JP3261795B2 - Plasma processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the manufacture of devices using semiconductors such as thin film transistors and various sensors utilizing semiconductors, solar cells, and the like. Plasma CVD for etching the formed film according to a predetermined pattern
And a plasma processing apparatus such as a plasma etching apparatus.

[0002]

2. Description of the Related Art Various types of plasma CVD apparatuses are known. As a representative example, a parallel plate type plasma CVD apparatus shown in FIG. 3 will be described. This apparatus has a vacuum vessel 1 in which an electrode 2 also serving as a substrate holder for installing a film-forming substrate S1 and an electrode 2 Are provided.

[0003] The electrode 2 is usually a ground electrode.
A heater 21 for heating the substrate S1 mounted thereon to a film forming temperature is additionally provided. The heater 21 may be separately arranged to heat the substrate S1 by radiant heat. The electrode 3 is a power application electrode for applying high-frequency power or DC power to the film-forming gas introduced between the electrode 3 and the plasma to generate plasma, and in the illustrated example, a high-frequency power source 32 through a matching box 31. Is connected.

In the illustrated example, the electrode 3 is provided with a porous electrode plate 34 at an opening of a gas nozzle 33 constituting a part of the electrode.
In the electrode plate 34, a number of gas supply holes having a diameter of about 0.5 mm are formed, so that the gas supplied from the gas nozzle 33 is discharged from each hole between the electrodes as a whole. It is. Such a configuration is suitable for forming a film on a wide-area substrate.

[0005] Further, a ground electrode 40 for preventing the sneak of plasma is provided so as to surround the peripheral portion of the high-frequency electrode 3 and the entire back surface which is continuous with the high-frequency electrode 3 at a constant distance from the electrode. An exhaust pump 52 is connected to the vacuum vessel 1 via an on-off valve 51 via a pipe, and a gas supply unit 4 is connected to the gas nozzle 33 via a pipe. One or more mass flow controllers 421, 422,... And on-off valves 431, 432,.
Are supplied through a plurality of gas sources 441, 442,.

According to this parallel plate type plasma CVD apparatus, the substrate S1 to be formed is placed on the electrode 2 in the vacuum vessel 1, and the inside of the vessel 1 is formed by opening the valve 51 and operating the exhaust pump 52. The film is maintained at a degree of vacuum, and a film forming gas is introduced from the gas supply unit 4 through the gas supply holes of the nozzle 33 and the electrode plate 34. Further, a high-frequency voltage is applied to the high-frequency electrode 3 from the power supply 32, and the introduced gas is turned into plasma, and a desired film is formed on the surface of the substrate S1 under this plasma.

[0007] Various types of plasma etching apparatuses are also known. A parallel plate type etching apparatus shown in FIG. 4 will be described as a typical example. This apparatus also includes a vacuum vessel 10, in which an electrode 20 also serving as a substrate holder for installing a substrate S2 on which a film to be etched is formed, and An electrode 30 is provided opposite to the electrode 20.

The electrode 20 is used as a power application electrode for applying a high frequency power or a DC power to the etching gas introduced between the electrode 30 and the plasma to form a plasma. Connected to the high frequency power supply 202. Further, a ground electrode 60 for preventing the plasma from flowing around is provided at a certain interval from the high frequency electrode 20 so as to surround the peripheral portion of the high frequency electrode 20 and the entire back surface connected thereto.

The electrode 30 is a ground electrode, and a porous electrode plate 302 is provided at an opening of a gas nozzle 301 constituting a part of the electrode.
The electrode plate 302 is provided with a large number of gas supply holes having a diameter of about 0.5 mm. The gas supplied from the gas nozzle 301 is discharged from the holes between the electrodes as a whole. Has become. An exhaust pump 72 is further connected to the vacuum vessel 10 via an on-off valve 71, and a gas supply unit 6 is connected to the gas nozzle 301. The gas supply unit 6 supplies a required amount of etching gas through one or more mass flow controllers 621, 622,... And on-off valves 631, 632,. ··It is included.

According to this etching apparatus, the substrate S2 to be etched is placed on the high-frequency electrode 20 in the container 10, and the inside of the container 10 is maintained at a predetermined etching vacuum degree by opening the valve 71 and operating the exhaust pump 72. , Gas supply unit 6
From the nozzle 301 and the electrode plate 302
The gas is introduced through the gas supply holes. Further, a high-frequency voltage is applied to the electrode 20 from the high-frequency power supply 202, and the introduced gas is turned into plasma, and the film on the substrate S2 is etched under the plasma. The electrode 20
May be cooled by the water cooling device 200 or the like as necessary.

