JP2002110771A - Semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent slippage of a wafer support part produced due to excessive temperature difference by reducing the excessive temperature difference in a wafer, when high speed temperature increase and temperature decrease processing is conducted. SOLUTION: A semiconductor manufacturing device is provided with a vertical reactor, a heater for heating the water W inserted in the reactor provided so as to surround the outside, and a vertical boat 30 mounting a number of the wafers in a laminating state in the vertical direction to insert and remove them in the reactor and increases and decreases the temperature of the board of the inside of the reactor at a prescribed high speed. A plurality of ring holders 32 for mounting the wafers W at prescribed intervals in the vertical direction are provided on the vertical boat 30, a wafer-mounting recess part 34 having the level difference of the thickness of the wafer or thicker is provided on the upper face inner peripheral part of the ring holder 32, and a distance A from the outer peripheral edge of the ring holder 32 to the outer peripheral edge of the recess part 34 is set on the basis of a vertical interval H of the ring holder 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical diffusion apparatus, a vertical CVD apparatus, and the like having, as a reaction furnace, a high-speed heating / cooling rate furnace for heating / cooling at a higher speed than a general heating / cooling rate. A semiconductor manufacturing apparatus.

[0002]

2. Description of the Related Art In a conventional semiconductor manufacturing apparatus such as a vertical diffusion apparatus or a vertical CVD apparatus, a vertical boat is used as a means for taking a wafer (substrate) into and out of a vertical reaction furnace. A large number of wafers are mounted on a boat in a horizontal position in multiple stages in the vertical direction for processing.

FIG. 3 shows an example of a conventional semiconductor manufacturing apparatus. In FIG. 3, reference numeral 1 denotes a vertical reactor, 2 denotes a gas outlet provided at the upper end of the vertical reactor 1, 3 denotes a gas supply path for feeding a processing gas into the gas outlet 2, and 4 denotes a vertical reactor. A gas discharge path 5 provided in the lower part of the furnace 1 is a boat cap for closing a lower end opening of the vertical reactor 1, and 10 is a vertical boat mounted on the cap 5. Although not shown, a heater for heating the atmosphere in the vertical reactor 1 is provided around the vertical reactor 1.

[0004] A wafer (substrate) W is loaded into the reactor 1 in a form mounted on a vertical boat 10 in a horizontal posture. FIG. 4 shows a configuration of a vertical boat used in a conventional semiconductor manufacturing apparatus. As shown in FIG. 4A, the vertical boat 10 has ring-shaped end plates 12 at upper and lower ends.
13 are arranged, and three or four columns 14 are erected in parallel with each other at predetermined intervals in the circumferential direction between the upper and lower end plates 12 and 13. As shown in FIG.
As shown in (b), a large number of slits 15 are formed horizontally at regular intervals in the vertical direction, so that a large number of wafer holding claws 16 for supporting the peripheral portion of the semiconductor wafer W are provided in a protruding manner. By mounting the semiconductor wafer W on the wafer holding claws 16, a large number of wafers W can be mounted in a stacked state in the vertical direction.

The wafer W is processed in a high-temperature atmosphere while, for example, flowing a processing gas in the order of a gas supply path 3 → a gas outlet → the inside of the reactor 1 → a gas discharge path 4.

[0006]

However, in order to reduce the thermal budget and improve the throughput with the increase in the degree of integration of semiconductor devices, the temperature of a conventional vertical diffusion apparatus or vertical CVD apparatus is increased at a high speed.・ Temperature lowering treatment has become necessary.

However, when a high-speed temperature raising / lowering process is performed by using a boat 10 as shown in FIG. 4, which is used in a normal vertical reactor, a large amount of water is left in the wafer W during the temperature raising / lowering. There is a problem that a temperature difference occurs. For example, 8
In the case of an inch wafer, a temperature difference of about 60 ° C. or more may occur when the temperature rise / fall rate is 50 ° C./min at a wafer interval of 5.2 mm. In this case, when the temperature rises, the temperature distribution becomes concave (temperature distribution is low at the center and the temperature is high at the periphery), and when the temperature falls, the temperature distribution becomes convex (temperature distribution is high at the center and the temperature is low at the periphery). .

When such an excessive temperature difference occurs in the wafer surface, the temperature difference generates a thermal stress in the wafer, causing the wafer W to bend, and the wafer holding claws 16
Above, there was a problem that a slip occurred in the wafer W.

When the cause of the excessive temperature difference in the wafer surface was examined, the interval between the wafers W mounted in a stacked state was narrow, and the wafer was not radiated by radiant heating from the outer peripheral side of the wafer. It was found that there was a cause for the uniform heating.

That is, when the temperature is raised, the wafer is heated by radiant heat from a heater (heating source) on the outer peripheral side of the wafer. However, since the vertical interval between the wafers is small, the radiant heat does not spread evenly over the entire surface of the wafer. First, the outer peripheral portion of the wafer is heated by the radiant heat of the heater, and heat is transmitted from the outer peripheral portion of the wafer to the lower central portion of the wafer by heat conduction. After a certain period of time, the entire surface of the wafer has a uniform temperature. Since the rate of temperature rise is faster than the speed of heat transfer due to heat conduction in the wafer surface, the temperature uniformity over the entire wafer is delayed, and a concave temperature distribution occurs in the wafer surface.

In addition, when the temperature is lowered, the amount of radiant heat incident on the outer peripheral portion of the wafer decreases with time, and the heat escapes from the outer peripheral portion of the wafer to the outside by convection or heat conduction. Although the temperature of the peripheral part decreases faster than the central part of the wafer, the speed of heat transfer by heat conduction from the central part of the wafer to the peripheral part of the wafer is lower than that of the heater. The delay in homogenization causes a convex temperature distribution in the wafer surface.

In view of the above circumstances, the present invention reduces an excessive temperature difference in a wafer surface when performing a temperature increase / decrease process at a higher speed than usual, and reduces a wafer supporting portion generated by the excessive temperature difference. An object of the present invention is to provide a semiconductor manufacturing apparatus capable of preventing a slip.

[0013]

According to the first aspect of the present invention, there is provided a vertical reactor in which substrates are loaded and unloaded from a lower end opening, and a vertical reactor which is provided so as to surround the outside of the vertical reactor. A heater that heats the inserted substrate; and a vertical boat that mounts and stacks a large number of substrates in the vertical direction and that is inserted into and out of the vertical reaction furnace. In a semiconductor manufacturing apparatus that raises and lowers the temperature of a substrate in a reaction furnace at a speed, the vertical boat is provided with a plurality of ring holders on which substrates are mounted at predetermined intervals in a vertical direction, and an inner peripheral surface of an upper surface of the ring holder. The substrate mounting part having a step larger than the thickness of the substrate is provided in the part, and the distance from the outer edge of the ring holder to the outer edge of the substrate mounting part is set based on the vertical distance of the ring holder. And

When a wafer (substrate) is heated and cooled at a high speed using a conventional vertical boat, an excessive temperature difference occurs in the wafer surface, and a slip occurs in a wafer support portion. The cause of this temperature difference is that, due to the non-uniformity of the radiant heating in the wafer surface, the temperature uniformization speed in the wafer surface due to heat conduction cannot follow the temperature rise / fall speed of the heater. .

In view of the above, according to the first aspect of the present invention, the boat is provided with "walls" for blocking heat radiation from the heater to the outer peripheral surface of the wafer. That is, a boat is provided with a plurality of ring holders on which substrates are mounted at predetermined intervals in the vertical direction, and a substrate mounting portion having a step greater than the thickness of the substrate is provided on the inner peripheral portion of the upper surface of the ring holder. The thick part outside the mounting part functions as a "wall" that blocks radiant heat.

By doing so, it is possible to limit the amount of radiant heat incident on the outer peripheral portion of the wafer when the temperature is raised at a high speed, and to reduce the escape of heat (radiation) from the outer peripheral portion of the wafer when the temperature is decreased at a high speed. .

Further, since the ring-shaped "wall" surrounds the outer peripheral portion of the wafer, the wafer receives only the radiant heat incident from the gap between the upper and lower ring holders. Therefore, in the invention of claim 1, the thickness of the ring-shaped “wall”, that is, the distance from the outer peripheral edge of the ring holder to the outer peripheral edge of the substrate mounting portion is based on the vertical interval of the ring holder. By setting to a predetermined value, the incident angle of the heat ray incident on the outer peripheral portion of the substrate through the gap between the upper and lower ring holders is limited to a predetermined value or less, and the incidence of radiant heat on the outer peripheral portion of the wafer is reduced as much as possible. .

As a result, when there is a “wall” on the outer periphery of the wafer, the outer peripheral portion of the wafer is heated with a smaller amount of radiation heat than when there is no “wall”. In other words, when the temperature rises, heat is transmitted from the outer peripheral portion of the wafer to the lower central portion of the wafer by heat conduction, so that the entire surface of the wafer has a uniform temperature. Because the amount of radiant heat to be reduced is reduced, the temporal change of the increased radiant heat is small, the temporal change of the temperature rise rate is also small, and the temperature difference between the wafer outer peripheral portion and the central portion is smaller than when there is no `` wall ''. Is also smaller.

On the other hand, when the temperature is lowered, since the amount of incident radiant heat is small, the time change of the reduced radiant heat is smaller than when there is no "wall", and the rate of temperature decrease due to radiation at the outer peripheral portion of the wafer is also small. In addition, when the heat capacity of the ring holder is set to have substantially the same heat capacity as that of the wafer, the amount of radiant heat incident on the ring holder becomes larger than the amount of radiant heat incident on the wafer. Walls are formed, the escape of heat from the outer periphery of the wafer to the outside can be reduced, and the difference between the temporal change in the temperature at the center of the wafer and the temporal change in the temperature at the outer periphery of the wafer is small. Become. That is, the temperature difference in the wafer surface decreases.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view illustrating a schematic configuration of a vertical CVD apparatus as a semiconductor manufacturing apparatus according to an embodiment.
In this vertical CVD apparatus 20, a hollow heater 21 is provided.
A vertical reaction furnace 23 is installed therein via a soaking tube 22 so that the wafer W inserted into the reaction furnace 23 can be heated from the outer peripheral side. The heat equalizing tube 22 is made of a material having a large heat capacity, and is used for maintaining temperature uniformity in the furnace.

The reaction furnace 23 is provided with a gas introduction passage 24, and the tip of the gas introduction passage 24 is connected to a gas shower room 25 at the ceiling of the reaction furnace 23. Further, an exhaust passage 26 is provided at a lower portion of the reaction furnace 23, and the processing gas blown out from the gas shower chamber 25 into the reaction furnace 23 flows through the inside of the reaction furnace 23 from the top to the bottom, and the exhaust passage 26 is formed.
From outside the furnace.

The reaction furnace 23 has an opening with its lower end opened to serve as an entrance, from which the wafer W loaded in the vertical boat 30 can be introduced into or taken out of the reaction furnace 23. . The boat 30 is raised and lowered by a boat elevator (not shown), thereby
3 and taken out of the reaction furnace 23.
The boat 30 is erected on the boat cap 27,
The boat cap 27 is provided on the furnace lid 28.

The boat 30 in this case is shown in FIG.
As shown in (b), three (or four) columns 31 may be used.
A plurality of shelf-plate-shaped ring holders 32 for mounting wafers W are attached at regular intervals in the vertical direction. The interval H between the upper and lower ring holders 23 is set to a size (for example, 2 to 3 mm) into which the tweezers can be inserted, and the tweezers are provided at one location in the circumferential direction of each ring holder 32 and at several locations on the inner circumference of the ring holders 32. Cutouts 33A and 33B are provided as escapes for the above.

In the inner peripheral portion of the upper surface of the ring holder 32, a concave portion 34 for mounting a wafer having a level difference larger than the thickness of the wafer W is provided. The wafer mounting concave portion 34 forms a substrate mounting portion. In order to place the wafer W at a fixed position on the bottom surface 34a of the concave portion 34, the peripheral surface 34b of the concave portion 34 is formed as a tapered surface. In this case, the recess 3
4 is set to be larger than the diameter of the wafer W by, for example, about 2 to 3 mm, and the width t of the concave portion 34 is set to, for example, 3 to 4 m.
m. The distance A from the outer peripheral edge of the ring holder 32 to the outer peripheral edge of the concave portion 34 is the ring holder 3.
It is set to a predetermined value based on the interval H in the up-down direction of No. 2. For example, the smaller the vertical interval H between the ring holders 32, the smaller the distance A.

Here, the thick portion on the outer peripheral side of the concave portion 34 is
This is a portion existing as a ring-shaped “wall” on the outer peripheral side of the wafer W, and the thickness A of the ring-shaped “wall” is set to a predetermined value based on the vertical interval H of the ring holder 32. Thus, the incident angle θ of the heat ray incident on the outer peripheral portion of the wafer W through the gap between the upper and lower ring holders 32 is limited to a predetermined value or less, and the incidence of radiant heat from the heater 21 to the outer peripheral portion of the wafer W is reduced as much as possible. ing. Further, the volume of the ring holder 32 is set such that the heat capacity of the ring holder 32 is substantially equal to the heat capacity of the wafer W. In this case, the incident angle θ can be reduced by increasing the distance A. In addition, by increasing the distance A, the heat capacity around the wafer W can be increased, and the temperature cooling around the wafer during rapid cooling can be eased.

In this apparatus, the heating rate by the heater 21 is set to a high speed of, for example, + 40 ° C./min.
The cooling rate is set to a high speed of, for example, -20 ° C./min. That is, the temperature is set to rise and fall at a speed higher than the speed of heat transfer by heat conduction in the wafer surface.

Next, the operation will be described. When processing the wafer W, the wafer W is placed in the recess 34 of each ring holder 32 of the boat 30 and inserted into the reaction furnace 23 maintained at an appropriate furnace temperature by a boat elevator. Next, the inside of the reaction furnace 23 is exchanged with gas, and at the same time, the furnace atmosphere is heated at a high speed, and while maintaining a predetermined temperature, a processing gas is introduced into the reaction furnace 23 to perform predetermined processing on the wafer W. Next, the temperature inside the reaction furnace 23 is lowered at a predetermined high speed, and when the temperature has dropped to the predetermined temperature, the boat 30 is taken out of the furnace.

At the time of the above-mentioned high-speed heating, the thick portion outside the concave portion 34 on which the wafer W is placed functions as a "wall" for blocking the radiant heat from the heater 21, so that there is no conventional "wall". The outer peripheral portion of the wafer W is heated with a smaller amount of radiant heat than when the boat is used. In other words, at the time of temperature rise, heat is transmitted by heat conduction from the outer peripheral portion of the wafer to the lower central portion of the wafer, so that the entire surface of the wafer has a uniform temperature. Since the amount of radiant heat incident on the outer peripheral portion of the wafer is reduced, the temporal change of the increased radiant heat is reduced, and the temporal change of the temperature rise rate is also reduced,
The temperature difference between the outer peripheral portion and the central portion of the wafer is smaller than in the conventional case having no “wall”.

