JPH05175176A - Fine pattern formation method - Google Patents

Abstract

(57) [Abstract] [Purpose] We propose a more efficient and versatile method for directly drawing a pattern on a substrate using an electron beam. [Structure] The substrate 12 housed in a reaction chamber 16 is irradiated with an electron beam 11 having pattern information substantially vertically. At the same time, optical means (25, 26, 2) is applied to the substrate 12 from a direction oblique to the irradiation direction of the electron beam 11.
7, 28, 29) to irradiate the light energy beam 24a. The electron beam 11 and the light energy beam 24a are provided only on the portion of the substrate 12 corresponding to the pattern information.
Causes a substance to change due to the reaction effect with.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fine pattern on a substrate, and more particularly, to a desired pattern information due to a reaction effect between an electron beam provided with required pattern information and a light energy beam. The present invention relates to a method of forming a fine pattern on a substrate by utilizing the reaction effect between the reactively excited particles in addition to the electron beam and the light energy beam to which is added.

[0002]

2. Description of the Related Art Conventionally, when a fine pattern is formed on a substrate, a resist mask or the like is usually provided on the substrate. However, a desired fine pattern can be formed by direct drawing without using such a mask. A method of forming a pattern has also been considered. For example, there is a method in which a gaseous molecule is excited by a photochemical reaction to form a reactive excited particle and a substrate is exposed to the reactive excited particle to irradiate a light pattern. On the other hand, as a fine pattern forming method using annealing, an annealing method using only an electron beam, an annealing method using only a light energy beam, and the like have been proposed.

[0003]

However, the method of irradiating a light pattern using reactively excited particles excited by plasma or reactively excited particles by a photochemical reaction is often used in comparison with electron beam drawing or the like. , Inferior in fine workability. Further, a fine pattern forming method (annealing method) using only an electron beam has a problem in terms of crystallinity and crystal uniformity of a substrate to be processed. On the other hand, when the light energy beam such as a laser beam alone is used, there are problems of grain boundaries and nonuniformity. In the case of using the electron beam alone or the light energy beam alone, there are many restrictions on the degree of freedom in setting various parameters related to pattern writing, and there is a problem in delicate adjustment during pattern writing. In view of such circumstances, the present invention proposes a new method that has not been proposed so far as a direct drawing method of a fine pattern, and aims to enrich the technology regarding the fine pattern formation. This paper proposes a method that can draw fine patterns with wider range and higher efficiency, or with more precise and finer control, while making use of the ability to directly form fine patterns by.

[0004]

In order to achieve the above object, the present invention irradiates a substrate contained in a reaction chamber with an electron beam having predetermined pattern information substantially vertically, and at the same time, by an optical means. By irradiating the light energy beam from an oblique direction with the electron beam irradiation direction,
Only on the part corresponding to the pattern information on the board,
We propose a method of direct formation of fine patterns, in which a material is changed by the reaction effect of an electron beam and a light energy beam. That is, under the interposition of the light energy beam, the degree of change of the substance between the substrate surface portion irradiated with the electron beam and the non-irradiated portion is significantly changed according to the predetermined pattern information, thereby changing the predetermined pattern. Is drawn directly on the substrate. Therefore, if the change in the substance is, for example, annealing, the light beam used in the present invention is a light energy beam. Therefore, even if the energy density of the electron beam is insufficient, the light energy beam provides a desired distribution ratio. It is possible to provide a new method of compensating for the shortage. Further, although the parameters when using the electron beam and the parameters when using the light energy beam are originally independent of each other, the present invention draws a predetermined pattern by their synergistic effect, resulting in a subtle result. Can be adjusted. In the present invention, in addition to the above-mentioned main structure, reactive excited particles composed of long-lived radicals generated at a site apart from the reaction chamber containing the substrate and transported by a transport pipe are also introduced into the reaction chamber. Then, a method is also proposed in which a substance is changed on the substrate due to a reaction effect between the electron beam or the light energy beam and the reactive excitation particles. The reactive excited particles may be those excited by an electromagnetic light wave chemical reaction between gas molecules and a light energy beam in a predetermined reduced pressure atmosphere introduced into the reaction chamber, instead of the above long-lived radicals. Also, there may be a plurality of the light energy beams introduced into the reaction chamber, and at least one of them may be the light energy beam that causes the electromagnetic light wave chemical reaction.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the apparatus configuration for carrying out one embodiment of the present invention. The electron optical system shown in the center of the drawing will be described from above. There is an electron gun 1 for supplying electrons, and below the electron gun 1 are a first diaphragm 2, an aligner 3, a first electromagnetic lens 4 and a blanking. The plate 5, the second diaphragm 6, the second electromagnetic lens 7, and the third electromagnetic lens 9 follow. A double deflection coil 8 a and a stigmator 8 b are arranged in the third electromagnetic lens 9. The electron beam emitted by such an apparatus system enters the reaction chamber 16 via the second diaphragm 10.

