Fujitsu Corporation

Fijitsu Limited

Som S Swamy

Solomon I Beilin

James J Roman

Michael G Lee

Wen-chou Vincent Wang

William T Chou

Michael G Peters

David Kudzuma

Teruo Murase

Larry Louis Moresco

Lei Zhang

David Dung Ngo

Methods and articles used to fabricate flexible circuit structures are disclosed. The methods include depositing a release layer on substrate, and then forming a conductive laminate on the release layer. After the release layer is formed, the conductive laminate can be easily separated by the substrate to eventually form a flexible circuit structure.

Methods for fabricating flexible circuit structures

Normally, a positive photoresist is developed with an alkaline aqueous solution to form patterns, and is subsequently stripped with an organic solvent after the photoresist has served its function. Such strippers are relatively toxic and damaging to the environment, and cannot be handled by standard (community) waste-water treatment facilities. These strippers cannot be easily neutralized, and must be disposed of in a highly specialized and relatively expensive manner. The present invention provides a method of treating positive and negative photoresists during their usage as photo masks such that the photoresists may be removed by less toxic chemicals which can be readily neutralized and handled by conventional waste water treatment facilities.

Environmentally friendly removal of photoresists used in wet etchable

An interposer substrate for mounting an integrated circuit chip to a substrate, and method of making the same, are shown. The interposer substrate comprises power supply paths and controlled impedance signal paths that are substantially isolated from each other. Power supply is routed through rigid segments and signals are routed through a thin film flexible connector that runs from the upper surface of the interposer substrate to the lower surface. Bypass capacitance is incorporated into the interposer substrate and connected to the power supply so that it is positioned very close to the integrated circuit chip. The interposer may be fabricated by forming a multilayered thin film structure including the signal paths over a rigid substrate having vias formed therein, removing the central portion of the substrate leaving the two end segments, and folding and joining the end segments such that the vias are connected. In another embodiment of the invention, a separate power plate is provided for carrying the power lines. Portions of the power plate, with a multilayered thin film structure thereon, are cut and folded to form interposers. Methods of making single-chip interposers are also disclosed.

Controlled impedance interposer substrate and method of making

An interposer substrate for mounting an integrated circuit chip to a substrate, and method of making the same, are shown. The interposer substrate comprises power supply paths and controlled impedance signal paths that are substantially isolated from each other. Power supply is routed though rigid segments and signals are routed though a thin film flexible connector that runs from the upper surface of the interposer substrate to the lower surface. Bypass capacitance is incorporated into the interposer substrate and connected to the power supply so that it is positioned very close to the integrated circuit chip. The interposer may be fabricated by forming a multilayered thin film structure including the signal paths over a rigid substrate having vias formed therein, removing the central portion of the substrate leaving the two end segments, and folding and joining the end segments such that the vias are connected. In another embodiment of the invention, a separate power plate is provided for carrying the power lines. Portions of the power plate, with a multilayered thin film structure thereon, are cut and folded to form interposers. Methods of making single-chip interposers are also disclosed.

Controlled impedence interposer substrate

A multichip module substrate for use in a three-dimensional multichip module, and methods of making the same, are disclosed. The substrate comprises a thin film structure, for routing signals to and from integrated circuit chips, formed over a rigid support base. Apertures are formed in the support base exposing the underside of the thin film structure, thereby allowing high density connectors to be mounted on both surfaces of the thin film structure, greatly enhancing the ability to communicate signals between adjacent substrates in the chip module. This avoids the need to route the signals either through the rigid support base or to the edges of the thin film structure. Power and ground, which do not require a high connection density, are routed in low impedance paths through the support base. Preferably, the thin film structure is made of alternating layers of patterned metal, such as copper, and a low dielectric organic polymer, such as a polyimide.

Method of making a multichip module substrate

Multichip module substrate

A three dimensional thin-film interconnector is fabricated by depositing a dielectric layer onto the surface of a substrate, depositing a layer of conductive material onto the dielectric layer to form a signal plane, depositing a dielectric layer onto the surface of the signal plane, forming a plurality of through holes in the dielectric layer that extend to the signal plane, and filling the through holes with an electrically conductive material to form vias. The sequence of forming a signal plane, depositing a dielectric layer, forming a plurality of through holes, and filling the through holes is repeated until a predetermined number of signal planes and a predetermined arrangement of vias are obtained. The through holes are formed at locations in the dielectric layers corresponding to both predetermined electrical connections and the vias in a preceding dielectric layer. The signal planes are formed at different locations on the substrate. The sequence of signal planes and dielectric layers at the same location on the substrate form a signal plane set which defines a connector. Contact pads are deposited onto the surface of a final dielectric layer and electrically connect with each via. Wires are used to electrically connect the contact pads of one connector to corresponding contact pads of another connector. A portion of the substrate and dielectric layers not comprising a signal plane set is removed, forming electrical connectors flexibly attached by the plurality of wires.

Growing community of inventors

Danville, CA, United States of America

Som S Swamy