Abstract: A tamper resistant enclosure for an electronic circuit includes an inner copper case, a tamper sensing mesh wrapped around the inner case, an outer copper case enclosing the inner case and the tamper sensing mesh, and a venting device forming a vent channel from inside the inner case to outside the outer case, the vent channel passing between overlapping layers of the tamper sensing mesh and having at least one right angle bend along its length. The venting device consists of two strips of a thin polyamide coverlay material laminated together along their length, and a length of wool yarn sandwiched between the two thin strips and extending from one end of the strips to the other end of the strips to form the vent channel. The length of yarn follows a zig-zag path between the first and second strips, the zig-zag path including at least one right angle bend.

Abstract: A tamper resistant enclosure for an electronic circuit includes an inner copper case, a tamper sensing mesh wrapped around the inner case, an outer copper case enclosing the inner case and the tamper sensing mesh, and a venting device forming a vent channel from inside the inner case to outside the outer case, the vent channel passing between overlapping layers of the tamper sensing mesh and having at least one right angle bend along its length. The venting device includes two strips of a thin polyamide coverlay material laminated together along their length, and a length of wool yarn sandwiched between the two thin strips and extending from one end of the strips to the other end of the strips to form the vent channel. The length of yarn follows a zig-zag path between the first and second strips, the zig-zag path including at least one right angle bend.

Abstract: A method and apparatus for retaining heat at a pin-in-hole rework site on a printed circuit board during solder fountain rework of the board. A preheated heat retention plate is attached to the rework side of the printed circuit board. The heat retention plate covers a substantial portion of the board surface. During rework of the printed circuit board, the heat retention plate minimizes the temperature gradient between the rework site of the printed circuit board and the remainder of the printed circuit board. During the rework, the heat retention plate can be heated by an active heater in order to maintain a constant temperature gradient between the rework site of the board and the remainder of the board. By minimizing the escape of heat from the rework site, the number of solder cycles required to rework the board is decreased, resulting in reduced board rework times and increased board longevity.

Abstract: A method and apparatus for retaining heat at a pin-in-hole rework site on a printed circuit board during solder fountain rework of the board. A preheated heat retention plate is attached to the rework side of the printed circuit board. The heat retention plate covers a substantial portion of the board surface. During rework of the printed circuit board, the heat retention plate minimizes the temperature gradient between the rework site of the printed circuit board and the remainder of the printed circuit board. During the rework, the heat retention plate can be heated by an active heater in order to maintain a constant temperature gradient between the rework site of the board and the remainder of the board. By minimizing the escape of heat from the rework site, the number of solder cycles required to rework the board is decreased, resulting in reduced board rework times and increased board longevity.

Abstract: A method and apparatus for retaining heat at a pin-in-hole rework site on a printed circuit board during solder fountain rework of the board. A preheated heat retention plate is attached to the rework side of the printed circuit board. The heat retention plate covers a substantial portion of the board surface. During rework of the printed circuit board, the heat retention plate minimizes the temperature gradient between the rework site of the printed circuit board and the remainder of the printed circuit board. During the rework, the heat retention plate can be heated by an active heater in order to maintain a constant temperature gradient between the rework site of the board and the remainder of the board. By minimizing the escape of heat from the rework site, the number of solder cycles required to rework the board is decreased, resulting in reduced board rework times and increased board longevity.

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.

Abstract: A electronic apparatus and a process for its manufacture are disclosed. The apparatus includes a planar card for accommodating an electronics module package having protruding solder columns and solder joints to mechanically mount and electrically connect the solder columns of the module to the planar card. The planar card includes a first side and a second side, a plurality of wiring lines forming a wiring pattern, and a plurality of vias extending at least partially through the card. Each of the vias includes at least one recessed area extending from one or both sides of the card. The recessed areas extending to a depth within the planar card sufficient to wick the solder joints, and the each of the recessed areas are shaped to provide surface tension to mechanically retain the solder joints.

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.

Abstract: A method of forming a bond structure for use with integrated circuits and semiconductor electronics and carrier assemblies is disclosed. Metallurgical paste is screen printed through a stencil and the stencil is left in place during the reflow process. The melting point of the bond structure and the metallurgical paste is lower than the melting point of interconnects on the electronic components and less than the decomposition temperature of the carrier assemblies to which the electronic components are bonded.

Abstract: A electronic apparatus and a process for its manufacture are disclosed. The apparatus includes a planar card for accommodating an electronics module package having protruding solder columns and solder joints to mechanically mount and electrically connect the solder columns of the module to the planar card. The planar card includes a first side and a second side, a plurality of wiring lines forming a wiring pattern, and a plurality of vias extending at least partially through the card. Each of the vias includes at least one recessed area extending from one or both sides of the card. The recessed areas extending to a depth within the planar card sufficient to wick the solder joints, and the each of the recessed areas are shaped to provide surface tension to mechanically retain the solder joints.

Abstract: A method of forming a bond structure for use with integrated circuits and semiconductor electronics and carrier assemblies is disclosed. Metallurgical paste is screen printed through a stencil and the stencil is left in place during the reflow process. The melting point of the bond structure and the metallurgical paste is lower than the melting point of interconnects on the electronic components and less than the decomposition temperature of the carrier assemblies to which the electronic components are bonded.

Abstract: The present invention may be characterized as an improved integrated circuit die testing system which includes a number of components which cooperate together. An integrated circuit carrier is provided for holding the integrated circuit die. Attached to the integrated circuit carrier is a chip site. Proximate to this chip site exists a plurality of contact pads. These contact pads are electrically coupled to a plurality of test points. Also provided is an integrated circuit die. Finally, a pattern of electrically conductive paste is provided. This electrically conductive paste electrically couples the integrated circuit die and the contact pads thereby allowing the integrated circuit die to be tested from the test points.