WO2011099426A1 - Pure copper plate production method, and pure copper plate - Google Patents

Abstract

Disclosed is a pure copper plate production method wherein post-hot-forging and post-hot-rolling cold forging and cold rolling, and subsequent heat processing are unnecessary. Further disclosed is a pure copper plate having a fine structure which is obtained according to the disclosed production method and which is provided with a high special grain boundary ratio due to the formation of a twin crystal structure by means of partial recrystalisation, and is particularly suitable for copper target members for sputtering, or anodes for plating, or similar. A pure copper ingot having a purity level of 99.96 weight% or higher is heated to 550-800˚C. A hot-rolling process is carried out wherein the total rolling rate is 85% or higher, the temperature at rolling completion is 500-700˚C, and which includes at least one finishing rolling pass having a rolling reduction rate for one pass of 5-24%. Then, rapid cooling from the rolling completion temperature to 200˚C or lower is carried out at a cooling speed of 200-1000˚C/min, as required.

Description

Pure copper plate manufacturing method and pure copper plate

The present invention relates to a method for producing a pure copper plate having good quality, and more particularly, a pure copper plate having a fine structure and a high special grain boundary ratio by forming a twin structure by partial recrystallization. And a pure copper plate suitable for a sputtering copper target material, an anode material for plating, and the like manufactured by the manufacturing method.
This application claims priority based on Japanese Patent Application No. 2010-26455 for which it applied on February 9, 2010, and uses the content here.

A pure copper plate is usually manufactured by hot rolling or hot forging a pure copper ingot, followed by cold rolling or cold forging, and then heat treatment for strain relief or recrystallization. Such a pure copper plate is used after being processed into a desired shape by saw cutting, cutting, embossing, cold forging, etc. In order to reduce stuffiness and deformation during processing, the crystal grain size Is small and the residual stress in the crystal structure is required to be small.

Moreover, the pure copper plate manufactured by the above-described method has recently been used as a sputtering target for wiring material of semiconductor elements. Al (specific resistance of about 3.1 μΩ · cm) has been used as a wiring material for semiconductor elements, but with the recent miniaturization of wiring, copper wiring with lower resistance (specific resistance of about 1.7 μΩ · cm) is used. It has been put into practical use. As a process for forming this copper wiring, a diffusion barrier layer such as Ta / TaN is formed in a concave portion of a contact hole or wiring groove, and then copper is electroplated in many cases. As a layer), pure copper is sputter-deposited.

Normally, 5N (purity 99.999% or higher) to 6N (purity 99.9999%) is obtained by wet or dry high-purification process using 4N (purity 99.99% or higher: without gas components) as a crude metal. % Or more) is produced, and this is used as a pure copper plate by the above-described method, and is further used as a sputtering target after being processed into a desired shape. In order to produce a sputtered film with low electrical resistance, the impurity content in the sputtering target must be kept below a certain value, and the elements added for alloying must also be lowered below a certain level. In order to obtain this uniformity, it is necessary to suppress variations in the crystal grain size and crystal orientation of the sputtering target.

As a conventional method for industrially producing such a pure copper target for sputtering, in Patent Document 1, a pure copper ingot having a purity of 99.995 wt% or more is hot-worked, and then annealed at a temperature of 900 ° C. or less. Next, after performing cold rolling at a rolling rate of 40% or more, recrystallization annealing is performed at a temperature of 500 ° C. or less, so that it has a substantially recrystallized structure and an average crystal grain size of 80 microns or less. A method for obtaining a sputtering copper target having a Vickers hardness of 100 or less is disclosed.

Further, in Patent Document 2, a high purity copper ingot of 5N or more is subjected to hot working with a working rate of 50% or more such as hot forging or hot rolling, and then further cold rolling or cold forging or the like. By performing cold working at a working rate of 30% or more and performing heat treatment at 350 to 500 ° C. for 1 to 2 hours, each of Na and K contents is 0.1 ppm or less, Fe, Ni, Cr, Al, The Ca and Mg contents are each 1 ppm or less, the carbon and oxygen contents are each 5 ppm or less, the U and Th contents are each 1 ppb or less, and the copper content excluding gas components is 99.999% or more, The average particle size on the sputtering surface is 250 μm or less, the variation in average particle size is within ± 20%, and the X-ray diffraction intensity ratio I (111) / I (200) is 2.4 or more on the sputtering surface, and the variation is ± 20. How to obtain the sputtering copper target is within is disclosed.

