JP4786940B2 - Heat treatment apparatus and heat treatment method - Google Patents

Description

  The present invention relates to a heat treatment apparatus and a heat treatment method for heating a substrate with an infrared radiation source such as a lamp.

The heat treatment apparatus holds a container that accommodates the substrate, an infrared radiation source that heats the substrate that is provided outside the container and is accommodated in the container, and a peripheral portion of the substrate that is disposed within the container and accommodated in the container The substrate held by the susceptor is heated by being irradiated with infrared rays from an infrared radiation source.
During this heat treatment, the temperature of the peripheral edge of the substrate decreases due to heat conduction from the peripheral edge of the substrate to the susceptor, and it is difficult to maintain the in-plane thermal uniformity of the substrate.
Therefore, conventionally, in order to maintain the in-plane thermal uniformity of the substrate, a guard ring that supports the peripheral portion of the substrate is interposed between the susceptor and the substrate. In-plane soaking is improved.

However, in the above-described conventional technique, the temperature of the peripheral portion of the guard ring is lowered due to heat conduction from the peripheral portion of the guard ring to the susceptor, so that the uniform temperature of the guard ring cannot be maintained. If the guard ring does not maintain the thermal uniformity, it will be difficult to maintain the thermal uniformity of the substrate, even if a guard ring is installed at the corner or the outer periphery of the substrate, because the influence of the temperature gradient of the guard ring will also occur on the peripheral edge of the substrate. Met.
An object of the present invention is to provide a heat treatment apparatus and a heat treatment method capable of eliminating the above-described problems of the prior art and maintaining the temperature uniformity of a substrate by maintaining the temperature uniformity of a guard ring.

1st invention is the container which accommodates a board | substrate, the infrared radiation source which is provided outside a container and heats the board | substrate accommodated in a container, and is provided in a container and hold | maintains the board | substrate accommodated in a container A ring-shaped guard ring that is held on the susceptor and supports a peripheral portion of the substrate, and a guard ring that is held on the susceptor and is provided on an outer periphery of the guard ring. A heat treatment apparatus including a guard ring guard made of the same material and disposed in a ring shape in proximity to the guard ring.
Since the guard ring guard is disposed in a ring shape on the outer periphery of the guard ring in the vicinity of the guard ring, the infrared radiation source heats not only the substrate and the guard ring but also the guard ring guard. Therefore, the guard ring guard can prevent a temperature drop at the peripheral edge of the guard ring. As a result, the thermal uniformity of the guard ring, and thus the thermal uniformity of the substrate can be improved.

A second invention is the heat treatment apparatus according to the first invention, wherein the guard ring guard is composed of a plurality of divided segments.
If the guard ring guard is configured as a single piece, it is provided in a ring shape on the outer periphery of the guard ring, so the surface area increases and is more susceptible to thermal expansion than the guard ring. The guard ring guard can be reliably protected from damage due to thermal expansion.

According to a third invention, in the second invention, a guard ring receiver is provided between the susceptor and the guard ring guard, and the plurality of segments are loosely fitted in recesses provided in the guard ring receiver. It is the heat processing apparatus characterized by this.
Since the multiple segments that make up the guard ring guard are loosely fitted in the recesses of the guard ring receiver, even if the segments are thermally expanded, the ring-shaped arrangement of the segments can be maintained. It can be reliably protected.

A fourth invention is the heat treatment apparatus according to the third invention, wherein the guard ring and the guard ring guard are made of the same silicon as the substrate, and the guard ring receiver and the susceptor are made of quartz.
Since the guard ring and the guard ring guard are made of the same silicon as the substrate, it is possible to further improve the thermal uniformity of the guard ring and thus the thermal uniformity of the substrate.

According to a fifth aspect of the present invention, in the heat treatment space in the container containing the substrate, a ring-shaped guard ring is disposed in the vicinity of the substrate on the outer peripheral portion of the substrate, and the substrate and the guard ring are disposed on the substrate. When heat-treating the substrate by heating with an infrared radiation source outside the container, a guard ring guard is arranged in a ring shape in the vicinity of the guard ring on the outer periphery of the guard ring, and the heat treatment is performed. It is a heat treatment method characterized by performing.
Since the guard ring guard can prevent a temperature drop at the peripheral portion of the guard ring, it is possible to improve the thermal uniformity of the guard ring and thus the thermal uniformity of the substrate.

  According to the present invention, it is possible to improve the thermal uniformity of the guard ring and thus the thermal uniformity of the substrate.

Hereinafter, a heat treatment apparatus and a heat treatment method according to an embodiment of the present invention will be described.
The heat treatment apparatus heats a substrate in a hermetically sealed container that is cut off from the atmosphere under vacuum or normal pressure by a lamp unit outside the container, and rotates the substrate to heat the substrate uniformly. Yes. In general, a rotation mechanism that rotates a substrate has a rotation axis that rotates a substrate holding means (susceptor) that holds the substrate and a rotation transmission shaft that transmits the rotation to the rotation axis on a central axis of the substrate as a single axis configuration. Yes.

  However, if the rotation shaft and the rotation transmission shaft are configured as a single axis and overlapped on the central axis of the substrate, the temperature measurement point of the substrate heated by the lamp unit cannot be provided on the central axis of the substrate. If the temperature measurement point is not on the central axis of the substrate, the temperature at the central portion of the substrate cannot be directly measured. Therefore, it is difficult to effectively control the lamp unit, which is not preferable for heating the substrate uniformly.

  Therefore, in order to avoid this, as shown in FIG. 3, the rotating shaft of the susceptor 22 that holds the wafer W is formed by a cylindrical rotating body 15 having a hollow inside, and the rotation transmission shaft of the cylindrical rotating body 15 is formed. A temperature measuring point by the radiation thermometer 21 is also secured in the center portion of the bottom wall 11 by forming the rotating shaft 18 of the motor 17 arranged on the outer side, and the measured temperature at the center portion of the bottom wall 11 is secured. To be able to provide feedback.

  The heat treatment apparatus is a single-wafer rapid thermal process (RTP) apparatus that heats by a lamp unit 30 such as a halogen lamp, and a guard ring 25 is provided around the wafer W so that the thermal uniformity of the wafer W is achieved. To improve. Further, a guard ring guard and a guard ring guard receiver, which will be described later, are installed on the outer periphery of the guard ring 25.

As shown in FIG. 3, the heat treatment apparatus includes a heating container 10 and an infrared radiation source for heating a silicon wafer (hereinafter simply referred to as a wafer) W as a substrate in the heating container 10 through an upper wall 9 made of a quartz window. As a lamp unit 30. The bottom wall central portion 12 of the bottom wall 11 in the heating container 10 is made higher than the bottom wall peripheral portion 13 to form a storage space 14 that is one step lower than the bottom wall central portion 12 on the bottom wall peripheral portion 13. Yes. The cylindrical rotating body 15 is fitted to the bottom wall central portion 12 and is rotatably supported by a bearing 16 provided between the cylindrical rotating body 15 and the peripheral wall of the bottom wall central portion 12. A rotation shaft 18 of the motor 17 serving as a rotation transmission shaft passes through the bottom wall 11 of the heating container 10 and is inserted into the storage space 14 in the heating container 10. A gear 19 attached to the end of the rotating shaft 18 meshes with a gear 20 provided on the outer periphery of the cylindrical rotating body 15 to constitute a rotation transmission mechanism. As described above, since the rotation shaft and the rotation transmission shaft have a two-axis configuration, even if the wafer W is heated by the lamp unit 30 while rotating the cylindrical rotating body 15 by the rotation of the motor 17, the center of the bottom wall central portion 12 is maintained. A space is secured in the portion, and the radiation thermometer 21 can be installed at the center of the bottom wall central portion 12 together with the peripheral portion of the bottom wall 11.
Note that a portion above the storage space 14 in the heating container 10 constitutes a heat treatment space 23 in which the wafer W is stored.

The cylindrical rotating body 15 has a plate portion 15 a extending from the upper outer periphery to the upper peripheral portion of the bottom wall central portion 12. A plurality of plate portions 15a are provided on the outer periphery of the upper portion of the cylindrical rotating body 15 in order to support the wafer W in a substantially dot shape at substantially equal intervals. For example, three plate portions 15a are provided for three-point support, and four plate portions 15 are provided for four-point support.
Susceptors 22 for holding the wafer W are supported on the inner peripheral edge of the plate portion 15a. On the susceptor 22, a ring-shaped guard ring 25 that supports the peripheral edge of the wafer W is further provided to prevent a temperature drop at the peripheral edge of the wafer W. The guard ring 25 is made of silicon, which is the same material as the wafer W, for example.
In the present embodiment, a guard ring guard, which will be described later, is provided on the outer periphery of the guard ring 25. The guard ring guard is formed of the same material as the guard ring 25 and is arranged in a ring shape close to the guard ring 25. It has been. The guard ring guard will be specifically described with reference to FIGS. 1 and 2 showing details of the wafer holding unit.

FIG. 1 is a plan view of a wafer holding unit, and FIG. 2 is an enlarged cross-sectional view taken along line AA of FIG.
As shown in FIGS. 1 and 2, the wafer holding unit includes a guard ring 25, a guard ring guard 26, a guard ring guard receiver 27, and a susceptor 22.

  The guard ring 25 has a ring shape and supports the peripheral edge of the wafer W. The guard ring guard 26 is disposed in a ring shape on the outer periphery of the guard ring 25. The guard ring guard 26 includes a plurality of divided rectangular segments 261, and these are arranged in a ring shape on the outer periphery of the guard ring 25.

  The guard ring guard receiver 27 has a ring shape and holds the guard ring guard 26. As shown in FIG. 2, the guard ring guard receiver 27 has a ring-shaped recess 27a on the upper surface. A plurality of rectangular segments 261 are arranged in a ring shape in the ring-shaped recess 27a.

  The susceptor 22 has a rectangular shape, and a plurality of susceptors 22 are provided on the outer periphery of the wafer W at equal intervals. In the illustrated example, four are provided at intervals of 90 degrees. The susceptor 22 is provided in the radial direction of the wafer W so as to straddle the guard ring receiver 27 and under the periphery of the guard ring 25. The susceptor 22 has a concave portion 22a at the center of the upper surface, and a step portion 22b at the inner peripheral edge of the upper surface serving as a convex portion. Four portions of the ring-shaped guard ring receiver 27 are loosely fitted into the recesses 22 a of the four susceptors 22 to hold the guard ring receiver 27. Further, the guard ring 25 is held by engaging the four steps of the outer peripheral edge of the guard ring 25 with the stepped portions 22 b of the four susceptors 22.

  In particular, as shown in FIG. 1, a concave engagement portion 25 a is provided on the lower surface of the outer peripheral edge of the guard ring 25, and the protrusion 25 b engages the engagement portion 25 a of the guard ring 25 with the step portion 22 b of the susceptor 22. The guard ring 25 is positioned on the susceptor 22 by providing a locking portion 22 c having a shape and locking the locked portion 25 a of the guard ring 25 to the locking portion 22 c of the susceptor 22.

As shown in FIG. 2, the guard ring guard 26 is brought close to the guard ring 25 by leaving a part 22 d of the convex portion at the inner peripheral edge portion of the susceptor 22. Further, the step 22b of the susceptor 22 has a size such that the upper surface of the guard ring guard 26 accommodated in the recess 22a of the susceptor 22 via the guard ring receiver 27 and the upper surface of the guard ring 25 are substantially flush with each other. A step is provided. When the upper surface of the guard ring guard 26 and the upper surface of the guard ring 25 are substantially flush, the guard ring guard 26 is heated evenly with the guard ring 25.
The susceptor 22 that holds the guard ring guard receiver 27 and the guard ring 25 is provided so as to be fixed to the plate portion 15a of the cylindrical rotating body 15 described above.

The guard ring 25 and the guard ring guard 26 described above are made of, for example, the same silicon as the wafer W, and the guard ring receiver 27 and the susceptor 22 are made of, for example, quartz.
The wafer holding unit is configured as described above.

  Next, a method for heat-treating the wafer W using the heat treatment apparatus described above will be described.

A wafer W carried into the heating container 10 by a substrate transfer mechanism (not shown) is held on a guard ring 25 provided on the upper portion of the cylindrical rotating body 15 via a susceptor 22. The inside of the heating container 10 is made an inert gas atmosphere by exhausting from the exhaust port (not shown) while supplying an inert gas such as N ₂ gas from the gas supply port (not shown) into the heating container 10. . Further, the cooling water (not shown) is made to flow through a cooling passage (not shown) provided on substantially the entire surface of the bottom wall central portion 12 located below the wafer W, the guard ring 25, and the plate portion 15a. Cool the whole thing.

  When the motor 17 is driven to rotate the rotating shaft 18, the cylindrical rotating body 15 rotates through the gears 19 and 20, and the wafer W held on the susceptor 22 rotates through the guard ring 25.

  When the rotation is stabilized, the lamp unit 30 is turned on to turn on the plurality of ring-shaped lamps 31 at the same time, and from the lamp 31 through the upper wall 9 of the heating container 10, the wafer W, the guard ring 25, and the guard ring. Infrared radiation is irradiated toward the guard 26 to heat the rotating wafer W at high speed. The temperature of the wafer W is measured by a plurality of radiation thermometers 21 provided from the center of the bottom wall central portion 12 to the peripheral portion, and is feedback-controlled by the lamp unit 30. In addition, since the bottom wall central portion 12 is uniformly cooled in a well-balanced manner by the cooling water flowing through the cooling passages provided on substantially the entire surface of the bottom wall central portion 12, the wafer W is uniformly heated. Thereby, the wafer W is heat-treated.

  After the heat treatment, the lamp 31 is turned off, the operation of the motor 17 is stopped, and the rotation of the cylindrical rotating body 15 is stopped. The wafer W after the heat treatment is unloaded from the heating container 10 by a substrate transfer mechanism (not shown).

  By the way, when the wafer W is heated by the lamp, the guard ring guard 26 is arranged in a ring shape on the outer periphery of the guard ring 25 so as to be close to the guard ring 25, so that not only the wafer W and the guard ring 25 are provided. The guard ring guard 26 is also heated. This heating generates heat radiation from the guard ring guard 26 toward the guard ring 25. Thereby, the temperature fall by the heat conduction from the peripheral part of the guard ring 25 to the susceptor 22 is suppressed, and the thermal fluctuation of the guard ring can be suppressed. Therefore, the guard ring guard 26 can prevent a temperature drop at the peripheral edge of the guard ring 25, and the thermal uniformity of the guard ring 25 and thus the thermal uniformity of the wafer W can be improved.

  Further, the guard ring guard 26 is composed of a plurality of divided segments 261, and these are arranged in a ring shape on the outer periphery of the guard ring 25, so that the guard ring guard 26 is reliably protected from damage due to thermal expansion. it can. That is, when the guard ring guard 26 is configured as a single body, the guard ring guard 26 is provided in a ring shape on the outer periphery of the guard ring 25, so that the surface area is larger than the guard ring 25 and is more susceptible to thermal expansion. However, since it is comprised from the several segment 261 so that it is hard to receive to the influence of thermal expansion, the guard ring guard 26 can be reliably protected from the damage by thermal expansion.

  Further, since the guard ring receiver 27 is provided between the guard ring guard 26 and the susceptor 22 and the guard ring guard 26 is loosely fitted in the recess 27a of the guard ring receiver 27 so as to be arranged in a ring shape, the segment 261 is formed. Even if it is thermally expanded, the guard ring guard 26 can be more reliably protected from damage due to thermal expansion without disturbing the ring-shaped arrangement of the segments 261.

  Further, in order to make the heating condition of the guard ring 25 the same as that of the wafer W and the guard ring guard 26, the guard ring 25 is made of silicon made of the same material as the wafer W and the guard ring guard 26, and holds the guard ring receiver 27 and the susceptor. Since 22 is made of quartz, the thermal uniformity of the guard ring 25 and thus the thermal uniformity of the wafer W can be further improved.

  As described above, according to the embodiment, the temperature decrease in the peripheral portion of the guard ring due to heat transfer can be covered by the guard ring guard. Therefore, in the wafer heat treatment process, which is one process of the semiconductor manufacturing process. Therefore, it is possible to stably ensure the thermal uniformity of the wafer and heat-treat the wafer under accurate temperature control. Moreover, the thermal fluctuation of the guard ring can be suppressed and the life of the guard ring can be extended.

  The heat treatment apparatus is not limited to the single wafer high speed heat treatment apparatus in the embodiment in which the rotation transmission mechanism is present in the container. For example, in an apparatus in which an internal rotor for rotating a susceptor is provided in a heating container, and this internal rotor is magnetically coupled to an external rotor provided outside the container via a vacuum wall so that the rotation transmission mechanism is removed from the inside of the container. Is also applicable.

It is a top view of the wafer holding part which comprises a part of heat processing apparatus in embodiment. It is an AA cross-sectional enlarged view of FIG. It is a schematic sectional drawing of the single-wafer | sheet-fed high-speed heat processing apparatus in embodiment.

Explanation of symbols

W substrate 10 heating vessel 22 susceptor 25 guard ring 26 guard ring guard 27 guard ring receiver 30 lamp unit (infrared radiation source)
261 segments

Claims (5)

A container for containing a substrate;
Provided outside the container, and the infrared radiation source to heat the substrate accommodated in the container,
Provided in the vessel, a susceptor for holding the substrate accommodated in the container,
A ring-shaped guard ring that is directly held on the stepped portion provided on the inner peripheral edge of the susceptor and supports the peripheral edge of the substrate from below ;
The susceptor is held in a recess provided on the outer periphery from the stepped portion , and is disposed in a ring shape on the outer periphery of the guard ring, in proximity to the guard ring , and the upper surface of the guard ring. A guard ring guard arranged to be substantially flush with the upper surface and made of the same material as the guard ring ;
The heat processing apparatus provided with.   The heat treatment apparatus according to claim 1, wherein the guard ring guard includes a plurality of divided segments. A guard ring receiver is provided between the concave portion provided in the susceptor and the guard ring guard,
The heat treatment apparatus according to claim 2, wherein the guard ring guard is loosely fitted on a recess provided in the guard ring receiver. The guard ring and to configure the guard ring guard in the same silicon as the substrate,
The heat treatment apparatus according to claim 3, characterized in that said guard ring receiver and the susceptor was made of quartz. In the heat treatment space in the container containing the substrate,
A ring-shaped guard ring is disposed in the vicinity of the substrate on the outer periphery of the substrate,
Per the annealing the substrate by performing infrared radiation from the outside of the container of the infrared radiation source to the substrate and the guard ring,
A guard ring guard made of the same material as the guard ring is arranged in a ring shape on the outer periphery of the guard ring, and the upper surface is substantially the same as the upper surface of the guard ring guard. A heat treatment method, wherein the heat treatment is performed so as to be flush with each other.

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