High-stability semiconductor lead frame and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor lead frames, in particular to a high-stability semiconductor lead frame and a preparation method thereof.The preparation method comprises the following steps that 1, copper, nickel, silicon, chromium, phosphorus and modified titanium boride are subjected to ball milling together to obtain mixed powder; 2, the mixed powder is put into a mold for cold press molding, and a green body is obtained; 3, the green body is subjected to sintering treatment and solution treatment, and a composite block is obtained; 4, cold-rolling the composite block into a strip, and performing aging treatment to obtain a composite material; step 5, performing punch forming on the composite material to obtain a semi-finished product of the high-stability semiconductor lead frame; 6, carrying out alkali washing on the semi-finished product, then putting the semi-finished product into a hydrochloric acid solution for derusting, and finally carrying out acid pickling activation to obtain an activated semi-finished product of the high-stability semiconductor lead frame; and 7, putting the activated semi-finished lead frame product into a chemical plating solution composed of nickel, tungsten, phosphorus and a graphene composite material for electroplating, and then drying to obtain the finished high-stability semiconductor lead frame.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor lead frame, in particular to a high-stability semiconductor lead frame and a preparation method thereof. BACKGROUND

[0002] The semiconductor lead frame is a key carrier in integrated circuit packaging, which bears the core functions of supporting chips, connecting internal and external circuits, conducting current and dissipating heat, and is known as the "skeleton" of integrated circuits. Its performance directly affects the reliability, stability and service life of the device.

[0003] Copper becomes the main matrix material of the lead frame due to its good electrical conductivity and thermal conductivity. However, pure copper has insufficient strength and is difficult to meet the mechanical performance requirements in the packaging process. Usually, the strength is improved by alloying, but the addition of alloying elements often significantly reduces the electrical conductivity, resulting in a conflict between strength and electrical performance. In addition, the existing traditional copper alloy lead frame is prone to softening under high temperature environment, has insufficient heat resistance, and can cause delamination, warping or even cracking of the packaging body due to mismatch of the thermal expansion coefficient. In long-term use, it may also have problems such as electrochemical migration, oxidation and plating layer peeling, which seriously affect the soldering reliability and signal integrity.

[0004] Therefore, it has become an urgent technical problem to be solved in the field of semiconductor packaging to develop a high-stability lead frame that can significantly improve the strength, heat resistance, corrosion resistance and plating layer adhesion while maintaining good electrical conductivity. SUMMARY

[0005] The purpose of the present application is to provide a high-stability semiconductor lead frame and a preparation method thereof to solve the problems existing in the prior art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions: Step 1: ball milling copper, nickel, silicon, chromium, phosphorus and modified titanium boride together to obtain a mixed powder; Step 2: loading the mixed powder into a mold and cold pressing to form a green body; Step 3: after sintering treatment, the green body is subjected to solid solution treatment and then water quenching to obtain a composite block; Step 4: cold rolling the composite block into a strip and performing aging treatment to obtain a composite material; Step 5: forming the composite material by stamping to obtain a semi-finished product of the high-stability semiconductor lead frame; Step 6: placing the semi-finished product of the high-stability semiconductor lead frame in a lye for alkaline washing, then taking it out and ultrasonic cleaning in deionized water, then taking it out and ultrasonic treating in a hydrochloric acid solution, then ultrasonic cleaning in deionized water, and finally placing it in a hydrofluoric acid solution for acid washing and activation to obtain the semi-finished product of the high-stability semiconductor lead frame after activation. Step 7: sodium citrate, nickel sulfate, sodium tungstate, sodium hypophosphite, sodium acetate and graphene composite material are sequentially added into ultrapure water to be dissolved under ultrasonic stirring, and sodium hydroxide solution is added to adjust the pH value of the solution to 8.0~8.2, to obtain a chemical plating solution; the activated high-stability semiconductor lead frame semi-finished product is placed in the chemical plating solution for electroplating, and after being taken out, it is ultrasonically cleaned in deionized water and dried to obtain a finished high-stability semiconductor lead frame.

[0007] Further, the components of the mixed powder are, by mass percentage, nickel 1.30%~2.10%, silicon 0.50%~1.00%, chromium 0.80%~1.20%, phosphorus 0.01%~0.05%, modified titanium boride 1%~2%, and the balance being copper and unavoidable impurities.

[0008] Further, the ball milling process conditions in step 1 are a rotation speed of 650~850 r / min and a time of 1~2 h; the pressure conditions for cold pressing in step 2 are 400~600 MPa; the sintering treatment conditions in step 3 are a temperature of 800~850℃ and a time of 2~3 h, and the solid solution treatment conditions are a temperature of 850~1000℃ and a time of 2~3 h; the thickness of the strip in step 4 is 0.1~0.3 mm, the cold rolling process conditions are a temperature of 200~300℃, and the aging treatment conditions are a temperature of 400~480℃ and a time of 2~3 h.

[0009] Further, the alkali washing conditions in step 6 are heating in a 70~75℃ water bath for 15~20 min, the ultrasonic cleaning time with deionized water twice is 1~2 min, the ultrasonic treatment time with hydrochloric acid solution is 2~4 min, and the activation conditions of the hydrofluoric acid solution are heating in a 70~75℃ water bath for 2~4 min; the ultrasonic stirring time in step 7 is 30~35 min, and the electroplating conditions are a temperature of 83~87℃ and a current density of 4~6 A / dm 2 The ultrasonic stirring time is 30~35 min, and the deionized water ultrasonic cleaning time is 30~60 s.

[0010] Further, the alkali solution in step 6 is mixed by sodium carbonate, sodium hydroxide and deionized water in a mass ratio of 4:1:200, the mass concentration of the hydrochloric acid solution is 10%, and the mass concentration of the hydrofluoric acid solution is 5%; the sodium citrate, nickel sulfate, sodium tungstate, sodium hypophosphite, sodium acetate, graphene composite material and ultrapure water in step 7 are mixed in a mass ratio of 0.7:0.4:0.7:0.5:0.4:0.02:20, and the concentration of the sodium hydroxide solution is 1 mol / L.

