JP4212409B2 - Plasma processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus including a particle attracting apparatus that attracts charged particles generated in a processing chamber for processing a substrate to be processed.
[0002]
[Prior art]
For example, Patent Document 1 discloses a method for removing charged fine particles generated in a vacuum vessel by forming grooves, protrusions, or tapered portions on electrodes in a plasma CVD (Chemical Vapore Doposition) apparatus or the like.
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 apparatus.
[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 prior art, and an object thereof is to provide a plasma processing apparatus capable of effectively removing charged fine particles generated during processing on a substrate.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a plasma processing apparatus according to the present invention comprises an upper electrode disposed substantially horizontally and a lower side disposed substantially parallel to the upper electrode. Plasma generating means for generating plasma with the first electrode and charging at least the lower electrode to the first polarity, and formed on the lower electrode, on the lower electrode, the first electrode A guide groove for inducing particles charged to the polarity of, and a particle attracting means disposed at an end of the guide groove for attracting the particles charged to the first polarity induced in the guide groove, The particle attracting means includes 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 that the width becomes wider toward the near end of the particle attracting means, and the depth increases toward the near end of the particle attracting means. Or formed so that the width increases toward the near end of the particle attracting means and the depth increases toward the near end of the particle attracting means.
[0007]
Preferably, the guide groove is filled with an insulator.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
[Background of the present invention]
In order to help understanding of the present invention, prior to the description of the embodiment, first, the background of the present invention will be described.
[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 that performs PECVD includes a vacuum vessel 100 (shown by a dotted line in FIG. 1), and a set of two pieces arranged in parallel in the vacuum vessel 100 in the vertical direction. Plate electrodes (upper electrode 20 and lower electrode 30), and a high frequency power source (which will be described later with reference to FIG. 4) and the like for supplying high frequency power to these plate 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 also serving as the lower electrode 30, and high-frequency power is applied to the lower electrode 30 to The electrode 20 is set to a ground voltage (0 V).
[0011]
The gas introduced into the vacuum vessel 100 is turned into plasma by high-frequency power applied between these two plate-like electrodes (the upper electrode 20 and the lower electrode 30), and is deposited on the semiconductor wafer. Then, a film constituting the semiconductor device is formed.
However, this reactive gas forms a film on the semiconductor wafer, adheres to the inner wall surface of the vacuum vessel 100, or reacts with other gas phase components in the vacuum vessel 100 to have a diameter of 1/10. It becomes microparticles of micron to several tens of microns.
Such particulates must adhere to the semiconductor wafer and have a negative impact on the semiconductor manufacturing process and must be removed from the vacuum vessel 100.
[0012]
[Particle removal method]
The fine particles are charged with a negative polarity in the plasma space.
Examples of the method for removing the charged fine particles can include the following two.
[0013]
[Removal Method for Forming Grooves on Electrode (First Fine Particle Removal Method)]
FIG. 2 is formed on the electrostatic potential pattern 22 between the upper electrode 20 and the lower electrode 30 and the lower electrode (inside) 32 in the plasma CVD apparatus 1 (FIG. 1) to which fine particle removal according to the present invention is applied. It is a figure which illustrates the 1st microparticle guidance 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, it may be referred to as a lower electrode (inside) 32.
However, for simplification of illustration, in FIG. 2, one or more (for example, eight) first particle guide grooves 320-1 to 320-8 formed in the lower electrode (inside) 32 and openings thereof. Only three of the parts 300-1 to 300-8 are shown.
Hereinafter, in the case where any one of a plurality of constituent parts such as the fine particle guiding grooves 320-1 to 320-8 is not specified, they may be simply abbreviated as the fine particle guiding grooves 320.
[0014]
For example, as disclosed in Patent Document 1 above, when the particle guide groove 320 is formed on the lower electrode (inside) 32, the electrostatic potential between the upper electrode 20 and the lower electrode (inside) 32 is as shown in FIG. 2 is as exemplified as the electrostatic potential pattern 22.
As described above, since the fine particles are negatively charged by the electron sheath, the fine particles float above the electron sheath and gather at a portion where the potential of the electrostatic potential pattern 22 is high.
Since the surface of the electron sheath is lowered along the shape of the particle guide groove 320, the potential on the particle guide groove 320 is increased.
