Thermosonic ball bonding: friction model based on integrated microsensor measurements

Schwizer, J.; Mayer, Michael; Bolliger, Daniel; Oliver, Paul; Baltes, H.

doi:10.1109/iemt.1999.804803

Cited by 29 publications

(18 citation statements)

References 2 publications

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“…2). More recently stress sensitive rosette patterns have been integrated onto silicon die to measure integrated circuit packaging stresses [238] Creatively, Schwizer et al used piezoresistive rosettes to measure wire bonding forces and flip chip solder ball process parameters [239], [240]. Planar arrangements of pseudo-hall effect strain sensors have also been demonstrated for 3D sensing when coupled with an input arm such as a joystick or coordinate measuring probes [59], [391].…”

Section: Devices and Applicationsmentioning

confidence: 99%

Review: Semiconductor Piezoresistance for Microsystems

et al. 2009

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Piezoresistive sensors are among the earliest micromachined silicon devices. The need for smaller, less expensive, higher performance sensors helped drive early micromachining technology, a precursor to microsystems or microelectromechanical systems (MEMS). The effect of stress on doped silicon and germanium has been known since the work of Smith at Bell Laboratories in 1954. Since then, researchers have extensively reported on microscale, piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors, including many commercially successful devices. In this paper, we review the history of piezoresistance, its physics and related fabrication techniques. We also discuss electrical noise in piezoresistors, device examples and design considerations, and alternative materials. This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.

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Section: Devices and Applicationsmentioning

confidence: 99%

Review: Semiconductor Piezoresistance for Microsystems

et al. 2009

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“…In addition, test chips can help to improve the reliability of a whole package [25]. Such microsensors were further used to determine a bonding force process window [76] or to get information about the bond growth during the dissipation of ultrasound [77,78]. Recently, several small piezoresistive sensors were integrated along a line below a bonding pad and read out during bonding a ball [79,80].…”

Section: Wire Bonding Importance and Recent Effortsmentioning

confidence: 99%

Microelectronic Bonding Processes Monitored by Integrated Sensors

Mayer¹,

Schwizer

2002

Sensors Update

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Real-time monitoring methods are beneficial for the control, optimization, and failure analysis of microelectronic packaging processes. The focus of this chapter is on the real-time monitoring of two widely used processes, soft solder die bonding and thermosonic ball bonding. The methods presented here use uniquely developed microsensors integrated on custom-made test chips using commercial double-metal CMOS processes.For the soft solder die bonding process, nine aluminum-based resistive temperature detectors were integrated on various locations on a test chip. The temperature was monitored during the placement of the test chip on the leadframe. The experimental results describe the wetting and spreading effects of the molten solder under the drip. Together with numerical results obtained with a transient thermal finite element model, the beginning of wetting can be quantified. For the soft solder PbSn10, wetting occurred around 30 ms after touch down. This method hence can be used to determine wetting times under different process conditions. The wetting time determines an upper limit of the throughput of the process.For the thermosonic ball bonding process, temperature and force sensors were integrated on test chips. The sensors are aluminum resistors and piezoresistive p + -and n + -diffused resistors placed around bond pads. A bond quality parameter can be derived from the temperature signal variation during bonding. The piezoresistive sensors permit the measurement of forces in the x-, y-, and z-directions simultaneously. The ultrasonic tangential force signal reached a typical value of 0.12 N on a 50 lm diameter contact zone and revealed significant process characteristics. Four process phases are identified which are necessary for a successful ball bond formation. These phases are assigned to initial stiction, sliding, bond growth, and deformation effects.

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“…Because the breakage sites of EFO wire are in the neck between the HAZ and the ball, it's clear that the structure of the neck zones and stress affecting the breakage sites result in the breakage [4][5][6][7]. In this research, the wire mechanical and electrical properties, the FAB (Free Air Ball), the HAZ were investigated.…”

Section: Introductionmentioning

confidence: 99%

Heat Affected Zone in the MEMS Wire Bonding

Liu

Sun

2009

2009 International Conference on Measuring Technology and Mechatronics Automation

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In the wire bonding process of MEMS packaging, Heat Affect Zone (HAZ) is the important factor governing the loop profile of bonding. The height of loop is affected by the length of the HAZ. Factors governing the HAZ are studied. To investigate this relationship, the experiments were done for the various sizes of wire diameter and Free Air Ball (FAB). Electric Flame-Off (EFO) current, EFO time, EFO gap and the recrystallization were also studied. The results showed that as the size of FAB became larger, the length of HAZ increased. With the increase of EFO current and time, the length of HAZ became longer. When FAB was formed at the same parameter, the length of HAZ became shorter with the high temperature of recrystallization. Keywords-heat affected zone; mems; wire bonding; free air ballI.

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Thermosonic ball bonding: friction model based on integrated microsensor measurements

Cited by 29 publications

References 2 publications

Review: Semiconductor Piezoresistance for Microsystems

Review: Semiconductor Piezoresistance for Microsystems

Microelectronic Bonding Processes Monitored by Integrated Sensors

Heat Affected Zone in the MEMS Wire Bonding

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