Heat-resistant oxygen-free copper strip and its application in the preparation of ceramic copper-clad laminates for IGBT modules

Abstract

This invention provides a heat-resistant oxygen-free copper strip and its application in the preparation of ceramic copper-clad laminates for IGBT modules, relating to the field of copper alloy technology. The heat-resistant oxygen-free copper strip provided by this invention comprises, by mass percentage: 0.001%~0.1% Ag, 0.001%~0.1% La, with the balance being Cu. The preparation method includes: batching the materials according to the mass percentages, followed by sequential melting, casting, hot rolling, first cold rolling, first annealing, second cold rolling, second annealing, and third cold rolling to obtain the heat-resistant oxygen-free copper strip. This heat-resistant oxygen-free copper strip exhibits a conductivity ≥98% IACS, an oxygen content ≤20ppm, a hardness ≥100HV, a grain size ≤0.07mm after holding at 900℃ for 30min, and a grain size ≤0.08mm after holding at 1065℃ for 3min, effectively solving the problem of easy welding failure between oxygen-free copper and ceramic in IGBT module ceramic copper-clad laminates.

Description

Technical Field

[0001] This invention relates to the field of copper alloy technology, and in particular to a heat-resistant oxygen-free copper strip and its application in the preparation of ceramic copper-clad laminates for IGBT modules. Background Technology

[0002] An IGBT (Insulated Gate Bipolar Transistor) module is a composite power semiconductor device formed by packaging an IGBT chip and a freewheeling diode. It combines the high input impedance of a MOSFET with the low on-state voltage drop of a bipolar transistor. The module is packaged using a heat-dissipating substrate, a ceramic copper-clad plate, and a heat dissipation structure. It includes drive circuits, protection circuits, and other components, covering a voltage range of 600V-6500V and a current capacity of up to 3600A. It is mainly used in high-power industrial frequency converters, welding machines, new energy vehicles (motor controllers, vehicle air conditioners, charging piles), rail transit equipment, white goods, photovoltaics, and wind power.

[0003] The copper cladding process in ceramic-coated copper (CCC) boards requires bonding between the copper and ceramic substrates at high temperatures. However, after high-temperature heat treatment, the copper grains grow rapidly, with grain sizes reaching millimeter levels. This results in an "orange peel" texture on the bonding surface between the copper and ceramic substrates, as well as on their free surfaces, increasing the surface roughness of the copper. On one hand, the increased roughness of the bonding surface widens the gap between the copper and ceramic substrates, leading to reduced copper / ceramic bonding strength or even bonding failure. On the other hand, the increased roughness of the free surfaces also negatively impacts subsequent etching, cleaning, and welding processes, resulting in reduced copper / component weld strength or even welding failure.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The primary objective of this invention is to provide a heat-resistant oxygen-free copper strip to solve the aforementioned technical problems.

[0006] The second objective of this invention is to provide the application of the above-mentioned heat-resistant oxygen-free copper strip in the preparation of ceramic copper-clad laminates for IGBT modules.

[0007] To achieve the above objectives, the following technical solution is adopted:

[0008] In a first aspect, the present invention provides a heat-resistant oxygen-free copper strip, comprising, by mass percentage: 0.001%~0.1% Ag, 0.001%~0.1% La, with the balance being Cu;

[0009] The preparation method of the heat-resistant oxygen-free copper strip includes the following steps:

[0010] The ingredients are proportioned according to mass percentage, and then smelting, casting, hot rolling, first cold rolling, first annealing, second cold rolling, second annealing and third cold rolling are carried out in sequence to prepare heat-resistant oxygen-free copper strip.

[0011] The hot rolling includes: heating the cast ingot to 800~900℃ and then hot rolling it, wherein the initial rolling temperature is 700~800℃ and the final rolling temperature is 400~600℃.

[0012] The temperature of the first annealing is 400~600℃, and the holding time is 0.5~12h;

[0013] The second annealing temperature is 450~550℃, and the holding time is 0.5~6h.

[0014] As a further technical solution, the melting temperature is 1150~1200℃.

[0015] As a further technical solution, the casting temperature is 1150~1190℃ and the casting speed is 50~100mm / min.

[0016] As a further technical solution, the total processing rate of the hot rolling is 70%~95%.

