JP6376685B2 - Thin film forming apparatus and thin film forming method - Google Patents

Description

  The present invention is a thin film forming apparatus for forming a thin film on a band-shaped substrate, and forms a thin film on the band-shaped substrate with high purity by passing the film-shaped chamber while conveying the band-shaped substrate. The present invention relates to a thin film forming apparatus.

  In recent years, a film with a barrier in which a barrier film is formed on the surface of a plastic film for the purpose of, for example, preventing oxidation or preventing water intrusion has been used.

  Such a film with a barrier is formed by a thin film forming apparatus shown in Patent Document 1 below. For example, as shown in FIG. 4, the thin film forming apparatus includes a main roll chamber 101, a main roll 102 accommodated in the main roll chamber 101, a transport roll 104 for feeding the strip-shaped substrate 103, and the strip-shaped substrate 103. The belt-like base material 103 is transported along the outer peripheral surface 102a of the main roll 102 by the carrier roll 105 along the outer peripheral surface 102a of the main roll 102. It is like that. Then, by providing the partition 106 on the outer diameter side of the main roll 102, the film forming chamber 107 and the film forming chamber 108 are formed in the circumferential direction of the main roll 102. Are provided with electrodes, and a thin film source gas is supplied to the film forming chamber 107 and the film forming chamber 108, and a high frequency voltage is applied to each electrode, whereby the source gas becomes a plasma state. A thin film is formed on the substrate 103.

  In such a thin film forming apparatus, the belt-like substrate 103 supplied from the transport roll 104 passes through the film-forming chamber 107 and the film-forming chamber 108 in a state along the outer peripheral surface 102 a of the main roll 102, thereby forming the belt-like substrate. A predetermined thin film is sequentially laminated on the material 103.

  In addition, after the belt-like substrate 103 is conveyed by a predetermined length, the rotation direction of the conveyance roll 104 and the conveyance roll 105 is reversed, so that the conveyance roll 105 unwinds and conveys the belt-like substrate 103 in the opposite manner. The roll 104 is wound up around the belt-like base material 103, and the belt-like base material 103 is conveyed in the opposite direction. Then, film formation is performed in the film forming chamber 107 by performing film formation in the film forming chamber 107 and the film forming chamber 108 while transporting the belt-like substrate 103 so as to reciprocate between the transport roll 104 and the transport roll 105. Thin films and thin films formed by the film formation chamber 108 can be alternately stacked on the strip-shaped substrate 103.

JP 2001-303249 A

  However, in the above thin film forming apparatus, the film quality of the formed thin film may be deteriorated. Specifically, when reversing the conveyance direction of the belt-like substrate 103, the conveyance speed of the belt-like substrate 103 is decelerated from a predetermined speed, and once the conveyance speed is zero, the conveyance speed in the opposite direction is predetermined. Need to accelerate to speed. Meanwhile, since the conveyance speed of the belt-like substrate 103 is slower than the predetermined speed, the time during which the belt-like substrate 103 is exposed to plasma per unit area becomes longer, and the belt-like substrate 103 is heated by the heat given by the plasma. It was growing hot. As a result, wrinkles extending in the conveying direction (long direction of the band-shaped substrate 103) occurred in the band-shaped substrate 103, and such wrinkles had an adverse effect such as a deterioration in film thickness distribution during film formation. In addition, once this wrinkle occurs, there is a possibility that it extends over the entire length of the belt-like base material 103, and there has been a case where most of the belt-like base material 103 has to be discarded.

  On the other hand, in order not to cause thermal elongation in the belt-like substrate 103, means for stopping the plasma discharge by stopping the application of the high-frequency voltage while the conveyance speed is slow is used. However, after the plasma discharge is stopped once, it takes a long time of about one minute until the discharge is stabilized after the discharge is started again. The thin film formed by the plasma in an unstable state until the discharge becomes stable has poor film quality and film thickness distribution. Therefore, the belt-like substrate 103 that has passed through the film formation chamber 107 and the film formation chamber 108 until the discharge becomes stable. This part had to be discarded, resulting in great waste.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a thin film forming apparatus and a thin film forming method capable of obtaining a substrate on which thin films are laminated with high yield.

