JPH0378226A - Vertical heat-treating furnace - Google Patents

Abstract

PURPOSE:To enable uniform heat treatment by putting a core tube placed on the support table for a heat treating jig in a state of being surrounded by a soaking tube, heating unit materials and a heat insulating material, in a vertical heat treating furnace which treats semiconductor wafers. CONSTITUTION:A core tube 50 placed on the support table 30 for a heat treating jig 42 is put in a required gas-flow atmosphere by a gas supplying and discharging device 90, in a state of being surrounded by a soaking tube 60, heating unit materials 70, and a heat insulating tube 80, and wafers are heat-treated. This constitution prevents the occurrence of cold regions, etc., inside the core tube and besides performs good gas convection without disturbance. Accordingly, it becomes possible to heat-treat the wafers uniformly.

Description

Detailed Description of the Invention (1) Purpose of the Invention [Field of Industrial Application] The present invention relates to a vertical heat treatment furnace, and in particular, the present invention relates to a vertical heat treatment furnace. The present invention relates to a vertical heat treatment furnace in which semiconductor wafers are heat-treated in a state where the furnace core tube and support table are surrounded by a soaking tube, a heating member, and a heat insulating tube.

[Prior Art] Conventionally, in this type of vertical heat treatment furnace, a heavy semiconductor substrate is placed in the inner space of a furnace core tube that is surrounded by a soaking tube, a heating member, and a heat insulating tube and is supplied with heat treatment gas. It has been proposed that the wafer heat treatment jig is supported by a wafer heat treatment jig on the furnace lid body, and the wafer heat treatment jig is accommodated together with a support table that supports the wafer heat treatment jig, thereby performing appropriate heat treatment. It had been.

[Problems to be solved] However, in conventional vertical heat treatment furnaces, the wafer heat treatment jig was housed in the inner space of the furnace core tube together with the support table during heat treatment of semiconductor wafers. There is a drawback that not only a soaking area (low temperature area) is formed in the internal space, but also a turbulent flow of the heat treatment gas occurs in the internal space of the furnace core tube.
1) There is a drawback that a uniform heat-treated film cannot be formed on the surface of a semiconductor wafer.

In addition, in conventional vertical heat treatment furnaces, a support table is housed in the inner space of the furnace core tube during heat treatment of semiconductor wafers, so (iii) there is a drawback that heat treatment gas tends to stagnate in the inner space of the furnace core tube. In addition, there was a drawback that the discharge of the (ivl heat treatment gas) was inhibited and dust was likely to accumulate.

Therefore, the present invention aims to eliminate these drawbacks (by placing the furnace core tube directly on the support table on which the wafer heat treatment jig is placed, and by connecting the furnace core tube and support table to the soaking tube and the heating member). It is an object of the present invention to provide a vertical heat treatment furnace in which a semiconductor wafer is heat-treated while being surrounded by a heat treatment furnace and a heat insulating tube.

(2) Structure of the Invention [Means for Solving the Problems] The means for solving the problems provided by the present invention is as follows. In a vertical heat treatment furnace in which semiconductor wafers are heat treated by being supported and housed in a wafer heat treatment jig on a support table, the furnace core tube is used to place the wafer heat treatment jig. vertical heat treatment, characterized in that the semiconductor wafer is heat treated with the furnace core tube and the support table surrounded by a soaking tube, a heating member, and a heat insulating tube. ``furnace.''

[Function] The vertical heat treatment furnace according to the present invention performs wafer heat treatment on a table that supports semiconductor wafers in the inner space of the furnace core tube, which is surrounded by a soaking tube, a heating member, and a heat insulating tube and is supplied with heat treatment gas. A vertical heat treatment furnace that performs heat treatment by being supported and housed in a wafer heat treatment jig, and in particular, the furnace core tube is placed on a support table on which a wafer heat treatment jig is placed, and the furnace core is Since the semiconductor wafer is heat-treated while the tube and support table are surrounded by the soaking tube, the heating member, and the heat insulating tube, (1) formation of a low-temperature region in the internal space of the furnace core tube is avoided; (iii) It has the effect of suppressing the occurrence of turbulent flow of the heat treatment gas in the internal space of the fiil furnace core tube, and (iii) prevents the generation of stagnation of the heat treatment gas in the internal space of the furnace core tube. In other words, (iv) it has the effect of improving the discharge of the heat treatment gas and suppressing the accumulation of dust, and (v) it has the effect of quickly exchanging the heat treatment gas in the internal space of the furnace core tube. Eggplant.

[Example] Next, the vertical heat treatment furnace according to the present invention will be specifically described with reference to the accompanying drawings, citing preferred examples thereof. However, the examples described below are described to facilitate or accelerate understanding of the present invention, and are not described to limit the present invention. In other words, each member disclosed in the embodiments described below includes all design changes and equivalent substitutions that fall within the spirit and technical scope of the present invention.

