TWI460319B - Crystal growth device and ingot manufacturing method - Google Patents

Description

Crystal growth device and crystal manufacturing method

The invention relates to a crystal growth device and a crystal production method, and particularly relates to a crystal growth device and a crystal production method capable of adjusting the temperature distribution of a molten steel surface in a crucible.

In order to manufacture a sapphire wafer, it is typical to heat the crystal growth apparatus to a high purity alumina raw material to or above 2100 degrees Celsius to melt the material, followed by a series of processes such as drilling, round grinding, slicing, and grinding. , heat treatment, and polishing to obtain a single crystal wafer.

In the manufacture of sapphire single crystals, controlling bubbles and controlling misalignment have a major impact on quality. The misalignment can be measured by an etching method after the crystal is grown. The misalignment is mainly caused by thermal stress, and the thermal stress is mainly the temperature difference between the inside and the outside of the crystal which occurs in the growth of the crystal. Therefore, the dislocation density can be controlled by controlling the thermal stress.

For example, in past experience, since the crystal growth apparatus is usually heated at its sides and bottom, it has a temperature gradient between the top and bottom of the crystal. The thermal stress generated by the above temperature gradient eventually leads to misalignment and affects the crystal quality.

Therefore, the present inventors have felt that the above-mentioned deficiencies can be improved, and they have devoted themselves to research and cooperated with the application of the theory, and finally proposed a present invention which is reasonable in design and effective in improving the above-mentioned defects.

The embodiment of the invention provides a crystal growth device and a crystal manufacturing method, which can effectively adjust the temperature distribution of the molten steel surface.

The embodiment of the invention provides a crystal growth device, comprising: a crucible; The crucible lid defines an opening, the crucible lid is mounted on the crucible, and the crucible is surrounded by the crucible lid to define an accommodating space, and the accommodating space communicates with the outside through the opening; An insulating unit disposed on an outer surface of the crucible lid; and a plurality of heat reflecting rings disposed in the receiving space and suspended from the crucible lid respectively, and any two adjacent heat reflections The rings are spaced apart, and a first angle is formed between the heat reflecting rings and the crucible cover, and the first angle is a flat angle, and the heat reflecting rings can be deformed during heating of the crystal growth device. The first angle between each heat reflecting ring and the crucible lid can be varied to a second angle, and the second angle is an acute angle.

The embodiment of the present invention further provides a crystal manufacturing method, the method comprising: providing the crystal growth device as described above; loading a raw material in the crucible; suspending the heat reflection rings under the crucible cover, and The heat insulating unit is mounted on the crucible lid, and then the crucible lid is mounted on the crucible, the heat reflecting rings are located in the receiving space; and the heating of the crystal growth device is performed to The raw material is melted to form a molten soup. During the heating of the crystal growth device, the heat reflecting rings are deformed by heat, so that the first angle between each heat reflecting ring and the crucible cap is gradually changed. The second angle to an acute angle, thereby adjusting the vertical temperature distribution and the horizontal temperature distribution of the molten stone surface.

In summary, the crystal growth device and the crystal manufacturing method provided by the embodiments of the present invention can improve the adjustable interval of the process parameters, thereby controlling the distribution of the temperature gradient on the molten steel surface, thereby reducing the probability of rapid growth of the shoulder expansion and reducing the probability. The thermal stress of the crystal is concentrated to enhance the crystal quality.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims Scope Any restrictions.

The invention is a crystal growth device and a crystal production method. First, a brief description will be given of a crystal growth apparatus used in a crystal manufacturing method, and thereafter, a crystal production method will be described.

Referring to FIG. 1A and FIG. 1B , which is an embodiment of the present invention, the present embodiment provides a crystal growth apparatus 100 including: a crucible, a crucible cover 2, a thermal insulation unit 3, and a plurality of The heat reflecting ring 4 and a hanging unit 5. Among them, the above-mentioned crucible 1 is an appliance commonly used in the industry, and therefore will not be described in detail herein.

A substantially central portion of the crucible lid 2 defines an opening 21, and a plurality of through holes 22 are formed in the portion of the crucible lid 2 adjacent to the opening 21. The crucible lid 2 is mounted on the crucible 1 so that the crucible 1 and the crucible lid 2 define an accommodating space 11 , and the accommodating space 11 can communicate with the outside through the opening 21 .

The heat insulating unit 3 has a plurality of layers of annular heat insulating sheets 31, and the heat insulating sheets 31 are sequentially stacked on the outer surface of the crucible lid 2, and the inner diameters of the heat insulating sheets 31 are larger than The opening 21 of the crucible lid 2. The above-mentioned heat insulating sheets 31 are exemplified by being in contact with each other in the drawing, but it is not excluded that the heat insulating sheets 31 are stacked and arranged at intervals. Moreover, the inner diameters of the heat insulating sheets 31 are gradually increased from the adjacent crucible lid 2 in a direction away from the crucible lid 2, that is, the opening 21 of the crucible lid 2 is not blocked by the heat insulating unit 3. Shaded. And the outer edges of the heat insulating sheets 31 are substantially aligned with the outer edges of the crucible lid 2.

