JP2008111178A - Electrolytic polishing method, electrolytic polishing device and electrode rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and surely polish the surface of a sample by reducing the boiling of an electrolyte solution caused by the heat generation of the electrolyte solution, and at the same time, to polish not only a flat surface but also the inside of a small hole by easily, surely and automatically supplying the electrolyte solution, with respect to an electrolytic polishing method comprising electrically polishing the surface of a sample by providing an electrolyte solution between the sample and an electrode rod and applying a voltage between the sample and the electrode rod, an electrolytic polishing device, and the electrode rod. <P>SOLUTION: The electrolytic polishing method includes a step for repeatedly performing an operation generating a pulse-like pulse voltage and generating a pulse-like pulse voltage after the lapse of a break time, and a step for applying the generated pulse voltage between the tip of an electrode rod and a sample. In the electrode rod, sponge-like tip parts 12, 13 processed into various shapes are attached exchangeably to the tip of a supporting part 11. The electrolyte solution is supplied to the tip part by providing a cartridge or a sponge-like member including the electrolyte solution at the inside of the supporting part 11. Polishing is performed by incorporating the electrolyte solution into the tip part, then lightly bringing the tip part into contact with the surface of a sample and rubbing the surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electropolishing method, an electropolishing apparatus, and an electrode rod thereof in which an electrolytic solution is immersed between a sample and an electrolytic rod and a voltage is applied to electrolytically polish the surface of the sample.

  Conventionally, as an electropolishing apparatus, a direct current voltage is applied between an electrode rod and a sample to be polished, a cap-like material containing an electrolyte is put on the electrode rod, and an electric current is applied to the sample by the action of the electrolyte. There are devices that ionize, melt, and polish the surface.

  At this time, depending on the material of the sample, the surface of the sample was polished by manually switching the polarity of the DC voltage to be applied (positive to negative or negative to positive). Further, depending on the material, an AC voltage is applied to polish the surface of the sample.

  As described above, conventionally, the direct current voltage between the electrode rod and the sample is switched to a DC voltage of any polarity or, if necessary, the surface of the sample is polished by applying an AC voltage. I was doing.

  However, in the method of applying a voltage by immersing the electrolyte between the electrode rod and the sample, the electrolytic force differs depending on the electrolyte and the sample. Generally, as the applied voltage is increased, the voltage is higher than a certain voltage. In this case, the electrolysis force becomes strong, but conversely, a current also flows in the electrolyte solution itself, the electrolyte solution generates heat, boils, and the electrolyte solution does not evaporate in a short time. Conversely, when the voltage is lowered, the relationship between the voltage and the electrolysis power is not a proportional relationship, and the electrolysis power (force due to electropolishing of the surface of the sample) rapidly decreases at a certain voltage. There is a problem that the adjustment range of the obtained voltage is narrow and difficult to control.

  In addition, the electrolytic polishing apparatus only polishes the surface of the sample, and it cannot polish the dirt attached to the inside of a small Wehnelt hole (usually a hole of about 1 mmφ) constituting an electron gun used in an electron microscope or the like. There was also.

  In order to solve these problems, the present invention provides an electrode rod that intermittently applies a pulse voltage and automatically replenishes the electrolyte in an electrolytic polishing apparatus in a state where the electrolyte is immersed between the electrode rod and the sample. The tip shape can be changed to various ones) for polishing.

  According to the present invention, in an electropolishing apparatus, an optimum electrolysis can be achieved by providing an electrode rod that intermittently applies a pulse voltage while the electrolyte solution is immersed between the electrode rod and the sample and automatically supplies the electrolyte solution. The surface of the sample is polished easily and reliably, the electrolyte solution is easily and surely replenished, and the tip of the electrode rod has various shapes. By making it replaceable, not only a flat surface but also the inside of a small hole can be polished.

