JP4346563B2 - Chemical vapor deposition equipment - Google Patents

Description

  The present invention relates to a chemical vapor deposition apparatus for forming a thin film on the surface of a semiconductor wafer disposed in a reaction chamber by reaction of a reaction gas.

Conventionally, as a chemical vapor deposition apparatus for uniformly depositing a thin film on a large-area semiconductor wafer by chemical vapor deposition (CVD growth), a reaction plate is provided with a guide plate that vertically separates the reaction chamber, and is horizontally disposed on the guide plate. The susceptor is rotatably supported to flow the reaction gas along the upper surface of the guide plate from one side of the reaction chamber to the other, and the carrier gas flowing into the chamber below the guide plate While rotating the susceptor via a rotating blade provided on the lower surface thereof, the surface facing the upper surface of the semiconductor wafer supported on the upper surface of the susceptor is brought into contact with the reaction gas flowing in parallel with the surface, thereby the semiconductor A horizontal type chemical vapor deposition apparatus is known in which a thin film is formed on the surface of a wafer (see, for example, Patent Document 1). There is also known a vertical chemical vapor deposition apparatus having the same components as described above and having a susceptor rotating in a vertical plane (see, for example, Patent Document 2).
JP-A-11-116384 JP 11-116383 A

However, in the conventional chemical vapor deposition apparatus, since the reaction gas sent out from the gas supply mechanism flows parallel to the surface of the horizontal or vertical semiconductor wafer, the heated reaction gas is contained in itself. Since it tends to flow upward and quickly exits to the discharge port, it cannot contact the surface facing upward or perpendicular to the surface of the semiconductor wafer with sufficient urging pressure, resulting in a uniform required thickness for large-area semiconductor wafers. In the case of growing a thin film, the desired purpose cannot be achieved unless a huge amount of reaction gas (carrier gas such as source gas, hydrogen, or rare gas) is allowed to flow. There is a problem that the consumption of the reaction gas increases.
In addition, the gas that drives the rotating blades that rotate the susceptor on which the semiconductor wafer is mounted is supplied through a separate supply path, separately from the reaction gas that contacts the surface of the semiconductor wafer. There is a problem that the structure of the chamber becomes complicated, and the gas for driving the rotary blades may be mixed with the atmosphere for growing the reaction gas, which restricts the growth conditions.

  The present invention has been made in view of the above circumstances, and can reduce the amount of reaction gas used to uniformly form a thin film on the surface of a semiconductor wafer without being restricted by growth conditions. An object of the present invention is to provide a chemical vapor deposition apparatus capable of simplifying the structure of a reaction chamber.

The present invention is characterized by the following points in order to solve the above problems.
That is, the chemical vapor deposition apparatus according to claim 1 is a reaction chamber in which a reaction gas introduced from the outside to the inside can flow from the bottom to the top, the reaction chamber is rotatably provided, and the semiconductor wafer is placed on the bottom surface. A susceptor that can be mounted on a side of the susceptor, wherein the susceptor is rotated at the outer periphery of the region where the semiconductor wafer is mounted by rotating the susceptor in response to the flow of the reaction gas from below to above the susceptor. Means is provided.

  A chemical vapor deposition apparatus according to a second aspect is the chemical vapor deposition apparatus according to the first aspect, wherein the reactive gas is sprayed on a central portion of a surface facing the lower side of the semiconductor wafer mounted on the susceptor. It is characterized by having a nozzle to flow.

  The chemical vapor deposition apparatus according to claim 3 is the chemical vapor deposition apparatus according to claim 1 or 2, wherein the susceptor is provided in a bearing interposed between an upper surface of the chemical vapor deposition apparatus and a lower surface of the support portion of the reaction chamber. It is supported and provided so as to be rotatable around an axis.

  The chemical vapor deposition apparatus according to claim 4 is the chemical vapor deposition apparatus according to any one of claims 1 to 3, wherein the reaction chamber has a reaction at a position facing the rotation generating unit of the susceptor. An exhaust port is provided for discharging the reaction gas flowing through the room and passing through the rotation generating means.