Thereby, the crystal growth apparatus 100 is disposed through the heat insulation unit 3 so that the heat energy in the crucible 1 is blocked by the crucible cover 2 and the heat insulation unit 3, and is less likely to be dissipated outside, thereby increasing the heat retention effect. Furthermore, the crucible The temperature gradient outside the cover 2 is gradually affected by the thermal insulation unit 3 to gradually decrease gradually, so as to facilitate the subsequent related seeding step.

The heat reflecting ring 4 is substantially plate-shaped and is made of a material that is heat-resistant and has a certain ductility such as tantalum, tungsten, or molybdenum. In addition, for convenience of description, the heat-reflecting ring 4 shown in FIG. 1A is used as the following description, but in practical applications, the heat-reflecting ring 4 can also be adjusted to other aspects according to the designer's needs. .

For example, as shown in FIG. 1C and FIG. 1D, the heat reflecting ring 4 can be formed with an extending portion 43 at its inner edge or outer edge to change the thickness of the heat reflecting ring 4, and is suitable for subsequent adjustment of the melting. The temperature ladder distribution on the surface of the soup. Alternatively, the heat reflecting ring 4 can also be formed in a tubular configuration (not shown).

Referring to FIG. 1A and FIG. 1B , the heat reflecting ring 4 is suspended from the crucible cover 2 and disposed in the accommodating space 11 , and any two adjacent heat reflecting rings 4 are equally spaced to pass through. The distance between the two heat reflecting rings 4 reaches the effect of heat insulation. A first angle is formed between the heat reflecting ring 4 and the crucible lid 2, wherein the first angle is exemplified by a flat angle (180 degrees) in the embodiment.

In more detail, during the heating of the crystal growth apparatus 100, the heat reflection rings 4 can be deformed by their own structural design so that the first angle between each heat reflection ring 4 and the crucible cover 2 ( Figure 1A) can be varied to a second angle (Figure 2A). Wherein, the second angle is preferably an acute angle (less than 90 degrees). In addition to the second angle shown in FIG. 2A, the heat reflecting ring 4 can also be formed through different structural designs as shown in FIG. 2B. In other words, the actual state can be selected according to the designer's needs.

It should be noted that the second angle shown in FIG. 2A is a preferred embodiment. That is, when the heat reflecting ring 4 and the crucible lid 2 respectively form a second angle, the inner diameter of each heat reflecting ring 4 gradually increases from the adjacent crucible lid 2 away from the crucible lid 2 . Thereby, the condensate 201 condensed on the surface of the heat reflecting ring 4 will slide down to the outer portion along the surface of the heat reflecting ring 4 (that is, as shown in Fig. 3, the condensate 201 is drained to the side of the side wall of the crucible 1), thereby avoiding condensation. The problem of impurity dripping occurs.

Regarding the structural design of the heat reflecting ring 4 to cause deformation when the crystal growth apparatus 100 is heated, two embodiments will be described below, but it is not limited thereto.

In a first embodiment, each of the heat reflecting rings 4 has a first surface 41 and a second surface 42 opposite to each other. The thickness of the heat reflecting ring 4 is transmitted through the thickness of the heat reflecting ring 4 to transfer heat energy from the first surface 41 to the second surface 42. The first face 41 and the second face 42 produce different thermal expansion effects. Specifically, during the heating of the crystal growth apparatus 100, the first surface 41 and the second surface 42 of each heat reflection ring 4 are subjected to different thermal stresses to generate different thermal expansions. For example, the degree of thermal expansion of the second surface 42 is greater than the degree of thermal expansion of the first surface 41 such that the first angle between each of the heat reflecting rings 4 and the crucible lid 2 can be varied to a second angle.

The second embodiment: the surface (the first surface 41 or the second surface 42) of each of the heat reflecting rings 4 is formed with at least one notch (not shown). Further, during the heating of the crystal growth device 100, each heat reflection ring 4 generates a stress concentration through the portion of the heat distortion ring 4, so that the first angle between each heat reflection ring 4 and the crucible cover 2 can be changed to The second angle.

Regarding the manner in which the heat reflecting ring 4 is suspended from the crucible lid 2, a hanging unit 5 will be described below, but is not limited thereto. The hanging unit 5 includes a plurality of rod-shaped fixing members 51 (such as screws) and a plurality of positioning members 52 (such as nuts) that are matched with the fixing members 51. Furthermore, each heat reflecting ring has a shape of 4 There are a plurality of through holes 44 each having a size smaller than that of each of the positioning members 52, and the number of the through holes 44 of each of the heat reflecting rings 4 is equal to the number of the fixing members 51.

