JP2008127605A - High-strength copper alloy sheet superior in bend formability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Cu-Fe-P-based copper alloy sheet having both of high strength and excellent bend formability, for use in electric and electronic parts and the like. <P>SOLUTION: The Cu-Fe-P-based copper alloy sheet having improved bend formability has such enhanced strength as a tensile strength of 500 MPa or higher and a hardness of 150 Hv or higher even though containing a comparatively small amount of Fe, and has an r-value controlled to 0.3 or higher in a parallel direction to a rolling direction of the copper alloy sheet. Then, the copper alloy sheet acquires enhanced reliability as a base metal of a semiconductor for use in miniaturized and lightweighted electric and electronic parts and the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a copper alloy having high strength and excellent bending workability, for example, semiconductor parts such as lead frames for semiconductor devices, electrical / electronic parts materials such as printed wiring boards, switchgear parts, bus bars, terminals, The present invention relates to a copper alloy plate suitable as a copper alloy material strip used for mechanical parts such as connectors.

  As a copper alloy for the above-mentioned various uses including those for semiconductor lead frames, a Cu-Fe-P-based copper alloy (also referred to as a Cu-Fe-P-based alloy) containing Fe and P has been widely used. Has been. Examples of these Cu-Fe-P-based copper alloys include, for example, a copper alloy containing Fe: 0.05 to 0.15% and P: 0.025 to 0.040% (C19210 alloy), Fe: 2 An example is a copper alloy (CDA194 alloy) containing 0.1 to 2.6%, P: 0.015 to 0.15%, and Zn: 0.05 to 0.20%. These Cu-Fe-P-based copper alloys are excellent in strength, conductivity and thermal conductivity among copper alloys when an intermetallic compound such as Fe or Fe-P is precipitated in the copper matrix. Therefore, it is widely used as an international standard alloy.

  In recent years, with the expansion of Cu-Fe-P-based copper alloys and the reduction in weight, thickness, and size of electrical and electronic equipment, these copper alloys have even higher strength, electrical conductivity, and superior bending. Workability is required. Such bending workability is required to be capable of severe bending such as contact bending or 90 ° bending after notching.

  On the other hand, it has been conventionally known that bending workability can be improved to some extent by refining crystal grains or controlling the dispersion state of crystals and precipitates (see Patent Documents 1 and 2).

  It has also been proposed to control the texture in order to improve various properties such as bending workability in Cu—Fe—P based alloys. More specifically, the ratio of the X-ray diffraction intensity I (200) of the (200) plane and the X-ray diffraction intensity I (220) of the (220) plane of the copper alloy plate, I (200) / I ( 220) is 0.5 or more and 10 or less, or orientation density of Cube orientation: D (Cube orientation) is 1 or more and 50 or less, or orientation density of Cube orientation: D (Cube orientation) It has been proposed that a ratio of orientation density of S orientation: D (S orientation): D (Cube orientation) / D (S orientation) is 0.1 or more and 5 or less (see Patent Document 3).

Furthermore, the sum of the (200) plane X-ray diffraction intensity I (200) and the (311) plane X-ray diffraction intensity I (311) and the (220) plane X-ray diffraction intensity I ( 220), [I (200) + I (311)] / I (220) is proposed to be 0.4 or more (see Patent Document 4).
JP-A-6-235035 JP 2001-279347 A JP 2002-339028 A JP 2000-328157 A

  Bending workability inevitably deteriorates with the addition of solid solution strengthening elements such as Sn and Mg, which has been a means of increasing the strength of copper alloys, and by increasing the work hardening amount due to strong processing due to an increase in the processing rate of cold rolling. Therefore, it is difficult to achieve both necessary strength and bending workability. However, in order to obtain a high-strength Cu-Fe-P-based alloy having a tensile strength of 500 MPa or more that can cope with recent reductions in the thickness of electrical and electronic parts, processing by such strong processing of cold rolling. Increase in the amount of curing is essential.

  For such a high-strength Cu—Fe—P alloy, the structure control means such as crystal grain refinement, crystal / precipitate dispersion state control as described in Patent Documents 1 and 2, and the patent With only texture control means such as Documents 3 and 4, bending workability cannot be sufficiently improved with respect to severe bending such as contact bending or 90 ° bending after notching.

  The present invention has been made to solve such problems, and it is an object of the present invention to provide a Cu—Fe—P-based copper alloy sheet having both high strength and excellent bending workability.

