JP4245290B2 - Fine pattern drawing material and fine processing method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to novel fine pattern writing materials, more particularly, between the inorganic substance capable of generating an alloy having a different etch rate with both heated reaction metal which generates heat by absorbing light and a metal The present invention relates to a fine pattern drawing material that can be drawn using the heating reaction and a method of fine processing using the drawing material.
[0002]
[Prior art]
In recent years, in the optical recording technology, higher density recording has been demanded, and in the near future, a recording density of 100 gigabits per inch square is expected. Along with this, research has also been conducted on optical recording media and technologies, such as the formation of fine patterns with dimensions of 100 nm or less, the use of blue lasers and near-field light for reproducing them.
[0003]
Incidentally, one of optical recording technologies is ROM (Read Only Memory), that is, a read-only optical recording medium in which pits are created in an optical disc. Naturally, it is necessary to make it. The ROM is mass-produced by copying with a stamper. The stamper includes a structure corresponding to a pit, and this structure is usually formed by a lithography method using a photoresist. Until now, the miniaturization of this structure has been dealt with by shortening the wavelength of the laser and increasing the aperture. However, the shortening of the wavelength requires the development of a laser light source, and for short wavelengths. Since optical materials are required, the cost is inevitable. In addition, there is a bottleneck that an optical system to be used for the high aperture must be developed. In addition, a method of creating a bit by using an electron beam drawing method is also known, but this requires a vacuum facility and a high-voltage power supply, which increases costs.
[0004]
In order to overcome the disadvantages of this method, the heat generated by the laser beam is used to change the crystal state of the chalcogen compound, and fine processing is performed using the difference in the etching rate based on the difference in the crystal state. Have been proposed ( Japanese Patent Laid-Open No. 10-97738 ) and a method of drawing by irradiating a laser spot on a laminated material having a resist layer that can be directly drawn by a laser ( Japanese Patent Laid-Open No. 2000-235256 ). .
[0005]
However, in the method using the difference in crystal state of the chalcogen compound, the difference in etching rate based on the difference in crystal state is not so large, and it is difficult to form a uniform film of the chalcogen compound. However, the etching rate is partially different, especially because the grain boundary part is etched quickly, and there is a disadvantage that the desired fine processing is not performed. There was a problem.
[0006]
In the drawing method by direct exposure of laser light, the limit of the dimension that can be processed is limited by the diffraction limit. Therefore, laser light having a wavelength corresponding to the fine processing dimension is indispensable. Therefore, in order to reduce the processing size, it is necessary to develop the laser light source itself, and the development of a resist corresponding to the light becomes indispensable, and it is inevitable that the cost becomes high.
[0007]
[Problems to be solved by the invention]
Under such circumstances, the present invention does not require the use of an expensive and large-scale apparatus, and uses an existing low-cost laser light source and realizes a processing dimension far exceeding the diffraction limit. The present invention has been made for the purpose of providing a material and a fine processing method using the material.
[0008]
[Means for Solving the Problems]
As a result of intensive research to develop a novel fine pattern drawing material, the present inventors utilize the fact that a temperature distribution is generated in the spot of the narrowed beam light, and absorb light in a wide range of wavelengths. a layer comprising a specific metal which generates heat and, a portion reacts with the metal and a layer comprising a specific inorganic substance capable of alloying laminated, heating it in irradiated with light, alloyed and alloyed And found that if a fine pattern is formed by etching using the difference in etching rate with the unchanged part, fine processing can be easily performed without using expensive and large-scale equipment and special materials. The present invention has been made based on the above.
[0009]
That is, the present invention has a structure in which a composite layer of a metal layer (A) made of gold and an inorganic material layer (B) made of silicon is laminated on a substrate, and the metal layer (A And the inorganic material layer (B) react to form an alloy layer (C) having an etching rate different from that of the metal layer (A) and the inorganic material layer (B). A material, and an inorganic substance that forms a metal layer (A) and an inorganic substance that forms a metal layer (A) by irradiating the fine pattern drawing material with a focused light beam to generate heat in the metal layer (A). After forming an alloy layer (C) having an etching rate different from that of the metal layer (A) and the inorganic material layer (B), the alloy layer (C) is treated with an etching gas, and the etching process is performed using the difference in the etching rate. Provide a fine processing method characterized by It is intended.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an enlarged cross-sectional view for explaining the principle of the present invention. In this figure, on a transparent substrate 1, a metal that generates heat by light irradiation, that is, a gold layer 3 and a metal layer (A ) To form an alloy, that is, a composite layer composed of the silicon layer 4 is laminated via the protective layer 2, and the alloy includes a metal layer (A) and an inorganic material layer (B). Constitutes a fine pattern drawing material having different etching rates.
