WO2017183263A1 - Corps fritté d'oxyde, cible de pulvérisation et leurs procédés de fabrication - Google Patents

Corps fritté d'oxyde, cible de pulvérisation et leurs procédés de fabrication Download PDF

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Publication number
WO2017183263A1
WO2017183263A1 PCT/JP2017/004821 JP2017004821W WO2017183263A1 WO 2017183263 A1 WO2017183263 A1 WO 2017183263A1 JP 2017004821 W JP2017004821 W JP 2017004821W WO 2017183263 A1 WO2017183263 A1 WO 2017183263A1
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Prior art keywords
sintered body
oxide sintered
atomic
sintering
less
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PCT/JP2017/004821
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English (en)
Japanese (ja)
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幸樹 田尾
中根　靖夫
英雄 畠
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株式会社コベルコ科研
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Priority claimed from JP2017007850A external-priority patent/JP6254308B2/ja
Application filed by 株式会社コベルコ科研 filed Critical 株式会社コベルコ科研
Priority to CN201780023775.2A priority Critical patent/CN109071361B/zh
Priority to KR1020187029670A priority patent/KR102091554B1/ko
Priority to US16/092,400 priority patent/US20190177230A1/en
Publication of WO2017183263A1 publication Critical patent/WO2017183263A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/453—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering

Definitions

  • the present disclosure relates to an oxide sintered body used when a thin film transistor (TFT, Thin Film Transistor) oxide semiconductor thin film used in a display device such as a liquid crystal display or an organic EL display is formed by a sputtering method, and a sputtering target. , As well as their manufacturing method.
  • TFT Thin Film Transistor
  • the amorphous (amorphous) oxide semiconductor thin film used for TFT has higher carrier mobility, larger optical band gap, and can be formed at a lower temperature than general-purpose amorphous silicon (a-Si). Therefore, it is expected to be used in next-generation displays that require large size, high resolution and high-speed driving, and applied on a resin substrate with low heat resistance.
  • a-Si general-purpose amorphous silicon
  • an In-containing amorphous oxide semiconductor has been proposed.
  • an In—Ga—Zn-based oxide semiconductor has attracted attention.
  • a sputtering method of sputtering a sputtering target made of a material having the same composition as the thin film (hereinafter also referred to as “target material”) is preferably used.
  • Patent Document 1 discloses a target material made of an In—Ga—Zn—Sn-based oxide sintered body, in which the ratio of the InGaZn 2 O 5 phase is controlled to 3% or less as a main phase.
  • Patent Document 2 discloses a target material made of an In—Ga—Sn-based oxide sintered body, in which the ratio of the InGaO 3 phase is controlled to 0.05% or more.
  • Patent Document 3 is a target material made of an In—Ga—Sn-based oxide sintered body, in which the proportion of the Ga 3 InSn 5 O 16 phase is controlled to 0.02% or more and 0.2% or less. It is disclosed.
  • Patent Document 4 is a target material made of an In—Ga—Sn-based oxide sintered body, in which the proportion of the Ga 3 InSn 5 O 16 phase is controlled to 0.02% or more and 0.2% or less. It is disclosed.
  • JP 2014-58415 A Japanese Patent Laying-Open No. 2015-127293 JP 2015-166305 A JP2011-252231A
  • the target material of the In—Ga—Zn—Sn-based oxide sintered body is disclosed in Patent Document 1, but when the content of each element in the target material is different from that of Patent Document 1, Even if the ratio of the InGaZn 2 O 5 phase is controlled to 3% or less, there are cases where cracking of the target cannot be suppressed.
  • An embodiment of the present invention has been made in view of the above circumstances, and a first object is to use In—Ga for use in a sputtering target suitable for manufacturing an In—Ga—Zn—Sn-based oxide semiconductor thin film.
  • -Zn-Sn-based oxide sintered body which provides an oxide sintered body that can suppress the occurrence of cracking when bonded to a backing plate for an oxide sintered body containing a specific amount of each element That is.
  • the second object of the embodiment of the present invention is to provide a method for producing the above-described oxide sintered body.
  • the third object of the embodiment of the present invention is to provide a sputtering target using the above-described oxide sintered body.
  • the fourth object of the embodiment of the present invention is to provide a method for manufacturing a sputtering target.
  • the ratio (atomic%) of zinc, indium, gallium, and tin to all the metal elements excluding oxygen is [Zn] [In], [Ga], respectively. ] And [Sn] 40 atomic% ⁇ [Zn] ⁇ 55 atomic%, 20 atomic% ⁇ [In] ⁇ 40 atomic%, 5 atomic% ⁇ [Ga] ⁇ 15 atomic%, and 5 atomic% ⁇ [Sn] ⁇ 20 atomic% Satisfied, The relative density is 95% or more, As a crystal phase, InGaZn 2 O 5 is contained at 5 to 20% by volume.
  • the maximum equivalent circle diameter of the pores in the oxide sintered body is preferably 3 ⁇ m or less.
  • the relative ratio of the average equivalent circle diameter to the maximum equivalent circle diameter of the pores in the oxide sintered body is preferably 0.3 or more and 1.0 or less.
  • the oxide sintered body further contains InGaZn 3 O 6 as a crystal phase in an amount of more than 0% by volume and 10% by volume or less.
  • the oxide sintered body preferably has a crystal grain size of 20 ⁇ m or less, and particularly preferably a crystal grain size of 5 ⁇ m or less.
