JP4083331B2 - Semiconductor device manufacturing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present inventionMulti-batch batch process of semiconductor silicon wafers by chemical vapor deposition (CVD) or direct reaction with reaction gasDoIt is an improvement of the method and relates to a semiconductor device manufacturing apparatus that increases the growth rate of these films.
[0002]
[Prior art]
As a method for performing uniform CVD on a 6-8 inch large-diameter silicon wafer, a single semiconductor wafer placed horizontally on a SiC susceptor is rotated, and the reaction gas is horizontally applied to the wafer surface while heating the lamp. A method for forming a film by pouring is known. The advantage of this method is that it is a cold wall system in which the reactor wall is cooled, so SiH_Four It is difficult for the reaction gas to adhere to the furnace wall; there is relatively little generation of particles; rapid heating is easy. This method is called sub-atmospheric CVD, and its principle is to lower the pressure and increase the mean mean free-pass between gas atoms and rotate the wafer. This increases the chances of gas atoms coming into contact with the wafer and makes film growth uniform. Specifically, the film growth rate becomes 500 to 5000 Å / min when poly Si is grown at 600 to 635 ° C. and a pressure of about 10 to 80 torr.
[0003]
In general, it is said that the use of a cold wall reactor becomes difficult when the reaction temperature is higher than 800 ° C. in the following points: (b) It is difficult to keep the temperature of the furnace wall low; (b) Power and cooling The amount of water used increases drastically; (c) particles are likely to be generated.
[0004]
In a cold wall type heating furnace, the processing time per wafer is 5 to 10 minutes, but the number of wafers is adjusted to the minimum number required for the next CVD process, for example, cleaning and resist coating process. The number of grooves of the carrier of the wafer, which is the transport means, is determined, 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 furnace, LP (low pressure) -CVD method has been used for a long time for semiconductor silicon wafers arranged in parallel with each other in a soaking space formed in a furnace equipped with a reaction tube. Has been reported in many literatures. A typical example of forming a film on a semiconductor silicon wafer by CVD is shown below.
(A) SiH_Four And O₂ SiO by₂ Film formation (about 400 ° C)
(B) SiH_Four , PH_Three And O₂ Of PSG film by plasma
(C) SiH_Four , Si₂ H₆ Formation of P-doped or non-doped poly-Si (580-620 ° C.) or a (amorphous) Si (500-530 ° C.)
(D) SiH_Four And N₂ Generation of HTO (High Temperature Oxi-dation) film by O (or NO) (800-850 ° C)
(E) SiO using TEOS and ozone₂ Film and BPSG film formation (about 650-690 ° C)
(F) NH_Three And SiH_Four Or SiCl₂ Si using_Three N_Four Film formation (720-800 ° C)
(G) Ta using tantalum alkoxide₂ O_Five Film formation (400-440 ° C)
(H) WSi₂ Membrane generation
[0006]
Similarly, methods for forming a film on a semiconductor silicon wafer by direct reaction of a reactive gas have been reported in many literatures, and examples of these are shown below.
(I) Single crystal or polycrystalline silicon and NH_Four Of Si to SiON, SiN, that is, generation of SiON film and SiN film
(J) Monocrystalline or polycrystalline silicon and NO or N₂ SiON film by reacting O, SiO₂ Membrane generation
(K) Ta according to (g) above₂ O_Five Membrane and NH_Four Of TaN film by reacting
(L) SiO₂ Membrane and NH_Three Of SiON film by reacting
(M) Ti film and NH on Si wafer_Three Or N₂ Reaction of
(N) TiO on Si wafer₂ Membrane and NH_Three Or N₂ Of TiN film by reaction
[0007]
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 the mechanisms such as heat insulation, support, cooling, and sealing arranged at the lower part are shown in the figure. Omitted. Quartz boats 18 are vertically arranged in a shelf shape so that about 150 wafers can be processed at a time. The reaction gas is introduced into the quartz inner tube 2a from below, flows upward in the furnace space, and flows into and reacts between individual semiconductor silicon wafers. Thereafter, the reaction gas passes through the annular gap between the quartz inner tube 2a and the quartz outer tube 2b and is exhausted from the gas discharge port.
In such a hot wall type furnace, the heating time is long, but it is advantageous from the viewpoint of alleviating thermal stress required when manufacturing a miniaturized device on a large-diameter wafer.
In order to load / unload wafers into / from the quartz boat 18 of the hot wall type heating furnace of FIG. 1, it is common to load one or more wafers into a fork-shaped groove that supports the wafers.
[0008]
In a hot wall type furnace that performs LP-CVD, about 100 to 150 wafers are placed in a soaking area of 700 to 900 mm at a pitch of 5 to 9 mm, and CVD is performed. In order to make the film thickness uniform on each wafer under these conditions, the pressure in the furnace is set to a low pressure of 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 / second or more. . The reaction gas is flowed around the wafer in a direction perpendicular to the wafer surface in the inner quartz tube, and then supplied while being wound from the periphery between the wafer surfaces. Under such low pressure conditions, the growth rate of the film is as low as 20 to 100 angstroms / minute or less. In addition, as another factor affecting the film growth rate in LP-CVD, there is a soaking length. If this lengthens, a difference in film growth rate on the wafer upstream and downstream of the gas flow tends to occur. Therefore, it is generally necessary to limit the number of processed wafers so that the film thickness dispersion is within a range of 1 to 3% in the case of a 6-inch wafer with the above-described uniform heat length.
[0009]
In the example of the polysilicon film generation according to the above (c), the LP-CVD conditions are as follows: the wafer interval is −5 to 7 mm; the temperature is −625 ° C .;_Four With a flow rate of -200 cc / min; wafer-8 inches, 50-150 sheets; pressure -0.6 torr, the film growth rate is 50-80 angstroms / min.
The HTO film according to (d) above has a film growth rate of 15 to 20 mm / min under the conditions of 800 ° C. and 0.3 to 1.0 torr, the film thickness distribution is 3 to 6.5% for an 8-inch wafer, and a 6-inch wafer. 2 to 5%.
These film growth rates are considerably lower than in the case of a single wafer by lamp heating. Further, the total processing time including temperature increase and temperature decrease in the case of processing 150 sheets is about 120 to 600 minutes. Although the total processing time varies greatly depending on the type and film thickness of the generated film, the growth of amorphous silicon (thickness 1 μm) is an example in which the total processing time is long, that is, 600 minutes or more.
As described above, in the CVD method and the direct reaction method using a hot wall type heating furnace, the growth rate of the film is slow. Therefore, productivity increases by processing as many as 150 sheets.
[0010]
[Problems to be solved by the invention]
The present invention is based on the concept of conventional hot wall furnace processing.
Enables high-speed depositionapparatusWith the purpose of providingTo do.
[0011]
    A semiconductor device manufacturing apparatus according to the present invention includes a heating furnace having a reaction tube and a semiconductor silicon wafer positioned in a soaking space formed in the reaction tube and placed horizontally.Using reactive gasIn a semiconductor device manufacturing apparatus comprising a reaction part that forms a film by chemical vapor deposition or direct reaction,Five ~ 100mmA wafer support jig for supporting two or more semiconductor silicon wafers set one by one, driving means for rotating the semiconductor silicon wafer around an axis orthogonal to the wafer surface, and the reaction gas as a furnace gas Shut offheatingSemiconductor inside the furnacesiliconFirst gas guiding means for guiding the wafer to a position near the edge of the wafer, and substantially the entire amount of the reaction gas from the first gas guiding means.EdgeMeans for injecting into the gap between the semiconductor silicon wafers in the vicinity, wherein the wafer support jig is obtained by cutting out one plate leaving the carrying part, and / or the outer ring part and the inner ring part And a third gas guide that restricts diversion from each hole of the first gas guide means toward the gap between the semiconductor silicon wafers facing the hole. Further comprising means.
    Further preferably, (1) facing the semiconductor silicon wafer gapWallThe reaction gas that has flowed out between the semiconductor silicon wafers is sucked through the second hole formed in the substrate, and cut off from the furnace gas.heating furnaceAnd further comprising a second gas guiding means for guiding to the outside and an exhaust means communicating with the second gas guiding means. (2) To each hole of the second gas guiding means, And further comprising a fourth gas guiding means for restricting mixing of the gas flow from the upper and lower wafer gaps with the reaction gas flow discharged from the gap between the facing semiconductor silicon wafers, and (3) second gas Inside the gas guiding meansSemiconductor siliconPartitioning into at least two parallel channels in the wafer array region;heating furnaceLocated aboveSemiconductor siliconThe cross-sectional area of the flow path communicating with the wafer is relatively small.
[0012]
(1) Heating furnace: A so-called hot wall type heating furnace in which a soaking space is formed in the reaction tube in the heating furnace equipped with the reaction tube is used. The reaction tube may be single or double.
[0013]
(2) Semiconductor silicon wafers: arranged in parallel so that the faces face each other in a soaking space in the furnace. The number of semiconductor silicon wafers (hereinafter referred to as “wafers”) can be any number such as 5, 13, 50, etc., depending on the number of wafers loaded on a jig that moves the wafer between processes. Can do. However, if it exceeds about 75 sheets, the soaking length becomes too long and the film thickness distribution deteriorates, and in addition, the processing time becomes long, so it is preferable to set about 75 sheets as the upper limit. Also, if the wafer interval is narrow, the temperature rise and fall will be slow.5mmThe above interval. The upper limit is determined by the appropriate heating furnace soaking length.100mmIt is.
[0014]
(3) Feeding and discharging of reaction gas: In the conventional method, the reaction gas is discharged into the furnace at a high speed, and then wound into individual wafer gaps from an unspecified position of the wafer edge. In this method, the film thickness distribution varies greatly between the upper and lower positions of the wafer. Therefore, if high-speed growth is attempted by increasing the pressure, the variation in the film thickness distribution becomes even greater. Therefore, in the present invention, with respect to the delivery of the reaction gas into the wafer gap, substantially all of the reaction gas is performed from a specific position. That is, the first position for infeed is specified at an arbitrary position around the wafer by using an infeed gas pipe or the like, and gas is caused to flow in parallel on the wafer surface from the hole formed in the gas pipe. Thereby, the growth rate can be remarkably increased. Since the exhaust method on the discharge side does not affect the film growth rate as much as the air supply method on the input side, the exhaust method can be performed from the exhaust hole provided in the upper part or the lower part of the reaction tube as in the conventional method. This method achieves sufficient results when the number of wafers is about 25 or less. Of course, it is also preferable to specify the second position for discharge, which is the position where the gas flows opposite the first position. Further, the first position and the second position need to face one or more wafer gaps, preferably each wafer gap when viewed in the vertical direction. The pipes, partition plates, boxes, etc. that define these positions need to separate the internal space through which the gas flows from the reaction tube space, and communicate with the reaction tube space only by the discharge hole and the suction hole. is there. Furthermore, the reaction gas has a pressure in the inlet gas pipe higher than that in the reaction pipe, for example, 1 atm, and is ejected, and a pump or the like is connected to the tip of the exhaust pipe to suck the reaction gas.
[0015]
The wafer edge "near" where the reaction gas is ejected or sucked is not the upper or lower part of the reaction tube as in the conventional method, but is a position extending in the horizontal direction from the gap between the wafers. The distance is such that the outflow reaction gas does not substantially mix with the inflow / outflow gas of the adjacent wafer gap. The specific value of this distance is determined by the software solver (cradle software STREAM V2.9-3D thermal fluid analysis program using finite element analysis method) given the wafer gap, gas flow rate and pressure. ) Installed on a computer (SiRS Graphic IRS 4D / indy) and analyzed.
The first and second gas guiding means are means for flowing gas such as independent pipes, pipes formed with a part of the inner wall of the reaction tube as part of the means, and a box.
[0016]
In the following, a method of mainly specifying the first and second positions and sending and discharging the reaction gas will be described.
As described above, the reaction gas introduced to the vicinity of each wafer gap is ejected from the individual ejection holes (first holes) toward the wafer gap at a substantially equal flow rate, and subsequently between the wafer surfaces. Inflow and spread. In order to promote the gas spread 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 hole (first hole) and the suction hole (second hole) is preferably equal to or smaller than the internal cross-sectional area of each pipe.
In order to make the flow rate of the reaction gas substantially equal to the gap between individual wafers, the diameter of the first hole is increased in the downstream direction of the gas flow, the inner diameter of the gas guide tube is increased on the tip side, etc. The method can be adopted. However, in this method, since adjustment of dimensions such as the hole diameter is complicated, two or more tubes having opposite gas flow directions are arranged alternately in the vertical direction in the length direction of the furnace, or these It is preferable to connect a single tube to meander.
[0017]
Regarding the shape and structure of the first and second gas guiding means, the cross section may be any shape such as a circle, a short shape, and a semicircle. The number of tube bodies is 1 or 2 or more. In the case of two tube bodies, the gas flow rate for many wafers can be made uniform by reversing the gas flow direction. The number of ejection holes and suction holes is one or more for each wafer gap. In the case of two or more ejection holes, it is necessary to separate the reaction gas so as not to cause interference before entering the gap between the wafers.The present inventionIn this case, if the wafer is supported locally from below by protrusions such as pins, and the film is formed on the unsupported lower surface (the surface on which the semiconductor device is not manufactured), the distortion of the upper and lower films will be warped, especially in the case of thick film growth LessDoThere are advantages. Specifically, in the case of a nitride film, 500 mm or more, SiO₂In the case of a film, it is 5000 mm or more.
[0018]
(4) Rotating the wafer The wafer is rotated around an axis perpendicular to the surface thereof to bring the reactive 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.
[0019]
It is characterized by (1) to (4) aboveThe present inventionAccording to the pressure suitable for high-speed growth, 1 ~ 40torr can be set. The measurement position of the gas pressure can be set as close as possible to the furnace in the exhaust pipe as in the conventional hot wall heating furnace.
[0020]
The present inventionIn (2), in order to perform high-speed CVD growth on a large number of wafers, (a) increase the wafer gap; (b) rotate the wafer: (c) a reaction gas entrainment method from the edge of the wafer gap by the conventional method. Is specified, and the method for sending and discharging reaction gases is specified. The semiconductor device manufacturing apparatus according to the present invention employs the above (a), (b), and (c), further employs the following (5) jig, and in addition, reacts the reaction gas as in (6) below. The inbound and outbound structure is specified.
[0021]
(5) Jig; The jig for holding the wafer is not manufactured by joining the parts by welding or the like as in the prior art.₂ A single plate is cut by an arbitrary method such as laser cutting, punching, or etching. In welding or the like, when the jig is assembled by a method of joining the parts, the flatness of the jig deteriorates due to thermal strain, but the flatness is excellent in the method of cutting the plate. Instead of this method or in combination with this method, a wafer support jig is used in which the carrying part is composed of an outer ring part, an inner ring part, and a connecting part connecting them. By supporting the wafer from the inside and outside by these two annular portions, the warpage of the wafer can be reduced. In a space other than the annular portion and the connecting portion, the film grows also on the lower side of the wafer, so that the film grows on the upper and lower surfaces of the wafer, resulting in less warpage of the wafer. Furthermore, in the case of a large-diameter 12-inch wafer, the height of all the protrusions can be made to be uniform when the wafer supporting protrusions are bonded to the supporting portion by a diffusion bonding method or the like.
[0022]
(6) Reaction gas delivery and discharge structure:FirstAdopt gas guiding means. More preferably, the second gas guiding means is also employed. In order to make the gas flow easier to spread, it is better to keep the ejection holes (first holes) away from the wafer as much as possible, but this makes it easier to mix the gas flow toward the upper and lower adjacent wafers. In order to avoid this, the third gas guiding means for restricting the flow of the reaction gas from the first hole portion to the gap between the wafers facing the hole portion to the upper and lower wafer gaps is provided.Provide. First 2The reaction gas flow flowing from the gap between the wafers facing the hole is restricted from flowing into the upper and lower wafer gaps.4thGas guidance meansIt is preferable to provide it.The third and fourth gas guiding means are partition plates or the like that divide the space between the wafer and the first and second gas guiding means into gas flow paths, and may be separate or integrated.
[0023]
If a conventional fork-shaped wafer loading / unloading jig is used for the wafer support jig having the above-described structure, the wafer cannot be moved in and out because it abuts against the annular portion to prevent the forward movement. Therefore, in the present invention, a heating furnace equipped with a reaction tube, a reaction part that is located in a soaking space formed in the reaction tube, and grows a film on the wafer by chemical vapor deposition or by direct reaction; In a semiconductor device manufacturing apparatus comprising: a wafer supporting jig for holding a wafer with a gap between each other; a wafer is lifted from the wafer supporting jig; And a function of delivering the wafer to and from the lifting means.
[0024]
The partition inside the second gas guiding means according to the embodiment of the apparatus according to the present invention is configured such that the inside of the second gas guiding means is partitioned into at least two parallel flow paths in the wafer arrangement region, and the gas is disposed above the furnace. By making the cross-sectional area of the flow path having the inlet relatively large and making the cross-sectional area of the flow path having the lower gas outlet of the furnace relatively small, the suction gas flow rate depending on the vertical position of the wafer is made uniform. To do. In FIG. 2, the desired effect is achieved by adjusting the width of the flow path.
Hereinafter, the present invention will be described in more detail with reference to examples.
