Exploration of Boundary Conditions for Capacitor Etching Methods Under the Background of Characteristic Process

In analog IC circuits, capacitors are important passive components and mainly have functions such as bypassing, decoupling, filtering, and energy storage. Based on the 12-inch wafer manufacturing platform, this paper conducts parallel technical research aiming at the difficulties that appear in the etching process of capacitor devices, and explores the boundary conditions of capacitor etching methods. Through controlled experiments and combining characterization methods such as microscopic morphology analysis, element detection, and electrical performance detection, this research shows that innovative etching methods can improve process precision, expand the process window, and enhance the reliability of capacitor devices. The feasibility of using mild etching modification to form spacer morphology to protect the weak positions of Al MIM was studied; the good removal effect of the two-step flushing method on Al MIM polymer was analyzed; it was verified that the gas combination of Cl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/CH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> can better protect the dielectric layer and expand the process window; and by using Cl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/BCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>/AR combined with a specific radio frequency power, stable etching of ultra-thin high-k dielectric was achieved, and the capacitance density can reach 595 fF/μm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>.