A processing method of a roller assembly and a crystal bar cutting device

Abstract

The application discloses a processing method of a roller assembly and a crystal bar cutting device. The roller assembly comprises an outgoing roller and an incoming roller. The processing method of the roller assembly comprises the following steps: providing two cylindrical roller bodies for preparing the outgoing roller and the incoming roller respectively; forming winding grooves on the side surfaces of the roller bodies to form the outgoing roller and the incoming roller; and the winding groove depth of the outgoing roller is less than that of the incoming roller corresponding to the same cutting line. When the winding grooves are formed, the winding groove depth of the outgoing roller corresponding to the same cutting line is less than that of the incoming roller, so that the cutting depths of the incoming end cutting line and the outgoing end cutting line to the crystal bar are the same, and the difference in the warping of the wafer caused by the different cutting depths of the incoming end cutting line and the outgoing end cutting line can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor material processing, and more particularly, to a processing method of a roller assembly and a crystal bar cutting device. BACKGROUND

[0002] Each groove on a general roller has the same morphology, angle, depth and pitch to ensure that the cut silicon carbide wafer has the same thickness and warping. But in the actual multi-wire cutting process, for example, in the cutting process with free abrasive: the steel wire participates in the cutting, and its surface will be gradually scraped and ground by diamond particles, and the diameter of the steel wire will become thinner, and the cutting depth of the steel wire at the wire entry and exit ends is not consistent. During the cutting process, the cutting speed continuously changes, and in fact, at the same cutting depth, the cutting speed (feed speed) at the wire entry and exit ends is different, which causes the difference in wafer warping at the wire entry and exit ends. SUMMARY

[0003] Therefore, the present application provides a processing method of a roller assembly and a crystal bar cutting device, and the scheme is as follows: a processing method of a roller assembly, the roller assembly comprising a wire exit roller and a wire entry roller, the processing method comprising:

[0004] providing two cylindrical roller bodies for preparing the wire exit roller and the wire entry roller, respectively;

[0005] forming wire grooves on the side surface of the roller body to form the wire exit roller and the wire entry roller;

[0006] wherein, for the same cutting wire, the wire groove depth of the wire exit roller is less than the wire groove depth of the wire entry roller.

[0007] Preferably, in the above processing method, for the same cutting wire, the relationship between the wire groove depth of the wire exit roller and the wire groove depth of the wire entry roller satisfies:

[0008] d1=d2-A*N;

[0009] wherein, d1 is the wire groove depth of the wire exit roller, d2 is the wire groove depth of the wire entry roller, N is the number of wire grooves used for single cutting on the same roller, and A is a wire groove depth correction coefficient.

[0010] Preferably, in the above processing method, the value range of the wire groove depth correction coefficient A is 0.03-0.09.

[0011] Preferably, in the above processing method, the wire groove spacing between the wire grooves on the same roller is the same.

[0012] The wire groove spacing of the wire exit roller is equal to the wire groove spacing of the wire entry roller.

[0013] Preferably, in the above processing method, the wire groove spacing of the wire entry roller and the wire groove spacing of the wire exit roller are both α;

[0014] N = L / α;

[0015] Wherein, L is the length of the crystal bar to be cut.

[0016] Preferably, in the above processing method, the number of wire grooves N used for single cutting on the same roller ranges from 50 to 200.

[0017] Preferably, in the above processing method, the wire groove depth on the wire exit roller gradually decreases in the winding direction of the cutting wire;

[0018] The wire groove depth on the wire entry roller gradually decreases in the direction of the cutting wire.

[0019] Preferably, in the above processing method, in the cross section perpendicular to the axis direction of the cylindrical roller body, the wire exit roller and the wire entry roller each have at least N wire grooves;

[0020] Wherein, for the same section of cutting wire, the depth of the i+1th wire groove of the wire exit roller is less than the depth of the ith wire groove of the wire entry roller, and the depth of the ith wire groove of the wire entry roller is equal to the depth of the ith wire groove of the wire exit roller; i≤N.

[0021] The application also proposes a crystal bar cutting device, the cutting device comprising:

[0022] The roller assembly of any one of the above, the roller assembly comprising: a wire exit roller and a wire entry roller;

[0023] The cutting wire wound on the wire grooves of the wire exit roller and the wire entry roller.

[0024] Preferably, in the cutting device, in the cutting device, for the same section of cutting wire, the relationship between the wire groove depth of the wire exit roller and the wire groove depth of the wire entry roller satisfies:

[0025] d1 = d2 - A*N;

[0026] Wherein, d1 is the wire groove depth of the wire exit roller, d2 is the wire groove depth of the wire entry roller, N is the number of wire grooves used for single cutting, and A is the wire groove depth correction coefficient.

