Dry etching method for magnetic material

Abstract

A dry etching method in which a plasma of an etching gas is generated and a magnetic material is dry-etched using a mask material made of a non-organic material, wherein an alcohol having at least one hydroxyl group is used as the etching gas. The alcohol used as the etching gas has one hydroxyl group such as an alcohol selected from the group including methanol (CH 3 OH), ethanol (C 2 H 5 OH) and propanol (C 3 H 7 OH).

1. A dry etching method comprising generating a plasma of an etching gas and dry-etching a magnetic material using a mask material made of  comprising a non-organic material, wherein the etching gas is selected from the group consisting of: an alcohol having at least one hydroxyl group is used as the etching gas ; a ketone of formula RCOR′, wherein R or R′ is an alkyl group; and an alkane. 
     
     
       2. The dry etching method according to  claim 1 , wherein the alcohol used as the etching gas has one hydroxyl group. 
     
     
       3. The dry etching method according to  claim 1 , wherein the etching gas is an alcohol selected from the group consisting of methanol (CH 3 OH), ethanol (C 2 H 5 OH) and propanol (C 3 H 7 OH). 
     
     
       4. The dry etching method according to  claim 1 , wherein a mask material made of a non-organic material is a mask material comprising a single layer film or a laminated layer film made of a material selected from the group consisting of Ta, Ti, Al and Si or a mask material comprising a single layer film or a laminated layer film made of an oxide or a nitride of a material selected from the group consisting of Ta, Ti, Al and Si. 
     
     
       5. The dry etching method according to  claim 1 , wherein the magnetic material to be etched is either an elemental metal belonging to the iron group in the Group VIII or a magnetic material essentially composed of such an elemental metal. 
     
     
       6. The dry etching method according to  claim 1 , wherein an etching gas is added with at least one kind of oxygen gas, water and an inert gas as an added gas, said oxygen gas and water are added at respective content of not more than 25% relative to the etching gas and said inert gas is added at respective content of not more than 90% relative to the etching gas. 
     
     
       7. The dry etching method according to  claim 2 , wherein the etching gas is an alcohol selected from the group consisting of methanol (CH 3 OH), ethanol (C 2 H 5 OH) and propanol (C 3 H 7 OH). 
     
     
       8. The dry etching method according to  claim 2 , wherein a mask material made of a non-organic material is a mask material comprising a single layer film or a laminated layer film made of a material selected from the group consisting of Ta, Ti, Al and Si or a mask material comprising a single layer film or a laminated layer film made of an oxide or a nitride of a material selected from the group consisting of Ta, Ti, Al and Si. 
     
     
       9. The dry etching method according to  claim 3 , wherein a mask material made of a non-organic material is a mask material comprising a single layer film or a laminated layer film made of a material selected from the group consisting of Ta, Ti, Al and Si or a mask material comprising a single layer film or a laminated layer film made of an oxide or a nitride of a material selected from the group consisting of Ta, Ti, Al and Si. 
     
     
       10. The dry etching method according to  claim 2 , wherein the magnetic material to be etched is either an elemental metal belonging to the iron group in the Group VIII or a magnetic material essentially composed of such an elemental metal. 
     
     
       11. The dry etching method according to  claim 3 , wherein the magnetic material to be etched is either an elemental metal belonging to the iron group in the Group VIII or a magnetic material essentially composed of such an elemental metal. 
     
     
       12. The dry etching method according to  claim 4 , wherein the magnetic material to be etched is either an elemental metal belonging to the iron group in the Group VIII or a magnetic material essentially composed of such an elemental metal. 
     
     
       13. The dry etching method according to  claim 2 , wherein an etching gas is added with at least one kind of oxygen gas, water and an inert gas as an added gas, said oxygen gas and water are added at respective content of not more than 25% relative to the etching gas and said inert gas is added at respective content of not more than 90% relative to the etching gas. 
     
     
       14. The dry etching method according to  claim 3 , wherein an etching gas is added with at least one kind of oxygen gas, water and an inert gas as an added gas, said oxygen gas and water are added at respective content of not more than 25% relative to the etching gas and said inert gas is added at respective content of not more than 90% relative to the etching gas. 
     
     
       15. The dry etching method according to  claim 4 , wherein an etching gas is added with at least one kind of oxygen gas, water and an inert gas as an added gas, said oxygen gas and water are added at respective content of not more than 25% relative to the etching gas and said inert gas is added at respective content of not more than 90% relative to the etching gas. 
     
     
       16. The dry etching method according to  claim 5 , wherein an etching gas is added with at least one kind of oxygen gas, water and an inert gas as an added gas, said oxygen gas and water are added at respective content of not more than 25% relative to the etching gas and said inert gas is added at respective content of not more than 90% relative to the etching gas. 
     
     
       17. The dry etching method according to  claim 7 , wherein a mask material made of a non-organic material is a mask material comprising a single layer film or a laminated layer film made of a material selected from the group consisting of Ta, Ti, Al and Si or a mask material comprising a single layer film or a laminated layer film made of an oxide or a nitride of a material selected from the group consisting of Ta, Ti, Al and Si. 
     
     
       18. The dry etching method according to  claim 17 , wherein the magnetic material to be etched is either an elemental metal belonging to the iron group in the Group VIII or a magnetic material essentially composed of such an elemental metal. 
     
     
       19. The dry etching method according to  claim 18 , wherein an etching gas is added with at least one kind of oxygen gas, water and an inert gas as an added gas, said oxygen gas and water are added at respective content of not more than 25% relative to the etching gas and said inert gas is added at respective content of not more than 90% relative to the etching gas. 
     
     
       20. A tunneling magnetoresistance device ( TMR )  manufacturing method comprising:      forming a TMR comprising a pair of ferromagnetic layers comprising a free layer and a pinned layer sandwiching an insulating layer and an antiferromagnetic layer on the pinned layer on a surface thereof opposite to the insulating layer employing the dry etching process of    claim 1   .     
     
     
       21. A magnetic random access memory ( MRAM )  device manufacturing method comprising the dry etching method as defined in    claim 1   .   
     
     
       22. A magnetic random access memory ( MRAM )  device manufacturing method comprising forming a magnetic random access memory comprising a pinned layer, a free layer and an insulating layer therebetween, wherein the free layer is provided by the dry etching method of    claim 1   .   
     
     
       23. The dry etching method according to  claim 1 , wherein the magnetic material is a single or laminated layer film of at least one material selected from the group consisting of Fe—Ni alloy, Co—Fe alloy, Fe—Mn alloy, Co—Pt alloy, Ni—Fe—Cr alloy, Co—Cr alloy, Co—Pt alloy, Co—Cr—Pt alloy, Co—Pd alloy and Co—Fe—B alloy. 
     
     
       24. The dry etching method according to  claim 1 , wherein the dry etching is performed under a vacuum from  0 . 1  to  10  Pa. 
     
     
       25. The dry etching method according to  claim 1 , wherein the magnetic material is etched at a temperature from  20 -   100 ° C.