JP2010189757A - Thin film production method and thin film production device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film production method and a thin film production device by which unideposit film deposition can be perdeposited so as to achieve quality control. <P>SOLUTION: In the thin film production method, a thin film deposition means, by which two or more kinds of thin films are selectively deposited on the main face of the substrate S while feeding the substrate S from either of the first substrate storage means 1 or the second substrate storage means 2 to the other, is arranged between a first substrate storage means 1 and a second substrate storage means 2 each storing a belt-like substrate, and the feeding direction of the substrate S is reversed for every time of depositing one layer of the thin films, further, the kind of the thin films is changed, and two or more kinds of thin films are successively laminated on the main face. The substrate storage means 1, 2 are provided with detection parts 7A, 7B detecting the thin film deposited on the belt-like substrate S, a film quality evaluation calculating part 8 where the film quality of the thin film detected by the detection parts 7A, 7B is evaluated, and a suitable interelectrode spacing is calculated is provided, and the interelectrode is controlled by an interelectrode command control part 9 by the calculated result of the film quality evaluation calculating part 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a thin film manufacturing method and a thin film manufacturing apparatus capable of controlling film spacing by evaluating film quality.

  Conventionally, a roll-to-roll type plasma CVD apparatus as shown in FIG. 4 is known as a so-called CVD apparatus for continuously forming a thin film layer of an amorphous solar cell. This CVD apparatus includes a roll preparation chamber 10A and a roll removal chamber 10B on the left and right sides, and forms N-type, I-type, and P-type thin film layers along the substrate S sent out from the roll preparation chamber 10A. The film forming chambers 11A to 11C for performing the above are arranged.

  In each of the film forming chambers 11A to 11C, a ground electrode 30A and a high frequency electrode 30B are arranged, and a reactive gas introduced into the film forming chambers 11A to 11C from the introduction port 30C is excited by a high frequency electric field formed between these electrodes. To a plasma state. Unnecessary gas after the reaction is exhausted to the outside through the exhaust port 30D. A reactive gas is introduced into each of the film forming chambers 11A to 11C according to the type of thin film layer to be formed.

  When the conventional apparatus is used to stack the N-type layer, the I-type layer, and the P-type thin film layer in this order on the main surface of the substrate S, N layers are sequentially formed from the film formation chamber close to the roll preparation chamber 10A. A reaction gas for forming the mold layer, the I-type layer, and the P-type layer is introduced. Then, the substrate stored in the roll preparation chamber 10A is sent out, and first passes through the film formation chamber 11A for forming the N-type amorphous silicon layer. The substrate region on which the N-type layer is formed is then led to the film formation chamber 11B for forming the I-type layer, and is laminated on the previous N-type layer to form the I-type layer. The substrate region where the N-type layer and the I-type layer are laminated is then led to the film formation chamber 11C for forming the P-type layer, and is laminated on the previous N-type layer to form the P-type layer. Be filmed. As described above, the N-type layer, the I-type layer, and the P-type layer are sequentially stacked.

However, according to this conventional apparatus, three film forming chambers are required to form the N-type layer, I-type layer, and P-type thin film layer. Requires a membrane chamber. For this reason, when the number of stacked layers increases, the size of the device increases and the cost of the device increases.
As described above, film formation for forming a conventional solar cell is a multi-chamber, separate vacuum process, and it is difficult to evaluate a thin film for each single film, and the evaluation result is fed back to film formation conditions. As a result, the stability of production declined and the yield decreased, and countermeasures were required.

  Therefore, one film forming chamber is provided between the first roll substrate storage chamber and the second roll substrate storage chamber storing the roll substrate, and the feeding direction of the belt-shaped roll substrate is reversed, so that the types are different. A prior art in which a thin film is formed is known (see Patent Document 1).

  However, according to this prior art, when the feed direction of the roll substrate is sent out from the first roll substrate storage chamber and when the roll substrate is sent out from the second roll substrate storage chamber, the roll substrate is sent out at the same speed and under the same conditions. For this reason, unevenness occurs in the film quality depending on the conditions of the film forming chamber, resulting in a decrease in quality control.

