Machine Tools And Devices For Special Technologies

1. Slovak University of Technology Faculty of Material Science and Technology in Trnava Machine Tools And Devices For Special Technologies Semiconductive component manufacturing

2. Semiconductive component manufacturing • Semiconductors are matters, those electric resistance is manifold greater as is electric resistance of metals and at the same time their resistance be of the essence smaller as is a resistance of insulating materials. • semiconductive materials are silicon, intermetallic allied substances AsGa, InP... • Basic raw material to semiconductive component manufacturing is slice cutted from monocrystal, which is wrought that its surface does not contain any crystallographic defect

3. Semiconductive part production sequence • Initial cleaning – zone melting • Monocrystal drawing • Mechanical treatment • Epitaxy • Lithographic techniques • Diffusion • Ion implantation • Contacting • Encasing • Cooling

4. Initial cleaning – zone melting • it needs enough purify base material  purity of base material must be very high suitable is usingof zone melting • High-frequency heating is realising by inductance. This way heating is very advantageous, because heat rise in entire section of ingot. Scheme of zone melting

5. Monocrystal drawing • ingot is compound from aggregate of chaotically placing crystals this is component manufacturing unusable, be needed the monocrystal with proper orientation of crystal grid - called monocrystal drawing by CZOCHRANSKI method. Monocrystal drawing

6. Mechanical treatment • With respect of alloys concentration the monocrystal is cutting by diamond saw to slices by thickness 0,1 till 2 mm - called WAFERs • Slice surface is after mechanical machining damaged to depths this is a reason for finally etched and glazed into high gloss Monocrystal splitting to wafers

7. Epitaxy • On the surface of slices material are allow accrue the additional silicon layer with the accurately defined concentration of additive material  this process of thin layer accretion is called epitaxy. • Epitaxy • from gas phase • from liquid phase • from organo - metallic phase

8. Lithographic techniques • Chosen slice surface parts were treat by doping process, we must at the slice surface to every doping process create a mask. • Advantages of the mask: • Very thin layer, • Homogeneous, • Without poorness, • All right adhere to base.

9. Lithographic techniques Masking layer is embossed by photolithography. On the base slice with layer of the SiO2is accrued the thin layer of photoresist. Rest of the photoresist is removed from the surface and the slice is prepared for next processing.

10. Diffusion • Penetration of the concrete material atoms into solid phase of semiconductive materials. • According to diffusion alloys generated: • Areas P • Areas N Both with suitable electrical properties. • In some cases the gold is used for diffusion.

11. Ion implantation • the process, by which donation run over at low temperature (ideal is temperature around 20°C) • To doping is used ions of atom of doping matters • Ionic implantator is a vacuum device • Ions forced in semiconductor slice are not integrated in crystal grid, hence it needs semiconductor slice normalize yet

12. Contacting • Cross interconnection within circuit is realising by conductive linkage networks • On circuit terminals from encasement is made the contact plate from Al  connecting between contact plate and output with wire attached with thermocompress welding.

13. Encasing • This is an important operation, important is suitable encasement selection, because mostly is the encasement the most expensive part of entire integrated circuit. • Case must satisfy entire row requirement: • Protect integrated circuit before environment, • Dissipate heat from IC into environment, • Allow manipulation with IC (soldering, assembly...), • Must be probably the cheeps.

14. Encasing • Used cases: • Metal • Ceramics • Plastic • Dimension and shape of casing are standardised.

15. Cooling • Casing consist thermal outlet where is connect external cooler.