JP6887399B2 - Manufacturing method of copper alloy material, electronic parts, electronic equipment and copper alloy material - Google Patents

Description

The present invention relates to a copper alloy material, an electronic component, an electronic device, and a method for manufacturing a copper alloy material. More specifically, the present invention relates to a copper alloy material, an electronic component, an electronic device, and a method for manufacturing a copper alloy material in which fluctuation in thickness is suppressed.

Copper alloys for electronic materials used in various electronic components such as connectors, switches, relays, pins, terminals, and lead frames are required to have both high strength and high conductivity (or thermal conductivity) as basic characteristics. Will be done. In recent years, the level of integration, miniaturization, and thinning of electronic components has rapidly progressed, and in response to this, the required level for copper alloys used in electronic device components has become more sophisticated.

More specifically, copper alloys are press-processed for electronic parts, and this press-processed product is also required to be miniaturized. In addition, thinning of copper alloy strips, which are materials for pressed products, is also required. Patent Document 1 discloses that the drooping curl is sufficiently suppressed for the copper alloy strip. When drooping curl occurs, when the terminals for electronic materials are pressed, there arises a problem that the shape after the press working is not stable, that is, the dimensional accuracy is lowered. Therefore, it is desired to suppress it as much as possible.
Also, as with the hanging curl, if the thickness of the foil or strip does not match the pre-designed one, when pressing the terminal for electronic material, the shape after press working will not be as designed. That is, since there is a problem that the dimensional accuracy is lowered, it is desired to control as much as possible.

Japanese Unexamined Patent Publication No. 2012-21355

No matter how thin the copper alloy material is, if it is not flat, it will not be possible to sufficiently reduce the size of the pressed product. The reason for this is that in a stamped product of a material having a warped shape in the length direction, the curvature due to the warped shape is added to the dimensions, which hinders miniaturization. Also, as with the hanging curl, if the thickness of the foil or strip does not match the pre-designed one, when pressing the terminal for electronic material, the shape after press working will not be as designed. That is, the dimensional accuracy is lowered. Poor dimensional accuracy requires significant dimensional tolerances in shape design, which hinders miniaturization.

Therefore, the copper alloy material is straightened into a flat shape at the time of manufacturing the copper alloy material or before pressing. Further, suppressing the amount of curl as disclosed in Patent Document 1 is also one means. Further, regarding the thickness of the foil or strip, there is an automatic sheet thickness control system in the rolling mill, and the thickness can be controlled to the median value of the standard defined in the design of the stamped product. However, there is still room for improvement in order to keep the shape of the stamped product constant even if it is straightened to a flat shape, curl is suppressed, and even if the thickness is controlled to the median value of the standard. there were. In particular, among the copper alloy materials, such a tendency was observed in the strips of Corson alloy. Therefore, an object of the present invention is to provide a copper alloy material in which the shape of a pressed product can be easily made constant.

As a result of investigation by the present inventors, it is important that the thickness of the copper alloy does not necessarily have to be at the median value of the standard defined in the design of the stamped product, and that the thickness does not fluctuate in the length direction. found. That is, even if the material has a thickness at the median of the standard (eg, strip, plate, foil, etc.), the shape of the pressed product is not constant if the thickness fluctuates in the length direction. In addition, even if the material has a thickness that deviates from the median of the standard (eg, strips, plates, foils, etc.), and even if the thickness deviates from the median but also slightly deviates from the standard, the thickness in the length direction increases. If it does not fluctuate, the shape of the pressed product will be constant by adjusting the straightening conditions according to the thickness. Based on the above findings, the present invention is specified as follows.

