JP2000294511A - Manufacture for semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a film at a high speed by a method wherein, when a semiconductor silicon wafer is entered and exited outside a heating furnace, a movable wafer entering and exiting member is provided between the semiconductor silicon wafer and a plate-like substrate. SOLUTION: In a support structure of a wafer 5, the appropriate number of pins 19, for example, four, or six ones, at an equal angle are projected from a substrate 18 composed of a quartz disk, or the like, so that the wafer 5 is supported from a downside. In this support method, as the wafer 5 is not supported at a center, it has a tendency to warp, but even a 12-inch wafer is not caused to warp problematically if heating temperatures are 900 deg.C or less. A height of the pin 19 is such a value that a fork 26 can be entered into and exited from a space between the wafer 5 and the substrate 18 when a wafer hoisting mechanism is faller down and the wafer 5 is moved outside a furnace. Furthermore, a clearance between the substrate 18 and an inner wall of a reaction pipe is a narrow clearance in which a reaction gas flow jetted parallel to an upper face of each wafer 5 is hard to flow to upper and lower wafers of each wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly, to a conventional method of chemical vapor deposition (CVD) of a semiconductor silicon wafer by a batch process or a reaction gas. The present invention relates to an improvement of a method for forming a film on a wafer by a direct reaction, and relates to a semiconductor device manufacturing apparatus for increasing the growth rate of these films.

[0002]

2. Description of the Related Art As a method of performing uniform CVD on a large-diameter silicon wafer having a diameter of 6 to 8 inches, Si is used as a method.
It is known to form a film by rotating a single semiconductor wafer placed laterally on a C susceptor and flowing a reaction gas horizontally over the wafer surface while heating the lamp. The feature of this method is that the reaction wall such as SiH ₄ hardly adheres to the furnace wall due to the cold wall method in which the wall of the reaction furnace is cooled; there is relatively little generation of particles there; and rapid heating is easy. And so on. This method uses sub-atmospheric pressure CVD.
(sub-atmospheric CVD), the principle of which is
The average free path between gas atoms is reduced by lowering the pressure (average mea
By increasing the length of n free-pass and rotating the wafer, the chances of gas atoms contacting the wafer are increased and the film growth becomes uniform. Specifically, when poly Si is grown at 600 to 635 ° C. and a pressure of about 1.0 to 30 torr, the film growth rate becomes 500 to 5000 ° / min. Since the coating does not adhere to the back surface of the wafer supported by the SiC susceptor, the wafer is likely to warp.

It is generally said that when the reaction temperature is as high as 800 ° C. or higher, the use of a cold wall reactor becomes difficult in the following points: (a) It is difficult to keep the temperature of the furnace wall low; Power and cooling water usage will increase dramatically;
(C) Particles are more likely to be generated; (d) The time for the cleaning step for removing the unnecessary adhesion film becomes longer.

In a cold-wall heating furnace, the processing time per wafer is as short as 5 to 10 minutes.
The number of grooves in the carrier of the wafer, which is the means for transporting the wafer, is determined according to the minimum number of wafers required to move to the next step of CVD, for example, cleaning and resist coating, and this number is usually 25. . For example, the processing time for 25 wafers is 125 to 250 minutes.

[0005] In a hot wall type heating furnace, a method of performing LP (low pressure) -CVD on a plurality of semiconductor silicon wafers arranged in parallel in a soaking space formed in a heating furnace having a reaction tube therein is provided. Because of its long history, it has been reported in numerous documents. A typical example of forming a film on a semiconductor silicon wafer by CVD is shown below. (A) Formation of SiO ₂ film by SiH ₄ and O ₂ (400 ° C.
(B) Generation of PSG film by SiH ₄ , PH ₃ and O ₂ (c) Generation of P-doped or non-doped poly Si (580 to 620 ° C.) or a (amorphous) Si by SiH ₄ and Si ₂ H ₆ ( (500 to 530 ° C.) (d) HTO (High) by SiH ₄ and N ₂ O (or NO)
Temperature Oxi-dation) Film formation (800-850)
° C) (e) SiO ₂ film using TEOS and ozone, BPSG
Formation of film (about 650-690 ° C.) (f) Si ₃ N ₄ using NH ₃ and SiH ₄ or SiCl ₂
Generation of film formation of (720~800 ℃) (g) generation of the Ta ₂ O ₅ film using tantalum alkoxide (400~440 ℃) (h) WSi 2 film

Similarly, a method of forming a film on a semiconductor silicon wafer by a direct reaction of a reaction gas has been reported in many documents, and examples thereof are shown below. (I) Conversion of Si into SiON and SiN by reacting single crystal or polycrystalline silicon with NH ₄ , ie, Si
Formation of ON film and SiN film (j) Single crystal or polycrystalline silicon and NO or N ₂ O
SiON film by reacting, reacting SiO ₂ film the Ta ₂ O ₅ film and the generation of the TaN film by reacting the NH ₄ (l) SiO ₂ film and NH ₃ by generating (k) the (g) of SiO
Generation of N film (m) Reaction of Ti film on Si wafer with NH ₃ or N ₂ (n) Generation of TiN film by reaction of TiO ₂ film on Si wafer with NH ₃ or N ₂

FIG. 1 shows a quartz inner tube 2a, a quartz outer tube 2b, and a quartz boat 18 arranged at the upper part of a conventional hot wall type heating furnace, and mechanisms such as heat insulation, support, cooling, sealing, etc. arranged at the lower part. Is not shown. The quartz boats 18 are arranged vertically in a large number of shelves so that about 150 wafers 5 can be processed at one time. The reaction gas is introduced into the inner quartz tube 2a from below, flows upward in the furnace space, flows between the individual semiconductor silicon wafers, and reacts. Thereafter, the reaction gas passes through the annular gap between the inner quartz tube 2a and the outer quartz tube 2b and is exhausted from the gas outlet. In such a hot wall type heating furnace, the heating time is long,
This is advantageous from the viewpoint of alleviating the thermal stress required when manufacturing a miniaturized device on a large-diameter wafer. In order to put wafers into and out of the quartz boat 18 of the hot-wall type heating furnace shown in FIG. 1, it is common to load one wafer at a time or a large number of wafers at once into a fork-shaped groove supporting the wafers.

In a hot wall type heating furnace for performing LP-CVD, about 100 to 150 wafers are formed in 5 to 9 mm.
CV by arranging in the soaking area of 700 to 900 mm in pitch
D is going. Under these conditions, in order to make the thickness of each wafer uniform, the pressure in the furnace is reduced to about 0.3 to 1 torr and the reaction gas is supplied into the furnace at a high speed of about 3 to 7 m / sec or more. . The reaction gas flows around the wafer in the inner quartz tube in a direction perpendicular to the wafer surface, and is then supplied while being caught from the peripheral portion between the wafer surfaces. Under such low pressure conditions, the film growth rate is as slow as 20 to 100 Å / min or less. Note that LP
Another factor affecting the growth rate of the film in CVD is the soaking length, the longer it is, the more likely it is that a difference in the growth rate of the film on the wafer upstream and downstream of the gas flow occurs.
Therefore, with the above soaking length, it is generally necessary to limit the number of processed wafers so that the dispersion of the film thickness is in the range of 1 to 3% for a 6-inch wafer.

In the example of the formation of the polysilicon film according to the above (c), the LP-CVD condition is such that the wafer interval is -5 to 7 m.
m; temperature-625 ° C; SiH ₄ flow rate-200 cc / min;
Wafer-8 inches, 50-150 wafers; pressure -0.6 to
When rr, the film growth rate is 50-80 Å / min. The HTO film according to the above (d) is 800
Under the conditions of 0.3 ° C. and 0.3 to 1.0 torr, the film growth rate is 1
The thickness distribution is 5 to 20 Å / min, and the film thickness distribution is 3 to 6.5% for an 8-inch wafer and 2 to 5% for a 6-inch wafer. These film growth rates are considerably lower than those of a single wafer by lamp heating. Also 15
The total processing time, including temperature rise and fall, is about 1
20-600 minutes. Although the total processing time varies greatly depending on the type and thickness of the formed film, the growth of amorphous silicon (thickness: 1 μm) is an example in which the total processing time is long, ie, 600
More than a minute. As described above, in the CVD method and the direct reaction method using the hot-wall heating furnace, the growth rate of the film is slow.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus capable of high-speed film formation, deviating from the concept of conventional hot wall heating furnace processing.

[0011]

According to a first aspect of the present invention, there is provided a semiconductor device manufacturing apparatus comprising: a heating furnace having a reaction tube therein; a heating furnace having a heating tube provided therein; A reaction unit for forming a film by chemical vapor deposition or a direct reaction on the semiconductor silicon wafer. A semiconductor device manufacturing apparatus comprising: First gas guiding means for guiding to a nearby position, means for injecting substantially all of the reaction gas from the first gas guiding means into the gap between the semiconductor silicon wafers at the near position, and A plate-like substrate provided with support means for supporting the semiconductor silicon wafer from below at intervals, and moving between the semiconductor silicon wafer and the plate-like substrate when the semiconductor silicon wafer is taken in and out of a heating furnace. A semiconductor device manufacturing apparatus, comprising: a wafer loading / unloading member capable of rotating the plate-shaped substrate about an axis perpendicular to the wafer surface; A semiconductor device manufacturing apparatus comprises a heating furnace having a reaction tube therein, and a film formed by chemical vapor deposition or a direct reaction on a semiconductor silicon wafer placed in a soaking space formed in the reaction tube and placed horizontally. A first gas guide means for shutting off the reaction gas from the furnace gas to guide the inside of the furnace to a position near an edge of the semiconductor wafer, Means for injecting the whole amount of the reaction gas from the first gas guide means into the gap between the semiconductor silicon wafers at the above-mentioned position, Means, a lacking portion formed by lacking a part of the supporting means, a driving means for rotating the supporting means about an axis perpendicular to the wafer surface, and a semiconductor wafer taken in and out of the heating furnace. And a wafer loading / unloading member which can be advanced / retracted through said lacking portion under said semiconductor silicon wafer. Hereinafter, the contents of the present invention will be described in more detail. First, the contents common to the first invention and the second invention will be described.

(1) Heating furnace: A so-called hot wall type heating furnace in which a soaking space is formed in the reaction tube inside the reaction tube in which the reaction tube is provided. The reaction tube may be single or double.

(2) Semiconductor silicon wafers: The semiconductor silicon wafers are arranged in parallel so that the surfaces face each other in a soaking space in a furnace. The number of semiconductor silicon wafers (hereinafter, referred to as “wafers”) is, for example, 5, 13, 50 according to the number of wafers to be loaded on a jig for moving the wafers between processes.
Any number of sheets, such as sheets, can be processed. However, about 7
If more than five sheets, the soaking length becomes too long and the film thickness distribution deteriorates, and the processing time becomes longer, so it is preferable to set the upper limit to about 75 sheets. In addition, when the wafer interval is small, the temperature rise and the temperature decrease become slow. Therefore, the interval is set to about 5 mm or more. The upper limit is determined by an appropriate heating furnace soaking length, but is about 100 mm.

(3) Injection and discharge of the reaction gas: In the conventional method, the reaction gas is discharged into the furnace at a high speed at a stroke, and then is wound into the gap between individual wafers from a position where the wafer edge is not specified. The wafer is brought into contact with the entire surface, and then discharged from between the individual wafers. In this method, however, the distribution of the film thickness fluctuates greatly at the upper and lower positions of the wafer. Therefore,
When high-speed growth is attempted by increasing the pressure, the fluctuation of the film thickness distribution becomes larger. Therefore, in the present invention, with respect to the supply of the reaction gas into the wafer gap, substantially all of the reaction gas is sent from a specific position. In other words, the first position for introduction is specified at an arbitrary position around the wafer by using an introduction gas pipe or the like, and the gas flows substantially parallel to the wafer surface from the hole formed in the gas pipe. . This can significantly increase the growth rate. Since the exhaust method on the discharge side does not have as great an effect on the film growth rate as the air supply method on the inlet side, the exhaust method can be carried out through the exhaust holes provided in the upper or lower part of the reaction tube as in the conventional method. This method achieves satisfactory results when the number of wafers is about 25 or less.
Of course, it is also preferable to specify a second location for the exhaust, which is the location where the gas flows opposite the first location. In addition, the second position should face one or more wafer gaps, preferably each wafer gap, when viewed in the vertical direction. The tubes, partition plates, boxes, etc. that define these positions must separate the internal space through which the gas flows and the internal space of the reaction tube, and be in communication with the internal space of the reaction tube only through the discharge holes and the suction holes. is there. Further, the reaction gas is ejected with the pressure in the inlet gas pipe being higher than the pressure in the reaction pipe, for example, about 0.1 to 1 atm, and the reaction gas is sucked by connecting a pump or the like to the end of the exhaust pipe. .

[0015] The "edge" of the wafer edge at which the reaction gas is ejected or sucked is not the upper or lower part of the reaction tube as in the conventional method, but a position extending in the horizontal direction from the gap between the wafers. The distance is such that the inflow / outflow reaction gas in the above does not substantially mix with the inflow / outflow gas in the adjacent wafer gap. The specific value of this distance is determined by giving the wafer gap, gas flow rate and pressure, and using a software solver (Cradle Software STREAM V).
2.9-A 3D thermo-fluid analysis program using the finite element analysis method
You can know by installing and analyzing on 4D / indy). The first and second gas guiding means are means for flowing gas, such as an independent tube, a tube formed by forming a part of the inner wall of the reaction tube as a part of the means, and a box.

Hereinafter, a description will be given of a method mainly for specifying the first and second positions and for feeding and discharging the reaction gas from the tube, respectively. As described above, the reaction gas guided to the vicinity of the individual wafer gap is ejected toward the wafer gap at substantially the same flow rate from the individual ejection holes (first holes), and subsequently between the wafer surfaces. Inflow and spread. In order to promote the spread of the gas at this time, it is preferable that the gap between the ejection hole and the wafer edge is as far as possible. Similarly, the total area of the ejection holes (first holes) and the suction holes (second holes) is preferably equal to or less than the internal cross-sectional area of each tube. In order to make the flow rate of the reaction gas substantially equal to the gap between the individual wafers, the diameter of the first hole is increased in the downstream direction of the gas flow, and the inner diameter of the gas guide tube is increased on the tip side. A method can be adopted. However, in this method, since the dimensional adjustment of the hole diameter and the like and the processing of the hole are complicated, two or more tubes having the same inner diameter and the same hole diameter are reversed in the gas flow direction and up and down in the furnace length direction. It is preferable to arrange them alternately in the direction, or to connect them to one pipe and meander them.

