JPH02174224A - Heat treatment device - Google Patents

Abstract

PURPOSE:To prevent the emergence of dust in the introduction process of a treated gas and improve a yielding rate by introducing at least into one introduction pipe independently a plurality of different sorts of respective reaction gases and flowing a plurality of these reaction gases into a reaction vessel after mixing these gases in the process of flowing in the introduction pipe. CONSTITUTION:A plurality of L-shaped source gas introduction pipes 10-12 are installed at the lower end outside circumference of a reaction vessel 1 by causing respective gas discharge parts to protrude in an internal cylinder 3. Further, an SiH2Cl2 gas introduction pipe 11 which is used for the introduction of reaction gases, e.g. the SiH2Cl2 gas, an NH3 gas introduction pipe 12 which is used for the introduction of the NH3 gas, and a gas mixing introduction pipe 10 through which SiH2Cl2 and NH3 gases are introduced separately and are discharged after mixing the above gases in the process of flowing in respective pipes are installed all in one plane. An N2 gas introduction pipe 13 which is used for introduction of inactive gases, e.g. the N2 gas into the reaction vessel 1 with the completion of treatment is installed after inserting the gas discharge part into a gap between internal and external cylinders. Even in the case where treatment is performed at uniform temperature conditions, uniform and high quality films are formed; besides, emergence of dust is prevented in the introduction process of a treated gas and yielding rate is improved.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a heat treatment apparatus.

(Conventional technology) In recent years, heat treatment equipment used in the thermal diffusion process and film formation process in the semiconductor device manufacturing process has been developed to save space, save energy, increase the diameter of semiconductor wafers to be processed, and increase automation. Vertical heat treatment equipment has been developed because it is compatible with containers and other reasons.

In such a vertical heat treatment apparatus, the reactor body, which is composed of a cylindrical reaction vessel made of quartz or the like, a heater, a soaking tube, a heat insulating material, etc. installed around the vessel, is arranged almost vertically. In this system, a large number of semiconductor wafers are stacked on shelves at predetermined intervals on a wafer boat made of quartz or the like, and the semiconductor wafers are loaded and unloaded from below inside the reaction vessel using a transport mechanism that can move up and down, for example. It is composed of

By the way, in processing using such a vertical heat processing apparatus, in order to make the quality of the thin film formed on each semiconductor wafer uniform, the processing temperature in the reaction vessel is maintained uniformly, and a predetermined reaction gas is Processing is carried out by introducing the gas through a predetermined gas introduction part of the reaction vessel, for example, a gas introduction pipe provided below the reaction vessel.

(Problem to be Solved by the Invention) However, in the conventional vertical heat treatment apparatus described above, the concentration of the reaction component in the reaction gas decreases as the distance from the reaction gas introduction part increases. The amount of film formed on semiconductor wafers placed in the upper part of the reaction vessel, that is, semiconductor wafers placed in the upper part of the reaction vessel, is smaller than that on semiconductor wafers placed near the reaction gas introduction part, that is, semiconductor wafers placed in the lower part of the reaction vessel, and uniform film formation is not achieved. The problem was that I couldn't do it.

Furthermore, the reaction gas may cause dust to be generated during the flow process, and at temperatures below 120 to 130°C, N114CI particles, which are side reaction products, are precipitated, and these polysilicon particles and N)1.01 There is a problem in that the particles become dust in the reaction container together with the reaction gas and are scattered and adhere to the group of semiconductor wafers, causing a decrease in yield.

The present invention has been made to solve the above-mentioned problems, and enables uniform and high-quality film formation even during processing under uniform temperature conditions, and further improves yield by preventing the generation of dust during the process of introducing processing gases. The object of the present invention is to provide a heat treatment apparatus that can be improved.

[Structure of the Invention] (Means for Solving the Problems) The heat treatment apparatus of the present invention includes a reaction vessel for accommodating objects to be treated arranged at predetermined intervals, and a predetermined reaction gas introduced into the reaction vessel. In a heat treatment apparatus equipped with a plurality of reaction gas introduction pipes arranged as described above, a plurality of different reaction gases are independently introduced into at least one of the plurality of reaction gas introduction pipes, and a plurality of reaction gases are independently introduced into the plurality of reaction gas introduction pipes. The present invention is characterized in that the gases are mixed during the flow process in the introduction pipe and flowed into the reaction vessel.

In addition, the position of the gas mixing part in the introduction tube for mixing the reaction gases is located in a temperature range where the introduced multiple types of reaction gases do not react and generate dust, thereby preventing the generation of dust during the process of introducing the processing gas. It may be configured to prevent this.

(Function) The heat treatment apparatus of the present invention independently introduces a plurality of different reaction gases into at least one of the plurality of reaction gas introduction tubes, and flows these plurality of reaction gases through the introduction tube. By providing a gas mixing inlet tube that mixes and discharges the gas into the reaction vessel, uniform and high-quality film formation can be performed even during processing under uniform temperature conditions. By locating the part in a predetermined temperature range within the reaction vessel, it is possible to prevent the generation of dust during the process of introducing the processing gas and to improve the yield.

(Example) Hereinafter, an example in which the present invention is applied to a vertical heat treatment apparatus for forming a nitride film will be described with reference to the drawings.

The reaction vessel 1 is composed of an outer cylinder 2 made of, for example, quartz and having an inner diameter of 240 mm, and an inner cylinder 3 made of, for example, quartz and having an inner diameter of 20 ha and a length of 111, which is housed concentrically and spaced apart within the outer cylinder 2. It has a double-tube structure. A heater 4 and a heat insulating material 5 are disposed to surround the reaction vessel 1.

The lower end of the reaction vessel 1 is sealed with a disc-shaped flange 6 made of stainless steel or the like.
A heat insulating cylinder 7 is inserted above to maintain a predetermined gap with the inner cylinder 3 and insulate the heat inside the reaction vessel 1 . A wafer boat 9 made of quartz, for example, in which a large number of semiconductor wafers 8 are arranged and housed at predetermined intervals is mounted on the heat-insulating tube 7 . For example, 100 semiconductor wafers are transferred from a wafer carrier to this wafer boat 9 by a wafer transfer device, and the wafers are automatically transferred onto the heat-insulating cylinder 7 by the boat carrier. The wafer boat 9 and the heat insulating cylinder 7 are configured to be loaded and unloaded by a lifting mechanism (not shown), such as a boat elevator.

In addition, a plurality of L-shaped source gas introduction pipes 10, 11, 12 are provided on the outer circumferential wall of the lower end of the reaction vessel 1, with their respective gas discharge portions protruding into the inner cylinder 3. 5 for introducing gas e.g. 5ill 2 C12 gas
ill 2 CI2 gas introduction pipe 11, NH3 gas introduction pipe 12 for introducing N113 gas, gas mixing introduction pipe 1 for introducing SIH2C12 gas and NH3 gas individually and mixing and discharging them during the gas distribution process.
0 are provided on the same plane, and an N2 gas introduction pipe 13 for introducing an inert gas, such as N2 gas, into the reaction vessel 1 after the completion of the treatment connects its gas discharge portion to the inner cylinder 3 and the outer cylinder 2. It is inserted into the gap between the

The processing gases introduced into the reaction volume "ri1" through these source gas introduction pipes 10, 11, 12 are discharged from the exhaust pipe 14 to a vacuum pump (not shown).

A more detailed structure of each of the source gas introduction pipes 10, 11, 12 described above will be described below with reference to FIGS. 3 and 4.

As shown in FIG. 3, the gas mixing introduction pipe 10 is an L-shaped pipe made of, for example, a quartz member, and has an inner diameter of, for example, 4 mm, and the lower part of the vertical part V of the introduction pipe inserted into the inner cylinder 3 is Y-shaped. It has a bifurcated shape and is connected to the horizontal part H of the introduction pipe, forming two gas introduction bows 1m1 and 1m2. The source gas from each of these gas introduction boats m1 and m2 is, for example, 5ill 2 CI2 from the gas introduction boat m1.
After the gas and N113 gas are introduced from the gas introduction bow hm2 and mixed at the merging part 10a, they are placed on the side wall of the vertical part V of the introduction pipe at a predetermined pitch, for example, 50 to 15 (1 m
The gas is discharged from a plurality of gas discharge holes drilled at a pitch of o+, for example, gas discharge ports 10b having a diameter of 0.7w+m.

The height of the vertical portion V of this gas mixing introduction pipe 10 is:
It extends to a height between the top of the group of semiconductor wafers 8 housed in the wafer boat 9 and the path, and in this embodiment, the length of the vertical portion V of the introduction tube is approximately 1060+u+.

Further, the gas discharge holes 10b are bored at a portion facing from the middle to the upper side of the group of semiconductor wafers 8 housed in the wafer boat 9, and the pitch of the holes increases from sparse to dense in the upward direction. It is formed like this. These drilling pitches are appropriately selected depending on usage, processing details, and processing atmosphere.

Furthermore, the gas confluence part 10 of the gas mixing introduction pipe 10
The position a is located at a temperature below the temperature at which SIH2CI2 gas thermally decomposes in the reaction vessel 1 and reacts with NH3 to form NH,
Temperature range above the temperature at which CI is generated, e.g. 300-4
In this embodiment, since this temperature region corresponds to the lower side surface of the heat-insulating cylinder 7 in the reaction vessel 1, the horizontal part H of the inlet pipe is arranged to correspond to this position. The gas confluence section 10 of the inlet pipe is located approximately 45 m5 from the
A was set up.

On the other hand, 5il for introducing 51112 C12 gas
As shown in FIG. 4, the l 2 CI2 gas introduction pipe 11 is an L-shaped pipe made of, for example, a quartz member, and has a gas introduction boat n formed in the horizontal portion H thereof. The Si82 C12 gas introduced from the gas introduction boat n is discharged from the gas discharge hole 11a at the tip of the vertical portion V of the introduction tube inserted into the inner cylinder 3.

The position of the gas discharge hole 11a in the vertical part V of this SIH2CI2 gas introduction pipe 11 is
C12 gas is thermally decomposed. For example, the temperature range is set in a temperature range of 300 to 400°C, which is below the temperature and above the temperature at which NH and CI are generated by reacting with NH3. Since this position corresponds to the lower side surface of the cylinder 7, the tip of the vertical part of the gas introduction pipe 11 was extended to a position approximately 45 a+m from the horizontal part H of the introduction pipe so as to correspond to this position.

In addition, the 113 gas introduction pipe 12 for introducing the Nll3 gas is provided at a predetermined angle θ, for example, 45 degrees or more, from the SIH2C12 gas introduction pipe, and the SiH2C12 gas introduction pipe shown in FIG. Like the tube 11, it is an L-shaped tube made of, for example, a quartz member, and its horizontal portion H
A gas introduction boat n is formed at. NH3 gas is introduced from this gas introduction boat n and is discharged from the gas discharge hole 12a at the tip of the vertical portion V of the introduction tube inserted into the inner cylinder. The position of the gas discharge hole 12a in the vertical part V of the N113 gas introduction pipe 12 is provided in a low temperature region, and in this embodiment, the lower side of the heat insulating tube 7 in the reaction vessel 1 is at the lowest temperature. The height of the vertical portion V was set to approximately 1 Ofl111 to correspond to the position.

Further, the N2 gas introduction pipe for introducing N2 gas is an L-shaped pipe made of, for example, a quartz member, similar to the SIH2CI2 gas introduction pipe 11 shown in FIG.
A gas introduction boat n is formed at. N2 gas is introduced from this gas introduction port n, and the gas discharge hole 13a at the tip of the vertical part V of the introduction pipe inserted into the gap between the inner cylinder 3 and the outer cylinder 2
It is discharged from.

Gas discharge hole 13 at the tip of the vertical part of this N2 gas introduction pipe 13
The position a is preferably located as far away from the heat insulating cylinder 7 as possible, and is preferably a portion where no Si3N4 film is formed on the inner cylinder wall or outer cylinder wall. The reason for this is that the temperature of the inner cylinder wall and outer cylinder wall near the heat insulation cylinder 7 is low, so an NH4C1 film is easily formed, and when N2 gas is introduced, this NH4C1 film is rolled up, causing dust generation. Further, even if a Si3N4 film is formed on the inner cylinder wall or the outer cylinder wall, this Si3N4 film will similarly be rolled up, causing dust generation.

In this example, the length of the vertical portion V of the N2 gas introduction pipe 13 is approximately 12 hm, and the gas discharge hole 13a at the tip of the vertical portion is set at a height such as between the center portion of the heat-insulating cylinder and the gap.

The operation of the vertical heat treatment apparatus having such a configuration is as follows: First, a wafer boat 9 containing a group of semiconductor wafers 8 is inserted into the inner cylinder 3 using a boat elevator (not shown), and then the inside of the reaction vessel 1 is set to a predetermined vacuum. N1 from each source gas inlet pipe 10, 11.12 while maintaining the temperature at, for example, 0.17 Torr.
! 3 gas and Sl! l 2 C12 gas treatment is introduced, and the semiconductor wafer group 8 is heated to a predetermined treatment temperature, for example, 700 to 850° C., by the heater mechanism 4 to form a nitride film. At this time, temperature control is performed so that the entire reaction vessel 1, that is, the entire semiconductor wafer group 8, is kept at a constant temperature.

The flow of each processing gas during processing is as shown in FIG.
2 C12 gas introduction pipe 11 and N113 gas introduction pipe 1
2 are Si22 from the bottom of semiconductor group 8, respectively.
Discharge CI2 gas g2 and NH3N3 gas.

By discharging the source gas to the semiconductor wafers from both above and below the group 8, the gas concentration in the reaction vessel 1 is made uniform, so that each semiconductor wafer 8 is discharged under uniform temperature conditions.
It is possible to form a film with excellent uniformity on each semiconductor wafer 8 and on each semiconductor wafer 8.

Furthermore, since each semiconductor wafer 8 is processed under the same temperature conditions, the film quality between each semiconductor wafer 8 becomes equal.

By the way, 5ill 2 CI2 gas is thermally decomposed at a temperature of about 400° C. or higher under reduced pressure, for example, 0.1 Torr, and polysilicon particles are generated. Also, 120-13
At temperatures below 0℃, it reacts with NH3 gas to form NH4C1.
Particles are generated. These polysilicon particles and N
The H4C1 particles scatter as dust in the reaction vessel 1 together with the source gas and adhere to the semiconductor wafer group 8, causing a decrease in yield, but in this example, 5ill 2
The positions of the gas discharge holes 11a and 12a of the C12 gas introduction pipe 11 and the NH3 gas introduction pipe 12 are set at 300 to 300 in the reaction vessel 1.
Since it is set in a temperature region of 400° C., that is, in a position corresponding to the lower side surface of the heat retaining cylinder 7, generation of such dust can be prevented.

Moreover, the gas discharge hole 10b of the gas mixing introduction pipe 10
Since it is set above the reaction vessel 1, it is under a high temperature atmosphere similar to the processing temperature, for example, 780°C, but the discharged gas g1 is in the temperature range of 300 to 400°C inside the reaction vessel 1. Since the gases are mixed in advance at the gas merging section 10a of the inlet pipe 10, S is already mixed at the gas discharge section 10b.
It is in i3N4 state and there is no problem of dust caused by polysilicon particles.

After completing the film forming process in this way, while purging N2 gas into the reaction vessel 1 from the N2 gas introduction pipe 13, the boat elevator (not shown) is lowered, the wafer boat 9 is taken out of the reaction vessel 1, and the film is formed. The work is finished.

The shape of the gas mixing introduction pipe 10 used in the present invention is not limited to the shape shown in FIG. 3, for example, as shown in FIG. It may be of any shape as long as the processing gas from each gas introduction port ml, m2 is uniformly mixed at the confluence portion 10a.

[Effects of the Invention] As explained above, according to the vertical heat treatment apparatus of the present invention, it is possible to prevent the generation of dust during the process of introducing the processing gas, thereby improving the yield. Moreover, it becomes possible to form a film of high quality.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of the vertical heat treatment apparatus of the embodiment, Fig. 2 is a bottom plan view of Fig. 1, Fig. 3 is a diagram showing the gas mixing inlet pipe of the embodiment, and Fig. 4. 5 is a diagram showing the source gas introduction pipe of the embodiment, FIG. 5 is a diagram showing the flow of the source gas of the embodiment, and FIG. 6 is a diagram showing an example of another shape of the gas mixing introduction pipe. 1...Reaction container, 2...Outer cylinder, 3...
... Inner cylinder, 4 ... Heater mechanism, 7 ...
...Heat insulation tube, 8...Semiconductor wafer group, 9...
...Wafer boat, 10...Introduction pipe for gas mixing, 11...Introduction pipe for 5ill 2 C12, 12...Introduction pipe for NI+3 gas, 13...
...Introduction pipe for N2 gas.

Claims (1)

[Claims] A heat treatment apparatus comprising a reaction vessel containing objects to be treated arranged at predetermined intervals, and a plurality of reaction gas introduction pipes provided to introduce a predetermined reaction gas into the reaction vessel. In this step, a plurality of different types of reaction gases are independently introduced into at least one of the plurality of reaction gas introduction pipes, and these plurality of reaction gases are mixed during a flow process in the introduction pipe, and are then introduced into the reaction vessel. A heat treatment apparatus characterized in that the heat treatment apparatus is configured such that the flow of water flows into the heat treatment apparatus.