Positioning errors in transfer printing-based microassembly

Abstract

Positioning errors in transfer printing that utilizes an elastomeric stamp to transfer microobjects (also termed “inks”) is studied here to determine the limit of positioning resolution of transfer printing-based microassembly. The angular misalignment between a stamp and a receiving substrate emerges as a crucial source of positioning errors because it is hard to eliminate completely based on capabilities of a transfer printing setup. In this paper, the positioning error induced by angular misalignment is quantitatively studied using a numerical approach and qualitatively investigated by experiments. Elastomeric stamps with two standard designs, ie flat stamp and microtip stamp, are both examined in the numerical study, and the results predict that higher accuracy can be achieved with a microtip stamp. Nevertheless, both designs show the potential to achieve submicron positioning resolution in well-controlled transfer printing conditions (less than 1° of angular misalignment). Analytical models are built based on pin joint mechanism and beam theory to compare with the numerical models. Finally, transfer printing experiments are carried out with prescribed angular misalignment in order to verify the proposed error generation mechanism. This work serves as the first attempt to systematically study positioning errors occurring during transfer printing-based microassembly.