Structure for measuring diameter and welding position of seed crystal

Abstract

The utility model provides a structure for measuring the diameter and the welding position of a seed crystal, which relates to the technical field of production of monocrystalline silicon by a czochralski method, and comprises a monocrystalline furnace body provided with a crucible for containing silicon liquid; the lifting head comprises a servo motor for lifting the seed crystal; the CCD camera is used for measuring the diameter of the seed crystal; and a single crystal furnace control system. Wherein the servo motor can record the position of a seed crystal and record the position of the seed crystal in a single crystal furnace control system; the input end of the single crystal furnace control system is connected with the output end of the CCD camera, and the output end of the single crystal furnace control system is connected with the control end of the servo motor. On one hand, the position of a new seed crystal is recorded through a single crystal furnace control system and a servo motor on a lifting head, and on the other hand, the diameter of the new seed crystal is measured by utilizing a CCD diameter measuring technology, so that the successful welding of the seed crystal is ensured through the combination of two modes of detecting the welding position and diameter of the seed crystal.

Description

Technical Field

[0001] The utility model relates to the technical field of producing single crystal silicon by Czochralski method, in particular to a structure for measuring the diameter of a seed crystal and a welding position. Background Art

[0002] In the current manufacturing process of single crystal silicon produced by the direct pulling method in the industry, seed crystal welding is basically carried out manually. Some manufacturers also determine whether welding is suitable by detecting the voltage change between the pulling head and the lower shaft after the seed crystal contacts the silicon liquid based on the conductivity of the molten silicon liquid. However, since the voltage digital change is small and is easily affected by interference signals, the judgment error of the voltage change is large, which can easily cause the problem of welding failure. Utility Model Content

[0003] In view of the above situation, the utility model provides a structure for measuring the diameter of the seed crystal and the welding position, aiming to solve the current technical problem of judging whether the welding is suitable by detecting the voltage change between the pulling head and the lower shaft after the seed crystal contacts the silicon liquid based on the conductivity of the molten silicon liquid. However, since the voltage digital change is small and is easily affected by interference signals, the judgment error of the voltage change is large, which can easily cause welding failure.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] The utility model provides a structure for measuring the diameter of a seed crystal and a welding position, which mainly includes:

[0006] A single crystal furnace body having a crucible for containing silicon liquid;

[0007] A clamping member, used for clamping a seed crystal;

[0008] The lifting head is connected to the clamping member; the lifting head is connected to a servo motor for lifting and lowering the seed crystal;

[0009] CCD camera, used to measure the diameter of the seed crystal;

[0010] Single crystal furnace control system;

[0011] Wherein: the servo motor can record the seed crystal position, and record the seed crystal position in the single crystal furnace control system; the input end of the single crystal furnace control system is connected to the output end of the CCD camera, and the output end is connected to the control end of the servo motor;

[0012] The clamping parts include:

[0013] The chuck body has a connection groove matching the seed crystal formed along its axial direction at its lower end; and

[0014] The limit plate is laterally plugged into the chuck body; the seed crystal is provided with a plug hole matching the limit plate;

[0015] The limiting mechanism is used to limit the lateral movement of the limiting plate.

[0016] In some embodiments of the present invention, the CCD camera is located outside the single crystal furnace.

[0017] In some embodiments of the present invention, the CCD camera is arranged horizontally.

[0018] In some embodiments of the present invention, the pulling head is transmission-connected to the servo motor via a pulling line.

[0019] In some embodiments of the present invention, the material of the chuck body includes graphite.

[0020] In some embodiments of the utility model, one end of the limiting plate is exposed from the chuck body and is provided with a through hole; the limiting mechanism includes:

[0021] A fixing block fixed on the outer wall of the chuck body;

[0022] The limiting rod is longitudinally plugged with the fixing block; the lower end of the limiting rod can be plugged with the through hole, and the top of the limiting rod is provided with a convex block.

