Amorphous Silicon Coatings for Control of Corrosion and Metal Ion - - PowerPoint PPT Presentation

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Amorphous Silicon Coatings for Control of Corrosion and Metal Ion - - PowerPoint PPT Presentation

Jan 24, 2023 327 likes •495 views

Amorphous Silicon Coatings for Control of Corrosion and Metal Ion Contamination James B. Mattzela, D.A. Smith, M. Yuan, J. Bischof, & L. Patterson SilcoTek Corporation Bellefonte, PA USA Motivation Purity increasing in importance

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SLIDE 1

Amorphous Silicon Coatings for Control of Corrosion and Metal Ion Contamination

James B. Mattzela, D.A. Smith, M. Yuan, J. Bischof, & L. Patterson

SilcoTek Corporation · Bellefonte, PA USA

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SLIDE 2

Motivation

  • Purity increasing in importance
  • Pushing physical limits
  • Devices become smaller
  • Metal ion contamination more important
  • Etch (and cleaning) chemistries
  • Number of removal steps increasing
  • Gas chemistries more aggressive
  • Corrosion limits productivity

Game-Changing Coatings™ 2

Image from Li, Y. and Quader, K.N. NAND Flash Memory: Challenges and Opportunities. Computer 2013, 46 (8), 23-29.

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SLIDE 3

Silicon Coatings Technology

  • Gas Chromatography
  • Robust alternative to glass columns
  • Oil and Gas
  • Accurate ppm-to-ppb detection
  • Environmental Sampling
  • Accurate ppm-to-ppb detection
  • Corrosion Resistance
  • Affordable alternative to superalloys

Game-Changing Coatings™ 3

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SLIDE 4

Industrial CVD

  • Commercialized process
  • 3-D deposition allows coating of all surfaces
  • High aspect ratio
  • Complex geometries
  • Bonded to substrate material
  • Wide range of substrate materials
  • Stainless steel, glass, ceramics, aluminum,

superalloys

  • Scalable process
  • Fittings to chambers
  • Thin coating: ~100 nm up to nearly 2 μm
  • Does not impact drawing dimensions or

tolerances

Game-Changing Coatings™ 4

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SLIDE 5

Advantages

  • Thermally stable
  • Wide operating temperature range
  • Reasonable cost
  • Superalloys are much more expensive
  • Environmentally known
  • Silicon is a primary material
  • Amorphous
  • Conformal over edges
  • Allows for mechanical flexing
  • Low outgassing
  • Vacuum compatible
  • Barrier to substrate effects (moisture or outgassing)

Game-Changing Coatings™ 5

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SLIDE 6

Coatings Composition

Game-Changing Coatings™ 6

Auger Electron Spectroscopy (AES)

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SLIDE 7

Improved Vacuum Pumpdown

7 Game-Changing Coatings™

  • Evacuation test
  • n fixed volume

chamber

  • Corrected for

background

  • utgassing
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SLIDE 8

Coatings Composition

Game-Changing Coatings™ 8

No metal (Fe, Cr, Ni) signal detected Oxygen Carbon Silicon X-Ray Photoelectron Spectroscopy (XPS) Focused Ion Beam (FIB) Field-Emission Secondary Electron Microscopy (FESEM)

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SLIDE 9

Corrosion Testing

Game-Changing Coatings™ 9

  • Follow ASTM G31-72(2004) “Standard Practice for Laboratory

Immersion Corrosion Testing of Metals”

  • Measure Mass Loss During Immersion
  • Calculate Corrosion Rate in mils per year (mpy)

Standard Coupon Corrosive Immersion

Corrosion Rate Weight loss (g) • K-factor Density (g/cm3) • Area (A) • Time (hr)

=

Calculate

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SLIDE 10

HCl Corrosion Testing

  • Test Conditions
  • 6 M HCl
  • Room temperature solution
  • 24 hrs of exposure

Game-Changing Coatings™ 10

Uncoated 316L S.S. a-Si:H coated 316L S.S. 30x more material lost on uncoated coupon

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SLIDE 11

Elevated Temperature HCl Corrosion Testing

  • Test Conditions
  • 6 M HCl
  • 50° C solution
  • 7 hrs of exposure

Game-Changing Coatings™ 11

Uncoated 316L S.S. a-Si:H coated 316L S.S. 30x more material lost on uncoated coupon

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SLIDE 12

HBr Corrosion Testing

  • Test Conditions
  • 6 M HBr (gas dissolved in DI Water)
  • Room temperature solution
  • 72 hrs of exposure

Game-Changing Coatings™ 12

Uncoated 316L S.S. a-Si:H coated 316L S.S. 7x more material lost on uncoated coupon

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SLIDE 13

Data Extrapolation

  • How long will the coating last in service?

Typical Maintenance Cycle – 3,000 RF Hours Improvement of coated vs uncoated is ~7.21x (using exposure to 6 M HBr for 72 hrs at r.t.) Possible Lifetime Extension – 23,000+ RF Hours

Game-Changing Coatings™ 13

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SLIDE 14

Plasma Exposure

  • 50 W SF6 remote plasma exposure (3 min exposure)
  • Stainless steel appears to begin to pit
  • Some etching of silicon

14 Game-Changing Coatings™

Bare 316L a-Si:H coated 316L

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SLIDE 15

Conclusions

  • Amorphous, hydrogenated silicon can be used as a barrier coating

for gas delivery in both etch and deposition environments.

  • CVD deposition of a-Si:H offers unique benefits including non-line-
  • f-sight deposition on existing components and good adhesion to

a wide variety of commonly used materials.

  • Additional benefits from a-Si:H deposition may be seen in low
  • utgassing of surfaces in vacuum and low particulate creation

from gas-surface interactions.

Game-Changing Coatings™ 15

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SLIDE 16

Future Directions

  • Develop method for characterizing gas corrosion
  • Develop method for characterizing coating lifetime in direct

plasma environment

Game-Changing Coatings™ 16