KR20170036813A - Pure copper plate production method, and pure copper plate - Google Patents

Abstract

There is provided a method for producing a pure copper plate having a fine crystal structure and having a suitable hardness and a high specific gravity length ratio and a pure copper plate such as a sputtering target or an anode for plating manufactured by the method . A pure copper ingot having a purity of 99.96 wt% or more is heated to 550 to 800 占 폚, subjected to hot rolling at a rolling rate of 80% or more and a rolling finish temperature of 500 to 700 占 폚, Quenched at a cooling rate of 200 to 1000 캜 / min until the temperature is reached, and then cold-rolled and annealed at a rolling rate of 5 to 24%.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a pure copper plate and a pure copper plate,

The present invention relates to a method for producing a pure copper plate having good quality, particularly a method for producing a pure copper plate having a fine crystal structure and having a suitable hardness and forming a twin crystal structure by partial recrystallization, And a pure copper plate of a material such as a sputtering target or an anode for plating manufactured by the method for producing the pure copper plate.

The present application claims priority based on Japanese Patent Application No. 2010-26453 filed on February 9, 2010, the contents of which are incorporated herein by reference.

The pure copper plate is usually manufactured by subjecting an ingot of pure copper to hot rolling or hot forging, followed by cold rolling or cold forging, followed by heat treatment for deformation or recrystallization. Such a pure copper plate is processed and used in a desired shape by sawing, cutting, embossing, cold forging or the like, but it is also required to have a small crystal grain size in order to reduce roughness during processing.

In addition, the pure copper plate produced by the above-described method is recently used as a sputtering target for a wiring material of a semiconductor device. Al (a resistivity of about 3.1 mu OMEGA .cm) has been used as a wiring material of a semiconductor device. However, copper wires with a lower resistance (about 1.7 mu OMEGA .cm in specific resistance) have been put to practical use with recent miniaturization of wirings. In this copper wiring formation process, copper is often electroplated after a diffusion barrier layer of Ta / TaN or the like is formed in the concave portion of the contact hole or the wiring groove. In order to perform the electroplating, Seed layer) of pure copper is sputter deposited.

Generally, an electric copper of about 4 N (purity of 99.99% or more: gas component removed) is formed into a rough metal by a wet or dry high-purity process to obtain a purity of 5 N (purity 99.999% Purity of 99.9999% or more) is prepared, which is used as a pure copper plate by the above-described method, and is used as a sputtering target after being processed into a desired shape again. In order to produce a sputter film having a low electrical resistance, it is necessary to reduce the content of impurities in the sputtering target to a predetermined value or less and to reduce the element added to the alloy to a certain level or less. In order to obtain the uniformity of the sputtering film thickness, It is necessary to suppress the deviation of crystal grain size and crystal orientation of the sputtering target.

As a conventional method for industrially producing such a pure copper target for sputtering, Patent Document 1 discloses a method for hot working an ingot of pure copper having a purity of 99.995 wt% or more, annealing it at a temperature of 900 캜 or less, A cold rolled steel sheet is subjected to cold rolling at a rolling rate of 40% or more and recrystallization annealing at a temperature of 500 DEG C or lower to obtain a copper target for sputtering having a substantially recrystallized structure and having an average crystal grain size of 80 microns or less and a Vickers hardness of 100 or less A method of obtaining the same is disclosed.

Patent Document 2 discloses a method of hot working a high purity copper ingot of 5 N or more at a machining rate of 50% or more such as hot forging or hot rolling and then further performing cold working at a machining rate of 30% or more such as cold rolling or cold forging The content of Na and K is respectively 0.1 ppm or less and the contents of Fe, Ni, Cr, Al, Ca, and Mg are respectively 1 ppm or less and the contents of carbon and oxygen are 1 ppm or less, respectively, by performing the heat treatment at 350 to 500 ° C for 1 to 2 hours. Each having a content of U and Th of 1 ppb or less, a content of copper with a gas content of 99.999% or more, an average grain size of 250 탆 or less on the sputter surface, and a deviation of an average grain size of 20% Of an X-ray diffraction intensity ratio I (111) / I (200) of not less than 2.4 on the sputter surface and a deviation of within ± 20%.

