JPH05102085A - Plasma apparatus - Google Patents

Abstract

PURPOSE:To prevent a plasma production chamber from being contaminated by connecting a high-frequency power supply with an impurity adherence preventive member too by means of a changeover switch provided between a sample holding device and the high-frequency power supply. CONSTITUTION:When film is formed on a sample 24 by using a plasma apparatus 10, an adherence preventive member 16a is grounded via a changeover switch 30a, and an electrode 28 buried in a sample holding device 23 is connected to a high-frequency power supply 29 via switches 30b and 30c so as to form films on the sample. In order to remove deposits on the member 26a that is prepared on the side faces of a reaction chamber wall 12a and the device 23, the member 26a is connected to the power supply 29 via the switches 30a and 30c and then the electrode 28 buried in the device 23 is grounded via the switch 30b. thus, the deposits such as decomposition product or reactive product of process gas attached on the surface of the impurity adherence preventive member can be removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma device, and more particularly to a plasma device which utilizes electron cyclotron resonance (ECR) and is used for manufacturing highly integrated semiconductor devices.

[0002]

2. Description of the Related Art A method of generating plasma by electron cyclotron resonance excitation can generate highly active plasma in a low gas pressure region, a wide range of ion energy can be selected, and a large ion current can be generated. However, the research and development are being carried out as an essential factor for the production of highly integrated semiconductor devices and the like, because they have advantages such as excellent directivity and uniformity of ion flow.

FIG. 5 is a sectional view schematically showing a conventional electron cyclotron resonance plasma apparatus using microwaves. In the figure, reference numeral 80 denotes a plasma device. The plasma device 80 includes a plasma generation chamber 11 formed in a substantially columnar shape, and a reaction chamber 12 connected in a substantially columnar shape to the right side of the plasma generation chamber 11 in the figure. A microwave waveguide 13 for introducing microwaves into the plasma generation chamber 11 is provided on the left side of the plasma generation chamber 11, and is arranged concentrically with the plasma generation chamber 11 around the plasma generation chamber 11. It is composed of an exciting coil 14 and a sample holding device 23 and the like installed in the reaction chamber 12.

A microwave introduction port 16 for introducing microwaves is formed in the left side wall of the plasma generation chamber 11, and the microwave waveguide 13 is formed in a rectangular cross section and made of quartz. It is connected to the plasma generation chamber 11 via. Further, a gas introduction pipe 15 is connected to the left side wall of the plasma generation chamber 11 side by side with the microwave waveguide 13, and a cooling pipe 21 for cooling the plasma generation chamber 11 and the exciting coil 14 is further connected. ing.

The reaction chamber 12 has a larger diameter than the plasma generation chamber 11, and a second gas introduction pipe 17 is connected to the chamber wall 12a. Further, it is partitioned from the plasma generation chamber 11 by a partition plate 19, and a plasma drawing window 18 is formed in this partition plate 19. Furthermore, reaction chamber 1
An exhaust port 22 is formed in the second chamber wall 12a on the side opposite to the side to which the second gas introduction pipe 17 is connected, and is connected to an exhaust system (not shown). In addition, a sample holding device 23 is arranged in the right center portion of the reaction chamber 12, and the sample holding device 2
An electrode 28 is embedded in the electrode 3, and the electrode 28 is connected to a high frequency power source (not shown) so as to apply a high frequency to the sample 24 placed on the sample holding device 23.

[0006]

The plasma device 80 described above is used.
In addition, in addition to around the sample 24 by plasma irradiation,
Decomposition products and reaction products of the process gas adhere to the inner wall surface of the reaction chamber 12 and the side surface of the sample holding device 23 which are not directly exposed to plasma, and cause contamination of the sample 24. Therefore, a fluorine-based etching gas such as NF ₃ , SF ₆ , CF ₄ or a chlorine-based etching gas such as Cl ₂ is introduced into the reaction chamber 12, and plasma is generated to remove the deposits that cause contamination of the sample 24. Was going on. But,
Even if an attempt is made to etch contaminants adhering to the inner wall surface of the reaction chamber 12 or the side surface of the sample holding device 23 by introducing a fluorine-based or chlorine-based etching gas to generate plasma, the inner wall surface of the reaction chamber 12 or Since the side surface of the sample holding device 23 is originally a portion that is not directly exposed to plasma, there is a problem that the adhered matter cannot be completely removed.

