JP2023124649A - Sputtering target member and method for producing sputtering target member - Google Patents

Abstract

To provide a sputtering target member having improved thermal shock resistance.SOLUTION: A sputtering target member includes In, Sn, Zn, and O. Measured by X-ray diffraction analysis, the peak intensities of Zn2SnO4 phase, Zn4In2O7 phase, In2O3 phase, and ZnO phase are defined as I(Zn2SnO4), I(Zn4In2O7), I(In2O3), and I(ZnO), where the following relational expressions (1)-(4) hold: I(Zn2SnO4)/(I(Zn2SnO4)+I(Zn4In2O7)+I(In2O3)+I(ZnO))×100≥3.0 (1), I(Zn4In2O7)/I(Zn2SnO4)×100≥1.0 (2), I(In2O3)/I(Zn2SnO4)×100≥1.0 (3), and I(ZnO)/I(Zn2SnO4)×100≤1.0 (4).SELECTED DRAWING: Figure 1

Description

The present invention relates to a sputtering target member and a method for manufacturing a sputtering target member. More particularly, the present invention relates to a sputtering target member that has high thermal shock resistance and is less likely to crack during sputtering or bonding, and a method for manufacturing such a sputtering target member.

In various display devices such as liquid crystal display devices (LCD), electroluminescence display devices (EL), and field emission displays (FED), thin film transistors ( TFT) are widely used.

A sputtering target member for forming an oxide semiconductor thin film such as IGZO (Indium Gallium Zinc Oxide) is known as an active layer material for this type of thin film transistor.

ITZO (Indium Tin Zinc Oxide) has a higher mobility than IGZO, which is an existing oxide semiconductor material, and is expected to be an alternative material to IGZO.

For example, Patent Document 1 (International Publication No. 2010/067571) contains In, Zn and Sn, the density of the sintered body is 90% or more in relative density, the average crystal grain size is 10 μm or less, and the bulk A composite oxide sintered body is disclosed which has a resistance of 30 mΩ·cm or less and a number of aggregated tin oxide particles having a diameter of 10 μm or more of 2.5 or less per 1.00 mm ² . An amorphous oxide film obtained by using a sputtering target member made of this composite oxide sintered body has good uniformity of TFT characteristics, good reproducibility of TFT characteristics, and good yield of TFTs.

In addition, in Patent Document 2 (International Publication No. 2007/037191), indium, tin, and zinc are the main components, and the atomic ratio represented by In / (In + Sn + Zn) is 0.10 to 0.35, Sn / The atomic ratio represented by (In+Sn+Zn) is 0.15 to 0.35, the atomic ratio represented by Zn/(In+Sn+Zn) is 0.50 to 0.70, and In ₂ O ₃ (ZnO) _m (m is an integer of 3 to 9) and a spinel structure compound represented by Zn ₂ SnO ₄ and a sintered oxide sputtering target. This sputtering target has a low indium content, but high density and low resistance.

Further, in Patent Document 3 (Japanese Patent Application Laid-Open No. 2014-218737), Sn: 7 at% or more and In: 0.1% to 35.0 at% are contained with respect to the total amount of metal components, and the balance is An oxide sintered body composed of Zn and inevitable impurities and having a composition in which the atomic ratio Sn/(Sn+Zn) of Sn to Zn is 0.5 or less, wherein the oxide sintered body contains Zn in which In is dissolved. An oxide sputtering target is disclosed which is characterized by having a structure with ₂ SnO ₄ as the main phase. Sputtering using this sputtering target does not contain a sulfur component, so the effect on the reflectance of the laminated reflective layer can be suppressed, the storage stability is high, and the Sn-In-Zn- An O quaternary oxide film can be formed.

In addition, Patent Document 4 (Japanese Patent Application Laid-Open No. 2017-193477) contains 50 to 500 ppm of zirconium, and the ratio of the content of zinc, indium, gallium, and tin to all metal elements excluding oxygen (atomic %). are respectively [Zn], [In], [Ga] and [Sn], 35 atomic % ≤ [Zn] ≤ 55 atomic %, 20 atomic % ≤ ([In] + [Ga]) ≤ 55 atoms %, 5 atomic %≦[Sn]≦25 atomic %. According to this patent document, an oxide sputtering target made of zinc, indium, gallium, and tin has a problem that it is likely to crack due to impact or thermal stress during sputtering or bonding to a backing plate. can be solved by containing zirconium in a specific range.

In addition, Patent Document 5 (Japanese Patent Application Laid-Open No. 2018-59185) describes an oxide sintered body containing 25 atomic% to 33 atomic% of Sn with respect to the entire metal component, and the balance being Zn and unavoidable impurities. and less than 1.0 ZnO phases per 10000 μm ² having a maximum length of 13.0 μm or greater. When the ZnO phase in the structure exists in a coarsened state, the temperature rise of the sputtering target member accompanying high-power sputtering causes a significant difference in thermal expansion between the ZnO phase and the surrounding Zn ₂ SnO ₄ phase. , the thermal load due to the internal stress lowers the fracture resistance. For this reason, the elimination of coarse ZnO phases suppresses the occurrence of cracks even when sputtering is performed at high power.

WO2010/067571 WO2007/037191 JP 2014-218737 A JP 2017-193477 A JP 2018-59185 A

Thus, sputtering target members containing indium, zinc, and tin have the problem that cracks are likely to occur due to thermal shock during sputtering or bonding.

If a crack occurs during sputtering, it becomes a starting point for arcing, and there is concern that many particles will be generated during sputtering film formation. In addition, if cracking occurs during bonding, it causes a decrease in yield. Therefore, there is a demand for an ITZO sputtering target member that has high thermal shock resistance and is less likely to crack during sputtering or bonding.

The present invention was completed in view of the above problems, and in one embodiment, it is an object of the present invention to provide a sputtering target member with improved thermal shock resistance. Another object of the present invention is to provide a method for manufacturing such a sputtering target member.