(Invention 1)
A total of 0.5 to 5.0% by mass of one or more of Ni and Co,
Contains 0.1 to 1.2% by mass of Si
The balance is a copper alloy material consisting of copper and unavoidable impurities.
The copper alloy material is a strip, plate or foil.
A copper alloy material having a thickness variation of 0.0 μm to 2.0 μm at five measurement points located side by side at intervals of 60 mm in a direction parallel to the rolling direction.
(Invention 2)
The copper alloy material of Invention 1 further containing one or more of Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B in a total amount of 0.005 to 3.0% by mass.
(Invention 3)
An electronic component comprising the copper alloy material according to Invention 1 or 2.
(Invention 4)
An electronic device including the electronic component of the invention 3.
(Invention 5)
The method for producing a copper alloy material according to Invention 1 or 2, wherein the method is:
Melting casting process and
Hot rolling process and
The first cold rolling process and
The first solution treatment process and
Second cold rolling process and
Second solution treatment process and
Third cold rolling process and
Third solution treatment process and
Aging process and
The final cold rolling process and
Including
The workability in the second cold rolling step is 70% or more, and the degree of processing is 70% or more.
The workability in the third cold rolling step is 50% or more and 70% or less.
The first solution treatment step includes adjusting the crystal grain size to 0.090 mm or more, and the second solution treatment step includes adjusting the crystal grain size to 0.020 mm to 0.040 mm.
The method.

In the present invention, on one side surface, the variation in thickness in the direction parallel to the longitudinal direction is 0.0 μm to 2.0 μm. As a result, a constant shape can be obtained when press working.

Hereinafter, specific embodiments for carrying out the present invention will be described. The following description is for facilitating the understanding of the present invention. That is, it is not intended to limit the scope of the present invention.

1. 1. Copper Alloy Materials In one embodiment, the present invention includes copper alloy materials. The shape of the material is strip, plate, or foil.
"Stripe" (ribbon) refers to "a rolled product having a uniform wall thickness of 0.1 mm or more, having a rectangular cross section, and being supplied in a slit coil shape".
"Sheet, plate" refers to "a rolled product having a uniform wall thickness of 0.1 mm or more, having a rectangular cross section, and being supplied by a sheared or sawed flat plate".
"Foil" refers to "a rolled product having a uniform wall thickness of less than 0.1 mm, having a rectangular cross section, and being supplied in a slit coil shape".

1-1. Composition The composition of the copper alloy contains 0.5 to 5.0% by mass of one or more of Ni and Co in total and 0.1 to 1.2% by mass of Si, and the balance is copper and unavoidable impurities. Consists of.

1-1-1. Ni and Co
The Ni and Co are subjected to an appropriate heat treatment to form an intermetallic compound, and the strength can be increased without deteriorating the conductivity. One or more of Ni and Co can be added in a total amount of 0.5 to 5.0% by mass. If it is less than 0.5% by mass, the desired strength cannot be obtained, and conversely, if it exceeds 5.0% by mass, the strength can be increased, but the conductivity is remarkably lowered and the bending workability is also lowered. More preferably, one or more of Ni and Co can be added in a total amount of 1.0 to 3.0% by mass.

1-1-2. Si
Similar to Ni and Co, the Si forms an intermetallic compound by subjecting it to an appropriate heat treatment, so that the strength can be increased without deteriorating the conductivity. Si can be added in an amount of 0.1 to 1.2% by mass. If it is less than 0.1% by mass, the desired strength cannot be obtained, and conversely, if it exceeds 1.2% by mass, the strength can be increased, but the conductivity is remarkably lowered and the bending workability is also lowered. More preferably, 0.2 to 0.7% by mass can be added.

1-1-3. Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, B
As elements other than the above, one or more of Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B may be further added in a total amount of 0.005 to 3.0% by mass. It may or may not be added (for example, it may be 0% by mass). By adding these elements, among the mechanical properties such as hot workability in manufacturing, proof stress, tensile strength, spring limit value and stress relaxation property in products, and surface properties such as soldering properties and plating properties in products. The effect that any one or more becomes good can be obtained. If it is added too much, the conductivity will decrease, so more preferably 0.005 to 1.0% by mass can be added.

