KR20220088412A - Copper plate material, manufacturing method thereof, and insulated substrate with copper plate material - Google Patents

Abstract

The copper plate material of the embodiment has a composition consisting of 99.96 mass% or more of Cu and unavoidable impurities, and the area ratio of crystal grains whose GAM value obtained from the crystal orientation analysis data of the SEM-EBSD method is less than 0.5° is 5% or less, and The area ratio of the crystal grains that are 0.5° or more and less than 1.0° is 50% or more.

Description

Copper plate material, manufacturing method thereof, and insulated substrate with copper plate material

This invention relates to a copper plate material, its manufacturing method, and an insulating substrate with a copper plate material.

In general, a power device that is a semiconductor element used in a power converter such as an inverter or a converter uses a high voltage and a large current, so a lot of heat is generated, and deterioration of the material is a problem. With respect to this subject, in recent years, measures for insulation and heat dissipation of power devices have been made by using an insulating substrate with a copper plate in which an insulating substrate such as a ceramic substrate having excellent insulation and heat dissipation properties is bonded to a copper plate.

The insulated substrate with a copper plate is, for example, as a defect inspection before product shipment, the presence or absence of voids of about several tens of micrometers existing at the interface between a copper substrate and an insulating substrate is investigated by ultrasonic flaw inspection. As a characteristic of ultrasonic waves, the attenuation coefficient of ultrasonic waves is proportional to the third power of the grain diameter. When coarse crystal grains (hereinafter, also referred to as coarse grains) exist in the copper sheet of the insulating substrate with a copper sheet, the attenuation coefficient of the ultrasonic wave with respect to the coarse grains becomes large compared with the surroundings of the coarse grains. As a result, in ultrasonic flaw inspection, it may be recognized as a defect also about a coarse grain together with a void, and the coarse grain in a copper plate material becomes a disturbance factor in quality control of an insulating substrate with a copper plate material. In the ultrasonic inspection, a sub-mm order area is scanned to examine the presence or absence of voids. Therefore, the presence of coarse grains in the scan region may become a disturbance factor and may affect the precision of the ultrasonic inspection.

Here, as a bonding method of an insulating substrate and a copper plate material, there are a method of bonding through a brazing material such as a silver-based brazing material, and a method of bonding using a copper eutectic reaction without passing through a brazing material. However, in this bonding method, heat treatment at a high temperature of 700°C or higher is required. This heat treatment temperature is a temperature range in which copper grain growth remarkably advances. As a result, coarse grains may be formed in the copper plate material of the insulating substrate with a copper plate material, and the precision of an ultrasonic flaw inspection falls.

Therefore, conventionally, in order to suppress the crystal grain growth after heat processing at high temperature, the method of macroscopically controlling the crystal orientation of a copper plate material is tried. For example, in Patent Document 1, an oxygen-free copper plate having a specific crystal plane and a specific diffraction peak intensity ratio in the rolled plane, and having an average crystal grain diameter of 0.4 mm or less after heat treatment under specific conditions, and a ceramic wiring including the oxygen-free copper plate A substrate is described. However, it is difficult to suppress the coarsening of the local crystal grains of a copper plate material by the macro control method of sub-mm order like patent document 1, and the precision of an ultrasonic flaw inspection may fall.

Japanese Patent Laid-Open No. 2018-204108

It is an object of the present invention to provide a copper plate material excellent in the precision of ultrasonic flaw inspection even when subjected to heat treatment and bonding to an insulating substrate, a method for manufacturing the same, and an insulating substrate with a copper plate material.

The configuration of the gist of the present invention is as follows.

[1] The area ratio of crystal grains having a composition consisting of 99.96 mass% or more of Cu and unavoidable impurities and having a GAM value obtained from crystal orientation analysis data of the SEM-EBSD method of less than 0.5° is 5% or less, and 0.5° or more and 1.0 A copper sheet material, characterized in that the area ratio of grains less than ° is 50% or more.

[2] The copper sheet material according to the above [1], wherein the area ratio of the crystal grains having a GAM value of 1.0° or more obtained from the crystal orientation analysis data obtained by the SEM-EBSD method is 40% or less.

[3] The copper sheet material according to [1] or [2], wherein the content of Cu is 99.99% by mass or more.

[4] 　The copper plate material has an average grain diameter (r) of 10 µm or more and 300 µm or less, and a maximum grain size (R) of less than 1000 µm, of crystal grains after heating at 800 ° C. for 10 minutes, The copper sheet material according to any one of [1] to [3], wherein a ratio (R/r) of the maximum grain size (R) to the average grain size (r) is 5.0 or less.

