Through silicon vias

1. A method of forming a device comprising:

providing a substrate with top and bottom surfaces;

forming a through silicon via (TSV) in the substrate through the top surface;

lining the TSV and the top surface of the substrate with an insulation stack having a first insulation layer, a polish stop layer and a second insulation layer, wherein the insulation stack lines without filling the TSV, wherein the polish stop layer lines the first insulation layer and the second insulation layer lines the polish stop layer;

forming a conductive layer on the substrate, the conductive layer filling the TSV over the insulation stack comprising the first insulation layer, the polish stop layer and the second insulation layer; and

planarizing the substrate to form a top portion of a TSV contact in the TSV, the planarizing removes excess conductive material of the conductive layer and the second insulation layer over the top surface of the substrate, the planarizing stops on the polish stop layer of the insulation stack over the top surface of the substrate, the planarizing leaves the polish stop layer remaining over the top surface of the substrate and a top surface of the conductive material in the TSV is planar with a top surface of the polish stop layer over the top surface of the substrate, forming the top portion of the TSV contact.

2. The method of claim 1 wherein lining the TSV and the top surface of the substrate with the insulation stack comprises sequentially forming the first insulation layer on the substrate, the polish stop layer over the first insulation layer and the second insulation layer over the polish stop layer.

3. The method of claim 2 wherein the first and second insulation layers comprise silicon oxide and the polish stop layer comprises silicon nitride.

4. The method of claim 1 wherein the substrate includes a device layer prior to forming the TSV.

5. The method of claim 4 wherein the device layer comprises an interlevel dielectric layer (ILD).

6. The method of claim 4 wherein the device layer comprises a top layer of the device.

7. The method of claim 6 comprises forming an interposer layer for connecting the TSV to a contact pad of the device.

8. The method of claim 1 further comprises forming a TSV barrier layer on the insulation stack prior to forming the conductive layer.

9. The method of claim 1 wherein planarizing the substrate is performed by a chemical mechanical polishing process.

10. The method of claim 1 further comprises thinning the substrate to expose a bottom of the TSV.

11. A method of forming a device comprising:

providing a substrate with top and bottom surfaces, the substrate includes a TSV formed through the top surface;

lining the TSV and the top surface of the substrate with an insulation stack having a first insulation layer, a stop layer and a second insulation layer, wherein the insulation stack lines without filling the TSV, wherein the stop layer lines the first insulation layer and the second insulation layer lines the stop layer;

forming a conductive layer on the substrate, the conductive layer filling the TSV over the insulation stack comprising the first insulation layer, the stop layer and the second insulation layer; and

removing excess conductive material of the conductive layer and the second insulation layer over the top surface of the substrate selective to the stop layer of the insulation stack over the top surface of the substrate, the removal leaves the stop layer remaining over the top surface of the substrate and a top surface of the conductive material in the TSV is planar with a top surface of the stop layer over the top surface of the substrate, forming a top portion of a TSV contact in the TSV.

12. The method of claim 11 wherein lining the TSV and the top surface of the substrate with the insulation stack comprises sequentially forming the first insulation layer on the substrate, the stop layer over the first insulation layer and the second insulation layer over the stop layer.

13. The method of claim 12 wherein the first and second insulation layers comprise silicon oxide and the stop layer comprises silicon nitride.

14. The method of claim 11 wherein the substrate comprises an interlevel dielectric layer (ILD).

15. The method of claim 14 wherein the first and second insulation layers comprise silicon oxide and the stop layer comprises silicon nitride.

16. The method of claim 11 wherein removing excess conductive material comprises chemical mechanical polishing.

17. The method of claim 11 further comprising thinning the substrate to expose a bottom of the TSV, wherein a bottom surface of the conductive material is coplanar with the bottom surface of the substrate.

18. A method of forming a device comprising:

providing a substrate with top and bottom surfaces;

forming a through silicon via (TSV) in the substrate through the top surface;

lining the TSV and the top surface of the substrate with an insulation stack having a first oxide layer, a nitride layer and a second oxide layer, wherein the insulation stack lines without filling the TSV, wherein the nitride layer lines the first oxide layer and the second oxide layer lines the nitride layer;

forming a conductive layer on the substrate, the conductive layer filling the TSV over the insulation stack comprising the first oxide layer, the nitride layer and the second oxide layer; and

planarizing the substrate to form a top portion of a TSV contact in the TSV, the planarizing removes excess conductive material of the conductive layer and the second oxide layer over the top surface of the substrate, the planarizing stops on the nitride layer of the insulation stack over the top surface of the substrate, the planarizing leaves the nitride layer remaining over the top surface of the substrate and a top surface of the conductive material in the TSV is planar with a top surface of the nitride layer over the top surface of the substrate, forming the top portion of the TSV contact.

19. The method of claim 18 wherein planarizing the substrate is performed by a chemical mechanical polishing process.

20. The method of claim 18 wherein the first and second oxide layers comprise silicon oxide and the nitride layer comprises silicon nitride.