[0027] From the above, the application provides a processing method of a roller assembly and a crystal bar cutting device. The roller assembly comprises an outgoing roller and an incoming roller. The processing method of the roller assembly comprises the following steps: providing two cylindrical roller bodies for preparing the outgoing roller and the incoming roller respectively; forming a winding groove on the side surface of the roller body to form the outgoing roller and the incoming roller; and the depth of the winding groove of the outgoing roller is less than the depth of the winding groove of the incoming roller corresponding to the same cutting line. In the application, the depth of the winding groove of the outgoing roller corresponding to the same cutting line is less than the depth of the winding groove of the incoming roller when the winding groove is formed, so that the cutting depth of the outgoing end cutting line and the incoming end cutting line on the crystal bar is the same, and the wafer warping difference caused by the different cutting depths of the outgoing end cutting line and the incoming end cutting line is reduced, so that the wafer warping of the outgoing end and the incoming end is consistent. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of the provided drawings.

[0029] The structures, proportions, sizes, etc. shown in the drawings of the present specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not define the limiting conditions for the implementation of the present application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, which does not affect the effects and purposes that can be achieved by the present application, should still fall within the scope of the technical content disclosed by the present application.

[0030] Figure 1 It is a schematic diagram of the principle of multi-wire cutting of a crystal bar;

[0031] Figure 2 It is a schematic diagram of the wire diameter of the outgoing end cutting line and the incoming end cutting line before and after cutting and the cutting depth of the cutting line;

[0032] Figure 3 It is a flowchart of a processing method of a roller assembly according to an embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the wire diameter of the outgoing end cutting line and the incoming end cutting line before and after cutting and the cutting depth of the cutting line in the embodiment;

[0034] Figure 5 It is a schematic diagram of the winding groove spacing of the outgoing roller and the winding groove spacing of the incoming roller;

[0035] Figure 6 This is a flowchart illustrating another method for processing a roller assembly according to an embodiment of this application. Detailed Implementation

[0036] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0037] refer to Figure 1 , Figure 1 This is a schematic diagram illustrating the principle of multi-wire cutting of crystal rods. For clarity, the diagram is... Figure 1 The image only shows a portion of the cutting line 2 located above the roller assembly 1; the portion of the cutting line 2 winding below the roller assembly 1 is not shown. Current wafer cutting primarily uses multi-wire cutting, which, based on the material removal principle, is divided into free abrasive multi-wire cutting and bonded abrasive multi-wire cutting. Both free abrasive multi-wire cutting and bonded abrasive multi-wire cutting require the use of the roller assembly 1, which includes an output roller 11 and an input roller 12. The cutting principle of free abrasive multi-wire cutting is that a parallel mesh of high-speed moving cutting lines 2 carries cutting slurry containing diamond particles to the cutting area. The abrasive particles roll and scrape on the surface of the crystal rod 3, causing cracks on the surface of the crystal rod 3. The extension of these cracks removes the material. Bonded abrasive multi-wire cutting uses high-speed movement of the cutting lines 2, with diamond particles bonded to their surface, to grind the surface of the crystal rod 3, causing cracks and breakage, thus achieving the purpose of slicing.

[0038] The roller assembly 1 is the carrier of the cutting wires 2 in the multi-wire cutting machine and is the most important rotating component in the machine. It is generally composed of steel with a low coefficient of thermal expansion and a resin coating. The resin surface of the roller assembly 1 is grooved, and the resulting winding grooves 4 provide a track for the high-speed rotation of the cutting wires 2. Generally, each winding groove 4 on the roller assembly 1 has the same shape, angle, depth, and spacing to ensure that the cut wafers have the same thickness and warpage. However, in actual multi-wire cutting, taking free abrasive cutting as an example: the cutting wires 2 participate in the cutting, and their surface is gradually scraped and ground by diamond particles. The wire diameter of the cutting wires 2 becomes thinner and thinner, and the depth to which the cutting wires 2 cut the crystal is not consistent at the inlet and outlet ends.

[0039] refer to Figure 2 , Figure 2Fig. 1 is a schematic diagram of the wire diameter of the cutting line at the wire-out end and the wire-in end and the cutting depth of the cutting line before and after cutting. The depth of the wire groove 4 of the wire-out roller 11 is d a , the depth of the wire groove 4 of the wire-in roller 12 is d b , and the depth d a of the wire groove 4 of the wire-out roller 11 is equal to the depth d b of the wire groove 4 of the wire-in roller 12. The height difference between the highest point of the wire-out end cutting line and the highest point of the wire-in end cutting line is d3, the wire diameter of the wire-out end cutting line is β a , the wire diameter of the wire-in end cutting line is β b , and α a is the distance between the centers of two adjacent cutting lines 2. During the cutting process, the wire diameter of the cutting line 2 decreases with the increase of the cutting depth.

