JP4937384B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus, and more particularly, to a plasma processing apparatus including a first electrode and a second electrode arranged to face each other.

  2. Description of the Related Art Conventionally, a parallel plate type plasma processing apparatus having a first electrode capable of holding a substrate and a second electrode disposed so as to face the first electrode and a film using the plasma processing apparatus Manufacturing methods are known (see, for example, Patent Documents 1 to 3).

  In the above-mentioned patent document 1, when the film forming speed is increased, a high-pressure atmosphere of about 665 Pa (5 Torr) or more is set, and a plasma CVD that sets a gap between the substrate and the counter electrode (second electrode) to about 10 mm or less. (Chemical Vapor Deposition) apparatus (plasma processing apparatus) is disclosed. In this plasma CVD apparatus, gas is supplied from the counter electrode (second electrode), and an exhaust channel for discharging gas containing silicon powder (product) holds the substrate (first electrode) And it is arrange | positioned to the side of a counter electrode (2nd electrode). Further, in Patent Document 1, a cylindrical flow path control plate is provided so as to surround the periphery of the substrate and the counter electrode, so that gas is exhausted from the exhaust flow path by passing above and below the flow path control plate. Like to do.

  In Patent Document 2, when increasing the film formation rate, a high-pressure atmosphere of about 1995 Pa (15 Torr) or more is used, and a gap between the ground electrode (first electrode) and the high-frequency supply electrode (second electrode) is set. Discloses a plasma CVD apparatus (plasma processing apparatus) that generates high-density plasma by setting it to about 6 mm or less. In this plasma CVD apparatus, a gas is supplied between the ground electrode and the high-frequency supply electrode, and a gas containing a product is exhausted from the side and the lower side of the ground electrode and the high-frequency supply electrode.

  Further, in Patent Document 3 described above, silicon is formed in a high-pressure atmosphere of about 399 Pa (3 Torr) or more in order to increase the film formation rate when forming a photoelectric conversion layer made of a silicon-based thin film using plasma CVD. A method for producing a thin film is disclosed.

  FIG. 18 is a schematic view showing a parallel plate type plasma processing apparatus according to a conventional example. FIG. 19 is an enlarged plan view of a lower electrode of the conventional parallel plate type plasma processing apparatus shown in FIG. 20 is an enlarged cross-sectional view of a lower electrode of the conventional parallel plate type plasma processing apparatus shown in FIG. Hereinafter, a conventional plasma processing apparatus 101 will be described with reference to FIGS. In a conventional parallel plate type plasma processing apparatus 101, as shown in FIG. 18, an upper electrode 103 and a lower electrode 104 are installed in a vacuum chamber 102 so as to face each other. The upper electrode 103 is formed with a substrate holding portion 103 a for holding the substrate 110 on the side facing the lower electrode 104. Further, as shown in FIGS. 19 and 20, a plurality of gas supply ports 104 a for supplying a source gas are provided on the surface of the lower electrode 104 facing the upper electrode 103. Further, as shown in FIG. 18, an exhaust port 102a is provided on one side surface of the vacuum chamber 102 (on the side of the upper electrode 103 and the lower electrode 104), and the exhaust port 102a has an exhaust flow rate adjustment. It is connected to an evacuation facility 106 through a valve 105. The evacuation facility 106 is constituted by a turbo molecular pump (TMP) 106a and an oil rotary pump (RP) 106b. The gas supply port 104 a 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, plasma is generated over the entire upper surface of the lower electrode 104, and the source gas is decomposed by the plasma. 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 ( Products such as fine particles generated by a negative ion polymerization reaction are discharged through an exhaust port 102 a provided on the side of the upper electrode 103 and the lower electrode 104.

JP-A-11-330520 JP 7-228965 A JP-A-11-145499

  However, in the conventional parallel plate type plasma processing apparatus 101 shown in FIG. 18, it is necessary to generate plasma in a high-pressure atmosphere when increasing the film forming speed. Thus, in order to generate plasma under a high pressure atmosphere, it is necessary to apply a large voltage. For this reason, since the power source for generating plasma becomes large, there is a problem that the apparatus is enlarged accordingly. Further, in the conventional plasma processing apparatus 101 shown in FIG. 18, since exhaust is performed through the exhaust port 102 b provided on one side, unreacted gas and product exhaust from the center of the substrate 110, The unreacted gas and the exhaust amount of the product from the end portion are likely to be uneven. In particular, in the conventional plasma processing apparatus 101, in order to increase the deposition rate, when generating plasma in a high-pressure atmosphere, it is necessary to reduce the gap between the upper electrode 103 and the lower electrode 104. When exhaust is performed from one side in a state where the gap between the upper electrode 103 and the lower electrode 104 is reduced as described above, the exhaust amount of unreacted gas and product from the center of the substrate 110 and the end of the substrate 110 are reduced. Since the unreacted gas from the part and the exhaust amount of the product tend to be more uneven, there is a problem that the film thickness and the film quality are likely to be uneven.

