Wafer burn-in and test employing detachable cartridge
A cartridge ( 10 ) includes a chuck plate ( 12 ) for receiving a wafer ( 74 ) and a probe plate ( 14 ) for establishing electrical contact with the wafer. In use, a mechanical connecting device ( 90 ) locks the chuck plate and the probe plate fixed relative to one another to maintain alignment of the wafer and the probe plate. Preferably, electrical contact with the wafer is established using a probe card ( 50 ) that is movably mounted to the probe plate by means of a plurality of leaf springs ( 52 .) The mechanical connecting device is preferably a kinematic coupling including a male connector ( 94 ) and first and second opposed jaws ( 122, 124 .) Each of the jaws is pivotable from a retracted position in which the male connector can be inserted between the jaws and an engaging position in which the jaws prevent withdrawal of the male connector from between the jaws. The male connector is movable between an extended and a retracted position, and is biased towards the retracted position. This provides a positive clamping force that pulls the chuck and probe plates together when the mechanical connecting device is engaged. To load a wafer into the cartridge, the wafer is placed on the chuck plate, the probe plate is aligned with the wafer, and the chuck plate and the probe plate are locked together. The cartridge can then be removed from the alignment device and placed in a burn-in or test chamber that does not itself require means for aligning the wafer or for providing a probe actuation force.
1. A cartridge for burn-in or test, comprising:
a chuck plate to receive a wafer, the wafer having a surface;
a probe plate;
a mechanical device to lock the chuck plate and the probe plate fixed relative to one another;
a probe card for establishing the electrical contact with the wafer, the probe card movably mounted to the probe plate; and
a mechanism that permits relative motion between the probe card and the probe plate normal to the surface of the wafer, allowing the probe card to move, relative to the probe plate, from a position not in contact with the surface of the wafer to a position in contact with the wafer, while preventing substantial rotation of the probe card and preventing substantial movement of the probe card along the directions parallel to the surface of the wafer.
2. The cartridge of claim 1 , including a flexible connection for electrical connection with the probe card.
3. The cartridge of claim 1 , including bendable printed circuit boards electrically coupled to the probe card.
4. The cartridge of claim 1 , wherein the mechanism that prevents the relative motion comprises at least one complaint member that mounts the probe card probe plate.
5. The cartridge of claim 4 wherein the at least one compliant member comprises at least two leaf springs.
6. The cartridge of claim 5 wherein each leaf spring has a non-linear profile.
7. The cartridge of claim 6 , wherein each leaf spring includes a curved central portion.
8. The cartridge of claim 7 , wherein each leaf spring includes a channel-shaped central portion extending across the width of the leaf spring.
9. The cartridge of claim 5 , wherein the leaf springs are spaced about the circumference of the probe card to provide a substantially maximum resistance to rotation of the probe card relative to the probe plate about an axis normal to a probed wafer.
10. The cartridge of claim 5 , wherein the leaf springs are spaced about the circumference of the probe card to provide a substantially maximum resistance to rotation of the probe card relative to the probe plate about an axis normal to the wafer.
11. The cartridge of claim 10 , including a piston slidably located in a recess formed in the probe plate behind the probe card.
12. The cartridge of claim 4 , including a piston slidably located in a recess formed in the probe plate behind the probe card.
13. The cartridge of claim 1 , wherein the probe card is rectangular in shape and there is one leaf spring located near each of the four corners of the probe card.
14. The cartridge of claim 1 , wherein the probe card and the probe plate have mismatch of thermal coefficients of expansion.
15. The cartridge of claim 14 , wherein the probe card comprises a material thermally matched the semiconductor material comprised by the wafer.
16. The cartridge of claim 14 , wherein the probe card is mounted to the probe plate by a spring having a compliance that predictably compensates for any changes in dimension resulting from mismatch of the thermal coefficients of expansion.
17. The cartridge of claim 1 , wherein the probe card comprises a material thermally matched to the semiconductor material comprised by the wafer.
18. The cartridge of claim 1 , wherein the probe card and other portions of the cartridge have thermal mismatch.
19. The cartridge of claim 18 , wherein the other portions of the cartridge comprise printed circuit boards.
20. The cartridge of claim 1 , including means for minimizing thermal mismatch between the probe card and other portions of the cartridge.
21. The cartridge of claim 1 , wherein the probe card is mounted at its center.
22. The cartridge of claim 21 , wherein the mechanism that prevents the relative motion comprises a guide plug to which the probe card is mounted.
23. The cartridge of claim 1 , including a piston slidably located in a recess formed in the probe plate behind the probe card.
24. The cartridge of claim 1 , including a printed circuit board mounted to the probe plate and electrically coupled to probe card.
25. The cartridge of claim 24 , including electrical connectors mounted to the exterior of the probe plate, the electrical connectors being electrically coupled to the printed circuit board.
26. The cartridge of claim 25 , including a flexible connection for electrical connection between the probe card and the circuit board.