JP2002093730A - Semiconductor wafer diffusion device and method of manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor wafer diffusion device and a method of manufacturing a semiconductor device, with which entrainment of the atmosphere into a diffusion furnace can be prevented, when a semiconductor wafer is inserted into the furnace. SOLUTION: The semiconductor wafer diffusion device is equipped with a diffusion furnace 1 for performing diffusion treatment or oxidation treatment of a semiconductor wafer, a first gas inlet port 3 provided at an end of the diffusion furnace for introducing a first inert gas into the diffusion furnace, an insertion port provided at the other end of the diffusion furnace for inserting a board 7 on which a plurality of semiconductor wafers 5 are arranged and placed, a shutter for opening/closing this insertion port, a heater 9 disposed around the diffusion furnace, a second gas inlet 4 provided on a side surface on the other end side of the diffusion furnace for introducing a second inert gas into the diffusion furnace, and a gas discharge port 6 provided on a side surface on the other end side of the diffusion furnace and opposed to the second gas inlet port.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffusion apparatus used in a diffusion step or an oxidation step in a semiconductor wafer, and
The present invention relates to a method for manufacturing a semiconductor device for diffusing or oxidizing a semiconductor wafer.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view schematically showing a conventional semiconductor wafer diffusion apparatus. Semiconductor wafer diffusion device 1
Reference numeral 00 denotes a diffusion furnace 101 made of quartz having a tube shape. Diffusion furnace 101 has an inner diameter larger than the diameter of the main surface of semiconductor wafer 105.

[0003] At the tail tube side (one end) of the diffusion furnace 101, a gas inlet 103 for introducing an inert gas such as nitrogen gas into the furnace as shown by an arrow 102 is provided. A pipe (not shown) for supplying an inert gas to the gas inlet 103
It is connected to the. On the head tube side (the other end) of the diffusion furnace 101, a board insertion port for inserting a quartz board 107 on which a plurality of semiconductor wafers 105 are placed side by side into the furnace is provided. A shutter (not shown) is attached to the board insertion opening so as to be freely opened and closed. Further, a heater 109 is arranged on the outer peripheral portion of the diffusion furnace 101 so as to surround the outside of the furnace.

Next, a procedure for performing an oxidation step on a wafer using the above-described semiconductor wafer diffusion apparatus will be described.

[0005] First, the diffusion furnace 101 is heated by the heater 109, and, for example, nitrogen gas is introduced into the furnace from the gas inlet 103 as shown by an arrow 102. Then, the inside of the diffusion furnace 101 is set to a nitrogen gas atmosphere, and the temperature in the furnace is raised to a predetermined temperature (for example, 1000 ° C.).

After that, the shutter is opened to open the board insertion opening. Next, a plurality of semiconductor wafers 105 are placed on the board 107, and the board 107 is inserted into the furnace using a jig such as a fork (not shown). Next, the shutter is closed and the board insertion port is closed. Thereafter, this state is maintained for a predetermined time until the furnace temperature reaches a predetermined temperature (for example, 1000 ° C.).

Next, the introduction of nitrogen gas into the furnace is stopped,
An oxidizing atmosphere gas containing a predetermined concentration of oxygen is supplied to the gas inlet 10.
3 and introduced into the furnace. Thereafter, the surface of the semiconductor wafer 105 is subjected to an oxidizing process by maintaining this state for a predetermined time.

[0008]

In the conventional semiconductor wafer diffusion apparatus 100, when the wafer 105 is inserted into the furnace, the temperature in the furnace is maintained at a predetermined temperature. The atmosphere inside the furnace causes the temperature in the furnace to drop below a predetermined temperature. Therefore, before the wafer is subjected to the oxidation treatment, it is necessary to hold the same for a predetermined time until the furnace temperature reaches the predetermined temperature. Therefore, such a holding time takes a long time, so that the throughput is deteriorated.