Japanese Patent Laid-Open No. 10-22518

In order to increase the efficiency of solar cells, solar cells using a microcrystalline silicon film that spreads light in the long wavelength region are being put into practical use. In the solar cell using the microcrystalline silicon film, the thickness of the microcrystalline silicon film is increased, and the number of laminated layers is increased, so that the total thickness of the film forming the solar cell is about 7 compared to the conventional solar cell. The film is peeled off from the electrode due to the film stress, which affects the quality of the solar cell. Thus, the maintenance of an electrode is mentioned as the subject of the film-forming apparatus which manufactures a solar cell. In electrode maintenance, the film thickness of the film attached to the electrode is usually 200 μm, and electrode replacement and film removal work is performed using this value as a guide. The operating rate depends on this frequency, and ultimately the production capacity is affected. Affect. For this reason, in many cases, the number of electrodes is increased or expanded as means for increasing the production capacity. For this reason, there is a problem that the footprint of the apparatus is increased and the apparatus cost is increased. There is also dry cleaning as a technique for increasing the operating rate. Dry cleaning is a method in which a reactive gas is introduced into plasma without being exposed to the atmosphere, and etching is performed to remove a film attached to an electrode. Although there is an advantage that the electrode can be used continuously while maintaining a vacuum, the reaction gas used for dry cleaning is highly dangerous from the viewpoint of safety, and from the environmental point of view, the burden on the global environment is large. There is a problem that the cost of preventive incidental equipment increases.
The present invention can detect the film quality of the roll substrate formed in the film formation chamber, evaluate the film quality, control the electrode spacing in the film formation chamber, and perform uniform film formation to improve quality control. An object of the present invention is to provide a thin film manufacturing method and a thin film manufacturing apparatus.

In order to solve the above problems, the present invention provides a first substrate storage means for storing one end side of a belt-like substrate and a second substrate storage means for storing the other end side of the belt-like substrate. A thin film forming means for selectively forming one of a plurality of types of thin films on the main surface of the substrate while feeding the substrate from one of the first substrate storage means and the second substrate storage means toward the other. In the thin film manufacturing method in which the plurality of types of thin films are sequentially stacked on the main surface by reversing the feeding direction of the substrate every time one layer of the thin film is formed and changing the type of the thin film, formed on the belt-shaped substrate A detection unit for detecting the thin film is provided in the substrate storage means, a film quality evaluation calculation unit for evaluating the film quality of the thin film detected by the detection unit and calculating an appropriate electrode interval is provided. Calculate the electrode spacing from the calculation result. It is to control the spacing command control unit.
Further, the present invention is to form a thin film by controlling a film forming gas amount and / or input power in a film forming chamber of the thin film forming means from a calculation result of the film quality evaluation calculating unit.
In the present invention, the chamber between the film forming chamber constituting the thin film forming means and the storage chamber constituting the first and second substrate storage means is partitioned by a partition valve, and is unwound from the storage chamber or stored. The pressure in the first and second storage chambers is maintained in a vacuum by passing the substrate while bringing the partition valve into close contact with the substrate wound in the chamber.
Furthermore, the present invention provides a first substrate storage means for storing one end side of the belt-shaped substrate,
Second substrate storage means for storing the other end side of the belt-shaped substrate;
Between the first substrate storage means and the second substrate storage means, a pair of electrodes facing each other are built in and arranged from one of the first substrate storage means and the second substrate storage means. A thin film forming means for selectively forming one of a plurality of types of thin films on a main surface of the substrate by forming a plasma state by discharging between the electrodes while feeding the substrate toward the other; In the thin film manufacturing apparatus, the plurality of types of thin films are sequentially stacked on the main surface by reversing the substrate feeding direction and changing the type of thin film each time the substrate is formed. Each of the means and the second substrate storage means is provided with a detection unit for detecting a thin film, a conveyance path for guiding the belt-like substrate is provided so as to be close to the detection unit at a fixed interval, and a pair arranged in these conveyance paths is provided. Between eggplant rollers A detection roller that changes the feeding direction is arranged, and the film quality is evaluated based on a signal from the detection unit, and a film quality evaluation calculation unit that calculates an appropriate electrode interval is provided. Based on the signal from the film quality evaluation calculation unit An electrode interval command control unit for controlling the electrode interval is provided.
Furthermore, an electrode moving mechanism for adjusting the distance between the electrodes is provided.
In addition, a partition valve is provided on a partition wall that partitions between the film forming chamber constituting the thin film forming means and the storage chamber constituting the first and second substrate storage means, and is unwound from the storage chamber, Alternatively, the partition valve is brought into close contact with the substrate wound up in the storage chamber to maintain the pressure in the storage chamber.