As a result of intensive studies by the present inventors, the ITZO sputtering target member has a composition that contains a specific phase and does not contain a ZnO phase, thereby improving thermal shock resistance and causing cracks during sputtering and bonding. I found that it becomes difficult. The present invention has been completed based on the above findings, and is exemplified below.

[1]
The peak intensities of _{the Zn2SnO4 phase, the Zn4In2O7 phase , the In2O3} phase, and the ZnO phase, which contain In, Sn, Zn, and O _and are measured by X-ray diffraction analysis, are represented by _I ( Zn ₂ SnO ₄ ), I(Zn ₄ In ₂ O ₇ ), I(In ₂ O ₃ ), and I(ZnO), a sputtering target member satisfying the following relational expressions (1) to (4).
I(Zn ₂ SnO ₄ )/(I(Zn ₂ SnO ₄ )+I(Zn ₄ In ₂ O ₇ )+I(In ₂ O ₃ )+I(ZnO))×100≧3.0 (1)
I(Zn ₄ In ₂ O ₇ )/I(Zn ₂ SnO ₄ )×100≧1.0 (2)
I(In ₂ O ₃ )/I(Zn ₂ SnO ₄ )×100≧1.0 (3)
I(ZnO)/I( _Zn2SnO4 ) x 100≤1.0 ( ₄ )
[2]
The peak intensity ratio I( _Zn4In2O7 )/I( _Zn2SnO4 ) _{× 100} of _{the Zn4In2O7} phase _{to the Zn2SnO4 phase} by X-ray diffraction analysis is 3.0 or more, and The sputtering target member according to [ _{1 ]} , wherein the peak _intensity ratio I( _In2O3 )/I( _Zn2SnO4 )×100 _of the _In2O3 phase to the Zn2SnO4 phase is 3.0 _or more.
[3]
The peak intensity ratio I( _Zn4In2O7 )/I( _Zn2SnO4 ) _{× 100} of the _Zn4In2O7 phase _{to the Zn2SnO4 phase} by X-ray diffraction analysis is 7.0 or more, _{and [1]} or _{[ 2} ], wherein the peak intensity ratio I( _In2O3 )/I( _Zn2SnO4 )×100 of _{the In2O3} phase to _the Zn2SnO4 phase is 7.0 or more. Sputtering target member.
[4]
The atomic ratio represented by In/(In+Sn+Zn) is 20 at% to 30 at%, the atomic ratio represented by Sn/(In+Sn+Zn) is 5 at% to 23.3 at%, and the atomic ratio represented by Zn/(In+Sn+Zn) is The sputtering target member according to any one of [1] to [3], wherein the atomic ratio of 51.7 at % to 75 at %.
[5]
The sputtering target member according to any one of [1] to [4], having an average crystal grain size of 1.0 μm to 3.0 μm.
[6]
The sputtering target member according to any one of [1] to [5], which has a relative density of 96.5% or more.
[7]
The sputtering target member according to any one of [1] to [6], which has a bulk resistivity of 1.0 mΩ·cm to 50 mΩ·cm.
[8]
The sputtering target member according to any one of [1] to [6], which has a bulk resistivity of 1.0 mΩ·cm to 1.5 mΩ·cm.
[9]
The sputtering target member according to any one of [1] to [6], which has a bulk resistivity of 5.0 mΩ·cm to 50 mΩ·cm.
[10]
A method for manufacturing a sputtering target member, comprising:
a calcining step of mixing indium oxide powder, tin oxide powder and zinc oxide powder and calcining to form a calcined product;
A method of manufacturing a sputtering target member, comprising: pulverizing the calcined material to obtain a calcined powder containing In, Sn, Zn, and O; and a sintering step of sintering the calcined powder by a hot press method. .
[11]
As for the relationship between the amounts of the indium oxide powder, the tin oxide powder, and the zinc oxide powder, the atomic ratio represented by In/(In+Sn+Zn) is 20 at % to 30 at %, and the atoms represented by Sn/(In+Sn+Zn). The method for producing a sputtering target member according to [10], wherein the ratio is 5 at % to 23.3 at %, and the atomic ratio represented by Zn/(In+Sn+Zn) is 51.7 at % to 75 at %.
[12]
The method for producing a sputtering target member according to [10] or [11], wherein the calcination step is performed at 500° C. to 1300° C. for 1 hour to 100 hours.
[13]
The sintering step is performed by a hot press method under conditions of a sintering temperature of 900° C. to 1200° C., a surface pressure of 150 kgf/cm ² to 400 kgf/cm ² , and a holding time of 1 hour to 5 hours. 12].
[14]
A method for manufacturing a sputtering target member, comprising:
a step of mixing and pulverizing indium oxide powder, tin oxide powder, zinc oxide powder, and coarse particles containing an In ₂ O ₃ phase and having a median diameter (D50) of 10 μm to 100 μm to obtain a mixed powder slurry;
A step of granulating the mixed powder slurry using a spray dryer to obtain a granulated powder;
a step of molding the granulated powder to obtain a molded body;
A method for producing a sputtering target member, comprising the step of sintering the molded body by a normal pressure sintering method under conditions of a sintering temperature of 1200° C. to 1500° C. and a holding time of 5 hours to 50 hours.
[15]
A method for manufacturing a sputtering target member, comprising:
a step of mixing and pulverizing indium oxide powder, tin oxide powder, zinc oxide powder, and coarse particles containing an In ₂ O ₃ phase and having a median diameter (D50) of 10 μm to 100 μm to obtain a mixed powder slurry;
a step of drying the mixed powder slurry to obtain a dry powder;
A method for producing a sputtering target member, comprising a sintering step of sintering the dry powder by a hot press method.
[16]
Regarding the relationship between the amounts of the indium oxide powder, the tin oxide powder, the zinc oxide powder, and the coarse particles, the atomic ratio represented by In/(In+Sn+Zn) is 20 at % to 30 at %, and Sn/(In+Sn+Zn). The atomic ratio represented by is 5 at% to 23.3 at%, and the atomic ratio represented by Zn / (In + Sn + Zn) is 51.7 at% to 75 at%. Sputtering according to [14] or [15] A method of manufacturing a target member.
[17]
[ ¹⁵ ] or ^[ 16].

