JP2788436B2 - Ion beam etching equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion beam etching apparatus for performing etching by ion beam irradiation, and more particularly to an ion beam etching apparatus for reducing charge-up due to ion irradiation.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing technique, an ion beam etching apparatus is used to form various patterns. In this apparatus, a gas is introduced into an ion source to generate plasma by an appropriate means, ions are extracted from the plasma, and the object is irradiated with the ions to perform etching.

When an object to be processed is an insulator or a substrate on which an insulator is formed, positive charges of an ion beam are accumulated on the insulator, and are positively charged by so-called charge-up. For example, by etching a conductive substrate by reactive ion beam etching (RIBE),
When an insulator is used for the etching mask, positive charges are accumulated in the mask and charge-up occurs. And, due to the charge-up of the mask, an abnormal discharge occurs between the conductive substrate and the mask or the mask is positively charged.
The ion beam is bent at the mask portion, so that a so-called mylo-loading effect occurs, in which the etching depth depends on the pattern width, and the etching profile such as verticality of the etching side wall is deteriorated. Therefore, in the ion beam etching apparatus, it is important to suppress charge-up of an object to be processed.

Conventionally, a widely used technique for suppressing charge-up is to install a tungsten filament between an ion source and a processing chamber and generate a thermoelectron by heating the filament to a high temperature. There are methods that attempt to neutralize the ionic charge. As another example, a small plasma source such as a hollow cathode type plasma source is attached to generate an electron beam other than an ion source, and an inert gas such as an Ar gas is introduced to generate a plasma. It has been practiced to extract electrons and neutralize the positive charge of ions.

However, in this type of method,
There were the following problems. That is, when the tungsten filament is installed between the ion source and the object,
The filament is also exposed to the ions extracted from the ion source, and causes metal contamination of the workpiece by ion sputtering. Further, the temperature of the filament is extremely high, and degassing from the filament also causes surface contamination of the object to be treated. Furthermore, when a reactive gas such as oxygen, chlorine, or fluorine is used as the process gas, the gas reacts with the tungsten filament.
There is a problem that the filament is greatly deteriorated and a reactive gas cannot be used substantially.

When a hollow cathode type plasma source is used, it is necessary to flow a gas for plasma generation.
The pressure in the processing chamber increases. For this reason, process conditions for controlling the etching profile are restricted. In addition, when a reactive gas is used, there is also a problem that the hollow cathode portion is corroded and deteriorated.
Further, there is a problem that a space for mounting is required even in a small size, the volume of the process chamber needs to be increased, and the cost of the apparatus increases.

[0007]

As described above, in the conventional ion beam etching apparatus, when the object to be processed is an insulator or a substrate having an insulator mask or the like formed on its surface, it is charged by ion beam irradiation. Up occurs. If a tungsten filament is installed between the ion source and the object to be treated in order to suppress this charge-up, metal contamination and surface contamination of the object to be treated are caused, and further, a reactive gas cannot be used substantially. There is a problem. Also,
When a hollow cathode type plasma source is used, the process conditions are restricted, it is difficult to use a reactive gas due to the deterioration of the hollow cathode portion, and it is necessary to increase the volume of the process chamber, and the equipment cost is high. And so on.

In other words, when a new electron beam source such as a tungsten filament or a hollow cathode type plasma source is provided in order to suppress the charge-up, the electron beam source may be subjected to process conditions such as contamination of an object to be processed and an increase in pressure. Would be a serious constraint.

The present invention has been made in consideration of the above circumstances, and has as its object to suppress charge-up of an object to be processed without newly adding a mechanism serving as an electron beam source. It is an object of the present invention to provide an ion beam etching apparatus capable of improving the controllability and productivity in ion beam processing.

[0010]

[Means for Solving the Problems]

(Configuration) In order to solve the above problem, the present invention employs the following configuration. That is, the present invention provides an ion beam etching apparatus for etching an object to be processed by irradiation with an ion beam. A plasma source for generating plasma, an extraction electrode for extracting charged particles from the plasma source and irradiating the object to be processed, and applying a direct current voltage of a different magnitude to the extraction electrode in a pulsed manner at a constant period, thereby forming an ion beam. And means for alternately extracting an electron beam.In addition to this, the object to be processed is an insulator or a substrate on which an insulator is formed on the surface, and the object is irradiated with the ion beam. The ion beam irradiation time T is set so that the electric charge accumulated in the object to be processed is neutralized by the electron beam irradiation.
ion is set to Tion ≦ (Ve / Iion) (k / d), and the electron beam irradiation time Te is set to Te ≦ (Iion · Tion / Ie) (k / d). . Here, Ve is the voltage at which insulation breakdown occurs, Iion is the ion current density, k is the dielectric constant of the insulator, d is the thickness of the insulator, and Ie is the current density of the electrons.

Here, preferred embodiments of the present invention include the following. (1) The object to be processed was GaN formed on a sapphire substrate
Things. (2) The plasma source must be an ECR (Electron Cyclotron Resonance) plasma device using electron cyclotron resonance. (3) The extraction electrode is insulated from the chamber of the processing chamber and grounded, and a voltage for extracting charged particles is applied between the chamber of the plasma source and the ground terminal. (Operation) In the present invention, means for generating high-density plasma is not particularly limited, and E is generated by using electron cyclotron resonance.
Any plasma generation method such as a CR plasma source, an inductively coupled RF plasma source, or a capacitively coupled RF plasma source may be used. An electrode for extracting ions is attached to this type of plasma source. Usually, ions are extracted from high-density plasma by applying an extraction voltage to a plasma source chamber or an extraction electrode.

Here, it is also possible to extract electrons from the plasma source by applying a voltage having a polarity opposite to that of the ion extraction voltage as the extraction voltage or applying a voltage lower than the plasma potential as the extraction voltage. is there. That is, an apparatus normally used as an ion beam source can be used as an electron beam source by appropriately setting the magnitude or polarity of the applied extraction voltage. Furthermore, if the ion beam extraction voltage and the electron beam extraction voltage are alternately applied in a pulsed manner, the ion beam and the electron beam can be alternately extracted in a pulsed manner.

In the etching process using an ion beam,
Positive charges are accumulated on the surface of an insulator such as a mask, and so-called charge-up occurs. Therefore, when the electron beam is irradiated, the positive charges are neutralized and the charge-up can be suppressed. The essential difference between the conventional method and the present invention is that the conventional method simultaneously irradiates the ion beam and the electron beam, while the present invention irradiates the workpiece with the ion beam and the electron beam alternately in a pulsed manner. It is.

When the ion beam and the electron beam are alternately irradiated as in the present invention, at the time of the ion beam irradiation, positive charges are accumulated on the surface of the insulator, and a potential difference is generated between the insulator and the ground potential, thereby causing charge-up. . If charge-up progresses and the potential difference further increases, dielectric breakdown will eventually occur. If the electron beam is irradiated to neutralize the positive charge before the dielectric breakdown occurs, the dielectric breakdown can be suppressed. Furthermore, if the potential difference due to the accumulation of positive charges is negligible compared to the energy of the ion beam, if the electron beam is pulsed to neutralize the positive charges, the charge-up of the insulator can be ignored, Deterioration of the straightness of the ion beam can be suppressed.

In the present invention, means for monitoring the electric charge or potential on the surface of the workpiece during the ion beam processing is provided.
By feeding this back to the drive power supply for generating the extraction voltage, the conditions such as the pulse width, period, and amplitude of the ion beam and the electron beam during the ion beam processing can be optimized to the optimum value for the ion beam processing efficiency. The processing accuracy and productivity can be further improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. (First Embodiment) FIG. 1 is a schematic configuration diagram showing a dry etching apparatus according to a first embodiment of the present invention.

This apparatus is a so-called RIBE (Reactive)
It is an apparatus called Ion Beam Etching, which comprises a plasma generation chamber 11 and an etching chamber 12. The plasma generation chamber 11 is an ECR (Electron Cyclotron Resonance) plasma generation chamber, and an illustrated microwave generator is connected through a waveguide 13. A magnet coil 14 is provided around the plasma generation chamber 11. Then, a gas is introduced into the plasma generation chamber 11 and plasma is generated by utilizing a resonance phenomenon of microwaves and cyclotron motion of electrons.

