JP2004031395A - Semiconductor manufacturing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the uniformity of a film thickness in a substrate surface by eliminating ununiform part of process gas flow caused by a substrate mounting member. <P>SOLUTION: In a semiconductor manufacturing equipment, a boat on which a wafer is mounted is inserted into a reactant tube. A reactant gas is introduced into the heated reactant tube, to grow a thin film on the wafer. The boat comprises a plurality of supporting columns 21 and a lot of ring-like mounting plates 20. A plurality of wafer supporting protrusions 17 are formed on a top surface of each mounting plate 20. The plate 20 is further provided with a plurality of insertion holes 24 for the supporting column that are for inserting the supporting column 21. The insertion hole 24 is so opened as to fall within a width of the plate, so that the supporting column 21 does not protrude from the mounting plate 21. A lot of mounting plates 21 in which the insertion hole 24 is opened are laminated with proper intervals, and the insertion holes 24 are aligned to temporarily fix the plates with a fixture. The boat is assembled by inserting the supporting column into the insertion holes 24 of each mounting plate 21 to fix by welding. <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 a substrate mounting member that affects a gas flow.
[0002]
[Prior art]
Generally, a semiconductor manufacturing apparatus includes a boat as a substrate mounting member for loading a plurality of wafers in multiple stages, a reaction tube for inserting the boat, and a heater for surrounding the reaction tube and heating the wafer loaded on the boat. And a film forming process is performed on the wafer surface by flowing a processing gas through the reaction tube.
[0003]
FIG. 7 shows a main part view of a conventional boat as a substrate mounting member used in the above-described semiconductor manufacturing apparatus. The boat includes a plurality of ring-shaped mounting plates 16 for holding wafers one by one, and a plurality of (four) columns 15 for supporting them. A plurality (three) of support protrusions 17 for supporting a wafer are provided on the upper surface of the mounting plate 16. The column 15 has a circular cross section, and has grooves for holding a mounting plate provided in multiple stages on one side. A plurality of pillars 15 are arranged and fixed in a semicircular shape such that the groove provided in each pillar 15 faces the center of the circle. A mounting plate is inserted into a space surrounded by the plurality of columns 15 from a specific direction (the side where the columns are not arranged), and the outer periphery of each mounting plate 16 is welded to a groove provided in the column 15 to form a plurality of plates. A boat for loading the wafers in multiple stages is assembled. The bulge on the outer periphery of the column indicates the welded portion 25.
[0004]
The problem in the boat shown in FIG. 7 is that the mounting plate 16 is attached from the inside of the columns 15 arranged in a semicircular shape, so that the mounting plate is limited by the thickness a remaining in the groove of the column 15. This is a point protruding from the outer diameter of No. 16. The smaller the gap between the reaction tube and the boat (the contour of the boat is determined by the outer diameter of the mounting plate), the more uniform the gas flow becomes. However, the outer diameter of the boat cannot be increased by the thickness a. The gap with the boat cannot be reduced. Therefore, a downflow occurs in the gap between the reaction tube and the boat, and the flow of the processing gas becomes uneven.
[0005]
Therefore, a boat was considered in which the columns did not protrude from the outer diameter of the mounting plate. FIG. 8 shows an example of such a boat. The pillars are semicircular in cross section. A plurality of notches 18 for supporting column insertion are provided at a plurality of places (four places) on the outer periphery of the ring-shaped mounting plate 16. A mounting plate 16 provided with a notch 18 is inserted into a space surrounded by a plurality of (four) columns 15 fixedly arranged on a semicircle from a specific direction, and the column 15 is inserted into each notch 18. A boat is assembled by welding and stacking a plurality of wafers in multiple stages.
[0006]
In the boat shown in FIG. 8, since the columns do not protrude from the mounting plate 16, the mounting plate 16 can have a maximum outer diameter, and the gap between the reaction tube and the boat can be reduced. However, since the mounting plate 16 needs to be inserted into the support space from a specific direction, the insertion position of the support is shallow at the two deep positions where the mounting plate 16 is inserted. Since the insertion position becomes deeper at the two positions, the cutout portion 18 must be largely cut. For this reason, the notch 18 provided on the mounting plate 16 becomes a portion where the thermal flow is uneven and the gas flow is uneven, and the film thickness at the notch tends to be thin even in the film formation result.