  According to the present invention, in an electropolishing apparatus, an electrode rod that intermittently applies a pulse voltage with an electrolytic solution immersed between an electrode rod and a sample and automatically replenishes the electrolytic solution is provided to obtain an optimum electrolytic power. At the same time, the boiling due to heat generation of the electrolyte is reduced, the surface of the sample is polished easily and reliably, the electrolyte is automatically and reliably replenished, and the tip of the electrode rod can be replaced with various shapes As a result, it was possible to polish not only flat surfaces but also the inside of small holes.

FIG. 1 shows a system configuration diagram of the present invention.
In FIG. 1, a power source 1 generates a DC power source. Here, a power source 1 generates and outputs a predetermined DC voltage (for example, 20 VDC) designated by the control circuit 4.

  The switches 2 and 3 are semiconductor (IC) switches, select a positive or negative DC voltage from among the DC voltages of a predetermined voltage output from the power supply 1, repeat energization for a predetermined time, and pause for a predetermined time. A positive or negative pulse voltage is generated and applied between the sample 8 and the electrode rod 6 (see FIG. 2).

  The control circuit 4 controls the voltage value of the pulse voltage applied between the sample 8 and the electrode rod 6, the pulse width, and the repetition period (number of circulators). The power supply 1 and the switches 2 and 3 are controlled to perform the following control so as to generate a pulse voltage in accordance with a user instruction from the touch panel and keyboard.

・ Pulse voltage polarity (positive, negative, alternating positive and negative, alternating every arbitrary number of positive and negative):
・ Pulse voltage: For example, 20VDC
・ Pulse width of the pulse voltage: Any value within a range of, for example, 10 to 50% of a duty ・ Repetition period (frequency, pause period) of a pulse voltage: Any value such as a repetition frequency of 1 to 5 hertz ・ Others: Overcurrent protection and its value
The polarity of the pulse voltage is such that the pulse voltage applied to the electrode rod 6 with respect to the sample 8 is a positive pulse voltage, a negative pulse voltage, a positive pulse and a negative pulse voltage are repeated alternately, positive and negative. The polarity can be selected for any number of alternating repetitions for any number of pulse voltages (the user can select one from the outside (or set by default)).

  The pulse voltage is a voltage value of the pulse voltage generated by the power source 1 and applied to the electrode rod 6. If the pulse voltage is too low, the electrolysis power (electrolytic polishing power of the sample 8 by the electrolytic solution) is too weak, and if it is too high, electrolysis is performed. Although the force becomes stronger, current flows in the electrolyte itself and heats up and boils, causing the electrolyte to evaporate and disappear, so the electrolyte is moderately strong and the electrolyte is boiled and short. The voltage value of the appropriate pulse voltage that does not disappear in time can be adjusted (the user can appropriately adjust (or set by default) by looking at the electrolytic power and the boiling state of the electrolytic solution from the outside).

  ・ The pulse width of the pulse voltage is adjusted by the switches 2 and 3 (semiconductor elements). The pulse width of the pulse voltage of a predetermined polarity is adjusted by the user (seeing the electrolytic power, the boiling state of the electrolyte, especially the boiling state from the outside. It can be adjusted moderately (or set by default).

  -The repetition period (frequency, pause period) of the pulse voltage is adjusted by the switches 2 and 3 (semiconductor elements), and the repetition period of the pulse voltage with a predetermined polarity is adjusted (the user can externally apply electrolytic power, the boiling state of the electrolyte, In particular, the state of removal of adhering matter and dust on the surface of the sample 8 (the adhering matter cannot be removed if the repetition period is slow, and the adhering matter cannot be removed even if it is too fast, so the adhering matter is removed moderately during that period (normally Can be adjusted (or set by default)).

  -The presence or absence of other overcurrent protection and its value are determined by supplying a pulse voltage to the electrode bar 6 and overpowering the user with too much force when tracing the place where the sample 8 is to be polished. It is possible to adjust (set by default) the protective control and reset, such as performing current limiting (or temporarily interrupting current) when current flows.