  In order to achieve this object, the gist of the high-strength copper alloy sheet excellent in bending workability of the present invention is mass%, Fe: 0.01 to 0.50%, P: 0.01 to 0.15. %, And the balance Cu and inevitable impurities, the tensile strength is 500 MPa or more, the hardness is 150 Hv or more, the r value in the direction parallel to the rolling direction of the copper alloy plate It shall be 0.3 or more.

  In order to achieve high strength, the copper alloy plate of the present invention further contains 0.005 to 5.0% Sn by mass, or further improves the heat-resistant peelability of solder and Sn plating. % 0.005 to 3.0% Zn may be contained.

  The copper alloy sheet of the present invention may further contain 0.0001 to 1.0% of one or more of Mn, Mg, and Ca in total by mass%.

  The copper alloy sheet of the present invention is further in mass%, and one or more of Zr, Ag, Cr, Cd, Be, Ti, Co, Ni, Au, and Pt are added in a total amount of 0.001 to 1.0. % May be contained.

  The copper alloy sheet of the present invention is further in mass%, and 0.001 to 1.0% in total of one or more of Mn, Mg, and Ca, Zr, Ag, Cr, Cd, Be, Ti In addition, 0.001 to 1.0% in total of one or more of Co, Ni, Au, and Pt, respectively, and the total content of these elements as 1.0% or less, It may be contained.

  The copper alloy plate of the present invention further includes Hf, Th, Li, Na, K, Sr, Pd, W, S, Si, C, Nb, Al, V, Y, Mo, Pb, In, Ga, Ge, As. , Sb, Bi, Te, B, misch metal content is preferably 0.1% by mass or less in total of these elements.

  The copper alloy plate of the present invention can be applied to various electric and electronic parts, but is particularly preferably used for a semiconductor lead frame which is a semiconductor part.

  The present invention is a high-strength copper alloy plate having a tensile strength of 500 MPa or more, wherein the r value in the direction parallel to the rolling direction of the Cu-Fe-P-based copper alloy plate is a constant value of 0.3 or more. Even improve the bending workability.

  Here, in the field of steel plates and aluminum alloy plates other than copper, it is known that the r value is improved and the bending workability is improved even with high strength steel plates and aluminum alloy plates. However, in copper alloys, particularly Cu—Fe—P based copper alloy plates, it has not always been known to improve bending workability by paying attention to the r value.

  This is because, in the field of Cu-Fe-P-based copper alloy sheets as in the prior art described above, in order to improve bending workability, crystal grain refinement, crystal / precipitate dispersion state control, and aggregation This is presumably because the control of the crystal orientation distribution density of the copper alloy sheet, such as the control of the structure, was the mainstream. Moreover, in the Cu—Fe—P based copper alloy plate, there is a common sense that elements other than the r value are greatly affected by the improvement of the bending workability, and the r value is not so effective in improving the bending workability. It is also inferred from the reason.

  As described above, unlike other Corson alloys and the like, Cu-Fe-P-based copper alloy sheets that have a large limit on the content of solid solution strengthening elements inevitably increase the strength of the cold rolling process rate. It must be done by increasing the amount of work hardening by strong processing due to the increase.

  In this cold rolling strong processing, naturally, the crystal grain size has a large anisotropy of the crystal orientation which is elongated (longer) in the rolling direction. For this reason, in particular, it is known that the bending workability in the direction parallel to the rolling direction is significantly reduced. Therefore, in order to improve the bending workability, naturally, the large anisotropy of the crystal orientation, which is a major cause of the decrease in bending workability, that is, controlling the crystal orientation distribution density of the copper alloy plate, Of great interest among those skilled in the art.

  However, it is very difficult to control the crystal orientation distribution density of such a copper alloy sheet to control each crystal orientation to a desired distribution density in order to obtain a desired bending workability. .

  On the other hand, in this invention, the r value of a Cu-Fe-P type copper alloy plate is improved, and even if it is a high strength copper alloy plate, bending workability is improved. The r value is also referred to as a plastic strain ratio, and indicates a reduction rate of the material width and thickness in a tensile test of a material such as a Cu—Fe—P copper alloy plate. The r value increases when the ratio of the reduction in the plate thickness to the reduction in the plate width of the material is small. In this respect, the bending workability also becomes better as the rate of reduction of the plate thickness with respect to the reduction of the plate width of the material is smaller. Therefore, as a material such as a Cu—Fe—P-based copper alloy plate, the larger the r value is, It is difficult to break and the bending workability is improved.