At the time of high-speed cooling, the amount of incident radiant heat is small, so that the time variation of the reduced radiant heat is smaller than that in the case of using a conventional boat having no "wall", and the temperature decrease due to radiation at the outer peripheral portion of the wafer. The rate also gets smaller. Further, since the heat capacity of the ring holder 32 is set to have substantially the same heat capacity as that of the wafer W, the amount of radiant heat incident on the ring holder 32 becomes larger than the amount of radiant heat incident on the wafer W. A state in which a heat wall is formed on the outer peripheral portion of. Therefore, the escape of heat from the outer peripheral portion of the wafer W to the outside is reduced, and the difference between the temporal change of the temperature at the central portion of the wafer and the temporal change of the temperature at the outer peripheral portion of the wafer W is reduced, and the temperature difference within the wafer surface is reduced. But,
It is smaller than the conventional case without "walls".

Then, the temperature difference in the wafer surface at the time of raising and lowering the temperature can be reduced to 10 to 20 ° C.,
The stress generated on the wafer W can be reduced, and the occurrence of slip can be prevented.

In the above embodiment, the case where the present invention is applied to a vertical CVD apparatus has been described, but the present invention can also be applied to a vertical diffusion apparatus.

[0032]

As described above, according to the present invention,
On a boat on which a large number of substrates are mounted, a plurality of ring holders for mounting the substrates at predetermined intervals in the vertical direction are provided, and a substrate mounting portion having a step greater than the thickness of the substrate is provided on the inner peripheral portion of the upper surface of the ring holder. Since the distance from the outer edge of the ring holder to the outer edge of the substrate mounting portion is set based on the vertical spacing of the ring holder, radiant heat incident on the outer edge of the substrate during high-speed temperature rise is reduced, It is possible to reduce heat radiation from the outer peripheral portion of the substrate when the temperature is lowered, and to reduce the temperature difference generated in the surface of the substrate when the temperature is rapidly raised and lowered. Therefore, even when the temperature is raised or lowered at a higher speed than usual, a substrate (wafer) for a semiconductor device can be produced without slip, thereby improving the throughput and reducing the cost of the substrate. Can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a boat of the same apparatus, where (a) is the I of FIG. 1;
FIG. 2B is a sectional view taken along the line Ia-IIa, and FIG.
FIG.

FIG. 3 is a schematic configuration diagram of a conventional semiconductor manufacturing apparatus.

FIG. 4 is a configuration diagram of a boat of a conventional semiconductor manufacturing apparatus;
4A is an overall perspective view, and FIG. 4B is an enlarged view of a portion taken along line IVb in FIG.

[Explanation of symbols]

 Reference Signs List 20 vertical CVD apparatus 21 heater 23 reactor 30 boat 32 ring holder 34 recess W wafer (substrate)

Continuing on the front page (72) Inventor Wakako 3-14-20 Higashinakano, Nakano-ku, Tokyo International Electric Co., Ltd. (72) Inventor Eiji Hosaka 3--14-20 Higashi-Nakano, Nakano-ku, Tokyo International Electric Co., Ltd. Reference) 4K030 FA10 GA02 KA04 KA23 LA15 5F031 CA02 FA01 FA12 HA64 HA65 MA28 5F045 BB01 DP19 EK06 EK30 EM08

Claims (1)

[Claims] A vertical reactor for loading and unloading substrates from a lower end opening; a heater provided to surround the outside of the vertical reactor and heating a substrate inserted into the reactor; A vertical boat which is loaded with a large number of substrates in a stacked state in the direction and is taken in and out of the vertical reactor, and controls the heater to raise and lower the temperature of the substrates in the reactor at a predetermined high speed. In the semiconductor manufacturing apparatus, the vertical boat is provided with a plurality of ring holders on which substrates are placed at predetermined intervals in a vertical direction, and a substrate mounting having a step at least equal to the thickness of the substrate on the inner peripheral portion of the upper surface of the ring holder. A semiconductor manufacturing apparatus, wherein a mounting portion is provided, and a distance from an outer peripheral edge of the ring holder to an outer peripheral edge of the substrate mounting portion is set based on a vertical interval of the ring holder.