Lsi Logic Corporation

Seng-Sooi Allen Lim

Chok J Chia

Qwai Hoong Low

Maniam B Alagaratnam

Manian Alagaratnam

Michael D Rostoker

Patrick J Variot

Owai H Low

A programmable substrate and a method of making a programmable substrate for use with array-type packages, including Ball Grid Arrays(BGA), Pin Grid Arrays (PGA) and Column Grid Arrays (CGA) includes a nonconductive programmable substrate with a cavity in the top of the substrate. The cavity is sized to receive an integrated circuit (IC) die. An array of electrically conductive vias pass through the substrate. A plurality of electrical traces are formed on the top of the substrate. The traces extend radially from an edge of the die cavity to the periphery of the substrate so as to pass between and near the vias. Each trace is electrically connected to a pad of the IC die by a wire bond. Each via is connected on a bottom surface of the substrate to a solder ball, pin, or other means for electrically and mechanically attaching the substrate to a printed circuit board. The traces are programmably connected to a selected via, e.g., using wire bonds between the trace and a nearby selected via, thereby allowing each pad of the IC die to be selectively connected to a desired via, and hence to a selected solder ball or pin.

Method for programming a substrate for array-type packages

A package for an integrated circuit is disclosed. The package comprises two layers (a top layer and a bottom layer) of flexible tape, each of which has a top surface and a bottom surface, with metal traces on the top surface. A die is mounted on top of the two layers and wire bonds connect bond pads on the die to metal traces on each of the two flexible tapes. The metal traces are routed along the top surfaces of the flexible tapes and are coupled to solder balls through holes in the tapes. These solder balls are mounted along the bottom of the package and serve as the electrical interface to a printed circuit board. Additional holes in the bottom layer tape allow solder balls to extend through the bottom layer tape so that they may be electrically coupled to traces on the top layer tape.

Multiple layer tape ball grid array package

One aspect of the invention relates to a flip-chip semiconductor package. In one version of the invention, the flip-chip semiconductor package includes a package substrate having an upper surface, a lower surface and a plurality of conductive traces, the upper surface having an upper plurality of electrical contacts coupled to the conductive traces, the lower surface having a lower plurality of electrical contacts coupled to the conductive traces, the lower plurality of electrical contacts being attachable to electrical contacts on a printed circuit board; a semiconductor die having an active surface and a non-active surface, the active surface having a plurality of circuit elements and a plurality of bond pads formed thereon, the bond pads being attached to the upper plurality of electrical contacts by solder bumps, the non-active surface having a plurality of grooves formed thereon; and a heat sink attached to the non-active surface of the semiconductor die.

Grooved semiconductor die for flip-chip heat sink attachment

One aspect of the invention relates to a semiconductor substrate. In one version of the invention, a semiconductor substrate includes a package substrate having first and second surfaces with conductive traces formed thereon and structures for providing electrical connection between selected conductive traces, a die attach area on the first surface of the package substrate adapted to provide physical connection to a semiconductor die, the die attach area having conductive contacts for providing electrical connection between the die and conductive traces on the first surface, a package frame, at least one substrate strap which connects the package substrate to the package frame, the substrate strap being formed integrally with the package substrate and the package frame.

Molded array integrated circuit package

Programmable substrate for array-type packages

A multiple-sized integrated circuit (IC) die and a method of making a multiple-sized IC die includes forming a plurality of IC dies on a semiconductor wafer. Each IC die has multiple rows of bonding pads around its periphery. Adjacent bonding pads on separate rows of each IC die are electrically connected together so that attachment to any one of the connected bond pads yields the same result. A plurality of scribe streets separate each IC die on the wafer, with the scribe street defining the width between each IC die. Rows of bonding pads reside in the scribe street area. Different rows of bonding pads may be selectively removed from the IC die by scribing the wafer so as to include one or more of the rows of bonding pads, thereby allowing one IC die design to have multiple sizes. An IC die separated from the wafer may still be sized smaller as long as there remain at least two rows of bonding pads around the periphery.

Multiple sized die

A semiconductor package (110) includes a tape substrate (135) having a top surface, a bottom surface, a plurality of conductive metal traces (115) formed on the top surface and a plurality of holes (130) arraigned in an array pattern formed through the tape substrate (135) exposing the conductive traces (115) from the bottom surface. A nonconductive metal plate or stiffener frame (155) attached to the bottom surface of the tape substrate (135) to support the tape substrate (135) during assembly. The stiffener frame (155) having through holes (160) corresponding to the holes (130) in the tape substrate (135) and being made from anodized aluminum, thus making it electrically nonconductive. An integrated circuit (IC) chip (120) is mounted on the top surface, opposite the stiffener frame (155). The IC chip (120) is in electrical connection to the traces (115) and a plurality of solder balls (125) are attached to the traces (115) through the holes (130 and 160), electrically connecting the semiconductor package (110) to a printed circuit board (170). Along with providing support for the tape substrate (135) during assembly, the stiffener frame (155) is used to improve the thermal performance of the semiconductor package (110) by dissipating the heat generated by the IC die (120) and improving the flatness of the finished semiconductor package (110).

