JP2008088499A - Copper alloy sheet superior in press stampability for electric and electronic parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Cu-Fe-P-based copper alloy sheet having both high strength and excellent press stampability. <P>SOLUTION: The Cu-Fe-P-based copper alloy sheet has a particular composition, has a tensile elasticity exceeding 120 GPa, which is determined by a tensile test, and has a ratio of uniform elongation to total elongation expressed by uniform elongation/total elongation of less than 0.50 to decrease a shear plane rate when measured in such a way as shown in the figure. Thus manufactured copper alloy sheet acquires high strength and improved press stampability in a stamping process. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a Cu-Fe-P-based copper alloy plate having high strength and excellent press punchability during stamping, for example, a copper alloy plate suitable as a material for a lead frame for a semiconductor device. In addition to lead frames for semiconductor devices, the copper alloy plate of the present invention can be used for various electrical components such as other semiconductor components, electrical / electronic component materials such as printed wiring boards, switchgear components, bus bars, mechanical components such as terminals / connectors. It is suitably used for electronic parts. However, in the following description, as a typical application example, the description will be focused on the case where it is used for a lead frame which is a semiconductor component.

  As a copper alloy for a semiconductor lead frame, a Cu—Fe—P based copper alloy containing Fe and P has been generally used. 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, along with the increase in capacity, size, and functionality of semiconductor devices used in electronic devices, lead frames used in semiconductor devices have become smaller in cross-sectional area, resulting in greater strength, conductivity, and thermal conductivity. Is required. Accordingly, copper alloy plates used for lead frames used in these semiconductor devices are required to have higher strength and thermal conductivity.

  On the other hand, these high-strength copper alloy plates are also required to be workable into the lead frame having a small cross-sectional area. Specifically, since the copper alloy plate is stamped into a lead frame, the copper alloy plate is required to have excellent press punchability. This requirement is the same in applications other than lead frames in which a copper alloy plate is processed by stamping.

  In the Cu-Fe-P-based copper alloy sheet, conventionally, means for improving the press punchability are conventionally means for controlling a chemical component such as addition of a small amount of Pb, Ca or the like, or dispersing a compound that is a starting point of fracture, Means for controlling the crystal grain size and the like have been widely used.

  However, these means have problems such as difficulty in control itself, deterioration of other characteristics, and hence an increase in manufacturing cost.

  On the other hand, focusing on the structure of the Cu—Fe—P-based copper alloy plate, it has been proposed to improve press punchability and bending workability. For example, Patent Document 1 includes Fe: 0.005 to 0.5 wt%, P: 0.005 to 0.2 wt%, and further Zn: 0.01 to 10 wt%, Sn: 0.01 as necessary. A Cu—Fe—P-based copper alloy plate comprising any one or both of ˜5 wt% and comprising the remaining Cu and inevitable impurities is disclosed. And in patent document 1, the press punching property is improved by controlling the accumulation degree of the crystal orientation of this copper alloy plate (refer patent document 1).

  More specifically, in Patent Document 1, the degree of integration is controlled by reintegrating the copper alloy plate and increasing the crystal grain size of the structure to increase the integration ratio of {200} and {311} planes on the plate surface. Is increased by increasing the accumulation ratio of {220} planes when rolled. Characteristically, with respect to the {200} and {311} planes, the stamping performance is improved by increasing the accumulation ratio of {220} planes on the plate surface. More specifically, the X-ray diffraction intensity from the {200} plane on this plate surface is I [200], the X-ray diffraction intensity from the {311} plane is I [311], and the X-ray from the {220} plane. When the diffraction intensity is I [220], the equation [I [200] + I [311]] / I [220] <0.4 is satisfied.

  In Patent Document 2, in order to improve press punchability, the ratio of the X-ray diffraction intensity I (200) of the (200) plane of the copper alloy plate to the X-ray diffraction intensity I (220) of the (220) plane, 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: It has been proposed that the ratio of D (Cube orientation) to S orientation: D (S orientation): D (Cube orientation) / D (S orientation) is 0.1 or more and 5 or less (Patent Literature) 2).