  • the oxide sintered body preferably has a specific resistance of 1 ⁇ ⁇ cm or less.
  • the sputtering target according to the embodiment of the present invention is formed by fixing the oxide sintered body on a backing plate with a bonding material.
  • a method for producing an oxide sintered body includes: Preparing a mixed powder containing zinc oxide, indium oxide, gallium oxide and tin oxide in a predetermined ratio; Sintering the mixed powder into a predetermined shape.
  • the sintering step may include holding the mixed powder at a sintering temperature of 900 to 1100 ° C. for 1 to 12 hours in a state where a surface pressure of 10 to 39 MPa is applied to the mixed powder with a molding die. At this time, in the step of sintering, it is preferable that an average rate of temperature increase up to the sintering temperature is 600 ° C./hr or less.
  • the manufacturing method further includes a step of preforming the mixed powder after the step of preparing the mixed powder and before the step of sintering.
  • the sintering step may include maintaining the preformed molded body at a sintering temperature of 1450 to 1550 ° C. for 1 to 5 hours under normal pressure. At this time, in the step of sintering, it is preferable that an average rate of temperature increase up to the sintering temperature is 100 ° C./hr or less.
  • the sputtering target according to the embodiment of the present invention includes a step of bonding the oxide sintered body or the oxide sintered body manufactured by the manufacturing method to a backing plate with a bonding material.
  • an oxide sintered body capable of suppressing the occurrence of cracks when bonded to a backing plate, a sputtering target using the oxide sintered body, and an oxide sintered body and a sputtering target. It is possible to provide a manufacturing method.
  • FIG. 1 is a schematic cross-sectional view of a sputtering target according to an embodiment of the present invention.
  • FIG. 2 is a secondary electron image of the oxide sintered body.
  • the oxide sintered body according to the embodiment of the present invention includes oxides of zinc, indium, gallium, and tin.
  • the content of the metal element contained in the oxide sintered body used for the sputtering target, and the crystal phase It is necessary to appropriately control the content rate.
  • the oxide sintered body of the embodiment of the present invention is When the content ratio (atomic%) of zinc, indium, gallium and tin with respect to all metal elements excluding element is [Zn] [In], [Ga] and [Sn], respectively. 40 atomic% ⁇ [Zn] ⁇ 55 atomic%, 20 atomic% ⁇ [In] ⁇ 40 atomic%, 5 atomic% ⁇ [Ga] ⁇ 15 atomic%, and 5 atomic% ⁇ [Sn] ⁇ 20 atomic% Satisfied, The relative density is 95% or more, As a crystal phase, InGaZn 2 O 5 is contained at 5 to 20% by volume.
  • the “all metal elements excluding oxygen contained in the oxide sintered body” are zinc, indium, gallium, and tin, and may further contain metal impurities inevitable in production.
  • the inevitable amount of metal impurities is very small, the influence on defining the ratio of the metal elements in the oxide sintered body is small. Therefore, “all metal elements excluding oxygen contained in the oxide sintered body” are substantially zinc, indium, gallium and tin.
  • the content of zinc, indium, gallium and tin in the oxide sintered body is expressed by the number of atoms, and the zinc content relative to the total amount (total number of atoms) is “[Zn]”.
  • the indium content is “[In]”
  • the gallium content is “[Ga]”
  • the tin content is “[Sn]”.
  • [Zn] + [In] + [Ga] + [Sn] 100 atomic%.
  • each element of zinc, indium, gallium and tin The content (atomic%) of each element of zinc, indium, gallium and tin will be described in detail below. Note that the content of each element is set mainly in consideration of the characteristics of the oxide semiconductor thin film formed using a sputtering target.
  • Zinc content 40 atomic% ⁇ [Zn] ⁇ 55 atomic% Zinc improves the stability of the amorphous structure of the oxide semiconductor thin film.
  • the zinc content is preferably 42 atomic% ⁇ [Zn] ⁇ 54 atomic%, more preferably 44 atomic% ⁇ [Zn] ⁇ 53 atomic%.
  • Indium content 20 atomic% ⁇ [In] ⁇ 40 atomic% Indium increases the carrier mobility of the oxide semiconductor thin film.
  • the indium content is preferably 21 atomic% ⁇ [In] ⁇ 39 atomic%, and more preferably 22 atomic% ⁇ [In] ⁇ 38 atomic%.
  • Gallium content 5 atomic% ⁇ [Ga] ⁇ 15 atomic% Gallium improves the light stress reliability of the oxide semiconductor thin film, that is, the threshold bias shift.
  • the content of gallium is preferably 6 atomic% ⁇ [Ga] ⁇ 14 atomic%, more preferably 7 atomic% ⁇ [Ga] ⁇ 13 atomic%.
  • Tin content 5 atomic% ⁇ [Sn] ⁇ 20 atomic% Tin improves the etchant resistance of the oxide semiconductor thin film.
  • the tin content is preferably 6 atomic% ⁇ [Sn] ⁇ 22 atomic%, and more preferably 7 atomic% ⁇ [Sn] ⁇ 20 atomic%.
  • [Sn] / [Ga] more than 0.5, less than 2.5 [Sn] / [Ga] is an index of the content of InGaZn 3 O 6 .
  • [Sn] / [Ga] is preferably more than 0.5 and less than 2.5.
  • InGaZn 3 O 6 exceeds 20% by volume, and when [Sn] / [Ga] is 2.5 or more, InGaZn 3 O 6 is 0 volume. %.
