JP4581868B2 - Epitaxial growth apparatus and manufacturing method thereof - Google Patents

Description

  The present invention relates to a single-phase epitaxial growth apparatus, a manufacturing method thereof, and an epitaxial wafer, and more particularly to a technique suitable for use in homogenizing an epitaxial film.

In the field of semiconductor manufacturing, an epitaxial wafer in which an epitaxial film is grown on a silicon wafer substrate is conventionally known. An epitaxial wafer can form an epitaxial film having an arbitrary thickness and resistance on a substrate, and can solve a grow-in defect problem that hinders device fabrication.
In addition, the demand for miniaturization of semiconductor devices is increasing year by year, and the quality of epitaxial wafers used in connection therewith is also demanded. In particular, the uniformity of the epitaxial film thickness is an important requirement and greatly affects the lithographic process. In addition, when manufacturing a large number of devices from a single wafer, it is important to maintain the quality over a wide range on the wafer. In recent years, it has been included up to the vicinity of the wafer outer periphery (about 3 to 5 mm from the side of the wafer). Management has become necessary.
Vapor phase epitaxy is often used for epi-growth of silicon wafers. Silane gases (SiH ₄ , SiHCl ₃ , SiH ₂ Cl ₂ , SiCl ₄ ) are used as source gases, and H ₂ is used as a carrier gas. Many.

As described above, the following techniques are known as techniques for improving the uniformity of the epitaxial film thickness.
Japanese Patent Laid-Open No. 6-232060 JP 2002-43230 A

In the technique disclosed in Patent Document 1, two systems of gas supply are provided so that the gas supply is changed between the central portion and the peripheral portion of the wafer.
As described above, conventionally, as a method of adjusting the gas flow in the furnace, the main gas has two inlets, each of which is set to flow in the wafer central portion and the wafer outer peripheral portion, and the gas flow rate is adjusted independently. Therefore, a technique for controlling the gas flow in the furnace and making the epitaxial film thickness distribution in the wafer surface uniform is mainly taken.
In the technique disclosed in Patent Document 2, raw material gas and the like are supplied by a plurality of nozzles.

It is known that epitaxial growth is usually performed under a supply rate-controlled condition by heating a wafer to a high temperature, so that the epitaxial film thickness is easily affected by the flow velocity of gas flowing over the wafer.
However, in the conventional epitaxial manufacturing apparatus, the gas flow velocity flowing in the upper space of the wafer is different in the flow horizontal direction, so that the non-uniformity of the film thickness causes the flatness to deteriorate. The conventional main gas inflow mechanism is mainly divided into two systems in order to control the film thickness in the vicinity of the center and outer periphery of the wafer as in Patent Document 1, but the gas adjustment is Since there are only two systems, the central part of the wafer and the outer peripheral part, it is insufficient to adjust the complicated film thickness distribution, and it is difficult to make the film thickness uniform throughout the surface.

In addition, in an actual epitaxial growth apparatus, gas in-plane direction distribution and temperature distribution are generated, and these cause the film thickness uniformity, and in particular, single wafer type epitaxial wafer manufacturing. In the equipment, there are machine differences for each actual machine or each model, and it is necessary to change the gas flow rate, gas supply amount, etc. for each actual machine, which requires a large amount of work for gas flow rate control etc. There was a request to improve.
Furthermore, as in Patent Document 1 or Patent Document 2, when gas is directly supplied into the chamber by a plurality of nozzles, the flatness deteriorates in a strip shape so that the trace of gas flow is attached depending on the nozzle shape, and the film In some cases, the uniformity of the thickness is lowered, and the control is difficult.
In addition, as in Patent Document 1, when controlling the in-gas on the wafer center side and the out-gas on the wafer outer side, a partition plate (rectifier plate or the like) is provided so that these in / out gases do not mix on the way. when provided, by putting the partition plate, the gas flow at the partition plate near end up with different, there may result adverse effects on the wafer film thickness distribution.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an epitaxial growth apparatus that can improve the film thickness distribution uniformity of an epitaxial film formed on a wafer surface.

As a result of pursuing the cause of disturbance of the epitaxial film thickness distribution in the conventional epitaxial growth apparatus described above, the inventors found that the gas flow velocity flowing in the space above the wafer is different in the vertical direction in the wafer plane. I understood.
In addition, if a plurality of nozzles are provided to make the gas flow rate uniform, or if a configuration such as a rectifying plate is used, the turbulence of the generated gas flow can reach the wafer surface, which can disturb the thickness distribution. There is sex. Therefore, in the single wafer epitaxial growth apparatus, it is important to control the gas flow rate in accordance with the actual epitaxial film thickness.

From these findings, the epitaxial growth apparatus of the present invention, a chamber susceptor for holding the wafer along with the gas flow path is provided inside is provided in the gas passage, one end of the chamber An epitaxial growth apparatus comprising at least a gas supply port that is provided on a side and supplies gas into the chamber, and a gas discharge port that is provided on the other end side of the chamber and discharges gas from the chamber;
The gas flow rate is controlled by compensating for the film thickness distribution of the epitaxial film formed on the wafer as a gas supply port with a uniform height in the height direction, which is the normal direction of the wafer, in the cross-sectional shape of the gas supply port. When setting corresponding to the film thickness distribution of the epitaxial film,
The gas supply port height dimension is set in accordance with a vertically inverted shape with respect to the gas supply port width direction position in the film thickness distribution of the epitaxial film formed on the wafer with the gas supply port having a uniform height. .
The epitaxial growth apparatus of the present invention includes a chamber in which a gas flow path is provided and a susceptor for holding a wafer is provided in the gas flow path, and one end side of the chamber is provided in the chamber. An epitaxial growth apparatus comprising at least a gas supply port for supplying a gas and a gas discharge port provided on the other end side of the chamber for discharging gas from the chamber;
The gas flow rate is controlled by compensating for the film thickness distribution of the epitaxial film formed on the wafer as a gas supply port with a uniform height in the height direction, which is the normal direction of the wafer, in the cross-sectional shape of the gas supply port. Thus, the above-mentioned problem has been solved by setting the thickness corresponding to the film thickness distribution of the epitaxial film.
This onset Ming, the sectional shape of the gas supply port is preferably formed by the height dimension is set for each of a plurality of width regions divided in the width direction.
The setting width h ₀ of the height of the front SL gas supply port, is the height uniform range of about -30% to +30% of the height dimension in the gas supply port in compensating for the film thickness distribution Sometimes.
In the production process of the present onset Ming epitaxial growth apparatus, a method for producing an epitaxial growth apparatus according to any one of the above,
Forming an epitaxial film on the wafer as a gas supply port having a uniform height, and measuring a film thickness distribution of the epitaxial film;
In correspondence with the film thickness distribution of the epitaxial film, the step of setting the height dimension of the gas supply port corresponding to the gas flow rate for compensating the film thickness distribution;
The above-mentioned problem was solved by having.
This onset Ming, in the step of setting the height of the gas supply port,
Obtain the extreme value of the film thickness in the graph of the film thickness distribution of the epitaxial film,
Among these extreme values, each intermediate point of the extreme values and the end points of the film thickness distribution are set as height setting points,
Among the extreme values, the difference between the maximum value and the minimum value is set to 1, and the difference from the minimum value to each height set point is set to h, and the gas supply port height dimension uniform in the width direction is set. H ₀ , when the set width of the gas supply port height dimension for the gas supply port height dimension H ₀ uniform in the width direction is h ₀ ,
The height dimension of the portion corresponding to each of the height setting points is expressed by the formula (1)

H = H ₀ + (1-2h) × (H ₀ × h ₀ ) (1)

Is preferably set by:
Furthermore, the present invention is, as the cross-sectional shape of the gas supply port, it is possible to set the height for each of the plurality of wide regions divided in the width direction.
In the method of manufacturing an epitaxial growth apparatus of the present invention, in the step of setting the cross-sectional shape of the gas supply port,
The gas supply port height dimension is set so that the flow velocity of the gas flowing on the wafer to be epitaxially grown is increased when the epitaxial film is thin, and decreased when the epitaxial film is thick, at the position in the width direction of the gas supply port. In addition, the film thickness distribution can be compensated.
This onset Ming epitaxial wafer can be employed means which is produced by the epitaxial growth apparatus according to any one, or an epitaxial growth apparatus manufactured by the manufacturing method according to any one of the above.

In the epitaxial growth apparatus of the present onset Ming, a chamber susceptor for holding the wafer along with the gas flow path is provided inside is provided in the gas passage, provided at one end of the chamber the chamber A single wafer type epitaxial growth apparatus comprising at least a gas supply port for supplying gas therein and a gas exhaust port provided on the other end side of the chamber for discharging gas from the chamber;
Of the cross-sectional shape of the gas supply port, the width direction dimension that is the wafer in-plane direction is a dimension that can supply the gas to the entire wafer surface,
The gas flow rate is controlled by compensating for the film thickness distribution of the epitaxial film formed on the wafer as a gas supply port with a uniform height in the height direction, which is the normal direction of the wafer, in the cross-sectional shape of the gas supply port. Thus, by being set corresponding to the film thickness distribution of the epitaxial film, it becomes possible to increase or decrease the flow rate of the gas flowing on the wafer to be epitaxially grown in accordance with the film thickness of the epitaxial film. Since the supply gas can be supplied into the chamber so that the gas flow rate is increased where the film thickness is thin and the gas flow rate is decreased where the film thickness is thick, the film thickness of the epitaxially grown film can be made more uniform. Become.

In the case of an epitaxial growth apparatus in which the chamber has a substantially circular shape in plan view, while the reaction gas is introduced and the gas flows into the space above the wafer, the reaction gas passage has a vertical collision wall and a horizontal collision wall. The height of the collision wall surface will be different in the circumferential direction.
Further, the gas supply port cross-sectional shape can be maintained with a predetermined length dimension in the gas flow direction from the chamber inflow position to the chamber outer side direction. When the chamber is substantially circular in plan view, the gas supply port cross-sectional shape is maintained in the radial direction.
Actually, as will be described later, the gas supply port is composed of an upper surface of the middle ring portion and a groove (notch) formed at a corresponding position of the upper dome portion that forms a chamber in combination with the middle ring portion. The cross-sectional shape of the gas supply port is set by adjusting the formation state of the groove. In addition to this, a supply port as a separate member is provided, a gas supply port is provided by providing a through-hole in a member constituting the chamber, not only the upper dome portion and the middle ring portion, but also other components It is also possible to configure the gas supply port by combining them.

This onset Ming, the sectional shape of the gas supply port, by the height dimension be set for each of a plurality of width regions divided in the width direction, forming the gas supply port of quartz or the like configuration it becomes possible to perform the gas flow rate control while preventing workability decrease in member, it is possible to produce a homogeneous epitaxial wafer having a thickness at a low cost.

By becoming it is set to the width region number eg 11 of the onset light of the gas supply port, as described below, the width a gas supply port, the two systems for supplying gas to the wafer center side and the peripheral side When the film thickness is divided into three in the direction and the film thickness distribution as shown in FIG. 6 is compensated, the height dimension of each region can be easily set.
Also, setting the width h ₀ of the height of the gas supply port, is the height uniform range of about -30% to +30% of the height dimension in the gas supply port in compensating for the film thickness distribution Thus, it is possible to sufficiently compensate the film thickness distribution by controlling the gas flow rate.

In the production process of the present onset Ming epitaxial growth apparatus, and a step of depositing an epitaxial layer on the wafer, measuring the thickness distribution of the film thickness distribution of the epitaxial film as the height uniform gas supply port,
In correspondence with the film thickness distribution of the epitaxial film, the step of setting the height dimension of the gas supply port corresponding to the gas flow rate for compensating the film thickness distribution;
The non-uniformity in the thickness of the epitaxially grown film formed in the actual epitaxial growth apparatus can be caused by temperature, gas amount, turbulent flow, and many other causes. By controlling the gas flow rate by setting the gas supply port height based on this film formation data, it becomes possible to compensate for the increase or decrease in the epitaxial film thickness, whatever the cause, The film thickness uniformity can be dramatically improved. Moreover, it is possible to control the gas flow rate according to the actual epitaxial film thickness without providing a plurality of nozzles in order to make the gas flow rate uniform or adding a configuration such as a rectifying plate.

This onset Ming, in the step of setting the height of the gas supply port,
Obtain the extreme value of the film thickness in the graph of the film thickness distribution of the epitaxial film,
Among these extreme values, each intermediate point of the extreme values and the end points of the film thickness distribution are set as height setting points,
Among the extreme values, the difference between the maximum value and the minimum value is set to 1, and the difference from the minimum value to each height set point is set to h, and the gas supply port height dimension uniform in the width direction is set. H ₀ , when the set width of the gas supply port height dimension for the gas supply port height dimension H ₀ uniform in the width direction is h ₀ ,
The height dimension of the portion corresponding to each of the height setting points is expressed by the formula (1)

H = H ₀ + (1-2h) × (H ₀ × h ₀ ) (1)

Thus, the height of the gas supply port can be set more easily, and the gas flow rate can be controlled in accordance with the actual epitaxial film thickness.

  The cross-sectional shape of the gas supply port is based on a rectangular cross-sectional shape, and an epitaxial film is experimentally grown at the gas supply port of this basic shape. The film thickness distribution is plotted on the horizontal axis. Then, the height of the gas supply port can be made to match the shape of the graph of the film thickness distribution inverted upside down. At this time, it is preferable that the bottom side is a straight line and the upper side is a curve corresponding to the graph in terms of the ease of processing of the parts in manufacturing the epitaxial growth apparatus. This method is ideal for compensating the film thickness distribution.

  Actually, it is preferable to set the height dimension for each of the width regions divided into a plurality of width directions for ease of processing. This is because the temperature of the gas supply port close to the chamber becomes as high as or close to that in the chamber, so the parts that serve as the gas supply port are often made of quartz, as are the components that make up the chamber. This is because the shape is formed by grinding, but it is difficult to form a complicated curved surface corresponding to the film thickness distribution at the time of manufacturing the part by cutting in this way.

