JPH045820A - Vertical semiconductor manufacturing apparatus - Google Patents

Abstract

PURPOSE:To constitute various heat-treatment furnaces by using a simple single-tube structure by a method wherein a holder is placed on the upper part of a tube body, they are inserted into the uniform-heat length of a core tube to form an apparatus and a heat treatment is executed by using the apparatus. CONSTITUTION:A gas introduction tube which reaches the top from the lower part along the outer wall of a quartz core tube 1 is connected; a wind rectification sheet 2 is arranged at the upper part of the tube 1 in order to disperse an introduced gas. An electric furnace 13 surrounds the tube 1; a boat as a whole, a boat cradle 4 and the top of a quartz tube 5 are situated in its uniform-heat length. The gas enters from an introduction port 8; it is passed through the uniform-heat length part; it is spouted to the side of the boat from the sheet 2; it is discharged to the outside from a discharge port 7. At a handling operation, nitrogen as an inert gas is made to flow from the introduction port 8; a gas inside a system is replaced; water is passed through a pipe 10 which has been wound on a cylindrical skirt 9; the nitrogen gas is made to flow from an introduction port 15. A boat elevator system 12 is lowered; the quartz tube 5 is lowered. A skirt elevator system 11 is actuated at the time when the temperature of a wafer has been cooled to a prescribed temperature; the skirt 9 is lowered; a wafer boat 3 can be detached.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to the manufacturing of semiconductor devices, and in particular, to a large-diameter vertical device that enables various film formations and heat treatments such as diffusion in the manufacturing of semiconductor devices. The present invention relates to type semiconductor manufacturing equipment.

[Conventional technology]

In the manufacture of semiconductor devices, it is necessary to form various films, such as silicon oxide films, silicon nitride films,
Polysilicon, etc., is grown in a vapor phase. Furthermore, in order to form a semiconductor device, oxidation of the silicon substrate and diffusion treatment of impurities are essential.

Heat treatment furnaces are used to perform these heat treatments such as oxidation, diffusion, and vapor phase growth.

At present, hot wall type diffusion and CVD equipment is the mainstream for vapor phase growth and diffusion of the various films mentioned above, including silicon oxide films, and in the case of horizontal furnaces, horizontally arranged The wafers are placed upright in a quartz reaction tube to improve the number of wafers that can be processed at a time.

On the other hand, in the case of a vertical furnace, the reaction tube is placed upright, and the wafers are stacked horizontally and quartz ports are inserted into the reaction tube from below or above. Heat treatment is performed.

This vertical furnace is advantageous because it requires less floor space for installation than a horizontal furnace, and is being actively introduced.

Furthermore, it has been found that this vertical furnace is suitable for increasing the diameter of wafers. That is, when performing high-temperature oxidation or high-temperature well diffusion for CMO3 in a horizontal furnace, the central portion of the quartz reaction tube bends downward due to the high temperature. As the diameter increases, the weight of the port increases, which increases deflection and makes it impossible to maintain a uniform temperature distribution in the vertical direction within the reaction tube. Vertical furnaces do not have this problem due to the quality of the wood.

This vertical furnace, for both the diffusion furnace and the CVD equipment, has a basic structure in which a port carrying a wafer is taken in and out of the quartz reaction tube in the vertical electric furnace in the vertical direction. For the purpose of handling gas introduction and exhaust, if a double quartz tube is used and the port is inserted from the bottom, in a diffusion furnace, the gas introduction tube is connected to the top as piping from the bottom to the top of the internal quartz tube. The reactant gas is introduced from the lower end of the internal quartz tube into the internal quartz tube and exhausted from the lower end of the internal quartz tube. The structure is designed to exhaust air.

Further, as a specific structure of this vertical furnace, a quartz heat-retaining tube is arranged below the internal quartz tube to keep the inside warm. Of course, the end of this heat-retaining tube is made flat from the viewpoint of space, and its position with respect to the electric furnace is designed so that it is installed in the auxiliary heater part outside the uniform heating length.

An example of this is JP-A-63-299116.

By the way, as a mass-produced CVD device, Anicon's CV
There is a D device. Although this equipment can accommodate two wafer ports, it is equipped with a heater around the central exhaust pipe to supply heat from the bottom of the port. Since the heat is dissipated from the wafer all at once, the air current is rolled up, and the adhesion of dust to the wafer is unavoidable.

[Problem that the invention seeks to solve]

Although vertical furnaces have many advantages, the height of commercially available furnaces is up to 3 meters, which makes them inefficient for processing a smaller number of wafers, and also makes handling such as furnace cleaning difficult. It's not easy either. In particular, it is not easy to clean a furnace with a double pipe structure.