In the etching chamber 12, a table 19 on which a workpiece 18 is placed is arranged. The mesh electrode 1 is located at the boundary between the plasma generation chamber 11 and the etching chamber 12.
5 is attached. In a normal etching apparatus, an extraction voltage is applied to the chamber of the plasma generation chamber 11 or the mesh electrode 15, and ions can be extracted from the plasma generation chamber 11. In the device used in this embodiment,
An amplifier power supply 16 capable of bipolar output at 20 kHz is connected to the chamber of the plasma generation chamber 11, and the amplifier power supply 16 is driven by a function generator 17. Thus, by controlling the magnitude and polarity of the applied voltage, ions and electrons can be made to have any period, pulse width,
It is possible to irradiate the workpiece 18 with a waveform.

In the present embodiment, the extraction voltage is applied to the chamber of the plasma generation chamber 11, but this may be applied to the mesh electrode 15, and the effect obtained is essentially the same. That is, a predetermined extraction voltage may be applied between the mesh electrode 15 acting as an extraction electrode for ions and electrons and the chamber of the plasma generation chamber 11. In this embodiment, ECR plasma is used as a means for generating plasma. However, the present invention is not limited to this. If it is possible to extract ions and electrons from the plasma, an inductively-coupled or capacitively-coupled plasma source or Kau plasma
The present invention is applicable to any device such as an fman type ion source.

Next, an example of an attempt to create a surface emitting laser array using the apparatus of this embodiment will be described. An object to be processed used in the present embodiment is formed on an n-type GaAs substrate 21 by molecular beam epitaxy (MBE).
AlAs Bragg reflection film 22, GaAs spacer layer 2
3, InGaAs active layer 24, GaAs spacer layer 2
5, a surface emitting laser wafer on which p-type GaAs / AlAs Bragg reflective films 26 are sequentially grown (FIG. 2A).
The total film thickness is about 6 μm. Thermal CVD on such a substrate
A 500 nm SiO ₂ film is deposited by a conventional method, and a circular Si having a diameter of 5 to 10 μm and a pattern interval of 5 μm is formed by ordinary photolithography and reactive ion etching (RIE).
An O ₂ film 27 was formed (FIG. 2B). And SiO
_An attempt was made to etch the surface emitting laser array using the _two films 27 as a mask (FIG. 2C).

After the above-mentioned substrate (workpiece) is attached to the holder in the sample exchange chamber, the holder is moved to the etching chamber 12, and the pressure in the etching chamber 12 is increased to 6.7 × 10 ^-4 P
Evacuate until a. Thereafter, the temperature of the substrate is raised to 170 ° C. by a heater embedded in the substrate holder, and the pressure of the etching chamber 12 is increased to 6.7 × 1.
It is kept until it reaches 0 ^-4 Pa or less. Plasma generation chamber 1
Chlorine gas is introduced into 1 and chlorine gas pressure is 5.3 × 10 ^-2 Pa
Then, the plasma was generated after the pressure was stabilized.
At this time, the shutter provided between the plasma generation chamber 11 and the etching chamber 12 is closed, and the substrate is not irradiated with charged particles. The microwave power during plasma generation was 200 W.

FIG. 3 (a) shows the sequence of the voltage applied to the plasma generation chamber in this embodiment, and FIG. 3 (b) shows the change in the ion current density and the electron current density depending on the applied voltage. Ion extraction voltage is 40
0 V and an electron extraction voltage of -5 V were applied in a periodic pulse shape. Hereinafter, description will be made according to this sequence.

The ion current density during ion irradiation is 0.5 m
A / cm ² , the electron current density during electron irradiation is 1 mA / c
m ² . Upon opening the shutter, the substrate is irradiated with ions and etching is started. However, since the SiO ₂ film formed as a mask is an insulator, positive charges are accumulated on the surface of the SiO ₂ mask by ion irradiation, so-called charge-up occurs. As a result, a potential difference is generated between the mask front surface and the mask back surface (the interface side between the mask and the substrate) with the SiO ₂ mask interposed therebetween. That is, the surface potential of the mask increases, resulting in a potential distribution on the substrate surface.

Surface potential ΔV (t) during ion beam irradiation
Is given by the following equation. ΔV (t) = Q (t) / C ₀ = Iion · Tion / (k / d) (1) where Q (t) is the amount of electric charge accumulated in the unit surface area of the insulator, and C ₀ is the insulation. The capacity per unit area of the film, Iion is the ion current density, Tion is the ion beam irradiation time, k is the dielectric constant of the insulating film, and d is the thickness of the insulating film. FIG. 3C shows the time change of the surface potential. The surface potential increases with the ion beam irradiation time, and the potential distribution on the surface of the workpiece increases.

