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Bonding dynamics during ultrasonic bonding of Cu free air ball (FAB) is investigated by measuring dynamic strain with piezoresistive strain sensor. Change in dynamic strain with elevating substrate temperature up to 200°C was investigated. It was clearly observed that elevating substrate temperature significantly enhanced deformation of the Cu FAB while the application of pressing load and ultrasonic...
Dynamic changes in distribution of mechanical strain generated during wire bonding in Si under and near the bonding pad were measured by using a piezoresistive linear array sensor. The sensor was designed to be able to determine strains in the directions normal and parallel to the surface. Bonding dynamics of Cu and Au balls were investigated. We can clearly observe the oscillating strain according...
We have developed a strain gauge sensor to measure two axial dynamic strain and temperature evolution during ultrasonic flip-chip bonding. The sensor detects strain from change in resistance due to the piezoresistance effect of Si and temperature from change in current-voltage characteristics of pn-junction. The spatial resolution of the sensor is 20 µm. Au planar microbumps were used for the measurement...
Dynamic change in distribution of strain generated in Si under a pad electrode was measured during ultrasonic ball bonding by using newly developed Si strain sensor. The sensor was designed to be able to determine strains in the directions normal and parallel to the surface. Bonding of Cu and Au was measured. It was clearly observed that the position of the largest compressive strain moved from the...
Room temperature microjoining of Au-Au or Cu-Cu bumps in the air ambient has been achieved by using the cone-shaped bumps with ultrasonic assist. This paper reports bonding mechanism investigated from the results of ex-situ and in-situ measurements. As an ex-situ measurement, we firstly investigate effect of the application of ultrasonic vibration on magnitude of plastic deformation of the compliant...
We discuss bonding mechanism of ultrasonic bonding of cone-shaped bump. Room-temperature microjoining of Au-Au or Cu-Cu bumps in the air ambient has been achieved by using the cone-shaped bumps with ultrasonic assist. We have investigated two characteristics of ultrasonic bonding. We first investigate effect of the application of ultrasonic vibration on magnitude of plastic deformation of the compliant...
Room-temperature bonding technique using cone-shaped microbumps with the aid of ultrasonic vibration is applied to the fabrication of a near-infrared image sensor. The image sensor is fabricated using the flip-chip bonding of an InGaAs/InP photodiode-array chip and a Si CMOS readout IC chip. The pixel pitch is 15 μm to compose VGA class (640 × 512 pixels) resolution. High-quality imaging of a heated...
Room temperature microjoining of Au or Cu bumps in the air ambient has been achieved by bonding cone-shaped microbumps with ultrasonic application. This technology has been applied to fabrication of near infrared (NIR) image sensor of q-VGA (quarter video graphic array) resolution, where InGaAs/InP phtosensor array is joined with CMOS read out in the pixel level and, therefore, low temperature bonding...
We show that room temperature bonding of a 332 × 268 bump array can be realized by using ultrasonic bonding of cone-shaped bump. 25 μm-pitch area array of cone-shaped Au bump was fabricated on a Si wafer by using a photolithography and electroplating. A conventional planar electrode made of electroplated Au was used as the counter electrode. Ultrasonic bonding was carried out at room temperature in...
We show that room temperature microjoining a 332 × 268 array of bumps can be realized by using ultrasonic bonding of cone-shaped microbump. 20 µm-pitch area array of cone-shaped Au bump was fabricated on a Si wafer by using a photolithography and electroplating. A flat planar electrode made of electoplated Au was used as the counter electrode. Ultrasonic bonding was carried out at room temperature...
Ultrasonic bonding was applied to cone-shaped microbump made of Au on a Si chip to perform bonding at room temperature. Array of cone-shaped microbump having 10 μm in diameter and 20μm in pitch was formed on Si using photolithography and electroplating. The counter electrode was a planar electrode which was also made by using electroplating of Au. Bonding was carried out at room temperature under...
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