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Highly dynamic DC-machines, used in low power applications, often contain ironless or so called bell shaped windings. Because there is no massive iron core to support the windings, one of the limiting factors for the torque of the machine is the force on the single wires of the copper weave. Therefore, the knowledge of the force distribution on the single wires could be a helpful design criterion...
With the Copper wire bonding already occupying majority of production lines, there are many significant factors continue to surface out. The Copper wire bonding has also becomes very susceptible to production variability of small leaded packages such as Thin Small Outline Package (TSOP). The TSOP utilizes thin and flimsy leadframes, causing a lot challenges at 2nd bond (stitch). The stitch bonding...
Ultrasonic heavy wire bonding is a commonly used technology to conduct electrical devices in power electronics. In order to facilitate powerful solutions combined with an increased efficiency, involving a material change from aluminum to copper wire as conductor material takes place in recent years. Due to the material related properties, copper wire bonding requires significant higher bond processing...
Wire bonding has been an established packaging technology for decades. When introducing copper as wire material for high power applications, adaptations to the bonding process and to machines became necessary. Here, challenges occur due to the stiffer wire material and changing oxide layers on the contact partners. To achieve sufficient process stability, a clean bond area is required, which can only...
In this paper, a strategy to capture individual micrometal wires in air by ultrasound is demonstrated. Curved and flattened tip of a vibrating needle excited by a sandwich-type transducer, operating at about 45.8 kHz, is employed to capture micrometal wires in air. A 40-μm-diameter copper wire with a length of 1–14 mm can be trapped stably by ultrasound and transferred through any 3-D path in air...
Changing manufacturing technologies or material in well-known processes has to be followed by an adaption of process parameters. In case of the transition from aluminum wire to copper wire in heavy wire bonding, the adaption effort is high due to the strongly different mechanical properties of the wire. One of these adaption aspects, apart from wire material, is the existent oxide layers on wire and...
Within the manufacturing of electric drives, the joining of resin insulated copper wires with standardized tubular cable lugs has to be seen as an important manufacturing step, as this process is one major reason for drive malfunctions - especially in case of mobile devices. Currently, the thermo-crimping technique is commonly used, because it combines high process stability with short tact times...
This paper describes the nominal control system design to counter the effect of deployment of an electro-dynamic tether on a polar low-earth orbit nano-satellite. The complete tether assembly including the deployment mechanism, choice of material, length of the tether, preferred door axis for deployment of tether have been explained in detail. Analysis of the effect of deployment of the tether on...
During the surface mount technological process the assembled PCB is exposed to heat when molten solder alloy wets the surfaces and creates future solder joints. The PCB with all components should ideally be exposed to the same temperature profile during the soldering process. The temperatures differ throughout the PCB due to different thermal capacities of used materials and components even though...
In order to increase mechanical strength, heat dissipation and ampacity and to decrease failure through fatigue fracture, wedge copper wire bonding is being introduced as a standard interconnection method for mass production [1]. To achieve the same process stability when using copper wire instead of aluminum wire a profound understanding of the bonding process is needed. Due to the higher hardness...
In the study, the effects of Pd thickness on free air ball, wire elongation/strength on bonding strength and bonding interface of Pd coated copper wire bonding were discussed. It was found that the Pd thickness effects on free air ball, the free air ball will become golf ball when the Pd thickness is thin excessively, then the Pd thickness is not less than 0.47% to the wire diameter, and high tensile...
Copper wire has been popular in these years when facing ever-increasing gold prices. Recently, Pd-coated Cu wire is emerging as an alternative to bonding with bare Cu wire to prevent copper oxidation during the bonding and improve manufacturability. In recent years, many papers were published focusing on KNS bonder platform development. KNS became more and more popular in copper wire bonding field,...
In this paper, the copper property under various ultrasonic powers was firstly investigated by experiment. It is found the ultrasound has an acoustic softening effect on copper free air balls (FABs). The stressstrain behavior of copper FABs that accounted for acoustic softening effect was achieved by combining experiment and numerical simulation. Then a non-linear finite element (FE) model was built...
Driven by applications in the field of renewable energy, power distribution, consumer electronics and the automotive industry, the demand for reliable and economic power electronics packaging solutions is growing rapidly. The present study aims to display a new technology for chip top-side interconnects by using heavy wire copper wedge/wedge bonding. Therefore a response surface design of experiment...
Copper wire has been popular in these years when facing ever-increasing gold prices. Recently, Pd-coated Cu wire is emerging as an alternative to bonding with bare Cu wire to prevent copper oxidation during the bonding and improve manufacturability. Compared to bare copper, Pd copper wire shows robust bonding process, especially offers 2nd bond and better reliability. When it comes to 1st bond, it...
Palladium coated Copper (PCC) bonding wire is a popular low cost alternative for Gold wire. The quality of an innovative Pd coating technique on Cu (Direct PCC) wire is evaluated by comparing free air ball (FAB) deformability and stitch bond strength to those of Cu wire. The coating is applied to commercial Cu wire which is either thermally treated or as-delivered. FABs of 40 μm diameter are produced...
In this paper, we will compare Cu wire and Au wire behavior during pull test and package reliability test through thermo-mechanical simulation. Relationship between wire pull test and package reliability test, i.e. thermal cycling, is also evaluated in term of die stress underneath the wire bond pad area. A new stress index concept is proposed to characterize the overall die stress level underneath...
Gold wire bonding is widely used as the electrical connection or interconnection between the semiconductor component (die) and the package. Bond pads pitch on the device chips are reducing continuously as device technology is moving towards nano-IC technologies. Gold wire is not suitable in the case where the bond pad pitch is less than 50µm because of gold's lower intensity and stiffness [1]. Recently,...
Wire bonding technology has been widely used in the semiconductor industry for interconnection between device and substrate. Gold wire has been used in industry for many years; however with the increase in the price of gold in the past few years, copper wire has become an alternative. Copper wires have better electrical and thermal performance than gold wire. However due to coppers hardness, the bonding...
Copper wire bonding is being developed rapidly in recent years to replace expensive gold wire for electronic packaging. However, one issue about reliability in humidity environment causes risk in its application. The copper wire-aluminum pad interface degradation usually leads to electrical open failure. Present paper studied all the 5 factors including pad finish of chip, molding compound, wire bonding...
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