JP7139453B2 - Sputtering target and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sputtering target comprising a cylindrical substrate and a plurality of cylindrical target materials and a method of manufacturing the same, and more particularly to manufacturing a sputtering target that can use a cylindrical substrate warped due to curved deformation as a material. Regarding the method.

In the manufacture of organic EL, liquid crystal displays, touch panels, and other display devices, in sputtering for forming a transparent conductive thin film made of ITO, etc., a flat sputtering target is used, which is formed by bonding a target material onto a flat substrate. The magnetron sputtering used was the mainstream.
BACKGROUND ART In recent years, rotary sputtering has been put into practical use, in which a cylindrical sputtering target, in which a target material is bonded to the outer peripheral surface of a cylindrical substrate, is rotated around its axis for sputtering. According to such rotary sputtering, there is an advantage that high productivity can be obtained because a markedly higher use efficiency can be realized compared to a flat plate type sputtering target.

Glass substrates used in flat panel displays and solar cells are becoming larger, and in order to form thin films on these larger substrates, a long cylindrical sputtering target with a length of 2 m or more is required. there is However, since it is difficult to manufacture a cylindrical target with a length of 2 m or more, a plurality of cylindrical target materials (also referred to as "divided target materials") are placed on the outside of a long cylindrical base material in the axial direction. A plurality of them are arranged side by side.

For example, in Patent Documents 1 and 2, a plurality of target materials are produced by dividing the target material into a plurality of pieces in the axial direction, and the plurality of target materials are arranged side by side in the axial direction on the outer peripheral side of the cylindrical base material. , and bonding them with a bonding material to manufacture the sputtering target.

As described above, when the cylindrical sputtering target is elongated and the cylindrical substrate is elongated, the influence of warpage of the cylindrical substrate cannot be ignored. In particular, many long cylindrical substrates longer than 2 m are warped, and the width of the warp is large. If the warp of the cylindrical base material is large, the thickness of the bonding material becomes uneven, and in areas where the thickness of the bonding material is thin, insufficient cooling causes problems such as the occurrence of cracks during sputtering. .
In recent years, sputtering apparatuses for depositing films on larger 10th-generation glass substrates have come to be used, and the total length of the target has exceeded 3 m. When the total length of the target exceeds 3 m, the problem of warpage as described above is even more pronounced.

Therefore, in Patent Document 2, attention is paid to the eccentricity between the base material and the target material, and in order to suppress this, the warp of the cylindrical base material is confirmed before manufacturing the cylindrical target, and if the warp is large, , a method of correcting the warpage of a cylindrical substrate using a press machine or the like has been proposed.

Further, Patent Document 3 assumes that the cylindrical base material is curved, and arranges each of the plurality of cylindrical target materials according to the bending deformation of the cylindrical base material. That is, by inclining the central axis of each cylindrical target material or offsetting it in the radial direction at any position in the circumferential direction, the inner peripheral surface of the cylindrical target material and the outer peripheral surface of the cylindrical substrate are aligned. It discloses a method to ensure the required joint material thickness between.

JP 2010-100930 A WO2016/067717 JP 2018-159105 A

The invention described in Patent Document 2 proposes measuring the warp of a cylindrical substrate in advance and correcting the warp using a press or the like when the warp is large. However, when the cylindrical base material is heated in advance when the bonding material is filled, or when the cylindrical base material is heated after being filled with a heat-melted bonding material between the cylindrical base material and the target material, the correction is corrected. There was a problem that the warp returns to its original state (also called "warp return").

In addition, the invention described in Patent Document 3 is based on the assumption that a curved cylindrical base material is used. On the other hand, when the axial length of the cylindrical target material exceeds that, it is difficult to secure the required bonding material thickness.
When a plurality of cylindrical target materials are arranged side by side on the outside of a cylindrical substrate to form a cylindrical sputtering target, gaps between the cylindrical target materials cause nodules during sputtering. It is preferable to reduce the number of divisions of the shaped target material as much as possible. Therefore, as described above, as the length of the cylindrical sputtering target increases year by year, the axial length of the cylindrical target material is also increasing year by year, and the cylindrical target material also tends to be longer, and is less than 750 mm. It's getting more and more difficult.

Therefore, the present invention relates to a sputtering target that can use a warped cylindrical base material as a constituent material and a method for manufacturing the same, and even if the axial length of the cylindrical target material is relatively long, , that is, when the bonding material is filled, the cylindrical base material is preheated, or the heat-melted bonding material is filled between the cylindrical base material and the target material, and the cylindrical base material is heated. It is possible to suppress the influence of the warp of the cylindrical base material to be used even if it is used, and as a result, the thickness of the bonding material is uniform, and the step amount between adjacent cylindrical target materials is small, In addition, it is intended to provide a new method for manufacturing a sputtering target and a new sputtering target, which can manufacture a sputtering target in which the axial distance between adjacent cylindrical target materials is uniform.

