Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE

More documents

Recommendations

Info

SIWIS Département fédéral de l’environnement, des transports, de l’énergie et de la communication DETEC Office fédéral de l’énergie OFEN ULTRA THIN SILICON WAFER CUTTING BY MULTI-WIRE SAWING Annual Report 2007 Author and Co-Authors A. Bidiville, K. Wasmer, P. M. Nasch, M. Van der Meer, C. Ballif, J. Michler Institution / Company Empa – Materials Science and Technology Address Feuerwerkerstr. 39, CH-3602 Thun, Switzerland Telephone, E-mail, Homepage +41 (0) 33 228 29 71, kilian.wasmer@empa.ch, johann.michler@empa.ch, http://www.empathun.ch/ Project- / Contract Number CTI Nº 7730.2 NMPP-NM Duration of the Project (from – to) 01.12.05 – 30.11.07 Date 13.12.2007 ABSTRACT The objectives of the SIWIS project are to understand and to control the surface defect generation mechanisms governing the yield in multi-wire sawing of silicon wafers. The development activities of the project focus on analysing and characterising surfaces of sawn wafers and to develop models to predict surface damage during free wire sawing. The main motivation behind this project is to develop a multi-wire-sawing process technology that allows mass production of thin crystalline silicon wafer (
Seite 62 von 288 Introduction / project goals Silicon wafering for the PV industry is made by multi-wire slurry saw (MWSS).The cost of solar cells is mainly driven by the cost of silicon raw materials. One way to decrease these costs is to cut thinner wafers. The current wafer thickness in production is about 220 – 200 µm. This thickness is limited by the wafers strength due to the presence of sub-surface defects (SSD) introduced by the sawing process. The production of stronger wafers will not only allow to cut thinner wafers, but also to increase the wafers yield during subsequent production steps. The goal of this project is to understand the principle of MWSS and the influence of sawing parameters on wafers strength to finally be able to cut 120 µm thick wafers. In order to do this, a dual approach was chosen: in the one hand a more fundamental direction aiming at understanding the deformation process of silicon during contact loading and on the other hand a more applied direction aiming at understanding the influence of the sawing parameters on the SSD and on the wafers strength. Thus, the goals of the projects were: 1. To understand the deformation process of silicon during scratching and indentation 2. In-situ observation of deformation process, crack initiation and propagation during scratching and indentation. 3. To control the roughness of surfaces, and the initiation and propagation of microcracks during sawing. 4. To identify and understand the interaction of slurry flow, wire motion and rolling-indenting particles. 5. To understand and model the crack propagation with respect to the different length scale 6. Classification of the Sub-Surface Defects (SSD) with respect to MWSS parameters 7. Set-up a test bench to measure the mechanical fracture strength of sawn wafers Technical Summary In essence, a Mutli-Wire Slurry Saw (MWSS) consists of a wire being managed to constitute a multiwire web, allowing an abrasive liquid to penetrate an ingot driven through the web. More specifically, it consists of one 120-160 µm-diameter steel wire moving, either uni-directionally or bi-directionally, on the surface of the workpiece (e.g., a silicon ingot). The single wire is wound on wire-guides carefully grooved with constant pitch forming a horizontal net of parallel wires or web (Figure 1a). The wireguides are rotated by drives, causing the entire wire-web to move at a relatively high speed (10- 20m/s). A couple of high flow-rate nozzles are feeding the moving wires with an abrasive suspension (“slurry”) into the cutting zone. The workpiece (or the