TWI453290B - Rolled copper foil - Google Patents

Description

Calendered copper foil

The present invention relates to a rolled copper foil which is suitable for, for example, a flexible printed circuit (FPC) and is suitable for a copper clad laminate.

A flexible wiring board (FPC) is formed by laminating a resin layer and a copper foil, and is preferably used for repeating a bent portion. As the copper foil used in such an FPC, a rolled copper foil excellent in flexibility is widely used. As a method of improving the flexibility of the rolled copper foil, a technique for expanding the cubic aggregate structure after recrystallization annealing has been reported (Patent Document 1). Moreover, as a method of expanding the cubic aggregate structure after recrystallization annealing, a method of specifying the final rolling workability or rolling conditions (Patent Document 2) and a method of retaining the cube orientation after rolling are described (Patent Document 3).

Patent Document 1: Japanese Patent No. 3009383

Patent Document 2: Japanese Laid-Open Patent Publication No. 2009-185376

Patent Document 3: Japanese Laid-Open Patent Publication No. 2010-150597

However, the previous method of expanding the cube assembly organization has the following problem: in order to adjust the final calendering degree, it is necessary to change the thickness of the copper foil material during the final pre-calendering annealing according to the thickness of the final product, or to specialize in the growth of the cube assembly. Calendering or the like is performed under the conditions, whereby productivity is lowered.

Moreover, even if the degree of expansion of the aggregate structure of the cube (the X-ray diffraction intensity of the (200) orientation of the copper foil surface) is the same, the flexibility is not In the same manner, it is difficult to stably obtain a rolled copper foil excellent in flexibility by merely controlling the (200) orientation.

In other words, the present invention has been made to solve the above problems, and an object of the invention is to provide a rolled copper foil obtained by stabilizing flexibility.

As a result of various studies, the inventors have found that not only the (200) orientation of the copper foil, but also the (420) orientation and the (311) orientation of the crystal grains affect the bendability. The crystal grains having the (420) orientation and the (311) orientation are less likely to cause sliding deformation because the stress application direction is close to the sliding direction when bending, and thus the bendability is liable to be lowered.

That is, the integrated intensity I (200) of the X-ray diffraction peak of the (200) plane of the rolled copper foil of the present invention after annealing at 200 ° C for 0.5 hours and the integrated intensity I (311) of the X-ray diffraction peak of the (311) plane The ratio I(311)/I(200) is 0.001 or more and 0.01 or less.

Further, the integrated intensity I (200) of the X-ray diffraction peak of the (200) plane of the rolled copper foil of the present invention after annealing at 200 ° C for 0.5 hours and the integrated intensity I (420) of the X-ray diffraction peak of the (420) plane The ratio I(420)/I(200) is 0.005 or more and 0.02 or less.

Further, the integrated intensity I (200) of the X-ray diffraction peak of the (200) plane of the rolled copper foil of the present invention after annealing at 200 ° C for 0.5 hours and the integrated intensity I (311) of the X-ray diffraction peak of the (311) plane The ratio I (311) / I (200) is 0.001 or more and 0.01 or less, and the integrated intensity I (200) of the (200) plane of the (200) plane after annealing at 200 ° C for 0.5 hours and the X-ray winding of the (420) plane The ratio I(420)/I(200) of the integrated intensity I (420) of the peak is 0.005 or more and 0.02 or less.

The rolled copper foil according to claim 1 or 3 is preferably a ratio I (311)b/ of the integrated intensity I(200)b to I(311)b of the X-ray diffraction peak before final calendering and after recrystallization annealing. I (200)b is formed by final rolling of a copper foil material of 0.01 or more and 0.02 or less.

In the rolled copper foil according to claim 4, it is preferable that when the final rolling workability is η and η=Ln{(thickness before final rolling)/(thickness after final rolling)}, ≧≧2.3.

In the rolled copper foil according to claim 4 or 5, I(311)b/I(200)b/η is preferably 0.1 or more and 0.7 or less.

In the rolled copper foil according to claim 2 or 3, it is preferred that the ratio of the integrated intensity I(200)b to I(420)b of the X-ray diffraction peak before final rolling and after recrystallization annealing is I (420). The copper foil material having b/I (200)b of 0.02 or more and 0.04 or less is finally rolled.

In the rolled copper foil according to claim 7, it is preferable that when the final rolling workability is η and η = Ln { (thickness before final rolling) / (thickness after final rolling)}, ≧≧2.3.

In the rolled copper foil according to claim 7 or 8, it is preferable to set the final rolling degree to η and to represent η=Ln{(thickness before final rolling)/(thickness after final rolling)} In the case, I(420)b/I(200)b/η is 0.5 or more and 1.2 or less.

The rolled copper foil described in claim 3 is preferably formed by final calendering of the following copper foil material: integrated intensity I (200)b and I (311) of the X-ray diffraction peak before final calendering and after recrystallization annealing. b ratio I(311)b/I(200)b is 0.01 or more and 0.02 or less, and before final rolling and then The ratio I (420)b/I(200)b of the integrated intensity I(200)b to I(420)b of the X-ray diffraction peak after crystal annealing is 0.02 or more and 0.04 or less.

In the rolled copper foil according to claim 10, it is preferable that when the final rolling workability is η and η=Ln{(thickness before final rolling)/(thickness after final rolling)}, ≧≧2.3.

In the rolled copper foil according to claim 10 or 11, it is preferable to set the final rolling degree to η and to represent η=Ln{(thickness before final rolling)/(thickness after final rolling)} In the case, I(311)b/I(200)b/η is 0.1 or more and 0.7 or less, and I(420)b/I(200)b/η is 0.5 or more and 1.2 or less.

According to the invention, the rolled copper foil excellent in flexibility can be obtained stably.

Hereinafter, the rolled copper foil according to the embodiment of the present invention will be described.

<Component composition>

As the composition of the copper foil, fine copper (TPC) or JIS-H3100 (C1020) oxygen-free copper (OFC) prescribed in JIS-H3100 (C1100) can be preferably used. Further, it may contain 10 to 500 ppm by mass of Sn, and/or 10 to 500 ppm by mass of Ag as an additive element, and the remainder may be made of refined copper or oxygen-free copper.

In addition, one or more elements including Ag, Sn, In, Ti, Zn, Zr, Fe, P, Ni, Si, Te, Cr, Nb, and V may be contained in an amount of 20 to 500 ppm by mass as an additive element. And the remaining part is set to fine copper or oxygen-free copper.

Furthermore, the rolled copper foil used in the FPC is required to have a bend Therefore, the thickness of the rolled copper foil is preferably 20 μm or less.

<The first aspect of rolled copper foil>

The integrated intensity I (200) of the X-ray diffraction peak of the (200) plane and the integrated intensity I of the X-ray diffraction peak of the (311) plane after annealing of the rolled copper foil of the first aspect of the present invention at 200 ° C for 0.5 hours ( The ratio I(311)/I(200) of 311) is 0.001 or more and 0.01 or less. If the rolled copper foil is annealed at 200 ° C for 0.5 hour, a recrystallized structure is generated, and the cubic aggregate structure is expanded to improve the flexibility of the rolled copper foil. On the other hand, since the crystal grains having the (420) orientation and the (311) orientation after recrystallization are close to the sliding direction due to the stress application direction during bending, it is difficult to cause sliding deformation, so that the bendability is liable to be lowered.

In the above case, if the ratio of the (311) orientation is smaller than the (200) orientation, the bendability can be improved. Therefore, the ratio I(311)/I(200) is set to 0.01 or less. When the ratio I(311)/I(200) exceeds 0.01, the ratio of the (311) orientation increases, and the bendability is lowered. Although the lower the I (311) / I (200), the higher the flexibility, the better, but practically it is a value of 0.001 or more.

Further, the rolled copper foil of the first aspect can be a copper foil material having a ratio of η = 2.3 or more to a ratio of I (311) b / I (200) b before final rolling and after recrystallization annealing of 0.01 or more and 0.02 or less. Final rolling is performed to manufacture.

Here, it is considered that the (420) orientation and the (311) orientation after recrystallization annealing of the copper foil are based on the crystal grains having (420) orientation and (311) orientation existing in the rolled microstructure before recrystallization annealing. And expansion. Moreover, it is considered that the (420) orientation and the (311) orientation in the calendered structure are derived from pre-calendering. organization. That is, before the final rolling and after the recrystallization annealing, by controlling the degree of expansion of the (420) orientation and the (311) orientation, the (420) orientation and (311) after recrystallization annealing of the finally rolled foil can be controlled. Orientation.

In the above case, if the ratio I(311)b/I(200)b before the final rolling and after the recrystallization annealing exceeds 0.02, the crystal grains having the (311) orientation after the final rolling are also largely retained. (311) The ratio of the crystal grains of the orientation is increased, so that sufficient bending property cannot be obtained. On the other hand, when the ratio I(311)b/I(200)b is less than 0.01, the crystal grains are coarsened by annealing, so that sufficient strain cannot be applied by final rolling, and the foil after final rolling is applied. A case where sufficient bendability cannot be obtained after recrystallization annealing.

