JPH02184028A - Dry etching device - Google Patents

Abstract

PURPOSE:To increase the number of atoms which are irradiated to a sample per unit time and unit area by providing an electron radiator, which forms cluster ions by making electrons collide against a cluster, and a cluster ion accelerating electrode, which accelerates the cluster ions and irradiates the sample with the cluster ions so as to etch the sample, at the inlet part of a sample chamber which is linked up with a cluster generation chamber. CONSTITUTION:A filament 24 and a mesh-shaped electron accelerating anode 27, whose potential is set higher than it, are arranged in an electron radiator 23, and flowing-in clusters and electrons, which are generated by a filament 24 and are accelerated by the electron accelerating anode 27, collide with each other, and the clusters are ionized. Next, these cluster ions are accelerated by a cluster ion accelerating electrode 28, which is set to the potential lower than the filament by a second DC power source 31, and is formed in a beam and the beam is applied vertically to a sample 12 within a sample chamber 7. Hereby, the sample 12 is etched chemically or physically by etching species contained in cluster ions. The products which are generated by etching reaction are always exhausted from an exhaust port 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a dry etching apparatus for etching samples such as semiconductor substrates.

[Prior Art] Fig. 3 is a configuration diagram showing an example of an ion beam device which is a conventional dry etching device, in which il+ is a plasma chamber, and (2) is a thermionic cathode provided in the plasma chamber (1). , (3) is a heating power source for heating the thermionic cathode (2), (4) is a discharge power source connected to the thermionic cathode (2), heating power source (3), and plasma chamber (11), (5) is the reaction gas introduction tube installed in the plasma chamber (11), (6)
is a magnetic coil installed around the plasma chamber (1) to increase discharge efficiency.

(7) is a sample chamber connected to the plasma chamber (1),
81, (411 are the first and second ion extraction electrodes provided in the population part of the sample chamber (7), +101 is formed in the sample chamber (7) and connected to the plasma chamber (1) and the sample chamber (7)
+Ill is the first and second ion extraction electrode (8).

A sample stage (9) is placed opposite to the sample stage (12), and a sample is placed on the sample stage (11).

In the ion beam etching apparatus configured as described above, a reaction gas is flowed into the plasma chamber (1) from the gas introduction pipe (5), and the thermionic cathode ( 2) and the wall of the plasma chamber (1), which is placed at a higher potential than the thermionic cathode (2) by the discharge power source (4), a direct current discharge occurs, and plasma is generated in the plasma chamber (1). is generated.

Next, the plasma generated in the plasma chamber (1) is transferred to the mesh-shaped 1i5 and the second ion extraction electrode +81,
191 to form a shirt-shaped ion beam. This ion shower is guided to a sample chamber (7) adjacent to the plasma chamber (1), and a sample (12) placed on a sample stage (+tlf:) is appropriately irradiated with ions to perform etching.

[Problems to be Solved by the Invention] In the conventional ion beam etching apparatus, in order to extract ions from the plasma chamber (1) to the sample chamber (7), a first 1000 to 2000 between the ion extraction electrode (8) and the second ion extraction electrode (9) set to the same potential as the sample chamber (7).
A DC voltage of V is applied, and ions accelerated under such a high voltage have large kinetic energy, and when they reach the surface of the sample (12), the crystallinity of the etched surface changes by 7.
There was a problem in that zero scratches were caused, forming a defective layer and significantly deteriorating the performance of the sample.

Furthermore, if the voltage applied to the second ion extraction electrode (9) is set to a moderately low voltage of several hundred volts, the formation of a defective layer in sample] 12) is reduced, but the etching efficiency is also significantly reduced at 10 o'clock. There was a problem with this.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a dry etching apparatus that can obtain samples with little damage and can perform etching at high speed.

[Means for Solving the Problems J] A dry etching apparatus according to the present invention includes a chamber that includes a cluster generation chamber that generates clusters from a reaction gas;
A sample chamber is connected to this cluster generation chamber and contains a sample to be etched. At the entrance of the sample chamber, there is an electron emitter that collides electrons with the clusters to form cluster ions, and an electron emitter that collides with the clusters to form cluster ions. The device is equipped with a cluster ion accelerating electrode that accelerates and irradiates the sample to etch the sample.

[Operation] The dry etching device of the present invention utilizes cluster ions as etching agents, so that the kinetic energy per unit atom is small and the number of atoms irradiated on a sample per unit time and unit area can be increased. It becomes possible.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a dry etching apparatus according to a first embodiment of the present invention, and the same or corresponding parts as in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted.

