Spindle supporting zone-melting single crystal growth structure

Abstract

The utility model relates to a spindle supporting zone-melting single crystal growth structure which is structurally characterized in that a supporting single crystal rod is arranged on a lifting driving mechanism, the supporting single crystal rod is obliquely arranged, the top end of the supporting single crystal rod faces a single crystal rod, a coil is arranged above the single crystal rod, the bottom end of the single crystal rod is connected with the top end of a seed crystal, the seed crystal is fixed on a seed crystal chuck, and the seed crystal chuck is mounted at the top end of a seed crystal positioning rod. The bottom end of the seed crystal positioning rod is fixed at the top end of the positioning lifting head, the bottom of the positioning lifting head is fixed at the top of the spindle, and a solution storage cup is arranged outside the middle of the seed crystal positioning rod. Compared with an inner shaft structure in the prior art, the inner shaft structure has the advantages that firstly, the manufacturing cost of the main shaft can be greatly reduced, and the purchasing cost can be reduced by more than 30%; 2, the spindle top seals the single-crystal solution, so that the interior of the spindle can be prevented from being scalded; non-metal positioning parts are not involved, and the use cost can be effectively reduced; and 4, for large-size single crystals, the success rate of shouldering can be improved to 90% from the original 60%, and the crystal forming rate is greatly improved.

Description

Technical Field

[0001] This utility model relates to a spindle-supported zone melting single crystal growth structure, belonging to the technical field of zone melting silicon single crystal furnaces. Background Technology

[0002] A float zone crystal growth furnace is a device used for float zone melting purification and float single crystal growth. It is mainly used for the purification and single crystal growth of zone-melted silicon and has been used in the industrial production of semiconductor materials.

[0003] Its mechanical structure consists of two parts: the furnace chamber and the mechanical transmission system. The furnace chamber is a stainless steel water-jacketed vertical container that can be evacuated to a high vacuum or purged with flowing argon gas. An upper shaft and a lower shaft are inserted from the top and bottom of the furnace chamber, respectively. The lower end of the upper shaft holds a polycrystalline silicon rod, and the top end of the lower shaft holds a seed crystal. A single-turn high-frequency heating coil is installed in the center of the furnace chamber. The upper and lower shafts can rotate and move up and down independently. The crystal pulling process is briefly described as follows: The upper shaft suspends the polycrystalline raw material rod. When the lower shaft approaches the heating coil, the polycrystalline rod is induction heated and melted. The polycrystalline silicon solution flows onto the seed crystal held by the lower shaft, and through processes such as necking growth, shoulder growth, constant diameter growth, and tail growth, the zone-melting single crystal is prepared. During the shoulder growth process, to more securely hold the single crystal rod, the clamping action needs to be completed before the constant diameter growth.

[0004] For existing zone melting silicon single crystal furnaces, an internal shaft crystal pulling and shoulder-forming structure is generally used. This structure has the following disadvantages: 1. It requires extremely high precision machining of the spindle's inner hole, resulting in high spindle costs; 2. Due to the structural flaws, the spindle is extremely prone to burns and scrapping during large-scale single crystal melting; 3. Since the internal shaft positioning parts can only be made of non-metallic materials such as rubber, they are easily worn and become consumable parts, resulting in high operating costs; 4. Regarding crystal pulling success rate, the internal shaft structure does not have significant disadvantages for small-sized single crystals such as 3-5 inch zone melting single crystals; however, for large-sized single crystals, the shoulder-forming success rate can only reach 60%, resulting in a consistently low overall single crystal pulling yield. Utility Model Content

[0005] This invention proposes a spindle-supported zone melting single crystal growth structure, which aims to overcome the above-mentioned shortcomings of the existing technology and eliminate the inner axis crystal pulling and shoulder formation while ensuring functionality.

[0006] The technical solution of this utility model is as follows: A spindle-supported zone melting single crystal growth structure, which includes a spindle, a supporting single crystal rod, a single crystal rod, and a seed crystal. The supporting single crystal rod is set on a lifting drive mechanism, and the supporting single crystal rod is inclined with its top end facing the single crystal rod. A coil is located above the single crystal rod, and the bottom end of the single crystal rod is connected to the top end of the seed crystal. The seed crystal is fixed on a seed crystal chuck, and the seed crystal chuck is installed on the top end of a seed crystal positioning rod. The bottom end of the seed crystal positioning rod is fixed to the top end of a positioning lifting head, and the bottom end of the positioning lifting head is fixed to the top of the spindle. A solution storage cup is provided on the outer side of the middle part of the seed crystal positioning rod. During the lead-in stage, the height of the seed crystal is higher than that of the supporting single crystal rod. As the spindle descends and the shoulder-forming process proceeds, when the diameter of the single crystal rod approaches the set value, the lifting drive mechanism drives the supporting single crystal rod to rise. When the supporting single crystal rod is about 5-10mm higher than the melting zone, it stops. As the shoulder-forming process continues, the diameter of the single crystal melting zone increases, causing the end of the supporting single crystal rod to fuse into the single crystal rod, thus providing stable support and fixation for the single crystal rod. Specifically, the supporting single crystal rises to the melting zone and melts with the melting zone, cools, and solidifies together with the single crystal.

[0007] Preferably, the lifting drive mechanism includes a screw, a lifting nut, a support rod, a lifting outer sleeve, and a supporting single-crystal rod mounting base. A screw is located at the center of the main shaft, and the lifting nut is mounted on the screw. The lower end of the support rod is fixed to the lifting nut, and the upper end of the support rod is connected to the lifting outer sleeve. The supporting single-crystal rod mounting base is mounted on the top of the lifting outer sleeve, and the lifting outer sleeve is slidably sleeved on the outside of the positioning lifting head. Rotation of the screw causes the lifting nut to rise, and the support rod, fixed to the lifting nut and connected to the lifting outer sleeve, thereby causing the supporting single-crystal rod to rise.

[0008] The advantages of this utility model are as follows: The structure is reasonably designed, and compared with the internal shaft structure in the prior art, it has the following advantages: First, it can significantly reduce the manufacturing cost of the spindle, and the procurement cost can be reduced by more than 30%; Second, the top of the spindle is sealed with single crystal solution, which can avoid scalding the inside of the spindle; Third, it does not involve non-metallic positioning parts, which can effectively reduce the cost of use; Fourth, for large-size single crystals, the success rate of shoulder formation can be increased from the original 60% to 90%, which greatly improves the crystal formation rate. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the guide stage of the spindle-supported zone melting single crystal growth structure of this utility model.

[0010] Figure 2 This is a schematic diagram of the shoulder formation process of the spindle-supported zone melting single crystal growth structure of this utility model.

[0011] In the diagram, 1 is a single crystal rod, 2 is a coil, 3 is a seed crystal, 4 is a supporting single crystal rod, 5 is a seed crystal chuck, 6 is a supporting single crystal rod mounting base, 7 is a seed crystal positioning rod, 8 is a lifting jacket, 9 is a solution storage cup, 10 is a positioning lifting head, 11 is a lifting nut, 12 is a support rod, 13 is a spindle, 14 is a screw, and D is the set diameter of the single crystal rod. Detailed Implementation

[0012] The present invention will be further described in detail below with reference to embodiments and specific implementation methods.

[0013] like Figure 1 , 2 As shown, a spindle-supported zone melting single crystal growth structure includes a spindle 13, a supporting single crystal rod 4, a single crystal rod 1, and a seed crystal 3. A screw 14 is located at the center of the spindle 13, and a lifting nut 11 is installed on the screw 14. The lower end of the supporting rod 12 is fixed to the lifting nut 11, and the upper end of the supporting rod 12 is connected to a lifting sleeve 8. A supporting single crystal rod mounting seat 6 is installed on the top of the lifting sleeve 8. The supporting single crystal rod mounting seat 6 is provided with a supporting single crystal rod 4 that is inclined and has its top facing the single crystal rod 1. A coil 2 is located above the single crystal rod 1. The bottom end of the single crystal rod 1 is connected to the top end of the seed crystal 3. The seed crystal 3 is fixed on a seed crystal chuck 5. The seed crystal chuck 5 is installed on the top end of a seed crystal positioning rod 7. The bottom end of the seed crystal positioning rod 7 is fixed to the top end of a positioning lifting head 10. The bottom end of the positioning lifting head 10 is fixed to the top of the spindle 13. The lifting sleeve 8 is slidably sleeved on the outside of the positioning lifting head 10. A solution storage cup 9 is provided on the outer side of the middle part of the seed crystal positioning rod 7.

[0014] The screw 14, lifting nut 11, support rod 12, lifting sleeve 8, and support single crystal rod mounting base 6 constitute the lifting drive mechanism for supporting single crystal rod 4.

[0015] Based on the above structure, during operation, in the lead-in stage, such as Figure 1 As shown, the height of seed crystal 3 is higher than that of supporting single crystal rod 4. Supporting single crystal rod 4 is fixed to supporting single crystal rod mounting base 6 and to lifting sleeve 8. As the spindle 13 descends and the shoulder-forming process proceeds, when the diameter of single crystal rod 1 approaches the set value D, the screw 14 rotates, causing the lifting nut 11 to rise. Support rod 12 is fixed to the lifting nut 11 and connected to lifting sleeve 8, thereby causing supporting single crystal rod 4 to rise. When supporting single crystal rod 4 is about 5-10mm higher than the melting zone, the process stops. As the shoulder-forming process continues, the diameter of the single crystal melting zone increases, causing the end of supporting single crystal rod 4 to fuse into the single crystal rod 1, thus providing stable support and fixation for the single crystal rod 1. Specifically, the supporting single crystal rises to the melting zone and melts with the melting zone, cools, and solidifies together with the single crystal. Figure 2 As shown.

[0016] All of the components described above are existing technologies, and those skilled in the art can use any model and existing design that can achieve their corresponding functions.

[0017] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present utility model, and these all fall within the protection scope of the present utility model.

Claims

1. A spindle supported zone melting single crystal growth structure, characterized by, Including main shaft (13), support single crystal rod (4), single crystal rod (1) and seed crystal (3), support single crystal rod (4) is set on the lifting drive mechanism, support single crystal rod (4) is obliquely arranged and the top end is towards single crystal rod (1), single crystal rod (1) top is coil (2), single crystal rod (1) bottom end connects seed crystal (3) top, seed crystal (3) is fixed on seed crystal chuck (5), seed crystal chuck (5) is installed on seed crystal positioning rod (7) top, seed crystal positioning rod (7) bottom end is fixed on the top of positioning lifting head (10), the bottom of positioning lifting head (10) is fixed on the top of main shaft (13), the outside of seed crystal positioning rod (7) middle part is equipped with solution storage cup (9).

2. A spindle supported zone melting single crystal growth structure as claimed in claim 1, wherein, The lifting drive mechanism includes screw rod (14), lifting nut (11), support rod (12), lifting sleeve (8) and support single crystal rod mounting seat (6), the center of main shaft (13) is equipped with screw rod (14), screw rod (14) is installed on lifting nut (11), the lower end of support rod (12) is fixed on lifting nut (11), the upper end of support rod (12) is connected with lifting sleeve (8), lifting sleeve (8) top is installed with support single crystal rod mounting seat (6), lifting sleeve (8) is slidably sleeved on the outside of positioning lifting head (10).

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