JPH02207525A - Substrate processing method and apparatus therefor - Google Patents

Abstract

PURPOSE:To improve the efficiency of substrate processing and realize adequate processing characteristics by introducing light of a specified wavelength exciting interatomic combination vibration into a vessel for substrate processing, and exciting oscillation of molecule turning to substrate processing species or parent body of substrate processing species. CONSTITUTION:In a plasma etching apparatus provided with an upper and a lower facing electrodes 2, 12, a substrate is arranged on the lower electrode 2, and SF6 is introduced through a gas feeding pipe 3, which gas is discharged from an exhaust vent 4. The above substrate is constituted as follows; an oxide film is formed on a single crystal silicon substrate surface, polycrystalline silicon is deposited thereon, and a pattern is drawn by using resist material. By a high frequency power supply 6, a specified RF wave is applied to the upper electrode, and plasma is generated. At the same time, infrared rays radiated from a globar lamp 7, whose wavelength is 2.5mum or less, is collected by a reflecting mirror 8; said infrared rays are made into infrared rays 11 by a spectroscope, and are introduced in a reaction vessel 5 through a window plate 10 arranged on the side surface of the reaction vessel. Thus etching is performed. In this manner, interatomic bonding of etching gas or etchant is excited by infrared rays irradiation, thereby increasing etching rate.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to etching used in LSI manufacturing, etc.

The present invention relates to film formation and impurity addition, and particularly to a substrate processing method and apparatus suitable for improving the substrate processing efficiency and optimizing processing characteristics.

[Conventional technology]

In the conventional apparatus, as described in Japanese Patent Application Laid-Open No. 117711/1983, plasma is first generated in order to process the substrate.
In order to further decompose unreacted gas in the plasma,
There is a method that aims to improve the processing speed of substrates by irradiating them with ultraviolet rays, and a method described in JP-A-59-172237, in which near-infrared rays are irradiated from an infrared lamp to a substrate in plasma. There was a method to improve the processing efficiency of the substrate by heating it.

[Problem that the invention sought to solve]

The above-mentioned conventional technology has the following points: an unreacted or unexcited gas is brought into an electronically excited state by light (wavelength of 1 [μm] or more) to increase the number of substrate processing species;
Although consideration has been given to increasing the reaction between the substrate and the substrate treatment species by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by heating the substrate by increasing the reaction between the substrate and the substrate treatment species, increasing the concentration of the treatment species that inherently have excellent processing characteristics due to the generation mechanism of the substrate treatment species. No consideration is given to the method, and as a result, in the prior art, for example, if the etching rate is increased based on the prior art method.

There are problems in that selectivity with the base material decreases and film quality deteriorates when the deposition rate increases.

An object of the present invention is to improve the above-mentioned disadvantages.

[Means to solve the problem]

The above purpose is to add a wavelength (2.5 [μm]
This can be achieved by adding a method of introducing the above-mentioned light and vibrationally exciting the substrate processing species or the molecules that are the base of the substrate processing species.

[Effect]

Molecules formed by at least two or more atoms, or molecules produced in conventional substrate processing methods,
For particles such as radicals and ions.

Light with a wavelength corresponding to the infrared active vibration between the bonds of atoms that make up the particle (wavelength range 2.5 to 25 [25 μm])
When irradiated with , the particle transitions to a vibrationally excited state (however, the electronically excited state is a ground or metastable state).

Even if a particle in the vibrational ground state is excited or continues to be excited using the conventional method described above, there is a high probability that the electronic state will exist in a metastable state, and the dissociation of interatomic bonds will not occur in many systems. Vibrational transition v=n→v=n+1 in the particle. n+3. If there is n+4... (n is a vibrational level, n=o, 1, 2, 3-), there is a high probability of the existence of a short bond distance involved in dissociation, so based on the Franck-Conton principle, , the probability of the system reaching the dissociation energy value is high even for systems that are not suitable for substrate processing or highly efficient processing, that is, systems whose electronic state mainly transitions to a metastable state. As a result, the production efficiency of substrate processing species is significantly increased. Therefore, it is possible to process a substrate with higher efficiency than that obtained by the conventional method. In addition, by controlling the state of vibrational excitation, it is possible to highly select particles suitable for substrate processing, and to optimize this bonding and substrate processing. Quality improvement etc. can be achieved.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

