JPH02216820A - Heat-treatment device of semiconductor wafer - Google Patents

Abstract

PURPOSE:To enable two semiconductor wafers to be subjected to heat treatment at high speed and in a short time by providing a supporting means for performing insertion and take-out while supporting two semiconductor wafers in a heating space of a heat-treatment device and a screening means for screening between the semiconductor wafers stored within the heating space. CONSTITUTION:When signal for starting heat treatment is input to a control part 24, signal is transmitted from a controller 25 to a carrying system and a take-out tool 18 take out two wafers 8 from a first cassette 17 and then carries them onto a load tool 19. Then, the load tool 19 moves horizontally, mounts two wafers 8 on an insertion tool 7, moves to the upper part, and then stores them within a high- temperature furnace 1. At this time, a screening plate 9 is inserted between two wafers 8. After the wafers 8 are heated for a specified amount of time within the high- temperature furnace 1, the insertion tool 7 moves to a lower part, the unload tool removes the wafers 8, and the wafers 8 which are fully cooled by a cooling board 22 are stored in a second cassette 23 by a storing tool 21. At this time, the moving speed of the insertion tool 7 in up and down directions prevents temperature distribution to be generated within the surface of the wafers 8. Thus, the speed should be for example 150mm/sec or higher.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a diffusion device, a vapor phase thin film forming device (a semiconductor wafer heat treatment device used in CVD equipment, etc.), and particularly relates to a semiconductor wafer heat treatment device used in CVD equipment, etc.
6. Related to a semiconductor wafer heat treatment apparatus suitable for simultaneously and uniformly heat-treating two semiconductor wafers for a short time [Prior art] A conventional semiconductor wafer heat treatment apparatus is disclosed in Japanese Patent Application Laid-Open No. 60-17
As described in Japanese Patent No. 1723, the bottom of a vertical cylindrical high-temperature furnace is opened, and horizontally supported wafers are inserted one by one into the high-temperature furnace from below.

It was designed to heat the wafer.

[Problem to be solved by the invention]

However, the above-mentioned conventional technology does not give consideration to uniformly heating two semiconductor wafers at the same time for a short period of time, and there is a problem in that productivity is poor when heating one semiconductor wafer at a time. Further, when two wafers are stacked and heated at the same time, there is a problem in that the temperature difference between each wafer and the temperature difference within the wafer surface becomes very large.

The present invention has been made in view of the above circumstances, and is capable of heating two semiconductor wafers simultaneously and uniformly.
An object of the present invention is to provide a heat treatment apparatus for semiconductor wafers in which thermal stress defects do not occur.

(1 [Means for Solving M]) In order to achieve the above object, the present invention forms a heating space in the furnace by a heater provided inside the high-temperature furnace, and stores semiconductor wafers in the heating space for heat treatment. In the semiconductor wafer heat treatment apparatus, there is provided a support means for supporting the two semiconductor wafers substantially parallel to each other and inserting and removing the semiconductor wafers into the heating space; A partition means is provided to partition the wafers.

[Effect]

According to the above configuration, when a low-temperature semiconductor wafer is stored in a high-temperature heating space, the high-temperature partition plate enters between the two wafers, so the partition plate becomes a heat source and heats the opposing surfaces of the wafers. . Furthermore, since the outer surface of each wafer is heated from the inner wall of the high-temperature furnace, the temperature of both wafers increases simultaneously due to double-sided heating, making it possible to reduce the difference in temperature distribution that occurs within the wafer surface during a transient period.

[Example] Hereinafter, an example of a semiconductor wafer heat treatment apparatus according to the present invention will be described with reference to the drawings.

A first embodiment of the present invention is shown in FIGS. 1 to 5. A high-temperature furnace 1 has a rectangular parallelepiped shape as shown in FIG. Heaters 2 are provided in parallel and facing each other. Each of these heaters 2 has five heat generating areas 2a.

2b, 2c, 2d, 2e, and 2f, 2g, 2h.

The heater 2 is divided into 2i and 2j, and these heaters 2 are formed by winding a Kanthal resistance heating element. As shown in FIGS. 1 and 2, a heat insulating material 3 is provided around the outer periphery of these heaters 2, and a heat equalizing tube 4 made of silicon carbide or the like and a heat soaking tube 4 made of quartz glass or the like are provided inside. A reaction tube 5 is provided. And these insulation materials 3. The soaking tube 4 and the reaction tube 5 are each supported by a pedestal 35 via a flange 6 made of stainless steel or the like, thereby forming the high temperature furnace 1.

