CN102092678A - Force modulation mode-based dip-pen nanolithography method - Google Patents

Abstract

The invention provides a force modulation mode-based dip-pen nanolithography method in the technical field of nanometer manufacture, which is realized by combining a tapping mode and the force modulation technology, imaging by the tapping mode and lithographing on a setpoint by the force modulation technology. The method can accurately control the acting force and the acting time between a tip and a substrate, so the lithographing effect can be better controller, and the repeatability of lithographing operation is improved; and furthermore, the method can perform multi-point automatic location and dip-pen lithography operation once, is convenient and practical, and is advantageous to industrialization.

Description

Dip pen nano-etching method based on force modulation mode

technical field

The invention relates to a method in the technical field of nano-manufacturing, in particular to a dip-pen nano-etching method based on a force modulation mode for nano-electronic devices and biochips.

Background technique

"Dip-pen nanolithography" is a nano-manufacturing technology that uses the tip of an atomic force microscope to transfer the substance adsorbed on the tip to the substrate through the action of the meniscus. People compare the needle point to a "pen", the substance on the needle point to "ink", and the etching process is analogous to writing on paper with a pen, so it is vividly called "dipping pen" nano-etching technology. Through this technology, people have been able to realize the transfer of biological macromolecules such as inorganic salts, small organic molecules and proteins on different substrates, and prepare functional graphics. (Science, 1999, 283: 661-663; Nature chemistry, 2009, 1: 353-358; PNAS, 2001, 98: 13660-13664)

At present, the main methods of realizing the "dipping pen" nano-etching technology at home and abroad are: contact mode, tapping mode, contact and tapping mixed mode and dynamic combination mode. Among them, the contact mode can be etched very conveniently by changing the value of SETPOINT because the distance between the needle tip and the substrate is small, but there is a shearing effect between the needle tip and the substrate during the etching process, which can only be achieved by 1/6 The imaging scanning speed is operated on a hard substrate surface; in the tap mode, the needle tip is in intermittent contact with the substrate surface, and the friction and shearing effects are small, and the etching can be performed by changing the value of DRIVE AMPLITUDE to manufacture nano-patterns of biological macromolecules ;Contact and tapping mixed mode uses contact mode for etching and tapping mode imaging, which combines the characteristics of easy etching in contact mode and imaging of soft samples in tapping mode, but contact mode and tapping are required after etching Subsequent mode conversion, needle point replacement and repositioning operations are cumbersome; the dynamic combination mode can realize instant conversion of tapping mode and contact mode, and realize the production of nano-patterns and imaging inspection at the same position. In the above methods, the meniscus is formed by reducing the distance between the needle tip and the substrate, thereby performing etching. However, changing the parameters of SETPOINT, DRIVE AMPLITUDE, and LIFT HEIGHT can only qualitatively change the distance between the needle tip and the substrate, and the force between the needle tip and the substrate cannot be precisely controlled, which requires empirical speculation; and is affected by parameters such as the elastic coefficient of the needle tip , even if the parameter changes are the same, the changes caused by them will be different, and the etching results are difficult to repeat; in addition, these methods must perform repeated operations point by point when etching, which takes a lot of time. (J Am ChemSoc, 2003, 125: 580-583; J Am ChemSoc, 2007, 129: 6668-6669; Chinese Science, 2004, 49: 444-447; Chinese Patent: Publication No. CN1654230A, CN1615457A)

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention provides a dipping pen nano-etching method based on the force modulation mode. By combining the tapping mode and the force modulation technology, the tapping mode is used for imaging, and the force modulation technology is used for imaging. Realized by fixed-point etching.

The present invention is achieved through the following technical solutions, and the present invention comprises the following steps:

The first step is to construct a nanosurface on the substrate surface by spin coating, evaporative drying, photolithography, soft etching, electron beam etching or ion beam etching on an atomically flat substrate surface to obtain a nanostructured surface. sample;

The second step is to immerse the probe in the inorganic salt solution, organic small molecule solution, colloid solution or biomacromolecule solution, take it out, and blow dry;

The third step is to control the ambient temperature of the atomic force microscope to be 4°C to 80°C, and the ambient humidity to be between 30%RH and 80%RH;

The fourth step is to use the modified probe to scan and record the surface information of the sample with nanostructure to select one or more etching positions, and then use the same probe to construct nano-patterns on the etching position, and finally use the probe to Scan the needle on the surface of the sample to check the etching results, specifically: use the tapping mode of the atomic force microscope to record the structural information of the sample surface in the selected area, and then determine the position to be etched in this area; at the etching position Fixed-point deposition is performed on the surface of the sample, and the modified tip contacts the selected position on the sample surface, so that the material adsorbed on the tip is transferred to the corresponding position, thereby realizing the manufacture of nano-patterns; switch the force curve mode back to the tapping mode, and The originally selected area is scanned to obtain the surface structure information of the sample and check the etching result.

The atomic level flat substrate is mica, graphite or silicon wafer.

The surface of the mica is hydrophobized by 3-aminopropyl silane.

The nanometer surface refers to: a flat surface, a surface adsorbed with nanoparticles, nanowires, nanobelts, nanotubes or nanosheets, and a surface etched with regular patterns.

The needle tip is a single probe or a probe array of an atomic force microscope.

The inorganic salt solution refers to an ion aqueous solution composed of potassium, sodium, magnesium, calcium, zinc or ammonium ions as cations and halogen ions, carbonate ions, sulfate ions or phosphate ions as anions.

The organic small molecule solution refers to: mercaptan or siloxane with a molecular weight less than 10,000, and the solvent is water or an organic solvent.

The colloidal solution refers to a solution formed by uniformly dispersing nanoparticles of metal gold, metal silver, metal platinum, titanium dioxide, zinc oxide or iron oxide and quantum dots in water or an organic solvent.

Compared with the existing technology, this method is not only applicable to almost all substrate materials, but also can accurately control the force and action time between the needle tip and the substrate, which can better control the etching result and improve the repeatability of the etching operation ; At the same time, the method can perform multi-point automatic positioning and dip-pen etching operations at one time, which is simple, practical and beneficial to industrialization.

Description of drawings

Figure 1 is a schematic diagram of the steps of the present invention.

Fig. 2 is a graph showing the relationship between the force curve collected by the present invention and the reflection signal of the probe (deflection signal) versus time.

Fig. 3 is a nano-dot fabricated on a silicon wafer using the present invention.

Fig. 4 is a nano lattice fabricated on a mica sheet using the present invention.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

Etching is carried out in an environment with a relative humidity of 78% to 85% using an NSC-18 needle tip. The force used was 20nN, the sample was a silicon wafer treated with hexamethoxydisilane, and the ink was glycerin. Adjust the TRIGGER TRESHOLD until the force curve shown in Figure 2A appears. If a force curve with a complete shape cannot be obtained, no matter how long the contact time is, the etching cannot be successful. It can be seen from Figure 2B that the SURFACE DELAY time between point 3 and point 4 is 1s.

Example 2

Etching is carried out in an environment with a relative humidity of 78% to 85% using an NSC-18 needle tip. The force used is 20nN, the sample is a silicon wafer after silane hydrophobic treatment, and the ink is glycerin. Points obtained by precisely controlling the residence time of the needle tip on the sample surface for 10 seconds. FIG. 3A is the pattern on the surface of the silicon wafer before etching, and FIG. 3B is the pattern after etching. Comparing the two figures, it can be seen that under this condition, the method can successfully realize the etching of nano-dots.

Example 3

Etching is carried out in an environment with a relative humidity of 43.4% to 46.5% using NSC-11 needle tips. Figure 4A shows that the force used is 40nN, the sample is newly dissociated mica, the ink is glycerin, the residence time of the needle tip on the sample surface is precisely controlled to 20 seconds, and a nano-pattern with an interval of 400nm is obtained. Figure 4B is the force used 80nN, the sample is newly dissociated mica, the ink is horseradish peroxidase, and the residence time is 30 seconds, the obtained "口"-shaped nano-dot matrix. Comparing the two figures, it can be seen that the nanodot array can be successfully obtained by this method; and because the force and time are well controlled, the shape and size of these dots are very consistent under the same operating parameters.

Claims (9)

1. the nanometer lithographic method that dips in based on the power modulating mode is characterized in that, may further comprise the steps:

The first step, in substrate, construct Nanosurface by spin coating, evaporation drying, photoetching technique, soft lithographic technique, electron beam lithography technology or ion beam etching technology, obtain sample with nanostructured at the substrate surface of atomically flating;

Second goes on foot, probe is immersed in inorganic salt solution, organic molecule solution, colloidal solution or the biological macromolecule solns takes out, and dries up;

The environment temperature of the 3rd step, control AFM is 4 ℃ to 80 ℃, and ambient humidity is that 30%RH is between the 80%RH;

The 4th goes on foot, has with probe scanning after the modification and record the sample surface information of nanostructured with selected one or more etchings position, then on the etching position with same probe structure nano graph, scan with check etching result at sample surfaces with this probe at last.

2. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1 is characterized in that the substrate of described atomically flating is mica, graphite or silicon chip.

3. the nanometer lithographic method that dips in based on the power modulating mode according to claim 2 is characterized in that, the surface of described mica is carried out hydrophobization through 3-aminopropyl silane and handled.

4. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1, it is characterized in that described Nanosurface is meant: even curface, the surface that is adsorbed with nano particle, nano wire, nanometer band, nanotube or nanometer lamella and the surface that is etched with regular pattern.

5. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1 is characterized in that described needle point is the single probe or the probe array of AFM.

6. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1, it is characterized in that, described inorganic salt solution is meant: cation is potassium, sodium, magnesium, calcium, zinc or ammonium radical ion, and anion is the deionized water solution that halide ion, carbanion, sulfate ion or phosphate anion are formed.

7. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1 is characterized in that described organic molecule solution is meant: molecular weight is less than 10000 mercaptan or siloxanes, and solvent is water or organic solvent.

8. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1, it is characterized in that described colloidal solution is meant: the nano particle of metallic gold, argent, metal platinum, titanium dioxide, zinc oxide or iron oxide and quantum dot are dispersed in the solution that forms in water or the organic solvent.

9. the nanometer lithographic method that dips in based on the power modulating mode according to claim 1, it is characterized in that, selected one or more etchings position described in the 4th step is meant: with the structural information of the sample surfaces that raps the selected zone of mode record of AFM, need to determine the position of etching again in this zone; Described structure nano graph is meant: the deposition of on the etching position, fixing a point, and the needle point after the modification contacts with the select location of sample surfaces, makes the material transfer that is adsorbed on the needle point to the relevant position, thereby realizes the manufacturing of nano graph; Described scanning at sample surfaces is meant: the force curve pattern is switched back the pattern of rapping, and original selected zone is scanned, obtain the sample surfaces structural information, check etching result.

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