Figure S1. Detailed explanation of microfabrication step of fully
integrated NIR-LFC. a) The wafer-level microfabrication of iMLA-AFF
involves a thin Cr lift-off, and plasma enhanced chemical vapor
deposition (PECVD) of SiO2, and a thick Cr lift-off (6
nm Cr – 135 nm SiO2 – 130 nm Cr), photolithographic
patterning of DNR photoresist (DNR L300-D1, Dong-jin Semichem, Co., Ltd,
Korea), and thermal reflow. Note that a DNR photoresist exhibits both UV
curable (Negative photoresist) and thermoplastic characteristic,
suitable for metal lift-off as well as microlens formation. The
hydrophobic coating of fluorocarbon
(C4F8) effectively prevents the lateral
expansion of microlenses on a metal surface during thermal reflow.
iMLA-AFF are inversely bonded to an image sensor with a 60 μm gap spacer
and packaged to a compact objective lens by using a UV curable adhesive.
The NIR-LFC is fully assembled by combining a 8.5 mm × 4.7 mm printed
circuit board with two VCSEL sources and VCSEL housing. b) A scanning
electron microscope (SEM) of hexagonally arranged iMLA-AFF with 30 μm in
microlens diameter and 3 μm in microlens gap. c) A photograph of fully
packaged NIR-LFC. The camera module is connected to flexible extension
cable and delivers raw image to Raspberry Pi 4(B). The total physical
dimension of camera module is 8.5 mm × 14.0 mm × 5.6 mm.