High-strength and high-conductivity Cu-Fe alloy strip for etching as well as preparation method and application of high-strength and high-conductivity Cu-Fe alloy strip

Abstract

The invention discloses a high-strength and high-conductivity Cu-Fe alloy strip for etching as well as a preparation method and application thereof, the Cu-Fe alloy strip comprises the following components in percentage by weight: 2.1%-2.6% of Fe, 0.015%-0.15% of P, 0.100%-0.160% of Zn and the balance of Cu and inevitable impurities, and the total amount of the impurities is less than or equal to 0.5%; the preparation method comprises the steps of vacuum melting, homogenization treatment, hot rolling, cold rolling, intermediate annealing, final cold rolling and stress relief annealing. The tensile strength of the obtained Cu-Fe alloy strip is larger than or equal to 580 MPa, the electric conductivity is larger than or equal to 65% IACS, the warping degree after etching is smaller than or equal to 0.05 mm / 300 mm, and the Cu-Fe alloy strip can be applied to integrated circuit lead frames, fine metal mask plates, connectors and flexible circuit boards; the Cu-Fe alloy strip prepared through the method is high in strength, high in conductivity and excellent in isotropic etching performance, and the harsh requirements of high-end electronic components for the comprehensive performance of materials can be met.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal processing technology, specifically to a high-strength, high-conductivity Cu-Fe alloy strip for etching, its preparation method, and its application. Background Technology

[0002] Cu-Fe alloys, due to their combination of good strength, conductivity, and low cost, have broad application prospects in the electronics and electrical fields, particularly in components requiring precision etching such as lead frames and metal masks. These components demand materials that not only possess high strength to support and fix the chip, but also high conductivity to ensure signal transmission efficiency. Crucially, the materials must also have good plate shape, highly uniform microstructure, and chemical composition to achieve isotropic precision etching and obtain patterns with vertical and smooth sidewalls.

[0003] However, existing Cu-Fe alloys, when applied to integrated circuit lead frames, fine metal masks, and especially components requiring precision chemical etching, suffer from problems such as uneven internal stress distribution and directional microstructure (e.g., banded structure) due to improper rolling processes. These issues lead to severe localized stress release during etching due to anisotropic corrosion, resulting in uncontrollable warping deformation (typically much greater than 10 mm / 300 mm). Furthermore, the etched patterns exhibit non-perpendicular sidewalls and serrations, significantly impacting product accuracy and yield. Therefore, developing a Cu-Fe alloy material with good shape and surface finish, uniform microstructure, excellent etching performance, and simultaneously high strength and high conductivity, along with its preparation method, has become a pressing technical problem in this field. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of uneven internal stress distribution and directional microstructure caused by improper rolling process in existing Cu-Fe alloy strips. These problems lead to severe local stress release due to anisotropic corrosion during etching, resulting in uncontrollable warping deformation of the product. Furthermore, the sidewalls of the etched pattern are not perpendicular and have serrations, which seriously affect the product accuracy and yield. This invention provides a method for preparing high-strength and high-conductivity Cu-Fe alloy strips for etching and its application.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides a high-strength, high-conductivity Cu-Fe alloy strip for etching. By weight percentage, the composition of the Cu-Fe alloy strip is: Fe 2.1%-2.6%, P 0.015%-0.15%, Zn 0.100%-0.160%, with the balance being Cu and unavoidable impurities, and the total amount of impurities ≤0.5%.

[0006] Preferably, the composition of the Cu-Fe alloy strip in this invention is: Fe 2.2%-2.4%, P 0.020%-0.040%, Zn 0.100%-0.160%, with the balance being Cu and unavoidable impurities, and the total amount of impurities ≤0.5%.

[0007] Preferably, the Cu-Fe alloy strip of the present invention has a tensile strength ≥580 MPa, a conductivity ≥65% IACS, and a warpage after etching ≤0.05 mm / 300 mm.

[0008] This invention also provides a method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching, comprising the following steps: S1 Vacuum casting: The prepared Cu-Fe alloy composition is placed in a vacuum induction furnace for melting, and then cast into a mold to obtain an alloy ingot; S2 Homogenization Heat Treatment: The obtained alloy ingot is subjected to homogenization heat treatment; S3 Hot Rolling and Solution Treatment: The alloy ingot after homogenization heat treatment is directly hot rolled, and the strip is quenched at the same time. S4 Cold Rolling and Intermediate Annealing: Thick strips that have been hot-rolled and quenched are subjected to multiple cold rolling passes, and one or more intermediate annealing processes are carried out during the cold rolling process. S5 final cold rolling: The alloy strip after intermediate annealing is cold rolled out to further improve the material's performance and flatness; S6 Stress-Relief Annealing: To eliminate the internal stress generated in the strip after rolling, the strip is subjected to stress-relief annealing treatment, which yields a high-strength, high-conductivity Cu-Fe alloy strip with good plate shape for etching.

[0009] Furthermore, in step S2 of this invention, the homogenization heat treatment temperature is 970-1010 ℃ and the time is 4.5-5.5 h.

[0010] Furthermore, in step S3 of this invention, the hot rolling temperature is 900-940 ℃, the total deformation is 85%-90%, the quenching temperature is 750-770 ℃, and rapid water cooling is performed.

[0011] Furthermore, in step S4 of this invention, the total deformation of the multi-pass cold rolling is 90%-98.5%; the intermediate annealing temperature is 450℃-600℃, the holding time is 7-8 h, and the annealing rate is 34-54 m / min.

[0012] Furthermore, the total deformation of the cold rolling process in step S5 of this invention is 17.8%.

[0013] Furthermore, in step S6 of this invention, the strip rolled to the finished thickness is subjected to stress-relief annealing at a temperature of 450 ℃ and an annealing rate of 26-28 m / min.

[0014] This invention also provides an application of a high-strength, high-conductivity Cu-Fe alloy strip for etching in integrated circuit lead frames, fine metal masks, connectors, and flexible circuit boards. Utilizing the high strength, high conductivity, and excellent isotropic etching performance of the Cu-Fe alloy strip of this invention, the stringent requirements for comprehensive material performance in high-end electronic components can be met.

[0015] Compared with the prior art, the present invention has the following advantages: (1) This invention uses a synergistic process of "solution + cold rolling + aging" to control the precipitation of Fe elements in the Cu matrix in the form of fine, dispersed particles, which greatly eliminates the segregation of micro-components. This uniform microstructure ensures that the etchant erosion rate of the material remains consistent in all directions, thereby achieving isotropic etching and obtaining high-precision patterns with vertical sidewalls, smooth surfaces, and no serrations. The invention uses multi-pass cold rolling with a low processing rate to break and avoid the formation of banded structures, intermediate annealing to fully recrystallize and homogenize the structure, and final stress-relief annealing to actively eliminate the macroscopic internal stress that causes etching warping; (2) The present invention utilizes the ability of nanoscale or submicron-scale Fe-rich precipitates to effectively pin dislocations and improve material strength. At the same time, its scattering effect on electrons is relatively weak. Therefore, the material can maintain high conductivity (≥65% IACS) while obtaining high strength (≥580 MPa). (3) By introducing a multi-pass cold rolling and intermediate annealing process, this invention helps to further refine the grains and promote the uniform distribution of precipitates, avoiding the banded distribution of the microstructure that may be caused by cold rolling with large deformation in one direction, thereby improving the etching uniformity. (4) The present invention uses multiple passes of low-processing-rate rolling and heat treatment to make the strip have a good shape and a smooth strip surface, reduce the degree of strip warping after etching, and improve product yield. (5) The preparation method provided by the present invention has a clear process flow, clear process parameters, is easy to realize industrial production, and the product quality is stable. Attached Figure Description

[0016] Figure 1 This is an optical microscope image of the Cu-Fe alloy strip after stress-relief annealing in Embodiment 1 of the present invention; Figure 2 (a) is a diagram of the Cu-Fe alloy strip prepared in Example 1 of the present invention after etching when used to fabricate an integrated circuit lead frame; Figure 2(b) is a finished product image of the Cu-Fe alloy strip prepared in Example 1 of the present invention after etching to make an integrated circuit lead frame. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments, so as to facilitate a clearer understanding of the present invention, but these embodiments do not constitute a limitation on the present invention. Example 1

