semi合集-English.pdf - 第4769页

SEMI C52-0301 © SEM I 2001 1 SEMI C52-0301 SPECIFICA TION FOR THE SHELF LIFE OF A SPECI ALTY GAS This specif ication was technic ally approved by the Global Ga ses Committee and is the direct responsib ility of the Europ…

SEMI C15-95 © SEMI 1995, 2002 5

detail, because such a calculation can be made by

applying procedures described elsewhere. The accuracy

required in validation will vary with the proposed

application of the moisture standard and may be left to

the discretion of the user of the procedure. It is

recommended that a propagation of errors calculation

be carried out to estimate the accuracy of the validation.

If no such calculation is made, and the minimum

criteria of the procedure are followed, it is estimated

that a validated moisture generator may output moisture

levels which differ from the true values by up to 20%.

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 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, SEMI

takes no position respecting the validity of any patent

rights or copyrights asserted in connection with any

item 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.

International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o

the contents in whole or in part is forbidden without express written

consent of SEMI.

SEMI C52-0301 © SEMI 20011

SEMI C52-0301

SPECIFICATION FOR THE SHELF LIFE OF A SPECIALTY GAS

This specification was technically approved by the Global Gases Committee and is the direct responsibility of

the European Gases Committee. Current edition approved by the European Regional Standards Committee on

December 20, 2000. Initially available at www.semi.org January 2001; to be published March 2001.

1 Purpose

1.1 The purpose of this document is to define

terminology and to recommend minimum periods for

the shelf lives of specialty gases. It is meant to provide

consistency in terminology among gas suppliers and to

provide a general guideline for users of these gases.

2 Scope

2.1 This document applies to the shelf life of properly

packaged, filled and analyzed specialty gases as stored

or supplied by a specialty gas manufacturer or supplier.

In this document, shelf life is viewed from a quality

point of view. The document does not address safety

aspects associated with the prolonged storage of gases.

2.2 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 Standards

None.

4 Terminology

4.1 container — a lecture bottle, cylinder, cylinder

pack, drum or any other vessel which is used to supply

a specialty gas.

4.2 residual level — The amount of product, as a

fraction of the fill weight or fill pressure, which should

be left in a container in order to minimize the impact on

manufacturing processes of the higher level of

impurities in the last gas fraction from a container.

4.3 shelf life — the period of time for which the

specification of a gas is guaranteed by the supplier,

starting from the time of analysis. It defines the period

for which the supplier guarantees the actual level of

impurities, as analyzed, to remain at or below the

specification limit for a particular gas grade.

5 Requirements

5.1 Factors Affecting the Shelf Life of a Specialty Gas

— Shelf life is a function of the following factors:

a. Thermal stability of the gas

b. Quality of the container and valve

• material selection

• leak tightness

c. Time-dependent reactions between

• gas and impurities

• gas and packaging materials

d. Filling and analytical operations

e. Transport and storage conditions

f. Amount of product in the container

5.1.1 The integrity of the valve is a key factor

determining the shelf life of a gas, in particular for low

vapor pressure gases. Time dependent reactions can be

significantly reduced by purification of the gas to a

level where impurities no longer have a significant

effect over time, and by selection of proper packaging

materials. Chemical and physical treatment of the

internal container surface and/or passivation of this

surface before filling also reduces the effect of time-

dependent reactions. For material and gas compatibility

information, please refer to the individual SEMI gas

standards.

5.2 Classification of Specialty Gases on the Basis of

Shelf Life — While there are a large number of

specialty gases used in semiconductor manufacturing,

for the purpose of defining shelf lives, they can be

divided into four groups. It should be noted that for

example chemically reactive gases are sometimes

classified as non-reactive in the table below as the

classification is done from a shelf-life point of view

only.

5.2.1 Non-reactive — Under normal storage

conditions, these gases do not react with ambient air,

the packaging materials or the impurities commonly

found in the specialty gas.

5.2.2 Reactive — These gases react either with

ambient air or standard packaging materials.

5.2.3 Corrosive — These gases react with packaging

materials usually in the presence of traces of moisture.

5.2.4 Unstable — These gases are thermally unstable

and spontaneously decompose over time.

SEMI C52-0301 © SEMI 2001 2

Table 1 Classification of Specialty Gases on the

Basis of Shelf Life

Non-

reactive

Reactive Corrosive Unstable

Air

CFH

AsH

GeH

SeH

SiH

BCl

ClF

GeF

HBr

HCl

SiCl

SiF

5.3 Guaranteed Shelf Life Period — The following

guaranteed shelf life periods are recommended as a

minimum.

Table 2 Guaranteed Shelf Life Period

Non-

reactive

Reactive Corrosive Unstable

36 months 24 months 18 months 6 months

5.3.1 When proper packaging materials are chosen and

the container is properly prepared (and passivated),

impurity levels should in theory remain constant over

time for an electronics grade specialty gas with the

exception of the thermally unstable gases. For this

reason, no maximum shelf life periods are

recommended as these will depend on the level of

analytical data collected by the manufacturer or

supplier.

5.4 Mixtures — The shelf life of a mixture is

recommended to be equal to the shelf life of the

component in the mixture with the lowest shelf life. For

example, the minimum shelf life of a reactive gas in a

non-reactive gas matrix would be 24 months. The shelf

life of a mixture should apply both to the impurity

specifications and to the assay of the mixture.

5.4.1 Special attention should be paid to the

preparation of the package for mixtures containing less

than 1,000 ppm of a component. At such levels,

adsorption effects may reduce the shelf life and

minimization of the package internal surface roughness

and/or passivation of the surface may be required.

5.5 Residual Level — The impact of the depletion of a

container on impurity levels is still a matter of debate

among gas suppliers. In general, the impurity levels of

the first gas fraction from a container will differ from

the last gas fraction. In particular moisture levels tend

to rise at lower gas pressures as a result of the relative

increase in importance of the internal container wall

and its adsorbed moisture. In addition, in liquefied

gases the co-existence of both a gas phase and a liquid

phase can have a measurable effect on the distribution

of impurities over the gas fractions. It is argued that at

the point of liquid-dry some impurities, which prefer

solution in the liquid phase over the gas phase, may see

a dramatic rise. It is therefore recommended to always

leave an amount of product in the container and to

avoid a situation of “liquid dry” (i.e., when all of the

liquid phase of a liquefied gas has been used).

NOTICE: SEMI makes no warranties or

representations as to the suitability of the specification

set forth herein for any particular application. The

determination of the suitability of the specification 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 mentioned herein. These

specifications are subject to change without notice.

The user’s attention is called to the possibility that

compliance with this specification may require use of

copyrighted material or of an invention covered by

patent rights. By publication of this specification, SEMI

takes no position respecting the validity of any patent

rights or copyrights asserted in connection with any

item mentioned in this specification. Users of this

specification 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.

International), 3081 Zanker Road, San Jose, CA 95134. Reproduction o

the contents in whole or in part is forbidden without express written

consent of SEMI.