According to one embodiment of the present invention, a sputtering target member with improved thermal shock resistance can be provided. The present invention, according to another embodiment, can provide a method of manufacturing such a sputtering target member.

4 is a graph showing the X-ray diffraction analysis results of Example 1 of the present invention. 4 is a graph showing the X-ray diffraction analysis results of Example 3 of the present invention. 4 is a graph showing the X-ray diffraction analysis results of Comparative Example 1 of the present invention.

Next, embodiments of the present invention will be described in detail. It is understood that the present invention is not limited to the following embodiments, and that design changes, improvements, etc., can be made as appropriate based on the ordinary knowledge of those skilled in the art without departing from the scope of the present invention. should.

In one embodiment _of the present invention _{, the sputtering} target member comprises In, Sn, Zn, and O, with _Zn2SnO4 phase, _Zn4In2O7 phase, _In2O3 as determined by X-ray diffraction analysis. When the peak intensities _of the phase and the ZnO phase are respectively I( _Zn2SnO4 ), I( _Zn4In2O7 ), _I ( _In2O3 ), and I( _ZnO ), the _following (1) satisfying _the relational expression ( ₄ ): I( _Zn2SnO4 )/(I( _{Zn2SnO4 )} +I( _Zn4In2O7 )+I( _In2O3 )+I( _ZnO ))× ₁₀₀ ≧ _3.0 (1) _; I(Zn4In2O7 ₎ /I(Zn2SnO4 _{) *} 100≧1.0( ₂ ) _; I( _In2O3 )/I(Zn2SnO4 ₎ * 100≧1.0(3 ₎ ; I(ZnO)/I( _Zn2SnO4 )×100≦1.0(4). Such a crystal structure can be obtained by using a calcined powder containing In, Sn, Zn and O and hot pressing (H/P) under predetermined conditions, or by using an In ₂ O ₃ phase, as described later. It can be obtained by a method using coarse particles.

(1. Composition)
In one embodiment of the present invention, the sputtering target member comprises Indium (In), Tin (Sn), Zinc (Zn) and Oxygen (O). Typically, it is mainly composed of indium tin oxide (ITZO) made from inorganic compounds of indium oxide ( _In2O3 ), tin oxide ( _SnO2 ) and zinc _oxide (ZnO).

The sputtering target member of one embodiment of the present invention has an atomic ratio represented by In/(In+Sn+Zn) of 20 at% to 30 at%, and an atomic ratio represented by Sn/(In+Sn+Zn) of 5 at% to 23.3 at. %, and the atomic ratio represented by Zn/(In+Sn+Zn) is 51.7 at % to 75 at %. As a result, a crystal structure, which will be described later, can be suitably formed, and the thermal shock resistance of the sputtering target member can be improved.

If the atomic ratio represented by In/(In+Sn+Zn) is less than 20 at %, the resulting film may have low mobility and may not satisfy properties required for an oxide semiconductor. On the other hand, when the atomic ratio represented by In/(In+Sn+Zn) exceeds 30 at %, the carrier concentration is high when formed into a film, which may not satisfy the characteristics required for an oxide semiconductor. Further, when the atomic ratio represented by Sn/(In+Sn+Zn) is less than 5 at %, the carrier concentration is high when formed into a film, which may not satisfy the properties required for an oxide semiconductor. On the other hand, when the atomic ratio represented by Sn/(In+Sn+Zn) exceeds 23.3 at %, the amount of Zn ₂ SnO ₄ phases increases, which may reduce the thermal shock resistance. Further, when the atomic ratio represented by Zn/(In+Sn+Zn) is less than 51.7 at %, the carrier concentration is high when formed into a film, which may not satisfy the properties required for an oxide semiconductor. On the other hand, if the atomic ratio represented by Zn/(In+Sn+Zn) exceeds 75 at %, the resulting film may have low mobility and may not satisfy characteristics required for an oxide semiconductor.

From the above viewpoints, the sputtering target member of one embodiment of the present invention has an atomic ratio represented by In / (In + Sn + Zn) of 20 at% to 30 at %, and an atomic ratio represented by Sn / (In + Sn + Zn) is 10 at. % to 20 at %, and the atomic ratio represented by Zn/(In+Sn+Zn) is more preferably 55 at % to 60 at %.

(2. X-ray diffraction analysis)
In one embodiment of the sputtering target member of the present invention, the crystal phases identified by X-ray diffraction analysis are Zn ₂ SnO ₄ phase, Zn ₄ In ₂ O ₇ phase, and In ₂ O ₃ phase and no ZnO phase. Preferably, _the sputtering target member contains _{a Zn2SnO4} phase and a _Zn4In2O7 phase as main phases, contains _{an In2O3} phase, and does not contain a ZnO phase _. By adopting such a crystal structure, the thermal shock resistance of the sputtering target member can be improved, and the occurrence of arcing during sputtering due to cracking of the sputtering target member and a decrease in yield during bonding can be suppressed. . The peak intensity ratio of the Zn ₂ SnO ₄ phase to the sum of all peak intensities is I(Zn ₂ SnO ₄ )/(I(Zn ₂ SnO ₄ )+I(Zn ₄ In ₂ O ₇ )+I(In ₂ O ₃ )+I A Zn ₂ SnO ₄ phase is assumed to exist when (ZnO))×100 is 3.0 or more.

In a preferred embodiment of the present invention, _{the peak} intensity ratio of the _Zn4In2O7 phase to _{the Zn2SnO4} phase by X-ray diffraction analysis _, I( _Zn4In2O7 )/ _I ( _Zn2SnO4 ) x 100, _is It is 1.0 or more, more preferably 3.0 or more, even more preferably 7.0 or more, still more preferably 20.0 or more, and even more preferably 30.0 or more. As a result, the presence of the Zn ₄ In ₂ O ₇ phase having high thermal shock resistance improves the thermal shock resistance of the target. The peak intensity ratio of the Zn ₄ In ₂ O ₇ phase to the Zn ₂ SnO ₄ phase by X-ray diffraction analysis I(Zn ₄ In ₂ O ₇ )/I(Zn ₂ SnO ₄ )×100 has no particular upper limit, but is typically Typically, it is 3,000 or less, for example, 1,500 or less.

