JPS5855569A - Plasma etching method - Google Patents

Abstract

PURPOSE:To prevent the adhesion of foreign matters onto a surface to be etched, by carrying out plasma etching through an inclined magnetic field formed toward the central part of an electrode opposed to the end part of an electrode mounting an object to be treated in a plasma region having parallel electrodes. CONSTITUTION:To the peripheral flange part of the plasma region 9 of a plasma etching apparatus having a conventional structure, plural rod magnets having, for example, an inclination angle of about 30-60 deg. toward the center from the peripheral flange part of a lower electrode 2 are radially arranged and an inclined magnetic field is formed toward the central part of an upper electrode 3 from the electrode 2. In this condition, on a Cr film 11 deposited and formed on the surface of a glass base plate on the electrode 2, a substrate 8 to be treated having a resist mask pattern 12 formed thereon is mounted. Subsequently, CCl4 atmosphere with about 10<-2>-10<-4> Torr is held in an etching chamber 1 and plasma is generated between the upper and the lower electrodes by high frequency power to selectively etch the film 11. During this time, a fine segmental deteriorated resist substance scattered from the surface of the pattern 12 is mostly dropped to the peripheral part of the electrode 2 along the magnetic field 16 and the dropping and the deposition thereof to the etching surface is reduced to a large extent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plasma etching method, and more particularly to a plasma etching method (parallel plate plasma etching,
This invention relates to improvements in secondary etching (including ivy etching and reactive ion etching).

As the density of integration in semiconductor devices progresses,
As an etching means for forming fine patterns with high precision, plasma etching using an etching apparatus having parallel planar electrodes, such as reactive ion etching, has come to be widely used.

The first diagram shows the cross-sectional structure of the main parts of a conventional glue active ion etching device. 1 is the etching chamber, 2 is the lower electrode to which high frequency power is applied, 3 is the upper electrode to be grounded, and 4 is the exhaust system. , 5 is an etching gas introduction pipe, eV
i High frequency power supply, f is ground, 8 is the substrate to be processed, 9 is guts! It represents an area.

However, in the conventional glue active ion etching method using such etching equipment, the resist mask film fragments (these fragments are composed of radicals or ions) are crushed and scattered by the impact of radicals or ions. The etching resistance is extremely high as the etching resistance has been altered by being hit by ions), but it adhered to the etched surface and inhibited etching9, and also contaminated the etched surface. The schematic cross-sectional view shown in FIG. 2 shows this state in an example of the selective etching process when manufacturing a chrome mask. In the figure, 2 is the lower electrode, 10 is the glass substrate, 11
is a chromium film, 12 is a resist mask pattern, 13 is carbon tetrachloride bulk radical (CCja'') and chlorine ion (C
J-), etc., 14 indicates a thin piece of the resist alteration, and 15 indicates the range of the resist alteration. That is, strips of resist alteration 14 are scattered from between the resist mask pattern 12 excited by plasma and struck by 90C14*, C4-, etc. 13, and the resist alteration #l strips 14 are exposed. The etching of the underlying chromium film is inhibited by the resist deterioration particles 14, and a chromium film residue is formed in the mosquito area. In addition, it is difficult to remove resist denatured substances due to their unique etch resistance, so if mosquito resist denatured particles form a layer on a glass substrate from which the chromium film has been etched, the resist denatured substances will be removed. The objective of the above-mentioned conventional method is to eliminate the problems encountered in the conventional method. It is an object of the present invention to provide a plasma etching method that prevents foreign matter from adhering to etching hardening or etching completion.

That is, the present invention provides a goods master etching method using an etching device having parallel planar electrodes, in which a workpiece is placed in the goods master area from the edge of the electrode on which the object to be processed is mounted toward the center of the electrode facing the electrode. The method is characterized in that a gradient magnetic field is formed and plasma etching is performed via the magnetic field.

