JP2015218340A - Vapor phase growth apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vapor phase growth apparatus capable of preventing a reactor from being deformed by heat in the reactor.SOLUTION: A vapor phase growth apparatus 1 comprises: a reactor 5 having a bottom wall 2, a side wall 3 and a top cover 4; a nozzle 7 for ejecting a raw material gas 6 into the reactor 5; a raw material gas supply pipe line 8 for penetrating the bottom wall 2 of the reactor 5 to supply the material gas 6 to the nozzle 7; a susceptor 10 for arranging the nozzle 7 in the center and mounting one or more substrates 9; heating means 11 provided in the reactor 5 and heating the substrates 9; and an opposite plate 12 arranged oppositely so as to be parallel to the upper surface of the susceptor 10. A heat shielding layer 16 for preventing the heat in the reactor 5 from being transferred is provided on the furnace inner side surface of the furnace wall of the reactor 5.

Description

  The present invention relates to a vapor phase growth apparatus.

  Conventionally, a semiconductor thin film is formed in a high-temperature reactor by, for example, MOCVD (metal organic chemical vapor deposition). The substrate to be deposited is arranged concentrically on a disk-shaped susceptor that rotates around a nozzle that ejects a source gas in the reaction furnace, and is heated by heating means provided at the lower part of the susceptor. It is common. In order to grow a semiconductor thin film on a substrate, the surface of the substrate is heated to a high temperature of about 1,000 ° C., and a source gas is supplied to the upper portion of the substrate to react components contained in the source gas (hereinafter, "Semiconductor film-forming reaction").

  According to the recent market development trend of semiconductors, a complicated structure in which various semiconductor films are stacked in a plurality of layers is required (for example, see Non-Patent Document 1). Since various semiconductor film formation reactions have suitable film formation temperatures, the surface temperature of the substrate is controlled to increase and decrease simultaneously with changing the source gas species. Here, FIG. 6 is a schematic cross-sectional view showing a configuration of a conventional vapor phase growth apparatus 101.

  As shown in FIG. 6, the conventional vapor phase growth apparatus 101 includes a disk-shaped bottom wall 102, a cylindrical side wall 103 erected from the outer peripheral end of the bottom wall 102, and an upper lid that closes the upper side of the side wall 103. 104, a nozzle 107 for ejecting a source gas 106 into the reactor 105, and a source gas supply pipe for supplying the source gas 106 to the nozzle 107 through the bottom wall 102. 108, a susceptor 110 on which the substrate 109 is placed, a heating unit 111 that heats the substrate 109 via the susceptor 110, and a susceptor 110 and a substrate above the susceptor 110. 109 and a counter plate 112 arranged so as to be parallel to the upper surface of 109.

  More specifically, the opposing plate 112 is a thin disk-shaped member, and is disposed above the susceptor 110 so as to be parallel to these in a state of being separated from the upper surfaces of the susceptor 110 and the substrate 109 by several mm. ing. Further, the distance between the susceptor 110 and the counter plate 112 (that is, the height from the upper surface of the susceptor 110 to the counter plate 112) is called a reaction channel width 113. The source gas 106 discharged from the nozzle 107 at the center in the reaction furnace 105 flows toward the outer periphery of the susceptor 110 through a space between the upper surface of the susceptor 110 and the counter plate 112.

  Here, the reaction channel width 113 is distorted (in other words, the reaction channel width 113 is different between the central portion and the outer peripheral end of the susceptor 110, or the reaction channel width 113 is different in the circumferential direction of the susceptor 110. , Etc.), the flow of the source gas 109 to be uniform is disturbed, and the minute turbulence causes a difference in the growth of the film formation, which greatly affects the quality of the film formation. Therefore, the reaction channel width 113 is precisely adjusted so as to be constant at a width suitable for the semiconductor film formation reaction.

  By the way, the inside of the reaction furnace 105 is generally heated to a high temperature by the heating means 111 for heating the substrate 109. For this reason, various cooling mechanisms are provided in the reaction furnace 105. Specifically, for example, as shown in FIG. 6, a cooling water pipe 114 is embedded inside the bottom wall 102, the side wall 103, and the upper lid 104 constituting the reaction furnace 105, and a coolant such as cooling water is flowed. A method of performing breakage of the furnace wall and temperature control of the furnace wall is generally known (see, for example, Patent Document 1).

