JPH0774466B2 - Etching device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an etching apparatus for dry-etching a sample contained in a vacuum container, and particularly to an etching apparatus capable of switching between ion beam etching and ion etching. Regarding

[Conventional technology]

FIG. 4 is a schematic diagram showing an example of a conventional etching apparatus. This equipment is an ion beam etching equipment,
A disk 18 that is rotated at a high speed by a driving device 20 is provided in the vacuum container 16, and a plurality of samples 22 are mounted on the peripheral portion of the disk 18. Then, the sample 22 is irradiated with the ion beam 14 from the ion source 2 for etching.

More specifically, the ion source 2 is an ECR type ion source, and includes a plasma chamber 4 for producing plasma, a magnetic field coil 6 for confining the plasma, and an ion beam 14 from the plasma chamber 4.
The plasma chamber 4 is equipped with an extraction electrode system 8 for drawing out the plasma.
Of the microwave power, and a gas (for example, a reactive gas) is supplied from the gas source 11 through the mass flow controller 12 for adjusting the flow rate, whereby the gas and the microwave supplied to the ion source 2 are supplied. A plasma is generated using the wave power, and an ion beam 14 containing, for example, reactive ions is extracted from the plasma.

On the path of the ion beam 14 from the ion source 2, a shutter 24 that opens and closes the ion beam 14 is provided. 26 is the drive device. 28 and 30
Is an amplifier for measuring the beam current of the ion beam 14 with which the shutter 24 or the disk 18 is irradiated. The disc 18 and the shutter 24 are insulated from the ground.

The sample 22 is, for example, as shown in FIG. 5, in which the surface of a substrate 221 made of, for example, silicon is covered with an etching layer 222 made of, for example, silicon oxide, and further covered with a resist 223 having a desired pattern. Is.

When etching the sample 22, for example, a shutter
After adjusting the beam current of the ion beam 14 to a predetermined value using 24 or the like, the shutter 24 is opened and the sample 22 on the disk 18 which is rotating at high speed is irradiated with the ion beam 14. As a result, each sample 22 has an etching layer 2 according to the pattern of the resist 223, as shown by the broken line in FIG.
22 is etched.

[Problems to be solved by the invention]

When the sample 22 is etched using the ion beam 14 as described above, the ion beam 14 is used before the etching.
Although the damaged portion of the sample 22 due to etching (for example, a portion such as a lattice defect) is scraped off by the etching in the next step even if the energy of is high, it does not pose a problem.
The sample 22 remains to some extent, which causes various problems in manufacturing a device or the like using the sample 22.

On the other hand, it is considered that the energy of the ion beam 14 is reduced as much as possible near the end stage of etching to suppress the damage of the sample 22 as much as possible. The current inevitably drops significantly, which lowers the etching rate and causes new problems in terms of productivity.

Therefore, an object of the present invention is to provide an etching apparatus capable of suppressing damage to a sample as much as possible, preventing a decrease in etching rate, and simplifying the apparatus configuration.

[Means for solving problems]

The etching apparatus of the present invention is an apparatus for dry-etching a sample on a rotary disk housed in a vacuum container, and an ECR type ion source for irradiating an ion beam on the sample on the disk, and this ion source. A shutter provided between the disc and the disc that opens and closes the ion beam extracted from the ion source and forms a plasma generation space between the disc and the surface containing the sample when the shutter is closed. A gas source for supplying gas, a microwave oscillator for generating microwave power, gas switching means for supplying gas from the gas source by switching to the ion source and the plasma generation space, A microwave switching means for switching and supplying microwave power from a microwave oscillator to the ion source and the plasma generation space; By opening and closing the shutter and switching the gas switching means and the microwave switching means, an ion beam is extracted from the ion source by using the gas and microwave power supplied thereto, and the ion beam is extracted as a sample on the disk. Irradiation and generation of plasma in the plasma generation space using the gas and microwave power supplied thereto are switched to be performed.

[Action]

By switching the gas switching means and the microwave switching means to the ion source side, it is possible to irradiate the sample on the disk with the ion beam from the ion source, thereby providing a large etching rate for the sample and excellent anisotropy. Ion beam etching is performed. On the other hand, by closing the shutter and switching the gas switching means and the microwave switching means to the side of the plasma generation space, it is possible to generate a microwave discharge in the vicinity of the sample and generate plasma, thereby damaging the sample. Ion etching is performed at a high etching rate while suppressing it as much as possible. Therefore, in this etching apparatus, for example, it is possible to switch between ion beam etching in the pre-etching stage and ion etching in the post-etching stage, thereby minimizing damage to the sample and preventing a decrease in the etching rate. You can

〔Example〕

FIG. 1 is a schematic diagram showing an etching apparatus according to an embodiment of the present invention. The same or corresponding parts as those in FIG. 4 are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, by closing the shutter 24, a plasma generation space is formed between the shutter 24 and the surface of the disk 18 including the sample 22.

