JPS594028A - Manufacturing device of semiconductor - Google Patents

Abstract

PURPOSE:To obtain uniform plasma by forming gas blow-off ports in rectangles of long circumferential length while disposing a porous plate onto the gas blow- off ports in an etching device in which an upper electrode with the gas blow-off ports and a lower electrode are set up into a chamber, while a semiconductor wafer is disposed onto the lower electrode and plasma discharge is generated in the chamber. CONSTITUTION:A gas intake 2 connected to a high frequency generating section 8 while its upper end being penetrated is inserted into the chamber 7 constituting the plasma etching device, and the upper electrode 1' is set up to the lower end of the gas intake. A wide electrode section 3' with a large number of slits 4' is fitted to the electrode 1' at that time, but the slits 4' are not formed in mere holes but formed to slit shapes of comparatively long circumferential length while one porous plate 11 is set up onto the slits, and the electrode 1' is formed to a box shape. The normal lower electrode 5 is fitted to the lower section of the upper electrode 1', the wafer 9 is placed into the lower electrode, and plasma is generated between the electrodes 1' and 5. Accordingly, plasma is made uniform, and an excellent etching effect is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field of the invention The present invention relates to semiconductor manufacturing equipment, particularly plasma CV
The present invention relates to a semiconductor manufacturing apparatus having an electrode structure for D or plasma etching.

(2) Technology background In recent years, for example, polycrystalline Si, 5T
O2, PSG (bosphosilicate glass), etc. are CV
It is formed by the D method. However, since the CVD method has problems in terms of temperature resistance, flagging, etc., recently, a plasma CVD method that uses a plasma reaction, that is, causes a reaction at a low temperature to form a thin film, has been used.

(3) Prior art and problems Figures 1 (δ) to (C) show conventional plasma CVD equipment; is a plan view of the electrode section viewed from below and Figure 1
c+ shows an opening cross-sectional view, respectively.

In the figure, the upper electrode part 1 mainly consists of the gas intake rotor 1 wide electrode part 3. The gas outlet is composed of a through hole 4, etc., and is located below a lower electrode 5 on which a wafer 9 is placed for causing a predetermined chemical reaction to form a thin film, and a vacuum exhaust port 6 on the outer periphery of the lower electrode 5. is equipped with a vacuum pump (not shown) for evacuating the chamber.

The inside of the chamber 7 is maintained at a low pressure of, for example, approximately I Torr by a vacuum pump provided below the vacuum exhaust port 6, and a plasma gas, such as 3iHn, is used as a plasma gas from the gas intake port 2.

Plasma is formed by taking in a gas such as NH3 and releasing it through the gas blowing hole 4, and further applying a high frequency voltage to the upper electrode part 1 and the lower electrode 5 by the high frequency generator 8 to cause a high frequency discharge. do. A predetermined chemical reaction occurs on the wafer 9 by ions and electrons in the plasma, and a thin film grows on the wafer to form a desired semiconductor. However, in the past, the electrode part was
Edge part 1 of circular gas outlet 4 as shown in l and (C)
Since the hole 1o has a sharp shape after being drilled, when a high voltage is applied, an electric field is generated at the edge 1o of the hole, and the high-angle discharge becomes stationary and tends to cause so-called abnormal discharge. Plasma under discharge.

When CVD is performed, for example, the film thickness growth rate on the wafer 9 becomes non-uniform, resulting in uneven film thickness, or in severe cases, a gas phase reaction occurs, causing white powder to fall onto the wafer 9 and making it impossible to maintain a predetermined thin film. Growth was not possible, causing problems in semiconductor manufacturing. Note that the occurrence of the field lightning discharge described above can be suppressed to some extent by, for example, reducing the diameter of the hole provided in the electrode, but if the electrode is difficult to machine, a small aperture cannot be obtained. There were no drawbacks.

(4) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention generates uniform plasma by forming a gas blowing hole in a wide electrode part of a plasma CVD device or a plasma etching device into a slit shape. By providing a porous plate immediately in front of the slit in the electrode section, the purpose is to generate more uniform plasma and provide a better semiconductor film thickness.

(5) Structure of the Invention The feature of the present invention is that a chamber is provided with an upper electrode and a lower electrode each having a gas outlet, a wafer is placed on the lower electrode, and the chamber is filled with gas to cause plasma discharge. An object of the present invention is to provide a semiconductor manufacturing apparatus characterized in that the upper electrode is provided with an opening having an appropriately shaped opening having a large ratio of circumference to area of the gas outlet of the upper electrode.

(6) Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2+a+, (bl is a cross-sectional view showing the configuration of the semiconductor manufacturing apparatus of the present invention and a perspective cross-sectional view showing the structure of the upper electrode of the present invention.