[5] 　 an insulating substrate, laminated on the insulating substrate, has a composition consisting of 99.96 mass % or more of Cu and unavoidable impurities, and has an average grain size (r) of 10 µm or more and 300 µm or less, and a maximum grain size (R) It is less than 1000 micrometers, and the ratio (R/r) of the said maximum grain diameter (R) with respect to the said average grain diameter (r) was 5.0 or less equipped with the copper plate material, The insulation board|substrate with a copper plate material.

[6] 　 The method for manufacturing a copper plate material according to any one of [1] to [4], wherein the copper ingot is obtained through a casting step (step 1) of obtaining a copper ingot from a copper material, and after the casting step (step 1), the copper ingot The homogenization heat treatment step (step 2) of performing a homogenization heat treatment for ), after the cooling step (step 4), and after the cooling step (step 4), the chamfering step (step 5) of chamfering the surface of the cooled rolled material after the chamfering step (step 5), The first cold rolling step (step 6) of performing cold rolling in which the total working ratio is 75% or more, and after the first cold rolling step (step 6), annealing in which heat treatment is performed under heating conditions of 200°C or more and 500°C or less A second cold rolling step (step 8) of performing cold rolling having a reduction ratio of 5% or more and 25% or less in one pass and one direction after the step (step 7) and the annealing step (step 7); 2 After the cold rolling step (step 8), a calibration step (step 8) of correcting with a tension leveler at an elongation rate within the range of 0.1% or more and 1.0% or less in the opposite direction to the rolling direction of the second cold rolling step (step 8) 9), characterized in that it includes, a method of manufacturing a copper plate material.

ADVANTAGE OF THE INVENTION According to this invention, even if it heat-processes and joins with an insulating substrate, the copper plate material excellent in the precision of an ultrasonic flaw inspection, its manufacturing method, and an insulating substrate with a copper plate material can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS In quality inspection property evaluation, the result of a non-destructive test and a destructive test agrees, and it is an example which has favorable test|inspection property.
2 : is an example in which a difference arises in the result of a non-destructive test and a destructive test in quality inspection property evaluation, and testability is insufficient.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on embodiment.

As a result of repeated research by the present inventors, the average grain diameter of the crystal grains in the copper plate material after heat treatment and The maximum crystal grain diameter can be simultaneously controlled, and as a result, it is found that the precision of ultrasonic inspection can be improved, and based on this knowledge, the present invention has been completed.

The copper plate material of embodiment is demonstrated. The copper plate material of the embodiment has a composition consisting of 99.96 mass% or more of Cu and unavoidable impurities, and the area ratio of crystal grains whose GAM value obtained from the crystal orientation analysis data of the SEM-EBSD method is less than 0.5° is 5% or less, and The area ratio of the crystal grains that are 0.5° or more and less than 1.0° is 50% or more.

First, the composition of a copper plate material is demonstrated. The composition of the copper plate material consists of Cu (copper) of 99.96 mass % or more and unavoidable impurities, and preferably consists of 99.99 mass % or more of Cu and unavoidable impurities. The thermal conductivity of a copper plate material improves that content of Cu is 99.96 mass % or more, and desired heat dissipation can be acquired. From this viewpoint, it is so preferable that there is much content of Cu. The copper plate material is, for example, oxygen-free copper.

In addition, with respect to a copper plate material, remainder other than Cu is an unavoidable impurity. Since some unavoidable impurities may be unavoidably contained in a manufacturing process, and depending on content may also reduce the electrical conductivity of a copper plate material and impair heat dissipation, it is preferable that content of an unavoidable impurity is small. Examples of the unavoidable impurities include Al (aluminum), Be (beryllium), Cd (cadmium), Mg (magnesium), Pb (lead), Ni (nickel), P (phosphorus), Sn (tin), Cr ( chromium), Zn (zinc), Bi (bismuth), Hg (mercury), Se (selene), and Te (tellurium). The upper limit of the content of the unavoidable impurities is preferably 10 ppm or less, more preferably 2.0 ppm or less, in total of the elements. Moreover, S (sulfur) may be contained as an unavoidable impurity, and the upper limit of content of S in this case is 20 ppm or less. Moreover, O (oxygen) may be contained as an unavoidable impurity, and the upper limit of the content of O in this case is 10 ppm or less.

