WO2006100779A1 - Dispositif a memoire magnetique et procede de fabrication - Google Patents

Dispositif a memoire magnetique et procede de fabrication Download PDF

Info

Publication number
WO2006100779A1
WO2006100779A1 PCT/JP2005/005390 JP2005005390W WO2006100779A1 WO 2006100779 A1 WO2006100779 A1 WO 2006100779A1 JP 2005005390 W JP2005005390 W JP 2005005390W WO 2006100779 A1 WO2006100779 A1 WO 2006100779A1
Authority
WO
WIPO (PCT)
Prior art keywords
film
layer
magnetic
memory device
magnetic memory
Prior art date
Application number
PCT/JP2005/005390
Other languages
English (en)
Japanese (ja)
Inventor
Chikako Yoshida
Osamu Shimizu
Original Assignee
Fujitsu Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Fujitsu Limited filed Critical Fujitsu Limited
Priority to PCT/JP2005/005390 priority Critical patent/WO2006100779A1/fr
Publication of WO2006100779A1 publication Critical patent/WO2006100779A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/01—Manufacture or treatment
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10B—ELECTRONIC MEMORY DEVICES
    • H10B61/00—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
    • H10B61/20—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices comprising components having three or more electrodes, e.g. transistors
    • H10B61/22—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices comprising components having three or more electrodes, e.g. transistors of the field-effect transistor [FET] type

