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SEMI M50-1104 © SEMI 2001, 2004 1 SEMI M50-1104 TEST METHOD FOR DETERMIN ING CAPTURE RA TE AND FALSE COUNT RATE FOR SURFACE SCANNI NG INSPECTION SYSTEMS BY THE OVERLAY METHOD This test method was technically approved by …

SEMI M49-0704 © SEMI 2001, 2004

APPENDIX 1

SCALING MODELS

NOTICE: The material in this appendix is an official part of SEMI M49 and was approved by full letter ballot procedures on

May 14, 2004.

Table A1-1 Scaling models used in Tab. 3.1 for the technology nodes 130 to 65 nm

130 nm node 90 nm node 65 nm node

Property

nominal nominal nominal

1.1 Thickness (200 mm wafers),

µm

725 no scaling no scaling

1.2 Thickness (300 mm wafers),

µm

775 no scaling no scaling

1.3 GBIR, nm 1000 no scaling no scaling

1.4 Site Size local flatness, mm

25*25 26*8 26*8

1.4.1 SBIR, including

partial sites, nm

250

2/3 of (120 nm + max. SFQR

per ITRS)

2/3 of (120 nm + max. SFQR

per ITRS)

1.4.2 SFQR, including

partial sites, nm

130

2/3 of max value acc. to

ITRS

2/3 of max value acc. to

ITRS

1.5 Warp, µm

30 no scaling no scaling

1.6 Nanotopography, 2 mm, P-V,

nm, at 0.05% defective area

2/3 of max value acc. to

ITRS

2/3 of max value acc. to

ITRS

1.7 Nanotopography, 10 mm, P-V,

nm, at 0.05% defective area

70 70% of previous generation

70% of previous generation

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the risk of infringement of such rights, are entirely their own responsibility.

10 120 nm is calculated to be the average taper contribution to SBIR for 130 nm node (SBIR – SFQR). This value is kept constant for the 90 and

65 nm technology nodes.

11 ITRS provides maximum specifications regarding starting material requirements. This maximum value is assumed to be equivalent to the

upper end of range recommended for reference wafers as defined in 6.5.17. The nominal value is then 2/3 of the maximum value.

12 ITRS provides no guidance regarding Nanotopography of 10 mm analysis area

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SEMI M50-1104 © SEMI 2001, 2004 1

SEMI M50-1104

TEST METHOD FOR DETERMINING CAPTURE RATE AND FALSE

COUNT RATE FOR SURFACE SCANNING INSPECTION SYSTEMS BY

THE OVERLAY METHOD

This test method was technically approved by the Global Silicon Wafer Committee and is the direct

responsibility of the North American Silicon Wafer Committee. Current edition approved by the North

American Regional Standards Committee on August 16, 2004. Initially available at www.semi.org

September 2004; to be published November 2004. Originally published November 2001.

1 Purpose

1.1 SEMI M52 defines capture rate (CR) requirements

to be met by a scanning surface inspection system

(SSIS) to be used for the 130 nm technology

generation. Similar requirements appear in

specifications for SSISs to be used in other

applications.

1.2 This test method provides a framework for the

determination of the CR, false count rate (FCR) and

cumulative false count rate (CFCR) of an SSIS as a

function of latex sphere equivalent (LSE) size of

localized light scatterers (LLS).

NOTE 1: In the context of this document the term “size”

refers to the LSE diameter.

2 Scope

2.1 This test method defines the SSIS capture rate and

discusses its usage in industry specifications.

2.2 This test method addresses calculating and

reporting SSIS capture rate from measurements of

either PSL depositions or other LLS on wafers in LSE

units.

2.3 Specific wafer surfaces (by wafer product, type of

film or type of polish) that may affect the measured

capture rate and false count rate of an SSIS are to be

agreed upon between suppliers and users.

NOTICE: 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 or other limitations prior

to use.

3 Limitations

3.1 This test method is limited to use on unpatterned

wafers.

3.2 This test method is limited to use on calibrated

scanners operated in a production mode.

4 Referenced Standards

4.1 SEMI Standards

SEMI E89 — Guide for Measurement System

Capability Analysis

SEMI M52 — Guide for Specifying Scanning Surface

Inspection Systems for Silicon Wafers for the 130-nm

Technology Generation

SEMI M53 — Practice for Calibrating Scanning

Surface Inspection Systems Using Certified

Depositions of Monodisperse Polystyrene Latex Sphere

on Unpatterned Semiconductor Wafer Surfaces

4.2 ISO Standard

ISO Guide 30:1992 — Terms and Definitions Used in

Connection with Reference Materials

NOTICE: Unless otherwise indicated, all documents

cited shall be the latest published versions.

5 Terminology

5.1 Definitions

5.1.1 capture rate (CR) — the probability that an SSIS

detects an LLS of latex sphere equivalent (LSE) signal

value at some specified SSIS operational setting.