[0018] This embodiment describes a method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching, comprising the following steps: S1 Vacuum Casting: A Cu-Fe alloy is prepared using electrolytic copper and pure iron. The electrolytic copper is melted in a vacuum induction furnace and covered with charcoal at a melting temperature of 1280 ℃. After the electrolytic copper has melted, pure iron is added to the furnace at a temperature ≥1200 ℃ and held for 15 min. The mixture is then cast in a graphite mold at a casting temperature of 1180-1210 ℃ to obtain a Cu-Fe alloy ingot. The Cu-Fe alloy ingot composition is as follows: Fe 2.21 wt%, P 0.031 wt%, Zn 0.107 wt%, with the balance being Cu and unavoidable impurities. S2 Homogenization Heat Treatment: The Cu-Fe alloy ingot is placed in a walking beam furnace for high-temperature homogenization heat treatment at a temperature of 970-1010 ℃ for 5 h. S3 Hot Rolling and Solution Treatment: The homogenized and heat-annealed Cu-Fe alloy ingot is placed in a hot rolling mill for hot rolling at a temperature of 924 ℃ and a total deformation of 90%. The resulting hot-rolled billet is then subjected to water quenching and solution annealing at a temperature of 768 ℃ and then further processed by double-sided milling. S4 Cold Rolling and Intermediate Annealing: The strip undergoes deformation heat treatment with a total deformation of 98.5%. First, it undergoes four passes of cold rolling on a roughing mill. When the deformation reaches 91%, it undergoes the first intermediate annealing (550 ℃ / 7 h). After annealing, it passes through a cleaning line and then undergoes five passes of cold rolling on a finishing mill. When the deformation reaches 96.2%, the strip undergoes a second intermediate annealing (450 ℃ / 8 h). The annealed alloy strip continues to undergo one pass of low-rate cold rolling on the finishing mill. When the deformation reaches 97.5%, it undergoes a third intermediate annealing in an air-cushion furnace (600 ℃, annealing rate 34 m / min). Finally, it undergoes one pass of low-rate rolling on the finishing mill. When the deformation reaches 98.1%, it undergoes a fourth intermediate annealing (600 ℃, annealing rate 43 m / min). After annealing, a final cold rolling process is performed with a bottom retention, resulting in a deformation of 98.5%. The material is then subjected to bottom retention annealing in an air cushion furnace (600 °C, annealing rate of 54 m / min). S5 Final Cold Rolling: Final cold rolling is performed in one pass on a finishing mill, with a total deformation of 17.8%, to obtain a Cu-Fe alloy strip with a thickness of 0.203 mm; S6 Stress-relief annealing treatment: In order to eliminate the internal stress generated in the Cu-Fe alloy strip after rolling, the Cu-Fe alloy strip is subjected to stress-relief annealing treatment. The Cu-Fe alloy strip is annealed slowly at low temperature in an air cushion furnace to eliminate the internal stress of the strip. The annealing temperature is 450 ℃ and the annealing rate is 26 m / min, thus obtaining the high-strength and high-conductivity Cu-Fe alloy strip for etching in this embodiment.

[0019] In this embodiment, after deformation heat treatment, the Fe-rich phase precipitates in the form of nanoparticles in the Cu-Fe alloy strip. The material after stress-relief annealing was tested; see attached figure. Figure 1 ,from Figure 1 As can be seen, the alloy microstructure remains uniform, and the precipitated phases do not undergo significant coarsening. The excellent mechanical properties of the Cu-Fe alloy strip obtained by this invention are attributed to the strengthening effect of the dispersed precipitates; the high electrical conductivity of the Cu-Fe alloy strip is attributed to the full precipitation of Fe elements from the matrix, which reduces the scattering of electrons by solid solution atoms; and its excellent etching performance is attributed to the uniform microstructure.

