JP3204544B2 - Processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, as a method for controlling a pressure in a processing chamber for plasma processing a semiconductor wafer as an object to be processed to a set value, for example, a method disclosed in JP-A-63-58833 is known. . In this method, a pressure value in the processing chamber is monitored, an on-off valve provided between an exhaust pipe for exhausting the processing chamber and an exhaust unit is controlled by a pressure control device, and the pressure in the processing chamber is adjusted to a desired pressure value. Was to be.

[0003]

However, in an apparatus for performing plasma processing on an object to be processed, for example, a semiconductor wafer by applying an AC voltage, for example, a high-frequency voltage, in the above-mentioned processing chamber, the plasma is generated. Electromagnetic noise such as the high frequency and harmonics of the high frequency is output from the pressure detecting means to a pressure detecting means (for example, a diaphragm vacuum gauge, a Pirani vacuum gauge, etc.) for detecting a pressure value in the processing chamber where the plasma is generated. It has been found that it is difficult to obtain a stable pressure signal by superimposing the pressure signal. Further, there is a problem that a pressure control device for controlling the pressure in the processing chamber to a desired pressure value based on the pressure signal monitors the above-mentioned electromagnetic wave noise and slightly fluctuates the pressure in the processing chamber. . Further, since the pressure in the processing chamber fluctuates slightly, the object to be processed in the processing chamber cannot be uniformly processed,
There is an improvement that the yield and productivity of the object to be processed are reduced.

An object of the present invention is to provide a processing apparatus capable of suppressing electromagnetic noise superimposed on a pressure signal output from a pressure detecting means for detecting a pressure in a processing chamber.

[0005]

According to the present invention, there is provided a process for applying a high-frequency power to an electrode provided in a container made of a conductive material to generate plasma in a space in the container and to process the object. In the apparatus, a pressure detector provided in a space communicating with the space in the container, and a porous member formed of a conductive member provided between the plasma generation site and the pressure detector in the communicating space. And a net-like electromagnetic wave shielding member, wherein a positive potential higher than the potential of the plasma is applied to the electromagnetic wave shielding member.

[0006]

According to the present invention, in a space provided with a pressure detector communicating with a space in a container, a porous or net-like electromagnetic shield made of a conductive member is provided between a plasma generation site and the pressure detector. Since the member is arranged and a positive potential higher than the potential of the plasma in the container is applied to the electromagnetic wave shielding member, the electromagnetic wave noise can be absorbed by the electromagnetic wave shielding member, and the pressure in the processing chamber is reduced. Electromagnetic noise superimposed on the pressure signal output from the pressure detecting means to be detected can be suppressed, and wear of the electromagnetic shield member by plasma can be prevented,
It is also possible to block electromagnetic waves.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a magnetron discharge type dry etching apparatus will be described below in detail with reference to the drawings. As shown in FIGS. 1, 2 and 3, the magnetron discharge type dry etching apparatus 1 is formed in a substantially cylindrical shape in which an object to be processed, for example, a semiconductor wafer 2 is vertically closed with a metal such as aluminum for processing by plasma. The processing chamber 3 is provided. A first opening 4 for carrying the semiconductor wafer 2 into and out of the processing chamber 3 is provided on a side wall of the processing chamber 3, and a first gate valve 5 for opening and closing the opening 4 is provided. Have been. A load lock chamber 50 is provided beside the processing chamber 3, and the load lock chamber 50 is provided with the semiconductor wafer 2.
A transfer mechanism 51 for carrying in or out the processing chamber 3 is provided. A second opening 4a for loading or unloading the semiconductor wafer 2 into or from the load lock chamber 50 is provided at the other end of the side wall of the load lock chamber 50, and opens and closes the opening 4a. A second gate valve 5a is provided. In addition, a supply / exhaust pipe (not shown) for reducing the pressure in the load lock chamber 50 to the atmosphere or reduced pressure is provided.

Further, a processing gas (for example, CHF3, CF4, CCL4, etc.) is provided at another portion of the side wall of the processing chamber 3.
Gas supply pipe 6 connected to supply gas into the processing chamber 3
Is provided. Further, an exhaust port 7 for exhausting the inside of the processing chamber 3 is opened in the bottom wall of the processing chamber 3, and the exhaust port 7 is controlled by a pressure control device 8 provided so as to change the exhaust capacity. An opening / closing valve, for example, a butterfly valve 9 is provided, and an exhaust means, for example, a vacuum pump 10 is connected to the butterfly valve 9.

