MCC has been developing the use of flashlamp pulsed Nd:YAG laser technology to bond TAB leadframes to bumped IC die. With basic equipment, the process has been proven in a laboratory scale environment. As a result, MCC recently licensed a vendor to manufacture the equipment so that it can be used in prototype and later in production environments. This project was initiated to develop a benign alternative for thermocompression gang bonding, particularly for applications where IC bond pads would be located over active circuitry. In addition, because the laser beam's positions are computer controlled, the process has shown to be very desirable for bonding conventional devices with peripheral pads, especially in high product mix applications. Bond rates of 40 bonds/second have been demonstrated at MCC. The first production prototype will bond at 60–80 bonds/s and it is anticipated that, with further development, the full production equipment will bond at 200 bonds/s. The process that is most mature at the time of writing is for bonding tin plated copper leads to gold bumps. This system allows formation of reliable bonds because the formed bonds consist primarily of copper and gold. The bonds are at least as strong and reliable as with other methods of TAB bonding. Bonds with this metallurgical system have been subjected to severe environmental testing without failure. This paper will present results of laser inner lead bonding, the equipment used to develop it and the expectations of the future equipment as well as the future of the technology itself.
Since 1985, MCC has been developing the use of flashlamp pulsed Nd:YAG (YAG) laser technology to bond tape automated bonding (TAB) leads to I/O pads on integrated circuits (ICs). The I/O pads have 22 micron high gold bumps and the leads are copper plated, in the case described here, with electroless tin. As a result of the work presented here, a methodology has been developed that will result in a high throughput, reliable bonding process that overcomes the limitations of conventional thermocompression (T/C) and thermosonic (T/S) bonding technologies. In addition, because the position of the laser beam is software controlled, the process is very desirable for applications where a broad range of different IC form factors and sizes are to be bonded. Laser bonded devices have been exposed to degrading environments without failure, indicating the long term reliability of the process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.