JP2020504231A - Electrical and electronic components having high strength and high electrical conductivity characteristics, copper alloys for semiconductors, and methods of manufacturing the same - Google Patents

Abstract

The present invention relates to an electric / electronic component having high strength and high electric conductivity, a copper alloy for a semiconductor, and a method for producing the same. In the copper alloy according to the present invention, iron (Fe): 0.09 to 0.20%, phosphorus (P): 0.05 to 0.09%, and manganese (Mn): 0.05 to 0.20% by mass. %, The remaining amount of copper (Cu) and unavoidable impurities of 0.05% by mass or less, having a tensile strength of 470 MPa or more, a hardness of 145 Hv or more, an electric conductivity of 75% IACS or more, and an internal combustion temperature of 400%. ° C or higher.

Description

  The present invention relates to an electric / electronic component having high strength and high electrical conductivity, a copper alloy for a semiconductor, and a method for producing the same. Specifically, the present invention relates to a copper alloy containing copper (Cu), iron (Fe), phosphorus (P), and manganese (Mn), and a method for producing the same.

  A Cu-Fe-P-based alloy containing Fe and P is generally used as a copper alloy for various uses including materials for semiconductor lead frames and electric and electronic parts. For example, a copper alloy (C19210) containing Fe: 0.05 to 0.15% and P: 0.025 to 0.04% by mass%, Fe: 2.1 to 2.6%, P: 0.1% A copper alloy (C19400) containing 015 to 0.15% and Zn: 0.05 to 0.2% is widely used as a lead frame material because of its excellent strength and electrical conductivity among copper alloys. The reason why Fe and P are mainly used as additive elements is that they exhibit excellent strength and electrical conductivity by forming a precipitated phase in the copper matrix.

  However, among the various properties of copper alloys, strength and electrical conductivity have inversely proportional properties, which are opposite to each other.When strength increases, electrical conductivity decreases, and when electrical conductivity increases, strength decreases inevitably. is there. Therefore, the existing C19210 copper alloy has a tensile strength of 400 MPa and an electrical conductivity of 80% IACS, and has a low strength property but a good electrical conductivity property, so that it is used for products requiring high electrical conductivity. The existing C19400 copper alloy has a tensile strength of 500 MPa and an electrical conductivity of 60% IACS, and has low electrical conductivity characteristics but good strength characteristics, and is therefore used for products requiring high strength.

  In recent years, the characteristics of materials have become more important as electrical and electronic components become lighter and thinner. 2. Description of the Related Art Due to the trend of large capacity, miniaturization, and high integration of semiconductor devices used in electronic devices, vehicles, and the like, lead frames using semiconductors have been reduced in size and thickness. Therefore, the current copper alloy needs to satisfy higher strength, higher electric conductivity and excellent workability than the conventional copper alloy at the same time. It is required to simultaneously satisfy a tensile strength of 470 MPa or more and an electric conductivity of 75% IACS or more. Therefore, efforts to simultaneously improve strength and electric conductivity, which are mutually contradictory properties, are being made to satisfy the requirements of industrial systems.

  In order to increase the strength of the copper alloy, the content of Fe and P may be increased, or a third element such as Sn, Mg, or Ni may be added. However, when the amount of these elements is increased, the strength increases. However, the electric conductivity decreases. Accordingly, efforts have been made to improve the characteristics by reducing the size of crystal grains or controlling the size and distribution of crystal precipitates instead of the added elements. However, in this case as well, various problems such as generation of surface defects, reduction in reliability, and non-uniform microstructure occurred. Therefore, it is not easy to simultaneously improve the strength and electric conductivity of a copper alloy, and this is an important research subject.

In addition, in a field where a copper alloy material is applied, a step of applying heat is included. Therefore, a copper alloy needs to have a heat-resistant property. This property is called internal combustion property and can be evaluated based on the internal combustion temperature. The internal combustion temperature refers to a heat treatment temperature that indicates 80% of an initial (before heat treatment) hardness value when a hardness value that changes after heat treatment of the manufactured copper alloy sheet material for 1 minute is measured. The internal combustion temperature is used as an index indicating the property of the material to withstand heat, and is linked to the reliability of the final finished product as described above. With existing semiconductor packages or electronic components having an internal combustion temperature characteristic of 380 ° C. level, there was no problem in the production of products and the reliability of end products. However, copper alloys applied to recent semiconductor packages, electronic components, etc. are more favorable at the time of product processing, such as adding a process of applying heat such as soldering or wire bonding at the time of product processing. Since internal combustion properties are required, it is necessary to improve internal combustion properties at an internal combustion temperature of 400 ° C. or higher.

  At present, various patents have been filed for obtaining the strength and electrical conductivity required for copper alloy materials for lead frames.