Moreover, the thickness of a copper plate material is 0.1 mm or more and 1.5 mm or less, for example. When the thickness of the copper plate material is within the above range, the copper plate material can be easily bonded to the insulating substrate, and good heat dissipation can be exhibited.

Next, the GAM value will be described. The GAM (grain = average = misorientation) value is a value obtained from the crystal orientation analysis data of the SEM-EBSD method, and the distance between the measurement points within the grain boundaries separated by diagonal grain boundaries with an orientation difference of 15° or more (hereinafter also referred to as step size) is a value calculated by measuring the azimuth at 1 μm, calculating the orientation difference for each adjacent measurement point, and calculating the calculated orientation difference as an average value within the same crystal grain.

A small GAM value means a small average orientation difference within a grain, a uniform grain with very little deformation, a continuous orientation gradient, etc., and indicates that the local deformation within one grain is small. On the other hand, a large GAM value means that the average orientation difference within a crystal grain is large, and shows that the local strain within one crystal grain is large.

In the crystal orientation analysis data obtained by observing the copper plate material by the SEM-EBSD method, the area ratio of the crystal grains having a GAM value of less than 0.5° is 5% or less. If the area ratio is 5% or less, in the heat treatment at the time of lamination with an insulating substrate described later, non-uniform grain growth in the copper sheet can be avoided, so even in the case of a heat-treated copper sheet, the maximum grain size It is possible to suppress the growth of abnormal grains having a crystal grain diameter (R) of 1000 µm or more. As a result, a favorable ultrasonic flaw inspection can be performed with respect to the insulating board|substrate with a copper plate material which heat-processed and bonded the copper plate material and the insulating substrate together. When the area ratio is larger than 5%, the maximum crystal grain diameter (R) of crystal grains in the copper sheet material after heat treatment may be 1000 µm or more, and the precision of the ultrasonic flaw inspection of the insulating substrate with a copper sheet material falls.

In addition, in the crystal orientation analysis data obtained by observing the copper plate material by the SEM-EBSD method, the area ratio of crystal grains having a GAM value of 0.5° or more and less than 1.0° is 50% or more, preferably 60% or more, more preferably 70 % or more When the area ratio is 50% or more, crystal grains with minute deformation occupies more than half of the entire crystal grains of the copper plate material, and in the heat treatment at the time of lamination with an insulating substrate to be described later, uniformity in the copper plate material Since normal normal grain growth is caused, even in the case of a heat-treated copper plate, the average grain diameter (r) of crystal grains can be controlled within a range of 10 µm or more and 300 µm or less. As a result, since it can suppress that a coarse grain is formed in the copper plate material after heat processing, a favorable ultrasonic flaw inspection can be performed with respect to the insulating board|substrate with a copper plate material. The average grain diameter r may become larger than 300 micrometers in the copper plate material after heat processing that the said area ratio is less than 50 %, and the precision of the ultrasonic flaw inspection of the insulating substrate with a copper plate material falls.

Moreover, with respect to a copper plate material, the area ratio of the crystal grains whose GAM value obtained from the crystal orientation analysis data obtained by the SEM-EBSD method is 1.0 degrees or more becomes like this. Preferably it is 40 % or less, More preferably, it is 30 % or less. If the area ratio is 40% or less, the high strain state of the copper plate material can be alleviated, that is, the area ratio occupied by crystal grains having a large driving force for grain growth can be reduced. r), the maximum grain size R, and the ratio (R/r) of the maximum grain size R to the average grain size r can be easily controlled within a predetermined range. As a result, the precision of the ultrasonic flaw inspection with respect to the insulated board|substrate with a copper plate material improves further.

In this way, the crystal state (average grain size (r), maximum grain size (R), and ratio (R/r)) in the copper sheet material after heating depends on the crystal structure of the copper sheet material before heating. In particular, the local strain in the grains before the heat treatment can be a driving force for producing coarse grains after the heat treatment. Therefore, in this embodiment, the crystal structure is controlled by adjusting the area ratio of the crystal grains having a predetermined GAM value to the copper sheet material before heat treatment within a predetermined range.

