2. Cambridge NanoTech ALD Systems
• All Cambridge NanoTech ALD Systems are controlled with a
convenient Labview-PC-USB interface.
• All ALD systems have hot walls with cross-flow precursor
deposition. N2 gas is used for high speed pulse-purge cycles.
• Prior to deposition, a substrate is inserted into the ALD reactor,
and is heated usually between 50-400ºC.
Cambridge NanoTech Inc. Confidential 2
3. ALD Cycle for Al2O3 Deposition
Tri-methyl
aluminum Methyl group Methane reaction
(CH3) Reaction of product (CH4)
Al(CH3)3(g) H
TMA with OH
H Al C
C H
H Hydroxyl (OH) H H H
H
from surface H C C H
adsorbed H2O H
Al
H
O O
Substrate surface (e.g. Si) Substrate surface (e.g. Si)
Trimethyl Aluminum (TMA) reacts with the In air H2O vapor is adsorbed on most surfaces,
adsorbed hydroxyl groups, producing methane as forming a hydroxyl group. With silicon this forms:
the reaction product. Si-O-H (s). After placing the substrate in the
reactor, Trimethyl Aluminum (TMA) is pulsed into
the reaction chamber.
• Trimethyl Aluminum (TMA) reacts with the adsorbed
hydroxyl groups, producing methane as the reaction
product.
Al(CH3)3 (g) + : Si-O-H (s) :Si-O-Al(CH3)2 (s) + CH4
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4. ALD Cycle for Al2O3 Deposition
Methane
reaction
product CH4 H
Reaction of H C
TMA with OH H H
H
H
H C C H
H
Al
O
Substrate surface (e.g. Si)
• Trimethyl Aluminum (TMA) reacts with the adsorbed
hydroxyl groups, producing methane as the reaction
product.
Al(CH3)3 (g) + : Si-O-H (s) :Si-O-Al(CH3)2 (s) + CH4
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5. ALD Cycle for Al2O3 Deposition
Excess TMA Methane reaction
product CH4
H H
H C C
H
Al
O
Substrate surface (e.g. Si)
• Trimethyl Aluminum (TMA) reacts with the adsorbed
hydroxyl groups, until the surface is passivated. TMA does
not react with itself, terminating the reaction to one layer.
This causes the perfect uniformity of ALD. The excess TMA
is pumped away with the methane reaction product.
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6. ALD Cycle for Al2O3 Deposition
H 2O
O
H H
H H
H C C
H
Al
O
• After the TMA and methane reaction product is pumped
away, water vapor (H2O) is pulsed into the reaction chamber.
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7. ALD Cycle for Al2O3 Deposition
Methane reaction product
New hydroxyl group
Methane reaction
H Oxygen bridges
product
O
O
Al Al Al
O
• H2O reacts with the dangling methyl groups on the new
surface forming aluminum-oxygen (AI-O) bridges and
hydroxyl surface groups, waiting for a new TMA pulse.
Again, methane is the reaction product.
2 H2O (g) + :Si-O-Al(CH3)2 (s) :Si-O-Al(OH)2 (s) + 2 CH4
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8. ALD Cycle for Al2O3 Deposition
H
O
O O
Al Al Al
O
• The reaction product methane is pumped away. Excess H2O
vapor does not react with the hydroxyl surface groups, again
causing perfect passivation to one atomic layer.
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9. ALD Cycle for Al2O3 Deposition
H H H
O O O
O O
Al Al Al
O O O
O O
Al Al Al
O O O O
O
Al Al Al
O O O
• One TMA and one H2O vapor pulse form one cycle. Here
three cycles are shown, with approximately 1 Angstrom per
cycle. Each cycle including pulsing and pumping takes, e.g.
3 sec.
Two reaction steps Al(CH3)3 (g) + :Al-O-H (s) :Al-O-Al(CH3)2 (s) + CH4
in each cycle: 2 H2O (g) + :O-Al(CH3)2 :Al-O-Al(OH)2 + 2 CH4
(s) (s)
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10. ALD Cycle for Al2O3 Deposition
• The saturative chemisorption of each layer and its
subsequent monolayer passivation in each cycle, allows
excellent uniformity into high aspect ratio 3D structures,
such as DRAM trenches, MEMS devices, around particles, etc.