In another preferred embodiment of _the present invention, the _peak intensity ratio I( _In2O3 )/I( _Zn2SnO4 )×100 of the _In2O3 phase to _{the Zn2SnO4} phase by X-ray diffraction _analysis is 1. It is 0 or more, more preferably 3.0 or more, and even more preferably 7.0 or more. As a result, the presence of the In ₂ O ₃ phase having high thermal shock resistance improves the thermal shock resistance of the target. The peak intensity ratio of the In ₂ O ₃ phase to the Zn ₂ SnO ₄ phase by X-ray diffraction analysis I(In ₂ O ₃ )/I(Zn ₂ SnO ₄ )×100 does not particularly have an upper limit, but is typically 1,000. or less, for example 500 or less, for example 300 or less.

In another preferred embodiment of the present invention, the peak intensity ratio _I (ZnO)/I( _Zn2SnO4 )× ₁₀₀ of the ZnO phase to the _Zn2SnO4 phase by X-ray diffraction analysis is 1.0 or less. In the present invention, the crystal phase identified by X-ray diffraction analysis does not contain the ZnO phase, but due to the peak of the (107) plane of Zn ₄ In ₂ O ₇ , a peak is observed at the position of the (101) plane of the ZnO phase. may be Even in that case, the thermal _shock resistance is improved by setting the peak intensity ratio I(ZnO)/I( _Zn2SnO4 )× ₁₀₀ of the ZnO phase to the _Zn2SnO4 phase by X-ray diffraction analysis to 1.0 or less. do. In other words, if _{the peak intensity ratio I(ZnO)/I(Zn2SnO4 )} × ₁₀₀ of the ZnO phase to the _Zn2SnO4 phase by X-ray diffraction analysis is 1.0 or less, it is considered not to contain the ZnO phase. be able to. A preferred range of _the peak intensity ratio I(ZnO)/I( _Zn2SnO4 )× ₁₀₀ of the ZnO phase to the _Zn2SnO4 phase by X-ray diffraction analysis is typically 0.1 or less, for example 0.1. 01 or less.

The peak intensity can be derived using a fully automatic multi-purpose X-ray diffractometer (model: Ultima) manufactured by Rigaku Corporation equipped with a Cu (copper) tube. Specifically, first, a part of the sputtering target member is sampled and powdered, and the powder under the sieve is sieved with a mesh size of 100 μm to obtain a sample. A powder X-ray diffraction method is then used on this sample to obtain its X-ray diffraction profile. After subjecting the obtained X-ray diffraction profile to data processing such as Kα2 removal, the crystal phase is identified using the PDF (Powder Diffraction File) of ICDD (International Center for Diffraction Data). In addition, for the calculation of the peak intensity, for each crystal phase, for the peak with the highest intensity in the 2θ range in Table 1 below, the integrated intensity is calculated by peak height (cps) × half width (degree), peak intensity I (**) ("**" means the chemical formula corresponding to the peak). Here, the measurement conditions are a tube voltage of 40 kV, a tube current of 30 mA, a scan speed of 18°/min, and a step of 0.02°. Since the actual peak may undergo a peak shift due to distortion or the like, the ICDD card is referred to and the maximum peak around ±0.2° is adopted as the peak.

(3. Average grain size)
In one embodiment of the present invention, the sputtering target member preferably has an average grain size of 1.0 μm to 3.0 μm. By setting the average crystal grain size to 3.0 μm or less, the strength of the sputtering target member is increased, and the occurrence of cracks due to thermal shock can be suppressed. From this point of view, the average crystal grain size of the sputtering target member is more preferably 2.7 μm or less. In addition, from the viewpoint of ease of realization and the effect of improving performance, the lower limit of the average crystal grain size can be set to 1.0 μm or more, for example, 1.3 μm or more.

In order to measure the average crystal grain size, samples are taken from a total of five locations near the center and four corners of the sputtering target member. Then, for each sample, a 2000x SEM image was taken at an arbitrary point of the cross section of the target, five straight lines were drawn on the taken image, and the length of the line segment formed by each straight line intersecting with the crystal grain was coded. Then, the average value of the cord lengths is obtained and taken as the average crystal grain size.

(4. Relative density)
In one embodiment of the present invention, the relative density of the sputtering target member is preferably 96.5% or higher. By setting the relative density to 96.5% or more, the strength of the sputtering target member is increased, and the occurrence of cracks during sputtering can be suppressed. From this point of view, the relative density of the sputtering target member is more preferably 97.0% or more, even more preferably 97.5% or more, even more preferably 98.0% or more, It is even more preferably 98.5% or more, and even more preferably 99.0% or more.

The relative density can be calculated by the formula: relative density=measured relative density÷reference relative density×100(%). Here, the reference relative density is a relative density value calculated from the theoretical relative density of oxides of elements other than oxygen among the constituent elements of the sintered body. For example, in the case of a target containing In, Sn, Zn, and O, indium oxide ( _In2 O ₃ ), tin oxide (SnO ₂ ), and zinc oxide (ZnO) are used to calculate the theoretical relative density. Further, from the elemental analysis values (at% or mass%) of indium, tin, and zinc in the sintered body, the mass ratio of indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), and zinc oxide (ZnO) was calculated. calculate. Then, for each of indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), and zinc oxide (ZnO), sum the values obtained by multiplying the mass ratio by the relative density, divide by 100 g/cm ³ , and obtain the standard Find the relative density. On the other hand, the measured relative density is a value obtained by dividing weight by volume. In the case of a sintered body, the volume is calculated by the Archimedes method.

