JP2002184780A - Vertical heat treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To overcome a problem in a conventional vertical heat treatment apparatus that, when a boat is raised and comes near to an opening of a reactor core pipe, the flow rate of an inert gas blown out of the opening becomes fairly high, a dust surrounding the reactor core pipe rises, and thus a semiconductor wafer, a jig, etc., placed around the reactor core pipe may be contaminated. SOLUTION: This vertical heat treatment apparatus 101 includes a boat 3 on which a plurality of semiconductor wafers 2 are horizontally mounted, a vertical reactor core pipe 4 (hereinafter, referred to a reactor core pipe), a heater 5 disposed outside of the reactor core pipe 4 to heat the reactor core pipe 4, a gas supply port 6 for supplying a gas into the reactor core pipe 4, a gas exhausting port 7 for exhausting the gas from the reactor core pipe 4, a position detecting unit 102 for detecting the position of a hatch 8 for an opening 9 and a gas amount regulating unit 103 for regulating the amount of an inert gas to be supplied in order to keep a predetermined flow rate of the inert gas blown out of the opening based on the detected data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vertical heat treatment apparatus for heat treating a semiconductor wafer.

[0002]

2. Description of the Related Art A schematic sectional view showing an example of a conventional vertical heat treatment apparatus will be described with reference to FIG. The vertical heat treatment apparatus 1 includes a boat 3 on which a plurality of semiconductor wafers 2 are mounted horizontally, a vertical furnace tube 4 (hereinafter, referred to as a furnace tube), and a heater disposed outside the boat 3 for heating the furnace tube 4. 5, a gas supply port 6 for supplying an inert gas into the core tube 4,
And a gas exhaust port 7 for exhausting the gas inside.
A hatch portion 8 is provided at the lower portion of the boat 3. When the boat 3 rises from below, the hatch portion 8 causes the opening 9 of the core tube 4 to open.
Is closed.

Next, the operation of the vertical heat treatment apparatus 1 will be described. A plurality of semiconductor wafers 2 are mounted on the boat 3 at a position below the furnace tube 4. When the installation work is completed, the boat 3
Gradually rises into the furnace tube 4 from the lower position. At this time, the air in the furnace core tube 4 is replaced with an inert gas such as nitrogen (indicated by an arrow in the figure) in order to prevent air from being entrained in the reaction system. In the replacement method, a large amount of inert gas is supplied vigorously from a gas supply port 6 provided in the reactor core tube 4 to expel air in the reactor core tube 4 and fill the reactor core tube 4 with the inert gas. Boat 3 rises and hatch 8
The supply of the inert gas is continued until the opening of the furnace tube 4 is closed, and is stopped when the closing is completed.

[0004]

In the conventional vertical heat treatment apparatus, since the air in the furnace tube is replaced with an inert gas, a large amount of water is used until the boat rises and the hatch completely closes the opening of the furnace tube. Supply inert gas. For this reason, when the hatch portion approaches the opening of the furnace tube and the opening area becomes smaller, the flow velocity of the inert gas blown out from the opening becomes considerably high, so that dust around the furnace tube is blown up. This dust has a risk of contaminating semiconductor wafers, jigs and the like in the vicinity of the furnace tube, so that an immediate improvement is required.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent dust around the furnace tube from being blown up due to an increase in the flow rate of an inert gas blown from an opening when the boat is raised.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the above-mentioned problems. A plurality of semiconductor wafers are mounted on a boat, and the semiconductor wafer is placed on a vertical furnace tube having heating means disposed outside. In a vertical heat treatment apparatus, the air in the vertical furnace tube is replaced with an inert gas, and the opening of the vertical furnace tube is closed by a hatch at the bottom of the boat to heat-treat the semiconductor wafer. A vertical heat treatment apparatus comprising a control mechanism for controlling a supply amount of an inert gas in accordance with the ascending operation.

[0007]

FIG. 1 is a schematic sectional view showing an example of a vertical heat treatment apparatus according to the present invention. The same parts as those in FIG. The vertical heat treatment apparatus 101 includes a boat 3 on which a plurality of semiconductor wafers 2 are horizontally mounted, a vertical furnace tube 4 (hereinafter, referred to as a furnace tube), and a heater disposed outside the boat 3 for heating the furnace tube 4. 5, a gas supply port 6 for supplying gas into the core tube 4,
A gas exhaust port 7 for exhausting gas in the reactor core tube 4 and an opening 9
Detection unit 102 for detecting the position of hatch 8 with respect to
And a gas amount adjusting unit 103 for controlling the supply amount of the inert gas to make the inert gas blown from the opening 9 into a predetermined flow rate based on the detection data. The position detecting unit 102 may be any sensor that can recognize the distance between the hatch 8 and the opening 9 such as a recognition camera or a proximity sensor. The supply amount adjustment mechanism of the gas amount adjustment unit 103 may be, for example, a general valve-type adjustment valve.

