JEDEC J-STD-035-1999 Acoustic Microscopy for Nonhermetic Encapsulated Electronic Components《非气密封装电子元件用声波显微镜》.pdf

1、JOINTINDUSTRYSTANDARDAcousticMicroscopyforNonhermeticEncapsulatedElectronicComponentsIPC/JEDECJ-STD-035MAY 1999 Reaffirmed September 2010NOTICEEIA/JEDEC standards and publications contain material that has been prepared, reviewed, andapproved through the JEDEC Board of Directors level and subsequent

2、ly reviewed and approvedby the EIA General Counsel.EIA/JEDEC standards and publications are designed to serve the public interest througheliminating misunderstandings between manufacturers and purchasers, facilitatinginterchangeability and improvement of products, and assisting the purchaser in sele

3、cting andobtaining with minimum delay the proper product for use by those other than JEDEC members,whether the standard is to be used either domestically or internationally.EIA/JEDEC standards and publications are adopted without regard to whether or not theiradoption may involve patents or articles

4、, materials, or processes. By such action JEDEC does notassume any liability to any patent owner, nor does it assume any obligation whatever to partiesadopting the EIA/JEDEC standards or publications.The information included in EIA/JEDEC standards and publications represents a sound approachto produ

5、ct specification and application, principally from the solid state device manufacturerviewpoint. Within the JEDEC organization there are procedures whereby an EIA/JEDECstandard or publication may be further processed and ultimately become an ANSI/EIA standard.No claims to be in conformance with this

6、 standard may be made unless all requirements stated inthe standard are met.Inquiries, comments, and suggestions relative to the content of this EIA/JEDEC standard orpublication should be addressed to JEDEC Solid State Technology Association, 2500 WilsonBoulevard, Arlington, VA 22201-3834, (703)907-

7、7560/7559 or www.jedec.orgPublished by ELECTRONIC INDUSTRIES ALLIANCE 1999Engineering Department2500 Wilson BoulevardArlington, VA 22201-3834This document may be downloaded free of charge, however EIA retains thecopyright on this material. By downloading this file the individual agrees not tocharge

8、or resell the resulting material.PRICE: IPC/JEDEC Members: $18.00, Non-Members: $35.00Printed in the U.S.A.All rights reservedPLEASE!DON”T VIOLATETHELAW!This document is copyrighted by the Electronic Industries Alliance and may not bereproduced without permission.Organizations may obtain permission

9、to reproduce a limited number of copiesthrough entering into a license agreement. For information, contact:JEDEC Solid State Technology Association2500 Wilson BoulevardArlington, Virginia 22201-3834or call (703) 907-7559Joint IPC/JEDEC Standard J-STD-035Page 1ACOUSTIC MICROSCOPY FOR NONHERMETICENCAP

10、SULATED ELECTRONIC COMPONENTS(From JEDEC Board Ballot JCB-98-99, under the cognizance of the JC-14.1 Committee on ReliabilityTest Methods for Packaged Devices an with the IPC.)1 ScopeThis test method defines the procedures for performing acoustic microscopy on nonhermetic encapsulatedelectronic comp

11、onents. This method provides users with an acoustic microscopy process flow fordetecting anomalies (delamination, cracks, mold compound voids, etc.) nondestructively in plasticpackages while achieving reproducibility.2 Definitions2.1 A-modeAcoustic data collected at the smallest X-Y-Z region defined

12、 by the limitations of the given acousticmicroscope. An A-mode display contains amplitude and phase/polarity information as a function of timeof flight at a single point in the X-Y plane. See Figure 1 - Example of A-mode Display.Figure 1 Example of A-mode Display2.2 B-modeAcoustic data collected alo

13、ng an X-Z or Y-Z plane versus depth using a reflective acoustic microscope. AB-mode scan contains amplitude and phase/polarity information as a function of time of flight at eachpoint along the scan line. A B-mode scan furnishes a two-dimensional (cross-sectional) description alonga scan line (X or

14、Y). See Figure 2 - Example of B-mode Display.Joint IPC/JEDEC Standard J-STD-035Page 22.2 B-mode (contd)Figure 2 Example of B-mode Display (bottom half of picture on left)2.3 Back-Side Substrate View Area (Refer to Annex A, Type IV)The interface between the encapsulant and the back of the substrate w

15、ithin the outer edges of the substratesurface.2.4 C-modeAcoustic data collected in an X-Y plane at depth (Z) using a reflective acoustic microscope. A C-modescan contains amplitude and phase/polarity information at each point in the scan plane. A C-mode scanfurnishes a two-dimensional (area) image o

16、f echoes arising from reflections at a particular depth (Z). SeeFigure 3.Figure 3 Example of C-mode DisplayJoint IPC/JEDEC Standard J-STD-035Page 32.5 Through Transmission ModeAcoustic data collected in an X-Y plane throughout the depth (Z) using a through transmission acousticmicroscope. A Through