Definitions

  • the present invention relates to a magnetic memory device and a manufacturing method thereof, and more particularly, to a magnetic memory device having a magnetoresistive element and a manufacturing method thereof.
  • MRAM Magnetic Random Access Memory
  • MRAM stores information using a combination of magnetization directions in two magnetic layers, and changes in resistance (i.e., current or current) when the magnetic directions between these magnetic layers are parallel and antiparallel. The stored information is read by detecting the voltage change).
  • MTJ Magnetic
  • Tunnel Junction A device called Tunnel Junction is known.
  • An MTJ element has two ferromagnetic layers stacked via a tunnel insulating film, and the tunnel current that flows through the tunnel insulating film is based on the relationship between the magnetic directions of the two ferromagnetic layers. It uses a changing phenomenon. That is, the MTJ element has a low element resistance (low resistance state) when the magnetic directions of the two ferromagnetic layers are parallel, and has a high element resistance (high resistance state) when the two ferromagnetic layers are antiparallel. By associating these two states with data “0” and data “1”, they can be used as a memory element.
  • FIG. 10 is a process cross-sectional view illustrating the proposed method of manufacturing a magnetic memory device.
  • a conductive layer 154, an antiferromagnetic layer 158, a fixed layer 166, a tunnel insulating film 168, a free layer 174, and a conductive layer 178 are sequentially formed on a substrate 110. .
  • a laminated film 179 including the conductive layer 154, the antiferromagnetic layer 158, the fixed layer 166, the tunnel insulating film 168, the free layer 174, and the conductive layer 178 is formed.
  • the conductive layer 154 serves as the lower electrode of the MTJ element 152
  • the conductive layer 176 serves as the upper electrode of the MTJ element 152.
  • a photoresist film 186 is formed on the conductive layer 178. Thereafter, the photoresist film 186 is patterned using photolithography technology.
  • the laminated film 179 is etched by argon ion milling using the photoresist film 186 as a mask until the surface of the conductive layer 154 is exposed. In this way, an MTJ element (magnetoresistance element) 152 is formed.
  • Patent Document 1 Japanese Patent Laid-Open No. 11-92971
  • Patent Document 2 JP 2002-76470 A
  • Patent Document 3 Japanese Patent Laid-Open No. 2003-31776
  • Patent Document 4 Japanese Patent No. 2677321
  • Patent Document 5 JP 2000-322710 A
  • Patent Document 6 Japanese Patent Laid-Open No. 2002-38285
  • Non-Patent Document 1 Noriyuki Fukumoto, Hideaki Numata, Katsumi Suemitsu, Seigo Nagahara, Norikazu Oshima, Hiromitsu Hata, Shuichi Tahara, Minoru Amano, Yoshiaki Asao, Hiroaki Kajita, ⁇ High heat resistance NiXFel-X / Al-oxide / Magnetization reversal characteristics of ferromagnetic tunnel junctions using Ta-free layers ", 28th Annual Meeting of the Japan Society of Applied Magnetics, 2004, p. 218
  • Non-Patent Document 2 GH Yu, HC Zhao, MH Li, and FW Zhu, "Interface reaction of Ta / Ni81Fel9or Ni81Fel9 / Ta and its suppression", Applied Physics Letters, Volume 80, Number 3, 21 January (2002), p . 455-457
  • the material of the laminated film 1 79 reattaches to the side surface of the etched laminated film 179, and the free layer 166 and the fixed layer 1 74 May be short-circuited.
  • the selectivity of the laminated film 179 with respect to the photoresist film 186 is not necessarily high enough, so that the photoresist film 186 must be formed very thick. I got it.
  • the photoresist film 186 has to be formed very thick has been an impediment to miniaturization of the magnetoresistive element.
  • the laminated film 179 is etched by ion milling, the sputtering speed varies depending on the incident angle of ions (depending on the incident angle of the sputtering rate), so the laminated film is etched perpendicular to the wafer surface. Is difficult. This has also been an impediment to miniaturization of magnetoresistive elements.
  • An object of the present invention is to provide a magnetic memory device capable of forming fine magnetoresistive elements with a high yield, and a method for manufacturing the same.
  • a magnetic memory device further comprising a film is provided.
  • a step of forming a first magnetic layer on a substrate, a step of forming a tunnel insulating film on the first magnetic layer, and the tunnel insulating film A step of forming a second magnetic layer thereon, a step of forming a ruthenium film on the second magnetic layer, a step of forming a conductive layer on the ruthenium film, and a photoresist mass on the conductive layer.
  • a method of manufacturing a magnetic memory device including a step of etching at least the ruthenium film and the second magnetic layer.
  • the ruthenium film since the ruthenium film is formed between the second magnetic layer and the electrode, the ruthenium film functions as an etching stopper when the electrode is formed by etching the conductive layer. Therefore, according to the present invention, it is possible to prevent receiving the second free layer damage when etching the conductive layer. Also, since the conductive layer is etched using the ruthenium film as an etching stopper, the patterning of the conductive layer can be performed uniformly in the wafer surface. Therefore, according to the present invention, the magnetoresistive element can be manufactured at a high yield. Can be formed.
  • the second magnetic layer and the like are patterned using the electrode as a mask, it is not necessary to form a very thick photoresist film. Since it is not necessary to form a very thick photoresist film, the photoresist film can be finely patterned. Therefore, according to the present invention, the magnetoresistive element can be formed finely.
  • the ruthenium film functions as an etching stopper, it is not necessary to detect the end point of etching using a plasma spectroscopic analyzer or the like. For this reason, according to the present invention, the conductive layer can be patterned easily and reliably.
  • the ruthenium film formed between the second magnetic layer and the electrode is subjected to heat treatment when aligning the spin direction in the first magnetic layer or the second magnetic layer. It also functions as a diffusion prevention film (barrier film) that prevents the atoms constituting the second magnetic layer and the atoms constituting the electrode from interdiffusion. Therefore, according to the present invention, the ruthenium film can prevent the atoms constituting the electrode and the atoms constituting the first magnetic layer from interdiffusion.
  • a magnetic memory device having a minute magnetoresistive element can be manufactured with a high yield.
  • FIG. 1 is a cross-sectional view showing a magnetic memory device according to an embodiment of the present invention.
  • FIG. 2 is a process sectional view showing the method for manufacturing the magnetic memory device according to the embodiment (part 2).
