| 摘要 |
An integrated circuit solder bumping system provides a substrate and forms a redistribution layer on the substrate. An insulation layer is formed on the redistribution layer. The insulation layer has a plurality of openings therethrough. A first UBM layer of titanium is deposited on the insulation layer and in the openings therethrough. A second UBM layer of chromium/copper alloy is deposited on the first UBM layer. A third UBM layer of copper is deposited on the second UBM layer. UBM pads of at least two different sizes are formed from the UBM layers. Solder paste is printed over at least some of the UBM pads. The solder paste is reflowed to form at least smaller solder bumps on at least some of the UBM pads. Bigger solder bumps are formed on at least some of the UBM pads.
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