JP6511309B2 - Substrate heating apparatus and substrate heating method - Google Patents

Description

  The present invention relates to a substrate heating apparatus and a substrate heating method using microwaves.

  BACKGROUND Conventionally, a substrate heating apparatus using a lamp heater to heat a semiconductor wafer (hereinafter simply referred to as “wafer”) is known (see, for example, Patent Document 1). In this substrate heating apparatus, a plurality of lamp heaters are disposed to irradiate infrared rays to the back surface of the wafer, while the central portion of the back surface of the wafer is used to prevent the infrared rays from being concentrated on the central portion of the wafer. Install an infrared shielding plate so as to face the

JP, 2008-288451, A

  However, since the lamp heater is expensive, the substrate heating apparatus of Patent Document 1 requiring a plurality of lamp heaters is costly. In particular, when the lamp heater is exposed to a space where plasma is generated, abnormal discharge may occur from the lamp heater, so the substrate heating apparatus of Patent Document 1 can be integrated with an apparatus for applying plasma processing to a wafer. In addition, as a result, the cost of the substrate processing system is increased.

  An object of the present invention is to provide a substrate heating apparatus and a substrate processing method capable of suppressing an increase in cost.

In order to achieve the above object, a substrate heating apparatus according to the present invention comprises a processing chamber for containing a substrate and an antenna for emitting microwaves to the inside of the processing chamber. The moving mechanism is provided to move the substrate, and the wall of the processing chamber includes a non-linear portion in the cross section of the processing chamber, and the moving mechanism moves the substrate along the central axis of the processing chamber , the processing chamber exhibits a saphenous hemisphere dome shape, the antenna is characterized Rukoto disposed on top of the processing chamber.

According to the present invention, seen including a wall portion of the processing chamber in the cross section of the treatment chamber microwaves into the interior is radiated non-linear portion, it presents a hemispherical dome-shaped processing chamber is subjected, antenna processing chamber Since the direction of the electric field generated by each microwave reflected from the wall is not uniform because it is disposed at the top of the chamber, a plurality of standing waves are generated in various places inside the process chamber, When the substrate moves along the central axis of the processing chamber, the entire surface of the substrate can be uniformly exposed to the standing waves. That is, the substrate can be uniformly heated using an antenna that radiates microwaves, thereby eliminating the need to use a lamp heater for heating the substrate. As a result, an increase in cost can be suppressed.

FIG. 1 is a cross-sectional view schematically showing a configuration of a substrate heating apparatus according to an embodiment of the present invention. It is a figure for demonstrating the model of the processing chamber of the hemispherical dome shape used for simulation. It is a figure which shows the result of simulation of distribution of the electric field in the model of a processing chamber of hemispherical dome shape. FIG. 4 (A) shows the position of the standing wave at the height h ₁ of FIG. 2; FIG. 4 (B) shows the height of FIG. 2 is shown the position of the standing wave in h _2, FIG. 4 (C) shows the position of a standing wave in the height h ₃ of FIG. It is a figure for demonstrating the model of the conical processing chamber used for simulation. It is a figure which shows the result of simulation of distribution of the electric field in the model of a conical processing chamber. Is a diagram showing the position of a standing wave in the simulation results of FIG. 6, FIG. 7 (A) shows the position of the standing wave at the height h ₁ of FIG. 5, FIG. 7 (B) of FIG. 5 High is shown the position of the standing wave in h _2, FIG. 7 (C) shows the position of a standing wave in the height h ₃ of FIG. It is process drawing which shows the substrate heating method which concerns on this Embodiment. It is a graph which shows the temperature dependence of reflected power of silicon, and absorption power. FIG. 10A is a cross-sectional view schematically showing a configuration of a modified example of the substrate heating apparatus of FIG. 1, FIG. 10A shows a first modified example, and FIG. 10B shows a second modified example. It is process drawing which shows the modification of the substrate heating method which concerns on this Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing the configuration of a substrate heating apparatus according to the present embodiment.

