JP2010037579A - Oxygen-free copper sputtering target, and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen-free copper sputtering target in which the difference in the advance of target erosion is reduced between a joined part and a non-joined part, and the manufacturing method of the same. <P>SOLUTION: The oxygen-free copper sputtering target 1 is formed of a copper material consisting of oxygen-free copper of purity of ≥3N, and includes a first plate 20 and a second plate 22 whose mean crystal grain size is ≥0.04 mm and ≤0.1 mm, and a joined part 10 formed of the first plate 20 and the second plate 22 between the first plate 20 and the second plate 22 and having the mean crystal grain size of ≥0.04 mm and ≤0.06 mm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an oxygen-free copper sputtering target material and a method for producing an oxygen-free copper sputtering target material. In particular, the present invention relates to an oxygen-free copper sputtering target material capable of stable sputtering and a method for producing an oxygen-free copper sputtering target material.

  As conventional sputtering target materials, metal plates of the same quality are butted together and joined by a friction stir welding method, and the average crystal grain size of the metal crystal at the joint is 20 to 500 of the average crystal grain size of the metal crystal at the non-joint part. % Is a sputtering target material (see, for example, Patent Document 1).

  In the sputtering target material described in Patent Document 1, the average crystal grain size of the metal crystal at the joint is set to 20 to 500% of the average crystal grain size of the metal crystal at the non-joint part. A film can be formed on an object.

Japanese Patent Laid-Open No. 2004-307906

  However, when the sputtering target material according to Patent Document 1 is subjected to heat treatment, there is a large difference between the average crystal grain size of the metal crystal in the joint portion and the average crystal grain size of the metal crystal in the non-joint portion. There is a difference in the average crystal grain size between the bonded portion and the erosion of the sputtering target due to the progress of sputtering. As a result, there may be a difference between the bonded portion and the non-bonded portion.

  Accordingly, an object of the present invention is to provide an oxygen-free copper sputtering target material and a method for producing an oxygen-free copper sputtering target material in which the difference in the progress of target erosion between the bonded portion and the non-bonded portion is reduced. .

  In order to achieve the above object, the present invention provides a first plate material and a second plate material which are formed from a copper material made of oxygen-free copper having a purity of 3N or more and whose average crystal grain size is 0.04 mm or more and 0.1 mm or less. A plate member, and a joining portion formed between the first plate member and the second plate member and having an average crystal grain size of 0.04 mm to 0.06 mm between the first plate member and the second plate member. An oxygen free copper sputtering target material is provided.

  Moreover, you may form the said oxygen-free copper sputtering target material which has a larger planar dimension than the planar dimension in the top view of the glass substrate for display panels.

  Moreover, in order to achieve the above object, the present invention provides a plate material preparing step of preparing a plurality of plate materials made of a copper material made of oxygen-free copper, a side surface of one plate material of the plurality of plate materials, and the other plate material A joining step for joining the side surfaces of the two plate members, a joining step for joining the butted portions formed by abutting the side surfaces of one plate member and the other plate member by friction stir welding, and a joining portion. In addition, the one plate material and the other plate material joined to each other by the joint portion are subjected to heat treatment in vacuum to coarsen the crystal of the joint portion, and the portion obtained by removing the joint portion from the one plate material and the other plate material. There is provided a method for producing an oxygen-free copper sputtering target material comprising a heat treatment step for generating recrystallized grains in a certain non-bonded portion.

  Moreover, the manufacturing method of the said oxygen-free copper sputtering target material prepares the several board | plate material whose average crystal grain diameter is 0.2 mm or less at a board | plate material preparation process, and a joining process has an average crystal grain diameter of 0.02 mm. The bonded portion may be formed with a thickness of 0.03 mm or less, and the heat treatment step forms a bonded portion with an average crystal grain size of 0.04 mm or more and 0.06 mm or less from the bonded portion, and the average from the non-bonded portion. You may form the non-joining part whose crystal grain diameter is 0.04 mm or more and 0.1 mm or less.

  According to the oxygen-free copper sputtering target material and the method for producing an oxygen-free copper sputtering target material according to the present invention, the oxygen-free copper sputtering target material in which the difference in the progress of target erosion is reduced between the bonded portion and the non-bonded portion. And the manufacturing method of an oxygen free copper sputtering target material can be provided.

