JP2865971B2 - Thin film manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for transporting a flexible film substrate by winding it around a heating drum rotating in a vacuum.
The present invention relates to a thin film manufacturing apparatus for continuously depositing a thin film on a flexible film substrate.

[0002]

2. Description of the Related Art A thin film manufacturing apparatus for continuously depositing a thin film on a flexible film substrate while wrapping and transporting the flexible film substrate around a heating drum rotating in a vacuum is known as a thin film manufacturing apparatus. It is already widely used in industry in sputtering equipment and the like.

[0003] Such conventional sputtering apparatuses include:
A heating drum for heating the flexible film substrate is provided. And from the unwinding of the substrate film, the deposition of the thin film,
In the process up to the winding of the film, the back surface of the film comes into contact with the rotating heating drum, but the film surface on which the thin film is deposited does not come into contact with other rollers or the like.

More recently, a thin film deposited on a film substrate is not a single-layer film but a multilayer film, and the number of deposition regions is increasing. As a result, using multiple heating drums,
A structure in which the film travels between them is adopted.

In such a case, in order to control the running direction of the film in the limited space, a touch roll for controlling the transport direction of the flexible film substrate drawn from the heating drum is provided. It is provided so as to come into contact with the coating surface of the film drawn from the drum.

[0006]

In such a thin film manufacturing apparatus, very small scratches often occur on the coating surface, and a thin film, such as an amorphous silicon solar cell, which exhibits an electrical function in a bonding structure of a multilayer film. In a battery or the like, there is a problem that a short circuit phenomenon occurs and a film having a sufficient function cannot be formed.

An object of the present invention is to solve the above problems and to obtain a thin film manufacturing apparatus in which the surface of a deposited film has no scratch.

[0008]

The thin film manufacturing apparatus of the present invention includes a heating drum for heating a flexible film substrate, and a touch roll for controlling a direction of transport of the flexible film substrate drawn from the heating drum. In a thin film manufacturing apparatus for continuously depositing a thin film on a flexible film substrate while winding and transporting the flexible film substrate around a heating drum rotating in a reaction chamber where the thin film is deposited, the degree of vacuum in the reaction chamber is reduced. Is controlled to 1.33 kPa or less, and the surface temperature Tt (° C.) of the touch roll immediately after the heating drum is controlled with respect to the surface temperature Td (° C.) of the heating drum within a range of Td−100 <Tt <Td. It is characterized by:

That is, as a result of earnest study by the present inventors,
It became clear that fine scratches on the coating surface were generated as follows.

First, even if the flexible film substrate heated by the heating drum and deposited on the thin film loses contact with the heating drum, the surroundings are in a vacuum so that heat is released little and it is not cooled rapidly. In particular, in a vacuum at a pressure of 1.33 kPa or less, which is suitable for plasma CVD, sputtering, and the like, the thermal conductivity due to the residual gas is rapidly reduced as compared with that at normal pressure, so that the influence is large.

On the other hand, the temperature of a conventional touch roll without temperature control is close to room temperature. For this reason, the flexible film substrate is rapidly cooled when it separates from the heating drum and comes into contact with the touch roll. At that time, the flexible film substrate contracts on the touch roll, and abrasion occurs in the width direction of the film by the surface of the touch roll. The degree of the generation of the flaw is affected by the difference between the heating temperature of the heating drum and the temperature of the touch roll, the distance between the drum and the roll, the transport speed of the film, and the degree of vacuum.

Here, it is preferable that the thin film manufacturing apparatus is designed as compact as possible in terms of cost and maintenance of vacuum, and it is not preferable to increase the distance between the heating drum and the touch roll. Further, it is not preferable to set the degree of vacuum higher than 1.33 kPa, which is a pressure range suitable for plasma CVD, sputtering, or the like. Alternatively, reducing the transport speed of the film substrate is not preferable in terms of productivity.

Therefore, as means for solving the problems in the present invention, it is necessary to control the surface temperature of the touch roll so that the flexible film substrate is not rapidly cooled. At this time, the surface temperature of the touch roll is selected depending on the surface hardness of the film deposited on the film substrate surface, the slipperiness with the touch roll, and the like.
In contrast to (° C.), it is necessary to control the surface temperature Tt (° C.) of the touch roll immediately after the heating drum in a range of Td−100 <Tt <Td.

Further, the generation of the flaw, which is a problem, is affected by the amount of deformation of the flexible film substrate on the surface of the heating drum or the surface of the touch roll, that is, the amount of thermal expansion. Therefore, when forming a thin film on a flexible film substrate having a linear expansion coefficient of 0.00001 / ° C. or more, it is more preferable to use the thin film manufacturing apparatus according to the present invention.

Alternatively, when forming an amorphous silicon thin film exhibiting an electrical function by a bonding structure of a multi-layer film by a plasma CVD method, the use of the thin film manufacturing apparatus according to the present invention makes it possible to produce very small scratches on the film surface. This is more preferable because a short circuit phenomenon due to the above can be prevented.

As a method for heating the touch roll, a method such as a heater embedded type, a heating medium circulation type, and a lamp heating type can be used.

[0017]

FIG. 1 shows an apparatus for manufacturing a thin film according to an embodiment of the present invention. That is, this is a schematic configuration of a three-chamber roll-to-roll plasma CVD apparatus for forming an amorphous silicon thin film solar cell on a flexible film substrate.

