Scalable SiO ₂ /Epoxy Dielectric Films for High‐Yield and Fine‐Line Substrate Fabrication via Copper Tooth Transfer Printing

Reducing the width and space of copper lines on advanced organic packaging substrates is a direct way to increase the circuit density for multifunctional applications. Herein, a new process called copper tooth transfer printing (CTTP) is reported that can manufacture substrates with fine line width and space using traditional low‐cost printed circuit board manufacture equipment. A scalable SiO ₂ /epoxy composite film is fabricated by die coating and performed high performance for realizing the CTTP process. Two types of copper foils of high temperature elongation electrodeposited (HTE) and reverse treat foil (RTF) with different surface roughness are used to evaluate the CTTP process. The pit structure observed on the composite film surface after CTTP process offers rivet point for the forming of copper seed layer. High values of peel strength about 0.48 and 0.33 N mm ⁻¹ are achieved by using HTE and RTF copper foils, respectively. Importantly, a high automated optical inspection yield rate of the lines above 96% on both side of the substrate with line width and space of 40/20 μm is achieved by using the RTF copper foil owing to the less copper tumor formed. The CTTP process will be a promising route for fabricating advanced high‐density packaging substrates.