JPS61120422A - Method of treating with plasma - Google Patents

Abstract

PURPOSE:To improve the uniformity of treatment in a material to be treated, by changing the correlation between the directions of electric field and of magnetic flux during the plasma treatment in accordance with a treating speed in the material. CONSTITUTION:When glow discharge is caused to occur between upper and lower electrodes 10 and 11 for producing plasma, the produced plasma becomes stronger in the central region where magnetic flux and electric field intersect orthogonally while weaker in the end regions. If a magnet element 17 is inclined to the direction of the electric field by an angle theta, the region having stronger plasma is shifted from the center toward the end. By appropriately setting an angle theta and a treating time, the concentrations of plasma from the center to the ends can be controlled as required. Accordingly, the treating speed of a semiconductor substrate 40 can be uniformized by providing stronger plasma in the central region or in the peripheral region in this manner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a plasma processing method, and particularly to a plasma processing method, in which gas under vacuum is turned into plasma under the action of an electric field and a magnetic field, and ions or The present invention relates to a plasma processing method for processing a sample with active species.

[Background of the invention]

The technique of turning gas under vacuum into plasma by glow discharge using an electric field and treating a sample with ions or active species in the plasma is used for various purposes such as modification and processing of the sample surface, as well as deposition of substances on the sample surface. used in the field of

On the other hand, when a magnetic field is applied to a glow discharge caused by an electric field, an electric Ron force and an electromagnetic Lorentz force act, and especially if the electric field and the magnetic field are orthogonal to each other, charged particles make a cycloidal motion.

This increases the frequency of collisions between particles or molecules, increases the density of ions or active species, and improves sample processing speed.

Such a plasma processing technology that uses both an electric field and a magnetic field is particularly effective in use in sputtering technology, dry etching technology, and vapor phase growth technology for processing silicon semiconductor and compound semiconductor substrates. (Tokuko Sho 54-3263
On the other hand, in dry etching techniques, etc., the sample processing speed has a radial distribution within the sample. For example, in M dry etching, There is a tendency for the processing speed to be high in the middle and slow in the middle.

The above-mentioned conventional plasma processing technology that uses both an electric field and a magnetic field can improve the processing speed of the sample, but the processing speed within the sample is non-uniform, which reduces the uniformity of the processing within the sample. There are still problems with .

[Purpose of the invention]

An object of the present invention is to provide a plasma processing method that uses both an electric field and a magnetic field, which can improve the uniformity of processing within a sample by improving the non-uniformity of processing speed within the sample.

[Summary of the invention]

The present invention is characterized by changing the correlation between the direction of an electric field and the direction of magnetic lines of force of a magnetic field during processing of a sample, depending on the processing speed within the sample. This is an attempt to improve.

[Embodiments of the invention]

In plasma processing techniques that use magnetic elements in combination with electromagnetic fields, the strongest plasma is generated where the electric and magnetic fields are perpendicular to each other. In the magnet elements actually used, the lines of magnetic force of the magnetic field are curved, and the strongest plasma is generated where the component perpendicular to the electric field is large. Based on these facts, the present invention changes the correlation between the direction of the electric field and the direction of the magnetic lines of force of the magnetic field during sample processing according to the processing speed within the sample,
For example, non-uniformity in processing speed within a sample is improved by generating the strongest plasma corresponding to the location within the sample where the processing speed is lowest.

An embodiment of the present invention will be described with reference to FIGS. 1 to 3 in the case where the sample is a semiconductor substrate and the semiconductor substrate is subjected to a dry etching process.

In FIG. 1, the dry etching apparatus is a vacuum vessel main body which houses two discharge electrodes, an upper electrode W and a lower electrode (2), which are parallel to each other, and has a gas supply hole 13 and a semiconductor substrate loading hole 14. and a magnet element 17 that is rotated and oscillated around the rotating shaft 16. Here, the upper electrode IO is attached to the vacuum vessel 3 via an insulator, and the lower electrode IO is attached to the vacuum vessel 3 via an insulating material. Iu
is attached via an insulating section 19 to an electrode support material m that constitutes a part of the vacuum chamber. Magnet element 17 has N pole 9 on one side
The dry etching apparatus is configured such that one side thereof is SS, and is supported in a state where it can rotate and oscillate as shown by the arrow I by the rotation and oscillation means B. The operation of the dry etching apparatus configured in this way will be explained below. .

Gas necessary for etching the semiconductor substrate is supplied from the supply hole and exhausted from the exhaust hole 13, and when power is applied to the lower electrode U from a high-frequency power source (not shown), the gas flows between the upper and lower electrodes 10 and 11. A glow discharge occurs and plasma is obtained. As detailed in Figure 2, the state of plasma is as follows: a strong plasma occurs at the center where the electric field and magnetic lines of force intersect at right angles (indicated by XXX marks), and as it goes to both ends, the lines of magnetic force bend, and the upper and lower components of the magnetic flux density (parallel to the electric field) occur. The plasma becomes weaker as the components (components) become stronger. On the other hand, as shown in FIG. 3, when this magnet element 17 is rotated in the θ direction with respect to the direction of the electric field, the lines of magnetic force also rotate accordingly, and the areas where the plasma is strong move from the center to the edges.

Therefore, by appropriately setting the relationship between the rotation angle θ and the processing time, it is possible to freely control the density of the plasma from the center to the edges, and as in AJ, the etchant concentration becomes rate-determining and the processing speed in the periphery increases. By increasing the strength of the plasma in the center for processes that tend to occur, or conversely, by increasing the strength of the peripheral plasma for processes where the processing speed at the center is too high, we can reduce the non-uniformity of processing speed within the semiconductor substrate ψ. It is possible to improve the uniformity of processing within a semiconductor substrate.

An embodiment of the present invention has been described above for the case of dry etching, but even if the following changes occur, there is no difference in the effect of the present invention in terms of wood quality, and therefore, they are naturally included in the present invention. It is something.

(1) When the power applied to the discharge electrode is high frequency, low frequency, or direct current (2) When the electrode to which the above power is applied is the lower electrode or upper electrode (3) When the lower electrode is (If it forms part of a vacuum device, if it is configured as an independent electrode inside a vacuum!Jf, if it is an active gas, or if it is a mixture of both gases. (5) Plasma treatment schedule In the case of dry etching, in the case of sputtering, in the case of vapor phase growth, in the case of supply from the lower surface of the upper electrode, and in the case of supply from the upper surface of the lower electrode and the lower peripheral edge of the material to be processed (7 ) When the upper and lower electrodes are temperature-controlled and when they are not (8) When the temperature of the substance to be treated is controlled and when it is not [Effects of the Invention] As explained above, the present invention solves the Since the uniformity can be improved, there is an effect that the uniformity of processing within the sample can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a vacuum container section showing an example of a dry etching apparatus embodying the present invention, the second factor. FIG. 3 is a conceptual diagram showing the state of the magnet element and plasma in FIG. 1. 10... Upper electrode, 11... Lower electrode, 6
Song: Vacuum container, 17...Magnetic element, Mu...
...Rotating swing means, 40...Semiconductor device

Claims (1)

[Claims] 1. In a method in which a gas under vacuum is turned into plasma under the action of an electric field and a magnetic field, and a sample is treated with ions or active species in the plasma, the direction of the electric field and the A plasma processing method characterized by changing the correlation between a magnetic field and the direction of magnetic lines of force according to the processing speed within a sample.