JPH10303178A - Dry etching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To etch an etched sample by arbitrarily setting the tilt angle of an etching side wall by applying a voltage upon a conductive masking material on the sample. SOLUTION: In a dry etching device, parallel planar electrodes composed of an anode 11 and a cathode 12 are provided in an etching process tank 10. The cathode 12 is connected to a high-frequency power source 13 and a matching device 14 and high-frequency discharge of a reactive gas introduced from a gas supplying system 15 can be caused between the anode 11 and cathode 12. In addition, an electrically connector 19 which connects the upper surface of an etched substrate 18 arranged on the cathode 12 to the cathode 12 is provided above the cathode 12 so as to make the potential at a mask pattern of a metallic material formed on the upper surface of the substrate 18 equal to that at the cathode 12. When this dry etching device is used, the potential at the mask pattern of the metallic material formed on the upper surface of the substrate 18 can be made equal to that at the cathode 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a dry etching apparatus.

[0002]

2. Description of the Related Art A dry etching technique is widely used in a semiconductor device manufacturing process as a fine processing technique excellent in mass productivity and processing dimension controllability. The conventional dry etching apparatus is described systematically and in detail in “Integrated Circuit Process Technology Series Semiconductor Dry Etching Technology (edited by Wei Tokuyama, Sangyo Tosho Co., Ltd.)”.

[0003]

The above conventional dry etching apparatus has the following problems.

The reason why mask pattern dimensions can be transferred to a substrate with high accuracy by dry etching such as reactive ion etching or reactive ion beam etching is that there is vertical anisotropy due to the effect of perpendicular incidence of ions. For this reason, the shape of the protrusion formed by the dry etching process may be such that the etched side wall is substantially vertical, or the trapezoidal shape having a narrow width on the side close to the mask due to the retreat phenomenon of the mask material, or the directivity of incident ions. Due to the spread of the property, the etching side wall was curved. In any case, it is extremely difficult to arbitrarily set the inclination angle of the etching side wall.

However, depending on the device to be manufactured, it may be desired to set the inclination angle of the etching side wall at the projection portion arbitrarily. For example, if a mesa stripe processing of a semiconductor laser manufactured on a semiconductor substrate is taken as an example, a current injection layer to be connected to a metal electrode in a later step is disposed in a portion of a mesa stripe portion processed by dry etching in contact with a mask. In addition, an active layer that generates light is disposed at a portion away from the mask in the direction of the substrate. In such a case, if the width of the current injection layer portion is smaller than or approximately equal to the width of the active layer portion, the resistance of the device increases, and the reliability regarding the life of the device decreases. In such a case, it is desirable that the cross-sectional shape of the protruding portion formed by dry etching be a wide inverted trapezoidal shape on the side close to the mask. However, dry etching at such an inclination angle was impossible with a conventional dry etching apparatus.

An object of the present invention is to provide a dry etching apparatus capable of performing etching by arbitrarily setting the inclination angle of an etching side wall.

[0007]

The object of the present invention is achieved by a dry etching apparatus provided with a mechanism for applying an arbitrary voltage to a conductive mask material on a sample to be etched. Further, the present invention is achieved by a dry etching apparatus provided with a mechanism for making the potential of a conductive mask material on a sample to be etched equal to that of an electrode plate on which the sample is placed.

First, the principle of two types of dry etching methods realized by the two types of dry etching apparatuses of the present invention will be described in detail with reference to FIG.

A feature of the first dry etching apparatus is that a conductive material such as a metal is used for a mask material used for dry etching, and an arbitrary potential is applied to the conductive material to arbitrarily bend the direction of incident ions to form an etching side wall. An object of the present invention is to realize an etching process that can freely set an angle.

As shown in FIG. 1A, when a negative potential is applied to a mask 2 on a substrate 1 to be etched by using a DC power supply 3, the incident angle of the incident positive ions 4 is increased in the vicinity of the mask 2. 2 has a directivity such that it goes under the mask 2, so that an inverted trapezoidal cross-sectional shape is obtained in which the width is large immediately below the mask 2 and the width decreases as the distance from the mask 2 increases. On the other hand, as shown in FIG. 1B, when a positive potential is applied to the mask by using the DC power supply 3, the incident angle of the incident positive ions 4 becomes less directivity in the direction away from the mask 2 near the mask 2. Therefore, a trapezoidal cross-sectional shape is obtained in which the width is narrow immediately below the mask 2 and the width increases as the distance from the mask 2 increases. Therefore, if the potential value applied to the mask 2 is arbitrarily selected, the inclination angle of the etching side wall can be arbitrarily changed.

A feature of the second dry etching apparatus is that a conductive material such as a metal is used for a mask material used for dry etching, and the mask is electrically connected to an electrode plate on which a sample is to be placed, so as to have an equipotential. Accordingly, it is possible to realize an etching process in which the direction of incident ions is bent and the angle of the etching side wall can be set to be non-perpendicular.

FIG. 1C is a schematic view showing a state in which a substrate 1 to be etched on which a stripe mask pattern 6 of a metal material is formed in advance on a cathode electrode 5 of a reactive ion etching apparatus having a parallel plate type electrode structure. It is.
Here, the stripe mask pattern 6 made of a metal material is formed in a comb shape, and a part thereof is connected to the cathode electrode 5 by using a metal wiring 7 provided in the device so that the cathode mask 5 has the same potential. It is.