In FIG. 2 (at, fbl), the same parts as in FIG.
', and a porous plate 11 is disposed above the gas outlet so as to cover the slit 4'.

A wafer 9 is disposed between the upper electrode 1' and the lower electrode 5, and a vacuum pump provided on the downward extension of the exhaust port 6 maintains the airtightness of the chamber 7 at a low pressure of, for example, about 1 Torr. A high frequency voltage is applied between the upper electrode 1 and the opposing lower electrode 5 by the generating section 8 to generate a high frequency discharge, and a gas such as 5iHn, NH3, etc. is introduced from the gas intake port 2 to generate plasma. Pass through the perforated plate 11 -ζ wide electrode part 3
The gas is discharged from the gas blowout slit 4' provided at 4'. Due to this discharge between the upper and lower electrode plates, the introduced gas, such as 5iHa or NH3, becomes a plasma state,
Therefore, radicals and ions are generated, causing a gas phase chemical reaction on the wafer 9, and forming a thin film. Here, the reason why a slit 4' having an elongated shape as shown in FIG. 2 (bl) is formed as a gas outlet will be explained.

In general, the ratio of the circumference to the area of a circle is α, and if the radius is r, then α −2πr/πr2 1 / r In other words, the smaller the diameter of the circle, the larger the ratio of the circumference. The smaller the diameter, the lower the electric field density, and therefore it becomes easier to suppress the concentration of the electric field. Therefore, in order to prevent the electric field concentration that causes such abnormal discharge, it is better to reduce the diameter of the hole as described above, but in reality, scaling of the hole diameter is necessary depending on the material of the electrode section, etc. has certain limits. Therefore, as an alternative method, the electric field concentration can be suppressed by forming the gas outlet into an elongated elliptical shape or a slit-like opening as in the embodiment of the present invention, thereby making it possible to prevent the above-mentioned abnormal discharge. . In addition, the perforated plate 11 provided on the slit 4' provided in the upper electrode of the present invention has a function of distributing gas.
Furthermore, by drilling a large number of circular holes in the perforated plate placed just before the slit 4' of the gas outlet, the slit 4'
By uniformly blowing out the gas from the wafer 9, it became possible to uniformly grow the thin film on the wafer 9 placed on the lower electrode 5.

As described above, when a slit-shaped gas outlet is used, the length of the edge can be made longer than that of a perfectly circular hole compared to the opening area, and electric field concentration can be avoided, so field lightning discharge can be prevented. It becomes difficult to wake up.

Furthermore, it is much easier to narrow the slit spacing as needed than to make small holes.

(7) Effects of the Invention When the semiconductor manufacturing apparatus of the present invention is used, the ratio of the outer edge circumference to the area of the opening of the gas outlet in the upper electrode part is large, so the electric field that causes abnormal discharge This makes it possible to prevent the concentration of oxides and to manufacture a semiconductor having a uniform film thickness.

Furthermore, when manufacturing the upper electrode, it becomes easier to form slits in the wide electrode portion, for example, and a manufacturing apparatus with higher precision can be obtained.

[Brief explanation of drawings]

FIGS. 1(a) to 1(C) show a cross-sectional view showing the overall structure of a conventional plasma CVD apparatus, a plan view seen from below an electrode part, and an open cross-sectional view, respectively. Second (al, (
FIG. 1 is a cross-sectional view showing the configuration of the semiconductor manufacturing apparatus of the present invention and a perspective cross-sectional view showing the structure of the electrode portion, which is a feature of the present invention. 1.1゛...upper electrode part, 2...gas intake port,
3, 3'... wide electrode section, 4'... pickpocket 7+.
, 5... Lower electrode part, 7... Chamber part, 8
...High frequency generation section, 9...Wafer, 10...
- Edge portion, 11... perforated plate. Patent applicant: Fujitsu Limited 135

Claims (4)

[Claims] (1) In a semiconductor manufacturing apparatus comprising an upper electrode and a lower electrode each having a gas outlet in a chamber, a wafer is placed on the lower electrode, and the chamber is filled with gas to cause plasma discharge. 1. A semiconductor manufacturing device comprising an opening having an appropriately shaped opening having a large ratio of circumference to area of a gas outlet. (2) The semiconductor manufacturing apparatus according to claim 1, further comprising a porous plate provided in the upper electrode to cover the gas outlet opening. (3) The semiconductor manufacturing apparatus according to claim 1, wherein the gas outlet of the upper electrode part has an elliptical shape. (4) The semiconductor manufacturing apparatus according to claim 1, wherein the gas outlet of the upper electrode part has a slotted shape.