JP2006237093A - Plasma processing apparatus and method of plasma processing using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus which can accelerate a depositing speed while suppressing the decrease of a film quality. <P>SOLUTION: This plasma processing apparatus includes an upper electrode 3 which is installed in a vacuum chamber 2 and which can hold a substrate 10, a gas supply port 14 installed so that it may counter with the upper electrode 3 in the vacuum chamber 2, and a lower electrode 4 having gas suction ports (gas suction ports 24a and 24b) of the number more than the number of the gas supply ports 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method using the same, and more particularly to a plasma processing apparatus including a first electrode and a second electrode disposed so as to face each other and a plasma processing method using the same.

  2. Description of the Related Art Conventionally, a parallel plate type plasma processing apparatus including a first electrode capable of holding a substrate and a second electrode arranged to face the first electrode is known.

  FIG. 11 is a schematic view showing a conventional parallel plate type plasma processing apparatus. Referring to FIG. 11, in a conventional parallel plate type plasma processing apparatus 101, an upper electrode (first electrode) 103 and a lower electrode (second electrode) 104 are installed in a vacuum chamber 102 so as to face each other. Has been. The upper electrode 103 is configured to hold the substrate 110 on the side facing the lower electrode 104. A plurality of gas supply ports 114 for supplying a source gas are provided on the side of the lower electrode 104 facing the upper electrode 103. In addition, an exhaust port 102 a is provided on one side surface of the vacuum chamber 102, and the exhaust port 102 a is connected to the vacuum exhaust facility 106 via an exhaust flow rate adjustment valve 105. The gas supply port 114 of the lower electrode 104 is connected to the source gas supply source 107.

  In the conventional parallel plate type plasma processing apparatus 101 described above, the region 101 a between the upper electrode 103 and the lower electrode 104 becomes a region where plasma is generated, and the region 101 a between the upper electrode 103 and the lower electrode 104. The source gas is decomposed by the plasma generated in Further, in the configuration of the conventional parallel plate type plasma processing apparatus 101 described above, unreacted gas (raw material gas) that has not been decomposed, negative ions, malignant radicals, and flakes that are generated when the raw material gas is decomposed ( Fine particles generated by the polymerization reaction of negative ions) and the like are discharged through an exhaust port 102a provided on one side surface of the vacuum chamber 102.

  However, in the conventional parallel plate type plasma processing apparatus 101 shown in FIG. 11, discharge of unreacted gas (source gas), negative ions, malignant radicals, flakes and the like generated by decomposition of the source gas is performed. Since only the exhaust port 102a provided on one side surface of the vacuum chamber 102 is used, when a film having a large area is formed by depositing a film-forming species on the substrate 110, the exhaust port 102a side of the substrate 110 is used. And the discharge amount of the unreacted gas (raw material gas) and the reaction product in the region opposite to the exhaust port 102a of the substrate 110 becomes large. This disadvantageously makes it difficult to make the film quality of the film deposited on the substrate 110 uniform.

  Therefore, conventionally, in order to suppress variation in the discharge amount of unreacted gas (raw material gas) and reaction products depending on the region, unreacted gas (raw material gas) or reaction product is formed on one of the two electrodes facing each other. A parallel plate type plasma processing apparatus provided with an exhaust port for discharging an object has been proposed (see, for example, Patent Documents 1 and 2).

  Patent Document 1 discloses a plasma processing apparatus including an upper electrode having a plurality of gas supply ports and one exhaust port. Further, Patent Document 2 discloses a plasma processing apparatus including an upper electrode having a plurality of gas supply ports and a plurality of exhaust ports smaller than the number of gas supply ports. In Patent Documents 1 and 2, the substrate is fixed to the lower electrode.

  In the plasma processing apparatuses disclosed in Patent Documents 1 and 2, the conventional plasma processing apparatus 101 in which the upper electrode is provided with an exhaust port 102a by providing an exhaust port on one side surface of the vacuum chamber 102. Compared with (refer to FIG. 11), since it is suppressed that the discharge | emission amount of unreacted gas (raw material gas) and a reaction product changes with areas | regions, it becomes possible to suppress that film quality becomes non-uniform | heterogenous.

Japanese Patent Laid-Open No. 9-223865 Japanese Patent Laid-Open No. 11-144891

  However, the plasma processing apparatuses disclosed in Patent Documents 1 and 2 have the following inconveniences when the film forming speed is increased by supplying a large amount of source gas from the gas supply port of the upper electrode. That is, in Patent Documents 1 and 2, unreacted gas (raw material gas) that has not been decomposed due to supplying a large amount of raw material gas, or negative ions that are generated when the raw material gas is decomposed, When a large amount of malignant radicals and flakes (fine particles generated by a negative ion polymerization reaction) are generated, the number of exhaust ports provided in the upper electrode is smaller than the number of gas supply ports, so a large amount is generated. It becomes difficult to efficiently discharge unreacted gas (source gas), negative ions, malignant radicals and flakes through the exhaust port. As a result, the amount of unreacted gas (raw material gas), malignant radicals and flakes mixed in the film increases, resulting in inconvenience that the film quality deteriorates. As a result, Patent Documents 1 and 2 have a problem that it is difficult to increase the deposition rate while suppressing deterioration of the film quality.

  The present invention has been made to solve the above-described problems, and one object of the present invention is to provide a plasma processing apparatus capable of increasing the deposition rate while suppressing deterioration of the film quality. Is to provide.

  Another object of the present invention is to provide a plasma processing method using a plasma processing apparatus capable of increasing a film forming speed while suppressing deterioration in film quality.

Means for Solving the Problems and Effects of the Invention

  To achieve the above object, a plasma processing apparatus according to a first aspect of the present invention is provided in a plasma processing chamber and is capable of holding a substrate, and is opposed to the first electrode in the plasma processing chamber. And a second electrode having a gas supply port and a larger number of gas suction ports than the number of gas supply ports.

  In the plasma processing apparatus according to the first aspect, as described above, the substrate can be held by the second electrode having the gas supply ports and the number of gas suction ports larger than the number of the gas supply ports. By disposing the first electrode so as to face the first electrode, unreacted gas (source gas), negative ions, malignant radicals are generated by a larger number of gas suction ports than the number of gas supply ports provided in the second electrode. And more flakes can be discharged from the gas suction port. That is, when supplying the source gas from the gas supply port of the second electrode and generating the deposition seed by decomposing the source gas by the plasma generated in the region between the first electrode and the second electrode, When the film forming speed is increased by supplying a large amount of source gas from the gas supply port of the second electrode, unreacted gas (source gas) that has not been decomposed or generated by being decomposed. Even if a large amount of negative ions, malignant radicals and flakes (fine particles generated by the polymerization reaction of negative ions) are generated, unreacted gas (raw gas) is provided by the gas suction ports provided more than the number of gas supply ports. ), Negative ions, malignant radicals and flakes can be efficiently discharged. Thereby, even if a large amount of source gas is supplied from the gas supply port of the second electrode, unreacted gas (source gas), malignant radicals and The mixing of flakes can be effectively suppressed. As a result, the film formation rate can be increased while effectively suppressing the deterioration of the film quality caused by the mixture of unreacted gas (raw material gas), malignant radicals and flakes.

  In the plasma processing apparatus according to the first aspect, preferably, a region in which plasma is generated in the plasma processing chamber is such that the supply direction of the gas supplied from the gas supply port and the suction direction of the gas sucked by the gas suction port are It is comprised so that it may intersect. If comprised in this way, the area | region where the plasma between the 1st electrode and the 2nd electrode generate | occur | produces the supply direction of the gas supplied from a gas supply port, and the suction direction of the gas attracted | sucked by a gas suction port. Compared to the case where the gas does not cross in the gas flow, the gas flow from the gas supply port of the second electrode to the gas suction port is considered to be smoother, so that the gas suction of unreacted gas (source gas), negative ions, malignant radicals and flakes Ejection by mouth can be performed more efficiently.

  In the plasma processing apparatus according to the first aspect, preferably, the cross-sectional area of the main part of the first flow path of the gas supplied from the gas supply port is the main area of the second flow path of the gas sucked by the gas suction port. It is larger than the cross-sectional area of the part. If comprised in this way, a large amount of source gas can be supplied from a gas supply port. Moreover, since it can suppress that the source gas (unreacted gas) supplied from the gas supply port is discharged | emitted by a gas suction port too much, in the area | region where the plasma between a 1st electrode and a 2nd electrode generate | occur | produces. The residence time of the source gas can be increased. By these, since more film-forming seed | species can be produced | generated, the film-forming speed | rate can be made larger.

  In this case, preferably, the cross-sectional area of the main portion of the first flow path of the gas supplied from the gas supply port is the second flow of the gas sucked by the plurality of gas suction ports arranged in the vicinity of the gas supply port. It is larger than the sum of the cross-sectional areas of the main parts of the road. If comprised in this way, it can suppress easily that the source gas (unreacted gas) supplied from the gas supply port is discharged | emitted by a gas suction port too much.

  In the plasma processing apparatus according to the first aspect, preferably, the gas supply port has an inner surface shaped so that the opening area increases from the side opposite to the open end toward the open end, and gas suction is performed. The mouth is disposed on the inner surface of the gas supply port. If comprised in this way, since plasma can be concentrated and generated inside the inner surface of a gas supply port, the density of plasma can be made high. For this reason, since the source gas is efficiently decomposed by the high-density plasma, more film formation species can be generated. Thereby, the film-forming speed can be further increased. In this case, by disposing the gas suction port on the inner surface of the gas supply port, the distance between the region where the plasma is generated and the gas suction port can be reduced, so that unreacted gas (raw gas), negative ions, malignant Radicals and flakes can be efficiently discharged through the gas suction port.

  In the plasma processing apparatus according to the first aspect, preferably, a plurality of gas suction ports are arranged so as to be symmetric with respect to the center point of the gas supply port. With this configuration, it is possible to prevent the flow direction of the source gas supplied from the gas supply port from deviating in a predetermined direction, so that the film formation species in the predetermined region and regions other than the predetermined region It is possible to suppress the variation in the amount of produced. Thereby, it can suppress that film quality varies.

  The plasma processing method using the plasma processing apparatus according to the second aspect is installed in a plasma processing chamber and is arranged to face the first electrode in the plasma processing chamber and a first electrode capable of holding a substrate. A plasma processing method using a plasma processing apparatus comprising a gas supply port and a second electrode having a larger number of gas suction ports than the number of gas supply ports, wherein the substrate is formed by the first electrode. And holding a source gas from the gas supply port of the second electrode, and depositing film-forming seeds on the substrate, while the number of gas suction ports is larger than the number of gas supply ports of the second electrode. And a step of discharging unreacted gas and generated substances other than the film-forming species.

  In the plasma processing method using the plasma processing apparatus according to the second aspect, as described above, the source gas is supplied from the gas supply port of the second electrode to deposit the film forming species on the substrate. By discharging unreacted gas and generated substances other than the film-forming species through a larger number of gas suction ports than the number of gas supply ports of the electrode, the number of gas supply ports provided in the second electrode is more than that. A large number of gas suction ports can discharge more product substances (negative ions, malignant radicals and flakes) other than the film-forming species from the gas suction ports. That is, when increasing the deposition rate by supplying a large amount of source gas from the gas supply port of the second electrode, it is generated by decomposition of unreacted gas (source gas) that has not been decomposed or source gas. Even if a large amount of negative ions, malignant radicals and flakes (fine particles produced by the polymerization reaction of negative ions) are generated, unreacted gas (by the gas suction ports provided more than the number of gas supply ports) Source gas), malignant radicals and flakes can be efficiently discharged. Thereby, even if a large amount of source gas is supplied from the gas supply port of the second electrode, unreacted gas (source gas), malignant radicals and The mixing of flakes can be effectively suppressed. As a result, the film formation rate can be increased while effectively suppressing the deterioration of the film quality caused by the mixture of unreacted gas (raw material gas), malignant radicals and flakes.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic view showing a plasma processing apparatus according to a first embodiment of the present invention. 2 is a plan view showing a lower electrode of the plasma processing apparatus according to the first embodiment shown in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line 100-100 in FIG. 4 is a cross-sectional view of the gas flow path of the lower electrode shown in FIG. First, with reference to FIGS. 1-4, the structure of the plasma processing apparatus 1 by 1st Embodiment is demonstrated.

  As shown in FIG. 1, the plasma processing apparatus 1 according to the first embodiment has a parallel plate structure in which an upper electrode 3 and a lower electrode 4 are installed in a vacuum chamber 2 so as to face each other. In the plasma processing apparatus 1 according to the first embodiment, the region 1a between the upper electrode 3 and the lower electrode 4 is a region where plasma is generated. In addition, plasma is generated substantially uniformly in the region 1 a between the upper electrode 3 and the lower electrode 4. The vacuum chamber 2 is an example of the “plasma processing chamber” in the present invention. The upper electrode 3 and the lower electrode 4 are examples of the “first electrode” and the “second electrode” in the present invention, respectively.

  The upper electrode 3 is configured to be able to hold the substrate 10 on the side facing the lower electrode 4. The upper electrode 3 includes a heating / cooling mechanism (not shown) for maintaining the substrate 10 at a predetermined temperature.

  Here, in the first embodiment, the lower electrode 4 is supplied with raw material gas into the vacuum chamber 2, while the unreacted gas (raw material gas), negative ions generated when the raw material gas is decomposed, or malignant. It is configured such that radicals and flakes (fine particles generated by a negative ion polymerization reaction) can be discharged. Specifically, as shown in FIG. 2, a plurality of gas supply ports 14 for supplying a raw material gas to the side of the lower electrode 4 facing the upper electrode 3 (see FIG. 1) and an unreacted gas (raw material) Gas) and a plurality of gas suction ports 24a and 24b for discharging negative ions, malignant radicals, flakes and the like generated by the decomposition of the raw material gas. The plurality of gas supply ports 14 are arranged in a triangular lattice shape in plan view.

  In the first embodiment, a lid 14 b for changing the supply direction of the gas supplied from the gas supply port 14 is provided in a region corresponding to the open end of the gas supply port 14. The lid portion 14b is formed in a conical shape and is arranged so that the apex of the cone faces downward. As shown in FIG. 2, the lid portion 14 b is disposed at the center of the gas supply port 14 and is held by four columns 14 c. When the lid portion 14b as shown in FIG. 3 is provided at the center of the gas supply port 14, the flow direction of the source gas flowing in the direction perpendicular to the surface of the lower electrode 4 through the main portion 14d of the gas supply flow path is It is changed to supply directions A1 and A2 (see FIG. 3) along the side surface of the conical lid portion 14b. That is, the source gas supplied from the gas supply port 14 into the vacuum chamber 2 (see FIG. 1) is supplied in supply directions A1 and A2 (see FIG. 3) along the side surface of the conical lid portion 14b.