Further, since the amount of air entrained when a wafer is inserted into the furnace is not always constant, when the amount of air entrained is large, the air at the mouth of the diffusion furnace 101 (in the vicinity of the board insertion port) may be reduced. The temperature drops more than expected,
Even when oxidizing the wafer, the temperature uniformity in the furnace may be poor. As a result, the temperature within the wafer surface becomes non-uniform, and if the oxidation treatment is performed in this state, the thickness of the oxide film formed on the wafer may become non-uniform, or the quality of the oxide film may deteriorate.

In addition, by inserting air into the furnace when inserting the wafer into the furnace, even after inserting the board into the furnace,
Atmosphere remains between a plurality of wafers mounted on the board. Since the nitrogen gas flows in the furnace as indicated by the arrow 111, it is difficult for the nitrogen gas to be particularly replaced between the wafers. Therefore, even when the oxidation process is performed on the wafer after the board is inserted, the residual air may remain. If the oxidation treatment is performed in this state, the thickness of the oxide film formed on the wafer may be uneven or the quality of the oxide film may be deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a semiconductor wafer which can suppress the entrapment of air into a furnace when the semiconductor wafer is inserted into the furnace. And a method of manufacturing a semiconductor device.

[0012]

In order to solve the above problems, a semiconductor wafer diffusion apparatus according to the present invention is provided with a diffusion furnace for performing a diffusion process or an oxidation process on a semiconductor wafer, and a diffusion furnace provided at one end of the diffusion furnace. A first gas inlet for introducing a first inert gas into the diffusion furnace, and a first gas inlet provided at the other end of the diffusion furnace;
An insertion slot for inserting a board on which a plurality of semiconductor wafers are placed side by side, a shutter for opening and closing the insertion slot, a heater arranged on the outer periphery of the diffusion furnace, and a side surface on the other end side of the diffusion furnace are provided. A second gas inlet for introducing a second inert gas into the diffusion furnace, and a second gas introduction port provided on a side surface on the other end side of the diffusion furnace;
And a gas outlet arranged to face the second gas inlet. Preferably, the diffusion furnace has a tubular shape.

According to the above-described semiconductor wafer diffusion apparatus, the second gas inlet is provided on the side surface on the other end side of the diffusion furnace, and the gas outlet is provided at a position facing the second gas inlet. Therefore, when inserting the wafer placed on the board into the furnace,
The second inert gas can be introduced from the second gas inlet, and the introduced second inert gas can be discharged from the gas outlet. Therefore, it is possible to suppress the air from being entrained in the furnace when the wafer is inserted into the furnace.

Further, in the semiconductor wafer diffusion apparatus according to the present invention, the apparatus further includes a gas pipe having one end connected to the second gas inlet, and a part of the gas pipe is connected to the heater and the diffusion furnace. It is preferable to be arranged between them. Thus, the second inert gas that has passed through the gas pipe is heated by the heater, and the heated second inert gas can be introduced into the furnace from the second gas inlet.

In the apparatus for diffusing a semiconductor wafer according to the present invention, the second gas inlet and the gas outlet are preferably located between an end of the heater and the insertion port.

In the apparatus for diffusing a semiconductor wafer according to the present invention, the gas outlet may be located closer to the insertion port than the second gas inlet. Accordingly, even if the second inert gas introduced into the furnace from the second gas inlet is swept toward the insertion port by the first inert gas introduced into the furnace from the first gas inlet, 2 Inert gas can be discharged from the gas outlet.

Further, in the semiconductor wafer diffusion apparatus according to the present invention, a plurality of the gas discharge ports may be formed.

Further, in the semiconductor wafer diffusion device according to the present invention, a plurality of the second gas inlets may be formed.

Further, in the semiconductor wafer diffusion device according to the present invention, it is preferable that the size of the gas outlet is larger than the size of the second gas inlet.
Thereby, even if the second inert gas introduced from the second gas introduction port spreads, it can be smoothly discharged.

A method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a semiconductor device in which a semiconductor wafer is diffused or oxidized. The board on which a plurality of semiconductor wafers are arranged is diffused while flowing the first inert gas toward the second furnace and flowing the second inert gas from the side surface on the other end side of the diffusion furnace toward the side surface facing the first furnace. The method further comprises a step of inserting the other end of the furnace into the diffusion furnace.