[Embodiment]
(Configuration of oxygen-free copper sputtering target material 1)
FIG. 1 shows an example of a partial perspective view of an oxygen-free copper sputtering target material according to an embodiment of the present invention.

  As an example, the oxygen-free copper sputtering target material 1 according to the present embodiment includes a first plate material 20 and a second plate material 22 made of a predetermined copper material for electronic components, and a first plate material 20 and a second plate material. It is formed from the material which comprises the board | plate material 22, and is provided with the junction part 10 which joins the 1st board | plate material and the 2nd board | plate material. Here, the area | region except the junction part 10 becomes the non-joining part 12 among the 1st board | plate material 20 and the 2nd board | plate material 22. FIG.

  The copper material as the raw material of the first plate material 20 and the second plate material 22 is made of oxygen-free copper. Specifically, the copper material constituting the first plate material 20 and the second plate material 22 is composed of oxygen-free copper having a purity of 99.9% or more (3N or more) and inevitable impurities, and the average crystal grain size is 0. .2 mm or less. The first plate member 20 and the second plate member 22 are joined to each other by friction stir welding (FSW), and are formed by performing a predetermined heat treatment after the FSW joining. Moreover, between the 1st board | plate material 20 and the 2nd board | plate material 22, the area | region where the 1st board | plate material 20 and the 2nd board | plate material 22 were joined and given predetermined heat processing is oxygen-free copper and an unavoidable impurity. It becomes the junction part 10 which consists of.

  Here, the reason why a plate material having an average crystal grain size of 0.2 mm or less is used as a raw material is that, in a plate material having an average crystal grain size exceeding 0.2 mm, fine recrystallized grains and recrystallized after heat treatment after FSW bonding. This is because an oxygen-free copper sputtering target material having a substantially uniform crystal grain structure is difficult to obtain because it tends to be in a mixed-grain state in which particles having a coarse particle diameter remaining without being mixed are mixed.

  In the present embodiment, the first plate material 20 and the second plate material 22 after the FSW bonding and before the heat treatment each take over the average crystal grain size of the copper material as the raw material. And the 1st board | plate material 20 and the 2nd board | plate material 22 after heat processing each have an average crystal grain diameter of 0.04 mm to 0.1 mm as an example. This is because a predetermined heat treatment has a crystal grain size smaller than the crystal grain size constituting the copper material as the raw material in the copper material as the raw material constituting the first plate material 20 and the second plate material 22. This is due to the formation of new recrystallized grains. Specifically, when the average crystal grain size of the copper material as a raw material is fine (for example, an average crystal grain size on the order of several tens of μm), recrystallized grains having an average crystal grain size close to the average crystal grain size of the raw material by recrystallization When the average crystal grain of the copper material as a raw material is coarse (for example, an average crystal grain size of about 100 μm to 200 μm), recrystallized grains finer than the average crystal grain size of the raw material are formed by recrystallization. It is thought to be caused by.

  On the other hand, the joining portion 10 is a region formed by abutting the side surface of the first plate material 20 before heat treatment with the side surface of the second plate material 22 before heat treatment, joining by FSW joining, and then performing heat treatment. It is. That is, the joint portion 10 is formed by plastic deformation of the copper material constituting the first plate material 20 before the heat treatment and the second plate material 22 before the heat treatment so that the average crystal grain size is smaller than the average crystal grain size of the raw material. This is a region formed by subjecting the bonded portion to heat treatment to increase the average crystal grain size of the bonded portion. This coarsening is due to the following reason. That is, the joined portion is heat treated by frictional heat. And the joining part is in the softened state by this frictional heat. When heat treatment is applied to the softened joint portion, recrystallization does not occur in the joint portion, and the average crystal grain size of the joint portion becomes coarse. That is, since the joined portion is in a softened state, new crystal grains are not generated at the crystal grain boundaries or the like (without recrystallization), and the crystal grains are coarsened.

  As an example, the joint 10 after the heat treatment has an average crystal grain size of 0.04 mm to 0.06 mm. That is, when oxygen-free copper plates are joined by FSW joining, the joined portion after FSW joining has a fine average crystal grain size crystal structure with an average crystal grain size of about 0.02 mm to 0.03 mm. Then, by applying a predetermined heat treatment to the joined portion, the joined portion becomes the joined portion 10 having an average crystal grain size of 0.04 mm to 0.06 mm. Therefore, the joint portion 10 formed by performing the heat treatment after the FSW bonding has an average crystal grain size comparable to that of the first plate material 20 and the second plate material 22 after the heat treatment. That is, the joint 10 has a crystal grain structure that is substantially the same as that of the first plate member 20 and the second plate member 22 after the heat treatment.

