Wire welding method for broken tungsten wire, method for cutting crystalline silicon and application of wire welding method for improving chromatic aberration caused by broken wire and wire welding

Abstract

The invention relates to the technical field of crystal silicon slicing, in particular to a wire welding method for broken tungsten wires, a method for cutting crystal silicon and application of the wire welding method to improvement of chromatic aberration caused by broken wire welding. The wire welding method for the broken tungsten wire comprises the steps that when a welding spot is welded, the welding current is controlled to be 22-26 milliamperes, and the wire welding time is 10-15 seconds. According to the wire welding method for broken tungsten wires, the method for cutting crystalline silicon and the application of the wire welding method for broken tungsten wires and the method for cutting crystalline silicon in the aspect of improving chromatic aberration caused by broken wire welding, the success rate of tungsten wire welding is increased by optimizing the welding parameters of the welding wires, and then the cutting efficiency is improved. And meanwhile, by reducing the line speed of missed welding spots, tungsten filament shaking is reduced, and chromatic aberration lines are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of crystalline silicon slicing, and in particular to a wire bonding method for broken tungsten wires, a method for cutting crystalline silicon, and applications thereof in improving color difference caused by broken wire bonding. Background Art

[0002] At present, the consumption of traditional fossil energy is increasing, the energy crisis and environmental pollution are becoming more and more serious, and the world is investing more and more in the production and research and development of renewable energy. In order to achieve the "dual carbon" goal, and at the same time, solar photovoltaic power generation has the advantages of no emissions, no noise, mature application technology, safety and reliability, which has led to an increasing demand for installation and production capacity in the entire photovoltaic industry; in addition, in order to further reduce silicon costs and increase power generation efficiency, silicon wafers are gradually showing a trend of thinning, large size and thinning of tungsten wires.

[0003] Due to the special features of tungsten wire, the difficulty of wire bonding increases. Wire bonding is an indispensable process to save the yield and improve the yield in the silicon wafer manufacturing process, which has a great impact on the efficiency and yield of the entire silicon wafer production. The wire bonding efficiency determines the yield of silicon wafers. At the same time, with the continuous thinning of silicon wafers and the promotion trend of tungsten wire, wire breakage and wire breakage losses continue to increase in the entire production process, resulting in increased wire breakage losses and affecting cutting efficiency.

[0004] Based on the above situation, silicon wafer manufacturing urgently needs to develop a more efficient tungsten wire breakage processing method to improve production change efficiency, reduce wire breakage losses, and improve yield rate. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a wire bonding method for broken tungsten wires, a method for cutting crystalline silicon, and applications thereof in improving color difference caused by broken wire bonding.

[0006] Based on this, the present invention has the following technical solutions: In a first aspect, the present invention provides a wire welding method for a broken tungsten wire, comprising: when welding a welding spot, controlling the welding current to be 22-26 mA and the wire welding time to be 10-15 seconds.

[0007] According to a tungsten wire broken wire welding method provided by the present invention, cooling treatment, normalizing treatment and ignition treatment are performed in sequence after welding; the normalizing treatment time is 300-350 milliseconds, the normalizing treatment current is 12-15 mA, the ignition treatment time is 2-5 seconds, and the ignition treatment current is 12-16 mA.

[0008] According to a wire welding method for a broken tungsten wire provided by the present invention, the welding strength of the welding wire is tested after the ignition treatment, and adjustments are made according to the test results.

[0009] According to a wire welding method with a broken tungsten wire provided by the present invention, when testing the welding strength of the welding wire, if the welding point is smooth without bulges or depressions, the welding point is broken by lifting the weight, and the normalizing current is adjusted to 14-15 mA.

[0010] According to a wire welding method for a broken tungsten wire provided by the present invention, when testing the welding strength of the welding wire, if the welding point is bulging, blackening and bending, the welding current is adjusted to 22-26 mA; and the wire head top force is adjusted to 0.8-1.5 N.

[0011] In a second aspect, the present invention provides a method for cutting crystalline silicon, comprising cutting crystalline silicon using a bonding wire obtained by the bonding wire method of breaking a tungsten wire.

[0012] According to a method for cutting crystalline silicon provided by the present invention, welding wires with qualified welding strength are collected into a wire net, and welding point running begins after the wire collection is completed; the wire speed of the welding point running is controlled to be 8-12 m / s.

[0013] According to a method for cutting crystalline silicon provided by the present invention, the recovery process is modified, the table speed is first reduced to 75%~85% of the original speed, and then restored to the original table speed; the line speed is first reduced to 75%~85% of the original speed, and then restored to the original line speed.

