CN108431293A - Cylindrical ceramic sputtering target and cylindrical ceramic sputtering target formed by joining one or more cylindrical ceramic sputtering targets on the backing tube - Google Patents

Abstract

The cylinder-shaped ceramic sputtering target being bonded on the object of the present invention is to provide a kind of cylinder-shaped ceramic sputtering target material and by the cylinder-shaped ceramic sputtering target material on backing pipe, thus, it is possible to inhibit electric arc occur, tubercle, cracked problem occur, wherein described problem is only by being provided separately within various mass properties (crystal size, relative density, conductivity etc.) in appropriate range and can not prevent.A kind of cylinder-shaped ceramic sputtering target material is provided, on cylinder-shaped ceramic sputtering target material, it is divided into four parts of regions in the axial direction of target, each of four parts of regions are divided into region with 0 °, 90 °, 180 ° and 270 ° of interval in a circumferential direction again, when measuring aberration Δ E*ab on each region marked off, aberration Δ E*ab is less than 1.0.

Description

Cylindrical ceramic sputtering target and bonding one or more cylindrical ceramic sputtering targets to a backing tube Cylindrical ceramic sputtering target made of porcelain sputtering target

technical field

The present invention relates to a cylindrical ceramic sputtering target and a cylindrical ceramic sputtering target formed by joining one or more cylindrical ceramic sputtering targets to a backing tube. In particular, it relates to a cylindrical sputtering target (hereinafter referred to as "cylindrical sputtering target") of a sintered body of a transparent oxide semiconductor such as IGZO (indium gallium zinc oxide), IZO (indium zinc oxide), and ITO (indium tin oxide). Target".) and a cylindrical sputtering target (hereinafter referred to as "cylindrical target") that is combined with the cylindrical sputtering target on the backing tube.

Background technique

For cylindrical targets, it is preferable to manage various bulk properties (grain size, relative density, electrical conductivity, etc.) within appropriate ranges. However, many test items (grain size, relative density, bulk resistance value, surface roughness, etc.) are partial tests, and each test item is basically obtained independently. Furthermore, when testing the performance of a cylindrical target, it cannot be tested and evaluated along with the destruction of the product itself. Furthermore, when a cylindrical target is used, compared with the conventional flat target, it is difficult to manufacture, and because the composition of the target and the heat conduction method and position of heat conduction in the target during sintering are different. Uniform and uneven oxygen concentration will make it extremely difficult to manufacture a target with uniform characteristics throughout the block.

On the other hand, it is known that if there is only one point of failure on the use surface of a cylindrical target, problems such as arcing, nodules, and cracks will occur. In fact, on cylindrical targets, abnormal conditions such as arcs and nodules often occur during sputtering. Even if the test items (grain size, relative density, bulk resistance value, surface roughness, etc.) of the factors affecting sputtering are tested for targets that appear abnormal during sputtering, the factors that affect sputtering are often There was no abnormality at all, and at this time, the cause of abnormalities such as arcing and nodules during sputtering is unknown. Therefore, there is a problem that when there is no abnormality in each test item regarding each factor affecting sputtering, a problematic cylindrical target or cylindrical target cannot be detected without actually performing sputtering. From this point of view, an index for comprehensive evaluation and management of cylindrical targets is also needed.

The inventors of the present application have recognized the importance of evaluation using the results of macroscopic observations, that is, comprehensive observations, as a result of earnest research. Conventionally, when producing a sintered body, by changing the sintering conditions, the relative density and crystal grains can be controlled, and the characteristics during sputtering can be improved. However, since the evaluation of grains usually uses the index of the average grain size (measured by referring to the SEM photograph taken with the observation field of several hundred to several thousand times by the coding method, etc.), it still stays at the standard of the cylindrical target. local evaluation.

However, it is known that the crystal grain distribution of a cylindrical target can be roughly classified into the following four patterns. The first mode is the case where the distribution is gradually from small grains to large grains, the second is the case where there are, for example, large grains with abnormal grain growth among the small grains, the third mode is the case where the grain diameters are polarized, and No. The four modes are the cases where all grains are uniform.