Further, in order to prevent the decomposition products and reaction products of the process gas, which cause contamination, from adhering to the inner wall surface of the reaction chamber 12, the inner wall surface of the reaction chamber 12 and the sample holding device 2
Although it is also possible to prevent contamination of the sample 24 by covering the three side surfaces with a replaceable deposition-preventing member (not shown) and periodically replacing the deposition-preventing member, the reaction chamber 12 is regularly It takes a lot of time and money to replace the anti-adhesion member by itself, such as manually opening the anti-adhesion member and releasing the reaction chamber 12 into the atmosphere, so that moisture in the atmosphere in the reaction chamber 12 is removed. There is a problem that the gas flows in and causes corrosion of the inner wall surface of the reaction chamber 12 and increase of foreign matter.

Further, there is a problem in that the evacuation time is extended by releasing the reaction chamber 12 to the atmosphere, which causes inconvenience for stable operation of the plasma device 80, improvement of operation rate, and improvement of product yield. ..

The present invention has been invented in view of the above problems, and an object thereof is to provide a plasma device capable of preventing contamination of the plasma generation chamber.

[0010]

In order to achieve the above object, a plasma apparatus according to the present invention is provided with a sample holding device in a reaction chamber and an impurity deposition member, and the sample holding device is provided with a high frequency wave. In a plasma device to which a power source is connected, a changeover switch is interposed between the sample holding device and the high frequency power source, and the high frequency power source is also connected to the impurity deposition preventing member via the changeover switch. In the plasma apparatus described above, a matching circuit is interposed at least between the impurity deposition preventing member and the changeover switch.

[0011]

According to the above construction, the changeover switch is interposed between the sample holding device and the high frequency power supply, and the high frequency power supply is also connected to the impurity protection member via the changeover switch. Therefore, when removing the deposits deposited on the impurity deposition preventing member, the electrode embedded in the sample holding device is grounded, and a high frequency is applied to the impurity deposition preventing member to introduce an etching gas, By generating a plasma on the entire surface of the impurity deposition preventing member, the deposits attached to the impurity deposit preventing member are efficiently etched, and the deposits resulting from the decomposition products and reaction products of the process gas are sufficiently removed.

In the plasma device described above,
If at least a matching circuit is provided between the impurity deposition preventing member and the changeover switch, the electrode is buried in the sample holding device and the impurity deposition preventing member, and a high frequency is applied to the inside of the reaction chamber. Plasma is efficiently generated.

[0013]

Embodiments of the plasma apparatus according to the present invention will be described below with reference to the drawings. The configuration of the plasma device except for the reaction chamber 12, the periphery of the sample holding device 23, and the connection circuit for applying a high frequency to the sample holding device 23 is substantially the same as the conventional one, and the description thereof will be omitted.

In FIG. 1, reference numeral 10 designates a plasma device, and a reaction chamber wall 12a of the plasma device 10 and a side face 23a of the sample holding device 23 opposite to the sample 24 mounting face are attached to the protective coating shown in FIG. It is covered by the member 26a. Between the reaction chamber chamber wall 12a and the side surface 23a and the deposition preventing member 26a, the reaction chamber chamber wall 12a and the side surface 23a and the deposition preventing member 26a are provided.
An insulating member 27 made of Teflon, alumina, or the like is inserted as a spacer to prevent plasma from being generated between the reaction chamber 12 and the reaction chamber 12, and the deposition preventing member 26a is electrically insulated from the entire reaction chamber 12. Further, the deposition-inhibitory member 26a is configured to be grounded via the changeover switch 30a or connected to the high frequency power source 29 via the changeover switches 30a and 30c. Further, the electrode 28 embedded in the sample holding device 23 is grounded via the changeover switch 30b, or the changeover switches 30b, 3b.
It is configured to be connected to the high frequency power supply 29 via 0c.