  • FIG. 3 is a process sectional view showing the method for manufacturing the magnetic memory device according to the embodiment (part 3).
  • FIG. 4 is a process sectional view showing the method for manufacturing the magnetic memory device according to the embodiment (part 4).
  • FIG. 5 is a process sectional view showing the method for manufacturing the magnetic memory device according to the embodiment (part 1).
  • FIG. 6 is a process sectional view showing the method for manufacturing the magnetic memory device according to the embodiment (part 6).
  • FIG. 7 is a graph (No. 1) showing a concentration profile in the depth direction obtained by Auger electron spectroscopy.
  • FIG. 8 is a graph (part 2) showing the concentration profile in the depth direction obtained by the Auger electron spectroscopy.
  • FIG. 9 is a graph showing a magnetic field curve measured by a sample vibration type magnetometer.
  • FIG. 10 is a process sectional view showing the proposed method for manufacturing a magnetic memory device.
  • FIG. 11 is a process cross-sectional view showing a case where a laminated film is etched by the RIE method. Explanation of symbols
  • the etched material of the laminated film 179 reattaches to the side surface of the laminated film 179, and the free layer 166 and the fixed layer 174 May be short-circuited.
  • the selectivity of the laminated film 179 with respect to the photoresist film 186 is not necessarily high enough, so that it is necessary to form the photoresist film 186 sufficiently thick. I got it. The fact that the photoresist film 186 had to be formed sufficiently thick was an obstacle to miniaturization of the magnetoresistive element.
  • the sputtering speed varies depending on the incident angle of ions (depending on the incident angle of the sputtering rate). Is difficult. This has also been an impediment to miniaturization of magnetoresistive elements.
  • etching of the laminated film using the RIE (Reactive Ion Etching) method is also considered.
  • FIG. 11 is a process cross-sectional view showing the case where the laminated film is etched by the RIE method.
  • a conductive layer 154, an antiferromagnetic layer 158, a fixed layer 166, a tunnel insulating film 168, a free layer 174, and a conductive layer 178 are sequentially formed on a substrate 110. .
  • a laminated film 179 including the conductive layer 154, the antiferromagnetic layer 158, the fixed layer 166, the tunnel insulating film 168, the free layer 174, and the conductive layer 178 is formed.
  • the conductive layer 154 serves as the lower electrode of the magnetoresistive element
  • the conductive layer 176 serves as the upper electrode of the magnetoresistive element.
  • a photoresist film 186 is formed on the conductive layer 178. Thereafter, the photoresist film 186 is patterned using photolithography technology.
  • the conductive layer 178 is etched by the RIE method using the photoresist film 186 as a mask.
  • the etching gas for example, a halogen-based gas is used. o In this way, an upper electrode made of the conductive layer 178 is formed.
  • the antiferromagnetic layer 158 is anisotropically etched.
  • a mixed gas of CO gas and NH gas is used as the etching gas.
  • the end point of etching is, for example, a plasma spectrometer
  • the material of the etched laminated film 179 reattaches to the sidewall of the laminated film 179, but does not adhere to the sidewall of the laminated film 179.
  • the kimono is removed as follows. That is, using a mixed gas of CO gas and NH gas
  • the laminated film 179 When the laminated film 179 is anisotropically etched, the laminated film 179 is etched in a direction substantially perpendicular to the substrate surface, and the lower electrode 154 functioning as an etching stopper is exposed. After the laminated film 179 is etched and the lower electrode 154 is exposed, the laminated film 179 that is a raw material of the deposit is not etched, so that the material of the laminated film 179 may be reattached to the side wall of the laminated film 179. Disappear. Deposits adhering to the side walls of the laminated film 179 are gradually removed by etching.
  • the laminated film 179 is etched using the RIE method, it is possible to prevent the free layer 174 and the fixed layer 166 from being short-circuited. Further, since the free layer 174 and the like are etched using the upper electrode 178 as a node mask, it is not necessary to form the photoresist film 186 very thick. Further, when the laminated film 179 is etched using the RIE method, the laminated film 179 can be etched almost perpendicularly to the wafer surface. Therefore, if the etching is performed using the RIE method, the magnetoresistive element 152 can be miniaturized.
  • the halide force generated during the etching is applied to the side wall of the upper electrode 178 and the surface of the free layer 174. It may adhere. If halogenated substances adhere to the side walls of the upper electrode 178 or the surface of the free layer 174, the adhered halogenated substances may react with the wiring material, resulting in corrosion of the wiring (after-corrosion). For this reason, it is difficult to form a magnetoresistive element with a sufficiently high yield.
  • the etching rate is not necessarily uniform within the wafer surface, it is not always easy to pattern the conductive layer 178 uniformly within the wafer surface.
  • the ruthenium film is formed between the free layer and the conductive layer (upper electrode), when the upper electrode is formed by etching the conductive layer, the ruthenium film is used as an etching stopper. It becomes possible to etch the layer. Therefore, the ruthenium film can prevent the free layer from being damaged by being exposed to the halogen-based gas used when etching the conductive layer. In addition, since the ruthenium film functions as an etching stopper when the conductive layer is etched to form the upper electrode, the conductive layer can be patterned uniformly. Therefore, according to the present embodiment, a magnetic memory device having a fine magnetic resistance element can be manufactured with a high yield.
  • the ruthenium film formed between the free layer and the conductive layer (upper electrode) is heat-treated while applying a magnetic field to align the spin direction in the fixed layer.
  • it also functions as a diffusion prevention film (barrier film) that prevents the atoms constituting the free layer and the atoms constituting the upper electrode from interdiffusion. Therefore, according to the present invention, it is possible to provide a magnetic memory device having a magnetoresistive element with better characteristics.
  • FIGS. 1-10 A magnetic memory device and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to FIGS.
  • FIG. 1 is a sectional view of the magnetic memory device according to the present embodiment.
  • Figure 1 (a) is according to this embodiment. It is sectional drawing which shows the structure of a magnetic memory device.
  • FIG. 1B is a cross-sectional view showing a part of the magnetic memory device according to the present embodiment.
