JP2012201963A - Co-Si BASED COPPER ALLOY SHEET - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Co-Si-based copper alloy sheet which has excellent solder wettability and which undergoes formation of pinholes is reduced upon being soldered.SOLUTION: The Co-Si-based copper alloy sheet contains 0.5 to 3.0 mass% of Co and 0.1 to 1.0 mass% of Si, with the remainder being Cu and unavoidable impurities, wherein a requirement represented by the following formula is fulfilled: [60 degrees specular glossiness G in the direction parallel to the rolling direction (RD)]-[60 degrees specular glossiness G in direction transverse to rolling direction (TD)]=90%.

Description

  The present invention relates to a Co—Si based copper alloy sheet.

Miniaturization of electrical and electronic devices such as connectors is required, and Co-Si based copper alloys (Corson alloys) with excellent strength have been developed. By the way, the Co-Si-based Corson alloy requires solution treatment and aging treatment at high temperature to generate precipitates from Co and Si, and a strong oxide film is formed on the surface, which deteriorates solder wettability. . In the Corson alloy, since the stress relief annealing may be performed after the final rolling, the oxide film further grows. For this reason, pickling is performed after the final heat treatment to dissolve the oxide film, and further, the oxide film is removed by buffing (hereinafter referred to as “pickling buff polishing” as appropriate).
For this reason, a copper alloy material having a surface roughness Ra of 0.2 μm or less and Rt of 2 μm or less and improved solder wettability has been developed (Patent Document 1).
Also, when the above pickling buffing is performed, wrinkle-like irregularities due to the buff are generated on the surface and the solder wettability is lowered. Copper alloy materials have been developed (Patent Document 2). When pickling or degreasing treatment is performed before finish rolling, the peak position in the frequency distribution diagram representing the surface irregularity component is on the plus side (convex component) from the average line for the roughness curve (zero position in the frequency distribution diagram) ) Appears to improve solder wettability and plating properties.

International Publication WO2010 / 13790 Japanese Patent No. 4413992 (paragraph 0013)

However, in the case of the technique described in Patent Document 1, even if the solder wettability is good, the oxide film on the surface of the material is not completely removed, or pickling and polishing are performed before the final rolling. When it is pushed in, a pinhole (a region where solder does not partially adhere) is generated. If the number of pinholes increases, soldering defects are likely to occur. In particular, if a pinhole is generated in a soldered portion when a Corson alloy is formed on a terminal, soldering defects occur.
In the case of the technique described in Patent Document 2, pickling or degreasing treatment is required before finish rolling, resulting in a complicated process and poor productivity. In addition, since the oxide film of the Co-Si-based Corson alloy is very firm, it is difficult to remove by pickling alone. However, the technique described in Patent Document 2 is a process in which only pickling is performed after heat treatment and polishing is not performed, or pickling. Therefore, it is considered that the oxide film on the surface of the material is not sufficiently removed, and pinholes are likely to occur.
That is, the present invention has been made to solve the above-described problems, and an object thereof is to provide a Co—Si based copper alloy plate having excellent solder wettability and few pinholes during soldering.

As a result of various studies, the present inventors have conducted pickling buff polishing after the final heat treatment a sufficient number of times using a buff having a relatively fine eye (abrasive grains), thereby allowing an oxide film on the surface of the material or rolling. It has been found that by removing the pushed-in foreign matter and making the surface a smooth surface having a predetermined anisotropy, the solder wettability is excellent and pinholes are reduced.
In order to achieve the above object, the Co—Si based copper alloy plate of the present invention contains Co: 0.5 to 3.0 mass%, Si: 0.1 to 1.0 mass%, and the balance is Co—Si consisting of Cu and inevitable impurities. Copper alloy plate, {(60-degree specular gloss G (RD) in the direction parallel to rolling) − (60-degree specular gloss G (TD) in the direction perpendicular to rolling)} ≧ 90%.

The surface roughness Ra (RD) in the rolling parallel direction is preferably 0.07 μm.
It is preferable that the surface roughness Rz (RD) ≦ 0.50 μm in the rolling parallel direction.

It is preferable that the peak position in the frequency distribution diagram representing the concavo-convex component on the surface in the direction perpendicular to the rolling is on the minus side (concave component side) from the average line for the roughness curve.
Further, one or more selected from the group consisting of Mn, Fe, Mg, Ni, Cr, V, Nb, Mo, Zr, B, Ag, Be, Zn, Sn, Misch metal, and P are selected from 2 It is preferable to contain 0.0 mass% or less.

  According to the present invention, a Co—Si based copper alloy plate having excellent solder wettability and few pinholes during soldering can be obtained.

It is a figure which shows an example of the manufacturing process of the Co-Si type copper alloy plate which concerns on embodiment of this invention. It is a frequency distribution diagram of the unevenness | corrugation component of the surface of Example 4. FIG. It is a frequency distribution diagram of the unevenness component on the surface of Example 18.

Hereinafter, the Co—Si based copper alloy plate according to the embodiment of the present invention will be described. In the present invention, “%” means “% by mass” unless otherwise specified.
The surface roughness Ra is the centerline average roughness specified in JIS-B0601 (2001), and the surface roughness Rz is the maximum height specified in the JIS.

First, the technical idea of the present invention will be described with reference to FIG. FIG. 1 shows an example of a manufacturing process of a Co—Si based copper alloy sheet according to an embodiment of the present invention.
First, when the copper alloy plate 2 after the final heat treatment is introduced into the pickling tank 4 and pickled, the oxide film dissolves and is thinned substantially uniformly in the rolling parallel direction (RD) and the rolling perpendicular direction (TD). . Therefore, the 60 ° specular gloss G (RD) in the rolling parallel direction after pickling and the 60 ° specular gloss G (TD) in the direction perpendicular to the rolling are almost the same, and the difference between these {G (RD) −G (TD)} ≈0 (see FIG. 1A).

Next, if the copper alloy plate after pickling is polished using the buff 6, scratches on the polished eyes due to the buff are attached. In the rolling parallel direction (RD), which is the rotation direction of the buff 6, as the surface of the material advances, the oxide film that could not be dissolved by pickling disappears from the surface of the material, so that the surface of the material becomes smooth and G (RD) Becomes larger. On the other hand, even if the polishing of the material surface proceeds in the direction perpendicular to the rolling direction (TD), the surface of the material in the TD direction is scratched by buffs, so the degree of smoothness of the surface does not change significantly. TD) does not change significantly. Therefore, {G (RD) −G (TD)}> 0, but when {G (RD) −G (TD)} ≧ 90%, the buffing proceeds to sufficiently remove the oxide film, and the solder It has been found that wettability is improved and pinholes during soldering are reduced. The upper limit of {G (RD) -G (TD)} is not particularly defined, but is practically 400% or less.
The 60-degree specular gloss reflects the state of the material surface of a predetermined area. On the other hand, the surface roughness (Ra, etc.) reflects the state of the material surface on a predetermined straight line. Therefore, it is considered that the 60 ° specular glossiness better reflects the state of the oxide film or foreign matter existing locally on the material surface, rather than the surface roughness.
The buff 6 has a cylindrical shape, and abrasive grains are attached to the surface thereof. Then, the buff 6 is rotated in the forward direction of the copper alloy plate 2 (from left to right in FIG. 1) and the abrasive grains of the buff 6 scrape the surface of the copper alloy plate 2. . Therefore, the degree of removal of the oxide film due to the progress of the buffing is adjusted by the grain size (count) of the abrasive grains, the number of times of passing the copper alloy plate 2, the passing speed (line speed), the number of rotations of the buff 6, etc. be able to.

  The surface roughness Ra (RD) in the rolling parallel direction is preferably 0.07 μm or less. When Ra (RD) is 0.07 μm or less, the zero cross time may be reduced.

  In the present invention, the peak position in the frequency distribution diagram of the unevenness component on the surface in the direction perpendicular to the rolling direction can also be defined. Here, the frequency distribution diagram of the surface unevenness component is the same as that described in Patent Document 2, the horizontal axis is the height from the average line for the roughness curve, and the vertical axis is the frequency (number of measurement data). FIG. Further, in the present invention, the horizontal axis is an interval (step) of 0.05 μm in height from the average line for the roughness curve, and the number of measurement data for each interval is totaled as a frequency and plotted. The “average line for roughness curve” is standardized in JIS-B0601.