A wafer insertion jig 7 that supports two semiconductor wafers 8 is inserted into the reaction tube 5 from below the high temperature furnace 1 in a substantially vertical state. At this time, a rectangular partition plate 9 is provided so as to fit between the two wafers 8, and this partition plate 9 is fixed to the reaction tube 5. Further, the lower end of the insertion jig 7 is attached to a vertical conveyance table 10, and is moved up and down by this vertical conveyance table 10. Reaction tube 5 and soaking tube 4
A prism 11 is provided at a position facing the center of the wafer 2 inserted between the The light is reflected by the mirror 12 and enters the radiation hygrometer 13. The temperature signal of the wafer 8 measured by the radiation thermometer 13 is transmitted to the heat treatment temperature controller 26.

As shown in FIG. 4, a partition plate 9 is fixed to the inner circumference of the reaction tube 5 into which the wafer 8 is inserted, and gas supply pipes 14 are provided on both left and right sides.

Nitrogen, argon, and oxygen flow in from the inlet port 15 connected to an external air supply pipe (not shown).

Processing gas such as water vapor is preheated while rising in the gas supply pipe 14 and is supplied to the upper part of one reaction tube 5 . Further, inside the six reaction tubes 5, which are formed so that the flow path lengths of the left and right gas supply tubes 14 are equal, the processing gas that has been preheated to a high temperature and is supplied flows downward.
It is discharged into the atmosphere from the lower end of the reaction tube 5. Note that reference numeral 16 in the figure is a claw for fixing the reaction tube 5 to the flange 6.

FIG. 5 shows a diffusion device equipped with a high temperature furnace 1 configured as described above. As shown in FIG. A take-out jig 18 takes out two wafers 8 from the first cassette and moves them upward, and a receiver takes the wafers 8 from the take-out jig 18, brings them close to the high temperature furnace 1, and delivers them to the wafer insertion jig 7. A loading jig 19 is provided. Similarly, an unloading jig 20 receives the heated wafer 8 from the wafer insertion jig 7 and supplies it to the cooling board 22, and the heated wafer 8 is transferred from the cooling board 22 to the second cassette 23.
A storage jig 21 for transferring is provided. Further, a control section 24 is provided near the high temperature furnace 1 to control the operation of each section.

Furthermore, as shown in FIG. 3, the heater 2 is divided into 10 heat generating areas 2a to 2j, and the amount of heat generated in these areas is 4.
It is divided into two zones and controlled.

That is, the heaters 2b and 2g are in the central zone, and the heater 2a is in the central zone.
, 2f is the upper zone, heaters 2c and 2h are the lower zone,
Heaters 2d, 2a, 2i, and 2j are in side zones.

Next, the operation of heat-treating the wafer 8 using the diffusion device configured as described above will be described. First, the operator must set the heat treatment conditions, for example, at a temperature of 1000°C and a heating time of 3.
The processing gas nitrogen is input to the control unit 24. Control unit 24
A signal of the above conditions is transmitted from the main controller 25 located in the heater 2 to the heat treatment temperature controller 26, and from this heat treatment temperature controller 26 the heater temperature controller 27a to 27d provided for each zone of the heater 2 is informed of the heater set temperature. is given. At this time, a set temperature is given to the heater temperature controller 27b in the central zone so that the internal temperature of the high temperature furnace becomes the heat treatment temperature. Further, the lower zone heater temperature controller 27c is set at a temperature higher than the set temperature for the central zone in order to cancel out the heat radiation from the lower insertion port of the high temperature furnace 1 and the influence of the insertion jig 7. Further, the set temperatures of the upper zone and the side zones are set so that the temperature within the surface of the wafer 8 becomes uniform. Further, the heater temperature controllers @27a to 27d for each zone control the heater power supplies 29a to 29d so that the temperatures indicated by the heater temperature sensors 28a to 28d provided in each zone approach the set temperatures, respectively. In addition, in the first @, a heater temperature controller 27d for the side zone, a temperature sensor 28d,
The illustration of the heater power source 29d is omitted.

