JP2012222093A - Manufacturing method and manufacturing apparatus of magnetoresistive element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus and a manufacturing method of a magnetoresistive element capable of preventing corrosion of the element due to a halogen-based component used for etching.SOLUTION: In the manufacturing method of a magnetoresistive element 10, a first ferromagnetic layer 13 composed of a ferromagnetic material is formed on a substrate. An insulation layer 14 composed of magnesium oxide is formed on the first ferromagnetic layer 13. A second ferromagnetic layer 15 containing at least one of Fe and Co is formed on the insulation layer 14. Etching by plasma containing a halogen-based element is performed for a laminate where the first ferromagnetic layer 13, the insulation layer 14 and the second ferromagnetic layer 15 are laminated on a substrate 11. The laminate is exposed to HO plasma containing HO.

Description

  The present invention relates to a magnetoresistive element manufacturing method and manufacturing apparatus.

  A magnetoresistive element using the “magnetoresistance effect” in which the electric resistance is changed by a magnetic field is used for an MRAM (magnetoresistive random access memory), a magnetic head, a magnetic sensor, or the like. A magnetoresistive element has a structure in which a ferromagnetic layer, an insulating layer, an electrode layer, and the like are laminated. In general, a laminated body in which these materials are sequentially formed on a substrate is patterned by etching or the like. It is manufactured by doing.

Here, plasma of halogen-based elements (F, Cl, Br, I) is often used for etching the stacked body, but these halogen-based elements need to be removed after etching. This is because if a halogen-based element component remains after etching, it reacts with oxygen, moisture, etc. in the atmosphere, and the element is corroded (after-corrosion). Therefore, usually, a process for removing the halogen-based element component adhering to the element before opening to the atmosphere is performed. For example, Patent Document 1 describes a method of manufacturing a magnetic recording medium including a step of removing halogen-based active species by H ₂ plasma or the like after etching.

JP 2008-130181 A

  However, the method described in Patent Document 1 relates to a magnetic recording medium in which a magnetic layer and a nonmagnetic layer are arranged in a direction perpendicular to the stacking direction, and the magnetoresistive element in which the magnetic layer and the nonmagnetic layer are arranged in the stacking direction. It cannot be applied to.

  In view of the circumstances as described above, an object of the present invention is to provide a magnetoresistive element manufacturing apparatus and manufacturing method capable of preventing corrosion of an element due to a halogen-based component used for etching.

In order to achieve the above object, a method of manufacturing a magnetoresistive element according to an aspect of the present invention forms a first ferromagnetic layer made of a ferromagnetic material on a substrate.
An insulating layer made of magnesium oxide is formed on the first ferromagnetic layer.
The second ferromagnetic layer containing at least one of Fe and Co is formed on the insulating layer.
Etching with plasma containing a halogen-based element is performed on a stacked body in which the first ferromagnetic layer, the insulating layer, and the second ferromagnetic layer are stacked on the substrate.
The laminate is exposed in H _{2 O} plasma is a plasma containing H 2 _O.

In order to achieve the above object, a method of manufacturing a magnetoresistive element according to another aspect of the present invention includes a first ferromagnetic layer made of a ferromagnetic material, an insulating layer made of magnesium oxide, and Fe and Co on a substrate. Etching is performed with plasma containing a halogen-based element on the stacked body in which the second ferromagnetic layers containing at least one layer are stacked.
The laminate is exposed in H _{2 O} plasma is a plasma containing H 2 _O.

In order to achieve the above object, a magnetoresistive element manufacturing apparatus according to an embodiment of the present invention includes an etching chamber and a plasma processing chamber.
The etching chamber includes an etching chamber that irradiates a processing target with plasma containing a halogen-based element;
The plasma processing chamber irradiates the processing object with H ₂ O plasma, which is a plasma containing H ₂ O.

It is a schematic diagram which shows schematic structure of the magnetoresistive element which concerns on 1st Embodiment. It is a schematic diagram which shows the example of the constituent material of each layer of the said magnetoresistive element. It is a schematic diagram which shows schematic structure of the laminated body used as the said magnetoresistive element. It is a schematic diagram which shows schematic structure of the patterning apparatus of the said laminated body. It is a schematic diagram which shows schematic structure of the 1st etching chamber of the said patterning apparatus, and a 2nd etching chamber. It is a schematic diagram which shows schematic structure of the plasma processing chamber of the said patterning apparatus. It is a flowchart which shows the patterning method of the said laminated body. It is a schematic diagram which shows the state after the resist mask formation process of the said laminated body. It is a schematic diagram which shows the state after the 1st etching process of the said laminated body. It is a schematic diagram which shows the state after the ashing process of the said laminated body. It is a schematic diagram which shows the state after the 2nd etching process of the said laminated body. It is a schematic diagram which shows schematic structure of the magnetoresistive element which concerns on 2nd Embodiment. It is a schematic diagram which shows the example of the constituent material of each layer of the said magnetoresistive element. It is a schematic diagram which shows schematic structure of the laminated body used as the said magnetoresistive element. It is a schematic diagram which shows the state after the resist mask formation process of the said laminated body. It is a schematic diagram which shows the state after the 1st etching process of the said laminated body. It is a schematic diagram which shows the state after the ashing process of the said laminated body. It is a schematic diagram which shows the state after the 2nd etching process of the said laminated body.

In the method of manufacturing a magnetoresistive element according to an embodiment of the present invention, a first ferromagnetic layer made of a ferromagnetic material is formed on a substrate.
An insulating layer made of magnesium oxide is formed on the first ferromagnetic layer.
The second ferromagnetic layer containing at least one of Fe and Co is formed on the insulating layer.
Etching with plasma containing a halogen-based element is performed on a stacked body in which the first ferromagnetic layer, the insulating layer, and the second ferromagnetic layer are stacked on the substrate.
The laminate is exposed in H _{2 O} plasma is a plasma containing H 2 _O.

