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SEMI E46-0301 © SEMI 1995 , 2001 1 SEMI E46-0301 TEST METHOD FOR THE DETERMINATION OF ORGANIC CONTAMIN A TI ON FROM M INIENVIRONMENTS USING ION MOBI LITY SPECTROMETRY (IMS) This test method was tec hnically approved by t…

SEMI E45-1101 © SEMI 1995, 20015

8.9.1 Minienvironment Exposure — The following

exposure time for sampling specific minienvironments

shall be used:

Minienvironments used to store wafers: 168 h

Minienvironments as an interface to process tools:

24 h

8.9.2 Minienvironments for Storing Wafers — Fill the

minienvironment with six wafers. Measure wafers by

VPD/GFAAS or VPD/ICP-MS in front, back, and

center slots. Use the adjacent wafers for VPD/TXRF.

8.9.3 Minienvironments for Introducing Wafers to

Process Tools — Introduce six wafers into the

minienvironment. Measure three wafers with

VPD/GFAAS or VPD/ICP-MS, one in the center

position and two at the edge positions opposite to each

other. Use the adjacent wafers for VPD/TXRF. In the

case of single wafer minienvironments, wafers are

processed sequentially. To ensure that no cross

contamination is introduced from conditions prevailing

in storing, transportation, or any of the handling

processes, precautions must be adhered to at all times.

9 Results

9.1 The investigated minienvironment must be

described in detail (e.g., construction, materials, history,

process, cleaning procedures, storage conditions). All

surface concentrations must be fully reported.

9.2 The number of tested sampling and reference

wafers, average elemental concentration, and standard

deviation of the reference wafers, slot positions,

position in the minienvironment, and number of

repeated experiments (if applicable) must be

documented.

9.3 All equipment, tools, and chemicals used must be

specified within the report.

10 Related Documents

10.1 SEMI Standards

SEMI C30 — Specifications and Guidelines for

Hydrogen Peroxide

NOTE 2: Unless otherwise indicated, all documents cited

shall be the latest published versions.

10.2 Other Documents

A. Shimazaki, H. Hiratsuka, Y. Matsushita, S. Yoshii,

Ext. Abs. 16th Conference on Solid State Devices and

Materials, Kobe, 281 (1984).

M. Hourai, T. Nakidomi, Y. Oka, K. Murakami, S.

Sumita, N. Fujino, T. Shiraiwa, Japan Journal of

Applied Physics 27, 12 (1988) L2361.

A. Huber, H.J. Rath, P. Eichinger, T. Bauer, L. Kotz, R.

Staudigl, Diagnostic Techniques for Semiconductor

Materials and Devices, ed. by T.J. Shaffner, D.K.

Schroder, ECS Proc. Vol. 88-20, 109 (1988).

P. Eichinger, H.J. Rath, H. Schwenke, Semiconductor

Fabrication: Technology and Metrology, ASTM STP

990, ed. by D.C. Gupta, American Society for Testing

and Materials, 305 (1989).

C. Neumann, P. Eichinger, Spectrochim. Acta 46B,

1369 (1991).

A. Shimazaki, Defects in Silicon II, ed. by W.M. Bullis,

U. Gösele, and F. Shimura, ECS Proc. Vol. 91-9, 47

(1991).

W. Hub, V. Penka, Microcontamination Conference

Proceedings, San Jose, Oct. 1991, 266.

N. Streckfuss, L. Frey, G. Zielonka, F. Kroninger, C.

Ryzlewicz, H. Ryssel, Fresenius Journal Analytical

Chemistry 343, 765 (1992).

R.S. Hockett, S. Ikeda, T. Taniguchi, Cleaning

Technology in Semiconductor Device Manufacturing,

ed. by J. Ruzyllo, R.E. Novak, ECS Proc. Vol. 92-12,

324 (1992).

L. Fabry, S. Pahlke, L. Kotz, E. Schemmel, Crystalline

Defects and Contamination: Their Impact and Control

in Device Manufacturing, ed. by B.O. Kolbesen, C.

Claeys, P. Stallhofer, F. Tardif, ECS Proc. Vol. 93-15,

232 (1993).

S. Tan, Nuclear Instruments and Materials in Physics

Research B99, 458 (1995).

NOTICE: SEMI makes no warranties or representa-

tions 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.

The user’s attention is called to the possibility that

compliance with this standard may require use of

copyrighted material or of an invention covered by

patent rights. 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.

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consent of SEMI.

SEMI E46-0301 © SEMI 1995, 20011

SEMI E46-0301

TEST METHOD FOR THE DETERMINATION OF ORGANIC

CONTAMINATION FROM MINIENVIRONMENTS USING ION MOBILITY

SPECTROMETRY (IMS)

This test method was technically approved by the Global Metrics Committee and is the direct responsibility

of the European Equipment Automation Committee. Current edition approved by the European Regional

Standards Committee on December 20, 2000. Initially available at www.semi.org February 2001; to be

published March 2001. Originally published in 1995.

1 Purpose

1.1 The purpose of this test method is to provide an

analytical procedure—Ion Mobility Spectrometry

(IMS)—for the determination of organic contamination

from minienvironments which has the capability of

testing their construction material.

2 Scope

2.1 Silicon wafers passed through or stored in

minienvironments may be affected by organic

contamination originating from construction materials.