  Moreover, in patent document 3, in order to improve the bending workability of a Cu-Fe-P type copper alloy plate, the sum of (200) plane X-ray diffraction intensity and (311) plane X-ray diffraction intensity, It has been proposed that the ratio [I (200) + I (311)] / I (220) to the (220) plane X-ray diffraction intensity is 0.4 or more (see Patent Document 3).

  Further, Patent Document 4 proposes that I (200) / I (110) be 1.5 or less in order to improve the flexibility of the Cu-Fe-P-based copper alloy plate (Patent Document). 4).

Moreover, in order to improve the bending workability of the Cu—Ni—Si based copper alloy (Corson alloy) plate, although it is another copper alloy type, the uniform elongation and the total elongation of the tensile properties of the copper alloy plate It is known that the ratio is 0.5 or more (see Patent Document 5).
JP 2000-328158 A JP 2002-339028 A JP 2000-328157 A JP 2006-63431 A JP 2002-266042 A

  In Patent Documents 1 and 2 described above, the stamping performance is improved by increasing the accumulation ratio of {220} planes and {200} planes on the plate surface. By increasing the accumulation ratio of these specific surfaces, the press punchability of the Cu—Fe—P based copper alloy plate is certainly improved.

  However, the reduction of the cross-sectional area of the lead frame has progressed further, and the lead width (0.5 mm → 0.3 mm) and plate thickness (0.25 mm → 0.15 mm) have become smaller and higher in strength. The demand for improving the press punchability at the time of stamping to an Fe-P based copper alloy plate is becoming more severe. For this reason, the press punchability improvement effect by the structure accumulation ratio control as described in Patent Documents 1 and 2 does not satisfy the required press punchability.

  Further, the means for improving the bending workability of the copper alloy plate as described in Patent Document 5 cannot improve the required press punchability. The object of Patent Document 5 is a Cu—Ni—Si based copper alloy (Corson alloy) having a 0.2% proof stress of 800 MPa level and a conductivity of 40% IACS level, and the Cu—Fe—P based copper of the present invention. The alloy system and properties are completely different from the alloy. Further, the bending workability and the press punching property are completely different characteristics. When the ratio of the uniform elongation to the total elongation is 0.5 or more as in Patent Document 5, the present invention will be described later. The press punchability of the Cu—Fe—P-based copper alloy decreases.

  The present invention has been made in order to solve the problem of the Cu-Fe-P-based copper alloy, in which such an increase in strength and an improvement in press punchability are not compatible, and the object is to increase the strength. The object is to provide a Cu-Fe-P-based copper alloy sheet having both excellent press punchability.

  In order to achieve this object, the summary of the copper alloy sheet for electrical and electronic parts of the present invention excellent in press punchability is mass%, Fe: 0.01 to 0.50%, P: 0.01 to 0.00. Each containing 15%, consisting of the remainder Cu and unavoidable impurities, and determined by a tensile test of a test piece taken with the plate width direction orthogonal to the rolling direction as the longitudinal direction, the tensile modulus exceeds 120 GPa, The ratio of uniform elongation to total elongation, uniform elongation / total elongation is less than 0.50.

  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.

  It is preferable that the copper alloy sheet of the present invention is further restricted to S: 20 ppm or less and Pb: 20 ppm or less.

  The copper alloy sheet of the present invention preferably has a tensile strength of 500 MPa or more and a hardness of 150 Hv or more as a measure of high strength. The electrical conductivity correlates with the strength of the plate, and the high electrical conductivity referred to in the present invention means that the electrical conductivity is relatively high for the high strength.

  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%. Further, in addition to these, or in place of these, one or two or more of Zr, Ag, Cr, Cd, Be, Ti, Co, Ni, Au, and Pt in total are 0% in total. 0.001 to 1.0% may be contained.

  The copper alloy plate of the present invention further includes Hf, Th, Li, Na, K, Sr, Pd, W, Si, Nb, Al, V, Y, Mo, In, Ga, Ge, As, Sb, Bi, Te. , B and the content of misch metal are 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.

  In the present invention, in a Cu-Fe-P-based copper alloy plate having a tensile strength increased to 500 MPa or more, the tensile modulus and uniformity obtained by a tensile test rather than a texture control as in Patent Documents 1 and 2 are uniform. It has been found that tensile properties such as the ratio of elongation to total elongation greatly affect the press punchability.