In the stacked body etched with plasma containing halogen elements (F, Cl, Br, I), the halogen elements remain even after the etching is completed. When the laminated body in this state is exposed to the atmosphere, the residual components of the halogen element react with the atmosphere to generate halogenated Co (CoCl ₂ , CoCl _3, etc.), halogenated Fe (FeCl ₂ , FeCl _2, etc.), Each layer of the laminate corrodes (after-corrosion). In this embodiment, by exposing the stacked body to H ₂ O plasma after etching, it is possible to remove the residual components of the halogen-based element and prevent the corrosion.

In the step of exposing the laminate to H ₂ O plasma, the laminate may be heated to 200 ° C. or higher.

By heating the stacked body simultaneously with the H ₂ O plasma, the generation of hydrogen halide (HCl, HBr, etc.) due to the residual components of the halogen-based element is promoted. Since hydrogen halide has volatility, it is possible to speed up the removal of residual components by heating the laminate.

The _{H 2} O plasma, _{H 2} addition to _{O H 2, He, O 2} , N 2, Ar, may be any plasma that includes one or more Ne and Xe.

Promotes the formation of hydrogen halide by the addition of H ₂ in H 2 _O, it is possible to speed up the removal of residual components, the life of H _{2 O} radicals by adding N ₂ in H 2 _O It can be extended. Further, in the case where the resist ashing and the removal of the residual components of the halogen element are performed simultaneously, the ashing speed and the residual component removal speed are controlled by adding an inert gas (Ar, Ne, Xe) to H ₂ O. It becomes possible. In this case, the ashing speed can be increased by adding O ₂ , which is an ashing gas, to H ₂ O.

A method for manufacturing a magnetoresistive element according to an embodiment of the present invention includes a first ferromagnetic layer made of a ferromagnetic material, an insulating layer made of magnesium oxide, and at least one of Fe and Co on a substrate. Etching is performed on the laminated body in which the ferromagnetic layers are laminated with plasma containing a halogen element.
The laminate is exposed in H _{2 O} plasma is a plasma containing H 2 _O.

A magnetoresistive element manufacturing apparatus according to an embodiment of the present invention includes an etching chamber and a plasma processing chamber.
The etching chamber includes an etching chamber that irradiates a processing target with plasma containing a halogen-based element;
The plasma processing chamber irradiates the processing object with H ₂ O plasma, which is a plasma containing H ₂ O.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
The magnetoresistive element according to the first embodiment of the present invention will be described.

[Configuration of magnetoresistive element]
FIG. 1 is a cross-sectional view showing a schematic configuration of a magnetoresistive element according to an embodiment of the present invention. As shown in the figure, the magnetoresistive element 10 has a configuration in which a lower electrode layer 12, a pinned layer (magnetization pinned layer) 13, an insulating layer 14, a free layer 15, and an upper electrode layer 16 are laminated on a substrate 11 in this order. Have. Note that the thickness of each layer shown in FIG. 1 is not proportional to the actual thickness. The magnetoresistive element 10 constitutes a tunnel magnetoresistive effect element (TMR (tunnel magneto-resistance) element) having the insulating layer 14 as a tunnel junction layer (barrier layer). For example, an STT-MRAM, a magnetic head, a magnetic sensor, etc. It is used as various magnetic devices.

  The substrate 11 is composed of a semiconductor substrate such as a silicon substrate, but is not limited thereto, and may be a ceramic substrate or a glass substrate. The lower electrode layer 12 is a conductor layer made of metal or the like configured as a lower electrode of the magnetoresistive element 10. The pinned layer 13 is composed of a ferromagnetic material layer whose magnetization direction is fixed. The insulating layer 14 joins between the pinned layer 13 and the free layer 15 and is composed of magnesium oxide (MgO). The free layer 15 is composed of a ferromagnetic material layer whose magnetization direction can be changed. The upper electrode layer 16 is a conductor layer made of metal or the like configured as the upper electrode of the magnetoresistive element 10.

  Of each layer of the magnetoresistive element 10, the pinned layer 13, the insulating layer 14, the free layer 15 and the upper electrode layer 16 are patterned, and the lower electrode layer 12 is partially exposed. Such patterning is for insulation from an adjacent magnetoresistive element (not shown), and the patterning pattern is not limited to that shown.

  The magnetoresistive element 10 can record or read information by utilizing a change in resistance value due to a difference between the magnetization direction of the pinned layer 13 and the magnetization direction of the free layer 15. For example, the resistance value is the smallest when the magnetization directions of the layers are the same (parallel), and the resistance value is the largest when the magnetization directions of the layers are opposite (antiparallel). Therefore, by defining each data as “0” for the former magnetization mode and “1” for the latter magnetization mode, digital information can be recorded or read by the element. In the case of an STT-MRAM, recording (writing) and reading of information are performed by supplying current to the free layer 15 through the lower electrode layer 12 and the upper electrode layer 16.

  Each layer of the magnetoresistive element 10 is composed of a single layer or a stack of various materials. FIG. 2 is a diagram illustrating an example of a constituent material of each layer of the magnetoresistive element 10.

  The lower electrode layer 12 may have a structure in which a Ta (tantalum) layer 21, a Ru (ruthenium) layer 22, and a Ta layer 23 are laminated in this order. In addition, the lower electrode layer 12 can be made of various electrode materials.

The pinned layer 13 may have a structure in which a PtMn (platinum manganese) layer 24, a CoFeB (cobalt iron boron) layer 25, a Ru layer 26, and a CoFeB layer 27 are laminated in this order. The pinned layer 13 is made of one or more kinds of metals such as Fe (iron), Co (cobalt), Ni (nickel), Ir (iridium), Pt (platinum), Mn (manganese), etc. In addition, on a layer made of an alloy such as CoFe or CoFeB, a perpendicular magnetization artificial lattice such as CoB / Pt, an L10 ordered alloy (FePt, CoPt), an L11 ordered alloy (CoPt), a phase separation alloy (CoCrPt, CoCrPt—SiO ₂₎ ), Heusler alloy (CoMnSi), amorphous rare earth (TbFeCo), and the like. Further, these materials may contain metalloid elements such as Si (silicon), B (boron), and P (phosphorus).

  The insulating layer 14 can be composed of a single MgO (manganese oxide) layer 28.

The free layer 15 can be composed of a single layer of CoFe (cobalt iron) layer 29. In addition, the free layer 15 may be made of a material containing at least one of Fe and Co. The free layer 15 is formed on a layer made of an alloy such as CoFe or CoFeB, a perpendicular magnetization artificial lattice such as CoB / Pt, an L10 ordered alloy (FePt, CoPt), an L11 ordered alloy (CoPt), or a phase separation alloy ( A material such as CoCrPt, CoCrPt—SiO ₂ ), Heusler alloy (CoMnSi), amorphous rare earth (TbFeCo) or the like may be further laminated.

  The upper electrode layer 16 can be composed of a single Ta layer 30. In addition, the upper electrode layer 16 can be made of various electrode materials.

  The magnetoresistive element 10 is configured as described above.

[Configuration of laminate]
The magnetoresistive element 10 can be produced by patterning a “laminate” in which the above layers are formed on a substrate 11. FIG. 3 is a schematic diagram showing a laminated body 40 to be the magnetoresistive element 10.

  As shown in the figure, the laminate 40 is formed on the Ta layer 41, Ru layer 42, Ta layer 43, PtMn layer 44, CoFeB layer 45, Ru layer 46, CoFeB layer 47, MgO layer 48, CoFe on the substrate 11. The layer 49 and the Ta layer 50 are laminated in this order. Each layer of the laminated body 40 corresponds to each layer of the magnetoresistive element 10, and the material can be changed according to the material of each layer.

[Production method of laminate]
The stacked body 40 includes a Ta layer 41, a Ru layer 42, a Ta layer 43, a PtMn layer 44, a CoFeB layer 45, a Ru layer 46, a CoFeB layer 47, an MgO layer 48, a CoFe layer 49, and a Ta layer 50 on the substrate 11. It can manufacture by forming into a film in order. Each layer can be formed by various film forming methods such as sputtering and vacuum deposition. For example, the thickness of each layer may be 2 nm for the MgO layer 48, 5 nm for the CoFe layer 49, and 10 nm for the Ta layer 50. The laminate 40 is produced in this way. In addition, the manufacturing method of the laminated body 40 is not restricted to what is shown here.

  The laminated body 40 manufactured in this way has the PtMn layer 44, the CoFeB layer 45, the Ru layer 46, the CoFeB layer 47, the MgO layer 48, the CoFe layer 49, and the Ta layer 50 patterned to form the magnetoresistive element 10 and Become.

[Layering patterning device]
A patterning apparatus used for patterning the stacked body 40 will be described. FIG. 4 is a schematic diagram illustrating a schematic configuration of the patterning device 100 for the stacked body 40. As shown in the figure, the patterning apparatus 100 is a multi-chamber apparatus, and includes an L / UL (load / unload) chamber 101, a transfer chamber 102, a preheat chamber 103, a first etching chamber 104, a second etching chamber 105, An ashing chamber 106 and a plasma processing chamber 107 are provided.

  In the patterning apparatus 100, an L / UL (load / unload) chamber 101, a preheat chamber 103, a first etching chamber 104, a second etching chamber 105, an ashing chamber 106, and a plasma processing chamber 107 are connected to a transfer chamber 102, respectively. It has a configuration. The configuration of the patterning apparatus 100 is not limited to that shown here.

  The L / UL chamber 101 has a double opening / closing door, and is a chamber for carrying the laminate 40 into and out of the patterning apparatus 100. The transfer chamber 102 is a chamber in which a transfer robot (not shown) is installed, and the stacked body 40 loaded from the L / UL chamber 101 is moved to each chamber.

  The preheat chamber 103 is a chamber for heating the laminated body 40, and a heater (not shown) is provided in the chamber. The first etching chamber 104 and the second etching chamber 105 are chambers for etching the stacked body 40. FIG. 5 is a schematic diagram showing the configuration of the second etching chamber 105 having the same configuration as the first etching chamber 104 and the first etching chamber 104.

  As shown in the figure, a chamber 201 is provided in the first etching chamber 104 (the same applies to the second etching chamber 105). An evacuation system 202 for evacuating the chamber 201 is connected to the chamber 201. The vacuum exhaust system 202 includes a vacuum pump such as a turbo molecular pump and its piping. A stage 203 that supports the stacked body 40 is installed inside the chamber 201. An electrostatic chuck that holds the stacked body 40 placed thereon is provided on the upper surface of the stage 203, and He (helium) gas is introduced between the stage 203 and the stacked body 40 after the chuck. Using this He gas as a heat medium, the temperature of the stage 203 can be conducted to the laminated body 40, and at the same time, the temperature of the entire laminated body 40 is equalized.

