CN114525461B

CN114525461B - Method for preparing fine-grain KFC strip and fine-grain KFC strip

Info

Publication number: CN114525461B
Application number: CN202210062224.XA
Authority: CN
Inventors: 赵久辉; 郭祊鹤; 陈岩; 肖桥平; 周涛; 刘昆
Original assignee: Jiangxi Copper Technology Research Institute Co ltd
Current assignee: Jiangxi Copper Technology Research Institute Co ltd
Priority date: 2022-01-19
Filing date: 2022-01-19
Publication date: 2023-03-14
Anticipated expiration: 2042-01-19
Also published as: CN114525461A

Abstract

The invention belongs to the field of copper alloy strip processing technology, and particularly relates to a method for preparing a fine-grain KFC strip, which comprises the following steps: preparing a KFC cast rod, and continuously extruding the KFC cast rod to obtain an extruded plate blank; carrying out aging treatment on the obtained extruded plate blank to obtain an aging plate blank; carrying out multi-pass cold rolling on the obtained aging plate blank to obtain a strip, and then annealing; and (3) carrying out cold finish rolling on the annealed strip, cleaning, slitting and packaging to obtain the fine-grained KFC strip with the thickness of 0.1-1.5 mm. The average grain size of the obtained KFC alloy strip is less than or equal to 10 mu m, the tensile strength can reach 420 to 470MPa, the elongation is 5 to 15 percent, the Vickers hardness is 120 to 135, the electric conductivity is more than or equal to 87 IACS, and the Vickers hardness is more than or equal to 115 after the KFC alloy strip is subjected to heat preservation for 3min at 470 ℃; the preparation method has short flow and can realize industrialized and large-scale batch stable production.

Description

Method for preparing fine-grain KFC strip and fine-grain KFC strip

Technical Field

The invention belongs to the technical field of processing of packaging materials of integrated circuits and semiconductor components, and particularly relates to a method for preparing a fine-grain KFC strip and the fine-grain KFC strip.

Background

At present, the lead frame material is used as a key material for packaging integrated circuits and semiconductor components, and is used for fixing chips in the integrated circuits, protecting internal components, transmitting electric signals and radiating element heat outwards. The most used lead frame material in the market is Cu-Fe-P series alloy, and KFC (C19210) alloy is a key material in the electronic information industry of integrated circuits, semiconductor discrete devices and the like due to excellent electrical conductivity, thermal conductivity, processing property, proper strength, platability, solderability, affinity with packaging materials, lower cost and the like. At present, the demand of lead frame materials is further increased due to rapid development of domestic and foreign electronic information industries, KFC strips are low in processing difficulty and strong in market competition, and in order to keep the continuous competitiveness of KFC lead frame materials in the market, product characteristics need to be improved through improved technology.

The preparation process of KFC copper alloy strip in the prior art mainly comprises 3 types.

The first KFC strip preparation process is semi-continuous casting → face milling → heating → hot rolling → rough rolling → annealing → medium rolling → annealing → finish rolling → washing, slitting and packaging. The first is the traditional KFC strip preparation process, which is also the mainstream production method in the market at present.

In order to save production cost, a hot rolling procedure is not adopted, and another two preparation processes of KFC strips appear. The second process is horizontal continuous casting → face milling → rough rolling → annealing → medium rolling → annealing → finish rolling → cleaning, slitting and packaging, the KFC alloy does not undergo high temperature deformation, the defects of air holes, inclusions and the like are difficult to eliminate, and the phenomena of edge cracking, peeling and the like are easy to occur in the subsequent deformation process, so that the yield is reduced.

The third process is up continuous casting → continuous extrusion → rough rolling → annealing → medium rolling → annealing → finish rolling → washing, slitting and packaging. In the third process, sufficient recrystallization occurs in the continuous extrusion process, a bell jar furnace is generally used for long-time heat preservation after cold rolling in order to ensure that a second phase is sufficiently separated out to improve the conductivity, the cold rolling provides a driving force for recrystallization and growth, and a grain structure can be remarkably grown after annealing.

Disclosure of Invention

The invention discloses a preparation method of a short-process KFC strip, which aims to solve any one of the problems and the potential problems in the prior art.

