JP2000091320A - Plasma treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve uniformity of the plasma treatment by means of a plasma treatment apparatus. SOLUTION: In a plasma treatment apparatus, in which plasma generating spaces 22, are scattered adjacent to a plasma treating space 13 in such a way that the spaces 22 are communicated with the space 13, a plasma generating gas A is introduced (50) into the plasma generating spaces 22, and a process gas B is introduced separately (70) into the plasma treating space 13 from the gas A. Then an additive gas C is introduced (60) into the plasma generating spaces 22 and mixed with the plasma-generating gas A, in such a way that the distribution of the mixing ratio is wade different locally (80). Only a nonreaction gas is used for the gas A, and a reaction gas is used for the gas B. In addition, a by-product gas corresponding to a by-product or a different nonreactive gas is used for the gas C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus suitable for appropriately performing a plasma processing in a high-precision manufacturing process for an IC, an LCD, or the like.

[0002]

2. Description of the Related Art Conventionally, as an example of a plasma processing apparatus used for plasma processing such as CVD, etching and ashing, a pair of parallel flat plates serving as opposed electrodes is provided, and a plasma processing space is formed between these parallel flat plates. A so-called parallel plate etcher (RIE) for performing an etching process on a substrate such as a silicon wafer and a parallel plate PCVD for performing a film forming process are known. In addition to generating and forming plasma required for plasma processing in a plasma processing space, ECR (Electron Cyclotron Resonance),
ICP (Inductive Coupled Plasma), TCP Plasma (Transformed Coupled Plasma), etc.
It is also known to perform the process in a plasma generation space formed separately from the plasma processing space.

In any case, a dense and uniform plasma processing is required regardless of the size or the size of the substrate or the like to be processed. Therefore, the distribution of the processing gas or the plasma state is uniform over the entire upper surface of the substrate or the like. It is necessary to ensure the nature. As a countermeasure, for example, as the size of the substrate increases, a number of processing gas inlets are provided and the distribution thereof is devised, or a plasma gas responsible for plasma generation and a processing gas responsible for plasma reaction are separated. Was introduced.

[0004]

In such a conventional plasma processing apparatus, uniform processing is performed based on uniform introduction of a processing gas or a plasma gas. However, in the plasma processing space, the processing gas reacts with the object to be processed to generate various by-products, and the density of the by-products may affect the reaction state. Further, in the plasma processing space, in addition to gas diffusion, there are various flows that disturb the uniformity. For this reason, even if the processing gas and the plasma gas are uniformly distributed and introduced, it is not always the case that a uniform processing is achieved over the entire surface.

However, it is conceivable to make the distribution of the introduced gas locally different from the uniform distribution so as to compensate for the non-uniformity of the plasma processing. However, even if a desired uniform processing is performed macroscopically and globally by such compensation, there may be a case where it is inhomogeneous when microscopically and locally viewed. For example,
In the etching of a silicon wafer, even when the etching rate is almost uniform over the entire surface of the wafer and the depth of the etching groove is uniform, comparing the cross-sectional shapes of the individual grooves, the degree of rounding of the corner and the opening Irregularities are seen in the change in diameter from the part to the bottom.

Therefore, in securing uniformity of the plasma processing, not only macroscopic / global uniformity but also microscopic / global uniformity is required.
The challenge is to devise so that local uniformity can be obtained. The present invention has been made to solve such a problem, and has as its object to realize a plasma processing apparatus having excellent plasma processing uniformity.

[0007]

Means for Solving the Problems First to fourth solving means invented to solve such problems are as follows.
The configuration and operation and effect will be described below.

[First Solution] A plasma processing apparatus according to a first solution (as described in claim 1 at the beginning of the application) is a plasma processing apparatus in which a plasma processing space is formed in a vacuum chamber. A first gas introduction passage for introducing a plasma gas into the plasma processing space;
A second gas introduction path provided separately from the gas introduction path for introducing a processing gas into the plasma processing space, a third gas introduction path for introducing an additional gas into the plasma processing space, and And a mixing means for mixing the plasma gas and the additive gas at the time of introducing the gas, and for locally varying or varying the distribution of the mixing ratio during the mixing.

[0009] In the plasma processing apparatus of the first solution, the object to be processed placed in the plasma processing space is subjected to the plasma processing. In addition to the plasma gas and the processing gas, an additional gas is also introduced into the plasma processing space through the gas introduction path. The plasma gas and the processing gas are separately introduced, while the additive gas is mixed with the plasma gas and introduced. Moreover, the distribution of the mixing ratio is locally changed by the mixing means.

In this case, since the plasma gas and the processing gas are separately introduced, by independently controlling the flow rate and distribution state of the processing gas, the processing gas distribution and the plasma distribution over almost the entire area of the object to be processed. The uniformity of the state is ensured, and the macroscopic / global uniformity in the plasma processing is achieved. In addition, the distribution of the mixing ratio of the added gas to the plasma gas is made to be locally different, but by making the distribution correspond to microscopic and local non-uniformity,
The microscopic / local uniformity is also improved without impairing the macroscopic / global uniformity. In addition, as the additive gas, a gas different from the processing gas is used, and its activity is likely to be insufficient.
By being mixed and introduced into the plasma gas, it is sufficiently excited and is useful without waste. Therefore,
According to the present invention, it is possible to realize a plasma processing apparatus having excellent plasma processing uniformity from a microscopic / local viewpoint in addition to a macroscopic / global viewpoint.

[Second Solution] A plasma processing apparatus according to a second solution (as described in claim 2 at the time of filing the application) comprises a first mechanism having a plasma processing space formed therein and the first mechanism. A second mechanism attached to or integrally provided with the plasma generation space and formed in a dispersed manner,
In the plasma processing apparatus, wherein the plasma generation space is adjacent to and communicates with the plasma processing space, a first gas introduction path for introducing a plasma gas into the plasma generation space, and a first gas introduction path separate from the first gas introduction path. A second gas introduction path for introducing a processing gas into the plasma processing space, a third gas introduction path for introducing an additional gas into the plasma generation space, and a gas supply path for introducing the plasma into the plasma generation space. And a mixing means for mixing the gas and the additive gas and for locally varying the distribution of the mixing ratio during the mixing.

Here, the above "dispersion etc." means not only literal dispersal of being scattered in a point-like manner, but also cases of being divided so as not to be close to each other,
When a plurality, or a mixture thereof, of a linear shape, a broken line shape, a straight shape, a curved shape, or the like is distributed in an adjacent portion or a communicating portion with the plasma processing space, further, a ring shape, a circular shape, a polygon shape, a spiral shape It is also applicable that many of them are concentrically or non-concentrically arranged in a row or formed independently and widely.

In the plasma processing apparatus according to the second solution, by maintaining the conditions of separation of the plasma space and adjacent communication, reduction in plasma damage and charge-up, and reduction of radical species components in the plasma And the ratio of the components of the ionic species are optimized.
In addition, since the plasma generation space is formed in a dispersed manner, not only uniformity of the plasma distribution is ensured, but also the adjacent surface communicating with the plasma processing space and the plasma generation space itself along the surface are cut off. Since the area is inevitably smaller than that of the plasma processing space and gas inflow from the plasma processing space to the plasma generation space is prevented,
It is possible to prevent the reactive processing gas from being exposed to the high-density plasma and being transformed into undesired contaminants.
Good plasma is supplied to the plasma processing.

When the object to be processed placed in the plasma processing space is subjected to the plasma processing, it is added through the first to third gas introduction paths in addition to the plasma gas and the processing gas. Gas is also introduced into the plasma processing space. In addition, at this time, the plasma gas and the processing gas are separately introduced, whereas the additive gas is mixed with the plasma gas and introduced. Further, the distribution of the mixing ratio of the additive gas is locally changed by the mixing means.

Since the plasma gas and the processing gas are separately introduced as described above, by independently controlling the flow rate and the distribution state of the processing gas, the processing gas distribution and the plasma distribution over almost the entire area of the object to be processed. The uniformity of the state is ensured, and the macroscopic / global uniformity in the plasma processing is achieved. In addition, the distribution of the mixing ratio of the added gas to the plasma gas is made to be locally different, but by making the distribution correspond to microscopic and local non-uniformity,
The microscopic / local uniformity is also improved without impairing the macroscopic / global uniformity.

The additive gas is a gas different from the processing gas, and its activity tends to be insufficient. However, the additional gas is introduced after being mixed with the plasma gas and introduced after passing through the plasma generation space. As a result, it is sufficiently excited to be useful without waste. Further, since it is not conceivable that the material is exposed to the high-density plasma like the processing gas and is transformed into undesired contaminants, the quality of the plasma is not deteriorated. Therefore, according to the present invention, it is possible to realize a plasma processing apparatus having excellent plasma processing uniformity from a microscopic / local viewpoint in addition to a macroscopic / global viewpoint.

[Third Solution] The plasma processing apparatus of the third solution (as described in claim 3 at the beginning of the application) is the plasma processing apparatus of the first and second solutions. Means for supplying only the non-reactive gas as the plasma gas to the first gas introduction path, and means for supplying a gas containing a reactive gas component as the processing gas to the second gas introduction path Means for supplying a gas containing a by-product gas corresponding to a by-product generated by the reaction gas reacting with the object to be processed in the plasma processing space as the additional gas to the third gas introduction path; It is provided with.

In the plasma processing apparatus according to the third solution, uneven distribution of by-products caused by the plasma processing is directly eliminated by the additional gas. As a result, the non-uniformity caused by the by-products is accurately improved, and the microscopic and local uniformity is maintained without deteriorating the macroscopic / global uniformity based on the plasma gas and the processing gas. Will be obtained.

[Fourth Solution] The plasma processing apparatus of the fourth solution (as described in claim 4 at the beginning of the application) is the plasma processing apparatus of the first and second solutions. Means for supplying only the non-reactive gas as the plasma gas to the first gas introduction path, and means for supplying a gas containing a reactive gas component as the processing gas to the second gas introduction path And means for supplying only the non-reactive gas having a different component or component ratio from the plasma gas as the additional gas to the third gas introduction path.

In the plasma processing apparatus according to the fourth solution, a non-reactive gas is mixed and introduced into the plasma generating space or the plasma processing space. Since the difference is observed and the mixing ratio is locally different, a local variation also occurs in the temperature distribution of the plasma supplied to the plasma processing space. Also, by associating such plasma temperature distribution with microscopic and local non-uniformity, microscopic and global uniformity based on the plasma gas and the processing gas is not impaired. Visual and local uniformity can be indirectly improved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the plasma processing apparatus of the present invention achieved by the above solution will be described with reference to the following first to seventh embodiments and modifications. The first embodiment shown in FIGS. 1 to 3 embodies the above-described second and third solutions, and the second embodiment shown in FIG. 4 implements the second and fourth solutions. The third embodiment shown in FIG. 5 and the fourth embodiment shown in FIG. 6 also embody the means described above. The fifth embodiment shown in FIG. 7 and the sixth embodiment shown in FIG. 8 are suitable for realizing any of the above-described second and third solving means or the above-described second and fourth solving means. ,
The seventh embodiment shown in FIG. 9 embodies the second, third, and fourth solving means described above. Further, a modified example, which is not shown, embodies the first solution means described above.

