Thick-film pastes containing lead- and tellurium-oxides, and their use in the manufacture of semiconductor devices

• US 8,497,420 B2
• Filed: 05/04/2011
• Issued: 07/30/2013
• Est. Priority Date: 05/04/2010
• Status: Active Grant

• Current Assignee: Solar Paste LLC
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Carroll, Alan Frederick, Hang, Kenneth Warren, LAUGHLIN, BRIAN J., Mikeska, Kurt Richard, Torardi, Carmine, VerNooy, Paul Douglas
• Primary Examiner(s): Johnson, Jonathan
• Assistant Examiner(s): GOLDEN, ANDREW J
• Application Number:
  US13/100,533
• Publication Number:
  US 20110308595A1
• Time in Patent Office: 818 Days
• Field of Search: 136/256, 252/513, 257/741, 257/E23.01, 257/E21.159, 438/660
• US Class Current: 136/256
• CPC Class Codes: B22F 1/10 Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 1/105 containing inorganic lubricating or binding agents, e.g. metal salts
• CPC Class Codes: B22F 2007/047 non-pressurised baking of the paste or slurry containing metal powder
• CPC Class Codes: B22F 7/04 with one or more layers not made from powder, e.g. made from solid metal
• CPC Class Codes: B22F 7/08 with one or more parts not made from powder B22F7/062 takes precedence
• CPC Class Codes: C03C 3/122 containing oxides of As, Sb, Bi, Mo, W, V, Te as glass formers
• CPC Class Codes: C03C 3/142 containing lead
• CPC Class Codes: C03C 8/10 containing lead
• CPC Class Codes: C03C 8/12 containing titanium or zirconium
• CPC Class Codes: C04B 35/01 based on oxide ceramics
• CPC Class Codes: H01B 1/16 the conductive material comprising metals or alloys
• CPC Class Codes: H01B 1/22 the conductive material comprising metals or alloys
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/0264 Inorganic materials
• CPC Class Codes: H01L 31/1884 Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02E 10/52 PV systems with concentrators

Abstract

The present invention provides a thick-film paste for printing the front-side of a solar cell device having one or more insulating layers. The thick-film paste comprises an electrically conductive metal, and a lead-tellurium-oxide dispersed in an organic medium.

Claims

1. A thick-film paste composition for use in forming an electrical connection in a photovoltaic device comprising a semiconductor substrate having at least one insulating layer on a main surface thereof, the composition comprising:

a) 85 to 99.5% by weight of an electrically conductive metal or derivative thereof, based on total solids in the composition;

b) 0.5 to 15% by weight based on solids of a lead-tellurium-oxide, wherein the lead-tellurium-oxide comprises 30 to 65 mol % of lead oxide and 35 to 70 mol % of tellurium oxide; and

c) an organic medium;

wherein the thick-film paste, when fired, is capable of penetrating the at least one insulating layer.

2. The thick-film paste of claim 1, wherehi the electrically conductive metal comprises silver.

3. The thick-film paste of claim 1, wherein the organic medium comprises a polymer.

4. The thick-film paste of claim 3, wherein the organic medium further comprises one or more additives selected from the group consisting of solvents, stabilizers, surfactants, and thickeners.

5. The thick-film paste of claim 1, wherein the electrically conductive metal is 90-95 wt % of the solids.

6. The thick-film paste of claim 1, wherein the Pb—

Te—

O is at least partially crystalline.

7. The thick-film paste of claim 1, further comprising an additive selected from the group consisting of:

TiO₂, LiO₂, B₂O₃, PbF₂, SiO₂, Na₂O, K₂O, Cs₂O, Al₂O₃, MgO, CaO, SrO, BaO, V₂O₅, ZrO₂, MoO₃, Mn₂O₃, Ag₂O, ZnO, Ga₂O₃, GeO₂, In₂O₃, SnO₂, Sb₂O₃, Bi₂O₃, BiF₃, P₂O₅, CuO, NiO, Cr₂O₃, Fe₂O₃, CoO, Co₂O₃, and CeO₂.

8. The thick film paste of claim 1, wherein the lead-tellurium oxide further comprises one or more elements selected from the group consisting of:

Si, Sn, Li, Ti, Ag, Na, K, Rb, Cs, Ge, Ga, In, Ni, Zn, Ca, Mg, Sr, Ba, Se, Mo, 1N, Y, As, La, Nd, Co, Pr, Gd, Sm, Dy, Eu, Ho, Yb, Lu, Bi, Ta, V, Fe, Hf, Cr, Cd, Sb, Bi, F, Zr, Mn, P, Cu, Ce, and Nb.

9. A process comprising:

(a) providing a semiconductor substrate comprising one or more insulating films deposited onto at least one surface of a semiconductor substrate;

(b) applying a thick-film paste composition onto at least a portion of the insulating film to form a layered structure,

wherein the thick-film paste composition comprises;

i) 85 to 99.5% by weight of an electrically conductive metal or derivative thereof, based on total solids in the composition;

ii) 0.5 to 15% by weight based on solids of a lead-tellurium-oxide, wherein the lead-tellurium-oxide comprises 30 to 65 mol % of lead oxide and 35 to 70 mol % of tellurium oxide; and

iii) an organic medium; and

(c) firing the semiconductor substrate, one or more insulating films, and thick-film paste, forming an electrode in contact with the one or more insulating layers and in electrical contact with the semiconductor substrate.

10. The process of claim 9, wherein the thick-film paste composition is applied pattern-wise onto the insulating film.

11. The process of claim 9, wherein the firing is carried out in air or an oxygen-containing atmosphere.

12. An article comprising:

a) a semiconductor substrate;

b) one or more insulating layers on the semiconductor substrate; and

c) an electrode in contact with the one or more insulating layers and in electrical contact with the semiconductor substrate, the electrode comprising an electrically conductive metal and lead-tellurium-oxide wherein the lead-tellurium-oxide comprises 30 to 65 mol % of lead oxide and 35 to 70 mol % of tellurium oxide.

13. The article of claim 12, wherein the article is a semiconductor device.

14. The article of claim 13, wherein the semiconductor device is a solar cell.