JP4974198B2 - Copper material used for sputtering target and method for producing the same - Google Patents

Description

  The present invention relates to a copper material used as a sputtering target and a method for producing the same.

  In recent years, flat panel displays have been used in various sizes from small electronic devices such as mobile PCs and mobile phone terminals to large televisions. In liquid crystal displays and organic EL displays, which are classified as flat panel displays, thin film transistor (hereinafter referred to as TFT) elements are incorporated in the pixel dots in order to meet the demands for high-quality and high-speed drawing of moving images. Has been developed and is now mainstream.

  FIG. 1 is a cross-sectional view showing an example of the structure of a TFT element in a liquid crystal display. The TFT element 1 includes a scanning electrode 3 on a glass substrate 2 and a gate electrode 4 in which a part of the scanning line functions as a TFT ON / OFF control. The gate electrode is formed so as to be covered with an insulating film 5 of silicon nitride, and an amorphous silicon (hereinafter referred to as a-Si) layer 6 and an a-Si layer 7 doped with P (phosphorus) are sequentially formed on the insulating film 5. Source-drain electrodes 8 and 9 are formed. A silicon nitride protective film 10 is formed so as to cover them. A tin-doped indium oxide (hereinafter referred to as ITO) film 11 is disposed in the pixel region.

  Conventionally, refractory metals such as Mo and Cr, aluminum and alloys thereof have been used for scanning lines, gate electrodes, and source-drain electrodes. However, as the liquid crystal display is enlarged and the number of pixels is increased, the wiring length is increased, and problems such as image display unevenness due to signal delay, power loss, etc. have become apparent. Therefore, attention has been focused on copper wiring with low electrical resistivity.

  The problem with using a copper wiring film for TFT element wiring is that when a Cu film is formed directly on a glass substrate, the Cu wiring film peels off from the glass due to poor adhesion at the Cu / glass interface. It is done.

  As an invention for solving the problem of peeling, techniques described in Patent Documents 1 to 3 and the like have been proposed.

  In Patent Document 1, peeling is suppressed by interposing a refractory metal such as molybdenum between the copper wiring and the glass substrate and forming a barrier layer having excellent adhesion to the glass substrate.

  In Patent Documents 2 and 3, by using a target obtained by alloying copper, an oxide is formed at the interface between the copper wiring and the glass substrate, and an alloy element is concentrated at the interface between the copper wiring and the glass substrate. Peeling is suppressed.

  Techniques such as copper alloying have also been developed as in the inventions of Patent Documents 2 and 3, but currently industrially, Mo and Ti having good adhesion to glass, as in the invention described in Patent Document 1, are used. The barrier layer 12 shown in FIG. 1 is formed under the copper wiring to improve peeling, and a pure copper wiring is formed by sputtering.

  One of important characteristics required in the process of forming the gate electrode of the TFT element is the uniformity of the wiring film within the substrate surface. Due to the uniformity of the film, that is, the difference in film thickness and the presence of irregularities, the electric capacity in the TFT becomes non-uniform, which adversely affects the display. In addition, in the TFT element manufacturing process, if there is a difference in film thickness or coarse clusters (particles, splashes, etc.), wiring defects such as disconnection and short circuit may occur when wiring electrodes are created by etching. Is done.

  In the case of forming a pure copper film to be a semiconductor wiring or the like in the sputtering process, the invention of a sputtering target capable of forming a uniform wiring film and suppressing coarse clusters and suppressing disconnection failure is described in Patent Documents 4 to 8, etc. Technology has been proposed.

  Patent Document 4 discloses that a defective disconnection is produced by melting and solidifying copper having a purity of 99.9999% or more excluding oxygen, nitrogen, carbon and hydrogen gas components at an oxygen concentration of 0.1 ppm or less. A sputtering target capable of obtaining wiring for VLSI with a low rate is described. By reducing the amount of impurities in the copper material, disconnection defects and the like are reduced.

  Patent Document 5 uses a sputtering target in which the average crystal grain size of the recrystallized structure is 80 microns or less and the Vickers hardness is 100 or less in copper having a purity of 99.995% or more. It is described that the expansion of protrusions and the generation of coarse clusters are suppressed.