  On the other hand, the correlation or the consequence of the bending workability and the r value, on the other hand, is an index representing the plastic anisotropy as is well known, and is closely related to the crystal orientation distribution density. Is also supported.

  However, as described above, even if there is a correlation between the bending workability and the r value in the Cu-Fe-P-based copper alloy sheet, as described above, the bending workability is merely improved to the r value. Whether it is effective or not is a completely different problem. Further, whether or not the r value can be improved only by improving the bending workability is another problem. That is, improving the r value and improving the bending workability in the Cu—Fe—P-based copper alloy plate is a problem that cannot be understood unless it is actually performed.

  In this regard, in the present invention, as will be described later, the low temperature annealing after the cold rolling is performed by continuous annealing, and at this time, an appropriate tension is applied to the plate in the plate by a special method (means) or the like. The r value in the direction parallel to the rolling direction of the -Fe-P-based copper alloy sheet is set to a certain value of 0.3 or more. And even if it is a high intensity | strength copper alloy board whose tensile strength is 500 Mpa or more, bending workability is improved.

(R value)
In the present invention, as described above, in order to improve the bending workability of the Cu—Fe—P-based copper alloy plate having a tensile strength of 500 MPa or more and a hardness of 150 Hv or more, the direction parallel to the rolling direction of the copper alloy plate R value of 0.3 or more.

  As described above, in the Cu-Fe-P-based copper alloy sheet that is strengthened by increasing the work hardening amount due to the strong processing by increasing the processing rate of the cold rolling, the crystal grain size is increased (longer) in the rolling direction. It has large anisotropy of crystal orientation.

  As a result, in the Cu-Fe-P copper alloy sheet after cold rolling, the r value in the direction perpendicular to the rolling direction is inevitably higher than the r value in the direction parallel to the rolling direction. .

  In the use of the above-described lead frame or the like of the Cu-Fe-P-based copper alloy plate of the present invention, the bending process is exclusively a bending process parallel to the rolling direction, that is, the Good Way (the bending axis is in the rolling direction). A right angle bend is performed.

  Therefore, in the present invention, in order to improve this Good Way bending, the r value on the parallel direction side with respect to the rolling direction of the copper alloy sheet, which inevitably decreases the r value, is defined. In other words, if the r value on the inevitably low side (in the direction parallel to the rolling direction of the copper alloy sheet) is increased by the cold rolling for increasing the strength, the r on the side that inevitably increases. The value (perpendicular to the rolling direction) is higher.

  For example, if the r value in the direction parallel to the rolling direction of the copper alloy sheet is set to 0.3 or more, the r value in the direction perpendicular to the rolling direction is inevitably increased to about 0.4 or more.

(R value measurement)
For the r value in the direction parallel to the rolling direction of the copper alloy plate, a tensile test is performed by preparing a JIS No. 5 test piece so that the direction parallel to the rolling direction is the longitudinal direction of the test piece. For reproducibility, the tensile test is performed at a constant tensile speed of 10 mm / min after fixing a JIS No. 5 test piece to a tensile tester and then attaching an extensometer.

In order to obtain the r value as a plastic strain ratio from the rate of reduction of the plate width and thickness of the material between 0 point and 0.5% strain, the longitudinal elastic gauge value L (initial value L ₀ ) Using the directional elastic gauge value W (initial value W ₀ ) or the like, the calculation is performed by the following equation.
r value = In (W / W ₀ ) / [In (L / L ₀ ) −In (W / W ₀ )]

(Component composition of copper alloy sheet)
In the present invention, it is necessary to have basic characteristics such as high strength with a tensile strength of 500 MPa or more and hardness of 150 Hv or more for a semiconductor lead frame. And it has the outstanding plating property which prevents abnormal precipitation of plating, on the assumption that these basic characteristics are not deteriorated while satisfying these basic characteristics. For this reason, the Cu-Fe-P-based copper alloy sheet is in mass%, the Fe content is in the range of 0.01 to 0.50%, and the P content is in the range of 0.01 to 0.15%. The basic composition consisting of the remaining Cu and inevitable impurities.

  You may further selectively contain elements, such as Zn and Sn mentioned later, with respect to this basic composition. Further, elements other than those described (impurity elements) are allowed to be contained within a range that does not impair the characteristics of the present invention. In addition, all the indication% of content of these alloy elements and impurity elements means the mass%.

