Facing Target / Low Damage Sputtering
The highly energetic nature of magnetron sputtering deposition makes it an ideal technology for many applications; however, certain aspects of the sputtering process can lead to challenges when depositing onto soft materials and organics. In a confocal or face-on-face sputter geometry (both of which have the sputter cathode pointing towards the substrate), high energy gas particles can be reflected off the face of the target to make contact with the substrate directly. As these high energy particles impinge upon the substrate, they can cause physical damage, most often ‘pinholes’, to any soft organic layers at the surface. These pinholes can have serious implications on film properties and overall device performance.
Another challenge with traditional magnetron sputtering is that although much of the electron density is captured at the surface of the target, some electrons interact with the substrate to create heat. If these interactions cause the substrate temperature to rise above what is safe for the layers that make up a device, performance will suffer.
Facing target sputtering – a technique in which two magnetron sources are positioned opposite one another and at right angles to the substrate – seeks to address each of these issues. The source configuration (having two sputter targets face directly towards one-another) provides a geometry in which any high energy reflected particles are directed to the opposing cathode, and not the substrate. This geometry – when paired with the appropriate source magnetics – also confines the plasma between the two sources and reduces the electron density which is allowed to reach the substrate. The result is a sputtering technology which minimizes both the physical and thermal damage of soft or organic layers.
Facing target sputtering is an excellent configuration if your process requires sputter deposition directly on top of a soft material. It should be noted that the off-axis geometry of this configuration leads to significantly decreased deposition rates compared to traditional confocal or face-on-face sputter deposition.
Facing target magnetron sputtering is available in a variety of source configurations and compatible with many of Angstrom’s process control capabilities and advanced fixturing options.
Aeres®, Angstrom’s advanced process control software, has been specifically configured with features and capabilities unique to high performance facing target magnetron sputter deposition. Click here to learn more.
For a background overview of magnetron sputter deposition, or to continue exploring other topics related to sputtering, please click the links below.
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