JPH05267244A - Method and apparatus for plasma treatment - Google Patents

Abstract

PURPOSE:To enable plasma treatment of high treatment speed and high shape controllability by bringing pressure conditions of sub and main treatment chambers in a vacuum chamber and the activation of etching power and deposi tion power into an optimum state. CONSTITUTION:A vacuum chamber 10 is divided by a partition plate 13 to activate the etching gas sufficiently in a sub treatment chamber 14, and the activated gas is doped with a deposition gas, sent to a main treatment chamber 15, and further excited into plasma. The sub treatment chamber 14 keeps a pressure optimum for generating the activation species at a pressure higher than that of the main treatment chamber 15 and activates etching power sufficiently. On the other hand, the deposition gas is supplied to downstream of the gas flow in the sub treatment chamber 14, shortens excitation time, and suppresses activation. The main treatment chamber 15 keeps an optimum pressure for exhausting reaction products to subject substrates to plasma treatment. This process can make plasma treatment of high treatment speed and high shape controllability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing method and apparatus, and more particularly to a plasma processing method and apparatus suitable for processing a substrate such as a semiconductor integrated circuit substrate using plasma.

[0002]

2. Description of the Related Art As a conventional device, for example, Japanese Patent Laid-Open No.
As described in JP-A-162591, another gas is supplied by activating a gas in an activation chamber by a microwave and feeding the gas between parallel plate electrodes in a processing chamber through a transfer pipe, and supplying the gas between the parallel plate electrodes. The inside of the processing chamber is set to a predetermined pressure with the gas from the space, high frequency power is applied between the parallel plate electrodes to generate plasma, and the substrate is processed by the plasma, and a large amount of active species is generated by ionization in the activation chamber. There is a method in which the processing speed of the substrate can be improved even in a relatively low pressure region by sending the gas contained in the gas between the parallel plate electrodes.

Further, as described in JP-A-2-83921, a discharge tube is provided in a waveguide, and a processing gas in the discharge tube is converted into plasma by microwaves to etch a sample. An insulating container is provided on the outside of the chamber, the processing gas is introduced between the outer insulating container and the discharge tube, and the processing gas is evenly distributed toward the sample from a plurality of gas discharge holes provided on the apex of the discharge tube as axial targets. Some of them are released to improve the uniformity of plasma treatment of the sample.

[0004]

At present, in order to prevent a reaction product, which causes a decrease in etching rate, from staying in the processing chamber for a long time, the flow of gas, the exhaust rate is increased, the gas flow rate is increased, and the processing is performed. Various studies have been carried out such as lowering the pressure of the chamber.However, when the exhaust speed is increased, the residence time of the reaction products in the processing chamber is reduced and the residence time of etching gas, etc. is also reduced, and the amount of active species produced is reduced. However, there is a problem that the processing speed cannot be sufficiently improved. Further, in the etching using the deposition gas for forming the sidewall protective film for shape control, the deposition gas is not sufficiently dissociated due to the decrease in the processing chamber residence time, and a large amount of deposition gas is generated. It had to be introduced, and there was a problem of leading to an increase in the size of the exhaust system.

Incidentally, the above-mentioned prior art, JP-A-3-1625.
No. 91 and JP-A No. 2-83921 consider the etching characteristics when a deposition gas for forming a side wall protective film is used as a processing gas, particularly the etching rate and shape. Not not.

An object of the present invention is to provide a plasma processing method and apparatus with high processing speed and good shape controllability.

[0007]

The above-mentioned object is to partition a vacuum chamber, to which an etching gas and a deposition gas are supplied and whose inside is evacuated under reduced pressure, by providing conductance with a partition member through which these gases can pass. A sub-treatment chamber is formed on the upstream side of the gas flow, a main treatment chamber is formed on the downstream side, and a sample stand for arranging the sample corresponding to the gas passage hole of the partition member is provided in the main treatment chamber, A device provided with means for activating the gas in the sub-treatment chamber and means for plasmaizing the gas in the main treatment chamber, and conductance between the sub-treatment chamber to which the gas is supplied and the main treatment chamber for processing the sample. To separate the vacuum chamber, excite the etching gas supplied to the sub-process chamber, add the deposable gas to the activated gas, send the gas with the deposable gas to the main process chamber, and further excite the gas. Into plasma Te, by a method of etching a sample by using the plasma, it is achieved.

[0008]

[Operation] A sub-processing chamber and a main processing chamber are provided in the processing chamber by providing conductance, the etching gas is sufficiently activated in the sub-processing chamber side, and the deposition gas is added to the activated etching gas. To the main processing chamber and further excited to turn it into plasma. The sub-process chamber is kept at a pressure higher than that of the main process chamber, which is optimum for the generation of active species, and the etching gas is sufficiently activated. On the other hand, the deposition gas is supplied on the downstream side of the gas flow in the sub-processing chamber to shorten the excitation time and suppress the activation. In the main processing chamber, the substrate is plasma-processed while maintaining the optimum pressure for exhausting the reaction products. As a result, it is possible to prevent an excessive amount of reaction products generated by the deposition gas in the main processing chamber,
The substrate can be processed at a high processing speed with good shape controllability.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a plasma processing apparatus of the present invention, in this case, a magnetic field microwave etching apparatus. In this case, the vacuum chamber 10 has a cylindrical upper central portion formed in a concave shape, a donut-shaped disk partition plate 13 is provided inside the vacuum chamber 10, and an auxiliary vacuum chamber 14 is provided above the vacuum chamber 10. And the main vacuum chamber 15 is formed in the lower part. The upper part of the vacuum chamber 10 and the partition plate 13 that form the sub-processing chamber 14 are made of quartz, and can transmit microwaves. A partition plate 13 is provided in the main processing chamber 15 of the vacuum chamber 10.
A sample table 11 is provided so that the processing surface of the wafer 12, which is a sample, can be arranged corresponding to the central opening of the. A gas inlet 16 for supplying an etching gas is connected to the upper end of the sub processing chamber 14 and is connected to a gas source (not shown). A gas inlet 17 for supplying a deposition gas is connected to the lower portion of the sub processing chamber 14,
It is connected to another gas source not shown. An exhaust port 18 for evacuating the inside of the main processing chamber 15 is provided in the lower part of the main processing chamber 15 and is connected to an exhaust device (not shown). Vacuum chamber 10
Outside of the above, at least the outer periphery and the upper portion of the sub processing chamber 14 are covered with the waveguide 19, and the microwave can be propagated inside the sub processing chamber 14 and the main processing chamber 15. In this case, a solenoid coil 20 is wound around the outside of the vacuum chamber 10 with the waveguide 19 interposed therebetween. A predetermined conductance is provided by the partition plate 13 between the main processing chamber 15 and the sub processing chamber 14 so that the main processing chamber can be set to an optimal pressure for processing the wafer 12, while the sub processing is performed. The processing chamber 14 is set to have a pressure condition suitable for activating the etching gas.

With the apparatus configured as described above, the main processing chamber 15 is provided in the upper sub-processing chamber 14 with gas introduction ports 16 and 17.
By holding and evacuating from the bottom with a vacuum exhaust device,
For example, the pressure is kept at 2 to 3 mTorr. Main processing room 1
A microwave electric field is introduced into the inside of 5 by the waveguide 19, a magnetic field is formed by the solenoid coil 20, plasma is generated by the discharge by these actions, and the semiconductor integrated circuit on the sample stage 11 is patterned by the plasma. The etching process is performed on the wafer 12. At this time, the processing gas is introduced into the main processing chamber 15 through the sub processing chamber 14, but since the sub processing chamber 14 is connected to the main processing chamber 15 through the gap between the partition plate 13 and the bottom surface of the recess. The pressure in the sub processing chamber 14 is higher than that in the main processing chamber 15 due to the conductance in the gap, and is maintained at, for example, several tens mTorr. Further, the processing gas in the sub-processing chamber 14 is excited and activated by the action of the microwave electric field introduced by the waveguide 19 and the magnetic field formed by the solenoid coil 20. The size of the sub processing chamber 14 and the conductance with the main processing chamber 15 are adjusted so that an appropriate amount of active species can be generated. The active species generated in the sub processing chamber 14 are introduced from the central portion into the main processing chamber 15 through the opening of the partition plate 13.

In this embodiment, as the processing gas, an etching gas is introduced from the gas inlet 16 and a deposition gas for controlling the etching shape is introduced from the gas inlet 17. For example, when etching a silicon oxide film, CF ₄ is used as an etching gas and CHF ₃ is used as a deposition gas. The etching gas introduced from the gas introduction port 16 stays in the sub-treatment chamber 14 for a long time and is therefore sufficiently excited and activated. on the other hand,
The deposition gas introduced from the gas inlet 17 is
The excitation is for a shorter time than the etching gas. This prevents the deposition gas from unnecessarily staying in the sub-treatment chamber 14 and being activated, and
The inside of the main processing chamber 15 is prevented from being polluted, and the excessive deposition gas in the main processing chamber 15 is prevented from being converted into plasma, so that the generation of the reaction product due to the deposition gas is suppressed and the reaction product due to the etching gas is removed. It is designed to improve exhaust efficiency.

As a result, as shown in FIG. 2, the processing pressure is conventionally lowered to sacrifice the etching rate to secure the shape, and the pressure is increased to sacrifice the shape to secure the etching rate. In addition, it was possible to suppress the generation of reactive products due to the deposition gas and to efficiently exhaust the reactive products during etching, and to sufficiently activate the etching gas in the sub-processing chamber 15. By promoting the reaction by the plasma in the planned main processing chamber 15, it is possible to improve the etching rate while ensuring a highly accurate shape as in the present invention.

As described above, according to this embodiment, it is possible to prevent the deposition gas from being excessively activated and to sufficiently etch the etching gas. Therefore, it is possible to perform etching with high shape controllability at a high processing rate. Processing can be performed.

Next, a second embodiment of the present invention will be described with reference to FIG. 2, the same reference numerals as those in FIG. 1 indicate the same members, and the description thereof will be omitted. This drawing differs from FIG. 1 in that the sub-processing chamber 1
A microwave shielding plate 21 is provided on the inner wall side of the recess of 4a,
An electrode 22 is provided on the outer wall surface of the sub processing chamber 14a, and a high frequency power source 23 is connected to the electrode 22. The shield plate 21 is connected to the waveguide 19 and has a ground potential.

In the apparatus thus constructed, the shield plate 21
The microwave is prevented from entering the sub-treatment chamber 14a by the high-frequency power applied to the electrode 2
The etching gas and the deposition gas in 4a are activated. The gas activated in the sub processing chamber 14a enters the main processing chamber 15 and is turned into plasma by the action of the microwave from the inside of the waveguide 19 and the magnetic field of the solenoid coil 20. As a result, in addition to the effect of the one embodiment, in the Sara processing sub-chamber 14a, sufficient high-frequency power is applied regardless of the microwave power to more efficiently generate active species of the etching gas. You can

Next, a third embodiment of the present invention will be described with reference to FIG. 4, the same reference numerals as those in FIG. 1 indicate the same members, and the description thereof will be omitted. This drawing is different from FIG. 1 in that the vacuum chamber 10
a is formed into a cylindrical shape, and the upper surface of the vacuum chamber 10a is provided with a quartz window 24a.
The quartz-made cylindrical partitioning cylinder 25 is installed in the vacuum chamber 10a, the sub-processing chamber 26 is formed outside the partitioning cylinder 25, and the main processing chamber 27 is formed inside the partitioning cylinder 25. ,
A gas inlet 1 for the etching gas is provided below the sub processing chamber 26.
6a are connected, a gas introduction port 17a for deposition gas is connected to the upper side of the sub-processing chamber 26, an exhaust port 18a is provided to the lower part of the main processing chamber 27, and conductance is provided between the quartz window 24 and the partition cylinder 25. That is, a plurality of openings for introducing the activation gas into the main processing chamber 27 are provided on the upper surface of the partition cylinder 25.

According to the apparatus configured as described above, the processing gas in the sub processing chamber 26 is excited and activated by the action of the microwave from the inside of the waveguide 19 and the magnetic field of the solenoid coil 20. The activated processing gas in the main processing chamber 27 is the microwave and the solenoid coil 2.
It is turned into plasma by the action of a magnetic field of zero. As a result, the same operation and effect as in the above-described embodiment can be obtained, and since the auxiliary processing chamber 26 and the main processing chamber 27 have the same height, the height of the vacuum chamber 10a can be reduced and the apparatus can be downsized. There is.

In this embodiment, only the etching process is described as the plasma process, but it can be applied to the process such as film formation depending on the combination of process gases.

[0019]

According to the present invention, the vacuum chamber is partitioned by the partition plate, and the pressure conditions of the sub-processing chamber and the main processing chamber and the activation of the etching gas and the deposition gas can be optimized. Therefore, there is an effect that plasma processing with good shape controllability can be performed at a high processing speed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a magnetic field microwave etching apparatus which is an embodiment of a plasma processing apparatus of the present invention.

FIG. 2 is a diagram showing etching performance when processed by the apparatus of FIG.

FIG. 3 is a vertical sectional view showing a magnetic field microwave etching apparatus which is a second embodiment of the plasma processing apparatus of the present invention.

FIG. 4 is a vertical cross-sectional view showing a magnetic field microwave etching apparatus that is a third embodiment of the plasma processing apparatus of the present invention.

[Explanation of symbols]

10, 10a ... Vacuum chamber, 11 ... Sample stage, 13 ... Partition plate,
14, 14a, 26 ... Sub processing chamber, 15, 27 ... Main processing chamber, 19 ... Waveguide, 23 ... High frequency power source, 24 ... Quartz window,
25 ... Partition cylinder.

Claims (5)

[Claims] 1. A vacuum chamber is divided by providing conductance between a sub-processing chamber to which gas is supplied and a main processing chamber for processing a sample, and the etching gas supplied to the sub-processing chamber is excited and activated. Deposition gas is added to the gas, and the gas to which the deposition gas is added is sent to the main processing chamber,
A plasma processing method, which further comprises exciting the material into plasma, and etching the sample using the plasma. 2. A vacuum chamber in which an etching gas and a deposition gas are supplied and the inside of which is decompressed and evacuated is partitioned by a conductance member provided with a partition member that allows the gas to pass therethrough, and is partitioned upstream of the flow of the gas. A sub-processing chamber is formed, a main processing chamber is formed on the downstream side, and a sample table for arranging a sample corresponding to the gas passage hole of the partition member is provided in the main processing chamber. A plasma processing apparatus comprising: a means for activating gas and a means for converting gas in the main processing chamber into plasma. 3. A microwave is used as a means for activating the gas in the sub-processing chamber and a means for plasma-converting the gas in the main processing chamber, and the sub-processing chamber is arranged in a traveling direction of the microwave. Is provided on the outer peripheral portion of the vacuum chamber in front of the main processing chamber, the etching gas is supplied on the front side in the traveling direction of microwaves of the sub-vacuum chamber, and the deposition gas is the sub-vacuum. The plasma processing apparatus according to claim 2, wherein the plasma is supplied on the rear side with respect to the traveling direction of microwaves in the chamber. 4. The means for activating the gas in the sub-processing chamber uses high-frequency power, and the means for plasma-converting the gas in the main processing chamber uses microwaves, and the sub-processing chamber is the vacuum chamber. 3. The etching gas is provided on the upstream side of the gas flow in the sub vacuum chamber, and the deposition gas is supplied to the downstream side of the gas flow in the sub vacuum chamber. Plasma processing equipment. 5. A microwave is used as the means for activating the gas in the sub-processing chamber and the means for plasma-converting the gas in the main processing chamber, and the sub-processing chamber is provided at the outer peripheral portion of the vacuum chamber. The main processing chamber is provided inside the sub processing chamber, the etching gas is supplied upstream of the gas flow in the sub vacuum chamber, and the deposition gas is the gas flow in the sub vacuum chamber. The plasma processing apparatus according to claim 2, wherein the plasma processing apparatus supplies the gas to the downstream side.