Staggered groove measurement tool for reducing silicon wafer TTV abnormal occurrence rate
By designing a tool for measuring the distance between the wrong slots, the problem of TTV abnormality of silicon wafer caused by inaccurate measurement in the prior art is solved, and higher measurement accuracy and silicon wafer quality are achieved.
Patent Information
- Application Number
- CN202421984947.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-15
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-08-15
AI Technical Summary
The prior art is difficult to accurately measure the distance between the wrong slots, resulting in a high incidence of TTV abnormalities in silicon wafers, affecting the quality and production process of silicon wafers.
A wrong groove measurement tool is designed, including a tool body, a positioning surface, a first extension arm and a second extension arm. Through the cooperation of these components, the wrong groove distance can be accurately measured in three-dimensional space.
By accurately measuring the wrong slot distance, it can effectively reduce TTV abnormalities in silicon wafers, improve the quality of silicon wafers and the stability of production processes, reduce non-silicon costs and increase the A-level rate.
Smart Images
Figure CN223021163U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a misalignment measurement tooling, in particular to a misalignment measurement tooling for reducing the abnormal occurrence rate of the total thickness variation (TTV) of silicon wafers. Background Art
[0002] The slicing process is an important process for preparing solar silicon wafers. The cutting principle of solar silicon wafers is that a large number of diamond particles are carried on a rotating steel wire, and at the same time, the workbench position slowly descends. Since the hardness of diamond is greater than that of crystalline silicon (the Mohs hardness of crystalline silicon is 6.5, and the Mohs hardness of silicon carbide is 9.5), the silicon block is continuously ground by the edges of the diamond, playing a cutting role. The thickness difference (TTV) of different regions of a single sliced silicon wafer is a very important indicator to measure the quality of the silicon wafer. The existence of TTV wafers will affect the qualification rate of silicon wafers and the production process of solar cells, so more stringent requirements are put forward for the quality of silicon wafers. Among them, the thickness of the center point of the silicon wafer is used as the nominal thickness of the silicon wafer, and the difference between the maximum thickness and the minimum thickness among the thickness measurement values at 5 equally divided positions is called the total thickness variation TTV of the silicon wafer.
[0003] The cutting process of the silicon wafer is completed on the main roller. The steel wire winds on the main roller to form a uniform wire mesh with parallel and equally spaced lines, and moves forward and backward at a speed of 10 - 15 m / s to cut the silicon rod. However, as the cutting progresses, the diamond on the steel wire is worn to varying degrees, the ellipticity of the steel wire increases, and the sand-carrying capacity decreases. At the same time, the roundness of the diamond particles becomes larger, and the average sharpness decreases, resulting in a reduction in the cutting ability. Due to the change in wire diameter wear, the cutting process needs to be compensated by the grooving process. However, for the steel wire moving forward and backward at high speed, although there is a certain tension to tighten it, there is still a significant periodic jitter amplitude. The jitter amplitude is one of the main reasons for the current generation of TTV wafers. The silicon wafer thickness has a certain deviation range. For a 130-μm-thick silicon wafer, the deviation range is ±20 μm. Exceeding this range results in defective TTV thin and thick wafers. Fundamentally speaking, the generation of thin and thick wafers is caused by the jitter of the wire mesh due to various problems. One of the effective methods to reduce the periodic jitter amplitude is precise misalignment.
[0004] The diamond wire is densely wound on the main roller to form a wire mesh. To ensure the slicing quality, when forming the wire mesh, the diamond wire mesh needs to be arranged with staggered slots (instead of the wire mesh being perpendicular to the axis of the main roller), and the number of staggered slots will affect the cutting performance of the slicing machine. In the current development process of slicing technology towards thinner wafers and finer wires, the influence of the distance between the staggered slots of the wire mesh on the cutting quality is becoming more and more obvious, and higher precision is required. Currently, there are mainly two types of methods for controlling the distance between the staggered slots when arranging the wire mesh: one is to count the number of slots, that is, to determine the distance between the staggered slots by multiplying the difference in the number of slots where the first diamond wire is located on the left and right main rollers by the slot pitch. However, this method has a large coplanarity error in the three-dimensional space for the first groove on the main roller; the other is to measure the distance, that is, to measure the distance from the first diamond wire on the left and right main rollers to the end face of the bearing box. However, this method has a greater deviation due to the difference in the distance from the first groove on the main roller to the end face of the main roller, as well as the precision problem of the mating taper surface of the main roller and the coplanarity (and perpendicular to the axis of the main roller) problem of the end face of the bearing box (more obvious for old machines + old main rollers). The difference in the number of staggered slots and the difference in the distance between the staggered slots define the distance between the staggered slots in the three-dimensional space, resulting in the actual distance between the staggered slots not being equal to the product of the number of staggered slots and the slot pitch. If the distance between the staggered slots in the three-dimensional space is too large, wiring abnormalities will occur; if the distance between the staggered slots in the three-dimensional space is too small, the periodic jitter amplitude of the steel wire will be large, and the probability of dense wire jumping will increase, and the TTV value of the silicon wafer will exceed the standard. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a misalignment measurement tooling that is easy to use and can accurately measure the misalignment distance to reduce the abnormal incidence rate of the TTV of the silicon wafer.
[0006] The technical solution adopted by the present invention is: the present invention includes a tooling body, one side of the tooling body has a positioning surface, the tooling body horizontally extends with a first extension arm and a second extension arm, the first extension arm and the second extension arm are arranged in parallel and both face the same side, the ends of the first extension arm and the second extension arm are aligned with each other, and both are provided with measurement scales. When measuring, the first extension arm and the second extension arm both pass through the first wire of the cutting wire mesh, and the positioning surface abuts against the cylindrical surface at the side end of the main roller during measurement.
[0007] Further, the positioning surface is a positioning plate formed on one side of the tooling body, and the positioning plate is vertically arranged.
[0008] Further, the upper end of the positioning plate is fixedly connected to one side of the tooling body by screws.
[0009] Further, the first extension arm and the second extension arm are symmetrically arranged on the tooling body.
[0010] Further, the first extension arm and the second extension arm are both detachably connected to the tooling body.
[0011] Further, the first extension arm and the second extension arm are threadedly connected to the tooling body.
[0012] Further, the first extension arm and the second extension arm are snap-connected to the tooling body.
[0013] Further, the cross-section of the tooling body is rectangular.
[0014] Further, a plurality of observation ports are formed in the tooling body.
[0015] Further, the observation ports are located above the first extension arm and the second extension arm.
[0016] The beneficial effects of the present utility model are as follows:
[0017] Compared with the deficiencies of the prior art, in the present utility model, through the positioning surface, the first extension arm and the second extension arm of the tooling, the normal line perpendicular to the axis of the main roller is found, and based on this normal line, the distance difference between the first cutting lines on the two main rollers is measured, realizing the accurate measurement of the stagger distance in three-dimensional space. Therefore, the stagger distance can be quickly and accurately measured by the stagger measurement tooling, which can effectively reduce the situation of stranded wires (large stagger distance) and dense jumper wires (small stagger distance) during cutting, and reduce the non-silicon cost and improve the A-grade rate of silicon wafers, making the present utility model have the advantages of being easy to use and capable of accurately measuring the stagger distance. Description of the Drawings
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model, and for those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.
[0019] Figure 1 is the schematic plan view of the present utility model;
[0020] Figure 2 is the schematic plan view of the tooling body and the positioning surface of the present utility model;
[0021] Figure 3 is the schematic plan view of the positioning surface of the present utility model;
[0022] Figure 4 is the measurement schematic diagram of the present utility model.
[0023] The reference numerals are as follows:
[0024] 1. Tooling body; 2. Positioning surface; 3. First extension arm; 4. Cutting wire mesh; 5. Second extension arm; 6. Measurement scale; 7. Main roller; 8. Observation port.
[0025] The realization, functional features and advantages of the present utility model will be further described in conjunction with the embodiments with reference to the accompanying drawings. Detailed implementation manners
[0026] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.
[0027] It should be noted that all directional indications in the embodiments of the present utility model, such as up, down, left, right, front, back, clockwise, counterclockwise, etc., are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly.
[0028] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.
[0029] As Figures 1 to 3 shown, in this embodiment, the present utility model includes a tooling body 1. One side of the tooling body 1 has a positioning surface 2. The tooling body 1 horizontally extends with a first extension arm 3 and a second extension arm 5. The first extension arm 3 and the second extension arm 5 are arranged in parallel and both face the same side. The ends of the first extension arm 3 and the second extension arm 5 are aligned, and both are provided with a measurement scale 6. The first extension arm 3 and the second extension arm 5 both pass through the first wire of the cutting wire mesh 4 during measurement. The positioning surface 2 abuts against the cylindrical surface at the side end of the main roller 7 during measurement.
[0030] It should be noted that as Figure 4As shown, the cutting process of the silicon wafer is completed on the main roller 7. The steel wire winds around the main roller 7 to form a uniform wire mesh with parallel and equidistant lines. Specifically, this structure includes two main rollers 7 arranged in parallel, and a cutting wire mesh 4 is arranged between the two main rollers 7; among them, the value M is the value of a single groove pitch.
[0031] When measuring the misalignment distance, as Figure 4 shown, invert the tooling body 1 on the two main rollers 7 so that the positioning surface 2 abuts against the cylindrical surface at the side end of the main roller 7; further, translate the tooling body 1 along the axial direction of the main shaft so that both the first extension arm 3 and the second extension arm 5 pass through the first wire of the cutting wire mesh 4, where the positioning surface 2 always abuts against the cylindrical surface at the side end of the main roller 7 during the translation process; further, read the measured values on the first extension arm 3 and the second extension arm 5, that is, the values A and B as shown in Figure 4 shown. The absolute value N of the difference between the two is the misalignment distance in three-dimensional space. Finally, adjust the number of grooves according to the process requirements (number of grooves added or subtracted = adjustment distance ÷ single groove pitch value, rounded to an integer).