Patent Document 6 discloses that in copper having a purity of 99.999% or more excluding gas components, the X-ray diffraction peak intensity I (111) of the (111) plane in the sputtering surface is increased, and the average particle size is 250 μm or less. In addition, it is described that the uniformity of the film thickness is improved by setting the variation of the particle diameter depending on the location within 20%.
In Patent Document 7, the volume of crystals facing the (110) plane on the surface is set to 80% or more, and the crystals are uniformly distributed from the surface to the center, so that the jumping out of copper atoms is perpendicular to the surface, It describes that it is possible to form a film up to a deep part of a groove having a large aspect ratio.
In Patent Document 8, in copper having a purity of 99.999% or more, the average crystal grain size is controlled to 10 to 30 μm, and each of the orientations of (111), (200), (220), and (311) is provided. It is described that uniformity and minimal particle generation can be achieved by having a random orientation with less than 50% of the particles.

  By controlling the components, crystal grain size, strain and crystal orientation, it has become possible in the conventional invention to control spattering of sputtered particles and suppress uniform film formation and coarse clusters. However, the size of the substrate such as a liquid crystal display for a large television has been increased, and the substrate size exceeding 2 m, such as 1870 mm × 2200 mm, has been achieved in the seventh generation. Accordingly, it is necessary to form a film on a large substrate also in the sputtering process for creating the wiring, and even if the method described in the above patent document is used, the thickness of the generated wiring film is different for each part of the substrate. The problems such as non-uniformity and the generation of coarse clusters become more obvious. Further, since the sputtering target itself used is also increased in size, the metal structure tends to be non-uniform for each portion of the sputtering target material, and the influence on film thickness accuracy and coarse cluster formation is increased.

JP-A-7-66423 Japanese Patent No. 4065959 JP 2008-166742 A Japanese Patent No. 3727115 Japanese Patent No. 3975414 Japanese Patent No. 3403918 Japanese Patent No. 3997375 Japanese Patent No. 3971171

  In view of the above-mentioned conventional problems, the present invention generates particles more uniformly than in the prior art when creating wiring in a sputtering process for a large substrate used in a TFT liquid crystal panel or the like, and It is an object of the present invention to provide a copper material for a sputtering target in which the generation frequency of the particles hardly changes even during use.

The inventors of the present invention have made extensive researches on the above-described problems, and thereby the variation in the crystal grain size within the plane and the plane between the plane and the depth from the sputtering plane. Baratsuki in, found that by controlling the same variation of the hardness in addition to the Re this is, it is possible to provide a suitable copper materials can be fabricated sputtering target uniform wiring film.
The present invention has been made based on this finding.

That is, the present invention
(1) A method for producing a copper material for a sputtering target, the step of hot rolling or hot extruding high purity copper having a purity of 99.99% or more at a heating temperature of 700 to 1000 ° C., and the heat Including a step of water-cooling at a cooling rate of 50 ° C./second or more immediately after hot rolling or hot extrusion ,
It is made of the above-mentioned high-purity copper, and has a sputtering surface, a surface parallel to the sputtering surface at a position of 1/4 plate thickness from the sputtering surface in the plate thickness depth direction, and 1 / plate from the sputtering surface to the plate thickness depth direction. The arithmetic average of the crystal grain size measured on the plane parallel to the sputtering surface at the position of two plate thicknesses is 100 to 200 μm, and the standard deviation of the crystal grain size is 10 μm within each measurement plane and between each measurement plane. And a sputtering surface, a surface parallel to the sputtering surface at a position of ¼ plate thickness from the sputtering surface to the plate thickness depth direction, and a ½ plate from the sputtering surface to the plate thickness depth direction. The arithmetic average of the hardness measured on the plane parallel to the sputtering surface at the thickness position is 51 to 100 Hv, and the standard deviation of the hardness is within each measurement surface and between each measurement surface. A method for producing a copper material for sputtering target, characterized by obtaining a copper material for sputtering target that is within 5 Hv,
(2) The method for producing a copper material for a sputtering target according to the item (1), comprising a step of cold rolling so that a total of the cold rolling ratios is 30% or less after the water cooling. ,
( 3) High-purity copper having a purity of 99.99% or more is subjected to hot rolling or hot extrusion at a heating temperature of 700 to 1000 ° C., and a cooling rate of 50 ° C./right after the hot rolling or hot extrusion. Obtained by water cooling for at least 2 seconds, and having a purity of 99.99% or more, a sputtering surface, a surface parallel to the sputtering surface at a position of 1/4 plate thickness from the sputtering surface in the plate thickness depth direction, and The arithmetic averages of the crystal grain sizes measured on the plane parallel to the sputtering plane at a position of ½ thickness from the sputtering plane in the thickness direction are 100 to 200 μm, respectively. In the meantime, the standard deviation of the crystal grain size is within 10 μm, and the sputtering surface, the surface parallel to the sputtering surface at a position of ¼ plate thickness from the sputtering surface in the plate thickness depth direction, and the sputtering The arithmetic average of the hardness measured on the plane parallel to the sputtering surface at the position of 1/2 plate thickness in the plate thickness depth direction is 51 to 100 Hv, respectively, between each measurement surface and between each measurement surface, A standard deviation of the hardness is within 5 Hv, a copper material for a sputtering target , and
(4) The copper material for a sputtering target according to the item (3), which is obtained by cold rolling so that the sum of the cold rolling ratios is 30% or less after the water cooling <br>/> Is provided.

