JP2736127B2 - Object boat and vertical heat treatment apparatus using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a boat for an object to be processed and a vertical heat treatment apparatus using the same.

(Prior Art) In general, a method of loading a substrate to be processed into a furnace in a vertical film forming apparatus includes, as shown in FIG.
A plurality of wafers 14 are placed in a horizontal state on a boat 18 for accommodating a wafer 20 as a substrate to be processed, inside a double-tube type vertical heat treatment furnace comprising an outer tube 10 and an inner tube 12. At a predetermined interval while supporting the arrangement. The boat 18 placed in the furnace is a film forming film capable of obtaining sufficient film thickness uniformity with respect to the material gas in each furnace temperature distribution shown in FIG. Then, the film is set in the region and the film forming process is executed.

Here, the lower ends of the tubes 10 and 12 are connected to the manifold 22.
The manifold 22 is supported and connected to a gas inlet pipe 24a for process gas, a gas inlet pipe 24b for purge gas, and an exhaust pipe 26, respectively.

Further, a boat elevator 30 for carrying the boat 18 in and out of the inner tube 12 is provided. The elevator arm 32 of the boat elevator 30 has a lid 34 for sealing the lower end opening of the manifold 22 and reducing the pressure inside the furnace, and a transfer jig receiving base 36 fixed above the lid 34. have. And the cradle 36
A heat insulating cylinder 38 also serving as a transport jig is placed on the upper part, and the boat 18 is detachably supported on the upper end of the transport jig and heat insulating cylinder 38. Here, the transfer jig and heat retaining cylinder 38 is formed to have a predetermined length, thereby raising the bottom of the boat 18 in the inner tube 12, and moving the boat 18 to the furnace temperature distribution in the inner tube 12. It has the function of assisting the optimal heat uniformity and the uniformity of film thickness at the bottom of the boat 18 for the film forming temperature region, and also prevents heat convection, radiation, etc. to maintain the heat equalizing zone, It also serves as a heat insulator.

(Problem to be Solved by the Invention) FIG. 4 shows a vertical furnace temperature distribution in the vertical film forming apparatus described above. The solid line in the figure is an example of the temperature distribution in the furnace in the vertical direction at the time of forming the polysilicon film.
The furnace temperature in the film formation temperature range is about 630 ° C. On the other hand, the dashed line in the figure shows an example of the temperature distribution in the furnace longitudinal direction during the formation of the silicon nitride film, and the temperature in the film formation temperature region is about 780 ° C. Here, in a state where the temperature is set to a predetermined condition temperature in the film forming temperature range, the inner tube 1 is connected through the gas introduction pipe 24a.
When a desired process gas is introduced into 2, the reaction of the process gas is promoted, and a polysilicon film or a silicon nitride film as a reaction product is deposited on the surface of the wafer 20, thereby realizing a film forming process. .

Incidentally, the above-described film forming operation is performed not only on the surface of the wafer 20 but also on another member disposed in the temperature region, for example, the boat 18 or the like.
Here, the lower end of the boat 18 and the upper end of the transfer jig / heat insulating cylinder 38 are connected and supported.
The upper end support position A of 38 is located near the lower end of the film forming temperature region, and the upper end support position temperature A 'is maintained at substantially the same temperature as the temperature in the upper temperature region. Therefore, the above-described film forming process is also performed near the upper end support position A of the heat retaining cylinder 38.

Here, there are two methods described below for transferring the wafers 20 between the boat 18 and a carrier (not shown) in which the wafers 20 are stored. One is that after unloading the boat 18 from the inner tube 12, the boat 18 is removed from the upper end of the transfer jig and heat retaining cylinder 38, and the boat 18 is transferred by itself and set to the wafer transfer position. The transfer of wafers between the carrier and the boat 18 is performed. The other is to transfer wafers to and from the carrier while unloading the boat 18 from the inner tube 12 and then supporting the boat 18 at the upper end of the transfer jig and heat retaining cylinder 38. is there.

In the former method, it is indispensable to remove the boat 18 from the transfer jig / heat insulating cylinder 38 every time one cycle of the film forming operation is completed. On the other hand, regardless of whether the former or the latter method is adopted, it is necessary to periodically clean the boat 18, so in this case, it is necessary to remove the boat 18 from the transport jig and heat retaining cylinder 38. Become indispensable.