The GAM value is calculated from crystal orientation data continuously measured using the EBSD detector attached to a high-resolution scanning analytical electron microscope (manufactured by Nippon Electronics Co., Ltd., JSM-7001FA) using analysis software (manufactured by TSL, OIM Analysis). It can be obtained from one crystal orientation analysis data. "EBSD" is an abbreviation of Electron BackScatter Diffraction, and is a crystal orientation analysis technique using reflected electron Kikuchi ray diffraction generated when an electron beam is irradiated to a copper plate material as a sample in a scanning electron microscope (SEM). "OIM Analysis" is analysis software for data measured by EBSD. The measurement is performed with a step size of 1 µm in an approximately 400 µm×800 µm field of view. A measurement area|region is the surface mirror-finished by electrolytic polishing with respect to the surface of a copper plate material. As for the area ratio of grains of GAM values within a predetermined range, GAM values of 0° or more and less than 0.25° are the first division, 15 divisions of 0.25° each, GAM values of 0° or more and less than 3.75° are the measurement targets, and SEM - It can be calculated from the sum of the area ratios of the crystal grains of each division occupied in the whole SEM image obtained by EBSD method.

As mentioned above, the copper plate material which adjusted the area ratio of the crystal grains of a predetermined GAM value so that it might become in a predetermined range is laminated|stacked on the insulating substrate by performing the heat processing mentioned later. As general heat treatment conditions, the heating atmosphere is an argon atmosphere, the heating temperature is 800°C, the heating time is 10 minutes, and the temperature rise temperature is 10°C/min. Regarding the crystal state of the copper plate material after heat treatment, the average grain diameter (r) of the crystal grains is 10 µm or more and 300 µm or less, preferably 10 µm or more and 200 µm or less, and the maximum grain size (R) of the crystal grains is less than 1000 µm, The ratio (R/r) of the maximum grain size (R) to the average grain size (r) is 5.0 or less.

Thus, the copper plate material of embodiment adjusted the area ratio of the crystal grains of a predetermined GAM value so that it might become in a predetermined range. As a result, even when the copper sheet material is heated under the above conditions, coarse grains formed in the copper sheet material after heating are suppressed, and the crystal grains after a thermal history of 800°C for 10 minutes can be made into a crystal state within the predetermined range, so that after heating A good ultrasonic flaw inspection can be performed with respect to a copper plate material.

On the other hand, if the conventional copper plate material in which the area ratio of crystal grains having a predetermined GAM value is not adjusted to be within the predetermined range is heated under the above conditions, since a large number of coarse grains exist in the copper plate material after heating, the copper plate material after heating The precision of ultrasonic inspection is reduced.

Next, the manufacturing method of the copper plate material of embodiment is demonstrated. The manufacturing method of the copper plate material of embodiment is a homogenization heat treatment process (process 2) of a casting process (process 1) which obtains a copper ingot from a copper raw material, and homogenization heat processing with respect to a copper ingot after a casting process (process 1) ) and after the homogenization heat treatment process (process 2), a hot rolling process (process 3) of performing hot rolling, a cooling process (process 4) of performing cooling after the hot rolling process (process 3), and a cooling process After (Step 4), the chamfering step (Step 5) of chamfering the surface of the cooled rolled material, and the first cold rolling step (Step 5) of performing cold rolling with a total working ratio of 75% or more after the chamfering step (Step 5) 6) and after the first cold rolling step (step 6), an annealing step (step 7) in which heat treatment is performed under heating conditions of 200° C. or more and 500° C. or less, and after the annealing step (step 7), the rolling reduction is 5% 2nd cold rolling process (process 8) which performs cold rolling of 25% or more in one pass and one direction, and 2nd cold rolling process (process 8), by a tension leveler, 2nd cold rolling process (process) In the direction opposite to the rolling direction of 8), a calibration step (step 9) of performing calibration at an elongation rate within the range of 0.1% or more and 1.0% or less is included.

In a casting process (process 1), a copper ingot of a predetermined shape is obtained by melt|dissolving and casting a copper raw material. For example, melting is performed in the atmosphere using a high frequency melting furnace. The kind of copper material, casting conditions, etc. are suitably set so that the copper ingot obtained may have a composition which consists of Cu of 99.96 mass % or more and an unavoidable impurity.

In the homogenization heat treatment step (step 2), the copper ingot obtained in the casting step (step 1) is subjected to a homogenization heat treatment under heating conditions of 700°C or more and 1000°C or less, 10 minutes or more and 10 hours or less. The homogenization heat treatment step (Step 2) is performed, for example, in an inert gas atmosphere.

In the hot-rolling process (process 3), a hot-rolling process is performed so that the total working ratio may be 10% or more and 98% or less, Preferably, it may become 90% or more and 98% or less.

In a cooling process (process 4), it cools at a cooling rate of 10 degrees C/sec or more.

