PATENT COVER GRAPHIC


United States Patent 3,533,155
October 13, 1970

Bonding With A Compliant Medium
Alexander Coucoulas

Filed July 6, 1967
Image of US PATENT 3,533,155

Abstract of the Disclosure

The bonding of two workpieces by ultrasonic or thermocompression techniques requires the use of a rigid bonding tip or ram to transmit the bonding energy, whether it be vibratory, mechanical and/or thermal. In time, such a rigid medium is subject to wear, to misalignment and to pickup of material from the workpieces, the latter causing the upper workpiece to stick to the tip. Further, such a rigid medium cannot be used reliably, to make a number of bonds simultaneously, because minor size differences in the workpieces can prevent a good couple for energy transmission from being established to every workpiece. It has been discovered that a compliant or deformable medium can be employed to hod the workpieces during bonding. By deforming around the workpieces, the compliant medium eliminates the problem of size differences, as well as wear, misalignment and the like, and a good bond is achieved in each instance. In one aspect, the bonding energy is transmitted through the compliant medium to make the bond. In a second aspect, the bonding energy is transmitted through the support for the workpieces. The quality of individual bonds is imporved because, for a given set of bonding conditions, there is less deformation of the workpieces than with conventional techniques. The invention is particularly applicable to the bonding of beam-lead transistors and integrated circuits to substrates, to bonding a plurality of leads to integrated circuit and thin film devices, and to bonding brittle single crystal chips to substrates.
Figure descriptions: cover graphic

  • Figures 1A and 1B are side and end elevations, respectively, showing all parts in place for bonding a lead to a substrate by thermocompression bonding in accordance with the invention.
  • Figures 2A and 2B are similar to Figures 1A and 1B, showing all parts during thermocompression bonding in accordance with the invention.
  • Figures 3A and 3B are similar to Figures 1 and 2, showing all parts after thermocompression bonding is complete.
  • Figure 12 is a perspective view of a lead frame for a beam lead device or devices for used in thermocompression bonding in accordance with the invention.

 Citations [54]:
  
3,110,961 11/1963 Melill et al
National Museum of American History
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