Model for Acoustic Microscopy Inspection of Microelectronics Packages With Thin Layers

Manufacturing ◽  
2002 ◽  
Author(s):  
Sridhar Canumalla
Keyword(s):  
Electronic Device ◽  
Electronic Materials ◽  
Ultrasonic Pulse ◽  
Thin Layers ◽  
Acoustic Microscopy ◽  
Microelectronic Devices ◽  
Bond State ◽  
Acoustic Images ◽  
Multilayered Systems ◽  
Geometric Variables

A broadband model is proposed to describe the nature of ultrasonic pulses in multilayered systems with a sub-wavelength thickness layer. This model, which is targeted towards acoustic microscopy of microelectronic devices, can incorporate measured ultrasonic properties of electronic materials and predict the complete ultrasonic pulse-train for all the interfaces in an electronic device. The model is robust, and incorporates material and geometric variables commonly encountered in microelectronics applications. Results are presented to illustrate how delaminations and cracks with foreign material or moisture ingress can appear to be well-bonded and why acoustic images of interfaces with thin layers can sometimes give erroneous indications of the bond state.

A Broadband Model for Ultrasonic Pulses in the Presence of Thin Layers in Microelectronics

2002 ◽  
Author(s):  
Sridhar Canumalla
Keyword(s):  
Electronic Device ◽  
Electronic Materials ◽  
Ultrasonic Pulse ◽  
Thin Layers ◽  
Acoustic Microscopy ◽  
Microelectronic Devices ◽  
Bond State ◽  
Acoustic Images ◽  
Multilayered Systems ◽  
Geometric Variables

Abstract A broadband model is proposed to describe the nature of ultrasonic pulses in multilayered systems with a sub-wavelength thickness layer. This model, which is targeted towards acoustic microscopy of microelectronic devices, can incorporate measured ultrasonic properties of electronic materials and predict the complete ultrasonic pulse-train for all the interfaces in an electronic device. The model is robust, and incorporates material and geometric variables commonly encountered in microelectronics applications. Results are presented to illustrate how delaminations and cracks with foreign material or moisture ingress can appear to be well-bonded and why acoustic images of interfaces with thin layers can sometimes give erroneous indications of the bond state.

scholarly journals Use of Ultrasound Microscopy for Ex Vivo Analysis of Acoustic Impedance in Mouse Liver with Steatohepatitis

Acoustics ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 3-10
Author(s):  
Hideki Kumagai ◽  
Kazuto Kobayashi ◽  
Sachiko Yoshida ◽  
Koji Yokoyama ◽  
Norio Hirota ◽  
...  
Keyword(s):  
Acoustic Impedance ◽  
Ex Vivo ◽  
Acoustic Microscopy ◽  
Control Group ◽  
Scanning Acoustic Microscopy ◽  
Central Frequency ◽  
Deficient Diet ◽  
Acoustic Images ◽  
Ultrasound Microscopy

Scanning acoustic microscopy reveals information on histology and acoustic impedance through tissues. The objective of the present study was to investigate whether acoustic impedance values in the liver over time reflect the progression of steatohepatitis through different grades and stages, and whether this approach can visualize histologic features of the disease. Mice were divided into two groups: a control group and a steatohepatitis group prepared by keeping the mice on a methionine and choline-deficient diet for 56 weeks. The hepatic lobe was excised for measurement of impedance and observation of microscopic structure using a commercially available scanning acoustic microscopy system with a central frequency of 320 MHz. Scanning acoustic microscopy revealed that acoustic impedance through liver tissue with steatohepatitis temporarily decreased with the degree of fat deposition and then increased in parallel with the progression of inflammation and fibrosis. However, the acoustic images obtained did not allow discrimination of detailed microstructures from those seen using light microscopy. In conclusion, estimation of acoustic impedance appears to have potential clinical applications, such as for monitoring or follow-up studies.

