Evaluating the Performance of c-C4F8, c-C5F8, and C4F6 for Critical Dimension Dielectric Etching

Introduction: One of the many challenges IC manufacturing faces with the advancement of technology nodes is reactive ion etching [RIE] of dielectric materials to produce smaller feature with higher aspect ratios. Compounding the difficulty is the introduction of 193 nm photoresist materials, whose chemical composition makes them less resistant to RIE and their depth of focus requires the use of thinner films to pattern during lithography. Another trend that is also beginning to factor in is the use of lower k dielectric materials. Many of these materials are carbon doped silicon oxide. The challenge they presents is a possible reduction in etch selectivity between the resist and dielectric being etched, because of organic forms of carbon being included in the structure of the material.