Therefore, the present invention provides a vertical furnace that has a simpler furnace structure and is easier to handle, such as cleaning. The second object of the present invention is diffusion and heat treatment.

Based on the structure commonly used for vapor phase growth,
A vertical furnace having a structure that is easy to clean is provided.

A third object of the present invention is to provide a vertical furnace having a structure that allows the wafer port to be taken out without entraining the atmosphere at the opening of the furnace after the various heat treatments described above are completed.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a semiconductor wafer holder is placed on the top of a quartz cylinder having a spherical top, and these are placed on the top of the furnace core tube evenly. As a device inserted into the thermal chamber,
The vertical semiconductor manufacturing equipment is characterized by performing heat treatments such as oxidation, diffusion, and vapor phase growth.

According to the second feature of the present invention, the top of the heat-resistant cylinder having a spherical top is covered with a quartz cylinder surface having a spherical top, and a semiconductor is provided on the top of the spherical top of the quartz cylinder. Oxidation and diffusion are carried out as a device in which a wafer holder is mounted and these are inserted within the soaking length of the furnace core tube.

The present invention is a vertical semiconductor manufacturing apparatus characterized by performing heat treatment such as vapor phase growth.

According to a third feature of the present invention, a plasma cleaning electrode is installed on the outer wall of the furnace core tube to facilitate cleaning of the vertical furnace having a double-tube structure.

The next feature of the present invention is that when constructing a vertical furnace for performing CVD, the heat-resistant cylindrical body is not completely inserted into the soaking length of the furnace core tube. Place a reflective plate inside. Due to this feature, a reflector such as a quartz plate or silicon carbide is not placed within the soaking length heated to a high temperature.

Silicon carbide turns black, loses its transparency, and loses its ability to block heat at temperatures above 700°C, so the silicon carbide reflector is placed at a location where the temperature is below the above temperature.

[Function] In view of the fact that conventional vertical furnaces have long vertical dimensions and are not easy to clean, the present invention provides a cylindrical structure that can accommodate large wafers. As a result of repeated studies in order to develop a device that can be used in a single-tube structure and that can be used for both diffusion and heat treatment vapor phase growth, we came up with the concept of a vertical furnace based on a furnace core tube with a single-tube structure. Ta.

That is, in a preferred embodiment of the present invention, a furnace core tube is used in which an introduction tube is installed on the tube wall of a single layer tube so that gas can be introduced from the top of the layer tube, and a furnace core tube is installed in the soaking length portion of the furnace core tube. The boat is supported on top of a quartz tube with a spherical top that has excellent resistance to deformation even when placed on the boat. The spherical top has high resistance to high-temperature treatment, and its spherical shape prevents deformation even at high temperatures that would normally cause deformation in a simple cylindrical shape.

In order to further maintain resistance to deformation, a cylinder made of a heat-resistant material with a spherical top, for example, a cylinder made of silicon carbide 2 or carbon, which has good heat absorption, is placed in contact with the inside of the spherical top of the quartz tube. It is better to install

In order to enable plasma self-cleaning, an electrode wire having a structure capable of applying high frequency waves may be installed on the outer wall of the −-shaped furnace core tube.

Although this electrode wire has a structure integrated with the electric furnace, it allows the --type furnace core tube to be attached and detached for cleaning the --type furnace core tube.

When constructing a vertical furnace for performing CVD, a reflector plate is arranged inside the heat-resistant cylinder without completely inserting the heat-resistant cylinder into the soaking length of the furnace core tube. Due to this feature, a reflective plate such as a quartz plate or silicon carbide is placed at a position outside the soaking length where it is heated to an intermediate temperature. Silicon carbide turns black, loses its transparency, and loses its ability to block heat at temperatures above 700°C, so the silicon carbide reflector is placed at a location where the temperature is below the above temperature.

In any of the heat treatment furnaces, there is no need to install an attached heater like in Anicon at the lower position of the -type furnace core tube, and therefore, when taking out the wafer boat,
No entrainment of air current occurs.

In order to increase the number of wafers to be processed, an arbitrary number of vertical furnaces of the present invention can be installed in rows, and a common loading mechanism can be installed for the rows of furnaces. It is possible to take boats in and out.

〔Example〕

Referring to FIG. 1, a vertical semiconductor manufacturing apparatus according to an embodiment of the present invention that can be used as a diffusion furnace and a heat treatment furnace will be described.

