JP3513639B2 - Semiconductor heat treatment apparatus and semiconductor substrate heating / cooling method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor heat treatment apparatus and a semiconductor substrate temperature raising / lowering method using the same.

[0002] In this specification, the term "heater" refers to a tubular member composed of a heat generating portion and a heat insulating wall supporting the heat generating portion, but the same applies to a heater whose upper end is closed by the heat insulating wall. I will use expressions.

[0003]

2. Description of the Related Art Conventionally, as a semiconductor heat treatment apparatus, a process tube which has a lower end opened and an upper end closed and which is surrounded by a heater, and a plurality of semiconductor substrates are vertically spaced from each other and are also supported. And a boat that can be inserted into the process tube when it moves up and down relative to the process tube and rises relative to the process tube, and a cooling gas passage is provided in a portion between the process tube and the heater. Are known to be formed.

In heat treatment of a semiconductor substrate using a conventional apparatus, a heater is used to set a predetermined temperature inside the process tube,
For example, after preheating to 700 ° C., a boat supporting a plurality of semiconductor substrates is inserted into the process tube in this state, the semiconductor substrates are heated by a heater to a predetermined heat treatment temperature, for example, 1100 ° C. And heat treatment in the presence of the desired atmospheric gas for a predetermined time, and then the temperature of the heater is lowered, and the cooling gas is introduced into the cooling gas passage to cool the semiconductor substrate to the above preheating temperature, and then the boat is removed from the process tube. It is done by taking it out. In such a treatment step, the reason why the inside of the process tube is preheated to a predetermined temperature even while the boat is present outside the process tube is to shorten the treatment time.

[0005]

However, it has been found that the following problems occur when the semiconductor substrate is heat-treated as described above using the conventional apparatus. That is, the heat treatment by the above-mentioned apparatus is a batch process, and in order to support a large number of semiconductor substrates in the boat for improving the productivity, the distance between the adjacent semiconductor substrates should be considerably small. Is preferred. In this case, each semiconductor substrate receives radiant heat from the heater at its peripheral portion when the semiconductor substrate is heated to the heat treatment temperature, and each semiconductor substrate receives heat from the peripheral portion to the outside when the semiconductor substrate is cooled from the heat treatment temperature. Radiate. When the temperature of the semiconductor substrate is raised to the heat treatment temperature and when the temperature is lowered from the heat treatment temperature, heat transfer in each semiconductor substrate is mainly performed by heat conduction. There is a problem that the difference becomes large and a thermal stress causes thermal strain. Such a problem becomes more prominent as the diameter of the semiconductor substrate increases or as the time required for raising and lowering the temperature decreases.

Further, in order to solve such a problem, it is sufficient to increase the interval between the adjacent semiconductor substrates supported by the boat or increase the time required for raising and lowering the temperature. In this case, productivity will be greatly reduced.

An object of the present invention is to solve the above problems, prevent thermal strain from occurring in the semiconductor substrate when the temperature of the semiconductor substrate is raised or lowered, and improve the productivity. Another object of the present invention is to provide a method for raising and lowering the temperature of a semiconductor substrate.

[0008]

In the semiconductor heat treatment apparatus according to the present invention, one end is opened and the other end is closed, and a process tube surrounded by a heater and a plurality of semiconductor substrates are vertically arranged. It is provided with a boat that is supported at intervals, moves up and down relative to the process tube, and can be inserted into the process tube when rising relative to the process tube. In a semiconductor heat treatment apparatus in which a cooling gas passage is formed in a portion between the heater and
Inside the process tube, there is a gas blowout part that extends in the vertical direction, and the same direction as the gas introduction pipe that introduces the in-plane temperature equalizing gas into the process tube when the semiconductor substrate is heated and cooled. And a gas discharge pipe for discharging the in-plane temperature-equalized gas of the semiconductor substrate introduced into the process tube, and the gas blow-out part and the gas suction part are provided in the process tube. It is arranged so as to sandwich the inserted boat, and a plurality of gas outlets are formed at intervals in the vertical direction at the gas outlet and a plurality of gas inlets are formed at intervals in the vertical direction at the gas inlet. Is formed and the temperature of the semiconductor substrate is raised by the heater.
When the temperature is lowered, the temperature- equalizing gas in the surface of the semiconductor substrate blown out from the gas outlet is sucked through the gas inlet through the space between the semiconductor substrates supported by the boat inserted in the process tube. It has been done.

