Surface-oxidized color aluminum wire and its preparation method and application

Abstract

The application discloses surface antioxidation type color aluminum wire and a preparation method and application thereof, relates to the technical field of electronic packaging materials, and uses high-purity aluminum as a processing raw material, obtains aluminum wire through smelting, crystallization, traction, drawing and annealing processes, and carries out cleaning on the aluminum wire to remove oil stains, dust and oxide skins on the surface of the aluminum wire, then carries out surface antioxidation treatment on the aluminum wire by using an antioxidation coating, and the antioxidation performance of the aluminum wire is significantly improved, the problem that conventional aluminum wire is easily oxidized in air and the use performance is affected is solved, and then the use effect and service life of the aluminum wire as a bonding lead wire during electronic packaging are optimized.

Description

Technical fields:

[0001] This invention relates to the field of electronic packaging materials technology, specifically to a surface-antioxidant colored aluminum wire, its preparation method, and its application. Background technology:

[0002] Wire bonding is a technique that uses fine metal wires and leverages heat, pressure, and ultrasonic energy to bond metal leads tightly to substrate pads, enabling electrical interconnection and data exchange between chips and substrates. Under ideal controlled conditions, electron sharing or atomic diffusion occurs between the leads and the substrate, resulting in atomic-level bonding between the two metals. Wire bonding is used to introduce and derive electrical connections from core components and is widely applied in the packaging of discrete semiconductor devices and integrated circuits.

[0003] Based on basic materials, the bonding wires commonly used in the market currently fall into four main categories: bonding alloy wire, bonding silver wire, bonding copper wire, and bonding aluminum wire. In terms of cost, bonding aluminum wire is more advantageous. However, ordinary aluminum wire is prone to surface oxidation upon contact with air, which not only affects its conductivity but also its physical properties. This can easily lead to wire collapse and breakage during electronic packaging, causing significant production losses. Summary of the Invention:

[0004] The technical problem to be solved by the present invention is to provide a method for preparing surface-antioxidant colored aluminum wire. By processing an antioxidant coating, the surface of the aluminum wire has excellent antioxidant properties, preventing air from causing oxidation and corrosion of the aluminum wire, while also giving the aluminum wire a rich variety of appearance colors.

[0005] The technical problem to be solved by this invention is achieved by the following technical solution:

[0006] One objective of this invention is to provide a method for preparing surface-antioxidant colored aluminum wire, comprising the following steps:

[0007] (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is diverted to a crystallization furnace. After the molten aluminum solidifies, it is drawn into aluminum rods by a traction machine.

[0008] (2) The aluminum rod is drawn and annealed multiple times to obtain aluminum wire;

[0009] (3) Perform final annealing on the aluminum wire;

[0010] (4) Clean and dry the annealed aluminum wire;

[0011] (5) Apply an anti-oxidation coating evenly to the surface of the aluminum wire using a coating machine, and obtain a surface-anti-oxidation colored aluminum wire after curing.

[0012] Preferably, the intermediate annealing temperature is 100–400°C, and the time is 12–36 hours. Intermediate annealing refers to an inter-process annealing procedure performed to eliminate the deformation strengthening effect of the workpiece, improve its plasticity, and facilitate subsequent processes.

[0013] Preferably, the final annealing temperature is 80–150°C, and the time is 48–72 hours. The purpose of the final annealing is to reduce hardness and residual stress, stabilize dimensions, refine grains, and eliminate structural defects.

[0014] Preferably, the diameter of the aluminum wire is 0.03 to 0.06 mm.

[0015] Preferably, the thickness of the antioxidant coating is 20–50 μm. The appropriate antioxidant coating thickness is determined based on actual requirements.

[0016] Preferably, the antioxidant coating comprises the following components in parts by weight: 100 parts epoxy resin, 15-25 parts silicon nitride powder, 10-20 parts nano-alumina, 15-25 parts curing agent, 5-15 parts pigment, 0-5 parts curing accelerator, and 0.5-5 parts defoamer. The silicon nitride powder and nano-alumina act as fillers, improving the coating's density, toughness, wear resistance, and high-temperature oxidation resistance. The curing accelerator may or may not be added, depending on the actual curing conditions.