[0023] In some embodiments of the present invention, the limiting plate has a wedge-shaped portion at one end facing the insertion hole, and an inner wall of one side of the insertion hole is inclined and can contact the inclined surface of the wedge-shaped portion.

[0024] In some embodiments of the present invention, a movably arranged pad block is further included, and the pad block is used to raise the protrusion.

[0025] In some embodiments of the present invention, the lower side wall of the protrusion shrinks inwardly.

[0026] In some embodiments of the present invention, the spacer is semi-annular.

[0027] The embodiments of the present invention have at least the following advantages or beneficial effects:

[0028] 1. The embodiment of the utility model records the position of the new seed crystal (i.e., the unused seed crystal) through the single crystal furnace control system and the servo motor on the pulling head, and uses CCD diameter measurement technology to measure the diameter of the new seed crystal, thereby ensuring the successful seed crystal welding by combining the two methods of detecting the seed crystal welding position and diameter.

[0029] Second, the disassembly and assembly of the seed crystal is facilitated by the setting of the clamping parts.

[0030] Other features and advantages of the present invention will be set forth in the following description, and in part will become apparent from the description, or will be understood by implementing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of the structure for measuring the seed crystal diameter and the fusion position provided in Example 1;

[0033] Figure 2 A schematic diagram of the structure of a graphite chuck provided in Example 2;

[0034] Figure 3 A schematic diagram of the structure of the cushion block provided in Example 2;

[0035] Figure 4 for Figure 3 Top view of the .

[0036] Icons: 1- single crystal furnace body, 11- sub-chamber, 12- crucible, 13- silicon liquid, 2- seed crystal, 31- graphite chuck, 311- chuck body, 312- limit plate, 313- connection groove, 314- socket, 315- through hole, 316- fixed block, 317- limit rod, 318- bump, 319- wedge-shaped part, 321- pad, 4- lifting head, 41- lifting wire, 5- CCD camera, A- seed crystal position one, B- lowest seed crystal position two in the last welding step. DETAILED DESCRIPTION

[0037] In the following, only some exemplary embodiments are briefly described. As those skilled in the art can appreciate, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present invention.

[0038] In the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0039] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0040] Example 1

[0041] Please refer to Figure 1 This embodiment provides a structure for measuring the seed crystal diameter and the welding position, which may mainly include: a single crystal furnace, a pulling head, a CCD camera 5 and a single crystal furnace control system (not shown in the figure).

[0042] The single crystal furnace comprises a single crystal furnace body 1 , in which a sub-chamber 11 and a crucible 12 for containing silicon liquid 13 are provided, and the sub-chamber 11 is located above the crucible 12 .

[0043] The lifting head includes a servo motor for lifting the seed crystal 2, a lifting wire 41 and a graphite chuck 31. The servo motor can record the position of the seed crystal 2 and record the position of the seed crystal 2 in the single crystal furnace control system. One end of the lifting wire 41 is connected to the output end of the servo motor, and the other end is connected to the graphite chuck 31. The graphite chuck 31 is a clamping member for clamping the seed crystal 2. In other embodiments, other clamping members can also be used to clamp the seed crystal 2.

[0044] The CCD camera 5 is used to measure the diameter of the seed crystal 2 . In this embodiment, preferably, the CCD camera 5 is horizontally arranged outside the single crystal furnace body 1 , and the CCD camera 5 is located between the sub-chamber 11 and the crucible 12 .

[0045] The single crystal furnace control system is a system that already exists and is used in conjunction with the single crystal furnace. In this embodiment, the input end of the single crystal furnace control system is connected to the output end of the CCD camera 5, and the output end is connected to the control end of the servo motor. The CCD camera 5 can transmit the diameter data of the seed crystal 2 measured by it to the single crystal furnace control system. The single crystal furnace control system determines whether the diameter of the measured seed crystal 2 meets the requirements by comparing the data with the preset value.