The present invention has the following excellent effects.
That is, according to the chemical vapor deposition apparatus of the first aspect, the reaction gas is effectively urged and brought into contact with the surface facing the lower side of the semiconductor wafer by the upward flow, so that even a small amount of the reaction gas is efficient. A thin film having a predetermined thickness can be formed well, thereby reducing the amount of reaction gas used. In addition, since the reaction gas for forming the film on the semiconductor wafer is rotated by the rotation generating means, the susceptor does not need to flow the gas for rotating the susceptor to the rotation generating means through a route separate from the reaction gas. The structure of the reaction chamber can be simplified, and the gas for driving the rotation generating means is not likely to be mixed in the atmosphere for growing the reaction gas, and the growth conditions are not restricted.

  According to the chemical vapor deposition apparatus of the second aspect, since the reaction gas flows uniformly from the central portion of the semiconductor wafer toward the outer peripheral edge, the rotational force is generated evenly on the blades on the entire circumference of the susceptor. Thus, the susceptor can be smoothly rotated.

  According to the chemical vapor deposition apparatus of the third aspect, the susceptor that is levitated by the rising and flowing reaction gas is firmly supported by the support portion of the reaction chamber by the bearing and can rotate smoothly.

  Further, according to the chemical vapor deposition apparatus according to claim 4, without adding resistance to the reaction gas that has passed through the rotation generating means of the susceptor, the reaction gas can be smoothly discharged out of the reaction chamber, The susceptor can rotate stably and efficiently.

A chemical vapor deposition apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a chemical vapor deposition apparatus according to an embodiment of the present invention. The chemical vapor deposition apparatus 1 includes a reaction chamber 2 capable of flowing a reaction gas in an interior 2a, a susceptor 4 provided rotatably in the interior 2a of the reaction chamber 2, and capable of mounting a semiconductor wafer 3 on the lower surface side. A blade (rotation generating means) 5 for rotating the susceptor 4 with a flowing gas inside the reaction chamber 2, a heater 6 for heating the semiconductor wafer 3 mounted on the susceptor 4, and the surface of the semiconductor wafer 3 3a is provided with a nozzle 7 for spraying and flowing a reactive gas.
The reaction chamber 2 has a cylindrical (cylindrical) body portion 8 made of quartz, and a circularly fixed removably with an O-ring 9 interposed between an annular flange 8a on the upper portion of the body portion 8. A plate-like flange 10 is provided, and a lower annular flange 8b is fixed to the upper surface of the wall portion 11 of the load lock chamber in an airtight manner through an O-ring 9 so that the direction of the central axis S1 is vertical. It is installed towards. At the center of the flange 10 (position of the central axis S1), an exhaust port 10a penetrating vertically is provided.

  Below the reaction chamber 2, a flat partition wall (gate valve) 12 is joined to the lower surface of the wall portion 11 of the load lock chamber via an O-ring 9, and the opening portion 11 a of the wall portion 11 is opened. It is provided to be hermetically closed. In the interior 2a of the reaction chamber 2, a cylindrical (tubular) support leg 13 made of carbon is fixed at the lower end to the upper surface of the partition wall 12, and the axis is the central axis S1 of the reaction chamber 2. It is arranged to match. As shown in FIG. 2, a carbon-made disc-shaped cap 14 provided with a small-diameter support portion 14a protruding at the lower end is fitted at the upper end of the support leg 13 with a larger diameter than the intermediate support portion 14a. The wearing portion 14b is fitted into a large-diameter hole portion 13a provided at the upper end portion of the support leg 13, and is fixed via a flange 14c at the upper end.

  The susceptor 4 is made of carbon, and as shown in FIGS. 2 and 3, the susceptor 4 has an annular rim portion 4b protruding upward on the outer periphery of a disc-shaped wafer holder 4a. The blades 5 are integrally formed. On the lower surface of the wafer holder 4a, the semiconductor wafer 3 is spaced circumferentially on the outer peripheral side of the wafer holder 4a with the surface 3a facing downward and the center C aligned with the central axis S1 of the reaction chamber 2. A plurality of hook-shaped supports 15 arranged with a gap between them can be mounted. The blade 5 has a blade member 5a inclined with respect to the axis of the wafer holder 4a at a predetermined interval in the circumferential direction on the outer periphery of the rim portion 4b, that is, on the outer peripheral portion of the region where the semiconductor wafer 3 is mounted. It is formed in the same manner as the turbine blade by arranging a plurality of holes.

  The susceptor 4 is supported by a bearing 16 provided between the lower surface of the support portion 14a of the cap 14 and the upper surface of the wafer holder 4a so that the axis line coincides with the central axis S1 of the reaction chamber 2. It rotates around the central axis S1. The bearing 16 includes an annular groove 14d having a V-shaped cross section formed on the lower surface of the support portion 14a of the cap 14 along a circumference concentric with the central axis S1, and an upper surface 4d of the wafer holder 4a of the susceptor 4. Are fitted across the annular grooves 14d and 4e, and a circular groove 4e having a V-shaped cross section formed along a circumference that is concentric with the central axis S1 and has the same diameter as the circumference of the annular groove 14d. And a plurality of balls 16a arranged at intervals in the circumferential direction thereof. The balls 16a are made of carbon, and the surface thereof is coated with TaC so that they are not easily worn. The distance between the annular grooves 14d and 4e in the circumferential direction is kept constant by a retainer (not shown). Thus, it rolls in each annular groove 14d, 4e.

  The outer periphery of the blade member 5a is positioned in the large-diameter hole 13a of the support leg 13 with a gap g, and the lower end of the outer periphery of the blade member 5a is always due to the weight of the wafer holder 4a. When the wafer holder 4a is lifted and brought into contact with the cap 14 via the ball bearing 16, when the wafer holder 4a is lifted and brought into contact with the cap 14 through the ball bearing 16 The lower end of the outer periphery of the blade member 5a is separated from the step portion 13b, a gap is formed between the upper end of the outer periphery of the blade member 5a and the lower surface of the fitting portion 14b of the cap 14, and the outer peripheral portion of the support portion 14a. And a gap between the rim 4b of the susceptor 4 and the inner peripheral surface 4f. Further, at a position facing the blade 5 of the susceptor 4, a plurality of exhaust ports 14 e arranged at predetermined intervals along a circumference concentric with the central axis S <b> 1 of the cap 14 include the central axis S <b> 1. Is provided so as to penetrate up and down in parallel with each other. The exhaust port 14e may be a circular hole or an arcuate long hole along the circumferential direction.

The heater 6 is formed of a high frequency induction coil having a predetermined length (height) in the direction of the central axis S1, for example, and the center of the susceptor 4 in the longitudinal direction at the height position in the direction of the central axis S1. Is placed so as to surround the outer periphery of the reaction chamber 2, and the semiconductor wafer 3 mounted on the susceptor 4 is heated to, for example, about 1500 to 1800 ° C. by high frequency induction heating. It is like that.
The nozzle 7 is composed of a cylindrical nozzle tube 7a and a jacket tube 7c provided concentrically with an annular space 7b on the outside thereof, and the partition wall 12 is arranged with the axis S2 in the direction along the central axis S1. The upper end (front end) portion is penetrated and protrudes into the interior 2a of the support leg 13, and is fixed to the partition wall 12. A reaction gas supply source (not shown) reacts at the lower end of the nozzle tube 7a. Gas is supplied. Cooling water is supplied to the annular space 7b of the jacket pipe 7c through a cooling water pipe (not shown) so that the reaction gas flowing in the nozzle pipe 7a is cooled.

  Further, the upper end of the nozzle tube 7a is extended to the vicinity of the lower end (the lower end of the heating region of the heater 6) in the central axis S1 direction of the heater 6, and the front end opening 7d is mounted on the susceptor 4. The reaction gas supplied to the lower end of the nozzle tube 7a from the reaction gas supply source is sprayed from the tip opening 7d to the surface 3a of the semiconductor wafer 3 and flows. It has come to be. The position E of the tip opening 7d of the nozzle tube 7a (the position where the reactive gas is blown against the surface 3a of the semiconductor wafer 3) E is set to coincide with the center C of the semiconductor wafer 3.

