SIST EN 60749-35:2007

• Abstract:

  Defines the procedures for performing acoustic microscopy on plastic encapsulated electronic components. Provides a guide to the use of acoustic microscopy for detecting anomalies (delamination, cracks, mould-compound voids, etc.) reproducibly and non-destructively in plastic packages.

• Status: Published
• Publication Date: 31-Dec-2006
• ICS: 31.080.01 - Semiconductor devices in general
• Technical Committee: I11 - Imaginarni 11
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-2007
• Due Date: 01-Jan-2007
• Completion Date: 01-Jan-2007
• Ref Project: EN 60749-35:2006 - Semiconductor devices - Mechanical and climatic test methods - Part 35: Acoustic microscopy for plastic encapsulated electronic components

• Referred By: SIST EN 60749-20:2010 - Semiconductor devices - Mechanical and climatic test methods - Part 20: Resistance of plastic encapsulated SMDs to the combined effect of moisture and soldering heat (IEC 60749-20:2008)
• Effective Date: 03-Feb-2026
• Referred By: SIST EN IEC 60749-20:2020 - Semiconductor devices - Mechanical and climatic test methods - Part 20: Resistance of plastic encapsulated SMDs to the combined effect of moisture and soldering heat
• Effective Date: 03-Feb-2026
• Referred By: SIST EN 62047-4:2010 - Semiconductor devices - Micro-electromechanical devices - Part 4: Generic specification for MEMS (IEC 62047-4:2008)
• Effective Date: 03-Feb-2026

SIST EN 60749-35:2007 is a CENELEC European Standard published by SIST for semiconductor devices. It specifies how to perform acoustic microscopy on plastic encapsulated electronic components so that delamination, cracks, mould-compound voids, and similar anomalies can be found reproducibly and non-destructively.

The document is aimed at users who need a repeatable inspection method for plastic packages and a way to record what was scanned, how it was scanned, and what was seen. It is part of the IEC 60749 series on mechanical and climatic test methods for semiconductor devices.

What does SIST EN 60749-35:2007 specify?

SIST EN 60749-35:2007 specifies procedures for acoustic microscopy on plastic encapsulated electronic components. It describes the test apparatus, the setup steps, the scan procedure, and the way results should be checked and recorded.

The standard is organized into four main clauses and four informative annexes.

Annex	What it covers
Annex A	Acoustic microscopy check sheet, with example scan records and delamination types I to VIII
Annex B	Potential image pitfalls and common causes of misleading indications
Annex C	Some limitations of acoustic microscopy
Annex D	Reference checklist for presenting applicable scanned data

In practice, this means the standard is not only about taking images. It also tells the user how to prepare the equipment, how to judge whether an indication is a real package defect or an imaging artefact, and what data should be kept with the scan record.

What are the key requirements of SIST EN 60749-35:2007?

SIST EN 60749-35:2007 focuses on setup, scanning discipline, interpretation, and documentation. The most important requirements are in Clauses 3 and 4.

Equipment setup and alignment

The standard requires a suitable acoustic microscope system, either reflective or through transmission. A reflective system uses one transducer as both pulser and receiver, while a through transmission system uses separate sending and receiving transducers.

The transducer should be chosen with the highest usable ultrasonic frequency, but still low enough to give a clear signal from the interface of interest. This matters because higher frequency improves detail, while lower frequency may be needed for thicker packages or through transmission work.

The sample must be placed so its upper surface is parallel to the scan plane, and air bubbles must be removed from the unit surface and transducer head. The transducer must also be perpendicular to the sample surface. These steps matter because tilt, bubbles, and poor coupling can create false indications or hide defects.

Focusing and verification

Focus is set by maximizing the reflected amplitude in the A-mode display at the interface being imaged. The setup should be verified with reference packages or standards, including packages with and without delamination.

In practice, this means the operator should prove that the chosen settings can show the defect level expected at the interface of interest before relying on production or qualification results.