[0017] As a further technical solution, the process after hot rolling also includes milling.

[0018] As a further technical solution, the first cold rolling process consists of 5 to 9 passes, with a single pass processing rate of 15% to 40% and a total processing rate of 60% to 90%.

[0019] As a further technical solution, the second cold rolling process consists of 5 to 9 passes, with a single pass processing rate of 20% to 35% and a total processing rate of 70% to 85%.

[0020] As a further technical solution, the third cold rolling process consists of 2 to 3 passes, with a single pass processing rate of 10% to 25%.

[0021] As a further technical solution, the third cold rolling process also includes tension straightening;

[0022] The process parameters for the bending straightening include: unwinding tension of 10~45 N / mm. 2 The winding tension is 18~60 N / mm. 2 The entry point ranges from 0.05% to 0.3%.

[0023] Secondly, the present invention provides the application of the above-mentioned heat-resistant oxygen-free copper strip in the preparation of ceramic copper-clad laminates for IGBT modules.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention, based on TU2 oxygen-free copper, adds trace amounts of alloying elements Ag and La, and obtains heat-resistant oxygen-free copper strip through smelting, casting, hot rolling, first cold rolling, first annealing, second cold rolling, second annealing, and third cold rolling. This heat-resistant oxygen-free copper strip has a conductivity ≥98% IACS, oxygen content ≤20ppm, hardness ≥100HV, grain size ≤0.07mm after holding at 900℃ for 30min, and grain size ≤0.08mm after holding at 1065℃ for 3min. It can meet the needs of IGBT development in high-power industrial frequency converters, welding machines, new energy vehicles (motor controllers, vehicle air conditioners, charging piles), rail transit equipment, white goods, photovoltaics, wind power, and other fields, and can solve the problem of easy welding failure between oxygen-free copper and ceramic in IGBT module ceramic copper-clad laminates. Detailed Implementation

[0026] The embodiments and examples of the present invention will be described in detail below. However, those skilled in the art will understand that the following embodiments and examples are for illustrative purposes only and should not be considered as limiting the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Unless otherwise specified, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0027] In a first aspect, the present invention provides a heat-resistant oxygen-free copper strip, mainly composed of Ag, La and Cu. The mass percentage of Ag can be, for example, 0.001%, 0.01%, or 0.1%; the mass percentage of La can be, for example, 0.001%, 0.01%, or 0.1%.

[0028] The preparation method of the heat-resistant oxygen-free copper strip includes the following steps:

[0029] The ingredients are proportioned according to mass percentage, and then smelting, casting, hot rolling, first cold rolling, first annealing, second cold rolling, second annealing and third cold rolling are carried out in sequence to prepare heat-resistant oxygen-free copper strip.

[0030] The hot rolling includes: heating the cast ingot to 800~900℃ (for example, but not limited to 800℃, 850℃ or 900℃), and then hot rolling it. The initial rolling temperature of the hot rolling can be, for example, but not limited to 700℃, 750℃ or 800℃, and the final rolling temperature can be, for example, but not limited to 400℃, 500℃ or 600℃.

[0031] The temperature of the first annealing can be, for example, but not limited to, 400°C, 500°C or 600°C, and the holding time can be, for example, but not limited to, 0.5h, 5h or 12h;

[0032] The temperature of the second annealing can be, for example, but not limited to, 450°C, 500°C, or 550°C, and the holding time can be, for example, but not limited to, 0.5h, 3h, or 6h.

[0033] The inventors discovered that Ag has a certain solid solubility in copper, allowing it to act as solute atoms that segregate at grain boundaries, suppressing grain growth by pinning grain boundary migration. Simultaneously, Ag can increase the recrystallization temperature of copper, slowing down the recrystallization process and thus inhibiting rapid grain coarsening at high temperatures. However, Ag has a relatively low melting point (approximately 961°C), and its suppressive effect weakens at extreme temperatures approaching or exceeding its melting point. Therefore, La was introduced. La is an active rare earth element that readily forms high-melting-point nanoscale rare earth compound particles with impurities in copper. These compound particles hinder grain growth by pinning grain boundaries; furthermore, their high melting point allows them to remain stable even near the matrix melting point, providing a more durable pinning force. La significantly affects conductivity; while excessive La can enhance copper's ability to suppress grain growth at high temperatures, it also reduces copper's conductivity. Therefore, this invention selects Ag and La to work synergistically. Ag inhibits grain growth at medium and high temperatures through solid solution effect, while La provides stability at ultra-high temperatures through second-phase particles. The combination of the two produces a synergistic strengthening effect.

[0034] Because the La-formed compound particles are highly stable and remain almost unchanged throughout the preparation process, the parameters used in the preparation process mainly affect the heat resistance by influencing the segregation of Ag at the grain boundaries.

[0035] Hot rolling is a crucial step in establishing the initial deformed microstructure, and its final rolling temperature determines the grain size and stored energy in the hot-rolled state. If the final rolling temperature is too high: grains grow rapidly at high temperatures, resulting in coarse hot-rolled grains. Coarse grains mean a smaller total grain boundary area per unit volume, reducing the total amount of "interfaces" available for Ag segregation during subsequent annealing, leading to a decrease in overall pinning effect. If the final rolling temperature is too low: dynamic recrystallization is insufficient or completely suppressed, resulting in an extremely high accumulation of deformation stored energy (high dislocation density) within the material. This high stored energy is difficult to release even after two subsequent annealing processes, and will eventually be released in the high-temperature environment of the application process, acting as a driving force to accelerate the grain recovery and recrystallization process, leading to even larger grains.

[0036] Annealing is a core step in controlling the recrystallization structure and the segregation state of Ag atoms; deviations in temperature will affect both simultaneously. When the annealing temperature is too high: thermodynamically, grain boundary segregation is an exothermic process. Increasing the temperature reduces the equilibrium segregation concentration of Ag at the grain boundaries, causing excessive Ag atoms to return from the grain boundaries to the interior, resulting in a decrease in the number of effectively pinned silver atoms at the grain boundaries and a sharp drop in pinning force. Microstructurally, the recrystallization process is rapid, and the grains coarsen quickly at high temperatures. Although Ag atoms diffuse rapidly and can quickly segregate, the low thermodynamic equilibrium concentration and weak pinning force cannot prevent large grains from engulfing smaller grains. Excessively high annealing temperatures ultimately result in a structure with weak pinning force and coarse grains, which exhibits poor stability at high temperatures of 900℃ and 1065℃. When the annealing temperature is too low: Kinetically, the diffusion rate of Ag atoms is too slow, failing to fully diffuse to the grain boundaries to complete segregation, resulting in an actual segregation concentration far lower than the theoretical equilibrium concentration, leading to poor grain boundary pinning. Microstructurally, recrystallization is insufficient or absent, leaving a large amount of stored deformation energy within the microstructure. This stored energy will eventually be released in the high-temperature environment of the application process, acting as a driving force to accelerate grain recovery and recrystallization, resulting in larger grains. When the annealing temperature is too low, an unstable microstructure with weak pinning and high driving force is ultimately obtained, leading to rapid grain growth at high temperatures. Primary and secondary annealing are indispensable "regulation" steps. They not only reshape the grain structure but, more importantly, activate and optimize the grain boundary segregation effect of silver, thereby forming stable pinning at high temperatures. Omitting these steps will degenerate the material into a high-driving-force, low-resistance system, significantly accelerating grain growth at high temperatures.

[0037] This invention, based on TU2 oxygen-free copper, adds trace amounts of alloying elements Ag and La, and obtains heat-resistant oxygen-free copper strip through smelting, casting, hot rolling, first cold rolling, first annealing, second cold rolling, second annealing, and third cold rolling. This heat-resistant oxygen-free copper strip has a conductivity ≥98% IACS, oxygen content ≤20ppm, hardness ≥100HV, grain size ≤0.07mm after holding at 900℃ for 30min, and grain size ≤0.08mm after holding at 1065℃ for 3min. It can meet the needs of IGBT development in high-power industrial frequency converters, welding machines, new energy vehicles (motor controllers, vehicle air conditioners, charging piles), rail transit equipment, white goods, photovoltaics, wind power, and other fields, and can solve the problem of easy welding failure between oxygen-free copper and ceramic in IGBT module ceramic copper-clad laminates.