[0032] For the convenience of explanation, take a silicon wafer with a thickness of 150 μm as an example. Its single groove pitch is 0.205 mm, and the required misalignment distance according to the process requirements is 0.8 mm to 1.0 mm;
[0033] Case 1: The measured values of the first extension arm 3 and the second extension arm 5 are 18.4 mm and 17.1 mm respectively. Then the misalignment distance is 1.3 mm. This misalignment distance is greater than the process requirements, so the number of misaligned grooves needs to be reduced, and two fewer grooves are misaligned (1.3 - 0.205 * 2 = 0.890 mm). The actual number of misaligned grooves is 0.890 ÷ 0.205 ≈ 4 grooves;
[0034] Case 2: The difference between the measured values of the first extension arm 3 and the second extension arm 5 is 0.7 mm. Then the misalignment distance is 0.7 mm. This misalignment distance is less than the process requirements, so the number of misaligned grooves needs to be increased, and one more groove is misaligned (0.7 + 0.205 * 1 = 0.905 mm). The actual number of misaligned grooves is 0.905 ÷ 0.205 ≈ 4 grooves.
[0035] Compared with the deficiencies of the prior art, in the present utility model, through the positioning surface 2, the first extension arm 3 and the second extension arm 5 of the tooling, the normal line perpendicular to the axis of the main roller 7 is found, and based on this normal line, the distance difference between the first cutting lines on the two main rollers 7 is measured, realizing the accurate measurement of the misalignment distance in three-dimensional space. Therefore, the misalignment distance can be quickly and accurately measured through the misalignment measurement tooling, which can effectively reduce the situation of wire twisting (large misalignment distance) and dense jumper wires during cutting (small misalignment distance), and reduce the non-silicon cost and improve the A-grade rate of the silicon wafer, making the present utility model have the advantages of being easy to use and being able to accurately measure the misalignment distance.
[0036] In some embodiments, the positioning surface 2 is a positioning plate formed on one side of the tooling body 1, and the positioning plate is vertically arranged; the upper end of the positioning plate is fixedly connected to one side of the tooling body 1 by screws. Specifically, during testing, the positioning surface 2 always abuts against the cylindrical surface at the side end of the main roller 7, and both the first extension arm 3 and the second extension arm 5 abut against the end faces of the two main rollers 7, so as to achieve accurate measurement of the stagger distance in three-dimensional space.
[0037] In some embodiments, the first extension arm 3 and the second extension arm 5 are symmetrically arranged on the tooling body 1; the first extension arm 3 and the second extension arm 5 are detachably connected to the tooling body 1; the first extension arm 3 and the second extension arm 5 are threadedly connected to the tooling body 1; the first extension arm 3 and the second extension arm 5 are snap-connected to the tooling body 1. Specifically, different specifications of extension arms can be replaced by disassembling the first extension arm 3 and the second extension arm 5 to meet different requirements in actual testing.
[0038] In some embodiments, the cross-section of the tooling body 1 is rectangular; a plurality of observation ports 8 are formed on the tooling body 1; the observation ports 8 are located above the first extension arm 3 and the second extension arm 5.
[0039] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made by using the description and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.
Claims
1. A misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers, characterized by: The tooling body (1) comprises a tooling body (1), one side of which is provided with a positioning surface (2), a first extension arm (3) and a second extension arm (5) extending horizontally from the tooling body (1), the first extension arm (3) and the second extension arm (5) being arranged in parallel and facing the same side, the ends of the first extension arm (3) and the second extension arm (5) being aligned with each other and both being provided with measurement scales (6), the first extension arm (3) and the second extension arm (5) both passing through the first line of the cutting wire net (4) during measurement, and the positioning surface (2) abutting against the cylindrical surface of the side end of the main roller (7) during measurement.
2. The misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 1, characterized in that: The positioning surface (2) is a positioning plate formed on one side of the tool body (1), and the positioning plate is arranged vertically.
3. The misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 2, characterized in that: The upper end of the positioning plate is fixedly connected to one side of the tool body (1) by means of screws.
4. The misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 1, characterized in that: The first extension arm (3) and the second extension arm (5) are symmetrically arranged on the tool body (1).
5. A misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 1 or 4, characterized in that: The first extension arm (3) and the second extension arm (5) can both be detachably connected to the tool body (1).
6. The misaligned slot measuring tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 5, characterized in that: The first extension arm (3) and the second extension arm (5) are threadedly connected to the tool body (1).
7. The misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 5, characterized in that: The first extension arm (3) and the second extension arm (5) are clamped on the tool body (1).
8. The misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 1, characterized in that: The cross section of the tool body (1) is rectangular.
9. A misaligned slot measurement tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 1 or 8, characterized in that: The tool body (1) is provided with a plurality of observation ports (8).
10. The misaligned slot measuring tool for reducing the occurrence rate of TTV abnormality of silicon wafers according to claim 9, characterized in that: The observation port (8) is located above the first extension arm (3) and the second extension arm (5).