KR102681152B1 - The melt gap maintaining apparatus for manufacturing single crystal ingot and melt gap maintaining method using the same - Google Patents

Abstract

A weighing module that measures the change in weight of a crucible containing a silicon melt; a camera module installed outside the transparent window provided in the chamber accommodating the crucible and measuring a change in height of the surface of the silicon melt; And a control unit that rotates and rises at a predetermined speed according to the change in the weight of the crucible, corrects the rising position of the crucible based on the height of the surface of the silicon melt measured simultaneously with the rotational rise of the crucible, and maintains a predetermined melt gap; Provided is a melt gap maintaining device for manufacturing a single crystal ingot and a melt gap maintaining method using the same.

Description

Melt gap maintaining apparatus for manufacturing single crystal ingot and melt gap maintaining method using the same {The melt gap maintaining apparatus for manufacturing single crystal ingot and melt gap maintaining method using the same}

The present invention is a melt gap maintenance device for manufacturing a single crystal ingot that can simultaneously recognize the weight change profile and the height change of the silicon melt surface during the single crystal ingot growth process to correct the position of the crucible and keep the melt gap constant during the process, and a melt gap maintenance device using the same. This is about how to maintain the melt gap.

Methods for growing silicon single crystal ingots include the floating zone (FZ) method or the Czochralski (CZ) method, and the currently common method is the CZ method. The CZ method is a method of growing a single crystal silicon ingot by charging polycrystalline silicon into a crucible, heating and melting it, then immersing the seed in the silicon melt and rotating and pulling the seed when crystallization occurs at the interface. At this time, the crucible is raised while rotating the axis supporting the crucible so that the solid-liquid interface is maintained at the same height, and with the same axis as the rotation axis of the crucible as the central axis, the silicon single crystal ingot is pulled up while rotating in the opposite direction to the rotation direction of the crucible. Make it grow.

To ensure the quality and productivity of single crystal ingots, the CZ method's manufacturing equipment includes a heat shielding member (reflector) that blocks heat radiated from the surface of the silicon melt and the heating member from being transferred to the silicon single crystal ingot, and maintains a constant melt gap. Maintain or variable control. For example, the surface height of the silicon melt is controlled by the difference value generated by calculating the volume ratio of the volume of the single crystal ingot and the volume ratio of the crucible containing the melt, and if the surface height of the melt changes due to the growth of the single crystal ingot, the operator manually manipulates it. This correction method keeps the surface height of the silicon melt constant. That is, in the control based on the above calculation, errors may occur between the actual value and the calculated value due to causes such as deformation of the crucible during the process, as shown in FIG. 1. Therefore, it may depend on manual work done by the worker's eyes, which may result in low productivity due to difficulty in controlling a certain level of precision depending on the worker's skill level, and may cause process accidents.

To solve this problem, Korean Patent Publication No. 10-2014-0097834, 'Single Crystal Ingot Growth Device', is attached to the bottom of the heat shield and captures the image of the reflection of the measuring rod placed on the melt through the viewport of the chamber. A technology for measuring the melt gap using a device has been disclosed. However, the rotation of the crucible and ingot may distort the reflected image, which may reduce the accuracy of the melt gap measurement.

Korean Patent Publication No. 10-2014-0097834 (Publication date: August 7, 2014) Korean Patent No. 10-1841550 (registration date: March 19, 2018) Korean Patent No. 10-1443494 (registration date: September 16, 2014)

The technical problem to be achieved by the present invention is to simultaneously recognize the change in the weight of the crucible and the change in height of the surface of the silicon melt, so that the position of the crucible can be easily corrected regardless of the operator's skill level, and the melt gap can be kept constant during the process. The purpose is to provide a melt gap maintenance device for manufacturing a single crystal ingot and a melt gap maintenance method using the same.