  In Patent Documents 1 to 3, since it is necessary to generate plasma under a high-pressure atmosphere in order to increase the deposition rate, plasma is generated as in the conventional plasma processing apparatus 101 shown in FIG. Therefore, there is an inconvenience that the power source for this becomes large. As a result, there is a problem that the apparatus becomes large.

  Further, in the plasma processing apparatus disclosed in Patent Document 1, by providing a cylindrical flow path control plate so as to surround the periphery of the substrate and the counter electrode, it is possible to alleviate the non-uniformity of the gas exhaust amount to some extent. Is possible. However, even when the flow path control plate is provided, the gas is exhausted toward the exhaust flow path provided on one side near the upper portion of the flow path control plate. As a result, there is an inconvenience that it is difficult to flow the reaction gas of the substrate and the counter electrode arranged inside the flow path control plate sufficiently uniformly. As a result, there is a problem that it is difficult to make the film thickness and film quality sufficiently uniform.

  Further, in the plasma processing apparatus disclosed in Patent Document 2, exhaust is performed by a flow path provided on both sides of the ground electrode and the high frequency supply electrode and a flow path provided below the high frequency supply electrode. It is possible to make the unreacted gas and product displacement from both ends of the substrate uniform. However, since the distance of the exhaust flow path is different between the central portion and the end portion of the substrate, the exhaust amount of the unreacted gas and product from the central portion of the substrate and the unreacted gas and product from the end portion of the substrate The amount of exhaust tends to be uneven. For this reason, there is a problem that the film thickness and film quality tend to be non-uniform.

  The present invention has been made in order to solve the above-described problems, and one object of the present invention is to increase the film forming speed and suppress the film thickness and film quality while suppressing an increase in the power source. It is an object of the present invention to provide a plasma processing apparatus capable of more effectively suppressing non-uniformity.

Means for Solving the Problems and Effects of the Invention

  In order to achieve the above object, a plasma processing apparatus according to an aspect of the present invention is disposed so as to face a first electrode capable of holding a substrate, face the first electrode, and face the first electrode. A second electrode in which a plurality of convex portions and a plurality of concave portions are formed in the portion, and a gas supply port for supplying gas is formed in one of the convex portion and the concave portion of the second electrode, A gas suction port for discharging gas is formed on the other of the convex portion and the concave portion of the two electrodes.

  In the plasma processing apparatus according to this aspect, as described above, the electric field is concentrated on the convex portion of the second electrode by providing the second electrode having a plurality of convex portions formed on the portion facing the first electrode. Therefore, high-density plasma can be generated between the first electrode and the second electrode. Thereby, since the decomposition efficiency of gas (raw material gas) can be improved, more film-forming seed | species can be formed. As a result, the deposition rate can be improved. In addition, a gas supply port for supplying gas is formed in one of the convex portion and the concave portion of the second electrode, and a gas suction port for discharging gas is provided in the other of the convex portion and the concave portion of the second electrode. By forming, the gas supply port and the gas suction port can be arranged uniformly in all regions of the second electrode. As a result, even when a high-pressure atmosphere is provided and the gap between the first electrode and the second electrode is reduced, unreacted gas and generation at the center and end portions of the substrate are generated by the gas suction port provided in the second electrode. Since the object can be discharged uniformly, the concentration of the source gas at the center and the end of the substrate can be made more uniform. Thereby, it can suppress more effectively that a film thickness and film quality become non-uniform | heterogenous.

  In the plasma processing apparatus according to the above aspect, preferably, a gas supply port for supplying gas is formed in the convex portion, and a plasma generation region centered on the convex portion and an adjacent convex portion are the center. A plurality of convex portions are arranged so as to overlap with the plasma generation region. If comprised in this way, since a plasma generation area | region can also be arrange | positioned also in the area | region between adjacent convex parts, a plasma generation area | region can be arrange | positioned in the whole surface of a 2nd electrode. Thereby, since the film-forming seed | species can be produced | generated on the whole surface of a 2nd electrode, even if it provides a convex part, it can suppress effectively that a film thickness and film quality become non-uniform | heterogenous.

In the plasma processing apparatus according to the above aspect, preferably, the recess is formed with a gas suction port for discharging gas, and further includes an insulating member disposed in a portion other than the gas suction port of the recess. If comprised in this way, when gas passes a recessed part and is discharged | emitted from a gas suction port, since the area of the part which the gas of a recessed part can pass can be made small by the arrangement | positioning of an insulating member, gas The flow rate of the gas near the suction port can be increased. Thereby, it can suppress that the flakes etc. which are contained in gas adhere to a recessed part. In this case, since the member arranged in the concave portion is formed of the insulating member, the electric field concentrated on the convex portion of the second electrode can be prevented from being dispersed. Therefore, even if the insulating member is provided, the plasma density Can be suppressed.

