A wire cleaning device, method and use

Abstract

The present application relates to wire cleaning technical field, especially to a kind of wire cleaning device, method and application.A kind of wire cleaning device of the present application, including charged dust collection unit;The charged dust collection unit includes corona wire and tubular dust collection anode plate, and the corona wire is located at the axial center position of the tubular dust collection anode plate.The wire cleaning device provided by the present application passes through charged dust collection unit, and the micro-particles on the surface of wire are charged by using current auxiliary, and the micro-particles on the surface of wire are removed by electrostatic precipitation, to avoid secondary pollution caused by the contact between micro-particles and wire;And, the device is small and convenient, can be integrated in wire drawing or annealing equipment rear end, low in cost, and small in footprint.

Description

Technical Field

[0001] The present invention relates to the technical field of wire cleaning, and in particular to a wire cleaning device, method and application. Background Art

[0002] The surface cleanliness of bond wires significantly impacts both their inherent performance and bonding performance. Traditionally, wire preparation processes apply drawing and annealing fluids during the drawing and annealing process to lubricate the wire and prevent sticking. However, metal ions and airborne dust from the drawing and annealing fluids can remain on the wire surface during the preparation process. These surface particles can become embedded within the wire or remain on the surface during further drawing or annealing and rewinding, deteriorating the wire's mechanical and bonding properties.

[0003] Currently, cleaning bond wires typically involves installing a cleaning tank at the back end of the wire drawing equipment for bubble cleaning or using an additional ultrasonic cleaning device. However, both methods involve immersing the bond wires in water, leaving traces of cleaning residue in the water and easily causing secondary contamination. Furthermore, using ultrasonic cleaning after final annealing can cause the wires to stick, limiting their use. Furthermore, specialized ultrasonic cleaning equipment requires a dedicated pay-off and take-up system and tensioning system, which is expensive and requires significant space.

[0004] In view of this, this invention is proposed. Summary of the Invention

[0005] The first purpose of the present invention is to provide a wire cleaning device, which uses a charged dust collection unit to assist in charging the particles on the surface of the wire with the help of electric current, and removes the particles on the surface of the wire through electrostatic dust removal, thereby avoiding secondary pollution caused by contact between the particles and the wire; moreover, the device is small and convenient, and can be integrated into the back end of the drawing or annealing equipment, with low cost and small footprint.

[0006] The second object of the present invention is to provide a wire cleaning method that can effectively remove particles on the surface of the wire with high efficiency and good cleaning effect, and is particularly suitable for removing micron-sized particles.

[0007] A third object of the present invention is to provide application of the above-mentioned wire cleaning method in bonding wire cleaning.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0009] In a first aspect, the present invention provides a wire cleaning device comprising a charged dust collecting unit;

[0010] The charged dust collecting unit comprises a corona wire and a tubular dust collecting anode plate, wherein the corona wire is located at the axial center of the tubular dust collecting anode plate.

[0011] including at least one of the following features (1) to (5);

[0012] (1) The diameter of the corona wire is 0.2 to 0.3 cm;

[0013] (2) The material of the corona wire includes stainless steel;

[0014] (3) The inner radius of the tubular dust collecting anode plate is 1 to 2 cm;

[0015] (4) The length of the tubular dust collecting anode plate is 100 to 300 mm;

[0016] (5) The tubular dust collecting anode plate is made of stainless steel or aluminum alloy.

[0017] Furthermore, in the charged dust collecting unit, the center distance between the wire and the corona wire is 0.11 to 0.45 cm;

[0018] And / or, the voltage applied to the charged dust collecting unit is 14 to 55 kV.

[0019] Furthermore, the wire cleaning device further comprises a power supply; the corona wire is connected to the negative electrode of the power supply, and the tubular dust collecting anode plate is connected to the positive electrode of the power supply;

[0020] And / or, the wire cleaning device also includes a conveying unit; the conveying unit includes a pay-off shaft, a tension rod, a first guide wheel, a second guide wheel and a take-up shaft arranged in sequence; the charged dust collection unit is arranged between the first guide wheel and the second guide wheel.

[0021] In a second aspect, the present invention further provides a wire cleaning method, using the wire cleaning device as described above, comprising the following steps:

[0022] The wire material to be cleaned moves in a direction parallel to the corona wire and passes through the charging dust collection unit. After the particles on the surface of the wire material are charged and dust is collected, the cleaned wire material is obtained.

[0023] Furthermore, the following relationship is satisfied: Where U is the DC voltage applied between the corona wire and the tubular dust collecting anode plate by the power supply, in kV; M is the surface roughness coefficient of the wire; δ is the relative density of the gas; a is the radius of the corona wire, in cm; b is the inner radius of the tubular dust collecting anode plate, in cm.

[0024] Furthermore, the following relationship is satisfied: Where x is the center distance between the wire and the corona wire, in cm.

[0025] Furthermore, the following relationship is satisfied: l>v·(t c+t col );where l is the length of the tubular dust collecting anode plate, in m; t c is the charging time, in seconds; t col is the dust collection time, in seconds; v is the moving speed of the wire, in m / s;

[0026] Where τ is the charging time constant, in seconds; A is the van der Waals Hamaker constant between the particle and the wire; d p is the equivalent diameter of the particle, in m; q s is the saturated charge of the particle, in C; Z is the distance between the particle and the wire surface, in m; The unit is kV / cm;

[0027] Where μ is the air viscosity coefficient, in Pa·s; ε0 is the vacuum dielectric constant; and r is the center distance between the particle and the corona wire, in cm.