  Korean Patent Application Publication No. 10-2008-0019274 (Patent Document 1) discloses that Mg is added to a Cu-Fe-P-based alloy to improve the strength. However, when Mg is added, the electric conductivity is inevitably reduced. When Mg is added to an existing Cu-Fe-P alloy system, the tensile strength is up to 450 MPa and the electrical conductivity is 70% IACS level, and the required characteristics of recent lead frames (tensile strength of 470 MPa or more, electrical conductivity of 75%). % IACS). The reason for this is explained by Mg-P-based coarse crystals. When Mg is added, the strength and electrical conductivity characteristics are inevitably reduced due to the generation of Mg-P-based coarse crystals and defects which are inevitably generated from the start of casting to the end of hot rolling.

Next, Korean Patent Application Publication No. 10-2005-0076767 (Patent Literature 2) describes that the grain size of a precipitate of a Cu—Fe—P alloy is controlled to improve the strength. However, since the present invention carries out two or more cold rolling and annealing steps in order to finely control the grain size of the precipitates, there are various variables, and it is difficult to actually manufacture them at an industrial site. It is. In this patent document, the volume fraction of precipitates is described as 1% or more and 300 particles / μm ² , but there is a problem that the volume fraction is a numerical value including coarse particles.

  Korean Patent Application Publication No. 10-2013-0136183 (Patent Document 3) describes that Mn is added to a Cu-Fe-P-based alloy to improve the strength. It does not reach the strength and electrical conductivity characteristics required in. Further, in claim 4 of the patent document, it is described that the precipitate particle size is controlled to a size of 10 to 30 μm. However, actually, the size of the precipitate is too large to be 10 to 30 μm. , Casting defects or foreign substances, and does not have the effect of improving strength and electrical conductivity. In this regard, when particles having a size of 10 to 30 μm are generally present in a copper alloy, a semiconductor package process cannot be performed due to a decrease in surface quality as well as a decrease in characteristics. In addition, there is no analysis result or basis that can specify what kind of precipitate is disclosed in this patent document, and only a simple crystal grain system that is not a precipitate is observed in the SEM analysis result of FIG. It is not a technical basis.

Korean Patent Application Publication No. 10-2008-0019274 Korean Published Patent Application No. 10-2005-0076767 Korean Published Patent Application No. 10-2013-0136183

  The present invention has been made to solve the above problems, and is an electric / electronic component having a level of strength and electric conductivity that satisfy the characteristics required in recent industrial systems, which is not satisfied by the conventional technology, and has excellent internal combustion properties. And a copper alloy for a semiconductor and a method for producing the same.

The copper alloy for an electric / electronic component or a semiconductor according to the present invention has an iron (Fe) content of 0.09 to 0.2 in mass%.
0%, phosphorus (P): 0.05 to 0.09%, manganese (Mn): 0.05 to 0.20%, and the remaining amount of copper (Cu) and 0.05% by mass or less. The inevitable impurities are any one selected from the group consisting of Si, Zn, Ca, Al, Ti, Be, Cr, Co, Ag, and Zr, and have a tensile strength of 470 MPa or more and a tensile strength of 145 Hv or more. , A conductivity of 75% IACS or more, and an internal combustion temperature of 400 ° C. or more. The content of inevitable impurities is preferably 0.01% or less. The copper alloy may further include any one of Ni and Sn in the range of 0.0001% to 0.03%.

  The copper alloy has an average crystal grain size of 20 μm or less and a standard deviation of 5 μm or less in a crystal grain size measured by a field orientation scanning electron microscope (FE-SEM) by a crystal orientation interpretation method.

The copper alloy contains (FeMn) ₂ P precipitates. This precipitate was obtained by subjecting a test piece manufactured by a carbon extraction replica (carbon extraction replica) method to 100,000 times magnification with a high-resolution transmission electron microscope (HR-TEM) or a field emission type transmission electron microscope (FE-TEM). When measured at the above magnification, the (FeMn) ₂ P precipitate has an average particle size of 50 nm or less and an areal density of 1.0 × 10 ¹⁰ / cm ² or more.

  The copper alloy can be in the form of a seed or plate.

  The method for producing a copper alloy for an electric / electronic component or a semiconductor according to the present invention includes a step of casting the ingot by dissolving the above-described component elements, and a homogenizing heat treatment of the obtained ingot at 900 ° C. to 1000 ° C. for 1 to 4 hours. Hot rolling at a working rate of 85 to 95%, cold rolling at a pressing rate of 87 to 98%, precipitation heat treatment at a temperature of 430 to 520 ° C for 1 to 10 hours, and 10 to 90. % Finish rolling at a press rate of%.

