Material lifting method of silicon wafer and silicon wafer

Abstract

The embodiment of the invention provides a silicon wafer lifting method and a silicon wafer, and the method comprises the steps: completely cutting a crystal bar into silicon wafers through a cutting line, and controlling the silicon wafers to move upwards; and in the process of controlling the silicon wafer to move upwards, controlling the cutting line to alternately and circularly move in the positive and negative directions. According to the silicon wafer lifting method provided by the embodiment of the invention, the contact area of the silicon wafer clamping the cutting line is smaller by utilizing the characteristic that the wire bow of the forward and reverse routing is smaller than that of the one-way routing, so that the probability that the cutting line forms scratches on the surface of the silicon wafer in the lifting process can be reduced, the condition of wafer falling during lifting can be reduced, and the lifting efficiency of the silicon wafer is improved. The method has the advantages of fast speed increase, high surface quality of the prepared silicon wafer and small secondary damage.

Description

Technical Field

[0001] The present application relates to the technical field of crystalline silicon solar cell manufacturing, and particularly to a method for lifting silicon wafers and silicon wafers. Background Art

[0002] With the development of the photovoltaic industry, silicon wafers have become thinner and thinner, making it increasingly difficult to lift them.

[0003] In the prior art, the method for lifting silicon wafers is that the feeding table moves upward at a certain speed, and at the same time, the steel wire moves uniformly in one direction at another speed. The two components move in cooperation to lift the cut silicon wafers out of the wire mesh, realizing the lifting after the silicon wafers are cut.

[0004] However, the above-mentioned lifting method is likely to cause wafer dropping during lifting and scratches on the surface of the silicon wafers, thereby reducing the surface quality of the silicon wafers. Summary of the Invention

[0005] The technical problem to be solved by the present application is to provide a method for lifting silicon wafers to solve the problems that the existing method for lifting silicon wafers is likely to cause wafer dropping during lifting and scratches on the surface of the silicon wafers.

[0006] To solve the above problems, the present application is implemented by the following technical solutions:

[0007] The present application provides a method for lifting silicon wafers, which includes:

[0008] After cutting a crystal bar completely into silicon wafers with a cutting wire, controlling the silicon wafers to move upward;

[0009] During the process of controlling the silicon wafers to move upward, controlling the cutting wire to move in an alternating cycle in the forward and reverse directions.

[0010] Further, in the method for lifting silicon wafers, controlling the cutting wire to move in the forward and reverse directions alternately includes:

[0011] During the commutation stage, controlling the cutting wire to switch the movement direction within 0 - 0.5 s and accelerate to 0.01 - 1 m / s within 4 - 7 s;

[0012] During the non - commutation stage, controlling the cutting wire to move at a constant speed of 0.01 - 1 m / s.

[0013] Further, in the method for lifting silicon wafers, in each forward - and - reverse - direction alternating cycle, the distance that the cutting wire moves in the forward direction is equal to the distance that it moves in the reverse direction.

[0014] Further, in the method for lifting silicon wafers, in each forward - and - reverse - direction alternating cycle, the distance that the cutting wire moves in a single direction is 0.05 - 30 m.

[0015] Further, in the method for lifting the silicon wafer, controlling the upward movement of the silicon wafer includes:

[0016] Determining a feed rate according to the lifting height of the silicon wafer; wherein, the feed rates corresponding to different lifting heights are at least partially different;

[0017] Controlling the silicon wafer to move upward at the feed rate.

[0018] Further, in the method for lifting the silicon wafer, before determining the feed rate according to the lifting height of the silicon wafer, the method further includes:

[0019] Determining the corresponding relationship between the lifting height of the silicon wafer and the feed rate; wherein, in the corresponding relationship, the feed rates corresponding to different lifting heights are at least partially different, so that when the silicon wafer is controlled to move upward at the feed rate determined according to the corresponding relationship, the scratches formed by the cutting wire on the silicon wafer tend to be uniform;

[0020] Determining the feed rate according to the lifting height of the silicon wafer includes:

[0021] Determining the feed rate according to the lifting height and the corresponding relationship.