Fig. 1 is a sectional view showing the configuration of a vertical furnace according to an embodiment of the present invention, where ■ is a quartz furnace core tube, and a gas introduction tube running along the outer wall from the bottom to the top is glued. There is. In order to disperse the introduced gas, a baffle plate 2 is placed above the furnace core tube l, and below it is a two-stage boat, which is placed on a boat pedestal 4. It is something that

As shown in the figure, this boat pedestal 4 is firmly attached to the top spherical part of the quartz tube 5, and inside the quartz tube 5, there are
For reinforcement, a reinforcing core tube 6 made of, for example, silicon carbide, which has higher heat resistance than quartz, is in contact at its spherical top. In this embodiment, the electric furnace 13 surrounds the furnace core tube 1, and the top of the boat pedestal 4 and the quartz tube 5, together with the entire boat, are located within its soaking length. .

When 25 8-inch wafers 14 are placed on the boat 3, the optimum wafer spacing requires a length of 25 cm, which is approximately equal to the wafer diameter. Therefore, the diameter of the furnace core tube may be about 35 cm. Of course, these boats may be arranged in two rows at the front and rear of the figure.

The wafers placed on this boat 3 can be made without a dummy and are suitable for mass production.

The gas enters through the gas inlet 8, passes through the soaking length section, is ejected from the air conditioning vi, 2 to the boat side, and is discharged to the outside from the discharge lower.

The solid line position shown in the figure indicates the installed state of the boat, and the dotted line indicates the lowest position of the boat.

To explain how to handle the device of this embodiment, at the solid line position shown in the figure, when the flanges of the quartz tube 5 are in contact with each other in an airtight state, and when the diffusion or heat treatment is completed, inert gas is supplied from the gas inlet 8. Flow nitrogen to replace the gas in the system.

On the other hand, water was passed through a water-cooled vibrator 10 wrapped around an aluminum cylindrical skirt 9, and the same (nitrogen gas) was passed through an inlet 15.

In this state, the boat elevating system 12 is lowered to the position shown, and the quartz tube 5 is lowered to the dotted line position. All nitrogen is allowed to flow to prevent unnecessary oxidation of the wafer 14. For example, 50
When the wafer temperature has cooled down to a predetermined temperature below 0''C, the skirt lifting system 11 is activated and the skirt 9
is lowered to the dotted line position, and the wafer boat 3 can be removed. The boat 3 is lifted by a robot hand, for example, to enable attachment of the next wafer port.

In this way, blowing up of hot air in the anime can be avoided.

The second part is a diagram showing the shape of the air conditioning board, (a) shows the slit shape, (b) shows the mensch shape, (C) and (d)
) shows a top view and a cross-sectional view showing the louver shape. These are examples; other structures are possible.

FIG. 3 is a sectional view showing the configuration of a vertical CVD furnace according to a second embodiment of the present invention. In order to provide commonality as devices, the furnace core tube and the quartz tube 5 have the same configuration and have similar structures.

The difference from FIG. 1 is, first, that a lower air baffle plate 16 is provided to uniformly supply the air to the quartz tube 5. The lower wind regulating plate 16 may be the same as the upper wind regulating plate 2. The second difference is that although CVD furnaces originally process at relatively low temperatures, the temperature at which silicon carbide changes color, that is,
Several reflection plates 17 made of silicon carbide are arranged at a temperature position that is maintained at a temperature lower than 00°C.

Since the upper baffle plate 2 is located at the soaking length position, even if the reaction gas passes through, a product with strong adhesion is formed, so that powder does not fall onto the wafers on the boat.

Since the attachment and detachment of the wafer port can be carried out in the same procedure as described in connection with FIG. 1, the explanation thereof will be omitted here.

FIG. 4 is a top view of an apparatus system in which four furnaces shown in FIG. 1 or 3 are arranged in a row to perform independent processing;
The figure shows a sectional view of its side.

At the left end of Figure 4, there is a shelf 18 for storing a plurality of unprocessed boats, and a shelf 19 for storing boats that have been processed.
The robot 20 takes out the boat from 8 and moves it to an arbitrary furnace 22 using the tronco 21. A loading robot 23 moves this boat to a relay machine 24 and then takes it into and out of the furnace 22. It goes without saying that the number of furnaces 22 installed varies depending on the number of wafers to be processed.

6, 7, and 8 show a cross-sectional view and a cross-sectional view of a CVD apparatus with plasma cleaning electrodes, and there are electrode wires in the quartz rod 25, and as shown in FIG. The arrangement is such that high frequency waves are applied between the two electrodes, which are connected in common, and when removing products that have adhered to the inside of the furnace using a CVD device, this high frequency wave is applied and the etching gas is introduced to create plasma. to achieve cleaning. A feature of this CVD apparatus is that the plasma electrode is integrated with the heater and does not pose any obstacle when removing the furnace core tube. Moreover, the electrode terminals are common at the lower end of the figure and can be easily connected and attached.