  The adjustment circuit 5 is an adjustment circuit (volume) that allows the user to adjust (or set by default) the voltage value of the pulse voltage, the pulse width of the pulse voltage, the repetition period (frequency, pause period) of the pulse voltage, and the like. Or a volume adjustment image displayed on the screen).

The electrode bar 6 is an electrode bar for applying a pulse voltage (see FIGS. 3 to 6).
The tip 7 has a sponge-like rod shape soaked with an electrolytic solution and has a shape such as a rounded, sharpened, or thinned tip (see FIGS. 3 to 6). Since the Wehnelt hole constituting the electron gun of the electron microscope is usually about 1 mmφ, the contamination attached to the inside of the hole is removed by making it slightly narrower than this. Further, when removing unnecessary deposits or the like adhering to a column or a flat part in a vacuum vapor deposition apparatus, an ion sputtering apparatus or the like, the tip part 7 having a flat tip and slightly rounded tip is easily polished. In addition, it is possible to greatly improve the workability of polishing by gently touching and tracing the portion to be polished with the tip of the shape suitable for the shape to be polished (plane, bar, hole, etc.).

  The sample 8 is a sample to be electropolished, for example, a sample to be observed such as an electron microscope or an optical microscope, and a portion to which unnecessary substances are attached by the above-described vacuum evaporation apparatus, ion sputtering apparatus, or the like, that is, polishing. This is the part to be cleaned (the part of the column, flat part, bell jar, etc.).

  Next, generation of a pulse voltage applied to the electrode rod 6 in the configuration of FIG. 1 will be described in detail using the waveform diagram of FIG.

FIG. 2 shows a waveform diagram of the present invention.
FIG. 2A shows an example of a + control waveform. The pulse voltage having the + control waveform shown in the figure is generated when the switch 2 is in a conductive state only during the pulse control time Δt with respect to the + power DC voltage generated from the power supply 1 in FIG. As shown in the figure, the pulse voltage is a waveform obtained by repeating a pulse voltage having a width of the pulse control time Δt with a repetition period T. The pulse control time Δt is arbitrarily adjusted (usually adjusted within the range of 10 to 50% duty) between the maximum pulse width Δtmax shown in the figure and the minimum pass width Δtmin not shown in the figure.

  FIG. 2B shows an example of a -control waveform. The pulse voltage having the control waveform shown in FIG. 1 is generated when the switch 3 is in a conductive state only during the pulse control time Δt with respect to the DC voltage generated from the power source 1 in FIG. As shown in the figure, the pulse voltage is a waveform obtained by repeating a pulse voltage having a width of the pulse control time Δt with a repetition period T. The pulse control time Δt is arbitrarily adjusted (usually adjusted within the range of 10 to 50% duty) between the maximum pulse width Δtmax shown in the figure and the minimum pass width Δtmin not shown in the figure.

  FIG. 2C shows an example of an alternating waveform. The pulse voltage having the alternating waveform shown in the figure is a pulse voltage obtained by alternately repeating the waveforms shown in FIGS. 2 (a) and 2 (b). In addition, although the pulse voltage shown in the figure is generated by alternately generating positive and negative polarity pulse voltages, the present invention is not limited to this, and a predetermined number of positive pulse voltages and a predetermined number of negative pulse voltages are specified (samples). The user may observe the state of polishing No. 8 and adjust it to an optimum value (or set as a default)), and repeat these steps.

  As described above, a pulse voltage having a predetermined repetition period T with a predetermined pulse width Δt can be generated based on the DC voltage (+, −) generated by the power source 1 and supplied to the electrode rod 6. At this time, as described above, the voltage value V, the pulse width Δt, and the repetition period T of the pulse voltage are arbitrarily adjusted (or arbitrarily set by default) from the outside using the adjustment circuit 5 of FIG. Is possible.

FIG. 3 shows an explanatory diagram (part 1) of the present invention.
FIG. 3 (a) shows an overall configuration diagram in which a cotton swab 12 or the like containing an electrolytic solution is attached to the tip of the tweezers 11. In the illustrated example, the tip of a commercially available tweezer 11 is cut and processed, as shown in (b-1) of the enlarged view, so that the swab 12 and the like can be easily grasped.