[0011] Further, the preparation steps of the modified titanium boride are as follows: Mix isopropyl alcohol with deionized water, stir until uniform, add γ-methacryloyloxypropyl trimethoxysilane drop by drop, then continue stirring for 1-2 h to obtain a silane coupling agent solution; add titanium boride, stir until mixed uniformly to obtain a mixture; the mixture is initially dried at 80-85°C, then heated to 120-125°C for drying, ground to obtain modified titanium boride.

[0012] Further, the isopropyl alcohol and deionized water are mixed at a mass ratio of 6:1, and the mass of γ-methacryloyloxypropyl trimethoxysilane is 3% of the mass of titanium boride.

[0013] Further, the preparation steps of the graphene composite material are as follows: S1: Dissolve tris-hydroxymethyl aminomethane in deionized water, and adjust the pH to 8.7-8.9 with ammonium chloride to prepare a buffer solution; add 2-mercaptobenzothiazole and copper nitrate trihydrate to the buffer solution at 20-25°C, and stir for 30-35 min to obtain a thiazole-containing corrosion inhibitor precursor modified with copper ions; S2: Dissolve cobalt nitrate hexahydrate in methanol to obtain a cobalt nitrate hexahydrate solution; dissolve 2-methyl imidazole in methanol to obtain a 2-methyl imidazole solution; add the thiazole-containing corrosion inhibitor precursor modified with copper ions to the cobalt nitrate hexahydrate solution, stir for 5-8 min, then add the 2-methyl imidazole solution, and continue stirring for 5-8 min to obtain a suspension; after the suspension is reacted at 150-170°C for 22-26 h, centrifugal separation is performed, washing is performed 3-5 times with ethanol, drying is performed at 60-65°C for 22-26 h, and grinding is performed to obtain a zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite; S3: Weigh graphene, disperse it in methanol, and ultrasonic treat for 2-3 h to obtain a uniform graphene colloidal solution; mix the graphene colloidal solution and the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite, magnetically stir at 20-25°C for 22-26 h, then wash 3-5 times with methanol, and dry at 80-85°C for 22-26 h to obtain a graphene composite material.

[0014] Further, the buffer concentration in S1 is 1.30 mol / L, and 2-mercaptobenzothiazole and copper nitrate trihydrate are mixed at a molar ratio of 2:1; in S2, the cobalt nitrate hexahydrate solution and methanol are mixed at a mass ratio of 1:100, and 2-methyl imidazole and methanol are mixed at a mass ratio of 1:25; in S3, the graphene and methanol are mixed at a mass ratio of 3:500.

[0015] Compared with the prior art, the present application has the following advantages: 1. The application describes a high-stability semiconductor lead frame and its preparation method, which uses copper, nickel, silicon, chromium and phosphorus as metal materials, adds modified titanium boride to the metal materials for ball milling, and then prepares a Cu-Ni-Si / titanium boride composite material through cold pressing, sintering, solid solution, cold rolling and aging treatment, finally forms through stamping, and activates and pretreats the formed semi-finished product, and then electroplates a layer of Ni-W-P / graphene composite coating thereon to obtain a high-stability semiconductor lead frame with high strength, high conductivity, corrosion resistance and oxidation resistance.

[0016] 2. The application describes a high-stability semiconductor lead frame and its preparation method, which realizes synergistic strengthening of multiple metal elements: the copper matrix guarantees the conductivity and thermal conductivity; the nickel improves the strength and softening resistance through solid solution strengthening; the silicon and nickel form a high-temperature stable Ni2Si precipitated phase, which endows the material with core strength and fatigue resistance; the chromium enhances the oxidation resistance and heat resistance; the phosphorus purifies the alloy as a deoxidizer to improve the toughness; the added γ-methacryloxypropyl trimethoxysilane modified titanium boride solves the interface bonding problem of ceramic reinforced phase and metal matrix through molecular bridge effect, and the highly dispersed TiB2 particles significantly improve the strength, hardness and wear resistance of the material through dispersion strengthening, and serve as heterogeneous nucleation points to refine the grains and improve the comprehensive performance. These components together form a strengthened matrix that can still maintain stable mechanical and electrical properties under extreme working conditions, providing a bearing foundation for the subsequent coating.

[0017] 3. The application describes a high-stability semiconductor lead frame and its preparation method, which completely removes the oil stains on the surface of the semiconductor lead frame through saponification and emulsification reaction of alkaline solution, providing a clean interface for subsequent steps; then effectively dissolves metal oxide stains through pickling reaction of hydrochloric acid to expose the fresh matrix; finally, using the unique complexing and micro-etching ability of hydrofluoric acid, removes the inert oxide layer containing silicon and chromium and performs micro-roughening on the surface, increases the adhesion of the subsequent coating, realizes the surface super-clean, creates a substrate with high activity and micro-anchoring structure, and provides strong bonding force and compactness guarantee for the subsequent coating.

[0018] 4. The application describes a high-stability semiconductor lead frame and its preparation method, which uses Ni-W-P / graphene composite material as a composite coating. The Ni-W-P alloy itself provides a uniform corrosion-resistant barrier and high-temperature stability by forming an amorphous structure without grain boundaries. On this basis, graphene, as a barrier, can effectively bend the penetration path of the corrosion medium and provide good wear resistance. The loaded ZIF-67 encapsulated corrosion inhibitor acts as an active repair unit. Its structure can intelligently respond and release copper ion modified thiazole corrosion inhibitor molecules in a corrosive environment, preferentially adsorbing to the micro-defects of the coating to form a protective film, achieving the self-repairing function of the material. The synergistic effect of the three enhances the long-term corrosion resistance, mechanical durability, and high-temperature reliability of the electroless coating. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the application.

