Abstract:
Structures and methods to reduce maximum current density in a solder ball are disclosed. A method includes forming a contact pad in a last wiring level and forming a plurality of wires of the contact pad extending from side edges of the contact pad to respective ones of a plurality of vias. Each one of the plurality of wires has substantially the same electrical resistance.
Abstract:
Methods, apparatus and assemblies for enhancing heat transfer in electronic components using a flexible thermal pillow. The flexible thermal pillow has a thermally conductive material sealed between top and bottom conductive layers, with the bottom layer having a flexible reservoir residing on opposing sides of a central portion of the pillow that has a gap. The pillow may have roughened internal surfaces to increase an internal surface area within the pillow for enhanced heat dissipation. In an electronic assembly, the central portion of the pillow resides between a heat sink and heat-generating component for the thermal coupling there-between. During thermal cycling, the flexible reservoir of the pillow expands to retain thermally conductive material extruded from the gap, and then contracts to force such extruded material back into the gap. An external pressure source may contact the pillow for further forcing the extruded thermally conductive material back into the gap.
Abstract:
CTE differentials between chips and organic dielectric carriers, boards or other substrates to which the chips are attached are accommodated with a layer of a thermoplastic material, preferably a thermotropic polymer whose physical properties can be altered by extrusion or other physical processes, such as liquid crystalline polyesters, that modifies the CTE of at least one component of the package and thereby reduces CTE differentials. The material may be applied to the entire surface of a chip carrier, printed circuit or other substrate, or form an interior layer of a multi-layered structure. It may also be applied to selected regions or areas on the surface of a carrier or other substrate where adjustment is required.
Abstract:
A flexible interconnect for flexibly connecting an integrated circuit chip to a substrate. The flexible interconnect includes a flexible core, formed of a polymeric material, fully covered by a layer of an electrically conductive metal. A layer of a compliant material is provided beneath the input/output pad of the substrate and/or integrated circuit chip to reduce mechanical stresses on the flexible interconnect. The substrate and integrated circuit chip may include depressions to receive ends of the flexible interconnect. In one embodiment, the flexible interconnect may be tubular in shape and positioned on a protrusion formed on the substrate.
Abstract:
An LGA structure is provided having at least one semiconductor device over a substrate and a mechanical load apparatus over the semiconductor device. The structure includes a load-distributing material between the mechanical load apparatus and the substrate. Specifically, the load-distributing material is proximate a first side of the semiconductor device and a second side of the semiconductor device opposite the first side of the semiconductor device. Furthermore, the load-distributing material completely surrounds the semiconductor device and contacts the mechanical load apparatus, the substrate, and the semiconductor device. The load-distributing material can be thermally conductive and comprises an elastomer and/or a liquid. The load-distributing material comprises a LGA interposer adapted to connect the substrate to a PCB below the substrate and/or a second substrate. Moreover, the load-distributing material comprises compressible material layers and rigid material layers. The load-distributing material comprises a rigid material incased in a compressible material.
Abstract:
A method of removing a metal skin from a through-hole surface of a copper-Invar-copper (CIC) laminate without causing differential etchback of the laminate. The metal skin includes debris deposited on the through-hole surface as the through hole is being formed by laser or mechanical drilling of a substrate that includes the laminate as an inner plane. Removing the metal skin combines electrochemical polishing (ECP) with ultrasonics. ECP dissolves the metal skin in an acid solution, while ultrasonics agitates and circulates the acid solution to sweep the metal skin out of the through hole. ECP is activated when a pulse power supply is turned on and generates a periodic voltage pulse from a pulse power supply whose positive terminal is coupled to the laminate and whose negative terminal is coupled to a conductive cathode. After the metal skin is removed, the laminate is differentially etched such that the copper is etched at a faster rate than the Invar. To prevent the differential etching, a copper layer is formed on a surface of the substrate with an electrical resistance R1 between the copper layer and the positive terminal of the pulse power supply. Additionally, an electrical resistance R2 is formed between the laminate and the positive terminal of the pulse power supply. Adjustment of R1 and R2 controls the relative etch rates of the copper and the Invar.
Abstract:
Sloped vias are formed in a resinous layer made from a material which is curable in stages, which can be coated on a substrate prior to partial curing, which adheres to the substrate and which shrinks upon full curing by a process which includes first using a dry, directional etch to form straight walled vias in a partially cured layer of the material coated on the substrate and then fully curing the layer. The straight walled vias are changed to sloped vias during final cure when adhesive contact between the substrate and the layer of resinous material inhibits shrinking of the side of the resinous layer which contacts the substrate, while the unsupported side of the layer is free to shrink. Such sloped vias are observed to improve the integrity of conductive coatings placed in the vias by reducing cracking, peeling and flaking thereof. Sloped vias with conductive coatings are useful in the construction of computer components.
Abstract:
Contaminant is removed from holes by etching in a gaseous plasma by first removing contaminant from the vicinity of the edges of the hole. Next, a mask is provided in the vicinity of the edges to prevent etching by contacting with a gaseous plasma which is different from the gaseous plasma employed in the first etching step. The holes are then etched in a gaseous plasma to remove contaminant from the interior of the holes in the vicinity of the center of the holes, whereby the mask protects the edges from being etched.
Abstract:
An LGA structure is provided having at least one semiconductor device over a substrate and a mechanical load apparatus over the semiconductor device. The structure includes a load-distributing material between the mechanical load apparatus and the substrate. Specifically, the load-distributing material is proximate a first side of the semiconductor device and a second side of the semiconductor device opposite the first side of the semiconductor device. Furthermore, the load-distributing material completely surrounds the semiconductor device and contacts the mechanical load apparatus, the substrate, and the semiconductor device. The load-distributing material can be thermally conductive and comprises an elastomer and/or a liquid. The load-distributing material comprises a LGA interposer adapted to connect the substrate to a PCB below the substrate and/or a second substrate. Moreover, the load-distributing material comprises compressible material layers and rigid material layers. The load-distributing material comprises a rigid material incased in a compressible material.
Abstract:
Methods, apparatus and assemblies for enhancing heat transfer in electronic components using a flexible thermal pillow. The flexible thermal pillow has a thermally conductive material sealed between top and bottom conductive layers, with the bottom layer having a flexible reservoir residing on opposing sides of a central portion of the pillow that has a gap. The pillow may have roughened internal surfaces to increase an internal surface area within the pillow for enhanced heat dissipation. In an electronic assembly, the central portion of the pillow resides between a heat sink and heat-generating component for the thermal coupling there-between. During thermal cycling, the flexible reservoir of the pillow expands to retain thermally conductive material extruded from the gap, and then contracts to force such extruded material back into the gap. An external pressure source may contact the pillow for further forcing the extruded thermally conductive material back into the gap.