CN117305651A - Lead frame copper alloy strip with excellent comprehensive performance for packaging very large scale integrated circuit chip and preparation method thereof - Google Patents
Lead frame copper alloy strip with excellent comprehensive performance for packaging very large scale integrated circuit chip and preparation method thereof Download PDFInfo
- Publication number
- CN117305651A CN117305651A CN202311134945.8A CN202311134945A CN117305651A CN 117305651 A CN117305651 A CN 117305651A CN 202311134945 A CN202311134945 A CN 202311134945A CN 117305651 A CN117305651 A CN 117305651A
- Authority
- CN
- China
- Prior art keywords
- copper alloy
- alloy strip
- strip
- packaging
- integrated circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910000881 Cu alloy Inorganic materials 0.000 title claims abstract description 94
- 238000004806 packaging method and process Methods 0.000 title claims abstract description 27
- 238000002360 preparation method Methods 0.000 title claims description 13
- 238000005452 bending Methods 0.000 claims abstract description 42
- 239000006104 solid solution Substances 0.000 claims abstract description 23
- 238000005728 strengthening Methods 0.000 claims abstract description 13
- 238000001556 precipitation Methods 0.000 claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 3
- 229910052718 tin Inorganic materials 0.000 claims abstract description 3
- 238000005096 rolling process Methods 0.000 claims description 48
- 230000032683 aging Effects 0.000 claims description 29
- 239000013078 crystal Substances 0.000 claims description 25
- 238000010791 quenching Methods 0.000 claims description 24
- 230000000171 quenching effect Effects 0.000 claims description 24
- 239000010949 copper Substances 0.000 claims description 23
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 21
- 229910052802 copper Inorganic materials 0.000 claims description 21
- 238000002441 X-ray diffraction Methods 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 18
- 238000005098 hot rolling Methods 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 17
- 238000000137 annealing Methods 0.000 claims description 16
- 238000004321 preservation Methods 0.000 claims description 15
- 239000000243 solution Substances 0.000 claims description 10
- 230000008569 process Effects 0.000 claims description 9
- 239000000843 powder Substances 0.000 claims description 8
- 238000003723 Smelting Methods 0.000 claims description 7
- 238000005266 casting Methods 0.000 claims description 7
- 238000003801 milling Methods 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 6
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 239000011261 inert gas Substances 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 abstract description 12
- 230000008878 coupling Effects 0.000 abstract description 5
- 238000010168 coupling process Methods 0.000 abstract description 5
- 238000005859 coupling reaction Methods 0.000 abstract description 5
- 230000000903 blocking effect Effects 0.000 abstract description 4
- 238000005482 strain hardening Methods 0.000 abstract description 3
- 239000000956 alloy Substances 0.000 description 14
- 239000000047 product Substances 0.000 description 14
- 229910045601 alloy Inorganic materials 0.000 description 12
- 239000011159 matrix material Substances 0.000 description 11
- 239000000463 material Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000007789 gas Substances 0.000 description 5
- 239000002244 precipitate Substances 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 238000010606 normalization Methods 0.000 description 3
- 238000001953 recrystallisation Methods 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 229910017758 Cu-Si Inorganic materials 0.000 description 2
- 229910017931 Cu—Si Inorganic materials 0.000 description 2
- 238000003917 TEM image Methods 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000004080 punching Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000010008 shearing Methods 0.000 description 2
- 230000008054 signal transmission Effects 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 229910017818 Cu—Mg Inorganic materials 0.000 description 1
- 238000002083 X-ray spectrum Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
- C22C9/06—Alloys based on copper with nickel or cobalt as the next major constituent
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
- C22C1/03—Making non-ferrous alloys by melting using master alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/002—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working by rapid cooling or quenching; cooling agents used therefor
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/02—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working in inert or controlled atmosphere or vacuum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L23/00—Details of semiconductor or other solid state devices
- H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
- H01L23/488—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor consisting of soldered or bonded constructions
- H01L23/495—Lead-frames or other flat leads
- H01L23/49579—Lead-frames or other flat leads characterised by the materials of the lead frames or layers thereon
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Lead Frames For Integrated Circuits (AREA)
Abstract
The invention discloses a lead frame copper alloy strip for packaging a very large scale integrated circuit chip, which has excellent comprehensive performance, and comprises the following components in percentage by weight: ni:2.0 to 5.0 weight percent, co:0.01 to 1.0 weight percent, si:0.6 to 1.4 weight percent of Sn:0.01 to 1.0 weight percent, and the balance ofCu and unavoidable impurities. The copper alloy strip of the invention is made of Ni 2 Si、Co 2 Si、(Ni 1‑x Co x ) 2 The coupling of Si and precipitation phases is cooperated with strengthening and the solid solution strengthening of Sn element, and the blocking effect of the Kelvin gas group formed around dislocation by work hardening and Sn atoms on the dislocation is added, so that the yield strength of the copper alloy strip is improved; the copper alloy strip has considerable conductivity due to complete precipitation of solute atoms such as Ni, co, si and the like, improves bending performance, and is suitable for producing and manufacturing lead frames for packaging very large-scale integrated circuit chips.
