CN213476156U

CN213476156U - Semiconductor crystal manufacturing apparatus and piping structure thereof

Info

Publication number: CN213476156U
Application number: CN202021941143.XU
Authority: CN
Inventors: 小川福生; 鸣嶋康人; 酒谷和幸; 川上泰史; 鸭川诚; 四井拓也
Original assignee: Sumco Corp
Current assignee: Sumco Corp
Priority date: 2019-09-20
Filing date: 2020-09-08
Publication date: 2021-06-18
Anticipated expiration: 2030-09-08
Also published as: CN112538655A; JP2021046344A

Abstract

A semiconductor crystal manufacturing apparatus of the present application includes 1 st to 4 th exhaust ports for exhausting gas introduced into a chamber for manufacturing a semiconductor crystal, individual exhaust pipes (31A to 31D) each having one end connected to each of the 1 st to 4 th exhaust ports, respectively, and a coupling pipe (32) connected to each other end of the individual exhaust pipes (31A to 31D). A 2 nd joint part from each of the 1 st to 4 th exhaust ports to the joint pipe (32) through each of the corresponding individual exhaust pipes (31A to 31D)(C₂₁) Are all substantially equal.

Description

Semiconductor crystal manufacturing apparatus and piping structure thereof

Technical Field

The present invention relates to a semiconductor crystal manufacturing apparatus for manufacturing a semiconductor crystal by a single crystal growth method using, for example, the Czochralski method (hereinafter, referred to as the "CZ method") or the Floating zone method (hereinafter, referred to as the "FZ method").

Background

In the CZ method, a silicon single crystal is pulled from a silicon melt melted in a crucible provided in a chamber. In the production process, oxygen (O)₂) From silicon dioxide (SiO)₂) The crucible as a component is dissolved out and reacts with the silicon melt to form silicon oxide (SiOx) or silicon dioxide (SiO)₂)。

The silicon oxide (SiOx) or the silicon dioxide (SiO)₂) Evaporating from the surface of the silicon melt. Silicon oxide (SiOx) and silicon dioxide (SiO) evaporated from the surface of the silicon melt₂) And the later-described dopant, the term "evaporant" is used.

In the silicon oxide (SiOx), x is 0 < x < 2. The reason why the silicon oxide (SiOx) is formed is that oxygen (O) is not sufficiently contained in comparison with silicon atom (S)₂) Since the silicon atoms (S) are present in the silicon melt and in the atmosphere in the chamber, the silicon atoms (S) are not completely oxidized.

The evaporant reaches the inner wall surface of the cavity above the surface of the silicon melt, and a part of the evaporant adheres thereto. When the deposit falls and melts into the silicon melt and enters the silicon single crystal being pulled, there is a possibility that defects (for example, dislocation) occur in the silicon single crystal being produced.

In order to prevent such a problem, in a semiconductor crystal manufacturing apparatus, an inert gas is introduced from a gas inlet provided above a chamber, and the pressure in the chamber is maintained at a low pressure of several thousand Pa by an exhaust port provided at the bottom of the chamber, an exhaust pipe connected to the exhaust port, and an exhaust device, and the inert gas and an evaporant are exhausted to the outside of the chamber.

Some conventional semiconductor crystal manufacturing apparatuses include: a plurality of exhaust ports are provided in the chamber bottom wall, each exhaust port is connected to a plurality of exhaust pipes disposed substantially vertically below the exhaust port, and the exhaust pipes are connected to one another in front of the other exhaust pipe and the pressure control device (see, for example, document 1: japanese patent No. 4423805 (fig. 1 and 5)).

The evaporant reaching the exhaust pipe from the chamber in the high-temperature atmosphere is gradually cooled as it passes through the exhaust pipe, and a part of the evaporant is discharged to the outside, but a part of the evaporant adheres to the inner wall surface of the exhaust pipe and accumulates. The deposits on the inner wall surface of the exhaust pipe increase the thickness of the silicon single crystal as the number of pulling times increases.

In a state where the deposit adheres to the inner wall surface of the exhaust pipe, various problems as described below may occur.

(1) The deposit flows back into the chamber and mixes with the silicon melt, and the produced silicon single crystal is defective (e.g., dislocation occurs).

(2) Since the exhaust resistance of the exhaust pipe having a smaller inner diameter due to the deposit becomes large, the pressure in the chamber is difficult to control, and the pressure in the chamber tends to fluctuate greatly. This adversely affects the conditions for pulling the silicon single crystal, and the deposits detached from the inner wall surface of the exhaust pipe intrude into the equipment (for example, vacuum pump) located downstream of the exhaust pipe and damage the equipment.

(3) In order to impart desired properties to a silicon single crystal, a dopant may be added to a silicon melt. Examples of the dopant include n-type dopants represented by arsenic (As), phosphorus (P), and antimony (Sb), and P-type dopants represented by boron (B) and aluminum (Al).

Since the n-type dopant has a boiling point lower than the melting point of silicon, it is easily evaporated from the surface of the silicon melt in the process of producing the silicon single crystal. As a result, the concentration of the n-type dopant in the silicon melt is lower than a predetermined value, and the desired properties (for example, resistivity) may not be obtained in the produced silicon single crystal. In order to prevent such a problem, when the n-type dopant is added, the pressure in the chamber is set higher than the low pressure of several thousand Pa.

However, the pressure in the chamber is set to a low pressure of several thousand Pa in order to prevent the evaporant evaporated from the surface of the silicon melt from reaching the inner wall surface of the chamber. If the pressure in the chamber is set high, the concentration of the evaporant in the exhaust pipe increases. The amount of the deposit on the inner wall surface of the exhaust pipe is larger than that in the case where the dopant is not added or the p-type dopant is added. Therefore, the possibility of the problems (1) and (2) is further increased.

In the conventional technique described in document 1, distances from the respective exhaust ports provided in the bottom wall of the chamber to the pressure control device via the corresponding exhaust pipes are different. From the findings, when the length of the exhaust pipe is sufficiently long, the exhaust velocity in the exhaust pipe is approximately inversely proportional to the length of the exhaust pipe. Therefore, in the conventional technique described in document 1, the exhaust velocities in the exhaust pipes are also different. As a result, for example, in the portion where the exhaust pipes are joined, the flow of the inert gas is disturbed, and the problems shown in (1) to (3) above occur. However, means for solving these problems are not disclosed in the aforementioned document 1.

SUMMERY OF THE UTILITY MODEL

The present invention is an example of solving the various problems described above, and an object of the present invention is to provide a semiconductor crystal manufacturing apparatus capable of solving these problems.

In order to solve the above problem, the distances from the respective exhaust ports provided in the bottom of the chamber to the joint portion where the respective joint pipes are joined to one another for connection to the exhaust device may be equal to each other, via the plurality of individual exhaust pipes connected to the corresponding exhaust ports and the plurality of joint pipes connected to the individual exhaust pipes. In this case, it is preferable that at least the exhaust pipes directly connected have the same or symmetrical shape and the same inner diameter.