Further, in Patent Document 3, the surface layer of an ingot made of high purity copper having a purity of 6N or more and an additive element was removed, and the product was obtained through hot forging, hot rolling, cold rolling, and a heat treatment process. Copper alloy sputtering target containing 0.5 to 4.0 wt% Al and 0.5 wtppm or less of Si, sputtering copper alloy containing 0.5 to 4.0 wt% of Sn and 0.5 wtppm or less of Mn A target and a copper alloy sputtering target containing one or more selected from Sb, Zr, Ti, Cr, Ag, Au, Cd, In, and As in a total amount of 1.0 wtppm or less are disclosed. In particular, in the examples, after removing the surface layer of the manufactured ingot to φ160 mm × thickness 60 mm, hot forging at 400 ° C. to φ200 mm, and then hot rolling at 400 ° C. to φ270 mm × There is a description of rolling to a thickness of 20 mm, further rolling by cold rolling to φ360 mm × thickness of 10 mm, heat-treating at 500 ° C. for 1 hour, and then rapidly cooling the entire target to obtain a target material.

As represented by such a method for producing a copper target for sputtering, in a conventional method for producing a pure copper plate, a pure copper ingot was subjected to hot forging or hot rolling in order to obtain a homogeneous and stable recrystallized structure. Thereafter, cold forging and cold rolling are performed, and further heat treatment is performed.

Japanese Patent Laid-Open No. 11-158614 JP-A-10-330923 JP 2009-114539 A

In the conventional method of industrially producing a pure copper plate having a large and uniform homogeneous and stable crystal structure, after hot forging or hot rolling is performed on a pure copper ingot, further cold forging or cold rolling, Although it is necessary to perform heat treatment, it is possible to suppress abnormal discharge due to high-power sputtering in the sputtering target, improve homogeneous solubility in the anode for plating, and heat-resistant fatigue characteristics in the heat dissipation substrate by only miniaturization. Has become difficult.

The present invention has been made in view of such circumstances, and a method for producing a pure copper plate that does not require cold forging, cold rolling, and subsequent heat treatment after hot forging or hot rolling, and , A copper plate having a fine structure obtained by the manufacturing method, and having a high special grain boundary ratio by forming a twin structure by partial recrystallization, in particular, a copper target material for sputtering, an anode for plating, etc. Provide suitable pure copper plate.

As a result of diligent study, the inventors of the present invention have promoted recrystallization in a pure copper ingot after hot forging or hot rolling, cold forging or cold rolling, and subsequent heat treatment, thereby achieving fine and homogeneous crystals. Without relying on conventional methods of obtaining grains, pure copper ingots are hot-rolled under certain conditions to suppress grain growth, promote the formation of twin structures by partial recrystallization, and It was found that a pure copper plate having a finer metal structure with a high special grain boundary ratio can be produced by quenching under certain conditions to stop grain growth as required.

In the method for producing a pure copper plate of the present invention, a pure copper ingot having a purity of 99.96 wt% or more is heated to 550 ° C. to 800 ° C., the total rolling rate is 85% or more, and the temperature at the end of rolling is 500 to 700. And a hot rolling process having one or more finishing hot rollings at 5 ° C. and a rolling reduction per pass of 5 to 24%. If necessary, from the temperature at the end of rolling to 200 ° C. It is characterized by rapid cooling at a cooling rate of 200 to 1000 ° C./min until a temperature of not higher than ° C.