However, when the boat 18 is detached from the upper end of the transfer jig / warming cylinder 38, since the film formation is also performed at the support position A, the boat 18 and the transfer jig / warming cylinder 38 are connected to each other. The film forming operation causes adhesion, which hinders the separation operation. Further, when the two are separated, the film always peels, so that a clean atmosphere around the semiconductor manufacturing apparatus is contaminated, and the peeled film adheres to the wafer 20 as particles, which has an adverse effect. .

An object of the present invention is to set a support position where a boat is supported by a member on which the boat is mounted, outside a reaction temperature range, and furthermore, a conventional heat retaining cylinder is provided in a region immediately below a storage portion for storing an object to be processed. An object of the present invention is to provide a boat for an object to be processed which can have the same function as the above, and a vertical heat treatment apparatus using the same.

[Constitution of the Invention] (Means and Actions for Solving the Problems) The present invention extends the lower side of a housing section for housing an object to be processed, and uses this extended section as a heat insulating section having a heat insulating effect or a heat insulating effect. The heat insulating part has

Due to the presence of the heat retaining portion or the heat insulating portion, the position where the boat is supported by the support member that stands and supports the boat can be set at a position further below the heat equalizing region as compared with the related art. Can be set outside the reaction area.

Further, since the lower extension of the housing portion is configured as a heat insulating portion or a heat insulating portion, the same heat insulating effect and heat insulating effect as those of the heat insulating cylinder conventionally arranged in the region can be exerted, and the uniformity can be achieved. The heat zone is not adversely affected.

(Embodiment) An embodiment in which the present invention is applied to a film forming apparatus for a semiconductor wafer will be specifically described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of a vertical film forming apparatus according to an embodiment. Of the members shown in FIG. 1, members having the same functions as those shown in FIG. A detailed description thereof will be omitted.

The difference between the present embodiment and the conventional apparatus shown in FIG. 3 is as follows.

Boat 40 for storing substrates to be processed used in the present embodiment
Is extended at its lower end, while the transfer jig and heat insulation cylinder 60
Has a shorter overall length, so that the lower end support position A of the boat 40 is set lower than the conventional position.

FIGS. 2A to 2C show such a boat 40.
The following can be adopted.

As a common configuration of the boat 40 shown in FIG.
A wafer storage portion 42 having locking grooves (not shown) formed at predetermined intervals in the vertical direction on the vertical rod 42a, an extension portion 44 integrally formed below the wafer storage portion 42, and the extension portion An insertion portion 46 is formed below the bottom 44 and is inserted into a groove (not shown) of the transport jig / heat insulating cylinder 60.

The boat 40 shown in FIG. 4A has a plurality of fins 50 having a heat retaining effect as a configuration of the extension portion 44. The lower surface of the lowermost fin 50 functions as a stopper when the boat 40 is inserted into the transfer jig / heat insulating cylinder 60.

The boat 40 shown in FIG. 6B is formed by a cylindrical portion 52 having a heat retaining effect also on the extension portion 44,
A flange 52a having a larger diameter than the insertion portion 46 is provided between the cylindrical portion 52 and the insertion portion 46, and the flange 52a functions as the stopper.

In the boat 40 shown in FIG. 3C, the extension 44 is formed by a vacuum insulation chamber 54. The vacuum insulation chamber 54 is formed as a hollow cylindrical portion having a diameter larger than that of the insertion portion 46, and the inside thereof is evacuated. Also, preferably, the hollow portion may be filled with a heat insulating material such as quartz wool.

The material of the boat 40 has heat resistance,
In addition, a material with little impurity precipitation, such as quartz glass,
Polysilicon, SiC or the like can be used.

 Next, the operation will be described.

FIG. 4 shows the temperature distribution in the vertical direction in the vertical film forming apparatus shown in FIGS. 1 and 3. The solid line in FIG. The respective temperature distributions for forming the silicon nitride film are shown.
In both cases, the film forming temperature region is the soaking zone, the peel film forming temperature region below and the unreacted temperature region below.

Here, the lower end of the boat 40 is a transfer jig and heat insulating cylinder 60.
In the case of the polysilicon film forming process, the temperature A ′ corresponding to the upper end support position A supported by the upper end support position A is 47 °.
It is 0 ° C. The present inventors have proposed an injection type process gas gas introduction pipe 24 as shown in FIG.
When a was disposed, it was confirmed that at a temperature of 470 ° C. corresponding to the upper end support position A, the decomposition reaction of SiH _{4 as} the process gas was not started, and therefore, a film forming operation was not performed in this temperature range. did. Similarly, at the time of the silicon nitride film forming process, the temperature corresponding to the upper end support position A is 600 ° C., but it can be confirmed that even under this temperature, the film forming operation of the silicon nitride film using the material gas is not started. Was.

