Etching silicon tips in potassium hydroxide (KOH) solution has the advantages of simplicity, easy to handle, low-cost and homogeneous etching rate of the (100) crystal plane. But the opening angle of silicon tips etched in pure KOH solution or KOH solution saturated with isopropyl alcohol (IPA) addition is usually greater than 40° before sharpening, which is not suitable for probing samples with steep trenches and inclined side walls. This paper presents a novel method of etching silicon tips of small opening angle employing anisotropic wet etching in KOH solution with the addition of I 2 /KI. The silicon tips show a geometry similar to ‘rocket tip’ which can only be fabricated by dry etching before and fit for probing samples with deep trenches and inclined side walls.