Ordered topographically patterned silicon by insect-inspired capillary submicron stamping

TL;DR

This paper presents a novel insect-inspired capillary stamping technique combined with chemical etching to produce ordered topographically patterned silicon with potential applications in labeling and security features.

Contribution

It introduces a new capillary submicron stamping method inspired by insect feet, enabling high-throughput, ordered patterning of silicon surfaces with versatile applications.

Findings

Ordered arrays of AgNO3 dots on silicon achieved by manual stamping.

Surface-limited MACE produced macroporous silicon or silicon pillar arrays.

Polymer patterns conformally cover the patterned silicon surfaces.

Abstract

Insect-inspired capillary submicron stamping and subsequent surface-limited metal-assisted chemical etching (MACE) with ammonium bifluoride as HF source is employed for high-throughput production of ordered topographically patterned silicon (tpSi). Insect feet often possess hairy contact elements through which adhesive secretion is deployed. Thus, arrays of adhesive secretion drops remain as footprints on contact surfaces. Stamps for insect-inspired capillary submicron stamping having surfaces topographically patterned with contact elements mimic the functional principles of such insect feet. They contain spongy continuous nanopore networks penetrating the entire stamps. Any ink (organic, aqueous) may be supplied from the backside of the nanoporous stamps to the contact elements. We generated ordered arrays of AgNO3 dots extending mm^2 on Si by manual stamping with cycle times of a few seconds under ambient conditions; at higher load ordered holey AgNO3 films were obtained. Surface-limited MACE correspondingly yielded either macroporous tpSi or Si pillar arrays. Inkjet printing of polymer solutions onto tpSi yielded patterns of polymer blots conformally covering the tpSi. Such blot patterns could potentially represent a starting point for the development of persistent and scratch-resistant identity labels or QR codes on silicon surfaces.