1-1-4. Remaining part In one embodiment, the remaining part other than the above may be Cu. Here, unavoidable impurities may be contained in addition to the Cu. Examples of unavoidable impurities include S and O. The content of unavoidable impurities is not particularly limited, but is, for example, 100 mass ppm or less in total.

1-2. Dimensions In one embodiment, the width of the copper alloy material of the present invention is not particularly limited, but may be 10 to 50 mm. If it is less than 10 mm, the number obtained by pressing a unit stroke is small, and the productivity is lowered. If it exceeds 50 mm, the dimensional accuracy of the pressed product will decrease.

In one embodiment, the thickness of the copper alloy material of the present invention is not particularly limited, but may be 0.15 mm or less. The reason for this is that defects in press working due to fluctuations in thickness become apparent at 0.15 mm or less. More preferably, it is 0.1 mm or less. The lower limit is not particularly limited, but may be typically 0.05 mm or more.

1-3. Thickness In one embodiment, the copper alloy material of the present invention has a thickness variation of a specific value or less. Here, first, the thickness will be described.

Generally, the thickness of copper and copper alloy plates, strips and foils is measured by a micrometer in units of 1 μm. In the present invention, a micrometer having specifications having an accuracy of 0.1 μm unit is used (for example, Nikon Corporation, DIGIMICRO, Nikon MH-15M).
Then, as will be described later, the thickness was measured at five points, and the average value was used as a representative value of the thickness of the copper alloy material.

1-4. Thickness variation In the present specification, the “thickness variation” is a value obtained by measuring and calculating by the following procedure.
(1) The thickness is measured at five measurement points aligned in a straight line in the direction parallel to the rolling direction, separated from each other at intervals of 60 mm, and the difference between the maximum value and the minimum value of the five thickness data obtained thereby. Define.
(2) The thickness at these five measurement points is measured at least once for each coil of the plate, strip or foil, and the thickness variation at the five measurement points is 0.0 μm to 2 at least once. If it is within the range of 0.0 μm, it is included in the present invention.
The above five measurement points were measured at the center position in the width direction of the plate, strip or foil, which was slit in the width of the product.

In one embodiment, the thickness variation of the copper alloy material of the present invention may be 2.0 μm or less. For a material having a thickness variation of more than 2.0 μm, it becomes difficult for the shape of the pressed product to be constant in the press working of the copper alloy material. It is more preferably 1.5 μm or less, and further preferably 1.0 μm or less. The lower limit is not particularly limited, but is typically 0.0 μm or more.

2. Manufacturing Method In one embodiment, the present invention includes a method for manufacturing a copper alloy material. The manufacturing method can include the following steps.
(Melting casting process) → (Hot rolling process) → (First cold rolling process) → (First solution processing process) → (Second cold rolling process) → (Second solution processing process) → ( Third cold rolling process) → (third solution treatment process) → (aging treatment process) → (final cold rolling process).

Another step may be inserted before and / or after each of the above steps. For example, a strain removing annealing step may be introduced after the final cold rolling step. Further, after the above-mentioned process is completed, the width may be processed to an appropriate size (for example, 600 to 650 mm), and then a slitter may be used to process the width to a predetermined width. Then, it can be wound into a coil and shipped as a product.

2-1. Melt casting In the melt casting step, melt casting can be performed using an ingot having the same composition as the copper alloy material of the present invention described above. The thickness of the ingot is preferably 1500 times or more the thickness of the copper alloy material. When it is 1500 times or more, it becomes easy to suppress that the crystal orientation and segregation in the macrostructure of the ingot affect the aspect of the metal structure in the subsequent processing. The upper limit of the thickness of the ingot is not particularly limited, but typically, it may be 5000 times or less the thickness of the copper alloy material.

After the melt casting, hot rolling can be performed, then cold rolling (first cold rolling step) is performed on the raw material, and then the first solution treatment can be performed.