According to the first aspect, the thin film formed on the belt-like substrate is detected by the detection unit, and the film quality of the thin film can be evaluated, so that the electrode interval can be controlled, so that the manufacturing efficiency is improved and the yield is improved. can do.
According to the second aspect, since the thin film is formed by controlling the amount of film forming gas and / or input power in the film forming chamber, uniform film formation can be manufactured and quality control can be improved. Can do.
According to the third aspect, the pressure in the storage chamber can be maintained in a vacuum state.
According to the fourth aspect, since an appropriate electrode interval is calculated by the film quality evaluation calculation unit and the electrode interval is controlled by the electrode interval command control unit, uniform film formation can be manufactured, and quality control is improved. Can be achieved.
According to the fifth aspect, since the distance between the electrodes can be adjusted by the electrode moving mechanism, the distance between the electrodes can be easily adjusted.
According to the sixth aspect of the present invention, since the partition valve is provided on the partition wall that partitions the storage chamber and the film forming chamber constituting the first and second substrate storage means, The atmospheric pressure can be maintained.

It is a conceptual diagram which shows the thin film manufacturing apparatus by this invention. It is a figure which shows the relationship between a Raman peak intensity ratio and the distance between electrodes. It is a conceptual diagram which shows the thin film manufacturing apparatus by other embodiment of this invention. It is a conceptual diagram which shows the conventional thin film manufacturing apparatus which has several film-forming chambers.

  A detection unit for detecting the thin film formed on the belt-shaped substrate is provided in the substrate storage chamber, a film quality evaluation calculation unit for evaluating the film quality of the thin film detected by the detection unit and calculating an appropriate electrode interval is provided. The electrode interval is controlled by the electrode interval command control unit from the calculation result of the evaluation calculation unit.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 is a conceptual diagram showing a thin film manufacturing apparatus. Roll substrate storage chambers 1 and 2 (first and second substrate forming means) for storing one end side and the other end side of a belt-like substrate, and the roll substrate storage. A film forming chamber 3 (thin film forming means) disposed between the chambers 1 and 2;

  The roll substrate storage chamber 1 includes a roller 1A that winds one end of the substrate S in a roll shape and pivotally supports it, and a guide roller 1B that guides the substrate wound around the roller 1A to the outside. Similarly, the roll substrate storage chamber 2 includes a roller 2A that winds the other end of the substrate S in a roll shape and supports it, and a guide roller 2B for guiding the roller 2A to the outside.

  The film formation chamber 3 is arranged so as to face the common installation electrode 3A across the common installation electrode 3A with a built-in heater and the substrate S sent out from one of the roll substrate storage chambers 1 and 2 to the other. A high-frequency electrode 3B, a guide roller 3C for guiding the substrate S to be positioned in the vicinity of the common installation electrode 3A, a gas introduction pipe 3D for introducing a reaction gas into the film forming chamber 3, and An exhaust pipe 3E for exhausting and a deposition preventing plate 3F that guides the reaction gas introduced from the introduction pipe 3D and prevents vapor deposition on other than the substrate S are configured.