[0017] Preferably, the epoxy resin is a bisphenol A type epoxy resin.

[0018] Preferably, the curing agent is one or more of aliphatic amines, cyclic amines, aromatic amines, polyether amines, and polyamides. The curing agent reacts chemically with the epoxy resin to form a network three-dimensional polymer. Different curing temperatures and curing times are set for different curing agents.

[0019] Preferably, the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30). The function of the curing accelerator is to accelerate the curing reaction or lower the curing temperature.

[0020] Preferably, the defoamer is a silicone defoamer. The function of the silicone defoamer is to eliminate foam formed during the coating production process.

[0021] Preferably, the pigment is an organic pigment. Compared to inorganic pigments, organic pigments have better compatibility with epoxy resins, which can improve color uniformity.

[0022] The second objective of this invention is to provide a surface-antioxidant colored aluminum wire obtained by the aforementioned preparation method.

[0023] The third objective of this invention is to provide the aforementioned surface-antioxidant colored aluminum wire as a bonding wire for use in electronic packaging, including integrated circuits, semiconductor devices, LED lights, and other fields.

[0024] The fourth objective of this invention is to provide a method for preparing an acrylamide silane-modified epoxy resin, which replaces the epoxy resin in the aforementioned antioxidant coating, thereby further improving the antioxidant performance of the coating.

[0025] The preparation method of the propylene aminosilane modified epoxy resin is as follows: first, the epoxy resin and catalyst are mixed evenly, then 1,1,1-trimethyl-N-2-propylenepropylaminosilane and initiator are added, and the mixture is heated to react, thereby obtaining the propylene aminosilane modified epoxy resin.

[0026] Preferably, the initiator is one or more of azobisisobutyronitrile and azobisisoheptanenitrile. Other types of initiators besides azo initiators, such as organic peroxide initiators, may also be used.

[0027] Preferably, the catalyst is one or more of triphenylphosphine and palladium di(triphenylphosphine)acetate. Irradiation technology can also be used to shorten the reaction time and accelerate the reaction rate.

[0028] Preferably, the mass ratio of the epoxy resin, 1,1,1-trimethyl-N-2-propenylaminosilane, initiator, and catalyst is (80-100):(15-30):(0.5-1):(0.05-0.1).

[0029] 1,1,1-Trimethyl-N-2-propenylpropylaminosilane, CAS No.: 10519-97-8.

[0030] The beneficial effects of this invention are as follows: This invention uses high-purity aluminum as the processing raw material, and obtains aluminum wire through smelting, crystallization, traction, drawing and annealing processes. The aluminum wire is then cleaned to remove oil, dust and oxide scale from its surface. Then, an anti-oxidation coating is used to treat the surface of the aluminum wire for anti-oxidation, which significantly improves the anti-oxidation performance of the aluminum wire. This solves the problem that conventional aluminum wire is easily oxidized in the air, which affects its performance. In this way, the performance and service life of aluminum wire as a bonding wire in electronic packaging are optimized. Detailed implementation method:

[0031] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0032] The following descriptions of the raw materials used in the examples and comparative examples are as follows:

[0033] High-purity aluminum has a purity of 99.99%;

[0034] The bisphenol A type epoxy resin is bisphenol A type epoxy resin E51;

[0035] The purity of the silicon nitride powder is 99.9%, and the particle size is 50-100 nm.

[0036] The purity of the nano-alumina is 99.99%, and the particle size is 20-50 nm.

[0037] The polyetheramine is BASF polyetheramine D230;

[0038] The curing accelerator is DMP-30;

[0039] The silicone defoamer is silicone defoamer BYK-024.

[0040] Example 1

[0041] 1. Preparation of Antioxidant Coatings

[0042] Component A is obtained by mixing 100 parts of bisphenol A type epoxy resin, 15 parts of silicon nitride powder, 20 parts of nano alumina, 5 parts of phthalocyanine blue and 1 part of organosilicon defoamer evenly.