Next, the operator sets the first cassette 17 containing the wafers 8 and the empty cassette 23 into the apparatus, and inputs a signal to the control section 24 to start the heat treatment. Then, a signal is transmitted from the controller 25 provided in the control unit 24 to the transport system, and the take-out jig 18 takes out the two wafers 8 from the first cassette 17 and transports them to the loading jig 19. 7 moves downward, and the loading jig 19 moves laterally to place the two wafers 8 on the insertion jig 7. The insertion jig 7 is then moved upward and housed inside the high temperature furnace 1 as shown in FIG. At this time, a partition plate 9 is inserted between the two wafers 8. After heating the second wafer 8 in the high temperature furnace 1 for a predetermined time, the insertion jig 7 moves downward, the wafer 8 is removed by the unloading jig, and the cooling board 22 is moved by the storage jig 21.
The wafer 8, which has been sufficiently cooled on the cooling board 22, is then transported to.

It is stored in the second cassette 23 by the storage jig 21. Each of the above operations is then repeated continuously. At this time, the moving speed of the insertion jig 7 for raising and lowering is set to 1, for example, in order to prevent temperature distribution from occurring within the surface of the wafer 8.
The speed shall be 50 mm/sec or more. Also, after heating the wafer 8
When moving downward, the reaction tube 5 may be temporarily stopped at the lower part of the reaction tube 5 and cooled slowly without being exposed to outside air.
When the supply of wafers 8 is interrupted, the insertion jig 7 is stored inside the high temperature furnace 1 and kept at a high temperature at all times.

Figures 6 and 7 show the results of numerical calculations regarding the transient changes in wafer temperature and wafer in-plane temperature difference.The calculation conditions were as follows: The diameter of the silicon wafer was 150 m, and the thickness of the quartz glass partition plate. 5m.

The distance between the wafers and the partition plate was 10 m, the distance between the wafers without the partition plate was 20 m1, and the wafer at 22°C was instantly inserted into a high temperature furnace at 1000°C. It can be seen from FIG. 6 that the wafer reaches the internal temperature of the high temperature furnace approximately 30 seconds after being inserted.

The temperature of the partition plate temporarily drops as the wafer absorbs heat, but it gradually returns to its original temperature. Furthermore, it can be seen from FIG. 7 that the in-plane temperature difference of the wafer becomes maximum when the center temperature is approximately 600°C. It can also be seen that when there is a partition plate, the temperature difference within the wafer surface is reduced by about half compared to when there is no partition plate. This is due to the following reason. In other words, when two room-temperature wafers are inserted into a high-temperature furnace without a partition plate, the outer surfaces of the two wafers are almost uniformly heated from the inner wall of the high-temperature furnace, but the inner surfaces In this case, the heating from the gap between the two wafers increases at the outer periphery, creating a temperature distribution within the wafer surface such that the outer periphery of the wafer becomes hot. Since the surface of the wafer is also heated by the high-temperature partition plate, the temperature distribution within the wafer surface is reduced.

In addition, in one reaction tube 5, the reason why the partition plate 9 is provided at the opposite position when the wafer 8 is completely inserted into the high temperature furnace 1 is that the processing gas flowing downward in the first reaction tube 5 is separated from the two wafers 8.
The purpose is to flow the same amount of water and to reduce the weight by 1.

Furthermore, the reason why the wafer 8 is slightly inclined by, for example, 5 degrees with respect to the vertical direction as shown in FIG. 1 is that the wafer 8 vibrates back and forth when the insertion jig 7 moves up and down. This is to prevent

In this case, since the inclination of the wafer 8 is slight, there is almost no difference in the heat transfer characteristics of the two wafers.

In FIGS. 8 and 9 showing the second embodiment of the present invention, parts that are the same as or equivalent to those of the first embodiment shown in FIGS. 1 and 2 are denoted by the same reference numerals. The feature of this embodiment is that the partition plate 9 inserted between the two wafers 8 has a disk shape with the same diameter as the wafer 2.
Furthermore, the outer peripheral portion 30 of the partition plate 9 is thinner than the central portion. This partition plate 9 is fixed to the reaction tube 5 via support members 31 provided in three directions, and the wafer 8 is placed on the insertion jig 7 in a vertical state.

The rest of the structure is the same as the first embodiment.

According to this embodiment, since the outer peripheral part 30 of the partition plate 9 is thinner than the central part, when the wafers 8 at room temperature are inserted into the high temperature furnace 1, the inner surfaces of the two wafers 8 are The outer periphery of the pin heated by the partition plate 9 becomes smaller. On the other hand, since the outer periphery of the inner surface of the two wafers 8 is heated from the distance between the wafers 8, the wafer 8 is heated uniformly over the entire surface due to the action of both, and the temperature distribution within the wafer surface is small. There is a certain effect.

