A semiconductor chip having contacts on the periphery of its top surface is provided with an interposer overlying the central portion of the top surface. Peripheral contact leads extend inwardly from the peripheral contacts to central terminals on the interposer. The terminals on the interposer may be connected to a substrate using techniques commonly employed in surface mounting of electrical devices, such as solder bonding. The leads, and preferably the interposer, are flexible so that the terminals are movable with respect to the contacts on the chip, to compensate for differential thermal expansion of the chip and substrate. The terminals on the interposer may be disposed in an area array having terminals disposed at substantially equal spacings throughout the area of the interposer, thus providing substantial distances between the terminals while accommodating all of the terminals in an area approximately the same size as the area of the chip itself. The interposer may be provided with a compliant layer disposed between the terminals and the chip to permit slight vertical movement of the terminals towards the chip during testing operations. The chip and interposer assembly may be electrically tested prior to assembly to the substrate. A compliant layer disposed between the terminals and the chip permits slight vertical movement of the terminals towards the chip during testing operations, in which the terminals on the interposer are engaged with an assembly of test probes. The entire assembly is compact.

Semiconductor chip assemblies with fan-in leads

A semiconductor chip assembly is mounted to contact pads in a compact area array. An interposer is disposed between the chip and the substrate. The contacts on the chip are connected to terminals on the interposer by flexible leads extending through apertures in the interposer. The terminals on the interposer in turn are bonded to the contact pads on the substrate. Flexibility of the leads permits relative movement of the contacts on the chip relative to the terminals and the contact pads of the substrate and hence relieves the stresses caused by differential thermal expansion. The arrangement provides a compact structure similar to that achieved through flip-chip bonding, but with markedly increased resistance to thermal cycling damage.

Semiconductor chip assemblies having interposer and flexible lead

A microelectronic package includes a microelectronic element having faces and contacts, the microelectronic element having an outer perimeter, and a substrate overlying and spaced from a first face of the microelectronic element, whereby an outer region of the substrate extends beyond the outer perimeter of the microelectronic element. The microelectronic package includes a plurality of etched conductive posts exposed at a surface of the substrate and being electrically interconnected with the microelectronic element, whereby at least one of the etched conductive posts is disposed in the outer region of the substrate. The package includes an encapsulating mold material in contact with the microelectronic element and overlying the outer region of the substrate, the encapsulating mold material extending outside of the etched conductive posts for defining an outermost edge of the microelectronic package.

Microelectronic packages and methods therefor

Semiconductor chip assemblies incorporating flexible, sheet-like elements having terminals thereon overlying the front or rear face of the chip to provide a compact unit. The terminals on the sheet-like element are movable with respect to the chip, so as to compensate for thermal expansion. A resilient element such as a compliant layer interposed between the chip and terminals permits independent movement of the individual terminals toward the chip driving engagement with a test probe assembly so as to permit reliable engagement despite tolerances.

Semiconductor chip assemblies, methods of making same and components for same

A probe card assembly includes a probe card, a space transformer having resilient contact structures (probe elements) mounted directly to (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 “stacked up” 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 making same

Area array connector device (12) for providing electrical interconnection from contacts on a first printed circuit board surface (15) to corresponding contacts on a second opposed surface (17) consists of an electrically nonconductive support member (13) disposed between opposed board surfaces, the support member having apertures therethrough in regions of the support member generally corresponding to alignment of corresponding opposed pairs of contacts (34, 36), and electrically conductive metallic interconnect members (22) extending in elastomeric material in the regions. The metallic interconnect members extend through the elastomer, and have end surfaces (26, 28) exposed for metal-to-metal, electricity-conductive contact with the contacts, with total resistance between contacts less than about 25 milli-ohms. The member end surfaces deflect under pressure and are restored upon release of pressure, at least in part by the restorative effect of the elastomer. Preferably, the interconnect member is bodily-rotatable.

Electrical circuit board interconnect

A method of ablating fluoropolymer composition materials is presented wherein it has been found that small holes (less than 100 νm) can be formed in fluoropolymer composition laminate materials using UV lasers (10) to direct laser light through a mask (12) focusing lens (14) and onto fluoropolymer laminate (16). The resulting holes can be used to produce vias and plated through-holes having smooth side walls with little or no debris or residue remaining in holes and minimal damage to the polymer. Thus, the vias and plated through-holes can be plated without further cleaning processes. In addition, the holes are formed at a relatively fast rate.

Method of laser drilling fluoropolymer materials

A flexible circuit is presented having a flexing (cyclic bending) section of lower stiffness than adjacent parts of the circuit. The lower stiffness in the flexing section is achieved by reducing the thickness of the flexing section, either by omitting or removing some or all of the dielectric material of the flexible circuit in the flexing section, or by replacing conventional dielectric material in the flexing section with a polymer of lower modulus of elasticity.

Flexible circuit having flexing section of reduced stiffness, and method of manufacture thereof

Inductive devices, i.e., transformers, coils, inductors, etc. are produced from a rolled flexible circuit. The flexible circuit is comprised of a dielectric substrate having a circuit pattern thereon. The circuit pattern is configured such that, upon rolling, one or more coils is formed thereby defining an inductor, transformer, etc. Additionally, these inductive devices may be easily shielded using a ground plane in the flexible circuit. The rolled flexible circuit may be secured in several ways including an adhesive or by using a thermoplastic bonding layer which acts to heat seal the circuit together. The inductive devices of the present invention may be wrapped or rolled about a permeable core which improves inductance. Inductor devices manufactured in accordance with the present invention have the advantages of being small, surface mountable, inexpensive to manufacture and being capable of insertion onto printed wiring boards using automated insertion equipment. The small size of the inductor devices permit the present invention to take up only small areas on the circuit board thereby conserving valuable "real estate" on the printed wiring board.

Inductive devices for printed wiring boards

In accordance with the present invention, an MCM substrate product is manufactured in an additive process using multiple layers of a fluoropolymer composite material and copper The copper layers are plated, and the fluoropolymer composite layers are laminated A seeding process promotes reliable bonding between the fluoropolymer composite material and the plated copper The use of the filled fluoropolymeric composite eliminates the need for a barrier metal layer between the insulation and the conductors The MCM substrate device of the present invention may have multiple metal layers and multiple dielectric layers; four or five, or more, of each in a single structure would be easily achieved and is typical The structure would include lead lines in separate mutually orthogonal planes (sometimes referred to as "x" and "y" lead lines) sandwiched between ground and power voltage planes of copper The MCM substrate device of the present invention also has solid copper vias, which may be used either as electrical interconnection between layers of the MCM substrate and/or to the I/C's to be packaged in the module, or as thermal vias for heat conduction for thermal management The manufacturing process of the present invention makes it possible to start or stop any via in any layer of the device

Richard T. Traskos

Papers

Electrical circuit board interconnect

Method of laser drilling fluoropolymer materials

Flexible circuit having flexing section of reduced stiffness, and method of manufacture thereof

Inductive devices for printed wiring boards

Method of manufacture multichip module substrate