In addition, as long as said conditions are satisfy | filled, even if an inorganic substance layer (B) generate | occur | produces heat by light irradiation, it does not interfere.
[0011]
When irradiated with a laser beam 6 on the fine pattern writing material from the side of the substrate 1 through the lens 7, the light collected is drawn in the layer (A) i.e. third metal is converted into heat, as a result of generating heat, the metal layer (A) and the inorganic material layer (B) react with heat to produce an alloy layer (C), that is, 5. Since the protective layer 2 is provided to protect the substrate 1 from the heat generated by laser light irradiation, the protective layer 2 can be omitted if the substrate 1 has heat resistance. . Further, in this structural example, since a transparent material is used as the substrate 1, the laser beam is irradiated from the substrate side. However, when an opaque substrate material is used, the metal layer (A), that is, 3 and the inorganic material layer (B), that is, the arrangement of 4 is reversed, and the laser beam is irradiated from the side opposite to the substrate 1. At this time, if a light-absorbing substance is used as the constituent of the inorganic substance layer (B) , there is no need to make the reverse.
[0012]
Next, FIG. 2 is a graph showing the light intensity distribution in the spot of the light collected on the metal layer (A), that is, 3, which constitutes a typical Gaussian distribution and shows the center of the spot. The intensity of light is high, and the intensity of light decreases with increasing distance from the center. Then, by utilizing the fact that the intensity distribution of this beam light spot forms a Gaussian distribution, it is possible to make the heat generation region above a certain temperature much smaller than the light spot and realize a fine processing dimension below the diffraction limit. it can.
[0013]
Since alloying proceeds at a temperature higher than a predetermined temperature, the intensity of light can be adjusted and can be caused only in a narrow area at the center of the spot, so that heat is applied in a fine area far beyond the diffraction limit. After a reaction is performed and a fine pattern is drawn, fine processing can be performed by etching.
[0014]
In this case, the relationship between the etching rates of the reaction region and the unreacted region may be large for the former and small for the latter, or conversely, the former may be small and the latter may be large. In any case, due to this difference in etching rate, either the laser light irradiation region or the non-irradiation region can be removed by etching, and the other can be left.
[0015]
The substrate 1 in the fine pattern drawing material of the present invention can be arbitrarily selected from those usually used as a substrate when manufacturing electronic and electrical parts by lithography. Examples of such materials include inorganic substrates such as silicon, tantalum, aluminum, gallium-arsenic, and glass plates, and plastic substrates such as polypropylene, acrylic resin, polycarbonate, styrene resin, and vinyl chloride resin. Other alumina, tantalum oxide, may also be used as coated with those depositing aluminum or tantalum and the photocurable resin layer on an inorganic substrate or a glass plate on such as silicon oxide.
[0016]
Next, gold is used as the metal of the metal layer (A) that generates heat by light irradiation. As the material of the inorganic substance layer (B) used in combination with the metal, a material that can be alloyed by reacting with gold forming the metal layer (A) by heat, that is, silicon is used.
[0017]
Since easily alloyed gold and silicon, used in combination with silicon gold as the metal, and as the inorganic material.
The metal layer (A) and the inorganic material layer (B) have a layer thickness ratio that provides a stable composition ratio when alloyed, or a layer thickness that provides a composition ratio that forms an alloy with low activation energy. It is preferable to use a ratio or a layer thickness ratio that provides a stoichiometric composition.
[0018]
Next, as the protective layer 2, for example, an inorganic compound such as ZnS · SiO ₂ or an organic compound such as polyimide is used. The thickness of the protective layer is usually selected within the range of 50 to 500 nm, but this thickness depends on the wavelength of light used and the material of the protective layer, and in some cases, the thickness may be outside this range. There is also.
[0019]
In microfabrication using the fine pattern drawing material of the present invention, beam light is irradiated to generate an alloy part in a desired region, and the difference in etching rate between the alloy part and the non-alloy part is utilized. Then, by removing one and leaving the other, a fine structure is formed.
[0020]
FIG. 3 is a cross-sectional explanatory view for explaining microfabrication according to the present invention. That is, the fine pattern drawing material having the alloyed portion formed by the method of FIG. 2 is exposed to the etching gas 8 and etched.
