JPH0621003A - Plasma processor - Google Patents

Abstract

PURPOSE:To effectively prevent the leakage of electromagnetic waves from the window for monitoring by equipping a processor with a monitoring window for monitoring the emitted light of plasma by transmitting it to outside and an electromagnetic shield. CONSTITUTION:A monitoring window hole 38 is positioned at the side of a process chamber 10, and it is formed in the shape of, for example, a circle in the vicinity of the height of plasma generated. And, a monitoring window 40 is provided in the position of this monitoring window 38. The monitoring window 40 is one for transmitting the emitted light of plasma generated in the process chamber 10, and it is equipped with a translucent member 24, a holder member 44, and an electromagnetic shield 50. In the electromagnetic shield 50, a transmission hole for plasma generation is secured since it is made in porous or mesh shape. Hereby, the electromagnetic waves generated in a processing chamber can be effectively prevented from leaking to outside.

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 having an electromagnetic wave shield provided on a plasma emission monitor window.

[0002]

2. Description of the Related Art For example, in a parallel plate type plasma etching apparatus which is one of semiconductor device manufacturing apparatuses, a plasma is formed by applying a high frequency RF power supply between parallel electrodes, and a wafer is etched by this plasma. It is carried out.

By the way, in this type of apparatus, it is indispensable to detect the end point of the plasma processing and monitor the progress of the plasma processing for the subsequent operation. Therefore, a translucent monitor window is provided in the process chamber in which plasma is generated, and a plasma processing end point detection device (EPD) is provided facing the monitor window. Then, the plasma emission intensity is detected by this EPD, and the emission intensity in the steady state of plasma is 10
When it is set to 0%, the point at which this is reduced to 60% is detected as the plasma processing end point.

Further, by using this monitor window portion, for example, the emission spectrum intensity of plasma in the apparatus is detected,
A plasma processing apparatus has also been proposed that can control a plasma state by controlling a parameter group for generating plasma based on the emission spectrum intensity.

[0005]

By the way, since such a monitor window is made of quartz glass or the like, it transmits the emission spectrum of plasma and also the electromagnetic waves generated in the processing apparatus. . Therefore, for example, in the parallel plate type plasma processing apparatus, 13.56 MHz and 40 MH generated by the RF power source added between the parallel plates.
A large amount of electromagnetic waves such as high frequencies such as z and harmonics of these high frequencies leak from the monitor window. It has been found that the leaked electromagnetic waves have various adverse effects such as malfunctions on various devices outside the process chamber.

This is shown in FIG. FIG. 5 is a schematic explanatory view showing an example of the plasma processing apparatus. In the figure, a process chamber 10 for performing processing such as wafer etching is provided, and load locks for loading and unloading wafers to be processed into and out of the process chamber 10 on both sides of the process chamber 10. A chamber 72 and an unload lock chamber 74 are arranged via a gate valve. Further, the process window 10 is provided with the above-mentioned monitor window portion 40, and the detection system 82 for detecting the emission spectrum of the plasma transmitted through the monitor window portion 40 is arranged. Incidentally, reference numerals 84 and 8
Reference numeral 6 is a power supply system of the apparatus, and reference numerals 88 and 90 are sensor systems of the apparatus. Reference numeral 92 denotes an operation system of this device, which incorporates various boards for operating and controlling the device.

In such a plasma processing apparatus, the high frequency electromagnetic wave leaked from the monitor window 40 as described above is used for the operation and control built in the sensor systems 88 and 90 and the operation system 92. It propagates to the substrate as noise, which is a major cause of malfunction of the device. Further, this electromagnetic wave also propagates as noise on the signal wiring between the operation system 92 and the power supply systems 84 and 86, for example, causing malfunctions and the like.

Further, the leaked high-frequency electromagnetic wave also acts as noise on the emission spectrum of the plasma detected by the detection system 82. This state is schematically shown in FIG. FIG. 5 is a characteristic diagram showing a temporal change in the plasma emission intensity at a specific wavelength in the emission spectrum input to the EPD. As described above, the end point of the plasma processing is detected by setting the emission intensity in the steady state of the plasma to 1
When it is set to 00% (time t1), the point (time t2) at which it decreases to 60% is detected as the plasma processing end point. However, in the emission spectrum of this plasma, as shown in the figure, the high-frequency electromagnetic wave leaked from the monitor window 40 becomes noise. Therefore, the end point position of plasma processing may be erroneously detected before the emission intensity is reduced to 60%, which causes variations in processing of the object to be processed.

Further, a substance generated by plasma adheres to the inner surface of the monitor window 40 on the process chamber 10 side every time plasma processing is performed. As a result, the absolute value of the emission spectrum intensity of the detected plasma is relatively lowered each time the processing is performed, and moreover, the plasma emission of the EPD cannot be monitored frequently. .

Therefore, an object of the present invention is to provide a plasma processing apparatus capable of effectively preventing the leakage of electromagnetic waves from the monitor window portion.

[0011]

To achieve the above object, a plasma processing apparatus according to a first aspect of the present invention is a plasma processing apparatus for introducing a processing gas into a processing chamber to generate plasma to process an object to be processed. A monitor window portion provided in the processing chamber for transmitting the plasma emission to the outside for monitoring, and a monitor formed by forming a porous or mesh shape with a conductive material provided in the monitor window portion. An electromagnetic wave shield that shields electromagnetic waves leaking from the window portion.

According to a second aspect of the present invention, in a plasma processing apparatus for introducing a processing gas into a processing chamber to generate plasma to process an object to be processed, the plasma processing apparatus is provided in the processing chamber, and the plasma emission is externally provided. Leakage from the monitor window portion, which is provided through the monitor window portion through which the light is transmitted and the monitor window portion, which is a heating element and a conductive material, and which is porous or mesh-shaped. An electromagnetic wave shield for shielding an electromagnetic wave, and an energizing means for energizing the electromagnetic wave shield are provided.

According to a third aspect of the present invention, in a plasma processing apparatus for introducing a processing gas into the processing chamber to generate plasma to process an object to be processed, the plasma processing apparatus is provided in the processing chamber, and the plasma emission is externally provided. It is characterized in that it is provided with a monitor window portion for transmitting and monitoring, and an electromagnetic shield glass provided on the monitor window portion.

[0014]

According to the first to third aspects of the present invention, the plasma emission of the plasma generated in the processing chamber is provided in the processing chamber for detecting the plasma processing end point and controlling the plasma state. It can be transmitted through the window.

According to the first aspect of the invention, the monitor window is provided with a porous or mesh electromagnetic wave shield. Therefore, the plasma emission transmitted through the monitor window can be transmitted as it is through the porous or mesh holes of the electromagnetic wave shield. Thus, even though the electromagnetic wave shield can transmit the plasma emission as described above, since the material is formed of the conductive material, it is possible to effectively prevent the electromagnetic wave generated in the processing chamber from leaking to the outside of the processing chamber. Can be prevented.

In the second aspect, the electromagnetic wave shield can be energized by the energizing means. Thereby, the electromagnetic wave shield can be heated, and the monitor window portion provided with the electromagnetic wave shield can be heated. As a result, it is possible to effectively remove the substance adhering to the monitor window.

According to the third aspect of the invention, the high transparency and the high electromagnetic wave shielding effect are imparted to the monitor window portion for plasma emission. Therefore, the electromagnetic waves generated in the processing chamber can be effectively prevented from leaking to the outside.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a parallel plate type plasma etching apparatus will be specifically described below with reference to the drawings.

First, the outline of the parallel plate type plasma etching apparatus will be described with reference to FIG.

In the figure, a wafer 20 can be placed and moved up and down inside a process chamber 10 in which a gas exhaust hole 14 can be evacuated and an etching gas can be introduced through a gas introduction hole 12. Lower mounting electrode 2
Two are provided. Here, the process chamber 10
Is made of, for example, a highly conductive aluminum material, and an upper electrode 16 made of, for example, a highly conductive aluminum material is provided on the inner upper portion thereof.

A bellows 2 is provided below the lower mounting electrode 22.
4 is provided, the interior of the process chamber 10 can be kept airtight from the outside atmosphere even if the lower placement electrode 22 is moved up and down in order to set the inter-electrode distance to a predetermined value.
In addition, the lower mounting electrode 22 has a frequency of, for example, 13.5.
R that outputs high frequency power of 6MHz or 40MHz
F power source 26 is connected to the process chamber 1 while
The upper electrode 16 provided at 0 is grounded to form a cathode coupling (RIE) parallel plate electrode. Therefore, by turning on the RF power source 26 and introducing the process gas, plasma can be generated facing the wafer 20 between the parallel plate electrodes.

In this embodiment, the upper electrode 16 is provided with a plurality of gas ejection holes 18. Therefore, the plasma generation gas introduced from the gas introduction hole 12 is uniformly ejected from the plurality of gas ejection holes 18, and uniform plasma can be stably generated below the upper electrode 16.

As shown in FIG. 2, a monitor window hole 38
Is a side surface portion of the process chamber 10 and is formed, for example, in a circular shape near a height position where plasma is generated. The monitor window portion 40 is provided at the position of the monitor window hole 38 as shown in FIG.

The monitor window 40 is for transmitting the plasma emission of the plasma generated in the process chamber 10, and is provided with a translucent member 42, a holder member 44, and an electromagnetic wave shield 50.

The translucent member 42 is formed of a member capable of transmitting the wavelength of plasma emission, such as quartz glass. In particular, the inner surface 41 of the translucent member 42 has a process chamber 10 in which plasma processing is performed at high temperature.
Since it is exposed to the inner side surface of the, it is desirable to form it with a material that has heat resistance and does not easily cause contamination. The translucent member 42 is formed, for example, in a cylindrical shape having a stepped surface 42a, the side surface of the tip end portion thereof is processed so as to fit into the monitor window hole 38, and is fitted into the monitor window hole 38. At this time, a groove for O-ring is provided on either one of the process chamber 10 or the stepped surface 42a of the transparent member 42, and the O-ring 47 is interposed to secure the airtightness. Furthermore, in this case, the inner surface 4 of the translucent member 42
1 is preferably formed so as to be flush with the inner surface of the process chamber 10. Process chamber 10
This is because if there is unevenness on the inner side surface, abnormal discharge may occur and interfere with stable plasma generation.

The outer surface 43 of the translucent member 42 is in contact with an electromagnetic wave shield 50 formed in a disk shape, for example.
An insulating holder member 44 having a window hole 45 corresponding to the monitor window hole 38 is provided outside the electromagnetic wave shield 50. The holder member 4
4 is fixed to the outer wall of the process chamber 10 by screws 46, for example. Therefore, the electromagnetic wave shield 50 is fixed by pressing the peripheral portion thereof with the translucent member 42 and the insulating member 44.

The electromagnetic wave shield 50 is, for example, a nichrome wire (Ni-Cu), or iron (Fe) and chromium (Cr).
And a transmission hole having a diameter of, for example, about 5 to 10 mm is formed in a porous or mesh shape by Kanthal (trade name) which is an alloy wire of aluminum and aluminum (Al). And
A connection terminal 52 is provided at one end of the electromagnetic wave shield 50, and is connected to a crimp terminal 54 provided in the grounded process chamber 10. As a result, the electromagnetic wave shield 5
0 will be grounded. Also, the electromagnetic wave shield 50
A connection terminal 56 is further provided at the other end of the connection terminal 56, and the connection terminal 56 is connected to the DC power supply 58. As a result, the electromagnetic wave shield 50 can be energized.

The electromagnetic wave shield 50 is formed in a porous shape or a mesh shape to secure a transmission hole for plasma generation. As described above, the electromagnetic wave shield is formed of a grounded conductive material such as a nichrome wire or Kanthal as described above, although the electromagnetic wave shield can transmit plasma emission. ,
It is possible to effectively prevent leakage to the outside of the processing chamber. In particular, since Fe and Ni are ferromagnetic materials, they are suitable materials for the electromagnetic wave shield.

In this embodiment, this electromagnetic wave shield 50 is used.
Not only as a means to prevent electromagnetic wave leakage,
It is also used as a heating means for the monitor window 40. The heating means is provided to prevent the gas generated by the generation of plasma, for example, CF4 which is a fluorine-based gas, from adhering to the inner surface 41 of the transparent member 42. When such a substance adheres to the film, the translucent member 4
The transmittance of No. 2 decreases, and the absolute value of the plasma emission intensity input to the detection system outside the monitor window 40 decreases. If the absolute value of the detected plasma emission intensity decreases, the noise margin with respect to the detected value decreases, which increases the probability that the detection system will malfunction. In particular, if the plasma processing apparatus having such a window for monitoring is used many times, the amount of the substance attached to the film increases with time, and finally the detection by the detection system becomes impossible. There was a situation where it became impossible.

In this way, the removal of the substance adhered to the film was conventionally performed during the maintenance of the process tube 10. In this embodiment, by providing a heating means in the monitor window portion 40 and heating the translucent member 42,
It prevents such substances from adhering to the film. Particularly, in this embodiment, since the electromagnetic wave shield 50 is also used as the heating means, it is not necessary to newly provide a device for heating. That is, in the present embodiment, as described above, the DC power source 58 is configured so that the electromagnetic wave shield 50 can be energized toward the grounded process tube 10. Moreover, as the material for forming the electromagnetic wave shield 50, the most suitable material for the heating wire, which has a high resistivity, such as nichrome wire or Kanthal is used. Accordingly, the electromagnetic wave shield 50 can be effectively used as a heater for the translucent member 42 by using the DC power source 58 to energize the electromagnetic wave while preventing the electromagnetic wave from leaking.

The heating temperature of the translucent member 42 in this case is optimally 140 to 160 ° C. in order to effectively prevent the film deposition by the fluorine-based gas such as CF4.

As described above, according to this embodiment, it is possible to effectively prevent the leakage of electromagnetic waves generated in the process chamber 10 and also effectively prevent the film from adhering to the inner side surface 41 of the translucent member 42. . As a result, when the present embodiment is applied to the device shown in FIG. 6, it is possible that electromagnetic waves leaked from the monitor window 40 propagate as noise to the substrates, wirings, etc. incorporated in the sensor systems 88 and 90, the operation system 92. It can be effectively prevented, and the malfunction of the device can be prevented. Further, for example, the detection system 82 is a plasma processing end point detection device (E
PD), the leaked electromagnetic wave becomes noise as shown in FIG.
Propagation on the plasma emission spectrum can be effectively prevented as shown in FIG. Therefore, it is possible to effectively prevent a situation in which the plasma processing end point is detected and the device malfunctions before reaching t2 in FIG. 5, for example. In this respect, in the present embodiment, since the electromagnetic wave shield 50 is also used as the heater for preventing the film adhesion, the absolute value of the emission spectrum intensity decreases due to the film adhesion, which effectively eliminates the noise margin. It can be prevented. Therefore, it becomes possible to prevent the malfunction of the device more effectively.

FIG. 3 shows a second embodiment of this embodiment. In this modification, the central portion of the electromagnetic wave shield 50 is provided with a porous or mesh-shaped transmission hole and a transmission central hole 60 having a diameter larger than the diameter of these transmission holes. This makes it possible to detect the plasma emission by the detection system 30 and the condenser lens 32 more reliably.

FIG. 4 shows a third embodiment. The same parts as those in FIGS. 2 and 3 are designated by the same reference numerals and the description thereof will be omitted.

The electromagnetic wave shielding glass has a structure in which a polyester net 100 plated with a conductive metal such as nickel or aluminum is sandwiched between two intermediate films 102 and 102 made of a colorless transparent polymer resin. The monitor window has a structure in which the electromagnetic wave shielding glass is sandwiched by quartz glass 42 and 104 from both sides.

The function of this electromagnetic wave shielding glass is that it has both high transparency and a high electromagnetic wave shielding effect. Regarding the transparency, the plasma emission in the process chamber 10 can be visually recognized in the visible light region through the monitor window 40, and a sufficient transmitted light amount to monitor the plasma emission including the region outside the visible light region can be obtained. To be Regarding the electromagnetic wave shield, there is a shield effect of 40 dB or more in the entire region of the MHZ band in the electric field / plane wave. Particularly, 13.56 MHZ and 4 output from the RF power source 26 used in the semiconductor manufacturing apparatus
There is a high shielding effect for high frequencies of 0 MHZ and harmonics of these high frequencies.

Further, according to the electromagnetic wave shielding glass, since the conductive net is sandwiched between the two colorless and transparent intermediate films, there is no possibility of causing secular change of the metal net due to oxidation.

As another embodiment, an electromagnetic wave shielding glass can be constructed by coating a quartz glass window used for the monitor window portion 40 with tin oxide (SnO ₂ ) by the CVD method.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist of the present invention.

The plasma processing apparatus to which the present invention is applied is not limited to the parallel plate type plasma etching apparatus described above, but may be another type of plasma etching apparatus. Therefore, for example, an ECR etching device, a reactive ion etching device, or a magnetic field assisted magnetron etching device that forms orthogonal electric fields and magnetic fields to generate plasma may be used. Furthermore, the type of processing is not limited to etching, and the same can be applied to other plasma processing apparatuses such as a film forming apparatus such as CVD, a sputtering apparatus, and an ashing apparatus.

Further, in this embodiment, when the electromagnetic wave shield 50 is also used as a heater, the holder member 44 is formed of an insulating member, but when the electromagnetic wave shield 50 is not also used as a heater, the holder member 44 is not necessarily required. It does not have to be an insulating member. Furthermore, when the electromagnetic wave shield 50 is not also used as a heater, the holder member may be made of a metal that has a low heat generation effect by energization, or at least a material that can shield the electromagnetic wave.

[0042]

As described above, according to the invention of claim 1, the monitor window portion and the electromagnetic wave shield allow the plasma emission of the plasma generated in the processing chamber to pass through the porous or mesh-shaped transmission holes. Because it can be transmitted,
The electromagnetic waves generated in the processing chamber can be effectively prevented from leaking to the outside. Therefore, it is possible to effectively prevent an external device or the like from malfunctioning due to this electromagnetic wave, or a false detection of plasma emission.

Further, in the invention of claim 2, since the electromagnetic wave shield is also used as a heater, the substance adhered to the monitor window can be effectively removed. Therefore, it is possible to effectively prevent a situation in which the detection becomes impossible due to the film adhesion over time.

According to the third aspect of the invention, since the high translucency and the high electromagnetic wave shielding effect can be imparted to the plasma emission monitor window portion, the electromagnetic wave generated in the processing chamber leaks to the outside. Can be effectively prevented. Therefore, it is possible to effectively prevent an external device or the like from malfunctioning due to this electromagnetic wave, or a false detection of plasma emission.

[Brief description of drawings]

FIG. 1 is a schematic explanatory diagram for explaining a monitor window portion of a parallel plate plasma processing apparatus that is an embodiment of the present invention.

FIG. 2 is a schematic explanatory view of a parallel plate type plasma processing apparatus which is an embodiment of the present invention.

FIG. 3 is a schematic explanatory view showing a second embodiment of the present invention.

FIG. 4 is a schematic explanatory view showing a third embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a temporal change in the emission intensity of plasma input to the plasma processing end point detection device.

FIG. 6 is a schematic explanatory view showing an example of an arrangement of devices outside a process chamber.

[Explanation of symbols]

 10 Process Chamber 16 Upper Electrode 20 Wafer 22 Lower Placed Electrode 26 RF Power Source 40 Monitor Window 42 Translucent Member 50 Electromagnetic Wave Shield 58 DC Power Source 60 Transparent Central Hole 100 Polyester Net 102 Intermediate Film 104 Quartz Glass

Claims (3)

[Claims] 1. A plasma processing apparatus for introducing a processing gas into a processing chamber to generate plasma to process an object to be processed, the monitor being provided in the processing chamber and transmitting the plasma emission to the outside for monitoring. A window portion; and an electromagnetic wave shield that is provided in the monitor window portion and that shields electromagnetic waves leaking from the monitor window portion by forming the conductive material into a porous or mesh shape. Plasma processing apparatus. 2. A plasma processing apparatus for introducing a processing gas into a processing chamber to generate plasma to process an object to be processed, the monitor being provided in the processing chamber and transmitting the plasma emission to the outside for monitoring. A window portion, an electromagnetic wave shield provided in the monitor window portion, which is a heating element and a conductive material, and which shields an electromagnetic wave leaking from the monitor window portion by forming a porous or mesh shape, A plasma processing apparatus comprising: an energizing unit that energizes the electromagnetic wave shield. 3. A plasma processing apparatus for introducing a processing gas into a processing chamber to generate plasma to process an object to be processed, the monitor being provided in the processing chamber and transmitting the plasma emission to the outside for monitoring. A plasma processing apparatus comprising: a window portion; and an electromagnetic shield glass provided on the monitor window portion.