High-reliability coarsened semiconductor lead frame and preparation method thereof

Abstract

The invention discloses a high-reliability coarsened semiconductor lead frame and a preparation method thereof, and relates to the technical field of lead frames. The method comprises the specific steps that a copper sheet is taken to be sequentially subjected to oil removal, acid pickling and water washing, a pretreated copper sheet is obtained and placed in a pre-coarsening solution to be treated, after acid pickling, the copper sheet is transferred into a coarsening solution to be treated, after acid pickling is conducted again, titanium coating is coated, and annealing, corroding, cleaning and drying are conducted; transferring the dried copper sheet into a nickel plating solution for electro-deposition to obtain a nickel layer, transferring the copper sheet into a nickel-tin plating solution for electro-deposition of a nickel-tin layer, and transferring the copper sheet into a silver plating solution for electro-deposition to obtain a silver layer after the nickel-tin electro-deposition is finished, so as to obtain the high-reliability coarsened semiconductor lead frame; wherein the titanium coating is prepared from the following raw materials in parts by mass: 10 to 20 parts of tetrabutyl titanate, 50 to 60 parts of absolute ethyl alcohol, 3 to 5 parts of urea, 0.05 to 0.1 part of copper nitrate, 0.1 to 0.3 part of cerous nitrate hexahydrate and 10 to 20 parts of glacial acetic acid.

Description

Technical Field

[0001] This invention relates to the field of lead frame technology, specifically a high-reliability roughened semiconductor lead frame and its fabrication method. Background Technology

[0002] Semiconductor leadframes are the core components of integrated circuit packaging, undertaking critical functions such as signal transmission, mechanical support, and heat dissipation between the chip and external circuits. Their reliability directly determines the lifespan and operational stability of the integrated circuit. With the increasing demands for integration density, power density, and environmental adaptability in fields such as automotive electronics, aerospace, and high-end consumer electronics, leadframes need to possess superior plating adhesion and high-temperature reliability.

[0003] Currently, semiconductor leadframes are mostly made of copper and copper alloys, and the specific manufacturing process includes steps such as degreasing, acid pickling pretreatment, surface roughening, and multi-layer electroplating. However, existing technologies still have significant shortcomings in the following aspects: First, most leadframes on the market typically use a nickel base and silver surface design. In this process, the plating solution often relies on an aqueous solution system, such as sulfate nickel plating and cyanide silver plating. The subsequent wastewater treatment costs of these plating solutions are high and do not conform to green development. Second, if there are defects such as pinholes or scratches in the electroplated layer, it will cause "crevice corrosion" or "pitting corrosion," which accelerates the erosion of the substrate, leading to lead breakage or failure of the chip-to-frame connection. Finally, there is insufficient adhesion between plating layers and between plating layers and the substrate, and poor adhesion directly leads to a decrease in product reliability. The reliability defects between plating systems ultimately lead to a decrease in product lifespan.

[0004] In summary, existing semiconductors have many shortcomings in terms of environmental protection of coating, interlayer bonding, and reliability under high temperature and high humidity environments, which cannot meet the requirements of integrated packaging circuits for high-reliability devices. Therefore, it is urgent to develop a high-reliability roughened semiconductor lead frame to meet the needs of integrated circuit development. Summary of the Invention

[0005] The purpose of this invention is to provide a high-reliability roughened semiconductor lead frame and its preparation method to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for fabricating a high-reliability roughened semiconductor lead frame includes the following fabrication steps: Step 1: Take copper sheets and degrease, pickle and wash them in sequence to obtain pretreated copper sheets. Place them in a pre-roughening solution for treatment, pickle them and then transfer them to a roughening solution for treatment. After pickling again, coat them with titanium coating, anneal, etch, clean and dry. Step 2: After the dried copper sheet is transferred to the nickel plating solution for electrodeposition to obtain a nickel layer, it is then transferred to the nickel-tin plating solution for electrodeposition to obtain a nickel-tin layer. After the nickel-tin electrodeposition is completed, it is transferred to the silver plating solution for electrodeposition to obtain a silver layer, thus obtaining a high-reliability roughened semiconductor lead frame.