Example 1 FIG. 1 is a schematic diagram of an apparatus that is one embodiment of the present invention. An oxide film is formed on the surface of a single crystal silicon substrate (diameter too [mm]) and polycrystalline silicon is deposited on it in a conventional parallel plate type plasma etching apparatus having two opposing upper and lower electrodes 2 and 12. A substrate with a pattern drawn with a resist material is placed on the lower electrode 2, a gas introduction tube 3 is obtained, SFe is introduced, and exhaust is performed at a predetermined flow rate from the exhaust port 4, and a reaction vessel 5 is formed. The internal pressure is 1 [Torr]
The high frequency power supply 6 applies 13.6 [M
An RF wave of Hzl is applied to generate plasma, and at the same time, the light emitted by the infrared light source, the global lamp 7, is collected and separated by the reflecting mirror 8, and the separated infrared light 11 is reacted. A window plate 10 made of a thallium bromide iodide material installed on the side of the container was obtained and introduced into the reaction container 5 in which substrate processing was performed, and etching was performed. RF wave power is 300 [
FIG. 2 shows the etching speed of Si when the power of the irradiation light was varied when the power of the IR light source was 400 [W], and FIG. 3 shows the etching speed of Si with respect to the power of the RF wave applied when the IR light source power was 400 [W]. In the figure, A indicates the IR light source power O [W], and B indicates the value when the IR light source power is set to 300 [W].

From FIG. 2, the etching rate increases as the IR light source power increases. In other words, it can be seen that the generation efficiency of etching species increases. From Figure 3.

When infrared light is not irradiated (A), even if the applied RF waves are increased, the etching rate does not increase above approximately 50 [W], but in infrared light irradiation (B),
It can be seen that as the RF wave power increases, the etching speed increases, that is, the generation efficiency of etching species improves. In order to investigate the factors contributing to the improvement in the generation efficiency of the etching species mentioned above, we investigated the wavelength 1 at which the S-F bond is vibrationally excited.
When only light of ° [μm] is irradiated (B'), 10 [μm]
] (C), infrared lamp light (the luminous body is placed in a glass tube 9
When the emission wavelength is irradiated in the near-infrared region (2.5 μm or less) (D), ultraviolet light (H
The case (E) was investigated when irradiated with a g lamp). 10[μm
] was used for light irradiation, and in order to remove only the 10 [μml light, the interference filter 9 was replaced with a cut filter in an experiment. When using an infrared lamp and an Hg lamp, experiments were conducted with the filter removed. The results are shown in Figure 4. The horizontal axis shows the light source power. 10[μm
It can be seen that when irradiation is performed with light having a wavelength of . From this, it was found that the main reason why the etching rate was improved by irradiation with infrared rays was that the interatomic bonds of the etching gas or etchant were excited.

Furthermore, it has been found that the method of vibrational excitation is more effective in improving substrate processing efficiency than the addition of heating or electronic excitation. Figure 5 shows the RF wave power of 3
FIG. 3 is a diagram showing the dependence of the etching rate of Si to 5iOz, that is, the selectivity, on the light source power when the etching rate is 00 [W]. It was found that only when the S-F bond was vibrationally excited, the selectivity improved as the power increased, that is, the etching characteristics improved. From this, it was found that adding vibrational excitation not only improves substrate processing efficiency but also improves substrate processing characteristics.

Embodiment 2 FIG. 6 is a sectional view of the main parts of a substrate processing apparatus which is one embodiment of the present invention. This device uses a microwave plasma method using electron cyclotron resonance to generate plasma.

Plasma generation chamber 16. A microwave waveguide 14, (the oscillator of the microwave 13 is omitted from the illustration), a magnetic field generating coil 17. Substrate processing chamber 5. Exhaust tube 49 reaction gas introduction pipes 3 and 3',
Substrate holder 2' that can apply RF waves, infrared light @7. It consists of a reflecting mirror 8, an interference filter 9' that passes wavelengths of 4 to 5 μm, and an infrared transmission window 10. A silicon wafer was used as the substrate 7 to be processed, and a silicon oxide film (SiO2) was formed thereon. A first gas introduction pipe 5 is inserted into the plasma generation chamber 16.
200 [mQ] of oxygen was introduced through the
(The microwave 13 of zl is introduced into the plasma generation chamber through the quartz window 15, and a magnetic field of 875 [Guuss] or more is generated by the magnetic field generation coil 17 to generate plasma, and the second gas 50 [mu/win] of monosilane (S i H4) was introduced from the introduction pipe 3', and the pressure in the processing chamber 5 was set to 3 [mTorrl] by the exhaust system. A film was formed by irradiating infrared light 11 with a wavelength of [μm] into the processing chamber 5.The film was etched using a buffered hydrofluoric acid solution CHF:NH4F=1:6) as the deposition rate and R degree of the density of the deposited film. (2) The dependence of the etch rate and the atomic ratio of the deposited film on the power of the IR light source measured by Auger spectroscopy is shown in FIGS. 7 to 9. From these results, the material gas S i H4
Alternatively, S i Ha, S i H2 which becomes a depositing species
゜Increasing the rate of vibrational excitation of SiH, that is, increasing the IR light source power, not only significantly increases the deposition rate but also improves the density of the deposited film and changes the stoichiometric composition (S
It was found that a film with i10z=0.5) was formed.

