JPH07122543A - Control method for plasma etching system - Google Patents

Abstract

PURPOSE:To improve the etching profile by observing the emission intensity ratio between a gas component the volume of which in the processing chamber varies significantly and a gas component the volume of which does not vary significantly at the time of etching and then controlling the high frequency energy being applied to a high frequency antenna. CONSTITUTION:An optical sensor 36 observes a signal representative of the emission spectrum of a first gas component the volume of which in the processing chamber varies relatively at the time of etching. A signal representative of the emission spectrum of a second gas component the volume of which in the processing chamber does not vary relatively is also observed. A controller 37 determines the emission intensity ration of the emission spectrum between two types of gas component. High frequency energy being applied to a high frequency antenna is then subjected to feedback control depending on the variation in the emission intensity ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a plasma etching processing apparatus.

[0002]

2. Description of the Related Art Conventionally, a parallel plate type plasma processing apparatus using a high frequency (RF) has been widely adopted as an apparatus for plasma processing an object to be processed such as a semiconductor wafer in a processing chamber. Reactive ion etching (R) in which two parallel plate type electrodes are arranged in the processing chamber
IE) In the example, by applying a high frequency to either one or both electrodes, a plasma is generated between both electrodes, and the self-bias potential difference between the plasma and the object to be processed causes A plasma flow is made incident on the processing surface of the object to be processed to perform etching processing.

However, in a conventional plasma processing apparatus such as the above parallel plate type plasma processing apparatus, sub-micron unit, further sub-half-micron unit ultra-fine processing, which is required in accordance with ultra-high integration of semiconductor wafers. Is difficult to implement. In other words, in order to carry out such a process with a plasma processing apparatus, it is important to control high-density plasma with high accuracy in a low-pressure atmosphere, and the plasma has a large area that is compatible with large-diameter wafers. It must be highly uniform. Further, in a plasma processing apparatus using an electrode, the electrode itself becomes a source of heavy metal contamination when plasma is generated, which is a problem particularly when ultrafine processing is required.

In response to such technical requirements, many approaches have been taken from various angles to establish a new plasma source, for example, in European Patent Publication No. 379828. A high frequency induction plasma generator using a high frequency antenna is disclosed. In this high-frequency induction plasma generator, one surface of the processing chamber facing the wafer mounting table is made of an insulating material such as quartz glass, and a high-frequency antenna composed of, for example, a spiral coil is attached to the outer wall surface of the processing chamber. Is applied to form a high-frequency electromagnetic field in the processing chamber, electrons flowing in the electromagnetic field space are caused to collide with neutral particles of the processing gas, and the gas is ionized to generate plasma.

[0005]

By the way, when the above-mentioned high frequency induction plasma is used to etch a silicon oxide film, for example, with a CF type processing gas, the object to be etched is removed at a high etching rate. At the same time, it is necessary to accurately form the etching shape in a vertical or substantially tapered shape, and for that purpose, it is essential to establish a technique for controlling the starting point and the ending point of etching with high accuracy.

The present invention has been made in view of the above problems that occur when an etching process is performed by a high frequency induction type plasma processing apparatus, and an object of the present invention is to provide a high frequency induction type plasma processing. It is an object of the present invention to provide a new and improved control method for ensuring a good etching shape at a high etching rate when performing an etching process with an apparatus.

[0007]

In order to solve the above-mentioned problems, a control method of a plasma etching processing apparatus constructed according to the first aspect of the present invention is arranged outside a processing chamber via an insulator. In controlling the plasma etching processing device that excites induction plasma in the processing chamber by applying high-frequency power to the high-frequency antenna, and performs etching processing on the object to be processed placed in the processing chamber, The emission intensity ratio between the first gas component whose amount present in the processing chamber changes relatively greatly and the second gas component whose amount present in the processing chamber does not relatively change during the etching process is observed, It is characterized in that the high frequency energy applied to the high frequency antenna is controlled according to the variation of the emission intensity ratio.