Regarding the shape and structure of the first and second gas guide means, the cross section may be any shape such as circular, rectangular or semicircular. The number of tubes is 1 or 2 or more,
In the case of two tubes, the gas flow can be made uniform for many wafers by reversing the gas flow direction. The number of ejection holes and suction holes is one or two or more for each wafer gap. In the case of two or more ejection holes, it is necessary to separate them so that the reaction gas does not interfere before entering the wafer gap.

(4) Rotation of the wafer: The wafer is rotated around an axis perpendicular to its surface to bring the reaction gas into contact with the entire surface of the wafer to make the film thickness uniform. The rotation speed is preferably 5 to 60 rpm.

According to the apparatus of the present invention characterized by the above (1) to (4), the pressure suitable for high-speed growth can be set to 1 to 40 torr. The measurement position of the gas pressure can be set as close as possible to the furnace in the exhaust pipe as in a conventional hot wall type heating furnace.

The apparatus for manufacturing a semiconductor device according to the first and second aspects of the present invention further includes the following (5-1) and (5-2)
Wafer support jig. (5-1) Jig In the first invention, the jig for holding the wafer has a plate-like substrate fixedly provided with support means such as pins and protrusions for supporting the wafer from below. Since the wafer is supported from below by pins or the like, the wafer is lifted above the plate-like substrate, and a space is formed between the wafer and the wafer loading / unloading jig. The plate-shaped substrate serves as a partition for fixing pins and the like, and for partitioning upper and lower gas flow paths. When the pins are used to support the wafer, the CVD film also adheres to the entire back surface of the wafer, and this has the advantage that the CVD films adhering to both surfaces of the wafer prevent the wafer from warping. If the wafer is supported on the plate-like substrate by the surface contact method, the temperature distribution of the wafer is undesirably large. (5-2) Jig; In the second invention, the jig for holding the wafer includes pins for supporting the wafer at several places from below,
It has an annular body in which projections and the like are arranged in the peripheral direction, and a part of this annular body is omitted so that the wafer loading / unloading jig can advance and retreat. The wafer support jig is taken out of the furnace when loading / unloading the wafer. Thereafter, when loading and unloading the wafer, a part of the annular body is cut out so that the wafer loading and unloading jig can be easily advanced and retracted. Note that, instead of the above-described wafer holding method, the annular jig itself may contact and hold the wafer. Since the peripheral portion of the wafer is supported from below as described above, the central portion occupying most of the area of the wafer is exposed downward. Therefore, the annular wafer holding jig and the wafer itself partition the upper and lower gas passage spaces. A conventional fork-like wafer loading / unloading jig can be used for the wafer supporting jig having the above-described structure, and even with other jigs, the jig advances from the cut portion to below the wafer surface. Any jig can be used as long as it can retreat.

When the wafer is heated and heated, the annular body of the wafer supporting jig has an effect of reducing the temperature difference between the central portion and the peripheral portion of the wafer. It is preferable that the projections serving as contact portions with the wafer are arranged in the circumferential direction so as to stably hold the wafer, and are evenly arranged in as small a number as possible. These projections can project directly from the annulus, but they can also be secured to the tip of a bar that extends inward from the annulus. Further, a reinforcing ring for connecting the tips of the rods can be provided.

In order to make the gas flow easier to spread, it is better to keep the ejection holes (first holes) as far away from the wafer as possible. However, the gas flow directed between adjacent upper and lower wafers becomes easier to mix. In order to avoid this, a plate-like substrate or a support means for restricting the gas from flowing into the gap between the upper and lower wafers must be effectively operated. Therefore,
The plate / supporting means should be the first as far as possible without impeding rotation.
It is preferable to approach a tube body or a reaction tube wall in which the second hole is formed. Further, a fin for narrowing the gap between the reaction tube wall and the plate-like substrate may be fixed to the former.

In the case of lower exhaust, the following means can be employed in the present invention in order to equalize the suction gas flow rate depending on the vertical position of the wafer. (A) The inside of the second gas guide means is partitioned into at least two parallel flow paths in the wafer arrangement area, the cross-sectional area of the flow path having a gas inlet on the upper side of the furnace is relatively large, and The cross-sectional area of the flow path having the side gas outlet is relatively reduced. In FIG. 2 described later, the desired effect is achieved by adjusting the width of the flow path. (B) A second hole common to the entire wafer gap or several groups is provided, and the width of the second hole is reduced toward the lower side. (C) sub-holes are provided in a strip shape on both sides of a second hole having the same width common to the entire wafer gap;
By adjusting the position and length of the sub-hole, the upper second
Make the hole cross-sectional area larger than the lower side. In the case of upper exhaust, the flow path (hole) size relationship is determined by the above (a), (b),
Reverse to (c). Hereinafter, the present invention will be described in more detail with reference to examples.

