IEC PAS 60191-6-19:2008

IEC/PAS 60191-6-19
Edition 1.0 2008-01
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Mechanical standardization of semiconductor devices –
Part 6-19: Measurement methods of package warpage at elevated temperature
and the maximum permissible warpage

IEC/PAS 60191-6-19:2008(E)
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IEC/PAS 60191-6-19
Edition 1.0 2008-01
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Mechanical standardization of semiconductor devices –
Part 6-19: Measurement methods of package warpage at elevated temperature
and the maximum permissible warpage

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS : 31.080.01 ISBN 2-8318-9527-8

– 2 – PAS 60191-6-19 © IEC:2008(E)

CONTENTS
FOREWORD.3

1 Scope.5

2 Normative references .5

3 Terms and definitions .5

4 Sample.9

4.1 Sample size .9

4.2 Solder ball removal .9

4.3 Pre-treatment conditions .9
4.4 Maximum time after pretreatment until measurement.9
4.5 Repetition of the reflow cycles for the sample.9
5 Measurement .9
5.1 General description .9
5.2 Temperature profile and the temperatures for measurements .9
5.3 Measurement method.10
6 Maximum permissible package warpage at elevated temperature .11
7 Recommended datasheet for the package warpage.11
7.1 Measurement temperatures for data sheet .11
7.2 Data sheet.11
7.3 Example of data sheets .12

Annex A (informative) Explanatory notes .14
Bibliography.22

Figure 1 – Measuring zone of BGA and FBGA in full grid layout.6
Figure 2 – Measuring zone of BGA and FBGA perimeter layout with 4 rows and 4
columns .6
Figure 3 – Measuring zone of FLGA perimeter layout with 4 rows and 4 columns.7
Figure 4 – Calculation of the sign of package warpage .8
Figure 5 – Package warpage .8
Figure 6 – Thermocouple placement .10
Figure 7 – Temperature dependency of the package warpage .12

Figure 8 – Recommended data sheet.13
Figure A.1 – Calculation of maximum relative displacement immmune from open solder
joints.16
Figure A.2 – Calculation of maximum relative displacement immmune from solder ball
bridges .17
Figure A.3 – Package warpage of FLGA at elevated temperature.19

Table 1 – Maximum permissible package warpages for BGA and FBGA.11
Table 2 – Maximum permissible package warpages for FLGA.11
Table A.1 – Maximum permissible package warpage for BGA and FBGA – Explanatory
table .18
Table A.2 – Maximum permissible package warpage for FLGA – Explanatory table .19
Table A.3 – Comparison between JESD22B112 and IEC/JEITA PAS 60191-6-19 .20

PAS 60191-6-19 © IEC:2008(E) – 3 –

INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
MECHANICAL STANDARDIZATION OF SEMICONDUCTOR DEVICES –

Part 6-19: Measurement methods of package warpage at elevated

temperature and the maximum permissible warpage

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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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.

A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 60191-6-19 was submitted by the JEITA (Japan Electronics and Information
Technology Industries Association) and has been processed by IEC subcommittee SC47D:
Mechanical standardization for semiconductor devices.
The text of this PAS is based on This PAS was approved for
the following documents publication by the P-members of the
committee concerned as indicated in
the following document:
Draft PAS Report on voting
47D/691/NP 47D/707/RVN
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.

– 4 – PAS 60191-6-19 © IEC:2008(E)

This PAS shall remain valid for an initial maximum period of three years starting from the

publication date. The validity may be extended for a single three-year period, following which

it shall be revised to become another type of normative document or shall be withdrawn.

PAS 60191-6-19 © IEC:2008(E) – 5 –

MECHANICAL STANDARDIZATION OF SEMICONDUCTOR DEVICES –

Part 6-19: Measurement methods of package warpage at elevated

temperature and the maximum permissible warpage

1 Scope
This PAS stipulates the package warpage criteria and the package warpage measurement

methods at elevated temperature for BGA, FBGA, and FLGA

2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document applies.
JEITA EDR-4701/301, Resistance to soldering heat for surface mounting devices (SMD)

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
measuring zone
area to be measured to determine the package warpage
NOTE 1 For the packages whose stand-off height is more than 0,1 mm, such as BGA and FBGA, the measuring
zone is the area where terminals are located. This area is bordered by the lines connecting the centers of the
outermost neighboring solder balls (see Figure 1 and Figure 2). If there are thermal balls at the package centre,
their area is also considered as a part of the measuring zone
NOTE 2 For the packages whose stand-off height is 0,1 mm or less, such as FLGA, the measuring area is the
substrate surface except certain edge margin (see Figure 3, dimension L). The width of this margin L depends on
the capability of each measuring instrument (0,2 mm recommended).

