JP4597432B2 - Vertical heat treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vertical heat treatment apparatus.
[0002]
[Prior art]
In the manufacture of semiconductor devices, various types of heat treatment apparatuses are used to perform processes such as oxidation, diffusion, and CVD (Chemical Vapor Deposition) on an object to be processed such as a semiconductor wafer. As one of them, there is known a vertical heat treatment apparatus capable of heat treating a large number of objects to be processed at one time.
[0003]
This vertical heat treatment apparatus has a vertical processing container for accommodating a large number of objects to be processed, and a heater having a cylindrical heat insulating material is installed around the processing container. As shown in FIG. 5, the outer periphery of the cylindrical heat insulating material 11 is covered with a metal outer shell (outer shell) 30, and a top heat insulating material (top block) 13 is provided on the upper portion of the cylindrical heat insulating material 11. An upper portion of the top heat insulating material 13 is covered with a metal top plate 31 connected to the outer skin 30. Reference numeral 35 denotes a blanket-like heat insulating material (blanket) placed on the top heat insulating material 13.
[0004]
[Problems to be solved by the invention]
However, in the conventional vertical heat treatment apparatus described above, when the heater is heated to a high temperature, for example, about 1000 ° C., the top plate 31 is thermally expanded as the temperature rises, and the central portion (center) and peripheral edge of the top plate 31 are expanded. Warpage deformation occurs due to temperature difference or thermal expansion difference from the part (edge). In a type in which a soft and thick futon-like heat insulating material 41 is placed on the top plate 31 in order to suppress the temperature rise at the top of the apparatus outer wall (housing) 40, the temperature difference is larger and deformation is also caused. There is a tendency to grow.
[0005]
In particular, when the top plate 31 is deformed downward, the top heat insulating material 13 is pressed as indicated by an arrow F, and the top heat insulating material 13 may be cracked or broken. If the top heat insulating material 13 is cracked or broken, heat escapes from the portion and the heater temperature becomes unstable, which may adversely affect the process.
[0006]
The present invention has been made in view of the above circumstances, and provides a vertical heat treatment apparatus capable of preventing cracking or breakage of the top heat insulating material of the heater by suppressing or preventing warping deformation downward of the top plate. The purpose is to do.
[0007]
[Means for Solving the Problems]
Among the present inventions, the invention according to claim 1 is characterized in that a heater having a cylindrical heat insulating material is installed around a vertical processing container accommodating a large number of objects to be processed, and the outer periphery of the cylindrical heat insulating material is arranged. In a vertical heat treatment apparatus, which is covered with an outer cover, provided with a top heat insulating material on the upper part of the tubular heat insulating material, and covered with an upper plate connected to the outer cover, the top plate is a plurality of concentric circles. The outer diameter of the small-diameter side divided piece is formed larger than the inner diameter of the large-diameter side divided piece, and the small-diameter side divided pieces are sequentially stacked on the large-diameter side divided piece. Ri Na mounted Te, characterized that you have been held in a state where the periphery of the respective segments can be tolerated by the heat deformation movement in the radial direction.
[0008]
According to a second aspect of the present invention, a heater having a cylindrical heat insulating material is installed around a vertical processing container that accommodates a large number of objects to be processed, and the outer periphery of the cylindrical heat insulating material is covered with an outer skin. In the vertical heat treatment apparatus in which a top heat insulating material is provided on the top of the cylindrical heat insulating material and the top of the top heat insulating material is covered with a top plate connected to the outer skin, the top plate has a convex portion with a central portion higher than the peripheral portion. Jo is molded in, characterized in that the periphery of the top plate is held in a state of acceptable thermal deformation movement in the radial direction.
[0009]
In order to hold the top plate or the split piece with screws, screw holes are provided at predetermined pitch intervals, and these screw holes are long holes in the radial direction of the top plate or long in the radial direction and radial direction. It is preferable that the outer side is formed as a notched part opened .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of a vertical heat treatment apparatus showing an embodiment of the present invention, and FIG. 2 is a plan view of a top plate portion.
