IEC PAS 62191:2000
(Main)Acoustic microscopy for nonhermetic encapsulated electronic components
Acoustic microscopy for nonhermetic encapsulated electronic components
Defines the procedures for performing acoustic microscopy on nonhermetic encapsulated electronic components. Provides users with an acoustic microscopy process flow for detecting anomalies (delamination, cracks, mold compounds voids, etc.) nondestructively in plastic packages while achieving reproducibility.
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Standards Content (Sample)
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Edition 1.0
2000-11
Acoustic microscopy for nonhermetic
encapsulated electronic components
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IN TER N A TION AL Reference number
E L E C T R OT E CHNI CA L
IEC/PAS 62191
C O MMI S S I O N
IPC/JEDEC J-STD-035
MAY 1999
JOINT
INDUSTRY
STANDARD
Acoustic Microscopy
for Nonhermetic
Encapsulated
Electronic
Components
NOTICE
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by the EIA General Counsel.
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The information included in EIA/JEDEC standards and publications represents a sound approach
to product specification and application, principally from the solid state device manufacturer
viewpoint. Within the JEDEC organization there are procedures whereby an EIA/JEDEC
No claims to be in conformance with this standard may be made unless all requirements stated in
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publication should be addressed to JEDEC Solid State Technology Association, 2500 Wilson
©
Arlington, VA 22201-3834
2500 Wilson Boulevard
Engineering Department
ELECTRONIC INDUSTRIES ALLIANCE 1999
Published by
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the standard are met.
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adopting the EIA/JEDEC standards or publications.
whether the standard is to be used either domestically or internationally.
Copyright © 1999, JEDEC; 2000, IEC
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
CAOUSTIC MICROSCOP Y FOR NONHE RMETIC E NCAPSULATED
ELECTRONIC COMPONENTS
FOREWORD
A PAS is a technical specification not fulfilling the requirements for a standard, but made available to the
public and established in an organization operating under given procedures.
IEC-PAS 62191 was submitted by JEDEC and has been processed by IEC technical committee 47: Semiconductor
devices.
The text of this PAS is based on the This PAS was approved for
following document: publication by the P-members of the
committee concerned as indicated in
the following document:
Draft PASReport on voting
47/1476/PAS 47/1512/RVD
Following publication of this PAS, the technical committee or subcommittee concerned will investigate the
possibility of transforming the PAS into an International Standard.
An IEC-PAS licence of copyright and assignment of copyright has been signed by the IEC and JEDEC and is
recorded at the Central Office.
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising all
national electrotechnical committees (IEC National Committees). The object of the 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, the IEC publishes International Standards. Their preparation is entrusted to technical committees;
any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International,
governmental and non-governmental organizations liaising with the IEC also participate in this preparation. The IEC
collaborates closely 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 the 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
National Committees.
3) The documents produced have the form of recommendations for international use and are published in the fo rm of
standards, technical specifications, technical reports or guides and they are accepted by the National Committees in
that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International Standards
transparently to the maximum extent possible in their national and regional standards. Any divergence between the
IEC Standard and the corresponding national or regional standard shall be clearly indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this PAS may be the subject of patent rights. The
IEC shall not be held responsible for identifying any or all such patent rights.
Copyright © 1999, JEDEC; 2000, IEC
ENCAPSULATED ELECTRONIC COMPONENTS
1 Scope
a scan line (X or Y). See Figure 2 - Example of B-mode Display.
point along the scan line. A B-mode scan furnishes a two-dimensional (cross-sectional) description along
B-mode scan contains amplitude and phase/polarity information as a function of time of flight at each
Acoustic data collected along an X-Z or Y-Z plane versus depth using a reflective acoustic microscope. A
2.2 B-mode
Figure 1 — Example of A-mode Display
of flight at a single point in the X-Y plane. See Figure 1 - Example of A-mode Display.
microscope. An A-mode display contains amplitude and phase/polarity information as a function of time
Acoustic data collected at the smallest X-Y-Z region defined by the limitations of the given acoustic
2.1 A-mode
2 Definitions
packages while achieving reproducibility.
detecting anomalies (delamination, cracks, mold compound voids, etc.) nondestructively in plastic
electronic components. This method provides users with an acoustic microscopy process flow for
This test method defines the procedures for performing acoustic microscopy on nonhermetic encapsulated
Test Methods for Packaged Devices an with the IPC.)
(From JEDEC Board Ballot JCB-98-99, under the cognizance of the JC-14.1 Committee on Reliability
ACOUSTIC MICROSCOPY FOR NONHERMETIC
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surface.
Figure 3 — Example of C-mode Display
Figure 3.
furnishes a two-dimensional (area) image of echoes arising from reflections at a particular depth (Z). See
scan contains amplitude and phase/polarity information at each point in the scan plane. A C-mode scan
Acoustic data collected in an X-Y plane at depth (Z) using a reflective acoustic microscope. A C-mode
2.4 C-mode
The interface between the encapsulant and the back of the substrate within the outer edges of the substrate
2.3 Back-Side Substrate View Area (Refer to Annex A, Type IV)
Figure 2 — Example of B-mode Display (bottom half of picture on left)
2.2 B-mode (cont’d)
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Copyright © 1999, JEDEC; 2000, IEC
substrate.
bond/stitch bond region of the innermost portion of the L/F.)
The imaged area which extends from the outer L/F edges of the package to the L/F “tips” (wedge
2.10 Leadframe (L/F) View Area (Refer to Annex A, Type V)
The X-Y plane at a depth (Z), which the amplitude of the acoustic signal is maximized.
2.9 Focus Plane
The distance in water at which a transducer’s spot size is at a minimum.
