QFN引线框架基岛面的分层研究

发布时间：2018-06-04 09:33

本文选题：QFN + 分层　；参考：《苏州大学》2015年硕士论文

【摘要】：封装是实现芯片工作性能的最后一环。对QFN(Qual Flat Non Lead,四方扁平无引脚封装)而言,解决封装中所产生的分层问题对延续产品寿命具有重要意义。本论文侧重于QFN封装中发生概率最高、最难以解决的基岛面分层现象,结合分层面不同微观表象,针对性设计多达32组DOE(Design of Experiment,实验设计)实验,经验证,得出如下结果:(1)使用贴片胶代替贴片膜、在基岛上表面增加凹槽设计、对框架上表面进行棕化处理,能不同程度减小或消除框架基岛上表面环芯片区的分层现象。对应的考量参数分别是:弹性模量与热膨胀系数,结合面积,黏贴强度。(2)减小基岛背部半蚀刻面积、对框架下表面进行棕化处理,能不同程度减小和消除基岛下表面区半蚀刻区的分层现象。对应的考量参数分别是:填充间隙,黏贴强度。(3)改变框架贴胶带模式、减小塑封树脂的热膨胀系数,均不能使框架基岛环芯片面的分层结果发生任何变化。(4)使用贴片胶代替贴片膜的局限性在于芯片堆叠层数;在基岛上表面增加凹槽设计的局限性在于芯片大小;减小基岛背部半蚀刻设计的局限性在于客户端焊盘设计。而棕化处理没有任何局限性。综上结论有,材料属性(弹性模量、热膨胀系数),框架设计(结合面积、填充间隙),棕化处理(黏贴强度)是解决分层的三个重要方向;针对不同分层现象、不同封装结构要求和不同客户质量要求,三者之间需要合理调配。
[Abstract]:Encapsulation is the last step to realize the working performance of the chip. For QFN(Qual Flat Non Lead, quadrilateral flat pin-less packaging, it is very important to solve the delamination problem in packaging. This paper focuses on the highest probability of occurrence and the most difficult to solve the phenomenon of basal island stratification in QFN packaging. In combination with different microcosmic images of different layers, 32 groups of DOE(Design of experimental design experiments are designed and verified. The results are as follows: (1) using patch glue instead of patch film, adding grooves to the surface of the base island and browning the upper surface of the frame can reduce or eliminate the delamination of the chip region on the surface of the frame island in varying degrees. The corresponding parameters are as follows: elastic modulus and thermal expansion coefficient, bonding area, adhesive strength. It can reduce and eliminate the delamination of the semi-etched area on the subsurface of the basal island to varying degrees. The corresponding parameters are as follows: filling gap, adhesive strength. 3) changing the pattern of frame adhesive tape and reducing the coefficient of thermal expansion of plastic seal resin. The limitation of using patch glue instead of patch film lies in the number of stacking layers of chip, the limitation of adding groove to the surface of base island is chip size. The limitation of base island back half etching design is client pad design. However, the browning process has no limitations. It is concluded that the properties of materials (modulus of elasticity, coefficient of thermal expansion), frame design (bonding area, filling gap), brown treatment (adhesive strength) are three important directions to solve the problem of delamination. Different packaging structure requirements and different customer quality requirements, the three need to be reasonably deployed.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN405

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