  • a gate electrode (read word line) 14 is formed on a semiconductor substrate 10 via a gate insulating film 12.
  • the semiconductor substrate 10 for example, a silicon substrate is used.
  • source Z drain regions 16a and 16b are formed in the semiconductor substrate 10 on both sides of the gate electrode 14.
  • the transistor 18 having the gate electrode 14 and the source / drain regions 16a and 16b is formed.
  • An interlayer insulating film 20 is formed on the semiconductor substrate 10 on which the transistor 18 is formed.
  • contact holes 22 reaching the source Z drain regions 16a and 16b are formed.
  • a conductor plug 24 is embedded in the contact hole 22.
  • An interlayer insulating film 26 is formed on the interlayer insulating film 20 in which the conductor plugs 24 are embedded.
  • grooves 28a and 28b are formed in the interlayer insulating film 26 in the interlayer insulating film 26.
  • the groove 28a is for embedding the conductive layer 28a.
  • the groove 28b is for embedding the wiring 30b.
  • the upper surface of the conductor plug 24 is exposed in the grooves 28a and 28b.
  • a conductive layer 30a is embedded in the groove 28a.
  • the conductive layer 30a is connected to the conductor plug 24.
  • a wiring (ground line) 30b is embedded in the groove 28b.
  • Wiring 3 Ob functions as a ground line.
  • the ground line 30b is electrically connected to the source / drain region 16b of the transistor 18 through the conductor plug 24 !.
  • An interlayer insulating film 32 is formed on the interlayer insulating film 26 in which the conductive layer 30a and the wiring 30b are embedded.
  • a contact hole 34 reaching the conductive layer 30a is formed in the interlayer insulating film 32.
  • a conductor plug 36 is embedded in the contact hole 34. The conductor plug 36 is connected to the conductive layer 30a.
  • An interlayer insulating film 38 is formed on the interlayer insulating film 32 in which the conductor plugs 36 are embedded. Grooves 40 a and 40 b are formed in the interlayer insulating film 38. In the groove 40a, the upper surface of the conductor plug 36 is exposed!
  • a conductive layer 41a is embedded in the groove 40a.
  • the conductive layer 41a is connected to the conductor plug 36.
  • a wiring (write word line) 41b is embedded in the groove 40b.
  • the conductive layer 41 a and the write word line 41 b are each composed of a laminated film composed of a Ta (tantalum) film (not shown), a NiFe film 42, and a Cu (copper) film 44.
  • the Ta film functions as a barrier metal film.
  • the NiFe film 42 functions as a cladding layer for obtaining a strong magnetic field when writing.
  • An interlayer insulating film 46 having a film thickness of lOOnm is formed on the interlayer insulating film 38 in which the conductive layer 41a and the write word line 41b are embedded.
  • a contact hole 48 reaching the conductive layer 41a is formed in the interlayer insulating film 46.
  • a conductor plug 50 is embedded in the contact hole 48. The conductor plug 50 is electrically connected to the conductive layer 41a.
  • a lower electrode 54 of the magnetoresistive element 52 is formed on the interlayer insulating film 46 in which the conductor plug 50 is embedded.
  • a material of the lower electrode 54 for example, a Ta film is used.
  • the lower electrode 54 is electrically connected to the source / drain region 16a of the transistor 18 through the conductor plug 50, the conductive layer 41a, the conductor plug 36, the conductive layer 30a, and the conductor plug 24.
  • a NiFe film 56 is formed on the lower electrode 54.
  • the NiFe film 56 is for forming an antiferromagnetic layer 58 with good crystallinity on the upper side.
  • an antiferromagnetic layer 58 made of a PtMn film is formed on the NiFe film 56.
  • a ferromagnetic layer 60 made of a CoFe film is formed on the antiferromagnetic layer 58.
  • a nonmagnetic layer 62 made of a Ru film is formed on the ferromagnetic layer 60.
  • a ferromagnetic layer 64 made of a CoFe film is formed on the nonmagnetic layer 62.
  • the ferromagnetic layer 60, the nonmagnetic layer 62, and the ferromagnetic layer 64 constitute a fixed layer (first magnetic layer) 66 of the magnetoresistive element 52.
  • a tunnel insulating film 68 made of an alumina (AIO) film is formed on the fixed layer 66.
  • a ferromagnetic layer 70 made of an Fe film is formed on the tunnel insulating film 68.
  • a ferromagnetic layer 72 made of a NiFe film is formed on the ferromagnetic layer 70.
  • the ferromagnetic layer 70 and the ferromagnetic layer 72 constitute a free layer (second magnetic layer) 74 of the magnetoresistive element 52.
  • a Ru (ruthenium) film 76 is formed on the free layer 74. As will be described later, the Ru film 76 functions as an etching stopper film. The Ru film 76 will be described later. In other words, it also functions as a diffusion preventing film (barrier film).
  • An upper electrode (cap layer) 78 is formed on the Ru film 76.
  • a material of the upper electrode 78 for example, a Ta film is used.
  • the upper electrode 78 also functions as a hard mask when the free layer 76 and the like are etched.
  • a magnetoresistive element (MTJ element) 52 including the lower electrode 54, the antiferromagnetic layer 58, the fixed layer 66, the tunnel insulating film 68, the free layer 74, the Ru film 76, and the upper electrode 78 is formed.
  • An interlayer insulating film 80 is formed on the interlayer insulating film 46 on which the magnetoresistive element 52 is formed.
  • a contact hole 82 reaching the upper electrode 78 is formed in the interlayer insulating film 80.
  • a bit line 84 is formed in the contact hole 82 and on the interlayer insulating film 80.
  • the bit line 84 is connected to the upper electrode 78 of the magnetoresistive element 52.
  • the magnetic memory device according to the present embodiment is constituted.
  • the magnetic memory device according to the present embodiment is mainly characterized in that a Ru film 76 is formed between the free layer 74 and the upper electrode 78.
  • the Ru film 76 is formed between the free layer 74 and the upper electrode 78, the conductive layer 78 is etched to form the upper electrode, as will be described later.
  • the Ru film 76 functions as an etching stopper. Therefore, according to the present embodiment, it is possible to prevent the free layer 74 from being damaged when the conductive layer 78 is etched.
  • the conductive layer 78 is etched using the Ru film 76 as an etching stopper, the patterning of the conductive layer 78 can be performed uniformly in the wafer surface. Therefore, according to the present embodiment, the magnetoresistive element can be formed with a high yield.
  • the free layer 74 and the like are patterned using the upper electrode 78 as a mask, it is not necessary to form the photoresist film 86 very thickly. Since it is not necessary to form the photoresist film 86 very thickly, the photoresist film 86 can be finely patterned. Therefore, according to the present embodiment, the magnetoresistive element can be formed finely.