  In order to solve the above problems, a thin film forming apparatus of the present invention includes a pair of transport rolls for reciprocally transporting a belt-like substrate, one of which feeds the belt-like substrate and the other of which takes up the belt-like substrate, and a belt-like substrate. A film forming chamber for enclosing a part of the film forming surface and forming a closed space with the part of the film forming surface, a source gas supplying means for supplying source gas to the closed space, and a high frequency power source And a plasma electrode that converts the source gas in the closed space into plasma, and a thin film containing the source gas as a component by applying the source gas converted into plasma in the film formation chamber to the film formation surface. A thin film forming apparatus for forming, having a film forming mode for forming a thin film on a belt-like substrate while conveying the belt-like substrate at a predetermined speed, and a reversing mode for reversing the conveyance direction of the belt-like substrate. The above-mentioned unit area of the substrate The amount of heat Zuma is in unit time, when the reverse mode is characterized by further comprising a heat transfer limiting means for lower than during the deposition mode.

  According to the thin film forming apparatus, it is possible to obtain a base material on which a thin film is laminated with a high yield without causing the belt-like base material to thermally stretch. Specifically, by further comprising a heat transfer limiting means for lowering the amount of heat given by the plasma per unit time to the unit area of the belt-shaped substrate in the inversion mode than in the film formation mode, the inversion is performed. Even when the conveyance speed of the belt-like base material is slow during the mode, the heat-elongation of the belt-like base material can be prevented. Moreover, since the plasma is continuously generated, a thin film can be formed with plasma in a stable state immediately after the conveyance speed of the belt-shaped substrate reaches a predetermined speed. Of these, parts that need to be discarded can be minimized.

  Further, the heat transfer limiting means may be a plasma intensity control means for lowering the plasma intensity in the inversion mode to be lower than the plasma intensity in the film forming mode.

  According to this structure, even if the state where the plasma touches the belt-like base material is maintained, the thermal elongation of the belt-like base material can be prevented.

  The plasma intensity control means may be configured such that the voltage applied to the plasma electrode in the inversion mode is a standby voltage that is lower than the film formation voltage that is the voltage in the film formation mode. good.

  According to this configuration, the plasma intensity can be easily controlled.

  The heat transfer limiting means is a shutter device that shields between the film formation surface and the plasma electrode, and the shutter device has a shielding position that shields between the film formation surface and the plasma electrode. The plasma electrode and the film forming surface may be movable between a standby position that does not hinder the movement of the plasma.

  According to this configuration, it is possible to form a state in which the plasma does not touch the band-shaped substrate, and it is possible to reliably prevent the band-shaped substrate from being thermally stretched in the inversion mode.

  Further, in order to solve the above-mentioned problems, the thin film forming method of the present invention is a thin film containing the raw material gas as a component by applying a plasma source gas to the film forming surface of the belt-like substrate while reciprocating the belt-like substrate. A film forming method for forming the thin film on the belt-like substrate while conveying the belt-like substrate at a predetermined speed, and a reversing step for reversing the conveyance direction of the belt-like substrate, The amount of heat given by the plasma per unit time to the unit area of the belt-like substrate is lower in the inversion step than in the film formation step.

  According to the above thin film forming method, a base material on which a thin film is laminated can be obtained with a high yield without causing the belt-like base material to thermally stretch. Specifically, the amount of heat given by the plasma per unit time to the unit area of the belt-shaped substrate is lower than that during the film-forming step during the reversing step, so that the conveyance speed of the belt-shaped substrate during the reversing step. Even when the film becomes slow, it is possible to prevent thermal expansion of the band-shaped substrate. Moreover, since the plasma is continuously generated, a thin film can be formed with plasma in a stable state immediately after the conveyance speed of the belt-shaped substrate reaches a predetermined speed. Of these, parts that need to be discarded can be minimized.

  According to the thin film forming apparatus and the thin film forming method of the present invention, a substrate on which thin films are laminated can be obtained with a high yield.

It is the schematic which shows the thin film formation apparatus in one Embodiment of this invention, and is a perspective view. It is the schematic which shows the thin film formation apparatus in one Embodiment of this invention, and is a front view. It is the schematic which shows the thin film formation apparatus in other embodiment of this invention. It is the schematic which shows the conventional thin film forming apparatus.

  Embodiments according to the present invention will be described with reference to the drawings.

  1 and 2 are schematic views of a thin film forming apparatus 1 according to an embodiment of the present invention.

  The thin film forming apparatus 1 is for forming a thin film by performing a surface treatment on a base material. For example, a thin film forming apparatus 1 is used for forming a barrier film on a plastic film for the purpose of preventing oxidation and preventing moisture intrusion, Used for protective films, sealing films for flexible solar cells, and the like. Specifically, in the case of a sealing film for a flexible solar battery, a thin film forming apparatus 1 is formed after a solar battery cell composed of each electrode layer, a photoelectric conversion layer, and the like is formed on a belt-like substrate such as a plastic film. Thus, a plurality of thin films are formed on the solar battery cell to form a barrier film. Thereby, the penetration | invasion of a water | moisture content into a photovoltaic cell is prevented effectively, and the flexible solar cell excellent in the oxidation characteristic can be formed.

  The thin film forming apparatus 1 includes a transport roll 3 that feeds the strip-shaped substrate 2, a transport roll 4 that winds the supplied strip-shaped substrate 2, and a main roll 5 that is disposed between the transport roll 3 and the transport roll 4. And a main roll chamber 6 for accommodating these and a film forming chamber 7 for forming a thin film, and the belt-like substrate 2 fed from the transport roll 3 is placed along the outer peripheral surface 51 of the main roll 5. A thin film is formed on the belt-like substrate 2 by passing through each film forming chamber 7 while being transported, and is wound up by the transport roll 4.

  The transport roll 3 and the transport roll 4 have a substantially cylindrical core portion 31 and a core portion 41, and the belt-like substrate 2 is wound around the core portion 31 and the core portion 41. By rotating 41, the belt-like substrate 2 can be sent out or taken up. That is, by controlling the rotation of the core portion 31 and the core portion 41 by a control device (not shown), it is possible to increase and decrease the feeding speed or the winding speed of the belt-like substrate 2. Specifically, the belt-like base material 2 is sent to the downstream side by rotating the upstream core portion in a state where the belt-like base material 2 receives a tensile force from the downstream side. By applying the brake, the belt-like substrate 2 is fed out at a constant speed without being bent. In addition, by adjusting the rotation of the downstream core, the belt-like base material 2 that has been fed out is restrained from being bent, and conversely, the belt-like base material 2 is wound so as not to be applied with an unnecessary tension. Can be done.

  Here, the strip | belt-shaped base material 2 is a thin plate-shaped elongate body extended in one direction, and the elongate body which has a flat plate shape of thickness 0.01mm-0.2mm width 5mm-1000mm is applied. Moreover, although it does not specifically limit as a material, In addition to metal materials, such as stainless steel and copper, a plastic film etc. are used suitably.

  In this manner, the transport roll 3 and the transport roll 4 are paired, one of which feeds the strip-shaped base material 2 and the other of which winds the strip-shaped base material 2 at the same winding speed as the feed-out speed. It is possible to transport the belt-like substrate 2 while maintaining the tension applied to the material 2 at a predetermined value. In addition, although the conveyance roll 3 sends out the strip | belt-shaped base material 2 and shows the form which the conveyance roll 4 winds up the strip | belt-shaped base material 2 by the above, by reversing the rotation direction of the conveyance roll 3 and the conveyance roll 4, the said Contrary to this, the transport roll 4 feeds the strip-shaped substrate 2 and the transport roll 3 winds the strip-shaped substrate 2, and the transport direction of the strip-shaped substrate 2 is reversed.

  The main roll 5 is for conveying the belt-like substrate 2 supplied from the upstream-side conveyance roll to the downstream-side conveyance roll while maintaining the posture of the belt-like substrate 2 during film formation. The main roll 5 is disposed between the transport roll 3 and the transport roll 4 and is formed in a substantially cylindrical shape having a larger diameter than the core portion 31 and the core portion 41. The outer peripheral surface 51 of the main roll 5 is formed with a curved surface having a constant curvature in the circumferential direction, and is driven and controlled according to the rotation of the core portion 31 and the core portion 41 by a control device (not shown). Further, the main roll 5 is provided at a position where the outer peripheral surface 51 protrudes downward as compared with the core portion 31 and the core portion 41, and the belt-like substrate 2 is bridged over the protruding outer peripheral surface 51. ing. That is, the belt-like base material 2 fed out from the upstream transport roll is transported in a state where a predetermined tension is applied by contacting the outer peripheral surface 51 of the main roll 5. That is, when the main roll 5 rotates according to the rotation of the transport roll 3 and the transport roll 4 with the strip-shaped base 2 in contact with the outer peripheral surface 51 of the main roll 5, the strip-shaped base 2 is In a state where the whole is stretched, the surface thereof is conveyed from the upstream conveyance roll to the downstream conveyance roll in a posture facing each film forming chamber 7.

  The main roll chamber 6 is for accommodating the main roll 5 and keeping the pressure in the chamber constant. In the present embodiment, as shown in FIG. 1, the main roll chamber 6 is a casing formed in a substantially home-base-shaped pentagon, and the main roll 5 is accommodated in the central portion thereof. A vacuum pump 61 is connected to the main roll chamber 6. By operating the vacuum pump 61, the pressure in the main roll chamber 6 can be controlled. In the present embodiment, the pressure is set to be lower than that of each film forming chamber 7. In this embodiment, the transport roll 3 and the transport roll 4 are accommodated in the main roll chamber 6, but a configuration in which these are provided outside the main roll chamber 6 may be employed. By providing these in the main roll chamber 6 as in the present embodiment, it is possible to protect the belt-like substrate 2 and the belt-like substrate 2 (film-forming substrate) after film formation from being exposed to the atmosphere.

  The film forming chamber 7 is for forming a thin film on the belt-like substrate 2. In the present embodiment, two film forming chambers 7 having the same structure are provided. These film forming chambers 7 are provided in the main roll chamber 6, and in this description, the one near the transport roll 3 is the first film forming chamber 7a, and the one near the transport roll 4 is the second film forming chamber 7b. Call. Here, when the first film forming chamber 7a and the second film forming chamber 7b are not distinguished from each other, they are simply referred to as the film forming chamber 7. The first film forming chamber 7 a and the second film forming chamber 7 b are formed by disposing a partition 62 on the outer diameter side of the main roll 5. Specifically, on the outer diameter side of the main roll 5, three substantially plate-like partition portions 62 are provided so as to extend toward the outer peripheral surface 51 of the main roll 5, so that the outer periphery of the main roll 5 is A part of the film forming surface (surface opposite to the surface in contact with the main roll) of the belt-like substrate 2 formed on the surface 51, the partition 62 and the wall surface of the main roll chamber 6 on the main roll 5. Two film forming chambers 7 are formed so as to surround and form a closed space between a part of the film forming surface. Thereby, for example, when the belt-like substrate 2 is conveyed from the conveyance roll 3 to the conveyance roll 4 along the main roll 5, the belt-like substrate 2 that has passed through the first partition 62 is transferred to the first film forming chamber 7a. The belt-shaped substrate 2 that has been transported and then passed through the second partition 62 is transported to the second film-forming chamber 7b, whereby the first film-forming chamber 7a and the second film-forming chamber 7b respectively A thin film is sequentially formed on the material 2.

  In addition, in this embodiment, in order to prevent the partition part 62 from interfering with the strip-shaped base material 2 and damaging the strip-shaped base material 2, it is between the strip-shaped base material 2 on the main roll 5 and the end of the partition part 62. Is configured to have a slight gap. Therefore, the space formed between the film forming chamber 7 and the belt-like substrate 2 is not strictly a closed space, but in this description, even a space having a slight gap is called a closed space. I will do it.

  These film forming chambers 7 are connected to vacuum pumps 71a and 71b. By operating the vacuum pumps 71a and 71b, the film forming chamber 7a and the film forming chamber 7b can be set to a predetermined pressure. It has become. In the present embodiment, the inside of the film forming chamber 7 is depressurized until a predetermined pressure is reached before supplying the source gas.

  Further, these film forming chambers 7 are provided with a film forming source using a plasma CVD method as a surface treatment for the belt-like substrate 2. That is, the film forming chamber 7 is provided with a substantially U-shaped plasma electrode 72 that is connected to a high frequency power source 74 and generates plasma in a closed space in the film forming chamber 7, and is a source gas supply means. A source gas pipe 73 is connected. Specifically, the first film formation chamber 7a is provided with a plasma electrode 72a connected to a high frequency power supply 74a, and the second film formation chamber 7b is provided with a plasma electrode 72b connected to a high frequency power supply 74b. ing. A source gas pipe 73a is connected to the first film forming chamber 7a, and a source gas pipe 73b is connected to the second film forming chamber 7b. As a result, a predetermined thin film is formed on the belt-like substrate 2 passing through the first film forming chamber 7a and the second film forming chamber 7b. That is, when a source gas is supplied into the film forming chamber 7, a high frequency voltage is applied to the plasma electrode 72 by the high frequency power source 74, whereby plasma is generated around the plasma electrode 72, and the source gas is generated by this plasma. Is excited, and the inside of the film forming chamber 7 becomes a plasma atmosphere, and a predetermined thin film is formed on the belt-like substrate 2. In the present embodiment, in the first film forming chamber 7a, an HMDS (hexamethyldisilazane) gas, an argon gas, and a hydrogen gas are supplied as source gases, thereby forming a highly adhesive Si compound film (first thin film). In the second film formation chamber 7b, a dense SiO2 film (second thin film) having high barrier properties is formed by supplying HMDS and oxygen gas as source gases. The vacuum pumps 71a and 71b, the plasma electrodes 72a and 72b, the source gas pipes 73a and 73b, and the high frequency power sources 74a and 74b are simply referred to as the vacuum pump 71, the plasma electrode 72, the source gas pipe 73, It will be referred to as a high frequency power source 74.

  Further, plasma intensity control means 75 (plasma intensity control means 75a and plasma intensity control means 75b) is provided in the middle of the wiring connecting the high-frequency power source 74 and the plasma electrode 72. In the present embodiment, the voltage control device controls the voltage applied to the plasma electrode 72, and has a role of heat transfer limiting means described later.

  When the strip-shaped substrate 2 is first transported from the transport roll 3 to the transport roll 4 by the thin film forming apparatus 1 having the above-described configuration, the strip-shaped substrate 2 first passes through the first film formation chamber 7a. A thin film is formed. Then, the belt-like substrate 2 on which the first thin film is formed continues to pass through the second film forming chamber 7b, and the second thin film is formed on the first thin film. Thus, as a result of continuing conveyance from the conveyance roll 3 to the conveyance roll 4, most of the strip | belt-shaped base materials 2 wound around the conveyance roll 3 core part 31 move to the core part 41 of the conveyance roll 4, and a strip | belt-shaped base material After the first thin film and the second thin film are laminated on almost the entire surface of 2, when the rotation direction of the core portion 31 and the core portion 41 is reversed, the transport direction of the belt-like substrate 2 is reversed and the belt-like substrate 2 is again In order to pass through the film forming chamber 7b and the film forming chamber 7a, a first thin film is further laminated on the second thin film. Thereafter, the second thin film is further formed on the first thin film by further reversing the transport direction of the belt-shaped substrate 2, and the thin film is formed in the two film forming chambers 7 while reversing the transport direction of the strip-shaped substrate 2. By forming it, two kinds of thin films can be alternately laminated. Thereby, the sealing film which has both high barrier property and adhesiveness can be formed in the strip | belt-shaped base material 2. FIG.

  Further, by keeping the conveyance speed of the strip-shaped substrate 2 during the formation of the thin film constant, a thin film having a uniform film thickness can be formed over the entire length of the strip-shaped substrate 2, and the sealing film has no unevenness in barrier properties. Can be obtained. In addition, in this description, this constant conveyance speed at the time of thin film formation is called a film formation conveyance speed. In addition, in this description, the thin film forming apparatus 1 performs an operation of forming a thin film while transporting the belt-shaped substrate 2 at the film deposition transport speed, which is referred to as a film deposition mode.

  On the other hand, when the transport direction of the belt-shaped substrate 2 is reversed and the belt-shaped substrate 2 is transported in the opposite direction at the film deposition transport speed, the transport speed of the belt-shaped substrate 2 is once decelerated from the film deposition transport speed, After the conveyance speed becomes zero, it is necessary to accelerate the conveyance speed of the strip-shaped substrate 2 until the conveyance speed in the opposite direction becomes the film formation conveyance speed. The thin film forming apparatus 1 performing such an operation is referred to as a reversal mode in the present description. In this reversal mode, the transport speed of the belt-shaped substrate 2 is the transport speed when the film formation mode is set (deposition transport speed). Therefore, the time during which the belt-shaped substrate 2 is exposed to the plasma atmosphere is longer than that in the film forming mode.