[0043] Mix 20 parts of polyetheramine and 5 parts of curing accelerator evenly to obtain component B.

[0044] Mix component A and component B evenly at a weight ratio of 1:1 to obtain an antioxidant coating.

[0045] 2. Preparation of surface-antioxidant colored aluminum wire

[0046] (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is diverted to a crystallization furnace. After the molten aluminum solidifies, it is drawn into aluminum rods by a traction machine.

[0047] (2) The aluminum rod is drawn and annealed multiple times. The intermediate annealing temperature is 250℃ and the time is 24h. After two intermediate annealing processes, an aluminum wire with a diameter of 0.04mm is obtained.

[0048] (3) The aluminum wire is finally annealed at a temperature of 120°C for 60 hours.

[0049] (4) Clean and dry the annealed aluminum wire.

[0050] (5) The above-prepared antioxidant coating is uniformly coated on the surface of the aluminum wire using a coating machine. After curing (25℃ / 36h), a surface-antioxidant colored aluminum wire is obtained with a coating thickness of 32μm.

[0051] Example 2

[0052] 1. Preparation of Antioxidant Coatings

[0053] Component A is obtained by mixing 100 parts of bisphenol A type epoxy resin, 20 parts of silicon nitride powder, 15 parts of nano alumina, 5 parts of phthalocyanine red and 1 part of organosilicon defoamer evenly.

[0054] Mix 20 parts of polyetheramine and 5 parts of curing accelerator evenly to obtain component B.

[0055] Mix component A and component B evenly at a weight ratio of 1:1 to obtain an antioxidant coating.

[0056] 2. Preparation of surface-antioxidant colored aluminum wire

[0057] (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is diverted to a crystallization furnace. After the molten aluminum solidifies, it is drawn into aluminum rods by a traction machine.

[0058] (2) The aluminum rod is drawn and annealed multiple times. The intermediate annealing temperature is 300℃ and the time is 24h. After two intermediate annealing processes, an aluminum wire with a diameter of 0.05mm is obtained.

[0059] (3) The aluminum wire is finally annealed at a temperature of 110°C for 60 hours.

[0060] (4) Clean and dry the annealed aluminum wire.

[0061] (5) The above-prepared antioxidant coating is uniformly coated on the surface of the aluminum wire using a coating machine. After curing (25℃ / 36h), a surface-antioxidant colored aluminum wire is obtained with a coating thickness of 38μm.

[0062] Example 3

[0063] 1. Preparation of Antioxidant Coatings

[0064] Component A is obtained by mixing 100 parts of bisphenol A epoxy resin, 20 parts of silicon nitride powder, 15 parts of nano alumina, 5 parts of pigment violet 23 and 1 part of organosilicon defoamer evenly.

[0065] Mix 20 parts of diethylenetriamine and 5 parts of curing accelerator evenly to obtain component B.

[0066] Mix component A and component B evenly at a weight ratio of 1:1 to obtain an antioxidant coating.

[0067] 2. Preparation of surface-antioxidant colored aluminum wire

[0068] (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is diverted to a crystallization furnace. After the molten aluminum solidifies, it is drawn into aluminum rods by a traction machine.

[0069] (2) The aluminum rod is drawn and annealed multiple times. The intermediate annealing temperature is 250℃ and the time is 24h. After two intermediate annealing processes, an aluminum wire with a diameter of 0.05mm is obtained.

[0070] (3) The aluminum wire is finally annealed at a temperature of 130°C for 60 hours.

[0071] (4) Clean and dry the annealed aluminum wire.

[0072] (5) The above-prepared antioxidant coating is uniformly coated on the surface of the aluminum wire using a coating machine. After curing (25℃ / 24h), a surface-antioxidant colored aluminum wire is obtained with a coating thickness of 29μm.

[0073] Example 4

[0074] 1. Preparation of Antioxidant Coatings

[0075] 100 parts of bisphenol A type epoxy resin, 20 parts of silicon nitride powder, 15 parts of nano alumina, 5 parts of pigment red 21 and 1 part of organosilicon defoamer were mixed evenly to obtain component A.