In order to obtain a microstructure with a fine grain boundary ratio and increased special grain boundary ratio by promoting the formation of a twin structure by partial recrystallization, the temperature at the final hot rolling, which is the final step of hot rolling, is used. The rolling reduction per pass in the finish hot rolling is important (hereinafter referred to as the rolling end temperature). In finish hot rolling, when the rolling end temperature is less than 500 ° C. or the rolling reduction per pass is less than 5%, partial recrystallization does not occur sufficiently, and the rolling end temperature is 700 ° C. If it exceeds or the rolling reduction per pass is 25% or more, dynamic recrystallization becomes dominant during finish hot rolling, and high special grain boundaries accompanying the formation of twin structure by partial recrystallization. It becomes difficult to obtain a ratio. In order to set the rolling end temperature to 500 to 700 ° C., the hot rolling start temperature is preferably 550 to 800 ° C.

Moreover, it is good to set it as 85% or more as a total rolling rate by this hot rolling, and suppressing the coarsening of the diameter of a crystal grain and making the variation small by making a total rolling rate into 85% or more. it can. If the total rolling ratio is less than 85%, the crystal grain size tends to increase and the variation thereof increases.
In addition, by forming the reduction ratio per pass in the finish hot rolling in the hot rolling at 5 to 24%, the formation of twin structure is promoted and the special grain boundary ratio is increased and the grain boundaries are matched. And the crystal structure becomes fine and uniform. Further, in the above finish hot rolling, the rolling reduction per pass may be 5 to 24% in the range of 500 to 700 ° C., and at least one pass rolling may be performed. Good. In particular, the formation of the twin structure is further promoted by carrying out the multiple pass repeated rolling. The pure copper plate manufactured in this way is effective for uses such as a sputtering target, an anode for plating, and a heat dissipation substrate.

Then, after such hot rolling is completed, quenching may be performed at a cooling rate of 200 to 1000 ° C./min until a temperature of 200 ° C. or lower is reached. If the cooling rate is less than 200 ° C./min, the effect of suppressing the growth of crystal grains is poor, and even if it exceeds 1000 ° C./min, it does not contribute to the effect of suppressing further grain growth. A more preferable cooling rate is in the range of 300 to 600 ° C./min.
If it is cooled to a temperature of 200 ° C. or less at a cooling rate in such a range, the growth of crystal grains can be stopped to obtain fine crystal grains. On the other hand, if the rapid cooling is stopped at a temperature exceeding 200 ° C., the crystal grains may gradually grow by being left in the high temperature state.

In addition, the pure copper plate manufactured by the manufacturing method of the present invention has a ratio of the total special grain boundary length Lσ of the special grain boundary to the total grain boundary length L of the crystal grain boundary measured by the EBSD method (Lσ / L). Is 55% or more.
When the frequency of the special grain boundary is higher than 55%, the consistency of the crystal grain boundary is improved, and various characteristics such as sputtering characteristics of the sputtering target, solubility in the anode for plating, and deformation characteristics of the plate material are improved. Become.

The pure copper plate of the present invention is suitable for use as a sputtering target.
In particular, by having a high special grain boundary ratio by forming a twin structure by partial recrystallization, the occurrence of abnormal discharge can be suppressed even in sputtering under high output.

According to the present invention, a pure copper plate suitable for a sputtering copper target material having fine and uniform crystal grains and hardly causing abnormal discharge under high output, or an anode material for plating exhibiting uniform solubility is manufactured. can do.

It is a microscope picture of the mushy produced when the surface of a pure copper plate is cut.

Hereinafter, embodiments of the present invention will be described.
The pure copper plate of this embodiment is oxygen-free copper having a copper purity of 99.96 wt% or more, or oxygen-free copper for electron tubes having 99.99 wt% or more.
The average grain size determined by the EBSD method is 10 to 200 μm, more preferably 80 μm, and the total special grain boundary length of the special grain boundary with respect to the total grain boundary length L of the grain boundary measured by the EBSD method. The ratio of Lσ (Lσ / L) is 55% or more.

Further, when large crystal grains having a grain size exceeding 200 μm are mixed, fine spilling tends to occur on the surface in the cutting process. As shown in FIG. 3, this mussel is denoted by C in the direction perpendicular to the cutting direction in the cutting mark W generated in the cutting direction (direction indicated by the arrow A) when the material is cut by a milling machine or the like. As shown by, the fine irregularities generated in a streak shape. When this mess is generated, the appearance of the product is impaired.
Setting the average crystal grain size to less than 10 μm is not realistic and causes an increase in manufacturing cost.

