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SEMI M49-0704 © SEMI 2001, 2004 6 7.2 Other Docume nts Evaluating Automated Wafer Measurement Instruments , SEMATECH 6 , Technology Transfer 941 12638A-XFR Metrology Tool Gauge Study Procedure f or th e International 300…

SEMI M49-0704 © SEMI 2001, 2004

6.5.10 In addition two levels of systematic off-set

between different tools are defined:

6.5.10.1 matching tolerance (difference of means ∆

)

6.5.10.2 correlation (regression curve)

6.5.11 Explicitly specified in the present document are

only level 3 variability σ

and matching tolerance ∆

they correspond to the utilization of measurement

equipment for wafer manufacturing most closely. The

supplier of a specific tool may optionally provide

specifications for level 1 and/or level 2 variability,

respectively.

6.5.12 Level 3 variability σ

and matching tolerance ∆

are specified with respect to anticipated specifications

for wafer geometry and flatness as given in Table 3 for

a reference wafer.

6.5.13 In the present document P/T-ratios are used for

specifying level 3 variability σ

6.5.13.1 A precision-to-tolerance ration P/T less than

10% at 6σ is recommended in SEMI M27 for

metrology equipment. This would be an extremely

demanding specification for flatness and geometry

measurement tools. In addition, flatness characterisitics

of Si wafers are typically described by a single sided

distribution with the median approaching zero, the

lower specification boundary. Therefore two grades that

are based on 3σ criteria, instead on 6σ, are

recommended for such tools in the present document:

• grade A: P/T < 10%, 3σ

• grade B: P/T < 20%, 3σ

6.5.13.2 The individual measurement features a tool

provides may be graded differently, e.g. SFQR might

meet grade A, but SBIR only grade B. This has to be

indicated appropriately in the tools’ technical

specifications.

6.5.14 Matching tolerance is specified to be less or

equal to 1.5σ

of level 3 variability. This corresponds to

a greater than 99% probability that the difference of any

individual measurement results obtained with two

different tools is smaller or equal to 5σ

6.5.15 The target for bias is a range of ± 1.5σ

with

respect to a certified value provided appropriate

reference materials are available. This corresponds to a

greater than 99% probability that any individual

measurement is in the range of ± 4σ

around the

certified value when a reference material is tested.

6.5.16 Reference material with a series of surface

features with appropriate height and half width is

required to verify bandwidth of a measurement tool.

The height of the features corresponds to the wafer

specification as outlined in Table 3.

6.5.17 The specifications of the measurement

equipment are verified by using wafers the parameters

of which are in a range, the upper limit of which

corresponds to 1.5 times anticipated wafer

specification, the lower limit to 0.5 of anticipated wafer

specification. These are listed in Table 3 as Reference

Wafer Specifications.

NOTE 5: The edge region of wafers represents the most

challenging area for meeting the desired performance

characteristics. This is because of the larger surface geometry

variations in the region near the edge, e.g. from polishing roll-

off.

6.5.18 Reference Wafers — The specifications of the

measurement equipment are verified by using reference

wafers with properties covering the range given in

Section 1 of Table 3. All reference wafers shall meet

the thickness and warp requirements listed in the table

but different wafers may be used to meet the flatness

and nanotopography requirements. For site related

specifications not all sites must fall within the range,

but the appropriate sites to be tested should be

indicated. In all cases, at least three wafers in the range

of values for each property shall be employed in the

testing.

6.5.19 Verification of bias, matching tolerance and the

various levels of variability are performed with

equipment which is calibrated according to the

supplier's procedures and which is under statistical

process control.

6.5.20 Compatibility of two tools is considered to be

satisfactory when the specifications of the older tool are

met with the newer tool operating in the emulation

mode.

6.5.21 The quality of a correlation between different

measurement equipment is not specified in the present

document.

