TWI597383B - Structure for electronic device, plasma cvd apparatus and film forming method - Google Patents

Description

Structure for electronic device, plasma CVD device, and film formation method

The present invention relates to a plasma CVD apparatus, a film formation method by plasma CVD treatment, and a structure for an electronic device obtained by performing plasma CVD treatment.

The plasma process plays a major role in the manufacturing process of various electronic devices such as the manufacturing process of the lanthanide solar cell. For example, Patent Document 1 discloses an apparatus for forming a thin film on a substrate by plasma-enhanced chemical vapor deposition (plasma-assisted chemical vapor deposition).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-214729

More specifically, Patent Document 1 discloses a device in which a plurality of plasma sources are disposed along a transport direction of a substrate, and the substrates transferred by the roll-to-roll method are sequentially plasma-processed by the plurality of plasma sources. CVD treatment. As a result, a film corresponding to the plurality of layers of the plurality of plasma sources is formed on the substrate.

However, in the case where a thin film of a double layer is formed on a substrate, since an interface is formed between the respective layers, various defects due to the presence of the interface occur. For example, Yu Tai In the anode battery, it is preferable that the light is not introduced from the external light and is more introduced into the device. However, if an interface exists between the layers of the film on the substrate, light is reflected by the interface, thereby causing introduction. The amount of light into the device is reduced.

As a configuration in which no interface is formed in the film, a film in which a single layer is formed on the substrate can be considered. However, in this case, various defects due to a single film quality (for example, uniform refractive index) in the film may occur. For example, it is known that in a solar cell, due to the difference in refractive index between the films on the substrate, a phase difference is generated between the internally reflected light in the film, thereby reducing internal reflection as a whole and increasing introduction into the device. The amount of light, while a single layer of film cannot achieve this effect.

The present invention has been made in view of the above problems, and an object of the invention is to provide a technique for forming a film having no interface in a film and having a film quality characteristic not on a single substrate.

The invention of claim 1 is a structure for an electronic device, comprising: a substrate; and a CVD film formed on a main surface of the substrate by a plasma CVD method; and a normal line away from the main surface In the direction, the composition of the CVD film continuously changes from the first material composition to the second material composition.

The invention of claim 2 is characterized in that the type of the plurality of constituent elements included in each of the first material composition and the second material composition are common to each other. The content ratios of the plurality of constituent elements are different from each other.

The invention according to claim 1 is characterized in that the component included in the first material composition and the component included in the second material composition are different from each other.

The invention of the electronic device according to any one of claims 1 to 3, wherein the substrate is a semiconductor substrate for a solar cell, and the CVD film is a protective film for the solar cell.

The invention of claim 4 is the structure for an electronic device according to claim 4, wherein the CVD film comprises a tantalum nitride film.

According to a sixth aspect of the invention, a plasma CVD apparatus includes: a chamber; and a holding conveyance unit that holds a substrate to be processed in the chamber and relatively transports along a transport path; and a plurality of inductive coupling antennas; The first gas supply unit is disposed along the transport path in the processing space, and is arranged in a processing space defined in the chamber, and the number of windings of each is less than one turn; a first material gas is supplied to the upstream portion; and a second gas supply unit supplies a second material gas different from the first material gas to the downstream portion along the transport path in the processing space; and the first gas is supplied from the first gas The supply unit supplies the first material gas, supplies the second material gas from the second gas supply unit, and supplies high-frequency electric power to the plurality of inductive coupling antennas to generate plasma. And transporting the substrate along the transport path, thereby forming a CVD film on a main surface of the substrate, in a direction away from a normal direction of the main surface The composition of the CVD film continuously changes from the composition of the first material corresponding to the first material gas to the composition of the second material corresponding to the second material gas.

The invention of claim 6 is the plasma CVD apparatus according to claim 6, comprising: a first spacer member that is perpendicular to the plate-shaped body of the transport path, and is disposed along the transport path to form the plurality of inductors a coupling-type antenna further upstream; and a second spacer member that is perpendicular to the plate-shaped body of the transport path and disposed downstream of the plurality of inductive coupling antennas along the transport path; The first and second spacer members define the width in the transport direction of the processing space.

According to a sixth aspect of the invention, in the plasma CVD apparatus of the sixth aspect, the plurality of constituent elements included in each of the first material gas and the second material gas system are common to each other; A plurality of constituent elements have a gas content different from each other.

According to a sixth aspect of the invention, in the plasma CVD apparatus of the sixth aspect, the component contained in the first material gas and the component contained in the second material gas are different from each other.

A plasma CVD apparatus according to any one of claims 6 to 9, wherein the substrate is a semiconductor substrate for a solar cell, and the CVD film is a protective film for the solar cell.

The invention of claim 10 is characterized in that, in the plasma CVD apparatus according to claim 10, at least one of the first material gas and the second material gas contains decane and ammonia, and the CVD film contains a tantalum nitride film.

