Fujitsu Corporation

David Kudzuma

Wen-chou Vincent Wang

Solomon I Beilin

William T Chou

Michael G Lee

Michael G Peters

James J Roman

Som S Swamy

Larry Louis Moresco

Teruo Murase

David A Horine

Michael M Lee

Alexei L Glebov

A hybrid integration process for fabrication of an optical cross-connect switching apparatus. The switching element is based on the deflection of light beam in electro-optic materials by applying electric field across electrodes of an appropriate configuration. The integration process includes fabrication of a substrate (e.g. silicon substrate) with 2D imaging optics from polymeric materials (or silica), fabrication of the light deflecting element, and assembly of the deflecting element on the substrate with imaging optics. The fabrication of the light deflecting element includes fabrication of a LN (lithium niobate) block. The LN block assembled in an optical switching apparatus includes a two-dimensional waveguide formed on a surface of the LN block and an electrode on a surface of the LN block.

Optical switching apparatus and method for fabricating

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 interconnecting post for mounting a microelectronic device such as an integral circuit chip is fabricated with generally uniform cross-section, by forming a first layer of positive photoresist on a substrate, soft-baking that first layer and exposing it for a short time with a wide-apertured mask or simply a UV blank flood exposure. Without developing the first layer, a second layer of positive resist is then applied over the first layer, soft-baked, and then exposed with a narrow-apertured mask. During the soft-baking of the second layer, some of its activator in the photoresist compound diffuses into the exposed portion of the first layer and modifies its solubility in such a way that, when the layers are subsequently developed, the developer partially undercuts the unexposed portion of the first layer to form in the photoresist an opening of generally uniform cross-section. This opening can then be filled by plating to produce a strong, integral interconnect post.

Structure and fabrication procedure for a stable post

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

Fabrication procedure for a stable post

Methods for pretreating patterned masks layers, such as photoresist masks, with electron-beam radiation for use in high temperature processes are disclosed. The electron-beam exposure deactivates compounds within the mask material which would ordinarily decompose and produce gasses within the photoresist layer. The gasses cause blistering in the untreated photoresist layer, which in turn degrades the dimensional integrity of the untreated layer.

Electron-beam treatment procedure for patterned mask layers

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

San Jose, CA, United States of America

David Kudzuma