7 Related Documents

7.1 ASTM Documents

E 177 — Standard Practice for Use of the Terms

Precision and Bias in ASTM Test Methods

E 456 — Standard Terminology for Relating to Quality

and Statistics

SEMI M49-0704 © SEMI 2001, 2004 6

7.2 Other Documents

Evaluating Automated Wafer Measurement Instruments, SEMATECH

, Technology Transfer 94112638A-XFR

Metrology Tool Gauge Study Procedure for the International 300 mm Initiative (I300I), International 300 mm

Initiative

, Technology Transfer #97063295A-XFR

International Technology Roadmap for Semiconductors: 1999 edition

ISO 3274: 1996 — Geometrical Product Specifications (GPS) – Surface Texture: Profile method – Nominal

characteristic of contact (stylus) instruments

Table 1 Generic Equipment Characteristics

Item Recommended Specification Comment References

1 WAFER HANDLING

1.1 Robot End-Effector optional wafer edge or backside contact edge as defined

by SEMI M1

1.2 Scan Stage optional wafer edge or backside contact edge as defined

by SEMI M1

1.3 Wafer Contact Materials contact materials to leave metals and

organics on wafers < as defined in ITRS 99

1.4 Wafer Detection protection of accidental contact due to e.g.,

cross-slotting double slotting, protrusions,

etc.

1.5 Wafer Rotational Alignment random in, aligned out

1.6 Number of Cassette Stations 2–4, arbitrary sender/receiver assignment

1.7 Type of Cassettes open, FOUP/SMIF, FOSB to be specified

alternatively

1.8 Cassette Loading manual/guided vehicle, conveyor belt

1.9 Automatic Cassette ID user specific

1.10 Wafer Seating vertical or off-horizontal during setting

cassette on

station by

operator

1.11 Cassette Filling Modes random access and loading, programmable

empty slot filling

1.12 Automatic Wafer ID

reading

user specific

1.13 Particulate Contamination < 0.001 PWP per cm

, > 90 nm LSE front,

and > 120 nm LSE backside (See NOTE 1.)

verify with

mirror polished

wafer surfaces

SEMI E14

2 RELIABILITY

2.1 MTBF > 2000 h SEMI E10

2.2 MTTA > 4 h SEMI E10

2.3 MTTR according to service contract SEMI E10

2.4 Availability > 98% per year

2.5 Uptime > 160 h/w

2.6 Response Time according to service contract

2.7 Statistical Process Control

(SPC) performance

automated

6 International Sematech, 2706 Montopolis Drive, Austin, Tx. 78741-6499, USA

7 SEMATECH, 3101 Industrial Terrace Suite 106, Austin TX 78758

8 More recent versions of the ITRS are available from the homepage of International Sematech: www.sematech.org

Item Recommended Specification Comment References

2.8 Statistical Process Control

(SPC) machine parameters

automated

3 PROCEDURAL

3.1 Acceptance Testing user specific

3.2 Transport and Assembly user specific

3.3 Quality Assurance supplier conforming with ISO 9000/9001 ISO 9000/9001

3.4 Warranty > 1 y

3.5 Test Certificates user specific

3.6 Spares Availability > 10 y

3.7 Change Control supplier conforming with ISO 9000/9001 ISO 9000/9001

4 DOCUMENTATION

4.1 Installation tbd

4.2 Operation tbd

4.3 Service tbd

5 COMPUTER, USER INTERFACE, CONNECTIVITY

5.1 Computer Operating System - Microsoft Windows NT 4.0 or higher, or

- Unix

5.2 Display cleanroom compatible, class 10 (Federal

Standard) or class 4 (ISO), respectively

FED-STD 209E

ISO 14644-1

5.3 Keyboard cleanroom compatible, class 10 (Federal

Standard) or class 4 (ISO), respectively

FED-STD 209E

ISO 14644-1

5.4 Pointing Device cleanroom compatible, class 10 (Federal

Standard) or class 4 (ISO), respectively

FED-STD 209E

ISO 14644-1

5.5 Printer cleanroom compatible, class 10 (Federal

Standard) or class 4 (ISO), respectively

FED-STD 209E

ISO 14644-1

5.6 Data Processing - reprocessing of data

- parallel processing in different modes

during measurement including sorting

- multiprocessing: e.g. recipe editing,

up/downloading during measurements

different modes

refer to data

evaluation e.g.

for two

different site

patterns, or

different

emulation

modes

5.7 Data Access - access to basic measurement results: e.g

thickness map, height map

- data available at SECS/GEM/HSMS

interface in real time

refers to all

functions as

defined in

Table 3

SEMI E5

SEMI E30

SEMI E37

5.8 Data Analysis

(Online/Offline)

on-line/off-line

5.9 Recipe Control - complete recipe generation off-line without

machine specific data (calibration curves)

- off-line recipe editing

- remote recipe control by host computer

- recipes are compatible between different

software versions