Precise flip chip assembly using electroplated AuSn20 and SnAg3.5 solder

Hütter, Matthias; Oppermann, Hermann; Engelmann, G.; Dietrich, Lothar; Reichl, H.

doi:10.1109/ectc.2006.1645789

Cited by 20 publications

(10 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When solid-state diffusion occurs between Au/Sn interface, the diffusion rate of Au in Sn is two orders of magnitude faster in gold (Yamada et al, 2005;Hutter et al, 2006). The Kirkendall holes can be found on the Au side of Au/Sn-5Sb-1Cu-0.1Ni-0.1Ag/(Au)Ni joint shown in Point A in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging

Han

Sun

et al. 2019

SSMT

View full text Add to dashboard Cite

Purpose The purpose of this paper is to investigate the morphology evolution and the composition transformation of Au-Sn intermetallic compounds (IMCs) of the new Au/Sn-5Sb-1Cu-0.1Ni-0.1Ag/(Au)Ni solder joint during the high temperature aging. Design/methodology/approach Sn-5Sb-1Cu-0.1Ni-0.1Ag solder balls (500 µm in diameter), heat sink with structure of 7.4 µm Au layer on 5 µm Ni-plated Cu alloy and Si chip with 5.16 µm plated Au were used to fabricate micro-solder joints. The joints were performed in a furnace at 150°C for 150, 250 and 350 h aging. The samples were polished and deep etched before analyzed by metallographic microscope and scanning electron microscopy, respectively. Energy dispersive x-ray spectroscopy was used to identify the composition of the IMCs. Findings ß-(Au,Ni,Cu)10Sn phase is formed during the soldering process. The IMCs evolution has two periods during the aging. The first is the ξ-(Au,Ni,Cu)5Sn, ξ-(Au,Cu)5Sn and δ-AuSn were formed and grew to form a full-compound joint after about 150 h aging. The second is the conversion of the full-compound joint. The IMCs converted to ξ′ phase when the aging time extends to 250 h, and transformed to ε-(Au,Ni,Cu)Sn2 and η-(Au,Ni,Cu)Sn4 after 350 h aging. The thicker gold layer and thinner solder joint can promote the growth of the IMCs. ß-(Au,Ni,Cu)10Sn emerged in Au/SnSb-CuNiAg/(Au)Ni in this research, which is not usually found. Originality/value The results in this study have a significant meaning for the application of the new Sn-5Sb-1Cu-0.1Ni-0.1Ag in harsh conditions.

show abstract

Section: Resultsmentioning

confidence: 99%

Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging

Han

Sun

et al. 2019

SSMT

View full text Add to dashboard Cite

show abstract

“…Bump structures consisting of a gold (Au)-tin (Sn) multilayer were introduced onto four top electrode pads of each pMUT to enable future integration with a CMOS chip [31][32][33]. Integration with CMOS allows for a large number of pMUT elements with improved amplification, high signal strength, low power consumption, and compact size [34]. The microstructure and crystallinity of the AlN were analyzed to evaluate the quality of the thin film.…”

Section: Introductionmentioning

confidence: 99%

“…Square-shaped Au-Sn bumps (20 × 20 µm 2 ) were deposited on the electrode pads and AlN pillar before the backside silicon etching process. Au-Sn multilayers display good stability and thermal cycling ability, and excellent fatigue resistance when used for eutectic bonding of integrated circuits [33,34]. To achieve the eutectic composition of Au and Sn (80 and 20 wt%, respectively) [33], a 10-nm-thick titanium (Ti) adhesion layer, 800-nm-thick Au layer, 300-nm-thick Sn layer, and 20-nm-thick Au cap passivation layer were continuously sputtered without breaking the vacuum using a multitarget RF magnetron sputter system.…”

Section: Introductionmentioning

confidence: 99%

Development of a High-Density Piezoelectric Micromachined Ultrasonic Transducer Array Based on Patterned Aluminum Nitride Thin Film

et al. 2020

View full text Add to dashboard Cite

This study presents the fabrication and characterization of a piezoelectric micromachined ultrasonic transducer (pMUT; radius: 40 µm) using a patterned aluminum nitride (AlN) thin film as the active piezoelectric material. A 20 × 20 array of pMUTs using a 1 µm thick AlN thin film was designed and fabricated on a 2 × 2 mm2 footprint for a high fill factor. Based on the electrical impedance and phase of the pMUT array, the electromechanical coefficient was ~1.7% at the average resonant frequency of 2.82 MHz in air. Dynamic displacement of the pMUT surface was characterized by scanning laser Doppler vibrometry. The pressure output while immersed in water was 19.79 kPa when calculated based on the peak displacement at the resonant frequency. The proposed AlN pMUT array has potential applications in biomedical sensing for healthcare, medical imaging, and biometrics.

show abstract

“…A fundamental issue in photonic components is the accurate positioning and there are reports which show passive assembly for laser modules using the self-alignment of solders with mechanical stops [4][5][6][7] Our goal is to use edge facet laser chips and optical alignment between a laser chip and a nanophotonic chip, which requires sub-micron accuracy in three dimensions. There are therefore substantial challenges to overcome in using solder reflow for edge facet laser assembly on Si nanophotonic chips.…”

Section: Introductionmentioning

confidence: 99%

Flip chip assembly with sub-micron 3D re-alignment via solder surface tension

Nah

Martin

Kamlapurkar

et al. 2015

2015 IEEE 65th Electronic Components and Technology Conference (ECTC)

View full text Add to dashboard Cite

We demonstrate experimentally a flip-chip assembly with submicron three-dimensional alignment accuracy. We employ solder surface tension to push the flipped chip into lithographically defined alignment stops. During reflow, surface tension forces of the melted solder can move a chip by more than a hundred microns. We use these motions to obtain self-alignment by constraining the motions to lithographically defined mechanical stops and chip edge butting. This approach is particularly useful in InP laser to Si photonic assemblies, where sub-micron alignment is required for low optical connection loss. In this report, our test vehicles comprise silicon photonic chips and laser placeholder chips made of silicon as well. To enable self-alignment of edgeemitting single-mode lasers, a significant re-alignment range is needed to overcome the laser cleaving tolerance of +/-15 microns and the low +/-10 microns placement accuracy of high-throughput pick-and-place tools. We employ in-situ infrared (IR) microscopy to look through the assembled chips during solder induced re-alignment. We show that the selfalignment of the chips starts at the moment the solders melt. Cross sectional analysis is used to confirm the alignment accuracy and contact on the lithographic stops. We discuss process window considerations related to standoff height and solder volume.978-1-4799-8609-5/15/$31.00 ©2015 IEEE

show abstract

Precise flip chip assembly using electroplated AuSn20 and SnAg3.5 solder

Cited by 20 publications

References 5 publications

Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging

Microstructure evolution of Au/SnSb-CuNiAg/(Au)Ni during high temperature aging

Development of a High-Density Piezoelectric Micromachined Ultrasonic Transducer Array Based on Patterned Aluminum Nitride Thin Film

Flip chip assembly with sub-micron 3D re-alignment via solder surface tension

Contact Info

Product

Resources

About