  • the oxide sintered body includes oxides of zinc, indium, gallium and tin. Specifically, it contains Zn 2 SnO 4 phase, InGaZnO 4 phase, InGaZn 2 O 5 phase, InGaZn 3 O 6 phase, In 2 O 3 phase and SnO 2 phase as constituent phases. Further, it may contain impurities such as oxides inevitably mixed or generated in production. In particular, in the embodiment of the present invention, cracking of the oxide sintered body can be effectively suppressed by containing the InGaZn 2 O 5 phase at a predetermined ratio.
  • the ratio of the crystal phase can be obtained by analyzing the X-ray diffraction spectrum of the oxide sintered body.
  • X-ray diffraction on the premise that the above-described crystal phases (that is, Zn 2 SnO 4 phase, InGaZnO 4 phase, InGaZn 2 O 5 phase, InGaZn 3 O 6 phase, In 2 O 3 phase and SnO 2 phase) exist.
  • the spectral peaks are assigned to specific crystal planes of these six crystal phases.
  • One peak is selected from a plurality of peaks assigned to each crystal phase, and the peak intensity of the selected peak is measured.
  • Six peak intensity measurements are obtained from the six crystal phases, and the six measurement values are converted to the strongest peak intensity of each crystal phase.
  • the ratio of the converted value of each crystal phase to the value (total value) obtained by summing the six converted values is determined.
  • This ratio is defined as the ratio of each crystal phase contained in the oxide crystal (content: volume%). That is, in this specification, when the converted values of the six peak intensities obtained from each crystal phase are totaled and the total value is taken as 100%, the ratio (%) of each converted value corresponding to each crystal phase, Used as the content (volume%) of each crystal phase.
  • the Zn 2 SnO 4 phase, the InGaZnO 4 phase, the InGaZn 2 O 5 phase, the InGaZn 3 O 6 phase, and the In 2 O 3 Only the phase and the SnO 2 phase are considered.
  • crystal phases other than the above-described crystal phases can be included, but the effect of the embodiment of the present invention (preventing cracking of the oxide sintered body) is not affected. Therefore, in the embodiment of the present invention, in order to obtain the effect of preventing cracking of the oxide sintered body, only the above six crystal phases are considered.
  • the content (volume%) of each crystal phase that can be included in the oxide sintered body will be described in detail. Note that the unit of the crystal phase content (volume%) may be simply expressed as “%”.
  • InGaZn 2 O 5 5 to 20% by volume InGaZn 2 O 5 has a pinning effect between crystal grains.
  • InGaZn 2 O 5 growth of the crystal grain size can be suppressed and the material strength can be increased, and cracking of the oxide sintered body when bonding to the backing plate can be suppressed.
  • the content of InGaZn 2 O 5 is less than 5% by volume, the material strength is not sufficient, and cracking of the oxide sintered body tends to occur. If the content exceeds 30% by volume, the specific resistance increases, and thus abnormal discharge may be induced. Therefore, by containing 5% by volume of InGaZn 2 O 5 , the effect of preventing cracking of the oxide sintered body can be sufficiently exhibited.
  • the content of InGaZn 2 O 5 is preferably 5 to 20% by volume, more preferably 5 to 15% by volume.
  • InGaZn 3 O 6 more than 0% by volume and ⁇ 10% by volume or less InGaZn 3 O 6 has a pinning effect between crystal grains like InGaZn 2 O 5 .
  • InGaZn 3 O 6 is included in addition to InGaZn 2 O 5 , the pinning effect can be further improved. Therefore, it is possible to further suppress cracking of the oxide sintered body when bonding to the backing plate.
  • InGaZn 3 O 6 is preferably contained in an amount of 0.5 to 8% by volume, more preferably 1 to 6% by volume.
  • the effect of suppressing cracking of the oxide sintered body can be improved by varying the range of the content ratio of the crystal phase depending on the ratio of the element content ratio.
  • preferable contents of Zn 2 SnO 4 , InGaZnO 4 and In 2 O 3 differ depending on the ratio of [Zn] / [In].
  • Zn 2 SnO 4 and In 2 O 3 have the effect of contributing to improvement of relative density and reduction of specific resistance.
  • the stability of discharge can be improved.
  • InGaZnO 4 has a pinning effect between crystal grains similarly to InGaZn 2 O 5 and InGaZn 3 O 6 . When InGaZnO 4 is included in addition to InGaZn 2 O 5 , the pinning effect can be further improved. Therefore, it is possible to further suppress cracking of the oxide sintered body when bonding to the backing plate.
  • [Zn] / [In] is less than 1.5, it is preferable to contain In 2 O 3 at 30% by volume or more.
  • the relative density of the oxide sintered body is preferably 95% or more. Thereby, the intensity
  • the relative density is more preferably 97% or more, and even more preferably 99% or more.
  • the relative density in this specification is calculated
  • FIG. 2 shows an example of a secondary electron image (magnification 1000 times) of the oxide sintered body.
  • black dot-like portions are pores. The pores can be easily distinguished from other metal structures in both SEM photographs and secondary electron images.
  • the pores in the oxide sintered body it is preferable that not only the porosity is low but also the pore size is small.
  • the molded body including pores is sintered, small pores disappear by sintering, but large pores do not disappear and remain inside the oxide sintered body.
  • the gas exists in a compressed state.
