Patent Application
20150259799
This application claims the benefit of Japanese Patent Application No. 2014-047790, filed on Mar. 11, 2014, in the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference.
The present disclosure relates to a vertical heat treatment apparatus which forms films on all of a plurality of substrates, a method of operating the vertical heat treatment apparatus, and a non-transitory computer-readable recording medium storage medium for storing a program for performing the operating method.
In general, a film forming treatment such as ALD (Atomic Layer Deposition) or CVD (Chemical Vapor Deposition) is performed on a semiconductor wafer (hereinafter, referred to as a wafer) composed of a silicon substrate, etc. in order to fabricate a semiconductor product. The film forming treatment may be performed in a batch type vertical heat treatment apparatus for treating a plurality of wafers at a time. In this case, the wafers are moved and mounted onto a vertical wafer boat so that they are supported in the shape of shelves in multi-stages on the wafer boat. The wafer boat is carried (loaded) into an evacuable reaction chamber (reaction tube) from below, and a variety of gases are then supplied into the reaction chamber in a state that the interior of the reaction chamber is airtightly sealed, thereby performing the film forming treatment on the wafers. A method of performing the CVD with wafers mounted on the wafer boat is known as prior art.
Dummy wafers are held and supported in upper and lower sides of the wafer boat, and a plurality of wafers (for convenience of explanation, which may be described as product wafers), which are target substrates for manufacturing the semiconductor products, is held and supported such that the product wafers are inserted between dummy wafers located in the upper and lower sides of the wafer boat. In such a state, the wafer boat is carried into the reaction chamber as described above. As such, the reason why the dummy wafers are held and supported along with the product wafers in the wafer boat is to form films with high uniformity on the product wafers by smoothing the gas flow in a treatment chamber and by increasing uniformity of temperature among the product wafers, and is to prevent particles from being entrained on the product wafers when particles are produced from the wafer boat made of quartz. Unlike the product wafers, various films for forming the semiconductor products are not formed on surfaces of the dummy wafers, and thus convex and concave portions for forming wiring are not formed. Hereinafter, the dummy wafer may be described as a bare wafer.
As a semiconductor product is being miniaturized, the convex and concave portions are formed with high density on a surface of a product wafer and thus a surface area of the product wafer is gradually increasing. For this reason, in the film forming treatment, the amount of gas consumed by the product wafer is gradually increasing as compared with the amount (reacted amount) of processing gas consumed by a bare wafer. Therefore, for product wafers respectively supported in upper and lower sections of a wafer boat, a relatively large amount of processing gas is supplied by disposing bare wafers, which consumes a small amount of processing gas, in the vicinity of such product wafers, so that. However, a larger amount of processing gas is consumed by product wafers that are supported above and below than the product wafers, which are supported in a middle section of the wafer boat. In this case, the product wafers supported in a middle section of the wafer boat consume a relatively small supply amount of processing gas per wafer. As a result, there is a concern that the thickness of films formed by the processing gas among the product wafers may vary.
In order to control the distribution of the processing gas for the product wafers, it was suggested that a film forming treatment is performed by CVD with dummy wafers mounted in a wafer boat. In this case, the dummy wafers are made of silicon and have a surface area approximately equal to that of a product wafer. Further, it was suggested that the dummy wafers are reused by immersing the dummy wafers in a hydrofluoric acid solution after the film formation process, thereby removing the formed film. However, such a configuration requiring such wet etching is disadvantageous in that the dummy wafers should be transferred from the vertical heat treatment apparatus to another apparatus, thereby causing a need for a great deal of labor.
Some embodiments of the present disclosure provide a technique that can improve uniformity of the film thicknesses among the substrates and save labor for operating an apparatus when performing a film forming treatment by supplying a processing gas into a reaction chamber with a holding and supporting unit for holding and supporting a plurality of substrates in the shape of shelves loaded into the reaction chamber.