Further, a gas branch switch 36 or the like is provided as a gas switching means, and the gas supplied from the gas source 11 via the mass flow controller 12 as described above is supplied to the plasma of the ion source 2 using the gas branch switch 36. The chamber 4 and the plasma generation space are switched and supplied.
37a and 37b are pipes for that purpose.

Further, a circulator 38 and the like are provided as microwave switching means, and the microwave power output from the microwave oscillator 10 as described above is supplied to the plasma chamber 4 of the ion source 2 and the plasma generation space by using the circulator 38. I am switching to and to supply. Reference numerals 39a and 39b are waveguides therefor.

Further, in this embodiment, a control device 48 for controlling the switching of the gas branch switch 36 and the circulator 38 and various controls of other devices is provided.

Therefore, by opening the shutter 24 and switching the gas branch switch 36 and the circulator 38 to the ion source 2 side, the ion beam 14 is extracted from the ion source 2 by using the gas and microwave power supplied thereto. Ion beam etching can be performed by irradiating the sample 22 on the disk 18. On the contrary, by closing the shutter 24 and switching the gas branch switch 36 and the circulator 38 to the plasma generation space side,
In the plasma generation space between the shutter 18 and the shutter 24, the gas supplied thereto and the microwave power are used to generate the plasma 50 by the microwave discharge, so that the sample 22 can be ion-etched.

Next, an example of the overall operation of the above device will be described. For example, the sample 22 is etched with the ion beam 14 from the beginning to a predetermined etching stage, for example, near the end stage where damage to the sample 22 becomes a problem. That is, first, for example, by using the rough evacuation device 32 and the high vacuum evacuation device 34, the inside of the vacuum container 16 is set to a predetermined vacuum degree (for example, 10 ^-4 to 10
^-5 Torr) and gas branch switch 36
With the circulator 38 on the side of the ion source 2, the shutter 24 is closed, the ion beam 14 of a desired size is extracted from the ion source 2, and the beam current is measured via the amplifier 28 and the like to obtain the desired one. To do. After that, the shutter 24 is opened, and the sample 22 on the disk 18 rotating at high speed is irradiated with the ion beam 14 to etch each sample 22.

In that case, the problem of damage to sample 22 would be the subsequent plasma 50.
Since it can be solved by the ion etching by using, it is possible to increase the energy of the ion beam 14 for etching. Therefore, it is possible to perform etching with a large etching rate and excellent anisotropy because it is ion beam etching. .

Next, when the etching reaches a predetermined stage, for example, near the above-mentioned end stage, the ion beam 14 is stopped, and instead, the plasma 50 is generated as described above to generate the sample 22.
To etch.

In that case, the detection that the etching has reached the predetermined stage may be made by a known means such as controlling the etching time.
Detecting body 42 and detecting device 44 mounted instead of one sample 22
And an etching amount detecting device including a counting device 46. The detector 42 is, for example, as shown in FIG.
Regions to be etched, that is, a layer 422 made of the same material as the etching layer 222 and a thin film layer made of a different material from the layer 422.
Substrate 421 and 423 are alternately laminated. Although the interval T between the thin film layers 423 may be arbitrary,
It is preferable to set the intervals at equal intervals because the later-described calculation and the like will be easier. The detection device 44 is, for example, an emission spectrometer or a mass spectrometer, and detects that the thin film layer 423 in the detection body 42 has been etched by emission spectroscopy or mass spectrometry, and then detects, for example, a pulse shape each time. The detection signal S of is output. One example is shown in FIG. The counting device 46 includes, for example, a counter, and counts the number of detection signals S from the detection device 44.

The detection body 42 on the disk 18 is etched by the ion beam 14 (or by the plasma 50) together with the sample 22 at substantially the same etching rate as the sample 22, and the detection signal S as described above is obtained. In this case, since the interval T between the thin film layers 423 is predetermined, the number of the detection signals S corresponds to the etching amount (etching thickness) of the detection body 42, and thus the etching amount of the sample 22. Therefore, sample 22
The etching amount at any stage can be accurately detected by (number of detection signals S) × (interval T).

Therefore, for example, using the etching amount detection device as described above, it is detected that the etching of the sample 22 has progressed to the vicinity of the end stage (for example, one or two before in the interval T of the final etching amount). The signal is provided to the controller 48. In response, the controller 48 switches between ion beam etching with the ion beam 14 and ion etching with the plasma 50.

That is, the shutter 24 is closed, and the gas branch switch 36 and the circulator 38 are switched to supply the gas from the gas source 11 and the microwave power from the microwave oscillator 10 to the sample 22.
Switch to the side. In that case, the degree of vacuum in the vacuum container 16 is
For example, by stopping the high vacuum reference vacuum evacuation device 34 or operating only the rough reference vacuum evacuation device 32, a vacuum degree convenient for generating the plasma 50 (for example, 10 ^-1 to 10 ^-2).
Torr level).

This allows the disc 18 and shutter to rotate at high speed.
The high-density plasma 50 is generated in the plasma generation space of 24 volumes, and the plurality of samples 22 and the detection body 42 mounted on the disk 18 pass through the region of the plasma 50, and the ions in the plasma 50 at that time. Is etched by. In this case, since the etching rate is large and the energy of the ions is small (for example, about several tens eV), the damage given to the sample 22 is very small. Therefore, it is possible to etch the sample 22 to a predetermined final stage while suppressing the damage to the sample 22 as much as possible, and from a different viewpoint, removing the damaged portion generated by the ion beam etching in the previous step by ion etching. The fact that the etching has reached the final stage is detected by the above-described etching amount detection device, and thereby the generation of the plasma 50 is stopped and the etching is stopped.

Therefore, according to the etching apparatus as described above, it is possible to suppress the damage of the sample 22 as much as possible and prevent the etching rate from decreasing.

In the above description, an example has been described in which the control device 48 is used to automatically switch between ion beam etching and ion etching, but the control device 48 may not be provided, and both etchings may be switched manually, for example.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

Ion beam etching and ion etching can be switched for the same sample, whereby damage to the sample can be suppressed as much as possible and a decrease in etching rate can be prevented.

The gas source and the microwave oscillator are commonly used to extract the ion beam from the ion source and to generate plasma in the plasma generation space by using respective switching means, and the gas source and the microwave oscillator are shared. Since it is not necessary to separately provide the ion source and the plasma generation, the etching apparatus can be simplified.

By closing the shutter that interrupts the ion beam extracted from the ion source, a constant plasma generation space can be formed between the shutter and the surface of the disk containing the sample. As compared with the case where microwave power is supplied, a denser plasma can be generated near the sample on the disk. As a result, the etching rate of ion beam etching is increased and the processing speed is improved. Moreover, since the shutter that interrupts the ion beam is also used to form such a plasma generation space, the device configuration can be simplified also in this sense.

Since plasma is generated using microwaves also in the plasma generation space on the disk, the gas ionization efficiency is high and the cold air active species generation efficiency is high. Therefore, also in this sense, the etching rate of the ion beam etching is increased, and the processing speed is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an etching apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged partial cross-sectional view showing an example of the detection body used in the apparatus of FIG.
FIG. 3 is a schematic diagram showing an example of a detection signal output from the detection device of FIG. FIG. 4 is a schematic diagram showing an example of a conventional etching apparatus. FIG. 5 is a partial cross-sectional view showing an example of the sample. 2 ... ECR type ion source, 10 ... Microwave oscillator, 11 ...
… Gas source, 14 …… Ion beam, 16… Vacuum container, 18…
… Disk, 22 …… Sample, 24 …… Shutter, 36 …… Gas branch switch, 38 …… Circulator, 42 …… Detector,
44 ... Detection device, 46 ... Counting device, 48 ... Control device, 50
……plasma.

Claims (1)

[Claims] 1. An ECR type ion source for irradiating a sample on the disk with an ion beam in an apparatus for dry etching a sample on a rotary disk housed in a vacuum container, the ion source and the disk. And a shutter which is provided between the disk and a surface for intermittently opening and closing the ion beam extracted from the ion source and which forms a plasma generation space between the disk and the surface containing the sample when the shutter is closed. A gas source for supplying a gas, a microwave oscillator for generating microwave power, a gas switching means for switching the gas from the gas source to the ion source and the plasma generation space, and the microwave. A microwave switching unit that switches and supplies microwave power from an oscillator to the ion source and the plasma generation space, and opens the shutter. Switching the gas switching means and the microwave switching means to extract an ion beam from the ion source using the gas and microwave power supplied thereto and irradiate the sample on the disk with the ion beam. The etching apparatus is configured to switch between generating plasma in the plasma generation space by using the gas and microwave power supplied thereto.