  The press punchability improves as the tensile modulus determined by the tensile test increases. Further, the press punching property is improved as the ratio of the uniform elongation to the total elongation is smaller. However, these tensile properties defined in the present invention are, at present, the structure of the Cu—Fe—P-based copper alloy sheet, that is, the state of precipitates (such as the amount of precipitates and the size of the precipitates) or the texture. The clear correlation of is unknown. Therefore, in the present invention, as a requirement for improving the press punchability, the structure of the Cu—Fe—P based copper alloy sheet is difficult to define both qualitatively and quantitatively.

  In addition, these tensile properties defined in the present invention are naturally greatly affected by the component composition of the Cu-Fe-P copper alloy sheet, but are also greatly affected by the manufacturing method and conditions, and are not determined only by the component composition. . That is, these tensile properties defined in the present invention are, as described later, the Cu-Fe-P-based copper alloy sheet, the homogenization heat treatment or heat treatment before hot rolling, the water cooling start temperature after hot rolling, and the intermediate annealing. It is greatly influenced by the manufacturing method and conditions such as the temperature and the plate passing speed during the last continuous annealing.

  In addition, these tensile properties defined in the present invention are difficult to obtain by batch-type final annealing, but can be obtained only by continuous annealing in which a plate (coil) is processed while being continuously passed through a furnace. It ’s hard.

  For this reason, in the present invention, in order to ensure good press punchability of the Cu-Fe-P-based copper alloy plate, together with the component composition, as described above, the tensile elastic modulus, the ratio of uniform elongation to total elongation, etc. The Cu—Fe—P-based copper alloy plate is defined by the tensile properties of

  In the following, the significance and embodiments of each requirement in the Cu—Fe—P based copper alloy sheet of the present invention for satisfying the required characteristics, such as for semiconductor lead frames, will be specifically described.

(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. Then, satisfactory press punchability is achieved after satisfying these basic characteristics or on the assumption that these basic characteristics are not deteriorated. 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.

  In the present invention, elements such as Zn and Sn described later may be further selectively contained in the 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 content of Fe is too small, depending on the production conditions, the amount of the precipitated particles produced is small and the improvement in conductivity is satisfied, but the contribution to strength improvement is insufficient and the strength is insufficient. On the other hand, when there is too much content of Fe, electrical conductivity and Ag plating property will fall. Therefore, in order to increase the conductivity forcibly, an attempt to increase the amount of precipitation of the precipitated particles leads to growth and coarsening of the precipitated particles. For this reason, the strength and the tensile properties defined in the present invention are not satisfied, and the press punchability is reduced. 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 desired strength cannot be obtained because the precipitation of the compound is insufficient depending on the production conditions. On the other hand, when the P content is too large, not only the conductivity is lowered, but also the tensile properties defined in the present invention are not satisfied, and the hot workability and the press punching property are lowered. Therefore, the P content is in the range of 0.01 to 0.15%, preferably 0.05 to 0.12%.

(Zn)
Zn improves the heat-resistant peelability of copper alloy solder and Sn plating required for lead frames and the like. 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). Select from a range of 0%.

(Sn)
Sn contributes to improving the strength of the copper alloy. 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). It is supposed to be selected and 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.

(S, Pb)
In the copper alloy plate of the present invention, it is further preferable to restrict S to 20 ppm or less and Pb: 20 ppm or less. S and Pb inhibit basic characteristics such as strength, hardness, and conductivity for a semiconductor lead frame, and also inhibit Ag plating properties.

(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.

(Tensile properties of the plate)
In the present invention, on the premise of the component composition as described above, by a tensile test of a test piece taken with the plate width direction (perpendicular direction) orthogonal to the rolling direction of the Cu-Fe-P-based copper alloy plate as the longitudinal direction. The required tensile properties such as the tensile modulus and the ratio between uniform elongation and total elongation are defined as described above, and the good punching property of the Cu—Fe—P based copper alloy sheet is ensured.

(Tensile modulus)
First, the tensile elastic modulus (Young's modulus) calculated | required by the tensile test of a Cu-Fe-P type copper alloy plate shall be over 120 GPa. The larger the tensile elastic modulus, the smaller the accumulated strain with respect to the stress applied to the plate during press punching. For this reason, at the time of press punching, the punching break occurs at an early stage, the shear surface ratio is reduced, and the press punching property is improved.

