Process advantages of thermosonic wedge-wedge bonding using dosed tool heating

2019 ◽  
Vol 2019 (1) ◽  
pp. 000519-000523
Author(s):  
Matthias Hunstig ◽  
Andreas Unger ◽  
Michael Brökelmann ◽  
Hans J. Hesse
Keyword(s):  
Copper Wire ◽  
Wire Bonding ◽  
Process Time ◽  
Power Semiconductors ◽  
Positive Effects ◽  
Major Disadvantage ◽  
Ultrasonic Wire Bonding ◽  
Laser Heated ◽  
Wedge Bonding ◽  
Thermosonic Wire Bonding

Abstract Thermosonic wire bonding has a number of advantages over “cold” ultrasonic wire bonding. Despite these potential advantages, it is rarely used besides ball-wedge and gold wedge-wedge applications, mostly due to the drawbacks and limitations of available heating technology. A recently introduced novel thermosonic process using a laser-heated bonding tool avoids most of these drawbacks. This contribution presents the results of two series of bonding tests which have used this novel process to bond aluminium and copper heavy wire to sheets of the same metal. The bond test results prove that thermosonic wedge-wedge bonding with a laser-heated tool has a number of significant advantages in both aluminium and copper wire bonding. It can be used to reduce the process time, to decrease the mechanical stress in the substrate by reducing ultrasound vibration amplitude and/or normal force, and to increase bond strength. These advantages are the same as in classic thermosonic wire bonding, but without the major disadvantage of having to heat to whole package. Because of the high thermal conductivity and capacity of the investigated metal sheet substrates, the observed positive effects of a heated tool are expected to be significantly higher on real-world substrates such as power semiconductors.

Cell Interconnections in Battery Packs Using Laser-assisted Ultrasonic Wire Bonding

2020 ◽  
Vol 2020 (1) ◽  
pp. 000217-000221
Author(s):  
Andreas Unger ◽  
Matthias Hunstig ◽  
Michael Brökelmann ◽  
Dirk Siepe ◽  
Hans J. Hesse
Keyword(s):  
Bond Strength ◽  
Copper Wire ◽  
Wire Bonding ◽  
Process Time ◽  
Coated Steel ◽  
Major Disadvantage ◽  
Battery Packs ◽  
Mechanical Bond ◽  
Aluminium Wire ◽  
Ultrasonic Wire Bonding

Abstract This paper presents the results of a series of bonding tests using a laser-assisted ultrasonic wire bonding process. Aluminium and copper wire, both 500 μm (20 mil) thick, were bonded to nickel-coated steel caps of type 21700 battery cells. Mechanical bond strength tests prove that laser-assisted wire bonding has significant advantages over room temperature wire bonding. For example, it can be used to reduce the process time with aluminium wire or to increase the bondability of copper wire on nickel-coated steel. The results show a direct relation between tool tip temperature and measured bond strength. The quality of the joints was effectively improved by heating the tool tip up to 430 °C. These advantages are the same as in classic thermosonic wire bonding, but without the major disadvantage of having to heat to whole package. The cell temperature was shown to remain safely below the critical 60 °C in any application.

Copper wire bonding ready for industrial mass production

2015 ◽  
Vol 2015 (1) ◽  
pp. 000399-000405 ◽  
Author(s):  
M. Brökelmann ◽  
D. Siepe ◽  
M. Hunstig ◽  
M. McKeown ◽  
K. Oftebro
Keyword(s):  
Tool Wear ◽  
Copper Wire ◽  
Tool Material ◽  
Wire Bonding ◽  
Bond Quality ◽  
Process Data ◽  
Power Semiconductors ◽  
Bonding Parameters ◽  
Copper Wire Bonding ◽  
The Impact

Copper wire as a bonding material for the top side connection of power semiconductors is highly desired. One current drawback in heavy copper wire bonding is the relatively low lifetime of the consumables. The bonding tool wear mechanisms and the corresponding factors are investigated. To reduce wear, different approaches are tested in long-term bonding tests. Optimized bonding tool tip geometry and tool material are two of these factors. Optimized bonding parameters were investigated as well and show a significant improvement in bonding tool lifetime. Wear and lifetime of the cutter and the wire guide are also examined. Additionally, the impact of bonding tool wear on different aspects of bond quality is addressed. It is also shown how wear can be monitored by machine process data recording and how a derived signal correlates to the actual wear status. These major advances in heavy copper wire bonding now make it a robust, reliable and efficient interconnection technology.