  When the reaction gas is introduced into the film forming chamber 3 through the gas introduction pipe 3D, the reaction gas is heated by a heater built in the common installation electrode 3A, and the high frequency electrode 3B and the common installation electrode 3A are heated. Excited by a high-frequency electric field between them and a plasma state. And each component of the reactive gas which became the plasma state reacts, it vapor-deposits on a board | substrate, and forms a thin film into a film. The type of thin film to be formed is determined by the type of reaction gas introduced. The high-frequency electrode 3B is provided with an electrode moving mechanism 6 that moves the electrode in the front-rear direction, and is configured such that the distance to the common electrode 3A can be adjusted.

  In the roll substrate storage chamber 1, one detection roller 4 </ b> A and two auxiliary rollers 4 </ b> B are formed in a triangular shape as an example in the present embodiment in the conveyance path of the substrate S between the guide roller 1 </ b> B and the guide roller 3 </ b> C. It is placed at the vertex position. The detection roller 4A is located between the two auxiliary rollers 4B arranged along the conveyance path, and is arranged so as to be greatly protruded and bent in a direction orthogonal to the conveyance direction of the substrate S.

  Similarly, the roll substrate storage chamber 2 is provided with one detection roller 5A and two auxiliary rollers 5B that make a pair in the conveyance path of the substrate S between the guide roller 3C and the guide roller 2B. In the example, it is arranged at the position of a triangular vertex as an example. The detection roller 5A is located between a pair of auxiliary rollers 5B arranged along the transport path, and changes the transport direction of the substrate S with respect to the transport direction of the substrate S. The detection roller 5A is disposed so as to protrude greatly in the orthogonal direction.

The roll substrate storage chamber 2 is provided with a monitor (detection unit) 7A for detecting the quality of the thin film formed on the main surface of the substrate S corresponding to the detection roller 5A. A monitor (detection unit) 7B for detecting the quality of the thin film formed on the main surface of the substrate S corresponding to the detection roller 4A is disposed.
In the film forming chamber 3, many powdery reaction products are generated at the time of film forming, and the sensors of the monitors 7A and 7B are contaminated, which may affect the evaluation. The monitor 7B is disposed in the monitor 7B and the roll substrate storage chamber 2.
The monitors 7A and 7B are both installed directly in a vacuum and installed on the atmosphere side via a viewing port.
There is a concern that the substrate S vibrates during continuous conveyance, and it is assumed that the outputs of the monitors 7A and 7B fluctuate due to this influence. Therefore, the measurement is performed with the substrate S held by the detection roller 4A and the detection roller 5A. Do.

  A film quality evaluation calculation unit 8 is connected to the monitors 7A and 7B, and calculates the film quality based on the outputs sent from the monitors 7A and 7B.

  The output signal from the film quality evaluation calculation unit 8 is sent to the electrode interval command control unit 9, and the electrode interval command control unit 9 operates the electrode (front-rear) moving mechanism 6.

  Next, the thin film manufacturing method of the present invention will be described.

The substrate S wound around the roller 1A passes between the common ground electrode 3A and the high frequency electrode 3B, and a thin film is formed on the main surface of the substrate S.
Since the substrate S is continuously conveyed from the roller 1A to the roller 2A, the film can be continuously formed on the main surface of the substrate S and the conveying direction.
The forward rotation of continuous conveyance refers to the delivery of the substrate S from the roller 1A to the roller 2A, and the reverse rotation refers to the delivery of the substrate S from the roller 1A to the roller 2A.
The first film to be laminated is formed by continuously transporting the substrate S from the roll substrate storage chamber 1 to the roll substrate storage chamber 2 in the normal rotation direction.
The first film formed is evaluated before being wound around the roller 1A, and a single film is evaluated.

The second film is formed by continuously transporting the substrate S from the roll substrate storage chamber 2 to the roll substrate storage chamber 1 in the reverse direction.
Since the evaluation is also performed at this time, the film can be evaluated for each of the normal rotation and the reverse rotation by performing the evaluation before winding the roller 2A, and quality control can be performed for each lamination stage.
The positions of the monitors 7A and 7B in this embodiment are set in the roll substrate storage chamber 2 in the forward rotation direction and in the roll substrate storage chamber 1 in the reverse rotation direction.