In order to solve the above problems, the technical solution of the present invention provides: a method of producing a fine-grained KFC strip, said method comprising the steps of:

s1) preparing a KFC cast rod,

s2) continuously extruding the KFC cast rods obtained in the S1) to obtain extruded slabs;

s3) carrying out aging treatment on the extruded plate blank obtained in the S2) to obtain an aged plate blank;

s4) carrying out multi-pass cold rolling on the aging plate blank obtained in the S3) to obtain a strip, and then annealing;

and S5) carrying out cold finish rolling on the strip annealed in the step S4), cleaning, slitting and packaging to obtain the fine-grain KFC strip (in the method, S1) to S5) need to be operated in sequence and cannot be adjusted back and forth).

Further, the specific process in the step S1) comprises the following steps: covering the surface of the melt by baking charcoal in the casting process at the casting temperature of 1150-1180 ℃ for up-drawing continuous casting to obtain KFC casting rods,

further, the KFC cast rod comprises the following components in percentage by mass: fe:0.05 to 0.15%, P:0.025 to 0.04%, sn:0 to 0.05 percent, and the balance of copper and inevitable impurities.

Further, the casting speed in the continuous extrusion process in the step S2) is 2.5-3.2m/min, and after continuous extrusion, an extruded plate blank with the thickness of 10mm-14mm is obtained, and the average grain size of the extruded plate blank is less than or equal to 20 microns.

Further, the aging treatment in the step S3) comprises the following specific processes: heating in a bell jar furnace at the heating speed of 50-100 ℃/min and the heating temperature of 400-600 ℃ for 3-10 h.

Further, the specific process of S4) is as follows:

s3.1) firstly carrying out multi-pass cooling, and carrying out cold rolling to obtain a strip with the thickness of 0.26mm-1.58mm;

s3.2) annealing at 400-650 deg.C and 30-70m/min, and the average grain size after annealing is less than or equal to 10 μm.

Further, the cold finish rolling process in the step S5) includes: and (3) carrying out cold finish rolling for multiple times, wherein the total deformation is 5-30%, and the thickness of the strip after finish rolling is 0.2-1.5 mm.

Furthermore, the tensile strength of the obtained fine-grain KFC strip can reach 420-470MPa, the elongation is 5-15%, the Vickers hardness is 120-135, the electric conductivity is more than or equal to 87% IACS, and the Vickers hardness is more than or equal to 115 after the temperature is kept for 3min at 470 ℃.

The fine-grain KFC strip is prepared by the method.

The invention has the advantages and beneficial effects that: by adopting the technical scheme, the preparation method has short flow, and can realize industrial and large-scale batch stable production;

and carrying out aging treatment after continuous extrusion, wherein on one hand, a large amount of second phases are precipitated in an aging way to ensure the requirement of the KFC strip on sufficient electric conductivity, and the grain structure is not obvious in the aging process at the stage, on the other hand, the aging at the stage can maximize the total deformation of cold rolling before air cushion furnace annealing, so that more recrystallization nucleation points are generated in the air cushion furnace annealing process to form more fine recrystallization grains, and finally, the KFC alloy strip with the tensile strength of 420-470MPa, the elongation of 5-15%, the Vickers hardness of 120-135, the electric conductivity of more than or equal to 87 IACS is prepared, and the Vickers hardness of more than or equal to 115 after the KFC alloy strip is kept at 470 ℃ for 3 min.

Drawings

Fig. 1 is a block flow diagram of a method of making a fine-grained KFC strip of the present invention.

FIG. 2 is a schematic metallographic view of a steel sheet obtained by cold finish rolling to 0.2mm according to example 1 of the present invention.

FIG. 3 is a schematic metallographic view showing the structure of a cold finish rolled to 0.6mm in example 2 of the present invention.

Detailed Description

The technical scheme of the invention is further explained by combining the drawings and the specific embodiments.

As shown in fig. 1, the method for preparing the fine-grained KFC strip of the present invention specifically comprises the following steps:

s1) preparing a KFC cast rod,

and S5) performing finish rolling on the strip annealed in the step S4), and cleaning, slitting and packaging to obtain the fine-grain KFC strip.

The specific process in the S1) comprises the following steps: covering the surface of the melt by baking charcoal in the casting process at the casting temperature of 1150-1180 ℃ for up-drawing continuous casting to obtain KFC casting rods,

the KFC cast rod comprises the following components in percentage by mass: fe:0.05 to 0.15%, P:0.025 to 0.04%, sn:0 to 0.05 percent, and the balance of copper and inevitable impurities.

And (3) carrying out continuous extrusion at a casting rod feeding speed of 2.5-3.2m/min in the S2), and obtaining an extruded plate blank with a thickness of 10mm-14mm, wherein the average grain size of the extruded plate blank is less than or equal to 20 mu m.

The specific process of the aging treatment in the S3) comprises the following steps: heating in a bell jar furnace at the heating speed of 50-100 ℃/min and the heating temperature of 400-600 ℃ for 3-10 h.

The specific process of S4) comprises the following steps:

s3.1) firstly, carrying out multi-pass cold rolling to obtain a strip with the thickness of 0.26mm to 1.58mm;

The finish rolling process in the S5) comprises the following steps: and (3) carrying out cold finish rolling for multiple times, wherein the total deformation is 5-30%, and the thickness of the strip after finish rolling is 0.2-1.5 mm.

The tensile strength of the obtained fine-grain KFC strip can reach 420-470 MPa, the elongation is 5-15%, the Vickers hardness is 120-135, the electric conductivity is more than or equal to 87% IACS, and the Vickers hardness is more than or equal to 115 after the temperature is kept for 3min at 470 ℃.

The fine-grain KFC strip is prepared by the method.

Example 1

The fine-grained KFC alloy strip with the thickness of 0.2mm is prepared by taking electrolytic copper as a raw material, adding a copper-iron intermediate alloy and a copper-phosphorus intermediate alloy, controlling the KFC alloy components to be 0.07 percent of Fe, 0.03 percent of P and the balance of copper and inevitable impurities. The copper alloy casting rod is prepared by an up-drawing continuous casting method, the casting temperature of the up-drawing continuous casting is 1150 ℃, and baking charcoal is adopted to cover the surface of a melt in the casting process. Continuously extruding the up-drawn continuous casting rod at a speed of 2.5m/min to obtain an extruded plate blank with the thickness of 12mm, wherein the average grain size of the extruded plate blank is less than or equal to 20 microns, heating in a bell jar furnace at a heating speed of 50 ℃/min at a heating value temperature of 400 ℃, keeping the temperature for 3h, and ensuring the electric conductivity to be 89.1 percent IACS and the Vickers hardness to be 101; and after continuous extrusion, cold rolling the steel strip into a strip with the thickness of 0.26mm for multiple times, annealing the steel strip by an air cushion furnace at the annealing temperature of 400 ℃ at the annealing speed of 30m/min, cold finish rolling the steel strip to 0.2mm after annealing, and cleaning, slitting and packaging the steel strip after the cold finish rolling. The KFC strip after cold finish rolling has the tensile strength of 434MPa, the elongation of 6.5 percent, the electric conductivity of 90.3 percent, the Vickers hardness of 127.5 percent, the Vickers hardness of 125.3 percent after the temperature is kept at 470 ℃ for 3min, and the average grain size of about 5 mu m, as shown in figure 1.

Example 2

Preparing a fine-grain KFC alloy strip with the thickness of 0.6mm, taking electrolytic copper as a raw material, adding a copper-iron intermediate alloy and a copper-phosphorus intermediate alloy, controlling the KFC alloy components to be 0.1 percent of Fe, 0.035 percent of P, and controlling the Sn: 0.02% and the balance copper and inevitable impurities. The copper alloy casting rod is prepared by an up-drawing continuous casting method, the casting temperature of the up-drawing continuous casting is 1180 ℃, and baking charcoal is adopted to cover the surface of a melt in the casting process. Preparing an extrusion plate blank with the thickness of 12mm by continuously extruding an up-drawing continuous casting rod, and performing in a bell jar furnace, wherein the heating speed is 70 ℃/min, the heating temperature is 500 ℃, the heat preservation time is 4h, the electric conductivity is 89.1% IACS, and the Vickers hardness is 101; and after continuous extrusion, carrying out multi-pass cold rolling to obtain a strip with the thickness of 0.7mm, then annealing in an air cushion furnace at the annealing temperature of 500 ℃ at the annealing speed of 50m/min, carrying out cold finish rolling to 0.6mm after annealing, and carrying out cleaning, slitting and packaging after the cold finish rolling. The tensile strength of the KFC strip after cold finish rolling is 423MPa, the elongation is 7.8 percent, the electric conductivity is 90.5 percent, the Vickers hardness is 123.5 percent, the Vickers hardness is 120.8 after the temperature is kept for 3min at 470 ℃, and the average grain size is about 9 mu m, as shown in figure 3.

