JP2004286570A - Nanopillar sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop an application technique for a pillar having a high aspect ratio, obtained by a nanoprinting method. <P>SOLUTION: The nanopillar sensor consists of the nanopillar formed on a substrate, by a pattern transfer method for heating/pressing the substrate and a stamper on whose surface a fine recession and a protrusion are formed, more specifically, the capacitance sensor is composed of two facing electrodes and a columnar structure (pillar) and for sensing the electrostatic capacity by the inclination of the nanopillar. By employing the nanoprinting method, the capacitance sensor having high sensitivity is manufactured at a low cost, as compared with the conventional capacitance sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an application of nanopillars formed on a substrate by a pattern transfer method of heating and pressing a substrate and a stamper having fine irregularities formed on the surface using a nanoprinting apparatus.
[0002]
[Prior art]
2. Description of the Related Art In recent years, miniaturization and integration of semiconductor integrated circuits have been advanced, and photolithography apparatuses have been improved in precision as a pattern transfer technique for realizing the microfabrication. However, the processing method is approaching the wavelength of the light source for light exposure, and the lithography technique is approaching its limit. For this reason, an electron beam lithography apparatus, which is a kind of charged particle beam apparatus, has come to be used in place of the lithography technique in order to achieve further miniaturization and higher precision.
[0003]
The pattern formation using an electron beam is different from the collective exposure method in pattern formation using a light source such as an i-line or an excimer laser, and is based on a method of drawing a mask pattern. It is a drawback that exposure (drawing) takes time and pattern formation takes time. Therefore, as the degree of integration is dramatically increased to 256 mega, 1 giga, and 4 giga, the pattern formation time is drastically increased correspondingly, and there is a concern that the throughput may be significantly inferior. Therefore, in order to increase the speed of the electron beam lithography system, the development of a collective pattern irradiation method that combines masks of various shapes and irradiates them collectively with an electron beam to form an electron beam of a complicated shape is being advanced. . As a result, while the pattern miniaturization is advanced, the electron beam lithography system must be increased in size, and a mechanism for controlling the mask position with higher accuracy is required. was there.
[0004]
On the other hand, techniques for forming a fine pattern at low cost are disclosed in Patent Literatures 1 and 2, Non-Patent Literature 1, and the like. This is to transfer a predetermined pattern by stamping a stamper having the same pattern irregularities as a pattern to be formed on a substrate onto a resist film layer formed on the surface of a substrate to be transferred. According to the nanoimprint technique described in Document 2 and Non-Patent Document 1, it is stated that a microstructure of 25 nm or less can be formed by transfer using a silicon wafer as a stamper.
[0005]
[Patent Document 1]
US Patent No. 5,259,926 [Patent Document 2]
US Patent No. 5,772,905 [Non-Patent Document 1]
S. Y. Chou et al. , Appl. Phys. Lett. , Vol. 67, p. 3314 (1995)
[0006]
[Problems to be solved by the invention]
Therefore, the present inventors use a nanoprinting press device to heat and press a stamper on which fine irregularities are formed on the substrate and the surface. We succeeded in producing columnar structures (nano pillars).
An object of the present invention is to develop an application technology of a nanopillar formed on a substrate.
[0007]
[Means for Solving the Problems]
The present inventor has thought of applying nanopillars to various sensors, and has reached the present invention.
That is, the present invention is a nanopillar sensor including nanopillars formed on a substrate by a pattern transfer method of heating and pressing a substrate and a stamper having fine irregularities on the surface using a nanoprinting apparatus.
[0008]
Specifically, it is an electrostatic capacitance sensor that is composed of two opposing electrodes and a columnar structure (pillar) and senses the electric capacitance by the inclination of the nanopillar. By using the nanoprinting method, the number of steps can be reduced as compared with a conventional capacitance sensor, and a high-sensitivity capacitance sensor can be manufactured at low cost. By sensing the electric capacitance by the inclination of the nanopillar, it can be used for a flow sensor or an acceleration sensor.
[0009]
In addition, as a method of manufacturing a nanopillar by molding a resin substrate or a resin film on the substrate, (1) heating and deforming the resin film on the resin substrate or the substrate; It is preferable to select from the following: (3) photo-curing the resin film after pressure molding and (3) photo-curing the resin substrate or the resin film on the substrate.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
First, the nanoprinting method will be described with reference to FIG. A stamper having a fine pattern on the surface of a silicon substrate or the like is manufactured. A resin film is provided on another substrate (FIG. (A)). A pressing device having a heating / pressing mechanism (not shown) is used at a temperature equal to or higher than the glass transition temperature (Tg) of the resin and a predetermined pressure is applied. Press the stamper on the resin film (FIG. (B)). It is cooled and hardened (Fig. (C)). The stamper and the substrate are separated, and the fine pattern of the stamper is transferred to the resin film on the substrate (FIG. (D)). Alternatively, instead of the step of heating and curing, a photocurable resin may be used, and after molding, the resin may be irradiated with light to cure the resin. Further, a light-transmitting stamper such as glass may be used, and after pressing, light may be irradiated from above the light-transmitting stamper to light-cur the resin.
[0011]
According to the nanoprinting method, (1) the integrated ultra-fine pattern can be efficiently transferred, (2) the apparatus cost is easy, (3) it is possible to cope with complicated shapes and pillars can be formed, and the like. There are features.
[0012]
In the present invention, nanoprinting refers to transfer in the range from several hundreds of μm to several nm.
In the present invention, a press device having a heating / pressing mechanism or a device having a mechanism capable of irradiating light from above the light-transmitting stamper is preferable for efficient pattern transfer.
[0013]
In the present invention, the stamper has a fine pattern to be transferred, and a method of forming the pattern on the stamper is not particularly limited. For example, it is selected according to a desired processing accuracy such as photolithography or electron beam lithography. As the material of the stamper, any material having strength and required workability such as silicon wafer, various metal materials, glass, ceramic, plastic, etc. may be used. Specifically, Si, SiC, SiN, polycrystalline Si, glass, Ni, Cr, Cu, and those containing at least one of them are preferably exemplified.
[0014]
In the present invention, the material used as the substrate is not particularly limited, but may be any material having a predetermined strength. Specifically, silicon, various metal materials, glass, ceramic, plastic, and the like are preferably exemplified.
[0015]
In the present invention, the resin film to which the fine structure is transferred is not particularly limited, but is selected according to a desired processing accuracy. Specifically, polyethylene, polypropylene, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, polyvinyl chloride, polystyrene, ABS resin, AS resin, acrylic resin, polyamide, polyacetal, polybutylene terephthalate, glass reinforced polyethylene terephthalate, polycarbonate, modified Thermoplastic resins such as polyphenylene ether, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, fluororesin, polyalate, polysulfone, polyethersulfone, polyamideimide, polyetherimide, thermoplastic polyimide, phenolic resin, melamine resin, urea Resin, epoxy resin, unsaturated polyester resin, alkyd resin, silicone resin, diallyl phthalate resin, poly Bromide bismaleimide, poly bisamide thermosetting resin triazole and the like, and it is possible to use two or more kinds of these blended material.
Among them, in order to obtain conductive nanopillars, a conductive resin can be used, or a resin containing a conductive filler can be used.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, examples of the present invention will be described.
[Example 1: acceleration sensor]
FIG. 2 shows a nanopillar acceleration sensor 1 of the present invention. Polystyrene nanopillars 4 are formed between the upper electrode 2 and the lower electrode 3.
[0017]
Here, a nanopillar manufacturing process will be described. First, as shown in FIG. 3A, a 500 nm thick platinum thin film 6 was formed on a quartz substrate 5 having a smooth surface by a sputtering method. An OFPR800 resist manufactured by Tokyo Ohka Kogyo Co., Ltd. was applied thereon by spin coating to a thickness of 10 μm, and after exposure and development, a resist 7 was formed as shown in FIG. 3B. After removing the platinum thin film 6 by ion milling using the resist 7 as a mask, the resist was peeled off to form the lower electrode 3 of 10 mm × 10 mm as shown in FIG. 3C. Next, as shown in FIG. 3D, a polystyrene thin film 8 (manufactured by Polystyrene 679A & M) was applied on the lower electrode 3 by a screen printing method to a thickness of 500 nm. As shown in FIG. 3E, a polystyrene nanopillar 4 having a diameter of 500 nm and a height of 5 μm was formed on the polystyrene thin film 8 by the above-described nanoprinting, thereby forming a lower substrate 9. FIG. 4 is a scanning electron micrograph of the formed polystyrene nanopillar 4.
