JPS61190929A - Treatment device - Google Patents

Abstract

PURPOSE:To prevent an oxide film from being grown by atmosphere on a processed member arranged in a processor by means of providing an inlet of processing chamber with an atmospheric inflow preventing device. CONSTITUTION:Hot blast of gas to be reacted etc. is blown from an inlet 14 side of a reaction tube 11 to a case body 16 of an atmospheric inflow preventing device 15. At this time, the hot blast is convected in the first gas shower chamber 19 to feed a part of hot blast to the second gas shower chamber 20 further to the third gas shower chamber 21. However, the hot blast is cooled down by the convection in N2 gas from the other gas shower chambers 25, 26 to minimize the temperature difference in the part near an opening part coming into contact with the atmosphere outside the last shower chamber 21. Through these procedures, any atmospheric inflow may be prevented effectively from occuring without providing the opening part 33 with a door to shield the atmosphere since there is no convection due to hot blast at all in the third gas shower chamber 21.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is applicable to diffusion furnaces and horizontal CVD (Cbemical
The present invention relates to a processing device such as a vapor deposition device, and particularly to a processing device that prevents outside air from being drawn into the interior by convection.

[Background technology]

In a conventional diffusion furnace, as shown in FIG. 6, a quartz port 3 in which wafers 2 are arranged is arranged in a reaction tube l serving as a processing chamber, and this reaction tube 1 is connected to a heater (for example, a resistance heater) 4. The reactant gas (or reactant gas and N2 gas) is introduced from the back of the furnace through the gas introduction pipe 5, and predetermined reaction treatments (for example, impurity diffusion treatment, oxide film formation treatment, etc.) are performed at a predetermined temperature. .

Since the furnace mouth, that is, the inlet 6 of the reaction tube 1, is not provided with a lid, outside air (outside air) is drawn into the reaction tube 1 from here, and as a result, an unintended oxide film is deposited on the wafer 2.
Since it grows upwards, various countermeasures are being taken.

As one of the countermeasures, as shown in the same figure, in a steady state, Nt gas is flowed from the gas introduction vibrator 5 toward the furnace mouth, that is, toward the inlet 6 of the reaction tube 1, and a scavenger installed at the inlet 6 of the reaction tube 1 is used. The NZ gas is exhausted as shown by the arrow by a thermal exhaust device 7, together with outside air (atmosphere) that is drawn in from the furnace mouth by convection. is prevented from growing.

In addition, as one of the above-mentioned measures, as shown in FIG. 7, a shower device 8 for blowing out N2 gas is provided at the furnace mouth, that is, the inlet 6 of the reaction tube 1, and the shower device 8 allows the N2 gas to flow out like a curtain. This prevents outside air from being drawn into the reaction tube 1.

However, in any of the above measures, a large flow rate of Nt gas is required. In addition, due to the need to increase the number of chips on a wafer, the diameter of the wafer becomes larger, and the diameter of the reaction tube 1 increases accordingly.
To prevent an oxide film from growing on the wafer placed in the reaction tube 1 due to unintended atmospheric air, since the opening area of the reaction tube 1 becomes large and none of the above measures can sufficiently prevent outside air from being drawn in. become unable to do so.

Although the above is a case of a diffusion furnace, the same can be said of a horizontal CVD apparatus. In other words, in the case of a horizontal CVD apparatus, the inlet cover is opened when loading and unloading wafers into the reaction tube serving as a processing chamber, and as a result, an unintended oxide film may grow on the wafer due to outside air being drawn in. Similar measures are being taken. However, in this case, the same problem as in the case of the diffusion furnace described above occurs, and in addition, since the temperature is low at the exhaust side end of the reaction tube away from the heater, the CVD film etc. attached to the tube wall may be removed from the wafer. Gas for preventing outside air entrainment (a gas for expelling outside air that is drawn in) is introduced from the exhaust side to expel the outside air that is drawn in when loading and unloading the wafer. This is undesirable as it causes foreign matter to get onto the wafer.

