(19) TZZ_Z¥7B_T (11) EP 1 503 967 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) Int Cl.: of the grant of the patent: C03C 17/34 (2006.01) C03C 17/36 (2006.01) 24.04.2013 Bulletin 2013/17 (86) International application number: (21) Application number: 03730196.7 PCT/EP2003/050144 (22) Date of filing: 06.05.2003 (87) International publication number: WO 2003/093185 (13.11.2003 Gazette 2003/46) (54) TRANSPARENT SUBSTRATE COMPRISING A CONDUCTIVE LAYER DURCHSICHTIGES SUBSTRAT MIT EINER LEITENDEN SCHICHT SUBSTRAT TRANSPARENT COMPRENANT UNE COUCHE CONDUCTRICE (84) Designated Contracting States: (56) References cited: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR EP-A- 0 507 236 EP-A1- 0 350 362 HU IE IT LI LU MC NL PT RO SE SI SK TR WO-A-01/09052 WO-A1-00/27771 WO-A1-01/28949 US-A- 3 655 545 (30) Priority: 06.05.2002 EP 02076779 US-A- 5 756 192 (43) Date of publication of application: • JAGER S ET AL: "Optical and electrical 09.02.2005 Bulletin 2005/06 properties of doped zinc oxide films prepared by ac reactive magnetron sputtering" JOURNAL OF (73) Proprietor: AGC Glass Europe NON-CRYSTALLINE SOLIDS, NORTH- HOLLAND 1170 Bruxelles (Watermael-Boitsfort) (BE) PHYSICS PUBLISHING. AMSTERDAM, NL, vol. 218, 1 September 1997 (1997-09-01), pages 74-80, (72) Inventor: HEVESI, Kadosa, XP004095556 ISSN: 0022-3093 cited in the GLAVERBEL - Centre R & D application B-6040 Jumet (BE) • JAGER S ET AL: "Optical and electrical properties of doped zinc oxide films prepared by (74) Representative: Bayot, Daisy et al ac reactive magnetron sputtering", JOURNAL OF AGC Glass Europe S.A. NON-CRYSTALLINE SOLIDS, NORTH- HOLLAND R&D Centre PHYSICS PUBLISHING. AMSTERDAM, NL, vol. Rue de l’Aurore, 2 218, 1 September 1997 (1997-09-01), pages 74-80, 6040 Jumet (BE) XP004095556, ISSN: 0022-3093, DOI: 10.1016/S0022-3093(97)00288-3 Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 1 503 967 B1 Printed by Jouve, 75001 PARIS (FR) 1 EP 1 503 967 B1 2 Description layers deposited in this manner have resistivities in the order of 3 or 4.10-4 ohm.cm. [0001] The present invention relates to a transparent These layers are not resistant to chemical attacks asso- substrate, in particular made of glass, covered with an ciated with ageing, nor attacks associated with a supple- arrangement of layers comprising at least one conductive 5 mentary process step such as might be necessary for transparent layer deposited by a vacuum process. The the deposition of an additional photovoltaic or electro- invention also relates to a process for the production of chromic layer. Moreover, these layers are not resistant such a covered substrate, its uses as electrodes and in to a thermal treatment such as tempering or bending. a heating glazing unit as well as the glazing obtained. When a substrate of glass covered with such a layer is [0002] To enable it to be used as heating glazing, in 10 subjected to a thermal treatment in air in the order of 500 particular in the automotive field, the substrate must be to 650°C, a degradation in conductivity has been ob- resistant to the tempering processes and mechanical de- served as well as the appearance of optical faults such formations necessary for shaping (bending) wind- as whitish specks etc. screens, rear lights, and other automobile windows. The [0008] Therefore, there is a need to have transparent temperatures reached during these treatments are in the 15 substrates, in particular of mineral glass, which are cov- order of 650°C, even up to 680°C. It is additionally im- ered with a conductive layer (serving as an electrode or portant that the covered substrate is properly weather- as a heating resistor coating) deposited by a vacuum proof, and the layered arrangement must be able to with- process and are resistant to thermal and chemical treat- stand exposure to the ambient atmosphere and to vari- ments. Advantageously, such layers have the lowest ous cleaning detergents as well as to mechanical stress- 20 possible electrical resistance while preserving the appro- es such as friction or scratching. priate optical properties (such as, for example, homoge- [0003] Use of a substrate covered with a conductive neous high light transmission (LT) (in particular higher layer functioning as an electrode is also known for the than 30%), low light reflection (LR)). production of, e.g., photovoltaic and electrochromic cells. [0009] Therefore, what is sought is a covering with a In the production processes of some of these products, 25 good conductivity while retaining a high light transmission the conductive layer is subjected to elevations in temper- (LT). For