  When forming a thin film on the film-forming surface of the strip-shaped substrate 2, not only the source gas excited by the plasma touches the strip-shaped substrate 2, but also the plasma touches the strip-shaped substrate 2, thereby depending on the intensity of the plasma. The amount of heat is given to the belt-like substrate 2. When the amount of heat given to the unit area of the strip-shaped substrate 2 exceeds a predetermined value, the strip-shaped substrate 2 undergoes deformation such as thermal elongation. When the belt-like substrate 2 is deformed in this way, wrinkles (vertical wrinkles) are generated in the belt-like substrate 2 on the main roll 5, and it becomes difficult to stack thin films with a uniform film thickness. Further, as described above, since the time during which the strip-shaped substrate 2 is exposed to the plasma in the inversion mode becomes longer, the plasma having the same intensity as that in the film formation mode is applied to the strip-shaped substrate 2 in the inversion mode. When applied, the amount of heat given to the unit area of the strip-shaped substrate 2 may exceed a predetermined value, and the strip-shaped substrate 2 may be deformed.

  Here, in the present invention, the amount of heat that the plasma gives to the unit area of the belt-like substrate 2 per unit time by the heat transfer limiting means is made lower in the inversion mode than in the film formation mode. Specifically, in this embodiment, the plasma intensity control means 75 is used as a heat transfer limiting means, and the voltage applied to the plasma electrode 72 in the inversion mode is set to be higher than the film formation voltage that is the voltage in the film formation mode. By controlling the plasma intensity control means 75 to a standby voltage that is a low voltage, the plasma intensity in the inversion mode is made lower than the plasma intensity in the film forming mode.

  Thereby, even if it is a case where the conveyance speed of the strip | belt-shaped base material 2 becomes slow in the reversal mode, the heat amount transmitted from the plasma to the unit area of the strip-shaped base material 2 can be made smaller than in the film-forming mode. For this reason, it is possible to prevent the belt-like substrate 2 from being deformed during the reverse mode.

  Here, in the present invention, the plasma is not extinguished in the inversion mode, but the amount of heat that the plasma gives to the unit area of the strip-shaped substrate 2 per unit time is formed by the heat transfer limiting means while the plasma is generated. Lower than in the mode. This means that if the plasma is generated again after it has been extinguished, a predetermined time is required until the plasma discharge is stabilized so that the fluorescent lamp blinks for a while until the fluorescent lamp is stably turned on. It is necessary.

  The thin film laminated by plasma with unstable discharge causes unevenness in film thickness and film quality, and a predetermined barrier property cannot be obtained. Therefore, there is a thin film laminated by plasma with unstable discharge in the belt-like substrate 2 It is necessary to discard the part to be.

  In the thin film forming apparatus 1 as described herein, it takes about 1 minute for the discharge to stabilize after the plasma is generated. On the other hand, the time required for accelerating the conveyance speed of the belt-like substrate 2 from zero to the film formation conveyance speed in the reverse mode is set to about 20 seconds when the film formation conveyance speed is 5 m / s. Thus, the belt-like substrate 2 can be stably conveyed. Therefore, when the plasma is once extinguished, a portion that cannot be used as a product for a while after the conveyance speed of the belt-like substrate 2 becomes constant occurs.

  On the other hand, by maintaining the generation of the plasma even in the inversion mode as in the present invention, it is possible to return to the plasma intensity in the film formation mode in a short time without causing the plasma discharge to become unstable. Therefore, the film thickness of the thin film can be made constant immediately after the conveyance speed of the belt-like substrate 2 becomes constant at the film formation conveyance speed. That is, for example, when the film forming conveyance speed is 5 m / s, as compared with the case where the plasma is once extinguished, about 3.3 m of the belt-shaped substrate 2 corresponding to the conveyance for 40 seconds is used as a product without waste. It is possible.

  Next, the thin film formation method which forms a thin film on the strip | belt-shaped base material 2 with the thin film formation apparatus 1 mentioned above is demonstrated.

  First, the belt-like base material 2 wound around the core portion 31 of the transport roll 3 is set, and after the belt-like base material 2 is placed along the outer peripheral surface 51 of the main roll 5, it is bridged on the core portion 41 of the transport roll 4. . Then, the vacuum pumps 61 and 71 of the main roll chamber 6 and the film forming chamber 7 are operated to reach a predetermined pressure in each chamber.

