JPH0277117A - Heat-treating equipment - Google Patents

Abstract

PURPOSE:To miniaturize a reactor reduce the cost and improve uniformity of the treatment as the result of the equipment miniaturization by arranging the rotary axis of a group of objects to be treated, in an offset relation with respect to the center axis of the reaction vessel. CONSTITUTION:On the outer side of a treating vessel 11, a cylindrical heater 22 is arranged so as to surround the treating vessel 11. In the treating vessel 11, a wafer boat 14, which mounts a plurality of semiconductor wafers 13 as objects to be treated at specific pitches, is installed on a boat-elevator 15 in the manner in which the wafers 13 are kept horizontal. The center axis of the wafers 13 is set at a position displaced from the center axis of the treating vessel 11. Gas jetting vents 17 are arranged so as to correspond with the arrangement pitch of the wafers 13 mounted on the boat 14. Reactive gas jetted from each jetting vent 17 is effectively supplied to each of the wafers 13. The boat elevator 15 is rotated by a rotary mechanism 22, around the center axis as the rotary axis. Since the boat 14 is arranged in the off-set manner, the volume of the treating vessel 11 can be reduced.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a heat treatment apparatus.

(Prior Art) In recent years, vertical heat treatment apparatuses have been developed as heat treatment apparatuses used in thermal diffusion processes and film formation processes in semiconductor device manufacturing processes.

A vertical heat treatment apparatus has a cylindrical processing container arranged with its longitudinal direction vertical, and a boat containing a processing object, such as a semiconductor wafer, is inserted into the container to heat-process the wafer.

This vertical heat treatment is becoming widely used because it can save space and energy, and it can easily handle larger diameter wafers as objects to be processed and automation of processing.

Conventionally, a typical vertical heat treatment apparatus is a hot wall type apparatus in which a heater is arranged around a reaction vessel.

When performing heat treatment using such heat treatment equipment,
Load multiple wafers at a predetermined pitch on a wafer boat,
The boat is set in the center of the processing container so that the center axis of the loaded wafers matches the center axis of the processing container.

Then, a gas depending on the processing content (for example, SiH□C for Si epitaxial growth) is supplied into the processing container, and a rotation mechanism is used to rotate around the central axis of the wafer in order to make the heat treatment uniform. Heat treatment is performed at a predetermined temperature (for example, 1000 to 1100° C.) while rotating the wafer boat. At this time, the spent gas is discharged from an exhaust port provided in the reaction vessel.

(Problems to be Solved by the Invention) By the way, in such a vertical heat treatment apparatus, there are the following objectives: 1) improvement of thermal efficiency, 1) saving of reaction gas, 1) facilitation of gas exhaust inside the reaction vessel,
In order to reduce equipment costs, the capacity of the processing container has been reduced to t's.
It is hoped that this will be reduced.

However, in conventional vertical heat processing equipment, a pipe may be inserted into the processing container to discharge reaction gas toward the wafer, and the wafer boat is placed in the center of the processing container. However, there is a certain limit to reducing the capacity of the processing container, and the current situation is that a sufficient one has not yet been obtained.This invention was made to eliminate these drawbacks of the conventional technology. The objective is to provide a heat treatment apparatus in which the size of the reaction vessel can be reduced to a sufficient extent to improve thermal efficiency, save reaction gas, facilitate gas exhaust, and reduce apparatus cost.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a heat treatment apparatus having one reaction vessel and a rotation mechanism for rotating a group of objects to be treated provided in the reaction vessel, in which a rotation axis of the group of objects to be treated is rotated. The present invention provides a heat treatment apparatus characterized in that the heat treatment apparatus is arranged offset with respect to the central axis of the reaction vessel.

(Function) The present invention makes it possible to downsize the reaction vessel by arranging the rotational axis of a group of objects to be processed in a heat treatment apparatus offset from the central axis of the reaction vessel, thereby improving thermal efficiency and saving reaction gas. , it is possible to improve gas exhaust efficiency and reduce equipment costs.

(Example) Hereinafter, an example of the apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing a vertical heat treatment apparatus according to an embodiment of the present invention. The reaction vessel, for example, the processing vessel 11, has a cylindrical shape with a dome-like upper end, and is made of a heat-resistant material, such as quartz glass.

A cylindrical heater 12 serving as a heating means is provided outside the processing container 11 so as to surround the processing container 11 .

Inside the processing container 11 is a wafer boat 1 on which a plurality of semiconductor wafers 13 as objects to be processed are arranged and mounted at a predetermined pitch.
4 is placed on a boat plate 15 with the wafer 13 held horizontally. The plurality of wafers 13 mounted on the wafer boat 14 have their central axes offset from the central axis of the processing container 11, as will be described later.

An exhaust pipe 20 is connected to the lower part of the peripheral wall of the processing container 11, and the gas inside the processing container 11 is exhausted from the exhaust pipe 20 by an exhaust pump (not shown), so that the inside can be maintained under reduced pressure. .

