Ultrasonic Bonding Technology for Micro System Integration

Yasuda, Kimihiko

doi:10.5104/jiep.22.395

Cited by 2 publications

(2 citation statements)

References 18 publications

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“…In ultrasonic bonding [ 9 ], fast horizontal vibration is generated using ultrasound to bond two metal surfaces through rapid friction at the bonding interface. The friction damages the surface oxidation layers, removes impurities, and generates a high thermal energy, thereby drastically reducing the bonding time.…”

Section: Introductionmentioning

confidence: 99%

Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments

Lee

Hung

et al. 2021

Micromachines

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This study employed finite element analysis to simulate ultrasonic metal bump direct bonding. The stress distribution on bonding interfaces in metal bump arrays made of Al, Cu, and Ni/Pd/Au was simulated by adjusting geometrical parameters of the bumps, including the shape, size, and height; the bonding was performed with ultrasonic vibration with a frequency of 35 kHz under a force of 200 N, temperature of 200 °C, and duration of 5 s. The simulation results revealed that the maximum stress of square bumps was greater than that of round bumps. The maximum stress of little square bumps was at least 15% greater than those of little round bumps and big round bumps. An experimental demonstration was performed in which bumps were created on Si chips through Al sputtering and lithography processes. Subtractive lithography etching was the only effective process for the bonding of bumps, and Ar plasma treatment magnified the joint strength. The actual joint shear strength was positively proportional to the simulated maximum stress. Specifically, the shear strength reached 44.6 MPa in the case of ultrasonic bonding for the little Al square bumps.

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Section: Introductionmentioning

confidence: 99%

Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments

Lee

Hung

et al. 2021

Micromachines

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“…28) However, in a real body, acoustic rays are not completely straight due to inhomogeneous sound velocity and scattering, and this reduces any correction effect. In our previous study, 29) the correction effect in homogeneous tissue was evaluated using numerical simulation. In this study, we investigate the effect of inhomogeneous sound velocity and scattering.…”

Section: Introductionmentioning

confidence: 99%

Phase aberration correction for focused ultrasound transmission by refraction compensation

Yasuda¹,

Yoshikawa²,

Tanaka³

2019

Jpn. J. Appl. Phys.

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Phase aberration of focused ultrasound by tissue structure causes focus degradation and reduces the quality of B-mode images. Refraction at the boundary between subcutaneous fat and muscle is one of the dominant factors behind such degradation. To correct this, we propose a refraction compensation method in which ultrasound is transmitted and received twice. The boundary shape between different tissues is detected by the first ultrasound transmission. Next, ultrasound rays from probe elements to the target are calculated taking refraction into account. Corrected delay times are calculated from the length of the rays and the sound velocity of the medium. Finally, ultrasound is transmitted a second time using the corrected delay time and a B-mode image is created. We evaluate the correction effect of the proposed method by numerical simulation and experiments with non-compensated and refraction-compensated cases of intensity distribution of the focused ultrasound. Results show that focus degradation is effectively corrected by the proposed method.

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Ultrasonic Bonding Technology for Micro System Integration

Cited by 2 publications

References 18 publications

Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments

Geometrical Effects on Ultrasonic Al Bump Direct Bonding for Microsystem Integration: Simulation and Experiments

Phase aberration correction for focused ultrasound transmission by refraction compensation

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