Patent ID: 9653299
Date: 2017-05-16
CPC Classifications: H01L

Claim:
1. A semiconductor device producing method comprising: entering a first laser pulse emitted from a semiconductor laser oscillator and having a first pulse width onto a second surface of a semiconductor substrate in which a semiconductor device is formed on a first surface, first dopants are added to a portion shallower than a first depth in a surface layer portion on the second surface side at a first concentration, and second dopants are added to a portion deeper than the first depth in the surface layer portion on the second surface side at second concentration lower than the first concentration; and entering a second laser pulse having a second pulse width less than or equal to 1/10 of the first pulse width in such a manner that an incident area of the second laser pulse is overlapped with an incident area of the first laser pulse, wherein a relative positional relationship on a time axis between falling time of the first laser pulse and rising time of the second laser pulse is set such that a temperature of the first surface, which rises due to incidence of the first laser pulse and the second laser pulse, does not exceed an allowable upper limit value which is predetermined, and wherein the first laser pulse is entered onto the second surface under a condition that the second dopants are able to be activated without the second laser pulse, wherein when the falling time of the first laser pulse is denoted by t