JP7203064B2 - sputtering target - Google Patents

Description

The present disclosure relates to a suitable sputtering target for forming a metal film or nitride film with good piezoelectric response in a piezoelectric element.

In modern and future society, the working population is expected to decrease as the birth rate declines and the population ages, so automation using the Internet of Things (IoT) is also being pursued in the manufacturing industry. In addition, the automobile industry is also transitioning to a society in which AI and the like are the main players in the production of automobiles that can operate automatically without human operation.

Wireless ultra-high-speed communication is an important technology for automation and autonomous driving, and high-frequency filters are indispensable for ultra-high-speed wireless communication. Also, in order to increase the speed of wireless communication, the frequency band used in the conventional fourth generation mobile communication (4G) has been changed from the 3.4 GHz band to the frequency 3.7 GHz used in the fifth generation mobile communication (5G). It is planned to shift to the high frequency side to 5 GHz and 28 GHz bands. When this transition is made, high frequency filtering also becomes technically difficult with conventional Surface Acoustic Wave (SAW) filters. Therefore, technology is changing from surface acoustic wave filters to bulk acoustic wave (BAW) filters.

Aluminum nitride films are mainly used as piezoelectric films for BAW filters and piezoelectric element sensors. Aluminum nitride is used as a piezoelectric film because it is known to have a high amplitude enhancement factor called Q value (Quality factor). However, since it cannot be used at high temperatures, a nitride film containing aluminum and rare earth elements is promising in order to increase the temperature and Q value of the piezoelectric element.

As a sputtering target for forming a nitride film containing an aluminum element and a rare earth element, a sputtering target made of an alloy of Al and Sc and containing 25 atomic % to 50 atomic % of Sc, wherein the oxygen content is There is a disclosure of a sputtering target having a Vickers hardness (Hv) variation of 20% or less, with a content of 2000 ppm by mass or less (see Patent Document 1, for example). It is stated that this sputtering target is manufactured through a melting process and then plastic working such as a forging process (see, for example, Patent Document 1). In addition, Patent Document 1 describes that the variation in the Sc content between the TOP (top surface of the target) and the BTM (bottom surface of the target) of the sputtering target was within the range of ±2 atomic% (paragraph 0040 of the specification). -0041).

Further, in the method for producing a sputtering target made of an alloy of aluminum and a rare earth element, the element ratio of aluminum to the rare earth element is within a range that satisfies that the obtained alloy target is composed of only two kinds of intermetallic compounds. A raw material is prepared, an alloy powder of aluminum and a rare earth element is produced from this raw material by an atomizing method, and the obtained alloy powder is sintered into an alloy target in a vacuum atmosphere by a hot press method or a discharge plasma sintering method. There is a technique for producing a body (see Patent Document 2, for example).

_In addition, it is known that the piezoelectric constant d33 of the Sc _x Al _1-x N alloy changes drastically due to the compositional deviation of the Sc concentration (for example, see Non-Patent Document 1 and FIG. 3).

WO2017/213185 JP 2015-96647 A

Kazuhiko Kano et al., Denso Technical Review Vol. 17, 2012, p202-207

In the production of aluminum alloys, while the melting point of aluminum is as low as 660°C, the melting points of elements added to aluminum are 1541°C for scandium, 1522°C for yttrium, 1668°C for titanium, and 1668°C for zirconium. is 1855° C., and hafnium is 2233° C., which is a very high temperature, and the melting point difference between aluminum and the added element is 800° C. or more.

Therefore, as in Patent Document 1, if the amount of scandium added to aluminum is increased, there are compositions with a melting point of 1400 ° C. or higher, and differences in growth of intermetallic compounds occur due to temperature unevenness during solidification after melting. Therefore, it is difficult to produce a sputtering target having a uniform composition in the in-plane direction and the thickness direction of the sputtering target.

In addition, if the sputtering target is composed only of an intermetallic compound by using a melting method as in Patent Document 1, the sputtering target becomes very hard and brittle. Cracks are likely to occur in the target.

In addition, when it is produced by a dissolution method as in Patent Document 1, the precipitation phase grows large, and composition unevenness occurs in the in-plane direction and thickness direction of the sputtering target. The composition distribution of the alloy thin film becomes unstable.

Patent Document 1 describes that the variation in the Sc content between the TOP and BTM of the sputtering target was within a range of ±2 atomic %. It is also necessary to suppress variations not only in the thickness direction but also in the in-plane direction.

In particular, as pointed out in FIG. 3 of Non-Patent Document 1, it is important to maintain a uniform composition in the in-plane direction and the thickness direction because the compositional deviation may cause extreme changes in the characteristics. .

In order to solve the problem when it is produced by the melting method, it is necessary to eliminate the compositional deviation between aluminum and rare earth at the time of powder as in Patent Document 2, and to close the final shape of the product when sintering. It is conceivable to reduce plastic working by finishing in shape. However, if impurities such as chlorine, fluorine, and oxygen are mixed in too much, the chlorine, fluorine, and oxygen in the sputtering target will be released by heating during film formation, and abnormal discharge will easily occur, resulting in poor orientation of the resulting film. Otherwise, the properties of the film may be deteriorated, or particles may be generated to reduce the yield of the film.

Therefore, the object of the present disclosure is to provide a sputtering target that suppresses the contamination of the impurity chlorine element in the sputtering target, and suppresses the occurrence of abnormal discharge due to chlorine when a thin film is formed using the sputtering target, and the orientation To provide a sputtering target capable of forming a thin film having excellent properties.

As a result of intensive studies by the present inventors in order to solve the above problems, the present inventors found that the problem of chlorine element contamination can be suppressed by reducing the concentration of elemental chlorine, which is an impurity, in the sputtering target to a predetermined level or less. completed. That is, the sputtering target according to the present invention is a sputtering target containing aluminum and further containing one or both of a rare earth element and a titanium group element, wherein the chlorine content is 100 ppm or less, and the rare earth element The element is at least one of scandium and yttrium, the titanium group element is at least one of zirconium and hafnium, and the sputtering target is selected from the rare earth elements and the titanium group elements. It is characterized by containing 10 to 75 atomic % of at least one element . When a thin film is formed using a sputtering target, the occurrence of abnormal discharge due to chlorine can be suppressed, and a thin film with better orientation can be formed. In addition, by suppressing the occurrence of abnormal discharge due to chlorine, it is possible to form a thin film with good yield while suppressing the generation of particles.

The sputtering target according to the present invention preferably has a fluorine content of 100 ppm or less. When a thin film is formed using a sputtering target, the occurrence of abnormal discharge due to fluorine can be suppressed, and a thin film with better orientation can be formed. In addition, by suppressing the occurrence of abnormal discharge due to fluorine, it is possible to form a thin film with good yield while suppressing the generation of particles.

The sputtering target according to the present invention preferably has an oxygen content of 500 ppm or less. When a thin film is formed using the sputtering target, the occurrence of abnormal discharge due to oxygen can be suppressed, and a thin film with better orientation can be formed. In addition, by suppressing the occurrence of abnormal discharge due to oxygen, it is possible to form a thin film with good yield while suppressing the generation of particles.

In the sputtering target according to the present invention, an intermetallic compound composed of at least two elements selected from aluminum, rare earth elements and titanium group elements is preferably present in the sputtering target. Variation in composition can be suppressed by reducing the number of portions containing aluminum as an element, a rare earth element as an element, or a titanium group element as an element. When an intermetallic compound is present in the target, the difference in sputtering rate between metal elements is reduced, and the uneven composition of the obtained film is reduced.

In the sputtering target according to the present invention, one, two, three or four types of intermetallic compounds may be present in the sputtering target. Variation in composition can be suppressed by reducing the number of portions containing aluminum as an element, a rare earth element as an element, or a titanium group element as an element. The presence of one or more types of intermetallic compounds further reduces the difference in sputtering rate between the metal elements, and the compositional unevenness of the obtained film is further reduced.

In the sputtering target according to the present invention, one or more nitrides of at least one element selected from aluminum, rare earth elements and titanium group elements may be present in the sputtering target. When the nitride film of the piezoelectric element is formed, it is possible to cope with an increase in temperature of the piezoelectric element and to increase the Q value.

The sputtering target according to the present invention includes at least one of a material containing aluminum and a rare earth element, a material containing aluminum and a titanium group element, and a material containing aluminum, a rare earth element and a titanium group element in an aluminum matrix. Either having a structure in which species are present, or at least a phase containing only rare earth elements and inevitable impurities as metal species and a phase containing only titanium group elements and inevitable impurities as metal species in the aluminum matrix phase It is preferable to have a tissue composed of multiple phases containing one or both. It is possible to provide a sputtering target with improved electrical conductivity, which improves productivity when forming a film using, for example, a DC sputtering apparatus.

The sputtering target of the present disclosure suppresses the contamination of chlorine elements, which are impurities, in the sputtering target, suppresses the occurrence of abnormal discharge due to chlorine when a thin film is formed using the sputtering target, and has good orientation. A thin film can be formed. In addition, by suppressing the occurrence of abnormal discharge due to chlorine, it is possible to form a thin film with good yield while suppressing the generation of particles.