[Purpose of the invention]

An object of the present invention is to prevent outside air from being drawn into the processing chamber, thereby preventing the growth of an oxide film due to outside air (atmospheric air) on the workpieces placed inside the processing chamber, and to The flow rate of the outside air entrainment prevention gas flowing toward the inlet on the other end side can be reduced, especially for horizontal C
In the case of a VD device, the object is to provide a processing device that can prevent dust generation inside a processing chamber.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, in addition to performing a predetermined reaction treatment (for example, impurity diffusion treatment) on the member to be processed in the processing chamber, at least when the member to be processed is taken in and out, a gas for preventing outside air from being drawn in is passed from one end of the processing chamber to the other end of the processing chamber. In a processing apparatus configured to allow flow to flow toward a side entrance, a housing is disposed on the entrance side so as to cover the entrance of the processing chamber, and a plurality of casings are disposed within the housing in the axial direction of the processing chamber. Each gas shower room has a gas introduction part on one side that blows out gas to prevent outside air from being entrained, and an exhaust part on the other side that can freely exhaust the gas. The device is equipped with an outside air entrainment prevention device that is provided with an opening as a passage for taking the workpiece in and out of the processing chamber, and the opening ( By almost eliminating the temperature difference at the inlet (inlet part), it is possible to prevent outside air (atmospheric air) from being drawn into the processing chamber through the inside of the casing due to convection. It is possible to prevent the growth of an oxide film caused by the atmosphere, and it is also possible to reduce the flow rate of the outside air entrainment prevention gas flowing from one end of the processing chamber toward the inlet of the other end. In the case of a CVD apparatus, dust generation inside the processing chamber can be prevented.

〔Example〕

FIG. 1 shows an embodiment of the processing apparatus according to the present invention, particularly when it is applied to a thermal diffusion furnace.

Figure 2 is a simplified perspective view of the outside air entrainment prevention device shown in Figure 1;
3 is a sectional view taken along line mm in FIG. 1, FIG. 4 is an explanatory diagram of the operation of FIG. 1, and FIG. 5 is a front view showing an example of the opening/closing door.

The present invention will be explained below using FIGS. 1 to 5.

In FIG. 1, reference numeral 11 denotes a quartz reaction tube serving as a processing chamber for performing a predetermined reaction process, and this reaction tube 11 is heated to a predetermined temperature by a heater 12. During reaction processing, the wafers 31 are arranged in the reaction tube 11, the wafer mounting table 37 is placed in the reaction tube 11, a reaction gas (or reaction gas and Nz gas) is introduced from the gas introduction pipe 13, and the wafers are heated at a predetermined temperature. 31 is subjected to predetermined reaction treatments (for example, impurity diffusion treatment, oxide film formation treatment, etc.).

At all times (except during reaction processing) through the gas introduction pipe 13, at least when loading and unloading wafers, Nz gas is introduced as a gas for preventing entrainment of outside air and flows toward the inlet I4 to prevent entrainment of outside air.

Furthermore, an outside air entrainment prevention device 15 according to the present invention is disposed on the inlet 14 side of the reaction tube 110. This outside air entrainment prevention device 15 is constructed as follows.

That is, a casing 16 made of stainless steel, for example, is fitted onto the outer circumferential wall of the reaction tube 11 on the inlet 14 side.

That is, as shown in FIG. 2, the outer circumferential wall of the reaction tube 11 is fitted into an opening 18 provided in the center of one wall 17 of the housing 16. This housing 16 is partitioned into a plurality of gas shower rooms 19 to 21, here three, by partition plates 22 and 23. Each of the gas shower chambers 19 to 21 is provided with gas shower devices 25 to 27 on one side, that is, on the upper wall 24 side, each serving as a gas introduction section for blowing out a gas for preventing entrainment of outside air into the room. These gas shower devices 25 to 27 penetrate the upper wall 24 and extend into the gas shower chambers 19 to 21 in a direction perpendicular to the axial direction of the reaction tube 11, as shown in FIG. An L-shaped gas introduction pipe 25b is provided with many small holes on the lower side of the parts 25a to 27a.
-27b, and a gas for preventing the entrainment of outside air which does not adversely affect the reaction process in the reaction tube 11 to each of the gas introduction pipes 25b to 27b. Note that the gas supply source is each gas introduction pipe 25b to 2.
They may be provided individually for each gas supply source 7b, or each gas introduction pipe may be connected to one gas supply source to supply the gas all at once from one gas supply source. Further, N2 gas is blown out downward from the small holes of the gas introduction pipes 25b to 27b like a curtain.

In addition, in the center of the bottom wall of each gas shower room 19-2,
Exhaust pipes 28 to 30 are connected to each other, and these exhaust pipes 28 to 30 are connected in common and can be evacuated by one exhaust pump (not shown).