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11. ALD Deposition Advantages
Alternating reactant exposure creates unique
properties of deposited coatings:
• Thickness determined simply by number of cycles
• Precursors are saturatively chemisorbed => stoichiometric
films with large area uniformity and 3D conformality
• Relatively insensitive to dust (film grows underneath dust
particles)
• Intrinsic deposition uniformity and small source size =>
easy scaling
• Nanolaminates and mixed oxides possible
• Low temperature deposition possible (RT-400 ºC)
• Gentle deposition process for sensitive substrates
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12. Cambridge NanoTech ALD Systems
• Savannah - Thermal ALD System for R&D
– More than 100 systems sold
• Fiji – Plasma ALD System for R&D
– Next generation plasma ALD system
• Phoenix – Batch Production Thermal ALD System
– Batch production for Gen 2 substrates and wafers
• Tahiti – Large Surface Area Production Thermal ALD System
– Stackable chambers for Gen 4.5 substrates
Savannah Fiji Phoenix Tahiti
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13. Savannah ALD Systems
• World’s most popular ALD system for R&D
• Great films and easy to use
– System set up in under 3 hours
– Intuitive user interface very easy to learn
– Recipes included
Savannah S100 Savannah S200 Savannah S300
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14. Patent Pending ALD ShieldTM Trap
Flow direction
Coating
No coating
Cambridge NanoTech’s high
conductance hot foil ALD trap
forms a uniform solid coating
until the precursor is depleted.
Traps can be cleaned after 100
µm of coating.
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15. Fiji: Next Gen Plasma ALD System
• Revolutionary reactor design built from ALD
principals, NOT a converted CVD chamber:
– Contoured shape for laminar flow and uniform
depositions
– Design eliminates gate valves in the reactor
– Close mixing of precursor and plasma gases
• Based on world class Savannah ALD system
– Proven precursor delivery system
– Integrated ALD Shield vapor trap
• Modular design and many configurations
– Single and dual chamber configurations available
– Options include load lock, turbo pumps, and
automatic pressure control (APC)
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16. Sample Fiji Configurations
Single Chamber with Dual Chamber Dual Chamber with
Load Lock Cleanroom Façade
Also Available: Dual chamber with load locks, Single chamber with
clean room façade, and optional analysis ports in reaction chamber
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17. Phoenix Batch ALD System
Phoenix System Overview
• Batch ALD production system
– 5 GEN 2 substrates (370x470 mm)
– 52 wafers: 200 mm
– 78 wafers: 150 mm
– Large objects
• Deposition temperature: 85–285 C
• Uniformity < 3% 2-sigma (Al2O3)
• Small footprint: 700x700 mm
• Optimized for low maintenance
– stainless steel liner and trap easily
exchanged for periodic cleaning
– Exchange time approx. 1 hour
• Patent pending trap prevents coating inside the
pumping line and pump decreasing pumping line
and pump maintenance
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18. Tahiti ALD System
Tahiti System Overview
• Tahiti Large Surface Area production system
– 2 Gen 4.5 substrates
– Scalable to accommodate Gen 5 substrates
and larger
• Uniformity < 5% 3-sigma (Al2O3)
• Dual stacked chambers saves cleanroom space
• Optimized for low maintenance
– Stainless steel liner and trap easily
exchanged for periodic cleaning
• Patent pending trap prevents coating inside the
pumping line and pump decreasing pumping line
and pump maintenance
• Automation-ready with easy network
connectivity and on-board diagnostics.
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19. Cambridge NanoTech Summary
• Cambridge NanoTech is a world leader in ALD technology
– World-class ALD scientist led by Dr. Jill Becker, Founder
– Leading ALD research with association with Harvard Univ.
• Leader in ALD R&D systems with over 150 Savannahs worldwide
– Many satisfied customers and references
• Developed Phoenix and Fiji ALD systems under contract with CNT
customers
– Leading Semiconductor manufacturer hired CNT to develop
the Phoenix ALD production system
– Leading R&D Institute hired CNT to develop the next
generation plasma ALD system - Fiji
www.cambridgenanotech.com
See Website for additional information
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