[0025]
【Example】
  Figure 2The device of the present inventionOne embodiment is shown, and this apparatus basically comprises a heating furnace 1 and a wafer lifting mechanism 30. A normal reaction tube made of SiC, quartz or the like (hereinafter referred to as “quartz reaction tube”) 2 is a tubular body having an upper end closed and a lower end opened, and is provided so as to surround the upper outer periphery thereof. The heater 3 to be produced is fixed to the furnace body 4 made of a heat insulating material. The quartz reaction tube 2 is hermetically and detachably fixed to the furnace bottom structure 37 at the lower end bent in an L shape, and is supported by the support base 6. In the state shown in the drawing, the wafer 5 is raised to the upper limit position by the wafer lifting mechanism 30. Multistage and between each other5mmThey were stacked at the above intervals. The wafer 5 having a diameter of 8 to 12 inches is heated to a predetermined temperature by the heater 3. Although 5 'is a dummy wafer, its support is not shown.
[0026]
The wafer elevating mechanism 30 has a shelf-like quartz boat 18 in which the wafers 5 are vertically arranged on a rotary shaft body 32 having a separator 31 having a heat insulating function for preventing the members 33 and 34 below to be insulated. For example, as disclosed in Japanese Patent Application Laid-Open No. 9-17739 (FIGS. 8 and 9) of the present applicant. A magnet or coil 33 is attached to the lower end of the rotary shaft 32, and another magnet or coil 34 that exerts a rotational force on the magnet or coil 33 is provided so as to move up and down, thereby raising and lowering the wafer lifting mechanism 30. At the same time, the rotating shaft 32 is rotated. In order to perform such ascending / descending, a rod 36 screwed with a table 35 that supports a magnet 34 and the like is rotated by a driving device 40a.
[0027]
A tube body 42 that guides the ascending / descending of the rotary shaft 32 and a furnace bottom structure 37 integrally connected to the bottom of the heating furnace on the upper side thereof are airtightly fixed at the position shown in the figure during processing of the wafer 5. When the rod 38 rotatably connected to the support base 6 is rotated by the driving device 40b in the front and rear, the connecting portion 39 screwed to the rod 38 and fixed to the furnace bottom structure 37 is raised and lowered along the rod 38. Is done. Along with this, the furnace bottom is opened or closed. A small amount of N enters the furnace through the inside of the tube body 42 that guides the raising and lowering of the rotary shaft body 32.₂ A purge gas such as a gas can be sent from the inlet 42a.
[0028]
The rod 36, the driving device 40a, and the connecting portion 41 are mechanisms for moving the table 35 up and down. When the rod 36 is rotated by the driving device 40a, the table 35 screwed with the rod 36 slides on the tube 42 and moves up and down. Then, the position of the rotary shaft 32 in the vertical direction is adjusted.
[0029]
In FIG. 2, reference numeral 10 denotes first gas guiding means for distributing and ejecting the reaction gas supplied from the mother pipe 12 between the individual wafers 5, and 20 sucks the reaction gas from between the individual wafers 5. Second gas guiding means. Reference numeral 22 denotes an exhaust pipe that communicates with the second gas guiding means 20, and a reaction gas is sucked by a pump and a pressure measuring device 41 is attached thereto. Since the reaction gas ejection holes and the reaction gas suction holes, which will be described later, are positioned so as to face the gap between the wafers 5 arranged one above the other, the reaction gas is directly ejected into the wafer gap and directly exhausted from the gap. A laminar flow state can be realized in the inner space. That is, when a part of the reaction gas flow that flows upward or downward in the furnace space is divided into the wafer gap as in the conventional case, the gas flow stays between the wafers and is difficult to control in the individual gaps. However, according to the present invention, such stagnation is avoided and control in individual gaps is also possible.
[0030]
The second gas guiding means 20 includes the same number of wide suction holes 21 (second hole portions) as the wafer gap as shown in FIG. In order to suck the reaction gas layer spread over the entire wafer surface in the gap between the wafers without being mixed between the upper and lower layers, the suction hole 21 should be as wide as possible, and the preferred thickness is 0.5 to 1.5 mm. It is.
[0031]
FIG. 4 is a cross-sectional view taken along the line AA. The first gas guiding means 10 is composed of three pipe bodies 10a, 10b, 10b branched from a common mother pipe 12. That is, in the case of CVD using three kinds of gases, if the reaction gas is guided by one tube body, the reaction gas reacts before jetting, so the first gas guiding means is formed from the three tube bodies. The total area of the ejection holes of the first gas guiding means 10 is preferably equal to or smaller than the cross-sectional area of the mother pipe.
The second gas guiding means 20 is located in the direction opposite to the first tubular body 10 around the central axis of the wafer. Therefore, for example, a straight line connecting the tube body 10a, the wafer center, and the second gas guiding means 20 can be drawn. The second gas guiding means 20 is a box which connects an outer arcuate portion 20a, an inner flat portion 20b having a suction hole 21 formed vertically and a side surface portion 20c (see FIG. 2). By guiding, mixing with the gas in the furnace and diffusion into the furnace are avoided. As shown in FIG. 2, two partition plates 20d are provided in the second gas guide means 20 along the gas flow path so that the suction flow rates from the upper and lower wafers are substantially equal. Accordingly, the reaction gas from the upper wafer has a long flow distance and a large flow resistance. Therefore, the flow resistance is reduced by increasing the cross-sectional area.
[0032]
As shown in one embodiment of FIGS. 2 and 4, the tubes 10a, 10b, and 10c constituting the first gas guiding means pass through the annular partition plate 26. This annular partition plate 26 is shown in FIG. As shown, the outer periphery is fixed to the inner wall of the quartz reaction tube 2, and the inner periphery is annularly formed on the outer periphery of the wafer support jig 32 through a gap 27 that is as narrow as possible within the range in which the quartz boat 18 can rotate. It faces the extending outer ring portion 18a. Further, as shown in FIG. 2, the annular partition plates 26 are provided in the same number as the wafer.
In FIG. 5, which is an enlarged view of the portion C in FIG. 2, 17 is a gas nozzle including a first hole formed in the wall portion of the first gas guiding means 10. The reactive gas ejected from the gas nozzle 17 flows toward the second gas guiding means (not shown) as shown by the arrow. This gas flow comes into contact with the lower wafer 5 to form a poly Si film or the like of the semiconductor device, and further contacts with the upper wafer 5 to form a thin poly Si film or the like on the lower surface of the wafer where the semiconductor device is not formed. .
[0033]
In order to make the film formed on the lower surface thicker, a part of the reaction gas that should flow on the upper side of the wafer is made to flow downward by raising the pins 19. In this way, the difference in film thickness between the upper and lower surfaces is reduced and the warpage of the wafer is further reduced.
The annular partition plate 26 and the outer ring portion 18a are arranged so that the reaction gas layer ejected from one gas nozzle 17 is not substantially mixed before the reaction between the reaction gas layers from the upper and lower gas nozzles 17 and the wafer 5 due to diffusion. 3 and 4 as gas guiding means. Since the upper and lower reaction gas layers are not mixed as described above, the flow rate and distribution of the reaction gas supplied to each wafer 5 are hardly affected by those of other wafers.
As shown in FIG. 6, which is an enlarged view of part D in FIG. 2, the reaction gas ejected from the first gas guiding means (not shown) is directed toward the intake hole 21 of the second gas guiding means 20. It is jetting.
Since the annular partition plate 26 separates the upper and lower spaces just before the intake hole 21 and the gap 27 is set narrower, the reaction gas layer contributing to the reaction on the surface of the wafer 5 is substantially different from the upper and lower gas layers. The air flows into the intake hole 21 without being mixed.
[0034]
FIG. 7 schematically shows a reactive gas flow ejected from the first gas guiding means. That is, as the reaction gas flow is slightly bent in the rotation direction of the wafer (not shown), the fan-shaped pattern is also deformed, and the gas flow is slightly diffused in the width direction, but the gas concentration portion is illustrated. Yes. As shown in the figure, the reactive gas flows on the wafer surface by jetting and suctioning without being involved.
From the tubes 10a, 10b, and 10c of the first gas guiding means, it is possible to flow a different kind of reaction gas such as silane, phosphine, diborane, or the same kind of reaction gas. The ejected gas flow is preferably ejected from the tubes 10a, 10b, and 10c so that the angle θ is 30 to 40 °. Since the concentration of the reactive gas in contact with the wafer 5 is locally reduced, the film growth on the wafer 5 surface is made uniform by rotating the wafer 5.
[0035]
Returning to FIG. 2 again, 15 is a purge gas introduction pipe, and N₂ By flowing a small amount of non-reactive gas such as Ar and inert gas such as Ar, generation of particles in the lower part of the furnace due to a small amount of reactive gas flowing into the lower part of the furnace is prevented. If this purge gas blows up more than the gap 27 (FIGS. 5 and 6), the flow of the reaction gas described above is disturbed, so that the purge amount is extremely small and / or a pipe provided at the position 15 ′. It is necessary to exhaust more.
[0036]
FIG. 8 shows a structure of a support jig for the wafer 5 according to one embodiment.