When the final rolling degree is less than η = 2.3, there is a case where sufficient strain cannot be applied by final rolling, and sufficient bending property cannot be obtained after recrystallization annealing of the finally rolled foil.

In the rolled copper foil according to the first aspect, I(311)b/I(200)b/η is preferably 0.1 or more and 0.7 or less. Further, I(311)b/I(200)b/η is preferably 0.1 or more and 0.5 or less.

In general, in the manufacturing process of the copper foil, since the degree of processing of the final calendering process is high, even if the structure before the final rolling is controlled, the influence of the structure tends to be sufficiently retained until the rolling. Therefore, by controlling the degree of processing of the structure before final rolling and the final rolling, sufficient flexibility can be obtained.

If I(311)b/I(200)b/η exceeds 0.5, there are a large number of grains having a (311) orientation after the final rolling, and there is a (311) orientation. The proportion of the crystal grains is increased, so that sufficient bending property cannot be obtained. The lower the ratio of I(311)b/I(200)b/η, the higher the flexibility and the better, but practically it is a value of 0.05 or more.

<The second aspect of rolled copper foil>

The integrated intensity I (200) of the X-ray diffraction peak of the (200) plane and the integrated intensity I of the X-ray diffraction peak of the (420) plane after annealing the copper foil of the second aspect of the present invention at 200 ° C for 0.5 hours ( The ratio I(420)/I(200) of 420) is 0.005 or more and 0.02 or less.

As described above, since the crystal grains having the (420) orientation and the (311) orientation after recrystallization are close to the sliding direction when the stress is applied, it is difficult to cause sliding deformation, so that the bendability is liable to be lowered. In other words, if the ratio of the (420) orientation is smaller than the (200) orientation, the bendability can be improved. Therefore, the ratio I(420)/I(200) is set to 0.02 or less. When the ratio I(420)/I(200) exceeds 0.02, the ratio of the (420) orientation increases, and the bendability is lowered. However, if the ratio I(420)/I(200) is less than 0.005, the ratio of the (200) orientation becomes too large, and sufficient flexibility can be obtained, but the handleability is lowered because the copper foil is too soft.

Further, the rolled copper foil of the second aspect can have a ratio of workability of η = 2.3 or more to a ratio of I (420)b / I (200)b before final rolling and after recrystallization annealing, and is 0.02 or more and 0.04 or less. The copper foil material is produced by final rolling.

If the ratio I(420)b/I(200)b before the final calendering and after the recrystallization annealing exceeds 0.04, there are a large number of crystal grains having a (420) orientation after the final rolling, and the crystal has a (420) orientation. The proportion of the granules is increased, so that sufficient flexibility cannot be obtained. On the other hand, Yu I(420)b/I When (200)b is less than 0.02, the crystal grains are coarsened by annealing, so that sufficient strain cannot be applied by final rolling, and sufficient bending property cannot be obtained after recrystallization annealing of the finally rolled foil. .

In the rolled copper foil of the second aspect, I(420)b/I(200)b/η is preferably 0.5 or more and 1.2 or less. Further, I(420)b/I(200)b/η is more preferably 0.5 or more and 1.0 or less.

Here, the crystal grains having the (420) orientation as the recrystallized structure are rotated by the calendering process to form crystal grains having other orientations. Therefore, when the degree of calendering is high, the ratio of the (420) plane is reduced, and I(420) is lowered. On the other hand, in the case where the degree of processing is low, the crystal grains having a (420) orientation tend to remain, and I (420) tends to become high.

In the above case, if I(420)b/I(200)b/η exceeds 1.0, there are a large number of crystal grains having a (420) orientation after the final rolling, and the crystal grains have a (420) orientation. The proportion is increased, so that sufficient flexibility cannot be obtained. Further, when I(420)b/I(200)b/η is less than 0.5, sufficient flexibility can be obtained, but the copper foil is too soft and the handleability is lowered.

<Manufacture of rolled copper foil>

The rolled copper foil of the first and second aspects can be produced by subjecting the ingot to hot rolling, followed by rolling before annealing, recrystallization annealing, and final rolling. Here, the stability of the recrystallization orientation is in the order of (200) > (311) > (420), and the higher the temperature rise rate in the recrystallization annealing, the more unstable (420) orientation and (311) orientation increase. The tendency. Therefore, it is preferred to set the temperature increase rate during recrystallization annealing to 5 to 50 ° C / s, so that the speed ratio is known. Slow.

Moreover, it is preferable to set the workability of η=1.6 or more after rolling before annealing, and to set the crystal grain size after recrystallization annealing and before final rolling to 10 μm or more and 30 μm or less. In the case of annealing conditions in which the crystal grain size before final rolling is 10 μm or less, there is a high possibility that residual non-recrystallized structure remains. Further, when the crystal grain size before the final rolling exceeds 30 μm, sufficient strain cannot be applied by final rolling, and sufficient bending property cannot be obtained after recrystallization annealing of the finally rolled foil.

Further, as described above, the final rolling can be performed with a degree of work of η = 2.3 or more.

Further, the crystal grain size was measured by a cutting method of JIS H0501.

Example

First, a copper ingot having the composition described in Table 1 was produced and hot rolled until the thickness became 10 mm. Thereafter, annealing and calendering were repeated, and after calendering to a specific thickness, it was subjected to recrystallization annealing through a continuous annealing furnace at 750 °C. Further, the final cold rolling was carried out at the degree of work shown in Table 1, and copper foil having the thickness shown in Table 1 was obtained. Further, the rate of temperature rise at the time of recrystallization annealing is shown in Table 1.

<degree of orientation>

After the copper foil obtained by the final rolling was annealed at 200 ° C for 0.5 hour to recrystallize, the (200) plane, the (311) plane, and the (420) plane obtained by X-ray diffraction of the calendering surface were respectively determined. The integral value of the intensity (I).

Further, the integrated intensities of the X-ray diffraction peaks of the (200) plane, the (311) plane, and the (420) plane before the final calendering and after the recrystallization annealing were respectively determined. The value is As in I(200)b, it is indicated by adding "b".

<bending>

After the copper foil sample obtained by final rolling was heated at 200 ° C for 30 minutes to recrystallize, the bending fatigue life was measured by the bending test apparatus shown in FIG. 1 . This device has a structure in which the vibration transmitting member 3 is coupled to the vibration driving body 4, and the test copper foil 1 is fixed to the device by a total of four points at the front end portion of the screw 2 and the three end portions indicated by the arrows. When the vibrating portion 3 is driven up and down, the intermediate portion of the copper foil 1 is bent into a hairpin shape with a specific radius of curvature r. In this test, the number of times until the fracture was repeated under the following conditions was determined.

Furthermore, the test conditions are as follows, the test piece width: 12.7 mm, the test piece length: 200 mm, and the test piece selection direction: the length direction of the test piece is parallel to the rolling direction, the radius of curvature r: 1.5 mm, the vibration stroke : 20 mm, vibration speed: 1000 times / minute.

Further, the flexibility was evaluated on the basis of the following criteria. When the evaluation is ◎, ○, or Δ, the bendability is good.

◎: The bending times are more than 200,000 times, and the bending is best.

○: The number of bending is 100,000 times or more and less than 200,000 times, and the bending property is good.

△: The number of bending is 50,000 times or more and less than 100,000 times, and the bending property is excellent.

×: The number of bending is less than 50,000 times, and the bending is poor.

The results obtained are shown in Tables 1 and 2.

Here, "TPC" in the composition column in Table 1 indicates the refined copper (TPC) specified in JIS-H3100 (C1100), and "OFC" indicates JIS-H3100. Oxygen-free copper (OFC) as specified in (C1020). Therefore, for example, "190 ppm Ag-TPC" in the composition column of Table 1 means a composition in which 190 mass ppm of Ag is added to the refined copper (TPC) specified in JIS-H3100 (C1100). In addition, "100 ppm of Sn-OFC" in the composition column of Table 1 means a composition in which 100 mass ppm of Sn is added to oxygen-free copper (OFC) prescribed in JIS-H3100 (C1020).

As is apparent from Table 1, when I (311) / I (200) is 0.001 or more and 0.01 or less, or I (420) / I (200) is 0.005 or more and 0.02 or less, the flexibility is excellent. In particular, when I (311) / I (200) is 0.001 or more and 0.01 or less, and I (420) / I (200) is 0.005 or more and 0.02 or less, in the case of Examples 1 to 12 and 15 to 21, and Example 13 14 is more excellent than bending.

On the other hand, in the case of Comparative Examples 1 to 3 in which I(311)/I(200) exceeded 0.01 and I(420)/I(200) exceeded 0.02, the flexibility was poor.

