PECVD process allows to reduce substrate temperature which is critical to the device, whereas SACVD at high temperature and high pressure is used for high deposition rates. Featuring better step coverage than PVD technology, PECVD and SACVD are mainly used to deposit the critical insulating dielectric layers that isolate and protect the electrical structure, such as silicon oxides, silicon nitrides and low-K.

Except High Density Plasma deposition (HDPCVD), most of processes operate under primary vacuum, in the mbar pressure range. As the chemical reaction occurs in the chamber, precursors react to form by-products which are evacuated by vacuum pumps.

Such by-products are commonly a great challenge for the dry pumps as their nature may vary depending on the type of precursors which are used: Highly corrosive, condensable, or solid, some applications combining even all of these simultaneously.

Pfeiffer provides a full range of dry pumps designed to handle these challenges: Sophisticated thermal management prevents deposition, advanced materials reduce corrosion rate and multi-stage Roots design manages powder evacuation.

The most common PVD process used is sputtering technology: The target material is bombarded by the inert gas (mostly argon) ions generated in the plasma. Then the target material is ejected from the surface and deposits on substrate.

Such process operates at high vacuum below 10^-3 to 10^-7 Torr range, requiring the use of dry roughing pumps, turbopumps as well as cryo pumps. As there is no chemical reaction, this process generates no by-products and is therefore a clean application for vacuum pumps.

Pfeiffer supplies the A4H series, a full range of dry pumps and magnetically levitated turbopumps dedicated to PVD applications. Our ATH-M turbopumps are qualified on many PVD tools at major OEMs.

ALD deposition cycle consists of sequential injections of precursor and reactant in the reactor. Chemical reaction energy is activated either by temperature (Thermal ALD) or by plasma (PE ALD). In between each pulse, N₂ purge is injected to evacuate by-products formed by precursor adsorption on the surface and unreacted precursor and reactant.

As the reaction is self-limited by nature, film thickness is only dependent on the number of deposition cycles performed, allowing a control of the deposited layer at the atomic scale. ALD process can be performed on single wafer or batch equipment, each of them featuring specific advantages.

Most of ALD processes operate under primary vacuum, in the 10^-1 to 5 mbar pressure range. On high volume manufacturing equipment, high pumping capacity in the range of 1,800 to 4,500 m³/h is required for fast evacuation of precursors during purge steps, insuring high throughput.

On smaller R&D equipment, smaller dry pumps can be used, between 600 to 1,200 m³/h. Generated by-products are commonly a great challenge for the dry pumps as their nature may vary depending on the type of precursors which are used: Highly corrosive, condensable, or solid, and some applications combining all these simultaneously.

Pfeiffer provides the A4 series, full ranges of dry pumps designed to handle these challenges: Sophisticated thermal management prevents deposition, advanced materials reduce corrosion rate and multi-stage Roots design manages powder evacuation.

Both LPCVD & Diffusion technologies use thermal energy to activate the chemical reaction, typically in the range of 500 to 900 °C. Besides excellent step coverage & high purity deposition, this technology allows a much larger substrate surface treatment than other CVD technologies. LPCVD or Diffusion equipment are commonly batch types, processing up to 200 wafers simultaneously.

Depending on the material to be deposited, several precursors can be used leading to multiple varieties of by-products to be handled by dry vacuum pumps: Condensable or solid, some applications combining both simultaneously.

Considering the numbers of wafers processed in a batch furnace, dry pump robustness & process lifetime are critical to insure production throughput: The A4 Series is the perfect fit to meet these challenges.

In solid source MBE, ultra-pure elements such as gallium and arsenic are thermally evaporated in vacuum (from 10^-8 hPa (mbar) to 2x10^-5 hPa (mbar) typical). The atomic fluxes from the cells reach the wafer where the epitaxial growth can happen. In the example of gallium and arsenic, single-crystal gallium arsenide is formed. The atoms impinging on the surface adsorb, migrate and incorporate into crystalline lattice of the wafer. They also can desorb if the substrate temperature is too high.

Controlling the temperature of the source will control the rate of material impinging on the substrate. The substrate temperature affects the migration length and desorption rate. The term "beam" means that evaporated atoms do not interact with each other or residual gases until they reach the wafer, due to the long mean free paths of the atoms at low pressure. Therefore, simple mechanical shutters can be used to abort the flux.

Vacuum is essential in Molecular Beam Epitaxy (MBE) to ensure high purity of grown films by minimizing contamination from residual gases. The ultra-high vacuum environment allows precise control of atomic fluxes from evaporation sources to the substrate, facilitating high-quality epitaxial growth. It also prevents contamination from external sources, crucial for semiconductor devices and Nano-Quantum technologies.

The vacuum helps control substrate temperature, affecting the migration length and desorption rate of atoms, which is vital for achieving the desired crystalline structure. MBE takes place in high vacuum or ultra-high vacuum (10^-8 – 10^-12 hPa (mbar)) with a typical deposition rate of 1,000 nm per hour, requiring better vacuum conditions to maintain low impurity levels.

The absence of carrier gases and the ultra-high vacuum environment achieve the highest purity of grown films. Pfeiffer offers various vacuum pumps, gauges, and mass spectrometers designed for MBE applications to ensure ideal vacuum conditions and high-quality epitaxial growth.

Pfeiffer provides different dry rough pumps and turbopumps with high compressions ratios. For MBE applications, Pfeiffer also can provide vacuum gauges to control the pressure in the system and mass spectrometers to perform the residual gas analysis (RGA).