According to one embodiment of the present disclosure, there is provided a vertical heat treatment apparatus for performing a film forming treatment on a plurality of target substrates by heating the target substrates with a heating unit in a state that the target substrates are held and supported by a substrate holding and supporting unit in a vertical reaction chamber, each of the target substrates having a surface with convex and concave portions, the apparatus comprising: a gas supply unit that supplies a film forming gas into the reaction chamber; and gas distribution adjusting members made of quartz and installed to be positioned respectively above and below a region in which the plurality of target substrates held and supported by the substrate holding and supporting unit are disposed, wherein if S is a surface area per unit region of the gas distribution adjusting members and S0 is a surface area per unit region obtained by dividing a surface area of the target substrate by a surface area calculated based on an external dimension of the target substrate, a value obtained by dividing S by S0 (S/S0) is set to be 0.8 or more.
According to another embodiment of the present disclosure, there is provided a method of operating a vertical heat treatment apparatus for performing a film forming treatment on a plurality of target substrates by heating the target substrates with a heating unit in a state that the target substrates are held and supported by a substrate holding and supporting unit in a vertical reaction chamber, each of the target substrates having a surface with convex and concave portions, the method comprising supplying a film forming gas into the reaction chamber by using a gas supply unit in a state that gas distribution adjusting members made of quartz are positioned respectively above and below a region in which the plurality of target substrates held and supported by the substrate holding and supporting unit are disposed, wherein if S is a surface area per unit region of the gas distribution adjusting members and S0 is a surface area per unit region obtained by dividing a surface area of the target substrate by a surface area calculated based on an external dimension of the target substrate, a value obtained by dividing S by S0 (S/S0) is set to be 0.8 or more.
According to another embodiment of the present disclosure, there is provided a non-transitory computer-readable storage medium for storing a program used in a vertical heat treatment apparatus in order to perform the aforementioned method.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. Throughout the drawings, like reference numerals are used to designate like elements. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.
A first embodiment of the present disclosure will be described based on the accompanying drawings.
A lower end of the manifold 2 is open as a loading/unloading opening (furnace opening), and a peripheral portion of the opening 22 is formed integrally with a flange 23. In a lower portion of the manifold 2, a lid 25 made of, e.g., quartz, is installed to be opened and closed in a vertical direction by a boat elevator 26. The lid 25 airtightly closes the opening 22 on the lower surface of the flange 23 with a sealing member 24 such as an O-ring interposed therebetween. A rotating shaft 27 is installed to penetrate a central portion of the lid 25. A wafer boat 3 that is a substrate holding and supporting unit is mounted on an upper end of the rotating shaft with a stage 39 interposed therebetween.
An L-shaped first raw material gas supply pipe 40 is inserted through a sidewall of the manifold 2. At a leading end of the first raw material gas supply pipe 40, as shown in
Further, an L-shaped second raw material gas supply pipe 50 is inserted through the sidewall of the manifold 2. A second raw material gas supply nozzle 51 made of quartz is installed at a leading end of the second raw material gas supply pipe 50. The second raw material gas supply nozzle 51 extends upward in the reaction tube 11, is bent while extending upward and is installed in the plasma generating unit 60 described later. A plurality (large number) of gas discharge holes 51a are formed at a predetermined interval in a lengthwise direction of the second raw material gas supply nozzle 51. A gas can be approximately uniformly discharged from the respective gas discharge holes 51a in a horizontal direction. In addition, a base end of the second raw material gas supply pipe 50 is bifurcated into two branches so that a supply source 53 of NH3 (ammonia) gas that is a second raw material gas is connected to one branch of the second raw material gas supply pipe 50 via a supply device group 52, and a supply source 55 of N2 (nitrogen) gas is connected to the other branch of the second raw material gas supply pipe 50 via a supply device group 54.
Moreover, one end of a cleaning gas supply pipe 45 is inserted through a sidewall of the manifold 2. The other end of the cleaning gas supply pipe 45 is bifurcated into two branches which in turn are connected to a gas supply source 48 of F2 (fluorine) gas and a gas supply source 49 of HF (hydrogen fluoride) via supply device groups 46 and 47, respectively. Thus, a mixed gas of F2 and HF may be supplied as a cleaning gas into the reaction tube 11. The cleaning gas is not limited to a gas employing such fluorine gas or hydrogen fluoride gas as a major component, but may be, for example, a gas employing another fluorine compound as a major component. Furthermore, each of the supply device groups 42, 46, 47, 52 and 54 is comprised of a valve, a flow rate adjuster, and the like.
