KR101349266B1 - Plasma processing apparatus and method of forming micro crystal silicon layer - Google Patents

Abstract

This plasma processing apparatus includes a processing chamber composed of a chamber 2, an electrode flange 4, and an insulating flange 81, and having a reaction chamber α; A support part 15 accommodated in the reaction chamber and on which the substrate 10 is placed; A shower plate (5) accommodated in the reaction chamber (alpha), disposed to face the substrate (10), and supplying a process gas toward the substrate (10); It is installed in the space 31 between the electrode flange 4 and the shower plate 5, and is concentrically and annularly arranged in communication with each of the plurality of gas inlets 34, and to the shower plate 5 A plurality of gas supply parts 8 for independently supplying the process gases of different compositions toward the fuel cell; And a voltage applying unit 33 for applying a voltage between the shower plate 5 and the support unit 15.

Description

Plasma processing apparatus and method of forming micro crystal silicon layer

The present invention relates to a plasma processing apparatus.

This application claims priority based on Japanese Patent Application No. 2009-004023 for which it applied on January 9, 2009, and uses the content here.

DESCRIPTION OF RELATED ART Conventionally, the film-forming apparatus (p-CVD film-forming apparatus) by the plasma CVD method which forms a thin film on a board | substrate using the process gas of a plasma state as an example of a plasma process is known. This p-CVD film forming apparatus is used, for example, when forming an amorphous silicon (a-Si) film on a substrate.

6 is a schematic cross-sectional view showing an example of a conventional p-CVD film deposition apparatus.

In FIG. 6, the film forming apparatus 101 has a chamber 102, and a strut 125 that is capable of lifting up and down by inserting a bottom surface of the chamber 102 into the lower portion of the chamber 102 is disposed. It is. The plate-shaped base plate 103 is attached to the end of the strut 125 in the chamber 102. The electrode flange 104 is attached to the upper part of the chamber 102 via the insulating flange 181.

Between the chamber 102 and the electrode flange 104, a shower plate 105 is mounted to the electrode flange 104. A space 131 is formed between the shower plate 105 and the electrode flange 104.

The gas introduction pipe 107 is connected to the electrode flange 104. The process gas is supplied into the space 131 from the deposition gas supply part 121 through the gas introduction pipe 107. The shower plate 103 is provided with a plurality of gas blowing holes 106. Process gas supplied into the space 131 is ejected from the gas outlet 106 into the chamber 102.

In addition, when a film is formed on the substrate 115 which is the object to be processed, a film forming material adheres to the inner wall surface of the chamber 102 or the like. In order to remove such a film forming material, the film forming apparatus 101 has a radical source 123 connected to the chamber 102 and a fluorine gas supply part 122 connected to the radical source 123. The fluorine gas supplied from the fluorine gas supply unit 122 is decomposed at the radical source 123 to obtain fluorine radicals, and the deposits (deposition materials) are removed by supplying the fluorine radicals to the film formation space in the chamber 102.

The surface of the base plate 103 is formed flat. The support 110 is placed on the upper surface of the base plate 103. The amount of deformation of the support 110 is suppressed by placing the support 110 on the base plate 103 in this way.

In addition, the surface of the support part 110 is formed flat like the base plate 103. The substrate 115 is placed on the upper surface of the support 110.

When the substrate 115 is disposed, the substrate 115 and the shower plate 105 are approximately parallel to each other in close proximity.

When the process gas is ejected from the gas ejection port 106 with the substrate 115 disposed on the support 110, the process gas is supplied onto the surface of the substrate 115.

The electrode flange 104 and the shower plate 105 are made of a conductive material. The electrode flange 104 is connected to an RF power source 133 (high frequency power source) provided outside the chamber 102.

In order to form a thin film on the surface of the substrate 115 using the film forming apparatus 101 having the above configuration, first, the vacuum pump 128 is used to reduce the pressure inside the chamber 102.

The substrate 115 is loaded into the vacuum chamber 102 and placed on the support 110 with the chamber 102 maintained in a vacuum state.

Thereafter, the process gas is supplied through the gas introduction pipe 107, and the process gas is ejected from the gas ejection port 106 into the vacuum chamber 102.

The electrode flange 104 is electrically insulated from the chamber 102 via the insulating flange 181. The high frequency power supply 133 (for example, an RF power supply) is started in the state in which the chamber 102 is grounded, and a high frequency voltage is applied to the electrode flange 104. As a result, a high frequency voltage is applied between the shower plate 105 and the support 110 to generate a discharge, and plasma P of the process gas is generated between the shower plate 105 and the surface of the substrate 115. The process gas is decomposed in the plasma P generated as described above, and a gas phase growth reaction occurs on the surface of the substrate 115 to form a thin film on the surface of the substrate 115.

In addition, since the film forming material adheres to the inner wall surface of the chamber 102 and the like after the film forming process is repeated many times, the inside of the chamber 102 is periodically cleaned. In the cleaning process, the fluorine gas supplied from the fluorine gas supply unit 122 is decomposed by the radical source 123 to generate fluorine radicals, and the fluorine radicals are supplied into the chamber 102. By supplying fluorine radicals to the film formation space in the chamber 102 in this manner, a chemical reaction occurs, and deposits attached to the inner wall surface of the chamber 102 and the like are removed.

