JPH0347963A - Sputtering target - Google Patents

Abstract

PURPOSE:To prevent the composition of a built-up film from being made ununiformed by dividing a target piece consisting of combination of a plurality of materials at every material and compositely arranging them to form the target. CONSTITUTION:The plane shape of a sputtering target 1 is formed of a rectangle. This sputtering target is constituted so that two or more kinds of rectangular materials, namely Mo piece 2 and Ta piece 3 are alternately arranged excepting both end parts of the lengthwise direction. The shape or the surface area of the Mo piece 2 and the Ta piece 3 arranged to both end parts is decided so that composition of a built-up film in both end parts is made same as composition thereof in the central part. Arrangement thereof is properly decided. Thereby the specific inaccuracy of maximum resistance in the built-up film obtained by sputtering can be regulated to about 15% or below. This sputtering target shows effect for formation of a metallic thin film utilized for a semiconductor device, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a sputtering target, and particularly to an improvement of a composite sputtering target formed by arranging target pieces divided into a plurality of types.

(Prior Art) Sputtering technology has been widely known as a technology for forming a thin film on a specific base material.

In such sputtering techniques, various attempts have been made to form thin films composed of composite components such as alloys in addition to thin films composed of single components. In these sputtering techniques, it is difficult to create a target with a composition ratio that deviates from the stoichiometric amount and has a uniform composition, such as molybdenum and silicon, or when there is a large difference in melting point or vapor pressure. When it is difficult to create an alloy target body with a predetermined composition ratio due to differences, a composite sputtering target is used in which multiple types of constituent components are divided and arranged (for example, .46631).

The above-mentioned composite targets include a disk-shaped target made by alternately combining multiple wedge-shaped target pieces, or a target body made of a rectangular plate-shaped target by alternately arranging strip-shaped target pieces. It has been known.

(Problem to be Solved by the Invention) When film deposition is performed using the composite sputtering target as described above, it is possible to freely change the composition ratio of the formed film by changing the type and combination of target pieces. It has the advantage of being possible. For example, in the case of a disk-shaped target body, since the composition ratio of the target in the radial direction is the same, the formed film composition becomes uniform, and a deposited film corresponding to the composition ratio of the target can be obtained.

However, on the other hand, if the target body is rectangular in shape and erosion due to sputtering is not uniform, there will inevitably be a difference between the composition of the formed film and the composition ratio of the target. This may result in uneven parts of the material. This will be explained in detail below.

The above phenomenon will be explained with respect to the case where a conventional composite target as shown in FIG. 1 is used. This conventional composite target 30 includes a Ta piece 31 and M.

The pieces are arranged alternately at a constant composition ratio. and,
When sputtering is performed using this as a target, the area surrounded by the broken line shown in FIG. 2 usually becomes the erosion region 33. In this case, the composition ratio of the target corresponds to the composition ratio of the produced film at the center in the longitudinal direction, but at both ends in the longitudinal direction, the progress line of sputtering draws a curve or an arc. , the erosion region 33 has a non-uniform shape, which causes a disadvantage that the composition of the deposited film to be formed and the compositional acid ratio of the target do not correspond one to one. In the case of the example shown in FIG. 2, the Ta content is higher than the target composition. For this reason, the physical properties of the produced alloy film also become non-uniform at both ends in the longitudinal direction, resulting in a problem of reduced film-forming efficiency and product yield.

The present invention has been made in view of the problems associated with the prior art as described above, and it is possible to prevent the film composition of the deposited film from becoming non-uniform regardless of the shape of the target or the shape of its erosion region. The aim is to provide composite sputtering targets.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above-mentioned object, the sputtering target of the present invention according to the first aspect is provided by dividing a target piece made of a combination of two or more materials into each material. The sputtering target is a sputtering target arranged in a composite manner, and the sputtering target is surrounded by a circle having a diameter equal to the erosion width in the erosion region furthest from the center of gravity of the sputtering target among the regions where erosion is performed in a curved shape. having an irregular erosion area defined as an area where
In at least one of the irregular erosion regions, there is a portion where at least one of the shape or surface area of the target piece is changed, and target pieces made of two or more types of materials are divided for each material and arranged in a composite manner. , at least partially formed.