Scanning and inspection

The scan procedure requires inspection of acoustic images for anomalies, then confirmation that each anomaly is a real package defect rather than an artefact of the imaging process. The standard recommends checking the A-mode display at the anomaly location, and physical analysis may also be needed.

Through transmission mode is described as a quick scan method for finding large defects before detailed C-mode investigation. This is useful when screening a lot of parts, because it can point the operator to components that need a closer look.

Evaluation and records

The final evaluation is done against the failure criteria in the relevant specification. The standard also requires recording the images and the final instrument setup parameters.

This matters in practice because acoustic microscopy is only useful when results can be traced back to the exact setup, scan area, transducer settings, and image interpretation used for the decision.

What terms does SIST EN 60749-35:2007 define?

SIST EN 60749-35:2007 defines several terms that matter for reading and using the method correctly.

• A-mode - acoustic data collected at the smallest X-Y-Z region; in this standard it is mainly used for focusing.
• B-mode - acoustic data collected along an X-Z or Y-Z plane versus depth; it gives a cross-sectional view along a scan line.
• C-mode - acoustic data collected in an X-Y plane at a selected depth; it is the preferred mode for scanning devices to determine compliance to IEC 60749-20.
• Reflective acoustic microscope - a microscope that uses one transducer for both pulsing and receiving, also called a pulse/echo system.
• Through transmission mode - acoustic data collected through the full depth of the sample using a sending transducer and a receiving transducer on opposite sides.
• Time-of-flight (TOF) - the travel time of the acoustic pulse to and from the interface in reflective mode, or through the sample in through transmission mode.
• Focal length (FL) - the distance in water where the transducer spot size is smallest.

Knowing these terms helps the reader understand what the operator is looking at on the display and why one mode is chosen over another.

Who uses SIST EN 60749-35:2007?

SIST EN 60749-35:2007 is used by semiconductor device manufacturers, reliability and failure-analysis laboratories, and quality assurance teams working with plastic encapsulated electronic components. It is also relevant to buyers and inspectors who need a non-destructive way to check package integrity.

Typical tasks include setup of acoustic microscopes, inspection for delamination or cracks, comparison against acceptance criteria in a product specification, and preparation of inspection records for lot release or engineering analysis.

What changed in SIST EN 60749-35:2007 from the previous edition?

SIST EN 60749-35:2007 is the first edition of IEC 60749-35 and it cancels and replaces IEC/PAS 62191 published in 2000. The document states that this edition is a technical revision and that the European adoption was made without modification.

Which standards are used with SIST EN 60749-35:2007?

SIST EN 60749-35:2007 is part of the IEC 60749 series on semiconductor device mechanical and climatic test methods. The document specifically notes IEC 60749-20 in connection with C-mode scanning and in the bibliography.

For users, this means Part 35 is best read as a companion method inside a broader family of semiconductor test standards, with IEC 60749-20 being a related reference when assessing resistance of plastic-encapsulated surface mount devices to moisture and soldering heat.

What does the SIST EN 60749-35:2007 document contain?

SIST EN 60749-35:2007 contains clause text, figures showing A-mode, B-mode, C-mode, through transmission display, and diagrams of reflective and through transmission microscope systems. It also contains four informative annexes that are practical for daily use.

Annex A provides a check sheet with active and non-active circuit side scan records and delamination types I to VIII. Annex B lists common image pitfalls such as false delamination, loss of signal, phase cancellation, and sample tilt. Annex C explains practical limitations such as depth-related attenuation, axial and lateral resolution limits, irregular package geometry, and edge effects. Annex D lists the scan setup and reporting items that should be captured, including transducer data, scan area, gain settings, gating, sample orientation, and image file information.