  In FIG. 1, the substrate heating apparatus 10 radiates microwaves toward the inside of the processing chamber 11, the processing chamber 11 for storing the wafer W, the stage 12 (mounting table) disposed inside the processing chamber 11, and And an exhaust mechanism 14 for exhausting the inside of the processing chamber 11.

  The processing chamber 11 has a substantially cylindrical main body portion 15 and a hemispherical dome portion 16 which covers the upper side of the main body portion 15. The central axis of the main body portion 15 and the central axis of the dome portion 16 substantially coincide, and the wall portion of the dome portion 16 is a curved portion in the cross section of the dome portion 16 cut at a plane including the central axis. A loading / unloading port 17 for loading / unloading the wafer W is disposed on the side surface of the main body 15, and the loading / unloading port 17 is covered by a gate valve mechanism 18. In addition, the inner wall surface of the processing chamber 11, in particular, the inner wall surface of the dome portion 16, is treated so that the microwaves are easily reflected.

  The gate valve mechanism 18 has a base 19 disposed so as to surround the loading / unloading port 17 on the outer surface of the main body 15, and a valve body (valve) 20 which is detachable from the base 19 and blocks the loading / unloading port 17. The O-ring 21 seals between the base 19 and the valve 20. Further, the valve 20 has a valve choke groove 22 which is opened to face a gap formed with the base 19. The depth of the valve choke groove 22 is, for example, 1⁄4 of the wavelength of the microwave emitted from the microwave antenna 13. Both the O-ring 21 and the valve choke groove 22 are arranged to surround the outlet 17 when the valve 20 is attached to the base 19.

  The stage 12 has a substantially cylindrical shape, and the wafer W is mounted on the upper surface 12 a. The central axis of the stage 12 also substantially coincides with the central axes of the main body portion 15 and the dome portion 16. A plurality of lift pins 23 project upward from the upper surface 12 a, and each lift pin 23 supports the wafer W. In the present embodiment, each lift pin 23 is configured to be freely protruded from the upper surface 12 a. An annular stage choke groove 24 is formed on the side surface of the stage 12 so as to be orthogonal to the central axis. The depth of the stage choke groove 24 is, for example, 1⁄4 of the wavelength of the microwave emitted from the microwave antenna 13. The stage 12 has a rod 25 extending downward along the central axis, and the rod 25 is connected to a stage raising and lowering mechanism (not shown). The stage raising and lowering mechanism moves the stage 12 along the central axis, that is, in the inside of the processing chamber 11 in the vertical direction in the drawing. Each lift pin 23 protrudes along the central axis to move the wafer W in the vertical direction in the drawing.

  The microwave antenna 13 is disposed on the top of the dome portion 16 and is connected via a waveguide 26 to a microwave source 27 which incorporates a magnetron (not shown) and the like. The microwave antenna 13 radiates the microwaves propagated from the microwave source 27 through the waveguide 26 into the interior of the dome portion 16.

  The exhaust mechanism 14 has an exhaust pipe 28 communicating with the inside of the processing chamber 11, and an exhaust pump 29 connected to the exhaust pipe 28, and exhausts the inside of the processing chamber 11 to make the pressure inside the processing chamber 11 desired. Maintain pressure.

  The gate valve mechanism 18 has a valve microwave absorber 30 disposed in the gap between the base 19 and the valve 20. The valve microwave absorber 30 is disposed so as to surround the inlet / outlet 17 outside the valve choke groove 22 when viewed from the inlet / outlet 17. Furthermore, inside the processing chamber 11, an internal microwave absorber 31 is disposed on the opposite side of the microwave antenna 13 via the stage 12 on which the wafer W is mounted, that is, at the bottom of the processing chamber 11. The valve microwave absorber 30 and the internal microwave absorber 31 are made of a dielectric, and in particular, aluminum nitride, which is a material having a large dielectric loss tangent (Tandel) value, and the purity is somewhat low (for example, the purity is about 99.5%) ) Alumina is preferably used.