When the surface potential is substantially the same as the ion extraction voltage, the energy of ions near the surface of the object to be processed becomes substantially zero, and ion sputtering of the object to be processed cannot be performed efficiently. Further, scattering of irradiation ions becomes remarkable due to the potential distribution on the surface of the object to be processed, and the etching efficiency is reduced. Therefore, the sequence is set so that electrons are irradiated at least while the surface potential is lower than the ion extraction voltage. Ion extraction voltage is V
Assuming acc, the ion beam irradiation time Tion needs to be such that Tion ≦ (Vacc / Iion) (k / d) (2) so that the surface potential does not exceed the ion extraction voltage.

Under the conditions of this embodiment, Vacc = 400
V, Iion = 0.5 mA / cm ² , k = 3.54 × 10
⁻¹¹ CV ⁻¹ m ⁻¹ , d = 0.5 μm, and the ion beam irradiation time should be at least 5.7 ms or less according to the equation (1). In this embodiment, the ion irradiation time is set to 5 ms. In addition, as shown in FIG.
The electron irradiation time was set to 2.5 ms so that Thereby, charge-up can be reduced.

If the electron irradiation is performed while the surface potential is desirably equal to or lower than the voltage at which dielectric breakdown of the SiO ₂ mask occurs, abnormal discharge due to dielectric breakdown of the mask can be completely suppressed. The voltage at which dielectric breakdown of the mask material occurs is V
Assuming e, the abnormal discharge can be completely suppressed by setting the ion beam irradiation time Tion to Tion ≦ (Ve / Iion) (k / d) (3). The electron irradiation time Te is given by Te ≦ (Iion · Tion / Ie) (k / d) (4) The frequency f for realizing this must be f ≧ 1 / (Tion + Te) (5).

The voltage at which dielectric breakdown occurs depends on the dielectric material used for the mask. In this embodiment, a SiO ₂ mask is used, and the breakdown voltage is about 40 V / μm. Under the above conditions of the present embodiment, the ion beam irradiation time Tion
Is set to 0.28 ms, the electron irradiation time is set to 0.14 ms, and the frequency is set to 2.4 kHz, abnormal discharge can be completely suppressed, and the influence of charge-up can be reduced.

FIG. 4A is a schematic view of an etching profile obtained according to the present embodiment. 41 in the figure is S
The iO ₂ mask 42 is an object to be etched. The influence of the scattering of the ion beam due to the charge-up of the mask was not recognized, and a good etching profile and in-plane uniformity were obtained. After etching, regrowth of AlGaAs on the side wall was performed by selective growth by MOCVD to reduce the surface recombination rate, and then an electrode forming process was performed, whereby a good surface emitting laser array could be formed. .

On the other hand, FIG. 4 shows an etching profile when only an ion beam is irradiated without performing electron beam irradiation.
(B). In this case, due to the charge-up of the SiO ₂ mask, a potential distribution is formed between the mask forming portion and the mask forming portion at the surface potential of the object to be processed, and scattering of the ion beam occurs. The effect is particularly prominent near the end of the mask where a wide SiO ₂ mask is formed. The straightness of the ion beam is lost, and ions are obliquely incident on the substrate. Dependence of pattern width on depth (microloading effect)
And the etching profile is degraded. Furthermore, when the charge-up proceeds, abnormal discharge occurs and the etching morphology is significantly deteriorated. As described above, when the effect of charge-up occurs in etching, it is not possible to produce a surface emitting laser array having good in-plane uniformity.

Although the effectiveness of the present invention has been described above by taking a surface emitting laser array as an example, the present invention is not limited to this embodiment.
It goes without saying that the present invention can be applied to a process of manufacturing other devices such as an ED, an optical amplifier, and an optical modulator.

In the above embodiment, the etching method is reactive ion beam etching (RIBE).
The dry etching method according to the present invention is not limited to this, but can be performed by chemical assisted ion beam etching (CAIB).
It can be applied to other dry etching such as E). (Second Embodiment) FIG. 5 is a schematic configuration diagram showing a dry etching apparatus according to a second embodiment of the present invention.
The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Although the basic configuration is the same as that of the first embodiment, this embodiment additionally has a means for measuring the surface potential of the object to be processed, and the measured value is fed back to the extraction voltage. I am trying to do it. In the figure, reference numeral 51 denotes a surface potential measurement device, and 52 denotes a surface potential measurement device power supply.

