The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform

Aashish Shah - One of the best experts on this subject based on the ideXlab platform.

  • advanced Wire Bonding technology for ag Wire
    Electronics Packaging Technology Conference, 2015
    Co-Authors: Aashish Shah, Thomas Rockey, Wu Jie, Oranna Yauw, Ob Chylak
    Abstract:

    With the introduction and proliferation of Cu Wire Bonding, the cost of Wire Bonding packages is greatly reduced compared to traditional Au Wire Bonding. Wire Bonding is still the most popular interconnect technology and the work horse of the industry. Technology development and innovation in Wire Bonding has provided new packaging solutions that improve performance and reduce the cost. This paper reviews the pros and cons of each Bonding Wire type that is being used for ball Bonding including Au, Cu, and Ag Wire. Although Cu Wire is by far the cheapest Bonding Wire, in certain cases Cu Wire is not a viable solution due to either the lack of advanced Cu Wire equipment and process or the special requirements of the package. For example, Cu Wire Bonding has challenges with memory devices that require low loops and thin overhang die. In this case for memory devices, Ag Wire is a good alternative that can provide significant cost reduction. This paper further examines the challenges and solutions for Ag Wire Bonding process including Free Air Ball (FAB) formation, the 1st bond and the 2nd bond. The key developments in ball Bonding equipment, process and material to overcome these challenges are discussed. We studied the FAB formation process and studied the effect of cover gas system design, EFO (Electronic Flame Off) current, EFO gap, and other factors that affect the ball formation process. We demonstrate fine pitch capability of Ag Wire Bonding including 1st bond and 2nd bond using 0.6 mil Ag Wire. Both forward Bonding processes as well as SSB (Standoff Stitch Bond) are studied using new response based processes. The different Wire alloys from 87% Ag to 97% Ag are also studied and compared in order to understand the differences in Wire performance.

  • advances in Wire Bonding technology for different Bonding Wire material
    International Symposium on Microelectronics, 2015
    Co-Authors: Aashish Shah, Ob Chylak, Nelso Wong
    Abstract:

    With all the advances in 2.5D and 3D packaging, Wire Bonding is still the most popular interconnect technology and the workhorse of the industry. Wire Bonding technology has been the lower cost solution comparing to flip chip. Wire Bonding package cost is much reduced with the introduction of Copper Wire Bonding. Technology development and innovation in Wire Bonding provides new packaging solutions that improves performance and reduces cost. This paper reviews the recent innovations in ball Bonding technology to provide optimized ball Bonding solutions targeted for different Bonding Wire material. It examines the different challenges for the alternative Wire types including Cu Wire, Pd coated, and AuPd coated Cu Wire and Ag Alloy Wire. We will discuss key development in ball Bonding equipment, process and material to overcome the challenges and provide robust low cost solutions. The advantages of each Wire type are outlined, and guidelines to select the right Bonding Wire type per application requirements...

  • advances in Wire Bonding technology for different Bonding Wire material
    International Symposium on Microelectronics, 2015
    Co-Authors: Aashish Shah, Bob Chylak, Hui Xu, Nelson Wong
    Abstract:

    With all the advances in 2.5D and 3D packaging, Wire Bonding is still the most popular interconnect technology and the workhorse of the industry. Wire Bonding technology has been the lower cost sol...

  • ultrasonic friction power during al Wire wedge wedge Bonding
    Journal of Applied Physics, 2009
    Co-Authors: Aashish Shah, Holge Gaul, M Schneiderramelow, H Reichl, Michael Maye, Y Zhou
    Abstract:

    Al Wire Bonding, also called ultrasonic wedge-wedge Bonding, is a microwelding process used extensively in the microelectronics industry for interconnections to integrated circuits. The Bonding Wire used is a 25μm diameter AlSi1 Wire. A friction power model is used to derive the ultrasonic friction power during Al Wire Bonding. Auxiliary measurements include the current delivered to the ultrasonic transducer, the vibration amplitude of the Bonding tool tip in free air, and the ultrasonic force acting on the Bonding pad during the bond process. The ultrasonic force measurement is like a signature of the bond as it allows for a detailed insight into mechanisms during various phases of the process. It is measured using piezoresistive force microsensors integrated close to the Al Bonding pad (Al–Al process) on a custom made test chip. A clear break-off in the force signal is observed, which is followed by a relatively constant force for a short duration. A large second harmonic content is observed, describing...

  • online methods to measure breaking force of Bonding Wire using a cmos stress sensor and a proximity sensor
    Sensors and Actuators A-physical, 2008
    Co-Authors: Aashish Shah, Michael Mayer, Norman Y Zhou
    Abstract:

    Two real-time, in situ methods to measure the breaking force of fine Bonding Wires while on the Wire bonder are reported and compared. The first method uses a special test chip with a piezoresistive microsensor integrated next to the Bonding pad. A 25m diameter Au Wire piece is attached with a ball bond to the test pad of the microsensor. The Wire piece between the ball bond and the lower edge of the Wire clamps is 15 mm in length. The clamps tear the Wire at a speed of 2 mm/s. The Wire breaks at the heat-affected zone (HAZ) next to the ball bond. The microsensor is calibrated using FE models. The numerical results show that the microsensor signal is highly sensitive to ball and pad geometry, values of the piezoresistive coefficients, and the z-location of the microsensor under the Bonding pad. This results in a high estimated error of about 46% for the calibration factor of the microsensor. The second method uses a proximity sensor attached to the Wire clamp of the Bonding machine for which an accurate calibration is available. The proximity sensor is calibrated by hanging a weight of 22.2 g to the Wire clamp. The average breaking force at the HAZ is measured to be 98.6 ± 1.67 mN. This value is approximately 77% of the breaking load of the non-heat affected Wire as measured with a standard tensile tester. Using the proximity sensor method, an accurate calibration of the microsensor is found. The signal precisions of the microsensor and the proximity sensor are found to be approximately 1%. These methods are ideally suited for the automatic measurement of tail breaking force (TBF) as observed in thermosonic Wire Bonding processes.

Hideo Kasami - One of the best experts on this subject based on the ideXlab platform.

  • Bonding Wire loop antenna in standard ball grid array package for 60 ghz short range Wireless communication
    IEEE Transactions on Antennas and Propagation, 2013
    Co-Authors: Yukako Tsutsumi, Shuichi Obayashi, Hiroki Shoki, Takayoshi Ito, Koh Hashimoto, Hideo Kasami
    Abstract:

    High-speed short-range Wireless communication systems are expected to utilize the 60-GHz band. This paper presents a Bonding Wire loop antenna in a standard ball grid array (BGA) package for 60-GHz short-range Wireless communication. The proposed antenna has a loop shape and consists of two Bonding Wires connecting to a complementary metal–oxide–semiconductor (CMOS) chip and a metal plate on an interposer in a BGA package. The antenna can be fabricated at low cost by a conventional BGA package fabrication process. The BGA package is mounted on a printed circuit board (PCB) that consists of resin substrate, such as FR-4. The broadband impedance characteristic is achieved by adjusting the position of the metal pad for Wire Bonding. The antenna gain is improved by forming cranked ledges and notches in the metal patterns of the PCB, and the wide-angle radiation characteristic is realized. The sizes of the fabricated antenna and BGA package are approximately 0.6 mm $\,\times \,$ 1.0 mm $\,\times \,$ 0.3 mm and 9.0 mm $\,\times \,$ 9.0 mm $\,\times \,$ 0.9 mm, respectively. Performing measurements, the antenna gain with the PCB is from $-$ 2.4 to 4.9 dBi over the 57- to 65-GHz frequency range and over an angular range of 60 $^\circ$ in the horizontal plane.

Yukako Tsutsumi - One of the best experts on this subject based on the ideXlab platform.

  • Bonding Wire loop antenna in standard ball grid array package for 60 ghz short range Wireless communication
    IEEE Transactions on Antennas and Propagation, 2013
    Co-Authors: Yukako Tsutsumi, Shuichi Obayashi, Hiroki Shoki, Takayoshi Ito, Koh Hashimoto, Hideo Kasami
    Abstract:

    High-speed short-range Wireless communication systems are expected to utilize the 60-GHz band. This paper presents a Bonding Wire loop antenna in a standard ball grid array (BGA) package for 60-GHz short-range Wireless communication. The proposed antenna has a loop shape and consists of two Bonding Wires connecting to a complementary metal–oxide–semiconductor (CMOS) chip and a metal plate on an interposer in a BGA package. The antenna can be fabricated at low cost by a conventional BGA package fabrication process. The BGA package is mounted on a printed circuit board (PCB) that consists of resin substrate, such as FR-4. The broadband impedance characteristic is achieved by adjusting the position of the metal pad for Wire Bonding. The antenna gain is improved by forming cranked ledges and notches in the metal patterns of the PCB, and the wide-angle radiation characteristic is realized. The sizes of the fabricated antenna and BGA package are approximately 0.6 mm $\,\times \,$ 1.0 mm $\,\times \,$ 0.3 mm and 9.0 mm $\,\times \,$ 9.0 mm $\,\times \,$ 0.9 mm, respectively. Performing measurements, the antenna gain with the PCB is from $-$ 2.4 to 4.9 dBi over the 57- to 65-GHz frequency range and over an angular range of 60 $^\circ$ in the horizontal plane.

  • Bonding Wire loop antenna built into standard bga package for 60 ghz short range Wireless communication
    International Microwave Symposium, 2011
    Co-Authors: Yukako Tsutsumi, Shuichi Obayashi, Hiroki Shoki, Tasuku Morooka
    Abstract:

    The unlicensed 60 GHz frequency band is suitable for high-speed Wireless systems with transmission rates of 1 Gbps or more. In this paper, we propose a Bonding Wire antenna built into a BGA package for 60 GHz short-range Wireless communication. This antenna utilizes two Bonding Wires and a metal plate on an interposer in a BGA package and has a loop shape. The proposed antenna is built into a standard BGA package without special modification, so that it can be fabricated at low cost by conventional BGA package fabrication process. The first and unique evaluation of the antenna fully sealed by encapsulation resin was done by measurement. We describe the operation mechanism of the proposed antenna, the design procedure and the measurement results.

Mingxiang Chen - One of the best experts on this subject based on the ideXlab platform.

  • fluid solid coupling thermo mechanical analysis of high power led package during thermal shock testing
    Microelectronics Reliability, 2012
    Co-Authors: Qin Zhang, Kai Wang, Mingxiang Chen
    Abstract:

    Abstract The virtual design by numerical simulation to model various accelerated reliability testing conditions is adopted to validate and improve the reliability of the high power LED package. In this study, the reliability of the high power LED package during thermal shock testing is investigated by fluid–solid coupling thermo-mechanical modeling by considering nonlinear time and temperature dependent material properties. Through fluid–solid coupling transient thermal transfer analysis, it is found that the maximum thermal gradient exceeds 75 K during the rapid cooling process and 91 K during the rapid heating process of the thermal shock testing which is ignored in the traditional isothermal assumption. The calculation results indicate that the equivalent plastic strain range of the Bonding Wire within the LED package with consideration of the temperature gradient is much higher than that with the isothermal assumption. The assumption of the isothermal condition is not appropriate which will lead to overestimation of the predicted lifetime. The viscoelastic behaviors of the silicone have significant influences on the lifetime prediction of the Bonding Wire and silicone with low elastic modulus and coefficient of thermal expansion (CTE) can significantly enhance the reliability of the Bonding Wire under the thermal shock loading. The results in this study could provide a guideline on design for reliability in the high power LED packaging.

  • study on the reliability of application specific led package by thermal shock testing failure analysis and fluid solid coupling thermo mechanical simulation
    IEEE Transactions on Components Packaging and Manufacturing Technology, 2012
    Co-Authors: Qin Zhang, Run Chen, Feng Jiao, Kai Wang, Mingxiang Chen
    Abstract:

    Reliability is essential for large-scale applications of high-power light-emitting diode (LED) devices, modules, and systems for general illumination. In this paper, the reliability of a novel application-specific LED package (ASLP) is investigated by thermal shock testing, failure analysis, and fluid-solid coupling thermo-mechanical simulation. The reliability of the ASLP modules was validated with a dual-bath liquid thermal shock testing from 233 to 398 K. The non-destructive failure analysis was conducted to the catastrophic failure ASLP samples by fluorescent penetrant inspection. The delaminations at the interfaces within the ASLP module were detected. The failure mechanisms were identified by digital optical microscopy and field emission scanning electron microscope inspection after the decapsulation. The experimental results show that fracture failure occurs at the wedge joint of the Bonding Wire, which leads to the catastrophic failure of the ASLP module. The stress and strain behaviors of the ASLP module, especially the Bonding Wire under thermal shock loading, were analyzed through thermo-mechanical modeling with the nonlinear time- and temperature-dependent material properties. Significant thermal gradient within the ASLP module during the thermal shock testing was taken into consideration by the fluid-solid coupling transient thermal transfer analysis. The effects of the delaminations detected by the fluorescent penetrant inspection on the reliability of the Bonding Wire were also examined. It is found the delaminations existing at the interfaces within the ASLP module induce significant plastic strain to the wedge joint and results in fracture failure. The results from the numerical simulation can make a good prediction of the failure mechanism of the ASLP modules under thermal shock loading.

Kuoning Chiang - One of the best experts on this subject based on the ideXlab platform.

  • analysis of led Wire Bonding process using arbitrary lagrangian eulerian and equilibrium mesh smoothing algorithm
    International Conference on Electronic Packaging and iMAPS All Asia Conference, 2015
    Co-Authors: Chechia Yang, Chiachi Tsai, Yenfu Su, Kuoning Chiang
    Abstract:

    In light emitting diode (LED) packaging, Wire Bonding is used to connect the power of chip. The contact force during thermosonic Bonding process might be able to make the failures, such as pad peeling, cracking, and delamination. This study presents an effective simulation technology with Bonding Wire geometry validation for the LED Wire Bonding process. An axisymmetric finite element (FE) model using explicit method with a second level accuracy arbitrary Lagrangian-Eulerian (ALE) algorithm is constructed in this research. In addition, ALE using the equilibrium smoothing algorithm can make the contact behavior and geometric shape of Bonding Wire be the same as experimental results, and element distortion would be reduced.

  • life prediction of high cycle fatigue in aluminum Bonding Wires under power cycling test
    IEEE Transactions on Device and Materials Reliability, 2014
    Co-Authors: Tuanyu Hung, Liling Liao, Chinchun Wang, Kuoning Chiang
    Abstract:

    In this paper, a 3-D finite-element (FE) model was established based on real test samples. Coupled electrothermal and thermal-mechanical FE analyses were conducted to analyze the mechanical behavior of Bonding Wire under cyclic power loading. The current crowding phenomenon may be improved by increasing the Wire number. The junction temperature can be decreased by decreasing the joule heat from the current crowding around the Bonding Wire. The findings suggest that the power module with Wire configuration design shall be operated in a higher power load; meanwhile, the identical reliability can be guaranteed. The temperature predicted by the simulation was consistent with the experimental data. Incremental equivalent plastic strain was not observed when the current loading was low. However, the plastic ratio progressively enhanced with the current load. With a high current load, the yielding effect should be considered. Plastic strain dominated the failure mechanism. The concepts of high- and low-cycle fatigue should be incorporated into the life prediction model for modules subjected to low and high current loadings, respectively. After the simulation results were validated with the experimental data, two models for the design of power modules were proposed.

  • thermal mechanical behavior of the Bonding Wire for a power module subjected to the power cycling test
    Microelectronics Reliability, 2011
    Co-Authors: Tuanyu Hung, Shihying Chiang, Chinhsiu Huang, Kuoning Chiang
    Abstract:

    Abstract Two analytical methods were proposed in this research, coupled electro-thermal finite element (FE) analysis and thermal–mechanical FE analysis, to analyze the mechanical behavior of Bonding Wire of power module under cyclic power loads, and the International Electrotechnical Commission standard is adopted in conducting a power cycling test. The exterior temperature distribution was measured by an infrared thermometer. Moreover, the junction temperature is calculated from the given thermal impedance of the semiconductor chip, chip power loss, and case temperature. Subsequently, the simulated temperature distribution via electro-thermal FE analysis is compared with experimental results to validate the methodology used in the aforementioned analysis. The analysis shows compressive stress at the Wire/chip interface due to CTE mismatch between the aluminum and the chip. Moreover, the major driving force contributing to the shear stress at the interface is the self-expansion of the Wire bump.