(5. Bulk resistivity)
In one embodiment of the invention, the bulk resistivity of the sputtering target member is preferably between 1.0 mΩ·cm and 50 mΩ·cm. Occurrence of arcing can be suppressed by setting the resistance to 50 mΩ·cm or less. From this point of view, the bulk resistivity of the sputtering target member is more preferably 20 mΩ·cm or less. In addition, from the viewpoint of ease of realization and the effect of improving performance, the lower limit of the bulk resistivity can be set to 1.0 mΩ·cm or more. The bulk resistivity varies depending on the sintering method, and is generally 1.0 mΩ·cm to 1.0 mΩ·cm to 1 in the case of the hot pressing method described later or the hot pressing method using coarse grains containing an In ₂ O ₃ phase as raw material powder. It is preferably 5.0 mΩ·cm to 50 mΩ·cm in the case of pressureless sintering using coarse particles containing an In ₂ O ₃ phase, which will be described later, as raw material powder. Moreover, in the case of the pressureless sintering method using coarse grains containing an In ₂ O ₃ phase as raw material powder, the bulk resistivity of the sputtering target member is more preferably 20 mΩ·cm or less.

The bulk resistivity is obtained by measuring three points in the center and the periphery of the surface of the sputtering target member subjected to sputtering using the four-probe method, and taking the average value thereof.

(6. Manufacturing method)
(6-1. Method of hot pressing calcined powder)
In one embodiment of the method for producing a sputtering target member of the present invention, the sputtering target member as described above is formed into a calcined product by mixing indium oxide powder, tin oxide powder and zinc oxide powder, and calcining the mixture. a calcining step, pulverizing the calcined product to obtain a calcined powder containing In, Sn, Zn, and O, and sintering the calcined powder by a hot press method at a temperature of 900 ° C. to 1200 ° C., It can be manufactured by successively performing sintering steps under conditions of a surface pressure of 150 kgf/cm ² to 400 kgf/cm ² and a holding time of 1 hour to 5 hours.

In the above embodiment, first, indium oxide powder, tin oxide powder, and zinc oxide powder are prepared, and these powders are mixed to obtain raw material powder. The raw material powder has an atomic ratio represented by In/(In+Sn+Zn) of 20 at% to 30 at%, an atomic ratio represented by Sn/(In+Sn+Zn) of 5 at% to 23.3 at%, and Zn/(In+Sn+Zn ) can be adjusted to 51.7 at % to 75 at %.

For example, indium oxide powder has a bulk density of 0.3 g/cm ³ to 0.8 g/cm ³ , a median diameter (D50) of 0.5 μm to 2.5 μm, and a specific surface area of 3.0 m ² /g to 6.0 μm. 0 m ² /g is used, and the tin oxide powder has a bulk density of 0.2 g/cm ³ to 0.6 g/cm ³ , a median diameter (D50) of 1.0 μm to 2.5 μm, and a specific surface area of 3. The zinc oxide powder has ^{a bulk density of 0.3 g/cm 3 to} 0.6 g/cm ³ and a median diameter (D50 ⁾ of 0.3 μm to 0.3 μm. 2.0 μm, specific surface area: 2.0 m ² /g to 6.0 ^{m 2} /g can be used. These are mixed to obtain a particle size distribution suitable for close packing. In this specification, the median diameter (D50) means the median diameter (D50) in the volume-based cumulative particle size distribution measured by the laser diffraction/scattering method in accordance with JISZ8825:2013.

Next, after obtaining a mixture of indium oxide powder, tin oxide powder and zinc oxide powder, the mixture is calcined to form a calcined product. In this calcination step, heat treatment is preferably performed at 500° C. to 1300° C. for 1 hour to 100 hours. Forming this calcined product in advance facilitates obtaining the desired crystal phase.

Next, this calcined material is pulverized to obtain a calcined powder containing In, Sn, Zn, and O. The pulverization of the calcined product can be performed by using a ball mill, roll mill, pearl mill, jet mill, or the like, and the degree of pulverization can be appropriately set.

Next, the calcined powder is sintered by a hot press method under the conditions of a sintering temperature of 900° C. to 1200° C., a surface pressure of 150 kgf/cm ² to 400 kgf/cm ² and a holding time of 1 hour to 5 hours. The hot press atmosphere is preferably an inert gas atmosphere such as Ar.

If the sintering temperature is lower than 900°C, the sintering may not proceed sufficiently, resulting in a low density. On the other hand, if the sintering temperature exceeds 1200° C., the density may decrease due to reduction of In ₂ O ₃ , SnO ₂ and ZnO.

To reach the sintering temperature, it is preferable to raise the temperature at a rate of 30° C./hour to 600° C./hour, more preferably 60° C./hour to 400° C./hour. If the heating rate is less than 30° C./hour, excessive energy and time may be expended, resulting in increased costs and decreased productivity. On the other hand, if the heating rate exceeds 600° C./hour, cracks may occur due to the rapid temperature rise, and pores may remain inside, resulting in a decrease in density.

Further, the temperature drop rate after the holding time is over is preferably 30° C./hour to 600° C./hour, more preferably 100° C./hour to 400° C./hour. If the cooling rate is slower than 30° C./hour, it may take too long and the productivity may drop. On the other hand, if the temperature drop rate exceeds 600° C./hour, cracks may occur due to the rapid temperature drop, and pores may remain inside, resulting in a decrease in density.

The temperature rise rate and temperature drop rate are measured using a thermocouple installed in the sintering furnace, and the average value of each rate obtained by dividing the temperature difference from the most recent measured value by the time interval can be obtained. can.

If the surface pressure is less than 150 kgf/cm ² , a molded article with sufficient strength and density cannot be obtained. On the other hand, if the surface pressure exceeds 400 kgf/cm ² , the molded body itself may be destroyed due to deformation due to the release of the pressure when the molded body is removed from the mold, which may be undesirable in terms of production. be.

If the holding time at the above sintering temperature is shorter than 1 hour, the sintering does not proceed sufficiently, and there is a concern that the sputtering target member may have a lower density or warp. On the other hand, if the holding time exceeds 5 hours, excessive energy and time may be expended, resulting in increased costs and reduced productivity.

