WAFER PROCESSING METHOD

PROBLEM TO BE SOLVED: To provide a new wafer processing method capable of appropriately dividing a wafer including a metal layer overlapping with an intersection region with which division schedule lines intersect.SOLUTION: A wafer processing method includes: a modified layer forming step of forming a first modified layer along a first division schedule line and a second modified layer along a second division schedule line inside a wafer except a non-processing region in an intersection region with which the first division schedule line and the second division schedule line intersect by irradiating the wafer with a laser beam of a wavelength having permeability to the wafer along the first division schedule line and the second division schedule line; and a division-promoting modified layer forming step of forming a division-promoting modified layer for promoting division in a portion overlapping with a metal layer in the non-processing region by irradiating the portion overlapping with the metal layer with the laser beam of the wavelength having the permeability to the wafer.SELECTED DRAWING: Figure 4 【課題】分割予定ラインの交差する交差領域に重なる金属層を備えるウェーハを適切に分割できるように加工する新たなウェーハの加工方法を提供する。【解決手段】ウェーハの加工方法であって、ウェーハに対して透過性を有する波長のレーザービームを第１分割予定ラインと第２分割予定ラインとに沿って照射し、第１分割予定ラインと第２分割予定ラインとが交差する交差領域内の非加工領域を除くウェーハの内部に、第１分割予定ラインに沿う第１改質層と第２分割予定ラインに沿う第２改質層とを形成する改質層形成ステップと、非加工領域の金属層と重なる部分にウェーハに対して透過性を有する波長のレーザービームを照射し、金属層と重なる部分の分割を促進させる分割促進用改質層を形成する分割促進用改質層形成ステップと、を含む。【選択図】図４