By the way, compared with the conventional liquid crystal display (LCD) manufacture, solar cell manufacture, especially the manufacture of the solar cell using microcrystal silicon (microc-Si), requires the speed-up of the film-forming speed from a viewpoint of productivity.

As deposition conditions, for example, a high pressure process in which hydrogen (H ₂ ) is diluted at a relatively high magnification with respect to monosilane (SiH ₄ ) is generally used. As such a high speed film-forming method, the high pressure depletion method by a narrow gap is used effectively (for example, refer patent document 1 and patent document 2).

In addition, in the film formation method of microcrystal silicon, hydrogen radicals affect the film quality of microcrystal silicon. When the amount of hydrogen radicals is large, the silicon film is likely to crystallize. In addition, when the amount of hydrogen radicals is small, an amorphous film is easily obtained.

In the manufacture of the above-mentioned solar cell, the solar cell is often produced using the board | substrate which has the magnitude | size more than about G5 size (1100 mm x 1300 mm) in LCD manufacture in recent years.

In an actual production apparatus, gas inlets are provided at one or a plurality of locations on the electrode flange, and a mixed gas (process gas) of monosilane and hydrogen is supplied into the space 131. Moreover, the discharge rate of process gas is made uniform by a shower plate, this process gas is discharged to the film-forming space, the process gas is decomposed | disassembled by the generated plasma, and the film | membrane is formed on the board | substrate (for example, patent document 3). Reference).

In the actual plasma processing apparatus, the gas in the processing space is exhausted through an exhaust port formed at the periphery of the susceptor (support). Therefore, even if the mixed gas containing monosilane and hydrogen in the same ratio is uniformly supplied (released) in the processing space, hydrogen radicals are generated by decomposing the monosilane gas by the plasma reaction, so that the hydrogen radicals are generated from the outside of the substrate 115. there is a hydrogen radical (H ^{* 1)} and the monosilane gas is decomposed generated hydrogen radicals (H ^{2 *)} are (to be increased), the amount of hydrogen radicals (H ^*), combined with each other problems arising from the increasing hydrogen gas.

That is, by exhausting a gas containing radicals present in the processing space, a flow is generated toward the periphery of the susceptor, i.e., the support, and thus the amount of hydrogen radicals H ^* varies depending on the position in the processing space. .

Such a state is shown schematically, for example, as shown in FIG.

7 shows the amount (concentration) of hydrogen radicals contained in the processing space (film formation space) and the position (measurement point) in the processing space when the process gas is supplied (released) and reacted using a conventional plasma processing apparatus. It is a schematic diagram showing a relationship.

In FIG. 7, the concentration of the hydrogen radical (H ^{* 1} ) generated from the hydrogen gas is shown by the dashed-dotted line, the concentration of the hydrogen radical (H ^{* 2} ) produced by the decomposition of the monosilane gas is shown by the ^double- dotted line, and the hydrogen radical (H ^*). The amount of hydrogen radicals H ^* combined with ¹ and H ^{* 2} ) are shown in solid lines.

As shown in Fig. 7, in the plasma processing apparatus having the conventional structure, even if the shower plate is adjusted so that the process gas mixed with monosilane and hydrogen is uniformly discharged into the film formation space, the hydrogen radicals (H ^* A difference occurs in the quantity of). In the region from the central portion (center portion of the deposition space) to the peripheral edge portion of the substrate 115, it was difficult to uniformly perform plasma treatment on the substrate 115.

Therefore, there is a problem that it is difficult to obtain in-plane uniformity of the film quality formed on the substrate 115.

Moreover, in the said patent document 1 and patent document 2, high speed film forming is implement | achieved by supplying (releasing) a process gas uniformly, but the quantity of the hydrogen radical generated by reaction of the process gas supplied (released) to the film-forming space is considered. It is not.

Moreover, although the uniformity of the film thickness of the deposited film deposited on the board | substrate improves in the said patent document 3, the quantity of the hydrogen radical (H ^* ) which exists in each of several position in a process space is not considered.

Therefore, in Patent Documents 1 to 3, the amount of hydrogen radicals H ^* cannot be uniformly adjusted according to the position in the processing space, and the plasma processing is performed on the substrate 115 in the region from the center portion to the peripheral portion of the substrate 115. Cannot be performed uniformly.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-280377 Patent Document 2: Japanese Patent Application Laid-Open No. 2004-296526 Patent Document 3: Japanese Patent Application Laid-Open No. 2006-13799

This invention is made in view of the above-mentioned situation, and an object of this invention is to provide the plasma processing apparatus which can perform a plasma processing to a board | substrate uniformly in the area | region from the center part to the periphery part of a board | substrate to which a plasma process is performed.

In order to solve the above problems, the plasma processing apparatus of the present invention comprises a chamber, an electrode flange having a plurality of gas inlets, a processing chamber having an reaction flange interposed by the chamber and the electrode flange; A support part accommodated in the reaction chamber, a substrate is placed, and controlling a temperature of the substrate; A shower plate accommodated in the reaction chamber, disposed to face the substrate, and supplying a process gas toward the substrate; It is provided in the space between the electrode flange and the shower plate, and arranged in concentric and annular communication with each of the plurality of gas inlet port, a plurality of independent supply of the process gas of different composition toward the shower plate Gas supply unit; And a voltage applying unit configured to apply a voltage between the shower plate and the support unit.