However, since a drive mechanism for rotating and raising/lowering the crucible is provided at the center of the bottom of the chamber, it is necessary to avoid interference with the crucible. If the length of the exhaust pipe is unnecessarily increased in order to avoid interference with the drive mechanism, a large installation space for the exhaust pipe is required, installation cost is also increased, and an exhaust device having a strong suction force is required to suck the inert gas and the adhering substance through the longer exhaust pipe.

Here, the findings of the results obtained by the repeated intensive studies of the present invention will be described with reference to fig. 1. FIG. 1 is a view showing that 8 exhaust ports EH are formed in the bottom of a chamber₁~EH₈An example of the case (1).

First, each exhaust port EH₁~EH₈Are formed at symmetrical positions with respect to the central axis of the driving mechanism at the bottom of the chamber. Each end and the corresponding exhaust port EH₁~EH₈Respectively connected 8 individual exhaust pipes EP₁~EP₈With 2 adjacent individual Exhaust Pipes (EP)₁，EP₂)、(EP₃，EP₄)、(EP₅，EP₆)、(EP₇，EP₈) Paired (paired).

Paired individual Exhaust Pipes (EP)₁，EP₂)、(EP₃，EP₄)、(EP₅，EP₆)、(EP₇，EP₈) At each joint part C₁₁~C₁₄In the coupled state, the coupling part C passes through the corresponding coupling part C relative to the central axis passing through the driving mechanism₁₁~C₁₄The reference surface(s) of (2) have the same or symmetrical shape such as a symmetrical shape, have the same inner diameter, and have the same size. In the example of FIG. 1, the exhaust pipe EP₁And an exhaust pipe EP₂Forming a substantially V-shape. In FIG. 1, for example, the exhaust port EH₁To the 1 st binding site C₁₁Mark of one line crossing the line of (a), and the exhaust port EH₂To the 1 st binding site C₁₁Is indicated by a line crossing, their lengths being equal, i.e. indicating the exhaust pipe EP₁Length of (2) and exhaust pipe EP₂Are equal in length.

Paired individual Exhaust Pipes (EP)₁，EP₂)、(EP₃，EP₄)、(EP₅，EP₆)、(EP₇，EP₈) So that the other ends are at the 1 st bonding part C₁₁、C₁₂、C₁₃、C₁₄Are respectively combined. Two adjacent 1 st joint parts (C)₁₁、C₁₂)、(C₁₃、C₁₄) In pairs. Paired No. 1 binding moieties (C)₁₁、C₁₂) With the 1 st junction pipe CP₁₁And (4) connecting. Paired No. 1 binding moieties (C)₁₃、C₁₄) With the 1 st junction pipe CP₁₂And (4) connecting.

No. 1 junction tube CP₁₁Having one end thereof corresponding to the 1 st combining part C₁₁Connected branch part B₁₁One end of the first connecting part C is connected with the corresponding 1 st connecting part C₁₂Connected branch part B₁₂. Branch part B₁₁The other end of (B), branch part B₁₂And the other end of (2) and the 2 nd joint part C₂₁And (4) connecting. No. 1 junction tube CP₁₂Having one end thereof corresponding to the 1 st combining part C₁₃Connected branch part B₁₃One end of the first connecting part C is connected with the corresponding 1 st connecting part C₁₄Connected branch part B₁₄. Branch part B₁₃The other end of (B), branch part B₁₄And the other end of (2) and the 2 nd joint part C₂₂And (4) connecting.

No. 1 junction tube CP₁₁Relative to the central axis passing through the driving mechanism and passing through the 2 nd joint part C₂₁The reference surface of (b) has the same or symmetrical shape as the symmetrical shape. Branch part B₁₁And branch part B₁₂Have the same inner diameter and the same size. No. 1 junction tube CP₁₂Relative to the central axis passing through the driving mechanism and passing through the 2 nd joint part C₂₂The reference surface of (a) is the same or symmetrical shape as the symmetrical shape. Branch part B₁₃And branch part B₁₄Have the same inner diameter and the same size. In the example of FIG. 1, the 1 st bonding tube CP₁₁And CP₁₂A substantially V-shape is formed.

In FIG. 1, for example, the 1 st joint part C₁₁To the 2 nd binding site C₂₁The mark of two crossed threads and the 1 st joint C₁₂To the 2 nd binding site C₂₁The symbol of two lines crossing each other indicates that the lengths thereof are equal, i.e., the branch part B₁₁Length of (2) and branch part B₁₂Are equal in length.

Two adjacent 2 nd binding parts (C)₂₁、C₂₂) In pairs. Paired No. 2 binding parts (C)₂₁、C₂₂) With 2 nd junction pipe CP₂₁And (4) connecting. No. 2 junction pipe CP₂₁Has one end and a corresponding 2 nd combining part C₂₁Connected branch part B₂₁One end of the second connecting part C is connected with the corresponding 2 nd connecting part C₂₂Connected branch part B₂₂. Branch part B₂₁The other end of (B), branch part B₂₂And the other end of (3) and the 3 rd combining part C₃₁And (4) connecting. 3 rd binding part C₃₁With 3 rd combination pipe CP₃₁Is connected at one end. No. 3 junction tube CP₃₁The other end of the valve body is connected to an unillustrated exhaust device.

No. 2 junction pipe CP₂₁So as to pass through the 3 rd combining part C relative to the central shaft passing through the driving mechanism₃₁The same or symmetrical shape as the reference plane symmetrical shape of (2). Branch part B₂₁And branch part B₂₂Have the same inner diameter and the same size. In the example of FIG. 1, the 2 nd junction pipe CP₂₁Forming a substantially V-shape.

The 2 nd joint C in FIG. 1₂₁To the 3 rd binding part C₃₁Symbol of three crossed wires, and secondary connection part C₂₂To the 3 rd binding part C₃₁The three lines of (2) are marked with the same length, i.e., the branch part B₂₁Length of (2) and branch part B₂₂Are equal in length.

The above-described findings are generalized as follows.

Firstly, 2 is putⁿThe exhaust ports (n is an integer of 2 or more) are formed at symmetrical positions around the central axis of the drive mechanism at the bottom of the chamber, and 2 exhaust ports each having one end connected to each corresponding exhaust port are providedⁿIndividual exhaust pipes, and 2 connecting the other ends of a pair of adjacent individual exhaust pipes ^n-11 st combination part.

Next, set 2^n-k-1(k + 1) th joint part, 2^n-k-1The kth binding tube. Each of the kth joint pipes has a pair of branch portions, one end of each of the branch portions is connected to each of the adjacent pair of kth joint portions, and the other end of each of the branch portions is connected to the corresponding (k + 1) th joint portion by being joined thereto. k is a positive integer increasing one by one from 1 to (n-1). (k + 1) th joint part and (k + 1) th joint pipeAnd k increases from 1 to (n-1) one by one to constitute a piping portion. Then, the nth joining portion, which is the end of the piping portion, is connected to the exhaust device. Distances from each exhaust port to the n-th joint portion via the corresponding exhaust pipe are equal.