[0040] During the cutting process, the cutting line 2 gradually wears from the wire-in end to the wire-out end, and the relative position of the cutting line 2 to the crystal bar 3 is also different (when the cutting depth of the wire-in end is 20 mm, due to the wear of the cutting line 2, the actual cutting depth of the wire-out end is < 20 mm, and the cutting depth is taken as the origin of the contact point between the cutting line and the crystal bar 3, and the vertical line network direction). The crystal bar 3 moves downward at a variable speed (referred to as the feed speed, which changes with the cutting depth) during the cutting process, and the feed speeds of the wire-in end and the wire-out end at the same cutting depth are different, thus causing the differences in the wafer warping of the wire-in end and the wire-out end. As the yield of wafers increases, the length of the crystal bar 3 cut at one time gradually increases, the wear of the cutting line 2 from the wire-in end to the wire-out end increases, the wire diameter changes more obviously, and the wafer warping differences of the wire-in end (the cutting line 2 cuts first) and the wire-out end (the cutting line 2 cuts later) also become more obvious.

[0041] As the process of converting the crystal bar 3 into wafers, the multi-wire cutting plays a decisive role in the geometric characteristic parameters such as the wafer warping and bending after cutting, which directly affect the subsequent wafer grinding process and the qualification rate of the final product. Therefore, how to control the consistency of the wafer thickness and warping after cutting is of great value.

[0042] In the multi-wire cutting process, the cutting wires 2 in the wire grooves 4 reciprocate in the crystal bar 3 to cut the crystal bar 3. The highest point of the cutting wire 2 first contacts the crystal bar 3. However, as the cutting wire 2 continuously wears out during the cutting process, the diameter of the cutting wire 2 continuously decreases. In the case that the spacing between the wire grooves 4 of the wire-out roller 11 and the wire-in roller 12 is the same, the spacing between the cutting wires 2 is small, the cutting wire 2 moves to the wire-out end after wearing out, the spacing between the cutting wires 2 increases, and the position of the highest point of the cutting wire 2 in the wire groove 4 changes (as the diameter of the cutting wire 2 decreases, the highest point of the cutting wire 2 in the wire groove 4 moves downward). During cutting, the cutting speed (feed speed) continuously changes, the different cutting depths of the wire-in and wire-out ends cause the cutting speeds of the wire-in and wire-out ends to be different, and finally cause the warping difference of the wafers cut by the wire-in and wire-out ends. As the thickness of the crystal bar 3 increases in a single cutting, the change of the diameter of the cutting wire 2 increases, and the wafer warping difference of the wire-in and wire-out ends also increases.

[0043] Based on the above problems, the application provides a roller assembly processing method and a crystal bar cutting device. In the roller assembly 1 processing method, when the wire grooves 4 are formed, the depth of the wire groove 4 of the wire-out roller 11 corresponding to the same cutting wire 2 is less than the depth of the wire groove 4 of the wire-in roller 12, so that the cutting depth of the cutting wire 2 at the wire-in end and the cutting wire 2 at the wire-out end in the crystal bar 3 is the same. Therefore, the wafer warping difference caused by the different cutting depths of the cutting wire 2 at the wire-in end and the cutting wire 2 at the wire-out end can be reduced, and the wafer warping of the wire-out end and the wafer warping of the wire-in end formed by cutting can be kept consistent.

[0044] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below with reference to the drawings and specific embodiments.

[0045] Reference Figure 3 , Figure 3 The flowchart of the roller assembly processing method of the embodiment of the application is a roller assembly 1 processing method, which comprises the following steps.

[0046] Two cylindrical roller bodies are provided for preparing the wire-out roller 11 and the wire-in roller 12, respectively.

[0047] Wire grooves 4 are formed on the side surfaces of the roller bodies to form the wire-out roller 11 and the wire-in roller 12.

[0048] For the same cutting wire 2, the depth of the wire groove 4 of the wire-out roller 11 is less than the depth of the wire groove 4 of the wire-in roller 12.