[0020] Application Example 1 The Cu-Fe alloy strip prepared in Example 1 was used to fabricate an integrated circuit lead frame. After etching, the strip warpage reached 0.05 mm / 300 mm. Figure 2 As shown in (a), the strip exhibits good flatness after stress-relief annealing, with almost no warping after etching, and the finished product after etching is as follows: Figure 2 As shown in (b). Example 2

[0021] This embodiment describes a method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching, comprising the following steps: S1 Vacuum Casting: A Cu-Fe alloy is prepared using electrolytic copper and pure iron. The electrolytic copper is melted in a vacuum induction furnace and covered with charcoal at a melting temperature of 1300 ℃. After the electrolytic copper has melted, pure iron is added to the furnace at a temperature ≥1200 ℃ and held for 15 min. The mixture is then cast in a graphite mold at a casting temperature of 1180-1210 ℃ to obtain a Cu-Fe alloy ingot. The mass percentage composition of the obtained Cu-Fe alloy ingot is: Fe 2.50%, P 0.14%, Zn 0.156%, with the balance being Cu and unavoidable impurities. S2 Homogenization Heat Treatment: The Cu-Fe alloy ingot is placed in a walking beam furnace for high-temperature homogenization heat treatment at a temperature of 970-1010 ℃ for 5.5 h. S3 Hot Rolling and Solution Treatment: The homogenized and heat-annealed Cu-Fe alloy ingot is placed in a hot rolling mill for hot rolling at a temperature of 940 ℃ and a total deformation of 88%. The resulting hot-rolled billet is then water-quenched at a temperature of 750 ℃ ​​and solution-annealed before being further processed in a double-sided mill. S4 Cold Rolling and Intermediate Annealing: The strip undergoes deformation heat treatment with a total deformation of 98.5%. First, it undergoes four passes of cold rolling on a roughing mill. When the deformation reaches 90%, it undergoes the first intermediate annealing (550 ℃ / 7 h). After annealing, it passes through a cleaning line and then undergoes five passes of cold rolling on a finishing mill. When the deformation reaches 95%, the strip undergoes a second intermediate annealing (450 ℃ / 8 h). The annealed alloy strip continues to undergo one pass of low-rate cold rolling on the finishing mill. When the deformation reaches 97.5%, it undergoes a third intermediate annealing in an air-cushion furnace (600 ℃, annealing rate 34 m / min). Finally, it undergoes one pass of low-rate rolling on the finishing mill. When the deformation reaches 98.1%, it undergoes a fourth intermediate annealing (600 ℃, annealing rate 43 m / min). After annealing, a final cold rolling process is performed with a bottom retention, resulting in a deformation of 98.5%. The material is then subjected to bottom retention annealing in an air cushion furnace (600 °C, annealing rate of 54 m / min). S5 Final Cold Rolling: Final cold rolling is performed in one pass on a finishing mill, with a total deformation of 17.8%, to obtain a Cu-Fe alloy strip with a thickness of 0.206 mm; S6 Stress-relief annealing treatment: In order to eliminate the internal stress generated in the Cu-Fe alloy strip after rolling, the Cu-Fe alloy strip is subjected to stress-relief annealing treatment. The Cu-Fe alloy strip is annealed slowly at low temperature in an air cushion furnace to eliminate the internal stress of the strip. The annealing temperature is 450 ℃ and the annealing rate is 28 m / min, thus obtaining the high-strength and high-conductivity Cu-Fe alloy strip for etching in this embodiment. Example 3