When the interference filter was removed and the light from the global lamp was introduced without being separated, the same results were obtained regarding the deposition rate as before, but no significant improvement in the quality of the deposited film was observed. The results are shown in FIG. 8-9 using a dashed line. This result shows that selective excitation of deposited species is necessary to improve film quality.

Example 3゜ Using an n-type (<100> plane 12 [Ω■]) silicon wafer as the substrate to be processed, B2H was supplied from the first gas introduction pipe 3.
8 was introduced at a rate of 50 [rnQ/min, and the pressure was 0,5
[mTorrl] While applying RF waves of 200 [W] to the substrate holder to promote ion injection into the substrate, doping with boron and B was performed for 30 [minutes]. The interference filter was designed to transmit light that excites the B-H bond. Other conditions are the same as in Example 2. FIG. 10 is a diagram showing the doping profile at this time, and shows 1 degree of B with respect to the depth direction of the substrate. A is the case without infrared irradiation, and B is the case with infrared irradiation. As can be seen from this figure, it was found that when the doping gas was vibrationally excited by irradiation with infrared light, the processing efficiency was significantly increased.

Example 4 Ultraviolet light was used to excite gas, and the excited species generated thereby deposited a 5iOz film on a substrate.

FIG. 11 shows the main parts of the device used, which is one form of the present invention. The device is a low pressure mercury lamp18. It has a quartz window 19 that allows ultraviolet rays 20 to pass through.

The deposition of the 5iOz film was carried out by introducing a mixed gas of tetraethoxysilane (C2H50)4si and oxygen through the gas introduction tube 3. At this time, C-0,5i-
300 [W] with a wavelength of 7 to 10 [μm] that excites the 0 bond
Infrared rays were introduced into the device. The deposition rate of the 5iOz film and the etch rate of the deposited film at this time are shown in FIG. 12.13. These results show that by combining the film deposition method using optical excitation with the method of vibrationally exciting the gas that serves as the deposition species, it is possible to improve the deposition rate and make the film significantly denser. When the infrared filter was removed and infrared light was irradiated, the deposition rate and etch rate were the same as before, but when the atomic composition of the film was examined, it was found that carbon and hydrogen were mixed in. It was done. When irradiated with spectroscopic infrared rays, no contamination of carbon or hydrogen was observed. The cause of this is (C2Ha○
) This is thought to be because the C--H bonds of aSi were also excited, so that carbon and hydrogen were liberated and were included in the deposited film. From this, it can be seen that the substrate processing characteristics can be improved by selecting the atoms to be vibrationally excited by spectrally dispersing the irradiated infrared light.

Example 5 Using thermal irradiation or thermal dissociation to excite gas, 5iC)
z film was deposited. FIG. 14 shows the main parts of the device used, which is one form of the present invention. The device has a heater source. The deposition of the 5iOz film was carried out by introducing a mixed gas of (CzH60)aSi and oxygen from the gas introduction pipe 3 in the same manner as in Example 3. Conditions such as filters are the same as in the third embodiment.

FIG. 15 shows the dependence of the deposition rate on the infrared light power.

This result shows that the deposition rate can be improved even when the vibration excitation method is combined with the thermal CVD method.

According to this embodiment, etching and doping.

When processing substrates such as film deposition, conventional substrate processing methods
It has been found that combining irradiation of substrate processing species or their parent gas molecules with infrared light that excites interatomic bonds has the effect of improving substrate processing efficiency and processing characteristics.

Furthermore, it has been found that dividing the irradiation light into spectroscopy and exciting specific interatomic bonds allows for the selection of substrate processing types, and also has the effect of improving processing characteristics.

In this example, a global lamp was used as the light source, but
Of course, the same effect can be obtained by using other infrared light emitting sources, and although a filter is used for spectroscopy, it is also possible to use a diffraction grating, a prism, etc. to perform spectroscopy.

