JPH01307225A - Systems for negative ion generation and substrate processing - Google Patents

Abstract

PURPOSE:To effectively generate negative ion of high purity by selectively generating or leading out atom and molecule having unpaired electron, and donating electron to this particle. CONSTITUTION:Radical species or plasma are constricted by magnetic field. The radical species are atoms or molecules having unpaired electron generated by imparting energy of light and the like to the atoms and molecules in the state of gas. The plasma is generated by a method like discharge accompanying electron collision. Radical species which are not restricted by the constriction region and have no charge and led out by utilizing diffusion or gas flow, and irradiated with electron beam from a cathode and the like. Thereby, the generation of negative ion of high purity which is highly efficient as compared with applied energy value can be generated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an ion generation method and a substrate processing method using the same, and in particular, to a method for generating highly pure negative ions by irradiating radical species with electrons. and using this,
The present invention relates to a negative ion generation method and a substrate processing method suitable for selectively ion-treating the positive potential portions of materials or molecules to be treated.

[Conventional technology]

A conventional negative ion source and method and apparatus for processing a substrate using negative ions are disclosed in Japanese Patent Laid-Open No. 62-92322 as a means for obtaining negative ions.

The interaction between microwaves and magnetic fields causes electron cyclotron resonance (hereinafter abbreviated as ECR) to generate plasma with high efficiency, and the negative ions in the plasma are applied to an electrode installed at the plasma source outlet by applying a positive potential. Measures were taken to extract it. Also, this was used for etching.

(Problems to be Solved by the Invention) The above-mentioned prior art does not take into account the concentration of negative ions in the plasma, the process of generating negative ions, and the reaction characteristics of negative ions, and as a result, There are problems in that the generation efficiency of negative ions is low and there is no gain compared to conventional substrate processing methods using positive ions.

The purpose of the present invention is to provide a means for obtaining highly efficient and highly pure negative ions by improving the disadvantages of the conventional method, and
By using this, an object of the present invention is to provide an ion processing method and apparatus with a high gain that cannot be obtained with conventional processing methods using positive ions.

[Means to solve the problem]

The above purpose is to generate radical species, which are atoms or molecules with unpaired electrons, generated by applying energy such as light to gaseous molecules or atoms, or by methods that involve electron collisions such as electric discharge. The generated plasma is confined by a magnetic field, etc., and radical species, which are uncharged particles that are not restricted in the confined region, are extracted by diffusion or gas flow. By irradiating these radicals with electrons from a cathode, etc., purity can be improved. This achieves negative ion generation means with high efficiency and high efficiency compared to the applied energy value. When negative ions are extracted from this negative ion generating part to the surface of the substrate to be processed using a mesh-like electrode or the like to which a positive potential is applied, and the substrate is processed, for example, the positive potential of the positive potential part of the part of the material to be processed or the positive potential in the molecule. For example, P-type semiconductors can be etched with high selectivity, which was difficult with conventional positive ion processing methods.
Since metals and insulating materials such as S i 02 and 5iaN can be selectively etched, an ion treatment method with effects unique to negative ion treatment is achieved.

[Effect]

Radical species generated when molecules or atoms are excited by energy are uncharged, unstable particles with unpaired electrons. When electrons are donated to this radical species, it easily becomes a negative ion because it is unstable. As a means of obtaining radicals, 1) a method of applying light radiation, heat, etc. whose main component is a wavelength that does not reach the ionization energy to gaseous molecules and atoms, 2)
There are methods involving electron collision, such as electric discharge. Of these, 1
), relatively pure radical species can be obtained, but 2
In the method (1), radical species, which are the main components of the generated particles, can be obtained more efficiently, but a large amount of positive ions are also generated. Positive ions are more stable than radical species, so even if they donate electrons, they usually reduce the amount of charge or return to a stable atom or molecule, and it is less efficient to use them to generate negative ions. bad. Further, since positive ions interact with negative ions and act as a trapping agent that takes away the charge and energy of negative ions, it is not desirable to mix them into the negative ion generation region.

Therefore, in order to efficiently generate negative ions using the plasma generated by method 2), it is necessary to form an inverted magnetic interface or mirror type magnetic field, or confine charged particles with a positive potential surface, etc. It is effective to take out radical species, which are uncharged particles that are not restricted by this confinement region, by using gas flow such as diffusion or exhaust.

When the radical species obtained in this way are irradiated with electrons emitted from a cathode etc., the purity is higher than the method of directly extracting negative ions whose concentration in the plasma is extremely low.
Moreover, negative ions are generated with extremely high efficiency.

The generated negative ions have a high probability of deactivating and returning to normal stable atoms and molecules from negative ions over time. By installing an electrode with a structure that allows particles to pass through, such as a mesh electrode with an applied potential, or by applying a positive potential to the substrate, it is possible to add a potential to draw ions toward the substrate, allowing the substrate to efficiently collect negative ions. It is processed.

Unlike conventional treatments that use positive ions as the main component, when these negative ions are used, they selectively attack parts of the surface to be treated that have a positive potential, atoms that have a positive potential in molecules, etc. It is possible to perform ion treatment efficiently or selectively on positive potential areas or areas with low electron concentration on the substrate, such as by causing a reaction, or by etching the P-type semiconductor material more efficiently than the N-type semiconductor material. become. Further, metals that are aggregates of positive ions, non-conductive materials, etc. can also be efficiently ion-treated.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic diagram of the main parts of one embodiment of a substrate processing apparatus based on the negative ion generation method of the present invention.

FIG. 2 is a schematic diagram of the main part of a conventional substrate processing apparatus that extracts negative ions from plasma. The apparatus includes a vacuum vessel consisting of a plasma and radical generation chamber 1, a negative ion generation chamber (1 in FIG. 2 also serves as a substrate processing chamber 3), and a substrate processing chamber 3.
Microwave to excite gas (microwave oscillation is omitted from the diagram)
9 waveguide 4° microwave introduction window 5, substrate holder 6 that holds the substrate 18, gas supply pipe (gas supply system not shown)
7, an exhaust port (exhaust system not shown) 8, a magnetic field coil 10 that causes electron cyclotron resonance (hereinafter abbreviated as ECR), and a grid 14 for extracting negative ions. , in addition to this, control magnetic field coils 11 and 12 . which form a reversal magnetic field or a mirror magnetic field and smooth the flow of ions toward the substrate. An electron irradiator (cathode tube) 13 is provided that donates electrons to radicals.

In other respects, the shape of the vacuum container, the voltage applied to the marks on the grid 14 and the substrate holder 6, etc. are the same. The plasma and radical generation chamber 1 has a diameter of 100 [m]φ and a length of 1.
70 [nn1 (in Figure 2, 1 and 2 are used for both purposes, so the length is 25
0 [ma+]) made of SUS, the negative ion generation chamber 2 has a diameter of 1
Made of quartz with a diameter of 00 [m]φ and a length of 80 [nnl (also used as 1 in Fig. 2), the processing chamber 3 has a diameter of 10 mm on the microwave introduction side.
0 [wm] φ, exhaust side is 250 [m] φ, different diameter length 350 [■] made of SUS, substrate holder diameter 12E1
[111]φ is made of alumina, and the microwave introduction window is made of quartz.

In the figure, 15 is the ECR plane which is the main generation part of plasma, 16
17 indicates an inverted magnetic interface serving as a plasma confinement plane, and 17 indicates a negative ion flow.

Example 1 In order to investigate the amount of negative ions produced, a Faraday cup with a diameter of 70 [m]φ was installed at the position of the substrate and substrate holder, and hydrogen Hz was supplied from the gas supply pipe 7 at a rate of 50 [m Q
/mlnl is introduced, and the inside of the processing chamber is 0.8 [
mTorr]. Further, a magnetic field of 875 [Gauss] or more that satisfies the ECR conditions is applied by the magnetic field coil 7, and a microwave of 2.45 [GHa] is applied.
300 [W] was introduced to generate and extract negative hydrogen ions. FIG. 3 shows the applied magnetic flux density distribution in the conventional method (see FIG. 2) and the present method (see FIG. 1). The experiment consisted of A) using the device of the present invention, passing current through the control magnetic field coils 11 and 12 in the opposite direction and the same direction as the magnetic field coil 10, respectively, to form a reversal magnetic field in the plasma and radical generation chamber; In the same container, a current was passed through the cathode tube to form a diverging magnetic field with magnetic lines of force directed toward the processing chamber (see the curve in FIG. 3A).

B) By using the device of the present invention and adjusting the current values of the control magnetic field coils 11 and 12 while maintaining the same current direction as in A), a mirror-shaped magnetic field distribution is formed in the plasma and radical generation chamber, and In the same container, a current was passed through the cathode tube to form a diverging magnetic field with lines of magnetic force directed toward the processing chamber (see the curve in FIG. 3B).

C) Using the device of the present invention, a current was passed only through the magnetic field coil 10 to form a diverging magnetic field, and a current was passed through the cathode tube.

D) A conventional device or a device of the present invention was used, and a diverging magnetic field was used as in C).

Cathode tubes are not used.