applications such as windscreens, LT values ature or chemical actions which can damage the conduc- higher than 70%, and even 75% are necessary. For ap- tive layer. Document US 5,512,107 describes solar cells plications such as vehicle rear windows, lower LT values using a zinc oxide-based conductive layer. The problem (to 30-35%, for example) are acceptable. For applica- of the stability of conductive layers at elevated tempera- 30 tions such as electrodes in a photovoltaic or electrochro- tures and in humidity is mentioned. In this document the mic cell, the highest possible LT values are sought conductive and photoactive layers are shaped in narrow ( >80%). strips. [0010] Since resistance is a function of resistivity ρ() [0004] Metal oxide-based semi-conductive layers for and thickness (e) of the conductive layer (R = p / e), the antistatic use intended for the prevention of the undesir- 35 temptation might be to greatly increase the thickness of able effects associated with the accumulation of electro- the conductive layer in order to reduce resistance. How- static charges are known. The conductivity of these lay- ever, for economic reasons and because of the light ers is low. Their sheet resistance reaches values in the transmission, the covering must retain reasonable thick- order of 105 ohm/square. (EP 229 509). nesses. [0005] Transparent conductive and low-emissive lay- 40 [0011] It has surprisingly been found that it is possible ers deposited by pyrolysis (liquid or vapour phase) such to obtain layers deposited by a vacuum process that re- as tin oxide doped with fluorine, SnO2:F, or doped with tain a low sheet resistance or decrease their sheet re- antimony, SnO2:Sb, are known. However, the conduc- sistance even after thermal and/or chemical treatment tivity of these layers is not adequate to render them ef- by applying at least one protective over-layer of metal fective as heating layer or as an electrode, since their 45 oxide, nitride or oxynitride. sheet resistance is generally higher than 60 Ω/h. [0012] The present invention relates to a transparent [0006] The deposition processes using pyrolysis pose substrate, in particular made of glass, covered with a the following disadvantages: poor production flexibility, stack of layers, said stack comprising the following prior they are in fact linked to a glass line production plant; the to thermal treatment: number of layers that may be deposited is more limited 50 than by the vacuum process; they do not allow as large a sub-layer selected from the oxides, nitrides and a diversity of materials to be deposited as with vacuum oxynitrides of titanium, aluminium, silicon, zinc, tin, processes. indium, molybdenum, bismuth, tantalum, cerium, [0007] Methods of depositing zinc oxide layers doped niobium, zirconium or tungsten, with Al or In (ZnO:Al or ZnO:In) by sputtering are known 55 at least one metal oxide-based conductive layer de- (B.Szyszka et al.: "Optical and electrical properties of posited by a vacuum process, in particular by mag- doped zinc oxide films prepared by ac reactive magnet- netron sputtering, having a thickness in the range of ron sputtering", J. of Non-Crystalline Solids 218). The between400 and 1100 nmand comprising zinc oxide 2 3 EP 1 503 967 B1 4 doped with one or more elements, in particular se- deposition. It has in fact been noted that it partially or lected from aluminium, fluorine, gallium, tin, indium, completely oxidises during annealing. and [0022] Any other protective layers capable of resisting at least one chemical or mechanical protective layer detergents, atmospheric conditions, exposure to partic- capable of maintaining a low sheet resistance or 5 ular chemical conditions (e.g. oxidising, reductive, acidic even decreasing the sheet resistance after thermal or basic environment) and/or mechanical degradation and/or chemical treatment, having a thickness in the could also be considered. range of between 20 and 180 nm, and as deposited [0023] The thickness of the protective layer is in the selected from the oxynitride and nitride of aluminium range of between 20 and 180 nm, preferably between 35 or from ZnSnOx. 10 and 100 nm. [0024] The layered stack comprises a sub-layer select- [0013] The term thermal treatment should be under- ed from the oxides, nitrides and oxynitrides of titanium, stood to mean any treatment of the tempering or bending aluminium, silicon, zinc, tin, indium, molybdenum, bis- type (in the order of 500-700°C), but also treatments in- muth, tantalum, cerium, niobium, zirconium or tungsten. volving temperatures in the order of 250 to 350°C.