Furthermore, a sputtering target of the present invention according to a second aspect is a sputtering target formed by dividing target pieces made of a combination of two or more types of materials and arranging them in a composite manner for each material, the sputtering target has an irregular erosion region defined as a region surrounded by a circle whose diameter is the erosion width in the erosion region farthest from the center of gravity of the sputtering target among the regions where erosion occurs in a curved shape, and this Irregular Erotica 1 An alloy target piece made of an alloy containing the constituent metal species of the target piece is disposed in at least a part of the one region.

Hereinafter, the present invention will be described in more detail based on embodiments of the present invention shown in the drawings.

FIG. 3 is a plan view of the sputtering target 1 according to the embodiment of the present invention. In this example, the planar shape of the sputtering target 1 is rectangular as shown in the figure, and this rectangular structure has a longitudinal direction. The rectangular Mo pieces 2 and Ta pieces 3 are arranged alternately except for both ends. In this way, M is arranged at both ends.

The shape or surface area of each target piece of Ta and Ta can be determined so that the composition of the deposited film at both ends is the same as the composition at the center, and the arrangement thereof can be determined as appropriate.

By arranging the target pieces in a combination that changes the shape or surface area of each target piece, the two compositions of the formed film at the edges are adjusted to the optimum state, and the composition ratio of the target and the formed film are adjusted to the optimum state. Since the composition ratio can be kept in a one-to-one correspondence state, the problem of non-uniformity of the film composition at the edge, which conventionally occurred unavoidably due to the mode of erosion, is solved, and the composition and film properties (e.g. It is possible to obtain a deposited film with a uniform resistivity (specific resistance).

The above-mentioned aspects of the present invention will be explained in further detail.

The plan view shown in FIG. 4 shows how the erosion region 33 is formed in the sputtering target 1 having a rectangular planar shape. In the present invention, in such an erosion region 33, a region surrounded by a circle having a diameter equal to the erosion width k in the erosion region farthest from the center of gravity G of the sputtering target among the regions where erosion is performed in a curved shape;
In at least one of the irregular erosion regions E, a target piece made of two or more types of materials is formed by changing at least one of the shape or surface area of the target piece, as described above. The device is characterized in that at least a portion thereof is formed by dividing each material into parts and arranging them in a composite manner.

In a preferred embodiment of the present invention, it is particularly preferable that target pieces are divided and arranged in a range of 2 to 21 pieces within each of the above-mentioned irregular erosion regions. By dividing the target in the irregular erosion region into numbers within this range, the film characteristics over the entire deposited film can be made uniform, and the quality of the film itself is improved.

According to the research of the present inventors, in the deposited film obtained by sputtering a sputtering target, the following formula is used: The maximum resistance error is expressed by rate is 15
By dividing and arranging the target pieces so that the target pieces are less than %, it is possible to obtain a sputtering target that has no practical problems and is advantageous in terms of cost. This point is also shown in the examples described below, but when the number of target pieces in one irregular erosion region is less than 2, the maximum resistance error rate increases rapidly; When the number of particles exceeds 1, the number of boundaries between target pieces increases, and impurities and microparticles generated by so-called reverse sputtering enter these boundary areas, and these are scattered as foreign substances during sputtering, resulting in the formation of a film. This is undesirable because it results in an increase in the proportion of these foreign substances mixed in. Furthermore, an increase in the number of divisions is disadvantageous in terms of manufacturing costs.

In the present invention, when the combination of target pieces consists of a combination of two types of materials, either one of the materials can be used when the total number of target pieces arranged in the irregular erosion area is N. The number of target pieces is preferably (N/2) or (N/2)±1.

In the present invention, even if only one target piece is placed in the irregular erosion region, the center/corner or apex angle of the target piece is set to 45 to 160 degrees, more preferably 60 to 150 degrees. Also by doing
It is possible to reduce the maximum resistance error rate to 15% or less.

This will be described later (Example 1).

FIG. 5A is a plan view showing the state of erosion when sputtering is performed using a sputtering apparatus having a plurality of magnetrons, and FIG. 5B is a plan view showing a longitudinal center line passing through the center of gravity G in FIG. 5A. FIG.

In the present invention, it is possible to obtain good results by satisfying the conditions of the number of target pieces in the irregular erosion region and the maximum resistance error rate in the target applied to such a sputtering apparatus, as described above. I can do it.

Next, specific aspects of the target of the present invention will be further explained.