Although the above embodiments have been described using preferred examples, various modifications and changes can be made. That is, instead of the reinforcing core tube 6 made of silicon carbide shown in Fig. 1, it is possible to prepare a silicon carbide stand and provide a quartz protective plate (layer) on the flat surface thereof. It is also possible to use silicon carbide as a disk for receiving the disk 4, and to hold it in a quartz cylinder. In this case, as mentioned above, the heat shielding ability is lost below 700''C, so a radiation stopper is provided at the bottom.

Furthermore, it is possible to make changes to the cylindrical skirt 9 shown in Figure 1. For example, the skirt can be divided into upper and lower halves, with the upper side sliding on the outside of the lower side, and the boat 3 can be taken out in the slid state. may be possible.

The nitrogen gas inlet 15 may be provided under the skirt 9 to achieve nitrogen replacement inside.

〔Effect of the invention〕

As described above, in the present invention, a semiconductor wafer holder is placed on the top of a quartz cylinder with a spherical top, and these are inserted into the soaking length of the furnace core tube. Since the vertical semiconductor manufacturing apparatus is characterized in that it performs heat treatment such as growth, various heat treatment furnaces can be configured with a simple single tube structure. In addition, whereas conventional vertical furnaces have long vertical dimensions and are difficult to clean, it is possible to have a simple configuration that can accommodate large wafers, and it is extremely easy to add more furnaces. . More specifically, the spherical top has high resistance to high-temperature treatment, and its spherical shape prevents deformation even at high temperatures that would normally cause deformation in a simple cylindrical shape. In order to maintain resistance, a cylinder made of a heat-resistant material with a spherical top, such as silicon carbide or carbon, which has good heat absorption, is placed in contact with the inside of the spherical top of the quartz tube. There is.

Further, in order to enable plasma self-cleaning, an electrode wire having a structure capable of applying high frequency waves is installed on the outer wall of this --shaped furnace core tube. Since this electrode wire is constructed integrally with the electric furnace, it is possible to attach and detach the --type furnace core tube for cleaning the --type furnace core tube.

In any of the heat treatment furnaces, there is no need to install an attached heater like in Anicon as part of the electric furnace to achieve uniform heating length at the lower position of the −-type furnace core tube, and therefore, the wafer boat can be taken out. There is no entrainment of airflow during this process.

In order to increase the number of wafers to be processed, an arbitrary number of vertical furnaces of the present invention can be installed in rows, and a common loading mechanism can be installed for the rows of furnaces. It also has the advantage of allowing boats to be moved in and out.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a vertical furnace according to this embodiment of the present invention;
The figures are a top view and a side view showing the shape of the air baffle plate installed in the furnace shown in Fig. 1, Fig. 3 is a sectional view of a vertical furnace according to the second embodiment of the present invention, and Figs. FIG. 5 shows a top view and a side view of four furnaces arranged in a row, and FIGS. 6 to 8 show cross-sectional views of a vertical furnace equipped with a plasma cleaning electrode. In the figure, 1 is a furnace core tube, 2 is a baffle plate, 3 is a wafer boat,
4 is a boat cradle, 5 is a quartz tube, 6 is a reinforcing tube, 7 is an exhaust port, 8 is a gas inlet, 9 is a skirt, IO is a water cooling pipe,
11 is a skirt lifting system, 12 is a boat lifting system, 13 is a heater, 14 is a wafer, 15 is a nitrogen gas inlet, 16
17 is a wind regulating plate, 17 is a reflector, 18 and 19 are shelves, 20 is a storage robot, 21 is a trolley, 22 is a furnace, 23 is a loading robot, and 24 is a repeater. (C) Nonno
, Name of the invention Vertical semiconductor manufacturing device 3, Relationship with the case of the person making the amendment Patent applicant (zip code 214) Address 6-20-3 Nagao, Tama-ku, Yozaki City, Kanagawa Prefecture Name EFtinil Co., Ltd. Date of drafting Heisei 2
June 29, 1990 Full sending date: July 31, 1990 5. Drawings subject to amendment (Figures 1 to 8) 6. Contents of amendment As per the engraving and separate drawings of the drawings originally attached to the application ( No change in content) 13 items

Claims (1)

[Claims] A semiconductor wafer holder is placed on top of a quartz cylinder with a spherical top, and these are inserted into the soaking length of the furnace core tube to perform heat treatments such as oxidation, diffusion, and vapor phase growth. Features of vertical semiconductor manufacturing equipment.