[0014] According to a method for cutting crystalline silicon provided by the present invention, the recovery process adopts a small cycle cutting mode, which specifically includes the following steps: first supply line 495-505 meters, return line 445-455 meters; then supply line 595-605 meters, return line 545-555 meters.

[0015] In a third aspect, the present invention provides an application of the wire bonding method for a broken tungsten wire or the method for cutting crystalline silicon to improve the color difference caused by the broken wire bonding.

[0016] The invention provides a method for welding wires with broken tungsten wires, a method for cutting crystalline silicon, and their application in improving the color difference caused by broken welding wires. By optimizing the welding parameters of the welding wires, the success rate of tungsten wire welding is improved, thereby improving the cutting efficiency. At the same time, by reducing the line speed of the welding point, the jitter of the tungsten wire steel wire is reduced, and the color difference texture is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is the cut crystalline silicon obtained by the cutting method provided in Example 1 of the present invention.

[0019] Figure 2 This is the cut crystalline silicon obtained by the cutting method provided in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In a first aspect, the present invention provides a wire welding method for a broken tungsten wire. When welding a welding spot, the welding current is controlled to be 20-26 mA and the wire welding time is 10-15 seconds.

[0022] The present invention finds that, for a tungsten wire break welding method, by controlling the welding current and the welding time within the above range, the tungsten wire welding efficiency can be improved, while reducing the wire breakage loss and color difference degradation problems, and improving the yield. Specifically, the welding current within the range can ensure the welding effect of the tungsten wire welding point, and the welding time within the range can further ensure the welding quality.

[0023] During the specific implementation process, those skilled in the art can make fine adjustments within the above-mentioned current and time ranges according to the actual welding point conditions. For example, the welding current can be 22 mA, 23 mA, 24 mA, 25 mA or 26 mA, and the welding time can be 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds or 15 seconds.

[0024] According to a preferred embodiment of the present invention, cooling treatment and solidification treatment are performed in sequence after welding; the solidification treatment includes normalizing treatment and ignition treatment.

[0025] According to a preferred embodiment provided by the present invention, the cooling treatment time is 18 to 22 seconds, for example, it can be 18 seconds, 19 seconds, 20 seconds, 21 seconds or 22 seconds, and any two of the above values ​​are range values ​​of endpoint values.

[0026] According to a preferred embodiment of the present invention, the normalizing treatment time is 300-350 milliseconds, and the normalizing treatment current is 12-15 mA.

[0027] In the specific implementation process, the normalizing treatment time can be 300 milliseconds, 310 milliseconds, 320 milliseconds, 330 milliseconds, 340 milliseconds or 350 milliseconds, and any two of the above values ​​are range values ​​of endpoint values; the normalizing treatment current can be 12 mA, 13 mA, 14 mA or 15 mA, and any two of the above values ​​are range values ​​of endpoint values.

[0028] According to a preferred implementation manner provided by the present invention, and / or, the ignition treatment time is 2 to 5 seconds, and the ignition treatment current is 12 to 16 mA.

[0029] In the specific implementation process, the time of the ignition treatment can be 2 seconds, 3 seconds, 4 seconds or 5 seconds, and any two of the above values ​​are range values ​​of endpoint values; the current of the ignition treatment can be 12 mA, 13 mA, 14 mA, 15 mA or 16 mA, and any two of the above values ​​are range values ​​of endpoint values.

[0030] According to a preferred embodiment of the present invention, the welding strength of the welding wire is tested after the ignition treatment, and adjustments are made according to the test results.

[0031] In the present invention, the method for testing the welding strength of the welding wire can use the conventional method disclosed in the prior art, such as: hanging a 500G weight on the welding wire, with the welding point located at 1 / 2 of the welding wire. If the weight can be lifted and raised and lowered at least three times without breaking the wire, it is considered qualified, otherwise it needs to be re-welded.

[0032] The present invention finds that if the weld is smooth without bulges or depressions, and the weld breaks when the weight is lifted, it is because the normalizing current is too small, resulting in loose welding, and the normalizing current needs to be adjusted. If the weld is bulging, blackening, and bending, it is because the top force of the welding current wire head is too large, and the welding current and the top force of the wire head need to be adjusted.

[0033] According to a wire welding method with a broken tungsten wire provided by the present invention, when testing the welding strength of the welding wire, if the welding point is smooth without bulges or depressions, the welding point is broken by lifting the weight, and the normalizing current is adjusted to 14-15 mA.

