Electrical contact structure and methods for forming the same

1. An electrical contact structure disposed on a thin film material layer on a substrate, comprising:

a first barrier layer disposed on the substrate and covering a sidewall and a top surface of the thin film material layer, wherein the sidewall of the thin film material layer is at an end of the thin film material layer, and the first barrier layer has an upper portion and a lower portion, wherein the upper portion is directly above and in contact with the thin film material layer, and the lower portion is longer than the upper portion;

a metal pattern disposed on the first barrier layer, wherein the first barrier layer has a protrusion part exceeding a sidewall of the metal pattern; and

wherein the thin film material layer comprises a thin film resistance material or a thin film material of a magnetoresistance element, and the thin film resistance material comprises SiCr, NiCr or TaN, the magnetoresistance element comprises an anisotropic magnetoresistance element or a giant magnetoresistance element, and the thin film material of the magnetoresistance element comprises NiFe, CoFe, CoFeB, Cu, PtMn or IrMn.

2. The electrical contact structure of claim 1 , wherein a material of the metal pattern comprises AlCu or AlSiCu.

3. The electrical contact structure of claim 1 , wherein the first barrier layer comprises TiW, Ti or TiN.

4. The electrical contact structure of claim 1 , further comprising a protection layer disposed on the thin film material layer and the metal pattern, and the protection layer has an opening located directly on the metal pattern.

5. The electrical contact structure of claim 4 , further comprising:

a second barrier layer disposed on the metal pattern; and

an anti-reflection layer disposed on the second barrier layer, wherein the second barrier layer comprises TiW, Ti, TiN, Ta or TaN, the anti-reflection layer comprises SiON or SiN, and the opening of the protection layer exposes an upper surface of the second barrier layer.

6. The electrical contact structure of claim 5 , wherein the metal pattern, the second barrier layer and the anti-reflection layer have patterns that completely overlap one another.

7. The electrical contact structure of claim 1 , further comprising a conductive feature disposed over the lower portion of the first barrier layer.

8. The electrical contact structure of claim 1 , wherein the protrusion part has an inclined sidewall.

9. A method for forming the electrical contact structure as set forth in claim 1 , comprising:

forming a thin film material layer on a substrate, wherein the thin film material layer comprises a thin film resistance material or a thin film material of a magnetoresistance element, and the thin film resistance material comprises SiCr, NiCr or TaN, the magnetoresistance element comprises an anisotropic magnetoresistance element or a giant magnetoresistance element, and the thin film material of the magnetoresistance element comprises NiFe, CoFe, CoFeB, Cu, PtMn or IrMn;

forming a first barrier layer on the substrate and covering a sidewall and a top surface of the thin film material layer, wherein the sidewall of the thin film material layer is at an end of the thin film material layer, and the first barrier layer has an upper portion and a lower portion, wherein the upper portion is directly above and in contact with the thin film material layer, and the lower portion is longer than the upper portion;

forming a metal layer on the first barrier layer;

patterning the metal layer to form a metal pattern;

forming a spacer on a sidewall of the metal pattern and covering a portion of the first barrier layer;

etching the first barrier layer, wherein the portion of the first barrier layer located under the spacer is not completely etched; and

removing the spacer and exposing the sidewall of the metal pattern to form an electrical contact structure on the thin film material layer, wherein the first barrier layer has a protrusion part exceeding the sidewall of the metal patterns.

10. The method of claim 9 , wherein forming the spacer comprises:

forming a photoresist layer covering the metal pattern and the first barrier layer; and

performing a photoresist etch back process to form the spacer.

11. The method of claim 9 , wherein the metal layer comprises AlCu or AlSiCu.

12. The method of claim 9 , wherein the first barrier layer comprises TiW, Ti or TiN.

13. The method of claim 9 , wherein etching the first barrier layer comprises a wet-etching process, and an etchant used in the wet-etching process includes H 2 O 2 .

14. The method of claim 9 , further comprising forming a protection layer on the thin film material layer and the electrical contact structure, and the protection layer has an opening located directly on the metal pattern.

15. The method of claim 9 , further comprising:

forming a second barrier layer on the metal layer; and

forming an anti-reflection layer on the second barrier layer, wherein the second barrier layer and the anti-reflection layer are patterned at the same time in the step of patterning the metal layer to form a pattern that completely overlaps the metal pattern.

16. The method of claim 15 , wherein the second barrier layer comprises TiW, Ti, TiN, Ta or TaN, and the anti-reflection layer comprises SiON or SiN.

17. The method of claim 15 , further comprising etching the anti-reflection layer to expose an upper surface of the second barrier layer.

18. The method of claim 9 , wherein patterning the metal layer comprises a dry-etching process, and the dry-etching process stops on the first barrier layer.