[0011]
In FIG. 1, reference numeral 1 denotes a vertical heat treatment apparatus. The vertical heat treatment apparatus 1 accommodates a large number of objects to be processed such as semiconductor wafers w and performs a predetermined heat treatment such as a CVD process (process tube). 2 is provided. The processing container 2 is formed of a material having heat resistance and corrosion resistance, for example, quartz glass.
[0012]
In the illustrated example, the processing container 2 has a double tube structure of an inner tube 2a and an outer tube 2b. The inner tube 2a is open at the upper and lower ends. The outer tube 2b has an upper end closed and a lower end opened. In addition, the processing container 2 may consist only of the outer tube 2b.
[0013]
In the illustrated example, a short cylindrical manifold having a gas introduction part 3 for introducing a processing gas or an inert gas into the processing container 2 and an exhaust part 4 for exhausting the inside of the processing container 2 are provided below the processing container 2. 5 is provided. The manifold 5 is formed of a material having heat resistance and corrosion resistance, for example, stainless steel.
[0014]
The gas introduction unit 3 is connected to a gas supply system pipe leading to a gas source. An exhaust system having a vacuum pump and a pressure control mechanism is connected to the exhaust unit 4 so that the inside of the processing container 2 can be controlled to a predetermined processing pressure. In a state controlled by this processing pressure, the processing gas introduced from the gas introduction unit 3 rises in the inner tube 2a of the processing container 2 and is subjected to a predetermined heat treatment of the wafer w, and then the inner tube 2a and the outer tube 2a. The annular passage between the pipe 2b is lowered and exhausted from the exhaust part 4.
[0015]
A flange portion 5 f is formed at the upper end of the manifold 5, and a lower end flange portion 2 f of the outer tube 2 b is placed on the upper surface of the upper end flange portion 5 f and is bonded and fixed by a flange presser 6. Between the upper end flange portion 5f of the manifold 5 and the lower end flange portion 2f of the outer tube 2b, for example, an O-ring 7 as a sealing means is interposed. An inner tube support portion 8 for supporting the inner tube 2 a is provided inside the manifold 5.
[0016]
The manifold 5 is attached to the lower part of the base plate 9, and the upper part of the base plate 9 surrounds the periphery of the processing vessel 2 and is a heater for heating the wafer w in the processing vessel 2 to a predetermined heat treatment temperature. 10 is installed. The heater 10 includes a cylindrical (cylindrical) heat insulating material 11 that surrounds the periphery of the processing container 2, and resistance heating wires 12 are arranged in a spiral or meandering manner on the inner periphery of the cylindrical heat insulating material 11. ing. The heater 10 is configured to be capable of temperature control by being divided into a plurality of regions in the height direction.
[0017]
A disc-shaped top heat insulating material 13 which is a top heat insulating material of the heater 10 is covered (mounted) on the upper portion of the tubular heat insulating material 11 of the heater 10. The cylindrical heat insulating material 11 of the heater 10 main body and the top heat insulating material 13 at the top of the heater 10 are formed of a predetermined heat insulating material, for example, a mixed material of silica (SiO ₂ ) and alumina (Al ₂ O ₃ ).
[0018]
The outer periphery of the cylindrical heat insulating material 11 of the heater 10 is covered with a metallic outer shell (outer shell) 30 made of metal, for example, SUS, and the outer periphery of the outer shell 30 includes a water-cooled tube and a metal cover. A water cooling jacket is provided (not shown).
[0019]
The top of the top heat insulating material 13 of the heater 10 is covered with a top plate 31 made of, for example, SUS connected to the outer skin 30. In order to attach the top plate 31 to the upper end portion of the outer skin 30, a short cylindrical attachment member (top ring) 32 having an inverted L-shaped cross section having an inward flange 32 a at the upper end is attached to the inner periphery of the upper end portion of the outer skin 30. The top plate 31 is fixed to the inward flange 32a of the mounting member 32 by a fixing tool such as a screw 34.
[0020]
A gap s is provided between the top plate 31 and the top heat insulating material 13, and a cotton-like heat insulating material 35 is provided in the gap s. In order to prevent downward warping deformation due to a temperature difference or a thermal expansion difference between the central portion and the peripheral portion of the top plate 31, the top plate 31 has a plurality of, for example, three concentric circles as shown in FIG. It consists of divided pieces 31a, 31b, 31c, and the outer diameter of the small-diameter side divided piece is larger than the inner diameter of the large-diameter side divided piece among the adjacent divided pieces, and the small-diameter side divided on the large-diameter side divided piece The pieces are arranged one on top of the other.