  • the Ru film 76 serves as an etching stopper. Therefore, it is not necessary to detect the end point of etching using a plasma spectroscopic analyzer or the like. Therefore, according to the present embodiment, the conductive layer 78 can be patterned easily and reliably.
  • the Ru film 76 formed between the free layer 74 and the upper electrode 78 is self-treated in the heat treatment when aligning the spin direction in the fixed layer 66 as described later. It also functions as a diffusion prevention film (noria film) that prevents mutual diffusion between the constituent atoms of the base layer 76 and the constituent atoms of the upper electrode 78. For this reason, according to the present embodiment, the Ru film 76 can prevent the atoms constituting the upper electrode 78 and the atoms constituting the free layer 76 from interdiffusion.
  • a magnetic memory device having a minute magnetoresistive element can be manufactured at a high yield.
  • FIGS. 2 to 6 are process cross-sectional views illustrating the method of manufacturing the magnetic memory device according to the present embodiment.
  • a transistor 18 having a gate electrode 14 and source Z drain regions 16a and 16b is formed on a semiconductor substrate 10.
  • the semiconductor substrate 10 For example, a silicon substrate is used.
  • an interlayer insulating film 20 made of a silicon oxide film having a thickness of lOOOnm is formed on the entire surface by, eg, CVD.
  • the surface of the interlayer insulating film 20 is planarized by, eg, CMP.
  • a contact hole 22 reaching the source Z drain regions 16a and 16b is formed in the interlayer insulating film 20 by using a photolithography technique.
  • a 30 nm-thickness Ti film (not shown) is formed on the entire surface by, eg, sputtering.
  • a TiN film (not shown) having a thickness of lOnm is formed on the entire surface by, eg, CVD.
  • a barrier metal film (not shown) made of a Ti film and a TiN film is formed.
  • a 300 nm-thickness tungsten film is formed on the entire surface by, eg, CVD.
  • the tungsten film and the barrier metal film are polished by, for example, a CMP method until the surface of the interlayer insulating film 20 is exposed.
  • the conductor plug 24 made of a tungsten film or the like is embedded in the contact hole 22.
  • an interlayer insulating film 26 made of a silicon oxide film having a thickness of 300 nm is formed on the entire surface by, eg, CVD.
  • the surface of the interlayer insulating film 26 is flattened by, eg, CMP.
  • trenches 28 a and 28 b are formed in the interlayer insulating film 26 by using a photolithography technique.
  • the groove 28b is for embedding the ground line 30b.
  • a seed layer (not shown) is formed on the entire surface by, eg, sputtering.
  • a 600 nm-thickness Cu film is formed on the entire surface by, eg, electroplating.
  • the Cu film and the seed layer are polished by, for example, a CMP method until the surface of the interlayer insulating film 26 is exposed.
  • the conductive layer 30a made of a Cu film or the like is buried in the groove 28a, and the ground line 30b made of the Cu film or the like is buried in the groove 28b.
  • an interlayer insulating film 32 made of a silicon oxide film having a thickness of 200 nm is formed on the entire surface by, eg, CVD.
  • the surface of the interlayer insulating film 32 is planarized by, eg, CMP.
  • a contact hole 34 reaching the conductive layer 30a is formed in the interlayer insulating film 32 by using a photolithography technique.
  • a 30 nm-thickness Ti film (not shown) is formed on the entire surface by, eg, sputtering.
  • a 20 nm-thick TiN film (not shown) is formed on the entire surface by, eg, CVD.
  • a barrier metal film (not shown) made of a Ti film and a TiN film is formed.
  • a 300 nm-thickness tungsten film is formed on the entire surface by, eg, CVD.
  • the tungsten film and the barrier metal film are polished by, eg, CMP method until the surface of the interlayer insulating film 32 is exposed.
  • the conductor plug 36 made of a tungsten film or the like is embedded in the contact hole 34.
  • an interlayer insulating film 38 made of a silicon oxide film having a thickness of 400 nm is formed on the entire surface by, eg, CVD.
  • the surface of the interlayer insulating film 38 is planarized by, eg, CMP.
  • grooves 40a and 40b are formed in the interlayer insulating film 38 by photolithography.
  • Oa is for embedding the conductive layer 41a.
  • the groove 40b is for embedding the write word line 41b.
  • a 20 nm-thickness Ta film (not shown) is formed on the entire surface by, eg, sputtering.
  • the Ta film functions as a noria metal film.
  • NiFe film 42 is formed on the entire surface by, eg, sputtering.
  • the NiFe film 42 functions as a clad layer for obtaining a strong magnetic field when writing.
  • a Cu film 44 having a film thickness of 800 nm is formed by an electroplating method.
  • the Cu film 44, the NiFe film 42, and the Ta film are polished by, for example, CMP until the surface of the interlayer insulating film 38 is exposed.
  • the conductive layer 4 la made of the Cu film 44 or the like is buried in the groove 40a, and the write word line 41b made of the Cu film 44 or the like is buried in the groove 40b.
  • an interlayer insulating film 46 is formed on the entire surface by, eg, CVD.
  • a contact hole 48 that reaches the conductive layer 41 a is formed in the interlayer insulating film 46 by using a photolithography technique.
  • a 30 nm-thick Ti film (not shown) is formed on the entire surface by, eg, sputtering.
  • a TiN film (not shown) having a thickness of 20 nm is formed by, eg, CVD.
  • a barrier metal film (not shown) made of a Ti film and a TiN film is formed.
  • a 300 nm-thickness tungsten film is formed by, eg, CVD.
  • the tungsten film and the barrier metal film are polished by CMP, for example, until the surface of the interlayer insulating film 46 is exposed. In this way, the conductor plug 50 made of tungsten or the like is embedded in the contact hole 48.
  • a conductive layer 54 made of a Ta film is formed on the entire surface by, eg, sputtering.
  • the conductive layer 54 becomes a lower electrode of the magnetoresistive element 52.
  • FIG. 3A the components existing below the interlayer insulating film 46 are omitted.
  • a NiFe film 56 having a thickness of 2 nm is formed by, eg, sputtering.
  • the NiFe film 56 is for forming an antiferromagnetic layer 58 with good crystallinity on the upper side.
  • an antiferromagnetic layer 58 made of a PtMn film having a thickness of 20 nm is formed by, eg, sputtering.
  • the ferromagnetic layer 60 made of a CoFe film having a thickness of 3 nm is formed by, eg, sputtering.
  • the nonmagnetic layer 62 made of a Ru film having a thickness of 0.9 nm is formed by, eg, sputtering.
  • the ferromagnetic layer 64 made of a CoFe film having a thickness of 3 nm is formed by, eg, sputtering.
  • the ferromagnetic layer 60, the nonmagnetic layer 62, and the ferromagnetic layer 64 constitute a fixed layer 66.
  • tunnel insulation made of lnm-thick alumina (AIO) is formed by, for example, sputtering.
  • a film 68 is formed.
  • a ferromagnetic layer 70 made of a CoFe film having a thickness of 2 nm is formed by, eg, sputtering.