[0038] In some alternative embodiments, the melting temperature may be, for example, but not limited to, 1150°C, 1180°C, or 1200°C.

[0039] In some alternative embodiments, the casting temperature may be, for example, but not limited to, 1150°C, 1170°C or 1190°C, and the casting speed may be, for example, but not limited to, 50 mm / min, 80 mm / min or 100 mm / min.

[0040] In some alternative implementations, the total processing rate of the hot rolling can be, for example, but not limited to, 70%, 80% or 95%.

[0041] In some optional embodiments, the hot rolling is followed by water cooling. The present invention does not limit the specific method of water cooling; any method well-known to those skilled in the art can be used.

[0042] In some optional embodiments, the hot rolling process further includes milling. The present invention does not limit the specific milling technique; methods well known to those skilled in the art can be used.

[0043] In some optional embodiments, the first cold rolling process may be, for example, but not limited to, 5, 7 or 9 passes, with a single pass processing rate in the range of 15% to 40%, for example, 15%, 30% or 40%, and the total processing rate may be, for example, but not limited to, 60%, 75% or 90%.

[0044] In some optional embodiments, the first annealing is followed by cleaning. The specific operation method is not limited and any method known to those skilled in the art can be used.

[0045] In some optional embodiments, the second cold rolling process may be, for example, but not limited to, 5, 7 or 9 passes, with a single pass processing rate in the range of 20% to 35%, for example, 20%, 30% or 35%, and the total processing rate may be, for example, but not limited to 70%, 80% or 85%.

[0046] In some optional embodiments, the second annealing is followed by cleaning. The specific operation method is not limited and any method known to those skilled in the art can be used.

[0047] In some optional embodiments, the third cold rolling process consists of 2 to 3 passes, with a single pass processing rate in the range of 10% to 25%, for example, 10%, 20% or 25%.

[0048] In some alternative implementations, the third cold rolling process further includes tension straightening;

[0049] The process parameters for bending straightening include: unwinding tension, for example, but not limited to, 10 N / mm. 2 20N / mm 2Or 45N / mm 2 The winding tension can be, for example, but is not limited to, 18 N / mm. 2 40N / mm 2 Or 60N / mm 2 The entry point extension can be, for example, but is not limited to, 0.05%, 0.1%, or 0.3%.

[0050] In some optional embodiments, cleaning is also included between the third annealing and the bending and straightening. The specific operation method is not limited and any method known to those skilled in the art can be used.

[0051] Secondly, the present invention provides the application of the above-mentioned heat-resistant oxygen-free copper strip in the preparation of ceramic copper-clad laminates for IGBT modules.

[0052] The heat-resistant oxygen-free copper strip provided by this invention has a conductivity ≥98% IACS, an oxygen content ≤20ppm, a hardness ≥100HV, a grain size ≤0.07mm after holding at 900℃ for 30min, and a grain size ≤0.08mm after holding at 1065℃ for 3min. It can meet the needs of IGBT development in fields such as high-power industrial frequency converters, welding machines, new energy vehicles (motor controllers, vehicle air conditioners, charging piles), rail transit equipment, white goods, photovoltaics, and wind power. It can also solve the problem of easy failure in welding oxygen-free copper to ceramic in IGBT module ceramic copper-clad laminates.

[0053] The present invention will be further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for the purpose of more detailed illustration and should not be construed as limiting the present invention in any way.

[0054] Example 1:

[0055] Melting and casting: Raw materials are weighed according to the alloy composition ratio, and then melted and cast sequentially. Before melting, the raw materials need to be cleaned and dried; after being added to the melting furnace, a vacuum of 1.8 × 10⁻⁶ is first applied. -2 Pa, then heat up to melt copper; after the copper plate is completely melted, heat to 1180℃, hold for 40 min, then introduce argon gas, then add 0.01% silver and 0.01% lanthanum by mass, let stand for 20 min; finally start casting at 1170℃ and casting speed of 70 mm / min.

[0056] Hot rolling: The ingot is heated in a walking beam furnace with a temperature range of 850℃, an initial rolling temperature of 750℃, a final rolling temperature of 500℃, and a total processing rate of 85%. After hot rolling, the ingot is water-cooled and then milled.

[0057] First cold rolling: The milled oxygen-free copper sheet is cold rolled in 7 passes, with a single pass processing rate of 15-35% and a total processing rate of 75%.