  After each chamber reaches a predetermined pressure, a source gas is supplied from a source gas pipe 73 of the film forming chamber 7, and a high frequency voltage is applied to the plasma electrode 72 by a high frequency power source 74. At this time, the pressure in the film forming chamber 7 becomes higher than before the source gas is supplied. At this time, the voltage applied to the plasma electrode 72 is controlled by the plasma intensity control means 75 so as to be the standby voltage. If it is difficult to turn on the plasma with this standby voltage, it is possible to prevent thermal expansion of the belt-shaped equipment 2 by applying a high voltage of about the film formation voltage once and turning it on to instantly set the standby voltage. .

  Next, the conveyance roll 3 and the conveyance roll 4 are driven, and conveyance of the strip | belt-shaped base material 2 is started. The conveyance speed of the belt-like substrate 2 is accelerated from zero and reaches the film formation conveyance speed after a predetermined time, and then the film formation conveyance speed is maintained, but is applied to the plasma electrode 72 immediately before reaching the film formation conveyance speed. The plasma intensity control means 75 is controlled so that the applied voltage becomes the film formation voltage, and when the transport speed of the belt-shaped substrate 2 reaches the film formation transport speed, the voltage applied to the plasma electrode 72 becomes the film formation voltage. Yes.

  On the other hand, after the plasma is turned on, in the first film forming chamber 7a, the source gas excited by being exposed to the plasma atmosphere touches the band-shaped substrate 2, and the first thin film is formed on the film forming surface of the band-shaped substrate 2. Is formed. That is, the belt-like substrate 2 is conveyed along the outer peripheral surface 51 of the main roll 5 and touches the raw material gas, whereby the first thin film is formed on the film-forming surface of the belt-like substrate 2 over the longitudinal direction. The Moreover, after the conveyance speed of the strip | belt-shaped base material 2 becomes constant with the film-forming conveyance speed, the 1st thin film with a uniform film thickness is obtained.

  Further, the belt-like substrate 2 that has passed through the first film forming chamber 7a enters the second film forming chamber 7b and is exposed to the source gas in the second film forming chamber 7b, whereby the second thin film substrate 2 is formed on the first thin film. A thin film is formed. Moreover, after the conveyance speed of the strip | belt-shaped base material 2 becomes fixed with the film-forming conveyance speed, the 2nd thin film of uniform film thickness is obtained. Here, the process of forming the first thin film and the second thin film on the band-shaped substrate 2 while conveying the band-shaped substrate 2 at a constant film-forming conveyance speed is referred to as a film-forming step in this description. And after forming the 1st thin film and the 2nd thin film on the strip | belt-shaped base material 2, the strip | belt-shaped base material 2 is wound up by the conveyance roll 4. FIG.

  Next, after most of the strip-shaped substrate 2 is wound on the transport roll 4, the rotation direction of the transport roll 3 and the transport roll 4 is reversed, and the transport direction of the strip-shaped substrate 2 is reversed. At this time, the conveyance speed of the belt-like substrate 2 is once reduced, and after reaching zero, the conveyance direction is reversed, and the conveyance speed is accelerated until the conveyance speed reaches the film formation conveyance speed. In this description, the process in which the transport direction of the belt-like substrate 2 is reversed and the transport speed is lower than the film forming transport speed is referred to as a reversal step. Immediately after this inversion step, the plasma intensity control means 75 controls the voltage applied to the plasma electrode 72 to be a standby voltage.

  Next, the film intensity is controlled by the plasma intensity control means 75 so that the conveyance speed of the belt-like substrate 2 becomes constant at the film formation conveyance speed and the voltage applied to the plasma electrode 72 becomes the film formation voltage. Done. At this time, the belt-like substrate 2 passes through the second film forming chamber 7b and the first film forming chamber 7a in this order, and the first thin film is formed on the second thin film.

  Thereafter, the inversion step and the film forming step are repeatedly performed a predetermined number of times, whereby a sealing film in which a predetermined number of first thin films and second thin films are alternately stacked is formed on the band-shaped substrate 2. Is done.

  Finally, after the voltage applied to the plasma electrode 72 becomes zero and the plasma in each film forming chamber is extinguished, all of the belt-like substrate 2 is wound around one of the transport rolls, and the transport roll Is removed from the thin film forming apparatus 1 and the belt-like substrate 2 is sent to the next step.

