KR102116179B1 - Apparatus for polishing an object and method of polishing an object - Google Patents

Abstract

A rotary polishing unit having a fixing portion capable of fixing a magnetorheological fluid on the upper portion, and is provided to be movable on an upper portion of the rotary polishing unit to face the rotary polishing unit, and vacuums the object to face the magnetic rheological fluid. Using a vacuum chuck unit for holding, a magnetic rheological fluid supply unit provided to supply the magnetic rheological fluid on the rotary polishing unit and a slurry supply unit provided to supply a polishing slurry between the magnetic rheological fluid and the object do. Therefore, a large-area object can be uniformly polished as a whole.

Description

Object polishing apparatus and object polishing method {APPARATUS FOR POLISHING AN OBJECT AND METHOD OF POLISHING AN OBJECT}

Embodiments of the present invention relate to an object polishing apparatus and an object polishing method. More specifically, the present invention relates to an object polishing apparatus and an object polishing method capable of polishing an edge or a surface of an object using a magnetorheological fluid.

Magnetic rheological fluids are sensitive materials that have a response time of several milliseconds to the applied magnetic field. The magnetorheological fluid consists of a mixture of carbonyl iron and a non-magnetic carrier fluid for dispersion of carbonyl iron powder.

The magnetorheological fluid has been applied to various fields, and is particularly used in fields such as dampers and polishing.

Meanwhile, according to a conventional mechanical polishing apparatus and a polishing method, a chemical mechanical polishing (CMP) process for polishing and planarizing a semiconductor wafer is performed.

In the chemical mechanical polishing process, the polishing pad presses the surface of the object at a relatively high pressure while polishing the object. At this time, scratches, pits may occur on the surface of the object, or damage of the object may occur due to residual stress.

To solve this, in a polishing apparatus using a magnetorheological fluid, a wheel-shaped member rotates at a constant speed, and a magnetorheological fluid is applied thereon to rotate simultaneously. At this time, a slurry is supplied between the subject and the magnetorheological fluid. Therefore, as the slurry contacts the surface of the object, a polishing process is performed as shear force is generated.

However, the conventional polishing method using a magnetorheological fluid may be limited according to the shape of the object, and a lot of processing time is required for uniform polishing of the entire object having a large area. In particular, there is a need for an object polishing apparatus in which a process for polishing and planarization is effectively performed on an object having a large area.

Embodiments of the present invention provides an object polishing apparatus capable of uniformly polishing an entire object having a large area.

Embodiments of the present invention provides an object polishing method capable of uniformly polishing an entire object having a large area.

An object polishing apparatus according to one embodiment of the present invention for achieving the above object, a rotary polishing unit having a fixing portion capable of fixing a magnetic rheological fluid thereon, the rotary polishing unit to face the rotary polishing unit A vacuum chuck unit which is provided to be movable on the upper portion and holds the object using a vacuum force to face the magnetorheological fluid, a magnetorheological fluid supply unit provided to supply the magnetorheological fluid on the rotary polishing unit, and And a slurry supply unit provided to supply a polishing slurry between the magnetorheological fluid and the object.

In one embodiment of the present invention, the fixing portion, the housing portion having fingers extending so as to be spaced apart from each other in the vertical direction from the body, provided between the fingers of the housing portion using at least one permanent magnet on the object A magnetic field generating unit that aligns the magnetic rheological fluid by applying a magnetic field to the magnetic rheological fluid supplied to the magnetic field limiting unit, and a magnetic field limiting unit that limits the magnetic field of the permanent magnet to the inside of the housing using an electromagnet adjacent to the magnetic field generating unit It can contain.

Here, the permanent magnets may be arranged in a horizontal direction.

In addition, the permanent magnets may be arranged to have the same polarity with each other with the fingers interposed therebetween.

Here, each of the permanent magnets has a donut shape and may be arranged in a concentric circle.

Meanwhile, the fixing part may further include a magnetic field passage part serving as a passage of the magnetic field between the permanent magnet and the electromagnet.

In addition, the rotary polishing unit may further include a rotating plate rotatably provided on the upper portion of the housing.

Here, the rotary polishing unit may further include a flattening member to planarize the magnetorheological fluid seated on the top of the rotating plate.

In one embodiment of the present invention, the vacuum chuck unit, a porous chuck for chucking the object, mechanically connected to the porous chuck, a linear driving unit for moving the porous chuck in a linear direction, and mechanically connected to the porous chuck And, it may include a servo motor for rotating the porous chuck.