In addition, a heat insulator 17 made of low-density carbon is disposed inside the reaction chamber 2 so as to surround the outer periphery of the support leg 13 and the outside of the cap 14. The heat insulator 17 is provided between the inner peripheral portion of the reaction chamber 2 and the outer peripheral portion of the support leg 13, and the lower end of the heat insulator 17 is outside the opening portion 11 a of the wall portion 11. A cylindrical (cylindrical) heat insulator body portion 17a fixed to the upper surface of the cap body 14, and a top plate 17b that is disposed above the cap 14 at an interval and closes the upper end of the heat insulator body portion 17a. The heat for heating the semiconductor wafer 3 is prevented from being dissipated to the outside. The top plate 17b is provided with an exhaust port 17c whose center coincides with the central axis S1.
The body 8 of the reaction chamber 2, the support leg 13, and the heat insulator body 17 a of the heat insulator 17 are not limited to a cylindrical shape, and may be formed in a rectangular tube shape or other tubular shapes.

Next, the operation of the chemical vapor deposition apparatus 1 configured as described above will be described.
After the semiconductor wafer 3 is mounted on the susceptor 4 in the load lock chamber, the support leg 13 is inserted into the reaction chamber 2 (in the heat insulator 17), and the partition wall 12 is joined to the wall portion 11 of the load lock chamber. The susceptor 4 is installed at a predetermined position inside the reaction chamber 2. Then, the heater 6 is operated, and a reactive gas (for example, carrier gas H ₂ and source gas SiH ₄ , C ₃ H ₈ ) is supplied from a reactive gas supply source to the nozzle tube 7 a of the nozzle 7. The reactive gas supplied to the nozzle tube 7a is ejected from the tip opening 7d of the nozzle tube 7a, and is sprayed vertically from below to above at the center C of the surface 3a of the semiconductor wafer 3. The reaction gas sprayed onto the surface 3a of the semiconductor wafer 3 causes the susceptor 4 to float by the pressure, and also flows through the semiconductor wafer 3 to the outer peripheral side of the susceptor 4 through the surface 3a. 5 receives and generates a rotational force to rotate the susceptor 4 around the center C. When the susceptor 4 is lifted by the pressure of the reaction gas, the lower end of the blade 5 is separated from the step portion 13b of the support leg 13, and is reliably supported by the support portion 14a of the cap 14 via the bearing 16. Smoothly rotates around S1. The reaction gas that has passed through the blades 5 passes through the exhaust port 14e on the outer periphery of the cap 14, passes through the exhaust port 17c of the heat insulator 17 and the exhaust port 10a of the flange 10 at the top of the reaction chamber 2, and thus the reaction chamber 2 It is discharged outside.

  By blowing the reaction gas from the nozzle tube 7a while the susceptor 4 is rotating, the reaction gas is effectively urged and brought into contact with the surface 3a of the semiconductor wafer 3 while flowing in the outer peripheral direction along the surface 3a. A thin film having a predetermined thickness is formed by an efficient CVD reaction. At this time, the reaction gas that flows from the outer peripheral portion of the semiconductor wafer 3 toward the blade 5 and generates a rotational force on the blade 5 is an unreacted gas among the reaction gases blown on the surface 3 a of the semiconductor wafer 3. And reaction product gas. Since the exhaust ports 17c and 10a for discharging the reaction gas (unreacted gas and carrier gas) to the outside of the reaction chamber 2 are provided at positions on the central axis S1 of the reaction chamber 2, the flow of the reaction gas Is preferable because it can be smoothly discharged without moving to one side of the reaction chamber 2. However, the exhaust ports 17c and 10a are not limited to the above positions, and may be provided at other positions.

During the CVD reaction, the susceptor 4 rotates the semiconductor wafer 3 with its center C aligned with the central axis S1 of the reaction chamber 2, so that the surface 3a of the semiconductor wafer 3 is moved by the heater 6. The whole is heated uniformly and temperature unevenness does not occur, and a thin film can be satisfactorily formed on the surface 3a of the semiconductor wafer 3.
The film thickness of the thin film formed on the surface 3a of the semiconductor wafer 3 is sprayed with the reaction gas because the tip opening 7d of the nozzle tube 7a is positioned at the center C of rotation of the semiconductor wafer 3. Although the central region is slightly thicker in a cross-sectional view and tends to gradually become thinner on both sides, it can be considered that the film thickness is formed uniformly over the entire surface 3a of the semiconductor wafer 3 for practical purposes. There is nothing.

As described above, the chemical vapor deposition apparatus 1 according to the embodiment includes the reaction chamber 2 that allows the reaction gas introduced from the outside to the inside 2a (inside the support leg 13) to flow upward from below, The reaction chamber 2 includes a susceptor 4 rotatably provided through a cap 14 fixed to a support leg 13 and capable of mounting the semiconductor wafer 3 on the lower surface side. The susceptor 4 includes a semiconductor wafer 3. 3 is provided with blades 5 as rotation generating means for rotating the susceptor 4 in response to the flow of the reaction gas in the outer peripheral portion of the region where the 3 is mounted.
Therefore, according to the chemical vapor deposition apparatus 1 according to the above-described embodiment, the reaction gas is effectively urged and brought into contact with the surface 3a facing downward of the semiconductor wafer 3 by the upward flow. A thin film having a predetermined thickness can be efficiently formed even with a reactive gas, whereby the amount of the reactive gas used can be reduced. In addition, the system for excluding the gas after reaction can be made compact.
Further, since the reaction gas after the thin film is formed on the semiconductor wafer 3 is rotated by the flow of the blade 5 to the susceptor 4, the gas for rotating the susceptor 4 is separated from the reaction gas with the blade 5. The reaction chamber 2 can be simplified in configuration, and the gas for driving the blades 5 is not likely to be mixed with the growth atmosphere of the reaction gas, and is not restricted by the growth conditions. .

Further, since the blades 5 are provided on the rim 4a, which is the outer peripheral portion of the susceptor 4, a wide area for mounting the semiconductor wafer 3 on the lower surface of the susceptor 4 can be secured, and a large area semiconductor The film formation of the wafer 3 can also be suitably handled.
Further, the surface 3a of the semiconductor wafer 3 is mounted on the lower surface of the susceptor 4 with the support 15 so that the reaction gas is satisfactorily applied to the surface 3a of the semiconductor wafer 3 by the upward flow generated by the temperature rise. From this point, the thin film can be efficiently formed on the surface 3a, and fine powder generated in the reaction chamber 2 is prevented from adhering to the surface 3a, thereby improving the quality of the thin film. Can do.
In addition, the susceptor 4 is disposed on the upper portion of the reaction chamber 2 (support leg 13) heated by the heater 6 and is adapted to rotate, but in order to rotate the susceptor 4, a sliding portion Therefore, there is no worry that the sliding portion of the rotating mechanism is exposed to high heat and worn out, and the maintenance of the apparatus is extremely easy.

In addition, according to the chemical vapor deposition apparatus 1 according to the above embodiment, the nozzle 7 for spraying and flowing the reactive gas to the center C of the surface 3a facing the lower side of the semiconductor wafer 3 mounted on the susceptor 4 is provided. Since the reaction gas flows evenly from the center of the semiconductor wafer 3 toward the outer peripheral edge, the rotational force is generated evenly on the blades 5 on the entire circumference of the susceptor 4, and the susceptor 4. Can be smoothly rotated.
Moreover, according to the chemical vapor deposition apparatus 1 according to the embodiment, the susceptor 4 has an upper surface thereof and a lower surface of a support portion 14 a provided on the cap 14 as a support portion of the susceptor 4 in the reaction chamber 2. Since it is supported by a bearing 16 interposed therebetween and is provided so as to be rotatable around an axis, the susceptor 4 that is levitated by the rising and flowing reaction gas is supported by the bearing 16 on the support portion 14 a of the cap 14. It is supported firmly and can rotate smoothly.

  In addition, according to the chemical vapor deposition apparatus 1 according to the embodiment, the cap 14 fixed to the support leg 13 is located at the position facing the blade 5 of the susceptor 4 and the inside 2 a of the support leg 13. The susceptor 4 is provided with an exhaust port 14e for exhausting the reaction gas flowing through the blade 5 and passing through the blade 5 from the support leg 13 which substantially functions as a reaction chamber for CVD reaction. Without adding resistance to the reaction gas passing through the blades 5, the reaction gas can be smoothly discharged out of the support legs 13, and the susceptor 4 can be stably and efficiently rotated.