[0034] According to a wire welding method for a broken tungsten wire provided by the present invention, when testing the welding strength of the welding wire, if the welding point is bulging, blackening and bending, the welding current is adjusted to 22-26 mA; and the wire head top force is adjusted to 0.8-1.5 N.

[0035] During the specific implementation process, if the weld is bulging, blackening and bending, the welding current can be adjusted to 22 mA, 23 mA, 24 mA, 25 mA or 26 mA; the wire head top force can be adjusted to 0.8 N, 0.9 N, 1.0 N, 1.1 N, 1.2 N, 1.3 N, 1.4 N or 1.5 N, and any two of the above values ​​are range values ​​of endpoint values.

[0036] In a second aspect, the present invention provides a method for cutting crystalline silicon, comprising cutting crystalline silicon using a bonding wire obtained by the bonding wire method of breaking a tungsten wire.

[0037] According to a preferred embodiment of the present invention, welding wires with qualified welding strength are collected into a wire mesh, and welding point running begins after the wire collection is completed; the welding point running line speed is controlled to be 8-12 m / s.

[0038] In the present invention, when closing the welding point, the tungsten wire is manually pulled and placed in a small rotating wheel, and the guide wheel is slowly rotated. The rotation of the guide wheel forms a tension difference with the wire mesh, and the tungsten wire is slowly tightened until it is close to the guide wheel. After a complete wire mesh is formed, check whether there is any wire jump at the wire mesh collection position; if there is any, it needs to be handled in time.

[0039] In the present invention, the welding point running starts after the wire winding is finished, the kilometers required for the welding point to be run to the wire winding are calculated according to the wire break position, the wire running length is set, the wire running speed is manually adjusted to 8-12 meters / second, and the welding point running starts; the welding point running line speed can be 8 meters / second, 9 meters / second, 10 meters / second, 11 meters / second or 12 meters / second.

[0040] The line speed of conventional solder joints is usually 20 meters per second. The tungsten wire jitter at this line speed will cause the color difference lines to become wider. However, the present invention finds that by reducing the line speed to the above range during solder joints, the tungsten wire jitter caused by high-speed line running can be reduced, thereby reducing the width of the color difference lines.

[0041] According to a preferred implementation manner provided by the present invention, the re-machine process is modified, the table speed is first reduced to 75%~85% of the original speed, and then restored to the original table speed; the line speed is first reduced to 75%~85% of the original speed, and then restored to the original line speed.

[0042] According to a preferred embodiment provided by the present invention, the recovery process is modified, the table speed is first reduced to 75% of the original speed, then reduced to 85% of the original speed, and then restored to the original table speed; the line speed is first reduced to 75% of the original speed, then reduced to 85% of the original speed, and then restored to the original line speed.

[0043] According to a preferred embodiment provided by the present invention, the re-machine process adopts a small cycle cutting mode, which specifically includes the following steps: first supply 495 to 505 meters of wire and return 445 to 455 meters of wire; then supply 595 to 605 meters of wire and return 545 to 555 meters of wire.

[0044] According to a preferred embodiment provided by the present invention, the re-machine process adopts a small cycle cutting mode, which specifically includes the following steps: first supply 500 meters of wire and return 450 meters of wire; then supply 600 meters of wire and return 550 meters of wire.

[0045] The re-machine cutting modification process of the present invention adopts a small cycle cutting mode, which can reduce the color difference caused by cutting.

[0046] According to a preferred embodiment provided by the present invention, a method for cutting crystalline silicon using a bonding wire obtained by a bonding wire method of breaking a tungsten wire comprises the following steps: ① Push the wire bonding machine into the wire bonding position, turn on the power switch, and confirm the welding parameters.

[0047] ②Take the thread ends at both ends of the broken wire, cut them neatly and place them in the groove of the clamp block to clamp them, and click the ignition button to align the thread ends flatly front, back, left and right.

[0048] ③ Turn the clamping block screw to adjust the wire head force to make it slightly arched, and press the welding button to weld; control the welding current to 20~26 mA and the welding time to 10~15 seconds.

[0049] ④ After welding, cooling treatment is carried out and natural cooling is carried out in the air. The cooling time is 18~22 seconds.

[0050] ⑤ After cooling, normalizing treatment and ignition treatment are carried out in sequence, the normalizing treatment time is 300-350 milliseconds, the normalizing treatment current is 12-15 mA, the ignition treatment time is 2-5 seconds, and the ignition treatment current is 12-16 mA.

[0051] ⑥ Remove the tungsten wire to test the welding strength, hang a 500G weight on the tungsten wire, and the welding point is located at 1 / 2 of the tungsten wire. If it can lift the 500G weight and rise and fall three times without wire breakage, it is qualified. Otherwise, it needs to be re-welded.

[0052] ⑦ Close the welding point, manually pull the tungsten wire and place it in the small wheel, slowly rotate the guide wheel, and form a tension difference with the wire mesh through the rotation of the guide wheel. Slowly tighten the tungsten wire until it is close to the guide wheel. After forming a complete wire mesh, check whether there is any jumper at the wire mesh collection position.

[0053] ⑧ Start running the welding points after the wire is taken up. Calculate the number of kilometers required from the welding point to the wire taking up according to the wire break position, set the wire running length, adjust the manual wire running speed to 8~12 m / s, and start running the welding points.

[0054] ⑨ Modify the process and start the machine. Modify the original process at the wire break position. First reduce the table speed to 75%~85% of the original, and then restore the original table speed; first reduce the line speed to 75%~85% of the original, and then restore the original line speed. The recovery process adopts a small cycle cutting mode, first supply 495~505 meters of wire, return 445~455 meters; then supply 595~605 meters of wire, return 545~555 meters.

[0055] In a third aspect, the present invention provides an application of the wire bonding method for a broken tungsten wire or the method for cutting crystalline silicon to improve the color difference caused by the broken wire bonding.

[0056] In order to further illustrate the technical solution of the present invention, the present invention provides the following specific embodiments and comparative examples.

[0057] Unless otherwise specified, the various raw materials used in the examples and comparative examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0058] In the following embodiments, if in step ⑥, adjustments are made according to the surface conditions and test results of the previous weld, if the weld is smooth without bulges or depressions, the weld is broken by lifting the weight, and the normalizing current is increased within the range of 12 to 15 mA; if the weld is bulging, blackening, and bending, the welding current is reduced within the range of 22 to 26 mA, and the wire head top force is 0.8-1.5 N.

[0059] Example 1 This embodiment provides a method for cutting crystalline silicon using a bonding wire obtained by a bonding wire bonding method using a tungsten wire breakage method, comprising the following steps: ① Push the wire bonding machine into the wire bonding position, turn on the power switch, and confirm the welding parameters.

[0060] ②Take the thread ends at both ends of the broken wire, cut them neatly and place them in the groove of the clamp block to clamp them, and click the ignition button to align the thread ends flatly front, back, left and right.

[0061] ③ Turn the clamping block screw to adjust the wire head force to make it slightly arched, and press the welding button to weld; control the welding current to 22 mA and the welding time to 11 seconds.

[0062] ④ After welding, cooling treatment is carried out and natural cooling is carried out in the air. The cooling time is 8 seconds.

[0063] ⑤ After cooling, normalizing treatment and ignition treatment are carried out in sequence, the normalizing treatment time is 300 milliseconds, the normalizing treatment current is 13 mA; the ignition treatment time is 3 seconds, and the ignition treatment current is 14 mA.

[0064] ⑥ Remove the tungsten wire to test the welding strength, hang a 500g weight on the tungsten wire, and the welding point is located at 1 / 2 of the tungsten wire. If it can lift the 500G weight and rise and fall three times without broken wire, it is qualified. Otherwise, it needs to be re-welded.

[0065] ⑦ Close the welding point, manually pull the tungsten wire and place it in the small wheel, slowly rotate the guide wheel, and form a tension difference with the wire mesh through the rotation of the guide wheel. Slowly tighten the tungsten wire until it is close to the guide wheel. After forming a complete wire mesh, check whether there is any jumper at the wire mesh collection position.

[0066] ⑧ Start running the welding points after the wire is taken up. Calculate the number of kilometers required from the welding point to the wire taking up according to the wire break position, set the wire running length, adjust the manual wire running speed to 10 m / s, and start running the welding points.

[0067] ⑨ Modify the process and start the machine. Modify the original process at the wire break position. The table speed is reduced from 2.5 mm / min to 75% of the original table speed to 1.8 mm / min, and then to 85% of the original table speed to 2 mm / min, and then restored to the original table speed to 2.5 mm / min; the line speed is reduced from 38 m / s to 75% of the original line speed to 28 m / s, and then to 85% of the original line speed to 32 m / s based on the original process. Use small cycle cutting to transition the supply line to 500m and the return line to 450m; the supply line is 600m and the return line is 550m.

