JPH05234947A - Microwave plasma etching device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of sputtering of a metallic body which transmits activated particles but shieds microwaves without making a device larger in size by forming a reactive gas transmitting body by coating at least the front and rear surfaces of a porous or netty metallic plate with a material which hardly reacts to a reactive gas. CONSTITUTION:The title etching device is provided with a microwave generating section 39, plasma generating chamber 33 into which microwaves generated by the section 39 and a reactive gas are introduced, and etching chamber 34 into which the reactive gas from the chamber 33 is introduced through a porous or netty transmitting body 31. In such microwave plasma etching device 30, the transmitting body 31 is formed by coating at least the front and rear surfaces of a porous or netty metallic plate with a material which hardly react to the reactive gas. For example, the body 31 is formed by coating the entire surface of an Al netty plate 40 having a thickness of several millimeters with an electrically insulating member 41 of a fluororesin, quartz, alumina, etc.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave plasma etching apparatus, and more particularly to a downflow type apparatus.

[0002]

2. Description of the Related Art Etching technology for a single crystal or polycrystalline silicon (Si) film and a Si ₃ N ₄ film by CF 4 gas plasma has already been applied to large scale integrated circuits (LSI).
Have become popular as a manufacturing technology for fine structures such as. In this etching technique, a so-called down-flow method is often used in which a processing chamber is provided immediately below the plasma generation chamber and a reaction gas converted into activated particles flows downward in order to effectively act the activated particles generated by microwave excitation. ing. In this method, a metal mesh plate, for example, is provided at the boundary between the plasma generation chamber and the processing chamber in order to equalize the flow of the reaction gas turned into active particles and to block the microwave.
However, since the mesh plate comes into contact with plasma, it is subjected to sputter processing, which causes a problem of contaminating the substrate to be processed. In order to solve this problem, the technique disclosed in Japanese Patent Laid-Open No. 61-30036 has been conventionally known. That is, as shown in FIG. 3, this technique has a microwave introduction means (13) provided with a waveguide (12) having a microwave transmission window (11) formed at the top thereof, and introduces a reaction gas. The plasma generation chamber (15) to which the tube (14) is connected, the plasma cutoff chamber (17) that communicates with the lower part of the plasma generation chamber (15) and has a magnet coil (16) around the outside, and this plasma The work chamber (20) is provided with a metal mesh (18) made of aluminum or the like at the boundary with the shut-off chamber (17) and further connected to an exhaust pipe (19). The inside of the processing chamber (20) is provided with a workpiece support means (23) for supporting the substrate (22) to be processed.

In the above apparatus, the plasma generating chamber (15), the plasma shut-off chamber (17) and the processing chamber (20) are kept at a gas pressure of about 10 ^-4 Torr and are excited by the plasma (24) to be generated. Active particles such as fluorine ions and fluorine radicals are processed in the processing room.
(20) Fly inside. When the active particles pass through the metal mesh (18) in this flight, microwaves are blocked by the metal mesh (18). In addition, since the plasma shut-off chamber (17) is provided between the metal mesh (18) and the plasma generation chamber (15), the metal mesh (18) is not sputtered and the substrate to be processed (22) is prevented from being contaminated. To be done.

[0004]

In the above structure, the plasma blocking chamber provided to prevent the metal mesh (18) from spattering is
In order to improve the prevention effect, it is desirable to lengthen the interval between the plasma generation chamber (15) and the processing chamber (20), but if the length is increased, the active state of the active particles will be weakened or lost, so there is a limit. If the etching rate is prioritized, spatter is generated and the substrate to be processed (22) is contaminated. In addition, the provision of such a plasma blocking chamber (17) causes a problem that the device becomes large.

The present invention has been made to solve such a problem, and prevents the generation of spatter of a metal body that allows active particles to pass therethrough and blocks microwaves without increasing the size of the apparatus. It was done. [Constitution of Invention]

[0006]

[Means and Actions for Solving the Problems] Microwave generating part, plasma generating chamber into which microwave and reactive gas generated from the microwave generating part are introduced, and reactive gas from the plasma generating chamber In a microwave plasma etching apparatus provided with an etching chamber introduced through a porous plate-shaped or mesh plate passage body, wherein the passage body has at least the front and back surfaces of the metal porous plate or mesh plate with the reactivity. It is characterized in that it is formed by coating with a material that does not easily react with gas, and unnecessary spatter can be prevented without affecting the etching rate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments. FIG. 1 shows a so-called downflow type microwave plasma etching apparatus according to an embodiment of the present invention. That is, it has a pressure-tight airtight container (30), and this container is formed in a quartz window (32) for allowing microwaves to pass therethrough by a substantially horizontally supported air-permeable through member (31). The plasma generating chamber (33) is divided into an upper side and an etching processing chamber (34) below. Further, on the side of the plasma generation chamber (33), CF4 is placed in the plasma generation chamber (33).
A gas supply pipe (35) for introducing a reaction gas such as is connected. Further, a processing table (36) is provided inside the etching processing chamber (34), and an exhaust pipe (37) connected to a pressure reducing means (not shown) such as a vacuum pump is connected to a side portion thereof. . On the other hand, a waveguide is installed above the plasma generation chamber (33).
(38) is attached to the microwave generator (39) and the microwave is introduced into the airtight container (30) through the quartz window (32). As shown in FIG. 2, the nozzle (31) has a three-layer structure in which the entire mesh plate (40) made of aluminum having a thickness of several mm is covered with an electrically insulating member (41) to a thickness of about a little less than 0.5 mm. Thus, a passage portion having a diameter of about 3 to 4 mm and a passage portion of the same degree is formed. The electrically insulating member (41) is selected from those having corrosion resistance such as fluorine resin, quartz and alumina.

Next, the above configuration will be described. A substrate (42) on which a polycrystalline silicon layer is formed and which is coated with a photoresist film for forming an etching pattern on the layer is mounted on a processing table (36), and an airtight container (30) is placed. After keeping airtight and high vacuum, gas supply pipe (35)
The reaction gas is supplied from the inside of the airtight container (30) while maintaining the exhaust gas from the exhaust pipe (37) at a gas pressure of about 10 ⁻³ Pascal. Install the substrate (42) in the plasma generation chamber (3
It is set at a location near 3). Under such a condition, a microwave of a predetermined wavelength guided by the waveguide (38) is introduced into the plasma generation chamber (33) through the quartz window (32), and the plasma generation chamber
The reaction gas in (33) is ionized to generate active particles.
These active particles are distributed almost evenly into the etching chamber (34) from the passage body (31) together with the reaction gas which is not activated, and are dry-etched along the etching pattern. Here, since the surface layer portion of the passage body (31) is the electrically insulating member (41), it does not react with the reactive gas and the spattering phenomenon due to the active particles does not occur, and the core of the passage body (31) is generated. Since the part is metal, microwaves are blocked.

Although the core of the passage body (31) is a mesh plate in the above embodiment, it is a perforated plate having a plurality of holes formed at a predetermined pitch, and only the front and back surfaces are covered with an electrically insulating member to form a hole. The wall may be left as an exposed passage body.

[0010]

EFFECTS OF THE INVENTION The coating of the electrically insulating member almost eliminates the reaction and spattering phenomenon in the passing body, the active action of the active particles is not lost, and the microwave blocking action is not lost, so that the etching rate is maximized. In addition, it is possible to prevent the contamination of the object to be processed and contribute to higher density processing.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

2 is a partial cross-sectional view of FIG.

FIG. 3 is a configuration diagram showing a conventional example.

[Explanation of symbols]

(15)… Plasma generation chamber, (34)… Etching processing chamber, (31)
... Passing body, (39) ... Microwave generating part, (40) ... mesh plate, (41) ...
Electrically insulating material.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Nanzan 8 Shinsita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock company Toshiba Yokohama office

Claims (1)

[Claims] 1. A microwave generation part, a plasma generation chamber into which the microwave and reactive gas generated from this microwave generation part are introduced, and a reactive gas from this plasma generation chamber is a porous plate or a mesh. In a microwave plasma etching apparatus provided with an etching processing chamber introduced through a plate passing body, the passing body is a material that is hard to react with the reactive gas on at least the front and back surfaces of a metallic porous plate or mesh plate. A microwave plasma etching apparatus characterized by being formed by coating with.