[0049] Reference Figure 4 , Figure 4 As shown in the schematic diagram of the wire diameter of the cutting line at the wire-out end and the wire-in end and the cutting depth of the cutting line before and after cutting in the embodiment, based on the above, the application provides a processing method of a roller assembly 1, the roller assembly 1 comprising the wire-out roller 11 and the wire-in roller 12, and the formation of the roller assembly 1 comprises the following steps: providing two cylindrical roller bodies, the cylindrical roller bodies are generally formed by coating resin on steel materials with low expansion coefficient, a winding groove 4 is formed on the side surface of the cylindrical roller body to form the wire-out roller 11 and the wire-in roller 12, wherein the appearance of the winding groove 4 is in the shape of an inverted triangle or an inverted trapezoid, there is no fixed requirement for the appearance of the winding groove 4, but the depth d1 of the winding groove 4 of the wire-out roller 11 is less than the depth d2 of the winding groove 4 of the wire-in roller 12 corresponding to the same section of the cutting line 2, and the difference d4 between the depth d1 of the winding groove 4 of the wire-out roller 11 and the depth d2 of the winding groove 4 of the wire-in roller 12. There are a plurality of parallel cutting lines 2 between the wire-out roller 11 and the wire-in roller 12, and the plurality of parallel cutting lines 2 form a cutting net, and the same section of the cutting line refers to any one of the cutting net. The depth of the winding groove 4 of the wire-out roller 11 corresponding to the same section of the cutting line 2 is less than the depth of the winding groove 4 of the wire-in roller 12, which can make the cutting-in depth of the cutting line 2 at the wire-in end and the cutting line 2 at the wire-out end the same, thereby reducing the wafer warping difference caused by the different cutting-in depths of the cutting line 2 at the wire-in end and the cutting line 2 at the wire-out end, so that the warping at the wire-out end and the warping at the wire-in end of the wafer formed by cutting are consistent.

[0050] In the above processing method, for the same section of the cutting line 2, the relationship between the depth of the winding groove 4 of the wire-out roller 11 and the depth of the winding groove 4 of the wire-in roller 12 satisfies:

[0051] d1=d2-A*N (1)

[0052] wherein d1 is the depth of the winding groove 4 of the wire-out roller 11, d2 is the depth of the winding groove 4 of the wire-in roller 12, N is the number of winding grooves used for single cutting on the same roller, and A is a winding groove depth correction coefficient.

[0053] As can be seen from the above, in the processing method, the depth of the winding groove 4 of the outgoing roller 11 is smaller than the depth of the winding groove 4 of the incoming roller 12 corresponding to the same cutting line 2, and the relationship between the depth of the winding groove 4 of the outgoing roller 11 and the depth of the winding groove 4 of the incoming roller 12 satisfies formula (1). According to formula (1), the depth of the winding groove 4 of the outgoing roller 12 can be calculated according to the depth of the winding groove 4 of the incoming roller 11. The depth of the winding groove 4 of the outgoing roller 12 can be obtained by subtracting the product of the number of windings N used in a single cutting and the winding groove depth correction coefficient A from the depth of the winding groove 4 of the incoming roller 11.

[0054] In the processing method, the value range of the winding groove depth correction coefficient A is 0.03-0.09.

[0055] In the processing method, the winding groove depth correction coefficient A in formula (1) is a composite parameter, which is related to the appearance and angle of the winding groove 4 of the outgoing roller 11 and the incoming roller 12, and the wire wear of the cutting line 2. In the cutting process of the crystal bar 3, the wire diameter of the cutting line 2 decreases with the increase of the cutting depth, and the wire diameter wear Q of the cutting line 2 can be calculated by the outgoing end cutting line 2 and the incoming end cutting line 2. The relationship between the wire diameter wear Q of the cutting line 2 and the wire diameter β1 of the outgoing end cutting line 2 and the wire diameter β2 of the incoming end cutting line 2 is:

[0056] Q=β2-β1 (2)

[0057] Wherein, the wire wear of the cutting line 2 can be obtained according to the wire diameter wear Q of the cutting line 2 and experience judgment. And the winding groove depth correction coefficient A can be determined by the trigonometric function and the wire wear of the cutting line 2. The wire wear of the cutting line 2 needs to be determined by experience. The value range of the winding groove depth correction coefficient A is between 0.03 and 0.09.

[0058] In the processing method, the spacing between the winding grooves 4 on the same roller is the same.

[0059] The spacing of the winding grooves of the outgoing roller 11 is equal to the spacing of the winding grooves of the incoming roller 12.

