JPH0878513A - Semiconductor wafer holder and semiconductor production system - Google Patents

Abstract

PURPOSE: To obtain a wafer holder being employed in the production of a semiconductor wafer in which wafers having different diameters can be processed simultaneously and collectively using a same boat. CONSTITUTION: A semiconductor wafer holder 11 being used in horizontal state is provided with a plurality of wafer stopping claws 15, depending on the diameter of a wafer to be mounted, at predetermined positions on the circular surface of predetermined diameter. The holder 11 and the claws 15 are made of a kind of material selected from a group of SiO2 , SiC, SiN and Si. A semiconductor wafer is mounted on the part of the holder partitioned by the claws 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer holder and a semiconductor device processed by a semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art Semiconductor integration is carried out by finely processing the surface area of a semiconductor wafer which is a substrate, and in the process, thin film formation, lithography, etching,
A large number of complicated processes such as impurity doping and metallization are repeated. In particular, an ultra-high density integrated circuit called a VLSI uses Si as a substrate semiconductor, but it is necessary to simultaneously process a large number of wafers having different diameters in common for one to several steps described above.
Each process is automated in order to avoid the influence of dust and to perform accurate submicron control, except for semiconductor wafers, equipment, raw material installation and preparation, and recovery and cleaning operations at the end. When forming an integrated circuit on the surface of a Si wafer, it is indispensable to form an oxide film which is a high-quality insulating film, impurity diffusion for forming an active region and element isolation, and CVD (chemical vapor deposition) for forming a functional region. This is an important step. In these steps, it is necessary to heat the Si wafer in the electric furnace.

Generally, an automated system for performing oxidation, diffusion and CVD processes can be represented by a block diagram as shown in FIG. A large number of Si wafers to be processed are filled in a predetermined position in the reaction chamber 1 which is normally shielded from the outside by a quartz glass. The jig which holds the Si wafer stored in the reaction chamber 1 is regularly filled with the Si wafer by the wafer transfer unit 5. After that, the inside of the reaction chamber 1 is once evacuated by the exhaust system 4, and then a clean replacement gas is sent from the gas system 3. Further, the heater 2 is operated and the temperature controller adjusts the S in the reaction chamber 1.
The i-wafer is heated to a predetermined constant temperature, and the reaction gas is introduced again from the gas system 3 to cause oxidation, diffusion or CVD. At the end, the inflow gas of the gas system 3 is switched and replaced with a non-reactive inert gas, the heater 2 is turned off and the processed Si wafer is taken out from the reaction chamber 1 after cooling. The gas system 3 is driven until just before the Si wafer is taken out of the reaction chamber 1, and at the same time, the exhaust system 4 is also driven. All of these series of steps are controlled by the controller 6 and are automated.

4 to 7 show the main parts of the oxidation, diffusion and CVD apparatus in the block diagram shown in FIG. 3, focusing on the Si wafer transfer system. There are vertical type and horizontal type in oxidation, diffusion, and CVD equipment, and Si and
Although the wafer mounting method is different, a vertical type apparatus has been widely used in recent years as a relatively compact apparatus capable of processing a large number of wafers. FIG. 4 shows the case of a vertical device.

The wafer transfer unit 5 includes a cassette 12 for storing a plurality of Si wafers and a wafer transfer mechanism 1.
It consists of three. In the cassette 12, a plurality of Si wafers processed in the previous step are placed on a horizontal holder and then stored. The wafer transfer mechanism 13 has a fork 14 and takes out the Si wafer together with the wafer holder from the cassette 12 that has been moved to the vicinity of the vertical apparatus with the Si wafer stored therein by the fork 14 for the vertical apparatus. Each Si wafer is placed at a predetermined position of.