  In the chemical vapor deposition apparatus 1 according to the above embodiment, the rotation generating means for obtaining the rotational force for rotating the susceptor 4 by the flow of the reaction gas is configured as the blade 5 having the same shape as the turbine blade. However, the rotation generating means is not limited to the blade 5, and as shown in FIG. 4, a rim portion 4b1 that is wide in the radial direction is formed on the outer periphery of the wafer holder 4a of the susceptor 4, and the rim portion 4b1 A plurality of exhaust ports 18 inclined with respect to the axis of the susceptor 4 may be provided at predetermined intervals in the circumferential direction of the rim portion 4b1. Also in this case, when the reaction gas flows and passes through the exhaust port 18, the inner wall surface of the exhaust port 18 functions in the same manner as the surface of the blade member 5 a of the blade 5, and the susceptor flows due to the flow of the reaction gas. 4 can generate a rotational force.

  In the chemical vapor deposition apparatus 1 according to the embodiment, the position E of the tip opening 7d of the nozzle tube 7a is set to coincide with the center C of the semiconductor wafer 3, and the reaction gas is set at the center C. Since the reactive gas flows evenly toward the outer peripheral edge of the semiconductor wafer 3, an even rotational force is generated on the blades 5 of the entire circumference of the susceptor 4A, and the susceptor 4A is smooth. Preferably rotated. However, the position E of the tip opening 7d of the nozzle tube 7 does not need to be exactly coincident with the center C, and may be set at the center including the vicinity of the center C. The central portion includes a range from the center C to a position displaced by ½ of the radius in the radial direction of the semiconductor wafer 3, depending on the diameter of the semiconductor wafer 3. If the position E of the tip opening 7d is displaced more than the above range in the outer peripheral direction of the semiconductor wafer 3, the rotational force acting on each blade 5 may become uneven and the susceptor 4 may not be rotated smoothly. There is.

  Further, as described above, the position of the tip of the nozzle tube 7a in the direction of the central axis S1 is set to the lower limit position of the heating area by the heater 6, but it is not necessary to limit to that position. Depending on the size of the diameter of the semiconductor wafer 3, the distance L from the surface 3a of the semiconductor wafer 3 is preferably set in the range of 1/2 to 5 times the diameter. When the distance L is smaller than the lower limit, the film thickness distribution is deteriorated. When the distance L is larger than the upper limit, the biasing pressure of the reactive gas contacting the surface 3a of the semiconductor wafer 3 is lowered, and a thin film having a predetermined thickness is obtained. Requires a large amount of reaction gas.

1 is a longitudinal sectional view showing a chemical vapor deposition apparatus according to an embodiment of the present invention. It is a longitudinal cross-sectional view which expands and shows the principal part of the chemical vapor deposition apparatus which concerns on one embodiment of this invention. It is a perspective view which shows an example of a susceptor. It is a perspective view which shows the other example of a susceptor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chemical vapor deposition apparatus 2 Reaction chamber 3 Semiconductor wafer 3a Surface 4 Susceptor 4a Wafer holder 4b, 4b1 Rim part 4e, 14d Annular groove 5 Blade 5a Blade member 6 Heater 7 Nozzle 7a Nozzle tube 8 Body 10 Flange 10a, 14e, 17c, 18 Exhaust port 11 Wall portion of load lock chamber 12 Partition wall of load lock chamber 13 Support leg (reaction chamber)
14 Cap 14a Supporting part 15 Supporting tool 16 Bearing 16a Ball C Center E Position of nozzle tip opening S1 Center axis

Claims (4)

A reaction chamber in which a reaction gas introduced from the outside to the inside can flow from the bottom to the top, and a susceptor rotatably provided in the reaction chamber and capable of mounting a semiconductor wafer on the lower surface side. A chemical vapor phase characterized in that a rotation generating means for rotating the susceptor in response to the flow of the reaction gas from the lower side to the upper side of the susceptor is provided at an outer peripheral portion of the region where the semiconductor wafer is mounted. Growth equipment.
  2. The chemical vapor deposition apparatus according to claim 1, further comprising a nozzle that blows and flows the reaction gas to a central portion of a surface of the semiconductor wafer mounted on the susceptor and facing downward. 3.   The susceptor is supported by a bearing interposed between an upper surface of the susceptor and a lower surface of a support portion of the reaction chamber, and is provided to be rotatable about an axis. Vapor growth equipment. The reaction chamber is provided with an exhaust port for discharging the reaction gas flowing in the reaction chamber and passing through the rotation generating means at a position facing the rotation generating means of the susceptor. Item 4. The chemical vapor deposition apparatus according to any one of Items 1 to 3.

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