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EUROPEAN STANDARD
EN 60749-35
NORME EUROPÉENNE
September 2006
EUROPÄISCHE NORM
ICS 31.080.01
English version
Semiconductor devices -
Mechanical and climatic test methods
Part 35: Acoustic microscopy for plastic encapsulated
electronic components
(IEC 60749-35:2006)
Dispositifs à semiconducteurs -  Halbleiterbauelemente -
Méthodes d'essais mécaniques Mechanische und klimatische
et climatiques Prüfverfahren
Partie 35: Microscopie acoustique Teil 35: Ultraschallmikroskopie
pour composants électroniques für kunststoffverkappte Bauelemente
à boîtier plastique der Elektronik
(CEI 60749-35:2006) (IEC 60749-35:2006)

This European Standard was approved by CENELEC on 2006-09-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60749-35:2006 E
Foreword
The text of document 47/1863/FDIS, future edition 1 of IEC 60749-35, prepared by IEC TC 47,
Semiconductor devices, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 60749-35 on 2006-09-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2007-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2009-09-01
__________
Endorsement notice
The text of the International Standard IEC 60749-35:2006 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60749-20 NOTE  Harmonized as EN 60749-20:2003 (not modified).
__________
NORME CEI
INTERNATIONALE
IEC
60749-35
INTERNATIONAL
Première édition
STANDARD
First edition
2006-07
Dispositifs à semiconducteurs – Méthodes
d’essais mécaniques et climatiques –
Partie 35:
Microscopie acoustique pour composants
électroniques à boîtier plastique

Semiconductor devices – Mechanical and
climatic test methods –
Part 35:
Acoustic microscopy for plastic encapsulated
electronic components
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Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
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60749-35  IEC:2006 – 3 –
CONTENTS
FOREWORD.5

1 Scope.11
2 Terms and definitions .11
3 Test apparatus .19
3.1 Reflective acoustic microscope system.19
3.2 Through transmission acoustic microscope system.19
3.3 Reference packages or standards .19
3.4 Sample holder .19
4 Procedure .21
4.1 General .21
4.2 Equipment setup .21
4.3 Performance of acoustic scans.21

Annex A (informative) Acoustic microscopy check sheet (example only – not a
mandatory template) .25
Annex B (informative) Potential image pitfalls .35
Annex C (informative) Some limitations of acoustic microscopy .37
Annex D (informative) Reference checklist for presenting applicable scanned data.39

Bibliography.43

Figure 1 – Example of A-mode display.11
Figure 2 – Example of B-mode display (bottom half of picture on left) .13
Figure 3 – Example of C-mode display.13
Figure 4 – Example of through transmission display.15
Figure 5 – Diagram of a reflective acoustic microscope system.17
Figure 6 – Diagram of a through transmission acoustic microscope system .17

60749-35  IEC:2006 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SEMICONDUCTOR DEVICES –
MECHANICAL AND CLIMATIC TEST METHODS –

Part 35: Acoustic microscopy for plastic encapsulated
electronic components
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
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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 60749-35 has been prepared by IEC technical committee 47:
Semiconductor devices.
This first edition cancels and replaces IEC/PAS 62191 published in 2000, which was based on
a Joint (IPC/JEDEC) Industry Standard. This edition constitutes a technical revision.

60749-35  IEC:2006 – 7 –
The text of this standard is based on the following documents:
FDIS Report on voting
47/1863/FDIS 47/1877/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.
IEC 60749 consists of the following parts, under the general title Semiconductor devices –
Mechanical and climatic test methods:
Part 1: General
Part 2: Low air pressure
Part 3: External visual inspection
Part 4: Damp heat, steady state, highly accelerated stress test (HAST)
Part 5: Steady-state temperature humidity bias life test
Part 6: Storage at high temperature
Part 7: Internal moisture content measurement and the analysis of other residual gases
Part 8: Sealing
Part 9: Permanence of marking
Part 10: Mechanical shock
Part 11: Rapid change of temperature – Two-fluid-bath method
Part 12: Vibration, variable frequency
Part 13: Salt atmosphere
Part 14: Robustness of terminations
Part 15: Resistance to soldering temperature for through-hole mounted devices
Part 16: Particle impact noise detection (PIND)
Part 17: Neutron irradiation
Part 18: Ionizing radiation (total dose)
Part 19: Die shear strength
Part 20: Resistance of plastic-encapsulated SMDs to the combined effect of moisture and
soldering heat
Part 21: Solderability
Part 22: Bond strength
Part 23: High temperature operating life
Part 24: Accelerated moisture resistance – Unbiased HAST
Part 25: Temperature cycling
Part 26: Electrostatic discharge (ESD) sensitivity testing – Human body model (HBM)
Part 27: Electrostatic discharge (ESD) sensitivity testing – Machine model (MM)

