JP2004039967A - Semiconductor production apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a reduction in temperatures in a power supply part as a non-heat-generation part by decreasing an interval between both the power supply parts, and to restrict influences on a temperature distribution by shifting the power supply to a circumferential direction. <P>SOLUTION: A heat unit is provided with a heat insulating block 26 formed in a cylindrical shape by using a heat insulating material and a heat generator 32 having a pair of power supplies 35, 36. In the heat unit, the heat generator is laid on an inner circumferential face of an attachment groove 30 of a heat insulating block 26. Both the power supplies 35, 36 are inserted into holding grooves 43, 44 of a holder 42 having a heat resistance and held in an insulating state, and a plus-side connection part 37 of the heat generator 32 on a lower stepped side is located just under a minus-side connection part 38 of the heat generator 32 on an upper stepped side to be slid to a circumferential direction. A crossover 46 in a round rod shape is welded between the minus-side connection part 38 of the heat generator 32 on the upper stepped side and the plus-side connection part 37 of the heat generator 32 on the lower stepped side. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor manufacturing apparatus, and more particularly to an improvement of a heater unit for heating a substrate, for example, nitriding a semiconductor wafer (hereinafter, referred to as a wafer) in which a semiconductor integrated circuit device (hereinafter, referred to as an IC) is formed. Low-pressure CVD apparatus for depositing (deposition) silicon (Si ₃ N ₄ ), polysilicon, etc., oxide film forming apparatus and diffusion apparatus, heat treatment such as reflow and annealing for carrier activation and planarization after ion implantation. The present invention relates to a heat treatment apparatus (furnace) used for (thermal treatment) or the like, which is effective when used in a semiconductor manufacturing apparatus.
[0002]
[Prior art]
2. Description of the Related Art In a method of manufacturing an IC, a batch type vertical hot wall type reduced pressure CVD apparatus is widely used to deposit a CVD film such as silicon nitride or polysilicon on a wafer. A batch-type vertical hot-wall-type reduced-pressure CVD apparatus (hereinafter, referred to as a CVD apparatus) is a vertically installed process tube that includes an inner tube that forms a processing chamber into which a wafer is loaded, and an outer tube that surrounds the inner tube. A boat that holds a plurality of wafers as substrates to be processed and carries the wafer into the processing chamber of the inner tube, a gas introduction pipe that introduces a source gas into the inner tube, and an exhaust pipe that exhausts the inside of the process tube, A heater unit laid outside the process tube to heat the inside of the process tube, and a plurality of wafers are loaded into the inner tube from the furnace port at the lower end while being aligned and held vertically by the boat ( Boat loading) and the raw material gas is introduced into the inner tube from the gas inlet pipe. By the process tube is heated by the heater unit, CVD film is configured to be deposited on the wafer.
[0003]
In a conventional CVD apparatus of this type, a heat insulating unit such as alumina or silica is used as a heater unit, and a heat insulating wall formed into a long cylindrical shape that entirely covers a process tube by a vacuum foam (vacuum suction molding) method. A heating element formed by using an iron-chromium-aluminum (Fe-Cr-Al) alloy or molybdenum silicide (MoSi ₂ ), and a case for covering a heat insulating wall. Is laid on the inner periphery of the heat insulating wall.
[0004]
When performing rapid heating at 30 ° C./min or more in such a heater unit, a heating element formed in a plate shape is used to increase the effective heating area. When this plate-shaped heating element is used, a power supply section for supplying electricity to the heating element is configured as follows. The plate-shaped heating element is bent at a right angle in the thickness direction and penetrates the heat insulating wall, and the penetrating portion is further bent at a right angle, and the power supply terminal is connected to the bent portion. A separate heating element is also welded to the bent portion of the power supply section to reinforce the power supply section in order to prevent the ramp from being caused by thermal expansion during heat generation. In addition, a separate heating element having the same plate shape as the heating element is used as a crossover connecting the upper and lower heating elements at the outer bent portion. Similarly, a separate heating element having a plate shape is used as the power supply terminal, and is drawn out of the case.
