TWI747780B - Crystal growth furnace - Google Patents

Abstract

A crystal growth furnace. The furnace cavity of the crystal growth furnace is provided with an air inlet channel above the crucible, the upper exhaust member has a connected flow channel and an air outlet, the flow channel has an open side surrounding the air inlet channel, and the guide member and the upper exhaust part is connected and arranged on the open side of the flow channel. The guide member has a first air inlet and at least two second air inlets. The first air inlet is arranged on the side away from the air outlet, and a longitudinal reference plane passes through the first air inlet and the air outlet, the guide member can be divided into a first section and a second section by the longitudinal reference plane, at least two second air inlets are respectively arranged on the first section and the second section, and the opening area of the first air inlet is larger than the opening area of ​​at least two second air inlets. The gas in the furnace cavity is pumped out of the furnace cavity through the flow guide to the flow channel of the upper exhaust member through the air extraction device.

Description

Crystal growth furnace

The invention relates to a crystal growth furnace; in particular, it refers to a crystal growth furnace that can make the gas flow uniform in the furnace cavity.

In a typical CZ method (Czochralski) process, the silicon material is placed in a crucible, and the silicon material is melted into liquid silicon at a temperature of about 1416°C, and then a silicon seed crystal with a predetermined crystal orientation is lowered to contact the liquid silicon Under proper temperature control, the liquid silicon forms a single crystal on the silicon seed crystal with a predetermined crystalline orientation with the silicon seed crystal. Then, the silicon seed crystal and the crucible are rotated and slowly pulled up so that the silicon A silicon crystal rod is formed under the seed crystal.

It is known that in the process of crystal growth, inert gas must be introduced into the crystal growth furnace and the gas in the furnace cavity must be discharged to achieve the purpose of cooling and removing impurities. The gas of the conventional crystal growth furnace passes through the upper part of the furnace body of the crystal growth furnace The gas inlet is introduced into the gas, and a gas outlet is opened from the furnace body under the crystal growth furnace to take out the gas in the furnace cavity. However, this design can only discharge the gas near the gas outlet of the lower furnace body. For the crystal growth furnace The impurities around the crucible in the inner crucible are not easy to be discharged with the gas, so it is easy to cause impurities to deposit and affect the quality of the silicon ingot. In addition, this exhaust design is also easy to make the air flow around the crucible turbulent and uneven, which will cause the crucible to dissipate heat. It is undesirable and affects the uniformity of the crystal grain size of the silicon crystal rod. Therefore, how to improve the uniformity of the air flow in the furnace cavity of the crystal growth furnace and effectively discharge the impurities around the crucible out of the furnace cavity is an urgent problem to be solved.

In view of this, the object of the present invention is to provide a crystal growth furnace, which can improve the uniformity of the air flow in the furnace cavity of the crystal growth furnace and effectively discharge the impurities around the crucible from the furnace cavity.

In order to achieve the above-mentioned object, the present invention provides a crystal growth furnace connected to an exhaust device, the exhaust device includes an exhaust pipe, the crystal growth furnace includes a furnace body, a crucible, an upper exhaust and a The flow guide, the furnace body has a furnace cavity; the crucible is arranged in the furnace cavity, and the furnace cavity has an air inlet channel above the crucible; the upper exhaust member is arranged in the furnace cavity, and the upper row The gas element has a connected flow channel and an air outlet, the flow channel and the air outlet are located above the crucible, the flow tool has an open side surrounding the air inlet channel, and the exhaust pipe communicates with the air outlet; the guide The flow element is connected to the upper exhaust element and is arranged on the open side of the flow channel. The flow guide has a first air inlet and at least two second air inlets, and the first air inlet is arranged far away from the air outlet One side of, defines a longitudinal reference plane passing through the first air inlet and the air outlet, the guide piece can be divided into a first section and a second section by the longitudinal reference plane, the at least two second air inlets Respectively disposed in the first section and the second section, the opening area of the first air inlet is larger than the opening area of the at least two second air inlets; the gas in the furnace cavity is respectively passed through the diversion device through the air extraction device After the first air inlet hole and the at least two second air inlet holes of the upper exhaust member are drawn to the flow channel of the upper exhaust member, the furnace cavity is extracted through the air outlet and the exhaust pipe of the upper exhaust member.

The effect of the present invention is that through the arrangement of the guide element and the arrangement position of the air outlet, the gas in the furnace cavity can flow into the upper exhaust part through the first air inlet and the at least two second air inlets. The flow rate of the flow channel is evenly distributed, so that the uniformity of the air flow in the crystal growth furnace cavity can be improved and the impurities around the crucible can be effectively discharged from the furnace cavity.

