JP2014130900A - Heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater capable of uniformly heating a substrate mounted on a boat type sample holder and suppressing heating time.SOLUTION: The heater that heats a substrate mounted on a mounting surface of a sample holder having a configuration in which a plurality of substrate plates each having a mounting surface are parallely arranged in a normal direction of the mounting surface includes: a chamber in which the sample holder is stored; and a heater disposed between the periphery of the sample holder and the substrate plates in the chamber.

Description

  The present invention relates to a heating apparatus used in a semiconductor manufacturing process for performing heat treatment of a substrate.

  In a manufacturing process of a semiconductor device such as a solar cell, the substrate is heated in preheating before the processing process or annealing in the processing process. In addition, since the number of substrates processed per hour is an important performance, a batch-type heat treatment method that simultaneously processes a plurality of substrates is employed.

  In the batch type, a sample holder on which a plurality of substrates are mounted is used. Examples of the sample holder include a cart type in which substrates are arranged horizontally on a horizontal plate, and a boat type in which a plurality of substrates are arranged vertically.

  In the cart type sample holder, the substrate is heated by a heater disposed above or in the vertical direction of the sample holder so as to face the mounting surface of the sample holder on which the substrate is disposed. However, when a cart-type sample holder is used, there is a problem that the installation area (footprint) of the heating device is large. On the other hand, if a boat type sample holder is used, the installation area of an apparatus can be suppressed (for example, refer patent document 1).

JP 2002-75884 A

  However, in the configuration in which the heater is arranged around the sample holder in order to heat the substrate mounted on the boat type sample holder, since the distance from the heater is not uniform, the heating uniformity is reduced and the heating time is also increased. There was a problem of becoming.

  In view of the above problems, it is an object of the present invention to provide a heating apparatus that can uniformly heat a substrate mounted on a boat-type sample holder and suppress the heating time.

  According to one aspect of the present invention, there is provided a heating apparatus that heats a substrate mounted on a mounting surface of a sample holder having a configuration in which a plurality of substrate plates each having a mounting surface are arranged in parallel in the surface normal direction of the mounting surface. Thus, a heating device is provided that includes a chamber in which the sample holder is stored, and a heater disposed in the chamber around the sample holder and between the substrate plates.

  ADVANTAGE OF THE INVENTION According to this invention, the heating apparatus which can heat the board | substrate mounted in the boat type sample holder uniformly, and can suppress a heating time can be provided.

It is a schematic diagram which shows the structure of the heating apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the sample holder stored in the heating apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the example of arrangement | positioning of the heater of the heating apparatus which concerns on the 1st Embodiment of this invention. It is a graph for demonstrating the characteristic of the heater of the heating apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the heating apparatus of a comparative example. It is a graph which shows the change of the substrate temperature by the heat processing of the heating apparatus which concerns on the 1st Embodiment of this invention, and the heating apparatus of a comparative example. It is a schematic diagram which shows the structure of the heating apparatus which concerns on the 2nd Embodiment of this invention. It is a schematic diagram which shows the other structure of the heating apparatus which concerns on the 2nd Embodiment of this invention. It is a graph which shows the temperature change of the sample holder by the heat processing of the heating apparatus which concerns on the 2nd Embodiment of this invention, and a board | substrate. It is a schematic diagram which shows the example which used the semiconductor manufacturing apparatus concerning the 2nd Embodiment of this invention for a part of in-line type film-forming apparatus. It is a table | surface which shows the carrier lifetime of the thin film formed in the board | substrate heat-processed by the heating apparatus which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic. Further, the embodiment described below exemplifies an apparatus and a method for embodying the technical idea of the present invention, and the embodiment of the present invention has the following structure and arrangement of components. It is not something specific. The embodiment of the present invention can be variously modified within the scope of the claims.