Example 3

Preparing a fine-grain KFC alloy strip with the thickness of 0.8mm, taking electrolytic copper as a raw material, adding a copper-iron intermediate alloy and a copper-phosphorus intermediate alloy, controlling the KFC alloy components to be 0.1 percent of Fe, 0.035 percent of P, and controlling the Sn: 0.02% and the balance copper and inevitable impurities. The copper alloy cast rod is prepared by an up-drawing continuous casting method, the casting temperature of the up-drawing continuous casting is 1180 ℃, and baking charcoal is adopted to cover the surface of a melt in the casting process. Continuously extruding the continuous casting rod to prepare an extrusion plate blank with the thickness of 12mm, and heating in a bell jar furnace at the heating speed of 100 ℃/min, the heating temperature of 600 ℃, the heat preservation time of 10h, the electric conductivity of 90.1 percent IACS and the Vickers hardness of 101; and after continuous extrusion, cold rolling the steel strip into a strip with the thickness of 0.7mm for multiple times, annealing the steel strip by an air cushion furnace at the annealing temperature of 550 ℃ at the annealing speed of 60m/min, cold finish rolling the steel strip to 0.8mm after annealing, and cleaning, slitting and packaging the steel strip after the cold finish rolling. After cold finish rolling, the KFC strip has the tensile strength of 429MPa, the elongation of 8.8 percent, the electric conductivity of 92.5 percent, the Vickers hardness of 125.8 after heat preservation at 470 ℃ for 3min and the Vickers hardness of 122.6.

The method for preparing the fine-grain KFC strip and the fine-grain KFC strip provided by the embodiment of the application are described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The scope of the present application is to be construed in accordance with the substance defined by the following claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrases "comprising one of 8230; \8230;" 8230; "does not exclude the presence of additional like elements in articles of commerce or systems including such elements.

It should be understood that the term "and/or" as used herein is merely a relationship that describes an associated object, meaning that three relationships may exist, e.g., a and/or B, may represent: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, and is not to be construed as excluding other embodiments, but rather is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims

1. A method for preparing a fine-grained KFC strip, comprising the steps of:

s1) preparing a KFC cast rod;

in the continuous extrusion process, the casting speed is 2.5-3.2m/min, and after continuous extrusion, an extruded plate blank with the thickness of 10mm-14mm is obtained, and the average grain size of the extruded plate blank is less than or equal to 20 mu m;

the aging treatment comprises the following specific processes: heating in a bell jar furnace at the heating speed of 50-100 ℃/min and the heating temperature of 400-600 ℃ for 3-10 h;

s4.1) firstly carrying out multi-pass cold rolling to obtain a strip with the thickness of 0.26mm to 1.58mm; s4.2) annealing at 400-650 deg.C and 30-70m/min, with average grain size less than 10 μm;

s5) carrying out cold finish rolling on the strip annealed in the step S4), cleaning, slitting and packaging to obtain a fine-grain KFC strip;

the finish rolling process comprises the following steps: and (3) performing cold finish rolling for multiple times, wherein the total deformation is 5-30%, and the thickness of the strip after the cold finish rolling is 0.2-1.5 mm.

2. The method according to claim 1, wherein the specific process in S1) is: and covering the surface of the melt by baking charcoal in the casting process at the casting temperature of 1150-1180 ℃ for up-drawing continuous casting to obtain the KFC cast rod.

3. The method according to claim 1, wherein the KFC cast rod comprises the following components in percentage by mass: fe:0.05 to 0.15%, P:0.025 to 0.04%, sn:0 to 0.05 percent, and the balance of copper and inevitable impurities.

4. The method as claimed in claim 1, wherein the obtained fine-grained KFC strip has tensile strength of 420 to 470MPa, elongation of 5 to 15%, vickers hardness of 120 to 135, conductivity of more than or equal to 87% IACS, and Vickers hardness of more than or equal to 115 after heat preservation at 470 ℃ for 3 min.

5. A fine-grained KFC strip produced by the method of any of claims 1-4.