The purpose of the present invention is not limited to the purposes mentioned above, and other purposes not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the above problem, the present invention includes a weight measurement module that measures the change in weight of a crucible containing a silicon melt; a camera module installed outside the transparent window provided in the chamber accommodating the crucible and measuring a change in height of the surface of the silicon melt; And a control unit that rotates and rises at a predetermined speed according to the change in the weight of the crucible, corrects the rising position of the crucible based on the height of the surface of the silicon melt measured simultaneously with the rotational rise of the crucible, and maintains a predetermined melt gap; It is possible to provide a melt gap maintenance device for manufacturing a single crystal ingot, comprising:

The camera module may include a pair of infrared stereo cameras that measure changes in height of the surface of the silicon melt using triangulation.

The weight measurement module may include a load cell located below the crucible.

The melt gap maintenance device for manufacturing a single crystal ingot may be controlled so that the crystal growth rate is -0.2 to 0.2 mm/min during the tail process.

The single crystal ingot may have a diameter of 200 to 450 mm.

In addition, in order to solve the above problem, the present invention includes a step (a) in which a weight measurement module measures a change in the weight of a crucible containing a silicon melt; Step (b) in which a camera module installed outside the transparent window provided in the chamber measures the change in height of the silicon melt interface; And according to the change in the weight of the crucible, the crucible rotates and rises at a predetermined speed, and the control unit corrects the rising position of the crucible from the height of the silicon melt surface measured simultaneously with the rotational rise of the crucible and maintains a predetermined melt gap ( It is possible to provide a melt gap maintenance method for manufacturing a single crystal ingot, including step c), wherein steps (a) and (b) are performed simultaneously.

In step (b), the camera module may include a pair of infrared stereo cameras and measure the height change of the silicon melt interface using a triangulation method.

The melt gap maintenance method for producing a single crystal ingot may be to control the growth rate to be -0.2 to 0.2 mm/min in the tail process step.

The single crystal ingot may have a diameter of 200 to 450 mm.

The melt gap maintenance device for manufacturing a single crystal ingot and the melt gap maintenance method using the same according to an embodiment of the present invention are equipped with a weight measurement module and a camera module to simultaneously recognize the amount of change in the weight of the crucible and the change in height of the silicon melt surface to determine the operator's skill level. Regardless, the position of the crucible can be easily corrected and the melt gap can be kept constant during the process.

1 is a graph showing calculated and actual values for the crucible rising speed;
Figure 2 is a block diagram showing a melt gap maintenance device for manufacturing a single crystal ingot according to an embodiment of the present invention;
Figure 3 is a cross-sectional view showing a melt gap maintenance device for manufacturing a single crystal ingot according to an embodiment of the present invention;
Figure 4 is a simplified diagram showing the triangulation and melt gap correction of the camera module of the melt gap maintenance device for manufacturing a single crystal ingot according to an embodiment of the present invention;
Figure 5 is a photograph and cross-sectional view showing the slip phenomenon of a single crystal during the tail process;
Figure 6 is a graph showing comparison of tail weight measured according to single crystal diameter;
Figure 7 is a graph showing a comparison of growth rate and tail loss during the tail process.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments introduced below are provided as examples so that the idea of the present invention can be sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. Also, in the drawings, the length and thickness of layers and regions may be exaggerated for convenience. Like reference numerals refer to like elements throughout the specification.

Figure 1 is a graph showing calculated values and actual values for the crucible rising speed, Figure 2 is a block diagram showing a melt gap maintenance device for manufacturing a single crystal ingot according to an embodiment of the present invention, and Figure 3 is an embodiment of the present invention. It is a cross-sectional view showing a melt gap holding device for producing a single crystal ingot according to an embodiment of the present invention, and Figure 4 is a simplified view showing the triangulation and melt gap correction of the camera module of the melt gap holding device for producing a single crystal ingot according to an embodiment of the present invention, and Figure 5 is a tail A photograph and cross-sectional view showing the slip phenomenon of a single crystal during the process, Figure 6 is a graph showing a comparison of tail weight measured according to the single crystal diameter, and Figure 7 is a graph showing a comparison of the growth rate and tail loss during the tail process.

