Evaluation of Separating Process for Different Materials by Thermal Stress Cleaving Technique

 
 
 
  • Abstract
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  • References
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  • Abstract


    This paper aims to evaluate the separating process of brittle materials by thermal stress cleaving technique. This process is suitable for separating thin brittle materials such as sapphire and silicon wafer, which are sensitive to force.  Both materials were used largely in microelectronics, solar cells and micro-mechanical industries that require precise machining. Finite element method was used to evaluate a steady state thermal stress by considering the temperature transient during laser irradiation process. The heat source was assigned according to the laser energy absorption characteristics of the materials. Stress intensity factor was analyzed to determine the starts of separation process. The results show that CO2 laser energy was absorbed on the surface of the sapphire material as compared proportionated absorption of Nd:YAG laser energy on silicon material. Due to thermal stress generated by the laser beam, material separation was start. Fracture begins at the bottom surface of sapphire wafer compared to fracture initiation at the prepared groove for silicon wafer. The material separation can be controlled when it begins at the groove. Hence, better surface finished can be achieved.       

     

     


  • Keywords


    Thermal stress cleaving, stress intensity factor, sapphire, silicon.

  • References


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      [5] T. Ueda, T. Mino, T. Furumoto, A. Hosokawa, S. Nagatomo, Laser cleaving of sapphire wafer with pulsed wafer, Journal of the Japan Society of Grinding Engineers, 55(7), pp.424-426, 2011. (Japanese language)

      [6] D. Triantafyllidis, J. R. Bernstein, L. Li, and F. H. Stott, Dual laser beam modification of high alumina ceramic, Journal of Laser Applications 15(1), pp. 49–54. 2003.

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      [8] Anthony C. Fischer-Cripps, Introduction to Contact Mechanics, Springer US, 2007.


 

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Article ID: 22507
 
DOI: 10.14419/ijet.v7i4.27.22507




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