[0028] Furthermore, the particle size of the particles removed by the wire cleaning method satisfies the following relationship: Where A is the van der Waals Hamaker constant between the particle and the wire; Z is the distance between the particle and the wire surface, in meters; E x is the electric field strength at the wire, in kV / cm; ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the particles.

[0029] In a third aspect, the present invention further provides application of the wire cleaning method described above in bonding wire cleaning.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The wire cleaning device of the present invention uses a charged dust collection unit to assist in charging the particles on the surface of the wire with an electric current, and removes the particles on the surface of the wire through electrostatic dust removal, effectively avoiding secondary contamination caused by the contact between the particles and the wire in traditional ultrasonic cleaning.

[0032] 2. The wire cleaning device of the present invention adopts micro-electrostatic dust removal, which can effectively remove particles on the surface of the wire, has high efficiency and good cleaning effect, and is particularly suitable for removing micron-sized particles.

[0033] 3. Compared with traditional ultrasonic cleaning devices, the wire cleaning device of the present invention is more compact, low-cost, and occupies less space. It can be integrated after wire drawing or after the annealing machine. As a final cleaning method, it avoids problems such as wire sticking and abnormal wire pay-off. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 Schematic diagram of the structure of the wire cleaning device of the present invention.

[0036] Figure 2 Schematic diagram of corona discharge and charging of the present invention.

[0037] Figure 3 It is the spatial electric field intensity curve of the charged dust collecting unit of the present invention.

[0038] Figure 4 This is a picture of particles adsorbed on the bonding wire surface of the present invention.

[0039] Figure 5 This is the particle dust collection driving speed curve of the present invention.

[0040] Figure 6 This is the particle dust collection time curve of the present invention.

[0041] Figure 7 This is a surface morphology of the uncleaned bonding wire of the present invention.

[0042] Figure 8 This is a surface morphology of the bonding wire after ultrasonic cleaning of the present invention.

[0043] Figure 9 This is a surface morphology of the bonding wire after cleaning according to Example 1 of the present invention.

[0044] Figure 10 This is the spatial electric field intensity curve of the charged dust collecting unit of Example 2 of the present invention.

[0045] Figure 11 This is the spatial electric field intensity curve of the charged dust collecting unit of Example 3 of the present invention.

[0046] Reference numerals:

[0047] 11-corona wire; 12-tubular dust collecting anode plate; 2-power supply; 3-wire; 41-pay-off shaft; 42-tension wheel; 43-first guide wheel; 44-second guide wheel; 45-take-up shaft; 46-tension rod; 47-servo motor. DETAILED DESCRIPTION

[0048] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. Those who do not specify specific conditions in the embodiments are carried out according to normal conditions or the conditions recommended by the manufacturer. Those whose reagents or instruments are not specified by the manufacturer are conventional products that can be purchased commercially.

[0049] The following is a detailed description of a wire cleaning device, method and application of the present invention.

[0050] See also Figure 1 , in some embodiments of the present invention, a wire cleaning device is provided, comprising a charged dust collecting unit;

[0051] The charged dust collecting unit includes a corona wire 11 and a tubular dust collecting anode plate 12 , wherein the corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12 .

[0052] The wire cleaning device of the present invention charges the particles on the surface of the wire with the help of electric current, removes the particles on the surface of the wire through electrostatic dust removal, and avoids secondary pollution caused by contact between the particles and the wire; moreover, the device is compact and convenient, and can be integrated into the back end of the wire drawing or annealing equipment, with low cost and small footprint.

[0053] The wire cleaning device of the present invention adopts a micro-electrostatic field to remove dust, thereby effectively avoiding secondary pollution caused by the contact between particles and wires in traditional ultrasonic cleaning.

[0054] The wire cleaning device of the present invention adopts micro-electrostatic dust removal, which can effectively remove particles on the surface of the wire, has high efficiency and good cleaning effect, and is particularly suitable for removing micron-sized particles.

[0055] The wire cleaning device of the present invention is more compact, low-cost, and occupies less space than traditional ultrasonic cleaning devices. It can be integrated after wire drawing or after the annealing machine. As a final cleaning method, it avoids problems such as wire sticking and abnormal wire pay-off.

[0056] The wire cleaning device of the present invention is used to clean the wire. In the device, the particles on the surface of the wire are charged and dust is collected. During the charging stage, the gas molecules undergo corona discharge under the action of the high-voltage electric field, thereby generating a large number of free electrons and positive ions, that is, gas ionization. The positive ions are immediately attracted by the corona wire and lose their charge. The free electrons move toward the tubular dust-collecting anode plate under the action of the electric field, filling the space between the two poles. When the wire containing particles enters this area, the free electrons meet the particles, attach to the particles, and make the particles negatively charged. After the charging stage, the dust collection stage begins. During the dust collection process, the electric field force on the particles is greater than the van der Waals force. The particles break away from the adsorption of the wire and move toward the tubular dust-collecting anode plate, thereby effectively removing the particles on the surface of the wire.

[0057] In some embodiments of the present invention, the corona wire 11 is coaxial with the tubular dust collecting anode plate 12 .