In this regard, it is considered that when the number of the exhaust ports is an odd number, 2ⁿIn the case of an even number (for example, 6) other than the above, the distances from the exhaust ports to the exhaust device via the corresponding exhaust pipes can be made equal. However, it is difficult to form the piping structure at the shortest distance while avoiding interference between each individual exhaust pipe and the drive mechanism.

In order to solve the above-mentioned problems, a semiconductor crystal manufacturing apparatus according to claim 1 is characterized by comprising 1 st, 2 nd, 3 rd and 4 th exhaust ports, 1 st, 2 nd, 3 rd and 4 th individual exhaust pipes, a 1 st joint part, a 2 nd joint part and a joint pipe, wherein the 1 st, 2 nd, 3 rd and 4 th exhaust ports discharge gas introduced into a cavity in which a semiconductor crystal is manufactured, the 1 st, 2 nd, 3 rd and 4 th individual exhaust pipes have respective one ends connected to the corresponding 1 st to 4 th exhaust ports, the 1 st joint part is formed by joining and connecting respective other ends of a pair of adjacent 1 st and 2 nd individual exhaust pipes, the 2 nd joint part is formed by joining and connecting respective other ends of a pair of adjacent 3 rd and 4 th individual exhaust pipes, and the joint pipe has a 1 st branch part, one end of which is connected to the 1 st joint part, And a 2 nd branch part having one end connected to the 2 nd joint part, wherein the other ends of the 1 st and 2 nd branch parts are connected to a 3 rd joint part, and distances from the 1 st to 4 th exhaust ports to the 3 rd joint part via the 1 st to 4 th individual exhaust pipes are substantially equal.

The invention according to claim 2 is the semiconductor crystal manufacturing apparatus according to claim 1, wherein the 1 st to 4 th exhaust ports are provided at symmetrical positions with respect to a center axis of a driving mechanism for rotating and lifting the crucible provided in the chamber, the pair of the 1 st and 2 nd individual exhaust pipes are symmetrical with respect to a 1 st reference plane passing through the center axis, the pair of the 3 rd and 4 th individual exhaust pipes are symmetrical with respect to the 1 st reference plane, and the pair of the 1 st and 2 nd individual exhaust pipes and the pair of the 3 rd and 4 th individual exhaust pipes are provided at symmetrical positions with respect to a 2 nd reference plane different from the 1 st reference plane passing through the center axis.

The semiconductor crystal manufacturing apparatus of claim 3 is characterized by comprising 2ⁿ(n is an integer of 2 or more) exhaust ports, 2ⁿIndividual exhaust pipes, 2^n-11 st binding part, 2^n-k-1{ k is a positive integer increasing one by one from 1 to (n-1) } number of (k + 1) -th binding moieties, 2^n-k-1A kth joint pipe, 2ⁿA plurality of (n is an integer of 2 or more) exhaust ports for exhausting gas introduced into a chamber for manufacturing a semiconductor crystal, the exhaust ports 2ⁿEach end of each individual exhaust pipe is connected to each corresponding exhaust port, 2^n-1The 1 st joint part is formed by joining and connecting the other ends of the adjacent pair of the individual exhaust pipes, and the 2 nd joint part^n-k-1The kth joint pipe has a pair of branch portions, one end of each of the branch portions is connected to each of the adjacent pair of kth joint portions, the other ends of the branch portions are connected to the corresponding (k + 1) th joint portion, and distances from the exhaust ports to the nth joint portion via the corresponding individual exhaust pipes are substantially equal.

The semiconductor crystal manufacturing apparatus of claim 4 is characterized by comprising a chamber, a crucible, a heater, and a heater 2ⁿ(n is an integer of 2 or more) exhaust gas conduits, 2ⁿAn exhaust port, 2ⁿIndividual exhaust pipes, 2^n-11 st binding part, 2^n-k-1{ k is a positive integer increasing one by one from 1 to (n-1) } number of (k + 1) -th binding moieties, 2^n-k-1A kth junction tube, the chamber being used for producing a semiconductor crystal, the crucible being provided in the chamber, the heater being disposed so as to surround the crucible and heating the crucible, the kth junction tube 2ⁿThe exhaust ducts are formed at the upper exhaust port for exhausting the gas introduced into the chamber from the upper part of the heater and the lower part of the corresponding upper exhaust port, and are connected to the lower exhaust port for exhausting the gas from the lower part of the heaterGeneral, the above 2ⁿAn exhaust port formed at the bottom of the chamber and connected to the lower end of each exhaust duct, 2ⁿEach end of each individual exhaust pipe is connected to each corresponding exhaust port, 2^n-1The 1 st joint part is formed by joining and connecting the other ends of the adjacent pair of the individual exhaust pipes, and the 2 nd joint part^n-k-1The kth joint pipe has a pair of branch portions, one end of each of the branch portions is connected to each of the adjacent pair of kth joint portions, the other ends of the branch portions are connected to the corresponding (k + 1) th joint portion, and distances from the upper end of each of the exhaust pipes to the nth joint portion via the corresponding individual exhaust pipe are substantially equal.

The 5 th utility model relates to the semiconductor crystal manufacturing apparatus of the 3 rd or 4 th utility model, characterized in that, the 2 nd utility modelⁿThe exhaust ports are provided at symmetrical positions with respect to a central axis of a drive mechanism for rotating and moving up and down the crucible provided in the chamber, two adjacent individual exhaust pipes are provided at symmetrical positions with respect to a reference plane passing through the central axis, and the other two adjacent individual exhaust pipes are provided at symmetrical positions with respect to a reference plane passing through the central axis and different from the reference plane.

The invention according to claim 6 relates to any one of the semiconductor crystal manufacturing apparatuses according to any one of the inventions 1 to 5, wherein a silicon single crystal to which an n-type dopant is added is manufactured.

The "distances from the 1 st to 4 th exhaust ports to the 3 rd joint portion via the corresponding 1 st to 4 th individual exhaust pipes" of the invention 1 are all physically completely equal, and it is impossible to make the distances by the dimensional tolerances of the individual exhaust pipes and the difference in the amount of material (welding material in the case of welding) when the individual exhaust pipes are joined to the joint pipe equal. The utility model discloses so that the exhaust velocity of the air current that flows in many blast pipes equals to the purpose, as long as can realize this purpose, then can allow the inequality of aforementioned distance. The same applies to the 3 rd and 4 th inventions.

Therefore, "substantially equal" in the 1 st, 3 rd and 4 th inventions means that the exhaust velocities of the airflows are not physically completely equal but are equal to such an extent that the exhaust velocities of the airflows are equal.

According to the utility model discloses, can make the exhaust velocity of the air current that flows in the many blast pipes that are connected correspondingly with setting up in a plurality of gas vents of chamber bottom equalize.

Drawings

Fig. 1 is a conceptual diagram illustrating an example of a piping structure of a semiconductor crystal manufacturing apparatus according to the present invention.

Fig. 2 is a conceptual diagram illustrating an example of the structure of a semiconductor crystal manufacturing apparatus according to embodiment 1 of the present invention.

Fig. 3 is a perspective view showing an example of a structure of a piping unit constituting the semiconductor crystal manufacturing apparatus shown in fig. 2.

Fig. 4 is a plan view showing an example of a structure of a piping section constituting the semiconductor crystal manufacturing apparatus shown in fig. 2.

FIG. 5 is a side view showing an example of the structure of a piping section constituting the semiconductor crystal manufacturing apparatus shown in FIG. 2.

Fig. 6 is a conceptual diagram illustrating an example of the structure of a semiconductor crystal manufacturing apparatus according to embodiment 2 of the present invention.

Fig. 7 is a cross-sectional view showing an example of the structure of the exhaust passage of the semiconductor crystal manufacturing apparatus according to embodiment 2 of the present invention.

Fig. 8 is a plan view showing an example of the structure of a pipe portion as a comparative example.

Fig. 9 is a side view showing an example of the structure of a pipe portion as a comparative example.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1.

Fig. 2 is a conceptual diagram illustrating an example of the structure of the semiconductor crystal manufacturing apparatus 1 according to embodiment 1 of the present invention. The semiconductor crystal manufacturing apparatus 1 manufactures a silicon single crystal by the CZ method. The semiconductor crystal manufacturing apparatus 1 includes a semiconductor crystal manufacturing unit 11 and a gas exhaust unit 12.

The semiconductor crystal manufacturing section 11 is disposed on the floor FC of the clean room CR. The semiconductor crystal manufacturing unit 11 includes a hollow cavity 21 having open upper and lower ends, a single crystal pulling unit 22 connected to the upper end of the cavity 21, and a gas introduction unit 23 for introducing an inert gas into the cavity 21. The chamber 21 accommodates a crucible 25 having a substantially bottomed cylindrical shape for storing the silicon melt M.

The chamber 21 houses a drive mechanism 51 for rotating and raising and lowering the crucible 25, a heater, not shown, disposed outside the crucible 25 at a predetermined interval to heat the silicon melt M, and a heat-insulating cylinder disposed outside the heater at a predetermined interval. The single crystal pulling section 22 dips a seed crystal, not shown, in the silicon melt M in the crucible 25, and then pulls the seed crystal by rotating the seed crystal in a predetermined direction.

A base plate (not shown) which forms the bottom of the chamber 21 and is placed on the floor surface FC, and 2 are formed to discharge the inert gas introduced into the chamber 21 to the outsideⁿ(n is an integer of 2 or more) exhaust ports 24, and in embodiment 1, 4 exhaust ports 24A to 24D are formed, respectively, so that n is 2. The cross-sectional shape of the exhaust ports 24A to 24D is substantially circular. In fig. 2, the exhaust ports 24A to 24D are shown directly on the floor surface FC and are linearly spaced at predetermined intervals. However, the exhaust ports 24A to 24D are actually formed above the respective corresponding individual exhaust pipes 31A to 31D (see fig. 4) on the upper surface of the substrate, and the respective corresponding individual exhaust pipes 31A to 31D are formed at positions substantially symmetrical to each other with reference to reference surfaces RT1 and RT2 which are perpendicular to each other through the central axis of the drive mechanism 51 in a plan view.

In fig. 2, the gas exhaust portion 12 is disposed under the floor FC of the clean room CR and the floor FP of the pump chamber PR. The exhaust ports 24A to 24D are provided in the lower opening of the floor FC of the substrate and the clean room CR. The lower ends of the exhaust ports 24A to 24D are connected with 2 corresponding to the exhaust ports 24A to 24DⁿIn embodiment 1, n is 2, that is, each end of the 4 individual exhaust pipes 31A to 31D is connected to the individual exhaust pipes 31.

The other ends of the individual exhaust pipes 31A to 31D are connected to a connecting pipe 32. The individual exhaust pipes 31A to 31D and the connecting pipe 32 constitute the piping part 13. The other end of the coupling pipe 32 is connected to the input end of the return bend 33. The output end of the return bend 33 is connected to one end of an exhaust pipe 34. The return trap 33 is configured to trap a peeled article that has been peeled off from the inner walls of the individual exhaust pipes 31A to 31D and has passed through the inside of the connection pipe 32.

The exhaust pipe 34 is disposed below the floor surface FC of the clean room CR and below the floor surface FP of the pump chamber PR. The exhaust pipe 34 branches into an exhaust pipe 35 and an exhaust pipe 36 at a position below the floor surface FP of the pump chamber PR. One end of the exhaust pipe 35 is connected to an input end of a main valve 37 which is opened when the silicon single crystal is produced and closed when the deposit is removed.

The output of the main valve 37 is connected to the input of a main pump 39 via an exhaust pipe 38. The output of the main pump 39 is connected to one end of an exhaust pipe 40, and the other end of the exhaust pipe 40 is connected to a scrubber 41. The main pump 39 is operated during the production of silicon single crystals, and sucks the inert gas, evaporant, and dust from the exhaust pipe 38 and supplies them to the scrubber 41 through the exhaust pipe 40. The scrubber 41 makes sludge of deposits passing through the exhaust pipe 40 and an exhaust pipe 45 described later.

One end of the exhaust pipe 36 is connected to an input end of a sub-valve 42 which is opened when the deposit is removed and closed when the silicon single crystal is produced. The output end of the sub-valve 42 is connected to the input end of the blower 44 via the exhaust pipe 43. An output end of the blower 44 is connected to one end of the exhaust pipe 45, and the other end of the exhaust pipe 45 is connected to the vicinity of the other end of the exhaust pipe 40. The blower 44 operates during the removal of the deposits, sucks the air, inert gas, dust, and deposits from the exhaust pipe 43, and supplies the sucked air, inert gas, dust, and deposits to the scrubber 41 through the exhaust pipe 45 and the exhaust pipe 40.

The piping portion 13 is a feature of embodiment 1, and an example of the structure thereof will be described with reference to fig. 3 to 5. Fig. 3 is a perspective view showing an example of a structure of the piping part 13 constituting the semiconductor crystal manufacturing apparatus 1 shown in fig. 2, fig. 4 is a plan view showing an example of a structure of the piping part 13, and fig. 5 is a side view showing an example of a structure of the piping part 13. The piping part 13 is composed of individual exhaust pipes 31A to 31D and a connecting pipe 32. The individual exhaust pipes 31A to 31D and the connecting pipe 32 are substantially cylindrical and have the same inner diameter.

The piping part 13 is configured to discharge gasThe port 24A is connected to the 2 nd joint C of the joint pipe 32 via the individual exhaust pipe 31A₂₁From the exhaust port 24B to the 2 nd joint C of the joint pipe 32 via the individual exhaust pipe 31B₂₁From the exhaust port 24C to the 2 nd joint C of the joint pipe 32 through the individual exhaust pipe 31C₂₁From the exhaust port 24D to the 2 nd joint C of the joint pipe 32 through the individual exhaust pipe 31D₂₁Are all equal.

In fig. 3 and 5, the individual exhaust pipe 31B includes a connection portion 61B, an upper portion 62B, and a lower portion 63B. The connection portion 61B has a flange and is connected to the exhaust port 24B (see fig. 2). The upper portion 62B has one end connected to the connecting portion 61B and extends vertically downward. One end of the lower portion 63B is connected to the other end of the upper portion 62B, extends from this portion to below the reference surface RT1, and the other end is connected to the vicinity of one end 71A of the branch portion 71 constituting the connecting pipe 32 and the other end of the lower portion 63C constituting the individual exhaust pipe 31C and is connected to the 1 st connecting portion C₁₁And (4) connecting.

In fig. 3 and 5, the individual exhaust pipe 31C includes a connecting portion 61C, an upper portion 62C, and a lower portion 63C. The connection portion 61C has a flange and is connected to the exhaust port 24C (see fig. 2). The upper portion 62C has one end connected to the connecting portion 61C and extends vertically downward. One end of the lower portion 63C is connected to the other end of the upper portion 62C, extends from this portion to below the reference surface RT1, and the other end is connected to the vicinity of one end 71A of the branch portion 71 constituting the connecting pipe 32 and the other end of the lower portion 63B constituting the individual exhaust pipe 31B and is connected to the 1 st connecting portion C₁₁And (4) connecting. As shown in fig. 5, the

individual exhaust pipes

31B and 31C are symmetrical with respect to the reference plane RT1, and are formed in a substantially V-shape with the reference plane RT1 as the center.

Fig. 3 shows a structure of a piping unit of the present invention in which 4 exhaust ports are connected to 4 individual exhaust pipes 31A to 31D, respectively. As shown in fig. 3, the individual exhaust pipe 31A includes a connection portion 61A, an upper portion 62A, and a lower portion 63A. The connection portion 61A has a flange and is connected to the exhaust port 24A (see fig. 2). Upper portion 62A has one end connected to connecting portion 61A and extends vertically. One end of the lower portion 63A is connected to the other end of the upper portion 62A, extends from this portion to below the reference surface RT1 (see fig. 4), and the other end is connected to the vicinity of one end 72A of the branch portion 72 constituting the coupling pipe 32 and constitutes the individual exhaust pipe 3The other end of the lower part 63D of the 1D is connected to the 1 st connecting part C₁₂And (4) connecting.

As shown in fig. 3, the individual exhaust pipe 31D includes a connecting portion 61D, an upper portion 62D, and a lower portion 63D. The connection portion 61D has a flange and is connected to the exhaust port 24D (see fig. 2). The upper portion 62D has one end connected to the connecting portion 61D and extends vertically downward. One end of the lower portion 63D is connected to the other end of the upper portion 62D, extends from this portion to below the reference surface RT1 (see fig. 4), and the other end is connected to the vicinity of one end 72A of the branch portion 72 constituting the connecting pipe 32 and the other end of the lower portion 63A constituting the individual exhaust pipe 31A and is connected to the 1 st connecting portion C₁₂And (4) connecting. The

individual exhaust pipes

31A and 31D are symmetrical with respect to the reference surface RT1, and are formed in a substantially V-shape with the reference surface RT1 as the center. The combination of the

individual exhaust pipes

31B and 31C and the combination of the

individual exhaust pipes

31A and 31D are symmetrical with respect to the reference surface RT2 (see fig. 4).

As shown in fig. 3 and 4, the coupling pipe 32 includes a branch portion 71, a branch portion 72, and a base portion 73. The branch portion 71 has one end 71A near which the other end of the lower portion 63B of the individual exhaust pipe 31B is joined to the other end of the lower portion 63C of the individual exhaust pipe 31C to form a 1 st joint portion C₁₁And (4) connecting. Branch portion 71 extends obliquely upward toward reference surface RT2 in fig. 4 while avoiding interference with drive mechanism 51, and the other end is coupled to the other end of branch portion 72 and one end of base portion 73 and to second coupling portion C₂₁And (4) connecting.

The branch portion 72 is connected to the 1 st connection portion C near the one end 72A by the other end of the lower portion 63A of the individual exhaust pipe 31A and the other end of the lower portion 63D of the individual exhaust pipe 31D₁₂And (4) connecting. Branch portion 72 extends obliquely downward toward reference surface RT2 in fig. 4 while avoiding interference with drive mechanism 51, and the other end thereof is coupled to the other end of branch portion 71 and one end of base portion 73 and to second coupling portion C₂₁And (4) connecting. The other end of the base 73, i.e., the end of the joint pipe 32, is connected to the input end of the return bend 33 (see fig. 2). Branch portion 71 and branch portion 72 are symmetrical with respect to reference surface RT 2. As shown in fig. 4, the coupling pipe 32 is substantially Y-shaped about a reference surface RT 2. Further, the 2 nd joining part C₂₁As shown in fig. 4, lies on a plane orthogonal to reference plane RT 2.

As described above, in embodiment 1, the piping section 13 formed by the individual exhaust pipes 31A to 31D and the coupling pipe 32 is formed in a shape in which the individual exhaust pipe 31B and the individual exhaust pipe 31C are symmetrical with respect to the reference surface RT1, and the individual exhaust pipe 31A and the individual exhaust pipe 31D are symmetrical with respect to the reference surface RT 1. The combination of the

individual exhaust pipes

31B and 31C and the combination of the

individual exhaust pipes

31A and 31D are symmetrical with respect to the reference surface RT 2. Further, the coupling pipe 32 has a symmetrical shape with respect to the reference surface RT 2.

Therefore, the pipe portion 13 is a 2 nd joint portion C from the exhaust port 24A to the joint pipe 32 via the individual exhaust pipe 31A₂₁From the exhaust port 24B to the 2 nd joint C of the joint pipe 32 via the individual exhaust pipe 31B₂₁From the exhaust port 24C to the 2 nd joint C of the joint pipe 32 through the individual exhaust pipe 31C₂₁From the exhaust port 24D to the 2 nd joint C of the joint pipe 32 through the individual exhaust pipe 31D₂₁Are all equal. The individual exhaust pipes 31A to 31D and the connecting pipe 32 are substantially cylindrical and have the same inner diameter.

Therefore, when the main pump 39 is operated during the production of silicon single crystal, the exhaust rates in the respective exhaust pipes 31A to 31D are substantially the same. As a result, for example, the joint C of the joint pipe 32₂₁In the above-described methods, the flow of the inert gas is hardly disturbed, and therefore the problems (1) to (3) are less likely to occur than in the conventional method described in document 1.

In embodiment 1, the

individual exhaust pipes

31B and 31C are combined, the

individual exhaust pipes

31A and 31D are combined, and then the respective combinations are connected to the connecting pipe 32. Therefore, the exhaust velocities in the respective exhaust pipes 31A to 31D can be configured to be equal in the shortest distance while avoiding interference with the drive mechanism 51. Further, the individual exhaust pipes 31A to 31D and the connecting pipe 32 are symmetrical in shape, and therefore, they are easy to manufacture.

Embodiment 2.

