Testing head with improved frequency property

Abstract

A testing head comprises a plurality of contact probes, and a guide having a plurality of guide holes for housing the contact probes and including a conductive portion. Each contact probe includes a first end region and a second end region, and a body which extends between the first and second end regions. Suitably, the conductive portion includes a group of the guide holes and electrically connects contact probes of a first group of the contact probes. The contact probes of the first group slide in the guide holes in the conductive portion and are adapted to carry a same signal, and each contact probe of a second group of the plurality of contact probes is surrounded by an insulating coating layer that extends along the body of each contact probe of the second group, thereby insulating the contact probes of the second group from the conductive portion.

1 . A testing head comprising:
 a plurality of vertical contact probes made of a conductive material, each contact probe comprising:
 a first end region and a second end region; and 
 a body which extends between the first end region and the second end region; and 
   a guide including a plurality of housing guide holes to house the plurality of vertical contact probes so that each vertical contact probe slides in a housing guide hole   wherein the plurality of vertical contact probes comprises a first group of vertical contact probes housed and a second group of vertical contact probes, and plurality of housing guide holes comprises:   a first group of housing guide holes, each housing guide hole of the first group housing a vertical contact probe of the first group of vertical contact probes, the vertical contact probes of the first group sliding in respective ones of the plurality of first housing guide holes; and   a second group of housing guide holes, each housing guide hole of the second group housing a vertical contact probe of the second group of vertical contact probes the vertical contact probes of the second group sliding in respective ones of the plurality of second housing guide holes;   wherein the guide comprises at least one conductive portion realized on one face of the guide and extending on the guide so as to surround the housing guide holes of the first group and of the second group, the at least one conductive portion extending also along the rim of the housing guide holes,   wherein each vertical contact probe of the second group of vertical contact probes is surrounded by a coating layer made of an insulating material, at least at a portion of the body of the each vertical contact probe of the second group that is in contact with the rim of the respective housing guide hole of the second group during the working of the testing head,   wherein the at least one conductive portion realized on one face of the guide electrically connecting contact probes of the first group being adapted to carry a same signal, and   wherein the insulating coating layer realized on the probe body of each contact probe of the second group of contact probes electrically insulating contact probes of the second group from the at least one conductive portion.   
     
     
         2 . The testing head of  claim 1 , wherein the at least one conductive portion is configured to be connected to a common signal reference selected from a ground reference, a power reference, or an operating signal reference. 
     
     
         3 . The testing head of  claim 1 , wherein the at least one conductive portion comprises an orthogonal portion which extends at least partially within the housing guide holes of the first group, the orthogonal portion being electrically connected to the at least one conductive portion at respective rims at each of the housing guide holes of the first group. 
     
     
         4 . The testing head of  claim 1 , wherein the at least one conductive portion entirely covers the face of the guide. 
     
     
         5 . The testing head of  claim 1 , wherein the face is an exterior face of the guide that faces away from a device under test. 
     
     
         6 . The testing head of  claim 1 , wherein the face is an interior face of the guide that faces towards a device under test. 
     
     
         7 . The testing head of  claim 1 , wherein the guide is fully conductive. 
     
     
         8 . The testing head of  claim 1 , wherein the guide is chosen between an upper guide, a lower guide or an additional guide of the testing head. 
     
     
         9 . The testing head of  claim 1 , wherein the coating layer is a thin film having a thickness of less than 2 μm. 
     
     
         10 . The testing head of  claim 1 , wherein the coating layer is made by an insulating material selected from a polymeric or an organic insulating material. 
     
     
         11 . The testing head of  claim 1 , wherein the coating layer is made by an insulating material having a high hardness and being selected from a nitride, aluminium oxide, alumina, diamond-like carbon. 
     
     
         12 . The testing head of  claim 1 , wherein the coating layer extends along the whole probe body of the contact probes of the second group, except for the end regions thereof. 
     
     
         13 . The testing head of  claim 1 , wherein the conductive portion is made of a metallic material selected from copper, gold, silver, palladium, rhodium and their alloys. 
     
     
         14 . The testing head of  claim 1 , wherein the at least one guide is in proximity to a device under test (DUT) and comprises circuital components electrically connected to the at least one conductive portion. 
     
     
         15 . The testing head of  claim 14 , wherein the circuital components are filtering elements. 
     
     
         16 . A testing head comprising:
 a plurality of vertical contact probes made of a conductive material, each contact probe comprising:
 a first end region and a second end region; and 
 a body which extends between the first end region and the second end region; and 
   a guide including a plurality of housing guide holes to house the plurality of vertical contact probes so that each vertical contact probe slides in a housing guide hole   wherein the plurality of vertical contact probes comprises a first group of vertical contact probes housed and a second group of vertical contact probes, and plurality of housing guide holes comprises:   a first group of housing guide holes, each housing guide hole of the first group housing a vertical contact probe of the first group of vertical contact probes, the vertical contact probes of the first group sliding in respective ones of the plurality of first housing guide holes; and   a second group of housing guide holes, each housing guide hole of the second group housing a vertical contact probe of the second group of vertical contact probes the vertical contact probes of the second group sliding in respective ones of the plurality of second housing guide holes;   wherein the guide comprises at least one conductive portion realized on one face of the guide and extending on the guide so as to surround the housing guide holes of the first group and of the second group, the at least one conductive portion extending also along the rim of the housing guide holes,   wherein each vertical contact probe of the second group of vertical contact probes is surrounded by a coating layer made of an insulating material, extending along the whole probe body of the contact probes of the second group, except for the end regions thereof,   wherein the at least one conductive portion realized on one face of the guide electrically connecting contact probes of the first group being adapted to carry a same signal, and   wherein the insulating coating layer realized on the probe body of each contact probe of the second group of contact probes electrically insulating contact probes of the second group from the at least one conductive portion.   
     
     
         17 . The testing head of  claim 16 , wherein the at least one conductive portion is configured to be connected to a common signal reference selected from a ground reference, a power reference, or an operating signal reference. 
     
     
         18 . The testing head of  claim 16 , wherein the at least one conductive portion is chosen in the group consisting of: a conductive portion which comprises an orthogonal portion which extends at least partially within the housing guide holes of the first group, the orthogonal portion being electrically connected to the at least one conductive portion at respective rims at each of the housing guide holes of the first group, a conductive portion entirely which covers the face of the guide, a conductive portion realized on an exterior face of the guide that faces away from a device under test; a conductive portion realized on an an interior face of the guide that faces towards a device under test; and a conductive portion made of a metallic material selected from copper, gold, silver, palladium, rhodium and their alloys. 
     
     
         19 . The testing head of  claim 1 , wherein the coating layer is chosen in the group consisting of: a thin film having a thickness of less than 2 μm, a coating layer made by an insulating material selected from a polymeric or an organic insulating material, a coating layer is made by an insulating material having a high hardness and being selected from a nitride, aluminium oxide, alumina, diamond-like carbon. 
     
     
         20 . The testing head of  claim 1 , wherein the at least one guide is in proximity to a device under test (DUT) and comprises circuital components electrically connected to the at least one conductive portion.