[0007] Preferably, the preparation steps of the titanium coating in step 1 are as follows: Tetrabutyl titanate is mixed in anhydrous ethanol, glacial acetic acid is added and stirred to obtain solution A; urea, copper nitrate and cerium nitrate hexahydrate are poured into anhydrous ethanol, the pH is adjusted to 2~3 to obtain solution B, and solution A and solution B are mixed and stirred for 20~50 min; More preferably, the titanium coating comprises the following raw materials by weight: 10-20 parts tetrabutyl titanate, 50-60 parts anhydrous ethanol, 3-5 parts urea, 0.05-0.1 parts copper nitrate, 0.1-0.3 parts cerium nitrate hexahydrate and 10-20 parts glacial acetic acid.

[0008] Preferably, the coating thickness of the titanium coating in step 1 is 1~3μm; Preferably, the annealing process parameters in step 1 are: under an argon atmosphere, the temperature is raised to 400-500°C at a heating rate of 5-10°C / min, and held for 1-3 hours; Preferably, the corrosion in step 1 uses a ferric chloride solution; More preferably, in step 1, the temperature of the ferric chloride solution is 45~50℃, the concentration is 3~5mol / L, and the corrosion time is 10~20min; Preferably, the pre-roughening solution in step 1 comprises the following components: 20-50 g / L copper chloride and 80-100 g / L sulfuric acid, using deionized water as the solvent; Preferably, in step 1, the voltage in the pre-roughening solution is 0.3~0.4V and the temperature is 25~30℃; the pre-roughening solution is treated for 1~3 minutes. Preferably, the roughening solution in step 1 comprises the following components: 12-15 g / L copper chloride, 100-120 g / L sulfuric acid, 2-8 mg / L hydroxyethyl cellulose, 30-90 mg / L sodium tungstate, and 30-60 mg / L sodium molybdate, using deionized water as the solvent; the current density in the roughening solution is 25-30 A / dm³. 2 The temperature is 30-40℃; the treatment is carried out in the roughening solution for 2-6 seconds.

[0009] Preferably, the preparation steps of the nickel plating solution in step 2 are as follows: choline chloride and ethylene glycol are mixed and argon gas is introduced. The mixture is stirred at 70-80°C and 100-200 r / min for 1-2 hours to obtain a eutectic solvent for later use; nickel chloride hexahydrate, nickel sulfate hexahydrate and cerium nitrate hexahydrate are placed in the eutectic solvent and dissolved under a nitrogen atmosphere at 70-80°C and 5-10 r / min. Preferably, the nickel plating bath comprises the following components: nickel chloride hexahydrate at a concentration of 20-30 g / L, nickel sulfate hexahydrate at a concentration of 200-250 g / L, and cerium nitrate hexahydrate at a concentration of 4-5 g / L; the electrodeposition process parameters for nickel plating are: current density of 1-3 mA / dm³. 2 The temperature is 60~70℃; the electrodeposition time is 30~50min.

[0010] Preferably, the nickel-tin plating bath uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:(0.5~2); the concentration of tin chloride dihydrate is 100~120 g / L; and the current density in the nickel-tin plating bath is 2~3 mA / dm³. 2 The temperature is 50~70℃ and the electrodeposition time is 20~30min.

[0011] Preferably, the silver plating solution uses a eutectic solvent as the solvent and is composed of silver nitrate; the concentration of silver nitrate is 0.1~0.2 mol / L; the silver plating is performed by constant potential electrodeposition, with a potential of -0.7~-1.2V, a temperature of 60~70℃, and an electrodeposition time of 3~5 min.