The thin film evaluation of this example is a thin film manufacturing apparatus assuming a microcrystalline silicon film, and there is a crystallization rate as one guideline for film management.
The microcrystalline silicon film is a thin film in which microscopic crystals and amorphous regions are mixed.
As a method for evaluating the crystallization rate of a microcrystalline silicon film, for example, an evaluation method using a Raman peak intensity ratio by Raman spectroscopy is known. In the case of a microcrystalline silicon film used for a solar cell, it is determined according to the required quality. For example, the evaluation is performed based on whether or not the measured value of the Raman peak intensity ratio is within this appropriate range.
The thin film manufacturing apparatus of this embodiment can perform thin film evaluation for each single film, measure the Raman peak intensity ratio, and feed back to the film forming conditions, thereby improving manufacturing efficiency and yield.
The film quality monitors 7A and 7B of this example used Raman spectroscopy as a detection method.

FIG. 2 shows the relationship between the Raman peak intensity ratio and the distance between the electrodes.
It has been found that the Raman peak intensity ratio changes by finely adjusting the interelectrode distance.
From this characteristic, the Raman peak intensity ratio is evaluated by the film quality monitors 7A and 7B, and based on the result, the film quality evaluation calculation unit 8 calculates the relationship between the Raman peak intensity ratio and the interelectrode distance, and the electrode interval command control unit 9 The amount of adjustment of the distance between the electrodes is obtained in comparison with the current amount of the distance between the electrodes, the amount is given as an electrode interval command, and the position of the high-frequency electrode 3B is finely adjusted by moving the electrode (front-rear) moving mechanism 6 The intensity can be controlled within a range within the control value.

Control example, Raman peak intensity a formed under the inter-electrode distance t _a, obtains a Raman peak intensity b formed under the inter-electrode distance t _b, the distance between the electrodes to the Raman peak intensity to be controlled at between And the amount of movement between the current position and the target position of the high-frequency electrode 3B is given to the position control unit of the electrode (front-rear) moving mechanism 6 to move the high-frequency electrode 3B to the target position.
This thin film evaluation is repeated several times to increase the accuracy of the target value.

In addition, since the Raman peak intensity ratio varies depending on the amount of reaction gas, film forming pressure, and film forming temperature, the evaluation result can be fed back to these conditions and controlled.
The thin film monitor measures the length of the film wound around the rollers 1A and 2A, for example, at the part where the film is formed at the beginning of winding of 2200m and the end of winding about 10 to 20m.
The solar cell has a different film type for each stack, and the thin film manufacturing apparatus of this embodiment needs to pre-deposit the film type desired in the film formation chamber 3 to adjust the film formation conditions. Perform this pre-depot about 20m.
By evaluating the thin film in this pre-deposition portion, film formation preparation and thin film evaluation can be performed simultaneously.
By using such an evaluation method, the evaluation result of the microcrystalline silicon film can be fed back to the film formation conditions for each stack, and the production efficiency of the solar cell is improved.

FIG. 3 is a conceptual diagram showing a thin film manufacturing apparatus according to another embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description of the same parts is omitted.
Between the roll substrate storage chamber 1 and the film formation chamber 3 of the film formation chamber 3 (thin film forming means) disposed between the roll substrate storage chambers 1 and 2 that respectively store one end side and the other end side of the belt-like substrate S. Gate valves 31 and 32 are respectively installed in the substrate passages 30a and 30b of the partition wall 30 that partition the space between the film formation chamber 3 and the roll substrate storage chamber 2, thereby exposing the film formation chamber 3 to the atmosphere. However, the vacuum state of the roll substrate storage chambers 1 and 2 is maintained.
For this reason, the film-forming chamber 3 can be returned to the atmosphere while maintaining the vacuum in the film-forming substrate S in the roll substrate storage chambers 1 and 2, and the electrode can be maintained. Without electrode maintenance, the roll substrate can only be formed to a length of several hundreds of meters, and the shortening of substrate replacement, which is an advantage of roll substrate deposition, cannot be made use of. A film with a substrate length of 2200 m can be formed. In addition, the number of electrodes can be reduced, and the footprint can be reduced.