Description
Technical Field
The invention relates to the field of copper alloy strips of stamping lead frames, in particular to a copper alloy strip of a lead frame for packaging a chip of an ultra-large scale integrated circuit with excellent comprehensive performance and a preparation method thereof.
Background
The lead frame mainly plays roles of supporting, radiating and transmitting signals to the chip. With the rapid development of chip technology, the integration level of chips is higher and higher, the pin number of a lead frame is more and more, the pin spacing is smaller and less, and more stringent requirements are put forward on the comprehensive performance and microstructure of the copper alloy strip of the lead frame. In order to ensure good support of the chip by the lead frame, the lead frame must have high mechanical properties; in order to ensure heat dissipation and excellent signal transmission of the chip, the lead frame must have high conductivity; in order to ensure industrial stamping of the lead frame, the lead frame material must have excellent bending workability. The development trend of high integration of chips brings out more severe requirements on the performances of yield strength, conductivity, bending and the like of copper alloy strips for lead frames, the yield strength of the copper alloy strips for lead frames for chip packaging is required to reach more than 850MPa, the conductivity reaches more than 45% IACS, and the bending performance is required to meet the requirement that Badway 90-degree bending R/t is less than or equal to 0 and is not cracked (R is bending radius and t is strip thickness).
Currently, copper alloy tapes for lead frames for chip packaging mainly include C19210, C19400, C15100, C18045, C70250, C70350, and the like. Although the alloy strips such as C19210, C19400, C15100 and C18045 have electric conductivity above 60% IACS, the requirements of good signal transmission and heat dissipation can be met, but the yield strength is only about 550MPa at most, and the requirements of mechanical properties of chip packages with smaller scale integration can be met; although the yield strength of the C70250 alloy strip corresponding to the state with the highest mechanical property can reach above 850MPa, the conductivity of the C70250 alloy strip in the state can only reach about 40% IACS, and the requirement of the conductivity required by the lead frame for packaging the next generation of the very large scale integrated circuit chip cannot be met; although the yield strength of the C70350 alloy strip can reach more than 850MPa and the conductivity can also reach more than 45% IACS, the mechanical property and the conductivity of the C70350 alloy strip can meet the performance requirements of the lead frame for packaging the next generation of very large scale integrated circuit chips, but the bending performance of the C70350 alloy strip can only reach Badway 90-degree bending R/t which is less than or equal to 1.5 and does not crack, and the bending performance of the C70350 alloy strip cannot meet the bending performance requirements of the lead frame for packaging the next generation of very large scale integrated circuit chips; on the other hand, in the application of the large-scale integrated circuit chip package, there is a case that the bending processing is required for the parts with larger width at the bending part, and the larger the width is, the more strict the requirement on the bending performance of the material is.
In addition, as the number of pins is increased and the pitch of the pins is reduced, if coarse precipitated phase particles exist in the microstructure of the copper alloy strip of the lead frame, after the strip is stamped, the precipitated phase particles with exposed stamped surfaces in the pins easily cause point discharge, so that short circuits occur among the pins. To avoid shorting of the pins, the precipitated phase particle size in the leadframe copper alloy strip needs to be controlled.
Disclosure of Invention
Aiming at the requirements of the lead frame for packaging the next generation of the very large scale integrated circuit chip on the yield strength, the conductivity and the bending performance of the copper alloy strip, the invention provides the copper alloy strip of the lead frame for packaging the very large scale integrated circuit chip, which has excellent comprehensive performance of strength, conductivity and bending performance, and a preparation method thereof.
The technical scheme adopted for solving the technical problems is as follows: the lead frame copper alloy strip for packaging the very large scale integrated circuit chip with excellent comprehensive performance comprises the following components in percentage by weight: ni:2.0 to 5.0 weight percent, co:0.01 to 1.0 weight percent, si:0.6 to 1.4 weight percent of Sn:0.01 to 1.0 weight percent, and the balance of Cu and unavoidable impurities.
In the invention, ni, co and Si are essential elements, and through solid solution and quenching treatment, ni, co and Si atoms are dissolved into a copper matrix in the solid solution treatment process and form a supersaturated solid solution through quenching treatment, and Ni is formed in the aging process 2 Si、Co 2 Si (Ni) 1-x Co x ) 2 The Si precipitated phase plays a role of dispersion strengthening, and improves the mechanical property of the copper alloy strip. In the aging process, ni is used as Ni, co and Si 2 Si、Co 2 Si (Ni) 1-x Co x ) 2 The Si precipitate phase is separated out from the copper matrix, so that the copper matrix is purified, and the conductivity of the copper alloy strip is improved. When the content of Ni, co and Si is too low, the Ni separated out after aging of the copper alloy strip of the invention 2 Si、Co 2 Si (Ni) 1-x Co x ) 2 The Si precipitation is less, the strengthening effect is not obvious, and the yield strength can not meet the requirement; on the contrary, when the content of Ni, co and Si in the copper alloy strip is too high, the dispersion strengthening phase precipitated by aging is too much, so that the scattering effect of precipitated phase particles on electron waves is increased, and the conductivity of the copper alloy strip is obviously reduced. Therefore, the content of Ni, co and Si in the copper alloy strip is controlled to be Ni:2.0 to 5.0 weight percent of Co:0.01 to 1.0 weight percent of Si:0.6 to 1.4 weight percent.
In the present invention, sn is an essential element and is dissolved in the copper alloy strip in the form of Sn atoms. The Sn atoms in the copper alloy strip material of the invention are solid-solved in the copper matrix to play a role of solid-solution strengthening, so that the mechanical property of the copper alloy strip material of the invention is improved. When the Sn content in the copper alloy strip is less than 0.01 weight percent, the blocking effect of Sn atoms on dislocation is not obvious, and the mechanical property of the copper alloy strip cannot be effectively improved; however, when the Sn content in the alloy strip of the present invention is more than 1.0wt%, although the mechanical properties of the copper alloy strip of the present invention can be greatly improved, excessive Sn atoms dissolved in the copper alloy can reduce the electrical conductivity of the copper alloy strip of the present invention, thereby deteriorating the electrical conductivity of the copper alloy strip of the present invention, and therefore the Sn content in the copper alloy strip of the present invention is controlled to be in the range of 0.01wt% to 1.0wt%, preferably 0.01wt% to 0.2wt%, and optimally.
As preferable: the X-ray diffraction intensity of the {111} crystal plane of the rolled surface of the copper alloy strip was designated as I {111}, and the X-ray diffraction intensity of the I {111} crystal plane of the pure copper standard powder was designated as I o {111}，I{111}/I o {111 }. Ltoreq.0.6; the X-ray diffraction intensity of the {220} crystal face of the rolled surface of the copper alloy strip was designated as I {220}, and the X-ray diffraction intensity of the I {220} crystal face of the pure copper standard powder was designated as I o {220}，I{220}/I o {220} -3.0; the X-ray diffraction intensity of the {311} crystal face of the rolled surface of the copper alloy strip was designated as I {311}, and the X-ray diffraction intensity of the I {311} crystal face of the pure copper standard powder was designated as I o {311}，I{311}/I o {311 }. Gtoreq.3.0. The {111} crystal face has the highest correlation with the crystal grain orientation of the original copper matrix, the microstructure changes in the plastic processing and heat treatment processes, crystal grains of the {111} plane are transformed into other surfaces, the crystal grains are crushed and thinned along with the increase of deformation, and the {220} crystal face orientation and the {311} crystal face orientation are gradually increased, so that a shearing deformation structure with preferred orientation is generated, and particularly, the {311} plane is easy to generate a fiber structure consistent with the shearing direction. The ratio of the X-ray diffraction intensity of the {111}, {220}, and {311} crystal faces of the rolled surface of the copper alloy strip to the X-ray diffraction intensity of the corresponding crystal face of the pure copper standard powder is within the range, so that the copper alloy strip has higher intensity and conductivity, improves bending performance of the strip, and has excellent performance under the condition of larger width of a bending part.
Preferably, the inventionNi in copper alloy strip 2 Si、Co 2 Si、(Ni 1-x Co x ) 2 The size of the Si precipitation strengthening phase particles is below 600 nm. Ni, co and Si elements form Ni in the aging process 2 Si、Co 2 Si (Ni) 1-x Co x ) 2 Si precipitated phase, three precipitated phase particles are below 600nm, and different types of precipitated phase particles have size difference, ni 2 Si、Co 2 Si (Ni) 1-x Co x ) 2 The three precipitated phases of Si have the synergistic coupling strengthening effect due to the difference of particle sizes, so that the purpose of improving the mechanical property of the copper alloy strip is achieved. And in which there are some of the components of relatively large size (Ni 1- x Co x ) 2 And when the size of the precipitated phase particles is overlarge, the exposed precipitated phase particles of the punching section in the pins easily cause point discharge after the subsequent punching processing of the alloy strip, so that short circuit occurs between the pins.