Therefore, by forming the particle guide groove 320, negatively charged particles can be induced in the particle guide groove 320.
[0015]
Further, as the particle guide groove 320 becomes deeper and the width of the particle guide groove 320 becomes wider, the surface of the electron sheath on the particle guide groove 320 decreases and the potential of the portion increases.
Accordingly, the fine particle guide groove 320 is formed so that the depth gradually increases and the width gradually increases as the particle proceeds in the direction to be guided, thereby guiding and removing the fine particle in a desired direction. can do.
[0016]
[Removal Method Using Electrode Applied with Positive Voltage (Second Removal Method)]
As described so far, 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 the above-mentioned Patent Document 2, fine particles on the lower electrode (inside) 32 can also be obtained by inducing fine particles using an electrode to which a positive voltage is applied and discharging the collected fine particles. Can be removed.
The fine particle removal according to the present invention is devised 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]
Embodiments of the present invention will be described below.
FIG. 3 shows a lower electrode (inside) 32 used in the plasma CVD apparatus 1 (FIG. 1) to which fine particle removal according to the present invention is applied, and one or more fine particle guiding grooves formed in the lower electrode (inside) 32. 320 is a perspective view showing negatively charged fine particle (NFP) collectors 40 arranged to face each of 320. FIG.
FIG. 4 is a diagram showing connections between the upper electrode 20, the lower electrode (inside) 32 and the first NFP collector 40 shown in FIGS. 1 to 3, and the high-frequency power source 120 and the DC power source 124.
[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 specific example is a case where eight fine particle guiding grooves 320-1 to 320-8 are formed in the lower electrode (inside) 32.
[0019]
As shown in FIGS. 3 and 4, the lower electrode (inside) 32 has a circular (other shape, for example, a quadrangle) semiconductor in which fine particle guiding grooves 320-1 to 320-8 are provided at the center. It is formed radially from the wafer mounting portion 324.
As shown in FIGS. 2 and 4, the lower electrode 30 (lower electrode (inside) 32) is connected to a high-frequency power source 120 through a capacitor 122 and supplied with high-frequency power.
Similarly, as shown in FIGS. 2 and 4, the upper electrode 20 is connected to the ground potential.
[0020]
Each end of the semiconductor wafer mounting portion 324 is aligned with each of the openings 300-1 to 300-8 provided around the lower electrode 30 shown in FIG.
Each of the openings 404 (FIG. 6) of the first NFP collectors 40-1 to 40-8 (FIGS. 3 and 5) passes through the openings 300-1 to 300-8 (FIG. 1) of the lower electrode 30, respectively. The particle guide grooves 320-1 to 320-8 are attached to 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 the electric wire 412.
That is, the plasma CVD apparatus 1 is configured by adding a NFP collector 40-1 to 40-8 and a DC power source 124 for applying a positive voltage thereto to a general semiconductor processing apparatus that performs processing on a semiconductor by PECVD. 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 source 120 to the lower electrode (inside) 32, fine particles are generated as described above, and are negatively charged by an electron 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]
[Semiconductor Manufacturing Method Using Plasma CVD Apparatus 1]
Here, the outline of the semiconductor manufacturing method by the plasma CVD apparatus 1 demonstrated with reference to FIGS. 1-7 is demonstrated.
The semiconductor wafer 14 is transferred into the vacuum container 100 by a semiconductor transfer device (not shown) and placed on the lower electrode 30.
In this state, the gas in the vacuum vessel 100 is exhausted.
After the gas in the vacuum container 100 is exhausted, the reaction gas is supplied into the vacuum container 100, and the upper electrode disposed in the vacuum container 100 while the reaction gas is discharged from the vacuum container 100. A high frequency power is applied between the 20 and the lower electrode 30 by the high frequency power source 120 to cause plasma discharge.
With this plasma, the substrate placed on the lower electrode 30 is subjected to a CVD process.
[0024]
In the plasma CVD apparatus 1, a plasma etching process can be performed in addition to the plasma CVD process.
In plasma processing such as CVD processing or etching processing, the particles are guided to the outer periphery of the semiconductor wafer 14 by the particle guide grooves 320-1 to 320-8 provided in the lower electrode 30.
As described above, the fine particles guided to the outer periphery of the semiconductor wafer 14 are provided around the openings 300-1 to 300-8 of the fine particle guide grooves 320-1 to 320-8, and the first potential to which a positive potential is applied. Of the NFP collectors 40-1 to 40-8.
[0025]
Next, the vacuum vessel 100 is evacuated, and the reaction gas therein is removed.
Further, an inert gas such as nitrogen gas is introduced into the vacuum vessel 100, and the inside thereof is returned to a predetermined pressure.
In this state, the semiconductor wafer 14 placed on the lower electrode 30 is carried out of the vacuum container 100 by a substrate transfer device (not shown).
A semiconductor device is manufactured by the plasma CVD apparatus 1 by the procedure as described above.
[0026]
[Modification]
Hereinafter, modified examples of the plasma CVD apparatus 1 will be described.
[0027]
[Modification of Fine Particle Guidance Groove 320]
First, a modification of the fine particle guiding groove 320 will be described.
FIG. 7 is a view showing a first modification (second fine particle guiding groove 322) of the first fine particle guiding groove 320 shown in FIGS.
As described above, when the fine particle guide groove 320 is formed in a fan-shaped shape that becomes wider as it goes to the periphery of the lower electrode (inside) 32, the semiconductor wafer mounting portion 324 leads to the lower electrode (inside) 32. Fine particles are guided in a direction toward the outer periphery.
Accordingly, as shown in FIG. 7, when the particle guide groove 320 on the lower electrode (inside) 32 is replaced with a fan-shaped particle guide groove 322, the opening 404 and the conductor 402 of the NFP collector 40 are not exposed to the particles. Can be induced more efficiently.
[0028]
FIG. 8 is a view showing a second modification (third fine particle guiding groove 330) of the first fine particle guiding groove 320 shown in FIGS.
Further, as described above, when the fine particle guiding groove 320 is formed so as to go deeper as it goes to the periphery of the lower electrode (inside) 32, the semiconductor wafer mounting portion 324 goes to the outer periphery of the lower electrode (inside) 32. In the direction, fine particles are induced.
Therefore, when the first particle guide groove 320 is replaced with the third particle guide groove 330 shown in FIG. 8, the particles can be more efficiently guided to the opening 404 and the conductor 402 of the NFP collector 40. it can.
It is also possible to form the particle guide groove on the lower electrode (inside) 32 in a combination of the shapes of the second and third particle guide grooves 322 and 326 shown in FIGS.
[0029]
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 placed in the first particle guide grooves 320-1 to 320-8 shown in FIGS. Fill so that 32 is flat.
Thus, 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.
[0030]
Accordingly, the fine particle guide grooves 320-1 to 320-8 filled with the insulator can also guide the fine particles, similarly to the fine particle guide 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 being accumulated in these grooves.
[0031]
[Modification of NFP collector]
10 to 12 are diagrams showing first to third modified examples (second to fourth NFP collectors 42, 44, and 46) of the first NFP collector 40 shown in FIGS. . In the NFP collector 40, the ceramic insulator 400 may cause an electrostatic barrier in the opening 404, and the performance of removing fine particles by the NFP collector 40 may deteriorate.
In order to eliminate the influence of such an electrostatic barrier, the conductor 402 of the first NFP collector 40 is replaced with a conductor 422 protruding from the insulator 400, and the second NFP shown in FIG. The collector 42 is assumed.
By replacing the first NFP collector 40 with the second NFP collector 42 in the plasma CVD apparatus 1, the fine particles in the lower electrode (inside) 32 can be more efficiently removed.
[0032]
Further, as shown in FIG. 11, an exhaust port 446 is provided at the end opposite to the opening 424 of the second NFP collector 42, and the fine particles sucked by the conductor 422 are exhausted from the plasma CVD apparatus 1. A third NFP collector 44 that discharges out of the vacuum vessel 100 can be obtained by using a system (not shown).
In the plasma CVD apparatus 1, the first and second NFP collectors 40 and 42 are replaced with the third NFP collector 44, so that the fine particles of the lower electrode (inside) 32 can be more efficiently removed. .
It should be noted that an exhaust port 446 can be added to the second NFP collector 42 to obtain the same effect.
[0033]
FIG. 13 is a cross-sectional view of the fourth NFP collector 46 shown in FIG.
The main body 466 of the fourth NFP collector 46 is disposed around the lower electrode 30 (lower electrode (inside) 32), as shown in FIG.
The main body 468 of the fourth NFP collector 46 has a configuration in which the 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 main body 468 is positioned at the opening 300-i of the lower electrode 30 (i = 1 to 8 in the example shown in FIG. 3 and the like). A combined opening 464-i is provided.
[0034]
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. 1 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 that of the second or third NFP collectors 42 and 44 can be obtained. Obtainable.
[0035]
[Others]
FIG. 14 is a diagram illustrating the lower electrode (inside) 32 in which four fine particle guiding grooves 320-1 to 320-4 are formed.
The number of fine particle guide grooves 320 may be one or more.
The number of the fine particle guiding grooves 320 may be four as shown in FIG. 14, for example, 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. .
[0036]
【The invention's effect】
As described above, the fine plasma processing apparatus according to the present invention can effectively remove charged fine particles generated during processing on a substrate.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a plasma CVD apparatus to which fine particle removal according to the present invention is applied.
FIG. 2 shows an electrostatic potential pattern between an upper electrode and a lower electrode in a plasma CVD apparatus (FIG. 1) to which fine particle removal 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 is opposed to a lower electrode (inside) used in a plasma CVD apparatus (FIG. 1) to which fine particle removal according to the present invention is applied, and one or more fine particle guiding grooves formed in the lower electrode (inside). FIG. 2 is a perspective view showing negatively charged fine particle (NFP) collectors arranged in the same manner.
4 is a diagram showing connections between the upper electrode, the lower electrode (inside) and the first NFP collector shown in FIGS. 1 to 3, and a high-frequency power source and a DC power source. FIG.
FIG. 5 is a perspective view illustrating the first NFP collector shown in FIG. 3;
6 is a diagram showing a configuration of a first NFP collector shown in FIG. 5; 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.
FIG. 8 is a view showing a second modification (third particle guide groove) of the first particle guide groove shown in FIGS. 2 to 4;
FIG. 9 is a view showing a first particle guide groove filled with an insulator.
10 is a view 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: Capacitor,
124 ... DC power supply,
20 ... Upper electrode,
22 ... electrostatic potential pattern,
30, 32 ... lower electrode,
300 ... opening,
320, 322, 326, 330 ... particulate guide groove,
324 ... Semiconductor wafer mounting part,
328 ... Filling insulating material,
40, 42, 44, 46 ... NFP collector,
400, 460 ... insulator,
402, 422, 462 ... conductors,
404, 424, 464 ... opening,
446 ... exhaust port,
412 ... Electric wire,
466 ... main body,
470 ... exhaust pipe,

Claims (2)

Plasma is generated between an upper electrode disposed substantially horizontally and a lower electrode disposed substantially parallel to face the upper electrode, and at least the lower electrode Plasma generating means for charging to a first polarity;
A guide groove that is radially formed on the lower electrode and guides particles charged to the first polarity on the lower electrode;
An opening on the outer periphery of the lower electrode is provided at the end of the guide groove at a position facing the guide groove, and attracts the particles charged in the first polarity and guided to the guide groove. Particle attracting means to
The particle attracting means includes
The third electrode was charged to a second polarity different from the first polarity, or, have a suction means for sucking said third electrode and said third attracted particles to the electrode,
The guide groove formed in the lower electrode is
Formed so as to become wider toward the near end of the particle attracting means,
Formed so that the depth increases toward the near end of the particle attracting means, or
A plasma processing apparatus formed so as to be wide toward the near end of the particle attracting means and deeper toward the near end of the particle attracting means . Plasma is generated between an upper electrode disposed substantially horizontally and a lower electrode disposed substantially parallel to face the upper electrode, and at least the lower electrode Plasma generating means for charging to a first polarity;
A guide groove that is radially formed on the lower electrode, is filled with an insulator, and induces particles charged to the first polarity on the lower electrode;
An opening on the outer periphery of the lower electrode is provided at the end of the guide groove at a position facing the guide groove, and attracts the particles charged in the first polarity and guided to the guide groove. Particle attracting means to
The particle attracting means includes
A plasma processing apparatus, comprising: a third electrode charged to a second polarity different from the first polarity, or suction means for sucking particles attracted to the third electrode and the third electrode.

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