# Presentation: 093158

## Superconformal Film GrowthBuilding intricate 3-D structures

- Dr. Thomas P. Moffat
- Dr. D. Wheeler, Dr. . C. H. Lee, Dr. D. Josell

##  Superconformal electrodeposition

- Objective:
- Building intricate 3-D metal structures and/or smoothing non-planar surfaces
- Key process: Void and seam-free filling of recessed surface features with metals and alloys ranging from passive 3-D conductors to active magnetic elements and alloys.

-  Superconformal electrodeposition

- IBM

##  Superconformal electrodeposition

- Objective:
- Building intricate 3-D metal structures and/or smoothing non-planar surfaces
- Key process: Void and seam-free filling of recessed surface features with metals and alloys ranging from passive 3-D conductors to active magnetic elements and alloys.

-  Superconformal electrodeposition

- IBM

## Superconformal or “Bottom-up” Filling of Submicron Features

- Superconformal** **or “Bottom-up” Filling of Submicron Features

- As a function of TIME

- As a function of ASPECT RATIO

## Advantages and Opportunities
Build interconnected or isolated 3D metal structures that are easily integrated with existing platforms associated with CMOS, MEMS, etc
New avenue for device manufacture & the possibility of novel architectures otherwise unavailable with existing processes

- Build interconnected or isolated 3D metal structures that are easily integrated with existing platforms associated with **CMOS, MEMS**, etc
- New avenue for device manufacture & the possibility of novel architectures otherwise unavailable with existing processes

- www.tms.org/.../JOM/9903/Frear-9903.fig.5.lg.gi

**ITRS**

## Understanding

- How general is the phenomenon ?

**1.**** ****C****urvature ****E****nhanced ****A****ccelerator ****C****overage Model**

- Quantitatively Explains Superfilling of Submicrometer Features

- Quantitative Model of “Brightening”

- Electrodeposition of Copper, Silver and Gold

- Chemical Vapor Deposition of Copper

**2. Transient Inhibition Breakdown Model**

- Explains Superfilling of Nickel and related Ni-Co-Fe alloys

## 10 m

- Catalyzed copper deposition
- on Au-S-(CH2)3-**SO****3****-**

- No copper deposition
- on Au-S-(CH2)3-**CH****3**

- 10 m

- The Important Role of Surface Chemistry:
- Competitive and co-adsorption of specific surfactants can lead to strong
- acceleration or inhibition of the metal deposition rate.

## Curvature Enhanced Accelerator Coverage Mechanism

- Dilute catalyst “floats” on the surface during metal deposition.
- Local catalyst coverage increases as local area decreases.
- Converse also true.
- Local metal deposition rate increases with catalyst coverage.

*CEAC is most important when changes in adsorbate coverage due *
*to area change dominates adsorption or consumption processes!!*

## Superfilling Trenches with Copper

- 70 s

- 50 s

- 40 s

- 30 s

- 25 s

- 35 s

- Copper deposition in an electrolyte containing    6 uM SPS 88 uM PEG 1mM NaCl

- CEAC Simulation and Experiment

## Ag and Au Superfilling using the CEAC Mechanism 

		Ag has a higher conductivity than Cu
		KSeCN catalyzed Ag electrodeposition

		Au is the metallization of choice in GaAs technology 
		Pb catalyzed Au electrodeposition

NIST offers measurements and metrology for understanding and optimizing superconformal electrodeposition of Cu, Ag and Au for use as conductors.

**	**
**	****	**Ag has a higher conductivity than Cu
- 		KSeCN catalyzed Ag electrodeposition
- 		Au is the metallization of choice in GaAs technology
- 		Pb catalyzed Au electrodeposition
- NIST offers measurements and metrology for understanding and optimizing superconformal electrodeposition of Cu, Ag and Au for use as conductors.

- 3-D metallization for ULSI and MEMS

## What about “active” magnetic materials?

- Applications of ferromagnetic materials (Ni, Co, Fe)
- 	- Magnetic recording heads and recording media
- 	- Magnetic sensors, actuators, motors for MEMS devices
- 	- Memory devices (MRAM, race track memories) and bio-medical systems
- However conventional fabrication of magnetic structures uses an inherently
-     2-D process (LIGA or “through-mask” electroplating) that is difficult to combine with CMOS for building 3-D structures.
- NIST has developed a deposition process that allows void-free filling of recessed features with nickel and related iron group alloys that can be easily integrated with existing  Damascene processes and related tool sets.

## Superfilling of Ferromagnetic Materials

- Damascene process for ferromagnetic structures

- 	- Easy to realize various 3-D magnetic structures
- 	- Suitable for integration with existing CMOS fabrication processes

## Collaboration Opportunities

- NIST has developed a wide range of measurements and modeling capabilities for exploring and optimizing superfilling processes.
- Intellectual Property:
- “Superconformal Electrodeposition of Ni-Fe-Co Magnetic Alloys”
- 	Provisional Patent Application filed 1/25/2008
- 	Serial # 61/023,593
- “Superconformal Metal Deposition Using Derivatized Substrates”
- 	 Provisional Patent Application filed 5/23/2003
- 	 Serial # 10/444,060

## For further information please contact:

			Thomas P. Moffat
			Materials Science and Engineering Laboratory
			National Institute of Standards and Technology
			Bldg 224, B166
			Mail Stop 8551
			Gaithersburg, Md 20899 

			thomas.moffat@nist.gov

- 			Thomas P. Moffat
- 			Materials Science and Engineering Laboratory
- 			National Institute of Standards and Technology
- 			Bldg 224, B166
- 			Mail Stop 8551
- 			Gaithersburg, Md 20899
- 			_[thomas.moffat@nist.gov](mailto:thomas.moffat@nist.gov)_