JP5233485B2 - Oxygen-free copper sputtering target material and method for producing oxygen-free copper sputtering target material - Google Patents

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). Pure copper is also used as a raw material for the sputtering target material described in 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, in the sputtering target material according to Patent Document 1, the joint between the metal plate and the metal plate has a different crystal structure from the portion other than the joint, and it may be insufficient in terms of uniform sputtering. is there. In particular, an increase in the size of the sputtering target material is required in accordance with an increase in the size of the display panel, which may be a problem when a large-sized sputtering target material is manufactured by joining metal plates of a predetermined size.

  Accordingly, an object of the present invention is to produce a large-sized oxygen-free copper sputtering target material and an oxygen-free copper sputtering target material that can form a film on a large substrate, can cope with a reduction in electrical resistance of electrode wiring, and can perform uniform sputtering. It is to provide a method.

In order to achieve the above object, the present invention provides a first plate member made of oxygen-free copper having a purity of 3N or more, a second plate member made of the same material as the first plate member, a first plate member, and a second plate member. Between the first plate member and the second plate member, and the average particle size of the first plate member and the second plate member is 0.02 mm or more and 0.04 mm or less. the oxygen-free copper sputtering target material average grain size flat is 0.02mm is provided.

  The oxygen-free copper sputtering target material can also be formed with a plane dimension larger than that in a top view of a glass substrate for a display panel.

The present invention, in order to achieve the above object, Ri Do of oxygen-free copper, and a first plate and first plate of the same material average particle size of less 0.04mm or 0.02mm The plate material preparation step for preparing the second plate material, the butting step for matching the side surface of the first plate material and the side surface of the second plate material, and the side surface of the first plate material and the side surface of the second plate material are butted together. abut portion and a bonding step of bonding to form a joint by friction stir welding, bonding process, the manufacturing method of the oxygen-free copper sputtering target material average grain size to form a joint which is 0.02mm Is provided.

  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, a large size that can form a film on a large substrate, can cope with a reduction in electrical resistance of electrode wiring, and can perform uniform sputtering. The oxygen-free copper sputtering target material and the method for producing the 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. A joining portion 10 formed of the plate material 22 and joining the first plate material and the second plate material is provided. 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, each of the first plate member 20 and the second plate member 22 is formed of a copper material as a raw material made of oxygen-free copper having a purity of 99.9% or more and unavoidable impurities. Here, the first plate member 20 and the second plate member 22 are joined to each other by friction stir welding (FSW). And between the 1st board | plate material 20 and the 2nd board | plate material 22, the joining area | region (joining part) where the 1st board | plate material 20 and the 2nd board | plate material 22 were joined consists of oxygen-free copper and an unavoidable impurity. It becomes the junction 10.

  In the present embodiment, the first plate member 20 and the second plate member 22 each inherit the average crystal grain size of the copper material. Therefore, the average crystal grain size of the non-joined portion 12 inherits the average crystal grain size of the copper material as the raw material of the first plate member 20 and the second plate member 22. On the other hand, the joint portion 10 is an area formed by FSW joining by abutting the side surface of the first plate material 20 and the side surface of the second plate material 22, and constitutes the first plate material 20 and the second plate material 22. This is an area formed by plastic deformation of a copper material. Therefore, the joint portion 10 is formed including crystal grains having an average crystal grain size of about 0.02 mm by FSW joining.

  Here, in the present embodiment, a predetermined average crystal grain size is set so that the crystal structure of the first plate member 20 and the second plate member 22 and the crystal structure of the joint 10 are substantially the same. The copper material is produced and used as the raw material for the first plate material 20 and the second plate material 22. Specifically, an average crystal grain that is substantially the same as the average crystal grain size of the joining portion that occurs when copper materials made of copper plates having a predetermined grain size and a predetermined classification are joined by FSW joining. A copper material having a diameter is used as a raw material for the first plate material 20 and the second plate material 22. As a result, the difference between the average crystal grain size of the first plate member 20 and the second plate member 22 and the average crystal grain size of the joint 10 falls within a predetermined range and is substantially the same (or substantially To the same).

