Integrated Circuit Pointed Elements via Low-Thermal-Budget Etching

The patent replaces the thermal oxidation process with a chemical etching process. Instead of using high-temperature oxidation to form tips on polysilicon, the invention uses selective chemical etching of a sacrificial material (such as BARC layers, resins, or carbonaceous layers) to create craters that form tips. This substitution eliminates the need for significant thermal budget while enabling tip formation on various materials including metals and polysilicon in both FEOL and BEOL regions.

The patent changes the fundamental process parameter from thermal (oxidation temperature) to chemical (etch selectivity). By using etchants with different selectivities to etch the sacrificial material at different rates, the process controls tip dimensions through chemical parameters rather than thermal parameters. This allows tip formation at lower temperatures while maintaining versatility across different materials and circuit regions.

The patent creates a universal tip formation process that can be applied across multiple contexts: FEOL and BEOL regions, different materials (polysilicon, metals, etc.), and various circuit functions. The sacrificial material layer approach serves multiple purposes: it protects underlying structures during etching, enables selective removal to create craters, and can be removed afterward to release the pointed region. This multi-functional approach simplifies manufacturing by providing a single process paradigm for diverse applications.

The sacrificial material (BARC layers, resins, or carbonaceous layers) acts as an intermediary between the etching process and the final tip structure. This intermediary layer is selectively etched to create craters, which then define the tip geometry. The sacrificial material protects the underlying substrate during selective etching and can be completely removed after crater formation, leaving the desired pointed structure without requiring direct etching of the final material.