Further, as apparent from Table 2, in the case of each of the examples, I(311)b/I(200)b is 0.01 or more and 0.02 or less, or I(311)b/I(200)b/η is 0.1 or more. 0.7 or less. Further, in the case of each of the examples, I(420)b/I(200)b is 0.02 or more and 0.04 or less, or I(420)b/I(200)b/η is 0.5 or more and 1.2 or less. In particular, in the case of Examples 1 to 12 and 15 to 21, I(311)/I(200) is 0.001 or more and 0.01 or less, and I(420)/I(200) is 0.005 or more and 0.02 or less, and the flexibility is particularly excellent. .

On the other hand, in the case of Comparative Examples 1 to 3, I(311)b/I(200)b exceeded 0.02 and I(311)b/I(200)b/η exceeded 0.7. Similarly, in the case of Comparative Examples 1 to 3, I(420)b/I(200)b exceeded 0.04, and I(420)b/I(200)b/η exceeded 1.2.

1‧‧‧Tested copper foil

2‧‧‧ screws

3‧‧‧Vibration transmission member (vibration part)

4‧‧‧Vibration driver

Fig. 1 is a view showing a method of measuring a bending fatigue life by a bending test apparatus.

1‧‧‧Tested copper foil

2‧‧‧ screws

3‧‧‧Vibration transmission member (vibration part)

4‧‧‧Vibration driver

Claims (12)

A ratio of the integrated intensity I (200) of the X-ray diffraction peak of the (200) plane to the integrated intensity I (311) of the X-ray diffraction peak of the (311) plane after annealing at 200 ° C for 0.5 hour. (311) / I (200) is 0.001 or more and 0.008 or less. A ratio of the integrated intensity I (200) of the X-ray diffraction peak of the (200) plane and the integrated intensity I (420) of the X-ray diffraction peak of the (420) plane after annealing at 200 ° C for 0.5 hour. (420) / I (200) is 0.005 or more and 0.02 or less. A ratio of the integrated intensity I (200) of the X-ray diffraction peak of the (200) plane to the integrated intensity I (311) of the X-ray diffraction peak of the (311) plane after annealing at 200 ° C for 0.5 hour. (311) / I (200) is 0.001 or more and 0.01 or less, and the integrated intensity I (200) of the (200) plane X-ray diffraction peak after annealing at 200 ° C for 0.5 hours and the X-ray diffraction peak of the (420) plane The ratio I (420) / I (200) of the integrated intensity I (420) is 0.005 or more and 0.02 or less. A rolled copper foil according to claim 1 or 3, which is a ratio of the integrated intensity I(200)b to I(311)b of the X-ray diffraction peak before final calendering and after recrystallization annealing, I(311) The copper foil material having b/I (200)b of 0.01 or more and 0.02 or less is finally rolled. The rolled copper foil according to claim 4, wherein the final calendering degree is η, and η = Ln { (thickness before final rolling) / (thickness after final rolling)}, η ≧2.3. For example, the rolled copper foil of the fourth application patent scope, wherein I(311) b/I(200)b/η is 0.1 or more and 0.7 or less. A rolled copper foil according to claim 2 or 3, which is a ratio of the integrated intensity I(200)b to I(420)b of the X-ray diffraction peak before final calendering and after recrystallization annealing, I(420) The copper foil material having b/I (200)b of 0.02 or more and 0.04 or less is finally rolled. The rolled copper foil according to item 7 of the patent application, wherein the final calendering degree is η, and η=Ln{(thickness before final rolling)/(thickness after final rolling)}, η ≧2.3. The rolled copper foil according to item 7 of the patent application, wherein the final calendering degree is η, and η=Ln{(thickness before final rolling)/(thickness after final rolling)}, (420) b/I (200) b / η is 0.5 or more and 1.2 or less. The rolled copper foil according to item 3 of the patent application is formed by final calendering of the following copper foil material: integrated intensity I (200)b and I of the X-ray diffraction peak before final calendering and after recrystallization annealing ( 311)b ratio I(311)b/I(200)b is 0.01 or more and 0.02 or less, and the integrated intensity I(200)b and I(420)b of the X-ray diffraction peak before final calendering and after recrystallization annealing The ratio I(420)b/I(200)b is 0.02 or more and 0.04 or less. The rolled copper foil according to claim 10, wherein the final calendering degree is η, and η=Ln{(thickness before final rolling)/(thickness after final rolling)}, η ≧2.3. A rolled copper foil according to claim 10 or 11, wherein the final calendering degree is η, and η = Ln { (before final rolling) When the thickness is / (the thickness after final rolling)}, I(311)b/I(200)b/η is 0.1 or more and 0.7 or less, and I(420)b/I(200)b/η is 0.5 or more. 1.2 or less.