(Fe)
Fe is a main element that precipitates as Fe or an Fe-based intermetallic compound and improves the strength and heat resistance of the copper alloy. If the Fe content is too small, the contribution to strength improvement is insufficient, and the improvement in electrical conductivity is satisfied, but the strength is insufficient even if the final cold rolling is performed on the strong working side. On the other hand, if the Fe content is too large, the electrical conductivity is lowered. Furthermore, since the amount of crystallized substances increases and becomes the starting point of fracture, the strength and heat resistance are also lowered, and the bending workability is lowered for the strength. Therefore, the Fe content is 0.01 to 0.50%, preferably 0.15 to 0.35%.

(P)
In addition to deoxidizing action, P is a main element that forms a compound with Fe to increase the strength of the copper alloy. If the P content is too small, the precipitation of the compound is insufficient, so the contribution to strength improvement is insufficient and the improvement in conductivity is satisfied, but even if the final cold rolling is performed on the strong working side, the strength Is lacking. On the other hand, when there is too much P content, not only electrical conductivity will fall, but hot workability will fall and it will become easy to produce a crack. Therefore, the P content is in the range of 0.01 to 0.15%, preferably 0.05 to 0.12%.

(Zn)
Zn is a selective additive element for improving the heat-resistant peelability of the copper alloy solder and Sn plating necessary for the lead frame and the like, and when these effects are required. If the Zn content is less than 0.005%, the desired effect cannot be obtained. On the other hand, if it exceeds 3.0%, not only the solder wettability is lowered but also the conductivity is greatly lowered. Therefore, the Zn content in the case of selective inclusion is 0.005 to 3 depending on the balance between the electrical conductivity required for the application and the heat resistance peelability of the solder and Sn plating (in consideration of the balance). It is supposed to be contained selectively from the range of 0.0%.

(Sn)
Sn contributes to improving the strength of the copper alloy, and is a selective additive element when these effects are necessary. When the Sn content is less than 0.001%, it does not contribute to high strength. On the other hand, when the Sn content is increased, the effect is saturated, and conversely, the conductivity is lowered. Accordingly, the Sn content in the case of selective inclusion is in the range of 0.001 to 5.0% depending on the balance between strength (hardness) and conductivity required for the application (in consideration of the balance). To be selectively contained.

(Mn, Mg, Ca content)
Since Mn, Mg and Ca contribute to the improvement of hot workability of the copper alloy, they are selectively contained when these effects are required. When the content of one or more of Mn, Mg, and Ca is less than 0.0001% in total, a desired effect cannot be obtained. On the other hand, if the total content exceeds 1.0%, coarse crystals or oxides are generated, not only reducing the strength and heat resistance, but also reducing the conductivity. Therefore, the content of these elements is selectively contained in the range of 0.0001 to 1.0% in total.

(Zr, Ag, Cr, Cd, Be, Ti, Co, Ni, Au, Pt amount)
Since these components have an effect of improving the strength of the copper alloy, they are selectively contained when these effects are required. When the content of one or more of these components is less than 0.001% in total, the desired effect cannot be obtained. On the other hand, if the total content exceeds 1.0%, coarse crystallized substances and oxides are generated, which not only lowers the strength and heat resistance, but also causes a significant decrease in conductivity, which is not preferable. Therefore, the content of these elements is selectively contained in the range of 0.001 to 1.0% in total. In addition, when these components are contained with the said Mn, Mg, and Ca, the total content of these contained elements shall be 1.0% or less.

(Hf, Th, Li, Na, K, Sr, Pd, W, Si, Nb, Al, V, Y, Mo, In, Ga, Ge, As, Sb, Bi, Te, B, Misch metal)
These components are impurity elements, and when the total content of these elements exceeds 0.1%, coarse crystallized products and oxides are formed, and the strength and heat resistance are lowered. Therefore, the total content of these elements is preferably 0.1% or less.

(Production conditions)
Next, preferable manufacturing conditions for making the copper alloy sheet structure the structure defined in the present invention will be described below. The copper alloy sheet of the present invention can be produced in the same process as that of a conventional method, except that the usual production process itself is not greatly changed except for the preferable final low temperature continuous annealing condition described later for controlling the r value.