Preferably, the copper alloy strip of the present invention comprises, in addition to the main elements such as Ni, co, si, sn, one or more of the following optional elements in a total amount of less than 1 wt%: mg, zn, cr and Zr.
The main functions of Mg and Zn are to be solid-solution strengthened in the copper matrix, thereby being beneficial to improving the yield strength of the copper alloy strip. When the content of Mg and Zn is too low, the effect of improving the yield strength of the copper alloy strip is not obvious; when the content of Mg and Zn is too high, excessive Mg and Zn are dissolved in the copper matrix in a solid manner, so that the scattering of electron waves is improved, and the conductivity of the copper alloy strip is reduced.
Cr atoms and Zr atoms in the invention form Cr 2 Zr precipitated phase and precipitated Ni 2 Si、Co 2 Si、(Ni 1-x Co x ) 2 The Si and other precipitate phases play a role in cooperative coupling dispersion strengthening, and are helpful for further improving the yield strength of the copper alloy strip. If the content of the optional elements Cr and Zr in the copper alloy strip is too low, the effect is not obvious; conversely, if too high, too much Cr will be precipitated 2 Zr precipitates, increases scattering of electron waves, and leads to poor conductivity of the copper alloy strip.
Preferably, the yield strength of the copper alloy strip is more than or equal to 850MPa, the conductivity is more than or equal to 45 percent IACS, and the bending limit width of the copper alloy strip is more than 20mm when the copper alloy strip is bent by Badway90 degrees and the ratio R/t=0 of the bending radius R to the thickness t of the copper alloy strip.
The whole process preparation procedure of the copper alloy strip comprises the following steps: batching, smelting and casting, sawing, hot rolling and cogging, milling faces, rough rolling, solid solution and quenching, intermediate rolling, aging, finish rolling, low-temperature annealing, stretch bending and straightening, and obtaining a strip product, wherein the low-temperature annealing temperature is 300-350 ℃, and the heat preservation time is 4-6 hours.
In the preparation process of the copper alloy strip, the smelting temperature of the copper alloy is 1200-1250 ℃, so that various added materials are ensured to be fully melted. The casting temperature is 1160-1200 ℃, and the fluidity of the copper alloy melt is ensured. The elements such as Mg, zr, si and the like are added in the form of Cu-Mg, cu-Zr and Cu-Si intermediate alloy during smelting.
In the preparation process of the copper alloy, the hot rolling heating temperature is 900-920 ℃, and the heating and heat preserving time is 3-5 hours, so that the temperature uniformity of a plate blank is ensured. The hot rolling start temperature of the copper alloy strip is controlled within the range of 900-920 ℃, the total hot rolling processing rate is more than 90 percent, preferably, the final hot rolling temperature is kept above 750 ℃, the hot rolling is finished at above 750 ℃, dynamic recrystallization can occur, and the rolling surface I {311}/I of the hot rolled strip obtained after hot rolling cogging is ensured o {311} > 4.0, is beneficial to obtaining the final strip product with the required consistent crystal plane orientation. If the final rolling temperature of the hot rolling is lower than 750 ℃, the dynamic recrystallization in the hot rolling process is insufficient, and the rolling surface I {311}/I of the hot rolled strip is o {311} can not reach more than 4.0, and the crystal plane orientation of the rolled surface of the copper alloy strip cannot be ensured to be consistent after the subsequent surface milling, rough rolling, solid solution and quenching treatment, so that the bending performance is poor.
Preferably, in order to ensure complete recrystallization during solution treatment, the strip is subjected to rough rolling at a total working rate of 90% or more prior to solution treatment, thereby ensuring solidificationAfter dissolution and quenching treatment, the rolled surface I {220}/I of the copper alloy strip of the invention o {220 }. Ltoreq.2.0. If the total roughing reduction before solution treatment is less than 90%, the strip after solution treatment has a rolled surface of I {220}/I due to insufficient energy storage o Failure of 220 to reach below 2.0 results in a finished strip with bending properties that do not meet the desired requirements.
Preferably, in the invention, the solid solution temperature of the copper alloy strip is controlled to be 1020-1040 ℃, and the heat preservation time is 30-150 seconds. The strip is subjected to solution treatment at 1020-1040 ℃, firstly, solute atoms such as Ni, co, si, sn, mg, zn, cr, zr and the like are ensured to be completely dissolved in a copper matrix to form a supersaturated solid solution, so that enough precipitated phases are conveniently separated out in the subsequent aging treatment process, and the yield strength of the strip is ensured to reach above 850 MPa; secondly, ensuring the I {220}/I of the strip rolling surface o {220 }. Ltoreq.2.0. The solution treatment time is 30 to 150 seconds, and the purpose is to allow a sufficient diffusion time of solute atoms such as Ni, co, si, sn, mg, zn, cr, zr during the solution treatment, thereby forming a supersaturated solid solution. The heat preservation time is lower than 30 seconds, which can lead to insufficient solid solution of solute atoms such as Ni, co, si, sn, mg, zn, cr, zr and the like, and can not form enough precipitation strengthening phases after aging treatment, so that the yield strength of the strip can not reach more than 850 MPa; the heat preservation time exceeds 150 seconds, which can lead to coarse grains (more than or equal to 15 mu m) and lead the bending performance of the finished product of the strip to be unable to meet the requirement.