  The etching chamber 104 is provided with a chiller circulation unit 204 that circulates the heat medium while controlling the temperature inside the stage 203. The chiller circulation unit 204 can maintain the stage 203 at a predetermined temperature. A commercially available heat medium (liquid) can be used as the heat medium, and the heat medium is supplied to the stage 203 by the chiller circulation unit 204.

  As another method, the stage 203 can be heated not by the heat medium from the chiller circulation unit 204 but by a heating mechanism using a heater wire built in the stage 203. In the case of heating with a chiller, the maximum heating temperature is about 200 ° C., whereas in the case of using a heater wire, it is possible to heat to 450 ° C. However, in order to prevent problems such as melting of O-rings and the like at various places, it is necessary to cool the side in contact with the wall of the chamber 203 through a heat insulating plate by a chiller in contrast to the conventional case.

A deposition plate 205 that divides the plasma formation space is provided around the stage 203, and a gas introduction system 206 for introducing an etching gas (a gas that is a source of plasma for etching) into the plasma formation space. Is connected. The gas introduction system 206 is composed of a gas source such as a gas cylinder, its piping, and a mass flow controller provided on the piping. The etching gas may be a Cl ₂ / BCl ₃ mixed gas in the first etching chamber 104 and an Ar / O ₂ / Cl ₂ mixed gas in the second etching chamber 105. Further, in the first etching chamber 104 and the second etching chamber 105, other halogen-based gases (Cl ₂ , HBr, HI, CF _4, etc.) may be used as the etching gas.

  Further, the etching chamber 104 is provided with an antenna 207, a high-frequency power source 208, and a magnet unit 209 as a plasma generation mechanism. The antenna 207 is arranged on the upper part of the lid 210 that closes the upper part of the plasma forming space, and is connected to the high frequency power source 208 to form a high frequency induction electric field in the plasma forming space. The magnet unit 209 is installed on the top of the lid 210 and forms a fixed magnetic field in the plasma formation space. The etching gas introduced into the plasma formation space via the gas introduction system 206 is turned into plasma by receiving the action of the induction electric field by the antenna 207 and the action of the fixed magnetic field by the magnet unit 209. Further, the etching chamber 104 may be provided with a bias power supply 211 that attracts ions in the plasma toward the stage 203 side. The bias power supply 211 can be composed of a high frequency power supply.

  The ashing chamber 106 is a chamber for removing a resist mask (described later) applied to the stacked body 40. The ashing chamber 106 accommodates a plasma generation mechanism (not shown) for plasma ashing. There are various plasma generation mechanisms such as an ICP (Inductively coupled plasma) type and a microwave type, and any type can be used.

  The plasma processing chamber 107 is a chamber for performing plasma processing on the stacked body 40. FIG. 6 is a schematic diagram showing a schematic configuration of the plasma processing chamber 107. As shown in the figure, the plasma processing chamber 107 includes a chamber 301, a heater 302, a vacuum exhaust system 303, a gas introduction system 304, a plasma source 305 and a plasma introduction pipe 306. In the heater 302, the stacked body 40 placed on the heater 302 is shown.

  The heater 302 is accommodated in the chamber 301, and an evacuation system 303 is connected to the chamber 301. A plasma introduction pipe 306 is connected to the surface of the chamber 301 facing the laminate 40, and the plasma source 305 is connected to the chamber 301 via the plasma introduction pipe 306. A gas introduction system 304 is connected to the plasma introduction pipe 306 in the vicinity of the plasma source 305.

  The heater 302 is for heating the laminated body 40 and promoting vaporization (described later) of the halogen-based element. The heater 302 may be capable of heating the laminate 40 to, for example, 200 ° C. or higher. The vacuum exhaust system 303 includes a vacuum pump such as a dry pump and its piping.

The gas introduction system 304 includes a gas source such as a gas cylinder and its piping, and a mass flow controller provided on the piping. In the present embodiment, H ₂ O gas may be supplied to the plasma introduction pipe 306 as a gas that is a source of plasma. Incidentally, H 2 _O is supplied in a liquid state, it can be assumed to be a water vapor by the carburetor. Further, as a source gas of plasma, a gas obtained by mixing one or more of H ₂ O with H ₂ , He, O ₂ , N ₂ , Ar, Ne, and Xe may be used.

Promotes the formation of hydrogen halide by the addition of H ₂ in H 2 _O, it is possible to speed up the removal of residual components, the life of H _{2 O} radicals by adding N ₂ in H 2 _O It can be extended. Further, in the case where the ashing of the resist and the removal of the residual components of the halogen-based element are simultaneously performed (described later), the ashing speed and the residual component removal speed are obtained by adding an inert gas (Ar, Ne, Xe) to H ₂ O. Can be controlled. In this case, the ashing speed can be increased by adding O ₂ , which is an ashing gas, to H ₂ O.

  The plasma source 305 can be a microwave plasma source, a high frequency plasma source, or a low frequency plasma source. The plasma generation method may be ICP (Inductively coupled plasma) or CCP (Capacitively Coupled Plasma), and the electrode shape may be a coil shape or a parallel plate shape. In the case of high-frequency discharge, a structure in which a mesh having a ground potential is inserted between the plasma source 305 and the stacked body 40 to irradiate the stacked body 40 only with radicals may be employed.

In the plasma processing chamber 107, the stacked body 40 is heated by the heater 302 while the chamber 301 is evacuated by the evacuation system 303. When the laminated body 40 reaches a predetermined temperature, microwave plasma or the like is radiated from the plasma source 305 and irradiated to the gas introduced from the gas introduction system 304. The generated plasma flows into the chamber 301 through the plasma introduction pipe 306 and is irradiated on the stacked body 40. Note that the plasma treatment chamber 107 is not limited to the structure shown here and can have a structure in which the stacked body 40 can be irradiated with plasma such as H ₂ O while the stacked body 40 is heated.

