JP2006140424A - Vapor growth apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the utility efficiency of a raw material to grow a high-quality compound semiconductor. <P>SOLUTION: The vapor growth apparatus comprises a rotatable substrate holder 2 for holding a substrate SB in a growth chamber 1, a means 3 for heating the substrate holder 2, a gas feeder 4 for feeding a reaction gas on the substrate SB, and an exhaust port 9 for exhausting the waste gas outside the growth chamber 1. The side wall 10 outer diameter of the growth chamber 1 is made approximately equal to that of the substrate holder 2 to form a reaction space RS in the growth chamber 1. A gas feeder 4 is composed of a first and second raw materials feeders 5, 6 remotely from each other, and a dopant gas feeder 8. An exhaust inlet pipe 11 having a square opening face 11a perpendicular to the normal on the turn locus of the substrate SB the lower side 11b parallel and proximate to the substrate holder 2 is connected to the exhaust port 9. The first and second raw materials feeders 5, 6, the dopant gas feeder 8, and the opening face 11a are so disposed to move the substrate SB to them one after another with rotation of the substrate holder 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal organic chemical vapor deposition apparatus (MOCVD apparatus) for growing a compound semiconductor.

  As a conventional vapor phase growth apparatus, for example, there is an MOCVD apparatus shown in FIG. 7 (see Patent Document 1). The MOCVD apparatus 100 includes a gas supply unit 106 including a first gas supply unit 102, a second gas supply unit 103, a carrier gas supply unit 104, and a dopant gas supply unit 105 on a growth chamber 101. A substrate holder 107 for mounting the substrate SB is rotatably provided in the chamber 101.

The substrate holding table 107 is provided with a heating means 108, and a gas cooling unit 109 is interposed between the gas supply unit 106 and the substrate holding table 107. Between the side wall of the growth chamber 101 and the substrate holder 107, an exhaust gas passage space 111 is provided for guiding various gases supplied on the substrate holder 107 to the discharge port 110.
The distance between the substrate holder 107 and the gas cooling unit 109 is large, and a relatively gentle temperature gradient is formed between them. Due to the temperature gradient, the downflow of various gases supplied from the gas supply unit 106, and the centrifugal force generated by the high-speed rotation of the substrate holding table 107, the substrate holding table 107 and the exhaust gas are formed in the growth chamber 101. A gas flow reaching the discharge port 110 through the passage space 111 is formed, and vapor phase growth is performed on the substrate SB.
JP 2001-506803 A

However, in the vapor phase growth apparatus described in Patent Document 1, various gases are always present on the substrate, in which the first source gas and the second source gas are mixed before reaching the substrate. The added compounds produced are also included, and these gases tend to rotate along with the substrate holder and stay on the substrate. As described above, when an additive compound that does not contribute to vapor phase growth stays in the vicinity of the substrate, the concentration of the source gas is lowered, and the utilization efficiency of the source material is deteriorated. Here, the additive compound is a compound in which two kinds of organic compounds are weakly bonded, or a compound in which another atomic group is bonded to an unsaturated bond atom (for example, phosphine (In) of trimethylindium (TMI)). (PH ₃ ) ₃ In · PH ₃ ) in which PH ₃ ) is bonded.

The additive compound does not contribute to the vapor phase growth of the substrate and may be mixed into the substrate as a foreign substance, leading to a decrease in quality.
Further, since the distance between the substrate holder and the gas supply unit is large, the ratio of the first raw material gas and the second raw material gas mixed with each other before reaching the substrate is relatively large. Since it does not contribute to phase growth, the utilization efficiency of raw materials is low.

Further, since the exhaust gas passage space is arranged around the substrate holding table, a considerable amount of the source gas flows so as to give up the upper surface of the source gas staying on the substrate and is led to the exhaust gas passage space, and is exhausted as it is. Therefore, there is a problem that the utilization efficiency of raw materials is low.
An object of the present invention is to solve the above problems in a vapor phase growth apparatus, and to provide a vapor phase growth apparatus that can grow a high-quality compound semiconductor with high utilization efficiency of raw materials.