When an etching gas is introduced between the parallel plate type electrodes and high frequency power is applied to the anode electrode 8 and the cathode electrode 5 using a high frequency power supply 9 to induce plasma, positively charged reactive ions are generated by the cathode substrate. 5, the etching of the substrate to be etched 1 proceeds. At this time, since the stripe mask pattern 6 of the metal material formed on the substrate 1 to be etched has the same potential as the cathode electrode 5, the traveling direction of the incident reactive ions is bent near the stripe mask pattern 6 of the metal material. As a result, since the metal goes around the lower side of the stripe mask pattern 6 made of a metal material, dry etching of an inverted trapezoidal shape is realized. When this method is used, in order to arbitrarily set the inclination angle of the etching side wall, for example, as a mask material, a multilayer mask of a dielectric film and a metal film in contact with the substrate to be etched is used, and the thickness of the dielectric film is changed. Alternatively, the thickness of the metal part of the mask may be changed. This is because the direction of the incident ions changes according to the thickness of the dielectric film or the thickness of the metal portion of the mask.

The two types of dry etching apparatus of the present invention can realize the above two types of dry etching methods, and thus operate as a dry etching apparatus for performing etching by arbitrarily setting the inclination angle of the etching side wall. is there.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 First, a first embodiment of the present invention will be described in detail with reference to FIG. FIG. 2 shows an example of a dry etching apparatus according to the present invention.
1 and a cathode electrode 12. A high-frequency power supply 13 and a matching device 14 are connected to the cathode electrode 12 so that a high-frequency discharge of a reactive gas introduced from a gas supply system 15 into the parallel plate electrode can be caused. The interior of the etching tank 10 can be evacuated by a turbo molecular pump 16 and a rotary pump 17. In addition, the cathode electrode 1
The mask pattern (not shown) of a metal material formed on the upper surface of the substrate 18 to be etched
An electrical connector 19 for connecting the upper surface of the substrate 18 to be etched and the cathode electrode 12 to make the potential equal to 2 is provided on the cathode electrode 12. By using this dry etching apparatus, the mask pattern of the metal material formed on the upper surface of the substrate to be etched 18 can be made to have the same potential as that of the cathode electrode 12, so that the dry etching in which the cross-sectional shape after the etching becomes an inverted trapezoidal shape is performed. It is possible. It is needless to say that the inclination angle of the etching side wall can be changed by changing the thickness of the mask pattern of the metal material formed on the upper surface of the substrate 18 to be etched.

In this embodiment, the case where the mechanism of the present invention is provided in a reactive ion etching apparatus having a parallel plate type electrode structure has been described. However, a magnetron type reactive ion etching apparatus and a microwave plasma etching It goes without saying that the same effect can be obtained by providing another dry etching apparatus such as an apparatus with a connection mechanism for electrically connecting the cathode electrode and the mask on the upper surface of the substrate to be etched.

(Embodiment 2) Next, a second embodiment of the present invention will be described in detail with reference to FIG. FIG. 3 shows an example of the dry etching apparatus of the present invention. This apparatus introduces a microwave of 2.45 Ghz from the waveguide 20 into the plasma generation chamber 21 and simultaneously generates a static magnetic field of 875 Gauss by the magnetic field coil 22 to generate electrons. A mechanism is provided for generating highly ionized plasma of the reactive gas introduced from the gas supply system 23 by causing cyclotron resonance (hereinafter abbreviated as ECR). The reactive ions are extracted from the plasma generation chamber 21 by the voltage applied to the ion extraction grid 24 and enter the substrate 27 to be etched on the sample stage 26 in the etching chamber 25. Further, this apparatus is provided with a cryopump 28 for keeping the inside of the etching at a high vacuum.
Further, a DC power supply 29 for applying an arbitrary voltage to the mask pattern of the metal material formed on the upper surface of the substrate 27 to be etched is provided.

By using this dry etching apparatus, an arbitrary voltage can be applied to the mask pattern of the metal material formed on the upper surface of the substrate 27 to be etched. It is possible. In this embodiment, the case where the mechanism of the present invention is provided in the ECR type reactive ion beam etching apparatus is described. However, a parallel plate type reactive ion etching apparatus, a magnetron type reactive ion etching apparatus, Needless to say, the same effect can be obtained by providing another dry etching apparatus such as a microwave plasma etching apparatus or a cylindrical plasma etching apparatus with a power supply for applying an arbitrary voltage to the mask on the upper surface of the substrate to be etched. .

[0019]

According to the dry etching apparatus of the present invention, it is possible to perform an etching process in which the inclination angle of the etching side wall is arbitrarily set, and the degree of freedom in element design is greatly improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the principle of the present invention.

FIG. 2 is an explanatory view showing a schematic structure of a dry etching apparatus according to one embodiment of the present invention.

FIG. 3 is an explanatory view showing a schematic structure of a dry etching apparatus according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate to be etched, 2 ... Mask, 3 ... DC power supply, 4
... Incoming positive ions, 5 ... Cathode electrode, 6 ... Stripe mask pattern of metal material, 7 ... Metal wiring, 8 ... Anode electrode, 9
... high frequency power supply, 10 ... etching tank, 11 ... anode electrode, 12 ... cathode electrode, 13 ... high frequency power supply, 14 ... matching device, 15 ... gas supply system, 16 ... turbo molecular pump, 17
... Rotary pump, 18 ... Substrate to be etched, 19 ...
Electrical connector, 20: waveguide, 21: plasma generation chamber, 2
2: magnetic field coil, 23: gas supply system, 24: ion extraction grid, 25: etching chamber, 26: sample table, 27
... substrate to be etched, 28 ... cryopump, 29 ... DC power supply.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuhisa Uomi 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (2)

[Claims] 1. A dry etching apparatus comprising a mechanism for applying an arbitrary voltage to a conductive mask material on a sample to be etched. 2. A dry etching apparatus comprising: a mechanism for setting the potential of a conductive mask material on a sample to be etched to the same potential as an electrode plate on which the sample is placed.