JP3194363B2 - Patterning method and patterning apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a patterning method and a patterning apparatus for selectively forming a fine pattern using a photochemical reaction.

[0002]

2. Description of the Related Art Integrated circuit components, which are indispensable for forming various systems for transmitting and processing a large amount of information at a high speed, require finer patterns such as wiring in order to improve the degree of integration. Is required.

[0003] Various process techniques developed for forming fine patterns are realized by combining a technique of depositing a material into an arbitrary planar shape and a technique of removing the material in a similar manner. is there. Specifically, after a mask pattern is created by a lithography technique, a material is selectively grown or removed by a lift-off method.
It is a process that consists of stages.

However, the above-described process techniques have problems such as processing damage, reduction in dimensional accuracy, and complication of the process. Therefore, as a process technology capable of forming a fine pattern without causing these problems, a vapor phase growth method using light is being studied.

For example, chemical vapor deposition (CV) in which an aluminum film is deposited using Al (CH ₃ ) ₃ as a source gas.
In D), the substrate is irradiated with an ArF laser beam through a mask on which a desired pattern is formed, and Al (CH ₃ ) ₃ is excited only in a portion irradiated with the laser beam, whereby the pattern of the mask is formed on the substrate. The aluminum film can be selectively deposited according to the conditions.

[0006]

However, the method of selectively growing or removing a material using light has a problem in that a pattern whose size is less than the wavelength of drawing light cannot be formed. This is because the processing accuracy is limited by the diffraction limit of light. In addition, since a mask is used, there is a problem in that it is difficult to change the shape of a pattern during film formation or to continuously change the shape in a film thickness direction.

The present invention has been made to solve such a problem, and the processing accuracy is not limited by the wavelength of drawing light, and a mask is used to form a pattern of an arbitrary shape. It is an object of the present invention to provide a patterning method and a patterning device that do not need to be used.

[0008]

According to a patterning method of the present invention proposed to solve the above-mentioned problems, a patterning method for forming a pattern of an arbitrary shape on a material surface comprises the steps of: A source gas adsorption step of causing the surface to be adsorbed, and a nucleation step of drawing a desired pattern on the surface of the substrate on which the source gas is adsorbed with light having a predetermined wavelength that is equal to or smaller than the diffraction limit to generate a nucleus;
A film growth step of supplying the raw material gas again to the substrate surface and selectively growing a film by a photochemical reaction in a portion where the nucleus is generated.

Another patterning method of the present invention proposed to solve the above-mentioned problem is a patterning method for forming a pattern of an arbitrary shape on a material surface, wherein a reactive gas for etching the material surface is provided on the substrate surface. A nucleation step of drawing a desired pattern on the surface of the material on which the reaction gas has been adsorbed with light of a predetermined wavelength that is equal to or smaller than the diffraction limit to generate a nucleus; and An etching step of supplying the reaction gas to the surface again and selectively removing a portion of the material surface on which nuclei are generated by a photochemical reaction.

Further, the present invention provides a patterning apparatus for forming a pattern of an arbitrary shape on a surface of a material, comprising: a reaction container for accommodating a material having a pattern formed on the surface; Gas supply means for supplying a gas for removal into the reaction vessel, exhaust means for discharging the gas in the reaction vessel, and a gas supply means provided in the reaction vessel and having a desired surface on a material surface on which the reaction gas is adsorbed And a drawing means for drawing a pattern with light having a size equal to or less than the diffraction limit and having a predetermined wavelength to selectively generate a nucleus.

According to the present invention, there can be provided a patterning method and a patterning apparatus which can form a pattern of an arbitrary shape including a dimension shorter than the diffraction limit of light and which does not require a mask.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a patterning method and a patterning apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows a basic configuration of a patterning apparatus according to the present invention.

This patterning apparatus comprises a source gas supply system, a reaction vessel, and an exhaust system.

The source gas supply system includes a source gas supply source S1,
It comprises a carrier gas supply source S2, valves V1, V2, V3, a mass flow controller 10, and piping connecting these to the reaction vessel.

A cylinder or the like is used as the source gas supply source S1 and the carrier gas supply source S2. The carrier gas is used for transporting the above-mentioned raw material gas after diluting it to an appropriate concentration for the reaction, and usually an inert gas is used.

The valve V1 is for adjusting the amount of the source gas supplied from the source gas supply source S1, and the valve V2 is for controlling the amount of the source gas supply source S2 from the carrier gas supply source S2.
This is for adjusting the amount of the carrier gas supplied to 1. Further, the valve V3 is connected to a carrier gas supply source S2.
Therefore, the amount of the carrier gas added to the source gas mixed with the carrier gas is adjusted.
The mixing ratio of the source gas and the carrier gas is determined by the valves V1, V2, and V3 so as to have a predetermined concentration.

The mass flow controller 10 is for precisely controlling the supply amount (mass flow rate) of the raw material gas mixed with the carrier gas at a predetermined ratio by the valves V1, V2 and V3.

The reaction vessel includes a vacuum chamber 20 and drawing means (not shown) for forming a desired pattern on a substrate housed therein.

The vacuum chamber 20 is a container for accommodating a substrate therein and maintaining a high-vacuum or gas atmosphere at an arbitrary pressure, and includes a window for observing the inside and various kinds of It has a port to which equipment can be attached. Source gas is introduced into the vacuum chamber 20 via the mass flow controller 10. Drawing means (not shown) inside the vacuum chamber 20 will be described later.

The whole reaction vessel is desirably installed on a surface plate or a vibration isolation table in order to block external vibrations.

The evacuation system is for making the inside of the vacuum chamber 20 have an arbitrary pressure, and is constituted by a vacuum pump connected via a valve V4. Here, a turbo-molecular pump 31 that can operate from a relatively high pressure to evacuate to a high vacuum and obtain a relatively high evacuation speed even for a light gas, and an oil rotary pump (rotary) as its auxiliary pump (Pump).

It is to be noted that the vacuum system 20 is
Is discharged after being subjected to post-processing as required.

Next, the drawing means inside the vacuum chamber 20 will be described.

As described above, in the conventional selective patterning method using light, since light propagating in free space is condensed and used, a processing accuracy (spatial resolution) of about 0.1 μm or less is realized. It was impossible to do.

On the other hand, since the drawing means applied to the patterning apparatus according to the present invention described below does not use light propagating in free space, the above-described processing accuracy can be realized. .

FIG. 2 shows a tip of an optical fiber for making light for drawing a desired pattern on a material surface smaller than a diffraction limit.

The optical fiber 122 has an opaque metal film 123 after one end is sharpened by a method such as etching.
Are attached. Sharpened tip 121
The metal film 123 is removed, the core is exposed, and an opening having a diameter smaller than the wavelength in the visible region (about 0.5 μm) is formed. Hereinafter, the optical fiber thus processed is referred to as a probe.

When light is incident from the rear end of the probe 120, light as a normal wave is not emitted from the distal end portion 121, but a light field called an evanescent field exudes. By irradiating the probe 120 with the light of the evanescent field 130 and irradiating the material surface 110 with a fine movement using a piezoelectric actuator or the like and scanning, a desired pattern including a dimension shorter than the diffraction limit of the light is drawn on the material surface 110. can do.

The distance between the probe 120 and the material surface 110 is controlled by detecting a shear force.

The evanescent field 130 is a non-propagating component of the light existing in a very close area (near field area) which is less than the light wavelength from the tip of the probe 120.

The power of light in the evanescent field 130 is
Although it decreases as the distance from the tip of the probe 120 decreases, the “thickness of the seepage” representing the degree of the decrease is substantially the same as the dimension of the tip 121 of the probe 120 and does not depend on the light wavelength. The light in the evanescent field 130 has a power density per unit sectional area of 100 W /
Since it reaches cm ² , a photochemical reaction can be induced by bringing the tip of the probe 120 closer to the material surface 110.

Next, the patterning method of the present invention will be described with reference to the configuration of the patterning apparatus of FIG. 1 and the configuration of the probe of FIG.

In this patterning method, a photochemical reaction is induced by the light of the evanescent field 130 seeping out from the tip 121 of the probe 120 to selectively deposit a substance on a substrate or remove the surface of the substance. ,
This is to form a pattern of an arbitrary shape with a processing accuracy equal to or less than the wavelength of light.

FIG. 3 shows a basic procedure for forming a thin film of an arbitrary shape on a substrate by the patterning method of the present invention.

Step S1 is a source gas adsorption step in which a source gas (base gas) 113 for forming a thin film is formed.
Is introduced into the vacuum chamber 120 and is adsorbed on the surface of the substrate 111.

In step S2, the source gas 130 introduced into the vacuum chamber 120 is once exhausted by the evacuation system. At this time, the source gas adsorption layer 112 remains on the surface of the substrate 111.

Step S3 is a nucleation step in which the probe 12 is formed only on the portion of the substrate 111 where a film is to be deposited.
A desired pattern is drawn by irradiating light from the front end of the zero. The light irradiated here is the light of the evanescent field 130 described above. The wavelength of this light is selected so that the light (photon) energy is equal to or greater than the dissociation energy for photolyzing molecules of the source gas 130. As a result, nuclei for film growth are selectively generated only in the portion of the substrate 111 where a thin film is to be formed.

In step S4, the source gas 130 is introduced again into the vacuum chamber 120, and is brought to a predetermined pressure.

Step S5 is a film growth step, in which the thin film source gas (base gas) 113 is supplied while irradiating the laser beam (excitation light) 115 that has not been focused onto the source gas adsorption layer 112 on the surface of the substrate 111. By doing so, the nucleus 114 selectively generated according to the drawn pattern shape
A thin film is grown from the thin film to form a desired pattern.

FIG. 4 schematically shows each of the above steps. FIG. 4 (a) is a raw material gas adsorption step, and FIG.
Represents a nucleation step, and FIG. 4C represents a film growth step.

Various materials such as silicon, glass, and sapphire can be used for the substrate 111. The substrate 111 is preliminarily subjected to pretreatment such as degreasing and cleaning. This degreasing cleaning is performed by ultrasonic cleaning using pure water and isopropyl alcohol, for example.

In each of the above steps, the substrate temperature is set to room temperature.

According to these steps, selective growth without using a mask (maskless) can be performed by using a photochemical vapor deposition method (photo CVD method).

A thin film to be patterned is formed on the substrate 111 in advance, and the source gas 13 to be introduced is formed.
If 0 is appropriately selected, selective etching can be performed in the same process to pattern into an arbitrary shape.

Next, the optical CVD used in the above-described patterning method of the present invention will be further described.

FIG. 5 shows the principle of the photo-CVD method.
When light 115 is applied to the molecules of the raw material gas 113, the light (photons) 115 becomes larger than the dissociation energy Eg of the raw material gas 113.
Is large, the molecules of the source gas 113 are dissociated into atoms 113a and 113b. This process is photolysis. Here, h is Planck's constant, and ν is the frequency of light.

By depositing only the atoms 113a generated by the photolysis on the substrate 111, a target thin film 114 can be obtained. On the other hand, the target thin film 1
The atoms 114b that are not required to obtain 14 are quickly discharged from the vacuum chamber 20, which is a reaction vessel. As described above, the vacuum chamber 20
By appropriately selecting the type of the source gas introduced into the inside, the thin film 114 can be selectively removed by a product generated by photolysis.

Such an optical CVD method has excellent features such as good process controllability and high throughput, a variety of applicable materials, and little damage to the resulting film. I have. Note that materials to which the photo CVD method can be applied will be specifically described later.

FIG. 6 schematically shows the dissociation energy required for dissociating the molecules of the raw material gas 113.

The potential curve 61 shows the relationship between the internuclear distance of the atoms constituting the molecule and the potential energy E. That is, the energy required to decompose the molecules of the source gas 113 and sufficiently separate the atoms 113a and 113b corresponds to the dissociation energy Eg. Further, the dissociation potential curve 62 is a curve that decreases in inverse proportion to the internuclear distance of the atoms constituting the molecule.

The process for dissociating the molecules of the source gas 113 includes the above-described process by photolysis and the process by thermal decomposition. Photolysis proceeds along a potential curve 62, and thermal decomposition proceeds along a potential curve 61. Therefore, the dissociation potential curve 62 and the potential curve 61
When the energy corresponding to the difference is supplied as the energy hv of the excitation light, photolysis is the dominant process.

FIG. 7 shows the relationship between the dissociation energy of the organometallic gas Al (CH ₃ ) ₃ and the wavelength of the excitation light as an example of the source gas used in the photo-CVD method. In this figure, the abscissa indicates the wavelength of light irradiated on Al (CH ₃ ) ₃ , and the ordinate indicates the transmittance of the irradiated light. The vertical axis is an arbitrary scale.

Since the light wavelength corresponding to the dissociation energy of Al (CH ₃ ) ₃ is 429 nm, when the second harmonic (wavelength λ = 257 nm) of, for example, an Ar ⁺ laser is used as the excitation light source, Al It can be seen that the molecules of the (CH ₃ ) ₃ gas are dissociated.

FIG. 8 shows an example of the relationship between the deposition rate and the power of the laser beam applied to a film formed using the patterning method and patterning apparatus of the present invention described above. Here, Zn (C
Using H _{3) 2,} pressure 6.65 × 10 ² Pa (5Tor
r. ) And 1.33 × 10 ³ Pa (10 Torr.)
The results in the case where the film is formed in the above manner are shown.

As described above, as the irradiation laser power and the pressure of the source gas increase, the deposition rate of the film increases.

FIGS. 9 to 11 show specific examples of materials which can obtain good results by applying the present invention described above, and material gases and excitation light sources suitable for the materials. 9 shows a case where a metal is obtained as a product, FIG. 10 shows a case where a semiconductor material is obtained, and FIG. 11 shows a case where a dielectric is obtained. In the pumping light source shown in FIG. 9, SH is the second harmonic (Secondary Harm).
onics).

As described above, the present invention is applicable to a wide variety of materials and can be applied to various uses. For example, a phase shifter used in a manufacturing process of a gigabit class DRAM (Dynamic Random Access Memory) or the like can be used. Tools to fix mold photomasks,
The present invention is also applicable to a new process for realizing a quantum effect device by selectively forming semiconductor fine particle crystals.

[0059]

According to the patterning method and the patterning apparatus of the present invention, a desired pattern is drawn on the surface of a material by the light of an evanescent field to generate nuclei, and a substance is selectively used by utilizing a photochemical reaction. Since the deposition or the removal is performed, a pattern having an arbitrary shape including a dimension shorter than the wavelength of light can be directly formed without using a mask.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a basic configuration of a patterning apparatus of the present invention.

FIG. 2 is a diagram showing a tip portion of an optical fiber probe for making light for drawing a desired pattern on a material surface smaller than a diffraction limit.

FIG. 3 is a flowchart showing a basic procedure for forming a thin film on a substrate by the patterning method of the present invention.

FIG. 4 is a diagram for explaining main steps of the patterning method of the present invention.

FIG. 5 is a diagram for explaining a photo CVD method.

FIG. 6 is a diagram for explaining the dissociation energy of source gas molecules.

FIG. 7 is a diagram showing the relationship between the dissociation energy of Al (CH ₃ ) ₃ and the wavelength of excitation light as an example of a source gas.

FIG. 8 is a diagram showing an example of the relationship between the deposition rate of a film and the power of an irradiated laser beam.

FIG. 9 is a diagram showing specific examples of a metal material obtainable by applying the present invention, a raw material gas and an excitation light source suitable for the metal material.

FIG. 10 is a diagram showing specific examples of a semiconductor material which can be obtained by applying the present invention, a raw material gas and an excitation light source suitable for the semiconductor material.

FIG. 11 is a diagram showing specific examples of a dielectric material obtainable by applying the present invention, a raw material gas and an excitation light source suitable for the dielectric material.

[Explanation of symbols]

111 substrate, 112 source gas adsorption layer, 113
Source gas, 114 thin film, 114a nucleus, 115
Laser light, 120 probe, 121 tip

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ identification code FI H01L 21/316 H01L 21/316 X (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 16/00-16 / 56 C23F 1/00-4/04 G03F 1/08 G03F 7/20 H01L 21/205 H01L 21/28-21/285 H01L 21/302 H01L 21/31-21/32 JICST file (JOIS)

Claims (15)

(57) [Claims] In a patterning method for forming a pattern of an arbitrary shape on a surface of a material, a source gas adsorbing step of adsorbing a source gas for forming a film on a substrate surface; A nucleation step of drawing a pattern with light of a predetermined wavelength not larger than the diffraction limit to generate nuclei; and supplying the raw material gas again to the substrate surface, and photochemically forming a nucleus at the portion where the nuclei are generated. A film growth step of selectively growing a film by a reaction. 2. The patterning method according to claim 1, wherein the energy of the light having the predetermined wavelength is equal to or more than the energy required for photodecomposing the raw material gas. 3. The patterning method according to claim 1, wherein the desired pattern drawn by the light has a portion whose dimension is shorter than the wavelength of the light used for the drawing. 4. The patterning method according to claim 1, wherein the light used for the drawing is light in an evanescent field. 5. The light of the evanescent field is emitted from an opening having a diameter smaller than the light wavelength of the evanescent field, which is provided at the tip of an optical fiber having a tapered and opaque metal film. 2. The patterning method according to claim 1, wherein the irradiation is performed. 6. A patterning method for forming a pattern of an arbitrary shape on a surface of a material, comprising: a step of adsorbing a reaction gas for etching a surface of the material onto a surface of a substrate; A nucleus generating step of drawing a pattern with light of a predetermined wavelength that is equal to or smaller than the diffraction limit to generate a nucleus, and supplying the reaction gas again to the substrate surface to generate a nucleus on the material surface. An etching step of selectively removing the portion by a photochemical reaction. 7. The patterning method according to claim 6, wherein the energy of the light having the predetermined wavelength is equal to or more than the energy required for photodecomposing the source gas. 8. The patterning method according to claim 6, wherein the desired pattern drawn by the light has a portion whose dimension is shorter than the wavelength of the light used for drawing. 9. The patterning method according to claim 6, wherein the light used for writing is light in an evanescent field. 10. The light of the evanescent field is emitted from an opening having a diameter smaller than the light wavelength of the evanescent field, provided at the tip of an optical fiber having a tapered and opaque metal film. 7. The patterning method according to claim 6, wherein the irradiation is performed. 11. A patterning apparatus for forming a pattern of an arbitrary shape on a surface of a material, comprising: a reaction vessel containing a material on which a pattern is to be formed on the surface; and a reaction vessel for depositing on the surface of the material or removing the surface of the material. Gas supply means for supplying a gas into the reaction vessel; exhaust means for exhausting the gas from the reaction vessel; and a diffraction limit of a desired pattern on a surface of the material provided in the reaction vessel and adsorbing the reaction gas. A patterning device comprising: drawing means for selectively generating nuclei by drawing with light of a predetermined wavelength having the following size. 12. The patterning apparatus according to claim 11, wherein the energy of the light having the predetermined wavelength is equal to or more than the energy required for photodecomposing the source gas. 13. A light irradiating means for irradiating the drawn material surface with light to induce a photochemical reaction in the selectively formed nucleus portion. Patterning equipment. 14. The patterning apparatus according to claim 11, wherein the light radiated by the drawing means and having a size smaller than the diffraction limit is light in an evanescent field. 15. The light of the evanescent field is transmitted from an opening having a diameter smaller than the light wavelength of the evanescent field, which is provided at the tip of an optical fiber having a tapered and opaque metal film. The patterning apparatus according to claim 11, wherein the patterning is performed.