In embodiment 1, the exhaust ports 24A to 24D are formed on the substrate (not shown) placed on the floor surface FC, respectively, by constituting the bottom of the cavity 21 shown in fig. 2. The present invention can be applied to, for example, the semiconductor crystal manufacturing apparatus 2 shown in fig. 6 and 7. Fig. 6 is a conceptual diagram showing an example of the structure of a semiconductor crystal manufacturing apparatus 2 according to embodiment 2 of the present invention, and fig. 7 is a cross-sectional view showing an example of the structure of an exhaust passage of the semiconductor crystal manufacturing apparatus 2. In fig. 6 and 7, the same reference numerals are given to portions corresponding to those in fig. 2, and the description thereof will be omitted.

The semiconductor crystal manufacturing apparatus 2 is, for example, an appropriate apparatus used when an n-type dopant is added to a silicon melt. In the semiconductor crystal manufacturing apparatus 2, the heater 81 for heating the silicon melt M is disposed outside the crucible 25 composed of the graphite crucible 25A and the quartz crucible 25B with a predetermined interval therebetween, and the substantially cylindrical heat insulating cylinder 82 composed of a heat insulating material is disposed outside the heater 81 with a predetermined interval therebetween. An inner cylinder 83 having a substantially cylindrical shape is disposed between the heater 81 and the heat insulating cylinder 82. The inner cylinder 83 is made of a carbon member (e.g., graphite).

2 consisting of a long member having a substantially コ -shaped cross section on the outer periphery of the inner cylinder 83ⁿThe exhaust pipes 84 (n is an integer of 2 or more) are joined, and in embodiment 2, n is 2, that is, 4 exhaust pipes 84 are joined. The 4 exhaust ducts 84 are arranged at 4 positions on the outer periphery of the inner cylinder 83 so as to be adjacent to each other at an angle of substantially 90 ° around the central axis of the crucible 25. The exhaust conduits 84 are of the same shape and the same size.

The base plate 21A forming the bottom of the chamber 21 has 2 exhaust ducts 84 formed at positions corresponding to the 4 exhaust ducts 84, respectivelyⁿAnd an exhaust port 85, where n is 2 in embodiment 2. Namely 4 exhaust ports 85A-85D. The exhaust ports 85A to 85D are connected to the lower ends of the corresponding exhaust ducts 84, respectively, are introduced into the chamber 21, and discharge the inert gas passing through the exhaust ducts 84 to the outside. Fig. 6 shows only the

exhaust ports

85A and 85B.

As shown in fig. 6, an upper exhaust port 83A is formed above the upper end of the heater 81 and a lower exhaust port 83B is formed below the lower end of the heater 81 in 4 portions of the inner tube 83 to which the 4 exhaust ducts 84 are joined.

In the chamber 21, a heat retaining plate 86 extending inward is provided at an upper end portion of the heat retaining cylinder 82. A radiation shield 87 for preventing the excessive radiation heat from the heater 81 and the like from being applied to the silicon single crystal SM during growth is provided at the inner peripheral end of the heat-insulating plate 86.

The radiation shield 87 is formed so that the upper and lower portions are opened and a tapered surface is formed so that the area of the opening gradually decreases from the upper portion to the lower portion above the crucible 25 and around the silicon single crystal SM in the vicinity. By providing the radiation shield 87, the inert gas supplied into the crucible 25 from above flows through the gap between the radiation shield 87 and the silicon melt M, and is discharged to the outside of the crucible 25.

The 4 exhaust ports 85A to 85D are connected to a piping unit having the same structure as the piping unit 13 shown in fig. 3 to 5. However, since the exhaust duct 84 has a cross-sectional shape of approximately コ, for example, the cross-sectional shape of the exhaust ports 85A to 85D needs to be approximately rectangular, and the flanges of the connection portions 61A to 61D constituting the individual exhaust pipes 31A to 31D need to have shapes that can be closely connected to the exhaust ports 85A to 85D.

With this configuration, the same effects as those of embodiment 1 can be obtained. Furthermore, in embodiment 2, even if the adhered matter adhered to the vicinity of the upper exhaust port 83A of the inner cylinder 83 peels off due to the air flow flowing back in the exhaust duct 84, the adhered matter can be prevented from being mixed into the silicon melt M for some reason. Therefore, even when an n-type dopant is added to the silicon melt M, the concentration of the n-type dopant in the silicon melt M can be prevented from increasing, and desired properties (for example, resistivity) can be imparted to the silicon single crystal.

Examples

The semiconductor crystal manufacturing apparatus of the present invention is further explained based on the embodiment. In this example, experiments were actually performed using the semiconductor crystal manufacturing apparatus having the structure shown in embodiment mode 1, and the effects thereof were verified.

Comparative examples 1 to 3

The pipe sections used in comparative examples 1 to 3, which are compared with the examples, have substantially the same configurations as those of the pipe section 13 described in document 1, and the configurations shown in fig. 8 and 9 are employed instead of the pipe section 13 described in embodiment 1. The other structure is not changed from the structure shown in embodiment 1. Fig. 8 is a plan view showing an example of the structure of the pipe portion 91 as a comparative example, and fig. 9 is a side view showing an example of the structure of the pipe portion 91.

The piping part 91 is composed of 4 individual exhaust pipes 92A to 92D and a connecting pipe 93. The individual exhaust pipe 92B has a substantially cylindrical shape, has a flange at one end, is connected to the exhaust port 24B (see fig. 2), and extends vertically downward. The other end of the individual exhaust pipe 92B is connected to one end of a branch portion 94 constituting a coupling pipe 93.

The individual exhaust pipe 92C has a substantially cylindrical shape, has a flange at one end, is connected to the exhaust port 24C (see fig. 2), and extends vertically downward. The other end of the individual exhaust pipe 92C is connected to the vicinity of the other end of the branch portion 94 constituting the coupling pipe 93.

The individual exhaust pipe 92A has a substantially cylindrical shape, has a flange at one end, is connected to the exhaust port 24A (see fig. 2), and extends vertically downward. The other end of the individual exhaust pipe 92A is connected to one end of a branch portion 95 constituting the coupling pipe 93.

The individual exhaust pipe 92D has a substantially cylindrical shape, has a flange at one end, is connected to the exhaust port 24D (see fig. 2), and extends vertically downward. The other end of the individual exhaust pipe 92D is connected to the vicinity of the other end of the branch portion 95 constituting the coupling pipe 93.

The

branch portions

94 and 95 have a substantially cylindrical shape and extend in the horizontal direction. The other end of branch portion 94 and the other end of branch portion 95 are connected to both ends of beam portion 96A constituting base portion 96 having a substantially T-shape in plan view. One end of connection pillar portion 96B extends in the horizontal direction substantially at the center of beam portion 96A constituting base portion 96. The other end of the post portion 96B is connected to the input end of the return bend 33 shown in fig. 2. The individual exhaust pipes 92A to 92D and the connecting pipe 93 are substantially cylindrical and have the same inner diameter.

The semiconductor crystal manufacturing apparatus using the piping unit 13 of embodiment 1 is an example, and 3 semiconductor crystal manufacturing apparatuses using the piping unit 91 having the structure shown in fig. 8 and 9 are comparative examples 1 to 3. The measurement results of the exhaust air velocity are shown in table 1. In the embodiment shown in Table 1, 31A to 31C represent the individual exhaust pipes 31A to 31C shown in FIGS. 3 to 5. Similarly, in comparative examples 1 to 3 in Table 1, 92A to 92C represent the individual exhaust pipes 92A to 92C shown in FIG. 8 and FIG. 9.

In table 1, the reason why the value of the

individual exhaust pipes

31A and 31B and the

individual exhaust pipes

92A and 92B is 1.00 is that the ratio of the exhaust wind speed values of the

individual exhaust pipes

31D and 31C and the

individual exhaust pipes

92D and 92C combined with them is shown based on the exhaust wind speed values thereof.

Table 1 shows the standard deviation of the ratio of the measured values of the exhaust air speed of the individual exhaust pipes 31A to 31C of the example and the standard deviation of the ratio of the measured values of the exhaust air speed of the individual exhaust pipes 92A to 92C of the comparative examples 1 to 3. The standard deviation is one of the numerical values representing the unevenness of the data and the probability variables. Therefore, in the individual exhaust pipes constituting the semiconductor crystal manufacturing apparatus, the smaller the standard deviation, the more uniformly the inert gas and the like are discharged, and the larger the standard deviation, the more uniformly the inert gas and the like are discharged.

The inner diameters of the exhaust pipes at the measurement positions for measuring the exhaust air speeds are all the same in the individual exhaust pipes 31A to 31D and the individual exhaust pipes 92A to 92D. Therefore, the exhaust air velocity measurement value ratios shown in table 1 are synonymous with and interchangeable with the exhaust air volume ratios.

Table 1 shows that the exhaust air velocity values in all the individual exhaust pipes 31A to 31D in the examples are equal to each other, as compared with the exhaust air velocity values of the

individual exhaust pipes

92D and 92C in comparative examples 1 to 3, which are changed to about 30%. Therefore, according to the embodiment, the gas flow (wind speed) is smooth in each of the individual exhaust pipes 31A to 31D, and the probability (free rate) that defects do not occur in the silicon single crystal to be produced is increased.

[ Table 1]

。

As described above, in comparative examples 1 to 3 in table 1, the exhaust air velocity values of the

individual exhaust pipes

92D and 92C are about 30% higher than the exhaust air velocity values of the paired

individual exhaust pipes

92A and 92C. In the pair of

individual exhaust pipes

92A and 92D, the distance from each end to the other end of the base 96 is such that the individual exhaust pipe 92D is shorter than the individual exhaust pipe 92A. In the pair of

individual exhaust pipes

92B and 92C, the distance from each end to the other end of the base 96 is such that the individual exhaust pipe 92C is shorter than the individual exhaust pipe 92B. Thus, the exhaust air velocity value is substantially inversely proportional to the length of the exhaust pipe.

In table 1, the standard deviation of the exhaust air speed of the example is 0.02, while the standard deviation of the exhaust air speed of the comparative example 3 is 0.13. Thus, for example, considering the safety factor, if the standard deviation of the exhaust air speed is within ± 8%, it is considered that the disturbance of the airflow hardly occurs. As described above, the exhaust wind speed value is approximately inversely proportional to the length of the exhaust pipe. Therefore, if the length variation (standard deviation) of the exhaust pipe is within ± 8%, it is considered that the inert gas and the like are uniformly discharged, and the disturbance of the gas flow is difficult to occur. In the quantitative descriptions of "substantially equal" in the embodiments 1, 3 and 4, the variation of "distance" can be said to be within ± 8%.

While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to these embodiments, and modifications of the design and the like that do not depart from the scope of the present invention are also encompassed by the present invention.

For example, in the above embodiments, the semiconductor crystal is a silicon single crystal, but the invention is not limited thereto. The semiconductor crystal may be any of polycrystalline silicon, GAAs single crystal, GAAs polycrystalline silicon, InP single crystal, InP polycrystalline silicon, ZnS single crystal, ZnS polycrystalline silicon, ZnSe single crystal, and ZnSe polycrystalline silicon. In addition, in the above embodiments, the present invention is applied to the case of manufacturing a semiconductor crystal by using the CZ method, but the present invention is not limited thereto, and the present invention can be obviously applied to the case of manufacturing a semiconductor crystal by using the FZ method.

Claims

1. A semiconductor crystal manufacturing apparatus is characterized in that,

comprises 1 st, 2 nd, 3 rd and 4 th exhaust ports, 1 st, 2 nd, 3 rd and 4 th individual exhaust pipes, 1 st joint part, 2 nd joint part and joint pipe,

the 1 st, 2 nd, 3 rd and 4 th exhaust ports exhaust the gas introduced into the chamber for manufacturing the semiconductor crystal,

the 1 st, 2 nd, 3 rd and 4 th exhaust pipes are connected to the 1 st to 4 th exhaust ports at one end,

the 1 st joint is formed by joining and connecting the other ends of the 1 st and 2 nd exhaust pipes in adjacent pairs,

the 2 nd connecting portion is formed by connecting and connecting the other ends of the 3 rd and 4 th exhaust pipes adjacent to each other,

the connecting pipe has a 1 st branch portion having one end connected to the 1 st connecting portion, a 2 nd branch portion having one end connected to the 2 nd connecting portion, the other ends of the 1 st and 2 nd branch portions being connected to the 3 rd connecting portion,

the distances from the 1 st to 4 th exhaust ports to the 3 rd joint portion through the corresponding 1 st to 4 th individual exhaust pipes are substantially equal.

2. The semiconductor crystal manufacturing apparatus according to claim 1,

the 1 st to 4 th exhaust ports are provided at symmetrical positions with respect to a central axis of a drive mechanism for rotating and lifting the crucible provided in the chamber,

a pair of the 1 st and 2 nd individual exhaust pipes are symmetrical with respect to a 1 st reference plane passing through the center axis,

a pair of the 3 rd and 4 th exhaust pipes are symmetrical with respect to the 1 st reference surface,

the pair of 1 st and 2 nd individual exhaust pipes and the pair of 3 rd and 4 th individual exhaust pipes are provided at symmetrical positions with respect to a 2 nd reference plane that is different from the 1 st reference plane by the center axis.

3. The semiconductor crystal manufacturing apparatus according to claim 1 or 2,

a silicon single crystal to which an n-type dopant is added is produced.

4. A semiconductor crystal manufacturing apparatus is characterized in that,

is provided with 2ⁿAn exhaust port, 2ⁿIndividual exhaust pipes, 2^n-11 st binding part, 2^n-k-1(k + 1) th joint part, 2^n-k-1A kth joint pipe, wherein n is an integer of 2 or more, and k is a positive integer increasing one by one from 1 to (n-1),

the foregoing 2ⁿThe exhaust port exhausts gas introduced into the chamber for manufacturing the semiconductor crystal,

the foregoing 2ⁿEach end of each exhaust pipe is connected to each corresponding exhaust port,

the foregoing 2^n-1The 1 st joint is formed by joining and connecting the other ends of the adjacent pair of the individual exhaust pipes,

the foregoing 2^n-k-1The kth joint pipe has a pair of branch portions, each of one ends of the branch portions is connected to each of the adjacent pair of kth joint portions, and each of the other ends of the branch portions is connected to the corresponding (k + 1) th joint portion by being joined,

the distances from each exhaust port to the n-th joint through the corresponding individual exhaust pipes are substantially equal.

5. The semiconductor crystal manufacturing apparatus according to claim 4,

the foregoing 2ⁿThe exhaust ports are arranged at symmetrical positions relative to the central axis of a driving mechanism which rotates and lifts the crucible arranged in the cavity,

two adjacent individual exhaust pipes are symmetrical with respect to a reference plane passing through the center axis, and the other two adjacent individual exhaust pipes are provided at symmetrical positions with respect to a reference plane passing through the center axis and different from the reference plane.

6. The semiconductor crystal manufacturing apparatus according to claim 4 or 5,

a silicon single crystal to which an n-type dopant is added is produced.

7. A semiconductor crystal manufacturing apparatus is characterized in that,

comprises a cavity, a crucible, a heater, and a heater 2ⁿRoot exhaust pipe, 2ⁿAn exhaust port, 2ⁿIndividual exhaust pipes, 2^n-11 st binding part, 2^n-k-1(k + 1) th joint part, 2^n-k-1A kth joint pipe, wherein n is an integer of 2 or more, and k is a positive integer increasing one by one from 1 to (n-1),

the aforementioned cavity produces a semiconductor crystal,

the crucible is arranged in the cavity,

the heater is disposed so as to surround the crucible and heat the crucible,

the foregoing 2ⁿAn exhaust duct formed at the upper exhaust port for exhausting the gas introduced into the chamber from the upper part of the heater and at the lower part of the corresponding upper exhaust port, and communicating with each of the lower exhaust ports for exhausting the gas from the lower part of the heater,

the foregoing 2ⁿThe exhaust ports are formed at the bottom of the cavity and connected with the lower ends of the corresponding exhaust ducts,

the foregoing 2ⁿEach end of each individual exhaust pipe is connected to each corresponding exhaust port,

the distances from the upper end of each exhaust pipe to the nth connection portion through the corresponding individual exhaust pipe are substantially equal.

8. The semiconductor crystal manufacturing apparatus according to claim 4,

9. The semiconductor crystal manufacturing apparatus according to claim 7 or 8,

a silicon single crystal to which an n-type dopant is added is produced.

10. A piping structure of a semiconductor crystal manufacturing apparatus is characterized in that,

11. The piping structure of a semiconductor crystal manufacturing apparatus according to claim 10,

12. A piping structure of a semiconductor crystal manufacturing apparatus is characterized in that,

includes the 1 st, 2 nd, 3 rd, 4 th, 5 th, 6 th, 7 th and 8 th exhaust ports, the 1 st, 2 nd, 3 rd, 4 th, 5 th, 6 th, 7 th and 8 th individual exhaust pipes, the 1 st joint part, the 2 nd joint part, the 3 rd joint part, the 4 th joint part, the 1 st joint pipe, the 2 nd joint pipe and the 3 rd joint pipe,

the above-mentioned 1 st, 2 nd, 3 rd, 4 th, 5 th, 6 th, 7 th and 8 th exhaust ports exhaust the gas introduced into the chamber for manufacturing the semiconductor crystal,

the 1 st, 2 nd, 3 rd, 4 th, 5 th, 6 th, 7 th and 8 th exhaust pipes are connected to the 1 st to 8 th exhaust ports at one end,

the 3 rd joint is formed by joining and connecting the other ends of the 5 th and 6 th exhaust pipes in adjacent pairs,

the 4 th joint is formed by joining and connecting the other ends of the 7 th and 8 th exhaust pipes in adjacent pairs,

the 1 st connecting pipe has a 1 st branch portion having one end connected to the 1 st connecting portion, a 2 nd branch portion having one end connected to the 2 nd connecting portion, the other ends of the 1 st and 2 nd branch portions being connected to a 5 th connecting portion,

the 2 nd connecting pipe has a 3 rd branch portion having one end connected to the 3 rd connecting portion and a 4 th branch portion having one end connected to the 4 th connecting portion, and the other ends of the 3 rd and 4 th branch portions are connected to a 6 th connecting portion,

the 3 rd connecting pipe has a 5 th branch portion having one end connected to the 5 th joint portion and a 6 th branch portion having one end connected to the 6 th joint portion, the other ends of the 5 th and 6 th branch portions are connected to a 7 th joint portion,

distances from the 1 st to 8 th exhaust ports to the 7 th joint portion through the corresponding 1 st to 8 th individual exhaust pipes are substantially equal.

13. The piping structure of a semiconductor crystal manufacturing apparatus according to claim 12,

the 1 st to 8 th exhaust ports are provided at symmetrical positions with respect to a central axis of a drive mechanism for rotating and lifting the crucible provided in the chamber,

the pair of 1 st and 2 nd individual exhaust pipes are symmetrical with respect to a 1 st reference plane passing through the center axis, the 1 st joint part and the 3 rd joint part,

a pair of the 3 rd and the 4 th individual exhaust pipes are symmetrical with respect to a 2 nd reference plane passing through the center axis, the 2 nd joint part and the 4 th joint part and orthogonal to the 1 st reference plane,

a pair of 5 th and 6 th exhaust pipes having symmetrical shapes with respect to the 1 st reference surface,

a pair of 7 th and 8 th exhaust pipes having symmetrical shapes with respect to the 2 nd reference plane,

the 1 st joint pipe is symmetrical with respect to a 3 rd reference plane which passes through the center axis, the 5 th joint part and the 6 th joint part and is a symmetrical plane of the 1 st reference plane and the 2 nd reference plane,

the 2 nd coupling pipe has a symmetrical shape with respect to the 3 rd reference surface,

the 3 rd coupling pipe is symmetrical with respect to a 4 th reference plane passing through the center axis and the 7 th coupling part and perpendicular to the 3 rd reference plane,

a pair of the 1 st and 2 nd individual exhaust pipes and a pair of the 3 rd and 4 th individual exhaust pipes are provided at symmetrical positions with respect to the 3 rd reference surface,

a pair of the 5 th and 6 th individual exhaust pipes and a pair of the 7 th and 8 th individual exhaust pipes are provided at symmetrical positions with respect to the 3 rd reference surface,

the 1 st to 4 th exhaust pipes and the 5 th to 8 th exhaust pipes are disposed at symmetrical positions with respect to the 4 th reference surface.

14. A piping structure of a semiconductor crystal manufacturing apparatus is characterized in that,

the foregoing 2ⁿOne end of each exhaust conduit is connected with each corresponding exhaust port,

the foregoing 2^n-1The 1 st joint is formed by joining and connecting the other ends of a pair of the individual exhaust pipes adjacent to each other,

the foregoing 2^n-k-1The kth joint pipe has a pair of branch parts, each end of the branch parts is connected to the adjacent pair of kth joint parts, and the branch partsThe other ends of the branch parts are connected with the corresponding (k + 1) th connecting parts,