IEC 62276:2012

IEC 62276 ®
Edition 2.0 2012-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Single crystal wafers for surface acoustic wave (SAW) device applications –
Specifications and measuring methods

Tranches monocristallines pour applications utilisant des dispositifs à ondes
acoustiques de surface (OAS) – Spécifications et méthodes de mesure

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IEC 62276 ®
Edition 2.0 2012-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Single crystal wafers for surface acoustic wave (SAW) device applications –

Specifications and measuring methods

Tranches monocristallines pour applications utilisant des dispositifs à ondes

acoustiques de surface (OAS) – Spécifications et méthodes de mesure

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX X
ICS 31.140 ISBN 978-2-83220-433-7

– 2 – 62276 © IEC:2012
CONTENTS
FO R EW O RD . 5
INT R O D UCT IO N . 7
1 Sc op e . 8
2 Normative references . 8
3 Terms and definitions . 8
3.1 Single crystals for SAW wafer . 8
3.2 Terms and definitions related to LN and LT crystals . 9
3.3 Terms and definitions related to all crystals . 9
3.4 Flatness . 10
3.5 Definitions of appearance defects. 13
3.6 Other terms and definitions . 13
4 Requirements . 15
4.1 Material specification . 15
4.1.1 Synthetic quartz crystal . 15
4.1.2 LN . 15
4.1.3 LT. 15
4.1.4 LBO, LGS . 15
4.2 Wafer specifications . 15
4.2.1 General . 15
4.2.2 Diameters and tolerances . 15
4.2.3 Thickness and tolerance . 15
4.2.4 Orientation flat . 16
4.2.5 Secondary flat . 16
4.2.6 Back surface roughness . 16
4.2.7 Warp . 16
4.2.8 TV5 or TTV . 16
4.2.9 Front (propagation) surface finish . 17
4.2.10 Front surface defects . 17
4.2.11 Surface orientation tolerance . 18
4.2.12 Inclusions . 18
4.2.13 Etch channel density and position of seed for quartz wafer . 18
4.2.14 Bevel . 18
4.2.15 Curie temperature and tolerance . 18
4.2.16 Lattice constant . 18
4.2.17 Bulk resistivity (conductivity) for reduced LN and LT . 18
5 Sampling plan . 19
5.1 Sampling . 19
5.2 Sampling frequency . 19
5.3 Inspection of whole population . 19
6 Test methods . 19
6.1 Diameter . 19
6.2 T hic k nes s . 19
6.3 Dimension of OF . 19
6.4 Orientation of OF . 20
6.5 TV5 . 20
6.6 Warp . 20

62276 © IEC:2012 – 3 –
6.7 TTV . 20
6.8 Front surface defects. 20
6.9 Inclusio ns . 20
6.10 Back surface roughness . 20
6.11 Orientation . 20
6.12 Curie temperature . 20
6.13 Lattice constant . 20
6.14 Bulk resistivity . 20
7 Identification, labelling, packaging, delivery condition . 21
7.1 Packaging . 21
7.2 Labelling and identification . 21
7.3 Delivery condition . 21
8 Measurement of Curie temperature . 21
8.1 General . 21
8.2 DTA method . 21
8.3 Dielectric constant method . 22
9 Measurement of lattice constant (Bond method) . 23
10 Measurement of face angle by X-ray . 24
10.1 Measurement principle . 24
10.2 Measurement method . 25
10.3 Measuring surface orientation of wafer . 25
10.4 Measuring OF flat orientation . 25
10.5 Typical wafer orientations and reference planes . 25
11 Measurement of bulk resistivity . 26
11.1 Resistance measurement of a wafer . 26
11.2 E l ec tr od e . 26
11.3 Bulk resistivity . 27
12 Visual inspections . 27
12.1 Front surface inspection method . 27
Annex A (normative) Expression using Euler angle description for piezoelectric single
crystals . 29
Annex B (informative) Manufacturing process for SAW wafers . 33
Bibliography . 40

Figure 1 – Wafer sketch and measurement points for TV5 determination . 10
Figure 2 – Schematic diagram of TTV . 11
Figure 3 – Schematic diagram of warp . 11
Figure 4 – Example of site distribution for LTV measurement . 12
Figure 5 – LTV value of each site. 12
Figure 6 – Schematic of a DTA system . 22
Figure 7 – Schematic of a dielectric constant measurement system . 22
Figure 8 – The Bond method . 24
Figure 9 – Measurement method by X-ray . 24
Figure 10 – Relationship between cut angle and lattice planes . 25
Figure 11 – Measuring circuit . 26
Figure 12 – Resistance measuring equipment . 26

– 4 – 62276 © IEC:2012
Figure 13 – Shape of electrode . 27
Figure A.1 – Definition of Euler angles to rotate coordinate system (X, Y, Z) onto
) . 30
( x , x , x
1 2 3
Figure A.2 – SAW wafer coordinate system . 30
Figure A.3 – Relationship between the crystal axes, Euler angles, and SAW orientation
for some wafer orientations . 32
Figure B.1 – Czochralski crystal growth method . 34
Figure B.2 – Example of non-uniformity in crystals grown from different starting melt
compositions . 36
Figure B.3 – Schematic of a vertical Bridgman furnace and example of temperature
d is tr i bu t io n . 37

Table 1 – Description of wafer orientations . 14
Table 2 – Roughness, warp, TV5 and TTV specification limits . 17
Table 3 – Crystal planes to determine surface and OF orientations . 25
Table 4 – Electrode size . 27
Table A.1 – Selected SAW substrate orientations and corresponding Euler angles . 31

62276 © IEC:2012 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SINGLE CRYSTAL WAFERS FOR SURFACE ACOUSTIC
WAVE (SAW) DEVICE APPLICATIONS –
SPECIFICATIONS AND MEASURING METHODS

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62276 has been prepared by IEC technical committee 49:
Piezoelectric, dielectric and electrostatic devices and associated materials for frequency
control, selection and detection.
This second edition cancels and replaces the first edition of IEC 62276 published in 2005.
This second edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– terms and definitions are rearranged in accordance with the alphabetical order;
– “reduced LN” is appended to terms and definitions;
– “reduced LT” is appended to terms and definitions;
– reduction process is appended to terms and definitions.

– 6 – 62276 © IEC:2012
The text of this standard is based on the following documents:
FDIS Report on voting
49/1005/FDIS 49/1011/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
‡ reconfirmed,
‡ withdrawn,
‡ replaced by a revised edition, or
‡ amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
62276 © IEC:2012 – 7 –
INTRODUCTION
A variety of piezoelectric materials are used for surface acoustic wave (SAW) filter and
resonator applications. Prior to the 1996 Rotterdam IEC TC 49 meeting, wafer specifications
were typically negotiated between users and suppliers. During the meeting, a proposal was
announced to address wafer standardization. This standard has been prepared in order to
provide industry standard technical specifications for manufacturing piezoelectric single
crystal wafers to be used in surface acoustic wave devices.

– 8 – 62276 © IEC:2012
SINGLE CRYSTAL WAFERS FOR SURFACE ACOUSTIC
WAVE (SAW) DEVICE APPLICATIONS –
SPECIFICATIONS AND MEASURING METHODS

1 Scope
This International Standard applies to the manufacture of synthetic quartz, lithium niobate
(LN), lithium tantalate (LT), lithium tetraborate (LBO), and lanthanum gallium silicate (LGS)
single crystal wafers intended for use as substrates in the manufacture of surface acoustic
wave (SAW) filters and resonators.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60410:1973, Sampling plans and procedures for inspection by attributes
IEC 60758:2008, Synthetic quartz crystal – Specifications and guide for use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Single crystals for SAW wafer
3.1.1
as-grown synthetic quartz crystal
right-handed or left-handed single crystal quartz is grown hydrothermally
Note 1 to entry: The term “as-grown” indicates a state prior to mechanical fabrication.
Note 2 to entry: See IEC 60758 for further information concerning crystalline quartz.
3.1.2
lithium niobate
LN
single crystals approximately described by chemical formula LiNbO , grown by Czochralski
(crystal pulling from melt) or other growing methods
3.1.3
lithium tantalate
LT
single crystals approximately described by chemical formula LiTaO , grown by Czochralski
(crystal pulling from melt) or other growing methods
Note 1 to entry: This note applies to the French language only.