FIG. 3B is a schematic diagram in which the tip portion of the tweezers 11 is enlarged.
FIG. 3B-1 schematically shows an enlarged state of the tip of the tweezers 11 of FIG.

  (B-2) of FIG. 3 schematically shows a state in which the tip portion of a commercially available cotton swab 12 is cut (it may not be cut and it may be difficult to handle as it is). The user inserts the shaft portion of the illustrated swab 12 into the enlarged tip portion of the tweezers 11 shown in FIG. Then, the part of the swab 12 is immersed in an electrolyte solution (not shown) (neutral, acidic, alkaline (electrolyte solution having an acidity suitable for electrolysis depending on the material of the sample 8 to be electropolished)), and included. When lightly touching and rubbing the corresponding part of the sample 8 to be electropolished, a predetermined voltage pulse flows into the part where the sample 8 is in contact with the electrolytic solution and the electrolytic solution is immersed in the electropolishing, and the electrolytic solution generates a little heat to generate convection (or slightly Bubbles are continuously generated), and the dust is removed and beautifully polished. When the electrolytic solution runs out or the cotton swab 12 is stained black with dirt or contaminants, the cotton swab 12 is replaced with a new cotton swab 12, and the cotton swab 12 is used in a disposable manner.

  FIG. 3B-3 shows an example of a felt-like object. The felt-shaped one shown is an alternative to the cotton swab 12 of FIG. 3 (b-2). Similarly, it is attached and contains an electrolytic solution, and lightly touches the corresponding part of the sample 8 to be electropolished. When rubbed, a predetermined voltage pulse comes into contact with the sample 8 and flows into the part where the electrolyte is immersed, and the electrolytic polishing and the electrolyte generate a little heat and convection (or some bubbles are continuously generated) to remove dust. And so to speak, it will be polished.

  As described above, the tip of the tweezers 11 is processed, the cotton swab 12 or the felt-like member 13 is held at the tip, and the sample 8 is lightly touched and rubbed with the electrolyte solution. It is possible to remove the dust in the corresponding part and clean it by electrolytic polishing, and easily generate a sample surface such as an electron microscope or an optical microscope. Then, if necessary, it is replaced with a new cotton swab 12 or the like, and the surface of the sample 8 is always polished with a clean cotton swab 12 so that the surface of the sample 8 appears clean.

  FIG. 4 shows an explanatory diagram (part 2) of the present invention. The electrode rod 21 shown in FIG. 3 holds the cotton swab 12 by processing the tip of the tweezers 11, and instead of containing the electrolyte solution in the cotton swab 12, a chucking portion 22 is provided to the chucking portion 22. The example which fixed cotton swab 23 etc. is shown.

  4A, a chucking portion 22 is provided at the tip of the electrode rod 21, and the right end (rear end) portion of the electrode rod 21 is pressed down to open the chucking portion 22 and fix the cotton swab 23. FIG. The structure is shown schematically.

  FIG. 4B shows an example of a cotton swab 23. The illustrated cotton swab 23 is inserted into a chucking portion 22 provided at the tip of the electrode rod 21 shown in FIG.

  FIG. 4C shows an enlarged schematic diagram of the chucking portion 22. Here, the shaft core of the cotton swab 23 in FIG. 4B is inserted into the chucking portion 22 and fixed as shown.

  FIG. 4D shows an example of felt. The felt 24 shown in the figure shows another example in which the felt 24 is inserted into the chucking portion 22 at the tip of the electrode bar 21 and fixed instead of the cotton swab 23 in FIG.

  As described above, the shaft core or felt 24 of the cotton swab 22 is inserted and fixed to the chucking portion 22 provided at the tip of the electrode rod 21, and the sample 8 is lightly touched and rubbed with the electrolyte solution. It is possible to clean the corresponding portion of the sample 8 by removing the dust and electrolytic polishing, and to easily generate a sample surface such as an electron microscope or an optical microscope.