[0022]

First Embodiment A specific configuration of a plasma etching apparatus as a first embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic diagram showing a part in cross section, FIG. 2 is a vertical cross-sectional perspective view around a plasma generation space, and FIG. 3 is a vertical cross-sectional view in which a plasma processing space and the like are added thereto. is there.

This plasma etching apparatus comprises a vacuum chamber comprising a vacuum chamber main body 2 and a vacuum chamber lid 3, a parallel plate portion (first mechanism) for securing a plasma processing space therein, and a plasma generation space. An adjacent mechanism part (second mechanism) for securing the pressure and an additional part thereof, an application circuit part for applying an electric field or a magnetic field to each plasma, a pressure control part for keeping the inside of the vacuum chamber in a vacuum state, A gas supply unit for introducing an additional gas in addition to the plasma gas and the processing gas.

The parallel plate portion has a pair of parallel flat plates and an anode portion 11 and a cathode portion 12 both made of metal in a vacuum chamber. Lower support 1 at inner bottom
The cathode portion 12 supported by 2a is disposed below, and the low-temperature plasma 10
Plasma processing space 13 is formed. The upper surface of the cathode section 12 is insulated to mount the substrate 1 such as a wafer to be etched. In addition, the anode section 11 has a large number of communication ports 14 in advance.
Are pierced through the plasma processing space 13.
A processing gas supply port 15 is also formed as a second gas introduction path that opens to the side. This allows
The processing gas B is supplied to the plasma processing space 13 via the processing gas supply port 15. In this example, the ratio of the cross-sectional area of the communication port 14 to the effective cross-sectional area of the plasma processing space 13, that is, the first ratio is 0.05.

The adjacent mechanism, that is, the mechanism adjacent to one of the pair of parallel flat plates 11 is mainly composed of a plasma generation chamber 21 made of an insulating material. A plurality of (four in the figure) annular grooves 22 are concentrically engraved and formed. Thus, the plasma generation space 22 is dispersed. The plasma generation chamber 21 is fixedly mounted with the opening side (the lower surface in the figure) of the plasma generation space 22 in close contact with the upper surface of the anode unit 11. At this time, the positioning is performed so that the opening of the plasma generation space 22 overlaps the communication port 14 of the anode unit 11. Thereby, the plasma generation space 22 and the plasma processing space 13 are adjacent to each other and communicate with each other. In this example, the ratio of the cross-sectional area of the communication port 14 to the cross-sectional area of the plasma generation space 22 is 0.5. As a result, the plasma generation space 22 becomes the plasma processing space 13
Is smaller than the area of the plasma generation space 22 and slightly narrowed. The values of these ratios can be freely changed as long as the magnitude relation is not reversed.

In the plasma generation chamber 21, a first gas introduction path and a plasma gas supply path 23 as a third gas introduction path are formed in a ring further in the plasma generation space 22. The plasma generation space 22 receives the supply of the plasma gas A and the additional gas C from the bottom (the upper side in the figure) to generate the high-density plasma 20 and communicates with the plasma through the communication port 14. It is sent to the processing space 13. Further, the back surface (upper surface in the figure) of the plasma generation chamber 21 on the opening side of the plasma generation space 22 is cut away so as to leave the side wall and the bottom surrounding the plasma generation space 22. Then, the coil 24 and the permanent magnet piece 25 are annularly added so as to sandwich both side walls of the plasma generation space 22.

The permanent magnet piece 25 has a vertical length substantially equal to that of the plasma generation space 22 and the magnetic poles are oriented in the direction of the horizontal plasma generation space 22, and further cuts off an undesired annular induced current. Therefore, it is formed into small pieces. A large number of permanent magnet pieces 25 are arranged along the side wall of the plasma generation space 22 to form an annular magnetic circuit corresponding to the plasma generation space 22. As a result, the magnetic member 25 for the magnetic circuit is arranged at a position other than the outermost periphery sandwiched between the plasma generation spaces 22. The magnetic force of this magnetic circuit needs only to be strong enough to capture electrons having a small mass, and does not need to be strong enough to capture ions having a large mass.

The application circuit section is divided into a first application circuit centered on the RF power supply 31 and a second application circuit centered on the RF power supply 32. The output power of the RF power supply 31 is variable. The output of the RF power supply 31 is supplied to the cathode section 12 via a blocking capacitor in order to apply an alternating electric field to the grounded anode section and generate a bias voltage. Will be sent. This also includes a frequency of 500
A frequency of KHz to 2 MHz is often used. Thus, the first application circuit applies an electric field that contributes to the strengthening of the low-temperature plasma 10 to a certain extent to the plasma processing space 13.

The RF power source 32 also has a variable output power, and has two coils 2 sandwiching the plasma generation space 22.
4 is applied to apply an alternating magnetic field to the plasma generation space 22. Its maximum output power is large, and its frequency is often 13 MHz to 100 MHz. Thereby, the second application circuit is provided with the high-density plasma 20.
The magnetic field contributing to generation and enhancement of the plasma is generated in the plasma generation space 2
2 is applied.

The pressure controller comprises a vacuum pump 5, a movable wall 40, and wall driving mechanisms 41 to 44 for moving the movable wall 40 up and down. As the vacuum pump 5, a rotary pump, a mechanical booster, or the like is used. The vacuum pump 5 is connected to a suction port 2a formed through the vacuum chamber main body 2 via a gate valve 4, and sucks and exhausts gas in the vacuum chamber. It is supposed to.