62276 © IEC:2012 – 9 –
3.1.4
lithium tetraborate
LBO
single crystals described by the chemical formula to Li B O , grown by Czochralski (crystal
2 4 7
pulling from melt), vertical Bridgman, or other growing methods
Note 1 to entry: This note applies to the French language only.
3.1.5
lanthanum gallium silicate
LGS
single crystals described by the chemical formula to La Ga SiO , grown by Czochralski
3 5 14
(crystal pulling from melt) or other growing methods
Note 1 to entry: This note applies to the French language only.
3.2 Terms and definitions related to LN and LT crystals
3.2.1
Curie temperature
T
c
phase transition temperature between ferroelectric and paraelectric phases measured by
differential thermal analysis (DTA) or dielectric measurement
3.2.2
single domain
ferroelectric crystal with uniform electrical polarization throughout (for LN and LT)
3.2.3
polarization process
electrical process used to establish a single domain crystal
Note 1 to entry: The polarization process is also referred to as “poling”.
3.2.4
reduction process
REDOX reaction to increase conductivity to reduce the harmful effects of pyroelectricity
3.2.5
reduced LN
LN treated with a reduction process
Note 1 to entry: Reduced LN is sometimes referred to as “black LN”.
3.2.6
reduced LT
LT treated with a reduction process
Note 1 to entry: Reduced LT is sometimes referred to as “black LT”.
3.3 Terms and definitions related to all crystals
3.3.1
lattice constant
length of unit cell along a major crystallographic axis measured by X-ray using the Bond
method
3.3.2
congruent composition
chemical composition of a single crystal in a thermodynamic equilibrium with a molten solution
of the same composition during the growth process

– 10 – 62276 © IEC:2012
3.3.3
twin
crystallographic defect occurring in a single crystal
Note 1 to entry: The twin is separated from the rest of the material by a boundary, generally aligned along a crystal
plane. The lattices on either side of the boundary are crystallographic mirror images of one another.
3.4 Flatness
3.4.1
fixed quality area
FQA
central area of a wafer surface, defined by a nominal edge exclusion, X, over which the
specified values of a parameter apply
Note 1 to entry: The boundary of the FQA is at all points (e.g. along wafer flats) the distance X away from the
perimeter of the wafer of nominal dimensions.
Note 2 to entry: This note applies to the French language only.
3.4.2
reference plane
plane depending on the flatness measurement and which can be any of the following:
a) for clamped measurements, the flat chuck surface that contacts the back surface of the
wafer;
b) three points at specified locations on the front surface within the FQA;
c) the least-squares fit to the front surface using all measured points within the FQA;
d) the least squares fit to the front surface using all measured points within one site
3.4.3
site
square area on the front surface of the wafer with one side parallel to the OF
Note 1 to entry: Flatness parameters are assessed either globally for the FQA, or for each site individually.
3.4.4
thickness variation for five points
TV5
measure of wafer thickness variation defined as the maximum difference between five
thickness measurements
1 6 mm
Index flat
2 5
Orientation flat
IEC  1990/12
Figure 1 – Wafer sketch and measurement points for TV5 determination
Note 1 to entry: Thickness is measured at the centre of the wafer and at four peripheral points shown in Figure 1.

62276 © IEC:2012 – 11 –
3.4.5
total thickness variation
TTV
difference between the maximum thickness and the minimum thickness

A
TTV = |A| – |B|
B
Reference plane || back surface
IEC  1991/12
Figure 2 – Schematic diagram of TTV
Note 1 to entry: The maximum thickness is represented by the letter A and the minimum thickness is represented
by the letter B in Figure 2 above.
Note 2 to entry: Measurement of TTV is performed under clamped conditions with the reference plane as defined in
3.4.2 a).
Note 3 to entry: This note applies to the French language only.

3.4.6
warp
maximum difference between a point on the front surface and a reference plane
Warp = |A| + |B|
3 point
reference plane B
A
Reference
point
IEC  1992/12
Figure 3 – Schematic diagram of warp
Note 1 to entry: Warp (shown in Figure 3) describes the deformation of an unclamped wafer.
Note 2 to entry: The reference plane is defined by 3-points as described in 3.4.2 b). Warp is a bulk property of a
wafer and not of the exposed surface alone.

3.4.7
sori
maximum difference between a point on the front surface and a reference plane.
Note 1 to entry: Sori describes the deformation of an unclamped wafer.
Note 2 to entry: In contrast to warp, in this case the reference plane is defined by a least-squares fit to the front
surface (3.4.2 c)).
3.4.8
local thickness variation
LTV
variation determined by a measurement of a matrix of sites with defined edge dimensions

– 12 – 62276 © IEC:2012
1 2 3 ….
…. n ….
IEC  1993/12
NOTE: All sites have their centres within the FQA.
Figure 4 – Example of site distribution for LTV measurement

LTV
Back surface
Site 1
Site 2 Site 3 . Site n
IEC  1994/12
Figure 5 – LTV value of each site
Note 1 to entry: Measurement is performed on a clamped wafer with the reference plane as defined in 3.4.2 a). A
site map example is shown in Figure 4. The value is always a positive number and is defined for each site as the
difference between the highest and lowest points within each site, as shown in Figure 5. For a wafer to meet an
LTV specification, all sites shall have LTV values less than the specified value.
Note 2 to entry: This note applies to the French language only.
3.4.9
percent local thickness variation
PLTV
percentage of sites that fall within the specified values for LTV
Note 1 to entry: As with the LTV measurement, this is a clamped measurement.
Note 2 to entry: This note applies to the French language only.
3.4.10
focal plane deviation
FPD
deviation measured relative to the 3-point reference plane
Note 1 to entry: The 3-point reference plane is defined in 3.4.2 b).
Note 2 to entry: The value obtained indicates the maximum distance between a point on the wafer surface (within
the FQA) and the focal plane. If that point is above the reference, the FPD is positive. If that point is below the
reference plane, the FPD is negative.
Note 3 to entry: This note applies to the French language only.

62276 © IEC:2012 – 13 –
3.5 Definitions of appearance defects
3.5.1
contamination
foreign matter on a surface of wafer which cannot be removed after cleaning
3.5.2
crack
fracture that extends to the surface and may or may not penetrate the entire thickness of the
wafer
3.5.3
scratch
shallow groove or cut below the established plane of the surface, with a length to width ratio
greater than 5:1
3.5.4
chip
region where material has been removed from the surface or edge of the wafer
Note 1 to entry: The size can be expressed by its maximum radial depth and peripheral chord length.
3.5.5
dimple
smooth surface depression larger than 3 mm diameter
3.5.6
pit
non-removable surface anomaly
EXAMPLE A hollow, typically resulting from a bulk defect or faulty manufacturing process.
3.5.7
orange peel
large featured, roughened surface visible to the unaided eye under diffuse illumination
3.5.8
acceptable quality level
AQL
maximum percent defective (or maximum number of defects per hundred units) that, for
purposes of sampling inspections, can be considered satisfactory as a process average
SOURCE: IEC 60410:1973, 4.2.
3.6 Other terms and definitions
3.6.1
manufacturing lot
lot established by agreement between the customer and the supplier
3.6.2
orientation flat
OF
flat portion of wafer perimeter indicating the crystal orientation
Note 1 to entry: Generally, the orientation flat corresponds to the SAW propagation direction.
Note 2 to entry: Orientation flat is also referred to as the “primary flat” (see Figure 1).
Note 3 to entry: This note applies to the French language only.

– 14 – 62276 © IEC:2012
3.6.3
secondary flat
SF
flat portion of wafer perimeter shorter than the OF
Note 1 to entry: When present, the SF indicates wafer polarity and can serve to distinguish different wafer cuts.
Note 2 to entry: Secondary flat is also referred to as the “suborientation flat” (see Figure 1).
Note 3 to entry: This note applies to the French language only.
3.6.4
back surface roughness
roughness which scatters and suppresses bulk wave spurious at back surface
3.6.5
surface orientation
crystallographic orientation of the axis perpendicular to the surface of wafer
3.6.6
description of orientation and SAW propagation
indication of the surface orientation and the SAW propagation direction, separated by the
symbol “-“
Note 1 to entry: Specification of a 0° orientation is normally omitted.
Note 2: Typical examples for these expressions are shown in Table 1.
Table 1 – Description of wafer orientations
Material LT LN LT Quartz crystal LBO LGS
Quartz
Expression 128° Y-X X-112° Y ST-X 45° X-Z yxlt/48,5°/26,6°
Y-Z 36° Y-X
64° Y-X
3.6.7
ST-cut
cut direction of quartz to achieve zero temperature coefficient
3.6.8
tolerance of surface orientation
acceptable difference between specified surface orientation and measured orientation,
measured by X-ray diffraction
3.6.9
bevel
slope or rounding of the wafer perimeter
Note 1 to entry: Bevel is also referred to as “edge profile”.
Note 2 to entry: The process of creating a bevel is called “bevelling” or “edge rounding”.
Note 3 to entry: The profile and its tolerances should be specified by the supplier.
3.6.10
diameter of wafer
diameter of circular portion of wafer excluding the OF and SF regions