[0060] Reference Figure 5 , Figure 5The schematic diagram of the winding groove spacing of the outgoing roller and the winding groove spacing of the incoming roller is shown in the figure, wherein α1 is the winding groove spacing of the outgoing roller 11, and α2 is the winding groove spacing of the incoming roller 12. In the above processing method, the winding groove spacing between the winding grooves 4 on the same roller is constant; the winding groove spacing α1 of the outgoing roller 11 is equal to the winding groove spacing α2 of the incoming roller 12; there are N winding grooves 4 on the outgoing roller 11 and the incoming roller 12; in the multi-wire cutting process, the cutting wire 2 is horizontally wound on the roller assembly 1, and the outgoing end and the incoming end of the cutting wire 2 need to be on the same axis, and the winding groove 4 of the outgoing roller 11 and the winding groove 4 of the incoming roller 12 need to be one-to-one corresponding, so that the cutting surface of the wafer is horizontal, and the warping degree of the wafer is reduced. In order to make the winding groove 4 of the outgoing roller 11 and the winding groove 4 of the incoming roller 12 one-to-one corresponding, the winding groove spacing α1 of the outgoing roller 11 needs to be equal to the winding groove spacing α2 of the incoming roller 12. In addition, the winding groove spacing of the same roller is constant. If the winding groove spacing of the same roller is different, the cutting wire 2 may jump due to the difference in spacing, which may easily increase the warping degree of the wafer formed by cutting.

[0061] In the above processing method, the winding groove spacing of the incoming roller and the winding groove spacing of the outgoing roller are both α;

[0062] N = L / α (3);

[0063] Wherein, L is the length of the wafer to be cut.

[0064] In the processing method, the depth of the winding groove 4 of the outgoing roller 11 can be calculated according to the depth of the winding groove 4 of the incoming roller 12 and formula (1), and formula (1) includes the number of winding grooves N used in single cutting. The formula (3) for calculating the number of winding grooves N used in single cutting includes the length L of the wafer 3 and the winding groove spacing α, so that the value of the number of winding grooves N used in single cutting can be determined according to the length L of the wafer and the winding groove spacing α.

[0065] In the above processing method, the value of the number of winding grooves N used in single cutting on the same roller is 50-200.

[0066] In the above processing method, the roller assembly 1 is processed by shallow groove processing, and the number N of winding grooves used for single cutting on the same roller is determined during the processing of the roller assembly 1. The value of N is limited by the length of the crystal bar 3, and the number N of winding grooves used for single cutting on the same roller can be calculated according to formula (3). However, during the cutting process of the crystal bar 3, the number N of winding grooves used for single cutting on the same roller affects the warping rate of the wafer formed by cutting. If the number N of winding grooves used for single cutting on the same roller is too large, the wire diameter of the cutting wire 2 changes more, and the warping rate of the wafer formed by cutting is also larger during the cutting process. That is, the value of the number N of winding grooves used for single cutting on the same roller has a certain range, and the value of the number N of winding grooves used for single cutting on the same roller is controlled between 50 and 200 in the current production process.

[0067] During the cutting process, if the winding groove spacing α is not increased, and only the length L of the crystal bar is increased, the number of single cutting slices is increased, and the wear amount of the cutting wire 2 is different when the same length of the cutting wire 2 cuts 100 slices and 200 slices. Therefore, the longer the length of the crystal bar 3 cut, the greater the change in the wire diameter of the cutting wire 2. Therefore, during the cutting process of the crystal bar 3, the value of the number N of winding grooves used for single cutting is changed by changing the length of the crystal bar 3 without changing the winding groove spacing α.

[0068] In the above processing method, the wire outlet roller 11 and the wire inlet roller 12 each have at least N winding grooves 4 in the cross section perpendicular to the axis direction of the cylindrical roller body.

[0069] For the same cutting wire, the depth of the i+1th winding groove of the wire outlet roller is less than the depth of the ith winding groove of the wire inlet roller, and the depth of the ith winding groove of the wire inlet roller is equal to the depth of the ith winding groove of the wire outlet roller; i≤N.

[0070] In the processing method, the wire outlet roller 11 and the wire inlet roller 12 each have at least N wire winding grooves 4 in the cross section perpendicular to the axis direction of the cylindrical roller body. During the cutting of the crystal bar 3 by the cutting wire 2, the diameter of the cutting wire 2 changes with the cutting depth, and for the same section of the cutting wire 2, the depth of the i+1th wire winding groove 4 of the wire outlet roller 11 is smaller than the depth of the ith wire winding groove 4 of the wire inlet roller 12, and during the movement of the cutting wire 2 on the i-1th wire winding groove 4 of the wire outlet roller 11 to the ith wire winding groove 4 of the wire inlet roller 12, the cutting wire 2 does not cut the crystal bar 3, i.e. the diameter of the cutting wire 2 does not change, so the depth of the ith wire winding groove 4 of the wire inlet roller 12 is equal to the depth of the ith wire winding groove 4 of the wire outlet roller 11, and the value of i is less than or equal to the number N of wire winding grooves used for single cutting on the same roller.