The present invention provides a method for manufacturing a sputtering target comprising a cylindrical substrate and a cylindrical target material,
Measure the warp width of the cylindrical base material,
The cylindrical base material is warped in the opposite direction to the warped direction,
A plurality of cylindrical target materials are arranged at intervals in the axial direction outside the processed cylindrical base material, and the cylindrical base material and the cylindrical target material are joined with a bonding material. A method for manufacturing a sputtering target is proposed.

The present invention also provides a sputtering target comprising a cylindrical base material and a cylindrical target material, wherein the cylindrical base material and the cylindrical target material are joined with a bonding material,
At least one of the cylindrical target materials has an axial length of 750 mm or more, a difference between the maximum thickness and the minimum thickness of the bonding material is 1.0 mm or less, and the adjacent cylindrical target materials have a thickness difference of 1.0 mm or less. A sputtering target is proposed in which the maximum step amount between outer peripheral surfaces is 0.5 mm or less, and the difference between the maximum and minimum axial distances between adjacent cylindrical target materials is 0.2 mm or less.

In the manufacturing method proposed by the present invention, the cylindrical base material is deformed again by heating after processing, that is, in consideration of the above-mentioned warpage return, it is reversed by a predetermined width in the direction opposite to the originally warped direction. This is a method of processing a cylindrical substrate so as to warp. Therefore, even if the cylindrical target material is relatively long in the axial direction, and even after heating during filling of the bonding material, the effect of warping of the cylindrical base material used can be eliminated. A sputtering target having a uniform thickness, a small step amount between adjacent cylindrical target materials, and a uniform axial distance between adjacent cylindrical target materials can be manufactured.
Therefore, according to the manufacturing method proposed by the present invention, there is provided a sputtering target comprising a cylindrical substrate and a plurality of cylindrical target materials, wherein at least one of the cylindrical target materials has an axial length of The difference between the maximum and minimum thicknesses of the bonding materials is 1.0 mm or less, and the maximum step between the outer peripheral surfaces of adjacent cylindrical target materials is 0.5 mm or less. It is possible to manufacture a sputtering target in which the difference between the maximum and minimum axial distances between adjacent cylindrical target materials is 0.2 mm or less.

With such a sputtering target, since the thickness of the bonding layer is ensured to be uniform, not only is cracking less likely to occur during sputtering, but also the step amount between the outer peripheral surfaces of adjacent cylindrical target materials is reduced. Since the gap is small and the gap is uniform, the probability of occurrence of an abnormality during sputtering can be significantly reduced. Furthermore, since there is little warpage, that is, bending, the target is less likely to shake when it is rotated, and the distance between the cylindrical target and the substrate can be kept constant, making it possible to make the quality of the film formed by sputtering uniform. can.

1 is a perspective view conceptually showing an example of a sputtering target; FIG. FIG. 3 is a perspective view conceptually showing an example of a warped cylindrical substrate. FIG. 4 is a diagram conceptually showing an example of a method for measuring the warp width of a cylindrical substrate; It is a side view which showed notionally an example of the processing method of a cylindrical base material, (A) is the state before processing, (B) is the figure which showed the state after processing. It is the longitudinal cross-sectional view which expanded and showed the principal part of an example of the manufactured sputtering target. FIG. 4 is an enlarged cross-sectional view of a main part for explaining a step amount h between adjacent target materials and an axial distance d; 1 is a longitudinal sectional view showing a sputtering target manufacturing apparatus used in Examples. FIG.

Next, the present invention will be described based on embodiments. However, the present invention is not limited to the embodiments described below.

<This target manufacturing method>
A method for manufacturing a sputtering target according to an example of an embodiment of the present invention (referred to as "this target manufacturing method") is a sputtering target comprising a cylindrical base material 2 and a plurality of cylindrical target materials 3, 3 . . . A manufacturing method of
measuring the warp width or warp direction of the cylindrical substrate 2 (referred to as a “measurement step”);
Processing is performed to warp the cylindrical base material 2 in the direction opposite to the direction in which it was warped (referred to as a “processing step”),
A plurality of cylindrical target materials 3, 3 . . . A method for manufacturing a sputtering target is characterized in that the cylindrical target material 3 is bonded with a bonding material 4 .