  For example, the oxygen-free copper sputtering target material 1 according to the present embodiment has a non-joint portion 12 (the first plate material 20 and the first plate material 20) formed of a copper material having an average crystal grain size of 0.02 mm to 0.04 mm. 2 and a part of the first plate member 20 and a part of the second plate member 22 by FSW bonding, and the average crystal grain size is 0.02 mm or more and 0.03 mm. The following joint portions 10 are provided. That is, in the oxygen-free copper sputtering target material 1 according to the present embodiment, the average crystal grain size of the non-joint portion 12 and the average crystal grain size of the joint portion 10 are approximately the same.

  In addition, the oxygen-free copper sputtering target material 1 according to the present embodiment is formed in a substantially rectangular shape (as an example, 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. In addition, the oxygen-free copper sputtering target material 1 according to the present embodiment can be formed so that the shape in the top view is substantially circular or substantially polygonal.

(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). A plurality of (at least two) plate materials are produced. Next, the side surfaces of the two plate members as the first plate member 20 and the second plate member 22 are abutted and fixed to each other (S110). Subsequently, a butted portion, which is a portion where the side surface of the first plate member 20 and the side surface of the second plate member 22 are butted, is joined by FSW joining (S120). Thereby, the joining material in which the joining part 10 in which the difference with the average crystal grain diameter of the 1st board | plate material 20 and the 2nd board | plate material 22 has an average crystal grain diameter in a predetermined range was formed is obtained. Next, the front and back surfaces of the bonding material are ground by a predetermined depth (S130). Thereby, the oxygen free copper sputtering target material 1 which concerns on this Embodiment is manufactured.

  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 with a predetermined shape at the tip is rotated in a predetermined direction at a predetermined rotation speed, and the protrusion 34 of the rotating rotary tool 30 is connected between one plate material and the other plate material. This is a technique in which a predetermined region of each plate member is softened by frictional heat generated between the protrusion 34 and each plate member by being pushed into the joining portion, and the predetermined region of each softened plate member is stirred and joined.

  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 protrusions 34 are inserted to a predetermined depth in the first plate member 20 and the second plate member 22 as the materials to be joined. Then, the rotary tool 30 is moved relative to the first plate member 20 and the second plate member 22 along the boundary where the first plate member 20 and the second plate member 22 are in contact, that is, along the abutting portion 24. Then, the side surface 20 a of the first plate member 20 and the side surface 22 a of the second plate member 22 are joined along the abutting portion 24. As an example, the rotary tool 30 is moved at a predetermined speed in the longitudinal direction of the first plate member 20 and the second plate member 22 (for example, the direction of “B” in FIG. 3).

  Then, as shown in FIG. 4, the first plate member 20 and the second plate member 22 are in contact with the projections 34 and the projections 34 are rotated to generate frictional heat, and the generated frictional heat causes the first plate member 20. And a part of 2nd board | plate material 22 each softens, becomes the friction stirring part 40, and fluidizes. Then, when the friction stirrer 40 is solidified, the first plate member 20 and the second plate member 22 are joined via the joint 10. The portion fluidized by frictional heat is substantially limited to the friction stirrer 40, and the first plate member 20 and the second plate member 22 are joined in a solid phase.

  For example, when the first plate member 20 and the second plate member 22 made of oxygen-free copper having an average crystal grain size of 0.02 mm or more and 0.04 mm or less are joined using FSW joining, the average crystal grain size becomes 0.1. A joint 10 having a crystal grain structure having a fine crystal grain size of about 02 mm to 0.03 mm is formed. The influence on the crystal structure by the FSW bonding is substantially limited to the friction stirrer 40 as described above.

  Therefore, when the first plate member 20 and the second plate member 22 having an average crystal grain size of 0.02 mm to 0.04 mm are joined, the average crystal grain size of the joint 10 is 0.02 mm to 0.03 mm. The average crystal grain size of the non-joined portion 12 (the portion excluding the joined portion 10 from the first plate material 20 and the second plate material 22) is the average crystal grain size of the first plate material 20 and the second plate material 22. The diameter (about 0.02 mm or more and 0.04 mm or less) will be inherited. As a result, the oxygen-free copper sputtering target material 1 according to the present embodiment in which the crystal grain structure is the same at the joint 10 and the non-joint 12 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 a plurality of plate materials made of oxygen-free copper (resistivity: about 2 μΩcm) having a purity of 3N or higher and lower resistance than that of an aluminum system (resistance: about 4 μΩcm). Can be joined by friction stir welding so that the average crystal grain size of the joined portion and the average crystal grain size of the non-joined portion can be made substantially the same . The difference between the average crystal grain size of the average grain size and a non-joint portion 12 of the junction 10 can be reduced. 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.

  Further, in the production of the oxygen-free copper sputtering target material 1 according to the present embodiment, since one plate material and the other plate material are FSW bonded, it is not necessary to heat-treat the bonded plate material. Large equipment for heat-treating the target material at a uniform temperature (for example, a large furnace corresponding to the large target material, a large rolling mill, etc.) becomes unnecessary.

  Further, in this embodiment, oxygen-free copper is used as a raw material for the sputtering target material, and oxygen-free copper has conductivity (low electrical resistance) that is equal to or higher than that of pure copper. Therefore, the oxygen-free copper sputtering target material 1 according to the present embodiment is advantageous for use as a wiring material for thin wire electrodes, 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. The oxygen-free copper obtained by casting is subjected to hot rolling treatment, intermediate heat treatment, and cold rolling treatment to obtain a thickness of 15 mm × width of 500 mm × length of 3000 mm, and an average crystal grain size ( A plate material A having a particle size before bonding (0.02 mm) and a plate material B having an average crystal particle size (particle size before bonding) of 0.04 mm were 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.

  Further, as a comparative example, by appropriately changing the treatment temperature of the intermediate heat treatment and the processing pass schedule of the cold rolling treatment, the plate material C having an average crystal grain size (grain size before joining) of 0.05 mm and the average A plate material D having a crystal grain size (particle size before bonding) of 0.1 mm, a plate material E having an average crystal particle size (particle size before bonding) of 0.2 mm, and an average crystal particle size (particle size before bonding) of 0.1 mm. A plate material F of 3 mm and a plate material G having an average crystal grain size (particle size before joining) of 0.5 mm were 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. Thereby, the oxygen-free copper sputtering target material which concerns on Example 1 was obtained. Similarly, the oxygen-free copper sputtering target material according to Example 2 was obtained by joining one plate material B and the other plate material B by FSW bonding.

  Moreover, it carried out similarly to Example 1 and Example 2, and obtained the oxygen free copper sputtering target material which concerns on the comparative example 1 by joining one board | plate material C and the other board | plate material C by FSW joining. Similarly, oxygen-free copper sputtering materials according to Comparative Example 2 to Comparative Example 5 were obtained from each of the plate material D to the plate material G.

  Table 1 shows the measurement results of the crystal grain size before and after bonding of the oxygen-free copper sputtering target materials according to the examples and comparative examples of the present invention.

  Referring to Table 1, the average crystal grain size of the joint formed by FSW joining the butt portion between one plate material A and the other plate material A, and the butt portion between one plate material B and the other plate material B. The average crystal grain size of the joint formed by FSW joining was 0.02 mm, respectively. That is, it was shown that the average crystal grain size of the joint is the same as the average crystal grain size of the plate material as the raw material or is equal to or less than the average crystal grain size of the plate material as the raw material. In addition, in both the oxygen-free copper sputtering target material according to Example 1 and the oxygen-free copper sputtering target material according to Example 2, the non-joined part adjacent to the joined part is the average crystal grain size of the plate material before joining. They had the same average grain size. That is, the non-joining part adjacent to the joining part of the oxygen-free copper sputtering target material according to Example 1 and Example 2 had the same crystal grain structure as the non-joining part separated from the joining part.

  On the other hand, in the oxygen-free copper sputtering materials according to Comparative Examples 1 to 5, the average crystal grain size of the joint portion was 0.02 mm to 0.03 mm, as in Examples 1 and 2. And also about the average crystal grain diameter of a non-joining part, as in Example 1 and Example 2, all of the oxygen-free copper sputtering materials according to Comparative Examples 1 to 5 are adjacent to the joining part, The average crystal grain size was the same as the average crystal grain size of the plate material before joining. That is, for each of the oxygen-free copper sputtering materials according to Comparative Examples 1 to 5, the non-joining part adjacent to the joining part had the same crystal grain structure as the non-joining part separated from the joining part. This shows that the non-joining part has inherited the crystal grain structure of the plate material as a raw material.

  Next, the front and back surfaces of the oxygen-free copper sputtering target materials according to Example 1 and Example 2 and Comparative Examples 1 to 5 were ground to a depth of 2 mm from each surface. Subsequently, each of the oxygen-free copper sputtering target materials according to Example 1 and Example 2 and Comparative Examples 1 to 5 was cut out into a circular shape of φ100 mm so as to include a joint portion. Thus, while producing the oxygen free copper sputtering target 2 for an experiment from each of the oxygen free copper sputtering target material which concerns on Example 1 and Example 2, the oxygen free copper sputtering target which concerns on Comparative Examples 1-5 is produced. An experimental oxygen-free copper sputtering target was created from each of the materials.

  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 carried out using the oxygen-free copper sputtering target for experiments according to Examples (Examples 1 and 2) and Comparative Examples (Comparative Examples 1 to 5). 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 oxygen-free copper sputtering target 2 according to Example 1 and Example 2, no change in erosion at the boundary between the bonded portion 10a and the non-bonded portion 12a was visually observed. Furthermore, in the oxygen-free copper sputtering target 2 according to Example 1 and Example 2, substantially no difference was observed 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 according to Comparative Examples 1 to 5, 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, and erosion progresses in each portion. It was recognized that there was a considerable difference in

  Moreover, about each of the oxygen-free copper sputtering target which concerns on an Example (Example 1 and Example 2) and a comparative example (Comparative Examples 1-5), the difference in the sputtering condition in the junction part 10a and the non-joint part 12a is shown. For the purpose of examining quantitatively, 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, the difference in surface roughness between the bonded portion 10a and the non-bonded portion 12a was 3% in Example 1 and 8% in Example 2. On the other hand, in Comparative Examples 1 to 5, as the difference between the particle size of the bonded portion 10a and the particle size of the non-bonded portion 12a increases, the difference between the surface roughness of the bonded portion 10a and the surface roughness of the non-bonded portion 12a differs. Increased. For example, in Comparative Example 1 (the average crystal grain size of the joint 10a is 0.02 mm and the average crystal grain size of the non-joint 12a is 0.05 mm), the surface roughness between the joint 10a and the non-joint 12a. The difference is 13%, and in Comparative Example 5 (the average crystal grain size of the joint 10a is 0.03 mm and the average crystal grain size of the non-joint 12a is 0.5 mm), the joint 10a and the non-joint 12a The difference in surface roughness between the two was as great as 80%.

  From the above results, sputtering is unstable in the oxygen-free copper sputtering targets according to Comparative Examples 1 to 5, and the uniformity of the copper film formed by sputtering is affected. According to the oxygen-free copper sputtering target 2, it was shown that stable sputtering can be obtained.

  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 12, 12a Non-joining part 20 1st board | plate material 20a, 22a Side surface 22 2nd board | plate material 24 Butt part 30 Rotating tool 32 Shoulder 34 Protrusion 40 Friction Stirring section 50 Erosion area 52, 54 Surface roughness measurement section

Claims (3)

A first plate made of oxygen-free copper having a purity of 3N or more, and a second plate made of the same material as the first plate,
A bonding portion formed from the first plate member and the second plate member between the first plate member and the second plate member;
Said first plate and said second average particle size of the plate is less 0.04mm or 0.02 mm, pre-Symbol oxygen-free copper sputtering target material with a joint that average grain diameter 0.02 mm.   The oxygen-free copper sputtering target material according to claim 1, wherein the oxygen-free copper sputtering target material has a planar dimension larger than a planar dimension in a top view of a glass substrate for a display panel. Ri Do of oxygen-free copper, the plate preparation step of preparing a second plate member composed of the first plate and the first plate of the same material is equal to or less than the average particle diameter is more than 0.02 mm 0.04 mm,
A butting step of abutting the side surface of the first plate member and the side surface of the second plate member;
A joining step of joining the butted portion where the side surface of the first plate material and the side surface of the second plate material are butted together by friction stir welding to form a joint portion;
The joining step, the manufacturing method of oxygen-free copper sputtering target material average grain size to form the joint is 0.02 mm.

Images