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SEMI E35.1-95 © SEMI 1995, 2004 2 compared dire ctly on the basis of particl es or other direct metrics such as uniformity. 5.2.3 The Cost of Equipm ent Ownership should o nly reflect Equipment Yield. The perce ntage of …

SEMI E35.1-95 © SEMI 1995, 2004 1

SEMI E35.1-95 (Withdrawn 0304)

GUIDE FOR COST OF EQUIPMENT OWNERSHIP COMPARISON

METRIC

NOTICE: This document was balloted and approved for withdrawal in 2004.

1 Purpose

1.1 The purpose of this guide is to provide a standard

constrained version of the Cost of Ownership for

Semiconductor Manufacturing Equipment Metrics

Guide to provide a baseline metric for comparing cost

effectiveness of competitive factory equipment

subsystems in the semiconductor industry. The major

constraints are the inclusion of only Equipment Yield

and the exclusion of the Cost of Yield Loss consisting

of defect limited yield and parametric yield.

1.2 The guide establishes well-defined practice to

facilitate cost comparisons of equipment by using

definitions, classifications and methods necessary to

build a useful cost of equipment ownership comparator

as a constraint version of SEMI E35. The guide should

facilitate communication about cost of ownership.

2 Scope

2.1 This guide is a subset of a full COO calculator as

presented in SEMI E35 and constitutes a fully

conforming standard constraint version. The baseline

metric is meant to reflect those equipment aspects over

which an equipment supplier has responsibility and

seeks to minimize aspects which couple costs for

individual equipment to the entire factory system. The

use of the metric is for competitive evaluation of

equipment sets to be used for a specific process step.

2.2 Effective use of the metric to build a COO model

requires identification of the constraints, parameter

values within the adopted category classification. The

primary calculators should, where possible, use direct

values for inputs rather than deriving them from

secondary models or using the default values provided

in Related Information 1 and 2 in SEMI E35. A COO

model requires data for many parameters. Default data

for the COO is provided within this document and may

be updated periodically through support documents.

3 Referenced Documents

3.1 SEMI Documents

SEMI E10 — Guideline for Definition and

Measurement of Equipment Reliability, Availability,

and Maintainability

SEMI E35 — Guideline for Cost of Ownership for

Semiconductor Manufacturing Equipment Metrics

SEMI Compilation of Terms

4 Terminology

All terminology in this guideline is defined in SEMI

E35.

5 Cost of Equipment Ownership Comparator

The Cost of Equipment Ownership Comparator

(CEOC) metric is the incremental cost added to a good

wafer or IC device flowing through a volume sized

process system embedded in a factory environment for

a specified lifetime. The metric is expressed as Cost per

Good Wafer Equivalent for one pass through the

system. CEOC should reflect the full cost of embedding

and operating in a factory environment a process

system needed to accommodate a specified number of

wafers but does not include defect yield or parametric

yield loss.

5.1 CEOC: Fixed and Recurring Costs — Determining

the Cost of Ownership requires enumerating all of the

Fixed and Recurring costs. Fixed costs are those

incurred once and are usually associated with the

acquisition and incorporation of equipment into the

factory. Recurring costs are those which arise on an

annual basis from the operation and maintenance of the

equipment.

5.2 Yield

5.2.1 Production yield (PY) is often tied to a large

number of factors which are principally the

responsibility of the IC manufacturer and equipment

comparisons for production yield should be done

directly in the context of the production flow. Yield is a

metric of the percentage of the wafer volume that

results in good wafers and enters the picture in a

number of ways which can complicate comparisons.

Yield-related comparisons of equipment should be dealt

with directly rather than lumping them into the CEO.

COST of

Embedding + Operating

CEO =

annualized

Fixed Costs

per system

annualized

Recurring Costs

per system

(

)

Volume Required

# Systems

Good Units

Per Year

5.2.2 Particles additions for example are often used as

a predictor of yield loss. Equipment should be

SEMI E35.1-95 © SEMI 1995, 2004 2

compared directly on the basis of particles or other

direct metrics such as uniformity.

5.2.3 The Cost of Equipment Ownership should only

reflect Equipment Yield. The percentage of wafers

which can be passed to the next step can be based on

any criteria, such as broken wafers or wafers

determined to be defective by inspection or test.

5.3 Life — Time over which the fixed and recurring

costs are spread for the annualized basis. Tax Life is

customarily used in COO based upon standard

accounting practice.

COO Lifetimes

1. Tax Lifetime - Depreciation

2. Equipment Production Lifetime

5.4 System Throughput — Wafers per hour capability

for the process system.

5.5 Volume Requirement

5.5.1 The volume requirement is the wafer or IC (unit)

flow to be processed. The volume requirement can be

derived from specification of the product wafers or IC

devices needed corrected for yield and the required

number of other wafers which might be designated as

test, dummy, or monitor wafers. One complication in

accurately dealing with the volume requirement is that

the volume of wafers actually reaching the equipment

will depend on the volume loss from equipment yield

for all the prior steps.

