THICK-FILM PASTES CONTAINING LEAD-TELLURIUM-BORON-OXIDES, AND THEIR USE IN THE MANUFACTURE OF SEMICONDUCTOR DEVICES

• US 20110232746A1
• Filed: 05/04/2011
• Published: 09/29/2011
• 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, Torardi, Carmine, Mikeska, Kurt Richard, Vernooy, Paul Douglas, Laughlin, Brian J.
• Granted Patent: US 8,895,843 B2
• Time in Patent Office: Days
• 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-boron-oxide dispersed in an organic medium.

Claims

1. A thick-film paste 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-boron-oxide; and

c) an organic medium.

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

3. The thick-film paste of claim 1, wherein the mole ratio of lead to tellurium of the lead-tellurium-boron-oxide is between 5/95 and 95/5.

4. The thick-film paste of claim 1, wherein the lead-tellurium-boron-oxide comprises:

25-75 wt % PbO,

10-70 wt % TeO₂,

0.1-15 wt % B₂O₃,

and 0-20.0 wt % of components selected from the group of PbF₂, SiO₂, Bi₂O₃, BiF₃, LiO₂, SnO₂, AgO₂, ZnO, V₂O₅, Al₂O₃, Na₂O, TiO₂, CuO, ZrO₂, and CeO₂.

5. The thick-film paste of claim 4, wherein the lead-tellurium-boron-oxide further comprises:

0.1-5 wt % TiO₂.

6. The thick-film paste of claim 5, wherein the organic medium further comprises one or more additives selected from the group consisting of solvents, stabilizers, surfactants, and thickeners.

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

8. The thick-film paste of claim 1, wherein the lead-tellurium-boron-oxide is at least partially crystalline.

9. The thick-film paste of claim 4, further comprising an additive selected from the group consisting of:

PbF₂, SiO₂, Na₂O, K₂O, Rb₂O, 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.

10. The thick film paste of claim 1, wherein the lead-tellurium-boron-oxide further comprises oxides of one or more elements selected from the group consisting of Si, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, V, Zr, Mo, Mn, Zn, B, P, Se, Sn, Ga, Ge, In, Sb, Bi, Ce, Cu, F, Ni, Cr, Fe, Co, and Ag.

23. The thick-film paste of claim 25, wherein the lead-tellurium-lithium-titanium-oxide comprises:

25-80 wt % PbO,

10-65 wt % TeO₂,

0.1-5 wt % Li₂O, and

0.1-5 wt % TiO₂.

25. The thick-film paste of claim 1, further comprising:

0.5 to 15% by weight based on solids of a lead-tellurium-lithium-titanium-oxide.

11. A process comprising:

(a) providing a semiconductor substrate comprising one or more insulating films deposited onto at least one surface of the 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-boron-oxide; and

iii) an organic medium; and

(c) firing the semiconductor substrate, insulating film, and thick-film paste, to form an electrode in contact with the insulating layer and in electrical contact with the semiconductor substrate.

12. The process of claim 11, wherein the thick-film paste composition is applied pattern-wise onto the insulating film.

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

14. The process of claim 11, wherein the thick-film paste composition further comprises:

0.5 to 15% by weight based on solids of a lead-tellurium-lithium-titanium-oxide.

15. An article comprising:

(a) a semiconductor substrate;

(b) an insulating layer on the semiconductor substrate; and

(c) an electrode in contact with the insulating layer and in electrical contact with the semiconductor substrate, the electrode comprising an electrically conductive metal and lead-tellurium-boron-oxide.

16. The article of claim 15, wherein the electrode further comprises lithium and titanium.

17. The article of claim 15, wherein the article is a semiconductor device.

18. The article of claim 17, wherein the semiconductor device is a solar cell.

19-22. -22. (canceled)

24. (canceled)