A reaction chamber 16 in which the substrate 12 is installed,
Since the required degree of vacuum is significantly different from the electron beam optical system described above, differential evacuation is performed by multiple evacuation systems to prevent the electron beam optical system from being contaminated by the reactive excitation particles present in the reaction chamber. However, the degree of vacuum required for electron beam scanning and control is secured.

The electron beam 11 focused by the electron beam optical system is irradiated on the substrate 12 to draw a predetermined pattern. The substrate 12 is installed on a support base 13, and the support base 13 is also configured so that the substrate temperature can be controlled by heating at a low temperature or the like as required. The support base 13 is installed on the X-Y moving mechanisms 14 and 15, and can perform precision alignment and precision movement similar to those of an ordinary electron beam drawing apparatus. Various materials in the reaction chamber 16 are composed of materials that are not corroded by the reactive excitation particles described later.

In the illustrated embodiment, the electron beam optical system performs the above-described differential evacuation through the exhaust ports 17, 18 and 19, and the reaction chamber 16 is exhausted through the exhaust port 20.
The pressure in the reaction chamber 16 is determined by the exhaust capacity from the exhaust ports 19 and 20.

On the other hand, the electric field-excited plasma, which is one of the important elements among the reactive excitation particles, is introduced through the transport tube 21. In front of the transport tube 21, a microwave of 24.5 GHz generated by magnetron oscillation is introduced into the waveguide 22a, and the quartz tube reaction part 23 is inserted in a part of the waveguide 22a. The end of the waveguide 22a is impedance-matched by a matching device 22b.
CF ₄ + O ₂ gas is supplied at 0.1 Torr through the introduction pipe 23a.
When the plasma is introduced at a pressure of about r, the generated plasma hardly spreads even when the electric power is increased, becomes a stable state, and the matching condition is not broken even when the gas flow rate changes. Therefore, if the plasma transport tube 21 is coated with Teflon, the active species generated in the discharge part can be introduced into the reaction chamber 16 at a distance of about 1 m without being significantly attenuated. In other words, in such plasma. Particularly, long-lived radicals can be introduced into the reaction chamber 16.

There has been a report on the plasma etching method itself using a long-lived radical excited by microwaves of 2.45 GHz as described above. That is, according to this method, polycrystalline silicon, Si ₃ N ₄ , SiO
Various thin films such as ₂ , Nb, W, Mo and photoresist can be etched. The condition is that the pressure of CF ₄ is 0.12.
When it is set to about Torr, Pr = P _o2 / P _CF4 is 0 to 4
To the extent. The advantage of plasma etching by this excitation method is that no electrode for discharge is required in the reaction chamber 16. Further, if O ₂ or N ₂ is used as an introduction gas in the same plasma excitation method, plasma oxidation or plasma nitridation with oxygen or nitrogen activated by plasma can be performed depending on the conditions.

In the above description, the reactive excited particles in the reaction chamber 16 are not attenuated so much even if they are generated at a distance of about 1 m, as described above.
6 is a plasma-excited so-called long-lived radical that can reach within 6. However, the means for forming the reactive excitation particles in the reaction chamber 16 is not limited to the above-mentioned excitation method. Recently, there have been many reports of reactive gas particles caused by photoexcitation reaction of infrared light, visible light, ultraviolet light, deep UV (far ultraviolet) light, and the like. In some cases, the deepUV described above is used.
With electromagnetic light waves of short wavelength from light to X-ray,
Excitation of gas phase particles can be performed by an electromagnetic light wave chemical reaction. As the photochemical reaction process, for example, Si is Cl ₂ or B.
It is known that dry etching can be performed by optically exciting the gas of r ₂ with a laser beam of 4880Å or 2570Å. Also, for GaAs and InP, CH ₃ Br
Etching is possible by the reaction of deep UV excitation light of the above gas. As described above and as will be described later with respect to the present embodiment, the present invention mainly focuses on forming a predetermined fine pattern on the substrate by the change of the substance due to the reaction effect of the light beam and the electron beam. However, the pattern forming method by electron beam drawing, which is also proposed in this example as one embodiment of the lower order thereof, which also incorporates the effect of the reactive gas particles by the electromagnetic light wave photochemical reaction, is the finding of the reports of various reactions described above. Is based on.

