Formfactor, Inc.

Bioscale, Inc.

Stuart W Wenzel

Benjamin N Eldridge

Gaetan L Mathieu

Charles A Miller

Scott E Lindsey

Eric E Fitch

David M Royster

Igor Y Khandros

An electronic component is disclosed, having a plurality of microelectronic spring contacts mounted to a planar face of the component. Each of the microelectronic spring contacts has a contoured beam, which may be formed of an integral layer of resilient material deposited over a contoured sacrificial substrate, and comprises a base mounted to the planar face of the component, a beam connected to the base at a first end of the beam, and a tip positioned at a free end of the beam opposite to the base. The beam has an unsupported span between its free end and its base. The microelectronic spring contacts are advantageously formed by depositing a resilient material over a molded, sacrificial substrate. The spring contacts may be provided with various innovative contoured shapes. In various embodiments of the invention, the electronic component comprises a semiconductor die, a semiconductor wafer, a LGA socket, an interposer, or a test head assembly.

Electronic components with plurality of contoured microelectronic spring contacts

Improved lithographic type microelectronic spring structures and methods are disclosed, for providing improved tip height over a substrate, an improved elastic range, increased strength and reliability, and increased spring rates. The improved structures are suitable for being formed from a single integrated layer (or series of layers) deposited over a molded sacrificial substrate, thus avoiding multiple stepped lithographic layers and reducing manufacturing costs. In particular, lithographic structures that are contoured in the z-direction are disclosed, for achieving the foregoing improvements. For example, structures having a U-shaped cross-section, a V-shaped cross-section, and/or one or more ribs running along a length of the spring are disclosed. The present invention additionally provides a lithographic type spring contact that is corrugated to increase its effective length and elastic range and to reduce its footprint over a substrate, and springs which are contoured in plan view. The present invention further provides combination (both series and parallel) electrical contacts tips for lithographic type microelectronic spring structures. The microelectronic spring structures according to the present invention are particularly useful for making very fine pitch arrays of electrical connectors for use with integrated circuits and other substrate-mounted electronic devices, because their performance characteristics are enhanced, while at the same time, they may be manufactured at greatly reduced costs compared to other lithographic type microelectronic spring structures.

Lithographic type microelectronic spring structures with improved contours

An interconnection element that includes a first element material adapted to be coupled to a substrate and a second element material comprising a material having a transformable property such that upon transformation, a shape of the interconnection is modified. An example is a material that has a transformable property such that a volume of the first and/or second element material may undergo a thermal transformation from one volume to a different volume (such as a smaller volume).

Shaped spring

A method and system for determining properties of a fluid involves interacting the fluid with a standing wave in a first state to establish the standing wave in a second state, analyzing an electric signal associated with the standing wave to determine a characteristic associated with the second state, and determining the property of the fluid by comparing the characteristic with a function that associates a plurality of properties with a corresponding plurality of characteristics. The characteristic can include a maximum phase slope, a phase slope associated with a resonant frequency, a maximum magnitude associated with the resonant frequency, the value of the resonant frequency, or any combination thereof.

Methods and apparatus for determining properties of a fluid

A test head assembly can include a probe card, which can include first contact areas. The test head assembly can also include a contactor, which can include second contact areas. An interposer can include first spring contact structures and second spring contact structures. The first spring contact structures can contact one of the first contact areas, and the second spring contact structures can contact one of the second contact areas. Ones of the first spring contact structures can be electrically connected through the interposer to ones of the second spring contact structures. One of the first spring contact structures can include a pair of contacts, both of which can extend from a first surface of the interposer to contact one of the first contact areas. Alternatively or additionally, one of the second spring contact structures can include a pair of contacts, both of which can extend form a second surface of the interposer to contact one of the second contact areas.