Further, in the control method of the plasma etching processing apparatus constructed according to the second aspect of the present invention, high frequency power is applied to a high frequency antenna arranged outside the processing chamber through an insulator. In controlling the plasma etching apparatus that excites induction plasma in the processing chamber and performs etching processing on the object to be processed placed in the processing chamber, etching processing is performed on a dummy wafer placed in a predetermined etching atmosphere. The correlation between the pressure in the processing chamber and the etching rate at that time is obtained in advance, the pressure range in which the etching rate falls within a predetermined value range is determined in advance, and in the actual etching process, the pressure in the processing chamber is set to Observe and control the exhaust gas volume while controlling the exhaust volume so that the pressure is within the above pressure range. It is characterized by applying quenching process.

[0009]

According to the first aspect of the present invention, the first gas component in which the amount present in the processing chamber during the etching process changes relatively greatly, for example, the first gas component which reacts with the etching target such as an oxide film during the etching process, causes the inside of the processing chamber. However, the detected emission intensity remains at a low level.
When the etching is completed, it is not consumed and the amount thereof is increased, and thus the detected emission intensity is increased, for example, a CF-based processing gas such as CF or CF ₂ or, conversely, etching is performed. At times, a reaction product that reacts with an etching object such as an oxide film and is actively generated, and thus the detected emission intensity increases, but is not generated when etching is completed, and thus the detected emission intensity decreases. For example, the emission intensity of CO gas and a second gas component whose amount present in the processing chamber does not fluctuate relatively during etching, for example, an inert gas such as argon or nitrogen mixed for plasma stabilization. The emission intensity ratio reflects the plasma state in the processing chamber in real time. Flip and, by feedback control of the high-frequency energy to be applied to the high frequency antenna,
It is possible to maintain the plasma state in the processing chamber to be optimum, and particularly to precisely control the end point of etching. In addition,
As a method of controlling the high frequency energy, it is possible to adopt a method of increasing or decreasing the high frequency power itself, or a method of adjusting the magnitude, frequency, phase, or amplitude of the high frequency energy via a matching box or the like.

According to the second aspect of the present invention, as a result of observing the correlation between the gas pressure in the processing chamber and the etching rate, attention is paid to the fact that the etching is stable at a high etching rate in a predetermined pressure range, and dummy wafers are previously prepared. By determining the processing pressure range that can obtain the optimum etching rate by observing only the pressure fluctuation in the processing chamber during actual processing and controlling it so that it is within the pressure range obtained in advance, the etching processing is performed. It becomes possible to carry out stable etching at a high etching rate.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a method for controlling a plasma etching processing apparatus constructed according to the present invention will be described in detail below with reference to the accompanying drawings.

The plasma etching apparatus 1 shown in FIG.
The processing container 2 is made of a conductive material, such as aluminum, and is formed into a cylindrical or rectangular shape. The processing container 2 has a bottom portion via an insulating plate 3 made of ceramic or the like to be processed, such as a semiconductor. A substantially columnar mounting table 4 for mounting the wafer W is housed. The top of the processing container, which is substantially opposite to the mounting surface of the mounting table 4, has an insulating material 5,
For example, it is made of quartz glass or ceramic, and a conductor such as a copper plate, aluminum, or the like is attached to the outer wall surface of the insulating material 5.
A high frequency antenna 6 formed of a spiral coil such as stainless steel is arranged. Between both terminals (inner terminal 6a and outer terminal 6b) of the high frequency antenna 6, it is possible to apply high frequency energy of, for example, 13.56 MHz from a high frequency power source 7 for plasma generation through a matching circuit 8. Is configured.

A mounting table 4 for mounting a processing object W such as a semiconductor wafer is provided on a susceptor supporting table 4a formed of aluminum or the like in a columnar shape, and is detachably provided on the susceptor supporting table 4a by bolts 4b or the like. It is mainly composed of a susceptor 4c made of aluminum or the like. By making the susceptor 4c detachable in this manner, maintenance and the like can be easily performed.

The susceptor support 4a has a cooling means,
For example, a cooling jacket 9 is provided, and a coolant such as liquid nitrogen is supplied to the jacket 9 as a coolant source 10.
It is introduced through the refrigerant introduction pipe 11. Further, the liquid nitrogen that circulates in the jacket and is vaporized by the heat exchange action is discharged from the refrigerant discharge pipe 12 to the outside of the container. With this configuration, cold heat of liquid nitrogen at, for example, −196 ° C. is transferred from the cooling jacket 9 to the semiconductor wafer W via the susceptor 4c, and the processing surface can be cooled to a desired temperature.

