JPH04116173A - Thin film producing apparatus - Google Patents

Abstract

PURPOSE:To stabilize the plasma in a vacuum chamber and to stably form a high-purity thin film on a substrate by constituting the heater mounted with the substrate in the vacuum chamber of the thin film producing apparatus in such a manner that the heater can be moved and the exposure of the feeders to the heater is averted within the vacuum chamber. CONSTITUTION:After the atm. gas in the vacuum vessel 1 is discharged from a discharge port, gaseous SiH4 is supplied as a reaction gas from a supply port. The power source of the heater 4 is then turned on and the temp. of the substrate 5 is regulated to 200 to 300 deg.C. A high-frequency power source 20 is turned on to impress a high-frequency voltage between electrodes 19 and to generate the plasma between the electrodes 19 and the heater 4. The gaseous SiH4 is then cracked to Si and H2 by the plasma and the formed Si deposits on the substrate 5. The thin film of the Si is thus formed. The plasma is stabilized by vertically moving the heater 4 by the rotation of a handle 22 if the plasma is unstable. The voltage is impressed to the feeders 7, 8 and an electric heating wire 15 during the operation of the heater 4 but these wires do not exist in the plasma generating position and, therefore, the cracking of the coating and the intrusion thereof into the thin film do not arise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thin film manufacturing apparatus used for manufacturing thin films used in solar cells, semiconductor transistors, and the like.

[Prior Art] A conventional thin film manufacturing apparatus will be described with reference to FIGS. 4 and 5.

FIG. 4 is a cross-sectional view of the vacuum container including the heater taken parallel to the heater.

In FIG. 4, the thin film manufacturing apparatus includes a vacuum container 101 consisting of a vacuum container 101 and a heater 104. An exhaust port 102 is provided at the bottom of the vacuum container 101, a supply port 103 is provided at the top, and a current is introduced into the top surface. A terminal 109 is provided. The exhaust port 102 is connected to the vacuum container 1
Exhaust the gas in 01. The supply port 103 is connected to the vacuum container 10
A reactant gas, which is a raw material for a thin film, is supplied into the chamber. The current introduction terminal 109 is connected to a heater heating power source (not shown) via a power supply line 110.

Power supply line 110 is connected to power supply lines 107 and 108. Power supply lines 107 and 108 transmit power from a heater power source (not shown) to the heater 104. Power supply line 107
, 108 are coated with an insulator.

The current introduction terminal 109 and the vacuum container 101 are connected to an O ring 111.
It is sealed by.

The heater 104 is fixed inside the vacuum container 101 by a jig 10B. Substrates 105 are arranged on both sides of the heater 104 . This substrate 105 is made of glass or the like. On this substrate 105, a reactive gas decomposed by the plasma is deposited as a thin film.

FIG. 5 is a cross-sectional view of the thin film manufacturing apparatus shown in FIG. 4 taken perpendicularly to the heater 104.

A pair of electrodes 112 are fixed to the center of the side surface of the vacuum container 101. These electrodes 112 are made of an insulator 114
It is insulated from the vacuum container 101 by.

The electrode 112 is connected to a high frequency power source 113 for plasma generation. In addition, a high frequency power source 113 for plasma generation
The heater 104 is grounded.

A heating wire 115 is provided inside the heater 104 . This heating wire 115 is the power supply line 107, Log
It is connected to the.

Next, the operation of the conventional thin film manufacturing apparatus will be explained.

First, the vacuum container 101 is sealed, and an exhaust device (not shown) is used to exhaust atmospheric gas from the vacuum container 101 to the exhaust port 1.
Exhaust from 02. Thereafter, after the pressure inside the vacuum container 101 reaches 10-5 to 10-Torr, the supply port 10
3. Reactive gas (for example, silane (SI
H4) gas) is supplied, and the exhaust device is adjusted so that the pressure inside the vacuum container 101 is several Torr.

Next, the heater power supply (not shown) is turned on, and the heating wire 1
15 is heated. The heating temperature of the heating wire 115 is
The temperature is adjusted to 200-300°C. Next, the high frequency power supply 113 is turned on, and plasma is generated between the electrode 112 and the heater 104. In order to stabilize the generated plasma, the high frequency power source 11 is adjusted such that the output of the high frequency power source 113 is 100 to 300 watts.
3 is adjusted.

