In-situ resist temperature monitor during hot embossing lithography by fluorescence probe technique

method usually based on thermocouple2 or IR thermal detector, it can not easily in-situ measure the temperature of resist film as thin as sub-micrometer. To measure the resist film temperature during the processes, we develop a fluorescence probe method to record the highest temperature in resist deformation processes. Florescence temperature measurement is a rapid, high precision and high accuracy meth~d.~ The thermal florescence microscopy setup was shown in figure 1. Herein, fluorescence (FL) dye, rhodamine B, as an irreversible temperature indicator, mixed with resist was heated in different temperature from room temperature to 250 degree C. Figure 2 depicts the fluorescence emission intensity (-59Onm) linear decay from 1 to 0.35 measured by PMT as temperature increased. To precision calibrate the temperature measurement for a long heating time, we continuously heat the mixed resist up to 9 hrs. Figure 3 shows that it still had good linear relationship between FL intensity and heating time. It also indicates that it is a robust method for long time temperature measurement, Because of the dye linear decomposition with temperature increased, figure 4 reflects that UV absorption, at 550nm, decrease from low to high temperature. The figure 5 shows that the 6-inch wafer temperature measurement after hot embossing processes, and find out the temperature variation is about 12 degree C between center and periphery may caused by various heating condition. The temperature precision can achieve to iO.01 degree C at the same imprint temperature between different batch .The smallest measurement area can down to sub-micrometer area based on the resolution of optical microscopy and sensitive detector. In the future, the method is not only applied to the in-situ temperature variation inspection on whole wafer but help to study the resist deformation processes during embossing processes. 1.C. Perret, C Gourgon, G, Micouin, J. P. Grolier Jpn. J. Appl. Phys.Part.1, 41, 4203,