  In the plasma processing apparatus according to the above aspect, the substrate held by the first electrode is preferably configured to be swingable. With this configuration, the region corresponding to the convex portion of the second electrode having a high plasma density can be evenly distributed on the surface of the substrate during film formation by swinging the substrate. Moreover, it can suppress that a film thickness and film quality become non-uniform | heterogenous.

  In the plasma processing apparatus according to the above aspect, preferably, the plurality of concave portions are arranged in the vicinity of the convex portion in plan view, and the plurality of concave portions are arranged symmetrically with respect to the center of the convex portion. ing. With this configuration, for example, when the gas supply port is provided in the convex portion and the gas suction port is provided in the concave portion, the gas in the concave portion arranged symmetrically with respect to the center of the gas supply port of the convex portion. By the suction port, the unreacted gas and the product can be discharged more uniformly with respect to the gas supply port of the convex portion. Thereby, since source gas can be supplied more uniformly by the gas supply port of a convex part, it can suppress that a film thickness and film quality become non-uniform | heterogenous.

  In the plasma processing apparatus according to the above aspect, the convex portion and the concave portion are preferably formed so as to extend in a predetermined direction along the main surface of the substrate, and have a predetermined interval in a direction intersecting the predetermined direction. Spaced apart. If comprised in this way, since a gas supply port and a gas suction port can each be arrange | positioned along a predetermined direction, the uniformity of the film thickness and film quality along a predetermined direction can be improved. .

  In the plasma processing apparatus in which the convex portion and the concave portion are formed so as to extend in a predetermined direction along the main surface of the substrate, the gas supply port and the gas suction port are preferably in a predetermined direction along the main surface of the substrate. It is formed in a slit shape so as to extend. If comprised in this way, since a gas supply port and a gas suction port can each be arrange | positioned so that it may extend in a predetermined direction, the uniformity of the film thickness and film quality along a predetermined direction can be improved more Can do.

  In the plasma processing apparatus according to the above aspect, preferably, the width of the tip portion on the first electrode side of the convex portion of the second electrode is smaller than the width of the root portion of the convex portion of the second electrode. If comprised in this way, since an electric field can be concentrated more on the front-end | tip part of the convex part of a 2nd electrode, a higher-density plasma can be generated between a 1st electrode and a 2nd electrode. .

1 is a schematic diagram illustrating a plasma processing apparatus according to a first embodiment of the present invention. It is a front view of the periphery of the upper electrode and lower electrode of the plasma processing apparatus by 1st Embodiment shown in FIG. It is a top view of the lower electrode of the plasma processing apparatus by 1st Embodiment shown in FIG. It is sectional drawing along the 150-150 line | wire of FIG. FIG. 6 is a cross-sectional view taken along a line 160-160 in FIG. 3. It is an expanded sectional view of the convex part of the lower electrode of the plasma processing apparatus by 1st Embodiment shown in FIG. It is a top view for demonstrating in detail the experiment for confirming the effect of the plasma processing apparatus by 1st Embodiment shown in FIG. It is sectional drawing for demonstrating in detail the experiment for confirming the effect of the plasma processing apparatus by 1st Embodiment shown in FIG. It is a top view of the lower electrode of the plasma processing apparatus by 2nd Embodiment of this invention. It is sectional drawing along the 170-170 line of FIG. FIG. 10 is a cross-sectional view taken along line 180-180 in FIG. 9. It is sectional drawing for demonstrating the lower electrode of the plasma processing apparatus by the 1st modification of 1st Embodiment of this invention. It is a top view for demonstrating the lower electrode of the plasma processing apparatus by the 2nd modification of 1st Embodiment of this invention. It is sectional drawing along the 190-190 line of FIG. It is a top view for demonstrating the lower electrode of the plasma processing apparatus by the 3rd modification of 1st Embodiment of this invention. It is sectional drawing along the 200-200 line | wire of FIG. It is sectional drawing for demonstrating the lower electrode of the plasma processing apparatus by the 4th modification of 1st Embodiment of this invention. It is the schematic which showed the conventional parallel plate type plasma processing apparatus. It is a top view of the lower electrode of the conventional parallel plate type plasma processing apparatus shown in FIG. It is sectional drawing of the lower electrode of the conventional parallel plate type plasma processing apparatus shown in FIG.