Further, the plasma generating unit 60 is provided on a portion of the sidewall of the reaction tube 11 in a height direction of the reaction tube. The plasma generating unit 60 is constructed in a manner that the vertically elongated opening 61 is formed by vertically cutting out the sidewall of the reaction tube 11 by a predetermined width and a vertically elongated compartment wall 62 made of, e.g., quartz, which is concave in cross section, is then airtightly welded on an outer wall of the reaction tube 11 to cover the opening 61. A region surrounded by the compartment wall 62 becomes a plasma generating region PS.
The opening 61 is formed to be sufficiently long in the vertical direction in order to cover all of wafers, which are held and supported by the wafer boat 3, in the height direction. Further, a pair of elongated plasma electrodes 63 facing each other in the lengthwise direction (vertical direction) is provided on outer surfaces of both sidewalls of the compartment wall 62. A high frequency power source 64 for plasma generation is connected to the plasma electrodes 63 via a power supplying line 65. Plasma can be generated by applying a high frequency voltage of, for example, 13.56 MHz to the plasma electrodes 63. An insulating protection cover 66 made of, for example, quartz is installed to cover the compartment wall 62 at the outside of the compartment wall 62.
Further, an exhaust port 67 is open in the manifold 2 to make the atmosphere in the reaction tube 11 be vacuum-exhausted. The exhaust port 67 is connected to an exhaust pipe 59, which has a vacuum pump 68 constituting a vacuum evacuating means for depressurizing and evacuating the interior of the reaction tube 11 to a desired degree of vacuum, and a pressure regulating unit 69 comprised of, for example, a butterfly valve. As shown in
Further, the vertical heat treatment apparatus 1 includes a control unit 100. The control unit 100 is comprised of, for example, a computer and configured to control the boat elevator 26, the heater 28, the supply device groups 42, 46, 47, 52 and 54, the high frequency power source 64, the pressure regulating unit 69, and the like. More specifically, the control unit 100 includes a memory unit configured to store sequence programs for performing a series of treatment steps, which will be described later, carried out in the reaction tube 11, a means for reading out instructions of the respective programs and outputting control signals to the respective components, and the like. Moreover, the programs are stored in the control unit 100 in a state that they are stored in a storage medium such as a hard disk, a flexible disk, a compact disk, a magneto-optical (MO) disk, a memory card or the like.
Next, the wafer boat 3 will be further explained. The wafer boat 3 is made of quartz, and includes a ceiling plate 31 and a bottom plate 32 which are placed parallel to each other during a film forming treatment. The ceiling plate 31 and the bottom plate 32 are respectively connected to one end and the other end of each of three pillars 33 extending in the vertical direction. Supports 34 (see
In the first embodiment, wafers 10 and wafers 71 are mounted in the slots. The wafer 10 is a product wafer for manufacturing a semiconductor product described in the BACKGROUND, and is made of, for example, a silicon substrate. As shown in
The wafer 71 is a wafer made of quartz (hereinafter, referred to as a quartz wafer). The quartz wafer 71 is configured to have a contour corresponding to that of the wafer 10 when seen from the top, so as to be mounted in the wafer boat 3. In order to prevent the wafer from breaking during handling, the thickness of the quartz wafer 71 is, for example, slightly greater than that of the wafer 10 and is, for example, 2 mm. A longitudinal sectional side view of the quartz wafer 71 is shown in an enlarged scale within a dotted-line circle depicted at the end of a dotted-line arrow of
A surface area per unit region, which is obtained by dividing the surface area of the wafer 10 by a surface area calculated based on an external dimension of the wafer 10, is referred to as S0. The surface area obtained based on the external dimension is a virtual surface area obtained by assuming that the surfaces of the wafer 10 are flat surfaces without considering concave portions 37 of the surface of the wafer 10. That is, a value obtained by dividing the actual surface area of the wafer 10 by the virtual surface area is the surface area per unit region S0. The surface area of the wafer, which is referred to herein, is the area of a top side (front side) of the wafer+the area of a bottom side (back side) of the wafer. In addition, a surface area per unit region, which is obtained by dividing the surface area of the quartz wafer 71 by a surface area calculated based on external dimension of the quartz wafer 71, is referred to as S. In the same manner as the wafer 10, the surface area obtained based on the external dimension of the quartz wafer 71 is a virtual surface area obtained by assuming that the front and back sides of the quartz wafer 71 are flat surfaces without considering concave portions formed in the front and back sides of the quartz wafer 71. In order to adjust a gas distribution in the vertical direction in the wafer boat 3 as described later, S/S0 is set to be 0.8 or more. In this example, the quartz wafer 71 is configured such that S/S0=1.