According to the present invention, a copper material suitable for a sputtering target capable of producing a uniform wiring film can be provided. The copper material for sputtering target of the present invention generates particles more uniformly than before when creating wiring in a sputtering process on a large substrate used for a TFT liquid crystal panel or the like, and even during use Changes in the frequency of the particles are unlikely to occur.
The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

It is a schematic sectional drawing which shows an example of the structure of the TFT element in a liquid crystal display. 6 is an explanatory diagram of sampling of a measurement test in Example 1. FIG. 6 is an explanatory diagram of sampling of a measurement test in Example 2. FIG.

The copper material for a sputtering target of the present invention is obtained through the above specific manufacturing process, and in high-purity copper (hereinafter, simply referred to as “pure copper”) having a purity of 99.99% or more, the sputtering in-plane and the crystal grain size of the microstructure in the sputtering surface and a plane parallel internal plates to a specific range, in which a specific range of hardness to further.

  The copper material for the sputtering target needs to have a purity (mass base) of 99.99% or more. Electrolytic copper, which is a raw material for producing a pure copper ingot, contains a certain amount of impurities, and they also appear in the pure copper ingot. In particular, it is desirable that the impurities contain B, Al, Si, P, As, Sb, and Bi in an amount of 5 ppm or less. This is because these elements are elements used as dopants for Si semiconductors and may adversely affect semiconductor characteristics. A more preferable purity is 99.995% or more.

Since the copper material for the sputtering target is required to have a uniform structure, it is desirable that the non-uniform structure formed by casting solidification is broken by hot rolling or hot extrusion to have a recrystallized structure. When the crystal grain size of the recrystallized structure is small, the total area of the crystal grain boundary is incidentally increased, but the crystal grain boundary is a part where the atomic arrangement is disturbed, and the ease of element jumping during sputtering is within the grain. Unlike this, the film to be formed tends to be non-uniform. In addition, when the crystal grain size is large, high energy is required to make the target material fly off, and a large number of target atoms solidify and fly out, so that the formation of coarse clusters tends to be nonuniform. In the present invention, the arithmetic average of the crystal grain size is 100 to 200 μm, preferably 120 to 180 μm, and more preferably 130 to 170 μm.