[0058] In some embodiments of the present invention, the diameter of the corona wire 11 is 0.2 to 0.3 cm. Typically, but not limiting, the diameter of the corona wire 11 can be 0.2 cm, 0.25 cm, 0.3 cm, or any combination thereof. These diameters make the corona wire compact and easily integrated into wire drawing, annealing, and other equipment.

[0059] In some embodiments of the present invention, the corona wire 11 is made of stainless steel.

[0060] In some embodiments of the present invention, the cross-section of the corona wire 11 is circular.

[0061] In some embodiments of the present invention, the length of the corona wire 11 is greater than or equal to the length of the tubular dust collecting anode plate 12, which can ensure that the electric field strength in the length direction of the tubular dust collecting anode plate is consistent and is easy to install.

[0062] In some embodiments of the present invention, the inner radius of the tubular dust collecting anode plate 12 is 1 to 2 cm; typically but not restrictively, for example, the thickness of the tubular dust collecting anode plate 12 can be 1 cm, 1.5 cm, 2 cm or a range of any two thereof.

[0063] The inner radius of the tubular dust collecting anode plate affects the voltage that needs to be applied, the spatial electric field strength, the dust collection time and the length of the tubular dust collecting anode plate.

[0064] In some embodiments of the present invention, the length of the tubular dust collecting anode plate 12 is 100 to 300 mm; typically but not restrictively, for example, the length of the tubular dust collecting anode plate 12 can be 100 mm, 150 mm, 200 mm, 250 mm, 300 mm or a range of any two thereof.

[0065] The length of the tubular dust collecting anode plate adopts the above dimensions, which is conducive to ensuring the dust collection efficiency and is convenient for installation and equipment integration.

[0066] In some embodiments of the present invention, the tubular dust collecting anode plate 12 is made of stainless steel or aluminum alloy.

[0067] In some embodiments of the present invention, in the charged dust collecting unit, the center distance between the wire and the corona wire 11 is 0.11 to 0.45 cm; typically but not limitatively, for example, in the charged dust collecting unit, the center distance between the wire and the corona wire 11 can be 0.11 cm, 0.15 cm, 0.20 cm, 0.25 cm, 0.30 cm, 0.35 cm, 0.40 cm, 0.45 cm or a range of any two thereof.

[0068] In some embodiments of the present invention, the voltage applied to the charged dust collecting unit is 14 to 55 kV; typically but not limitatively, for example, the voltage applied to the charged dust collecting unit can be 14 kV, 20 kV, 25 kV, 30 kV, 35 kV, 40 kV, 45 kV, 50 kV, 55 kV or a range of any two thereof.

[0069] In some embodiments of the present invention, the tubular dust collecting anode plate 12 is fixed to the corona wire 11 by screws and nuts; this allows for easy disassembly, washing, and drying, avoiding secondary contamination and allowing for reuse. In some embodiments of the present invention, the corona wire 11 is connected to the negative electrode of the power supply 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power supply 2.

[0070] In some embodiments of the present invention, the tubular dust collecting anode plate 12 is grounded.

[0071] The corona wire of the invention is connected to the negative electrode of the power supply, has high breakdown voltage, strong stability and higher dust removal efficiency for fine particles.

[0072] In some embodiments of the present invention, the power supply 2 includes a DC / DC direct current boost module.

[0073] The DC / DC direct current boost module outputs high-voltage direct current. Specifically, it generates low-voltage pulses through high-frequency oscillation, then boosts the voltage to a predetermined voltage value through a pulse transformer, and then obtains high-voltage direct current through pulse rectification to supply the charged dust collection unit.

[0074] In some embodiments of the present invention, the wire cleaning device also includes a conveying unit; the conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 arranged in sequence; the charged dust collection unit is arranged between the first guide wheel 43 and the second guide wheel 44; preferably, a tension rod 46 is provided on the tension wheel 42.

[0075] In some embodiments of the present application, the conveying unit further comprises a servo motor 47 connected to the pay-off shaft 41 and the take-up shaft 45, respectively.

[0076] In some embodiments of the present application, the pay-off shaft 41 and the take-up shaft 45 comprise an insulating material.

[0077] In some embodiments of the present application, the wire cleaning device further comprises a support fixing module for fixing the electrostatic dust collecting unit.

[0078] In some embodiments of the present application, a wire cleaning method is provided, which uses the above-mentioned wire cleaning device and comprises the following steps:

[0079] The wire to be cleaned moves in a direction parallel to the corona wire 11 and passes through the electrostatic dust collecting unit, and after the particles on the surface of the wire are electrostatically charged and collected, the cleaned wire is obtained.

[0080] In some embodiments of the present application, the input voltage of the input end of the power supply 2 is 12-24V; personnel safety can be ensured.

[0081] In some embodiments of the present application, the direct current voltage U applied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 satisfies the following relationship:

[0082] In the formula, U is the direct current voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; M is the surface roughness coefficient of the corona wire; δ is the relative density of the gas; a is the radius of the corona wire, in cm; and b is the inner radius of the tubular dust collecting anode plate, in cm.

[0083] According to the Pick empirical formula, the starting electric field strength of corona is wherein E c is the starting electric field strength of corona, in kV / cm; δ is the relative density of the gas; and M is the surface roughness coefficient of the corona wire, M=1 for a smooth wire.

[0084] For example, if the radius a of the corona wire is 0.1 cm, M is 1, and δ is 1, then E c is 58 kV / cm.