In this structure, the some gas supply port is provided in the gas supply part. In addition, a plurality of second gas ejection ports are provided in the shower plate. The gas supply portion also includes an annular portion arranged concentrically. In addition, the shower plate functions as the first electrode portion. The support portion also functions as the second electrode portion. The process gas supplied through the second gas jet port toward the substrate is in a plasma state by the voltage supplied by the voltage applying unit.

It is preferable that the plasma processing apparatus of this invention is a film-forming apparatus.

It is preferable that the plasma processing apparatus of this invention is an etching apparatus.

In the plasma processing apparatus of the present invention, the gas supply unit preferably supplies the process gas onto the substrate so that the concentration of hydrogen supplied to the peripheral portion of the substrate is lower than the concentration of hydrogen supplied to the central portion of the substrate.

In the plasma processing apparatus of the present invention, a plurality of gas supply units that independently supply process gases of different compositions or types toward the shower plate are provided, and a plurality of first gas ejection ports are arranged in the gas supply unit. According to this configuration, in consideration of the amount of hydrogen radicals generated by the reaction of the process gas at predetermined positions in the region from the center portion to the peripheral portion of the processing surface (surface) of the substrate, the hydrogen concentration of the process gas for each gas supply portion before the plasma treatment is performed. You can adjust the ratio. Therefore, it is possible to supply (release) the process gas in which the ratio of the mixed gas or the concentration of each gas is nonuniform.

In addition, a plurality of second gas ejection openings are arranged in the shower plate, and the process gas is supplied to the substrate through the second gas ejection opening. In addition, the voltage applying unit applies a high frequency voltage between the first electrode portion made of the shower plate and the second electrode portion made of the support portion. Thereby, the process gas in which the ratio of the mixed gas or the density | concentration of each gas is nonuniform is supplied (released) in space through the 1st gas blowing port of a gas supply part. This process gas is uniformly supplied to the reaction space in which the substrate is disposed through the second gas outlet of the shower plate. As a result, a process gas in a plasma state is obtained.

For example, when a mixed gas consisting of a monosilane (SiH ₄ ) gas and a hydrogen (H ₂ ) gas is used as the process gas, hydrogen contained in the process gas at predetermined positions in the region from the center portion to the peripheral portion of the processing surface of the substrate is used. The mixing ratio of the gas and the monosilane gas is changed. Accordingly, to control the total amount of the hydrogen radicals (H ^{* 1)} and monosilane hydrogen radicals generated gas is decomposed (H ^{* 2)} hydrogen radicals are combined with each other (H ^*) generated from the hydrogen gas to be equal at the predetermined position respectively, It becomes possible. In other words, the hydrogen radicals can be uniformly exposed to the processing surface regardless of the position on the processing surface in the region from the central portion to the peripheral edge of the processing surface of the substrate.

According to this invention, the plasma processing apparatus which can perform a plasma process uniformly on the whole surface of the process surface of a board | substrate is obtained.

For example, when a mixed gas containing hydrogen gas and monosilane gas is used as the process gas as described above, the thickness of the silicon film formed on the entire surface of the processing surface can be made uniform, and the film quality is uniform. For example, an a-Si film or a microcrystalline Si film or the like can be formed.

In addition, when the mixed gas which etches the film formed on the process surface of a board | substrate as a process gas is used, the whole surface of the film on a process surface can be etched uniformly at a desired etching rate. In addition, when the resist pattern which has an opening part is formed on the film | membrane formed on the process surface, the film formed on the process surface can be etched according to the shape of an opening part.

In addition, productivity does not fall in the process of processing an electrode flange, and the mechanical strength of an electrode flange does not fall with the increase of the number of gas introduction ports. Moreover, the number of gas supply systems does not increase, and manufacturing cost does not increase.

1 is a schematic cross-sectional view showing the configuration of a plasma processing apparatus according to the present invention.
2 is a schematic plan view showing an example of a structure of a gas supply unit of the plasma processing apparatus according to the present invention.
3 is a schematic plan view showing an example of a structure of a gas supply unit of the plasma processing apparatus according to the present invention.
4 is a schematic diagram showing a plurality of measurement points on a processing surface of a substrate measured by Raman spectroscopy.
5 is a schematic diagram showing the relationship between the amount (concentration) and the position of hydrogen radicals present in the process gas in the plasma state in the film formation space of the plasma processing apparatus according to the present invention.
6 is a schematic view showing the configuration of a conventional plasma processing apparatus.
7 is a schematic diagram showing the relationship between the amount (concentration) and the position of hydrogen radicals present in the process gas in the plasma state in the film formation space of the conventional plasma processing apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the plasma processing apparatus which concerns on this invention is described based on drawing.

In addition, in each drawing used for the following description, since each component is made into the magnitude | size which can be recognized on drawing, the dimension and ratio of each component are changed suitably from an actual thing.

In addition, in this embodiment, the case where a plasma processing apparatus is a film-forming apparatus is demonstrated.

1 is a schematic view showing the configuration of a film forming apparatus in this embodiment.

As shown in FIG. 1, the film-forming apparatus 1 (p-CVD film-forming apparatus) by the plasma CVD method is equipped with the process chamber which has reaction chamber (alpha). The process chamber is composed of an insulating flange 81 interposed between the chamber 2, the electrode flange 4, the chamber 2, and the electrode flange 4. That is, the electrode flange 4 is attached to the upper part of the chamber 2 via the insulating flange 81. Therefore, the electrode flange 4 is electrically insulated from the chamber 2 via the insulating flange 81.

On the other hand, the opening part is formed in the bottom part 11 of the chamber 2. The strut 25 is inserted through the opening, and the strut 25 is disposed below the chamber 2. An end of the strut 25 located in the chamber 2 is connected to the bottom surface 19 of the plate-shaped base plate 3.

Moreover, the film-forming apparatus 1 is equipped with the support part 15 accommodated in the reaction chamber (alpha) and on which the board | substrate 10 which is a to-be-processed object is placed. This support part 15 is arrange | positioned below the reaction chamber (alpha).

One end of the exhaust pipe 28 is connected to the chamber 2. The other end of the exhaust pipe 28 is provided with a vacuum pump 27. When the vacuum pump 27 is started, the vacuum pump 27 exhausts the gas and the reaction product present in the chamber 2 through the exhaust pipe 28, and depressurizes the inside of the chamber 2 to a vacuum state. Therefore, reaction chamber (alpha) comprises an airtight vacuum processing chamber. In addition, the chamber 2 is electrically grounded, and the potential of the chamber 2 is maintained at the ground potential. Here, the ground potential means that the potential of the chamber 2 is in a ground potential state or an earth state.

The base plate 3 is a plate-shaped member having a flat surface. The support part 15 is placed on the upper surface of the base plate 3. The base plate 3 is made of nickel-based alloys such as Inconel®. The base plate 3 may be formed of another material as long as it is a material having rigidity and having corrosion resistance and heat resistance.

Moreover, the support | pillar 25 is connected to the lifting mechanism (not shown) provided in the exterior of the chamber 2, and can move up and down in the perpendicular direction of the board | substrate 10. As shown in FIG. That is, the base member 3 and the support part 15 arrange | positioned on the base member 3 connected to the edge part of the support | pillar 25 can be elevated up and down. Moreover, the bellows 26 is provided in the exterior of the chamber 2 so that the outer periphery of the support | pillar 25 may be covered.

The shower plate 5 is attached to the chamber 2 side of the electrode flange 4 so as to form the space 31. The shower plate 5 is accommodated in the reaction chamber α and is disposed to face the processing surface of the substrate 10. The shower plate 5 supplies a process gas (hereinafter referred to as "film formation gas") toward the substrate 10. Therefore, the space 31 is formed between the shower plate 5 and the electrode flange 4.

The shower plate 5 is provided with a plurality of second gas ejection openings 6. The film forming gas introduced into the space 31 is ejected into the chamber 2 through the second gas ejection opening 6.

The electrode flange 4 and the shower plate 5 are both made of a conductive material. The electrode flange 4 is connected to the RF power supply 33 (high frequency power supply) which is a voltage application part provided in the exterior of the chamber 2.

The RF power source 33 applies a high frequency voltage between the first electrode part made of the shower plate 5 and the second electrode part made of the support part 15. In accordance with the application of the high frequency voltage, the film forming gas supplied through the second gas ejection opening 6 toward the substrate 10 becomes a plasma state.

The support part 15 is a plate-like member with a flat surface like the base plate 3. The substrate 10 is placed on the upper surface of the support 15. Since this support part 15 functions as a ground electrode, the material which has electroconductivity is employ | adopted as the material of the support part 15. As shown in FIG. When the substrate 10 is placed on the support 15, the substrate 10 and the shower plate 5 are located in parallel and in close proximity to each other. When the film forming gas is ejected through the gas ejection opening 6 in a state where the substrate 10 is disposed on the support 15, the film forming gas is supplied to the processing surface of the substrate 10.

Moreover, the heater 16 which controls temperature is provided in the inside of the support part 15, and the temperature of the support part 15 is adjustable. This heater 16 is made of aluminum alloy, for example. The heater 16 protrudes from the back surface 17 of the substantially center portion of the support part 15 seen in the vertical direction of the support part 15. The heater 16 is inserted into the through hole 18 and the support 25 formed in the substantially center portion of the base plate 3 viewed from the vertical direction of the base plate 3, and is led out of the chamber 2. It is. The heater 16 is connected to a power supply (not shown) outside the chamber 2, and adjusts the temperature of the support part 15.

In addition, a gas introduction pipe 24 different from the exhaust pipe 28 is connected to the chamber 2. The gas inlet tube 24 is provided with a fluorine gas supply unit 22 via a radical source 23. The radical source 23 decomposes the fluorine gas supplied from the fluorine gas supply unit 22. The gas introduction pipe 24 supplies the fluorine radicals obtained by decomposing fluorine gas to the film formation space in the chamber 2.

In addition, the gas flanges 7A, 7B, and 7C are connected to the electrode flange 4. In addition, the electrode flange 4 is provided with a plurality of gas inlets 34A, 34B, and 34C. The gas introduction pipes 7A, 7B and 7C connect the source gas supply parts 21A, 21B and 21C and the gas introduction ports 34A, 34B and 34C respectively provided outside the chamber 2. The gas inlets 34A, 34B, and 34C are formed from the source gas supply unit 21 through the gas inlet pipes 7A, 7B, and 7C in the space 31 and the deposition gas (for example, monosilane (SiH ₄ ) gas). Hydrogen (H ₂ ) gas).