[0076] 25 parts of diethylenetriamine were used as component B.

[0077] Mix component A and component B evenly at a weight ratio of 1:1 to obtain an antioxidant coating.

[0078] 2. Preparation of surface-antioxidant colored aluminum wire

[0079] (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is diverted to a crystallization furnace. After the molten aluminum solidifies, it is drawn into aluminum rods by a traction machine.

[0080] (2) The aluminum rod is drawn and annealed multiple times. The intermediate annealing temperature is 200℃ and the time is 24h. After two intermediate annealing processes, an aluminum wire with a diameter of 0.04mm is obtained.

[0081] (3) The aluminum wire is finally annealed at a temperature of 120°C for 60 hours.

[0082] (4) Clean and dry the annealed aluminum wire.

[0083] (5) The above-prepared antioxidant coating is uniformly coated on the surface of the aluminum wire using a coating machine. After curing (25℃ / 24h), a surface-antioxidant colored aluminum wire is obtained with a coating thickness of 35μm.

[0084] Example 5

[0085] 1. Preparation of Antioxidant Coatings

[0086] Component A is obtained by mixing 100 parts of bisphenol A epoxy resin, 25 parts of silicon nitride powder, 10 parts of nano alumina, 5 parts of pigment orange 34 and 1 part of organosilicon defoamer evenly.

[0087] Use 25 parts of polyetheramine as component B.

[0088] Mix component A and component B evenly at a weight ratio of 1:1 to obtain an antioxidant coating.

[0089] 2. Preparation of surface-antioxidant colored aluminum wire

[0090] (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is diverted to a crystallization furnace. After the molten aluminum solidifies, it is drawn into aluminum rods by a traction machine.

[0091] (2) The aluminum rod is drawn and annealed multiple times. The intermediate annealing temperature is 280℃ and the time is 24h. After two intermediate annealing processes, an aluminum wire with a diameter of 0.05mm is obtained.

[0092] (3) The aluminum wire is finally annealed at a temperature of 125°C for 60 hours.

[0093] (4) Clean and dry the annealed aluminum wire.

[0094] (5) The above-prepared antioxidant coating is uniformly coated on the surface of the aluminum wire using a coating machine. After curing (25℃ / 36h), a surface-antioxidant colored aluminum wire is obtained with a coating thickness of 30μm.

[0095] Example 6

[0096] Example 6 replaces the bisphenol A type epoxy resin in Example 5 with an acrylamide silane modified epoxy resin, while the remaining steps and conditions are the same as in Example 5.

[0097] Preparation of propylene aminosilane modified epoxy resin: First, mix 100 parts of bisphenol A type epoxy resin and 0.1 parts of triphenylphosphine evenly, then add 15 parts of 1,1,1-trimethyl-N-2-propylenepropylaminosilane and 0.5 parts of azobisisobutyronitrile, heat to 100℃ and react. Stop the reaction when the viscosity of the reaction solution no longer changes within 15 minutes to obtain propylene aminosilane modified epoxy resin.

[0098] Example 7

[0099] Example 7 replaces the bisphenol A type epoxy resin in Example 5 with an acrylamide silane modified epoxy resin, while the remaining steps and conditions are the same as in Example 5.

[0100] Preparation of propylene aminosilane modified epoxy resin: First, mix 100 parts of bisphenol A type epoxy resin and 0.1 parts of triphenylphosphine evenly, then add 30 parts of 1,1,1-trimethyl-N-2-propylenepropylaminosilane and 0.5 parts of azobisisobutyronitrile, heat to 100℃ and react. Stop the reaction when the viscosity of the reaction solution no longer changes within 15 minutes to obtain propylene aminosilane modified epoxy resin.

[0101] Example 8

[0102] Example 8 replaces the bisphenol A type epoxy resin in Example 5 with an acrylamide silane modified epoxy resin, while the remaining steps and conditions are the same as in Example 5.

[0103] Preparation of propylene aminosilane modified epoxy resin: First, mix 100 parts of bisphenol A type epoxy resin and 0.1 parts of bis(triphenylphosphine)palladium acetate evenly, then add 25 parts of 1,1,1-trimethyl-N-2-propylenepropylaminosilane and 0.5 parts of azobisisoheptanenitrile, heat to 100℃ and react. Stop the reaction when the viscosity of the reaction solution no longer changes within 15 minutes to obtain propylene aminosilane modified epoxy resin.

[0104] Compare with Example 1

[0105] In Example 8, 1,1,1-trimethyl-N-2-propenylpropylaminosilane was replaced with allyltrimethoxysilane to obtain Control Example 1.

[0106] Compare with Example 2

[0107] By replacing 1,1,1-trimethyl-N-2-propenylpropylaminosilane in the preparation of the propyleneaminosilane-modified epoxy resin in Example 8 with acrylic acid, we obtained Control Example 2.

[0108] The antioxidant properties of the silicon wire samples prepared in Examples 1-8 and Comparative Examples 1-2 were tested, and the test results are shown in Table 1.

[0109] The impact resistance strength of the sample coating was tested according to the standard GB / T 1732-2020. After the test, the sample was placed in a 120℃ oven for hot air aging for 480 hours. The impact resistance strength was tested again, and the rate of change of impact resistance strength was calculated.

[0110] Impact strength change rate = [(impact strength before heat aging - impact strength after heat aging) / impact strength before heat aging] * 100%

[0111] Table 1

[0112] Impact strength change rate (%) Example 1 14.0 Example 2 14.8 Example 3 17.6 Example 4 15.4 Example 5 16.5 Example 6 3.9 Example 7 2.1 Example 8 2.5 Compare with Example 1 8.7 Compare with Example 2 15.2

[0113] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a surface-antioxidant colored aluminum wire, characterized in that, Includes the following steps: (1) High-purity aluminum is melted into molten aluminum using a smelting furnace, and then the molten aluminum is directed to a crystallization furnace. After the molten aluminum solidifies, it is pulled into aluminum rods by a traction machine. (2) The aluminum rod is drawn and annealed multiple times to obtain aluminum wire; (3) Perform final annealing on the aluminum wire; (4) Clean and dry the annealed aluminum wire; (5) Apply an anti-oxidation coating evenly to the surface of the aluminum wire using a coating machine, and obtain a surface-anti-oxidation colored aluminum wire after curing; The antioxidant coating comprises the following components in parts by weight: 100 parts of propylene aminosilane modified epoxy resin, 15-25 parts of silicon nitride powder, 10-20 parts of nano alumina, 15-25 parts of curing agent, 5-15 parts of pigment, 0-5 parts of curing accelerator, and 0.5-5 parts of defoamer. The preparation method of the propylene aminosilane modified epoxy resin is as follows: first, the epoxy resin and the catalyst are mixed evenly, then 1,1,1-trimethyl-N-2-propylenepropylaminosilane and an initiator are added, and the reaction is carried out at a high temperature to obtain the propylene aminosilane modified epoxy resin. The initiator is one or more of azobisisobutyronitrile and azobisisoheptanenitrile; The catalyst is one or more of triphenylphosphine and palladium di(triphenylphosphine)acetate.

2. The preparation method according to claim 1, characterized in that: The intermediate annealing temperature is 100~400℃ and the time is 12~36 h; the final annealing temperature is 80~150℃ and the time is 48~72 h.

3. The preparation method according to claim 1, characterized in that: The diameter of the aluminum wire is 0.03~0.06 mm; the thickness of the anti-oxidation coating is 20~50 μm.

4. The preparation method according to claim 1, characterized in that: The curing agent is one or more of aliphatic amines, cycloaliphatic amines, aromatic amines, polyether amines, and polyamides.

5. The preparation method according to claim 1, characterized in that: The curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

6. The preparation method according to claim 1, characterized in that: The defoamer is an organosilicon defoamer; the pigment is an organic pigment.

7. Surface-antioxidant colored aluminum wire obtained by the preparation method according to any one of claims 1 to 6.

8. The application of the surface-antioxidant colored aluminum wire as a bonding wire in electronic packaging as described in claim 7.