Specifically, the single-wafer epitaxial growth apparatus includes a ring-shaped middle ring positioned outside the susceptor between an upper dome portion made of quartz and a lower dome portion that is combined with the upper dome portion to form a chamber. The upper dome portion, the middle ring portion, and the lower dome portion constitute a general chamber.
In the case of a gas supply port having a uniform height, a gas supply port is formed by forming a groove to be a notch at the lower end of the upper dome portion and combining this groove with the upper plane of the middle ring portion. .

  Therefore, in order to set the height dimension as described above, the shape of the groove formed in the upper dome portion is set according to the height dimension setting described above, and the upper surface of the middle ring portion is left flat. Can do. Of course, the groove shape of the upper dome portion can be formed on the upper surface of the middle ring portion so as to have the above-described height dimension corresponding to the groove of the upper dome portion while the groove shape of the upper dome portion remains flat.

  For epitaxial growth equipment that flows into the furnace after the main gas collides with the vertical wall, the epitaxial film thickness of the wafer is controlled by changing the ceiling height of the inlet in several areas and controlling the gas flow rate. Uniformity can be improved.

Therefore, the present invention is, as the cross-sectional shape of the gas supply port, it is preferable to set the height for each of the plurality of wide regions divided in the width direction.

  In each width region, the height dimension set by Expression (1) can be set at the height set point corresponding to each region.

  When the gas supply port is divided into two systems corresponding to the center side and the peripheral side of the wafer, that is, when the gas supply port is divided into the outer part, the middle part, and the outer part in the width direction. The width region corresponding to the maximum value is set so as to correspond to the outermost side of the middle side portion, and the remaining width regions other than this are divided at equal widths. In general, in an epitaxial growth apparatus having a gas supply port having a uniform height, the film thickness distribution is often a “double mountain shape” as shown by black circles ● in FIG. The number of divisions of the width region is 11.

  Furthermore, when processing a wafer having a larger diameter, the number of divisions is set to 11 or more, and a number of height setting points are set on the graph of the film thickness distribution so as to correspond to the number of divisions. The height dimension can be set by the equation (1) at the height setting point.

More specifically, in the step of setting the height dimension of the gas supply port, first, a graph of the film thickness distribution of the epitaxial film is drawn as shown by black circles ● in FIG. In FIG. 6, the vertical axis represents the epitaxial film thickness (μm), and the horizontal axis represents the distance (mm) from the wafer center.
Next, as shown in FIG. 7A schematically showing the graph of FIG. 6, the extreme value of the film thickness in the graph of the film thickness distribution of the epitaxial film is obtained, and the broken line is horizontally placed so as to pass through each extreme value. Pull on.
Next, as shown in FIG. 7B, in the graph of the film thickness distribution of the epitaxial film, the extreme points of the extreme values and the end points of the film thickness distribution among these extreme values are set as height setting points, As shown in FIG. 7B, a solid line passing through each height set point is drawn horizontally.
Among the extreme values, the minimum extreme value, that is, the difference between the maximum value and the minimum value, that is, the difference between the maximum film thickness value and the minimum film thickness value, with the horizontal line corresponding to the minimum film thickness value as the reference line. The height dimension is 1, and the difference in height dimension from the minimum value to each height set point is h.
In the width direction of the epitaxial manufacturing apparatus used in the step of measuring the film thickness distribution of the epitaxial film thickness distribution, the number of divisions in the width direction of the gas supply port and the number of height reference points are set to the same number. uniform gas supply port of the height and H _0, when the uniform gas supply opening height gas supply port for the dimension H ₀ height of the setting range (the maximum change absolute value) was h ₀ in the width direction,
The height dimension of the portion corresponding to each of the height setting points is expressed by equation (1)
H = H ₀ + (1-2h) × (H ₀ × h ₀ ) (1)
Is set to H set by.

  When the gas flow rate is set so as to compensate for the film thickness by setting the height of the gas supply port as described above, the apparatus can be controlled by the same supply gas recipe in a plurality of epitaxial growth apparatuses. Therefore, the film thickness uniformity can be simultaneously controlled to the same level in a plurality of epitaxial growth apparatuses.

This onset Ming epitaxial wafers, the epitaxial growth apparatus as set forth in any one of the above, or by employing a means which is produced by epitaxial growth apparatus manufactured by the manufacturing method according to any one of the above, a uniform epitaxial epitaxial film A wafer can be easily obtained.