In the configuration of the apparatus shown in FIG. 1, the light beam 24 is a light beam for exciting a photochemical reaction. A light flux control system 25 is provided to temporally switch the light flux 24L emitted from a light source (not shown) or to spatially change the direction, position, etc. of the light flux. The light flux 24M emitted from the light flux control system 25 is introduced into the reaction chamber 16 through the reflection mirrors 26 and 27 and the light flux transmission window 28, and the reaction chamber 16
It becomes a light beam 24a that reaches the sample (substrate 12) through a flat or concave reflecting mirror 29 provided inside. The gas for photochemical reaction to be excited is introduced into the reaction chamber 16 from the gas sources 31 and 32 through the valve 30. The introduced photochemical reaction gas is in the light flux 24 and is in the portion 2 inside the reaction chamber.
In the light passage space as shown by 4b, it is subjected to photochemical excitation under a reduced pressure atmosphere. Further, the light beam 24a that is directly irradiated to the vicinity of the sample surface or the sample acts more strongly on the photochemical reaction. Especially when the sample surface is directly irradiated,
Since a local heating effect, an activation effect, an electron-hole excitation effect, and the like due to the light irradiation of the sample surface are added, a multi-element reaction mechanism is added. Of course, this luminous flux 24a is
According to the present invention, the luminous flux is so high as to have an annealing effect on the sample (substrate).

The effect of local heating and annealing is also observed in the electron beam. Select the relevant parameters such as focusing conditions and scanning conditions such as the spot size of the electron beam as appropriate and repeat the scan in the x direction at a speed faster than the thermal response time of the substrate to obtain the beam energy density per unit area. The value may be increased to a value of, and the heating or melting portion may be moved little by little in the y direction orthogonal to the scan width.

Further, regarding the light beam, at least one of the one or more light beams to be introduced is a light energy beam, so that the annealing by the electron beam and the annealing by the light energy beam are performed at the same location on the substrate. In this way, even if the energy density is insufficient to anneal only by the electron beam, it can be compensated by the light energy beam according to the desired distribution ratio. It is possible to provide an annealing method according to various process forms.

However, the change of the substance in the gist of the present invention means the evaporation in the case where the energy density is stronger than the local annealing depending on the pattern information on the substrate or the semiconductor layer on the substrate, and in some cases the energy density is stronger in the pattern portion. In that sense, it is possible to directly provide a microfabrication process. In any case, as in the prior art, when the electron beam alone or the light energy beam alone is used, there are many restrictions on the degree of freedom in setting various parameters related to pattern writing, and there are subtleties in pattern writing. In contrast to the difficulty in adjustment and the like, the present invention enables finer control.

In addition to this, a long-lived plasma radical,
Alternatively, by introducing reactive excitation particles by an electromagnetic light excitation reaction in the vicinity of the substrate, and by a reaction effect between the electron beam, the light energy beam and the reactive excitation particles, only on a portion of the substrate corresponding to desired pattern information. Can also cause changes. In this case, the patterning result varies depending on the nature of the reactive excitation particles, and an etch pattern, a plasma oxidation region pattern, a fine deposition pattern, etc. can be obtained.

It is also possible to make the light beam 24 scannable to improve the uniformity and controllability of light irradiation on the sample surface. Mechanically, the mirrors 26, 27, 29 may be driven by a minute moving mechanism. For higher speed operation, an electronic optical switch or an optical path changing device may be provided in the light flux control system 25. Also,
By using an optical switch with several polarizations, a half mirror, a microlens array, an optical fiber, etc., it is possible to process a plurality of light beams simultaneously and in parallel. As a result, each of the plurality of luminous fluxes can be independently temporally intermittently and spatially arranged. Illustrated light flux control system 25, mirrors 26, 2
The optical system such as 7, 29 is just an example. It is apparent from known existing techniques that there are various light flux group control methods in addition to this.

A plurality of light beam transmitting windows are separately provided in a structure similar to that of the electron beam pattern drawing system as shown in the figure, and a plurality of light beam groups are intermittently and spatially incident on each light beam transmitting window. You can also let it. Since the control of the luminous flux is the same in vacuum and in the atmosphere, it is possible to bring the control system for the various luminous flux groups into the reaction chamber 16. However, whether it is one or more,
It is preferable to make such a light beam incident obliquely above the substrate in the reaction chamber. Further, when a light flux control system is provided in the reaction chamber, a container for protecting the control system with a material such as a quartz plate or Teflon coat is provided so that the control system is not damaged by the reactive excitation particles. There is a need.