A High-Resolution Dry-Contact Acoustic Imaging of the Solder Joints for Ball Grid Array Assembly

2003 ◽  
Author(s):  
Hironori Tohmyoh ◽  
Masumi Saka
Keyword(s):  
Solder Joints ◽  
Ball Grid Array ◽  
Acoustic Imaging ◽  
Acoustic Microscopy ◽  
High Frequency Ultrasound ◽  
Wafer Level ◽  
Matching Layer ◽  
Acoustic Images ◽  
Dry Contact ◽  
Wafer Level Package

A new concept of acoustic microscopy for ball grid array assembly is reported. Commonly, the acoustic microscopy has to be performed with immersing the package in the coupling liquid. On the other hand, the present technique does not require the immersion of the package in the liquid, because the transduction of high frequency ultrasound is performed thorough a thin solid layer. A theoretical model is shown to perform the transduction of ultrasound more effective than usual immersion, and an acoustic matching layer, which realizes the signal amplification and the modulation, is shown. The acoustic imaging of the solder joints of a wafer level package is carried out by the present dry-contact and usual immersion techniques. The dry-contact acoustic images show the defective joint clearly, and the detectability of the defective joint is improved remarkably as compared with the usual immersion images.

Views on an Electronic Materials Education

MRS Bulletin ◽  
1987 ◽  
Vol 12 (4) ◽  
pp. 47-48
Author(s):  
G.Y. Chin
Keyword(s):  
World Economy ◽  
Materials Science ◽  
Electronic Materials ◽  
Dominant Role ◽  
Extreme Case ◽  
Academic Disciplines ◽  
Science And Engineering ◽  
Microelectronic Devices ◽  
Electrical Engineers ◽  
Materials Science And Engineering

Electronic materials constitutes a sub-field of materials. Therefore the issues raised concerning an electronic materials education must necessarily be viewed in the broader context of a comprehensive materials education. Yet electronic materials do differ from other subfields in several ways.First, unlike the traditional metals, ceramics and polymers, which are defined primarily by chemical composition, electronic materials are defined by functions, i.e., they are used in devices that provide electronic functions. As such, electronic materials encompass metals, ceramics, and polymers as well as semiconductors.Second, workers employed in electronic materials industries come from a diverse set of academic disciplines. They are physicists, chemists, chemical engineers, electrical engineers, and mechanical engineers as well as metallurgists, ceramists, and materials science and engineering (MSE) graduates. Thus activities in the electronic materials industries represent an extreme case of interdisciplinary activity which is characteristic of MSE.Third, the electronic materials industries play a dominant role in world economy today and the technology is changing at a dizzying pace. Thus issues in education in electronic materials become more challenging than other subfields and may require fresh and nontraditional approaches.When speaking of electronic materials, one generally thinks of semiconductors, such as silicon and more recently gallium arsenide, that are used in microelectronic devices.

Pulsed-laser deposition growth of copper oxide on α-Al2O3 and MgO

1994 ◽  
Vol 52 ◽  
pp. 528-529
Author(s):  
Michael W. Bench ◽  
C.Barry Carter
Keyword(s):  
Copper Oxide ◽  
Electronic Device ◽  
Electronic Materials ◽  
High Temperature Superconductors ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Ceramic Substrates ◽  
Adhesion Properties ◽  
Wide Range ◽  
Α Al2o3

Copper and its oxides are involved in many electronic materials applications. Cuprous oxide (Cu2O)is a semiconductor finding usage as a thin-film solar-cell material. The copper-oxide-based hightemperature superconductor materials have been extensively investigated. Also, the adhesion andbonding ofcopper to ceramic substrates is of interest for usage in electronic device packaging applications. For the case of alumina substrates, it has been demonstrated that the adhesion properties of thin copper wires is optimized for a ternary bonding environment at the interface. For the growth of oxidematerials, pulsed-laser ablation (PLA) is a viable means of growing films, and allows materials with a wide range of stoichiometrics to be produced. Indeed, this technique has found wide application inthe growth of high-temperature superconductors. In a previous study on PLA growth of CuO and Cu2O, Ogale etal. reported the growth of continuous epitactic Cu2O films on (100) MgO substrates at 700°C, whereas growth onto silicon and zirconia produced polycrystalline films.

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