JP2013187314A - In-line type plasma cvd apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-line type plasma CVD apparatus with a simple structure, capable of uniformly heating a number of substrates.SOLUTION: A plurality of Si substrates 12 placed on a plate 11 made of graphite carbon are introduced into a pre-heating chamber 2 of the in-line type plasma CVD apparatus, and the substrates 12 are heated by a plurality of top lamp heaters 14 arranged above the substrates 12 and a plurality of bottom lamp heaters 15. All the top lamp heaters 14 face the same direction and are arranged in parallel, and all the bottom lamp heaters 15 face the same direction and are arranged in parallel. The top lamp heaters 14 and the bottom lamp heaters 15 are orthogonal to each other.

Description

  In the present invention, a large number of substrates on a plate are placed in a load chamber together with the plate, evacuated, and then sequentially moved to a preheating chamber, a film formation chamber, and an unload chamber, and then brought to an atmospheric atmosphere in the unload chamber. The present invention relates to an in-line type plasma CVD apparatus that collects a substrate after film formation, and relates to an in-line type plasma CVD apparatus that improves the uniformity of heating in a preheating chamber.

  A plasma CVD (chemical vapor deposition) apparatus is a semiconductor device in which a silicon nitride film (SiNx film) is formed on a Si substrate to produce a solar cell and various semiconductor layers are formed on the Si substrate. Is often used in the manufacture of This plasma CVD apparatus supplies a source gas to the substrate atmosphere in a state where the substrate is heated to, for example, 500 ° C. in a vacuum, and generates a plasma discharge between the electrode and the substrate to ionize the source gas. After that, a desired film is formed by depositing predetermined components on the substrate. As this plasma CVD apparatus, the substrate is loaded into the load chamber from the atmosphere, and the substrate is placed in a vacuum atmosphere by vacuum suction in the load chamber. Proposal of an inline type plasma CVD apparatus that moves the substrate from the heating chamber to the deposition chamber, moves the deposited substrate to the unload chamber, and places the unloaded chamber in the atmosphere to take out the deposited substrate. (Patent Document 1). As described above, since the substrate can be heated and formed in a series of steps without breaking the vacuum, the in-line type plasma CVD apparatus has an advantage of high throughput.

JP 2010-159463 A

  However, the inline-type plasma CVD apparatus disclosed in Patent Document 1 has the following problems. The deposition quality of the plasma CVD film strongly depends on the uniformity of the substrate temperature during the deposition. For example, when manufacturing a solar cell, a large number of Si substrates (hereinafter referred to as substrates) are placed on a plate, and the plate is loaded into a preheating chamber to heat the substrate. It is necessary to heat so that the temperature of all the substrates on the plate is constant and the temperature is uniform in each substrate. Therefore, in Patent Document 1, a flat heater is disposed below the substrate in the preheating chamber so as to be movable up and down, and the lamp heater is fixed to the ceiling so as to hang from the ceiling of the chamber above the substrate. The substrate is heated from above and below the substrate. At this time, as the lower flat heater, a resistance heating type flat heater having an area substantially the same as the back surface area of the substrate tray (plate) is used, and this resistance heating type is used to efficiently heat the substrate. The substrate is heated in a state where the flat heater is raised and brought into contact with the back surface of the substrate.

  For this reason, the plasma CVD apparatus disclosed in Patent Document 1 requires a driving means for moving the heater up and down, and there is a problem that the apparatus becomes large.

  The present invention has been made in view of such problems, and an object thereof is to provide an in-line plasma CVD apparatus capable of uniformly heating a large number of substrates with a simple apparatus.

An in-line type plasma CVD apparatus according to the present invention includes a load chamber and an unload chamber that can be opened to the atmosphere and vacuum suction, a preheating chamber that heats the internal charge in a vacuum state, and an internal charge. A film forming chamber for forming a film by plasma CVD in a vacuum state,
After the plate on which a plurality of substrates are placed is evacuated in the load chamber, the substrate on the plate is heated by being inserted into the preheating chamber while maintaining this vacuum state, While maintaining the vacuum state, the film is inserted into the film formation chamber and formed on the substrate on the plate by plasma CVD. After being released from the vacuum state to the atmosphere in the unload chamber, the film is formed on the plate. In an in-line type plasma CVD apparatus from which the substrate is taken out,
In the heating chamber, a plurality of straight tubular upper lamp heaters arranged parallel to each other at a distance so as to be parallel to the plate as a whole above the plate on which the substrate is placed; Below the plate, a plurality of straight tubular lower lamp heaters arranged in parallel and spaced from each other so as to be parallel to the plate as a whole are provided, the upper lamp heater and the lower lamp heater Are arranged so that their longitudinal directions are orthogonal to each other,
The upper lamp heater is arranged more densely than the lower lamp heater.

