Applications

Architectural and Anti-Reflective Glass | Solar Technology | Display and Web Coating | Automotive and Decorative Coating
 

 

Architectural and Anti-Reflective Glass

The first large scale commercial use of rotary magnetron sputtering technology was in the field of large area glass coating. First introduced by Airco Coating Technologies in the late 1980s, rotary magnetron reliability has improved by an order of magnitude since their introduction. Today there are tens of thousands of rotary magnetron cathodes being used in the large area glass coating fields.

When depositing large area coatings, reliability is key. Coating campaigns in these types of coaters can last from one week to over one month between vents. The component lifetimes in rotary magnetrons are very well know making preventative maintenance an easy way to maximize reliability. Through advancements in design and quality control, some rotary magnetrons can be maintained onsite by the customer for many years of trouble-free operation.

Rotary magnetron technology is often used for reactive sputtering processes such as silicon nitride, silicon dioxide, niobium pentoxide, and titanium dioxide due to its improved arc rates and higher achievable power densities as compared to planar targets.  For metallic layers, the primary benefit comes from higher material utilization. For both cases, cylindrical cathode sputtering reduces the overall cost of production while at the same time improving the quality.
 


 

Solar Technology

Rotary magnetron sputtering technology is used in all major forms of solar cell technology. 

Silicon Based technologies

Silicon based technologies were the first commercially developed photovoltaic products and still maintain a dominant market share today. Though other processes are used for the production of the silicon, sputtering is widely used to produce back reflector layer (predominantly aluminum) and front contacts made from transparent conducting oxides (TCO). TCO materials reap substantial benefits in performance, economics, and quality from the use of rotary magnetrons.

CIGS and CdTe

Known collectively as “thin film solar” technology, these two types are generally used on flexible substrates such as thin stainless steel, though rigid substrates such as glass are still used.

In addition to the traditional aluminum and TCO coatings, these technologies employ additional sputtered layers such as molybdenum and intrinsic zinc oxide. The increased cost of molybdenum (relative to aluminum) has led most major manufacturers to choose rotary magnetron technology due to its improved material utilization. Intrinsic zinc oxide can be produced using mid-frequency AC sputtering at much higher rates than the traditional RF technology used with planar cathodes.

Solar Thermal

Solar thermal technology uses the heat of the sun to increase the temperature of a liquid such as water or oil. The heat from this technology is then used directly (such as with solar water heaters) or indirectly to generate electricity.

Typically, rotary magnetron sputtering is used to generate anti-reflective coatings (to allow to solar energy to pass through protective coverings (such as glass), reflective coatings for solar collectors, or in absorbing coatings which allow the maximum capture of solar radiation. These absorber coatings can be made from Molybdenum and Al2O3. Al2O3 sputtering by rotary magnetrons is advantageous due to the high power densities (and therefore deposition rates) and low arc rates resulting from the elimination of redeposited oxide on the target surface.
 


 

Display and Web Coating

Rotary magnetron (cylindrical cathode) technology is broadly used in display manufacturing, both for rigid and flexible display applications.

TFT-LCD technology makes use of TCO materials (predominantly ITO) to provide the transparent electrode on the front side of the LCD pixel. Additional materials, such as silicon dioxide are used as insulating, adhesion and encapsulating layers in the overall TFT stack. Rotary ITO has substantial economic benefits over planar ITO: production costs (equipment, material, energy) can be reduced by over one half as compared to planar ITO while at the same time improving film quality.

The same benefits hold true for flexible substrates. In additional to the cost savings and quality improvements, temperature sensitive substrates reap additional benefits from rotary cathode technology. Due to the more efficient cooling dynamics of the rotary cathode, users will be able to coat films at higher rates, while imparting less heat to the substrate.

 

 


Automotive and Decorative Coatings

Until recently, most automotive and decorative coatings were accomplished using technologies such as evaporation, cathodic arc, or planar magnetron deposition.

Several recent developments have allowed rotary magnetrons to penetrate this market. First, costs of rotary magnetrons have declined considerably over the past 5 years. For most automotive/decorative size coaters, rotary cathodes price comparably to planar magnetrons. This allows the user to take advantage of the higher material utilization offered by cylindrical cathodes without an increase in the upfront cost. In addition to the material savings, users are required to change targets far less often, in some cases as little as one-tenth as often as with planar targets.

Secondly, several advances in rotary magnetic designs offer advantages to the end user. The advent of stronger magnetics allows not only thicker targets but also lower operating pressures, which can increase throw distance and improve coating uniformity of three-dimensional substrates. Magnetrons are also available with a variety of sputtering angles or even variable sputtering angles by rotating the magnet bar with the Swing Cathode feature, which allows the user the ultimate flexibility when coating complex shapes.

In addition to the various rotary magnetron products, SCI offers the envis-ION™ Dual Magnetron Pre-Treatment Source for automotive and decorative applications. The DMPTS is capable of providing effective pre-treatment of plastic substrates as far as 200 mm from the source. This source is capable of operating using standard sputtering power supplies and at standard sputtering pressures. In some cases, the source may also be used to provide a protective SiO2 under/overcoat to decorative metals.