Au Bump Interconnection with Ultrasonic Flip-Chip Bonding in 20 µm Pitch

Tanida, Kazumasa; Umemoto, Mitsuo; Tomita, Yoshihiro; Tago, Masamoto; Kajiwara, Ryoichi; Akiyama, Yukiharu; Takahashi, Kenji

doi:10.1143/jjap.42.2198

Cited by 57 publications

(18 citation statements)

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“…Among the various forms of the SiP, the stacked three-dimensional SiP, which forms penetrating electrodes through the chip and connects the upper and lower chips by narrow-pitch bumps of Au or Cu, is suited for high-speed operation, and thus has been actively studied [5][6][7]. In a three-dimensional stacked SiP, the chips to be stacked should be thinned to a thickness of several dozen micrometers, considering the wiring resistance of the penetrating electrode and the height of the package.…”

Section: Introductionmentioning

confidence: 99%

Mobility change of MOSFETs in a chip-stacked multichip package

Ikeda¹,

Honda²,

Ogi³

et al. 2006

Electron. Comm. Jpn. Pt. II

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We studied the mobility change of MOSFETs in a chip‐stacked multichip package. A 6‐inch wafer that had the back ground to 50 µm thickness was diced into chips and a chip was cemented to a glass epoxy substrate with a nonconductive paste (NCP), and in addition, a second chip was bonded on the first chip in a flip chip arrangement. The interchip connection was made by thermocompression bonding of Au/Ni bumps formed on the upper and lower chips. The MOSFETs on the first chip had not shown changes in mobility before stacking the second chip, but after stacking the chip, the mobility of the pMOSFETs increased and the mobility of the nMOSFETs decreased. Before chip stacking, the first chip had been slightly convex, but after stacking it was deformed to a greatly concave shape. It is considered that the glass epoxy substrate or the NCP had undergone a plastic deformation during the thermocompression bonding of the chip and that the strain from this deformation remained after the thermocompression bonding process. As a consequence, bending compressive stress occurred in the first chip in the [1¯10] direction, and it is considered that the mobility of the MOSFET changed due to the piezoresistive effect. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(7): 1– 8, 2006; Published online in Wiley InterScience (http://www.interscience.wiley.com). DOI 10.1002/ecjb.20246

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Section: Introductionmentioning

confidence: 99%

Mobility change of MOSFETs in a chip-stacked multichip package

Ikeda¹,

Honda²,

Ogi³

et al. 2006

Electron. Comm. Jpn. Pt. II

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“…(23) Ultrasonic bonding is also an effective method because of its advantages of rapid bonding and low-temperature process. (24)(25)(26) The low-temperature Cu-Cu bonding of conventional bumps in ambient air has been investigated using ultrasonic assist with surface treatments. (27) On the other hand, we have developed metallic compliant bumps that are easier to deform than conventional bumps.…”

Section: Introductionmentioning

confidence: 99%

Room-temperature Hermetic Packaging Using Ultrasonic Cu?Cu Bonding with Compliant Rim

Takigawa

Iwanabe

Ikeda

et al. 2018

Sensors and Materials

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In this paper, hermetic packaging using room-temperature (RT) Cu-Cu bonding is demonstrated for microsystem packaging. The bonding of the compliant rim made of Cu to electroplated Cu was performed with ultrasonic assist at RT. Owing to the cone-shaped cross section of the compliant rim, it easily deforms under pressing load with ultrasonic assist and bonds to the counter Cu film at RT. As a result of a simple vacuum test, the air leak rate of the cavity inside the bonded sample was approximately 2 × 10 −11 Pa•m 3 /s, which may be sufficiently low for applications of vacuum packaging of microdevices.

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“…The problem is that an actual bonding surface consists of an oxide film and a machined layer; [3][4][5][6][7] therefore, adhesion between surfaces at the bond interface and removal of the oxide film represent necessary requirements to obtain high bond strength. Recently, ultrasonic vibration, [8][9][10][11][12][13] plasma processing, [14][15][16][17][18][19] and organic acid pretreatment [20][21][22][23] have been investigated as methods for breaking and cleaning a superficial oxide film. Indeed, in a previous study, we showed that modification of an oxide film with formic acid greatly improves the strength of bonding between tin surfaces 22) and between tin and copper.…”

Section: Introductionmentioning

confidence: 99%

Cu/Cu direct bonding by metal salt generation bonding technique with organic acid and persistence of reformed layer

Koyama

Hagiwara

Shohji

2015

Jpn. J. Appl. Phys.

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In this study, the effect of the metal salt generation bonding technique on the strength of a direct-bonded copper–copper interface was investigated. Copper surfaces were modified by boiling in several types of organic acids, and direct bonding was performed at a bonding temperature of 423–673 K under a load of 588 N (for a bonding time of 0.9 ks). As a result of the surface modification, bonded joints were obtained at bonding temperatures of 150 K (after treatment with formic acid) and 100 K (after citric acid treatment) lower than that required for the unmodified surfaces. In addition, the duration of the modification effects was investigated by exposing the modified surface to an air atmosphere furnace kept at 323 K. The bonding strength of the citric acid-modified surface remained unchanged even after 168 h, whereas that of the surface modified with formic acid decreased within 6 h.

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Au Bump Interconnection with Ultrasonic Flip-Chip Bonding in 20 µm Pitch

Cited by 57 publications

References 0 publications

Mobility change of MOSFETs in a chip-stacked multichip package

Mobility change of MOSFETs in a chip-stacked multichip package

Room-temperature Hermetic Packaging Using Ultrasonic Cu?Cu Bonding with Compliant Rim

Cu/Cu direct bonding by metal salt generation bonding technique with organic acid and persistence of reformed layer

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