Etching Media for Oxidic, Transparent, Conductive Layers

• US 20080217576A1
• Filed: 07/03/2006
• Published: 09/11/2008
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Original Assignee: Merck Patent GmbH (Merck & Co., Inc.)
• Inventors: Stockum, Werner, Kuebelbeck, Armin
• Granted Patent: US 7,824,563 B2
• Time in Patent Office: Days
• US Class Current: 252/79.2
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C09K 13/04 containing an inorganic acid
• CPC Class Codes: C09K 13/06 with organic material
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 59/80517 Multilayers, e.g. transparent multilayers
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

The present invention relates to a novel etching medium for the structuring of transparent, conductive layers, as are used, for example, in the production of liquid-crystal displays (LCDS) using flat-panel screens or of organic light-emitting displays (OLEDs) or in thin-film solar cells. Specifically, it relates to particle-free compositions by means of which fine structures can be etched selectively in oxidic, transparent and conductive layers without damaging or attacking adjacent areas. The novel liquid etching medium can advantageously be applied by means of printing processes to the oxidic, transparent, conductive layers to be structured. Subsequent heat treatment accelerates or initiates the etching process.

Claims

1. Etching medium for the etching of oxidic, transparent, conductive layers, comprising an at least one etchant consisting of

phosphoric acid or salts thereof or

adducts of phosphoric acid or

mixtures of phosphoric acid with salts of phosphoric acid and/or adducts of phosphoric acids.

2. Etching medium according to claim 1, comprising, as active component, ortho-, meta-, pyro-, oligo- and/or polyphosphoric acid and/or meta-phosphorus pentoxide, or mixtures thereof.

3. Etching medium according to claim 2, comprising one or more different ammonium salt(s) of phosphoric acid and/or mono- or di- or triesters of a phosphoric acid which liberate the etching phosphoric acid through thermal input of energy.

4. Etching medium according to claim 1 in paste form, comprising, in addition to at least one etchant, solvents, particulate and/or soluble inorganic and/or organic thickeners and optionally additives, such as antifoams, thixotropic agents, flow-control agents, deaerators and adhesion promoters.

5. Process for the etching of oxidic, transparent, conductive layers, characterised in that an etching medium according to claim 1 is applied by means of a printing process to the substrate to be etched.

6. Process according to claim 5, characterised in that said etching medium a is applied, depending on the consistency, by spraying, spin coating, dipping or by screen, stencil, stamp, pad or ink-jet printing.

7. Process according to claim 5, characterised in that the heating is carried out on a hotplate, in a convection oven, by IR radiation, visible light, UV radiation or microwaves.

8. Process according to claim 5 for the structuring of oxidic, transparent, conductive layers for the production of solar cells.

9. Process according to claim 5 for the structuring of oxidic, transparent, conductive layers for the production of flat-panel screens.