KR101318970B1 - Apparatus and method for fine processing - Google Patents

Abstract

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an apparatus and method for fine surface processing of a hard brittle material having excellent process speed, cost and processing surface quality. ; A first processing device for forming a pattern on the surface of the material to be processed; And a second temporary factory for polishing the surface of the material to be processed, wherein the first temporary factory is a powder blasting apparatus for ejecting abrasive particles at pneumatic pressure to cut the surface of the material. It is characterized in that the water jet processing apparatus for jetting the water mixed with the particles to polish the surface of the material.
According to the present invention, by providing the powder blasting apparatus and the water jet apparatus in one processing equipment, the surface pattern processing can be performed quickly and inexpensively, and the high surface quality can be obtained.
In addition, by having a transport means for moving the nozzle for the powder blasting nozzle and the water jet, there is an effect that the manufacturing cost of the equipment is greatly reduced.

Description

Micromachining apparatus and method {APPARATUS AND METHOD FOR FINE PROCESSING}

The present invention relates to an apparatus and method for micromachining the surface of a hard brittle material, and more particularly, to an apparatus and method for fine surface machining of a brittle material having excellent process speed, cost, and processing surface quality.

In general, in the case of glass materials, the optical and aesthetic effects are large, and the chemical stability is high, so the use environment is wide. In addition, due to its high mechanical hardness, good thermal stability, high electrical insulation, and no harm to humans or the environment, its uses are very diverse and historically, its value is expected to continue in the future.

Due to these functional advantages, glass has a universal utility value, and in particular, in the optical device field, glass has a unique utility value, and not only optical systems, but also display industry such as LCD and LED, solar power generation and secondary battery, etc. It is also widely used in the renewable energy industry. In addition, because of glass's unique characteristics, it is also used in analytical diagnostic devices such as DNA analysis, enzyme reaction, immunoassay, and cell biology, that is, various kinds of biochips. These applications have recently become the basis for the fabrication of micro electromechanical systems (MEMS).

On the other hand, hard and brittle brittle material other than glass, such as alumina (alumina, Al ₂ O ₃ ), zirconia (zirconia, ZrO ₂ ), silicon (silicon), quartz (quartz), amorphous plastic (PMMA, COP, COC) , PC) and the like, and because they have properties similar to those of glass, they are widely used as various parts for various MEMS applications or microfabrication technology applications.

The technique of realizing a shape or generating a surface structure at a fine scale on the glass and other brittle brittle materials having such high utility is as follows, and ceramics is more limited than the following methods.

First, there are wet etching and dry etching by etching methods.

Wet etching is a technique used in traditional silicon processes (semiconductor or MEMS processes) to remove material by hydrofluoric acid based chemical etching followed by sacrificial layer generation through photolithography. The material removal rate is low, there are many quality deterrents such as the lifting of the sacrificial layer, the isotropy of material removal, etc., and it is very harmful to the human body and the environment by the use of hydrofluoric acid, and there is a disadvantage of using a certain level of expensive equipment.

Dry etching also requires a process of forming a sacrificial layer similar to wet etching, so it can also be seen as part of the semiconductor process. It is a material removal method based on argon source plasma, and also has low material removal rate, environmental problems such as greenhouse gas emission, and high process cost such as vacuum device.

Next, there is a laser processing method, which is widely used as a glass micromachining method, and is suitable for micromachining to achieve a degree of processing of about 1 micron. Laser processing can be applied not only to the removal of glass materials such as cutting, but also to changes in local physical properties such as refractive index changes. As the lasers used, UV lasers, pulsed lasers, CO ₂ lasers, femtosecond lasers, and various sources are very diverse, and the processing efficiency of various glass structures is high. However, laser processing equipment is expensive and low in energy efficiency, and it is difficult to apply it as a general microprocessing technology because it is difficult to process without having a professional processing technology.

Finally, the mechanical processing methods are typical of cutting, grinding (or polishing) and powder blasting.

The cutting method is a method using a fine milling tool, and can be processed without brittle fracture of glass through ultra fine cutting. There is a big advantage that there is no restriction of the shape to implement, but in order to maintain high quality, a lot of equipment and technical know-how is required.