Further, an electrostatic chuck 12 is formed on the wafer mounting portion on the upper surface of the susceptor 4c formed in a substantially columnar shape so as to have an area substantially the same as the wafer area. This electrostatic chuck 12 is formed, for example, by sandwiching a conductive film 13 such as a copper foil in an insulating state between two polymer polyimide films, and the conductive film 13 is connected to a variable DC high-voltage power supply 14 by a lead wire. ing. Therefore, this conductive film 13
By applying a high voltage to the electrostatic chuck 1,
The semiconductor wafer W can be adsorbed and held on the upper surface of 2 by Coulomb force.

The susceptor support base 4a and the susceptor 4
c is a gas passage 16 for penetrating these and supplying a heat transfer gas (back cooling gas) such as He from the gas source 15 to the back surface of the semiconductor wafer W or the joint portion of each member constituting the susceptor 4c. Are formed. An annular focus ring 17 is arranged on the upper edge of the susceptor 4c so as to surround the semiconductor wafer W.
The focus ring 17 is made of a high resistance material that does not attract reactive ions, for example, ceramic or quartz glass, and acts so that the reactive ions are effectively incident only on the semiconductor wafer W inside.

Further, a high frequency power source 19 is connected to the susceptor 4c via a matching capacitor 18, and a high frequency power of, for example, 2 MHz is applied to the susceptor 4c at the time of processing so that a bias potential is generated between the susceptor 4c and the plasma. It is possible to effectively generate and irradiate the surface of the object to be processed with the plasma flow. The susceptor 4c
A gas supply means 20 made of quartz glass, ceramics, or the like is arranged above. The gas supply means 20 has a hollow disk shape having substantially the same area as the mounting surface of the susceptor 4c, and the upper portion thereof penetrates substantially the center of the insulating material 5 and has a hollow portion of the gas supply means 20. A gas supply pipe 21 communicating with is attached. A large number of small holes 23 are formed in the lower surface 22 of the gas supply means 20 so that the etching gas is uniformly blown into the processing space below. Further, in the hollow portion of the gas supply means 20,
A protrusion 25 protruding toward the gas supply pipe 21 at the center
Is provided so as to promote the mixing of the etching gas supplied from the gas sources 27a and 27b through the mass flow controller 28, and to blow out the gas into the processing chamber at a more uniform flow rate. Is configured. Furthermore, an annular projection 29, which acts so as to concentrate the gas on the processing surface of the object to be processed, is attached downward around the lower surface 22 of the gas supply means 20.

An exhaust pipe 30 is connected to the bottom wall of the processing container 2 so that the atmosphere in the processing container 2 can be exhausted by an exhaust pump (not shown), and the central side wall is provided. A gate valve (not shown) is provided, and the semiconductor wafer W is loaded and unloaded through the gate valve.

Further, below the susceptor between the electrostatic chuck 12 and the cooling jacket 9, there is provided a temperature adjusting heater 32 housed in a heater fixing base 31, and the temperature adjusting heater 32 is supplied from a power source 33. By adjusting the supplied power, the conduction of cold heat from the cooling jacket 9 can be controlled to adjust the temperature of the surface to be processed of the semiconductor wafer W.

Next, the configuration of the control system of the processing apparatus configured as described above will be described. A transmissive window 34 made of a transparent material such as quartz glass is attached to one side wall of the processing container 2 and sends light in the processing chamber to an optical sensor 36 via an optical system 35 so that the light is transmitted from the processing chamber. It is arranged to be able to send a signal to the controller 37 concerning the emission spectrum to be generated. Further, the processing container 2 has a pressure sensor 38 for detecting the pressure in the processing chamber.
Is attached to the controller 37 and is configured to be able to send a signal regarding the pressure in the processing chamber to the controller 37.
The controller 37 sends a control signal to the plasma generation high-frequency power source 7, the bias high-frequency power source 15, the refrigerant source 10, the temperature control power source 33, and the back-up voltage based on the feedback signals from these sensors or preset setting values. Cooling gas source 15 and processing gas mass flow controller 2
It is possible to optimally adjust the operating environment of the plasma processing apparatus by sending it to the No. 8 or the like.

Next, an embodiment in which the control method of the plasma etching apparatus constructed according to the present invention is applied to the above control system will be described.

First, according to the first aspect of the present invention, the emission spectrum of each wavelength detected from the processing chamber through the transmission window 34 when plasma is generated is processed by the optical system 35 including a spectroscope, and the optical sensor is processed. Due to 36, the amount existing in the processing chamber during the etching process changes relatively greatly.
Gas components, for example, react with the etching target such as an oxide film at the time of etching, and consumption in the processing chamber progresses, so the detected emission intensity remains at a low level. A signal representative of an emission spectrum for a process gas active species, for example a CF-based process gas such as CF or CF ₂ , which increases and thus increases the detected emission intensity; and
On the contrary, during etching, it is actively generated by reacting with an etching target such as an oxide film, and thus the detected emission intensity increases, but when etching is completed, it is not generated and thus the detected emission intensity decreases. Reaction gas, such as CO gas, and a second gas component whose amount present in the processing chamber does not fluctuate relatively even during etching, such as argon and nitrogen mixed for plasma stabilization. A signal representing an emission spectrum regarding the inert gas is observed, and a signal regarding these emission spectra is sent to the controller 37. Controller 37
In, the emission intensity ratio regarding the emission spectra of these two kinds of gas components is obtained.

When obtaining the emission spectrum, it is possible to detect the peak wavelength of the gas component to be observed through an appropriate interference filter and perform arithmetic processing, or the S / N ratio of the emission spectrum is calculated. If it is low, take the sum average of the emission spectra in a certain wavelength range,
It is also possible to reduce the influence of noise and obtain a highly accurate measurement value by performing arithmetic processing based on the total sum average value.

Since the emission intensity ratio obtained from the emission spectrum thus observed reflects the plasma state in the processing chamber in real time, the high frequency energy applied to the high frequency antenna according to the variation of the emission intensity ratio. It is possible to maintain the plasma state in the processing chamber optimally and to precisely control the etching end point in particular by performing feedback control. As a method of controlling the high frequency energy, as will be described later, a method of increasing or decreasing the high frequency power itself, a method of adjusting the frequency, phase, or amplitude of the high frequency energy via a matching box or the like can be adopted. is there.

According to the second aspect of the present invention, as a result of observing the correlation between the gas pressure in the processing chamber and the etching rate, as shown in FIG. 2, the etching rate is when the gas pressure is within a predetermined range. Since it is stable at a very high value, the pressure range (a ₁ to a ₂ ) when the etching rate falls within a predetermined range (for example, a range rather than b range or c range) is obtained in advance by etching treatment using a dummy wafer. In actual processing, the pressure fluctuation in the processing chamber is observed by the pressure sensor 38, and the pressure signal sent from the pressure sensor 38 to the controller 37 is controlled by the controller 37 so that it is a ₁ or a _2. By sending a control signal to each device and carrying out the etching process, stable etching can be carried out at a high etching rate.

Next, the structure of the plasma etching apparatus in the manufacturing process will be described with reference to FIG.
The same components as those of the plasma etching apparatus described above are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in the figure, on one side wall of the processing container 2 of the high frequency induction plasma processing apparatus 1 to which the present invention can be applied, a load lock chamber 40 adjacent to the processing container 2 via a gate valve 39 which can be opened and closed is provided. It is connected. The load lock chamber 40 is provided with a transfer device 41, for example, a transfer arm provided with an anti-static measure by coating an aluminum arm with conductive Teflon. Further, an exhaust pipe 42 is connected to the load lock chamber 40 from an exhaust port provided on the bottom surface, and a vacuum pump 44 can evacuate through a vacuum exhaust valve 43.

An adjoining cassette chamber 46 is connected to the side wall of the load lock chamber 40 via a gate valve 45 which is provided so as to be openable and closable. The cassette chamber 46 is provided with a mounting table 48 on which the cassette 47 is mounted. The cassette 47 is configured so that, for example, 25 semiconductor wafers W to be processed can be stored as one lot. Has been done. Also, the cassette chamber 46
Is connected to an exhaust pipe 49 from an exhaust port provided on the bottom surface, and the inside of the chamber can be evacuated by a vacuum pump 44 via a vacuum exhaust valve 50. Further, the other side wall of the cassette chamber 46 is configured to come into contact with the atmosphere through a gate valve 51 which is openably and closably provided.