Specifically, the frequency distribution chart is created as follows. (1) First, along the direction perpendicular to the rolling direction of the sample, the “height from the average line for the roughness curve” is measured. That is, height data from the average line for the roughness curve (hereinafter referred to as “measurement data” as appropriate) is obtained for each surface position, so that the peak position and the like are obtained from the obtained measurement data and the measurement data Ra and Rz are calculated by numerical processing. (2) The height from the “average line for the roughness curve” is divided into 0.05 μm intervals. (3) The number of corresponding measurement data (frequency) is counted for each 0.05 μm interval.
Measurement data is measured at a standard length of 1.25 mm, a cutoff value of 25 mm (conforming to JIS-B0601), and a scanning speed of 0.1 mm / sec. For the measurement, a surface roughness measuring machine (Surfcoder SE3400) manufactured by Kosaka Laboratory Ltd. is used, the measurement length is 1.25 mm, and the number of measurement data is 7500 points.

The specific method for measuring the peak position is also the same as that described in Patent Document 2, and among the obtained measurement data, the height from the “average line for roughness curve” is greater than zero. The frequency distribution is plotted with the upper (plus) component classified as less than 0 and the lower (minus) component. When the horizontal axis is the height (μm) from the “average line for roughness curve” and the vertical axis is plotted again with the frequency of totaling the number of measurement data every 0.05 μm, FIG. 2 and FIG. 3 are obtained. (Corresponding to FIG. 3 of Patent Document 2). 2 and 3, when a line is drawn at a position where the height from the “average line for roughness curve” on the horizontal axis is 0 μm, the peak position of the frequency is a concave component (minus side) or a convex component (plus Side) or (or 0).
Here, the determination of the “peak position” is performed as follows. First, in the graph of height from the average line for the frequency-roughness curve (see FIGS. 2 and 3), the frequency with the highest value is P1, and the frequency with the next highest value is P2. (1) The peak position is a concave component (minus side) means that both P1 and P2 are on the minus side, or P2 / P1 <99% and P1 is on the minus side. (2) The peak position is a convex component (plus side) when P1 and P2 are both on the plus side, or when P2 / P1 <99% and P1 is on the plus side. (3) The peak position is 0 when P2 / P1 ≧ 99% (except when both P1 and P2 are on the negative side and when both P1 and P2 are on the positive side) Say.
A line having a height of 0 μm from the average line for the roughness curve means an average line for the roughness curve.
In addition, when the peak position calculated | required from the result measured 3 times varied to plus and minus, if the measurement of 2 times had a peak in the upper (plus) component, it was considered as the convex component side.

FIG. 2 is a graph in which the vertical axis represents frequency (%) and the horizontal axis represents height (μm) from the average line for the roughness curve for actual measurement data of Example 4 to be described later. .
FIG. 3 is a graph in which the vertical axis represents frequency (%) and the horizontal axis represents height (μm) from the average line for the roughness curve for actual measurement data of Example 18 described later. It is.
In the case of FIG. 3, the peak position in the frequency distribution diagram of the surface unevenness component is on the plus side (convex component side) from the average line for the roughness curve, and in the case of FIG. 2, the peak position is the roughness curve. It can be seen that it is on the minus side (concave component side) from the average line for. That is, in the present invention (for example, FIG. 2, Example 4), the wetting characteristic is good even if the peak position is on the minus side (concave component side), and the wetting characteristic does not depend on the peak position. In Example 18, the peak position is positive by changing the pickling solution during pickling.

  The measuring method of the surface roughness Ra, Rz is the same as described in Patent Document 2, standard length 1.25 mm, cutoff value 25 mm (conforms to JIS-B0601), scanning speed 0.1 mm / sec. Measure with For the measurement, a surface roughness measuring machine (Surfcoder SE3400) manufactured by Kosaka Laboratory Ltd. is used, the measurement length is 1.25 mm, and the number of measurement data is 7500 points. In addition, surface roughness Ra and Rz were measured 3 times, and the average value was taken.

Next, other rules and compositions of the Co—Si based copper alloy plate of the present invention will be described.
<Composition>
Co: 0.5 to 3.0% by mass, Si: 0.1 to 1.0% by mass, with the balance being Cu and inevitable impurities.
If the content of Co and Si is less than the above range, precipitation strengthening by Co ₂ Si is not sufficient, and the strength cannot be improved. On the other hand, when the content of Co and Si exceeds the above range, the conductivity is deteriorated and the hot workability is also deteriorated. The preferable content of Co is 1.5 to 2.5% by mass, and the more preferable content is 1.7 to 2.2% by mass. The preferable content of Si is 0.3 to 0.7% by mass, and the more preferable content is 0.4 to 0.55% by mass.
The mass ratio of Co / Si is preferably 3.5 to 5.0, more preferably 3.8 to 4.6. If the Co / Si mass ratio is within this range, Co ₂ Si can be sufficiently precipitated.

