Method for manufacturing semiconductor device by performing multiple ion implantation processes

摘要

A method for manufacturing a semiconductor device suppresses loss of vacuum in a chamber of an ion implanter, sag of a resist mask pattern for ion implantation, and producing a resist residue after ashing. First ion implanting process implants n-type impurity to form n+ impurity layer on the whole back surface of n− semiconductor wafer. A resist mask on the back surface of the wafer covers a part corresponding to where n+ cathode layer will be formed. A second ion implanting process implants p-type impurity using the resist mask to form p+ impurity layer in the interior of the n+ impurity layer. Second ion implanting process is split into two or more times. The dose of p-type impurity in second ion implanting process is greater than that of n-type impurity in first ion implanting process. The resist mask is removed, and p+ the n+ impurity layers activated.

主权项

1. A method for manufacturing a semiconductor device comprising the steps of:
performing a first ion implanting process for implanting an n-type impurity with a first dose on a surface of a semiconductor wafer to form an n-type impurity layer on the surface of the semiconductor wafer; coating resist on the surface of the side where the n-type impurity layer is formed in the semiconductor wafer; exposing the semiconductor wafer selectively to pattern the resist; and performing a second ion implanting process for implanting a p-type impurity with a second dose greater than the first dose using the remaining part of the resist as a mask to form a p-type impurity layer in the interior of the n-type impurity layer wherein Rp1, ΔRp1, Rp2, and ΔRp2 are defined as the projected range of the n-type impurity in the first ion implanting process, the standard deviation of the projected range Rp1, the projected range of the p-type impurity in the second ion implanting process, and the standard deviation of the projected range Rp2, respectively, and wherein the following equation 1 is satisfied as:
Rp2+3·ΔRp2≧Rp1+3ΔRp1  (1).