[0022] Further, in the method for lifting the silicon wafer, the lifting process of the silicon wafer sequentially includes a starting section, an intermediate section, and an ending section;

[0023] Determining the feed rate according to the lifting height of the silicon wafer includes:

[0024] Controlling the first feed rate of the silicon wafer to be less than the second feed rate, where the first feed rate is the upward movement speed of the silicon wafer in the starting section, and the second feed rate is the upward movement speed of the silicon wafer in the intermediate section;

[0025] Controlling the third feed rate of the silicon wafer to be greater than or equal to the second feed rate, where the third feed rate is the upward movement speed of the silicon wafer in the ending section.

[0026] Further, in the method for lifting the silicon wafer, the first feed rate is 20 - 40 mm / min, the second feed rate is 40 - 80 mm / min, and the third feed rate is 80 - 600 mm / min.

[0027] Further, the method for lifting the silicon wafer further includes:

[0028] During the process of controlling the cutting wire to move in an alternating cycle in the forward and reverse directions, spraying a cutting fluid onto the contact area between the silicon wafer and the cutting wire.

[0029] The present application also provides a silicon wafer, which is processed by the above-mentioned lifting method.

[0030] Compared with the prior art, the embodiments of the present application include the following advantages:

[0031] In the embodiments of the present application, for the method of lifting a silicon wafer, after a single crystal bar is completely cut into silicon wafers by a cutting wire, the silicon wafer is controlled to move upward, and during the process of controlling the upward movement of the silicon wafer, the cutting wire is controlled to move in an alternating cycle in the forward and reverse directions; wherein, by using the characteristic that the wire bow with forward and reverse wire walking is smaller than the wire bow with single-direction wire walking, the contact area between the silicon wafer and the cutting wire is smaller, which can not only reduce the probability of the cutting wire forming scratches on the surface of the silicon wafer during the lifting process, but also reduce the situation of wafer dropping during lifting, and has the advantages of fast speed increase, high surface quality of the obtained silicon wafer, and small secondary damage.

[0032] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic structural diagram of the silicon wafer lifting process in the prior art;

[0034] Figure 2 is a flow chart of the method for lifting a silicon wafer provided in Embodiment 1 of the present application;

[0035] Figure 3 is a schematic structural diagram of the silicon wafer lifting process in the embodiments of the present application;

[0036] Figure 4 is a flow chart of the method for lifting a silicon wafer provided in Embodiment 2 of the present application;

[0037] Figure 5 is a flow chart of the method for lifting a silicon wafer provided in Embodiment 3 of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] The applicant of the present application found that in the existing silicon wafer production technology, such as Figure 1As shown, after the silicon wafer 20 is completely cut, it moves upward at a certain speed through the feeding table. At the same time, the cutting wire 10 travels in one direction at a certain speed. The combination of the two lifts the cut silicon wafer from the wire mesh until the lower surface of the silicon wafer separates from the wire mesh. During the above-mentioned material lifting process, because the wire mesh carries cutting fluid, under the tension of the cutting fluid, a large adsorption force is generated between the wire mesh and the silicon wafer, causing the steel wire to be adsorbed on the surface of the silicon wafer. Therefore, when the silicon wafer is lifted, the steel wire will be forced to stretch to form a reverse wire arch, increasing the contact area between the steel wire and the silicon wafer, and increasing the probability of the silicon wafer separating from the resin plate or the sticking glue during material lifting, resulting in material dropping; at the same time, the large contact area is likely to cause scratches on the surface of the silicon wafer, reducing the surface quality of the silicon wafer; in addition, the increase in the reverse wire arch causes the steel wire to contact the lower edge of the mortar pipe after being lifted, easily causing multiple breaks in the steel wire in the wire mesh, and then resulting in a large number of scratches on the silicon wafer, having a significant impact on the yield.

