Process for treating a substrate using a luminous flux of determined wafelength, and corresponding substrate

A method of treating a substrate using a luminous flux of determined wavelength, comprising:

• providing a substrate comprising an embedded layer interleaved between a first layer and a second layer, the embedded layer configured to absorb the luminous flux independently of a temperature of the embedded layer, the first layer having a low coefficient of absorption of the luminous flux at ambient temperature, the coefficient of absorption rising as a temperature of the first layer rises;
• and
• applying the luminous flux to the substrate through several places on a surface of the first layer, the applied luminous flux heating regions of the embedded layer and generating a propagating thermal front resulting in heated zones in the first layer in the form of expanding thermal pillars, the expanding thermal pillars generating constraints within the second layer resulting in structural defects in a region of the second layer, the structural defects weakening the region of the second layer.