In addition, by setting the length ratio of the special grain boundary to 55% or more, the consistency of the crystal grain boundary is improved, which is effective for applications such as a sputtering target, an anode for plating, and a heat dissipation substrate.
A crystal grain boundary is defined as a boundary between crystals when the orientation between two adjacent crystals is 15 ° or more as a result of two-dimensional cross-sectional observation. A special grain boundary is a crystal grain having a crystal value of 3 ≦ Σ ≦ 29 with a Σ value defined crystallographically based on CSL theory (Kronberg et.al .: Trans. Met. Soc. AIME, 185, 501 (1949)). Grain which is a boundary (corresponding grain boundary) and has an inherent corresponding site lattice orientation defect Dq at the grain boundary satisfying Dq ≦ 15 ° / Σ ^1/2 (DGBrandon: Acta. Metallurgica. Vol.14, p1479, 1966) Defined as a bound.
If the length ratio of this special grain boundary is high among all crystal grain boundaries, the consistency of the crystal grain boundaries is improved, and sputtering targets, plating anodes, heat dissipation substrates, etc. that are widely known as pure copper plate applications The characteristics can be improved.

That is, in the sputtering target, it is said that there is a correlation between the abnormal discharge characteristics during sputtering and the crystal structure, and the purity of the material is reduced, that is, the content of impurities is reduced (Japanese Patent Laid-Open No. 2002-129313). Means for suppressing abnormal discharge among the sputter characteristics are shown by homogeneity (WO03 / 046250), control of crystal orientation of the structure (Japanese Patent Laid-Open No. 10-330923), and the like. However, in recent years, a further improvement in the sputtering rate has been demanded in order to improve productivity, and the sputtering voltage tends to increase. When the sputtering voltage is improved, an abnormal discharge is more likely to occur during sputtering. Therefore, the conventional structure control method alone is not sufficient for suppressing abnormal discharge, and further structure control is required.

In addition, the anode material for plating made of pure copper is used especially for through-hole plating of printed wiring boards, but when the anode is melted, uneven current density distribution occurs, causing local conduction failure, resulting in insoluble slime. May occur, leading to poor plating and reduced production efficiency. As a countermeasure, it is effective to increase the in-plane melting homogeneity at the melting surface of the anode, and a countermeasure is taken by making the crystal grains finer. However, in general, the grain boundaries are easier to dissolve than in the grains, and even if the in-plane dissolution homogeneity of the anode is improved by refinement, it is inevitable that the grain boundaries are selectively dissolved, and the refinement effect is limited. It has turned out that there is. Therefore, it is considered that suppressing the solubility of the grain boundary itself is effective for the generation of the slime, but no examination has been made from such a viewpoint.

Furthermore, since the heat dissipation substrate repeatedly expands and contracts during use, it is important to have uniform deformation characteristics and excellent fatigue characteristics. In recent years, direct and alternating inverter circuits are indispensable for hybrid vehicles and solar cells that have become popular due to the trend of energy saving and low CO. Pure copper or low alloy is used as a heat dissipation board to dissipate the heat generated during conversion. A copper plate is used. In these applications, an increase in current due to an increase in the size of the system is progressing, and the heat burden on the heat dissipation substrate is increasing. Since heat expansion and contraction are always repeated during use, the heat dissipation substrate is required to have heat fatigue characteristics in the long term. Regarding the heat resistance fatigue characteristics, the homogeneity of the structure is important, but it is difficult to improve the fatigue characteristics accompanying the increase in current only by improving the homogeneity of the conventional structure.

