JPH07320670A - Processing method and device using focused ion beam generating means - Google Patents

Abstract

PURPOSE:To enable the fine processing, fine film forming, and analysis of a specified point of a sample by irradiating a sample with the ion beam formed by focusing a specified ion, and processing the sample without hindering the electrical characteristic of the sample. CONSTITUTION:Micro wave is made to enter a 1/4 wave length resonance type semi- coaxial resonator 2, which is provided with a quartz glass tube 7 sealed with the inert gas, through a micro wave incident coaxial passage 1. Simultaneously, a wave length adjusting screw 3 is adjusted so as to supply the micro wave power to the resonator 2 in the maximum supplying condition, and the inert gas is ionized so as to generate the plasma 8, and the electromagnetic wave generated by a magnetism generating device 9 is made to enter so as to generate the high-density plasma. This plasma is withdrawn between a withdrawing electrode 4 and an accelerating electrode 5, and discharged from an electron discharging source 12, and a magnetic field is generated by an exciting coil 11, and this plasma is accelerated by the accelerating electrode 5 so as to obtain the focused ion beam 20. A sample 18 is irradiated with this ion beam 20 through three electrode lenses 14, astigmator electrode 15 and a deflector electrode 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for irradiating a device such as a semiconductor LSI with a focused ion beam to perform fine processing or fine film formation, and more particularly, to irradiate a focused ion beam from an ion source. The present invention relates to a processing apparatus and a processing method provided with a focused ion beam generating means which does not contaminate a sample such as a silicon wafer or a device with the substance to be treated.

[0002]

2. Description of the Related Art Focused Ion Beam:
(Hereinafter, abbreviated as FIB), there is a wide variety of devices using maskless ion implantation, ion beam lithography, mask repair, wiring repair in the semiconductor manufacturing field, SIMS (secondary ion mass spectrometry) in the analysis field, Examples of preparation of samples for observation include preparation of cross sections for SEM (scanning electron microscope) observation and preparation of thin pieces for TEM (transmission electron microscope) observation. A liquid metal ion source is often used in an apparatus using a focused ion beam, and gallium is widely used as an ionic element in an apparatus used for processing and correction. In addition, rare gas ions and oxygen ions from a duoplasmatron type ion source are often used in analyzers that perform microprocessing and analyze samples.

On the other hand, in each process such as ion implantation, lithography, etching, etc. in the semiconductor manufacturing process, whether each process meets the intended specifications, or the achievement of a desired shape is impaired by unexpected dust or the like. It is very important from the standpoint of improving the manufacturing yield that process control such as whether or not there is a defect, and if there is a shape defect, to correct it after each process. It is essential that such control be performed in the manufacturing line in order to avoid external contamination of the sample. So-called in-line observation, correction or analysis. At present, surface observation is performed in an actual manufacturing line using an optical microscope or a scanning electron microscope.

[0004]

The liquid metal ion source is
It is narrowed down to submicron and is actually used as a focused ion beam processing device for processing semiconductor LSIs and masks. However, the metal ions irradiated on the processed surface generally become an impurity and adversely affect the semiconductor manufacturing process after they play the role of physical impact, with the exception of some metal elements. become. Therefore, under the present circumstances, the liquid metal ion source cannot be actively used in the semiconductor manufacturing line.

Therefore, in order to clarify the problem to be solved by the invention, the problems found in the application of FIB, the ion source for the focused ion beam, and the problems of the ion source will be separately described below.

Problems found in FIB application FIB cross-section processing equipment, which is an equipment using FIB, for observing the local cross-section of an element, FIB correction processing equipment for correcting process defects and logic defects of the element, SIMS devices that use FIB to analyze the composition of specific parts are not used in mass production lines like optical microscopes and scanning electron microscopes currently used in semiconductor device manufacturing, and are exclusively used as test samples. Is performed on a sample taken from the manufacturing line or a sample for which the manufacturing process has been completed.

In other words, it is a premise that it is not returned to the manufacturing line again. The reason is that the device using the conventional FIB is
This is because contamination is given to the sample or the sample production line.

For example, if a Si wafer or a Si device has a G
When the above-described cross-section processing and SIMS analysis are performed using a-FIB, Ga is deposited on Si and the Ga functions as a p-type dopant (acceptor) for Si, causing electrical deterioration for a long period of time. Further, since the vapor pressure of Ga is very low, a deposition area of Ga is observed around the processing area by Ga-FIB. This goes beyond mere electrical pollution and leads to the formation of a conductive film, which causes a serious problem for the device such as a short circuit between wirings.

Further, even if local fine processing is performed by Si-FIB using a liquid metal ion source (LMIS) using an Au-Si alloy, Au particles evaporated from the LMIS are used as a sample Si wafer or Contaminates the device with heavy metals and adversely affects the device operation.

On the other hand, in the case of the above-mentioned duoplasmatron type ion source, by irradiating the processed surface in order to extract the ions existing therein by turning the inert gas into a plasma and to form a focused ion beam. Ions do not directly affect the semiconductor manufacturing process as impurities because they return to gas atoms or molecules again after they play the role of physical impact. However, since arc discharge is used for plasma generation, a high electric field or high temperature applied to the filament cathode mixes impurity metal ions into the plasma from the cathode, which adversely affects the semiconductor manufacturing process. Therefore, like the liquid metal ion source, it cannot be used in the semiconductor manufacturing line.

FIG. 2 shows an example of inspection of a semiconductor element to which a conventional processing apparatus using FIB is applied. In the semiconductor element manufacturing process, transistor elements and wirings are formed by performing film formation, etching, ion implantation, etc. on a silicon wafer. In this process, for example, it is necessary to inspect whether or not the processing can be correctly performed in a difficult process such as film formation in a deep hole or etching of a fine groove. In this case, the wafer is taken out from the previous process line, and the Ga ion FIB is placed at the position where the cross section of the device is to be observed and inspected.
A hole is processed by a processing device using (Ga-FIB), and its side wall is observed by SEM.

However, the Ga irradiated for Ga-FIB processing remains on the wafer, and this Ga adversely affects the device as described above. Further, when this wafer is returned to the manufacturing line, the contamination is spread to various manufacturing apparatuses on the line, and there is a possibility that the wafer manufactured by such a manufacturing apparatus is also contaminated. Therefore, as shown in FIG. 2, the wafer subjected to FIB processing for inspection was discarded without being returned to the manufacturing line again. But,
The wafer has a diameter of 200 mm, and it is very uneconomical to discard a high-value-added LSI having 100 to several hundreds of chips halfway formed on the wafer during the process for inspection. Since the wafer can be 300 mm in the future, this waste will become more and more ignorable in the future.

Further, since hundreds of chips are built in one wafer, if the process control by FIB is performed off-line as in the conventional case, the wafer 1 is processed or processed once.
It was uneconomical to remove the sheets from the line, waste the remaining elements that were not processed or analyzed.

FIG. 3 shows the situation regarding the yield of semiconductor devices. In the semiconductor device manufacturing process, the probability of occurrence of a fatal defect is defined as the fatal defect density α per unit area.
It is expressed in (pieces / cm ² ). Empirically, α decreases from the trial production stage to the mass production stage, but never becomes 0 and becomes 1 to several pieces / cm ² . Fatal defects that occur in a layer produced by a certain process increase in proportion to the chip area. In other words, the yield of non-defective products when viewing only a certain layer β
3 decreases as the chip area increases, for example, when the chip area is 14 mm □, that is, 1.96 cm ² , the yield is (1-1.
6α) × 100%.

On the other hand, a semiconductor device is formed of many layers. FIG. 4 shows the yield of chips when the number of wiring layers is plotted on the horizontal axis and the yield β for each layer is assumed to be constant. If all n wiring layers cannot be made good, the chip cannot be a good product, and the chip yield is β to the nth power. As the trend of semiconductor devices, the chip area is increasing more and more, and the total number of wirings is increasing to 4 to 6 layers especially in the logic LSI. Therefore, if the fatal defect density α is constant,
Chip yield tends to decrease. Therefore, in the future, non-defective chips cannot be acquired unless the defects caused by the process are corrected for each layer. FIB for this correction
It is preferable to use the processing using, but as described above, once Ga-FIB processing is performed for the correction, it cannot be returned to the manufacturing process, so the correction in the middle of the process is realized. could not.

From the above background, there has been a demand for a processing method using FIB and an apparatus for realizing the processing method, which can process the sample inline without contaminating the sample such as a wafer or a device.

A method of processing an ion beam in a semiconductor device is disclosed in "Ion beam processing method" (known example 1) of Japanese Patent Application Laid-Open No. 2-90520. In this publicly known example 1, it is shown that the semiconductor device is a Si substrate, and at least one of Si, C, Ge, Sn, and Sm is used as an ionic species. An example in which an Au-Si alloy (Au ₈₂ Si ₁₈ ) is used as an ion source is shown in the document, and it is described that Ge and Sm can be obtained from alloys such as Al and Au.

A liquid metal ion source (Liquid Metal I
on Source, LMIS for short, and Electrohydrodynamic Ion Source, EHD for short.
Ion source) is the same, there is no difference in the configuration.

Ion Source for Forming Focused Ion Beam In order to process Si substrate or device without electrical contamination by FIB, the energy level of impurity atoms is not within the bandgap threshold of Si energy level. It is clear that Si ions and Ge ions are suitable. Further, inert elements such as Ne, Ar, Kr, Xe, etc. are also suitable.

The simplest method for obtaining a Si or Ge ion beam from an LMIS or EHD ion source is to use an alloy containing Si or Ge as an ionic material to operate by lowering the melting point or vapor pressure of the ionic material and then operating the FIB optical system. This is to select and focus only Si +, Si ² + ions and Ge +, Ge ² + ions by an E × B mass analyzer provided in the system. Well-known Si-based alloys are Au-Si, Pt-S
i, Al-Si alloys, etc., and Ge-based alloys are Au-
Ge, Fe-Ge, Pt-Ge, Cu-Ge and the like.

As described above, when Si or Ge ions are to be released, Au, Cu, Fe, and
It is generally known to use an alloy with Pt or the like. However, using these alloys as an ionic material means that, as explained in the previous section, the Si element, which is the workpiece, is made into an element other than the alloy components Si and Ge (for example, Au, C
Since it is contaminated with u, Pt), the non-contamination inspection required for the in-line inspection is not performed. In particular, it is well known that bringing heavy metals such as Au and Pt into the Si semiconductor manufacturing line is taboo.

On the other hand, as explained in the previous section, in the case of the duoplasmatron type ion source, since arc discharge is used for plasma generation, impurity metal ions are generated from the cathode due to the high electric field and high temperature applied to the filament cathode. It mixes in the plasma and, as a result, adversely affects the semiconductor manufacturing line.

Therefore, in order to realize the non-contamination inspection by the FIB, whether Si simple substance, Ge simple substance or liquid inert element is used as the optimum ion material of the EHD ion source,
It turns out that it must be an inert element from the plasma source that is free of impurities.

Problems of the current ion source Si alone has a melting point of 1407 ° C. and a vapor pressure of 4 × 10 at the melting point.
Since it was very high at ~ ⁴ (Torr), it was difficult to control the temperature and the thermal evaporation of the LMIS, and it was not practical as an ionic material of the LMIS. On the other hand, the melting point of Ge alone is 947.
° C., a vapor pressure of 1x10 ~ ⁶ (Torr), as compared with Si, the melting point is very low, it is promising as a vapor pressure low ionic material at the melting point. However, W (tungsten), which has been widely used as an emitter material for LMIS, is replaced with S
When used as an emitter of i-LMIS or Ge-LMIS, Si and Ge are active, so that W is eroded in a short time and the role of the emitter is lost.

Ta and M used as emitters
For high melting point metals such as o and Re, molten Si and Ge
When it is dipped in, it is eroded and destroyed in a few hours, and there is a problem that the life of these LMISs is extremely short. Further, SiC, which is a ceramic material, has a problem that it does not get wet with molten Si and Ge at all, and does not serve as an emitter.