Referring to FIGS. 2 to 7, the melt gap maintaining device 10 for manufacturing a single crystal ingot according to an embodiment of the present invention includes a weight measurement module 100 that measures the change in weight of the crucible 20 containing the silicon melt (M). ); A camera module 200 installed outside the transparent window 44 provided in the chamber 40 for accommodating the crucible 20 and measuring the change in height of the silicon melt surface S; And according to the change in the weight of the crucible 20, the crucible 20 rotates and rises at a predetermined speed, and the height of the silicon melt surface S measured simultaneously with the rotational rise of the crucible 20 increases. It may include a control unit 300 that corrects the rising position and maintains a predetermined melt gap. Therefore, the melt gap maintenance device 10 for manufacturing a single crystal ingot is equipped with a weight measurement module 100 and a camera module 200 to simultaneously recognize the amount of change in the weight of the crucible 20 and the change in height of the silicon melt surface (S) to allow the operator The position of the crucible 20 can be easily corrected regardless of the skill level, and there is an advantage in that the melt gap can be kept constant during the process.

In detail, the crucible 20 may include a susceptor in which the rotation axis 60 is coupled to the center of the lower portion and an internal crucible coupled to the inside of the susceptor. Polycrystalline silicon and dopants such as antimony, boron, and phosphorus may be charged together into the crucible 20 and melted. Heat for the melting may be supplied by a heating means (not shown) located around the crucible 20.

A single crystal seed is located at one end of the seed wire 30. In a state where a single crystal seed is immersed in a silicon melt (M) in which polycrystalline silicon is melted, a pulling means (not shown) can move and rotate the growing silicon single crystal. That is, the pulling means pulls up the seed wire 30, and the silicon melt M can be manufactured into a single crystal ingot I having a predetermined diameter due to the single crystal seed. Manufacturing a silicon single crystal ingot (I) consists of a process of charging material, melting the material, and raising the seed. The pulling of the seed is done by contacting the seed with the silicon melt (M) and then moving the crucible 20 and the seed in opposite directions. The seed is slowly raised while rotating, which allows a silicon single crystal ingot (I) to be grown. For example, the silicon single crystal ingot (I) may have a specific resistance of 0.01Ωcm or less and a diameter of 200 to 450 mm.

The heat shielding means (50), which maintains a certain gap with the silicon melt (M) and is located on top of the silicon melt (M), is disposed around the single crystal ingot (I) when it grows and acts as an insulator, and the ingot (I) It can have a hollow shape with both sides open, which affects the pulling speed or the quality of the grown ingot. In general, the heat shield means 50 may be formed so that the diameter of the upper opening is larger than the diameter of the lower opening.

An inert gas may be introduced into the chamber 40 that accommodates the crucible 20, seed wire 30, and heat shield 50. That is, the inert gas supplied into the chamber 40 maintains a constant pressure within the chamber 40 and removes gaseous impurities such as antimony oxide or oxygen that may be generated during the production of the silicon single crystal ingot (I) from the chamber 40. It can be discharged to the outside.

The weight measurement module 100 that measures the change in weight of the crucible 20 containing the silicon melt M may include a load cell located at the lower part of the crucible 20. In other words, the weight of the grown ingot (I) may correspond to the weight obtained by subtracting the remaining amount of silicon melt from the initial silicon melt (M), which can be derived from the crucible weight measurement value of the load cell located at the bottom of the crucible (20). You can. And since the silicon melt decreases depending on the growing ingot, the crucible can rotate at a predetermined speed and increase in height to maintain the melt gap.

The camera module 200, which is installed outside the transparent window 44 provided in the chamber 40 for accommodating the crucible 20 and measures (detects) the change in height of the silicon melt surface S, is shown in FIG. 4 and Likewise, it may include a pair of infrared stereo cameras 201 and 202 that measure the change in height of the silicon melt surface (S) using a triangulation method. A pair of infrared stereo cameras 201 and 202 may be set to focus on the initial silicon melt surface S where ingot growth begins. That is, the pair of infrared stereo cameras 201 and 202 may be focused on the silicon melt surface S at the time the melt gap is determined.

According to the change in the weight of the crucible 20, the crucible 20 rotates and rises at a calculated and preset speed, and the control unit 300 controls the surface (S) of the silicon melt measured simultaneously with the rotational rise of the crucible 20. It is possible to correct the rising position of the crucible 20 from the height and maintain a predetermined melt gap.

The thickness of the crucible varies for each product, and thermal deformation due to thickness differences may appear differently for each crucible. Therefore, when the crucible 20 for the single crystal ingot manufacturing process is raised, a difference may occur between the actual crucible position and the crucible position moved according to the preset value due to deformation of the crucible.

If the position of the crucible according to the preset calculated value is the same as the actual crucible position, the focus of the pair of infrared stereo cameras 201 and 202 on the silicon melt surface S can be maintained. However, when ΔH1 occurs, that is, when the actual crucible rises higher than the calculated position and the melt gap decreases from normal, the melt gap can be corrected by lowering the crucible by ΔH1. In addition, when the actual crucible is raised lower than the calculated position and the melt gap increases than normal, that is, when ΔH2 occurs, the melt gap can be corrected by raising the crucible by ΔH2. Therefore, more accurate melt gap correction and maintenance can be achieved by using the triangulation method of the pair of infrared stereo cameras 201 and 202 rather than the operator's naked eyes.

Figure 6 is a graph showing a comparison of the tail weight measured according to the single crystal diameter, and Table 1 is a table summarizing the number of times the seed wire 30 is used and the load cell location when growing ingots A to E, respectively. Referring to Figure 6 and Table 1, in the case of E and F, which can be considered embodiments of the present invention, the ingot is grown by correcting the degree of elevation of the crucible using the triangulation method of a pair of infrared stereo cameras 201 and 202. As a result, the actual measured and calculated values of the tail weight are closer to each other than other examples. That is, when the weight measurement module 100 is placed at the bottom of the crucible, the crucible position is corrected with the camera module 200, and the ingot is grown (E, F), the size of the tail according to the single crystal diameter is the actual grown size and the calculated It shows that the sizes are almost identical. This can be said to show the accuracy of melt gap maintenance.

Seed wire usage frequency Load cell location Camera module measurement presence or absence A 15 means of raising ○ B 20 means of raising ○ C 15 means of raising × D 20 means of raising × E 15 Bottom of crucible ○ F 20 Bottom of crucible ○

Furthermore, the melt gap maintenance device 10 for manufacturing a single crystal ingot may be controlled so that the crystal growth rate during the tail process is -0.2 to 0.2 mm/min. As the length of the single crystal ingot (I) increases, the resistance distribution may decrease, which can be said to be due to the rate at which impurities remaining in the melt can enter the inside of the ingot (segregation coefficient). The concentration of impurities may increase during the latter part of the body process, especially the tail process, and this may cause tail loss. As shown in Figure 5, when tail loss occurs, a slip of approximately 1.2 or more diameters occurs at the location where the tail loss occurs, which can reduce yield. Therefore, the tail process crystal growth rate is controlled to -0.2 to 0.2 mm/min to reduce tail loss. can do. Referring to Figure 7, which is a graph showing a comparison of the growth rate and tail loss during the tail process, the growth length of the ingots a to d are all 1200 mm and the diameter is 365 mm, and the tail loss of the grown ingots is compared. The comparison table of a to d is shown in Table 2 below. As shown in Figure 7 and Table 2, the weight measurement module 100 is placed at the bottom of the crucible, the crucible position is corrected with the camera module 200, and the ingot is grown, but the crystal growth rate during the tail process is -0.2 to 0.2 mm/min. (d) It can be seen that tail loss does not occur even if a low-resistance ingot is grown.

