High-quality thin deposition

Since the thin-deposition occurs under the bombardment of high-density ions controlled at a low energy level of 10-30 eV, precise, high-quality thin films that are flat at the atomic level can be formed. In addition to SiO2 films that exhibit resistance to extreme conditions of 10 MV/cm, films of other materials can be obtained, such as Si3N4, which is as hard as diamond and has superior moisture blocking properties, and Al2O3, which provides a good barrier to hydrogen.

Low temperature, low damage

The ion-assist effect makes it possible to form thin films of chemical compounds such as oxides or nitrides without any high-temperature heating, and also makes it possible to obtain highly crystalline thin films at low temperatures. Since the ion energy is low, a soft cleaning effect with low damage to the substrate can be expected.

High-reactivity deposition

Any solid material that can be fabricated into a sputtering target can be used as the raw material, so thin films of various chemical compounds can be formed easily by combining them with introduced gases such as oxygen or nitrogen. For example, if Si is used as the solid source, Si, SiO2, and Si3N4 films can be formed, and if Al is used, Al2O3 and AlN films can be formed. We have also had results with Ta2O5, HfO2, and ZrO2 films, as well at ITO and STO films.

• Adhesion of films to the microwave introduction port is prevented and a branch coupling type of ECR plasma source that implements long-term stable operation is installed
• To ensure there are direct reactions between sputtering particles from the solid source and a low-energy, high-current ECR plasma flow (of oxygen or nitrogen, etc.), an environment-adapted system which makes exhaust gas processing unnecessary is used
• A clean deposition environment has been implemented by the adoption of a turbo molecular pump for the main exhaust from the deposition chamber, as well as a load lock mechanism
• The vacuum exhaust sequence is automated, and various interlock mechanisms have been adopted

ECR Principle

Electrons rotating within the confines of lines of magnetic force of a field strength of 87.5 mT (Tesla) are excited by an alternating electric field at 2.45 GHz (electronic cyclotron resonance), and absorb energy to rotate at high speed. This ensures that gas molecules collide, even at low pressures where discharge is difficult, to generate a plasma efficiently.

High refractive index control

• No electrical power, low gas pressure (0.01-0.2 Pa), large-current ion bombardment effect at low energies (10-30 eV) to a high-density (5-10 mA/cm²) substrate surface
• Formation of precise, smooth, high-quality thin films, with low heating and low damage

Physical properties of ECR thin films

Flatness

Tiny irregularities at the single-atom level (Rmax of Al2O3 film = 0.48 nm at a film thickness of 100 nm)

Hardness

SiN films and carbon films have hardnesses similar to those of diamond

Strictness

Waterproofing characteristics of SiN film (reliable blocking with SiN film coating)

Hydrogen barrier characteristics of AI2O3 film (barrier ability similar to bulk)

Superior optical characteristics

Highly precise refractive index control, high optical permeability (SiO2, SiN, AI2O3, AIN, Ta2O5, ZrO2, etc.)

Impurity-free

High-purity target and gas used as ingredients to achieve high levels of purity with no reaction products (H, F, CI, etc.)

High compoundability

Orientation of AIN films, MgO films, etc. Low-resistivity TiN films and α-Ta films.

Coatability

Coatability of bumps is much higher than with general sputtering, by formation of inclined rotation film at low gas pressure and high ionization rate.

High voltages

High-voltage insulation film similar to bulk. 10 MV/cm for SiO2 and Al2O3 films (similar to 1000°C thermal oxidation film).

Low damage

C-V characteristics of MOS capacitor using ECR-SiO2 film (implementation of superior boundary characteristics by unheated ECR oxide) Low boundary levels and boundary charges of MOS capacitor

High permittivity

Formation of boundary oxide films inhibited by metal-mode deposition