Preferably, the copper alloy strip of the present invention is solution treated and then subjected to an in-line two-step continuous quenching: the first step of quenching is carried out in a salt bath, the strip is cooled to below 600 ℃ with the cooling speed of above 100 ℃/s; then quenching is carried out in the second step, the quenching is carried out in inert gas, the strip is cooled to room temperature, and the cooling speed is more than 150 ℃/s. After the strip is subjected to solid solution and online continuous two-step quenching treatment, a supersaturated solid solution is formed, crystal nuclei precipitated by a precipitated phase in the subsequent aging treatment process are formed in the strip, and the size of the precipitated phase particles in the aging treatment process is regulated and controlled, so that the size of the precipitated phase particles in the finished product of the strip is controlled below 600nm, and the copper alloy strip is ensured to be manufactured into a lead frame for packaging an ultra-large-scale integrated circuit chip through stamping, and short circuit among pins of the lead frame cannot be caused due to the existence of coarse precipitated phase particles above 600 nm.
Preferably, the copper alloy strip is subjected to intermediate rolling after being subjected to solid solution and quenching, the intermediate rolling processing rate is controlled to be more than 60%, and the intermediate rolling processing rate is reserved for precipitation of a precipitated phase in the aging treatment process. If the working ratio of the intermediate rolling is lower than 60%, the energy storage is insufficient, a precipitated phase cannot be completely separated out in the aging treatment process, and part of solute atoms are also dissolved in the copper matrix in a solid manner, so that the yield strength and the conductivity of the finished strip product are poor.
The copper alloy strip is subjected to ageing treatment after being rolled in the copper alloy strip, the ageing temperature is 400-450 ℃, and the heat preservation time is 6-10 hours. The purpose of the ageing treatment is to precipitate Ni in the strip 2 Si、Co 2 Si、(Ni 1-x Co x ) 2 Simple substance of Si and Cr 2 Zr and the like, and the precipitation phases play a role of coupling synergistic reinforcement. In addition, the precipitate phase is separated out from the copper matrix, so that the concentration of solute atoms in the copper matrix is greatly reduced, and the conductivity of the strip is improved. The aging temperature of the copper alloy strip is 400-450 ℃ and the heat preservation time is 6-10 h optimally. If the aging temperature is lower than 400 ℃, solute atoms cannot be precipitated; if the aging temperature is higher than 450 ℃, coarse grains of the finished product can be caused, and the bending performance of the strip is reduced. If the aging heat preservation time is less than 6 hours, enough precipitated phases cannot be formed, which is not beneficial to improving the yield strength; if the aging heat preservation time is more than 10 hours, the grains of the strip material are coarse, which is unfavorable for improving the strength and bending performance of the strip material.
Preferably, the copper alloy strip is subjected to finish rolling after aging treatment, and the finish rolling rate is controlled to be 10% -20%. According to the invention, a large number of dislocation can be formed around the precipitated phase through finish rolling after aging treatment, so that the yield strength of the strip is further improved. If the finish rolling rate is less than 10%, the work hardening effect is poor, resulting in insufficient yield strength improvement of the finished strip product; if the finish rolling is performed at a processing rate higher than 20%, the yield strength of the finished strip product is greatly improved, but the control of the orientation of each crystal plane of the rolled surface of the finished strip product is adversely affected, resulting in a reduction in bending performance of the strip.
The copper alloy strip is subjected to low-temperature annealing treatment after finish rolling processing, wherein the low-temperature annealing temperature is 300-350 ℃, and the heat preservation time is 4-6 hours. Through low-temperature annealing treatment, sn atoms can be distributed along dislocation in the crystal to form a Korotkoff gas group, so that the blocking effect on the dislocation is increased, and the yield strength of the strip is further improved. When the low-temperature annealing temperature is lower than 300 ℃, the formation of the Kelvin gas mass cannot be promoted, and the improvement of the yield strength is not facilitated; when the low temperature annealing temperature is higher than 350 ℃, the aging precipitate phase is caused to coarsen, thereby lowering the yield strength of the strip. When the heat preservation time of low-temperature annealing is less than 4 hours, the annealing time is too short, which is not beneficial to forming a Korotkoff gas mass; when the heat preservation time of low-temperature annealing is higher than 6 hours, sn atoms are agglomerated at dislocation, and the effect of improving yield strength by the Kelvin gas mass is reduced.