The shelf or quartz boat 18 supporting the wafer 5 distributes an appropriate number of pins 19 to the inner ring portion 7a and the outer ring portion 7b to support the wafer 5 from the lower side in a point contact manner. These connecting portions 7c are radially provided at equal angles between the outer ring portion 18a and the inner ring portion 10b. Two or more inner ring portions 7a may be provided when the wafer diameter is large.
Further, the connecting portion 7d with the quartz boat 18 is radially projected on the outermost part, and this (7d) is fixed to the quartz boat 18. These portions 7a, b, c, and d are formed by punching out unnecessary portions or separating them by etching or the like on a sheet of silicon wafer or the like. Reference numeral 24 denotes a column for arranging and fixing the quartz boats 18 vertically. According to the method for supporting the wafer 5 shown in FIG. 8, since the wafer is supported on the outer peripheral side (7b) and the central portion (7a), warpage is extremely reduced.
[0037]
FIG. 9 is a plan view of a jig according to an embodiment for taking a wafer in and out of the quartz boat 18. That is, since the conventional boat has a horseshoe shape, the wafer can be loaded from the open portion. However, in the annular support structure shown in FIG. 8, the interference between the loading jig, the quartz boat 18 and the wafer supporting jig 7. Happens. Therefore, the wafer loading / unloading jig 50 according to the present invention basically has a fork-like upper part 51 that moves forward and backward horizontally above the quartz boat 18 and the wafer support jig 7 and horizontally below these (18, 7). The wafer is taken out by lifting the wafer in the lower part 52, and lifting the wafer lifted by the fork-like upper part 51 from the lower side with the fork-like tip 51a. In the loading of the wafer, the wafer is advanced to a predetermined position by the fork-shaped upper part 51, the lower part 52 advanced to this position is raised, the wafer is supported from below by supporting the wafer from below. Place on the jig 7. The fork-shaped tip 51a is formed with an arcuate recess 51c having a diameter slightly smaller than the diameter of the wafer to stabilize the position of the wafer.
FIG. 10 shows a state where the wafer 5 is lifted from the jig 7 during the series of operations described above. In the figure, reference numeral 52a denotes a protrusion for lifting the wafer 5. The height is determined to be smaller than the distance between the upper and lower support jigs 7 and larger than the height of the quartz boat 18, and the diameter is the inner diameter. It is smaller than the ring portion 7a and is determined so that the wafer does not become unstable.
[0038]
In FIG. 9, the wafer is lifted by the lower part that can be advanced and retracted. However, as shown in FIG. 11, by providing three rod receivers 52 that go up and down through the excised part of the wafer support jig, At the time of entry, the wafers 5 are loaded in order from the upper wafer, and at the time of removal, the wafers 5 are removed in order from the lower wafer 5. Reference numeral 51 denotes a jig having the same function as 51 in FIG.
[0039]
Subsequently, a more preferred embodiment of the apparatus according to the present invention will be described.
Normally, the flow rate of the gas flowing from the ejection hole of the first gas guiding means composed of a single pipe decreases toward the tip. In order to avoid this, it is only necessary to increase the diameter of the ejection hole or the inner diameter of the pipe toward the tip, but it is difficult to accurately control the flow rate. Therefore, it is preferable to equalize the gas flow rate from all the ejection holes by including a portion for flowing gas upward and a portion for flowing downward in the same gas guiding means, and arranging these portions in parallel. The gas supply source may be common to these parts, or may be individually provided for each part. Specifically, as shown in FIG. 12 (illustration of the ejection holes is omitted), the first tubular body 10 bifurcates the mother pipe 12 and one branching portion 10a extends upward, The other branch portion 10b is once extended upward and then turned 180 ° and extended downward (10b).₍₁₎ ), The upward extension 10a and the downward extension (10b).₍₁₎ The number of reactive gas outlets 11 can be formed as many as the number of wafer intervals. If the reaction gas is allowed to flow out only from the upward extension 10a, the gas flow rate distribution increases in the lower wafer, but in addition to this, the downward extension 10b.₍₁₎ By providing the above, it is possible to average such a gas flow rate distribution. Furthermore, more preferable results can be obtained when the total area of the ejection holes is substantially equal to or less than the cross-sectional area of the mother pipe.
[0040]
Various known techniques can be additionally applied to the apparatus of the present invention described above. This includes the following:
      (I)Applicant'sA known plasma cleaning is performed in Japanese Patent No. 2025683. In this case, it is preferable that all members exposed to plasma inside the furnace body are made of quartz.
      (B)Applicant'sHot as known in Utility Model Registration No. 3037794WallA cold wall furnace in the furnace (ie the heating furnace according to the invention)Match.
[0041]
In the present invention,When CVD growth of polysilicon is performed, it can be grown at a growth rate of 300 to 2000 mm / min and a film thickness distribution within 2 to 5%. In addition, when CVD growth of HTO is performed, it is possible to grow at a growth rate of 30 to 150 cm / min and a film thickness distribution of 1 to 4% with an 8-inch wafer.
[0042]
【The invention's effect】
As described above, the present invention performs high-speed film formation on the wafer in the steps after CVD or direct reaction, and is comparable to the conventional method in terms of film thickness uniformity.
[Brief description of the drawings]
FIG. 1 is a partial perspective view of a conventional hot wall heating furnace.
FIG. 2One aspect of the deviceIt is sectional drawing of the heating furnace which concerns on.
3 is a cross-sectional view taken along line BB in FIG.
4 is a cross-sectional view taken along line AA in FIG.
FIG. 5 is an enlarged view of a portion C in FIG.
6 is an enlarged view of a D part in FIG. 2. FIG.
FIG. 7 is a plan view schematically showing a reaction gas flow.
FIG. 8 is a plan view of a boat and a wafer support jig.
FIG. 9 is a plan view of a wafer loading / unloading jig.
FIG. 10 is an explanatory diagram of wafer loading / unloading.
11 is a plan view (a) and a side view (b) of a wafer loading / unloading jig according to another embodiment different from FIG. 8. FIG.
FIG. 12 is a view showing an embodiment of the first gas guiding means.
[Explanation of symbols]
        1 Heating furnace
        2 Quartz reaction tube
        3 Heater
        4 Furnace
        5 wafers
        7 Wafer support jig
        10 First tube
        12 Mother pipe
        15 Purge gas introduction nozzle
        17 Gas nozzle (first hole)
        18 boats
        19 pins
        20 Second gas guiding means
        21 Air intake holes
        22 Exhaust pipe
        24 props
        26 Annular divider
        27 Gap
        30 Wafer elevator
        31 Separator
        32 Rotating shaft
        33 Magnet or coil
        34 Magnet or coil
        35 units
        36 rods
        37 Furnace bottom structure
        38 rods
        39 Connection
        40 Driving means
        41 Pressure gauge
        42 tube
        50 Wafer access jig
        51 Fork-shaped upper part of wafer loading / unloading jig
        52 Bottom of wafer access jig

Claims (4)

Forming a film by chemical vapor deposition or direct reaction using a reaction gas on a semiconductor silicon wafer located in a soaking space formed in the reaction tube and in a soaking space formed in the reaction tube. A wafer supporting jig for holding two or more semiconductor silicon wafers each having a distance of 5 to 100 mm, and a wafer supporting jig orthogonal to the wafer surface. A driving means for rotating the semiconductor silicon wafer about the axis; a first gas guiding means for cutting off the reaction gas from the furnace gas and guiding the inside of the heating furnace to a position near the edge of the semiconductor silicon wafer; comprises a means for injecting into the gap of the semiconductor silicon wafer the entire amount of the reaction gas from the first gas guiding means in the edge vicinity to the wafer support jig, the carrier part The remaining plate is cut out and / or includes an outer ring portion, an inner ring portion and a connecting portion for connecting these, and from each hole portion of the first gas guiding means, the hole 3. A semiconductor device comprising: a third gas guiding means for restricting a reaction gas flow ejected toward a gap between the semiconductor silicon wafers facing the portion to flow into the upper and lower wafer gaps; Manufacturing equipment. The reaction gas flowing out from between the semiconductor silicon wafers is sucked through the second hole formed in the wall surface facing the gap between the semiconductor silicon wafers, and is shut off from the furnace gas and guided to the outside of the heating furnace. 2. The apparatus for manufacturing a semiconductor device according to claim 1, further comprising exhaust means connected to the gas guide means and the second gas guide means. Limiting the reaction gas flow from the upper and lower wafer gaps to mix with the reaction gas flow discharged from the gap between the semiconductor silicon wafers facing each hole toward the second hole of the second gas guiding means 3. The semiconductor device manufacturing apparatus according to claim 2, further comprising fourth gas guiding means. The inside of the second gas guiding means is divided into at least two parallel flow paths in the semiconductor silicon wafer arrangement region, and the cross-sectional area of the flow path communicating with the semiconductor silicon wafer located above the heating furnace is relatively small. 3. The apparatus for manufacturing a semiconductor device according to claim 2, wherein:

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