MEMS PROBE CARD WITH ELASTIC MULTI-LAYER STRUCTURE
An MEMS probe card with elastic multi-layer structure mainly includes a substrate and a plurality of MEMS probe assemblies. The MEMS probe assemblies are disposed on a plurality of testing pads of the substrate, and each of the MEMS probe assemblies includes a plurality of first layer bridge elements, a second layer bridge element and a probe tip. The first and the second layer bridge elements each forms a π-shaped cross-section and has two piers and a beam. The piers of the second layer bridge elements are respectively disposed on the beams of the first layer elements, and the probe tips are disposed on the beams of the second layer bridge elements. According to the stacks formed by the second layer bridge elements disposing on the first layer bridge elements, the probe tips may have more elastic buffer and a better resistance to the compressive strain when probing the bumps or bonding pads on wafers.
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This application claims the priority benefit of Taiwan Patent Application Serial Number 094147737, filed on Dec. 30, 2005, the full disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention generally relates to an MEMS probe card, and more particularly to an MEMS probe card with multi-layer structure.
2. Description of the Related Art
Semiconductor devices have to be tested before packaging. A wafer is put in a testing machine with vertical probe tips, then utilizing the probe tips of a probe card to probe a plurality of bumps of input and output signal pads on the wafer. However, because the bumps disposed on the wafer have manufacturing variations, the heights of the bumps are different with each other especially those bumps need to be reflowed to ball bumps will have larger variations in height. To ensure the probe tips to electrically contact the bumps effectively, the probe tips may be designed to have elasticity so as to improve the electrical coupling between the probe tips and the bumps.
It is an object of the present invention to provide an MEMS probe card with elastic multi-layer structure. A substrate is disposed with a plurality of MEMS probe assemblies each having a plurality of first layer bridge elements, at least one second layer bridge element and a probe tip. The first layer bridge elements have a π-shaped cross-section and have two first piers and a first beam.
The second layer bridge element has a π-shaped cross-section and two of its piers are respectively disposed on the first beams of the first layer bridge elements. The probe tip is disposed on the second beam of the second layer bridge element. According to the stacking of the second layer bridge element on the first layer bridge elements, the probe tip may have more elastic buffer and a better resistance to compressive strain, and the counts of the MEMS probe assemblies may be increased.
It is an object of the present invention to provide an MEMS probe card with elastic multi-layer structure. The first and the second layer bridge elements are fabricated by electroplating with nickel, gold, copper, tungsten, titanium or their alloy, and the second layer bridge element is stacking on the first layer bridge elements and having an H-shaped vertical view with the first layer bridge elements such that the MEMS probe assemblies may have larger elasticity so as to probe the non-coplanar bumps or bonding pads on wafers.
According to the present invention, an MEMS probe card with elastic multi-layer structure mainly includes a substrate and a plurality of MEMS probe assemblies. The substrate has a plurality of testing pads, and the MEMS probe assemblies are disposed on the testing pads. Each of the MEMS probe assemblies includes a plurality of first layer bridge elements, at least one second layer bridge element and a probe tip, wherein each of the first layer bridge elements forms a π-shaped cross-section and has two first piers and a first beam, the second layer bridge element forms a π-shaped cross-section and has two second piers and a second beam, the second piers of the second layer bridge element are respectively disposed on the first beams of the first layer bridge elements, and the probe tip is disposed on the second beam of the second layer bridge element.
Other objects, advantages, and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Referring to
Referring to
Although the invention has been explained in relation to its preferred embodiment, it is not used to limit the invention. It is to be understood that many other possible modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the invention as hereinafter claimed.
Claims
1. An MEMS probe card with elastic multi-layer structure, comprising:
- a substrate having a plurality of testing pads; and
- a plurality of MEMS probe assemblies disposed on the testing pads, each of the MEMS probe assemblies comprising: a plurality of first layer bridge elements each having two first piers and a first beam; at least one second layer bridge element having two second piers and a second beam, the second piers being disposed respectively on the first beams of the first layer bridge elements; and a probe tip being disposed on the second beam of the second layer bridge element.
2. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, further comprising a printed circuit board.
3. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the material of the first and the second layer bridge elements is selected from the group of nickel, gold, copper, tungsten, titanium and their alloy.
4. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the first and the second layer bridge elements are fabricated by electroplating.
5. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the probe tips are fabricated by electroplating.
6. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the second layer bridge elements are stacking on the first layer bridge elements and having an H-shaped vertical view with the first layer bridge elements.
7. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the MEMS probe assemblies are arranged in matrix.
8. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the first layer bridge elements are arranged in parallel.
9. The MEMS probe card with elastic multi-layer structure as claimed in claim 1, wherein the first and the second layer bridge elements both form a π-shaped cross-section.
10. An MEMS probe card with elastic multi-layer structure, comprising:
- a substrate having a plurality of testing pads; and
- a plurality of MEMS probe assemblies disposed on the testing pads, each of the MEMS probe assemblies comprising: a plurality of first layer bridge elements each having two first piers and a first beam; a plurality of second bridge elements each having two second piers and a second beam, the second piers of the second layer bridge elements respectively disposed on the first beams of the first layer bridge elements; a third layer bridge element having two third piers and a third beam, the third piers of the third layer bridge element respectively disposed on the second beams of the second layer bridge elements; and a probe tip disposed on the third beam of the third layer bridge element.
11. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, further comprising a printed circuit board.
12. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the material of the first layer bridge elements, the second layer bridge elements and the third layer bridge elements is selected from the group of nickel, gold, copper, tungsten, titanium and their alloy.
13. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the first layer bridge elements, the second layer bridge elements and the third layer bridge elements are fabricated by electroplating.
14. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the probe tips are fabricated by electroplating.
15. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the second layer bridge elements are stacking on the first layer bridge elements and having a ∥-shaped vertical view with the first layer bridge elements, the third layer bridge elements are stacking on the second layer bridge elements and having an H-shaped vertical view with the second layer bridge elements.
16. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the MEMS probe assemblies are arranged in matrix.
17. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the first layer bridge elements are arranged in parallel, the second layer bridge elements are arranged in parallel.
18. The MEMS probe card with elastic multi-layer structure as claimed in claim 10, wherein the first layer bridge elements, the second layer bridge elements and the third layer bridge elements all form a π-shaped cross-section.
Type: Application
Filed: Nov 10, 2006
Publication Date: Jul 5, 2007
Applicant: ADVANCED SEMICONDUCTOR ENGINEERING INC. (KAOHSIUNG)
Inventor: Yu-Cheng Tsao (Kaohsiung City)
Application Number: 11/558,792
International Classification: G01R 31/02 (20060101);