1. Ultrasonic Coating Systems for Solar Cell Manufacturing
Insert real pic of Hypersonic

2. Our History
Sono-Tek Corporation was founded in 1975 by Dr. Harvey L. Berger, Ph.D. Inventor of the ultrasonic nozzle
The first ultrasonic nozzles were developed for use in oil burners and subsequently for the development of liquid fuel burners contracted by the U.S. Military for use in portable power generation equipment.
Today Sono-Tek offers a wide selection of precision ultrasonic coating systems across various industries including Energy, Defense, Semiconductor, Aerospace, Medical Devices, Glass Manufacturing, and Textiles.

3. Common Stock Sono-Tek became a publicly traded company in 1987.
The Company’s Common Stock trades in the over-the-counter market on the OTC Bulletin Board under the symbol SOTK.

4. Corporate Headquarters
Sono-Tek’s corporate headquarters is located in Milton, NY, USA. This facility houses our factory as well as a full staff, including our engineering, sales, accounting, manufacturing, quality control, technical support and shipping departments.
Sono-Tek has a satellite office in Hong Kong to facilitate sales and service to our Asian customers. We also have laboratory testing facilities located in the U.S., Germany, Honk Kong, Korea,
and Taiwan.

5. Ultrasonic Atomization
When liquid is added to a resonating nozzle, waves are formed on the atomizing surface
SONO-MATH 101:
λL=((8*π*θ)/(ρ*f2))1/3
π = pi
θ = Surface Tension
ρ =Density
F = Frequency of Nozzle
Increasing the power causes the wave peaks to get so high that droplets fall off the tips of the wave.
These droplets have a mathematically definable size.
SONO-MATH 101:
DN, 0.5=.34*λL
Notice also that less of the atomizing surface is used (for a given flow rate).

6. Industry Expertise
SOLAR CELL
FUEL CELL
ELECTRONICS
MEDICAL

7. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

8. Thin Film Solar Cells Typical Layering of a Thin Film Cell
Cells may be comprised of some or all of the following layers, this is a typical cell in a substrate configuration.
GLASS/PROTECTIVE LAYER
ANTI-REFLECTION LAYER
TCO
Buffer Layer / PEDOT (OSC)
ACTIVE LAYER
BACK CONTACT
Sono-Tek can coat these layers

9. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

10. Thin Film Solar Cells Active Layer
The active layer creates the positive side of the p-n junction and creates a potential in the thin film structure. It contains semiconducting materials which may be one of the following:
CIS
Thickness ~ 1.5 – 4.5 microns
CIGS
Thickness ~ microns
CdTe
Thickness ~ microns
CTZS(S)
DSC Thickness ~ 1 – 3 microns
Quantum Dots
Nano-crystal semiconducting dots contain Zn, Pb, Cd, Se
Perovskites
Thickness ~ 50nm – 1 micron
GLASS/PROTECTIVE LAYER
ANTI-REFLECTION LAYER
TCO
ACTIVE LAYER
BACK CONTACT
Buffer Layer / PEDOT (OSC)

11. Active Layer Coating Equipment Low to High Volume Solutions
R&D
Low to Mid Volume Production
High Volume Production

12. Thin Film Solar Cells Active Layer
Alternate deposition methods:
CVD, Sputtering
Extremely expensive, high initial capital cost
Batch processing (trending toward inline with new systems)
In many cases low transfer efficiency – as low as 50%

13. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

14. Thin Film Solar Cells Buffer Layer / Use of Polymers
CIGS, CDTE, Cells
Common Buffer Layer
CdS - Thickness ~ microns
ZnS – Thickness ~ microns
Organic Cells, Perovskite
Typical Polymers - PCBM, P3HT, P3HD
PEDOT layer is commonly used with active layers made of polymers, and acts as an anode, and is currently used in R&D applications
Polymers are often sprayed in inert environment
Requires very low oxygen levels(<2 ppm)
Thickness (~ 0.11 – 0.17 microns)
Temperature ~ ºC
Annealed at low temperatures (150 – 250ºC)
Mixed with solvents
Chlorobenzene
P-Xylene
GLASS/PROTECTIVE LAYER
ANTI-REFLECTION LAYER
TCO
ACTIVE LAYER
BACK CONTACT
Buffer Layer / PEDOT (OSC)

15. Thin Film Solar Cells DSC Organic Solar Cells Layers
TCO layers can be created with ultrasonic spray pyrolysis.
Cathode layer – Platinum is most efficient but high $$, graphite less expensive and less efficient.
Electrolyte – usually applied in gel form. Needs to be diluted to be sprayed with ultrasonics.
Dye – Usually dip coated but can be applied with ultrasonic spray.
Compact oxide can be sprayed with ultrasonics, then heated.
Glass is often purchased with TCO layer already applied.

16. Thin Film Solar Cells Perovskite Solar Cells Layers
Sono-Tek ultrasonic nozzles can be used to spray the following layers:
TCO (CNT, Graphene, Silver Nanowires, ITO & FTO through spray pyrolysis.
Perovskite materials.
HTM (PEDOT: PSS, P3HT)
Nano-Metals (Nano-Gold, Silver Nanowires)

17. Thin Film Solar Cells ExactaCoat Inert
Commonly used for Organic Solar Cell Manufacturing
Built for continuous operation with constant positive pressure environment using Nitrogen, Argon or Helium
<1 ppm H2O and O2 inert gas
Continuous recirculation and on-line monitoring of O2 and moisture content
Hepa gas flow filters at chamber inlet and outlet
36” D x 48” W x 36” H chamber
Large antechamber - 38 cm (15”) OD and mini antechamber - 15 cm (6”) OD
400 mm x 400 mm x 100 mm
(15.75” x 15.75” x 3.94”) XYZ range of motion
Includes Windows®-based (programming) software with image import
Nozzles can be easily interchanged to produce varying spray patterns ranging from 0.080” to 3” ( mm) wide

18. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

19. Thin Film Solar Cells – TCO/Contact Grid
TCO (Transparent Conductive Oxide) consists of metals dissolved in solution having high conductive and transparent properties. It acts as the front contact to the device and is needed to reduce the series resistance of the device. Sometimes applied at high temperatures in pyrolysis reaction. Also, they often require high temperature annealing at 500 – 600 degrees C.
ITO
Can increase conductivity of ITO in 2 ways:
Increasing heat - Increasing the temperature of the substrate during the coating process has indicated an increase in conductivity
Increasing thickness of ITO layer (~ 0.04 microns)
Problems:
As thickness increases, cracking is more susceptible
ZnO (~ microns)
Doped with Ga, Al, In
Structure and morphological properties same for Ga, Al and In
Optical properties much better for In (smoother) than for Ga or Al
ZnO has the highest piezoactivity compared to other TCO’s
CdO
Doped with In, Sn, F
F is preferred because of low cost and is less hazardous
SnO2 (Commonly SnO2 :F or FTO)
Has higher efficiency than ITO
(SnO2 ~ 2 X’s efficiency than ITO)
GLASS/PROTECTIVE LAYER
ANTI-REFLECTION LAYER
TCO
ACTIVE LAYER
BACK CONTACT
Buffer Layer / PEDOT (OSC)

20. Spray Pyrolysis Applications
Definition of Spray Prolysis - A process in which thin film is deposited by spraying solution onto a heated surface, where constituents react to form a chemical compound
One Major Glass Manufacturer – 6 million m2/yr – doing spray pyrolysis on float glass line. 600 – 700 degrees C.
ExactaCoat for TCO – Duplicates this process on a smaller scale. Can be scaled up to much larger process, i.e. float glass line.

21. Thin Film Solar Cells ExactaCoat for TCO R&D System
Fully Enclosed XYZ Motion System for Ultrasonic Spray Pyrolysis, depositing TCO layers in R&D scale spray applications.
Precise substrate uniformity with repeatability down to +/-2%
Compact benchtop design that favors portability
400 mm x 400 mm x 100 mm (15.75” x 15.75” x 3.94”) range of motion
PathMaster® Windows®-based programming software
Remote trackball teach pendant
Coordinated motion in all three axes simultaneously
Optional 250oC heat plate or 600oC ready with customer’s plate
Cooling of ultrasonic nozzle
Protective bellows and covers over XYZ slides and motors
Cooling of XYZ motors
Teflon coated wetted surfaces
Cobalt A12 Series corrosive resistant nozzle (typical)

22. Thin Film Solar Cells Impact ARRAY Production Volume TCO System
Inline Ultrasonic Spray Pyrolysis System
Inline spray system with Cobalt A12 Series corrosive resistant nozzles.
Proprietary materials of construction protect wetted paths from TCO acid solutions.
Ability to easily manipulate coating thickness.
Full process control with recipe storage through HMI touch screen PLC interface.
Integrated control of nozzle, liquid delivery flow rate and deposition for a full coating solution.
Non-clogging ultrasonic nozzles produce repeatable, controllable, uniform thin films.
Designed for integration into high volume manufacturing lines.
Cost effective alternative to sputtering or CVD.

23. Thin Film Solar Cell TCO Layers
Alternate deposition methods:
CVD, Sputtering
Extremely expensive, high initial capital cost
Batch processing (trending toward inline with new systems)
In many cases low transfer efficiency – as low as 50%

24. Thin Film Solar Cells CNT and AgNW as Future TCOs
Why CNT/AgNW would be a desirable material for TCO layer:
Ability to be processed at low temperature and ambient pressure
Low cost (for CNT)
Works well with polymer active layer
PEDOT
P3HT/PCBM
Advantages over ITO (Possible future replacement)
CNT are capable of being put into liquid solution for deposition
Abundant raw material
Highly flexible
Excellent stiction (adherence to substrate and reduced friction)
Visible in infrared range
Extremely high conductivity
GLASS/PROTECTIVE LAYER
ANTI-REFLECTION LAYER
TCO
ACTIVE LAYER
BACK CONTACT
Buffer Layer / PEDOT (OSC)

25. Thin Film Solar Cells CNT Deposition Advantages
Ultrasonic technology brings a large advantage in the deposition of CNT/AgNW due to the ability to deagglomerate/ break apart clumped solids.
Ultrasonic action of the nozzle deagglomerates CNT clumps during the spray process
CNTs agglomerated prior to ultrasonics
CNTs deagglomerated with ultrasonic spray

26. Thin Film Solar Cells Manufacturing Market Competition
Process
How it works
Disadvantages (to ultrasonic spray)
Cost
Sputtering
Ejecting particles from a target, by bombardment with high energy particles to a substrate in a straight line.
Very expensive, poor transfer efficiency, batch process, and is prone to contamination.
$$$$$
Chemical Vapor Deposition
Creates a reaction between various gasses over a substrate which condense on its surface creating a thin solid layer.
Expensive to scale up, very high operating expenses, and poor material usage.
$$$$$$
Screen Printing
Spreading a paste with a blade over a recessed substrate.
High load system, requires min viscosity, and poor uniformity on very thin coatings.
$$$$
Inkjet Printing
Operates in a similar fashion to home / office inkjet printer, ejecting tiny drops above a substrate.
Uneven surface contours, series of drops/uneven dispense, poor tolerance to abrasive chemicals, and high maintenance.
$$$
Spin Coating
Solution is placed on substrate and dispersed via a centrifugal force of spinning substrate.
Coating thickness is limited as is substrate size, batch process, and it cannot be patterned or scaled up. $$
Pressure Spray
Forces a liquid through a very small orifice to create small droplets.
High velocity creates bounce back and wastes material, poor turn down ratio, and large drops. Prone to clogging. $
Ultrasonic Spray
Drops are formed as a result of wave formation at the atomizing surface. Soft spray has little kinetic energy. Liquid is not constricted through the nozzle orifice.
ADVANTAGES: Tight drop distribution and non-clogging ultrasonics create very uniform thin films. Independent control of flow rate, drop size and deposition maximizes process efficiency and material usage.

27. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

28. SelectaFlux for Fluxing Solder Bus Lines
Fluxing and soldering of the solder bus is a crucial process as it ensures that the connections between the silicon crystal and the conductive electrical contacts are optimal for electricity to flow between them properly. This process is key to ensuring the modules’ quality and longevity.

29. SelectaFlux for Fluxing Solder Bus Lines
Used in Tabber Stringer Machines for fluxing the Solder Bus
SOLDER BUS LINES
Need to flux both sides of Solder Bus (top and bottom)
SOLDER CONNECTIONS TO BUS LINES
(NEGATIVE)
+ (POSITIVE)
Typical 2 or 3 Solder Bus lines per solar cell

30. SelectaFlux for Fluxing Solder Bus Lines
Ultrasonic Advantages:
Proven technology in high-volume solar cell manufacturing (100s of machines installed)
Ability to control flux thickness
Ultrasonic nozzles never clog
No overspray
Good edge definition
Only monthly maintenance
Simple adjustment of spray width from 2mm – 5mm by adjusting distance to solar cell
Non-contact fluxing method
Spray up and spray down configurations

31. SelectaFlux for Fluxing Solder Bus Lines
Fluxing pads (New method for fluxing solder bus lines)
7 m/sec line speed typical
Faster, cheaper method of solder bus fluxing
Flux deposition shown in green

32. SelectaFlux for Fluxing Solder Bus Lines
Fluxing Method Comparison:
Jetting technology
JETTING NOZZLE
Provides very small jets of flux ~ 0.5mm.
Spray is NOT atomized, causing excessively thick flux layer. This causes excess flux to be deposited beyond desired area.
High velocity jetting can result in satellite flux droplets.
ROLLER TECHNOLOGY
Roller technology
Contact application
Easily cracks cells
Excessive flux is applied
Roller is not accurate to apply a consistent quantity of flux.
Flux flows beyond desired area of coverage.
Contact method causes cracking/breaking
Conventional Air Atomization
High velocity spray results in high degree of satellite flux droplets.
ULTRASONIC NOZZLE
AIR ATOMIZATION NOZZLE
Both jetting and air atomization – highly susceptible to clogging
Excessive overspray can cause additional problems
Ultrasonic nozzle
Provides uniform, thin film coverage with small, atomized droplets
FLUXING AREA FOR A TYPICAL 1.5 – 3 MM SOLDER BUS
SOLAR CELL
Not capable of providing thin flux coatings.
Thin flux layer deposits only on desired area.

33. SelectaFlux for Fluxing Solder Bus Lines
System Components Include:
Power
Focus adjust air shroud
High speed solenoid valve
Bracket assembly with mounting holes
Ultrasonic Nozzle with button microbore
Flux reservoir w/level sensor and pressure relief valve
Control module houses Ultrasonic Generator, Electronics, timer, power supply, Idle/trigger power PCA

34. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

35. ChemCoat for Phosphoric / Boric Doping
Phosphoric or Boric acid doping is required to create the negative side of the P-N junction. The positive side is doped with boron. The P-N junction is responsible for creating a potential, through which freed electrons flow.
- Use real picture of hypersonic

36. N Type & P Type Doping Methods
Two Primary Methods Are Currently Used for N type Phosphoric Doping:
POCl3 Method – Bubbling nitrogen through a phosphoric solution inside of a chamber to create a vapor that covers everything, including the wafers.
Widely used and proven method
95% of wafers are doped using this method
Slow batch process with a long cycle time
Complex and expensive machinery
Coats both sides of the wafer
Inline Furnace Diffusion* – Uniformly spray coating solar cells with a phosphoric solution, then diffusing it into the cells using a high temperature oven.
Inline, continuous manufacturing process
Currently only 5% of the market
Several new companies offering complete products (BTU, Schmidt, Despatch) that include a spray coater and oven combination
* Industry trend is moving in this direction due to lower manufacturing costs
P Type Boric Acid doping is done with tube furnace BBr3 diffusion processes. ChemCoat offers a cost effective alternative to any of these doping methods.

37. ChemCoat for Phosphoric / Boric Doping
38” (965 mm) spray coverage with 5 independent wafer sensors
WideTrack stationary spray heads are proven for continuous wide area manufacturing lines
Enclosed internal spray area with clear PVC viewing windows, polypropylene skins
Fully integradable with high volume production lines
Touch screen HMI interface for system monitoring and recipe management
Drying gas for post-spray curing
Non-clogging uniform spray
Chemically resistant nozzle technology
Chemically inert, long life polypropylene conveyor
Zero maintenance, self-aligning, positive drive sprocket
Automatic integrated belt cleaning system
Intelligent spray controls allows selective coating width area for 1, 3 or 5 wafers across spray width
Pressurized electronics
Multi-level exhaust with monitoring
- Use real picture of hypersonic

38. Product Line for Solar Cell Manufacturing
Thin Film Solar Cells
Deposition of active layers
Deposition of buffer and/or organic layers
Deposition of TCO
Silicon Solar Cells
SelectaFlux - Fluxing of Solder Bus on Tabber/Stringer machines
ChemCoat – Phosphoric/Boric Doping
Solar Cell Packing
7. Anti-reflection Coatings

39. Anti-Reflection Coatings for Silicon and Thin Film (Primarily Silicon Today)
Helps reduce the reflection of desirable wavelengths from front glass of substrate and allows more light to reach the semiconductor film layer to operate more efficiently, more commonly used in Silicon applications.
Anti-reflection layers are commonly made of:
TiO2
SiO2
Increases cell efficiency by roughly 3 – 4%

40. Sono-Tek Ultrasonic Coating Systems
Installed in high-volume operations for solar cell manufacturers today

41. Sono-Tek’s corporate headquarters are located in Milton, NY USA, with additional offices in Hong Kong. Our extensive global support and distribution network provides factory trained personnel with local language support in dozens of countries worldwide.
Fin.
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