At this time, by using the etching rate of the inorganic electrolyte layer 4 is large etching gas, following the left path, to remain alloying moiety, the use of the etching speed is high etching gas alloying portion Conversely, the right Following the path, the alloying part is removed. In this way, by selecting the type of etching gas, etching of the alloy portion and non-alloy portion can be arbitrarily selected and performed .
In Figure 3, there is shown an example in which etching only inorganic electrolyte layer 4, to the metal layer 3 may be etched, it is possible to all the material layer or alloy layer 5 after the reaction etching.
[0021]
As a light source in the fine pattern drawing method of the present invention, it can be appropriately selected from various active lights used in general fine pattern drawing as needed. Examples of such active light include visible light, deep ultraviolet light, electron beam, i-line, g-line, KrF excimer laser, and ArF excimer laser.
[0022]
Moreover, as shown in FIG. 4, the fine pattern drawing material of the present invention can be drawn while heating the whole with a heater 9. In this way, since the output of the laser beam can be reduced, it is possible to prevent a rapid temperature rise or a rapid expansion or other deformation of the material due to the heat generated by the laser beam.
This heating can be performed by irradiating another laser beam instead of using a heater.
[0023]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
[0024]
Example After depositing ZnS.SiO ₂ with a thickness of 200 nm on a polycarbonate disk substrate (diameter 120 mm, thickness 0.6 mm) to form a protective layer, gold 14 nm and silicon 6 nm thereon by sputtering. Were laminated to produce a fine pattern drawing material.
Next, this fine pattern drawing material is mounted on an optical disk drive tester and irradiated with a pulse laser beam of 6 MHz and a duty of 50% while rotating at a linear speed of 6 m / s to form a gold-silicon alloy region having a size of 500 nm. Formed.
Subsequently, when the uppermost silicon layer was etched using carbon tetrafluoride as an etching gas, the silicon portion was removed, and the alloy portion remained to form a fine pattern. Since the numerical aperture in this experimental system is 0.6 and the laser beam wavelength is 630 nm, the diffraction limit is 530 nm. Therefore, it can be seen that a smaller structure is formed.
The result of observing the surface of the sample thus obtained with an atomic force microscope is shown in FIG.
[0025]
【The invention's effect】
The fine pattern drawing material and fine pattern drawing method of the present invention do not require use of a large-scale apparatus, and can perform fine processing far smaller than the diffraction limit.
In addition, according to the present invention, since it is possible to process to a size far smaller than the diffraction limit of the light to be used and the material made of an inorganic substance is used, the wavelength range of light to be absorbed ranges from the infrared region to the ultraviolet region. There is an advantage that a wide range can be selected.
That is, when light in such a wide area is used, an optical device such as an existing lens or mirror can be used, which is low in cost .
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view showing a structural example of a fine pattern drawing material of the present invention.
FIG. 2 is a graph showing a light intensity distribution in a light spot in a metal layer that generates heat by irradiation light.
FIG. 3 is an enlarged sectional view showing an etching process in the method of the present invention.
FIG. 4 is an explanatory diagram of a drawing method of the present invention performed while heating.
FIG. 5 is an atomic force microscope photograph of the fine pattern obtained in the example.
[Explanation of symbols]
Gold layer which generates heat by 1 substrate 2 protective layer 3 light irradiation (A)
4 gold layer as the layer of silicon to the alloy by heating the reaction with (A) (B)
5 Alloy layer (C)
6 Irradiation light 7 Lens 8 Etching gas 9 Heater

Claims (5)

A composite layer of a metal layer (A) made of gold and an inorganic material layer (B) made of silicon is laminated on a substrate, and the metal layer (A) and the inorganic material layer are irradiated by light irradiation. A fine pattern drawing material, wherein (B) reacts to form an alloy layer (C) having an etching rate different from that of the metal layer (A) and the inorganic material layer (B).   The fine pattern drawing material according to claim 1, further comprising a protective layer between the substrate and the composite layer. The fine pattern drawing material according to claim 1 or 2 is irradiated with a focused beam of light to cause the metal layer (A) to generate heat, thereby forming a metal and an inorganic substance layer (B) forming the metal layer (A). is reacted with an inorganic substance, after having formed an alloy layer (C) having different etch rates metal layer (a) and the inorganic material layer (B), and treated with an etching gas, using the difference in etching rate A fine processing method characterized by etching. 4. The microfabrication method according to claim 3, wherein the etching gas is carbon tetrafluoride. Claim 3 or 4 microfabrication method according to heating area is smaller than the irradiation area of the light beam of the metal layer by changing the irradiation conditions of the light beam (A).

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