  In the present invention, in order to solve the above-mentioned problem, a rotatable substrate holding table for holding a substrate, a heating means for heating the substrate holding table, and a substrate provided on a surface facing the substrate holding table are directed to the substrate. In the vapor phase growth apparatus having a gas supply unit for supplying the reaction gas and an exhaust port for discharging the exhaust gas in the growth chamber to the outside of the growth chamber, the inner diameter of the side wall of the growth chamber is substantially the same as the outer diameter of the substrate holder. A reaction space is formed in the growth chamber, and the gas supply unit is composed of at least a first source gas supply unit and a second source gas supply unit that are spaced apart from each other, and the normal direction of the rotation trajectory of the substrate and An exhaust introduction pipe having a rectangular opening surface that is orthogonal and has a side that is parallel to and close to the substrate holding table is connected to the exhaust port, and the first source gas supply unit, the second source gas supply unit, and The opening surface of the exhaust pipe is rotated by the rotation of the substrate holder. Plates first material gas supply unit, the second raw material gas supply unit, and arranged to sequentially transition the opening surface of the exhaust inlet pipe.

  According to this vapor phase growth apparatus, since the substrate passes through a state in which various source gases are stably distributed in the reaction space, the production of additional reactants is extremely small and the utilization efficiency of the source is high. In addition, various source gases that reach the substrate are exhausted every cycle, and additional compounds are always removed on the substrate to maintain a clean state, so that the use efficiency of the source is high and quality deterioration is suppressed. High quality compound semiconductors can be grown.

The gas supply unit includes a carrier gas supply unit that supplies a carrier gas over the entire region, and at least a first source gas supply unit and a second source gas supply unit that are inserted into the carrier gas supply unit at a distance from each other. Since the separation state of the raw material gases can be stably maintained, the production of the addition reaction product can be further reduced.
The height of the reaction space, the gas distribution state of the reaction space is a fresh carrier layer in which the carrier gas formed mainly on the gas supply unit side is present, the actual reaction layer formed on the substrate holder side, and the fresh carrier If the buffer layer is set to have a minimum three-layer structure necessary for the coexistence of the actual reaction layer and the actual reaction layer, the concentration of the source gas on the substrate is optimized, and the utilization efficiency of the source is improved.

If the side of the opening side of the exhaust pipe that faces the substrate holder is located at the interface between the actual reaction layer and the buffer layer, it is effective for vapor phase growth rather than exhausting all the gas distributed on the substrate. Since a reactive gas can accompany the substrate, the utilization efficiency of the raw material is improved.
When a second gas supply unit that supplies carrier gas or source gas or both carrier gas and source gas toward the substrate holding table is provided in a space formed between the exhaust introduction pipe and the substrate holding table, the carrier By supplying the gas, adhesion of the raw material to the exhaust introduction pipe can be prevented, and by supplying the raw material gas, the element once grown on the substrate can be prevented from being detached.

When the dopant gas supply unit is separated from the first source gas supply unit and the second source gas supply unit and disposed in the gas supply unit or the second gas supply unit, for example, the dopant gas supply location is set to the group III gas and the group V gas. It is possible to select the dopant gas supply order such as setting between the two or a group V gas, and to change the physical properties of the compound semiconductor.
Providing cooling means for cooling all of the components surrounding the reaction space except for the substrate holding table, it is possible to protect the components of the components and stably maintain the optimum temperature gradient. .

  The substrate holding table is a substrate holding cylinder for holding the substrate on the outer periphery of the cylinder, the growth chamber side walls are disposed close to both end faces of the substrate holding cylinder, and the reaction space is formed in an annular shape outside the substrate holding cylinder. A large number of substrates can be processed at once. In addition, when the substrate holder is disk-shaped, there may be some difference in the quality of the compound semiconductor due to the difference in peripheral speed between the vicinity of the center and the outer peripheral side. The quality of the compound semiconductor can be made uniform.

  According to the present invention, it is possible to realize a vapor phase growth apparatus that can grow a high-quality compound semiconductor with high utilization efficiency of raw materials.

FIG. 1 is a configuration diagram of a vapor phase growth apparatus showing an embodiment of the present invention, FIG. 2 is an explanatory view showing an example of a plane arrangement of a gas supply unit and an exhaust introduction pipe, and FIG. FIG. 4 is an explanatory diagram of a gas distribution state in the reaction space, and FIG. 4 is an explanatory diagram of the reaction space in which the growth chamber is developed in the rotation direction of the substrate holder.
The vapor phase growth apparatus includes a rotatable substrate holding table 2 on which a plurality of substrates SB are placed, a heating unit 3 for heating the substrate holding table 2, and a substrate holding device in a vertically long cylindrical growth chamber 1. A gas supply unit 4 that is provided on a surface facing the table 2 and supplies a reactive gas toward the substrate SB, and an exhaust port 9 that discharges the exhaust gas in the growth chamber 1 to the outside of the growth chamber 1 are provided.

The side wall 10 of the growth chamber 1 is set to have an inner diameter that is substantially the same as the outer diameter of the disk-shaped substrate holding table 2, and the growth chamber 1 includes the substrate holding table 2, the gas supply unit 4, and the side wall 10. The reaction space RS closed by the is formed.
The gas supply unit 4 includes a carrier gas supply unit 7 for supplying a carrier gas over the entire area, a first source gas supply unit 5 and a second source gas supply unit inserted in the carrier gas supply unit 7 at a distance from each other. 6 and a dopant gas supply unit 8.

The carrier gas supply unit 7 has a large number of nozzles 7b arranged concentrically and radially with respect to the substrate holder 2 and communicates with the nozzles 7b, and is connected to a supply pipe 7a at one place or several places. . As a result, the carrier gas is supplied to the substrate SB like a shower.
The first source gas supply unit 5 is provided with five pairs of supply pipes 5a and nozzles 5b arranged in the radial direction of the substrate holder 2, and the amount of source gas supplied from each nozzle 5b is a mass flow controller (not shown). It is adjusted by. Each nozzle 5 b is arranged so as to avoid interference with the nozzle 7 b of the carrier gas supply unit 7.

The second source gas supply unit 6 and the dopant gas supply unit 8 are configured in the same manner as the first source gas supply unit 5.
Usually, group III gas is supplied from the first source gas supply unit 5, and group V gas is supplied from the second source gas supply unit 6.
An exhaust introduction pipe 11 is connected to the exhaust port 9. The exhaust introduction pipe 11 has a rectangular opening surface 11a that opens into the reaction space RS. This opening surface 11a is orthogonal to the normal direction of the rotation locus of the substrate SB, and is in the radial direction of the disk-shaped substrate holding table 2. Is consistent with The lower side 11b of the opening surface 11a is parallel to the substrate holder 2 and close to the substrate holder 2, and is set to a height corresponding to an actual reaction layer RL described later.

The bottom plate 11c and the top plate 11d of the exhaust introduction pipe 11 are connected to the exhaust port 9 from the opening surface 11a with upward inclination.
A partition wall 14 is provided at the boundary between the exhaust introduction pipe 11 and the first source gas supply unit 5 to block the entire radial direction of the reaction space RS. The partition wall 14 also serves as a side plate of the exhaust introduction pipe 11. . A known exhaust gas abatement device (not shown) is connected to the rear stage of the exhaust port 9.

The first source gas supply unit 5, the second source gas supply unit 6, the dopant gas supply unit 8, and the opening surface 11 a of the exhaust introduction pipe 11 are arranged so that the substrate SB is rotated by the rotation of the substrate holder 2. The second raw material gas supply unit 6, the dopant gas supply unit 8, and the opening surface 11 a of the exhaust introduction pipe 11 are arranged so as to sequentially transition.
The various reaction gas supply units are arranged in such a manner that the third raw material gas supply unit is inserted depending on the object to be processed, the order of the reaction gas supplied to each gas supply unit is changed, or the same reaction gas is supplied twice. It is safe to change the setting.

Below the bottom plate 11 c of the exhaust introduction pipe 11, a second gas supply unit 12 that supplies carrier gas or source gas, or both carrier gas and source gas toward the substrate holder 2 is provided. The configuration of the nozzle 12b and the like of the second gas supply unit 12 is basically the same as that of the gas supply unit 4.
The heating means 3 includes a central heater 3a and an outer heater 3b in order to uniformly heat the vicinity of the center and the outer peripheral side of the disc-shaped substrate holding table 2 to make the temperature uniform.