  The patterning apparatus 100 is configured as described above. In the patterning apparatus 100, the ashing chamber 106 and the plasma processing chamber 107 are separate chambers, but these chambers may be a single chamber.

[Layering patterning method]
A method for patterning the stacked body 40 using the patterning apparatus 100 will be described. FIG. 7 is a flowchart showing a method for patterning the stacked body 40. As shown in the figure, the laminate 40 is patterned through the following steps. That is, resist mask formation (St1), first etching (St2), ashing (St3), second etching (St4), and plasma treatment (St5). 8 to 11 are schematic views showing the state of the stacked body 40 in each step.

“Resist mask formation (St1)”
As shown in FIG. 8, a resist mask R is formed on the surface of the stacked body 40, that is, on the Ta layer 50. The resist mask R can be formed using a general photolithography technique. The pattern (shape) of the resist mask R is appropriately determined according to the pattern of the magnetoresistive element 10 to be manufactured.

  The stacked body 40 on which the resist mask R is formed is carried into the patterning apparatus 100 via the L / UL chamber 101. The stacked body 40 is carried into the first etching chamber 104 by the transfer robot in the transfer chamber 102.

"First etching (St2)"
The stacked body 40 is etched in the first etching chamber 104 using the resist mask R as an etching mask. Specifically, a Cl ₂ / BCl ₃ mixed gas is introduced into the plasma formation space from the gas introduction system 206 (see FIG. 5), and the plasma is received by the action of the induction electric field by the antenna 207 and the action of the fixed magnetic field by the magnet unit 209. It becomes. The respective flow rates of Cl ₂ gas and BCl ₃ gas can be Cl ₂ : 10 to 40 sccm and BCl ₃ : 10 to 40 sccm. The temperature of the stacked body 40 can be room temperature, the pressure in the chamber 201 can be 0.3 to 3 Pa, the antenna power can be 500 to 1500 W, the bias power can be 50 to 150 W, and the etching time can be 15 seconds or less.

Under such conditions, the laminate 40 is irradiated with Cl ₂ / BCl ₃ plasma, and a region of the Ta layer 50 that is not covered with the resist mask R is etched. FIG. 9 is a schematic diagram showing the stacked body 40 etched by the first etching process. The CoFe layer 49 is not etched in this etching process due to the difference in etching property with the Ta layer 50. Thereafter, the stacked body 40 is carried into the ashing chamber 106 by the transfer robot.

"Ashing (St3)"
The laminated body 40 is subjected to ashing in the ashing chamber 106, and the resist mask R is removed. FIG. 10 is a schematic diagram showing the stacked body 40 from which the resist mask R has been removed. Ashing can be plasma ashing in which the resist mask R is exposed to plasma such as H ₂ , O _2, or H ₂ O. The ashing conditions in the case of using O ₂ plasma can be an O ₂ pressure of 10 to 300 Pa, an applied power of 1000 to 3000 W, a bias power of 0 to 100 W (RF), a heating temperature of 20 to 300 ° C., and an ashing time of 30 seconds. . Thereafter, the stacked body 40 is carried into the preheat chamber 103 by the transfer robot. Note that this ashing step is not performed at this point, and can be performed simultaneously with a plasma processing step (St5) described later.

"Second etching (St4)"
The laminated body 40 is heated to a predetermined temperature by the preheating chamber 103. The predetermined temperature can be 150 to 300 ° C. Thereafter, the stacked body 40 is carried into the second etching chamber 105 by the transfer robot. Note that the stacked body 40 may be carried into the second etching chamber 105 immediately after the ashing step (St3) and heated to a predetermined temperature in the second etching chamber 105.

After the stack 40 is heated, it is etched in the second etching chamber 105 using the Ta layer 50 as an etching mask. Specifically, an Ar / O ₂ / Cl ₂ mixed gas is introduced into the plasma formation space from the gas introduction system 206 (see FIG. 5), and the effect of the induction electric field by the antenna 207 and the effect of the fixed magnetic field by the magnet unit 209 are received. It is turned into plasma. The flow rates of Ar gas, O ₂ gas, and Cl ₂ gas may be Ar: 5 to 40 sccm, O ₂ : 10 to 30 sccm, and Cl ₂ : 5 to 50 sccm. The temperature of the laminate 40 is 150 to 300 ° C., the pressure in the chamber 201 is 0.3 to 3 Pa, the antenna power is 500 to 1500 W, the bias power is 300 to 800 W, and the etching time is 30 to 200 seconds. it can.

Under such conditions, the laminate 40 is irradiated with Ar / O ₂ / Cl ₂ plasma. Here, since the Ar / O ₂ / Cl ₂ plasma has no (or small) etching property with respect to Ta, it is sandwiched between the CoFe layer 49 to the PtMn layer 44 (the CoFe layer 49 and the PtMn layer 44 and these two layers). Of each layer, the same applies hereinafter), the region where the Ta layer 50 does not exist in the upper layer is etched. FIG. 11 is a schematic diagram showing the stacked body 40 etched in the second etching step.

Here, the residual component of Ar / O ₂ / Cl ₂ plasma (hereinafter referred to as an etching residual component) exposed to the stacked body 40 in this etching step is attached to the stacked body 40. However, since the stacked body 40 is accommodated in a vacuum environment (or a process gas atmosphere), the stacked body 40 is not corroded by the etching residual components. If the laminated body 40 is taken out into the atmosphere at this time, an etching residual component, particularly a Cl component, reacts with Co or Fe to produce CoCl ₂ , CoCl ₃ , FeCl ₂ , FeCl _3, etc. Each layer is corroded. This is not limited to Cl, and the same applies when a halogen-based gas plasma is used in this step. After this step, the stacked body 40 is carried into the plasma processing chamber 107.