  In this case, two film forming chambers are arranged in series, and different types of films can be formed in each film forming chamber.

  The upper lamp heater is divided into a plurality of groups with respect to a direction perpendicular to the longitudinal direction of the upper lamp heater, and the temperature is controlled by adjusting the current for each group. The lower lamp heater is controlled by the lower lamp heater. It is preferable to divide into a plurality of groups with respect to the direction perpendicular to the longitudinal direction, and to control the temperature by adjusting the current for each group.

  According to the present invention, the substrate is heated by the lamp heater from both above and below the substrate. In this way, since the substrate is heated by the lamp heater, even if the substrate is separated from the substrate, the substrate can be sufficiently heated by the radiant heat, and a large-scale device that moves the heater up and down to contact the plate Is unnecessary.

  In the present invention, the plurality of substrates on the plate are heated mainly by the upper lamp heater that heats the substrate from above the substrate. However, the substrate is supplementarily heated by the lower lamp heater from below the substrate. By doing so, the uniformity of heating of the substrate is improved. In other words, the lower lamp heater eliminates the variation in temperature distribution in which the temperature is high immediately below the heater of the upper lamp heater and the temperature is low at the position between the heaters. At this time, the upper lamp heater that heats the substrate from the upper side of the substrate and the lower lamp heater that heats the substrate from the lower side of the substrate are arranged so that the longitudinal directions thereof are orthogonal to each other. Is a wave perpendicular to the longitudinal direction of the upper lamp heater, but the variation in temperature distribution of the lower lamp heater is a wave perpendicular to the longitudinal direction of the lower lamp heater. Since they are orthogonal to each other, it is possible to uniformly heat the plate by canceling variations in temperature distribution. Therefore, the substrate on the plate can be heated uniformly regardless of the position on the plate, which contributes to uniform film formation quality in the subsequent film formation process.

It is a block diagram which shows the in-line type plasma CVD apparatus of embodiment of this invention. It is a figure which shows the internal structure of a preheating chamber. It is a top view which shows arrangement | positioning of a lamp heater.

  Hereinafter, embodiments of the present invention will be specifically described with reference to attached drawings. As shown in FIG. 1, the in-line type plasma CVD apparatus inserts a film formation target into the load chamber 1 under the atmosphere, seals the inside, and then vacuums the inside of the load chamber 1 to form a film. Vacuum the object. Thereafter, the film formation target is moved to the preheating chamber 2 as it is without breaking the vacuum state, and the film formation target is heated in the preheating chamber 2 so that the SiN film is formed on the Si substrate. In the case of film formation, the substrate is heated to about 500 ° C. in the preheating chamber 2.

  Thereafter, the film formation target is moved into the film formation chamber 2 and loaded, and the film formation gas is supplied into the chamber and the film formation target is heated while the film formation target is heated. A plasma discharge is generated between the object and the electrode to ionize the film forming gas. Thereby, a desired film is deposited on a film formation target such as a substrate. Thereafter, the film formation target after film formation is moved from the film formation chamber 3 to the unload chamber 4 while being kept in a vacuum state, and the unload chamber 4 and the film formation chamber 3 are shut off. Thereafter, the unload chamber 4 is opened to atmospheric pressure, and the film formation target after film formation is taken out. Thus, in the in-line type plasma CVD apparatus, the substrate is heated and formed in a series of steps without breaking the vacuum.

  In the preheating chamber 2, as shown in FIG. 2, for example, a plurality of Si substrates 12 constituting, for example, a solar battery cell are placed on a graphite carbon plate 11. The plate 11 has a size of, for example, about 1500 mm × 1100 mm. On the plate 11, for example, a Si substrate 12 having a size of, for example, 156 mm × 156 mm is equally spaced at a matrix position of, for example, 6 rows and 9 columns. Are placed under certain rules.

  The plate 11 is conveyed into the preheating chamber 2 on the pulley 13. A plurality of upper lamp heaters 14 are arranged above the plate 11 stopped at a predetermined position in the preheating chamber 2 so that the longitudinal direction thereof is perpendicular to the paper surface. Below the plate 11, a plurality of lower lamp heaters 15 are arranged so that the longitudinal direction thereof is parallel to the paper surface. A distance between the upper lamp heater 14 and the lower lamp heater 15 and the substrate 12 on the plate 11 is, for example, 40 to 50 mm. The lamp heaters 14 and 15 are, for example, infrared lamp heaters, and the diameter thereof is, for example, 15 mm. The lengths of the lamp heaters 14 and 15 are determined by the size of the inside of the preheating chamber 2 or the size of the plate 11, but the arrangement density of the upper lamp heaters 14 is higher than that of the lower lamp heaters 15. is there. The number of the upper lamp heater 14 and the lower lamp heater 15 differs depending on the ultimate temperature of heating and the level of uniformity of the temperature distribution, and can be set as appropriate.

  In FIG. 3, the upper lamp heater 14 is indicated by a solid line, and the lower lamp heater 15 is indicated by a broken line. As shown in FIG. 3, the upper lamp heater 14 is divided into, for example, three groups (indicated by a two-dot chain line), and each group is connected in parallel to a terminal 16. It is connected to the. Accordingly, the upper lamp heater 14 is divided into three groups, and the temperature is controlled by adjusting the current for each group. The lower lamp heater 15 is also divided into, for example, three groups (similar to a two-dot chain line), and each group is connected in parallel to the terminal 18, and is connected to the power supply device from the terminal 18 through the lead 19. . Thus, the lower lamp heater 15 is divided into three groups, and the temperature is controlled by adjusting the current for each group. The temperature control of the upper lamp heater 14 and the lower lamp heater 15 is performed by adjusting and setting the current for each group so that a uniform temperature distribution can be obtained on the plate 11.

  Then, for example, the substrate 12 on the plate 11 that has been uniformly heated to a predetermined set temperature of 400 to 500 ° C. is transferred to the film forming chamber 3, and the substrate is further heated in the film forming chamber 3. While maintaining the temperature at a predetermined temperature, plasma discharge is generated between the electrodes and the source gas supplied into the film forming chamber 3 is ionized to form, for example, a SiN film on the substrate.

  Next, the operation of the inline type plasma CVD apparatus configured as described above will be described. In the plasma CVD apparatus, the improvement in film formation quality is largely due to the uniformity of the substrate temperature. In the present invention, in the preheating chamber 2, the substrate 12 on the plate 11 is heated from above by the upper lamp heater 14 and from below by the lower lamp heater 15, but at an appropriate length interval. Although it is unavoidable that the heating by the arranged lamp heater fluctuates in the direction parallel to the surface of the plate, in the present invention, the wavy temperature distribution by the upper lamp heater 14 and the wavy temperature distribution by the lower lamp heater 15. Since the direction of the change is orthogonal, the fluctuations in the temperature distribution cancel each other. As a result, the substrate 12 on the plate 11 is uniformly heated regardless of the mounting position on the plate 11, and the temperature change between the substrates 12 is extremely small. Also, the temperature distribution in each substrate 12 is extremely small.

  Therefore, according to the present invention, the substrate can be uniformly heated in the preheating chamber 2, and a desired film such as a SiN film can be uniformly formed on the substrate 12 in the film forming chamber 3 in a later process. At the same time, the film formation quality can be improved.

1: Load chamber 2: Preheating chamber 3: Film formation chamber 4: Unload chamber 11: Plate (made of graphite carbon)
12: Substrate (Si substrate)
13: Pulley 14; Upper lamp heater 15: Lower lamp heater 16, 18: Terminals 17, 19: Lead

Claims (3)

A load chamber and an unload chamber capable of opening the atmosphere to the atmosphere and vacuum suction, a preheating chamber for heating the internal charge in a vacuum state, and forming a film on the internal charge by plasma CVD in a vacuum state A deposition chamber;
After the plate on which a plurality of substrates are placed is evacuated in the load chamber, the substrate on the plate is heated by being inserted into the preheating chamber while maintaining this vacuum state, While maintaining the vacuum state, the film is inserted into the film formation chamber and formed on the substrate on the plate by plasma CVD. After being released from the vacuum state to the atmosphere in the unload chamber, the film is formed on the plate. In an in-line type plasma CVD apparatus from which the substrate is taken out,
In the heating chamber, a plurality of straight tubular upper lamp heaters arranged parallel to each other at a distance so as to be parallel to the plate as a whole above the plate on which the substrate is placed; Below the plate, a plurality of straight tubular lower lamp heaters arranged in parallel and spaced from each other so as to be parallel to the plate as a whole are provided, the upper lamp heater and the lower lamp heater Are arranged so that their longitudinal directions are orthogonal to each other,
The in-line type plasma CVD apparatus, wherein the upper lamp heater is arranged more densely than the lower lamp heater. The in-line type plasma CVD apparatus according to claim 1, wherein two film forming chambers are arranged in series, and different types of films are formed in each film forming chamber. The upper lamp heater is divided into a plurality of groups with respect to the direction perpendicular to the longitudinal direction of the upper lamp heater, and the temperature is controlled by adjusting the current for each group. The lower lamp heater is controlled in the longitudinal direction of the lower lamp heater. The in-line type plasma CVD apparatus according to claim 1 or 2, wherein the temperature is controlled by adjusting a current for each group divided into a plurality of groups with respect to a direction perpendicular to the direction.

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