  That is, first, a molten copper alloy adjusted to the preferred component composition is cast. Then, after chamfering the ingot, it is heated or homogenized and then hot-rolled, and the hot-rolled plate is water-cooled. This hot rolling may be performed under normal conditions.

  After that, the first cold rolling, which is said to be intermediate, is annealed, washed, and then finished (final) cold rolled and low-temperature annealed (final annealing, final annealing) to obtain a copper alloy sheet having a product thickness. . These annealing and cold rolling may be repeated. For example, in the case of a copper alloy plate used for a semiconductor material such as a lead frame, the product plate thickness is about 0.1 to 0.4 mm.

  In addition, you may perform the solution treatment of a copper alloy plate, and the quenching process by water cooling before primary cold rolling. At this time, the solution treatment temperature is selected from a range of 750 to 1000 ° C., for example.

(Final cold rolling)
Final cold rolling is also according to conventional methods. However, as described above, in order to obtain a high strength with a tensile strength of 500 MPa or more and a hardness of 150 Hv or more in a Cu—Fe—P based copper alloy plate having a large limit in the content of the solid solution strengthening element, The processing rate of the final cold rolling is determined on the strong processing side in relation to the processing rate of the cold rolling up to.

  In addition, it is preferable that the minimum rolling reduction (cold rolling ratio) per pass of final cold rolling shall be 20% or more. If the minimum rolling reduction per pass of this final cold rolling is lower than 20%, the compressive force generated in the width direction of the plate is small, so that the plate thickness strain increases and the r value does not increase.

(Final annealing)
The final low temperature annealing condition after the final cold rolling greatly affects the r value in the direction parallel to the rolling direction of the Cu—Fe—P based copper alloy sheet. In this respect, in the present invention, in order to control the r value in the direction parallel to the rolling direction of the Cu—Fe—P based copper alloy sheet and to make it 0.3 or more, this low temperature annealing is performed by continuous annealing. At this time, an appropriate tension in the range of 0.1 to 8 kgf / mm ² is applied to the plate in the plate. Thereby, the tensile compression deformation with a small plate | board thickness change is given. The r value of the plate increases due to the plastic deformation.

If this tension is too small and less than 0.1 kgf / mm ² , depending on the equipment conditions and the plate thickness, the tension applied to the plate is insufficient and parallel to the rolling direction of the Cu—Fe—P copper alloy plate. The r value in the direction does not exceed 0.3. In addition, when the tension is too large and exceeds 8 kgf / mm ² , depending on the equipment conditions and plate thickness, in the thin product plate thickness range of 0.1 to 0.4 mm, the plate in the through plate is It becomes easy to break.

  This final low-temperature continuous annealing condition greatly affects basic properties such as strength and elongation in addition to the r value. In this respect, in the present invention, in order to obtain characteristics such as elongation, the final continuous annealing condition in this continuous heat treatment furnace should be a low temperature condition of 100 to 400 ° C. and not less than 0.2 minutes and not more than 300 minutes. preferable. In the manufacturing method of the copper alloy plate used for a normal lead frame, since the strength is lowered, the final annealing is not performed after the final cold rolling except for annealing for removing strain (about 350 ° C. × 20 seconds). However, in the present invention, this strength reduction is suppressed by lowering the temperature of the final annealing. And bending workability etc. improve by performing final annealing at low temperature.

  Under conditions where the continuous annealing temperature is lower than 100 ° C, the annealing time is less than 0.2 minutes, or the conditions where this low-temperature annealing is not performed, the structure and properties of the copper alloy sheet are from the state after the final cold rolling. Most likely not changed. Conversely, if annealing is performed at a temperature exceeding 400 ° C. or annealing time exceeding 300 minutes, recrystallization occurs, rearrangement of dislocations and recovery phenomenon occur excessively, and precipitates also become coarse. For this reason, there is a high possibility that the press punchability and the strength are lowered.

  Moreover, it is preferable to control the plate-feeding speed in the continuous annealing in the range of 10 to 100 m / min. If the plate passing speed is too slow, material recovery / recrystallization proceeds excessively. For this reason, strength and elongation decrease. However, due to equipment limitations (capacity limits) in the continuous annealing furnace and the possibility of plate breakage, it is not necessary to increase the plate passing speed beyond 100 m / min.

  On the other hand, in batch-type final annealing, tension cannot be applied to the plate during annealing, and the r value in the direction parallel to the rolling direction of the Cu—Fe—P-based copper alloy plate is not improved. In addition, basic characteristics such as strength and elongation cannot be obtained for the same reason that the sheet passing speed in continuous annealing is too slow.

  Examples of the present invention will be described below. As shown in Table 2, Cu-Fe-P-based copper alloy thin plates having the respective chemical composition shown in Table 1 were produced by changing only the tension conditions of the plate during the final low-temperature annealing. And the r value and bending workability of the parallel direction with respect to the rolling direction of each copper alloy sheet were evaluated. These results are shown in Table 2.

  Specifically, after each copper alloy having the chemical composition shown in Table 1 was melted in a coreless furnace, it was ingoted by a semi-continuous casting method, and the ingot was 70 mm thick × 200 mm wide × 500 mm long. Got. The surface of each ingot was chamfered and heated, and then hot-rolled to form a plate having a thickness of 16 mm, and rapidly cooled into water from a temperature of 650 ° C. or higher. Next, after removing the oxide scale, primary cold rolling (intermediate rolling) was performed. After chamfering the plate, cold rolling was performed with intermediate annealing, followed by final low-temperature annealing at 400 ° C. to obtain a copper alloy plate having a thickness of 0.15 mm corresponding to the thinning of the lead frame.

  Table 2 shows the minimum rolling reduction per pass in the final cold rolling and the tension applied to the plate during the final low-temperature annealing. In this way, the r value in the direction parallel to the rolling direction of each copper alloy sheet is controlled by variously changing only the minimum rolling reduction per pass in final cold rolling and the tension condition of the plate during final low temperature annealing. did.

  In each of the copper alloys shown in Table 1, the remaining composition excluding the described element amount is Cu, and other impurity elements are Hf, Th, Li, Na, K, Sr, Pd, W, S, Si, The content of C, Nb, Al, V, Y, Mo, Pb, In, Ga, Ge, As, Sb, Bi, Te, B, and misch metal is 0.1% by mass or less in total of these elements. Met.

  Further, when one or more of Mn, Mg, and Ca are included, the total amount is in the range of 0.0001 to 1.0 mass%, and Zr, Ag, Cr, Cd, Be, Ti, Co, When one or more of Ni, Au, and Pt are included, the total amount is in the range of 0.001 to 1.0% by mass, and the total amount of these elements is also 1.0% by mass or less. It was.

  In each example, a sample was cut out from the obtained copper alloy plate, and a tensile test, conductivity measurement, and a bending test were performed. These results are also shown in Table 2.

(Tensile test)
The tensile test was performed under the conditions of r value measurement described above using a 5882 type Instron universal testing machine under the conditions of room temperature, test speed 10.0 mm / min, GL = 50 mm, tensile strength, 0.2% proof stress. The r value was measured.

(Conductivity measurement)
The electrical conductivity of the copper alloy plate sample was calculated by an average cross-sectional area method by processing a strip-shaped test piece having a width of 10 mm and a length of 300 mm by milling, measuring the electrical resistance with a double bridge type resistance measuring device.

(Evaluation test for bending workability)
The bending test of the copper alloy sheet sample was performed according to the Japan Copper and Brass Association technical standard. The plate material was cut into a width of 10 mm and a length of 30 mm, and the presence or absence of cracks in the bent portion was observed with a 50 × optical microscope while bending the Good Way (the bending axis was perpendicular to the rolling direction). And ratio R / t of minimum bending radius R which a crack does not produce, and board thickness t (0.15mm) of a copper alloy board was calculated | required. The smaller this R / t, the better the bending workability. However, since the bending workability inevitably decreases as the strength increases, in the case of a copper alloy plate used for a semiconductor material such as a lead frame, R / t is less than 1.5 at a hardness of 150 to 200 Hv, It is calculated | required that it is less than 2.0 at 200 Hv or more. Incidentally, less than 150 Hv is low hardness (low strength) outside the scope of the present invention, but R / t is required to be less than 0.5 below 150 Hv.

  As is apparent from Tables 1 and 2, Invention Examples 1 to 13, which are copper alloys within the composition of the present invention, have high strength with a tensile strength of 500 MPa or more and a hardness of 150 Hv or more. In addition, since the inventive examples 1 to 13 apply a preferable tension to the plate during the final continuous annealing, the r value in the direction parallel to the rolling direction of the copper alloy thin plate is 0.3 or more. Therefore, Invention Examples 1 to 13 are excellent in bending workability as a semiconductor base material.