1 Roll substrate storage chamber (first substrate storage means)
2 Roll substrate storage chamber (second substrate storage means)
3 Deposition chamber (Thin film forming means)
3A Common installation electrode 3B High frequency electrode 4A Detection roller 4B Auxiliary roller 5A Detection roller 5B Auxiliary roller 6 Electrode (front-rear) moving mechanism 7A, 7B Monitor (detection unit)
8 Film quality evaluation calculation unit 9 Electrode interval command control unit 30 Partition wall 30a, 30b Substrate passage 31, 32 Gate valve

Claims (6)

  Between the first substrate storage means for storing one end side of the band-shaped substrate and the second substrate storage means for storing the other end side of the band-shaped substrate, the first substrate storage means and the second substrate Each time a single layer of the thin film is formed, a thin film forming means for selectively forming one of a plurality of types of thin films is disposed on the main surface of the substrate while feeding the substrate from one of the storage means toward the other. In the thin film manufacturing method in which the plurality of types of thin films are sequentially stacked on the main surface by reversing the feeding direction of the substrate and changing the type of thin film, a detection unit for detecting the thin film formed on the belt-shaped substrate is the substrate. Provided in the storage means, provided with a film quality evaluation calculation unit for evaluating the film quality of the thin film detected by the detection unit, and calculating an appropriate electrode interval, and determining the electrode interval from the calculation result of the film quality evaluation calculation unit Controlled by Thin film manufacturing method comprising.   2. The thin film manufacturing method according to claim 1, wherein a thin film is formed by controlling a film forming gas amount and / or input power in a film forming chamber of the thin film forming means from a calculation result of the film quality evaluation calculating unit. .   The chamber between the film forming chamber constituting the thin film forming means and the storage chamber constituting the first and second substrate storage means is partitioned by a partition valve, and is unwound from the storage chamber or wound into the storage chamber. The thin film manufacturing method according to claim 1 or 2, wherein the atmospheric pressure in the first and second storage chambers is maintained in a vacuum by allowing the substrate to pass through in close contact with a gate valve. First substrate storage means for storing one end side of the belt-shaped substrate;
Second substrate storage means for storing the other end side of the belt-shaped substrate;
Between the first substrate storage means and the second substrate storage means, a pair of electrodes facing each other are built in and arranged from one of the first substrate storage means and the second substrate storage means. Forming a plasma state by discharging between the electrodes while sending the substrate toward the other, and comprising a thin film forming means for selectively forming any of a plurality of types of thin films on the main surface of the substrate,
In the thin film manufacturing apparatus in which the plurality of types of thin films are sequentially formed on the main surface by reversing the feeding direction of the substrate every time one layer of the thin film is formed and changing the type of thin film,
Each of the first substrate storage means and the second substrate storage means is provided with a detection unit for detecting a thin film, and a conveyance path for guiding the belt-like substrate is provided so as to be close to the detection unit at a fixed interval. A detection roller that changes the conveyance direction is arranged between a pair of rollers arranged in the path, and a film quality evaluation calculation unit that calculates an appropriate electrode interval is provided while evaluating a film quality based on a signal from the detection unit. An apparatus for manufacturing a thin film, comprising: an electrode interval command control unit that controls the electrode interval based on a signal from a film quality evaluation calculation unit.   The thin film manufacturing apparatus according to claim 4, further comprising an electrode moving mechanism that adjusts a distance between the electrodes.   A partition valve is provided on a partition wall that partitions between the film forming chamber constituting the thin film forming means and the storage chambers constituting the first and second substrate storage means, and is unwound from the storage chamber or stored. The thin film manufacturing apparatus according to claim 4 or 5, wherein a partition valve is brought into close contact with a substrate wound around the chamber to maintain the pressure in the storage chamber.

Images