[0040] To solve the above problems, an embodiment of the present application provides a method for lifting a silicon wafer, aiming to reduce scratches on the surface of the silicon wafer caused by the cutting wire during the material lifting process and improve the quality of the silicon wafer.

[0041] Embodiment 1

[0042] Please refer to Figure 2 , Figure 2 which shows a step flow chart of a method for lifting a silicon wafer in Embodiment 1 of the present application. This method is applied to the material lifting process of the silicon wafer, and this method may include Step 101 to Step 102.

[0043] The method for lifting a silicon wafer provided by the embodiment of the present application, as Figure 3 shown, is used to separate the silicon wafer 20 from the cutting wire 10 after the cutting wire 10 cuts the ingot into the silicon wafer 20. Among them, before cutting, the ingot is bonded to the feeding table (not shown) through a resin plate and a sticking glue, and the feeding table is controlled to move up and down through an external controller, which can drive the ingot and the silicon wafer to move up and down. Among them, the cutting wire winds from one main roller 30 to another main roller 30, and the rotation of the main roller 30 can drive the movement of the cutting wire 10 to realize the cutting of the silicon rod. The above-mentioned cutting wire 10 may specifically be a diamond wire.

[0044] Step 101: After cutting the ingot completely into a silicon wafer with a cutting wire, control the silicon wafer to move upward.

[0045] In step 101, the crystal rod to be cut is first bonded to the feed table by a resin plate or a rod bonding glue, and then the feed table is controlled to move downward and the cutting line is controlled to continue to move through an external controller, so that the silicon rod can be cut until the cutting line cuts to the resin plate and the silicon rod is completely cut through into silicon wafers; because the silicon wafer is still bonded to the feed table after the silicon rod is cut into silicon wafers, the silicon wafer can be driven to move up by controlling the feed table to move up, so that the cutting line re-enters between adjacent silicon wafers from the resin plate until the lower surface of the silicon wafer is separated from the cutting line network.

[0046] Step 102: In the process of controlling the upward movement of the silicon wafer, the cutting line is controlled to move in a positive and negative direction alternately.

[0047] In step 102, while controlling the upward movement of the silicon wafer, at the same time, Figure 2 As shown, the main rollers 30 on the left and right sides are controlled to act as active rollers in turn, so as to control the cutting line 10 to move in alternating cycles in forward and reverse directions.

[0048] Among them, because the unidirectional routing is continuously pulled in one direction, the deformation formed is large, and the reverse line bow is large; while in the forward and reverse routing, the deformation formed by the cutting line during the silicon wafer lifting process is decomposed in both directions, resulting in a smaller reverse line bow, making the contact area between the silicon wafer and the cutting line 10 smaller, which can not only reduce the scratches on the silicon wafer surface caused by the cutting line during the lifting process, but also reduce the situation of wafer falling during lifting, and has the advantages of fast speed increase, high surface quality of the silicon wafer and little secondary damage.

[0049] Optionally, in one implementation, controlling the silicon wafer to move upward includes steps 111 to 112:

[0050] Step 111, determining a feeding speed according to a lifting height of the silicon wafer; wherein the feeding speeds corresponding to different lifting heights are at least partially different;

[0051] Step 112: Control the silicon wafer to move upward according to the feeding speed.

[0052] In this embodiment, based on the fact that the friction force generated by the cutting line on the silicon wafer during the lifting process is affected by the contact area between the cutting line and the silicon wafer, and the contact area between the cutting line and the silicon wafer is affected by the lifting height, according to the fact that the lifting height affects the contact area between the cutting line and the silicon wafer, the feed speed of the silicon wafer is dynamically adjusted according to the lifting height, so that the probability of scratches on the silicon wafer caused by the cutting line at different lifting heights tends to be consistent, thereby reducing the scratches formed on the silicon wafer by the cutting line, and at the same time can speed up the lifting speed and improve production efficiency.

