An accurate assessment of the bonding temperature values in the adhesive layer during Anisotropic Conductive Film bonding is complicated by several factors related to small dimensions, large temperature gradients, and inherent-thermal perturbations caused by the measurement technique. Thermal modeling simulations were used to characterize the temperature values and evaluate their influences on the dynamic temperature variation through the bonding process used for thin electronic devices. These simulations reveal the degree of temperature gradient through the electronic assembly layers and within the adhesive, the effects of design changes, and the significance of equipment parameters on the temperatures reached during bonding. The simulations show that the adhesive temperature can vary by more than 30 degrees C across the characteristic sizes both of the total bond area and along or between the individual circuit traces. Also, the heat transfer through the layers showed changes due to the device design and bonding equipment base material choice of 40 to 80 degrees C in some cases. Therefore, thermocouples in the adhesive used to measure the temperature must use very fine wire size and require meticulous precision in positioning to insure accuracy and reproducibility in the adhesive bonding conditions to enable the highest yield and reliability. (c) Koninklijke Brill NV, Leiden, 2008