High Purity Water Needs for the PV Industry Part 1: Development of Cost Effective Specification

Size: px

Start display at page:

Download "High Purity Water Needs for the PV Industry Part 1: Development of Cost Effective Specification"

Todd Shelton
5 years ago
Views:

1 High Purity Water Needs for the PV Industry Part 1: Development of Cost Effective Specification John Morgan Sarah Schoen, Andreas Neuber, Marty Burkhart, John Morgan, and Slava Libman SEMI PV Task Force Water WG

2 PV Challenges Profitability Growth High Productivity Low production cost High yield High Efficiency Increasing complexity Increasing quality requirements

3 Historical Trend of Semi UPW Quality Requirements vs. System Complexity Year UPW Quality 20 UPWSystem Capability PresentTime 12 Future??? Avanced Oxidation Final Filter (UF or MF) 10 UV (Polish 185) IX (Polish) 15 SemiUPW Quality Requirements 8 HX for Fine Temp control UV (Ozone Destruct,254) Tank Ozonation Ion exchange UV (Make UP, 185) 10 6 Reverse Osmosis Cartridge Filter HX for Temp control 4 Multi Media Semi UPW Quality Requirements 5 UPW Equipment Quality Capability 2 PV UPW Quality Requirements 0 DI Water RO/DI UPW Ultra UPW Future UPW 0 PV UPW Quality Requirements

Case study: wise cost optimization Cost drives use of lower cost components Material compatibility and proper implementation are important Side

4 Case study: wise cost optimization Cost drives use of lower cost components Material compatibility and proper implementation are important Side effects may impact production resulting in impacts to productivity and cost Courtesy of ASU: particle excursion resulted from use of clean PVC in HPW

5 SEMI PV Gas and Chemical Purity TaskForce Members WaterTeam Name Company Team Last First Water Burkhart Marty Hi Pure Tech, Inc. Roy Biswanath Pall Libman Slava MW Zander Hackett Tom KMG Electronic Chemicals Cook Don Cook Engineering Monitor Williamson Casey Semtec McIntosh Bob SolarWorld Bennett Mike Evergreen Engineering Cohen Ralph Ralph M Cohen Consultancy rmoc999@msn.com Krygier Vivien Pall Vivien_Krygier@pall.com Schoen Sarah Balazs Sarah.Schoen@Balazs.com Kingsford Kenji Parker kkingsford@parker.com Staehle Rick UnivarUSA Rick.Staehle@univarusa.com Szilvas Wolfgang First Solar wszilvas@firstsolar.com Bhatia Kamal (Kam) PV Independent Consultant kambhatia@sbcglobal.net Morgan John H2Morgan Engineering john.morgan@h2morgan.com

6 Risk Management by Standardization Lack of technical information and standards requires ongoing risk management. Larger PV cell manufacturers have developed proprietary in-house standards. New players look to third party equipment suppliers in order to build a complete production line. This approach can only succeed if industry standards are agreed upon for the interfaces that are used by these systems. In contrast with numerous ultrapure water (UPW) standards for semiconductor industry, no HPW for PV water quality standard exists.

7 Methodology Learning from history of Semiconductor UPW spec development Industry survey Technology benchmarking survey F063 (Semiconductor spec) platform Literature survey and direct communication with the PV industry experts

8 The survey results Most systems had a continuous recirculation distribution system (not a dead-end); Despite expected and reported low sensitivity to TOC, some systems employed ozonation; Although a relatively low Resistivity requirement was expected, most of the systems had mixed beds (ion exchangers); Even membrane degasifiers were reported ; Tight particle control was required, since most of the systems used either microfiltration or ultrafiltration as last treatment process step. The whole spectrum of the piping materials is used (PVC, CPVC, PP, SS, PVDF, and PFA), probably indicating that some of the system might have had a history of semiconductor manufacturing in it; The participants reported a wide range of the capacity of the systems, from small < 50 gpm to large >300 gpm.

9 The survey results, cont. Relatively high (higher than expected) Resistivity (>17.5); Low sensitivity to dissolved organics; Some required relatively tight specs for bacteria and particles; Requirements for total and reactive silica were much less stringent than ITRS [4]; Some indicated sensitivity to metals: Fe, Cu, and Al were reported more often. However even for those the spec was orders of magnitude high than similar semiconductor specs [4]; For the anions: sulfate, nitrite, and chloride were reported often; As expected, dissolved oxygen and temperature control were not required in most of the cases.