  Furthermore, one or more selected from the group consisting of Mn, Mg, Ag, P, B, Zr, Fe, Ni, Cr, V, Nb, Mo, Be, Zn, Sn, and Misch metal, It is preferable to contain 2.0% by mass or less. When the total amount of the above elements exceeds 2.0% by mass, the following effects are saturated and productivity is inferior. However, since the effect is small when the total amount of the above elements is less than 0.001% by mass, the total amount of the above elements is preferably 0.001 to 2.0% by mass, more preferably 0.01 to 2.0%. % By mass, most preferably 0.04 to 2.0% by mass.

Here, Mn, Mg, Ag, and P improve the product characteristics such as strength and stress relaxation characteristics without adding conductivity by adding a small amount. These elements mainly exhibit the above-mentioned effects when they are dissolved in the mother phase, but when they are contained in the second-phase particles, further effects are exhibited.
Addition of B, Zr and Fe also improves product properties such as strength, electrical conductivity, stress relaxation properties, and plating properties. The above effects are exerted mainly by dissolving these elements in the mother phase, but by adding them in the second phase particles or forming the second phase particles having a new composition, further effects can be obtained. Is demonstrated.
Ni, Cr, V, Nb, Mo, Be, Zn, Sn, and misch metal complement each other's properties, not only strength and conductivity, but also stress relaxation properties, bending workability, plating properties, and fine ingot structure. It also improves manufacturability such as improvement of hot workability by chemical conversion.
It should be noted that elements not specifically described in the present specification may be added as long as the properties of the alloy of the present invention are not adversely affected.

Next, an example of a method for producing the Co—Si based copper alloy plate of the present invention will be described. First, an ingot made of copper, necessary alloy elements, and inevitable impurities is hot-rolled, face-cut and cold-rolled, solution-treated, and then subjected to aging treatment to precipitate Co ₂ Si. Next, it is finished to a predetermined thickness by final cold rolling, further subjected to strain relief annealing as necessary, finally pickled and immediately buffed.
The solution treatment can be selected, for example, in the range of 700 ° C. or higher and 1000 ° C. or lower. Moreover, an aging treatment can be made into 400 to 650 degreeC for 1 to 20 hours, for example.
The final rolling degree is preferably 5 to 50%, more preferably 20% to 30%. The crystal grain size of the alloy material of the present invention is not particularly limited, but is generally 3 to 20 μm or less. The particle size of the precipitate is 5 nm to 10 μm.

  Cast an ingot having the composition shown in Table 1 and hot-roll at 900 ° C or higher to a thickness of 10mm. After that, an aging treatment was performed at 400 ° C. to 650 ° C. for 1 to 20 hours. Next, it is finished to a predetermined thickness by final cold rolling at a processing rate of 5 to 40%, further subjected to strain relief annealing at 300 to 600 ° C. for 0.05 to 3 hours, and finally pickled under the conditions shown in Table 1. Immediately buffed. The pickling solution used for pickling before buffing is an aqueous solution of dilute sulfuric acid, hydrochloric acid or dilute nitric acid having a concentration of 20 to 30% by mass and pH = 1 or less, and the dipping time for pickling is 60 to 180 seconds. . The buffing material used for the buffing was an alumina abrasive grain and a nylon nonwoven fabric containing alumina. And the buffing material in which the buffing roughness (count of abrasive grains) was changed was used. The count of the abrasive grains indicates the number of meshes per inch of the abrasive grains, and is specified in JIS R6001. For example, if the count is 1000, the average grain size of the abrasive grains is 18 to 14.5 μm. Example 18 is the same as the other examples except that an aqueous solution of nitric acid having a concentration of 40 to 50% by mass and pH = 1 or less was used as the pickling solution for pickling buffing.

Various characteristics of each sample thus obtained were evaluated.
(1) Ra and Rz
According to JIS-B0601 (2001), the center line average roughness Ra and the maximum height Rz were measured. The measurement was performed for the rolling parallel direction (RD) and the rolling perpendicular direction (TD). The standard length is 1.25 mm, the cut-off value is 0.25 mm (conforms to the above JIS), the scanning speed is 0.1 mm / sec, and a surface roughness measuring machine (Surfcoder SE3400) manufactured by Kosaka Laboratory is used. The measurement length was 1.25 mm and the number of measurement data was 7500 points.