Suppressing the variation of crystal grains is important for controlling the jumping out of the target material and forming a uniform film. The sputtering target material is scraped in the plate thickness direction during use, and is exchanged using about 1/3 to 1/2 of the plate thickness. In order to perform uniform film formation by sputtering, uniformity within the surface of the target and within the plate is required. The standard deviation of the grain size distribution on the sputtering surface (one flat plate surface in the case of a flat plate) and on the plane parallel to the sputtering surface at 1/4 and 1/2 plate thickness positions from the sputtering surface is within 10 μm. By controlling to, a sputtering target having a uniform metal structure on the entire surface can be provided, and uniform film formation by sputtering becomes possible. When the standard deviation exceeds 10 μm, a non-uniform metal structure is formed and a uniform film cannot be formed. Within each measurement plane and between each measurement plane, the standard deviation of the crystal grain size is preferably 8 μm or less, and more preferably 6 μm or less.
In the present invention, the number of samples for measuring the crystal grain size is 6 or more on each surface. The measurement points are equally divided into at least three in the longitudinal direction on each surface, and the number of measurements in each divided region is measured to be equal. The crystal grain size at each measurement location is the average grain size (crystal grain size) measured by JIS H 0501 (cutting method).

Further, it is preferable to control the strain inherent in the copper material in order to affect the jumping out of the target material. When the strain inherent in the material varies from site to site, the energy differs from the surroundings, and the target material jumps out from site to site, making uniform film formation impossible. The strain inside the copper material can be evaluated by measuring the hardness. By controlling the inherent strain using hardness as a guide, a copper material with less variation can be provided. In the present invention, the arithmetic mean of the hardness ((micro) Vickers hardness) is 5 1～100Hv, good Mashiku is 51～90Hv. If the strain is too much, that is, the hardness is too hard, a large number of target atoms will harden and fly out, the formation of coarse clusters will increase, and the formed film will tend to be non-uniform, and it is desirable that the hardness be 100 Hv or less. In general, in oxygen-free copper (C1020), when completely heat-recrystallized or annealed and subjected to a heat treatment with the lowest tensile strength (O material), the hardness is 51 to 59 Hv, “Copper product data Book (2nd edition) "(edited by Japan Copper and Brass Association, published 31st March 2009, 2nd edition, page 61), and the value was set as the lower limit of the above preferred range.

In addition, adjustment of hardness is performed by cold working such as rolling, and the upper limit value of a preferable range of hardness can be 100 Hv or less by suppressing the working rate of cold working to about 30% or less. A copper material having a hardness of 51 to 100 Hv can be easily obtained.
As described above, cold working is performed to adjust the hardness. The processing rate is 0%, that is, the hardness in a completely annealed state (O material) is 51 to 59 Hv, and the hardness is gradually improved as the processing rate is increased to 100 Hv at a processing rate of 30%. To reach. If the processing rate is too high, it exceeds 100 Hv, and the above-mentioned problem occurs.

The Te present invention odor, like the crystal grain size, the sputtering surface and, 1/4 thickness and 1/2 control within the standard deviation 5Hv the hardness distribution in the sputtering surface parallel to the plane of the sheet thickness position By doing so, a sputtering target having a uniform metal structure on the entire surface can be provided, and uniform film formation by sputtering becomes possible. When the standard deviation of hardness exceeds 5 Hv, a non-uniform metal structure is formed and uniform film formation cannot be performed. During each measurement plane and the measuring plane, the standard deviation of the hardness is good preferable or less 3HV.
In the present invention, the number of samples for measuring the hardness is 6 or more on each surface. The measurement points are equally divided into at least three in the longitudinal direction on each surface, and the number of measurements in each divided region is measured to be equal.

Method for producing a copper material for the sputtering target of the present invention, in order to control the crystal grain size and hardness at the internal scan sputtering surface and the plate is preferably noted following shown points in the manufacturing process. Manufacturing method of the copper material in the present invention, melting and casting - hot rolling or hot extrusion - cold rolling - Take a heat treatment process. Further, a chamfering step may be included between hot rolling or hot extrusion and cold working. Further, cold rolling and heat treatment may be repeated . By manufacturing in mind that in the following, a copper material that satisfies the requirements of the aforementioned metallic structure becomes possible manufacturing, as target material for larger displays, such as performing a target produced by combining the strip-shaped plate The effect of facilitating uniform formation of the sputtering film when used is obtained.

In hot rolling or hot extrusion , dynamic recrystallization occurs during processing, and the formed recrystallized grains grow while the material temperature is still high. In a copper material used as a sputtering target, it is preferable to control this step in order to determine the crystal grain size by this hot rolling or hot extrusion .