The movable wall 40 is formed of a metal cylindrical body, and has an inner diameter slightly larger than the outer diameter of the cathode portion 12, so that the cathode portion 12 is loosely fitted in the inner cavity so as to be vertically movable. ing. At the upper end, when approaching the anode portion 11, a substantially identical gap 45 is formed at the entire periphery. At this time, the movable wall 40 is formed to have a length such that the upper part closes the periphery of the side surface of the plasma processing space 13 and the lower part reaches a position where the fitting with the cathode part 12 does not come off. Thereby, the movable wall 4
Reference numeral 0 denotes a shape provided in the vacuum chambers 2 and 3 and surrounding the opening of the plasma processing space 13 with reference to the pair of parallel flat plates 11 and 12. And the gap 4
5 is a variable throttle for the flow of exhaust gas from the vacuum pump 5, and the pressure in the plasma processing space 13 is determined according to the flow rates of the gases A, B, and C and the vertical position of the movable wall 40. The movable wall 40 is grounded or the like so as not to be undesirably charged up.

The wall driving mechanisms 41 to 44 connect the bottom surface of the vacuum chamber main body 2 and the movable wall 40 at a position where the airtight and elastic bellows 41 do not overlap the suction port 2a. A ball screw 42 is vertically inserted into 41, and the upper end thereof is connected to the movable wall 40, and supports the movable wall 40 so as to be able to move up and down. further,
The lower end of the ball screw 42 is connected to a rotation shaft of a motor 44 fixed to the vacuum chamber main body 2 by a support 43. Then, when the motor 44 rotates, the ball screw 42 is driven forward and backward in response to this, and the movable wall 40 is driven up and down accordingly, and the upper part is almost in contact with the anode part 11 and the lower part is the upper surface of the cathode part 12. The movable wall 40 moves to a lower position. As a result, the wall driving mechanisms 41 to 44 move both the upper position where the movable wall 40 surrounds the opening of the plasma processing space 13 and the lower position where the movable wall 40 releases the opening of the plasma processing space 13. The movable wall 40 moves up and down in the vertical direction over the position.

The gas supply unit includes a processing gas supply unit 70 for supplying a processing gas B, a plasma gas supply unit 50 for supplying a plasma gas A, and an additional gas supply unit 60 for supplying an additional gas C. A pipe or the like that guides the gases A, B, and C to the plasma processing space 13 and the plasma generation space 22, and a part of the pipe and the like is a pipe unit 8.
It is 0.

The plasma gas supply unit 50 includes a gas cylinder 51 for storing the plasma gas A and a mass flow controller 52 for adjusting the amount of gas flowing out of the gas cylinder 51 under the control of a main controller (not shown).
An on-off valve 53 which is connected to the mass flow controller 52 in consideration of safety and maintenance work, and is opened only when gas is supplied, and pipes 81, 82, etc., which extend toward the vacuum chamber cover 3 and extend therefrom. And a pipe 54 that finally communicates with the gas supply path 23 for plasma. The gas cylinder 51 is filled with a non-reactive gas such as argon, and a plasma gas A composed of the non-reactive gas is used.
When the on-off valve 53 is open, the mass flow controller 5
The flow rate corresponding to the setting of 2 is sent to the plasma gas supply path 23 via the pipes 54, 81, 82. As a result, the pipes 54, 81, and 82 are connected to the plasma generation space 2
2 is a first gas introduction passage for introducing a plasma gas A, and the gas cylinder 51 supplies only the non-reactive gas as the plasma gas A to the first gas introduction passage. ing.

The processing gas supply unit 70 includes a processing gas B
Gas tank 71 for storing gas, a mass flow controller 72 for adjusting the amount of gas flowing out of the gas cylinder 71 according to control of a main controller (not shown), and a mass flow controller 72 connected in consideration of safety, maintenance work, etc., only when supplying gas. An on-off valve 73 that is opened,
There is provided a pipe 74 extending toward the vacuum chamber lid 3, branching appropriately, further reaching the anode section 11, being distributed therein, and finally communicating with the processing gas supply port 15. The gas cylinder 71 is filled with a reaction gas such as a Freon gas or a silane gas mixed with an appropriate amount of a diluting gas. The processing gas B containing the reaction gas is supplied to the mass flow controller 72 when the on-off valve 73 is opened. Is supplied to the processing gas supply port 15 via the pipe 74 at a flow rate corresponding to the setting of (1). As a result, the pipe 74 is provided separately from the first gas introduction path and serves as a second gas introduction path for introducing the processing gas B into the plasma processing space 13. The contained gas is supplied to the second gas introduction path as the processing gas B.

The additive gas supply unit 60 includes an additive gas C
61, a mass flow controller 62 for adjusting the amount of gas flowing out of the gas cylinder 61 according to control of a main controller (not shown), and a mass flow controller 62 connected in consideration of safety, maintenance work, and the like, only when supplying gas. An on-off valve 63 that is opened,
From there, it extends toward the vacuum chamber cover 3, branches off as appropriate, reaches the pipe 82, and joins there, and finally has a pipe 64 communicating with the plasma gas supply path 23. Then, when the on-off valve 63 is open, the additive gas C is sent into the plasma gas supply path 23 via the pipes 64 and 82 by a flow rate corresponding to the setting of the mass flow controller 62. As a result, the pipes 64 and 82
This is a third gas introduction path for introducing the additional gas C into the plasma generation space 22.

The gas cylinder 61 is filled with oxygen gas, so that the gas cylinder 61 supplies oxygen gas as an additional gas C to the third gas introduction path. Then, the oxygen gas is supplied to the plasma processing space 13.
It is a by-product gas corresponding to a by-product generated from the article 1 to be processed. That is, when etching a silicon wafer or the like, by-products containing carbon, oxygen, and the like are generated from the organic resist on the surface of the silicon wafer, and the by-products are converted into a gas or ions and mixed into the low-temperature plasma 10 in the plasma processing space 13. In this case, oxygen and oxide contribute to the improvement of etching removability and etching shape if the concentration is appropriate. Therefore, oxygen gas is used as the additive gas C.

In the piping unit 80, the piping 54
From the branch to the gas supply path 23 for plasma, that is, the pipe 81 and the pipe 82.
The pipe 81 branches off from the pipe 54 and directly communicates with one of the plasma gas supply paths 23, and the plasma gas supply path 23 is the second from the inside. Although the reference numerals and detailed illustrations are omitted, the pipe branched from the pipe 54 is directly connected to the third and subsequent outer plasma gas supply paths 23 counted from the inner side. On the other hand, piping 8
Numeral 2 communicates with the innermost plasma gas supply passage 23. In addition, a pipe 64 from the additive gas supply unit 60 is connected on the way from the pipe 54 to the plasma gas supply path 23. And plasma gas A
Is distributed to all the plasma gas supply paths 23,
The additive gas C joins the plasma gas A at the pipe 82 and is sent only to the innermost plasma gas supply passage 23, so that the additive gas C is mixed with the plasma gas A at the center. On the other hand, it is not mixed in the peripheral portion. Thus, the piping etc. unit 80 is a mixing means for mixing the plasma gas A and the additive gas C when introducing them into the plasma generation space 22 and for locally varying the mixing ratio distribution during the mixing.

The usage and operation of the plasma processing apparatus of the first embodiment will be described.

In use, the vacuum chamber lid 3 is closed, and the inside of the vacuum chamber main body 2 and the plasma processing space 13 and the plasma generation space 22 are also sealed. Then, the movable wall body 40 is lowered below the cathode section 12, and in this state, the horizontal substrate 1 is carried into the vacuum chambers 2 and 3 from the side via a substrate carrying port (not shown) or the like. Is placed on the upper surface of the cathode section 12.
Then, at the same time as closing the substrate carrying-in port and the like, the evacuation by the vacuum pump 5 is performed. At this time, the gate valve 4 remains open, and the inside of the vacuum chambers 2 and 3 quickly becomes a vacuum state.

Then, the motor 44 is rotated to raise the movable wall 40 so that it does not come into contact with the anode portion 11.
The supply of the plasma gas A by the plasma gas supply unit 50, the supply of the additional gas C by the additional gas supply unit 60, and the processing gas B by the processing gas supply unit 70
When the supply and the like are appropriately started, the pressure in the plasma processing space 13 is appropriately maintained by using the gap 45 formed between the upper end of the movable wall body 40 and the lower surface of the anode unit 11 as a throttle. At this time, the plasma gas A flows into the plasma processing space 13 through the distributed plasma generation space 22 and the communication port 14 in a distribution state close to a uniform distribution. Further, the processing gas B also flows into the plasma processing space 13 via the multiple processing gas supply ports 15 in a distribution state which is also close to a uniform distribution. However, since the additive gas C is mixed only with the plasma gas A in the central portion, it becomes dense in the central portion into which it flows, but spreads while flowing toward the gap 45, and becomes thinner in the peripheral portion toward the outside.

The narrowed portion formed by the gap 45 is formed almost uniformly around the upper part of the plasma processing space 13.
According to the difference between the pressure inside the plasma processing space 13 and the pressure inside the vacuum chamber outside the same, the flow of the passing fluid such as gas is almost the same anywhere in the throttle section. Is almost symmetrical and highly uniform. Further, such a pressure state is maintained even when plasma is formed in the plasma processing space 13, so that
Low-temperature plasma 10 in the etching process described below
Is also substantially symmetric and highly uniform. Thus, the preparation for the plasma etching process on the substrate 1 mounted on the cathode unit 12 is completed.

Next, when the RF power source 32 is operated, an RF electromagnetic field is applied to the plasma generating space 22 through the coil 24, and the electrons of the plasma gas A are violently moved. At this time, the electrons stay in the plasma generation space 22 for a long time due to the action of the magnetic circuit by the permanent magnet pieces 25,
The gas A for plasma and the additional gas C are excited while helically moving in the annular space. Thus, the high-density plasma 20 is generated, but the electrons sealed in the plasma generation space 22 greatly contribute to the generation of ion species.
The high-density plasma 20 has a high ratio of ionic species components because many of them have high energy of 5 eV or more.
Then, the high-density plasma 20 expanded in the plasma generation space 22, especially its radical species and ionic species components,
Due to the expansion pressure, the liquid is quickly transferred to the plasma processing space 13.

When the RF power supply 31 is operated, the anode section 11 and the cathode section 1 are also placed in the plasma processing space 13.
2, an RF electric field is applied. Since there is no magnetic circuit or the like that can confine electrons, even if the processing gas B or the like is excited, high-density plasma cannot be generated.
Becomes When only the power from the RF power source 31 is used, the low-temperature plasma 10 has a small amount of electrons having energy of 10 to 15 eV or more, so that the ratio of radical species components increases. However, in the case of the low-temperature plasma 10 in this apparatus, since the high-density plasma 20 is mixed, the actual ratio between the radical species component and the ionic species component is any ratio between the two.

When the outputs of the RF power supplies 31 and 32 are appropriately increased and decreased, the low-temperature plasma 1 is correspondingly increased.
At 0, the ratio of the radical species component to the ionic species component changes. The variable range is wide enough to cover almost all conventional models. Thus, the substrate 1
The etching process proceeds efficiently under the optimum conditions for the etching at that time based on the material of the material and the characteristics of the processing gas B.

Moreover, since the cross-sectional area of the plasma generation space 22 is much smaller than the cross-sectional area of the plasma processing space 13, the high-density plasma 20
2 is quickly sent out from the plasma processing space 13 to the plasma processing space 13 and the amount of gas flowing backward from the plasma processing space 13 to the plasma generation space 22 is small. There is almost no decomposition and ionization to a desired level, and the etching process using high-quality plasma proceeds efficiently. At this time, the processing gas B or the like is
And the low-temperature plasma 10 makes the etching rate and the like uniform over substantially the entire area of the main surface of the substrate 1, thereby performing a uniform etching process.

As described above, oxygen-containing by-products are generated from the organic resist applied on the main surface of the substrate 1 as described above, and the concentration distribution is changed from the center to the periphery. Since the superposed portion is superposed on the flow of the low-temperature plasma 10 toward the center portion, the portion is thin in the central portion, but becomes thicker in the outer portion in the peripheral portion. This distribution is opposite to the above-described concentration distribution of the additive gas C. And when you combine both,
The oxygen gas component is also distributed almost uniformly in the plasma processing space 13, and the low temperature plasma 10 makes the etching removal property and shape uniform over substantially the entire area of the main surface of the substrate 1, so that a uniform etching process is performed. . In this way, the concentration distribution of by-products is also improved, and not only macroscopic / global uniformity but also microscopic / local uniformity can be obtained.

[0048]

Second Embodiment A specific configuration of a second embodiment of the plasma processing apparatus according to the present invention will be described with reference to the drawings. FIG. 4 is an overall schematic diagram partially showing a cross section, and corresponds to FIG. 1 described above. This plasma processing apparatus (see FIG. 4) is different from the first embodiment (see FIG. 1) in that
The point is that the gas cylinder 61 is filled with, for example, xenon gas instead of the oxygen gas, and that the pipe connection state of the pipe and other units 80 is changed.

Xenon, helium, etc. are common to argon in the gas cylinder 51 in that they are non-reactive gases, but their temperatures are different even when they are similarly excited and turned into plasma in the same plasma generation space 22. As a result, the gas cylinder 61 uses the non-reactive gas having a component different from that of the plasma gas A as the additive gas C as the third gas introduction path 64.
It is the means to send to. In addition, a piping unit 8
In the case of 0, the junction of the pipe 64 is not the pipe 82 leading to the inner plasma gas supply path 23 of the branch pipe of the pipe 54 but the pipe leading to the outermost plasma gas supply path 23. .

In this case, when the flow rate of the additive gas C is changed by the flow control valve 62, the mixing ratio of xenon to argon changes in the peripheral portion of the plasma processing space 13, and the low-temperature plasma 10 thereupon is changed accordingly. Temperature fluctuates. Since the flow rate of the additive gas C is smaller than that of the plasma gas A or the processing gas B, the concentration distribution of the processing gas B or the like hardly changes. In this way, it is possible to compensate for heterogeneous local non-uniformity caused by, for example, a decrease in plasma temperature in the peripheral portion, without impairing uniform processing based on the concentration distribution of the processing gas B.

[0051]

Third Embodiment A specific configuration of a third embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 5 is an overall schematic diagram showing a part in cross section, and corresponds to FIGS. 1 and 4 described above. This plasma processing apparatus (see FIG. 4) is different from that of the first embodiment (see FIG. 1) in that the pipe connection state of the pipe etc. unit 80 is changed.

That is, in the above-described example, the junction of the pipes 64 is directed only to the innermost plasma gas supply passage 23. In this example, the pipes 64 are branched first, Is joined to the branch pipe of the pipe 54 so as to be directed to a plurality of plasma gas supply paths 23 on the inside except the outermost side, and the additive gas C is distributed. Each time the pipe 64 branches, the orifice 8
3 is inserted, and the more the outer branch pipe, the more the throttle works so that the flow rate is reduced. However, by adjusting the hole diameter of the orifice 83 or removing the orifice 83, the additional gas C is removed.
Can be adjusted or changed. As a result, the unit 80 such as the piping is separated from the plasma generation space 2.
The mixing means mixes the plasma gas A and the additive gas C at the time of introduction into the nozzle 2 and simultaneously locally varies the distribution of the mixing ratio during the mixing.

In this case, the additive gas C is also dense in the central portion and thin in the peripheral portion, but is slightly added in the middle, so that the concentration change becomes gentle. In this way, the concentration distribution of the by-products can be improved more finely and appropriately than in the above-described example.

[0054]

Fourth Embodiment A specific configuration of a fourth embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 6 is an overall schematic diagram showing a part in cross section, and corresponds to FIG. 5 described above.

This plasma processing apparatus (see FIG. 6) is different from that of the third embodiment (see FIG. 5) in that the processing gas supply port 15 is divided into four parts from the inner peripheral part to the outer peripheral part. The pipe 74 is also branched first, and each branch pipe communicates with the processing gas supply port 15 of each section.
Is an interposed point. In this case, the distribution state of the processing gas B can be changed near the center. Moreover, by manually operating the choke 84, the distribution state can be finely adjusted even when the device is in operation.

[0056]

Fifth Embodiment A specific configuration of a fifth embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 7 is an overall schematic diagram showing a part in cross section, and corresponds to FIG. 6 described above.

This plasma processing apparatus (see FIG. 7) is different from that of the fourth embodiment (see FIG. 6) in that the pipes 64 also have the same number of branches as the pipes 54 and join each other. Reference numeral 84 denotes a point inserted into each of the branch pipes of the pipes 54, 64, and 74. In this case, the distribution of the mixing ratio of the plasma gas A and the additive gas C can be made different for each region corresponding to each section. In addition, each gas A,
Both B and C can be adjusted bi-directionally.

[0058]

Sixth Embodiment A specific configuration of a sixth embodiment of the plasma processing apparatus of the present invention will be described with reference to the drawings. FIG. 8 is an overall schematic diagram showing a part of the cross section, and corresponds to FIG. 7 described above.

The difference between this plasma processing apparatus (see FIG. 8) and the fifth embodiment (see FIG. 7) is that the choke 84 is used.
Are replaced by the mass flow controller 85. Accordingly, the mass flow controllers 52, 62, and 72 are omitted. In this case, the flow rate of each mass flow controller 85 is preset as a so-called recipe in a main controller (not shown) or the like, so that the concentration distribution of the plasma gas A, the distribution of the mixing ratio of the additive gas C thereto, and the processing gas B Can be automatically adjusted.

[0060]

Seventh Embodiment A specific configuration of a seventh embodiment of the plasma processing apparatus according to the present invention will be described with reference to the drawings. FIG. 9 is an overall schematic diagram showing a part in cross section, and corresponds to FIG. 8 described above.

This plasma processing apparatus (see FIG. 9) differs from that of the sixth embodiment (see FIG. 8) in that an additional gas supply unit 90 is added. Like the additive gas supply unit 60, the additive gas supply unit 90 includes a gas cylinder 91, an on-off valve 93, and a pipe 94, and supplies the additive gas D. Then, the pipe 94 also branches in the same manner as the pipe 64, and is individually inserted through the mass flow controller 85 to join the branch pipe of the pipe 64 for each branch pipe. In this case, the gas cylinder 61 is filled with oxygen gas, the gas cylinder 91 is filled with helium gas,
Each of them is introduced into the plasma generation space 22 and the plasma processing space 13 with an appropriate distribution according to the recipe.

[0062]

[Modification] In the above embodiment, the mixing of the plasma gas A and the additional gases C and D is performed by the piping unit 80, but the mixing location is not limited to the piping portion. The plasma gas supply path 23 and the plasma generation space 2
It may be 2. In addition, the gas cylinders 61 and 9 serve as a part of the additive gases C and D that have a constant mixing ratio.
The number is not limited to 1, and may be mixed in the gas cylinder 51 or the gas cylinder 71 in advance. As the additive gases C and D, nitrogen as well as oxygen is used, which is useful for both etching and CVD. Nitrogen oxides (N ₂ O, NO ₂₎ and carbon (CO _2, CO) is also good.

Furthermore, in the above-described embodiment, a specific example in which the plasma space is separated into a plasma generation space and a plasma processing space has been described. However, the application of the present invention is limited to such a case. Even when the plasma generation space is not separated from the plasma processing space, the plasma gas A is introduced into the plasma processing space separately from the processing gas B, and the plasma gas A By adding the additive gas C to the mixture, it becomes possible and an appropriate effect can be obtained.

[0064]

As is apparent from the above description, in the plasma processing apparatus according to the first solution of the present invention, a plasma gas and a processing gas are separately introduced to provide a macroscopic / global system. While ensuring uniformity, the microscopic
Improves microscopic and local uniformity without impairing macroscopic and global uniformity by allowing additional gas to be introduced by matching the distribution of the mixing ratio to local nonuniformity As a result, there is an advantageous effect that a plasma processing apparatus having excellent plasma processing uniformity can be realized.

Further, in the plasma processing apparatus according to the second solution of the present invention, the plasma gas and the processing gas are separately introduced into the plasma generation space and the plasma processing space, respectively, to obtain good quality and macroscopic performance. As well as ensuring global uniformity, it is possible to introduce additional gas by adjusting the distribution of the mixing ratio to the remaining microscopic and local nonuniformity, so that macroscopic and global uniformity can be achieved. The microscopic and local uniformity is also improved without impairing the properties, etc.,
There is an advantageous effect that a plasma processing apparatus having excellent plasma processing uniformity can be realized.

Further, in the plasma processing apparatus according to the third solution of the present invention, the uneven distribution of by-products caused by the plasma processing is directly eliminated by the additional gas, so that There is an advantageous effect that the microscopic and local non-uniformity caused by the product can be accurately improved.

Further, in the plasma processing apparatus according to the fourth solution of the present invention, microscopic and local indirectly occur through local fluctuation of the plasma temperature distribution based on the mixing ratio of the non-reactive gas. By improving the non-uniformity, it is possible to realize a plasma processing apparatus having excellent plasma processing uniformity not only from a macroscopic / global perspective but also from a microscopic / local perspective. It has the advantageous effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram partially showing a cross section of a first embodiment of a plasma processing apparatus of the present invention.

FIG. 2 is a perspective view of a longitudinal section around a plasma generation space.

FIG. 3 is a longitudinal sectional view in which a plasma processing space and the like are added thereto.

FIG. 4 is an overall schematic diagram of a second embodiment of the present invention.

FIG. 5 is an overall schematic diagram of a third embodiment of the present invention.

FIG. 6 is an overall schematic diagram of a fourth embodiment of the present invention.

FIG. 7 is an overall schematic diagram of a fifth embodiment of the present invention.

FIG. 8 is an overall schematic diagram of a sixth embodiment of the present invention.

FIG. 9 is an overall schematic diagram of a seventh embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Substrate (wafer, processing object, to-be-processed object) 2 Vacuum chamber main body part (vacuum chamber) 2a Suction port 3 Vacuum chamber lid part (vacuum chamber) 4 Gate valve (gate valve) 5 Vacuum pump 10 Low temperature plasma 11 Anode part (One of parallel plates, first application circuit, first mechanism) 11a Upper support 12 Cathode (the other of parallel plates, first application circuit, first mechanism, substrate support) 12a Lower support 13 Plasma processing space 14 Communication port 15 Process gas supply port (second gas introduction path) 20 High density plasma 21 Plasma generation chamber (adjacent mechanism section, second mechanism) 22 Plasma generation space 23 Plasma gas supply path (first gas introduction path and second gas introduction path) 3
24 Coil (second application circuit) 25 Permanent magnet piece (magnetic member for magnetic circuit) 31 RF power supply (first application circuit) 32 RF power supply (second application circuit) 40 Movable wall (variable aperture) 41) Bellows (bellows, wall drive mechanism) 42 Ball screw (advance / retreat drive shaft, wall drive mechanism) 43 Support (post, wall drive mechanism) 44 Motor (motor, wall drive mechanism) 45 Restrictor 50 Plasma gas Supply unit (non-reactive gas supply device, first gas supply source) 51 Gas cylinder (gas storage unit) 52 Mass flow controller (flow rate control valve, variable flow rate unit) 53 Open / close valve 54 Pipe (first gas introduction path) 60 Addition Gas supply unit (secondary gas supply device, 3rd
Gas supply source) 61 Gas cylinder (gas storage section) 62 Flow control valve (flow rate variable section) 63 Open / close valve 64 Piping (third gas introduction path) 70 Processing gas supply unit (reactive gas supply device, second
Gas supply source) 71 Gas cylinder (gas storage section) 72 Flow control valve (flow rate variable section) 73 Open / close valve 74 Piping (second gas introduction path) 80 Piping unit (mixing means of first gas and third gas) 81 Piping (branch pipe, first gas introduction path) 82 Piping (branch pipe, first gas introduction path and third gas introduction path) 83 Orifice (mixing ratio distribution adjusting means) 84 Choke (variable throttle, mixing) Rate distribution adjusting means) 85 mass flow controller (flow rate control valve, mixing rate distribution adjusting means) 90 additive gas supply unit (supplying device for non-reactive gas, etc., third gas supply source) 91 gas cylinder (gas storage section) 93 opening and closing Valve 94 piping (third gas introduction path)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takayuki Hirano 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Inside Kobe Research Institute, Kobe Steel Ltd. (72) Inventor Toshihiro Kugimiya Takatsuka, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel, Ltd.Kobe Steel Research Institute Co., Ltd. (72) Inventor Toshihisa Nozawa 1-5-5, Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Kobe Steel Co., Ltd.Kobe Research Institute (72) Inventor Tetsuo Tokumura 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Inside the Kobe Research Institute, Kobe Steel (72) Inventor Jun Junsei 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture Co., Ltd. Kobe Steel, Ltd.Kobe Research Institute (72) Inventor Kiyotaka Ishibashi 1-5-5 Takatsukadai, Nishi-ku, Kobe City, Hyogo Prefecture F term in the joint research institute (reference) 4K030 AA14 AA18 CA04 DA04 EA01 EA05 FA01 JA06 LA15 4K057 DA16 DA20 DB20 DD01 DD03 DE14 DE20 DG06 DG07 DG08 DG12 DG13 DG20 DM02 DM03 DM06 DM14 DM22 DM23 DM37 DN01 5F004 AA01 BA04 BA04 BB18 BB28 BB29 BC03 BC08 BD07 CA02 CA09 DA00 DA22 DA23 DA25 DA26 DA28 DB00 5F045 AA08 AA10 AC11 AC15 AC16 AC17 BB02 DP02 DP03 EE12 EE20 EF05 EH04 EH05 EH11 EH12 EH13 EH16 EH17 EH19 EM09

Claims (4)

[Claims] In a plasma processing apparatus in which a plasma processing space is formed in a vacuum chamber, a first gas introduction path for introducing a plasma gas into the plasma processing space, and a first gas introduction path separately from the first gas introduction path. A second gas introduction path for introducing a processing gas into the plasma processing space, a third gas introduction path for introducing an additional gas into the plasma processing space, and the plasma gas when introducing the plasma gas into the plasma processing space. And a mixing means for mixing the additive gas and the distribution of the mixing ratio at the time of mixing, or a mixing means capable of changing the distribution. 2. A first mechanism having a plasma processing space formed therein, and a second mechanism attached to or integrated with the first mechanism and having a plasma generating space formed in a dispersed manner or the like. A plasma processing apparatus in which the plasma generation space is adjacent to and communicates with the plasma processing space;
A first step of introducing a plasma gas into the plasma generation space;
A gas introduction path, a second gas introduction path provided separately from the first gas introduction path for introducing a processing gas into the plasma processing space, and a third gas introducing an additional gas into the plasma generation space An introduction path, and mixing means for mixing the plasma gas and the additive gas upon introduction into the plasma generation space and distributing or locally varying the distribution of the mixing ratio upon mixing. Characteristic plasma processing apparatus. 3. A means for supplying only a non-reactive gas as the plasma gas to the first gas introduction path, and a means for supplying a gas containing a reactive gas component as the processing gas to the second gas introduction path. Means for supplying a gas containing a by-product gas corresponding to a by-product generated from an object to be processed in the plasma processing space to the third gas introduction path as the additional gas. The method according to claim 1 or 2, wherein
The plasma processing apparatus described in the above. 4. A means for supplying only a non-reactive gas as the plasma gas to the first gas introduction path, and a means for supplying a gas containing a reactive gas component as the processing gas to the second gas introduction path. And a means for supplying only the non-reactive gas having a component or a component ratio different from that of the plasma gas to the third gas introduction path as the additional gas. The plasma processing apparatus according to claim 1 or 2.