[0085] The space electric field strength of the electrostatic dust collecting unit is wherein E ris the spatial electric field intensity, kV / cm; U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, kV; r is the distance between the particle and the center of the corona wire, cm; b is the inner radius of the tubular dust collecting anode plate, cm; a is the radius of the corona wire, cm; the settings of U, b and a should ensure that the electric field intensity E generated on the surface of the corona wire is a Greater than E c , causing ionization of the air near the corona wire; Right now kV.

[0086] For example, for a=0.1 cm, b=1 cm, M=1, δ=1, U>13.4 kV can meet the corona discharge requirements.

[0087] In some embodiments of the present invention, the center distance x between the wire and the corona wire 11 satisfies the following relationship:

[0088] Where x is the center distance between the wire and the corona wire, in cm; U is the DC voltage applied between the corona wire and the tubular dust collecting anode plate, in kV; δ is the relative density of the gas; M is the surface roughness coefficient of the corona wire; b is the inner radius of the tubular dust collecting anode plate, in cm; a is the radius of the corona wire, in cm.

[0089] In order to avoid the air gap between the wire and the corona wire being broken through and burning the wire, the wire should be located outside the corona zone. In order to ensure that the particles on the surface of the wire are effectively charged, the wire should be as close to the corona wire as possible. Therefore, the center distance between the wire and the corona wire is

[0090] For example, U is 25kV, and the spatial electric field strength curve of the charged dust collecting unit is as follows: Figure 3 As shown in the figure. Since the initial corona intensity is 58 kV / cm, gas ionization occurs in areas with electric field intensity greater than this value, and the electric field intensity at the surface of the corona wire reaches its highest level, about 109 kV / cm. Therefore, the corona zone is the spatial range from the surface of the corona wire to the initial corona intensity, that is, the spatial range of 0.1 to 0.19 cm from the center of the corona wire. The wire can be arranged 0.2 to 0.3 cm from the center of the corona wire, and the corresponding electric field intensity is 55 to 43 kV / cm.

[0091] See also Figure 2 During the charging process, there is an electrostatic field E in the corona region that is sufficient to partially ionize the gas. rThis electric field causes the gas molecules to undergo corona discharge under the influence of the high-voltage electric field, generating a large number of free electrons and positive ions, i.e., gas ionization. The positive ions are immediately attracted to the corona wires 11 and lose their charge. The free electrons, under the influence of the electric field, move toward the tubular dust-collecting anode plate 12, filling the space between the two electrodes. When the wire material 3 containing microparticles enters this area, the free electrons encounter the microparticles, attach to them, and negatively charge them.

[0092] In some embodiments of the present invention, the length l of the tubular dust collecting anode plate 12 satisfies the following relationship:

[0093] l>v·(t c +t col );where l is the length of the tubular dust collecting anode plate, in m; t c is the charging time, in seconds; t col is the dust collection time, in seconds; v is the moving speed of the wire, in m / s;

[0094] Where τ is the charging time constant, in seconds; A is the van der Waals Hamaker constant between the particle and the wire; d p is the equivalent diameter of the particle, in m; q s is the saturated charge of the particle, in C; Z is the distance between the particle and the wire surface, in m; The unit is kV / cm;

[0095] Where μ is the air viscosity coefficient, in Pa·s; b is the inner radius of the tubular dust collecting anode plate, in cm; a is the radius of the corona wire, in cm; ε0 is the vacuum dielectric constant; d p is the equivalent diameter of the particle, in m; U is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; x is the center distance between the wire and the corona wire, in cm; r is the distance between the particle and the center of the corona wire, in cm.

[0096] See also Figure 4 The particle size of the surface of wire materials, such as bonding wire, is typically 2 to 10 μm. After the wire enters the charged area, the particles are charged by the electric field. On the one hand, the charged particles are attracted to the surface of the wire due to the van der Waals force, and on the other hand, they are directed toward the tubular dust collecting anode plate due to the electric field force.

[0097] In some embodiments of the present invention, the particle size of the particles removed by the wire cleaning method satisfies the following relationship: Where, d pis the equivalent diameter of the particle, in m; A is the van der Waals Hamaker constant between the particle and the wire; Z is the distance between the particle and the wire surface, in m; E x is the electric field strength at the wire, in kV / cm; ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the particles.

[0098] For the adhesion of dust particles, van der Waals force plays a dominant role. Where A is the van der Waals Hamaker constant between the dust particles and the wire, which is on the order of 10 -20 J;d p is the equivalent diameter of the particle; Z is the distance between the particle and the surface of the wire. Van der Waals force usually works in the range of 0.4 to 10 nm. When Z = 0.4 nm, the van der Waals force is the largest and the particle is most stable.

[0099] Electric force F e =q p E x Among them, E x is the electric field strength at the location of the wire, kV / cm; q p is the particle charge, q p It's about time, q s is the saturation charge of the particle, C; Among them, ε r is the relative dielectric constant of the particles, usually ranging from 2 to 8, and here it is 5; ε0 is the dielectric constant of vacuum, ε0 = 8.85 × 10 -12 C 2 / N·m;d p is the equivalent diameter of the particle, m; τ is the charging time constant, s; Where N0 is the ion density, ions / m 3 ; e is the electron charge, e=1.6×10 -19 C; K is the ion mobility, m 2 / s·V;t c is the charging time, s; when t=t c When the particle charge F e =F v , the charging phase ends, then At this time, the particle charge The minimum particle size requirement F for dust collection can be achieved e =q s E x >F v ,Right now

[0100] For example, for x = 0.2 cm, a = 0.1 cm, b = 1 cm, U = 25 kV, Z = 0.4 nm, ε r =5,d pmin =1.9μm.

