JPH01205939A - Manufacture of needle - Google Patents

Abstract

PURPOSE:To obtain the simple method for manufacturing needles in a wide application range by etching-treating a metal wire on which a deformed or broken part is formed, on the surface of an electrolytic liquid or in the electrolytic liquid. CONSTITUTION:After a metal wire 1 is inserted into a tube 3, a deformed or broken part 2 is formed on the metal wire 1, and then said wire 1 is etching- treated in an electrolytic liquid. Then, the wire is surely cut at the deformed or broken part 2. Since a formed needle projects by several mm from the top edge of an insulating tube 3' in the lower part, said needle can be easily taken out. The reason of the formation of the needle at the deformed or broken part 2 comes from the fact that this part is made thinner in comparison with the diameter of the original wire, and etching is completed faster, or the surface area of the etching-treated part is increased, and the etching rate is increased.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is directed to a scanning tunneling microscope (Scanning Tube).
This invention relates to a method for manufacturing a metal needle that serves as a sensor when analyzing and evaluating surface irregularities of objects, atomic attraction force, magnetic attraction force, etc. by applying the principle of ``Nneling Mieroseopy''.

<Prior Art> There are various methods for producing needles for sensing tunneling current, atomic attraction, magnetic attraction, and the like. Among these, a relatively simple method of obtaining a needle tip of about 1 μm is a method of etching on the surface of or in an electrolytic solution. The features of this method are as follows: (1) The tip that falls into the electrolyte as a result of etching is sharp, and is therefore used as a needle.

(2) Insulate the parts that will not be etched with tubes, etc., and limit the etched parts.

These are P, J. Bryant, et al=Re
v,sci,In5tru,.

vol, 58. , p. 1115.1987. and Expenses, Kaneko; Proceedings of the 48th Academic Conference of the Japan Society of Applied Physics, No. 20P-B-9, P, 396.198
7° is described in the literature.

<Problem to be solved by the invention> However, especially when sensing atomic attraction force or magnetic attraction force, since the weak force of atomic attraction force or magnetic attraction force is detected as deformation i such as deflection of the needle, The diameter of the needle itself is required to be small, for example 0.1 mm or less. In this case, with the above method, there is no good way to insulate the wire and recover it easily after needle formation because the diameter of the wire is small.■ If etching is performed at a high current density, air bubbles will be generated and etching will be interrupted if the tube spacing is reduced. There were problems such as non-uniformity, loss of reproducibility when the tube spacing was widened, and difficulty in handling such as collection due to the small wire diameter.

The present invention was made in view of the above situation, and an object of the present invention is to provide a needle manufacturing method that is simple and has a wide range of applications.

Means for Solving the Problems> In order to achieve the above object, the method for manufacturing a needle of the present invention involves deforming or scratching a part of a metal wire, and placing the deformed or scratched metal wire on the surface of an electrolyte. Alternatively, the needle is produced by etching in an electrolytic solution. Also,
The method is characterized in that the metal wire is covered with an insulator except for deformed or damaged areas, and the metal wire is etched on the surface of or in the electrolytic solution to produce the needle.

Function: When a metal wire is etched, it becomes thinner from the deformed or scratched area, and the metal wire is fused to create a needle tip.

Examples: Figure 1 shows the appearance of the metal wire, Figure 2 explains the state of etching, Figure 3 shows the current-voltage characteristics of Fe and Ni wires, and Figure 4 shows the constant current drive. This figure shows the change in melting time over time.

In Figure 1, 1 is a metal wire, 2 is a deformed or uneven part provided on the metal wire 1, 3 is a tube as an insulator, 4 is a buoyancy generating means, and 5 is a tube interval (non-insulated part)
The tube spacing 5 is set in a range of 11 to several. Tube 3 is a heat shrink tube with an inner diameter of 0.5m+a (
Stretch the Shunflon wire with heat to an inner diameter of 0.2 to 0.3 m.
The tube 3 is passed through the metal wire 1 using a piece of metal wire 1 as an insulator, which has a size of about 100 mm. After passing through the tube 3, the metal wire 1 is provided with a deformed or biased portion 2. When forming the deformed or eccentric portion 2, conventional cutting means are used, such as nippers, scissors, a utility knife, a razor blade, etc.

The degree of deformation or uneven portion 2 can be determined by making a small notch in the blade of a nipper or the like, by applying the blade to a spacer whose thickness is known in advance, or by controlling the force applied to the cutting.