In one embodiment of the present invention, the slurry supply unit, a slurry storage tank for storing the slurry, a pump for pumping the slurry from the slurry storage tank and supplying the slurry to the object and the slurry recovered from the object in the slurry storage tank It may include a stirring stirrer.

In the object polishing method according to the embodiments of the present invention for achieving the above object, the object is held using a vacuum force. Meanwhile, the magnetorheological fluid is fixed to the upper portion so as to face the object. Thereafter, after the polishing slurry is supplied between the magnetic rheological fluid and the object, the object is polished using the magnetic rheological fluid as a polishing pad. Thereafter, the magnetic field applied to the magnetorheological fluid is released.

In one embodiment of the present invention, before supplying the polishing slurry, the magnetorheological fluid may be planarized.

According to the object polishing apparatus and the polishing method according to the embodiments of the present invention as described above, the polishing pad required in the mechanical and chemical polishing process can be replaced with a magnetic rheological fluid. As a result, residual stress and impact that may occur between the polishing pad and the object used in the mechanical and chemical polishing process can be alleviated. In addition, as the magnetic rheological fluid is circulated and reused, time and cost for replacing the polishing pad can be reduced.

On the other hand, since the permanent magnet is horizontally disposed, the object having a large area can be uniformly polished as a whole, and the polishing effect for a specific area can be improved.

In particular, while applying a magnetic field to a magnetorheological fluid using a permanent magnet, the magnetic field can be released from the magnetorheological fluid using an electromagnet. Therefore, the configuration of the object polishing apparatus is simplified, and power consumption can also be reduced.

1 is a configuration diagram illustrating an object polishing apparatus according to an embodiment of the present invention.
FIG. 2 is a plan view illustrating a driving relationship between the rotary polishing unit of FIG. 1 and an object.
3 is a cross-sectional view for describing the rotary polishing unit of FIG. 1.
4A and 4B are cross-sectional views for describing a magnetic field generated in the rotary polishing unit of FIG. 3.
5 is a flowchart illustrating a method of polishing an object according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention should not be configured as limited to the embodiments described below, but may be embodied in various other forms. The following examples are provided to sufficiently convey the scope of the present invention to those skilled in the art of the present invention rather than to provide the present invention to be completely completed.

In the embodiments of the present invention, when one element is described as being disposed on or connected to another element, the element may be disposed or connected directly on the other element, and other elements are interposed between them. It may be. Alternatively, if it is described that one element is disposed or connected directly on the other element, there cannot be another element between them. Terms such as first, second, third, etc. may be used to describe various items such as various elements, compositions, regions, layers and / or parts, but the items are not limited by these terms. Would not.

The terminology used in the embodiments of the present invention is used for the purpose of describing specific embodiments only, and is not intended to limit the present invention. In addition, unless otherwise limited, all terms including technical and scientific terms have the same meaning that can be understood by those of ordinary skill in the art. These terms, such as those defined in conventional dictionaries, will be construed to have meanings consistent with their meanings in the context of the description of the invention and the related art, ideally or excessively intuition, unless explicitly defined. It will not be interpreted.

Embodiments of the present invention are described with reference to schematic illustrations of ideal embodiments of the present invention. Accordingly, variations from the shapes of the illustrations, for example, variations in manufacturing methods and / or tolerances, are those that can be expected sufficiently. Accordingly, the embodiments of the present invention are not limited to specific shapes of regions described as illustrations, but include variations in shapes, and the elements described in the figures are entirely schematic and their shapes Is not intended to describe the exact shape of the elements nor is it intended to limit the scope of the invention.

1 is a configuration diagram illustrating an object polishing apparatus according to an embodiment of the present invention. FIG. 2 is a plan view for explaining a driving relationship between the rotary polishing unit of FIG. 1 and an object.

1 and 2, in one embodiment of the present invention, the object polishing apparatus includes a rotary polishing unit 110, a vacuum chuck unit 130, a magnetic rheological fluid supply unit 170, and a slurry supply unit 150. .

The object polishing apparatus applies a stress and shear force to the object 10 by using a magnetorheological fluid (magneto rheological fluid) 20 as a polishing pad. Thus, the object polishing apparatus can polish the surface of the object 10.

The magnetic rheological fluid 20 may be controlled to flow characteristics such as viscosity and flow by an applied magnetic field. For example, the magnetorheological fluid 20 may include carbonyl iron powder. As a result, when a magnetic field is applied to the magnetic rheological fluid 20, the magnetic rheological fluid 20 may be changed into a columnar chain structure. At this time, a polishing slurry is supplied between the magnetorheological fluid 20 and the object 10. In addition, the magnetic rheological fluid 20 functions as a soft polishing pad.