The fixing member 51 is disposed (eg, is worn) in the through hole 22 of the crucible cover 2, and the fixing member 51 passes through the through hole 44 of the heat reflecting ring 4 through the portion of the crucible cover 2 in sequence. . When the fixing member 51 passes through the through hole 44 of the heat reflecting ring 4, the positioning member 52 is installed (eg, screwed) on the fixing member 51, thereby achieving the effect of blocking the heat reflecting ring 4, that is, the heat. The reflection ring 4 will be positioned on the fixing members 51 through the positioning member 52 and then suspended from the crucible cover 2 .

There is a clearance between each of the heat reflecting rings 4 and each of the fixing members 51 to allow an angle change between the heat reflecting rings 4 and the crucible cover 2. In other words, the clearance can provide the space required for the heat reflecting ring 4 to deform, so as to prevent the heat reflecting ring 4 from being damaged by the deformation of the fixing member 51 due to the deformation.

The crystal growth apparatus 100 has been described above, and the following description will be made on how to apply the crystal growth apparatus 100 to the crystal production method. Referring to FIG. 1A and FIG. 3, the steps of the crystal manufacturing method include the following steps: performing a preparation step of providing the crystal growth apparatus 100 as described above (here, the crystal growth apparatus 100 shown in FIG. 1A is taken as an example), and A raw material is contained in the crucible 1 (not shown). Thereafter, the heat reflecting rings 4 are suspended from the crucible cover 2 through the hanging unit 5, and the heat insulating unit 3 is mounted on the crucible lid 2, and then the crucible lid 2 is mounted on the crucible 1 The heat reflecting rings 4 are located in the accommodating space 11. The material of the raw material may be alumina, tantalum or other materials, and is not limited herein.

A heating step is performed: heating of the crystal growth apparatus 100 to melt the raw material to form a molten soup 200. In the heating process of the crystal growth device 100, The heat reflecting rings 4 are deformed by heat, so that the first angle between each heat reflecting ring 4 and the crucible cover 2 is gradually changed to the second angle, thereby adjusting the vertical temperature distribution and level of the surface of the molten stone 200. The temperature ladder is distributed.

In more detail, when the first angle between each heat reflecting ring 4 and the crucible cover 2 gradually changes to the second angle, the inner diameter of each heat reflecting ring 4 is from the adjacent crucible cover 2 away from the crucible lid The direction of 2 gradually increases, and the melt 200 condenses on the condensate 201 of each heat reflecting ring 4 due to evaporation, and slides along the surface of each heat reflecting ring 4 to the outer portion of the molten stone 200, thereby preventing condensation of impurities from falling. The problem arises.

Thereafter, the molten crystal 200 is subjected to a seeding step to form a crystal (not shown), wherein the crystal growth unit 100 does not have the inside and the outside of the crucible 1 due to the arrangement of the heat insulating unit 3 and the heat reflecting ring 4. The sudden drop in temperature occurs to achieve the effect of improving crystal quality. The specific seeding step is a common technical means in the industry and will not be described in detail here.

Incidentally, the number of layers of the heat insulating sheet 31, the number of layers of the heat reflecting ring 4, and the angle between the heat reflecting ring 4 and the crucible lid 2 can be adjusted in accordance with the distribution of the surface temperature of the melt 200. .

[Possible effects of the examples]

According to an embodiment of the invention, the above-mentioned crystal growth device and crystal manufacturing method can improve the adjustable interval of the process parameters, thereby controlling the distribution of the temperature gradient on the molten steel surface, thereby reducing the probability of rapid growth of the shoulder expansion, and reducing the thermal stress of the crystal. Focus on improving the quality of the crystal. Furthermore, the crystal growth device can be acutely angled with the crucible lid through the heat reflecting ring, and the inner diameter of each heat reflecting ring is gradually increased from the adjacent crucible lid away from the crucible lid to avoid the influence of condensation impurities. The effect of crystal growth.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

100‧‧‧ crystal growth device

1‧‧‧坩锅

11‧‧‧ accommodating space

2‧‧‧坩 pot lid

21‧‧‧ openings

22‧‧‧through holes

3‧‧‧Insulation unit

31‧‧‧Insulation

4‧‧‧Hot reflection ring

41‧‧‧ first side

42‧‧‧ second side

43‧‧‧Extension

44‧‧‧through hole

5‧‧‧ hanging unit

51‧‧‧Fixed parts (eg screws)

52‧‧‧ Positioning parts (eg nuts)

200‧‧‧ molten soup

201‧‧‧Condensate

Fig. 1A is a plan view (I) of the crystal growth apparatus of the present invention when it is not heated.