Further, on the side of the wafer boat 14, a reaction gas discharge pipe 16 is provided which extends vertically from near the bottom of the processing container 11 and has a plurality of gas discharge ports 17 formed toward the wafers 13. . A gas supply pipe 2I extending from a reactive gas source 18 is connected to this gas discharge pipe 16, and a gas flow rate control valve 19 is provided on this gas supply pipe 2I. Then, a desired reaction gas is supplied from one reaction gas source 18 into the processing container 11 from the gas discharge port 17 through the gas supply pipe 21 and the gas discharge pipe 16 while adjusting the flow rate by the flow rate control valve 19 .

Each gas discharge port 17 is connected to a wafer 13 mounted on a boat 14.
The reactive gas discharged from each discharge port I7 is thereby effectively supplied to each wafer 13.

The boat elevator 15 described above is raised and lowered by a drive device (not shown), and is rotated about its central axis by a rotation mechanism 22 including a motor and a speed reducer.

As the elevator 15 rotates, the wafer boat 14 placed thereon is rotated about the central axis of the wafers 13.

In this case, the boat elevator 15 is
As shown in the figure, from the center axis load of the processing container 11 to the side opposite to the gas discharge pipe 16, there is a deviation of ms [
It is arranged so that its axis of rotation is located at b. By arranging the boat 14 offset in this way,
The capacity of the processing container 11 can be reduced.

Note that this deviation fis- may be of a length such that the boat does not come into contact with the inner wall of the processing container 11;
It is preferable that the distance from the inner wall of wafer 1 to the outer periphery of wafer 13 as an object to be processed is set to be -F3a+m or more at the shortest point. Moreover, it is preferable that the deviation ms is 2 to 10% of the inner diameter of the processing container 11.

A specific example of such a vertical heat treatment apparatus is 1, for example, 6
When processing inch-sized semiconductor wafers, processing container 1
The inner diameter r of heater 1 is 216 m, and the inner diameter R of heater 12 is 268 m.
rrtn, 7.5 mm above the deviation amount, wafer rotation axis Σ
The farthest length from the to the inner wall of the processing container 11 is iis, sm
When the farthest length from the wafer rotation axis to the inner periphery of the heater 12 is set to 141.5 m+, the inner diameters of the processing chamber 11 and the heater 12 can be reduced by about 151 m1 compared to the conventional one.

It was previously thought that if the rotation axis of the semiconductor wafer and the center axis of the processing container were misaligned, heating and reaction gas supply would be uneven, making uniform processing difficult. However, since the heat treatment is performed during the process, such problems do not occur.

Next, an outline of the processing operation of such a vertical heat treatment apparatus will be explained.

First, the boat elevator 15 is lowered from the processing container 11, and the wafer boat 14 on which the wafers 13 are mounted at a predetermined pitch is placed on the elevator 15, and then the elevator 15 is raised to move the boat 14 to the processing container II. Install it at the specified location inside. Thereafter, the processing container 11 is sealed by a sealing mechanism (not shown), and the inside thereof is evacuated to maintain a predetermined reduced pressure state.

In this state, while rotating the wafer 13 by the rotation mechanism 22, the reaction gas source 18 flows through the gas supply pipe 21 and the gas discharge pipe 16 to supply a desired reaction gas from the discharge port 17 into the processing container 11. . At this time, the flow rate of the reaction gas is supplied by the gas flow rate control valve 19. The rotation speed of the wafer 13 varies depending on the diameter of the wafer and the processing content, but for example, the rotation speed of the wafer 13 is 1000 to 1100°C for a 6-inch wafer.
When epitaxially growing Si using 5 IT (□CQ□), a uniform film can be formed by rotating at about 10 rpm.

Then, by applying current to the heater 12, the wafer 13 in the processing container 11 is heat-treated.

As explained above, since the center axis of the wafers 13 set on the wafer boat 14 is offset from the center axis of the processing container 11, the processing container 11 can be downsized. Additionally, the heater 12 and other peripheral devices can also be downsized, and the cost of the device can be reduced. Furthermore, by reducing the capacity of the processing container 11, the uniformity of one reaction gas and the exhaust efficiency can be improved, and thereby the uniformity of the processing can be improved.

Note that this invention is not limited to the above embodiments and can be modified in various ways. For example, in the above embodiment, the wafer S
Although the i-epitaxial growth process has been described, the present invention is not limited to this, and can be applied to other processes such as CVD and thermal diffusion. Further, although the description has been given using a semiconductor wafer as an example of the object to be processed, the present invention is not limited to this and can be applied to other objects such as an LCD substrate.

Further, although a gas discharge pipe is used to supply the reaction gas, it is also possible to simply provide a gas inlet in the processing container.

〔Effect of the invention〕

As explained above, according to the heat treatment apparatus of the present invention, it is possible to reduce the size of one reaction vessel, thereby reducing the cost and improving the uniformity of the treatment by reducing the size of the apparatus.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a vertical heat treatment apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining the boat arrangement position in the reaction vessel of the heat treatment apparatus shown in FIG. 1. . 1... Reaction container 13... Wafer 14...
Boat 16... Gas discharge pipe 22... Rotating mechanism

Claims (1)

[Claims] In a heat treatment apparatus having a reaction container and a rotation mechanism for rotating a group of objects to be processed provided in the reaction container, a rotation axis of the group of objects to be processed is arranged offset with respect to a central axis of the reaction container. A heat treatment device featuring: