JP3875907B2 - Fine processing method and fine processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a micromachining technique using abrasive grains, and more particularly to a micromachining method and a micromachining apparatus capable of finishing a fine shape and a finely machined portion having a complex shape into a high-quality surface.
[0002]
[Prior art]
With the progress of semiconductor manufacturing technology, the fine processing technology that has grown to a high degree has come to be required for the manufacturing process of advanced industrial products. However, since the microfabrication technology requires a clean room on the production line and uses a more expensive semiconductor manufacturing apparatus, initial investment and operation and maintenance costs are factors that increase the product price and have an environmental impact. However, the creation of useful technologies capable of eliminating these and the microfabrication technology for leading to inexpensive products have not been provided so far. When the sample is glass, processing with a diamond tool is appropriate, but the diamond tool is also expensive as a tool. Therefore, there is a present situation that a fine tool has not yet been provided.
[0003]
[Problems to be solved by the invention]
An apparatus for processing an abrasive grain held by a micro tool under an AC high-voltage electric field can provide a micro-processing apparatus that can be made compact. In other words, since the processing environment and incidental equipment can be suppressed from the method of maintaining the entire room with a good cleanliness to the surrounding area where the apparatus is placed, it is an environment-friendly micro-processing method.
[0004]
[Means for Solving the Problems]
The present invention has been proposed in view of the above, and a non-contact in which a fine tool having a spherical tip is used as an electrode and the other electrode is disposed below the workpiece, and the tip of the fine tool and the workpiece are brought close to each other. A silicone oil having a viscosity of 1 to 1,000 cSt at 20 ° C. is used as the main component of the solvent, and abrasive particles having an electric dielectric property with a particle size of 0.1 to 30 μm are placed in this solvent. Dispersed liquid composition is disposed, and the fine tool is rotated at a high speed while the abrasive grains are oriented while applying an AC electric field with an electric field strength of ± 0.3 to 5 kV / mm and a frequency of 0.1 to 100 Hz. It is a fine processing method characterized by rolling and processing abrasive grains.
In particular, at first, an AC high voltage with a high frequency of 20 Hz or more and 100 Hz or less is applied, and after adjusting the position of the fine tool and the surface of the workpiece, the applied frequency is changed to 0.1 to 20 Hz and the fine tool is operated at high speed A rotating method is desirable.
[0005]
Further, the present invention attaches a fine tool having a spherical tip to the Z-axis table as an electrode and the other electrode as an XY axis table, and the tip of the fine tool is not in contact with the XY axis table. The main component of the solvent is 20 ° C. between the workpiece placed on the XY axis table and the tip of the fine tool. A silicone oil having a viscosity of 1 to 1,000 cSt and a liquid composition in which abrasive grains having an electric dielectric property with a particle diameter of 0.1 to 30 μm are dispersed in this solvent are supplied, and an electric field strength of ± The present invention also proposes a microfabrication apparatus that can perform microfabrication by applying and controlling an alternating electric field of 0.3 to 5 kV / mm and a frequency of 0.1 to 100 Hz.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The liquid composition used in the present invention comprises the following solvent and abrasive grains. As a solvent, a silicone oil having a viscosity of 1 to 1,000 cSt at 20 ° C. is used as a main component. The abrasive grains are insulating particles and semiconductor particles having an electrical dielectric property with a particle size of 0.1 to 30 μm, and those having a particle size smaller than that according to the processing width (1 to 50 μm). As for the electrical dielectric properties of the abrasive grains, it is desirable that the relative dielectric constant of the abrasive grains be one or more larger than the relative dielectric constant of the solvent. As a result, a force is developed (induced) in the abrasive grains by the electric field gradient applied in the liquid composition. As the abrasive grains, workability (polishing / grindability) is required, so that the hardness thereof is equal to or higher than the hardness of the workpiece, or has a mechanochemical action with the workpiece. . Specifically, diamond, corundum, emery, garnet, silica, calcined dolomite, fused alumina, artificial emery, silicon carbide, zirconium oxide, cubic boron nitride cBN, etc. or chromium oxide or oxide used for mechanochemical polishing Examples thereof include silicon, iron oxide, calcium oxide, magnesium oxide, cerium oxide, magnesium carbide, and barium carbonate. And the said abrasive grain is mixed in the said solvent, and it is made to disperse | distribute uniformly with an ultrasonic disperser etc. to make a liquid composition.
[0007]
In addition, the AC electric field applied in the present invention is a square wave that swings positively and negatively with repetition of an electric field strength of ± 0.3 to 5 kV / mm, a frequency of 0.1 to 100 Hz, and a rise of 30 to 500 V / μsec. It is a sine wave. If the applied frequency is less than 0.1 Hz, the abrasive grains may settle. If the applied frequency exceeds 100 Hz, the abrasive grains cannot respond to the frequency and cannot move.
[0008]
The tip of the fine tool used in the present invention is used as a rotating electrode, and the material is not particularly limited. For example, a cemented carbide material such as a tungsten alloy system or a cBN material, or a brittle material having conductivity. Further, a conductive plastic, a copper alloy that advances the processing while holding the abrasive grains, and a hardened steel can be used. Further, the tip of the fine tool is formed to have a spherical shape. Further, this fine tool is used as a rotating electrode. Specifically, for example, it is desirable to attach an equipment mechanism such as an air spindle and set the rotational speed at that time to about 5,000 to 100,000 rpm.
[0009]
The other electrode with respect to the rotating electrode also serving as the fine tool is arranged at the lower part of the workpiece, and this electrode is used as an XY axis table, and the vertical direction is Z axis to control the movement of the fine tool. Anyway. The XY axis table may be a fixed electrode or a rotatable electrode.
[0010]
In order to carry out the micromachining method of the present invention using such materials and equipment, the fine tool and the work piece are arranged in a close non-contact manner, specifically the distance (Z-axis). (Distance in the direction) may be adjusted according to the processing width (0.5 to 50 μm). For the adjustment, for example, a magnifying glass is attached to a CCD camera (100 to 1000 times) and photographed from the side of the fine tool, What is necessary is just to adjust to a set distance by fine-movement adjustment of the Z-axis table which attached the fine tool integrally while projecting on a monitor. Alternatively, a laser displacement meter may be provided. Of course, the liquid composition of the said composition is arrange | positioned between a fine tool and a to-be-processed object.
When the processing shape is a concave depression, it is desirable to arrange the fine tools parallel to the Z axis (perpendicular) as shown in FIG. 2, but a linear shape with a uniform line width, etc. When forming an arbitrary recess, as shown in FIGS. 1 and 3, it is desirable that the fine tool be disposed at an angle of 10 to 80 degrees (80 to 10 degrees with respect to the Z axis). In other words, the rotation of the fine tool is such that the peripheral speed is 0 at the center position in the arrangement as shown in FIG. Then, the abrasive rolling operation by rotation can affect the whole.
[0011]
First, an AC high voltage having a high frequency of 20 Hz to 100 Hz is applied to resonate the abrasive grains in the liquid composition, and the movement between the electrodes (between the upper rotating electrode and the lower electrode) is slight. It exhibits vibration, becomes an oriented state, holds the abrasive grains at the tip of the fine tool, and is ready for processing. Here, the distance between the electrodes is narrowed by finely adjusting the Z-axis table to which the fine tool is integrally attached.
[0012]
Next, when the fine tool is rotated at a high speed and the applied frequency is changed to 0.1 to 20 Hz, the abrasive grains in the liquid composition are actively moved between the electrodes. That is, the tip of the fine tool as the rotating electrode can be finely processed while holding the abrasive grains.
In this microfabrication, the force that the abrasive grains are scattered by the centrifugal force generated by the rotation of the fine tool is also given, but the coulomb force is generated by the electric field, and the abrasive grains that are dielectric materials do not scatter and are produced by machining Only debris can be blown out of the electric field by centrifugal force. That is, it is a particularly effective processing method as a processing method that dislikes the scattering of abrasive grains.
Also, in this micromachining, the tip of the fine tool is always kept in non-contact with the workpiece, and the machining is performed by abrasive grains. Therefore, friction is applied as in the case of machining with the tool in contact with the workpiece. There is no generation of heat and finer processing can be performed.
[0013]
【Example】
The microfabrication apparatus shown in FIG. 1 is an example in which an XY axis table 1 on which a slide glass as a workpiece 2 is placed is adopted as a lower fixed electrode.
As the fine tool 4, a tungsten carbide cemented carbide (carbide WC) was used, the tip of which was formed into a spherical shape of R0.5 (diameter 1 mm), and an upper rotating electrode. The distance between the workpiece 2 and the fine tool (tip) 4 can be adjusted by the Z-axis table 6 by attaching a magnifying glass to the CCD camera.
In addition, cerium oxide that exhibits a mechanochemical effect on glass is used as abrasive grains having electrical dielectric properties, and cerium oxide having an average particle diameter of 5 to 10 μm in a concentration of 30 wt.% In a silicone oil (solvent) having a viscosity of 100 cSt. % Liquid and carefully dispersed with an ultrasonic disperser to obtain a liquid composition 3.
Note that when the XY axis table 1 is rotated, a linear motor or the like may be used, and the fine movement method may be finely moved using a piezoelectric element or the like.
Further, the θ-axis feed mechanism 7 used when performing linear groove machining as shown in FIG. 3 is fixed by giving an angle to the fine tool (tip) 4 using a motor and reciprocating in the X-axis direction. By making it move, a linear fine groove can be created.
Further, the coarse movement of the Z-axis feed mechanism 9 is a motor, and the fine movement is a fine movement apparatus using a piezoelectric element. This precise feed is a particularly important mechanism for reflecting the processing accuracy of the groove width created.
[0014]
First, the distance between the tip of the fine tool 4 and the workpiece 2 is set to 40 μm using a CCD camera, and the upper rotating electrode (= tip of the fine tool 4) and the lower fixed electrode (= XY axis table 1). After the liquid composition 3 is dropped between the two, the orientation of the abrasive grains in the liquid composition 3 is applied as an applied electric field by applying a frequency of 20 Hz and an electric field strength of ± 3.0 kV / mm from the AC high voltage power supply 8. After that, the Z axis feed mechanism 9 of the precision Z axis table 6 narrows the space between the fine tool (tip) 4 and the workpiece 2 by 10 μm.
Next, the fine tool (front end) 4 was rotated at 60,000 rpm for 1 minute by the air spindle 5 for processing. A situation in which abrasive grains are held by the fine tool (tip) 4 by an electric field of 0.5 to 1.5, scattering of abrasive grains due to centrifugal force is suppressed, and only machining waste is ejected out of the electric field, thereby promoting machining. Was observed.
Evaluation after processing was performed with an inverted microscope.
The recess obtained from this processing experiment was able to create a finely processed portion having a bottom diameter of 10 μm and a top surface of approximately 30 μm in diameter.
Also, as shown in FIG. 3, when the θ-axis feed mechanism 7 is driven, the fine tool 4 is angled, the fine tool 4 is rotated, and the XY axis table 1 is reciprocated back and forth. Due to the difference, a relative speed was generated in the abrasive grains, and the situation where the rolling operation worked and the processing progressed was observed.
[0015]
As mentioned above, although the Example of this invention was shown, this invention is not limited to the said Example, Unless it changes the structure as described in a claim, it can implement in any way.
[0016]
【The invention's effect】
As described above, the fine machining method of the present invention can control and hold the arrangement of abrasive grains at the tip of a fine tool by an electric field, and the scattering of abrasive grains due to the centrifugal force generated by the rotation of the tool. Can be suppressed and held by an electric field, and self-dressing and impact force machining can be promoted by the movement of the abrasive grains that occur when the electric field polarity of the abrasive grains is switched.
Further, the microfabrication apparatus of the present invention can realize downsizing of the apparatus, can easily suppress accuracy compensation, and can realize an apparatus with high machining accuracy and low cost. In addition, there is a possibility that the scale in introducing the equipment for realizing the processing environment can be greatly reduced from the current level.
[Brief description of the drawings]
FIG. 1 is a schematic view of a microfabrication apparatus used in Examples.
FIG. 2 is a schematic schematic diagram showing an enlarged view between a fine tool and a workpiece when performing a digging process.
FIG. 3 is a schematic diagram showing an enlarged view of a state between a fine tool and a workpiece when the fine tool is provided with an angle when performing linear groove processing.
[Explanation of symbols]
1 XY axis table 2 Work piece (slide glass)
3 Liquid Composition 4 Fine Tool 5 Air Spindle 6 Precision Z Axis Table 7 θ Axis Feed Mechanism 8 Supply AC High Voltage Power Supply 9 Z Axis Feed Mechanism

Claims (2)

Tip to a fine electrode having a spherical shape, while the other electrode is disposed in the lower portion of the workpiece, which is placed in a non-contact state in close proximity to the tip and workpiece microelectrodes, the main component of the solvent 20 Silicone oil having a viscosity of 1 to 1,000 cSt at ° C, and a liquid composition in which abrasive particles made of insulating particles or semiconductor particles having an electrical dielectric property with a particle size of 0.1 to 30 μm are dispersed in this solvent. It arranged things, electric field strength ± 0.3~5kV / mm, the fine electrode is rotated at a high speed abrasive in a state in which abrasive grains while applying an alternating electric field having a frequency of 0.1~100Hz are oriented tumbling A fine processing method characterized in that processing is performed. The tip is attached to the Z-axis table as a fine electrode having a spherical shape, the other electrode is an XY axis table, and the tip of the fine electrode is arranged in a non-contact manner on the XY axis table. The main component of the solvent has a viscosity of 1 to 1,000 cSt at 20 ° C. between the workpiece placed on the XY axis table and the tip of the fine electrode. A liquid composition in which abrasive particles made of insulating particles or semiconductor particles having an electric dielectric property with a particle diameter of 0.1 to 30 μm are dispersed in this solvent, and the electric field strength between the electrodes is ± A fine processing apparatus capable of performing fine processing by applying and controlling an AC electric field of 0.3 to 5 kV / mm and a frequency of 0.1 to 100 Hz.

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