Measurement of thermally induced strains on flip chip and chip scale packages
Measurement of thermally induced strains on flip chip and chip scale packages
复制标题
倒装芯片和芯片级封装上热致应变的测量
DOI：
10.1109/itherm.2000.866196
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
B. Michel
中科院分区：
文献类型：
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作者：
D. Vogel;E. Kaulfersch;J. Simon;R. Kuhnert;A. Schubert;B. Michel
作者开发和利用microDAC变形测量技术，以确定热应力，横截面FC和CSP试样的应变场。该方法允许解析微小结构（例如焊料互连或导电粘合剂层）内部的应变场。它是基于从不同的对象负载状态获得的数字化显微照片的比较。光学、SEM和激光扫描显微镜用于图像捕获。本文给出了不同倒装芯片配置和芯片级封装类型（例如，在大多数倒装芯片情况下，通过底部填充几乎完全抑制了向外凸起的整体剪切。此外，在用作板材料的有机层压板中，玻璃织物的局部外观会强烈影响凸块变形。对芯片级封装可靠性的主要要求是避免过大的热焊球应变，这会导致材料疲劳。具有刚性和柔性内插器的不同封装以不同的方式解决应力补偿问题。第一次尝试是比较他们中的一些实验应变和翘曲测量的基础上。
The authors developed and made use of the microDAC deformation measurement technique to determine strain fields on thermally stressed, cross sectioned FC and CSP specimens. The method allows one to resolve strain fields inside tiny structures like e.g. solder interconnects or conductive adhesive layers. It is based on comparison of digitized micrographs obtained from different object load states. Optical, SEM and laser scanning microscopy are applied for image capture. The paper presents results of strain analysis in interconnects of different flip chip configurations and chip scale package types e.g., global shear of outward bumps is almost completely suppressed in most flip chip cases by underfilling. Furthermore, bump deformation can be strongly influenced by the local appearance of glass fabrics in organic laminates used as board materials. A main demand on chip scale package reliability is the avoidance of too large thermal solder ball strains, which lead to material fatigue. Different packages with rigid and flex interposers tackle the stress compensation problem in a different way. A first attempt is made to compare some of them based on experimental strain and warpage measurements.