Method and system for compensating thermally induced motion of probe cards
View Patent ↗A method and system for compensating for thermally induced motion of probe cards used in testing die on a wafer are disclosed. A probe card incorporating temperature control devices to maintain a uniform temperature throughout the thickness of the probe card is disclosed. A probe card incorporating bi-material stiffening elements which respond to changes in temperature in such a way as to counteract thermally induced motion of the probe card is disclosed including rolling elements, slots and lubrication. Various means for allowing radial expansion of a probe card to prevent thermally induced movement of the probe card is disclosed. A method for detecting thermally induced movement of the probe card and moving the wafer to compensate is also disclosed.
1. An apparatus comprising:
a probe card for testing a die on a wafer;
a multi-layer element having a first layer and a second layer, said first layer and said second layer having different rates of expansion per unit of energy, said multi-layer element being attached to said probe card, wherein exposing said multi-layer element to energy causes said multi-layer element to selectively impart deflective forces to a portion of said probe card.
2. The apparatus of claim 1 wherein said multi-layer element includes two layers of different metals/alloys having a different coefficient of thermal expansion than the other.
3. The apparatus of claim 1 wherein said multi-layer element is located generally along a perimeter of said probe card.
4. The apparatus of claim 3 wherein said multi-layer element includes two layers of different metals/alloys having a different coefficient of thermal expansion than the other.
5. The apparatus of claim 3 and further comprising a stiffening element and means for facilitating radial expansion/contraction of said probe card with respect to said stiffening element.
6. The apparatus of claim 1 and further comprising a stiffening element and means for facilitating radial expansion/contraction of said probe card with respect to said stiffening element.
7. An apparatus comprising:
a probe card, wherein said probe card is part of an apparatus with a plurality of probes disposed to contact an electronic device to be tested, and wherein said probe card comprises a device side that faces said electronic device to be tested and a second side opposite said device side;
an energy transmissive element disposed to transmit energy to said probe card to counteract thermally induced bowing of said probe card, wherein said energy transmissive element is disposed to affect a temperature on said device side of said probe card; and
means for facilitating radial expansion/contraction of said probe card relative to a stiffening element.
8. The apparatus of claim 7 further comprising a multi-layer element comprising a first layer and a second layer, said first layer and said second layer having different thermal coefficients of expansion, said multi-layer element being disposed to impart deflective forces to at least a portion of said probe card when exposed to energy.
9. An apparatus comprising:
a probe card, wherein said probe card is part of an apparatus with a plurality of probes disposed to contact an electronic device to be tested, and wherein said probe card comprises a device side that faces said electronic device to be tested and a second side opposite said device side;
an energy transmissive element disposed to transmit energy to said probe card to counteract thermally induced bowing of said probe card, wherein said energy transmissive element is disposed to affect a temperature on said device side of said probe card; and
a multi-layer element comprising a first layer and a second layer, said first layer and said second layer having different thermal coefficients of expansion, said multi-layer element being disposed to impart deflective forces to at least a portion of said probe card when exposed to energy.