A case where etching is performed by this apparatus will be described. In the etching of a substrate in which an insulator mask is formed on a conductive epitaxial substrate, such as an object to be processed used in the first embodiment, not only the etching of the mask formation portion but also the insulator mask is etched. Therefore, the mask itself becomes thin. In the case where the epitaxial substrate has a multilayer structure having different compositions, the state of the surface of the object to be processed changes every moment as the etching proceeds.

Generally, in an ion beam processing apparatus, since the change in the surface state of the object to be processed is greatly affected, the ion current density, the electron current density, and the like may fluctuate with time. . Therefore, as in the first embodiment, it may not be sufficient to simply set the ion irradiation time and the electron irradiation time in the sequence of the extraction voltage in some cases. In order to perform more accurate control, the surface potential or the charge must be measured. It is necessary to change the ion irradiation time and the electron irradiation time based on the measurement result.

In this embodiment, the surface potential measuring device 51 is embedded on the substrate holder, the measurement result, the surface potential for switching from ion beam irradiation to the electron beam, which has been measured in advance, and the measurement from the electron beam irradiation to the ion beam irradiation. Was compared with the initial value of the surface potential, and feedback was applied to the extraction voltage control device. As a result, as shown in FIG. 6, the suppression of charge-up became more complete.

As a modification of the present embodiment, instead of measuring the surface potential of the object to be processed, the ion current density and the electron current density are measured on or near the holder, and the time integration of the current is performed. Feedback may be applied to the extraction voltage control device so that the integral value is equal to the integral value of the electron current.

Further, in the present invention, since the ion beam is irradiated in a pulsed manner, a rise in the temperature of the object to be processed, which is a problem in the conventional ion beam etching apparatus that continuously irradiates the ion beam, can be reduced. In by RIBE
FIG. 7 shows the temperature change on the substrate surface when the ions and electrons were continuously irradiated when the P was etched and when the ions and electrons were alternately irradiated in a pulsed manner as in the present invention. . At this time, the etching temperature was set to 180 ° C., Cl ₂ gas was used as the etching gas, and the ion acceleration voltage was 400 V and the microwave power was 200 W.

As a conventional example, electrons were continuously irradiated simultaneously with an ion beam using a hollow cathode type nut riser. In this case, the substrate temperature rapidly increased with the start of etching, and reached 220 ° C. after 10 minutes. On the other hand, when the ion beam and the electron are alternately irradiated in a pulse shape as in the present invention, the temperature is 10 ° C. immediately after the start of the etching.
Although a slight temperature rise was observed, the temperature reached a steady state and did not change thereafter.

When the substrate temperature changes during etching,
The etching rate also fluctuates, which directly leads to deterioration in the reproducibility of the etching depth and the controllability of the verticality of the etching side wall. For example, in the process of manufacturing an InP traveling-wave surface optical amplifier, vertical mesa etching of 20 μm is required. In such a deep mesa etching, a change in the substrate temperature during the etching is fatal for securing the verticality of the etching side wall.

FIG. 8 is a schematic view of a cross section of a substrate on which an InP-based traveling-wave surface optical amplifier of an InGaAsP active layer has been etched. In the figure, 81 is a semi-insulating InP layer, 82
a is an n-type InP carrier guide layer, and 82b is a p-type InP
A carrier guide layer; 83, an InGaAsP active layer;
Is a SiO ₂ mask. When the ion beam and the electrons were simultaneously and continuously irradiated, as shown in FIG. 8A, the side etching became larger as approaching the bottom surface. On the other hand, when the ion beam and the electrons according to the present invention were alternately irradiated in a pulse shape, a vertical mesa could be formed.

FIG. 9 is a schematic view of a traveling-wave optical amplifier formed by burying and regrowing after mesa formation. 91 in the figure
Is a semi-insulating substrate, 92 is a semi-insulating InP layer, 93a is n
Type carrier guide layer, 93b is a p-type carrier guide layer,
94 is an active layer, 95a is an n-type carrier injection layer, 95b is a p-type carrier injection layer, 96a and 96b are electrodes, 97 and 9
Reference numeral 8 denotes a resonator mirror. When side etching occurred during the mesa formation process, voids were formed at the interface during burying and regrowth, and a favorable interface could not be formed.
However, with respect to the sample mesa-etched according to the present invention, a good interface was obtained by burying and regrowth.