The present invention will be explained in detail below with reference to an embodiment of the present invention using a sectional view of the main parts of a reactive ion etching apparatus shown in FIG. As shown in Fig. 3, it has parallel planar electrodes. Use an etched lid. That is, in the wrinkle apparatus, in an etching chamber 1 to which an exhaust system 4 and an etching gas introduction pipe 5 are connected, there is a flat lower electrode 2 connected to a high frequency power source 6, and a ground 7 facing the lower scissor electrode 2. Goods with a conventional structure in which a flat upper electrode 3 is arranged. Plasma region in etching equipment, 90
In the peripheral green part, there is an axis f of about 30 to 60 [degrees] from the periphery of the lower electrode 2 to the center of the upper electrode 3. A plurality of bar magnets M having +6, for example, N and others, are arranged 1β] radially in a constant magnetic pole direction on the upper 9i pole 3 side, and the lower electrode 2 is placed in the plasma region 9 circles by the corresponding stones M. A 'ib ridge 16 is formed that slopes from the ld edge toward the center of the lower electrode 3. Note that the magnetic flux density of the La field is preferably 8 degrees, for example 5 to 20 degrees, so as not to disturb the concentration of plasma [on a glass substrate]. Further, the directions of the N and S poles of the magnet may be unified to the vertical direction. It is most efficient if the ah stone is formed into an umbrella-shaped ring. Furthermore, magnet M is a permanent magnet, K
Any L stone is fine.

For example, when manufacturing a chrome mask using the method of the present invention, a chrome film 11 having a thickness of about 300 to 500 (A) is deposited on a glass substrate 10, and a chrome mask is used. Then, a substrate 8 to be processed, on which a resist mask pattern 12 having a thickness of 7,000 (A) 111 m, for example, is formed by a normal photo process, is placed on the lower electrode 2, and etched under normal conditions, e.g., etching m1. inside 1
0-2 to 10-” (T.

For example, 1356
(MHz), 0.2 to 0.3 (W/d) i degree high frequency power generates plasma between the upper and lower electrodes and between the electrodes, and the chromium film 11 exposed between the resist mask pattern 12 selectively etched away. In the method of the present invention, a magnetic field 16 is formed in the plasma region 9, which is inclined from the periphery of the lower electrode 20 toward the center of the upper electrode 3, as described above. Therefore, it resists being hit by CCl4* and CA'-! School pattern 1
Most of the flaky resist deterioration that scatters from the two surfaces falls along the magnetic field 16 to the periphery of the lower electrode 20,
The amount of flaky resist deterioration that falls and adheres to the surface to be etched is greatly reduced. And actually, the above-mentioned altered substances cause
The defects in chrome masks caused by IIφ bites have been reduced to less than 10 compared to the conventional method.

Although the present invention is applied to reactive ion etching in the above embodiments, it can of course also be applied to plasma etching and bipolar sputter etching using the method of the present invention.

As explained above, the plasma etching method of the present invention
1K Yorewa Huo) At W Sufu! ! The occurrence rate of the four-residue pattern is reduced, and the manufacturing yield of the foot mask 6 is improved. Furthermore, by applying the plasma etching method of the present invention to the manufacture of semiconductor devices, it is possible to improve the manufacturing process as described above.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main parts of a conventional glue active fist ion etching device, and Figure 2 is an explanatory diagram of the conventional etching state.
Section 3 is a sectional view of a main part of an embodiment of an active fist ion etching device to which the present invention is applied. In the figure, 1 is the etching chamber, 2 is the lower electrode, 3 is the upper electrode, 4 is the exhaust system, 5 is the etching gas introduction pipe, 6 is the high frequency IL source, 7 is the ground, and 8 is the substrate to be processed. , 9 is the Gutsuzu i area, 16 is the Buddha field, M is the magnet, f; 7 Figure 1,000 k Figure

Claims (1)

[Claims] Load the objects to be processed! A plasma etching method characterized by forming a magnetic field that slopes from the edge of a pole toward the center of one pole facing the electrode, and etching a workpiece through the magnetic field.