Method of Producing an Ohmic Contact to the Back Side of a Semiconductor Wafer
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
For producing an ohmic contact to the back side of a semiconductor test wafer 1, the latter is sucked onto a special chuck 3 by means of vacuum 2. The vacuum chuck has several pot-shaped electrodes 4 which are electrically insulated from each other and the bottom end of which is provided with a cylindrical protrusion 5 with a vertical bore 6. The electrodes are fixed in an electrically insulating material 9 by means of spacers 7 and screws 8. Each electrode has an electrical connector lug 10. For ensuring reliable electric contact to the back side of the wafer, current pulses are fed through two electrodes each. These pulses locally melt or sinter the back side of the wafer, thus ensuring reliable electric contact which is necessary for different measurements.