[0005]
[Problems to be solved by the invention]
However, since there is no heating element between the bent portions of the heating elements, the heating temperature is reduced, so that the temperature distribution in the wafer surface decreases toward the bent portion. Since the deviation of the temperature distribution in the wafer surface directly affects the film formation result, the film formation speed on the bent portion side becomes slow, and the film thickness distribution is seriously affected.
[0006]
An object of the present invention is to provide a semiconductor manufacturing apparatus capable of preventing a temperature drop in a power supply unit without a heating element.
[0007]
[Means for Solving the Problems]
A first means for solving the problem is that a heating element having a pair of power supply portions is laid on an inner periphery of a heat insulating wall formed in a cylindrical shape, and the pair of power supply portions is a heat-resistant holder. Are held in a state of being insulated from each other.
[0008]
According to the above-described first means, the pair of power supply units held by the holder can be brought close to each other, so that a temperature drop in the power supply unit without a heating element can be suppressed to a minimum.
[0009]
A second means for solving the problem is that a plurality of heating elements having a pair of power supply portions are arranged in the same direction as the cylinder core on the inner periphery of a heat-insulating wall formed in a cylindrical shape. It is characterized in that the pair of power supply portions of the heating element are shifted in the circumferential direction.
[0010]
According to the above-described second means, since the power supply units without the heating elements are not arranged in a line, it is possible to disperse the portion where the temperature decreases, and to suppress the influence on the heating temperature distribution of the plurality of heating elements. Can be.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0012]
As shown in FIG. 1, a CVD apparatus (batch type vertical hot wall type reduced pressure CVD apparatus) which is an embodiment of a semiconductor manufacturing apparatus according to the present invention is disposed vertically and fixedly supported. A vertical process tube 1 is provided. The process tube 1 includes an inner tube 2 and an outer tube 3. The inner tube 2 is integrally formed into a cylindrical shape using quartz (SiO ₂ ) or silicon carbide (SiC), and the outer tube 3 is formed of quartz glass. Is used to integrally mold into a cylindrical shape. The inner tube 2 is formed in a cylindrical shape with both upper and lower ends open. The hollow portion of the inner tube 2 defines a processing chamber 4 into which a plurality of wafers held in a vertically aligned state by a boat 11 are loaded. Has formed. The lower end opening of the inner tube 2 constitutes a furnace port 5 for taking in and out the wafer.
[0013]
The outer tube 3 is formed in a cylindrical shape whose inner diameter is larger than the outer diameter of the inner tube 2 and whose upper end is closed and whose lower end is opened. The outer tube 3 is concentrically covered with the inner tube 2 so as to surround the outer tube. The lower end between the inner tube 2 and the outer tube 3 is hermetically sealed by a manifold 6 formed in a circular ring shape, and the manifold 6 is used to replace the inner tube 2 and the outer tube 3 with each other. 2 and the outer tube 3 are detachably attached. Since the manifold 6 is supported by the casing 17 of the CVD apparatus, the process tube 1 is vertically installed.
[0014]
An exhaust pipe 7 is connected to an upper portion of a side wall of the manifold 6, and the exhaust pipe 7 is connected to an exhaust device (not shown) so that the processing chamber 4 can be evacuated to a predetermined vacuum. I have. The exhaust pipe 7 is in communication with a gap formed between the inner tube 2 and the outer tube 3, and the gap between the inner tube 2 and the outer tube 3 allows the exhaust path 8 to have a constant cross-sectional shape. Is formed in a circular ring shape. Since the exhaust pipe 7 is connected to the manifold 6, the exhaust pipe 7 has a cylindrical hollow body and is arranged at the lowermost end of a vertically extending exhaust path 8. A gas inlet pipe 9 is connected to a lower portion of the side wall of the manifold 6 so as to communicate with the furnace port 5 of the inner tube 2. The gas inlet pipe 9 is connected to a raw material gas supply device and a carrier gas supply device (both shown in the drawing). Connected). The gas introduced into the furnace port 5 by the gas introduction pipe 9 flows through the processing chamber 4 of the inner tube 2, passes through the exhaust path 8, and is exhausted by the exhaust pipe 7.