(this sputtering target)
As shown in FIG. 1, a sputtering target (“the present sputtering target”) 1 manufactured by the present target manufacturing method comprises a single cylindrical substrate 2, a plurality of cylindrical target materials 3, and a cylindrical substrate 2. It is a sputtering target formed by arranging the target material 2 side by side at intervals in the axial direction of the material 2 and bonding the cylindrical base material 2 and the cylindrical target material 3 with a bonding material 4 (not shown).
Details of the sputtering target 1 will be described later. Here, first, the constituent members will be described.

(Target material)
The target material consists of a plurality of cylindrical target materials 3, 3 . They are arranged at suitable intervals.

Each cylindrical target material 3 should have an inner diameter larger than the outer diameter of the cylindrical substrate 2 .

While the length of the cylindrical target material tends to increase year by year, it has been pointed out that when the length of the cylindrical target material increases, especially when it exceeds 750 mm, the thickness of the bonding material cannot be secured. However, according to this target manufacturing method, such problems can be resolved, and the effects of the present invention can be further enjoyed.
Therefore, at least one of the plurality of cylindrical target materials ₃ , 3, . Above all, it is more preferably 950 mm or more, more preferably 1400 mm or more.

The material of the cylindrical target material 3 is not particularly limited. For example, oxides containing any one or more of Cu, Al, In, Sn, Ti, Ba, Ca, Zn, Mg, Ge, Y, La, Al, Si, Ga, and W can be used.
Examples of the oxide include In--Sn--O, In--Ti--O, In--Ga--Zn--O, In--Zn--Sn--O, In--Ga--Zn--Sn--O, Ga--Zn-- O, In-Zn-O, In-Ga-O, IWO, I-Zn-WO, Zn-O, Sn-Ba-O, Sn-Zn-O, Sn-Ti-O, Sn—Ca—O, Sn—Mg—O, Zn—Mg—O, Zn—Ge—O, Zn—Ca—O, Zn—Sn—Ge—O, Cu ₂ O, CuAlO ₂ , CuGaO ₂ , CuInO ₂ etc. can be mentioned.

(cylindrical substrate)
Ideally, the cylindrical substrate 2 has a straight central axis and a cylindrical outer peripheral surface parallel to the axis. However, as shown in FIG. 2, the newly used cylindrical base material and the recycled cylindrical base material 2 are warped in a curved shape, in other words, in an arch shape, and the outer peripheral surface of the cylindrical base material 2 is bent from the straight axis direction. have deviations.

The material of the cylindrical substrate 2 may be metal such as Ti, SUS, or Cu. However, it is not limited to these.

(bonding material)
The bonding material 4 is supplied in a molten state to the gap between the cylindrical base material 2 and each cylindrical target material 3 arranged at a predetermined position on the outer peripheral side of the cylindrical base material 2 at the time of manufacturing the sputtering target, and fills the gap. After being filled, it hardens and joins the cylindrical base material 2 and the cylindrical target material 3 .

The material of the bonding material 4 is not particularly limited as long as it can be used for bonding this type of target material and base material. For example, low melting point solder such as In metal, In—Sn metal, or In alloy metal obtained by adding a trace metal component to In can be used.
Since the low-melting point solder has a melting point of 150 to 250° C., the bonding material 4 is normally melted by heating to 150 to 300° C. when the bonding material 4 is filled.

<Measurement process>
In the measurement step, the warp width and warp direction of the cylindrical base material 2 used as the constituent material are measured.

A method for measuring the warp width is not particularly limited. For example, the cylindrical base material 2 may be axially rotated to measure the displacement width of the outer peripheral surface, that is, the warp width. The distance between the smooth surface of the plate and the outer peripheral surface 2a of the cylindrical base 2 may be measured along a perpendicular line set up on the surface plate to measure the width of displacement, that is, the width of warpage. Other methods may be used.

The location for measuring the warp width may be one location in the length direction of the cylindrical substrate 2, or may be two or more locations.
Since the cylindrical substrate 2 is often warped in an arch shape, the maximum warp width and the warp direction can be measured by measuring the warp width near the center in the length direction.
However, since it is not always warped in the shape of an arch, it is preferable to measure the warp width at a plurality of locations spaced apart in the longitudinal direction. For example, it is preferable to measure at intervals of 100 mm to 1000 mm, more preferably at intervals of 200 mm or more or 800 mm or less, and more preferably at intervals of 500 mm or less.