(First embodiment)
The heating apparatus 1 according to the first embodiment of the present invention is a heating apparatus that heats a plurality of substrates 100 mounted on a boat-type sample holder 10 having a plurality of substrate plates 11 as shown in FIG. A chamber 20 in which the sample holder 10 is stored, and a heater 30 disposed around the sample holder 10 and between the substrate plates 11 in the chamber 20.

  As shown in FIG. 2, the sample holder 10 is a boat type in which a plurality of substrate plates 11 each having a mounting surface 110 are arranged in parallel to the surface normal direction of the mounting surface 110. Each bottom portion of the substrate plate 11 is fixed by a bottom plate 12. By using the boat type sample holder 10 having a plurality of mounting surfaces 110, the installation area of the heating device 1 can be reduced. In addition, the number of substrates 100 that can be processed in one film formation process can be increased, and the overall processing time can be shortened. Note that the number of substrates mounted on one mounting surface 110 can be arbitrarily set.

  FIG. 3 shows a form example of the heater 30 arranged on the mounting surface 110 in the heating apparatus 1 when viewed from the surface normal direction of the mounting surface 110. In the example shown in FIG. 3, a tubular heater that extends on the mounting surface 110 in parallel with the main surface of the bottom plate 12 is provided. For example, a lamp heater or the like can be used as the heater 30. In FIG. 3, only the heater 30 arranged on one mounting surface 110 is shown for easy understanding of the drawing. FIG. 1 is a cross-sectional view taken along the II direction of FIG.

  Note that it is preferable to use an infrared heater that emits a wavelength that passes through the substrate 100 as the heater 30 in view of the substrate temperature overshoot. When an infrared heater having an infrared wavelength energy distribution is employed, the carbon plate can be efficiently heated. On the other hand, the absorption spectrum of the silicon substrate is 1000 nm or less. The present inventors have confirmed that the substrate 100 can be heated without overshooting by the radiation from the sample holder 10 made of carbon material, rather than the direct heating from the infrared heater.

  FIG. 4 shows the wavelength dependence of the absorption rate A and transmittance B of the silicon substrate and the radiation intensity C of the lamp heater. As shown in FIG. 4, in a silicon substrate used for a solar cell or the like, the absorptance A decreases and the transmittance B increases at a wavelength of 1000 nm or more. Therefore, as shown in FIG. 4, the sample holder 10 can be heated through the substrate 100 by adopting an infrared heater having a high radiation intensity C and a radiation wavelength of about 1300 nm to 2000 nm as the heater 30. Thereby, it can prevent that the board | substrate 100 becomes an overheating state and a characteristic deteriorates. As shown in FIG. 4, since the radiation intensity C becomes maximum near the wavelength of 1500 nm, an infrared heater having a radiation wavelength of 1500 nm is preferably used as the heater 30.

  According to the heating apparatus 1 shown in FIG. 1, by arranging the heater 30 between the substrates 100, the substrate 100 mounted on the sample holder 10 is uniformly heated. Furthermore, since the distance between the substrate 100 and the heater 30 is short compared to the case where the heater 30 is arranged only around the sample holder 10, the heating time can be shortened. The distance between the substrate 100 and the heater 30 is set to about 10 mm, for example. Moreover, by disposing the heater 30 around the sample holder 10, heat dissipation from the sample holder 10 is suppressed, and heating efficiency can be improved.

  A comparison between the heat treatment by the heating device 1A of the comparative example shown in FIG. 5 in which the heater 30A is arranged only around the sample holder 10 and the heat treatment by the heating device 1 shown in FIG. An induction heating (IH) heater using the principle of electromagnetic induction was used as the heater 30A of Comparative Example 1A. In addition, the following comparison was performed about the case where the heating apparatus 1 and the heating apparatus 1A are used for the preheating of a film-forming process.

  The result of the heat treatment by the heating device 1 and the heating device 1A is shown in FIG. The horizontal axis in FIG. 6 is the processing time, and the vertical axis is the substrate temperature of the substrate 100 to be processed. Note that the substrate 100 was heated in a vacuum state of about 5 Pa or less in the chamber 20. In FIG. 6, the substrate temperature T1 due to the heat treatment of the heating device 1 is indicated by a solid line, and the substrate temperature T2 due to the heat treatment of the heating device 1A is indicated by a broken line.

  When the heating apparatus 1 is used as a preheating apparatus for a processing apparatus such as a plasma enhanced chemical vapor deposition (CVD) film forming apparatus, the processing time required for a series of processes using the heating apparatus 1 and the processing apparatus is preliminarily “ It is often set as “specification”. For example, the specification of the time required to raise the substrate temperature from 200 ° C. to 450 ° C. is set to 53 seconds. On the other hand, as shown in FIG. 6, the time t required to raise the substrate temperature from 200 ° C. to 450 ° C. in the case of the heat treatment by the heating apparatus 1 is 41 seconds, which sufficiently satisfies the specifications. . During this time, the heating rate by the heating device 1 is 6.1 ° C./second, which satisfies the specification of 5.0 ° C./second or more. Further, the in-plane distribution of the substrate temperature of the substrate 100 at the start of film formation process t10 in the plasma CVD film formation apparatus is 490 ° C. to 505 ° C., and the temperature difference is 15 ° C. This satisfies the condition that the temperature difference is 22.5 ° C. or less when the specification is within 5%.

  In contrast, in the heat treatment by the heating apparatus 1A of the comparative example using the IH heater, the substrate temperature increased only to 250 ° C. in 53 seconds of the heating time specification. Further, when the film formation process was started at the timing when the substrate temperature was 450 ° C., the in-plane distribution of the substrate temperature at the start of the film formation process t20 was 310 ° C. to 440 ° C., and the temperature difference was as large as 130 ° C.

  As described above, it was confirmed that the heating apparatus 1 shown in FIG. 1 has a shorter heating time and a smaller in-plane distribution of the substrate temperature compared to the heating apparatus 1A of the comparative example. Furthermore, as shown in FIG. 6, it is confirmed that the substrate temperature overshoot is suppressed in the heat treatment by the heating apparatus 1, and a high-quality thin film with a small leakage current is formed together with the improvement of the temperature distribution. It was done.

  As described above, according to the heating apparatus 1 according to the first embodiment of the present invention, the heaters 30 are arranged between the substrates 100 so that the substrate 100 mounted on the boat-type sample holder 10 is even. The heating time can be suppressed.

(Second Embodiment)
With respect to the heating apparatus 1 shown in FIG. 1, the method of heating the substrate 100 by evacuating the chamber 20 has been described. In the heating apparatus 1 according to the second embodiment of the present invention, the substrate 100 is heated in a state where a gas is introduced into the chamber 20 so as to have a constant pressure. The gas introduced into the chamber 20 is, for example, nitrogen (N ₂ ) gas or air. Moreover, the pressure in the chamber 20 is set to 10,000 Pa or more. The inside of the chamber 20 may be at atmospheric pressure.

  For example, as shown in FIG. 7, the heating device 1 according to the second embodiment includes a gas introduction mechanism 40 and a gas discharge mechanism 50. The arrows shown in FIG. 7 indicate the flow of gas introduced into the chamber 20 and then exhausted. Other configurations are the same as those of the first embodiment shown in FIG.

  Specifically, after the sample holder 10 on which the substrate 100 is mounted is loaded into the chamber 20, the inside of the chamber 20 is evacuated by the gas discharge mechanism 50. Thereafter, the gas introduction mechanism 40 introduces a predetermined gas, for example, nitrogen gas, into the chamber 20 until a predetermined pressure is reached. In the chamber 20, the substrate 100 is heated by the heater 30 in a nitrogen atmosphere. After heating the substrate 100 for a predetermined time until the substrate 100 reaches a desired temperature, the heating of the substrate 100 is finished. Thereafter, the nitrogen gas in the chamber 20 is exhausted by the gas exhaust mechanism, and the heating process of the substrate 100 is completed.

