Abstract: The present invention stacks integrated circuits into modules that conserve board surface area. In a two-high stack or module devised in accordance with a preferred embodiment of the present invention, a pair of integrated circuits is stacked, with one integrated circuit above the other. The two integrated circuits are connected with a pair of flexible circuit structures. Each of the pair of flexible circuit structures is partially wrapped about a respective opposite lateral edge of the lower integrated circuit of the module. The flex circuit pair connects the upper and lower integrated circuits and provides a thermal and electrical path connection path between the module and an application environment such as a printed wiring board (PWB). The present invention may be employed to advantage in numerous configurations and combinations of integrated circuits in modules provided for high-density memories or high capacity computing.

Abstract: The present invention stacks chip scale-packaged integrated circuits (CSPs) into modules that conserve board surface area. In a two-high CSP stack or module devised in accordance with a preferred embodiment of the present invention, a pair of CSPs is stacked, with one CSP above the other. The two CSPs are connected with a pair of flexible circuit structures. Each of the pair of flexible circuit structures is partially wrapped about a respective opposite lateral edge of the lower CSP of the module. The flex circuit pair connects the upper and lower CSPs and provides a thermal and electrical connection path between the module and an application environment such as a printed wiring board (PWB). The present invention may be employed to advantage in numerous configurations and combinations of CSPs in modules provided for high-density memories or high capacity computing.

Abstract: 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.

Abstract: The present invention stacks packaged integrated circuits into modules that conserve PWB or other board surface area. The invention provides techniques and structures for aggregating chip scale-packaged integrated circuits (CSPs) or leaded packages with other CSPs or with monolithic or stacked leaded packages into modules that conserve PWB or other board surface area. The present invention can be used to advantage with CSP or leaded packages of a variety of sizes and configurations ranging from larger packaged base elements having many dozens of contacts to smaller packages such as, for example, die-sized packages such as DSBGA. In a preferred embodiment devised in accordance with the present invention, a base element IC and a support element IC are aggregated through a flex circuit having at least two conductive layers that are patterned to selectively connect the two IC elements.

Abstract: A system and method for selectively stacking and interconnecting individual integrated circuit devices to create a high-density integrated circuit module. In a preferred embodiment, conventional thin small outline packaged (TSOP) memory circuits are vertically stacked one above the other. The constituent IC elements act in concert to provide an assembly of memory capacity approximately equal to the sum of the capacities of the ICs that constitute the assembly. The IC elements of the stack are electrically connected through individual contact members that connect corresponding leads of IC elements positioned adjacently in the stack. In a preferred embodiment, the contact members are composed of lead frame material. Methods for creating stacked integrated circuit modules are provided that provide reasonable cost, mass production techniques to produce modules.

Abstract: A system and method for selectively stacking and interconnecting individual integrated circuit devices to create a high-density integrated circuit module. In a preferred embodiment, conventional thin small outline packaged (TSOP) memory circuits are vertically stacked one above the other. The constituent IC elements act in concert to provide an assembly of memory capacity approximately equal to the sum of the capacities of the ICs that constitute the assembly. The IC elements of the stack are electrically connected through individual contact members that connect corresponding leads of IC elements positioned adjacently in the stack. In a preferred embodiment, the contact members are composed of lead frame material. Methods for creating stacked integrated circuit modules are provided that provide reasonable cost, mass production techniques to produce modules.

Abstract: The RAMBUS compatible configuration of the present invention is achieved by stacking one of the two modules in the stacked configuration in an upside-down position with respect to the other. This way, the corresponding electrical leads of each memory module will extend on opposite sides of the stacked package and will be securably connected to vertical rails. The vertical rails are electrically and securably connected to the bonding pads which electrically connect to the RAMBUS signal channel. In this embodiment, the electrical leads of one memory module electrically connect to the signal channel at points located on one side of the stacked package and the electrical leads of the other memory module connect to the signal channel at points located on the opposite side of the stacked package. The resulting distance between the points of contact between corresponding leads of each memory module in the stacked package is sufficient to satisfy the requirements of the RAMBUS signal channel.

Abstract: 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° angle to allow the pads on the top surface of the flexible substrate to attach to mating pads on the support substrate.

Abstract: 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.

Abstract: A clock driver providing a clock signal, from an input clock signal, that has instantaneously selectable phase and methods for synchronizing data transfers in a multi-signal bus communication system. A clock driver of the present invention generates an output clock signal from an input clock signal having a periodic wave form and provides the flexibility for selecting or changing the magnitude of the phase-offset of the output clock signal, in relationship to the input clock signal, for desired clock periods and optionally desired half-clock periods. A method is provided for the self-calibration of critical delay elements. The present invention also includes a method for synchronizing data transfers between a bus master device that is clocked by a system clock and a plurality of synchronous DRAM devices (SDRAM) that are clocked by a local clock; the local clock has, in relationship to the system clock signal, a first phase-offset for read cycles and a second phase-offset for write cycles.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.