  In the first embodiment, as shown in FIG. 3, the gas suction port 24 a is disposed on the inclined inner surface 14 a of the gas supply port 14, and gas is sucked through a channel inclined at a predetermined angle. It is connected to the main part 24c of the flow path. The gas suction port 24b is also connected to the main portion 24c of the gas suction channel via a channel inclined at a predetermined angle. Therefore, the suction directions B1 and B2 (see FIG. 3) of the gas sucked by the gas suction ports 24a and 24b and the supply directions A1 and A2 (see FIG. 3) of the gas supplied from the gas supply port 14 are Crossing occurs in a region 1 a (see FIGS. 1 and 3) where plasma is generated between the upper electrode 3 and the lower electrode 4. In addition, as shown in FIG. 2, four gas suction ports 24 a are provided for each gas supply port 14, and one gas suction port 24 b is provided between adjacent gas supply ports 14. Is provided. That is, in the first embodiment, the number of gas suction ports including the gas suction ports 24 a and 24 b is configured to be larger than the number of gas supply ports 14. Further, the gas suction ports 24 a and 24 b are arranged so as to be symmetric with respect to the center point 50 of the gas supply port 14.

Moreover, in 1st Embodiment, as shown in FIG. 4, it is comprised so that the cross-sectional area of the main part 14d of a gas supply flow path may become larger than the cross-sectional area of the main part 24c of a gas suction flow path. Furthermore, in the first embodiment, the cross-sectional area of the main portion 14d of the gas supply flow path connected to the predetermined gas supply port 14 (see FIG. 3) has four gas suction ports corresponding to the predetermined gas supply port 14. 24a (see FIG. 3) and four gas suction ports 24b (see FIG. 3) are configured to be larger than the sum of the cross-sectional areas of the main portions 24c of the four gas suction channels. The diameter of the main portion 14d of the gas supply flow path is about 2.5 mm, and the cross-sectional area of the main portion 14d of the gas supply flow path is about 4.9 mm ² . The diameter of the main portion 24c of the gas suction channel is about 1 mm, and the cross-sectional area of the main portion 24c of the gas suction channel is about 0.79 mm ² . The sum of the cross-sectional areas of the main portions 24c of the gas suction flow paths connected to the four gas suction ports 24a corresponding to the predetermined gas supply ports 14 is about 3.16 mm ² (<about 4.9 mm ² ). is there. The main part 14d of the gas supply channel is an example of the “main part of the first channel” of the present invention, and the main part 24c of the gas suction channel is the “main part of the second channel” of the present invention. Is an example.

  As shown in FIG. 1, the vacuum chamber 2 has an exhaust port 2 a, and the exhaust port 2 a is connected to a vacuum exhaust system 6 through an exhaust flow rate adjustment valve 5. The gas supply port 14 of the lower electrode 4 is connected to the source gas supply source 7. The gas suction ports 24 a and 24 b of the lower electrode 4 are connected to the vacuum exhaust equipment 6 via the exhaust flow rate adjusting valve 8.

  In the first embodiment, as described above, the lower electrode 4 having the gas supply ports 14 and a larger number of gas suction ports (gas suction ports 24a and 24b) than the number of the gas supply ports 14 is provided on the substrate 10. The gas suction ports (gas suction ports 24 a and 24 b) more in number than the number of gas supply ports 14 provided in the lower electrode 4. Thus, more unreacted gas (raw material gas), negative ions, malignant radicals and flakes can be discharged from the gas suction ports 24a and 24b. That is, when the source gas is supplied from the gas supply port 14 of the lower electrode 4 and the source gas is decomposed by the plasma generated in the region 1 a between the upper electrode 3 and the lower electrode 4, the film formation seed is generated. In addition, when the film forming speed is increased by supplying a large amount of source gas from the gas supply port 14 of the lower electrode 4, unreacted gas (source gas) that has not been decomposed or source gas is decomposed. Even if a large amount of negative ions, malignant radicals and flakes (fine particles generated by the polymerization reaction of negative ions) are generated, gas suction ports (gas suction ports) provided more than the number of gas supply ports 14 By 24a and 24b), unreacted gas (raw material gas), negative ions, malignant radicals and flakes can be efficiently discharged. As a result, even if a large amount of source gas is supplied from the gas supply port 14 of the lower electrode 4, an unreacted gas (source gas), malignant, is formed on the film formed by depositing the film-forming species on the substrate 10. It is possible to effectively suppress the mixing of radicals and flakes. As a result, the film formation rate can be increased while effectively suppressing the deterioration of the film quality caused by the mixture of unreacted gas (raw material gas), malignant radicals and flakes.

  In the first embodiment, the region in which plasma is generated is divided into the suction directions B1 and B2 of the gas sucked by the gas suction ports 24a and 24b and the supply directions A1 and A2 of the gas supplied from the gas supply port 14. By being configured to intersect at 1a, the supply directions A1 and A2 of the gas supplied from the gas supply port 14 and the suction directions B1 and B2 of the gas sucked by the gas suction ports 24a and 24b are the upper electrode. Since the gas flow from the gas supply port 14 to the gas suction ports 24a and 24b becomes smoother than in the case where the region 1a where the plasma is generated between the lower electrode 4 and the lower electrode 4 does not intersect, unreacted gas (raw material) Gas), negative ions, malignant radicals and flakes can be discharged more efficiently through the gas suction ports 24a and 24b. That.

In the first embodiment, the cross-sectional area (4.9 mm ² ) of the main portion 14 d of the gas supply flow path connected to the predetermined gas supply port 14 is set to four gas suctions corresponding to the predetermined gas supply port 14. The raw material supplied from the gas supply port 14 by making it larger than the sum total (3.16 mm ² ) of the cross-sectional areas of the main portions 24c of the four gas suction channels connected to the port 24a and the four gas suction ports 24b. Since the gas (unreacted gas) can be prevented from being exhausted excessively by the gas suction port 24a, the residence time of the source gas in the region 1a where the plasma between the upper electrode 3 and the lower electrode 4 is generated is lengthened. be able to. Thereby, since more film-forming seed | species can be produced | generated, the film-forming speed | rate can be made larger.

  In the first embodiment, the gas suction ports 24 a and 24 b are arranged so as to be symmetrical with respect to the center point 50 of the gas supply port 14, so that the source gas supplied from the gas supply port 14 Since it is possible to suppress the flow direction from being biased in a predetermined direction, it is possible to suppress variation in the discharge amount of the film forming species in the predetermined region and regions other than the predetermined region. Thereby, it can suppress that film quality varies.

  Next, a plasma processing method when a predetermined film is formed on the substrate 10 by the plasma processing apparatus 1 according to the first embodiment will be described with reference to FIGS.

  First, as shown in FIG. 1, after the substrate 10 is installed on the side of the upper electrode 3 of the plasma processing apparatus 1 facing the lower electrode 4, the vacuum exhaust equipment 6 connected to the exhaust port 2 a of the vacuum chamber 2 is used. The inside of the vacuum chamber 2 is evacuated.

  Next, the source gas is supplied to the region 1 a between the upper electrode 3 and the lower electrode 4 from the gas supply port 14 of the lower electrode 4 connected to the source gas supply source 7. At this time, in the first embodiment, as shown in FIG. 3, the source gas supplied from the gas supply port 14 is supplied in the supply directions A1 and A2 along the side surface of the conical lid portion 14b. Then, plasma is generated in the region 1 a between the upper electrode 3 and the lower electrode 4 by supplying high-frequency power to the lower electrode 4. As a result, the source gas is decomposed by the plasma, and a film formation seed is generated. At this time, in the region 1a between the upper electrode 3 and the lower electrode 4, an unreacted gas (raw material gas) that is not decomposed by plasma and a negative gas generated by the decomposition of the raw material gas by the plasma, in addition to the film forming species. There are ions and malignant radicals. There are also fine particles (flakes) produced by a negative ion polymerization reaction.

  At this time, in the first embodiment, in the lower electrode 4, while supplying the source gas through the gas supply port 14, more gas suction ports (gas suction ports 24 a and 24 b) than the number of the gas supply ports 14 are used. Then, unreacted gas (raw material gas), negative ions, malignant radicals and flakes are sucked in suction directions B1 and B2 intersecting supply directions A1 and A2. Thereby, in the first embodiment, when the film forming speed is increased by supplying a large amount of source gas from the gas supply port 14, a large amount of unreacted gas (source gas), negative ions, malignant radicals, flakes, and the like. Even if it occurs, unreacted gas (raw material gas), negative ions, malignant radicals and flakes can be efficiently discharged through the gas suction ports 24a and 24b. Therefore, even if a large amount of source gas is supplied from the gas supply port 14, an unreacted gas (source gas), malignant material is formed on the film formed by depositing the film-forming species on the substrate 10 (see FIG. 1). Since mixing of radicals and flakes can be suppressed, the film formation rate can be increased while suppressing deterioration in film quality.

  Note that unreacted gas (source gas), negative ions, malignant radicals, and flakes are also discharged from the exhaust port 2 a of the vacuum chamber 2.

  Thereafter, a film formation species generated by the decomposition of the source gas by plasma is deposited on the substrate 10, whereby a predetermined film (not shown) is formed on the substrate 10.

  Next, an experiment conducted for confirming the effects on the film forming speed and film quality of the first embodiment will be described. In this confirmation experiment, a microcrystalline Si according to Example 1 was formed on a substrate using a plasma processing apparatus including a lower electrode having a gas supply port and a number of gas suction ports larger than the number of gas supply ports. In addition to forming the film, the deposition rate when forming the microcrystalline Si film according to Example 1 and the dark conductivity of the formed microcrystalline Si film according to Example 1 were measured. As a comparative example with respect to Example 1, a microcrystalline Si film according to Comparative Example 1 is formed on a substrate using a plasma processing apparatus provided with a lower electrode having only a gas supply port. The deposition rate when forming the microcrystalline Si film and the dark conductivity of the formed microcrystalline Si film according to Comparative Example 1 were measured.

  Here, it is considered that a microcrystalline Si film having a high dark conductivity has a larger current flowing through crystal grain boundaries and crystal defects of the microcrystalline Si film. For example, when a microcrystalline Si film having a high dark conductivity is used for a semiconductor device such as a solar cell, it is considered that the leakage current in the microcrystalline Si film increases. That is, it can be said that the microcrystalline Si film having a low dark conductivity has better film quality than the microcrystalline Si film having a high dark conductivity.

Example 1
In Example 1, a microcrystalline Si film was formed on a glass substrate as the substrate 10 using the plasma processing apparatus 1 according to the first embodiment shown in FIG. The cross-sectional area of the main portion 14d (see FIG. 4) of the gas supply channel was set to 4.9 mm ² . The sum of the cross-sectional areas of the main portions 24c (see FIG. 4) of the gas suction flow paths connected to the four gas suction ports 24a and the four gas suction ports 24b corresponding to the predetermined gas supply port 14 is 3. It was set to 16 mm ² . The conditions for forming the microcrystalline Si film according to Example 1 are shown in Table 1 below.

上記表１を参照して、実施例１による微結晶系Ｓｉ膜を形成する際には、基板温度、反応圧力および高周波電力を、それぞれ、２００℃、１３３Ｐａおよび１００Ｗに設定した。また、実施例１による微結晶系Ｓｉ膜を形成する際の原料ガス流量を、ＳｉＨ_４ガス：２０ｓｃｃｍおよびＨ_２ガス：４００ｓｃｃｍに設定した。

Referring to Table 1 above, when forming the microcrystalline Si film according to Example 1, the substrate temperature, reaction pressure, and high frequency power were set to 200 ° C., 133 Pa, and 100 W, respectively. The raw material gas flow rates when forming the microcrystalline Si film according to Example 1 were set to SiH ₄ gas: 20 sccm and H ₂ gas: 400 sccm.

  When the microcrystalline Si film according to Example 1 is formed, the plasma treatment shown in FIG. 1 is performed in order to make the supply amount of the source gas and the reaction pressure in Example 1 and Comparative Example 1 the same value. By adjusting the exhaust flow rate adjusting valves 5 and 8 of the apparatus 1, the balance between the exhaust through the exhaust port 2a of the vacuum chamber 2 and the exhaust through the gas suction ports 24a and 24b of the lower electrode 4 was adjusted.

(Comparative Example 1)
In Comparative Example 1, a microcrystalline Si film was formed on a glass substrate as the substrate 110 using the plasma processing apparatus 101 shown in FIG. Note that the lower electrode 104 shown in FIGS. 5 and 6 was used as the lower electrode 104 of the plasma processing apparatus 101. Specifically, the lower electrode 104 used for forming the microcrystalline Si film according to Comparative Example 1 is provided with a plurality of gas supply ports 114 as shown in FIG. The plurality of gas supply ports 114 are arranged in a triangular lattice shape. Further, as shown in FIG. 6, the main part 114 a of the gas supply channel connected to the gas supply port 114 is formed to extend in a direction perpendicular to the surface of the lower electrode 104. Further, the main part 114a of the gas supply channel was manufactured to have a diameter of 1 mm and a cross-sectional area of 0.79 mm ² .

  Table 2 below shows the formation conditions when a microcrystalline Si film according to Comparative Example 1 is formed on a glass substrate using the plasma processing apparatus 101 shown in FIG.

上記表２を参照して、比較例１による微結晶系Ｓｉ膜を形成する際には、基板温度、反応圧力および高周波電力を、それぞれ、２００℃、１３３Ｐａおよび１００Ｗに設定した。また、比較例１による微結晶系Ｓｉ膜を形成する際の原料ガス流量を、ＳｉＨ_４ガス：２０ｓｃｃｍおよびＨ_２ガス：４００ｓｃｃｍに設定した。なお、比較例１による微結晶系Ｓｉ膜の形成条件は、上記実施例１による微結晶系Ｓｉ膜の形成条件と同じである。

Referring to Table 2 above, when forming the microcrystalline Si film according to Comparative Example 1, the substrate temperature, reaction pressure, and high frequency power were set to 200 ° C., 133 Pa, and 100 W, respectively. The raw material gas flow rates when forming the microcrystalline Si film according to Comparative Example 1 were set to SiH ₄ gas: 20 sccm and H ₂ gas: 400 sccm. The formation conditions of the microcrystalline Si film in Comparative Example 1 are the same as the formation conditions of the microcrystalline Si film in Example 1.

  And the film-forming speed | rate at the time of forming a microcrystal Si film | membrane on the above-mentioned conditions and the dark conductivity of the formed microcrystal Si film | membrane were measured about each of Example 1 and Comparative Example 1. FIG. The dark conductivity of the microcrystalline Si film according to Example 1 and Comparative Example 1 is as follows. On the microcrystalline Si film, two aluminum electrodes (5 mm × 1 cm) are arranged with an interval of 1 mm. Calculation was based on the current flowing between the two aluminum electrodes. The results are shown in Table 3 below.

上記表３を参照して、ガス供給口１４に接続されるガス供給流路の主要部１４ｄの断面積が４．９ｍｍ^２であるプラズマ処理装置１を用いた実施例１の成膜速度は、ガス供給口１０４に接続されるガス供給流路の主要部１０４ａの断面積が０．７９ｍｍ^２であるプラズマ処理装置１０１を用いた比較例１の成膜速度よりも大きくなることが判明した。具体的には、実施例１による微結晶系Ｓｉ膜を形成する際の成膜速度は、０．４５ｎｍ／ｓであり、比較例１による微結晶系Ｓｉ膜を形成する際の成膜速度は、０．３０ｎｍ／ｓであった。これは、実施例１による微結晶系Ｓｉ膜の形成に用いたプラズマ処理装置１（ガス供給流路の主要部１４ｄの断面積：４．９ｍｍ^２）では、比較例１による微結晶系Ｓｉ膜の形成に用いたプラズマ処理装置１０１（ガス供給流路の主要部１０４ａの断面積：０．７９ｍｍ^２）に比べて、プラズマが発生する領域１ａへの原料ガスの供給量が多くなったことにより、プラズマにより分解されて生成された成膜種が多くなったためであると考えられる。

With reference to Table 3 above, the film formation speed of Example 1 using the plasma processing apparatus 1 in which the cross-sectional area of the main part 14d of the gas supply flow path connected to the gas supply port 14 is 4.9 mm ² is It has been found that the film forming speed of the comparative example 1 using the plasma processing apparatus 101 in which the cross-sectional area of the main part 104a of the gas supply flow path connected to the gas supply port 104 is 0.79 mm ² is larger. Specifically, the deposition rate when forming the microcrystalline Si film according to Example 1 is 0.45 nm / s, and the deposition rate when forming the microcrystalline Si film according to Comparative Example 1 is 0.30 nm / s. This is because the plasma processing apparatus 1 (cross-sectional area of the main portion 14d of the gas supply flow path: 4.9 mm ² ) used for forming the microcrystalline Si film according to Example 1 is the microcrystalline Si film according to Comparative Example 1. Compared with the plasma processing apparatus 101 (cross-sectional area of the main part 104a of the gas supply flow path: 0.79 mm ² ) used for forming the plasma, the supply amount of the source gas to the region 1a where the plasma is generated is increased. This is probably because the number of film formation species generated by being decomposed by plasma increased.

In addition, referring to Table 3 above, plasma processing including a lower electrode 4 having a gas supply port 14 and a larger number of gas suction ports (gas suction ports 24 a and 24 b) than the number of gas supply ports 14. The dark conductivity of the microcrystalline Si film formed in Example 1 using the apparatus 1 is the same as that in Comparative Example 1 formed using the plasma processing apparatus 101 including the lower electrode 104 having only the gas supply port 114. It has been found that it is lower than the dark conductivity of the Si-based film. Specifically, the dark conductivity of the microcrystalline Si film according to Example 1 is 3.5 × 10 ⁻⁵ S / cm, and the dark conductivity of the microcrystalline Si film according to Comparative Example 1 is 6. It was 8 × 10 ⁻⁵ S / cm. This is because the plasma processing apparatus 1 used for forming the microcrystalline Si film according to Example 1 has an unreacted gas (raw material) as compared with the plasma processing apparatus 101 used for forming the microcrystalline Si film according to Comparative Example 1. Gas), negative ions, malignant radicals (such as SiH ₂ ), and flakes are efficiently discharged through the gas suction ports 24 a and 24 b of the lower electrode 4, so that unreacted gas (source gas), malignant radicals and This is probably because the flakes are suppressed from being mixed into the microcrystalline Si film.

Here, when a microcrystalline Si film is formed using a plasma processing apparatus, it is necessary to increase the flow rate ratio (hydrogen dilution ratio) of H ₂ gas to SiH ₄ gas to some extent. As described above, when the microcrystalline Si film is formed under the formation conditions in which the hydrogen dilution rate is set high, the partial pressure of the SiH ₄ gas containing Si atoms constituting the microcrystalline Si film is reduced. The deposition rate of the Si film is reduced. Therefore, in order to increase the deposition rate when forming the microcrystalline Si film, it is necessary to increase the supply amount of high-frequency power. When the supply amount of high-frequency power is increased in this way, fine ions (flakes) of several nanometers to several micrometers can be produced by gas phase polymerization of negative ions generated by decomposition by plasma. is there. When the flakes described above are generated, the flakes adhere to the substrate, so that the flakes are mixed into the microcrystalline Si film formed on the substrate, so that the film quality of the microcrystalline Si film is deteriorated. There is an inconvenience. From this, when forming a microcrystalline Si film using a plasma processing apparatus, in order to increase the deposition rate and improve the film quality, as in the first embodiment, negative ions and It can be said that it is preferable to discharge flakes and the like efficiently.

  From these results, the plasma processing according to the first embodiment provided with the lower electrode 4 having the gas supply ports 14 and more gas suction ports (gas suction ports 24a and 24b) than the number of the gas supply ports 14. In the apparatus 1, even if the film forming rate is increased by supplying a large amount of source gas from the gas supply port 14 of the lower electrode 4, the discharge of unreacted gas (source gas), negative ions, malignant radicals and flakes is a gas. Since it is efficiently performed by the suction ports 24a and 24b, it is possible to confirm that unreacted gas (raw material gas), malignant radicals and flakes can be suppressed from being mixed into the film formed on the substrate. It was.

(Second Embodiment)
FIG. 7 is a schematic view illustrating a plasma processing apparatus according to a second embodiment of the present invention. FIG. 8 is a plan view showing a lower electrode of the plasma processing apparatus according to the second embodiment shown in FIG. 7, and FIG. 9 is a cross-sectional view taken along the line 300-300 in FIG. With reference to FIGS. 7 to 9, in the second embodiment, a plasma processing apparatus capable of increasing the plasma density will be described, unlike the first embodiment.

  That is, in the plasma processing apparatus 41 according to the second embodiment, the lower electrode 44 is installed in the vacuum chamber 2 so as to face the upper electrode 3 as shown in FIG. The lower electrode 44 is an example of the “second electrode” in the present invention.

  Here, in the second embodiment, the lower electrode 44 is not reactive gas (raw material gas) or negative ions generated when the raw material gas is decomposed while supplying the raw material gas into the vacuum chamber 2. It is configured such that radicals and flakes (fine particles generated by a negative ion polymerization reaction) can be discharged. Specifically, as shown in FIG. 8, on the side of the lower electrode 44 facing the upper electrode 3 (see FIG. 7), a plurality of gas supply ports 54 for supplying a source gas and unreacted gas (raw material) A plurality of gas suction ports 64 are provided for discharging gas, negative ions, malignant radicals, flakes, and the like generated when the raw material gas is decomposed.

  In the second embodiment, as shown in FIG. 9, the gas supply port 54 has an inner side surface 54a shaped so that the opening area increases from the side opposite to the open end toward the open end. When the gas supply port 54 having the inner side surface 54a as shown in FIG. 9 is provided, in addition to the region 41a (see FIG. 7) between the upper electrode 3 and the lower electrode 44, the inner side surface of the gas supply port 54 The region 41b inside 54a is also a region where plasma is generated. The density of plasma generated in the region 41 b inside the inner side surface 54 a of the gas supply port 54 is higher than the density of plasma generated in the region 41 a between the upper electrode 3 and the lower electrode 44. The gas supply port 54 is connected to a main portion 54 b of the gas supply channel that extends in a direction perpendicular to the surface of the lower electrode 44. As a result, the source gas supplied from the gas supply port 54 is supplied in the direction perpendicular to the surface of the lower electrode 44 (supply direction C (see FIG. 9)). Further, as shown in FIG. 8, the plurality of gas supply ports 54 are arranged in a triangular lattice shape in plan view.

  In the second embodiment, as shown in FIG. 9, the gas suction port 64 is disposed on the inclined inner surface 54 a of the gas supply port 54, and gas suction is performed via a channel inclined at a predetermined angle. It is connected to the main part 64a of the flow path. For this reason, the suction directions D1 and D2 of the gas sucked by the gas suction port 64 and the supply direction C of the gas supplied from the gas supply port 54 are regions (plasma) inside the inner side surface 54a of the gas supply port 54. In a region 41b). As shown in FIG. 8, four gas suction ports 64 are provided for each gas supply port 54. That is, in the second embodiment, the number of gas suction ports 64 is configured to be larger than the number of gas supply ports 54. Further, the gas suction port 64 is disposed so as to be symmetric with respect to the center point 60 of the gas supply port 54.

Further, in the second embodiment, as shown in FIGS. 8 and 9, the cross-sectional area of the main part 54 b of the gas supply flow path is configured to be larger than the cross-sectional area of the main part 64 a of the gas suction flow path. ing. Furthermore, in the second embodiment, the cross-sectional area of the main portion 54 b of the gas supply flow path connected to the predetermined gas supply port 54 is connected to the four gas suction ports 64 corresponding to the predetermined gas supply port 54. The gas suction channel is configured to be larger than the sum of the cross-sectional areas of the main part 64a. In addition, the diameter of the main part 54b of the gas supply channel is about 2.5 mm, and the cross-sectional area of the main part 54b of the gas supply channel is about 4.9 mm ² . The diameter of the main portion 64a of the gas suction channel is about 1 mm, and the cross-sectional area of the main portion 64a of the gas suction channel is about 0.79 mm ² . The sum of the cross-sectional areas of the main portions 64a of the gas suction flow paths connected to the four gas suction ports 64 corresponding to the predetermined gas supply ports 54 is about 3.16 mm ² (<about 4.9 mm ² ). is there. The main part 54b of the gas supply channel is an example of the “main part of the first channel” in the present invention, and the main part 64a of the gas suction channel is the “main part of the second channel” of the present invention. Is an example.

  In addition, the other structure of 2nd Embodiment is the same as that of the said 1st Embodiment.

  In the second embodiment, as described above, the substrate 10 can be held by the lower electrode 44 having the gas supply ports 54 and the gas suction ports 64 having a larger number than the number of the gas supply ports 54. By disposing the upper electrode 3 so as to face the upper electrode 3, as in the first embodiment, an unreacted gas (by the number of gas suction ports 64 larger than the number of gas supply ports 54 provided in the lower electrode 44). Source gas), negative ions, malignant radicals and flakes can be discharged from the gas suction port 64 more. That is, when the film forming rate is increased by supplying a large amount of source gas from the gas supply port 54 of the lower electrode 44, a large amount of unreacted gas (source gas), negative ions, malignant radicals and flakes are generated. However, unreacted gas (raw material gas), negative ions, malignant radicals and flakes can be efficiently discharged by the gas suction ports 64 provided more than the number of the gas supply ports 54. As a result, as in the first embodiment, the film formation rate can be increased while effectively suppressing the deterioration of the film quality caused by the mixture of unreacted gas (raw material gas), malignant radicals and flakes.

  Further, in the second embodiment, the plasma density (inside the inclined gas supply port 54 is formed by concentrating and generating the plasma in the region 41b inside the inclined inner side surface 54a of the gas supply port 54. The density of plasma generated in the region 41b inside the side surface 54a can be made higher than that in the first embodiment. For this reason, since the source gas is efficiently decomposed by the high-density plasma, more film formation species can be generated. Thereby, the film-forming speed can be made larger than that in the first embodiment. In this case, by disposing the gas suction port 64 on the inclined inner side surface 54a of the gas supply port 54, the distance between the region 41b where the plasma is generated and the gas suction port 64 can be reduced. Gas), negative ions, malignant radicals and flakes can be discharged more efficiently by the gas suction port 64.

  The remaining effects of the second embodiment are similar to those of the aforementioned first embodiment.

  Next, a plasma processing method when a predetermined film is formed on the substrate 10 by the plasma processing apparatus 41 according to the second embodiment will be described with reference to FIGS.

  First, as shown in FIG. 7, after the substrate 10 is installed on the side of the upper electrode 3 of the plasma processing apparatus 41 facing the lower electrode 44, the vacuum exhaust equipment 6 connected to the exhaust port 2 a of the vacuum chamber 2 is used. The inside of the vacuum chamber 2 is evacuated. Thereafter, as shown in FIGS. 7 and 9, the region 41 b inside the inner surface 54 a of the gas supply port 54 and the region 41 a between the upper electrode 3 and the lower electrode 44 are connected to the source gas supply source 7. The source gas is supplied in the supply direction C from the gas supply port 54 of the lower electrode 44.

  Next, in the second embodiment, by supplying high-frequency power to the lower electrode 44, a region 41 b inside the inner surface 54 a of the gas supply port 54, and a region 41 a between the upper electrode 3 and the lower electrode 44, To generate plasma. At this time, since plasma is concentrated and generated in the region 41 b inside the inner side surface 54 a of the gas supply port 54, the density of the plasma generated in the region 41 b inside the inner side surface 54 a of the gas supply port 54 is determined by the upper electrode 3. It becomes higher than the density of the plasma generated in the region 41a between the upper electrode 44 and the lower electrode 44. Thereby, in 2nd Embodiment, decomposition | disassembly of source gas is efficiently performed with a high-density plasma. Therefore, in the second embodiment, more film formation species can be generated than in the first embodiment, so that the film formation speed can be made larger than that in the first embodiment. At this time, in the region 41b inside the inner side surface 54a of the gas supply port 54 and the region 41a between the upper electrode 3 and the lower electrode 44, an unreacted gas (raw material gas) that is not decomposed by plasma other than the film forming species. In addition, there are negative ions and malignant radicals that are generated when the source gas is decomposed by plasma. There are also fine particles (flakes) produced by a negative ion polymerization reaction.

  At this time, in the second embodiment, in the lower electrode 44, while supplying the source gas through the gas supply port 54, the number of gas suction ports 64 is larger than the number of the gas supply ports 54 in the suction directions D1 and D2. Inhaling unreacted gas (source gas), negative ions, malignant radicals and flakes. Thereby, in the second embodiment, when the film forming speed is increased by supplying a large amount of source gas from the gas supply port 54, a large amount of unreacted gas (source gas), negative ions, malignant radicals, flakes, and the like are generated. Even if it occurs, unreacted gas (raw material gas), negative ions, malignant radicals and flakes can be efficiently discharged through the gas suction port 64. Therefore, even if a large amount of source gas is supplied from the gas supply port 54, an unreacted gas (source gas), malignant, is formed on the film formed by depositing the film-forming species on the substrate 10 (see FIG. 7). Since mixing of radicals and flakes can be suppressed, the film formation rate can be increased while suppressing deterioration in film quality.

  Thereafter, a film formation species generated by the decomposition of the source gas by plasma is deposited on the substrate 10, whereby a predetermined film (not shown) is formed on the substrate 10.

  Next, an experiment conducted for confirming the effects relating to the film forming speed and film quality of the second embodiment will be described. In this confirmation experiment, a microcrystalline Si according to Example 2 was formed on a substrate using a plasma processing apparatus including a lower electrode having a gas supply port and a number of gas suction ports larger than the number of gas supply ports. While forming the film, the film formation rate when forming the microcrystalline Si film according to Example 2 and the dark conductivity of the formed microcrystalline Si film according to Example 2 were measured. As a comparative example with respect to Example 2, the deposition rate when forming the microcrystalline Si film according to Comparative Example 1 described above and the dark conductivity of the microcrystalline Si film formed according to Comparative Example 1 were measured. The results were used.

(Example 2)
In Example 2, a microcrystalline Si film was formed on a glass substrate as the substrate 10 by using the plasma processing apparatus 41 according to the second embodiment shown in FIG. The cross-sectional area of the main portion 54b (see FIGS. 8 and 9) of the gas supply channel was set to about 4.9 mm ² . In addition, the sum of the cross-sectional areas of the main portions 64a (see FIGS. 8 and 9) of the gas suction flow paths connected to the four gas suction ports 64 corresponding to the predetermined gas supply ports 54 is about 3.16 mm ² . Set. The conditions for forming the microcrystalline Si film according to Example 2 are shown in Table 4 below.

上記表４を参照して、実施例２による微結晶系Ｓｉ膜を形成する際には、基板温度、反応圧力および高周波電力を、それぞれ、２００℃、１３３Ｐａおよび１００Ｗに設定した。また、実施例２による微結晶系Ｓｉ膜を形成する際の原料ガス流量を、ＳｉＨ_４ガス：２０ｓｃｃｍおよびＨ_２ガス：４００ｓｃｃｍに設定した。なお、実施例２による微結晶系Ｓｉ膜の形成条件は、上記実施例１および比較例１による微結晶系Ｓｉ膜の形成条件と同じである。

Referring to Table 4 above, when forming the microcrystalline Si film according to Example 2, the substrate temperature, reaction pressure, and high-frequency power were set to 200 ° C., 133 Pa, and 100 W, respectively. The raw material gas flow rates when forming the microcrystalline Si film according to Example 2 were set to SiH ₄ gas: 20 sccm and H ₂ gas: 400 sccm. The formation conditions of the microcrystalline Si film according to Example 2 are the same as the formation conditions of the microcrystalline Si film according to Example 1 and Comparative Example 1.

  When the microcrystalline Si film according to Example 2 is formed, the plasma treatment shown in FIG. 7 is performed in order to make the supply amount of the source gas and the reaction pressure in Example 2 and Comparative Example 1 the same value. By adjusting the exhaust flow rate adjusting valves 5 and 8 of the apparatus 41, the balance between the exhaust through the exhaust port 2a of the vacuum chamber 2 and the exhaust through the gas suction port 64 of the lower electrode 44 was adjusted.

  And the film-forming speed | rate at the time of forming a microcrystalline Si film | membrane on the above-mentioned conditions and the dark conductivity of the formed microcrystalline Si film | membrane were measured. The dark conductivity of the microcrystalline Si film was calculated using the same method as in Example 1 above. The results are shown in Table 5 below.

上記表５を参照して、ガス供給口５４に接続されるガス供給流路の主要部５４ａの断面積が４．９ｍｍ^２であるプラズマ処理装置４１を用いた実施例２の成膜速度は、ガス供給口１０４に接続されるガス供給流路の主要部１０４ａの断面積が０．７９ｍｍ^２であるプラズマ処理装置１０１を用いた比較例１の成膜速度よりも大きくなることが判明した。具体的には、実施例２による微結晶系Ｓｉ膜を形成する際の成膜速度は、０．５５ｎｍ／ｓであり、比較例１による微結晶系Ｓｉ膜を形成する際の成膜速度は、０．３０ｎｍ／ｓであった。これは、実施例２による微結晶系Ｓｉ膜の形成に用いたプラズマ処理装置４１（ガス供給流路の主要部５４ａの断面積：４．９ｍｍ^２）では、比較例１による微結晶系Ｓｉ膜の形成に用いたプラズマ処理装置１０１（ガス供給流路の主要部１０４ａの断面積：０．７９ｍｍ^２）に比べて、プラズマが発生する領域４１ａおよび４１ｂへの原料ガスの供給量が多くなったことにより、プラズマにより分解されて生成される成膜種が多くなったためであると考えられる。

With reference to Table 5 above, the film formation speed of Example 2 using the plasma processing apparatus 41 in which the cross-sectional area of the main part 54a of the gas supply flow path connected to the gas supply port 54 is 4.9 mm ² is It has been found that the film forming speed of the comparative example 1 using the plasma processing apparatus 101 in which the cross-sectional area of the main part 104a of the gas supply flow path connected to the gas supply port 104 is 0.79 mm ² is larger. Specifically, the deposition rate when forming the microcrystalline Si film according to Example 2 is 0.55 nm / s, and the deposition rate when forming the microcrystalline Si film according to Comparative Example 1 is 0.30 nm / s. This is because the plasma processing apparatus 41 used for forming the microcrystalline Si film according to Example 2 (the cross-sectional area of the main part 54a of the gas supply channel: 4.9 mm ² ) uses the microcrystalline Si film according to Comparative Example 1. Compared with the plasma processing apparatus 101 (cross-sectional area of the main part 104a of the gas supply flow path: 0.79 mm ² ) used for forming the gas, the amount of the source gas supplied to the regions 41a and 41b where the plasma is generated is increased. This is probably because the number of film formation species generated by being decomposed by plasma increases.

  In addition, referring to Table 3 and Table 5 above, implementation using a plasma processing apparatus 41 configured such that plasma is concentrated and generated in a region 41b inside the inner side surface 54a of the gas supply port 54 of the lower electrode 44. In Example 2, the deposition rate is higher than that in Example 1 using the plasma processing apparatus 1 configured to generate plasma substantially uniformly in the region 1 a between the upper electrode 3 and the lower electrode 4. It has been found. Specifically, the deposition rate when forming the microcrystalline Si film according to Example 2 is 0.55 nm / s, and the deposition rate when forming the microcrystalline Si film according to Example 1 is 0.45 nm / s. This is because the plasma processing apparatus 41 used for forming the microcrystalline Si film according to the second embodiment has a higher plasma density (gas) than the plasma processing apparatus 1 used for forming the microcrystalline Si film according to the first embodiment. This is probably because the density of plasma generated in the inner region 41b of the inner side surface 54a of the supply port 54 has increased, and the number of film formation species generated by being decomposed by the plasma has increased.

In addition, referring to Table 5, the plasma processing apparatus 41 including the lower electrode 44 having the gas supply ports 54 and the gas suction ports 64 having a larger number than the number of the gas supply ports 54 is used. The dark conductivity of the microcrystalline Si film according to Example 2 is equal to the dark conductivity of the microcrystalline Si film according to Comparative Example 1 formed using the plasma processing apparatus 101 including the lower electrode 104 having only the gas supply port 114. Turned out to be lower. Specifically, the dark conductivity of the microcrystalline Si film according to Example 2 is 4.3 × 10 ⁻⁵ S / cm, and the dark conductivity of the microcrystalline Si film according to Comparative Example 1 is 6. It was 8 × 10 ⁻⁵ S / cm. This is because the plasma processing apparatus 41 used for forming the microcrystalline Si film according to Example 2 has an unreacted gas (raw material) as compared with the plasma processing apparatus 101 used for forming the microcrystalline Si film according to Comparative Example 1. Gas), negative ions, malignant radicals (such as SiH ₂ ), and flakes are efficiently discharged through the gas suction port 64 of the lower electrode 44, so that unreacted gas (source gas), malignant radicals and flakes are removed. It is thought that this is because mixing into the microcrystalline Si film was suppressed.

  From these results, in the plasma processing apparatus 41 according to the second embodiment including the lower electrode 44 having the gas supply ports 54 and the number of gas suction ports 64 larger than the number of the gas supply ports 54, Similar to the embodiment, even if the film formation rate is increased by supplying a large amount of source gas from the gas supply port 54 of the lower electrode 44, unreacted gas (source gas), negative ions, malignant radicals and flakes are discharged. Since it is efficiently performed by the gas suction port 64, it was confirmed that it was possible to suppress the mixing of unreacted gas (raw material gas), malignant radicals and flakes into the film formed on the substrate. .

In addition, with reference to Table 3 and Table 5 above, implementation using a plasma processing apparatus 41 configured to generate plasma in a concentrated manner in a region 41b inside the inner side surface 54a of the gas supply port 54 of the lower electrode 44 is performed. In Example 2 (dark conductivity: 4.3 × 10 ⁻⁵ S / cm), a plasma processing apparatus configured to generate plasma substantially uniformly in the region 1 a between the upper electrode 3 and the lower electrode 4. It was found that the dark conductivity of the microcrystalline Si film was higher than that in Example 1 using 1 (dark conductivity: 3.5 × 10 ⁻⁵ S / cm). This is because in Example 2, since the amount of film formation species varied due to the decomposition of more source gas in the region 41b where the plasma was concentrated, the film quality became non-uniform. Conceivable.

  The embodiments and examples disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments and examples but by the scope of claims for patent, and includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the first embodiment and Example 1, the plurality of gas supply ports (main portions of the gas supply flow path) are arranged in a triangular lattice shape when seen in a plan view, and the center point of the gas supply ports However, the present invention is not limited to this, and a plurality of gas supply ports (main parts of the gas supply flow path) are arranged. May not be arranged in a triangular lattice pattern. For example, as shown in FIG. 10, a plurality of gas supply ports (main parts of the gas supply flow path) 71 are arranged in a matrix (matrix), and the gas supply ports (main parts of the gas supply flow path) 71 are arranged. A plurality of gas suction ports (main portions of the gas suction flow path) 72 may be arranged so as to be symmetric with respect to the center point 70 of the gas.

1 is a schematic diagram illustrating a plasma processing apparatus according to a first embodiment of the present invention. It is the top view which showed the lower electrode of the plasma processing apparatus by 1st Embodiment shown in FIG. FIG. 3 is a cross-sectional view taken along line 100-100 in FIG. 2. It is sectional drawing of the gas flow path of the lower electrode shown in FIG. 6 is a plan view showing a lower electrode of a plasma processing apparatus used when forming a microcrystalline Si film according to Comparative Example 1. FIG. It is sectional drawing along the 200-200 line | wire of FIG. It is the schematic which showed the plasma processing apparatus by 2nd Embodiment of this invention. It is the top view which showed the lower electrode of the plasma processing apparatus by 2nd Embodiment shown in FIG. It is sectional drawing along the 300-300 line | wire of FIG. It is the top view which showed the lower electrode of the plasma processing apparatus by the modification of 1st Embodiment. It is the schematic which showed the conventional parallel plate type plasma processing apparatus.

Explanation of symbols

1a, 41a, 41b Region 2 Vacuum chamber (plasma processing chamber)
3 Upper electrode (first electrode)
4, 44 Lower electrode (second electrode)
10 Substrate
14, 54 Gas supply port 14d, 54b Main part of gas supply channel (main part of first channel)
24a, 24b, 64 Gas suction port 24c, 64a Main part of gas suction channel (main part of second channel)
54a inner surface

Claims (7)

A first electrode installed in the plasma processing chamber and capable of holding a substrate;
A plasma processing comprising: a second electrode having a gas supply port and a number of gas suction ports larger than the number of the gas supply ports, which is installed in the plasma processing chamber so as to face the first electrode. apparatus.   The supply direction of the gas supplied from the gas supply port and the suction direction of the gas sucked by the gas suction port are configured to intersect each other in a region where plasma is generated in the plasma processing chamber. Item 2. The plasma processing apparatus according to Item 1.   The cross-sectional area of the main part of the first flow path of the gas supplied from the gas supply port is larger than the cross-sectional area of the main part of the second flow path of the gas sucked by the gas suction port. 2. The plasma processing apparatus according to 2.   The cross-sectional area of the main part of the first flow path of the gas supplied from the gas supply port is the second flow path of the gas sucked by the plurality of gas suction ports arranged in the vicinity of the gas supply port The plasma processing apparatus according to claim 3, wherein the plasma processing apparatus is larger than a sum of cross-sectional areas of main parts. The gas supply port has an inner surface shaped so that the opening area increases from the side opposite to the open end toward the open end,
The plasma processing apparatus according to claim 1, wherein the gas suction port is disposed on an inner surface of the gas supply port.   The plasma processing apparatus according to claim 1, wherein a plurality of the gas suction ports are arranged so as to be symmetric with respect to a center point of the gas supply port. A first electrode installed in the plasma processing chamber and capable of holding a substrate; and installed in the plasma processing chamber so as to face the first electrode; and more than a gas supply port and the number of the gas supply ports A plasma processing method using a plasma processing apparatus including a second electrode having a large number of gas suction ports,
Holding the substrate by the first electrode;
While depositing film-forming species on the substrate by supplying a source gas from the gas supply port of the second electrode, a larger number of the gas suction ports than the number of the gas supply ports of the second electrode A plasma processing method using a plasma processing apparatus, comprising: a step of discharging unreacted gas and a generated substance other than the film-forming species.

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