[0101] Under atmospheric temperature conditions, the typical distribution of N0 and K is N0 = 5 × 10 14 pcs / m 3 , K = 2.2 × 10 -4 m 2 / (s·V), then the charging time constant τ=0.002s; when time t c =τ, the particle charge is half of the saturation charge.

[0102] For example, for x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =1.9μm, U=25kV, Z=0.4nm, ε r =5, when t=t c =0.047s, the particle charge q p =1.161×10 -15 C;

[0103] For x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =3μm, U=25kV, Z=0.4nm, ε r =5, when t=t c =0.0034s, the particle charge q p =1.833×10 -15 C, at this time F e =F v .

[0104] When t>t c , F e >F v , the particles will break away from the adsorption of the wire and move toward the tubular dust collecting anode plate, and the particles enter the dust collection stage; during the dust collection process, the particles are affected by the drag force of the air and the electric field force.

[0105] Drag force F D =3πμd p ω; drag force prevents particles from flying towards the tubular dust collecting anode plate; where μ is the air viscosity coefficient, usually 17.9×10 -6 Pa·s; ω is the speed at which particles approach the tubular dust collecting anode plate, m / s; electric field force F e =q p E r , assuming that air is a Newtonian fluid, then Where m is the mass of the particle; tcol is the dust collection time; in, Very small and can be ignored. In an electric field, the speed at which charged particles approach The driving speed is related to the distance r between the particle and the center of the corona wire. The particle collection driving speed curve is as follows: Figure 5 shown.

[0106] The time required for the particles to be collected by the tubular dust collecting anode plate Particle collection time curve is as follows Figure 6 shown.

[0107] During the dust collection stage, the particles move at a certain speed v in the direction of the wire. Therefore, in order to complete the particle charging and dust collection in the charged dust collection unit, the length of the tubular dust collection anode plate l> v (t c +t col ).

[0108] For x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =1.9μm, U=25kV, t c =47ms, t col =3.97ms, for v=1.5m / s, l>0.0765m;

[0109] For x = 0.2 cm, a = 0.1 cm, b = 1 cm, d p =3μm, U=25kV, t col =2.45ms, for v=1.5m / s, l>0.0088m.

[0110] In some embodiments of the present invention, the radius a of the corona wire 11 is 0.1 to 0.15 cm; the inner radius b of the tubular dust collecting anode plate 12 is 1 to 2 cm; the applied voltage U is related to the values ​​of a and b. When b = 1 cm, U is 14 to 26 kV, and when b = 2 cm, U is 19 to 55 kV. The values ​​of a, b, and U will also affect the value of the distance x between the wire and the center of the corona wire 11, and the value range of x is 0.11 to 0.45 cm; the minimum clean dust particle size d pmin It is also affected by the values ​​of the above four key parameters, with a value range of 1.9 to 7.2 μm, indicating that micron-sized dust particles above this value can be clearly cleared; considering the values ​​of the above key parameters and the convenience of equipment integration and installation, the moving speed of the wire is controlled at 0.1 to 3 m / s; the length l of the tubular dust collecting anode plate 12 is 100 to 300 mm.

[0111] In some embodiments of the present invention, specific parameter settings in the wire cleaning method are shown in Table 1.

[0112] Table 1

[0113]

[0114] See also Figure 1 In some embodiments of the present invention, the wire ends are drawn from the payout spool 41, sequentially passing through the tension pulley 42, the first guide pulley 43, the charged dust collection unit, and the second guide pulley 44. The wire ends are then wound around the take-up spool 45, where they are attached to the take-up spool 45. Once the spools are installed and the DC power supply is turned on, the payout spool 41 and the take-up spool 45 rotate synchronously, driven by the servo motor 47. Simultaneously, the take-up spool 45 reciprocates, allowing the wire to pass through the charged dust collection system. Particles are charged in the system and, under the action of the electric field, are released from the wire surface and adsorbed onto the dust collection plate. The cleaned wire is then gradually wound around the take-up spool 45, evenly distributed. During the winding process, the tension rod 46 provides the winding tension.

[0115] In some embodiments of the present invention, the wire is appropriately tensioned during movement. For a wire with a diameter of 18 to 30 μm, the wire tension is 1.2 to 3 gf.

[0116] In some embodiments of the present invention, the wire material comprises a bonding wire.

[0117] In some embodiments of the present invention, application of the above-mentioned wire cleaning method in bonding wire cleaning is also provided.

[0118] Example 1

[0119] See also Figure 1 , the bonding wire cleaning device provided in this embodiment includes a charged dust collection unit, a power supply and a conveying unit;

[0120] The charged dust collection unit includes a corona wire 11 and a tubular dust collecting anode plate 12. The corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12. The corona wire 11 is coaxial with the tubular dust collecting anode plate 12. The radius a of the corona wire 11 is 0.1 cm, the length is 120 mm, and the material is stainless steel. The tubular dust collecting anode plate 12 has a thickness of 2 mm, an inner radius b of 1 cm, and a length l of 100 mm.

[0121] The corona wire 11 is connected to the negative electrode of the power supply 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power supply 2 and is grounded;

[0122] Power supply 2 includes a DC / DC direct current boost module;

[0123] The conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 arranged in sequence; the charged dust collecting unit is arranged between the first guide wheel 43 and the second guide wheel 44; a tension rod 46 is provided on the tension wheel 42; the pay-off shaft 41 is connected to the servo motor 47; the take-up shaft 45 is connected to the servo motor 47.

[0124] The bonding wire cleaning method provided in this embodiment uses the bonding wire cleaning device described above and includes the following steps:

[0125] The wire ends are drawn out from the pay-off reel 41, passed through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44 in sequence, and wound around the take-up reel 45 to stick the wire ends to the take-up reel 45; after the reels are installed, the DC power supply is turned on, and the pay-off reel 41 and the take-up reel 45 rotate synchronously driven by the servo motor 47. At the same time, the take-up reel 45 also reciprocates back and forth, so that the annealed bonding wire with a diameter of 18 to 30 μm moves at a moving speed (v) of 1.5 m / s under a wire tension of 1.2 to 3 gf in a direction parallel to the corona wire 11 and passes through the charged dust collection unit. After charging and collecting dust from the particles on the surface of the bonding wire, a clean bonding wire is obtained. The cleaned wire is gradually wound on the take-up reel 45 and arranged evenly.

[0126] The DC voltage (U) supplied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 is 25kV; in the charged dust collecting unit, the electric field strength on the surface of the corona wire 11 is 109kV / cm, which is higher than the initial electric field strength (E c 58kV / cm), which meets the requirements of corona discharge, thereby generating a large number of free electrons and positive ions, that is, gas ionization, and the spatial electric field intensity is as follows Figure 3 As shown;

[0127] In the charged dust collection unit, the bonding wire is parallel to the corona wire 11 and on the horizontal side of the corona wire 11. The center distance (x) between the bonding wire and the corona wire 11 is 0.2 cm. At this time, the bonding wire is located outside the corona zone to prevent the air gap between the bonding wire and the corona wire from being punctured and burning the bonding wire, while ensuring the effective charging of the particles on the bonding wire surface.

[0128] In the charged dust collection unit, the positive ions in the space are immediately attracted by the corona wire and lose their charge. The free electrons move towards the tubular dust collecting anode plate under the action of the electric field and fill the space between the two poles. When the free electrons collide with the particles on the surface of the bonding wire, they attach to the particles and make them negatively charged. Figure 3 As shown; at this time, the particles are subject to van der Waals attraction and electric field repulsion; under atmospheric temperature conditions, the typical value distribution of N0 and K is N0 = 5×10 14 pcs / m 3 , K = 2.2 × 10 -4 m 2 / (s·V), then the charging time constant τ=0.002s; when time t c =τ, the particle charge is half of the saturation charge; for x = 0.2cm, a = 0.1cm, b = 1cm, d pmin =1.9μm, U=25kV, Z=0.4nm, ε r =5, when t=t c =0.047s, the charge q p =1.161×10 -15 C, end of charging stage;

[0129] When t>t c When F e >F v The particles will break away from the bonding wire adsorption and move toward the tubular dust collecting anode plate. Particles with a diameter of 1.9μm or more will enter the dust collecting stage. During the dust collecting process, the particles are affected by the drag force of the air and the electric field force. The particle driving speed is as follows: Figure 5 As shown; for x = 0.2 cm, a = 0.1 cm, b = 1 cm, d pmin =1.9μm, U=25kV, t c =47ms, t col =3.97ms, for v=1.5m / s, l>0.0765m, therefore, l=100mm can meet the dust collection 1.9μm (d pmin ) or above particle size is required.

[0130] The bonding wire cleaning method of this embodiment can clean the bonding wire of 1.9 μm (d pmin ) and above particles can be effectively removed.

[0131] Cleaning effect:

[0132] The surface morphologies of the uncleaned bonding wire, the bonding wire after ultrasonic cleaning, and the bonding wire after cleaning of Example 1 are as follows: Figure 7 、 Figure 8 and Figure 9 As shown. Figures 7 to 9 It can be seen that the surface of the uncleaned bonding wire is covered with a large number of black particles with a particle size of 2 to 10 μm. The surface of the bonding wire after ultrasonic cleaning has a small amount of particles. The bonding wire surface after cleaning by the bonding wire cleaning method of Example 1 has no black particles, and the cleaning effect is the best.

[0133] Example 2

[0134] The bonding wire cleaning device provided in this embodiment includes a charged dust collection unit, a power supply, and a conveying unit;

[0135] The charged dust collection unit includes a corona wire 11 and a tubular dust collecting anode plate 12. The corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12. The corona wire 11 is coaxial with the tubular dust collecting anode plate 12. The radius a of the corona wire 11 is 0.15 cm, the length is 180 mm, and the material is stainless steel. The tubular dust collecting anode plate 12 has a thickness of 2 mm, an inner radius b of 2 cm, and a length l of 150 mm.

[0136] The corona wire 11 is connected to the negative electrode of the power supply 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power supply 2 and is grounded;

[0137] Power supply 2 includes a DC / DC direct current boost module;

[0138] The conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 arranged in sequence; the charged dust collecting unit is arranged between the first guide wheel 43 and the second guide wheel 44; a tension rod 46 is provided on the tension wheel 42; the pay-off shaft 41 is connected to the servo motor 47; the take-up shaft 45 is connected to the servo motor 47.