  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. FIG. 2 is a front view of the periphery of the upper electrode and the lower electrode of the plasma processing apparatus according to the first embodiment shown in FIG. 3 to 6 are views for explaining in detail the structure of the lower electrode of the plasma processing apparatus according to the first embodiment shown in FIG. First, with reference to FIGS. 1-6, 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 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. 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 main surfaces of the upper electrode 3 and the lower electrode 4 have an area of about 600 mm × about 600 mm. The upper electrode 3 is formed with a substrate holding portion 3 a for holding the substrate 10 on the side facing the lower electrode 4. The substrate 10 has an area of about 400 mm (X direction) × about 300 mm (Y direction in FIG. 3). The upper electrode 3 is provided so as to be swingable in the X direction. 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, as shown in FIG. 2, the lower electrode 4 is integrally formed with a plurality of convex portions 4 a and a plurality of concave portions 4 b on the side facing the upper electrode 3. This makes it possible to generate high-density plasma around the convex portion 4a during film formation. Moreover, as shown in FIG. 4, the distance h from the front-end | tip part of the convex part 4a to the bottom face of the recessed part 4b is about 10 mm. As shown in FIGS. 2 and 4, the tip of the convex portion 4 a is formed so that the width decreases from the root to the tip. As a result, the electric field can be more concentrated on the tip portion having a small width of the convex portion 4a, so that higher-density plasma can be generated. Moreover, the convex part 4a is arrange | positioned so that the plasma generation area | region 20 may overlap between the adjacent convex parts 4a, as shown in FIG.4 and FIG.5. Further, a gas supply port 4 c for supplying a source gas to the plasma is provided on the convex portion 4 a of the lower electrode 4. Further, the tip 4d of the gas supply port 4c of the convex portion 4a is formed to have a curved surface shape with a radius of about 0.5 mm or less, as shown in FIG. As a result, the gas supplied from the gas supply port 4c can be retained in the vicinity of the tip of the convex portion 4a as indicated by the arrow S, so that the residence time of the source gas in the plasma generation region 20 can be increased. It becomes possible. As a result, it is possible to generate more film formation seeds, and thus it is possible to increase the film formation speed. Further, as shown in FIG. 3, the convex portions 4a are arranged at intervals of d1 (about 7 mm) and d2 (about 7 mm) in the X direction and the Y direction, respectively.

  In the first embodiment, in the recess 4b of the lower electrode 4, as shown in FIGS. 3 to 5, the unreacted gas and negative ions, malignant radicals and A gas suction port 4e for discharging products such as flakes is provided. Moreover, the recessed part 4b is arrange | positioned symmetrically with respect to the center part 30 (refer FIG. 3) of the convex part 4a. Specifically, as shown in FIG. 3, the gas suction port 4e of the recess 4b is arranged at the center of a square formed by the centers 30 of the four adjacent protrusions 4a. Accordingly, the gas suction ports 4e of the recesses 4b are also arranged at intervals of about 7 mm in the X direction and the Y direction, respectively, similarly to the projections 4a.

  As shown in FIG. 1, the vacuum chamber 2 has an exhaust port 2 a on the side, and the exhaust port 2 a is connected to the vacuum exhaust system 6 via an exhaust flow rate adjusting valve 5. The evacuation facility 6 is constituted by a turbo molecular pump (TMP) 6a and an oil rotary pump (RP) 6b. The gas supply port 4 c of the lower electrode 4 is connected to the source gas supply source 7. The gas suction port 4 e of the lower electrode 4 is connected to the vacuum exhaust equipment 8. The evacuation equipment 8 is constituted by a mechanical booster pump (MBP) 8a and an oil rotary pump (RP) 8b.

  In the first embodiment, as described above, the electric field can be concentrated on the convex portion 4a of the lower electrode 4 by providing the lower electrode 4 in which the plurality of convex portions 4a are formed in the portion facing the upper electrode 3. Therefore, high density plasma can be generated on the convex portion 4a of the lower electrode 4. Thereby, since the decomposition efficiency of the source gas can be improved, the film formation rate can be improved. In addition, a gas supply port 4 c for supplying the source gas is formed in the convex portion 4 a of the lower electrode 4, and a gas suction port 4 e for discharging the source gas is formed in the concave portion 4 b of the lower electrode 4. Thus, the gas supply port 4c and the gas suction port 4e can be uniformly arranged in the entire region of the lower electrode 4. As a result, even when a high-pressure atmosphere is provided and the gap between the upper electrode 3 and the lower electrode 4 is reduced, the unreacted gas at the central portion and the end portion of the substrate 10 is formed by the gas suction port 4e provided in the lower electrode 4. Since the product can be discharged uniformly with the same displacement, the concentration of the source gas at the center and the end of the substrate 10 can be made more uniform. Thereby, it can suppress more effectively that a film thickness and film quality become non-uniform | heterogenous.

  In the first embodiment, the plurality of convex portions 4a are arranged so that the plasma generation region 20 centered on the convex portion 4a overlaps the plasma generation region 20 centered on the adjacent convex portion 4a. As a result, the plasma generation region 20 can be disposed also in the region between the adjacent convex portions 4 a, so that the plasma generation region 20 can be disposed on the entire surface of the lower electrode 4. Thereby, since the film-forming seed | species can be produced | generated in the whole surface of the lower electrode 4, even if the convex part 4a is provided, it can suppress effectively that a film thickness and film quality become non-uniform | heterogenous.

  Further, in the first embodiment, the upper electrode 3 and the substrate 10 are provided so as to be swingable, so that the region corresponding to the convex portion 4a of the lower electrode 4 having a high plasma density due to the swinging of the upper electrode 3 and the substrate 10. Can be uniformly distributed on the surface of the substrate 10 at the time of film formation, so that even if the protrusions 4a are provided, it is possible to prevent the film thickness and film quality from becoming uneven.

  In the first embodiment, a plurality of the recesses 4b are arranged in the vicinity of the projections 4a in a plan view, and the plurality of the recesses 4b are arranged symmetrically with respect to the central portion 30 of the projections 4a. By the gas suction port 4e of the concave portion 4b arranged symmetrically with respect to the central portion 30 of the gas supply port 4c of the convex portion 4a, the unreacted gas and the product are more concentrated with respect to the gas supply port 4c of the convex portion 4a. It can be discharged uniformly. Thereby, since source gas can be supplied more uniformly by the gas supply port 4c of the convex part 4a, it can suppress that a film thickness and film quality become non-uniform | heterogenous.

  Next, a method of forming a predetermined film 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, the substrate 10 is fixed to the substrate holding portion 3 a formed on the side of the upper electrode 3 of the plasma processing apparatus 1 facing the lower electrode 4, and then connected to the exhaust port 2 a of the vacuum chamber 2. The inside of the vacuum chamber 2 is evacuated by the evacuated equipment 6 thus prepared.

  Next, as shown in FIG. 2, the source gas is supplied between the upper electrode 3 and the lower electrode 4 from the gas supply port 4c of the lower electrode 4 connected to the source gas supply source 7 (see FIG. 1). . Then, the upper electrode 3 and the substrate 10 are swung by a predetermined amount in the X direction. Thereafter, by supplying high frequency power to the lower electrode 4, plasma is generated around the convex portion 4 a of 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, between the upper electrode 3 and the lower electrode 4, in addition to the film-forming species, unreacted gas (source gas) that is not decomposed by plasma, negative ions generated by the source gas being decomposed by plasma, and malignant ions There are 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, unreacted gas, negative ions, malignant radicals, and flakes are sucked by the gas suction port 4e while supplying the source gas by the gas supply port 4c. Negative ions, malignant radicals and flakes are also discharged from the exhaust port 2a of the vacuum chamber 2 as shown in FIG.

  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.

  FIG. 7 is a diagram for explaining in detail an experiment for confirming the effect of the plasma processing apparatus according to the first embodiment shown in FIG. Next, an experiment conducted for confirming the effects relating to the film forming speed, film thickness, and film quality of the first embodiment will be described. In this confirmation experiment, the microcrystalline Si film according to Example 1 was formed on the substrate 10 using the plasma processing apparatus 1 including the lower electrode 4 provided with the convex portions 4a and the gas suction ports 4e. And while measuring the film thickness of the microcrystalline Si film | membrane by Example 1, the dispersion | variation in film thickness was computed. Further, the Raman spectrum intensity of the microcrystalline Si film according to Example 1 was measured, and the Raman intensity ratio (Ic / Ia) was calculated. The Raman intensity ratio is obtained by dividing Ic (Raman spectral intensity attributed to crystalline silicon) by Ia (Raman spectral intensity attributed to amorphous silicon). As Comparative Example 1 with respect to Example 1, a microcrystalline Si film according to Comparative Example 1 was formed on a substrate 110 using a plasma processing apparatus 101 provided with a flat surface-like lower electrode 104 having only a gas supply port 104a. Formed. And while measuring the film thickness of the microcrystal Si film | membrane by the comparative example 1, the dispersion | variation in film thickness was computed. Further, the Raman spectrum intensity of the microcrystalline Si film according to Comparative Example 1 was measured, and the Raman intensity ratio (Ic / Ia) was calculated. Hereinafter, Example 1 and Comparative Example 1 will be described in detail.

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. In addition, the distance from the front-end | tip of the convex part 4a of the lower electrode 4 to the board | substrate 10 was set to 15 mm. In Example 1, the microcrystalline Si film was formed without swinging the upper electrode 3 and the substrate 10. The conditions for forming the microcrystalline Si film according to Example 1 are shown in Table 1 below.

Referring to Table 1 above, when the microcrystalline Si film according to Example 1 was formed, the frequency, high frequency power, pressure, and substrate temperature were set to 40 MHz, 500 W, 665 Pa, and 230 ° C., respectively. Further, the raw material gas flow rates when forming the microcrystalline Si film according to Example 1 were set to SiH ₄ (2%: H ₂ dilution): 65 sccm and H ₂ : 3000 sccm. The formation time was set to 30 minutes (min).

(Comparative Example 1)
In Comparative Example 1, a microcrystalline Si film was formed on a glass substrate as the substrate 110 using the conventional plasma processing apparatus 101 shown in FIGS. Note that the distance from the lower electrode 104 to the substrate 110 was set to 15 mm. 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.

  Then, the film thickness and Raman spectrum intensity of the microcrystalline Si film according to Example 1 and Comparative Example 1 were measured. As shown in FIG. 7, the measurement points are the centers A to F of the respective areas when the substrates 10 and 110 are divided into six equal areas of about 133.3 mm × about 150 mm. These results are shown in Tables 2 and 3 below.

  Referring to Table 2 and Table 3 above, the film formation speed of Example 1 using the plasma processing apparatus 1 in which the convex portion 4a is provided on the lower electrode 4 is the plasma processing in which the surface of the lower electrode 104 is flat. It was found that the film formation rate of Comparative Example 1 using the apparatus 101 was increased by about 22.9%. Specifically, the average thickness of the microcrystalline Si film according to Comparative Example 1 is 681 nm, and the thickness of the microcrystalline Si film according to Example 1 is the average thickness of Comparative Example 1 ( 6837 nm (average value), which is about 22.9% higher than that of 681 nm. This is considered to be due to the following reasons. That is, in the plasma processing apparatus 1 used for forming the microcrystalline Si film according to the first embodiment, since the convex portion 4a is provided on the lower electrode 4, plasma is concentrated and generated around the convex portion 4a. Thereby, since the density of plasma can be made high, it is thought that the decomposition | disassembly efficiency of source gas was able to be improved. As a result, in Example 1 provided with the convex portions 4a, it is considered that the film formation rate was higher than that in Comparative Example 1 in which the surface of the lower electrode 104 was flat.

  The film thickness of the microcrystalline Si film of Example 1 using the plasma processing apparatus 1 in which the lower electrode 4 is provided with the convex portions 4a is the same as that of the plasma processing apparatus 101 in which the surface of the lower electrode 104 is flat. It was found that the uniformity was higher than the film thickness of the microcrystalline Si film of Comparative Example 1. Specifically, the standard deviation of the film thickness of the microcrystalline Si film according to Example 1 is 17.2 nm, and the standard deviation of the film thickness of the microcrystalline Si film according to Comparative Example 1 is 25.0 nm. It was. Here, the small standard deviation means that the variation is small and the uniformity is high. Therefore, the microcrystalline Si film according to Example 1 has a film thickness larger than that of the microcrystalline Si film according to Comparative Example 1. It can be said that the uniformity is high. This is considered to be due to the following reasons. That is, in the plasma processing apparatus 1 used for forming the microcrystalline Si film according to Example 1, the lower electrode 4 is provided with the gas suction port 4e for discharging negative ions, malignant radicals and flakes. 4, the gas supply port 4c and the gas suction port 4e can be arranged uniformly. As a result, the gas suction port 4e provided in the lower electrode 4 can uniformly discharge the unreacted gas and the product at the central portion and the end portion of the substrate 10, so that the central portion and the end portion of the substrate 10 The concentration of the raw material gas can be made more uniform. Thereby, it is considered that the film thickness can be more effectively suppressed.

  As shown in Tables 2 and 3, the Raman intensity ratio of Example 1 using the plasma processing apparatus 1 in which the convex portion 4a is provided on the lower electrode 4 is such that the surface of the lower electrode 104 is flat. It was found that the variation was smaller than the Raman intensity ratio of Comparative Example 1 using the plasma processing apparatus 101. Specifically, the standard deviation of the Raman intensity ratio of the microcrystalline Si film according to Example 1 is 0.420, and the standard deviation of the Raman intensity ratio of the microcrystalline Si film according to Comparative Example 1 is 0.771. Met. This is considered to be due to the following reasons. That is, in the plasma processing apparatus 1 used for forming the microcrystalline Si film according to Example 1, the lower electrode 4 is provided with the gas suction port 4e for discharging negative ions, malignant radicals and flakes. 4, the gas supply port 4c and the gas suction port 4e can be arranged uniformly. As a result, the gas suction port 4e provided in the lower electrode 4 can uniformly discharge the unreacted gas and the product at the central portion and the end portion of the substrate 10, so that the central portion and the end portion of the substrate 10 The concentration of the raw material gas can be made more uniform. For this reason, it is thought that the film quality became uniform.

  Next, an experiment conducted for confirming the effect when the upper electrode 3 and the substrate 10 are swung during the film formation of the first embodiment will be described. In this confirmation experiment, the microcrystal system according to Example 2 in which the upper electrode 3 and the substrate 10 are swung during film formation using the plasma processing apparatus 1 including the lower electrode 4 provided with the convex portions 4a and the gas suction ports 4e. A Si film was formed, and a microcrystalline Si film according to Example 3 in which the upper electrode 3 and the substrate 10 were not swung during the film formation was formed. Then, the film thickness of the microcrystalline Si film according to each of Examples 2 and 3 was measured, and the film thickness variation was calculated. Examples 2 and 3 will be described in detail below.

(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 1 according to the first embodiment shown in FIG. In addition, the distance from the front-end | tip part of the convex part 4a of the lower electrode 4 to the board | substrate 10 was set to 15 mm. In Example 2, the microcrystalline Si film was formed while swinging the upper electrode 3 and the substrate 10 in the X direction. The rocking speed and rocking width were set to 5 mm / sec and 100 mm, respectively. 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 described above.

(Example 3)
In Example 3, 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. In addition, the distance from the front-end | tip of the convex part 4a of the lower electrode 4 to the board | substrate 10 was set to 15 mm. In Example 3, the microcrystalline Si film was formed without swinging the upper electrode 3 and the substrate 10. The formation conditions of the microcrystalline Si film according to Example 3 are the same as the formation conditions of the microcrystalline Si film according to Example 1 described above.

  The film thickness of the microcrystalline Si film according to Example 2 and Example 3 was measured. Note that the measurement points are G to L shown in FIG. Note that G, I, and K are portions of the substrate 10 that face the central portions of the adjacent convex portions 4a and convex portions 4a. H, J, and L are portions of the substrate 10 that face the central portion of the convex portion 4a. These results are shown in Table 4 below.

  Referring to Table 4 above, the film thickness of Example 2 in which the upper electrode 3 and the substrate 10 were swung was higher in uniformity than the film thickness of Example 3 in which the upper electrode 3 and the substrate 10 were not swung. It has been found. Specifically, the standard deviation of the film thickness of the microcrystalline Si film according to Example 2 is 3.14 nm, and the standard deviation of the film thickness of the microcrystalline Si film according to Example 3 is 38.0 nm. It was. That is, in Example 2, since it has a small standard deviation of 1/10 or less of the standard deviation of Example 3, it can be said that the uniformity is significantly higher than that of Example 3. This is considered to be due to the following reasons. That is, in Example 2 in which the upper electrode 3 and the substrate 10 are swung, the region corresponding to the convex portion 4a of the lower electrode 4 having a high plasma density is formed at the time of film formation by the rocking of the upper electrode 3 and the substrate 10. It is considered that the film thickness can be made uniform as compared with Example 3 in which the upper electrode 3 and the substrate 10 are not swung.

(Second Embodiment)
9 to 11 are views for explaining in detail the structure of the lower electrode of the plasma processing apparatus according to the second embodiment of the present invention. With reference to FIGS. 4 and 9 to 11, in the second embodiment, a plasma processing apparatus in which an insulating member 14 is disposed in the recess 4 b of the lower electrode 4 will be described, unlike the first embodiment.

  That is, in the plasma processing apparatus according to the second embodiment, as shown in FIGS. 9 to 11, the insulating member 14 made of alumina, quartz, or the like is disposed in the recess 4 b of the lower electrode 4. The insulating member 14 is formed with a gas flow path 14a (see FIG. 11) for discharging gas. The gas flow path 14a is formed so as to be continuous with the gas suction port 4e provided in the recess 4b. Further, the upper surface of the insulating member 14 is located at a position slightly lower than the upper surface of the convex portion 4 a of the lower electrode 4.

  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, by disposing the insulating member 14 in which the gas flow path 14a is formed in the recess 4b of the lower electrode 4, the gas passes through the recess 4b and is discharged from the gas suction port 4e. In this case, since the area of the portion through which the gas passes in the recess 4b can be reduced by the gas flow path 14a, the flow rate of the exhaust gas on the upper surface of the lower electrode 4 can be increased. Thereby, it can suppress that flakes etc. adhere to the crevice 4b. When the insulating member 14 is not disposed in the electrode recess 4b as in the first embodiment, flakes f as shown in FIG. 4 are likely to adhere to the recess 4b. This is considered to be due to the following reason. That is, in the lower electrode 4 shown in FIG. 4, since the area of the recess 4b is larger than the area of the gas suction port 4e, the gas in the recess 4b is exhausted when the gas is exhausted by the gas suction port 4e provided in the recess 4b. The flow velocity of Thereby, it is considered that flakes f and the like are likely to adhere to the surface of the recess 4 b of the lower electrode 4.

  Further, in the second embodiment, by disposing the insulating member 14 made of an insulating material in the concave portion 4b, it is possible to suppress the dispersion of the electric field concentrated on the convex portion 4a of the lower electrode 4 made of metal. Even if the insulating member 14 is provided, it is possible to suppress a decrease in plasma density.

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

  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, the example in which the gas supply port is provided in the convex portion and the gas suction port is provided in the concave portion is shown. However, the present invention is not limited thereto, and the first embodiment shown in FIG. As in the first modification, the gas supply port 24 c may be provided in the concave portion 24 b of the lower electrode 24, and the gas suction port 24 e may be provided in the convex portion 24 a of the lower electrode 24.

  Moreover, in the said 1st Embodiment, although the convex part was each arrange | positioned at a space | interval of about 7 mm in a X direction and a Y direction, the example which has arrange | positioned a recessed part at a space | interval of about 7 mm in a X direction and a Y direction was shown, respectively. Is not limited to this, and a convex portion and a concave portion as in the second modified example of the first embodiment shown in FIGS. 13 and 14 or the third modified example of the first embodiment shown in FIGS. 15 and 16. May be arranged. Specifically, in the second modification of the first embodiment, as shown in FIGS. 13 and 14, the protrusions 34a and the recesses 34b of the lower electrode 34 extend in the Y direction along the main surface of the substrate. They are formed at a predetermined interval in the X direction. A gas supply port 34c is provided in the convex portion 34a with a predetermined interval in the Y direction, and a gas suction port 34e is provided in the concave portion 34b with a predetermined interval in the Y direction. In this case, since the gas supply port 34c and the gas suction port 34e can be disposed along the Y direction, respectively, the uniformity of the film thickness and film quality along the Y direction can be improved. Further, in the third modification of the first embodiment, as shown in FIGS. 15 and 16, the protrusion 44a and the recess 44b of the lower electrode 44 extend in the X direction so as to extend in the Y direction along the main surface of the substrate. They are formed at a predetermined interval. The gas supply port 44c is formed in the convex portion 44a in a slit shape extending in the Y direction, and the gas suction port 44e is formed in the concave portion 44b in a slit shape extending in the Y direction. In this case, since the gas supply port 44c and the gas suction port 44e can be arranged so as to extend in the Y direction, respectively, the uniformity of the film thickness and film quality along the Y direction can be further improved.

  In the first embodiment, the gas supply port is configured by the hole provided in the convex portion of the lower electrode, and the gas suction port is configured by the hole provided in the concave portion. Not only, but as in the fourth modification of the first embodiment shown in FIG. 17, the convex portions 54a and the concave portions 54b of the lower electrode 54 are formed into a mesh shape by a mold, and the mesh-shaped convex portions 54a and A gas supply port 54c and a gas suction port 54e made of pipe-shaped nozzles provided separately may be embedded in the recesses 54b, respectively.

  In the above-described embodiment, the upper electrode and the substrate are swung along the X direction. However, the present invention is not limited to this, and the upper electrode and the substrate are swung along the Y direction other than the X direction. You may move.

  In the above embodiment, the example in which the swing width of the upper electrode and the substrate is set to 100 mm is shown. However, the present invention is not limited to this, and the swing width of the upper electrode and the substrate is set to other values. Also good. However, it is desirable to set the swing width of the upper electrode and the substrate to be equal to or greater than the pitch of the convex portions (about 7 mm).

3 Upper electrode 4, 24, 34, 44, 54 Lower electrode 4a, 24a, 34a, 44a, 54a Convex part 4b, 24b, 34b, 44b, 54b Concave part 4c, 24c, 34c, 44c, 54c Gas supply port 4e, 24e , 34e, 44e, 54e Gas suction port 10 Substrate 20 Plasma generation region

Claims (7)

A first electrode capable of holding a substrate;
A second electrode provided with a plurality of convex portions and a plurality of concave portions formed in a portion facing the first electrode and facing the first electrode;
A gas supply port for supplying gas is formed in one of the convex portion and the concave portion of the second electrode, and the gas is supplied to the other of the convex portion and the concave portion of the second electrode. A gas suction port is formed for discharge,
The recesses are arranged in the vicinity of the projections in a plan view, and the plurality of recesses are arranged symmetrically with respect to the center of the projections,
A plasma processing apparatus, wherein an insulating member is disposed in the recess. The plasma processing apparatus according to claim 1 , wherein an upper surface of the insulating member is disposed at a position lower than an upper surface of the convex portion of the second electrode. The convex portion and the concave portion is formed so as to extend in a predetermined direction along the main surface of the substrate, are disposed at predetermined intervals in a direction crossing the predetermined direction, according to claim 1 Or the plasma processing apparatus of 2. The plasma processing apparatus according to claim 1 , wherein the gas supply port is formed in a slit shape so as to extend in the predetermined direction along the main surface of the substrate. The plasma according to any one of claims 1 to 4 , wherein a width of a tip portion on the first electrode side of the convex portion of the second electrode is smaller than a width of a root portion of the convex portion of the second electrode. Processing equipment. The plasma processing apparatus according to claim 1 , wherein a gas flow path for discharging gas is formed in the insulating member. The plasma processing apparatus according to claim 1 , wherein the substrate held by the first electrode is configured to be swingable.

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