Meanwhile, the object 10 may include a plate material having a plate shape such as a glass substrate, a semiconductor substrate, or a printed circuit board.

The rotary polishing unit 110 may fix the magnetorheological fluid 20 to the top. The rotary polishing unit 110 is rotatably provided. As the rotary polishing unit 110 rotates, the object 10 may be polished using the slurry supplied to the upper portion of the rotary polishing unit.

The rotary polishing unit 110 includes a first rotating shaft 113, a first servo motor 117 connected to the first rotating shaft 113, a fixing part 111, and a rotating plate 116.

The first rotation shaft 113 extends in the vertical direction. The first rotation shaft 113 transmits rotational force from the first servo motor 117 to the rotation plate 11.

The first servo motor 117 is connected to the lower end of the first rotation shaft 113. The first servo motor 117 provides rotational force to the rotating plate 116 via the first rotating shaft 113. Thereby, the magnetorheological fluid 20 located on the rotating plate 116 may rotate.

The fixing part 111 is located on the rotating plate 111. The fixing part 111 may control the flow characteristics of the magnetic rheological fluid 20 using magnetic force. The fixing part 111 positions the magnetorheological fluid 20 on its upper surface.

The rotating plate 116 is connected to an upper end portion of the first rotating shaft 113. In addition, the rotating plate 116 supports the fixing part 111. As the rotating plate 116 rotates, the magnetorheological fluid 20 located on the rotating plate 116 may rotate together.

The rotating plate 116 may be made of a material having excellent corrosion resistance. For example, the rotating plate 116 may be made of a metal or ceramic material. Thus, when the rotating plate 116 is exposed to water or abrasive, corrosion can be suppressed. In addition, magnetization by magnetic force generated adjacent to the rotating plate 116 may be suppressed. Thereby, it is possible to suppress the rotating plate 116 from distorting the magnetic force.

In one embodiment of the present invention, the fixing part 111, the housing portion 121 having a housing body extending in a horizontal direction and fingers spaced apart from each other and extending upward from the upper surface of the housing body, a magnetic field generator (123a, 123b) and a magnetic field limiting unit 128. (See FIG. 3)

The housing part 121 entirely surrounds the magnetic field generating parts 123a and 123b and the magnetic field limiting part 128 and provides space therein.

The magnetic field generating parts 123a and 123b are located in the housing part 121. More specifically, the magnetic field generators 123a and 123b are disposed between the fingers and are connected to the side walls of each of the fingers. The magnetic field generating units 123a and 123b include at least one permanent magnet 123a and 123b. At this time, the magnetic field generator and the permanent magnet use the same reference number. Therefore, the permanent magnets 123a and 123b can independently provide a magnetic field without a separate power supply to the magnetic rheological fluid 20. That is, the magnetic field generating unit includes permanent magnets 123a and 123b, so that unlike the magnetic force generating unit using a conventional electromagnet, a core, a coil surrounding the core, and a power unit supplying power to the coil may be omitted. Thereby, the configuration of the magnetic force generating portion can be simplified. As a result, the magnetic field generating unit includes permanent magnets 123a and 123b that can replace electromagnets, and thus can have improved power efficiency as well as a relatively simple structure.

The magnetic field limiting part 128 is located in the housing part 121. In addition, the magnetic field limiting unit 128 is located adjacent to the magnetic field generating units 123a and 123b. The magnetic field limiting part 128 includes an electromagnet. The magnetic field limiting unit 128 may include a core, a coil provided to surround the core, and a power applying unit that applies power to the coil. The magnetic field limiting portion may limit the magnetic field generated from the permanent magnets 123a and 123b into the housing portion 121.

Detailed descriptions of the permanent magnets 123a and 123b and the magnetic field limiting unit 128 will be described later.

The vacuum chuck unit 130 holds the object 10 using a vacuum force. That is, the object 10 may be fixed below the vacuum chuck unit 110.

The vacuum chuck unit 130 includes a second rotating shaft 133, a second servo motor 137 connected to the second rotating shaft to rotate the second rotating shaft, and a porous chuck 131.

The porous chuck 131 is connected to the lower end of the second rotary shaft 133. Accordingly, the porous chuck 131 may rotate together according to the rotation of the second rotation shaft 133 using the rotational force provided from the second servo motor 137. As a result, the object 10 held by the porous chuck 131 may rotate together.

The porous chuck 131 may be made of a porous ceramic material or a separately processed metal material.

The porous chuck 131 is connected to a vacuum generator (not shown). Thus, the porous chuck can hold the object 10 using a vacuum force. For example, the vacuum generator may include a vacuum pump (not shown).

The vacuum chuck unit 130 is provided to be movable. For example, the vacuum chuck unit 130 may move in a horizontal direction, that is, in the X direction or the Y direction. To this end, a horizontal driving unit 135 is separately provided to move the vacuum chuck unit 130. Therefore, the vacuum chuck unit 130 may move relatively horizontally with respect to the rotary polishing unit 110. The horizontal driving unit 135 may include an LM guide, a ball screw, and the like.

Meanwhile, the vacuum chuck unit 130 is connected to the vertical driving unit 136. Therefore, as the vertical drive unit 136 moves the vacuum chuck unit 130 up and down, the vacuum chuck unit 130 approaches the rotary polishing unit 110 or moves away from the rotary polishing unit 110. Can lose. The vertical driving unit 136 may include an LM guide, a ball screw, and the like.

3, 4A and 4B are cross-sectional views for describing a magnetic field generated in the rotary polishing unit of FIG. 1.

3 and 4A, when the magnetic field limiting part includes a coil and no current flows through the coil, the magnetic field limiting part 128 does not affect the magnetic field generating parts 123a and 123b. Therefore, a magnetic field is generated independently around the permanent magnets 123a and 123b included in the magnetic field generating units 123a and 123b. At this time, the magnetic field is applied to the magnetic rheological fluid 20, the magnetic rheological fluid 20 is changed from a Newtonian fluid state to a strong semi-solid (semi-solid) state. As a result, the viscous and yield stress of the magnetorheological fluid may increase several times to several tens of times.

3 and 4B, when the magnetic field limiting unit 128 includes a coil and current flows through the coil, the magnetic field limiting unit 128 applies the magnetic fields of the permanent magnets 123a and 123b to the housing unit. Limited to internal. That is, when the permanent magnets 123a and 123b need to release the magnetic field applied to the magnetorheological fluid, a current flows through the coil included in the magnetic field limiting unit 128. At this time, by generating interference between the permanent magnets 123a and 123b and the coil, the magnetic field forms a magnetic field loop in the housing part 121 so that the magnetic field is limited to the inside of the housing part 121. On the other hand, the magnetic field applied to the magnetorheological fluid 20 is released (see FIG. 4B).

In one embodiment of the present invention, the fixing part 111 may further include a magnetic field passage part 122.

Referring to FIG. 3 again, the magnetic field passage part 122 is connected to the housing part 121. The magnetic field limiting part 128 is provided to surround the magnetic field passage part 122. The magnetic field passage part 122 may function as a passage of a magnetic field that magnetically connects the housing part 121, the permanent magnets 123a and 123b, and the magnetic field limiting part 128.

At this time, the polarities of the permanent magnets 123a and 123b arranged between the fingers may be provided to have the same polarity with respect to the fingers. Accordingly, a magnetic field surrounding the permanent magnets 123a and 123b is formed along the extending direction of the permanent magnets 123a and 123b. As a result, the magnetic field is applied to the magnetic rheological fluid, so that the flow characteristics of the magnetic rheological fluid can be adjusted.

Each of the permanent magnets 123a and 123b has a donut shape and may be arranged to have a concentric circle.

Referring back to FIG. 1, the slurry supply unit 150 supplies a polishing slurry between the magnetic rheological fluid and the object 10. In addition, the slurry supply unit 150 may reuse the recovered slurry by recovering the slurry discharged after polishing on the object 10.

In one embodiment of the present invention, the slurry supply unit 150 may include a slurry reservoir 151, a first pump 153, and a stirrer 154.

The slurry storage tank 151 corresponds to a container for storing the slurry. By controlling the temperature of the slurry storage tank 151, the slurry maintained at a constant temperature may be supplied on the magnetorheological fluid.

The first pump 153 pumps the slurry from the slurry reservoir 151 and supplies it to the magnetorheological fluid 20.

The stirrer 154 stirs the slurry recovered from the magnetorheological fluid 20 in the slurry reservoir 151. Thus, precipitation of the abrasive particles in the slurry in the slurry reservoir 151 can be suppressed.

The magnetorheological fluid supply unit 170 supplies the magnetorheological fluid 20 on the rotating plate 116. The magnetic field generated by the permanent magnets 123a and 123b may be applied to the magnetorheological fluid 20 supplied on the rotating plate 116. Thereby, the flow characteristics of the magnetorheological fluid 20 can be controlled. Therefore, the magnetorheological fluid 20 can function as a polishing pad.