[0011]

However, in such a plasma processing apparatus, fine particles generated by a gas phase reaction in plasma adhere to a film formed on the substrate surface or mix into the film. There is a problem that the film quality is deteriorated, and there is a problem that the generated fine particles adhere to and contaminate each part in the vacuum vessel. Fine particles adhering to various parts in the vacuum vessel may eventually peel off and adhere to the substrate to be processed.

In particular, fine particles are formed by a gas phase reaction,
It is highly likely that the film will grow greatly, for example, an amorphous silicon (a-Si) film made of silane (SiH ₄ ) and hydrogen (H ₂ ), and an amorphous silicon nitride (a) made of silane and ammonia (NH ₃ ). In the case where an amorphous silicon oxide (a-SiO ₂ ) film is formed from silane and dinitrogen monoxide (nitrous oxide) (N ₂ O), a film formed on the surface of the substrate is used. When the size of the fine particles adhering to or mixed into the film is larger than the thickness of the film to be formed, as a result, when the film is an insulating film, when the cleaning process is performed after the film formation, the fine particle portion is removed. If the film becomes a pinhole and insulation failure occurs, or if the film is a semiconductor film, there is a problem that the semiconductor characteristics are deteriorated.

Also, in the plasma etching apparatus, similarly, there is a problem that fine particles are formed by a gas phase reaction and adhere to a surface to be etched or to various parts in a vacuum vessel. For example, in the case where a wiring pattern is formed by etching, such fine particles cause deterioration in patterning accuracy, and may cause disconnection in the formation of fine lines.

Accordingly, the present invention provides a plasma processing apparatus capable of efficiently removing fine particles generated by a gas phase reaction in plasma and suppressing the fine particles from adhering to a substrate to be processed or various parts in a vacuum vessel. The task is to The term “adhesion” referred to here and “adhesion” to be described later in the “effect of the invention” means not only adhesion to various parts in a vacuum vessel, but also direct deposition to a substrate surface in film formation. In the case of etching, it refers to direct adhesion to the surface of a substrate, adhesion to and contamination of a film to be etched, and the like.

[0015]

According to the present invention, there is provided a plasma processing apparatus comprising: an electrode for applying power for generating plasma; An opposing electrode is provided, a ground electrode is provided to prevent a plasma sneak around the peripheral portion and the back surface of the electrode while maintaining a constant gap with respect to the power application electrode, and the power application electrode and an electrode opposed thereto are provided. In a plasma processing apparatus which applies a power to the power application electrode to generate a plasma by applying a power to the power application electrode, and performs a target plasma process on a substrate to be processed under the plasma , Electrodes have no gas passage holes
Alternatively, only the processing gas supply holes are provided as gas passage holes.
And a means for exhausting gas from the gap between the power application electrode and the ground electrode surrounding the power application electrode.

The means for evacuating from the gap between the power application electrode and the ground electrode surrounding the power application electrode may use the above-described evacuation device for maintaining the inside of the vacuum vessel at a predetermined processing vacuum. May be prepared separately. Also,
It is desirable that the evacuation means be capable of uniformly exhausting the entirety of the gap as much as possible in order to remove the fine particles from the entirety of the plasma generation region adjacent to the power application electrode as much as possible. It is desirable to be connected to the gap on the back side, and it is particularly desirable to be connected to the gap at a position corresponding to the center of the back of the electrode.

[0017]

According to the plasma processing apparatus of the present invention, during plasma processing, fine particles generated near the power application electrode and concentrated at the periphery of the electrode form a gap between the power application electrode and a ground electrode surrounding the electrode. Is exhausted by the exhaust means, thereby being sucked into the gap and discharged out of the plasma region.
Therefore, the adhesion of the fine particles to the substrate to be processed and each part in the vacuum vessel is suppressed accordingly.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a plasma CVD apparatus according to an embodiment of the present invention. FIG. 2 shows a plasma etching apparatus according to an embodiment of the present invention. The plasma CVD apparatus shown in FIG. 1 is different from the conventional apparatus shown in FIG. 3 in that a gap A between a high-frequency electrode 3 and a ground electrode 40 surrounding the high-frequency electrode 3 for preventing plasma wraparound.
In contrast, the exhaust device 8 is connected at a position corresponding to the center of the back surface of the electrode 3. The exhaust device 8 is an exhaust adjustment valve 8
1 and an exhaust pump 82. The configuration is the same as that of the apparatus in FIG. 3 except that the exhaust device 8 is adopted, and the entire film forming operation is also the same. Components that are the same as those in the apparatus of FIG. 3 are given the same reference numerals.

According to this plasma CVD apparatus, the substrate S1 to be formed is set on the electrode 2, and thereafter, a target film is formed on the surface of the substrate in the same procedure as described for the apparatus in FIG. However, in this apparatus, the gap A between the high-frequency electrode 3 and the ground electrode 40 surrounding the high-frequency electrode 3 is formed during the film formation.
Exhausted by Therefore, during the film formation, the fine particles generated by the gas phase reaction in the plasma, particularly the fine particles generated near the high-frequency electrode 3 and concentrated at the periphery of the electrode, are efficiently sucked into the gap A and discharged out of the plasma region. You.

Therefore, the substrate S1 to be processed and the vacuum vessel 1
The adhesion of fine particles to each part in the inside is suppressed accordingly, the defects of the formed film are greatly reduced, and the number of maintenance operations such as fine particle removal cleaning of each part in the vacuum vessel can be reduced compared to the conventional, high throughput Is achieved. An example in which an a-Si: H film is formed by the above-described apparatus of FIG. 1 will be described.

Deposition conditions Substrate: 5 inch silicon wafer Gas: SiH ₄ 100 sccm H ₂ 400 sccm Deposition temperature: 230 ° C. Deposition gas pressure: 0.4 Torr Applied power: 200 W Electrode size: 360 mm × 360 mm □ Electrode interval: 45 mm ( (Distance between the electrode and the surface of the substrate S1) In this film formation, the number of attached fine particles in the formed a-Si: H film was 0.3 μm or more, and was 5 or less.

According to the conventional apparatus shown in FIG. 3, the number of adhered fine particles was about 50 under the same film forming conditions except that the gas was not exhausted from the gap A. Next, the plasma etching apparatus shown in FIG. 2 is different from the conventional apparatus shown in FIG.
The exhaust device 9 is connected at a position corresponding to the central portion of the back surface of the electrode 20 with respect to the gap B between 0 and 0. The exhaust device 9 includes an exhaust adjusting valve 91 and an exhaust pump 92. The configuration is the same as that of the apparatus in FIG. 4 except that the exhaust device 9 is adopted, and the entire etching operation is also the same. Parts that are the same as the parts in the apparatus of FIG. 4 are given the same reference numerals.

According to this plasma etching apparatus, the substrate S2 to be etched is set on the electrode 20, and thereafter,
Etching is performed in the same procedure as described for the apparatus of FIG. However, in this apparatus, the gap B between the high-frequency electrode 20 and the ground electrode 60 surrounding the high-frequency electrode 20 is exhausted by the exhaust device 9 during etching. Therefore, during etching, fine particles generated by a gas phase reaction in plasma,
Further, the fine particles generated near the substrate S2 and concentrated on the periphery of the electrode are efficiently sucked into the gap B and discharged out of the plasma region.

Therefore, the substrate S2 to be processed and the vacuum vessel 1
The adhesion of the fine particles to each part in the inside is suppressed accordingly, the etching failure is greatly reduced, and the number of maintenances such as the fine particle removal cleaning of each part in the vacuum vessel can be reduced as compared with the conventional case, thereby achieving a high throughput. You.

[0025]

As described above, according to the present invention, it is possible to efficiently remove fine particles generated by a gas phase reaction in plasma, and to suppress the fine particles from adhering to a substrate to be processed or various parts in a vacuum vessel. And a plasma processing apparatus capable of performing the above.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a plasma CVD apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a plasma etching apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of an example of a conventional plasma CVD apparatus.

FIG. 4 is a schematic configuration diagram of an example of a conventional plasma etching apparatus.

[Explanation of symbols]

 1, 10 Vacuum container 2, 30 Ground electrode 20, 3 High frequency electrode 201, 31 Matching box 202, 32 High frequency power supply 21 Heater 51, 71 Open / close valve 52, 72 Exhaust pump 4, 6 Gas supply unit 8, 9 Exhaust device 81, 91 Displacement adjusting valve 82, 92 Exhaust pump A Gap between electrode 3 and electrode 40 B Gap between electrode 20 and electrode 60 S1 Film formation target substrate S2 Etching target substrate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-93924 (JP, A) JP-A-59-43880 (JP, A) JP-A-1-137621 (JP, A) JP-A-3-93 107481 (JP, A) Japanese Utility Model 1-100432 (JP, U) Japanese Utility Model 2 132937 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/205 C23C 16 / 50 H01L 21/3065

Claims (1)

(57) [Claims] An electrode for applying power for plasma generation and an electrode facing the electrode are provided in a vacuum vessel that can be maintained in a predetermined processing vacuum state by an exhaust device, and a predetermined gap is provided between the electrode for applying power and the electrode. A ground electrode for preventing the plasma from wrapping around the periphery and the back surface of the electrode is provided, and the processing gas introduced between the power application electrode and the electrode facing the power application electrode supplies power to the power application electrode. applied to by plasma, in the plasma processing apparatus which performs plasma processing for the purpose processed substrate under the plasma, wherein
The electrode for applying power can be an electrode without gas passage holes or a gas passage.
An electrode having only a supply hole for the processing gas as a perforation;
And a means for exhausting gas from a gap between the power application electrode and the ground electrode surrounding the power application electrode.