[0021]
That is, the three divided pieces 31a, 31b, 31c, which are the center, middle, and peripheral edge, place the outer peripheral edge of the peripheral divided piece 31c on the inward flange 32a of the mounting member 32, and on the inner peripheral edge of the peripheral divided piece 31c. The outer peripheral edge of the intermediate divided piece 31b is placed, and the outer peripheral edge of the central divided piece 31a is placed on the inner peripheral edge of the intermediate divided piece 31b. As described above, the peripheral edge portion of the peripheral split piece 31c is fixed on the inward flange 32a of the mounting member 32 with the screw 34, and the peripheral edge portion of the intermediate split piece 31b is fixed on the peripheral split piece 31c with the screw 34 so as to be divided into the center part. The peripheral edge of the piece 31a is fixed on the intermediate divided piece 31b with screws 34.
[0022]
In this case, it is preferable that the peripheral portions of the divided pieces 31a, 31b, and 31c of the top plate 31 are held in a state that allows the thermal deformation movement in the radial direction. Specifically, screw holes (fixing tool small holes) 36 are provided at predetermined pitch intervals on the peripheral edge of each of the divided pieces 31a, 31b, and 31c. These screw holes 36 are long in the radial direction. It is formed as a hole (blemish hole) or a notch portion that is long in the radial direction and opened radially outward. Further, it is preferable that the screw 34 is loosely tightened so as to facilitate the thermal deformation movement in the radial direction of each of the divided pieces 31a, 31b, 31c. In addition, although the hole 37 is provided in the center part of the center division | segmentation piece 13a, this hole 37 does not necessarily need to be provided.
[0023]
In order to mount and hold a large number of, for example, about 150 semiconductor wafers w in the height direction at predetermined intervals in the processing container 2, the wafers w are held by a boat 15 made of, for example, quartz glass, which is a holding tool. Is placed on the upper portion of a lid 16 made of, for example, stainless steel, which seals the lower end opening (furnace port) of the manifold 5 via a heat retaining cylinder 17 serving as a furnace port heat insulating means. Below the processing container 2 is provided an elevating mechanism 18 for raising and lowering the lid body 16 to open and close the lid body 16 and for loading and unloading the boat 15 with respect to the processing container 2. An area 19 is provided.
[0024]
For example, an O-ring (not shown) as a sealing means is provided at a joint portion between the lower end (open end) of the manifold 5 and the lid body 16. In addition, the lid 16 is provided with a rotation mechanism 20 for rotating the boat 15 in order to enable in-plane uniform heat treatment of the wafer w.
[0025]
On the lower surface of the top heat insulating material 13, a heat resistant sheet such as an alumina cloth (for example, alumina cloth (in order to suppress or prevent the powdery dust (particles) falling or scattering when the top heat insulating material 13 is cracked or damaged) is formed. (Not shown) is preferably affixed, but the alumina cloth is not necessarily affixed.
[0026]
Next, the operation of the vertical heat treatment apparatus having the above configuration will be described. First, the boat 15 on which the transfer of the wafer w has been completed is placed on the heat retaining cylinder 17 on the lid 16 in the loading area 19. Next, the boat 15 is carried into the processing container 2 from its lower end opening (lower end opening portion of the manifold 5) by ascending the lid body 16 by the elevating mechanism 18, and the opening is airtightly closed by the lid body 16. Then, the inside of the processing container 2 is controlled to a predetermined pressure or degree of vacuum by decompression exhaust from the exhaust unit 4 by the exhaust system, the heater 10 is heated, and the gas introduction unit 3 is rotated while the boat 15 is rotated by the rotating mechanism 20. Then, a processing gas is introduced into the processing container 2 and a predetermined heat treatment such as a CVD process is started on the wafer w.