In the conventional hot rolling process, after dynamic recrystallization occurs, it takes a long time to be exposed to the atmosphere, and it is difficult to control the crystal grain size to a desired size. In addition, since the edge of the plate is greatly cooled in the atmosphere, there is a problem that the crystal grain size becomes uneven at the width direction end, the longitudinal end, and the center of the material.
When performing hot rolling process, the present invention, hot rolling, by a water-cooled at a cooling rate 50 ° C. / sec or more immediately after the heat-rolling, controlling the desired size of grains Can do. Here, immediately after the hot rolling it will have to be within 60 seconds after leaving the furnace Lumpur. The term “ immediately after hot extrusion” means that it is within 10 seconds after being extruded from a die.

The heating temperature of the material consisting of pure copper before hot rolling intends rows in the range of 700 to 1000 ° C.. When the heating temperature of the material is lower than 700 ° C., sufficient dynamic recrystallization does not occur during rolling , and a uniform metal structure cannot be obtained. When the temperature is higher than 1000 ° C., it is difficult to control the crystal grain size. During hot rolling, it is necessary not to stagnate the material in order to avoid local cooling of the material edge and the like due to heat removal from the transport roll and side edge roll. By avoiding cooling from the end, a uniform structure can be obtained over the entire surface of the material, and variations in crystal grain size and hardness inside the copper material can be reduced. Hot rolling is performed a plurality of passes, but it is desirable to cool by water cooling after the final pass. In order to set the crystal grain size to the above-mentioned 100 to 200 μm, the time from immediately after the final pass to water cooling is within 60 seconds, and the cooling rate of water cooling is 50 ° C./second or more , preferably 70 ° C./second or more. you to.

  The cooling rate is more preferably 100 ° C./second or more. The upper limit of the cooling rate is not particularly limited, but in practice, it is usually about 300 ° C./second or less. Moreover, it is preferable to perform cooling until a material becomes 200 degrees C or less.

In the present invention, a hot extrusion process is preferable to hot rolling because the crystal grain size and hardness can be controlled more strictly. In the hot extrusion process of the present invention, the extruded material can be immediately water-cooled without being exposed to the atmosphere, so that it is possible to cool at a high rate immediately after dynamic recrystallization. Therefore, a metal structure with little variation in temperature inside the material and a very small variation in crystal grain size and hardness in the longitudinal direction (direction from the front end to the rear end of the extruded material) and the width direction can be obtained . When performing in hot extrusion process, it intends row processing temperature of the hot extrusion material before the range of 700 to 1000 ° C.. When the heating temperature of the material is lower than 700 ° C., sufficient dynamic recrystallization does not occur during extrusion, and it is difficult to obtain a uniform metal structure. When the temperature is higher than 1000 ° C., it is difficult to control the crystal grain size. The crystal grain size in the aforementioned 100~200μm is it cooling rate immediately after the hot extrusion to above 50 ° C. / sec.

The cooling rate is more preferably 100 ° C./second or more. The upper limit of the cooling rate is not particularly limited, but in practice, it is usually about 300 ° C./second or less. Moreover, it is preferable to perform cooling until a material becomes 200 degrees C or less.
On the other hand, in hot forging, it is difficult to eliminate non-uniform cooling after forging at a size corresponding to the recent demand for larger targets, and a uniform crystal grain structure cannot be obtained.

The material after hot rolling or hot extrusion may be tempered by cold rolling and annealing. The total cold working rate is desirably 30% or less (including 0%, which means that rolling is not performed). When the total of the cold working rates exceeds 30%, the amount of strain inside the material increases, and the specified value of hardness tends to be exceeded.