This metal wire 1 is etched in an electrolytic solution as shown in FIG. In Figure 2, part A is a deformed or scratched wire part, 6 is a platinum electrode, 7 is a constant current or constant voltage power source, and 8 is an electrolyte, in this case hydrochloric acid (HCI) with a concentration of 10%.
, 9 is the bee force. This method is used because the tip of the needle will be sharper if it falls due to etching. FIG. 3 shows the voltage-current characteristics of Fe and Ni wires. FIG. 4 shows the time taken to complete etching when driven at constant current. Under these conditions, a sharp needle with a tip diameter of about 1 μm was obtained in the current range of 20 to 50 mA.

If the metal wire 1 does not have the deformed or eccentric part 2, the part not covered by the tube 3 will be rapidly etched, and the needle part will enter the lower tube 3' and be difficult to remove. On the other hand, when the deformed or biased portion 2 was attached, the deformation or biased portion 2 was surely cut. The needle formed in the four parts 2 of this modified t-t1 protrudes from the upper end of the lower insulating tube 3' by several millimeters, so it is easy to take out.

The reason why needles are formed in the deformed or uneven part 2 is thought to be that this part becomes thinner than the original wire diameter, so etching completes quickly, or that the etching rate is high because the surface area of the part to be etched increases. Let it go. Note that if the insulating tube is not provided, deformation or melting may occur from areas other than the uneven portion 2. By insulating with the insulating tube 3, it was possible to ensure that the metal wire 1 was deformed or fused at the uneven portion 2. This is thought to be because etching depends on the surface thickness of the part to be etched.

The buoyant force applying means 4 is made of polystyrene foam, and is set so that the gravity of the part to be cut is slightly larger than the buoyant force. This is because the tensile force on the needle-shaped acid part is weakened when etching is completed (during fusing), allowing sufficient etching to reach the tip, and at the same time, the tip of the needle stands in the electrolyte after falling, so the needle It is useful for facilitating handling such as collection without being subjected to disturbances such as deformation and bending after formation. However, even in the absence of the buoyancy applying means 4, the needle falls almost freely in the electrolyte, so the sharpness of the needle is the same as in the case without the buoyancy applying means.

Figure 5 shows the tip (needle) of the metal wire 1 that has been fused.
In the case of Fe, Fig. 5+81 shows the shape of Fig. 5 (
bl shows the case of Ni. As shown in Figure 5 (rL), in the case of Fe, the tip may become like the tip of a pen reflecting the deformation, but as shown in Figure 5 (b), in the case of Fe,
In this case, the tip of the needle is as sharp as at least 1 μm or less.

Furthermore, since the non-insulated portions are also etched, they become thinner in a substantially --shape as shown by the reference numeral 20 in FIG. 5(fl). FIG. 5 is a graphical representation of the results of optical @ microscopic observation, and in this example, the thickness of 9 is as thin as about 1/3.

In the above-described needle manufacturing method, the metal wire 1 is deformed or a vortex portion 2 is added, and that portion is selectively etched to become the needle tip. In addition, since the part other than the deformed or uneven part 2 was covered with the chinibu 3, the non-insulated part (the deformed or uneven part 2
) will be etched to make the wire thinner. Furthermore, since the buoyancy generating means 4 is provided at the fusing part, the fusing is completed slowly and the needle can be recovered easily.

It is obvious that the method of the present invention can be applied to ordinary tunnel current detection, atomic attraction force measurement, and to the production of needles for field emission microscopes.

<Effects of the Invention> In the needle manufacturing method of the present invention, the metal wire is deformed or damaged, and the deformed portion is selectively etched to become the needle tip. Also, since the necessary portions are covered with an insulator, the non-interrupted portions will be etched to become thinner lines.

This results in a new manufacturing method that is simple and has a wide range of applications.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are side and front views of the metal wire according to the present invention, Figure 2 is an explanatory diagram of the state in which etching is being performed, and Figure 3 is the current and voltage of the Fe wire and Ni wire. A graph showing the characteristics, Fig. 4 is a graph showing the change in fusing time during constant current driving, Fig. 5 (a) is a plan view showing the tip (needle part) of the fusing Fe wire,
FIG. 5 1b) is a plan view showing the tip portion (needle portion) of the fused Ni wire. In the drawing, 1 is a metal wire, 2 is a deformed or uneven part, 3.3' is a tube, 4 is a buoyancy generating means, 5 is a tube spacing, 6 is a platinum Ti electrode, 7 is a constant current or constant voltage power source, 8 is the electrolyte, and 9 is the pea force.

Claims (1)

[Claims] 1. A needle is produced by deforming or scratching a part of a metal wire and etching the deformed or scratched metal wire on or in the electrolyte. How to make needles. 2. The method for manufacturing a needle according to claim 1, wherein the metal wire is covered with an insulator except for deformed or damaged areas.