[0053] Optionally, in a specific embodiment, the above-mentioned silicon wafer extraction process includes a starting section, a middle section and an ending section in sequence;

[0054] Step 111 specifically includes the following:

[0055] Control the first feeding speed of the silicon wafer to be less than the second feeding speed, where the first feeding speed is the upward movement speed of the silicon wafer in the starting section, and the second feeding speed is the upward movement speed of the silicon wafer in the middle section;

[0056] Control the third feeding speed of the silicon wafer to be greater than or equal to the second feeding speed, where the third feeding speed is the upward movement speed of the silicon wafer in the ending section.

[0057] In this specific embodiment, the starting section is the stage when the cutting line enters the silicon wafer from the resin plate bonding the silicon wafer until it completely enters the silicon wafer. The middle section is the stage when the cutting line is completely inside the silicon wafer. The ending section is the stage when the cutting line starts to leave the silicon wafer until it completely leaves the silicon wafer. Taking a silicon wafer with a size of 182*182 mm as an example, the stage where the height difference between the main roller and the bottom of the silicon wafer is between 194 and 150 mm is the above-mentioned starting section, the stage where the height difference between the main roller and the bottom of the silicon wafer is between 150 and -5 mm is the above-mentioned middle section, and the stage where the height difference between the main roller and the bottom of the silicon wafer is between -5 and -20 mm is the above-mentioned ending section.

[0058] In this specific embodiment, the feeding speed is slower when the resin plate enters the silicon wafer, which can protect the edge surface of the silicon wafer. And in the ending section, since the contact area between the cutting line and the silicon wafer becomes smaller, controlling the feeding speed to be faster at this time can not only reduce scratches, but also save the overall feeding time and improve the feeding efficiency.

[0059] Optionally, in a specific embodiment, the above-mentioned first feeding speed can be 20 - 40 mm / min, the above-mentioned second feeding speed can be 40 - 80 mm / min, and the above-mentioned third feeding speed can be 80 - 600 mm / min.

[0060] Exemplarily, the above-mentioned first feeding speed can be one of 20 mm / min, 25 mm / min, 30 mm / min, 35 mm / min, 40 mm / min or the range value of any two of them. The above-mentioned second feeding speed can be one of 40 mm / min, 45 mm / min, 50 mm / min, 55 mm / min, 60 mm / min, 70 mm / min, 80 mm / min or the range value of any two of them. The above-mentioned third feeding speed can be one of 80 mm / min, 100 mm / min, 150 mm / min, 200 mm / min, 250 mm / min, 300 mm / min, 350 mm / min, 400 mm / min, 450 mm / min, 500 mm / min, 550 mm / min, 600 mm / min or the range value of any two of them.

[0061] Optionally, the method for lifting a silicon wafer provided by the embodiments of the present application further includes:

[0062] During the process of controlling the reciprocating cyclic movement of the cutting wire in the forward and reverse directions, spray cutting fluid onto the contact area between the silicon wafer and the cutting wire.

[0063] Wherein, when lifting the material, spray cutting fluid onto the contact areas between both sides of the silicon wafer and the cutting wire, so that during the forward and reverse running processes of the cutting wire, the cutting fluid is brought between adjacent silicon wafers through the cutting wire, thereby using the cutting fluid to play a lubricating role and further reducing the friction between the cutting wire and the silicon wafer.

[0064] Optionally, in one embodiment, the flow rate of the above-mentioned cutting fluid can be set to 100 - 300 kg / min, for example, it can be one of 100 kg / min, 150 kg / min, 300 kg / min, 250 kg / min, 3000 kg / min or the range value of any two of them; in some embodiments, the flow rate of the above-mentioned cutting fluid is set to 200 - 250 kg / min.