[0022] This embodiment describes a method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching, comprising the following steps: S1 Vacuum Casting: A Cu-Fe alloy is prepared using electrolytic copper and pure iron. The electrolytic copper is melted in a vacuum induction furnace and covered with charcoal at a melting temperature of 1300 ℃. After the electrolytic copper has melted, pure iron is added to the furnace at a temperature ≥1200 ℃ and held for 15 min. The mixture is then cast in a graphite mold at a casting temperature of 1180-1210 ℃ to obtain a Cu-Fe alloy ingot. The mass percentage composition of the obtained Cu-Fe alloy ingot is: Fe 2.56%, P 0.147%, Zn 0.132%, with the balance being Cu and unavoidable impurities. S2 Homogenization Heat Treatment: The Cu-Fe alloy ingot is placed in a walking beam furnace for high-temperature homogenization heat treatment at a temperature of 970-1010 ℃ for 4.5 h. S3 Hot Rolling and Solution Treatment: The homogenized and heat-annealed Cu-Fe alloy ingot is placed in a hot rolling mill for hot rolling at a temperature of 900 ℃ and a total deformation of 85%. The resulting hot-rolled billet is then water-quenched at a temperature of 750 ℃ ​​and solution-annealed before being further processed in a double-sided mill. S4 Cold Rolling and Intermediate Annealing: The strip undergoes deformation heat treatment with a total deformation of 94.5%. First, it undergoes four passes of cold rolling on a roughing mill. When the deformation reaches 90%, it undergoes the first intermediate annealing (550 ℃ / 7 h). After annealing, it passes through a cleaning line and then undergoes five passes of cold rolling on a finishing mill. When the deformation reaches 92%, the strip undergoes a second intermediate annealing (450 ℃ / 8 h). The annealed alloy strip continues to undergo one pass of low-rate cold rolling on the finishing mill. When the deformation reaches 93.5%, it undergoes a third intermediate annealing in an air-cushion furnace (600 ℃, annealing rate 34 m / min). Finally, it undergoes one pass of low-rate rolling on the finishing mill. When the deformation reaches 94.5%, it undergoes a fourth intermediate annealing (600 ℃, annealing rate 43 m / min). After annealing, a final cold rolling process is performed with a bottom retention, resulting in a deformation of 94.5%. The material is then subjected to bottom retention annealing in an air cushion furnace (600 °C, annealing rate of 54 m / min). S5 Final Cold Rolling: Final cold rolling is performed in one pass on a finishing mill, with a total deformation of 17.8%, to obtain a Cu-Fe alloy strip with a thickness of 0.205 mm; S6 Stress-relief annealing treatment: In order to eliminate the internal stress generated in the Cu-Fe alloy strip after rolling, the Cu-Fe alloy strip is subjected to stress-relief annealing treatment. The Cu-Fe alloy strip is annealed slowly at low temperature in an air cushion furnace to eliminate the internal stress of the strip. The annealing temperature is 450 ℃ and the annealing rate is 26 m / min, thus obtaining the high-strength and high-conductivity Cu-Fe alloy strip for etching in this embodiment.

[0023] Comparative Example 1 This embodiment describes a method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching, comprising the following steps: S1 Vacuum Casting: A Cu-Fe alloy is prepared using electrolytic copper and pure iron. The electrolytic copper is melted in a vacuum induction furnace and covered with charcoal at a melting temperature of 1280 ℃. After the electrolytic copper has melted, pure iron is added to the furnace at a temperature ≥1200 ℃ and held for 15 min. The mixture is then cast in a graphite mold at a casting temperature of 1180-1210 ℃ to obtain a Cu-Fe alloy ingot. The Cu-Fe alloy ingot composition is as follows: Fe 2.21 wt%, P 0.031 wt%, Zn 0.107 wt%, with the balance being Cu and unavoidable impurities. S2 Homogenization Heat Treatment: The Cu-Fe alloy ingot is placed in a walking beam furnace for high-temperature homogenization heat treatment at 970-1010 ℃ for 5 h. S3 Hot Rolling and Solution Treatment: The homogenized and heat-annealed Cu-Fe alloy ingot is placed in a hot rolling mill for hot rolling at a temperature of 924 ℃ and a total deformation of 90%. The resulting hot-rolled billet is then water-quenched at a temperature of 768 ℃ and solution-annealed before being further processed in a double-sided mill. S4 Cold Rolling and Intermediate Annealing: The strip undergoes deformation heat treatment with a total deformation of 98.1%. First, it undergoes two passes of cold rolling on a roughing mill. When the deformation reaches 91%, it undergoes the first intermediate annealing (550 ℃ / 7 h). After annealing, it passes through a cleaning line and then undergoes five passes of cold rolling on a finishing mill. When the deformation reaches 96.2%, the strip undergoes a second intermediate annealing (450 ℃ / 8 h). The annealed alloy strip continues to undergo two passes of cold rolling on the finishing mill. After the deformation reaches 98.1%, it undergoes a third intermediate annealing in an air-cushion furnace (600 ℃, annealing rate 34 m / min). S5 Final Cold Rolling: Final cold rolling is performed in one pass on a finishing mill, with a total deformation of 31.3%, resulting in a Cu-Fe alloy strip with a thickness of 0.203 mm; S6 Stress-relief annealing treatment: In order to eliminate the internal stress generated in the Cu-Fe alloy strip after rolling, the Cu-Fe alloy strip is subjected to stress-relief annealing treatment. The Cu-Fe alloy strip is annealed slowly at low temperature in an air cushion furnace to eliminate the internal stress of the strip. The annealing temperature is 450 ℃ and the annealing rate is 26 m / min, thus obtaining the high-strength and high-conductivity Cu-Fe alloy strip for etching in this embodiment.