[0024]

FIG. 2 shows an embodiment of the first and second inventions relating to a lower exhaust system, which basically comprises a heating furnace 1 and a wafer elevating mechanism 30. FIG. Normal S
Reaction tubes of iC, quartz, etc. (hereinafter referred to as "quartz reaction tubes")
Numeral 2 is a tube body whose upper end is closed and whose lower end is open. The tube body is provided so as to surround the upper periphery thereof, and a heater 3 for creating a soaking space is fixed to a furnace body 4 made of a heat insulating material. The quartz reaction tube 2 is air-tightly and detachably fixed to a furnace bottom structure 37 at a lower end portion bent in an L shape, and is supported by a support 6. In the illustrated state, the wafer 5 has been raised to the upper limit position by the wafer lifting mechanism 30. The wafers 5 having a diameter of 8 to 12 inches, which are stacked in multiple stages and spaced apart from each other by about 5 mm or more, are heated to a predetermined temperature by the heater 3. 5 'is a dummy wafer. The support members for the wafer 5 and the dummy wafer 5 'are not shown.

The wafer elevating mechanism 30 is configured to move the lower member 3
The wafer 5 is mounted on a rotating shaft 32 on which a separator 31 having a heat insulating function for preventing heat from the heat sink 3, 34, etc. is fixed.
Are omitted from the illustration of the detailed structure of the jig in which are arranged vertically. A magnet or coil 33 is attached to the lower end of a rotating shaft 32 for rotating this jig, and another magnet or coil 34 that exerts a rotational force on the magnet or coil 33 is provided vertically movable, so that the wafer elevating mechanism 30 Is raised and lowered, and the rotating shaft 32 is rotated. A table 3 that supports the magnet 34 and the like to perform such ascent and descent.
The rod 36 screwed with 5 is rotated by the driving device 40a.

A tube 42 for guiding the rotation shaft 32 up and down.
And a furnace bottom structure 37 integrally connected to the bottom of the heating furnace above it is hermetically fixed at the position shown in the drawing during processing of the wafer 5, and is rotatably connected to the support 6 before and after the processing. When the rod 38 is rotated by the driving device 40b,
A connecting portion 39 screwed to the rod 38 and fixed to the furnace bottom structure 37 is moved up and down along the rod 38. Accordingly, the furnace bottom is opened or closed. A small amount of purge gas such as N2 gas can be fed into the furnace from the inlet 42a through the inside of the tube 42 that guides the rotary shaft 32 up and down. The rod 36, the driving device 40a, and the connecting portion 41
5 is a mechanism for raising and lowering the table 3. When the driving device 40a rotates the rod 36,
5 slides up and down by sliding with the tube 42, and the vertical position of the rotary shaft 32 is adjusted.

In FIG. 2, reference numeral 10 designates a flow path for flowing a gas by using a part of the reaction tube as a double tube in order to distribute and eject the reaction gas supplied from the mother tube 12 between the individual wafers 5. This is the first gas guide means. Reference numeral 20 denotes second gas guide means for sucking a reaction gas from between the individual wafers 5. Reference numeral 22 denotes an exhaust pipe communicating with the second gas guide means 20. The exhaust pipe 22 sucks a reaction gas by a pump and is provided with a pressure measuring device 41. Since the reaction gas ejection holes and the reaction gas suction holes described later are positioned so as to face the gaps between the vertically arranged wafers 5, the reaction gas is directly ejected into the wafer gaps and exhausted directly from the gaps. A laminar flow state can be realized in the inner space. That is, when a part of the reaction gas flow flowing upward or downward in the furnace space as in the related art is diverted to the wafer gap, the gas flow stays between the wafers, and it is difficult to control the individual gaps. According to the invention, however, such stagnation is avoided and control in individual gaps is also possible. In the lower exhaust system, since the pipes are concentrated at the lower part of the furnace, this problem can be avoided by employing the upper exhaust system described in paragraph 0037 (2) described later.

As shown in FIG. 3 (a view taken along the line BB in FIG. 2), the second gas guide means 20 has a wide intake hole 21 (second
Of the same number as the wafer gap. In order to suck the reaction gas layer spread over the entire surface of the wafer at the wafer gap without mixing between the upper and lower layers, the suction hole 21 is preferably as wide as possible, and the preferable thickness is 0.5.
１．５1.5 mm.