[0012] A high-reliability roughened semiconductor lead frame is prepared by the above-described preparation method.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention first pre-roughens the copper sheet through electrochemical corrosion, eliminating some surface defects while reducing the current density required for subsequent roughening and improving the bonding strength between the subsequent plating layer and the copper sheet. Molybdenum and tungsten ions are added to the roughening solution as corrosion inhibitors to suppress excessive local roughening and achieve uniform surface roughness of the copper sheet. After roughening, a titanium coating is applied to the copper sheet surface. Doped titanium dioxide is then loaded onto the roughened copper sheet surface using a sol-gel method, followed by annealing to achieve mechanical anchoring between the titanium dioxide and the roughened copper sheet. Simultaneously, N, Cu, and Ce elements are doped to optimize conductivity. While improving electrical properties, the number of active sites on the TiO2 surface increases, thereby increasing the initial nucleation site density on the copper sheet surface, shortening the distance from cluster diffusion to active sites, accelerating the crystallization step of adsorbed atoms, and further promoting the accelerated deposition and accumulation growth of nickel ions around TiO2 particles, thus enhancing interlayer bonding. The addition of rare earth cerium to the electrodeposited nickel layer refines the nickel layer grains and improves the coating uniformity. Subsequently, nickel-tin plating and constant potential silver plating are performed sequentially, all using low eutectic solvent plating solutions, achieving a synergistic improvement between environmental protection and performance, and enhancing the compatibility between the nickel and silver plating layers. Detailed Implementation

[0014] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] In the experiment, the copper sheet thickness was 2 mm; degreasing was performed using a 50 g / L sodium hydroxide solution; pickling was performed using a 10% sulfuric acid solution. Example 1: This example provides a method for fabricating a high-reliability roughened semiconductor lead frame, specifically including the following steps: Step 1: Take copper sheets and sequentially perform degreasing, pickling, and water washing to obtain pretreated copper sheets. Place them in a 25℃ pre-roughening solution for 1 minute, then pickle and transfer them to a 30℃ roughening solution for 2 seconds. The pre-roughening solution contains the following components: 20 g / L copper chloride and 80 g / L sulfuric acid, using deionized water as the solvent; the voltage in the pre-roughening solution is 0.3V. The roughening solution contains the following components: 12 g / L copper chloride, 100 g / L sulfuric acid, 2 mg / L hydroxyethyl cellulose, 30 mg / L sodium tungstate, and 30 mg / L sodium molybdate, using deionized water as the solvent; the current density in the roughening solution is 25 A / dm³. 2 ; Step 2: According to the mass ratio, take 10 parts of tetrabutyl titanate and mix them with 40 parts of anhydrous ethanol. Add 10 parts of glacial acetic acid and stir to obtain solution A. Add 3 parts of urea, 0.05 parts of copper nitrate and 0.1 parts of cerium nitrate hexahydrate to 20 parts of anhydrous ethanol and adjust the pH to 2 to obtain solution B. Mix solution A and solution B and stir for 40 min to prepare titanium coating. After acid washing, coat the roughened copper sheet with titanium coating to a thickness of 1 μm. Transfer it to a muffle furnace, introduce argon gas and heat it to 450℃ at a heating rate of 6℃ / min. Hold it at this temperature for 1 h. After cooling, place it in a 3 mol / L ferric chloride solution for 10 min for corrosion, then clean and dry. Step 3: Transfer the dried copper sheet into a nickel plating bath at 60℃, using a current density of 1 mA / dm². 2 After electrodeposition for 30 minutes to obtain a nickel layer, the electrodepositer was transferred to a nickel-tin plating bath at 60°C and plated at a current density of 2 mA / dm². 2 The electrodeposition time was 20 min for nickel-tin plating. After the nickel-tin deposition was completed, the sample was transferred to a silver plating bath at 60℃ for silver plating. The electrodeposition was carried out using a constant potential of -0.75V for 3 min to obtain a silver layer, which is sample 1. The preparation steps of the eutectic solvent are as follows: choline chloride and ethylene glycol are mixed at a molar ratio of 1:2 and argon gas is introduced. The mixture is stirred at 200 r / min for 1.5 h at 70 °C to obtain the eutectic solvent for later use. The preparation steps of the nickel plating solution in step 3 are as follows: 20 g / L nickel chloride hexahydrate, 200 g / L nickel sulfate hexahydrate and 4 g / L cerium nitrate hexahydrate are placed in a eutectic solvent and dissolved by stirring at 70 °C and 6 r / min under a nitrogen atmosphere; The nickel-tin plating solution uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:0.5; the concentration of tin chloride dihydrate is 100 g / L. The silver plating solution uses a eutectic solvent as the solvent and adds silver nitrate; the concentration of silver nitrate is 0.1 mol / L.

[0016] Example 2: This example provides a method for fabricating a high-reliability roughened semiconductor lead frame, specifically including the following steps: Step 1: Take copper sheets and sequentially perform degreasing, pickling, and water washing to obtain pretreated copper sheets. Place them in a 30℃ pre-roughening solution for 2 minutes, then pickle and transfer them to a 35℃ roughening solution for 4 seconds. The pre-roughening solution contains the following components: 30 g / L copper chloride and 100 g / L sulfuric acid, using deionized water as the solvent; the voltage in the pre-roughening solution is 0.3V. The roughening solution contains the following components: 15 g / L copper chloride, 100 g / L sulfuric acid, 5 mg / L hydroxyethyl cellulose, 40 mg / L sodium tungstate, and 50 mg / L sodium molybdate, using deionized water as the solvent; the current density in the roughening solution is 25 A / dm³. 2 ; Step 2: According to the mass ratio, take 12 parts of tetrabutyl titanate and mix them in 40 parts of anhydrous ethanol. Add 12 parts of glacial acetic acid and stir to obtain solution A. Add 3 parts of urea, 0.08 parts of copper nitrate and 0.1 parts of cerium nitrate hexahydrate to 20 parts of anhydrous ethanol and adjust the pH to 2 to obtain solution B. Mix solution A and solution B and stir for 40 min to prepare titanium coating. After acid washing, coat the roughened copper sheet with titanium coating to a thickness of 3 μm. Transfer it to a muffle furnace, introduce argon gas and heat it to 450℃ at a heating rate of 6℃ / min. Hold it at this temperature for 1 h. After cooling, place it in a 3 mol / L ferric chloride solution for 10 min for corrosion, then clean and dry. Step 3: Transfer the dried copper sheet into a nickel plating bath at 60℃, using a current density of 1 mA / dm². 2 After electrodeposition for 30 minutes to obtain a nickel layer, the electrodepositer was transferred to a nickel-tin plating bath at 60°C and plated at a current density of 2 mA / dm². 2 The electrodeposition time was 20 min for nickel-tin plating. After the nickel-tin deposition was completed, the sample was transferred to a silver plating bath at 60℃ for silver plating. The electrodeposition was carried out using a constant potential of -0.75V for 3 min to obtain a silver layer, which is sample 2. The preparation steps of the eutectic solvent are as follows: choline chloride and ethylene glycol are mixed at a molar ratio of 1:2 and argon gas is introduced. The mixture is stirred at 200 r / min for 1.5 h at 70 °C to obtain the eutectic solvent for later use. The preparation steps of the nickel plating solution in step 3 are as follows: 20 g / L nickel chloride hexahydrate, 200 g / L nickel sulfate hexahydrate and 4 g / L cerium nitrate hexahydrate are placed in a eutectic solvent and dissolved by stirring at 70 °C and 6 r / min under a nitrogen atmosphere; The nickel-tin plating solution uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:0.5; the concentration of tin chloride dihydrate is 100 g / L. The silver plating solution uses a eutectic solvent as the solvent and adds silver nitrate; the concentration of silver nitrate is 0.1 mol / L.