Thermally enhanced tape ball grid array package

An apparatus and method for packaging an integrated circuit having a semiconductor die with electronic circuitry disposed thereon includes lead frames for mounting thereon solder balls of a ball grid array packaging structure. In one embodiment, the semiconductor die is coupled to conductors of the lead frame via gold wires attached to both the semiconductor die and the lead frame. The lead frame is encapsulated in plastic with apertures disposed therein for exposing upper and lower portions of conductors of the lead frame. The apertures are filled with solder balls to contact both the upper and lower portions of the lead frame conductors. Solder balls on the top of one integrated circuit package may be connected to mating solder balls on the bottom of another integrated circuit package, and so on, thereby achieving multiple stacking of integrated circuit packages.

Apparatus and method for stackable molded lead frame ball grid array

A semiconductor device and fabrication method are presented which advantageously combine TAB and wire bonding techniques to increase integrated circuit I/O pad density. The semiconductor device includes an integrated circuit, a substrate, and a carrier film (i.e., a TAB tape). The integrated circuit has a set of input/output (I/O) pads arranged upon an upper surface. The substrate has a die cavity within an upper surface and a set of bond traces arranged about the die cavity. An underside surface of the integrated circuit is attached to the substrate within the die cavity. The carrier film is positioned over the upper surface of the substrate such that the upper surface of the integrated circuit is exposed through a die aperture and portions of the members of the set of bond traces are exposed through corresponding members of a set of bond trace apertures. Each conductor has a first end connected to a member of the set of bond traces and an opposed second end connected to a corresponding member of a portion of the set of I/O pads. Each of the remaining members of the I/O pads are connected to respective bond traces adjacent to the die cavity by bonding wires. By combining TAB and wire bonding techniques, the number of I/O pads per unit of upper surface area of the integrated circuit may be increased.

Semiconductor device and fabrication method which advantageously combine

Substrates having a wide range of thickness, and intended to be overmolded with a plastic package body, are accommodated in a common mold. The top surface of the substrate is provided with a dam structure, which may be formed as an additional layer on the substrate, and which is preferably in the form of a square ring. A groove (channel) is machined (e.g., by routing) into the surface of the dam structure. The top mold half, having a cavity for forming the package body, is provided with a sealing structure at the periphery of the cavity. The sealing structure has a ridge fitting into the channel of the dam structure. The depth of the groove in the dam structure is readily adjusted to ensure uniform clamping pressure of the top mold half on the substrate, so that liquid molding compound is contained within the cavity and so that undue pressure is not exerted on the substrate.

Overmolded package body on a substrate

Method of improving molding of an overmolded package body on a substrate

A process of mounting a semiconductor device and leadframe to a printed circuit board are described. The device has a body, and a plurality of leads extending from the body. One or more alignment features are formed on the exterior of the package body, for maintaining precise alignment of the device with respect to a printed wiring board. The alignment feature is a tab formed as part of portion of the leadframe external to the package body. The tab may have various shapes, and may be provided with a hole for registering with a pin on an underlying substrate, such as a printed wiring board. The pin and the tab may be electrically connected.

Process for manufacturing and mounting a semiconductor device leadframe

A dambar-less leadframe is sandwiched between two printed circuit boards (PCBs). The PCBs form a major portion of the package body, and isolate the leadframe leads from plastic molding compound. In one embodiment, an upper PCB (substrate) is formed as a ring, having an opening containing a heat sink element. A lower PCB is also formed as a ring, and has a smaller opening for receiving a die. The back face of the die is mounted to the heat sink. The exposed front face of the die is wire bonded to inner ends of conductive traces on the exposed face of the lower PCB. The outer ends of the traces are electrically connected to the leadframe leads by plated-through vias extending through the two PCBs. The plated-through vias additionally secure the sandwich structure together. Plastic molding compound is injection/transfer molded over the front face of the die and the bond wires, forming a partially-molded package. In another embodiment, the upper PCB is a solid planar element. The back face of the die is mounted to the inside surface of the upper PCB. The die, die-receiving area, and/or package body shape have a 'certain non-square' shape (i.e., triangle, trapezoid, parallelogram, greatly-elongated rectangle, etc.).

Partially-molded, PCB chip carrier package for certain non-square die

A removable heatsink assembly comprised of a heatsink unit and a heatspreader is provided. The heatsink unit has at least one fin and a coupling collar for radiating heat away from a packaged electronic device. The heatspreader includes a platform attached to an inner collar in thermal contact with the packaged electronic device. The platform has one or more tabs suitable for mating with one or more flanges located on the coupling collar of the heatsink unit. Coupling grooves within the flanges engage the platform of the heatspreader when the flanges are mated with the heatspreader tabs and the heatsink is turned. The heatsink can therefore be quickly and conveniently attached to or removed from the heatspreader. The present invention thus permits a wide variety of different heatsinks to be interchangeably used with a single heatspreader attached to an electronic device package.

Method of cooling a packaged electronic device

A packaged semiconductor device, leadframe for making same, and method of mounting same to a printed circuit board are described. The device has a body, and a plurality of leads extending from the body. One or more alignment features are formed on the exterior of the package body, for maintaining precise alignment of the device with respect to a printed wiring board. The alignment feature is a tab formed as part of portion of the leadframe external to the package body. The tab may have various shapes, and may be provided with a hole for registering with a pin on an underlying substrate, such as a printed wiring board. The pin and the tab may be electrically connected.

Growing community of inventors

San Jose, CA, United States of America

Seng-Sooi Allen Lim