Patent Document 2 discloses a metal organic vapor phase growth furnace provided with a water cooling device in order to control the temperature of the source gas.
Furthermore, Patent Document 3 discloses a vapor phase growth apparatus that includes a plurality of cooling tanks arranged concentrically and can easily reduce the temperature gradient of the temperature distribution on the opposing plate.

JP2011-057526A Japanese Patent No. 5042053 JP 2008-195995 A

Journal of Applied Physics, Vol. 81, No. 6 (June 2012)

  Incidentally, as shown in FIG. 6, when the semiconductor thin film is grown on the substrate 109, the temperature in the reaction furnace 105 (that is, the furnace atmosphere side of the furnace wall) is high. On the other hand, the cooling water piping 114 is embedded and the inside of the furnace wall cooled by the coolant and the outside of the reaction furnace 105 (that is, the outside air side of the furnace wall) are relatively cold. In this way, a large temperature difference occurs between the inside (furnace atmosphere side) and the outside (outside air side) of the furnace wall constituting the reaction furnace 105, so that expansion and contraction occur between the outside and inside of the furnace wall. There was a problem that a difference occurred and the furnace wall of the reaction furnace was curved.

  FIG. 7 is a schematic cross-sectional view showing the curved state of the furnace wall of the conventional vapor phase growth apparatus 101 when the inside of the reaction furnace is in a high temperature state. As shown in FIG. 7, when the inside of the reaction furnace 105 is hot, the bottom wall (bottom plate) 102 having a large area warps in a direction in which the central portion is lifted upward and in a direction in which the outer peripheral end is lowered downward. Will be added. Here, each component in the reaction furnace 105 is connected and fixed to any furnace wall constituting the reaction furnace 105. Specifically, as shown in FIG. 7, the source gas supply pipe 108 and the fixing portion near the center of the susceptor 110 are fixed near the center of the bottom wall (bottom plate) 102 having a large area. Therefore, when the inside of the reactor is hot, the bottom wall 102 is warped, so that the center side of the nozzle 107 and the susceptor 110 connected to the source gas supply pipe 108 is lifted remarkably upward than other components. Will be. That is, there has been a problem that the deformation of the furnace wall leads to a decrease in positional deviation and dimensional accuracy of the in-furnace parts.

  In addition, the temperatures suitable for the semiconductor film formation reaction are different from each other. Generally, since the temperature is repeatedly increased and decreased in the reaction furnace, it has been clarified that the deformation of the reaction furnace deteriorates with time.

  Conventionally, the size of the substrate itself is small, and the number of substrates on which films are formed simultaneously is small. For this reason, the size of the reactor itself was small, and the displacement and deformation of the nozzle and susceptor due to distortion of the reactor wall of the reactor were negligible.

  However, in recent years, with the increase in the size of the substrate and the increase in the number of processed sheets, the reaction furnace has also been increased in size. This makes it impossible to ignore the effects of nozzle and susceptor displacement and deformation, leading to distortion of the nozzle opening and reaction channel width, and distortion at the center of the reactor bottom wall that does not affect film quality (lifting). There is a problem that the tolerance value (specifically, for example, 1.0 mm in a 400 mm reactor) is greatly exceeded.

  This invention is made | formed in view of the said situation, Comprising: It aims at providing the vapor phase growth apparatus which can prevent the deformation | transformation of the reaction furnace by the heat | fever in a reaction furnace.

The invention according to claim 1 is a reaction furnace having a bottom wall, a cylindrical side wall standing from an outer peripheral end of the bottom wall, and an upper lid that closes an opening above the side wall;
A nozzle for injecting a raw material gas into the reaction furnace;
A source gas supply pipe for supplying a source gas to the nozzle through the furnace wall of the reactor;
A susceptor disposed around the nozzle and on which one or more substrates are placed;
A heating means provided in the reaction furnace for heating the substrate;
A vapor phase growth apparatus comprising: a counter plate disposed opposite to the upper surface of the susceptor,
The vapor phase growth apparatus is characterized in that a heat shield layer that inhibits heat transfer in the reaction furnace is provided on a furnace inner surface of a furnace wall of the reaction furnace.