5.1.2 certified reference material (CRM) — reference

material, accompanied by a certificate, one or more of

whose property values are certified by a procedure

which establishes its traceability to an accurate

realization of the unit in which the property values are

expressed, and for which each certified value is

accompanied by an uncertainty at a stated level of

confidence. [ISO Guide 30:1992]

5.1.3 cumulative false count rate (CFCR) — number of

false counts of size S

, or larger, that are expected to be

recorded by an SSIS at some specified operational

setting as a function of S

. CFCR may be found by

averaging false counts over multiple scans.

1 International Organization for Standardization, ISO Central

Secretariat, 1, rue de Varembé, Case postale 56, CH-1211 Geneva 20,

Switzerland. Telephone: 41.22.749.01.11; Fax: 41.22.733.34.30

Website: www.iso.ch

SEMI M50-1104 © SEMI 2001, 2004 2

5.1.4 false count (FC) — laser-light scattering event

that arises from instrumental causes rather than from

any feature on or near the wafer surface; also called

false positive.

5.1.4.1 Discussion — False counts would not be

expected to occur at the same point on the wafer surface

during multiple inspection scans, and hence they could

be considered as random “noise” that could be identi-

fied by examining the results of repeated scans.

5.1.5 false count rate (FCR) — mean total number of

false counts per wafer that an SSIS reports at some

specified SSIS operational setting.

5.1.6 repeat counts — LLSs that are found in a later

scan within the scanner XY uncertainty distance of their

location as found on an earlier scan.

5.1.6.1 Discussion — The implication is that if defect

density is low enough, then a repeat count results from

detecting the same LLS event again and is not the result

of SSIS noise. Besides the absolute position of the

LLS, an additional matching condition may be the LSE

signal of the LLS.

5.1.7 scanner XY uncertainty — square root of the

sum of the squares of the one-sigma standard deviations

in the reported X and Y locations of the SSIS under test,

as determined under repeatability conditions.

5.1.8 true count — laser-light scattering event that

arises from the localized light scatterers (LLS) being

investigated.

6 Summary of Method

6.1 The XY coordinate uncertainty of the SSIS under

test is either known or determined under repeatability

conditions, without removing the wafer from the stage

between scans.

6.2 The reference wafer to be used in this test is

selected.

6.3 The selected wafer is scanned Z times on the SSIS

under test. The first two scans are used to qualify the

reference wafer before continuing with the remaining

Z2 scans.

NOTE 2: Typical values for Z are between 30 and 100 scans.

6.4 The scans are analyzed to determine and record the

number of times each LLS event occurs in each

location (to within a distance approximately six times

the scanner XY uncertainty) during the Z scans. The

capture rate, standard size deviation, false count rate,

and cumulative false count rate are determined from

this data set.

7 Apparatus

7.1 SSIS under test — installed in its position of use

with clean room rating recommended by the

manufacturer.

7.2 Off-line analysis software program — to track each

observed count and determine the capture rate, standard

size deviation, the number of false counts at each LLS

size, the false count rate, and the cumulative false count

rate.

NOTE 3: The analysis software may be incorporated into the

SSIS, if desired.

8 Test Specimens

8.1 Use any wafer with (1) natural LLS with density

<10 LLS/cm

and (2) a surface roughness typical of the

wafers to be measured in production (see Section 2.3).

8.1.1 The minimum distance between any two LLS

found during any one scan and used in the data set to be

analyzed shall be larger than six times the scanner XY

uncertainty. Clusters of LLS (found in any one scan

and closer together than six times the scanner XY

uncertainty) and scratches must be excluded during the

analysis.

8.1.2 Determine the scanner XY uncertainty from

previous knowledge, from the scanner manufacturer

specifications, or from the positional accuracy

determined under repeatability conditions in accordance

with Appendix 1.

8.2 Alternatively, a wafer with deposited polystyrene

latex spheres can be used to evaluate the capture rate

more accurately at a specific particle size. The same

particle density, particle spacing, and defect cluster

conditions as in Section 8.1 should be observed.

NOTE 4: The wafer with deposited PSL spheres may or may

not be certified reference material.

9 Procedure

9.1 Qualify the wafer for appropriate LLS number (see

Section 8.1) prior to taking CR and CFCR data as

follows:

9.1.1 Scan the wafer once and determine position, P

and size, S

of each of the M

detected LLS events with

m = [1, 2, … M

9.1.2 To determine that there are enough repeating

LLS events to make the CR calculation meaningful,

scan the wafer a second time and compare the detected

LLS events with respect to the positions of those

detected during the first scan. Define the total number

of LLS events that repeat their position in the first scan

to within six times the scanner XY uncertainty as M

Consider the wafer qualified for the test if the share of