  The copper alloy according to the present invention has excellent strength and electric conductivity, and has excellent internal combustion characteristics. In addition, the copper alloy obtained has excellent strength and electrical conductivity despite the reduction of the manufacturing cost of the copper alloy due to the manufacturing process according to the present invention, and it can be used as a discrete transistor (discrete transistor or discrete TR) and a semiconductor lead frame. The present invention can be applied to various electric and electronic components other than the above.

13 is a graph showing the internal combustion characteristics of a copper alloy manufactured according to Example 5 and an existing copper alloy. 3 is an FE-SEM photograph showing a microstructure after hot rolling at 870 ° C. in a manufacturing process of a copper alloy having the composition described in Example 1. 4 is an FE-SEM photograph for confirming a microstructure after hot rolling at 900 ° C. in a manufacturing process of a copper alloy having a composition described in Example 1. 4 is an FE-SEM photograph for confirming a microstructure after hot rolling at 950 ° C. in a process of manufacturing a copper alloy having the composition described in Example 1. 9 is an FE-SEM photograph for confirming a microstructure of a copper alloy manufactured according to Example 5. 9 is an FE-TEM photograph of a test piece manufactured by an ion milling method to confirm a precipitate of a copper alloy having the composition described in Example 5. 9 is an FE-TEM photograph of a test piece manufactured by a carbon extraction replica method to confirm a precipitate of a copper alloy having the composition described in Example 5.

  The present invention provides an electric / electronic component, a copper alloy for a semiconductor, and a method for producing the same, which are excellent in strength and electric conductivity and have excellent internal combustion characteristics. In this specification,% indicating the content of a component element is% by mass unless otherwise specified.

<Copper alloy according to the present invention>
In the copper alloy according to the present invention, iron (Fe): 0.09 to 0.20%, phosphorus (P): 0.05 to 0.09%, and manganese (Mn): 0.05 to 0.20% by mass. %, The remaining amount of copper (Cu) and inevitable impurities of 0.05% by mass or less, and the inevitable impurities are selected from the group consisting of Si, Zn, Ca, Al, Ti, Be, CR, Co, Ag, and Zr. And a copper alloy for electric or electronic parts or semiconductors having a tensile strength of 470 MPa or more, a hardness of 145 Hv or more, an electric conductivity of 75% IACS or more, and an internal combustion degree of 400 ° C. or more.

  Hereinafter, the component composition of the copper alloy according to the present invention will be described. In this specification, the indicated% with respect to the content of the element is mass% unless otherwise specified.

[Fe]
Fe is an element necessary for forming fine (FeMn) ₂ P precipitates and improving strength and electrical conductivity. The content of Fe is in the range of 0.09 to 0.20%. If the content is less than 0.09%, the particles required for the formation of precipitates are insufficient, and the effect of suppressing the growth of crystal grains by the precipitates is reduced. As a result, the average crystal grain size and the standard deviation of the average crystal grain size increase, and the strength decreases. Therefore, in order to exert these effects effectively, the content of 0.09% or more is necessary. However, if the content exceeds 0.20%, the precipitate becomes coarse, the standard deviation of the average crystal grain size increases, the bending workability decreases, and the electrical conductivity also decreases.

[P]
In addition to the deoxidizing action, P combines with Fe and Mn to form (FeMn) ₂ P fine precipitates, thereby improving the strength and electric conductivity of the copper alloy. The content of P is 0.05 to 0.09%. When the content of P is less than 0.05%, formation of fine precipitates is insufficient, and the effect of suppressing the growth of crystal grains by the precipitates is reduced. As a result, the average crystal grain size and the standard deviation of the average crystal grain size increase, and the strength decreases. Therefore, the content must be 0.05% or more. However, if the content exceeds 0.09%, the number of coarse precipitate particles increases, so that the standard deviation of the average crystal grain size increases and the bending workability decreases. In addition, the electric conductivity also decreases.

[Mn]
It has been reported that Mn usually contributes to strength improvement when a copper alloy is added. However, when Mn is simply added to increase strength, the electrical conductivity of a finally obtained copper alloy necessarily decreases. In the copper alloy according to the present invention, by forming (FeMn) ₂ P precipitates, it is possible to improve not only strength but also electric conductivity. In the copper alloy of the present invention, the content of Mn is 0.05 to 0.20%. When the content of Mn is as small as less than 0.05%, the formation of precipitates is insufficient, the effect of suppressing the growth of crystal grains is reduced, and the strength is reduced similarly to Fe described above. However, if it exceeds 0.20%, both the strength and the electrical conductivity are reduced due to coarse crystals and casting defects.

[Inevitable impurities]
Further, the copper alloy of the present invention contains any one selected from the group consisting of Si, Zn, Ca, Al, Ti, Be, CR, Co, Ag and Zr in a range of 0.05% or less. . Preferably, the addition amount is 0.01% or less. These elements are elements that play a role in improving various properties of the copper alloy, and are preferably added selectively depending on the application.