FIG. 3 is a schematic diagram showing measurement points for composition analysis in the in-plane direction of sputtering of a disk-shaped target. FIG. 3 is a schematic diagram showing measurement points for composition analysis in the target thickness direction of a disk-shaped target shown in the BB cross section. FIG. 3 is a schematic diagram showing measurement points for composition analysis in the in-plane direction of sputtering of a square plate-shaped target. It is a schematic diagram showing the measurement points of the composition analysis in the target thickness direction of the square plate-shaped target shown in the CC cross section. FIG. 2 is a conceptual diagram for explaining measurement points for composition analysis of a cylindrical target. It is an explanatory view for explaining a concept of an aluminum matrix. 4 is an image of the surface of the Al—Sc target in Example 1 observed with an electron microscope. 4 is an image of the surface of the Al—Sc target in Comparative Example 4 observed with an electron microscope. 4 is an image of the surface of the Al—ScN target in Example 4 observed with a microscope.

Hereinafter, the present invention will be described in detail by showing embodiments, but the present invention is not interpreted as being limited to these descriptions. Various modifications may be made to the embodiments as long as the effects of the present invention are achieved.

The sputtering target according to the present embodiment contains aluminum and further contains either one or both of a rare earth element and a titanium group element, and has a chlorine content of 100 ppm or less and 50 ppm or less. is preferred, and 30 ppm or less is more preferred. If the chlorine content exceeds 100 ppm, the chlorine in the sputtering target is released by heating during film formation, causing abnormal discharge without stabilizing the voltage applied to the sputtering target, resulting in particle generation. In addition, the chlorine content in the sputtering target must be 100 ppm or less because it causes a decrease in the yield of the formed thin film and the formation of a thin film with poor orientation.

In the sputtering target according to the present embodiment, the fluorine content is preferably 100 ppm or less, more preferably 50 ppm or less, and even more preferably 30 ppm or less. If the fluorine content exceeds 100 ppm, the fluorine in the sputtering target is released by heating during film formation, and the voltage applied to the sputtering target is not stabilized, causing abnormal discharge and particle generation. It is preferable to adjust the fluorine content in the sputtering target to 100 ppm or less.

In the sputtering target according to the present embodiment, the oxygen content is preferably 500 ppm or less, more preferably 300 ppm or less, and even more preferably 100 ppm or less. If the oxygen content exceeds 500 ppm, the oxygen in the sputtering target is released by heating during film formation, and the voltage applied to the sputtering target is not stabilized, causing abnormal discharge and particle generation. It is preferable to adjust the oxygen content in the sputtering target to 500 ppm or less because it causes a decrease in the yield of the formed thin film and the formation of a thin film with poor orientation.

In the sputtering target according to the present embodiment, the carbon content is preferably 200 ppm or less, more preferably 100 ppm or less, and even more preferably 50 ppm or less. If the carbon content exceeds 200 ppm, carbon is taken into the film during sputtering, resulting in the formation of a thin film with deteriorated crystallinity. In addition, if a strong compound is formed on the target surface, the conductivity is impaired and particles are generated due to abnormal discharge, which reduces the yield of the film. Therefore, it is preferable to adjust the carbon content in the sputtering target to 200 ppm or less.

In the sputtering target according to the present embodiment, the silicon content is preferably 200 ppm or less, more preferably 100 ppm or less, and even more preferably 50 ppm or less. If the silicon content exceeds 200 ppm, oxides and nitrides of silicon are formed during sputtering, and abnormal discharge is caused from these as starting points, particles are generated, and the yield of the formed thin film is reduced. It is preferable to adjust the content of silicon therein to 200 ppm or less.

In the sputtering target according to the present embodiment, the composition of the sputtering target in the sputtering in-plane direction and the target thickness direction in (Condition 1) or (Condition 2) has a difference of ± 3% with respect to the reference composition. within ±2%, preferably ±1% or less. Here, the reference composition is the average value of the total 18 compositions measured according to (Condition 1) or (Condition 2). If the difference exceeds ±3% from the standard composition, the sputtering rate may differ when the sputtering target is formed. Also, even if the substrate is the same, the piezoelectric characteristics may differ due to different compositions depending on the location of the piezoelectric film. Therefore, in order to suppress the deterioration of the yield of the piezoelectric element, it is preferable to control the difference in the composition of the sputtering target in the sputtering plane direction and the target thickness direction within ±3% with respect to the reference composition. If it has a uniform composition in the in-plane direction and the thickness direction, it is possible to suppress a decrease in yield due to changes in characteristics such as piezoelectric response due to compositional deviation when forming a thin film used for a piezoelectric element or the like. .

(Condition 1)
Sputtering in-plane direction: The sputtering target is a disk-shaped target with a center O and a radius r, and the composition analysis measurement point is on a virtual cross line orthogonal to the center O as an intersection point, and is 1 of the center O. A total of 9 locations: 4 locations 0.45r away from the center O and 4 locations 0.9r away from the center O.
Target thickness direction: A cross section passing through any one of the virtual crosshairs is formed, and the cross section is a rectangle with length t (that is, the thickness of the target is t) and width 2r, and composition analysis The measurement points are the center X on the vertical transverse line passing through the center O and a total of three points 0.45 t apart from the center X (referred to as point a, point X, and point b), from point a on the cross section A total of 2 locations 0.9r apart from the left and right sides, a total of 2 locations 0.9r apart from the point X toward the left and right sides, and 0.9r from the point b toward the left and right sides A total of 9 measurement points, including 2 separate points, are used as measurement points.
(Condition 2)
Sputtering in-plane direction: the sputtering target is a rectangle having a vertical length of L1 and a horizontal length of L2 (including a square where L1 and L2 are equal; alternatively, the rectangle has a length of J, A cylinder side developed rectangle of perimeter K is included, in which L2 corresponds to length J, L1 corresponds to perimeter K, and J>K for length J and perimeter K. , J=K or J<K), and the measurement point of the composition analysis is a virtual cross line that intersects the center of gravity O as an intersection, and the virtual cross line is orthogonal to the sides of the rectangle. Then, one point at the center of gravity O, a total of two points on the virtual crosshairs that are 0.25L1 apart in the vertical direction from the center of gravity O, and a total of two points that are 0.25L2 in the horizontal direction from the center of gravity O. , a total of 2 locations separated from the center of gravity O by a distance of 0.45L1 in the vertical direction, and a total of 2 locations separated from the center of gravity O by a distance of 0.45L2 in the horizontal direction.
Target thickness direction: Of the virtual crosshairs, a cross section passing through a line parallel to either one of the vertical L1 and horizontal L2 sides is formed. The target has a thickness of t) and a rectangle with a width of L2, and the measurement points for composition analysis are a total of three points (a Point, X point, and b point.), a total of two points on the cross section, 0.45L2 away from point a toward the left and right sides, and 0.45L2 away from point X toward the left and right sides. A total of 9 measurement points, ie, 2 points in total and 2 points in total 0.45L2 away from point b toward the left and right sides are used as measurement points.

FIG. 1 is a schematic diagram showing measurement locations for composition analysis in the sputtering in-plane direction of a disk-shaped target (hereinafter also referred to as measurement locations). A measurement point in the sputtering plane direction of the sputtering target will be described. In the case of a disk-shaped target, the radius is preferably 25-225 mm, more preferably 50-200 mm. The thickness of the target is preferably 1-30 mm, more preferably 3-26 mm. In the present embodiment, a greater effect can be expected for large targets.

In FIG. 1, the sputtering target 200 is a disc-shaped target with a center O and a radius r. The measurement points are on a virtual cross line (L) orthogonal to the center O as an intersection point, one point (S1) at the center O, and four points in total (S3, S5, S6 and S8 ), and a total of four locations (S2, S4, S7 and S9) 0.9r away from the center O, totaling nine locations.

FIG. 2 is a schematic diagram showing the measurement points of the composition analysis in the target thickness direction of the disk-shaped target shown in the BB cross section of FIG. Measurement points in the thickness direction of the target will be described.

In FIG. 2, the BB cross section of FIG. 1 is a rectangle with length t (that is, the thickness of the target is t) and width 2r. Then, the measurement points are the center X (C1) on the vertical transverse line passing through the center O and a total of three points (a point (C4), X point (C1), b point (C5 ) on the cross section, a total of two points (C6, C7) 0.9r away from the point a toward the left and right sides, and 0.9r away from the point X toward the left and right sides Two points (C2, C3) in total and two points (C8, C9) separated by 0.9r from the point b toward the left and right sides are taken as nine measurement points in total.

FIG. 3 is a schematic diagram showing the measurement points of the composition analysis in the sputtering plane direction of the square plate-shaped target, and the measurement points of the sputtering target in the sputtering plane direction of (Condition 2) will be described with reference to FIG. do. For a rectangular or square target, the vertical and horizontal lengths are preferably 50-450 mm, more preferably 100-400 mm. The thickness of the target is preferably 1-30 mm, more preferably 3-26 mm. In the present embodiment, a greater effect can be expected for large targets.