Knowledge of this contamination assists the decision

about the application of minienvironments in

semiconductor manufacturing.

2.2 Ion Mobility Spectrometry was chosen as the

method to determine this contamination because it

provides an easy, widely applicable, fast and sensitive

way to measure organic contamination on surfaces.

2.3 Furthermore, IMS provides the possibility of

checking the contaminating effects of processing,

chemical carryover, and the characterization of future

polymeric materials for use in semiconductor

technology.

2.4 This standard does not purport to address safety

issues, if any, associated with its use. It is the

responsibility of the users of this standard to establish

appropriate safety and health practices and determine

the applicability of regulatory limitations prior to use.

3 Referenced Documents

3.1 SEMI Documents

SEMI E19 — Standard Mechanical Interface (SMIF)

SEMI Minienvironment Terminology Workshop

Proceedings, April 2, 1993

4 Terminology

4.1 Box/Cassette/Minienvironment/Pod

4.2 DOP — Dioctylphthalate

4.3 Headspace — The volume above the sample

containing the gas to be analyzed

4.4 HPB — Hexaphenylbenzene

4.5 IMS — Ion Mobility Spectrometry

4.6 IMS/MS — Ion Mobility Spectrometry/Mass

Spectrometry

4.7 NS — Standardized Ground Jo int

4.8 SMIF (Standard Mechanical Interface) — The

interface plane between a pod and another

minienvironment as per SEMI E19.

4.9 PFA — Polyfluoroalkoxy

4.10 PP — Polypropylene

5 Summary of Method

5.1 This test method defines a fast, sensitive technique

for the determination of organic contamination from

minienvironments. The contamination is measured

directly from the silicon surface. Three important

aspects are covered:

a. Contamination due to the minienvironment alone,

b. Contamination from the use of minienvironments

for wafer processing, and

c. Contamination from future materials to be used in

semiconductor technology.

5.2 Silicon wafers are either placed in the

minienvironment or used for headspace sampling

experiments. The sample is heated and the target

compound is either desorbed or outgassed. These

compounds are swept by the carrier gas into the Ion

Molecule Reactor. Here the molecules are chemically

ionized under atmospheric pressure. The target ions are

separated in a drift cell by electrophoreses in the

gaseous state and detected by an electrometer.

Additionally, a quadrupole mass spectrometer could be

used as a second detector. The result is a quantitative

value for the total amount of organic surface

contamination.

6 Interferences

6.1 To adequately measure organic contaminants from

minienvironments, an extremely sensitive method for

analyzing volatiles is required. At this time, the only

analytical method meeting these requirements is IMS.

The absolute determination of organic contamination by

the IMS method is still limited, especially in the

presence of many analytes, but this proposed test

method permits the comparison of quantitative results

from different laboratories.

7 Apparatus

7.1 Minimum Requirements for the Ion Mobility

Spectrometer — For the successful performance of the

experiments using the IMS instrument, the following

requirements are essential:

— minimum length of the drift cell: 4 cm

— sample inlet has to be lockable (no sniffing

devices)

— sample desorption oven must have a programmable

temperature control

— the electronics must guarantee a linear

amplification of the observed signal

— intensity over at least five orders of magnitude

— documentation of all single measurement results.

7.2 Measuring Parameters — For measurements with

the ion mobility spectrometer, the following parameters

have to be used:

temperature of the desorption furnace: 200°C*

temperature of the drift cell and IMS detector:

205°C*

maximum dwell time or channel length corres-

ponding to minimum time resolution: 80 µs**

measuring time per spectrum: 40 ms*

(for 200 V/cm and 10 cm length of drift cell)

gatewidth: 200 µs**

number of scans: 2000**

drift gas and carrier gas: zero grade (synthetic) air*

• approx. 10 ppm H

• max 0.1 ppmv total hydrocarbons*

carrier gas flow: 100 mL/min* (for a diameter of

3.9 mm)

drift gas flow: 500 mL/min** (for a diameter of

4.25 cm)

* specified; ** suggested

8 Reagents

8.1 The chemicals must be of the described quality or

better and supplied with a certificate of analysis.

Benzene: ultrapure quality for trace residue analysis.

Minimum quality: pro analysi.

• content of benzene: min. 99.8%

• content of water: max. 0.02%

• nonvolatile residue: max. 0.0005%

Ethanol: ultrapure quality for trace residue analysis.

Absolute.

• content of ethanol: min. 99.8%

• content of water: max. 0.1%

• nonvolatile residue: max. 0.0005%

DOP: normal pure quality.

• content of DOP: better than 96%

HPB: normal pure quality.

• content of HPB: better than 96%

9 Safety Precautions

9.1 All preparation and measurement work has to be

done according to local regulations for laboratories.

10 Procedure

10.1 Preparation Tools and Auxiliaries — The

following equipment is needed for the preparation of

polymer headspace substrates:

• protective eye wear

• 1 fume cupboard

• 1 butane burner

• 2 pairs of crucible tongs made of stainless steel

• scalpel with changeable blades

• 4 pairs of cross tweezers with tips made of steel

• 1 metal vernier calliper

• Si-wafer-chips: formate 20 × 10 mm

• watch glass

• weighing bottle with lid, both made of glass

inner diameter: 80 mm

height: 30 mm