Intelligent Production of Wire Bonds using Multi-Objective Optimization – Insights, Opportunities and Challenges

2018 ◽  
Vol 2018 (1) ◽  
pp. 000572-000577
Author(s):  
Andreas Unger ◽  
Matthias Hunstig ◽  
Tobias Meyer ◽  
Michael Brökelmann ◽  
Walter Sextro
Keyword(s):  
Process Model ◽  
Copper Wire ◽  
Stable Process ◽  
Wire Bonding ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Aluminium Wire ◽  
Process Disturbances ◽  
Ultrasonic Wire Bonding ◽  
Parameter Values

Abstract Ultrasonic wire bonding is an indispensable process in the industrial manufacturing of semiconductor devices. Copper wire is increasingly replacing the well-established aluminium wire because of its superior electrical, thermal and mechanical properties. Copper wire processes differ significantly from aluminium processes and are more sensitive to disturbances, which reduces the range of parameter values suitable for a stable process. Disturbances can be compensated by an adaption of process parameters, but finding suitable parameters manually is difficult and time-consuming. This paper presents a physical model of the ultrasonic wire bonding process including the friction contact between tool and wire. This model yields novel insights into the process. A prototype of a multi-objective optimizing bonding machine (MOBM) is presented. It uses multi-objective optimization, based on the complete process model, to automatically select the best operating point as a compromise of concurrent objectives.

Real-Time Observation of Interface Relative Motion during Ultrasonic Wedge-Wedge Bonding Process

2015 ◽  
Vol 2015 (1) ◽  
pp. 000419-000424 ◽  
Author(s):  
Yangyang Long ◽  
Jens Twiefel ◽  
Joscha Roth ◽  
Jörg Wallaschek
Keyword(s):  
Relative Motion ◽  
High Speed ◽  
Window Size ◽  
Frame Rate ◽  
Process Time ◽  
The Wire ◽  
Time Observation ◽  
Lower Frame ◽  
Ultrasonic Wire Bonding ◽  
Wedge Bonding

As a predominant interconnection technique in microelectronic industry, ultrasonic wire bonding has been investigated for decades ever since its invention. Due to the extremely short process time, high operating frequency and ultrathin interfaces, many mechanisms are still unknown. One focus point of the research is the motion behaviors at the two interfaces – interface between wire & substrate (wire/substrate) and interface between wire & bonding tool (wire/tool). In this project, the motion behaviors at the two interfaces were observed by a high speed camera combined with an optical magnification system. The relative motion at the wire/substrate interface was recorded at maximum a frame rate of 350,515 fps which is approximately six times higher than the bonding frequency. The relative motion is caused by the vibration induced reciprocal motion and the plastic deformation induced material flow. The wire/tool interface was observed at lower frame rates due to the window size confinement. Through the observations, a relative motion was captured for the first time. This discovery indicates that the process parameters must be carefully controlled so that cratering as well as other damaging problems can be avoided.

Failure Analysis on Power Trench MOSFET Devices with Copper Wire Bonds

2011 ◽  
Author(s):  
Huixian Wu ◽  
Arthur Chiang ◽  
David Le ◽  
Win Pratchayakun
Keyword(s):  
Failure Analysis ◽  
Copper Wire ◽  
New Technology ◽  
Analytical Techniques ◽  
Wire Bonding ◽  
Bonding Process ◽  
Wire Bonds ◽  
Copper Wire Bonding ◽  
Wet Chemical ◽  
Microelectronic Components

Abstract With gold prices steadily going up in recent years, copper wire has gained popularity as a means to reduce cost of manufacturing microelectronic components. Performance tradeoff aside, there is an urgent need to thoroughly study the new technology to allay any fear of reliability compromise. Evaluation and optimization of copper wire bonding process is critical. In this paper, novel failure analysis and analytical techniques are applied to the evaluation of copper wire bonding process. Several FA/analytical techniques and FA procedures will be discussed in detail, including novel laser/chemical/plasma decapsulation, FIB, wet chemical etching, reactive ion etching (RIE), cross-section, CSAM, SEM, EDS, and a combination of these techniques. Two case studies will be given to demonstrate the use of these techniques in copper wire bonded devices.

scholarly journals Development of high reliability semiconductor devices by copper wire bonding.

1988 ◽  
Vol 27 (4) ◽  
pp. 299-301
Author(s):  
J. Hirota ◽  
Y. Shibutani ◽  
T. Sugimura ◽  
K. Machida ◽  
T. Okuda
Keyword(s):  
High Reliability ◽  
Copper Wire ◽  
Semiconductor Devices ◽  
Wire Bonding ◽  
Copper Wire Bonding

Modeling and Experimental Study of a Wire Clamp for Wire Bonding

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Fuliang Wang ◽  
Dengke Fan
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Energy Conservation ◽  
Design Process ◽  
Gold Wire ◽  
Wire Bonding ◽  
Fe Model ◽  
Amplification Ratio ◽  
Model Studies ◽  
Thermosonic Wire Bonding

A wire clamp is used to grip a gold wire with in 1–2 ms during thermosonic wire bonding. Modern wire bonders require faster and larger opening wire clamps. In order to simplify the design process and find the key parameters affecting the opening of wire clamps, a model analysis based on energy conservation was developed. The relation between geometric parameters and the amplification ratio was obtained. A finite element (FE) model was also developed in order to calculate the amplification ratio and natural frequency. Experiments were carried out in order to confirm the results of these models. Model studies show that the arm length was the major factor affecting the opening of the wire clamp.

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