〔Effect of the invention〕

According to the present invention, the production efficiency of substrate processing species can be improved compared to conventional substrate processing methods, which has the effect of increasing the throughput of substrate processing.Also, since the substrate processing type can be selected, substrate processing characteristics It has the effect of improving In the process of forming plasma using electrical discharge,
Although damage to the substrate increases almost in proportion to the power used for discharging, the method of the present invention allows for reduction of the discharge power, thereby providing the effect of processing the substrate with less damage.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an apparatus which is one form of the present invention, FIG.
Figures 3 and 4 show the light source power or R of etching speed.
A diagram showing F power dependence, Fig. 5 shows Si on SiO2
FIG. 6 is a diagram showing an apparatus according to an embodiment of the present invention. FIGS. 7, 8, and 9 are graphs showing the dependence of the selectivity on the power of various light sources. FIG. 7, FIG. 8, and FIG. Diagram showing the dependence of the etch rate and atomic ratio of the deposited film on the IR light source power, No. 10
Figure 11 is a diagram showing an apparatus according to one embodiment of the present invention, Figures 12 and 13 are diagrams showing the deposition rate of 5iOz film,
A diagram showing the dependence of the etch rate of the deposited film on the power of the IR light source,
FIG. 14 is a diagram showing an apparatus which is one form of the present invention, and FIG.
The figure shows the dependence of the deposition rate of the SiO2 film on the power of the IR light source. DESCRIPTION OF SYMBOLS 1... Substrate, 5... Substrate processing container, 6... RF wave oscillator, 7... Infrared light source, 9... Filter, 10...
・Infrared transmission window, 11...Infrared rays, 13...Microwave, 17...Magnetic field generating coil, 18...Low pressure Hg lamp, 21...Heater source, A...No infrared irradiation , B
...Infrared irradiation, B'...Vibrational excitation wavelength light irradiation, C.
...Vibration excitation wavelength cut, D...Infrared lamp light irradiation,
E: Ultraviolet light irradiation. No.! begging

Claims (1)

[Claims] 1. In a method of processing a substrate using excited molecules, radicals, or ions, the substrate is processed while introducing infrared light that excites interatomic bonds into a container for processing the substrate. A substrate processing method characterized by: 2. The substrate processing method according to claim 1, wherein the wavelength of the infrared light is 2.5 [μm] or more. 3. The substrate processing method according to claim 1 or 2, characterized in that in the method for processing a substrate, electric discharge is used to generate the processing species. 4. Substrate processing according to claim 1 or 2, characterized in that in the method for processing the substrate, light that provides electron energy to molecules is irradiated to generate the processing species. Method. 5. The substrate processing method according to claim 1 or 2, which utilizes applying thermal energy to molecules in order to generate processing species in the method of processing a substrate. 6. Claims 1 to 5, characterized in that the infrared light is spectrally divided and only light of a specific wavelength is introduced into the container.
Substrate processing method described in section. 7. Claims 1 to 6, characterized in that the above-mentioned substrate treatment involves etching a desired material on the substrate.
Substrate processing method described in section. 8. The substrate processing method according to any one of claims 1 to 5, wherein the substrate processing includes forming a film on the substrate. 9. The substrate processing method according to any one of claims 1 to 5, wherein the substrate processing includes adding an impurity to the substrate. 10. In an apparatus that generates plasma by electric discharge and processes a substrate with the plasma, a temperature of 2.5 [μ
1. A substrate processing apparatus characterized by introducing light having a wavelength of 100 m or more. 11.Introducing light with a wavelength of 2.5 [μm] or more into the device in which gas molecules are irradiated with light with a wavelength of 1 [μm] or less to excite them and a substrate is treated with the excited molecules. A substrate processing device featuring: 12. Excite gas molecules by giving them thermal energy,
A substrate processing apparatus for processing a substrate with the excited molecules, characterized in that light with a wavelength of 2.5 [μm] or more is introduced into the apparatus. 13. In order to introduce the above-mentioned wavelength of 2.5 [μm] or more into the device, a compound of thallium, a compound consisting of a halogen element and an element of Group 1 or Group 2 of the periodic table of atoms,
Alternatively, claims 10 to 12 are characterized in that the window is made of a material based on a zinc compound.
Substrate processing apparatus described in Section 2. 14. The substrate processing apparatus according to claims 10 to 12, wherein the light source having a wavelength of 2.5 [μm] or more is installed in a container for processing the substrate. 15. The substrate processing apparatus according to claim 10, wherein a thermal radiation type light emitter is used as a light source with a wavelength of 15, 2.5 [μm] or more. As a light source with a wavelength of 16, 2.5 [μm] or more, lasers and SOR (\S\ychromotron\O\rbi
15. The substrate processing apparatus according to claim 10, characterized in that the substrate processing apparatus uses light (tal \R\ adiation). 17. The substrate processing apparatus according to claims 10 to 16, characterized in that only light of a specific wavelength is separated out of the light having a wavelength of 2.5 [μm] or more and introduced into the apparatus. . 18. The substrate processing apparatus according to claim 17, wherein an optical interference filter and a cut filter are used for the spectroscopy. 19. The substrate processing apparatus according to claim 17, wherein a slit and a prism or a slit and a diffraction grating are used for the spectroscopy.