[0046] Using the structure for measuring the seed crystal diameter and the welding position, the seed crystal 2 can be welded as follows:

[0047] Step S1, standardizing the standard size of the seed crystal 2;

[0048] Step S2, welding the new seed crystal 2 (i.e., the unused seed crystal 2) according to the normal manual welding steps, and recording the welding position of the seed crystal 2 during the manual welding as the seed crystal position 1 by the single crystal furnace control system and the servo motor; and automatically recording the lowest seed crystal position 2 of the last welding step by the single crystal furnace control system and the servo motor;

[0049] Step S3, when the temperature of the silicon liquid 13 in the crucible 12 reaches the melting temperature, the single crystal furnace control system lowers the seed crystal 2 to the seed crystal position 1 recorded in step S2 through the servo motor;

[0050] Step S4, after the seed crystal 2 is lowered to the seed crystal position 1, the diameter of the seed crystal 2 is measured by the CCD camera 5 within 1 minute. If the diameter of the seed crystal 2 is within the required range, the single crystal furnace control system determines that this position (i.e., the seed crystal position 1) is the welding position; if the diameter of the seed crystal 2 is not within the required range, the seed crystal 2 is continued to be lowered to a position 3mm lower than the lowest seed crystal position 2 of the previous welding step for welding.

[0051] It should be noted that in step S4, when the diameter of the seed crystal 2 is not within the required range, the seed crystal 2 is further lowered to a position 3 mm lower than the lowest seed crystal position in the previous welding step for welding, wherein "3 mm" is obtained by the inventor based on actual operation experience.

[0052] In combination with the above content, it can be seen that in this embodiment, on the one hand, the position of the new seed crystal 2 (i.e., the unused seed crystal 2) is recorded by the single crystal furnace control system and the servo motor on the pulling head, and on the other hand, the diameter of the new seed crystal 2 is measured by using CCD diameter measurement technology, thereby ensuring the successful welding of the seed crystal 2 by combining these two methods of detecting the welding position and diameter of the seed crystal 2.

[0053] This embodiment helps to improve the automation level of single crystal pulling, and can reduce the probability of crystal pulling failure after welding caused by untimely manual operation and large errors in voltage change judgment.

[0054] Example 2

[0055] This embodiment is a specific implementation of the graphite chuck 31 of Embodiment 1.

[0056] Please refer to Figure 1 to Figure 4 In this embodiment, the graphite chuck 31 includes: a chuck body 311, a limit plate 312 laterally plugged into the chuck body 311, and a limit assembly for limiting the lateral movement of the limit plate 312; a connecting groove 313 matching the seed crystal 2 is provided at the lower end of the chuck body 311 along its axial direction; a socket 314 matching the limit plate 312 is provided on the seed crystal 2, and the right end of the limit plate 312 is exposed from the chuck body 311 and is provided with a through hole 315.

[0057] The limiting assembly includes a fixing block 316 and a limiting rod 317; the fixing block 316 is fixed on the outer wall of the chuck body 311; the limiting rod 317 is longitudinally plugged into the fixing block 316, the lower end of the limiting rod 317 can be plugged into the through hole 315, and the top of the limiting rod 317 has a protrusion 318.

[0058] When connecting the graphite chuck 31 and the seed crystal 2, the seed crystal 2 can be first inserted from bottom to top into the connecting groove 313 at the lower end of the chuck body 311, and then the limit plate 312 can be inserted into the insertion hole 314 of the seed crystal 2 to limit the longitudinal movement of the seed crystal 2 relative to the graphite chuck 31, and then the lower end of the limit rod can be plugged into the through hole 315 to limit the movement of the limit plate 312.

[0059] When the graphite chuck 31 and the seed crystal 2 need to be separated, the temperature of the graphite chuck 31 is often still very high. At this time, the limit rod 317 can be moved upward with the help of an external tool. After the limit rod 317 is separated from the limit plate 312, the limit plate 312 and the seed crystal 2 can be separated, and then the seed crystal 2 can be pulled out downward. In the process of separating the graphite chuck 31 and the seed crystal 2, the operator is not easily burned by the graphite chuck 31 because he does not need to directly contact the high-temperature graphite chuck 31 throughout the whole process.