As described above, according to the present embodiment, the decomposition reaction step for film formation is not performed in the upper end support position A of the boat 40, that is, in the atmosphere at the portion where the boat 40 is attached to and detached from the transfer jig and heat retaining cylinder 60. The work of removing the boat 40 from the transfer jig / heat insulating cylinder 60 can be performed smoothly without any trouble, and no defective factor such as particles is generated at the time of the removal. Therefore, when the boat 40 is transferred and the wafers are transferred after the boat 40 is unloaded from the inner tube 12, the transfer jig and the heat insulating cylinder are required each time.
Although the boat 40 is removed from the boat 60, the removal operation can be performed smoothly each time, and the occurrence of defective factors such as particles can be suppressed. Furthermore, after unloading the boat 40 from the inner tube 12, in any method including wafer transfer in a state where the boat 40 is mounted on the transfer jig and heat retaining cylinder 60, the boat 40 is periodically The cleaning and cleaning are necessary, but the above operation and effect can be obtained even when the boat 40 is removed during the cleaning.

Here, any one of the boats 40 shown in FIGS. 2A to 2C is used as the boat used in the above-described embodiment, and the extension 44 of each boat 40 is the same as that of the conventional heat insulation cylinder in the furnace vertical direction. (A) in which the heat insulation effect can be effectively performed in this area because
Alternatively, it is preferable to employ a boat 40 shown in FIG. In the case of the boat 40 shown in FIG. 2A, heat radiation can be prevented by the fins 50, and convection of heat can also be suppressed. On the other hand, in the case of the boat 40 shown in FIG. 4C, since the inside of the vacuum heat insulating chamber 54 is evacuated, the heat convection inside this is suppressed, and effective heat insulation can be performed. Further, by arranging a heat insulating material such as quartz wool in the evacuated space, the heat insulating effect can be further enhanced.

It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention.

The desired temperature in the film formation temperature range varies depending on the type of process, and in the case of a high-temperature process, there is a temperature exceeding 1000 ° C. Film can be prevented. At this time, a boat for high temperature process of 1000 ° C or more,
It can also be used as a boat for low-temperature processes at around 600 ° C. That is, a boat that can set the upper end support position A in a region lower than the lowest temperature among the decomposition reaction start temperatures in each film forming process may be used.

[Effects of the Invention] According to the present invention, the position at which the boat is supported by the support member during the processing of the processing target can be set outside the reaction region, and the temperature is kept below the storage section that stores the processing target. Further, since the heat treatment is performed, there is no adverse effect on the soaking area where the object is processed.

[Brief description of the drawings]

FIG. 1 illustrates one embodiment of the present invention, and is a cross-sectional view of a vertical film forming apparatus, FIG. 2 is a schematic perspective view of a boat used in the embodiment, and FIG. FIG. 4 is a schematic cross-sectional view for explaining a vertical film forming apparatus, and FIG. 4 is a temperature distribution characteristic diagram in a vertical direction in a furnace of the vertical film forming apparatus. 10 ... outer tube, 12 ... inner tube 14 ... heater 20 ... substrate to be processed (wafer) 22 ... manifold 24 a ... process gas gas inlet pipe 24 b ... purge gas inlet pipe 26 ... exhaust pipe, 28 …… O-ring 30 …… Boat elevator 32 …… Elevator arm 34 …… Lid, 36… Transport jig cradle 38,60… Transport jig and heat insulation tube (heat insulation tube) 18, 40: Processing substrate storage jig (boat) 42a: Vertical rod, 42: Processing substrate storage section 44: Extension, 46: Insertion section 50: Fin 52a: Flange, 52: Cylindrical Part 54: Vacuum insulated chamber A: Upper-end support position A ': Upper-end support position temperature

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-47020 (JP, A) JP-A-54-78969 (JP, A) JP-A-63-283019 (JP, A) 218117 (JP, U) Fully open 63-20426 (JP, U) Fully open 63-195721 (JP, U)

Claims (12)