The copper alloy strip is annealed at low temperature and is subjected to stretch bending straightening treatment after being cleaned, so that the shape of the strip is improved.
Compared with the prior art, the invention has the advantages that: the copper alloy strip of the invention is made of Ni 2 Si、Co 2 Si、(Ni 1- x Co x ) 2 The coupling of Si and precipitation phases is cooperated with strengthening and the solid solution strengthening of Sn element, and the blocking effect of the Kelvin gas group formed around dislocation by work hardening and Sn atoms on the dislocation is added, so that the yield strength of the copper alloy strip is improved; the copper alloy strip has considerable conductivity due to complete precipitation of solute atoms such as Ni, co, si and the like, improves bending performance, and is suitable for producing and manufacturing lead frames for packaging very large-scale integrated circuit chips.
Drawings
FIG. 1 is an X-ray diffraction pattern of a strip sample prior to rolling surface normalization of example 2;
FIG. 2 is a transmission electron micrograph of a sample of the example 2 tape.
Detailed Description
The present invention will be described in further detail with reference to the following examples and comparative examples of the accompanying drawings.
25 example alloy materials are selected, and all the example alloy materials are processed into strip finished products with the thickness of 0.2mm by adopting the full-flow preparation process and the full-flow preparation technology. The copper alloy strip with high yield strength, good conductivity and excellent bending and forming properties has the following preparation procedures: batching, smelting and casting, sawing, hot rolling and cogging, milling faces, rough rolling, solid solution and quenching, intermediate rolling, aging, finish rolling, low-temperature annealing, stretch bending and straightening, and obtaining a strip finished product, wherein the method specifically comprises the following steps of:
1) Batching and casting: raw material preparation and batching were carried out according to the chemical compositions shown in table 1, smelting was carried out by using an induction furnace, and the addition sequence of the alloy was: cu is added firstly, ni and Co are added after melting, sn and Cu-Si intermediate alloy is added after melting Ni and Co, and one or more elements in Mg, zn, cr, zr are selectively added. Detecting components by adopting an ICP method, casting after the components meet the requirements and are fully deaerated and deslagged, wherein the smelting temperature is 1220 ℃, and the casting temperature is 1180 ℃.
2) Sawing: sawing the cast ingot to remove the head and tail of the cast ingot.
3) Hot rolling cogging: heating the cast ingot at 900-920 ℃, preserving heat for 3-5 h, performing hot rolling cogging, wherein the hot rolling cogging temperature is 900-920 ℃, the total hot rolling processing rate is above 90%, and the final rolling temperature is above 750 ℃.
4) Milling: and (3) carrying out surface milling treatment on the hot rolled strip to remove oxides on the surface of the strip.
5) Rough rolling: and (3) carrying out rough rolling processing on the strip after the surface milling, wherein the total processing rate of the rough rolling processing is more than 90%.
6) Solid solution and quenching: after rough rolling, carrying out solid solution and quenching treatment on the strip, wherein the solid solution temperature is 1020-1040 ℃, the heat preservation time is 30-150 seconds, then carrying out online continuous two-step quenching treatment, wherein the first-step quenching treatment is carried out in a salt bath, and the strip is cooled to below 600 ℃ with the cooling speed of above 100 ℃/s; the second quenching is carried out in inert gas, the strip is cooled to room temperature, and the cooling speed is more than 150 ℃/s.
7) And (3) middle rolling: and cleaning the strip subjected to solution and quenching treatment, and then performing intermediate rolling processing, wherein the intermediate rolling processing rate is controlled to be more than 60%.
8) Aging: aging treatment is carried out on the strip after the intermediate rolling, the aging temperature is 400-450 ℃, and the heat preservation time is 6-10 h.
9) Finish rolling: and (3) cleaning the strip subjected to aging treatment, and then performing finish rolling processing, wherein the finish rolling processing rate is 10% -20%.
10 Low temperature annealing): and (3) carrying out low-temperature annealing treatment on the strip after finish rolling processing, wherein the low-temperature annealing temperature is 300-350 ℃, and the heat preservation time is 4-6 h.
11 Stretch bending and straightening: and (3) stretch bending and straightening the strip after finish rolling processing, and controlling the shape of the strip to obtain a copper alloy strip finished product of which the shape meets the application requirements of the lead frame for packaging the very large-scale integrated circuit chip.
And (3) carrying out yield strength, conductivity, bending performance, X-ray diffraction and transmission electron microscope detection and analysis on the strips of the embodiment.
Yield strength test according to GB/T228.1-2021 section 1 tensile test of metallic materials: the room temperature test method is carried out on an electronic universal mechanical property tester, and a strip sample with the thickness of 0.2mm is adopted in the embodiment, and the stretching speed is 5mm/min.
The conductivity of the example strips was tested using the GB/T32791-2016 copper and copper alloy conductivity vortex test method.
The bending performance of the strip of the examples was tested by using JCBAxT307-2007 Test method of bend formability for sheets and strips of copper and copper alloys, the length of the sample was 30mm, the width of the sample was 10, 15, 20, 25, 30, 35, 40, 45, 50 samples of nine different specifications were taken, a 90 ° bending test was performed on the condition that the ratio of the bending radius R to the thickness t of the strip was=0, no cracking was observed after the test, and the ultimate bending width of the strip samples of the examples was tested.
Analyzing the rolled surface of the strip by adopting X-ray diffraction to obtain a diffraction pattern, and then carrying out the patternPerforming normalization treatment and comparing with X-ray spectrum of pure copper standard powder, and calculating rolling surface I {111}/I of each embodiment belt material o {111}、I{220}/I o {220}、I{311}/I o {311} value.
And analyzing the microstructure of the finished product of the strip by adopting a transmission electron microscope, randomly selecting ten visual areas, and measuring the size of the largest precipitated phase particles by using software of the transmission electron microscope equipment, wherein the size of the precipitated phase particles is the length of the longest line segment passing through the particles.
The X-ray diffraction pattern of the strip sample of example 2 before rolling surface normalization treatment is shown in fig. 1; example 2 a transmission electron micrograph of a sample of the tape is shown in figure 2.
The components, specific preparation process and detection results of microstructure and performance of the finished product of the strip are shown in tables 1, 2 and 3.
As shown in table 3, the yield strength of the embodiment of the invention reaches above 850MPa, the conductivity reaches above 45% iacs, the bend limit width of the bend radius R and the ratio R/t=0 of the strip thickness t is above 20mm when the bend is bent by 90 ° in Badway, and the yield strength, the conductivity and the bending performance meet the use requirements of the lead frame for packaging the new generation of very large scale integrated circuit chips.
Table 1 Components of examples
/>
Claims (10)
1. The lead frame copper alloy strip for packaging the chip of the very large scale integrated circuit with excellent comprehensive performance is characterized in that: the copper alloy strip comprises the following components in percentage by weight: ni:2.0 to 5.0 weight percent, co:0.01 to 1.0 weight percent, si:0.6 to 1.4 weight percent of Sn:0.01 to 1.0 weight percent, and the balance of Cu and unavoidable impurities.
2. The excellent-combination-property copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit according to claim 1, wherein:
the X-ray diffraction intensity of the {111} crystal plane of the rolled surface of the copper alloy strip was designated as I {111}, and the X-ray diffraction intensity of the I {111} crystal plane of the pure copper standard powder was designated as I o {111}，I{111}/I o {111}≤0.6；
The X-ray diffraction intensity of the {220} crystal face of the rolled surface of the copper alloy strip was designated as I {220}, and the X-ray diffraction intensity of the I {220} crystal face of the pure copper standard powder was designated as I o {220}，I{220}/I o {220}≤3.0；
The X-ray diffraction intensity of the {311} crystal face of the rolled surface of the copper alloy strip was designated as I {311}, and the X-ray diffraction intensity of the I {311} crystal face of the pure copper standard powder was designated as I o {311}，I{311}/I o {311}≥3.0。
3. The excellent-combination-property copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit according to claim 1, wherein: ni in the copper alloy strip 2 Si、Co 2 Si、(Ni 1-x Co x ) 2 The size of the Si precipitation strengthening phase particles is below 600 nm.
4. The excellent-combination-property copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit according to claim 1, wherein: the copper alloy strip also comprises one or more of the following optional elements in a total amount of less than 1 wt%: mg, zn, cr and Zr.
5. The copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit excellent in combination as set forth in any one of claims 1 to 4, wherein: the yield strength of the copper alloy strip is more than or equal to 850MPa, the conductivity is more than or equal to 45% IACS, the Badway 90-degree bending is carried out, and the bending limit width when the ratio R/t=0 of the bending radius R to the thickness t of the strip is more than 20 mm.
6. The method for producing a copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit excellent in combination properties according to any one of claims 1 to 4, characterized by: the whole process preparation procedure of the copper alloy strip comprises the following steps: batching, smelting and casting, sawing, hot rolling and cogging, milling faces, rough rolling, solid solution and quenching, intermediate rolling, aging, finish rolling, low-temperature annealing, stretch bending and straightening, and obtaining a strip product, wherein the low-temperature annealing temperature is 300-350 ℃, and the heat preservation time is 4-6 hours.
