at or less than one half the specified limit of trace elements for the sample.
No specific procedure for inductively coupled plasma mass spectrometry is included since instrumentation and
practices vary among laboratories. Some practical considerations relevant to the method are outlined below.
7.13.1 Equipment — A mass spectrometer with better than 1 amu resolution from 5–250 amu is required to separate
the isotopes of the elements stated in the specification for an individual liquid chemical. The use of hot or cool
plasmas as well as a collision/reaction cell may be required to meet the SEMI detection limit requirements for
certain analytes. The signal from the detector is digitized by a computer system for quantitative calculation.
Interference correction may be required for some isotopes. Typical analytically useful masses are listed in Table 11.
Table 11 Suggested Analytical Masses
Element Masses
Aluminum (Al) 27
Antimony (Sb) 121, 123
Arsenic (As) 75
Barium (Ba) 137, 138
Boron (B) 11
Cadmium (Cd) 111, 114
Calcium (Ca) 40
Chromium (Cr) 52
Copper (Cu) 63, 65
Iron (Fe) 56
Lead (Pb) 206, 207, 208
Lithium (Li) 7
Magnesium (Mg) 24
Manganese (Mn) 55
Nickel (Ni) 58, 60
Potassium (K) 39
Sodium (Na) 23
Tin (Sn) 118, 120
Titanium (Ti) 48
Vanadium (V) 51
Zinc (Zn) 64, 66
7.13.2 Sample Introduction — Conventional glassware used for sample introduction is in most cases appropriate for
liquid chemical analysis, however for Grade 5 liquid chemicals an ultra clean sample introduction system is
recommended. Liquid chemicals containing hydrofluoric acid (HF) require a HF resistant introduction system
unless the hydrofluoric acid matrix is removed prior to the analysis.
7.13.3 Ionization Source — An inductively coupled plasma using argon as the support gas has proven to be
satisfactory as an ionization source for the method. Ionization conditions present in the argon plasma are highly
dependent on the various argon gas flow rates used to support the plasma. Sample introduction techniques used to
introduce the sample into the plasma are important to the analysis of the samples and must be optimized to allow
successful analysis. In particular, sample uptake and nebulizer gas flow require special attention and should be
treated carefully in order to optimize instrument performance for each of the various liquid chemicals.