| 摘要 |
To provide a laser processing method and a laser processing device having a high processing speed and high energy efficiency. A laser processing method for forming a modification region serving as a starting point of cutting inside a member 3 to be cut along a planned cutting line S0 by relatively moving an optical axis O of a condenser lens 21 along the planned cutting line S0 of the member 3 to be cut and by irradiating the member to be cut with focused laser light, characterized in that a plurality of cross-sectional focused spots P0, P1, ···, is simultaneously formed on a section 3b which is perpendicular to the optical axis O of the condenser lens 21 at positions having a predetermined depth from a surface 3a of the member 3 to be cut and which is parallel to the surface 3a and, at that time, at least one cross-sectional focused spot of the plurality of cross-sectional focused spots P0, P1, ···, is formed on a projection line of the planned cutting line S0 onto the cross section 3b, and thus one or more inside modification regions having a desired shape are formed. |
