Suppression of Interdiffusion in Copper/Tin Thin Films

Etschmaier, Harald; Torwesten, Holger; Eder, H.; Hadley, P.

doi:10.1007/s11665-011-0090-2

Cited by 10 publications

(6 citation statements)

References 10 publications

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“…To assure a bondline with defined layers of Au-In IMCs, a slow temperature ramping of 2°C/min during heating was chosen, in accordance with Aasmundtveit et al (2016). This ensures initial IMC layer formation while the temperature is still below the melting temperature, and further, IMC growth is in the form of layers instead of scallops (Peng et al, 2007;Etschmaier et al, 2012).…”

Section: Bondingmentioning

confidence: 99%

In–Bi low-temperature SLID bonding for piezoelectric materials

Aasmundtveit

Eggen

Manh

et al. 2018

SSMT

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Purpose This paper aims to demonstrate low-temperature bonding for piezoelectric materials at temperatures well below the relevant Curie temperatures so as to avoid depolarization of the piezoelectric material during bonding. Design/methodology/approach Au-coated test samples of lead zirconate titanate (PZT) are bonded to a WC-based resonant backing layer with In–Bi eutectic material in which the In–Bi metal system is a preform or thin, evaporated layers. The bonded samples are characterized using electrical impedance spectroscopy and cross-section microscopy. The first technique verifies the integrity of polarization and reveals the quality of the bondline in a non-destructive manner, particularly looking for voids and delaminations. The latter technique is destructive but gives more precise information and an overview of the structure. Findings Successful low-temperature (115°C) bonding with intact PZT polarization was demonstrated. The bondlines show a layered structure of Au/Au–In intermetallic compounds (with Bi inclusions)/Au, capable of withstanding temperatures as high as 271°C before remelting occurs. For bonded samples using In–Bi preform, repeatable bonds of high quality (very little voiding) were obtained, but the bonding time is long (1 h or more). For bonded samples using evaporated thin films of In–Bi, bonding can be performed in 30 min, but the process needs further optimization to be repeatable. Originality/value Low-temperature solid-liquid interdiffusion (SLID) bonding is a novel technique, merging the fields of low-temperature solder bonding with the SLID/transient liquid phase (TLP) approach, which is normally used for much higher temperatures.

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Section: Bondingmentioning

confidence: 99%

In–Bi low-temperature SLID bonding for piezoelectric materials

Aasmundtveit

Eggen

Manh

et al. 2018

SSMT

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“…Usually, a short holding time is introduced in the bonding profile, at a temperature before the melting temperature of the low-melting metal is reached. This ensures initial formation of a uniform layer of IMC by solid-state diffusion, which is a key factor for obtaining uniform growth of IMC layers during isothermal solidification, crucial for minimizing void formation in the bondline [18]. All our SLID bonding is flux-free, eliminating the need for post-bond cleaning and allowing SLID bonds to be used for vacuum encapsulation without risking residual flux jeopardizing vacuum levels.…”

Section: Bondingmentioning

confidence: 99%

Solid-Liquid InterDiffusion (SLID) Bonding, for Thermally Challenging Applications

Aasmundtveit

Luu²,

Nguyen

et al. 2019

2019 IEEE 69th Electronic Components and Technology Conference (ECTC)

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…This controls diffusion through the solid IMC also when the low-melting point metal is melted. If the temperature is raised to the melting point without this interface IMC formed, the system is prone to scallop growth of IMCs, with voids in the bond-line as a result [13,14].…”

Section: Bonding Profilesmentioning

confidence: 99%

Intermetallic Bonding for High-Temperature Microelectronics and Microsystems: Solid-Liquid Interdiffusion Bonding

Aasmundtveit¹,

Luu²,

Nguyen³

et al. 2018

Intermetallic Compounds - Formation and Applications

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Solid-liquid interdiffusion (SLID) bonding for microelectronics and microsystems is a bonding technique relying on intermetallics. The high-melting temperature of intermetallics allows for system operation at far higher temperatures than what solder-bonded systems can do, while still using similar process temperatures as in common solder processes. Additional benefits of SLID bonding are possibilities of fine-pitch bonding, as well as thin-layer metallurgical bonding. Our group has worked on a number of SLID metal systems. We have optimized wafer-level Cu-Sn SLID bonding to become an industrially feasible process, and we have verified the reliability of Au-Sn SLID bonding in a thermally mismatched system, as well as determined the actual phases present in an Au-Sn SLID bond. We have demonstrated SLID bonding for very high temperatures (Ni-Sn, having intermetallics with melting points up to 1280°C), as well as SLID with low process temperatures (Au-In, processed at 180°C, and Au-In-Bi, processed at 90-115°C). We have verified experimentally the high-temperature stability for our systems, with quantified strength at temperatures up to 300°C for three of the systems: Cu-Sn, Au-Sn and Au-In.Keywords: microelectronics/microsystem assembly, bonding technology, harsh environments, wafer processing, reliability, transient liquid phase © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Motivation for SLID The challenge of die attach and interconnectionFor all electronic systems, the attachment of components to substrates and their electrical connection is a crucial part of the system. Traditionally, the processes for attachment and interconnection have been considered more a craft than a science. The historical focus of electronics and microtechnology has been on the design, manufacturing and testing of components, circuits and devices, rather than on the system integration and the processes needed for actually building the system. The 'electronic revolution' has given ever-increasing performance of devices at ever-decreasing prices for more than half a century. Initial milestones were the invention of the transistor (1947) and the integrated circuit (IC) (1958). The driving factor has been a continuous decrease in size (of components and on features of components) and cost, made possible through batch processing of silicon wafers. Single-crystal silicon is a very well-defined material with extremely well-characterized properties, allowing process technology that yields extremely small features (10 nm by 2017, with a further decrease expected). Miniaturization of components and the use of large Si wafers give a huge number of components manufactured in every batch, lowering the cost. Furthermore, miniaturization allows an increase in operating frequency (or a decrease...

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Suppression of Interdiffusion in Copper/Tin Thin Films

Cited by 10 publications

References 10 publications

In–Bi low-temperature SLID bonding for piezoelectric materials

In–Bi low-temperature SLID bonding for piezoelectric materials

Solid-Liquid InterDiffusion (SLID) Bonding, for Thermally Challenging Applications

Intermetallic Bonding for High-Temperature Microelectronics and Microsystems: Solid-Liquid Interdiffusion Bonding

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