As shown in
Next, the film forming treatment performed in the vertical heat treatment apparatus 1 will be described. First, the wafer boat 3 mounted with the group of wafers 10 inserted between the above and below quartz wafers 71 as described above is lifted from below and is carried (loaded) into the reaction tube 11 which was previously set to a predetermined temperature. The lower opening 22 of the manifold 2 is closed by the lid 25, thereby hermetically sealing the interior of the reaction tube 11.
Then, the interior of the reaction tube 11 is vacuum-evacuated by the vacuum pump 68 to a predetermined degree of vacuum. Subsequently, the pressure in the reaction tube 11 becomes, for example, 665.5 Pa (5 Torr), and DCS gas and N2 gas are supplied into the reaction tube 11 from the first raw material gas supply nozzles 41, for example, respectively at flow rates of 1,000 sccm and 2,000 sccm, for example, for three seconds in a state that the high frequency power source 64 is turned off. Thus, molecules of the DCS gas are adsorbed onto a surface of each of the wafers 10 held and supported in the shape of shelves in the rotating wafer boat 3 (Step S1).
Thereafter, the supply of the DCS gas is stopped. The N2 gas is continuously supplied into the reaction tube 11 and the pressure in the reaction tube 11 becomes, for example, 120 Pa (0.9 Torr), thereby purging the interior of the reaction tube 11 with the N2 gas (Step S2). Then, while the pressure in the reaction tube 11 becomes, for example, 54 Pa (0.4 Torr), NH3 gas and N2 gas are supplied into the reaction tube 11 from the second raw material gas supply nozzle 51, for example, respectively at flow rates of 5,000 sccm and 2,000 sccm, for example, for 20 seconds in a state that the high frequency power source 64 is turned on (Step S3). Thus, active species, such as N radicals, H radicals, NH radicals, NH2 radicals, and NH3 radicals, react with the molecules of the DCS gas, thereby generating a SiN film 38 shown in
Thereafter, the supply of the NH3 gas is stopped. The N2 gas is continuously supplied into the reaction tube 11 and the pressure in the reaction tube 11 becomes, for example, 106 Pa (0.8 Torr), thereby purging the interior of the reaction tube 11 with the N2 gas (Step S4).
The status of the wafer 10 and quartz wafer 71 when the DCS gas is supplied during the film forming treatment will be described using a schematic view of
Similarly to the wafers 10 held and supported in the middle section, wafers having large surface areas, i.e., quartz wafers 71, exist in the vicinity of the wafers 10 held and supported in upper and lower sections of the wafer boat 3. Thus, the molecules 70 supplied to the upper and lower sections of the wafer boat 3 are consumed such that they are distributed with high uniformity on the wafers 10 and the quartz wafers 71. That is, the adsorption amount of molecules 70 onto the quartz wafer 71 is relatively large due to the large surface area of the quartz wafer 71. Thus, it is possible to prevent excessive molecules 70 from being supplied to the wafer 10, thereby suppressing an excessive absorption amount of molecules 70 per sheet of the wafer 10.