  Note that the substrate 100 may be heated in a state in which air is introduced into the chamber 20 to be at atmospheric pressure. In this case, the gas introduction mechanism 40 and the gas discharge mechanism 50 may not be installed in the heating device 1.

  By filling the chamber 20 with gas, the heat radiated from the heater 30 is more efficiently conducted to the substrate 100 than in a vacuum, and the heating time of the substrate 100 can be shortened. In addition, since the heater 30 is disposed in the immediate vicinity of the substrate 100, the substrate 100 can be uniformly heated faster than it is heated in a vacuum state due to heat transfer by convection of the gas in the chamber 20.

  In order to improve the temperature uniformity of all the substrates 100 mounted on the sample holder 10, it is preferable to cover the periphery of the sample holder 10 with a heat insulating material. FIG. 8 shows an example in which the periphery of the sample holder 10 is covered with a heat insulating material 60 arranged on the inner wall of the chamber 20. For the heat insulating material 60, for example, a gypsum material or carbon felt can be used.

  FIG. 9 shows changes in the temperature of the substrate plate 11 of the sample holder 10 and the substrate 100 disposed on the substrate plate 11 heated by the heating device 1. In FIG. 9, symbols P <b> 1 to P <b> 3 are temperatures at the upper part, the central part, and the lower part of the substrate plate 11. Reference numerals S <b> 1 to S <b> 4 are temperatures at the center of the back surface, the bottom of the back surface, the center of the front surface, and the top of the surface. The surface facing the heater 30 was the surface of the substrate 100. As the heater 30, an infrared heater that emits a wavelength that passes through the substrate 100 was used. Further, air was introduced into the chamber 20 to heat the substrate 100.

  As shown in FIG. 9, the temperature difference between each position of the substrate plate 11 and each position of the substrate 100 is small even when 10 minutes have passed since the start of heating. That is, the substrate 100 is not overheated. Further, the temperature difference at each position of the substrate 100 is within about 20 ° C. Therefore, it has been confirmed that the temperature distribution of the substrate 100 is uniform and does not enter an overheated state until at least 10 minutes of the heat treatment time by the heating apparatus 1 elapses.

  The heating device 1 can also be used as a heating device for preheating of, for example, an inline film forming apparatus. For example, in the film formation process of the solar cell antireflection film, the film is formed on the substrate 100 in a state where the temperature of the substrate 100 to be processed is set to a predetermined temperature. For this reason, in the case where a film formation process is performed using an in-line film formation apparatus, the substrate 100 is preheated before being carried into the film formation chamber of the film formation apparatus. Then, the substrate 100 that has reached the set temperature is carried into the film formation chamber and a film formation process is performed.

  FIG. 10 shows an example of an in-line film forming apparatus including two chambers, a heating apparatus 1 and a film forming apparatus 2. The substrate 100 mounted on the sample holder 10 stored in the heating apparatus 1 is preheated to a predetermined temperature by the heater 30. Thereafter, the sample holder 10 is transferred to the film forming apparatus 2 by the transfer apparatus 3, and a thin film is formed on the substrate 100 in the film forming apparatus 2.

  When a film forming process is performed by an inline film forming apparatus using a plurality of sample holders 10, the substrate 100 to be subjected to the next film forming process is heated while the film forming process is performed on the substrate 100 in the film forming apparatus 2. The apparatus 1 can be preheated. In other words, by preheating the substrate 100 during the waiting time of the film formation process, the throughput of the in-line film formation apparatus is improved.

  In addition, when the substrate 100 is stored in the film forming apparatus 2 in a state where the substrate 100 has already been heated, for example, at atmospheric pressure by the heating apparatus 1, when the substrate 100 is heated in a vacuum state before film formation in the film forming apparatus 2. The substrate temperature at the start of heating is high. For this reason, it is possible to shorten the heating time in a vacuum state where it is difficult to raise the temperature. The experiment confirmed that the substrate temperature increased from 150 ° C. to 250 ° C. in 50 seconds in the film forming apparatus 2 by preheating.

  FIG. 11 shows the result of measuring the carrier lifetime for a film formed on the substrate 100 by an in-line film forming apparatus using the heating apparatus 1 as a preheating apparatus. The carrier lifetime was measured when no preheating was performed and when 300 ° C preheating was performed at atmospheric pressure. Note that “no annealing” in FIG. 11 is a case where only the film formation is performed without heating the substrate 100 in the film formation apparatus 2, and “with annealing” is a case where the substrate is formed in the film formation apparatus 2 before film formation. In this case, 100 is heated to 700 ° C. The carrier lifetime was measured by the μ-PCD method for measuring the amount of carriers generated in the sample irradiated with the laser.

  As shown in FIG. 11, it was confirmed that the carrier live time was improved by the preliminary heating at least up to 300 ° C. regardless of the presence or absence of annealing in the film forming apparatus 2. Note that it is considered that the carrier lifetime is shortened when the substrate 100 is overheated.

  The movement of the sample holder 10 between the heating apparatus 1 and the film forming apparatus 2 is performed by, for example, raising the chamber 20 of the heating apparatus 1 or the film forming chamber of the film forming apparatus 2 or lowering the sample holder 10. It carries out in the state which took out the sample holder 10 from the chamber. Alternatively, an openable / closable gate may be installed between the heating apparatus 1 and the film forming apparatus 2 and the sample holder 10 may be moved through the gate.

  FIG. 10 shows an example of an in-line type film forming apparatus including the heating apparatus 1 and the film forming apparatus 2. However, an in-line type apparatus other than the film forming apparatus, for example, an etching apparatus or an ashing apparatus and the heating apparatus 1 is configured. May be. Moreover, although the example of the in-line type apparatus which consists of two chambers was shown above, you may use the heating apparatus 1 for the in-line type apparatus comprised from three or more rooms.

  As described above, according to the heating apparatus 1 according to the second embodiment of the present invention, the substrate 100 can be uniformly heated in a short time. Furthermore, the heating time of the substrate 100 in the processing apparatus after the preheating can be shortened by using the heating apparatus 1 as the preheating apparatus of the inline processing apparatus. Others are substantially the same as those in the first embodiment, and redundant description is omitted.

  As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Heating apparatus 2 ... Film-forming apparatus 3 ... Conveyance apparatus 10 ... Sample holder 11 ... Substrate plate 12 ... Bottom plate 20 ... Chamber 30 ... Heater 40 ... Gas introduction mechanism 50 ... Gas discharge mechanism 60 ... Heat insulation material 100 ... Substrate 110 ... Installation surface

Claims (6)

A heating device for heating a substrate mounted on the mounting surface of a sample holder having a configuration in which a plurality of substrate plates each having a mounting surface are arranged in parallel in a surface normal direction of the mounting surface,
A chamber in which the sample holder is stored;
A heating device comprising: a heater disposed around the sample holder and between the substrate plates in the chamber.   The heating apparatus according to claim 1, wherein the heater is an infrared heater that emits a wavelength that passes through the substrate, and the substrate is heated by heat conducted through the sample holder heated by the heater. .   The heating apparatus according to claim 1 or 2, wherein the inside of the chamber is set to a pressure of 10,000 Pa or more and the substrate is heated.   The heating apparatus according to claim 3, wherein air is introduced into the chamber and set to atmospheric pressure. A gas introduction mechanism for introducing nitrogen gas into the chamber;
The heating apparatus according to claim 3, further comprising: a gas discharge mechanism that sets a pressure in the chamber by discharging the nitrogen gas from the chamber, and heating the substrate in a nitrogen atmosphere. .   The heating apparatus according to claim 1, wherein an inner wall of the chamber is covered with a heat insulating material.

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