Investigation of low temperature Cu/In bonding in 3D integration

Hsieh, Y. F.; Shen, Tingting; Chien, Yu-San; Chen, Kuan‐Neng; Shinozaki, Yuko; Kawasaki, Naohiko

doi:10.1109/edssc.2015.7285131

Cited by 2 publications

(1 citation statement)

References 7 publications

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“…At room temperature, the stable phases in Cu-In binary system are Cu, , and In. Based on the previous experimental results and the Cu-In binary phase diagram, various IMCs (Cu7In3 (δ), Cu2In (η), Cu11In9, CuIn2, Cu16In9, and CuIn ) can appear during bonding [2], [3], [10]- [13], [16], [17], and phase transformation can occur during aging. Voids with different sizes appear after aging due to the volume shrinkage between different phases [15].…”

Section: Introductionmentioning

confidence: 90%

Utilizing Co as a contact metallization for wafer-level Cu-Sn-In SLID bonding used in MEMS and MOEMS packaging

Emadi

Vuorinen

Paulasto‐Kröckel

2022

2022 IEEE 9th Electronics System-Integration Technology Conference (ESTC)

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Many MEMS and MOEMS devices require hermetic packaging with preferably no postprocessing after the MEMS device's releasing. Wafer-level Solid-Liquid Interdiffusion (SLID) bonding can provide simultaneous hermetic packaging and better electrical interconnects. Moreover, employing a physically deposited contact metallization on the device wafer instead of chemically deposited layers (such as electrochemical Cu) is of utmost importance as far as reducing the complexity of the MEMS/MOEMS packaging process integration is concerned. The current work studied the possibility of utilizing Co as a contact metallization layer for the low-temperature Cu-Sn-Inbased SLID bonding. In order to guarantee the long-term reliability of the devices, a fundamental understanding of the formation and evolution of interconnection microstructures and mechanical characterization of the joint is of utmost importance. In this work, Cu-Sn-In electroplated Si chips were bonded to Co substrates at a temperature range 160-250°C. During the bonding process, a single intermetallic compound (IMC) (Cu,Co)6(Sn,In)5 formed at the bonding area, with no detectable Cu3Sn phase that causes voids formation. The Young's modulus and hardness of (Cu,Co)6(Sn,In)5 and Cu6Sn5, as a reference, were measured as 124.8±0.5 and 6.2±0.5, 114±1 and 6.7±0.5 MPa, respectively. Furthermore, the current study was able to produce a fully IMC joint of Cu-Sn-In/Co SLID system at 220°C for bonding time as short as 20 minutes.

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Section: Introductionmentioning

confidence: 90%

Utilizing Co as a contact metallization for wafer-level Cu-Sn-In SLID bonding used in MEMS and MOEMS packaging

Emadi

Vuorinen

Paulasto‐Kröckel

2022

2022 IEEE 9th Electronics System-Integration Technology Conference (ESTC)

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Characterization of low temperature Cu/In bonding for fine-pitch interconnects in three-dimensional integration

Panchenko

Bickel

Meyer

et al. 2017

Jpn. J. Appl. Phys.

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This study presents the results for Cu/In bonding based on the solid–liquid interdiffusion (SLID) principle for fine-pitch interconnects in three-dimensional integration. The microbumps were fabricated on Si wafers (55 µm pitch, 25 µm top bump diameter, 35 µm bottom bump diameter). In was electroplated directly on Cu only on the top die microbumps. Two different In thicknesses were manufactured (3 and 5 µm). The interconnects were successfully fabricated at a bonding temperature of 170 °C. High temperature storage was carried out at 150 and 200 °C for different times between 2 and 72 h directly after the interconnect formation in order to investigate the temperature stability. The microstructure was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The intermetallic compound (IMC) found in the microbumps after electroplating was CuIn2. The intermetallic interlayer consists of Cu11In9 and a thin layer of Cu2In after bonding and isothermal storage.

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Investigation of low temperature Cu/In bonding in 3D integration

Cited by 2 publications

References 7 publications

Utilizing Co as a contact metallization for wafer-level Cu-Sn-In SLID bonding used in MEMS and MOEMS packaging

Utilizing Co as a contact metallization for wafer-level Cu-Sn-In SLID bonding used in MEMS and MOEMS packaging

Characterization of low temperature Cu/In bonding for fine-pitch interconnects in three-dimensional integration

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