Silane gas is decomposed into silicon and hydrogen gas by plasma, and silicon is deposited on the substrate 105.
A thin film is formed on top.

[Problem to be solved by the invention] In the thin film manufacturing apparatus having the configuration shown in the 1m4 diagram and FIG. 5,
There is a problem in that the coverings of the power supply lines 107 and 101+ are decomposed by the plasma and mixed into the formed thin film as impurities, deteriorating the quality of the thin film.

Furthermore, if the power supply lines 107 and 10B are not coated with an insulating liquid, plasma will be violently generated around the power supply lines 107 and 108, and the power supply lines 1-07 and 10g will be decomposed by the plasma, and eventually the power supply lines 1-07 and 10g will be decomposed by the plasma. There is a problem that the electric wires 107 and 108 are cut.

In addition, the connection portion between the heater 104 and the power supply lines 107 and 108, and the connection between the power supply lines 107 and 108 and the current introduction terminal 10
Is it necessary to apply an insulating coating to the connection part 9?

However, in conventional thin film manufacturing equipment, the heater 1
The heater 104 is fixed to the vacuum vessel 101 by a jig 106, and it is necessary to frequently attach and detach the heater 104 from the vacuum vessel 101 in order to adjust the position of the heater 104. However, this attachment/detachment operation causes a problem of poor insulation at the connection portion, which may cause the heater 104 to malfunction.

Furthermore, in the conventional thin film manufacturing apparatus, there are cases where the plasma generated between the electrode 112 and the heater 1'04 becomes unstable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thin film manufacturing apparatus that can be adjusted so that the plasma generated in the vacuum container 101' is stabilized.

Another object of the present invention is to provide a thin film manufacturing apparatus that can form a thin film with high purity.

[Means for Solving the Problems] In order to achieve the above object, a thin film manufacturing apparatus according to a first aspect of the present invention includes a vacuum vessel to which a gas serving as a raw material for a thin film is supplied, and a a heater for heating the substrate on which the thin film is to be formed; a plasma generating means for generating plasma in the vacuum container to decompose the raw material gas and forming the thin film on the substrate; In order to stabilize the state of the plasma generated by the plasma generating means, a moving means for moving the relative position of the heater with respect to the plasma generating means is provided.

In addition, in order to achieve another object of the present invention, a thin film manufacturing apparatus according to a second aspect of the present invention includes a vacuum vessel to which a gas serving as a raw material for the thin film is supplied, and a vacuum vessel provided within the vacuum vessel, a heater for heating a substrate on which a thin film is to be formed; a plasma generating means for generating plasma in the vacuum container to decompose the raw material gas and forming the thin film on the substrate; It is characterized by comprising a tube that passes through the tube in an airtight manner and is connected to the heater in an airtight manner, and a power supply line that passes through the tube and supplies power to the heater.

[Function] The thin film manufacturing apparatus according to the first aspect of the present invention is equipped with a moving means, so if plasma generation is unstable during thin film formation, the heater can be moved to stabilize the plasma. . Therefore, plasma can be generated stably at all times and a thin film can be stably formed.

In the thin film manufacturing apparatus according to the second aspect of the invention, the power supply line that supplies power to the heater passes through the tube and is not located inside the vacuum vessel. Therefore, it is possible to prevent the problem of the coating of the power supply line being decomposed by the plasma and being mixed into the thin film, and it is possible to form a highly pure thin film. It also makes it easier to insulate the power supply line.

[Embodiment] A thin film manufacturing apparatus according to an embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view of a vacuum container including a heater taken parallel to the heater.

In FIG. 1, the thin film manufacturing apparatus of this embodiment is comprised of a vacuum container 1 and a heater 4.

The vacuum container 1 is provided with an exhaust port 2 and a supply port 3.

The exhaust port 2 is provided at the lower side of the vacuum container 1 and exhausts the gas inside the vacuum container 1. Supply port 3 is vacuum container 1
It is provided on the upper side of the vacuum vessel I, and supplies a reaction gas, which is a raw material for thin film production, into the vacuum vessel I.

A seal flange 16.0 is provided on the top protrusion of the vacuum container 1.
Ring 11.12.17, Button ring 13, O-ring holding fitting 14, Cap 2L screw 18, Handle 22
, a ring 23 are provided.

The seal flange IB has screws 1 attached to the top protrusion of the vacuum container 1.
It is fixed by 8. The O-ring 17 is provided between the seal flange 16 and the upper protrusion of the vacuum container 1, and maintains a seal between the seal flange 16 and the empty container 1.

Further, the upper outer side of the seal flange 16 is threaded and engages with the thread formed on the lower inner side of the cap 21. Thereby, the cap 21 is rotatably held on the seal flange 16.

A wedge-shaped O-ring retainer 14 is provided below the cap 21. O-ring retainer 14 is cap 21
and a seal flange 16 and a steel pipe 10 which will be described later. Furthermore, between the seal flange 16 and the steel pipe 10, an O-ring 11, a bushing ring 13,
The O-rings 12 are arranged in this order.

The O-rings 11 and 12 are pressed by the tip of the O-ring retainer 14 and become flat, thereby sealing between the seal flange 16 and the steel pipe 10.

A steel pipe 10 is inserted into the vacuum vessel 1 by passing through the seal flange 16 and the upper surface of the vacuum vessel 1. This steel pipe 10
A flexible tube 9 is airtightly connected to the lower end, and the lower end of the flexible tube 9 is airtightly fixed to the upper surface of the heater 4.

The outer peripheral surface of the steel pipe 10 is threaded at a portion closer to the atmosphere than the O-ring 11. The nozzle 22 is rotatably attached to the seal flange 16 via a ring 23. The handle 22 includes a threaded portion that engages with a thread formed on the outer peripheral surface of the steel pipe 10. As a result, when the handle 22 is rotated, the steel pipe 10 moves up and down, and the heater 4 connected to the steel pipe 10 also moves up and down.

As mentioned above, one end of the flexible pipe 9 is connected to the steel pipe 10,
The other end is hermetically welded to the heater 4, and the connecting portion between the flexible tube 9 and the steel tube 10 and the connecting portion between the flexible tube 9 and the heater 4 are sealed. The flexible tube 9 is a bellows tube with a wall thickness of 2 mm to 2 mm, and is expandable and contractible (expansion and contraction of about 5 mm) and bendable.

The heater 4 is placed inside the vacuum container 1, and has a substrate 5 on both sides of the heater 4, and a heating wire 1 (described later) inside the heater 4.
5 are provided.

The substrate 5 is made of an insulating material such as glass. Silicon formed by plasma is deposited on the substrate 5 .

In this embodiment, the upper end of the steel pipe 10 is open, and the inside of the steel pipe IO and the heater 4 are filled with air. A power supply line 7.8 runs through the steel pipe IO and the flexible pipe 9. The power supply lines 7 and 8 supply power to the heater 4 . Further, the surface of this power supply line 7.8 is coated with an insulator.

FIG. 2 is a sectional view of the thin film manufacturing apparatus shown in FIG. 1 taken perpendicularly to the heater 4. As shown in FIG.

In FIG. 2, a pair of electrodes 19 for plasma generation are fixed on both sides of a vacuum vessel l with an insulator. The insulator seals between the vacuum container 1 and the electrode 19. The electrode [9] is connected to a high frequency power source 20 for plasma generation. The high frequency power source 20 for plasma generation grounds the steel pipe 10 and the heater 4.

The heating wire 15 is provided inside the heater 4 and is connected to the power supply line 7.8. This heating wire 15 consists of a single resistance wire or the like.

Incidentally, an observation window (not shown) is provided in the vacuum container 1 at a position where the inside of the vacuum container 1 can be seen as shown in FIG. This observation window (not shown) is made of quartz glass or the like.

Next, the operation of the thin film manufacturing apparatus according to the above embodiment will be explained.

Atmospheric gas in the vacuum container 1 is exhausted from the exhaust port 2 by an exhaust device (not shown). The seal between the steel tube 10 and the vacuum vessel l is then maintained by O-rings 11, 12. In other words, the cap 21 is
4 is rotated in the downward direction, the O-ring 1112 is sandwiched between the O-ring retainer 14, the seal flange 16, and the bushing ring 13, and becomes flattened and tightly contacts the inner surfaces of the steel pipe 10 and the seal flange 16. , the space between the steel pipe lO and the seal flange 16 is sealed.

After that, the pressure inside the vacuum container l is increased, for example, from 10-5 to
After reaching 10-6 Torr, the reaction gas is supplied from the supply port 3. In this example, 5IH4 (
silane) gas. The pressure inside the vacuum container l is several To
An exhaust system (not shown) is adjusted so that rr. Next, the power source of the heater 4 (not shown) is turned on, and the temperature of the heating wire 15 and the temperature of the substrate 5 are 200 to 300°C.
It is adjusted so that Next, the high frequency power supply 2D is turned on, a high frequency voltage is applied between the electrodes 19, and plasma is generated between the electrodes 19 and the heater 4. Silane gas is decomposed into silicon and hydrogen by the above plasma,
The generated silicon is deposited on the substrate 5, and a thin film of silicon is formed on the substrate 5.

If the plasma becomes unstable during the thin film manufacturing process,
Thin films cannot be formed stably. Therefore, for example, by periodically checking the state of the plasma, and when the plasma is unstable, by rotating the handle 22, the steel pipe lO
is moved up and down, and the heater 4 is moved up and down to stabilize the plasma.

Due to the movement of the steel pipe 10, the steel pipe IO and O-ring 11.12
Since the O-rings 11 and 12 will be sliding, the degree of collapse of the O-rings 11 and 12 should be adjusted in advance to prevent air from leaking due to this sliding.

In addition, whether the plasma is unstable or not when it is generated can be determined by observing it with the naked eye through an observation window provided in the vacuum container L, by performing spectroscopic decomposition of the plasma emission spectrum, and by comparing the emission intensity. , can be judged.

The density of the plasma, which most affects the stability and instability of the plasma, is determined by the area of the opposing portion of the electrode 19 and the heater 4. For example, if the heater 4 is moved downward from the state shown in FIG. 2, the opposing area between the electrode 19 and the heater 4 will decrease, and therefore the plasma density will be higher than when the heater 4 is not moved. state or change. In this way, by moving the heater 4 up and down as described above, the plasma state can be changed, and a stable plasma state can be found by the above-described observation method. Therefore, it is possible to continue forming a thin film while plasma is stably generated.

Furthermore, if the steel pipe 10 is tilted for some reason, the flexible tube 9 expands, contracts, and bends due to the weight of the heater 4, and the heater 4 remains parallel to the electrode 9.

While the heater 4 is in operation, the power supply lines 7 and 8 and the heating wire 15
When a voltage is applied to the steel pipe 7 and the heater 4, since the inside of the steel pipe and the heater 4 are filled with air, which is an insulator, the power supply line 7,
8 insulation is well done. Furthermore, since there is no power supply line at the plasma generation location, there is no possibility that the coating will be decomposed and mixed into the thin film.

By the above method, a thin film is stably formed, and when the thin film reaches a predetermined thickness or a certain period of time for forming the thin film, the thin film manufacturing process ends.

Since the thin film manufacturing apparatus of this embodiment is configured as described above, it produces the effects described below.

Since the feeder line 7.8 passes through the tube IO, the coating covering the feeder line 7.8 is not mixed into the thin film as an impurity, and a very high quality thin film can be formed. In addition, the power supply line 7
．． Since the feeder line 7.8 passes through the steel pipe 10, an inexpensive rubber material or the like can be used as the covering material for the feeder line 7.8. Further, since no power supply line or the like is located in the vacuum portion, it is possible to reduce failures of the thin film manufacturing apparatus. Furthermore, by moving the heater during thin film formation, the state of the plasma can be adjusted and the thin film can be stably manufactured.

FIG. 3 shows the results of comparing the concentrations of impurity components (oxygen, carbon) in a silicon thin film actually manufactured using the conventional technique and a silicon thin film actually manufactured according to an embodiment of the present invention. The thin film formed in the above example was formed using conventional technology.
The concentrations of oxygen and carbon components were lower than in the formed thin film, and it was confirmed through experiments that a highly pure thin film could be formed according to this example.

Note that the present invention is not limited to the above embodiments.

For example, in the above embodiment, a case where a silicon layer is formed on a substrate is shown, but the present invention can also be applied to a silicon alloy thin film such as a silicon nitride thin film, a silicon oxide thin film, a silicon carbide thin film, etc. other than a silicon layer. It can also be applied to manufacturing. In the above example, steel pipe 1
0 may be open to the atmosphere, or the upper end of the steel pipe 10 may be sealed. Further, for example, the heater 4 and the steel pipe 10 may be filled with insulating oil or insulating gas.

Further, the material of the tube 10 may be other than steel, such as stainless steel. Further, materials other than metal can be used as long as the vacuum container 1 can be sealed and is not easily corroded by plasma.

Moreover, the heating wire 15 provided in the heating heater 4 is not limited to - resistance wires, but it is also possible to use a coiled resistance wire.

The cross section of the tube 10 does not have to be circular, and may be polygonal, for example.

In order to stabilize the plasma, in the above embodiment, the heater 4 was moved or the electrode 19 was moved.
may be configured. The key is to configure the device so that the facing area of the heater 4 and the electrode 19 can be changed while maintaining the vacuum state.

Further, in the above embodiment, a configuration is shown in which the heater 4 is manually moved by rotating the handle 22, but the heater 4 may be moved automatically using a motor or the like. .

Further, the configuration for moving the heater 4 is as follows.
It is not limited to the configuration shown in the figure. For example, the heater 4 may be moved by providing a stage below the heater 4 and adjusting the height of this stage.

Further, the heater 4 and the steel pipework 0 may be set to a voltage other than the ground voltage.

[Effects of the Invention] The thin film manufacturing apparatus of the present invention can move the heater so that plasma is stabilized. Therefore, plasma can be generated stably at all times and a thin film can be stably formed. Furthermore, since the feeder line passes through the tube, it is possible to prevent the problem of the coating of the feeder line being decomposed by plasma and being mixed into the thin film, and a highly pure thin film can be formed. Additionally, the power supply line can be easily insulated.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the configuration of a thin film manufacturing apparatus according to an embodiment of the present invention, and FIG. A diagram showing the concentration of impurity components (oxygen, carbon) in the depth direction, and FIGS. 4 and 5 are cross-sectional views showing the configuration of a conventional thin film manufacturing apparatus. 1.101...Vacuum container, 2.102...Exhaust port,
3,103,=supply port, 4,104...heater, 5,105...substrate, 7.8,107,108,1
10... Power supply line, 9... Flexible tube, IO...
・Steel pipe, II, ! 2.17. III...O-ring, I3...button ring, 14...0-ring retainer, 15,115...heating wire, 16...seal flange, 18...screw, 19.112.・Electrode, 2
0,113...High frequency power supply for plasma generation, 21...
・Cap, 22...handle, 23...ring. Applicant Representative Patent Attorney Takehiko Suzue

Claims (2)

[Claims] (1) A vacuum vessel to which a gas serving as the raw material for the thin film is supplied; a heater provided in the vacuum vessel to heat the substrate on which the thin film is formed; and a heater that generates plasma in the vacuum vessel to supply the raw material a plasma generating means for decomposing the gas to form the thin film on the substrate; and a relative position relative to the plasma generating means before the heater in order to stabilize the state of the plasma generated by the plasma generating means. A thin film manufacturing apparatus characterized by comprising: a means for moving; and a means for moving. (2) a vacuum container to which gas that is a raw material for the thin film is supplied; a heater that is provided in the vacuum container and heats the substrate on which the thin film is to be formed; and a heater that generates plasma in the vacuum container and supplies the raw material a plasma generating means for decomposing the gas to form the thin film on the substrate; a tube hermetically passing through the vacuum container and hermetically connected to the heater; passing through the tube; A thin film manufacturing apparatus comprising: a power supply line that supplies power to the heater.