[0020] The sources of raw materials in the following specific examples and comparative examples are as follows: Copper: Item No. C0270039123, purchased from Nanjing Chemical Reagent Co., Ltd.; Nickel: Item No. C0180010231, purchased from Nanjing Chemical Reagent Co., Ltd.; Silicon: Item No. C0580159323, purchased from Nanjing Chemical Reagent Co., Ltd.; Chromium: Item No. C0070019235, purchased from Nanjing Chemical Reagent Co., Ltd.; Phosphorus: Item No. KA727934, purchased from Shanghai Jetseike Biological Technology Co., Ltd.; Titanium boride: Item No. PA08692, purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; Graphene: Item No. 1268698, purchased from Shanghai Haohong Biological Medicine Technology Co., Ltd.; γ-methacryloyloxypropyl trimethoxysilane: Item No. S15030, purchased from Shanghai Yuanye Biological Technology Co., Ltd.; Tris(hydroxymethyl)aminomethane: Item No. S16001, purchased from Shanghai Yuanye Biological Technology Co., Ltd.; 2-mercaptobenzothiazole: Item No. S30373, purchased from Shanghai Yuanye Biological Technology Co., Ltd.; Copper nitrate trihydrate: Item No. 93-2939, purchased from Beijing Bailingwei Technology Co., Ltd.; Cobalt nitrate hexahydrate: item number C0080530075, purchased from Nanjing Chemical Reagent Co., Ltd. 2-methylimidazole: item number M104839, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Sodium carbonate, sodium hydroxide, sodium citrate, nickel sulfate, sodium tungstate, sodium hypophosphite, sodium acetate, ammonium chloride, methanol, anhydrous ethanol, isopropanol, hydrochloric acid and hydrofluoric acid are all analytically pure.

[0021] Example 1: A high-stability semiconductor lead frame and a preparation method thereof, comprising the following steps: Step 1: Put 96.39% copper, 1.30% nickel, 0.50% silicon, 0.80% chromium, 0.01% phosphorus and 1% modified titanium boride together in a ball mill at a speed of 650 r / min, and ball mill for 1 h to obtain a mixed powder; Step 2: Put the mixed powder into a mold and cold-press at a pressure of 400 MPa to obtain a green body; Step 3: After sintering treatment at 800 ℃ for 2 h and solid solution treatment at 850 ℃ for 2 h and water quenching, a composite block is obtained; Step 4: The composite block is cold-rolled into a 0.1 mm strip at 200 ℃, and aged at 400 ℃ for 2 h to obtain a composite material; Step 5: The composite material is formed by stamping to obtain a semi-finished product of the high-stability semiconductor lead frame; Step 6: Put the semi-finished product of the high-stability semiconductor lead frame into a lye (4 g of sodium carbonate, 1 g of sodium hydroxide and 200 mL of deionized water are mixed), heat in a 70 ℃ water bath for 15 min, take out and ultrasonic clean in deionized water for 1 min, take out and ultrasonic treat in a 10% hydrochloric acid solution for 2 min, ultrasonic clean in deionized water for 1 min, and finally put into a 5% hydrofluoric acid solution and heat in a 70 ℃ water bath for 2 min to obtain the semi-finished product of the high-stability semiconductor lead frame after activation; Step 7: Dissolve 3.5 g of sodium citrate, 2 g of nickel sulfate, 3.5 g of sodium tungstate, 2.5 g of sodium hypophosphite, 2 g of sodium acetate and 0.1 g of graphene composite material in 100 mL of ultrapure water in sequence, ultrasonic stir for 30 min, add 1 mol / L sodium hydroxide solution to adjust the pH value of the solution to 8.0 to obtain a chemical plating solution; Put the semi-finished product of the high-stability semiconductor lead frame after activation into the chemical plating solution, and ultrasonic stir at 83 ℃ and a current density of 4 A / dm 2 After 30 min, take out and ultrasonic clean in deionized water for 30 s, and dry to obtain a finished product of the high-stability semiconductor lead frame; The preparation steps of the modified titanium boride are as follows: Mix 12 mL of isopropyl alcohol with 2 mL of deionized water, stir until uniform, add 0.24 mL of γ-methacryloxypropyltrimethoxysilane drop by drop, then continue stirring for 1 h to allow it to hydrolyze completely, to obtain a silane coupling agent solution; add 8 g of titanium boride, stir until mixed uniformly, to obtain a mixture; the mixture is initially dried at 80°C, then heated to 120°C for thorough drying, ground to obtain modified titanium boride; The preparation steps of the graphene composite material are as follows: S1: 3.95 g of tris-hydroxymethyl aminomethane is dissolved in 13 mL of deionized water, diluted to 25 mL with deionized water, and the pH is adjusted to 8.7 with ammonium chloride to prepare a buffer solution. At 20°C, 69 mg of 2-mercaptobenzothiazole and 50 mg of copper nitrate trihydrate are added to the buffer solution, and stirred for 30 min to obtain a thiazole-containing corrosion inhibitor precursor modified with copper ions; S2: 0.25 g of cobalt nitrate hexahydrate is dissolved in 25 mL of methanol to obtain a cobalt nitrate hexahydrate solution; 1 g of 2-methylimidazole is dissolved in 25 mL of methanol to obtain a 2-methylimidazole solution; the thiazole-containing corrosion inhibitor precursor modified with copper ions is quickly added to the cobalt nitrate hexahydrate solution, stirred for 5 min, and then the 2-methylimidazole solution is quickly added, and stirring is continued for 5 min to obtain a suspension; the suspension is transferred to a polytetrafluoroethylene-lined high-pressure reaction kettle, and reacted at 150°C for 22 h; the product is centrifuged at 10,000 rpm for 10 min, washed with ethanol 3 times, dried at 60°C for 22 h, and ground to obtain a zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite; S3: 0.3 g of graphene is dispersed in 50 mL of methanol and ultrasonically treated for 2 h to obtain a uniform graphene colloidal solution; the graphene colloidal solution and the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite are mixed and magnetically stirred at 20°C for 22 h, then the product is washed with methanol 3 times, the solid is collected, and dried in a 80°C drying oven for 22 h to obtain a graphene composite material.