As illustrated in
After the process is terminated by repeating Steps S1 to S4 200 times as described above, the wafer boat 3 is unloaded from the reaction tube 11. After the wafers 10 for which the film formation treatment is terminated are taken out from the wafer boat 3, the wafer boat 3 is again loaded into the reaction tube 11 and the opening 22 is closed. The interior of the reaction tube 11 is vacuum-evacuated and is set to a predetermined pressure, while setting the interior temperature of the reaction tube 11 to, for example, 350 degrees C. Then, the aforementioned cleaning gas composed of F2 and HF is supplied into the reaction tube 11. Accordingly, the SiN film 38 formed in the reaction tube 11 and on the wafer boat 3 and quartz wafers 71 are etched and removed from the reaction tube 11 through entrainment in an exhaust stream. Thereafter, the supply of the cleaning gas is stopped, and the wafer boat 3 is unloaded from the reaction tube 11. Then, subsequent wafers 10 are mounted in the wafer boat 3, and the film forming treatment is performed on the subsequent wafers 10 according to Steps S1 to S4.
A curve indicated by a solid line in
As the surface areas of the quartz wafers 71 become larger, it is believed that the supply of a gas to the wafers 10 at the upper and lower sections of the wafer boat 3 can be suppressed. In
Further, since the quartz wafer 71 is made of quartz, corrosion, which is caused by the cleaning gas including the fluorine gas or a gas composed of a fluorine compound, is suppressed as compared to a wafer made of Si. For this reason, the quartz wafer 71 can be repeatedly used in the film forming treatment as described above. Further, since it is unnecessary to transfer the quartz wafer 71 to an apparatus for performing wet etching in order to perform cleaning, it is possible to save labor for operating such an apparatus.
Meanwhile, there is a case that the film forming treatment is performed with a relatively small number of wafers 10 held and supported in the wafer boat 3. In this case, for example, the film forming treatment is performed by holding and supporting the wafers 10 as shown in
The bare wafers 72 are held and supported in slots respectively at the upper and lower sections of the wafer boat 3 so that the group of quartz wafers 71 and the group of wafers 10 are inserted between the bare wafers. The bare wafers 72 are mounted to prevent disturbance of the flow of a gas in the reaction tube 11 or distortion of the temperature distribution in the wafers 10. As such, any one of the wafers 10, the quartz wafers 71 and the bare wafers 72 is held and supported in each of Slot Nos. 1 to 120.
Similarly to
As explained in
In the vertical heat treatment apparatus 1 according to the second embodiment, convex and concave portions are formed in an upper region 81 including a ceiling surface and an upper circumferential surface of the reaction tube 11 and in a lower region 82 that is a lower circumferential surface of the reaction tube 11, in order to increase the surface areas. The upper and lower regions 81 and 82 are inner circumferential surfaces of the reaction tube 11. When the wafer boat 3 is accommodated in the wafer boat 3, the lower region 82 includes a region lower than the group of wafers 10 mounted in the wafer boat 3. The convex and concave portions of the upper and lower regions 81 and 82 are formed, for example, by means of a sandblasting treatment or a chemical solution treatment. If the sandblasting treatment is performed, arithmetic average roughness (Ra) is, for example, 0.4 to 4.0 μm. If the chemical solution treatment is performed, the arithmetic average roughness (Ra) is, for example, 0.3 to 4.0 μm. Convex and concave portions may be formed also in the quartz wafer 71 according to the first embodiment by means of the sandblasting or chemical solution treatment. Further, in the same manner as the quartz wafer 71, convex and concave portions may be formed in the reaction tube 11 by laser processing.
By forming roughness (convex and concave portions) as described above, the upper and lower regions 81 and 82 serve to adjust supply distribution of a gas in the same manner as quartz wafer 71 according to the first embodiment. To this end, if a surface area per unit region for each of the upper and lower regions 81 and 82 is S, the convex and concave portions are formed such that the relationship S/S0 with the surface area S0 per unit region of the wafer 10 becomes 0.8 or more as in the first embodiment. The surface area of each of the upper and lower regions 81 and 82 is a surface area of a surface facing the treatment space into which a gas is supplied. To further explain the surface area S per unit region of the upper region 81 in detail as an example, it is assumed that the upper region 81 has no convex and concave portions and is cut to obtain a segment having an area A equal to the area of a region surrounded by the contour of the wafer 10. If the surface area of a surface of the cut segment facing the treatment space in the reaction tube 11 is B, S is B/A. The surface area B is a surface area measured under the assumption that there are convex and concave portions. The surface area S of the lower region 82 is calculated in the same manner.
