JP2004228102A - Plasma treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable charged particulates to be effectively removed in a plasma applied apparatus. <P>SOLUTION: The inside of a vacuum vessel is kept vacuum in a plasma CVD apparatus, gas is introduced into the vacuum vessel for treating semiconductors, and a positive voltage is applied to the conductor of an NFP collector. When a high-frequency power is applied from a high-frequency power source 120 to a lower electrode 32, particulates are generated and charged with negative static electricity through an electron sheath over the lower electrode 32. The particulates charged with negative static electricity are guided by particulate guide grooves 320-1 to 320-8 and furthermore attracted to the conductor of the NFP collector 40 so as to be removed from above the lower electrode 32. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma processing apparatus provided with a particle attracting device for attracting charged particles generated in a processing chamber for processing a substrate to be processed.
[0002]
[Prior art]
For example, Patent Literature 1 discloses a method of removing charged fine particles generated in a vacuum vessel by forming a groove, a projection, or a tapered portion in an electrode in a plasma CVD (Chemical Vapor Deposition) apparatus or the like.
Also, for example, Patent Document 2 discloses a method of removing charged fine particles using an electrode to which a voltage having a polarity opposite to that of the fine particles is applied in a similar device.
[0003]
[Patent Document 1] JP-A-5-74737 [Patent Document 2] International Publication WO 01/01467 A1
[0004]
[Problems to be solved by the invention]
The present invention has been made on the premise of the above-described conventional technology, and has as its object to provide a plasma processing apparatus capable of effectively removing charged fine particles generated during processing of a substrate.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a plasma processing apparatus according to the present invention includes an upper electrode disposed substantially horizontally, and a lower electrode disposed substantially parallel to the upper electrode. A plasma generating means for generating plasma between the electrodes and charging at least the lower electrode to a first polarity; and a plasma generating means formed on the lower electrode, wherein the first electrode is formed on the lower electrode. A guiding groove for guiding particles charged to a polarity of, and a particle attracting means disposed at an end of the guiding groove and for attracting the particles charged to the first polarity guided to the guiding groove, The particle attracting means has a third electrode charged to a second polarity different from the first polarity, or a suction means for sucking particles attracted to the third electrode and the third electrode. .
[0006]
Preferably, the guide groove formed in the lower electrode is formed so as to increase in width toward the near end of the particle attracting means, and has a depth that increases toward the proximal end of the particle attracting means. It is formed so that it becomes wider toward the near end of the particle attracting means and becomes deeper toward the near end of the particle attracting means.
[0007]
Preferably, the guide groove is filled with an insulator.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
[Background of the present invention]
Prior to the description of the embodiment, first, the background that led to the present invention will be described to facilitate understanding of the present invention.
[0009]
[PECVD]
FIG. 1 is a diagram illustrating the configuration of a plasma CVD apparatus 1 to which fine particle removal according to the present invention is applied.
Plasma enhanced chemical vapor deposition (PECVD) is very commonly used in the field of semiconductor manufacturing for etching processes, thin film deposition, and the like.
[0010]
As shown in FIG. 1, a plasma CVD apparatus 1 for performing PECVD includes a vacuum vessel 100 (indicated by a dotted line in FIG. 1), and a pair of two pieces vertically arranged in the vacuum vessel 100. , And a high-frequency power supply (described later with reference to FIG. 4 and the like) for supplying high-frequency power to these plate-like electrodes.
The lower electrode 30 is attached to the vacuum vessel 100 by an attachment stay 102, and a semiconductor wafer to be processed is placed on a susceptor that also serves as the lower electrode 30, and high frequency power is applied to the lower electrode 30, The electrode 20 is set to the ground voltage (0 V).
[0011]
The gas introduced into the vacuum vessel 100 is turned into plasma by high-frequency power applied between the two plate-like electrodes (the upper electrode 20 and the lower electrode 30), turned into a reactive gas, and deposited on the semiconductor wafer. Thus, a film constituting the semiconductor device is formed.
However, in addition to forming a film on the semiconductor wafer, the reactive gas adheres to a wall surface inside the vacuum vessel 100 or reacts with another gas phase component in the vacuum vessel 100 to have a diameter of 1/10. It becomes fine particles of micron to several tens of microns.
Such fine particles must adhere to the semiconductor wafer and have a bad influence on the semiconductor manufacturing process.
[0012]
[Particle removal method]
When a high frequency is applied between the two plate electrodes (upper electrode 20 and lower electrode 30) and plasma is generated, an electron sheath is formed on the lower electrode.
When the particles approach the lower electrode, the particles receive electrons from the electron sheath and are charged to a negative polarity.
The following two examples can be given as examples of the method of removing the charged fine particles.
[0013]
[Removal Method for Forming Grooves and the Like in Electrode (First Particle Removal Method)]
FIG. 2 shows the electrostatic potential pattern 22 between the upper electrode 20 and the lower electrode 30 and the lower electrode (inside) 32 formed in the plasma CVD apparatus 1 (FIG. 1) to which the removal of fine particles according to the present invention is applied. FIG. 8 is a diagram illustrating first fine particle guiding grooves 320-1 to 320-8.
Here, as shown in FIG. 2, when the inside of the lower electrode 30 shown in FIG. 1 is shown, the lower electrode (inside) 32 may be described.
However, for simplicity of illustration, in FIG. 2, one or more (for example, eight) first particle guiding grooves 320-1 to 320-8 formed in the lower electrode (inside) 32 are: Only three are shown.
In the following, when any one of a plurality of constituent parts such as the fine particle guiding grooves 320-1 to 320-8 is shown without being specified, it may be simply abbreviated as the fine particle guiding groove 320.
[0014]
For example, as disclosed in Patent Document 1, when the fine particle guiding groove 320 is formed on the lower electrode (inside) 32, the electrostatic potential between the upper electrode 20 and the lower electrode (inside) 32 becomes 2 is as illustrated as the electrostatic potential pattern 22.
As described above, since the fine particles are negatively charged by the electron sheath, they float above the electron sheath and gather in a portion where the potential of the electrostatic potential pattern 22 is high.
Since the surface of the electron sheath lowers along the shape of the fine particle guiding groove 320, the potential on the fine particle guiding groove 320 increases.
Therefore, by forming the fine particle guiding groove 320, negatively charged fine particles can be guided to the fine particle guiding groove 320.
[0015]
Also, as the depth of the fine particle guiding groove 320 increases, and as the width of the fine particle guiding groove 320 increases, the surface of the electronic sheath on the fine particle guiding groove 320 decreases, and the potential of that portion increases.
Therefore, the fine particles are guided in a desired direction by forming the fine particle guiding grooves 320 so that the depth gradually increases and the width gradually increases as the fine particles proceed in the direction in which the fine particles are to be guided. can do.
[0016]
[Removal method using electrode to which positive voltage is applied (second removal method)]
As described above, the fine particles on the lower electrode (inside) 32 are negatively charged, and are attracted to the electrode to which a positive voltage is applied.
For example, as disclosed in Patent Document 2 described above, the method of inducing fine particles using an electrode to which a positive voltage is applied and discharging the collected fine particles also allows fine particles on the lower electrode (inside) 32 to be removed. Can be removed.
The fine particle removal according to the present invention is designed so that the fine particles on the lower electrode (inside) 32 can be more effectively removed by using the first and second removal methods in combination.
[0017]
[Embodiment]
Hereinafter, embodiments of the present invention will be described.
FIG. 3 shows a lower electrode (internal) 32 used in the plasma CVD apparatus 1 (FIG. 1) to which fine particles removal according to the present invention is applied, and one or more fine particle guiding grooves formed in the lower electrode (internal) 32. FIG. 3 is a perspective view showing negatively charged fine particle (NFP) collectors 40 arranged opposite to each other.
FIG. 4 is a diagram showing connections between the upper electrode 20, the lower electrode (internal) 32, and the first NFP collector 40 shown in FIGS.
[0018]
FIG. 5 is a perspective view illustrating the first NFP collector 40 shown in FIG.
FIG. 6 is a diagram showing a configuration of the first NFP collector 40 shown in FIG.
Hereinafter, unless otherwise specified, a case where eight fine particle guiding grooves 320-1 to 320-8 are formed in the lower electrode (inside) 32 will be described as a specific example.
[0019]
As shown in FIGS. 3 and 4, in the lower electrode (inside) 32, fine particle guiding grooves 320-1 to 320-8 are provided in the center thereof, and have a circular (other shape, for example, a square) semiconductor provided at the center thereof. It is formed radially from the wafer mounting part 324.
The lower electrode 30 (lower electrode (internal) 32) is connected to a high-frequency power supply 120 via a capacitor 122 as shown in FIGS.
The upper electrode 20 is also connected to a ground potential, as shown in FIGS.
[0020]
The end of each of the semiconductor wafer mounting portions 324 is aligned with each of the openings 300-1 to 300-8 provided around the lower electrode 30 shown in FIG.
The openings 404 (FIG. 6) of the first NFP collectors 40-1 to 40-8 (FIGS. 3 and 5) respectively pass through the openings 300-1 to 300-8 (FIG. 1) of the lower electrode 30. Thus, the fine particle guiding grooves 320-1 to 320-8 are attached at positions facing the respective ends on the outer periphery of the lower electrode (inside) 32.
[0021]
As shown in FIG. 6, the NFP collector 40 has a configuration in which the outside of a cylindrical conductor 402 is covered with an insulator 400 such as ceramic.
As shown in FIGS. 4 to 6, a positive voltage is applied to the conductor 402 of the NFP collector 40 from a DC power supply via an electric wire 412.
That is, the plasma CVD apparatus 1 has a configuration in which NFP collectors 40-1 to 40-8 and a DC power supply 124 for applying a positive voltage thereto are added to a general semiconductor processing apparatus that performs processing on a semiconductor by the PECVD method. Take.
[0022]
In the plasma CVD apparatus 1, the inside of the vacuum vessel 100 is evacuated, a gas used for semiconductor processing is introduced, and a positive voltage is applied to the conductor 402 of the NFP collector 40.
When high-frequency power is applied from the high-frequency power supply 120 to the lower electrode (inside) 32, as described above, fine particles are generated and negatively charged by an electronic sheath (not shown) on the lower electrode (inside) 32.
The negatively charged fine particles are guided by the fine particle guiding grooves 320-1 to 320-8, further attracted to the conductor 402 of the NFP collector 40, and removed from the lower electrode (inside) 32.
[0023]
[Modification]
Hereinafter, a modified example of the plasma CVD apparatus 1 will be described.
[0024]
[Modified Example of Fine Particle Guide Groove 320]
First, a modified example of the fine particle guiding groove 320 will be described.
FIG. 7 is a diagram showing a first modification (second fine particle guiding groove 322) of the first fine particle guiding groove 320 shown in FIGS.
As described above, if the fine particle guiding groove 320 is formed in a fan-like shape in which the width becomes wider as it goes closer to the periphery of the lower electrode (inside) 32, the semiconductor wafer mounting portion 324 to the lower electrode (inside) 32 Fine particles are guided toward the outer periphery.
Accordingly, as shown in FIG. 7, when the fine particle guiding groove 320 on the lower electrode (inside) 32 is replaced with a fan-shaped fine particle guiding groove 322, the fine particle guiding groove 322 is formed in the opening 404 and the conductor 402 of the NFP collector 40. Can be induced more efficiently.
[0025]
FIG. 8 is a diagram showing a second modification (third particle guiding groove 330) of the first particle guiding groove 320 shown in FIGS.
Further, as described above, if the fine particle guiding groove 320 is formed so as to be deeper as it goes closer to the periphery of the lower electrode (inside) 32, it goes from the semiconductor wafer mounting portion 324 to the outer periphery of the lower electrode (inside) 32. In the direction, the fine particles are guided.
Therefore, when the first fine particle guiding groove 320 is replaced with the third fine particle guiding groove 330 shown in FIG. 8, fine particles can be more efficiently guided to the opening 404 of the NFP collector 40 and the conductor 402. it can.
Note that the fine particle guiding groove on the lower electrode (inside) 32 may be formed in a shape combining the shapes of the second and third fine particle guiding grooves 322 and 326 shown in FIGS. 7 and 8.
[0026]
FIG. 9 is a view showing the first fine particle guiding groove 320 filled with an insulator.
As shown in FIG. 9, filling insulating materials 328-1 to 328-8 such as ceramics are provided in the first fine particle guiding grooves 320-1 to 320-8 shown in FIGS. Fill so that 32 is flat.
As described above, even if the fine particle guiding grooves 320-1 to 320-8 filled with the insulator are used, the electrostatic potential pattern 22 formed by the fine particle guiding grooves 320-1 to 320-8 is hardly affected.
[0027]
Therefore, the fine particle guiding grooves 320-1 to 320-8 filled with the insulator can also guide the fine particles, similarly to the fine particle guiding grooves 320-1 to 320-8 not filled with the insulator. .
Further, by filling the fine particle guiding grooves 320-1 to 320-8 with the filling insulating materials 328-1 to 328-8, it is possible to prevent the fine particles from accumulating in these grooves.
[0028]
[Modification of NFP collector]
FIGS. 10 to 12 are diagrams showing first to third modified examples (second to fourth NFP collectors 42, 44, 46) of the first NFP collector 40 shown in FIGS. . In the NFP collector 40, an electrostatic barrier may be formed in the opening 404 by the ceramic insulator 400, and the performance of the NFP collector 40 for removing fine particles may be reduced.
In order to eliminate the influence of such an electrostatic barrier, the conductor 402 of the first NFP collector 40 is replaced by a conductor 422 protruding from the insulator 400, and the second NFP shown in FIG. The collector 42 is used.
In the plasma CVD apparatus 1, by replacing the first NFP collector 40 with the second NFP collector 42, fine particles of the lower electrode (inside) 32 can be more efficiently removed.
[0029]
Further, as shown in FIG. 11, an exhaust port 446 is provided at an end opposite to the opening 424 of the second NFP collector 42 so that the fine particles sucked to the conductor 422 are exhausted by the plasma CVD apparatus 1. Using a system (not shown), a third NFP collector 44 that discharges outside the vacuum vessel 100 can be provided.
In the plasma CVD apparatus 1, by replacing the first and second NFP collectors 40 and 42 with the third NFP collector 44, the fine particles of the lower electrode (inside) 32 can be more efficiently removed. .
The same effect can be obtained by adding an exhaust port 446 to the second NFP collector 42.
[0030]
FIG. 13 is a cross-sectional view of the fourth NFP collector 46 shown in FIG.
As shown in FIG. 12, the main body 466 of the fourth NFP collector 46 is disposed around the lower electrode 30 (lower electrode (inside) 32).
The main body 468 of the fourth NFP collector 46 has a configuration in which a conductor 462 is covered with an insulator 460, as shown in FIG.
Further, an exhaust pipe 470 for exhausting from the inside of the conductor 462 is added to the main body 468, and the exhaust pipe 470 is located at the opening 300-i (i = 1 to 8 in the example shown in FIG. 3 and the like) of the lower electrode 30. An aligned opening 464-i is provided.
[0031]
The conductor 462 of the NFP collector 46 sucks the fine particles on the lower electrode (inside) 32 through the openings 300 and 464, and the fine particles sucked by the conductor 462 are discharged from the exhaust pipe 470 to the plasma CVD apparatus. The gas is exhausted to the outside of the vacuum vessel 100 by an exhaust system (not shown).
Even if the fourth NFP collector 46 shown in FIGS. 12 and 13 is used instead of the second or third NFP collectors 42 and 44, the same effect as the second or third NFP collectors 42 and 44 is obtained. Obtainable.
[0032]
[Others]
FIG. 14 is a diagram illustrating a lower electrode (inside) 32 in which four fine particle guiding grooves 320-1 to 320-4 are formed.
The number of the fine particle guiding grooves 320 may be one or more.
The number of the fine particle guiding grooves 320 may be, for example, four as shown in FIG. 14, depending on the cost of the plasma CVD apparatus 1, the size of the lower electrode (inside) 32, the amount of generated fine particles, and the like. .
[0033]
【The invention's effect】
As described above, according to the fine plasma processing apparatus of the present invention, charged fine particles generated during processing of a substrate can be effectively removed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a plasma CVD apparatus to which fine particles removal according to the present invention is applied.
FIG. 2 is a diagram showing an electrostatic potential pattern between an upper electrode and a lower electrode in a plasma CVD apparatus (FIG. 1) to which the removal of fine particles according to the present invention is applied, and first fine particles formed on the lower electrode (inside). It is a figure which illustrates a guide groove.
FIG. 3 faces a lower electrode (inside) used in a plasma CVD apparatus (FIG. 1) to which fine particles removal is applied according to the present invention, and one or more fine particle guiding grooves formed in the lower electrode (inside). FIG. 4 is a perspective view showing a negatively charged fine particle (NFP) collector disposed as a negative electrode;
FIG. 4 is a diagram showing a connection between an upper electrode, a lower electrode (inside) and a first NFP collector shown in FIGS. 1 to 3, and a high-frequency power supply and a DC power supply.
FIG. 5 is a perspective view illustrating a first NFP collector illustrated in FIG. 3;
FIG. 6 is a diagram showing a configuration of a first NFP collector shown in FIG.
FIG. 7 is a view showing a first modification (second fine particle guiding groove) of the first fine particle guiding groove shown in FIGS. 2 to 4;
FIG. 8 is a view showing a second modification (third particle guiding groove) of the first particle guiding groove shown in FIGS. 2 to 4;
FIG. 9 is a diagram showing a first fine particle guiding groove filled with an insulator.
FIG. 10 is a diagram showing a first modification (second NFP collector) of the first NFP collector shown in FIGS. 3 to 6;
FIG. 11 is a diagram showing a second modification (third NFP collector) of the first NFP collector shown in FIGS. 3 to 6;
FIG. 12 is a diagram showing a third modification (fourth NFP collector) of the first NFP collector shown in FIGS. 3 to 6;
FIG. 13 is a cross-sectional view of the fourth NFP collector shown in FIG.
FIG. 14 is a diagram illustrating a lower electrode (inside) in which four fine particle guiding grooves are formed.
[Explanation of symbols]
1 ... plasma CVD apparatus
100 ... vacuum container,
102 ... mounting stay,
120 ... high frequency power supply,
122: condenser,
124 DC power supply,
20 top electrode,
22 ... electrostatic potential pattern,
30, 32 ... lower electrode,
300 ... opening,
320, 322, 326, 330...
324... Semiconductor wafer mounting part,
328 ... filled insulating material,
40, 42, 44, 46 ... NFP collector,
400, 460... Insulator
402, 422, 462 ... conductor,
404, 424, 464 ... opening,
446 ... exhaust port,
412 ... electric wire,
466: body,
470 ... exhaust pipe,

Claims (3)

A plasma is generated between an upper electrode disposed substantially horizontally and a lower electrode disposed substantially parallel to and opposed to the upper electrode, and at least the lower electrode Plasma generating means for charging the first polarity to a first polarity;
A guide groove formed on the lower electrode, for guiding particles charged to the first polarity on the lower electrode;
A particle attracting means disposed at an end of the guide groove, for attracting the particles charged to the first polarity guided to the guide groove,
The particle attracting means,
A plasma processing apparatus comprising: a third electrode charged to a second polarity different from the first polarity; or a suction unit for suctioning the third electrode and particles attracted to the third electrode. The guiding groove formed in the lower electrode,
Formed so as to increase in width toward the near end of the particle attracting means,
It is formed so that the depth increases toward the near end of the particle attracting means, or is wider toward the near end of the particle attracting means, and has a depth toward the near end of the particle attracting means. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is formed so as to be deeper. The plasma processing apparatus according to claim 1, wherein the guide groove is filled with an insulator.

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