(2) Frequency distribution diagram Regarding the measurement data in the direction perpendicular to the rolling obtained in (1), among the measurement data, the upper (plus) component and the lower (minus) component from the “average line for roughness curve” The frequency distribution was plotted with the height from the average line for the roughness curve in increments of 0.05 μm. From the measurement data, the vertical axis is plotted with frequency (%), and the horizontal axis is plotted with the height (μm) from the average line for the roughness curve, and FIGS. 2 and 3 are obtained. 2 and 3, when a line is drawn to 0 μm in height from the average line for the roughness curve on the horizontal axis, whether the frequency peak is a concave component (minus side) or a convex component (plus side), ( Or 0).

(3) Glossiness
The 60-degree specular gloss was determined by using a gloss meter (trade name “PG-1M”, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS Z8741, with an incident angle of 60 for each rolling parallel direction RD and rolling perpendicular direction TD. Measured in degrees.

FIG. 2 is a graph in which actual measurement data of Example 4 is re-plotted with frequency (%) on the vertical axis and height (μm) from the average line for the roughness curve on the horizontal axis.
FIG. 3 is a graph in which the vertical axis represents frequency (%) and the horizontal axis represents height (μm) from the average line for the roughness curve for actual measurement data of Example 18 described later. It is.

(3) Solder characteristics (3-1) Number of pinholes The number of pinholes refers to the number of holes in which the base (copper alloy material) can be seen without solder getting wet. If the number of pinholes increases, soldering defects are likely to occur. The test for the number of pinholes was performed when a 10 mm wide sample was pickled with a 10% by weight dilute sulfuric acid solution, then immersed in a solder bath at an immersion depth of 12 mm, an immersion speed of 25 mm / s, and an immersion time of 10 sec. The front and back sides were observed with an optical microscope (magnification 50 times), and the number of bases that were visually observed was counted.
The solder test was conducted according to JIS-C60068-2-54. The composition of the solder bath was tin 60 wt%, lead 40 wt%, and an appropriate amount of flux (rosin 25 wt%, ethanol 75 wt%) was added to make the solder temperature 235 ° C. ± 3 ° C.
(3-1) Zero cross time (T2 value)
The zero cross time (T2 value) is the time until the wetting stress value becomes zero, and the shorter the zero cross time, the easier it is to get wet with the solder. In the test, the sample was pickled with a 10 wt% dilute sulfuric acid solution, immersed in the above-mentioned solder bath at 235 ° C. ± 3 ° C. at an immersion depth of 4 mm, an immersion speed of 25 mm / s, and an immersion time of 10 sec. The measurement was conducted in accordance with No. 54, and the zero cross time was determined by the meniscograph method. A zero cross time of 2.0 seconds or less was considered good solder wettability.

The obtained results are shown in Tables 1 to 3. In Tables 1 and 2, in “Pre-treatment of finish rolling”, the A method and the B method are pickling buff polishing under the following conditions. For example, in Example 9, pickling buff polishing was performed before finish rolling, and pickling buff polishing was further performed after finish rolling. The pickling liquid used for pickling in the pickling buff polishing before finish rolling is the same as the pickling liquid used for the pickling buff polishing after finish rolling described above.
Method A: Number of times of buffing, one plate speed of 40 m / min, buffing roughness (abrasive grain) of 1000, buffing speed of 500 rpm
Method B: Number of times of buffing 3 times, plate speed 10 m / min, buffing roughness (abrasive grain) 2000, buffing speed 1400 rpm
Note that some samples were only pickled soaking in a 10% aqueous sulfuric acid solution for 30 seconds before finish rolling. In addition, some samples were only degreased soaked in hexane for 30 seconds before finish rolling. Further, the other samples were not subjected to any treatment before finish rolling.

As is clear from Tables 1 to 3, in the case of each Example in which pickling buff polishing after final heat treatment (strain relief annealing) was performed a sufficient number of times using buffs with relatively fine eyes (polishing abrasive grains) Excellent solder wettability and reduced pinholes. In each example, {(60 degree specular gloss G (RD) in the direction parallel to rolling) − (60 degree specular gloss G (TD) in the direction perpendicular to rolling)} ≧ 90%, and the oxide film on the surface of the material It is considered that the indentation of the foreign matter was sufficiently removed and the surface became smooth.
In each example, the pickling buff polishing was performed under the conditions that the abrasive grains were 2000 or more, the number of plate passing was 2 times or more, the plate passing speed was 10 mpm or less, and the number of rotations was 1200 rpm / min. These optimum ranges vary depending on the manufacturing equipment.

