Machine Tools And Devices For Special Technologies Ion beam machining Slovak University of Technology Faculty of Material Science and Technology in Trnava

Processing by ion beam These devices are based on the influence of high energic ions to machined surface. It is as micromachining and expanding mainly in production of semi finished components.

Processing by ion beam Advantages: All kinds of material, High quality of surface, High quality of accuracy (under 100 nm), High rate of material removing. Disadvantages: Expensive device, Vacuum is needed

Principle of becoming of ion beam Ion beam is a beam of high energic ions of inert gas (Ar, Xe). Electric charged elements (ions) impacted with high energy to machined material surface. Elements are accelerated and directed by electromagnetic field. Processes on the workpiece surface can be: dynamical, reactive.

Dynamic influence of ion beam Shooting out the surface atom from the workpiece by electro elastic crash. Atom by crash leave his place in crystal structure and can moving or to expel next atoms – sputter coating. Ions with low energy are reflected, ions with high energy stayed in the crystal structure like as implantate ions.

Dynamic influence by ion beam Material atoms in the depth layers have not sufficient energy for emitting and that is why they stay like interstitial atoms and in the structure is staying the vacancy – originated static of crystal structure. In the ion impact can originated emission of other kind (electron, photon, RTG). There can becoming radiation damaging of material.

Reactive influence by ion beam It is used by active ions. Mainly in production semi finished workpieces. Al – CCl 4, Si – CF 4, Process of material removing is faster as in the case of chemical machining because here is used activate energy of impacted ions.

Using of ion beam in the praxis Engraving by ion beam – base technology in production of semi finished components Reactive ion etching – surface is bombarded by reactive ions ( CF 4 +, CF 3 +, F + ), mask on the surface must be resist to their influence. Ion flashing – ions pressed from the surface particular atoms and take a their place, dimension is not changed. Ion implantation – ions permeate more deeply into material, the structure and chemical consist is changed.

Engraving by ion beam Make possible very precisions machining of strong materials. It is used for: Finishing of the ultra accurate lens, Sharping of diamond tools, Production of masks in semi finished industry, Surface finishing of the mono crystals.

Engraving by ion beam

Device for accurate processing of lenses

Ion implantation Into the base material are implanted ions of suitable elements (substances). Process is depend on: Combination between ion and support material, Energy of impacted ions (until 150 keV), exposition – securite ion concentration (10 16 until ion.cm -2 ), Processing temperature – securite moving of the base material atoms (20 till 100 °C), Quality of the vacuum and cleaning of the surface.

Ion nitridation Concentrating of that surface layer of steel by nitride. Here is originated thin strong coating of nitride of ferrum. Workpiece is cathode and room is anode, Nitride from surface layer absorbed by diffusion until the depth 0,3mm, Thickness of the surface nitride layer is about 5  m micro hardness till 900 HV, Fast process

Device for processing by ion beam By construction of ion source is possible to devide them: With ion sprinkle, High frequency plasma, Duoplasmatron.

Scheme of device for ion beam (ion sprinkle) processing

Scheme of device for processing by ion beam (ion sprinkle) 1 – anode, 2 – Heating of cathode, 3 – input of argon, 4 – source room of ion, 5 – suppresion of electrons, 6 – flying electrons, 7 – flying electrons, 8 – excitation coil, 9 – covering, 10 – directed flow of electrons, 11 – workpiece, 12 – room, 13 – air pump, 14 – neutralisation fibre, 15 – isolator, 16 – perforated electrode

Device activity for processing by ion beam (ion sprinkle) Argon is ionised in the vacuum room by electrons from straight heating electrode Flow of argon ions crossing through perforated electrode to the workpiece. Processing voltage of device is around 600V and flow intensity till 1 mA.cm -2. Machining speed of SiO 2 is in the rate of 0,5 till 0,7 nm.s -1.