Therefore, there is almost no attempt to release Si ions and Ge ions from LMIS using simple Si or Ge as an ionic material. Even though reports of ion emission using simple Si or Ge are seen, it is extremely short time, and it is reported that the emitted ions are focused, Si-FIB or Ge-FIB is formed, and the sample is processed. I haven't. Therefore, the search for an emitter or reservoir material that is not eroded by molten Si or Ge and that can maintain stable wetting for a long time is an important issue for realizing Si-LMIS or Ge-LMIS.

In the above-mentioned publicly known example 1, dare Si or Ge is intentionally used.
The reason or effect that a simple substance or an alloy of Si and Ge must be used as an ionic material is not described, and a FIB emitted from an ion source using a simple substance of Si or Ge as an ionic material is used for fine processing of a semiconductor element. There is no disclosure of a method or suitable ion source configuration (emitter material, reservoir material) for achieving this.

Further, in order to obtain a focused ion beam apparatus containing no impurities by the plasma ion source, it is basically effective to generate ions by plasma containing no impurities, and it is necessary to apply a discharge mechanism which does not generate impurities. As a result of study, in the conventional ion extraction mechanism from plasma, the electric field for extracting ions and the electric field for acceleration are the same electric field and cannot be controlled independently. Therefore, an unnecessarily high electric field may be applied between the extraction electrode and the plasma to cause dielectric breakdown. Also, it is difficult to control the ion sheath surface that emits ions,
For this reason, the unidirectionality of the extracted ions is weak, and it is difficult to achieve a submicron beam diameter.

The above problems can be summarized as follows: (1) Conventional devices using Ga-FIB and SIMS devices cannot be used in the Si semiconductor device manufacturing line because they are contaminated. There is no inspection / correction apparatus using an ion source, which replaces Ga-FIB and does not cause contamination of wafers and devices, as a means for performing inspections and corrections on a semiconductor device manufacturing line.

(2) Si simple substance, Ge simple substance, or Si
There was no Si-LMIS or Ge-LMIS capable of long-lived and highly stable ion release using / Ge alloy as an ion material.

(3) There was no contaminant-free high-intensity ion source for focused ion beam devices.

(4) Since there is no apparatus using an FIB whose ion species are Si ions, Ge ions, inert gas ions, etc., which are not sources of contamination of Si wafers and Si devices, Si wafers and Si wafers using these FIBs are not available. It could not be inspected or modified without polluting the device.

Therefore, an inspection or correction method for overcoming such a problem (1) is created, and further problems (2) and (3) of the ion source for realizing the method are solved and the ion sources are mounted. However, it has been desired to realize an inspection or correction device using the FIB that overcomes the problem (4).

Therefore, an object of the present invention is to produce Si wafers and S
Focused ion beam generation means capable of irradiating a sample such as an i-device with FIB to perform microfabrication, fine film formation and analysis on a specific portion of the sample without causing electrical contamination or contamination due to beam irradiation. It is to provide a processing apparatus and a processing method provided with.

[0035]

The above object of the present invention is to generate ions that do not affect the electrical characteristics of the sample to be treated, and focus the generated ions to form an ion beam, It is achieved by a treatment method using a focused ion beam generating means, which comprises irradiating a sample with the formed ion beam and treating the sample without impairing the electrical characteristics of the sample.

A further object of the present invention is to provide a processing apparatus using a focused ion beam generating means with a plasma ion source for generating ions that do not affect the electrical characteristics of the sample, and a plasma ion source for generating the ions. Ion beam forming means for extracting ions from the plasma to form an ion beam, ion beam focusing means for focusing the formed ion beam, irradiation means for irradiating the sample with the focused ion beam, and irradiation processing It is achieved by providing a sample chamber in which a sample is installed.

Further, an object of the present invention is to provide a processing device equipped with a focused ion beam generating means, and a plasma ion source for generating ions which do not affect the electrical characteristics of the sample even when the sample is irradiated with the plasma ion source. An ion beam forming means having a beam diameter changing means for extracting ions from plasma generated by a plasma ion source to form an ion beam having a desired diameter; an ion beam focusing means for focusing the formed ion beam; This is achieved by providing an irradiation unit that irradiates the sample with the generated ion beam and a sample chamber in which the sample to be processed by irradiation is installed.

Another object of the present invention is to provide a processing apparatus equipped with a focused ion beam generating means, an ion source for generating ions which do not affect the electrical characteristics of the sample, and an ion generated by the ion source. An ion beam forming means for extracting the ion beam to form an ion beam, an ion beam focusing means for focusing the formed ion beam, an irradiation means for irradiating the sample with the focused ion beam, and a sample to be processed by irradiation. And a sample chamber.

[0039]

The ion source for generating ions that do not affect the electrical characteristics of the sample to be treated is composed of a plasma ion source, a field ionization ion source, or an EHD ion source, and neon, krypton, or argon is used. The electrical conductivity of the sample can be improved by using an inert gas, such as zirconium, zenon, or nitrogen, or a material that does not affect the electrical characteristics of the sample when it is irradiated. The contamination caused by metal contamination that adversely affects the characteristics is prevented.

In particular, when the sample is a silicon wafer or a silicon device, a material that does not affect the electrical characteristics of the sample even when the sample is irradiated, is silicon alone, germanium alone or silicon / silicon / silicon. By using the EHD ion source using a germanium alloy, irradiation of the sample with FIB obtained therefrom does not cause metal contamination that adversely affects the electrical characteristics of the sample.

In the case of a plasma ion source, a high density plasma is generated by electrodeless discharge,
Since there is no electrode that directly participates in discharge and ions that do not contain metal species can be generated, contamination by metal contamination that adversely affects the electrical characteristics of the sample does not occur.

In the case of a plasma ion source, the ion extraction port of the extraction electrode is set to have a radius smaller than the thickness of the ion sheath, so that plasma is prevented from diffusing from the extraction port to the acceleration electrode side. It suffices to apply a relatively small voltage to the electrodes to extract the ions in the plasma. That is, by applying a voltage to the extraction electrode with respect to the reference electrode installed in the plasma, an electric field is efficiently applied to the plasma,
With a low voltage of several tens of volts, theoretically the maximum amount of ions can be extracted, and the dielectric breakdown in the vicinity of the extraction electrode that occurs in the conventional device does not occur.

Further, in the case of the plasma ion source, an ion sheath control electrode for controlling the shape of the sheath surface is provided on the extraction electrode to increase the ion emission area.
The ion current density increases. Further, by emitting electrons from the focusing electron emission source provided between the extraction electrode and the acceleration electrode to the extraction electrode side, the space charge effect on the ions with high charge density that have not been sufficiently accelerated near the extraction port. Are suppressed, the ion beam is trapped in the radial direction at the valley of the potential formed around the central axis, and the current limitation in the axial direction is relaxed. Further, by generating a magnetic field for confining the emitted electrons in the radial direction by the exciting coil, the radial diffusion of the ion beam trapped in the potential valley can be suppressed.

Further, the beam diameter changing means of the plasma ion source changes (1) the electron density of the plasma by changing the input power to the plasma generating section, and controls the voltage applied to the ion extracting electrode to extract the electrode. By setting the thickness of the ion sheath generated on the front surface of the substrate to a desired thickness, an ion beam having a desired diameter can be extracted without reducing the ion current density. By using a parabolic extraction electrode, changing the input power to the plasma generation part to change the electron density of the plasma and changing the shape of the ion emission surface near the extraction electrode, it is possible to reduce the ion current density to the desired value. By extracting an ion beam with a diameter,
(3) An extraction electrode having a movable structure having a plurality of extraction ports having a desired diameter is used, and the extraction port corresponding to the desired ion beam diameter is moved to the ion beam extraction position to change the ion current density. By extracting an ion beam having a desired diameter without decreasing it, (4) application of a sheath surface control electrode is performed by using an extraction electrode composed of a sheath surface control electrode and a porous electrode having an insulating plate. By controlling the voltage and changing the shape of the ion sheath surface on the extraction electrode to extract ions only from the desired holes of the electrode without decreasing the ion current density to form an ion beam having a desired diameter, (5) The electron density of the plasma is changed by changing the power applied to the plasma generating part, and the taper insulating spacer and mesh are provided below the extraction electrode. By providing an electrode and controlling the voltage applied to the extraction electrode and the mesh electrode to change the plasma region to form an ion beam having a desired diameter, (6) a movable extraction electrode is used. An ion beam having a desired diameter can be obtained by extracting the ion beam having a desired diameter without reducing the ion current density by mechanically switching the ion passage port in combination with an accelerating electrode.

Further, by using a focused ion beam apparatus using a plasma ion source with a variable beam diameter as described above, fine processing of a deep structure of a sample, formation of a new structure or a signal from a cross section can be obtained. The observation and analysis of the sample can be performed at high speed without contaminating the sample.

[0046]

【Example】

(Example 1) In Example 1, a focused ion beam (FI) was used.
A plasma ion source as the ion beam generating source of B) will be described with reference to FIGS. 1 to 27.

FIG. 1 is a block diagram of a processing apparatus using a focused ion beam, which uses a microwave discharge plasma by a quarter wavelength resonance type semi-coaxial cavity resonator as an ion source. Figure 1
In the figure, 1 is a microwave incident coaxial line, 2 is a quarter wavelength resonance type semi-coaxial cavity resonator, 3 is a wavelength adjusting screw, 4 is an extraction electrode, 5 is an accelerating electrode, 6 is a reference electrode, and 7 is a quartz glass tube. , 8 is the generated plasma, 9 is a magnetic field generator,
10 is a vacuum container for processing work, 11 is an exciting coil, 12 is a focusing electron emission source, 13 is a blanking electrode, and 14 is 3
A single-electrode lens, 15 is a stigmator electrode, 16 is a deflector electrode, 17 is a secondary particle detector, 18 is a workpiece, 19 is a stage, 20 is a focused ion beam, and 21 is a secondary particle.

First, the operation of the plasma ion source according to the present invention will be described with reference to FIG.

2.45GH through the microwave incident coaxial line 1
The microwave of z enters the quarter wavelength resonance type semi-coaxial resonator 2. A quartz glass tube 7 in which an inert gas is filled is installed in the quarter wavelength resonance type semi-coaxial resonator 2. By adjusting the wavelength adjusting screw 3, microwave power is supplied to the quarter-wavelength resonance type semi-coaxial resonator 2 under the maximum supply condition. At this time, the inert gas is ionized into plasma 8. The plasma 8 is EC generated by the magnetic field generated by the magnetic field generator 9 and having a magnetic flux density of 875 Gauss near the outlet.
Since an R (Electron Cyclotron Resonance) effect is caused and an electromagnetic wave is incident above the cutoff frequency of plasma, a high density plasma of 10 ¹² to 10 ¹³ / cm ³ is locally generated.

Ions existing in the plasma 8 are extracted from the extraction electrode 4 and the acceleration electrode 5 through the extraction port opened in the extraction electrode 4 which is provided with a negative potential with respect to the reference electrode 6 installed in the plasma 8. Be drawn into the space between. The extracted ions are accelerated by the accelerating electrode 5 toward the workpiece 18 in the processing vacuum container 10 and become a focused ion beam 20.

By the way, the energy of the ions required for processing is several tens of kiloelectron volts, whereas the ions immediately after leaving the extraction port have several tens of electron volts, so m _i is the mass of the ions. , V _i is the ion velocity, q is the charge amount, and V is the acceleration voltage.

[0052]

[Equation 1]

Therefore, the velocity of ions immediately after leaving the extraction port is only about 3% of the velocity of ions required for processing. Here, Q ₁ is the charge density near the outlet, Q ₂ is the charge density after acceleration, v _i1 is the velocity near the outlet, v _{1
If i2} is the velocity after acceleration, S ₁ is the beam cross-sectional area near the extraction electrode, and S ₂ is the beam cross-sectional area after acceleration,

[0054]

[Equation 2]

And the amount of charge per unit length is inversely proportional to the speed.