The sputtering target 300 is a rectangular target with a vertical length of L1 and a horizontal length of L2 (including squares where L1 and L2 are equal). A form that is L2 is shown. The measurement point is a virtual cross line (Q) that intersects perpendicularly with the center of gravity O as a point of intersection. A total of 2 locations (P6, P8) at a distance of 0.25L1 in the vertical direction from the center of gravity O, a total of 2 locations (P3, P5) at a distance of 0.25L2 in the horizontal direction from the center of gravity O, the center of gravity O A total of 2 locations (P7, P9) at a distance of 0.45L1 in the vertical direction from the center of gravity O, and a total of 2 locations (P2, P4) at a distance of 0.45L2 in the horizontal direction from the center of gravity O, total 9 Let it be a place. Note that when the sputtering target is rectangular, L1 and L2 can be appropriately selected regardless of the length of the sides.

FIG. 4 is a schematic diagram showing the measurement points of the composition analysis in the target thickness direction of the square plate-shaped target shown in the CC cross section of FIG. The measurement points in the thickness direction of the target will be described.

In FIG. 4, section C-C of FIG. 3 forms a section through a line parallel to the horizontal side, the section is a rectangle of length t (i.e., the thickness of the target is t) and width L2, and the measurement The points are the center X on the vertical transverse line passing through the center of gravity O and a total of three points separated by 0.45 t vertically from the center X (referred to as point a (D4), point X (D1), and point b (D5)). On the cross section, a total of two locations (D6, D7) 0.45L2 apart from point a toward the left and right sides, and a total of two locations (D2, D3) and a total of 2 points (D8, D9) separated by 0.45L2 from point b toward the left and right sides are used as measurement points.

(cylindrical sputtering target)
FIG. 5 is a conceptual diagram for explaining measurement points of a cylindrical target. When the sputtering target has a cylindrical shape, the side surface of the cylinder is the sputtering surface, and the developed view is a rectangle or a square. In FIG. 5, when the sputtering target 400 has a cylindrical shape with a height (length) J and a cylinder circumference K, consider an EE cross section and a DD developed plane so that the cross section is at both ends. . First, the measurement points for composition analysis in the target thickness direction are considered in the same manner as in FIG. 4 on the EE cross section. That is, the height J of the cylindrical member corresponds to L2 in FIG. 4, and the thickness of the cylindrical member corresponds to the thickness t in FIG. Also, the measurement points in the in-plane direction of the sputtering plane are considered in the same manner as in FIG. 3 on the DD developed plane. That is, the height J of the cylindrical member corresponds to L2 in FIG. 3, and the circumferential length K of the barrel of the cylindrical member corresponds to L1 in FIG. The relationship J>K, J=K, or J<K is established between the length J and the circumference K. In the case of a cylindrical target, the circumference of the cylinder is preferably 100 to 350 mm, more preferably 150 to 300 mm. The length of the cylinder is preferably 300-3000 mm, more preferably 500-2000 mm. The thickness of the target is preferably 1-30 mm, more preferably 3-26 mm. In the present embodiment, a greater effect can be expected for large targets.

The sputtering target according to the present embodiment includes at least one of a material containing aluminum and a rare earth element, a material containing aluminum and a titanium group element, and a material containing aluminum, a rare earth element and a titanium group element in the aluminum matrix. or at least a phase containing only rare earth elements and inevitable impurities as metal species, a phase containing only titanium group elements and inevitable impurities as metal species, and It is preferable to have a structure composed of a composite phase containing any one of phases containing only rare earth elements, titanium group elements and inevitable impurities as metal species. An object of the present invention is to provide a sputtering target with improved electrical conductivity, which improves productivity in film formation using, for example, a DC sputtering apparatus.

Next, a specific microstructure of the sputtering target will be described for this embodiment. Specific microstructures of the sputtering target are classified into, for example, first to fifth structures and modifications thereof. Here, the form having an aluminum matrix is the second structure, the fifth structure, and their modifications, particularly the second structure and its modification, the second structure-2, and , the fifth organization and the fifth organization-2 which is its modification.

[First organization]
The sputtering target according to the present embodiment includes a material containing aluminum and a rare earth element (hereinafter also referred to as RE), a material containing aluminum and a titanium group element (hereinafter also referred to as TI), and aluminum and a rare earth element and a titanium group element. That is, in the first structure, material A containing Al and RE, material B containing Al and TI, or material C containing Al, RE, and TI exist, and the coexistence of material A and material B, material There are seven combinations of materials in the form of coexistence of material A and material C, coexistence of material B and material C, or coexistence of material A, material B and material C.

In this embodiment, the term "material" means the material that constitutes the sputtering target, and includes, for example, alloys or nitrides. Further, alloys include, for example, solid solutions, eutectics, and intermetallics. In addition, if the nitride is metal-like, it may be included in the alloy.

[Second organization]
The sputtering target according to the present embodiment includes at least one of a material containing aluminum and a rare earth element, a material containing aluminum and a titanium group element, and a material containing aluminum, a rare earth element and a titanium group element in the aluminum matrix. One species has a second tissue present. That is, in the second structure, the seven combinations of materials mentioned in the first structure are present in the aluminum matrix. That is, the second structure includes a form in which material A, material B, or material C exists in the aluminum matrix, and coexistence of material A and material B, material A and material C in the aluminum matrix. There are combinations of forms in which coexistence, coexistence of material B and material C, or coexistence of material A, material B, and material C are observed.

In this embodiment, the term "aluminum matrix" can also be referred to as an aluminum matrix. FIG. 6 illustrates the concept of the aluminum matrix using the second structure as an example. The microstructure of the sputtering target 100 is such that a material containing aluminum and a rare earth element, specifically an Al-RE alloy, exists in the aluminum matrix. That is, the Al matrix 3 connects a plurality of Al--RE alloy particles 1 together. The Al--RE alloy particles 1 are aggregates of crystal grains 2 of Al--RE alloy. The boundaries between the Al--RE alloy grains 2a and the adjacent Al--RE alloy grains 2b are grain boundaries. The Al matrix 3 is an aggregate of aluminum crystal grains 4 . The boundaries between the aluminum crystal grains 4a and the adjacent aluminum crystal grains 4b are grain boundaries. Thus, in the present embodiment, the term "mother phase" means a phase that joins together a plurality of metal particles, alloy particles, or nitride particles, and the joining phase itself is an aggregate of crystal grains. It is a concept. In general, intermetallic compounds or nitrides are characterized by poor electrical conductivity and plastic workability (ductility), which are characteristics of metals. If the Al--RE alloy of the sputtering target consists of only an intermetallic compound, only a nitride, or an intermetallic compound and a nitride, the electrical conductivity of the sputtering target tends to decrease. However, the presence of the aluminum (mother) phase can prevent a decrease in the electrical conductivity of the sputtering target as a whole. Also, if the Al--RE alloy of the sputtering target is composed of intermetallics only, nitrides only, or intermetallics and nitrides, the sputtering targets tend to be very brittle. However, the presence of the aluminum (mother) phase can alleviate the brittleness of the target.

[Third organization]
The sputtering target according to the present embodiment includes a phase containing only aluminum and inevitable impurities as metal species, a phase containing only rare earth elements and inevitable impurities as metal species, and a phase containing only titanium group elements and inevitable impurities as metal species. a third structure composed of a composite phase containing either or both; That is, the third structure includes a form composed of a composite phase containing a phase containing aluminum as a metal species and a phase containing a rare earth element as a metal species, a phase containing aluminum as a metal species and a titanium group as a metal species. A mode composed of a composite phase containing a phase containing an element, or a composite phase containing a phase containing aluminum as a metal species, a phase containing a rare earth element as a metal species, and a phase containing a titanium group element as a metal species There are three combinations of the forms shown.

Inevitable impurities include, for example, Fe and Ni, and the atomic % concentration of the inevitable impurities is preferably 200 ppm or less, more preferably 100 ppm or less.

In the present embodiment, the term "phase" is a solid phase, and is a concept of an aggregate united by the same composition, for example, an aggregate of particles of the same composition.

In this embodiment, the term "composite phase" is a concept that two or more "phases" are present. These phases differ from each other in composition for each type.

[Fourth organization]
The sputtering target according to the present embodiment includes a phase containing aluminum and further containing either or both of a rare earth element and a titanium group element, a phase containing only aluminum and inevitable impurities as a metal species, and a rare earth element as a metal species. and at least one of a phase containing only inevitable impurities and a phase containing only titanium group elements and inevitable impurities as metal species. That is, the fourth structure has the following 21 combinations of phases. Here, a phase containing aluminum and a rare earth element is called phase D, a phase containing aluminum and a titanium group element is called phase E, and a phase containing aluminum, a rare earth element and a titanium group element is called phase F. Phase G is a phase containing only aluminum and inevitable impurities as metal species, phase H is a phase containing only rare earth elements and inevitable impurities as metal species, and phase I is a phase containing only titanium group elements and inevitable impurities as metal species. do. The fourth structure consists of the following composite phases: phase D and phase G, phase D and phase H, phase D and phase I, phase D and phase G and phase H, phase D and phase G and phase I, phase Phase D and Phase H and Phase I, Phase D and Phase G and Phase H and Phase I, Phase E and Phase G, Phase E and Phase H, Phase E and Phase I, Phase E and Phase G and Phase H, Phase E and Phase E Phase G to Phase I, Phase E to Phase H to Phase I, Phase E to Phase G, Phase H to Phase I, Phase F to Phase G, Phase F to Phase H, Phase F to Phase I, Phase F to Phase G and phase H, phase F, phase G and phase I, phase F, phase H and phase I, or phase F, phase G, phase H and phase I.