10 Typical Configuration of HPW systems UPW Quality Level A Level B Level C Level D Ultra-high purity High Purity High Quality Standard Pretreatment (~1 MΩ cm) RO, RO-RO; IX-RO; RO, IX; RO- RO; IX-RO RO; RO-RO; IX-RO IX; RO, RO- RO; IX-RO Make-up UV- MB; or UV-CEDI-MB, UV-EDI- UV- MB; or UV-CEDI-MB Polish (O3)-UV-MB- UF UV-MB- MF (0.05 μm) MB-MF(0.1 or 0.2 μm), or CEDI-MB- MF (0.1 or 0.2 μm) AB-CB- MF(0.2 μm); or CEDI MF(0.2 μm) Distribution material Supply PVDF PVDF, PP PP, PVC PP, PVC Return PP PP, PVC PP, PVC PP, PVC

11 Typical Water Quality UPW Quality Level A Level B Level C Level D Ultra-high purity High Purity High Quality Standard Re, MΩ cm >18.2 >18.2 >17 >10 TOC, ppb < 1 < 5 <20 < 100 Critical metals, ppb <0.01 < 0.05 < 0.1 < 0.5 Particles, #/L Size of the critical particle, μm < < 3, < 10, < 10, Bacteria, #/L 0 (excl. sample contamination) 0 (excl. sample contamination) Total Si, ppb B, ppb NA NA NA NA DO, ppb NA NA NA NA

12 Other findings Particles and resulting pinholes are considered critical only when visible from about 0.5 m (any material); Metal particles and ions are the only contamination sources which had an observed impact on efficiency and yield; Not all metals are critical (high diffusion rate and must cause crystal effects). Mainly three metals are considered critical: Fe, Cu, Au. Specs in the material are in the ppm range. In the future UPW quality will become more important for high efficiency processes on one hand because the raw material becomes cleaner and on the other hand processes are introduced such as plating instead of screen printing which are more contamination sensitive.

13 PV HPW specification PARAMETER RANGE OF PERFORMANCE JUSTIFICATION Resistivity 25 C (Mohm cm) High Purity >17.5 >10 Standard Purity Plant operation TOC on-line (ppb) <20 <200 None for PV / Experience from Semiconductor Dissolved Oxygen on-line (ppb) NA NA On-line Particles/L (micron range) <1000 NA Real problem are metal particles <100 <10, <10 <1000 >0.5 <1 <100 Pinholes Bacteria (CFU/L) <10 <100 Equipment operation

14 PV HPW specification, cont. PARAMETER RANGE OF PERFORMANCE High Purity Standard Purity JUSTIFICATION Silica Silica total (ppb as SiO2) <20 <50 Plant operation Silica dissolved (ppb as <20 <50 SiO 2 ) Note 1 Ions & Metals (ppb) Ammonium, Bromide, Chloride, Fluoride, Nitrate, Nitrite, Phosphate, Sulfate <1 <10 Plant operation None reported Antimony, Arsenic <1 <10 experience from semiconductor

15 PV HPW specification, cont. PARAMETER RANGE OF PERFORMANCE High Purity Standard Purity JUSTIFICATION Copper <1 <10 Relevant for performance Gold <1 <10 Relevant for performance (NEW) Iron <1 <10 Relevant for performance Lead, Aluminum, Cadmium, Manganese, Nickel, Chromium, Tin, Titanium, Vanadium, Zinc <1 <10 Not clear, to be studied Lithium, Sodium, Potassium <1 <10 Not clear, to be studied Magnesium Calcium Barium <1 <10 Not clear, to be studied

16 Process Control Achieve Water Quality Stability at the POD Establish a baseline to determine levels that give current yields. Compile meaningful data by establishing a sampling schedule, documenting normal levels and variation, and monitoring trends over time. Monitor causes of fluctuations such as Feed water quality (especially seasonal changes), internal operational activities, component change outs, regenerations, RO cleanings, and system modifications such as distribution piping additions/reductions, valves, and pumps. Communicate baseline data and changes in water quality back to the process engineers. This will aid in tying water quality to changes in yield (or in vindicating the water system during a yield loss).

17 Summary Lower cost require proper engineering Semiconductor experience provides good reference and technology tools SEMI Task Force conducted survey and proposed specification that should support the industry needs Process control is essential for ongoing risk mitigation

18 Back-up