Fig. 1. (a) "Forward" cleaning; (b) "Back" cleaning

Fig. 2. (a)-(d) Temperature distribution of particle and substrate with time under the "forward" action of 280 mJ laser energy; (e) Temperature-time change curve of the contact part between the particle and the substrate at different energies

Fig. 3. (a)-(b) Temperature distribution cloud image of particle and substrate at 280 mJ energy under laser "back" action and enlarged image of contact part (isotherm cloud image); (c) The temperature-time curve of the contact part between the particle and the substrate under different energies

Fig. 4. (a) Relationship between contact radius and particle size; (b) Relationship between adsorption force and particle size; (c) Relationship between particle temperature rise and laser energy and particle size; (d) Relationship between thermal stress and laser energy and particle size (Attached figure: thermal stress curves of 0.5 μm particles (black) and 1 μm particles (red))

Fig. 5. (a)-(b) The thermal stress distribution cloud of the particle substrate and the stress-time change curve of the contact point between the particle and the substrate during "back" cleaning; (c)-(d) Cloud map of thermal stress distribution of the particle substrate and stress-time change curve of the contact point between the particle and the substrate during "forward" cleaning

Fig. 6. Experimental process diagram

Fig. 7. (a), (b) Electron microscopy of the substrate particles and their particle size distribution

Fig. 8. (a), (b) The "forward" cleaning effect under 160 mJ (0.815 J/cm²) and 220 mJ (1.120 J/cm²) laser energy; (c), (d) Residual particle distribution and its particle size distribution curve at 280 mJ (1.426 J/cm²) laser energy

Fig. 9. (a), (b) cleaning effect and residual particle size distribution at 160 mJ （0.815 J/cm²） laser energy; (c), (d) Cleaning effect and residual particle size distribution at 220 mJ（1.120 J/cm²） laser energy

Fig. 10. (a) Pattern of pits formed by "forward" cleaning (typical particle size is marked in the figure); (b) An enlarged image of a single pit as indicated in Fig.(a); (c) Deformation of the substrate surface resulting from "back" cleaning; (d) An enlarged image of the irregular pits as indicated in Fig.(c)