2-2. Second cold rolling step After the first solution treatment, a second cold rolling step can be performed. The second cold rolling step is preferably performed before the intermediate solution treatment (second solution treatment step) (that is, cold rolling before the intermediate solution treatment). In the second cold rolling step, the degree of processing is preferably 70% or more, and more preferably 80% or more. When it is 70% or more, the segregated layer of the alloying element can be thinned to reduce the distance required for the alloying element to diffuse, and a large amount of processing strain effective for homogenizing the alloying element can be introduced. The upper limit is not particularly specified, but is typically 95% or less.

In this specification, the degree of processing refers to a value calculated by the following formula.
Rolling degree (%) = 100 x (plate thickness before cold rolling-plate thickness after cold rolling) / plate thickness before cold rolling

2-3. Third cold rolling step Cold rolling can be performed before the third solution treatment (final solution treatment) (cold rolling before final solution treatment). Here, as in the second cold rolling process, by increasing the degree of processing, the segregated layer of the alloying element is thinned, the distance required for the alloying element to diffuse is reduced, and it is effective for homogenizing the alloying element. A lot of processing strain can be introduced. However, unlike the second cold rolling step, if the degree of processing is too high, a coarse recrystallized grain structure accompanied by secondary recrystallization is likely to be generated in the final solution treatment. Due to the synergistic effect of the effect of coarse recrystallized grain structure with secondary recrystallization and the effect of crystal orientation and segregation on the macrostructure of the ingot, the metallographic structure may fluctuate in the length direction.

From the above viewpoint, the workability of the third cold rolling step is preferably 50% or more, and more preferably 70% or less.

2-4. Final cold rolling step Cold rolling can be performed after the third solution treatment (final solution treatment) (final cold rolling step). Here, the strength, which is a basic characteristic of copper alloys for electronic materials used in various electronic components, is mainly adjusted.

2-5. Solution treatment The above-mentioned production method is characterized in that at least three solution treatments are performed. Of particular importance are the first solution treatment step (straight solution treatment step) and the intermediate solution treatment (second solution treatment step). In these treatment steps, it is preferable to carry out the treatment at a high temperature for a long time, that is, under the condition that the crystal grain size becomes large. This makes it possible to prevent the crystal orientation and segregation of the ingot in the macrostructure from affecting the aspect of the metal structure in subsequent processing.

However, on the other hand, when the crystal grain size is increased, a coarse recrystallized grain structure accompanied by secondary recrystallization is likely to be generated. Due to the synergistic effect of the effect of coarse recrystallized grain structure accompanied by secondary recrystallization and the effect of crystal orientation and segregation in the macrostructure of the ingot, the metal structure fluctuates and the thickness tends to fluctuate.

For the above reasons, the crystal particle size is 0.090 mm or more in the first solution treatment step (straight solution treatment step), and the crystal particle size is 0 in the intermediate solution treatment (second solution treatment step). It is preferable that the thickness is 040 mm or less. More preferably, in the first solution treatment step, the crystal grain size is 0.100 mm or more. The lower limit of the crystal particle size in the intermediate solution treatment (second solution treatment step) is not particularly limited, but may be, for example, 0.020 mm or more. The upper limit of the crystal particle size in the first solution treatment step is not particularly limited, but may be, for example, 0.150 mm or less. In order to achieve such a crystal grain size, the solution treatment can be carried out by adjusting the temperature and time for each alloy component and each plate thickness under the conditions of a temperature of 700 to 950 ° C. and a time of 1 to 600 seconds. .. Here, the higher the temperature, the larger the crystal grain size, and the longer the crystal grain size, the larger the value. Therefore, it is possible to obtain a desired crystal grain size by adjusting the temperature and time appropriately. it can.

The crystal grain size is measured based on JIS H0501 (1986). Here, the surface for measuring the crystal grain size is a surface parallel to the rolled surface. The method for measuring the crystal grain size is the "cutting method", and the direction of the line segment for cutting the surface for measuring the crystal grain size is the direction perpendicular to the rolling direction.