  In the substrate heating apparatus 10, when the wafer W is heated by causing the wafer W to consume the microwaves radiated from the microwave antenna 13 as described later, no plasma is generated. It is conceivable that part of the wave propagates on the side of the stage 12 and leaks from the inside of the processing chamber 11 to the outside through the inlet / outlet 17. First, the stage choke groove 24 propagates on the side of the stage 12. Attenuates the wave. Furthermore, among the microwaves that have passed over the stage choke groove 24, the microwaves leaking to the lower part of the main body portion 15 are consumed by the internal microwave absorber 31 and disappear, and the microwaves of the base 19 and the valve 20 The microwaves leaking into the gap are first attenuated by the valve choke groove 22 and then consumed by the valve microwave absorber 30. Accordingly, the substrate heating apparatus 10 can prevent the microwaves from leaking to the outside of the processing chamber 11. In particular, since there is a space in the lower part of the main body 15, a relatively large internal microwave absorber 31 can be disposed, thereby reliably consuming microwaves and preventing leakage to the outside. be able to.

  The substrate heating apparatus 10 further includes an apparatus controller 32, which controls the operation of each component according to a predetermined program.

  By the way, when the present inventor processed the wafer in the microwave plasma apparatus prior to the present invention, when the microwave was irradiated without generating plasma, the wafer absorbed most of the microwave and the wafer was heated. I confirmed that.

  Therefore, in order to uniformly heat the wafer by microwaves, the shapes of various processing chambers were examined. Specifically, when examining the shape of the processing chamber, a model 33 (see FIG. 2) of a hemispherical dome-shaped processing chamber which is lowered and a model 34 (see FIG. 5) of a conical processing chamber which is lowered. To simulate the distribution of microwaves when microwaves are emitted from the microwave antenna 13 at the top in each of the models 33 and 34, in particular, the distribution of the electric field (current density) generated by each microwave. The For the simulation, COMSOL Multiphysics (registered trademark) of COMSOL AB was used.

  FIG. 3 is a view showing the result of simulation of the distribution of the electric field in the model of the hemispherical dome-shaped processing chamber.

As shown in FIG. 3, in the hemispherical dome-shaped processing chamber model, the direction of the electric field (indicated by an arrow in the drawing) generated by each microwave reflected from the wall of the processing chamber was disturbed. Moreover, when the position of the standing wave generated by the interference of each microwave was confirmed in the said model, as shown in FIG. 4, it is confirmed that the position of the standing wave is changing according to the height of the processing chamber. It was done. 4 (A) shows the distribution of standing waves in the horizontal plane of height h ₁ in the model of FIG. 2, and FIG. 4 (B) shows the standing in the horizontal plane of height h ₂ in the model of FIG. The distribution of waves is shown, and FIG. 4 (C) shows the distribution of standing waves in the horizontal plane of height h ₃ in the model of FIG. In each figure, darker portions indicate standing waves, and shades of color indicate magnitudes of intensity of the standing waves. The dark part outside each figure is a part where no electric field exists. Since the shape of the processing chamber is symmetrical with respect to the central axis, the standing waves are also symmetrical with respect to the central axis, that is, circularly distributed in the horizontal plane.

  FIG. 6 is a diagram showing the results of simulation of the distribution of the electric field in the conical processing chamber model.

As shown in FIG. 6, in the conical processing chamber model, the directions of the electric fields (indicated by arrows in the figure) generated by the respective microwaves reflected from the wall of the processing chamber were aligned. Moreover, when the position of the standing wave generated by the interference of each microwave was confirmed in the said model, as shown in FIG. 7, even if the height of the processing chamber changes, the position of the standing wave hardly changes That was confirmed. 7 (A) shows the distribution of standing waves in the horizontal plane of height h ₁ in the model of FIG. 5, and FIG. 7 (B) shows the standing in the horizontal plane of height h ₂ in the model of FIG. FIG. 7C shows the distribution of waves, and FIG. 7C shows the distribution of standing waves in the horizontal plane of height h ₃ in the model of FIG. 5. The lightness and darkness of the color of each figure are synonymous with the lightness and darkness of the color of FIG. 4 (A)-FIG.4 (C).