In a chamfering process (process 5), a predetermined thickness of about 1 mm or more and about 2 mm is chamfered from the surface of the cooled rolling material, for example. By performing the chamfering process (process 5), an oxide film is removed from the surface of the cooled rolling material.

In the 1st cold rolling process (process 6), cold rolling is performed so that a total working ratio may become 75 % or more.

In the annealing step (step 7), heat treatment is performed under heating conditions of 200°C or higher and 500°C or lower. For example, the temperature increase rate is 1°C/sec or more and 100°C/sec or less, the holding time of the heat treatment temperature is 10 seconds or more and less than 5 hours, and the cooling rate is 1°C/sec or more and 50°C/sec or less. Uniform recrystallization grains can be obtained by implementing an annealing process (process 7).

In the 2nd cold rolling process (process 8), the cold rolling process of 5% or more and 25% or less is made into only one pass and one direction. By implementing the 2nd cold rolling process (process 8), distortion is introduce|transduced uniformly in a rolling material. When the reduction ratio is less than 5%, the area ratio of crystal grains having a GAM value of less than 0.5° with respect to the copper sheet material to be manufactured becomes greater than 5%. Further, when the reduction ratio is larger than 25%, the area ratio of the crystal grains having a GAM value of 1.0° or more increases. In addition, when cold rolling is performed in multiple passes, the strain in the copper sheet material is dispersed and the non-uniformity of strain occurs. Therefore, the area ratio of grains with a GAM value of less than 0.5° and the area ratio of crystal grains with a GAM value of 1.0° or more each increase

In a correction process (process 9), a tension leveler corrects so that it may become the elongation rate within the range of 0.1 % or more and 1.0 % or less along a direction opposite to the rolling direction of a 2nd cold rolling process (process 8). When only the 2nd cold rolling process (process 8), ie, a correction process (process 9) is not implemented, the ratio which becomes in the predetermined range with respect to the area ratio of the crystal grains of a predetermined GAM value is small. Therefore, by implementing a correction process (process 9), a distortion can be adjusted and the ratio at which the area ratio of the crystal grains of a predetermined GAM value becomes in a predetermined range can be increased. When the correction is performed in the rolling direction and the forward direction of the second cold rolling step (step 8), the orientation difference within the crystal grains is added, and the area ratio of the crystal grains having a GAM value of 1.0° or more in the copper sheet material increases. Moreover, when the elongation is less than 0.1%, the GAM value of the copper sheet material is not adjusted, and it becomes difficult to control the area ratio of the crystal grains having a GAM value of less than 0.5° to 5% or less. Further, when the elongation is greater than 1.0%, the area ratio of the crystal grains having a GAM value of 1.0° or more increases.

Next, the insulated board|substrate with a copper plate of embodiment is demonstrated. The insulating substrate with a copper plate of embodiment is laminated|stacked on an insulating substrate and an insulating substrate, has a composition which consists of 99.96 mass % or more Cu and unavoidable impurity, and has an average crystal grain diameter r of 10 micrometers or more and 300 micrometers or less, maximum A copper plate material having a grain size (R) of less than 1000 µm and a ratio (R/r) of the maximum grain size (R) to the average grain size (r) of 5.0 or less is provided.

The insulating substrate supporting the copper plate material is a substrate having electrical insulation properties, such as a ceramic substrate. The ceramic substrate is preferably a substrate mainly composed of at least one type of ceramic selected from the group consisting of aluminum nitride, silicon nitride, alumina and zirconium oxide, for example. Although the thickness of a ceramic substrate is not specifically limited, For example, Preferably they are 0.05 mm or more and 2.00 mm or less, More preferably, they are 0.20 mm or more and 1.00 mm or less.

A copper plate is provided on the surface of the insulating substrate. The copper plate material may be joined to the insulating substrate through a bonding material such as a brazing material or solder, or may be directly bonded to the insulating substrate by using the eutectic reaction of the copper sheet material without passing through the bonding material. Moreover, a copper plate material may be laminated|stacked also on the back surface of an insulating substrate.