Next, the operation of the plasma processing apparatus 1 configured as described above will be briefly described. First, the gate valve 51 provided between the atmosphere and the atmosphere is opened, and the cassette 47 accommodating the object to be processed W is mounted on the mounting table 48 of the cassette chamber 46 by the transfer robot (not shown). The valve 51 closes. The vacuum exhaust valve 50 connected to the cassette chamber 46 opens, and the vacuum pump 44
The cassette chamber 46 in a vacuum atmosphere, for example, 10
Exhausted to ^-1 Torr.

Then, the gate valve 45 between the load lock chamber 40 and the cassette chamber 46 is opened, and the transfer arm 4 is opened.
1, the object W is taken out of the cassette 47 placed in the cassette chamber 46, held and conveyed to the load lock chamber 40, and the gate valve 45 is closed. Vacuum exhaust valve 4 connected to the load lock chamber 40
3, the load lock chamber 40 is evacuated to a vacuum atmosphere, for example, 10 ⁻³ Torr by the vacuum pump 44.

Next, the load lock chamber 40 and the processing container 2
And the gate valve 39 between the transfer arm 41 and the transfer arm 41 transfers the object W to the processing container 2 and transfers it to a pusher pin (not shown) on the susceptor 4c. After returning to the chamber 40, the gate valve 39 is closed. After that, when a high-voltage DC voltage is applied to the electrostatic chuck 12 and the pusher pin is lowered to place the object W on the electrostatic chuck 12, the semiconductor wafer W is placed and fixed on the susceptor 4c. In the meantime, the inside of the processing container 2 is opened in the vacuum exhaust valve 52 so that a vacuum atmosphere, for example, 1
Exhausted to 0 ^-5 Torr.

Further, cold heat is supplied from the cooling jacket 9 to cool the processed surface of the semiconductor wafer W to a desired temperature. Then, a processing gas such as HF ₃ is introduced into the processing container 2 through the gas supply means 20, and an optimum pressure atmosphere is used to obtain an optimum etching rate which is obtained in advance using a dummy wafer according to the present invention. After being detected by the pressure sensor 38, the high-frequency power source 7 causes a high-frequency antenna to pass through the matching circuit 8 to reach, for example, 1
A high-frequency power of 3.56 MHz is applied to excite plasma in the processing container 2, and a back cooling gas for heat transfer is supplied to the back surface of the semiconductor wafer W and each bonding portion of the mounting table 4, and further mounted. By applying a bias potential to the table 4, the object W to be processed is subjected to plasma processing such as etching. During this period, the temperature of the inner wall of the processing chamber is set to 50 ° C to 100 ° C, preferably 60 ° C.
It is possible to prevent the reaction product from adhering to the inner wall by heating to 80 ° C to 80 ° C.

Further, according to the present invention, the emission spectrum generated from the inside of the processing container 2 at the time of etching is detected by the optical sensor 36 through the transmission window 34. Based on the present invention, the abundance amount by plasma reaction is large. A high frequency wave applied to the high frequency antenna so that the emission intensity ratio of the first gas component that changes relatively largely and the second gas component whose amount of which does not change relatively due to plasma reaction has an optimum value. The frequency, phase, amplitude, etc. of energy are appropriately controlled. When the detected emission intensity ratio reaches a predetermined value, it is determined that the etching is completed, the application of the high frequency energy is stopped, the supply of the processing gas is stopped, and the plasma processing operation is completed.

Next, in order to replace the processing gas and reaction products in the processing container 2, an inert gas such as nitrogen is introduced into the processing container 2 and the vacuum pump 44 evacuates. After the residual processing gas and reaction products in the processing container 2 are sufficiently exhausted, the processing container 2
The gate valve 39 provided on the side surface of the container is opened, the transfer arm 41 is moved from the adjacent load lock chamber 40 to the position of the object W in the processing container 2, and the object is lifted from the mounting table 4 by the pusher pin. The processing object W is received, conveyed to the load lock chamber 40, and the gate valve 39 is closed. In this load lock chamber 40,
If necessary, the object W to be processed is heated by a heater to room temperature, for example, 1
The temperature is raised to 8 ° C., and then the load lock chamber 40 is carried out to the atmosphere via the cassette chamber 46, thereby completing a series of operations.

In the embodiment shown in FIG. 1, the inner end 6a and the outer end 6b of the spiral coil are arranged as shown in FIG.
The high frequency power supply 7 and the matching circuit 8 are connected between the two, but the present invention is not limited to such a configuration. For example, as shown in FIG. 5, it is possible to adopt a configuration in which the high frequency power supply 7 and the matching circuit 8 are connected only to the outer end 6b of the spiral coil. With such a configuration, it is possible to generate good high frequency induction plasma in the processing container 2 even in a lower pressure atmosphere.

Next, with reference to FIGS. 6 to 15, embodiments relating to various apparatus configurations for optimally controlling the state of plasma excited through the high frequency antenna 6 in the processing container 2 will be described. In each drawing attached to this specification, the same reference numerals are given to the components having the same function, and the detailed description will be omitted.

FIG. 6 shows another embodiment of the high frequency antenna 6 attached to the outer wall surface of the insulating material 5. In this embodiment, a part 6c of the high frequency antenna 6 composed of a spiral coil is double-wound, and an overlapping part 6b thereof is formed.
And 6c to form a stronger electromagnetic field. By partially varying the number of turns of the spiral coil in this way, the density distribution of the plasma excited in the processing container 2 can be adjusted.
In the illustrated example, the overlapping portion of the high frequency antenna 6 is set to the outer peripheral portion, but the overlapping portion can be set to an arbitrary portion of the high frequency antenna 6 according to the required density distribution of plasma. In the illustrated example, the high frequency antenna 6
Although the overlapping portion is simply double-wound, the number of turns can be set to an arbitrary number depending on the required plasma density distribution.

In FIG. 7, the mounting table 4 is provided inside the processing container 2.
An example is shown in which second electrodes 53a and 53b made of aluminum, for example, are radially arranged at equal intervals so as to surround the. These electrodes 53a and 53b are supplied with high-frequency power supplies 55a and 55a through matching circuits 54a and 54b, respectively.
55b is connected. With this configuration, the mounting table 4
In addition to the bias high-frequency energy applied to the second electrode 53a, the high-frequency bias energy can be applied to the second electrodes 53a and 53b that surround the surface of the object W to be processed radially from the outer circumference in the radial direction at the same intervals. Therefore, it is possible to optimally control the state of plasma excited in the processing container 2 by adjusting the magnitude, amplitude, phase, frequency, etc. of each high-frequency energy.

FIG. 8 shows an embodiment in which a mesh-shaped electrode 56 made of, for example, silicon or aluminum is arranged inside the processing container 2 below the gas blowing surface of the gas supply means 20 and above the mounting table 4. It is shown. A variable power source 57 is connected to the electrode 56, and an appropriate current is caused to flow through the electrode 56 to control the distribution of the electric field formed by the action of the high frequency antenna 6 in the processing container 2 and It is possible to excite plasma having a desired density distribution inside.

Further, in the embodiment shown in FIG. 1, the high frequency antenna 6 is arranged on the upper surface of the processing container 2 via the insulating material 5 such as quartz glass, but the present invention is not limited to such embodiment. For example, as shown in FIG. 9, a part of the side wall of the processing container 2 is covered with an insulating material 5 such as quartz glass or ceramics.
It is also possible to adopt a configuration in which the second high frequency antenna 59 is attached to the outer wall surface of the insulating material 58. These second high frequency antennas 59 are preferably arranged in a coil shape, and are configured so that high frequency energy can be applied from a high frequency power supply 61 connected through a matching circuit 60. With this configuration, plasma can be excited also from the side wall portion of the processing container 2. Therefore, by adjusting the high frequency energy applied to each antenna, a high-density and uniform plasma can be processed in a desired density distribution. 2 can be generated, and more precise plasma processing can be performed.

Further, as shown in FIG. 10, a part of the mounting table 4 is composed of an insulating material 62 such as quartz glass, a high frequency antenna 63 is arranged on the lower surface thereof, and a high frequency power source 68 connected through a matching circuit 67. It is also possible to adopt a configuration in which more high frequency energy is applied to the high frequency antenna 63.
With such a configuration, it is possible to excite plasma from the lower surface of the mounting table 4 of the processing container 2. Therefore, by adjusting the high frequency energy applied to each antenna, high density and uniform plasma can be obtained with a desired density distribution. With this, it is possible to generate in the processing container 2, and it is possible to perform more precise plasma processing.

