JP3159726B2 - Heat treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus, and more particularly to an improvement in the structure of a heat treatment apparatus for performing a heat treatment by introducing a process gas into a reaction tube for accommodating an object to be treated.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process of a semiconductor wafer or the like, an object to be processed such as a semiconductor wafer is housed in a reaction tube and subjected to a heat treatment in order to perform various processes such as CVD, oxidation and diffusion on the semiconductor wafer. A heat treatment apparatus is used.

FIG. 5 is a schematic diagram showing an example of such a conventional heat treatment apparatus.

In the figure, a reaction tube 10 is made of quartz SiO _2.
, And a gas inlet pipe 12 and a gas outlet pipe 14 are formed at lower positions thereof. The gas introduction tube 12 is formed so as to communicate the outside and the inside of the reaction tube 10, and a tip portion in the gas introduction tube 12 extends to an upper position in the reaction tube 10. On the other hand, the gas discharge pipe 14 is formed by projecting a pipe from a lower position of the reaction pipe 10.

[0005] Inside the reaction tube 10, semiconductor wafers 18 stacked and installed at predetermined intervals on a boat 16 are stored. The boat 16 on which the semiconductor wafers 18 are installed is installed on a heat retaining tube 20. In addition, heat insulation cylinder 2
0 is moved up and down by an elevating mechanism 22 disposed therebelow, and the semiconductor wafer is moved up and down by the vertical movement of the reaction tube 10.
It can be stored or taken out. The reaction tube 10 is completely sealed in a state where the heat retaining cylinder 20 is raised by the elevating mechanism 22 and the semiconductor wafer 18 is completely housed in the reaction tube 10.

[0006] A heating means 27 comprising a heating element 24 and a heat insulating material 26 is arranged in an external region of the reaction tube 10. The heating element 24 is attached to the inner peripheral wall of the heat insulating material 26.

With such a configuration, a process gas is introduced into the reaction tube 10 from the gas introduction tube 12, and the inside of the reaction tube 10 is heated to a predetermined temperature (for example, 1200 ° C.) by the heating action of the heating element 24. The semiconductor wafer 18 is subjected to a heat treatment by a reaction of a process gas under heating.

[0008]

In the above-mentioned conventional heat treatment apparatus, the reaction tube 10 is formed of quartz SiO _{2 which} emits little impurities during heat treatment.

However, there has been a problem that the reaction tube 10 formed of SiO ₂ may be deformed when heated at a high temperature (about 1200 ° C.) for a long time. Therefore, it is conceivable to form the reaction tube 10 with silicon carbide SiC which has better heat resistance and is less likely to be deformed by heat. According to the reaction tube made of SiC, it is possible to solve the problem of deformation by heat. it can.

However, when the entirety of the reaction tube 10 is formed of SiC, the gas introduction tube 12 and the gas discharge tube 14
However, there is a problem that it is difficult to manufacture a relatively complicated component such as a portion. Further, SiC is
The thermal conductivity is at least 10 times higher than iO _2,
When the whole is made of SiC, heat radiation from the lower region side of the reaction tube 10 not covered with the heat insulating material 26 is large. Therefore, there is a problem in that the portion in which the semiconductor wafer 18 is housed is also affected by the heat radiation, and the heat uniformity of the region may be impaired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to reduce the possibility of thermal deformation even in a high-temperature state, and to ensure uniformity of the storage area of the object to be processed. It can be to provide a heat treatment apparatus which can be processed relatively easily to further.

[0012]

According to a first aspect of the present invention, there is provided a heat treatment apparatus, comprising: a reaction tube for heat-treating an object to be processed; and a process gas penetrating from outside the reaction tube to the inside of the reaction tube. A gas introducing pipe for feeding the gas into the reaction tube, wherein the gas introducing pipe is attached to and detached from a penetrating portion penetrating a lower side wall of the reaction tube and a tip end of the penetrating portion projecting a predetermined length into the reaction tube. freely mounted, the reaction tube extension portion extending to the upper position of the reaction tube in the mounted state, is composed of stone penetration portion of the gas inlet tube
The extension in the reaction tube is made of SiC.
Characterized in that was.

[0013]

[0014] The heat treatment apparatus according to the second aspect of the present invention further includes a buffer plate, which is installed substantially horizontally at a position slightly below the ceiling of the reaction tube and has a plurality of openings,
The uppermost end of the in-reaction tube extension penetrates the buffer plate. The heat treatment apparatus according to claim 3 , further comprising a heating device arranged around the reaction tube, wherein the reaction tube is a first component part which is at least a region surrounded by the heating device, and The first component is formed of SiC, and the second component is formed of quartz. Heat treatment apparatus according to the invention of claim 4 is characterized in that a groove having an exhaust port at the junction of the first component and the second component constituting the reaction tube.

[0015]

According to the first aspect of the present invention, the gas is contained in the reaction tube.
The gas introduction pipe for feeding the gas
It is composed of two parts, a long part and a long part. And, in the reactor
The long part is detachable at the tip of the penetration part inside the reactor,
Only the extension inside the reaction tube can be removed from the reaction tube
is there. Therefore, other members such as the object to be processed are removed from the reaction tube.
Out of the reaction tube of the gas introduction tube.
Can be removed. This allows the gas inlet
To easily remove the reaction products attached to the surface
And cleaning can be completed. Also the reaction
Easy replacement of the extension inside the tube
It is also possible to change the configuration of the
You. For example, a gas delivery opening on the side wall of the extension of the gas inlet pipe
When forming an opening, the configuration of the opening is
Various changes can be made in accordance with the software.

Further , according to the present invention , the heat treatment function can be improved by forming the penetrating portion with quartz and the extending portion in the reaction tube with SiC. That is, by forming the extension portion in the reaction tube located near the object to be processed using SiC having better heat resistance than quartz (SiO ₂ ), even when the high heat state of about 1200 ° C. continues for a long time. There is no risk of deformation or the like, and the reliability of the device is improved.

According to the second aspect of the present invention, the process gas introduced from the gas introduction tube is introduced between the buffer plate and the ceiling of the reaction tube. Therefore, the process gas is dispersed from the plurality of openings of the buffer plate, enters the reaction tube and fills up, and can promote uniform process gas distribution.

According to the third aspect of the present invention, the reaction tube is composed of two members, and at least one of the first components, which is a region surrounded by the heating device, is formed of SiC,
The component is formed of quartz. Since SiC is a member having much higher thermal conductivity than quartz, heat transfer from the heating device to the first component of the reaction tube is improved. In addition, since the second component made of quartz having lower thermal conductivity than SiC is prevented from becoming as high in heat as the first component,
The release of heat from the components is suppressed, thereby improving the uniformity of heat in the storage area of the object to be processed. As a result, the effect of the heat treatment on the object can be equalized. Even in the case where heat treatment is performed at a predetermined high temperature for a long time, in the case of SiC, since there is little risk of thermal deformation, the reliability of the device is improved. Furthermore, the second
Since the constituent parts are formed of quartz (SiO ₂ ), it is possible to form the attachment parts of the gas introduction pipe and the gas discharge pipe, which are relatively complicated, with quartz having better workability than SiC or the like. Therefore, it can be manufactured relatively easily. According to the fourth aspect of the present invention, since the joint between the first component and the second component can be sealed and evacuated, the joining between the two components that are in a high temperature state during the heat treatment is high. Airtightness can be maintained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a vertical heat treatment apparatus for performing a diffusion process on a semiconductor wafer is used as an example.

FIG. 1 is a schematic sectional view showing the overall configuration of a heat treatment apparatus according to an embodiment. Elements similar to those of the conventional apparatus of FIG. 5 are denoted by the same reference numerals.

In the figure, a reaction tube 10 is a first component 10
a and the second component 10b. The first component 10a is made of a heat-resistant material such as SiC, which is a good heat-conductive member, and the second component 10b is made of quartz (SiO ₂ ), which is a heat-resistant member. The first component part is an outer region surrounding the storage part in a state where the semiconductor wafer 18 is stored.

The gas introduction pipe 12 and the gas discharge pipe 14
Are attached to the second component 10b of the reaction tube 10, respectively, and FIG. 2 is an explanatory view showing their attachment positions. As shown in the figure, a gas discharge pipe 14 is provided at an angle of approximately 90 ° with respect to the gas inlet pipe 12, and the inside and outside of the reaction tube 10 are in communication with each other.

In the schematic cross-sectional view of FIG. 1, the position of the gas introduction pipe 12 is shifted by approximately 90 ° for convenience of explanation.

As shown in FIG. 1, in the present embodiment, the gas introduction pipe 12 is connected to the second component 1 of the reaction tube.
0b and the reaction tube 1
0, it has a two-body configuration of an extending portion 12b extending upward. As for the material of the gas introduction tube 12 composed of the two members, the extension portion 12b is made of SiC having high heat resistance, and the attachment portion 12a is made of quartz having good workability similarly to the reaction tube 10. are doing.

The uppermost end of the extending portion 12b of the gas introduction pipe 12 passes through the buffer plate 30. This buffer plate 3
Numeral 0 is horizontally installed at a position slightly below the ceiling of the reaction tube 10, has a planar shape as shown in FIG. 3, and has a plurality of openings 32. That is,
The process gas introduced from the gas introduction tube 12 is introduced between the buffer plate 30 and the ceiling of the reaction tube 10. Here, the process gas penetrates downward through the opening 32 of the buffer plate 30 and is dispersed to fill the inside of the reaction tube 10.

Next, the first component 10a and the second
The configuration of the joint of the component 10b will be described.

As shown in FIG. 1, both components 10
A groove 34 is formed at the junction between a and 10b. The groove 34 is formed by forming a continuous concave portion on the joint surface of the second component 10b with the first component 10a. The seal exhaust pipe is drawn out of the groove 34 closed by the joining of the first component 10a, and is constantly exhausted by an exhaust device (not shown).

FIG. 4 shows the state of attachment of the seal exhaust pipe 36.
Is shown in FIG. 4 is a partially cut-away horizontal sectional view showing a state of attachment of the seal exhaust pipe, in which a communication port 36 a of the seal exhaust pipe 36 communicates with the groove 34.

In this embodiment, the joint between the lid 38 on which the heat insulating tube 20 is placed (see FIG. 1) and the second component 10b of the reaction tube joined to this lid is also provided. A seal exhaust means is formed. That is, the groove 40 is formed in the lower joint surface of the second component 10 b, and the groove 40 is closed by joining with the lid 38, and the seal exhaust pipe 42 is drawn out from the groove 40. ing. FIG. 1 shows a seal exhaust pipe 42,
Since the seal exhaust pipe 36 is located behind the seal exhaust pipe 42, it is not shown.

As described above, in the present embodiment, the grooves 34 and 40 are formed at both the upper and lower joints of the second component 10b of the reaction tube. The seal exhaust pipes 36 and 42 have been drawn out as shown. In the figure, a communication port 42a (see FIG. 4) of the seal exhaust pipe 42 communicates with the groove 40.

According to the heat treatment apparatus having the above structure, the reaction tube is a region surrounded by a heating device (not shown), that is, a portion surrounding the region in which the semiconductor wafer 18 to be processed is stored. Since the first component 10a is formed of SiC, when heating by the heating unit 27 is started,
Since the first component 10a has a high thermal conductivity, the temperature quickly rises to a high level, and the whole of the first component 10a is in a uniform temperature state. As a result, the heating action on each semiconductor wafer 18 becomes substantially uniform, and a uniform heat treatment can be performed.

Further, since SiC has a low deformability even in a high temperature state, there is no possibility that a trouble due to thermal deformation of the reaction tube 10 occurs.

Further, a gas introduction pipe 12 and a gas discharge pipe 14 are attached to the second component 10b, and in this embodiment, the seal exhaust pipes 36 and 42 are attached. It has become. However, since the second component 10b is formed of quartz, its workability is relatively good, and there is no danger that the work will be difficult. Further, since the heat transfer coefficient of quartz is inferior to that of SiC, heat radiation from the lower end opening side of the reaction tube 10 can be reduced, and the temperature control using the wafer accommodating zone as the soaking zone becomes easy.

Further, the first component 10a and the second component 1
0b is connected to the groove 34 formed at the joint between the two.
By using the seal exhaust pipe 36 to create a negative pressure.
The lower end of the first component 10a can be adsorbed to the upper end of the second component 10b, and the airtightness can be ensured by eliminating the gap between the two. Further, even if a gap is formed, gas that has entered the gap can be exhausted, so that leakage of gas to the outside can be prevented. Further, in the present embodiment, the groove 40 and the seal exhaust pipe 4 are also formed at the joint between the second component 10b and the lid 38 which is the bottom thereof.
2 are provided. Accordingly, by performing vacuum evacuation using the seal exhaust pipe 42, complete airtightness is similarly secured on the lower side of the second component 10b. This not only prevents the airtightness from being deteriorated due to the formation of the two reaction tubes 10, but also ensures a higher airtightness than before in the entire apparatus.

In this embodiment, since the gas introduction pipe 12 is composed of two parts, the extension 12b of the gas introduction pipe 12 can be easily removed at the time of cleaning or the like.
That is, since the joint between the extension portion 12b and the attachment portion 12a is both inside the reaction tube 10, there is no problem even if there is some leakage, and the structure is such that it is simply rubbed, so that attachment and detachment is extremely easy. It is. By this removal and cleaning, it is possible to easily remove dirt due to the adhesion of the reaction product to the gas introduction tube 12.

[0036]

According to the first aspect of the present invention, the extension in the reaction tube is performed.
The extended part of the long gas introduction pipe can be easily attached and detached.
Therefore, it is easier and more thorough to clean the extension.
The extension can be installed in various configurations.
Gas supply that can be changed
It becomes possible to perform piping for irrigation.

Further, according to the present invention, the extension portion in the reaction tube located near the object to be processed is formed of SiC having higher heat resistance than quartz, so that a high heat state of about 1200 ° C. can be maintained for a long time. There is no danger of deformation or the like even in the subsequent case, and the reliability of the device is improved. According to the second aspect of the present invention, the process gas is dispersed from the plurality of openings of the buffer plate and enters the reaction tube to be filled, thereby facilitating uniformization of the process gas distribution. Claim 3
According to the invention of (1), it is possible to effectively prevent the deformation of the reaction tube in a high temperature state, to ensure the uniformity of the temperature of the heated portion of the object to be processed, and to cause difficulty in processing at the portion where various tubes are attached. Not even. According to the fourth aspect of the present invention, the joint between the first and second components can be sealed and evacuated, and the high airtightness of the junction between the two components that becomes high during the heat treatment can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing the entire configuration of an embodiment.

FIG. 2 is an explanatory view showing an installation state of a gas introduction pipe and a gas discharge pipe of the embodiment.

FIG. 3 is a plan view of a buffer plate according to the embodiment.

FIG. 4 is a partially cutaway sectional view showing an installation state of a seal exhaust pipe of the embodiment.

FIG. 5 is a schematic sectional view showing an example of a conventional heat treatment apparatus.

[Explanation of symbols]

10 reaction tubes 10a first component 10b second component part 12 a gas introduction pipe 14 Gas exhaust pipe 16 Boats 18 semiconductor wafer 20 coercive bulb 22 elevation mechanism 24 heating element 26 heat insulator 30 buffer plate 34, 40 groove 36, 42 seal Exhaust pipe

Continued on the front page (51) Int.Cl. ⁷ Identification code FI H01L 21/31 H01L 21/31 E (72) Inventor Noriyoshi Mita 1 No. 1, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa Pref. 72) Inventor Masaharu Abe 3210-1, Hongo, Kawajiri, Shiroyama-cho, Tsukui-gun, Kanagawa Prefecture Inside Tokyo Electron Sagami Co., Ltd. 56) References JP-A-2-156630 (JP, A) JP-A-2-1-1116 (JP, A) JP-A-62-154722 (JP, A) JP-A-64-46918 (JP, A) 54-102865 (JP, A) JP-A-1-170017 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/205 H01L 21/22-21/24 H01L 21 / 31 H01L 21/365 H01L 21/38-21/40 H01L 21/469 H01L 21/86

Claims (4)

(57) [Claims] 1. A heat treatment apparatus comprising: a reaction tube for heat-treating an object to be processed; and a gas introduction tube provided through the inside of the reaction tube from outside the reaction tube to feed a process gas into the reaction tube. A penetrating portion penetrating a lower side wall of the reaction tube; a reaction that is detachably attached to a tip portion of the penetration portion that protrudes into the reaction tube by a predetermined length, and extends to an upper position of the reaction tube in the attached state. a pipe stretch, is composed of a through portion of the gas introduction pipe formed of quartz, the reaction tube
A heat treatment apparatus characterized in that the inward extension is formed of SiC . 2. The heat treatment apparatus according to claim 1, further comprising: a buffer plate that is provided substantially horizontally at a position slightly below a ceiling of the reaction tube and has a plurality of openings. A heat treatment apparatus, wherein the uppermost end penetrates the buffer plate. 3. A thermal processing apparatus according to claim 1 or claim 2, further comprising a heating device arranged around the reaction tube, the reaction tube is a region surrounded by at least the heating device A heat treatment wherein the first component is made of SiC, and the second component is made of quartz; apparatus. 4. The heat treatment apparatus according to claim 3 , wherein a groove having an exhaust port is provided at a joint between the first component and the second component constituting the reaction tube. .