The invention of claim 12 is a film forming method characterized in that it is subjected to plasma treatment in a processing space of a plurality of inductively coupled antennas in which each of the number of windings is arranged in a circle, so as to be along the transport path a CVD film is formed on the main surface of the substrate to be transferred, and includes a first gas supply step of supplying the first material gas to the upstream portion along the transport path in the processing space, and a second gas supply step along the processing space The transport path is configured to supply a second material gas having a composition different from the first material gas to the downstream portion, and a plasma processing step of supplying high frequency power to the plurality of inductive coupling antennas to generate plasma, thereby forming the substrate Performing chemical vapor deposition formed by plasma decomposition of the first and second material gases; and carrying the step of transporting the substrate along the transport path; and forming a CVD film on the main surface of the substrate The composition of the CVD film from the first material composition corresponding to the first material gas is corresponding to the second material gas in a direction away from the normal direction of the main surface Material 2 is continuously changed.

In the structure according to any one of claims 1 to 5, a CVD film in which the composition of the second material continuously changes from the first material composition to the normal direction away from the main surface is formed on the main surface of the substrate. Since the change in the composition of the material in the CVD film is continuous, various disadvantages due to the presence of the interface are not generated (for example, due to reflection at the interface) The amount of light introduced into the device in the positive battery is reduced, etc.). Moreover, since the material composition in the CVD film continuously changes, various defects caused by a single film quality are not generated (for example, due to the absence of a refractive index difference in the film, the solar cell is introduced into the device. Light loss, etc.).

The plasma CVD apparatus according to any one of claims 6 to 11 is particularly suitable for the apparatus for obtaining the structure for an electronic device according to any one of claims 1 to 5.

The film formation method described in claim 12 is particularly suitable for obtaining a film formation method for the structure for an electronic device described in claims 1 to 5.

1‧‧‧Processing chamber

2‧‧‧ Keeping the transport department

3‧‧‧ heating department

4‧‧‧The Plasma Generation Department

5A, 5B‧‧‧ spacer members

6A~6C‧‧‧Gas Supply Department

7‧‧‧Exhaust Department

8‧‧‧Control Department

9‧‧‧Substrate

11‧‧‧Processing chamber roof

21‧‧‧Transport roller

41‧‧‧Inductively coupled antenna

42‧‧‧Feeders

43‧‧‧match box

44‧‧‧High frequency power supply

71‧‧‧Vacuum pump

72‧‧‧Exhaust piping

73‧‧‧Exhaust valve

90‧‧‧ Vehicles

100‧‧‧ Plasma processing unit

110‧‧‧CVD film

111‧‧‧The lower surface of the top plate of the processing chamber

611‧‧‧Supply source for the first material gas

612‧‧‧Pipe

613‧‧‧ valve

615‧‧‧Spray outlet

621‧‧‧The source of the second material gas

622‧‧‧Pipe

623‧‧‧Valve

625‧‧‧Spray outlet

631‧‧‧Supply source

632‧‧‧Pipe

633‧‧‧Valve

635‧‧‧Spray components

Center point of the C‧‧ ‧ segment

K‧‧‧Imaginary axis

L‧‧‧ line segment

S1‧‧‧ main face

V‧‧‧ processing space

Fig. 1 is a view schematically showing a YZ side view of a schematic configuration of a plasma processing apparatus.

Fig. 2 is a view schematically showing an XZ side view of a schematic configuration of a plasma processing apparatus.

Fig. 3 is a view for explaining the arrangement relationship of a plurality of inductive coupling type antennas.

4(a) and 4(b) are side views of the structure 10 and a view for explaining the refractive index of the CVD film 110.

Fig. 5 is a view showing the spectral reflectance of the CVD film in the structures 10, 10Y, and 10Z.

Fig. 6 is a view for explaining the refractive index of the CVD film 110 of the modification.

Hereinafter, the embodiment will be described with reference to the drawings. Further, the following embodiments are examples of the present invention and are not intended to limit the scope of the technical scope of the present invention. Further, in the drawings, for the sake of easy understanding, the size or the number of each part is exaggerated or simplified.

<1 Overall Configuration of Plasma CVD Apparatus 100>

Fig. 1 schematically shows a YZ side view of a schematic configuration of a plasma CVD apparatus 100. Fig. 2 is an end view taken along the line A-A of Fig. 1, and schematically shows an XZ side view of a schematic configuration of the plasma CVD apparatus 100. Furthermore, in the figure, in order to clarify the directional relationship, the XYZ positive with the Z axis as the vertical axis and the XY plane as the horizontal plane is appropriately labeled. Coordinated axis. Moreover, in order to prevent the illustration from becoming complicated, the gas supply unit 6C described below is omitted in FIG.