This was done in four ways. Figures 4 and 5 show the ion current values measured using a Faraday cup.
When the ion extraction grid potential was set to +50 [V] and the current introduced into the cathode tube 13, which is an electron irradiation device, was varied (in D, it was always O [A]).

FIG. 5 shows changes in ion current values when a current of 0.5 [A] is passed through the cathode tube 13 and the grid potential is varied. Curves A-D in the figure represent experimental conditions A) to D), respectively.
corresponds to These results show that compared to the conventional method (D), which extracts negative ions from the plasma, this method, which irradiates radicals with electrons, is more effective in generating negative ions; Rather than irradiating the plasma with electrons, the plasma is confined in a magnetic field and only the radicals that have come out from the confinement region are diffused or gas flows are irradiated with electrons. , it can be seen that the method of forming a reversal magnetic interface is superior to using a mirror type distribution.

Furthermore, it can be seen that the negative ion current increases as the amount of electron irradiation increases and as the extraction potential increases.

Example 1 A silicon wafer (
After forming a thermal oxide film with a thickness of 100 [nml] on a diameter of 100 [mmlφ], polycrystalline silicon is deposited to a thickness of 500 [nm], and arsenic, As or boron, B is added at a maximum concentration of 10 [nm].
” [atoms/Gl?], this impurity-doped polycrystalline silicon film was patterned with a resist, and polycrystalline silicon was etched using the method described in Example 1. Gas was supplied as a reactive gas. 30 [mQ/
min], and the pressure in the processing chamber 3 is 1 [mTorrl].
I exhausted it so that it was. Etching by negative ions is
Using methods A) and D) described in Example 1, the cathode tube current was set to 0.5 [A] and the grid potential was set to +50 [V]. Etching with positive ions was performed using method D) when the grid potential was set to -50 [V]. [V] (method E)). FIG. 6 shows the dependence of etching rate on impurity concentration. A in the figure.

Curves D and H show that they are based on methods A), D), and E), respectively.From these results, etching using negative ions has a lower electron concentration, unlike etching characteristics using positive ions. In other words, P-type silicon rather than N-type silicon,
It can also be seen that the higher the P-type impurity concentration, the higher the etching rate. Furthermore, it can be seen that the etching speed and characteristics of the method of the present invention are significantly higher than those of the conventional method. 0 [A]) and the grid potential, and the concentration of boron and B was 1×1019 [at
Polycrystalline silicon of oms#jl was etched. The results are shown in Figures 7 and 8. Curves A to E in the figure are method A)
~E). From these results, using negative ions is better than using positive ions (E), and the conventional method of extracting negative ions from the plasma (D)
The method of irradiating electrons to radicals is better than that (C, B, A)
but.

The etching rate of P-type silicon is high, and rather than simply irradiating electrons into the plasma (C), it is better to confine the plasma with a magnetic field and irradiate only the radicals diffused from the confined region or taken out from the gas flow. It can be seen that the etching speed increases significantly, and that the etching rate is higher in the confining magnetic field method (A) in which a reversal magnetic interface is formed than in the mirror type distribution (B). It can also be seen that the etching rate of P-type silicon increases as the amount of electron irradiation increases and as the extraction potential increases.

Moreover, since these results closely correspond to the electron irradiation dose and grid potential dependence of the negative ion flow in Example 1, negative ions were used as the etchant.

It can be seen that when the amount of negative ions is increased, the etching efficiency of positive ions is low, that is, P-type silicon having a low electron concentration is efficiently etched.

A silicon wafer (diameter 1
Using a substrate on which a thermally oxidized silicon film with a thickness of 300 [nm] was formed on the substrate (00 [nm] φ), hole silicon fluoride, SFa, was introduced through the gas supply pipe 7 as an etching gas, and the rest was as in Example 2. Silicon oxide, 5iOz under the same conditions as
The membrane was etched.

Etching rate and selectivity to polycrystalline silicon (S i O
The etching rate of x/etching rate of S i) was investigated. The results are shown in Figures 9 and 10.

The curves marked A-E in the figure correspond to the etching methods described in Examples 1 and 2, and from the results of Example 1, the etching rate of the 5iOz film increases as the amount of negative ions generated increases. It can be seen that the selectivity to Si increases.

Next, through the gas supply pipe 7', hydrogen, Hz, was
After adding 1nl of Q/ml and performing etching,
In the above E, about 1.1 times in the above A-D,
The selectivity ratio (Sift/Si) increased approximately twice. This is considered to be because Hz reacts with F', which is a generated or extracted negative ion, to generate HF- ions and HFz- ions, and efficiently etches only 5 ift. As described above, it can be seen that by supplying a gas that reacts with negative ions between the negative ion generation position and the substrate, additional desired negative ions are generated, and the processing characteristics and efficiency of the substrate can be improved.

! 1314 A silicon wafer (
A silicon thermal oxide film with a thickness of 100 [μ] is formed on a diameter of 100 [μ], and Afl is deposited on it to a thickness of 1 [μ].
Using a substrate with a resist patterned on it, chlorine and CQ z were used as etching gas.
was introduced through the gas supply pipe 7, and the AQ film was etched under the same conditions as in Example 2 except for the following. FIG. 11 shows the time dependence of the etching amount in the A-E method.

In etching (E) using positive ions, passive alumina, A (lzoa) formed on the surface of the AQ film,
There is a delay time until the etching of Q starts, but this etching delay is not seen in etching using negative ions (A-D), and the method that generates a large amount of negative ions does not allow for smooth etching. It can be seen that the progress is progressing. 12th.
Figures 13 and 14 show the etching speed (E
In , we calculated the selectivity, which is the ratio of the etching speed of AQ (after the start of etching) and the etching speed for the 5iOz film, and the etching speed when the potential of the extraction grid was varied under a constant electron irradiation amount. show.

From these results, although the etching rate of AQ using positive ions is relatively high (Fig. 12),
Although the selectivity for the membrane is low (Figure 13), in etching using negative ions, the etching rate increases as the amount of negative ions generated (Figure 12) or extracted (Figure 14) increases. It can also be seen that the selectivity is also improved (Fig. 13). Even when etching metal using negative ions, the etching characteristics are better when using negative ions than positive ions, and the characteristics and etching rate depend on the amount of negative ions reaching the substrate. It is better to irradiate the plasma with electrons than the conventional method of extracting ions, or to confine the plasma in a magnetic field and irradiate pure radical species extracted from the confinement region by diffusion or gas flow. I understand.

The substrate to be processed was a silicon wafer with a diameter of 100 [ms]φ (crystal plane (100), P-type resistivity 19Ω).
Etching was performed using method A and method E under the same conditions as in Example 2, using a substrate in which boron and B were implanted into polycrystalline silicon formed to a thickness of 500 nm on the same wafer (resistivity: 19Ω1). The amount of etching was then examined using a surface roughness meter. The results are shown in Figure 15. A, E and A' in Figure 0
, E' indicate the etching rate of polycrystalline to single-crystalline silicon, respectively. From these results, when positive ions are used, there is no difference in the etching rate of polycrystalline and single-crystalline silicon, but when negative ions are used, It can be seen that polycrystalline silicon can be selectively etched with respect to single crystal silicon by controlling the amount of negative ions by controlling the amount of electron irradiation. It can be seen that the selectivity (etching rate of polycrystalline silicon/etching rate of single crystal silicon) increases as the amount of negative ions generated increases. This is because positive chlorine ions are smaller than the interstitial distance of single-crystal silicon, so they enter the lattice and etching progresses, but negative ions have a significantly larger ionic radius than positive ions, so single-crystal silicon This is because the etching cannot proceed into the lattice. Note that the radical radius is approximately located between positive ions and negative ions, and is approximately equivalent to the interstitial distance. Therefore, when the radical species reach the substrate, single crystal silicon is etched, so if the amount of negative ions is made larger than the amount of radicals that reach the substrate, the selectivity of etching polycrystalline silicon increases. In this way, it can be seen that by utilizing the size of the radius of negative ions, selective etching can be performed even when materials are composed of the same element, due to differences in their bonding states and phase states.

A silicon wafer (crystal plane (100), resistivity 19 Ωd) with a diameter of 100 [nnlφ] was used as the substrate to be processed, and oxygen and 02 gas were supplied from the gas supply pipe to 50 [mQ
/win], the cathode tube current was 1 [A], and the grid potential was 50 [V] (-50[V] in method E during positive ion processing).
V]), and a method (method A') in which 100 [V] was applied as the substrate holder potential only in method A was also performed,
A silicon wafer was oxidized and the thickness of the oxide film formed was examined at different times. Other conditions are the same as in Example 2. The results are shown in Figure 16. In the figure, A' and A to E correspond to methods A' and A to E. These results show that the time dependence of the oxide film thickness changes almost logarithmically with respect to time for all methods, but the oxidation rate is faster in the treatment using negative ions than in the treatment using positive ions (E). A', A-D), the larger the amount of negative ions produced, the more the plasma is It is significantly faster to confine the ions in a magnetic field and then irradiate the pure radical species extracted with electrons (A, A', B), and to accelerate the negative ions reaching the substrate (A'). It can be seen that the oxidation rate increases.

Add 50 ml of nitrogen and N2 gas from the ungas supply pipe in the cage.
m Q 7ml 1nl introduced, other conditions same as Example 6,
Silicon wafers were oxidized using the same method.

The results are shown in FIG. In nitriding, the same tendency as in oxidation is observed: it is better to use negative ions than to use positive ions, and the higher the negative ion production efficiency and the rate at which negative ions reach the substrate, the faster the nitrification rate will be. It can be seen that becomes larger.

50 methane and CH4 gas from the gas supply pipe
[m Q /win] was introduced to form a single film on a silicon wafer. Formation conditions were Methods A, D, and E.

FIG. 18 shows the dependence of the resistivity of the carbon film on the cathode lamp current.

In E using positive ions, the resistivity is 10” [Ω, (11
1 or less, and graphite is formed. on the other hand,
It can be seen that in methods A and D using negative ions, a carbon film with higher resistivity is formed, and in particular, when the electron irradiation amount is increased in method A, a film with almost the same resistivity as diamond is formed. This shows that the method with a high negative ion concentration can form a high quality film such as a diamond film with excellent properties.

Diameter 100 [ma+]φ as the main work substrate of the tine
Using a polycarbonate plate with a thickness of 1 [w+], ammonia, N ) (a gas) was supplied from the gas supply pipe to 50 [m Q 7
After the substrate was ammonia-treated for 1 minute, monosilane and 5iHa gas were introduced from the gas supply pipe 7' for 5 minutes.
A silicon nitride film of 100 [nm] was deposited on the substrate after the ammonia treatment, and the adhesion between the polycarbonate material and the silicon nitride film was examined. The ammonia treatment method was the A-E method, and the subsequent nitride film deposition was commonly the E method. For evaluation of adhesion, the wafer after film deposition was tested for accelerated deterioration up to 6 ooo [hl] in an atmosphere of 60 [° C.] and 90 [%] RH, and peeling at that time was visually observed. Electron irradiation amount at peeling start time (D.

E is always O[A]) The results of the dependence are shown in FIG.

From this result, the adhesion between polycarbonate, an organic material, and silicon nitride, an inorganic material, is better with treatment using negative ions than with treatment with positive ions (E) (A-D). In other words, the method that irradiates the plasma with electrons (C) is better than the conventional method that simply extracts negative ions from the plasma (D). The person irradiating (
A.

It can be seen that B) is significantly improved. This improvement in adhesion due to negative ions is due to the fact that ammonia negative ions NHz-
The carbonyl group of polycarbonate is raised, and as a result,
The surface is modified and its adhesion to silicon nitride increases (-C
-NHz), or.

This is because the surface concentration of (-C-O-) groups increases.

In this way, when negative ions are used, reactions can be selectively and efficiently induced in atoms in molecules that are at positive potential on the substrate, and this has a significant effect on surface modification of organic materials.

Although negative ions were not used to deposit the silicon nitride film in this example, the same effect as described above can be obtained even if the silicon nitride film is directly deposited using negative ions.

Using a device that combines the negative ion generation section of the present invention method shown in Example 1 of the U process and a conventional ECR plasma source for positive ion processing (conventional method in which the potential applied to the grid 14 is negative). Polycrystalline silicon was etched using chlorine and CQz gas as reaction gases. A schematic diagram of the main parts of the apparatus used is shown in FIG. The specifications of the plasma and radical generation section 1, electron irradiation section 2, grid 14, etc. of this device are the same as those shown in Example 1. The substrate holder 6' is installed at an angle of about 45 degrees with respect to the negative ion flow from the ion generating section 2, and rotates clockwise at a speed of 71 seconds. The substrate to be processed has a diameter of 100 [nn]φ
A thermal oxide film with a thickness of 100 nm was formed on a silicon wafer, and then polycrystalline silicon was deposited to a thickness of 500 nm, patterned with a resist, and As and B were implanted into each region on the same substrate surface. , n-type (AslX 1
0” [atoms/cn? ]) and P type (B
A substrate on which a polycrystalline region of IXlozt [atoms/aJ] was formed was used. The introduced microwave was introduced at 300 [W] into each plasma and radical generation section, and the CQz was introduced at 30 [m Q /n] through each gas supply pipe 7.
+ inl was introduced, and the pressure in the processing chamber 3 was 1 [mTorr]
I exhausted it so that it was. The magnetic field distribution for the ECR plasma source 1' was a divergent magnetic field, and the magnetic field distribution for the negative ion generation sources 1 and 2 was a D type. Also, the grids 14 and 14'
The voltages applied to are +50 [V] and -20 [V], respectively.
]. Etched under these conditions, n-type and P
The etching speed was almost constant for both the silicon mold and the silicon mold.

In this way, it can be seen that by combining treatment with negative ions and treatment with positive ions, materials with different electron concentrations or added impurities can be treated with the same efficiency.

Using a device that uses RF discharge to confine the generated plasma in an electric field and irradiates the radicals flowing out from this area with electrons using a filament to generate negative ions,
A silicon wafer on which 300 nm of iOz film was deposited was etched, and the etching rate of the 5iOz film and the selectivity to silicon (polycrystalline silicon, no impurity added) (etching rate of Sift film/etching rate of polycrystalline silicon) were investigated. Ta. FIG. 21 shows the main parts of the apparatus used for etching. The device has a diameter of 250 mmlφ.

It is made of SuS with a length of 600 [ml, and has an alternating frequency wave (13,
56[:MHz] ) voltage application electrode 19 and ground electrode 2
0, a filament 21 for electron irradiation to which a bias potential can be applied, a substrate holder 6 holding a substrate 18, and gas supply pipes 7, 7' and an exhaust port 8'. For etching, sulfur hexafluoride, SFe, is introduced at 30 [m11/ml1nl] through the gas supply pipes 7 and 7', and is evacuated through the exhaust port 8' so that the inside of the vacuum chamber becomes L [Torrl. [W] was applied. In addition, in order to smooth the gas flow, the electrodes 19 and 20 are
The one with many holes each having a diameter of 5 [mm]φ was used.

The current value passed through the filament as the amount of electron irradiation.

The results and conditions of etching with different grid potentials and substrate potentials are shown in the Method I column of Table 1. From these results, the higher the amount of electron irradiation, and the higher the potential applied to the substrate, the more negative ions It can be seen that the etching speed and selectivity are improved by drawing in the etching rate and selectivity.

In addition, considering that the selectivity ratio is less than 1 in normal adhesive active ion etching using SFa, it can be seen that etching using negative ions has better etching characteristics.

Etching was carried out using the apparatus shown in Example 11, in which a permanent magnet 22 was installed on the RF applying electrode to cause magnetron resonance (FIG. 22). Other conditions were the same as in Example 11. The etching results and conditions are shown in Table 1 in the column for method (■).

Comparing this result with the previous result, it can be seen that the accompanying magnetron resonance improves the etching rate and selectivity due to the increased amount of radical production.

Using a device that generates plasma by direct current arc discharge, confines it to the side opposite to the substrate side using an electric field, and irradiates the radicals flowing out from this area with electrons,
The if2 film was etched. Figure 23 shows the main parts of the equipment used. The device has a cathode 23 and an anode 2 at the end of the vacuum chamber.
A filament 21, to which a potential can be applied, is placed in the vacuum vessel 6, which has a gas supply system between the two electrodes.
That is, it has a substrate holder 6 (which also serves as a plasma confinement electric surface) and a substrate holder 6. Etching is performed on the electrode 23.
and 24, 1000 [V] was applied to cause discharge. The substrate used, gas flow rate, pressure, etc. were the same as in Example 11. The etching results and conditions are shown in the column ``Method'' in Table 1.

This result shows that the etching rate and selectivity improve as the amount of electron irradiation increases and the amount of negative ions increases.

A uV lamp is used to excite the LLA gas, and a device is used to irradiate the resulting radicals with electrons.
The SiO2 film was etched. Figure 24 shows the main parts of the equipment used. The device includes a vacuum container made of SuS having a quartz window 25 for UV light irradiation, a gas supply pipe 7, an exhaust port 8,
It consists of a high-pressure Hg lamp 26 for gas excitation, a filament 21 for electron irradiation to which a potential can be applied, and a substrate holder 6 for holding the substrate. For etching, after lighting the lamp,
The reaction gas was introduced through the gas supply pipe 7.

Other conditions such as substrate, gas flow rate, and pressure were the same as in Example 11.

The etching results and conditions are shown in the column of method (■) in Table 1. The fact that no etching occurs when there is no electron irradiation indicates that the etching is caused by negative ions.

A 5iOz film was etched using an apparatus that used an excimer laser to excite the gas. Figure 25 shows the main parts of the equipment used.

The apparatus basically has the same configuration as that shown in FIG. 24, but ArF excimer laser light 27 is used as excitation light, and the irradiation direction is parallel to the substrate.

The etching method was the same as in Example 14. The etching results and conditions are shown in the column ``Method'' in Table 1. Combined with the previous results, it can be seen that the use of laser light produces more radicals and improves the etching speed. It can also be seen that when the electron irradiation amount is increased, the etching rate increases in particular.

[111] The SiO2 film was etched using a device that utilized thermal irradiation or thermal dissociation to excite the gas and irradiated the resulting radicals with electrons. Figure 26 shows the main parts of the equipment used. The device includes a quartz tube 29 wrapped around a heater 28 for heating gas, a gas supply pipe 7, a vacuum vessel made of SuS having an exhaust port 8, a filament 21 to which a potential can be applied, a grid 30 for accelerating negative ions, and a It consists of a substrate holder 6 to which a voltage can be applied. Etching was carried out by introducing a reaction gas through the gas supply pipe 7 after the heater 28 was energized and the temperature of the quartz tube 28 reached 1000 ['C].

Other conditions such as substrate, gas flow rate, pressure, etc. were the same as in Example 11. The etching results and conditions are shown in the method ■ column of Table 1.
Although there is no significant difference in selectivity, it can be seen that the etching rate increases as the amount of electron irradiation increases and as the velocity of negative ions toward the substrate increases.

In Examples 11 to 16, only the etching results of the 5ift film were discussed, but there were also characteristics not seen in positive ion treatment when etching other films such as A Q and 5iaNa films. Furthermore, in the deposition of 5iOz, 5iC1 polycrystalline silicon, and amorphous silicon, improvements in density and electrical properties were observed, and the degree of improvement was more remarkable as the amount of electron irradiation increased.

As described above, according to this example, the method of irradiating the plasma with electrons is better than the conventional method of simply extracting negative ions from the plasma. This has the effect of significantly increasing the amount of negative ions produced, and the higher the negative ion concentration, the more negative ion treatment, such as positive potential materials, materials with low electron concentration, positive potential atomic parts, or , metals and insulating materials that are aggregates of positive ions can be selectively and efficiently etched or treated with negative ions.

Also, there is an effect of film formation and surface modification. Also,
When combined with positive ion treatment, it is possible to treat materials with high electron concentration and materials with low electron concentration with the same efficiency while maintaining the characteristics of positive and negative ions.

(Effects of the Invention) According to the present invention, negative ions are efficiently generated, and
Conventionally, it is possible to perform treatment that does not contain positive ions.
0 that could not be treated efficiently and with good selectivity, for example, P
type semiconductor, silicon oxide on silicon, AQ on silicon oxide, polycrystalline silicon on single crystal, etc., so it is possible to form P-type gates, emitter extraction electrodes, etc. in VLSI etc. Also, interlayer separation.

There are effects such as the easy formation of AQ wiring patterns on the edge film, and the easy formation of silicon oxide films, etc., making it possible to form high quality gate films for TPT. This has the effect of making it possible. In addition, surface modification of plastic substrates and 1. Since it is possible to deposit an inorganic material with excellent adhesion, it is possible to manufacture optical discs and the like with excellent durability. In addition, it is possible to generate highly pure negative ions, so positive ions can be generated in the gas phase.

It has the effect of controlling negative ion reactions.

In addition, in etching where the main component is radical, such as photo-excited etching, negative ions can be generated by simply installing a filament for electron irradiation between the excitation position and the substrate and creating a positive potential gradient on the substrate side. Therefore, the perpendicular incidence of the negative ions onto the substrate makes it possible to perform anisotropic etching, which was difficult in the past, and even when combined with the conventional radical etching method, it has the effect of making it possible to perform etching with excellent characteristics. be.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the main parts of a negative ion generation and substrate processing apparatus that is one form of the present invention, Figure 2 is a diagram showing the main parts of a conventional substrate processing apparatus, and Figure 3 is a diagram showing the main parts of a conventional substrate processing apparatus. Magnetic field density distribution diagrams, Figures 4 and 5 are diagrams showing the dependence of negative ion current on cathode tube current and grid voltage, Figures 6, 7, and 8.
The figures show the dependence of polycrystalline silicon etching rate on impurity concentration, cathode tube current, and grid voltage.
Figure 0 shows the cathode current dependence of the etching rate and selectivity of a 5iOz film, and Figures 11 to 14 show the time dependence of the etching amount of AQ and the cathode current dependence of the etching rate for a cathode with a selectivity of 1. Figure 15 shows the dependence of the etching rate on the cathode tube current for polycrystalline silicon and single crystal silicon. Figures 16 and 17 show the dependence of the etching rate on the cathode tube current for silicon. Figures 18 and 19 show the time dependence of oxidation and nitriding rates; Figures 18 and 19 are diagrams showing the cathode lamp current dependence of the peeling start time of a silicon nitride film deposited on polycarbonate; Figure 20 shows the time dependence of the nitridation rate; ,
FIGS. 21 to 26 are diagrams showing the main parts of a substrate processing apparatus that simultaneously performs negative ion processing. FIGS. 1... Plasma and radical generation chamber, 2... Negative ion generation chamber, 3... Processing chamber, 6... Substrate holder, 7.
7'...Gas supply pipe, 8,8'...Exhaust port, 9...
・Microwave, 10...Magnetic field coil for ECR, 11.
12... Control magnetic field coil, 13... Electron irradiator, 1
4.14'...Grid, 15...ECR surface, 16
... Reversal magnetic interface, 17... Negative ion flow, 18...
Substrate, 19... RF application electrode, 20... Earth electrode, 21... Filament, 22... Permanent magnet, 23
... cathode, 24 ... anode, 26 ... uV lamp,
27... Laser light, 28... Heater, 29... Quartz tube, A, A'... Partially reversed magnetic field distribution, B... Partially mirror type magnetic field distribution, C... Diverging magnetic field Distribution, D...Conventional method, E...Positive ion treatment, Vs...Substrate application μ
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Claims (1)

[Scope of Claims] 1. A negative ion generation method characterized by selectively generating or extracting atoms or molecules having unpaired electrons and donating electrons to the particles to generate negative ions. 2. Claim 1, characterized in that the atoms and molecules having unpaired electrons are radical species extracted from thermally or optically excited gas or plasma.
Negative ion generation method described in section. 3. The negative aspect of claim 1 or 2, wherein the atoms and molecules having unpaired electrons are extracted from high frequency and direct current discharge and plasma generated using the same. Ion generation method. 4. The atoms and molecules with unpaired electrons mentioned above are radical species that are extracted from the confined region by diffusion or gas flow when plasma generated using electron cyclotron resonance is confined by a magnetic field. A negative ion generation method according to claims 1 to 3 characterized in that: 5. Atoms and molecules with unpaired electrons mentioned above can be generated by irradiating atoms and molecules in the gas phase with light whose main component is a wavelength that does not cause ionization, or by thermal irradiation and thermal dissociation. A negative ion generation method according to claim 1 or 2 characterized by: 6. The negative ion generation system according to claim 3 or 4, characterized in that a reversal magnetic field or a mirror magnetic field is used to confine the plasma. 7. The negative ion generation system according to claim 3 or 4, characterized in that a grid to which a positive potential is applied is used to confine the plasma. 8. The negative ion generation method according to any one of claims 1 to 7, characterized in that a device for generating plasma or exciting gas is accompanied by a device for irradiating electrons. 9. Generation region of atoms and molecules with unpaired electrons, or
The negative ion generation method according to any one of claims 1 to 8, characterized in that a device having an electrode capable of applying a positive potential is used downstream of the electron irradiation section following the particle extraction region. . 10. A substrate processing method characterized by using the negative ion generation method according to claims 1 to 9. 11. Using particles mainly composed of negative ions as charged particles, selectively apply them to positive potential members, positive potential particles, positive ions, positive potential atoms, low concentration materials of electrons, or non-conductive materials on the substrate to be processed. A substrate processing method characterized by causing a reaction. 12. Claims 10 or 11, characterized in that a portion of a positive potential member, positive potential particle, positive ion, positive potential atom, or low concentration material of electrons on the substrate to be processed is selectively etched. Substrate processing method described in section. 13. Claim 10 or 1, characterized in that a non-conductive material on a substrate to be processed is selectively etched.
Substrate processing method described in item 1. 14. Claim 10 or 11, characterized in that the metal material on the substrate to be processed is selectively etched.
Substrate processing method described in section. 15. The substrate processing method according to claim 10 or 11, characterized in that a nucleophilic reaction or a substitution reaction is caused in positively potential atoms on the substrate to be processed. 16. Claims 10 and 10, characterized in that the surface of the substrate is modified by causing a nucleophilic reaction in the organic material on the substrate to be processed or in the carbonyl group or carboxyl group on the organic substrate. The substrate processing method according to item 11 or 15. 17. The substrate processing method according to claim 10 or 11, wherein the substrate material to be processed is oxidized or an oxide film is formed using negative oxygen ions. 18. A substrate processing method according to claim 10 or 11, characterized in that the substrate material to be processed is nitrided or a nitride film is formed using negative ions of nitrogen. 19. The substrate processing method according to claim 10 or 11, wherein the deposited film is formed using negative ions. 20. A substrate processing method characterized by combining processing using negative ions and processing using positive ions. 21. A substrate processing method characterized by modifying the surface of a substrate material to be processed using negative ions, and then continuously depositing a film in the same apparatus.