An example of a specific measuring method for measuring the width of warp will be described.
As shown in FIG. 3, a cylindrical substrate 2 is installed horizontally and axially rotatably, a dial gauge 5 is applied to the outer peripheral surface 2a of the cylindrical substrate 2, and the cylindrical substrate 2 is rotated once. The reading of the dial gauge 5 is measured. The difference (Hmax-Hmin) between the maximum value Hmax and the minimum value Hmin of the dial gauge 5 can be used as the warp width.

At this time, the means for axially rotating the cylindrical substrate 2 is arbitrary. For example, it is placed between two rotating rollers and rotated, or the vicinity of both ends of a cylindrical substrate is placed in the grooves of a support base having a V-shaped groove, and is rotated by hand or with a roller. Any means is optional.

In the measurement step, the warp width X and the warp direction of the obtained cylindrical base material 2 may be measured as described above. The warp width Y or warp direction of the shaped substrate 2 may be measured as described above.

When the cylindrical base material 2 is heated and the warp width Y and the warp direction of the cylindrical base material after heating are measured, the heating temperature of the cylindrical base material 2 is the same as that of the cylindrical base material 2 when the bonding material is filled. The temperature at which the cylindrical base material 2 is heated when the heat-melted bonding material 4 is filled between it and the cylindrical target material 3, or the temperature at which the cylindrical base material 2 is heated by the filled bonding material 4 It is preferable to assume However, if the temperature is too high, the surface of the cylindrical substrate 2 may be oxidized. From this point of view, regarding the heating temperature of the cylindrical substrate 2 at this time, it is preferable to heat the surface temperature to 150 to 300° C., especially 160° C. or higher or 240° C. or lower, especially 170° C. or higher. Alternatively, it is more preferable to heat to 230° C. or lower.
A heating method for the cylindrical base material 2 is not particularly limited. For example, the substrate may be placed in an electric furnace or the like and heated from the outside, or a heater may be installed inside the substrate and heated from the inside.

<Processing process>
In the processing step, the cylindrical base material 2 is processed so as to be warped by a predetermined width α in the direction opposite to the originally warped direction.

For example, as shown in FIG. 4, at the measurement position in the measurement process, pressure is applied in a direction opposite to the warp direction measured in the measurement process to bend the cylindrical base material 2, and the result is shown in FIG. 4(B). Thus, the cylindrical substrate 2 may be processed so as to be warped by a width α in the direction opposite to the warped direction, in other words, to be displaced by α from the linear axis.

As for the position to be pressed, for example, when the cylindrical base material 2 is warped in an arch shape, it is possible to deform it by applying pressure to one central portion in the axial direction. Also, it is preferable to pressurize the position measured in the measuring step. For example, it is preferable to measure at intervals of 100 mm to 1000 mm and pressurize at each measuring point to deform.

The width α (mm) by which the cylindrical substrate 2 is warped in the direction opposite to the warped direction is preferably determined based on the warp width X or Y measured in the measurement step. This is because the greater the warp width X or Y, the greater the magnitude of the warp return due to heating after processing.

For example, in the measurement step, when the warp width X is obtained by measuring the warp width of the obtained cylindrical base material 2 as it is, the warp width α (mm) is X (mm) × (0.10 to 2 .00), among which X (mm) × 0.50 or more or X (mm) × 1.50 or less, among which X (mm) × 0.80 or more or X (mm) × 1.40 In the following, X (mm)×0.90 or more or X (mm)×1.30 or less is more preferable.

Further, in the measurement step, when the obtained cylindrical base material 2 is heated and the warped width of the cylindrical base material 2 after heating is measured to obtain the warped width, the warped width α (mm) is (mm) × (0.50 to 1.50), preferably Y (mm) × 0.80 or more or Y (mm) × 1.40 or less, among which Y (mm) × 0.90 Y (mm) x 1.30 or less, more preferably Y (mm) x 0.95 or more or Y (mm) x 1.25 or less.
By actually heating and measuring the warp width Y after heating and determining the warp width α based on the warp width Y, the width α is determined after considering the heating behavior of the obtained cylindrical base material 2 . Therefore, it is possible to further reduce warping and returning.

As a processing method for pressurizing and warping the cylindrical base material 2, for example, as shown in FIG. A method of pressurizing the cylindrical substrate 2 can be mentioned. In addition, P in FIG. 4(A) indicates the pressurizing direction. At this time, as means for pressurizing, for example, mechanical pressing, forging, and the like can be mentioned.
However, any means can be adopted as long as it can warp the cylindrical substrate 2 by a desired width.
At this time, in order to prevent the roundness of the cylindrical base material from changing, it is possible to use an arc-shaped terminal that matches the shape of the cylindrical base material 2 for applying pressure.
Further, heat treatment (annealing) may be performed as necessary.