Therefore, since the amount of charge of the ions immediately after leaving the extraction port is larger than that after acceleration, the ions repel each other due to the charges of the ions themselves, and the beam spreads as the velocity increases. In order to prevent this effect, electrons having a charge opposite to that of the ions are emitted from the electron emission source 12, and a magnetic field is generated by the exciting coil 11, and the electrons are collected near the extraction port by the force of the interaction between the electric field and the magnetic field. And neutralize the repulsive force between the ions. The focused ion beam 20 that has passed through the acceleration electrode 5 passes through the blanking electrode 13. The blanking electrode 13 is made up of two electrode plates. By applying an electric field between these electrodes, the trajectory of the focused ion beam 20 is changed so that the focused ion beam 20 does not reach the workpiece 18. That is, it has a function of turning on and off the focused ion beam 20.

When the blanking electrode 13 does not operate,
The focused ion beam 20 is incident on the three-electrode lens 14,
By controlling the voltage of the three electrodes, the beam diameter and beam current density required for processing can be obtained. Subsequently, the focused ion beam 20 is incident on the stigmator electrode 15, and the astigmatism due to the asymmetric component of the three-electrode lens 14 is compensated. Focused ion beam 2 that has become the performance required for fine processing
Although 0 is irradiated to the work piece 18, sufficient movement position accuracy cannot be obtained only by moving the stage for fine processing. Therefore, the electric field in the deflector electrode 16 changes the trajectory of the focused ion beam 20 more finely to perform processing at an arbitrary position.

Next, the ion extraction mechanism of the plasma ion source according to the present invention will be described in comparison with a conventional plasma ion source.

Conventionally, when the ions are extracted from the plasma by an electric field, since the ions are extracted through the ion extraction port opened in the wall in contact with the plasma, the plasma should contact the wall having the extraction port (not limited to the conductor or the non-conductor). As a result, due to the mass difference between electrons and ions, a region called a sheath in which the charge neutral condition, which is a characteristic feature of plasma, does not hold is generated.

Further, in most cases, ions are heavier than electrons, so that ions are excessive in the vicinity of the wall in order to keep the balance of the current due to the ions and the current due to the electrons, resulting in an ion sheath. If the gas pressure of the gas to be turned into plasma is from several Pascals to several tens of Pascals, it can be treated as collision-free plasma without collision of particles in the sheath, and it can be treated as "Plasma DIAGNOSTIC TECHNIQUES, ACADEMI".
The maximum ion current density that can be derived can be estimated from the sheath generation theory of C PRESS, NEW YORK, 1965).

The potential inside the ion sheath is lower than the plasma potential, and the portion from the position where the potential is one-half the electron temperature Te lower than the plasma to the wall is defined as the sheath. At this time, the ion saturation current density Ji flowing from the plasma is

[0062]

[Equation 3]

It is represented by Here, Ne is the electron density in the plasma, and k is the Boltzmann constant. Therefore, using Argon gas as an example, the maximum ion saturation current density Ji that can be extracted from plasma using Equation 3 is calculated using the electron density Ne as a parameter, as shown in FIG.

By the way, in recent years, the focused ion beam used for semiconductor fine processing and SIM image observation has a beam diameter of 0.1 μm.
A current of about 1 nA at m, that is, a current density of 10 ⁵ A / m ² is required. Therefore, even if the beam diameter is focused to 1/10 using the ion optical lens of the three-electrode lens 14, the ion current density extracted from the ion source must be at least 10 ³ A / m ² . Therefore, when the electron temperature of several electron volts to obtain a current density 10 ³ A / m ² from FIG. 2, 10 ¹³ / cm ³ plasma near the electron density is required.

On the other hand, the distance at which the plasma, in which gas is ionized into ions and electrons, can be regarded as neutral, that is, the Debye length λ.
d is the dielectric constant of the vacuum is ε ₀ ,

[0066]

[Equation 4]

The electron density Ne is calculated from the result (FIG. 6) calculated with the electron density Ne as a parameter.
The Debye length λd for ¹³ / cm ³ is several μm.

If the initial velocity of the ions can be neglected, the electrode potential is set to V by the Langmuir-Child rule of 3/2.
_P , sheath end potential V ₀ (seed generation conditions, electron temperature Te
-1/2), and assuming that the sheath thickness is α, the ion saturation current density Ji is

[0069]

[Equation 5]

It becomes Therefore, when the sheath thickness α is obtained from the equations 3 and 5 using the electron temperature Te as a parameter, the thickness of the flat plate electrode on the front surface is as shown in FIG. 7 according to the potential difference between the electrode and the sheath end potential. The ion sheath of the sea urchin will be formed.

In FIG. 7, V _F is called a floating potential and is the sheath end potential and the inter-electrode voltage when the current flowing from the plasma 8 to the electrode is zero. Therefore, when no voltage is applied to the electrodes, a thickness of 10 μm, which is several times the Debye length, is formed on the front surface of the electrodes.
There is always a degree of ion sheath.

Conventionally, in the case of a focused ion beam processing apparatus using a plasma ion source, the ion extraction mechanism is as shown in FIG.
The extraction voltage is applied to the acceleration electrode 5 with reference to the conventional extraction electrode 28 having the structure shown in FIG. When no voltage is applied between the conventional extraction electrode 28 and the acceleration electrode 5, the thickness D _S of the ion sheath 22 is smaller than the extraction aperture diameter D _H, and the region of the plasma 8 extends beyond the extraction port to the acceleration electrode 5. Is spreading. Since only ions cannot be extracted in this state, as shown in FIG. 9, a high voltage is applied to grow the ion sheath 22 in the vicinity of the accelerating electrode 5 and the plasma 8 causes the extraction port of the conventional extraction electrode 28 to exit. It is necessary to ensure that it does not spread to the acceleration region.

For example, the extraction mechanism of a focused ion beam processing apparatus using a conventional plasma ion source has an electron temperature of 1
Since the Debye length is 25 μm from FIG. 6 using eV and a relatively low density plasma with an electron density of 10 ¹¹ / cm ³ , the sheath thickness D _S at the floating potential VF is several times that, about 100 μm. When DH is 1.5 mm and a voltage of 10 kV is applied between the conventional extraction electrode 28 and the acceleration electrode 5, the insulation distance dg between the electrodes under a pressure of 10 mPa or less.
(Cm), dielectric breakdown voltage Vb (V)

[0074]

[Equation 6]

Since the relationship of is established, the distance between the conventional extraction electrode 28 and the acceleration electrode 5 is 4 mm.

However, since the dielectric breakdown voltage of the ion sheath 20 is lower than the dielectric breakdown voltage in the vacuum of the equation 6, dielectric breakdown occurs between the plasma and the electrode, and it cannot be sufficiently extracted.

[0077] In the present invention, rather than a pull-out mechanism of an electric field for accelerating the electric field for extracting ions as in the conventional described above are the same, as shown in FIG. 10, to always drawer diameter D _H Then, by operating in a state where the ion sheath thickness D _{S1 at} the floating potential is ½ or more of that, the plasma 8 is spread beyond the extraction electrode 4 to the acceleration region even when no voltage is applied to the extraction electrode 4. However, by directly applying a voltage to the extraction electrode 4 with respect to the reference electrode 6 in FIG. 1 that is larger than the area of the extraction electrode 4 and is in contact with the plasma 8, the sheath thickness D can be reduced even at a voltage as low as several tens of volts. It is possible to extract ions up to the saturation current value through the ion sheath 22 that has become _S2 .

Therefore, in order to obtain the beam diameter of the focused ion beam for microfabrication of 0.1 μm, the extraction electrode having the extraction aperture of 1 μm is used in the case of the present invention because the three-electrode 14 is used to reduce the beam diameter to 1/10. 4 is used. The density is 10 ¹³
With a plasma 8 of / cm ³ , the ion sheath thickness D _S1 is 10
It is about μm and satisfies D _S1 ≧ 1 / 2D _H. Also, even if the extraction voltage is changed, the ion emission surface and the extraction electrode surface are always parallel, so the ion current density is constant, but the ions are accelerated perpendicularly to the extraction electrode surface, so compared to the conventional extraction mechanism. At the point of time when the beam has passed through the extraction port, it is possible to generate a beam having a good focusing property, which has no beam spreading component. That is, since the extraction electric field of the ions and the acceleration electric field after the extraction can be controlled independently, the high electric field is not directly applied to the sheath, and it is possible to extract the ions to the limit value without dielectric breakdown. Become. No voltage is applied to the ion sheath control electrode 24 on the insulator 25.

On the other hand, as shown in FIG.
A voltage is applied from an external power supply to the ion sheath control electrode 24 electrically insulated by the insulator 25 to bring it closer to the plasma potential, or a filament material is used for the ion sheath control electrode 24 to perform current heating or infrared laser heating. By performing thermionic emission by, it is possible to control the shape of the sheath surface in front of the ion sheath control electrode 24. For example, by forming a concave ion emitting surface, the ion emitting area is made larger than that of a flat surface. Then, by increasing the ion current density or by further finely adjusting the parallelism between the sheath surface and the extraction electrode in FIG. 11, the unidirectionality of the emitted ions can be improved.

The ion sheath control electrode 24 can also be applied to the conventional extraction mechanism (FIG. 9), and the shape of the ion emitting surface can be controlled. By changing the polarity of the voltage with respect to the plasma of each of the electrodes 4 and 24, the electron gun can be operated as it is.

Next, since the extraction electric field and the acceleration electric field can be independently controlled by the extraction mechanism, an acceleration mechanism for accelerating the ions emitted from the extraction port to a speed necessary for fine processing is required. Therefore, the ion acceleration mechanism in the present invention will be described with reference to FIGS. 12 to 14.

Ions having a strong unidirectionality emitted from the extraction port are accelerated by the accelerating electric field between the extraction electrode 4 and the acceleration electrode 5. However, as described above, the low-velocity ions near the extraction port have a large charge amount. In addition, the Coulomb force with the same charge causes the space charge effect. This space charge effect is mainly (1) ion beam divergence in the radial direction, and (2) current limitation by axial space charge limitation, and is directly related to the properties of the ion beam. Therefore, it is necessary to suppress the space charge effect in order to improve the focusing effect in the ion optical systems 14, 15 and 16 after acceleration in FIG. 1 and obtain a focused ion beam required for fine processing.

Conventionally, in order to suppress the space charge effect, the space charge is neutralized by charged particles. For example, in the case of an ion beam, the focused ion beam 20 is irradiated with the electron beam 26 from the focusing electron emission source 12 as shown in FIG. In this case, the spatial potential is φ, and the focused ion beam 2
When the charge density of 0 is ρi and the charge density of the electron beam 26 is ρe, Poisson's equation is

[0084]

[Equation 7]

It becomes

When the charge density ρe of the electron beam 26 is higher than the charge density ρi of the focused ion beam 20, apparently from Equation 7, only electric charges by electrons are generated, and a potential valley is formed around the beam center axis. Ions are trapped in this potential valley and the divergence of the beam is suppressed. Furthermore, the axial space charge limitation due to Langmuir Child's 3/2 law can be relaxed by neutralizing the space charge. In addition,
In FIG. 12, the width of the drawing is magnified 50 times with respect to the length.

However, the space charge neutralization method cannot control the diameter of the valley of the potential, so that the ion beam focusing effect cannot be sufficiently obtained. On the other hand, in the present invention,
As shown in FIG. 12, not only the charge density ρe of the electron beam 26 is increased with respect to the charge density ρi of the focused ion beam 20 from the electron emission source 12 to generate a potential valley in the radial direction, but also the acceleration region. 2 is used to generate the confining magnetic field for the electron beam 26 shown in FIG. The AA 'cross section in FIG. 12 at this time is
It is shown in FIG. The exciting coil 11 is composed of four winding coils. In each winding coil, a current flows from the back side of the paper toward the front direction, and a magnetic field having a magnetic flux density B is generated.