[0022] Example 2: A high-stability semiconductor lead frame and a preparation method thereof, comprising the following steps: Step 1: 95.07% copper, 1.70% nickel, 0.70% silicon, 1.00% chromium, 0.03% phosphorus, and 1.5% modified titanium boride are placed in a ball mill at a rotation speed of 750 r / min, and ball-milled for 1.5 h to obtain a mixed powder; Step 2: The mixed powder is loaded into a mold and cold-pressed at a pressure of 500 MPa to obtain a green body; Step 3: The green body is subjected to sintering treatment at 830°C for 2.5 h, then subjected to solid solution treatment at 900°C for 2.5 h and water quenching, to obtain a composite block. Step 4: The composite block is cold-rolled into a 0.2mm strip at 250°C, and aged at 440°C for 2.5h to obtain a composite material; Step 5: The composite material is formed into a semi-finished product of a high-stability semiconductor lead frame by stamping; Step 6: The semi-finished product of the high-stability semiconductor lead frame is placed in an alkali solution (4g of sodium carbonate, 1g of sodium hydroxide and 200mL of deionized water are mixed), heated in a water bath at 73°C for 17min, then taken out and ultrasonically cleaned in deionized water for 1.5min, taken out and ultrasonically treated in a 10% hydrochloric acid solution for 3min, then ultrasonically cleaned in deionized water for 1.5min, and finally placed in a 5% hydrofluoric acid solution and heated in a water bath at 73°C for 3min to obtain an activated semi-finished product of the high-stability semiconductor lead frame; Step 7: 7g of sodium citrate, 4g of nickel sulfate, 7g of sodium tungstate, 5g of sodium hypophosphite, 4g of sodium acetate and 0.2g of graphene composite material are sequentially added to 200mL of ultrapure water and dissolved and ultrasonically stirred for 33min, 1mol / L of sodium hydroxide solution is added to adjust the pH value of the solution to 8.1, and a chemical plating solution is obtained; the activated semi-finished product of the high-stability semiconductor lead frame is placed in the chemical plating solution and subjected to electroless plating at 85°C and a current density of 5A / dm 2 After ultrasonic stirring for 33min, the product is taken out and ultrasonically cleaned in deionized water for 45s, dried, and the finished product of the high-stability semiconductor lead frame is obtained; The preparation steps of the modified titanium boride are as follows: 12mL of isopropyl alcohol and 2mL of deionized water are mixed and stirred until uniform, 0.24mL of γ-methacryloxypropyltrimethoxysilane is added dropwise, and then continuous stirring is performed for 1.5h to fully hydrolyze it, to obtain a silane coupling agent solution; 8g of titanium boride is added and stirred until mixed uniformly to obtain a mixture; the mixture is initially dried at 83°C, then heated to 123°C for thorough drying, and then ground to obtain modified titanium boride; The preparation steps of the graphene composite material are as follows: S1: 3.95g of tris-hydroxymethyl aminomethane is dissolved in 13mL of deionized water, diluted to 25mL with deionized water, and the pH is adjusted to 8.8 with ammonium chloride to obtain a buffer solution; 69mg of 2-mercaptobenzothiazole and 50mg of copper nitrate trihydrate are added to the buffer solution at 23°C, and stirred for 33min to obtain a thiazole-containing inhibitor precursor modified with copper ions; S2: 0.25 g of cobalt nitrate hexahydrate was dissolved in 25 mL of methanol to obtain a cobalt nitrate hexahydrate solution; 1 g of 2-methylimidazole was dissolved in 25 mL of methanol to obtain a 2-methylimidazole solution; the copper ion modified thiazole-containing corrosion inhibitor precursor was quickly added to the cobalt nitrate hexahydrate solution, stirred for 7 min, and then the 2-methylimidazole solution was quickly added, and stirring was continued for 7 min to obtain a suspension; the suspension was transferred to a polytetrafluoroethylene-lined high-pressure reaction kettle, and reacted at 160°C for 24 h; the product was centrifuged at 10500 rpm for 11 min, washed with ethanol 4 times, and dried at 63°C for 24 h; after grinding, the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite was obtained; S3: 0.3 g of graphene was dispersed in 50 mL of methanol and ultrasonically treated for 2.5 h to obtain a uniform graphene colloidal solution; the graphene colloidal solution and the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite were mixed and magnetically stirred at 23°C for 24 h; then the product was washed with methanol 4 times, the solid was collected, and dried in a drying oven at 83°C for 24 h to prepare a graphene composite material.

