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

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.

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.

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.

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).

Industry Expertise SOLAR CELL FUEL CELL ELECTRONICS MEDICAL

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

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

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

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 ~ 1.5 - 4.5 microns CdTe Thickness ~ 2 - 5.5 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)

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

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%

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

Thin Film Solar Cells Buffer Layer / Use of Polymers CIGS, CDTE, Cells Common Buffer Layer CdS - Thickness ~ .02 - .05 microns ZnS – Thickness ~ .02 - .05 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 ~ 25 - 75ºC 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)

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.

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)

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” (2 - 76 mm) wide

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

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 (~ 0.2 - 0.5 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)

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.

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)

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.

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%

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)

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

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.

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

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.

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

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

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

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.

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

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

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

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.

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

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

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%

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

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. SOLAR08R9PPT