The plasma CVD apparatus 100 is a device for forming a CVD film (for example, a protective film) on a substrate 9 (for example, a semiconductor substrate for a solar cell) which is a target of a film by a plasma-enhanced chemical vapor deposition method. .

The plasma CVD apparatus 100 includes a processing chamber 1 that forms a processing space V therein, and a holding transport unit 2 that holds the substrate 9 (specifically, the substrate 9 disposed on the carrier 90) and along the transport direction (in the +Y direction shown), the heating unit 3 heats the substrate 9 to be transported, the plasma generating unit 4 generates plasma in the processing space V, and two spacer members 5A and 5B, etc. The width of the transport direction of the processing space V.

Further, the plasma CVD apparatus 100 includes gas supply units 6A to 6C that supply gas to the processing space V, and an exhaust unit 7 that discharges gas from the processing chamber 1. Further, the plasma CVD apparatus 100 includes a control unit 8 that controls each of the above-described constituent elements.

<Processing chamber 1>

The processing chamber 1 is a hollow member having a processing space V inside. Here, the processing space V is a space in which plasma CVD processing is performed by the inductive coupling type antenna 41 described below. In the present embodiment, one processing space V is formed in the section of the spacer members 5A and 5B.

The top plate 11 of the processing chamber 1 is disposed such that the lower surface 111 thereof is horizontal, and the inductive coupling type antenna 41 and the spacing members 5A, 5B are protruded from the lower surface 111 toward the processing space V (both in the following) Narrative). A heating unit 3 is disposed in the vicinity of the bottom plate of the processing chamber 1. A transport path (a path along the Y direction in the drawing) of the substrate 9 formed by the transport unit 2 is defined on the upper side of the heating unit 3. Further, on the side wall of the ±Y side of the processing chamber 1, for example, a carry-in/out port (not shown) that is opened and closed by a gate valve is provided.

<maintaining the transport unit 2>

The holding conveyance unit 2 holds the carrier 90 in a horizontal state and is formed in the processing chamber via It is carried out along the transport path by moving out of the entrance. A plurality of substrates 9 as objects to be attached to the surface of the carrier 90 are disposed on the upper surface of the carrier 90 (in the present embodiment, 9 substrates 9 in a total of 3 × 3 in the X direction and the Y direction). Further, a processing space V for performing plasma CVD processing is formed at a position above the transport path and facing a plurality of substrates 9 transported on the transport path.

Specifically, the holding transport unit 2 includes a pair of transport rollers 21 that are disposed opposite to each other with the transport path interposed therebetween, and a drive unit (not shown) that rotationally drives the transport rollers 21 in synchronization with each other. The pair of transport rollers 21 are provided, for example, in a plurality of arrays along the extending direction of the transport path (the Y direction shown). In this configuration, each of the transport rollers 21 is rotated while being in contact with the lower surface of the carrier 90 to transport the carrier 90 along the transport path. As a result, the substrate 9 held on the carrier 90 relatively moves with respect to the processing space V having the inductive coupling type antenna 41.

<heating section 3>

The heating unit 3 is a member that heats the substrate 9 that is held by the conveyance unit 2 and is placed below the holding conveyance unit 2 (that is, below the conveyance path of the substrate 9). The heating unit 3 can be constituted by, for example, a ceramic heater. Further, in the plasma CVD apparatus 100, a mechanism for cooling the substrate 9 held by the holding conveyance unit 2 or the like may be further provided.

<The plasma generating unit 4>

The plasma generating unit 4 generates plasma in the processing space V. The plasma generating unit 4 includes a plurality of (four in the present embodiment) inductive coupling type antennas 41 as inductive coupling type high frequency antennas. Specifically, each of the inductive coupling antennas 41 is formed by bending a metal tubular conductor into a U shape by a dielectric body such as quartz.

The plurality of inductive coupling type antennas 41 are arranged at intervals (preferably at equal intervals) in a predetermined direction, and are fixed with respect to the top plate 11. Fig. 3 is a partially enlarged view showing the arrangement of a plurality of inductive coupling antennas 41 in the present embodiment. As shown in FIG. 3, a plurality of inductive coupling antennas 41 are arranged in a line along the virtual axis K by arranging the center point C of the line segment L connecting the both end portions of each of them on the predetermined virtual axis K. Preferably, the imaginary axis K is in a direction crossing the transport direction (Y direction) of the substrate 9 (more preferably as shown in the figure) The axis in which the conveying direction is orthogonal (X direction) extends, and is preferably an axis extending in parallel with the side wall of the processing chamber 1 on the ±Y side.

Further, in the illustrated example, the line segment L connecting the both end portions of the inductive coupling antenna 41 is exemplified in parallel with the virtual axis K (that is, each of the plurality of inductive coupling antennas 41 is arranged in a state parallel to the arrangement direction thereof) In this case, the line segment L and the imaginary axis K may not be necessarily parallel. That is, the angle between the line segment L and the imaginary axis K may be zero or more. For example, the line segment L may also be orthogonal to the imaginary axis K. In this case, each of the inductive coupling antennas 41 is disposed in a state orthogonal to the arrangement direction thereof.

