Focused Ion Beam has proven to create refractive solid immersion lenses in silicon that can significantly improve the resolution of optical backside analysis tools. The SIL performance in our previous works has been limited though, mostly due to a pure sputtering process. This problem is addressed by developing a chemistry-assisted FIB process, offering the ability to create larger SIL shapes. A 50 µm wide SIL shape is presented with a lens area two and a half times larger than the largest FIB SIL we created so far. The resulting wider opening angle has the potential of better spatial resolution and higher photon collection efficiency. 370 nm wide image features are resolved using the FIB created SIL expanding the resolution capabilities of the used laser scanning microscope considerably.