  In addition, the oxygen-free copper sputtering target material 1 according to the present embodiment is formed in a substantially rectangular shape when viewed from above. And the oxygen-free copper sputtering target material 1 can be formed, for example, having a plane dimension larger than the plane dimension of a glass substrate for display in a liquid crystal display or the like. Moreover, the oxygen-free copper sputtering target material 1 which concerns on this Embodiment can also cut out the shape in the top view of the oxygen-free copper sputtering target material 1 of predetermined shape in a substantially circular shape or a substantially polygonal shape.

(Method for producing oxygen-free copper sputtering target material)
FIG. 2 shows an example of the flow of the manufacturing process of the oxygen-free copper sputtering target material according to the embodiment of the present invention.

  First, an oxygen-free copper having a purity of 99.9% or more is cast and subjected to a predetermined rolling process to produce a plate material having a predetermined dimension (S100). As an example, this plate material has an average crystal grain size of 0.2 mm or less. A plurality of (at least two) plate materials are produced. Next, the side surfaces of the two plates are brought into contact with each other and fixed (S110). Subsequently, a butted portion as a joining portion, which is a portion where the side surface of one plate material and the side surface of the other plate material are abutted, is joined by FSW joining (S120). Thereby, a junction part is formed. In addition, the influence of the FSW bonding on the crystal structure is substantially limited to the bonded portion as the friction stirrer, and the crystal structure before bonding is maintained on one plate member and the other plate member excluding the bonded portion as the non-bonded portion. .

  Next, the front and back surfaces of the joined materials are ground by a predetermined depth (S130). Subsequently, in a vacuum having a predetermined degree of vacuum, there is an annealing effect on oxygen-free copper with respect to one plate material and the other plate material having a joint portion, and the average crystal grain size of oxygen-free copper is Heat treatment is performed at a temperature that is not so coarse (S140). For example, the heat treatment is performed in a vacuum at a temperature range of 400 ° C. to 500 ° C. for a predetermined time. Thereby, a junction part turns into the junction part 10, a non-joint part changes into the non-joint part 12, and the oxygen-free copper sputtering target material 1 which concerns on this Embodiment is manufactured. Note that the grinding step can be performed after the heat treatment step.

  FIG. 3 is a perspective view showing an outline of FSW bonding in the manufacturing process of the oxygen-free copper sputtering target material according to the embodiment of the present invention, and FIG. 4 is an oxygen-free copper sputtering target according to the embodiment of the present invention. It is sectional drawing which shows the outline | summary of the FSW joining in the manufacturing process of material.

  In FSW bonding, a rotary tool 30 having a protrusion 34 having a predetermined shape at the tip is rotated at a predetermined rotation speed in a predetermined direction, and the protrusion 34 of the rotating rotary tool 30 is connected to a plate material 20a as one plate material and the other. The predetermined region of each plate member is softened by the frictional heat generated between the projection 34 and each plate member by being pushed into the portion in contact with the plate member 22a as the plate member, and the predetermined region of each softened plate member is This is a technique of stirring and joining.

  That is, in the present embodiment, as shown in FIG. 3, the rotary tool 30 having the shoulder 32 and the protrusion 34 is rotated in a predetermined direction (for example, the direction “A” in FIG. 3) at a predetermined rotation speed. Meanwhile, the protrusion 34 is inserted to a predetermined depth in the plate material 20a and the plate material 22a as the materials to be joined. Then, the rotary tool 30 is moved relative to the plate material 20 a and the plate material 22 a along the abutting portion 24, and the side surface 20 b of the plate material 20 a and the side surface 22 b of the plate material 22 a are joined along the abutting portion 24. Specifically, the rotary tool 30 is moved at a predetermined speed in the longitudinal direction of the plate material 20a and the plate material 22a (for example, the direction of “B” in FIG. 3).