However, when loading and unloading the wafer 31 as shown in the figure,
Although the N2 gas shower devices 25 to 27 are being driven,
The drive of the exhaust pump is stopped and the N2 gas is exhausted to the outside through the opening 33 which is the inlet provided in the center of the wall 32 on the opposite side facing the wall 17 of the housing 16. This prevents outside air from being drawn into the housing 16.

Next, an opening 34.35 is bored in the center of the partition plate 22.23 to form a passage for taking in and out the wafer 31, which is a member to be processed. These openings 33
- 35 are provided in the axial direction of the reaction tube 11, and these holes are arranged on the quartz fork 36, the wafer mounting table 37 held by the tip 36a of the quartz fork 36, and the wafer mounting table 37. The holes are formed to a size large enough to allow a large number of wafers 31 to pass through. The shape of the tip 36a of the quartz fork 36 is as shown in FIG.
A wafer mounting table 37 is held by the tip portion 36a. This wafer mounting table 37 has legs 37b attached to each of the four corners of a rectangular frame member 37a.

In the diffusion furnace configured in this way, during reaction treatment,
A reaction gas (or reaction gas and N2 gas) is introduced into the reaction tube 11 from the gas introduction pipe 13, and the wafer 31 on the wafer mounting table 37 placed inside the reaction tube 11 is heated at a specified temperature. A reaction process is performed, and at this time, the gas shower devices 25 to 27 and the exhaust pump are driven to blow out Nt gas from the gas introduction pipes 25b to 27b, and also to each gas shower chamber 19 through each exhaust pipe 28 to 30.
Exhaust the gas in ~21.

In this case, hot air such as unreacted reaction gas blows out from the inlet 14 side of the reaction tube 11 into the casing 16 of the outside air entrainment prevention device 15 . Then, convection occurs due to the hot air in the first stage gas shower room 19, and a part of the hot air goes out to the next gas shower room 20, and a part of it goes out to the next gas shower room 21. However, while the hot air goes out to this gas shower room 21, it is cooled by convection with the N2 gas from the gas shower room 25, 26, and near the opening 33 of the last gas shower room 21 where it comes in contact with the outside air. Since there is almost no difference in temperature between the inside and outside, no convection occurs due to heat, and therefore, the N2 gas from the gas shower device flows like a curtain, even without installing a door in the opening 33 to isolate it from the outside. Entrainment (intrusion) of outside air can be effectively prevented. Even if outside air is drawn in, it will be immediately exhausted through the exhaust vibrator 30, so there will be no problem.In addition, during the reaction process, an opening/closing door (not shown) is provided in the opening 33 in advance. If the opening/closing door is closed, the intrusion of outside air is completely prevented.Next, when loading and unloading the wafer 31 as a member to be processed as shown in Figure 1 of the table (during non-reactive processing), the opening Even if an opening/closing door is provided at the door 33, it will be opened, which poses a problem of outside air being drawn in. However, in the present invention, outside air is prevented from being drawn in as follows.

That is, N2 gas as a gas for expelling outside air is supplied into the housing 16 from the gas introduction pipe 13 of the reaction tube 11 in the form of hot air (for example, after a reaction process). At this time, the outside air entrainment prevention device 15 stops driving the exhaust pump and leaves the gas shower devices 25 to 27 driven. Therefore, independent N2 flows (convection) occur in the gas shower chambers 19 and 20, and by the time a part of the Nt hot air enters the gas shower chamber 21 in the third stage of the platform, it is cooled by convection and connected to the outside. The temperature difference will almost disappear. Therefore, the gas inside the casing 16 exits through the gap around the quartz fork 36 in the opening 33, but the entrainment of outside air due to convection (
(intrusion) does not occur. Note that the exhaust pump may be driven, but as shown in Figure 1, outside air may be drawn into the housing 16 when the quartz fork 36 is moved in and out, so it is recommended to stop driving the exhaust pump or drive it slightly. Good. Here, we will take as an example a situation in which the quartz fork 36 is moved together with the wafer mounting table 37 on which the wafer 31 shown in FIG. The operation will be explained using FIG. 4 as follows. That is, in the first stage gas shower chamber 19, convection of N2 gas occurs between the N2 gas from the gas shower device 25 and the N2 gas generated by the hot air, as shown by the arrow, and the hot air of N and gas is cooled.

Part of the N2 gas moves to the second stage gas shower chamber 20, where the hot Nz gas air is further cooled by convection as shown by the arrow, and part of it is transferred to the third and final stage gas. By the time it enters the shower room 21, it has been cooled down to almost the same temperature as the outside air, so in the gas shower room 21, the Nz gas from the gas shower device 27 and the Nz gas enter from the front stage. There is no convection due to heat between the N2 gas and the gas shower device 2.
The N2 gas from 1 flows effectively like a curtain,
The internal N2 gas is removed from the opening 33 by stopping the exhaust pump.
It is possible to blow out more air and prevent outside air from entering.

The above description is based on the situation where the quartz fork 36 is about to be removed from the housing 16.
Even in the case where the wafer mounting table 37 on which the wafers 1 and 1
The same explanation applies to the case where the quartz fork 36 is being inserted or removed in the direction of the arrow 38 or 39 as shown in the figure. However, when the latter quartz fork 36 is being inserted or removed in the direction of arrows 38 or 39, in order to close the gap around the quartz fork 36 in the opening 33, it is necessary to prevent the movement of the quartz fork 36 in the directions of arrows 38 and 39. If an opening/closing door 40 is attached to the wall 32 that inserts the quartz fork 36 from the top and bottom or from the left and right to prevent the quartz fork 36 from being damaged, the entrainment of outside air when the quartz fork 36 is taken in and out can be made even more complete. . FIG. 5 shows a case where an opening/closing door 40 is used in which a quartz fork 36 is sandwiched between two members 40a and 40b (arrows shown in the figure indicate opening/closing directions). In this case, if an opening/closing door that can be completely closed during reaction treatment is provided as described above, a double door may be used.

When loading and unloading the wafers 31, which are the members to be processed, as described above, that is, when loading and unloading the wafer mounting table 37 on which the wafers 31 are arranged using the quartz forks 36, from the housing 16,
Inside the outside air entrainment prevention device 15, N2 from the reaction tube 11
Each gas shower room 19.20 uses independent Nz gas hot air and N2 gas from the gas shower equipment 25.26.
Gas flow (convection) is created, and the last stage gas shower room 2
When a part of the hot air moves to 1, it has already been cooled, so no convection due to heat occurs, and there is almost no temperature difference between the inside and outside near the opening 33 where it comes in contact with the outside air, so the outside air due to convection does not occur. There is no entrainment, so the reaction tube 11
Prevents outside air from getting inside. Koreruyori reaction tube 1
Even if the wafers 31 are placed in the reaction tube 11 (for example, if the wafer mounting table 37 on which the wafers 31 are arranged is placed in the reaction tube 11 and only the quartz fork 36 is taken out), an unintended oxide film may be formed due to the atmosphere. There's no such thing as growing up. Furthermore, by providing the outside air entrainment prevention device 15, the effect of preventing outside air entrainment can be sufficiently achieved even if the flow rate of N2 gas is reduced to prevent outside air entrainment (exhaust air) from the gas introduction vibrator 13 at the back of the furnace.

〔effect〕

(1) In the outside air entrainment prevention device, it is possible to almost eliminate the temperature difference at the point in contact with the external air (outside air) of the passage for taking in and out the workpiece, so that the outside air passes through the outside air entrainment prevention device. It can prevent it from getting caught inside the processing chamber.

(2) According to (1) above, it is possible to prevent the growth of an oxide film due to the atmosphere on the member to be processed placed in the processing chamber.

(3) In the outside air entrainment prevention device, it is possible to almost eliminate the temperature difference at the part of the passage for taking the workpiece in and out that comes into contact with the outside air, so at least when the workpiece is taken in and out of the process chamber, one end of the process chamber It is possible to reduce the flow rate of the gas for preventing outside air entrainment (expelling outside air) that flows from the side toward the inlet on the other end side.

(4) From (3) above, especially in the case of horizontal CVD feeding,
Dust generation inside the processing chamber as in the conventional case can be prevented.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the above Examples and can be modified in various ways without departing from the gist thereof. Nor. For example, although N2 gas is used as the gas for preventing outside air from being drawn in (expelling outside air), other gases such as inert gases that do not adversely affect the reaction process may also be used.

In addition, although a cooling device using a refrigerant such as water is not provided in the outside air entrainment prevention device 15,
A cooling device may be provided to help cool the gas inside the housing 16 and bring it to the same temperature as the outside air. In this case, for example, each gas shower compartment 19 to 21 in the housing 16 of the outside air entrainment prevention device 15, particularly the gas shower compartment 19.2.
A device that cools the internal gas by arranging pipes that flow a refrigerant such as water over the entire inner wall surface of the 0 is considered.
When the temperature inside the reaction tube 11 is high, the inlet 1 of the reaction tube 11
This is effective for quickly cooling the hot air coming out from the 4 side into the housing 16.