  According to the present invention, by setting the height of the gas supply port as described above, the gas flow rate is set so as to compensate the film thickness, the uniformity of the epitaxial film thickness of the wafer is improved, and the uniformity of the epitaxial film is achieved. It is possible to obtain an effect that a simple epitaxial wafer can be easily obtained.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
1 is a schematic side sectional view showing an epitaxial growth apparatus in the present embodiment, FIG. 2 is a schematic plan sectional view showing the epitaxial growth apparatus in the present embodiment as viewed in the direction of the arrow x in FIG. 1, and FIG. 3 is a gas supply in FIG. FIG. 4 is a front view of the gas supply port in FIG. 2 when the gas supply port has a uniform height, and FIG. 5 is a front view of the gas supply port set to a height. 2 is a front view of the gas supply port in FIG. 2 as viewed from the y direction. In the figure, reference numeral 1 denotes an epitaxial growth apparatus.

As shown in FIGS. 1 and 2, the epitaxial growth apparatus 1 according to the present embodiment includes a chamber including an upper dome portion 7, a lower dome portion 9, and a middle ring portion 8 provided therebetween, and the chamber Inside, a susceptor 11 holding a wafer 12 is provided so as to divide the chamber into a gas flow path (upper chamber interior) 2 and a lower chamber interior 3 by the wafer 12.
The susceptor 11 is rotatably supported by a susceptor support portion 16, and the susceptor support portion 16 can be rotated by a rotation drive mechanism (not shown) outside the chamber. A plurality of infrared lamps 15 and 15 are provided for heating the wafer 12 on the upper side of the upper dome portion 7 outside the chamber and on the lower side of the lower dome portion 9. A preheating ring 10 is provided outside the susceptor 11, and the upper surface of the preheating ring 10 is substantially flush with the surface of the wafer 12 on the susceptor 11. A structure in which the upper dome portion 7 is further disassembled into two upper and lower portions is also possible.

The middle ring portion 8 is a substantially cylindrical quartz member having a thickness, and its upper surface 81 is planar. The middle ring portion 8 includes notches having vertical curved surfaces 84 and 85 having bottom surfaces 82 and 83 that are substantially horizontal and concentric with the outer periphery on the outer peripheral side of the upper surface 81 at positions upstream and downstream of the gas flow path 2. 86 and 87 are provided. The notches 86 and 87 have a uniform dimension in the radial direction of the middle ring portion 8, and the circumferential direction of the middle ring portion 8 is somewhat the same as the radial dimension of the wafer 12 in the width direction of the gas flow path 2. The gas is supplied to the entire surface of the wafer 12 in the width direction of the gas flow path 2 of the gas flow supply port, as will be described later.
The upper surface of the inner ring portion 8 of the remaining heat ring 10 is separated from the upper inner portion 2 and the lower chamber portion 3 between the intermediate ring portion 8 and the susceptor 11 by the remaining heat ring 10. The convex part 88 which mounts the preheat ring 10 is provided so that 81 and the upper surface of the preheat ring 10 may become substantially the same plane.

The upper dome portion 7 is a cylindrical quartz member having the same diameter and the same width as that of the middle ring portion 8 closed by the lid portion integrated with the upper portion, and the lower end surface 71 is a flat surface in close contact with the upper surface 81 of the middle ring 8. It is made into a shape.
The upper dome portion 7 includes ceiling surfaces 72 and 73 and vertical curved surfaces 74 and 74 that face the bottom surfaces 82 and 83 and the vertical curved surfaces 84 and 85, respectively, at circumferential positions corresponding to the notches 86 and 87 of the middle ring portion 8. Notches 76 and 77 having 75 are provided on the inner circumference. At the outer peripheral positions of the notches 76 and 77, the lower end surface 71 a protrudes below the lower end surface 71.

By combining these notches 76 and 86, as shown in FIGS. 1 to 3, the gas supply port surrounded by the bottom surface 82, the vertical curved surface 84, the vertical curved surface 74, the ceiling surface 72, and a part of the top surface 81. Is formed. This gas supply port has different height positions at which the gas flows in and out at the outer peripheral position and the inner peripheral position of the middle ring portion 8, and the gas flowing in from the lower side enters the gas collision wall surface (vertical curved surface) 84. It collides and diffuses, and the flow rate is adjusted by a flow rate adjusting surface (ceiling surface) 72.
Similarly, by combining the notches 77 and 87, a gas discharge port surrounded by the bottom surface 83, the vertical curved surface 85, the vertical curved surface 75, the ceiling surface 73, and a part of the top surface 81 is formed. The height position where the gas flows in and out is different between the outer peripheral position and the inner peripheral position.

As shown in FIGS. 1 and 2, the gas supply port is connected to an introduction side rectification member 6 divided into two in the width direction of the gas flow path 2, and the introduction side rectification member 6 has a baffle with a hole. 5. An in-side introduction pipe 19 provided with an in-side flow rate regulator 17 and an out-side introduction pipe 20 provided with an out-side flow rate regulator 18 are connected via the gas introduction member 4. The in-side introduction pipe 19 and the out-side introduction pipe 20 are branched from a gas introduction pipe 21 connected to a gas supply means (not shown).
An exhaust side rectification member 13 is connected to the gas exhaust port, and a gas exhaust means (not shown) is connected to the exhaust side rectification member 13 via a gas exhaust member 14. In FIG. 2, the gas introduction member 4 and the gas exhaust member 14 are omitted.

Further, the bottom surface 82 of the lower side of the gas inlet position of the gas supply port, as shown in FIGS. 2 to 5, the gas supply port partition plate 8a which extends in the vertical direction and the gas flow velocity direction, 8b are provided . The upper ends of the gas supply port partition plates 8a and 8b are provided so as to be flush with the upper surface 81 of the middle ring portion 8, and the shape of the portion of the gas discharge port opened to the chamber is divided into a plurality of portions. It becomes one without.
Further, the introduction-side rectifying member 6 is also provided with rectifying member partition plates 6 a and 6 b continuously from these gas supply port partition plates 8 a and 8 b, and the center side (in side) of the wafer 12 and the outer periphery of the wafer 12. It separates so that the gas supplied to the side (out side) may be sent separately.

Among the cross-sectional shapes of the gas supply port, the cross-sectional shape at the position opened to the chamber has the height dimension set as follows.
Specifically, as shown in FIG. 4, the height direction dimension that is the normal direction (vertical direction) of the wafer 12 is the thickness distribution of the epitaxial film formed on the wafer as a gas supply port having a uniform height. The gas flow rate can be controlled so as to compensate and the film thickness of the epitaxial film to be formed becomes uniform, and is set corresponding to the film thickness distribution of the epitaxial film.
In the present embodiment, as shown in FIG. 5, the flow rate adjustment surface (ceiling surface) 72 of the gas supply port has a shape in which the gas flow rate can be controlled so as to compensate for the film thickness distribution of the epitaxial film.

Such a shape of the gas supply port, specifically, the setting of the flow rate adjustment surface (ceiling surface) 72 of the gas supply port is performed as follows.
First, in the epitaxial growth apparatus 1, as shown in FIG. 4, an epitaxial film is formed on a wafer with a gas supply port having a uniform height, and the film thickness distribution of the film thickness distribution of the epitaxial film is measured. And a step of setting a height dimension of the gas supply port corresponding to a gas flow rate for compensating the film thickness distribution corresponding to the film thickness distribution of the epitaxial film.

The cross-sectional shape of such a gas supply port is based on the rectangular cross-sectional shape shown in FIG. 4, and an epitaxial film is experimentally grown at the gas supply port of this basic shape. As shown in FIG. A graph of the film thickness distribution of the epitaxial film is drawn with the film thickness distribution as the vertical axis and the gas supply port width direction position, that is, the wafer radial direction as the horizontal axis.
In FIG. 6, the vertical axis represents the epitaxial film thickness (μm), and the horizontal axis represents the distance (mm) from the wafer center.
Ideally, the gas supply port height dimension is set in accordance with a vertically inverted shape of the graph of the film thickness distribution, that is, the bottom surface 82 side is a flat surface, and the flow rate adjusting surface (ceiling surface) 72 side is the above-described surface. Although it can be a curve corresponding to the graph, in order to process the quartz middle ring portion 8 and the upper dome portion 7, it is difficult to manufacture a part formed from a curved surface. Sets the shape of the flow control surface 72 as follows.

Next, in the step of setting the height dimension of the gas supply port, as shown in FIG. 7 (a) schematically showing the graph of FIG. 6, the poles of the film thickness in the graph of the film thickness distribution of the epitaxial film are shown. Find the value and draw a dashed line horizontally across each extreme.
Next, as shown in FIG. 7B, in the graph of the film thickness distribution of the epitaxial film, the extreme points of the extreme values and the end points of the film thickness distribution among these extreme values are set as height setting points, As shown in FIG. 7B, a solid line passing through each height set point is drawn horizontally.
As shown in FIG. 7C, among the extreme values, the difference between the maximum value and the minimum value, that is, the maximum film thickness value, with the horizontal line corresponding to the minimum film thickness value, that is, the minimum film thickness value as the reference line. The height dimension that is the difference between the minimum film thickness value and the minimum film thickness value is 1, and the height dimension difference from the minimum value to each height set point is h (0 ≦ h ≦ 1).

In the width direction of the epitaxial manufacturing apparatus used in the step of measuring the film thickness distribution of the epitaxial film thickness distribution, the number of divisions in the width direction of the gas supply port and the number of height reference points are set to the same number. uniform gas supply port of the height and H _0, when the uniform gas supply opening height gas supply port for the dimension H ₀ height of the setting range (the maximum change absolute value) was h ₀ in the width direction,
The height dimension of the portion corresponding to each of the height setting points is expressed by equation (1)
H = H ₀ + (1-2h) × (H ₀ × h ₀ ) (1)
As shown in FIG. 5, the gas flow rate is controlled by the shape of the flow rate adjusting surface (ceiling surface) 72 of the gas supply port to compensate for the film thickness distribution of the epitaxial film. .