resistance level Load cell location Tail Loss a low resistance means of raising ○ b low resistance means of raising ○ c General resistance means of raising × d low resistance Bottom of crucible ×

In addition, the melt gap maintenance method for manufacturing a single crystal ingot according to an embodiment of the present invention includes the step (a) of the weight measurement module 100 measuring the change in weight of the crucible 20 containing the silicon melt (M); Step (b) in which the camera module 200 installed outside the transparent window 44 provided in the chamber 40 measures the change in height of the silicon melt interface (S); And according to the change in the weight of the crucible 20, the crucible 20 rotates and rises at a predetermined speed, and the control unit 300 determines the height of the silicon melt surface S measured simultaneously with the rotational rise of the crucible 20. It includes step (c) of correcting the rising position of the crucible 20 and maintaining a predetermined melt gap, and steps (a) and (b) may be performed simultaneously.

To explain in detail, first, polycrystalline silicon and dopants such as antimony, boron, and phosphorus are charged together into the crucible 20, and can be melted by a heating means around the crucible 20. During the manufacturing process of the silicon single crystal ingot (I), inert gas may be introduced into the chamber 40. The inert gas supplied into the chamber 40 maintains a constant pressure within the chamber 40 and removes gaseous impurities such as antimony oxide or oxygen that may be generated during the production of the silicon single crystal ingot (I) to the outside of the chamber 40. It can be discharged.

When the polycrystalline silicon is melted to produce the silicon melt (M), the seed wire 30, where the single crystal seed is located at one end, may be lowered toward the silicon melt (M) by a pulling means. While the single crystal seed is immersed in the silicon melt (M), the pulling means (not shown) can move and rotate the growing silicon single crystal. The seed can be pulled up gradually by contacting the seed with the silicon melt (M) and then rotating the crucible 20 and the seed in opposite directions, thereby growing a silicon single crystal ingot (I). . For example, the silicon single crystal ingot (I) may have a specific resistance of 0.01Ωcm or less and a diameter of 200 to 450 mm.

Throughout the seed pulling and ingot growth process, the weight measurement module 100 can measure the change in weight of the crucible 20 containing the silicon melt M (step (a)). Additionally, the camera module 200 installed outside the transparent window 44 provided in the chamber 40 can measure the change in height of the silicon melt interface S (step (b)). In this case, steps (a) and (b) may be performed simultaneously.

The weight of the growing ingot (I) may correspond to the weight obtained by subtracting the remaining amount of silicon melt from the initial silicon melt (M), which is derived from the weight measurement value of the crucible (20) of the load cell located at the bottom of the crucible (20). It can be. And since the silicon melt (M) decreases depending on the growing ingot, the crucible can rotate at a predetermined speed and increase in height to maintain the melt gap. Furthermore, in step (b), the camera module 200 includes a pair of infrared stereo cameras 201 and 202, and changes in height of the silicon melt interface S using the triangulation method as described above. It could be measuring.

Next, according to the change in weight of the crucible 20, the crucible 20 rotates and rises at a calculated, preset speed, and the control unit 300 controls the surface of the silicon melt measured simultaneously with the rotational rise of the crucible 20. A predetermined melt gap can be maintained by correcting the rising position of the crucible 20 from the height of (S) (step (c)).

The thickness of the crucible 20 varies depending on the product, and thermal deformation due to the difference in thickness may vary from crucible to crucible. Therefore, when the crucible 20 for the single crystal ingot manufacturing process is raised, a difference may occur between the actual crucible position and the crucible position moved according to the preset value.