In addition, in the copper alloy according to the present invention, in the case of magnesium (Mg), which is generally widely known to have an excellent strengthening effect, the strength of the copper alloy finally obtained when added is slightly improved, but the electric conductivity is improved. A drop is inevitable and magnesium reacts with the phosphorus and inevitably causes Mg-P-based coarse crystals and defects from the start of casting to the end of hot rolling, and must be excluded.

[Ni] and [Sn]
Further, it may contain 0.0001% to 0.03% of any one of Ni and Sn. Ni is a solid solution in the Cu matrix, has the effect of improving the strength, and is an element effective for heat resistance. If it is less than 0.0001%, the effect of improving the strength cannot be achieved, and if it exceeds 0.03%, the electric conductivity will be reduced.

  Sn is a solid solution strengthened alloy element having the effect of improving strength by being solid-dissolved in the Cu matrix. If it is less than 0.0001%, the effect of improving strength is not expected, and if it exceeds 0.03%. This leads to a decrease in electric conductivity.

<Characteristics of the copper alloy according to the present invention>
Generally, it is very difficult to control the two properties of copper alloys because electrical conductivity tends to decrease as strength increases.

  The strength of the copper alloy according to the present invention can satisfy both the tensile strength of 470 MPa or more and the hardness of 145 Hv or more. This is a numerical value that reflects the characteristics required of industrial systems recently, and can be said to be a limit value characteristic in consideration of the strength and electric conductivity characteristics of a copper alloy exhibiting an inverse proportional characteristic.

  Further, the electrical conductivity of a copper alloy used for a semiconductor or an electric / electronic component needs to be 75% IACS or more. If the following electrical conductivity characteristics are exhibited, the transmission of electrical signals is not smooth and cannot be used for products. The electrical conductivity of the copper alloy according to the invention is above 75% IACS.

  That is, the copper alloy according to the present invention exhibits excellent properties in which the properties of strength and electric conductivity are simultaneously improved.

  Also, the copper alloy according to the present invention has an excellent internalization temperature of 400 ° C. or more. The internal combustion temperature will be described later in the method for producing a copper alloy according to the present invention.

<Method for producing copper alloy according to the present invention>
The copper alloy according to the present invention is manufactured by a manufacturing method described below. First, an ingot is cast by dissolving the component elements having the above-described composition. Immediately after the obtained ingot is subjected to homogenizing heat treatment at 900 to 1000 ° C. for 1 to 4 hours, hot rolling is performed at a working ratio of 85 to 95%. At the same time as the completion of the hot rolling, the solute element is solid-dissolved by water cooling to form a solution treatment, and cold rolling is performed at a working ratio of 87 to 98%. After accumulating high deformation energy by cold rolling to increase the driving force for precipitate formation, a precipitation heat treatment is performed at 430 to 520 ° C. for 1 to 10 hours. Thereafter, finish rolling is performed at a pressing rate of 10 to 90% to determine the final thickness of the product.

  Specifically, each step of the above-described method for producing a copper alloy according to the present invention will be described.

  First, an ingot is manufactured by melting and casting the above-mentioned component elements.

Next, immediately after the obtained ingot is subjected to homogenizing heat treatment at 900 to 1000 ° C. for 1 to 4 hours, hot rolling is performed at a working ratio of 85 to 95%. Homogenization heat treatment is an essential step for hot rolling, in which the ingot is not cold worked, but is hot rolled in a sufficiently heated state to remove the cast structure and form a new recrystallized structure. It is a process. The hot rolling step is the most important step in the method for producing a copper alloy according to the present invention. The hot rolling condition is a factor which has an important effect on the metallographic structure among the alloy characteristics, and the structure after hot rolling differs depending on the hot rolling condition, thereby changing the characteristics of the finished product. The hot rolling conditions are large and include a hot rolling temperature, the number of hot rolling passes, and cooling conditions. The structure obtained after hot rolling differs depending on each condition.

  In order to achieve the properties of the copper alloy according to the present invention, the hot rolling temperature must be in the range of 900-1000 ° C. When the temperature is in the hot rolling temperature range, an isotropic recrystallized structure having no directivity can be obtained. As can be confirmed from the examples described later, when the hot rolling temperature is lower than 900 ° C., a processed structure (rolled structure) remains. In the case of an existing general copper alloy for a lead frame, a solution treatment and a precipitation step are added one or more times in order to prevent deterioration of the properties of the final finished product. This leads to a decrease. On the other hand, in the case of the copper alloy according to the present invention, characteristics can be exhibited without such an additional process, so that process costs can be reduced and productivity can be improved.

