Effect of Different Oxide Layers on the Ultrasonic Copper Wire Bond Process

Eacock, Florian; Unger, Andreas; Eichwald, Paul; Grydin, Olexandr; Hengsbach, Florian; Althoff, Simon; Schaper, Mirko; Guth, Karsten

doi:10.1109/ectc.2016.91

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Coatings 2024, 14, x FOR PEER REVIEW 2 of 20 steel used for cylindrical battery shell production in the aluminum wire bonding process are not widely available. Methods of surface preparation include mechanical cleaning with solvents [11], laser cleaning [12][13][14], CO2 cleaning [15], and plasma cleaning [16]. Cleaning with solvents and chemicals is a lengthy process not suitable for large-scale production.…”

Section: Methodsmentioning

confidence: 99%

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Influence of Cylindrical Cells Surface Cleaning by Means of Laser Ablation on Wedge Wire Bonding Process

Bieliszczuk,

Zręda,

Chmielewski

2024

Coatings

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Wire bonding is a method of connecting two or more surfaces by the means of a thin wire which is ultrasonically bonded to those surfaces and provides an electrical connection. While this method is well established in the microelectronics industry its popularity is rising in the area of cylindrical lithium-ion battery pack manufacturing. Previous studies have shown that even in experimental conditions this process might be unstable which was indicated by the high standard deviation of the bonds shear test results. This might have been related to contamination of the interface area between the joined materials. The aim of this study was to determine the impact of surface laser cleaning on the properties of the wire-bonded joint. The results have shown that laser cleaning with 40% power of the 30 W ATMS4060 laser marker helps to reduce the standard deviation of the shear test results from 16.1% for the uncleaned sample down to 2.6% and greatly reduces the number of oxides within the interface area of the bond cross section. Cleaning with 80% of the laser power did not have a further impact on shear test results and almost completely eliminated oxides from the bonded materials interface.

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Section: Methodsmentioning

confidence: 99%

“…Methods of surface preparation include mechanical cleaning with solvents [11], laser cleaning [12][13][14], CO 2 cleaning [15], and plasma cleaning [16]. Cleaning with solvents and chemicals is a lengthy process not suitable for large-scale production.…”

Section: Introductionmentioning

confidence: 99%

Influence of Cylindrical Cells Surface Cleaning by Means of Laser Ablation on Wedge Wire Bonding Process

Bieliszczuk,

Zręda,

Chmielewski

2024

Coatings

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“…The natural oxide-layers of copper material of the bonding partners pin and substrate have an influence on the bond quality [12]. It is well known, that in wire bonding a high plastic strain in the contact zone due to material softening has a positive effect on surface cleaning and consequently on surface activation [14].…”

Section: Plasticizing Of Connector Pinmentioning

confidence: 99%

Multi-dimensional Ultrasonic Copper Bonding – New Challenges for Tool Design

Eichwald

Althoff

Schemmel

et al. 2017

International Symposium on Microelectronics

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In power electronics, copper connector pins are e.g. used to connect control boards with power modules. The new chip generation based on SiC and GaN technology increase the power density of semiconductor modules significantly with junction temperatures reaching 200°C. To enable reliable operation at such high temperature, the soldering of these connector pins should be substituted by a multi-dimensional copper-copper bonding technology. A copper pin welded directly on DBC substrate also simplifies the assembly. With this aim, a proper bond tool and a suitable connector pin geometry are designed. This paper presents a two-dimensional trajectory approach for ultrasonic bonding of copper pieces, e.g. connector pins, with the intention to minimize mechanical stresses exposed to the substrate. This is achieved using a multi-dimensional vibration system with multiple transducers known from flip chip bonding. Applying a planar relative motion between the bonding piece and the substrate increases the induced frictional power compared to one-dimensional excitation. The core of this work is the development of a new tool design which enables a reliable and effective transmission of the multidimensional vibration into the contact area between nail-shaped bonding piece and substrate. For this purpose, different bonding tool as well as bonding piece designs are discussed. A proper bonding tool design is selected based on the simulated alternatives. This tool is examined in bonding experiments and the results are presented. In addition, different grades of hardness for bonding piece and substrate are examined as well as different bonding parameters. Optical inspection of the bonded area shows the emergence of initial micro welds in form of a ring which is growing in direction of the interface boundaries with increasing bonding duration.

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