[0071] In the above processing method, the depth of the wire winding groove 4 on the wire outlet roller 11 gradually decreases in the winding direction of the cutting wire 2;

[0072] The depth of the wire winding groove 4 on the wire inlet roller 12 gradually decreases in the direction of the cutting wire 2.

[0073] In the processing method, the depth of the wire winding groove 4 of the wire outlet roller 11 and the wire inlet roller 12 gradually decreases in the winding direction of the cutting wire 2, and the depth of the ith wire winding groove of the wire inlet roller is equal to the depth of the ith wire winding groove of the wire outlet roller, and for the same section of the cutting wire 2, corresponding to the ith wire winding groove 4 of the wire inlet roller 12 and the i+1th wire winding groove 4 of the wire outlet roller 11, the depth of the i+1th wire winding groove 4 of the wire outlet roller 11 can be calculated according to the depth of the ith wire winding groove 4 of the wire inlet roller 12, and the method calculated in this way shows that the depth of the wire winding groove 4 on the same roller gradually decreases, and the direction of the decrease is the winding direction of the cutting wire 2.

[0074] Based on the above processing method, the processing method provided by the embodiment of the application is further described below in combination with a specific process flow chart.

[0075] Reference Figure 6 , Figure 6A flow chart of another processing method of the roller assembly is shown in FIG. 1, which is a flow chart of specific steps of the processing method. Based on the formula (1), the specific steps of processing the roller assembly 1 by controlling the depth of the wire slot 4 of the outgoing roller 11 and the incoming roller 12 include:

[0076] Step S11: Measure the diameter β2 of the cutting wire 2 at the incoming end and the diameter β1 of the cutting wire 2 at the outgoing end, calculate the diameter wear Q of the cutting wire 2, and determine the wear of the cutting wire 2 based on the diameter wear Q of the cutting wire 2.

[0077] Step S12: Determine the value of the wire slot depth correction coefficient A based on the wear of the cutting wire 2, the topography and angle of the wire slot 4.

[0078] Step S13: Calculate the number of wire slots N used in a single cutting according to the length L of the crystal bar to be cut, the wire slot spacing α, and the formula (3).

[0079] Step S14: Obtain the depth d1 of the wire slot 4 of the outgoing roller 11 according to the depth d2 of the wire slot 4 of the incoming roller 12, the number of wire slots N used in a single cutting, the wire slot depth correction coefficient A, and the formula (1).

[0080] Step S15: Determine the depth d1 of the wire slot 4 of the outgoing roller 11 and the depth d2 of the wire slot 4 of the incoming roller 12, and groove the roller body so that the groove depth of the wire slot 4 on the same roller decreases in the first direction.

[0081] After the roller assembly 1 is processed according to the above method, the roller assembly 1 is installed on a multi-wire cutting machine, the crystal bar 3 is wound on the roller assembly 1, and the cutting of the crystal bar 3 begins. The cutting techniques using the roller assembly 1 include but are not limited to free abrasive multi-wire cutting technology and fixed abrasive multi-wire cutting technology. The sizes of the crystal bar suitable for the cutting techniques using the roller assembly 1 include but are not limited to 2-inch, 3-inch, 4-inch, 6-inch, and 8-inch crystal bars.

[0082] Based on the above processing method, another specific embodiment and a control group formed in contrast thereto are proposed. The depth, angle, and topography of the wire slot 4 of the outgoing roller 11 of the control group are the same as those of the wire slot 4 of the incoming roller 12, specifically:

[0083] Based on the above processing method, taking the cutting of a 6-inch silicon carbide crystal rod as an example. The spacing of the winding grooves used for cutting is set to α3 = 670 μm, and the length of the silicon carbide crystal rod is L1 = 67 mm. Therefore, the number of winding grooves used in a single cut is N1 = 67 * 1000 / 670 = 100 (100 slices per cut). The diameter of the cutting wire used for cutting the silicon carbide crystal rod is 160 μm. After use, the diameter of the cutting wire is measured to be 155 μm. Therefore, the change in the diameter of the cutting wire is Q = 160 - 155 = 5 μm.

[0084] The winding groove 4 has an isosceles triangle shape and a grooving angle of 60°. The winding groove depth correction coefficient A is determined to be 0.075.