  All the constituent elements surrounding the reaction space RS except the substrate holder 2 are provided with a cooling means 13. A first cooling pipe 13 a is provided above each nozzle of the gas supply unit 4, a second cooling pipe 13 b is provided between the second gas supply unit 12 and the exhaust introduction pipe 11, and in addition to this, the side wall 10. A cooling pipe (not shown) is provided on the outer periphery of the exhaust pipe 11 and the top surface of the top plate 11d of the exhaust introduction pipe 11 and is supplied with a refrigerant. The cooling means 13 protects the constituent members and makes it possible to stably maintain an optimum temperature gradient.

In this vapor phase growth apparatus, when the substrate holder 2 rotates, the substrate SB placed on the first source gas supply unit 5 and the second source gas supply unit 6 from the point A corresponding to the partition wall 14 shown in FIG. Transition to point B, which is in the middle, point C, which is between the second source gas supply unit 6 and dopant gas supply unit 8, and point D corresponding to the opening surface 11a of the exhaust introduction pipe 11.
Various source gases are stably distributed in the reaction space RS, and the substrate SB passes through this state. Therefore, the production of the additive compound is extremely small, and the utilization efficiency of the source is high. In addition, the various source gases that have reached the substrate are discharged every cycle, and the additional compounds on the substrate 2 are always removed to maintain a clean state, so that the use efficiency of the source material is high and the deterioration of the quality is suppressed. High quality compound semiconductors.

The gas supply unit 4 includes a carrier gas supply unit 7 for supplying a carrier gas over the entire area, a first source gas supply unit 5 and a second source gas supply unit inserted in the carrier gas supply unit 7 at a distance from each other. 6 and the dopant gas supply unit, and the separation state between the source gases can be stably maintained, so that the production of the additive compound can be further reduced.
Looking at the gas distribution state in the height direction of the reaction space RS when the reaction space RS is at an appropriate height, as shown in FIG. 4B, the raw material concentration is low and the carrier gas is mainly on the gas supply unit 4 side. A fresh carrier layer FL present in the substrate, an actual reaction layer RL having a high raw material concentration on the substrate holder 2 side, and a buffer layer BL that is minimum necessary for coexisting the fresh carrier layer FL and the actual reaction layer RL in the middle Has been.

In the fresh carrier layer FL and the actual reaction layer RL in this gas distribution state, the carrier gas is supplied over the entire surface of the gas supply unit 4, the flow rate of the carrier gas is less than the flow rate of the source gas, It is formed in the reaction space RS on condition that the gas has a flow rate sufficient to reach the substrate SB.
In this state, since the source gas concentration on the substrate 2 is optimized, the utilization efficiency of the source material is high, and a high-quality compound semiconductor can be grown.

The lower side 11b of the opening 11a of the exhaust introduction pipe 11 is located at the interface between the actual reaction layer RL and the buffer layer BL, and is effective for vapor phase growth rather than exhausting all the gas distributed on the substrate SB. Since a reactive gas can accompany the substrate SB, the utilization efficiency of the raw material is improved.
In addition, when the setting of the height of the reaction space RS is high as shown in FIG. 4A, the interval between the layers is widened and the concentration of the source gas in the vicinity of the substrate SB is reduced, and the material gas is discharged as it is without reaching the substrate. As a result, the raw material gas is increased and the utilization efficiency of the raw material is lowered.

  As the setting of the height of the reaction space RS is lowered, the reaction space RS will eventually be composed of only the actual reaction layer RL as shown in FIG. 4C, and the reaction space RS (= actual reaction layer RL). ), The source gas is agitated, and an addition reaction product is generated. Further, since the concentration distribution of the source gas is also made uniform in the height direction, as a result, the gas concentration in the vicinity of the substrate SB is reduced as compared with the case where an appropriate buffer layer BL is present.

  Since the second gas supply unit 12 for supplying the carrier gas or the raw material gas or both the carrier gas and the raw material gas to the substrate holding table 2 is provided between the exhaust introduction pipe 11 and the substrate holding table 2. By supplying the carrier gas, adhesion of the raw material to the exhaust introduction pipe 11 can be prevented, and by supplying the raw material gas, the element once grown on the substrate 2 can be prevented from being detached.