17、Transmission mode scan contains only amplitude information at each point inthe scan plane. A Through Transmission scan furnishes a two-dimensional (area) image of transmittedultrasound through the complete thickness/depth (Z) of the sample/component. See Figure 4 Exampleof Through Transmission Displ

18、ay.Figure 4 Example of Through Transmission Display2.6 Die Attach View Area (Refer to Annex A, Type II)The interface between the die and the die attach adhesive and/or the die attach adhesive and the die attachsubstrate.2.7 Die Surface View Area (Refer to Annex A, Type I)The interface between the en

19、capsulant and the active side of the die.2.8 Focal Length (FL)The distance in water at which a transducers spot size is at a minimum.2.9 Focus PlaneThe X-Y plane at a depth (Z), which the amplitude of the acoustic signal is maximized.2.10 Leadframe (L/F) View Area (Refer to Annex A, Type V)The image

20、d area which extends from the outer L/F edges of the package to the L/F “tips” (wedgebond/stitch bond region of the innermost portion of the L/F.)Joint IPC/JEDEC Standard J-STD-035Page 42.11 Reflective Acoustic MicroscopeAn acoustic microscope that uses one transducer as both the pulser and receiver

21、. (This is also known as apulse/echo system.) See Figure 5 - Diagram of a Reflective Acoustic Microscope.Figure 5 Diagram of a Reflective Acoustic Microscope System2.12 Through Transmission Acoustic MicroscopeAn acoustic microscope that transmits ultrasound completely through the sample from a sendi

22、ngtransducer to a receiver on the opposite side. See Figure 6 - Diagram of a Through Transmission AcousticMicroscope System.Figure 6 Diagram of a Through Transmission Acoustic Microscope System2.13 Time-of-Flight (TOF)a) In reflective mode, the time of flight is the time it takes for the acoustic pu

23、lse to travel from a singletransducer/receiver to the interface of interest and back.b) In through transmission mode, the time of flight is the time it takes for the acoustic pulse to travelfrom the sending transducer through the sample to the receiving transducer.2.14 Top-Side Die Attach Substrate

24、View Area (Refer to Annex A, Type III)The interface between the encapsulant and the die side of the die attach substrate surrounding the die.X-Y-ZScanning SystemPulser/ReceiverFluid Medium BathTransducerA-mode Display Computer ControllerX-Y-ZScanning System PulserReceiverFluid Medium BathTransducer

25、1A-mode Display Computer ControllerTransducer 2Joint IPC/JEDEC Standard J-STD-035Page 53 Apparatus3.1 Reflective acoustic microscope system (see Figure 5) comprised of:1) Ultrasonic pulser/receiver2) A display of the echo amplitude and phase/polarity versus time (A-mode display).3) A computer-contro

26、lled display system for image display (B-mode and C-mode), storage, retrieval,printing and analysis.4) An electromechanical X-Y-Z (typically computer-controlled) scanning system for moving the acousticprobe over the sample and for setting the focus plane within the sample.5) A fluid medium bath, suc

27、h as deionized water, to provide acoustic coupling between the sample andthe transducer6) A broad band acoustic transducer with a center frequency in the range of 10 to 200 MHz forsubsurface imaging.3.2 Through transmission acoustic microscope system (see Figure 6) comprised of:1) Items listed in 3.

28、1 above2) Ultrasonic pulser (can be a pulser/receiver as in 3.1, 1)3) Separate receiving transducer or ultrasonic detection system3.3 Reference packages or standardsThese include packages with delamination and packages without delamination, for use during equipmentsetup.3.4 Sample holderThe holder s

29、hould position the samples in the proper place, keep the samples from moving during thescan, and maintain planarity.Joint IPC/JEDEC Standard J-STD-035Page 64 ProcedureThis procedure is generic to all acoustic microscopes. For operational details related to this procedure thatapply to a specific mode

30、l of acoustic microscope, consult the manufacturers operational manual.4.1 Equipment Setup4.1.1 Select the transducerSelect the transducer with the highest useable ultrasonic frequency, subject to the limitations imposed bythe media thickness and acoustic characteristics, package configuration , and

31、 transducer availability, toanalyze the interfaces of interest. The transducer selected should have a low enough frequency to providea clear signal from the interface of interest. The transducer should have a high enough frequency todelineate the interface of interest.Note Through transmission mode

32、may require a lower frequency and/or longer focal length thanreflective mode. Through transmission is effective for the initial inspection of components todetermine if defects are present.4.1.2 Verify setupVerify setup with the reference packages or standards (see 3.3 above) and settings that are ap

33、propriate forthe transducer chosen in 4.1.1 to ensure that the critical parameters at the interface of interest correlate tothe reference standard utilized.4.1.3 Place units in the sample holderPlace units in the sample holder in the coupling medium such that the upper surface of each unit isparalle

