JP3207611B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device in which a part of the surface is removed in a line in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art Manufacturing a semiconductor device such as a photovoltaic element includes the steps of forming a thin film on a substrate or the like and removing a part of the thin film in a line. May be Also, in a manufacturing process of a semiconductor device using a semiconductor wafer such as a silicon wafer, a part of the surface of the semiconductor wafer may be removed in a line shape. Conventionally, such thin films and surface layers have been removed.
Ablation by energy beam such as chemical etching or laser beam is used. In the case of chemical etching, there are problems such as the complexity of the manufacturing process and the low processing speed.When an energy beam such as a laser beam is used, the thin film or the like is heated by the irradiation of the energy beam. In addition, there is a problem that a thin film or the like is thermally damaged.

Japanese Patent Publication No. 62-14954 discloses a structure of an integrated solar cell. In such a solar cell, a metal oxide such as an amorphous silicon thin film, a metal thin film, or a transparent conductive film is used. A thin film such as a thin film is removed in a line shape. When such linear removal of a thin film is performed by irradiating a laser beam, there has been a problem that the thin film is thermally damaged by heating by the laser beam as described above.

Further, in order to perform removal processing in a line shape using a laser beam, the laser beam must be scanned, and there is a problem that it takes a long time to pattern a thin film having a large area.

Further, when the laminated thin film is removed, there is another problem that the thin film serving as an underlayer is affected by the laser irradiation, resulting in poor characteristics and the like.
SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem, and to easily and efficiently remove a part of a thin film or the like in a line without causing damage such as thermal damage to the thin film. An object of the present invention is to provide a method for manufacturing a device.

[0006]

According to the present invention, there is provided a manufacturing method comprising :
Semiconductor with amorphous silicon thin film formed on metal thin film
In the manufacturing process of semiconductor devices, a small amount of amorphous silicon
Remove at least a part of the line using a reaction gas
A method for manufacturing a semiconductor device, comprising:
A metal thin film made of a material that is not processed by
Forming an amorphous silicon thin film on the metal thin film;
Amorphous silicon thin film can be selectively removed
In an atmosphere containing the reaction gas, a high-frequency voltage is applied to the plasma generating electrode having a line-shaped electric field concentration part, localized in the vicinity of the electric field concentrated portion of the plasma generating electrode, the counter <br/> response Gas Generating a linear plasma containing a plurality of radicals, and applying an amorphous silicon thin film to the linear plasma.
Processing a metal thin film by exposing the processing surface
Without removing only the amorphous silicon thin film
And a step of removing.

[0007] "Line-shaped" used in this specification
Means not only a linear shape but also a broadly defined linear shape including a curved shape, a loop shape, and the like.

[0008]

According to the present invention, a high-frequency voltage is applied to a plasma generating electrode having a line-shaped electric field concentrating portion, and a line-shaped plasma is localized and generated near the electric field concentrating portion of the plasma generating electrode.

In the present invention, the line-shaped electric field concentrating portion of the plasma generating electrode is a portion capable of causing electric field concentration when a high-frequency voltage is applied to the plasma generating electrode. And the tip of the blade electrode. Therefore, in the present invention, a plasma generating electrode having a wire electrode portion, a plasma generating electrode of a metal blade, or the like can be used.

In the present invention, the plasma is localized in the vicinity of the electric field concentrated portion to generate a linear plasma.
In order to localize and generate plasma, it is preferable to increase the atmospheric gas pressure, and it is preferable to set the atmospheric gas pressure to about 0.1 to 10 atm. If the atmospheric gas pressure is less than 0.1 atm, the plasma is not sufficiently localized, and the resolution and processing speed in patterning are reduced. When the atmospheric gas pressure exceeds 10 atm, it is necessary to considerably increase the high-frequency power to be applied, and there is a possibility that thermal damage may be caused by applying a large power. In the present invention, the atmospheric gas pressure is more preferably 1 to 3 atm.

According to the present invention, the reaction gas is contained in such an atmosphere gas.
A reactive gas is contained. This reaction gas depends on the material of the thin film.
Is selected in advance. Metal thin film and translucent conductive
For metal oxide thin films such as films, Cl-based halogen gas
Is preferred, for example, Cl _Two, BCl_Three, CCl_Fouretc
Are preferred. For semiconductor thin films, F-based
Logen gas is preferred, SF₆, CF_FourEtc. gas, also
Is preferably a gas containing hydrogen or oxygen.

Such a reaction gas is usually used by diluting it in an atmosphere gas. The concentration of the reaction gas is 0.1
~ 30% is preferred. When the concentration of the reaction gas is less than 0.1%, the efficiency of the removal processing of the thin film tends to decrease.
If the reaction gas concentration exceeds 30%, the state of the generated plasma tends to be unstable. In the present invention,
The concentration of the reaction gas is more preferably 1 to 10%.

The reaction gas is used after being diluted in the atmosphere gas as described above, and such a dilution gas can be selected in consideration of the resolution of the removal processing and the efficiency of the removal processing. Generally, an inert gas such as He, Ne, or Ar, an H ₂ gas, or the like is preferable.

In the present invention, the flow rate of the atmosphere gas containing the reaction gas is preferably 0 m / sec to the sound velocity of the atmosphere gas. For example, at 0 ° C. and 1 atm, the He gas is 97
0 m / sec, Ne gas at 435 m / sec, Ar gas at 319
The speed of sound is m / sec. If the flow rate of the atmospheric gas exceeds the speed of sound, the state of the generated plasma tends to be unstable. In the present invention, the flow rate of the atmosphere gas is more preferably 0 to 200 m / sec.

In the present invention, the high frequency power applied to one plasma generating electrode is generally set in consideration of processing efficiency, and the power per 1 cm processing length is 1 W to 50 W.
It is preferable to be within the range of 0W. Input power is 1W /
If it is less than cm, the processing efficiency may be too small. If the input power exceeds 500 W / cm, the thin film may be thermally damaged. In the present invention, the high-frequency power applied to the plasma generating electrode is more preferably in the range of 1 W / cm to 30 W / cm.

In the present invention, the frequency of the high frequency applied to the plasma generating electrode is set in consideration of processing resolution and processing efficiency, and is generally preferably in the range of 10 MHz to 3 GHz. If the frequency is less than 10 MHz, the resolution of the line removal processing may be too low. In general, it is often difficult to supply a frequency of 3 GHz or higher, and a high frequency lower than this is generally applied.

According to the present invention, in an atmosphere containing a reaction gas, a linear plasma containing a radical of the reaction gas is localized and generated in the vicinity of the electric field concentration portion of the plasma generating electrode,
By exposing a part of the surface to be processed to the linear plasma, a radical of a reaction gas reacts with the surface to be processed, and a part of the surface to be processed is removed in a line shape. According to the present invention, since the generated compound is vaporized and removed by reacting the radicals of the reaction gas with the atoms or molecules constituting the surface to be processed in this manner, damage to the surface to be processed such as thermal damage is caused. Almost without giving
Precise removal processing can be performed with high efficiency. Further, since the surface to be processed is removed by the reaction of the radical of the reaction gas, there is a material selectivity, and only a specific surface to be processed can be selectively removed.

Further, since the processing is performed by the line-shaped plasma, it is not necessary to scan the laser beam as in the conventional laser beam processing, and the processing can be performed in a short time.

[0019]

FIG. 1 is a schematic structural view for explaining a manufacturing method according to the present invention. Referring to FIG. 1, a semiconductor thin film 2 is formed on a substrate 1. Both ends of the wire electrode 3 are supported by an electrode support frame 4, and power from a high frequency power supply 5 is supplied through the electrode support frame 4. By applying the high frequency voltage, a linear plasma is generated near the wire electrode 3. By exposing the linear plasma to the semiconductor thin film 2, a linear removal portion 2a is formed in the semiconductor thin film 2.

FIG. 2 is a schematic structural view showing an apparatus for subjecting a thin film to linear plasma removal processing in accordance with the manufacturing method of the present invention. Referring to FIG. 2, an electrode support frame 4 is provided in atmosphere control chamber 9, and both ends of wire electrode 3 are supported by electrode support frame 4. A sample 6 placed on a stage 7 is arranged below the wire electrode 3. A high frequency power supply is connected to the electrode support frame 4 via a matching unit and a resonator. The atmosphere control chamber 9 is connected to a pipe from a gas supply system that supplies a reaction gas and an atmosphere gas, and is connected to a pipe to a gas exhaust system that exhausts gas in the chamber.

