A Si stencil mask for deep X-ray lithography fabricated by MEMS technology

We succeeded in making a Si stencil mask for deep X-ray lithography (DXL) by using MEMS fabrication technologies. In order to make this mask, a 200 μm thick Si wafer was etched through its entire thickness where the remaining silicon served as the absorber for the mask. The minimum line width on the mask was 20 μm. DXL experiments were executed by using this Si stencil mask on the beamline BL2 at the NewSUBARU SR facility of the Laboratory of Advanced Science and Technology for Industry, University of Hyogo. In our experiment we succeeded in the X-ray exposure of PMMA sheets through their entire thicknesses of 0.5 and 1 mm. This means a success in line/space patterning with 20 μm line width that can lead to the fabrication of PMMA structure of maximum aspect ratio of 50. Moreover, the sticking was prevented by substituting water with hydrofluoroether employed for after-develop wash operation This Si stencil mask enabled a transcript of more precise pattern using the beamline BL2 at the NewSUBARU SR facility as compared with results from a stainless stencil mask and an Au/polyimide mask.