JP2648751B2 - Heat treatment method and heat treatment apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a heat treatment method and a heat treatment apparatus.

(Prior Art) Generally, in a semiconductor manufacturing process, a heat treatment furnace is used to form various thin films such as an insulating film, a compound semiconductor, and an organic metal on a semiconductor wafer. In such a processing furnace, usually 100 or more wafers are processed at a time in order to improve mass productivity. Such processing furnaces include a horizontal furnace in which the furnace is placed in the horizontal direction and a vertical furnace in which the furnace is placed in the vertical direction. Recently, vertical furnaces that can reduce the installation space have attracted attention.

In the vertical furnace, a heat treatment furnace with an opening facing the bottom side is arranged above a vertically erected housing, and a loading mechanism for housing a boat from the opening of the heat treatment furnace is arranged below. ing. The loading mechanism vertically mounts a boat containing semiconductor wafers (hereinafter abbreviated as wafers) on a turntable, further describes the turntable on a susceptor, moves the susceptor up and down, and moves the susceptor up and down. Loading / unloading the boat inside.

Japanese Patent Application Laid-Open No. 58-9222 discloses such a technique.
There are many methods disclosed in, for example, Japanese Patent Application Laid-open No. 0, JP-A-62-298107 and the like. When a boat is accommodated in a processing furnace in the conventional heat treatment method, first, as shown in FIG. 4 (a), eccentric deflection of two types of boats (1) is detected.
One type is eccentric to the boat (1) before being stored in the boat (1) from a wafer cassette (not shown) at a transfer position (3) at a predetermined distance L from the axis of the processing furnace (2). Eccentricity is detected to check if there is any deflection.

In other types, the eccentricity (deflection) of the boat (1) is detected before transfer from the boat (1) to the wafer cassette.

As a method for detecting the eccentricity (deflection) of the boat (1), the boat (1) which is erected as shown in FIG.
Is provided with a quartz disk (4) coaxially with its central axis. The disk (4) has a gap groove (7) so that a detection sensor (5), for example, a light-emitting element (5a) enters the light-receiving element (5b) when the light-emitting beam (6) passes therethrough. The boat (1) is opened in the X-axis direction and the Y-axis direction through the center axis thereof.

A light-emitting element (5a) and a light-receiving element (5b) are arranged corresponding to the outer circumference of the disk (4) on the straight line extending in the X-axis direction and the Y-axis direction.

Then, the deflection of the boat (1) can be detected by passing the light-emitting beam (6) through the gap groove (7).

Further, in order to detect the height position of the boat (1), a wafer storage shelf groove (8) at the top of the boat (1) and a reference surface (8a) having a fixed height are provided. (8a)
Is separately provided.

Even with such a detection method, it is possible to detect deflection.

(Problems to be Solved by the Invention) However, in the conventional heat treatment method, since the disc provided on the boat is vulnerable to thermal deformation, the disc is deformed, and the gap groove is closed, so that efficient detection of eccentricity is achieved. Could not be done.

Moreover, in the conventional heat treatment method, detection sensors must be provided in both the X-axis direction and the Y-axis direction, and adjustment is difficult.

An object of the present invention is to solve the above problems, reduce the influence of thermal deformation, reliably and easily detect deflection without eccentricity of a boat, easily adjust a sensor, and improve processing efficiency. It is an object of the present invention to provide a heat treatment method and a heat treatment apparatus that can achieve the above.

[Configuration of the invention]

(Means for Solving the Problems) According to the present invention, a vertical boat in which a plurality of objects to be processed are arranged and supported is placed on a susceptor of a loading mechanism, loaded into a vertical heat treatment furnace, and the object to be processed is heat-treated. In the method
A step of mounting the boat having a disk provided with an axis aligned at the top on the susceptor at a predetermined standby position, and rotating the boat mounted on the susceptor to make a tangent to the disk Detecting the eccentric deflection of the boat by detecting whether or not the eccentricity detection optical path formed in the direction is blocked by a disc; and heat-treating the boat when the eccentric deflection of the boat is not detected. And a step of carrying into a furnace.