Grinding method is a method using a grinding wheel embedded with abrasive particles, there is an advantage that can be processed to a high quality material. Polishing is a technique that falls outside the scope of micromachining and is a very smooth and flat surface. Grinding and polishing require very suitable microtool for microstructure, making machining very difficult.

Powder blasting is a method that can be easily applied at a low cost in the micro glass processing technology and is called a mechanical etching method. 10 to 100㎛ diameter fine abrasive particles are projected on the glass surface at high speed, so that the glass is brittle and broken by the fine particles, and the material is removed. Powder blasting is typically used for the manufacture of PDP display bulkheads and micro-pores, and the material removal rate is very high, while the surface roughness is very rough and poor in terms of material removal principle due to cracks and brittle fracture.

As described above, the glass micromachining technology is diverse, but there is no technology that satisfies all aspects of processing efficiency, low cost, and high quality.

Korean Patent Publication No. 10-1995-0702511 has been filed as a technology aimed at processing efficiency and high quality. This application relates to a technique for improving the quality of the surface by irradiating the laser in the ultraviolet wavelength region to the machining surface after the rapid grinding using a mechanical grinding or laser in the infrared wavelength region to the ceramic sintered body. However, surface processing with lasers is problematic because of the high cost of the equipment.

Republic of Korea Patent Publication No. 10-1995-0702511

The present invention is to solve the problems of the prior art described above is to provide a micro-processing apparatus and method of a hard brittle material that can be applied to the processing of micro equipment, such as MEMS or biochips at low cost to ensure the efficiency of processing and high quality The purpose is to provide.

Micro-machining apparatus according to the present invention for achieving the above object, the equipment for processing the surface of the hard brittle material, such as glass and ceramic, the workbench is located; A first processing device for forming a pattern on the surface of the material to be processed; And a second temporary factory for polishing the surface of the material to be processed, wherein the first temporary factory is a powder blasting apparatus for ejecting abrasive particles at pneumatic pressure to cut the surface of the material. It is characterized in that the water jet processing apparatus for jetting the water mixed with the particles to polish the surface of the material.

The inventors of the present invention have noted a powder blasting method which is the cheapest and broadest application range as a method of processing the surface of a brittle material. The powder blasting method has a problem in that the processed surface is very rough and difficult to apply to a fine product such as MEMS because glass is brittle and broken by fine abrasive particles.

The inventors of the present invention provide a surface cutting and water jet by fast and inexpensive powder blasting through a fine processing device further comprising a first processing device by powder blasting and a water jet device for surface polishing by a second processing plant. By performing the surface polishing by one equipment, a fine processing apparatus of a hard brittle material has been developed that can greatly improve the quality of the processed surface without adding cost.

At this time, the first processing apparatus is a wet blasting apparatus that atomizes and sprays an abrasive slurry mixed with water and abrasive particles, and a first storage for storing the abrasive nozzle and the first nozzle for ejecting the abrasive slurry at pneumatic pressure. It includes a regulator for adjusting the air pressure discharged through the tank and the first nozzle, it is preferred that the first nozzle sprays the abrasive slurry by spraying.

The use of wet powder blasting reduces the contamination of the air by the abrasive particles because the abrasive particles are not dispersed in the atmosphere.

In addition, the water jet processing apparatus includes a second nozzle for ejecting the abrasive slurry in which the abrasive particles are dispersed, a second storage tank for storing the abrasive slurry, and a liquid pump for regulating the pressure of the abrasive slurry ejected from the second nozzle. desirable.

And the micromachining apparatus further includes a conveying means for conveying the first nozzle and the second nozzle and / or a conveying means for conveying the worktable, the X-axis, Y-axis, Z-axis relative to the first, second nozzle and the worktable It is desirable to implement directional motion and rotational motion.

Since the microfabrication apparatus of the present invention does not provide a transfer means to each of the first nozzle and the second nozzle, the manufacturing cost of the equipment can be reduced.

Furthermore, the fine processing apparatus further includes a recovery means for recovering the abrasive particles, and the recovery means includes a classification means for classifying the abrasive particles by size, so that the abrasive particles can be recycled. Since both the first processing device and the second processing device use the polishing slurry, recovery means in the form of a water tank can be provided to recover the abrasive particles.

According to another aspect of the present invention, there is provided a method for processing a surface, the method for processing a surface of a hard brittle material using the above-described fine processing device, comprising: preparing a material to be processed; Forming a mask having an opening formed on a surface of the target material; A powder blasting step of ejecting the abrasive particles by air pressure with respect to the target material on which the mask is formed to form a pattern; A water jet step of jetting water mixed with abrasive particles to the target material on which the mask is formed to polish the surface of the material; And removing the mask, wherein the powder blasting step and the water jet step are performed in the same processing equipment.

By inexpensive and fast powder blasting and water jet polishing to enhance the quality of the machined surface in one machine, the surface of the hard brittle material can be processed at low cost with excellent processing speed and quality.

At this time, the powder blasting step is a wet powder blasting sprayed by atomizing the abrasive slurry mixed with water and abrasive particles, the abrasive particles have an average diameter of 11㎛ or more, the abrasive slurry used is 5 ~ It is preferable to mix with water in the ratio range of 10wt%. In addition, it is preferable that the discharge pressure of the wet powder blasting is in the range of 1 to 4 bar, and the impact velocity of the particles is in the range of 80 to 200 m / s.

The powder blasting step of the present invention determines the processing conditions focusing on the processing speed rather than the quality of the processing surface.

The abrasive particles used in the water jet have an average diameter of 11 μm or less, and the discharge pressure of the water jet is preferably in the range of 3 to 20 bar.

The water jet step of the present invention determines processing conditions with an emphasis on improving the quality of the processing surface.

Moreover, it is preferable that the mask formed in this invention is a metal plate. It is desirable to use a metal plate as a mask to withstand both the powder blasting step and the water jet step.

According to the present invention configured as described above, by providing the powder blasting apparatus and the water jet apparatus in one processing equipment, the surface pattern processing can be performed quickly and inexpensively, and the high surface quality can be obtained.

In addition, since the surface quality of the processed surface is high, there is an effect that can greatly improve the performance of the biochip to control the flow characteristics of the microfluid.

Furthermore, by providing a transport means for moving the nozzle for the powder blasting and the nozzle for the water jet, there is an effect that the manufacturing cost of the equipment is greatly reduced.

1 is a schematic diagram showing a processing method using a micromachining apparatus according to an embodiment of the present invention.
2 is a process table showing a machining step using a micromachining apparatus according to an embodiment of the present invention.
3 is a schematic diagram showing a machining step using a micromachining apparatus according to an embodiment of the present invention.
4 is a view showing the principle of wet powder blasting according to the atomization.
It is a figure which shows the principle of the grinding | polishing process by a water jet.
6 is a micrograph showing a processing result using a micromachining apparatus according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, embodiments of the present invention will be described in detail.

1 is a schematic diagram showing a processing method using a micromachining apparatus according to an embodiment of the present invention.

The micromachining apparatus of this embodiment includes a first processing apparatus 10 composed of a wet powder blasting apparatus, a second processing apparatus 20 composed of a water jet apparatus, and a work bench 30 for positioning the material 100 to be processed. Include.

The first processing apparatus 10 includes a first nozzle 12 for ejecting a polishing slurry containing abrasive particles into water through compressed air, a first storage tank 14 for storing the polishing slurry, and a first nozzle 12. It includes a regulator 16 for adjusting the air pressure injected into.

The second processing apparatus 20 is injected into the second nozzle 22 for ejecting the abrasive slurry mixed with abrasive particles, the second storage tank 24 and the second nozzle 22 for storing the abrasive slurry for water jet processing. It includes a fluid pump 26 for regulating the pressure of the fluid to be.

The work bench 30 is a place where the processing target material 100 on which the mask 200 is formed is located, and a water tank for collecting the abrasive slurry ejected as a result of the operation of the first processing apparatus 10 and the second processing apparatus 20. It is located inside the abrasive slurry recovery means (not shown) of the type. Since the processing equipment of this embodiment uses wet powder blasting and water jet processing, both polishing slurries are used during the processing, and the polishing slurries can be recovered and reused. In particular, the recovery means is provided with a classification means for classifying the abrasive particles by size, it is possible to immediately recycle the abrasive particles, it is possible to reduce the process cost by recycling the abrasive particles.

And although not shown, the microfabrication apparatus of this embodiment is provided with the conveying means for conveying the 1st, 2nd nozzle 22 or the worktable 30. As shown in FIG.

The conveying means allows the first and second nozzles 12 and 22 and the work table 30 to move relative to each other or to rotate in the X, Y, and Z directions. The conveying means may be any one that implements relative movement between the first and second nozzles 12 and 22 and the work table 30, and the configuration is not particularly limited. For example, only the transfer means for moving the first and second nozzles 12 and 22 in the X-axis, Y-axis, Z-axis direction and rotational movement may be provided, and the work table 30 may be X-axis, Y-axis, or Z-axis. It may be provided with only the conveying means for moving in the direction and rotation, it may be provided with both the conveying means for moving the first, second nozzles (12, 22) and the conveying means for moving the work table (30).

Since the micromachining apparatus of the present embodiment does not provide a conveying means to each of the first nozzle and the second nozzle even when the microprocessing apparatus includes the conveying means for moving the first and second nozzles 12 and 22, the manufacturing cost of the equipment is reduced. Can be saved.

2 and 3 is a process table and schematic diagram showing a machining step using a micromachining apparatus according to an embodiment of the present invention.

First, the processing target material 100 is prepared as shown in FIG. 3 (a). The material to be processed is not particularly limited as a hard brittle material, and may include glass, ceramic, or amorphous plastic.

Next, as shown in FIG. 3B, a mask 200 having an opening 220 for processing is formed on the surface of the material 100 to be processed. The opening portion 220 is a portion patterned according to a shape to be formed on the surface of the material to be processed, and the surface of the material to be processed is processed according to the shape of the opening 220.

A common method of forming such a mask is a method using photolithography. Photolithography forms masks by patterning the photoresist and using itself as a mask, or by filling a mask material in an unpatterned space. Such a photolithography mask has a photosensitive dry film itself, an elastomer, or a metal deposition layer. However, the dry film and the elastomer may be applied to powder blasting among the mask materials. However, since the mask may be separated from the surface during the water jet processing, the metal deposition layer may be formed of a material.

Another method of forming the mask is by using a metal plate. This is to form a fine through pattern on a metal plate made of stainless steel or invar by etching or the like, and attach the metal plate to the surface of the material to be processed. Since the metal plate mask can withstand water jet processing well, it is suitable as a mask for surface treatment of this embodiment.

The material to be processed in which the patterned mask is formed is placed on a work table of the microfabrication apparatus according to the present embodiment. The worktable can fix the material to be processed and has a recovery means capable of recovering the abrasive particles used in the processing.

And as shown in Fig. 3 (c), powder blasting is performed by the primary processing for the material to be processed located on the workbench. Powder blasting includes dry powder blasting for directly injecting abrasive particles through air pressure and wet powder blasting for atomizing (atomizing) and discharging the polishing slurry in which the abrasive particles are dispersed in water. In the case of dry powder blasting, since the abrasive particles are easily dispersed in the air and contaminate the environment as compared to the wet powder blasting using the abrasive slurry, wet powder blasting is used in this embodiment.

4 is a view showing the principle of wet powder blasting according to the atomization. When the abrasive slurry mixed with abrasive particles and water is jetted into the compressed air, the fluid discharged from the nozzle is atomized without maintaining the continuous phase of the liquid by the disturbance of air.

As shown in Figure 3 (c), during the atomization process by the viscosity of the liquid and the surface tension is aggregated around the abrasive grains to form a fine droplet 300, the fine droplet 300 is the mask 200 The abrasive particles therein erode the surface while colliding with the surface of the material to be processed 100 that is not formed.

In the powder blasting step, the abrasive particles use Al ₂ O ₃ or SiC, and the particles having an average diameter of about 11 μm or more and no more than 1000 particles are used. As the size of the abrasive grains used for powder blasting increases, the processing speed increases while the quality of the processing surface decreases. Since the processing method of the present embodiment includes a polishing process to secondly improve the surface quality, it is preferable to increase the processing speed by using particles having a size of 1000 or less.

Polishing slurry for wet powder blasting is to disperse the abrasive particles in water at a rate of 5 ~ 10wt%. In the wet powder blasting process, a pressure of 1 to 4 bar is used for the discharge pressure of the compressed air, but a difference in the pressure range may occur depending on the diameter of the discharge port and the shape of the nozzle, and 80 to 200 m / Adjust in the range of s.

This wet powder blasting step proceeds until the processing site reaches a predetermined processing depth.

As shown in Fig. 3 (d), the material to be subjected to wet powder blasting is polished by water jet in a secondary process. This water jet polishing smoothly polishes the surface without brittle fracture of the material by a flow that spreads after the fluid 400 including the abrasive particles collides with the surface of the hard brittle material.

It is a figure which shows the principle of the grinding | polishing process by a water jet. When the water jet containing abrasive particles collides with the surface of the material to be processed at 90 degrees, it exhibits an symmetric, W-shaped smooth cross-sectional profile as shown in Fig. 5 (a). This results in high pressure in the center of the water jet as shown in FIG. 5 (b), but stagnation of the fluid velocity as shown in FIG. 5 (c), which causes the center to impact particles. This is because the energy cannot cause cracks or the like inside the material. On the other hand, as shown in Fig. 5 (b), the fluid accelerates at the surface of the material in the radially spreading flow (axis symmetry), whereby the abrasive particles in the fluid form the surface of the workpiece. Fine grinding. This polishing, after all, is not caused by the pressure at the center of the water jet, but by the relative friction with the surface as the fluid flows along the surface, and not by brittle fracture by cracks, but by the removal of the material in ductile mode.

Therefore, when using a low pressure water jet in the discharge pressure range of 3 ~ 20bar, the material removal rate is lower than that of the blasting process, but it can be seen that a surface having a very good surface roughness can be formed by removing the material in the ductile mode. Furthermore, it can be seen that when water jet processing is performed on the material on which the mask is formed, the surface of the processed portion can be processed because the material removal in the ductile mode occurs along the powder blasted processing surface in the opening of the mask. have.

In the water jet step, the abrasive grains are Al ₂ O ₃ or CeO ₂ , and the like, and particles having an average diameter of about 11 μm or less are used for at least 1000 particles. In the water jet step, it is preferable to use particles having a small size, because of the purpose of mirroring the processed surface.

Finally, as shown in Fig. 3 (d), when the mask is removed, a hard brittle material having a fine pattern having a high quality processing surface can be obtained.

6 is a micrograph showing a processing result using a micromachining apparatus according to an embodiment of the present invention.

Figure 6 (a) shows the result of processing the surface by wet powder blasting using 600 times, that is, Al ₂ O ₃ abrasive particles having a particle diameter of about 20㎛. In the figure on the left, the part where the opening of the mask is formed is processed, and the groove is formed. In the picture on the right, the processing surface is very rough due to brittle fracture. The measured surface roughness reached 0.27 micrometer in average value (Rms), and reached the maximum value (Rmax) in 1.6 micrometer.

6 (b) to 6 (d) show the results of surface treatment by water jet using 2500 times, that is, Al ₂ O ₃ abrasive particles having a particle diameter of about 5.5 μm.

Fig. 6 (b) shows a case where the injection nozzle reciprocates twice at a speed of 1 mm / s along the line width. Although the processed surface was polished by the water jet, it can be seen that cracks remain on the surface. The measured surface roughness showed an average value Rms of 49 nm and a maximum value Rmax of 0.36 μm.

FIG. 6 (c) shows a case where the injection nozzle reciprocates four times at a speed of 1 mm / s along the line width. It can be seen that the cracks on the surface are all removed to obtain a flat surface. The measured surface roughness showed an average value Rms of 18 nm and a maximum value Rmax of 0.27 μm.

Fig. 6 (d) shows a case where the injection nozzle reciprocates six times at a speed of 1 mm / s along the line width. It was confirmed that the surface was smoother. The measured surface roughness was 14 nm in average value (Rms) and the maximum value (Rmax) was 0.05 μm, which further improved the surface quality.

While the present invention has been described through the preferred embodiments, the above-described embodiments are merely illustrative of the technical idea of the present invention, and various changes may be made without departing from the technical idea of the present invention. Those of ordinary skill will understand. Therefore, the scope of protection of the present invention should be construed not only in the specific embodiments but also in the scope of claims, and all technical ideas within the scope of the same shall be construed as being included in the scope of the present invention.

10: first processing device 12: first nozzle
14: first storage tank 16: regulator
20: second processing apparatus 22: second nozzle
24: second storage tank 26: liquid pump
30: worktable 100: material to be processed
200: mask 220: opening

Claims (16)

Equipment for processing surfaces of hard brittle materials such as glass and ceramics,
A work bench on which the material to be processed is located;
A first processing device for forming a pattern on the surface of the material to be processed; And
A second temporary factory for polishing the surface of the material to be processed;
The first temporary plant is a wet blasting apparatus that atomizes and sprays a polishing slurry in which water and abrasive particles are mixed, and the second temporary plant sprays water mixed with abrasive particles to polish the surface of the material. Fine processing device, characterized in that the water jet processing device.
delete The method according to claim 1,
The wet blasting apparatus,
A first nozzle for ejecting the polishing slurry at pneumatic pressure;
A first storage tank for storing the polishing slurry; And
It includes a regulator for adjusting the air pressure discharged through the first nozzle,
And the first nozzle sprays the polishing slurry to eject the fine slurry.
The method according to claim 1,
The water jet processing apparatus,
A second nozzle for ejecting the polishing slurry in which the abrasive particles are dispersed;
A second storage tank for storing the polishing slurry; And
And a liquid pump for adjusting the pressure of the polishing slurry ejected from the second nozzle.
The method according to claim 1,
The micro-machining apparatus further comprises at least one conveying means of the conveying means for conveying the nozzle of the wet blasting apparatus, the nozzle of the water jet processing apparatus and the conveying means for conveying the work table. .
The method according to claim 5,
The conveying means is a micro-machining device, characterized in that for implementing the X-axis, Y-axis, Z-axis movement and rotational movement between the first, the second nozzle and the work table.
The method according to claim 1,
The fine processing apparatus further comprises a recovery means for recovering the abrasive particles.
The method of claim 7,
The fine processing device, characterized in that the recovery means comprises a classification means for classifying the abrasive particles by size.
As a method of processing the surface of a hard brittle material using the microfabrication apparatus of any one of Claims 1, 3-8.
Preparing a material to be processed;
Forming a mask having an opening formed on a surface of the target material;
A powder blasting step of ejecting the abrasive particles by air pressure with respect to the target material on which the mask is formed to form a pattern;
A water jet step of jetting water mixed with abrasive particles to the target material on which the mask is formed to polish the surface of the material; And
Removing the mask;
And the powder blasting step and the water jet step are performed in the same processing equipment.
The method according to claim 9,
Wherein said powder blasting step is wet powder blasting which atomizes and jets an abrasive slurry mixed with water and abrasive particles.
The method of claim 10,
Surface treatment method characterized in that the abrasive particles used in the wet powder blasting has an average diameter of 11㎛ or more.
The method of claim 11,
The polishing slurry used in the wet powder blasting is a surface processing method characterized in that the abrasive particles are mixed with water in the ratio range of 5 ~ 10wt%.
The method of claim 12,
Discharge pressure of the wet powder blasting is in the range of 1 ~ 4bar, the impact speed of the particle range of 80 ~ 200m / s.
The method according to claim 9,
Abrasive particles used in the water jet surface processing method, characterized in that the average diameter is 11㎛ or less.
The method of claim 10,
Surface discharge method characterized in that the discharge pressure of the water jet is in the range of 3 ~ 20bar.
The method according to claim 9,
And said mask is a metal plate.

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