  On the other hand, if the tensile elastic modulus is as low as 120 GPa or less, the amount of accumulated strain with respect to the stress applied to the plate at the time of press punching increases, and the shear surface ratio increases without causing punching breakage. descend.

  Although the reason why the tensile modulus of elasticity is as low as 120 GPa or less is conceivable, in particular, in a Cu-Fe-P-based copper alloy plate, during the homogenization heat treatment or heat treatment before hot rolling described later, Insufficient homogenization of the plate structure (the plate structure is non-uniform), the water cooling start temperature after hot rolling is too low, or the final annealing is performed in batch or continuous final annealing. This is mainly the case when the plate speed is low.

(Uniform elongation / total elongation)
Next, the ratio of uniform elongation to total elongation, uniform elongation / total elongation, obtained by a tensile test of the Cu—Fe—P based copper alloy plate is set to less than 0.50. The greater the uniform elongation / total elongation is 0.50 or more, in other words, the greater the ratio of uniform elongation to the total elongation, the more the plate (material) undergoes ductile deformation during press punching. For this reason, the amount of deformation of the plate up to the fracture of punching increases, the shear surface ratio increases, and the press punching performance decreases. On the other hand, if the uniform elongation / total elongation is less than 0.50, the punching breaks at an early stage during press punching, the shear surface ratio is reduced, and the press punching property is improved.

  The reason why the uniform elongation / total elongation becomes larger than 0.50 is that the Cu-Fe-P-based copper alloy sheet has a particularly insufficient amount of precipitates in the sheet structure because the water cooling start temperature after hot rolling is too high. The intermediate annealing temperature is too high, so that material recovery / recrystallization progresses too much, the intermediate annealing time is too short and the amount of precipitates in the plate structure is insufficient, or the final annealing is performed in batch or continuous annealing. Even so, the plate passing speed is slow.

(Tensile test)
The tensile test conditions for determining (measuring) the tensile elastic modulus and the ratio between the uniform elongation and the total elongation are performed under the following test conditions for reproducibility. The test piece is a JIS No. 5 tensile test piece. From the obtained (manufactured) Cu—Fe—P-based copper alloy plate, a tensile test piece having a direction perpendicular to the rolling direction as its longitudinal direction is taken. An extensometer is attached after fixing this test piece to a testing machine, and a tensile test is performed at a tensile speed of 10.0 mm / min (a constant speed until the test piece breaks). As the tester, it is preferable to use a 5882 type universal tester manufactured by Instron.

  The tensile strength is obtained from the numerical value obtained by measurement with a testing machine, and the total elongation is obtained by abutting the test pieces after the test and measuring the distance between the scores. Moreover, a tensile elasticity modulus and uniform elongation are calculated | required from the numerical value obtained with the said extensometer.

(Production method)
Next, preferable manufacturing conditions for bringing the copper alloy plate within the range specified in the present invention will be described below. As described above, the tensile modulus defined in the present invention and the ratio between uniform elongation and total elongation are naturally greatly influenced by the component composition of the Cu-Fe-P-based copper alloy plate, but depending on the production method and conditions. Is greatly affected and cannot be determined by the composition of the ingredients alone. In this respect, in order to obtain tensile properties such as the tensile modulus as defined above in the present invention and the ratio between uniform elongation and total elongation, a homogenized heat treatment of the Cu-Fe-P-based copper alloy plate, The manufacturing method and conditions such as the water cooling start temperature after hot rolling, the intermediate annealing temperature, and the sheet feeding speed during the last continuous annealing are controlled as described below.

  That is, first, a molten copper alloy adjusted to the composition of the present invention is cast. Melting / casting is performed by a normal method such as continuous casting or semi-continuous casting. In order to regulate the above-described S and Pb, it is preferable to use a copper-melting raw material having a small S and Pb content. Prior to homogenization heat treatment or heat treatment of the ingot, chamfering is performed by a conventional method.