[Fifth organization]
The sputtering target according to the present embodiment includes at least one or both of a phase containing only rare earth elements and inevitable impurities as metal species and a phase containing only titanium group elements and inevitable impurities as metal species in the aluminum matrix. It has a fifth structure composed of a composite phase containing: The fifth structure is composed of a composite phase in which the following three phases are present in the aluminum matrix. That is, the fifth structure is a composite phase in which phase H exists in the aluminum matrix, a composite phase in which phase I exists in the aluminum matrix, or a phase H and phase I in the aluminum matrix. Composed of composite phases.

Also in this embodiment, the term "aluminum matrix" can also be referred to as an aluminum matrix. In the fifth structure, the microstructure of the sputtering target is such that phase H, phase I, or both phase H and phase I exist in the aluminum matrix to form a composite phase. The aluminum matrix is an aggregate of aluminum crystal grains, and the boundaries between aluminum crystal grains and adjacent aluminum crystal grains are grain boundaries. Phase H is, for example, the concept of aggregates of particles of the same composition. Phase I is similar. When both phase H and phase I are present, two phases with different compositions are present in the aluminum matrix.

[Modified example of the fifth organization]
The sputtering target according to this embodiment includes a form in which the composite phase further includes a phase containing only aluminum and inevitable impurities as metal species in the fifth structure.
The fifth structure is composed of a composite phase in which the following three phases are present in the aluminum matrix. That is, this composite phase is a composite phase in which phase H and phase G exist in an aluminum matrix, a composite phase in which phase I and phase G exist in an aluminum matrix, or a composite phase in which phase H and phase H exist in an aluminum matrix. It is a composite phase in which Phase I and Phase G are present.

Modifications of the first structure to the fifth structure and the fifth structure further include the following forms.

[First Organization-2]
The sputtering target according to this embodiment has a first structure and the material is an alloy, has a first structure and the material is a nitride, or has a first structure , and the material is a combination of an alloy and a nitride. Here, the material refers to a form in which material A containing Al and RE, material B containing Al and TI, or material C containing Al, RE, and TI exists, coexistence of material A and material B, material A and There are seven combinations of materials in the form of material C coexistence, material B and material C coexistence, or material A, material B and material C coexistence.

[Second Organization-2]
The sputtering target according to this embodiment has a second structure and the material is an alloy, has a second structure and the material is a nitride, or has a second structure and the material is a combination of an alloy and a nitride. Here, the material is a combination of the seven materials listed in [First structure].

[Third Organization-2]
The sputtering target according to the present embodiment has a third structure, and the composite phase is a composite of metal phases, and has a third structure, and the composite phase is a composite of nitride phases. Alternatively, a form of having a third structure and the composite phase being a composite of a metal phase and a nitride phase is exemplified. Here, "the composite phase is a composite of metal phases" means a composite phase containing an Al phase and an RE phase, a composite phase containing an Al phase and a TI phase, or an Al phase, an RE phase, and a TI phase. Composite phase is meant. "The composite phase is a composite of nitride phases" means a composite phase containing an AlN phase and a REN phase, a composite phase containing an AlN phase and a TIN phase, or a composite phase containing an AlN phase, a REN phase and a TIN phase. means phase. Further, "the composite phase is a composite of a metal phase and a nitride phase" means, for example, a composite phase containing an Al phase and a REN phase, a composite phase containing an AlN phase and an RE phase, an Al phase and an AlN phase and RE phase, composite phase containing Al phase, AlN phase and REN phase, composite phase containing Al phase, RE phase and REN phase, composite phase containing AlN phase, RE phase and REN phase , a composite phase containing an Al phase, an AlN phase, an RE phase and a REN phase, a composite phase containing an Al phase and a TIN phase, a composite phase containing an AlN phase and a TI phase, an Al phase, an AlN phase and a TI phase composite phase containing Al phase, AlN phase and TIN phase, composite phase containing Al phase, TI phase and TIN phase, composite phase containing AlN phase, TI phase and TIN phase, Al phase and AlN A composite phase containing a phase, a TI phase, and a TIN phase, a composite phase containing an Al phase, an AlN phase, an RE phase, and a TI phase, a composite phase containing an Al phase, an AlN phase, a REN phase, and a TI phase, and an Al phase Composite phase containing AlN phase, RE phase and TIN phase Composite phase containing Al phase, AlN phase, REN phase and TIN phase Composite phase containing Al phase, RE phase, REN phase and TI phase, AlN phase and RE phase, REN phase and TI phase, composite phase containing Al phase, RE phase, REN phase and TIN phase, composite phase containing AlN phase, RE phase, REN phase and TIN phase, Al A composite phase containing a phase, an RE phase, a TI phase, and a TIN phase, a composite phase containing an AlN phase, an RE phase, a TI phase, and a TIN phase, a composite phase containing an Al phase, a REN phase, a TI phase, and a TIN phase, Composite phase containing AlN phase, REN phase, TI phase and TIN phase Composite phase containing Al phase, AlN phase, RE phase, REN phase and TI phase Al phase, AlN phase, RE phase, REN phase and TIN phase, composite phase containing Al phase, AlN phase, RE phase, TI phase and TIN phase, composite phase containing Al phase, AlN phase, REN phase, TI phase and TIN phase, Al phase and Composite phase containing RE phase, REN phase, TI phase and TIN phase, composite phase containing AlN phase, RE phase, REN phase, TI phase and TIN phase, or Al phase, AlN phase, RE phase and REN phase , a TI phase and a TIN phase. Note that the notation of the valence is omitted.

In this embodiment, the term "metallic phase" is a concept of a phase consisting of a single metallic element.

In this embodiment, the term "nitride phase" is a concept of a phase composed of nitrides.

[Fourth Organization-2]
The sputtering target according to the present embodiment has a fourth structure, and the composite phase is a composite of an alloy phase and a metal phase, and the composite phase has an alloy phase and nitriding It has a fourth structure, which is a composite of a physical phase, and the composite phase is a composite of a nitride phase and a metal phase, and the composite phase is different from the nitride phase. Examples include a form of a composite of a nitride phase, or having a fourth structure and the composite phase being a composite of an alloy phase, a metal phase and a nitride phase. Here, the metallic phase is the phase G, the phase H and the phase I which are in the state of metal without being nitrided or oxidized, and the alloy phase is the phase D, the phase E and the phase F respectively. A phase in the state of an alloy without being nitrided or oxidized, and a nitride phase is a phase in which phase G, phase H, phase I, phase D, phase E, and phase F are each nitrided. be. In addition, the metal phase, alloy phase, and nitride phase may each exist in one type or two or more types in the target, and more than one metal phase, alloy phase, and nitride phase may exist in combination. Sometimes. Examples of these morphologies include, for example, at least one phase of a phase D alloy phase or a phase D nitride phase, a phase G metallic phase, a phase G nitride phase, a phase H metallic phase, a phase H nitriding phase. a phase comprising at least one of a physical phase, a phase I metal phase, a phase I nitride phase, a phase G metal phase in at least one phase of a phase E alloy phase or a phase E nitride phase; a morphology comprising at least one of a nitride phase, a phase H metallic phase, a phase H nitride phase, a phase I metallic phase, a phase I nitride phase, a phase F alloy phase or a phase F nitride phase; A form in which at least one phase includes at least one of a phase G metallic phase, a phase G nitride phase, a phase H metallic phase, a phase H nitride phase, a phase I metallic phase, and a phase I nitride phase There is

In this embodiment, the term "alloy phase" is a concept of a phase composed of an alloy.

[Fifth Organization-2]
The sputtering target according to the present embodiment has a fifth structure, and the composite phase has a fifth structure that is a composite of an aluminum matrix and at least one metal phase, and The composite phase is a composite of an aluminum matrix and at least one nitride phase selected from an aluminum nitride phase, a rare earth element nitride phase, and a titanium group element nitride phase, or has a fifth structure. and the composite phase is a composite of a metal phase and a nitride phase. By "at least one metallic phase" herein is meant phase H only, phase I only, or both phase H and phase I. "The composite phase is a composite of an aluminum matrix and at least one nitride phase out of an aluminum nitride phase, a rare earth element nitride phase, and a titanium group element nitride phase" means, for example, an Al matrix and REN phase, composite phase containing Al matrix phase and TIN phase, composite phase containing Al matrix phase, AlN phase and REN phase, composite phase containing Al matrix phase, AlN phase and TIN phase , a composite phase containing an Al matrix phase, a REN phase and a TIN phase, or a composite phase containing an Al matrix phase, an AlN phase, a REN phase and a TIN phase. "The composite phase is a composite of a metal phase and a nitride phase" means, for example, a composite phase containing an Al matrix phase, an RE phase and a TIN phase, a composite phase containing an Al matrix phase, a REN phase and a TI phase , a composite phase containing an Al matrix phase, an AlN phase, an RE phase, and a TI phase, a composite phase containing an Al matrix phase, an AlN phase, a REN phase, and a TI phase, an Al matrix phase, an AlN phase, an RE phase, and a TIN phase a composite phase containing an Al matrix phase, an RE phase, a REN phase, and a TI phase, a composite phase containing an Al matrix phase, an RE phase, a REN phase, and a TIN phase, an Al matrix phase, an RE phase, and a TI phase and TIN phase, composite phase containing Al matrix phase, REN phase, TI phase and TIN phase, composite phase containing Al matrix phase, AlN phase, RE phase, REN phase and TI phase, Al matrix A composite phase containing a phase, an AlN phase, an RE phase, a REN phase, and a TIN phase, a composite phase containing an Al matrix phase, an AlN phase, an RE phase, a TI phase, and a TIN phase, an Al matrix phase, an AlN phase, and a REN phase A composite phase containing a TI phase and a TIN phase, a composite phase containing an Al matrix phase, an RE phase, a REN phase, a TI phase, and a TIN phase, or an Al matrix phase, an AlN phase, an RE phase, a REN phase, and a TI phase A composite phase comprising a TIN phase. In addition, N means a nitrogen element, and for example, "AlN phase" means an aluminum nitride phase. In addition, the notation of the valence of the nitride is omitted.