The processing method of pressurizing and warping the cylindrical substrate 2 may be repeated. That is, the cylindrical base material 2 may be warped by applying pressure, and then warped by applying pressure, and so on, and the process of warping by applying pressure may be repeated to finally warp the cylindrical base material 2 by a predetermined width α.
In addition, the cylindrical substrate 2 is heated (measured for the warp width Y), pressurized to warp, further heated and pressurized to warp, and so on. The cylindrical substrate 2 may be warped by the width α. In this case, the measurement of the warp width Y after heating may be performed only at the beginning.

<Arrangement of Cylindrical Target Materials>
Using the cylindrical base material 2 processed as described above, a plurality of cylindrical target materials 3, 3, . . . do.

The cylindrical target materials 3 are preferably arranged side by side with an interval of 0.15 mm to 0.50 mm in the axial direction.

<Joining>
After the cylindrical target material 3 is arranged as described above, the cylindrical base material 2 and the cylindrical target material 3 are heated to fill the gap between the cylindrical base material 2 and the cylindrical target material 3 with the molten bonding material. 4 is filled, the bonding material 4 is cooled, and each cylindrical target material 3 is bonded around the cylindrical substrate 2 by the bonding material 4 .
The temperature at which the cylindrical base material 2 and the cylindrical target material 3 are heated before filling the bonding material 4 is preferably the temperature of the bonding material 4 or higher.
The temperature of the bonding material 4 when filling the bonding material 4 is a temperature equal to or higher than the melting point of the bonding material, and is preferably 150 to 300° C., especially 160° C. or higher or 240° C. or lower. It is more preferable to heat to 170° C. or higher or 230° C. or lower.
A known method can be adopted as a method of filling and cooling the bonding material.

<This sputtering target>
According to this target manufacturing method, it is possible to eliminate the influence of the warp of the cylindrical base material 2 even after heating at the time of filling the bonding material, so it is possible to manufacture the following sputtering target.

A preferred example of the present sputtering target is a sputtering target comprising a cylindrical substrate 2 and a plurality of cylindrical target materials 3, 3 . , at least one of which has an axial length L3 of 750 mm or more _, a difference between the maximum thickness and the minimum thickness of the bonding material 4 of 1.0 mm or less, and the adjacent cylindrical target materials 3, 3 The maximum value of the step amount h between the outer peripheral surfaces 3a, 3a is 0.5 mm or less, and the difference between the maximum value and the minimum value of the axial distance d between the adjacent cylindrical target materials 3, 3 is 0.2 mm or less. Certain sputtering targets can be mentioned.

The length of the cylindrical base material 2 is preferably 2.0 m to 4 m, more preferably 3.0 m or more or 3.8 m or less, especially 3.3 m, from the viewpoint of being able to enjoy the effects of the present invention more. More preferably, it is 3.7 m or more or 3.7 m or less.
The outer diameter of the cylindrical substrate 2 is preferably 125 mm to 140 mm, more preferably 130 mm or more or 135 mm or less, and more preferably 132 mm or more or 134 mm or less.
The inner diameter of the cylindrical target material 3 is preferably 127 mm to 142 mm, more preferably 132 mm or more or 137 mm or less, and more preferably 134 mm or more or 136 mm or less.
The thickness of the cylindrical target material 3 is preferably 5 mm to 20 mm, more preferably 6 mm or more or 16 mm or less, and more preferably 8 mm or more or 13 mm or less.
The axial length L ₃ of at least one of the cylindrical target materials 3 is preferably 750 mm to 1500 mm, especially 850 mm or more or 1450 mm or less, especially 950 mm or more or It is more preferably 1450 mm or less.

If the difference between the maximum value and the minimum value of the thickness of the bonding material 4 is 1.0 mm or less, the thickness of the bonding material 4 is ensured to be uniform. It is possible to prevent the target from cracking, etc., and suppress the occurrence of cracks during sputtering.
From this point of view, the difference between the maximum thickness and the minimum thickness of the bonding material 4 is more preferably 0.5 mm or less, more preferably 0.3 mm or less.
At this time, the thickness of the bonding material 4 is preferably 0.5 mm or more, more preferably 0.7 mm or more, and more preferably 1 mm or more.
The thickness of the bonding material 4 can be measured by an ultrasonic flaw detector.