The boat 8 is, as shown in the sketch in FIG.
Wafers 7 that are stacked horizontally by a plurality of columns 9
Protect. The reason why the wafer 7 is held by the support columns is to secure the flow path of the reaction gas, increase the reaction rate, and obtain a homogeneous treatment layer. Grooves 10 corresponding to the diameter of the wafer 7 are provided at the wafer 7 mounting positions of the columns 9 as shown in the sectional view of FIG. With respect to the plurality of Si wafers stored in the groove 10 from the cassette 12 by the fork 14 of the wafer transfer mechanism 13, the boat 8 was vertically lifted to the position indicated by the dotted line in FIG. 4 and fixed at a predetermined position in the reaction chamber 1. Then, the surface treatment is performed.

[0007]

By using the oxidation, diffusion, and CVD apparatus of the vertical type apparatus described above, an important process for forming a Si ultra-high-density integrated circuit can be performed automatically for a large number of Si wafers at one time. It becomes possible to do it. However, the integrated circuit is designed separately for each operation and performance of the electronic circuit used as the key device. On the other hand, in consideration of cost performance, the diameter of the Si wafer on which the integrated circuit is formed in the surface area does not always have to be the same size. But,
For efficient production, it may be necessary to simultaneously process Si wafers of different sizes in the same process such as oxidation, diffusion, or CVD.

At this time, the diameters of the boat 8 and the groove 10 shown in FIGS. 5 and 6 are the maximum diameter Si stored in the apparatus of FIG.
Designed to suit the wafer. Therefore, as shown in FIG. 7, the Si wafer 7 having a radius smaller than (D / 2−W) is represented by the diameter D of the boat 8 measured between the deepest portions of the groove 10 and the depth W of the groove 10. , Cannot be placed on the boat 8. Therefore, when simultaneously processing Si wafers having different diameters, it is necessary to prepare a boat having a different diameter, which is uneconomical and complicated. An object of the present invention is to simultaneously oxidize, diffuse, or carbonize semiconductor wafers having different diameters using the same boat.
A wafer holder and a semiconductor manufacturing apparatus capable of performing VD processing are provided.

[0009]

In order to achieve the above object, according to the present invention, a holder used in a horizontal state and surface treatment of a semiconductor wafer, which has a circular shape with a predetermined diameter, or a donut shape, or A semi-circular flat plate is provided with a plurality of wafer holding claws corresponding to the diameter of the semiconductor wafer to be mounted at a predetermined position, and the SiO
Disclosed is a semiconductor wafer holder characterized by being composed of one kind of material selected from the group consisting of ₂ , SiC, SiN and Si.

In the semiconductor wafer holder,
It may be formed by forming one rectangular hole into which a fork for transportation enters, which is slightly wider than the width of the fork and is cut from the periphery of the flat plate toward the center to be longer than the radius of the flat plate.

Further, according to the present invention, there is provided a reaction chamber for accommodating and processing a boat in which a plurality of semiconductor wafers of a prescribed size are loaded in a horizontal state, and a semiconductor wafer to be loaded in the boat in the reaction chamber. A carry-in system that carries in from outside,
In addition, the carry-in system carries in a semiconductor wafer of a specified size or a semiconductor wafer smaller than the specified size which is still mounted on the semiconductor wafer holder according to claim 1 or 2 from the outside, A semiconductor manufacturing apparatus is disclosed in which the loaded semiconductor wafer is mounted horizontally on a boat.

[0012]

The wafer retaining claws prevent accidents in which the semiconductor wafer falls from the holder or moves out of the holder during transportation. The diameter of the wafer holder
The depth of the boat post groove beforehand, ie (D-2W) and D
If the size is set to a value between and, a plurality of wafers having different diameters can be stably placed on the same boat by using the wafer holder in which the position of the clasp is changed. If a rectangular hole is provided in the wafer holder in advance, the wafer holder can be installed in the boat in advance, and the wafer taken out from the cassette can be placed thereon by a fork, which is convenient. The rectangular holes also serve to reduce the surface area of the wafer holder and suppress retention of reactive gases.