[0023] Example 3: A high-stability semiconductor lead frame and a preparation method thereof, comprising the following steps: Step 1: 93.65% copper, 2.10% nickel, 1.00% silicon, 1.20% chromium, 0.05% phosphorus, and 2% modified titanium boride were placed in a ball mill at a rotation speed of 850 r / min, and ball-milled for 2 h to obtain a mixed powder; Step 2: The mixed powder was loaded into a mold and cold-pressed at a pressure of 600 MPa to obtain a green body; Step 3: The green body was subjected to sintering treatment at 850°C for 3 h, and then subjected to solid solution treatment at 1000°C for 3 h and water quenching to obtain a composite block; Step 4: The composite block was cold-rolled into a 0.3 mm strip at 300°C, and then subjected to aging treatment at 480°C for 3 h to obtain a composite material; Step 5: The composite material was formed by stamping to obtain a semi-finished product of the high-stability semiconductor lead frame; Step 6: The semi-finished product of the high-stability semiconductor lead frame was placed in an alkali solution (4 g of sodium carbonate, 1 g of sodium hydroxide, and 200 mL of deionized water were mixed), heated in a water bath at 75°C for 20 min, then taken out and ultrasonically cleaned in deionized water for 2 min, then placed in a hydrofluoric acid solution with a mass concentration of 5% and heated in a water bath at 75°C for 4 min to obtain an activated semi-finished product of the high-stability semiconductor lead frame; Step 7: 14 g of sodium citrate, 8 g of nickel sulfate, 14 g of sodium tungstate, 10 g of sodium hypophosphite, 8 g of sodium acetate and 0.4 g of graphene composite were sequentially added into 400 mL of ultrapure water for dissolution and ultrasonic stirring for 35 min, 1 mol / L sodium hydroxide solution was added to adjust the pH value of the solution to 8.2, and a chemical plating solution was obtained; the activated high-stability semiconductor lead frame semi-finished product was placed in the chemical plating solution at 87°C and a current density of 6 A / dm 2 After ultrasonic stirring for 35 min, it was taken out, ultrasonically cleaned in deionized water for 60 s, dried, and the finished high-stability semiconductor lead frame was obtained; The preparation steps of the modified titanium boride are as follows: 12 mL of isopropyl alcohol and 2 mL of deionized water were mixed and stirred until uniform, 0.24 mL of γ-methacryloxypropyltrimethoxysilane was added dropwise, and then continuous stirring was performed for 2 h to fully hydrolyze it, to obtain a silane coupling agent solution; 8 g of titanium boride was added and stirred until uniformly mixed to obtain a mixture; the mixture was initially dried at 85°C, then heated to 125°C for thorough drying, ground, and the modified titanium boride was obtained; The preparation steps of the graphene composite are as follows: S1: 3.95 g of tris-hydroxymethyl aminomethane was dissolved in 13 mL of deionized water, made up to 25 mL with deionized water, and the pH was adjusted to 8.9 with ammonium chloride to prepare a buffer solution. At 25°C, 69 mg of 2-mercaptobenzothiazole and 50 mg of copper nitrate trihydrate were added to the buffer solution, stirred for 35 min, and a copper ion modified thiazole-containing corrosion inhibitor precursor was obtained; S2: 0.25 g of cobalt nitrate hexahydrate was dissolved in 25 mL of methanol to obtain a cobalt nitrate hexahydrate solution; 1 g of 2-methyl imidazole was dissolved in 25 mL of methanol to obtain a 2-methyl imidazole solution; the copper ion modified thiazole-containing corrosion inhibitor precursor was quickly added to the cobalt nitrate hexahydrate solution, stirred for 8 min, and then the 2-methyl imidazole solution was quickly added, and stirring was continued for 8 min to obtain a suspension; the suspension was transferred to a polytetrafluoroethylene-lined high-pressure reaction kettle, reacted at 170°C for 26 h, centrifuged at 11000 rpm for 12 min, washed with ethanol 5 times, dried at 65°C for 26 h, and ground to obtain a zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite; S3: 0.3 g of graphene was dispersed in 50 mL of methanol and ultrasonically treated for 3 h to obtain a uniform graphene colloidal solution; the graphene colloidal solution and the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite were mixed and magnetically stirred at 25°C for 26 h, then the product was washed with methanol 5 times, the solid was collected, and dried in a 85°C drying oven for 26 h to obtain a graphene composite.

[0024] Comparative Example 1: Compared with Example 3, no modified titanium boride is added; Step 1: 95.65% copper, 2.10% nickel, 1.00% silicon, 1.20% chromium and 0.05% phosphorus were put into a ball mill at a speed of 850 r / min by mass percentage, and ball-milled for 2 h to obtain a mixed powder; Step 2: The mixed powder was loaded into a mold, and a green body was obtained by cold pressing at a pressure of 600 MPa; Step 3: After sintering treatment of the green body at 850℃ for 3h, solid solution treatment at 1000℃ for 3h and water quenching, a composite block was obtained; Step 4: The composite block was cold-rolled into a 0.3mm strip at 300℃, and aged at 480℃ for 3h to obtain a composite material; Step 5: The composite material was formed into a semi-finished product of a high-stability semiconductor lead frame by stamping; Step 6: The semi-finished product of the high-stability semiconductor lead frame was placed in an alkali solution (4g of sodium carbonate, 1g of sodium hydroxide and 200mL of deionized water were mixed), heated in a water bath at 75℃ for 20min, then taken out and ultrasonically cleaned in deionized water for 2min, then taken out and ultrasonically treated in a 10% hydrochloric acid solution for 4min, then ultrasonically cleaned in deionized water for 2min, and finally placed in a 5% hydrofluoric acid solution and heated in a water bath at 75℃ for 4min to obtain an activated semi-finished product of the high-stability semiconductor lead frame; Step 7: 14g of sodium citrate, 8g of nickel sulfate, 14g of sodium tungstate, 10g of sodium hypophosphite, 8g of sodium acetate and 0.4g of graphene composite material were sequentially added to 400mL of ultrapure water and dissolved by ultrasonic stirring for 35min, 1mol / L of sodium hydroxide solution was added to adjust the pH value of the solution to 8.2, and a chemical plating solution was obtained; the activated semi-finished product of the high-stability semiconductor lead frame was placed in the chemical plating solution and subjected to electroless plating at 87℃ and a current density of 6A / dm 2 After ultrasonic stirring for 35min, it was taken out and ultrasonically cleaned in deionized water for 60s, and then dried to obtain a finished product of the high-stability semiconductor lead frame; The preparation steps of the graphene composite material are as follows: S1: 3.95g of tris-hydroxymethyl aminomethane was dissolved in 13mL of deionized water, diluted to 25mL with deionized water, and the pH was adjusted to 8.9 with ammonium chloride to obtain a buffer solution; 69mg of 2-mercaptobenzothiazole and 50mg of copper nitrate trihydrate were added to the buffer solution at 25℃, and stirred for 35min to obtain a thiazole-containing corrosion inhibitor precursor modified with copper ions; S2: 0.25 g of cobalt nitrate hexahydrate was dissolved in 25 mL of methanol to obtain a cobalt nitrate hexahydrate solution; 1 g of 2-methylimidazole was dissolved in 25 mL of methanol to obtain a 2-methylimidazole solution; the copper ion modified thiazole-containing corrosion inhibitor precursor was quickly added to the cobalt nitrate hexahydrate solution, stirred for 8 min, and then the 2-methylimidazole solution was quickly added, and stirring was continued for 8 min to obtain a suspension; the suspension was transferred to a polytetrafluoroethylene-lined high-pressure reaction kettle, and reacted at 170°C for 26 h; the product was centrifuged at 11000 rpm for 12 min, washed with ethanol 5 times, and dried at 65°C for 26 h; after grinding, the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite was obtained; S3: 0.3 g of graphene was dispersed in 50 mL of methanol and ultrasonically treated for 3 h to obtain a uniform graphene colloidal solution; the graphene colloidal solution and the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole corrosion inhibitor composite were mixed and magnetically stirred at 25°C for 26 h; then the product was washed with methanol 5 times, the solid was collected, and dried in a drying oven at 85°C for 26 h to prepare a graphene composite material.

[0025] Comparative Example 2: Compared with Example 3, step 6 was omitted; Step 1: 93.65% copper, 2.10% nickel, 1.00% silicon, 1.20% chromium, 0.05% phosphorus, and 2% modified titanium boride were placed in a ball mill at a rotation speed of 850 r / min, and ball-milled for 2 h to obtain a mixed powder; Step 2: The mixed powder was loaded into a mold and cold-pressed at a pressure of 600 MPa to obtain a green body; Step 3: The green body was subjected to sintering treatment at 850°C for 3 h, then subjected to solid solution treatment at 1000°C for 3 h and water quenching, to obtain a composite block; Step 4: The composite block was cold-rolled into a 0.3 mm strip at 300°C, and then subjected to aging treatment at 480°C for 3 h to obtain a composite material; Step 5: The composite material was formed by stamping to obtain a semi-finished product of a high-stability semiconductor lead frame; Step 6: 14 g of sodium citrate, 8 g of nickel sulfate, 14 g of sodium tungstate, 10 g of sodium hypophosphite, 8 g of sodium acetate, and 0.4 g of graphene composite material were sequentially added to 400 mL of ultrapure water and dissolved by ultrasonic stirring for 35 min; 1 mol / L sodium hydroxide solution was added to adjust the pH value of the solution to 8.2 to obtain a chemical plating solution; the semi-finished product of the high-stability semiconductor lead frame was placed in the chemical plating solution and subjected to ultrasonic stirring at 87°C and a current density of 6 A / dm 2 After 35 min of ultrasonic stirring, it was taken out, ultrasonically cleaned in deionized water for 60 s, and dried to obtain a finished product of a high-stability semiconductor lead frame; The preparation steps of the modified titanium boride are as follows: 12 mL of isopropyl alcohol and 2 mL of deionized water are mixed and stirred until uniform, 0.24 mL of γ-methacryloxypropyltrimethoxysilane is added dropwise, and then continuous stirring is carried out for 2 h to allow sufficient hydrolysis, to obtain a silane coupling agent solution; 8 g of titanium boride is added and stirred until uniformly mixed to obtain a mixture; the mixture is initially dried at 85°C, and then heated to 125°C for complete drying, and then ground to obtain modified titanium boride; The preparation steps of the graphene composite material are as follows: S1: 3.95 g of tris-hydroxymethyl aminomethane is dissolved in 13 mL of deionized water, diluted to 25 mL with deionized water, and the pH is adjusted to 8.9 with ammonium chloride to prepare a buffer solution; 69 mg of 2-mercaptobenzothiazole and 50 mg of copper nitrate trihydrate are added to the buffer solution at 25°C, and stirred for 35 min to obtain a thiazole-containing inhibitor precursor modified with copper ions; S2: 0.25 g of cobalt nitrate hexahydrate is dissolved in 25 mL of methanol to obtain a cobalt nitrate hexahydrate solution; 1 g of 2-methylimidazole is dissolved in 25 mL of methanol to obtain a 2-methylimidazole solution; the thiazole-containing inhibitor precursor modified with copper ions is quickly added to the cobalt nitrate hexahydrate solution, stirred for 8 min, and then the 2-methylimidazole solution is quickly added, and stirring is continued for 8 min to obtain a suspension; the suspension is transferred to a polytetrafluoroethylene-lined high-pressure reaction kettle, and reacted at 170°C for 26 h; the product is centrifuged at 11000 rpm for 12 min, washed with ethanol 5 times, dried at 65°C for 26 h, and then ground to obtain a zeolite imidazolate framework-67 encapsulated copper ion modified thiazole inhibitor composite; S3: 0.3 g of graphene is dispersed in 50 mL of methanol, and ultrasonically treated for 3 h to obtain a uniform graphene colloidal solution; the graphene colloidal solution and the zeolite imidazolate framework-67 encapsulated copper ion modified thiazole inhibitor composite are mixed, and magnetically stirred at 25°C for 26 h; then the product is washed with methanol 5 times, and the solid is collected and dried in a 85°C drying oven for 26 h to obtain a graphene composite material.

[0026] Comparative Example 3: Compared with Example 3, no graphene composite material is added to the electroless plating solution; Step 1: 93.65% copper, 2.10% nickel, 1.00% silicon, 1.20% chromium, 0.05% phosphorus, and 2% modified titanium boride are placed in a ball mill at a rotation speed of 850 r / min, and ball-milled for 2 h to obtain a mixed powder; Step 2: The mixed powder is loaded into a mold, and a green body is obtained by cold pressing at a pressure of 600 MPa; Step 3: After sintering treatment at 850°C for 3h and solid solution treatment at 1000°C for 3h and water quenching, the green body is obtained as a composite block; Step 4: The composite block is cold-rolled into a 0.3mm strip at 300°C, and then aged at 480°C for 3h to obtain a composite material; Step 5: The composite material is formed by stamping to obtain a semi-finished product of a high-stability semiconductor lead frame; Step 6: The semi-finished product of the high-stability semiconductor lead frame is placed in an alkali solution (4g of sodium carbonate, 1g of sodium hydroxide and 200mL of deionized water are mixed), heated in a water bath at 75°C for 20min, then taken out and ultrasonically cleaned in deionized water for 2min, then taken out and ultrasonically treated in a 10% hydrochloric acid solution for 4min, then ultrasonically cleaned in deionized water for 2min, and finally placed in a 5% hydrofluoric acid solution and heated in a water bath at 75°C for 4min to obtain an activated semi-finished product of the high-stability semiconductor lead frame; Step 7: 14g of sodium citrate, 8g of nickel sulfate, 14g of sodium tungstate, 10g of sodium hypophosphite and 8g of sodium acetate are sequentially added to 400mL of ultrapure water and dissolved by ultrasonic stirring for 35min, and then 1mol / L of sodium hydroxide solution is added to adjust the pH value of the solution to 8.2 to obtain a chemical plating solution; the activated semi-finished product of the high-stability semiconductor lead frame is placed in the chemical plating solution and subjected to electroplating at 87°C and a current density of 6A / dm 2 After ultrasonic stirring for 35min, the product is taken out, ultrasonically cleaned in deionized water for 60s, dried, and then obtained as a finished product of a high-stability semiconductor lead frame; The preparation steps of the modified titanium boride are as follows: 12mL of isopropyl alcohol and 2mL of deionized water are mixed and stirred until uniform, 0.24mL of γ-methacryloyloxypropyltrimethoxysilane is added dropwise, and then continuous stirring is performed for 2h to fully hydrolyze to obtain a silane coupling agent solution; 8g of titanium boride is added and stirred until uniformly mixed to obtain a mixture; the mixture is initially dried at 85°C, and then heated to 125°C for thorough drying, and then ground to obtain modified titanium boride.

[0027] Experiment: Take the high-stability semiconductor lead frames prepared in Examples 1-3 and Comparative Examples 1-3, prepare test samples, and detect their properties and record the detection results: Tensile strength test: according to GB / T 228.1-2021 standard, test environment 25°C, sample size 80mm long, 20mm wide, thickness 0.2mm, test machine strain rate 0.00025s -1 ; Conductivity test: according to GB / T 32791-2016 standard, in the test environment of 20℃, using eddy current conductivity instrument with frequency set at 120 kHz, the conductivity of the lead frame substrate with thickness of 0.2 mm and the semiconductor lead frame with surface plating layer of 20 μm of the lead frame substrate was tested; Anti-oxidation test: the sample (lead frame substrate thickness of 0.2 mm, surface plating layer of 20 μm) was heated at 300℃ for 1 h, and the thickness of the surface oxidation layer was indirectly measured by energy spectrometer; Anti-corrosion test: after the sample (lead frame substrate thickness of 0.2 mm, surface plating layer of 20 μm) was soaked in 4% sodium chloride solution for 25 days, whether corrosion points appeared on the surface of the sample was observed; All test results are shown in Table 1.

[0028] Table 1

[0029] From the data in Table 1, compared with Examples 1-3, Comparative Example 1 did not add modified titanium boride, so the tensile strength and conductivity of the lead frame prepared by Comparative Example 1 were decreased. Compared with Examples 1-3, Comparative Example 2 removed step 6, i.e. did not perform oil removal acidification and other activation treatment on the lead frame, resulting in that the plating layer was not tightly combined with the lead frame, the compactness of the plating layer was reduced, the surface oxidation layer was thickened in the anti-oxidation test, the surface was rough and corrosion points appeared in the anti-corrosion test. Compared with Examples 1-3, the tensile strength and conductivity of Comparative Example 3 were significantly decreased, the surface oxidation layer was thickened, the surface was rough and corrosion points appeared, indicating that the graphene composite material added in the application can improve the mechanical properties, electrical properties, anti-oxidation and corrosion resistance of the high-stability semiconductor lead frame.

[0030] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments, and the application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered as exemplary and non-limiting, and the scope of the application is defined by the appended claims rather than the foregoing description, and all changes falling within the meaning and range of equivalent elements of the claims are intended to be embraced in the application.

Claims

1. A method for fabricating a high-stability semiconductor lead frame, characterized in that: Includes the following steps: Step 1: Ball mill copper, nickel, silicon, chromium, phosphorus and modified titanium boride together to obtain a mixed powder; Step 2: The mixed powder is loaded into a mold and cold-pressed to obtain a green body; Step 3: After sintering, the green blank is subjected to solution treatment and then water quenching to obtain a composite block; Step 4: Cold roll the composite block into strip, and perform aging treatment to obtain the composite material; Step 5: The composite material is stamped to obtain a semi-finished product of a high-stability semiconductor lead frame; Step 6: After washing the semi-finished high-stability semiconductor lead frame in an alkaline solution, take it out and ultrasonically clean it in deionized water. Then, take it out and ultrasonically treat it in a hydrochloric acid solution, ultrasonically clean it in deionized water, and finally acid wash and activate it in a hydrofluoric acid solution to obtain the activated high-stability semiconductor lead frame semi-finished product. Step 7: Add sodium citrate, nickel sulfate, sodium tungstate, sodium hypophosphite, sodium acetate, and graphene composite material sequentially to ultrapure water for dissolution and ultrasonic stirring. Add sodium hydroxide solution to adjust the pH of the solution to 8.0~8.2 to obtain a chemical plating solution. Place the activated high-stability semiconductor lead frame semi-finished product into the chemical plating solution for electroplating. After removal, ultrasonically clean it in deionized water and dry it to obtain the finished high-stability semiconductor lead frame.