FIG. 4 is a sectional view taken along the line AA. The first gas guide means 10 is constituted by storing three tubes 10a, 10b and 10c branched from a common mother tube 12 in a portion obtained by partially deforming a quartz reaction tube into a bag shape. That is, in the case of CVD using three kinds of gases, when the reaction gas is guided by one tube, the reaction gas reacts before jetting, so that the first gas guiding means is formed by the three tubes. . It is preferable that the total area of the ejection holes of the first gas guide means 10 is smaller than the cross-sectional area of the mother pipe. Further, the inner wall of the quartz reaction tube and the tube 10
Since the curve connecting the insides of a, b, and c is circular, the wafer 5
A circular annular gap 47 is left between the outer peripheral edge and the outer peripheral edge. The gap 47 is formed in the substrate 18 (FIG. 5) or the annular body 18 (FIG. 6,
7), the reaction gas is prevented from rising or flowing downward, and an ideal laminar flow state can be realized. The second gas guide means 20 is located in a direction opposite to the tube 10 of the first gas guide means about the center axis of the wafer. Therefore, for example, the tube 10a,
A straight line connecting the center of the wafer and the second gas guiding means 20 can be drawn. The second gas guiding means 20 is a box connecting the outer arc-shaped portion 20a, the inner wall 2a of the reaction tube having the suction hole 21 formed vertically and the side portion 20c (see FIG. 2),
By guiding the reaction gas through the internal flow path 20b, mixing with the gas in the furnace and diffusion into the furnace are avoided. FIG.
As shown in (2), two partition plates 20d are provided in the second gas guide means 20 along the gas flow path 20b so that the suction flow rates from the upper and lower wafers are substantially equal. Therefore, the flow distance of the reaction gas from the upper wafer becomes longer and the flow resistance becomes larger. Therefore, the flow resistance becomes smaller by increasing the cross-sectional area.

FIG. 5 shows an embodiment of the apparatus of the first invention, and shows a supporting structure of the wafer 5 which is omitted in the apparatus of FIG. That is, four or six pins 19 are provided at equal angles on a substrate 18 made of a quartz disk or the like to support the wafer 5 from below. In this supporting method, since the wafer 5 is not supported at the center, it tends to be warped.
Even at a heating temperature of 900 ° C. or less, even a 12-inch wafer does not cause warping to a problem. When the wafer elevating mechanism 30 is lowered and the wafer 5 is moved out of the furnace, the height of the pin 19 is set between the fork 2 and the substrate 18.
6 is a value that allows entry and exit. Further, the gap between the substrate 18 and the inner wall of the reaction tube is a narrow gap in which the flow of the reaction gas ejected in parallel to the upper surface of each wafer 5 does not easily flow to the wafers above and below the wafer. Reference numeral 27 denotes a stopper for preventing the wafer from shifting. The whole substrate 18 is connected to two upright supports 45, and the upright supports 45 are connected to the rotation driving means of the wafer via the rotary shaft 32 (FIG. 2). Reference numeral 17 denotes a gas nozzle (first hole) formed of a first hole formed in a wall of the first gas guiding means 10. The reaction gas ejected from the gas nozzle 17 flows toward the second gas guide means 20 as shown by the arrow.

FIGS. 6 and 7 show an embodiment of the apparatus of the second invention, and show a support structure of the wafer 5 which is omitted in the apparatus of FIG. 6 is a view taken in the direction of the arrow in FIG. 7, and FIG. 7 is a view taken in the direction of the arrow in FIG. 6 (however, the wafer is not shown). A notch through which the wafer loading / unloading member enters and exits is formed in a part of the annular plate 28 fixed to a pair of upright columns 45 provided at positions 180 ° opposite to each other in the diameter direction. The annular plate 28 has a stepped structure in which the outside is thick and the inside is thin, and the pins 29a projecting upward from the inside support the wafer 5 in a point contact manner. The annular plate 28 and the wafer 5 serve as upper and lower partition plates, and the reaction gas ejected from any one of the first holes 17 is supplied to the wafer 5.
Prevent it from escaping up and down. 27, 28, 29
And 45 are integrally carried out of the furnace, and the fork 2 shown in phantom lines in FIG.
6 takes in and out of the wafer. The reaction gas flowing from the jet gas nozzle 17 comes into contact with the back surface of the wafer 5 and forms a poly-Si film or the like also on the lower surface of the wafer.

The contrasting features of the jig of FIG. 5 and the jigs of FIGS. 6 and 7 are as follows. (1) The jig of FIG. 5 is suitable for the growth of a film having a strict requirement for the film thickness distribution, and is suitable for the growth of a film whose film thickness tends to fluctuate, such as an HTO film generated by SiH ₄ and NH _3. I have.
The jigs in FIGS. 6 and 7 have cutouts in the annular plate 28,
The film thickness distribution tends to be large. Therefore, the jigs shown in FIGS. 6 and 7 are suitable for growing a film having a gradual demand for the film thickness distribution or for growing a film whose film thickness is unlikely to fluctuate, such as Si3N4, on a large number of wafers.

FIG. 8 schematically shows a reaction gas flow ejected from the first gas guide means. That is, the fan-shaped pattern is deformed as the reactant gas flow is slightly bent in the rotation direction of the wafer (not shown), and the gas flow is diffused somewhat in the width direction. I have. As shown in the figure, the reaction gas flows on the wafer surface by jetting and suctioning, not by entrainment. A different type of reaction gas such as silane, phosphine, diborane, or the like, or the same type of reaction gas can be flowed from the tubes 10a, 10b, and 10c of the first gas guide means.
The pipe 1 is set so that the jet gas flow has an angle θ of 30 to 40 °.
It is preferable to eject from 0a, 10b, 10c. Since the concentration of the reaction gas in contact with the wafer 5 is locally reduced, the wafer 5 is rotated to rotate the wafer 5.
The film growth on the surface is made uniform.

Returning to FIG. 2 again, reference numeral 15 denotes a purge gas introduction pipe, which is used to supply a small amount of a non-reactive gas such as N 2 or an inert gas such as Ar to flow a small amount of a reactive gas into the lower part of the furnace. This prevents particles from being generated in the lower part of the furnace. If a large amount of the purge gas blows up from the gap 47 (FIG. 4), the flow of the above-described reaction gas is disturbed. Therefore, the purge amount is made extremely small and / or the exhaust gas is exhausted from a pipe provided at the position 15 '. There is a need to.

FIG. 9 shows first gas guide means according to one embodiment. The gas supply source may be common to each of these parts, or may be individual for each part. Specifically, as shown in FIG. 9 (illustration of the ejection holes is omitted), the first
The gas guide means 10 branches the mother pipe 12 into two branches, one branch part 10a is extended upward, the other branch part 10b is temporarily extended upward and then turned 180 ° to extend downward ( 10b ₍₁₎ ), the upwardly extending portion 10a and the downwardly extending portion (10b ₍₁₎ ) have an outlet 11 for reactant gas.
Can be formed by the number of wafer intervals. If the reactant gas flows out only from the upward extension 10a, the gas flow distribution increases in the lower wafer, but by providing the downward extension 10b ₍₁₎ , such a gas flow distribution is averaged. be able to. Further, when the total area of the ejection holes is substantially equal to or less than the sectional area of the mother pipe, more preferable results can be obtained.

Next, a more preferred embodiment of the apparatus according to the present invention will be described. The flow rate of the gas flowing from the ejection hole of the first gas guide means, which usually consists of a single pipe, decreases at the tip. To avoid this, the diameter of the ejection hole may be made larger or the inner diameter of the pipe may be made smaller at the tip, but accurate flow control is difficult to achieve. Therefore, it is preferable to equalize the gas flow rates from all the ejection holes by including a part for flowing the gas upward and a part for flowing the gas downward in the same gas guide means and arranging these parts in parallel. FIG. 10 shows the first gas guide means 10 which is more compact than that of FIG. 9, and shows a partition plate 10 in two flow paths flowing in one tube in parallel and opposite directions.
The end of the downward flow path is stopped at p. Since the first holes 17 having the same hole diameter are formed in each of these two flow paths, the gas flow rates are averaged for the upper and lower wafers.

Various known techniques of the apparatus of the present invention described above can be additionally applied. This includes: (A) Plasma cleaning known in Japanese Patent No. 2025683 of the present applicant is performed. In this case, it is preferable that all members exposed to the plasma inside the furnace body are made of quartz. (B) A cold-wall furnace is combined with a hot wool furnace (that is, a heating furnace according to the present invention) as is known from the applicant's utility model registration No. 30377794. (C) The entire lower surface of the wafer is supported on a SiC plate having good thermal conductivity, and a film is grown on the upper surface. (2) Evacuation by the second gas guide means can be performed after guiding the gas to the upper part of the heating furnace (Japanese Patent Laid-Open No. 11-3).
No. 859 / see FIG. 3). The exhaust portion is also located in the soaking space in the furnace or set at a temperature substantially equal to the reaction temperature so that the reaction film adhered to the exhaust portion tube wall is made the same as that of the reaction portion. Further, a trap type gas flow path in which the exhaust gas meanders can be formed above the top of the quartz reaction tube (Japanese Patent Application Laid-Open No. 6-188209). The generation of particles can be suppressed by such an exhaust method.

In the device of the present invention, the C
By performing VD growth, it is possible to grow at a growth rate of 300 to 2000 ° / min and a film thickness distribution within 2 to 5%. Further, when HTO CVD growth is performed, 30 to 150 °
/ Min and a film thickness distribution of 1 inch for an 8-inch wafer
Can grow at ~ 4%.

[0039]

As described above, the present invention relates to
Alternatively, in a direct reaction process, a high-speed film formation process is performed on a wafer, and the uniformity of the film thickness is not inferior to the conventional method.

[Brief description of the drawings]

FIG. 1 is a partial perspective view of a conventional hot wall heating furnace.

FIG. 2 is a cross-sectional view of a heating furnace according to one embodiment for carrying out the method of the present invention.

FIG. 3 is a sectional view taken along the line BB of FIG. 2;

FIG. 4 is a sectional view taken along line AA in FIG.

FIG. 5 is a view showing a wafer support section of the first invention;
It is the elements on larger scale of FIG.

FIG. 6 is a view showing a wafer support portion of the second invention;
FIG. 8 is a partial enlarged view of FIG. 2, and is a cross-sectional view along an arrow in FIG. 7.

FIG. 7 is a view showing a wafer support portion of the second invention;
FIG. 7 is a plan view along an arrow in FIG. 6.

FIG. 8 is a plan view schematically showing a reaction gas flow.

FIG. 9 is a drawing showing an embodiment of the first gas guide means.

FIG. 10 is a drawing showing another embodiment of the first gas guiding means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heating furnace 2 Quartz reaction tube 3 Heater 4 Furnace body 5 Wafer 7 Wafer support jig 10 First tube body 12 Main pipe 15 Purge gas introduction nozzle 17 Gas nozzle (first hole) 18 Boat 19 Pin 20 Second gas Guide means 21 Intake hole (second hole) 22 Exhaust pipe 24 Post 26 Fork 27 Stopper 28 Annular plate 30 Wafer elevating device 31 Separator 32 Rotating shaft 33 Magnet or coil 34 Magnet or coil 35 Base 36 Rod 37 Hearth structure Body 38 Rod 39 Connecting part 40 Driving means 41 Pressure gauge 42 Tubular body 45 Upright support 47 Gap

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K030 AA06 AA13 BA29 BA40 BA44 BB03 CA04 CA12 EA06 GA02 GA06 GA12 KA04 5F045 AB03 AF03 BB03 BB09 DP19 DQ05 EE20 EF03 EF20 EG05 EM08 EM10

Claims (7)

[Claims] 1. A heating furnace having a reaction tube therein, and a film formed by chemical vapor deposition or a direct reaction on a semiconductor silicon wafer positioned in a soaking space formed in the reaction tube and placed horizontally. And a first gas guide means for shutting off the reaction gas from the furnace gas and guiding the inside of the furnace to a position near the edge of the semiconductor silicon wafer. Means for injecting the reaction gas from the first gas guide means into the gap between the semiconductor silicon wafers at the above-mentioned position, a plate-like substrate provided with support means for supporting the semiconductor silicon wafer from below at intervals of 5 mm or more; Drive means for rotating the plate-like substrate about an axis perpendicular to the plane, and the semiconductor silicon wafer and the plate when the semiconductor silicon wafer is taken in and out of the heating furnace. Apparatus for manufacturing a semiconductor device characterized by comprising a retractable wafer instrumentation and out member between the substrates. 2. A heating furnace having a reaction tube therein, and a film formed by chemical vapor deposition or a direct reaction on a semiconductor silicon wafer positioned in a soaking space formed in the reaction tube and placed horizontally. And a first gas guide means for shutting off the reaction gas from the furnace gas and guiding the inside of the furnace to a position near the edge of the semiconductor silicon wafer. Means for injecting the reaction gas from the first gas guide means into the gap between the semiconductor silicon wafers at the above-mentioned position, supporting means for supporting the semiconductor silicon wafer at the peripheral edge thereof at a distance of 5 mm or more from below, and this supporting means A driving means for rotating the supporting means about an axis perpendicular to the wafer surface; and a driving means for driving the semiconductor silicon wafer out of the heating furnace. Apparatus for manufacturing a semiconductor device according to claim through the lack portion below the semiconductor silicon wafer can further comprise a retractable wafer instrumentation and out member when placed. 3. The apparatus for manufacturing a semiconductor device according to claim 2, wherein said wafer supporting means includes a projection fixed on a main body thereof and supporting a semiconductor silicon wafer. 4. The manufacturing method of a semiconductor device according to claim 1, wherein a purge gas introduction hole made of a non-reactive gas or an inert gas is provided in a lower portion of said reaction tube. apparatus. 5. A reaction gas flowing out from between the semiconductor silicon wafers is sucked through a second hole formed in a wall surface facing the gap between the semiconductor silicon wafers, cut off from a gas in the furnace, and reaches outside the furnace. 5. The semiconductor device according to claim 1, further comprising a second gas guiding means for guiding, and an exhaust means connected to the second gas guiding means. apparatus. 6. The semiconductor device manufacturing apparatus according to claim 5, wherein said second holes are provided for each of said semiconductor silicon wafer gaps. 7. An apparatus for manufacturing a semiconductor device according to claim 5, wherein one of said second holes is provided for several of said semiconductor silicon wafer gaps.