In the above embodiment, the case where the shape of the partition plate 9 is a disk shape having the same diameter as the wafer 8 has been described, but the shape of the partition plate 9 may be as shown in FIGS. 10 to 13. In FIG. 10, the size of the partition plate 9 is larger than the wafer 8, and the portion facing the center of the wafer 8 is thicker. The thick portion is circular and its diameter is smaller than the diameter of the wafer 8. Also, the same effect as the second embodiment described above can be obtained.

The partition plate 9 in FIG. 11 has a disk shape and its diameter is smaller than the diameter of the wafer 8, and has the same effect as described above.

The partition plate 9 shown in FIG. 12 is larger than the wafer 8, and has a thick ring-shaped portion 32 facing the outer circumference of the wafer 8, and the diameter of this ring is larger than the diameter of the wafer 8. In this example.

When the wafers 8 at room temperature are inserted into the high-temperature furnace 1, the ring-shaped thick portion 32 acts to close the gap between the wafers 8, which has the effect of reducing the temperature distribution within the wafer surface.

The partition plate 9 in FIG.
Similar to the previous embodiment, 2 is a ring-shaped thick walled part, and a circular hole having a diameter approximately equal to that of the wafer 8 is formed inside the ring-shaped thick part. There is.

FIG. 14 and FIG. 15 show the third and fourth embodiments of the present invention, respectively.
In these figures showing the embodiment, the same or equivalent parts as in the first embodiment shown in FIG. The feature of the third embodiment shown in FIG. 14 is that two reaction tubes 5 are provided inside the soaking tube 4, and each wafer 8 is inserted one by one into each reaction tube 5 by a pair of insertion jigs 7. The point is that it is meant to be inserted.

These two insertion jigs 7 are attached to the same upper and lower transport table 10, and the two wafers 8 are heat-treated at the same time. In this case, a heat treatment chamber thermometer 34 is inserted between the soaking tube 4 and the reaction tube 5, and the heater set temperature is controlled by this thermometer 34.

This embodiment also provides the same effects as those of the embodiments described above.

The feature of the fourth embodiment shown in FIG.
A reaction tube 5 and a soaking tube 4 are provided in each of the
According to this embodiment, in which the heat insulating material 33 is provided between the two heat soaking tubes 4, the two wafers 8 are completely separated, so that the wafers 8 are heated completely uniformly. , no in-plane temperature variation distribution of the wafer 8 occurs.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a support means for supporting and inserting and removing two semiconductor wafers into a heating space of a heat treatment apparatus, and a partition means for partitioning between the semiconductor wafers housed in the heating space. This makes it possible to uniformly heat-treat two semiconductor wafers at the same time at high speed and in a short time, and because the temperature distribution within the wafer surface during heat treatment is small, it is possible to produce high-quality semiconductor wafers without thermal stress defects. Obtainable.

[Brief explanation of the drawing]

FIG. 1 shows a first part of a semiconductor wafer heat treatment apparatus according to the present invention.
A vertical cross-sectional view and a block diagram of the temperature control system showing an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of the high-temperature furnace in a cross section perpendicular to FIG. 1. Figure s3 is a transparent perspective view of the high-temperature furnace showing the heater division in Figure 1, Figure 4 is a perspective view showing the reaction tube in Figure 1, and Figure 5 is a diffusion device equipped with the high-temperature furnace according to this embodiment. FIG. 6 is a graph showing the calculation result of the temporal change in wafer temperature, FIG. 7 is a graph showing the calculation result of the temperature distribution within the wafer surface, and FIG. 8 is a graph showing the calculation result of the temperature distribution within the wafer surface. FIG. 9 is a vertical cross-sectional view in a direction perpendicular to FIG. 8, and FIGS. 10 to 13 are vertical cross-sectional views showing partition plates according to other embodiments of the present invention. Figure 14 and 1
FIG. 5 is a longitudinal cross-sectional view showing high temperature furnaces according to third and fourth embodiments of the present invention, respectively. 1... High temperature furnace, 2... Heater, 3... Insulating material, 4
... soaking tube, 5 ... reaction tube, 7 ... insertion jig, 8
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Claims (1)

[Claims] 1. In a semiconductor wafer heat treatment apparatus in which a heating space is formed in the furnace by a heater provided inside the high-temperature furnace, and a semiconductor wafer is housed in the heating space and heat-treated, the two semiconductor wafers are supported substantially in parallel. A heat processing apparatus for semiconductor wafers, comprising: support means for inserting and taking out the semiconductor wafers into and out of the heating space; and partition means for separating the semiconductor wafers when the semiconductor wafers are stored in the heating space.