Patent Document 3 discloses an aluminum ingot having 0.5 to 4.0 wt% of Al, which is obtained by removing a surface layer of an ingot produced from high purity copper having a purity of 6 N or more and an ingot made from an additive element and performing the hot forging, hot rolling, cold rolling, A copper alloy sputtering target having Si of 0.5 wtppm or less, a copper alloy sputtering target containing 0.5 to 4.0 wt% of Sn and 0.5 wt ppm or less of Mn, and a copper alloy sputtering target containing Sb, Zr, Ti, Cr, Ag, Au, As, a copper alloy sputtering target containing not more than 1.0 wtppm, as a total amount, of one or more selected. Particularly, in the examples, the surface layer of the produced ingot was removed to make a diameter of 160 mm and a thickness of 60 mm, followed by hot forging at 400 DEG C to make a diameter of 200 mm, and then hot rolling at 400 DEG C to form , Further rolled to φ360 mm × 10 mm in thickness by cold rolling, subjected to a heat treatment at 500 ° C. for 1 hour, and then the entire target is quenched to obtain a target material.

In order to obtain a homogeneous and stable recrystallized structure, the pure copper ingot is hot-forged or hot-rolled and then subjected to cold forging or cold rolling Rolled, and further heat-treated.

Japanese Patent Application Laid-Open No. 11-158614 Japanese Patent Application Laid-Open No. 10-330923 Japanese Laid-Open Patent Publication No. 2009-114539

However, in a conventional method for industrially producing a pure copper plate having a uniform and stable crystal structure of a large shape, it is necessary to subject the pure copper ingot to hot forging or hot rolling and then to perform additional cold forging, cold rolling and heat treatment However, when the pure copper plate is used for a sputtering target, an anode for plating, or a heat dissipation substrate, it is possible to suppress an abnormal discharge in a sputter over a long period of time in a sputtering target, to improve the in-plane dissolution homogeneity in a plating anode, It has been difficult to cope with such a characteristic only by refinement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a sputtering target material or an anode material for plating, which comprises rolling a cold rolled steel sheet, Another object of the present invention is to provide a pure copper plate suitable for a sputtering target or an anode for plating by providing a special grain boundary ratio by forming a twin crystal structure by partial recrystallization by further annealing to form a fine crystal structure.

As a result of intensive studies, the inventors of the present invention have found that ingot of pure copper is hot-rolled under a certain condition to suppress the growth of crystal grains, quenched under a certain condition to stop the grain growth, and then subjected to cold rolling and heat treatment, It has been found that a pure copper plate suppressing the abnormal discharge during sputtering and suppressing the generation of insoluble slime during plating can be manufactured by setting the length ratio of the special grain boundaries measured by the EBSD method to 25% or more.

A method for producing a pure copper plate according to the present invention is characterized in that ingot of pure copper having a purity of 99.96 wt% or more is heated to 550 to 800 캜 and hot rolled with a total rolling ratio of 80% or more and a temperature of 500 to 700 캜 , Quenched at a cooling rate of 200 to 1000 占 폚 / min until the temperature becomes 200 占 폚 or lower from the temperature at the end of the rolling, and then cold-rolled and annealed at a rolling rate of 5 to 24% do.

In order to obtain fine crystal grains, it is effective to apply a large energy by hot rolling followed by quenching. In that case, it is important to suppress the hot rolling end temperature to 500 to 700 占 폚. If the hot rolling end temperature exceeds 700 캜, the crystal grains sharply increase, and it is difficult to obtain fine crystal grains even after quenching. Even if the hot rolling end temperature is less than 500 ° C, the effect of making the crystal grain size finer is saturated, and even if the temperature is lowered, it does not contribute to the miniaturization. In addition, when the rolling temperature is low, excessive energy is required to obtain the desired total rolling rate, which makes processing difficult. In order to set the hot rolling end temperature to 500 to 700 캜, the hot rolling starting temperature was set to 550 to 800 캜.

The total rolling ratio by hot rolling is preferably 80% or more, and the increase of the crystal grains can be suppressed by a large energy at a total rolling ratio of 80% or more, and the deviation can be reduced . If the total rolling ratio is less than 80%, the crystal grains tend to be large and the deviation becomes large.

After completion of the hot rolling, quenching is carried out at a cooling rate of 200 to 1000 占 폚 / min until the temperature reaches 200 占 폚 or lower. When the cooling rate is less than 200 캜 / min, the effect of suppressing the growth of crystal grains is insufficient, and even if the heating rate is more than 1000 캜 / min, it does not contribute to further miniaturization. A more preferable cooling rate is in the range of 300 to 600 占 폚 / min.

When cooling is carried out at a cooling rate of 200 ° C or lower in such a range, the growth of crystal grains is stopped to obtain fine crystal grains. When quenching is stopped at a temperature exceeding 200 캜, there is a fear that the crystal grains are gradually grown by being left in the high temperature state.

After this quenching, cold rolling and annealing at a rolling rate of 5 to 24% are carried out to reduce the crystal grain size and to form a twin crystal structure by partial recrystallization, thereby giving a high specific grain boundary ratio.

The pure copper plate produced by the manufacturing method of the present invention has a ratio (specific grain boundary length ratio, L?) Of the total specific grain boundary length L? Of the special grain boundaries to the total grain boundary length L of grain boundaries measured by the EBSD method / L) is 25% or more.

It is further preferable that the average crystal grain size measured by the EBSD method is 10 to 120 占 퐉 and the Vickers hardness is 40 to 90.

Particularly, the above-mentioned special grain boundary length ratio is 25% or more, whereby the consistency of crystal grain boundaries is improved, and various characteristics such as suppression of abnormal discharge in the sputtering target of the sputtering target and improvement of the in-plane dissolution homogeneity of the plating anode are improved.

The pure copper plate of the present invention is preferably used for a sputtering target or a plating anode.

As described above, the pure copper plate of the present invention has a fine crystal grain size and a special grain boundary length ratio of 25% or more. Thus, when used as a sputtering target, abnormal discharge can be suppressed for a long time, , The in-plane dissolution homogeneity is improved and the occurrence of insoluble slime can be suppressed.

According to the present invention, since the grain size is fine and the specific grain boundary length ratio is 25% or more, the target and in-plane dissolution homogeneity which can suppress the abnormal discharge for a long time can be improved and the occurrence of insoluble slime can be suppressed An anode can be provided.

1 is a photomicrograph of a dross produced when a 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 having an electron purity of 99.99 wt% or more.

The average grain size of the rolled plate of the present invention is 10 to 120 占 퐉, the Vickers hardness is 40 to 90, and the specific grain boundary length ratio measured by the EBSD method is 25% or more.

If large crystal grains having a crystal grain size exceeding 200 mu m are mixed, fine scratches on the surface are apt to occur in the cutting process. As shown in Fig. 1, when cutting a workpiece with a pricey or the like, the machining tool is provided with a machining tool for machining a workpiece W in a cutting direction (a direction indicated by an arrow A) As shown in Fig. If this crumbling occurs, the appearance of the product will be damaged.

In addition, it is not realistic to make the average crystal grain size smaller than 10 mu m, resulting in an increase in manufacturing cost.

In addition, by forming a twin crystal structure by partial recrystallization and setting the specific grain boundary length ratio to 25% or more, the grain boundary matching property is improved, which is effective for applications such as a sputtering target and a plating anode.

The crystal grain boundaries are defined as the boundaries between the crystals when the orientation between two neighboring crystals is 15 degrees or more as a result of the two-dimensional cross-section observation. The special grain boundaries are crystal grain boundaries with 3 ≤ Σ ≤ 29 as Σ values defined on the basis of CSL theory (Kronberg et al .: Trans. Met. Soc. AIME, 185, 501 (1949) as a grain boundary), the corresponding unique grating orientation defect site (Dq) is Dq≤15 ° / Σ ^1/2 (DG Brandon in the art grain boundary: determining satisfying Acta Metallurgica Vol.14, p 1479, 1966 ) grain boundary .

When the ratio of the length of the special grain boundaries is high in all the crystal grain boundaries, the coherence of grain boundaries is improved, and the characteristics of the sputtering target, the plating anode, and the heat dissipation substrate widely known as the applications of the pure copper plate can be improved.

That is, in the sputtering target, there is a correlation between the anomalous discharge characteristics at the time of sputtering and the crystal structure, so that the material is made highly pure, that is, the amount of the impurity contained therein is reduced (JP 2002-129313 A), the homogeneity WO 03/046250), control of the crystal orientation of the texture (Japanese Patent Application Laid-open No. Hei 10-330923), and the like, discloses means for suppressing abnormal discharge in sputter characteristics. However, in recent years, further improvement of the sputter rate is required for the purpose of improving the productivity, and the sputter voltage is in the direction of high voltage. If the sputter voltage is improved, an abnormal discharge during sputtering becomes more likely to occur. Therefore, the conventional tissue control method alone has insufficient effect of suppressing the abnormal discharge, and a new tissue control has been required.

In addition, the anode material for plating made of pure copper is used particularly for through-hole plating of a printed wiring board, and the current density distribution is uneven at the time of anode dissolution, causing local conduction failure, resulting in insoluble slime, Or a decrease in production efficiency. As a countermeasure, it is effective to increase the in-plane dissolution homogeneity on the dissolving surface of the anode, and countermeasures are taken by finer crystal grains. However, in general, the grain boundaries are liable to be dissolved in the mouth, and even if the in-plane dissolution homogeneity of the anode is improved due to refinement, it is inevitable that the grain boundaries are selectively dissolved, which has been found to be limited. Therefore, it is considered that the inhibition of the solubility of the grain boundary itself is effective for the generation of the slime, but such a study has not been made in the past.

Further, in the heat dissipation substrate, since expansion and contraction are repeated at the time of use, it is important that the heat dissipation substrate has uniform deformation characteristics and excellent fatigue characteristics. In recent years, in hybrid cars and solar cells, which are being promoted by energy conservation and low CO conversion, straight and bridge inverter circuits are indispensable. As heat dissipation boards for heat dissipation during conversion, pure copper or low alloy Copper plates are used. In these applications, large currents are being made due to the enlargement of the system, and the heat load applied to the heat dissipation substrate is increased. Since the thermal expansion / contraction of the heat dissipation substrate is repeated at all times during use, heat-resistant fatigue characteristics are required in the long term. Although the homogeneity of the structure is important with respect to the heat-resistant fatigue characteristic, it is difficult to improve the fatigue characteristics accompanied with the above-mentioned large current only by improving the uniformity of the conventional structure.

These problems can be solved by making the average crystal grain size finer and making the length ratio of the grain boundaries of the grain boundaries 25% or more. That is, in the sputtering target, since the sputter is uniformly sputtered on the entire surface of the sputtering target, the step of the grain boundaries that cause the abnormal discharge is unlikely to occur, and as a result, the number of abnormal discharges is reduced. As for the anode for plating, it has been found that the special grain boundary has a property close to the dissolution characteristics in the grain than the grain boundary in general grain. The use of the copper plate with a special grain boundary ratio significantly improves the in-plane dissolution homogeneity during the anode dissolution, So that the generation of insoluble slime is suppressed and the quality of the formed plated film is improved. Further, the heat dissipation substrate exhibits uniform deformation characteristics, and metal fatigue does not occur even by repeated thermal expansion and thermal shrinkage, thereby improving the heat-resistant fatigue characteristics.

As described above, by setting the length ratio of the special grain boundaries to 25% or more, it is possible to suppress the abnormal discharge in the sputtering target, suppress the generation of insoluble slime in the plating anode, Characteristics and the like can be seen, which is preferable for a sputtering target, an anode for plating, and a heat dissipation substrate.

Next, a method for manufacturing such a pure copper plate will be described.

First, the ingot of pure copper is heated to 550 ° C. to 800 ° C., and the gap between the rolling rolls is gradually reduced while being reciprocated between the rolling rolls a plurality of times, thereby rolling to a predetermined thickness. The rolling rate by this plural rolling becomes 80% or more, and the temperature at the end of rolling becomes 500 to 700 占 폚. Thereafter, it is quenched at a cooling rate of 200 to 1000 占 폚 / min until the temperature becomes 200 占 폚 or less from the temperature at the end of rolling. Thereafter, it is cold-rolled at a rolling rate of 5 to 24% and annealed by heating at 250 to 600 ° C for 30 minutes to 2 hours.

In a typical method for producing a pure copper plate, hot rolling is performed at a high temperature of 850 to 900 ° C in a process of hot rolling -> cooling -> cold rolling -> heat treatment. When hot rolling at such a high temperature condition, crystal grains are coarsened, even if quenched, the average crystal grain size can not be reduced to 80 탆 or less.

In the production method of the present embodiment, hot rolling is performed at a relatively low temperature of 550 to 800 占 폚 at the start temperature and 500 to 700 占 폚 at the end temperature. If the end temperature of the hot rolling exceeds 700 ° C, the crystal grains sharply increase, and it is difficult to obtain fine crystal grains even after quenching. Even if the hot rolling end temperature is lower than 500 占 폚, the effect of miniaturization of the crystal grain size is saturated, and even if the temperature is lowered, it does not contribute to miniaturization. In addition, when the rolling temperature is low, excessive energy is required to obtain the desired total rolling rate, which makes processing difficult. Therefore, the rolling finish temperature was set to 500 to 700 ° C. In order to set the end temperature of the hot rolling to 500 to 700 캜, the starting temperature of hot rolling was set to 550 to 800 캜.

The rolling rate by the hot rolling is preferably 80% or more. By setting the rolling rate to 80% or more, coarsening of the crystal grain size can be suppressed and the deviation can be reduced. From this point of view, it is preferable to set the rolling rate to 80% or more. If the rolling rate is less than 80%, the crystal grains tend to be large and the deviation becomes large. It is more preferable to set the reduction ratio per pass to 25% or more for the rolling of the final stage among the plurality of rolling performed to achieve the rolling rate. By reducing the rolling reduction rate to 25% or more at the final stage of the hot rolling, it is possible to prevent the coexistence of large crystal grains, thereby making the crystal grains more uniform as a whole. The final stage rolling may be performed from 1 pass to several passes at a reduction rate of 25% or more. The reduction rate per one pass is a rate of reduction of the plate thickness of the base material after passing through the rolling roll with respect to the plate thickness of the base material before passing through the rolling roll (or between the rolling rolls of the current path with respect to the gap between the rolling rolls at the previous pass Gap reduction rate), and the total rolling ratio is a reduction rate of the plate thickness of the base material after completion of rolling on the base material before rolling. That is, assuming that the plate thickness of the base material before passing through the rolling roll is t ₀ and the plate thickness of the base material after passing through the rolling roll is t ₁ , the reduction ratio γ (%) per one pass is γ = ((t ₀ -t ₁ ) / t ₀ ) x 100 (%).

After the end of the hot rolling, the steel is quenched by cooling at a cooling rate of 200 to 1000 占 폚 / min until the temperature becomes 200 占 폚 or lower. When the cooling rate is less than 200 캜 / min, the effect of suppressing the growth of crystal grains is insufficient, and even if the heating rate is more than 1000 캜 / min, it does not contribute to further miniaturization.

When cooling is carried out at a cooling rate of 200 ° C or lower in such a range, the growth of crystal grains is stopped to obtain fine crystal grains. When quenching is stopped at a temperature exceeding 200 캜, there is a fear that the crystal grains are gradually grown by being left in the high temperature state.

The cold rolling is then carried out in order to improve the hardness and strength, to obtain a good surface state by increasing the flatness, and then to carry out a heat treatment so as to increase the length ratio of the grain boundaries of the grain boundaries to 25% The rolling rate is 5 to 24%. If the rolling rate is less than 5%, it is difficult to obtain the desired special grain boundary ratio, and if it exceeds 24%, the further effect can not be seen.

The annealing treatment is carried out in order to form a twin crystal structure by partial recrystallization using the strain energy introduced by cold rolling to improve the specific grain boundary length ratio. The annealing temperature is preferably 250 to 600 占 폚, and it may be maintained in the heating atmosphere for 30 to 120 minutes.

Example

Next, an embodiment of the present invention will be described.

Casting ingots of oxygen free copper (purity 99.99 wt% or more) for electron pipes were used as the rolling material. The material dimensions before the rolling were 650 mm in width x 900 mm in length x 290 mm in thickness and a plurality of conditions after hot rolling were combined as shown in Table 1 to prepare a pure copper plate. The temperature was measured by measuring the surface temperature of the rolled plate using a radiation thermometer.

Next, with respect to the pure copper plate shown in Table 1, the average grain size, the specific grain boundary length ratio, the Vickers hardness, the number of abnormal discharges in the sputtering when used as the sputtering target, and the number of the insoluble slimes Was measured.

<Average crystal grain size, specific grain boundary length ratio>

Each sample was subjected to mechanical polishing using a water-borne abrasive paper and diamond abrasive grains, and then subjected to finish polishing using a colloidal silica solution.

The crystal grain boundaries and the special grain boundaries are specified by an EBSD measuring device (S4300-SE manufactured by HITACHI Corporation, OIM Data Collection manufactured by EDAX / TSL) and analysis software (OIM Data Analysis ver. 5.2 produced by EDAX / TSL) And the average grain size and the specific grain boundary length ratio were analyzed by calculating the length.

First, an electron beam is irradiated to individual measurement points (pixels) within the measurement range of the surface of the sample using a scanning electron microscope, and the azimuthal difference between the adjacent measurement points is 15 degrees or more And the measurement point was determined as the grain boundary.

The average crystal grain size (counted as twin crystal grains) is calculated by calculating the number of crystal grains in the observation area from the crystal grain boundaries obtained, calculating the area of the crystal grains by dividing the area area by the number of crystal grains, Crystal grain size (diameter).

The total grain boundary length (L) of the grain boundaries in the measurement range is measured and the position of the grain boundaries constituting the special grain boundaries is determined by the interface of adjacent crystal grains, and the total specific grain boundary length (L? / L) between the grain boundary length (L?) And the total grain boundary length (L) of the grain boundaries measured was determined as a special grain boundary length ratio.

<Vickers hardness>

The Vickers hardness was measured by a method specified in JIS (Z2244) for the longitudinal section along the rolling direction (R.D. direction) (T.D. direction).

&Lt; Number of spatter abnormal discharge &gt;

The target portion 152 ㎜ diameter from each sample, to produce a one-piece target, including a portion of the backing plate such that the thickness 8 ㎜ mounted in a sputtering apparatus, and the vacuum pressure in the chamber below the reaching 1 × 10 ^-5 ㎩, high purity as a sputtering gas The sputter gas pressure was set to 0.3 Pa using Ar, and continuous sputtering was performed for 8 hours under the condition of a direct current (DC) power supply and a sputter output of 1 kW. The total number of abnormal discharges was counted by using an arcing counter attached to the power source.

&Lt; Anode slime generation amount &

 Copper plating was performed under the following conditions using a silicon wafer having a diameter of 200 mm as a cathode by fixing a copper plate cut out on a disk-shaped disk having a diameter of 270 mm to an electrode holder (running electrode area: about 530 cm2) The insoluble slimes generated when the wafers were treated from the fifth to the fifth wafers were sampled, and the slime generation amount was measured. The slime generation amount was obtained by weight measurement after recovery of the slime and drying.

Plating solution: Ion-exchanged water was prepared by adding 70 g / l of copper pyrophosphate, 300 g / l of potassium pyrophosphate and 15 g / l of potassium nitrate and adjusting the pH to 8.5 with ammonia water,

Plating condition: stirring at air temperature of 50 占 폚 by air agitation and cathode oscillation,

Cathode current density: 2 A / dm ² ,

Plating time: 1 hour / long.

<Crest state>

Each sample was made into a flat plate having a size of 100 mm × 2000 mm and the surface thereof was cut by a prism half at a cutting depth of 0.2 mm and a cutting speed of 5000 m / It was investigated how many scratch marks with a length of 100 占 퐉 or more existed in the field of view of 탆 square.

These results are shown in Table 2.

As apparent from Table 2, the pure copper plate produced by the manufacturing method of this embodiment had an average crystal grain size of 10 to 120 탆, a hardness of 40 to 90 Hv, a specific grain boundary length ratio of 25% Or more. On the other hand, in the pure copper plate of the comparative example, the average crystal grain size, hardness or special grain boundary length ratio deviate from the range. As a result, it can be seen that the number of abnormal discharges in the sputtering target of the embodiment is extremely low, and the amount of insoluble anode slime generated in the evaluation of dissolution characteristics when used as a plating anode is also extremely low. On the other hand, in the comparative example, it was observed that the number of abnormal discharges was larger and the amount of the anode slime was increased as compared with the examples, and that a roughness was generated in the surface state after machining.

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 invention.

Industrial availability

The pure copper plate of the present invention is applicable to a sputtering target and a backing plate for a target and is also applicable to a plating anode, a mold, a discharge electrode, a heat sink, a heat sink, a mold, Bar, gasket, flange, printing plate, and the like.

W: Cutting spots
C: Plain marks

Claims (1)

A method for producing a pure copper plate characterized by that described in the description of the present invention.

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