Among the above four modes, the main problem is that when the first mode to the third mode are viewed macroscopically, there are modes in which the sizes of crystal grain groups differ from group to group. When there is a mode in which the grain size differs between groups of crystal grains (that is, it is not a difference between individual crystal grains when viewed macroscopically, but a collection area of crystal grains that are uniform to a certain extent is obtained as a group, there are multiple Groups, each of which is composed of grains of different sizes.), cracks often occur at the interface between the groups. Furthermore, as a result, the strength of each region in the cylindrical target varies depending on the grain size, and the problem that the surface roughness changes when the surface is cut occurs. Therefore, it is important to comprehensively evaluate and manage the characteristics of the cylindrical target as a whole.

In Patent Document 1, it is described that the average particle size of the compound contained in the oxide semiconductor sputtering target is set to be 10 μm or less, preferably 6 μm or less, more preferably 4 μm or less; Part and the color difference ΔE of the part that is ground 2 mm from the surface part with a surface grinder is controlled below a predetermined value, and the resistivity is set below a predetermined value, thereby when forming an oxide thin film such as an oxide semiconductor or a transparent conductive film, it is obtained. A sputtering target that does not require an increase in oxygen partial pressure, does not easily form aggregates, and suppresses occurrence of abnormal discharge. However, according to the experimental results described in Patent Document 1, it is confirmed that the resistivity is set below a predetermined value only by the relationship with the crystal grain size, basically without any relation to the control of chromatic aberration.

Patent Document 2 discloses a target in which the stoichiometric deviation of the composition of the sputtering target is controlled by controlling the color of the target, thereby significantly suppressing the generation of particles during sputtering. However, it is the color itself as a problem, not the color difference ΔE*ab. In addition, this fabrication method is a conventional method of fabricating flat targets and does not involve cylindrical targets. In Patent Document 3, the uneven color of the sputtering target will cause uneven heat radiation from the target surface during sputtering heat generation, and problems such as temperature differences will easily occur. Therefore, in order to suppress the uneven color, it is proposed to contain Zr, Si Zinc oxide sintered body with at least one additive in Al. However, the sputtering target described in Patent Document 3 is a conventional flat-plate target, and since color unevenness is prevented by containing additives in the target, the composition of the target is different from the composition of the thin film to be formed by sputtering. , so it's not a fundamental solution. In Patent Document 4, the color difference (color unevenness) is a color difference between the surface and the inside of the sintered body as a problem, so it is only a local evaluation of the target. In addition, it relates to a conventional flat-plate target, and the specific method for solving the color difference between the surface and the interior is the same as in Patent Document 3, which contains additives from Al, Ga, B, Nb, In, Y, Method of at least one element chosen in Sc. Therefore, the invention described in Patent Document 4 is also the same as Patent Document 3. In this invention, even if the color difference between the surface and the inside of the target can be eliminated, due to the composition of the target and the composition of the thin film formed by sputtering, different, therefore, its not a fundamental solution.

prior art literature

patent documents

Patent Document 1: WO2012-153522 Publication

Patent Document 2: Japanese Patent Laid-Open No. 2001-11614

Patent Document 3: Japanese Patent Laid-Open No. 2010-202896

Patent Document 4: Japanese Patent Laid-Open No. 2010-150107

Contents of the invention

The technical problem to be solved by the invention

The object of the present invention is to provide a cylindrical target that can suppress the problems of arcing, nodules, and cracks by combining various bulk properties (grain size, relative density, bulk Resistance value, surface roughness, etc.) are locally individually set within an appropriate range, that is, basically independent acquisition of multiple parameters for evaluation cannot be prevented. Specifically, a cylindrical target material and a cylindrical target material are provided, which not only take into account the observation results of individual factors affecting sputtering with respect to the characteristics of the cylindrical target material, but also take into account As a result of macroscopic observation of the entire target material, uniformity of the entire target material can be ensured. The cylindrical target is a cylindrical target in which one or more of these cylindrical target materials are bonded to the backing tube.

means of solving problems

In order to solve the above-mentioned problems, the inventors of the present application focused on the color difference ΔE*ab of the cylindrical target. That is, a cylindrical target, even if the various test items (grain size, relative density, bulk resistance value, surface roughness, etc.) related to the factors affecting sputtering are tested, there is no abnormality in the factors affecting sputtering , but during actual sputtering, abnormalities such as arcs and nodules may occur. The cylindrical targets are all targets in which the color difference ΔE*ab on the surface of the cylindrical target varies with the region. On the other hand, when the cylindrical target has almost the same color difference ΔE*ab as viewed visually on the entire surface, abnormalities such as arcing and nodules tend to occur during sputtering rarely occur. As a result of earnest research, the present inventors have found that the color difference ΔE*ab is effective as an index for evaluating and managing the entire sintered body. It is known that the color difference ΔE*ab can be regarded as a comprehensive result of the bulk characteristics of each cylindrical target material, and making the color difference ΔE*ab as uniform as possible in the sintered body will suppress abnormalities in sputtering. In this way, they discovered the color difference ΔE*ab as an index for stabilizing the overall characteristics of the cylindrical target, and completed the invention.

In this specification, the color difference ΔE*ab is measured using NF333 manufactured by Nippon Denshoku Kogyo Co., Ltd. The color difference can be represented by Equation 1 below.

ΔE*ab=((ΔL*)^2+(Δa*)^2+(Δb*)^2)^0.5 (Formula 1)

Crystal grains are representative of the structure of cylindrical targets and have a great influence on electrical conductivity and the like. The color difference ΔE*ab is affected by the target structure or physical shape such as relative density, grain size, surface roughness, etc. The present invention aims at the color difference Δ* affected by the target structure or physical shape such as relative density, grain size, surface roughness, and can provide uniform sputtering of the entire block by knowing the overall color difference Δ* of the cylindrical target. target.

According to the present invention, a cylindrical target material is provided, which is characterized in that: it is divided into four parts at equal intervals in the axial direction, and then each of the four parts is divided into 0°, 90°, 180° and The interval of 270° is divided into 16 areas, and each area is used as a measurement area. At this time, the color difference ΔE*ab at two predetermined points in each measurement area is 1 or less. In addition, a cylindrical target is provided, that is, one or more sputtering targets are prepared, and the sputtering target is bonded to a backing tube made of Ti, Cu, or an alloy containing these metals. The characteristic of the target is that it is divided into four parts at equal intervals in the axial direction, and then each of the four parts is divided into 16 regions at intervals of 0°, 90°, 180° and 270° in the circumferential direction. Each of the above 16 areas is used as a measurement area, and at this time, the color difference ΔE*ab at two predetermined points in each measurement area is below 1.

The relative density of the cylindrical target according to the present invention is preferably above 99%.

Invention effect

With the present invention, it is possible to provide a cylindrical target material and a cylindrical target bonded to a backing tube which ensure that both the individual Observation results of factors affecting sputtering, the uniformization of the target as a result of comprehensively observing the overall target in consideration of the macro, not only the various bulk properties (grain size, relative density, bulk resistance value, surface Roughness, etc.) are set within appropriate ranges, and the occurrence of arcs, nodules, and cracks that could not be prevented in the past can also be suppressed.

Furthermore, according to the present invention, a particularly advantageous effect can be obtained when a cylindrical sputtering target of arbitrary length is formed by joining a plurality of cylindrical targets to the backing tube. That is, when a plurality of targets are bonded to the backing tube, there is a problem that even if only one target with an arc is included in the bonded cylindrical targets, other cylindrical targets that have no problem will be wasted. Lose. According to the present invention, problematic cylindrical targets that cannot be seen through local and individual analysis can be removed and then bonded to the backing tube, preventing the waste of other good cylindrical targets.

Description of drawings

FIG. 1 is a graph showing areas where the grain size, color difference ΔE*ab, and surface roughness of a cylindrical target are measured.

FIG. 2 is a graph showing areas where the grain size, color difference ΔE*ab, and surface roughness of a cylindrical target are measured.

Fig. 3 is a diagram showing the measured crystal grain size, color difference ΔE*ab, and surface roughness area of a cylindrical target as an expanded view of the target material.

Detailed ways

The cylindrical target material and its manufacturing method according to the present invention will be described below with reference to the drawings. However, the cylindrical target material and its manufacturing method of the present invention can be implemented in various forms, and should not be construed as being limited to the contents described in the embodiments shown below. In addition, in the drawings referred to in this embodiment, the same reference numerals are assigned to the same parts or parts having the same functions, and overlapping descriptions will be omitted.

The cylindrical target material of the present invention can be produced by processes such as mixing, crushing, and sintering of various raw material powders. For example, the case of an IGZO sputtering target will be described as an example. Indium oxide (In ₂ O ₃ ) powder, gallium oxide (Ga ₂ O ₃ ) powder, zinc oxide (ZnO) powder, and tin oxide (SnO ₂ ) powder were prepared as raw material powders.

The raw material powders are weighed and mixed in the desired proportion of ingredients. If the mixing is insufficient, the components in the produced target will segregate, and there will be high resistivity regions and low resistivity regions. Therefore, thorough mixing is required. For example, use a super mixer with a rotation speed of 2000-4000 rpm and a rotation time of 3-5 minutes for mixing. Alternatively, a method such as mixing with a ball mill for a long time is also good, and other methods are not particularly limited as long as they can achieve uniform mixing of the raw materials.

Then, the mixed powder is calcined by heating the mixed powder to a temperature range of 900 to 1100° C. in an electric furnace in an air atmosphere and maintaining it for about 4 to 6 hours. However, depending on the optimization of target manufacturing process conditions including sintering conditions, pre-firing is not always necessary or may not be required. If pre-fired, fine-grinded. If finish grinding is not performed sufficiently, raw material powder with a large particle size will exist, and composition unevenness will arise in the surface of a sputtering target. The pre-calcined powder is put into an ultrafine pulverizer, and the fine grinding is carried out at a rotation speed of 200-400 rpm and a selected time of 2-4 hours.

Then granulate. This is to improve the fluidity of the raw material powder, so that the filling condition during stamping is good enough. The water content is adjusted so that the finely ground raw material is a slurry with a solid content of 40-60%, and then granulated.

Then, the granulated powder is shaped using a hydrostatic device (CIP) under the condition of maintaining a surface pressure of, for example, 1700 to 1900 kGf/cm ² for 1 to 3 minutes.

A sintered body can be obtained by heating the molded cylindrical target to, for example, 1400 to 1500° C. using an electric furnace in an oxygen atmosphere, and then maintaining it for 10 to 30 hours.

Generally, in order to increase the relative density, it is preferable to carry out sintering at a high temperature for a long time as much as possible, but in order to control the value of crystal grains, it is necessary to avoid unnecessary high temperature and long time sintering. The grain size and relative density can be controlled to desired values according to the sintering temperature and sintering time.

Finally, surface grinding of the sintered body is performed. Grinding ensures the flatness of the surface.

One or more cylindrical targets whose surface flatness is ensured by grinding are bonded to the backing tube via In or an adhesive material containing In to form a cylindrical target. In addition, the material of the backing tube is not particularly limited. The metal used for the backing tube is usually Ti, Cu or an alloy containing Ti and/or Cu.

In order to clarify the relationship between grain size, surface roughness, and color difference ΔE*ab, the above-mentioned cylindrical target manufacturing method represented by the IGZO target was used, and the sintering time or sintering temperature conditions were changed to manufacture multiple cylindrical IZO targets. Material, cylindrical ITO target and cylindrical IGZO target, measure grain size, surface roughness and color difference ΔE*ab relative density, and use it as a sample for discharge test.

In addition, as a method for producing a target in which the color difference ΔE*ab does not change over the entire surface of the cylindrical target, it is preferable that the particle size of the raw material powder is 30-60 μm, and the tap density is 1.8 g/cm ³ or more. Furthermore, for example, sintering is performed after machining so that the thickness variation of the CIP compact is 0.1 mm or less.

Therefore, for the cylindrical targets according to the embodiments of the present invention, all of them are machined and then sintered so that the thickness variation of the CIP molded body is less than 0.1 mm. The shape of the target was unified to an outer diameter of 153 mmφ, an inner diameter of 135 mmφ, and a length of 210 mm in Examples and Comparative Examples.

The measurement positions of the grain size, surface roughness, and color difference ΔE*ab are as follows. As shown in Figure 1, Figure 2 and Figure 3 (expanded view of the target), the target is divided into four parts at equal intervals in the axial direction of the target, and then each of the four parts is divided into 0°, 90°, 180° ° and 270°, so as to divide 16 regions, and use each region in the 16 regions as a measurement region. A specific measurement position in each measurement area is set at the center (intersection point of diagonal lines) of each measurement area. However, in each measurement area, the point (two points, P1 and P2 in Figure 2) that divides a diagonal line into three equal parts is used as the measurement point in each measurement area, and the color difference ΔE*ab of these two points is used as Color difference ΔE*ab. The reason why the chromatic aberration ΔE*ab of the surface of the target is not measured completely like this is that when the target is observed macroscopically, the chromatic aberration ΔE*ab of the cylindrical target is sometimes in the region of both ends in the axial direction of the target and therebetween. There is a large difference in the area between them, and the purpose of the present invention is to comprehensively evaluate the target as a whole. In addition, the color difference ΔE*ab may vary greatly in the circumferential direction of the cylindrical target.

One of the causes of this is, for example, the distribution of crystals, where groups of different crystal grain sizes are formed. This is because the cylindrical target is different from the flat target. During sintering, the cylindrical target is sintered in a state perpendicular to the axial direction, so the heat transfer method depends on the axial direction of the cylindrical target. vary by region. Another reason is that, for example, the thickness of the CIP compact of the cylindrical target before sintering is different from that of the cylindrical target.

Therefore, the above-mentioned measurement areas for grain size, surface roughness, and color difference ΔE*ab are specified as divisions of areas where the thickness of the CIP molded body of the cylindrical target is likely to vary due to the difference in the heat transfer method during sintering. . In addition, when the axial length of the cylindrical target exceeds 210 mm, it is preferable to additionally perform the same measurement every 50 mm.

The grain size was measured by the following method. First, a sample for observation is cut out from the target, and the surface of the cut sample is mirror-polished. A photograph of the surface texture of the surface of the mirror-polished sample was taken with a scanning electron microscope (SEM), and the grain size of multiple fields of view (5 points) was measured by an evaluation method of the coding method.

The relative density was measured by cutting out a 20 cm ² measurement sample from a cylindrical target, and measuring the density of the cut measurement sample by the Archimedes method. In addition, the relative density referred to in this specification is calculated by (actual density/theoretical density)×100(%). Here, the so-called "actual density" can calculate weight/volume from each measured value, but the Archimedes method is usually used, and the present invention also adopts the same method. The theoretical density is a density value calculated from the theoretical density of oxides of elements other than oxygen among the constituent elements of the sintered body. For example, in the case of an ITO target, indium oxide (In 2 O 3 ) and tin oxide (SnO 2 ) are used as indium oxide (In ₂ O ₃ ) and tin oxide (SnO ₂ ) to calculate the theoretical density. Here, the mass ratio of indium oxide (In ₂ O ₃ ) to tin oxide (SnO ₂ ) is converted from the elemental analysis values (atomic % or mass %) of indium and tin in the sintered body. For example, when the converted result is 90% by mass of indium oxide and 10% by mass of tin oxide in the ITO target, the theoretical density is calculated as (density of In ₂ O ₃ (g/cm ³ )×90+density of SnO ₂ (g /cm ³ )×10)/100 (g/cm ³ ). The theoretical density of In ₂ O ₃ is 7.18 g/cm ³ , and the theoretical density of SnO ₂ is 6.95 g/cm ³ , and the calculated theoretical density is 7.157 (g/cm ³ ). In addition, the oxide ZnO can be calculated when each constituent element is Zn, and the oxide Ga ₂ O ₃ can be calculated when it is Ga. The calculation is performed on the assumption that the theoretical density of ZnO is 5.67 g/cm ³ and that of Ga ₂ O ₃ is 5.95 g/cm ³ .

Conductivity (surface bulk resistance) measurements were performed using a four-probe resistance meter. The surface roughness (arithmetic mean roughness, Ra) is measured using a stylus measuring device, and the values measured within the range of 1 mm or less are compared at multiple points, and the typical value is used as the surface roughness (Ra) value. The arithmetic mean roughness is a value based on JISB0601-2001, and the measuring device includes, for example, SJ-210 (manufactured by Mitutoyo).

The discharge test was performed under the following conditions: Ar was used as the sputtering gas, the sputtering pressure was 0.6 Pa, the flow rate of the sputtering gas was 300 sccm, and the sputtering power was 4.0 W/cm ² .

The cylindrical target made of ITO in Example 1 is divided into four parts at equal intervals in the axial direction, divided into four parts at equal intervals in the axial direction of the target, and then each of the four parts is divided into four parts at 0° in the circumferential direction , 90°, 180° and 270° intervals, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and volume measured in each of the 16 regions The measurement results of resistance are shown in Table 1 below. In addition, in the table below, the four areas respectively shifted by 90° in the circumferential direction are denoted as A, B, C, and D, respectively.

[Table 1]

The cylindrical target made of ITO in Example 2 is divided into four parts at equal intervals in the axial direction, and divided into four parts at equal intervals in the axial direction of the target. , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and mass measured in each of the 16 regions The measurement results of bulk resistance are shown in Table 2 below.

[Table 2]

The cylindrical target made of ITO in Comparative Example 1 is divided into four parts at equal intervals in the axial direction, divided into four parts at equal intervals in the axial direction of the target, and then each of the four parts is divided into four parts at 0° in the circumferential direction , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance in each of the 16 regions The measurement results are shown in Table 3 below.

[table 3]

The cylindrical target made of IGZO in Example 3 is divided into four parts at equal intervals in the axial direction, divided into four parts at equal intervals in the axial direction of the target, and then each of the four parts is divided into four parts at 0° in the circumferential direction , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance in each of the 16 regions The measurement results are shown in Table 4 below.

[Table 4]

The cylindrical target made of IGZO in Example 4 is divided into four parts at equal intervals in the axial direction of the target, and divided into four parts at equal intervals in the axial direction of the target, and then each of the four parts is divided into four parts at 0° in the circumferential direction , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance in each of the 16 regions The measurement results are shown in Table 5 below.

[table 5]

The cylindrical target made of IGZO in Comparative Example 2 was divided into four parts at equal intervals in the axial direction, and divided into four parts at equal intervals in the axial direction of the target. , 90°, 180° and 270° interval division, thus divided into 16 regions, in each of the 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance The measurement results are shown in Table 6 below.

[Table 6]

The cylindrical target made of IZO in Example 5 is divided into four parts at equal intervals in the axial direction, and divided into four parts at equal intervals in the axial direction of the target. , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance in each of the 16 regions The measurement results are shown in Table 7 below.

[Table 7]

The cylindrical target made of IZO in Example 6 is divided into four parts at equal intervals in the axial direction, divided into four parts at equal intervals in the axial direction of the target, and then each of the four parts is divided into four parts at 0° in the circumferential direction , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance in each of the 16 regions The measurement results are shown in Table 8 below.

[Table 8]

The cylindrical target made of IZO in Comparative Example 3 was divided into four parts at equal intervals in the axial direction, divided into four parts at equal intervals in the axial direction of the target, and each of the four parts was divided into four parts at 0° in the circumferential direction. , 90°, 180° and 270° interval division, thus divided into 16 regions, the grain size, surface roughness and color difference ΔE*ab, relative density and bulk resistance in each of the 16 regions The measurement results are shown in Table 9 below.

[Table 9]

In Comparative Example 1, nodules were confirmed to appear in the first region and the fourth region in the discharge test. The color difference ΔE*ab of the area C of the first area is 1.097. The color difference ΔE*ab of the area C on the 4th area is 1.162. It is speculated that when the color difference of the target reaches the color difference ΔE*ab in each area exceeding 1.0, nodules will appear. On the other hand, in Examples 1 and 2, the color difference ΔE*ab of adjacent regions was less than 1.0.

In Comparative Example 2, it was confirmed that cracks appeared around the first region and the fourth region in the discharge test. The color difference ΔE*ab of the area D in the first area is 1.364. The color difference ΔE*ab of the D area of the fourth area is 1.528. It is presumed that when the color difference of the target material reaches the color difference ΔE*ab in each region exceeding 1.0, cracks will occur. On the other hand, in Examples 3 and 4, the color difference ΔE*ab of each area was less than 1.0.

In Comparative Example 3, it was confirmed in the discharge test that cracks appeared throughout the cylindrical target. The color difference ΔE*ab of the area D in the first area is 2.150. In addition, the color difference ΔE*ab of the D area of the third area is 1.722. Furthermore, the color difference ΔE*ab of the D area of the fourth area is 3.045. It is presumed that when the color difference of the target material reaches the color difference ΔE*ab in each region exceeding 1.0, cracks will occur. On the other hand, in Examples 5 and 6, the color difference ΔE*ab of each area was less than 1.0.

From the above, it can be said that when the color difference ΔE*ab in each region is less than 1.0, arcs, nodules, etc. will not occur during sputtering. On the other hand, when the color difference ΔE*ab becomes 1.0 or more, arcing or the like occurs. When the color difference ΔE*ab is about 1.0 to 3.0, the visual color difference is basically not obvious, but through experiments, it was found that even if there is such a color difference that cannot be discerned visually, arcing and the like will occur. In addition, from the relationship between the grain size and the color difference Δ*ab, for example, see Table 6, the analysis result of Comparative Example 2, which compares IGZO cylindrical targets, and it can be seen that the relationship between the grain size and the color difference ΔE*ab is associated. However, looking at Comparative Example 3, which is a comparative example of a cylindrical IZO target, it can be seen that although the crystal grain size is the same as that of the Example of a cylindrical IZO target, the value of the color difference ΔE*ab is different, and cracks appear. On the other hand, in the embodiment where the color difference ΔE*ab in each area is controlled to be less than 1.0, it can be seen from the absence of cracks or nodules that as long as the color difference ΔE*ab in each area is controlled to be less than 1.0, the Prevents cracks or nodules from appearing.

The present invention is not limited to the above-described embodiments, and appropriate changes can be made without departing from the gist.

Claims (7)

1. a kind of cylinder-shaped ceramic sputtering target material is axial length in 210mm cylinder-shaped ceramic sputtering target materials below, feature It is：

The cylindrical shape target is axially divided into four parts at equal intervals, then will be divided into four parts of region each in a circumferential direction with 0 °, 90 °, 180 ° and 270 ° of interval is divided into each region, in described each region 2 points of aberration Δ E*ab less than 1.0。

2. a kind of cylinder-shaped ceramic sputtering target material, is the cylinder-shaped ceramic sputtering target material that axial length is more than 210mm, feature exists In：

From one end of the cylinder-shaped ceramic sputtering target material to 210mm, the cylindrical shape target is axially divided at equal intervals At four parts, then the region for being divided into four parts is each divided into 0 °, 90 °, 180 ° and 270 ° of interval in a circumferential direction each Region, in described each region 2 points of aberration Δ E*ab less than 1.0,

Be more than from one end of the cylinder-shaped ceramic sputtering target material 210mm region in, by the cylindrical shape target in axial direction Per 50mm, segmentation is primary, then the region after segmentation is each divided with 0 °, 90 °, 180 ° and 270 ° of interval in a circumferential direction At each region, 2 points of aberration Δ E*ab is less than 1.0 in described each region.

3. cylinder-shaped ceramic sputtering target material according to claim 1 or 2, it is characterised in that：

The relative density measured in the measured zone is 99% or more.

4. cylinder-shaped ceramic sputtering target material according to any one of claims 1 to 3, it is characterised in that：

The average grain size measured in the measured zone is at 10 μm or less.

5. the cylinder-shaped ceramic sputtering target material according to any one of Claims 1 to 4, it is characterised in that：

The surface roughness measured in the measured zone is at 0.5 μm or less.

6. the cylinder-shaped ceramic sputtering target material according to any one of Claims 1 to 5, it is characterised in that：

The cylinder-shaped ceramic sputtering target material is made of ITO, IGZO or IZO.

7. a kind of cylinder-shaped ceramic sputtering target, it is characterised in that：

Cylinder-shaped ceramic sputtering target material described in any one of more than one claim 1~6 is incorporated on backing pipe.