– 6 – PAS 60191-6-19 © IEC:2008(E)

NOTE The hatched area indicates the measuring zone.
Figure 1 – Measuring zone of BGA and FBGA in full grid layout

Figure 2 – Measuring zone of BGA and FBGA perimeter layout
with 4 rows and 4 columns
PAS 60191-6-19 © IEC:2008(E) – 7 –

NOTE The edge margin L indicates the exempt area from measurement to avoid measurement noise depending
on the instrument capability. Recommended edge margin L = 0,2 mm.
Figure 3 – Measuring zone of FLGA perimeter layout with 4 rows and 4 columns
3.2
convex warpage
arched top surface (not interconnect side) of package being mounted on PWB
NOTE The sign of the convex warpage is defined as plus.
3.3
concave warpage
inward-curving top surface (not interconnect side) of package being mounted on PWB
NOTE The sign of the concave warpage is defined as minus.
3.4
package warpage sign
plus or minus sign of package warpage determined by the sign of the sum of the largest
positive displacement and the largest negative displacement of the package profile on both

measurement zone diagonals
NOTE These diagonals are regarded as base lines connecting the outermost opposite corners of the measuring
zone. The sign of the package warpage is defined as the sign of:
(AB +AB +CD +CD )
MAX MIN MAX MIN
AB is the largest positive displacement and AB is the largest negative displacement of the package profile on
MAX MIN
the diagonal AB; (The sign of AB is plus and AB is zero in Figure 4.)
MAX MIN
CD is the largest positive displacement and CD is the largest negative displacement of the package profile on
MAX MIN
the diagonal CD; (The sign of CD is plus and that of CD is minus in Figure 4.)
MAX MIN
The concave or convex impression of the package warpage can differ from the above defined sign, in critical cases.

– 8 – PAS 60191-6-19 © IEC:2008(E)

Measuring zone
CD
MAX
D
CD
MIN
Package
Measuring zone diagonal
A
B
Depopulated
zone
Package warpage profile
C
Measuring zone diagonal
AB
MAX
Base line
AB =0
MIN
Measuring zone diagonal
Measuring zone diagonal
Figure 4 – Calculation of the sign of package warpage
3.5
package warpage
difference of the largest positive and the largest negative displacements of the package
warpage in the measuring zone with respect to the reference plane, preceded by package
warpage sign
NOTE This reference plane is derived using the least square method with the measuring zone data. For example,
the absolute value of the package warpage ⏐C⏐ is obtained by the sum of the absolute value of the largest positive
displacement ⏐A⏐ and that of the largest negative displacement ⏐B⏐. This is in respect to the reference plane
which is derived by using the least square method, as shown in Figure 5. Package warpage sign precedes ⏐C⏐.
C = A + B
Convex
Concave
A A
Reference Reference
B
plane
plane
B
Measuring zone
Measuring zone
Figure 5 – Package warpage
PAS 60191-6-19 © IEC:2008(E) – 9 –

4 Sample
4.1 Sample size
At least three samples are required for each measurement condition.

4.2 Solder ball removal
If the measurement method of the package warpage requires the elimination of the solder
balls from a package, it is recommended to use mechanical removal rather than hot reflow. If
the samples are prepared without solder balls for the convenience of the measurement, the

package shall be subjected to the thermal history of the solder ball attachment process.
4.3 Pre-treatment conditions
The bake and moisture soak conditions shall conform to the moisture sensitivity level
specified in JEITA ED-4701/301. The peak temperature of the package warpage
measurement shall meet the specification of the product.
4.4 Maximum time after pretreatment until measurement
It is recommended to measure the warpage no longer than 5 h after the pretreatment.
4.5 Repetition of the reflow cycles for the sample
The same sample shall not be subjected to the repetition of the reflow cycles. The sample can
only be subjected to more than one cycle of reflow for remeasurement, if reproducibility of test
data was evaluated prior to the test.
5 Measurement
5.1 General description
The package warpage is measured by “shadow moiré method” or “laser reflection method”.
Samples are subjected to heating and cooling while measuring the package warpage at the
temperatures specified in 5.2. The measurement points shall not be on the crown of solder
balls but on the substrate surface of the package. Only when the behaviour of the top surface
of the package (mostly marking surface) is verified to coincide with that of the substrate
surface, the measurement on the top surface is allowed.

5.2 Temperature profile and the temperatures for measurements
5.2.1 The temperature profile for the warpage measurement does not necessarily simulate
that for production. Higher priorities are placed on
– maintaining the temperature constant during the measurement,
– never exposing the samples more than necessary duration at high temperature. Samples
shall be proceeded to the next measurement as soon as possible,
– avoiding a temperature surge to prevent the overshoot, and
– Minimizing the temperature difference between the top and bottom surfaces.
5.2.2 The temperatures for measurements are as follows:
– room temperature;
– melting point;
– 10 – PAS 60191-6-19 © IEC:2008(E)

– peak temperature;
– solidification point;
– room temperature after cool down.

