Device for probe card power bus noise reduction

Abstract

Noise reduction for application of structural test patterns to a Device Under Test (DUT) is accomplished with a capacitor “booster” bypass network on the probe card in which the capacitors are charged to a much higher voltage V boost than the DUT power supply voltage VDD. Charging the capacitors to a voltage N×VDD allows the buster network to store N times the charge of a conventionally configured capacitance network, and effectively provides N times the capacitance of the original network in the same physical space.

1 . A voltage drop suppression device for maintaining constant voltage on a power bus of a probe card used for semiconductor wafer testing, the device comprising:
 a bypass capacitor mounted the probe card, wherein the bypass capacitor is charged to a voltage greater than a power supply voltage VTDD of a device under test; and   an active regulation circuit controlling the discharge of the bypass capacitor to supply current to the power bus for suppressing a voltage drop on the power bus generated by a current surge during testing of the device under test.   
   
   
       2 . The voltage drop suppression device recited in  claim 1 , wherein the active regulation circuit is self regulating, not requiring synchronization to an external test of any kind, nor any kind of calibration sequence prior to use. 
   
   
       3 . The noise voltage drop suppression device recited in  claim 1 , wherein the bypass capacitor is implemented as a bank of bypass capacitors. 
   
   
       4 . (canceled) 
   
   
       5 . (canceled) 
   
   
       6 . The voltage drop suppression device recited in  claim 1 , wherein the bypass capacitor is charged to a voltage at least 10 times the voltage of the power supply voltage VDD. 
   
   
       7 . The voltage drop suppression device recited in  claim 1 , wherein the bypass capacitor is charged to a voltage at least 2 times the voltage of the power supply voltage VDD. 
   
   
       8 . The voltage drop suppression device recited in  claim 1 , wherein said bypass capacitor is charged to a maximum capacity.