2. The method for fabricating a high-stability semiconductor lead frame according to claim 1, characterized in that: The mixed powder comprises, by mass percentage, 1.30% to 2.10% nickel, 0.50% to 1.00% silicon, 0.80% to 1.20% chromium, 0.01% to 0.05% phosphorus, 1% to 2% modified titanium boride, with the balance being copper and unavoidable impurities.

3. The method for fabricating a high-stability semiconductor lead frame according to claim 1, characterized in that: The ball milling process conditions in step 1 are a rotation speed of 650~850 r / min and a time of 1~2 h; the pressure conditions for cold pressing in step 2 are 400~600 MPa; the sintering conditions in step 3 are a temperature of 800~850℃ and a time of 2~3 h, and the solution treatment conditions are a temperature of 850~1000℃ and a time of 2~3 h; the thickness of the strip in step 4 is 0.1~0.3 mm, the cold rolling process conditions are a temperature of 200~300℃, and the aging treatment conditions are a temperature of 400~480℃ and a time of 2~3 h.

4. The method for fabricating a high-stability semiconductor lead frame according to claim 1, characterized in that: In step 6, the alkaline washing conditions are: heating in a water bath at 70-75℃ for 15-20 minutes; ultrasonic cleaning with deionized water for 1-2 minutes twice; ultrasonic treatment with hydrochloric acid solution for 2-4 minutes; and activation with hydrofluoric acid solution by heating in a water bath at 70-75℃ for 2-4 minutes. In step 7, the ultrasonic stirring time is 30-35 minutes, and the electroplating conditions are: temperature 83-87℃ and current density 4-6 A / dm³. 2 The ultrasonic stirring time is 30-35 minutes, and the ultrasonic cleaning time with deionized water is 30-60 seconds.

5. The method for fabricating a high-stability semiconductor lead frame according to claim 1, characterized in that: In step 6, the alkaline solution is a mixture of sodium carbonate, sodium hydroxide, and deionized water in a mass ratio of 4:1:200, with a hydrochloric acid solution concentration of 10% and a hydrofluoric acid solution concentration of 5%. In step 7, sodium citrate, nickel sulfate, sodium tungstate, sodium hypophosphite, sodium acetate, graphene composite material, and ultrapure water are mixed in a mass ratio of 0.7:0.4:0.7:0.5:0.4:0.02:20, with a sodium hydroxide solution concentration of 1 mol / L.

6. The method for fabricating a high-stability semiconductor lead frame according to claim 1, characterized in that: The preparation steps of the modified titanium boride are as follows: Isopropanol and deionized water were mixed and stirred until homogeneous. γ-methacryloxypropyltrimethoxysilane was added dropwise and stirred continuously for 1-2 hours to obtain a silane coupling agent solution. Titanium boride was added and stirred until homogeneous to obtain a mixture. The mixture was initially dried at 80-85°C and then heated to 120-125°C for further drying. After grinding, modified titanium boride was obtained.

7. The method for fabricating a high-stability semiconductor lead frame according to claim 6, characterized in that: The isopropanol and deionized water are mixed at a mass ratio of 6:1, and the mass of γ-methacryloyloxypropyltrimethoxysilane is 3% of the mass of titanium boride.

8. The method for fabricating a high-stability semiconductor lead frame according to claim 1, characterized in that: The preparation steps of the graphene composite material are as follows: S1: Dissolve tris(hydroxymethyl)aminomethane in deionized water and adjust the pH to 8.7-8.9 with ammonium chloride to prepare a buffer solution. Add 2-mercaptobenzothiazole and copper nitrate trihydrate to the buffer solution at 20-25℃ and stir for 30-35 min to obtain a copper ion-modified thiazole-containing corrosion inhibitor precursor. S2: Dissolve cobalt nitrate hexahydrate in methanol to obtain a cobalt nitrate hexahydrate solution; dissolve 2-methylimidazole in methanol to obtain a 2-methylimidazole solution; add the copper ion-modified thiazole-containing corrosion inhibitor precursor to the cobalt nitrate hexahydrate solution, stir for 5-8 min, then add the 2-methylimidazole solution, and continue stirring for 5-8 min to obtain a suspension; After reacting the suspension at 150-170℃ for 22-26h, centrifuge, wash with ethanol 3-5 times, dry at 60-65℃ for 22-26h, and grind to obtain the copper ion modified thiazole corrosion inhibitor complex encapsulated by zeolite imidazole ester skeleton-67. S3: Weigh graphene, disperse it in methanol, and sonicate it for 2-3 hours to obtain a uniform graphene colloidal solution; mix the graphene colloidal solution with a copper ion modified thiazole corrosion inhibitor complex encapsulated by zeolite imidazole ester framework-67, stir magnetically at 20-25℃ for 22-26 hours, then wash with methanol 3-5 times, and dry at 80-85℃ for 22-26 hours to obtain the graphene composite material.

9. The method for fabricating a high-stability semiconductor lead frame according to claim 8, characterized in that: The buffer solution in S1 has a concentration of 1.30 mol / L, and 2-mercaptobenzothiazole and copper nitrate trihydrate are mixed in a molar ratio of 2:1; the cobalt nitrate hexahydrate and methanol in S2 are mixed in a mass ratio of 1:100, and 2-methylimidazole and methanol are mixed in a mass ratio of 1:25; the graphene and methanol in S3 are mixed in a mass ratio of 3:

500.

10. A high-stability semiconductor lead frame prepared by the preparation method according to any one of claims 1-9.

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