FIG. 5 shows an explanatory diagram (part 3) of the present invention.
5A, instead of providing the chucking portion 22 at the tip portion of the electrode rod 21, the electrode rod 31 of FIG. 5A is a folder (two locations) with a slightly strong force 33. (There is a portion that has a slit and slightly expands.) An example in which an object fixed by being pushed into 34 is inserted and fixed at the tip of the electrode rod 31 is schematically shown. The grip portion of the electrode rod 31 is an electrolytic solution container 32. The electrolytic solution is filled inside, and the electrolytic solution exudes moderately into the felt 33 inserted and fixed (the electrolytic solution is unnecessary). The valve is normally closed with a spring so that it does not flow into the valve. When the felt 33 is pushed into the inside strongly, the valve opens to cause the electrolyte to flow into the felt 33 and stop pushing the felt 33 into the inside. May be a closed structure). The cap 36 is removed when the electrolytic solution is put into the electrolytic solution container 32, and is inserted and fixed after the electrolytic solution is put.

FIG. 5B schematically shows a state where the felt 33 is attached to the folder 34.
FIG. 5C schematically shows a state in which the cotton swab 35 is attached to the folder 34. As shown in FIG. 5A, the felt 34 and the cotton swab 35 attached to the folder 34 in FIGS. 5B and 5C are moved from the left side to the right side by a strong force from the tip of the electrode bar 31. By inserting, it becomes possible to attach the felt 34 and the cotton swab 35 to the electrode rod 31 and to contain an appropriate electrolyte from the electrolyte container 32.

  As described above, the felt 33 and the cotton swab 35 attached to the folder 34 at the tip of the electrode rod 21 are inserted with a strong force in the right direction from the left tip of the electrolytic rod 31 and attached. The sample 8 is lightly touched and rubbed to remove the dust from the corresponding part of the sample 8 and clean it by electrolytic polishing to easily generate a sample surface such as an electron microscope or an optical microscope. It becomes possible to polish the inside of the small hole of Wehnelt cleanly.

FIG. 6 is an explanatory diagram (part 4) of the present invention.
FIG. 6A schematically shows a state in which the cotton swab 12 is sandwiched between the tip portions of the tweezers 11 of FIG. 3A described above and the cotton swab 12 is lightly touched and rubbed against the metal sample 8. As shown in the drawing, the distance between the tip of the tweezers 11 and the metal sample 8 is always kept substantially constant at a predetermined distance L, and when a pulse voltage is applied, an electrolytic action caused by passing a current, A slight amount of current flows through the electrolyte itself to generate heat and the temperature of the electrolyte increases, and a small amount of small bubbles are continuously generated. As a result, the electrolyte solution 14 has a cotton swab 12 and a metal sample 8 as illustrated. And the dust is lifted from the surface of the metal sample 8 by the small bubbles and removed, and is electropolished to clean the portion of the metal sample 8 that is filled with the electrolytic solution 14. Experiments have shown that reproducibility can be greatly improved by keeping the distance L substantially the same. In order to keep the distance L substantially the same, although not shown in the figure, a non-conductive rod having a length of the distance L is provided between the tip of the tweezers 11 or another portion and the metal sample 8. A structure for keeping the distance constant may be provided.

FIG. 6B shows an example of the shape of the tip of the cotton swab 12.
6B-1 shows an example in which the tip of the swab 12 is sharpened as shown, and FIG. 6B-2 shows an example in which the tip of the swab 12 is rounded as shown in FIG. (B-3) shows an example in which the tip of the cotton swab 12 is thinned and sharpened as shown in the figure. The tip of these cotton swabs 12 is sharpened, rounded, thinned, sharpened, and when the state shown in FIG. Select by.