62276 © IEC:2012 – 15 –
3.6.11
wafer thickness
thickness measured at the centre of the wafer
4 Requirements
4.1 Material specification
4.1.1 Synthetic quartz crystal
A synthetic quartz crystal grown from Z-cut seed shall have an orientation within +5° of arc,
and the wafer should consist of excepting –X growth region. The quality of a synthetic quartz
crystal conforms to or exceeds the following grades in accordance with IEC 60758.
– Infrared absorption coefficient α value Grade D
– Inclusion density (pieces/cm ) Grade II
– Etch channel density (pieces/cm ) Grade 2
4.1.2 LN
LN is a single domain material having a Curie temperature within the specified range.
4.1.3 LT
LT is a single domain material having a Curie temperature or lattice constant within the
specified range.
4.1.4 LBO, LGS
Material not including twins.
4.2 Wafer specifications
4.2.1 General
The specifications listed in 4.2 apply in the absence of superseding agreements between user
and supplier. These specifications are expected to evolve and change as existing processes
are refined and new ones are developed. For wafers that are typically used in conjunction with
a photolithographic stepper equipment, LTV is typically specified as one of the flatness
criteria. When using projection lithography for full wafer exposure, FPD is often more relevant
than TTV, as the system will perform a tilt correction referenced off the front surface. Sori is
often more meaningful than warp since the least-squares derived reference plane used in that
measurement typically provides a more accurate representation of the wafer surface.
4.2.2 Diameters and tolerances
76,2 mm ± 0,25 mm (commonly referred to as a “3 inch” wafer)
100,0 mm ± 0,5 mm
125,0 mm ± 0,5 mm
150,0 mm ± 0,5 mm
4.2.3 Thickness and tolerance
Thickness tolerance is 0,18 mm to 0,80 mm. Tolerance for diameter of up to 100 mm is
± 0,03 mm. For diameter greater than 100 mm, thickness tolerance is to be agreed between
the buyer and the manufacturer.

