Directly Photopatternable Polythiophene as Dual-Tone Photoresist

Abstract

We report a directly photopatternable polythiophene derivative PT o NB with o-nitrobenzyl (oNB)-functionalized side chains. PT o NB has unique phototunable solubilities programmed through three stages: (i) organic-soluble/aqueous-insoluble, (ii) organic-insoluble/aqueous-insoluble, and (iii) organic-insoluble/aqueous soluble. The capability to control conjugated polymer solubility with spatiotemporal precision and orthogonal developer solvents through three stages allows for direct patterning of this conjugated polymer and provides flexibility to choose between positive and negative tone photolithography. This approach to photomodulate solubility also enables all-solution processing of multilayer stacked conjugated polymer films; we demonstrate here direct two-layer photopatterning with this novel conjugated polymer photoresist.

Dual-tone Application of a Tin-Oxo Cage Photoresist Under E-beam and EUV Exposure

“…Dual-tone properties of photoresists have been reported in recent years [11][12][13][14][15][16]. Switching between positive and negative tone patterns is usually achieved by changing the developer [3,11,13]. In the present work, a dual-tone patterning is realized by performing the PEB step at an elevated temperature (150 o C for 2 min) after EUV or e-beam exposure and before development (2:1 IPA/H 2 O for 30 s).…”

Universal three-dimensional crosslinker for all-photopatterned electronics

“…However, fabrication of these devices entirely through a series of solution processes remains highly challenging, as they comprise a stack of fully patterned electronic components, such as electrode layers, charge transporting interlayers, active channel layers, and insulating layers. While various processing methods have been developed for patterning and stacking each of these electronic component layers separately [16][17][18] , employing multiple techniques/equipment tailored to form respective layers for fabricating devices entirely through a series of solution processes is nontrivial and cost-ineffective. Moreover, new issues arise when a solution-processed layer is exposed to chemicals during the subsequent processing steps.…”

“…For instance, conventional photolithography requires multiple steps that involve exposure of a given electronic layer to various chemicals, such as photoresist, developer, and etchant 7,16,19 . This means that finding an appropriate orthogonal chemicals that do not damage the underlying electronic layer is critical for successful pattern formation by photolithography 17,20 . The wider spread of this technique for patterning layers of solution-processable materials is thus limited.…”

Advances in the Synthesis of π‐Conjugated Polymers by Photopolymerization

“…Exposing monomer thin films to visible light with a laser-cut mask yielded patterned films with high resolution (Figure 6). As direct photopatterning has proved to be a challenging goal for the conjugated polymer community, [49][50][51][52] this method may inspire future work in the use of photopolymerization to create CP-based pixel arrays or circuit elements.…”