JPH0594955A - Plasma processing device - Google Patents

Abstract

PURPOSE:To provide a plasma processing device where microwave discharge plasma is always uniform in plane density distribution on a substrate, where the device concerned is made to function to introduce microwaves generated from a microwave generator into a vacuum chamber through the inside of a microwave transmission line provided with an EH tuner as a component element to generate microwave discharge plasma inside a vacuum chamber to treat the surface of a treatment substrate inside the vacuum chamber. CONSTITUTION:An emission intensity meters are mounted on the wall of a vacuum chamber at several positions or a probe is mounted on a substrate transfer hand 12 to make the hand move, or Faraday cups 16 are mounted on the substrate transfer hand 12, the plane density distribution of microwave discharge plasma is automatically measured basing on the signals emitted from the positions of the Faraday cups in the substrate radial direction, an EH tuner 10 and a microwave generator 11 are automatically controlled so as to make the microwave discharge plasma uniform in plane density distribution, and then the vacuum chamber 1 is made to serve as a device which enables a processing object substrate to be subjected to a processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for utilizing plasma formed by using microwaves for forming a thin film on a substrate to be processed or processing such as etching. A vacuum container in which a microwave inlet that is hermetically closed by a plate-shaped microwave transmission window is formed, a microwave generator, and a hollow conductor that couples the vacuum container and the microwave generator to transmit microwaves inside. And an EH tuner that forms a part of the microwave transmission path and adjusts the in-piece dance of the transmission path, and transmits the microwave oscillated by the microwave generator through the microwave transmission path to a microwave transmission window. The present invention relates to a plasma processing apparatus which is introduced into a vacuum container after passing through it to generate microwave discharge plasma in the vacuum container to perform surface treatment of a substrate to be processed in the vacuum container.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, in a film forming or etching process, a microwave plasma processing apparatus capable of generating and maintaining stable plasma even at a low pressure has come to be used due to a fine structure of a semiconductor device. There is. Most of them are EIectron CycIotrn Resona
nce, hereinafter referred to as ECR) phenomenon, which is an ECR type plasma processing apparatus for generating high density and highly active plasma.

An example of the configuration of this type of plasma processing apparatus is shown in FIG.
Shown in. The apparatus comprises a vacuum container 1 formed as a stepped cylinder, a plate-shaped microwave transmission window 4 that hermetically closes a circular microwave introduction port formed at the center of the upper end surface of the cylinder, and an internal atmosphere. The microwave transmission parts 7, 8 and 9 which are hollow conductors through which the microwaves oscillated by the microwave generator pass, and the impedance of the microwave transmission path from the microwave generator 11 to the vacuum container 1 arranged in the middle. The main components are an EH tuner 10 for adjusting the temperature, a solenoid 6 coaxially surrounding the vacuum container 1, and a substrate transfer hand 12 for loading and unloading the substrate 2 from outside the vacuum container 1.

As shown in FIGS. 7 and 8, the EH tuner 10 is provided with two branches 10b and 10c in a main waveguide 10a having the same cross section as that of the microwave transmission section 9, and the two branches 10b and 10c are respectively reached. A square piston-shaped plunger 10d that completely reflects waves on its bottom surface is incorporated. By moving the piston-like blanker 10d forward or backward in the branches 10b and 10c, reflected waves of arbitrary amplitude and phase are created, and the impedance of the transmission line is adjusted equivalently. In addition, in the microwave transmission part 7, the cross-sectional shape of the internal space is changed from the square of the connection part with the transmission part 8 to the substrate 2 of the connection part with the vacuum container 1.
It is a frustum shape that gradually changes toward a circle with a larger diameter, and the microwave traveling through the transmission line has a wave front wider than the substrate area without changing the electric field direction. Introduced into 1.

