INDEX underfill

Guidelines for Selection and Apphcation of Underfill Materials for Flip-Chip and Other Micropackages, JEDEC J-STD-030 Dec. 2000. http //standards.gov/sibr/index. Accessed 2.09.10. 

A property related to viscosity is the thixotropic index, ameasure of the dependence ofviscosify on shear-rate. The thixotropic index (TI) is the ratio of viscosities measured at speeds that have aratio of 1 10 rpm, for example, at 2 rpm and 20 rpm. For non-Newtonian materials used in automated dispensing, shear thinning is apparent from TI values of 2-6. In general, capillary-flow underfills have thixotropic indices of 1, or close to 1. 

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