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SEMI M6-1000 © SEMI 1981, 2000 5 8.2 In the i nterest of controlling in s p e ction cost s, the supplier and the pu rchaser may agree that the material shall be certified as ‘ capable of meeting’ certain requirements . I…

SEMI M6-1000 © SEMI 1981, 2000 4

6.4 Wafer defect limits — See Tab le 1.

Table 1 Wafer Defect Limits

Item Characteristics* Max Defect Limits Notes

1Saw Marks

20 µm TIR

2Area

Contamination

To be determined

3Edge

Chips/Indents

2 per wafer max

up to l mm wide

and l mm deep

4 Cracks/crow's feet None

* Characteristics are defined in SEMI M1, Section 10.

NOTE 1: The outer l mm (0.040") is excluded from these criteria.

NOTE 2: Excluding conchoidal chips.

6.5 Sampling

6.5.1 Unless otherwise specified, Practice E 122 shall

be used.

6.5.1.1 When so specified, appropriate sample sizes

shall be selected from each lot in accordance with

ANSI/ASQC Z1.4. Each quality characteristic shall be

assigned an acceptable quality level (AQL) and lot

tolerance percent defective (LTPD) value in accordance

with ANSI/ASQC Z1.4 definitions for critical, major,

and minor classifications. If desired and so specified in

the contract or order, each of these classifications may

alternatively be assigned cumulative AQL and LTPD

values. Inspection levels shall be agreed upon between

the supplier and the purchaser.

7 Test Methods

NOTE 6: Silicon wafers are extremely fragile. While the

mechanical dimensions of a wafer can be measured by use of

tools such as micrometer calipers and other conventional

techniques, the wafer may be damaged physically in ways that

are not immediately evident. Special care must therefore be

used in the selection and execution of measurement methods.

7.1 Length, Width, or Diameter — Determine the

diameter of circular wafers in accordance with ASTM

Test Method F 613. Determine the side length of square

wafers by a method agreed upon between the supplier

and the purchaser.

7.2 Thickness, Center Point — Determine in

accordance with ASTM Test Methods F 533 or DIN

50441-1.

7.3 Thickness Variation — Determ ine in accordance

with ASTM Test Methods F 533 or F 657.

7.4 Structural Class — Determine the structural class

by a method agreed upon between the supplier and the

purchaser.

7.5 Surface Orientation — Determine in accordance

with ASTM Test Methods F 26 or DIN 50433-1, DIN

50433-2 and DIN 50433-3.

7.6 Conductivity Type — Determine in accordance

with ASTM Test Methods F 42 or DIN 50432.

7.7 Resistivity — Determine by methods agreed upon

between the supplier and the purchaser.

NOTE 7: Resistivity of wafers is most appropriately

determined for referee purposes by ASTM Method F 84 or

DIN 50431. Reliable measurements with these methods can

only be made in regions of a wafer which contain no grain

boundaries; these methods are therefore not appropriate for

multicrystalline material. Under some circumstances these

tests may be considered destructive, and an alternative means

may be required. One non-destructive test is ASTM Test

method F 673, having a range from 0.001 to 100 Ω-cm. This

method is relatively insensitive to the presence of grain

boundaries and is recommended for all material types.

Another nondestructive test is ASTM Test Method F 398.

This method is limited to carrier concentrations in the ranges

from 1.5 × 10

-3

to 1.5 × 10

-3

for n-type silicon and

from 3 × 10

-3

to 5 × 10

-3

for p-type, and has only

moderate inter-laboratory precision. Other available methods

include ASTM Test methods F 43 or DIN 50430 (referee

methods requiring a bar-shaped sample).

7.8 Other Impurities — Determine by methods agreed

upon between the supplier and the purchaser.

NOTE 8: ASTM Test Methods F 1188, F 1619 and DIN

50438-1 are specific tests for oxygen. ASTM F 1391 and DIN

50438-2 are specific tests for carbon; special thick test

specimens are necessary.

7.9 Minority Carrier Diffusion Length — Determine

by methods agreed upon between the supplier and the

purchaser.

NOTE 9: Methods for minority carrier diffusion length are

listed in ASTM F 391.

7.10 Minority Carrier Lifetime — D etermine by

methods agreed upon between the supplier and the

purchaser.

NOTE 10: Methods for minority carrier lifetime

measurements are given in ASTM F 28 (bulk material),

ASTM F 1535 (wafers) and JEIDA-53 (wafers). As the wafer

methods measure an effective lifetime, the sample preparation

(surface passivation) and measurement conditions will

influence the results and must be considered.

8 Certification

8.1 Upon request of the purchaser in the contract or

order, a manufacturer’s or supplier’s certification that

the material was manufactured and tested in accordance

with this specification, together with a report of the test

results, shall be furnished at the time of shipment.

8.2 In the interest of controlling in spection costs, the

supplier and the purchaser may agree that the material

shall be certified as ‘capable of meeting’ certain

requirements. In this context, ‘capable of meeting’ shall

signify that the supplier is not required to perform the

appropriate tests in Section 7. However, if the purchaser

performs the test and the material fails to meet the

requirement, the material may be subject to rejection.

9 Packing and Package Lab eling

9.1 Special packing requirements shall be subject to

agreement between the supplier and the purchaser.

Otherwise all wafers shall be handled, inspected, and

packed in such a manner as to avoid chipping,

scratches, and contamination, and in accordance with

the best industry practices to provide ample protection

against damage during shipment.

9.2 The wafers supplied under these specifications

shall be identified by appropriately labeling the outside

of each box or other container and each subdivision

thereof in which it may reasonably be expected that the

wafers will be stored prior to further processing.

Identification shall include as a minimum the nominal

diameter, conductivity type, dopant, orientation,

resistivity range, and lot number. The lot number, either

(1) assigned by the original manufacturer of the wafers,

or (2) assigned subsequent to wafer manufacture but

providing reference to the original lot number, shall

provide easy access to information concerning the

fabrication history of the particular wafers in that lot.

Such information shall be retained on file at the

manufacturer’s facility for at least one year after that

particular lot has been accepted by the purchaser.

Figure 1

Rectangular Mainly Square Photovoltaic Solar Cell Silicon Wafer Dimensions

Table 2 Rectangular Mainly Square Photovoltaic Solar Cell Silicon Wafer Dimensions (letters as in Figure 1)

Nominal Size (mm) Dimensions (mm)

ABCD

Max. Min. Max. Min. Max. Min. Max. Min.

100 101 99 101 99 142.8 140.0 2.0 0.5

125 126 124 126 124 187.2 175.4 2.0 0.5

150 151 149 151 149 213.5 210.7 2.0 0.5

200 201 199 201 199 284.3 281.4 2.0 0.5