The temperature drop rate described above can be realized by using a manufacturing method, air cooling by blowing circulation gas, water cooling using a cooling tower, or the like.

A sputtering target member can be obtained by cutting the sintered body obtained by the above method into a predetermined size and shape and grinding it by a known method such as mechanical grinding or chemical grinding. Such a sputtering target member is generally subjected to sputtering with a base material bonded to its surface.

(6-2. Atmospheric sintering method or hot press method using coarse grains containing _{In 2} O ₃ phase as raw material powder)
In another embodiment of the method for producing a sputtering target member of the present invention, coarse grains containing an In ₂ O ₃ phase can also be used. First, indium oxide powder, tin oxide powder, zinc oxide powder, and coarse particles containing an In ₂ O ₃ phase are prepared. The raw material powder has an atomic ratio represented by In/(In+Sn+Zn) of 20 at% to 30 at%, an atomic ratio represented by Sn/(In+Sn+Zn) of 5 at% to 23.3 at%, and Zn/(In+Sn+Zn ) can be adjusted to 51.7 at % to 75 at %.

For example, indium oxide powder has a bulk density of 0.3 g/cm ³ to 0.8 g/cm ³ , a median diameter (D50) of 0.5 μm to 2.5 μm, and a specific surface area of 3.0 m ² /g to 6.0 μm. 0 m ² /g is used, and the tin oxide powder has a bulk density of 0.2 g/cm ³ to 0.6 g/cm ³ , a median diameter (D50) of 1.0 μm to 2.5 μm, and a specific surface area of 3. The zinc oxide powder has ^{a bulk density of 0.3 g/cm 3 to} 0.6 g/cm ³ and a median diameter (D50 ⁾ of 0.3 μm to 0.3 μm. 2.0 μm, specific surface area: 2.0 m ² /g to 6.0 m ² /g, coarse particles containing an In ₂ O ₃ phase having a median diameter (D50) of 10 μm to 100 μm can be used.

The median diameter (D50) of the coarse grains containing the In ₂ O ₃ phase is preferably in the range of 10 μm to 100 μm. If the median diameter (D50) exceeds 100 μm, sintering may be hindered and the density may decrease. If it is less than 10 μm, the In ₂ O ₃ phase may disappear due to reaction with other raw material powders . From this point of view, the median diameter (D50) of the coarse particles containing the In ₂ O ₃ phase is more preferably 20 μm or more and 80 μm or less, or more preferably 40 μm or more and 60 μm or less.

Also, the coarse grains containing the In ₂ O ₃ phase may or may not contain Zn, Sn, for example, ITO (In ₂ O ₃ : 90% by weight, SnO ₂ : 10% by weight) sintered It can be a coarse particle obtained by pulverizing the body.

Next, the indium oxide powder, tin oxide powder, and zinc oxide powder are mixed and pulverized. Mixing and pulverization can be carried out, for example, by dispersing the above powders in water to form a mixed powder slurry, followed by wet mixing and fine pulverization with a bead mill. The median diameter (D50) of the mixed powder after pulverization is preferably 0.1 μm to 0.5 μm.

Next, coarse particles containing an In ₂ O ₃ phase are mixed into the mixed powder slurry. After mixing, wet mixing and fine pulverization can also be performed with a bead mill. At this time, an aqueous solution containing 4% to 10% by mass of PVA (polyvinyl alcohol) acting as a binder can be added in an amount of 50cc/kg to 250cc/kg to the raw material powder. In addition, a mixed powder slurry is prepared by dispersing indium oxide powder, tin oxide powder, zinc oxide powder, and coarse particles containing the In ₂ O ₃ phase in water without mixing the coarse particles containing the In ₂ O ₃ phase separately. , can also be mixed and pulverized.

Next, the mixed powder slurry is granulated with a spray dryer to obtain granulated powder. As a result, the fluidity of the raw material powder can be improved, and the filling condition during press molding can be improved.

Next, the granulated powder is molded to obtain a molded body. The granulated powder is filled into a mold, and a pressure of 400 kgf/cm ² to 1000 kgf/cm ² is maintained for 1 to 3 minutes to mold into a predetermined shape. If the pressure is less than 400 kgf/cm ² , a molded article with sufficient strength and density cannot be obtained ^. It may be destroyed due to deformation due to being released from, which may be undesirable in terms of production. Also, the obtained compact can be vacuum-packaged and further densified by CIP (cold isostatic pressing). CIP can be performed, for example, under the condition that a pressure of 1000 kgf/cm ² to 2500 kgf/cm ² is maintained for 1 minute to 3 minutes.

Next, the compact is sintered by a normal pressure sintering method under the conditions of a sintering temperature of 1200° C. to 1500° C. and a holding time of 5 hours to 50 hours. The atmosphere for normal pressure sintering is preferably an atmosphere containing an oxidizing gas such as oxygen or air.

If the sintering temperature is lower than 1200° C., the sintering may not proceed sufficiently, resulting in a low density. On the other hand, if the sintering temperature exceeds 1500° C., the density may decrease due to reduction of In ₂ O ₃ , SnO ₂ and ZnO.

To reach the above sintering temperature, it is preferable to raise the temperature at a rate of 30° C./hour to 600° C./hour, more preferably 60° C./hour to 300° C./hour. If the heating rate is less than 30° C./hour, excessive energy and time may be expended, resulting in increased costs and decreased productivity. On the other hand, if the heating rate exceeds 600° C./hour, cracks may occur due to the rapid temperature rise, and pores may remain inside, resulting in a decrease in density.

Also, the temperature drop rate after the holding time is preferably 30° C./hour to 1000° C./hour, more preferably 100° C./hour to 600° C./hour. If the temperature drop rate is less than 30° C./hour, excessive energy and time are spent, which can lead to increased costs and decreased productivity. On the other hand, if the temperature drop rate exceeds 1000° C./hour, cracks may occur due to the rapid temperature drop, and pores may remain inside, resulting in a decrease in density.

The temperature rise rate and temperature drop rate are measured using a thermocouple installed in the sintering furnace, and the average value of each rate obtained by dividing the temperature difference from the most recent measured value by the time interval can be obtained. can. Moreover, the above-described temperature drop rate can be realized by using a manufacturing method, air cooling by blowing circulation gas, water cooling using a cooling tower, or the like.

If the holding time at the above sintering temperature is shorter than 5 hours, the sintering will not proceed sufficiently, and there is concern that the sputtering target member will have a lower density and warp. On the other hand, if the holding time exceeds 50 hours, excessive energy and time may be expended, resulting in increased costs and decreased productivity.

Further, instead of molding the granulated powder into a compact and sintering the compact at normal pressure, the mixed powder slurry is dried to obtain a dry powder, and the dry powder is sintered at normal pressure or hot under the above conditions. You can also press. Although the drying method is not particularly limited, a constant temperature dryer, a vibration dryer, or the like can be used.

In each of the above embodiments, a hot press method can be used instead of the pressureless sintering method. The conditions of the hot pressing method can be a sintering temperature of 900° C. to 1200° C., a surface pressure of 150 kgf/cm ² to 400 kgf/cm ² and a holding time of 1 hour to 5 hours. The detailed conditions of the hot pressing method can be the same as those of the above embodiment using the calcined powder, so please refer to the above description. If the raw material powder according to this embodiment is used, the same crystal structure can be obtained even if the hot pressing method is used, so the thermal shock resistance of the sputtering target member can be improved.

A sputtering target member can be obtained by cutting the sintered body obtained by any of the above methods into a predetermined size and shape and grinding it by a known method such as mechanical grinding or chemical grinding. Such a sputtering target member is generally subjected to sputtering with a base material bonded to its surface.

As raw materials, indium oxide powder, zinc oxide powder, and tin oxide powder each having a median diameter (D50) of 1 μm were weighed so as to have the atomic ratio shown in Table 2 to prepare a mixed powder.

Next, for Examples 1 to 5 and Comparative Example 2, the mixed powder was calcined under the conditions of 1300 ° C. for 5 hours, and then the obtained calcined material was pulverized with a bead mill until the particle size became 1.2 μm, Next, it was sintered by hot pressing under the conditions shown in Table 2. In Table 2, "H/P" means hot press method and "normal pressure" means normal pressure sintering method. The holding time at the sintering temperature was 2-3 hours.

In Example 6, coarse grains prepared by pulverizing an ITO sintered body (In ₂ O ₃ : 90% by mass, SnO ₂ : 10% by mass) were used as the raw material, and raw material powder was used without forming a calcined product. Mixed. The median diameter (D50) of coarse particles was 51 μm. The coarse particles and the above-mentioned indium oxide powder, zinc oxide powder, and tin oxide powder are dispersed in water to form a mixed powder slurry, which is wet-mixed and finely pulverized by a bead mill, dried and granulated using a spray dryer, A granulated powder was obtained. The median diameter (D50) of the granulated powder was 47 μm. This granulated powder was molded under conditions of a surface pressure of 400 kgf/cm ² and held for 1 minute, followed by CIP under conditions of a pressure of 1795 kgf/cm ² and held for 1 minute. Pressureless sintering was carried out under atmospheric conditions.

In Comparative Examples 1 and 3, no calcined product was formed and no coarse particles containing an In ₂ O ₃ phase were used. After mixing the above-described indium oxide powder, zinc oxide powder, and tin oxide powder, A sintering process was performed. For Comparative Example 3, sintering was performed at normal pressure.

For the sintered bodies of these Examples and Comparative Examples, the peak intensity, average crystal grain size, relative density, and bulk resistivity by X-ray diffraction analysis were calculated by the method described above. Table 2 shows the results. 1 to 3 show the X-ray diffraction analysis spectra of Examples 1 and 3 and Comparative Example 1. FIG.

(Thermal shock test)
The sintered bodies of Examples and Comparative Examples were subjected to a thermal shock test in accordance with JIS R 1648:2002 (Method of Thermal Shock Test for Fine Ceramics). First, a sample piece (over 36 mm in length, 4.0 mm in width, and 3.0 mm in thickness) was cut out from a sputtering target member with a diamond cutter. Then, the sample piece was heated by a hot plate at a heating rate of 5° C./min and held at a temperature of 200° C. for 30 minutes. After that, the sample piece was dropped from a height of 30 cm from the water surface into water of room temperature (23±2° C.) and a depth of 30 cm to give a thermal shock. For the sample piece subjected to this thermal shock test and the sample piece not subjected to the thermal shock test, resistance was measured according to the three-point bending strength measurement method of JIS R 1601: 2008 (test method for bending strength of fine ceramics). Folding strength was measured. Using the obtained average bending strength (P ₂ ) of the sample piece subjected to the thermal shock test and the average bending strength (P ₁ ) of the sample piece not subjected to the thermal shock test, (P ₁ - P ₂ )/P ₁ ×100 [%] was defined as the rate of decrease in strength before and after thermal shock. A material having a low rate of decrease in strength before and after thermal shock has high thermal shock resistance. Table 2 shows the results.

(Discussion)
In Examples 1 to 5, which were produced according to the conditions of the present invention, they contained Zn ₂ SnO ₄ phase, Zn ₄ In ₂ O ₇ phase, and In ₂ O ₃ phase as crystal phases, and did not contain ZnO phase. I found out. Also, the decrease in bending strength before and after the thermal shock test was not significant. In Example 6, the calcined product _was not formed, and the sintering step was performed _under normal _pressure after mixing the raw material powders. _Three phases remain, resulting in Zn ₂ SnO ₄ phase, Zn ₄ In ₂ O ₇ phase, and In ₂ O ₃ phase, but no ZnO phase, equivalent performance to Examples 1-5. was gotten.

On the other hand, in Comparative Examples 1 to 3, since they were not produced according to the conditions of the present invention, the crystal structure did not satisfy the requirements of the present invention, and the bending strength before and after sputtering was remarkably lowered.