"Earth Removal 1" With the semiconductor wafer supported on the support member 40, the furnace core tube concave is placed on the support table concave, and the soaking tube, heating member, and heat insulating tube are lowered to near the upper surface of the base. A state in which the tube 50 is surrounded is shown.

First, the configuration of an embodiment of a vertical heat treatment furnace according to the present invention will be described in detail with reference to FIG.

Reference numeral 10 denotes a vertical heat treatment furnace according to the present invention, which is placed on a base plate made of a suitable material such as quartz, and a base plate made of a suitable material such as quartz. A support table 30, a wafer support member 40 which is placed on the support table during heat treatment of the semiconductor wafer, and on which the semiconductor wafer is supported in a well-known manner; A furnace core tube 50 formed of a suitable material such as quartz for surrounding the cage wafer support member 40 and an opening 61 arranged around the support table recess and the furnace core tube recess during heat treatment of semiconductor wafers. A heating member 70 is arranged around the heat equalizing tube 60 and connected to an appropriate external power source, and the heating member 70 is arranged on the inner surface. A heat insulating tube 80 for supporting the soaking tube or the like by a support portion 81 formed on the end face of the opening, and a heat insulating tube 80 that is disposed passing through the base 20 and the support table 30, and is arranged to penetrate the inner space of the furnace core tube 50 and Furnace core tube 50
A gas supply/discharge device 90 is provided for supplying appropriate heat treatment gas (for example, hydrogen gas or oxygen gas) and atmospheric gas (for example, nitrogen gas) to the space between the heat soaking tube 60 and the heat soaking tube 60, respectively.

The base 20 has protrusions 21 formed to surround the opening 61 of the soaking tube 60 at intervals, and is open to the space surrounded by the protrusions 21 to discharge high-temperature heat treatment gas. It is equipped with a gas exhaust pipe 22 for
While ensuring an exhaust path for the atmospheric gas to the internal space of the device, the high temperature heat treatment gas is prevented from flowing out and coming into contact with the elevating means 83 of the heat insulating pipe 80 or the wafer transport device (not shown) disposed around the device. is being prevented.

The support table 30 includes a plurality of heat shield plates 31 supported by a plurality of support columns 32 at appropriate intervals, and the uppermost heat shield plate 31 is connected to the opening of the furnace core tube 50. 51 by a friction surface.

The wafer support member 40 is made of a suitable material such as quartz, and is mounted on a placement table 41 placed on the support table 30.
and a wafer heat treatment jig 42, which is placed on the placement table 41 by a first transfer means (not shown) and is made of a suitable material such as quartz, on which the semiconductor wafer is placed for heat treatment. It encompasses.

The furnace core tube 50 has an appropriate shape (for example, a bell jar shape), and has a guide passage 52 formed on its inner surface for guiding the heat treatment gas supplied by the gas supply/discharge device to the top. The furnace core tube 50 is also formed with a protrusion 53 on its outer peripheral surface, which is engaged with a second transfer means (not shown) when placed on the support table 4 and removed from the support table 4. has been done.

The soaking tube 60 is made of silicon carbide, for example, and is arranged to surround the entire length of the support table 30 and the furnace core tube 50. A protrusion 62 is formed on the outer peripheral surface of the opening 61, which is comparable to that of a heat soaking tube, for engaging with a support portion 81 formed on the end surface of the opening of the heat insulating tube 80.

The heating members are appropriately arranged in the internal space of the heating tube along the axial direction (that is, in the vertical direction) to ensure a heating area.

The heat insulating tube is made of a suitable material such as glass fiber, and the furnace core tube 50. It surrounds the soaking tube 60 and the heating member 70 as a whole. The heat insulating pipe 80 has support members 82A and 82B attached to its upper and lower outer sides, respectively, and is engaged by a lifting means 83 so as to be able to rise and fall.

The gas supply and discharge device 90 includes a base 20 and a support table 30.
A heat treatment gas (for example, hydrogen gas or oxygen gas) is supplied to the lower end of the guide passage 52 formed on the inner surface of the furnace core tube 4 from an appropriate gas supply source (not shown) through the heat shielding plate 31 of the furnace core tube 4. A gas supply pipe 91 for supplying gas, and a base 20
and the heat shielding plate 31 of the support table 30, and the used heat treatment gas is delivered to the furnace core tube 50 from the opening 51 of the furnace core tube 50.
A gas exhaust pipe 92 for discharging the gas to the outside passes through the base 20 and the heat shielding plate 31 of the support table 30 and is opened near the outer periphery of the opening 51 of the furnace core tube column to supply appropriate gas. Another gas supply pipe 93 is provided for supplying an appropriate atmospheric gas (for example, nitrogen gas) from a source (not shown) to the space between the furnace core tube column and the soaking tube column.

Further, with reference to FIG. 1, the operation of an embodiment of the vertical heat treatment furnace according to the present invention will be described in detail.

After the semiconductor wafer to be heat treated is supported, the wafer heat treatment jig 42 for the wafer is rotated in the lateral direction while the first transfer means is held by its transfer arm, so that the support table is rotated. 30 is placed above the placement table 41. After reaching above the placement table 41, the wafer heat treatment jig 42 is lowered by lowering the transfer arm of the first transfer means, and is lowered to the top of the placement table 41.
be placed on top. The transport arm of the first transport means is then lowered slightly to the wafer heat treatment jig 42.
The robot is then moved laterally and retracted to its original standby state.

Next, the furnace core tube 50 is rotated laterally from the standby state to above the support table 30 (and thus the wafer heat treatment jig 42) by having its protrusion 53 supported by the transfer arm of the second transfer means. be moved. The furnace core tube 50 is
Thereafter, it is lowered by lowering the transport arm of the second transport means, and is placed on the upper surface of the heat shield plate 31 at the top of the support table 30. Furnace core tube 5
When the opening 51 of No. 0 comes into contact engagement with the rubbing surface 31a of the heat shielding plate 31, the conveying arm of the second conveying means is slightly lowered and separated from the protrusion 53, and further moved laterally. ,
It is evacuated to the initial standby state.

Furthermore, the support members 82A and 82B are moved by the lifting means 83.
By driving the soaking tube 60. The heating member 70 and the heat insulating pipe column are moved from the standby state in the direction of arrow x1. The elevating means 83 stops the soaking tube, the heating member U, and the heat insulating pipe column in a state where the opening 61 of the heat soaking tube 60 reaches near the top surface of the base plate. At this time, the heating members are connected to an appropriate power source and form a soaking area at a desired temperature inside the heat soaking tube column prior to the start of the semiconductor wafer mounting operation.

The wafer heat treatment gas supply/discharge unit supplies an appropriate atmospheric gas through a gas supply pipe 93 prior to the start of the semiconductor wafer mounting operation in order to remove dust generated during the semiconductor wafer mounting operation. We are starting to supply This results in
When the semiconductor wafer placement operation is completed, atmospheric gas fills the space between the furnace core column and the soaking tube, and finally the end face of the opening 61 of the soaking tube and the base. The gas passes between the upper surface of the tube and begins to be discharged to the outside of the soaking tube column via the gas discharge pipe 22.

After the semiconductor wafer mounting operation is completed, the gas supply and discharge device concavity starts supplying heat treatment gas to the lower end of the guide passage 52 formed on the inner surface of the furnace core tube column through the gas supply pipe 91, and discharges the gas. The tube 92 begins to discharge the spent heat treatment gas from the interior space of the furnace core tube 50 to the outside of the soaking tube column. As a result, in the furnace core tube column, the heat treatment gas is guided to the top of the internal space by the guide passage 52, and then begins to be released near the top of the wafer heat treatment jig 42, and is After passing through the vicinity of the semiconductor wafer), the gas reaches the upper surface of the support table 30 and begins to be discharged to the outside of the soaking tube 60 via the gas discharge tube 92.

By maintaining the wafer heat treatment jig 42, furnace core tube, etc. in this state for an appropriate period of time,
Heat treatment of the semiconductor wafer is performed.

゛ When the heat treatment of the semiconductor wafer is completed, the gas supply/discharge device 90 stops supplying the heat treatment gas through the gas supply pipe 91.

After that, the lifting means 83 moves the supporting members 82A and 82B.
, the soaking tube recess, the heating member U, and the heat insulating tube are moved upward as shown by arrow x2, and placed in a standby state.

Furthermore, after the second conveyance means supports the protrusion 53, which is similar to a furnace core tube, with its conveyance arm and moves it upward,
Rotate horizontally to standby.

Finally, the first transfer device holds the wafer heat treatment jig 42 with its transfer arm, moves it upward, and then rotates it in the horizontal direction, thereby transferring the wafer heat treatment jig 42 to the vertical heat treatment furnace according to the present invention. Take it out.

As is clear from the above-described embodiments, the vertical heat treatment furnace 10 according to the present invention includes a wafer heat treatment jig 42.
The support table 30 is placed directly on the support table 30 on which the furnace core tube section is placed, and the furnace core tube section and the support table section are surrounded by the soaking tube section, the heating member 4, and the heat insulating tube column. The heat treatment gas is directly supplied to the inner space of the furnace core tube 50 by the gas supply/discharge device 90 disposed through the furnace core tube, and the used heat treatment gas is directly discharged from the inner space of the furnace core tube. Wafer heat treatment jig 4
2, the formation of a low-temperature region in the internal space of the fiil furnace tube can be avoided, and as a result, the heat treatment gas can be prevented from being formed in the fiil furnace core tube space. It is possible to suppress the occurrence of turbulent flow,
In addition, fiii) it is possible to suppress the heat treatment gas from stagnation in the internal space of the furnace core tube, in other words, it is possible to improve the discharge of the heat treatment gas (ivl), and to suppress the accumulation of dust;
v) The heat treatment gas can be quickly exchanged in the inner space of the furnace core tube.

In addition, with reference to FIG. 1, the vertical heat treatment furnace according to the present invention will be described with reference to specific numerical values for a better understanding.

100% by the gas supply pipe 91 of the gas supply and discharge device
A semiconductor wafer having a diameter of 5 inches was heat-treated while supplying oxygen gas as a heat-treating gas into the furnace core tube 5o. The heat treatment temperature was 1000'C when measured at the outside of the soaking tube at 6°. Moreover, the heat treatment time was 3 hours.

A uniform oxide film was formed on the semiconductor wafer.

The thickness of the oxide film is 1 at the position corresponding to the center of the furnace core tube.
040±2.5 people, and 1041±3.3 people at the position corresponding to the peripheral part of the furnace core tube 50.

The wafer heat treatment jig supporting the semiconductor wafer is placed on the furnace lid body, and the support table supporting the wafer heat treatment jig is placed in the inner space of the furnace core tube to which heat treatment gas is supplied. By accommodating the semiconductor wafer in the wafer, heat treatment of the semiconductor wafer was performed under the same conditions as in the example.

The thickness of the oxide film formed on the semiconductor wafer was 1041±5.9 mm at the position corresponding to the center of the furnace core tube.
It was 1,045±l ro 1 ro at a position corresponding to the peripheral part of the furnace core tube.

As is clear from the above-mentioned examples and comparative examples, according to the vertical heat treatment furnace IO according to the present invention, the oxide film at the position corresponding to the center of the furnace core tube is reduced. It is possible to eliminate the defect that the thickness of the oxide film is smaller than the thickness of the oxide film at the position corresponding to the peripheral part, and the variation in the thickness of the oxide film at the position corresponding to the center of the furnace core tube is smaller than that of the peripheral part. It was possible to suppress the drawback of large variations in the thickness of the oxide film at positions corresponding to the oxide film.

(3) Effects of the invention As is clear from the above, the vertical heat treatment furnace according to the present invention has an inner space of the furnace core tube surrounded by the soaking tube, the heating member, and the heat insulating tube, and to which the heat treatment gas is supplied. On the other hand, it is a vertical heat treatment furnace in which semiconductor wafers are heat-treated by being supported and housed in a wafer heat treatment jig on a support table, and in particular, the furnace core tube is a support on which a wafer heat treatment jig is placed. Since the semiconductor wafer is heat-treated while placed on the table and the furnace core tube and support table are surrounded by the soaking tube, the heating member, and the heat insulating tube, (1) Internal space of the furnace core tube. It has the effect of being able to avoid the formation of a low temperature area in It has the effect of suppressing the accumulation of heat treatment gas in the internal space, in other words, it has the effect of improving the discharge of the heat treatment gas and suppressing the accumulation of dust. This has the effect of quickly exchanging heat treatment gas.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a vertical heat treatment furnace according to the present invention. 10...... Vertical heat treatment furnace 20... Base 21...
・・・・・・・・・Protrusion 22・・・・・・・・・
...Gas exhaust pipe 30...
・Support table 31...Heat shield plate 32...Support column 40
・・・・・・・・・・・・・・・Wafer support member 41・・・・・・・・・・・・・・・・Arrangement table 42・
......... Wafer heat treatment jig 50 ...... Furnace core tube 51 ...
・・・・・・・・・Opening 52・・・・・・・
......Guidance passage 53...
...Protrusion 60 ..... Soaking tube 61 ..... Opening 62 ...
......Protrusion 70...Heating member 80...
・・・・・・・・・・・・・・・・・・Insulated pipe 81...
・・・・・・・・・・・・Support parts 82A, 82B・
......Supporting member 83...90...91...91...92...93... ... Lifting means ... Gas supply and discharge device ... Gas supply pipe ... Gas discharge pipe ... Gas supply pipe

Claims (1)

[Claims] Heat treatment is performed by supporting and housing a semiconductor wafer in a wafer heat treatment jig on a support table in the inner space of a furnace core tube surrounded by a soaking tube, a heating member, and a heat insulating tube and supplied with heat treatment gas. In a vertical heat treatment furnace, a furnace core tube is placed on a support table on which a wafer heat treatment jig is placed, and the furnace core tube and support table are surrounded by a soaking tube, a heating member, and a heat insulating tube. A vertical heat treatment furnace characterized in that heat treatment of semiconductor wafers is performed in a state in which semiconductor wafers are heated.