  • Sn, Ga, and the like in the molded body may be decomposed during sintering to generate pores inside the oxide sintered body. Compressed gas may also exist inside the pores thus generated. If pores containing a compressed gas are present in the oxide sintered body, the internal stress increases, and the mechanical strength and thermal shock resistance of the oxide sintered body are reduced.
  • the crack of the oxide sintered body due to the pores tends to be higher as the pores are larger. Therefore, by suppressing the size of the pores in the oxide sintered body, the mechanical strength of the oxide sintered body is increased, and cracking of the oxide sintered body can be suppressed.
  • the maximum equivalent circle diameter Dmax of the pores is 3 ⁇ m or less, the internal stress can be sufficiently reduced.
  • the maximum equivalent circle diameter of the porosity is more preferably 2 ⁇ m or less.
  • the relative ratio of the average equivalent circle diameter D ave ( ⁇ m) to the maximum equivalent circle diameter D max ( ⁇ m) of pores in the oxide sintered body is preferably 0.3 or more and 1.0 or less (that is, 0.3 ⁇ D ave / D max ⁇ 1.0).
  • the relative ratio is 1.0, the shape is circular. The smaller the relative ratio is, the flatter oval shape is.
  • the pores are elliptical, the mechanical strength is lowered and the oxide sintered body is easily cracked as compared to the case of a circular shape. In particular, the tendency becomes more prominent as the shape becomes a flat ellipse. Therefore, when the relative ratio is 0.3 or more, the strength of the oxide sintered body can be increased. More preferably, the relative ratio is 0.5 or more.
  • the maximum equivalent circle diameter and the average equivalent circle diameter of the pores in this specification are determined as follows. An oxide sintered body prepared as a measurement sample is cut in a thickness direction at an arbitrary position, and an arbitrary position of the cut surface is mirror-ground. Next, using a scanning electron microscope (SEM), photographs were taken at an appropriate magnification (for example, 1000 times magnification), and the equivalent circle diameters of all pores existing in a 100 ⁇ m square region were obtained. Similarly, the equivalent circle diameters of all pores were obtained at 20 cut surfaces in the same sample.
  • SEM scanning electron microscope
  • the largest equivalent circle diameter is defined as the “maximum equivalent circle diameter of pores” of the oxide sintered body, and the average value of all equivalent circle diameters is The oxide sintered body was defined as “the average equivalent circular diameter of pores”.
  • the average crystal grain size of the crystal grains is preferably 20 ⁇ m or less, whereby the effect of suppressing cracking of the oxide sintered body can be further improved.
  • the average crystal grain size is more preferably 10 ⁇ m or less, still more preferably 8 ⁇ m or less, and particularly preferably 5 ⁇ m.
  • the lower limit value of the average crystal grain size is not particularly limited, but a preferable lower limit of the average crystal grain size is about 0.05 ⁇ m from the balance between refinement of the average crystal grain size and production cost.
  • the average crystal grain size of the crystal grains is measured as follows. An oxide sintered body prepared as a measurement sample is cut in a thickness direction at an arbitrary position, and an arbitrary position of the cut surface is mirror-ground. Next, a photograph of the tissue on the cut surface is taken at a magnification of 400 using a scanning electron microscope (SEM). On the photograph taken, a straight line corresponding to a length of 100 ⁇ m is drawn in an arbitrary direction, and the number (N) of crystal grains existing on the straight line is obtained. The value calculated by [100 / N] ( ⁇ m) is defined as the “crystal grain size on a straight line”.
  • coarse crystal grains having a crystal grain size exceeding 30 ⁇ m cause cracking of the oxide sintered body at the time of bonding.
  • coarse crystal grains having a crystal grain size exceeding 30 ⁇ m are preferably in an area ratio of 10% or less, more preferably 8% or less, further preferably 6% or less, further preferably 4% or less, and most preferably 0%. .
  • the area ratio of crystal grains having a crystal grain size exceeding 30 ⁇ m is measured as follows.
  • a crystal grain having a length of 30 ⁇ m or more cut by the straight line is defined as a “coarse grain”.
  • L ( ⁇ m) the length occupied by the coarse particles (that is, the length of the portion of the straight line crossing the coarse particles)
  • R (%) of coarse particles on this straight line was defined as the ratio R (%) of coarse particles on this straight line.
  • R (%) (L ( ⁇ m) / 100 ( ⁇ m)) ⁇ 100 (%)
  • the ratio R (%) of the coarse particles is obtained.
  • the ratio R (%) of coarse grains was determined, and the average value was taken as the ratio of coarse grains of this sintered body.
  • the specific resistance of the oxide sintered body is preferably 1 ⁇ ⁇ cm or less, more preferably 10 ⁇ 1 ⁇ ⁇ cm or less, and further preferably 10 ⁇ 2 ⁇ ⁇ cm or less.
  • the oxide sintered body is fixed to a backing plate to form a sputtering target.
  • this sputtering target by suppressing the specific resistance of the oxide sintered body to a low level, abnormal discharge during sputtering can be suppressed, and consequently cracking of the oxide sintered body due to abnormal discharge is suppressed. be able to. Thereby, the cost of forming an oxide semiconductor thin film using a sputtering target can be reduced.
  • an oxide semiconductor thin film having uniform and favorable characteristics can be manufactured. For example, by manufacturing a TFT oxide semiconductor thin film using a sputtering target in a production line for manufacturing a display device, the manufacturing cost of the TFT, and thus the manufacturing cost of the display device, can be suppressed. Furthermore, an oxide semiconductor thin film exhibiting favorable TFT characteristics can be formed, and a high-performance display device can be manufactured.
  • the specific resistance of the oxide sintered body was measured by the four probe method. Specifically, the specific resistance of the oxide sintered body can be measured using a known specific resistance measuring instrument (for example, Lorester GP manufactured by Mitsubishi Chemical Analytech Co., Ltd.). In addition, the specific resistance of this specification points out what was obtained by measuring the distance between each terminal as 1.5 mm. The specific resistance was measured several times (for example, four times) at different locations, and the average value was taken as the specific resistance of the oxide sintered body.
  • a known specific resistance measuring instrument for example, Lorester GP manufactured by Mitsubishi Chemical Analytech Co., Ltd.
  • the specific resistance of this specification points out what was obtained by measuring the distance between each terminal as 1.5 mm. The specific resistance was measured several times (for example, four times) at different locations, and the average value was taken as the specific resistance of the oxide sintered body.
  • FIG. 1 is a schematic cross-sectional view of the sputtering target 1.
  • the sputtering target 1 includes a backing plate 20 and an oxide sintered body 10 fixed on the backing plate 20 with a bonding material 30.
  • the oxide sintered body 10 uses the oxide sintered body according to the embodiment of the present invention. Therefore, when bonding to the backing plate 20 with the bonding material 30, the oxide sintered body is difficult to break and the sputtering target 1 can be manufactured with a high yield.
  • the oxide sintered body of the embodiment of the present invention is obtained by sintering a mixed powder containing zinc oxide, indium oxide, gallium oxide, and tin oxide.
  • the sputtering target of the embodiment of the present invention is obtained by fixing the obtained oxide sintered body on a backing plate. More specifically, the oxide sintered body is manufactured by the following steps (a) to (e). The sputtering target is manufactured by the following steps (f) and (g).
  • the oxide sintered body finally obtained is a mixture containing these oxides so that zinc, indium, gallium and tin are contained in a predetermined ratio.
  • the sintering conditions are controlled so that the crystal phase in the oxide sintered body is formed in an appropriate range.
  • Steps (b) to (d) and (f) to (g) are not particularly limited as long as the oxide sintered body and the sputtering target can be produced, and are usually used in the production of the oxide sintered body and the sputtering target. Can be applied as appropriate.
  • each process is demonstrated in detail, it is not the meaning which limits embodiment of this invention to these processes.
  • Zinc oxide, indium oxide powder, gallium oxide powder and tin oxide powder are mixed in a predetermined ratio, mixed and pulverized.
  • the purity of each raw material powder used is preferably about 99.99% or more. This is because the presence of a small amount of an impurity element may impair the semiconductor characteristics of the oxide semiconductor thin film.
  • Predetermined ratio of each raw material powder means that zinc, indium, gallium and tin with respect to all metal elements (zinc, indium, gallium and tin) excluding oxygen contained in the sintered oxide obtained after sintering. The ratio of the content is within the following range.
  • each raw material powder may be blended so that the ratio is in the above range.
  • a ball mill or bead mill is preferably used for mixing and grinding.
  • the mixed powder can be obtained by charging the raw material powder and water into the mill device and crushing and mixing the raw material powder.
  • a dispersing agent may be added and mixed, and further, a binder may be added and mixed in order to easily form a molded body later.
  • balls and beads (these are referred to as “media”) used in the ball mill and the bead mill, those made of zirconium oxide, nylon or alumina can be used.
  • the pod used for the ball mill and the bead mill a nylon pod, an alumina pod, and a zirconia pod can be used.
  • the mixing time by the ball mill or bead mill is preferably 1 hour or longer, more preferably 10 hours or longer, and further preferably 20 hours or longer.
  • the granulated mixed powder is filled into a mold having a predetermined size and preliminarily molded into a predetermined shape by applying a predetermined pressure (for example, about 49 MPa to about 98 MPa) with a mold press.
  • a predetermined pressure for example, about 49 MPa to about 98 MPa
  • the step (c) may be omitted.
  • An oxide sintered body can be produced.
  • the compact may be placed in a sintering mold and hot pressed.
  • the sintering in step (e) is performed by atmospheric pressure sintering, a dense oxide sintered body can be produced by preforming in step (c).
  • a dispersion material and / or a binder is added to the mixed powder
  • the heating conditions are not particularly limited as long as the temperature and time allow the dispersion material and the binder to be removed.
  • the molded body is held at a heating temperature of about 500 ° C. in the atmosphere for about 5 hours.
  • the step (d) may be omitted.
  • step (c) When step (c) is omitted, that is, when sintering is performed by hot pressing in step (e) and a molded body is not formed, the mixed powder is heated, and the dispersion material in the mixed powder and The binder may be removed (degreasing).
  • the molded body after degreasing is sintered under predetermined sintering conditions to obtain an oxide sintered body.
  • a sintering method both hot press and normal pressure sintering can be used.
  • hot pressing is advantageous in that the sintering temperature can be lowered, and thus the crystal grain size of the obtained oxide sintered body can be reduced.
  • Atmospheric pressure sintering is advantageous in that it does not require pressurization, and therefore requires no pressurization equipment. The sintering conditions and the like will be described below for each of hot press and normal pressure sintering.
  • (I) Hot press In the hot press, the compact is placed in a sintering furnace in a state where it is placed in a sintering mold and sintered in a pressurized state. By sintering the molded body while applying pressure to the molded body, a dense oxide sintered body can be obtained while keeping the sintering temperature relatively low.