In order to explain the present invention more clearly, a few preferred embodiments are listed in detail in conjunction with the drawings as follows. Please refer to FIG. 1, which is the first preferred embodiment of the crystal growth furnace 1 of the present invention, including a furnace body 10, a crucible 20, a heating device 30, a lifting device 40, an upper exhaust 50 and a The flow guide 60, the furnace body 10 has a furnace cavity R, the crucible 20 is arranged in the furnace cavity R for accommodating the raw material for crystal growth, and the heating device 30 is arranged on the periphery of the side of the crucible 20. To heat the crucible 20, the lifting device 40 is connected with a seed crystal to lower the seed crystal to the surface of the crucible 20 containing liquid silicon, and slowly raise the seed crystal with an appropriate pull-off rate to perform the crystal growth process .

A heat shield 70 is arranged in the furnace chamber R, and the heat shield 70 is arranged in a cone shape above the crucible 20. The furnace chamber R has an air inlet channel T1 located above the crucible 20 for supplying from the outside of the furnace chamber R A gas such as an inert gas is input, the heat shield 70 is arranged around the gas inlet channel T1 and the gas inlet channel T1 passes through the opening at the bottom of the heat mask 70. The upper exhaust member 50 is arranged in the furnace cavity R, and the upper exhaust member 50 is arranged around the furnace wall of the furnace body 10, and the upper exhaust member 50 has a communicating flow channel 501 and an air outlet 502 The flow channel 501 and the air outlet 502 are located above the crucible 20, the flow channel 501 has an open side 501a surrounding the air inlet channel T1, and the flow guide 60 is connected to the upper exhaust part 50 and is disposed on the The open side 501 a of the flow channel 501 closes the open side 501 a, and the air guide 60 has a first air inlet 61 and four second air inlets 62. The crystal growth furnace 1 is connected to an exhaust device, which includes an exhaust pipe 80 and an exhaust device. The exhaust pipe 80 is arranged on the upper part of the furnace body and located at a position higher than the crucible 20. One end of the exhaust pipe 80 communicates with the air outlet 502, and the other end communicates with the air extraction device, whereby the air in the furnace chamber R can be made to pass through the first air inlet hole of the guide 60 through the air extraction device 61 and the second air inlets 62 are drawn to the flow passage 501 of the upper exhaust member 50, and then drawn out of the furnace cavity through the air outlet 502 of the upper exhaust member 50 and the exhaust pipe 80.

Please cooperate with Figures 1 to 3, it is further explained that the first air inlet 61 is disposed on a side away from the air outlet 502, and defines a longitudinal reference plane S1 passing through the first air inlet 61 and the air outlet 502, the The air guide 60 can be divided into a first section 601 and a second section 602 by the longitudinal reference plane S1. The second air inlets 62 are provided in a group of two in the first section 601 and the second section 601 respectively. Two sections 602, and the opening area of the first air inlet 61 is greater than the opening area of the second air inlets 62, so that the opening area of the first air inlet 61 is larger than that of the first air inlets through the guide 60 The design of the opening area of the two air inlets 62 and the setting position of the air outlet 502 enables the gas in the furnace chamber R to flow into the upper exhaust member 50 through the first air inlet 61 and the second air inlets 62 In the flow channel 501, the flow velocity at the first air inlet 61 and the air outlet 502 in the flow channel 501 is evenly distributed and the impurities around the crucible 20 are effectively discharged from the furnace cavity R. In addition, the second inlets The arrangement of the air hole 62 can accelerate the exhaust of the gas in the furnace cavity R, and solve the problem of uneven gas flow velocity distribution caused by the arrangement of a single air hole in the conventional crystal growth furnace.

In this embodiment, four second air inlet holes 62 are taken as an example. In other embodiments, it is not excluded that the number of second air inlet holes is two, three, or more than four. For example, When the number of second air inlets is two, a second air inlet can be provided on the first section and the second section respectively, and when the number of second air inlets is three, it can be One second air inlet hole is provided on the section and two second air inlet holes are provided on the second section, which can also achieve the above-mentioned making the flow rate of the gas in the furnace chamber R into the flow channel 501 of the upper exhaust member 50 uniform. The effect of distribution.

In this embodiment, the flow channel 501 is annular, the air outlet 502 is arranged above the flow channel 501, the flow guide 60 is annular, and the height H of the flow guide 60 is 50~150mm, which is more Preferably it is 55~120 mm, the thickness T of the air guide 60 is 10~20mm, preferably 11~18.5 mm, the surface area A of the ring wall of the air guide 60 and the first air inlet 61 and these The ratio of the total opening area of the second air inlet 62 is 10:1-20:1, preferably 12:1-17:1. A horizontal reference plane S2 is defined to pass through the first air inlet 61 and each of the second air inlets 62, and the horizontal reference plane S2 intersects both sides of the hole wall of the first air inlet 61 at a first point P1 and a second Two points P2, the angle θ1 between the first point P1 and the second point P2 and the line of the guide 60 around a center C is between 35 degrees and 55 degrees, preferably between 37 degrees and 45 degrees In between, the horizontal reference plane S2 and the two sides of each second air inlet 62 intersect at a third point P3 and a fourth point P4, the third point P3 and the fourth point P4 are connected to the center C The angle θ2 of the line is between 3 degrees and 30 degrees, preferably between 3 degrees and 25 degrees. In this embodiment, the third point P3 and the fourth point P4 of each second air inlet 62 The angle θ2 between the line with the center C is a small hole 622 between 3 degrees and 10 degrees. Two adjacent first air inlet holes 61 and one second air inlet hole 62 intersect the horizontal reference plane S2 on a side close to each other at a fifth point P5 and a sixth point P6, and two adjacent ones The two second air inlet holes 62 on the side close to each other and the horizontal reference plane S2 also intersect at a fifth point P5 and a sixth point P6, respectively, the fifth point P5 and the sixth point P6 and the center The included angle θ3 of the C connection is between 20 degrees and 55 degrees, preferably between 25 degrees and 25.5 degrees. Through the setting of the aforementioned angles θ1, θ2, θ3, the size and arrangement position of the first air inlet 61 and the second air inlet 62 can be defined, thereby achieving an optimal configuration for uniform gas flow velocity distribution.

In this embodiment, the second air inlet holes 62 are illustrated by using four small holes 622 with the same opening area as an example. In practice, the second air inlet holes 62 can satisfy at least one of the at least two second air inlet holes. The opening area of one is different from the opening area of the other of the at least two second air inlet holes. For example, the second air inlet holes 62 can also include a plurality of medium-sized holes 621 and a plurality of small-sized holes. Holes 622, such as one first air inlet 61, two medium holes 621 and two small holes 622 shown in FIG. 4, wherein the opening area of the medium hole 621 is larger than the opening area of the small hole 622, and the third The angle θ2 between the line between the point P3 and the fourth point P4 and the center C is between 3 degrees and 10 degrees. The included angle θ2 is between 15 degrees and 30 degrees, and the opening area between each small hole 622 can also be different, and the opening area between each medium hole 621 can also be different. It should be noted that the second air inlet holes 62 can also include a plurality of medium-sized holes 621, such as one first air inlet hole 61 and six medium-sized holes 621 shown in FIG. In order to compare the gas flow rate simulation photos of the size and arrangement of the first gas inlet hole 61 and the second gas inlet holes 62 as shown in FIG. 2, it can be seen from the simulation result of FIG. 7 that the gas flow rate is in the flow channel 501 The gas flow velocity difference between the first gas inlet 61 and the gas outlet 502 is small, and the gas velocity in the flow channel 501 can be kept evenly distributed.

Please cooperate with FIG. 6, which shows the crystal growth furnace 2 of the second preferred embodiment of the present invention. The crystal growth furnace 2 has substantially the same structure as the crystal growth furnace 1 of the above-mentioned first preferred embodiment, and will not be repeated here. The difference is that the crystal growth furnace 2 includes a lower exhaust passage T2, which is disposed in the furnace chamber R and located below the crucible 20, and the lower exhaust passage T2 is connected to an external air extraction device, thereby passing through the external The air extraction device can exhaust the gas in the furnace cavity R from the lower exhaust passage T2. In addition, the guide 60 of the crystal growth furnace 2 of the second preferred embodiment of the present invention includes a plurality of baffles 90, which can be controlled to shield or open the first air inlet 61 and The openings of the second air inlets 62. When the first air inlet 61 or each of the second air inlets 62 is shielded by the baffle 90, the gas in the furnace chamber R cannot be shielded by the baffle 90. An air inlet 61 or a second air inlet 62 flows into the flow channel 501 to adjust the flow direction of the internal air flow.

In summary, the design of the opening area of the air guide 60 and the first air inlet 61 of the present invention is larger than the opening area of the second air inlets 62 and the setting position of the air outlet 502, which can make the furnace cavity When the gas in R flows into the flow passage 501 of the upper exhaust member 50 through the first gas inlet 61 and the second gas inlets 62, the flow velocity is evenly distributed, and the impurities around the crucible 20 are effectively discharged from the furnace cavity R , In order to improve the problem of uneven gas flow rate distribution caused by the setting of a single vent hole in the conventional crystal growth furnace.

The above are only the preferred and feasible embodiments of the present invention. Any equivalent changes made by applying the specification of the present invention and the scope of the patent application should be included in the patent scope of the present invention.