[0017] Example 3: This example provides a method for fabricating a high-reliability roughened semiconductor lead frame, specifically including the following steps: Step 1: Take copper sheets and sequentially perform degreasing, pickling, and water washing to obtain pre-treated copper sheets. Place them in a 25℃ pre-roughening solution for 2 minutes, then pickle and transfer them to a 30℃ roughening solution for 4 seconds. The pre-roughening solution contains the following components: 40 g / L copper chloride and 95 g / L sulfuric acid, using deionized water as the solvent; the voltage in the pre-roughening solution is 0.4 V. The roughening solution contains the following components: 15 g / L copper chloride, 100 g / L sulfuric acid, 7 mg / L hydroxyethyl cellulose, 50 mg / L sodium tungstate, and 50 mg / L sodium molybdate, using deionized water as the solvent; the current density in the roughening solution is 25 A / dm³. 2 ; Step 2: According to the mass ratio, take 15 parts of tetrabutyl titanate and mix them in 40 parts of anhydrous ethanol. Add 15 parts of glacial acetic acid and stir to obtain solution A. Add 3 parts of urea, 0.08 parts of copper nitrate and 0.2 parts of cerium nitrate hexahydrate to 20 parts of anhydrous ethanol and adjust the pH to 2 to obtain solution B. Mix solution A and solution B and stir for 40 min to prepare titanium coating. After acid washing, coat the roughened copper sheet with titanium coating to a thickness of 3 μm. Transfer it to a muffle furnace, introduce argon gas and heat it to 450℃ at a heating rate of 10℃ / min. Hold it at this temperature for 2 h. After cooling, place it in a 3 mol / L ferric chloride solution for 15 min for corrosion, then clean and dry. Step 3: Transfer the dried copper sheet into a nickel plating bath at 70°C, using a current density of 3 mA / dm². 2 After electrodeposition for 30 minutes to obtain a nickel layer, the electrodepositer was transferred to a 70°C nickel-tin plating bath and plated at a current density of 3 mA / dm². 2The electrodeposition time was 30 min for nickel-tin plating. After the nickel-tin deposition was completed, the sample was transferred to a silver plating bath at 70℃ for silver plating. Electrodeposition was performed using a constant potential of -0.8V for 3 min to obtain a silver layer, which is sample 3. The preparation steps of the eutectic solvent are as follows: choline chloride and ethylene glycol are mixed at a molar ratio of 1:2 and argon gas is introduced. The mixture is stirred at 200 r / min for 1.5 h at 70 °C to obtain the eutectic solvent for later use. The preparation steps of the nickel plating solution in step 3 are as follows: 30 g / L nickel chloride hexahydrate, 250 g / L nickel sulfate hexahydrate and 5 g / L cerium nitrate hexahydrate are placed in a eutectic solvent and dissolved by stirring at 70 °C and 10 r / min under a nitrogen atmosphere. The nickel-tin plating solution uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:1; the concentration of tin chloride dihydrate is 120 g / L; The silver plating solution uses a eutectic solvent as the solvent and adds silver nitrate; the concentration of silver nitrate is 0.2 mol / L.

[0018] Example 4: This example provides a method for fabricating a high-reliability roughened semiconductor lead frame, specifically including the following steps: Step 1: Take copper sheets and sequentially perform degreasing, pickling, and water washing to obtain pretreated copper sheets. Place them in a 30℃ pre-roughening solution for 2 minutes, then pickle and transfer them to a 35℃ roughening solution for 4 seconds. The pre-roughening solution contains the following components: 40 g / L copper chloride and 100 g / L sulfuric acid, using deionized water as the solvent; the voltage in the pre-roughening solution is 0.4 V. The roughening solution contains the following components: 15 g / L copper chloride, 120 g / L sulfuric acid, 8 mg / L hydroxyethyl cellulose, 60 mg / L sodium tungstate, and 60 mg / L sodium molybdate, using deionized water as the solvent; the current density in the roughening solution is 30 A / dm³. 2 ; Step 2: According to the mass ratio, take 18 parts of tetrabutyl titanate and mix them with 40 parts of anhydrous ethanol. Add 18 parts of glacial acetic acid and stir to obtain solution A. Add 5 parts of urea, 0.1 parts of copper nitrate and 0.2 parts of cerium nitrate hexahydrate to 20 parts of anhydrous ethanol and adjust the pH to 2 to obtain solution B. Mix solution A and solution B and stir for 40 min to prepare titanium coating. After acid washing, coat the roughened copper sheet with titanium coating to a thickness of 3 μm. Transfer it to a muffle furnace, introduce argon gas and heat it to 450℃ at a heating rate of 10℃ / min. Hold it at this temperature for 3 h. After cooling, place it in a 3 mol / L ferric chloride solution for 10 min for corrosion, then clean and dry. Step 3: Transfer the dried copper sheet into a nickel plating bath at 70°C, using a current density of 3 mA / dm². 2After electrodeposition for 40 minutes to obtain a nickel layer, the electrodeposition process was completed by transferring the material to a 70°C nickel-tin plating bath at a current density of 3 mA / dm³. 2 The electrodeposition time was 30 min for nickel-tin plating. After the nickel-tin deposition was completed, the sample was transferred to a silver plating bath at 70℃ for silver plating. The electrodeposition was performed using a constant potential of -0.8V for 5 min to obtain a silver layer, which is sample 4. The preparation steps of the eutectic solvent are as follows: choline chloride and ethylene glycol are mixed at a molar ratio of 1:2 and argon gas is introduced. The mixture is stirred at 200 r / min for 1.5 h at 70 °C to obtain the eutectic solvent for later use. The preparation steps of the nickel plating solution in step 3 are as follows: 30 g / L nickel chloride hexahydrate, 250 g / L nickel sulfate hexahydrate and 5 g / L cerium nitrate hexahydrate are placed in a eutectic solvent and dissolved by stirring at 70 °C and 10 r / min under a nitrogen atmosphere. The nickel-tin plating solution uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:2; the concentration of tin chloride dihydrate is 120 g / L; The silver plating solution uses a eutectic solvent as the solvent and adds silver nitrate; the concentration of silver nitrate is 0.2 mol / L.

[0019] Comparative Example 1: As a control experiment for Example 4, unlike Example 4, no pre-roughening or roughening treatment was performed. The specific steps are as follows: Step 1: Take copper sheets and perform degreasing, pickling and water washing in sequence to obtain pretreated copper sheets; Step 2: According to the mass ratio, take 18 parts of tetrabutyl titanate and mix them with 40 parts of anhydrous ethanol. Add 18 parts of glacial acetic acid and stir to obtain solution A. Add 5 parts of urea, 0.1 parts of copper nitrate and 0.2 parts of cerium nitrate hexahydrate to 20 parts of anhydrous ethanol and adjust the pH to 2 to obtain solution B. Mix solution A and solution B and stir for 40 min to prepare titanium coating. After acid washing, coat the pretreated copper sheet with titanium coating to a thickness of 3 μm. Transfer it to a muffle furnace, introduce argon gas and heat it to 450℃ at a heating rate of 10℃ / min. Hold it at this temperature for 3 h. After cooling, place it in a 3 mol / L ferric chloride solution for 10 min for corrosion, then clean and dry. Step 3: Transfer the dried copper sheet into a nickel plating bath at 70°C, using a current density of 3 mA / dm². 2 After electrodeposition for 40 minutes to obtain a nickel layer, the electrodeposition process was completed by transferring the material to a 70°C nickel-tin plating bath at a current density of 3 mA / dm³. 2 The electrodeposition time was 30 min for nickel-tin plating. After the nickel-tin deposition was completed, the sample was transferred to a silver plating bath at 70℃ for silver plating. Electrodeposition was performed using a constant potential of -0.8V for 5 min to obtain a silver layer, which is sample 5. The preparation steps of the eutectic solvent are as follows: choline chloride and ethylene glycol are mixed at a molar ratio of 1:2 and argon gas is introduced. The mixture is stirred at 200 r / min for 1.5 h at 70 °C to obtain the eutectic solvent for later use. The preparation steps of the nickel plating solution in step 3 are as follows: 30 g / L nickel chloride hexahydrate, 250 g / L nickel sulfate hexahydrate and 5 g / L cerium nitrate hexahydrate are placed in a eutectic solvent and dissolved by stirring at 70 °C and 10 r / min under a nitrogen atmosphere. The nickel-tin plating solution uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:2; the concentration of tin chloride dihydrate is 120 g / L; The silver plating solution uses a eutectic solvent as the solvent and adds silver nitrate; the concentration of silver nitrate is 0.2 mol / L.