[0027]
When the predetermined heat treatment is completed, first, the heater 10 is cooled, the introduction of the processing gas is stopped, and the inside of the processing container 2 is purged by introducing the inert gas. Next, the rotation mechanism 20 is stopped, the lid 16 is lowered, the inside of the processing container 2 is opened, and the boat 2 may be carried out to the loading area 37.
[0028]
When the heater 10 is heated to a high temperature, for example, about 1000 ° C., the top of the heater 10 is insulated by the top heat insulating material 13 but cannot be completely insulated. A temperature difference is generated between the center portion (center) and the peripheral portion (edge) of 31. However, according to the vertical heat treatment apparatus 1, the top plate 31 is composed of the divided pieces 31a, 31b, 31c divided into a plurality of concentric circles, and the outer diameter of the small-diameter side divided piece among the adjacent divided pieces is large. Since it is formed larger than the inner diameter of the side split pieces and the small diameter side split pieces are sequentially stacked on the large diameter side split pieces, each of the split pieces 31a, 31b, 31c has a central side or an inner peripheral side and a peripheral side. Or the temperature difference between the outer peripheral side is reduced, the amount of thermal deformation of each of the divided pieces 31a, 31b, 31c is reduced, and the amount of thermal deformation of the entire top plate 31 can be reduced.
[0029]
Therefore, even if a futon-like heat insulating material (see FIG. 5) is placed on the top plate 31, warping deformation downward of the top plate 31 can be suppressed or prevented. It is possible to prevent cracks and breakage of the top heat insulating material 13 of the heater 10 due to warpage deformation. In particular, since each of the divided pieces 31a, 31b, 31c is held in a state in which the peripheral portion can permit the thermal deformation movement in the radial direction, the warping deformation of the top plate 31 downward is further sufficiently suppressed or prevented. Thus, cracks and breakage of the top heat insulating material 13 of the heater 10 can be further sufficiently prevented, and the durability of the top heat insulating material 13 can be improved and the stability and reliability of the process can be improved.
[0030]
3 and 4 show different modifications of the top plate portion. In these drawings, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted, and different parts will be described. The top plate 31 shown in FIGS. 3 to 4 is formed into a convex shape with the central portion 31x higher than the peripheral portion 31y, for example, by press molding. Specifically, the top plate 31 shown in FIG. 3 is formed in a so-called cross-sectional hat shape in which the central portion 31x protrudes upward from the peripheral portion 31y in a flat state. The top plate 31 is strong in strength because the boundary between the central portion 31x and the peripheral portion 31y is formed in an annular rib shape (that is, it has an annular rib 31z in the middle). In addition, the deformation direction of the top plate 31 can be restricted upward.
[0031]
The top plate 31 shown in FIG. 4 is formed in a curved shape that swells upward, and the deformation direction of the top plate 31 can be restricted upward. In any top plate 31 of FIG. 3 and FIG. 4, since the center portion 31 x is formed in a convex shape higher than the peripheral portion 31 y, even if a heat insulating material pad is placed on the top plate 31. Further, it is possible to prevent warping deformation of the top plate 31 downward, and to prevent cracking or breakage of the top heat insulating material 13 of the heater 10 caused by warping deformation of the top plate 31 downward. 13 can be improved in durability and process stability or reliability. In any top plate 31, the peripheral portion is held in a state in which the thermal deformation movement in the radial direction can be allowed, so that warping deformation of the top plate 31 downward can be further sufficiently suppressed or prevented. It is possible to sufficiently prevent cracking and breakage of the top heat insulating material 13 of the heater 10.
[0032]
Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above-described embodiments, and various design changes and the like can be made without departing from the scope of the present invention. is there. For example, in the above embodiment, the CVD process is exemplified as an example of the heat treatment, but the vertical heat treatment apparatus of the present invention can perform, for example, a diffusion process, an oxidation process, an annealing process, etc. in addition to the CVD process. It is. Moreover, in the said embodiment, although the vertical heat processing apparatus provided with the manifold in the processing container was illustrated, the vertical heat processing apparatus of this invention does not need to be provided with the manifold in the processing container. In addition to the semiconductor wafer, the object to be processed may be, for example, an LCD substrate or a glass substrate.
[0033]
【The invention's effect】
In short, according to the present invention, the following effects can be obtained.
[0034]
(1) According to the invention of claim 1 , a heater having a cylindrical heat insulating material is installed around a vertical processing container that accommodates a large number of objects to be processed, and the outer periphery of the cylindrical heat insulating material is provided. In a vertical heat treatment apparatus, which is covered with an outer cover, provided with a top heat insulating material on the upper part of the tubular heat insulating material, and covered with an upper plate connected to the outer cover, the top plate is a plurality of concentric circles. The outer diameter of the small-diameter side divided piece is formed larger than the inner diameter of the large-diameter side divided piece, and the small-diameter side divided pieces are sequentially stacked on the large-diameter side divided piece. Te Ri Na mounted, because is held in a state where the periphery of the respective segments can be tolerated by the heat deformation movement in the radial direction, it is possible to suppress or prevent warping deformation of the lower ceiling plate, the heater Cracks and breakage of the top heat insulating material can be prevented.
[0035]
(2) According to the invention of claim 2 , a heater having a cylindrical heat insulating material is installed around a vertical processing container that accommodates a large number of objects to be processed, and the outer periphery of the cylindrical heat insulating material is disposed. In the vertical heat treatment apparatus, which is covered with an outer cover, provided with a top heat insulating material on the upper part of the tubular heat insulating material, and covered with an upper plate connected to the outer cover, the top plate has a peripheral edge at the center. Since the peripheral part of the top plate is held in a state that allows the thermal deformation movement in the radial direction, the downward deformation of the top plate is suppressed or prevented. It is possible to prevent cracking and breakage of the top heat insulating material of the heater.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a vertical heat treatment apparatus showing an embodiment of the present invention.
FIG. 2 is a plan view of a top plate portion.
FIGS. 3A and 3B are diagrams showing a modification of the top plate portion, where FIG. 3A is a plan view and FIG. 3B is a cross-sectional view.
4A and 4B are diagrams showing a modification of the top plate portion, where FIG. 4A is a plan view and FIG. 4B is a cross-sectional view.
FIG. 5 is a cross-sectional view of a top plate portion in a conventional vertical heat treatment apparatus.
[Explanation of symbols]
w Semiconductor wafer (object to be processed)
DESCRIPTION OF SYMBOLS 1 Vertical heat processing apparatus 2 Processing container 10 Heater 11 Cylindrical heat insulating material 13 Top heat insulating material 30 Outer skin 31 Top plate 31a, 31b, 31c Divided piece 31x Center part 31y Top plate peripheral part

Claims (3)

A heater having a cylindrical heat insulating material is installed around a vertical processing container that accommodates a large number of objects to be processed, the outer periphery of the cylindrical heat insulating material is covered with an outer skin, and the top heat insulation is formed on the upper portion of the cylindrical heat insulating material. In the vertical heat treatment apparatus in which the top plate is covered with a top plate connected to the outer skin, the top plate is composed of a plurality of pieces that are concentrically divided into a plurality of adjacent pieces. the outer diameter of the inner diameter side split pieces is formed larger than the inner diameter of the large diameter side split pieces, Ri Na mounted one on top of the small diameter side split piece on the large diameter side split pieces, the periphery of respective segments vertical heat treatment apparatus which is characterized that you have been held with acceptable thermal deformation movement in the radial direction. A heater having a cylindrical heat insulating material is installed around a vertical processing container that accommodates a large number of objects to be processed, the outer periphery of the cylindrical heat insulating material is covered with an outer skin, and the top heat insulation is formed on the upper portion of the cylindrical heat insulating material. In the vertical heat treatment apparatus in which the top plate is covered with a top plate connected to the outer skin, the top plate is formed in a convex shape with a central portion higher than the peripheral portion , A vertical heat treatment apparatus characterized in that the peripheral edge of the top plate is held in a state that allows thermal deformation movement in the radial direction . In order to hold the top plate or the split piece with screws, screw holes are provided at predetermined pitch intervals, and these screw holes are long holes in the radial direction of the top plate or long in the radial direction and radial direction. The vertical heat treatment apparatus according to claim 1, wherein the vertical heat treatment apparatus is formed as a notched portion having an open outer side .

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