CVD Diamond:
Processing
Laser cutting

Polishing

Metallization
Laser cutting

Laser cutting of CVD diamond

Due to the extreme hardness of diamond a mechanical cutting or sawing of the diamond wafers is not possible. For that reason a Q-switched Nd:YAG laser is applied for cutting them into desired shapes. 

Polishing

 

After deposition, the coarse grained films are ground and polished to the desired thickness. For this purpose a high speed lapping machine capable of treating three samples simultaneously has been developed. Diamond wafers with up to 4" in diameter can be polished. 



Rms roughness values as low as 20 Å can be achieved under optimized conditions.  
Laser interferogram of a polished 2" diam. diamond disk (at 633 nm).

The appearance of only one interference fringe demonstrates the perfect surface flatness


Metallization For the preparation of diamond heat-spreaders the metallization is of central importance. Various metallization schemes consisting of several metal layers have been developed. Each layer acts either as adhesion layer, diffusion barrier, or as surface layer improving the wetting behaviour of the solder. Thick gold layers are used as electrical conductors for high current densities. 



Custom specific metallization schemes - for example metallized heat-spreaders with electrical isolation between the top and the bottom metallization - have been developed. Furthermore patterned metallizations prepared by photolithography are available. 
         

   

 © 2004
Fraunhofer IAF

  

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