(Homogenization heat treatment or heat treatment)
When the homogenization of the ingot before hot-rolling or during the heat treatment is insufficiently homogenized (the plate structure is not uniform), the finally obtained Cu-Fe-P-based copper alloy sheet structure is also obtained. Not only becomes non-uniform and the strength decreases, but also the tensile elastic modulus becomes as low as 120 GPa or less. For this reason, it is preferable to perform the homogenization heat treatment or heat treatment of the ingot at least at a temperature of 900 ° C. or more for 2 hours or more depending on the thickness and size of the ingot.

(Hot rolling)
Hot rolling is started at a temperature of 900 ° C. or higher, and water cooling of the hot rolled plate is started from a temperature range of 700 to 800 ° C. after the hot rolling is finished. If the water cooling start temperature after the hot rolling is higher than 800 ° C., the water cooling start temperature is too high and precipitates in the plate structure are not generated, and the amount of precipitates is insufficient. For this reason, the ratio of the uniform elongation to the total elongation is increased, and the ratio of the uniform elongation to the total elongation does not become less than 0.50.

  On the other hand, even if the water cooling start temperature after the hot rolling is lower than 700 ° C., the crystal grains are excessively refined and the tensile elastic modulus is lowered, and the ratio of uniform elongation to the total elongation is increased. The ratio of elongation to total elongation is not less than 0.50. Further, since coarse precipitates are generated, the strength is lowered.

  After the hot rolling, the water-cooled plate is further subjected to primary cold rolling, which is said to be intermediate rolling, annealing, washing, and further finishing (final) cold rolling, final annealing (low temperature annealing, finish annealing), A copper alloy plate with 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.

(Intermediate annealing)
In the above process, the intermediate annealing conditions also greatly affect the uniform elongation / total elongation. Suitable intermediate annealing conditions for setting the ratio of uniform elongation to total elongation to less than 0.50 are performed at a temperature of 430 ° C. or lower for 5 hours or longer. If this intermediate annealing temperature is too high, not only the recovery / recrystallization of the material proceeds too much and the strength decreases, but also the ratio of uniform elongation to total elongation increases, and the ratio of uniform elongation to total elongation is 0.50. Not less than. If this intermediate annealing time is too short, the amount of precipitates in the plate structure is insufficient and the conductivity is lowered.

(Final annealing)
In the above process, the final annealing conditions also greatly affect the tensile modulus and uniform / total elongation. In order to obtain a Cu-Fe-P copper alloy sheet having a tensile modulus exceeding 120 GPa and a ratio of uniform elongation to total elongation of less than 0.50, the sheet (coil) is continuously placed in the furnace. Therefore, it is necessary to perform continuous annealing while processing the sheet.

  In addition, in order to obtain this characteristic, it is necessary to control the sheet 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, not only does the strength decrease, but the ratio of the uniform elongation to the total elongation increases, and the ratio between the uniform elongation and the total elongation does not become less than 0.50. Also, the tensile modulus cannot exceed 120 GPa. 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 the batch type final annealing, for the same reason that the plate passing speed in the continuous annealing is too slow, the tensile elastic modulus in the tensile test specified as described above in the present invention, uniform elongation and total elongation This ratio cannot be obtained.

  Examples of the present invention will be described below. Cu-Fe-P-based copper alloy thin plates were produced by changing the production conditions such as homogenization heat treatment, water cooling start temperature after hot rolling, intermediate annealing temperature, and plate passing speed during final continuous annealing. Then, tensile properties such as the tensile modulus of elasticity and the ratio between uniform elongation and total elongation, or properties such as tensile strength, hardness, conductivity, and shear surface ratio of each of these copper alloy thin plates were evaluated. These results are shown in Table 2.

  Specifically, the copper alloy melts having the chemical composition shown in Table 1 are melted using a coreless furnace which is an atmospheric melting furnace, and cast with a thickness of 70 mm × width 200 mm × length 500 mm by a semi-continuous casting method. A lump was obtained.

  The surface of each ingot is chamfered, heated and soaked under the conditions shown in Table 2 (temperature × time), and then hot-rolled at a temperature of 950 ° C. to form a plate having a thickness of 16 mm. Quenched into water from the indicated starting temperature. Next, after removing the oxide scale, primary cold rolling (intermediate rolling) was performed. After chamfering the plate, final cold rolling is performed in which four passes of cold rolling are performed while intermediate annealing is performed at a temperature shown in Table 2 for 10 hours, and a thickness of 0.15 mm corresponding to thinning of the lead frame is performed. A copper alloy plate was obtained. This copper alloy plate was subjected to final annealing in which continuous annealing was performed at a temperature of 350 ° C. at a sheeting speed shown in Table 2 to obtain a product copper alloy plate.