  • the hot press uses a sintering mold for pressurizing the compact.
  • the mold for sintering either a metal mold (mold) or a graphite mold (graphite mold) can be used depending on the sintering temperature. In particular, a graphite mold having excellent heat resistance is preferable and can withstand high temperatures of 900 ° C. or higher.
  • the pressure applied to the mold is not particularly limited, but a surface pressure (pressurized pressure) of 10 to 39 MPa is preferable. If the pressure is too high, the sintering graphite mold may be damaged, and a large press facility is required. On the other hand, if it exceeds 39 MPa, the densification promoting effect of the sintered body is saturated, so that there is little profit to pressurize at a higher pressure. On the other hand, if the pressure is less than 10 MPa, densification of the sintered body is difficult to proceed sufficiently. A more preferable pressure condition is 10 to 30 MPa.
  • the sintering temperature is equal to or higher than the temperature at which the mixed powder in the molded body progresses. For example, if the sintering is performed under a surface pressure of 10 to 39 MPa, the sintering temperature is 900 to 1200 ° C. preferable. When the sintering temperature is 900 ° C. or higher, the sintering proceeds sufficiently and the density of the obtained oxide sintered body can be increased.
  • the sintering temperature is more preferably 920 ° C. or higher, and further preferably 940 ° C. or higher. Further, when the sintering temperature is 1200 ° C. or lower, grain growth during sintering is suppressed, and the crystal grain size in the oxide sintered body can be reduced.
  • the sintering temperature is more preferably 1100 ° C. or less, and further preferably 1000 ° C. or less.
  • the time for holding at the predetermined sintering temperature is set to a time during which the sintering of the mixed powder proceeds sufficiently and the density of the obtained oxide sintered body is equal to or higher than the predetermined density.
  • the holding time is preferably 1 to 12 hours.
  • the holding time is 1 hour or longer, the structure in the obtained oxide sintered body can be made uniform.
  • the holding time is more preferably 2 hours or more, and further preferably 3 hours or more. Further, when the holding time is 12 hours or less, grain growth during sintering can be suppressed and the crystal grain size in the oxide sintered body can be reduced.
  • the holding time is more preferably 10 hours or less, and even more preferably 8 hours or less.
  • the average heating rate up to the sintering temperature can affect the size of the crystal grains in the oxide sintered body and the relative density of the oxide sintered body.
  • the average rate of temperature rise is preferably 600 ° C./hr or less, and abnormal growth of crystal grains hardly occurs, so that the ratio of coarse crystal grains can be suppressed.
  • the relative density of the oxide sinter after sintering can be made high that it is 600 degrees C / hr or less.
  • the average temperature rising rate is more preferably 400 ° C./hr or less, and further preferably 300 ° C./hr or less.
  • the lower limit of the average heating rate is not particularly limited, but is preferably 50 ° C./hr or more, more preferably 100 ° C./hr or more from the viewpoint of productivity.
  • the sintering atmosphere is preferably an inert gas atmosphere in order to suppress oxidation and disappearance of the graphite mold for sintering.
  • an atmosphere of an inert gas such as Ar gas and N 2 gas can be applied.
  • the sintering atmosphere can be adjusted by introducing an inert gas into the sintering furnace.
  • the atmospheric gas pressure is preferably atmospheric pressure in order to suppress evaporation of a metal having a high vapor pressure, but may be vacuum (that is, a pressure lower than atmospheric pressure).
  • the sintering temperature is not particularly limited as long as it is equal to or higher than the temperature at which sintering of the mixed powder in the molded body proceeds.
  • the sintering temperature can be 1450 to 1600 ° C.
  • the sintering temperature is more preferably 1500 ° C. or higher, and further preferably 1550 ° C. or higher.
  • the sintering temperature is 1600 ° C. or lower, grain growth during sintering can be suppressed, and the crystal grain size in the oxide sintered body can be reduced.
  • the sintering temperature is more preferably 1580 ° C. or less, and further preferably 1550 ° C. or less.
  • the holding time is not particularly limited as long as the sintering of the mixed powder proceeds sufficiently and the density of the obtained oxide sintered body is equal to or higher than a predetermined density.
  • the holding time may be 1 to 5 hours. it can. When the holding time is 1 hour or longer, the structure in the obtained oxide sintered body can be made uniform.
  • the holding time is more preferably 2 hours or more, and further preferably 3 hours or more. Further, when the holding time is 5 hours or less, grain growth during sintering can be suppressed, and the crystal grain size in the oxide sintered body can be reduced.
  • the holding time is more preferably 4 hours or less, and even more preferably 3 hours or less.
  • the average heating rate is preferably 100 ° C./hr or less, and abnormal growth of crystal grains hardly occurs, so that the ratio of coarse crystal grains can be suppressed. Moreover, the relative density of the oxide sinter after sintering as it is 100 degrees C / hr or less can be made high.
  • the average temperature rising rate is more preferably 90 ° C./hr or less, and still more preferably 80 ° C./hr or less.
  • the lower limit of the average heating rate is not particularly limited, but is preferably 50 ° C./hr or more, more preferably 60 ° C./hr or more from the viewpoint of productivity.
  • the sintering atmosphere is preferably air or an oxygen rich atmosphere.
  • the oxygen concentration in the atmosphere is desirably 50 to 100% by volume.
  • the oxide sintered body can be manufactured by the steps (a) to (e).