The source gas supply part 21 is comprised by the some source gas supply part 21A, 21B, 21C. The source gas supply parts 21A, 21B, 21C independently supply (discharge) the process gases of different compositions or types into the space 31. In each of the source gas supply units 21A, 21B, and 21C, the mixing ratio of the gas included in the deposition gas, for example, the mixing ratio of the hydrogen gas and the monosilane gas, can be adjusted before performing the deposition process. As shown in FIG. 1, in this embodiment, the source gas supply part 21 is comprised by three source gas supply parts 21A, 21B, and 21C.

In addition, the gas introduction pipe 7 is connected to the source gas supply parts 21A, 21B, and 21C, respectively, and is in the middle between the source gas supply parts 21A, 21B, and 21C, and the gas introduction ports 34A, 34B, and 34C, respectively. Three sets of gas introduction pipes 7A, 7B, and 7C branched into these two paths are included.

Moreover, in the space 31, the gas supply part 8 which guides the film-forming gas of a different composition or a kind independently to the shower plate 5 is arrange | positioned. The gas supply part 8 is formed by the tube which has the flow path which gas flows inside. Each of the plurality of gas supply units 8 is arranged concentrically and annularly. That is, the center positions of each of the plurality of gas supply units 8 coincide (see FIG. 3). Each of the annular portions is provided with a plurality of first gas ejection openings 9. In this embodiment, the gas supply part 8 is comprised by the three annular parts 8A, 8B, 8C, as shown in FIG. 2 or 3, a plurality of first gas ejection openings 9A are disposed in the first annular portion 8A located inside. A plurality of first gas ejection openings 9C are disposed in the third annular portion 8C located outside. A plurality of first gas ejection openings 9B are disposed in the second annular portion 8B positioned between the first annular portion 8A and the third annular portion 8C (middle position).

In addition, such a gas supply part 8 communicates with the some gas introduction port 34A, 34B, 34C provided in the electrode flange 4, respectively. In this embodiment, a configuration in which two gas inlets communicate with the annular portion in one annular portion constituting the gas supply part 8 is shown. That is, the first annular portion 8A communicates with the two gas inlets 34A, the second annular portion 8B communicates with the two gas inlets 34B, and the third annular portion 8C It is in communication with two gas inlet ports 34C. Each of the three annular portions 8A, 8B, 8C is connected to the gas introduction pipes 7A, 7B, 7C via gas introduction ports 34A, 34B, 34C.

In the present embodiment, the plurality of connection points (positions of the gas inlets 34A, 34B, 34C) to which the gas supply units 8 (8A, 8B, 8C) and the gas inlet pipes 7A, 7B, 7C are connected are provided. It is arrange | positioned symmetrically based on the center of an annular part. Moreover, the gas introduction pipe mentioned above is connected to two places of gas supply parts 8A, 8B, and 8C, respectively.

That is, as shown in Fig. 2, the connection point to which the annular portions 8A, 8B and 8C and the gas introduction pipes 7A, 7B and 7C are connected is based on line symmetry based on the center line CL intersecting in the longitudinal direction of the annular portion. Is located. In other words, the connection point is arrange | positioned at the center part of the lateral direction of an annular part.

On the other hand, as shown in Fig. 3, the connection points to which the annular portions 8A, 8B and 8C and the gas introduction pipes 7A, 7B and 7C are connected are located in point symmetry based on the center O of the annular portion. In other words, connection points are arranged at respective parts of the annular part facing each other.

By arranging the connection points symmetrically (line symmetry or point symmetry) in this manner, the deposition gas having a nonuniformity in the proportion of the mixed gas or the concentration of each gas can be supplied into the space 31 based on the position of the connection point.

In addition, the gas supply part 8 which consists of annular part 8A, 8B, 8C can be suitably adjusted in order to obtain the distribution of the gas concentration supplied on the board | substrate 10 as desired.

For example, as will be described later, by adjusting the shape and structure of the annular portions 8A, 8B, and 8C, the hydrogen supplied to the periphery of the substrate 10 rather than the concentration of hydrogen supplied to the central portion of the substrate 10 is determined. It is possible to supply the source gas onto the substrate to lower the concentration.

Next, the case where it forms into the board | substrate 10 using the film-forming apparatus 1 which has the above-mentioned structure is demonstrated.

First, the pressure inside the chamber 2 is reduced using the vacuum pump 27.

The substrate 10 is loaded into the chamber 2 and placed on the support 15 with the chamber 2 maintained in vacuum.

Here, the support part 15 is located below the chamber 2 before putting the board | substrate 10 on. That is, since the distance between the support part 15 and the shower plate 5 is widened before the board | substrate 10 is carried in, the board | substrate 10 can be easily mounted on the support part 15 using a robot arm (not shown). Can be.

Then, after the substrate 10 is placed on the support 15, a lifting mechanism (not shown) is activated to lift the support 25 upward, and the substrate 10 placed on the support 15 also moves upward. do. Thereby, the space | interval of the shower plate 5 and the board | substrate 10 is determined as desired so that it may become the space | interval required for film-forming suitably, and this space | interval is maintained.

Thereafter, the film forming gas is supplied from the source gas supply units 21 (21A, 21B, 21C) to the gas introduction pipe 7, branched by the gas introduction pipes 7A, 7B, 7C, and the gas introduction ports 34A, 34B, 34C). The film forming gas is supplied to the first annular portion 8A, the second annular portion 8B, and the third annular portion 8C through the plurality of connection points described above, and the first gas ejection openings 9 (9A, 9B, 9C)) into the space 31 (discharge). In addition, the deposition gas is supplied from the space 31 into the chamber 2 via the second gas ejection opening 6.

Next, the RF power supply 33 is started to apply a high frequency voltage to the electrode flange 4.

Thereby, a high frequency voltage is applied between the shower plate 5 and the support part 15, and discharge generate | occur | produces, and the plasma P generate | occur | produces between the electrode flange 4 and the process surface (surface) of the board | substrate 10. FIG. The process gas is decomposed in the plasma P to generate a gas phase growth reaction on the processing surface of the substrate 10, and a thin film is formed on the processing surface of the substrate 10.

In this embodiment, a high frequency power supply (RF power supply) of 13.56 MHz or 27.12 MHz is used as the oscillation frequency. Moreover, in order to obtain the film-forming speed suitable for mass production using such a film-forming apparatus 1, the pressure of film-forming space is set to 100 Pa-300 Pa. Under this pressure condition, the distance (inter-electrode distance) between the shower plate 5 to which a voltage is applied and the support part 15 which is a ground electrode is generally about 15-25 mm.

In addition, since the film forming material adheres to the inner wall surface of the chamber 2 and the like after the film forming process is repeated several times, the inside of the chamber 2 is periodically cleaned.

In the cleaning process, the fluorine gas supplied from the fluorine gas supply unit 22 is decomposed by the radical source 23 to generate fluorine radicals, and the fluorine radicals pass through the gas inlet tube 24 connected to the chamber 2 to vacuum. It is supplied in the chamber 2. By supplying fluorine radicals to the film forming space in the chamber 2 in this manner, a chemical reaction occurs to remove the members disposed around the film forming space or deposits attached to the inner wall surface of the chamber 2.

As mentioned above, in this embodiment, the gas supply part 8 is provided in the space 31 provided between the electrode flange 4 and the shower plate 5. The gas supply portion 8 includes a plurality of concentrically arranged annular portions 8A, 8B, 8C that independently supply process gases of different compositions or types toward the shower plate 5. According to such a structure, the ratio of the mixed gas contained in a process gas before performing a film-forming process in consideration of the quantity of hydrogen radicals which generate | occur | produces by reaction of process gas (film-forming gas) (for example, the decomposition reaction of monosilane) is carried out. For example, it is possible to control (adjust) the mixing ratio of hydrogen gas and monosilane gas for every gas supply part. Therefore, the film-forming gas whose ratio of mixed gas or the density | concentration of each gas is nonuniform can be supplied (release) in space.

Thereby, the process gas supplied from the gas supply part and the ratio of the mixed gas or the concentration of each gas is nonuniform can be uniformly supplied to the reaction space in which the substrate 10 is arranged via the shower plate.

In addition, a process gas in a plasma state is obtained in the film formation space by application of a high frequency voltage. The process gas in the plasma state, hydrogen radicals generated from the hydrogen gas (H ^{* 1)} and the monosilane gas is generated hydrogen radical decomposition (H ^{* 2)} is the distribution of the total amount of the hydrogen radicals (H ^*) combined each other, the substrate (10 It does not scatter out of the phase or become uneven. Thus, hydrogen radicals in which the total amount of hydrogen radicals H ^* are uniform on the substrate 10 can be obtained.

Therefore, the hydrogen radicals can be uniformly exposed to the processing surface of the substrate 10 regardless of the position on the substrate 10 throughout the center to the peripheral portion of the substrate 10. As a result, the film having a homogeneous composition can be stably formed.

Moreover, the technical scope of this invention is not limited to the said embodiment, It is possible to add various changes in the range which does not deviate from the meaning of this invention. That is, the specific material, structure, etc. which were described in this embodiment are an example of this invention, and can be changed suitably.

For example, in the said embodiment, although the structure in which two connection points were provided in one annular part was employ | adopted as shown to FIG. 2 and FIG. 3, three or more connection points may be provided in an annular part as needed. In addition, the position of a connection point is suitably determined as needed.

In addition, although the said embodiment demonstrated the case where this invention was applied to the film-forming apparatus, it is not limited to a film-forming apparatus, You may apply this invention to an etching apparatus.

In this case, the process gas used for etching is suitably selected according to the kind of film etched on the board | substrate.

According to such an etching apparatus, the whole surface of the film | membrane on a process surface can be etched uniformly at a desired etching rate. In addition, when the resist pattern which has an opening part is formed on the film | membrane formed on the process surface, the film formed on the process surface can be etched according to the shape of an opening part.

Example

Next, an Example is described.

In this embodiment, the concentration of hydrogen contained in the process gas is adjusted using the above-described plasma processing apparatus 1, the amount of hydrogen radicals in the film formation space is made uniform, and a film is formed on the processing surface of the substrate to achieve film quality. In-plane uniformity was confirmed.

First, a rectangular transparent conductive oxide (TCO) substrate having a short side y of 1100 mm and a long side x of 1400 mm was prepared. In the plasma processing apparatus, the size of the shower plate 5 serving as the first electrode portion is 1300 mm × 1600 mm, and the size of the support portion 15 (susceptor incorporating the heater) serving as the second electrode portion is 1400 mm × 1700 mm. to be. Using this plasma processing apparatus, an i-type silicon layer (I layer) having a thickness of 1.5 탆 was formed on the surface of the substrate.

In addition, in the present embodiment, a process gas in which silicon-containing gas (silane gas: SiH ₄ ) and dilution gas (hydrogen gas: H ₂ ) that promotes reaction is mixed at a predetermined ratio as a source gas used for film formation. It supplied from each of the process gas supply parts 21 (21A, 21B, 21C).

In 8 A of 1st annular parts arrange | positioned inside the gas supply part 8, the flow volume of the silicon containing gas was set to 0.33 slm, and the flow volume of the dilution gas was set to 5.0 slm. In addition, in the 2nd annular part 8B arrange | positioned in the middle, the flow volume of a silicon containing gas was set to 0.33 slm, and the flow volume of a dilution gas was set to 4.7 slm. In addition, in 8 C of 3rd annular parts arrange | positioned at the outer side, the flow volume of the silicon containing gas was set to 0.33 slm, and the flow volume of the dilution gas was set to 4.3 slm. The gas supply in this embodiment is shown schematically as shown in FIG.

FIG. 5 is a schematic diagram showing the relationship between the amount (concentration) of hydrogen radicals included in the deposition space and the position on the substrate when the process gas is supplied (released) and reacted using the plasma processing apparatus 1 according to the present invention. .

In Fig. 5, the symbol " O " shown at the center of the horizontal axis represents the center portion on the substrate, and the left and right directions in the symbol " O "

In FIG. 5, the concentration of the hydrogen radical (H ^{* 1} ) which arises from hydrogen gas is shown by the dashed-dotted line, and the density | concentration of the hydrogen radical (H ^{* 2} ) which arises from the decomposition | disassembly of monosilane gas is shown by the ^double- dotted line. Radical, the amount of hydrogen radicals (H ^*) (H ^{* 1} and ^{* 2} H) is combined with each other are shown by solid lines.

As shown in Fig. 5, in the present embodiment using the plasma processing apparatus 1 according to the present invention, the hydrogen radical (H * 1) generated from the hydrogen gas contained in the source gas by using the gas supply unit 8 is used. The process gas is adjusted so that the concentration is lowered toward the end (peripheral) of the substrate. That is, the process gas is adjusted so that the ratio of the mixed gas or the concentration of each gas becomes nonuniform, and the process gas is supplied onto the substrate. That is, the gas supply part 8 supplies source gas on a board | substrate so that the density | concentration of hydrogen supplied to the periphery of a board | substrate may be lower than the density | concentration of hydrogen supplied to the center part of a board | substrate.

In the plasma processing apparatus 1 of the present embodiment, the first annular portion 8A has a size of 250 mm x 325 mm, the pipe diameter is 1/2 inch, and the opening diameter of the first gas ejection port 9A is 1 mm. The pitch (interval) of one gas ejection port 9A was 30 mm.

Further, the second annular portion 8B has a size of 500 mm x 650 mm, the pipe diameter is 1/2 inch, the opening diameter of the first gas ejection port 9B is 1 mm, and the pitch of the first gas ejection port 9B ( Spacing) was 30 mm.

Further, the third annular portion 8C has a size of 1100 mm x 1300 mm, the pipe diameter is 1/2 inch, the opening diameter of the first gas ejection port 9C is 1 mm, and the pitch of the first gas ejection port 9C ( Spacing) was 30 mm.

In addition, as the film forming condition, the frequency of the high frequency power supply 33 is 27.12 MHz, the power density of the high frequency is 1.2 W / cm 2, the distance between the shower plate and the substrate is 10 mm, and the pressure is 700 Pa.

And, in order to measure the film quality of the thin film formed on the board | substrate, the some measuring point which is symmetrical with each other on the board | substrate was selected. As a measurement point, three points which consist of A point located in the upper left part of a board | substrate, B point located in the center part of a board | substrate, and C point located in the lower right part of a board | substrate were selected as shown in FIG. The size of A, B, and C points is 25 mm x 25 mm, respectively.

The thin film formed at each measuring point was evaluated by Raman spectroscopy. More specifically, the crystallization rate by observing a peak intensity (Ia) of the peak intensity due to the amorphous Si (Ic) and 480cm ^-1 due to the Si crystal of 520cm ^-1 in a Raman scattering spectrum, and dividing the Ic by Ia (Ic / Ia) was obtained. The crystallization rate of the thin film formed at each measurement point was evaluated. Table 1 shows the results of the evaluation of this example.

On the other hand, using the conventional plasma processing apparatus 101 described above as a comparative example, an I layer was formed on the surface of the TCO substrate with a film thickness of 1.5 탆 as in the above embodiment.

In the comparative example, the source gas used for film-forming was supplied through the gas introduction pipe 107, the flow volume of the silicon containing gas was set to 1 slm as the gas flow volume, and the flow volume of the dilution gas was set to 15 slm. The thin film formed by the comparative example was evaluated by Raman spectroscopy like the said Example. Table 1 shows the evaluation results of the comparative examples.

Example Comparative Example location Ic strength
(cm ^-1 ) Ia strength
(cm ^-1 ) Crystallization rate
(Ic strength /
Ia strength) Ic strength
(cm ^-1 ) Ia strength
(cm ^-1 ) Crystallization rate
(Ic strength /
Ia strength) A point 518.3 480 5.4 517.1 480 4.2 B point 518.5 480 5.6 519.2 480 6.6 C point 518.2 480 5.4 517.4 480 3.9

The evaluation result of the crystallization rate shown in Table 1 shows that when the plasma processing apparatus of this invention was used, the film | membrane which has a homogeneous composition could be formed on the process surface of a board | substrate. On the other hand, when using the conventional plasma processing apparatus, it turns out that the film | membrane which has a homogeneous composition is not obtained compared with this invention.

As described above, like the plasma processing apparatus of the present invention, a gas supply portion composed of a plurality of annular portions arranged concentrically is arranged in a space provided between the electrode flange and the shower plate. Thereby, it is possible to independently supply process gases having different mixing ratios toward the shower plate, and the amount (concentration) of the hydrogen radicals contained in the process gas (film forming gas) supplied to the shower plate is adjusted. have. Therefore, as is clear from the evaluation results in the above embodiments, the plasma processing can be uniformly performed on the processing surface of the substrate in the region from the center portion to the peripheral portion of the processing surface of the substrate, and a film having a homogeneous composition is formed on the substrate. I can see that I could.

In the case of using a conventional plasma processing apparatus, the composition of the film formed on the substrate was a heterogeneous composition depending on the position of the substrate. On the other hand, when using the plasma processing apparatus of this invention, it turns out that the film | membrane which has a uniform composition can be formed as a whole on the board | substrate irrespective of the position on a board | substrate.

Moreover, in the said Example, although the case where I layer was formed using the process gas which mixed monosilane and hydrogen was described, this invention is not limited to this. When forming a p-type silicon layer (P layer) or an n-type silicon layer (N layer) using the process gas which mixed monosilane and hydrogen, gas other than the process gas which mixed monosilane and hydrogen may be employ | adopted. . For example, the present invention can be carried out even when a combination of germane (GeH ₄ ) or disilane (Si ₂ H ₆ ) and hydrogen, or a combination of disilane, germane and hydrogen is used.

The plasma processing apparatus according to the present invention can be used in various semiconductor manufacturing fields such as a liquid crystal display or a solar cell, and in particular, the production of a solar cell using microcrystal silicon, which requires a high speed of film formation from the viewpoint of productivity. Useful for

α reaction chamber, 1 film forming apparatus (plasma processing apparatus), 2 chambers, 3 base plates, 4 electrode flanges, 5 shower plates, 6 second gas outlets, 7 (7A, 7B, 7C) gas introduction tubes, 8 (8A, 8B, 8C) Gas supply part, 9th gas outlet, 10 board | substrates (process object), 15 support part, 16 heaters, 21 (21A, 21B, 21C) source gas supply part, 31 spaces, 33 RF power supply (high frequency power supply, voltage application) 34A, 34B, 34C gas inlet, 81 insulated flange

Claims (7)

A plasma processing apparatus comprising:
A processing chamber comprising a chamber, an electrode flange having a plurality of gas inlets, and an insulating flange interposed by the chamber and the electrode flange;
A support part accommodated in the reaction chamber, a substrate is placed, and controlling a temperature of the substrate;
A shower plate accommodated in the reaction chamber, disposed to face the substrate, and supplying a process gas toward the substrate;
It is provided in the space between the electrode flange and the shower plate, and arranged in concentric and annular communication with each of the plurality of gas inlet port, a plurality of independent supply of the process gas of different composition toward the shower plate Gas supply unit;
And a voltage applying unit configured to apply a voltage between the shower plate and the support unit.
The process gas is a mixed gas comprising a gas containing at least hydrogen gas and silicon,
The substrate concentration of the hydrogen radicals (H ^*) plus the concentration of the hydrogen radicals (H ^{* 2)} generated from a gas containing the concentration and the silicon of the hydrogen radicals (H ^{* 1)} generated from the hydrogen gas from the central portion of the substrate The mixed gas ratio or the mixed gas concentration of the process gas is adjusted and supplied so as to be uniform over the periphery of the plasma processing apparatus. The method of claim 1,
And the plasma processing apparatus is a film forming apparatus. The method of claim 1,
The plasma processing apparatus is an etching apparatus. 4. The method according to any one of claims 1 to 3,
And the gas supply unit supplies the process gas onto the substrate so that the concentration of hydrogen supplied to the peripheral portion of the substrate is lower than the concentration of hydrogen supplied to the central portion of the substrate. 4. The method according to any one of claims 1 to 3,
Plasma processing apparatus, characterized in that the distance between the shower plate and the support is 15 ~ 25 mm. In the film formation method of micro crystalline silicon,
Set the distance between the support on which the substrate is placed and the shower plate to 15-25 mm,
Source gas containing a gas containing hydrogen gas and silicon is supplied from the shower plate onto the substrate,
Generating a plasma between the shower plate and the support,
Forming a micro crystalline silicon film on the substrate by plasma CVD;
The substrate concentration of the hydrogen radicals (H ^*) plus the concentration of the hydrogen radicals (H ^{* 2)} generated from a gas containing the concentration and the silicon of the hydrogen radicals (H ^{* 1)} generated from the hydrogen gas from the central portion of the substrate The mixed gas ratio or the mixed gas concentration of the process gas is adjusted and supplied so as to be uniform over the periphery of the microcrystalline silicon film deposition method. The method according to claim 6,
And depositing a concentration of hydrogen supplied to the periphery of the substrate lower than that of hydrogen supplied to the central portion of the substrate.

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