[0139] The bonding wire cleaning method provided in this embodiment uses the bonding wire cleaning device described above and includes the following steps:

[0140] The wire ends are drawn out from the pay-off reel 41, passed through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44 in sequence, and wound around the take-up reel 45 to stick the wire ends to the take-up reel 45; after the reels are installed, the DC power supply is turned on, and the pay-off reel 41 and the take-up reel 45 rotate synchronously driven by the servo motor 47. At the same time, the take-up reel 45 also reciprocates back and forth, so that the annealed bonding wire with a diameter of 18 to 30 μm moves at a moving speed (v) of 2 m / s under a wire tension of 1.2 to 3 gf in a direction parallel to the corona wire 11 and passes through the charged dust collection unit. After charging and collecting dust from the particles on the surface of the bonding wire, a clean bonding wire is obtained. The cleaned wire is gradually wound on the take-up reel 45 and arranged evenly.

[0141] The DC voltage (U) supplied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 is 22 kV; in the charged dust collecting unit, the electric field strength on the surface of the corona wire 11 is 56.6 kV / cm, which is higher than the initial electric field strength (E c 53.2kV / cm), which meets the requirements of corona discharge, thereby generating a large number of free electrons and positive ions, that is, gas ionization, and the spatial electric field intensity is as follows Figure 10 As shown;

[0142] In the charged dust collection unit, the bonding wire is parallel to the corona wire 11 and on the horizontal side of the corona wire 11. The center distance (x) between the bonding wire and the corona wire 11 is 0.17 cm. At this time, the bonding wire is located outside the corona zone, which prevents the air gap between the bonding wire and the corona wire from being punctured and burning the bonding wire, while ensuring that the particles on the bonding wire surface are effectively charged.

[0143] In the charged dust collection unit, the positive ions in the space are immediately attracted by the corona wire and lose their charge. The free electrons move towards the tubular dust collecting anode plate under the action of the electric field and fill the space between the two electrodes. When the free electrons collide with the particles on the surface of the bonding wire, they attach to the particles and make them negatively charged. For x = 0.17 cm, a = 0.1 cm, b = 2 cm, d pmin =2.4μm, U=22kV, Z=0.4nm, ε r =5, when t=t c =26.6ms, the charge q p =1.594×10 -15 C, the charging stage ends; when t>t c When F e >F v , the particles will break away from the bonding wire adsorption and move toward the tubular dust collecting anode plate. Particles with a diameter of 2.4 μm or more will enter the dust collecting stage. During the dust collecting process, the particles are affected by the drag force of the air and the electric field force. For x = 0.17 cm, a = 0.1 cm, b = 2 cm, d pmin =2.4μm, U=22kV, t c =26.6ms, t col =43.6ms, for v=2m / s, l>0.1403m, therefore, l=150mm can meet the dust collection 2.4μm (d pmin The bonding wire cleaning method of this embodiment can be used for particles with a diameter of 2.4μm (d pmin ) and above particles can be effectively removed.

[0144] Example 3

[0145] The bonding wire cleaning device provided in this embodiment includes a charged dust collection unit, a power supply, and a conveying unit;

[0146] The charged dust collection unit includes a corona wire 11 and a tubular dust collecting anode plate 12. The corona wire 11 is located at the axial center of the tubular dust collecting anode plate 12. The corona wire 11 is coaxial with the tubular dust collecting anode plate 12. The radius a of the corona wire 11 is 0.15 cm, the length is 180 mm, and the material is stainless steel. The tubular dust collecting anode plate 12 has a thickness of 2 mm, an inner radius b of 1 cm, and a length l of 150 mm.

[0147] The corona wire 11 is connected to the negative electrode of the power supply 2, and the tubular dust collecting anode plate 12 is connected to the positive electrode of the power supply 2 and is grounded;

[0148] Power supply 2 includes a DC / DC direct current boost module;

[0149] The conveying unit includes a pay-off shaft 41, a tension wheel 42, a first guide wheel 43, a second guide wheel 44 and a take-up shaft 45 arranged in sequence; the charged dust collecting unit is arranged between the first guide wheel 43 and the second guide wheel 44; a tension rod 46 is provided on the tension wheel 42; the pay-off shaft 41 is connected to the servo motor 47; the take-up shaft 45 is connected to the servo motor 47.

[0150] The bonding wire cleaning method provided in this embodiment uses the bonding wire cleaning device described above and includes the following steps:

[0151] The wire ends are drawn out from the pay-off shaft 41, passed through the tension wheel 42, the first guide wheel 43, the charged dust collection unit, the second guide wheel 44 in sequence, and wound around the take-up shaft 45 to stick the wire ends to the take-up shaft 45; after the spools are installed, the DC power supply is turned on, and the pay-off shaft 41 and the take-up shaft 45 rotate synchronously driven by the servo motor 47. At the same time, the take-up shaft 45 also reciprocates back and forth, so that the annealed bonding wire with a diameter of 18 to 30 μm moves from the pay-off shaft in a direction parallel to the corona wire 11 at a moving speed (v) of 2 m / s under a wire tension of 1.2 to 3 gf and passes through the charged dust collection unit. After charging and collecting dust on the surface of the bonding wire, the cleaned bonding wire is obtained. The cleaned wire is gradually wound on the take-up shaft 45 and arranged evenly.