These problems can be solved by setting the length ratio of the special grain boundaries to 55% or more. That is, since the sputtering target is sputtered uniformly over the entire sputtering surface, a step in the crystal grain boundary that causes abnormal discharge hardly occurs, and as a result, the number of abnormal discharges is reduced. As for the anode for plating, special grain boundaries were found to have properties closer to the dissolution characteristics in the grains than general grain boundaries, and by using a copper plate with a higher special grain boundary ratio, Since the in-plane dissolution homogeneity is remarkably improved and the dissolution surface is kept smooth, the generation of insoluble slime is suppressed and the quality of the formed plating film is improved. In addition, the substrate material for heat dissipation shows uniform deformation characteristics, and metal fatigue hardly occurs even by repeated thermal expansion / contraction, and the fatigue characteristics are improved.
Thus, by setting the length ratio of the special grain boundary to 55% or more, various characteristics such as sputtering characteristics in the sputtering target, solubility in the anode material for plating, and other deformation characteristics as a copper plate are improved. This is effective for applications such as plating anodes and heat dissipation substrates.

Next, a method for producing such a pure copper plate will be described.
This manufacturing method is a simple process in which a pure copper ingot is hot-rolled, the hot rolling is finished in a finish rolling pass that satisfies a predetermined condition, and then rapidly cooled as necessary.
Specifically, a pure copper ingot is heated to 550 ° C. to 800 ° C., and while reciprocating between the rolling rolls a plurality of times, the gap between the rolling rolls is gradually reduced and rolled to a predetermined thickness. The total rolling rate by this multiple rolling is 85% or more, the finishing temperature in finishing hot rolling, which is the finishing process of hot rolling, is 500 to 700 ° C., and the reduction per pass in the finishing hot rolling. The rate is 5 to 24%, and one or more passes are continuously rolled. Thereafter, if necessary, rapid cooling is performed at a cooling rate of 200 to 1000 ° C./min from the rolling end temperature to a temperature of 200 ° C. or lower.

In general, a method for producing a pure copper sheet generally includes a process of hot rolling → cooling → cold rolling → heat treatment, and the hot rolling in this case is processed at a high temperature of 850 to 900 ° C. When hot rolling is performed in such a high temperature state, the crystal grains become coarse, so even if it is rapidly cooled, the average crystal grain size cannot be reduced to 80 μm or less.

In the manufacturing method of the present embodiment, hot rolling was performed at a relatively low temperature state with a start temperature of 550 to 800 ° C. and an end temperature of 500 to 700 ° C. When the end temperature of hot rolling exceeds 700 ° C., the crystal grains increase rapidly, and it is difficult to obtain fine crystal grains even if the crystal is rapidly cooled thereafter. Even if the hot rolling end temperature is less than 500 ° C., the effect of refining the crystal grain size is saturated, and even if the temperature is lowered below that, it does not contribute to the refining. Therefore, the rolling end temperature is set to 500 to 700 ° C. In order to set the end temperature of this hot rolling to 500 to 700 ° C., the hot rolling start temperature was set to 550 to 800 ° C.

Further, the total rolling rate by this hot rolling is preferably 85% or more, and by setting the total rolling rate to 85% or more, the coarsening of the crystal grain size can be suppressed and the variation can be reduced. . If the total rolling ratio is less than 85%, the crystal grains tend to be large and the variation becomes large. In this case, with respect to the finish hot rolling which is the final stage rolling among a plurality of rollings, it is more preferable to perform rolling continuously for one pass or a plurality of passes with a reduction rate per pass of 5 to 24%. By setting the reduction rate per pass at 5 to 24% at the final stage of hot rolling, the ratio of twin structure increases, and the length ratio of the special grain boundary at the grain boundary becomes 55% or more. can do. The rolling reduction per pass is the reduction rate of the thickness of the base material after passing the rolling roll relative to the thickness of the base material before passing the rolling roll (or the rolling of the current pass relative to the gap between the rolling rolls in the previous pass) The reduction rate of the gap between rolls), and the total rolling rate is the rate of reduction of the thickness of the base metal after the rolling relative to the base material before rolling. That, t ₀ the thickness of the base material before passing the rolling _rolls, when the plate thickness of the base material after passing through the rolling rolls and t _1, the rolling reduction per pass gamma (%) is, gamma = ((t ₀₋ t ₁ ) / t ₀ ) × 100 (%).

Then, after completion of such hot rolling, the grain size after hot rolling can be suppressed by quenching with water cooling at a cooling rate of 200 to 1000 ° C./min until a temperature of 200 ° C. or lower is reached. . If the cooling rate is less than 200 ° C./min, the effect of suppressing the growth of crystal grains is poor, and even if it exceeds 1000 ° C./min, it does not contribute to further miniaturization.
If it is cooled to a temperature of 200 ° C. or less at a cooling rate in such a range, the growth of crystal grains can be stopped to obtain fine crystal grains. If the rapid cooling is stopped at a temperature exceeding 200 ° C., the crystal grains may gradually grow by being left in the high temperature state.

Next, examples of the present invention will be described.
The rolling material used was a cast ingot of oxygen-free copper (purity 99.99 wt% or more) for electron tubes. The raw material dimensions before rolling were 650 mm wide × 900 mm long × 290 mm thick, and a pure copper plate was prepared by combining a plurality of hot rolling and subsequent cooling conditions as shown in Table 1. The temperature was measured by measuring the surface temperature of the rolled plate using a radiation thermometer.

In Table 1, Comparative Example 1 started rolling at a rolling start temperature of 510 ° C. (expected end temperature of 490 ° C.). However, since the temperature was too low, it was overloaded and the continuation of rolling was stopped.
Therefore, with respect to pure copper plates other than Comparative Example 1, the average crystal grain size, the special grain boundary length ratio, the mushy state during cutting, the number of abnormal discharges when used as a sputtering target, and the occurrence of slime when used as a plating anode The amount was measured.

<Average crystal grain size, special grain boundary length ratio>
Each sample was mechanically polished using water-resistant abrasive paper and diamond abrasive grains, and then final polished using a colloidal silica solution.
By using an EBSD measuring device (HITACHI S4300-SE, EDAX / TSL OIM Data Collection) and analysis software (EDAX / TSL OIM Data Analysis ver. 5.2), grain boundaries and special grain boundaries The average grain size and the special grain boundary length ratio were analyzed by specifying the length and calculating the length.

First, using a scanning electron microscope, each measurement point (pixel) within the measurement range on the sample surface is irradiated with an electron beam, and the orientation difference between adjacent measurement points is determined by orientation analysis by backscattered electron diffraction. The crystal grain boundary was defined between the measurement points at 15 ° or more.
The average crystal grain size (twins are counted as crystal grains) is calculated from the obtained grain boundaries by calculating the number of crystal grains in the observation area and dividing the area by the number of crystal grains to calculate the crystal grain area. The average crystal grain size (diameter) was calculated and converted into a circle.
In addition, the total grain boundary length L of the crystal grain boundary in the measurement range is measured, the position of the crystal grain boundary where the interface between adjacent crystal grains constitutes the special grain boundary is determined, and all the special grain boundaries of the special grain boundary are determined. The grain boundary length ratio Lσ / L between the length Lσ and the total grain boundary length L of the crystal grain boundary measured above was determined and used as the special grain boundary length ratio.

<Musille state>
Each sample was made into a flat plate of 100 × 2000 mm, and its surface was cut with a milling machine with a cutting edge of a cutting edge of 0.1 mm and a cutting speed of 5000 m / min, within the 500 μm square field of view of the cutting surface. It was examined how many mussels with a length of 100 μm or more were present.

<Number of spatter abnormal discharge>
An integrated target including a backing plate portion is prepared so that the target portion has a diameter of 152 mm and a thickness of 6 mm from each sample, the target is attached to a sputtering apparatus, and the ultimate vacuum pressure in the chamber is 1 × 10 ⁻ Sputtering tests were performed under conditions of ⁵ Pa or less, Ar as the sputtering gas, sputtering gas pressure of 0.3 Pa, and sputtering output of 2 kW with a direct current (DC) power source. Sputtering was continued for 2 hours. During this time, the number of abnormal discharges caused by sputtering abnormality was counted using an arc counter attached to the power source.

<Anode slime generation amount>
A copper plate cut out in a disk shape having a diameter of 270 mm is fixed to an electrode holder (effective electrode area of about 530 cm ² ) to be an anode electrode, and a silicon wafer having a diameter of 200 mm is used as a cathode to perform copper plating under the following conditions. The amount of insoluble slime generated when processing up to the first wafer was measured. The slime was weighed after being recovered and dried.
Plating solution: 70 g / l copper pyrophosphate and 300 g / l potassium pyrophosphate added to ion exchange water, adjusted to pH 8.5 with ammonia water,
Plating conditions: air stirring at a liquid temperature of 50 ° C. and stirring by cathode swing,
Cathode current density: 3 A / dm ²
Plating time: 1 hour / sheet.
These results are shown in Table 2.

As is apparent from Table 2, the pure copper plate produced by the production method of this example has an average crystal grain size of 10 to 200 μm, and particularly 10 to 80 μm for Examples 1 to 10 that were rapidly cooled after finish rolling. In all the examples, the special grain boundary length ratio was 55% or more. On the other hand, the pure copper plate of the comparative example had a special grain boundary length ratio of less than 55%. As a result, in the examples, the final rolling at the time of hot rolling was reduced to 5 to 24%, the number of abnormal discharges during sputtering was small in the sputtering target characteristic evaluation, and insoluble in the plating anode dissolution characteristic evaluation. It can be seen that the amount of slime generated is small.

Although the embodiment of the present invention has been described above, the present invention is not limited to this description and can be appropriately changed without departing from the technical idea of the present invention.
For example, the rolling reduction is made constant when performing multiple passes in the finish rolling pass schedule of hot rolling, but is not limited to this, and rolling is performed if the rolling reduction is 5 to 24% per pass. The rolling reduction for each pass may be different.
In addition, in order to obtain a high special grain boundary ratio, it is not necessary to cool immediately after the finish rolling pass, but since it is effective in enhancing the homogeneity of the structure inside and on the ingot, it is promptly cooled. It is better to do it.

Further, the present invention, after hot rolling under a predetermined condition, is rapidly cooled to 200 ° C. or less, and thereafter is a product of a pure copper plate without being subjected to cold rolling. This does not prevent cold rolling (with a rolling rate of several percent or less).

The pure copper plate of the present invention can be applied to a sputtering target, a plating anode, and a target backing plate. In addition, a mold, a discharge electrode, a heat sink, a heat sink, a mold, a water-cooled plate, an electrode, an electrical terminal, It can also be applied to bus bars, gaskets, flanges, printing plates and the like.

W Cutting mark C Musile

Claims (8)

1. A pure copper ingot having a purity of 99.96 wt% or more is heated to 550 ° C. to 800 ° C., the total rolling rate is 85% or more, the temperature at the end of rolling is 500 to 700 ° C., and per pass A method for producing a pure copper sheet, characterized by performing a hot rolling process having a finish rolling with a rolling reduction of 5 to 24% for one pass or more.
2. A pure copper ingot having a purity of 99.96 wt% or more is heated to 550 ° C. to 800 ° C., the total rolling rate is 85% or more, the temperature at the end of rolling is 500 to 700 ° C., and per pass After performing a hot rolling process having a finish rolling with a rolling reduction of 5 to 24% for one or more passes, rapid cooling is performed at a cooling rate of 200 to 1000 ° C./min from the temperature at the end of rolling to a temperature of 200 ° C. or less. A method for producing a pure copper sheet.
3. A ratio of the total special grain boundary length Lσ of the special grain boundary to the total grain boundary length L of the crystal grain boundary measured by the EBSD method (Lσ / A pure copper plate, wherein L) is 55% or more.
4. A pure copper plate manufactured by the manufacturing method according to claim 2, wherein the ratio of the total special grain boundary length Lσ of the special grain boundary to the total grain boundary length L of the crystal grain boundary measured by the EBSD method (Lσ / A pure copper plate, wherein L) is 55% or more.
5. The pure copper plate according to claim 3, which is a sputtering target.
6. The pure copper plate according to claim 4, which is a sputtering target.
7. The pure copper plate according to claim 3, which is a plating anode.
8. The pure copper plate according to claim 4, which is a plating anode.

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