[0024] This comparative example shows that by changing the number of cold rolling and intermediate annealing processes, the flatness of the sheet is poor, and the large deformation cold rolling may result in a banded distribution of the microstructure.

[0025] Comparative Application Example 1 The Cu-Fe alloy strip prepared in Comparative Example 1 was used to fabricate integrated circuit lead frames. After etching, the strip warped significantly, resulting in the lead pitch accuracy after etching not meeting the requirements of end-use applications.

[0026] Comparative Example 2 This embodiment describes a method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching, comprising the following steps: S1 Vacuum Casting: A Cu-Fe alloy is prepared using electrolytic copper and pure iron. The electrolytic copper is melted in a vacuum induction furnace and covered with charcoal at a melting temperature of 1280 ℃. After the electrolytic copper has melted, pure iron is added to the furnace at a temperature ≥1200 ℃ and held for 15 min. The mixture is then cast in a graphite mold at a casting temperature of 1180-1210 ℃ to obtain a Cu-Fe alloy ingot. The Cu-Fe alloy ingot composition is as follows: Fe 2.21 wt%, P 0.031 wt%, Zn 0.107 wt%, with the balance being Cu and unavoidable impurities. S2 Homogenization Heat Treatment: The Cu-Fe alloy ingot is placed in a walking beam furnace for high-temperature homogenization heat treatment at a temperature of 970-1010 ℃ for 5 h. S3 Hot Rolling and Solution Treatment: The homogenized and heat-annealed Cu-Fe alloy ingot is placed in a hot rolling mill for hot rolling at a temperature of 924 ℃ and a total deformation of 90%. The resulting hot-rolled billet is then water-quenched at a temperature of 768 ℃ and solution-annealed before being further processed in a double-sided mill. S4 Cold Rolling and Intermediate Annealing: The strip undergoes deformation heat treatment with a total deformation of 98.5%. First, it undergoes four passes of cold rolling on a roughing mill. When the deformation reaches 91%, it undergoes the first intermediate annealing (550 ℃ / 7 h). After annealing, it passes through a cleaning line and then undergoes five passes of cold rolling on a finishing mill. When the deformation reaches 96.2%, the strip undergoes a second intermediate annealing (450 ℃ / 8 h). The annealed alloy strip continues to undergo one pass of low-rate cold rolling on the finishing mill. When the deformation reaches 97.5%, it undergoes a third intermediate annealing in an air-cushion furnace (600 ℃, annealing rate 34 m / min). Finally, it undergoes one pass of low-rate rolling on the finishing mill. When the deformation reaches 98.1%, it undergoes a fourth intermediate annealing (600 ℃, annealing rate 43 m / min). After annealing, a final cold rolling process is performed with a bottom retention, resulting in a deformation of 98.5%. The material is then subjected to bottom retention annealing in an air cushion furnace (600 °C, annealing rate of 54 m / min). S5 Final Cold Rolling: Final cold rolling is performed in one pass on a finishing mill, with a total deformation of 17.8%, to obtain a Cu-Fe alloy strip with a thickness of 0.203 mm; S6 Stress-relief annealing treatment: In order to eliminate the internal stress generated in the Cu-Fe alloy strip after rolling, the Cu-Fe alloy strip is subjected to stress-relief annealing treatment. The Cu-Fe alloy strip is annealed slowly at low temperature in an air cushion furnace to eliminate the internal stress of the strip. The annealing temperature is 450 ℃ and the annealing rate is 35 m / min, thus obtaining the high-strength and high-conductivity Cu-Fe alloy strip for etching in this embodiment.