[0085] The number of winding grooves used in a single cut is N=100, and the depth d of the winding groove 4 of the input roller 12 is... 22 =350μm, the depth d of the winding groove 4 of the output roller 11 11 =d2-A*N=342.5μm;

[0086] After the silicon carbide crystal rod is cut, the average warp value of the first 5 silicon carbide wafers at the input end is E1=32.6μm, the average warp value of the 5 silicon carbide wafers at the output end is E2=26.4μm, and the warp difference value of the wafers at the input and output ends is E0=6.2μm.

[0087] In the control group:

[0088] A normally cut 6-inch silicon carbide crystal rod, the length of which is... =6700μm, the slot spacing of the winding groove used is 6700μm. =670μm, the depth of the winding groove 4 = =350μm is a fixed value, and the number of grooves used in a single cut is... =100, the average bending value of the first 5 silicon carbide wafers at the wire input end after the silicon carbide crystal rod is cut. =34.1μm, the average bending value of the five silicon carbide wafers at the output end =18.5μm, warpage difference between input and output line ends of the chip =15.6μm>10μm.

[0089] Table 1: Parameters for the Example and Control Groups

[0090]

[0091] As shown in Table 1, in the embodiment, the depth of the wire groove 4 of the outgoing roller 11 is changed by formula (1) without changing other conditions, and the depth of the wire groove 4 of the outgoing roller 11 in the control group is set as a fixed value. Through comparison of the two groups, it is found that the difference value E0 of the warping degree of the outgoing and incoming end wafers in the embodiment is 6.2 μm, the difference value of the warping degree of the outgoing and incoming end wafers in the control group is 15.6 μm, the difference value of the warping degree of the outgoing and incoming end wafers in the control group is greater than 10 μm, and the difference value E0 of the warping degree of the outgoing and incoming end wafers in the embodiment is less than 10 μm. Therefore, when the roller assembly 1 formed by the processing method is used to cut the crystal bar 3, the difference between the bending and warping values of the outgoing and incoming end wafers is reduced from 0-20 μm to within 0-10 μm with other cutting parameters unchanged. The difference between the outgoing end warping and the incoming end warping of the cut wafers is reduced, and the warping degree is basically consistent. The difference between the outgoing end warping and the incoming end warping of the cut wafers is reduced, and the warping degree is basically consistent.

[0092] The application also provides a crystal bar cutting device, which comprises:

[0093] The roller assembly 1 comprises an outgoing roller 11 and an incoming roller 12.

[0094] The cutting wire 2 is wound on the wire groove 4 of the outgoing roller 11 and the wire groove 4 of the incoming roller 12.

[0095] In the cutting device, the roller assembly 1 and the cutting wire 2 wound on the roller assembly 1 are included, wherein the depth of the wire groove 4 of the outgoing roller 11 corresponding to the same section of the cutting wire 2 is less than the depth of the wire groove 4 of the incoming roller 12. By changing the depth of the wire groove 4 of the outgoing roller 11, the cutting depth of the cutting wire 2 at the outgoing end is equal to the cutting depth of the cutting wire 2 at the incoming end during the cutting process of the crystal bar cutting device, so as to reduce the warping degree of the wafers obtained by cutting.

[0096] In the cutting device, the depth of the wire groove 4 of the outgoing roller 11 and the depth of the wire groove 4 of the incoming roller 12 corresponding to the same section of the cutting wire 2 satisfy:

[0097] d1=d2-A*N (1)

[0098] wherein d1 is the depth of the wire groove 4 of the outgoing roller 11, d2 is the depth of the wire groove 4 of the incoming roller 12, N is the number of wire grooves used for single cutting on the same roller, and A is a wire groove depth correction coefficient.

[0099] ​The depth of the wire winding groove 4 of the outgoing roller 11 is calculated by formula (1) so that the depth of the wire winding groove 4 of the outgoing roller 11 and the depth of the wire winding groove 4 of the incoming roller 12 vary with the cutting depth of the cutting wire 2, thereby reducing the warping degree of the wafer formed by cutting.

[0100] Based on the above, the application provides a processing method of a roller assembly 1 and a crystal bar cutting device. In the processing method of the roller assembly 1, when the wire winding groove 4 is formed, the depth of the wire winding groove 4 of the outgoing roller 11 corresponding to the same cutting wire 2 is less than the depth of the wire winding groove 4 of the incoming roller 12, and the depth of the wire winding groove 4 gradually decreases on the same roller, so that the cutting depth of the incoming end cutting wire 2 and the outgoing end cutting wire 2 in the crystal bar 3 is the same. Therefore, the difference in the cutting depth of the incoming end cutting wire 2 and the outgoing end cutting wire 2 can be reduced. When the crystal bar 3 is cut by the roller assembly 1 formed by the processing method, under the condition that the remaining cutting parameters are constant, the difference between the bending and warping values of the outgoing end wafer and the incoming end wafer is reduced from 0-20 μm to within 0-10 μm. The outgoing end warping and the incoming end warping of the wafer formed by cutting are consistent.

