Abstract: Methods for minimizing warpage of a welded foil carrier structure used in the packaging of integrated circuits are described. Portions of a metallic foil are ultrasonically welded to a carrier to form a foil carrier structure. The ultrasonic welding helps define a panel in the metallic foil that is suitable for packaging integrated circuits. Warpage of the thin foil can be limited in various ways. By way of example, an intermittent welding pattern that extends along the edges of the panel may be formed. Slots may be cut to define sections in the foil carrier structure. Materials for the metallic foil and the carrier may be selected to have similar coefficients of thermal expansion. An appropriate thickness for the metallic foil and the carrier may be selected, such that the warpage of the welded foil carrier structure is limited when the foil carrier structure is subjected to large increases in temperature. Foil carrier structures for use in the above methods are also described.

Abstract: The present invention relates to methods and arrangements for using a thin foil to form electrical interconnects in an integrated circuit package. One such arrangement involves a foil carrier structure, which includes a foil adhered to a carrier having cavities. Some methods of the present invention involve attaching dice to the foil and encapsulating the foil carrier structure in a molding material. In one embodiment, the molding material presses against the foil, which causes portions of the foil to distend into the cavities of the carrier. As a result, recessed and raised areas are formed in the foil. Afterwards, the carrier is removed and portions of the raised areas in the foil are removed through one of a variety of techniques, such as grinding. This process helps define and electrical isolate contact pads in the foil. The resulting molded foil structure may then be singulated into multiple semiconductor packages.

Abstract: An integrated circuit package is described that includes an integrated circuit die, a plurality of lower contact leads, and an insulating substrate positioned over the die and lower contact leads. The insulating substrate includes a plurality of electrically conducting upper routing traces formed on the bottom surface of the substrate. The traces on the bottom surface of the substrate electrically couple each lower contact lead with an associated I/O pad.

Abstract: In one aspect of the invention, a method of attaching a semiconductor die to a microarray leadframe is described. The method comprises stamping an adhesive onto discrete areas of the microarray leadframe using a multi-pronged stamp tool. The adhesive is applied to the leadframe as a series of dots, each dot corresponding to an associated prong of the stamping tool. In some embodiments the adhesive used to attach the semiconductor die to a leadframe is a black epoxy based adhesive material. In an apparatus aspect of the invention, lead traces in a microarray leadframe are arranged to have tails that extend beyond their associated contact posts on the side of the contact post that is opposite a wire bonding region such that such lead traces extends on two opposing sides of their associated contact posts. The tails do not attach to other structures within the lead frame (such as a die attach structure).

Abstract: An integrated circuit package is described that includes two dice. The active surface of each die includes a plurality of I/O pads. The active surface of the first die is positioned adjacent first surfaces of the leads of a lead frame such that I/O pads from the first die are arranged adjacent corresponding solder pad surfaces on the first surfaces. Similarly, the active surface of the second die is positioned adjacent second surfaces of the leads opposite the first surfaces such that I/O pads from the second die are arranged adjacent corresponding solder pad surfaces on the second surfaces. A plurality of solder joints are arranged to physically and electrically connect I/O pads from the first or second die to associated adjacent solder pad surfaces on the leads. In this way, a single lead frame can be utilized to package two dice, one on either side of the leads of the leadframe.

Abstract: A method of packaging an integrated circuit die having a plurality of I/O pads is described. The method includes positioning the die within a die attach area of a first leadframe that includes a plurality of first leads. The method also includes positioning a second leadframe that includes a plurality of second leads over the first leadframe. The method further includes electrically connecting each of the second leads to both an associated I/O pad and a first lead.

Abstract: In one aspect of the invention, a method of attaching a semiconductor die to a microarray leadframe is described. The method comprises stamping an adhesive onto discrete areas of the microarray leadframe using a multi-pronged stamp tool. The adhesive is applied to the leadframe as a series of dots, each dot corresponding to an associated prong of the stamping tool. In some embodiments the adhesive used to attach the semiconductor die to a leadframe is a black epoxy based adhesive material. In an apparatus aspect of the invention, lead traces in a microarray leadframe are arranged to have tails that extend beyond their associated contact posts on the side of the contact post that is opposite a wire bonding region such that such lead traces extends on two opposing sides of their associated contact posts. The tails do not attach to other structures within the lead frame (such as a die attach structure).

Abstract: A leadframe suitable for use in the packaging of at least two integrated circuit dice into a single integrated circuit package is described. The leadframe includes a plurality of leads. Each of a first set of the plurality of leads has a first side and a second side substantially opposite the first side of the lead. Additionally, each of the first and second sides of the first set of leads each include at least two solder pads. Each solder pad on a lead of the first set of leads is isolated from other solder pads on the same side of the lead with at least one recessed region adjacent the solder pad. In various embodiments, I/O pads from at least two dice are physically and electrically connected to the opposing sides of the leads.

Abstract: An integrated circuit package is described that includes two dice. The active surface of each die includes a plurality of I/O pads. The active surface of the first die is positioned adjacent first surfaces of the leads of a leadframe such that I/O pads from the first die are arranged adjacent corresponding solder pad surfaces on the first surfaces. Similarly, the active surface of the second die is positioned adjacent second surfaces of the leads opposite the first surfaces such that I/O pads from the second die are arranged adjacent corresponding solder pad surfaces on the second surfaces. A plurality of solder joints are arranged to physically and electrically connect I/O pads from the first or second die to associated adjacent solder pad surfaces on the leads. In this way, a single leadframe can be utilized to package two dice, one on either side of the leads of the leadframe.