[0027] This comparative example shows that by accelerating the stress-relief annealing process, insufficient stress relief resulted in severe warping of the sheet material and a reduced product yield.

[0028] Comparative Application Example 2 The Cu-Fe alloy strip prepared in Comparative Example 2 was used to fabricate integrated circuit lead frames. After etching, the strip warped to 12 mm / 300 mm.

[0029] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0030] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high-strength, high-conductivity Cu-Fe alloy strip for etching, characterized in that: The composition of the Cu-Fe alloy strip by weight percentage is: Fe 2.1%-2.6%, P 0.015%-0.15%, Zn 0.100%-0.160%, with the balance being Cu and unavoidable impurities, and the total amount of impurities ≤0.5%.

2. The high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 1, characterized in that: The composition of the Cu-Fe alloy strip by weight percentage is: Fe 2.2%-2.4%, P 0.020%-0.040%, Zn 0.100%-0.160%, with the balance being Cu and unavoidable impurities, and the total amount of impurities ≤0.5%.

3. The high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 1, characterized in that: The Cu-Fe alloy strip has a tensile strength ≥580 MPa, a conductivity ≥65% IACS, and a warpage after etching ≤0.05 mm / 300 mm.

4. A method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching according to any one of claims 1-3, characterized in that, Includes the following steps: S1 Vacuum casting: The prepared Cu-Fe alloy composition is placed in a vacuum induction furnace for melting, and then cast into a mold to obtain an alloy ingot; S2 Homogenization Heat Treatment: The obtained alloy ingot is subjected to homogenization heat treatment; S3 Hot Rolling and Solution Treatment: The alloy ingot after homogenization heat treatment is directly hot rolled, and the strip is quenched at the same time. S4 cold rolling and intermediate annealing: The thick strip after hot rolling and quenching is subjected to multiple cold rolling passes, and one or more intermediate annealing processes are carried out during the cold rolling process. S5 final cold rolling: The alloy strip after intermediate annealing is cold rolled out to further improve the material's performance and flatness; S6 Stress-Relief Annealing: To eliminate the internal stress generated in the strip after rolling, the strip is subjected to stress-relief annealing treatment, which yields a high-strength, high-conductivity Cu-Fe alloy strip with good plate shape for etching.

5. A method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 4, characterized in that: In step S2, the homogenization heat treatment temperature is 970-1010 ℃, and the time is 4.5-5.5 h.

6. The method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 4, characterized in that: In step S3, the hot rolling temperature is 900-940 ℃, the total deformation is 85%-90%, the quenching temperature is 750-770 ℃, and rapid water cooling is performed.

7. The method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 4, characterized in that: In step S4, the total deformation of the multi-pass cold rolling is 90%-98.5%; the intermediate annealing temperature is 450℃-600℃, the holding time is 7-8 h, and the annealing rate is 34-54 m / min.

8. The method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 4, characterized in that: The total deformation in the cold rolling process in step S5 is 17.8%.

9. A method for preparing a high-strength, high-conductivity Cu-Fe alloy strip for etching according to claim 3, characterized in that: In step S6, the strip rolled to the finished thickness is subjected to stress-relief annealing at a temperature of 450 ℃ and an annealing rate of 26-28 m / min.

10. The application of a high-strength, high-conductivity Cu-Fe alloy strip for etching as described in any one of claims 1-3 in integrated circuit lead frames, fine metal masks, connectors, and flexible circuit boards.

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