Abstract:
A paste is described for capping electrodes with an oxide free metal layer incorporating a solvent, an unzippable polymer and particles. The electrode could be an interconnect such as a C4 bump. A method for forming a coating and for testing integrated circuit chips is also described. The invention overcomes the problem of interconnecting Pb containing electrodes that are covered with an insulating oxide on integrated circuit chips by coating the Pb containing electrode with Au to provide an oxide free surface for testing and interconnection.
Abstract:
A method of forming interconnects on an electronic device that can be bonded to another electronic device at a low processing temperature can be carried out by depositing a first interconnect material on the electronic device forming protrusions and then depositing a second interconnect material to at least partially cover the protrusions, wherein the second interconnect material has a lower flow temperature than the first interconnect material. The method is carried out by flowing a molten solder into a mold having microcavities to fill the cavities and then allowed to solidify. The mold is then aligned with a silicon wafer containing chips deposited with high melting temperatures solder bumps such that each microcavity of the mold is aligned with each high melting temperature solder bump on the chip. The aligned mold/wafer assembly is then passed through a reflow furnace to effect the transfer of the low melting temperature solder in the mold cavities onto the tip of the high melting temperature solder bumps on the wafer. A dual metallurgical composition bump is thereby formed by the two different solder alloys.
Abstract:
Fine pitch area array packaging is achieved using a via-in-pad design within the area array attach portion of a printed circuit board (PCB). The limitation of the design is the wicking action, whereby solder applied to the capture pad contact surface is depleted by capillary action into the via hole when reflowed, causing insufficient solder to be present at the contact surface to effect reliable and repeatable electrical connections. In one implementation, an initial application of solder is applied to plug the via hole with a material having a higher final melting temperature than eutectic solder, thereby providing a stable plug. This plug is formed by the initial solder application that may be either a eutectic solder containing a third metal that forms intermetallic compounds, when reflowed, that elevate the liquidus temperature or a solder having a different formulation with an inherent higher melting temperature. An alternative implementation is to plate the via hole with a material, such as nickel, which prevents eutectic solder, applied to the via capture pad contact surface, from wetting the hole surface and being drawn away from the contact surface by capillary action. Thus, the solder, applied to the via capture pad and used to establish an electrical connection is not depleted.
Abstract:
The specification describes techniques for attaching double sided circuit boards having plated through holes to interconnection substrates using solder bump arrays. The through holes are filled with a high melting point solder which allows solder bumps to be located directly on the through hole thus saving board area and reducing the interconnection length.
Abstract:
Solder interconnection for forming connections between an integrated semiconductor device and a carrier substrate is provided. Located on the carrier substrate are electrodes and located between the electrodes and integrated semiconductor device are solder connections that have a relatively low melting point such that when the device is in operation, the solder connection will liquify thereby permitting expansion compensation between the substrate and semiconductor device.
Abstract:
The present invention provides multi-layer multi-chip circuit board comprising at least two ATAB carriers having chips thereon, stacked upon each other in a pyramid configuration and attached to a substrate, thus reducing the required area on the substrate for mounting components to form a circuit board.
Abstract:
In aspect, the present invention is directed to a method of modifying a circuit board having at least one Ball Grid Array (BGA). The method includes removing the via portion of the BGA pad from the circuit board to sever the connection between the via and the circuit, attaching the pad connector to the circuit board, and connecting the pad connector to the circuit of the circuit board.
Abstract:
Solder interconnection for forming connections between an integrated semiconductor device and a carrier substrate is provided. Located on the carrier substrate are electrodes and located between the electrodes and integrated semiconductor device are solder connections that have a relatively low melting point such that when the device is in operation, the solder connection will liquify thereby permitting expansion compensation between the substrate and semiconductor device.
Abstract:
A packing structure for a surface mounting type semiconductor package, wherein at least one semiconductor chips are mounted on a die pad. A conductive pattern is formed on a printed circuit board which is located beneath an exposed side of a die pad of the package. A nonconductive thin film or a conductive layer is formed between the conductive pattern and the die pad. The conductive pattern is electrically connected to the die pad so that there is generated the package voltage difference therebetween, thereby reducing the electric noise of the package and facilitating high speed operation of the package without reducing a mounting density.
Abstract:
A hybrid integrated circuit device is equipped with a shield structure, and the shield structure has a peripheral shield frame soldered to a peripheral shield member of a mother board so as to encircle electrodes of the hybrid integrated circuit device therewith, thereby decreasing noise due to the electromagnetic wave generated by the electrodes.