Lsi Logic Corporation

Robert T Trabucco

Chok J Chia

Patrick J Variot

Mark R Schneider

Sutee Vongfuangfoo

A method for mounting an integrated circuit includes a plurality of solder balls arrayed on the bottom surface of a package of the integrated circuit onto to a circuit board. These solder balls provide for surface mounting of the integrated circuit to a circuit board by solder reflow. The array of solder balls can be planarized so that each of the plural solder balls participate in defining a truly planar solder ball contact array for the integrated circuit package. Methods of manufacturing the integrated circuit with a package having planarized solder balls in an array dependent from a bottom surface thereof are set forth. The truly planarized solder ball contact array of the integrated circuit package affords nearly absolute reliability in forming of surface-mount electrical connections between the integrated circuit package and the circuit board on which the package is to mount. Additionally, the planarized solder ball contacts locally compensate individually for warpage of the integrated circuit package by variation in the individual dimensions of dependency of each solder ball below the bottom surface of the package.

Method for planarizing an array of solder balls

An integrated circuit includes a plurality of solder balls arrayed on the bottom surface of a package of the integrated circuit. These solder balls provide for surface mounting of the integrated circuit to a circuit board by solder reflow. The array of solder balls can be planarized so that each of the plural solder balls participate in defining a truly planar solder ball contact array for the integrated circuit package. Methods of manufacturing the integrated circuit with a package having planarized solder balls in an array dependent from a bottom surface thereof are set forth. The truly planarized solder ball contact array of the integrated circuit package affords nearly absolute reliability in forming of surface-mount electrical connections between the integrated circuit package and the circuit board on which the package is to mount. Additionally, the planarized solder ball contacts locally compensate individually for warpage of the integrated circuit package by variation in the individual dimensions of dependency of each solder ball below the bottom surface of the package.

Method for compensating for bottom warpage of a BGA integrated circuit

A fluxless method for fusing preformed solder balls to contact pads on a semiconductor package substrate wherein a masking plate having one or more vertical holes corresponding to the contact pads is placed over the package substrate, oxide-free solder balls are placed in the holes, the assembly is preheated to a temperature less than the melting point of the solder, and an energetic beam is directed onto the preformed solder balls to melt them and fuse them to the contact pads.

Fluxless solder ball attachment process

According to the present invention, a method is provided for attaching a package substrate to a circuit board. In one version of the invention, the package substrate has a semiconductor die disposed thereon, and the semiconductor die has a plurality of bond pads formed thereon which are electrically connected to conductive traces on the package substrate. In one embodiment of the invention, the method comprises the steps of attaching a first surface of an electrical connector to one of the conductive traces by thermoplastic adhesion; and attaching a second surface of the electrical connector to a conducting pad on the circuit board, also by thermoplastic adhesion.

Conductive polymer ball attachment for grid array semiconductor packages

A method for mounting an integrated circuit includes a plurality of solder balls arrayed on the bottom surface of a package of the integrated circuit on a circuit board. These solder balls provide for surface mounting of the integrated circuit to a circuit board by solder reflow. The array of solder balls can be planarized so that each of the plural solder balls participate in defining a truly planar solder ball contact array for the integrated circuit package. Methods of manufacturing the integrated circuit with a package having planarized solder balls in an array dependent from a bottom surface thereof are set forth. The truly planarized solder ball contact array of the integrated circuit package affords nearly absolute reliability in forming of surface-mount electrical connections between the integrated circuit package and the circuit board on which the package is to mount.

Method of planarizing an array of plastically deformable contacts on an

A planar substrate is attached to a face of a semiconductor die. The semiconductor die is electrically connected to a printed wiring board and encapsulation material covers the peripheral edges of the planar substrate, semiconductor die, and means for interconnecting the die and printed wiring board. An exterior face of the planar substrate remains exposed and may be utilized in pick and place automatic assembly. The exterior face of the planar substrate may also be utilized for attachment of an external heat sink for improved heat transfer from the semiconductor device. The planar substrate may be comprised of silicon, ceramic, metal or any other stiff material so long as the temperature coefficient of expansion is similar to that of the semiconductor die. A flip-chip semiconductor die may also be utilized without a planar substrate wherein the nonactive face of the die is exposed.

Semiconductor device package fabrication method and apparatus

A fixture clamps a plurality of lids onto a multi-chip module (MCM) integrated circuit for adhesively attaching the lids to cover a plurality of cavities in the module in which chips or dies are mounted. The fixture includes a base plate which is formed with recesses in which the lids and the module are fittingly retained with the lids properly positioned relative to the module. A pressure plate is guided onto the module by a pin assembly and presses the module against the base plate. A plurality of spring loaded clamps have first jaws that engage with the lids through respective holes in the base plate and second jaws that engage with the pressure plate. The clamp thereby clamps the lids and the pressure plate to the module. The assembly including the module, lids, pressure plate and clamps is then removed from the base plate to enable curing of an adhesive that bonds the lids to the module, and frees the base plate for reuse.

Fixture for attaching multiple lids to multi-chip module (MCM)

Integrated circuit having a coplanar solder ball contact array

A technique for simultaneously forming large numbers of solder ball (or bump) contacts on a surface of a substrate is described. A dissolvable film carrier is provided with holes arranged in a shape to correspond to an array of contact pads on a substrate. The holes are filled with solder. The film carrier retains the solder. The carrier is placed over the surface of the substrate and is heated, causing the solder to re-flow and to wet and to adhere to the contact pads. The carrier, which resists the re-flow temperature, maintains the shape of the solder contacts while cooling. After cooling, the film carrier can be removed from around the solder contacts with a suitable solvent.

Fabrication of a dissolvable film carrier containing conductive bump

A technique for simultaneously forming large numbers of solder ball (or bump) contacts on a surface of a substrate is described. A mold is provided for receiving a substrate. Recesses in the mold are shaped to form contacts of a desired size, and are arranged to align with contact pads on the surface of the substrate. When the substrate is inserted into the mold and the mold is closed, the contact pads align with the recesses. Molten solder is introduced into the recesses and, upon cooling, forms conductive raised bump contacts on the contact pads. The substrate is then removed from the mold. Various features of the invention are directed to forming 'tall' contacts with an aspect ratio (height to width ratio) of greater than 1:1, processing more than one substrate at a time, processing substrates of different sizes, and processing substrates with different contact patterns.

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Los Altos, CA, United States of America

Robert T Trabucco