Method for removing conductive residue

1. A method of fabricating a magneto-resistive random access memory (MRAM) device from a film stack comprising a top electrode layer, a free magnetic layer, a tunnel layer, a magnetic film stack, a bottom electrode layer, and a barrier layer that are formed on a semiconductor substrate, comprising:

(a) forming a first patterned mask on the film stack to define the device;

(b) etching the top electrode layer and the free magnetic layer wherein said etching produces a first residue;

(c) stripping the first residue using a gas comprising a fluorine containing gas and a hydrogen containing gas;

(d) forming a second patterned mask on the film stack to define the device;

(e) etching the magnetic film stack and the bottom electrode wherein said etching produces a second residue; and

(f) stripping the second residue using a gas comprising a fluorine containing gas and a hydrogen containing gas.

2. The method of claim 1 wherein:

the first and the second masks comprise SiO 2 ;

the top electrode comprises at least one of Ta and TaN;

the free magnetic layer comprises at least one of NiFe or CoFe;

the tunnel layer comprises Al 2 O 3 ;

the magnetic film stack comprises at least one of NiFe, Ru, CoFe, PtMn, IrMn, NiFe, and NiFeCr;

the bottom electrode comprises at least one of Ta and TaN; and

the barrier layer comprises at least one of SiO 2 or Si 3 N 4 .

3. The method of claim 1 wherein the step (c) further comprises:

etching the tunnel layer.

4. The method of claim 1 wherein the step (c) further comprises:

stripping the first patterned mask.

5. The method of claim 1 wherein the step (f) further comprises:

etching the barrier layer.

6. The method of claim 2 wherein the step (f) further comprises:

stripping the second patterned mask.

7. The method of claim 1 wherein the steps (c) and (f) further comprise:

energizing the gas to a plasma.

8. The method of claim 7 wherein the plasma is a radio-frequency plasma having a frequency of about 200 to 600 kHz.

9. The method of claim 1 wherein the steps (c) and (f) use the fluorine containing gas comprising at least one of CF 4 and NF 3 , and use the hydrogen containing gas comprising at least one of water (H 2 O) vapor and NH 3 .

10. The method of claim 9 wherein the steps (c) and (f) further comprise:

providing CF 4 and H 2 O at a flow ratio CF 4 : H 2 O in a range from 1:10 to 10:1; applying radio-frequency power between about 1000 and 2000 W at about 200 to 600 kHz; and

maintaining a gas pressure in a range from about 1 to 5 Torr.