[0013]

EXAMPLES The present invention will be described in more detail based on the following examples. FIG. 1 is a perspective view showing the shape of a wafer holder according to an embodiment. In FIG. 1A, four retaining claws 15 are provided at predetermined positions on the upper surface of the wafer holder 11. The wafer holder 11 has the same diameter as, for example, a Si wafer having a diameter of 8 inches, and the retaining claw 15 is provided so as to fit a wafer having a diameter of 6 inches, for example. The material of 11 and 15 is usually quartz (SiO ₂ ), but it may be SiC or SiN, which is a Si-based compound, or Si itself.

8 of Si, which was chemically polished after the surface was mirror-finished
For example, 5 inch wafers 7 and 6 inch wafers 7'are prepared respectively, and the 6 inch wafers 7'are of a holder partitioned by the retaining claws 15 on the wafer holder 11 as shown in FIG. 1 (B). Placed on top. The 8-inch φ wafer 7 is not placed on the wafer holder 11. Then, the 8-inch φ wafers 7 and the wafer holders 11 are alternately housed in the cassette 12 one by one. After the storage, the cassette 12 is moved to the vicinity of the wafer transfer mechanism 13. The fork 14 of the wafer transfer mechanism 13 is driven to take out the Si wafers 7 and the wafer holders 11 in the cassette 12 one by one from the top and stack them on the boat 8 in that order. At this time, the boat 8 is at the solid line position in FIG.
The boat 8 is for an 8-inch φ wafer and is set on the boat holder 20. Si wafer 7 and S
The wafer holder 11 on which the i-wafer 7'is mounted is
Both are neatly stored in the groove 10 of the boat 8.

After that, the boat holder 20 is lifted up to the position shown by the dotted line in FIG. 4, the quartz bell jar held right above the boat bell 20 is lowered from above, and the lower end thereof is brought into close contact with the lower end of the boat holder 20. After driving the exhaust system 4 to evacuate the reaction chamber 1 in the quartz bell jar, the cock (not shown) of the gas system 3 is opened to fill the reaction chamber 1 with high-purity oxygen gas, and then the exhaust system 4 and The heater 2 is heated while interlocking. After reaching a predetermined oxidation temperature, an oxygen gas containing water vapor was introduced to oxidize the surface of the wafer. After a lapse of a predetermined time, the inflow gas was switched to high-purity argon to lower the temperature, the boat holder 20 was lowered, and the boat 8 was taken out. When the thickness of the oxide film formed on each wafer 7 and 7'is examined, the Si wafer 7 of 8 inches φ directly mounted on the boat 8 is also mounted on the wafer holder 11 and mounted on the boat 8 6 inches. φ Si
The wafer 7'had almost no change, and an oxide film having a thickness as expected was obtained according to the oxidation temperature, the partial pressure of water vapor, and the oxidation time. It was found that the quality of each oxide film (mechanical defects and electrical properties) did not change at all.

FIG. 2 is a perspective view showing the shape of a semiconductor wafer holder according to another embodiment of the present invention. Figure 2
2A and 2B show a holder shape corresponding to the presence / absence of a wafer, and FIGS. 2C and 2D show the state of a boat in which the holder is installed. As shown in FIGS. 2A and 2B, the semiconductor wafer holder 11 according to the present embodiment is characterized in that one rectangular hole 30 corresponding to the size of the fork 14 of the wafer transfer mechanism 13 is provided. is there. The rectangular hole 30 is cut inward from the periphery of the wafer holder 11 toward the center by a distance slightly longer than its radius D / 2, and the width of the rectangular hole is slightly wider than the size of the fork 14. The rectangular hole 30 is provided at a position where the retaining claw 15 is not lost.

When the present wafer holder 11 is used, as shown in FIG. 2 (C), only the wafer holder 11 is stacked and mounted on the boat 8 before the wafer is transferred, and pretreatment is performed in advance to the cassette 12. A stored small area wafer, for example, a 6 inch φ Si wafer 7 ′ is taken out by the fork 14 of the transfer mechanism 13, and the Si wafer 7 ′ is held in the wafer holder 11 while utilizing the rectangular hole 30 as shown in FIG. 2D. It can be neatly stored between the clasps 15 of the. In addition, oxidation, diffusion, or C in the reaction chamber 1
Wafer holder 1 mounted on boat 8 after VD processing
1, the Si wafer 7 ′ alone is taken out by using the fork 14 and the wafer is stored in the cassette 12, and the wafer to be newly processed is placed on the wafer holder 11 still mounted on the boat 8 by the fork 14. can do.