[0018]
FIG. 5 shows a manufacturing process of the nanopillar acceleration sensor. Similarly, a thermal oxide film was formed on the surface of the (001) silicon substrate 10 having a smooth surface, and a resist 11 was obtained as shown in FIG. 5B by the same method as the resist 7 of FIG. 3B. Using the resist 11 as a mask, the thermal oxide film on the surface of the silicon substrate 10 was partially removed. Using the partially removed thermal oxide film as a mask, a sensor section for forming an electrode and a flow path 12 having a width of 500 micrometers and a depth of 9.5 micrometers by anisotropic etching using a potassium hydroxide solution is shown in FIG. It was formed as shown in (c). Thereafter, a platinum upper electrode 2 having a size of 10 mm × 10 mm and a thickness of 500 nm was formed on the sensor portion by the same process as that for forming the lower electrode 3, thereby forming an upper substrate 13 as shown in FIG. The upper substrate 13 and the lower substrate 9 were joined with an adhesive 14 having a thickness of 2 micrometers as shown in FIG.
[0019]
The test results of the nanopillar acceleration sensor 1 of the present invention will be described with reference to FIGS. FIG. 7 is a configuration diagram of an experiment in which an acceleration 15 is applied to the nanopillar acceleration sensor 1 held in the air, and FIG. 8 shows the experiment result. Since the polystyrene nanopillars 4 were tilted by the acceleration 15, the capacitance between the two electrodes changed, and a decrease of up to 20% was shown. A strong correlation was found between the acceleration 15 and the change in capacitance, indicating that the nanopillar acceleration sensor 1 has a function as an acceleration sensor.
[0020]
[Example 2: Nano pillar flow sensor]
Hereinafter, another embodiment of the present invention will be described. FIG. 9 shows a nanopillar flow sensor 17 of the present invention. A polystyrene nanopillar 20 is formed between the upper electrode 18 and the lower electrode 19, and air 21 flows between the two electrodes.
[0021]
The formation process of this sensor is the same as that of the nanopillar acceleration sensor 1 shown in the first embodiment of the present invention, except that a connector 22 for introducing and discharging air 21 for measuring a flow rate to the sensor is formed outside the sensor. I have.
[0022]
The test results of the nanopillar flow sensor 17 of the present invention will be described with reference to FIGS. FIG. 9 is a configuration diagram of an experiment in which air 21 flows through the nanopillar flow sensor 17, and FIG. 10 shows the experiment result. Since the flow of the air 21 caused the polystyrene nanopillars 20 to tilt, the capacitance between the two electrodes changed, indicating a maximum reduction of 20%. A strong correlation was found between the flow rate of the air 21 and the change in capacitance, indicating that the nanopillar flow rate sensor 17 has a function as a flow rate sensor.
[0023]
【The invention's effect】
According to the present invention, by using the nanoprinting method, it is possible to manufacture a high-sensitive capacitance sensor at low cost as compared with a conventional capacitance sensor.
[Brief description of the drawings]
FIG. 1 is a schematic view showing each step of nanoprinting.
FIG. 2 shows a nanopillar acceleration sensor of the present invention.
FIG. 3 shows a nanopillar manufacturing process.
FIG. 4 is a scanning electron micrograph of the formed polystyrene nanopillars.
FIG. 5 is a manufacturing process of the nanopillar acceleration sensor.
FIG. 6 is a continuation of the manufacturing process of the nanopillar acceleration sensor.
FIG. 7 is a configuration diagram of an experiment in which an acceleration is applied to a nanopillar acceleration sensor held in the air.
FIG. 8 is a result of an experiment in which acceleration is applied to a nanopillar acceleration sensor held in air.
FIG. 9 is a configuration diagram of an experiment in which air flows through a nanopillar flow sensor.
FIG. 10 shows the results of an experiment in which air is flowed through a nanopillar flow sensor.

Claims (4)

A nanopillar sensor composed of nanopillars formed on a substrate by a pattern transfer method of heating and pressing a substrate and a stamper having fine irregularities on the surface using a nanoprinting press device. The nanopillar sensor according to claim 1, wherein the nanopillar sensor according to claim 1 is a capacitance sensor including two opposing electrodes and a columnar structure (pillar), and detecting a capacitance by a tilt of the nanopillar. The nanopillar sensor according to claim 2, wherein the nanopillar sensor is a flow sensor that senses capacitance by tilting the nanopillar. The nanopillar sensor according to claim 2, wherein the nanopillar sensor is an acceleration sensor that senses capacitance by a tilt of the nanopillar.

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