As a method of laminating a copper plate material on the surface of an insulating substrate, when a bonding material is used, a copper sheet is installed on the surface of the insulating substrate through a bonding material, or when a bonding material is not used, a copper sheet material on the surface of the insulating substrate is directly installed, and thereafter, heat treatment under predetermined conditions is performed. As general heat treatment conditions, in an argon atmosphere tubular furnace, heating is carried out at a temperature of 800°C or more and 850°C or less, a time period of 10 minutes or more and 60 minutes or less, and a temperature increase rate of 2-20°C/min. Thereby, a copper plate material is joined on the surface of an insulating substrate. The copper plate material joined on the insulating substrate has a composition consisting of 99.96 mass % or more of Cu and an unavoidable impurity as mentioned above. Moreover, the copper plate material has an average grain diameter (r) of 10 µm or more and 300 µm or less, a maximum grain diameter (R) of less than 1000 µm, and the ratio of the maximum grain diameter (R) to the average grain diameter (r) ( R/r) is 5.0 or less. Since the formation of coarse grains is suppressed in the copper plate material of the insulated substrate with a copper plate material whose average crystal grain diameter (r), maximum grain diameter (R), and ratio (R/r) are controlled within the said range, since formation of a copper plate material adheres A good ultrasonic flaw inspection can be performed with respect to an insulated substrate. Furthermore, since the crystal grains of the copper plate material of the insulated substrate with a copper plate material are fine and uniform, and the crystal grain boundary density in a copper plate material is uniform, the favorable bondability of the copper plate material in an insulating substrate with a copper plate material and an insulating substrate is shown. This insulated substrate with a copper plate material is used suitably for the semiconductor element for power devices by which the precision of an ultrasonic flaw inspection is calculated|required.

According to the embodiment described above, it is possible to manufacture a copper sheet material controlled so that the area ratio of crystal grains having a predetermined GAM value is within a predetermined range. Even if the copper plate material is heat-treated under the predetermined conditions, in the heated copper plate material, the average grain diameter (r), the maximum grain diameter (R) and the ratio (R/r) of the crystal grains are small, that is, the coarse grains formation is inhibited. Therefore, even if a copper plate material and an insulated substrate are joined using a copper eutectic reaction through or without a brazing material such as a silver-based brazing material, the obtained insulating substrate with a copper plate material is excellent in bonding properties between the copper plate material and the insulating substrate. , it is possible to increase the accuracy of quality inspection by ultrasonic inspection.

As mentioned above, although the embodiment has been described, the present invention is not limited to the above embodiment, but includes all aspects included in the concept and claims of the present invention, and various modifications can be made within the scope of the present invention. have.

[Example]

Next, although an Example and a comparative example are demonstrated, this invention is not limited to these Examples.

(Examples 1 to 9 and Comparative Examples 1 to 6)

A copper raw material was melt|dissolved with the high frequency melting furnace under air|atmosphere, this was cast, and the copper ingot of Cu and unavoidable impurity content shown in Table 1 was obtained. Next, for the copper ingot, after homogenizing heat treatment under heating conditions of 700 ° C or more and 1000 ° C or less, 10 minutes or more and 10 hours or less, hot rolling is performed so that the total working rate is 90% or more and 98% or less, It was cooled to room temperature at a cooling rate of 10° C./sec or more. Since the oxide film was formed on the surface of the cooled rolling material, this oxide film was chamfered. Next, after cold-rolling so that the total working ratio is 75% or more, heat treatment was performed under heating conditions of 200°C or more and 500°C or less for 2 hours. After that, after performing the second cold rolling step (step 8) in one direction with the reduction ratio and number of passes shown in Table 2, the calibration step (step 9) is performed with a tension leveler in the direction and elongation ratio shown in Table 2 Thus, a copper plate material having a thickness of 0.5 mm was obtained. Next, a copper plate cut to a length of 50 mm and a width of 50 mm through an Ag-Cu-Ti-based brazing material is placed on one side of the silicon nitride plate, which is an insulating substrate, from room temperature in an argon atmosphere furnace. After heating at a temperature increase rate of 10°C/min and reaching 800°C, after holding for 10 minutes, it was cooled at a cooling rate of 10°C/min to obtain an insulating substrate with a copper plate material. In addition, in Table 1, "-" indicates that it is less than the detection limit of the measurement.

[evaluation]

The following evaluation was performed about the copper plate material obtained by the said Example and the comparative example, and the insulating board|substrate with a copper plate material. The results are shown in Table 3.