Since such a small area wafer is transferred in the same pattern as a large area, for example, an 8 inch φ Si wafer, there is no waste of time and the wafer holder 11 is messed up when the wafer is exchanged. It never happens.

Wafer holder 11 having a rectangular hole 30
Has a smaller surface area than that of the perfect circular type of the previous example, and thus it does not hinder the gas flow at the time of reaction, so higher reproducibility can be expected. In that sense, the shape of the semiconductor wafer holder 11 is preferably a semi-circular shape or a donut shape, which has a smaller surface area than the circular shape described in the above embodiments.

Although the material of the semiconductor wafer holder 11 is made of quartz in the above-mentioned embodiments, other Si-based materials such as SiC and S are used when the Si wafer is processed.
iN, Si, etc. can be used. These materials can also be used as the material for coating only the surface area of the wafer holder.

Further, in the above embodiments, only the case where the semiconductor to be processed is Si is described, but it is obvious that the present invention can be applied to other semiconductors, for example, wafers such as GaAs and ZnS.

[0022]

As described above, according to the present invention, a large number of semiconductor wafers having different diameters can be simultaneously surface-treated in an electric furnace. As a result, it is considered that the space storage efficiency is improved, and at the same time, it is possible to contribute to the reduction of the manufacturing cost of semiconductor devices and the production of various kinds in small quantities.

[Brief description of drawings]

FIG. 1 is a perspective view of a semiconductor wafer holder according to an embodiment.

FIG. 2 is a perspective view of a semiconductor wafer holder according to another embodiment.

FIG. 3: Oxidation, diffusion, CV for semiconductor device manufacturing
It is a block diagram of the apparatus which performs D process.

FIG. 4 is a main configuration diagram of a vertical device that performs an oxidation, diffusion, and CVD process.

FIG. 5 is a sketch of a conventional boat.

FIG. 6 is a partial cross-sectional view showing a wafer storage / storage unit (groove) of the boat.

FIG. 7 is a plan view showing a wafer storage state of the boat shown in FIG.

[Explanation of symbols]

 1 Reaction Chamber 2 Heater 3 Gas System 4 Exhaust System 5 Wafer Transfer Unit 6 Controller 7, 7'Si Wafer 8 Boat 9 Support 10 Groove 11 Semiconductor Wafer Holder 12 Cassette 13 Wafer Transfer Mechanism 14 Fork 15 Clasp 20 Boat Holder

Claims (3)

[Claims] 1. A holder used for horizontally transporting and surface-treating a semiconductor wafer, which is placed at a predetermined position of a circular, donut-shaped or semi-circular flat plate having a predetermined diameter. A plurality of wafer retaining pawls corresponding to the diameter of the semiconductor wafer to be formed are fixed, and are composed of one kind of material selected from the group consisting of SiO ₂ , SiC, SiN and Si. Semiconductor wafer holder to be used. 2. A semiconductor wafer holder is formed with a rectangular hole, which is wider than the width of the fork and is longer than the radius of the flat plate from the periphery of the flat plate so that the fork for transportation enters the semiconductor wafer holder. The semiconductor wafer holder according to claim 1, wherein 3. A reaction chamber for accommodating and processing a boat loaded with a plurality of semiconductor wafers of a prescribed size in a horizontal state, and a semiconductor wafer to be loaded in the boat in the reaction chamber from outside. And a semiconductor wafer having a prescribed size, or a semiconductor wafer smaller than the prescribed size which is still mounted on the semiconductor wafer holder according to claim 1 or 2. A semiconductor manufacturing apparatus in which semiconductor wafers are loaded from the outside and the loaded semiconductor wafers are placed horizontally on a boat.