According to the method of manufacturing a semiconductor device, the board is moved from the other end of the diffusion furnace to the other side of the diffusion furnace while flowing the second inert gas from the side face on the other end side of the diffusion furnace toward the side face opposite to the second inert gas. Insert inside. Therefore, it is possible to suppress the air from being entrained in the furnace when the wafer is inserted into the furnace.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a cross-sectional view schematically showing a semiconductor wafer diffusion device according to a first embodiment of the present invention, and FIG.
FIG. 1C is a cross-sectional view taken along the line b-1b, and FIG.
It is sectional drawing along the 1c-1c line shown to (a).

As shown in FIGS. 1 (a), 1 (b) and 1 (c), a semiconductor wafer diffusion apparatus 10 includes a quartz diffusion furnace 1 having a tube shape. Diffusion furnace 1 has an inner diameter larger than the diameter of the main surface of semiconductor wafer 5.

A first gas inlet 3 for introducing a first inert gas such as nitrogen gas into the furnace as shown by an arrow 2 is provided on the tail tube side (one end) of the diffusion furnace 1. The first gas inlet 3 is connected to a pipe (not shown) for supplying a first inert gas. On the head tube side (the other end) of the diffusion furnace 1, a board insertion port is provided for inserting a quartz board 7 on which a plurality of semiconductor wafers 5 are placed side by side into the furnace. A shutter (not shown) is attached to the board insertion opening so as to be freely opened and closed. Further, a heater 9 is arranged on the outer peripheral portion of the diffusion furnace 1 so as to surround the outside of the furnace.

A second gas inlet 4 for introducing a second inert gas such as nitrogen gas into the furnace is provided on a side surface on the other end side of the diffusion furnace 1.
Is provided. A gas outlet 6 is provided at a position facing the second gas inlet 4 on the side surface on the other end side of the diffusion furnace 1. Further, one end of a gas pipe 8 is connected to the second gas inlet 4, and the gas pipe 8 is disposed between the heater 9 and the diffusion furnace 1. Therefore, the second inert gas that has passed through the gas pipe 8 is heated by the heater 9, and the second inert gas that has been heated can be introduced from the second gas inlet 4 into the furnace.

The second gas inlet 4 and the gas outlet 6 are arranged between the end of the heater 9 and the board insertion port.
The straight line connecting the second gas inlet 4 and the gas outlet 6 may be located substantially perpendicular to the longitudinal direction of the diffusion furnace 1.

The gas outlet 6 is connected to the second gas inlet 4
May be arranged at a position closer to the board insertion slot.
Thereby, the second inert gas introduced into the furnace from the second gas inlet 4 is swept toward the board insertion port by the first inert gas introduced into the furnace from the first gas inlet 3. Also, the second inert gas can be discharged from the gas discharge port 6.

It is desirable that the size of the gas outlet 6 is the same as or larger than that of the second gas inlet 4. Thereby, even if the second inert gas introduced from the second gas introduction port 4 spreads, it can be smoothly discharged.

Next, a procedure for performing an oxidation step or a diffusion step on a wafer using the above-described semiconductor wafer diffusion apparatus will be described.

First, the diffusion furnace 1 is heated by the heater 9 and, for example, nitrogen gas is introduced into the furnace from the first gas inlet 3 as shown by an arrow 2. Then, the inside of the diffusion furnace 1 is set to a nitrogen gas atmosphere, and the temperature in the furnace is raised to a predetermined temperature (for example, 1000 ° C.).

Thereafter, as shown in FIG. 1A, nitrogen gas is introduced into the furnace from the second gas inlet 4 through the gas pipe 8 as indicated by an arrow 12, and the introduced nitrogen gas is supplied by an arrow 13 as shown in FIG. To the gas outlet 6.

Next, the shutter is opened to open the board insertion opening. Thereafter, the plurality of semiconductor wafers 5 are placed on the board 7, and the board 7 is inserted into a furnace using a jig such as a fork (not shown) as shown in FIGS.
At this time, the nitrogen gas introduced into the furnace from the first gas inlet 3 is flowing from the tail tube side (one end) to the head tube side (the other end) in the diffusion furnace, in a direction crossing this flow. Nitrogen gas is also flown like a curtain (in the direction of arrow 13 from second gas inlet 4 to gas outlet 6). Therefore, it is possible to suppress the air from being entrained in the furnace when the wafer is inserted by the nitrogen gas flowing like the curtain.

Next, the shutter is closed to close the board insertion opening. Thereafter, the introduction of nitrogen gas into the furnace from each of the first gas inlet 3 and the second gas inlet 4 is stopped,
An oxidizing atmosphere gas containing a predetermined concentration of oxygen is introduced from the first gas inlet 3 into the furnace. Next, the surface of the semiconductor wafer 5 is subjected to an oxidation treatment by maintaining this state for a predetermined time.

According to the first embodiment, the board 7
When the wafer 5 placed on the wafer is inserted into the furnace, nitrogen gas is introduced from the second gas inlet 4, and the introduced nitrogen gas is discharged from the gas outlet 6. For this reason, when the wafer is inserted into the furnace, entrainment of the atmosphere into the furnace can be suppressed. Therefore, it is possible to suppress a decrease in the furnace temperature maintained at the predetermined temperature, and to enhance the heat retention at the mouth of the diffusion furnace. As a result, since the wafer can be oxidized or diffused relatively soon after the wafer is inserted into the furnace, the throughput can be improved as compared with the conventional semiconductor wafer diffusion apparatus.

Further, when the wafer 5 is inserted into the furnace, the air entrained in the furnace can be suppressed, so that the temperature at the mouth of the diffusion furnace 1 (in the vicinity of the board insertion port) is prevented from lowering. Can be. Therefore, it is possible to improve the temperature uniformity in the furnace when performing the oxidation process or the diffusion process on the wafer 5. As a result, the temperature uniformity in the wafer surface is improved, and when the oxidation treatment is performed in this state, the thickness uniformity of the oxide film formed on the wafer can be improved,
The quality of the oxide film can be improved.

Further, by preventing the atmosphere from being entrained in the furnace when inserting the wafers 5 into the furnace, after the board 7 is inserted into the furnace, a plurality of wafers 5 placed on the board 7 can be removed. It is possible to suppress the air from remaining between them. That is, the nitrogen gas from the first gas inlet 3 is
As shown in (b), since the gas flows in the furnace as indicated by the arrow 15, it is difficult to replace the wafers with nitrogen gas, especially between the wafers. However, since the nitrogen gas from the second gas inlet 4 flows in the furnace as shown by an arrow 13 as shown in FIG. 1 (a), when the wafer 5 is inserted into the furnace, the nitrogen gas The air existing between each other can be swept away and exhausted reliably. Therefore, it is possible to prevent the air from remaining between the wafers when performing the oxidation process on the wafer after the board is inserted. Therefore, the thickness uniformity of the oxide film formed on the wafer can be improved, and the deterioration of the oxide film quality can be suppressed.

FIG. 2 is a cross-sectional view of a diffusion furnace corresponding to FIG. 1C, and illustrates a semiconductor wafer diffusion apparatus according to a second embodiment of the present invention. The description of the same parts as in the first embodiment is omitted.

Three second gas inlets 4 are formed on the side surface on the other end side of the diffusion furnace 1. Three gas outlets 6 are formed on the side surface on the other end side of the diffusion furnace 1.

The same effects as those of the first embodiment can be obtained in the second embodiment. Also, the second
In the embodiment, the second gas inlet 4 and the gas outlet 6
Since each of the three is formed, entrainment of the atmosphere can be further suppressed as compared with the first embodiment.

The present invention is not limited to the above embodiment, but can be implemented with various modifications. For example,
The shapes of the second gas inlet 4 and the gas outlet 6 are preferably round, but various shapes can be used.

In the second embodiment, three second gas inlets 4 and three gas outlets 6 are formed. However, the number of the second gas inlets 4 and the number of gas Is not particularly limited. That is, the second
It is also possible to form two or four or more gas inlets 4 and gas outlets 6, respectively, and the number of second gas inlets 4 and the number of gas outlets 6 may be different. For example, one second gas inlet 4 may be formed, and a plurality of gas outlets 6 may be formed.

In the above embodiment, the present invention is applied to a horizontal diffusion furnace, but the present invention can also be applied to a vertical diffusion furnace.

[0043]

As described above, according to the apparatus for diffusing a semiconductor wafer according to the present invention, the second gas inlet is provided on the side surface on the other end side of the diffusion furnace, and the position opposed to the second gas inlet is provided. Is equipped with a gas outlet. Therefore, when the semiconductor wafer is inserted into the diffusion furnace, it is possible to suppress the air from being caught in the furnace.

According to the method of manufacturing a semiconductor device of the present invention, the inside of the diffusion furnace is heated to a predetermined temperature, the first inert gas is flowed from one end to the other end in the diffusion furnace, and the diffusion furnace is heated. A board on which a plurality of semiconductor wafers are placed is inserted into the diffusion furnace from the other end of the diffusion furnace while flowing the second inert gas from the side surface on the other end side to the side surface opposite to the second inert gas. Therefore, when the semiconductor wafer is inserted into the diffusion furnace, it is possible to suppress the air from being caught in the furnace.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view schematically showing a semiconductor wafer diffusion device according to a first embodiment of the present invention;
(B) is a sectional view taken along line 1b-1b shown in (a), and (c) is a sectional view taken along line 1c-1c shown in (a).

FIG. 2 is a sectional view of a diffusion furnace corresponding to FIG. 1 (c),
FIG. 9 illustrates a semiconductor wafer diffusion device according to a second embodiment of the present invention.

FIG. 3 is a sectional view schematically showing a conventional semiconductor wafer diffusion apparatus.

[Explanation of symbols]

 1, 101: diffusion furnace 2, 102: arrow 3: first gas inlet 4: second gas inlet 5, 105: semiconductor wafer 6: gas outlet 7, 107: board 8: gas pipe 9, 109: heater 10, 100: semiconductor wafer diffusion device 12, 13, 15, 111: arrow 103: gas inlet

Claims (9)

[Claims] A diffusion furnace for performing a diffusion process or an oxidation process on a semiconductor wafer; a first gas inlet provided at one end of the diffusion furnace for introducing a first inert gas into the diffusion furnace; An insertion slot provided at the other end of the substrate for inserting a board on which a plurality of semiconductor wafers are arranged and arranged; a shutter for opening and closing the insertion slot; a heater arranged on the outer periphery of the diffusion furnace; and the other end of the diffusion furnace. The second inside the diffusion furnace provided on the side
A second gas inlet for introducing an inert gas; and a gas outlet provided on a side surface at the other end of the diffusion furnace and arranged to face the second gas inlet. Semiconductor wafer diffusion device. 2. The apparatus according to claim 1, further comprising a gas pipe having one end connected to the second gas inlet, a part of the gas pipe being disposed between the heater and the diffusion furnace. Item 2. The semiconductor wafer diffusion device according to Item 1. 3. The semiconductor wafer according to claim 1, wherein the second gas inlet and the gas outlet are located between an end of the heater and the insertion port. Spreader. 4. The semiconductor according to claim 1, wherein the gas outlet is located closer to the insertion port than the second gas inlet. Wafer diffusion device. 5. The semiconductor wafer diffusion apparatus according to claim 1, wherein a plurality of said gas outlets are formed. 6. The semiconductor wafer diffusion device according to claim 5, wherein a plurality of said second gas introduction ports are formed. 7. The apparatus according to claim 1, wherein the size of the gas outlet is larger than the size of the second gas inlet. . 8. The apparatus according to claim 1, wherein the diffusion furnace has a tubular shape. 9. A method for manufacturing a semiconductor device for diffusing or oxidizing a semiconductor wafer, comprising: elevating a temperature inside a diffusion furnace to a predetermined temperature and flowing a first inert gas from one end to the other end in the diffusion furnace. While flowing and flowing the second inert gas from the side surface on the other end side of the diffusion furnace toward the side surface opposite thereto, a board on which a plurality of semiconductor wafers are placed side by side is introduced into the diffusion furnace from the other end of the diffusion furnace. A method for manufacturing a semiconductor device, comprising a step of inserting.