The effect of local fluence on the micropatterning of poly(ethylene terephthalate) foils through proton beam writing

The potentialities of ultrasound as an alternative to chemical etching for proton beam writing micropatterning

“…For other polymers such as polyethylene terephthalate (PET, Mylar ® ), an etching procedure consisting of a 6 M NaOH solution in a thermal bath with magnetic stirring has been used successfully for the removal of the damaged structures. 6 In the present study, two similar routes employing ultrasonic waves were followed as post-irradiation treatment. One of them made use of a 6 M NaOH solution as the wave propagating medium, while another one employed just distilled water.…”

“…Since the beam spot size on the target is 3.5 Â 3.5 μm 2 , a considerable overlap of the beam takes place when the beam moves from one pixel to the next one, thus giving rise to a nonuniform irradiation of the polymer as discussed elsewhere. 6 Commercial polytetrafluoroethylene (PTFE) foils of about 1 cm 2 area and (2.0 ± 0.4) mm thick were irradiated with 2.2 MeV protons with an average current of 50 pA. According to simulations carried out with the SRIM/TRIM software package, 21 such protons have a range of about 53 μm in PTFE.…”

“…In the present case, the scan size (256 × 256 μm 2 ) matches the number of pixels programmed in the scanning system (256 × 256), thus leading to a pixel size of 1 × 1 μm 2 . Since the beam spot size on the target is 3.5 × 3.5 μm 2 , a considerable overlap of the beam takes place when the beam moves from one pixel to the next one, thus giving rise to a nonuniform irradiation of the polymer as discussed elsewhere 6 …”

“…2,4 Other factors including the ion fluence, the etchant or developer and the etching time play an important role as well. 5,6 Polytetrafluoroethylene (PTFE) is a fluorinated polymer widely used by the industry for several applications. 7 This polymer, known as teflon ® , exhibits a high degree of inertness as it is remarkably resistant to chemical agents and is not soluble in most solvents.…”

“…The patterning of ultimate high‐quality structures depends on several factors including focusing ion system, beam fluence, and the choice of an appropriate material 2,4 . Other factors including the ion fluence, the etchant or developer and the etching time play an important role as well 5,6 …”