[0015]
A seal cap 10 for closing the lower end opening is brought into contact with the manifold 6 from below in the vertical direction. The seal cap 10 is formed in a disk shape substantially equal to the outer diameter of the outer tube 3, and is configured to be vertically moved up and down by an elevator (not shown) installed vertically outside the process tube 1. I have. A boat 11 for holding a wafer W as a substrate to be processed is vertically supported on the center line of the seal cap 10.
[0016]
The boat 11 has a pair of upper and lower end plates 12 and 13 at the top and bottom, and a plurality of boats (three in the present embodiment) standing vertically between the upper end plate 12 and the lower end plate 13. The holding members 14 are provided, and a large number of holding grooves 15 are formed in the three holding members 14 at equal intervals in the longitudinal direction so as to be open to face each other. The boat 11 is configured such that the wafers W are inserted between the holding grooves 15 of the three holding members 14 so that the plurality of wafers W are aligned and held horizontally and with their centers aligned. . A heat insulating cap 16 is disposed between the boat 11 and the seal cap 10. The heat insulating cap 16 supports the boat 11 in a state of being lifted from the upper surface of the seal cap 10, thereby lowering the lower end of the boat 11. It is configured to be separated from the position of the mouth 5 by an appropriate distance.
[0017]
Outside the outer tube 3, a heater unit 20 for heating the inside of the process tube 1 is provided concentrically so as to surround the outer tube 3. The heater unit 20 includes a case 21 made of stainless steel (SUS) and formed in a cylindrical shape with an upper end closed and a lower end opened. The inner diameter and the overall length of the case 21 are larger than the outer diameter and the overall length of the outer tube 3. Is set. Inside the case 21, a heat insulating wall 23 constructed in a cylindrical shape slightly larger than the outer diameter and the entire length of the outer tube 3 is provided with a gap 22 as a space for air cooling between the outer wall 3 and the inner peripheral surface of the case 21. And are installed concentrically. The heat insulating wall 23 has a disc-shaped ceiling wall 24 having an outer diameter equal to the inner diameter of the case 21, an inner diameter slightly larger than the outer diameter of the outer tube 3, and an outer diameter smaller than the inner diameter of the case 21. And a cylindrical side wall 25. The ceiling wall portion 24 is covered on the upper end surface of the side wall portion 25 so as to close the opening, and the upper end surface of the ceiling wall portion 24 is in contact with the lower surface of the ceiling wall of the case 21. Since the outer diameter of the side wall portion 25 is set smaller than the inner diameter of the case 21, a gap 22 as an air cooling space is formed between the side wall portion 25 and the case 21. Further, a plurality of heat insulating blocks 26 shown in FIG. 2 are vertically stacked on the side wall portion 25 of the heat insulating wall 23 to form a single cylindrical body.
[0018]
As shown in FIG. 2, the heat insulating block 26 includes a donut-shaped main body 27 that is a short cylindrical shape, and the main body 27 is vacuum-formed using a fibrous or spherical insulating material such as alumina or silica. It is integrally molded by a molding method of the foam method. At the lower end of the main body 27, an inlay connecting male part 28 is formed with a part of the outer periphery cut out in a circular ring shape. The portion is formed in a state of being cut out in a circular ring shape. Between the lower end of the inner peripheral surface of the main body 27 and the upper end of the female part 29, a mounting groove 30 for mounting a heating element is submerged at a constant depth and a constant height. A plurality of holders 31 for positioning and holding the heating element are mounted on the peripheral surface at equal intervals in the circumferential direction.