5.5.2 For CEOC, volume should be dealt with

parametrically based upon factory wafer starts. For

multi-chamber equipment, the impact of added

chambers to increase capacity should be included as

well as the impact of adding whole systems.

5.6 Good Wafer Equivalents (GWE) — GWE is

derived from the number of good product die at wafer

probe and is expressed as completely good wafers.

5.7 Systems Required — See SEMI E35.

6 Reporting Results

Conform to SEMI E35.

7 Limitations

7.1 Certain factors are more difficult than others to

accurately determine. Thus, the accuracy of a COO

calculation may be prone to a variety of errors or

omissions. In addition, line balance considerations are

not included in cost of ownership calculation.

7.2 A COO calculation may have more detail than

presented explicitly in this guide. The structure of the

guide however allows for the proper handling of these

situations.

8 Procedures

8.1 The CEOC algorithm requires the specification of

the volume level and the enumeration of appropriate

fixed and recurring costs associated with processing

that volume. The CEOC metric is a function expressed

as the sum of a number of categories which constitute a

classification system as given in SEMI E35. Each item

in the classification system should be defined, a method

for evaluating its expression given, and default values

or handling specified. The cost of equipment ownership

is a sum over the elements in the Category Table as

expressed in Equation 2 and defined in SEMI E35.

8.2 Each item in the classification system is defined, a

method for evaluating its expression given, and default

values or handling specified. All costs must be assigned

through the classification system and calculated per

system for the number of production hours.

CEOC

∑













Volume

Required

# Systems

# Good Units

er year













∑













Volume

Required

# Systems

# Good Units

er yea













(2)

NOTICE: These standards do not purport to address

safety issues, if any, associated with their use. It is the

responsibility of the user of these standards to establish

appropriate safety and health practices and determine

the applicability of regulatory limitations prior to use.

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 E43-0301

GUIDE FOR MEASURING STATIC CHARGE ON OBJECTS AND

SURFACES

This guide was technically approved by the Global Metrics Committee and is the direct responsibility of the

North American Metrics Committee. Current edition approved by the North American Regional Standards

Committee on November 22, 2000. Initially available at www.semi.org December 2000; to be published

March 2001. Originally published in 1995.

This document was entirely rewritten in 2001.

1 Purpose

1.1 The purpose is to establish a guide for

reproducible measurement of electrostatic charge(s) on

any surface or object, consistent with the scope and

limitations set forth below.

2 Scope

2.1 The measurement methods described herein can be

applied to characterize the general electrostatic charge

level(s) on objects and surfaces in all environments.

Acceptable instrumentation, calibration, and measure-

ment techniques are described in this document.

Appendices include background information on the

equipment specified and calibration procedure, as well

as information and advice on performing a useful

general static survey.

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 health practices and determine the

applicability or regulatory limitations prior to use.

3 Limitations

3.1 Direct measurement of charge usually requires the

use of a coulombmeter. Charges on an isolated

conductor can be measured by transferring the charge

into the coulombmeter by contacting the isolated

conductor with the coulombmeter input probe. Charges

on isolated conductors and insulators can be measured

by transferring the charged object into a Faraday

enclosure that is connected to the coulombmeter. These

measurements can be relatively precise if care is taken

in the transfer process to avoid changing the charge

level when making the measurements.

3.2 Direct measurement of charge is often impractical.

In these instances, charge is indirectly evaluated by

detecting the electrostatic field from a charged surface

using an electrostatic fieldmeter or an electrostatic

voltmeter.

3.3 This guide does not describe instrumentation and

techniques capable of making highly precise

measurement of electrostatic charge. It is not suitable

for measurement of electrostatic charge on small

objects, such as packaged devices (i.e., reading(s)

obtained are indicative/general area and not precise/

minute). No methods of preconditioning the surface

prior to measurements and no methods of character-

izing the basic electrostatic performance of materials,

such as tribocharging, resistance, and decay rate are a

part of this document. Measurements made using this

guide on the same surface or object may differ due to

differences in the environment or history of the surface

or object between the times any two measurements are

made.

4 Referenced Standards

4.1 None.

5 Terminology

5.1 electrostatic discharge (ESD) — the rapid

spontaneous transfer of electrostatic charge induced by

a high electrostatic field.

5.2 ground — a conducting connection between an

object, electrical equipment, and earth, such as the

portion of an electrical circuit of the same electrical

potential as earth.

5.3 grounded — connected to earth or some other

conducting body that serves in the place of earth.

6 Safety

6.1 Measurements of Very High Static Potentials (>

30,000 Volts) — Measurements of very high static

potentials (> 30,000 V) may need to be done at larger

distances to avoid exceeding the measurement range of

the meter and/or an ESD event to the meter.

6.2 Measurements on Moving Objects or Surfaces —

Care should be taken, when attempting to read

electrostatic charges on moving objects or surfaces, to

maintain correct distance and avoid any contact; this is

to assure “good” readings with no mechanical damage

or personal injury.

6.3 Measurements Using Electrostatic Voltmeters —

Avoid handling electrostatic voltmeter probes during