  When heating for a homogenizing heat treatment in a temperature range of 900 ° C. to 1000 ° C. for 1 to 4 hours, an isotropic recrystallized structure is obtained and at the same time the effect of solution treatment is exerted. If the heating is performed for less than one hour, the processed structure remains locally and the characteristics of the isotropic recrystallized structure cannot be completely exhibited. Further, when heating is performed for more than 4 hours, there is a problem that the ingot is partially melted. The solution treatment is a step of maximizing the effect of precipitation by supersaturating an element having a solubility equal to or higher than Cu in the Cu matrix, and a general precipitation hardening alloy involves a further solution treatment with a thin plate thickness. As a result, process costs increase and productivity decreases. However, since the copper alloy according to the present invention obtains the effect of solution treatment by heat treatment in the hot rolling process, high deformation energy is accumulated in the material by 87-98% strong rolling in the cold rolling process thereafter. can do. The high deformation energy remaining inside the material becomes a driving force of the precipitation process after cold rolling, and enables fine precipitates to be evenly distributed in the precipitation process.

  Next, at the same time as the completion of the hot rolling, water cooling is carried out to solid-dissolve solute elements and to perform a solution treatment, and cold rolling is performed at a working ratio of 87 to 98%. Cold rolling can accumulate high deformation energy and increase the driving force for precipitate formation.

Next, precipitation heat treatment is performed at 430 to 520 ° C. for 1 to 10 hours. The copper alloy according to the present invention is a precipitation hardening type alloy, and the precipitation step is very important. Although the copper alloy according to the present invention is a new copper alloy to which Mn is added, simply adding Mn does not involve the optimal strength and electric conductivity, so that fine precipitates are evenly distributed by the precipitation step. This embodies dispersing formation. In the case of an existing Cu-Fe-P-based alloy, Fe ₂ P precipitates are mainly present in the copper alloy, and coarse FeP precipitates are locally present to deteriorate properties. On the other hand, in the method for producing a copper alloy according to the present invention, fine (FeMn) ₂ P precipitates are dispersed and formed in the copper alloy by performing the precipitation heat treatment under the above conditions, and all of the high strength and high electric conductivity characteristics are obtained. Can be achieved.

  Finally, finish rolling is performed at a pressing rate of 10 to 90%. Finish rolling is performed by cold rolling at a working ratio of 10 to 90% to secure target physical properties. At this time, a preferable range of the working ratio is 30 to 70%, and in this range, the efficiency of the strength increase with respect to the working amount of the invention alloy is highest.

Further, in the above method, if necessary, after the precipitation heat treatment and before the final finish rolling, the intermediate heat treatment can be performed after cold rolling at a working ratio of 30 to 90%. The cold rolling and intermediate heat treatment steps at a working rate of 30 to 90% include baking (partial joining by heat and pressure) and pickling after the precipitation heat treatment, which can occur depending on the process and production conditions of the mass production line precipitation heat treatment equipment. ) Is for solving the problem of surface quality such as scratch, and is not an essential step. Intermediate heat treatment can be applied when there is a large difference between the product thickness after precipitation heat treatment and the thickness after finish rolling and it is out of the range of target physical properties (strength, electrical conductivity) or it is difficult to secure the target characteristics . At this time, the intermediate heat treatment aims at reducing the strength, and the decrease in electric conductivity must be minimized. Therefore, it is important to perform the heat treatment so that the electric conductivity decreases within the range of 0.1 to 3% IACS. . When the electric conductivity decreases below 0.1% IACS, the effect of the heat treatment is not obtained. When the electric conductivity decreases beyond 3% IACS, the effect of the heat treatment is large, but the electric conductivity and the strength are not increased. May deviate from the target properties of the developed alloy due to the decrease in

In the production process of the copper alloy according to the present invention, the hot rolling and the precipitation heat treatment process have an important effect on the properties of the finally obtained copper alloy, and the distribution of fine (FeMn) ₂ P precipitates in the copper alloy according to the present invention. For this purpose, precise control of the production process is required in the order from the hot rolling to the precipitation process. In order to confirm fine precipitates generated in the copper alloy, FE-SEM and FE-TEM observation are essential.

The copper alloy produced by the method for producing a copper alloy according to the present invention contains fine (FeMn) ₂ P precipitates and has a fine structure at a magnification of 100,000 times or more by a crystal orientation interpretation method using FE-TEM. When observed, the average particle size of the (FeMn) ₂ P precipitate is 50 nm or less, and the areal density is 1.0 × 10 ¹⁰ particles / cm ² or more.

  Conventionally, a TEM test piece of a general ion milling method has been manufactured for observation of the precipitate, but it is impossible to observe a fine precipitate having a size of several to several tens of nm with this test piece. Even if an attempt is made to observe fine precipitate particles, it is difficult to distinguish impurities or foreign substances from precipitates with a TEM specimen manufactured by an ion milling method, and the crystal structure and composition of the precipitates cannot be confirmed. . On the other hand, a test piece manufactured by the carbon extraction replica method can be analyzed by TEM to observe fine precipitates of the copper alloy according to the present invention.

In the copper alloy according to the present invention, fine (FeMn) ₂ P precipitates are uniformly distributed in the grain boundaries and in the grains, and the average particle size of the (FeMn) ₂ P precipitates is 50 nm or less. If the average particle size of the precipitate exceeds 50 nm, a decrease in electric conductivity is inevitable, and a problem of insufficient reliability in a semiconductor process can be caused. The average particle size of the precipitate can be measured, for example, by observing the crystal orientation by a field emission type transmission electron microscope (FE-TEM) at a magnification of 100,000 or more. In this connection, FIGS. 4a and 4b show the results of FE-TEM analysis of the copper alloy according to the present invention in the examples described later.

Further, the areal density can be measured based on the FE-TEM results as shown in FIGS. 4A and 4B. The areal density is the number of precipitates present in a certain area range, and is a measure for measuring the dispersion of the precipitates. In the past, the volume fraction was used to measure the dispersion of precipitates, but the volume fraction indicates the ratio of precipitates within a certain range, so when very large coarse particles were generated Has a considerably large error range. On the other hand, when the concept of areal density is used, the presence of the coarse particles does not affect the numerical value of the areal density, and the degree of dispersion of the precipitate can be confirmed more accurately. The areal density of the copper alloy according to the present invention is 1.0 × 10 ¹⁰ pieces / cm ² or more. Since the average particle size of the (FeMn) ₂ P precipitate of the copper alloy according to the present invention is 50 nm or less and is very fine, a large amount of precipitate formation is necessary to exhibit the characteristics of the inventive alloy, When the number of precipitates, that is, the area density is 1.0 × 10 ¹⁰ / cm ² or less, sufficient strength cannot be exhibited.

The internalization temperature of the copper alloy according to the present invention is 400 ° C. or higher. The internal combustion temperature must be at least 400 ° C. or higher in order to exhibit sufficient internal combustion characteristics in electrical and electronic component and semiconductor applications. In the present invention, since the precipitation strengthening is carried out instead of the grain refinement method as a means for improving the strength of the copper alloy, the internal combustion characteristics are excellent. If strong strain processing is performed to refine crystal grains, poor softening can occur due to high internal stress. Poor softening means that the hardness of the raw material is softened by heat during processing of the raw material and semiconductor packaging, resulting in defective products.

  The electric / electronic component or the copper alloy for semiconductor according to the present invention can be manufactured in the form of a sheet or a plate. The form of the sheet or plate is suitable for application to semiconductor or IC lead frames or connectors and terminals.

  As described above, the copper alloy according to the present invention has excellent strength and electrical conductivity at the same time as existing products by blending the composition of the copper alloy and precisely controlling the manufacturing process, and has excellent internal combustion characteristics. It is particularly applicable not only to electric and electronic components such as semiconductor lead frames, terminals, connectors, switches, relays and the like which have been widely used in the past, but also to discrete transistors which are semiconductors for automotive power control, which have been increasing in demand recently.

<Examples 1 to 16>
Test pieces of Examples 1 to 16 are manufactured according to the compositions shown in Table 1. The method for producing the test piece will be described later.

  An alloy element containing copper based on the composition shown in Table 1 and containing 1 kg each was melted in a high-frequency melting furnace, and an ingot having a thickness of 20 mm, a width of 50 mm, and a length of 160 to 180 mm was cast. In order to remove defective portions such as rapid cooling and shrinkage holes, the manufactured ingot was cut at a lower end and an upper end by 20 mm each, and then was subjected to a 900 ° C. box furnace using an ingot in the middle part. A time-homogenizing heat treatment was performed to advance hot rolling at a working ratio of 90%. At the same time as the completion of the hot rolling, water-cooling and solution treatment were performed to prevent precipitation of solute elements. Before the precipitation process, a high deformation energy is accumulated by cold rolling at a working ratio of 90% to increase the driving force for forming precipitates, and then a precipitation heat treatment is performed at 450 ° C. for 3 hours, and a cold working at a working ratio of 50% is performed. Finished by rolling. Finally, the finish-rolled copper alloy was manufactured into a test piece having a size of 0.3 t × 30 w × 200 L and used for the next test. Table 2 shows the characteristic analysis results disclosed in the test examples of the test pieces of the copper alloys manufactured according to Examples 1 to 16.

<Comparative Example 1 to Comparative Example 16>
The test pieces of Comparative Examples 1 to 16 were manufactured with the compositions shown in Table 1 in the same manufacturing process as in Examples 1 to 16. Table 2 also shows the results of the characteristic analysis of the copper alloy test pieces manufactured according to Comparative Examples 1 to 16.