  On the other hand, Comparative Examples 14 and 15 do not apply tension to the plate during the last continuous annealing. As a result, Comparative Examples 14 and 15 are copper alloys within the composition of the present invention, and despite the high strength of tensile strength of 500 MPa or more and hardness of 150 Hv or more, relative to the rolling direction of the copper alloy sheet. The r value in the parallel direction is less than 0.3. Therefore, Comparative Examples 14 and 15 are inferior in bending workability as a semiconductor base material.

  In Comparative Example 16, the Fe content falls below the lower limit of 0.01% and the strength level is low, and in this respect, the r value in the direction parallel to the rolling direction of the copper alloy sheet is 0.3 or more. However, it cannot be used as a semiconductor base material.

  In Comparative Example 17, the upper limit of the Fe content is 5.0%, and the bending workability is inferior to the strength. Further, even when compared with the same strength level example of the inventive example, the electrical conductivity may be remarkably low for the strength, so that it cannot be used as a semiconductor base material.

  In Comparative Example 18, the content of P deviates slightly from the lower limit of 0.01%, and the strength level is low. In this respect, the r value in the direction parallel to the rolling direction of the copper alloy sheet is 0.3 or more. However, it cannot be used as a semiconductor base material.

  In Comparative Example 19, since the P content was higher than the upper limit of 0.15% and cracking occurred during hot rolling, the trial production was stopped at that time.

  In Comparative Example 20, the minimum rolling reduction per pass of the final cold rolling is less than 20%. For this reason, although it is a copper alloy within the composition of the present invention, the r value in the direction parallel to the rolling direction of the copper alloy sheet is less than 0.3, and the bending workability is poor.

  From the above results, the component composition of the copper alloy sheet of the present invention, the critical significance of the r-value definition, and further the r-value and high-strength for improving the bending workability after increasing the strength. The significance of preferable production conditions for obtaining the above is supported.

  As described above, according to the present invention, it is possible to provide a Cu—Fe—P-based copper alloy sheet that is excellent in bending workability and has both of these characteristics (combined), while having high strength. it can. As a result, a highly reliable semiconductor base material can be provided. Therefore, for electrical and electronic parts that are reduced in size and weight, besides lead frames for semiconductor devices, such as lead frames, connectors, terminals, switches, relays, etc., for applications that require high strength and bending workability. Can be applied.

Claims (8)

  It is a copper alloy plate containing Fe: 0.01 to 0.50%, P: 0.01 to 0.15%, and the balance Cu and unavoidable impurities, and has a tensile strength of 500 MPa or more. A high-strength copper alloy plate excellent in bending workability, characterized in that the hardness is 150 Hv or more and the r value in the direction parallel to the rolling direction of the copper alloy plate is 0.3 or more.   The high-strength copper alloy plate according to claim 1, wherein the copper alloy plate further contains Sn: 0.005 to 5.0% by mass.   The high-strength copper alloy plate according to claim 1, wherein the copper alloy plate further contains Zn: 0.005 to 3.0% by mass.   4. The copper alloy sheet according to claim 1, further comprising 0.0001 to 1.0% of one or more of Mn, Mg, and Ca in total by mass%. 5. High strength copper alloy plate.   The copper alloy plate is further 0.001 to 1.0% in total of one or more of Zr, Ag, Cr, Cd, Be, Ti, Co, Ni, Au, and Pt in mass%. The high-strength copper alloy plate according to any one of claims 1 to 4, which is contained.   The copper alloy plate is further, by mass%, one or more of Mn, Mg, and Ca in a total of 0.0001 to 1.0%, Zr, Ag, Cr, Cd, Be, Ti, One or two or more of Co, Ni, Au, and Pt are respectively added in a total amount of 0.001 to 1.0%, and the total content of these elements is 1.0% or less. Item 6. The high-strength copper alloy sheet according to any one of Items 1 to 5.   The copper alloy plate is Hf, Th, Li, Na, K, Sr, Pd, W, S, Si, C, Nb, Al, V, Y, Mo, Pb, In, Ga, Ge, As, Sb, The high-strength copper alloy sheet according to any one of claims 1 to 6, wherein the content of Bi, Te, B, and Misch metal is 0.1% by mass or less in total of these elements.   The high-strength copper alloy plate according to any one of claims 1 to 7, wherein the copper alloy plate is for a semiconductor lead frame.