The solenoid 6 is arranged such that its geometric center is located on the atmospheric side of the microwave transmitting window 4, and the electric current flowing through the solenoid 6 is adjusted to set the ECR condition on the vacuum side of the microwave transmitting window 4. When the magnetic field region to be filled is formed, the microwave oscillated by the microwave generator 11 is introduced into the vacuum container 1 through the microwave transmission window 4, and the film forming raw material gas is introduced from the gas introduction system 5. , The gas is efficiently ionized in the ECR magnetic field region and turned into plasma, and this plasma is directed to the substrate stand 3 direction along the magnetic force lines of the divergent magnetic field formed by the solenoid 6, and a thin film is formed on the surface of the substrate 2. At this time, conventionally, in order to efficiently introduce the microwave oscillated by the microwave generator 11, the EH tuner 10 is adjusted to set the reflected wave to the minimum.

[0006]

In the plasma processing apparatus described above, the density distribution of the generated plasma in the surface of the substrate 2 may be extremely uneven. An example of each measurement result of the film thickness distribution and the plasma density distribution on the formed substrate at this time is shown in FIGS. 4 and 5. In the figure, the zero point on the horizontal axis means the center position of the microwave introduction port, and the measurement position shows the radial distance from the center of the microwave introduction port.
Comparing the two measurement results, it can be seen that the plasma density distribution affects the film thickness distribution. Note that these distributions have a slight difference in the circumferential direction in the plane parallel to the substrate. Therefore, even if the microwave transmission part 7 has a rectangular cross-sectional shape over the entire length like the microwave transmission part 9, it is considered that the microwave transmission part 7 can be obtained from the same distribution as in FIGS. 4 and 5. Such film thickness nonuniformity is a major problem in film formation in the semiconductor manufacturing process, and the mechanism of the plasma density nonuniformity phenomenon has not been clarified even now, and it has been a major problem as an apparatus.

An object of the present invention is to form a plasma having a uniform in-plane density distribution in a vacuum container,
Thus, it is possible to obtain a plasma processing apparatus in which the processing speed distribution on the substrate surface, and thus the film thickness distribution is uniform when the processing is film formation.

[0008]

In order to solve the above-mentioned problems, in the present invention, a microwave introduction port which is formed in a cylindrical shape and is hermetically closed by a plate-shaped microwave transmission window is formed on one end face. A vacuum container, a microwave generator, a vacuum container and a microwave generator, and a part of a microwave transmission line formed of a hollow conductor through which microwaves are transmitted to adjust the impedance of the transmission line. And an EH tuner for transmitting microwaves oscillated by a microwave generator through a microwave transmission path and through a microwave transmission window to be introduced into a vacuum container to generate microwave discharge plasma in the vacuum container. In a plasma processing apparatus for performing a surface treatment on a substrate to be processed in the vacuum container, a plasma density distribution of the microwave discharge plasma on the substrate to be processed on the surface , Automatically measured by a luminescence intensity meter attached to a plurality of positions of the vacuum container wall, or automatically measured while moving the substrate transfer hand by the probe attached to the substrate transfer hand in the diameter direction of the substrate to be processed, or EH is automatically measured from the measured plasma density distribution using a Faraday cup attached to the substrate transfer hand.
The tuner and the microwave generator are controlled to control the non-uniformity of the plasma density distribution to be a predetermined value or less, and then the apparatus for entering the surface treatment step of the substrate to be treated is provided. If the plasma density distribution is performed using a Faraday cup, it is preferable to use a plurality of Faraday cups.

[0009]

The present invention has been made based on the investigation by the present inventor that the above-mentioned extremely non-uniform phenomenon of the plasma density distribution can be solved by increasing and decreasing the reflected wave by adjusting the EH tuner and the microwave generator. It is a thing. Therefore,
Signals from luminescence intensity meters installed at multiple positions on the wall of the vacuum vessel so that the direction of light emitted from the probe is perpendicular to the diameter of the substrate, or signals from various positions in the substrate diameter direction of the probe attached to the substrate transfer hand. Alternatively, the in-plane plasma density distribution on the substrate to be processed is measured from the signal from the Faraday cup at each position on the substrate diameter, and a movable plunger with a built-in EH tuner is used so that the nonuniformity of this distribution is below a predetermined value. While moving, by controlling the amplitude and phase of the reflected wave due to this movement, by controlling the output adjustment mechanism of the microwave generator so that the microwave power constantly injected into the vacuum container becomes constant, The processing can be performed in the state where a uniform plasma density distribution is secured from the beginning of the processing step of the substrate to be processed without lowering the processing speed. When a Faraday cup is used to measure the plasma density distribution, multiple Faraday cups are placed on the substrate transfer hand so that the ion current in the plasma can be measured over the entire range of the substrate diameter. The plasma density distribution can be measured easily and in a short time without requiring a control mechanism for stopping and re-moving at each position.