In the final solution treatment, it is known that the obtained metallographic structure affects various properties required for copper alloy strips for electronic and electrical parts. When only the thickness variation is considered, it is preferable that the crystal grain size is 0.020 mm or more and 0.040 mm or less, but the crystal grain size is 0.020 mm in order to have good characteristics for matters other than the thickness variation. It may be as follows. In order to achieve such a crystal particle size, the solution treatment can be carried out under the conditions of a temperature of 700 to 950 ° C. and a time of 1 to 600 seconds.

2-6. Strain Annealing After the final cold rolling, strain annealing may be performed. Strain relief annealing includes reduction of residual stress, improvement of thermal expansion and contraction characteristics, improvement of spring property (spring limit value, etc.), improvement of elongation rate in tensile test, improvement of bendability, low temperature annealing effect, and flatness. There are effects such as improvement. General conditions are a temperature of 350-650 ° C. and a time of 1-600 seconds. Within this range, an appropriate temperature and time can be set for each of the above-mentioned desired items.

3. 3. The processed copper alloy material can be pressed. Further, before and after the press working, a treatment such as plating (for example, Ni) may be performed. The processed copper alloy product that has undergone press working or the like can be used as a material for assembling electronic parts. Further, the electronic component can be used to assemble an electronic device.

(Evaluation method of thickness variation)
The thickness variation was measured by the method described above.

(Evaluation method of pressability)
A bending test (90 ° bending test) was performed with a bending angle of 90 ° in accordance with the "V block method" specified in JISZ2248 (2006) "Metallic material bending test method". The test piece had a rectangular shape with a width of 10 mm and a length of 100 mm, whose long side was parallel to the rolling direction.
In the test, a preliminary test was first conducted to determine the prescribed test force. In the preliminary test, the test piece was placed on the V block, a push metal fitting was applied to the central portion thereof, and a test force was applied to bend the test piece. After bending, the bending angle of the test piece was measured.
In the preliminary test, the test force was changed for each test piece to perform bending. When the test force was large, the bending angle of the test piece was 90 °. When the test force was small, the bending angle of the test piece was less than 90 °. The test force at which the bending angle of the test piece after the bending process was 88.5 ° to 89.5 ° was defined as the specified test force.
Next, 50 test pieces were bent by applying a test force. The test force here was the specified test force obtained in the above preliminary test, and 50 test pieces were bent with the same test force.
After bending, the bending angles were measured for 50 test pieces, and the average value and standard deviation of the bending angles were calculated.
If the standard deviation is 1% or less of the average value, it is judged that the pressability is good (○ is displayed in the table), and if the standard deviation is more than 1% of the average value, the pressability is poor (table). X is displayed inside).

(Examples 1 to 24, Comparative Examples 1 to 7)
An ingot having the composition shown in Table 1 was prepared. For this ingot, melt casting, hot rolling, first cold rolling (raw cold rolling), first solution treatment (raw solution treatment), second cold rolling (before intermediate solution treatment). Cold rolling), second solution treatment step (intermediate solution treatment), third cold rolling (cold rolling before final solution treatment), third solution treatment step (final solution treatment), aging treatment, The final cold rolling was carried out in sequence. Here, in the first solution treatment (strand solution treatment), the temperature and time are adjusted for each alloy component and each plate thickness in the range of 700 to 950 ° C. and 1 to 600 seconds, and the crystal grain size is adjusted. A solution-treated material having a thickness of 0.120 mm was obtained and subsequently treated and processed. However, for Comparative Example 6, the temperature and time were adjusted so that the crystal grain size was 0.060 mm. Then, a final cold-rolled material having a plate thickness of 0.08 mm (average value) and a width of 630 mm was obtained. However, in Example 23, the plate thickness was 0.12 mm (average value), and in Example 24, the plate thickness was 0.15 mm (average value). Then, the width was slit to 30 mm with a slitter. The thickness of the obtained strips is measured at five measuring points arranged at intervals of 60 mm in the rolling direction, the difference between the maximum value and the minimum value of the five thickness data obtained by the measurement is calculated, and this is used as copper. The degree of variation in the thickness of the alloy was used.

The thickness variation and press workability of the obtained copper alloy strip were evaluated by the above-mentioned method. The results are shown in Table 1.

In all of Examples 1 to 24, the degree of thickness variation was sufficiently suppressed. The pressability was also good.

On the other hand, in Comparative Example 1, since the ratio of ingot thickness / product thickness was low, the thickness variation exceeded the preferable range and the pressability was poor.

In Comparative Example 2, since the degree of rolling process of the second cold rolling (cold rolling before intermediate solution treatment) was low, the degree of thickness variation exceeded the preferable range and the pressability was poor.

In Comparative Example 3, since the degree of rolling in the third cold rolling step (cold rolling before the final solution treatment) was high, the degree of thickness variation exceeded the preferable range and the pressability was poor.

In Comparative Example 4, since the degree of rolling in the third cold rolling step (cold rolling before the final solution treatment) was low, the degree of thickness variation exceeded the preferable range and the pressability was poor.

Comparative Example 5 shows the ratio of ingot thickness / product thickness, the degree of rolling process of the second cold rolling (cold rolling before intermediate solution treatment), and the third cold rolling (cold rolling before final solution treatment). Since all of the rolling workability of the above was out of the preferable range, the thickness variation exceeded the preferable range and the pressability was poor.

In Comparative Example 6, since the crystal grain size of the raw material solution treatment (raw material solution treatment step) became small, the thickness variation exceeded the preferable range and the pressability was poor.

In Comparative Example 7, since the crystal grain size in the intermediate solution treatment (second solution treatment step) became large, the thickness variation exceeded the preferable range and the pressability was poor.

In the present specification, the description of "or" or "or" includes the case where only one of the options is satisfied or the case where all the options are satisfied. For example, the description of "A or B" and "A or B" includes both the case where A is satisfied and B is not satisfied, the case where B is satisfied and A is not satisfied, and the case where A is satisfied and B is satisfied. Intended to be.

The specific embodiments of the present invention have been described above. The above-described embodiment is merely a specific example of the present invention, and the present invention is not limited to the above-described embodiment. For example, the technical features disclosed in one of the above embodiments can be provided to other embodiments. Further, for a specific method, it is possible to replace some steps with the order of other steps, and an additional step may be added between the two specific steps. The scope of the present invention is defined by the claims.

Claims (6)

A total of 0.5 to 5.0% by mass of one or more of Ni and Co,
Contains 0.1 to 1.2% by mass of Si
The balance is a copper alloy material consisting of copper and unavoidable impurities.
The copper alloy material is a strip, plate or foil.
The thickness is 0.05 mm or more,
A copper alloy material having a thickness variation of 0.0 μm to 2.0 μm at five measurement points located side by side at intervals of 60 mm in a direction parallel to the rolling direction. Sn, Zn, Mg, Cr, Mn, Fe, Z r, P, Ag, copper alloy material according to claim 1, 0.005 to 3.0 mass% further containing one or more in a total amount of B. The copper alloy material according to claim 1, further containing one or more of Sn, Zn, Mg, Cr, Mn, Fe, Ti, Zr, P, Ag, and B in a total amount of 0.005 to 1.0% by mass. An electronic component comprising the copper alloy material according to any one of claims 1 to 3. An electronic device including the electronic component of claim 4. The method for producing a copper alloy material according to any one of claims 1 to 3, wherein the method is:
Melting casting process and
Hot rolling process and
The first cold rolling process and
The first solution treatment process and
Second cold rolling process and
Second solution treatment process and
Third cold rolling process and
Third solution treatment process and
Aging process and
The final cold rolling process and
Including
The workability in the second cold rolling step is 70% or more, and
The workability in the third cold rolling step is 50% or more and 70% or less.
The first solution treatment step comprises adjusting the crystal grain size to 0.090 mm or more, and the second solution treatment step includes adjusting the crystal grain size to 0.020 mm to 0.040 mm.
The method.