The maximum value of the step amount h between the outer peripheral surfaces 3a, 3a of the adjacent cylindrical target materials 3, 3, that is, in the pair of cylindrical target materials 3, 3 adjacent in the axial direction, the respective outer peripheral surfaces 3a, 3a If the maximum value of the step amount h between the outer edges in the axial direction adjacent to each other is 0.5 mm or less, abnormal occurrences during sputtering, specifically arcing, chipping and cracking associated therewith. The probability of occurrence can be reduced. Conversely, if the maximum value of the step amount h is larger than 0.5 mm, the cylindrical target material 3 on one side protrudes, and adverse effects such as abnormal discharge may occur at the protruding edge.
From this point of view, the maximum value of the step amount h is more preferably 0.3 mm or less, more preferably 0.2 mm or less.
The step amount h can be measured using, for example, a depth gauge.

Furthermore, if the difference between the maximum value and the minimum value of the axial distance (interval) d between adjacent cylindrical target materials 3, 3 is 0.2 mm or less, an abnormality occurs during sputtering, for example, thermal expansion during sputtering causes edge It is possible to further reduce the probability of chipping or cracking due to contact between the parts. For example, in a portion where the distance d in the axial direction is large, the cylindrical substrate 2 may be exposed, and components of the substrate may be sputtered and mixed into the film as impurities. On the other hand, in the portion where the distance d in the axial direction is small, there is a possibility that the adjacent cylindrical target materials 3, 3 will hit each other when thermally expanded due to the heat of sputtering, and the cylindrical target material 3 will crack.
From this point of view, the difference between the maximum value and the minimum value of the axial distance d between adjacent cylindrical target materials 3, 3 is more preferably 0.15 mm or less, more preferably 0.1 mm or less.
The axial distance (interval) d can be measured using, for example, a feeler gauge.

<Explanation of terms>
In this specification, when expressing "A to B" (the A and B are arbitrary numbers), unless otherwise specified, with the meaning of "A or more and B or less", "preferably larger than A" or "preferably It also includes the meaning of "smaller than B".
In addition, when expressing "A or more" (A is an arbitrary number) or "B or less" (B is an arbitrary number), it is also possible to express "preferably larger than A" or "preferably less than B". It also includes intent.

The following examples further illustrate the invention. However, the following examples are not intended to limit the present invention.

<Example 1>
A recycled cylindrical base material (length 3400 mm, diameter 133 mm, thickness 4 mm) is placed on a pedestal that can be axially rotatably supported, and placed horizontally and axially rotatably, and the cylindrical base material A dial gauge suspended and fixed from above is applied to the outer surface of the central part in the length direction, and the reading of the dial gauge is measured by rotating the cylindrical base material once, and the maximum value Hmax and the minimum value Hmin of the reading and the difference (Hmax-Hmin) was measured as the warp width X (initial).

Next, the cylindrical base material was placed in an electric furnace and heated so that the surface temperature was maintained at 230° C. for one hour, and the warp width Y after heating (after heating) was measured in the same manner as described above.

Next, press the central portion of the cylindrical substrate in the length direction using a press in the opposite direction (− direction) to the warped direction (+ direction), and the opposite direction (− direction) It was processed so as to warp by a width α (=Y×1.0).

Next, using the cylindrical base material processed as described above, and using the manufacturing apparatus 40 shown in FIG. 7, an ITO cylindrical sputtering target was manufactured as follows.

That is, four ITO cylindrical split target materials with an outer diameter of 153 mm, an inner diameter of 133 mm, and a length of 300 mm, 750 mm, 750 mm, and 300 mm were prepared, and the outer peripheral surface of the cylindrical split target material was masked with a heat-resistant film and tape, and joined. The surface (inner peripheral surface) was undercoated with In solder using an ultrasonic soldering iron.
On the other hand, the bonding surface (peripheral surface) of the cylindrical substrate processed as described above was also undercoated with In solder using an ultrasonic soldering iron.
The cylindrical base material was attached to the base material holding portion 43c to which the Teflon (registered trademark) O-ring 48 was attached.