2.8 Focal Length (FL)
The interface between the encapsulant and the active side of the die.
2.7 Die Surface View Area (Refer to Annex A, Type I)
The interface between the die and the die attach adhesive and/or the die attach adhesive and the die attach
2.6 Die Attach View Area (Refer to Annex A, Type II)
Figure 4 — Example of Through Transmission Display
of Through Transmission Display.
ultrasound through the complete thickness/depth (Z) of the sample/component. See Figure 4 – Example
the scan plane. A Through Transmission scan furnishes a two-dimensional (area) image of transmitted
microscope. A Through Transmission mode scan contains only amplitude information at each point in
Acoustic data collected in an X-Y plane throughout the depth (Z) using a through transmission acoustic
2.5 Through Transmission Mode
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Joint IPC/JEDEC Standard J-STD-035
Copyright © 1999, JEDEC; 2000, IEC
X-Y-Z
Transducer
X-Y-Z
Transducer 1
Transducer 2
The interface between the encapsulant and the die side of the die attach substrate surrounding the die.
2.14 Top-Side Die Attach Substrate View Area (Refer to Annex A, Type III)
from the sending transducer through the sample to the receiving transducer.
b) In through transmission mode, the time of flight is the time it takes for the acoustic pulse to travel
transducer/receiver to the interface of interest and back.
a) In reflective mode, the time of flight is the time it takes for the acoustic pulse to travel from a single
2.13 Time-of-Flight (TOF)
Figure 6 — Diagram of a Through Transmission Acoustic Microscope System
Computer Controller A-mode Display
Fluid Medium Bath
Receiver
Pulser
Scanning System
Microscope System.
transducer to a receiver on the opposite side. See Figure 6 - Diagram of a Through Transmission Acoustic
An acoustic microscope that transmits ultrasound completely through the sample from a sending
2.12 Through Transmission Acoustic Microscope
Figure 5 — Diagram of a Reflective Acoustic Microscope System
Computer Controller A-mode Display
Fluid Medium Bath
Pulser/Receiver
Scanning System
pulse/echo system.) See Figure 5 - Diagram of a Reflective Acoustic Microscope.
An acoustic microscope that uses one transducer as both the pulser and receiver. (This is also known as a
2.11 Reflective Acoustic Microscope
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.
scan, and maintain planarity.
The holder should position the samples in the proper place, keep the samples from moving during the
3.4 Sample holder
setup
These include packages with delamination and packages without delamination, for use during equipment
3.3 Reference packages or standards
3) Separate receiving transducer or ultrasonic detection system
pulser (can be a pulser/receiver as in 3.1, 1) 2) Ultrasonic
1) Items listed in 3.1 above
3.2 Through transmission acoustic microscope system (see Figure 6) comprised of:
subsurface imaging.
6) A broad band acoustic transducer with a center frequency in the range of 10 to 200 MHz for
the transducer
5) A fluid medium bath, such as deionized water, to provide acoustic coupling between the sample and
probe over the sample and for setting the focus plane within the sample.
4) An electromechanical X-Y-Z (typically computer-controlled) scanning system for moving the acoustic
printing and analysis.
3) A computer-controlled display system for image display (B-mode and C-mode), storage, retrieval,
2) A display of the echo amplitude and phase/polarity versus time (A-mode display).
pulser/receiver 1) Ultrasonic
3.1 Reflective acoustic microscope system (see Figure 5) comprised of:
3 Apparatus
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Joint IPC/JEDEC Standard J-STD-035
Copyright © 1999, JEDEC; 2000, IEC
sample.
designated for imaging. This is done by adjusting the Z-axis distance between the transducer and the
Focus by maximizing the amplitude, in the A-mode display, of the reflection from the interface
4.1.5 Focus
top surface of the sample. The transducer must be perpendicular to the sample surface.
At a fixed distance (Z), align the transducer and/or stage for the maximum reflected amplitude from the
4.1.4 Align the transducer
and from the bottom of the transducer head.
parallel with the scanning plane of the acoustic transducer. Sweep air bubbles away from the unit surface
Place units in the sample holder in the coupling medium such that the upper surface of each unit is
4.1.3 Place units in the sample holder
the reference standard utilized.
the transducer chosen in 4.1.1 to ensure that the critical parameters at the interface of interest correlate to
Verify setup with the reference packages or standards (see 3.3 above) and settings that are appropriate for
4.1.2 Verify setup
determine if defects are present.
reflective mode. Through transmission is effective for the initial inspection of components to
Note — Through transmission mode may require a lower frequency and/or longer focal length than
delineate the interface of interest.
a clear signal from the interface of interest. The transducer should have a high enough frequency to
analyze the interfaces of interest. The transducer selected should have a low enough frequency to provide
, and transducer availability, to configuration the media thickness and acoustic characteristics, package
Select the transducer with the highest useable ultrasonic frequency, subject to the limitations imposed by
4.1.1 Select the transducer
4.1 Equipment Setup
apply to a specific model of acoustic microscope, consult the manufacturer’s operational manual.
This procedure is generic to all acoustic microscopes. For operational details related to this procedure that
4 Procedure
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Copyright © 1999, JEDEC; 2000, IEC
checklist is shown in Annex D.
Record the images and the final instrument setup parameters for documentation purposes. An example
4.2.4 Record
J-STD-020.
Evaluate the acoustic images using the failure criteria specified in other appropriate documents, such as
4.2.3 Evaluate
to the equipment setup to optimize the results and rescan.
limitations of acoustic microscopy listed in, but not limited to, Annex C. If necessary, make adjustments
Consider potential pitfalls in image interpretation listed in, but not limited to, Annex B and some of t
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