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Nimbus :
Flip Chip Advanced Packaging :
Stratus
Electro-deposition :
Cirrus :
ECR :
Publications Library
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Nimbus :
Flip Chip Advanced Packaging :
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Fig 1.) The Nimbus deposits the metal layer between the aluminum pad of an IC for direct soldering of a chip to a substrate.  Fig 2.) IC with leads distributed and solder ball attached. 
Fig 3.)The resulting package size achieved with flip chip technology. The top figure illustrates surface mount technology (SMT) which is now in wide use. The lower figure illustrates the same IC packaged with flip chip technology. Courtesy of TechLead Corporation.  Fig 4.) The Cirrus 80 offers faster, cooler processing to clean every die, every time. |
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Flip chip process technology enables extremely compact, high performance electronic systems which are in increasing demand for portable electronics or systems embedded in other products. The Nimbus and Cirrus 80 systems and their core technologies focus on flip chip advanced packaging, including wafer bumping, wafer cleaning, photoresist strip, and related technologies.
Flip Chip
Connections are made to a ceramic or other insulating substrate, which incorporates a printed circuit that connects multiple chips together or provides for the integration with external circuit elements such as antennae, keyboards, transmission cables, or displays. The drawing illustrates the metal layers of chromium, copper, and gold which can be deposited with the Nimbus UBM process on the metal pad or contact area of an IC. This metal layer allows for direct attachment of a solder ball for connection to a circuit board substrate. The switch from surface mount technology to flip chip packaging permits increased packaging density, up to a factor of ten times. This increased density allows for a greater number of chips to be placed in future hand-held devices, as well as leading to improved performance of all high processing rate electronic products, such as microprocessors, workstations, and high speed telecommunication products. Flip chip packaging eliminates the need for wire bonding by placing the contact points of the chip in direct contact with the packaging substrate and requiring the stringent control of the placement of the chip on the substrate. This method of advanced packaging of ICs offers advantages in size, signal speed, cost, and reliability. The high throughput and low cost of the Nimbus make it an ideal tool for this process. Another critical step in processing wafers for packaging applications is the cleaning of the aluminum pad prior to die attach, wire bonding, or encapsulation. The Cirrus 80 system, with its low pressure operation, is ideally suited to effective cleaning of deep, confined spaces, such as those between substrates mounted in magazines.
“A Sputtered Nickel Under Bump Metallurgy Structure for Lead-free Solder for Use in Flip Chip Packaging,” by K. O’Donnell, J. Kostetsky, and R. DeVito, NEXX Systems; and V. Bellido-Gonzalez, S. Powell, and D. Monaghan, Gencoa, presented at the Flip Chip conference 2003 [728K]
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Following are application notes of interest: