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Assembly Techniques
Published in Roydn D. Jones, Hybrid Circuit Design and Manufacture, 2020
Three processes are required for a tape carrier system. The first is the fabrication of the tape carrier and lead frame. The tape is most often a polyimide film with copper laminated to the surface. The lead frame pattern is created by photolithographic processing and etching. Figure 8.15 shows a typical tape cross section. The second process required is the gang bonding of the semiconductor die to the lead frame. This process is called inner lead bonding and utilizes either thermocompression or solder joining techniques. This operation is a critical part of the process and requires compatible metals on the lead frame and semiconductor die. The third process is the gang bonding of the devices to metallized ceramic substrates. This process is called outer lead bonding and consists of severing the chip and part of the lead frame from the carrier, forming the severed leads and thermocompression bonding of these leads to the substrate. The final assembled chip is shown in Figure 8.16.
L
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
lead frame excessive amplification and transmission of undesirable noise. lead frame the metallic portion of the device package that makes electrical connections from the die to other circuitry. lead lanthanum zirconium titanate (PLZT) a quadratic electro-optic material where the refractive index changes quadratically with applied electric field. Commonly available as a hot-pressed polycrystalline ceramic, although single-crystal film is being developed. leader an elongated region of ionized gas that extends from one electrode to another just before a high-voltage breakdown. leader-follower game rium. See Stackelberg equilibleaky feeder an antenna consisting of a cable that continuously radiates a signal from all points along the entire length of the cable. Such a cable is typically used as the radiating antenna in places such as tunnels and mines where the range of radio propagation is limited. Compare with distributed antenna. leaky modes See tunneling modes.
Packaging and Assembly of Microelectronic Devices and Systems
Published in Anwar Sohail, Raja M Yasin Anwar Akhtar, Raja Qazi Salahuddin, Ilyas Mohammad, Nanotechnology for Telecommunications, 2017
Device packaging or Level 1 packaging involves the assembly and interconnection of the microelectronic, optoelectronic, or microsystems device onto a lead frame arrangement or substrate. The lead frame is the framework that provides mechanical support to the die. The electrical connections between the die and the leads are established by means of a wire bond. The lead frame consists of a die paddle, to which the die is attached, and leads, which serve as the means for an external electrical connection to the outside world (Figure 14.13). Lead frames are constructed from a flat sheet of metal either by stamping or etching processes. The use of substrates is becoming more commonplace when compared with lead frames, as the industry migrates more and more toward leadless and area array packages.
Microstructure evolution and precipitation behaviour of the Cu-Ni-Si-Cr alloy based on twin-roll strip casting
Published in Philosophical Magazine, 2023
Guangming Cao, Ruixiang Li, Shuang Zhang, Hao Wang, Yuanxiang Zhang
The Cu-Ni-Si alloy has been widely used in lead frame materials and has a strong substitution effect on brass beryllium copper alloys because of its excellent comprehensive properties [1–3]. To further improve the properties of materials, high alloying is an effective process. However, high alloying materials are difficult to bereasonably processed because the defects such as severe segregation and coarse grain caused seriously effects on the properties of alloys [4,5]. Therefore, an appropriate process is needed to solve these problems.