  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, Si, Nb, The content of Al, V, Y, Mo, In, Ga, Ge, As, Sb, Bi, Te, B, and misch metal was 0.1% by mass or less in total of these elements.

  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, In the case of one or more of Ni, Au, and Pt, 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. did.

  With respect to the copper alloy plate thus obtained, in each example, a test piece (sample) was cut out from the copper alloy plate with the plate width direction orthogonal to the rolling direction as the longitudinal direction, and the tensile modulus of each sample and The ratio between uniform elongation and total elongation, or properties such as tensile strength, hardness, electrical conductivity, and shear surface ratio were evaluated. These results are shown in Table 2, respectively.

(Shear area ratio measurement)
The press punchability is evaluated based on the shear surface ratio (shear surface ratio) of the cross section of the lead provided by press punching simulating the lead punching of the copper alloy plate. If this shearing area ratio is 75% or less, it can be evaluated that the press punchability is good. The evaluation based on the shearing area ratio can more accurately evaluate the required press punchability than the press punchability evaluation test in which a lead is punched into a copper alloy plate and the flash height at that time is measured.

  In the press punching test, as shown in FIG. 1, by using a punching press (clearance: 5%), a lead having a width of 1 mm × a length of 10 mm was used with a copper alloy sheet (G-6316 made by Nippon Kogyo Oil) The test piece 1) is sequentially punched as a punching hole 2 whose longitudinal direction is the plate width direction orthogonal to the rolling direction indicated by the arrow.

  As a result, the center of the punched hole 2 is cut along the length direction (the cut portion is indicated by a broken line 3), the cut surface of the punched hole 2 is observed from the direction of the arrow 4 and cut using an optical microscope. It was obtained by image analysis from the surface photograph of the surface. The shear rate is the area ratio of the shear plane in the cut plane (the area of the shear plane / the area of the cut plane). The area of the cut plane is the thickness of the copper alloy sheet 0.15 mm × measured width 0.5 mm, The area was the area of the shear plane within the measurement width of 0.5 mm. Three holes were punched out for each sample, and three holes were measured for each hole (total of 9 points), and the average value was obtained.

(Hardness measurement)
The hardness of the copper alloy plate sample was measured at an arbitrary three locations of the sample by applying a load of 0.5 kg with a micro Vickers hardness meter, and the hardness was calculated as an average value thereof.

(Conductivity measurement)
The electrical conductivity of the copper alloy sheet 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 electric resistance with a double bridge type resistance measuring device.

  As is apparent from Tables 1 and 2, Invention Examples 1 to 11, which are copper alloys within the composition of the present invention, have a component composition within the scope of the present invention, and water cooling start temperature after homogenization heat treatment and hot rolling. The production conditions such as the plate passing speed during the last continuous annealing are produced within a preferable range. For this reason, Invention Examples 1 to 11 have tensile properties in which the tensile modulus exceeds 120 GPa and the uniform elongation / total elongation is less than 0.50.

  As a result, the inventive examples 1 to 11 have a relatively high electrical conductivity for a high strength of 500 MPa or higher and a hardness of 150 Hv or higher, and a shear surface area of 75% or lower. Also, it has excellent press punchability.

  However, Invention Example 3 in which the Fe content is close to the lower limit and Invention Example 5 in which the P content is close to the lower limit are relatively low in strength compared to the other Invention Examples 1 and 2. Inventive Example 4 in which the Fe content is close to the upper limit, and Inventive Example 6 in which the P content is close to the upper limit, the shear surface ratio is relatively high and the conductivity is higher than those of the other Inventive Examples 1 and 2. Relatively low.

  On the other hand, Comparative Examples 12 to 17 are copper alloys within the same composition of the present invention as in Invention Example 1, but homogenization heat treatment, water cooling start temperature after hot rolling, plate passing speed during final continuous annealing, and the like. The production conditions are out of the preferred range. For this reason, Comparative Examples 12 to 17 have a tensile modulus of elasticity as low as 120 GPa or less, or uniform elongation / total elongation as too high as 0.50 or more. As a result, Comparative Examples 12 to 17 have a shear surface area exceeding 75%, and the press punchability is extremely inferior.