It cooled immediately after said passing Rinetsu extrusion or hot rolling, the material produced perform cold rolling if necessary, preferably plate-like material, the target by any machining or the like of the turning etc. Processed to shape and used for sputtering.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

Example 1
(Invention Examples 1 to 3, Comparative Examples 5 to 7)
Ingots having a thickness of 150 mm, a width of 220 mm, and a length of 2100 mm with the purity (mass%) shown in Table 1-1 were produced. After heating them at the heating temperature shown in Table 1-1, hot rolling was performed to produce a base plate having a thickness of 23 mm, a width of 220 mm, and a length of about 13 m. During the hot rolling, the material was not stagnated on the transport roll, and the time from the final pass to water cooling was 45 seconds. Water cooling was carried out at a rate of 50 ° C./second or higher as shown in Table 1-1 by passing through a water cooling zone equipped with a shower. Next, the oxide film on the surface of the obtained base plate was chamfered to a plate thickness of 22 mm, and then cold rolled to a thickness of 20 mm × width of 220 mm, and the edge portion was cut and removed to obtain a thickness of 20 mm × width. Copper materials for sputtering targets of Invention Examples 1 to 3 and Comparative Examples 5 to 7 having a flat plate size of 200 mm × length of about 12 m were prepared.

(Comparative Example 8)
A copper material for a sputtering target of Comparative Example 8 was prepared in the same manner as Examples 1 to 3 except that the number of seconds from the final pass to water cooling was 90 seconds.

(Comparative Example 9)
A copper material for a sputtering target of Comparative Example 9 was prepared in the same manner as in Examples 1 to 3 except that the water cooling rate was set to 12 ° C./second. The change of the water cooling rate was adjusted by the passing speed and the shower flow rate in the water cooling zone.

(Comparative Example 10)
A copper material for a sputtering target of Comparative Example 10 was prepared in the same manner as in Inventive Examples 1 to 3, except that water cooling was not performed.

(Invention Example 4)
Example 4 of the present invention was carried out in the same manner as Examples 1 to 3 of the present invention except that the thickness after hot rolling was 28 mm, the oxide film on the surface was chamfered to 27 mm, and then cold rolled. A copper material for a sputtering target was prepared.

(Comparative Example 11)
Sputtering of Comparative Example 11 was carried out in the same manner as in Examples 1 to 3 of the present invention except that the thickness after hot rolling was 31 mm, the oxide film on the surface was chamfered to 30 mm, and then cold rolled. A copper material for the target was prepared.

About the flat copper material 21 of the present invention example and the comparative example thus obtained, the plate surface 22 shown in the explanatory view based on the schematic perspective view of FIG. 2, from the plate surface 22 to the plate thickness depth direction. Each of the surface 23 parallel to the plate surface 22 at the 1/4 plate thickness position and the surface 24 parallel to the plate surface 22 at the 1/2 plate thickness position from the plate surface 22 in the plate thickness depth direction Direction center part (31, 41, 51) and side (end) part (32, 42, 52), longitudinal center part (longitudinal center) ) In the width direction at the central portion (33, 43, 53) and side (end) portions (34, 44, 54) in the width direction, and at the center portion (35, 45, 55) and side (end) parts (36, 46, 56), a total of 18 places There are, grain size, and hardness were measured by the following method.
2A is a perspective view showing the entirety of the copper material 21. In FIG. 2A, a dotted line 25 is a ¼ plate thickness from the plate surface 22 in the plate thickness depth direction. The dotted line 26 indicates the position of 1/2 plate thickness from the plate surface 22 in the plate thickness depth direction.
2B to 2C correspond to exploded perspective views of the copper materials 21a, 21b, and 21c obtained by disassembling the copper material 21 of FIG. 2A along dotted lines 25 and 26, respectively.

  Moreover, as shown in the explanatory view based on the schematic perspective view of FIG. 3, from the copper material 21 of the flat plate of the present invention example and the comparative example, at the position of the plate surface 22 and from the plate surface 22 to ¼ plate thickness. The rolling tip (longitudinal tip) (61, 64, 67) is a surface 23 parallel to the plate surface 22 and a surface 24 parallel to the plate surface 22 at a position of 1/2 plate thickness from the plate surface 22. ), The central portion (longitudinal center) (62, 65, 68), and the rear end portion (longitudinal rear end) (63, 66, 69), a total of nine locations, each of the surfaces 22, 23, 24 A circular plate having a diameter of 6 inches was cut out so as to be the target surface (sputtering surface), and the sputtering characteristics were investigated by the following method. 3 is an overall perspective view (FIG. 3A) and an exploded perspective view (FIGS. 3B to 3C) of the copper material 21 similar to FIG. 2, and is the same as the reference numerals in FIG. The symbols have the same meaning as in FIG.

[1] Crystal grain size The crystal grain size in the copper material plate was measured based on JIS H 0501 (cutting method) by observing the microstructure in the above-described portions 31 to 36, 41 to 46, and 51 to 56.
[2] Hardness The hardness of the copper material plate was measured with a micro Vickers hardness tester in accordance with JIS Z 2244 on the surfaces in the above-described portions 31 to 36, 41 to 46, and 51 to 56. .
[3] Sputtering characteristics The obtained copper material plate was cut into a diameter of 6 inches (15.24 cm) and a thickness of 6 mm at positions 61 to 69 shown in FIG. In order to exclude the influence of the roughness of the target surface, the roughness was all adjusted by polishing the maximum roughness Ra to 0.5 to 0.8 μm. Using the sputtering target created as described above, a DC magnetron sputtering apparatus was used to perform sputtering on an OA-10 glass substrate manufactured by Nippon Electric Glass Co., Ltd., thereby producing a 0.3 μm thick copper wiring. . The sputtering conditions were an Ar gas pressure of 0.4 Pa and a discharge power of 12 W / cm ² . Thereafter, heat treatment was performed in a vacuum at 300 ° C. for 30 minutes. Ten film thicknesses of the copper wiring after the heat treatment were measured. A plate with a maximum film thickness and a minimum film thickness range of ± 7% at 90 points of total data of nine target materials cut out from the same plate is judged as “good”, and a plate with more variation than that is judged as “bad”. did.

The results of [1] to [3] are shown in Table 1-2. The examples of the present invention all exhibit good sputtering characteristics. Since Comparative Example 5 had a large amount of impurities, the sputtering characteristics were poor. In Comparative Examples 6, 7, 9 and 10, the crystal grain size and the standard deviation thereof deviated from the specified values, so that the sputtering characteristics were poor. In Comparative Example 8, the standard deviation of the crystal grain size and the hardness both deviated from the specified values, resulting in poor sputtering characteristics.
Further, in Comparative Example 11, since the specified value of the hardness arithmetic average deviated, a film having a uniform thickness was not obtained, and the sputtering characteristics were poor.

Example 2
(Invention Examples 101 to 103, Comparative Examples 105 to 108)
A pure copper ingot having a purity shown in Table 2-1 having a diameter of 300 mm and a length of 800 mm was produced and used as a billet for hot extrusion. After heating the billet to the heating temperature shown in Table 2-1, extrusion is performed, and then the extruded material is immediately water-cooled to 150 ° C. or less at the cooling rate shown in Table 2-1. I got a plate. Subsequently, the base plate was cold-rolled to produce copper materials for sputtering targets of Invention Examples 101 to 103 and Comparative Examples 105 to 108 of flat plates having a thickness of 20 mm × width of 200 mm × length of about 12 m.

(Invention Example 104)
After the extrusion, the base plate was made to have a thickness of 27 mm, and the copper material for a sputtering target of Example 104 of the invention was used in the same manner as Examples 101 to 103 of the invention except that a flat plate having a thickness of 20 mm was prepared by cold rolling. Created.

(Comparative Example 109)
After the extrusion, a base plate was prepared with a thickness of 30 mm, and a copper material for a sputtering target of Comparative Example 109 was prepared in the same manner as in Invention Examples 101 to 103 except that a flat plate having a thickness of 20 mm was prepared by cold rolling. did.

  The obtained flat plate obtained by hot extrusion was examined for crystal grain size, hardness, and sputtering characteristics in the same manner as in Example 1, as in Example 1. The results are shown in Table 2-2.

As in the results shown in Table 2-2, the inventive examples 101 to 104 all satisfy the characteristics. Since Comparative Example 105 had a large amount of impurities, the sputtering characteristics were poor. In Comparative Example 106, the deformation resistance of the material during hot extrusion was too high, and the sample could not be obtained because the material could not be extruded properly. In Comparative Examples 107 and 108, the arithmetic average and standard deviation of the crystal grain size were not specified, so that the sputtering characteristics were poor. In Comparative Example 109, the standard value of the hardness arithmetic average deviated, so that a film having a uniform thickness was not obtained and the sputtering characteristics were poor.

DESCRIPTION OF SYMBOLS 1 TFT element 2 Glass substrate 3 Scan line 4 Gate electrode 5 Insulating film 6 Amorphous silicon layer 7 Amorphous silicon layer doped with phosphorus 8, 9 Source-drain electrode 10 Protective film of silicon nitride 11 Tin-doped indium oxide film 12 Barrier layer 21 Flat plate Copper material of 22 Plate surface 23 Parallel to the plate surface at the 1/4 plate thickness position from the plate surface to the plate thickness depth 24 Parallel to the plate surface at the 1/2 plate thickness position from the plate surface to the plate thickness depth direction Surface 25 Position of 1/4 plate thickness from plate surface to plate thickness depth 26 Position of 1/2 plate thickness from plate surface to plate thickness depth direction

  While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

  This application claims priority based on Japanese Patent Application No. 2009-216579, filed in Japan on September 18, 2009, which is incorporated herein by reference. Capture as part.

Claims (4)

A method of manufacturing a copper material for sputtering targets, comprising the steps of purity to hot extrusion-rolling or heat at a heating temperature of 700 to 1000 ° C. The high-purity copper is 99.99% or higher, the heat-rolled or Including a step of water cooling immediately after the hot extrusion at a cooling rate of 50 ° C./second or more,
It is made of the above-mentioned high-purity copper, and has a sputtering surface, a surface parallel to the sputtering surface at a position of 1/4 plate thickness from the sputtering surface in the plate thickness depth direction, and 1 / plate from the sputtering surface to the plate thickness depth direction. The arithmetic average of the crystal grain size measured on the plane parallel to the sputtering surface at the position of two plate thicknesses is 100 to 200 μm, and the standard deviation of the crystal grain size is 10 μm within each measurement plane and between each measurement plane. And a sputtering surface, a surface parallel to the sputtering surface at a position of ¼ plate thickness from the sputtering surface to the plate thickness depth direction, and a ½ plate from the sputtering surface to the plate thickness depth direction. The arithmetic average of the hardness measured on the plane parallel to the sputtering surface at the thickness position is 51 to 100 Hv, and the standard deviation of the hardness is within each measurement surface and between each measurement surface. The manufacturing method of the copper material for sputtering targets characterized by obtaining the copper material for sputtering targets which is less than 5Hv.   The method for producing a copper material for a sputtering target according to claim 1, further comprising a step of cold rolling so that a total of the cold rolling ratios is 30% or less after the water cooling. High-purity copper having a purity of 99.99% or more is subjected to hot rolling or hot extrusion at a heating temperature of 700 to 1000 ° C., and immediately after the hot rolling or hot extrusion , at a cooling rate of 50 ° C./second or more. From the sputtering surface obtained by water cooling and having a purity of 99.99% or more, a surface parallel to the sputtering surface at a position of ¼ plate thickness from the sputtering surface in the plate thickness depth direction, and the sputtering surface The arithmetic average of the crystal grain size measured on the plane parallel to the sputtering surface at the position of ½ plate thickness in the plate thickness direction is 100 to 200 μm, respectively, and between each measurement surface and each measurement surface, The standard deviation of the crystal grain size is within 10 μm, and the sputtering surface, the surface parallel to the sputtering surface at a position of ¼ plate thickness from the sputtering surface in the plate thickness depth direction, and the plate from the sputtering surface Arithmetic averages of hardness measured on a plane parallel to the sputtering surface at a position of ½ plate thickness in the thickness direction are 51 to 100 Hv, respectively, and the hardness is measured in each measurement surface and between each measurement surface. A copper material for a sputtering target, wherein the standard deviation of the thickness is within 5 Hv.   The copper material for a sputtering target according to claim 3, wherein the copper material for the sputtering target is obtained by cold rolling so that a total of the cold rolling ratios is 30% or less after the water cooling.

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