  On the other hand, pickling buffing was not sufficiently performed in each comparative example, and the oxide film on the surface of the material and indentation of foreign matters could not be removed sufficiently. Therefore, in each comparative example, {(60-degree specular gloss G (RD) in the direction parallel to rolling)-(60-degree specular gloss G (TD) in the direction perpendicular to rolling)} <90%, which increases pinholes. However, the solder wettability deteriorated when many oxide films remained.

The reason for these deteriorations is considered to be that in the case of Comparative Examples 1, 2, 15, 17, and 19, the plate speed of pickling buffing exceeded 20 mpm.
In the case of Comparative Examples 3, 5, 8, and 20, it is considered that the number of pickling buffing passes is less than two. In Comparative Example 20, pickling was performed by the above-described A method after final rolling.
In the case of Comparative Example 13, it is considered that pickling was performed but buffing was not performed.
In the case of Comparative Examples 6 and 7, it is considered that the effect of reducing Ra (RD) was small because the abrasive grains for pickling buff polishing were set to No. 4000 and the abrasive grains were too fine and not polished much.
In the case of Comparative Examples 11 and 12, it is considered that the rotational speed of pickling buffing is less than 1200 revolutions / minute.
In Comparative Examples 9 and 10, the abrasive grains were too rough and the pickled buffed surface was rough, {(60 degree specular gloss G (RD) in the rolling parallel direction)-(60 degree specular gloss in the direction perpendicular to rolling) G (TD))} <90%, pinholes increased, and zero crossing time worsened. This is presumably because the abrasive grains for pickling buff polishing were set to No. 500 and the abrasive grains were too coarse.
In the case of Comparative Examples 4, 14, 16, 18, and 21, since pickling buffing was not performed after the final rolling, the surface of the rolled surface was maintained without removing the oxide film on the surface and the indentation of foreign matter. Conceivable. In addition, Comparative Example 21 was manufactured in the same manner as each Example except that the roughness of the roll of final rolling was fine.

In Comparative Examples 16 and 18, since the treatment (pickling or degreasing) was performed before finish rolling and the pickling buffing was not performed, the peak line was an average line for the roughness curve (surface unevenness component) It was on the plus side (convex component side) from the zero position in the frequency distribution diagram representing. That is, these comparative examples show copper alloy sheets according to Patent Document 2.
In Comparative Examples 4, 13, 16, and 21, the zero cross time exceeded 2.0 seconds and the solder wettability was deteriorated because the pickling and buffing were not performed once. It is considered that a large amount of was left on the metal surface. (Note that Comparative Example 16 corresponds to the conditions described in Patent Document 2)

The surface roughness Ra (RD) in the rolling parallel direction is preferably 0.08 μm.
It is preferable that the surface roughness Rz (RD) ≦ 0.54 μm in the rolling parallel direction.

Claims (5)

Co: 0.5-3.0% by mass, Si: 0.1-1.0% by mass, the balance being a Co-Si based copper alloy plate made of Cu and inevitable impurities,
{(Co-Si type copper alloy sheet 60% specular gloss G (RD) in the direction parallel to rolling)-(60 degree specular gloss G (TD) in the direction perpendicular to rolling)} ≧ 90%.   The Co-Si based copper alloy sheet according to claim 1, wherein the surface roughness Ra (RD) in the rolling parallel direction is 0.07 µm.   The Co—Si based copper alloy sheet according to claim 2, wherein the surface roughness Rz (RD) ≦ 0.50 μm in the rolling parallel direction.   The Co-Si system according to any one of claims 1 to 3, wherein the peak position in the frequency distribution diagram representing the unevenness component of the surface in the direction perpendicular to the rolling is on the minus side (concave component side) from the average line for the roughness curve. Copper alloy plate.   Further, one or more selected from the group consisting of Mn, Fe, Mg, Ni, Cr, V, Nb, Mo, Zr, B, Ag, Be, Zn, Sn, Misch metal, and P are selected from 2 The Co-Si based copper alloy sheet according to any one of claims 1 to 4, which is contained in an amount of 0.0 mass% or less.

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