[0058] First annealing: The oxygen-free copper sheet after the first cold rolling is rolled into a coil and placed in a bell jar annealing furnace for recrystallization annealing. The annealing temperature is 500℃ and the holding time is 3h. After the first annealing is completed, it is cleaned.

[0059] Second cold rolling: The cleaned oxygen-free copper strip is subjected to a second cold rolling process, with 7 passes, a single pass processing rate of 20-25%, and a total processing rate of 80%.

[0060] Second annealing: The oxygen-free copper strip after the second cold rolling is placed in a bell jar annealing furnace for recrystallization annealing at a temperature of 500℃ for 2 hours; after the second annealing, it is cleaned.

[0061] Third cold rolling: 2 passes, with a single pass processing rate of 10-20% and a total processing rate of 35%; cleaning is carried out after the third cold rolling is completed.

[0062] Bending and straightening, unwinding tension 25 N / mm 2 Winding tension 40 N / mm 2 The entrance extends by 0.15%.

[0063] Example 2:

[0064] Melting and casting: Raw materials are weighed according to the alloy composition ratio, and then melted and cast sequentially. Before melting, the raw materials need to be cleaned and dried; after being added to the melting furnace, a vacuum of 1.2 × 10⁻⁶ is first applied. -2 Pa, then heat up to melt copper; after the copper plate is completely melted, heat to 1150℃, hold for 60 min, then introduce argon gas, then add 0.001% silver and 0.001% lanthanum by mass, let stand for 5 min; finally start casting at 1150℃ and 100 mm / min.

[0065] Hot rolling: The ingot is heated in a walking beam furnace with a temperature range of 800℃, an initial rolling temperature of 700℃, a final rolling temperature of 400℃, and a total processing rate of 70%. After hot rolling, the ingot is water-cooled and then milled.

[0066] First cold rolling: The milled oxygen-free copper sheet is cold rolled in 9 passes, with a single pass processing rate of 15-40% and a total processing rate of 90%.

[0067] First annealing: The oxygen-free copper sheet after the first cold rolling is rolled into a coil and placed in a bell jar annealing furnace for recrystallization annealing. The annealing temperature is 600℃ and the holding time is 0.5h. After the first annealing is completed, it is cleaned.

[0068] Second cold rolling: The cleaned oxygen-free copper strip is subjected to a second cold rolling process, with 5 passes, a single pass processing rate of 20-35%, and a total processing rate of 70%.

[0069] Second annealing: The oxygen-free copper strip after the second cold rolling is placed in a bell jar annealing furnace for recrystallization annealing at a temperature of 450℃ for 6 hours; after the second annealing, it is cleaned.

[0070] Third cold rolling: 2 passes, with a single pass processing rate of 10-25% and a total processing rate of 30%; cleaning is carried out after the third cold rolling is completed.

[0071] Bending and straightening, unwinding tension 45 N / mm 2 Winding tension 60 N / mm 2 The entrance extends by 0.3%.

[0072] Example 3:

[0073] Melting and casting: Weigh the raw materials according to the alloy composition ratio, and then proceed with melting and casting sequentially. Before melting, the raw materials need to be cleaned and dried; after being added to the melting furnace, a vacuum of 1.5 × 10⁻⁶ is first applied. -2 Pa, then heat up to melt copper; after the copper plate is completely melted, heat to 1200℃, hold for 20 min, then introduce argon gas, then add 0.1% silver and 0.1% lanthanum by mass, let stand for 10 min; finally start casting, casting temperature 1190℃, casting speed 50 mm / min.

[0074] Hot rolling: The ingot is heated in a walking beam furnace with a temperature range of 900℃, an initial rolling temperature of 800℃, a final rolling temperature of 600℃, and a total processing rate of 95%. After hot rolling, the ingot is water-cooled and then milled.

[0075] First cold rolling: The milled oxygen-free copper sheet is cold rolled in 5 passes, with a single pass processing rate of 15-30% and a total processing rate of 60%.

[0076] First annealing: The oxygen-free copper sheet after the first cold rolling is rolled into a coil and placed in a bell jar annealing furnace for recrystallization annealing. The annealing temperature is 400℃ and the holding time is 12h. After the first annealing is completed, it is cleaned.