FIG. 5 is a block diagram of a vapor phase growth apparatus showing another embodiment of the present invention, and FIG. 6 is a bottom view of the vapor phase growth apparatus shown with a part broken away.
This vapor phase growth apparatus includes a growth chamber 51 in which a plurality of substrates SB are held on the outer circumference of a cylinder and rotatable, a substrate holding cylinder 52, a heating means 53 for heating the substrate holding cylinder 52, a substrate holding cylinder 52, A gas supply unit 54 that is provided on the opposite surface and supplies a reactive gas toward the substrate SB, and an exhaust port 59 that discharges the exhaust gas in the growth chamber 51 to the outside of the growth chamber 51 are provided.

The side wall 60 of the growth chamber 51 is disposed close to both side surfaces of the substrate holding cylinder 52, and the substrate holding cylinder 52 is constituted by the substrate holding cylinder 52, the gas supply unit 54 facing the substrate holding cylinder 52, and the side wall 60. An annular reaction space RS closed to the outside is formed.
The gas supply unit 54 includes a carrier gas supply unit 57 that supplies a carrier gas over the entire area, a first source gas supply unit 55 and a second source gas supply unit that are inserted in the carrier gas supply unit 57 at a distance from each other. 56 and a dopant gas supply unit 58. Usually, group III gas is supplied from the first source gas supply unit 55, and group V gas is supplied from the second source gas supply unit 56. The specific configuration of the nozzle of the gas supply unit 54 is substantially the same as that of the gas supply unit 4 shown in FIG. 1 and FIG.

  An exhaust introduction pipe 61 is connected to the exhaust port 59. The exhaust introduction pipe 61 has a rectangular opening surface 61 a that opens into the reaction space RS. The opening surface 61 a is orthogonal to the normal direction of the rotation locus of the substrate SB and coincides with the radial direction of the substrate holding cylinder 52. ing. The upper side 11b of the opening surface 61a is parallel to the substrate holding cylinder 52 and close to the substrate holding cylinder 52, and is set to a height corresponding to the actual reaction layer RL.

The bottom plate 61 c of the exhaust introduction pipe 61 is inclined downward, the top plate 61 d is substantially horizontal, and is continuous from the opening surface 61 a to the exhaust port 59.
A partition wall 64 extending in the radial direction of the reaction space RS is provided at the boundary between the exhaust introduction pipe 61 and the first source gas supply unit 55 and the dopant gas supply unit 58. A known exhaust gas abatement device (not shown) is connected to the rear stage of the exhaust port 59.

The first source gas supply unit 55, the second source gas supply unit 56, the dopant gas supply unit 58, and the opening surface 61 a of the exhaust introduction pipe 61 are arranged so that the substrate SB is rotated by the rotation of the substrate holding cylinder 52. The second source gas supply unit 56, the dopant gas supply unit 58, and the opening surface 61 a of the exhaust introduction pipe 61 are arranged so as to sequentially transition.
The various reaction gas supply units are arranged in such a manner that the third raw material gas supply unit is inserted depending on the object to be processed, the order of the reaction gas supplied to each gas supply unit is changed, or the same reaction gas is supplied twice. It is safe to change the setting.

Above the top plate 11 d of the exhaust introduction pipe 61, a second gas supply unit 62 that supplies carrier gas or source gas, or both carrier gas and source gas toward the substrate holding cylinder 52 is provided. The configuration of the nozzle and the like of the second gas supply unit 62 is also substantially the same as that of the gas supply unit 4 shown in FIGS.
All the constituent elements surrounding the reaction space RS except the substrate holding cylinder 52 are provided with a cooling means 63.

In this vapor phase growth apparatus, the reaction space RS is annular, but when the reaction space RS is expanded in the rotation direction of the substrate holding cylinder 52, the gas distribution is the same as that shown in FIGS. Since the source gas concentration on the SB is optimized, the raw material utilization efficiency is high, and a high-quality compound semiconductor can be grown.
Moreover, since the substrate holding cylinder 52 is cylindrical, it is possible to process a large number of substrates SB at a time, and it is possible to prevent the quality of the compound semiconductor from being varied depending on the mounting position of the substrate SB.

It is a block diagram of the vapor phase growth apparatus which shows one Embodiment of this invention. It is explanatory drawing which shows the example of arrangement | positioning on the plane of a gas supply part and an exhaust introduction pipe | tube. It is explanatory drawing of the reaction space which expand | deployed the growth chamber of the vapor phase growth apparatus in the rotation direction of the substrate holding stand. It is explanatory drawing of the gas distribution state of reaction space. It is a block diagram of the vapor phase growth apparatus which shows other embodiment of this invention. It is a bottom view of the vapor phase growth apparatus shown partially broken. It is a block diagram of the conventional vapor phase growth apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Growth chamber 2 Substrate holder 3 Heating means 4 Gas supply part 5 First raw material gas supply part 6 Second raw material gas supply part 7 Carrier gas supply part 8 Dopant gas supply part 9 Exhaust port 10 Side wall 11 Exhaust introduction pipe 11a Opening surface 12 Second gas supply unit 13 Cooling unit 14 Partition wall 51 Growth chamber 52 Substrate holding cylinder 53 Heating unit 54 Gas supply unit 55 First source gas supply unit 56 Second source gas supply unit 57 Carrier gas supply unit 58 Dopant gas supply unit 59 Exhaust port 60 Side wall 61 Exhaust introduction pipe 61a Opening surface 62 Second gas supply part 63 Cooling means 64 Partition BL Buffer layer FL Fresh carrier layer RL Actual reaction layer RS Reaction space SB Substrate

Claims (8)

In the growth chamber, a rotatable substrate holding table for holding the substrate, a heating means for heating the substrate holding table, a gas supply unit that is provided on a surface facing the substrate holding table and supplies a reactive gas toward the substrate, A vapor phase growth apparatus provided with an exhaust port for discharging exhaust gas in the growth chamber to the outside of the growth chamber,
A reaction space is formed in the growth chamber by making the inner diameter of the side wall of the growth chamber substantially the same as the outer diameter of the substrate holder,
The gas supply unit is composed of at least a first source gas supply unit and a second source gas supply unit that are arranged apart from each other,
An exhaust inlet pipe having a rectangular opening surface that is orthogonal to the normal direction of the rotation locus of the substrate and whose side on the substrate holder is parallel and close to the substrate holder is connected to the exhaust port;
The opening of the first source gas supply unit, the second source gas supply unit, and the exhaust introduction pipe is opened by opening the first source gas supply unit, the second source gas supply unit, and the exhaust introduction pipe by rotating the substrate holder. A vapor phase growth apparatus, which is arranged so as to sequentially transition with a surface.   The gas supply unit includes a carrier gas supply unit that supplies a carrier gas over the entire region, and at least a first source gas supply unit and a second source gas supply unit that are inserted into the carrier gas supply unit at a distance from each other. The vapor phase growth apparatus according to claim 1.   The height of the reaction space, the gas distribution state of the reaction space is a fresh carrier layer in which the carrier gas formed mainly on the gas supply unit side is present, the actual reaction layer formed on the substrate holder side, and the fresh carrier 3. The vapor phase growth apparatus according to claim 2, wherein the vapor phase growth apparatus is set so as to have a three-layer structure of a buffer layer which is at least necessary for coexistence of the layer and the actual reaction layer.   4. The vapor phase growth apparatus according to claim 3, wherein the side of the opening surface of the exhaust introduction pipe on the substrate holding table side is located at the interface between the actual reaction layer and the buffer layer.   In the space formed between the exhaust introduction pipe and the substrate holder, a second gas supply unit that supplies carrier gas or source gas or both carrier gas and source gas toward the substrate holder is provided. The vapor phase growth apparatus according to any one of claims 1 to 4, wherein the vapor phase growth apparatus is characterized.   The dopant gas supply unit is disposed in the gas supply unit or the second gas supply unit so as to be separated from the first source gas supply unit and the second source gas supply unit. The vapor phase growth apparatus described in 1.   The vapor phase growth apparatus according to any one of claims 1 to 6, further comprising a cooling unit that cools all of the components surrounding the reaction space except the substrate holder. The substrate holding table is a substrate holding cylinder for holding the substrate on the outer periphery of the cylinder, the growth chamber side walls are disposed close to both end faces of the substrate holding cylinder, and the reaction space is formed in an annular shape outside the substrate holding cylinder. The vapor phase growth apparatus according to claim 1, wherein the vapor phase growth apparatus is provided.

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