In the figure, Izo) is a cluster generation chamber in which clusters are generated;
+231 is an electron emitter connected to the cluster generation chamber (20), (24)
is a filament connected to an AC power source (25), (27
) is connected to the first DC power supply (26) and the filament (
24) is a mesh-like electron accelerating anode whose potential is set higher than that of the filament (24), and +281 is a cluster ion accelerating electrode which is connected to the second DC power supply (31) and whose potential is set lower than that of the filament (24).

In the dry etching apparatus configured as described above, the sample chamber (7), the electron emitter I4 (23) i5, and the cluster generation chamber (20) form an integrated vacuum chamber, and the exhaust port (I
Exhaust is performed from O), and 10-” ~lOmTnrr
A vacuum is maintained. The etching gas is lowered to a temperature close to its boiling point in the gas cooling chamber (21), and then the etching gas is cooled to the nozzle 12.
2) to 11 are introduced into the cluster generation chamber (20) which is kept empty. At this time, the gas expands adiabatically and liquefies,
A mass or cluster of several tens to several atoms or molecules is formed. This cluster is diffused within the electronic QJ device (23).

Inside this electron emission n f231 is a filament (24)
and a mesh-like electron accelerating anode (21) set at a higher potential than this, the inflowing clusters and the electron accelerating anode (27) generated by the filament (24) are accelerated. The cluster ions are ionized by colliding with the generated electrons (called Ishitoshi cluster ions).Next, these cluster ions are ionized by a second DC power source (
31), the cluster ion accelerating electrode (28) is set at a lower potential than the filament (24), and the cluster ion accelerating electrode (28) forms a beam which is irradiated perpendicularly to the surface of the sample (12) in the sample chamber (7).

As a result, the sample (12) is chemically or physically etched by the etching species contained in the cluster ions. The products generated in the etching reaction are removed from the exhaust port (lO).
is constantly exhausted.

In addition, in the embodiment mentioned above, a cooling device is provided for cooling the etching gas in the gas cooling chamber (21), but this is for the case where the etching gas is a gas at room temperature, such as C20, and the etching gas is a liquid gas at room temperature. For example, in the case of CC24, etc., a cooling device is not required.

FIG. 2 is a block diagram showing another embodiment of the present invention, in which a light source (29) is used to irradiate the surface of a sample (12) with light in order to promote the etching reaction with a class-quenching beam.
and a light irradiation window (30) are attached. In this case, the operation of the first embodiment of the present invention is performed except that the light emitted from the light source (29) passes through the light irradiation window (30) and is irradiated onto the surface of the sample (12). is the same as

Table 1 shows capacitors when polysilicon serving as a MOS capacitor electrode is etched with CCβ4 gas as an example in which the dry etching apparatuses of the conventional example, the first embodiment, and the second practical example are used for manufacturing semiconductor devices. This is a measurement of the breakdown voltage defect rate.

As can be seen from these results, if the dry etching apparatus of the present invention is used in semiconductor manufacturing, high-performance, highly reliable semiconductor devices with low etching damage can be produced.

Manufactured in less time.

[Effects of the Invention] As explained above, since the dry etching apparatus of the present invention uses cluster ions as etching species, the kinetic energy per unit atom is small, and the kinetic energy per unit time and unit area is small. The number of atoms irradiated onto the sample increases, making it possible to minimize damage to the sample during etching and increasing the etching speed.
- It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a dry etching apparatus according to a first embodiment of the present invention, FIG. 2 is a block diagram showing a second embodiment of the present invention, and FIG. 3 is an example of a conventional dry etching apparatus. FIG. In the figure, (7) is the sample chamber, port 2) is the sample, and (20)
is the Krasuf generation chamber, (23) is the electron emitter, f281
is a cluster ion accelerating electrode. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Teru So Ga Do Figure 1 Trap Figure 2

Claims (1)

[Claims] In a dry etching device that chemically or physically etches a sample in a chamber with a reactive gas,
The chamber includes a cluster generation chamber that generates clusters from the reaction gas, and a sample chamber that is connected to the cluster generation chamber and into which a sample to be etched is placed, and an entrance portion of the sample chamber has a cluster generation chamber that generates clusters from the reaction gas. A dry etching apparatus comprising: an electron emitter that collides electrons with clusters to form cluster ions; and a cluster ion accelerating electrode that accelerates the cluster ions and irradiates them onto the sample to etch the sample. .