  In Comparative Example 12, the time for the homogenization heat treatment is too short. In Comparative Example 13, the temperature during the homogenization heat treatment is too low. In Comparative Example 14, the water cooling start temperature after hot rolling is too high. In Comparative Example 15, the water cooling start temperature after hot rolling is too low. In Comparative Example 16, the intermediate annealing temperature is too high. In Comparative Example 17, the sheet passing speed during the last continuous annealing is too slow.

  Although the copper alloys of Comparative Examples 18 to 21 are manufactured under preferable conditions, the component composition is out of the scope of the present invention. For this reason, Comparative Examples 18 to 21 have a tensile modulus of elasticity as low as 120 GPa or less, or uniform elongation / total elongation as too high as 0.50 or more. As a result, Comparative Examples 18 to 21 have a shear surface ratio exceeding 75%, and the press punchability is extremely inferior.

  In Comparative Example 18, the Fe content is lower than the lower limit of 0.01%. For this reason, the shear surface ratio is high, the press punchability is inferior, and high strength cannot be achieved.

  In Comparative Example 19, the Fe content is higher than the upper limit of 5.0%. For this reason, the shear surface ratio is high, the press punchability is inferior, and high strength cannot be achieved.

  In the copper alloy of Comparative Example 20, the P content is slightly lower than the lower limit of 0.01%. For this reason, the shear surface ratio is high, the press punchability is inferior, and the high strength cannot be achieved.

  In the copper alloy of Comparative Example 21, the P content is higher than the upper limit of 0.15%. For this reason, cracks occurred during hot rolling.

  From the above results, the critical significance of the tensile properties such as the component composition, tensile elastic modulus, uniform elongation / total elongation, etc. of the copper alloy sheet of the present invention for enhancing the strength and improving the press punchability. And the significance of preferable manufacturing conditions for obtaining such tensile properties 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 press punchability and has both of these characteristics (combined), while having high strength. it can. As a result, high-strength and severe bending workability is required for lead frames, connectors, terminals, switches, relays, etc., in addition to semiconductor device lead frames, for miniaturized and lightweight electrical and electronic components. It can be applied for use.

It is explanatory drawing which shows the measuring method of a shearing area rate.

Explanation of symbols

1: Copper alloy plate, 2: Punched hole, 3: Cut part

Claims (9)

  In mass%, Fe: 0.01 to 0.50%, P: 0.01 to 0.15%, each of which consists of the balance Cu and unavoidable impurities, the sheet width direction orthogonal to the rolling direction A press characterized by a tensile elastic modulus exceeding 120 GPa and a ratio of uniform elongation to total elongation, uniform elongation / total elongation of less than 0.50, which is obtained by a tensile test of a specimen taken as a longitudinal direction. Copper alloy sheet for electrical and electronic parts with excellent punchability.   The copper alloy plate according to claim 1, wherein the copper alloy plate further contains Sn: 0.005 to 5.0% by mass.   The copper alloy plate according to claim 1 or 2, wherein the copper alloy plate further contains Zn: 0.005 to 3.0% by mass.   The copper alloy plate for electric and electronic parts according to any one of claims 1 to 3, wherein the copper alloy plate is further regulated to S: 20 ppm or less and Pb: 20 ppm or less.   The copper alloy plate for electrical and electronic parts according to any one of claims 1 to 4, wherein the copper alloy plate has a tensile strength of 500 MPa or more and a hardness of 150 Hv or more.   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 copper alloy plate for electrical and electronic parts according to any one of claims 1 to 5.   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 7. The copper alloy plate for electrical and electronic parts according to any one of Items 1 to 6.   The copper alloy plate is Hf, Th, Li, Na, K, Sr, Pd, W, Si, Nb, Al, V, Y, Mo, In, Ga, Ge, As, Sb, Bi, Te, B, The copper alloy plate for electrical and electronic parts according to any one of claims 1 to 7, wherein the content of misch metal is 0.1% by mass or less in total of all of these elements.   The copper alloy plate for electrical and electronic parts according to claim 1, wherein the copper alloy plate is for a semiconductor lead frame.

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