Wafer breaking method and chip failure analysis method

A wafer breaking method, comprising:

• providing a wafer sample, wherein the wafer sample comprises a first surface with a target point and a second surface opposite to the first surface;
• forming a first crack and a second crack respectively at edges of the wafer sample, wherein orthographic projection of the first crack and the second crack on the first surface are on the same straight line as the target point in a preset direction;
• forming a cutting slot in the preset direction on the second surface, wherein there is a preset distance between a bottom of the cutting slot and the first surface, and orthographic projection of the first crack and the second crack on the second surface are on the same straight line as the cutting slot;
• and
• breaking the wafer sample along the cutting slot, such that the wafer sample is broken in the preset direction, so as to obtain a cross section of the target point in the preset direction.