  Then, as shown in FIG. 4, the plate material 20a and the plate material 22a are in contact with the projections 34 and the projections 34 rotate to generate frictional heat, and the generated frictional heat softens part of the plate material 20a and the plate material 22a, respectively. Then, the friction stirrer 40 becomes fluidized. And when the friction stirring part 40 solidifies, the board | plate material 20a and the board | plate material 22a are joined via the connection part 10b. The portion fluidized by frictional heat is substantially limited to the friction stirrer 40, and the plate material 20a and the plate material 22a are joined in a solid phase, so that the metal structure of the connection portion 10b is refined. That is, the crystal grain structure of the connecting portion 10b is a fine structure having excellent mechanical characteristics as compared with the crystal grain structures of the plate material 20a and the plate material 22a.

  For example, when the plate material 20a made of oxygen-free copper having an average crystal grain size of about 0.2 mm or less and the plate material 22a are joined using FSW joining, the plate material 20a having an average crystal grain size of about 0.02 mm or more and 0.03 mm or less. A connection portion 10b having a crystal grain structure including fine crystal grains having an average crystal grain size smaller than the average crystal grain size of the plate member 22a is obtained. The influence on the crystal structure by the FSW bonding is substantially limited to the friction stirrer 40 as described above.

  Therefore, when the plate material 20a having an average crystal grain size of about 0.2 mm or less and the plate material 22a are joined, the average crystal grain size of the connection portion 10b becomes about 0.02 mm or more and 0.03 mm or less, and the non-joint portion (before the heat treatment ( The average crystal grain size of the plate material 20a and the plate material 22a excluding the joining portion 10b) inherits the average crystal grain size (about 0.2 mm or less) of the plate material 20a and the plate material 22a. Subsequently, by applying a predetermined heat treatment to the material in which the plate member 20a and the plate member 22a are bonded by the bonding portion 10b, the bonding portion 10 formed from the connection portion 10b and the non-bonding portion 12 formed from the non-connection portion Is formed. And the oxygen-free copper sputtering target material 1 which concerns on this Embodiment in which the crystal grain structure of the junction part 10 and the crystal grain structure of the non-joining part 12 are substantially the same grade is obtained.

  As an example, the oxygen-free copper sputtering target material 1 according to the present embodiment can be used for forming an electrode wiring in an electronic component such as a thin film transistor (TFT). For example, the oxygen-free copper sputtering target material 1 can be used for forming electrode wiring in a display panel.

(Effect of embodiment)
The oxygen-free copper sputtering target material 1 according to the present embodiment is formed by friction stir welding a plurality of plate materials made of oxygen-free copper (resistivity: about 2 μΩcm) having a lower resistance than that of an aluminum system (resistivity: about 4 μΩcm). By joining and heat-treating after joining, the difference between the average crystal grain size of the joint 10 and the average crystal grain size of the non-joint 12 can be reduced. That is, the average crystal grain size of the joint portion 10 and the average crystal grain size of the non-joint portion 12 can be made comparable. Therefore, for example, a sputtering target material having an area larger than that of a glass substrate that has been enlarged with an increase in the size of a liquid crystal panel, and the progress of the target erosion between the joining portion 10 and the non-joining portion 12 by sputtering is progressed. The oxygen-free copper sputtering target material 1 capable of reducing the difference and performing stable sputtering can be provided.

  That is, according to the method for manufacturing an oxygen-free copper sputtering target material according to the present embodiment, as an example, an area larger than the size 2200 mm × 2400 mm of the glass substrate for an 8th generation liquid crystal panel (for example, about 3 m square and thick). As an oxygen-free copper sputtering target material 1 having a thickness of 10 mm or more), a large-sized substrate application capable of stable sputtering without substantially causing a difference in the progress of target erosion due to sputtering between a bonded portion and a non-bonded portion. The oxygen-free copper sputtering target material 1 can be provided.

  In this embodiment, oxygen-free copper is used as a raw material for the sputtering target material. The oxygen-free copper has higher conductivity than aluminum, pure copper, and copper added with Zr, Sn, Ag, or the like ( Low electrical resistance). Therefore, the oxygen-free copper sputtering target material 1 according to the present embodiment is advantageous for use as an electrode wiring material, for example.

  The oxygen-free copper sputtering target material according to the example of the present invention was manufactured by employing the following steps. First, oxygen-free copper having a purity of 99.99% was cast. And, four kinds of plate materials of 15mm thickness x width 500mm x length 3000mm are manufactured by performing hot rolling treatment, intermediate heat treatment, and cold rolling treatment on oxygen-free copper obtained by casting. did. Specifically, by appropriately changing the treatment temperature in the intermediate heat treatment and the processing pass schedule in the cold rolling treatment, a plate material A (plate material according to Example 1) having an average crystal grain size of 0.02 mm, and an average crystal Plate material B having a particle size of 0.05 mm (plate material according to Example 2), Plate material C having an average crystal grain size of 0.1 mm (plate material according to Example 3), and plate material having an average crystal grain size of 0.2 mm D (plate material according to Example 4) was manufactured. Here, the average crystal grain size of the plate material was measured by a comparison method between a standard photograph and a plate material photograph based on JIS H0510.

  In addition, as a comparative example, by appropriately changing the processing temperature of the intermediate heat treatment and the processing pass schedule of the cold rolling process, the plate material E (plate material according to comparative example 1) having an average crystal grain size of 0.3 mm and A plate material F (plate material according to Comparative Example 2) having an average crystal grain size of 0.5 mm was produced.

  Next, the plate materials having the same particle diameter, that is, one plate material A and the other plate material A were abutted and fixed on the side surfaces in the longitudinal direction (thus, thickness 15 mm × width 1000 mm × length 3000 mm). ). Subsequently, the butted portion between one plate material A and the other plate material A was joined by FSW joining. Similarly, the plate material B to the plate material D were joined by FSW joining. Thereby, a bonding material was obtained from each of the plate materials according to the example.

  Here, the non-joining portion adjacent to the joint portion where one plate member and the other plate member are joined has the same crystal grain structure as the non-joint portion separated from the joint portion. That is, in each of the joining materials joined by FSW joining from each of the plate materials A to D, the average crystal grain size of the non-joined portion was the same as the average crystal grain size of the plate material before joining. Moreover, in each of the joining materials joined by FSW joining from each of the plate materials A to D, the average crystal grain size of the joining portion between one plate material and the other plate material is a material created from each of the plate materials A to D. In both cases, it was 0.02 mm.

  Moreover, it joined to the board | plate material A which concerns on the Example from the board | plate material D, and joined one board | plate material E and the other board | plate material E by FSW joining, and the joining material which concerns on the comparative example 1 was obtained. Similarly, the bonding material according to Comparative Example 2 was obtained from the plate material F. Here, in each of the joining materials joined by FSW joining from each of the plate material E and the plate material F, the average crystal grain size of the joint portion between one plate material and the other plate material is the plate material A to the plate material D according to the example. Similarly, it was 0.02 mm to 0.03 mm in any of the materials prepared from each of the plate material E and the plate material F. Moreover, also about the average crystal grain diameter of the non-joining part in Comparative Examples 1 and 2, as in Examples 1 to 4, the non-joining part adjacent to the joining part and the non-joining part separated from the joining part are the same. Each having an average crystal grain size identical to the average crystal grain size of the plate material before joining.

  Next, the front and back surfaces of the bonding materials according to Examples (Examples 1 to 4) and Comparative Examples (Comparative Examples 1 and 2) were ground to a depth of 2 mm from the respective surfaces. Subsequently, heat treatment was performed in vacuum at 400 ° C. for 2 hours to each of the bonding materials according to the examples (Examples 1 to 4) and the comparative examples (Comparative Examples 1 and 2). Thus, oxygen-free copper sputtering target materials according to Examples (Examples 1 to 4) and Comparative Examples (Comparative Examples 1 and 2) were prepared.

  Table 1 shows the average crystal grain sizes of the bonded portions and the non-bonded portions before and after the heat treatment of the plate materials and the oxygen-free copper sputtering target materials according to Examples and Comparative Examples of the present invention.

  As can be seen from Table 1, the average crystal grain size of the joint 10 of the oxygen-free copper sputtering target material (that is, the joint material after the heat treatment) according to the example (Examples 1 to 4) is from the plate material A, respectively. Regardless of the average grain size of each of the plate materials D, it was substantially the same from 0.04 mm to 0.06 mm. Further, the average crystal grain size of the non-joined portion 12 of the oxygen-free copper sputtering target material (that is, the joining material after the heat treatment) according to the example (Examples 1 to 4) is 0.04 mm depending on the grain size of the used plate material. From 0.1 mm to 0.1 mm.