  • a ferromagnetic layer 72 made of a NiFe film having a thickness of 4 nm is formed by, eg, sputtering.
  • the ferromagnetic layer 70 and the ferromagnetic layer 72 constitute a free layer 74.
  • a Ru (ruthenium) film 76 having a thickness of 1 nm is formed by, eg, sputtering.
  • the Ru film 76 functions as an etching stopper when the conductive layer 78 is patterned to form the upper electrode.
  • the Ru film 76 is heat-treated while applying a magnetic field to align the spin direction in the fixed layer 66, the atoms in the upper electrode 78 and the atoms in the free layer 74 are interdiffused. It also functions as a diffusion preventive film (nore film) that prevents this.
  • the conductive layer 78 made of a Ta film with a thickness of 30 nm is formed by, eg, sputtering.
  • the conductive layer 78 becomes an upper electrode. Further, as will be described later, the conductive layer 78 functions as a hard mask (cap layer) when the free layer 74 and the like are patterned.
  • a photoresist film 86 is formed on the entire surface by, eg, spin coating.
  • the photoresist film 86 is patterned using a photolithography technique (see FIG. 3B).
  • a photolithography technique see FIG. 3B.
  • it is exposed using an electron beam.
  • the conductive layer 78 is formed by the RIE (Reactive Ion Etching) method using the photoresist film 86 as a mask and the Ru film 76 as an etching stopper.
  • Etch As the etching apparatus, for example, an inductively coupled plasma (ICP) etching apparatus is used.
  • the inductively coupled plasma etching apparatus is a plasma etching apparatus using a high-density plasma generated by accelerating electrons by generating an induction electric field in plasma by a high frequency induction magnetic field generated by an antenna.
  • the etching conditions are as follows, for example.
  • Halogen gas is used as the etching gas. More specifically, a mixed gas of halogen gas and Ar gas is used.
  • C1 gas is used as the halogen-based gas. C1 gas flow
  • the amount is, for example, 20 sccm.
  • the flow rate of Ar gas is, for example, 17 sccm.
  • the pressure in the chamber when performing etching is, for example, 0.7 Pa.
  • the power applied to the upper electrode of the etching apparatus is 800 W, for example.
  • the power applied to the lower electrode of the etching apparatus is 60 W, for example.
  • the etching time is 20 seconds, for example.
  • the conductive layer 78 is patterned by etching for about 15 seconds. One bar etch is performed. The over-etching is performed in order to pattern the conductive layer 78 uniformly in the wafer surface.
  • the Ru film 76 functions as an etching stopper when the conductive layer 78 is etched, the conductive layer 78 can be uniformly patterned in the wafer surface. Further, since the selection ratio of the conductive layer 78 to the Ru film 78 is sufficiently high, even the Ru film 76 is not etched when the conductive layer 78 is etched. Therefore, the Ru film 76 can prevent the free layer 74 from being damaged when the conductive layer 78 is etched.
  • the material of the conductive layer 78 is not limited to the Ta film.
  • a Ti film or a TiN film may be used as the material for the conductive layer 78.
  • the conductive layer 78 can be etched with a high selectivity with respect to the Ru film 76.
  • halogen-based gas is not limited to the C1 gas.
  • halogen-based gas is not limited to the C1 gas.
  • halogen-based gas is not limited to the C1 gas.
  • CF gas or the like may be used. Even when CF gas is used,
  • the conductive layer 78 can be etched at a high selectivity.
  • the material of the conductive layer 78, the etching gas, and the like may be appropriately set so that the conductive layer 78 can be etched with a high selection ratio with respect to the Ru film 76.
  • the upper electrode made of the conductive layer 78 is formed.
  • the upper electrode 78 also functions as a hard mask when the free layer 74 and the like are etched.
  • the upper electrode 78 is used as a node mask
  • the conductive layer 54 is used as an eztin dust flange
  • a Ru film 76 is used as an eztin dust flange
  • a free layer 74 is used as an eztin dust flange
  • a tunnel insulating film 68 is used as a fixed layer 66
  • the ferromagnetic layer 58 and the NiFe film 56 are etched.
  • the etching conditions are as follows.
  • As the etching gas for example, a mixed gas of CO gas and NH gas is used. CO gas flow rate
  • the conductive layer 54 is patterned using a photolithography technique. Thereby, a lower electrode made of the conductive layer 54 is formed.
  • an interlayer insulating film 80 made of a silicon oxide film is formed by a low temperature plasma CVD method.
  • the film formation temperature is, for example, 300 ° C or lower.
  • the surface of the interlayer insulating film 80 is planarized by CMP.
  • a contact hole 82 reaching the upper electrode 78 is formed by using a photolithography technique.
  • the direction of spin in the fixed layer 66 is aligned by performing heat treatment while applying a magnetic field.
  • the heat treatment temperature is, for example, 260 ° C.
  • the strength of the magnetic field is 2T, for example. Since the Ru film 76 is formed between the free layer 74 and the upper electrode 78, even if such a heat treatment is performed, the atoms in the free layer 74 and the atoms in the upper electrode 78 are interdiffused.
  • a conductive layer 84 made of, eg, aluminum is formed on the entire surface by, eg, sputtering.
  • the conductive layer 84 is patterned using a photolithography technique. Thus, a bit line made of the conductive layer 84 is formed. The bit line 84 is electrically connected to the upper electrode of the magnetoresistive element.
  • the magnetic memory device according to the present embodiment is manufactured.
  • the main feature is that the Ru film 76 is formed between the free layer 74 and the conductive layer 78.
  • the Ru film 76 is formed between the free layer 74 and the upper electrode 78. Therefore, when the upper electrode is formed by etching the conductive layer 78, the Ru film 76 is etched. Functions as a stock. Therefore, according to the present embodiment, it is possible to prevent the free layer 74 from being damaged when the conductive layer 78 is etched. In addition, since the conductive layer 78 is etched using the Ru film 76 as an etch stopper, the patterning of the conductive layer 78 can be performed uniformly in the wafer surface. Therefore, according to the present embodiment, the magnetic resistance element can be formed with a high yield.
  • the free layer 74 and the like are patterned using the upper electrode 78 as a mask, it is not necessary to form the photoresist film 86 very thickly. Since it is not necessary to form the photoresist film 86 very thickly, the photoresist film 86 can be finely patterned. Therefore, according to the present embodiment, the magnetoresistive element can be formed finely. Further, according to the present embodiment, as will be described later, since the Ru film 76 functions as an etching stopper, it is not necessary to detect the etching end point using a plasma spectroscopic analyzer or the like. Therefore, according to the present embodiment, the conductive layer 78 can be patterned easily and reliably.