The melting point and the solidification point are 220 °C for Sn-3.0Ag-0,5Cu solder as a

reference. Other solder composites may take different temperatures. The peak temperature

basically conforms to the package classifications specified in JEITA ED-4701/301, but to be

exact, it shall follow the supplier’s recommended max temperature.

5.2.3 It is recommended that a thermocouple of gauge 30 (φ0,25 mm) or flat tip type be used.

5.2.4 The thermocouple is attached on the centre of the package body using either thermally
conductive epoxy or heat-resistant polyimide tape. When polyimide tape is used, thermally
conductive sheet shall be applied between the thermocouple bead and the package surface to
enhance thermal conductivity as a thermal interface material.
5.2.5 When a measuring instrument is being set up, the temperature of the molded side of
the package facing a heater is also measured. The temperature difference from the substrate
surface shall preferably be less than 10 °C by adjusting the heating mechanism and the
temperature profile.
Thermocouple on the
substrate side for
temperature profile control
(warpage measurement
Package
side)
Thermocouple on the
molded side for temporary
measurement of the
Heater side
temperature
Figure 6 – Thermocouple placement
5.3 Measurement method
5.3.1 Shadow moiré method
Solder balls shall be removed prior to the measurement on the substrate surface.
Measurements are conducted by placing the grating (low CTE glass with transparent and
opaque stripes) parallel to the sample. Then, the projection of light beam at an angle of

approximately 45° through the grating produces the stripe pattern on the sample. Observation
of the stripe pattern through the grating results in the moiré fringe pattern (geometric
interference pattern). Image processing and the analysis of the patterns provide the
displacement from planarity over the substrate surface. The instrument is capable of setting
the measuring zone and measuring the warpage at elevated temperatures including the peak
temperature.
5.3.2 Laser reflection method
Solder balls shall be removed when the solder ball pitch is not large enough for the laser
beam to measure the warpage on the substrate surface. Samples are placed on the
measurement table. The displacement from the flatness is measured by the laser
displacement sensor. The warpage is generally measured by scanning the laser beam over
the terminal lands or between balls throughout the measuring zone. The grid pitch of the
measurement points is preferably less than the solder ball pitch. The instrument is capable of
setting the measuring zone and measuring the warpage at elevated temperatures including
the peak temperature.
PAS 60191-6-19 © IEC:2008(E) – 11 –

5.3.3 Data analysis (data table, diagonal scan graph, 3D plot graph)

The magnitude of the warpage is obtained from the data table of the measurements or 3D plot

graph (warpage distribution diagram over the measuring zone). The sign of the warpage

(warpage direction) is then determined from the diagonal scan graph and precedes the value.

6 Maximum permissible package warpage at elevated temperature

The criteria for maximum permissible package warpages (absolute values) for BGA and FBGA

are specified in Table 1, and those for FLGA are specified in Table 2.

Table 1 – Maximum permissible package warpages for BGA and FBGA
Dimensions in millimetres
Solder ball pitch 0,4 0,5 0,65 0,8 1,0 1,27
Condition of ball height 0,20 0,25 0,33 0,35 0,40 0,50 0,60
Maximum permissible package warpage 0,10 0,11 0,14 0,17 0,17 0,22 0,25

(absolute value)
Table 2 – Maximum permissible package warpages for FLGA
Dimensions in millimetres
Land pitch 0,4 0,5 0,65 0,8
Condition of thickness of molten solder paste 0,08 0,10 0,11 0,13
Maximum permissible package warpage 0,08 0.10 0,11 0,13
(absolute value)
7 Recommended datasheet for the package warpage
7.1 Measurement temperatures for data sheet
Typical measurement temperatures for data sheet are room temperature, melting point, peak
temperature, solidification point and room temperature after cooling.
7.2 Data sheet
The data sheet is composed of
– temperature dependency of the package warpage (see Figure 7),
– surface topography at each temperature in 3D plots (optional),
NOTE 1 If the sign of warpage is opposite, explanation is required; see Figure 8.
– diagonal profile of the package at each temperature (optional),
NOTE 2 If the sign of warpage is opposite, explanation is required; see Figure 8.
– explanatory figure of the sign of the package warpage (optional),
– temperature profile for measurement,

– 12 – PAS 60191-6-19 © IEC:2008(E)

7.3 Example of data sheets
+
+/- Sign
Average warpage
for xxxx & yyyy
-
-10
-20
-30
-40
-50
-60
-70
25C 150C 220C 260C 220C 150C 25C
xxxxAVG -17.8 -46 -55.7 -44 -47 -33.8 -18.3
-21.5 -46.2 -58.7 -51.8 -48.5 -32 -21.8
yyyyAVG
Figure 7 – Temperature dependency of the package warpage

Warpage(um)
PAS 60191-6-19 © IEC:2008(E) – 13 –

Room
temperature
（150 °C）
（Preheat
temperature,
for reference)
220 °C
Melting po
...