The invention discloses a method for
machining a TI-IGBT
chip back structure, and belongs to the technical field of the micro electronic. The method comprises the steps that after a
wafer front structure is machined,
P type doping is poured into the back face of a
wafer; the back face of the
wafer is coated with
photoresist, and
exposure is sequentially carried out on different areas, divided by a back
mask plate, of the phototesist on the back face of the wafer, wherein the
mask plate pattern comprises a plurality of pattern units symmetrically arranged in a horizontal movement mode; the relative position of the
exposure areas is controlled, and the
exposure patterns of the whole wafer are continuously symmetric in a horizontal movement mode based on the pattern units; N type
doping is poured into the back face of the wafer after development, the
photoresist on the back face is removed, and finally, back metallization is carried out after annealing activated
doping. According to the method, TI-IGBT with different voltages and different current levels can share the same back
mask plate, a large amount of plate making cost is saved, and production efficiency is improved.