The example shown in FIG. 3 is an example in which wedge-shaped target pieces are arranged in a fan shape only at both longitudinal ends of a rectangular structure, but the present invention has various other aspects. Conceivable. For example, the example shown in FIG.
Alternatively, shapes composed of straight lines and curved lines as shown in FIGS. 14 and 15 may be combined. Also, as in the example shown in Fig. 7, if the target has a shape other than a rectangle, such as a triangle, a shape similar to a triangle with curved corners, or a shape similar to a fan shape with curved corners. However, as long as the planar shape is such that an irregular erosion region is formed, the present invention can be similarly applied. In the example shown in FIG. 7, Mo target pieces 2 and Ta target pieces 3 are divided and arranged alternately as shown in the figure in a portion corresponding to the irregular erosion area.

The example shown in FIG. 8 is an example in which Mo and Ta target pieces are arranged alternately and in parallel at both extreme ends in the longitudinal direction and have different surface area ratios than the Mo and Ta target pieces placed in the center. It is. In this way, the film formation composition can also be adjusted by appropriately changing only the surface area ratio of the target pieces arranged in the center and both ends.

Furthermore, FIGS. 9 to 11 are modified examples of the present invention, and such embodiments are also included within the scope of the present invention.

Next, M is used to form an alloy film for electrical wiring.

- Taking Ta-based composite sputtering target as an example,
The composition will be explained.

2. Description of the Related Art In recent years, active matrix liquid crystal display devices configured using thin film transistors (TPTs) using amorphous silicon films as switching elements have been attracting attention. This is a TFT using an amorphous silicon film that can be formed at a low temperature using an amorphous glass substrate.
This is because by forming an array, it is possible to realize a panel display (flat type television) with a large area, high precision, high image quality, and low cost. On the other hand, in order to make the display pixels of such an active matrix liquid crystal display device as small as possible and increase the area, it is necessary to make the signal lines to the TFTs, that is, the gate wiring and data wiring, thinner (and longer). For example, when adopting a staggered TPT structure in which the gate electrode wiring is provided on the glass substrate side and an insulating film or amorphous silicon film is layered on this surface to form the TPT, the gate electrode wiring The material is required to be thin, have sufficiently low resistance, and withstand subsequent chemical treatment.

Conventionally, various metal films such as tantalum (Ta) and titanium (Ti) have been used as gate wiring materials that satisfy these conditions, but in order to achieve even larger area and higher precision, it is necessary to It is necessary that the material has low resistance, excellent workability, and excellent resistance to various chemical treatments during the manufacturing process.

As an alloy film that satisfies the above requirements, an alloy film of Ta and Mo as described above is suitable, and the present invention exhibits excellent effects as a sputtering target for this purpose.

9 Specifically, an alloy film suitable for the above uses is such that the composition of the deposited film formed by sputtering is, in atomic percent, MO5 to 70%, Ta30 to 95%, more preferably Mo15 to 50%. %, and Ta is 50 to 85%.

In the above alloy composition, the Ta content is less than 30 at%,
Alternatively, a composition in which the Mo content exceeds 70 atom % is not preferable because the electrical resistance of the alloy film becomes large and the oxide film forming property and chemical cleaning property deteriorate. Also, conversely, Ta
If the Mo content exceeds 95 atomic % or the Mo content is less than 5 atomic %, although the processability and oxide film formation properties of the alloy film itself will improve, the electrical resistance will increase.
It is not suitable for the above uses.

According to the target of the present invention, it is possible to obtain an alloy film with a composition that accurately corresponds to the target composition, so by using a composite target whose area ratio is adjusted to have a composition within the above range, the maximum resistance error rate can be reduced. An alloy film of 15% or less can be produced.

As a result of systematic experiments on various metal and alloy films as electrical wiring materials for semiconductor devices using amorphous silicon films, polycrystalline silicon films, single crystal silicon substrates, etc., the present inventors found that Ta It has been discovered that an alloy film consisting of a limited composition range of MO and MO has a much lower electrical resistance than that of a Ta or Mo film alone.

Furthermore, the alloy film having such a limited composition has excellent properties such as processability, oxide film forming property, and ohmic contact with silicon, which are required for large-area electrical wiring thin films.