In the inner circumferential surface of the reaction tube 11, a region interposed between the upper and lower regions 81 and 82 is referred to as a middle region 83. The middle region 83 is positioned around an outer periphery of the group of wafers 10 when the wafer boat 3 is loaded into the reaction tube 11. The middle region 83 is configured to have a smooth surface without performing the sandblasting or chemical solution treatment. That is, the roughness of the middle region 83 is smaller than that of the upper and lower regions 81 and 82.
The film forming treatment and cleaning treatment are performed also in the vertical heat treatment apparatus 1 according to the second embodiment in the same manner as the first embodiment. By forming the rough inner circumferential surface of the reaction tube 11 as described above, a gas supplied into upper and lower sections of the wafer boat 3 during the film forming treatment is consumed in the upper and lower regions 81 and 82. Accordingly, as in the first embodiment, it is possible to prevent the gas from being excessively supplied to the wafers 10 held and supported at the upper and lower sections of the wafer boat 3. As such, the upper and lower regions 81 and 82 of the reaction tube 11 perform the same function as the quartz wafers 71 of the first embodiment as described above. Hence, unlike the first embodiment, the bare wafers 72, instead of the quartz wafers 71, are detachably held and supported by the wafer boat 3 in this embodiment. That is, the group of wafers 10 is held and supported such that it is inserted between above and below bare wafers 72. Unlike a case using the quartz wafers 71, the bare wafers 72 are removed from the wafer boat 3 during the cleaning treatment.
Similarly to
A region formed with the roughness above the group of wafers 10 in the reaction tube 11 may be either of the ceiling surface and the side circumferential surface. For a region below the group of wafers 10 in the reaction tube 11, the roughness formation is not limited to forming the roughness in the side circumferential surface but the roughness may be made in a surface of the bottom plate of the reaction tube 11, i.e., a surface of the lid 25.
In the third embodiment, a vertical heat treatment apparatus 1 similar to that of the first embodiment is used, but the roughness described in the second embodiment is not formed, for example, in the inner surface of the reaction tube 11. Instead, the surface of each of the ceiling plate 31 and the bottom plate 32 of the wafer boat 3 is roughened as in the upper and lower regions 81 and 82 of the reaction tube 11 described in the second embodiment, resulting in the surface area S per unit region thereof/the surface area per unit region S0 of the wafer 10≧0.8.
To explain the surface area S per unit region of the ceiling plate 31 of the wafer boat 3 in detail, it is assumed that the ceiling plate 31 has no convex and concave portions and is cut to obtain a segment having an area A equal to that of a region surrounded by the contour of the wafer 10. If the surface area of a surface of the cut segment which faces the treatment space in the reaction tube 11 is B, S is B/A. Since both upper and lower surfaces of the ceiling plate 31 face the treatment space, the surface area B is the sum of surface areas of the upper and lower surfaces. The surface area S per unit region of the bottom plate 32 of the wafer boat 3 is calculated in the same manner. The lower surface of the bottom plate 32 is covered by a stage 39 (see
The graph of
In the fourth embodiment, the same vertical heat treatment apparatus as that of the first embodiment is used, and the wafer boat 3 is configured in the same manner as the first embodiment. In the fourth embodiment, wafers 10 and bare wafers 76 are held and supported in the wafer boat 3. The bare wafer 76 is configured to have the same shape as the bare wafer 72 but is made of quartz, instead of Si. When the surface area S per unit region of the bare wafer 76 is obtained in the same manner as the first embodiment, the relationship with the surface area S0 per unit region of the wafer 10 becomes S/S0<1.0.
As shown in
Also in the fourth embodiment, the filming forming treatment and the cleaning treatment are performed in the same manner as the other embodiments. Since the plurality of bare wafers 76 are mounted in the middle section of the wafer boat 3, the consumption amount of the gas is reduced in the vicinity of the middle section during the film forming treatment. Therefore, the supply amount of a gas is increased for the wafers 10 mounted in slots close to the slots with the bare wafers 76 mounted.