Claims (17)

The peak intensities of _{the Zn2SnO4 phase, the Zn4In2O7 phase , the In2O3} phase, and the ZnO phase, which contain In, Sn, Zn, and O _and are measured by X-ray diffraction analysis, are represented by _I ( Zn ₂ SnO ₄ ), I(Zn ₄ In ₂ O ₇ ), I(In ₂ O ₃ ), and I(ZnO), a sputtering target member satisfying the following relational expressions (1) to (4).
I(Zn ₂ SnO ₄ )/(I(Zn ₂ SnO ₄ )+I(Zn ₄ In ₂ O ₇ )+I(In ₂ O ₃ )+I(ZnO))×100≧3.0 (1)
I(Zn ₄ In ₂ O ₇ )/I(Zn ₂ SnO ₄ )×100≧1.0 (2)
I(In ₂ O ₃ )/I(Zn ₂ SnO ₄ )×100≧1.0 (3)
I(ZnO)/I( _Zn2SnO4 ) x 100≤1.0 ( ₄ ) The peak intensity ratio I( _Zn4In2O7 )/I( _Zn2SnO4 ) _{× 100} of _{the Zn4In2O7} phase _{to the Zn2SnO4 phase} by X-ray diffraction analysis is 3.0 or more, and The sputtering target member according to claim 1, wherein the peak _intensity ratio I( _In2O3 )/I( _Zn2SnO4 ) x _{100 of} the _In2O3 phase to the _Zn2SnO4 phase is 3.0 _or more. The peak intensity ratio I( _Zn4In2O7 )/I( _Zn2SnO4 ) _{× 100} of the _Zn4In2O7 phase _{to the Zn2SnO4 phase} by X-ray diffraction analysis is 7.0 or more, _and The sputtering target according to _{claim 1 or 2 ,} wherein the peak intensity ratio I( _In2O3 )/I( _Zn2SnO4 )×100 _of the _In2O3 phase to the Zn2SnO4 phase is 7.0 or more. Element. The atomic ratio represented by In/(In+Sn+Zn) is 20 at% to 30 at%, the atomic ratio represented by Sn/(In+Sn+Zn) is 5 at% to 23.3 at%, and the atomic ratio represented by Zn/(In+Sn+Zn) is The sputtering target member according to any one of claims 1 to 3, wherein the atomic ratio of 51.7at% to 75at%. The sputtering target member according to any one of claims 1 to 4, having an average crystal grain size of 1.0 µm to 3.0 µm. The sputtering target member according to any one of claims 1 to 5, having a relative density of 96.5% or more. The sputtering target member according to any one of claims 1 to 6, which has a bulk resistivity of 1.0 mΩ·cm to 50 mΩ·cm. The sputtering target member according to any one of claims 1 to 6, which has a bulk resistivity of 1.0 mΩ·cm to 1.5 mΩ·cm. The sputtering target member according to any one of claims 1 to 6, which has a bulk resistivity of 5.0 mΩ·cm to 50 mΩ·cm. A method for manufacturing a sputtering target member, comprising:
a calcining step of mixing indium oxide powder, tin oxide powder and zinc oxide powder and calcining to form a calcined product;
A method of manufacturing a sputtering target member, comprising: pulverizing the calcined material to obtain a calcined powder containing In, Sn, Zn, and O; and a sintering step of sintering the calcined powder by a hot press method. . As for the relationship between the amounts of the indium oxide powder, the tin oxide powder, and the zinc oxide powder, the atomic ratio represented by In/(In+Sn+Zn) is 20 at % to 30 at %, and the atoms represented by Sn/(In+Sn+Zn). 11. The method for manufacturing a sputtering target member according to claim 10, wherein the ratio is 5 at % to 23.3 at %, and the atomic ratio represented by Zn/(In+Sn+Zn) is 51.7 at % to 75 at %. 12. The method of manufacturing a sputtering target member according to claim 10, wherein the calcination step is performed at 500° C. to 1300° C. for 1 hour to 100 hours. 10. Claims 10 and 12, wherein the sintering step is performed by a hot press method under conditions of a sintering temperature of 900°C to 1200°C, a surface pressure of 150 kgf/cm ² to 400 kgf/cm ² , and a holding time of 1 hour to 5 hours. A method for producing a sputtering target member according to any one of the above. A method for manufacturing a sputtering target member, comprising:
a step of mixing and pulverizing indium oxide powder, tin oxide powder, zinc oxide powder, and coarse particles containing an In ₂ O ₃ phase and having a median diameter (D50) of 10 μm to 100 μm to obtain a mixed powder slurry;
A step of granulating the mixed powder slurry using a spray dryer to obtain a granulated powder;
a step of molding the granulated powder to obtain a molded body;
A method for producing a sputtering target member, comprising the step of sintering the molded body by a normal pressure sintering method under conditions of a sintering temperature of 1200° C. to 1500° C. and a holding time of 5 hours to 50 hours. A method for manufacturing a sputtering target member, comprising:
a step of mixing and pulverizing indium oxide powder, tin oxide powder, zinc oxide powder, and coarse particles containing an In ₂ O ₃ phase and having a median diameter (D50) of 10 μm to 100 μm to obtain a mixed powder slurry;
a step of drying the mixed powder slurry to obtain a dry powder;
A method for producing a sputtering target member, comprising a sintering step of sintering the dry powder by a hot press method. Regarding the relationship between the amounts of the indium oxide powder, the tin oxide powder, the zinc oxide powder, and the coarse particles, the atomic ratio represented by In/(In+Sn+Zn) is 20 at % to 30 at %, and Sn/(In+Sn+Zn). The atomic ratio represented by is 5 at% to 23.3 at%, and the atomic ratio represented by Zn / (In + Sn + Zn) is 51.7 at% to 75 at%, The sputtering target member according to claim 14 or 15. manufacturing method. Claim 15 or 16, wherein the sintering step is performed by a hot press method under conditions of a sintering temperature of 900°C to 1200°C, a surface pressure of 150 kgf/cm ² to 400 kgf/cm ² , and a holding time of 1 hour to 5 hours. 2. A method for manufacturing the sputtering target member according to 1.