[0152] The DC voltage (U) supplied by the power supply 2 between the corona wire 11 and the tubular dust collecting anode plate 12 is 16 kV; in the charged dust collecting unit, the electric field strength on the surface of the corona wire 11 is 56.2 kV / cm, which is higher than the initial electric field strength (E c 53.2kV / cm), which meets the requirements of corona discharge, thereby generating a large number of free electrons and positive ions, that is, gas ionization, and the spatial electric field intensity is as follows Figure 11 As shown;

[0153] In the charged dust collection unit, the bonding wire is parallel to the corona wire 11 and on the horizontal side of the corona wire 11. The center distance (x) between the bonding wire and the corona wire 11 is 0.16 cm. At this time, the bonding wire is located outside the corona zone, which prevents the air gap between the bonding wire and the corona wire from being broken down and burning the bonding wire, while ensuring that the particles on the bonding wire surface are effectively charged.

[0154] In the charged dust collecting unit, the positive ions in the space are immediately attracted to the corona wire and lose the charge, and the free electrons move to the direction of the tubular dust collecting anode plate under the action of the electric field, and fill the space between the two poles. When the free electrons collide with the particles on the surface of the bonding wire, the particles are attached to the particles and the particles are negatively charged. For x=0.16 cm, a=0.15 cm, b=1 cm, d pmin =2.1 μm, U=16 kV, Z=0.4 nm, ε r =5, when t=t c =42.2 ms, the charge q p =1.322×10 -15 C, the charging stage ends; when t>t c , F e >F v , the particles will escape from the adsorption of the bonding wire and move to the tubular dust collecting anode plate, and the particles with a particle size of 2.1 μm or more enter the dust collecting stage; during the dust collecting process, the particles are subjected to the air drag force and the electric field force. For x=0.16 cm, a=0.1 cm, b=2 cm, d pmin =2.1 μm, U=16 kV, t c =42.2 ms, t col =6.3 ms, for v=3 m / s, l>0.1456 m, therefore, l=150 mm can meet the dust collecting requirement of the particles with a particle size of 2.1 μm (d pmin ) or more. The bonding wire cleaning method of the embodiment can effectively remove the particles with a particle size of 2.1 μm (d pmin ) or more.

[0155] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wire cleaning method, characterized in that: The method is carried out using a wire cleaning device, wherein the wire cleaning device includes a charged dust collection unit; The charged dust collecting unit comprises a corona wire and a tubular dust collecting anode plate, wherein the corona wire is located at the axial center of the tubular dust collecting anode plate; The wire material to be cleaned moves in a direction parallel to the corona wire and passes through the charging dust collection unit, and the particles on the surface of the wire material are charged and dust is collected to obtain the cleaned wire material; The following relationship is satisfied: Where, U It is the DC voltage applied by the power supply between the corona wire and the tubular dust collecting anode plate, in kV; M is the surface roughness coefficient of the corona wire; δ is the relative density of gas; a is the radius of the corona wire, in cm; b is the inner radius of the tubular dust collecting anode plate, in cm; The following relationship is satisfied: Where, x The center distance between the wire and the corona wire, in cm.

2. The wire cleaning method according to claim 1, characterized in that: including at least one of the following features (1) to (5); (1) The diameter of the corona wire is 0.2-0.3 cm; (2) The material of the corona wire includes stainless steel; (3) The inner radius of the tubular dust collecting anode plate is 1-2 cm; (4) The length of the tubular dust collecting anode plate is 100-300 mm; (5) The tubular dust collecting anode plate is made of stainless steel or aluminum alloy.

3. The wire cleaning method according to claim 2, characterized in that: In the charged dust collecting unit, the center distance between the wire and the corona wire is 0.11~0.45cm; And / or, the voltage applied to the charged dust collecting unit is 14~55kV.

4. The wire cleaning method according to claim 3, characterized in that: The wire cleaning device further comprises a power supply; the corona wire is connected to the negative electrode of the power supply, and the tubular dust collecting anode plate is connected to the positive electrode of the power supply; And / or, the wire cleaning device also includes a conveying unit; the conveying unit includes a pay-off shaft, a tension wheel, a first guide wheel, a second guide wheel and a take-up shaft arranged in sequence; the charged dust collection unit is arranged between the first guide wheel and the second guide wheel.

5. The wire cleaning method according to claim 1, wherein: The following relationship is satisfied: Where, l is the length of the tubular dust collecting anode plate, in m; t c is the charging time, in s; t col is the dust collection time, in seconds; v is the moving speed of the wire, in m / s; Where, τ is the charging time constant, in s; A is the van der Waals Hamaker constant between the particle and the wire; d p is the equivalent diameter of the particle, in m; q s is the saturation charge of the particle, in C; Z is the distance between the particle and the wire surface, in m; , unit is kV / cm; Where, μ is the air viscosity coefficient, in Pa·s; ε 0 is the dielectric constant of vacuum; r is the distance between the particle and the center of the corona wire, in cm.

6. The wire cleaning method according to claim 5, characterized in that: The particle size of the particles removed by the wire cleaning method satisfies the following relationship: Where, A is the van der Waals Hamaker constant between the particle and the wire; Z is the distance between the particle and the wire surface, in m; , E x is the electric field strength at the wire, in kV / cm; ε 0 is the dielectric constant of vacuum, ε r is the relative dielectric constant of the particles.

7. Use of the wire cleaning method according to any one of claims 1 to 6 in bonding wire cleaning.

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