JP2559403B2 - Vertical processing apparatus and processing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a technique particularly effective when applied to a treatment in which a treatment fluid causes a chemical reaction in an object to be treated in a heating environment. Wafer (hereinafter,
It can be used for a diffusion process or an anneal process.

[Conventional technology]

As an example of a vertical structure processing apparatus used for processing wafers, the Industrial Research Institute Co., Ltd., issued November 29, 1984, "Electronic Materials 1984 Separate Volume, VLSI Manufacturing and Testing Equipment Guidebook", P60 This document describes various advantages of a processing apparatus having a vertically arranged reaction tube, that is, a so-called vertical type processing apparatus, as compared with a horizontal type processing apparatus.

The present inventor has examined measures against heat loss in the processing apparatus having the vertical structure. The following is not a publicly known technique, but is a technique examined by the present inventor, and its outline is as follows.

For example, taking a diffusion device as an example, after a predetermined heat treatment is completed inside the reaction tube, the furnace opening of the reaction tube is opened and the wafer, which is the object to be processed, is taken out together with the jig. During preparation for processing the wafer, the furnace opening remains open.

[Problems to be solved by the invention]

However, as described above, with the furnace opening opened,
For example, if it is left for several minutes, the temperature of the processing area inside the reaction tube drops rapidly, and when performing subsequent wafer processing,
It was found by the present inventor that a recovery time for raising the temperature condition of the processing region to a constant temperature again is required for a long time.

Also, in the special processing process that can not take enough time from the previous processing to the next processing,
It may be necessary to start the process even if the temperature is lower than the specified value without having a temperature recovery time.In such a case, the time during which the furnace opening was opened, or The temperature condition of the processing area at the start of processing is not always constant depending on the ambient temperature state. Nevertheless, if the processing is started for the above reasons, the temperature conditions will vary depending on the processing, and the stability of the product cannot be ensured.

Furthermore, the present inventor has found that if the state in which the furnace port is opened continues for a long time, foreign matter may enter the inside of the reaction tube and induce subsequent processing failure.

The present invention has been made in view of the above problems, and an object thereof is to provide a technique capable of improving work efficiency and reliability in heat treatment.

The above and other objects and novel features of the present invention are as follows.
It will be apparent from the description of this specification and the accompanying drawings.

[Means for solving problems]

The outline of a typical invention among the inventions disclosed in the present application will be briefly described as follows.

That is, a shut-off lid is attached to the inside of a vertically-placed reaction tube, and the shut-off lid is locked by drop-out prevention means provided inside the reaction tube at the lower part of the processing area when the object to be treated is taken in and out. In addition to sealing the processing area,
The structure is such that when the object to be processed is inserted into the processing area, it is urged by the upper part of the jig that holds the object to be processed and pushed up above the processing area.

[Action]

According to the above-mentioned means, when the object to be processed is taken in and out, the processing area is sealed by the blocking lid, so that heat dissipation in the processing area can be suppressed and the recovery time to the specified temperature in the processing area is shortened. At the same time, it is possible to prevent variations in the processing start temperature due to the influence of heat dissipation, and it is possible to perform highly reliable processing. Further, it is possible to prevent contamination of the processing area due to mixing of foreign matter from the outside.

[Embodiment 1] FIGS. 1A and 1B are explanatory diagrams sequentially showing processing steps using a diffusion device according to an embodiment of the present invention.

This embodiment is applied to a so-called diffusion device 1 which forms a predetermined diffusion layer of P-type or N-type on the surface of an object wafer 2 to be processed, and is installed in a vertically long shape with its upper end It is closed in a dome shape, and the lower end of the wafer 2 is a lead-out port
It has a reaction tube 3 formed as 3a. The reaction tube 3
The inside of the chamber is configured as a treatment zone A, and the treatment fluid supply pipe 4 is guided to the treatment zone A from the outside of the reaction pipe 3. From the opening tip of the treatment fluid supply pipe 4, nitrogen as a treatment fluid is introduced. The gas 5 is supplied to the processing liquid A. On the other hand, an exhaust pipe 6 is connected to the processing area A below the reaction tube 3 so that the inside of the processing area A is exhausted as necessary.

Here, FIG. 1 (a) shows a processing state by the present apparatus 1. In this processing state, the processing area A is
A plurality of wafers 2 are held by a jig 7 at predetermined intervals so as to be parallel to the width cross-sectional direction of the reaction tube 3. The jig 7 is configured integrally with a sealing lid 8 attached to the outlet 3a of the reaction tube 3,
Therefore, the wafer 2 is set to the optimum processing position in the processing area A when the sealing lid 8 is attached to the lead-out entrance 3a.

In FIG. 1 (a), a shielding lid 10 made of quartz glass is placed on the upper surface of the jig 7. This blocking lid 10
For example, it is formed by connecting a plurality of disc members 10a in parallel while maintaining a constant interval, and the space between the disc members 10a facing each other functions as a buffer space, and the blocking lid 10 The structure is such that the heat flow in the vertical direction is suppressed at the boundary. Therefore, in the state of FIG. 1 (a), the shutoff lid 10 prevents the heat from being dissipated upward in the processing area A, and the thermal efficiency at the time of processing is improved.

A projecting portion 11 is provided inwardly on the lower inside of the reaction tube, that is, on the inner surface of the outlet 3a, and the inner diameter of the reaction tube 3 in this portion is at least smaller than the diameter of the blocking lid 10. It has a structure. Therefore, the reaction tube 3
When the sealing lid 10 is removed from the jig and the jig 7 is lowered outside the reaction tube 3, the blocking lid 10 is locked to the protrusion 11 as shown in FIG. 1 (b). It stays at the inner lower end of the reaction tube 3 and keeps the treatment area A isolated from the outside air.

A heater 12 as a heating means is provided around the side portion of the reaction tube 3 to heat the treatment area A to a predetermined temperature condition, for example, a temperature of about 1000 ° C. which is a general diffusion temperature condition. It is made possible.

Further, the periphery of the heater 12 and the upper end of the device 1 are
For example, it is covered with a heat insulating body 13 made of ceramic wool or the like to prevent heat dissipation to the outside of the device.

 Next, the operation of this embodiment will be described.

First, a predetermined number of wafers 2 are held by the jig 7, and the sealing lid 8 is attached to the outlet 3a of the reaction tube 3. At this time, the shutoff lid 10 is treated by the upper surface of the jig 7 in the processing area A.
Is pushed to the upper side (Fig. 1 (a)).

In this state, an inert gas such as nitrogen gas 5 as a carrier is supplied into the processing area A from the processing fluid supply pipe 4, and the processing area A is filled with the inert atmosphere. on the other hand,
When the processing area A is heated to a certain temperature by heating the heater 12, a diffusion reaction of impurities such as phosphorus (P) or boron (B) added in advance on the surface of the wafer 2 is started, A predetermined P-type layer or N-type layer is formed in the surface region of 2.

In such a diffusion process, the jig 7 is used in this embodiment.
Since the heat dissipation to the upper side of the processing area A is effectively blocked by the action of the blocking lid 10 located on the upper surface of the wafer 2, the heating efficiency of the heater 12 for the wafer 2 can be kept high. In this way, when the reaction is continued for a certain period of time, for example, about 8 to 10 hours which is a general diffusion time and the processing is completed, the sealing lid 8 is removed and the jig 2 and the wafer 2 are removed.
Is dropped below the outside of the reaction tube 3 (FIG. 1 (b)).
At this time, the shutoff lid 10 placed on the upper surface of the jig is also lowered inside the reaction tube 3 together with the jig 7, but the shutoff lid 10 is formed by the protrusion 11 provided on the inner side surface of the outlet 3a. Reaction tube 3
It is locked at the inner lower end of the. In this way, when the wafer 2 is taken out of the reaction tube, the processing area A inside the reaction tube 3 is shut off from the outside air by the shutoff lid 10.
Therefore, heat dissipation from the processing area A is prevented, and the processing area A is maintained at a constant high temperature. Therefore, even when the wafer 2 for the subsequent processing is mounted on the jig 7 and inserted into the processing area A, the temperature recovery time to the specified temperature condition is extremely short and the subsequent processing is efficient. Can be done.

Further, since heat dissipation from the processing area A can be prevented when the wafer 2 is taken in and out, the temperature in the processing area A can be kept substantially constant without being affected by outside air or the like. Therefore, the subsequent processing start conditions can be made uniform,
In particular, the stability of the process can be achieved in a short-time process or the like in which the waiting time from the previous process to the subsequent process cannot be sufficiently taken.

From this, according to this embodiment, the following effects can be obtained.

(1). At the time of loading / unloading the wafer 2, the outlet 3a of the reaction tube 3 is closed by the shutoff lid 10, so that heat dissipation can be prevented, which suppresses the temperature drop in the processing area A and regulates the subsequent processing. The temperature recovery time can be shortened.

(2). According to the above (1), efficient wafer processing becomes possible and the manufacturing efficiency of the semiconductor device can be improved.

(3). According to the above (1), the temperature decrease in the processing area A can be prevented and the subsequent processing start temperature can be made uniform, so that the stability of the processing in the wafer processing can be achieved.

(4). When the wafer 2 is taken in and out, the lead-in port 3a is closed, so that foreign matter can be prevented from entering the processing area A, and processing defects of the wafer 2 due to contamination of the processing area A can be prevented.

[Embodiment 2] FIG. 2 is an explanatory view showing a hydrogen annealing apparatus which is another embodiment of the present invention.

In this embodiment, the present invention is applied to a hydrogen annealing device 21, and like the first embodiment, a reaction tube 22 having an upper end closed in a dome shape and a lower end opened as an outlet 22a is provided. are doing.

Inside the reaction tube 22, the upper processing liquid A is formed,
It has a structure in which an adiabatic zone B is formed below, and processing fluid supply pipes 4a and 4b are connected to the zones A and B from the outside of the reaction tube 22, respectively, and hydrogen is supplied to the zones A and B. A mixed gas 23a with nitrogen or a nitrogen gas 23b is supplied.

The wafer 2 is held by a jig 24 so as to be parallel to the width cross-sectional direction of the reaction tube 22, and a lower portion of the jig 24 is penetrated by a sealing lid 25 attached to the outlet 22a. Further, a support rod 24a extending further downward is connected. The support rod 24a is movable in the tube axis direction by an operation from below and the wafer 2 is moved in the reaction tube 22 together with the jig 24 accordingly.

The shutoff lid 10 of the present embodiment has the same structure as that of the first embodiment, and the protrusion 11 provided at the lower part of the processing area A prevents the processing area A from falling off to the heat insulating area B. It is in the state of being An exhaust pipe 26 is provided so as to project from the lower outer surface of the reaction tube 22, and among the mixed gas 23a supplied to the inside of the reaction tube 22, a combustible material such as hydrogen gas that has not contributed to the treatment is combustible. The gas component is burned at the tip of the discharge pipe 26.

A heater 12 as a heating means is provided outside the side of the portion of the reaction tube 22 corresponding to the treatment liquid A so as to keep the treatment area A at a predetermined temperature condition, for example, about several hundreds of degrees Celsius. In addition, the periphery and the upper part of the reaction tube 22 other than this are covered with a heat insulator 13 made of, for example, ceramic wool or the like to prevent heat dissipation to the outside.

Next, the operation of this embodiment will be described below.

First, while a predetermined number of wafers 2 are held by the jig 24, they are inserted into the reaction tube 22 through the outlet 22a by operating the support rod 24a, and further transferred to the position shown by the chain double-dashed line in FIG. To be Along with this, the blocking lid 10 located at the lower portion of the processing area A is pushed upward of the processing area A by the upward movement of the jig 24.

Next, the sealing lid 25 is attached to the outlet 22a, and the reaction tube 22
When the inside of the reactor is sealed, the mixed gas 23a of hydrogen gas and nitrogen gas is supplied from the treatment fluid supply pipe 4a to the inside of the reaction pipe 22, and the treatment liquid A is filled with these fluid atmospheres. Becomes At this time, the H groups in the hydrogen gas are successively bonded to the mismatching connectors existing at the interface between the silicon (Si) and the silicon oxide film (SiO ₂ ) on the surface of the wafer 2 and the electrical property as a semiconductor element is increased. A chemical treatment is performed to stabilize the properties. During such processing, the processing area A is cut off by the blocking action of the blocking lid 10 placed on the upper surface of the jig 24.
Dissipation of heat upwards is effectively prevented.

When the annealing treatment for the prescribed time is completed, the reaction tube
The support rod 24a is operated again from below the outside of the jig 22, and the jig 24
At the same time, the wafer 2 is lowered from the processing area A to the heat insulating area B. At this time, the blocking lid 10 placed on the upper surface of the jig 24
Also descends in the processing area A together with the jig 24, but the processing area A
Even if the jig 24 is further lowered by the protrusion 11 at the lower part of the processing area A, the shutoff lid 10 is locked to the lower end of the processing area A, so that the processing area A and the heat insulating area B can act as the shutoff lid 10. It becomes a state of being separated by boundaries. Therefore, at this time, the blocking lid 10 prevents the fluid from flowing out from the processing area A to the heat insulating area B. In addition, the heat blocking action of the blocking lid 10 effectively prevents the temperature drop in the processing area A.

In this way, when the wafer 2 is positioned in the heat insulating area B, the supply of the nitrogen gas 23b from the fluid supply pipe 4b is started this time, and the heat insulating area B becomes an inert atmosphere. Further, since the heat insulating area B is temperature-controlled so as to be an intermediate temperature between the processing area A and the temperature outside the apparatus (normal temperature), the wafer 2 located in the heat insulating area B is gradually cooled. Since the wafer 2 is gradually cooled in this manner, the bonding state between the mismatched bond and the H group due to the annealing process is stabilized.

Next, the sealing lid 25 of the outlet 22a is opened, and the wafer 2 held by the jig 24 is taken out of the tube. At this time,
The heat insulating area B is exposed to the outside air, but this heat insulating area B
Is filled with the inert atmosphere as described above and is separated from the processing area A by the heat insulating lid 10, so that the wafer 2 with high safety can be taken out.

As described above, in the hydrogen annealing apparatus 1 according to the present embodiment, after the annealing treatment in the processing area A, the wafer 2 is positioned in the heat insulating area B thermally shielded by the heat insulating lid 10, and in the heat insulating area B, Since the wafer 2 is gradually cooled and then taken out, defective processing of the wafer 2 due to a rapid temperature change can be prevented.

Further, at this time, the processing area A is prevented from inflowing outside air and is maintained at a constant high temperature.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Nor. For example, the blocking lid 10 may have any structure as long as it has a heat blocking effect, such as a structure in which quartz wool is vacuum-sealed.

In the above description, the case where the invention made by the present inventor is mainly applied to a vertical structure diffusion device and a hydrogen annealing device, which are the fields of use thereof, has been described, but the present invention is not limited to this and, for example, an oxidation device. , CVD
(Chemical Vapor Deposition) device, and further can be used for an argon annealing device.

〔The invention's effect〕

The effect obtained by the representative one of the inventions disclosed in the present application will be briefly described as follows.

That is, the processing area inside the reaction tube is locked by the drop-out preventing means provided inside the reaction tube, and holds the object to be processed when the object is inserted into the processing area. By providing a blocking lid that is urged to the top of the jig and pushed up above the processing area, it is possible to prevent heat dissipation in the processing area when putting in and out the object to be processed, and shorten the recovery time to the specified temperature in the processing area. In addition, it is possible to make the subsequent processing start temperature uniform and improve processing efficiency and processing reliability.

[Brief description of drawings]

1 (a) and 1 (b) are explanatory views sequentially showing processing steps using a diffusion device according to an embodiment of the present invention, and FIG. 2 is an illustration showing a diffusion device according to another embodiment of the present invention. It is a figure. 1 ... Diffusion device, 2 ... Wafer (object to be processed), 3 ... Reaction tube, 3a ... Outlet port, 4,4a, 4b ... Processing fluid supply tube,
5 ... Nitrogen gas (processing fluid), 6 ... Exhaust pipe, 7 ... Jig, 8 ... Sealing lid, 10 ... Blocking lid, 10a ... Disc member, 1
1 …… Projection, 12 …… Heater, 13 …… Insulator, 21 ……
Hydrogen annealer, 22 ... Reaction tube, 22a ... Outlet port, 2
3a ... mixed gas, 23b ... nitrogen gas, 24 ... jig, 24a ...
… Support rod, 25… Sealing lid, 26… Discharge pipe, A… Treatment area, B… Insulation area.

Claims (4)

(57) [Claims] 1. A reaction tube which is vertically long and has a treatment zone inside, a heat insulation zone below the treatment zone, and a discharge inlet for a substance to be treated at the lower end, and heating means for heating the treatment zone. A sealing lid that closes the outlet, a jig that holds the object to be treated, and a movable heat-insulating lid that separates the treatment area and the heat-insulating area in the reaction tube. When the object to be processed is put in or taken out of the tube and when the jig is present in the heat insulating area in the reaction tube, a drop-out preventing means provided in the reaction tube is provided between the processing area and the heat insulating area. It is stopped to seal the processing area in the reaction tube, and when the jig is present in the processing area in the reaction tube, it is moved upward in the reaction tube by the jig. Vertical processing device. 2. The vertical processing apparatus according to claim 1, wherein the shut-off lid in the reaction tube is made of quartz glass. 3. The heating means is a heater, and a heat insulating body is provided outside the reaction tube corresponding to a heat insulating area excluding the lead-out port. Vertical processing device according to paragraph. 4. A step of placing an object to be processed on a jig, and a step of placing the jig on which the object to be processed is placed in the reaction tube from a lower end of a reaction tube whose upper end is closed and whose lower end is opened. A step of inserting into the heat insulation zone, and by moving the jig upward, between the heat insulation zone in the reaction tube and the treatment zone above the heat insulation zone by the fall prevention means provided in the reaction tube. A step of moving the locked shut-off lid upward, a step of treating the object to be processed at a predetermined temperature in the processing area; a step of moving the jig downward to move the shut-off lid to the drop-off preventing means. And a step of taking out the jig from the lower end of the reaction tube.