In the fifth structure-2, a mode is included in which the composite phase is a composite of a nitride phase further containing an aluminum nitride phase. That is, the composite phase in the fifth structure-2 is a composite phase to which the AlN phase is added in each of the morphological examples listed in the fifth structure. Specifically, among the fifth organization-2, as this embodiment, in particular,
(1) "The composite phase is a composite of an aluminum matrix and at least one nitride phase among an aluminum nitride phase, a rare earth element nitride phase, and a titanium group element nitride phase" is an Al matrix and an AlN phase and a REN phase, a composite phase containing an Al matrix phase, an AlN phase and a TIN phase, or a composite phase containing an Al matrix phase, an AlN phase, a REN phase and a TIN phase, When,
(2) "The composite phase is a composite of a metal phase and a nitride phase" is a composite phase containing an Al matrix phase, an AlN phase, an RE phase and a TI phase, an Al matrix phase, an AlN phase, a REN phase and a TI a composite phase containing an Al matrix phase, an AlN phase, an RE phase, and a TIN phase, a composite phase containing an Al matrix phase, an AlN phase, an RE phase, a REN phase, and a TI phase, and an Al matrix phase Composite phase containing AlN phase, RE phase, REN phase and TIN phase Composite phase containing Al matrix phase, AlN phase, RE phase, TI phase and TIN phase, Al matrix phase, AlN phase, REN phase and TI phase and a TIN phase, or a composite phase including an Al matrix phase, an AlN phase, an RE phase, a REN phase, a TI phase, and a TIN phase.

In the sputtering target according to the present embodiment, an intermetallic compound composed of at least two elements selected from aluminum, rare earth elements and titanium group elements is preferably present in the sputtering target. For example, such intermetallic compounds are present in the sputtering target in the first texture or the second texture. Further, when an alloy phase exists in the fourth structure, an intermetallic compound exists in the alloy phase. Variation in composition can be suppressed by reducing the number of portions containing aluminum as an element, a rare earth element as an element, or a titanium group element as an element. In addition, when the target is composed of a combination of single metals, the sputtering rate for each single metal is applied during sputtering, resulting in a significant difference, making it difficult to obtain a uniform film. If there is, the difference in sputtering rate between the metal elements is reduced, and the compositional unevenness of the obtained film is reduced.

In the sputtering target according to this embodiment, one, two, three, or four types of intermetallic compounds may be present in the sputtering target. For example, when an alloy phase exists in the first structure, the second structure, or the fourth structure, one, two, three, or four types of metals are included in the sputtering target according to the number of types of metal species. of intermetallic compounds are present. When the target is composed of a combination of metal simple substances, the sputtering rate for each single metal is applied during sputtering, and the difference is remarkable, so it is difficult to obtain a homogeneous film. The presence of a plurality of types of metal elements further reduces the difference in sputtering rate between the metal elements, and the compositional unevenness of the obtained film is further reduced.

In the sputtering target according to the present embodiment, one or more nitrides of at least one element selected from aluminum, rare earth elements and titanium group elements may be present in the sputtering target. When the nitride film of the piezoelectric element is formed, it is possible to cope with an increase in temperature of the piezoelectric element and to increase the Q value. For example, nitrides are present in any of the first structure to the fifth structure by introducing a nitrogen element. There are 1, 2, 3, 4, or more types of nitrides depending on the number of types of metal species.

In the sputtering target according to this embodiment, the rare earth element is preferably at least one of scandium and yttrium. When the nitride film of the piezoelectric element is formed, it is possible to cope with an increase in temperature of the piezoelectric element and to increase the Q value. As rare earth elements there are scandium only, yttrium only, or a combination of both scandium and yttrium. When both scandium and yttrium are included as rare earth elements, for example, Al-Sc-Y materials or Al-Sc-Y phases, as well as Al-Sc materials, Al-Y materials and Al-Sc-Y materials or a form in which at least two phases of an Al--Sc phase, an Al--Y phase and an Al--Sc--Y phase exist simultaneously.

In the sputtering target according to this embodiment, the titanium group element is preferably at least one of titanium, zirconium and hafnium. When the nitride film of the piezoelectric element is formed, it is possible to cope with an increase in temperature of the piezoelectric element and to increase the Q value. Titanium group elements include titanium only, zirconium only, hafnium only, titanium and zirconium, titanium and hafnium, zirconium and hafnium, or titanium, zirconium and hafnium. As a titanium group element, for example, when both titanium and zirconium are included, for example, Al--Ti--Zr materials or Al--Ti--Zr phases, as well as Al--Ti materials, Al--Zr materials and Al-- There is a form in which at least two kinds of Ti--Zr materials exist simultaneously, or a form in which at least two phases of Al--Ti phase, Al--Zr phase and Al--Ti--Zr phase exist simultaneously. Further, when both titanium and hafnium are included, for example, in addition to Al-Ti-Hf materials or forms in which Al-Ti-Hf phases are present, Al-Ti materials, Al-Hf materials and Al-Ti-Hf materials There is a form in which at least two kinds of materials exist simultaneously, or a form in which at least two kinds of phases of an Al--Ti phase, an Al--Hf phase and an Al--Ti--Hf phase exist simultaneously. In addition, when both zirconium and hafnium are included, for example, in addition to Al-Zr-Hf materials or forms in which Al-Zr-Hf phases exist, Al-Zr materials, Al-Hf materials and Al-Zr-Hf materials There is a form in which at least two kinds of materials exist simultaneously, or a form in which at least two phases of an Al--Zr phase, an Al--Hf phase and an Al--Zr--Hf phase exist simultaneously. When titanium, zirconium and hafnium are included, for example, Al-Ti-Zr-Hf material or a form in which Al-Ti-Zr-Hf phase exists, Al-Ti material, Al-Zr material, Al-Hf material, Al--Ti--Zr material, Al--Ti--Hf material, Al--Zr--Hf material and Al--Ti--Zr--Hf material, or Al--Ti phase, Al-- A form in which at least two phases of a Zr phase, an Al--Hf phase, an Al--Ti--Zr phase, an Al--Ti--Hf phase, an Al--Zr--Hf phase and an Al--Ti--Zr--Hf phase are present at the same time, and further , a form in which a material or phase containing two of Ti, Zr and Hf in addition to Al is added to the above forms, and a material or phase containing one of Ti, Zr and Hf in addition to Al is further added There is a form.

In the sputtering target according to the present embodiment, rare earth elements contained in aluminum include scandium and yttrium, and titanium group elements contained in aluminum include titanium, zirconium, and hafnium. The content of scandium in the target is preferably 5 to 75 atomic %. More preferably, it is 10 to 50 atomic %. The yttrium content in the target is preferably 5 to 75 atomic %. More preferably, it is 10 to 50 atomic %. The content of titanium in the target is preferably 5 to 75 atomic %. More preferably, it is 10 to 50 atomic %. The zirconium content in the target is preferably 5 to 75 atomic %. More preferably, it is 10 to 50 atomic %. The hafnium content in the target is preferably 5 to 75 atomic %. More preferably, it is 10 to 50 atomic %. The sputtering target according to the present embodiment contains at least one kind of each of the above elements together with aluminum so as to satisfy the above contents.

When forming an alloy containing a rare earth element and a titanium group element in aluminum, first, an aluminum-rare earth element alloy such as an aluminum-scandium alloy or an aluminum-yttrium alloy is formed within the above composition range. Next, an alloy of an aluminum-titanium group element such as an aluminum-titanium alloy, an aluminum-zirconium alloy, an aluminum-hafnium alloy, etc. is formed within the above composition range. Thereafter, the aluminum-rare earth element alloy and the aluminum-titanium group element alloy are mixed while adjusting the respective contents to form an aluminum-rare earth element-titanium group element alloy. Alternatively, instead of mixing binary alloys to form a ternary alloy as described above, an aluminum-rare earth element-titanium group element alloy may be directly formed. By forming an intermetallic compound in the sputtering target and forming a nitride film during sputtering, it is possible to form a piezoelectric film having a high Q value even at high temperatures.