Next, the operation of the vertical heat treatment apparatus 101 will be described. The plurality of semiconductor wafers 2 are located below the furnace tube 4.
Is mounted on the boat 3. When the mounting operation is completed, the boat 3 slowly rises into the core tube 4 from the lower position. During this ascent operation, the position of the hatch portion with respect to the opening is detected by the position detection unit 102, and based on the data, the inert gas supply amount for adjusting the inert gas blown from the opening 9 to a predetermined flow rate is calculated. The amount of inert gas supplied from the gas supply port 6 is controlled by the gas amount controller 103. FIG.
FIG. 4 is an explanatory diagram showing a relationship between the supply amount of the inert gas and the position of the boat 3 as an example of a suitable control pattern. When the boat 3 starts to enter the furnace and reaches a predetermined ascending position (point a in the figure),
The supply amount of the inert gas, which was constant until then, is reduced, and the opening 9 is closed by the hatch portion 8 to stop the furnace at the same time when the furnace is completed.

In the above description, the position of the hatch 8 with respect to the opening 9 of the furnace tube 4 is detected by the position detector 102. However, the rising pattern of the boat 3 after the start of the lifting operation is stable and the control is performed. If the inert gas supply amount to be calculated can be theoretically calculated, the gas amount adjustment unit 103 may be programmed to perform a gas supply amount adjustment operation in a predetermined pattern in conjunction with the rise of the boat 3. .

In the above embodiment, the position of the hatch portion 8 with respect to the opening 9 is detected, and the inert gas supply amount is adjusted based on the data. However, as shown in FIG.
A configuration in which a flow rate detecting section 202 for detecting the flow rate of the inert gas blown out from the opening 9 is provided near the opening 9 instead of the position detecting section 102, and the inert gas supply amount is adjusted based on the data. Vertical heat treatment apparatus 201 may be used.

[0011]

According to the vertical heat treatment apparatus of the present invention, even if the boat rises and approaches the opening of the core tube and the opening area becomes smaller, the inert gas supply amount from the gas supply port is correspondingly reduced. As a result, it is possible to prevent the inert gas blown from the opening from contaminating the semiconductor wafer, jigs and the like without sowing dust around the furnace tube.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an example of a vertical heat treatment apparatus according to the present invention.

FIG. 2 is a schematic cross-sectional view of a conventional vertical heat treatment apparatus.

FIG. 3 is a schematic cross-sectional view of another vertical heat treatment apparatus according to the present invention.

FIG. 4 is a schematic cross-sectional view of a conventional vertical heat treatment apparatus.

[Explanation of symbols]

 101, 201 Vertical heat treatment apparatus 102 Position detection unit 103 Gas amount adjustment unit 202 Flow velocity detection unit

Claims (3)

[Claims] A plurality of semiconductor wafers mounted on a boat;
The vertical furnace tube having a heating means disposed on the outside is allowed to enter from below, and the air in the vertical furnace tube is replaced with an inert gas to open the vertical furnace tube at a hatch portion at the bottom of the boat. A vertical heat treatment apparatus for performing a heat treatment of a semiconductor wafer by closing a portion thereof, comprising a control mechanism for controlling a supply amount of an inert gas in accordance with a lifting operation of the boat. 2. A position detecting unit for detecting a position of a hatch portion with respect to an opening of a vertical furnace core tube, and a control unit for controlling an inert gas blown out from the opening to a predetermined flow rate based on the detection data. The vertical heat treatment apparatus according to claim 1, further comprising a gas amount control unit that controls an inert gas supply amount. 3. A flow rate detecting section provided near the opening of the vertical core tube for detecting a flow rate of an inert gas blown out from the opening, and a control mechanism for determining the flow rate based on the detection data. 2. The vertical heat treatment apparatus according to claim 1, further comprising a gas amount adjusting unit for controlling an inert gas supply amount so as to obtain the above value.