60749-35  IEC:2006 – 9 –
Part 28: Electrostatic discharge (ESD) sensitivity testing – Charged device model (CDM)
(under consideration)
Part 29: Latch-up test
Part 30: Preconditioning of non-hermetic surface mount devices prior to reliability testing
Part 31: Flammability of plastic-encapsulated devices (internally induced)
Part 32: Flammability of plastic-encapsulated devices (externally induced)
Part 33: Accelerated moisture resistance – Unbiased autoclave
Part 34: Power cycling
Part 35: Acoustic microscopy for plastic encapsulated electronic components
Part 36: Acceleration, steady state
Part 37: Board level drop test method of components for handheld electronic products (to
be published)
Part 38: Soft error rate testing of electronic components (under consideration)
Part 39: Measurement of moisture diffusivity and water solubility in organic materials used
for semiconductor components (to be published)
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result 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.
60749-35  IEC:2006 – 11 –
SEMICONDUCTOR DEVICES –
MECHANICAL AND CLIMATIC TEST METHODS –

Part 35: Acoustic microscopy for plastic encapsulated
electronic components
1 Scope
This part of IEC 60749 defines the procedures for performing acoustic microscopy on plastic
encapsulated electronic components. This standard provides a guide to the use of acoustic
microscopy for detecting anomalies (delamination, cracks, mould-compound voids, etc.)
reproducibly and non-destructively in plastic packages.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
A-mode
acoustic data collected at the smallest X-Y-Z region defined by the limitations of the given
acoustic microscope
NOTE An A-mode display contains amplitude and phase/polarity information as a function of time of flight at a
single point in the X-Y plane. In this test method, A-mode is primarily used for focussing the acoustic microscope.
See Figure 1.
Time
IEC  1333/06
Figure 1 – Example of A-mode display
2.2
B-mode
acoustic data collected along an X-Z or Y-Z plane versus depth using a reflective acoustic
microscope. A B-mode scan contains amplitude and phase/polarity information as a function
of time of flight at each point along the scan line
NOTE A B-mode scan furnishes a two-dimensional (cross-sectional) description along a scan line (X or Y). In this
test method B-mode is used to provide cross-sectional acoustic information. When scanned, B-mode can be used
to track the depth of a defect. See Figure 2.
Amplitude
60749-35  IEC:2006 – 13 –
C-mode
display
Line of
B-mode
scan
B-mode
display
IEC  1334/06
Figure 2 – Example of B-mode display (bottom half of picture on left)
2.3
back-side substrate view area
interface between the encapsulant and the back of the substrate within the outer edges of the
substrate surface (refer to Annex A, type IV)
2.4
C-mode
acoustic data collected in an X-Y plane at depth (Z) using a reflective acoustic microscope
NOTE 1 A C-mode scan contains amplitude and phase/polarity information at each point in the scan plane. A C-
mode scan furnishes a two-dimensional (area) image of echoes arising from reflections at a particular depth (Z).
See Figure 3.
NOTE 2 C-mode is the preferred mode for scanning devices to determine compliance to the criteria of
IEC 60749-20.
IEC  1335/06
Figure 3 – Example of C-mode display

60749-35  IEC:2006 – 15 –
2.5
through transmission mode
acoustic data collected in an X-Y plane throughout the depth (Z) using a through transmission
acoustic microscope
NOTE A through transmission mode scan contains only amplitude information at each point in the scan plane. A
th
...