"Plasma treatment (St5)"
The laminated body 40 is subjected to plasma processing in the plasma processing chamber 107, and the etching residual component is removed. Specifically, H ₂ O gas is introduced into the plasma introduction pipe 306 from the gas introduction system 304 (see FIG. 6), and the gas is converted into plasma by microwaves or the like emitted from the plasma source 305. The flow rate of H ₂ O gas can be 500 sccm, the pressure can be 300 Pa, the microwave discharge power can be 2000 W, and the plasma treatment time can be 60 seconds. The generated plasma is irradiated to the laminate 40 through the plasma introduction pipe 306. At the same time, the laminate 40 is heated to a predetermined temperature by the heater 302. The heating temperature of the laminated body 40 can be 200 degreeC.

  Thereby, the etching residual component adhering to the laminated body 40 causes a chemical reaction. For example, HCl is generated when the Cl component remains as described above. Similarly, when the Br (bromine) component remains, HBr, I (iodine) component generate HI, F (fluorine) component generate HF, and the like. These hydrogen halides have volatility, and since the plasma processing chamber 107 is depressurized, the stacked body 40 is further heated by the heater 302, so that it quickly volatilizes.

  The laminated body 40 is patterned as described above, and the magnetoresistive element 10 shown in FIG. Since the etching residual component is removed by the plasma treatment process as described above, it is possible to prevent the occurrence of corrosion (after-corrosion) due to the etching residual component of the magnetoresistive element 10.

(Second Embodiment)
A magnetoresistive element according to the second embodiment of the present invention will be described.
In the second embodiment, the element structure of the magnetoresistive element is different from that of the first embodiment, and the etching type, the order of etching, and the like are different.

[Configuration of magnetoresistive element]
FIG. 12 is a cross-sectional view showing a schematic configuration of a magnetoresistive element according to an embodiment of the present invention. As shown in the figure, the magnetoresistive element 410 has a configuration in which a lower electrode layer 412, a pinned layer (magnetization pinned layer) 413, an insulating layer 414, a free layer 415, and an upper electrode layer 416 are sequentially stacked on a substrate 411. Have. Note that the thickness of each layer shown in FIG. 12 is not proportional to the actual thickness.

Since the function of each layer is the same as that of the magnetoresistive element 10 according to the first embodiment, the description thereof is omitted.
Of the layers of the magnetoresistive element 410, the free layer 415 and the upper electrode layer 416 are patterned, and the insulating layer 414 partially exposes. Such patterning is for insulation from an adjacent magnetoresistive element (not shown), and the patterning pattern is not limited to that shown.

  Each layer of the magnetoresistive element 410 is composed of a single layer or a stack of various materials. FIG. 13 is a diagram illustrating an example of a constituent material of each layer of the magnetoresistive element 410.

  The lower electrode layer 412 can have a structure in which a Ta layer 421, a Ru layer 422, and a Ta layer 423 are stacked in this order. In addition, the lower electrode layer 412 can be made of various electrode materials.

The pinned layer 413 can have a structure in which a PtMn layer 424, a CoFeB layer 425, a Ru layer 426, and a CoFeB layer 427 are stacked in this order. In addition to this, the pinned layer 413 is made of one or plural kinds of metals such as Fe, Co, Ni, Ir, Pt, Mn, etc., or on a layer made of an alloy such as CoFe or CoFeB. Materials such as perpendicular magnetization artificial lattice, L10 ordered alloy (FePt, CoPt), L11 ordered alloy (CoPt), phase separation system alloy (CoCrPt, CoCrPt—SiO ₂ ), Heusler alloy (CoMnSi), amorphous rare earth (TbFeCo) It can be laminated. Further, these materials may contain metalloid elements such as Si, B, and P.

  The insulating layer 414 can be composed of a single layer of MgO layer 428.

The free layer 415 can be composed of a single CoFe layer 429. In addition, the free layer 415 can be made of a material containing at least one of Fe and Co. The free layer 415 is formed on a layer made of an alloy such as CoFe or CoFeB, a perpendicular magnetization artificial lattice such as CoB / Pt, an L10 ordered alloy (FePt, CoPt, etc.), an L11 ordered alloy (CoPt, etc.), or a phase separation system. A material such as an alloy (CoCrPt, CoCrPt—SiO ₂ or the like), Heusler alloy (CoMnSi or the like), amorphous rare earth (TbFeCo or the like), or the like can be further laminated.

  The upper electrode layer 416 can be composed of a single Ru layer 430. In addition to this, the upper electrode layer 416 can be made of various electrode materials such as Ta and Cr, and their laminated films, alloy films, or conductive oxide films.

  The magnetoresistive element 410 is configured as described above.

[Configuration of laminate]
The magnetoresistive element 410 can be formed by patterning a “stacked body” in which the above layers are formed on a substrate 411. FIG. 14 is a schematic view showing a laminated body 440 that becomes the magnetoresistive element 410.

  As shown in the figure, the stacked body 440 includes a Ta layer 441, a Ru layer 442, a Ta layer 443, a PtMn layer 444, a CoFeB layer 445, a Ru layer 446, a CoFeB layer 447, an MgO layer 448, and a CoFe layer. A layer 449 and a Ru layer 450 are stacked in this order. Each layer of the laminated body 440 corresponds to each layer of the magnetoresistive element 410, and the material can be changed according to the material of each layer.

[Production method of laminate]
The stacked body 440 includes a Ta layer 441, a Ru layer 442, a Ta layer 443, a PtMn layer 444, a CoFeB layer 445, a Ru layer 446, a CoFeB layer 447, a MgO layer 448, a CoFe layer 449, and a Ta layer 450 over a substrate 411. It can manufacture by forming into a film in order. Each layer can be formed by various film forming methods such as sputtering and vacuum deposition. For example, the thickness of each layer can be 2 nm for the MgO layer 448, 5 nm for the CoFe layer 449, and 10 nm for the Ta layer 450. The laminated body 440 is produced in this way. Note that the method for manufacturing the stacked body 440 is not limited to the one shown here.

  The stacked body 440 thus manufactured becomes the magnetoresistive element 410 by patterning the CoFe layer 449 and the Ru layer 450.

[Layering patterning device]
A patterning apparatus used for patterning the stacked body 440 will be described. For patterning the stacked body 440, a patterning apparatus having the same configuration as that of the patterning apparatus 100 (see FIG. 4) of the first embodiment can be used. Only the configuration different from that of the patterning apparatus 100 will be described below.

Gas introduced from the gas introduction system 206 of the first etching chamber 104 and the second etching chamber 105 may be a Cl ₂ gas for _Cl 2 / _{O 2} gas, a second etching chamber 105 for the first etching chamber 104 . Further, in the first etching chamber 104 and the second etching chamber 105, other halogen-based gases (Cl ₂ , HBr, HI, CF _4, etc.) may be used as the etching gas.

  The patterning apparatus 100 according to the second embodiment is configured as described above.

[Layering patterning method]
A method for patterning the stacked body 440 using the patterning apparatus 100 will be described. Note that the flowchart showing the patterning method of the stacked body 440 is the same as the flowchart (FIG. 7) of the panning method according to the first embodiment, so that the illustration is omitted.

  As shown in FIG. 7, the laminated body 440 is patterned through the following steps. That is, resist mask formation (St1), first etching (St2), ashing (St3), second etching (St4), and plasma treatment (St5). 15 to 18 are schematic views showing the state of the stacked body 440 in each step.

“Resist mask formation (St1)”
As shown in FIG. 15, a resist mask R is formed on the surface of the stacked body 440, that is, on the Ru layer 450. The resist mask R can be formed using a general photolithography technique. The pattern (shape) of the resist mask R is appropriately determined according to the pattern of the magnetoresistive element 410 to be manufactured.

  The stacked body 440 on which the resist mask R is formed is carried into the patterning apparatus 100 via the L / UL chamber 101. The stacked body 440 is carried into the first etching chamber 104 by the transfer robot in the transfer chamber 102.

"First etching (St2)"
The stacked body 440 is etched in the first etching chamber 104 using the resist mask R as an etching mask. Specifically, a Cl ₂ / O ₂ mixed gas is introduced into the plasma formation space from the gas introduction system 206 (see FIG. 5), and the plasma is received by the action of the induction electric field by the antenna 207 and the action of the fixed magnetic field by the magnet unit 209. It becomes. The flow rates of the Cl ₂ gas and the O ₂ gas can be Cl ₂ : 10 to 40 sccm and O ₂ : 5 to ₂₀ sccm. The temperature of the stacked body 440 can be room temperature, the pressure in the chamber 201 can be 0.3 to 3 Pa, the antenna power is 500 to 1500 W, the bias power is 50 to 150 W, and the etching time is 30 seconds or less.

Under such conditions, the laminate 440 is irradiated with Cl ₂ / O ₂ plasma, and a region of the Ru layer 450 that is not covered with the resist mask R is etched. FIG. 16 is a schematic diagram showing the stacked body 440 etched by the first etching process. Note that the CoFe layer 449 is not etched in this etching process due to the difference in etching property with the Ta layer 450. Thereafter, the stacked body 440 is carried into the ashing chamber 106 by the transfer robot.

"Ashing (St3)"
The stacked body 440 is subjected to ashing in the ashing chamber 106, and the resist mask R is removed. FIG. 17 is a schematic diagram showing the stacked body 440 from which the resist mask R has been removed. Ashing can be plasma ashing in which the resist mask R is exposed to plasma such as H ₂ , O _2, or H ₂ O. The ashing conditions in the case of using O ₂ plasma can be an O ₂ pressure of 10 to 300 Pa, an applied power of 1000 to 3000 W, a bias power of 0 to 100 W (RF), a heating temperature of 20 to 300 ° C., and an ashing time of 30 seconds. . Thereafter, the stacked body 440 is carried into the preheat chamber 103 by the transfer robot. Note that this ashing step is not performed at this point, and can be performed simultaneously with a plasma processing step (St5) described later.

"Second etching (St4)"
The laminated body 440 is heated to a predetermined temperature by the preheating chamber 103. Heating can be performed at a temperature of the stacked body 440 of 150 to 350 ° C. Thereafter, the stacked body 440 is carried into the second etching chamber 105 by the transfer robot. Note that the stacked body 440 may be carried into the second etching chamber 105 immediately after the ashing step (St3) and heated to a predetermined temperature in the second etching chamber 105.

After the heating, the stacked body 440 is etched in the second etching chamber 105 using the Ru layer 450 as an etching mask. Specifically, Cl ₂ gas is introduced into the plasma formation space from the gas introduction system 206 (see FIG. 5), and is converted into plasma under the action of the induction electric field by the antenna 207 and the action of the fixed magnetic field by the magnet unit 209. The flow rate of the Cl ₂ gas can be 20 to 100 sccm. The temperature of the stacked body 440 can be 150 to 350 ° C., the pressure in the chamber 201 can be 0.5 to 3 Pa, the antenna power is 500 to 3000 W, the bias power is 0 to 50 W, and the etching time is 60 seconds or less.

Under such conditions, the laminate 440 is irradiated with Cl ₂ plasma. Here, since the Cl ₂ plasma does not have (or is small) an etching property with respect to Ru and MgO, a region where the Ru layer 450 does not exist on the CoFe layer 449 is etched. FIG. 18 is a schematic diagram showing the stacked body 440 etched in the second etching step.

Here, a residual component of Cl ₂ plasma exposed to the stacked body 440 in the present etching step (hereinafter referred to as an etching residual component) is attached to the stacked body 440. However, since the stacked body 440 is accommodated in a vacuum environment (or a process gas atmosphere), the stacked body 440 is not corroded by etching residual components. If the laminated body 440 is taken out into the atmosphere at this time, the etching residual component, particularly the Cl component reacts with Co or Fe to produce CoCl ₂ , CoCl ₃ , FeCl ₂ , FeCl _3, etc. Each layer is corroded. This is not limited to Cl, and the same applies when a halogen-based gas plasma is used in this step. After this step, the stacked body 440 is carried into the plasma processing chamber 107.

"Plasma treatment (St5)"
The stacked body 440 is subjected to plasma processing in the plasma processing chamber 107 to remove the etching residual component. Specifically, H ₂ O gas is introduced into the plasma introduction pipe 306 from the gas introduction system 304 (see FIG. 6), and the gas is converted into plasma by microwaves or the like emitted from the plasma source 305. The flow rate of H ₂ O gas can be 500 sccm, the pressure can be 300 Pa, the microwave discharge power can be 2000 W, and the plasma treatment time can be 60 seconds. The generated plasma is applied to the laminate 440 through the plasma introduction pipe 306. At the same time, the laminate 440 is heated to a predetermined temperature by the heater 302. The heating temperature of the stacked body 440 can be 200 ° C.

  Thereby, the etching residual component adhering to the laminated body 440 causes a chemical reaction. For example, HCl is generated when the Cl component remains as described above. Similarly, when the Br component remains, HBr, HI for the I component, and HF for the F component are generated. These hydrogen halides have volatility, and since the plasma processing chamber 107 is depressurized, the stacked body 440 is further heated by the heater 302, so that it quickly volatilizes.

  The laminated body 440 is patterned as described above, and the magnetoresistive element 410 shown in FIG. 2 is manufactured from the laminated body 440. Since the etching residual component is removed by the plasma treatment process as described above, the occurrence of corrosion (after-corrosion) due to the etching residual component of the magnetoresistive element 410 can be prevented.

  The present invention is not limited to this embodiment, and can be modified within the scope not departing from the gist of the present invention.

  The magnetoresistive element that can be manufactured by the manufacturing method shown in each of the above embodiments is not limited to the one having the above-described structure, and can be appropriately changed.

  In order to confirm the influence of the presence or absence of the plasma treatment process, the following measurements were performed. A laminate similar to the laminate according to the first embodiment was produced, and etching and plasma treatment were performed according to the patterning method according to the first embodiment. The residual Cl component was measured by EPMA (Electron Probe Micro Analyzer) with respect to the produced magnetoresistive element. As a result, the count number of characteristic X-rays of Cl was about 100 counts. This was about the background, and it was confirmed that no Cl component remained.

  As a comparison, in the patterning method according to the first embodiment, a residual Cl component was measured by EPMA for a magnetoresistive element manufactured without performing plasma treatment. As a result, the count number of Cl characteristic X-rays exceeded 3000 counts, and it was confirmed that the Cl component remained. Therefore, it was found that the residual Cl component was effectively removed by the plasma treatment according to the above embodiment.

DESCRIPTION OF SYMBOLS 10 ... Magnetoresistive element 40 ... Laminated body 13 ... Pin layer (1st ferromagnetic layer)
14 ... Insulating layer 15 ... Free layer (second ferromagnetic layer)
DESCRIPTION OF SYMBOLS 100 ... Patterning apparatus 410 ... Magnetoresistive element 440 ... Laminated body 413 ... Pin layer (1st ferromagnetic layer)
414 ... Insulating layer 415 ... Free layer (second ferromagnetic layer)

Claims (5)

Forming a first ferromagnetic layer made of a ferromagnetic material on a substrate;
Forming an insulating layer made of magnesium oxide on the first ferromagnetic layer;
Forming a second ferromagnetic layer containing at least one of Fe and Co on the insulating layer;
Etching with a plasma containing a halogen-based element on a laminate in which the first ferromagnetic layer, the insulating layer, and the second ferromagnetic layer are laminated on the substrate,
Method for manufacturing a magneto-resistance element wherein exposing the laminate in H _{2 O} plasma is a plasma containing H _{2 O.} It is a manufacturing method of the magnetoresistive element according to claim 1,
In the step of exposing the stacked body to H ₂ O plasma, the stacked body is heated to 200 ° C. or more. A method of manufacturing a magnetoresistive element according to claim 1 or 2,
The _{H 2} O plasma, in addition to _{H 2 O H 2, He,} O 2, N 2, Ar, the method for manufacturing a magneto-resistance element is any plasma containing one or more Ne and Xe. Halogen system for a laminate in which a first ferromagnetic layer made of a ferromagnetic material, an insulating layer made of magnesium oxide, and a second ferromagnetic layer containing at least one of Fe and Co are laminated on a substrate. Etching with elemental plasma,
Method for manufacturing a magneto-resistance element wherein exposing the laminate in H _{2 O} plasma is a plasma containing H _{2 O.} An etching chamber for irradiating a processing object with plasma containing a halogen-based element;
A device for manufacturing a magnetoresistive element, comprising: a plasma processing chamber for irradiating the object to be processed with H ₂ O plasma which is plasma containing H ₂ O.

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