Linde in Solar. - Linde Gas

Linde in Solar03An integral part of the PV manufacturingindustry.OthersOther materials(encapsulant junction box etc)Paste11%3%12%DepreciationLabour7%Labour &utilities16%33%Depreciation9%60%Processmaterials10%WaferGlass24%15%GasesCrystalline CostsThin Film CostsAlthough less than 25 different gases and chemicals are used in solarcellmanufacturing, in comparison with more than double that amountfor semiconductors, the volumes required are significantly greater andsupply chain management presents unique challenges. Amongst thedirect materials for thin film Si in particular, glass and gases togethercan account for about 40% of the cost of solar module production. Thuswhile a 100MW facility requires significant investment in infrastructureto ensure continuity of material supply, a 1GW facility requires theentire output of an industrial scale production facility for several of theprincipal materials.Delivering SafelyLinde has a strong track record in the safe manufacture, handling anddistribution of the specialist products needed for solar cell manufacture,as well as in the design and installation of the gas and chemical systemsnecessary for safe use. Linde has more than 10 years experience inboth the supply of bulk silane and the design and operation of on-sitefluorine generators, with more than 30 bulk silane and 25 fluorinesystems in use at customer sites worldwide.We work in partnership with our customers and contractors to ensureprojects are delivered safely. Our structured approach to risk mitigationincludes:- HAZOP (Hazard & Operability Studies) & Design Reviews- FMEA (Failure Mode Effects Analysis)- PSR (Project Safety Reviews)- Product stewardship / New Product Introduction ProcessLinde’s global footprint and well established culture of best practicetransfer is ideally suited as the PV industry sets up large scalemanufacturing in new geographies. For example, when Moser Baerconstructed the worlds first industrial scale thin film Si PV plant in India,Linde’s global PV experts teamed with colleagues at Linde’s large Indianoperation to ensure a world class project implementation and a smoothstart-up of this pioneering project.

÷=04 Linde in SolarOur mission is to develop and applyadvanced gas and chemical technologies.Linde’s mission is to develop and apply advanced gas and chemical technologies that help solar cellmanufacturers move toward grid parity, while encouraging the adoption of environmentally sustainablemanufacturing.Industry Goal($0.7 per watt)ManufacturingDriversStrategicLeversLindeTechnologyGas RecycleMaterial cost$ per m 2F 2CleanThroughput$ per wattSiH 4additiveEfficiencyW per m 2Wet ChemicalsYieldGas Purity

Linde in Solar05Thin Film Si technology is growing rapidly.OEM AOEM BOEM CBulk Gas(N 2& H 2)OthersOthers3% SiH 414%16%SiH 4Dopants21%31% Bulk41%Gases(N 2,Ar,H 2)39%31%3%39%SiH 425%NF 3TCOPrecursorsNF 337%Nextgeneration precursorsRelative proportions of process gases for 3 different equipment setsIn order to reduce the cost per watt, Linde has moved from ‘traditionalsupplier’ to becoming an integral part of the photovolaic industry.Linde’s people understand the critical manufacturing processes andare developing innovative gas and chemical technologies to lowerthe overall cost per watt. These cost reduction technologies will haveincreasing impact as the industry moves to ever larger manufacturingscale.The critical process step in all thin film silicon technologies is depositionof doped silicon film from a silane precursor in a Plasma EnhancedChemical Vapor Deposition (PECVD) system. The result is a thin film ofsilicon on the glass. Typically hydrogen is also introduced to controlthe kinetics of the film growth. Dopants are incorporated throughprecursors such as trimethyl boron (TMB), diborane (B 2 H 6 ), phosphine(PH 3 ) and methane (CH 4 ).This process also results in silicon deposition on other surfaces in theprocess chamber such as the showerhead and chamber walls, whichmust be periodically cleaned. Typically a fluorine-based etch processusing NF 3 , SF 6 or F 2 is employed for this purpose.Nitrogen is a critical utility in thin film Si fabs and is used for multipletasks including purging vacuum pumps and dilution of toxic orflammable gases in chamber exhaust lines for safety.Another important step is the deposition of a transparent conductiveoxide (TCO) film on the front glass. This is typically tin oxide or zincoxide deposited via sputtering or using an organometallic precursorsuch as diethyl zinc (DEZ).Gas cost reductions are possible by a variety of methods, such as:On site generation of bulk gasesThe economics of large scale fabrication plants favour on sitegeneration of major bulk gases such as hydrogen and nitrogen. Thiseliminates the transportation and delivery cost of cylinders andenhances security of supply.Lowering Cleaning CostsMore than 50% of the capital cost and over 40% of the direct materialscost is consumed in the PECVD processes that deposit the active siliconlayers. The PECVD chambers require frequent cleaning of silicon residue.Replacing current methods (NF 3 or SF 6 ) by fluorine (F 2 ) can improvecleaning economics by up to 40%. Fluorine is generated on-site usingpackaged fluorine generators.Increasing ThroughputBy utilizing fluorine based cleaning the throughput of the PECVD processmay be increased by up to 6% at no extra cost. Additives in silane mayincrease deposition rates and thereby increase throughput.Improving cell efficiencyThe cell efficiency is strongly affected by the composition of the activep-i-n layers in the amorphous and microcrystalline steps. The cellefficiency may be improved by controlling critical impurities in theprecursor gases.Linde’s PV technology development roadmap targets each of theseareas, and many more. In every case, Linde’s approach involvesclose collaboration with key members of the technology value chain,including suppliers, PV equipment manufacturers and customers. Thisclose integration with the industry and alignment of research anddevelopment goals with the primary objective of reducing cost per watthave been critical factors in convincing more than half of all thin film Simanufacturers globally that Linde is the gas partner of choice for them.

06 Linde in SolarSolar Thin Film Fabrication Plant Overview.On-site fluorinegenerationCompressed dryair systemsTurnkey engineering andon-site gas andchemical managementCylinder gasesHalocarbon 14OxygenDopants

Linde in Solar07Gas distribution andmonitoringGas cabinetsVMBsGas analysers and purifiersPipework systemsOn-site gas generationNitrogenHydrogenBulk liquified gasesNitrogenHydrogenArgonBulk compressed gasesHydrogenHeliumNitrogen trifluorideSilane

08 Linde in SolarThe industry continues to build capacityand make advances in crystalline silicon.Crystalline silicon solar cells are currently used in more than 80% of worldwide solar installations.Applications are primarily consumer based (on-grid) installations, but also provide a flexible means ofsupporting underdeveloped (off-grid) locations where grid power is unavailable. Crystalline silicon celloutput is expected to continue to grow at 20-30% year on year for the next several years.Silicon cost represents 60% of the overall c-Si cell manufacturing costs, although this is expected to declineas new global Si capacity comes on stream. The process materials component cost (7%) plays a critical rolein enabling higher cell efficiencies and lower production costs.Wafer Fabrication PlantHF/Nitric etch mixes pc-SiNaOH or KOH mc-Si + IPAHF/Nitric etch mixes pc-SiNaOH or KOH mc-Si & IPARaw MaterialProcessingPoly & MonoSi GrowthEtch & WashSawWash &SeparateWaferCrystalline Cell Critical Manufacturing StepsHF/Nitric etch mixes multi c-SiKOH+IPA or NaOH+IPA mono c-SiH 2 0 2 + HCl metallic removalPOCl 3 diffusionH 3 PO 4 mist + thermalEthanol + H 3 PO 4 mixO 3 /dilute HF (RENA)HF + hot airCF 4 /0 2 plasma etchHF or dilute HF etchHF +HNO 3 (multi c-Si)or YAG Laser at end of lineWafersWire Saw Damage& Texture EtchIon Doping& DiffusionPSGRemovalEdgeIsolationRemovalPre-ARCDepositionCleanPassivation& ARCLayer (SiN)BackReflectorContactMetalsCo-FiringFurnaceModuleAssemblyHCl + H 2 0HF + H 2 OSC1 clean (H 2 O 2 + NH 4 OH)SC2 clean (H 2 0 2 +HCl)SiH 4 /NH 3 /H 2 PECVDorN 2 Si PVD SputteringWet Chemistry Application ProcessGas Application Process

Linde in Solar09Linde provides a full product portfolio of high purity bulk and specialty gases as well as wet chemicalsfor c-Si cell processing. Linde has the experience and expertise to optimize such critical c-Si process stepsas etch/texturization, doping, PSG removal, edge isolation, anti-reflective coating (ARC) deposition, andvarious cleaning steps that are essential in c-Si cell performance.Screen printand dryerLaser edgeisolationOxide etchARC sputterdepositionDoping anddiffusion furnaceSaw damage andtexture etchTypical c-Si 50 MW Cell Fabrication LineCost reductionLinde has demonstrated capabilities and technologies to provide recycling and/or reuse of selectedwaste in-process chemistries. We work closely with PV cell manufacturers to develop specific systemsthat can reduce the expenses associated with chemical waste management, andenvironmental impact. Such systems enable further reductions in operational costs forour customers. One example of this is our KOH recycling capability which is detailed on page 15.

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Linde in Solar011Linde supplies the full range of gas andchemical products necessary for PVmanufacture †Typical gas and chemical requirements for thin film and crystalline Si manufacture. Exact requirements will vary depending on the process.Thin film SiProductSilane (SiH 4 )Nitrogen trifluoride (NF 3 ) *Fluorine (F 2 ) *Sulphur hexafluoride (SF 6 ) *Nitrogen (N 2 )Hydrogen (H 2 )Helium (He)Trimethlyboron (TMB) mixturesPhosphine (PH 3 ) mixturesDiborane (B 2 H 6 ) mixturesMethane (CH 4 )Argon (Ar)Oxygen (O 2 )Diethylzinc (DEZ)Disilane (Si 2 H 6 )Trichlorosilane (SiHCl 3 )Tetrachlorosilane (SiCl 4 )Typical GradeElectronicTechnicalElectronicTechnicalElectronicElectronicTechnicalElectronicElectronicElectronicTechnicalElectronicTechnicalElectronicElectronicSolar GradeSolar GradeTypical Package (200MW)ISO module (6000kg)ISO module (8000kg)On-site plantN/AOn-site plantOn-site plantPressure tank/Tuber trailer**CylinderCylinder bundleCylinderCylinderLiquid tankCylinder /Liquid tankDrum /Tank/ISO module(20,000kg)CylinderDrum/ISO module(10000-20000kg)Drum/ISO modulec-SiProductSilane (SiH 4 )Ammonia (NH 3 )Tetrafluoromethane (CF 4 )Nitrous Oxide (N 2 0)Nitrogen (N 2 )Oxygen (O 2 )Argon (Ar)Hydrogen (H 2 )Acetic Acid (CH 3 COOH)Ammonium Hydroxide (NH 4 OH)Buffered Oxide Etchants(NH 4 F:HF)Ethanol (C 2 H 5 OH)Hydrochloric acid (HCl)Hydrogen Peroxide (H 2 0 2 )Hydrofluoric acid (HF)Isopropyl alcohol (C 3 H 8 O)Potassium Hydroxide (KOH)Nitric acid (HNO 3 )Phosphoric acid (H 3 PO 4 )Sulfuric acid (H 2 SO 4 )Sodium Hydroxide (NaOH)Custom Product Mixes AvailableTypical GradeElectronicElectronicElectronicElectronicElectronicElectronicElectronicElectronic

12 ColumnLinde supplies the full range of gas andchemical products necessary for PVmanufactureBulk gasesLinde delivers secure and reliable supply of essential bulk gases, such as nitrogen, oxygen, argon,hydrogen and helium to both thin film Si and c-Si customers alike. These products are manufactured byour global network of high purity gas plants and delivered by road in liquid or compressed form to storagefacilities on the customer site. Linde offers a comprehensive design and installation service for bulk gassupply including storage tanks, evaporators, purifiers, filtration, and corresponding ultra-high puritydistribution systems. This ensures a safe and efficient operation with continuous product availability.On-site nitrogen & hydrogen generationFor large gas consumption, Linde’s ECOVAR systems offer a low cost, reliable solution for nitrogen, oxygen,hydrogen and compressed air. On-site supply systems are built around standardized components to ensuremaximum cost efficiencies, and can be designed for year round uninterrupted supply (8760 hours) throughincorporation of redundancy. Systems are automatically controlled, and are monitored by the nearest LindeGas facility to ensure a reliable gas supply.On-site fluorine generationLinde’s recommended alternative to global warming gases for chamber cleaning, fluorine (F 2 ), is alsogenerated on-demand on customer sites, utilising modular Generation-F ® systems that enable capacityscaling as PV plants ramp. High purity fluorine gas is the highest performance cleaning gas available,improving productivity on CVD tools, reducing energy consumption and environmental impact, with zeroGlobal Warming Potential. Linde has years of unrivalled experience in the safe and reliable generation anddelivery of fluorine, to the exacting specifications of the display and semiconductor industry. Systems areavailable to supply the cleaning gas needs of any size thin-film PV production fab, from 1 tonne to hundredsof tonnes per year.Special GasesLinde offers the full range of special gases to support photovoltaic manufacture. Linde operates a globalnetwork of 8 electronic special gas production plants strategically located in key markets, linked with 20+local stock locations by a state-of-the-art global logistics capability. Electronic special gases, includingsilane, NF 3 , ammonia and dopant mixtures, are shipped in a variety of container sizes depending onapplication, ranging from individual cylinders, to ISO containers.ChemicalsAUECC, a Linde Group company is a leading supplier of wet process chemicals to all high technologyindustries in Asia and beyond. Manufacturing is located in Shanghai, China and Taiwan. Linde provides afull range of acidic, alkaline, and organic process chemistries for monocrystalline and polycrystalline PVprocessing applications from silicon manufacturing through cell fabrication. Linde’s products support the PVwet process solutions for Saw Damage Repair, Surface Texturization, Surface Cleaning and PSG and EdgeIsolation Removal.

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14 Linde in SolarTurnkey engineering and on site gas and chemicalmanagement.Linde has installed hundreds of safe, efficient and robust gas systems within the global semiconductor,TFT-LCD, solar and LED industries. Linde’s expertise includes consulting, process design, turn-key projectmanagement, and commissioning.For on-going systems and materials management, Linde Electronics can offer full on-site gas and chemicalmanagement services, giving you full time access to in-depth gas and chemical know-how which ensuresa safe and smooth operation with minimised downtime and risk. Linde currently operates on-site teams atmore than 50 customer sites worldwide.

Linde in Solar15Facing environmental challenges and enablingsustainable manufacturing.A clear focus on environmentally sustainable manufacturing is a pillar of the Linde Group philosophy, andit is our goal to enable improvements in sustainability in every industry we serve. In the solar industry wecan provide real solutions to reduce your CO 2 footprint and recycle valuable consumables. In the area ofchamber cleaning for the very large area PECVD tools, gases like NF 3 , which are consumed in significantvolumes, have some of highest Global Warming Potentials (GWPs) measured. In the case of NF 3 , approx1,000kg of gas is consumed per MW of module manufacturing every year, regardless of technologyprovider. One of the highest priorities for Linde’s R&D programme in solar has been to pioneer technologiesto prevent these gases being released into the atmosphere – either through recycling or through alternativeapplications using environmentally less harmful gases.NF 3 replacementLinde has pioneered the use of molecular fluorine (F 2 ) as a replacement for NF 3 and SF 6 in PECVD chambercleaning. While NF 3 and SF 6 are high GWP gases, F 2 has zero global warming impact. Replacing NF 3 withFluorine in a 1GW thin film Si fab would result in elimination of NF 3 consumption with an untreated globalwarming potential equivalent to nearly 17 million tonnes of CO 2 per year. Linde’s proven technology forgenerating F 2 on-site and on-demand eliminates the need for large volume storage and addresses all thesafety requirements for handling this reactive material. In addition to its environmental benefit, F 2 reducesthe time for chamber cleaning, thereby increasing plant productivity, through a more efficient etchingprocess.KOH RecyclingThrough the Linde Group subsidiary, AUECC, based in Taiwan, Linde offers end to end recycling of wasteKOH for applications in mono-Si cell processing. Via a unique reprocessing technology, KOH recyclingyields product purity equal to, or even better than, original ‘fresh’ KOH quality. This innovative technologyis available on-site, anywhere in the world. Cost saving aspects include reduced waste neutralizationchemicals costs, reduced municipal waste effluent sewerage costs, reduced fresh purchases of potassiumhydroxide , reduced freight expenses for fresh KOH deliveries and reduced operator handling expenses.Overall estimated savings are between 20-30% compared with the continued purchase of fresh KOH.Technology developmentLinde, the leading supplier of gases, also takes leadership in solar PV research and development to drivedown the cost per watt in solar PV manufacturing. Linde has solar research and development locations inSan Marcos, California and in Europe with a joint development partner. Linde’s research and developmentefforts encompass both thin-film and crystalline silicon cell manufacturing. Areas of focus includedeveloping products and services that capitalise on efficiencies of scale, improve solar cell performance,optimise process and film parameters and develop new, novel materials that drive down costs.