Search

CN-121976288-A - Center-adjustable seed crystal pull rod, crystal pulling device and coaxiality adjusting method of center-adjustable seed crystal pull rod

CN121976288ACN 121976288 ACN121976288 ACN 121976288ACN-121976288-A

Abstract

An adjustable seed crystal pull rod relates to the technical field of semiconductor manufacturing, can radically correct rotation deviation and synchronously improve the reliability of dynamic sealing, thereby reducing crystal defects and improving equipment stability; the automatic lifting device comprises a base rod, wherein one end of the base rod is connected with an output end of a rotary lifting module, the other end of the base rod stretches into a furnace body, an adjustable connecting structure is arranged at the stretching end of the base rod, the structure comprises a connector, the connector is fixed at the end part of the base rod, an abutting surface is formed on the end face of the base rod, a mounting sleeve is sleeved outside the connector and connected with the connector, the mounting sleeve is provided with an axial mounting hole, the bottom of the mounting hole radially inwards extends to form a limit ring, three adjusting screw holes are uniformly distributed along the circumferential direction of the mounting sleeve, an adjusting jackscrew is arranged in the mounting sleeve, the end part of the jackscrew stretches into the mounting hole, a replacement pull rod is arranged in the mounting hole, an installation shaft matched with the mounting hole is arranged at the top of the replacement pull rod, the upper end face of the replacement pull rod abuts against the abutting surface, the side face of the replacement pull rod abuts against the side wall of the shaft, and the bottom of the replacement pull rod is a pull part.

Inventors

  • YANG HOURONG
  • ZHANG YONGGU
  • LUO CHEN

Assignees

  • 重庆右维科技有限公司

Dates

Publication Date
20260505
Application Date
20260317

Claims (10)