[0020] Comparative Example 2: As a control experiment for Example 4, the difference is that titanium slurry coating and annealing were not performed; the specific steps are as follows: Step 1: Take copper sheets and sequentially perform degreasing, pickling, and water washing to obtain pretreated copper sheets. Place them in a 30℃ pre-roughening solution for 2 minutes, then pickle and transfer them to a 35℃ roughening solution for 4 seconds. The pre-roughening solution contains the following components: 40 g / L copper chloride and 100 g / L sulfuric acid, using deionized water as the solvent; the voltage in the pre-roughening solution is 0.4 V. The roughening solution contains the following components: 15 g / L copper chloride, 120 g / L sulfuric acid, 8 mg / L hydroxyethyl cellulose, 60 mg / L sodium tungstate, and 60 mg / L sodium molybdate, using deionized water as the solvent; the current density in the roughening solution is 30 A / dm³. 2 ; Step 2: After etching the roughened copper sheet in a 3 mol / L ferric chloride solution for 10 minutes, clean and dry it. Step 3: Transfer the dried copper sheet into a nickel plating bath at 70°C, using a current density of 3 mA / dm². 2 After electrodeposition for 40 minutes to obtain a nickel layer, the electrodeposition process was completed by transferring the material to a 70°C nickel-tin plating bath at a current density of 3 mA / dm³. 2 The electrodeposition time was 30 min for nickel-tin plating. After the nickel-tin deposition was completed, the sample was transferred to a silver plating bath at 70℃ for silver plating. The electrodeposition was performed using a constant potential of -0.8V for 5 min to obtain a silver layer, which is sample 6. The preparation steps of the eutectic solvent are as follows: choline chloride and ethylene glycol are mixed at a molar ratio of 1:2 and argon gas is introduced. The mixture is stirred at 200 r / min for 1.5 h at 70 °C to obtain the eutectic solvent for later use. The preparation steps of the nickel plating solution in step 3 are as follows: 30 g / L nickel chloride hexahydrate, 250 g / L nickel sulfate hexahydrate and 5 g / L cerium nitrate hexahydrate are placed in a eutectic solvent and dissolved by stirring at 70 °C and 10 r / min under a nitrogen atmosphere. The nickel-tin plating solution uses a eutectic solvent as the solvent and is composed of tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1:2; the concentration of tin chloride dihydrate is 120 g / L; The silver plating solution uses a eutectic solvent as the solvent and adds silver nitrate; the concentration of silver nitrate is 0.2 mol / L.

[0021] Testing and Experiment 1. The first-level MSL test was performed on samples 1-6 prepared in Examples 1-4 and Comparative Examples 1-2. The test conditions were: baking at 125℃ for 24h → treatment at 85℃ / 85%RH for 168h → reflow soldering 3 times → confirming the delamination. If delamination occurred, it was recorded as unqualified, and if there was no delamination, it was recorded as qualified. The test results are recorded in Table 1. 2. Referring to GB / T15878, samples 1-6 prepared in Examples 1-4 and Comparative Examples 1-2 were baked at 250°C for 30 minutes and copper peeling tests were performed. The test results are recorded in Table 1.

[0022] Table 1

[0023] Conclusion: As can be seen from the above test data, Examples 1-4 all passed the reliability test and copper peel test; however, Comparative Example 1, as the control experiment of Example 4, did not undergo pre-roughening and roughening, and Comparative Example 2, as the control experiment of Example 4, did not undergo titanium coating and subsequent annealing, which both had a certain impact on the subsequent reliability test and copper peel test.

[0024] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of manufacturing a high-reliability roughened semiconductor leadframe, comprising: providing a semiconductor leadframe; and roughening the semiconductor leadframe to form a plurality of roughened surfaces. The preparation method comprises the following steps: Step 1: copper sheets are sequentially subjected to oil removal, pickling and water washing to obtain pretreated copper sheets, which are treated in a pre-roughening solution, subjected to pickling, transferred into a roughening solution for treatment, subjected to pickling again, coated with a titanium coating, annealed, corroded, cleaned and dried; Step 2: after the dried copper sheets are transferred into a nickel plating solution to electrodeposit a nickel layer, the nickel layer is transferred into a nickel-tin plating solution to electrodeposit a nickel-tin layer, and after the electrodepositing of the nickel-tin layer is completed, the nickel-tin layer is transferred into a silver plating solution to electrodeposit a silver layer, thereby obtaining a high-reliability roughened semiconductor lead frame.

2. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of a mechanical method, a chemical method, a physical method, and a combination thereof. The preparation steps of the titanium coating in step 1 are as follows: tetrabutyl titanate is mixed in anhydrous ethanol, glacial acetic acid is added and stirred to obtain solution A; urea, copper nitrate and cerium nitrate hexahydrate are poured into anhydrous ethanol, and the pH is adjusted to 2-3 to obtain solution B, and solution A and solution B are mixed and stirred for 20-50 min; the titanium coating comprises the following raw materials in parts by mass: 10-20 parts of tetrabutyl titanate, 50-60 parts of anhydrous ethanol, 3-5 parts of urea, 0.05-0.1 parts of copper nitrate, 0.1-0.3 parts of cerium nitrate hexahydrate and 10-20 parts of glacial acetic acid.

3. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of a mechanical method, a chemical method, a physical method, and a combination thereof. The coating thickness of the titanium coating is 1-3 μm; and the process parameters for annealing in step 1 are as follows: the temperature is raised to 400-500 ℃ at a heating rate of 5-10 ℃ / min under an argon atmosphere, and the temperature is maintained for 1-3 h.

4. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of a mechanical method, a chemical method, a physical method, and a combination thereof. The corrosion in step 1 adopts a ferric chloride solution; the temperature of the ferric chloride solution is 45-50 ℃, the concentration is 3-5 mol / L; and the corrosion time is 10-20 min.

5. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of a mechanical method, a chemical method, a physical method, and a combination thereof. The pre-roughening solution in step 1 comprises the following components: deionized water as a solvent, 20-50 g / L of copper chloride and 80-100 g / L of sulfuric acid; the voltage in the pre-roughening solution is 0.3-0.4 V, and the temperature is 25-30 ℃; and the treatment time in the pre-roughening solution is 1-3 min.

6. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of: a mechanical method, a chemical method, a physical method, and a combination thereof. The roughing solution in step 1 comprises the following components: 12-15 g / L of copper chloride, 100-120 g / L of sulfuric acid, 2-8 mg / L of hydroxyethyl cellulose, 30-90 mg / L of sodium tungstate, and 30-60 mg / L of sodium molybdate, with deionized water as the solvent; the current density in the roughing solution is 25-30 A / dm 2 , and the temperature is 30-40℃; the treatment time in the roughing solution is 2-6 s.

7. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of a mechanical method, a chemical method, a physical method, and a combination thereof. The preparation step of the nickel plating solution in step 2 is as follows: mix choline chloride and ethylene glycol and pass argon gas, stir at 70-80 DEG C, 100-200 r / min for 1-2 h to obtain a eutectic solvent, and reserve; place nickel chloride hexahydrate, nickel sulfate hexahydrate and cerium nitrate hexahydrate in the eutectic solvent, and dissolve under a nitrogen atmosphere, stirring at 70-80 DEG C, 5-10 r / min; the nickel plating solution comprises the following components: the concentration of nickel chloride hexahydrate is 20-30 g / L, the concentration of nickel sulfate hexahydrate is 200-250 g / L, and the concentration of cerium nitrate hexahydrate is 4-5 g / L; the electrodeposition process parameters for nickel plating are: the current density is 1-3 mA / dm 2 , the temperature is 60-70 DEG C, and the electrodeposition time is 30-50 min.

8. The method of claim 1, wherein the roughening of the lead frame is performed by a method selected from the group consisting of: a mechanical method, a chemical method, a physical method, and a combination thereof. The nickel-tin plating solution is composed of a eutectic solvent, tin chloride dihydrate and nickel chloride hexahydrate; the molar ratio of tin chloride dihydrate to nickel chloride hexahydrate is 1: (0.5-2); the concentration of tin chloride dihydrate is 100-120 g / L; the current density of the nickel-tin plating solution is 2-3 mA / dm 2 , the temperature is 50-70 ℃, and the electrodeposition time is 20-30 min.

9. A method for fabricating a high-reliability roughened semiconductor lead frame according to claim 1, characterized in that, The silver plating solution is composed of a eutectic solvent as a solvent and silver nitrate; the concentration of the silver nitrate is 0.1-0.2 mol / L; the silver plating is electrodepositing by constant potential, the potential is -0.7 to -1.2 V, the temperature is 60-70 ℃, and the electrodepositing time is 3-5 min.

10. A high-reliability roughened semiconductor leadframe, characterized by, The high-reliability roughened semiconductor lead frame is prepared by the preparation method in any one of claims 1-9.

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