Next, an O-ring 47 made of Teflon (registered trademark) was attached to the target material holding portion 43b, and one cylindrical divided target material was attached to the target material holding portion 43b. At this time, the lower holding member 43 was used to adjust the displacement between the lower end of the cylindrical substrate and the lower end of the cylindrical split target material to be 0.1 mm. Also, a gap 49 was formed between the cylindrical substrate and the divided cylindrical target material.
Furthermore, the remaining cylindrical split target material was stacked on the cylindrical split target material. A Teflon (registered trademark) O-ring 51 having a thickness of 0.5 mm was interposed between the divided cylindrical target materials. The O-ring 50 is mounted on the uppermost cylindrical split target material, the uppermost cylindrical split target material is attached to the target material holding part 44b, and the cylindrical target material is held by the target material holding part 44b. was pressed from above. At this time, the positions of the nine cylindrical split target materials were adjusted so that all steps between the cylindrical split target materials were 0.2 mm or less. In this manner, the upper end of the cylindrical target material was held by the target material holding member 44 .
Next, the substrate holding portion 45b was pressed against the upper end portion of the cylindrical substrate, and the upper end portion of the cylindrical substrate was held by the substrate holding member 45. As shown in FIG. At this time, while measuring the distance between the surface of the cylindrical target material and the surface of the cylindrical base material with a depth gauge so that the deviation between the upper end of the cylindrical base material and the upper end of the cylindrical target material is 0.1 mm or less, the jig is installed. Adjusted the position.
Finally, the lower holding member 43, the target material holding member 44, and the substrate holding member 45 are fixed to the connecting member 46 made of titanium by means of fixtures 43d, 44c, and 45c, respectively, so that the cylindrical substrate and A cylindrical target material was firmly fixed to the manufacturing apparatus 40 .
The manufacturing apparatus 40, the cylindrical base material and the cylindrical target material were heated to 180°C.
A sufficient amount of melted In solder at 175° C. for joining the cylindrical target material and the cylindrical base material was injected into the gap 49 from the upper side of the target material holding member 44 .
The melted solder injected into the manufacturing apparatus 40, the cylindrical base material, the cylindrical target material and the gap 49 was cooled.
After confirming that the In solder had solidified, the manufactured ITO cylindrical sputtering target (sample) was removed from the manufacturing apparatus 40, the O-ring was removed, and the In solder remaining between the divided cylindrical target materials was scraped out.

In the ITO cylindrical sputtering target (sample) thus produced, the thickness of the bonding material was measured using an ultrasonic flaw detector (manufactured by Hitachi Power Solutions Co., Ltd.: FS LINE) as follows. Specifically, the difference in detection time between the reflected wave at the interface between the target material and the bonding layer and the reflected wave at the interface between the bonding layer and the base material, and the propagation speed of the ultrasonic wave in the bonding layer are used to determine the thickness of the bonding layer. was calculated. A probe of 10 MHz was used, and the propagation speed of ultrasonic waves in the bonding layer (In metal) was set to 2700 m/s.
The thickness of the bonding material is measured at two points in the axial direction of each target segment that are 10 mm apart from both ends of the target segment, and the value obtained by equally dividing these two points is 50 mm or less. Each point is equally divided so that each point in the axial direction is 12 points at intervals of 30° in the circumferential direction (0°, 30°, 60°, . . . and 330°) and did. Each target segment bonded to one base material was measured at the aforementioned positions, and the difference between the maximum value and the minimum value was defined as the thickness difference of the bonding material.
Further, all the step amounts h between adjacent target materials were measured using a depth gauge to obtain the maximum value of the step amount h.
All the axial distances d between adjacent target materials were measured using a feeler gauge, and the difference between the maximum and minimum values was obtained.
The measurement positions of all the step amounts h and the axial distances d between adjacent target materials are 12 positions at intervals of 30° in the circumferential direction (each position of 0°, 30°, 60°, . . . and 330°). and

<Example 2>
An ITO cylindrical sputtering target (sample) was produced in the same manner as in Example 1, except that the longest cylindrical target material was changed to 850 mm, and each value was measured.

<Example 3>
An ITO cylindrical sputtering target (sample) was produced in the same manner as in Example 1, except that the longest cylindrical target material was changed to 1100 mm, and each value was measured.

<Example 4>
An ITO cylindrical sputtering target (sample) was produced in the same manner as in Example 1, except that the longest cylindrical target material was changed to 1450 mm, and each value was measured.

<Example 5>
In Example 4, heating of the cylindrical substrate was changed to non-implementation. That is, instead of heating the cylindrical substrate in an electric furnace and measuring the warp width Y after heating, the central portion in the length direction of the cylindrical substrate is measured using a press without heating. , Pressurized in the direction (- direction) opposite to the warped direction (+ direction), and processed so that it was warped by the width α (= X × 1.0) in the opposite direction (- direction). An ITO cylindrical sputtering target (sample) was produced in the same manner as in Example 4, and each value was measured.

<Example 6>
An IGZO cylindrical sputtering target (sample) was produced in the same manner as in Example 3, except that the material of the cylindrical target material was changed to IGZO, and each value was measured.

<Comparative Example 1>
In Example 2, an ITO cylindrical sputtering target (sample) was produced in the same manner as in Example 2, except that the processing for warping the cylindrical substrate was not performed, and each value was measured.

<Comparative Example 2>
In Example 2, an ITO cylindrical sputtering target (sample) was produced in the same manner as in Example 2, except that in the processing step of warping the cylindrical base material, it was not warped to the opposite side of the originally warped direction, Each value was measured.

Measure the warp width of the cylindrical base material to be used, press the cylindrical base material in the direction opposite to the original warping direction, and warp the cylindrical base material in the opposite direction to the warping direction. Even if the axial length of the cylindrical target material is long, that is, even if at least one cylindrical target material has an axial length of 750 mm or more, the bonding material Even after heating at the time of filling, that is, at the time of filling the bonding material, the cylindrical base material is heated in advance, or the bonding material melted by heating is filled between the cylindrical base material and the target material, and the cylindrical base material Even if the substrate is heated, the effect of warping of the cylindrical base material can be eliminated. It was found that the amount of step between the outer peripheral surfaces can be reduced, and the difference between the maximum and minimum axial distances between adjacent cylindrical target materials can also be reduced.

Reference Signs List 1 sputtering target 2 base material 2a outer peripheral surface 3 target material 4 bonding material 5 dial gauge 40 manufacturing apparatus 43 lower holding member 43b target material holding part 43c base material holding part 43d fixture 44 target material holding member 44b target material holding part 44c fixation Tool 45 Substrate holding member 45b Substrate holding part 45c Fixing tool 46 Connecting member 47 O-ring 48 O-ring 49 Cavity 50 O-ring 51 O-ring

Claims (10)

A method for manufacturing a sputtering target comprising a cylindrical substrate and a cylindrical target material, comprising:
Measure the warp width of the cylindrical base material (referred to as a “measurement step”),
warp the cylindrical substrate so that the cylindrical substrate is warped in the direction opposite to the warped direction (referred to as "reverse warp state") (referred to as "processing step");
A plurality of cylindrical target materials are arranged at intervals in the axial direction outside the processed cylindrical base material in a reverse warped state, and the cylindrical base material and the cylindrical target material are joined with a bonding material. A method for manufacturing a sputtering target, characterized by: 2. The sputtering according to claim 1, wherein in the processing step, a width of warping the cylindrical substrate in a direction opposite to the direction in which the cylindrical substrate is warped is determined based on the warp width measured in the measuring step. How the target is made. In the processing step, when the warp width X is measured in the measuring step, the cylindrical substrate is warped from the linear axis in the direction opposite to the warp direction by a width of X × 0.10 to 2.00. 3. The method for producing a sputtering target according to claim 1, wherein the cylindrical base material is warped so as to form a state . In the measuring step, after heating the cylindrical base material, measuring the warp width of the cylindrical base material after heating,
In the processing step, when the warp width Y is measured in the measurement step, processing is performed to warp the cylindrical base material by a width of Y×0.50 to 1.50 in a direction opposite to the direction in which it was warped. The method for manufacturing a sputtering target according to claim 1 or 2, characterized by: Manufacture of the sputtering target according to claim 4, wherein in the measuring step, the warp width Y of the cylindrical substrate after heating is measured after heating the cylindrical substrate to 150 to 300 ° C. Method. 6. The method of manufacturing a sputtering target according to claim 1, wherein, in said measuring step, a width of displacement of the outer peripheral surface of the cylindrical substrate is measured as a warp width. 7. The method for producing a sputtering target according to claim 1, wherein at least one of said cylindrical target materials has an axial length of 750 mm or more. In the manufactured sputtering target, the difference between the maximum and minimum thickness of the bonding material is 1.0 mm or less, and the maximum step amount between the outer peripheral surfaces of adjacent cylindrical target materials is 0.5 mm or less. , and the difference between the maximum and minimum axial distances between adjacent cylindrical target materials is 0.2 mm or less. A sputtering target comprising a cylindrical base material and a cylindrical target material, wherein the cylindrical base material and the cylindrical target material are joined with a bonding material,
At least one of the cylindrical target materials has an axial length of 750 mm or more, a difference between the maximum thickness and the minimum thickness of the bonding material is 1.0 mm or less, and the adjacent cylindrical target materials have a thickness difference of 1.0 mm or less. A sputtering target having a maximum step amount between outer peripheral surfaces of 0.5 mm or less, and a difference between the maximum and minimum axial distances between adjacent cylindrical target materials of 0.2 mm or less. 10. The sputtering target according to claim 9, wherein the cylindrical substrate has a length of 2 m or more.

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