When depositing a film on the sample 24 using the plasma apparatus 10 having the above-described structure, the deposition-preventing member 26a is grounded via the changeover switch 30a, and the sample holding device 2
The electrodes 28 embedded in the switch 3 are replaced with switches 30b, 3
A high frequency power source 29 is connected via 0c and a high frequency is applied to the electrode 28 to perform normal film formation.

On the other hand, when removing the deposits deposited on the deposition-inhibiting member 26a provided on the side wall of the reaction chamber chamber wall 12a and the sample holding device 23, the deposition-inhibiting member 26a is switched to a high frequency through the changeover switches 30a and 30c. It is connected to a power source 29 and the electrode 28 embedded in the sample holding device 23 is grounded via a changeover switch 30b. And NF ₃ , SF ₆ , CF
After introducing a fluorine-based etching gas such as ₄ or a chlorine-based etching gas such as Cl ₂ , a high frequency is applied to the deposition-inhibitory member 26a to generate plasma using the sample holding device 23 as a counter electrode to etch the deposit. At this time, the reaction chamber wall 12
a and the side surface 23a and the insulation member 27 inserted between the deposition preventing member 26a increase the discharge impedance,
Plasma is prevented from being generated between the reaction chamber chamber wall 12a and the side surface 23a and the deposition preventing member 26a.

As described above, by applying a high frequency to the deposition-inhibitory member 26a, plasma can be generated on the surface of the deposition-inhibitory member 26a, and the surface of the deposition-inhibitory member 26a can be efficiently etched by introducing the etching gas. Therefore, it is possible to completely remove the deposits attached to the deposition preventing member 26a.

Next, another embodiment of the plasma device is shown in FIG. The plasma device 40 shown in FIG. 2 is different from the plasma device 10 shown in FIG. 1 between the changeover switch 30a and the changeover switch 30c and between the changeover switch 30b and the changeover switch 30c. This is the point that the matching circuit 31 is provided.

As described above, since the deposition preventing member 26a and the electrode 28 embedded in the sample holding device 23 are connected to the high frequency power source 29 via the matching circuit 31, the deposition preventing member 26a or the sample holding device 23 can be protected. Embedded electrode 28
When a high frequency is applied to the plasma, plasma can be efficiently generated in the reaction chamber 12.

FIG. 3 shows still another embodiment of the plasma device. The plasma device 50 shown in FIG. 3 is different from the plasma device 40 shown in FIG. 2 in that the positions and shapes of the deposition-inhibitory members 26b and 26c provided in the plasma reaction chamber 12 and the gas introduction pipe 57 are different. In shape. Deposition prevention member 26b,
26c has the configuration shown in FIG. 7, has a hole 26e smaller than the outer diameter of the sample holding device 23 and larger than the outer diameter of the sample 24, and is formed in a donut shape matching the inner diameter of the reaction chamber 12. One of the deposition preventive members 26b is disposed in contact with the sample holding device 23, and the other deposition preventive member 26c is disposed closer to the plasma generation chamber 11 than the gas introduction pipe 57 and is opposed to the deposition preventive member 26b. Has been done. A gas introduction pipe 57 having a ring-shaped nozzle 57b is disposed between the deposition-inhibitory member 26b and the deposition-inhibitory member 26c and adjacent to both sides of the deposition-inhibitory member 26c facing the sample holding device 23. ing. The nozzle 57b of the gas introduction pipe 57 is formed with a hole (not shown) opened on the sample 24 side so that the gas introduced from the gas introduction pipe 57 is efficiently blown to the sample 24.

When a film is formed on the sample 24 using the plasma device 50 having the above-mentioned structure, the deposition-preventing members 26b, 2
6c is grounded via the changeover switch 30a, and the electrode 28 embedded in the sample holding device 23 is changed over to the changeover switch 3
High frequency power source 29 via 0b, 30c and matching circuit 31
Then, a normal film is formed by applying a high frequency. At this time, the plasma efficiently reaches the sample 24 through the hole 26e formed in the center of the deposition-inhibitory member 26c, and the deposition-inhibitory member 26b moves to the right of the sample holding device 23 by decomposition products or reaction products of the process gas. It plays the role of a shielding plate that prevents objects from attaching. Further, the deposition preventing member 26c also serves as a shielding plate that prevents the decomposition products and reaction products of the process gas from adhering to the inner walls of the reaction chamber 12 on the left and right sides of the deposition preventing member 26c.

On the other hand, when removing the deposits deposited on the deposition-inhibiting members 26b and 26c, the deposition-inhibiting members 26b and 26c are connected to the high-frequency power source 29 through the changeover switches 30a and 30c and the matching circuit 31, and the sample holding device is held. The electrode 28 embedded in 23 is grounded via the changeover switch 30b. Then, after introducing a fluorine-based etching gas such as NF ₃ , SF ₆ , CF ₄ or a chlorine-based etching gas such as Cl ₂ , a high frequency is applied to the deposition-inhibitory members 26b and 26c, and plasma is generated using the sample holding device 23 as a counter electrode. generate.

As described above, by applying a high frequency to the deposition-inhibiting members 26b and 26c, plasma can be generated on the surfaces of the deposition-inhibiting members 26b and 26c. It will be efficiently etched, and the deposition preventing members 26b and 26c
It is possible to completely remove the deposits attached to the surface.
Further, since the deposition preventing members 26b and 26c and the electrode 28 embedded in the sample holding device 23 are connected to the high frequency power source 29 through the matching circuit 31, the deposition preventing members 26b and
When applying a high frequency to the electrode 6c or the electrode 28 embedded in the sample holding device 23, plasma can be efficiently generated in the reaction chamber 12.

FIG. 4 shows still another embodiment of the plasma device. The plasma device 60 shown in FIG. 4 differs from the plasma device 40 shown in FIG. 2 in that the plasma reaction chamber 1
The positions and shapes of the deposition-inhibitory members 26b and 26d installed in the second item and the shape of the gas introduction pipe 67 are shown. A doughnut-shaped deposition preventive member 26b having a hole 26e smaller than the outer diameter of the sample holding device 23 and larger than the outer diameter of the sample 24 and abutting the inner diameter of the reaction chamber 12 contacts the sample holding device 23. And the horn-shaped deposition preventing member 26 shown in FIG.
d extends from the plasma extraction window 18 to the vicinity of the sample holding device 23. One end of the deposition preventive member 26d has an outer diameter slightly larger than that of the plasma extraction window 18 and is connected to the outer peripheral portion of the plasma extraction window 18, and the other end has an outer diameter slightly larger than that of the sample holding device 23. , And is connected to the deposition-inhibitory member 26b arranged in the vicinity of the sample holding device 23. In addition, a hole 26 is formed in the horn-shaped deposition preventing member 26d so that the entire reaction chamber 12 can be vacuumed.
f is formed. Further, the horn-shaped deposition preventing member 26
A gas introducing pipe 67 having a ring-shaped nozzle 67b is provided at a position facing the sample holding device 23 inside d, and the nozzle 67b of the gas introducing pipe 67 is disposed.
A hole (not shown) is formed in this so that the gas introduced from the gas introduction pipe 67 can be efficiently blown to the sample 24.

When a film is formed on the sample 24 by using the plasma device 60 having the above structure, the deposition-preventing members 26b, 2
6d is grounded via the changeover switch 30a, and the electrode 28 embedded in the sample holding device 23 is changed over to the changeover switch 3
High frequency power source 29 via 0b, 30c and matching circuit 31
Then, high frequency is applied to perform normal film formation. At this time, the plasma efficiently reaches the sample 24 through the inside of the deposition preventing member 26d, and the deposition preventing member 26d prevents the decomposition products and reaction products of the process gas from adhering to the inner wall surface of the reaction chamber 12. Plays the role of a shielding plate. Further, the deposition preventive member 26b plays a role of a shielding plate that prevents the decomposition products and reaction products of the process gas from adhering to the right side of the sample holding device 23.

On the other hand, when removing the deposits deposited on the deposition-inhibiting members 26b and 26d, the deposition-inhibiting members 26b and 26d are connected to the high-frequency power source 29 through the changeover switches 30a and 30c and the matching circuit 31, and the sample holder is held. The electrode 28 embedded in 23 is grounded via the changeover switch 30b.
Fluorine-based materials such as NF ₃ , SF ₆ , CF ₄ or C
After introducing a chlorine-based etching gas such as l ₂ or the like, a high frequency is applied to the deposition preventing members 26b and 26d to apply the sample holding device 23.
Plasma is generated using the as a counter electrode.

As described above, by applying a high frequency to the deposition-inhibiting members 26b and 26d, plasma can be generated on the surfaces of the deposition-inhibiting members 26b and 26d. It will be efficiently etched, and the deposition preventing members 26b and 26d will be etched.
It is possible to completely remove the deposits attached to the surface.
Further, since the deposition preventing members 26b and 26d and the electrode 28 embedded in the sample holding device 23 are connected to the high frequency power source 29 through the matching circuit 31, the deposition preventing members 26b and
When applying a high frequency to 6d or the electrode 28 embedded in the sample holding device 23, plasma can be efficiently generated in the reaction chamber 12.

The plasma devices 10, 40, and
Adhesion-preventing member 26 installed inside the reaction chamber 12 of 50 and 60
a, 26b, 26c and 26d are aluminum base material or titanium base material made of Si to prevent corrosion due to etching gas.
The one with O ₂ coating is used. In the plasma devices 50 and 60 described above, the sample holding device 2
3, the electrodes 28 and the deposition preventing members 26b, 26c embedded in
26d is connected to the high-frequency power source 29 via the matching circuit 31, but the matching circuit 31 may not be provided.

[0029]

As described in detail above, in the plasma device according to the present invention, the sample holding device is arranged in the reaction chamber and the impurity adhesion preventing member is internally provided, and the sample holding device is provided with the high frequency power source. In the connected plasma device, a change-over switch is interposed between the sample holding device and the high-frequency power source, and the high-frequency power source is also connected to the impurity deposition preventing member via the change-over switch. When removing the deposits deposited on the impurity deposition prevention member,
By grounding the electrode buried in the sample holding device and applying a high frequency to the impurity-preventing member, plasma can be generated over the entire surface of the impurity-preventing member, and the impurity-preventing member can be protected by introducing an etching gas. By efficiently etching the surface of the member, it is possible to sufficiently remove the deposits due to the decomposition products and reaction products of the process gas adhered to the surface of the impurity deposition preventing member. Therefore, it is possible to improve the operating rate of the plasma device and the product yield due to stable operation.

Further, in the plasma device described above,
When a matching circuit is provided at least between the impurity protection member and the changeover switch, the reaction chamber is applied to the electrode embedded in the sample holding device and the impurity protection member when applying a high frequency. It becomes possible to efficiently generate plasma.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a plasma device according to the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the plasma device.

FIG. 3 is a schematic sectional view showing still another embodiment of the plasma device.

FIG. 4 is a schematic sectional view showing still another embodiment of the plasma device.

FIG. 5 is a schematic sectional view showing a conventional plasma device.

FIG. 6 is a perspective view showing an attachment preventing member.

FIG. 7 is a perspective view showing another deposition preventing member.

FIG. 8 is a perspective view showing still another deposition preventing member.

[Explanation of symbols]

 10, 40, 50, 60 Plasma device 12 Reaction chamber 23 Sample holding device 26a, 26b, 26c, 26d Deposition member 29 High frequency power source 30a, 30b, 30d Changeover switch 31 Matching circuit

Front page continuation (72) Inventor Yoshitaka Morioka 1-3-3 Otemachi, Chiyoda-ku, Tokyo Sumitomo Metal Industries, Ltd. (72) Inventor Masashi Tano 1-3-1 Otemachi, Chiyoda-ku, Tokyo Sumitomo Metal Industries, Ltd.

Claims (2)

[Claims] 1. A plasma apparatus in which a sample holding device is disposed in a reaction chamber, an impurity deposition preventing member is internally provided, and a high frequency power source is connected to the sample holding device, the sample holding device and the high frequency power source are connected to each other. A plasma device in which a changeover switch is interposed between the impurity protection member and the high-frequency power source is also connected via the changeover switch. 2. The plasma apparatus according to claim 1, wherein a matching circuit is provided at least between the impurity deposition preventing member and the changeover switch.