A pair of electrodes are provided on the upper and lower portions of the processing chamber 3, and one upper electrode 11 is fixedly suspended above the processing chamber 3 by a holder 12 made of an insulating material. Connected to earth. The semiconductor wafer 2 is placed on the other lower electrode 13, and a frequency of, for example, 13.56 MHz or 40 MHz is applied to the bottom wall of the processing chamber 3 through a power supply rod 15 inserted through an insulator 14. A high-frequency power supply 16 for outputting high-frequency power is connected, and a parallel plate electrode of a cathode coupling (RIE) type is configured.

A permanent magnet 20 for forming a magnetic field parallel to the surface of the semiconductor wafer 2 is provided above the processing chamber 3, and a rotating shaft 2 is provided above the permanent magnet 20.
The rotary shaft 21 is rotatably supported by being penetrated by a magnetic shield member provided to prevent magnetic leakage, for example, a cover 22 made of permalloy. It is configured to be rotationally driven by a motor 23 as a rotating means provided outside the cover 22.

Further, as shown in FIG. 2, the side wall of the processing chamber 3, for measuring the pressure of the processing chamber 3, punished
An opening 30 which is a space communicating with the plasma generation space of the science room 3 is provided. The opening 30 is provided with a pressure detecting means 25 (for example, a conductive O-ring 32 through a conductive O-ring 32). , A diaphragm vacuum gauge, a Pirani vacuum gauge) are hermetically connected by screwing a bolt 35 to the processing chamber 3 via a spring washer 34 with a mounting bracket 33. The pressure detecting means 25 has a detection opening 25a as a detection port for detecting the pressure in the processing chamber 3. Further, the O-ring 32
On the inner periphery of the O-ring 32 so as to be in close contact with the O-ring 32,
A conductive member, for example, a metal-made support ring 31 such as stainless steel is mounted around the support ring 31, and a conductive member, for example, a nichrome wire (Ni- Cr ) or an aluminum wire ( Al) or Kanthal (trade name) which is an alloy wire of iron (Fe), chromium (Cr), and aluminum (Al) or the like ( mesh)
The electromagnetic wave shield 36 formed in the shape of FIG. The electromagnetic wave shield 36 generates plasma from the processing chamber 3.
In the opening 30 which is a space communicating with the raw space,
Is provided between the site of occurrence of the suma and the pressure detecting means 25
I have. Further, the electromagnetic wave shield 36 is electrically connected to the pressure detecting means 25 via the O-ring, and the electromagnetic wave shield 36 is configured to be grounded at a ground point 25b.

The pressure signal output from the pressure detecting means 25 is connected to an apparatus controller 40 provided to manage and control the pressure in the processing chamber 3. It is also connected to the pressure control device 8 for controlling the internal pressure. A pressure instruction signal for instructing the pressure in the processing chamber 3 is connected to the pressure control device 8 from the apparatus controller 40, and a pressure display signal for displaying the pressure in the processing chamber 3 is connected to the display 41. I have. As described above, the magnetron discharge dry etching apparatus 1 is configured.

Next, a processing operation for processing an object to be processed will be described. From the state shown in FIG. 1, the gate valve 5a is opened, and the semiconductor wafer 2 is loaded into the load lock chamber 50 from the unprocessed wafer cassette (not shown) provided outside the load lock chamber 50 by the transfer mechanism 51, and the gate is opened. Valve 5
is closed, and the pressure inside the load lock chamber 50 is reduced to a predetermined pressure, for example, 1 × 10 −3 Torr by an exhaust pipe (not shown). Next, the gate valve 5 is opened, and the semiconductor wafer 2 is loaded into the processing chamber 3 by the transfer mechanism 51 and placed on the lower electrode 13.
Move outside and close gate valve 5. Next, processing chamber 3
The internal pressure is set to a predetermined degree of vacuum, for example, 1 × 10 −4 Torr.
In order to reduce the pressure, the device controller 40 transmits an instruction signal for fully opening the butterfly valve 9 to the pressure control device 8, and the pressure control device 8 fully opens the butterfly valve 9 according to this instruction. Further, after the degree of vacuum is reached, the processing gas is supplied from the gas supply pipe 6 to, for example, 100 sccm.
At the same time, a signal for releasing the full-open state is transmitted from the device controller 40 to the pressure control device 8, and a pressure instruction signal is further transmitted.

Next, the pressure control device 8 outputs the pressure in the processing chamber 3 from the pressure detecting means 25 in order to set the pressure in the processing chamber 3 to a pressure value instructed by the pressure instruction signal from the device controller 40, for example, 40 mTorr. The butterfly valve 9 is opened and closed while monitoring the pressure signal, and is controlled so as to maintain the indicated pressure value. Further, a high-frequency power is applied to the lower electrode 13 from a high-frequency power supply 16 and the plasma 2 is supplied into the processing chamber 3.
4 is generated. Further, by driving the motor 23 and rotating the magnet 20 connected to the rotating shaft 21, a portion having a high plasma density also rotates in synchronism with the rotation, and the semiconductor wafer 2 is subjected to the indicated pressure by the rotated plasma. Etched under the value.

After this process is completed, the rotation of the motor 23 is stopped, the application of the high-frequency power is released, and the supply of the processing gas is stopped. Next, a predetermined gas, for example, nitrogen (N 2) is supplied into the processing chamber 3 from the gas supply pipe 6, and after the gas is once evacuated by the vacuum pump 10, the pressure becomes equal to the pressure in the load lock chamber 50. The pressure control device 8 drives the butterfly valve 9 to open and close while monitoring the pressure signal from the pressure detecting means 25 so that the pressure signal is monitored. next,
The gate valve 5 is opened, and the semiconductor wafer 2 placed on the lower electrode 13 by the transfer mechanism 51 is loaded into the load lock chamber 50.
And the gate valve 5 is closed. Further, a predetermined gas, for example, nitrogen (N2) is supplied into the load lock chamber 50 through an air supply pipe (not shown), and after the pressure is made equal to the atmospheric pressure, the gate valve 4a is opened and the semiconductor wafer 2 is loaded by the transfer mechanism 51. It is housed in a processed wafer cassette (not shown) provided outside the lock chamber 50. The above operations are sequentially repeated to process the semiconductor wafer.

As can be understood from the above description of the processing operation,
The pressure signal output from the pressure control means 25 plays an important role in processing. The pressure signal waveform during the processing of the object to be processed by the plasma described above is shown in FIG.
As shown in (1), the pressure signal output from the pressure detection means 25 (for example, a diaphragm vacuum gauge, a Pirani vacuum gauge, etc.) is a frequency of a high frequency bias applied from the high frequency power supply 16, for example, a pressure signal before 13.56 MHz is applied. The signal is superimposed on the signal 71 and becomes a superimposed pressure signal 70.

The superimposed pressure signal 70 has a high-frequency power applied from the high-frequency power supply 16 of, for example, 400 W, and the inside of the processing chamber 3 at, for example, 40 mTorr. Is equivalent to Further, the pressure in the processing chamber 3 is set to, for example, 20 mTo.
Even when the pressure is rr, a pressure amplitude width equivalent to the above amplitude width is obtained, and this fluctuation is proportional to the applied power of the high frequency power applied from the high frequency power supply 16. Further, the superimposed pressure signal 70 is transmitted to the pressure control device 8, and the pressure control device 8 slightly changes the opening / closing angle of the butterfly valve 9 as shown by an angle aging wave 73 in FIG.

When the processing gas, for example, CHF3 is supplied at a flow rate of, for example, 50 sccm under the above pressure, the maximum fluctuation width α of the opening / closing angle chronological wave 73 is 0 to 90 degrees in a range from the fully closed to the fully opened angle. Then, it fluctuates about 1 degree. This one degree change is about 6 mTo
rr. Further, as the opening / closing angle slightly fluctuates as shown by the angle aging wave 73, the pressure in the processing chamber 3 fluctuates slightly, and the etching characteristics of the semiconductor wafer 2 being processed, for example, the selectivity fluctuate with time. Processing cannot be performed uniformly.

Therefore, when the above-described electromagnetic wave shield 36 is provided between the processing chamber 3 and the pressure detecting means 25, the amplitude width 70b of the superimposed pressure signal 70 is about 1 mTorr under the above-mentioned conditions, as shown in FIG. The maximum fluctuation width β of the opening / closing angle chronological wave 73 also decreases to about 0.2 degrees. This 0.2 degree fluctuation is a fluctuation of about 1 mTorr in pressure, and it can be seen that the fluctuation of the pressure in the processing chamber 3 is suppressed.

According to the above embodiment, the following effects can be obtained. (1) By providing an electromagnetic wave shield in front of the detection port 25a of the pressure detection means 25 for detecting the pressure in the processing chamber 3, noise of electromagnetic wave noise superimposed on the pressure signal output from the pressure detection means 25 The amount can be reduced. (2) Since the noise amount of the electromagnetic wave noise can be reduced, the operation amount of the fluctuation operation that fluctuates due to the electromagnetic wave noise can be reduced by the pressure control device that controls the pressure in the processing chamber 3. (3) Since the fluctuation of the pressure in the processing chamber 3 is reduced, it is possible to suppress the variation of the selection ratio due to the etching of the object to be processed in the processing chamber 3, and to enhance the quality and reliability of the product. be able to. (4) Since the electromagnetic wave shield is bonded to the support ring, it can be inserted and removed, and can be easily replaced even during the life of the electromagnetic wave shield.

Next, the second embodiment will be described. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. As shown in FIG. 6, an opening 30 provided in a side wall of the processing chamber 3 for measuring a pressure in the processing chamber 3 is provided.
The outer peripheral end 61 of the electromagnetic shield 36 shown in FIG. 7 is welded to the processing chamber 3 so as to cover the entire opening 30. The electromagnetic wave shield 36 is grounded via the ground point 3a of the processing chamber 3. As described above, the influence of the electromagnetic wave noise can be further reduced by providing the double electromagnetic wave shield.

Next, a description will be given of a third embodiment. The same parts as those of the first embodiment are denoted by the same reference numerals, and the description is omitted. As shown in FIG. 8, the inner peripheral end 6 of the detection opening 25a of the pressure detecting means 25 for detecting the pressure in the processing chamber 3 is provided.
6 is provided with an electromagnetic wave shield 36 by welding an outer peripheral end of the electromagnetic wave shield 36. Further, the electromagnetic wave shield 36 is configured to be grounded via a ground point 25b of the pressure detecting unit 25. With the above configuration, the grounding of the electromagnetic wave shield is further ensured, and the shielding effect can be further enhanced.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. Opening 3 for measuring pressure in processing chamber 3
It goes without saying that the electromagnetic wave shield may be provided anywhere between 0 and the pressure detection means 25, and that the electromagnetic wave shield 36 may be provided anywhere before the detection port 33 of the pressure detection means 25. Needless to do. Further, a conductive material having a high resistivity is used for a member forming the electromagnetic wave shield 36, and a DC radio wave is applied to the electromagnetic wave shield 36, so that the electromagnetic wave shield 36 is used as a heating element, and the electromagnetic wave shielding effect and the electromagnetic wave shielding effect are improved. It is also possible to combine the removal of the generated compound attached to the electromagnetic wave shield 36. Further, in the plasma etching apparatus, a positive electric potential higher than the electric potential of the generated plasma is applied to the electromagnetic wave shield 36 while the electromagnetic wave shield 36 is being processed, thereby forming the electromagnetic wave shield 36 by plasma. To prevent wear of components
It is also possible to block electromagnetic waves. In the above embodiment, the description has been given of the magnetron discharge type dry etching apparatus. However, it is obvious that the present invention can be applied to a processing apparatus such as a plasma CVD apparatus, an LCD plasma apparatus, and an ECR plasma apparatus. Further, the processing apparatus is not limited to a semiconductor manufacturing apparatus, and may be any processing apparatus that is a processing chamber that performs processing of an object to be processed by applying an AC voltage and that includes a pressure detection unit that detects a pressure value in the processing chamber. Also applicable to

[0024]

As described above, according to the present invention,
In a space provided with a pressure detector that communicates with the space inside the container
Between the plasma generation site and the pressure detector
Or net-like electromagnetic shielding member made of conductive material
The electromagnetic wave shielding member
Noise can be absorbed, and a positive potential higher than the potential of the plasma in the container is applied to the electromagnetic wave shielding member, thereby preventing the electromagnetic wave shielding member from being worn by the plasma and further blocking the electromagnetic waves. It is also possible.

[0025]

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing a magnetron discharge type dry etching apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a mounting portion of the electromagnetic wave shield according to the first embodiment.

FIG. 3 is a perspective view showing the mounting of the electromagnetic wave shield of the first embodiment.

FIG. 4 is a characteristic diagram for explaining the operation of the first embodiment.

FIG. 5 is a characteristic diagram for explaining the operation of the first embodiment.

FIG. 6 is a schematic sectional view of a mounting portion of an electromagnetic wave shield according to a second embodiment.

FIG. 7 is a perspective view illustrating the mounting of the electromagnetic wave shield of the second embodiment.

FIG. 8 is a perspective view showing the mounting of the electromagnetic wave shield of the third embodiment.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Magnetron discharge dry etching apparatus 2 Object to be processed (semiconductor wafer) 3 Processing chamber 8 Pressure control device 9 Opening / closing valve (butterfly valve) 10 Exhaust means (vacuum pump) 16 AC voltage (high frequency power supply) 25 Pressure detecting means 25a Detecting port DESCRIPTION OF SYMBOLS 31 Support ring 32 Conductive O-ring 36 Electromagnetic wave shield 40 Device controller

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/3065 C23C 16/509

Claims (1)

(57) [Claims] 1. A processing apparatus for applying a high-frequency power to an electrode provided in a container made of a conductive material to generate plasma in a space in the container to process an object to be processed. A pressure detector provided in a space that communicates with a porous or net-like electromagnetic wave shielding member made of a conductive member provided between the plasma generation site and the pressure detector in the communication space. And a positive potential higher than a potential of the plasma is applied to the electromagnetic wave shielding member.