  Although FIG. 6A illustrates the case where the sample 8 is flat, the contamination adhered inside the small Wehnelt hole (about 1 mmφ) constituting the electron gun of the electron microscope is further polished and removed. To do this, as shown in Fig. 6 (b-3), apply a voltage pulse by making the tip of the electrode rod 6 narrow and slightly long and rotating it lightly with the tip fully inserted into the hole (about 1 mmφ). By doing so, the inside of the hole can be polished over the entire surface. Then, instead of immersing the electrolyte, insert another cotton swab 12 soaked with a cleaning solvent into the hole and rotate it lightly to remove residual polishing liquid after polishing and clean it. It becomes possible to clean it.

  According to the present invention, in an electropolishing apparatus, an electrode rod that intermittently applies a pulse voltage with an electrolytic solution immersed between an electrode rod and a sample and automatically replenishes the electrolytic solution is provided to obtain an optimum electrolytic power. At the same time, the boiling due to heat generation of the electrolyte is reduced, the surface of the sample is polished easily and reliably, the electrolyte is automatically and reliably replenished, and the tip of the electrode rod can be replaced with various shapes Thus, the present invention relates to an electropolishing method, an electropolishing apparatus, and an electrode rod thereof that polish not only a flat surface but also the inside of a small hole.

It is a system configuration diagram of the present invention. It is a wave form diagram of the present invention. It is explanatory drawing (the 1) of this invention. It is explanatory drawing (the 2) of this invention. It is explanatory drawing (the 3) of this invention. It is explanatory drawing (the 3) of this invention.

Explanation of symbols

1: power supply 2, 3: switch 4: control circuit 5: adjustment circuit 6, 31, 31: electrode rod 7: tip 8: sample (metal sample)
11: Tweezers 12, 23, 35: Cotton swabs 13, 24, 33: Felt 22: Chucking part 32: Electrolyte container 36: Cap

Claims (9)

In an electropolishing method in which an electrolytic solution is immersed between a sample and an electrolytic rod and a voltage is applied to electropolish the surface of the sample,
Generating a pulsed pulse voltage and repeatedly generating a pulsed pulse voltage after the rest period has elapsed;
Supplying the generated pulse voltage between the electrolytic rod and the sample.   2. The electrolytic polishing method according to claim 1, wherein the polarity of the pulse voltage is alternately repeated positively and negatively, or alternately alternately positively and negatively every arbitrary number.   The first adjustment circuit for adjusting the width of the pulse voltage is provided, and the user can adjust the first adjustment circuit to be adjusted to an optimum electrolytic polishing state. 2. The electrolytic polishing method according to 2.   A second adjustment circuit for adjusting the pause period, the repetition period of the pulse voltage or the repetition frequency of the pulse voltage is provided, and the user can adjust the second adjustment circuit to adjust to the optimum electropolishing state. The electrolytic polishing method according to any one of claims 1 to 3, wherein:   The third adjustment circuit for adjusting the voltage of the pulse voltage is provided, and the user can adjust the third adjustment circuit to adjust to an optimum electrolytic polishing state. 4. The electrolytic polishing method according to any one of 4 above.   6. The electrolytic polishing method according to claim 1, wherein the frequency of the pulse voltage is set within a range of 1 to 5 hertz.   The electrode rod is attached to the tip of the rod-like support part with a sponge-like electrolyte-containing sponge, the rod-like tip is rounded, the tip is sharpened, or the tip is narrowed, with a replaceable mechanism. The electrode rod used for the electropolishing method according to any one of claims 1 to 6, wherein the electrode rod is used.   A cartridge containing an electrolytic solution or a sponge-like member immersed in the electrolytic solution is provided inside the support portion, and the electrolytic solution is supplied from the cartridge or member to the replaceable rod-shaped tip. An electrode rod used in the electropolishing method according to claim 7. In an electropolishing apparatus for electrolytically polishing the surface of the sample by applying a voltage by immersing an electrolyte between the electrolytic rod and the sample,
A circuit that generates a pulsed pulse voltage and repeats generating a pulsed pulse voltage after a pause period has elapsed,
An electropolishing apparatus characterized in that a pulse voltage generated in the circuit is supplied between the electrolytic rod and a sample to electropolish the surface of the sample.

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