Formfactor, Inc.

Other

Benjamin N Eldridge, Jr

Gaetan L Mathieu

Igor Y Khandros

Gary W Grube

David V Pedersen

Michael A Stadt

Richard Stephen Roy

Masanori Watanabe

Thomas H Dozier, Ii

A Nicholas Sporck

William D Smith

Poya Lotfizadeh

Chih-Chiang Tseng

Scott Kuhnert

Gayle J Herman

Junjye J Yeh

Jimmy Kuo-Wei Chen

Jeffrey Coussens

Igor K Khandros

In a probe card assembly, a series of probe elements can be arrayed on a silicon space transformer. The silicon space transformer can be fabricated with an array of primary contacts in a very tight pitch, comparable to the pitch of a semiconductor device. One preferred primary contact is a resilient spring contact. Conductive elements in the space transformer are routed to second contacts at a more relaxed pitch. In one preferred embodiment, the second contacts are suitable for directly attaching a ribbon cable, which in turn can be connected to provide selective connection to each primary contact. The silicon space transformer is mounted in a fixture that provides for resilient connection to a wafer or device to be tested. This fixture can be adjusted to planarize the primary contacts with the plane of a support probe card board.

Probe card assembly

The present invention provides an ancillary electrical component in very close proximity to a semiconductor device, preferably mounted directly to the semiconductor device. In one preferred embodiment, the ancillary electrical component is a capacitor. In a preferred embodiment, a terminal is provided on the semiconductor device such that the capacitor can be electrically connected directly to the terminals, as by soldering or with conductive epoxy. Connecting the capacitor between terminals of a power loop provides superior noise and transient suppression. The very short path between the capacitor and the active circuit provides for extremely low inductance, allowing for the use of relatively small capacitors. The semiconductor device then is connected to an electronic device such as a PC board for further connection to other circuitry. One particularly preferred mode of connection is by incorporating resilient, free-standing contact structures on the same semiconductor device, with the structures standing farther away from the semiconductor and the capacitor. Other useful connectors include providing similar resilient, free-standing contact structures on the other device, then positioning the semiconductor over the resilient contacts and securing the two devices together. A socket with such resilient structures is particularly useful for this application. In an alternative preferred embodiment, the capacitor and resilient contacts all are incorporated in the second device, such as a socket. In one aspect of the invention, the ancillary electrical component may include a travel stop structure which defines a minimum separation between the semiconductor and a substrate such as a printed circuit board.

Interconnect assemblies and methods including ancillary electronic component connected in immediate proximity of semiconductor device

A method of forming an interconnection, including a spring contact element, by lithographic techniques. In one embodiment, the method includes applying a masking material over a first portion of a substrate, the masking material having an opening which will define a first portion of a spring structure, depositing a structure material (e.g., conductive material) in the opening, and overfilling the opening with the structure material, removing a portion of the structure material, and removing a first portion of the masking material. In this embodiment, at least a portion of the first portion of the spring structure is freed of masking material. In one aspect of the invention, the method includes planarizing the masking material layer and structure material to remove a portion of the structure material. In another aspect, the spring structure formed includes one of a post portion, a beam portion, and a tip structure portion.

Method of making and using lithographic contact springs

Lithographic contact elements

A probe card assembly includes a probe card, a space transformer having resilient contact structures (probe elements) mounted directly thereto (i.e., without the need for additional connecting wires or the like) and extending from terminals on a surface thereof, and an interposer disposed between the space transformer and the probe card. The space transformer and interposer are &ldquo;stacked up&rdquo; so that the orientation of the space transformer, hence the orientation of the tips of the probe elements, can be adjusted without changing the orientation of the probe card. Suitable mechanisms for adjusting the orientation of the space transformer, and for determining what adjustments to make, are disclosed. The interposer has resilient contact structures extending from both the top and bottom surfaces thereof, and ensures that electrical connections are maintained between the space transformer and the probe card throughout the space transformer's range of adjustment, by virtue of the interposer's inherent compliance. Multiple die sites on a semiconductor wafer are readily probed using the disclosed techniques, and the probe elements can be arranged to optimize probing of an entire wafer. Composite interconnection elements having a relatively soft core overcoated by a relatively hard shell, as the resilient contact structures are described.

Probe card assembly and kit, and methods of using same

Temporary connections to spring contact elements extending from an electronic component such as a semiconductor device are made by urging the electronic component, consequently the ends of the spring contact elements, vertically against terminals of an interconnection substrate, or by horizontally urging terminals of an interconnection substrate against end portions of the spring contact elements. A variety of terminal configurations are disclosed.

Sockets for &ldquo;springed&rdquo; semiconductor devices

Spring contact elements are fabricated at areas on an electronic component remote from terminals to which they are electrically connected. For example, the spring contact elements may be mounted to remote regions such as distal ends of extended tails (conductive lines) which extend from a terminal of an electronic component to positions which are remote from the terminals. In this manner, a plurality of substantially identical spring contact elements can be mounted to the component so that their free (distal) ends are disposed in a pattern and at positions which are spatially-translated from the pattern of the terminals on the component. The spring contact elements include, but are not limited to, composite interconnection elements and plated-up structures. The electronic component includes, but is not limited to, a semiconductor device, a memory chip, a portion of a semiconductor wafer, a space transformer, a probe card, a chip carrier, and a socket.