  Examples 1 to 14 are examples for evaluating the critical significance of the composition ranges of Cu, Fe, Mn, and P, and are shown in Table 1. Examples 14 to 16 are examples for confirming the effects of Ni and Sn added elements. The component of Comparative Example 1 has the same composition as the C19210 alloy widely used for lead frames. In Comparative Examples 8 to 13, Mn was added to an existing C19210 alloy.

<Test example>
Hereinafter, a method of analyzing characteristics of a test piece of a copper alloy manufactured according to an example and a comparative example will be described.

  Tensile strength is measured using a ZWICK ROELL Z100 competence tester, hardness is measured using an INSTRON TUKON 2500 Vickers hardness tester under a 1 kg load, and electrical conductivity is measured using a FOERSTER SIGMATEST. did.

  During the analysis of the internalization temperature, the heat treatment was performed using a THERMO SCIENTIFIC Thermolyne 5.8L D1 bench-top muffle furnace (Benchtop Muffle Furnace). Specifically, the internal combustion temperature was calculated by subjecting a test piece to a heat treatment at a temperature of 300/350/400/450/500/550/600/650/700 ° C. for 1 hour, and then measuring the hardness value. After plotting a line graph of hardness (Y-axis) -temperature (X-axis), a temperature value crossing the 80% point of the initial hardness value was derived and shown. The results are shown in FIG. 1 as an example of the invention alloy of Example 5 in comparison with existing C19400 and C19210 alloys.

The average crystal grain size of the fine structure of the test piece was measured using Quanta650 FEG (FE-SEM) manufactured by FEI. After electropolishing the surface of the test piece for measuring the average crystal grain size, the test piece was placed in an FE-SEM chamber, and the degree of vacuum in the chamber was maintained at 1 × 10 ⁻⁵ torr or less. Irradiation and observation by crystal orientation interpretation method. FIG. 3 shows the observation results of the microstructure of the inventive alloy of Example 5.

  JEM-2100F (FE-TEM) manufactured by JEOL was used for measuring the average particle diameter and the areal density of the precipitate. Analysis was performed in two ways for FE-TEM observation. First, a result of FE-TEM analysis using an ion milling method, which is a general test piece manufacturing method, is shown in FIG. 4A. As can be seen from FIG. 4a, confirmation and analysis of the fine precipitate was not possible. Therefore, in order to analyze fine precipitates that cannot be confirmed by the ion milling method, the result of analyzing the test piece manufactured by the carbon extraction replica method by FE-TEM is shown in FIG. 4B.

  The results measured by the above-described characteristic analysis method are shown in Table 2 below.

In Table 2, when Example 4 and Comparative Example 8 are compared, Example 4 is obtained by increasing the P content to the components of Comparative Example 8, and is sufficient for forming fine (FeMn) ₂ P precipitates. By providing the amount of P, it can be confirmed that the strength is improved and the electric conductivity is improved. Also, when the results of Example 5 are confirmed, it can be confirmed that both the strength characteristics and the electric conductivity characteristics are simultaneously satisfactorily realized.

Note that Comparative Examples 1 to 16 do not satisfy the strength criterion, which is one of the required characteristics of industrial systems at present, even if the precipitate control is performed by optimizing the manufacturing process. This is because it is impossible to form fine (FeMn) ₂ P precipitates outside the optimum composition of the alloy of the present invention.

Among the comparative examples, Comparative Examples 8 to 13 are experiments for confirming whether simply adding Mn to an existing C19210 alloy is effective. The results of Comparative Examples 8 to 13 confirm that simply adding Mn does not satisfy the required characteristics. This means that the addition of simple Mn alone does not result in the formation of (FeMn) ₂ P precipitates, but instead results in the Mn being dissolved in the Cu matrix to reduce the electrical conductivity, which eventually results in (FeMn) ₂ This is due to the lack of P content required for the formation of P precipitates. In particular, it can be confirmed that the strength is somewhat improved only by the solid solution strengthening of the simple addition element, but the electrical conductivity tends to decrease rapidly.

  Summarizing the results of the characteristic analysis described above, it can be seen that the composition of the existing C19210 shows improved alloy characteristics even when the same manufacturing method and analysis method as those in Examples 1 to 16 showing the characteristics of the alloy of the present invention are combined. It can be confirmed that it cannot be done.

  In order to evaluate the properties under the temperature conditions of the hot rolling, test pieces of the copper alloy having the composition of Example 1 were manufactured while changing the temperature conditions of the hot rolling as shown in Table 3 below. Then, their physical properties were evaluated.