  The invention according to claim 2 is the vapor phase growth apparatus according to claim 1, wherein the heat shield layer is constituted by a heat shield member including a cooling means.

  The invention according to claim 3 is characterized in that the heat shield member has a laminated structure and includes a reflective layer that reflects heat in the reaction furnace to the inside of the furnace. It is a phase growth device.

  The invention according to claim 4 is the vapor phase growth apparatus according to any one of claims 1 to 3, wherein the heat shield layer is provided at least on a furnace inner surface of the bottom wall. is there.

  The invention according to claim 5 is characterized in that the heat shield layer is provided so that the furnace inner surface of the furnace wall and the heat shield layer do not come into contact with each other. The vapor phase growth apparatus according to item.

  The invention according to claim 6 is the gas phase according to any one of claims 1 to 5, wherein a coverage of the bottom wall inside the furnace by the heat shielding layer is 80% or more. It is a growth device.

  The invention according to claim 7 is the vapor phase growth apparatus according to any one of claims 1 to 6, wherein the thermal barrier layer can be divided into a plurality of regions.

  According to the vapor phase growth apparatus of the present invention, a heat shield layer that inhibits heat transfer in the reaction furnace is provided on the inner surface of the furnace wall of the reaction furnace. This thermal barrier layer allows the temperature difference between the furnace inner surface and the furnace outer surface of the furnace wall to be within the required range, so that the reaction furnace by the heat in the reaction furnace (that is, the furnace wall constituting the reaction furnace) Can prevent deformation.

It is a cross-sectional schematic diagram which shows the structure of the vapor phase growth apparatus which is one Embodiment to which this invention is applied. It is a top view which shows an example of the structure of the thermal-insulation layer which coat | covers the bottom wall which comprises the vapor phase growth apparatus of this embodiment. It is sectional drawing which shows an example of the thermal insulation member which comprises the thermal insulation layer in the vapor phase growth apparatus of this embodiment. It is a top view which shows the modification of the structure of the heat shield layer in the vapor phase growth measure of this embodiment. It is sectional drawing which shows the modification of a structure of the heat-shielding member in the vapor phase growth means of this embodiment. It is a cross-sectional schematic diagram which shows the structure of the conventional vapor phase growth apparatus. It is a cross-sectional schematic diagram which shows the curved state of the furnace wall when the inside of the reaction furnace becomes a high temperature state of the conventional vapor phase growth apparatus.

Hereinafter, a vapor phase growth apparatus according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

First, the structure of the vapor phase growth apparatus which is one embodiment to which the present invention is applied will be described. FIG. 1 is a schematic cross-sectional view showing a configuration of a vapor phase growth apparatus according to an embodiment to which the present invention is applied.
As shown in FIG. 1, the vapor phase growth apparatus 1 of the present embodiment includes a disk-shaped bottom wall 2, a cylindrical side wall 3 standing from the outer peripheral end of the bottom wall 2, and an opening above the side wall 3. A reaction furnace 5 having an upper lid 4 for closing the part, a nozzle 7 for injecting a raw material gas 6 into the reaction furnace 5, and a raw material gas supply pipe for supplying the raw material gas 6 to the nozzle 7 through the bottom wall 2 8, a susceptor 10 on which the substrate 9 is placed, a heater (heating means) 11 that heats the substrate 9, and an upper surface of the susceptor 10 and the substrate 9. And a counter plate 12 arranged so as to be parallel to each other.

More specifically, examples of the material of the bottom wall 2, the side wall 3, and the upper lid 4 that constitute the reaction furnace 5 include stainless steel, inconel, and hastelloy.
Although the magnitude | size of the bottom wall 2 is not specifically limited, The distance (namely, radius) from the center of a disk should just be the range of 300-500 mm, and the range of 350-450 mm is more preferable. In this case, an allowable value of distortion (lifting) at the center of the reactor bottom wall that does not affect the quality of film formation is about 1.0 mm.