Electronic component with terminals and spring contact elements extending from areas which are remote from the terminals

Spring contact elements are fabricated by depositing at least one layer of metallic material into openings defined in masking layers deposited on a surface of a substrate which may be an electronic component such as an active semiconductor device. Each spring contact element has a base end, a contact end, and a central body portion. The contact end is offset in the z-axis (at a different height) and in at least one of the x and y directions from the base end. In this manner, a plurality of spring contact elements are fabricated in a prescribed spatial relationship with one another on the substrate. The spring contact elements make temporary (i.e., pressure) or permanent (e.g., joined by soldering or brazing or with a conductive adhesive) connections with terminals of another electronic component to effect electrical connections therebetween. In an exemplary application, the spring contact elements are disposed on a semiconductor devices resident on a semiconductor wafer so that temporary connections can be made with the semiconductor devices to burn-in and/or test the semiconductor devices.

Method of making microelectronic spring contact elements

Deposition of metal in a preferred shape, including coatings on parts, or stand-alone materials, and subsequent heat treatment to provide improved mechanical properties. In particular, the method gives products with relatively high yield strength. The products often have relatively high elastic modulus, and are thermally stable, maintaining the high yield strength at temperatures considerably above 25.degree. C. This technique involves depositing a material in the presence of a selected additive, and then subjecting the deposited material to a moderate heat treatment. This moderate heat treatment differs from other commonly employed 'stress relief' heat treatments in using lower temperatures and/or shorter times, preferably just enough to reorganize the material to the new, desired form. Coating a shape and heat treating provides a shaped deposit with improved material properties. Coating a shape with a portion connected to a base and a portion detached therefrom can provide a resilient, conductive contact useful for electronic applications.

Method of making a product with improved material properties by moderate

Contact structures exhibiting resilience or compliance for a variety of electronic components are formed by bonding a free end of a wire to a substrate, configuring thw wire into a wire stem having a springable shape, serving thw wire stem, and overcoating the wire stem with at least one layer of a material chosen primarily for its structural (resiliency, compliance) characteristics. A variety of techniques for configuring, serving, and overcoating the wire stem are disclosed. In an exemplary embodiment, a free end of a wire stem is bonded to a contact area on a substrate, the wire stem is configured to ahve a springable shape, the wire stem is served to be free-standing by an electrical discharge, and the free-standing wire stem is overcoating by plating.

Method of modifying the thickness of a plating on a member by creating a

By segregating at least a substantial portion of the power connections to the space transformer component (506, 700, 800) from the signal connections thereto, constraints on the interposer component (504) may be relaxed. This is particularly advantageous in the context of probing one or more high power semiconductor components. The technique of the present invention provides for a plurality of signals (including power and ground) to be inserted into an electronic component such as a space transformer both from a one main surface thereof and an edge (periphery) thereof to an opposite main surface thereof. The space transformer includes pads (522, 706, 810) for engaging, by means of spring elements (524), component (508) to be tested and includes exposed edge pads (750, 804, 854) for engagement by a flexible cable (752) for transmission of power and ground signals to the space transformer. The system also includes an interposer (504) having resilient contacts (514, 516) for electrically interconnecting a probe card (502) to the space transformer (506).

Making discrete power connections to a space transformer of a probe card

Electronic components with terminals and spring contact elements

Sockets for 'springed' semiconductor devices

Resilient contact structures are mounted directly to bond pads on semiconductor dies, prior to the dies being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies to be exercised (e.g., tested and/or burned-in) in) by connecting to the semiconductor dies with a circuit board or the like having a plurality of terminals disposed on a surface thereof. Subsequently, the semiconductor dies may be singulated from the semiconductor wafer, whereupon the same resilient contact structures can be used to effect interconnections between the semiconductor dies and other electronic components (such as wiring substrates, semiconductor packages, etc.). Using the all-metallic composite interconnection elements of the present invention as the resilient contact structures, burn-in can be performed at temperatures of at least 150.degree. C., and can be completed in less than 60 minutes.

Wafer-level test and burn-in, and semiconductor process

Resilient contact structures are mounted directly to bond pads on semiconductor dies, prior to the dies being singulated (separated) from a semiconductor wafer. This enables the semiconductor dies to be exercised (e.g., tested and/or burned-in) by connecting to the semiconductor dies with a circuit board or the like having a plurality of terminals disposed on a surface thereof. Subsequently, the semiconductor dies may be singulated from the semiconductor wafer, whereupon the same resilient contact structures can be used to effect interconnections between the semiconductor dies and other electronic components (such as wiring substrates, semiconductor packages, etc.). Using the all-metallic composite interconnection elements of the present invention as the resilient contact structures, burn-in can be performed at temperatures of at least 150.degree. C., and can be completed in less than 60 minutes.

Growing community of inventors

Danville, CA, United States of America

Benjamin N Eldridge, Jr