[0007]
[Problems to be solved by the invention]
As described above, in the substrate mounting member constituting the conventional semiconductor manufacturing apparatus, in the type in which the mounting plate is held in the mounting plate holding groove provided in the support, the support protrudes from the outer diameter of the mounting plate. Therefore, the gap between the reaction tube and the mounting plate cannot be reduced, and the flow of the processing gas cannot be uniform.
[0008]
In the case of a type in which the support is inserted into the notch for inserting the support provided on the mounting plate, it is possible to take the maximum outer diameter of the mounting plate, but the notch for inserting the support is not thermally insulated. There has been a problem that the gas flow becomes uniform and uneven.
[0009]
An object of the present invention is to eliminate the above-mentioned problems of the prior art and to improve the uniformity of the film thickness in the plane of the substrate by eliminating the uneven portion of the gas flow caused by the substrate mounting member. An object of the present invention is to provide a possible semiconductor manufacturing apparatus.
[0010]
[Means for Solving the Problems]
A first invention relates to a semiconductor manufacturing apparatus that inserts a substrate mounting member in which a plurality of substrates are stacked in multiple stages into a reaction tube and heats the substrate in the reaction tube while flowing a processing gas into the reaction tube to form a film. The substrate mounting member has a plurality of ring-shaped mounting plates on which the substrates are mounted one by one, and a plurality of support insertion holes that fit within the plate width are opened in each mounting plate, and the support support insertion is performed. A plurality of mounting plates are stacked so that the holes are aligned with each other, a support is inserted into each support insertion hole, and the mounting plates are fixed to the support in a horizontal posture at desired intervals.
[0011]
A plurality of substrates are stacked on each mounting plate of the substrate mounting member. The substrate placing member on which the substrate is loaded is inserted into the reaction tube. The substrate loaded on the substrate placing member is heated by the heating means. The processing gas is exhausted while flowing the processing gas through the reaction tube. Thereby, a film is formed on the substrate surface. The support plate is inserted into the mounting plate by opening a support insertion hole that fits within the width of the plate, and unlike the case where the outer periphery of the mounting plate is held in the groove provided in the support, the support is It fits within the width and does not protrude from the outer periphery of the mounting plate. Therefore, the gap between the reaction tube and the substrate mounting member can be minimized, and the formation of a harmful downflow with a uniform film thickness can be prevented. Also, since it is not necessary to form the outer periphery of the mounting plate to mount the support, unlike the case where a notch for inserting the support is provided in the outer periphery of the mounting plate, the outer circumference of the mounting plate remains circular. Up to. Therefore, an uneven portion of the gas flow due to the shape of the mounting plate does not occur.
[0012]
In the first invention, it is preferable that not only the shape of the mounting plate but also the cross section of the column be streamlined so that the gas flow is not disturbed by the column. The streamline is, for example, a spindle type. Preferably, the mounting plate of the substrate mounting member is provided with at least three support projections for supporting the substrate by floating the mounting plate. This is for simplifying the transfer of the substrate into and out of the substrate mounting member by the substrate transfer device.
[0013]
Further, in the first invention, the reaction tube is constituted by a double tube of an outer tube and an inner tube arranged coaxially in the outer tube, arranged on one side in the inner tube, and inserted into the inner tube. A nozzle having a plurality of ejection holes for supplying gas to each substrate mounted on the substrate mounting member to be mounted, and a nozzle opened on the inner tube wall on the other side facing the nozzle and introduced into the inner tube via the nozzle A slit-shaped opening for letting out the extracted gas from the inner tube, and an exhaust passage for discharging the gas led out of the inner tube through the slit-shaped opening from the reaction tube through a space between the inner tube and the reaction tube. It is preferable to provide the following.
[0014]
When a slit-shaped opening is provided in the inner pipe wall on the other side opposite to the nozzle disposed on one side in the inner pipe, gas introduced from the nozzle to the inner pipe can be placed on each of the substrate mounting members. It passes through the substrate in parallel with the substrate surface and is led out of the inner tube. At this time, if the gap between the reaction tube and the substrate placing member is reduced by setting the substrate placing member to the maximum outer diameter, a downflow does not occur in this gap, and the inner tube and the outer tube pass through the slit-shaped opening. The gas is exhausted from the reaction tube through the space formed between the reaction tubes. Therefore, the gas flow on the substrate surface is not disturbed, and the gas is smoothly exhausted.
[0015]
According to a second aspect of the present invention, there is provided a semiconductor manufacturing apparatus in which a substrate mounting member in which a plurality of substrates are stacked in multiple stages is inserted into a reaction tube, and a substrate in the reaction tube is heated while a gas is flowing through the reaction tube to form a film. In the method, when the substrate mounting member is manufactured, a plurality of mounting plates for mounting the substrates one by one are prepared, and a support hole is formed in each mounting plate, and a support hole is formed. A plurality of the mounting plates were temporarily fixed using a jig in a state where the insertion holes for the columns were aligned and stacked, and the columns were inserted into the insertion holes for the columns of the temporarily fixed mounting plates and inserted. The supporting column is fixed to the mounting plate, and the jig is removed after the fixing.
[0016]
Since the columns are inserted into the column insertion holes of the respective mounting plates so that the plurality of mounting plates temporarily fixed by using the jig are skewered, the substrate mounting member can be easily assembled.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0018]
FIG. 4 shows an overall configuration diagram of the semiconductor manufacturing apparatus. The semiconductor manufacturing apparatus includes a cassette stocker 1 on which a wafer cassette 30 is mounted, a wafer transfer means 2 for transferring wafers between the cassette stocker 1 and the boat 3, and a substrate mounting means for stacking a plurality of wafers in multiple stages. It comprises a boat 3 as an installation member, a boat elevating means 4 for inserting and pulling the boat 3 into and out of the reaction tube, and a heat treatment apparatus 5 having a reaction tube and a heater for heating the reaction tube.
[0019]
The heat treatment apparatus is, for example, a vertical CVD apparatus. FIG. 5 shows the internal configuration of such a vertical CVD apparatus. A reaction tube 31 made of quartz is provided inside the cylindrical heater 12. The reaction tube 31 includes an outer tube 7 having a closed upper end, and an inner tube 6 having a closed upper end and disposed concentrically inside the outer tube 7. A reaction chamber 32 for processing the wafer 11 is formed by the inner tube 6. The reaction tube 31 is erected on the metal furnace flange 10. The lower end of the furnace port flange 10 is hermetically closed by a seal cap 33, and the boat 9 is erected on the seal cap 33 and inserted into the inner pipe 6. The wafers 7 to be processed are stacked on the boat 9 in multiple stages in a horizontal posture.
[0020]
The gas inlet nozzle 8 is attached to the furnace opening flange 10, rises inside the furnace opening flange, is inserted into the inner pipe 6, and extends above the boat 9. The gas introduction nozzle 8 is provided with a large number of nozzle holes 35 in accordance with the arrangement of the wafers stacked in multiple stages. On the tube wall of the inner pipe 6 opposed to the gas introduction nozzle 8 provided with the nozzle hole 35, a slit-shaped opening 14 for leading out the gas introduced into the inner pipe 6 from the gas introduction nozzle 8 is provided. The slit-shaped openings 14 are provided in multiple stages like the nozzle holes 35. The derived gas flows into a cylindrical space 23 formed between the outer pipe 7 and the inner pipe 6, and is discharged from an exhaust port 13 provided in the furnace port flange 10. The space 23 and the exhaust port 13 form an exhaust path.
[0021]
The boat 9 is lowered by the boat elevating means 4, the wafers 7 are loaded into the boat 9 in multiple stages, and the boat 9 is inserted into the inner pipe 6 by the boat elevating means 4. After the seal cap 33 completely seals the lower end of the furnace port flange 10, the inside of the reaction chamber 32 is evacuated to reduce the pressure.
[0022]
The inside of the inner tube 6 is heated to a predetermined film forming temperature by the heater 12. The boat 9 is rotated by the rotation drive unit 26. A processing gas is introduced from the gas introduction nozzle 8 into the reaction tube 6. The processing gas is ejected from the nozzle holes 8, passes over the stacked wafers in parallel with the wafer surface, is led out of the reaction tube 6 through the slit-shaped opening 14, passes through the space 23, and passes through the gas exhaust port. 13 to be discharged. When the processing gas passes over the wafer, a film is formed on the surface of each wafer 7. After the film formation, an inert gas is introduced from the gas introduction nozzle 8, and the inside of the reaction tube 31 is replaced with the inert gas to return to normal pressure. The boat 9 is lowered, and the wafers 7 after film formation are discharged from the boat 9.
[0023]
Here, the flow of gas in the inner pipe 6 will be described with reference to FIG. 6A shows a case where the gap t between the inner pipe 6 and the outer diameter of the boat 9 is small, and FIG. 6B shows a case where the gap is large.
[0024]
As shown in FIG. 6A, when the processing gas is injected from a direction parallel to the surface of the wafer 11, a gap t between the inner pipe 6 and the outer diameter of the boat 9 is set in order to make the flow of the processing gas uniform. Must be as small as possible. This is because, after the processing gas discharged from the nozzle 8 is introduced along the ring-shaped mounting plate 16 and passes through the surface of the wafer 11, the gas flow is not disturbed as it is, and the slit provided in the inner pipe 6 is provided. This is because it is drawn out from the opening 14 and exhausted from the space 23. On the other hand, as shown in FIG. 6B, when the gap t is large, a downflow 19 as indicated by an arrow occurs in the space 34 between the inner pipe 6 and the outer diameter of the boat 9 and the reaction chamber 32 The exhaust becomes uneven in the vertical direction, which affects the uniformity of the film thickness of the wafer 11.
[0025]
In order to make the gap t as small as possible, as described above, it is necessary to prevent the columns constituting the boat 9 from protruding from the ring-shaped mounting plate 16. In addition, it is required that the outer shape of the ring-shaped mounting plate 16 is not deformed even if the pillar does not protrude.
[0026]
Therefore, in the embodiment, the boat constituting the boat 9 is configured as shown in FIGS. 1 and 2. 1A and 1B are explanatory views of a mounting plate constituting a boat, wherein FIG. 1A is a side view and FIG. 1B is a plan view. FIG. 2 is an overall configuration diagram of the boat.
[0027]
The boat 9 is made of quartz, and has a bottom disk 41, four columns 21 and a top disk 42 as shown in FIGS. The four columns 21 are arranged and fixed in a semicircular shape on the bottom disk 41. The top disk 42 is fixed to the upper ends of the four columns 21. Circular holes 43 and 44 are formed in the center portions of the bottom disk 41 and the top disk 42, respectively, so that the processing gas can easily enter the inside of the boat 9. Between the bottom disk 41 and the top disk 42, a plurality of ring-shaped mounting plates 20 that are stacked at desired intervals in multiple stages in a horizontal posture are fixed by columns 21. The ring-shaped mounting plate 20 is formed in a substantially circular shape with an opening at the center, and a plurality of (for example, three) wafer support projections 17 are formed on the upper surface to float and support the wafer from the mounting plate. . Further, the support plate 20 is formed with four support hole insertion holes 24 for inserting the four supports 21. The four support hole insertion holes 24 are formed at appropriate intervals on a half circle on one half of the mounting plate 20. The support insertion hole 24 is opened so as to fit within the plate width of the mounting plate 20, and is not opened outside or inside. The gas flow is disturbed when the support is protruded outward from the mounting plate 20 when the support is opened outward, and the wafer cannot be inserted into the boat when the support is protruded inward from the support plate 20 when the support is protruded inward from the mounting plate 20. is there. The columns 21 are inserted into the four column insertion holes 24, respectively, and the mounting plates 20 are welded and fixed at desired intervals in a horizontal posture.
[0028]
In order to manufacture the boat 9, here, a method is adopted in which a mounting plate 20 temporarily fixed in multiple stages horizontally is inserted from above the support column 21 using a jig (not shown) and welded. That is, a plurality of ring-shaped mounting plates 20 having the support hole 24 are prepared. A plurality of mounting plates 20 are temporarily fixed with a jig in a state where the mounting plates 20 are aligned and stacked so that the respective support insertion holes 24 are aligned. The four columns 2 are arranged in a semicircular shape and fixed to the bottom disk 43. The column 21 is inserted into the column insertion holes 24 of the plurality of temporarily fixed mounting plates 20, and the inserted column 21 is fixed to the mounting plate 20 at the column insertion holes. The ceiling disk 42 is fixed to the support 21. When the jig is removed, a boat in which many wafers are stacked in multiple stages is completed. Note that the fixing between the boat members including the fixing of the mounting plate 20 is performed by welding quartz glass to each other. Although the mounting plate 20 is inserted from the upper part of the column 21, it may be inserted from the lower part. The mounting plate is not particularly limited as long as it has heat resistance. However, in addition to quartz, a heat-resistant material such as cesium carbide (SiC), alumina (Al ₂ O ₃ ), and ceramic is preferable.