As a sputtering target for obtaining the above alloy film, in addition to the above-mentioned binary composite target, the target itself may be made of an alloy.

The second aspect of the present invention will be described below.

A sputtering target of the present invention according to a second aspect is a sputtering target formed by dividing target pieces made of a combination of two or more types of materials and arranging them in a composite manner for each material, wherein the sputtering target is , which has an irregular erosion region defined as a region surrounded by a circle whose diameter is the erosion width in the erosion region farthest from the center of gravity of the sputtering target among the regions where erosion occurs in a curved shape, and this The present invention is characterized in that an alloy target piece made of an alloy containing the constituent metal species of the target piece is disposed in at least a part of the irregular lotion area.

In the example shown in FIG. 12, the planar shape of the sputtering target 1 is rectangular, and this rectangular structure has Mo target pieces and Ta target pieces arranged alternately except for both ends in the longitudinal direction. On the other hand, alloy target pieces 4 made of a Mo-Ta alloy having a predetermined composition ratio are arranged at both ends. The composition of this alloy target piece 4 can be adjusted as appropriate so that the composition at the end portion where the irregular erosion region is formed is the same as the composition of the formed film in the central portion, depending on the desired film composition and the shape of the target. It can be selected as appropriate.

In this way, in the present invention, by arranging the alloy target piece 4 as described above in at least a part of the irregular erosion region, the film composition in the irregular erosion region and the film composition in other regions can be made uniform. It can be done. Therefore, it is possible to solve the conventional problem of non-uniform film composition, and to obtain a high-quality deposited film with uniform composition and film properties (for example, specific resistance).

The example shown in FIG. 12 above is an example in which alloy target pieces are arranged at both longitudinal ends of a rectangular structure.
The present invention is not limited to this embodiment, but for example, as shown in FIG.
It is also possible to arrange the a piece 3 and arrange the alloy target piece 4 in a portion adjacent to this. That is, in the present invention, it is sufficient that the alloy target piece 4 as described above is disposed in at least a portion of the irregular erosion region.

3. Such an alloy target piece can be similarly applied to the composite targets shown in FIGS. 3, 6 to 11 described above.

The alloy target piece as described above can be manufactured by melting each constituent metal by electron beam melting, consumable electrode type arc melting, or the like.

Next, an example in which a composite sputtering target was actually produced and an alloy film was formed using the obtained target will be described.

Example 1 A Ta-Mo based composite target was prepared in which wedge-shaped target pieces were arranged in an irregular erosion region as shown in FIG. The manufacturing conditions are as follows.

First, rectangular Ta target pieces 2 and rectangular Mo target pieces 3, which had been cut and ground, were arranged alternately, and one more Mo target piece was arranged. In this case, Mo and Ta targets, which have a wedge shape at both ends in the longitudinal direction, are arranged alternately symmetrically with respect to two center lines passing through the center of gravity, and a target with a width of 127 mm and a length of 508 was manufactured.

Using targets different in the number of divisions obtained as described above, M
An o-Ta alloy thin film was formed.

The maximum resistance error rate was measured for each of the obtained alloy films. The maximum resistance error rate is expressed by the following formula, where y is the resistance of each point dividing into 20 equal parts the center line passing through the center of gravity G in the longitudinal direction of the deposited film formed in the shape and area corresponding to the sputtering target. It means the average value, and X means the resistance value with the largest difference from the above average value.

Figure 16 shows the results. In this graph, the horizontal axis indicates the number of target pieces existing inward (abnormal erosion region) with a radius of 28 mm centered on a point 30 mm from both ends of the target in the longitudinal direction.

As is clear from Fig. 16, in the irregular erosion region, if wedge-shaped, triangular, square, or pentagonal target pieces are not placed, the maximum resistance error rate is 62%, resulting in large variations in resistance values. However, if at least one target piece having these shapes is arranged, the maximum resistance error rate will be 15% or less, or 10% or less, and the quality will be stable enough for wiring materials, especially gate electrodes of thin film transistors. It was found that an alloy film could be obtained.

In this case, good results were obtained even when the number of target pieces was 1 because the apex angle or center angle of the target piece placed in the irregular erosion area was within the range of 45 to 160 degrees. This is because it has been set. FIG. 18 is a graph showing the relationship between the apex angle or center angle of a target piece (for example, wedge-shaped, trapezoidal, pentagonal, etc.) placed in the irregular erosion region and the maximum resistance error rate. As can be seen from this graph, even when there is only one target piece placed in the irregular erosion area, the apex angle or central angle of the target piece is 45 to 16
By setting it in the range of 0 degrees, the maximum resistance error rate can be made 15% or less.