[0060] In a specific implementation scenario, the limit plate 312 has a wedge-shaped portion 319 at one end facing the socket 314, and the inner wall of one side of the socket 314 is inclined and can contact the inclined surface of the wedge-shaped portion 319. In this way, when it is necessary to separate the graphite chuck 31 and the seed crystal 2, the seed crystal 2 can be directly pulled downward after separating the limit rod 317 and the limit plate 312; in the process of pulling the seed crystal 2 downward, the seed crystal 2 can push the limit plate 312.

[0061] In a specific implementation scenario, the graphite chuck 31 also includes a movable pad 321, which is semi-circular in shape, and the lower side wall of the protrusion 318 is retracted inward. When it is necessary to separate the limit rod 317 and the limit plate 312, the pad can be pushed between the protrusion 318 and the fixed block 316 to raise the protrusion 318, so that the limit rod 317 moves up and separates from the limit plate 312.

[0062] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. In the absence of conflicts, the embodiments of the present application and the features in the embodiments may be combined with each other at will. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A structure for measuring seed crystal diameter and welding position, characterized in that: include: A single crystal furnace body having a crucible for containing silicon liquid; A clamping member, used for clamping a seed crystal; A lifting head is connected to the clamping member; the lifting head is transmission-connected to a servo motor, and the servo motor is used to lift the seed crystal; A CCD camera is used to measure the diameter of the seed crystal; Single crystal furnace control system; Wherein: the servo motor can record the seed crystal position, and record the seed crystal position in the single crystal furnace control system; the input end of the single crystal furnace control system is connected to the output end of the CCD camera, and the output end is connected to the control end of the servo motor; The clamping member comprises: A chuck body, the lower end of which is provided with a connection groove along its axial direction that matches the seed crystal; and A limit plate is laterally plugged into the chuck body; a plug hole matching the limit plate is provided on the seed crystal; The limiting mechanism is used to limit the lateral movement of the limiting plate.

2. The structure for measuring the seed crystal diameter and the welding position according to claim 1, characterized in that: The CCD camera is located outside the single crystal furnace.

3. The structure for measuring the seed crystal diameter and the welding position according to claim 1, characterized in that: The CCD camera is arranged horizontally.

4. The structure for measuring the seed crystal diameter and the welding position according to claim 1, characterized in that: The pulling head is transmission-connected to the servo motor via a pulling wire.

5. The structure for measuring the seed crystal diameter and the welding position according to claim 1, characterized in that: The material of the chuck body includes graphite.

6. The structure for measuring the seed crystal diameter and the fusion position according to any one of claims 1 to 5, characterized in that: One end of the limiting plate is exposed from the chuck body and is provided with a through hole; the limiting mechanism comprises: A fixing block, fixed on the outer wall of the chuck body; The limiting rod is longitudinally plugged into the fixing block; the lower end of the limiting rod can be plugged into the through hole, and the top of the limiting rod is provided with a protrusion.

7. The structure for measuring the seed crystal diameter and the fusion position according to claim 6, characterized in that: The end of the limiting plate facing the insertion hole has a wedge-shaped portion, and an inner wall of one side of the insertion hole is inclined and can contact the inclined surface of the wedge-shaped portion.

8. The structure for measuring the seed crystal diameter and the fusion position according to claim 6, characterized in that: It also includes a movably arranged pad block, which is used to raise the protrusion.

9. The structure for measuring the seed crystal diameter and the fusion position according to claim 8, characterized in that: The lower side wall of the projection shrinks inwardly.

10. The structure for measuring the seed crystal diameter and the fusion position according to claim 8, characterized in that: The cushion block is semi-annular.

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