– 16 – 62276 © IEC:2012
4.2.4 Orientation flat
a) Dimensions of OF and tolerances
22,0 mm ± 3,0 mm (for a 76,2 mm wafer)
32,5 mm ± 3,0 mm (for a 100 mm wafer)
42,5 mm ± 3,0 mm (for a 125 mm wafer)
47,5 mm ± 3,0 mm (for a 150 mm wafer)
57,5 mm ± 3,0 mm (for a 150 mm wafer)
b) Orientation tolerance
Orientation tolerance: ± 30’
Orientation of the OF shall be perpendicular to SAW propagation unless otherwise agreed
upon by the user and the supplier. Orientation of the OF for quartz crystal wafers is X-
plane (1 1-2 1) and an arrow pointing from the wafer centre to the OF is in the –X direction.
4.2.5 Secondary flat
The dimensions and tolerances are as listed below:
a) Dimensions of SF and tolerances
Dimensions and these tolerances of the SF are specified as reference values.
11,2 mm ± 4 mm unless otherwise agreed upon (for 76,2 mm wafer)
18,0 mm ± 4 mm unless otherwise agreed upon (for 100 mm wafer)
27,5 mm ± 4 mm unless otherwise agreed upon (for 125 mm wafer)
37,5 mm ± 4,5 mm unless otherwise agreed upon (for 150 mm wafer)
b) Orientation tolerance of SF
Orientation tolerance of the SF are measured with respect to the OF and are agreed on by
the user and the supplier with a typical value being ± 1,0°.
Laser marking can be used as an alternative method to indicate the front surface.
4.2.6 Back surface roughness
As agreed upon by the user and the supplier (see Table 2).
4.2.7 Warp
As specified in Table 2.
4.2.8 TV5 or TTV
As specified in Table 2.
62276 © IEC:2012 – 17 –
Table 2 – Roughness, warp, TV5 and TTV specification limits
Material Diameter of wafer Roughness of Warp TV5 TTV
back surface specified specified specified
value value value
(Ra)
μm μm μm
0,5 μm or greater 30 10 10
76,2 mm (3 inch)
Less than 0,5 μm 20 10 10
Quartz crystal
0,5 μm or greater 40 10 10
100 mm
Less than 0,5 μm 30 10 10
2,0 μm or greater 50 15 15
76,2 mm (3 inch) 2,0 μm to 0,5 μm 40 15 15
Less than 0,5 μm 40 10 10
2,0 μm or greater 50 20 20
100 mm 2,0 μm to 0,5 μm 40 15 15
Less than 0,5 μm 40 10 10
LN, LT
2,0 μm or greater 60 20 20
125 mm 2,0 μm to 0,5 μm 50 15 15
Less than 0,5 μm 40 10 10
2,0 μm or greater 60 20 20
150 mm 2,0 μm to 0,5 μm 50 15 15
Less than 0,5 μm 40 10 10
0,5 μm or greater 40 15 15
76,2 mm (3 inch)
Less than 0,5 μm 40 10 15
LBO
0,5 μm or greater 40 10 10
100 mm
Less than 0,5 μm 40 10 10
0,5 μm or greater 40 15 15
76,2 mm (3 inch)
Less than 0,5 μm 40 10 10
LGS
0,5 μm or greater 40 20 20
100 mm
Less than 0,5 μm 40 10 10
4.2.9 Front (propagation) surface finish
The front surface shall be mirror polished. Surface finishing details are subject to agreement
between the user and the supplier.
4.2.10 Front surface defects
a) Scratches
No scratches by visual inspection
b) Chips
1) Edge chips:
Radial depth: less than 0,5 mm
Peripheral chord length: less than 1,0 mm
2) Surface:
No chips by visual inspection
– 18 – 62276 © IEC:2012
c) Cracks
No cracks by visual inspection
d) Contamination
No contamination by visual inspection
e) Others
Other defects such as dimples, pits, and orange peel: no such defects by visual inspection.
4.2.11 Surface orientation tolerance
Surface orientation shall be specified by the user and the supplier.
Quartz crystal: ± 10’
LN, LT, LBO: ± 20’
LGS crystal: ± 10’
4.2.12 Inclusions
LN/LT/LBO/LGS: No visible inclusions by naked eye inspection.
Synthetic quartz: material satisfies the specification Grade II of IEC 60758:2008, 4.1.2.
4.2.13 Etch channel density and position of seed for quartz wafer
The etch channel density and the position of the seed are described below:
a) Etch channel within seed portion for a quartz crystal wafer
The density of the etch channel in a state of not passing through from front surface to
back surface is less than 36 as per 76,2 mm wafer or less than 47 as per 100 mm wafer.
b) Position of seed
The seed shall be included within ± 3,5 mm centre width of the Z’ direction and parallel to
the X-direction of the centre of the wafer.
4.2.14 Bevel
The bevel shall be as agreed upon by the user and the supplier.
4.2.15 Curie temperature and tolerance
NOTE Only applies to LN/LT. The centre value for the specification is as agreed upon by the user and the
supplier. Alternatively, the lattice constant can be specified.
LN: centre value within 1 133 °C and 1 145 °C. Tolerance ± 3 °C
LT: centre value within 598 °C and 608 °C. Tolerance ± 3 °C
4.2.16 Lattice constant
NOTE Alternatively, the Curie temperature can be specified.
LT: 0,515 39 nm ± 0,000 02 nm for an axis measured at 25 °C
4.2.17 Bulk resistivity (conductivity) for reduced LN and LT
8 12 -12 -8
LN: 1,0 x 10 Ω·cm <B.R.<1,0 x 10 Ω·cm (1,0 x 10 Ω/cm 10 13 -13 -10
LT: 1,0 x 10 Ω·cm <B.R.<1,0 x 10 Ω·cm (1,0 x 10 Ω/cm
62276 © IEC:2012 – 19 –
5 Sampling plan
A statistically significant sampling plan shall be agreed upon by the user and the supplier.
Sampled wafers shall be randomly selected and representative of the production population,
and shall satisfy the quality assurance criteria using the prescribed test methods.
5.1 Sampling
Unless otherwise specified, sampling shall be in accordance with AQL 2,5 %, single sampling
as defined in IEC 60410. The specified AQL applies to the listed groups of defects considered
collectively.
5.2 Sampling frequency
Appropriate statistical methods shall be applied to determine adequate sample size and
acceptance criteria for the considered lot size. In the absence of more detailed statistical
analysis, the following sampling plan can be employed:
a) Dimensions
Diameter 2 wafers/manufacturing
...