Further, in the illustrated example, four inductive coupling antennas 41 are provided along the virtual axis K, but the number of the inductively coupled antennas 41 arranged along the virtual axis K is not necessarily four, and may be according to the processing chamber 1 The size, etc., is selected as appropriate. Further, the inductive coupling type antennas 41 may be arranged in a matrix or a zigzag shape. In other words, a plurality of virtual axes K arranged at intervals in the Y direction may be defined, and a plurality of inductive coupling antennas 41 may be arranged along each of the plurality of virtual axes K.

One end of each of the inductive coupling type antennas 41 is connected to the high frequency power source 44 via the power feeder 42 and the matching box 43. Further, the other end of each of the inductive coupling type antennas 41 is grounded. In this configuration, when a high-frequency current (specifically, a high-frequency current of, for example, 13.56 MHz) flows from the high-frequency power source 44 to each of the inductive coupling antennas 41, the electric field around the inductive coupling type antenna 41 (high frequency) The electric field is induced to accelerate the electrons, thereby generating plasma (Inductively Coupled Plasma (ICP)).

As described above, the inductive coupling type antenna 41 has a U shape. The U-shaped inductively coupled antenna 41 corresponds to an inductively coupled antenna having a number of windings less than one turn, and the inductive coupling antenna having an inductance lower than one turn or more is two of the inductively coupled antennas 41. The high frequency voltage generated at the end is lowered, thereby suppressing high frequency oscillation of the plasma potential accompanying electrostatic coupling with respect to the generated plasma. Therefore, the electron loss to the ground potential accompanying the plasma potential oscillation is lowered, so that the plasma potential is suppressed particularly low. Furthermore, Such an inductive coupling type high-frequency antenna is disclosed in Japanese Patent No. 3836636, Japanese Patent No. 3836866, Japanese Patent No. 4,541,392, and Japanese Patent No. 4,852,140.

<Spacer members 5A, 5B>

The spacer member 5A (first spacer member) is a plate-shaped body that is perpendicular to the transport path, and is fixed to the lower side with respect to the top plate 11 at a position upstream of the four inductive coupling antennas 41 in the transport direction. The spacer member 5B (second spacer member) is a plate-shaped body that is perpendicular to the transport path, and is fixed to the lower side with respect to the top plate 11 at a position downstream of the four inductive coupling antennas 41 in the transport direction.

Further, the width of the spacer members 5A and 5B in the X direction is wider than the width of the four inductive coupling antennas 41 in the X direction, and the width of the spacer members 5A and 5B in the Z direction is wider than the width of the four inductive coupling antennas 41 in the Z direction. In this way, since the four inductive coupling antennas 41 are sandwiched by the two spacer members 5A and 5B having the XZ in a plan view and having a larger area than the four inductive coupling antennas 41, the processing space V for the plasma CVD process is performed. The width of the transport direction (Y direction) becomes a section of the spacer member 5A and the spacer member 5B.

<Gas supply unit 6A to 6C>

The gas supply unit 6A (first gas supply unit) includes a supply source 611 of a first material gas, and a pipe 612 having one end connected to the supply source 611 and the other end open to the upstream side in the transport direction in the processing space V. A discharge port 615 is connected. Further, a valve 613 (FIG. 1) is interposed in the path of the pipe 612. The valve 613 is preferably a valve that can automatically adjust the flow rate of the gas flowing through the pipe 612. Specifically, for example, it preferably includes a mass flow controller or the like.

In this configuration, when the valve 613 is in the open state, the first material gas supplied from the supply source 611 is ejected from the plurality of ejection ports 615 toward the upstream side in the transport direction in the processing space V. As the first material gas, for example, a mixed gas obtained by mixing a decane (SiH 4 ) gas and an ammonia (NH 3 ) gas with a first material composition can be used.

The gas supply unit 6B (second gas supply unit) includes a supply source 621 of a second material gas, and a pipe 622 having one end connected to the supply source 621 and the other end open to the downstream side in the transport direction in the processing space V. A discharge port 625 is connected. Further, a valve 623 (FIG. 1) is interposed in the path of the pipe 622. The valve 623 is preferably a valve that can automatically adjust the flow rate of the gas flowing through the pipe 622. Specifically, for example, it preferably includes a mass flow controller or the like.

In this configuration, when the valve 623 is in the open state, the second material gas supplied from the supply source 621 is ejected from the plurality of ejection ports 625 toward the downstream side in the transport direction in the processing space V. As the second material gas, for example, a mixed gas obtained by mixing a decane gas and an ammonia gas with a second material composition different from the first material composition can be used. Hereinafter, a case where the content ratio of the decane gas of the first material composition is higher than the second material composition and the ammonia gas content rate is lower than the second material composition will be described.

Further, as shown in FIG. 3, a plurality of discharge ports 615 (four in the present embodiment) and a plurality of discharge ports 625 (four in the present embodiment) in the gas supply portion 6A are shown in FIG. The plurality of inductive coupling antennas 41 (four in the present embodiment) are arranged to face each other in the Y direction.

The gas supply unit 6C includes a supply source 631 of an inert gas (nitrogen gas in the present embodiment), and a pipe 632 having one end connected to the supply source 631 and the other end and a plurality of inductive coupling type antennas 41 located in the processing space V. A plurality of ejection members 635 are connected at the upper side. Further, a valve 633 (Fig. 2) is interposed in the path of the pipe 632. The valve 633 is preferably a valve that can automatically adjust the flow rate of the gas flowing in the pipe 632. Specifically, for example, it preferably includes a mass flow controller or the like.

A plurality of ejection members 635 are arranged in a row at intervals, and are fixed to the lower surface 111 of the top plate 11 of the processing chamber 1. Specifically, for example, a plurality of ejection members 635 are respectively disposed at positions corresponding to the inductive coupling type antenna 41 (for example, a position on both sides of the U-shaped inductive coupling type antenna 41 on the virtual axis K) (ie center point C)), and relative The top plate 11 is airtightly mounted. The size of each of the ejection members 635 protruding from the lower surface 111 is set to be sufficiently smaller than the size of the inductive coupling type antenna 41 protruding from the lower surface 111.

In this configuration, when the valve 633 is in the open state, the nitrogen gas supplied from the supply source 631 is ejected from the respective discharge members 635 toward the respective inductive coupling antennas 41. As a result, since the environment around the respective inductive coupling type antennas 41 is filled with nitrogen gas, the CVD film can be prevented from being formed on each of the inductive coupling type antennas 41 even if the plasma CVD process described below is performed in the processing space V.

As described above, in the present embodiment, the gas supply unit 6A and the gas supply unit 6B are supplied with a mixed gas of decane gas and ammonia gas, and nitrogen gas is supplied from the gas supply unit 6C. The gas is discharged by the supply units 6A to 6C at a desired flow rate, and can be selected as appropriate according to the type of the film to be formed on the substrate 9, the processing conditions (temperature, pressure, etc. of the processing space V). Each of the valves 613, 623, and 633 is electrically connected to the control unit 8. Therefore, the control unit 8 controls the respective units based on the value specified by the operator or the like, and operates the discharge port 615, the discharge port 625, and the discharge member 635 which are desired by the operator from the operator's desired discharge port 615, discharge port 625, and discharge member 635. The flow rate desired by the member is introduced into the processing space V.

<Exhaust part 7>

The exhaust unit 7 is a high vacuum exhaust system, and specifically includes, for example, a vacuum pump 71, an exhaust pipe 72, and an exhaust valve 73. One end of the exhaust pipe 72 is connected to the vacuum pump 71, and the other end is connected to the processing space V in communication. Further, the exhaust valve 73 is provided in the middle of the path of the exhaust pipe 72. Specifically, the exhaust valve 73 is, for example, a valve that includes a mass flow controller or the like and that can automatically adjust the flow rate of the gas flowing through the exhaust pipe 72 . In this configuration, when the exhaust valve 73 is opened in a state where the vacuum pump 71 is actuated, the processing space V is exhausted.

<Control unit 8>

The control unit 8 is electrically connected to each constituent element included in the plasma CVD apparatus 100 (shown schematically in FIG. 1), and controls the respective elements. Specifically, the control unit 8 is, for example, a general electric The general computer is a ROM (Read Only Memory) such as a CPU (Central Processing Unit) or a memory program that performs various arithmetic processing by a bus line or the like, and is subjected to arithmetic processing. A hard disk such as a RAM (Random Access Memory) in a work area, a memory program, or various data files, and a data communication unit having a data communication function via a LAN (Local Area Network) or the like Connected. Further, the control unit 8 is connected to a display for performing various displays, an input unit including a keyboard, a mouse, and the like. In the plasma CVD apparatus 100, predetermined processing is performed on the substrate 9 under the control of the control unit 8.

<2 Process of Processing>

Next, a flow of processing performed in the plasma CVD apparatus 100 will be described with reference to FIG. 1. The processing described below is executed under the control of the control unit 8.

When the carrier 90 on which the substrate 9 is placed is carried into the processing chamber 1 through the loading and unloading port of the processing chamber 1, the holding unit 2 holds the carrier 90. Further, the exhaust unit 7 discharges the gas in the processing chamber 1 to set the processing chamber 1 to a vacuum state. Further, at a predetermined timing, the conveyance unit 2 starts the conveyance of the carrier 90 (transfer step), and the heating unit 3 starts heating of the substrate 9 disposed on the carrier 90.