  1. 1. The adjustable seed crystal pull rod comprises a base rod (1), one end of the base rod (1) is used for being connected with an output end of a rotary lifting module, the other end of the base rod is used for being inserted into a furnace body of a single crystal furnace, and the adjustable seed crystal pull rod is characterized in that an adjustable connecting structure is arranged at the inserted end portion of the base rod (1), the adjustable connecting structure comprises a connector (101), the connector is fixed at the end portion of the base rod (1), an accurate abutting surface (103) is formed on the end face of the connector, a mounting sleeve (102) is sleeved outside the connector (101) and is in threaded connection with the connector (101), the mounting sleeve (102) is provided with an axial mounting hole, a limit ring (104) is formed at the bottom of the mounting hole in a radial inner extending mode, at least three adjusting screw holes are uniformly distributed in the circumferential direction of the mounting sleeve (102), the end portion of the adjusting screw (120) is inserted into the mounting hole, a replacement (107) is arranged in the mounting hole, a mounting shaft (108) matched with the mounting hole, the top of the mounting shaft (108) is arranged at the top of the mounting shaft (108), the mounting shaft (108) abuts against the side face of the mounting shaft (108), and the side face abuts against the side face of the side face (108), and the side face (108) abuts against the side face of the side face (108).
  2. 2. The seed crystal pull rod capable of aligning according to claim 1, wherein the base rod (1) and the connector (101) are connected through a conical surface centering structure, the conical surface centering structure comprises a conical cylinder (110) arranged on the connector (101), a connecting cylinder (113) sleeved outside the conical cylinder (110), the connecting cylinder (113) is fixedly connected with the base rod (1), and the seed crystal pull rod further comprises at least three aligning screws (121) which are uniformly distributed along the circumferential direction of the connecting cylinder (113), and the aligning screws (121) radially penetrate through the connecting cylinder (113) and enable the end parts of the aligning screws to be abutted against the outer conical surface of the conical cylinder (110).
  3. 3. The seed crystal pull rod capable of aligning according to claim 2, wherein at least two mounting lugs (111) are arranged on the upper end face of the conical barrel (110) at intervals, axial accommodating grooves (114) matched with the mounting lugs (111) are formed in corresponding positions on the inner side of the connecting barrel (113), locking pins are further arranged on the connecting barrel (113), and the locking pins penetrate through the connecting barrel (113) and then extend into locking holes (112) in the bottom end of the conical barrel (110).
  4. 4. A method for adjusting the coaxiality of a seed crystal pull rod, which is the adjustable core seed crystal pull rod as claimed in any one of claims 1 to 3, comprising the steps of: s1, a pre-installation step, namely placing an installation shaft (108) of the replacement pull rod (107) into an installation hole of the installation sleeve (102) to enable the upper end surface of the installation shaft to be in contact with the abutting surface (103), and primarily screwing the installation sleeve (102); S2, a detection reference establishment step, namely installing a high-precision calibration ring at a preset position of a crystal pulling part (109) or a rod body of the replacement pull rod (107), and installing the seed crystal pull rod on a calibration platform, wherein the calibration platform is provided with a driving unit for driving the seed crystal pull rod to rotate and at least two non-contact displacement sensors, and the sensors point to the outer cylindrical surface of the calibration ring; S3, a rotation detection step, namely driving the seed crystal pull rod to rotate at a constant speed, and collecting radial runout data of the calibration ring in the rotation process through the displacement sensor; S4, analyzing and adjusting, namely calculating the coaxiality deviation of the replacement pull rod (107) relative to the axis of the base rod (1) according to the radial runout data, and finely adjusting the radial position of the mounting shaft (108) by screwing the adjusting jackscrew (120) so as to correct the coaxiality deviation; s5, a verification and solidification step, namely repeating the rotation detection step and the analysis and adjustment step until the radial runout data meet the preset precision requirement, and finally locking the mounting sleeve (102) to finish calibration.
  5. 5. The method for adjusting the coaxiality of a seed rod according to claim 4, wherein in the step of performing the analysis adjustment in S4, if the coaxiality deviation cannot be corrected to the target range by adjusting the jack screw (120), a secondary adjustment is performed by loosening the lock pin between the joint head (101) and the base rod (1), fine-tuning the angle and position of the tapered cylinder (110) of the joint head (101) in the connecting cylinder (113) by screwing the calibration screw (121) to correct the reference axis of the end of the base rod (1), then re-locking the lock pin, and performing the rotation detection of the step S3 and the analysis adjustment of the step S4 again.
  6. 6. A single crystal pulling device integrated with a center-adjustable seed crystal pull rod comprises a frame (2), wherein the frame (2) is provided with a furnace body (3), a crucible (301) and a heating coil (302) are arranged in the furnace body (3), a cooling module (5) and a vacuum module (6) for cooling and vacuumizing the furnace body (3) are arranged outside the furnace body (3), a rotary lifting module (4) is arranged at the top of the frame (2) and above the furnace body (3), the upper end of a base rod (1) is connected to the output end of the rotary lifting module (4), the lower end of the base rod (1) extends downwards into the furnace body (3), and a center-adjustment system comprises a sensor detection module arranged on the rotary lifting module or the frame, the sensor detection module is used for detecting radial runout of the center-adjustable pull rod when the furnace body (3) is rotated, and is controlled to be in coaxial with the rotary lifting module and the sensor detection module, and the sensor detection module is connected with a feedback module to calculate the center-adjustable seed crystal pull rod (120) according to the electric deviation of the control screw.
  7. 7. The single crystal pulling apparatus incorporating a center-adjustable seed pull rod of claim 6, wherein the sensor detection module includes at least two laser displacement sensors directed in a non-contact manner to a predetermined calibration area on the shaft of the replacement pull rod (107) or a calibration ring mounted on the pull portion (109).
  8. 8. The single crystal pulling apparatus integrated with a seed crystal pulling rod according to claim 6 or 7, wherein the man-machine interaction interface of the control module is provided with a calibration mode, in which the screen dynamically displays the radial runout trajectory and the coaxiality deviation value when the seed crystal pulling rod rotates, and provides visual guidance of the direction and the screwing amount for an adjusting jackscrew (120) or a calibration screw (121) to be adjusted.
  9. 9. The single crystal pulling device integrated with the adjustable seed crystal pulling rod, as set forth in claim 6 or 7, characterized in that the rotary lifting module (4) comprises a lifting assembly (401) and a rotary assembly (402), the lifting assembly (401) comprises a screw sliding table (4010), a servo motor (4011) and a guide rail (4012) which are arranged on the frame (2), the rotary assembly (402) is arranged on the sliding table of the screw sliding table (4010) and driven by the screw to lift along the guide rail (4012), the rotary assembly (402) comprises a driving motor (4021), the output end of the driving motor (4021) is connected with the upper end of the base rod (1) through a magnetic current sealing assembly (4022), an organ sealing sleeve (7) is sleeved on the outer side of the base rod (1), and two ends of the organ sealing sleeve (7) are respectively connected with the furnace body (3) and the magnetic current sealing assembly (4022) through flanges.
  10. 10. The single crystal pulling device integrated with the aligning seed crystal pulling rod, as set forth in claim 9, is characterized in that a telescopic guide frame (701) is further arranged on the outer side of the organ sealing sleeve (7), one end of the telescopic guide frame (701) is fixed on the top of the furnace body (3), the telescopic guide frame (701) comprises a multi-section telescopic rod (702) arranged on two sides of the organ sealing sleeve (7), a plurality of fixing rings (703) are arranged on the multi-section telescopic rod (702) in the axial direction, and the organ sealing sleeve (7) is clamped in the fixing rings (703).