[0065] Optionally, in one embodiment, the slurry temperature of the above-mentioned cutting fluid is set to 15 - 25 °C, which can better exert the functions of the dispersant and lubricant in the cutting fluid and improve the lubrication effect; for example, the slurry temperature of the cutting fluid can be set to one of 15 °C, 16 °C, 17 °C, 18 °C, 19 °C, 20 °C, 21 °C, 22 °C, 23 °C, 24 °C, 25 °C or the range value of any two of them; in some embodiments, the slurry temperature of the above-mentioned cutting fluid is set to 18 - 20 °C.

[0066] In the embodiments of the present application, during the process of lifting a silicon wafer, controlling the reciprocating cyclic movement of the cutting wire in the forward and reverse directions can effectively alleviate the problems that the existing method for lifting a silicon wafer is prone to causing wafer dropping during lifting and scratches on the surface of the silicon wafer.

[0067] The present application also provides a silicon wafer, which is processed by the above-mentioned method for lifting a material.

[0068] Wherein, because during the process of lifting and preparing the above-mentioned silicon wafer, the method of reciprocating cyclic movement of the cutting wire in the forward and reverse directions is adopted, the reverse wire bow formed by the cutting wire can be reduced, so that the contact area between the silicon wafer and the cutting wire is smaller, and the scratches on the surface of the silicon wafer caused by the cutting wire during the lifting process can be significantly reduced. The obtained silicon wafer has high surface quality and small secondary damage.

[0069] Embodiment 2

[0070] Refer to Figure 4 , Figure 4The flowchart of the steps of a method for lifting a silicon wafer in the second embodiment of the present application is shown. This method is applied to the process of lifting a silicon wafer, and the method may include steps 201 to 204:

[0071] Step 201, determine the corresponding relationship between the lifting height and the feeding speed of the silicon wafer; wherein, in the corresponding relationship, the feeding speeds corresponding to different lifting heights are at least partially different, so that when the feeding speed determined according to the corresponding relationship is used to control the upward movement of the silicon wafer, the scratches formed by the cutting wire on the silicon wafer tend to be uniform.

[0072] In this step, starting from the fact that the probability of the cutting wire forming scratches on the silicon wafer during the lifting process is affected by the contact area size, and the contact area between the cutting wire and the silicon wafer changes with different lifting heights, the lifting speed that changes continuously with the lifting height of the silicon wafer and controls the scratches formed by the cutting wire on the silicon wafer to be uniform during the lifting process is pre-calculated, that is, the above corresponding relationship is determined.

[0073] Step 202, determine the feeding speed according to the lifting height and the corresponding relationship.

[0074] In this step, the above corresponding relationship stipulates the feeding speeds of the silicon wafer corresponding to different lifting heights. And when the upward movement of the silicon wafer is controlled at the feeding speed determined according to the corresponding relationship during the lifting process, the size of the reverse wire bow formed by the cutting wire tends to be uniform. Therefore, when the upward movement of the silicon wafer is controlled at the above feeding speed, the scratches between the cutting wire and the silicon wafer tend to be uniform and the scratch difference is small, so that the silicon wafer is not easily dropped and the quality of the silicon wafer is higher.

[0075] Step 203, control the silicon wafer to move upward at the feeding speed.

[0076] This step can specifically refer to the above step 112 and will not be elaborated here.

[0077] Step 204, during the process of controlling the silicon wafer to move upward, control the cutting wire to move in an alternating cycle in the forward and reverse directions.

[0078] This step can specifically refer to the above step 102 and will not be elaborated here.

[0079] Optionally, in an implementation manner, in the above step 204, controlling the cutting wire to move in the forward and reverse directions alternately includes steps 2041 to 2042:

[0080] Step 2041, in the commutation stage, control the cutting wire to switch the movement direction within 0 to 0.5 s and accelerate to 0.01 to 1 m / s within 4 to 7 s;

[0081] In step 2041, the commutation stage refers to the process of changing the driving roller shaft so that the cutting wire switches from forward movement to reverse movement, or from reverse movement to forward movement; in the commutation stage, within a short time of 0 to 0.5 s, the cutting wire is controlled to stop moving in the original movement direction, and the movement in the direction opposite to the original movement direction is started, and it is accelerated to 0.01 to 1 m / s within 4 to 7 s, which can effectively reduce the reverse wire bow and avoid increasing the burden on the motor driving the roller to rotate.