This magnetic field gives a force F by E × B shown in FIG. 12 to the electron, and the electron beam focusing region 27 shown in FIG.
Confine the electron beam to. As a result, the intensity of the magnetic field controls the electron beam focusing region 27, that is, the region of the potential valley, and the beam diameter of the focused ion beam 20 and the space charge limitation in the axial direction can be controlled. Further, as shown in FIG. 14, when a current is applied to the left and right winding coils of the exciting coil 11 from the front side to the back side of the drawing, the shape of the electron beam focusing area 27 changes, and the shape of the focusing area of the focused ion beam 20 is changed. Can also be controlled.

As described above, in the plasma ion source according to the first embodiment of the present invention, the ions are diffused from the extraction port to the acceleration electrode side by setting the ion extraction port of the extraction electrode to have a radius smaller than the thickness of the ion sheath. Therefore, it suffices to apply a relatively small voltage for extracting the ions in the plasma to the extraction electrode. That is, by applying a voltage to the extraction electrode with respect to the reference electrode installed in the plasma, an electric field is efficiently applied to the plasma, and theoretically maximum ions can be extracted with a low voltage of several tens of volts. As a result, the problem of causing dielectric breakdown near the extraction electrode of the plasma ion source, which has occurred in the conventional device, has been solved.

Further, by providing an ion sheath control electrode for controlling the shape of the sheath surface on the extraction electrode and increasing the ion emission area, the ion current density could be increased.

Further, by emitting electrons from the focusing electron emission source provided between the extraction electrode and the acceleration electrode to the extraction electrode side, ions with a large charge amount that have not yet been sufficiently accelerated near the extraction port. The space charge effect on the ion beam is suppressed, the ion beam can be trapped in the radial direction at the valley of the potential formed around the central axis, and the current limitation in the axial direction can be relaxed. Further, by generating a magnetic field for confining the emitted electrons in the radial direction by the exciting coil, it becomes possible to suppress the radial diffusion of the ion beam trapped in the valley of the potential. As a result, an ion beam with a high current density can be extracted from the plasma ion source.

By constructing a focused ion beam processing apparatus using the plasma ion source according to the present invention described above, that is, high-density microwave plasma consisting of 1, 2, 3, 7, 8, and 9 in FIG. Generation mechanism, 6 in FIG. 1, ion extraction mechanism consisting of 4, 24, 25 in FIG. 10, 11 in FIG. 1, 4 in FIG.
By using the electron beam / magnetic field focusing mechanism consisting of 5 and 12 and the ion optical system consisting of 14, 15 and 16 in FIG. 1, as compared with the conventional focused ion beam processing apparatus using the plasma ion source, 1 having a beam diameter 0.1μm to about 10 minutes, and about 100 times the current density of 10 ⁵
It is possible to generate a focused ion beam containing no metal ions of A / m ² , and it is possible to perform extremely fine processing without contaminating the sample with impurities.

Further, in the present embodiment, not only the workpiece 18 is processed by the physical impact of the focused ion beam 20, but also the secondary particles 21 emitted from the surface of the workpiece 18 due to the physical impact are processed. The secondary particle detector 17 detects as an electric signal, and CR is performed in synchronization with the scanning of the focused ion beam 20.
By subjecting the bright spot scanning on T to brightness modulation, a secondary particle image can be obtained and fine processing can be performed while observing the processing state of the workpiece 18.

The above-mentioned generation mechanism is an example for the plasma generation section, and there is no particular limitation as long as it is a generation mechanism capable of generating high-density plasma by electrodeless discharge.

As described above, the focused ion beam processing apparatus using the plasma ion source according to the first embodiment of the present invention generates a focused ion beam having a beam diameter of 0.1 μm and a current density of 10 ⁵ A / m ^2. Therefore, fine processing of wafers or devices flowing through a semiconductor manufacturing line is possible. On the other hand, a wafer or device flowing through a semiconductor manufacturing line has a multi-layered structure, and it is necessary to deeply dig down to a pattern underlying a surface in order to inspect and correct the manufacturing history of the wafer or device.

At this time, it is necessary to dig the deep hole having a large cross-sectional area having a diameter or side several times to several hundred times the diameter of the ion beam until reaching the layer to be inspected or modified. However, with an ion beam having a beam diameter of 0.1 μm and a current density of 10 ⁵ A / m ² , it takes a long time to process the large-area deep hole, and therefore the beam diameter is several times that of 0.1 μm at the same current density. Therefore, it is necessary to form an ion beam having a diameter of several tens of times. Therefore, in the focused ion beam apparatus using the plasma ion source of the present invention, a large-diameter high-density focused ion beam having a diameter several times to several tens times the beam diameter 0.1 μm without lowering the current density is provided. It also has a function to occur.

The ion beam processing apparatus using the plasma ion source is not limited to the focused ion beam processing apparatus described above, but may be a silicon wafer inspection apparatus, a secondary ion mass spectrometer, a surface foreign matter inspection apparatus, FIB
What can be easily applied to assist deposition, etc.
Needless to say.

Next, the large-diameter high-density focused ion beam forming mechanism according to the present invention will be described with reference to FIGS. 15 to 27. Here, the same components as those described in the above-mentioned plasma ion source will be denoted by the same reference numerals.

FIG. 15 shows the extraction electrode 4 shown in FIG.
FIG. 6 is a diagram showing an accelerating electrode 5 located at a distance determined by Equation 6 which is a formula of inter-electrode dielectric breakdown. At this time, the plasma state is represented by electron density Ne and electron temperature Te, the potential of the extraction electrode 4 is Ve with respect to the ground potential, and the acceleration electrode 5 has the potential of Va with respect to the ground potential. As shown in FIG. 5, the current density of the ion current that can be extracted from the plasma is determined by the electron density Ne and the electron temperature Te, and the plasma potential Vp and the plasma potential Vp at which the ion sheath is generated on the front surface of the extraction electrode 4 shown in FIG. By creating a potential difference equal to or more than the potential difference Vf of the electrode 4, it is possible to always obtain a constant ion current density. However, if D _S (seed thickness) ≧ 1 / 2D _{H 1} (drawing aperture diameter) is not satisfied, plasma spreads out between the extracting electrode 4 and the accelerating electrode 5, so that the extracting aperture diameter is simply increased. It is not possible to generate a high-density ion beam as described above.

On the other hand, as described in "Electronic / Ion Beam Handbook; 132nd Committee, Japan Society for the Promotion of Science; Nikkan Kogyo Shimbun", pages 123 to 129, when a circular hole such as an outlet exists. , And the electric field in the vicinity thereof changes the trajectories of the ions, so that the focal length of the beam moves, which causes a kind of lens action (ion lens effect).

Therefore, in order to change the beam diameter without changing the extraction port diameter, the acceleration voltage Va is adjusted and the ion lens effect near the extraction port is utilized. However, the above method defocuses the beam, and the current density is reduced. Therefore, a method of keeping the current density constant under the above conditions by increasing the output of the microwave source and increasing the plasma density to increase the electron density Ne is also conceivable. However, as shown in FIG. Since the thickness of the sheath decreases as it increases, D
_It becomes impossible to satisfy _S (thickness thickness) ≥ 1 / 2D _H1 (drawer diameter).

On the other hand, as shown in FIG. 16, even if the electron density is increased, as shown in FIG.
If the voltage between the end of the plate and the plate electrode changes, the thickness of the case changes, and the voltage between the end of the plate and the plate electrode that satisfies D _S (the case thickness) ≥ 1 / 2D _H1 (drawing port diameter) is satisfied. By applying the voltage of, the plasma can be extracted without spreading between the extraction electrode 4 and the acceleration electrode 5, and the acceleration voltage Va
Adjust, using ion lens effect near outlet, bi - beam the Deformation - Kas to ion passage of the accelerating electrode 5 diameter D _H2 less thick ion beam - makes it possible to obtain a beam. However, in the method of changing the ion beam diameter without changing the electrode structure as described above, the accelerating voltage Va changes because the beam diameter is changed.

Therefore, in the method of forming a large-diameter high-density ion beam according to the present invention, it is necessary to change the electrode structure as a method of changing the ion beam diameter without changing the acceleration voltage Va. As shown in 18, a taper is attached to the extraction port instead of the extraction electrode 4.
It is configured to use the pad lead electrode 204.

FIG. 17 shows the case where the diameter of the ion beam is set to a minute diameter used for normal processing, and FIG. 18 shows the voltage between the sheath end and the plate electrode in FIG. The state in which the electron density Ne is increased by maintaining the same is shown. In FIG. 18, compared with the state of FIG.
The thickness of the sheet decreases, and D _S (the thickness of the sheet) ≧ 1 / 2D _H1 (drawer aperture) is no longer satisfied. However, when the electron density is increased to the extent that plasma does not completely spread between the taper extraction electrode 204 and the acceleration electrode 5, the ion emission surface becomes convex in the extraction direction near the extraction port, and the ions are Since it is emitted perpendicularly to the ion emission surface,
Without using the ion lens effect near the drawer port,
The beam can be defocused. The taper outlet has an effect of preventing the ions emitted from the ion emitting surface from being erased on the side wall.

As a result, it is possible to generate an ion beam with a large diameter and a high density simply by changing the electron density Ne of the plasma.

19 and 20 show a method of changing the ion beam diameter while keeping the plasma state, the electron density Ne, the electron temperature Te constant, and the acceleration potential Va constant.
As the electrode structure, a movable extraction electrode 304 is used instead of the extraction electrode 4. That is, the movable extraction electrode 30
Numeral 4 is provided with outlets of several kinds of diameters, and the movable extraction electrode 304 is horizontally moved as necessary to retreat to a position where it does not come into contact with plasma. Can move to the axis.

Drawing port 3 in FIG. 19 for a small diameter beam
041 is moved to change the extraction port 3042 for the large-diameter beam in FIG. 20 to the ion beam axis,
The voltage between the edge of the sheath and the plate electrode is adjusted based on FIG. 7 so that DS (chassis thickness) ≧ 1/2 DH1 (drawing aperture) is satisfied. As a result, the electron density Ne indicating the plasma state, the electron temperature Te constant, and the accelerating potential Va constant,
It is possible to change the ion beam diameter.

21 and 22 show another method of changing the ion beam diameter while keeping the electron density Ne, the electron temperature Te constant, and the accelerating voltage Va constant indicating the plasma state. As the electrode structure, a porous extraction electrode 406 is used instead of the extraction electrode 4. Porous extraction electrode 406
On the upper side, the sheath surface control electrodes 404, 404 'and the insulating plates 405, 405' are provided on the central extraction ports 4061, 4062 of the porous extraction electrode 406.

As shown in FIG. 21, at the time of forming a beam with a small diameter, a voltage is applied to the sheath surface control electrode 404 so as to satisfy the condition of DS (sheath thickness) ≧ 1 / 2DH1 (drawing aperture diameter), Furthermore, the same voltage as the sheath surface control electrode 404 or less is applied to the porous extraction electrode 406,
A voltage satisfying DS (sheet thickness) ≧ 1/2 DH1 (drawing aperture) is applied. At this time, the ion emission surface is
In order to maintain the sheath thickness, the sheath surface control electrode 404 is formed in a shape conforming to the shape of the sheath surface control electrode 404. Therefore, by adjusting the voltage of the sheath surface control electrode 404, the ions are concentrated in the central extraction port 4061 of the porous extraction electrode 406 and are not extracted from the peripheral extraction port 4061 '. Therefore, an ion beam having a minute diameter is drawn out from the central outlet 4061.

On the other hand, as shown in FIG. 22, the voltage applied to the sheath surface control electrode 404 is set to DS (the sheath thickness) ≧ 1 /
Adjustment is performed while maintaining 2DH1 (drawing aperture diameter), and the voltage between the sheath end and the plate electrode is lowered until the ion emission surface becomes parallel to the porous extraction electrode 406. As a result, the extraction ports 4061 and 4 of the porous extraction electrode 406 are provided.
061 'is uniformly drawn at a constant current density,
Outlets 4061 and 406 by adjusting the acceleration voltage
By using the ion lens effect in the vicinity of 1 ', each beam is defocused and a passage diameter DH provided in the acceleration electrode 5 is provided.
A large diameter high density ion beam of 2 (= beam diameter DB) can be generated.