  • the obtained oxide sintered body may be processed into a shape suitable for a sputtering target.
  • the processing method of oxide sinter is not specifically limited, What is necessary is just to process to the shape according to various uses by a well-known method.
  • the processed oxide sintered body 10 is bonded onto a backing plate 20 by a bonding material 30.
  • the sputtering target 1 is obtained.
  • the material of the backing plate 20 is not particularly limited, but pure copper or copper alloy having excellent thermal conductivity is preferable.
  • the bonding material 30 various known bonding materials having conductivity can be used, and for example, an In-based solder material and an Sn-based solder material are suitable.
  • the joining method is not particularly limited as long as the backing plate 20 and the oxide sintered body 10 are joined by the bonding material 30 to be used.
  • the oxide sintered body 10 and the backing plate 20 are heated to a temperature (for example, about 140 ° C. to about 220 ° C.) at which the bonding material 30 is melted.
  • a temperature for example, about 140 ° C. to about 220 ° C.
  • the oxide sintered body 10 is applied to the bonding surface 23. Place.
  • the bonding material 30 is solidified and the oxide sintered body 10 is fixed on the bonding surface 23.
  • Example 1 Hot press> (Production of oxide sintered body) 99.99% pure zinc oxide powder (ZnO) 99.99% pure indium oxide powder (In 2 O 3 ), 99.99% pure gallium oxide powder (Ga 2 O 3 ), 99.99% pure Tin oxide powder (SnO 2 ) was blended in the atomic ratio (atomic%) shown in Table 1 to obtain a raw material powder. Water and a dispersant (ammonium polycarboxylate) were added and mixed and pulverized with a ball mill for 20 hours. In this example, a ball mill using a nylon pod and zirconia balls as media was used. Next, the mixed powder obtained in the above step was dried and granulated.
  • ZnO zinc oxide powder
  • In 2 O 3 indium oxide powder
  • Ga 2 O 3 gallium oxide powder
  • Tin oxide powder SnO 2
  • the obtained mixed powder was pressed at a pressure of 1.0 ton / cm 2 using a mold press to prepare a disk-shaped molded body having a diameter of 110 mm and a thickness of 13 mm.
  • the molded body was heated to 500 ° C. under normal pressure and atmospheric atmosphere, and held at that temperature for 5 hours for degreasing.
  • the degreased compact was set in a graphite mold and hot pressed under the conditions shown in Table 2. At this time, N 2 gas was introduced into the furnace and sintered in an N 2 atmosphere.
  • the relative density of the oxide sintered body was determined using the porosity measured as follows. The oxide sintered body is cut in the thickness direction at an arbitrary position, and the cut surface
  • the content (volume ratio) of each crystal phase (Zn 2 SnO 4 , InGaZnO 4 , InGaZn 2 O 5 , InGaZn 3 O 6 and In 2 O 3 ) is calculated from the measured value I of the intensity of the selected peak by the following calculation formula. Asked. In the calculation formula, the ratio of the intensity of the main peak of the target crystal phase to the total intensity (I sum ) of the main peaks of the six crystal phases can be obtained. In the present specification, the strength ratio of the target crystal phase is defined as the content (%) of the crystal phase.
  • I sum I [Zn 2 SnO 4 ] ⁇ 4.
  • the “average crystal grain size ( ⁇ m)” of the oxide sintered body was measured as follows. First, it cut
  • Example 2 Normal pressure sintering>
  • Raw material powders a to c shown in Table 1 were prepared in the same manner as in Example 1.
  • the obtained mixed powder was pressed at a pressure of 1.0 ton / cm 2 using a mold press to prepare a disk-shaped molded body having a diameter of 110 mm and a thickness of 13 mm.
  • the molded body was heated to 500 ° C. under normal pressure and atmospheric atmosphere, and held at that temperature for 5 hours for degreasing.
  • the degreased compact was set in a graphite mold and subjected to normal pressure sintering under the conditions shown in Table 5.
  • N 2 gas was introduced into the furnace and sintered in an N 2 atmosphere.
  • the obtained oxide sintered body was measured for the relative density, the crystal phase content, the average crystal grain size, and the cracks during bonding in the same manner as in Example 1. The measurement results are shown in Tables 6 and 7.
  • Example 5 to 8 having a relative density within the range defined in the embodiment of the present invention, no crack was generated when the oxide sintered body was bonded to the backing plate. Since the density of Comparative Example 1 was as low as 91%, cracking occurred when the oxide sintered body was bonded to the backing plate.
  • Aspect 1 When the content ratio (atomic%) of zinc, indium, gallium and tin with respect to all metal elements excluding oxygen is [Zn] [In], [Ga] and [Sn], respectively. 40 atomic% ⁇ [Zn] ⁇ 55 atomic%, 20 atomic% ⁇ [In] ⁇ 40 atomic%, 5 atomic% ⁇ [Ga] ⁇ 15 atomic%, and 5 atomic% ⁇ [Sn] ⁇ 20 atomic% Satisfied, The relative density is 95% or more, An oxide sintered body containing 5 to 20% by volume of InGaZn 2 O 5 as a crystal phase.
  • Aspect 2 The oxide sintered body according to aspect 1, wherein the maximum equivalent circle diameter of pores in the oxide sintered body is 3 ⁇ m or less.
  • Aspect 3 Oxide sintering according to embodiment 1 or 2, wherein a relative ratio of an average equivalent circle diameter ( ⁇ m) to a maximum equivalent circle diameter ( ⁇ m) of pores in the oxide sintered body is 0.3 or more and 1.0 or less. body.
  • Aspect 4 [Zn] / [In] is more than 1.75 and less than 2.25, The oxide sintered body according to any one of embodiments 1 to 3, further containing 30 to 90% by volume of Zn 2 SnO 4 and 1 to 20% by volume of InGaZnO 4 as a crystal phase.
  • Aspect 5 [Zn] / [In] is less than 1.5, The oxide sintered body according to any one of embodiments 1 to 3, further containing 30 to 90% by volume of In 2 O 3 as a crystal phase.
  • Aspect 6 The oxide sintered body according to any one of embodiments 1 to 3, further containing InGaZn 3 O 6 in a crystal phase in an amount of more than 0% by volume and 10% by volume or less.
  • Aspect 7 7. The oxide sintered body according to any one of embodiments 1 to 6, wherein the crystal grain size is 20 ⁇ m or less.
  • Aspect 8 The oxide sintered body according to aspect 7, wherein the crystal grain size is 5 ⁇ or less.
  • Aspect 9 The oxide sintered body according to any one of embodiments 1 to 8, wherein the specific resistance is 1 ⁇ ⁇ cm or less.
  • Aspect 10 A sputtering target comprising the oxide sintered body according to any one of embodiments 1 to 9 fixed on a backing plate by a bonding material.
  • Aspect 11 A method for producing an oxide sintered body according to any one of aspects 1 to 9, comprising: Preparing a mixed powder containing zinc oxide, indium oxide, gallium oxide and tin oxide in a predetermined ratio; And a step of sintering the mixed powder into a predetermined shape.
  • Aspect 12 The production method according to aspect 11, wherein the sintering step includes holding the mixed powder at a sintering temperature of 900 to 1100 ° C.
  • Aspect 13 The manufacturing method according to aspect 12, wherein, in the sintering step, an average rate of temperature rise to the sintering temperature is 600 ° C./hr or less.
  • Aspect 14 Furthermore, after the step of preparing the mixed powder, before the step of sintering, the step of preforming the mixed powder, 12.
  • Aspect 15 The manufacturing method according to aspect 14, wherein, in the sintering step, an average rate of temperature rise to the sintering temperature is 100 ° C./hr or less.
  • Aspect 16 The oxide sintered body according to any one of aspects 1 to 9 or the oxide sintered body produced by the manufacturing method according to any one of aspects 11 to 15 is bonded to a backing plate with a bonding material.

Abstract

La présente invention concerne un corps fritté d'oxyde qui satisfait l'équation suivante: 40 % en pourcentage atomique ≤ [Zn] ≤ 55 % en pourcentage atomique, 20 % en pourcentage atomique ≤ [In] ≤ 40 % en pourcentage atomique, 5 % en pourcentage atomique ≤ [Ga] ≤ 15 % en pourcentage atomique, et 5 % en pourcentage atomique ≤ [Sn] ≤ 20 % en pourcentage atomique lorsque les pourcentages (% atomique) de teneurs en zinc, indium, gallium et étain par rapport à tous les éléments métalliques à l'exclusion de l'oxygène sont, respectivement, [Zn], [In], [Ga] et [Sn]; et présente une densité relative de 95 % ou plus; et comprend, en tant que phase cristalline, 5 à 20 % en volume de InGaZn 2 O 5 .
PCT/JP2017/004821 2016-04-19 2017-02-09 Corps fritté d'oxyde, cible de pulvérisation et leurs procédés de fabrication WO2017183263A1 (fr)

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CN201780023775.2A CN109071361B (zh) 2016-04-19 2017-02-09 氧化物烧结体和溅射靶、及其制造方法
KR1020187029670A KR102091554B1 (ko) 2016-04-19 2017-02-09 산화물 소결체 및 스퍼터링 타깃, 그리고 그들의 제조 방법
US16/092,400 US20190177230A1 (en) 2016-04-19 2017-02-09 Oxide sintered body and sputtering target, and methods for manufacturing same

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013108181A (ja) * 2008-05-22 2013-06-06 Idemitsu Kosan Co Ltd スパッタリングターゲット、それを用いたアモルファス酸化物薄膜の形成方法、及び薄膜トランジスタの製造方法
WO2013179676A1 (fr) * 2012-05-31 2013-12-05 出光興産株式会社 Cible de pulvérisation
JP2014058415A (ja) * 2012-09-14 2014-04-03 Kobelco Kaken:Kk 酸化物焼結体およびスパッタリングターゲット、並びにその製造方法
JP2014058416A (ja) * 2012-09-14 2014-04-03 Kobelco Kaken:Kk 酸化物焼結体およびスパッタリングターゲット

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013108181A (ja) * 2008-05-22 2013-06-06 Idemitsu Kosan Co Ltd スパッタリングターゲット、それを用いたアモルファス酸化物薄膜の形成方法、及び薄膜トランジスタの製造方法
WO2013179676A1 (fr) * 2012-05-31 2013-12-05 出光興産株式会社 Cible de pulvérisation
JP2014058415A (ja) * 2012-09-14 2014-04-03 Kobelco Kaken:Kk 酸化物焼結体およびスパッタリングターゲット、並びにその製造方法
JP2014058416A (ja) * 2012-09-14 2014-04-03 Kobelco Kaken:Kk 酸化物焼結体およびスパッタリングターゲット

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