Electron beam pattern transfer device and method for aligning mask and semiconductor wafer

摘要

According to the invention an electron beam pattern transfer device with an improved alignment means is provided. A first and a second mark M1, M2 for alignment purposes are formed on the surface of the wafer and the wafer holder, respectively. The first mark M1 is formed on the wafer by conventional lithographic technique and the second mark M2 consists of a hole or a heavy metal, such as Ta or Ta2O5. A third alignment mark M3 is provided on the photocathode mask having a position corresponding to M2 on the wafer holder and spaced a known distance L2 from an imaginary reference position M4 on the mask. The first step of the alignment process requires the detection of a relative distance L1 between the first and second marks M1, M2 by conventional detecting means, such as an optical measuring means. In the next step, the relative position of the photocathode mask and the wafer holder is adjusted so that the distance between the marks M2 and M3 is made substantially equal to the difference between the distance L1 and the known distance L 2.