[0019]
Heating element 32 is used resistance heating material such as Fe-Cr-Al alloy and MOSi ₂ and SiC, as shown in FIG. 2, integrally formed by pressing or laser cutting, etc. into a flat plate shape of the waveform It is rounded into a circular ring shape having a diameter slightly smaller than the inner diameter of the mounting groove 30 of the heat insulating block 26 and partially having a cutout portion 34. As shown in FIG. 2, in a state where the heating element 32 is in contact with the inner peripheral surface of the mounting groove 30, each of the holders 31 is held by being inserted into the corrugated gap 33. I have. As shown in FIG. 2 and FIG. 3, a pair of power supply portions 35 and 36 are formed at both ends of the cutout portion 34 of the heating element 32 by being bent at right angles outward in the radial direction, respectively. A pair of connecting portions 37 and 38 are formed at the distal ends of the power feeding portions 35 and 36 at right angles to each other. The cross-sectional area of the pair of power supply units 35 and 36 is set smaller than in the related art in order to effectively generate heat in the power supply units 35 and 36 by increasing the section resistance value in the pair of power supply units 35 and 36.
[0020]
A pair of insertion grooves 39 and 40 are formed at positions corresponding to the pair of power supply portions 35 and 36 in the mounting groove 30 of the main body 27 of the heat insulating block 26 so as to extend in the radial direction, respectively. The reference numerals 35 and 36 are inserted into the insertion grooves 39 and 40 from the mounting groove 30 side to the outer peripheral side of the main body 27, respectively. A holder insertion hole 41 is provided in the inner peripheral surface of the mounting groove 30 between the insertion grooves 39 and 40 in a radial direction, and a holder 42 is inserted into the holder insertion hole 41. As shown in FIGS. 3A and 3B, the holder 42 is made of a heat-resistant ceramic such as alumina or silica and is integrally formed into a substantially rectangular parallelepiped by an appropriate manufacturing method such as a sintering method. It is fixed to the main body 27 by being fitted into the holder fitting hole 41. A pair of holding grooves 43 and 44 are formed at positions corresponding to the two insertion grooves 39 and 40 on the upper surface of the holder 42, and the two holding grooves 43 and 44 are inserted into the two insertion grooves 39 and 40 respectively. Feeding portions 35 and 36 are inserted respectively. The holding grooves 43, 44 of the holder 42 are configured to hold the power supply portions 35, 36 of the heating element 32 so as to prevent the heating element 32 from running up. The insertion grooves 39 and 40 of the main body 27 are set relatively narrow (small).
[0021]
As shown in FIG. 3, a power supply terminal 45 is welded to one connection portion (hereinafter, referred to as a positive connection portion) 37 of the upper heating element 32, and the other connection portion (hereinafter, referred to as a positive connection portion). The upper end of the crossover 46 is welded to the minus connection 38. The lower end of the crossover 46 is connected to the plus connection 37 of the lower heating element 32. Therefore, the plus side connection part 37 of the lower heating element 32 is located immediately below the minus connection part 38 of the upper heating element 32, and the cutout part 34 of the lower heating element 32 is accordingly It is in a state of being shifted in the circumferential direction from the notch 34 of the heating element 32 on the side. As described above, the notches 34 of the heat generating elements 32 adjacent to each other in the upper and lower directions are displaced from each other in the circumferential direction. Can be dispersed, and influence on the heating temperature distribution of the plurality of heating elements 32 can be prevented. The connecting wire 46 in order to reduce suppress the heat radiation from the surface of the connecting wire 46, Fe-Cr-Al alloy and MOSi ₂ and the resistance heating material such as SiC is used, and is formed into a round bar shape. Incidentally, by forming the crossover wire 46 into a round bar shape, the surface area can be reduced by about 20% of the square bar shape having the same cross-sectional area. However, depending on the current capacity of the crossover, the crossover 46 may be formed in a square rod shape.