[Application field]

In the above description, the invention made by the present inventor has been mainly applied to a diffusion furnace, which is the background field of application, but the invention is not limited thereto, and can be applied to, for example, a horizontal CVD apparatus. In the case of this horizontal CVD apparatus, when a member to be processed (for example, a semiconductor wafer) is taken in and out of a reaction tube serving as a processing chamber,
In order to prevent outside air from being drawn in when the inlet cover is opened, a gas to prevent outside air from being drawn in (for expelling outside air), such as Nt gas, is introduced from the back of the furnace (exhaust side) and flows toward the inlet. By installing the above-mentioned outside air entrainment prevention device, the same effects as described above can be achieved, and the flow rate of N2 gas, which is used as a gas for preventing outside air entrainment (expelling outside air) from the back of the furnace (exhaust side), can be further reduced. This makes it possible to prevent dust generation inside the reaction tube as in the conventional method. The present invention performs a predetermined reaction process on a member to be processed in a processing chamber, and at least directs a gas for drawing in outside air (expelling outside air) from one end of the processing chamber toward an inlet at the other end when the member to be processed is taken in and taken out. It can be applied at least to a processing device in which the flow is carried out in one direction.

[Brief explanation of the drawing]

Fig. 1 is a simplified sectional view showing an embodiment of the processing device according to the present invention, Fig. 2 is a simplified perspective view of the outside air entrainment prevention device shown in Fig. 1, and Fig. 3 is a sectional view taken along line m-nr in Fig. 1. , FIG. 4 is an explanatory diagram of the operation of FIG. 1, FIG. 5 is a front view showing an example of a case where an opening/closing door is provided in the opening 33 of the housing 16 of FIG. 1, and FIGS. 6 and 7 are FIG. 3 is a simplified cross-sectional view showing each side of a conventional diffusion furnace equipped with an outside air entrainment prevention device. DESCRIPTION OF SYMBOLS 11... Reaction tube, 12... Heater, 13... Gas introduction pipe, 14... Inlet, 15... Outside air entrainment prevention device, 16... Housing, 19-21... Gas Shower room, 24... Earthen wall, 25-27... Gas shower device, 25b-27b... Gas introduction pipe, 28-
30...Exhaust pipe, 31...Wafer, 33-35
...Opening portion, 36...Quartz fork, 37...Wafer mounting table, 40...Opening/closing door. Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A predetermined reaction process is performed on the member to be processed in the processing chamber, and at least when the member to be processed is taken in and taken out, a gas for preventing the entrainment of outside air is supplied from one end of the processing chamber to the other end of the processing chamber. In a processing apparatus configured to flow toward an entrance on an end side, a passageway disposed on the entrance side so as to cover the entrance of the processing chamber and for taking the member to be processed into and out of the processing chamber. has at least a casing provided with a casing, a gas introduction part that allows the gas to flow into the casing, and an exhaust part that can exhaust the gas inside the casing, and the temperature of the part of the passage in contact with the outside air. A processing apparatus characterized in that an outside air entrainment prevention device that almost eliminates the difference is provided at the entrance of the processing chamber. 2. The outside air entrainment prevention device is configured by partitioning a housing disposed on the entrance side of the processing chamber into a plurality of gas shower chambers in the axial direction of the processing chamber, and each gas shower chamber includes:
It has a gas introduction part that blows out gas to prevent outside air from being entrained on one side, and an exhaust part that can freely exhaust gas on the other side.
2. The processing apparatus according to claim 1, wherein said gas shower chamber is provided with an opening as a passage for taking said workpiece into and out of said processing chamber. 3. The processing device according to claim 1 or 2, wherein the outside air entrainment prevention device includes a cooling device for cooling the gas inside the housing. 4. Claim 1, wherein the outside air entrainment prevention device is provided with a door that can be opened and closed at an entrance into the housing in a passage for taking the workpiece into and out of the processing chamber. 3. The processing device according to any one of items 3 to 3. 5. According to any one of claims 1 to 4, in which a gas that does not adversely affect the reaction process in the processing chamber, such as N_2 gas or an inert gas, is used as the gas for preventing entrainment of outside air. Processing equipment as described.