In the figure, 10 is a film unwinding chamber, 20 is an n-layer reaction chamber for depositing an n-layer of a solar cell, 30 is an i-layer reaction chamber for depositing an i-layer of a solar cell, and 40 is a p-layer of a solar cell. Is a p-layer reaction chamber for depositing, and 50 is a film winding chamber. 11 is a film unwinding roll, and 51 is a film unwinding roll. 21, 31 and 41 are heating drums in each reaction chamber. Further, 12, 22, 32, 42, and 52 are touch rolls that do not perform temperature control. Meanwhile, 23, 3
3, and 43 are touch rolls that perform temperature control,
A heater for that purpose is embedded inside. Also 2
Reference numerals 4, 34, and 44 are electrodes for plasma CVD.
Reference numeral 60 denotes a long flexible film substrate. The distance between each heating drum and the touch roll is 5 cm. The room temperature at which this device was installed was 30 ° C.

The flexible film substrate 60 has a thickness of 75 μm.
m of polyethylene naphthalate film (linear expansion coefficient =
A substrate for a flexible solar cell, in which an Al / stainless thin film was deposited to a thickness of 0.4 μm / 4 nm as a lower electrode by a sputtering method on a surface of 0.000013 / ° C.).

The flexible film substrate 60 is mounted on an unwinding roll 11, and each of the reaction chambers 20 for n-layer, i-layer and p-layer,
It is wound up on a winding roll 51 via 30, 40. Here, the transport speed of the flexible film substrate 60 is 3 cm
/ Min.

In each reaction chamber, a thin film is deposited while the flexible film substrate 60 is conveyed while being in contact with each heating drum. Therefore, the reaction pressure in each reaction chamber and the RF discharge power during deposition of the thin film were set to 266 Pa and 200 W in the n-layer reaction chamber 20 and the p-layer reaction chamber 40, and 133 Pa and 40 W in the i-layer reaction chamber 30. In this embodiment, the n-layer / i-layer / p-layer are respectively
Deposited to a thickness of 50 nm / 550 nm / 8 nm.

At this time, the surface temperature of the heating drums 21 and 41 is
The temperature of the heating drum 31 is controlled at 200 ° C., and the temperature of the heating drum 31 is controlled at 200 ° C. On the other hand, the temperatures of the touch rolls 22, 32 and 42 are almost the same as the room temperature of 30 ° C. On the other hand, the surface temperature of the touch rolls 23 and 43 is controlled to 100 ° C. As examples and comparative examples of the present invention, the surface temperature of the touch roll 33 is 160 ° C. (Example 1), 120 ° C. (Example 2), 80 ° C. (Comparative Example 1), 40 ° C. (Comparative Example 2), There was no temperature control (Comparative Example 3).

The amorphous silicon film thus manufactured is
Observation was performed with a microscope of 0 magnification, and the number of scratches generated in a square of 2 cm was counted. Furthermore, an ITO film having a thickness of 60 was formed on the amorphous silicon film as a transparent electrode by another electron beam evaporation apparatus.
nm to form a solar cell. The output of the solar cell was measured under an illumination of 200 lx fluorescent light.

As a result of the measurement, a difference was observed in the output of the solar cell due to the influence of the leak current generated by the short circuit due to the scratch.
That is, in Example 1, the number of scratches was 0 and the solar cell output was
3.0 μW / cm 2. In Example 2, the number of scratches was 1 and the solar cell output was 3.0 μW / cm 2. In Comparative Example 1, the number of scratches was 8, and the solar cell output was 1.8 μW / cm 2. In Comparative Example 2, the number of scratches was 12, and the solar cell output was 1.0 μW / cm 2. In Comparative Example 3, the number of scratches was 12 and the solar cell output was 0.
8 μW / square cm. As is clear from these results, when the surface temperature of the touch roll 33 is 120 ° C. or higher, scarring is hardly observed, and the solar cell performance does not decrease.

[0025]

As described above in detail, according to the present invention, it is possible to obtain an apparatus for producing a thin film having no flaws on the surface of the deposited film.

[Brief description of the drawings]

FIG. 1 is a schematic configuration of a three-chamber separation roll-to-roll plasma CVD apparatus.

[Explanation of symbols]

 10 Film unwinding chamber 11 Film unwinding roll 12 Touch roll without temperature control 20 n-layer reaction chamber for depositing n-layer of solar cell 21 Heating drum 22 Touch roll without temperature control 23 Touch roll with temperature control 24 Electrode for plasma CVD 30 i-layer reaction chamber for depositing i-layer of solar cell 31 heating drum 32 touch roll without temperature control 33 touch roll for temperature control 34 electrode for plasma CVD 40 deposit p-layer of solar cell P-layer reaction chamber 41 heating drum 42 touch roll without temperature control 43 touch roll with temperature control 44 electrode for plasma CVD 50 film winding chamber 51 film winding roll 52 touch roll without temperature control 60 flexible Film substrate

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C23C 14/56 C23C 14/54 C23C 16/54

Claims (3)

(57) [Claims] A heating drum for heating a flexible film substrate; a touch drum for controlling a transport direction of the flexible film substrate drawn from the heating drum; and a heating drum rotating in a reaction chamber for depositing a thin film. In a thin film production apparatus for continuously depositing a thin film on a flexible film substrate while winding and transporting the flexible film substrate over the flexible film substrate, the degree of vacuum in the reaction chamber is reduced to 1.33 kPa or less, and the heating drum For the surface temperature Td (° C.), the surface temperature Tt (° C.) of the touch roll immediately after the heating drum is represented by Td-100 <Tt <.
An apparatus for manufacturing a thin film, wherein the temperature is controlled within a range of Td. 2. A flexible film substrate having a linear expansion coefficient of 0.00
2. The thin film manufacturing apparatus according to claim 1, wherein the temperature is 001 / ° C. or higher. 3. A plasma CV on a flexible film substrate.
3. A thin film manufacturing apparatus according to claim 1, wherein an amorphous silicon thin film is deposited by a method D.