  As can be seen from Table 3, when the hot rolling temperature is lower than 900 ° C., the properties of the copper alloy according to the present invention cannot be exhibited. The results in Table 3 are shown in FIGS. 2a to 2c. FIG. 2A shows a hot-rolled copper alloy for a lead frame at 870 ° C., which is a general hot-rolling condition. Observation of the structure after hot rolling reveals that the processed structure (rolled structure) remains It can be confirmed that the influence is exerted on the process, whereby the property of the final finished product is deteriorated. 2B and 2C, since the hot rolling temperature is 900 ° C. or higher, an isotropic recrystallization structure is formed after hot rolling, thereby realizing the characteristics of the alloy of the present invention.

  In addition, in order to confirm the average crystal grain size and the microstructure of the copper alloy according to the present invention, a photograph of a test piece of the copper alloy manufactured in Example 5 observed by FE-SEM is shown in FIG. According to the photograph of FIG. 3, the average crystal grain size in the test piece according to Example 5 is 20 μm or less, and the standard deviation is 5 μm or less. These results confirm that when the copper alloy according to the present invention is used for electrical and electronic components and semiconductors, it has a fine level of microstructure that can be used without the problem of surface defects.

  FIGS. 4A and 4B show the results of analyzing the copper alloy test piece of Example 5 by FE-TEM.

  FIG. 4a is an FE-TEM photograph of a test piece manufactured by an ion milling method generally used for confirming a precipitate in a copper alloy having the composition described in Example 5, and the presence of the precipitate and Since the observation of the presence or absence of dispersion is unknown, accurate analysis cannot be performed. To solve such problems, new analytical methods need to be applied.

FIG. 4b is an FE-TEM photograph of a test piece manufactured by a carbon extraction replica method to confirm a precipitate in a copper alloy having the composition described in Example 5 in order to overcome the limitations of the existing ion milling method. is there. When observing a test piece manufactured by the carbon extraction replica method, it is possible to accurately analyze the shape, size, composition, area density, and the like of the fine precipitate. In FIG. 4a, only the existence degree of the precipitate can be confirmed, but from FIG. 4b, the (FeMn) ₂ P-based precipitate which is not seen in the existing Cu—Fe—P-based alloy is uniformly formed, It can be confirmed that the average particle size is 50 nm or less, and the areal density of the precipitate is 1.0 × 10 ¹⁰ (pieces / cm ² ) or more.

Claims (6)

In mass%, iron (Fe): 0.09 to 0.20%, phosphorus (P): 0.05 to 0.09%, manganese (Mn): 0.05 to 0.20%, the remaining amount of copper ( Cu) and 0.05% by mass or less of inevitable impurities, wherein the inevitable impurities are any one selected from the group consisting of Si, Zn, Ca, Al, Ti, Be, Cr, Co, Ag, and Zr. And
(FeMn) ₂ P precipitates, and the (FeMn) ₂ P precipitates were prepared by subjecting a test piece manufactured by a carbon extraction replica method to a high-resolution transmission electron microscope (HR-TEM) or a field emission type. Was measured at a magnification of 100,000 times or more with a transmission electron microscope (FE-TEM), and the (FeMn) ₂ P precipitate had an average particle size of 50 nm or less and an areal density of 1.0 × 10 ¹⁰ particles / cm ² or more,
A copper alloy for electric / electronic parts or semiconductors having a tensile strength of 470 MPa or more, a hardness of 145 Hv or more, an electrical conductivity of 75% IACS or more, and an internal combustion temperature of 400 ° C. or more.   2. The copper alloy for electric / electronic parts or semiconductors according to claim 1, wherein the content of the inevitable impurities is 0.01% by mass or less. 3.   The electric / electronic component or the copper alloy for a semiconductor according to claim 1, further comprising one of Ni and Sn in a range of 0.0001% by mass to 0.03% by mass.   The copper alloy has an average crystal grain size of 20 μm or less and a standard deviation of 5 μm or less in a crystal grain size measured by a field orientation scanning electron microscope (FE-SEM) by a crystal orientation interpretation method. 2. The copper alloy for an electric / electronic component or a semiconductor according to 1.   The copper alloy for an electric / electronic component or a semiconductor according to claim 1, wherein the copper alloy is in a form of a sheet or a plate material. Dissolving the component elements according to any one of claims 1 to 3 to cast an ingot;
A step of subjecting the obtained ingot to a homogenizing heat treatment at 900 ° C. or higher and 1000 ° C. or lower for 1 to 4 hours and hot rolling at a working ratio of 85 to 95%;
Cold rolling at a pressing ratio of 87 to 98%,
A method for producing a copper alloy for electric / electronic parts or a semiconductor, comprising a step of performing a precipitation heat treatment at a temperature of 430 to 520 ° C. for 1 to 10 hours, and a step of finish rolling at a depression rate of 10 to 90%.

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