(57) [Claims] 1. A boat for an object to be loaded and unloaded into and out of the vertical heat treatment furnace, supported by a transfer jig which is driven up and down with respect to the vertical heat treatment furnace. A plurality of objects to be processed are accommodated, and a housing part arranged in the reaction region of the heat treatment furnace, and a heat insulation part provided below the accommodation part and having a heat insulation effect, A boat for an object to be processed, wherein a lower end of the heat retaining portion is detachably supported by the transfer jig outside the reaction region. 2. The boat for an object to be processed according to claim 1, wherein the heat retaining portion has a shaft portion and a plurality of plates projecting outward from a side wall of the shaft portion. 3. The boat for an object to be processed according to claim 1, wherein the heat retaining portion has a shaft portion and a plurality of fins protruding outward from a side wall of the shaft portion. 4. A boat for a workpiece to be carried into and out of the vertical heat treatment furnace, supported by a transfer jig that is driven up and down with respect to the vertical heat treatment furnace, at predetermined intervals in the vertical direction. And a housing portion that houses a plurality of workpieces and is disposed in the reaction region of the heat treatment furnace; and a heat insulating portion that is provided below the housing portion and that prevents heat radiation below the housing portion. And a lower end of the heat insulating portion is detachably supported by the transfer jig outside the reaction region. 5. A boat for an object to be loaded and unloaded into and out of the vertical heat treatment furnace, which is supported by a transfer jig which is driven up and down with respect to the vertical heat treatment furnace. And a housing section for housing a plurality of objects to be processed and arranged in a reaction region of the heat treatment furnace; and a heat insulating section provided below the housing section for preventing convection of heat. And a lower end of the heat insulating portion is detachably supported by the transfer jig outside the reaction region. 6. A boat for an object to be loaded and unloaded into and out of the vertical heat treatment furnace, which is supported by a transfer jig that is driven up and down with respect to the vertical heat treatment furnace. And a housing portion that houses a plurality of objects to be processed and is disposed in a reaction region of the heat treatment furnace; and a heat insulating portion that is provided below the housing portion and insulates between the housing portion and a region below the housing portion. And a lower end of the heat-insulating portion is detachably supported by the transfer jig outside the reaction region. 7. A processing object boat, in which a plurality of objects to be processed are accommodated in a vertical heat treatment furnace at predetermined intervals in a vertical direction, is transported by a transfer jig. In the vertical heat treatment apparatus configured to process a plurality of the objects to be processed, the object boat may include: an accommodation unit that accommodates the plurality of objects to be disposed arranged in the soaking region; And a heat retaining portion having a heat retaining effect, which is provided below the portion, and integrally comprising: a lower end of the heat retaining portion is detachably supported by the transport jig outside the heat equalizing region. A vertical heat treatment apparatus. 8. The vertical type according to claim 7, wherein the heat retaining portion of the boat for processing object has a shaft portion and a plurality of plates protruding outward from a side wall of the shaft portion. Heat treatment equipment. 9. The vertical heat treatment according to claim 7, wherein the heat retaining portion of the boat for processing has a shaft portion and a plurality of fins protruding outward from a side wall of the shaft portion. apparatus. 10. A processing object boat, in which a plurality of objects to be processed are accommodated in a vertical heat treatment furnace at predetermined intervals in a vertical direction, is transported by a transfer jig. In the vertical heat treatment apparatus configured to process a plurality of the objects to be processed, the object boat may include: an accommodation unit that accommodates the plurality of objects to be disposed arranged in the soaking region; And a heat insulating portion that is provided below the housing portion and that prevents heat radiation below the housing portion. A vertical heat treatment apparatus, which is detachably supported on the apparatus. 11. A processing object boat, in which a plurality of objects to be processed are accommodated in a vertical heat treatment furnace at predetermined intervals in a vertical direction, is transported by a transfer jig. In the vertical heat treatment apparatus configured to process a plurality of the objects to be processed, the object boat may include: an accommodation unit that accommodates the plurality of objects to be disposed arranged in the soaking region; A heat insulating portion for preventing heat convection from being provided, and a lower end of the heat insulating portion is detachably supported by the transfer jig outside the heat equalizing region. A vertical heat treatment apparatus. 12. A boat for processing objects, which accommodates a plurality of objects to be processed at predetermined intervals in a vertical direction, is loaded into a vertical heat treatment furnace by a transfer jig, and a heat equalizing area is provided. In the vertical heat treatment apparatus configured to process a plurality of the objects to be processed, the object boat may include: an accommodation unit that accommodates the plurality of objects to be disposed arranged in the soaking region; And a heat insulating portion that is provided below the portion and that insulates the space between the housing portion and the area below the housing portion. A vertical heat treatment apparatus, which is detachably supported by a tool.