CD control in UV nanoimprint by altering the ratio of two types of condensable gases used for bubble elimination

Time 2018-11-09 10:40~11:05 Place Rm.600A
Code No. MD-O09 Session Chair
Name Dr. Hiroshi Hiroshima
Affiliation Research Center for Ubiquitous MEMS and Micro Engineering
Title CD control in UV nanoimprint by altering the ratio of two types of condensable gases used for bubble elimination
Contents
UV nanoimprint in air inevitably causes air bubble trapping. However, the problem can be solved by using condensable gases (ex. Pentafluoropropane (PFP)) as the nanoimprint environment. When UV nanoimprint is carried out in PFP, the PFP is also trapped in mold recesses and the volume of the trapped PFP decreases with the increasing of the imprinting pressure. On the other hand, the pressure of the trapped PFP increases with the decreasing of the trapped PFP volume, however, it cannot exceed the saturated vapor pressure of PFP (i.e. 0.15 MPa). Therefore, by applying the imprinting pressure larger than the value, PFP is completely liquefied and bubble free UV nanoimprint is realized. It was found that PFP has some side effects. A good point is release force reduction and bad points are rough surface and large resin shrinkage. It was also found that these side effects are due to absorption of the condensable gas into UV curable resin and the amount of absorbed gas is strongly dependent on the combination of the condensable gas and UV curable resin. This implies that we can control the side effects. A natural approach is to mitigate the bad points, but, it is also interesting to actively utilize the characteristics seemingly bad. In the presentation, we will present UV nanoimprint using condensable gases and demonstrate that the pattern widths are controllable by altering the ratio of two types of condensable gases using an identical mold.