A method for manufacturing a sputtering target according to this embodiment will be described. The method for producing a sputtering target according to the present embodiment includes (1) a raw material composed of aluminum and a rare earth element, (2) a raw material composed of aluminum and a titanium group element, or (3) aluminum, a rare earth element, and a titanium group element. and from the raw material produced in the first step, (1) an alloy powder of aluminum and a rare earth element (aluminum-rare earth element), (2) aluminum and a titanium group element A second step of producing an alloy powder (aluminum-titanium group element) of (3) aluminum, a rare earth element and a titanium group element (aluminum-rare earth element-titanium group element), and the second (1) aluminum-rare earth element sintered body, (2) aluminum-titanium group element sintered body, and (3) aluminum-rare earth element-titanium group element sintered body are obtained from the powder obtained in the process. and In the case of manufacturing a sputtering target containing an aluminum matrix, the method of manufacturing the sputtering target is to use an aluminum raw material that is mainly to be the matrix and a material that is mainly present in the matrix or a raw material that is to be the phase. A first step of producing (1) a raw material composed of aluminum and a rare earth element, (2) a raw material composed of aluminum and a titanium group element, or (3) a raw material composed of aluminum, a rare earth element, and a titanium group element and an aluminum powder that is mainly to be the matrix phase from the raw material produced in the first step, and an alloy powder that is mainly to be the material or phase that is present in the matrix phase (1) an alloy of aluminum and a rare earth element powder (aluminum-rare earth element), (2) alloy powder of aluminum and titanium group element (aluminum-titanium group element), or (3) alloy powder of aluminum, rare earth element and titanium group element (aluminum-rare earth element -Titanium group element), and from the powder obtained in the second step, (1) aluminum and aluminum-rare earth element sintered body, (2) aluminum and aluminum-titanium group element sintered or (3) a third step of obtaining a sintered body of aluminum and aluminum-rare earth element-titanium group element.

[First step]
This step is a step of producing the raw material used in the second step to produce the aluminum-rare earth element alloy powder, the aluminum-titanium group element alloy powder, or the aluminum-rare earth element-titanium group element alloy powder. . The raw material for producing the powder (hereinafter also simply referred to as "raw material") to be produced in the first step is (1A) preparing single metals of the constituent elements of the alloy target as starting raw materials, and mixing them. (2A) A form in which an alloy having the same composition as the alloy target is prepared as a starting raw material and this is used as a raw material, or (3A) As a starting raw material, the alloy target has the same or partially missing constituent elements. An example is a form in which an alloy having a composition ratio different from the desired composition ratio and a single metal blended to adjust the composition to the desired composition are prepared and mixed to form a raw material. As starting raw materials, aluminum and rare earth elements, aluminum and titanium group elements, or aluminum and rare earth elements and titanium group elements are put into a melting apparatus and melted to obtain aluminum-rare earth element alloy raw materials, aluminum-titanium. A raw material for an alloy of group elements or a raw material for an aluminum-rare earth element-titanium group element alloy is prepared. After melting, the melting apparatus is designed so that a large amount of impurities are not mixed into the raw material of the aluminum-rare earth element alloy, the raw material of the aluminum-titanium group element alloy, or the raw material of the aluminum-rare earth element-titanium group element alloy. It is preferable to use materials containing few impurities for the equipment and container to be used. As the dissolution method, a method that can correspond to the following dissolution temperature is selected. As the melting temperature, an aluminum-rare earth element alloy is heated at 1,300 to 1,800.degree. C., an aluminum-titanium group element alloy is heated at 1,300 to 1,800.degree. The atmosphere in the melting apparatus may be a vacuum atmosphere with a degree of vacuum of 1×10 ⁻² Pa or less, a nitrogen gas atmosphere containing 4 vol % or less of hydrogen gas, or an inert gas atmosphere containing 4 vol % or less of hydrogen gas. When producing an aluminum raw material, such as when an aluminum mother phase is included in a target, aluminum is heated at 700 to 900° C. and charged into a melting apparatus to produce the same as other raw materials.

In addition to the three raw material forms described in (1A), (2A), and (3A) above, the raw material form of the alloy powder may be alloy grains or alloy lumps, or a combination of powder, grains, and lumps. good too. Powder, granules, and lumps express differences in particle size, but any of them is not particularly limited as long as it can be used in the powder manufacturing apparatus in the second step. Specifically, since the raw material is melted in the powder manufacturing apparatus in the second step, there is no particular limitation as long as the size of the raw material can be supplied to the powder manufacturing apparatus.

[Second step]
This step is a step of producing aluminum-rare earth element alloy powder, aluminum-titanium group element alloy powder, or aluminum-rare earth element-titanium group element alloy powder. At least one of the raw materials for the aluminum-rare earth element alloy, the raw material for the aluminum-titanium group element alloy, or the raw material for the aluminum-rare earth element-titanium group element alloy produced in the first step is supplied to the powder production apparatus. After the material is put in and melted to form a molten metal, gas or water is sprayed onto the molten metal to scatter the molten metal and rapidly solidify to produce a powder. A powder manufacturing apparatus is provided so that a large amount of impurities are not mixed into the aluminum-rare earth element alloy powder, the aluminum-titanium group element alloy powder, or the aluminum-rare earth element-titanium group element alloy powder after melting. It is preferable to use materials containing few impurities for the equipment and container to be used. As the dissolution method, a method that can correspond to the following dissolution temperature is selected. The melting temperature is 1,300 to 1,800° C. for an aluminum-rare earth element alloy raw material, 1,300 to 1,800° C. for an aluminum-titanium group element alloy, or 1,300 to 1,800° C. for an aluminum-rare earth element-titanium group element alloy. Heat the raw materials for the alloy. The atmosphere in the powder manufacturing apparatus is a vacuum atmosphere with a degree of vacuum of 1×10 ⁻² Pa or less, a nitrogen gas atmosphere containing 4 vol % or less of hydrogen gas, or an inert gas atmosphere containing 4 vol % or less of hydrogen gas. The temperature of the molten metal when spraying should be "the melting point of aluminum-rare earth element alloy, aluminum-titanium group element alloy, or aluminum-rare earth element-titanium group element alloy + 100 ° C or higher". is preferred, and it is more preferred to carry out at "the melting point of aluminum-rare earth element alloy, aluminum-titanium group element alloy, or aluminum-rare earth element-titanium group element alloy +150 to 250° C.". This is because if the temperature is too high, cooling during granulation is not sufficiently performed, making it difficult to form a powder, resulting in poor production efficiency. On the other hand, if the temperature is too low, the problem of nozzle clogging during injection tends to occur. Nitrogen, argon, or the like is used as a gas for blowing, but is not limited thereto. In the case of alloy powder, precipitation of intermetallic compounds in the alloy powder is suppressed by rapid solidification compared to the dissolution method. This state is already obtained at the stage of , and is maintained even after sintering and when the target is formed. The quenched powder has the element ratio of aluminum and rare earth element, aluminum and titanium group element, or aluminum, rare earth element and titanium group element prepared in the first step. When aluminum powder is to be produced, for example, when an aluminum matrix is included in a target, aluminum is heated at 700 to 900° C. and charged into a melting apparatus to be produced in the same manner as other powders.

[Third step]
This step is a step of obtaining a sintered body as a target from the powder obtained in the second step. As the sintering method, sintering is performed by a hot press method (hereinafter also referred to as HP), a spark plasma sintering method (hereinafter also referred to as SPS), or a hot isostatic sintering method (hereinafter also referred to as HIP). knot. The aluminum-rare earth element alloy powder, the aluminum-titanium group element alloy powder, or the aluminum-rare earth element-titanium group element alloy powder obtained in the second step is sintered. The powder used for sintering is the following case.
(1B) In the case of an aluminum-rare earth element alloy, an aluminum-rare earth element alloy powder is used.
(2B) In the case of an aluminum-titanium group element alloy, an aluminum-titanium group element alloy powder is used.
(3B) In the case of an aluminum-rare earth element-titanium group element alloy, for example, an aluminum-rare earth element-titanium group element alloy powder is used, or an aluminum-rare earth element alloy powder and an aluminum-titanium group element alloy powder are used. A mixed powder obtained by mixing two types of is used.
It is preferable to pack any one of the powders shown in (1B) to (3B) above into a mold, pre-pressurize the mold to 10 to 30 MPa, seal the powder with a punch or the like, and then sinter. At this time, the sintering temperature is preferably 700 to 1300° C., and the applied pressure is preferably 40 to 196 MPa. The atmosphere in the sintering apparatus is a vacuum atmosphere with a degree of vacuum of 1×10 ⁻² Pa or less, a nitrogen gas atmosphere containing 4 vol % or less of hydrogen gas, or an inert gas atmosphere containing 4 vol % or less of hydrogen gas. Hydrogen gas is preferably contained in an amount of 0.1 vol % or more. The holding time (holding time at the highest sintering temperature) is preferably 2 hours or less, more preferably 1 hour or less, and still more preferably no holding time. When aluminum powder is mixed with the alloy powder of (1B), (2B) or (3B) in the case where the aluminum mother phase is included in the target, etc., the sintering temperature is set to 500 to 600 ° C. Sintering under similar conditions is preferred.