34、l with the scanning plane of the acoustic transducer. Sweep air bubbles away from the unit surfaceand from the bottom of the transducer head.4.1.4 Align the transducerAt a fixed distance (Z), align the transducer and/or stage for the maximum reflected amplitude from thetop surface of the sample. The

35、 transducer must be perpendicular to the sample surface.4.1.5 FocusFocus by maximizing the amplitude, in the A-mode display, of the reflection from the interfacedesignated for imaging. This is done by adjusting the Z-axis distance between the transducer and thesample.Joint IPC/JEDEC Standard J-STD-0

36、35Page 74.2 Perform Acoustic Scans4.2.1 Inspect for any anomaliesInspect the acoustic image(s) for any anomalies, verify that the anomaly is a package defect or an artifactof the imaging process, and record the results. (See Annex A for an example of a check sheet that may beused.)To determine if an

37、 anomaly is a package defect or an artifact of the imaging process it is recommended toanalyze the A-mode display at the location of the anomaly. Physical analysis of the package may also berequired to confirm the nature of the anomaly.4.2.2 Consider potential pitfallsConsider potential pitfalls in

38、image interpretation listed in, but not limited to, Annex B and some of thelimitations of acoustic microscopy listed in, but not limited to, Annex C. If necessary, make adjustmentsto the equipment setup to optimize the results and rescan.4.2.3 EvaluateEvaluate the acoustic images using the failure c

39、riteria specified in other appropriate documents, such asJ-STD-020.4.2.4 RecordRecord the images and the final instrument setup parameters for documentation purposes. An examplechecklist is shown in Annex D.Joint IPC/JEDEC Standard J-STD-035Page 8Annex A Acoustic Microscopy Check SheetType IV Delami

40、nation:Substrate/Encapsulant(Backside)Type I Delamination:Encapsulant/Die SurfaceType III Delamination:Encapsulant/Substrate(Die Side)Type II Delamination:Die Attach RegionType V Delamination:Encapsulant/Lead InterconnectCircuit Side Scan Noncircuit Side ScanType VI Delamination:Intra-Laminate(Lamin

41、ate Substrates Only)Type VII Delamination:Heat Sink/SubstrateJoint IPC/JEDEC Standard J-STD-035Page 9Annex A Acoustic Microscopy Check Sheet ( contd)CIRCUIT SIDE SCANImage File Name/pathDelamination(Type I) Die Circuit Surface/ Encapsulant number affected : Average. %Location: Corner Edge Center(Typ

42、e II) Die/Die Attach number affected : Average. %Location: Corner Edge Center(Type III) Encapsulant/Substrate number affected : Average. %Location: Corner Edge Center(Type V)Interconnect tip number affected: Average %Interconnect number affected: Max. % length(Type VI) Intra-Laminate number affected

43、 : Average. %Location: Corner Edge CenterComments:CracksAre cracks present: Yes No If yes:Do any cracks intersect: bond wire ball bond wedge bond tab bump tab leadDo es crack extend from lead finger to any other internal feature: Yes NoDoes crack extend more than two-thirds the distance from any int

44、ernal feature to the external surfaceof the package: Yes NoAdditional verification required: Yes NoComments:Mold Compound VoidsAre voids present: Yes No If yes:Approx. size Location (if multiple voids, use comment section)Do any voids intersect: bond wire ball bond wedge bond tab bump tab leadAdditi

45、onal verification required: Yes NoComments:Joint IPC/JEDEC Standard J-STD-035Page 10Annex A Acoustic Microscopy Check Sheet ( contd)NONCIRCUIT SIDE SCANImage File Name/pathDelamination(Type IV) Encapsulant/Substrate number affected: Average. %Location: Corner Edge Center(Type II) Substrate/Die Attac

46、h number affected: Average. %Location: Corner Edge Center(Type V) Interconnect number affected: Max. % length(Type VI) Intra-Laminate number affected : Average. %Location: Corner Edge Center(Type VII) Heat Spreader number affected : Average. %Location: Corner Edge CenterAdditional verification requi

47、red: Yes NoComments:CracksAre cracks present: Yes No If yes:Does crack extend more than two-thirds the distance from any internal feature to the external surfaceof the package: Yes NoAdditional verification required: Yes NoComments:Mold Compound VoidsAre voids present: Yes No If yes:Approx. size Loc

48、ation (if multiple voids, use comment section)Additional verification required: Yes NoComments:Joint IPC/JEDEC Standard J-STD-035Page 11Annex B Potential Image PitfallsOBSERVATIONS CAUSES/COMMENTSUnexplained loss of Gain setting too lowfront surface signal Symbolization on package surfaceEjector pin knockoutsPin 1 and other mold marksDust, air bu bbles, fingerprints, residueScratches, scribe marks, pencil marksCambered package edgeUnexplained loss of Gain setting too lowsubsurface signal Transducer frequency too highAcoustically absorbe