Further, as shown in FIG. 11, a focus ring arranged around the upper surface of the mounting table 4 is made of an insulating material 69 such as quartz glass or ceramics, and a high frequency antenna 70 is arranged around it, and the high frequency antenna 70 is provided. It is also possible to apply a high-frequency energy from a high-frequency power source 72 connected via a matching circuit 71.
With such a configuration, it is possible to excite the plasma from around the mounting table 4 of the processing container 2. Therefore, by adjusting the high frequency energy applied to each antenna, a high density and uniform plasma can be obtained with a desired density distribution. With this, it is possible to generate in the processing container 2, and it is possible to perform more precise plasma processing.

When plasma-treating a relatively large area to be processed such as an LCD, a plurality of high frequency antennas 74a, 74b, 74c and 75d are arranged on the upper surface of the processing container 2 as shown in FIG. Attached to the outer wall of the insulating material 5, each high frequency antenna has a matching circuit 75
It is also possible to employ a configuration in which high-frequency energy is applied from high-frequency power sources 76a, 76b, 76c, 76d connected via a, 75b, 75c, 75d. With such a configuration, it becomes possible to excite high-density and uniform high-frequency plasma even in a large-sized processing container 2 that processes an object to be processed having a relatively large area.

In the above embodiment, the object W to be processed is mounted on the upper surface of the mounting table 4 and the high frequency antenna 6 arranged on the upper surface of the processing container 2 excites plasma. However, the present invention is not limited to such a configuration.
For example, it is possible to adopt a face-down method as shown in FIG. In this device configuration, each component of the processing device shown in FIG. 1 is arranged upside down, and components having the same function as each component shown in FIG. 1 are designated by the same reference numerals. At the same time, in order to distinguish from the constituent elements of FIG. 1, “′” is attached. However, in the case of the face-down type apparatus shown in FIG. 13, the vertically movable support mechanism 76 for supporting the object W to be processed from below and the object W to be processed are electrostatic chucks 12.
It is preferable to provide a vertically movable pusher pin mechanism 77 for further removal. By adopting such a configuration, the processing surface of the object W to be processed can be protected from contamination such as fine particles, so that the yield and the throughput can be further improved.

Alternatively, as shown in FIG. 14, a substantially cylindrical processing container 2 "is arranged vertically, insulating materials 5" are arranged on both surfaces thereof, and the high frequency antenna 6 is provided on the outer wall surface of each insulating material 5 ". It is also possible to adopt a configuration in which the workpiece W is attached by suction to both surfaces of the mounting table 4 ″ which is arranged substantially vertically in the center of the processing container 2 ″ via the electrostatic chucks 12 ″. Note that each component of the apparatus shown in Fig. 14 is almost the same as each component of the processing apparatus shown in Fig. 1, and those having the same function as each component shown in Fig. 1 are the same. Figure 1 with reference numbers
In order to distinguish it from the constituent elements of "." By adopting such a configuration, it is possible to process a plurality of objects W to be processed at the same time, and since the surface to be processed of the object to be processed W is arranged vertically, the surface to be processed is protected from contamination such as fine particles. It is protected, and the yield and the throughput can be further improved.

FIG. 15 shows still another embodiment of the plasma processing apparatus according to the present invention. In this embodiment, the susceptor 4 is completely separated from the wall surface of the processing container 2, that is, is placed on the vertically movable lifting mechanism 78, and a pipe for supplying a cold heat source or a heat transfer gas to the susceptor 4. The road or various electric circuits are arranged inside the elevating mechanism 78. By adopting such a configuration, the surface to be processed of the susceptor 4 is moved up and down with respect to the high frequency antenna 6 which is the plasma generation source to adjust the surface to be moved to a space having an optimum plasma density distribution. It becomes possible to perform processing.

The preferred embodiment of the present invention has been described above by taking the plasma etching apparatus as an example, but the present invention is not limited to such an embodiment, and a plasma CVD apparatus, a plasma ashing apparatus, a plasma sputtering apparatus, etc. The present invention can also be applied to other plasma processing apparatuses, and the object to be processed is not limited to the semiconductor wafer and can be applied to the LCD substrate and other objects to be processed.

