Wafer testing probes used in vertical probe cards are divided into two categories: MEMS probes and spring probes. Among them, MEMS probes have extremely fine diameters, featuring high consistency and stability. MEMS processes can fabricate metal microstructures with tiny diameters, meeting testing requirements such as fine pitch, elastic testing range, high pin count, and high density. Spring probes, meanwhile, are mostly used in WLCSP testing, offering advantages like low cost and convenient maintenance.