Test head assembly having paired contact structures

A microelectronic spring contact for making electrical contact between a device and a mating substrate and method of making the same are disclosed. The spring contact has a compliant pad adhered to a substrate of the device and spaced apart from a terminal of the device. The compliant pad has a base adhered to the substrate, and side surfaces extending away from the substrate and tapering to a smaller end area distal from the substrate. A trace extends from the terminal of the device in a coil pattern over the compliant pad to its end area, forming a helix. At least a portion of the compliant pad end area is covered by the trace, and a portion of the trace that is over the compliant pad is supported by the compliant pad. In an alternative embodiment, the pad is removed to leave a freestanding helical contact.

Helical microelectronic contact and method for fabricating same

A method of fabricating and using an interconnection element that includes a first element material adapted to be coupled to a substrate and a second element material comprising a material having a transformable property such that upon transformation, a shape of the interconnection is deformed. An example is a material that has a transformable property such that a volume of the first and/or second element material may undergo a thermal transformation from one volume to a different volume (such as a smaller volume) resulting in the deformation of the interconnection element.

Methods of fabricating and using shaped springs

A microelectronic spring contact for making electrical contact between a device and a mating substrate and method of making the same are disclosed. The spring contact has a compliant pad adhered to a substrate of the device and spaced apart from a terminal of the device. The compliant pad has a base adhered to the substrate, and side surfaces extending away from the substrate and tapering to a smaller end area distal from the substrate. A trace extends from the terminal of the device over the compliant pad to its end area. At least a portion of the compliant pad end area is covered by the trace, and a portion of the trace that is over the compliant pad is supported by the compliant pad. A horizontal microelectronic spring contact and method of making the same are also disclosed. The horizontal spring contact has a rigid trace attached at a first end to a terminal of a substrate. The trace is free from attachment at its second end, and extends from the terminal in a direction substantially parallel to a surface of the substrate to the second end. At least a distal portion of the trace extending to the second end is spaced apart from the surface of the substrate. The spaced-apart distal portion is flexible in a plane parallel to the substrate.

Layered microelectronic contact and method for fabricating same

A method for fabricating microelectronic spring structures is disclosed. In an initial step of the method, a layer of sacrificial material is formed over a substrate. Then, a contoured surface is developed in the sacrificial material, such as by molding the sacrificial material using a mold or stamp. The contoured surface provides a mold for at least one spring form, and preferably for an array of spring forms. If necessary, the sacrificial layer is then cured or hardened. A layer of spring material is deposited over the contoured surface of the sacrificial material, in a pattern to define at least one spring form, and preferably an array of spring forms. The sacrificial material is then at least partially removed from beneath the spring form to reveal at least one free-standing spring structure. A separate conducting tip is optionally attached to each resulting spring structure, and each structure is optionally plated or covered with an additional layer or layers of material, as desired. An alternative method for making a resilient contact structure using the properties of a fluid meniscus is additionally disclosed. In an initial step of the alternative method, a layer of material is provided over a substrate. Then, a recess is developed in the material, and fluid is provided in the recess to form a meniscus. The fluid is cured or hardened to stabilize the contoured shape of the meniscus. The stabilized meniscus is then used to define a spring form in the same manner as the molded surface in the sacrificial material.

Method for forming microelectronic spring structures on a substrate

Test head assembly for electronic components with plurality of contoured microelectronic spring contacts

A forming tool with one or more embossing tooth, and preferably, a plurality of such embossing teeth, arranged on a substantially planar substrate, is disclosed. Each embossing tooth is configured for forming a sacrificial layer to provide a contoured surface for forming a microelectronic spring structure. Each embossing tooth has a protruding area corresponding to a base of a microelectronic spring, and a sloped portion corresponding to a beam contour of a microelectronic spring. Numerous methods for making a forming tool are also disclosed. The methods include a material removal method, a molding method, a repetitive-stamping method, tang-bending methods, and segment-assembly methods.

Growing community of inventors

San Francisco, CA, United States of America

Stuart W Wenzel