[0068] Example 2 This embodiment provides a method for cutting crystalline silicon using a welding wire obtained by a welding wire bonding method using broken tungsten wires, and the only difference between this method and Embodiment 1 is that in step ⑨, the table speed and line speed are changed as follows: the first step is changed to 80% of the table speed of the original process; the second step is changed to 90% of the table speed of the original process; the third step restores the original table speed, and the line speed is set at 80% of the original line speed.

[0069] Example 3 This embodiment provides a method for cutting crystalline silicon using a bonding wire obtained by a bonding wire breaking method using a tungsten wire, which differs from Embodiment 1 only in that step ⑤ is not included.

[0070] Example 4 This embodiment provides a method for cutting crystalline silicon using a welding wire obtained by a welding method of breaking a tungsten wire. The difference between this method and Embodiment 1 is that in step ③, the welding current is controlled to be 25 mA and the welding time is 11 seconds.

[0071] Comparative Example 1 This comparative example provides a method for cutting crystalline silicon using a welding wire obtained by a welding method of breaking a tungsten wire, which differs from Example 1 only in that in step ③, the welding current is controlled to be 28 mA and the welding time is 8 seconds.

[0072] Test example The present invention verifies the cutting method of the above embodiment and comparative example, and the results are shown in Table 1: Test method: Use Autevi AM018TC high-speed silicon wafer sorter for detection. The detection module consists of two sets of customized combined light sources, and a special diffuse reflection light path design to effectively present oil stains, water marks, fingerprints, scratches and other defective types on the silicon wafer surface. High-quality acquisition is achieved through two sets of 8K high-definition high-sensitivity line scan cameras and matching lenses. The defect position and defect attributes (area, size, etc.) are comprehensively located through image contrast and its geometric characteristics and distribution characteristics of defects, and the grade judgment is made. The width of the silicon wafer sorting color difference line is ≤2mm, and the color difference position area cannot be obviously bright.

[0073] Table 1

[0074] The crystalline silicon obtained by the cutting method provided in Example 1 is shown in FIG. Figure 1 The crystalline silicon obtained by the cutting method provided in Comparative Example 1 is shown in FIG. Figure 2 .

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wire bonding method for breaking a tungsten wire, characterized in that: include: When welding the weld point, control the welding current to 22~26 mA and the welding time to 10~15 seconds.

2. The wire bonding method for breaking a tungsten wire according to claim 1, characterized in that: After welding, cooling treatment, normalizing treatment and ignition treatment are carried out in sequence; The normalizing treatment time is 300-350 milliseconds, and the normalizing treatment current is 12-15 mA; and / or, the ignition treatment time is 2-5 seconds, and the ignition treatment current is 12-16 mA.

3. The wire bonding method for breaking a tungsten wire according to claim 2, characterized in that: The welding strength of the welding wire is tested after the ignition treatment, and adjustments are made according to the test results.

4. The wire bonding method for breaking a tungsten wire according to claim 3, characterized in that: When testing the welding strength of the welding wire, if the welding point is smooth without bulges or depressions, and the welding point breaks when the weight is lifted, adjust the normalizing current to 14~15 mA.

5. The wire bonding method for breaking a tungsten wire according to claim 3, characterized in that: When testing the welding strength of the welding wire, if the welding point is bulging, blackening and bending, adjust the welding current to 22~24 mA; adjust the wire head force to 0.8~1.5 N.

6. A method for cutting crystalline silicon, characterized in that: The method comprises cutting crystalline silicon with a bonding wire obtained by the bonding wire method for breaking a tungsten wire according to any one of claims 1 to 5.

7. The method for cutting crystalline silicon according to claim 6, characterized in that: include: The welding wires with qualified welding strength are gathered into the wire net, and the welding points are started after the wire gathering is completed; the welding point line speed is controlled to be 8~12 m / s.

8. The method for cutting crystalline silicon according to claim 6 or 7, characterized in that: Modify the recovery process: first reduce the table speed to 75%~85% of the original speed, and then restore the original table speed; first reduce the line speed to 75%~85% of the original speed, and then restore the original line speed.

9. The method for cutting crystalline silicon according to claim 8, characterized in that: The re-machine process adopts a small cycle cutting mode, which specifically includes the following steps: first supply 495~505 meters of wire and return 445~455 meters of wire; then supply 595~605 meters of wire and return 545~555 meters of wire.

10. Use of the wire bonding method for broken tungsten wires as claimed in any one of claims 1 to 5 or the method for cutting crystalline silicon as claimed in any one of claims 6 to 9 in improving the color difference caused by broken wire bonding.

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