In one embodiment of the present invention, the rotary polishing unit 110 may further include a planarization member 119 (see FIG. 2).

The flattening member 119 is positioned on the rotating plate 116. The planarization member 119 planarizes the magnetorheological fluid 20 located above the rotating plate 116. As the magnetorheological fluid 20 has a flattened upper surface, polishing can be uniformly performed over the entire area of the object 10. The flattening member 119 may be, for example, a shaper. That is, the shaper may have a bar shape extending in a horizontal direction. As a result, as the rotating plate 116 rotates under the shaper, the magnetorheological fluid 20 provided on the rotating plate 116 may have a flat upper surface.

5 is a flowchart illustrating a method of polishing an object according to an embodiment of the present invention.

Referring to FIG. 5, in the method of polishing an object according to an embodiment of the present invention, the object is held using a vacuum force. (S110) A vacuum chuck unit 130 (see FIG. 1) to hold the object. This can be used. In addition, the lower surface of the object may be polished.

On the other hand, the magnetic rheological fluid 20 is fixed on the upper side so as to face the object 10. (S120) A rotary polishing unit 110 (see FIG. 1) is used to fix the magnetic rheological fluid 20. You can.

Thereafter, a polishing slurry is supplied between the magnetorheological fluid 20 and the object 10 (S140).

The object 10 is polished using the magnetic rheological fluid 20 as a polishing pad (S150). During the polishing process for polishing the object 10, the flow characteristics of the magnetorheological fluid may be controlled by a magnetic field generated by a permanent magnet.

Subsequently, when the polishing process ends, the magnetic rheological fluid is released from the permanent magnet while limiting the magnetic field of the permanent magnet.

In one embodiment of the present invention, before supplying the polishing slurry, a process of flattening the magnetorheological fluid may be additionally performed. A planarization member 119 (see FIG. 2) may be used to planarize the magnetorheological fluid.

Although described above with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that there is.

110: rotary polishing unit 111: rotating plate
113: first rotation axis 116: fixing portion
130: vacuum chuck unit 131: vacuum chuck
133: second rotation shaft 135: horizontal drive unit
136: vertical drive unit 137: second servo motor
150: slurry supply unit 170: magnetic rheological fluid supply unit

Claims (12)

A rotary polishing unit having a fixing portion capable of fixing the magnetorheological fluid to the upper portion;
A vacuum chuck unit movably provided on an upper portion of the rotary polishing unit to face the rotary polishing unit, and holding an object using a vacuum force to face the magnetic rheological fluid;
A magnetorheological fluid supply unit provided to supply the magnetorheological fluid on the rotary polishing unit; And
And a slurry supply unit provided to supply a polishing slurry between the magnetorheological fluid and the object, wherein the fixing unit comprises:
A housing part having fingers extended to be spaced apart from each other in the vertical direction;
A magnetic field generator provided within the fingers of the housing part and applying a magnetic field to the magnetorheological fluid supplied to the object using at least one permanent magnet to align the magnetorheological fluid; And
And a magnetic field limiting part which is adjacent to the magnetic field generating part and restricts the magnetic field of the permanent magnet to the inside of the housing part by using an electromagnet. delete The object polishing apparatus according to claim 1, wherein the permanent magnets are arranged in a horizontal direction. The apparatus of claim 1, wherein the permanent magnets are arranged to have the same polarity with each other with the fingers interposed therebetween. The object polishing apparatus according to claim 4, wherein each of the permanent magnets has a donut shape and is arranged concentrically. The object polishing apparatus according to claim 1, wherein the fixing part further comprises a magnetic field passage part serving as a passage of the magnetic field between the permanent magnet and the electromagnet. According to claim 1, The rotary polishing unit,
The object polishing apparatus further comprises a rotating plate rotatably provided on the upper portion of the housing. The object polishing apparatus according to claim 7, wherein the rotary polishing unit further comprises a flattening member to planarize the magnetorheological fluid seated on the top of the rotating plate. According to claim 1, The vacuum chuck unit
A porous chuck chucking the object;
A linear drive unit mechanically connected to the porous chuck and moving the porous chuck in a linear direction; And
And a servo motor mechanically connected to the porous chuck and rotating the porous chuck. According to claim 1, The slurry supply unit,
A slurry storage tank for storing the slurry;
A pump that pumps the slurry from the slurry reservoir and supplies it to the object; And
And a stirrer for stirring the slurry recovered from the object in the slurry reservoir. delete delete

Images