Another advantage of using the present invention is that the workability of the insulator can be improved. For example, the etching characteristics of GaN grown on a sapphire substrate by RIBE will be described. Cl is the etching gas
With _2, the ion acceleration voltage 500V, microwave power 200 W, the etching temperature were etched at 0.99 ° C..

First, when electron irradiation is not performed, the etching rate at a Cl ₂ pressure of 0.1 Pa is 65 nm / min.
Met. On the other hand, by alternately irradiating the ion beam and the electrons in a pulse shape, the etching rate is 90 nm / m.
in rose.

This is because, in the case of an etching method that does not irradiate electrons, in the case of an insulating substrate, the entire substrate has been charged up, and it is considered that the irradiation ion beam is scattered and the ion beam energy is reduced. .
On the other hand, when charge-up is eliminated by electron irradiation,
It is considered that the etching rate increased due to the effective ion sputtering.

As described above, electron beam irradiation is indispensable for ion beam processing of an insulating sample in order to improve processing efficiency and process controllability, and the present invention is particularly effective. Also,
The phenomenon that the etching rate is increased by the electron irradiation shown in the present embodiment is observed not only for GaN but also for AlN and InN grown on a sapphire substrate and their mixed crystals, and the group III nitride grown on the sapphire substrate Neutralization of charge by electron irradiation is considered to be an essential technology in device etching. The same effect can be expected not only with sapphire substrate but also with SiC.

[0047]

As described above in detail, according to the present invention, charge-up of an object to be processed is suppressed without newly adding a mechanism serving as an electron beam source other than a plasma source for generating an ion beam. And the apparatus cost can be reduced. Also, contamination of the object to be processed from the electron beam generator,
The controllability and productivity in the ion beam processing can be improved without any process restrictions such as pressure increase due to the introduction of the inert gas.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a dry etching apparatus according to a first embodiment.

FIG. 2 is a cross-sectional view showing an object to be processed used in the first embodiment and an etched state thereof.

FIG. 3 is a view showing a sequence of an extraction voltage in the first embodiment.

FIG. 4 is a schematic diagram of an etching profile obtained according to the first embodiment.

FIG. 5 is a schematic configuration diagram showing a dry etching apparatus according to a second embodiment.

FIG. 6 is a view showing a sequence of an extraction voltage in the second embodiment.

FIG. 7 is a diagram showing a change in substrate temperature during etching according to the present invention.

FIG. 8 is a cross-sectional view showing a state of a substrate etched according to the present invention.

FIG. 9 is a cross-sectional view illustrating the structure of a surface-type optical amplifier manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Plasma generation chamber 12 ... Etching chamber 13 ... Waveguide 14 ... Magnet coil 15 ... Mesh electrode 16 ... Amplifier power supply 17 ... Function generator 18 ... Workpiece 19 ... Table 51 ... Surface potential measuring device 52 ... Surface potential measuring device Power supply

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/3065

Claims (2)

(57) [Claims] An object to be subjected to etching is accommodated therein.
Processing chamber and a gas chamber disposed adjacent to the processing chamber.
And a plasma source that generates plasma
Drawing charged particles from the substrate and irradiating the object to be processed
DC voltage of different magnitudes
Is applied in a pulsed manner at a fixed period, and the ion beam and electron beam are applied.
Means for pulling out the arm alternatelyAEON B
Etching equipment, The object to be processed is an insulator or a substrate having an insulator formed on its surface.
A plate, wherein the object to be processed is irradiated with the ion beam.
Charge accumulated in the electron beam The ion beam irradiation time Tion is T
ion ≦ (Ve / Iion) (k / d) And the irradiation time Te of the electron beam is Te ≦ (Iion · Tion / Ie) (k / d) Ion beam etching equipment characterized in that
Place. Here, Ve is a voltage at which insulation breakdown occurs, and Iio
n is the current density of the ions, k is the dielectric constant of the insulator, d is the insulation
The body thickness, Ie, is the current density of the electrons. 2. The method according to claim 1, wherein the object to be processed is Ga on a sapphire substrate.
2. The ion beam etching apparatus according to claim 1, wherein N is formed .