JPS60200528A - Dry-etching equipment - Google Patents

Abstract

PURPOSE:To realize high-speed plasma-etching for a specimen surface by a method wherein electric force is generated with its lines roughly vertical to a magnetic flux generated by a column-shaped magnetron cathode in a reaction vessel for the creation of a magnetic field in parallel to the axis of the magnetron cathode in the vacancy between the magnetron cathode and a mount for said specimen. CONSTITUTION:An active halogenating gas is introduced into a reaction vessel 10 through a gas controller 13 and the vacuum within is kept at 10-10<-3>Torr. Application of high-frequency electric power across a column-shaped cathode 1 and the activation vessel 10 results in plasma produced around the column- shaped cathode 1. With the lines of electric force, generated between the column- shaped cathode 1 and the plasma, crossing the magnetic flux A in the magnetic field generated by a magnet 3 roughly at a right angle, electrons are driven into a magnetron movement. Under the conditions, a region is created near the cathode 1 wherein plasma density is very high, which allows low-tension of ions in great quantities to flow into the cathode 1. The consequence is a process wherein etching is greatly quickened of a specimen 4 positioned opposite to the side wall of the column-shaped cathode 1.

Description

[Detailed description of the invention] The present invention relates to a dry etching device used for etching.

In recent years, the miniaturization of semiconductor integrated circuits has been remarkable, and it has become difficult to process these fine patterns using conventional wet etching. Instead, anisotropic etching using dry etching has been used to process these integrated circuits. It has become an indispensable technology. There are several types of dry etching equipment of this type. For example, in a plasma etching method equipped with parallel plate electrodes, the sample is placed on the side facing the electrode to which high frequency waves are applied.

Aluminum, silicon oxide films, polysilicon, etc. can be etched by high frequency plasma of a reactive gas containing a halide such as fluorine or chlorine such as CF or CCl-4. In addition, by adjusting the electrode spacing, it is possible to perform etching while maintaining high etching rate selectivity between the photoresist and the underlying material, so it is commonly used in the etching process of semiconductor manufacturing. It's starting to look like this.

However, it has become clear that even with this plasma etching apparatus, various problems arise when attempting to perform microfabrication depending on the scale of mass production. For example, when etching a silicon oxide film with a mixed gas of CHF3 and 02, the etching rate is as low as 500 νmln.
When etching a 000X silicon oxide film, approximately 12 to 15 minutes of etching time is required, including additional etching. Trying to increase etching speed.

When the high frequency power is increased, the f-lasma potential increases and the rate of sputtering on the reaction vessel wall increases.
If the substrate surface is contaminated with heavy metals, which are the constituent materials of the reaction vessel, high-energy ion bombardment may adversely affect device characteristics. On the other hand, even in the case of aluminum etching and polysilicon etching, the etching speed at a practical level is at most 1000 Vmin, so when using this as a mass production device, the etching speed is 6 to 6 Vmin.
A so-called patch type device, which processes about 10 sheets at the same time, was superior in terms of cost and performance. However.

Recently, as the diameter of wafers has become larger, such as 125 mm or 150 mm, if we try to process them with the patch type processing equipment, we have no choice but to take up a large electrode area. , the equipment will have to become larger. Furthermore, the uniformity of the etching rate within one surface of the wafer tends to deteriorate, making it extremely difficult to microfabricate large-diameter wafers using conventional patch equipment.

On the other hand, for single-wafer processing equipment that sequentially processes each wafer, a parallel plate type high-speed etching equipment that achieves an etching speed of about 1 μMin has already been considered. In this case, the etching properties are poor, and the damage caused to the device by ion bombardment is particularly large.
sb is so hot. Due to such reasons, a high-speed magnetron etching method (which uses a magnetic field to perform high-speed etching in an area with a pressure 1 to 2 orders of magnitude lower than the previous method) has recently been developed as a device to achieve high-speed etching with less damage.
For example, Japanese Patent Application No. 56-151394) was devised. However, in this type of equipment, the plasma tends to concentrate only in the area where the electric field and the magnetic field are exactly perpendicular to each other, so the plasma is frequently moved by the drive of a magnet and the magnetic field is changed. It is necessary to make the etching rate distribution uniform. Therefore, there is a drawback that a large amount of cost is required for the drive mechanism of the magnet. Moreover, since a high high frequency voltage is applied to the side of the substrate to be etched, there remains the problem that ion bombardment is still large.

A first object of the present invention is to eliminate the above-mentioned conventional drawbacks and to improve the uniformity of the etching rate within the sample plane.

It is also an object of the present invention to provide a dry etching device that is capable of etching a sample at high speed.

The second object of the present invention is to make the voltage applied to the magnetron electrode sufficiently strong to increase the plasma density, and to
An object of the present invention is to provide a dry etching device that can perform high-speed etching without damaging a sample.