If the position of the crucible according to the preset calculated value is the same as the actual crucible position, the focus of the pair of infrared stereo cameras 201 and 202 on the silicon melt surface S can be maintained. However, when ΔH1 occurs, that is, when the actual crucible rises higher than the calculated position and the melt gap decreases from normal, the melt gap can be corrected by lowering the crucible by ΔH1. In addition, when the actual crucible is raised lower than the calculated position and the melt gap increases than normal, that is, when ΔH2 occurs, the melt gap can be corrected by raising the crucible by ΔH2. Therefore, more accurate melt gap correction and maintenance can be achieved by using the triangulation method of the pair of infrared stereo cameras 201 and 202 rather than the operator's naked eyes.

Additionally, the method of maintaining the melt gap for producing a single crystal ingot may be to control the growth rate to be -0.2 to 0.2 mm/min in the tail process step. As explained in FIG. 7 and Table 2 above, the weight measurement module 100 is placed at the bottom of the crucible, the crucible position is corrected with the camera module 200, and the ingot is grown, but the crystal growth rate during the tail process is -0.2 to -0.2. When controlled to 0.2mm/min (d), it can be seen that tail loss does not occur even when growing an ingot with low resistance.

The melt gap maintenance device 10 for manufacturing a single crystal ingot according to an embodiment of the present invention and the melt gap maintenance method using the same include a weight measurement module 100 and a camera module 200 to measure the amount of change in weight of the crucible 20 and the silicon melt. By simultaneously recognizing the change in height of the surface S, the position of the crucible 20 can be easily corrected regardless of the operator's skill level, and there is an advantage in that the melt gap can be kept constant during the process.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can do it.

10; Melt gap maintenance device for single crystal ingot manufacturing
20; Crucible
30; seed wire
40; chamber
44; transparent window
50; Heat shielding means
100; Weighing module
200; camera module
300; control unit
I; Silicon single crystal ingot
M; silicone melt
S; Silicone melt surface

Claims (9)

A weighing module that measures the change in weight of a crucible containing a silicon melt;
a camera module installed outside the transparent window provided in the chamber accommodating the crucible and measuring a change in height of the surface of the silicon melt; and
According to the change in the weight of the crucible, the crucible rotates and rises at a predetermined speed, and a control unit that corrects the rising position of the crucible from the height of the silicon melt surface measured simultaneously with the rotational rise of the crucible and maintains a predetermined melt gap; do,
A melt gap maintenance device for manufacturing a single crystal ingot, characterized in that the crystal growth rate during the tail process is controlled to be -0.2 to 0.2 mm/min. According to paragraph 1,
The camera module is a melt gap maintenance device for manufacturing a single crystal ingot, characterized in that it includes a pair of infrared stereo cameras that measure the height change of the surface of the silicon melt by triangulation. According to paragraph 1,
The weight measurement module is a melt gap maintenance device for manufacturing a single crystal ingot, characterized in that it includes a load cell located at the bottom of the crucible. delete According to paragraph 1,
The single crystal ingot is a melt gap maintenance device for manufacturing a single crystal ingot, characterized in that it has a diameter of 200 to 450 mm. Step (a) in which the weight measurement module measures the change in weight of the crucible containing the silicon melt;
Step (b) in which a camera module installed outside the transparent window provided in the chamber measures the change in height of the silicon melt interface; and
Depending on the change in weight of the crucible, the crucible rotates and rises at a predetermined speed, and from the height of the silicon melt surface measured simultaneously with the rotational rise of the crucible, the control unit corrects the rising position of the crucible and maintains a predetermined melt gap (c) ) step;
Steps (a) and (b) are performed simultaneously,
A melt gap maintenance method for manufacturing a single crystal ingot, characterized in that the growth rate is controlled to be -0.2 to 0.2 mm/min in the tail process step. According to clause 6,
In step (b), the camera module includes a pair of infrared stereo cameras, and measures the height change of the silicon melt interface using a triangulation method. delete According to clause 6,
A melt gap maintenance method for manufacturing a single crystal ingot, characterized in that the single crystal ingot has a diameter of 200 to 450 mm.