As described above, according to the present invention, it is possible to provide a new method of pattern annealing by the synergistic effect of the electron beam and the light energy beam.

Furthermore, according to one aspect of the present invention in which the action of the atmosphere containing the reactive excitation particles is added in addition to the synergistic effect of the electron beam and the light energy beam, the long-life radicals excited by microwave plasma are excited. Plasma treatment, photochemical treatment with photochemically reactive particles,
Furthermore, a desired pattern corresponding to predetermined pattern information can be directly formed by incorporating a process in the presence of these two kinds of reactive excitation particles together.

Regarding the oxidation process using reactively excited particles such as long-lived radicals of oxygen, the depth of the oxide layer is controlled and patterned, and the film quality is modified and patterned by pattern beam annealing after oxidation. It is also effective.

The electron beam in the present invention is, as defined in the technical field of this kind, based on electron optical engineering technology, a known existing electron beam acceleration system or deceleration system, electron beam focusing / traveling system, A literal electron beam that can be manipulated or controlled by an electron beam deflection system or an electron beam optical system. Therefore, although an apparatus system similar to a normal scanning electron beam control system is shown in FIG. 1, other known existing electron beam drawing systems such as a variable shaped beam drawing system and an appropriate condition setting are used. Any device may be used as long as it has an electron beam focusing control system similar to a known electron beam transfer system.

Further, in such an electron beam optical focusing system for controlling and driving the electron beam, the related parameters are variably controlled or changed to control the energy of the electron beam and the spatial distribution of the beam bundle. ,
Appropriate parameters can be selected, and the degree of freedom in design can be given to a certain extent to the resistless pattern direct formation technology which is an application of the present invention.

On the other hand, as the photochemical excitation beam, various laser beams in the far ultraviolet region to the infrared region can be used. As the drawing mode, for example, scanning or transfer of an electron beam is performed within one frame, and after one frame is completed, step and repeat is repeated. On the other hand, conventionally, as a pattern drawing technique using various beams such as lithography using charged particles or a light beam, by precisely moving the moving table on which the substrate is installed, it is necessary to write on the substrate in a writing manner. Although there is a technique for forming a pattern, the well-known conventional technique is also applicable to the present invention.

[0025]

According to the present invention, it is possible to form a fine pattern such as pattern annealing and pattern etching based on a new mechanism by a resistless direct process for a substrate without exposing it to the atmosphere in a vacuum exhaust system. It can be advantageously used as a part of a fine pattern direct pattern formation process, which is expected to progress. Naturally, this contributes to improvement in manufacturing efficiency and performance of various electronic devices and integrated circuits.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus configuration that can be used to carry out an embodiment of a fine pattern forming method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 electron gun, 11 electron beam, 12 substrate, 13 support stand, 14, 15 XY movement mechanism, 16 reaction chamber, 17, 18, 19 exhaust port, 20 exhaust port, 21 plasma transport tube, 22a microwave waveguide , 23 quartz reaction tube, 24 light beam, 25 light flux control system, 26, 27 reflecting mirror, 28 transmission window, 29 reflecting mirror, 31 gas source, 32 gas source.

Claims (4)

[Claims] 1. An electron beam having pattern information is irradiated substantially perpendicular to a substrate contained in a reaction chamber; at the same time, the substrate is obliquely tilted by an optical means from the direction of irradiation of the electron beam. By irradiating with the light energy beam, the substance is changed only by the reaction effect of the electron beam and the light energy beam on the portion of the substrate corresponding to the pattern information. Fine pattern forming method. 2. A substrate contained in a reaction chamber is irradiated with an electron beam having pattern information substantially perpendicularly thereto; at the same time, the substrate is obliquely tilted by an optical means from the direction of irradiation of the electron beam. On the other hand, by irradiating the substrate with a light energy beam; and by introducing into the reaction chamber, by means of a transport means, reactive excited particles composed of long-lived radicals generated at a site distant from the reaction chamber; A method for forming a fine pattern, characterized in that a substance is changed only by a portion corresponding to the pattern information due to a reaction effect of the electron beam, the light energy beam and the reactive excitation particles. 3. The method for forming a fine pattern according to claim 2, wherein the reactive excited particles are replaced with the long-lived radicals, and gas molecules are introduced into the reaction chamber in a predetermined reduced pressure atmosphere to generate the gas. A method for forming a fine pattern, which is excited by an electromagnetic light wave chemical reaction between a molecule and the light energy beam. 4. The method for forming a fine pattern according to claim 3, wherein there are a plurality of the light energy beams, and at least one of the light energy beams causing the electromagnetic light wave chemical reaction is present. And a fine pattern forming method.