  • the Ru film 76 formed between the free layer 74 and the upper electrode 78 is formed by the constituent atoms of the free layer 76 in the heat treatment when aligning the spin direction in the fixed layer 66. It also functions as a diffusion prevention film (barrier film) that prevents mutual diffusion between the upper electrode 78 and the constituent atoms of the upper electrode 78. Therefore, according to the present embodiment, the Ru film 76 can prevent the atoms constituting the upper electrode 78 and the atoms constituting the free layer 76 from interdiffusion.
  • a magnetic memory device having a fine magnetoresistive element can be manufactured at a high yield.
  • the AES method is a method for identifying and quantifying elements on the surface of a sample by irradiating a solid surface with an electron beam and measuring the electron energy distribution emitted by the Auge transition.
  • the analysis was performed while sputtering the surface of the laminated film.
  • the horizontal axis indicates the sputtering time, and the vertical axis indicates the atomic concentration.
  • FIG. 7 shows the case of the present embodiment, that is, the case where the Ta film is formed on the NiFe film via the Ru film.
  • the thickness of the NiFe film was 10 nm.
  • the film thickness of the Ru film was lnm.
  • the thickness of the Ta film was 30 nm.
  • the dotted line in Fig. 7 shows the case of analysis by AES method without heat treatment.
  • the solid line in Fig. 7 shows the case of analysis by AES method after heat treatment at 330 ° C for 30 minutes.
  • FIG. 8 shows the case of the comparative example, that is, the case where the Ta film without forming the Ru film is directly formed on the NiFe film.
  • the thickness of the NiFe film was 10 nm.
  • the thickness of the Ta film was 30 nm.
  • the dotted line in Fig. 8 shows the case of analysis by AES method without heat treatment.
  • the solid line in Fig. 8 shows the case of analysis by AES after heat treatment at 330 ° C for 30 minutes.
  • the laminated film is obtained by performing heat treatment.
  • the Ta concentration in the vicinity of the surface becomes lower.
  • the Ni concentration in the vicinity of the surface of the laminated film is increased by performing the heat treatment. From these, it can be seen that in the case of the comparative example, the atoms constituting the NiFe film and the atoms constituting the Ta film are mutually diffused by heat treatment.
  • the atoms constituting the free layer 76 and the atoms constituting the upper electrode 78 are mutually diffused in the heat treatment for aligning the spin direction in the fixed layer 66. It can be seen that the Ru film 76 can prevent this.
  • FIG. 9 is a graph showing a magnetization curve (Magnetization Curve) measured by a sample vibration magnetometer (VSM).
  • VSM sample vibration magnetometer
  • the horizontal axis indicates the external magnetic field
  • the vertical axis indicates the magnetic field.
  • the thin solid line shows the case of the comparative example, that is, the case where the Ta film is formed directly on the NiFe film without forming the Ru film.
  • the thick solid line shows the case of the present embodiment, that is, the case where the Ta film is formed on the NiFe film via the Ru film.
  • the saturation magnetization is increased by about 15% compared to the comparative example.
  • a magnetoresistive element having good characteristics can be formed.
  • such good characteristics can be obtained because the atoms constituting the free layer 76 and the atoms constituting the free layer 76 are subjected to heat treatment when aligning the spin direction in the fixed layer 66. This is because the Ru film 76 can prevent the atoms constituting the upper electrode 78 from interdiffusion.
  • the case where the antiferromagnetic layer 58, the fixed layer 66, the tunnel insulating film 68, and the free layer 74 are sequentially stacked on the lower electrode 54 has been described as an example.
  • the laminated structure of 52 is not limited to this.
  • the free layer 74, the tunnel insulating film 68, the fixed layer 66, and the antiferromagnetic layer 58 may be sequentially stacked on the lower electrode 54.
  • a Ru film 76 may be formed between the antiferromagnetic layer 58 and the upper electrode 78.
  • the case where the upper electrode 78 remains on the Ru film 76 has been described as an example. However, after patterning the free layer 74 and the like, the upper electrode 78 is polished and removed. May be. In this case, the bit line 84 also serves as the upper electrode of the magnetoresistive element 52. In this case, it is preferable that the Ru film 76 be formed thick so that when the upper electrode 78 is removed by polishing, even the Ru film 76 is removed and the free layer 74 is not damaged.
  • the Ru film 76 and the mixed gas of CO gas and NH gas are used.
  • the etching gas used for etching the Ru film 76 and the free layer 74 and the like is not limited thereto.
  • the etching gas use methanol gas as the etching gas. Even when methanol gas is used, it is possible to etch the Ru film 76, the free layer 74, and the like with a high selectivity.
  • the material of the free layer 74 is not limited to the CoFe film or the NiFe film.
  • Any magnetic material that can be etched at a high selectivity with respect to the upper electrode 78 can be used as the material of the free layer 74 as appropriate.
  • a magnetic material containing at least one of Co (cobalt), Fe (iron), and Ni (nickel) can be used as the material of the free layer 74.
  • the material of the fixed layer 66 is not limited to the CoFe film or the like. Any magnetic material that can be etched at a high selectivity with respect to the upper electrode 78 is used as the material of the fixed layer 66. It can be used as appropriate. For example, a magnetic material containing at least one of Co, Fe, and Ni can be used as the material of the fixed layer 66.
  • the material of the antiferromagnetic layer 58 is not limited to the PtMn film. Any antiferromagnetic material that can be etched at a high selectivity with respect to the upper electrode 78 can be appropriately used as the material of the antiferromagnetic layer 58.
  • an IrMn (Ir: iridium, Mn: manganese) film may be used as the material of the antiferromagnetic layer 58.
  • the material of the tunnel insulating film 68 is not limited to the alumina film. Any insulating material that can be etched with a high selectivity with respect to the upper electrode 78 can be used as the material of the tunnel insulating film 68 as appropriate.
  • MgO Mg: Magnesium
  • HfO Hf: Hafnium
  • HfAlO A1: Aluminum
  • TiO etc.
  • edge film 68 It can also be used as a material for the edge film 68.
  • the magnetic memory device and the manufacturing method thereof according to the present invention are useful for manufacturing a magnetic memory device having fine magnetoresistive elements with a high yield.