[0048]

As described above, according to the first aspect of the present invention, the amount existing in the processing chamber during the etching processing, which reflects the plasma state in the processing container in real time, changes relatively greatly. The emission intensity ratio between the first gas component and, conversely, the second gas component in which the amount present in the processing chamber does not fluctuate relatively even during the etching process, is observed. By feedback-controlling the high-frequency energy applied to the high-frequency antenna according to the fluctuation of, it is possible to maintain the plasma state in the processing chamber optimally with high accuracy, and particularly to precisely control the end time of etching. Therefore, highly accurate plasma etching can be performed.

According to the second aspect of the present invention, only by observing the gas pressure in the processing container and feedback-controlling the state of the plasma in the processing container according to the gas pressure, it is possible to achieve a stable high etching rate. Since the plasma processing of the processing object can be performed, the control system can be simplified.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a plasma processing apparatus to which a control method of a plasma etching processing apparatus configured according to the present invention can be applied.

FIG. 2 is a graph showing a relationship between an etching rate obtained from a dummy wafer and a gas pressure in a processing container.

3 is a configuration diagram of a manufacturing system incorporating the plasma processing apparatus shown in FIG.

4 is a plan view showing an embodiment of a high frequency antenna part applicable to the processing apparatus of FIG. 1. FIG.

5 is a plan view showing another embodiment of the high frequency antenna part applicable to the processing apparatus of FIG. 1. FIG.

FIG. 6 is a schematic cross-sectional view showing an embodiment of a processing apparatus to which a high-frequency antenna having still another structure is attached.

FIG. 7 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which a second electrode is attached inside a processing container.

FIG. 8 is a schematic cross-sectional view showing another embodiment of the processing apparatus in which the second electrode is installed in the processing container.

FIG. 9 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which a second high frequency antenna is attached to the side wall of the processing container.

FIG. 10 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which a second high-frequency antenna is attached inside the mounting table of the processing container.

FIG. 11 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which a second high frequency antenna is attached around a focus ring of a mounting table of a processing container.

FIG. 12 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which a plurality of high frequency antennas are arranged on the outer wall surface of the insulating material of the processing container.

FIG. 13 is a schematic cross-sectional view showing an embodiment of a face-down type processing apparatus.

FIG. 14 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which objects to be processed are vertically arranged.

FIG. 15 is a schematic cross-sectional view showing an embodiment of a processing apparatus in which a mounting table is configured separately from a processing container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plasma processing apparatus 2 Processing container 4 Mounting table 5 Insulating material 6 High frequency antenna 7 High frequency power supply 8 Matching circuit 20 Gas supply means 34 Transmission window 36 Optical sensor 37 Controller 38 Pressure sensor W Semiconductor wafer

Claims (2)

[Claims] 1. An induction plasma is excited in a processing chamber by applying a high-frequency power to a high-frequency antenna arranged outside the processing chamber via an insulator, and an object to be processed arranged in the processing chamber is excited. When controlling the plasma etching apparatus that performs the etching process, the first gas component in which the amount existing in the processing chamber during the etching process changes relatively greatly, and the amount existing in the processing chamber during the etching process does not change relatively. Second
The method for controlling a plasma etching processing apparatus, comprising: observing an emission intensity ratio with respect to the gas component and controlling the high frequency energy applied to the high frequency antenna according to the variation of the emission intensity ratio. 2. An induction plasma is excited in a processing chamber by applying high-frequency power to a high-frequency antenna arranged outside the processing chamber via an insulator, and a target object arranged in the processing chamber is excited. When controlling the plasma etching apparatus that performs the etching process, a dummy wafer placed in a predetermined etching atmosphere is subjected to the etching process, and the correlation between the pressure in the processing chamber and the etching rate at that time is obtained in advance. The pressure range in which the etching rate falls within a predetermined value range is determined in advance, and in the actual etching process, the pressure in the processing chamber is observed, and the pressure is controlled to be within the pressure range with respect to the object to be processed. A method of controlling a plasma etching processing apparatus, which comprises performing etching processing by means of a plasma etching method.