The document discusses different thin film production processes: electron-beam evaporation, thermal evaporation, ion assisted deposition (IAD), and ion beam sputtering (IBS). Each process has its own advantages and limitations for producing optical thin films. For example, evaporation processes are low-cost but substrates have material restrictions, while IBS provides highly stable and durable coatings but is more expensive and not applicable for some wavelengths. Manufacturers often only use one process despite different needs for coating applications.

1. Thin Film
Production

2. Understanding Thin Film Process
Technologies
• There are currently a number of different processes used for the
manufacture of optical thin films, the most common of these being
• E-beam and Thermal Evaporation
• Ion Assisted Deposition (IAD)
• Ion beam sputtering (IBS)
• If properly utilized, each of these techniques has value, and possesses its own
unique advantages and limitations. Unfortunately, many coating manufacturers
use only one of these methods, and therefore attempt to make it appear that their
single approach is uniquely advantageous for all application

3. E-beam and Thermal Evaporation
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4. • Traditional electron-beam and thermal evaporation are the most
widely employed methods for producing thin films because of their
simplicity and relatively low cost of implementation.
• Here, a coating material is heated either resistively (for metals) or
through electron beam bombardment (for dielectrics) within a high
vacuum chamber until it vaporizes.
• This vapor then streams away from the source and recondenses on
all surfaces that are in a line of sight with the source.
E-beam and Thermal Evaporation

5. • Primary advantages:
• Low cost
• Works with coating materials from the deep UV through the
infrared
• Primary disadvantages:
• Heat cycling during processing can limit substrate choice and
introduce internal stress
• Lower environmental stability and mechanical durability
•
E-beam and Thermal Evaporation

6. Ion Assisted Deposition (IAD)
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7. Ion Assisted Deposition (IAD)
• IAD is a variant of the electron-beam evaporation process which
adds a high energy ion beam that is directed at the part to be
coated.
• These ions act almost like an atomic sized hammer, producing a
higher film density than can be achieved with purely by
evaporation alone.
• The ion beam can also be used to pre-clean or etch the surface of the
substrate, which can improve film adhesion.

8. • Primary advantages:
• Enhanced density provides good compromise between cost, spectral
stability and durability
• Can be selectively employed from the UV through the IR
• Doesn’t require heating the substrate which broadens material
choices
• Primary disadvantages:
• Higher scatter and loss than IBS
Ion Assisted Deposition (IAD)

9. Ion beam sputtering (IBS)
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10. Ion beam sputtering (IBS)
• IBS coatings are produced in a vacuum chamber.
• In IBS, a high energy ion beam is directed at a target, typically
composed of a metal or oxide.
• The ions transfer their momentum to the target material, causing
atoms or molecules to sputter off.
• These high energy atoms then deposit onto the parts to be coated.
• Oxygen is typically present at low pressure in the coating chamber
as a reactant to either create oxides when using metal targets, or to
re-oxidize any free atoms dissociated by the sputtering process
when using oxide targets

11. • Primary advantages:
• Delivers the ultimate in stability and durability
• Lowest possible absorption and scatter of any coating technology
• Doesn’t require heating the substrate which broadens material
choices
• Enables accurate process control resulting in high precision coatings
• Primary disadvantages:
• Not applicable in the deep UV or far IR
• Higher cost than evaporative due to longer cycle times
Ion beam sputtering (IBS)