[0029]
In the boats of FIGS. 1 and 2 according to the embodiment, since there is no projecting portion of the pillar portion, it is possible to minimize the gap t between the inner tube and the mounting plate portion. When the gas is injected, the gas passes in parallel with the wafer surface, and is discharged from the exhaust port 13 through the space 23 through the slit-shaped opening without any downflow. Therefore, the flow of the processing gas in the vertical direction in the reaction chamber 32 does not become uneven. Further, since there is no notch on the outer periphery of the mounting plate and the outer circumference of the mounting plate keeps a circular shape, thermal uniformity and uniformity in gas flow are not impaired. Therefore, the thermal effect on the wafer can be made uniform and the flow of the processing gas can be made uniform, and the uniformity of the film thickness in the processing wafer surface can be improved. As a result, it is possible to improve the quality in manufacturing the semiconductor element.
[0030]
In the embodiment, the case has been described in which the column insertion hole 24 is opened so as to fit within the plate width of the mounting plate 20 and is not opened outside. However, even if a part of the support hole 24 is opened outside the plate, the support hole inserted there closes the opening of the insertion hole, and as a result, the outer periphery of the mounting plate is held in a circular shape. I just need.
[0031]
In addition, the case where the insertion hole for the support and the support inserted into the support have a circular shape and a circular cross-section are shown, but the cross-section of the support should be streamlined so as not to disturb the gas flow in the horizontal gas flow. Is preferred. As shown in FIG. 3, for example, the cross section has a spindle shape, and the protruding portions of the columns are directed to the upstream side and the downstream side of the gas flow, so that the horizontal gas flow is hardly disturbed. When performing the film forming process while the boat is stopped, it is preferable that the directions of the columns are all parallel to the gas flow as illustrated. Thus, the gas flow is not disturbed by the columns 21, and the uniformity of the film thickness in the surface of the processing wafer can be further improved.
[0032]
FIG. 3 shows a particularly effective example in the case where the film formation process is performed while the boat is stopped. However, in the case where the process is performed by rotating the boat, the direction of the columns is changed as shown in FIG. As shown in FIG. In the case of FIG. 9A, when the column 21 comes closest to the gas introduction nozzle 8 by the rotation of the boat (in the direction of the thick arrow) (FIG. 9B), the column 21 closes from the nozzle hole 35 by the column 21 that comes close. This is an example in which one end of the protruding portion of all the columns 21 is directed to the rotation center so that the flow (arrow) of the energetic processing gas immediately after the ejection is not disturbed. Thereby, even if the column 21 approaches the gas introduction nozzle 8, the disturbance is reduced, and the uniformity in the wafer surface can be improved.
[0033]
【The invention's effect】
According to the present invention, the uneven portion of the gas flow caused by the substrate mounting member can be eliminated, so that the uniformity of the film thickness in the substrate surface can be improved. Therefore, it is possible to improve the quality in manufacturing the semiconductor element.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a mounting plate constituting a boat used in a semiconductor manufacturing apparatus according to an embodiment, wherein (a) is a side view and (b) is a plan view.
FIG. 2 is an overall configuration diagram of a boat according to the embodiment.
FIG. 3 is an explanatory view showing a modified example of a column supporting a mounting plate according to the embodiment.
FIG. 4 is an overall configuration diagram of a semiconductor manufacturing apparatus according to an embodiment.
FIG. 5 is a configuration diagram of a heat treatment apparatus according to an embodiment.
6A and 6B are explanatory diagrams showing a relationship between a distance between an inner tube and a mounting plate and a gas flow according to the embodiment, wherein FIG. This shows the case where the gap is large.
FIG. 7 is a configuration diagram of a mounting plate configuring a boat according to a conventional example.
FIG. 8 is a configuration diagram of a mounting plate constituting a boat according to another conventional example.
FIGS. 9A and 9B are explanatory views showing a modified example of a column supporting the mounting plate according to the embodiment, wherein FIG. 9A is an overall view and FIG. 9B is a partially enlarged view.
[Explanation of symbols]
9 Boat (substrate mounting member)
11 Wafer (substrate)
12 heater (heating means)
21 Support 20 Mounting plate 24 Support insertion hole 31 Reaction tube

Claims (1)

In a semiconductor manufacturing apparatus that inserts a substrate mounting member in which a plurality of substrates are stacked in multiple stages into a reaction tube and heats the substrate in the reaction tube while flowing gas into the reaction tube to form a film,
The substrate mounting member includes a plurality of ring-shaped mounting plates for mounting the substrate one by one,
The mounting plate has a plurality of strut insertion holes opened to fit within the plate width, and is stacked in multiple stages so that the strut insertion holes match.
A semiconductor manufacturing apparatus wherein a support is inserted into each support insertion hole and fixed between mounting plates at desired intervals.

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