Diamond-Tipped and Other New Thermodes for Device Bonding

Work is reported on the design and evaluation of new device-bonding thermodes with improved thermal properties. The present conventional titanium-carbide-tipped thermodes may have inadequate heat-transfer characteristics for certain new TAB and beamlead bonding applications. Two new thermodes were constructed. One of the new thermodes has a diamond bonding tip. A unique feature of this thermode is that the diamond tip contains a laser machined cavity to accommodate the device to be bonded. In the other new thermode the cavity is conventionally machined directly into the Inconel body. The two new thermodes and a conventional thermode were compared in terms of their ability to attain various interface temperatures as a function of thermode body and substrate temperatures. The latter two were varied over the ranges of 50°C-650°C and 25°C-200°C, respectively. It was found that the diamond-tipped thermode clearly exhibits the best heat-transfer characteristics. However, the solid Inconel thermode also shows considerable improvement over the conventional thermode.