Abstract

La présente invention concerne un dispositif à mémoire magnétique muni d’une première couche magnétique (66) formée sur un substrat (10) ; un film isolant tunnel (68) formé sur la première couche magnétique (66) ; une seconde couche magnétique (74) formée sur le film isolant tunnel (68) ; et un élément de résistance magnétique (52) comportant une électrode (78) formée sur la seconde couche magnétique (74). En outre, le dispositif à mémoire magnétique est muni d’un film au ruthénium (76) formé entre la seconde couche magnétique (74) et l’électrode (78). Etant donné que le film au ruthénium est formé entre la seconde couche magnétique et l’électrode, il sert à arrêter l’attaque chimique au moment de la formation de l’électrode par l’attaque chimique d’une couche conductrice. Le film au ruthénium formé entre la seconde couche magnétique et l’électrode fonctionne également comme un film empêchant la diffusion destiné à empêcher la diffusion mutuelle d’atomes composant la seconde couche magnétique et d’atomes composant l’électrode, dans le traitement à chaud pour correspondre à des directions de rotation dans la première couche magnétique ou la seconde couche magnétique. En conséquence, ledit dispositif comportant un élément de résistance magnétique fin peut être facturé avec un rendement élevé.
PCT/JP2005/005390 2005-03-24 2005-03-24 Dispositif a memoire magnetique et procede de fabrication WO2006100779A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP2005/005390 WO2006100779A1 (fr) 2005-03-24 2005-03-24 Dispositif a memoire magnetique et procede de fabrication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2005/005390 WO2006100779A1 (fr) 2005-03-24 2005-03-24 Dispositif a memoire magnetique et procede de fabrication

Publications (1)

Publication Number Publication Date
WO2006100779A1 true WO2006100779A1 (fr) 2006-09-28

Family

ID=37023476

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2005/005390 WO2006100779A1 (fr) 2005-03-24 2005-03-24 Dispositif a memoire magnetique et procede de fabrication

Country Status (1)

Country Link
WO (1) WO2006100779A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110896126A (zh) * 2018-09-13 2020-03-20 东芝存储器株式会社 磁存储装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1192971A (ja) * 1997-09-22 1999-04-06 Natl Res Inst For Metals 反応性イオンエッチング用のマスク
JP2004319725A (ja) * 2003-04-16 2004-11-11 Fujitsu Ltd 磁気ランダムアクセスメモリ装置
JP2005050907A (ja) * 2003-07-30 2005-02-24 Toshiba Corp 磁気抵抗効果素子および磁気メモリ
JP2005072491A (ja) * 2003-08-27 2005-03-17 Sony Corp ドライエッチング方法及び磁気メモリ装置の製造方法
JP2005085821A (ja) * 2003-09-04 2005-03-31 Toshiba Corp 磁気抵抗効果素子及び磁気メモリ

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1192971A (ja) * 1997-09-22 1999-04-06 Natl Res Inst For Metals 反応性イオンエッチング用のマスク
JP2004319725A (ja) * 2003-04-16 2004-11-11 Fujitsu Ltd 磁気ランダムアクセスメモリ装置
JP2005050907A (ja) * 2003-07-30 2005-02-24 Toshiba Corp 磁気抵抗効果素子および磁気メモリ
JP2005072491A (ja) * 2003-08-27 2005-03-17 Sony Corp ドライエッチング方法及び磁気メモリ装置の製造方法
JP2005085821A (ja) * 2003-09-04 2005-03-31 Toshiba Corp 磁気抵抗効果素子及び磁気メモリ

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110896126A (zh) * 2018-09-13 2020-03-20 东芝存储器株式会社 磁存储装置
CN110896126B (zh) * 2018-09-13 2024-04-09 铠侠股份有限公司 磁存储装置

Similar Documents

Publication Publication Date Title
US7476329B2 (en) Methods for contacting conducting layers overlying magnetoelectronic elements of MRAM devices
US7358553B2 (en) System and method for reducing shorting in memory cells
US7247506B2 (en) Method for producing magnetic memory device
US7045368B2 (en) MRAM cell structure and method of fabrication
US7864569B2 (en) Structure of magnetic random access memory using spin-torque transfer writing
US20060220084A1 (en) Magnetoresistive effect element and method for fabricating the same
US7808026B2 (en) Dry etching method and production method of magnetic memory device
US20090078927A1 (en) Composite hard mask for the etching of nanometer size magnetic multilayer based device
US7279341B2 (en) Method for fabricating a flux concentrating system for use in a magnetoelectronics device
US7144744B2 (en) Magnetoresistive random access memory device structures and methods for fabricating the same
CN103794717A (zh) 一种包含介电层的嵌入型磁隧道结器件的制造方法
KR102553611B1 (ko) 자기 터널 접합부의 이온 빔 에칭을 위한 후처리 프로세스 및 이에 의해 형성된 구조물
US7169622B2 (en) Magnetoresistive random access memory devices and methods for fabricating the same
KR102354657B1 (ko) 유전체 계면 층을 갖는 sot mram 및 그 형성 방법
US6806127B2 (en) Method and structure for contacting an overlying electrode for a magnetoelectronics element
US20220359820A1 (en) Method for forming mtjs with lithography-variation independent critical dimension
WO2006100779A1 (fr) Dispositif a memoire magnetique et procede de fabrication
JP2006165031A (ja) トンネル接合素子の製造方法およびその製造装置
CN109994476B (zh) 一种制备磁性随机存储器阵列单元的方法
JP2006173166A (ja) 磁気記憶装置の製造方法
JP2005159240A (ja) 磁気メモリ及びその製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

NENP Non-entry into the national phase

Ref country code: RU

WWW Wipo information: withdrawn in national office

Country of ref document: RU

122 Ep: pct application non-entry in european phase

Ref document number: 05721404

Country of ref document: EP

Kind code of ref document: A1

WWW Wipo information: withdrawn in national office

Ref document number: 5721404

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: JP