7. The method for manufacturing a copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit excellent in combination as set forth in claim 6, wherein: the final rolling temperature of the hot rolling is above 750 ℃, and the I {311}/I of the strip rolling surface after hot rolling cogging o {311}≥4.0。
8. The method for manufacturing a copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit excellent in combination as set forth in claim 6, wherein: the total processing rate of rough rolling is controlled to be more than 90 percent, the solid solution temperature is controlled to be 1020-1040 ℃, and the I {220}/I of the strip rolling surface after solid solution and quenching treatment o {220}≤2.0。
9. The method for manufacturing a copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit excellent in combination as set forth in claim 6, wherein: carrying out online continuous two-step quenching after solution treatment: the first step of quenching is carried out in a salt bath, the strip is cooled to below 600 ℃ with the cooling speed of above 100 ℃/s; then quenching is carried out in the second step, the quenching is carried out in inert gas, the strip is cooled to room temperature, and the cooling speed is more than 150 ℃/s.
10. The method for manufacturing a copper alloy strip for a lead frame for packaging a chip of a very large scale integrated circuit excellent in combination as set forth in claim 6, wherein: the processing rate of the intermediate rolling is controlled to be more than 60 percent, and the processing rate of the finish rolling is controlled to be 10 to 20 percent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311134945.8A CN117305651A (en) | 2023-09-05 | 2023-09-05 | Lead frame copper alloy strip with excellent comprehensive performance for packaging very large scale integrated circuit chip and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311134945.8A CN117305651A (en) | 2023-09-05 | 2023-09-05 | Lead frame copper alloy strip with excellent comprehensive performance for packaging very large scale integrated circuit chip and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117305651A true CN117305651A (en) | 2023-12-29 |
Family
ID=89285678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311134945.8A Pending CN117305651A (en) | 2023-09-05 | 2023-09-05 | Lead frame copper alloy strip with excellent comprehensive performance for packaging very large scale integrated circuit chip and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117305651A (en) |
-
2023
- 2023-09-05 CN CN202311134945.8A patent/CN117305651A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111485132B (en) | Copper alloy strip with excellent comprehensive performance and preparation method thereof | |
| US11655524B2 (en) | Copper alloy with excellent comprehensive performance and application thereof | |
| TWI381398B (en) | Cu-Ni-Si alloy for electronic materials | |
| TWI622658B (en) | Copper alloy plate and manufacturing method of copper alloy plate | |
| JP3699701B2 (en) | Easy-to-process high-strength, high-conductivity copper alloy | |
| WO2012121109A1 (en) | Cu-Ni-Si BASED ALLOY AND PROCESS FOR MANUFACTURING SAME | |
| EP2641983A1 (en) | Cu-Ni-Si-Co COPPER ALLOY FOR ELECTRON MATERIAL AND METHOD FOR PRODUCING SAME | |
| TWI626323B (en) | Copper alloys for electronic materials | |
| TWI516617B (en) | Cu-Si-Co based copper alloy for electronic materials and its manufacturing method | |
| WO2013018228A1 (en) | Copper alloy | |
| TWI429768B (en) | Cu-Co-Si based copper alloy for electronic materials and method for producing the same | |
| TW201309817A (en) | Cu-ni-si alloy and method for manufacturing same | |
| CN113913642B (en) | Copper alloy strip and preparation method thereof | |
| JP4653240B2 (en) | Copper alloy materials and electrical / electronic parts for electrical / electronic equipment | |
| JP2011038126A (en) | Cu-Ni-Si-BASED ALLOY PLATE OR BAR FOR ELECTRONIC MATERIAL | |
| CN114855026B (en) | High-performance precipitation strengthening type copper alloy and preparation method thereof | |
| JP3511648B2 (en) | Method for producing high-strength Cu alloy sheet strip | |
| TWI527914B (en) | Strength, heat resistance and bending workability of the Fe-P copper alloy plate | |
| CN115386767B (en) | Lead frame copper alloy strip for packaging ultra-large scale integrated circuit chip and preparation method thereof | |
| JP2006016629A (en) | Cu-Ni-Si BASED COPPER ALLOY STRIP HAVING EXCELLENT BENDING WORKABILITY IN BAD WAY | |
| CN112501472B (en) | High-performance copper alloy strip and preparation method thereof | |
| JP2011246740A (en) | Cu-Co-Si BASED ALLOY SHEET OR STRIP FOR ELECTRONIC MATERIAL | |
| CN117305651A (en) | Lead frame copper alloy strip with excellent comprehensive performance for packaging very large scale integrated circuit chip and preparation method thereof | |
| JPH0617209A (en) | Manufacture of copper alloy for electrical and electronic apparatus | |
| JP7311651B1 (en) | Copper alloys for electronic materials and electronic parts |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |