Device for measuring diameter of single crystal in special-shaped thermal field

Abstract

The utility model provides a device for measuring the diameter of a single crystal in a special-shaped thermal field, which comprises a monitoring device I, a monitoring device II and a controller, and is characterized in that the controller is used for switching the working states of the monitoring device I and the monitoring device II; the monitoring visual fields of the monitoring equipment I and the monitoring equipment II are respectively positioned on the inner side and the outer side of the water-cooled jacket so as to monitor the temperature of the silicon liquid or the diameter of the single crystal in different periods. According to the utility model, the monitoring device I and the monitoring device II of which the monitoring view field falls on the inner side and the outer side of the water cooling structure are arranged, so that the whole-process monitoring of single crystal temperature stabilization, seeding and shouldering is realized, the smooth transition of the diameter from an original shielding area to a measurable area is realized, and meanwhile, the opening at the lower edge of the water cooling structure can be avoided; and the water cooling structure has important significance for improving the production quality of the Czochralski single crystal.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor production, in particular to a device for measuring the diameter of a single crystal in a special-shaped thermal field. Background Art

[0002] In the process of producing single crystal silicon rods by the Czochralski method, the diameter of the single crystal silicon rod needs to be continuously monitored to control the pulling speed and ensure that the quality and size of the crystal rod meet the production requirements. With the continuous improvement of single crystal production technology, in order to increase the axial temperature gradient on the outside of the crystal rod and increase the pulling speed, the industry has introduced a variety of cooling measures, such as water cooling screens, water cooling jackets and other cooling structures, but the introduction of these cooling structures also brings great challenges to monitoring the diameter of single crystals.

[0003] The water-cooling screen, water-cooling jacket and other structures are set around the outside of the crystal rod, and their lower edge will block the monitoring field of view of the monitoring equipment. When the diameter of the crystal rod is small during the seeding stage and the early stage of shoulder release, the monitoring equipment cannot capture the crystal rod signal and cannot adjust the appropriate crystal pulling speed according to the diameter of the crystal rod, which often leads to quality problems such as fine grain dislocation. It is impossible to judge whether the shape trend of the crystal rod meets the production requirements and the production quality of the crystal rod cannot be guaranteed. In order to solve this problem, the traditional approach is to open a notch at the lower edge of the water-cooling screen and water-cooling jacket to make the monitoring field of view of the monitoring equipment unobstructed. However, in this way, an effective closed water-cooling cooling structure cannot be formed, and its cooling effect will be greatly reduced. Utility Model Content

[0004] The utility model aims to provide a device for measuring the diameter of a single crystal in a special-shaped thermal field, so as to solve the problems in the above background.

[0005] The technical solution adopted by the utility model is: a device for measuring the diameter of a single crystal in a special-shaped thermal field, which includes: a monitoring device 1, a monitoring device 2 and a controller, wherein the controller is used to switch the working states of the monitoring device 1 and the monitoring device 2; the monitoring fields of the monitoring device 1 and the monitoring device 2 are respectively located on the inner and outer sides of a water cooling jacket to monitor the silicon liquid temperature or the single crystal diameter at different periods.

[0006] Preferably, the water cooling jacket passes through the neck cavity of the single crystal furnace cover, and the bottom end thereof extends into the inner side of the guide tube.

[0007] Preferably, the monitoring device is installed 200mm to 300mm above the neck cavity of the single crystal furnace cover, and its monitoring field of view is located on the inner side of the water cooling jacket, and is used to monitor the silicon liquid temperature in the temperature stabilization stage, the single crystal diameter in the early stage of crystal induction and shoulder release.

[0008] Preferably, the water cooling jacket is located below the monitoring device 1, and the monitoring device 1 is provided with at least two groups, and each of the monitoring devices 1 is symmetrical about the axis of the water cooling jacket.

[0009] Preferably, the second monitoring device is installed at the neck cavity of the single crystal furnace cover, and its monitoring field of view is located outside the water cooling jacket, and is used to monitor the diameter of the single crystal in the later stage of shouldering.

[0010] Preferably, the monitoring device 1 and the monitoring device 2 are both CCD industrial cameras.

[0011] Preferably, the monitoring windows of the monitoring device 1 and the monitoring device 2 are both provided with gold-plated glass to isolate the heat source.

[0012] The beneficial effect of the utility model is that: by setting the monitoring field of the monitoring device 1 and the monitoring device 2 to fall on the inner and outer sides of the water-cooling structure, the whole process of single crystal temperature stabilization, crystal induction and shoulder release can be monitored, and a smooth transition of the diameter from the original shielding area to the measurable area can be achieved. At the same time, the problem of opening a gap at the bottom edge of the water-cooling structure, which affects the integrity of the water-cooling structure and the cooling effect, is avoided. This is of great significance to improving the production quality of direct-pull single crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a working state diagram of monitoring device 1 in an embodiment of the utility model;

[0014] Figure 2 It is a working state diagram of monitoring device 2 in the embodiment of the utility model.

[0015] In the figure:

[0016] 1. Monitoring equipment 1; 2. Monitoring equipment 2; 3. Controller; 4. Water cooling jacket; 5. Single crystal furnace cover; 6. Gold-plated glass; 7. Single crystal. DETAILED DESCRIPTION

[0017] The technical solution of the embodiment of the utility model is described in detail below with reference to the accompanying drawings.

[0018] In the description of the embodiments of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "set" and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood by specific circumstances.

[0019] Reference Figure 1-2 The present embodiment provides a device for measuring the diameter of a single crystal in a special-shaped thermal field, which is installed near a water-cooling jacket 4 on a single crystal furnace 7. The water-cooling jacket 4 penetrates the neck cavity of a single crystal furnace cover 5, and the bottom end extends into the inner side of a guide tube to ensure the cooling effect on the single crystal 7 and improve the subsequent crystal pulling speed. The lower edge of the water-cooling jacket 4 blocks the monitoring field of view, causing the monitoring equipment to be unable to capture the image of the seed crystal in contact with the silicon liquid during the temperature stabilization stage, the crystal seeding stage, and even the early stage of shoulder release, and unable to capture the diameter state of the shoulder of the single crystal 7 during the crystal seeding and shoulder release processes. The problem is solved by the monitoring equipment 1, the monitoring equipment 2, and the controller 3 in the present measuring device. The controller 3 is used to switch the working states of the monitoring equipment 1 and the monitoring equipment 2; the monitoring fields of the monitoring equipment 1 and the monitoring equipment 2 are respectively located on the inner and outer sides of the water-cooling jacket 4 to monitor the silicon liquid temperature or the single crystal diameter at different times.

[0020] The above-mentioned monitoring device 1 and monitoring device 2 2 both use CCD industrial cameras, which have monitoring recording mode and capture frame mode. The capture frame mode is used to capture the pixel value of the junction point between the edge of the single crystal 7 and the silicon liquid to obtain the single crystal diameter information.

[0021] In this embodiment, monitoring device 1 is installed at 200mm to 300mm above the neck cavity of the single crystal furnace cover 5, and its monitoring field of view is located on the inner side of the water cooling jacket 4, and is used to monitor the silicon liquid temperature in the temperature stabilization stage, the crystal induction and the single crystal diameter in the early stage of shoulder release; monitoring device 2 is installed at the neck cavity of the single crystal furnace cover 5, and its monitoring field of view is located on the outer side of the water cooling jacket 4, and is used to monitor the single crystal diameter in the later stage of shoulder release.

[0022] When monitoring the silicon liquid temperature in the temperature stabilization stage, the controller 3 controls the monitoring device 1 to be in the monitoring and recording mode. When the seed crystal approaches the high-temperature silicon liquid, the fluctuation of the silicon liquid surface recorded by the monitoring device 1 can be judged. If the silicon liquid climbs up along the edge of the crucible and faint black dots or black silk appear on the top, the temperature reaches the seeding temperature; and from the beginning of seeding to the early stage of shoulder release, the controller 3 controls the monitoring device 1 to switch to the capture frame mode. Due to the small diameter of the single crystal, the lower edge of the water-cooling jacket 4 tightly blocks the junction between the outer edge of the single crystal 7 and the silicon liquid, and the monitoring device 2 2 cannot record the state of the single crystal 7 from the outside of the water-cooling jacket 4. At this time The monitoring device 1 falls into the monitoring field of view inside the water-cooling jacket 4, and records the changes in the diameter of the single crystal in the early stage of crystal induction and shoulder release, monitors the diameter of the fine crystal and uses it to adjust the pulling speed of the single crystal 7, eliminates the generation of dislocations, and ensures that the shape trend of the single crystal 7 is correct, and monitors whether there are wire break accidents to ensure the production quality of the single crystal 7; as the diameter of the single crystal grows until the late stage of shoulder release, the junction point between the outer edge of the single crystal 7 and the silicon liquid is exposed in the monitoring field of the monitoring device 2 2, and the controller 3 controls the monitoring device 1 to switch to the monitoring recording mode, and controls the monitoring device 2 to switch to the capture frame mode to measure the diameter of the single crystal in the late stage of shoulder release.

[0023] Since the monitoring field of the monitoring device 1 is located inside the water-cooling jacket 4 and its monitoring field of view is blocked by the single crystal 7, it can only capture the signal on one side of the single crystal 7 at most. Therefore, in this embodiment, the water-cooling jacket 4 is located below the monitoring device 1, and at least two groups of monitoring devices 1 are provided. Each monitoring device 1 is symmetrical about the axis of the water-cooling jacket 4 to form a complete and blind-angle-free monitoring of the single crystal 7 in the circumferential direction, thereby improving the accuracy of the single crystal diameter measurement.

[0024] Since the temperature inside the single crystal furnace 7 is relatively high, in order to protect the structural safety of the monitoring device 1 1 and the monitoring device 2 2 and to increase their service life, in this embodiment, gold-plated glass 6 is provided at the monitoring windows of the monitoring device 1 1 and the monitoring device 2 2 to isolate the heat source.

[0025] Compared with the prior art, the beneficial effect of the utility model lies in that: by setting the monitoring field of the monitoring device 1 and the monitoring device 2 2 to fall on the inner and outer sides of the water-cooling structure, the whole process of temperature stabilization, crystal induction and shoulder release of the single crystal 7 can be monitored, and a smooth transition of the diameter from the original shielding area to the measurable area can be achieved. At the same time, it can also avoid the problem of opening a gap at the bottom edge of the water-cooling structure, which affects the integrity of the water-cooling structure and the cooling effect. This is of great significance to improving the production quality of the direct-pull single crystal 7.

[0026] The above are preferred implementations of the present utility model. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present utility model. These improvements and modifications should also be regarded as the protection scope of the present utility model.

Claims

1. A device for measuring the diameter of a single crystal in a special-shaped thermal field, characterized in that: include: Monitoring device 1, monitoring device 2 and a controller, wherein the controller is used to switch the working states of the monitoring device 1 and the monitoring device 2; The monitoring fields of the monitoring device 1 and the monitoring device 2 are respectively located on the inner and outer sides of the water cooling jacket to monitor the silicon liquid temperature or the single crystal diameter at different periods.

2. The device for measuring the diameter of a single crystal in a special-shaped thermal field according to claim 1, characterized in that: The water cooling jacket passes through the neck cavity of the single crystal furnace cover, and the bottom end thereof extends into the inner side of the guide tube.

3. The device for measuring the diameter of a single crystal in a special-shaped thermal field according to claim 2, characterized in that: The monitoring device is installed 200mm to 300mm above the neck cavity of the single crystal furnace cover, and its monitoring field of view is located on the inner side of the water cooling jacket, and is used to monitor the silicon liquid temperature in the temperature stabilization stage, the single crystal diameter in the early stage of seeding and shouldering.

4. The device for measuring the diameter of a single crystal in a special-shaped thermal field according to claim 3, characterized in that: The water cooling jacket is located below the monitoring device 1. The monitoring device 1 is provided with at least two groups, and each of the monitoring devices 1 is symmetrical about the axis of the water cooling jacket.

5. The device for measuring the diameter of a single crystal in a special-shaped thermal field according to claim 1, characterized in that: The second monitoring device is installed at the neck cavity of the single crystal furnace cover, and its monitoring field of view is located outside the water cooling jacket, and is used to monitor the diameter of the single crystal in the later stage of shouldering.

6. A device for measuring the diameter of a single crystal in a special-shaped thermal field according to any one of claims 1 to 5, characterized in that: The monitoring device 1 and the monitoring device 2 are both CCD industrial cameras.

7. The device for measuring the diameter of a single crystal in a special-shaped thermal field according to claim 6, characterized in that: The monitoring windows of the monitoring device 1 and the monitoring device 2 are both provided with gold-plated glass to isolate the heat source.

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