[0082] Step 2042: In the non-commutation stage, control the cutting wire to move at a constant speed of 0.01 to 1 m / s.

[0083] In this step 2042, in the non-commutation stage, controlling the cutting wire to move at a constant speed of 0.01 to 1 m / s can better match the rising rate of the silicon wafer and avoid forming horizontal or vertical scratches.

[0084] Optionally, in a specific embodiment, in each forward and reverse direction alternating cycle, the distance of the cutting wire moving in the forward direction is equal to the distance of the cutting wire moving in the reverse direction, which can more evenly offset the scratches on the silicon wafer caused by the forward and reverse movements, and further improve the quality of the silicon wafer.

[0085] Optionally, in a specific embodiment, in each forward and reverse direction alternating cycle, the distance of the cutting wire moving in a single direction is 0.05 to 30 m, which can not only reduce the reverse wire bow of the cutting wire, but also fully utilize the forward and reverse movement of the cutting wire to bring the cutting wire into the silicon wafer, effectively reducing the contact area between the cutting wire and the silicon wafer, thereby reducing the scratches on the surface of the silicon wafer.

[0086] Optionally, in some embodiments, in each forward and reverse direction alternating cycle, the distance of the cutting wire moving in a single direction can be one of 0.05 m, 0.1 m, 0.2 m, 0.4 m, 0.6 m, 0.8 m, 1 m, 1.2 m, 1.5 m, 1.8 m, 2 m, 2.2 m, 2.5 m, 2.8 m, 3 m, 5 m, 8 m, 10 m, 15 m, 20 m, 25 m, 30 m or the range value of any two of them.

[0087] In the embodiments of the present application, by controlling the running distance, running speed and acceleration / deceleration time of the cutting wire in the forward and reverse directions, controlling the commutation frequency of the cutting wire, and matching the feeding table speed under different lifting heights, the wire bow formed by the cutting wire being clamped by the silicon wafer can be made smaller, the contact area between the silicon wafer and the cutting wire is smaller, which has a positive effect on the scratches on the surface of the silicon wafer.

[0088] Embodiment III

[0089] Refer to Figure 5 , Figure 5The flowchart of steps of a method for lifting a silicon wafer in the third embodiment of the present application is shown. This method is applied to the process of lifting a silicon wafer. The above-mentioned process of lifting the silicon wafer sequentially includes a starting section, an intermediate section, and an ending section;

[0090] This method may include steps 301 to 304:

[0091] Step 301: Determine the feeding speed according to the lifting height of the silicon wafer. Among them, when the lifting height is in the starting section of the lifting process, the feeding speed is 20 - 40 mm / min; when the lifting height is in the intermediate section of the lifting process, the feeding speed is 40 - 80 mm / min; when the lifting height is in the ending section of the lifting process, the feeding speed is 80 - 600 mm / min.

[0092] For this step, reference may specifically be made to the above-mentioned step 111, and details will not be elaborated here.

[0093] Step 302: Control the silicon wafer to move upward at the feeding speed.

[0094] For this step, reference may specifically be made to the above-mentioned step 112, and details will not be elaborated here.

[0095] Step 303: During the process of controlling the silicon wafer to move upward, control the cutting wire to move in an alternating cycle in the forward and reverse directions. Among them, during the commutation stage, control the cutting wire to switch the movement direction within 0 - 0.5 s and accelerate to 0.01 - 1 m / s within 4 - 7 s; during the non - commutation stage, control the cutting wire to move at a uniform speed of 0.01 - 1 m / s, and in each forward and reverse alternating cycle, the movement distance in a single direction is 0.05 - 30 m.

[0096] For this step, reference may specifically be made to the above-mentioned step 204, and details will not be elaborated here.

[0097] In the embodiment of the present application, by controlling the running distance, running speed, and acceleration and deceleration time of the cutting wire in the forward and reverse directions, and matching the feeding table speed at different lifting heights, the wire bow formed by the cutting wire being clamped by the silicon wafer can be made smaller, the contact area between the silicon wafer and the cutting wire can be made smaller, and the probability of forming scratches on the silicon wafer surface can be significantly reduced.

[0098] To make the invention purpose, technical solution, and beneficial effects of the present invention clearer, the present invention will be further described below in conjunction with embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0099] Embodiment 1

[0100] After the M10 silicon wafer is completely cut, the silicon wafer is raised and the steel wire used as the cutting wire is controlled to perform alternating forward and reverse circular motions according to the parameters shown in Table 1, based on the lifting height of the silicon wafer. Cutting fluid is sprayed on both sides of the silicon wafer, and the cut silicon wafer is lifted from the wire mesh until the lower surface of the silicon wafer is separated from the wire mesh to obtain the silicon wafer.

[0101] Table 1

[0102]

[0103] Example 2

[0104] After the M10 silicon wafer is completely cut, the silicon wafer is raised and the steel wire used as the cutting wire is controlled to perform alternating forward and reverse circular motions according to the parameters shown in Table 2, based on the lifting height of the silicon wafer. Cutting fluid is sprayed on both sides of the silicon wafer, and the cut silicon wafer is lifted from the wire mesh until the lower surface of the silicon wafer is separated from the wire mesh to obtain the silicon wafer.

[0105] Table 2

[0106]

[0107] Example 3

[0108] After the M10 silicon wafer is completely cut, the silicon wafer is raised and the steel wire used as the cutting wire is controlled to perform alternating forward and reverse circular motions according to the parameters shown in Table 3, and cutting liquid is sprayed on both sides of the silicon wafer. The cut silicon wafer is lifted from the wire mesh until the lower surface of the silicon wafer is separated from the wire mesh to obtain the silicon wafer.

[0109] Table 3

[0110]

[0111] Example 4

[0112] After the M10 silicon wafer is completely cut, the silicon wafer is raised and the steel wire used as the cutting wire is controlled to perform alternating forward and reverse circular motions according to the parameters shown in Table 4, based on the lifting height of the silicon wafer, and the cutting liquid is sprayed on both sides of the silicon wafer. The cut silicon wafer is lifted from the wire mesh until the lower surface of the silicon wafer is separated from the wire mesh to obtain the silicon wafer.

[0113] Table 4

[0114]

[0115] Comparative Example 1

[0116] After the M10 silicon wafer is completely cut, the silicon wafer is raised and the steel wire used as the cutting wire is controlled to move unidirectionally according to the parameters shown in Table 5, and cutting liquid is sprayed on both sides of the silicon wafer. The cut silicon wafer is lifted from the wire mesh until the lower surface of the silicon wafer is separated from the wire mesh to obtain the silicon wafer.

[0117] Table 5

[0118]

[0119] The silicon wafers prepared in Examples 1 to 4 and Comparative Example 1 were respectively subjected to surface scratch tests, and the results are shown in Table 6.

[0120] Table 6

[0121] Group Scratch Example 1 0.83％ Example 2 1.9％ Example 3 0.49％ Example 4 0.62％ Comparative Example 1 3.1％

[0122] Experiments show that compared with the conventional process of controlling the unidirectional movement of the cutting line, in the embodiment of the present application, during the process of controlling the upward movement of the silicon wafer, the cutting line is controlled to move in an alternating cycle in the forward and reverse directions. The surface scratches of the obtained silicon wafers are significantly less than those of the silicon wafers obtained by the conventional process, indicating that the method provided in the embodiment of the present application can effectively reduce the scratches formed on the silicon wafer surface during the material lifting process, and the quality of the silicon wafer is significantly improved.