wire-web) is moved vertically. The wire tension is maintained constant (20-30 N) during the cutting process with state-of-the-art feedback control. A wire feed reel provides the length of a new wire and a wire take-up reel stores the used wire. In MWSS, material is removed by third-party free abrasive grains transported in a liquid media (slurry). The primary functions of the slurry are as follows: (i) carrying the abrasive particles to the cutting zone; (ii) flush away workpiece chips and residues (kerf); (iii) heat removal by the slurry liquid carrier. Most commonly used slurries are oil-based, water-soluble and water-based coolant, with generally SiC as abrasive. Upper Table Slurry Manifolds Inlet spool Take-up spool Ingots Wire web Lower Table Before Cut After Cut Figure 1: a) Schematic of a mutli-wire slurry saw, b) silicon wafer sawn, c) silicon wafer containing no defects SIWIS: Ultra Thin Silicon Wafer Sawing by Multi-Wire Sawing, A. Bidiville, Empa 2/6
Page 1:
Forschung, April 2008 Programm Phot
Page 4 and 5:
Programm Photovoltaik Ausgabe 2008
Page 6 and 7:
T. Meyer ORGAPVNET: Coordination Ac
Page 8 and 9:
PROGRAMM PHOTOVOLTAIK Eidgenössisc
Page 10 and 11:
1. Programmschwerpunkte und anvisie
Page 12 and 13:
Ein neues KTI-Projekt Flexible Phot
Page 14 and 15: In einem neuen, durch den Axpo Natu
Page 16 and 17: Performanz und Energieproduktion vo
Page 18 and 19: ERGÄNZENDE PROJEKTE UND STUDIEN En
Page 20 and 21: in diesem Projekt für die Koordina
Page 22 and 23: 5. Pilot- und Demonstrationsprojekt
Page 24 and 25: Produktionskapazität von insgesamt
Page 26 and 27: [26] H. Häberlin, L. Borgna, D. Gf
Page 28 and 29: [89] Konzept der Energieforschung d
Page 30 and 31: Solarzellen C. Ballif, J. Bailat, F
Page 32 and 33: Département fédéral de l’envir
Page 34 and 35: 3/9 Fig. 1: Refractive index n and
Page 36 and 37: 5/9 V oc [mV] 940 920 900 880 860 8
Page 38 and 39: 7/9 Fig. 5: Top) SEM micrographs of
Page 40: 9/9 Acknowledgements The co-workers
Page 43 and 44: Seite 40 von 288 Introduction and f
Page 45 and 46: Seite 42 von 288 Introduction / Pro
Page 47 and 48: Seite 44 von 288 Results The amorph
Page 49 and 50: Seite 46 von 288 Collaborations IMT
Page 53 and 54: Seite 50 von 288 High efficiency so
Page 55 and 56: Seite 52 von 288 Towards low costs
Page 58 and 59: Eidgenössisches Departement für U
Page 60 and 61: 3/6 The Athlet consortium comprises
Page 62 and 63: 5/6 Large area cluster deposition s
Page 66 and 67: 3/6 Results Defects characterizatio
Page 68 and 69: 5/6 The test methodology was optimi
Page 70: Département fédéral de l’envir
Page 73 and 74: Seite 70 von 288 Summary of Applied
Page 75 and 76: Seite 72 von 288 Table 5 summarizes
Page 78 and 79: Eidgenössisches Departement für U
Page 80 and 81: 3/7 Figure 1: Vacuum deposition equ
Page 82 and 83: 5/7 Testing of thickness, chemical
Page 84: 7/7 Figure 6: Large area flexible s
Page 89 and 90: Seite 86 von 288 Intensity / arb. u
Page 92 and 93: LARCIS Eidgenössisches Departement
Page 94 and 95: 3/6 Work and results Alternative Ba
Page 96 and 97: 5/6 As expected the addition of Na
Page 98 and 99: ATHLET Eidgenössisches Departement
Page 100 and 101: 3/9 ZnO:Al/ZnO was deposited by rf-
Page 102 and 103: 5/9 Figure 4: XRD pattern of powder
Page 104 and 105: 7/9 PBDVA temp [°C] 100 200 250 Bu
Page 106: 9/9 National and international coll
Page 109 and 110: Introduction / Project Goals Thin f
Page 111 and 112: Introduction The work to be reporte
Page 113 and 114: Ongoing Work and Results 2007 Dye d
Page 115 and 116:
International Cooperation Internati
Page 117 and 118:
Introduction Dye-sensitized solar c
Page 119 and 120:
Figure 2: Upper panel: isodensity p
Page 122 and 123:
Eidgenössisches Departement für U
Page 124:
3/3 (a) (b) I N ClO ClO4- 4- Al ITO
Page 127 and 128:
Seite 124 von 288 Project Goals The
Page 129 and 130:
Seite 126 von 288 Within the activi