[this invention] 1,2: Crystal growth furnace 10: Furnace 20: Crucible 30: heating device 40 lifting device 50: Upper exhaust 501: runner 501a: open side 502: air outlet 60: deflector 601: First paragraph 602: second paragraph 61: The first air inlet 62: second air inlet 621: Medium hole 622: small hole 70: Heat mask 80: Exhaust pipe 90: bezel C: Center H: height P1: The first point P2: The second point P3: third point P4: Fourth point P5: The fifth point P6: Sixth point R: Oven cavity S1: Longitudinal reference plane S2: Horizontal reference plane T1: Inlet channel T2: Lower exhaust channel T: thickness A: Surface area

Fig. 1 is a schematic diagram of a crystal growth furnace according to a first preferred embodiment of the present invention. 2 is a schematic cross-sectional view of the crystal growth furnace of the above preferred embodiment on a transverse reference plane. Fig. 3 is a perspective view of the air guide of the above-mentioned preferred embodiment. 4 is a schematic cross-sectional view of another preferred embodiment on a transverse reference plane. Fig. 5 is a schematic cross-sectional view of another preferred embodiment on a transverse reference plane. Fig. 6 is a schematic diagram of a crystal growth furnace according to a second preferred embodiment of the present invention. Fig. 7 is a simulation photo of the gas flow rate of the first preferred embodiment of the present invention.

1: Crystal growth furnace

10: Furnace

20: Crucible

30: heating device

40: Lifting device

50: Upper exhaust

501: runner

501a: open side

502: air outlet

60: deflector

61: The first air inlet

62: second air inlet

70: Heat mask

80: Exhaust pipe

H: height

R: Oven cavity

S2: Horizontal reference plane

T1: Inlet channel

Claims (10)

A crystal growth furnace is connected with an air extraction device, the air extraction device includes an exhaust pipe, and the crystal growth furnace includes: A furnace body with a furnace cavity; A crucible arranged in the furnace cavity, the furnace cavity has an air inlet channel located above the crucible; An upper exhaust part is arranged in the furnace cavity, the upper exhaust part has a communicating flow channel and an air outlet, the flow channel and the air outlet are located above the crucible, and the flow part has an open side surrounding the An air inlet channel, the exhaust pipe communicates with the air outlet; and A flow guide connected to the upper exhaust part and arranged on the open side of the flow channel, the flow guide has a first air inlet hole and at least two second air inlet holes, the first air inlet hole is arranged far away One side of the air outlet defines a longitudinal reference plane passing through the first air inlet and the air outlet. The guide element can be divided into a first section and a second section by the longitudinal reference plane. The at least second section Two air inlets are respectively arranged in the first section and the second section, and the opening area of the first air inlet is larger than the opening area of the at least two second air inlets; After the gas in the furnace cavity is drawn to the flow channel of the upper exhaust member through the first air inlet hole and the at least two second air inlet holes of the guide member through the air pumping device, and then exhausted through the upper exhaust member The air outlet and the exhaust pipe of the component are drawn out of the furnace cavity. The crystal growth furnace according to claim 1, wherein the guide member is ring-shaped, and the ratio of the surface area of the ring wall of the guide member to the sum of the opening area of the first air inlet hole and the at least two second air inlet holes is 10 :1~20:1. The crystal growth furnace according to claim 2, wherein a horizontal reference plane is defined to pass through the first gas inlet hole and each of the second gas inlet holes, and the horizontal reference plane intersects both sides of the first gas inlet hole wall at a first gas inlet hole. One point and a second point. The angle between the first point and the second point and the line connecting the air guide around a center is between 35 degrees and 55 degrees. The horizontal reference plane and each of the second entrances The two sides of the air hole intersect at a third point and a fourth point, and the angle between the third point and the fourth point and the center is between 3 degrees and 30 degrees. The crystal growth furnace according to claim 3, wherein two adjacent first gas inlet holes and one second gas inlet hole or two adjacent second gas inlet holes are on the side close to each other and the horizontal reference plane Intersect at a fifth point and a sixth point respectively, and the angle between the fifth point and the sixth point and the center is between 20 degrees and 55 degrees. The crystal growth furnace according to claim 1, wherein the height of the deflector is 50~150mm. The crystal growth furnace according to claim 1, wherein the thickness of the deflector is 10-20 mm. The crystal growth furnace according to claim 1, wherein the opening area of at least one of the at least two second gas inlet holes is different from the opening area of the other one of the at least two second gas inlet holes. The crystal growth furnace according to claim 1, wherein the deflector includes a plurality of baffles, and the baffles can be controlled to shield or open the openings of the first air inlet and the at least two second air inlets. The crystal growth furnace according to claim 2, wherein the flow channel is annular, and the air outlet is arranged above the flow channel. The crystal growth furnace according to claim 1, including a lower exhaust channel, which is arranged in the furnace cavity and located below the crucible.

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