[0123] In summary, in this embodiment, the provided method for lifting a silicon wafer, after cutting a crystal bar completely into silicon wafers with a cutting line, controls the upward movement of the silicon wafer, and during the process of controlling the upward movement of the silicon wafer, controls the cutting line to move in an alternating cycle in the forward and reverse directions; wherein, the characteristic that the wire bow of the forward and reverse direction wire walking is smaller than that of the unidirectional wire walking makes the contact area between the silicon wafer and the cutting line smaller, which can not only reduce the probability of the cutting line forming scratches on the silicon wafer surface during the material lifting process, but also reduce the situation of material dropping during material lifting, and has the advantages of fast speed, high surface quality of the obtained silicon wafers, and small secondary damage.

[0124] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the claims are intended to be construed to include the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present application.

[0125] The above provides a detailed introduction to the method and silicon wafer for lifting a silicon wafer provided by the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for lifting a silicon wafer, characterized in that, Including: After cutting a single crystal rod completely into wafers with a cutting wire, controlling the upward movement of the wafers; During the process of controlling the upward movement of the wafers, controlling the cutting wire to move in an alternating cycle in the forward and reverse directions.

2. The lifting method according to claim 1, characterized in that, Controlling the cutting wire to move in the forward and reverse directions alternately includes: In the commutation stage, controlling the cutting wire to switch the movement direction within 0 to 0.5 s and accelerate to 0.01 to 1 m / s within 4 to 7 s; In the non-commutation stage, controlling the cutting wire to move at a constant speed of 0.01 to 1 m / s.

3. The lifting method according to claim 1, characterized in that, In each forward and reverse direction alternating cycle, the distance that the cutting wire moves in the forward direction is equal to the distance that it moves in the reverse direction.

4. The lifting method according to claim 3, characterized in that, In each forward and reverse direction alternating cycle, the distance that the cutting wire moves in a single direction is 0.05 to 30 m.

5. The lifting method according to claim 1, characterized in that, Controlling the upward movement of the wafers includes: Determining a feeding speed according to the lifting height of the wafers; wherein, the feeding speeds corresponding to different lifting heights are at least partially different; Controlling the upward movement of the wafers at the feeding speed.

6. The lifting method according to claim 5, characterized in that, Before determining the feeding speed according to the lifting height of the wafers, the method further includes: Determining the corresponding relationship between the lifting height of the wafers and the feeding speed; wherein, in the corresponding relationship, the feeding speeds corresponding to different lifting heights are at least partially different, so that when the wafers are controlled to move upward at the feeding speed determined according to the corresponding relationship, the scratches formed by the cutting wire on the wafers tend to be uniform; Determining the feeding speed according to the lifting height of the wafers includes: Determining the feeding speed according to the lifting height and the corresponding relationship.

7. The lifting method according to claim 5, characterized in that, The process of lifting the wafers sequentially includes a starting section, an intermediate section, and an ending section; Determining the feeding speed according to the lifting height of the wafers includes: Controlling the first feeding speed of the wafers to be less than the second feeding speed, where the first feeding speed is the upward movement speed of the wafers in the starting section, and the second feeding speed is the upward movement speed of the wafers in the intermediate section; Controlling the third feeding speed of the wafers to be greater than or equal to the second feeding speed, where the third feeding speed is the upward movement speed of the wafers in the ending section.

8. The lifting method according to claim 7, characterized in that, The first feeding speed is 20 to 40 mm / min, the second feeding speed is 40 to 80 mm / min, and the third feeding speed is 80 to 600 mm / min.

9. The lifting method according to claim 1, characterized in that, The method further includes: During the process of controlling the cutting wire to move in an alternating cycle in the forward and reverse directions, spraying a cutting fluid onto the contact area between the wafers and the cutting wire.

10. A silicon wafer, characterized in that, Processed by the wafer lifting method according to any one of claims 1 to 9.

Images