In
Since the bare wafers 76 are made of quartz as described above, they are loaded along with the wafer boat 3 into the reaction tube 11 during the cleaning treatment, as in the first embodiment. In the same manner as the quartz wafers 71 of the first embodiment, the bare wafers 76 may be fixed or detachably attached to the wafer boat 3. Although the plurality of bare wafers 76, which are plate-shaped members between the target substrates, are mounted in the middle section of the wafer boat 3 in order to sufficiently improve the supply distribution of a gas, only one bare wafer 76 may be mounted.
The fourth embodiment may be combined with the other embodiments. Specifically, the bare wafers 76 are used as the wafers mounted respectively in the plurality of slots at the upper and lower sections of the wafer boat 3 in
Although the vertical heat treatment apparatus 1 is configured to perform ALD, the present disclosure may be applied to a batch type treatment apparatus for forming a film by supplying a gas. Thus, the present disclosure may be applied to a vertical heat treatment apparatus for performing CVD. Further, the respective embodiments described above may be implemented in combination with one another. For example, in the first embodiment, the film forming treatment may be performed using the reaction tube 11 formed with the roughness as described in the second embodiment. In the first to third embodiments, the bare wafers 76 may be disposed between a group of wafers 10 and a group of wafers 10 by applying the fourth embodiment. Further, in the second and third embodiments, the film forming treatment may be performed by mounting the bare wafers 76 instead of the bare wafers 72.
Meanwhile, it may be considered that wafers 10 per every lot carried into the vertical heat treatment apparatus 1 have different surface areas. That is, it may be considered that the wafers are subjected to different treatments for every lot and they are mounted in the wafer boat 3 in a state that line width of patterns or thickness of a film formed with convex and concave portions is different. In this case, for example, plural kinds of quartz wafers 71 in the first embodiment, which are detachably attached to the wafer boat 3 and have different surface areas, are prepared. Among the plural kinds of quartz wafers 71, quartz wafers 71 to be mounted in the wafer boat 3 may be selected according to the lot of wafers 10 on which the film forming treatment is performed in the vertical heat treatment apparatus 1. Accordingly, the amount of a gas supplied to the wafers 10 at the upper and lower sections of the wafer boat 3 can be controlled for every lot of wafers 10, thereby further improving uniformity of film thicknesses of the wafers 10 among respective slots.
Evaluation tests performed according to the present disclosure will be described. In Evaluation Test 1, as described in the BACKGROUND, bare wafers 72 were mounted in a plurality of slots at an upper section of the wafer boat 3 and a plurality of slots at a lower section of the wafer boat 3, wafers 10 were mounted in other slots, and a film forming treatment was performed in the vertical heat treatment apparatus. After the film forming treatment, the film thickness of the wafer 10 in each slot was measured. Further, in Evaluation Test 2, test wafers were mounted instead of the bare wafers 72 and a film forming treatment was performed. The test wafer has the same surface area as the wafer 10 and is made of the same material as the wafer 10. The surface area of both the wafer 10 and the test wafer is three times greater than that of the bare wafer 72.
Although an apparatus configured to be approximately similar to the apparatus of the aforementioned embodiment was used as the vertical heat treatment apparatus used in this evaluation test, an injector for supplying DCS gas is configured as shown in
The graph of
According to the present disclosure, gas distribution adjusting members made of quartz are provided to be positioned respectively above and below a region in which a plurality of target substrates, which are held and supported by a substrate holding and supporting unit, are disposed. Thus, gas supply amounts into above and below the substrate holding and supporting unit can be adjusted respectively, thereby improving uniformity of film thicknesses among the substrates. Further, since the gas distribution adjusting members are made of quartz, the gas distribution adjusting members are difficult to be etched by a cleaning gas, which is a fluorine-based gas including fluorine or a fluorine compound supplied into the reaction tube, as compared with the gas distribution adjusting members made of silicon. Thus, the gas distribution adjusting members can be cleaned together with the interior of the reaction tube by the gas, thereby saving labor for operating an apparatus.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosures. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the disclosures. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosures.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-047790 | Mar 2014 | JP | national |
