Ultrasonic Bonding of Cone Bump for Integration of Large-Scale Integrated Circuits in Flexible Electronics

Additive-type printing techniques such as gravure-offset printing and screen printing are effective for low-cost and ecofriendly electrode pattern formation. Gravure-offset printing is effective for fine pattern formation with widths on the order of 10–20 µm, whereas screen printing is effective for the formation of large-area patterns. However, it is difficult to simultaneously form fine and large-area patterns using these printing techniques. In this study, we demonstrate that fine (minimum width of 15 µm) and medium- as well as large-area patterns can be formed simultaneously using our developed screen-offset printing technique, which is a combination of screen printing on a silicone blanket and transfer printing from the blanket to a substrate. Furthermore, we demonstrate the application of our method to printing on adhesive materials, which allows electrode formation without applying heat to the film substrate.

Section: Maskmentioning

confidence: 99%

Simultaneous formation of fine and large-area electrode patterns using screen-offset printing and its application to the patterning on adhesive materials

Nomura¹,

Ushijima²,

Nagase³

et al. 2016

“…[4][5][6] In our previous work, room-temperature bonding of an InGaAs/InP chip to a Si CMOS chip has been realized by using a cone-shaped Au microbump with ultrasonic application. 7,8) The bonding technology has been extended to boding Si chips to interconnects on poly(ethylene naphthalate) (PEN) film, 9) which can be applied to flexible electronics. The bonding on PEN film also requires lowtemperature bonding because PEN film has a glass transition temperature of about 150 °C and softening of PEN occurs at elevated temperature.…”

Section: Introductionmentioning

confidence: 99%

In situ observation of ultrasonic flip-chip bonding using high-speed camera

Shuto

Asano

2015

Self Cite

“…In this work, we fabricate NIR image sensor using ultrasonic bonding of cone bumps. The ultrasonic bonding of cone bump makes it possible to realize a large number of inter-chip connections at room temperature [2,3]. To fabricate a NIR image sensor, an InGaAs photodiode array on an InP was stacked on Si CMOS readout IC by the cone bump.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, we have shown that the ultrasonic bonding of the cone bump offers room-temperature Au-Au bonding and Cu-Cu bonding. 29,30) However, the realization of a large number of interconnections such as a quarter video graphic array (qVGA) at room temperature is a challenge.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature bonding of heterogeneous materials for near-infrared image sensor

Shuto

Iwanabe

Ogura³

et al. 2014

Self Cite

Room temperature bonding technique using cone-shaped microbump with the aid of ultrasonic vibration is applied to fabrication of a near-infrared (NIR) image sensor. The image sensor is fabricated using chip-on-chip of InGaAs photodiode array on InP substrate and Si CMOS readout IC. The pixel pitch is 25 m to compose quarter-VGA class (320 × 256 pixels) resolution. A high quality imaging of heated object is demonstrated.