  The inventor has found that the position of the standing wave changes according to the height of the processing chamber in the hemispherical dome-shaped processing chamber, while the position of the standing wave changes according to the height of the processing chamber in the conical processing chamber. The following mechanism was inferred as the reason why the position does not change. That is, in the hemispherical dome-shaped processing chamber, the wall portion of the processing chamber is a curved portion and does not have a straight portion, so that the direction of each microwave reflected from the wall portion of the processing chamber is not uniform. The direction of the electric field generated by each microwave is disturbed, and as a result, interference of each microwave is generated in each place of the processing chamber, while in the conical processing chamber, the wall of the processing chamber is a straight portion, The direction of each microwave reflected from the wall was uniform, and the direction of the electric field generated by each microwave was aligned, and as a result, it was guessed that the interference of each microwave occurred only at a specific place in the processing chamber.

  In addition, the inventor takes into consideration that the portion of the wafer exposed to the standing wave is heated, and from the result of the above simulation, in the conical processing chamber, each standing wave according to the height of the processing chamber Because the position of the wafer does not change, even if the wafer is moved up and down in the processing chamber, only a specific part of the wafer is exposed to the standing wave, and the wafer can not be heated uniformly. Since the position of each standing wave changes in the processing chamber according to the height of the processing chamber, moving the wafer up and down in the processing chamber makes it possible to uniformly expose the entire surface of the wafer to each standing wave, as a result. We have found that the wafer can be heated uniformly. The present invention is based on this finding.

  FIG. 8 is a process diagram showing a substrate heating method according to the present embodiment.

  In FIG. 8, first, the stage 12 is lowered to a position where the wafer W loaded from the loading / unloading port 17 can be placed on the upper surface 12a, and the loaded wafer W is supported approximately horizontally by each lift pin 23 (FIG. A)).

  Next, the stage 12 is moved upward such that the stage choke groove 24 is closer to the microwave antenna 13 than the inlet / outlet 17, that is, the stage choke groove 24 is positioned above the inlet / outlet 17 (FIG. B)).

  Then, the microwaves are radiated from the microwave antenna 13 into the interior of the processing chamber 11, and each lift pin 23 is protruded from the upper surface 12a to keep the wafer W substantially horizontal, up and down along the central axis of the dome portion 16. (FIG. 8 (C), FIG. 8 (D)). At this time, since the position of each standing wave caused by the interference of the microwave reflected from the wall of the dome portion 16 changes according to the height, each portion of the wafer W moves up and down inside the dome portion 16 At the time, each standing wave is exposed, and as a result, the entire surface of the wafer is uniformly exposed to each standing wave, and the wafer W is uniformly heated.

  Then, after the temperature of the wafer W reaches a desired temperature, the method ends.

  According to the substrate heating method according to the present embodiment, the wall portion of the dome portion 16 is a curved portion in the cross section of the dome portion 16 of the processing chamber 11 where microwaves are radiated from the microwave antenna 13 to the inside. The direction of the electric field generated by each of the microwaves reflected from the part is disturbed, and a plurality of standing waves are generated at each place inside the dome part 16. Therefore, when the wafer W moves inside the dome part 16, the Each portion is exposed to each of the plurality of standing waves, and as a result, the entire surface of the wafer W can be uniformly exposed to each standing wave to heat the entire wafer W. Further, since the microwave antenna 13 is used to heat the entire wafer W, it is possible to eliminate the need to use a lamp heater to heat the wafer W. As a result, it is possible to suppress an increase in cost.

  Further, in the substrate heating method according to the present embodiment, since the shape of the dome portion 16 is symmetrical with respect to the central axis, each standing wave is also symmetrical with respect to the central axis, that is, annularly distributed in the horizontal plane. The diameter of each standing wave changes along the central axis because the position of each standing wave changes accordingly. Therefore, by moving the wafer W up and down while maintaining the wafer W substantially along the central axis of the dome portion 16, each portion of the wafer W can surely be exposed to a standing wave, thereby ensuring that the wafer W is uniform. It can be heated to

  Furthermore, in the substrate heating method according to the present embodiment, when the microwave antenna 13 radiates microwaves, the stage 12 brings the stage choke groove 24 closer to the microwave antenna 13 than the loading / unloading port 17, so microwaves are carried out. Before reaching the inlet 17, it can be extinguished by the stage choke groove 24 to prevent the microwaves from leaking from the inlet 17.

  Further, as shown in FIG. 9, the power reflected by silicon constituting the wafer W (hereinafter referred to as "reflected power") is rapidly increased at a predetermined temperature, for example, at a temperature exceeding 300.degree. The power absorbed by silicon (hereinafter referred to as "absorbed power") rapidly decreases around the point where the temperature exceeds a predetermined temperature. That is, silicon does not rapidly absorb microwaves above a predetermined temperature. From this, if the desired temperature is around 300 ° C., the low temperature region (eg, the temperature is 300 ° C.) as compared to the amount of microwave absorption in the high temperature region (eg, the temperature exceeds 300 ° C.) in the surface of the wafer W The region where the microwave absorption is not increased. That is, since the low temperature region is heated more positively than the high temperature region, more uniform heating of the wafer W can be expected.

  Furthermore, in the substrate heating method according to the present embodiment, the moving distance of the wafer W inside the dome portion 16 so that the amount of heat received from each standing wave (the amount of absorption of the microwaves) becomes equivalent for each portion of the wafer W. And travel time is adjusted.

  Further, as shown in FIGS. 4A to 4C, since a standing wave does not occur in the vicinity of the central axis at any height, a portion intersecting the central axis of the wafer W, for example, a wafer The center of W may not be heated. In the present embodiment, correspondingly, a heater (not shown) may be embedded near the central axis of upper surface 12a of stage 12 to heat the central portion of wafer W by the heater, or stage 12 The vicinity of the central axis of the upper surface 12a of the upper surface 12a is constituted by a heat transfer member with good heat conductivity, and heat is transferred from the portion other than the central portion of the wafer W exposed to each standing wave and heated via the heat transfer member It may be transmitted to the center of W.

  As mentioned above, although this invention was demonstrated using the said embodiment, this invention is not limited to the said embodiment.

  In the substrate heating apparatus 10 described above, the upper portion of the processing chamber 11 is configured by the hemispherical dome portion 16, but the shape of the upper portion of the processing chamber 11 is not limited to the hemispherical shape. If the direction of each of the microwaves reflected from the wall of the processing chamber 11 is not uniform and the direction of the electric field generated by each microwave is disturbed, as a result, interference of each microwave is generated in each part of the processing chamber 11 and processed Since the position of the standing wave changes according to the height of the chamber 11, the wall of the processing chamber 11 may include a non-linear portion in the upper section of the processing chamber 11, for example, the central axis of the processing chamber 11 The cross-sectional shape cut in a plane including the shape may exhibit a semi-elliptical shape (FIG. 10 (A)), and in the same cross section, the wall may be composed of a plurality of straight portions having different inclination angles (FIG. 10) (B)).

  Further, in the substrate heating method according to the present embodiment described above, the moving distance and moving time of the wafer W inside the dome portion 16 are adjusted so that the amount of heat received from each standing wave becomes equal for each portion of the wafer W. However, when it is desired to heat only a specific part of the wafer W, it is preferable to adjust the moving distance and moving time of the wafer W so that the specific part is exposed to the standing wave for a long time.

  Furthermore, in the substrate heating method according to the present embodiment described above, each lift pin 23 moves the wafer W up and down, but without changing the amount of protrusion of each lift pin 23 from the upper surface 12a, FIG. The wafer W may be moved up and down by moving the stage 12 up and down as shown in FIG. 11D. In this case, when moving the stage 12 up and down to move the wafer W up and down, it is preferable that the stage choke groove 24 be always positioned above the loading / unloading port 17 (FIG. 11B to FIG. 11 (D)). Thereby, it is possible to prevent the microwaves not attenuated by the stage choke groove 24 from leaking from the loading / unloading port 17. Further, in this case, it is possible to eliminate the need for arranging the vertical mechanism for causing the lift pins 23 to project from the upper surface 12a, thereby simplifying the configuration of the substrate heating apparatus 10 and further reducing the cost.

  Further, an object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiment to the device controller 32, and the CPU of the device controller 32 stores the program code stored in the storage medium. Is also achieved by reading out and executing.

  In this case, the program code itself read out from the storage medium implements the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Further, as a storage medium for supplying the program code, for example, RAM, NV-RAM, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD (DVD (DVD) Any optical disk such as ROM, DVD-RAM, DVD-RW, DVD + RW), magnetic tape, non-volatile memory card, other ROM, etc., as long as the program code can be stored. Alternatively, the program code may be supplied to the device controller 32 by downloading from another computer, database, or the like (not shown) connected to the Internet, a commercial network, a local area network or the like.

  Further, by executing the program code read by the device controller 32, not only the functions of the above-described embodiment are realized, but also an operating system (OS) operating on the CPU based on an instruction of the program code. And the like perform part or all of the actual processing, and the functions of the above-described embodiment are realized by the processing.

  Furthermore, after the program code read out from the storage medium is written in the memory provided in the function expansion board inserted into the device controller 32 or the function expansion unit connected to the device controller 32, based on the instruction of the program code Also included is a case where a CPU or the like provided in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing of the above-described embodiment is realized by the processing.

  The form of the program code may be an object code, a program code executed by an interpreter, script data supplied to an OS, or the like.

DESCRIPTION OF SYMBOLS 10 substrate heating apparatus 11 process chamber 13 microwave antenna 16 dome part 17 inlet-outlet 18 gate valve mechanism 22 valve choke groove 24 stage choke groove 30 valve microwave absorber 31 internal microwave absorber

Claims (9)

A substrate heating apparatus comprising: a processing chamber for containing a substrate; and an antenna for emitting microwaves to the inside of the processing chamber,
A moving mechanism for moving the substrate inside the processing chamber;
In the cross section of the processing chamber, the wall of the processing chamber includes a non-linear portion,
The movement mechanism moves the substrate along a central axis of the processing chamber ,
The processing chamber exhibits a hemispherical dome shape that is Fushimi, wherein the antenna substrate heating apparatus according to claim Rukoto disposed on top of the processing chamber. A substrate heating apparatus comprising: a processing chamber for containing a substrate; and an antenna for emitting microwaves to the inside of the processing chamber,
A moving mechanism for moving the substrate inside the processing chamber;
In the cross section of the processing chamber, the wall of the processing chamber includes a non-linear portion,
The movement mechanism moves the substrate along a central axis of the processing chamber,
The processing chamber is the cross-sectional shape which is taken along a plane including the central axis of the processing chamber exhibits a semi-elliptical shape, wherein the antenna board heater you being disposed on top of the processing chamber. A substrate heating apparatus comprising: a processing chamber for containing a substrate; and an antenna for emitting microwaves to the inside of the processing chamber,
A moving mechanism for moving the substrate inside the processing chamber;
The movement mechanism moves the substrate along a central axis of the processing chamber,
The processing chamber wall is board heater you characterized in that inclined angle to each other are composed of different plural linear portions in the cross section of the processing chamber. 3. The substrate heating apparatus according to claim 1, wherein a wall portion of the processing chamber is a curved portion in a cross section of the processing chamber. It further comprises a columnar mounting table disposed inside the processing chamber and mounting the substrate,
The substrate heating apparatus according to any one of claims 1 to 4, wherein a groove is formed on the side surface of the mounting table. And a gate valve formed on a side wall of the processing chamber,
The substrate heating apparatus according to claim 5, wherein when the antenna radiates microwaves, the mounting table moves toward the antenna to bring the groove closer to the antenna than the gate valve. 7. The substrate heating apparatus according to claim 5, wherein the mounting table moves with the substrate placed thereon to function as the moving mechanism. The substrate heating apparatus according to any one of claims 1 to 7 , further comprising a dielectric disposed on the opposite side of the substrate with respect to the substrate inside the processing chamber. 9. The substrate heating apparatus according to claim 8, wherein the dielectric is made of aluminum nitride or alumina.