[0101] In the description of the specification, each embodiment is described in a progressive, or parallel, or a combination of progressive and parallel manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between each embodiment can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0102] It should be noted that in the description of the present application, it should be understood that the drawings and the description of the embodiments are illustrative but not limiting. The same reference numerals in the embodiments throughout the specification indicate the same structure. In addition, for the purpose of understanding and easy description, the thickness of some layers, films, panels, regions, etc. may be exaggerated in the drawings. It can also be understood that when an element such as a layer, film, region or substrate is referred to as "on" another element, the element can be directly on the other element or there can be an intermediate element. In addition, "on" means positioning an element on another element or below another element, but not essentially on the upper side of another element according to the direction of gravity.

[0103] The terms "upper", "lower", "top", "bottom", "inner", "outer" and the like, indicate an orientation or positional relationship based on the orientation or positional relationship as shown in the drawings, and are used only to facilitate description of the application and are not a declaration of or limitation on the position or orientation of the device or element in use or operation, and thus can not be construed as limiting the application. When one component is considered to be "connected" to another component, it can be directly connected to the other component or a component disposed therebetween can be present.

[0104] It is also to be noted that, as used in the specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Furthermore, the terms "comprising", "containing", or any other similar term are intended to encompass non-exclusive inclusions, such that a device or article that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such device or article. The term "comprising" does not exclude the presence of additional elements or steps.

[0105] The above description of disclosed embodiments provides enabling disclosure sufficient for a person of ordinary skill in the art to practice or use the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not to be limited to the embodiments set forth herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of machining a roller assembly, the roller assembly comprising an outgoing roller and an incoming roller, characterised in that, The processing method comprises: providing two cylindrical roller bodies for preparing the outgoing roller and the incoming roller respectively; forming wire grooves on the side surface of the roller body to form the outgoing roller and the incoming roller; wherein for the same section of cutting wire, the wire groove depth of the outgoing roller is less than the wire groove depth of the incoming roller, so that the cutting depth of the incoming end cutting wire and the outgoing end cutting wire to the crystal bar is the same; for the same section of cutting wire, the relationship between the wire groove depth of the outgoing roller and the wire groove depth of the incoming roller satisfies: ； wherein, is the wire slot depth of the outgoing roller, is the wire slot depth of the incoming roller, N is the number of wire slots used in a single cutting on the same roller, and A is a wire slot depth correction factor, the value of the wire slot depth correction factor A being in the range of 0.03 to 0.

09.

2. The method of claim 1, wherein the wire groove spacing between the wire grooves on the same roller is the same; the wire groove spacing of the outgoing roller is equal to the wire groove spacing of the incoming roller.

3. The method of claim 1 wherein, The wire groove spacing of the outgoing roller and the wire groove spacing of the incoming roller are both α; ; wherein L is the length of the crystal bar to be cut.

4. The method of claim 3, wherein The value range of the number N of wire grooves used for single cutting on the same roller is 50-200.

5. The method of claim 1 wherein, The wire groove depth on the outgoing roller gradually decreases in the winding direction of the cutting wire; The wire groove depth on the incoming roller gradually decreases in the direction of the cutting wire.

6. The method of claim 5, wherein, In the cross section perpendicular to the axis direction of the cylindrical roller body, the outgoing roller and the incoming roller each have at least N wire grooves; wherein, for the same segment of the cutting line, the depth of the i+1th winding groove of the out roller corresponding to the i th winding groove of the in roller and the i+1th winding groove of the out roller wound is less than the depth of the i th winding groove of the in roller, the depth of the i th winding groove of the in roller being equal to the depth of the i th winding groove of the out roller; i .

7. A crystal bar cutting apparatus characterized by comprising: The cutting device comprises: The roller assembly according to any one of claims 1-6, comprising: an outgoing roller and an incoming roller; The cutting wire wound on the wire grooves of the outgoing roller and the wire grooves of the incoming roller, so that the cutting depth of the incoming end cutting wire and the outgoing end cutting wire to the crystal bar is the same; In the cutting device, for the same section of cutting wire, the relationship between the wire groove depth of the outgoing roller and the wire groove depth of the incoming roller satisfies: ； wherein, is the wire slot depth of the outgoing roller, is the wire slot depth of the incoming roller, N is the number of wire slots used in a single cutting, and A is a wire slot depth correction factor, the value of the wire slot depth correction factor A being in the range of 0.03 to 0.09.

Images