An atmosphere gas containing a predetermined reaction gas is supplied into the atmosphere control chamber 9 from a gas supply system, and is set to a predetermined gas pressure. In this state, when the power from the high-frequency power supply is applied to the wire electrode 3 through the electrode support frame 4, the linear plasma 8
Occurs. By applying the linear plasma 8 to a predetermined portion of the sample 6, a predetermined portion of the sample 6 is removed in a line shape.

In the present invention, it is also possible to use a plurality of wire electrodes. In order to assist the control of neutral radicals present in the linear plasma 8, photo-excitation energy is applied to the linear plasma. May be supplied. As such light excitation energy, for example, laser light can be used, and a laser light source can be provided as a light excitation energy source.

An experimental example of removing the amorphous silicon thin film in a line according to the manufacturing method of the present invention will be described below. FIG. 3 is a plan view showing a sample used for the line-shaped removal processing of the amorphous silicon thin film, and FIG.
It is sectional drawing which follows the A line. As shown in FIGS. 3 and 4,
This sample is formed on an Al metal thin film 11 on a glass substrate 10.
(Thickness 0.17 μm) and a Ti metal thin film 12 (0.08 μm thickness) formed by vapor deposition, and an amorphous silicon thin film 13 (0.58 μm thickness) formed thereon by CVD. On a part of the surface of the amorphous silicon thin film 13, an ITO film 14 made of indium tin oxide is formed. A linear plasma was applied to such a sample along the line AA shown in FIG. 3 to remove the sample linearly. The composition ratio of the atmosphere gas is He: S
F ₆ = 99: 1, the gas flow rate was 10 liter / min, and an aluminum blade (width 1 c
m, a thickness of 300 μm) and a gap between the tip of the electrode and the sample of 200 μm, a linear plasma was generated near the tip of the electrode, and a linear removal process was performed.

As a result, the removal processing was not observed in the ITO film 14, but was observed only in the amorphous silicon thin film 13. The input power was fixed at 15 W and the processing time was varied to measure the depth and width of the processed part. Table 1 shows the results.

[0025]

[Table 1]

As shown in Table 1, when the processing time is 5.0 seconds and 10.0 seconds, the processing depth is equal to the thickness of the amorphous silicon thin film and is constant, but the processing width is equal to the processing time. 1
It is wider in 0.0 seconds. This is because, after the amorphous silicon thin film is removed by the removal process, the Ti of the underlying layer is removed.
This indicates that the metal thin film is not removed by the line-shaped plasma, and that the removal is progressing only in the width direction. Therefore, the metal thin film is not processed,
Selective processing for processing only the amorphous silicon thin film has been performed.

Next, the processing time is fixed at 10.0 seconds,
By changing the input power to 15 W and 25 W, line-shaped removal processing was performed, and the depth and width of the processed portion were measured. Table 2 shows the results.

[0028]

[Table 2]

As apparent from Table 2, the input power of 15 W
In both cases of 25 W and 25 W, the depth of the processed portion matches the thickness of the amorphous silicon thin film. However, when the width of the processed portion is 25 W of applied power, the width is large. This result also indicates that the removal processing was selectively performed only on the amorphous silicon thin film, similarly to the result shown in Table 1.

Next, an embodiment for manufacturing a photovoltaic element as a semiconductor device according to the manufacturing method of the present invention will be described. Referring to FIG. 5, an insulating film 21 made of polyimide is formed on a substrate 20 made of SUS stainless steel,
An Al layer (0.17 μm thickness) and a Ti layer (0.08 μm) were sequentially laminated on the insulating film 21 to form a metal film 22.

Referring to FIG. 6, a wire electrode 30 is arranged on a predetermined portion of the metal film 22, and
, A line-shaped plasma was generated in the vicinity of and a line-shaped removal process was performed. Note that the wire electrode 30 is formed of the metal film 22.
A multi-wire electrode having a plurality of wires arranged thereon was used. As a result, a line-shaped removed portion 22a was formed in the metal film 22.

Cl ₂ was used as a reaction gas, and He was used as an atmosphere gas, and the gas composition was set to He: Cl ₂ = 95: 5. The total pressure of the atmosphere gas was 1 atm, and the flow velocity was 20 m /
Seconds. The frequency of the high frequency power supply was 144 MHz, the input power was 30 W, and the processing time was 3 seconds.

Next, referring to FIG. 7, on the metal film 22,
An amorphous silicon film 23 (0.58 μm in thickness) was formed as a photovoltaic layer having a pn junction. After the amorphous silicon thin film 23 is formed, a wire electrode 30 similar to the above is disposed on a portion where the thin film is removed, and a line-shaped plasma is generated. The portion 23a was formed.

SF ₆ was used as a reaction gas and He was used as an atmosphere gas, and the gas composition was set to He: SF ₆ = 99: 1. The total pressure of the atmosphere gas is 1 atm, and the flow velocity is 200 m
/ Sec. The frequency of the high frequency power supply was 144 MHz, the input power was 15 W, and the processing time was 5 seconds.

Next, referring to FIG. 8, an ITO film 24 (0.08 μm thick) was formed on the amorphous silicon thin film 23. After the formation of the ITO film 24, the same wire electrode 30 as described above was arranged on the portion of the ITO film 24 to be removed, and a line-shaped plasma was generated to form a line-shaped removed portion 24a on the ITO film 24. .

The reaction gas was Cl ₂ , the atmosphere gas was He, and the gas composition was He: Cl ₂ = 99: 1. The total pressure of the atmosphere gas was 1 atm, and the flow velocity was 50 m /
Seconds. The frequency of the high frequency power supply was 144 MHz, the input power was 30 W, and the processing time was 1 second.

As described above, an integrated photovoltaic device in which the ITO film and the metal electrode film of the adjacent photovoltaic device were connected was manufactured. IV of the obtained photovoltaic element
The characteristics are shown in FIG. As a comparison, a photovoltaic device in which a metal film, an amorphous silicon thin film, and an ITO film were linearly removed using a laser beam was manufactured. The characteristics are shown in FIG. The cell size of each photovoltaic element is an integrated type of 10 cm × 10 cm, light irradiation is AM-1.5, and 100 mW / cm.
The irradiation was performed at an irradiation energy of ² , and the IV characteristics were measured.

As is apparent from FIG. 9, the photovoltaic device manufactured according to the present invention has excellent photoelectric conversion characteristics as compared with the photovoltaic device obtained by the conventional line removal processing using a laser beam. ing.

Further, the patterning by the line-shaped plasma in the present invention is not limited to the patterning of the above-described embodiment, but may be employed, for example, in the manufacture of a photoelectric conversion element mounted on a micromachine or the like.
FIG. 10 to FIG. 13 are diagrams showing a manufacturing process of such a micromachine photoelectric conversion element.

Referring to FIG. 10, on a flexible substrate 30, a photovoltaic substrate 31 on which a photovoltaic element is formed is formed. For the photovoltaic substrate 31, nine radial line-shaped removal processing portions 32, an arc-shaped removal processing portion 34 connecting one end of the line-shaped removal processing portion 32, and the other end of the line-shaped removal processing portion 32. An arc-shaped line-shaped removal processing portion 33 to be connected is formed. Thus, eight photovoltaic element units 35 are formed. After forming the line-shaped removal processing portion of such a predetermined pattern on the photovoltaic substrate 31, it is taken out together with the flexible substrate 30, and as shown in FIG. By bonding
It is formed in a conical shape as shown in FIG. In the state shown in FIG. 12, a predetermined wiring connection is made to each photovoltaic element unit 35 to form a photoelectric conversion element for mounting a micromachine.

The photoelectric conversion element 36 thus formed
Is mounted on a micromachine 37 as shown in FIG. Such a micromachine 37 is, for example, as shown in FIG.
As shown in the figure, the robot can be put in the tube 38 and run by itself. In such a case, a driving device capable of moving on the inner wall of the tube 38 is attached to the micromachine 37, and when light is applied to the photoelectric conversion element 36, electric power is generated in the photoelectric conversion element 36. Then, the micromachine 37 moves in the tube 38 using this electric power.

In the above embodiments, the manufacturing method of the present invention has been described by exemplifying a photovoltaic element as a semiconductor device. However, the semiconductor device manufactured by the manufacturing method of the present invention is not limited to a photovoltaic device. However, the present invention can be applied to the manufacture of other semiconductor devices as long as the semiconductor device requires a step of removing a part of the surface in a line shape. For example, as described above, the present invention can be applied to a case where at least a part of the surface of a semiconductor wafer such as a silicon wafer is removed in a line shape.

[0043]

According to the present invention, a localized linear plasma is generated in the vicinity of the electric field concentrated portion of the plasma generating electrode, and the radical of the reactive gas in the linear plasma reacts with the thin film to form a thin film. A part of the processed surface is removed in a line shape. Therefore, unlike the conventional removal processing by laser beam irradiation, the surface to be processed is not damaged such as thermal damage.

Since the reaction gas reacts with radicals, by selecting the reaction gas according to the material of the surface to be processed, for example, a selective line is formed so that the underlying layer is not subjected to removal processing. Shape removal processing can be performed.

In the present invention, since the line-shaped removal processing is performed by the line-shaped plasma, it is not necessary to scan the laser beam light as in the conventional laser beam, and the removal processing can be performed in a short time. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram for explaining a process of removing a thin film by linear plasma in a manufacturing method of the present invention.

FIG. 2 is a schematic configuration diagram showing an example of an apparatus that can be used to carry out the manufacturing method of the present invention.

FIG. 3 is a plan view showing a sample to be removed in an embodiment of the present invention.

FIG. 4 is a sectional view taken along the line AA in FIG. 3;

FIG. 5 shows a manufacturing process of an embodiment according to the present invention,
Sectional drawing which shows the state after forming a metal film.

FIG. 6 shows a manufacturing process of an embodiment according to the present invention,
Sectional drawing which shows the state after performing linear removal processing to a metal film.

FIG. 7 shows a manufacturing process of an embodiment according to the present invention,
Sectional drawing which shows the state after performing the line-shaped removal process to the amorphous silicon thin film.

FIG. 8 shows a manufacturing method of an embodiment according to the present invention,
Sectional drawing which shows the state after performing linear removal processing to the ITO film.

FIG. 9 is a diagram showing IV characteristics of a photovoltaic device manufactured in an example of the present invention.

FIG. 10 is a perspective view showing a step of manufacturing a photoelectric conversion element for a micromachine which can be manufactured according to the present invention, and showing a state after a line-shaped removal processing portion is formed on a photovoltaic substrate.

FIG. 11 is a perspective view showing a state in which a removal processing portion is formed on the photovoltaic substrate and then taken out and the flexible substrate is bent as shown in FIG.

12 is a perspective view showing a state in which a flexible substrate is bent to form a conical micromachined photoelectric conversion element portion as shown in FIG. 11;

13 is a configuration diagram showing a state where the photoelectric conversion element unit of the micromachine shown in FIG. 12 is attached to the micromachine and arranged inside a tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Semiconductor thin film 2a ... Semiconductor thin film linear removal processing part 3 ... Wire electrode 4 ... Electrode support frame 5 ... High frequency power supply 8 ... Linear plasma 9 ... Atmosphere control chamber 10 ... Glass substrate 11 ... Al metal thin film 12 ... Ti metal thin film 13 ... Amorphous silicon thin film 14 ... ITO film 20 ... Substrate 21 ... Insulating film 22 ... Metal film 22a ... Linear removal processing part of metal film 23 ... Amorphous silicon thin film 23a ... Amorphous silicon thin film 24: ITO film 24a: ITO film linear removal processing part 30: Wire electrode

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Wataru Shinohara 2--18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Yoichi Domoto 2-18-3 Keihanhondori, Moriguchi-shi, Osaka Examiner, Yoichi Electric Co., Ltd. Junichi Imai (56) References JP-A-5-47709 (JP, A) JP-A-4-128393 (JP, A) JP-A-6-85059 (JP, A) JP 4-246184 (JP, A) JP-A-5-234942 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/3065 B23H 1/06 C23F 4/00

Claims (1)

(57) [Claims] Amorphous silicon formed on a metal thin film
In the manufacturing process of a semiconductor device having a thin film,
A method for manufacturing a semiconductor device in which at least a part of a porous silicon thin film is removed and processed in a line shape using a reaction gas, wherein the substrate is made of a material that cannot be processed by the reaction gas.
A metal thin film is formed, and an amorphous silicon thin film is formed on the metal thin film.
Forming a film and selectively removing the amorphous silicon thin film.
In an atmosphere containing the reaction gas, a high-frequency voltage is applied to a plasma generating electrode having a linear electric field concentrating portion, and the high frequency voltage is localized near the electric field concentrating portion of the plasma generating electrode.
Generating a linear plasma containing radicals of the reactive gas; and applying the amorphous silicon thin film to the linear plasma.
The metal thin film can be processed by exposing
And selectively line only the amorphous silicon thin film.
A semiconductor device manufacturing method, comprising: