Staktek Corporation

Staktek Group L.p.

Other

Carmen D Burns

James W Cady

Jerry Mark Roane

Phillip R Troetschel

David Roper

James G Wilder

Julian Dowden

Philip R Troetschel

The present invention provides a flexible circuit connector for electrically coupling IC devices to one another in a stacked configuration. Each IC device includes: (1) a package having top, bottom, and peripheral sides; and (2) external leads that extend out from at least one of the peripheral sides. In one embodiment, the flexible circuit connector comprises a plurality of discrete conductors that are adapted to be mounted between the upper side of a first package and the lower side of a second package. The flexible circuit connector also includes distal ends that extend from the conductors. The distal ends are adapted to be electrically connected to external leads from the first and second packages to interconnect with one another predetermined, separate groups of the external leads. In this manner, individual devices within a stack module can be individually accessed from traces on a circuit card. This flexible capability is beneficial in modules such as memory modules with multiple, stacked memory devices.

Flexible circuit connector for stacked chip module

The present invention provides a method and apparatus for fabricating densely stacked ball-grid-array packages into a three-dimensional multi-package array. Integrated circuit packages are stacked on one another to form a module. Lead carriers provide an external point of electrical connection to buried package leads. Lead carriers are formed with apertures that partially surround each lead and electrically and thermally couple conductive elements or traces in the lead carrier to each package lead. Optionally thin layers of thermally conductive adhesive located between the lead carrier and adjacent packages facilitates the transfer of heat between packages and to the lead carrier. Lead carriers may be formed of custom flexible circuits having multiple layers of conductive material separated by a substrate to provide accurate impedance control and providing high density signal trace routing and ball-grid array connection to a printed wiring board.

High density integrated circuit module

A system and method for selectively stacking and interconnecting individual integrated circuit devices to create a high density integrated circuit module. Connections between stack elements are made through carrier structures that provide inter-element connections that substantially follow an axis that is substantially perpendicular to the vertical axis of the stack. The carrier structure provides connection between elements through conductive paths disposed to provide connection between the foot of an upper IC element and the upper shoulder of the lower IC element. This leaves open to air flow most of the vertical transit section of the lower lead for cooling while creating an air gap between elements that encourages cooling airflow between the elements of the stack. A method for creating stacked integrated circuit modules according to the invention is provided.

Stacking system and method

Integrated circuit modules made in accordance with the methods of the present invention have multiple Ball-Grid Array (BGA) packages mounted to a substantially planar support substrate. Each package is inclined at an angle to the support substrate and partially overlaps another package. The first package or row of packages overlaps a wedge that is provided for support. A flexible substrate is mounted to each BGA package and has a portion that extends away from the package to adhere to the support substrate, for communication between each package and signal lines on the support substrate. Optionally, a portion of the substrate that extends away from the integrated circuit package can be bent back at a 180&deg; angle to allow the pads on the top surface of the flexible substrate to attach to mating pads on the support substrate. Precise control of the impedance of select signal traces is accomplished through the use of ground traces that run parallel with the select signal, a ground plane layer, and alternating signal-substrate mounting pads with GND-substrate mounting pads. One aspect of the present invention has the package leads located in close proximity to one side of the package for optimally short trace lengths. Another aspect provides a method for routing signals for optimal signal length and elimination of stubs. A preferred embodiment of a flexible substrate has an accordion portion formed in the flexible substrate to provide elasticity for preventing stretching and distortions of the flexible substrate during automated assembly. A method is provided for connecting signals lines of each flexible substrate in series. Various embodiments of package lead mounting pads formed in the flexible substrate that provide electrical and thermal coupling to package leads including ring-shaped pads, flexible tabs, and apertures for removing flux, excess solder, and debris.

Stacked micro ball grid array packages

A high density integrated circuit module having complex electrical interconnection is described, which includes a plurality of stacked level-one integrated circuit devices, wherein each level-one device includes an integrated circuit die and a plurality of electrical leads extending from the die; and a plurality of non-linear rails adapted to electrically and thermally interconnect selected leads of selected stacked level-one devices within the module, wherein at least some of the plurality of non-linear rail include a lead interconnect portion which is adapted to at most partially surround and receive a selected lead from one of the stacked level-one devices. Other embodiments include TSOP modules having leads reduced in width to allow additional selected non-linear rails to interconnect with select leads in the module. Strain relief for the rail/circuit board substrate connection in harsh environment applications is also provided.

High density integrated circuit module with complex electrical interconnect rails having electrical interconnect strain relief

Method of manufacturing a surface mount package

The present invention provides a method for fabricating modified integrated circuit packages that are ultra-thin and resist warping. The integrated circuit packages are made thinner by removing some of the casing material uniformly from the upper and lower major surfaces of the integrated circuit package. To prevent the resulting ultra-thin integrated circuit package from warping, a thin layer of material with a coefficient of thermal expansion less than that of silicon is mounted to the upper major surface of the package after some of the casing material has been removed uniformly from the upper major surface. Also, a thin layer of material with a coefficient of thermal expansion greater than that of silicon may be mounted to the lower major surface of the package after some of the casing material has been removed uniformly from the lower major surface. The result is an ultra-thin integrated circuit package that is thermally and mechanically balanced to prevent warping.

Warp-resistent ultra-thin integrated circuit package fabrication method

An integrated circuit package for improved warp resistance and heat dissipation is described. The LOC package includes: an integrated circuit die having an upper, active face, and a multi-layered, substantially planar lead frame mounted to the active face of the die, where the lead frame is preferably comprised of layers configured as Cu/INVAR/Cu or Cu/Alloy,/Cu. The choice of the middle layer of the lead frame is selected to minimize the warping forces on the package such that the coefficient of thermal expansion of the composite lead frame approximates that of silicon. The copper layers of the lead frame provide improved heat dissipation.

Method of manufacturing a warp resistant thermally conductive circuit package

Thin and durable level-one and level-two integrated circuit packages are provided. A thin and durable level-one package is achieved in one method involving a molding technique of evenly applying molding compound to an integrated circuit die element. The casing surrounding a die element may be reduced or eliminated in part to thin the level-one package provided any necessary steps are taken to ensure the integrity of the package. Moisture-barriers, as an example, may be provided to the upper and/or lower surfaces of the thin level-one package. Additionally, a thin level-one package may also be constructed with one or more metal layers to prevent warpage. These level-one packages may be aligned in a stacked configuration to form a thin and durable horizontal level-two package. Various thermal conductors may be thermally coupled to the level-two package to help dissipate heat.

Ultra high density integrated circuit packages

The present invention is a rail-less bus system for a high density integrated circuit package, or module, made up of a plurality of vertically stacked high density integrated circuit devices. Each device has leads extending therefrom with bifurcated or trifurcated distal lead ends which electrically connect with lead ends of adjacent integrated circuit devices. The bus system provides a path for communication from the module to external electronic devices and internal communication between the individual integrated circuit devices in the module.

Integrated circuit packages having an externally mounted lead frame

Method of making high density integrated circuit module

An integrated circuit package for improved warp resistance and heat dissipation is described. The LOC package includes: an integrated circuit die having an upper, active face, and a multi-layered, substantially planar lead frame mounted to the active face of the die, where the lead frame is preferably comprised of layers configured as Cu/INVAR/Cu or Cu/Alloy 42/Cu. The choice of the middle layer of the lead frame is selected to minimize the warping forces on the package such that the coefficient of thermal expansion of the composite lead frame approximates that of silicon. The copper layers of the lead frame provide improved heat dissipation.

Growing community of inventors

Austin, TX, United States of America

Carmen D Burns