According to the present invention, there is provided a columnar magnetron cathode that generates lines of magnetic force in and out of the surface of the electrode near the surface of the electrode by a magnet provided inside the electrode, and a reaction vessel that surrounds the magnetron cathode. An anode formed by a wall or the like, a sample mounting table provided on the anode at a position opposite to the columnar surface of the magnetron cathode and grounded, and a high-frequency wave between the magnetron cathode and the anode. or means for applying a DC voltage to generate electric lines of force substantially perpendicular to the lines of magnetic force, and generating a magnetic field parallel to the axis of the columnar magnetron cathode in a space between the magnetron cathode and the sample mounting table; There is obtained a dry etching apparatus characterized in that the sample placed on the sample mounting table is soothed by an active gas plasma introduced into a reaction vessel.

Next, two embodiments of a dry etching apparatus according to the present invention will be described with reference to two drawings.

FIG. 1 is a side sectional view showing the structure of an embodiment according to the present invention. In this figure, 1 has a circular cross section.

The cathode is a rectangular or polygonal columnar magnetron cathode, and a sample mounting table 2 is provided at a position facing the columnar surface. Then, the sample 4 is placed on this sample mounting table 2. A magnet 3 is housed inside the columnar cathode 1 . This magnet 3 may be a permanent magnet or an electromagnet. Further, the number may be singular or plural, but when there is a plurality, the same poles are housed facing each other as shown in FIG. Cathode 1
is attached to the reaction vessel 10 via an insulator 5.

The structure is covered with a shielding material as necessary, and conventional techniques are used to prevent unnecessary electrical discharge from occurring at the base or the like. Power is supplied to the cathode 1 by a high frequency power source 6. The reaction vessel 10 has an exhaust pipe 11 and an exhaust valve 12
It is connected to the vacuum inlet via. The reaction gas is introduced into the reaction vessel through the gas controller 13. The electromagnetic coils 1-4 and 15 are provided in the space between the columnar cathode 1 and the sample mounting table 2 in order to generate a magnetic field substantially parallel to the axis of the column.

Now, to describe the operation of the apparatus configured as described above, one reaction vessel 10 is passed through an exhaust pipe 11 to +10-3
After evacuation to a vacuum of about 10-5 Torr.

Introduce a no-rodane active gas such as CF4 or BCl3 through the gas controller 3, and increase the degree of vacuum to 10 to 10-3.
Keep at Torr. In this state, by high frequency power supply I.

When high frequency power is applied between the columnar cathode 1 and the reaction vessel 10, plasma is generated around the columnar cathode 1.

Since the potential gradient generated in the ion sheath between the columnar cathode 1 and the plasma, that is, the lines of electric force, are almost perpendicular to the lines of magnetic force A of the magnetic field generated by the magnet 3, the electrons cause magnetromotion. It moves around the columnar cathode 1 while rotating. However, in this case, the electrons are transferred to the columnar cathode 1
1. This is because a spiral movement occurs around the negative electrode, and the state of hitting the cathode and being repelled is repeated. Column electrode 1
A region of extremely high plasma density occurs near the . When such high density plasma is generated.

Since the impedance of the plasma is reduced, a large ion current can be passed through the cathode at a low voltage.

For this reason, the sample 4 placed opposite the columnar surface of the columnar cathode 1
The etching speed is dramatically improved compared to conventional etching methods. Not only that, but the incident energy of ions entering the sample 4 can be lowered compared to conventional plasma etching equipment, and the concentrated plasma can be placed around the sample mounting table 2. No good.

It becomes possible to perform high-speed etching with less damage caused by ion injection or impurity contamination. At this time, the electromagnetic coils 14 and 15 provided on the outer periphery of the two reaction vessels 10 generate a magnetic field B. This magnetic field B serves to diffuse plasma concentrated near the cathode 1 toward the sample 4. The strength of this diffusion can be adjusted by adjusting the dimensions and arrangement of each member, and can also be finely adjusted by adjusting the current flowing through the electromagnetic coils 14 and 15.

As the sample mounting table 2 on which the sample 4 is placed, a plurality of ones similar to those shown in FIG. 1 can be arranged around the columnar electrode 1. When the part of the sample mounting table 2 other than the part covered by the sample 4 is large, the exposed part is covered with a cover plate made of quartz, organic matter, fluororesin, etc., and the inside of the columnar cathode 1 is water-cooled. It is preferable to cool it with or Iso. The cross-sectional shape of the columnar cathode 1 may be triangular, hexagonal, or octagonal depending on the number of sample mounting tables installed in opposition to each other, so that the planar columnar surface can face them. It is necessary to make it a polygon such as . Furthermore, making the opposing columnar surface a gently convex or concave surface also has a positive effect on improving the uniformity of etching. Naturally, if more samples are placed on one surface of the sample holder, a larger number of samples can be etched at the same time.

As is clear from the above description, according to the present invention, by appropriately selecting the size and distance of each member and finely adjusting the direction and size of the magnetic field B, it is possible to easily achieve uniform high density. Since plasma can be generated on the sample surface, uniform and high-speed etching is possible without damaging the sample. Furthermore, voltage, current and direct current can also be used as power sources.

It can be appropriately selected regardless of the high frequency, and has great effects in that ease of use and industrial usefulness are improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the structure of an embodiment of the dry etching apparatus according to the present invention, and FIG.
It is a block diagram which shows another example. In the figure, 1 is a magnetron cathode, 2 is a sample mounting table, 3 is a magnet, 4 is a sample, and 5
1 is an insulator, 6 is a high-frequency power source, 10 is a reaction vessel, 11 is an exhaust pipe, 12 is an exhaust valve, 13 is a +f controller, and 14 and 15 are electromagnetic coils. Figure 1] Figure 2 N 55 NN S Procedural Amendment March 25, 1985 1, Indication of Case 1982 Patent Application No. 56225 2, Title of Invention Dry Etching Apparatus 3, Person Making Amendment Case and Relationship between Patent applicant address: 5-8-15 Yotsuya, Fuchu-shi, Tokyo 183, Subject of amendment 6, Contents of amendment (1) From line 4 to line 7 of page 8 of the specification, ``In this figure, - -m- Sample mounting table 2 is provided.'' is corrected as follows. [In this figure, 1 is a columnar magnetron cathode whose cross section is circular, rectangular, or polygonal, such as triangular, square, hexagonal, or octagonal.
A sample mounting table 2 is provided. ``Yo,'' Ho J sings. (3) Amend the statement in the claims column as shown in the attached sheet. 2. Claim 1: A columnar Magne 1 to Heron cathode that generates lines of magnetic force in the vicinity of the surface of the electrode so as to enter and exit from the surface by a magnet provided inside the electrode, and the Magne 1 Heron cathode. an anode formed by the surrounding wall of the reaction vessel, a sample mounting table provided on the anode at a position facing the columnar surfaces of the magnetron cathodes and grounded, the magnetron cathode and the means for applying a high frequency or direct current voltage between the anode and the magnetic field line to generate electric lines of force substantially perpendicular to the magnetic field line; and a means for applying a magnetic field parallel to the axis of the columnar magnetron cathode to the sample mounting table. 1. A dry etching apparatus comprising means for generating etching in a space between the sample mounting table and etching a sample placed on a sample mounting table using active gas plasma introduced into a reaction vessel. (Attachment 1) The magnetron cathode is composed of a plurality of permanent magnets, each of which is connected with the same pole facing each other. xlL
No. 11 Ai 9 □ Dry etching device. Claims 1, 21, or 3, characterized in that the surface of the soil or magnetron cathode facing the sample mounting stage forms a flat surface 5 or a gently convex or concave curved surface. dry etching equipment. 1. A stand-up dry etching apparatus characterized in that a plurality of sample mounting stands are placed facing each other around a magnetron cathode. Dan. Claims No. 1, No. 21, No. 311, characterized in that a magnetic field parallel to the axis of the magnetron cathode is generated by an electromagnetic coil provided on the outer periphery of the reaction vessel.
741'' or the dry etching device described in the fifth vertebra. (Attachment 2)

Claims (1)

[Claims] 1. A columnar magnetron cathode that generates lines of magnetic force near the surface of the electrode so as to go in and out on the surface by a magnet provided inside the electrode; between an anode formed by a wall of a surrounding reaction vessel, etc., a sample mounting table provided on the anode at a position opposite to the columnar surface of the magnetron cathode and grounded, and the magnetron cathode and the anode; A means for generating electric lines of force substantially perpendicular to the lines of magnetic force by applying a high frequency or DC voltage, and a sample placed on a flat table on the axis of the columnar magnetron cathode are introduced into the reaction vessel. Dry etching equipment. 2. In the dry etching apparatus according to claim 1, the magnet provided inside the magnetron cathode is composed of a plurality of permanent magnets, each of which is connected with the same poles facing each other. A dry etching device characterized by: 3. In the dry etching apparatus according to claim 1 or 2, the surface of the magnetron cathode facing the sample mounting table is flat. Or a dry etching device characterized by forming a gently convex or concave curved surface. 4. The dry etching apparatus according to claim 1, 2, or 3, characterized in that a plurality of the sample mounting stands are placed facing around the magnetron cathode. Dry etching equipment. 5. Claims 1, 2, and 3. Or in the dry etching apparatus according to item 4,
Electromagnetic coil ++, Iff provided on the outer periphery of the reaction container
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A dry etching apparatus characterized in that it generates an i&6'+mJF 2''F-hElt field.