JPS62263637A - Magnetron etching device - Google Patents

Abstract

PURPOSE:To equalize plasma density by generating a magnetic field formed in front of a cathode for a magnetron etching device by a pair of main magnets on the outside and at least a pair of sub-magnets on the inside. CONSTITUTION:A distance between main magnets 6, 6 is set in 350mm and a distance between sub-magnets 8, 8 in 250mm. Accordingly, a pair of sub- magnets such as a pair of the sub magnets 8, 8 are mounted on the inside in addition to a pair of main magnets such as a pair of the main magnets 6, 6 on the outside, thus generating only a deviation to 500 Gauss from 650 Gauss as shown in the curve B, then also increasing magnetic flux density at a central section, provided that an approximately equal magnetic field can be acquired. Shafts such as screw shafts 12, 13 are fitted to the magnets in order to adjust the spaces l1, l2 of the main and sub-magnets.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetron etching apparatus for dry etching engineered O substrates and other substrates using a magnetron method.

Conventionally, as an etching method for IQ substrates, a reactive gas is decomposed in plasma, and the generated ions are used to etch the substrate provided as a cathode. Because the speed is low, processing efficiency is poor, and 1t1 is released again! Since the pressure is high, the energy of ions incident on the substrate increases, which is undesirable because it causes crystal defects and contaminants to enter the substrate.

These inconveniences can be solved by a magnetron etching method in which etching is performed by forming a magnetic field in front of the cathode to converge the plasma.

(Problem to be solved by the invention) However, in the magnetron etching method, the magnetic field in front of the cathode is not uniform, which causes the density of the converged plasma to be non-uniform, and as a result, the plasma is heated by the inrush of ions. Since the etching depth of the substrate is non-uniform, it is difficult to form fine C circuits or to etch a substrate with a large diameter.

It is an object of the present invention to solve these problems of the magnetron etching method.

(Means for Solving the Problems) In the present invention, a magnetic field is formed in front of a cathode provided with a substrate to be etched and crosses the cathode to converge plasma. Care was taken to make the magnetic field uniform by providing a 1 m outer main magnet and at least one set of sub-magnets inside.

According to another feature of the present invention, the spacing between the magnets in each set is movable and adjustable, so that the uniform state of the magnetic field can be adjusted.

(Function) After evacuating a vacuum chamber in which a cathode with a substrate on the front and a counter electrode facing the same are installed, when power is applied to the cathode from a high frequency power source, the cathode and the counter electrode facing the ground, for example, are Plasma is generated between the fc pole, and the plasma is formed in front of the cathode by a pair of main magnets on the outside and a set of sub-magnets on the inside, and the plasma is approximately uniform in fc.
It seems that it converges to an approximately uniform density in a magnetic field. When the plasma density becomes uniform, the ions generated in the plasma rush into the substrate in front of the cathode almost uniformly and perform an etching action, making it possible to perform etching with good uniformity, even for large-diameter substrates. Etches with good uniformity.

Furthermore, since the spacing between the magnets in each set can be set to 4, the plasma density can be adjusted by moving the magnets, which is convenient for use.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 and 2 of the attached drawings. A vacuum chamber (3) equipped with an exhaust port (2) connected to a vacuum pump with the symbol fil F'i; is the vacuum chamber (1)
The cathode is installed so that the front side (S) is exposed inside.
4) is a counter electrode provided in the vacuum chamber (1) in parallel with the cathode (3) and has a ground potential, and (5) is a high frequency power source connected to the cathode (3). Mano (61+61
is an outer I Mi made of rare earth, e.g. 5n-Go, which generates a magnetic field (7) in front of the cathode (3).
, the main magnet, +81 (8) indicates a pair of sub magnets provided inside the main magnet +61 (61), and the sub magnet (81
(81 is made of the same rare earth material as the main magnet (6), and it is also possible to arrange multiple sets inside the main magnet (61+6) if necessary. (9) The cathode is used to perform Fi etching. A substrate such as a silicon wafer, (1 (1 (1G) is a pole piece, (11)
is a yoke material on which the main and sub magnets (6) and (8) are arranged.

In the one shown, the distance between main magnet +61 and +6+ is 350m5
, the sub magnet (81 (the space between 81 is set to 2501). If only the main magnet +61 (6) is provided like the conventional one, the magnetic flux density of the magnetic field formed in front of the cathode (3) is As shown by curve A in Fig. 3, it varies greatly from 1000 Gauss at the periphery to 300 Gauss at the center, but as in the case of the present invention, one set of main magnets on the outside (
In addition to 61+6+, for example, one set of sub magnets +8 inside it.
By providing 1 (8), the deviation only occurs from 650 Gauss to 500 Gauss as shown by curve %B in Figure 3, and the magnetic flux density at the center can also be increased, resulting in an approximately uniform magnetic field. Using the surface mold of the present invention, a thermal oxide film on a 6-inch silicon wafer substrate was etched using O74 etching gas at α075 torr at a flow rate of 30,500 M.
When etched with a high frequency power density of W/ffl,
The thermal oxide film is etched at an etching rate of 5500 A/min, and the etching deviation it±a, s% ensures uniformity and good etching. Note that the spacing between the main and sub magnets Is -1* In order to adjust K, for example, a screw shaft α21 (131) is provided on the magnet.

(Effects of the Invention) As described above, according to the present invention, the magnetic field formed in front of the cathode of the magnetron etching device is
Since the magnetic field is generated by a set of main magnets, at least one set of sub-magnets on the inside, and K, a magnetic field with a uniform magnetic flux density can be obtained, and the plasma density can be made uniform. Therefore, etching with good uniformity can be performed. It has the advantage that it can be conveniently applied to etching large-diameter substrates.

6<+l Q-Ishi no Mait) /, ,β,
By irradiating A, the plasma density Ll m
You can also do

[Brief explanation of drawings]

FIG. 1 is a cut screen diagram of an embodiment of the present invention, FIG. 2 is a plan view of the section taken along line 1-1 in FIG. 1, and FIG. 3 is a diagram of the magnetic flux density in front of the cathode. (1)...Vacuum chamber (3)...Cathode+
61 [61... Main magnet (7)... Magnetic field +
8) (81...Sub-magnet (9)...Substrate type Engineer: Kin Kitamura 〒 ゛、：2 others)

Claims (1)

[Claims] 1. In a cathode in front of which a substrate to be etched is provided, a magnetic field is formed across the cathode to converge plasma. A magnetron etching apparatus characterized in that a set of main magnets and at least one set of sub-magnets inside the set are provided to create a uniform magnetic field. 2. The magnetron etching apparatus according to claim 1, wherein the spacing between each set of magnets is movable and adjustable.