  For example, in Example 1, the average crystal grain size of the non-joined portion 12 of the oxygen-free copper sputtering target material formed from the plate A having an average crystal grain size of 0.02 mm was 0.04 mm. Moreover, in Example 2, the average crystal grain size of the non-joint portion 12 of the oxygen-free copper sputtering target material formed from the plate material B having an average crystal grain size of 0.05 mm was 0.06 mm. Moreover, the average crystal grain size of the non-joining part 12 of the oxygen-free copper sputtering target material formed from the plate material C having an average crystal grain size of 0.1 mm was 0.08 mm. Furthermore, the average crystal grain size of the non-joined portion 12 of the oxygen-free copper sputtering target material formed from the plate material D having an average crystal grain size of 0.2 mm was 0.1 mm.

  Here, the average crystal grain size of the joint portion 10 of the oxygen-free copper sputtering target material (that is, the joint material after the heat treatment) according to the comparative example (Comparative Examples 1 and 2) is the same as that in each of Examples 1 to 4. Furthermore, it was substantially the same from 0.05 mm to 0.06 mm. On the other hand, the non-joined portion 12 of the oxygen-free copper sputtering target material (that is, the joining material after the heat treatment) in Comparative Examples 1 and 2 has fine recrystallized grains and coarse crystals close to the original average crystal grain size before joining. It was observed that the mixture was in a mixed grain state.

  Next, each of the oxygen-free copper sputtering target materials according to Examples (Examples 1 to 4) and Comparative Examples (Comparative Examples 1 and 2) was cut out into a circular shape of φ100 mm so as to include the joint portion 10. Thus, while producing the oxygen free copper sputtering target 2 for experiment which concerns on an Example (Examples 1 to 4) from each of the oxygen free copper sputtering target material which concerns on an Example (Examples 1 to 4). From each of the oxygen-free copper sputtering target materials according to Comparative Examples (Comparative Examples 1 and 2), experimental oxygen-free copper sputtering targets according to Comparative Examples (Comparative Examples 1 and 2) were prepared.

  FIG. 5 shows a top view after sputtering of an experimental oxygen-free copper sputtering target according to an embodiment of the present invention.

  Sputtering was performed using the oxygen-free copper sputtering target for experiments according to Examples (Examples 1 to 4) and Comparative Examples (Comparative Examples 1 and 2). A magnetron sputtering apparatus was used as the sputtering apparatus. The sputtering conditions are as follows. That is, argon (Ar) gas having a pressure of 1 Pa was used as the introduced gas, the RF power was set to 300 W, and the cumulative time of the sputtering process was 180 minutes.

  As a result of sputtering, an erosion (erosion) region 50 recessed in a ring shape was formed on the surface of the oxygen-free copper sputtering target after sputtering as shown in FIG.

  In the experimental oxygen-free copper sputtering target 2 according to Examples 1 to 4, no change in erosion at the boundary between the bonded portion 10a and the non-bonded portion 12a was visually observed. Further, in the experimental oxygen-free copper sputtering target 2 according to Examples 1 to 4, there was substantially no difference in the progress of erosion at the boundary between the bonded portion 10a and the non-bonded portion 12a.

  On the other hand, in the oxygen-free copper sputtering target for experiments according to Comparative Examples 1 and 2, the boundary between the bonded portion and the non-bonded portion is conspicuous on the surface of the oxygen-free copper sputtering target after sputtering. It was recognized that there was a considerable difference in the progress of erosion.

  Further, for each of the oxygen-free copper sputtering targets according to the examples (Examples 1 to 4) and the comparative examples (Comparative Examples 1 and 2), the difference in the sputtering situation between the bonded portion 10a and the non-bonded portion 12a is quantitatively determined. The surface roughness of each of the erosion region of the joint portion 10a and the erosion region of the non-joint portion 12a was measured. As for the surface roughness, arithmetic average roughness (Ra) was measured based on JIS B0601. The unit of arithmetic average roughness is μm. Here, the ring width of the erosion region 50 was observed to be about 20 mm, and the surface roughness was measured for a length of 3 mm near the center of the width. Specifically, for each of the portion corresponding to the erosion region 50 of the bonded portion 10a (surface roughness measuring portion 54) and the portion corresponding to the erosion region 50 of the non-bonded portion 12a (surface roughness measuring portion 52), The surface roughness was measured.