  The nozzle 7 is disposed so as to be located substantially in the center of the in-furnace space of the reaction furnace 5. Further, the nozzle 7 has a jet outlet parallel to the upper surface of the susceptor 10 and the upper surface of the substrate 9 placed on the susceptor 10 and directed in the circumferential direction of 360 degrees. This nozzle 7 ejects the raw material gas 6 supplied from the outside of the reaction furnace 5 through the raw material gas supply pipe 8 while changing its direction in the horizontal direction by 90 degrees.

  The source gas supply pipe 8 is a cylindrical member made of a material such as stainless steel. The source gas supply pipe 8 penetrates through the bottom wall 2 and is connected and fixed to the bottom wall 2.

  The susceptor 10 is a disk-shaped member made of a material such as SiC-coated carbon or SiC bulk material. A nozzle 7 is disposed at the center of the susceptor 10, and a plurality of substrates 9 can be placed concentrically around the nozzle 7.

  The counter plate 12 is a thin disk-shaped member. The counter plate 12 is disposed above the susceptor 10 so as to be parallel to the susceptor 10. Further, the bottom surface of the counter plate 12 and the top surface of the susceptor 10 are separated by about several mm. Here, a space between the upper surface of the susceptor 10 and the bottom surface of the counter plate 12 becomes a reaction flow path 13. That is, the source gas 6 released from the nozzle 7 at the center in the reaction furnace 5 flows toward the outer periphery of the susceptor 10 through the reaction flow path 13 between the upper surface of the susceptor 10 and the counter plate 12. .

  On the other hand, the distance between the susceptor 10 and the counter plate 12 (that is, the height from the upper surface of the susceptor 10 to the bottom surface of the counter plate 12) is called the reaction flow path width W. This reaction channel width W is precisely adjusted so as to be uniform within the surface of the susceptor 10 so as to be a width suitable for the semiconductor film forming reaction.

  A torus-shaped space on the outer peripheral side of the susceptor 10 in the reaction furnace 5 serves as an exhaust gas buffer groove 14 for temporarily storing the raw material gas after the reaction before discharging, and functions to prevent drift of the exhaust gas. An exhaust port 15 is provided in the bottom wall 2 positioned below the exhaust gas buffer groove 14, and exhaust gas is discharged from the exhaust port 15 to the outside of the reaction furnace 5.

  As shown in FIG. 1, the vapor phase growth apparatus 1 according to the present embodiment includes a bottom wall 2, a side wall 3, and an upper lid 4 constituting the reaction furnace 5 inside the furnace inside the furnace wall. A heat shield layer 16 that inhibits heat transfer is provided.

Here, the coverage of the furnace inner surface of the furnace wall by the heat shield layer 16 is preferably 70% or more, and more preferably 80% or more.
In particular, as shown in FIG. 1, the vapor phase growth apparatus 1 according to the present embodiment has the source wall 8 and the susceptor 10 connected and fixed to the bottom wall 2. The coverage is preferably 80% or more, and more preferably 90% or more.

  FIG. 2 is a plan view showing an example of the configuration of the thermal barrier layer 16 that covers the bottom wall 2 that constitutes the vapor phase growth apparatus 1 of the present embodiment. As shown in FIG. 2, the heat shield layer 16 is configured by a heat shield member 17 disposed so as to cover the furnace inner surface of the bottom wall 2. The heat shield member 17 has a shape in which a plurality of lines are divided. Further, the heat shield member 17 is provided with a supply port 17a for supplying the refrigerant therein and an exhaust port 17b for discharging the refrigerant from the inside.

  By covering the bottom wall 2 with the heat shielding layer 15 having such a configuration, the coverage of the furnace inner surface of the bottom wall 2 becomes almost 100%. For example, the temperature inside the furnace of the reaction furnace 5 is increased by the heater 11. When the temperature rises, it is possible to prevent the heat in the reaction furnace 5 from being directly transferred to the furnace inner surface of the bottom wall 2.

  FIG. 3 is a cross-sectional view showing an example of the heat shield member 17 constituting the heat shield layer 16 in the vapor phase growth apparatus 1 of the present embodiment. As shown in FIG. 3, the heat shield member 17 has a laminated structure including a cooling means 20 composed of a stainless steel (SUS) pipe 18 and a cooling water 19 and a reflective layer 21. Since the heat shield member 17 includes the cooling means, it is possible to effectively inhibit the heat in the reaction furnace 5 from being transmitted to the furnace inner surface of the bottom wall 2. In addition, since the heat in the furnace of the reaction furnace 5 can be reflected to the inside of the furnace by the reflection layer 21, the heat in the reaction furnace 5 is prevented from being transmitted to the furnace inner surface of the bottom wall 2, and It is possible to improve the productivity by increasing the thermal efficiency.

  Furthermore, as shown in FIG. 3, a laying table 22 may be used when the heat shield layer 16 composed of the heat shield member 17 is disposed on the furnace inner surface of the furnace wall. By disposing the heat shield layer 16 via the laying base 22 in this way, an air layer is provided between the heat shield layer 16 and the furnace inner surface of the furnace wall. By providing this air layer, heat conduction from the heat shield layer 16 to the furnace inner surface of the bottom wall 2 can be inhibited.

  In addition, it is not limited to the structure using the installation base 22, You may arrange | position the thermal insulation layer 16 comprised from the thermal insulation member 17 directly on the furnace inner surface of a furnace wall. In this case, it is easy to adjust the temperature of the inner surface of the furnace wall by controlling the temperature of the cooling water, and it is possible to efficiently keep the same temperature as the outside and prevent the furnace wall from being deformed efficiently.

By the way, as shown in FIGS. 6 and 7, in the conventional vapor phase growth apparatus 101, for example, when the film forming temperature is set to 1000 ° C., the heater temperature is about 1,100 degrees. Here, since the heat shield layer 16 is not provided on the bottom wall 102, the surface temperature inside the furnace of the bottom wall 102 is about 300 degrees. On the other hand, the surface temperature of the bottom wall 102 outside the furnace is about 50 degrees.
For example, when the bottom wall 102 is made of a material SUS304 (thermal expansion coefficient: 1.8 × 10 ⁻⁵ / ° C.), the bottom wall is located at a position where the distance (ie, radius) from the center of the disk is 400 mm. There is a risk of distortion (lifting) of about 4 mm with respect to the center of 102 (see FIG. 7).

On the other hand, in the vapor phase growth apparatus 1 of the present embodiment, for example, when the film forming temperature is 1000 ° C., the heater temperature is about 1,100 degrees. Here, as shown in FIGS. 1 and 3, the temperature of the surface 16 a inside the furnace of the heat shield layer 16 provided on the surface of the bottom wall 2 is about 300 degrees. On the other hand, the temperature of the outer surface 16b of the heat shield layer 16 is about 50 degrees. Furthermore, the surface temperature inside the furnace of the bottom wall 2 is about 40 degrees. On the other hand, the surface temperature of the bottom wall 2 outside the furnace is about 30 degrees.
For example, when the bottom wall 2 is made of the material SUS304 (thermal expansion coefficient: 1.8 × 10 ⁻⁵ / ° C.), when the distance from the center of the disk (that is, the radius) is about 400 mm, the bottom wall The distortion (lifting) with respect to the center of 2 can be suppressed to less than 0.2 mm.
When the coverage of the blocking layer 16 on the bottom wall 2 is 90%, the distortion (lifting) is about 0.6 mm, and when 80%, the distortion (lifting) is about 1.0 mm, which is 80% or more. If it is a coverage, it can satisfy | fill less than 1.0 mm which is a value which a vapor phase growth apparatus can accept | permit.

  As described above, according to the vapor phase growth apparatus 1 of the present embodiment, the heat shield layer 16 that inhibits the heat transfer in the reaction furnace 5 is provided on the furnace inner surface of the furnace wall of the reaction furnace 5. It has become. Since the temperature difference between the furnace inner surface and the furnace outer surface of the furnace wall can be controlled by the heat shield layer 16 so as to be within a required range, the reaction furnace 5 (that is, the heat in the reaction furnace (that is, It is possible to prevent deformation of the furnace wall constituting the reaction furnace. Therefore, the quality of film formation can be maintained without degrading the positional deviation or dimensional accuracy of the in-furnace parts.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. According to the vapor phase growth apparatus 1 of the above-described embodiment, the growth surface of the film formation on the substrate 9 is the upper side of the substrate, but is not limited to this. From the viewpoint of preventing impurities from adhering to the substrate 9, the substrate 9 may be placed on the lower surface of the susceptor 10, and the growth surface of the film may be on the lower side of the substrate 9. Further, the raw material gas supply pipe 8 penetrating the bottom wall 2 may be provided so as to penetrate the upper lid 4. Further, the opposing plate 12 may be provided below the susceptor 10.

  Moreover, in the vapor phase growth apparatus 1 of the said embodiment, as shown in FIG. 2, although the case where the heat shielding layer 16 was an integral thing was demonstrated to the example, it is not limited to this. Specifically, for example, as shown in FIG. 4, the heat shield layer 26 may be configured by combining the heat shield units 27A to 27D divided into four parts.

  Moreover, it is good also as a structure which installs the independent heat shield layer in the surface inside the furnace of the target furnace wall while measuring the temperature in a reactor, grasping | ascertaining the temperature distribution of a furnace wall. Thereby, since the temperature of a cooling water can be controlled independently, the raise of the temperature of a furnace wall can be prevented with a higher precision. That is, the deformation of the furnace wall is prevented with higher accuracy.

  Further, the heat shield layer is not limited to the case where it is provided on the entire surface of the furnace wall. It is good also as a structure by which the heat shielding layer is provided only with respect to the location which needs to suppress a deformation | transformation of a furnace wall.

  Moreover, in the vapor phase growth apparatus 1 of the said embodiment, although the case where the thermal insulation member 17 was a laminated structure containing the cooling means 20 and the reflective layer 21 was demonstrated as an example, it is not limited to this structure. For example, it may be a single layer structure consisting only of cooling means. Further, for example, as shown in FIG. 5, a heat insulating member 37 having a laminated structure in which a layer made of a heat insulating material 33 is further included and the cooling means 20 is embedded in the heat insulating material 33 may be used.

DESCRIPTION OF SYMBOLS 1 ... Vapor growth apparatus 2 ... Bottom wall 3 ... Side wall 4 ... Top cover 5 ... Reactor 6 ... Source gas 7 ... Nozzle 8 ... Source gas supply piping 9 ... Substrate 10 ... Susceptor 11 ... Heater (heating means)
12 ... Counter plate 13 ... Reaction channel 14 ... Exhaust gas buffer groove 15 ... Exhaust port 16, 26 ... Heat shield layer 17, 37 ... Heat shield member 18 ... Piping 19 ... Cooling water 20 ... Cooling means 21 ... Reflective layer 33 ... Heat insulating material W ... Reaction channel width

Claims (7)

A reactor having a bottom wall, a cylindrical side wall erected from an outer peripheral end of the bottom wall, and an upper lid that closes an opening above the side wall;
A nozzle for injecting a raw material gas into the reaction furnace;
A source gas supply pipe for supplying a source gas to the nozzle through the furnace wall of the reactor;
A susceptor disposed around the nozzle and on which one or more substrates are placed;
A heating means provided in the reaction furnace for heating the substrate;
A vapor phase growth apparatus comprising: a counter plate disposed opposite to the upper surface of the susceptor,
A vapor phase growth apparatus characterized in that a thermal barrier layer that inhibits heat transfer in the reaction furnace is provided on a furnace inner surface of a furnace wall of the reaction furnace.   2. The vapor phase growth apparatus according to claim 1, wherein the heat shield layer is constituted by a heat shield member including a cooling unit.   3. The vapor phase growth apparatus according to claim 2, wherein the heat shielding member has a laminated structure and includes a reflective layer that reflects heat in the reaction furnace to the inside of the furnace.   4. The vapor phase growth apparatus according to claim 1, wherein the heat shield layer is provided at least on a furnace inner surface of the bottom wall. 5.   5. The vapor phase growth apparatus according to claim 1, wherein the heat shield layer is provided so that a furnace inner surface of the furnace wall does not contact the heat shield layer. 6. .   The vapor phase growth apparatus according to any one of claims 1 to 5, wherein a coverage of the bottom wall of the bottom wall by the heat shield layer is 80% or more.   The vapor phase growth apparatus according to claim 1, wherein the heat shielding layer can be divided into a plurality of regions.

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