Method of manufacturing magnetoresistive element and method of processing magnetoresistive film
In a case where reactive ion etching using a gas containing an oxygen atom is used for etching or a magnetoresistive element, a magnetic film becomes damaged due to oxidation. Such damage to the element by the oxidation becomes a factor which causes deterioration in element properties. In the etching of the magnetoresistive element according to one embodiment of the present invention, a magnetoresistive film is subjected to ion beam etching and thereafter to reactive ion etching. A side deposition formed by the ion beam etching coats a sidewall of the magnetoresistive film and reduces damage by the oxygen atom during the later reactive ion etching. Also, a time during which the element is exposed to plasma of the gas containing the oxygen atom can be reduced.
1. A method of manufacturing a magnetoresistive element including a magnetoresistive film, comprising:
removing a portion of the magnetoresistive film having a hard mask formed thereon, in a thickness direction of the magnetoresistive film, by ion beam etching, and at the same time forming a protective film by depositing a substance removed from the magnetoresistive film by the ion beam etching on a sidewall of the magnetoresistive film having the hard mask formed thereon; and
in a state where the protective film protects the sidewall, removing the magnetoresistive film having the hard mask formed thereon by reactive ion etching by using a gas containing a carbon atom, a hydrogen atom, and an oxygen atom.
2. The method of manufacturing the magnetoresistive element according to claim 1 , wherein, in the ion beam etching, an ion beam is incident on the magnetoresistive film at an angle of 0 to 15 degrees with respect to the thickness direction of the magnetoresistive film.
3. The method of manufacturing the magnetoresistive element according to claim 1 ,
wherein the magnetoresistive film includes a magnetization free layer, a barrier layer, a magnetization pinned layer, and an antiferromagnetic layer, which are provided in sequence from a side of the hard mask,
wherein the magnetization free layer, the barrier layer, and the magnetization pinned layer are removed by the ion beam etching, and
wherein the antiferromagnetic layer is removed by the reactive ion etching.
4. The method of manufacturing the magnetoresistive element according to claim 3 , comprising:
detecting a time at which the ion beam etching reaches the antiferromagnetic layer; and
switching an etching process from the ion beam etching to the reactive ion etching, when the time at which the antiferromagnetic layer is reached is detected.
5. The method of manufacturing the magnetoresistive element according to claim 1 , wherein the gas contains at least any one of an alcohol gas and a mixed gas of hydrocarbon and oxygen.
6. The method of manufacturing the magnetoresistive element according to claim 1 , wherein one of detection of an element and emission spectrum detection of an element is performed during the ion beam etching.
7. A method of processing a magnetoresistive film, comprising:
removing a portion of the magnetoresistive film having a hard mask formed thereon, in a thickness direction of the magnetoresistive film, by ion beam etching, and at the same time forming a protective film by depositing a substance removed from the magnetoresistive film by the ion beam etching on a sidewall of the magnetoresistive film having the hard mask formed thereon; and
in a state where the protective film protects the sidewall, removing the magnetoresistive film having the hard mask formed thereon by reactive ion etching by using a gas containing a carbon atom, a hydrogen atom, and an oxygen atom.
8. The method of processing the magnetoresistive film according to claim 7 , wherein, in the ion beam etching, an ion beam is incident on the magnetoresistive film at an angle of 0 to 15 degrees with respect to the thickness direction of the magnetoresistive film.
9. The method of processing the magnetoresistive film according to claim 7 ,
wherein the magnetoresistive film includes a magnetization free layer, a barrier layer, a magnetization pinned layer, and an antiferromagnetic layer, which are provided in sequence from a side of the hard mask,
wherein the magnetization free layer, the barrier layer, and the magnetization pinned layer are removed by the ion beam etching, and
wherein the antiferromagnetic layer is removed by the reactive ion etching.
10. The method of processing the magnetoresistive film according to claim 9 , comprising:
detecting a time at which the ion beam etching reaches the antiferromagnetic layer; and
switching an etching process from the ion beam etching to the reactive ion etching, when the time at which the antiferromagnetic layer is reached is detected.
11. The method of processing the magnetoresistive film according to claim 7 , wherein the gas contains at least any one of an alcohol gas and a mixed gas of hydrocarbon and oxygen.
12. The method of processing the magnetoresistive film according to claim 7 , wherein one of detection of an element and emission spectrum detection of an element is performed during the ion beam etching.