[0022]
As shown in FIG. 4, a terminal case 47 that covers both the connection portions 37 and 38 and the connecting wire 46 is provided at a position corresponding to the installation location of the power supply terminal 45 on the outer peripheral surface of the case 21 of the heater unit 20. The terminal case 47 is filled with a heat insulating material (not shown) such as glass wool. A plurality of power supply terminals 45 are inserted into the terminal case 47 via an insulator 48.
[0023]
Next, construction work of the heater unit 20 will be described.
[0024]
In constructing the heater unit 20, the number of the heat insulating blocks 26 according to the above configuration specified in accordance with the length of the side wall 25 of the heat insulating wall 23 is prepared. At this time, the same number of the heat insulating blocks 26 may be integrally formed by a vacuum-forming method regardless of the length specification of the heat insulating wall 23, so that the manufacturing cost of the heat insulating wall 23 is extremely small. be able to. Before the assembling work of the heat insulating wall 23 by the plurality of heat insulating blocks 26, the heat generating body 32 is mounted in the mounting groove 30 of each heat insulating block 26. A plurality of heat-insulating blocks 26 are stacked one after another while the ink-joining female portion 29 of the lower heat-insulating block 26 is fitted into the ink-joining male portion 28 of the upper heat-insulating block 26 and the upper and lower heat-insulating blocks 26 are joined together. As a result, the side wall 25 of the heat insulating wall 23 having the designated length is assembled. When the upper and lower heat insulating blocks 26, 26 are stacked, the heating elements 32, 32 of the upper and lower heat insulating blocks 26, 26 are electrically connected to each other in series. Thus, in a state where one heat insulating wall 23 is assembled, as shown in FIG. 1, the plurality of heating elements 32 are in a state of one spiral heater 49. In addition, since each heating element 32 is formed in a waveform, the entire length of the heater 49 is extremely long. Therefore, the linear density of the heater 49 becomes extremely large, and the heater characteristics such as the temperature recovery time become very good.
[0025]
The ceiling wall portion 24 is put on the side wall portion 25 assembled as described above. After that, the case 21 is put on the heat insulating wall 23 which is an assembly of the side wall 25 and the ceiling wall 24, and the heater unit 20 is constructed. Incidentally, the case 21 in which the ceiling wall portion 24 is laid on the lower surface of the ceiling wall may be covered on the side wall portion 25. The gap 22 formed between the outer periphery of the heat insulating wall 23 and the inner periphery of the case 21 in the heater unit 20 in which the case 21 covers the heat insulating wall 23 forms a good heat insulating layer by itself. However, when air is blown into the gap 22, the heat insulating wall 23 can be forcibly cooled, so that the temperature lowering speed of the heater unit 20 can be set faster.
[0026]
Since the operation of the heater unit 20 constructed as described above in the film forming process is the same as that of the conventional heater unit, the description of the operation of the film forming process by the CVD apparatus according to the above configuration will be omitted.
[0027]
According to the embodiment, the following effects can be obtained.
[0028]
1) By holding the pair of power supply units of the heating element in a state in which they are insulated from each other by the heat-resistant holder, the pair of power supply units held by the holder can be brought close to each other. Can be suppressed to a minimum.
[0029]
2) By displacing the pair of power supply units of the plurality of heating elements in the circumferential direction, the power supply unit, which is a part where the temperature of the heating elements decreases, can be dispersed. The influence can be suppressed.
[0030]
3) By setting the cross-sectional area of the pair of power supply sections to be small, the section resistance value in the power supply section can be increased and the power supply section can also generate heat effectively. Can be prevented.
[0031]
4) By forming the crossover in the shape of a round bar, heat radiation from the surface of the crossover can be suppressed to a small extent, so that it is possible to prevent a decrease in temperature at the power supply section of the heating element.
[0032]
5) By covering a terminal case for covering the connection portion and the crossover wire at a position corresponding to the installation position of the power supply terminal on the outer peripheral surface of the heater unit case, and filling the inside of the terminal case with a heat insulating material such as glass wool. In addition, since the heat radiation at the connection portion and the crossover can be suppressed, it is possible to prevent the temperature at the power supply portion of the heating element from decreasing.
[0033]
Note that the present invention is not limited to the above-described embodiment, and it goes without saying that various changes can be made without departing from the gist of the present invention.
[0034]
For example, the heating element is not limited to winding one turn (one turn) around the heat insulating block, and may be wound two turns (two turns) or more. Further, the mounting structure of the heating element is not limited to being configured to be mounted in the mounting groove by the holding tool as in the above-described embodiment, and is configured such that an anchor protruding from the heating element is inserted into the main body of the heat insulating block and mounted. Alternatively, the heating element may be configured to be attached to the heat insulating block by an attachment pin.
[0035]
The case is not limited to providing a gap between the heat insulating wall and the case, and the case may be covered so as to be in close contact with the heat insulating wall.
[0036]
The heater unit, the heat insulating wall, the case, and the like are not limited to being formed in a cylindrical shape, and may be formed in a square cylindrical shape or a polygonal cylindrical shape.
[0037]
The CVD apparatus is not limited to the batch type vertical hot wall type reduced pressure CVD apparatus, and may be another CVD apparatus such as a horizontal hot wall type reduced pressure CVD apparatus.
[0038]
Further, the semiconductor manufacturing apparatus is not limited to the CVD apparatus, but may be an oxide film forming apparatus, a diffusion apparatus, or a heat treatment apparatus (thermal treatment) such as reflow and annealing for carrier activation or planarization after ion implantation (thermal treatment). Furnace) can be applied to all semiconductor manufacturing apparatuses.
[0039]
【The invention's effect】
According to the present invention, since the temperature distribution in the substrate surface can be improved, the number of sheets processed in a unit time is increased, which greatly contributes to the improvement of the throughput and the production efficiency. Performance can be improved.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a CVD apparatus according to an embodiment of the present invention.
FIGS. 2A and 2B show a main part of the heater unit, wherein FIG. 2A is a perspective view and FIG. 2B is a side sectional end view.
3 (a) is a plan view, FIG. 3 (b) is a view along arrow bb in FIG. 3 (a), and FIG. 3 (c) is a front view.
FIG. 4 is a perspective view of a heater unit.
[Explanation of symbols]
W: Wafer (substrate), 1: Process tube, 2: Inner tube, 3: Outer tube, 4: Processing chamber, 5: Furnace, 6: Manifold, 7: Exhaust pipe, 8: Exhaust path, 9: Gas introduction Pipe 10 seal cap 11 boat 12 13 end plate 14 holding member 15 holding groove 16 heat insulating cap part 17 housing 20 heater unit 21 case 22 Gap, 23: heat-insulating wall, 24: ceiling wall, 25: side wall, 26: heat-insulating block, 27: main body, 28: male porcelain connecting male part, 29: female porcelain connecting female part, 30: mounting groove, 31 ... holding 32, heating element, 33, gap, 34, notch, 35, 36, power supply, 37, 38, connection, 39, 40, insertion groove, 41, holder insertion hole, 42, holder, 43, 44 ... holding groove, 45 ... power supply terminal, 46 ... crossover, 47 ... end Case, 48 ... insulator, 49 ... heater.

Claims (2)

A heating element having a pair of power supply units is laid on the inner periphery of a heat-insulating wall formed in a cylindrical shape, and the pair of power supply units is held in a state insulated from each other by a heat-resistant holder. Characteristic semiconductor manufacturing equipment. A plurality of heating elements having a pair of power supply units are arranged in the same direction as the cylinder core on the inner periphery of the heat-insulating wall formed in a cylindrical shape, and the pair of power supply units of these heating elements are arranged in the circumferential direction. A semiconductor manufacturing apparatus characterized by being shifted.

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