High Resolution Analytical Probe Station

Abstract

A method and system for probing with electrical test signals on an integrated circuit specimen using a high resolution microscope positioned for observing a surface of the specimen exposing electrically conductive terminals thereon. A housing is provided with a carrier therein for supporting the specimen in relation to the microscope and a probe assembly is positionable on the surface of the specimen for conveying and acquiring electrical test signals to and from the specimen. A drive system is provided for shifting at least one of the probe and the carrier to a predetermined test position. In one form the system has a heat shield for protecting one of the probe assembly and the carrier from heat energy generated upon operation of the drive system, and in another form, the system has an environmental control for maintaining a desired temperature within the housing so that accurate measurements may be taken from the specimen.

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       8 . A probe station for high resolution, low current probing of a DUT, the probe station comprising: 
 a vacuum housing having an interior space in which a DUT is disposed with the interior space under vacuum conditions during testing operations;    a high resolution microscope extending into the interior space for acquiring images of the DUT;    a probe assembly in the housing interior space for taking low current measurements from the DUT;    a carrier in the housing space for supporting the DUT during testing operations;    a drive system for shifting at least one of the probe assembly and the carrier to a predetermined test position; and    means for causing precision movements of the at least one of the probe assembly and the carrier via operation of the drive system in the vacuum housing despite generation of heat energy upon drive system operation.    
   
   
       9 . The probe station of  claim 8  wherein the means for causing precision movements comprises a heat insulating or heat shielding device connected to the drive system to allow for precision shifting of the at least one of the probe assembly and the carrier by the drive system in the vacuum housing.  
   
   
       10 . The probe station of  claim 8  wherein the drive system includes a motor and the means for causing precision movements comprises an output shaft assembly of the motor of a predetermined heat insulating material.  
   
   
       11 . The probe station of  claim 10  wherein the output shaft assembly includes a lead screw that is of the predetermined heat insulating material which comprises at least one of a ceramic material, sapphire material and ruby material having a low coefficient of thermal expansion.  
   
   
       12 . The probe station of  claim 8  wherein the drive system includes a motor and a motor output shaft assembly and the means for causing precision movements comprises a coupling made of a predetermined heat insulating material which insulates portions of the output shaft assembly from each other in order to minimize heat transfer from one portion to another portion.  
   
   
       13 . The probe station of  claim 8  wherein the drive system includes a motor and a drive shaft that is rotated upon operation of the motor for shifting the one of the probe and the carrier by the drive system in the vacuum housing; and 
 the means for causing precision movements comprises a shield disposed between the motor and the drive shaft to deflect heat or energy from the operating motor away from the drive shaft in the vacuum housing.    
   
   
       14 . The probe station of  claim 13  wherein the shield forms an annular ring about the motor and extends out from the motor at an angle sufficient to deflect radiated heat or energy from the operating motor away from the drive shaft in the vacuum housing.  
   
   
       15 . The probe station of  claim 8  further comprising an environmental control system associated with the housing and including a heat transfer fluid that substantially maintains a desired temperature within the vacuum housing so that accurate measurements may be taken from the DUT.  
   
   
       16 . The probe station of  claim 15  wherein the environmental control system further includes a conduit disposed within the vacuum housing for carrying the heat transfer fluid therein.  
   
   
       17 . The probe station of  claim 15  wherein the environmental control system conduit comprises a group of lines positioned about the at least one of the probe assembly, carrier and drive system, the lines carrying the heat transfer fluid for transferring heat to maintain a desired temperature within the vacuum housing.