FIG. 1B is a partial perspective view of FIG. 1A.

Fig. 1C is a plan view (2) of the crystal growth apparatus of the present invention when it is not heated.

Fig. 1D is a plan view (3) of the crystal growth apparatus of the present invention when it is not heated.

2A is a schematic plan view (I) of the crystal growth apparatus of the present invention after heating.

2B is a plan view (2) of the crystal growth apparatus of the present invention after heating.

Figure 3 is a schematic view showing the steps of a method for producing a crystal of the present invention.

100‧‧‧ crystal growth device

1‧‧‧坩锅

11‧‧‧ accommodating space

2‧‧‧坩 pot lid

21‧‧‧ openings

22‧‧‧through holes

3‧‧‧Insulation unit

31‧‧‧Insulation

4‧‧‧Hot reflection ring

41‧‧‧ first side

42‧‧‧ second side

44‧‧‧through hole

5‧‧‧ hanging unit

51‧‧‧Fixed parts (eg screws)

52‧‧‧ Positioning parts (eg nuts)

200‧‧‧ molten soup

201‧‧‧Condensate

Claims (9)

A crystal growth apparatus comprising: a crucible; a crucible lid defining an opening, the crucible lid being mounted on the crucible, and the crucible is surrounded by the crucible lid to define an accommodation space, The accommodating space is connected to the outside through the opening; an insulating unit is disposed on the outer surface of the crucible lid; and a plurality of heat reflecting rings are disposed in the accommodating space and are respectively suspended from the accommodating space a heat sinking ring, and two adjacent heat reflecting rings are spaced apart, and a first angle is formed between the heat reflecting ring and the crucible cap, and the first angle is a flat angle, and the heat reflecting rings are The deformation can be generated during the heating of the crystal growth device such that the first angle between each heat reflecting ring and the crucible cover can be changed to a second angle, and the second angle is an acute angle. The crystal growth device of claim 1, further comprising a plurality of rod-shaped fixing members, wherein the fixing members are mounted on the crucible cover, and the heat reflecting rings are positioned on the fixing members and suspended Hanging on the crucible lid, and leaving a gap between the heat reflecting rings and the fixing members to allow an angle change between the heat reflecting rings and the crucible lid. The crystal growth device of claim 2, further comprising a plurality of positioning members, each of the heat reflecting rings being formed with a plurality of through holes, each of the through holes having a size smaller than a size of each of the positioning members, the heat reflection The ring is suspended from the crucible cover by the cooperation of the positioning members and the fixing members. The crystal growth apparatus of claim 2, wherein each heat reflection ring is substantially plate-shaped and has a first surface and a second surface opposite to each other during heating of the crystal growth apparatus. The first side of the heat reflection ring and the first The two sides are respectively subjected to different thermal stresses to generate different thermal expansions, so that the first angle between each heat reflecting ring and the crucible lid can be changed to the second angle. The crystal growth apparatus of any one of claims 1 to 4, wherein the heat reflection rings are made of tantalum, tungsten, or molybdenum. The crystal growth apparatus according to any one of claims 1 to 4, wherein, when the second reflection angle is formed between the heat reflection ring and the crucible lid, the inner diameter of each heat reflection ring is The crucible cover is gradually increased in a direction away from the crucible lid. The crystal growth unit according to any one of claims 1 to 4, wherein the heat insulation unit has a plurality of layers of annular heat insulation sheets, and the heat insulation sheet layers are sequentially stacked on the crucible lid On the outer surface, the inner diameters of the heat insulating sheets are increased step by layer from the direction of the crucible cover away from the crucible lid. A crystal manufacturing method, comprising the steps of: providing the crystal growth apparatus according to claim 1; storing a raw material in the crucible; suspending the heat reflection rings under the crucible lid, and The heat insulating unit is mounted on the crucible lid, and then the crucible lid is mounted on the crucible, the heat reflecting rings are located in the receiving space; and the heating of the crystal growth device is performed to The raw material is melted to form a molten soup. During the heating of the crystal growth device, the heat reflecting rings are deformed by heat, so that the first angle between each heat reflecting ring and the crucible cap is gradually changed. The second angle to an acute angle, thereby adjusting the vertical temperature distribution and the horizontal temperature distribution of the molten stone surface. The crystal manufacturing method of claim 8, wherein the first angle between each heat reflecting ring and the crucible lid gradually changes to At the second angle, the inner diameter of each heat reflecting ring gradually increases from the direction of the crucible cover away from the crucible lid, and the melt is condensed by condensation on the condensation of each heat reflecting ring, along the per The surface of a heat reflecting ring slides down to the outer portion of the melt.