Thousands Of Wires Research Articles

Multipurpose Wire Bonding – Bumps, Wires, Combination Interconnects, and Operation Efficiency

Today's multipurpose wire bonding machines are required to deliver a combination of wires, bumps, and specialty interconnects for RF, automotive, and optical markets with odd-form factor parts. These market production requirements are generally lower volume with a higher mix of products compared to typical high-volume semiconductor packaging of memory and logic. These markets also require multipurpose wire bonders to accommodate large work area, deep access, and a complex mix of bond surfaces, wire shapes, and bumps. The number of components in a package can vary from one with a few wires up to hundreds of components with thousands of wires. Programming methods, process development, traceability, and rework are different for customers using this class of bonder. A survey of customer application cases shows the range of capabilities available to packaging engineers. The four primary cases presented highlight the range of applications that can be handled for odd-form factor packages and specific areas of focus to maximize productivity for these classes of products.Case 1: Ball Bump Size and Shape Examples: acheiving 119μm down to 44μm bonded ball diameters and range of shapes.Case 2: Ambient Wire Bonding to a 6″ Tall Package: demonstrating allowable bonding volume and tooling flexibility plus the ability to bond Au with substrates at ambient temperature.Case 3: Batch Load Tray (Mechanical and Vacuum Clamping): allowing quick change over for radically different sized packages.Case 4: Complex High Part Count Packages: supporting alternate parts and alternate bonding wires, stand-off stitch, and security bonds require special features for programming and navigation methods to allow easy creation and navigation of complex programs for maximum productivity. Breakdown of timing and efficiency is provided showing programming efficiencies of 2X or better. These cases will help packaging engineers extrapolate to their own cases and show how a multipurpose automatic wire bonder can be an effective way of automating or semi automating these manually or automatically presented packages for higher throughput, higher quality and consistency, and less labor usage for lower cost.

Conductivity enhancement of silver filled polymer composites through electric field alignment

We show how an alternating electric field can be used to align silver micron or sub-micron sized particles into microscopic wires in diverse polymer matrices based on the dielectrophoretic effect. The electric field is set by an electrode pair and the wires form conductive pathways through the matrix, bridging these electrodes electrically. The matrix is cured after alignment, locking wires in permanent pathways within the polymer. The wires are then characterized by ac impedance spectroscopy. The alignment can take place either in-plane or out-of-plane, and yields a directional conductivity in the alignment direction parallel to the electric field lines. The samples can be centimeters wide containing thousands of wires in parallel, but even an individual wire can be grown and controlled. The initial mixture contains less than 1 vol.% of silver and is an electrical insulator. The bulk conductivity enhancement, due to the alignment, may be 5 orders of magnitude, typically from 1 � 10 � 5 S/m to 1 S/m as the particle alignment converts the sample conductivity from polymer dominated to silver dominated. For the aligned isolated silver wires, the jump in conductivity, confined to the volume filled by the wire can be seen to be as high as 9–10 orders of magnitude, resulting in conductivities as high as 1 � 10 5 S/m, thus approaching those

Partition-based algorithm for power grid design using locality

This paper presents an efficient heuristic algorithm, which employs successive partitioning and grid-refinement scheme, for designing the power distribution network of a chip. In an iterative procedure, the chip area is recursively bipartitioned, and the wire pitches and the wire widths of the power grid in the partitions are repeatedly adjusted to meet the voltage drop and current-density specifications. By using the macromodels of the power grid constructed in the previous levels of partitioning, the scheme ensures that a small global power grid system is simulated in each iteration. The idea is based on the notion that due to the locality properties of the power grid, the effects of distant nodes and sources can be modeled more coarsely than the nearby elements, and include practical methods that enhance the convergence of the iterative conjugate-gradient-based solution engine that is used in each step. Finally, a postprocessing step at the end of the optimization is employed to maximize the alignment of wires in adjacent partitions. The effectiveness of the scheme is demonstrated by designing various power grids with real circuit parameters and realistic input current values. The proposed algorithm is able to design power grids comprising thousands of wires and more than a million electrical nodes in about 6 to 14 min. When compared to a multigrid-based power grid design scheme, it is found to save about 5% to 10% of wire area, and on an average is 12% faster.

Electronics circuits associated to multiwire proportional chambers

This paper describes our acquisition system for information delivered by multiwire proportional chamber allowing to operate with chamber involving thousands of wires like with several chambers or detectors.