Page 131 and 132:
Seite 128 von 288 Typical UV-Vis sp
Page 133 and 134:
Seite 130 von 288 National and inte
Page 135 and 136:
Project Goals The goal is the estab
Page 138 and 139:
NAPOLYDE Département fédéral de
Page 140 and 141:
3/7 � PECVD/Sputtering Co-deposit
Page 142 and 143:
5/7 Work and results SP2.4 - Nanola
Page 144:
7/7 Evaluation 2007 and Outlook 200
Page 147 and 148:
Projektziele In der Schweiz bestehe
Page 149 and 150:
Die wichtigsten erreichten Ziele de
Page 151 and 152:
Energy Center (EC) der EPFL Univers
Page 153 and 154:
Für 2008 ist in Zusammenarbeit mit
Page 156 and 157:
BIPV-CIS Eidgenössisches Departeme
Page 158:
3/3 Bewertung 2007 und Ausblick 200
Page 162 and 163:
Département fédéral de l’envir
Page 164 and 165:
3/9 Service measurements In 2007 a
Page 166 and 167:
5/9 Type of meas. Direct with c-Si
Page 168 and 169:
7/9 c-Si reference cell for the mea
Page 170:
9/9 � 4 energy rating comparison
Page 173 and 174:
1. Traceable performance measuremen
Page 175 and 176:
The following list shows the measur
Page 177 and 178:
data sets. The indoor data sets con
Page 179 and 180:
The blind round-robin proved that o
Page 181 and 182:
Einleitung / Projektziele Herstelle
Page 183 and 184:
Abb. 1, und deren Mittelwert für d
Page 185 and 186:
Aus Gleichung (1) ergeben sich der
Page 187 and 188:
Abb. 7: Abhängigkeit des Wirkungsg
Page 189 and 190:
Der Rechengang zu Abb.8 läuft wie
Page 191 and 192:
Wie erwartet ist der Jahresmittelwe
Page 193 and 194:
Projektziele für 2007 � Ununterb
Page 195 and 196:
Generator-Korrekturfaktor k G in %
Page 197 and 198:
WR-Defekte pro WR-Betriebsjahr 0.8
Page 199 and 200:
Nationale / internationale Zusammen
Page 201 and 202:
Einleitung / Projektziele Dezentral
Page 203 and 204:
BON: Betrieb ohne Netz oder USV-Bet
Page 205 and 206:
An einem Workshop mit EWs in Kalifo
Page 207 and 208:
Page 209 and 210:
Challenges The liberalisation of th
Page 211 and 212:
W 900 800 700 600 500 400 300 200 1
Page 214 and 215:
PV-BUK Eidgenössisches Departement
Page 216 and 217:
3/6 häufigsten traten jedoch Gesam
Page 218 and 219:
5/6 Die Gespräche mit verschiedene
Page 220 and 221:
Page 222 and 223:
3/10 Tab. 1: Overview of the types
Page 224 and 225:
5/10 Tab. 2: Key parameters of the
Page 226 and 227:
7/10 horizontal surface (kWh/m 2 )
Page 228 and 229:
9/10 6. Conclusion and Outlook The
Page 230 and 231:
Page 232 and 233:
3/9 Fig.2: Photograph of SiO2:CdS s
Page 234 and 235:
5/9 Fig. 4: Photoluminescence spect
Page 236 and 237:
7/9 In general, the performance of
Page 238:
9/9 Conclusions � A large Stokes
Page 241 and 242:
Einleitung / Projektziele Solaranla
Page 244:
Internationale Koordination P. Hüs
Page 247 and 248:
Kurzbeschrieb des Projekts Task 1 u
Page 249 and 250:
Trends Report Basierend auf den Dat
Page 251 and 252:
Page 253 and 254:
Einleitung / Projektziele Die Ziele
Page 255 and 256:
Case Studies Als Ergänzung zu den
Page 258 and 259:
Page 260 and 261:
3/10 Ziele 2007 Die Ziele der REPIC
Page 262 and 263:
5/10 Die restlichen 13 Projektantr
Page 264 and 265:
7/10 Stand der technischen REPIC Pr
Page 266 and 267:
9/10 Förderung der Solarenergie f
Page 268 and 269:
Département fédéral de l’envir
Page 270 and 271:
3/6 Les avantages pour le consommat
Page 272 and 273:
5/6 SOUS-TÂCHE 4 « Information et
Page 274 and 275:
Page 276:
3/3 Turbidity climatology Turbidity
Page 279 and 280:
Einleitung / Projektziele Normenarb
Page 281 and 282:
IEC 62548 Installation and Safety R
Page 283 and 284:
Referenzen Eine vollständige Liste
Page 285 and 286:
Introduction and Goals PV ERA NET i
Page 287 and 288:
WP2: Strategy Issues: The main acti
Page 289 and 290:
A dedicated transnational call “P
Page 291:
Databases have been developed for o
show all

Programm Photovoltaik Ausgabe 2008 ... - Bundesamt für Energie BFE

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?