Next, FIGS. 23 and 24 show another method of changing the ion beam diameter by changing the electron density Ne indicating the plasma state, as in the case of using the taper extraction electrode 204. . As the electrode structure, the extraction electrode 4
A mesh electrode 505 is installed under the tape insulating spacer 506, and an acceleration electrode 5 is installed below the mesh electrode 505.

As shown in FIG. 23, at the time of forming a beam with a small diameter, ions are extracted in a state of satisfying DS (sheet thickness) ≧ 1 / 2DH1 (extraction aperture). The extracted ions are accelerated by the accelerating voltage applied to the mesh electrode 505 and become an ion beam having a minute diameter due to the passage diameter DH2 of the mesh electrode 505 smaller than the extraction diameter DH1. During the formation of the small-diameter beam, a secondary acceleration voltage is applied to the acceleration electrode 5 installed below the mesh electrode 505.

On the other hand, in FIG. 24, DS (seed thickness) <1
The electron density Ne is increased to / 2DH1 (drawing aperture diameter) to change the plasma state so that the plasma spreads between the extraction electrode 4 and the mesh electrode 505. The plasma spread along the insulating spacer 506 having a taper in the space contacts the mesh electrode 505,
The mesh electrode 505 plays a role of the extraction electrode. At this time, the mesh electrode 505 acting as the extraction electrode is applied with a voltage satisfying DS (chassis thickness) ≧ 1 / 2DH2 (extraction aperture), while the extraction electrode 4 is not applied with a voltage and floats. Leave as an electrode.

As a result, ions are extracted from the extraction port on the mesh electrode 505 which is in contact with the expanded plasma. Further, when the electron density is increased, the thickness of the sheath generated on the side wall of the taper insulating spacer and the front surface of the mesh electrode 505 is shortened, the number of extraction ports in contact with plasma is increased, and the number of extracted ion beams is increased. Will increase. At this time, the ion beam extracted from the mesh electrode 505 is applied to the accelerating electrode 5 installed below the mesh electrode 505.
A voltage is applied to accelerate the beam. Further, by defocusing by utilizing the ion lens effect in the vicinity of the outlet, the porous ion beam can be made into one thick ion beam having a large diameter and a high density.

Further, FIGS. 25 and 26 show a method of changing the ion beam diameter without changing the plasma state, the extraction voltage and the acceleration voltage. As the electrode structure, the mesh extraction electrode 604 and the movable acceleration electrode 605, and the acceleration electrode 5 are installed below the mesh extraction electrode 604 and the movable acceleration electrode 605. As shown in FIG. 25, DS (case thickness) ≧ 1/2 DH1 (drawer aperture)
The electron density Ne and the voltage between the edge of the sheath and the plate electrode satisfying the above conditions are set, and the extraction port 6041 of the mesh extraction electrode 604 is set.
Pull out the ions from. The extracted porous ion beam is uniformly accelerated by the movable accelerating electrode 605, but when forming a small diameter beam, the passage opening 6051 of the movable accelerating electrode 605 has a beam diameter DB required for forming a small diameter beam. Ions that cannot be passed though only open are eliminated on the surface of the mobile acceleration electrode 605. The mobile accelerating electrode 60
The ion beam passing through 5 is secondarily accelerated by an accelerating electrode 5 (not shown, see FIG. 22) installed below.

On the other hand, in FIG. 26, the passage opening 6052 for a large diameter, which has been retracted to the position where it does not come into contact with plasma during the fine processing of FIG. 25, is mechanically moved in the horizontal direction and installed on the ion beam shaft. It As a result, ion beams that could not pass through in FIG. 25 can pass through the mobile accelerating electrode 605, and after secondary acceleration by the accelerating electrode 5 (not shown, see FIG. 22) installed below. A large-diameter, high-density ion beam can be obtained. 25 and 26, the ion beam is defocused by utilizing the ion lens effect near the extraction port 6041.

By using the focused ion beam apparatus provided with the large-diameter high-density focused ion beam forming mechanism as described above for processing a large-area deep hole, a cross section of a wafer or device flowing through a semiconductor manufacturing line can be obtained. It becomes possible to perform observation and wiring correction at high speed.

Further, in the focused ion beam processing apparatus using the plasma ion source according to the present invention as described above, since the sample is not contaminated by the metal ions, the silicon wafer inspection apparatus or the secondary ion mass spectrometer is used. , Surface foreign matter inspection device, FIB assist deposition, etc.
Furthermore, it is possible to correct the LSI and the mask on the semiconductor manufacturing line, and the product yield can be improved. Further, even in the field of evaluation and measurement such as IMA (Ion Micro Analyzer), the SIM image of the measured object can be observed without causing contamination by metal ions. Further, it can be easily applied to an analyzer such as a secondary ion mass spectrometer.

(Example 2) In Example 2, a germanium EHD ion source (hereinafter, referred to as Ge-EHD) using germanium simple substance as an ion material as a focused ion beam generation source.
A focused ion beam device using an ion source will be described.

First, FIG. 29 shows the overall structure of the Ge-EHD ion source according to the present invention. In FIG. 29, 101 is a needle electrode (also called an emitter), 103 is a reservoir (also called a reservoir), 107 and 107 'are conducting wires (also called filaments), and 108 is an extraction electrode.

The emitter 101 is an emitter support terminal 102.
It is fixed to and is installed so as to penetrate the reservoir 103. The reservoir 103 is filled with an ionic material (germanium alone in this embodiment) 104, and has an insulating seat 105.
The filaments 107, 107 ', by the current introduced through the current introducing terminals 106, 106' fixed to the
The reservoir 103 is heated, and the germanium 104 in the reservoir 103 is melted and reaches the tip of the emitter 101. Here, by applying a negative high voltage (a power source and the like is not shown) with respect to the potential of the emitter 101 to the extraction electrode 108, the molten germanium 104 at the tip of the emitter 101 is applied.
Are released as ions 109.

The specific shape of the emitter 101 is a shaft diameter of 0.25 mm, a tip radius of 50 °, and a tip curvature radius of about 2 μ.
The reservoir 103 is in the shape of a needle having a diameter of m, and has an inner diameter of 0.7 mm, an outer diameter of 1.0 mm, and a height of 2 mm. As described in detail in the previous section, the material of the emitter and the reservoir is not the commonly used tungsten, but tungsten carbide (WC). Further, the filaments 107 and 107 'having a diameter of 0.1 mm are also made of WC. Also, the seat 105
Is made of alumina ceramic.

By setting the operating temperature (reservoir temperature) within 950 ° C. to 970 ° C., long-time operation can be expected. If the operating temperature is 1000 ° C. or higher, the ionic material is significantly vaporized, resulting in shortened life and dielectric breakdown due to adhesion to an insulator, which is not appropriate. On the contrary, at 950 ° C. or lower, germanium at the tip of the emitter is solidified, which also hinders stable ion emission.

The present ion source does not include heavy metals and dopant element ions in the primary ion beam because Ge simple substance is used as the ionic material, and the contamination of the sample surface with heavy metals and dopant elements has been removed. Since tungsten carbide is used as the material, the reaction with molten Ge is reduced, and the life is extended, which has the advantage that the time taken to replace the ion source becomes longer.

Next, an example in which one embodiment of the focused ion beam apparatus equipped with the Ge-EHD ion source is applied to a Si wafer inspection apparatus will be described with reference to FIG.

FIB device 110 having maximum acceleration voltage of 30 kV
In addition, the Ge-EHD ion source 111 according to the present invention was mounted. Reference numeral 112 denotes an emitter of the Ge-EHD ion source, 113 denotes an extraction electrode, and the FIB optical system has a beam limiting aperture 11 for limiting the spread of the ions emitted from the ion source.
4, focusing lenses 115 and 115 ′, an E × B mass separator (Wien filter) 116 in which an electric field and a magnetic field are superimposed, a diaphragm 117, a deflector 118, and the like. The Ge-FIB 121 is irradiated to the sample 120 on the sample table 119, the secondary electrons 122 emitted from the irradiation point are taken into the secondary electron detector 123, and the deflection of the Ge-FIB 121 and the scanning of the CRT (not shown) are synchronized. By doing so, a secondary electron image of the Ge-FIB121 scanning area can be drawn on the CRT.

One of the features of the second embodiment according to the present invention is that
The beam limiting aperture 114 and the aperture 117 are made of a silicon plate. This is because Ge ions emitted from the Ge-EHD ion source 111 irradiate the ion optical components, particularly the beam limiting aperture 114 and the diaphragm 117, and the secondary particles and secondary ions generated therefrom reach the sample and become a contamination source. is there. Therefore, a silicon plate was used instead of molybdenum or tungsten that has been frequently used in apertures. In addition to the silicon plate, the carbon plate and the silicon carbide plate also showed similar effects.

The Ge ion beam was focused by the FIB irradiation system having such a configuration, and the Ge ion beam was focused to 70 nm from the resolution of the secondary electron image.
It was clarified that the beam was focused to a moderate beam diameter.

Further, the sample can be sampled from the line on the wafer flowing through the manufacturing line at any time, and the valve 12
It is a configuration that can be carried in and discharged into the sample chamber 125 partitioned by 4, 124 '. Therefore, the inspection or correction can be performed in the production line, and the effect of saving the turnaround time from the inspection to the correction of the process condition is brought about.

An example of inspection using this Si wafer inspection apparatus will be described below.

The content of the inspection is to confirm whether the formation of the insulating layer between the multilayer wirings has a predetermined thickness. In order to operate the multilayer wiring structure accurately, it is an important issue that the insulating film between the wirings has a predetermined film thickness and exhibits a withstand voltage. However, in the device to be inspected, the reproducibility of the insulating film formation is poor, and since it is thinner than a predetermined film thickness, an accident occurs that causes a leak between wirings, resulting in deterioration of product yield.

Therefore, a silicon wafer that crosses the manufacturing line is randomly extracted, and Ge-FIB is irradiated to a specific portion in a predetermined inspection device on the silicon wafer, and a cross section is formed and observed. . FIG. 30 is a three-dimensional view showing how a part of the silicon wafer surface 139 is irradiated with FIB. By scanning Ge-FIB130,
A rectangular hole 131 having a side of about 5 μm and a depth of about 5 μm was formed, and a cross section of the three-layer wiring (side surface of the rectangular hole) was observed and inspected by a secondary electron image obtained by FIB irradiation.

Reference numeral 132 is a first layer wiring, 133 is a second layer wiring, 134 is a third layer wiring, 135 is a first interlayer insulating film, 1
Reference numeral 36 is a second interlayer insulating film, and 137 is a surface protective film, which insulates the first wiring 132 and the second wiring 133 from each other.
It can be observed that 33 and the third wiring 134 are vertically connected. FIG. 31 shows a state in which the insulating layer 135 between the first wiring 132 and the second wiring 132 and the second wiring 133 are focused, and particularly this portion is enlarged and observed.

Since the upper surface of the insulating layer 135 is not flat as shown in FIG. 31, a part (point A) of the second wiring 133 is B of the first wiring.
It was possible to observe that the points were close to each other, and it became clear that the breakdown voltage was lowered between AB. As a result of performing this operation for 10 inspection devices on one wafer, all points show the same tendency. Therefore, the first interlayer insulating film 13
Modifications were made to the conditions of the planarization process of No. 5. As a result of performing the same inspection after the correction of the process conditions, all the inspection points satisfy predetermined dimensions and withstand voltages, and the wafer and its lot were judged to be non-defective and passed to the next step. With such an inspection method, a defective product in the multilayer wiring formation process can be detected promptly, which greatly contributes to the improvement of the yield of the final product.

This apparatus was able to remove the emission of heavy metals and dopant element ions from the ion source by mounting a Ge-EHD ion source on the ion source of the primary ion beam irradiation system, parts in the ion optical system, In particular, it was possible to avoid impurity contamination by removing the generation of secondary particles such as heavy metals due to ion beam irradiation by using a beam limiting aperture and a silicon material for the diaphragm. Since it can be sampled from the line at any time and can be carried in and out of the sample chamber, it can be inspected in the manufacturing line, which has the effect of saving turnaround time.

In this embodiment, the primary ion beam is Ge-
Although FIB was used, Si-FIB may also be used, and Si-
A mixed beam of Si and Ge may be used with the Ge alloy as the ionic material. Also, this time, the inspection contents explained the cross-section observation of the multilayer wiring part this time, but it is not limited to this, and it may be used for forming contact holes for electron beam probing, correction by cutting the short-circuited part of the surface wiring, etc. Needless to say.

Further, in this example, since the sample was a Si wafer, a Ge-EHD ion source was used and further Ge-
The aperture of the ion beam irradiation system through which the FIB passes is S
Although the i-plate is adopted, if the sample is made of another material, the ion source and the aperture material are replaced. For example, when the sample is gallium arsenide (GaAs), a Ga-EHD ion source may be used as the ion source and an Sb plate may be used as the aperture of the ion beam irradiation system.

The ion beam processing apparatus using the above-mentioned ion source is not limited to the above-mentioned silicon wafer inspecting apparatus, but may also be used in a secondary ion mass spectrometer, surface foreign matter inspecting apparatus, FIB assist deposition, etc. It goes without saying that it can be easily summarized.

(Embodiment 3) This embodiment relates to a focused ion beam apparatus using an Ar gas field ionization ion source (hereinafter abbreviated as Ar-FIS) used as an ion source by ionizing Ar gas by field ionization. , FIG. 32 will be described.

Reference numeral 141 denotes an ion beam irradiation system, which is an Ar-F
IS 144, focusing lenses 145, 145 ′, E × B mass separator 146, aligner 147, deflector 148, gas tank 150 storing argon gas, emitter 152
The ion generating part is Ar-FIS 144, which is the greatest feature.

Argon ions ionized by the electric field by Ar-FIS 144, which is an ion source, are focused by the focusing lenses 145 and 14.
5'is focused and a high-density ion beam with a small diameter is formed.

FIG. 32 shows an example in which the focused ion beam irradiation system 141 using the Ar-FIS ion source according to the present invention is mounted on a secondary ion mass spectrometer (hereinafter referred to as SIMS) 140. The basic configuration of the secondary ion mass spectrometer 140 includes a primary ion beam irradiation system 141 having a conventional FIB optical system, a sample chamber 142, and a secondary ion analysis unit 143.

Argon ions ionized by an electric field in the ion source 144 and focused by focusing lenses 145 and 145 ′ to form a high-density ion beam with a small diameter are sample 153.
Is irradiated. Secondary ions 154 are emitted from the irradiated portion, and the secondary ions 154 are mass-analyzed by the secondary ion analyzer 143, and the composition near the sample surface can be analyzed.

In the SIMS device having the conventional FIB irradiation system, since the primary ion beam species was Ga, it was impossible to return the sample once analyzed to the semiconductor manufacturing line again from the standpoint of line contamination. There is a problem in that gallium droplets are deposited in the analysis part during the irradiation (during beam irradiation), and the analysis result becomes unreliable.

However, the Ar-FIB mounted S according to the present invention
By using the IMS, the sample surface after analysis can be returned to the manufacturing line without being contaminated with metal such as gallium, and the primary ion beam does not affect the analysis data during the analysis. Can be used as a reliable in-line analyzer. Furthermore, the analytical sensitivity is not so different from Ga-FIB.

As described above, the Ar-FIS of this embodiment is used.
SIMS, which uses a focused ion beam processing system that uses as the ion source, can sample a wafer, which is a sample flowing through the manufacturing line, from the line at any time, and can carry it into and out of the sample chamber for inspection within the manufacturing line. ,
This has the effect of saving turnaround time.

The ion beam processing apparatus using the above ion source is not limited to the SIMS described above, but may be a silicon wafer inspection apparatus, a surface foreign matter inspection apparatus, or a FI.
It goes without saying that B assist deposition and the like can be easily applied.

Example 4 Example 4 is a focused ion beam apparatus using an electrohydrodynamic Zenon ion source (hereinafter abbreviated as Xe-EHD ion source) as an ion source.

A schematic vertical cross section of the ion source according to the present invention is shown in FIG. The type of the ion source 160 is an EHD ion source, and the liquid Xe16 introduced from the supply port 167 is used.
8 is stored in the reservoir 169, and a part of it passes through the capillary 170 to reach the tip. An emitter 171 for concentrating an electric field is installed through the capillary 170. The method for maintaining the cooling of the liquid Xe 168 in the reservoir 169 is performed by supplying liquid nitrogen 1 from the supply port 172 to the cooling tank 173.
The low temperature is maintained by heat conduction of the reservoir 169 which is supplied to 74 and is coupled by sapphire 175 having good heat conductivity. The liquid Xe 168 reaches the emitter 171, and the high electric field formed by the extraction electrode 176 causes the emitter 1 to move.
At the tip of 71, it is ionized in the EHD mode and ionized, and then focused by the focused ion beam irradiation system 161 to form an ion beam.

Next, a surface foreign matter removing device for a microscopic portion, which is equipped with a focused ion beam device using the above Xe-EHD ion source according to the present invention, will be described.

Although the cleaning technology in the recent semiconductor device manufacturing has become sophisticated, it is difficult to completely remove fine dust and the like, and it is unavoidable that defective devices are generated by mixing them. In particular, if the mixed fine dust is in the insulating layer or spans between the wirings, it will cause a fatal hindrance to the device operation. In particular, with respect to a device such as a ULSI built in a super-large computer, which has a very high unit price because it is manufactured as a single item, the above-mentioned wiring short circuit due to fine dust is never allowed. Therefore, there has been a demand for a correction device which can promptly find such defects and deal with them on the spot.

The surface foreign matter removing apparatus equipped with the focused ion beam apparatus using the Xe-EHD ion source shown in this embodiment adheres to the surface by the wafer surface foreign matter inspecting apparatus after the completion of each process such as etching and film formation. It is an apparatus that detects minute foreign matter and removes fine dust by performing sputter etching of a specific region by Xe-FIB irradiation, especially for foreign matter that is difficult to remove by the conventional method.

FIG. 33 (a) is a schematic cross-sectional view of the surface foreign matter removing device as viewed from above. 160 is an ion source,
161 is a focused ion beam irradiation system, 162 is a sample, 16
3 is a secondary electron detector. The sample table 164 can be carried in and out from the device manufacturing line at any time via the valve 165. The sample 162 is irradiated with the Xe-FIB 166 focused by the focused ion beam irradiation system 161.

Next, a case will be described in which a Si-ULSI mounted on an ultra-large computer is used as a sample in the above apparatus.

FIG. 34 (a) is an enlarged view of a portion where the foreign matter 182 is attached to the wirings 181 and 181 'on the surface of the wafer 180. In this sample, the wires 181 and 181 'were short-circuited because the foreign material 182 was conductive.

In order to remove foreign matter, first, the surface of the sample is observed by a surface foreign matter inspecting device (not shown), and when a foreign matter is found, its accurate position information is stored, and the accurate position information is stored. Put in the surface foreign matter removing device. The foreign matter can be moved to the ion beam irradiation position by automatically controlling the sample stage. Next, low current Xe-FIB183
Is irradiated to a region slightly wider than the foreign matter, and the surface of the sample is observed by the secondary electrons emitted at this time to confirm the foreign matter 182. At this time, the foreign matter 182 was spherical with a diameter of about 1 μm. Increasing the sample current of Xe-FIB183 to prevent foreign matter 182
The area covered was scanned. By irradiation for about 10 minutes, although the irradiation trace 184 due to the FIB irradiation is slightly left on the sample surface as shown in FIG. 34B, the foreign matter can be completely removed.
The short circuit between the wirings 181 and 181 'disappeared, and the breakdown voltage between both wirings was restored.

This FIB is a kind of inert gas, Xe
Therefore, the greatest advantage is that the sample surface is not contaminated by FIB irradiation.

The ion beam processing apparatus using the above plasma ion source is not limited to the above-mentioned foreign matter removing apparatus, but it is also possible to remove a thin oxide film formed on the surface, and a scanning electron microscope is used. It can also be used for observation with a clear contrast when observing the surface with FIB. Further, it goes without saying that it can be easily applied to a focused ion beam processing device, a silicon wafer inspection device, a secondary ion mass spectrometer, an FIB assist deposition, and the like.

(Embodiment 5) The ion source of this embodiment has basically the same structure as the Ge-LMIS shown in Embodiment 2, but is different in that a simple substance of Si is used as an ion species. That is, in this embodiment, Si-LMI is used as the ion source.
S was adopted. Molten Si is very active, and has a problem that it reacts extremely quickly with tungsten which is a conventional emitter material, damages the emitter, and stops ion emission in a short time. And by adopting tungsten carbide for the reservoir, molten S
By reducing the reaction with i, a long time operation of cumulative 500 hours or more was realized.

An example in which the Si-LMIS ion source according to this example is applied to a minute film forming apparatus using a focused ion beam, so-called FIB assisted deposition (hereinafter abbreviated as FIBAD) will be described below.

In this example, Si-FIB was formed by using LMIS whose ionic material is Si alone.
A combination of IB and an organometallic gas was sprayed with an organometallic gas around the irradiation point of the FIB, and a tungsten (W) wiring was formed by the reaction between the FIB and the gas.

A well-known example of FIBAD is hexacarbonyltungsten (W (CO) ₆ ) gas and Ga-F as a wiring debug for a near-complete semiconductor device.
There is an example of depositing W wiring using IB. In other words, this is a so-called wiring correction method, in which wiring is reconnected to a device that does not perform the desired operation due to a partial failure due to a circuit design error or the like among devices that have been created through a predetermined process. In the debugging until FIBAD was applied, a new photomask mask was recreated and re-created through the same process again, so it takes more than a month to debug once, and it takes a lot of time to complete. Needed a cost. On the other hand, when FIBAD is used, since only the defective portion is corrected, the correction only requires several hours, which brings about a great reduction in time and cost.

However, the conventional FIBAD has had a fatal problem. That is, the modified device has a short operational life. The cause was that metal was deposited on the new wiring using organometallic gas and Ga-FIB at the time of debugging, so at this time, Ga adheres to the device surface, and this acts as an acceptor for Si, so that it is electrically connected for a long time. This is because it caused deterioration. That is, there was a problem with the primary ion beam species.

Therefore, in place of the conventional Ga-LMIS,
The Si-LMIS described in the second embodiment was used. Si
Since has the same element as the substrate, it has the greatest advantage of not being electrically contaminated. In the past, in order to release Si ions from LMIS, it was possible to obtain Si ions with a low melting point by using an Au—Si alloy, and therefore, it has been widely used. However, in this method, since Au is contained in the ionic material, Au scattered by thermal evaporation or the like was a heavy metal contamination source for the Si device process.

Therefore, in this embodiment, S is used as the ionic material.
i alone is adopted. Molten Si is very active and reacts very quickly with conventional emitter material tungsten,
Although there is a problem that the emitter is damaged and the ion emission is stopped in a short time, in this embodiment, by adopting tungsten carbide for the emitter and the reservoir, the reaction with the molten Si is reduced, and the cumulative 500 times. Realized a long-time operation of more than an hour.

Actually, W wiring by Si-FIB was performed to debug the Si device. Comparing the deposition efficiency of W, it was about the same as that of the conventional Ga-FIB. Furthermore, comparing the lifespans of the Ga-FIB modified devices, the Si-FIB modified devices continue to operate without problems even after about three years have passed since the conventional G
It has been found to have a lifetime that is at least about three times greater than the a-FIB modified device. In other words, the FIB species does not work as a dopant, so that the device is not electrically contaminated.

By using the apparatus of this embodiment, heavy metal contamination does not occur, and since the FIB species does not work as a dopant, the device modification that has been performed outside the manufacturing line can be performed inside the manufacturing line. In addition, the time required to complete the device was shortened, and the service life of the modified device could be extended.

Here, the modification of the patterned device which is almost completed is described, but the same operation can be performed on the silicon wafer.

Regarding Si-LMIS, the same effect was exhibited even when silicon carbide or silicon nitride was used as the emitter and the reservoir material.