Example 2 Next, a Ta-Mo based composite target having a target arrangement as shown in FIGS. 8, 9 and 10 was prepared. The manufacturing conditions are as follows.

First, rectangular Ta target pieces 2 and rectangular Mo target pieces 3, which had been cut and ground, were arranged alternately, and one more MO target piece was arranged. In this case, at both ends in the longitudinal direction, each square-shaped target whose surface area is different from that of the target piece in the center is placed at two points passing through the center of gravity.
A target with a width of 127 mm and a length of 508 mm was manufactured by arranging the targets alternately symmetrically with respect to the center line of the book.

For each target obtained as above,
Sputtering was performed using targets with different numbers of divisions to form a Mo-Ta alloy film.

That is, Mo--Ta alloy thin films were formed in an argon atmosphere using the targets with different numbers of divisions obtained as described above, using a DC magnetron sputtering device under output conditions of 6 A and 2 kW.

The maximum resistance error rate was measured for each of the obtained alloy films. The maximum resistance error rate was measured in the same manner as in Example 1.

Figure 17 shows the results. In this graph, the horizontal axis indicates the number of target pieces existing within a circle (irregular erosion region) with a radius of 28+am centered on a point located at a distance of 90+nm from both ends of the target in the longitudinal direction.

As is clear from FIG. 17, when the number of target pieces in the irregular erosion region is less than 2, the maximum resistance error rate increases extremely and large variations in resistance value occur. It can be seen that the maximum resistance error rate becomes 15 to 810% or less when the resistance exceeds 10%, and an alloy film of sufficiently stable quality can be obtained as a wiring material, especially as a gate electrode of a thin film transistor.

〔Effect of the invention〕

As is clear from the results of the above examples, the sputtering target according to the present invention has excellent effects as a target for forming metal thin films used in semiconductor devices and the like. In particular, according to the sputtering target of the present invention, it is possible to obtain a metal thin film with a large area and homogeneous film characteristics.
Moreover, it is suitable for forming wiring thin films useful for low-cost panel displays (flat-type televisions).

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional sputtering target, FIG. 2 is a plan view showing erosion when sputtering the sputtering target shown in FIG. 1, and FIGS. 3, 6 to 11 are , a plan view showing an embodiment of a sputtering target according to the present invention, FIGS. 4 and 5A are explanatory diagrams showing an S-shaped erosion and an irregular erosion region E when sputtering a sputtering target, and FIG. 5B is a plan view showing an embodiment of a sputtering target according to the invention. is a sectional view taken along VA-VA in FIG. 5A, FIGS. 12 and 13 are plan views showing an embodiment of the sputtering target of the present invention in which alloy target pieces are arranged in the irregular erosion region, and FIG. 15 is a plan view showing the shape of the target pieces, FIGS. 16 and 17 are graphs showing the relationship between the number of target pieces and the maximum resistance error rate in the irregular erosion region, and FIG. 18 is a plan view showing the shape of the target pieces. 3 is a graph showing the relationship between the apex angle of a wedge (wedge shape) and the maximum resistance error rate. 2... Molybdenum target piece, 3... Tantalum target piece, 33... Erosion area, 4... Alloy target piece.

Claims (20)

[Claims] 1. A sputtering target formed by dividing target pieces made of a combination of two or more types of materials and arranging them in a composite manner for each material, wherein the sputtering target is arranged within a region where erosion is performed in a curved shape. , has an irregular erosion region defined as a region surrounded by a circle having a diameter equal to the erosion width in the erosion region farthest from the center of gravity of the sputtering target, and at least one of the irregular erosion regions has the target piece. A sputtering target at least partially formed by dividing target pieces made of two or more types of materials by changing at least one of the shape or surface area and arranging them in a composite manner. 2. The maximum resistance error rate of the deposited film obtained by sputtering a sputtering target is expressed by the following formula:
The sputtering target according to claim 1, wherein the sputtering target is 15% or less. Maximum resistance error rate (%) = (|■ - X means the average value of the resistance values at each point, and X means the resistance value that has the largest difference from the above average value ■. 3. The sputtering target according to claim 1, wherein the target pieces are divided into 2 to 21 pieces and arranged in the irregular erosion region. 4. At least a portion of the irregular erosion region has at least one shape selected from the following: a wedge shape, a triangle or a pentagon, or a shape formed by one curve and one straight line, one curve and two straight lines, or two curves and two straight lines. The sputtering target according to claim 1, wherein the target pieces are divided into 2 to 16 pieces and arranged. 5. The sputtering target according to claim 1, wherein at least one target piece having a shape having a center angle or an apex angle of 45 to 160 degrees is arranged in at least one of the irregular erosion regions. 6. The sputtering target according to claim 3, wherein a plurality of said irregular erosion regions exist. 7. The erosion of the sputtering target is
4. The sputtering target according to claim 3, wherein the sputtering target is carried out using a sputtering apparatus having one magnetron. 8. The erosion of the sputtering target is
The sputtering target according to claim 3, which is performed using a sputtering apparatus having a plurality of magnetrons. 9. Each target piece is made of a single type of material, the combination of target pieces is made of a combination of two types of materials, and the total number of target pieces arranged in at least one irregular erosion region is N. In this case, the number of target pieces of either material is
The sputtering target according to claim 3, wherein the number of sputtering targets is from (N/2)-1 to (N/2)+1. 10. 4. The sputtering target according to claim 3, wherein each target piece is formed of a single type of material, and the combination of target pieces consists of a combination of three types of materials. 11. 2. The sputtering target according to claim 1, wherein the target pieces are alternately and symmetrically arranged for different materials with respect to the center line of the target. 12. The shape of the target pieces arranged in the at least one irregular erosion region is selected from a wedge shape, a trapezoid, a quadrangle, a pentagon, a shape formed by one curved line and two straight lines, or a shape formed by two curved lines and two straight lines. The sputtering target according to claim 1, comprising: 13. The sputtering target according to claim 1, wherein the sputtering target is made of a composite target of molybdenum and tantalum. 14. At least a portion of the irregular erosion area,
Claim 3: Target pieces made of an alloy are arranged.
Sputtering target described in. 15. 13. The area ratio of the target piece is adjusted so that the composition of the deposited film formed by sputtering is 5 to 70% molybdenum, 30 to 95% tantalum, and unavoidable impurities in terms of atomic percent. Sputtering target described in. 16. A sputtering target formed by dividing target pieces made of a combination of two or more materials and arranging them in a composite manner for each material, wherein the sputtering target is arranged in a region where erosion is performed in a curved shape. ,
The sputtering target has an irregular erosion region defined as a region surrounded by a circle having a diameter equal to the erosion width in the erosion region farthest from the center of gravity of the sputtering target, and at least a part of this irregular erosion region is covered with the target piece. A sputtering target in which alloy target pieces made of an alloy containing constituent metal species are arranged. 17. 17. The sputtering target of claim 16, wherein the alloy target piece is comprised of an alloy of molybdenum and tantalum. 18. Claim 1: The composition of the target piece is adjusted so that the composition of the deposited film formed by sputtering consists of 5 to 70% molybdenum, 30 to 95% tantalum, and unavoidable impurities in atomic percent.
6. The sputtering target described in 6. 19. A method of forming a metal thin film on a base material using a sputtering target formed by dividing target pieces made of a combination of two or more materials and arranging them in a composite manner for each material, comprising: The sputtering target has an irregular erosion region defined as a region surrounded by a circle having a diameter equal to the erosion width in the erosion region furthest from the center of gravity of the sputtering target among the regions where erosion occurs in a curved shape. , Within this irregular erosion region, there is at least a partial portion in which at least one of the shape or surface area of the target piece is changed, and target pieces made of two or more materials are divided into each material and arranged in a composite manner. 1. A method for forming a metal thin film, comprising: preparing a sputtering target formed by forming a metal thin film, and forming a deposited film on a base material by sputtering the sputtering target. 20. The method according to claim 18, wherein the maximum resistance error rate expressed by the following formula in the deposited film obtained by sputtering a sputtering target is 15% or less. Maximum resistance error rate (%) = (|■ - X means the average value of the resistance values at each point, and X means the resistance value that has the largest difference from the above average value ■.