[1]　GAM value and area ratio

The GAM value is crystal orientation data continuously measured using an EBSD detector attached to a high-resolution scanning analytical electron microscope (manufactured by Nippon Electronics Co., Ltd., JSM-7001FA) for the copper plate after the calibration process obtained in the above examples and comparative examples. from the crystal orientation analysis data calculated using analysis software (manufactured by TSL, OIM Analysis). The measurement was performed with a step size of 1 µm in a 400 µm×800 µm field of view. The measurement area|region was made into the surface mirror-finished by electrolytic polishing with respect to the surface of a copper plate material. As for the area ratio of grains of GAM values within a predetermined range, GAM values of 0° or more and less than 0.25° are the first division, 15 divisions of 0.25° each, GAM values of 0° or more and less than 3.75° are the measurement targets, SEM - It was computed from the sum total of the area ratio of the crystal grain of each division which occupies for the whole SEM image obtained by EBSD method. The area ratio measured 5 arbitrary places, and made it the average value.

[2]　Average grain diameter after heat treatment (r)

After mirror-polishing the surface of the copper plate material in the insulating substrate with copper plate material obtained in the above Examples and Comparative Examples, followed by etching with an aqueous chromic acid solution, a metallurgical microscope (manufactured by Olympus Co., Ltd., System Inverted Metallurgical Microscope GX53) was observed using From the obtained microscope image, in accordance with the cutting method of JIS H0501, the number of crystal grains completely cut by a line segment was counted in the rolling direction and the direction perpendicular to a rolling direction, respectively, and the average value was computed. And five arbitrary places were measured, and the average value was made into the average crystal grain diameter (r). In addition, with respect to the average grain size (r), the following ranking was made. When the average grain size r is 10 µm or more and less than 300 µm, coarse grain formation in the copper plate material of the insulating substrate with a copper plate material is suppressed. In particular, when the average grain diameter (r) is 10 µm or more and less than 200 µm, coarse grain formation in the copper plate material is further suppressed. On the other hand, when the average grain size r is more than 300 µm, coarse grains are easily formed in the copper plate material of the insulating substrate with a copper plate material.

◎: average grain diameter (r) of 10 µm or more and 200 µm or less

○: Average grain diameter (r) is more than 200㎛ 300㎛ or less

×: the average grain diameter (r) exceeds 300㎛

[3]　Maximum grain diameter after heat treatment (R)

From the microscope image used for the average crystal grain diameter (r), the cut length of the crystal grain was determined for the one having the largest crystal grain diameter, and the value was set as the maximum crystal grain diameter (R).

[4]　Quality inspection

The insulated substrates with copper plates obtained in Examples and Comparative Examples were subjected to quality inspection according to the ultrasonic flaw detection method using an ultrasonic imaging apparatus (manufactured by Hitachi Power Solutions, FineSAT III). After setting the insulating substrate with a copper plate in the water tank of the ultrasonic imaging device, the probe height is adjusted to focus on the interface between the insulating substrate and the copper plate, and the entire insulating substrate with a copper plate is scanned, ultrasonic flaw detection got a burn A probe for a frequency of 25 MHz was used.

Here, in the ultrasonic flaw detection method, which is a non-destructive test, if coarse grains or voids of about several tens of μm exist, due to the difference in material density, ultrasonic waves are strongly reflected in the coarse grains or voids, and as a result, coarse grains or voids are It is displayed as a white dot on the ultrasonic flaw image. Then, as a destructive inspection, cross-sectional observation by SEM was performed about 10 white spots on an ultrasonic flaw detection image, and the white point performed coarse grain or void determination. In cross-sectional observation by SEM, at the interface between the copper substrate 1 and the ceramic substrate 2, as shown in FIG. 1, a void 3 in the copper substrate 1 with a width of 10 µm or more and a height of 10 µm or more. is observed, the white point is a void, the results of the non-destructive inspection and the destructive inspection match, and the quality inspection property is judged to be good, and as shown in FIG. 2 , the copper substrate has a width of 10 µm or more and a height of 10 µm or more When no voids were observed, the white dots were coarse grains, and the results of the non-destructive and destructive tests differed, and it was judged that the quality inspection properties were poor. And the following ranking was performed about quality inspection property. When 9 white dots were voids, that is, when one white dot was coarse, and all white dots were voids, ie, all white dots were not coarse, it was judged that the quality inspection according to the ultrasonic inspection was performed normally. On the other hand, when less than 8 white dots are voids, that is, when two or more white dots are coarse grains, it was determined that the quality inspection according to the ultrasonic flaw detection method was not performed normally.

◎: all white dots are voids

○: 9 white dots are voids

×: 8 or less white dots are voids

As shown in Tables 1 to 3, in Examples 1 to 9, the area ratio of crystal grains with a predetermined GAM value is controlled within a predetermined range, and the average crystal grain diameter (r), the maximum crystal grain diameter (R), and the ratio (R/r) ) were controlled within a predetermined range, so the quality inspection property was good.

On the other hand, in Comparative Example 1, since the reduction ratio of the second cold rolling process (Step 8) was less than 5%, the area ratio of the crystal grains of the predetermined GAM value and the maximum grain diameter (R) were not controlled within the predetermined range, and the quality Inspection was poor. Further, in Comparative Example 2, since the reduction ratio in the second cold rolling step (Step 8) was more than 25%, the area ratio of the crystal grains of the predetermined GAM value, the average crystal grain diameter (r), the maximum crystal grain diameter (R) and the ratio (R/r) was not controlled within a predetermined range, and the quality inspection property was poor. Further, in Comparative Example 3, the number of passes in the second cold rolling process (Step 8) was in the same direction, but since there were multiple passes, the area ratio of grains with a given GAM value and the maximum grain diameter (R) are not controlled within a prescribed range. No, the quality inspection performance was poor. In Comparative Example 4, since the direction of the calibration step (step 9) was forward, the area ratio of crystal grains with a predetermined GAM value and the maximum crystal grain diameter R were not controlled within the predetermined range, resulting in poor quality inspection properties. Further, in Comparative Example 5, since the elongation rate in the calibration step (Step 9) was less than 0.1%, the area ratio of the crystal grains of the predetermined GAM value, the maximum crystal grain diameter (R), and the ratio (R/r) were not controlled within the predetermined range. No, the quality inspection performance was poor. Further, in Comparative Example 6, since the elongation rate in the calibration step (step 9) was more than 1.0%, the area ratio of the crystal grains of the predetermined GAM value, the average crystal grain diameter (r), the maximum crystal grain diameter (R), and the ratio (R/r) ) was not controlled within a predetermined range, resulting in poor quality inspection properties.

Claims (6)

It has a composition consisting of 99.96 mass % or more of Cu and unavoidable impurities,
The area ratio of grains whose GAM value obtained from the crystal orientation analysis data of the SEM-EBSD method is less than 0.5° is 5% or less, and the area ratio of crystal grains that are 0.5° or more and less than 1.0° is 50% or more, Copper, characterized in that plate. The method of claim 1,
The area ratio of the crystal grains having a GAM value of 1.0° or more obtained from the crystal orientation analysis data obtained by the SEM-EBSD method is 40% or less, a copper sheet material. 3. The method of claim 1 or 2,
Copper sheet material whose content of Cu is 99.99 mass % or more. 4. The method according to any one of claims 1 to 3,
The copper plate material has an average grain diameter (r) of 10 µm or more and 300 µm or less, and a maximum grain size (R) of less than 1000 µm, of crystal grains after heating at 800° C. for 10 minutes, and the average grain size The ratio (R/r) of the maximum grain diameter (R) to the diameter (r) is 5.0 or less, a copper sheet material. An insulating substrate and laminated formation on the insulating substrate, having a composition consisting of 99.96 mass % or more of Cu and unavoidable impurities, and an average grain size (r) of 10 µm or more and 300 µm or less, and a maximum grain size (R) of less than 1000 µm and a copper plate having a ratio (R/r) of the maximum grain diameter (R) to the average grain diameter (r) of 5.0 or less. A casting process (process 1) of obtaining a copper ingot from a copper material;
A homogenization heat treatment step (step 2) of performing a homogenization heat treatment on the copper ingot after the casting step (step 1);
After the homogenization heat treatment step (Step 2), a hot rolling step of performing hot rolling (Step 3);
A cooling step (step 4) of performing cooling after the hot rolling step (step 3);
After the cooling step (step 4), a chamfering step (step 5) of chamfering the surface of the cooled rolled material;
A first cold rolling step (step 6) of performing cold rolling with a total working ratio of 75% or more after the chamfering step (step 5);
After the first cold rolling step (Step 6), an annealing step (Step 7) of performing heat treatment under heating conditions of 200°C or higher and 500°C or lower;
a second cold rolling step (step 8) of performing cold rolling with a reduction ratio of 5% or more and 25% or less in one pass and one direction after the annealing step (step 7);
After the second cold rolling process (Step 8), a tension leveler is used in the direction opposite to the rolling direction of the second cold rolling process (Step 8), a calibration step of correcting at an elongation rate within the range of 0.1% or more and 1.0% or less (Process 9),
characterized in that it comprises,
The manufacturing method of the copper plate material in any one of Claims 1-4.

Images