According to the semiconductor heat treatment apparatus of the present invention, when the temperature of the semiconductor substrate is raised to the heat treatment temperature and when the temperature is lowered from the heat treatment temperature, the in-plane surface of the semiconductor substrate is opened from the gas outlet formed in the gas outlet of the gas inlet pipe. The temperature-equalizing gas can be blown out, and this gas can be sucked through the space between the semiconductor substrates supported by the boat from the gas suction port formed in the gas suction portion of the gas discharge pipe. Therefore, when the semiconductor substrate is heated to the heat treatment temperature and lowered from the heat treatment temperature, heat transfer in each semiconductor substrate is performed by convection in addition to heat conduction due to the function of the in-plane temperature equalizing gas of the semiconductor substrate. Therefore, the temperature difference between the peripheral portion and the central portion of each semiconductor substrate becomes smaller than that in the conventional case, and it is possible to prevent the occurrence of thermal strain due to thermal stress.
In particular, it is effective when the diameter of the semiconductor substrate is large. Moreover, since it is possible to prevent the occurrence of thermal strain due to the thermal stress of the semiconductor substrate when the temperature of the semiconductor substrate is raised or lowered, it is possible to reduce the distance between the adjacent semiconductor substrates supported by the boat as compared with the conventional case. In addition, the time required for raising and lowering the temperature can be shortened, and as a result, the productivity is improved.

In the above semiconductor heat treatment apparatus, a gas temperature homogenizing means for homogenizing the temperature of the gas which is located in the process tube and is blown out from each gas outlet in the upstream side of the gas outlet of the gas inlet pipe. It is preferable that the portion is provided. In this case, the temperature of the in-plane soaking gas of the semiconductor substrate supplied to the gas introduction pipe is made uniform while flowing through the gas temperature equalizing portion, so that the temperature of the gas blown out from each gas outlet becomes uniform. As a result, the temperatures of all semiconductor substrates can be made uniform. Therefore, the temperature rising / falling rates of all the semiconductor substrates can be made equal.

The gas temperature equalizing portion is, for example, a meandering portion having a plurality of straight pipe portions extending in the vertical direction.

A method of raising and lowering the temperature of a semiconductor substrate according to the present invention is a method of raising the temperature of a semiconductor substrate before heat treatment and lowering the temperature of a semiconductor substrate after heat treatment by using the apparatus according to claim 1, wherein the process is performed by a heater. Preheat temperature inside the tube
Preheat the semiconductor substrate in this state and support the semiconductor substrate in this state.
After inserting the boat into the process tube, blow out the temperature-equalizing gas in the plane of the semiconductor substrate from the gas outlet of the gas outlet of the gas inlet pipe, and pass this gas through the space between the semiconductor substrates supported by the boat. While sucking from the suction port, the temperature of the semiconductor substrate is raised to the heat treatment temperature by the heater,
After heat treatment, halfway from the gas outlet of the gas outlet of the gas inlet pipe.
Blow out the temperature-equalizing gas in the plane of the conductor substrate and use this gas in the boat.
Gas suction through supported semiconductor substrates
While sucking in from the mouth, between the process tube and the heater
Cooling gas is introduced into the cooling gas passage to cool the semiconductor substrate
It is characterized by performing.

According to the method for raising and lowering the temperature of the semiconductor substrate according to the present invention, when the temperature of the semiconductor substrate is raised to the heat treatment temperature and when the temperature is lowered from the heat treatment temperature, the in-plane temperature equalizing gas acts on each semiconductor substrate. In addition to heat conduction, heat transfer in the semiconductor is also performed by convection, and the temperature difference between the peripheral edge and the center of each semiconductor substrate becomes smaller than in the conventional case, causing thermal strain due to thermal stress. Can be prevented. In particular, it is effective when the diameter of the semiconductor substrate is large. Moreover, since it is possible to prevent the occurrence of thermal strain due to thermal stress of the semiconductor substrate when the temperature of the semiconductor substrate is raised or lowered,
As compared with the conventional case, the interval between the adjacent semiconductor substrates supported by the boat can be reduced, and the time required for raising and lowering the temperature can be shortened, and as a result, the productivity is improved.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
A description will be given with reference to the drawings.

1 and 2 show a semiconductor heat treatment apparatus, and FIG. 3 shows a gas introduction pipe.

1 and 2, a semiconductor heat treatment apparatus includes a vertical cylindrical heater (1) having a lower end opened and an upper end closed, and a vertical cylindrical heater (1) having an open lower end and an upper end closed and inside the heater (1). It supports the vertically arranged quartz vertical process tube (2) and a plurality of semiconductor substrates (3) (wafers) at intervals in the vertical direction, and can move up and down.
And a boat (4) that can be inserted into the process tube (2) in the raised position.

The peripheral wall of the heater (1) and the process tube (2)
A cooling gas passage (5) for flowing a cooling gas for lowering the temperature of the semiconductor substrate (3) after the heat treatment is formed in a portion between the cooling gas passage and the peripheral wall. The lower end of the process tube (2) projects slightly below the lower end of the heater (1). Although not shown, the process tube (2) is provided with an atmospheric gas inlet and an outlet for the same during the heat treatment.

Inside the process tube (2), there are two gas outlets (6) extending vertically, and the semiconductor substrate
Gas introduction pipe (7) for introducing temperature-equalizing gas in the plane of the semiconductor substrate into the process tube (2) during temperature rise and fall of (3)
And a gas discharge pipe (9) which also has a gas suction part (8) extending in the vertical direction and which discharges the in-plane temperature equalizing gas of the semiconductor substrate introduced into the process tube (2). There is.

As shown in FIG. 3, the gas introducing pipe (7) has two meandering pipes (10) having a plurality of straight pipe portions extending in the vertical direction, for example, six, and a central portion of the meandering pipe (10). It consists of a gas inlet pipe (23) connected to the bent part that connects the lower ends of the straight pipe parts, and along the peripheral wall of the process tube (2),
It is arcuate as a whole when viewed from a plane. Serpentine tube (10)
The lower end of is located below the lower end of the heater (1).
The two straight pipe parts located on the outermost side of the meandering pipe (10) of the gas introduction pipe (7) are made into the gas blowing part (6), and there are vertical intervals at each gas blowing part (6). Multiple Gas Outlets (11)
Are formed. The gas outlet (11) is located at the height between adjacent semiconductor substrates (3) supported by the boat (4) inserted in the process tube (2). . In addition, the gas inlet pipe (2) of the gas inlet pipe (7)
The tip of 3) penetrates the peripheral wall of the process tube (2) and extends to the outside thereof, and the tip opening serves as a gas inlet (12). And, the portion from the connection portion of the gas introduction pipe (7) with the gas inlet pipe (23) to the gas outlet pipe (6), that is, the meandering portion including the two straight pipe portions, , All gas outlets (1) of each gas outlet (6)
It is a gas temperature equalizing portion (13) for equalizing the temperature of the gas blown from 1).

The gas discharge pipe (9) is a straight pipe (14) extending in the vertical direction and a horizontal arc pipe (15) connected to the lower end of the straight pipe (14) and extending along the peripheral wall of the process tube (2). ) And an arc tube
It comprises a gas outlet pipe (16) connected to the tip of (15). The lower end of the straight pipe (14) is located below the lower end of the heater (1). The straight pipe (14) is the two gas outlets of the gas introduction pipe (7).
It is arranged so as to sandwich the boat (4) inserted in the process tube (2) together with (6), and this is the gas suction part.
(8). A plurality of gas suction ports (17) are formed in the gas suction section (8) at intervals in the vertical direction. The gas inlet (17) is located between adjacent semiconductor substrates (3) supported by the boat (4) inserted in the process tube (2), and the gas outlet (17). The semiconductor substrate in-plane temperature equalizing gas blown out from (11) is
It is designed to be sucked from the gas suction port (17) through the space (3). Also, the gas outlet pipe (16) of the gas discharge pipe (9)
The tip of the pierces through the peripheral wall of the process tube (2) and extends to the outside thereof, and the tip opening is used as a gas discharge port (18).

The boat (4) comprises a base (19) and a substrate support (20) provided on the base (19). The lower end of the base (19) is provided with a lid plate (21) that closes the lower end opening of the process tube (2) when the boat (4) is in the raised position. A motor (22) for rotating the boat (4) around a vertical axis is arranged below the cover plate (21).

The heat treatment of the semiconductor substrate (3) using the above-mentioned semiconductor heat treatment apparatus is performed as follows.

The boat (4) is lowered in advance and supports the semiconductor substrate (3) to be heat-treated. The inside of the process tube (2) is preheated to a predetermined temperature, for example 700 ° C., by the heater (1). Then, after raising the boat (4) and inserting it into the process tube (2), the heater
According to (1), the semiconductor substrate (3) is heated to a predetermined heat treatment temperature, for example, 1100 ° C. The temperature of the semiconductor substrate (3) is increased by forming an in-plane temperature equalizing gas introduced from the gas inlet (12), for example, nitrogen gas at room temperature, in the gas outlet (6) of the gas inlet pipe (7). From the gas outlet (11)
The semiconductor substrate (3) supporting this gas on the boat (4)
The gas is sucked from the gas suction port (17) formed in the gas suction part (8) of the gas discharge pipe (9) through the space (Fig. 2).
(See arrow). At this time, the boat (4) is rotated around the vertical axis by the motor (22).

When the temperature of the semiconductor substrate (3) reaches the heat treatment temperature, the blowing of the temperature-uniforming gas in the surface of the semiconductor substrate is stopped, and the temperature-uniforming gas in the surface of the semiconductor substrate inside the process tube (2) is sucked into the suction port ( If it is confirmed that the gas has been sucked in from the process tube (2) and discharged from the process tube (2), the desired atmospheric gas is introduced into the process tube (2) through the atmospheric gas inlet and kept at the heat treatment temperature for a predetermined time. Then, the semiconductor substrate (3) is heat-treated. Also at this time, the boat (4) is rotated around the vertical axis by the motor (22). In this case, all the semiconductor substrates (3) can be uniformly heat-treated.

When the heat treatment is completed, the atmospheric gas is discharged from the process tube (2) through the atmospheric gas discharge port to lower the temperature of the heater (1) and to cool the cooling gas passage (5).
A cooling gas is flown into the semiconductor substrate (3) to lower the temperature to the preheating temperature. The temperature of the semiconductor substrate (3) is lowered by the gas inlet (12).
A semiconductor substrate in-plane temperature-equalizing gas, such as nitrogen gas at room temperature, is blown out from the gas outlet (11) formed in the gas outlet (6) of the gas inlet pipe (7), and this gas is discharged from the boat.
The gas suction port (1) formed in the gas suction section (8) of the gas discharge pipe (9) is inserted between the semiconductor substrate (3) supported by (4).
While sucking from 7) (see arrow in Figure 2). Also at this time, the boat (4) is rotated around the vertical axis by the motor (22).

As described above, the temperature of the semiconductor substrate (3) is raised to the heat treatment temperature and the temperature of the semiconductor substrate (3) is lowered from the heat treatment temperature.
From the gas outlet (11) formed in the gas outlet (6) of (7), the temperature-equalizing gas in the plane of the semiconductor substrate is blown out, and this gas is used by the boat.
The gas suction port (1) formed in the gas suction section (8) of the gas discharge pipe (9) is inserted between the semiconductor substrate (3) supported by (4).
If it is performed while sucking in from 7), heat transfer in each semiconductor substrate (3) will be performed by convection in addition to heat conduction due to the action of the temperature-equalizing gas in the surface of the semiconductor substrate. The temperature difference between the peripheral part and the central part of (3) becomes small,
It is possible to prevent thermal strain due to thermal stress, and it is particularly effective when the diameter of the semiconductor substrate (3) is large. Moreover, when the temperature of the semiconductor substrate (3) is raised or lowered, the semiconductor substrate
Since it is possible to prevent the occurrence of thermal strain due to the thermal stress of (3), it is possible to reduce the distance between the adjacent semiconductor substrates (3) supported by the boat (4) and to raise and lower the temperature. The time can be shortened, resulting in improved productivity. Furthermore, when the boat (4) is rotated around the vertical axis by the motor (22) when the semiconductor substrate (3) is heated and lowered, the temperature difference between the peripheral portion and the central portion of each semiconductor substrate (3) is reduced. It becomes smaller, and the effects described above become more remarkable.

Further, the temperature of the temperature-equalizing gas in-plane of the semiconductor substrate supplied from the gas inlet (12) of the gas inlet pipe (7) is equalized while flowing through the gas temperature equalizing portion (13). The temperatures of the gas blown out from the gas outlets (11) are made uniform, and as a result, the temperatures of all the semiconductor substrates (3) can be made uniform. Therefore, all semiconductor substrates (3)
The temperature rising / falling rates of can be made equal.

In the above embodiment, the gas introduction pipe (7)
There are two gas outlets (6), but the gas outlet
The number of (6) is not limited to this, and can be changed as appropriate. Further, in the above embodiment, the gas exhaust pipe
Although one gas suction part (8) is provided in (9), the number of gas suction parts (8) is not limited to this, and can be appropriately changed. In the above embodiment, the gas outlet (11) formed in the gas outlet (6) of the gas inlet pipe (7).
Is located at the height between adjacent ones of the semiconductor substrates (3) supported by the boat (4) inserted in the process tube (2). The in-plane temperature equalizing gas blown from (11) is
Although it is designed to pass between the semiconductor substrates (3) supported by the boat (4) inserted in the process tube (2), the position of the gas outlet (11) is not limited to this. The position can be changed as appropriate as long as it is a position passing between the semiconductor substrates (3) supported by the boat (4) inserted in the process tube (2). For example, it may be formed at the same height as the semiconductor substrate (3). In this case, the in-plane temperature-equalizing gas blown from the gas outlet (11) hits the edge of the semiconductor substrate (3) and is divided into upper and lower parts to pass between the semiconductor substrates (3). Further, in the above embodiment, the portion of the gas introduction pipe (7) existing in the process tube (2) has a meandering shape as a whole, and the gas temperature uniformizing portion (13) also has a meandering shape, The shape is not limited to this, and the shape of the gas temperature equalizing portion (13) can be appropriately changed as long as it has a length capable of equalizing the gas temperature.

Further, in the above embodiment, the gas suction port (17) formed in the gas suction portion (8) of the gas discharge pipe (9).
Is located at a height between adjacent semiconductor substrates (3) supported by a boat (4) inserted in the process tube (2), but the gas inlet ( 17)
The position of the gas introduction pipe is not limited to this.
The position can be appropriately changed as long as it is a position where the gas blown out from the gas outlet (11) formed in the gas outlet (6) of (7) can be sucked in.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a semiconductor heat treatment apparatus according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a front view of a gas introduction pipe.

[Explanation of symbols]

(1): Heater (2): Process tube (3): Semiconductor substrate (4): Boat (5): Cooling gas passage (6): Gas outlet (7): Gas inlet pipe (8): Gas suction part (9): Gas exhaust pipe (11): Gas outlet (17): Gas inlet

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-263369 (JP, A) JP-A-4-329631 (JP, A) JP-A-3-235329 (JP, A) JP-A-3- 209817 (JP, A) JP-A-4-245421 (JP, A) JP-A-6-196428 (JP, A) Fukukaihei 3-10272 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/26-21/268 H01L 21/322-21/326 H01L 21/205 H01L 21/22-21/24

Claims (4)

(57) [Claims] 1. A process tube which is open at one end and closed at the other end and which is surrounded by a heater, supports a plurality of semiconductor substrates at intervals in the vertical direction, and relatively supports the process tube. It has a boat that moves up and down and can be inserted into the process tube when it rises relative to the process tube,
In a semiconductor heat treatment apparatus in which a cooling gas passage is formed between a process tube and a heater, a gas blowout portion extending in the vertical direction is provided inside the process tube, and when the semiconductor substrate is heated or cooled. It has a gas inlet pipe that introduces the temperature-equalizing gas in the surface of the semiconductor substrate into the process tube and a gas suction part that also extends vertically, and discharges the temperature-equalizing gas in the surface of the semiconductor substrate that has been introduced into the process tube. A gas discharge pipe is provided, and the gas blow-out portion and the gas suction portion are arranged so as to sandwich the boat inserted in the process tube. The air outlet is formed and a plurality of gas inlets are formed in the gas inlet at intervals in the vertical direction, and the temperature of the semiconductor substrate is raised by the heater when it is heated.
When the temperature is lowered, the temperature- equalizing gas in the surface of the semiconductor substrate blown out from the gas outlet is sucked through the gas inlet through the space between the semiconductor substrates supported by the boat inserted in the process tube. Semiconductor heat treatment equipment that is made. 2. A gas temperature equalizing portion, which is located in the process tube and which equalizes the temperature of the gas blown out from each gas outlet, is provided at a portion upstream of the gas outlet in the gas inlet pipe. The semiconductor heat treatment apparatus according to claim 1. 3. The semiconductor heat treatment apparatus according to claim 2, wherein the gas temperature equalizing portion is a meandering portion having a plurality of straight pipe portions extending in the vertical direction. 4. A method of raising the temperature of a semiconductor substrate before heat treatment and lowering the temperature of a semiconductor substrate after heat treatment using the apparatus according to claim 1, wherein the inside of the process tube is preheated to a preheat temperature by a heater.
Keep the boat supporting the semiconductor substrate in this state.
After inserting into the process tube, blow out the in-plane temperature equalizing gas of the semiconductor substrate from the gas outlet of the gas outlet of the gas inlet pipe, and pass this gas through the space between the semiconductor substrates supported by the boat from the gas inlet. To the heater while sucking
The temperature of the semiconductor substrate is further raised to the heat treatment temperature, and after the heat treatment,
From the gas outlet of the gas outlet of the gas inlet pipe to the surface of the semiconductor substrate
The soaking gas is blown out and this gas is supported by the boat.
Suction from the gas inlet through the space between the semiconductor substrates
The cooling gas flow between the process tube and the heater.
A method for raising and lowering the temperature of a semiconductor substrate, which comprises introducing a cooling gas into the passage to lower the temperature of the semiconductor substrate.