[0077] Second cold rolling: The cleaned oxygen-free copper strip is subjected to a second cold rolling process, with 9 passes, a single pass processing rate of 20-30%, and a total processing rate of 85%.

[0078] Second annealing: The oxygen-free copper strip after the second cold rolling is placed in a bell jar annealing furnace for recrystallization annealing at a temperature of 550℃ and a holding time of 0.5h; after the second annealing, it is cleaned.

[0079] Third cold rolling: 3 processing passes, with a single pass processing rate of 10-20% and a total processing rate of 45%; cleaning is carried out after the third cold rolling is completed.

[0080] Bending and straightening, unwinding tension 10N / mm 2 Winding tension 18 N / mm 2 The entrance extends by 0.05%.

[0081] Comparative Example 1:

[0082] The difference from Example 1 is that silver and lanthanum are not added.

[0083] Comparative Example 2:

[0084] The difference from Example 1 is that the mass fraction of silver is 0.11% and the mass fraction of lanthanum is 0.11%.

[0085] Comparative Example 3:

[0086] The difference from Example 1 is that the final rolling temperature of the hot rolling is 620°C.

[0087] Comparative Example 4:

[0088] The difference from Example 1 is that the final rolling temperature of the hot rolling is 380°C.

[0089] Comparative Example 5:

[0090] The difference from Example 1 is that there is no first annealing.

[0091] Comparative Example 6:

[0092] The difference from Example 1 is that the second annealing temperature is 600°C and the time is 1 hour.

[0093] Comparative Example 7:

[0094] The difference from Example 1 is that the second annealing temperature is 400°C and the time is 6 hours.

[0095] Comparative Example 8:

[0096] The difference from Example 1 is that there is no second annealing.

[0097] Comparative Example 9:

[0098] The difference from Example 1 is that the total processing rate of the third cold rolling is 25%.

[0099] Table 1 Performance and organizational structure of the examples and comparative examples

[0100]

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat-resistant oxygen-free copper strip, characterized in that, By mass percentage, it includes: Ag 0.001%~0.1%, La 0.001%~0.1%, with the balance being Cu; The preparation method of the heat-resistant oxygen-free copper strip includes the following steps: The ingredients are proportioned according to mass percentage, and then smelting, casting, hot rolling, first cold rolling, first annealing, second cold rolling, second annealing and third cold rolling are carried out in sequence to prepare heat-resistant oxygen-free copper strip. The hot rolling includes: heating the cast ingot to 800~900℃ and then hot rolling it, wherein the initial rolling temperature is 700~800℃ and the final rolling temperature is 400~600℃. The temperature of the first annealing is 400~600℃, and the holding time is 0.5~12h; The second annealing temperature is 450~550℃, and the holding time is 0.5~6h; The first cold rolling process consists of 5 to 9 passes, with a single pass processing rate of 15% to 40% and a total processing rate of 60% to 90%. The second cold rolling process consists of 5 to 9 passes, with a single pass processing rate of 20% to 35% and a total processing rate of 70% to 85%. The third cold rolling process consists of 2 to 3 passes, with a single pass processing rate of 10% to 25% and a total processing rate of 30%, 35%, or 45%.

2. The heat-resistant oxygen-free copper strip according to claim 1, characterized in that, The melting temperature is 1150~1200℃.

3. The heat-resistant oxygen-free copper strip according to claim 1, characterized in that, The casting temperature is 1150~1190℃, and the casting speed is 50~100mm / min.

4. The heat-resistant oxygen-free copper strip according to claim 1, characterized in that, The total processing rate of the hot rolling is 70% to 95%.

5. The heat-resistant oxygen-free copper strip according to claim 1, characterized in that, The process after hot rolling also includes milling.

6. The heat-resistant oxygen-free copper strip according to claim 1, characterized in that, The third cold rolling process also includes tension straightening; The process parameters for the bending straightening include: unwinding tension of 10~45 N / mm. 2 The winding tension is 18~60 N / mm. 2 The entry point ranges from 0.05% to 0.3%.

7. The application of the heat-resistant oxygen-free copper strip according to any one of claims 1 to 6 in the preparation of ceramic copper-clad laminates for IGBT modules.

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