China
Africa
Explore chapters and articles related to this topic
Interconnections and Connectors
Published in Michael Pecht, Handbook of Electronic Package Design, 2018
Three primary parameters affecting thermocompression bonding are force, temperature, and time. These parameters are interdependent and are affected by other conditions and factors. Minor changes in these variables can cause significant differences in the bond characteristics. Hence it is necessary to optimize the primary parameters to obtain a satisfactory bond. Short bonding time is desirable for production purposes. Low bonding temperature is desirable to avoid degradation of the wire bonds due to gold-aluminum interactions. Low pressures are desirable to avoid fracturing or otherwise damaging the silicon beneath the bond. Too large a force may damage the semiconductor substrate or deform the wire excessively, and too small a force may produce inadequate bonding. The wire in some cases may be weaker than the bond. In the ball bond, the weakest link occurs in the annealed wire leading to the bond. In the stitch and wedge bonds it occurs in the region of the wire in which the cross section has been reduced by the bonding tool. The bonding tool used in the process may be of tungsten carbide, titanium carbide, sapphire, and ceramics [5].
Interconnection Technology
Published in Yufeng Jin, Zhiping Wang, Jing Chen, Introduction to Microsystem Packaging Technology, 2017
Yufeng Jin, Zhiping Wang, Jing Chen
Thermocompression bonding involves the use of temperature and pressure to produce plastic deformation of metal on the bonding pad, as well as destroying the oxide layer on the interface of the metal bonding pad so as to make the interface of both bonded metal wire and bonded pad metal reach atomic attraction bond and realize bonding through the attraction force between atoms. In addition, the rough metal interface together with the use of temperature and pressure can help close embedding between the metals. This bonding process, however, may cause damage to metal wire from over-distortion, as well as affecting bond quality. This limitation restrains the use of thermocompression bonding.
Effect of anodizing on direct joining properties of aluminium alloy and plastic sheets by friction lap joining
Published in Welding International, 2018
Toshiya Okada, Shouhei Uchida, Kazuhiro Nakata
However, each of these methods has disadvantages. With joining by injection moulding, for instance, the use of a mould imposes large constraints on the product’s dimensions and shape. Mechanical fixing necessitates the use of secondary materials for rivets and bolts and so on, which can result in increases in weight and costs and also requires measures to ensure airtightness and watertightness, all of which constrain the design scope. When an adhesive is used for joining, the organic solvents that are used with epoxy and acrylic adhesives may cause health risks and are subject to VOC regulations (which regulate the emissions of volatile organic compounds). In addition to this, considerable time is needed for the required adhesive strength to be achieved during the adhesion process and the adhesion properties deteriorate after prolonged use, both these characteristics posing problems for practical use. Ultrasonic joining is also very limited as to the product dimensions and shape. Because of this, thermocompression bonding, a method by which large members can be directly joined with good adhesion and in which bonding is achieved with localized melting of the bonding interface by heating thermoplastic resin, has come under scrutiny and the range of heat sources for this, including high-frequency induction heating, resistance heating and laser heating, have been investigated.
Low-resistance copper conductive balls that prevented migration
Published in Journal of Information Display, 2022
Jong-Keun Choi, Young-Gyun Kim, Kwan-Young Han
A scanning electron microscope (SEM) was used to determine the surface uniformity and shape of the fabricated conductive balls, and energy dispersive spectrometry (EDS) was used to confirm the metal coating on the surface. Copper-coated conductive balls were used to prepare the ACF. The dimensions of the FPCB were 48 mm × 33 mm, and its electrode’s dimensions were 2 µm × 2 µm. The thickness and pitch of the FPCB were 10 and 20 µm, respectively. A sample was prepared through the thermocompression bonding of the ACF between the FPCB and indium tin oxide glass, and the contact resistance was measured by using a four-point probe. Finally, to measure reliability data, we maintained an internal environment at a temperature of 85°C and a humidity of 85% by using reliability equipment.