Method for manufacturing magnetic tunnel junction element, and inductively coupled plasma processing apparatus
There is provided a method for manufacturing a magnetic tunnel junction element which prevents properties degradation due to hydrogen ions, and to which RIE processing that is capable of securing an etching shape is applied. A multilayer film which has a magnetic film and an oxidation film, of which a thickness of the magnetic film is 2 nm or less, and of which the magnetic film and the oxidation film have an interface in a film surface direction is generated, a mask layer that is patterned is formed on the multilayer film, etching is performed with respect to the multilayer film on which the mask layer is formed, by using a mixed gas of a hydrogen gas and a nitrogen gas as a reaction gas, and a ratio of a flow rate of the hydrogen gas to a flow rate of the mixed gas is 50% or less.
1. A method for manufacturing a magnetic tunnel junction element, comprising:
forming a multilayer film which has a first magnetic film including at least one of Co, Ni, and Fe, and an oxidation film including at least one of Mg, Zn, and Al, of which a thickness of the first magnetic film is 2 nm or less, and of which the first magnetic film and the oxidation film have an interface in a film surface direction;
forming a mask layer that is patterned on the multilayer film; and
performing etching with respect to the multilayer film on which the mask layer is formed, by using a mixed gas of a hydrogen gas and a nitrogen gas as a reaction gas,
wherein a ratio of a flow rate of the hydrogen gas to a flow rate of the mixed gas is 50% or less.
2. The method for manufacturing a magnetic tunnel junction element according to claim 1 ,
wherein the first magnetic film is formed in an upper layer than the oxidation film,
the first magnetic film is etched, by setting a ratio of the flow rate of the hydrogen gas to the flow rate of the mixed gas to be a first flow ratio,
the oxidation film is etched, by setting a ratio of the flow rate of the hydrogen gas to the flow rate of the mixed gas to be a second flow ratio, and
the second flow ratio is 50% or less, and the first flow ratio is a flow ratio of which a mask selectivity is higher than the second flow ratio.
3. The method for manufacturing a magnetic tunnel junction element according to claim 2 ,
wherein the multilayer film includes a second magnetic film that is formed in a lower layer of the oxidation film, and
the second magnetic film is etched, in accordance with the second flow ratio.
4. The method for manufacturing a magnetic tunnel junction element according to claim 1 ,
wherein etching is performed with respect to the multilayer film on which the mask layer is formed, by adding an additional gas to the mixed gas as a reaction gas, and
a rare gas including at least one of He, Ne, Ar, Kr, and Xe, or a gas including at least one of CO, CO 2 , and O is used as the additional gas.
5. The method for manufacturing a magnetic tunnel junction element according to claim 1 ,
wherein the first magnetic film is a CoFeB film, and the oxidation film is a MgO film.
6. The method for manufacturing a magnetic tunnel junction element according to claim 1 , wherein the mask layer is a Ta film.