Description

Center-adjustable seed crystal pull rod, crystal pulling device and coaxiality adjusting method of center-adjustable seed crystal pull rod Technical Field The invention relates to the technical field of semiconductor production devices, in particular to an adjustable seed crystal pull rod, a crystal pulling device and a coaxiality adjusting method of the adjustable seed crystal pull rod and the crystal pulling device. Background The single crystal silicon material with large size and low defect rate is a basic core material of the national strategic emerging industries such as semiconductor chips, photovoltaic power generation and the like, and the Czochralski single crystal furnace is used as final equipment for producing the material, the technical performance of the material directly determines the purity, uniformity and production cost of crystals, and is a key constraint link for upgrading the industry to high-end. Currently, mainstream czochralski crystal growing equipment is generally composed of a rotary lifting module, a furnace body, a heating coil, a crucible and other core modules. The basic working principle is that after the polycrystalline silicon material is heated and melted in a crucible, the lower end of a seed crystal pull rod (or a pulling head) fixedly arranged on a rotary lifting module is used for clamping the seed crystal and making the seed crystal descend to be immersed into a melt, and then, the seed crystal is gradually grown into a large-sized monocrystalline silicon rod through the technological process of seeding, shouldering, isodiametric growth and ending by precisely controlling the pulling speed, the rotating speed and the temperature field. Finally, the semiconductor wafer is cut, ground and polished from the ingot. Therefore, the motion accuracy (especially the coaxiality and straightness of the rotation axis) of the seed crystal pull rod serving as the only mechanical tie connecting the driving system and the crystal growth interface is one of the core factors influencing the crystal quality. However, the single crystal furnace equipment in the prior art has significant bottlenecks which cannot be effectively solved for a long time in the following three key structural links, which together lead to the problems of high crystal defect rate and high equipment maintenance cost: Firstly, the dynamic sealing has poor reliability and becomes a potential source of crystal pollution, and in order to ensure the high-purity inert gas or vacuum environment required by single crystal growth, dynamic sealing is required between the rotary lifting module and the fixed furnace body. Magnetic fluid sealing or complex mechanical labyrinth sealing is commonly adopted at present, the sealing structures are exposed to high-temperature radiation (the temperature of a heat source reaches 1450 ℃) of a hearth and periodical lifting and rotating movement for a long time, performance attenuation and leakage rate increase are easy to occur, the problem leads to two serious consequences that firstly, the sealing reliability of vacuum or protective atmosphere is reduced, external air or impurity gas (such as oxygen and carbon) possibly infiltrates to damage the purity in the furnace, the impurities become sources of defects of dislocation, oxygen precipitation and the like after being captured by crystals, secondly, excessively complex heat protection and cooling structures are additionally arranged for enhancing the sealing, and the complexity and maintenance difficulty of equipment are increased, so that the operation cost is raised. Secondly, the seed crystal pull rod system lacks an effective active aligning mechanism, and concentricity deviation is amplified step by step and cannot be corrected; in order to improve the service life of the dynamic seal, the conventional equipment generally sets a rotary lifting module at a position far away from a high-temperature area, so that the length of a seed rod (a base rod) is obviously increased, an ultra-long cantilever beam structure enables any tiny initial installation error, connection gap or material deformation to be geometrically amplified at the end of a rod body and to be represented as serious radial runout, the runout can be directly transmitted to a solid-liquid interface to interfere with axisymmetric growth of crystals, crystal transformation (polycrystal) is extremely easy to induce or screw dislocation is generated, in the prior art, the seed rod is generally connected by an integral or simple flange, once the installation is finished, concentricity deviation between the end of the seed rod and the rod body cannot be directly and finely corrected on the equipment, the only correction mode is to be integrally detached, the detection and the replacement attempt are carried out on an external platform, the process is time-consuming (vacuum breaking, temperature reduction, reinstallation, re-vacuumization and the like are required), the p