[0010]

1 shows a first embodiment of the present invention. In the figure, the probe 14 attached to the substrate transfer hand 12 applies a voltage between the two probes 12 a protruding at the tip, and moves the probe 12 a in the diameter direction of the substrate 2 while flowing a current through the probe 12 a. To measure. This current is always sent as a measurement signal to the control device 15, and the measurement signal value sent here is analyzed to determine the uniformity of the plasma density distribution. If the uniformity is insufficient, the control signal is sent. It is output to the EH tuner 10 and the microwave generator 11. As a result, in the EH tuner 10, the drive mechanism (not shown) of the plunger 10d built in each of the E branch 10b (FIG. 6) and the H branch 10c is controlled, and the position of the microwave reflection surface of the plunger 10d changes the plasma density distribution. Move in the direction of homogenization. Further, in the microwave generator 11, its output adjusting mechanism is controlled so that the microwave power introduced into the vacuum container 1 is kept constant by compensating for the change in the reflected wave in the EH tuner 10. This control process is repeated until a uniform plasma density distribution is achieved.

FIG. 2 shows a second embodiment of the present invention. A plurality of luminescence intensity meters 17 for measuring the luminescence intensity of plasma light are provided on the wall of the vacuum container 1 so that the direction of lighting of the probe is perpendicular to the diameter of the substrate 2, and a measurement signal of the luminescence intensity is provided. Is input to the controller 15. The subsequent control steps are the same as in the case of the first embodiment. FIG. 3 shows a third embodiment of the present invention. In this embodiment, the substrate transfer hand 12
A plurality of Faraday cups 16 are arranged side by side in a row on the above, and the ion current incident on the Faraday cups 16 at each position is sent to the controller 15 to obtain the plasma density distribution. The subsequent control steps are the same as in the case of the first embodiment.

[0012]

According to the present invention, since the plasma processing apparatus is an apparatus that enters into the surface treatment step of the substrate to be processed after the above-described control is performed, the plasma density distribution of The processing is performed in the state where the uniformity is ensured, the yield of the processing results is improved, and the throughput is improved. Moreover, in particular, in the case where the probe and the Faraday cup are used for measuring the plasma density distribution, since the substrate transfer hand is used, the mechanism newly added to the apparatus for controlling the plasma density distribution is minimized, The above effect can be obtained without impairing reliability and economical efficiency.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an entire apparatus showing a plasma processing apparatus according to a first embodiment of the present invention.

2A and 2B are views showing a plasma processing apparatus according to a second embodiment of the present invention, wherein FIG. 2A is a partial cross-sectional view of the entire apparatus, and FIG. 2B is a front view of a main part of the apparatus.

FIG. 3 is a partial sectional view of the entire apparatus showing a plasma processing apparatus according to a third embodiment of the present invention.

FIG. 4 is a diagram showing an example of measurement of in-plane density distribution of microwave discharge plasma on a film formation substrate in a conventional plasma processing apparatus.

FIG. 5 is a diagram showing an example of measurement of film thickness distribution during film formation in a conventional plasma processing apparatus.

FIG. 6 is a partial cross-sectional view of the entire apparatus showing a configuration example of a conventional plasma processing apparatus.

FIG. 7 is a perspective view showing an external structure of an EH tuner that constitutes a part of the microwave transmission line and adjusts the impedance of the microwave transmission line.

8A and 8B are diagrams showing an internal structure of an E branch and an H branch of an EH tuner, wherein FIG. 8A is a front view of each branch, and FIG. 8B is a side sectional view.

[Explanation of symbols]

 1 Vacuum Container 2 Substrate (Substrate to be Processed) 4 Microwave Transmission Window 7 Microwave Transmission Section 8 Microwave Transmission Section 9 Microwave Transmission Section 10 EH Tuner 12 Substrate Transfer Hand 14 Probe 15 Control Device 16 Faraday Cup 17 Luminescence Intensity Meter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location H05H 1/16 9014-2G

Claims (4)

[Claims] 1. A vacuum container, which is formed in a cylindrical shape and has a microwave introduction port hermetically closed by a plate-shaped microwave transmission window on one end surface thereof, a microwave generator, a vacuum container and a microwave generator. A microwave oscillated by a microwave generator, which is provided with an EH tuner which is coupled to a device and constitutes a part of a microwave transmission line formed of a hollow conductor through which microwaves are transmitted, and which adjusts impedance of the transmission line. A plasma processing apparatus for introducing microwaves into a vacuum container through a microwave transmission path through a microwave transmission path, generating microwave discharge plasma in the vacuum container, and performing surface treatment of a substrate to be processed in the vacuum container. In, the in-plane plasma density distribution of the microwave discharge plasma on the substrate to be processed is automatically measured by a luminescence intensity meter attached to a plurality of positions on the wall of the vacuum container. E from the measured plasma density distribution
A plasma processing apparatus, wherein the H tuner and the microwave generator are automatically controlled to automatically control the nonuniformity of the plasma density distribution to be a predetermined value or less, and then the processing step of the substrate to be processed is started. 2. A vacuum container, which is formed in a tubular shape and has a microwave introduction port hermetically closed by a plate-shaped microwave transmission window on one end surface, a microwave generator, a vacuum container and a microwave generator. A microwave oscillated by a microwave generator, which is provided with an EH tuner which is coupled to a device and constitutes a part of a microwave transmission line formed of a hollow conductor through which microwaves are transmitted, and which adjusts impedance of the transmission line. A plasma processing apparatus for introducing microwaves into a vacuum container through a microwave transmission path through a microwave transmission path, generating microwave discharge plasma in the vacuum container, and performing surface treatment of a substrate to be processed in the vacuum container. In the in-plane plasma density distribution of the microwave discharge plasma on the substrate to be processed, the substrate transfer hand is measured by a probe attached to the substrate transfer hand. Automatic measurement is performed while moving in the diametrical direction of the substrate to be processed, and the EH tuner and the microwave generator are automatically controlled based on the measured plasma density distribution so that the nonuniformity of the plasma density distribution is below a predetermined value. A plasma processing apparatus, characterized in that, after being controlled, a processing step of a substrate to be processed is started. 3. A vacuum container, which is formed in a tubular shape and has a microwave introduction port hermetically closed by a plate-shaped microwave transmission window on one end face, a microwave generator, a vacuum container and a microwave generator. A microwave oscillated by a microwave generator, which is provided with an EH tuner which is coupled to a device and constitutes a part of a microwave transmission line formed of a hollow conductor through which microwaves are transmitted, and which adjusts impedance of the transmission line. A plasma processing apparatus for introducing microwaves into a vacuum container through a microwave transmission path through a microwave transmission path, generating microwave discharge plasma in the vacuum container, and performing surface treatment of a substrate to be processed in the vacuum container. In, the in-plane plasma density distribution of the microwave discharge plasma on the substrate to be processed is automatically measured by a Faraday cup attached to the substrate transfer hand. , Automatically controlling the EH tuner and the microwave generator based on the measured plasma density distribution so that the nonuniformity of the plasma density distribution becomes a predetermined value or less, and then entering the processing step of the substrate to be processed. A plasma processing apparatus characterized by the above. 4. The plasma processing apparatus according to claim 3, wherein a plurality of Faraday cups are attached to the substrate transfer hand, and the substrate transfer hand is stationary to automatically measure the plasma density distribution. Plasma processing equipment.