The embodiments of the focused ion beam apparatus using the ion source which does not contain the substance contaminating the sample according to the present invention as the ion species and the apparatus using the focused ion beam apparatus have been described above. The device using the focused ion beam device is not limited to the above-mentioned embodiment.

As an example thereof, a method of inspecting / correcting a semiconductor element by using the focused ion beam apparatus having the ion source which does not cause the contamination of the semiconductor described in the first to fifth embodiments will be described.

In FIG. 35, in the middle of the semiconductor element manufacturing process, a cross section of a place to be inspected on a wafer is created by a non-contaminating FIB processing apparatus, and the cross section is observed and inspected by SEM. A method is shown in which the wafer is returned to the process and completed, a probe inspection (P inspection) is performed, and if the inspection result of the cross-sectional observation is defective, it is discarded. As a result, one of many chips formed on the wafer for inspection
You can use all the remaining chips just by crushing them. If it is found to be defective, it can be discarded to save unnecessary man-hours and materials generated in the subsequent steps.

FIG. 36 shows a flow of the wiring layer forming process of the multilayer wiring semiconductor element. A visual inspection is performed each time a wiring layer is formed, and if there is a foreign substance or a short-circuit defect, it is corrected by processing with a non-contaminating FIB and then returned to the next wiring layer forming step. Repeat for the number of layers. As a result, as shown in FIGS. 3 and 4, a high chip yield can be secured even if the chip area is increased or the wiring is multilayered.

The above embodiments 1 to 5 are merely a few examples of the present invention. The gist of the present invention is to provide a focused ion beam device that suppresses contamination of a sample by a primary ion beam species, a processing, inspection, or correction method using the focused ion beam device, and an apparatus therefor. It is well known that the number and arrangement of optical components such as deflectors can be modified in various ways from the viewpoints of beam focusing property and increase of sample current.

Also, the combination of the type of ion source and the primary ion beam irradiation system is not limited to the combination shown in this embodiment, and other combinations may be used as long as they are acceptable in terms of processing efficiency, analytical sensitivity, and the like. Needless to say.

In this example, silicon LS is used as a sample.
However, the present invention is not limited to this, but can be applied to other electronic circuit devices and modules.

[0177]

According to the present invention, a liquid metal ion source using germanium or silicon alone or an alloy thereof as an ionic material, or an inert gas species, particularly neon, krypton, argon, zenone or nitrogen as an ionic material. Focused plasma ion source, electric field ionization gas ion source and EHD
The following effects can be obtained by the processing apparatus using the focused ion beam having the ion source as the ion source.

A sample such as a silicon wafer or a silicon device can be irradiated with an ion beam without contamination of heavy metals, dopants, etc. by the ion beam species.

In the primary ion beam irradiation system of the apparatus using the above focused ion beam, the parts which are directly irradiated by the ion beam are made of silicon, germanium simple substance, or their carbides and nitrides, It is possible to significantly reduce the generation of secondary contaminants when forming the focused ion beam.

In the silicon semiconductor process, a wafer inspection apparatus, a secondary ion mass spectrometry apparatus, a wiring correction apparatus, a transmission electron microscope sample preparation capable of in-line fine processing of silicon wafers and devices, compositional analysis of local regions, etc. A device can be provided.

Since the silicon wafer or device itself and the history of the manufacturing process can be inspected in the silicon semiconductor process line, repair of defective parts and change of manufacturing process conditions can be immediately dealt with, and the turn from defect detection to response can be performed. Around time is greatly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a processing apparatus using a focused ion beam using a microwave discharge plasma with a semi-coaxial cavity resonator according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a cross-section processing of a semiconductor element by a conventional Ga-FIB and an SEM observation method.

FIG. 3 is a graph showing the relationship between the chip area and the yield of each layer.

FIG. 4 is a graph showing the relationship between the number of wiring layers and the chip yield.

FIG. 5 is a diagram showing the electron density and electron temperature dependence of the ion saturation current density of collisionless plasma.

FIG. 6 is a diagram showing the electron density and electron temperature dependence of the Debye length of collisionless plasma.

FIG. 7 is a diagram showing the dependence of the ion sheath thickness of collision-free plasma on the voltage between the sheath end and the plate electrode.

FIG. 8 is a diagram showing an ion extraction electrode structure in a conventional focused ion beam processing apparatus using plasma.

FIG. 9 is a principle diagram of an ion extraction mechanism in a conventional focused ion beam processing apparatus using plasma.

FIG. 10 is a principle diagram of an ion extraction mechanism according to the first embodiment of the present invention.

FIG. 11 is a principle diagram of an ion extraction mechanism using an ion sheath control electrode according to the first embodiment of the present invention.

FIG. 12 is a principle diagram of an electron beam / magnetic field focusing mechanism for a focused ion beam according to the first embodiment of the present invention.

13 is a sectional view taken along the line AA ′ of the electron beam / magnetic field focusing mechanism in FIG.

14 is a cross-sectional view taken along the line AA ′ of the electron beam / magnetic field focusing mechanism in the case of using the dipole magnetic field in FIG.

FIG. 15 is a principle diagram of ion extraction during microfabrication in Example 1 of the present invention.

FIG. 16 is a principle diagram of ion extraction during rough processing (large area deep hole processing) in Example 1 of the present invention.

FIG. 17 is a principle diagram of ion extraction at the time of fine processing using the taper extraction electrode in Example 1 of the present invention.

FIG. 18 is a principle diagram of ion extraction during rough processing (large area deep hole processing) using the taper extraction electrode according to the first embodiment of the present invention.

FIG. 19 is a principle diagram of ion extraction during microfabrication using the movable extraction electrode according to the first embodiment of the present invention.

FIG. 20 is a principle diagram of ion extraction during rough processing (large area deep hole processing) using the movable extraction electrode according to the first embodiment of the present invention.

FIG. 21 is a principle diagram of ion extraction during microfabrication using the porous extraction electrode in Example 1 of the present invention.

FIG. 22 is a principle diagram of ion extraction during rough processing (large area deep hole processing) using the porous extraction electrode in Example 1 of the present invention.

FIG. 23 is a taper insulating space in Embodiment 1 of the present invention.
It is a principle diagram of ion extraction at the time of microfabrication using a mesh and a mesh electrode.

FIG. 24 is a taper insulating space in Embodiment 1 of the present invention.
Roughing (large-area deep hole processing) using the sa and mesh electrodes
It is a principle diagram of ion extraction at the time.

FIG. 25 is a principle diagram of ion extraction at the time of fine processing using the mesh extraction electrode and the movable acceleration electrode in Example 1 of the present invention.

FIG. 26 is a principle diagram of ion extraction during rough processing (large area deep hole processing) using the mesh extraction electrode and the movable acceleration electrode according to the first embodiment of the present invention.

FIG. 27 is a diagram showing the dependence of the thickness of the ion sheath of collisionless plasma on the electron density of plasma.

FIG. 28 is a schematic configuration diagram for explaining a silicon wafer inspection apparatus equipped with a germanium liquid metal ion source according to Example 2 of the present invention.

29 is a schematic configuration diagram for explaining a germanium liquid metal ion source mounted on the silicon wafer inspection apparatus shown in FIG. 28.

FIG. 30 is a diagram showing how rectangular holes are formed on a wafer by a germanium focused ion beam in order to show the effect of the silicon wafer inspection apparatus according to the present invention.

31 is an enlarged cross-sectional view of the cross-section in FIG. 30, and is a diagram for explaining the cause of the inter-wiring withstand voltage defect found by the wafer inspection apparatus according to the present invention.

FIG. 32 is a schematic configuration diagram for explaining an inline secondary ion mass spectrometer equipped with an argon electric field ionization gas ion source according to a third embodiment of the present invention.

FIG. 33 (a) is Zenon E in Example 4 of the present invention.
FIG. 3 is a schematic cross-sectional view for explaining a surface foreign matter removing device equipped with an HD ion source, and (b) a Zenon EHD ion source used in (a).

FIG. 34 (a) is a diagram showing foreign matter adhering to the device surface, which was noted for explaining the effect of the surface foreign matter remover in Example 4 of the present invention, and FIG. 34 (b) is an effect of the surface foreign matter remover. FIG. 6 is a diagram showing a state after foreign matter is removed by a Zenon focused ion beam in order to show

FIG. 35 is an explanatory diagram showing a method of non-contaminating FIB cross-section processing and SEM observation in a semiconductor device manufacturing process according to the present invention.

FIG. 36 is an explanatory diagram showing a defect repairing method in a wiring process by non-contaminating FIB processing according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Microwave incidence coaxial line 2 ... 1/4 wavelength resonance type semi-coaxial cavity resonator 4 ... Extraction electrode 5 ... Accelerating electrode 6 ... Reference electrode 8 ... Plasma 9 ... Magnetic field generator 11 ... Excitation coil 12 ... Focusing electron emission Source 18 ... Workpiece 20 ... Focused ion beam 22 ... Ion sheath 23 ... Ion 24 ... Ion sheath control electrode 26 ... Electron beam 27 ... Electron beam focusing region 28 ... Conventional extraction electrode 101, 112, 152, 167, 171, ... Emitter 102 ... Emitter support terminal 103, 165, 169 ... Reservoir 104 ... Ion material 105 ... Insulating seat 106, 10
6 '... current introduction terminal 107, 107' ... filament 108, 11
3, 176 ... Extraction electrode 109 ... Ion 110 ... FIB
Apparatus 111 ... Germanium liquid metal ion source 114 ... Beam limiting aperture 115, 115 ', 145, 145' ... Focusing lens 116, 146 ... ExB mass separator 117 ...
Apertures 118, 148 ... Deflector 119,
164 ... Sample stand 120, 162, 168, 173 ... Sample 121, 130 ... Germanium focused ion beam 122 ... Secondary electron 123, 6
3 ... Secondary electron detectors 124, 124 ', 149, 149', 165 ... Valves 125, 142 ... Sample chamber 131 ... Rectangular hole 132 ... First layer wiring 133 ... Second layer wiring 134 ... Third layer wiring 135 ... First interlayer insulating film 136 ... Second interlayer insulating film 137 ... Surface protective film 140 ... Secondary ion mass spectrometer 141 ... Primary ion beam irradiation system 143 ... Secondary ion analyzer 144 ... Argon gas field ionization ion source 147 ... Aligner 150 ... Gas tank 151 ... Cooling means 160 ... Ion source 161 ... Focused ion beam irradiation system 166, 183 ... Zenon focused ion beam 167, 1
72 ... Supply port 168 ... Liquid Zenon 170 ... Capillary 173 ... Cooling tank 174 ... Liquid nitrogen 175 ... Sapphire 180 ... Wafer 181, 8
1 '... wiring 182 ... foreign substance 184 ... irradiation mark 204 ... taper extraction electrode 304 ... movable extraction electrode 406 ... porous extraction electrode 505 ... mesh electrode 506 ... taper insulation spacer 604 ... mesh extraction electrode 605 ... Mobile accelerating electrode

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location H01L 21/265 (72) Inventor Yuichi Masho 1-280 Higashikoigakubo, Kokubunji City, Tokyo Hitachi (72) Inventor Fumiwa Ito, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd.Production Technology Research Institute, Hitachi, Ltd. (72) Inventor, Yuichi Hamamura, 292, Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Manufacturing Engineering Laboratory (72) Inventor Junzo Higashi, 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Stock Company Hitachi Production Engineering Laboratory (72) Inventor Akira Shimase, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa (72) Inventor, Takashi Uemura, Hitachi, Ltd. Company Hitachi Production Engineering in the Institute

Claims (35)

[Claims] 1. An ion beam that does not affect the electrical characteristics of a sample to be treated is generated, the generated ion is focused to form an ion beam, and the formed ion beam is irradiated to the sample. Then, the sample is processed without impairing the electrical characteristics of the sample, which is a processing method using a focused ion beam generating means. 2. The processing method using a focused ion beam generating means according to claim 1, wherein the ions are generated by plasma using an inert gas such as argon, krypton, or zenon, or a nitrogen gas. . 3. The processing method using a focused ion beam generating means according to claim 2, wherein the plasma is generated by an electrodeless discharge using microwaves. 4. The ion beam to be formed is formed into a desired diameter according to the processing without lowering the current density of the ion beam, and the sample is formed using the ion beam formed into the desired diameter. Processing is carried out.
A processing method using the focused ion beam generating means described. 5. The focusing according to claim 1, wherein the sample is a silicon wafer or a silicon device, and the ions are any one of silicon simple substance, germanium simple substance, and silicon / germanium alloy as an ionic material. A processing method using an ion beam generating means. 6. A processing apparatus using a focused ion beam generating means for irradiating a sample with a focused ion beam to process the sample, wherein ions are generated that do not affect the electrical characteristics of the sample. A plasma ion source, and an ion beam forming means for extracting the ions from the plasma generated by the plasma ion source to form an ion beam,
An ion beam focusing means for focusing the formed ion beam, an irradiation means for irradiating the sample with the focused ion beam, and a sample chamber for setting the sample to be processed by the irradiation. A processing apparatus using a focused ion beam generating means. 7. The focused ion beam generating means according to claim 6, wherein the plasma ion source generates plasma by an electrodeless discharge using an inert gas such as argon, krypton, or zenon, or a nitrogen gas. A processing device using. 8. A plasma generation source for generating plasma by electrodeless discharge in a magnetic field using a microwave generation unit having microwave power supply means and microwaves resonated by the resonance unit. 7. The processing apparatus using the focused ion beam generating means according to claim 6, further comprising: 9. The ion beam forming means extracts an ion from a plasma generated by the plasma ion source in a beam shape, and an ion focusing means for focusing the extracted ion and accelerating the focused ion. A processing device using the focused ion beam generating means according to claim 6, further comprising: an acceleration unit. 10. The ion extraction unit has an extraction electrode having an ion extraction port for allowing the extracted ions to pass therethrough, and an ion sheet for controlling an ion sequence around the ion extraction port of plasma generated by the plasma ion source. 10. A scanning control electrode is provided.
A processing apparatus using the focused ion beam generating means described. 11. The ion extraction port of the extraction electrode is
Ion shield of plasma generated by the plasma ion source
11. The processing apparatus using the focused ion beam generating means according to claim 10, wherein the opening has a radius smaller than the thickness of the ion beam. 12. The ion focusing / accelerating unit includes an accelerating electrode for accelerating ions, an electron emission source located between the accelerating electrode and the ion extracting unit for emitting electrons, and an ion extracting port for the ion extracting port. A magnetic field generating source that forms a magnetic field parallel to the axial direction of the opening in the vicinity of the acceleration electrode side, and irradiates the ions extracted from the ion extraction port with the emitted electrons in the magnetic field. 10. The processing apparatus using the focused ion beam generating means according to claim 9, wherein the space charge effect on the ions is suppressed near the ion extraction port, and the radial diffusion of the ion beam is suppressed. . 13. A processing apparatus using a focused ion beam generating means for irradiating a sample with a focused ion beam to process the sample, wherein the electrical characteristics of the sample are affected even when the sample is irradiated. A plasma ion source for generating ions that do not extend, and an ion beam forming means having a beam diameter changing means for extracting the ions from the plasma generated by the plasma ion source to form an ion beam having a desired diameter, An ion beam focusing means for focusing the formed ion beam, an irradiation means for irradiating the sample with the focused ion beam, and a sample chamber for setting the sample to be processed by the irradiation. A processing apparatus using a focused ion beam generating means. 14. The plasma ion source includes a microwave generator having microwave power supply means, and a plasma generator that generates plasma by electrodeless discharge by the microwave resonated by the resonator. 14. A processing apparatus using the focused ion beam generating means according to claim 13. 15. The ion beam forming means extracts an ion from the plasma generated by the plasma ion source in a beam shape, and an ion focusing unit for focusing the extracted ion and accelerating the focused ion.
14. The processing apparatus using the focused ion beam generating means according to claim 13, further comprising an accelerating unit. 16. The ion extraction unit has an extraction electrode having an ion extraction port for allowing the extracted ions to pass therethrough, and an ion sheet for controlling an ion sheath around the ion extraction port of plasma generated by the plasma ion source. A control electrode is provided.
A processing apparatus using the focused ion beam generating means described in 5. 17. An extraction electrode having an extraction port through which the extracted ions pass, and an ion sheath for controlling an ion sheath around the ion extraction port of plasma generated by the plasma ion source. The beam diameter changing means is composed of extraction electrode voltage control means for controlling the voltage applied to the extraction electrode, and the extraction electrode voltage control means controls the voltage applied to the extraction electrode. By changing the thickness of the ion sheath of the plasma,
16. The processing apparatus using the focused ion beam generating means according to claim 15, wherein the diameter of the ion beam is changed. 18. The processing apparatus using the focused ion beam generating means according to claim 15, wherein the beam diameter changing means is constituted by the ion extraction port of the extraction electrode formed in a tapered shape. . 19. The beam diameter changing means is constituted by the extraction electrode having a plurality of openings having different diameters, and the beam is changed from a predetermined opening among the plurality of openings having different diameters according to a desired beam diameter. The processing apparatus using the focused ion beam generating means according to claim 15, wherein an ion beam is extracted. 20. The beam diameter changing means is arranged so that a predetermined opening of the plurality of openings having different diameters according to the desired beam diameter is located at a predetermined position for extracting the ion beam from the plasma. 16. The processing apparatus using the focused ion beam generating means according to claim 15, wherein the processing device is composed of an extraction electrode having a moving mechanism for moving the extraction electrode. 21. The beam diameter changing means comprises an extraction electrode having a plurality of openings, and a sheath surface control electrode installed on the plasma side of the plurality of openings via an insulating plate, The processing apparatus using the focused ion beam generating means according to claim 15, wherein the ion beam is set to a predetermined diameter by controlling the voltage applied to the sheath surface control electrode. 22. An insulating spacer, wherein the beam diameter changing means has a taper-shaped opening connected to the extraction port on the side of the extraction electrode opposite to the plasma ion source.
A mesh electrode provided on the opposite side of the insulating spacer from the plasma ion source to the tapered opening having a diameter larger than the extraction opening, and a plurality of openings having a diameter smaller than the diameter of the extraction opening. By changing the density of the plasma by controlling the voltage applied to the mesh electrode, which is constituted by the extraction electrode, and the microwave power supply means which controls the microwave power applied to the microwave generator. The processing apparatus using the focused ion beam generating means according to claim 15, wherein the ion beam is set to have a predetermined diameter. 23. In the beam diameter changing means, the ion extraction part has a plurality of openings different from the ion extraction part composed of a mesh-shaped extraction electrode having a large number of openings on the side in contact with the plasma. The ion focusing / accelerating unit configured to be movable so that a desired opening of the plurality of different openings is located at a portion through which the ions extracted from the ion extracting unit pass. 15. A processing apparatus using the focused ion beam generating means described in 15. 24. Secondary charged particle detection means for detecting secondary charged particles emitted from the sample when the sample is irradiated with the focused ion beam, and the secondary charged particle detection means detects the charged particles. 7. The processing apparatus using the focused ion beam generating means according to claim 6, further comprising an image display means for displaying an image of the sample surface based on the secondary charged particles. 25. A processing apparatus using a focused ion beam generating means for irradiating a sample with a focused ion beam to process the sample, wherein ions are generated that do not affect the electrical characteristics of the sample. An ion source, an ion beam forming means for extracting the ions generated by the ion source to form an ion beam, an ion beam focusing means for focusing the formed ion beam, and the focused ion beam A processing apparatus using a focused ion beam generating means, comprising: an irradiation unit for irradiating a sample, and a sample chamber for setting the sample to be processed by the irradiation. 26. The part of the irradiation means that receives the focused ion beam directly is formed of a main constituent element of the sample or an element of the same group as the main constituent element in the periodic table, or the surface thereof is coated. 26. The processing apparatus using the focused ion beam generating means according to claim 25. 27. The irradiation means has a beam diaphragm for narrowing the diameter of the ion beam, and the beam diaphragm is made of silicon alone, germanium alone, or their carbides, nitrides or oxides. 26. The processing apparatus using the focused ion beam generating means according to claim 25. 28. The sample is a silicon wafer or a silicon device, and the ion source uses either germanium simple substance or silicon / germanium alloy as an ionic material, a reservoir for holding the ionic material, and the ion. A conductor wire connected to the reservoir for heating and melting the material, an emitter whose surface is wetted by the ionic material in a heated and melted state supplied from the reservoir, and an extraction electrode arranged to face the emitter. Is a electrohydrodynamic ion source that emits ions from the tip of the emitter by applying a high voltage between the emitter and the extraction electrode, the member being in contact with the molten germanium. At least said emitter is made of tungsten carbide. Processing apparatus using a focused ion beam generating means according 25. 29. The sample is a silicon wafer or a silicon device, and the ion source uses either silicon simple substance or a silicon / germanium alloy as an ionic material, and a reservoir for holding the ionic material, and the ion. A conductor wire connected to the reservoir for heating and melting the material, an emitter whose surface is wetted by the ionic material in a heated and melted state supplied from the reservoir, and an extraction electrode arranged to face the emitter. Is a electrohydrodynamic ion source that emits ions from the tip of the emitter by applying a high voltage between the emitter and the extraction electrode, the member being in contact with the molten germanium. 3. At least the emitter of the two is made of tungsten carbide. Processing apparatus using a focused ion beam generating means according. 30. The processing apparatus using the focused ion beam generating means further comprises a local gas supply means for locally supplying a CVD material gas in the vicinity of a position of the sample irradiated with the focused ion beam, 30. A thin film is formed on the sample by irradiating the focused ion beam to a desired position on the sample and supplying the CVD material gas by the local gas supply means. A processing apparatus using the focused ion beam generating means of. 31. The processing apparatus using a focused ion beam generating means according to claim 30, wherein the CVD material gas is an organometallic gas. 32. The processing apparatus using the focused ion beam generating means further comprises a silicon wafer inspecting means, and the silicon wafer inspecting means irradiates the focused ion beam by scanning the sample with the irradiating means. Secondary electron detecting means for detecting secondary electrons emitted from the sample at the time, and an image displaying a secondary electron image of the surface of the sample based on the secondary electrons detected by the secondary electron detecting means. 26. Display means for displaying an image according to the processing depth of the sample surface processed by the irradiation of the ion beam on the image display means.
A processing apparatus using the focused ion beam generating means described. 33. The ion source uses xenon (Xe) as an ionic material, a reservoir for holding the ionic material in a liquid state, and a cooling tank for cooling the ionic material to maintain a liquid state. A capillary portion provided in the reservoir and having a minute opening communicating with the reservoir, an emitter penetrating the minute opening, and an extraction electrode arranged to face the emitter, and the emitter and the extraction electrode. 26. The processing apparatus using the focused ion beam generating means according to claim 25, which is an electrohydrodynamic ion source that emits ions from the tip of the emitter by applying a high voltage between the two. 34. The processing apparatus using the focused ion beam generating means further comprises foreign matter observation / removal means, and the foreign matter observation / removal means irradiates the focused ion beam by scanning the sample with the irradiation means. Secondary electron detecting means for detecting secondary electrons emitted from the sample at the time, and an image displaying a secondary electron image of the surface of the sample based on the secondary electrons detected by the secondary electron detecting means. Display means, and removes the foreign matter by intensively irradiating the foreign matter existing on the sample surface with the ion beam based on the secondary electron image of the sample surface displayed on the image display means. 34. A processing apparatus using the focused ion beam generating means according to claim 33. 35. The ion source is an ionization field type ion source using argon gas as an ionic material, and a processing apparatus using the focused ion beam generating means is arranged to treat the sample when the sample is irradiated with the ion beam. 26. The processing apparatus using the focused ion beam generating means according to claim 25, further comprising a secondary ion mass spectrometry means for detecting and analyzing secondary ions emitted from the surface of the.