Further, the present invention is an apparatus for placing a vertical boat in which a plurality of workpieces are arranged and supported on a susceptor of a loading mechanism and loading the same into a vertical heat treatment furnace, and heat-treating the workpiece, A disk provided with the axis aligned at the top, a turntable provided on the susceptor, and mounted and rotated by the boat, and an eccentricity detection optical path in the tangential direction of the disk on the boat. A sensor that is arranged to be formed and that detects whether or not the boat is eccentric and has no deflection by detecting whether or not the eccentricity detection optical path is interrupted by a disk on the boat rotated by the turntable; And a controller for driving the loading mechanism so that the boat is carried into the heat treatment furnace when the deflection without eccentricity is not detected.

(Operation) According to the heat treatment method of the present invention, the boat is placed on the susceptor and rotated, and the eccentricity detection optical path formed in the tangential direction of the disk provided on the boat rotates together with the boat. Since the eccentric deflection of the boat is detected based on whether or not it is blocked by the disk, and the eccentric deflection of the boat is not detected when the eccentric deflection of the boat is not detected, the conventional heat treatment method is used. Unlike this, the disk is not deformed due to thermal deformation and cannot be detected, the deflection without eccentricity of the boat can be detected reliably and easily, and the boat without eccentricity can be smoothly processed in the heat treatment furnace. , And the processing efficiency can be improved. Moreover, since the eccentricity detection optical path can be formed by, for example, a pair of light-emitting and light-receiving sensors, the configuration is simplified and the adjustment of the sensor is facilitated.

Further, according to the heat treatment apparatus of the present invention, a boat provided with a disk at the upper part with its axis aligned is placed on a turntable provided on the susceptor and rotated to rotate the boat on the boat. A sensor arranged to form an eccentricity detection optical path in the tangential direction of the plate detects whether the eccentricity detection optical path is interrupted by a disk rotating together with the boat and detects the presence or absence of eccentricity of the boat. When a deflection mechanism without eccentricity of the boat is not detected, the loading mechanism is driven by the controller to carry the boat into the heat treatment furnace.
It is possible to reliably and easily detect the eccentric deflection of the boat without the disk becoming thermally deformed and undetectable, and to smoothly load the eccentric or undulating boat into the heat treatment furnace. And the processing efficiency can be improved. Moreover, since the eccentricity detection optical path can be formed by, for example, a pair of light-emitting and light-receiving sensors, the configuration is simplified, and the adjustment of the sensor is facilitated.

(Example) Hereinafter, an example in which the present invention is applied to a silicon epitaxial growth apparatus will be specifically described with reference to the drawings.

The vertical path has a process tube (11) having a vertical axis in the axial direction as shown in FIG. 1, and the process tube (11) has an outer cylinder (12) as shown in FIG. And the inner cylinder (13), and a number of holes (1
4) is formed. In addition, a process gas introduction pipe (not shown) is inserted and supported from the lower end toward the upper end of the inner cylinder (13), so that a process gas or the like can be introduced into the inner cylinder (13). Has become. The exhaust gas such as the process gas is led to the outer cylinder (12) through the hole (14) formed in the inner cylinder (13), and the gas is connected to the lower end of the outer cylinder (12). The air is exhausted through a pipe (not shown).

Around the process tube (11), for example, an electric resistance heater (15) is arranged as a heating means.
Although not shown, a heat insulating material is arranged around the heater (15) so as to surround the heater.

Into the process tube (11), a quartz boat (16) in which a plurality of semiconductor wafers (not shown) arranged and supported in a horizontal state and vertically separated can be carried in a vertical direction. At the lower end of this boat (16), a heat insulating cylinder (1) for positioning the boat (16)
A loading mechanism (18) is provided for loading and unloading the boat (16) into and from the process tube (11) by vertically moving the heat retaining tube (17). It should be noted that the heat retaining cylinder (17) can be configured to be rotatable, and the uniformity of temperature and gas can be improved.

As shown in FIG. 2, the loading mechanism (18) is driven up and down in the axial direction of the process tube (11). For example, a nut (20) is screwed to a ball screw (19), and the ball screw (19) is connected to the ball screw (19). A susceptor (21) having a central axis coaxial for rotation by a drive motor (not shown) for ascending drive, and a turntable that rotates on the upper surface of the susceptor (21) by θ in a direction perpendicular to the elevating direction. (2
2).

Further, the ball screw (19) is
Is provided upright at the center of rotation of the process tube (11) between the center axis position (23) of the process tube (11) and the transfer position (24) for transferring the boat (16) on the carry-in side.

Here, a characteristic configuration of the present embodiment is that when the boat (16) is thermally deformed, it is detected whether or not the amount of flexing is within an allowable range by the thermal deformation.

That is, as shown in FIG. 2 (b), the boat (16)
Disk 60mm in diameter, outer diameter 100m x thickness
A 30 mm disk (25) is provided.

As shown in FIG. 3 (a), when the boat (16) is placed on the heat retaining tube (17) on the susceptor (21) stopped at the transfer position (24), the boat (16) A detection sensor (26) for detecting whether the boat (16) is eccentric and the boat (16) is bent is provided.

That is, on the tangential extension of the disk (25), a luminous beam (27) as an eccentricity detection optical path formed in the tangential direction is provided.
Boat (16) which is rotated by a turntable (22)
The detection sensor (26) for detecting the presence or absence of eccentric deflection of the boat (16), for example, a light emitting element (26a) and a light receiving element (26b) depending on whether or not the boat is interrupted by the upper disk (25). The light-emitting and light-receiving sensors (26) are provided symmetrically.

Therefore, when the boat (16) is rotated by the drive of the turntable (22), the disk (25) provided on the upper surface of the boat (16) causes the boat (16) to be free from eccentricity outside the allowable range. If it has, it rotates greatly eccentric, and if it is normal or within the allowable range, it cuts off the luminous beam (27) passing tangentially outside the disk (25). Can be detected. Here, if the light emitting beam (27) is cut off, the eccentricity or the amount of deflection of the boat (16) is out of the allowable range, so that the boat needs to be replaced. The loading operation of the boat (16) into the process tube (11) by the loading mechanism (18) is stopped, and a signal for notifying the operator is issued.

Next, the operation in which the boat is accommodated in the vertical reactor will be described.

First, the boat (16) is mounted on the heat retaining cylinder (17) on the susceptor (21) having arrived at the transfer position (24) with a handling arm (not shown).

When the handling arm transfers the boat (16) to the loading mechanism (18), the handling arm automatically returns to the home position of the handling arm.

The boat (16) mounted on the heat retaining cylinder on the side of the loading mechanism (16) makes one rotation by driving the turntable (22) according to a command from the controller.

Due to this rotation, the light-emitting and light-receiving sensor (26)
6) Detects whether eccentric rotation occurs.

For example, as shown in FIG. 2, when a deflection amount δ occurs from the central axis (17a) of the susceptor (21) and the heat retaining cylinder (17), the disk (25) on the boat (16) is caused by the deflection amount δ. Due to the eccentric rotation, the eccentric rotating disk (25) blocks the light-emitting beam (27).

By this interruption, a predetermined program of the controller through the signal circuit of the light emitting and receiving sensor (26)
Stop the loading mechanism (18). In addition, when the emission beam (27) is not interrupted, the deflection amount of the boat (16) without eccentricity is within an allowable range. Therefore, the loading mechanism (18) is automatically driven by a predetermined program of the controller, Boat (17) with process tube (1
1) and the opening of the process tube (11) is closed with the upper surface of the susceptor (21).

(Effects of the Invention) In summary, according to the present invention, the following effects can be obtained.

(1) According to the heat treatment method of the present invention, the boat is placed on the susceptor and rotated, and the eccentricity detection optical path formed in the tangential direction of the disk provided on the boat rotates together with the boat. Since the eccentric deflection of the boat is detected based on whether or not it is blocked by the disk, and the eccentric deflection of the boat is not detected when the eccentric deflection of the boat is not detected, the conventional heat treatment method is used. Unlike
It is possible to reliably and easily detect the eccentric deflection of the boat without the disk becoming thermally deformed and becoming undetectable, and smoothly carry the eccentric, non-deflecting boat into the heat treatment furnace. And the processing efficiency can be improved. Moreover, since the eccentricity detection optical path can be formed by, for example, a pair of light-emitting and light-receiving sensors, the configuration is simplified, and the adjustment of the sensor is facilitated.

(2) According to the heat treatment apparatus of the present invention, a boat provided with a disk at the upper part with its axis aligned is placed on a turntable provided on the susceptor and rotated to rotate the boat. A sensor arranged to form an eccentricity detection optical path in the tangential direction of the disk detects whether the eccentricity detection optical path is interrupted by the disk rotating together with the boat and detects the presence or absence of eccentricity of the boat. When the deflection of the boat is not detected, the loading mechanism is driven by the controller to carry the boat into the heat treatment furnace. Therefore, unlike the conventional heat treatment apparatus, the disk is thermally deformed and cannot be detected. The deflection without eccentricity of the boat can be reliably and easily detected without causing the eccentricity of the boat, and the boat without eccentricity and without deflection is smoothly carried into the heat treatment furnace. It can, thereby improving the processing efficiency. Moreover, since the eccentricity detection optical path can be formed by, for example, a pair of light-emitting and light-receiving sensors, the configuration is simplified, and the adjustment of the sensor is facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of the entire structure for explaining an embodiment in which the present invention is applied to a silicon epitaxial growth apparatus. FIGS. 2 and 3 are diagrams for explaining the detection of deflection of a boat used in FIG. FIG. 4 is a structural explanatory view of a boat and a sensor, and FIG. 4 is a structural explanatory view of a boat and a sensor for explaining conventional deflection detection. 7 ... gap groove, 11 ... process tube 15 ... heater, 16 ... boat 17 ... heat insulating cylinder, 18 ... loading mechanism 21 ... susceptor, 22 ... turntable 23 ... center axis position, 24 ... … Transfer position 25… Disc, 26… Light-emitting / light-receiving sensor 27… Light-emitting beam

Claims (2)

(57) [Claims] 1. A method for heat-treating an object to be processed, wherein a vertical boat in which a plurality of objects to be processed are arranged and supported is placed on a susceptor of a loading mechanism, loaded into a vertical heat treatment furnace, and heat-treated.
A step of mounting the boat having a disk provided with an axis aligned at the top on the susceptor at a predetermined standby position, and rotating the boat mounted on the susceptor to make a tangent to the disk Detecting the eccentric deflection of the boat by detecting whether or not the eccentricity detection optical path formed in the direction is blocked by a disk; and heat treating the boat when the eccentric deflection of the boat is not detected. Carrying out the process into a furnace. 2. An apparatus for heat-treating an object to be processed, wherein a vertical boat in which a plurality of objects to be processed are arranged and supported is placed on a susceptor of a loading mechanism, loaded into a vertical heat treatment furnace, and heat-treated.
A disk provided on the upper part of the boat so that the axes thereof coincide with each other; a turntable provided on the susceptor, on which the boat is mounted and rotated; and an eccentricity in a tangential direction of the disk on the boat. A sensor arranged to form a detection optical path, and a sensor for detecting the presence or absence of eccentric deflection of the boat by detecting whether or not the eccentricity detection optical path is blocked by a disk on the boat rotated by the turntable. And a controller for driving the loading mechanism so as to carry the boat into the heat treatment furnace when no eccentric deflection of the boat is detected.