Abstract: A method of packaging an integrated circuit die having a plurality of I/O pads is described. The method includes positioning the die within a die attach area of a first leadframe that includes a plurality of first leads. The method also includes positioning a second leadframe that includes a plurality of second leads over the first leadframe. The method further includes electrically connecting each of the second leads to both an associated I/O pad and a first lead.

Abstract: Integrated circuit (IC) packages are described. Each IC package includes a die having an exposed metallic layer deposited on its back surface. Solder joints are arranged to physically and electrically connect I/O pads on the active surface of the die with associated leads. A molding material encapsulates portions of the die, leadframe and solder joint connections while leaving the metallic layer exposed and uncovered by molding material.

Abstract: A method of handling an IC wafer that includes a multiplicity of dice is described. Solder bumps are formed on bond pads on the active surface of the wafer. The back surface of the bumped wafer is adhered to a first mount tape. The wafer is singulated while it is still secured to the first tape to provide a multiplicity of individual dice. The active surfaces of the singulated dice are then adhered to a second tape with the first tape still adhered to the back surfaces of the dice. The first tape may then be removed. In this manner, the back surfaces of the dice may be left exposed and facing upwards with the active surfaces of the dice adhered to the second tape. The described method permits the use of a conventional die attach machine that is not designated for use as a flip-chip die attach machine.

Abstract: A method of packaging integrated circuit dice into exposed die packages is described. The method includes depositing a metallic layer onto the back surface of an integrated circuit wafer such that it covers the back surface. The method additionally includes applying a protective layer over the metallic layer such that the protective layer covers the metallic layer. The method further includes singulating the wafer to produce individual dice. Each die may then be electrically connected to a lead frame. The die and portions of the lead frame may then be encapsulated with a molding compound. The protective layer inhibits the molding compound from contacting the metallic layer on the back surface of the die. The protective layer is then removed from the metallic layer. As a result, an individual IC package is produced that includes a die having a metallic layer exposed on the back surface of the die.

Abstract: A semiconductor package is provided with an internal package formed in the cavity of the external leadless leadframe package (LLP). The internal package is a leadless leadframe package and provides a substrate for mounting one or more die and passive devices to form the external LLP. By arranging the die and passive components on the internal package, higher chip density and a smaller form factor may be achieved.

Abstract: A method of handling an IC wafer that includes a multiplicity of dice is described. Solder bumps are formed on bond pads on the active surface of the wafer. The back surface of the bumped wafer is adhered to a first mount tape. The wafer is singulated while it is still secured to the first tape to provide a multiplicity of individual dice. The active surfaces of the singulated dice are then adhered to a second tape with the first tape still adhered to the back surfaces of the dice. The first tape may then be removed. In this manner, the back surfaces of the dice may be left exposed and facing upwards with the active surfaces of the dice adhered to the second tape. The described method permits the use of a conventional die attach machine that is not designated for use as a flip-chip die attach machine.

Abstract: An integrated circuit package is described that includes a die and a lead frame that includes recessed regions for preventing the undesired spread of solder during reflow. The die includes a plurality of solder bumps formed on its active surface. The lead frame includes a plurality of leads, each having an associated solder pad. Each solder pad is suitably positioned adjacent and electrically contacting an associated solder bump on the die. Each lead also includes a recessed region in a region adjacent to the solder pad. The recessed region serves to isolate the surface of the solder pad from the other surfaces of the lead. In this manner, the solder of the solder bump that contacts the lead is confined to the surface of the associated solder pad.

Abstract: An improved method and apparatus for packaging integrated circuits are described. More particularly, a method and apparatus for use in securing a plurality of integrated circuit dice to a lead frame panel are described. Each integrated circuit die includes an active surface having a multiplicity of solder bumps. The lead frame panel includes an array of device areas, each including a plurality of leads. The method includes positioning a plurality of dice into designated positions on a carrier such that the active surfaces of the dice are facing upwards. The carrier includes a carrier frame including an associated array of carrier device areas. A lead frame panel may be positioned over the carrier such that the solder bumps on the active surfaces of the dice are adjacent and in contact with the associated leads of the associated device areas.

Abstract: A method of fabricating a micro-array IC package is recited. A wafer has a B-stageable adhesive applied, and the wafer is diced. The individual dice are applied to a lead-frame via their adhesive, and wirebonded to associated leads. The lead-frame is then encapsulated, and solder connectors are applied. The lead-frame is then singulated to produce a plurality of lead-frame based micro-array packages. The process thus allows lead-frame based manufacturing methods to be employed in the production of BGA-type packages, allowing such packages to be produced faster and more efficiently.

Abstract: A solder pad configuration for use in an IC package is described. Various embodiments of the invention describe IC packages, lead-frames, or substrate panels configured with generally noncircular solder pads at their bottom surfaces. The noncircular shapes allow for greater surface area than circular solder pads having diameters equal to a major dimension of the noncircular shapes, while maintaining the same metal-to-metal clearance between the pads and adjacent leads. This increased surface area provides for stronger and more reliable solder joints.

Abstract: A die attach region for use in an IC package is described. The die attach region employs a number of posts interconnected with a number of support risers to provide a structure that upholds a semiconductor die while facilitating flow of an encapsulant material underneath the die during encapsulation. The posts and risers can be arranged in a number of configurations that each facilitate flow of encapsulant material. This die attach region can be incorporated into a lead-frame structure or a substrate panel for ease and efficiency of manufacture.