Stock material or miscellaneous articles – All metal or with adjacent metals – Composite; i.e. – plural – adjacent – spatially distinct metal...
Reexamination Certificate
1997-10-02
2001-06-12
Jones, Deborah (Department: 1775)
Stock material or miscellaneous articles
All metal or with adjacent metals
Composite; i.e., plural, adjacent, spatially distinct metal...
C428S615000, C428S617000, C428S620000, C428S212000, C428S332000, C267S156000, C267S167000
Reexamination Certificate
active
06245444
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to micromachined systems and elements generally and, more particularly, but not by way of limitation, to microsensors, microactuators, microprobes, and probe cards and, more particularly, but not by way of limitation, to a novel micromachined coiled element and method of fabrication thereof.
DESCRIPTION OF THE RELATED ART
Various micromachined or microelectromechanical devices, such as sensors and actuators, on a microscopic scale have been developed.
For example, U.S. Pat. No. 5,434,513 issued to Fujii et al. discloses a semiconductor wafer testing apparatus capable of allowing numerous circuit elements of a semiconductor wafer to be tested at once. A plurality of pogo pins which have moveable connection pins inserted therein, are urged downward and are moveable in an axial direction, wherein the tips of the respective connection pins contact the pickup electrodes or control electrodes formed on the semiconductor wafer, with pressure, to provide electrical connections.
U.S. Pat. No. 5,172,050 issued to Swapp discloses a probe fixture for testing an integrated circuit, the probe fixture including a semiconductor substrate, a plurality of cavities etched into the substrate, a plurality of flexible beams formed from the substrate, wherein each beam extends over a portion of each of the cavities, a plurality of conductive probe tips, wherein each probe tip is formed on one of the beams, and a conductive interconnect formed on the substrate for coupling each probe tip to an external circuit tester. The electrode pads are forced into contact with the probe tips when the semiconductor probe card and integrated circuit are pressed firmly together.
U.S. Pat. No. 4,520,314 issued to Asch et al. discloses a test probe head for contacting and testing a plurality of exposed closely spaced electrically conductive members of very small dimensions, wherein the probe comprises a monolithic monocrystalline silicon comb-shaped structure having a spine portion and a plurality of elongated teeth which provide a plurality of miniature resilient cantilever beams.
U.S. Pat. No. 5,415,555 issued to Sobhani discloses an electrical interconnection apparatus which utilizes raised connecting means. A pair of electrical circuits, which may be both flexible, or one flexible and one rigid, are interconnected by projections, such as bumps or rings.
U.S. Pat. No. 5,012,187 issued to Littlebury teaches a method of testing integrated circuits using a tester which is capable of testing a plurality of memories in parallel. A membrane test head having a plurality of probe bumps is coupled to the tester.
U.S. Pat. No. 5,510,721 issued to Walles et al. discloses a test socket for testing an integrated circuit, wherein a substrate has a plurality of trenches that are traversed by a plurality of resilient conductive straps which extend across the trenches. The straps are deformed in a predetermined manner into the trenches while the straps are urged against the contacts.
Patent No. EP 687 907 issued to Hamasaki discloses a microeddy current sensor having a coil formed on a silicon substrate by a micromachining technique wherein the coil is formed by electrode deposition of a metal. The coil has a multilayered structure in the vertical direction and/or a core formed proximate the central position of the coil. A resist layer is formed on a silicon substrate through an insulating film by micromachining, and a spiral groove is two-dimensionally formed in the resist layer by patterning, whereafter a metal such as copper is buried in the groove by electrodeposition, thereby forming a coil, resulting in a microeddy current sensor which can detect a small change in magnetic field.
U.S. Pat. No. 4,740,410 issued to Muller et al. discloses a method, and the product resulting therefrom, for making a microminiature structure with two or more members which are relatively moveable to each other, such as a spring-restrained pin joint. A spiral spring extends through two and half revolutions and is made of two micrometer-wide second-layer polysilicon. The central end of the spring is connected to a hub, and the outer end is connected to a moveable arm. The horizontal spring structure is used in ratchet closures and brush-contact detents.
Patent No. WO 96/24145 issued to Ho discloses a micromachined micromagnetic actuator having a flap capable of large deflections using a magnetic actuating force. The flap is coupled by one or more beams to a substrate, and is cantilevered over the substrate. A magnetic layer or magnetic coil is disposed on the flap, wherein the flap is selectively rotated out of the plane of the substrate. The flap comprises different layers, and the intrinsic stresses of the different layers contribute to a bending moment which causes the flap to be curved, rather than flat, at rest. Thermal mismatch of different materials in the composite layers causes the flap to bend down. The motion of the flap is a result of both thermal and magnetic effects. The patent also discloses a method of fabricating the microelectromagnetic actuator, wherein the method comprises providing a substantially completed actuator on a sacrificial layer disposed on an underlying substrate, removing the sacrificial layer by etching away through at least one opening defined through the actuator to expose the underlying sacrificial layer, and drying the actuator while simultaneously actuating the actuator to maintain the released portions of the actuator out of contact with the underlying substrate until the drying is complete.
Many of the techniques used in silicon chip processing have been used to produce these devices. The techniques include photolithography, x-ray and beam lithography, layer deposition and etching techniques.
Wafer probe cards may incorporate an array of elements for device characterization. Various elements such as cantilevers and probes of various shapes, structures, compositions, and membrane probe card structures have been developed for testing of semiconductor chips.
U.S. Pat. No. 5,475,318 issued to Marcus et al. discloses a microprobe comprising a bimorph actuated microcantilever having a probe tip which projects from the microcantilever. Upon heating of the microcantilever, the probe tip comes into contact with a material to be investigated.
Wafer-stage testing of semiconductor chips is pervasive throughout the industry. As chips get larger and more complex, such testing becomes increasingly difficult to execute with existing probe/test technology. As chips get more complex, the various components become smaller, their numbers increase, and the number of I-O pads on a device increases. Testing becomes even more difficult where contact surfaces are non-planar, such as encountered with solder bumps, curved “smart skin” surfaces, or in multi-chip assemblies.
Known membrane probes consist of an arrangement of probe contact pads on a membrane which are made to contact the device pads by applying a small pressure, forcing the two together. Although membrane probe card technology might be used for probing and testing the next generation of chips and packages, various problems inherent with the membrane probe card exist, as related, for example, to the increasing size of the membrane required for larger chips (in order to reduce the effect of bowing), the inability of the membrane probe card to offer compliant contact with surfaces of varying height as with the components of a Multi-Chip-Module (MCM), and the overall difficulty of using a membrane technology compared with a technology based on a rigid surface, such as a surface based upon silicon.
Therefore, the need exists, and continues to grow, for contacting circuits on wafers having varying heights or nonuniform surfaces for purposes of testing and/or connection with, or interconnection between, circuit elements during operation.
Accordingly, it is an object of the present invention to provide a microprobe which has a built-in compliancy for contacting adjacent surfaces of varying heights. Such a feature is absen
Marcus Robert B.
Zhang Yanwei
Jones Deborah
Klauber & Jackson
New Jersey Institute of Technology
Savage Jason
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