  Table 2 shows the measurement results of the surface roughness according to Examples and Comparative Examples of the present invention.

  Referring to Table 2, in the experimental oxygen-free copper sputtering target material according to Comparative Example 1, the difference in surface roughness between the bonded portion 10a and the non-bonded portion 12a is -34%. In the experimental oxygen-free copper sputtering target material, the difference in surface roughness between the bonded portion 10a and the non-bonded portion 12a was -36%. On the other hand, in the experimental oxygen-free copper sputtering target material according to Examples 1 to 4, the difference in surface roughness between the bonded portion 10a and the non-bonded portion 12a is within ± 7% to 8%. It was observed that there was.

  From this result, in the oxygen-free copper sputtering target material according to Examples 1 to 4, there is no significant difference in the degree of progress of erosion between the bonded portion 10a and the non-bonded portion 12a. It was shown that more stable sputtering can be carried out than the oxygen-free copper sputtering target. That is, in the oxygen-free copper sputtering target according to Comparative Examples 1 and 2, the sputtering is unstable and affects the uniformity of the copper film formed by sputtering, while the oxygen-free copper sputtering according to Examples 1 to 4 According to the target 2, it was shown that stable sputtering can be performed.

  While the embodiments and examples of the present invention have been described above, the embodiments and examples described above do not limit the invention according to the claims. It should be noted that not all combinations of features described in the embodiments and examples are necessarily essential to the means for solving the problems of the invention.

It is a fragmentary perspective view of the oxygen-free copper sputtering target material which concerns on embodiment. It is a figure which shows the flow of the manufacturing process of the oxygen-free copper sputtering target material which concerns on embodiment. It is a perspective view which shows the outline | summary of the FSW joining in the manufacturing process of the oxygen-free copper sputtering target material which concerns on embodiment. It is sectional drawing which shows the outline | summary of the FSW joining in the manufacturing process of the oxygen-free copper sputtering target material which concerns on embodiment. It is a top view after sputtering of the experimental oxygen-free copper sputtering target according to the example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oxygen-free copper sputtering target material 2 Oxygen-free copper sputtering target 10, 10a Joining part 10b Connection part 12, 12a Non-joining part 20 1st board | plate material 20a, 22a Board | plate material 20b, 22b Side surface 22 2nd board | plate material 24 Butt | matching part 30 rotation Tool 32 Shoulder 34 Protrusion 40 Friction stirrer 50 Erosion region 52, 54 Surface roughness measurement part

Claims (5)

A first plate material and a second plate material which are formed from a copper material made of oxygen-free copper having a purity of 3N or more, and whose average crystal grain size is 0.04 mm or more and 0.1 mm or less;
Between the first plate member and the second plate member, a joining portion formed from the first plate member and the second plate member and having an average crystal grain size of 0.04 mm or more and 0.06 mm or less. Oxygen free copper sputtering target material.   The oxygen-free copper sputtering target material according to claim 1, wherein the oxygen-free copper sputtering target material has a plane dimension larger than that in a top view of a glass substrate for a display panel. A plate material preparation step of preparing a plurality of plate materials made of copper material composed of oxygen-free copper;
A butting step of abutting the side surface of one plate member and the side surface of the other plate member of the plurality of plate members;
A joining step of joining a butted portion formed by abutting a side surface of the one plate material and a side surface of the other plate material by friction stir welding to form a joined portion;
The joint portion and the one plate member and the other plate member joined to each other by the joint portion are subjected to a heat treatment in a vacuum to coarsen crystals of the joint portion, and the one plate member and the other plate member. A method for producing an oxygen-free copper sputtering target material, comprising: a heat treatment step of generating recrystallized grains in a non-joined portion that is a portion obtained by removing the joined portion from a plate material. The plate material preparation step prepares the plurality of plate materials having an average crystal grain size of 0.2 mm or less,
The said joining process is a manufacturing method of the oxygen-free copper sputtering target material of Claim 3 which forms the said junction part whose average crystal grain diameter is 0.02 mm or more and 0.03 mm or less. The heat treatment step forms a joined portion having an average crystal grain size of 0.04 mm or more and 0.06 mm or less from the joined portion and a non-joined portion having an average crystal grain size of 0.04 mm or more and 0.1 mm or less. The manufacturing method of the oxygen-free copper sputtering target material of Claim 3 or 4 which forms a junction part.

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