  With the above thin film forming apparatus and thin film forming method, it is possible to obtain a substrate on which thin films are stacked with a high yield.

  In the present embodiment, the plasma intensity control means 75 is used as the heat transfer limiting means, and the voltage applied to the plasma electrode 72 in the inversion mode is lower than the film formation voltage that is the voltage in the film formation mode. By controlling the plasma intensity control means 75 to the standby voltage, the plasma intensity in the inversion mode is made lower than the plasma intensity in the film formation mode. However, the heat transfer limiting means is limited to this form. I can't. For example, as shown in FIG. 3, the heat transfer limiting means may be a shutter device 76 that shields between the film forming surface of the belt-like substrate 2 and the plasma electrode 72. The shutter device 76 is movable in the Y-axis direction (perpendicular to the paper surface), a shielding position that shields between the film formation surface and the plasma electrode 72, and the plasma movement from the plasma electrode 72 to the film formation surface. It is possible to take a stand-by position that does not hinder. According to this configuration, it is possible to form a state in which the plasma does not touch the strip-shaped substrate 2, and it is possible to reliably prevent the strip-shaped substrate from being stretched by heat during the inversion mode.

  In this embodiment, a technique for controlling the voltage applied to the plasma electrode 72 is employed as the plasma intensity control means. However, the present invention is not limited to this technique. For example, the pressure in the film forming chamber 7 can be controlled. The intensity of plasma may be controlled by a method for controlling the amount of source gas supplied into the film chamber 7.

  In the present embodiment, the case where there are two film forming chambers 7 has been described. However, by increasing the partition 62, three or more film forming chambers 7 are provided to form three or more types of thin films. May be. Alternatively, only one film forming chamber 7 may be provided to obtain a relatively thick film by laminating one kind of thin film.

DESCRIPTION OF SYMBOLS 1 Thin film forming apparatus 2 Strip | belt-shaped equipment 3 Conveyance roll 4 Conveyance roll 5 Main roll 6 Main roll chamber 7 Deposition chamber 7a 1st Deposition chamber 7b 2nd Deposition chamber 31 Core part 41 Core part 51 Outer peripheral surface 61 Vacuum pump 62 Partition Part 71 Vacuum pump 71a Vacuum pump 71b Vacuum pump 72 Plasma electrode 72a Plasma electrode 72b Plasma electrode 73 Raw material gas piping 73a Raw material gas piping 73b Raw material gas piping 74 High frequency power source 74a High frequency power source 74b High frequency power source 75 Plasma intensity control means 75a Plasma intensity control means 75b Plasma intensity control means 76 Shutter device

Claims (3)

A pair of transport rolls that reciprocate and transport the band-shaped substrate by one side sending out the band-shaped substrate and the other winding the band-shaped substrate;
A film forming chamber that surrounds a part of the film forming surface of the belt-shaped substrate and forms a closed space with a part of the film forming surface;
Source gas supply means for supplying source gas to the closed space;
A plasma electrode that is connected to a high-frequency power source and converts the source gas in the closed space into a plasma;
A thin film forming apparatus for forming a thin film containing the raw material gas as a component by applying the raw material gas converted into plasma in the film forming chamber to the film forming surface,
A film forming mode for forming a thin film on the belt-shaped substrate while conveying the belt-shaped substrate at a predetermined speed;
A reversing mode for reversing the transport direction of the belt-shaped substrate;
Have
The thin film further comprising plasma intensity control means for lowering the intensity of the plasma in the inversion mode to be lower than the intensity of the plasma in the film formation mode while maintaining the generation of the plasma. Forming equipment. The plasma intensity control means sets a voltage applied to the plasma electrode in the inversion mode as a standby voltage that is lower than a film formation voltage that is a voltage in the film formation mode. The thin film forming apparatus according to claim 1 . While reciprocating the belt-shaped substrate, it is a thin film forming method of forming a thin film containing the raw material gas as a component by applying a plasma source gas to the film-forming surface of the belt-shaped substrate,
A film forming step for forming a thin film on the band-shaped substrate while conveying the band-shaped substrate at a predetermined speed;
A reversing step for reversing the conveying direction of the belt-shaped substrate;
Have
In the inversion step, the plasma intensity is made lower than the plasma intensity in the film formation mode while maintaining the generation of the plasma .

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