By performing at least the first step to the third step, it is possible to suppress the composition deviation in the in-plane direction and the thickness direction of the sputtering target, and to manufacture a sputtering target with a low content of impurities that affect thin film formation. Furthermore, a sputtering target with a low chlorine content can be produced.

The method for manufacturing a sputtering target according to this embodiment also includes the following modifications. That is, in the first step, an aluminum raw material to be mainly used as a matrix phase and a material or phase mainly present in the matrix phase as (1) a rare earth element raw material, (2) a titanium group element raw material, or (3) You may manufacture the raw material which consists of a rare earth element and a titanium group element. In the second step, each raw material produced in the first step may be atomized powder. In the third step, from the raw material obtained in the first step or the powder obtained in the second step, (1) a sintered body of aluminum and a rare earth element, (2) a sintered body of aluminum and a titanium group element, or (3) Obtaining a sintered body of aluminum and a rare earth element-titanium group element.

In this embodiment, the method of composition analysis in (Condition 1) and (Condition 2) is energy dispersive X-ray spectroscopy (EDS), high frequency inductively coupled plasma atomic emission spectroscopy (ICP), fluorescent X-ray analysis ( XRF), etc., but composition analysis by EDS is preferred.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention should not be construed as being limited to the examples.

(Example 1)
An Al raw material with a purity of 4N and an Sc raw material with a purity of 3N are put into a powder production apparatus, then the inside of the powder production apparatus is adjusted to a vacuum atmosphere of 5 × 10 ^-3 Pa or less, and the Al raw material and the Al raw material are melted at a melting temperature of 1700 ° C. The Sc raw material is melted to form a molten metal, then argon gas is blown onto the molten metal, the molten metal is scattered and rapidly solidified to obtain Al-40 atomic % Sc powder with a particle size of 150 μm or less (in this case, Al is 60 atoms % Al, but the description of the atomic percentage of Al is omitted. After that, the Al-40 atomic % Sc powder was filled in a carbon mold for spark plasma sintering (hereinafter also referred to as SPS sintering). Next, the powder mixture was sealed with a punch or the like under a pre-pressurization of 10 MPa, and the mold filled with the powder mixture was placed in an SPS apparatus (model number: SPS-825, manufactured by SPS Syntex). As sintering conditions, the sintering temperature is 550° C., the pressure is 30 MPa, the atmosphere in the sintering apparatus is a vacuum atmosphere of 8×10 ⁻³ Pa or less, and the maximum sintering temperature is held for 0 hours. Sintering was carried out at The Al-40 atomic % Sc sintered body was processed using a grinding machine, a lathe, etc. to prepare an Al-40 atomic % Sc target of Example 1 of Φ50.8 mm×5 mmt. Next, a cross section of the Al-40 atomic % Sc target was observed with an electron microscope at a magnification of 500 times. FIG. 7 shows the observed electron microscope image. The length of the horizontal side of the image in FIG. 7 is 250 μm. As a result of FIG. 7, it was confirmed that the contrast was small and the intermetallic compound was fine and uniformly dispersed. Further, as a result of the electron microscope image in FIG. 7, the target was composed of two kinds of intermetallic compounds, Al ₂ Sc and AlSc, and had the first structure. Next, the chlorine content of the Al-40 atomic % Sc target of Example 1 was measured using a mass spectrometer (model number: Element GD, manufactured by Thermo Fisher Scientific). The chlorine content was 5.6 ppm. Next, using the Al-40 atomic % Sc target of Example 1, a film was formed on a single-crystal Si substrate of φ76.2 mm×5 mmt using a sputtering device (model number MPS-6000-C4, manufactured by ULVAC). The film formation conditions were such that the interior of the sputtering device was evacuated to reach a degree of vacuum of 5×10 ⁻⁵ Pa or less before film formation, and then the pressure within the sputtering device was adjusted to 0.13 Pa using Ar gas. Thereafter, while heating the single crystal Si substrate to 300° C., the sputtering power of the Al-40 atomic % Sc target was adjusted to 150 W to form an Al-40 atomic % Sc film with a thickness of 1 μm on the single crystal Si substrate. At this time, the state of sputtering of the Al-40 atomic % Sc target was observed, and the voltage was stable, and the film could be formed without confirming abnormal discharge.

(Example 2)
In Example 1, instead of the Al-40 atomic% Sc powder, Al-30 atomic% Sc powder with a particle size of 150 μm or less was produced, and instead of the Al-40 atomic% Sc target of Example 1, Φ50.8 mm × An Al-30 atomic % Sc target of Example 2 was obtained in the same manner, except that a 5 mmt Al-30 atomic % Sc target was produced. Next, the chlorine content of the Al-30 atomic % Sc target of Example 2 was measured in the same manner as in Example 1. The chlorine content was 3.7 ppm. The target consisted of two types of intermetallic compounds, Al ₂ Sc and AlSc, and had a first texture. Next, in the same manner as in Example 1 except that the Al-30 atomic % Sc target of Example 2 was used instead of the Al-40 atomic % Sc target of Example 1, Al-30 was deposited on the single crystal Si substrate. An atomic % Sc film was formed with a thickness of 1 μm. At this time, the state of sputtering of the Al-30 atomic % Sc target was observed, and the voltage was stable, and the film could be formed without confirming abnormal discharge or the like.

( Reference example 3)
Al-40 atoms with a particle size of 150 μm or less in the same manner as in Example 1, except that instead of using the Al raw material with a purity of 4N and the Sc raw material with a purity of 3N, an Al raw material with a purity of 4N and a Ti raw material with a purity of 3N were used. %Ti powder was prepared. Next, in the same manner as in Example 1, except that an Al-40 atomic% Ti target of Φ50.8 mm × 5 mmt was produced instead of the Al-40 atomic% Sc target of Example 1. Al-40 of Reference Example 3 An atomic % Ti target was obtained. Next, the chlorine content of the Al-40 atomic % Ti target of Reference Example 3 was measured in the same manner as in Example 1. The chlorine content was 4.0 ppm. The target consisted of two types of intermetallic compounds, Al ₂ Ti and AlTi, and had a first texture. Next, in the same manner as in Example 1, except that the Al-40 atomic % Ti target of Reference Example 3 was used instead of the Al-40 atomic % Sc target of Example 1, Al-40 was deposited on the single crystal Si substrate. An atomic % Ti film was formed with a thickness of 1 μm. At this time, the state of the sputtering of the Al-40 atomic % Ti target was observed, and the voltage was stable, and the film could be formed without confirming abnormal discharge or the like.

(Comparative example 1)
A pure Al powder with a particle size of 150 μm or less and a purity of 3N and a Sc powder with a particle size of 150 μm or less and a purity of 2N are used, and the amounts of each powder are adjusted so that Al-40 atomic % Sc is obtained, and mixed. rice field. After that, the Al-40 atomic % Sc mixed powder was filled into a carbon mold for SPS sintering. Next, the powder mixture was sealed with a punch or the like under a pre-pressurization of 10 MPa, and the mold filled with the powder mixture was placed in an SPS apparatus (model number: SPS-825, manufactured by SPS Syntex). As sintering conditions, the sintering temperature is 550° C., the pressure is 30 MPa, the atmosphere in the sintering apparatus is a vacuum atmosphere of 8×10 ⁻³ Pa or less, and the maximum sintering temperature is held for 0 hours. Sintering was carried out at The Al-40 atomic % Sc sintered body after sintering was processed using a grinder, a lathe, etc., and an Al-40 atomic % Sc target of Φ50.8 mm×5 mmt of Comparative Example 1 was produced. Next, the chlorine content of the Al-40 atomic % Sc target of Comparative Example 1 was measured in the same manner as in Example 1. The chlorine content was 146 ppm. The target consisted of two types of intermetallic compounds, Al ₂ Sc and AlSc, and had a first texture. Next, in the same manner as in Example 1 except that the Al-40 atomic % Sc target of Comparative Example 1 was used instead of the Al-40 atomic % Sc target of Example 1, Al-40 was deposited on the single crystal Si substrate. An atomic % Sc film was formed with a thickness of 1 μm. At this time, when the state of sputtering of the Al-40 atomic % Sc target of Comparative Example 1 was observed, the voltage was not stable and abnormal discharge was confirmed. A possible cause of the abnormal discharge compared to Example 1 is that chlorine in the sputtering target was released by heating during film formation.

(Comparative example 2)
In Comparative Example 1, in the same manner as in Comparative Example 1, except that the amount of each powder was adjusted so that Al-30 atomic% Sc instead of Al-40 atomic% Sc. In addition, an Al-30 atomic % Sc target of Φ50.8 mm×5 mmt of Comparative Example 2 was produced. Next, the chlorine content of the Al-30 atomic % Sc target of Comparative Example 2 was measured in the same manner as in Example 1. The chlorine content was 180 ppm. The target consisted of two types of intermetallic compounds, Al ₂ Sc and AlSc, and had a first texture. Next, in the same manner as in Example 1 except that the Al-30 atomic % Sc target of Comparative Example 2 was used instead of the Al-40 atomic % Sc target of Example 1, Al-30 was deposited on the single crystal Si substrate. An atomic % Sc film was formed with a thickness of 1 μm. At this time, when the state of sputtering of the Al-30 atomic % Sc target of Comparative Example 2 was observed, the voltage was not stable and abnormal discharge was confirmed. A possible cause of the abnormal discharge compared to Example 2 is that chlorine in the sputtering target was released by heating during film formation.

(Comparative Example 3)
In Comparative Example 1, pure Al powder with a particle size of 150 μm or less and a purity of 3N and Sc powder with a particle size of 150 μm or less and a purity of 2N are used, and the amount of each powder is adjusted so that Al-40 atomic % Sc. Instead, a pure Al powder with a particle size of 150 μm or less and a purity of 3N and a Ti powder with a particle size of 150 μm or less and a purity of 2N were used so that the amount of each powder was adjusted to Al-40 atomic % Ti. Similarly, an Al-40 atomic % Ti target of Φ50.8 mm×5 mmt of Comparative Example 3 was produced. Next, the chlorine content of the Al-40 atomic % Ti target of Comparative Example 3 was measured in the same manner as in Example 1. The chlorine content was 216 ppm. The target consisted of two types of intermetallic compounds, Al ₂ Ti and AlTi, and had a first texture. Next, in the same manner as in Example 1 except that the Al-40 atomic % Ti target of Comparative Example 3 was used instead of the Al-40 atomic % Sc target of Example 1, Al-40 was deposited on the single crystal Si substrate. An atomic % Ti film was formed with a thickness of 1 μm. At this time, when the state of sputtering of the Al-40 atomic % Ti target of Comparative Example 3 was observed, the voltage was not stable and abnormal discharge was confirmed. A possible cause of the abnormal discharge compared to Reference Example 3 is that chlorine in the sputtering target was released by heating during film formation.

(Comparative Example 4)
An Al raw material with a purity of 4N and a Sc raw material with a purity of 3N were weighed so as to be Al-40 atomic % Sc, melted with an arc melting apparatus (AME-300 type manufactured by ULVAC), and melted to about 60 mm square × 6 mm. got a board Next, we tried to machine this plate to produce a sputtering target of Φ50.8 mm × 5 mmt, but chipping occurred on the outer periphery of the plate during grinding, and cracks occurred in the plate during cutting by wire electric discharge machining. , could not produce a sputtering target. In order to confirm the cause of crack generation, the cross section of the Al-40 atomic % Sc target was observed with an electron microscope at a magnification of 500 times. FIG. 8 shows the observed electron microscope image. The length of the horizontal side of the image in FIG. 8 is 250 μm. As a result of FIG. 8, although the discontinuous surface at the upper end is the processing surface of the target, cracks were confirmed inside the intermetallic compound. For this reason, it is considered that cracks tend to occur starting from coarsened intermetallic compound particles, resulting in poor workability.

Table 1 shows the types of elements added to Al, the amount of added elements, and the content of chlorine for Examples 1 and 2, Reference Example 3, and Comparative Examples 1 to 3. By comparing Example 1 with Comparative Example 1, Example 2 with Comparative Example 2, and Reference Example 3 with Comparative Example 3, as described above, even if the types and amounts of additive elements to Al are the same, It has been found that abnormal discharge occurs during film formation unless the chlorine content is a predetermined value (100 ppm or less).

In Comparative Example 4, the plate was produced only by the dissolution method, so the obtained plate had a structure in which the intermetallic compound was coarsened. As a result, the intermetallic compound became brittle, and chipping and cracking occurred from the brittle intermetallic compound during processing. On the other hand, in Example 1, by performing granulation by melting and rapid solidification, the intermetallic compound was suppressed from becoming a coarse structure. This is thought to be due to the fact that a fine structure is maintained, chipping and cracking are suppressed, and workability is improved. In the sputtering target of Example 1, the fine structure is maintained, so that the composition deviation depending on the location in the target is small. In order to confirm the composition deviation, the composition of the sputtering target in the sputtering in-plane direction and the target thickness direction under (Condition 1) was confirmed. The composition was measured using EDS (manufactured by JEOL Ltd.). As a result, it was confirmed that the difference in each composition was within ±1% with respect to the reference composition, and the composition deviation was small. On the other hand, in Comparative Example 4, depending on the measurement points, there were places where the difference from the reference composition did not fall within ±3%.

In Example 1, the fluorine content was measured using a mass spectrometer (model number: Element GD, manufactured by Thermo Fisher Scientific). The fluorine content was 5.5 ppm. Also, in Comparative Example 1, the fluorine content was measured in the same manner. The fluorine content was 130 ppm.

In Example 1, the oxygen content was measured using a mass spectrometer (model number: ON836, manufactured by LECO). The oxygen content was 424 ppm. Also, in Comparative Example 1, the oxygen content was measured in the same manner. The oxygen content was 2993 ppm.

(Example 4)
A pure Al powder with a particle size of 150 μm or less and a purity of 4N and an ScN powder with a particle size of 150 μm or less and a purity of 3N were used, and the amounts of each powder were adjusted so that Al-10 mol % ScN was obtained, followed by mixing. . After that, the Al-10 mol % ScN mixed powder was filled in a carbon mold for spark plasma sintering (hereinafter also referred to as SPS sintering). Next, the powder mixture was sealed with a punch or the like under a pre-pressurization of 10 MPa, and the mold filled with the powder mixture was placed in an SPS apparatus (model number: SPS-825, manufactured by SPS Syntex). As sintering conditions, the sintering temperature is 550° C., the pressure is 30 MPa, the atmosphere in the sintering apparatus is a vacuum atmosphere of 8×10 ⁻³ Pa or less, and the maximum sintering temperature is held for 0 hours. Sintering was carried out at The Al-10mol%ScN sintered body after sintering was processed using a grinding machine, a lathe, etc. to prepare an Al-10mol%ScN target of Φ50mm×6mmt. When the target was produced, the workability was good and it was possible to mold it into the shape of the target. The surface of the produced target was observed with a microscope. The observed image is shown in FIG. The length of the horizontal side of the image in FIG. 9 is 650 μm. From FIG. 9, it can be confirmed that Al occupies the majority of ScN, and it is considered that the aluminum matrix exists due to the presence of connected Al. As a result, it is considered that the workability at the time of target production was obtained. At this time, the target consisted of two types of phases, Al and ScN, and had the fifth texture-2.

Next, the chlorine content of the Al-10 mol % ScN target of Example 4 was measured using a mass spectrometer (model number: Element GD, manufactured by Thermo Fisher Scientific). The chlorine content was 35.4 ppm.

Next, using the Al-10 mol % ScN target of Example 4, a film was formed on a single-crystal Si substrate of φ76.2 mm×5 mmt using a sputtering device (model number MPS-6000-C4, manufactured by ULVAC). The film formation conditions were such that the interior of the sputtering device was evacuated to reach a degree of vacuum of 5×10 ⁻⁵ Pa or less before film formation, and then the pressure within the sputtering device was adjusted to 0.13 Pa using Ar gas. Thereafter, while heating the single crystal Si substrate to 300° C., the sputtering power of the Al-10 mol % ScN target was adjusted to 150 W to form an Al-10 mol % ScN film with a thickness of 1 μm on the single crystal Si substrate. At this time, the state of sputtering of the Al-10 mol % ScN target was observed, and the voltage was stable, and the film could be formed without confirming abnormal discharge or the like.

100, 200, 300, 400 Sputtering target O Center L, Q Virtual crosshairs S1 to S9 Measurement points C1 to C9 on the sputtering surface Measurement points P1 to P9 on the cross section Measurement points D1 to D9 on the sputtering surface Measurement points 1 on the cross section Al- RE alloy particles 3 Al matrix phases 2, 2a, 2b Al-RE alloy crystal grains 4, 4a, 4b Aluminum crystal grains

Claims (7)

A sputtering target containing aluminum and further containing either one or both of a rare earth element and a titanium group element,
The chlorine content is 100 ppm or less ,
The rare earth element is at least one of scandium and yttrium,
The titanium group element is at least one of zirconium and hafnium,
A sputtering target, wherein the sputtering target contains 10 to 75 atomic percent of at least one element selected from the rare earth elements and the titanium group elements . 2. The sputtering target according to claim 1, wherein the fluorine content is 100 ppm or less. 3. The sputtering target according to claim 1, wherein the oxygen content is 500 ppm or less. 4. The sputtering target according to any one of claims 1 to 3, wherein an intermetallic compound composed of at least two elements selected from aluminum, rare earth elements and titanium group elements is present in the sputtering target. sputtering target. 5. The sputtering target according to claim 4, wherein one, two, three or four types of said intermetallic compounds are present in said sputtering target. 6. The sputtering target according to any one of claims 1 to 5, wherein one or more nitrides of at least one element selected from aluminum, rare earth elements and titanium group elements are present in the sputtering target. The described sputtering target. A structure in which at least one of a material containing aluminum and a rare earth element, a material containing aluminum and a titanium group element, and a material containing aluminum, a rare earth element and a titanium group element is present in the aluminum matrix. have or
A structure composed of a composite phase containing at least one or both of a phase containing only rare earth elements and inevitable impurities as metal species and a phase containing only titanium group elements and inevitable impurities as metal species in the aluminum matrix phase The sputtering target according to any one of claims 1 to 6 , characterized in that it has

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