| 摘要 |
A no-flow underfill material and process for underfilling a flip chip component. The underfill material comprises at least three polymer layers. A first of the layers overlies terminals of a substrate to which the component is to be mounted. The first and second layers are substantially free of fillers, while the third layer contains a filler material to reduce its CTE. The underfill process entails placing the component so that solder terminals thereof penetrate the first, second and third layers and contact the terminals on the substrate. Because only the third layer contains filler material, penetration of the underfill material by the solder terminals is substantially unimpeded. The solder terminals are then reflowed, during which the filler material migrates into the unfilled first layer and the first, second and third layers consolidate and cure to form a single underfill layer.
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