When the inside of the processing chamber 1 is in a vacuum state, the gas supply unit 6A starts to supply the first material gas (first gas supply step) from the discharge port 615 to the upstream side (−Y side) in the transport direction of the processing space V, and the gas The supply unit 6B starts to supply the second material gas from the discharge port 625 to the downstream side (+Y side) in the transport direction of the processing space V (second gas supply step). Thereby, an environment in which the space filled with the first material gas continuously changes from the space in which the first material gas is filled to the space in which the second material gas is filled is formed in the processing space V from the upstream side to the downstream side.

Further, the gas supply unit 6C supplies an inert gas to each of the inductive coupling antennas 41 from the discharge member 635. Thereby, the surrounding environment of each of the inductive coupling type antennas 41 in the processing space V is filled with the inert gas.

Moreover, the coupling from the high frequency power source 44 to the respective inductors is started at the same time as the supply of the gases is started. The antenna 41 flows a high-frequency current (specifically, for example, a high-frequency current of 13.56 MHz). Thus, the electrons are accelerated by the high-frequency induced electric field around the inductively coupled antenna 41, thereby generating an inductively coupled plasma. When the plasma is generated, the first material gas and the second material gas in the processing space V (in the present embodiment, both are a mixed gas of decane gas and ammonia gas) are plasma-decomposed to be transferred to the substrate 9 to be transported. Chemical vapor deposition (plasma processing step) is performed.

The substrate 9 in which the CVD film (the tantalum nitride film in the present embodiment) is formed on the main surface can be used as various electronic devices such as solar cells as the electronic device structure 10 (FIG. 4). Further, in the present embodiment, since the surrounding environment of each of the inductive coupling antennas 41 is filled with the inert gas supplied from the gas supply unit 6C, the CVD film is not formed on the surface of each of the inductive coupling antennas 41, thereby preventing the cause of A decrease in antenna performance caused by forming a CVD film on the surface of each inductive coupling type antenna 41 is obtained.

<3 Structure 10>

Fig. 4 (a) is a side view showing the structure 10 produced by the plasma CVD apparatus 100 of the present embodiment. Fig. 4(b) is a view showing the relationship between the distance from the principal surface S1 and the refractive index in the normal direction (Z direction) in the CVD film 110 of the structure 10.

As described above, the inside of the processing space V is formed from the upstream side to the downstream side, and the space filled with the first material gas continuously changes to the space filled with the second material gas, and the surface is in the processing space V. The plasma CVD process is performed while transferring the substrate 9 to the position.

Therefore, the composition of the CVD film 110 formed on the main surface of the substrate 9 becomes a composition that continuously changes from the first material composition to the second material composition in the normal direction away from the main surface.

Further, in the present embodiment, the content of the decane gas of the first material composition is higher than the composition of the second material, and the content of the ammonia gas is lower than the composition of the second material. As a characteristic of the tantalum nitride film, the higher the refractive index is, the higher the refractive index is. Therefore, in the CVD film 110, the refractive index of the main surface S1 side of the substrate 9 in the normal direction is higher than that in the normal direction. The upper surface is opposite to the main surface S1 of the substrate 9. The opposite side (Fig. 4(b)). More specifically, the CVD film 110 obtained in the present embodiment has a first interval D1 having a point P1 (refractive index of 2.5) and a relatively high refractive index in the normal direction away from the main surface S1 of the substrate 9. a second section D2 having a point P2 (refractive index of 1.8) and a relatively low refractive index; and a third section D3 having a point P3 (refractive index of 2.3) and having a first interval D1 and a second interval D2 The refractive index in the middle.

As described above, in the present embodiment, the CVD film 110 formed on the principal surface S1 of the substrate 9 is configured to continuously change in material composition away from the normal direction of the main surface, and thus has a CVD film different from that composed of a single material. Or the film quality of the CVD film at the interface between the composition of one material and the composition of the other material (the change in material composition is discontinuous).

Hereinafter, an example of the effect of the structure 10 of the present embodiment will be described by exemplifying the reflectance of the structure 10 when the light is irradiated from the outside.

FIG. 5 is a view showing a structure 10 of the present embodiment, a substrate having a single-layer CVD film formed on its surface (hereinafter referred to as a structure 10Y), and a substrate having two CVD films having different refractive indices on the surface ( Hereinafter, the structure of the structure 10Z) is a graph of the spectral reflectance when the CVD film is irradiated with light from the outside of each structure. In addition, when calculating the spectral reflectance shown in FIG. 5, it is premised that in the structures 10, 10Y, and 10Z, the CVD film formed on the main surface of each is a tantalum nitride film of the same thickness. And the integral value of the refractive index of the CVD film formed on the main surface of each of the same is the same.

As shown in FIG. 5, in the wavelength region of 250 nm (nano, hereinafter the same) to 1050 nm, the reflectance of the structure 10 of the present embodiment is lower than that of the structure 10Z having two CVD films. The reason for this is that the composition of the CVD film 110 is a composition that continuously changes from the first material composition to the second material composition, and there is no interface between the different material compositions in the CVD film 110. In other words, when light of a wavelength region of 250 nm to 1050 nm is irradiated from the outside of the structure, a part of the light is reflected at the interface between the two CVD films having different refractive indices in the structure 10Z, and is in the structure 10 However, there is no reflection of light generated by the interface, which in turn causes a decrease in the reflectance of light.

As described above, in the structure 10 of the present embodiment, the reflectance of light from the outside is lower than the structure 10Z in which two CVD films are formed on the substrate 9 (more generally, a CVD film in which a complex layer is formed) The structure is particularly suitable for an electronic device having a low reflectance as a solar cell.

Further, as shown in FIG. 5, in the wavelength region of 300 nm to 700 nm, the structure 10 of the present embodiment has a lower reflectance than the structure 10Y having a single-layer CVD film. The reason is considered to be that there is a difference in refractive index between the CVD film 110. In such a film, it is known that, in addition to the reflection of the surface of the film or the interface between the film and the film, internal reflection is usually generated in the film, but each of the films is caused by the difference in refractive index in the film. The internally reflected light produces a phase difference that reduces internal reflection as a whole. In other words, when the light of the wavelength region of 300 nm to 700 nm is irradiated from the outside of the structure, the structure 10Y does not exhibit the effect of reducing the internal reflection of light, and in the structure 10, there is refraction in the film. The difference in height is reduced by the internal reflection of light, which in turn causes a decrease in the reflectance of light. Further, in the wavelength region of 250 nm to 300 nm and 700 nm to 1050 nm, the reflectance of the structure 10Y having a single-layer CVD film is lower than that of the structure 10 of the present embodiment. Regarding this point, the reasons for this have not been examined.

As described above, in the structure 10 of the present embodiment, the reflectance of light in the wavelength region of 300 nm to 700 nm is lower than that of the single-layer structure 10Y, and it is particularly suitable for the low reflectance as in the solar cell in the wavelength region. Electronic device.

In addition, the plasma CVD apparatus 100 of the present embodiment can form a processing space V (a row of inductive coupling type antenna 41) on the substrate by forming an environment in which the inside of the processing space V continuously changes from the upstream side to the downstream side of the transport. A CVD film 110 is formed on 9. Therefore, in the plasma CVD apparatus 100 of the present embodiment, it is not necessary to form a plurality of processing spaces V in the transport direction of the substrate 9 as in the case where a plurality of CVD films are formed on the substrate 9, thereby realizing space saving and energy saving. .

<4 change example>

The embodiments of the present invention have been described above, but the present invention can be variously modified in addition to the above, without departing from the scope of the invention.

In the above embodiment, the description has been made on the case where only one processing space V is formed inside the processing chamber 1. However, the present invention is not limited thereto, and a plurality of processing spaces V may be formed in the processing chamber 1. Aspect. In this case, if the materials having different material compositions on the upstream side and the downstream side are supplied to the inside of at least one of the processing spaces V in the plurality of processing spaces V, the main body of the substrate 9 may be similar to the above-described embodiment. A CVD film 110 in which the material composition continuously changes in the normal direction is formed on the surface S1.

Further, in the above-described embodiment, the types (the decane and the ammonia) of the plurality of constituent elements contained in the first material gas and the second material gas are common to each other, and the content ratios of the plurality of constituent elements are different from each other. The situation has been explained, but it is not limited to this.

For example, in the case where the constituent elements contained in the first material gas are decane and nitrogen monoxide, and the constituent elements contained in the second material gas are decane and ammonia, the constituent elements contained in the first material gas may be The components contained in the second material gas are different from each other. In this case, the material of the CVD film formed on the principal surface S1 of the substrate 9 is continuously changed from the yttrium oxide film to the tantalum nitride film in the normal direction away from the main surface S1.

Further, in the above-described embodiment, an inert gas (nitrogen gas) is ejected from the ejecting member 635, and the surrounding environment of the inductive coupling antenna 41 is filled with an inert gas, thereby preventing the formation of a CVD film on the inductive coupling antenna 41. The description is, but not limited to, this. The gas ejected from the ejecting member 635 may also be a material gas in the plasma CVD process, and may also be an additive gas. Further, it is also possible that the gas is not ejected from the ejecting member 635.

Further, in the above-described embodiment, as shown in FIG. 4(b), the first section D1 having a relatively high refractive index and the relatively low refractive index are provided in the normal direction away from the principal surface S1 of the substrate 9. The CVD film 110 of the second section D1 and the third section D3 having the refractive index intermediate to the middle of the first section D1 and the second section D2 has been described, but the invention is not limited thereto.

Similar to the above embodiment, even a material formed by the first material gas The plasma CVD treatment is performed in a state where the refractive index of the composition is higher than that of the material formed by the second material gas, and the temperature of the processing space V, the pressure, and the width of the processing space V (the spacer member) can also be adjusted. Between the 5A and 5B intervals, the output of the inductive coupling type antenna 41, and the supply amount of the material gas, as shown in FIG. 6, a CVD film having no section corresponding to the second section D2 is formed.

In the above, the electronic device structure, the plasma CVD device, and the film forming method of the embodiment and its modifications have been described. However, these are examples of preferred embodiments of the present invention, and are not limited to the practice of the present invention. range. The present invention can be combined with any of the free combinations of the embodiments or any of the constituent elements of the respective embodiments within the scope of the invention, or any constituent elements are omitted in the respective embodiments.

1‧‧‧Processing chamber

2‧‧‧ Keeping the transport department

3‧‧‧ heating department

4‧‧‧The Plasma Generation Department

5A, 5B‧‧‧ spacer members

6A, 6B‧‧‧ Gas Supply Department

7‧‧‧Exhaust Department

8‧‧‧Control Department

9‧‧‧Substrate

11‧‧‧Processing chamber roof

21‧‧‧Transport roller

41‧‧‧Inductively coupled antenna

42‧‧‧Feeders

43‧‧‧match box

44‧‧‧High frequency power supply

71‧‧‧Vacuum pump

72‧‧‧Exhaust piping

73‧‧‧Exhaust valve

90‧‧‧ Vehicles

100‧‧‧ Plasma processing unit

611‧‧‧Supply source for the first material gas

612‧‧‧Pipe

613‧‧‧ valve

615‧‧‧Spray outlet

621‧‧‧The source of the second material gas

622‧‧‧Pipe

623‧‧‧Valve

625‧‧‧Spray outlet

V‧‧‧ processing space

Claims (7)

A plasma CVD apparatus comprising: a chamber; a holding transport unit that holds a substrate to be processed in the chamber and transports the substrate along the transport path; a plurality of inductive coupling antennas, and the transport path The first gas supply unit supplies the first material to the upstream portion along the transport path in the processing space in a processing space defined in the chamber, and the number of windings of each is less than one turn; a gas; and a second gas supply unit that supplies a second material gas different from the first material gas to the downstream portion along the transport path in the processing space; and supplies the first material from the first gas supply unit The material gas is supplied to the second material gas from the second gas supply unit, and the high-frequency electric power is supplied to the plurality of inductive coupling antennas to generate plasma, and the transport unit is transported along the transport path by the holding transport unit. a substrate, wherein a CVD film is formed on a main surface of the substrate, and the composition of the CVD film is self-corresponding in a direction away from a normal direction of the main surface The first material of the first material to the composition of the gas corresponding to the second material of the second material gas composition changes continuously. The plasma CVD apparatus according to claim 1, comprising: a first spacer member that is perpendicular to the plate-like body of the transport path, and disposed on the upstream side of the plurality of inductive coupling antennas along the transport path; And a second spacer member disposed perpendicular to the plate-shaped body of the transport path and disposed downstream of the plurality of inductive coupling antennas along the transport path; and by the first and second spacer members Specify the transport direction of the above processing space The width of the upper. The plasma CVD apparatus according to claim 1, wherein the types of the plurality of constituent elements included in each of the first material gas and the second material gas system are common to each other, and the content ratio of the plurality of constituent elements is not The same gas. The plasma CVD apparatus according to claim 1, wherein the constituent elements contained in the first material gas and the constituent elements included in the second material gas are different from each other. The plasma CVD apparatus according to any one of claims 1 to 4, wherein the substrate is a semiconductor substrate for a solar cell, and the CVD film is a protective film of the solar cell. The plasma CVD apparatus according to claim 5, wherein at least one of the first material gas and the second material gas contains germane and ammonia, and the CVD film includes a tantalum nitride film. A film forming method for performing plasma processing in a processing space of a plurality of inductively coupled antennas in which each of the windings is arranged in a circle, so as to be carried on the main surface of the substrate transported along the transport path Forming a CVD film thereon; further comprising: a first gas supply step of supplying a first material gas to the upstream portion along the transport path in the processing space; and a second gas supply step of the transport path pair in the processing space a downstream portion supplies a second material gas different from the first material gas; and a plasma processing step of supplying high frequency power to the plurality of inductive coupling antennas to generate a plasma, thereby performing the first step on the substrate a chemical vapor deposition formed by decomposition of a plasma of the second material gas; and a transfer step of transporting the substrate along the transfer path; and forming a CVD film on the main surface of the substrate, away from the main surface In the line direction, the composition of the CVD film is continuously changed from the composition of the first material corresponding to the first material gas to the composition of the second material corresponding to the second material gas. .