Furthermore, in the case of a “double mountain shape” graph as shown in FIGS. 6 and 7, it is preferable to set the width region corresponding to the maximum value to be inside the gas supply port partition plates 8 a and 8 b. At this time, the width area is divided and set by equally dividing the remaining portion in the width direction.
According to the above procedure, the number of divisions of the width region is at least 11.
Further, in order to ensure the ease of setting, it is not necessary to determine the height setting value h of each region strictly corresponding to the graph, for example,
Five values H ₀ , H ₀ ± h ₁₁ , H ₀ ± h ₀₁ (h ₀₁ > h ₁₁ ),
It is possible to classify and set three types of values H ₀ and H ₀ ± h ₀₁ , that is, set a plurality of values selected from the graph.
In the case of this embodiment, in each width region, H _{0 is set} to 5 mm, plus h _{0 is set} to 0.2 (20%), and each width region is set to three kinds of heights of 4 mm, 5 mm, and 6 mm. And plus h ₀₁ = 1 mm .

In the epitaxial growth apparatus 1 of the present invention, during epitaxial growth, the wafer 12 is placed on the susceptor 11 and rotated by the susceptor support 16 at a constant rotational speed.
Next, a silane-based gas (SiH ₄ , SiCl ₂ H ₂ , SiHCl ₃ , SiCl ₄ ) and a carrier gas H _{2 that} are source gases are introduced from the gas introduction pipe 21, and are introduced into the in-side introduction pipe 19 and the out-side introduction pipe 20. After branching, the gas flow rate is adjusted by the in-side flow rate regulator 17 and the out-side flow rate regulator 18. Thereafter, the supply gas passes through the gas introduction member 4, the baffle 5 with holes, and the introduction side rectification member 6, diffuses on the gas collision wall surface 84 of the middle ring portion 8, and further enters the gas flow path 2 on the chamber upper ceiling surface 72. The direction is changed to flow on the wafer 12.
In this state, the wafer 12, the susceptor 11, and the ring 10 are heated by turning on the infrared lamp 15, and when the supply gas passes through the gas flow path (upper part in the chamber) 2 of the wafer 12, epitaxial growth occurs on the wafer 12. Occurs and an epitaxial film is formed.

  As shown in FIG. 3, normally, the in-side gas 23 and the out-side gases 22 and 24 that have passed through the holed baffle 5 diffuse on the gas collision wall surface 84 of the middle ring portion 8, and then the upper dome portion 7 and the middle ring. It flows into the chamber through the gap of the portion 8. The distance between the flow rate adjusting surface (ceiling surface) 72 and the upper surface 81 in the portion flowing into the chamber, that is, the height of the opening of the gas supply port is the same as the gas supply port in the circumferential direction shown in FIG. Since the height is set differently for each of the width regions divided in the circumferential direction shown in FIG. 5 so as to compensate for the film thickness in the case of having the gas, the supply gas is supplied to the wafer 12 in the chamber. A uniform epitaxial film can be grown.

  In the present embodiment, as shown in FIG. 6, the in-side gas that has flowed between the upper dome portion 7 and the middle ring portion 8 because the height from the upper surface 81 of the flow rate adjusting surface 72 is different in each region. 23, the flow rate of the out-side gases 22 and 24 can be adjusted to adjust the turbulence of the gas flow generated in each zone, and the film thickness uniformity of the epitaxial film formed on the wafer 12 can be improved.

(Experimental example)
An epitaxial film was actually grown by the epitaxial growth apparatus 1 of the present invention.
The case where the film is formed by the apparatus having the gas supply ports having the same height in the circumferential direction shown in FIG. 4 is set as Experimental Example 1, and the height is set differently for each width region divided in the circumferential direction shown in FIG. A case where a film is formed by a device that shakes the gas supply port is referred to as Experimental Example 2. In Experimental Example 2, the height setting of the gas supply port is changed according to the result of Experimental Example 1.
These results are shown in FIG.

The specifications of the experimental example are as follows.
Gas supply port dimensions H ₀ shown in FIGS. 4 and 5: 5 mm
Gas supply port dimensions shown in FIG.
h ₀ : 0.2 (20%)
Width of width region: 20-30mm
Height of each width area: (from right)
1: 5mm
2: 6 mm
3: 5 mm
4: 4 mm
5: 5mm
6: 6mm
7: 5mm
8: 4mm
9: 5mm
10: 6mm
11: 5mm
Gas flow rate Inn side: 30 slm
Out side: 20 slm
Wafer diameter: 200mm
Wafer temperature: 1100 ° C

  As a result, in the structure having the uniform-height gas supply port indicated by black circles ● in FIG. 6, large irregularities are generated in the wafer surface. However, as shown by black squares ■ in FIG. In the epitaxial growth apparatus 1, the uniformity of the film thickness was improved.

1 is a schematic side view showing an embodiment of an epitaxial growth apparatus according to the present invention. FIG. 2 is a schematic plan view of an embodiment of the epitaxial growth apparatus according to the present invention as viewed in the direction of arrow x in FIG. 1. It is the perspective view which looked at the gas supply port in FIG. 2 from the y direction. It is the front view which looked at the gas supply port in FIG. 2 from the y direction when a gas supply port is made into uniform height. FIG. 3 is a front view of the gas supply port in FIG. 2 when viewed from the y direction when the height of the gas supply port is set. It is a graph which shows the relationship with the epitaxial film thickness with respect to the distance from a wafer center. It is the figure (b) and (c) which show the height setting method of a gas supply port to the figure (a) and (a) which showed the graph of Drawing 6 typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Epitaxial growth apparatus 2 ... Gas flow path (upper part in chamber)
3 ... Lower part in chamber 4 ... Gas introduction member 5 ... Baffle 6 with holes ... Introducing side rectifying members 6a, 6b ... Rectifying member partition plate 7 ... Upper dome (chamber upper part)
72 ... Flow control surface (ceiling surface)
8 ... Middle ring part (quartz member)
8a, 8b ... gas supply port partition plate 84 ... gas collision wall surface (vertical curved surface)
DESCRIPTION OF SYMBOLS 9 ... Lower dome part 10 ... Preheating ring 11 ... Susceptor 12 ... Wafer 13 ... Exhaust side rectification member 14 ... Gas exhaust member 15 ... Infrared lamp 16 ... Susceptor support part 17 ... In side flow rate regulator 18 ... Out side flow rate regulator 19 ... In side introduction pipe 20 ... Out side introduction pipe 21 ... Gas introduction pipe

Claims (6)

A chamber in which a gas flow path is provided and a susceptor for holding a wafer is provided in the gas flow path, and a gas supply port that is provided on one end side of the chamber and supplies gas into the chamber And an epitaxial growth apparatus comprising at least a gas exhaust port that is provided on the other end side of the chamber and exhausts gas from the chamber,
The gas flow rate is controlled by compensating for the film thickness distribution of the epitaxial film formed on the wafer as a gas supply port with a uniform height in the height direction, which is the normal direction of the wafer, in the cross-sectional shape of the gas supply port. When setting corresponding to the film thickness distribution of the epitaxial film,
The gas supply port height dimension is set in accordance with a vertically inverted shape with respect to the gas supply port width direction position in the film thickness distribution of the epitaxial film formed on the wafer with the gas supply port having a uniform height. Epitaxial growth equipment. 2. The epitaxial growth apparatus according to claim 1, wherein the gas supply port has a cross-sectional shape in which the height dimension is set for each of a plurality of width regions divided in the width direction. A method of manufacturing an epitaxial growth apparatus according to claim 1 or 2 ,
Forming an epitaxial film on the wafer as a gas supply port having a uniform height, and measuring a film thickness distribution of the epitaxial film;
In correspondence with the film thickness distribution of the epitaxial film, the step of setting the height dimension of the gas supply port corresponding to the gas flow rate for compensating the film thickness distribution;
And a method of manufacturing an epitaxial growth apparatus. In the step of setting the height dimension of the gas supply port,
Obtain the extreme value of the film thickness in the graph of the film thickness distribution of the epitaxial film,
Among these extreme values, each intermediate point of the extreme values and the end points of the film thickness distribution are set as height setting points,
Among the extreme values, the difference between the maximum value and the minimum value is set to 1, and the difference from the minimum value to each height set point is set to h, and the gas supply port height dimension uniform in the width direction is set. H ₀ , when the set width of the gas supply port height dimension for the gas supply port height dimension H ₀ uniform in the width direction is h ₀ ,
The height dimension of the portion corresponding to each of the height setting points is expressed by the formula (1)

H = H ₀ + (1-2h) × (H ₀ × h ₀ ) (1)

The method of manufacturing an epitaxial growth apparatus according to claim 3, wherein: The method for manufacturing an epitaxial growth apparatus according to claim 4 , wherein the height dimension is set for each of a plurality of width regions divided in the width direction as a cross-sectional shape of the gas supply port. In the step of setting the cross-sectional shape of the gas supply port,
The gas supply port height dimension is set so that the flow velocity of the gas flowing on the wafer to be epitaxially grown is increased when the epitaxial film is thin, and decreased when the epitaxial film is thick, at the position in the gas supply width direction. 4. The method of manufacturing an epitaxial growth apparatus according to claim 3 , wherein the film thickness distribution is compensated.

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