JP5380351B2 - Polishing equipment - Google Patents

Description

  The present invention relates to a grinding apparatus used for sucking and holding one surface of a wafer or the like in a manufacturing process of, for example, a semiconductor silicon wafer, and performing mirror polishing (polishing) processing or grinding on the surface opposite to the suction side surface. The present invention relates to a polishing apparatus including:

Conventionally, as this type of polishing device adsorption structure, in the semiconductor device manufacturing process, a disk-shaped porous body is bonded to a support portion made of a vessel-like dense body with an adhesive, and formed on this support portion. There is a vacuum suction device that sucks and holds a substrate such as a semiconductor wafer on the surface of a porous body by vacuum suction from the suction holes thus formed (see, for example, FIG. 1 of Patent Document 1).
Also, a disk-shaped ceramic porous body, a concave suction portion provided so as to surround the entire porous body excluding the adsorption holding portion, and a vessel-like support that supports the porous body and the concave suction portion A vacuum suction device in which the porous body and the support part are directly joined to the concave suction part substantially without any gap, and the average pore diameter of the concave suction part is larger than the average pore diameter of the porous body. (For example, refer to FIG. 2 of Patent Document 1).

JP 2009-224402 A

However, in such a conventional polishing apparatus adsorption structure, foreign matters such as grinding dust (dust) and dust are sucked into the porous body, causing clogging, and a plate-like workpiece such as a wafer is clogged. It is necessary to remove the clogged foreign matter because there is a possibility that the adsorption becomes non-uniform and the foreign matter may be transferred to the back surface of the plate-like workpiece such as a wafer and contaminated.
Therefore, the cleaning of the porous body is generally performed by ultrasonic cleaning with sodium hydroxide or the like, but it is difficult to remove the foreign matter sucked deep inside the porous body. Not only did the removal work take time, but the degree of cleaning was unknown.
Thereby, even if ultrasonic cleaning is performed, foreign matter remains somewhere inside the porous body, so the adsorption of the plate-like workpiece is partially uneven in the plane, and when polishing is performed in this state, There was a problem that uniform processing could not be performed on the entire polished surface of the plate-shaped workpiece, and the quality of the plate-shaped workpiece was varied.

  An object of the present invention is to cope with such a problem, to improve a decrease in the adsorption function due to the suction of foreign matter with a simple structure, and to shift the position of the porous body with respect to the holding member during processing. The purpose is to prevent, to make a communication hole easily.

In order to achieve such an object, the present invention provides a holding member provided with a suction hole leading to a vacuum source, and a porous member provided on the holding member so as to communicate with the suction hole and facing one surface of the plate-like workpiece. And a surface plate provided with a machining surface facing the other surface of the plate-like workpiece and machining the other surface of the plate-like workpiece by relative movement with the holding member, A communication hole communicating with the suction hole of the holding member is extended toward the workpiece facing surface of the porous body, and the suction hole of the holding member is opened linearly in the thickness direction of the holding member. The porous body is fixed to the holding member, and the communication hole is extended from the suction hole toward the porous body .

  In addition to the above-described characteristics, a concave portion is formed in the holding member, and the porous body is disposed in the concave portion.

In the present invention having the above-described features, the communication hole communicating with the suction hole of the holding member is formed in the porous body so as to extend toward the workpiece-facing surface of the porous body. Even if foreign matter is sucked in, the suction force from the vacuum source reaches through the suction hole and the communication hole without decreasing to the workpiece facing surface of the porous body, so the adsorption function of the plate-like workpiece is unlikely to deteriorate. In addition, foreign matter sucked in the vicinity of the surface layer of the workpiece facing surface of the porous member can be easily removed by cleaning, so that the porous body can be returned to the initial state in a short time, so that the structure is simple. Therefore, it is possible to improve the lowering of the adsorption function due to the suction of foreign matter.
As a result, compared to the conventional structure in which the porous body is joined to the suction hole of the holding member, clogging due to foreign matter is less likely to occur, the interval for cleaning foreign matter can be extended, and the plate can be extended over a long period of time. The workpiece can be polished with high accuracy, and the time required for one foreign substance cleaning operation can be shortened, so that a reduction in operating rate can be minimized.
Furthermore, in addition to the conventional one in which the porous body is joined to the holding member so as to communicate with the suction hole 1a, it is possible to improve the processing accuracy of the plate-like workpiece by simply extending the suction hole, The cost of remodeling can be reduced.

Furthermore, when the concave portion is formed in the holding member and the porous body is disposed in the concave portion, the porous body is integrally assembled with the holding member. The position shift of the body can be prevented.
As a result, the polishing accuracy of the plate workpiece can be stabilized.

Further, the suction hole of the holding member is opened linearly in the thickness direction of the holding member, the porous body is fixed to the holding member, and the suction hole is directed to the porous body. When the communication is extended, the communication hole can be extended without removing the porous body from the holding member, so that the communication hole can be easily formed.
As a result, even with the conventional structure in which the porous body is fixed to the concave portion of the holding member, it is possible to easily improve the polishing accuracy of the plate-like workpiece, and to reduce the cost of modification.

It is a longitudinal section showing a polish device concerning an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, a polishing apparatus A according to an embodiment of the present invention includes a holding member 1 provided with a suction hole 1a, and a porous body 2 provided in the holding member 1 so as to communicate with the suction hole 1a. And a surface plate 3 provided with a processed surface 3a so as to face the porous body 2, and a surface (back surface) W1 of the plate-like workpiece W such as a semiconductor silicon wafer is opposed to the porous body 2. The holding member 1 and the porous body 2 and the surface plate 3 are moved relative to each other so that the other surface (surface) W2 of the plate-like workpiece W is pressed against the processing surface 3a to perform mirror polishing. Processing such as (polishing) processing or surface grinding is performed.
That is, the polishing apparatus A according to the embodiment of the present invention is not limited to a so-called polishing apparatus for performing mirror polishing (polishing) processing on the other surface (surface) W2 of the plate-like workpiece W, but also on the other surface of the plate-like workpiece W ( A so-called grinding apparatus for surface grinding the surface (W2) is also included.

The holding member 1 is formed into a plate shape with a material that is hardly chemically attacked, such as ceramics or glass, and has little deformation with respect to aging and load, and a plate-like workpiece W sandwiching a porous body 2 described later. A large number of suction holes 1a are opened toward the porous body 2 at locations opposite to.
One end of the suction hole 1a is connected to a vacuum source (not shown) such as a vacuum pump, and the other end is opened to a boundary surface 1b of the holding member 1 with a porous body 2 described later.
As an example of the suction hole 1a, it is preferable that the diameter of the suction hole 1a is about 1 millimeter or less and a large number of holes are opened at intervals of several millimeters, and the holes are opened linearly in the thickness direction of the holding member 1.
Here, “opening the suction hole 1a linearly toward the thickness direction of the holding member 1” means that the suction hole 1a is opened linearly over the entire length of the holding member 1 in the thickness direction. The suction hole 1a is not only opened in a straight line in a direction perpendicular to the boundary surface 1b of the holding member 1, but also in a direction (diagonal direction) intersecting the boundary surface 1b. It is also included to open a straight line.
Furthermore, it is preferable to form a recess 1c in the surface of the holding member 1 in which a porous body 2 described later is accommodated.

The porous body 2 is made of a material having innumerable fine holes (not shown) inside, for example, porous ceramics, and is formed in a plate shape that is approximately the same size as or larger than the plate-like workpiece W. Communication holes 2 a communicating with the suction holes 1 a of the holding member are respectively extended toward the workpiece facing surface 2 b of the porous body 2.
Although the tip surface 2c of the communication hole 2a is preferably arranged as close as possible to the workpiece facing surface 2b of the porous body 2, it tends to be damaged when approaching the workpiece facing surface 2b. It is preferable to adjust the distance from the tip surface 2c to the workpiece facing surface 2b according to the material strength.
Furthermore, when the porous body 2 is fixed to the boundary surface 1b of the holding member 1 and the suction hole 1a is opened linearly in the thickness direction of the holding member 1, It is preferable to extend the communication hole 2 a from the suction hole 1 a side toward the porous body 2.
That is, the connecting hole 2a is opened in a straight line that is continuous with the suction hole 1a by performing a drilling process from the holding member 1 toward the porous body 2 along the suction hole 1a.

  The surface plate 3 is provided with a processing surface 3a along a surface facing the holding member 1 and the porous body 2 by, for example, detachably stretching a polishing cloth or the like. By being configured to move relative to the porous body 2 and further supplying a polishing abrasive liquid (slurry) between the other surface W2 of the plate-like workpiece W and the processing surface 3a as necessary, The machining surface 3a is configured to come into pressure contact with the other surface W2 of the plate-like workpiece W at a predetermined pressure.

According to such a polishing apparatus A according to the embodiment of the present invention, for example, by starting operation of a vacuum source such as a vacuum pump, the suction force is applied to the workpiece facing surface of the porous body 2 via the suction hole 1a and the communication hole 2a. 2b, so that one surface W1 of the plate-like workpiece W such as a wafer is sucked and held, and the other surface W2 of the plate-like workpiece W is pressed against the processing surface 3a by relative movement with the surface plate 3 to perform mirror polishing or grinding. Processed.
Foreign matters such as grinding dust (cutting chips) and dust generated by this processing are sucked into the inside of the fine holes of the porous body 2.
However, since the suction force from the vacuum source reaches the workpiece facing surface 2b of the porous body 2 through the suction hole 1a and the communication hole 2a without decreasing, some foreign matter is a fine hole in the porous body 2. The foreign matter sucked in the vicinity of the surface layer of the workpiece facing surface 2b of the porous member 2 is not easily deteriorated by the ultrasonic cleaning with, for example, sodium hydroxide. Since it can be easily removed, the porous body 2 can be returned to the initial state in a short time.
Thereby, although it is a simple structure, the fall of the adsorption | suction function by suction of a foreign material can be improved, and the plate-shaped workpiece | work W can be grind | polished with high precision over a long period of time.
Next, an embodiment of the present invention will be described with reference to the drawings.

  In this embodiment, as shown in FIG. 1, the holding member 1 is a disk-shaped top ring that rotates in the rotation direction of the surface plate 3 about the rotation shaft 1 d, and is recessed on the boundary surface 1 b with the porous body 2. 1c is formed and a disk-shaped porous body 2 is housed and arranged, and is fixed with an adhesive such as glass or synthetic resin, and the turntable 3 rotates around the drive shaft 3b. The case where the non-diffused surface of the diffusion wafer, for example, as a plate-like workpiece W is polished to a high-quality mirror surface with high flatness and no scratches or impurities by the rotation of the top ring and the rotation of the turntable is shown.

In the example shown in FIG. 1, the suction hole 1 a and the communication hole 2 a are opened linearly in a direction orthogonal to the boundary surface 1 b between the holding member 1 and the porous body 2.
Although not shown as another example, the suction hole 1a and the communication hole 2a can be opened linearly in a direction (diagonal direction) intersecting the boundary surface 1b.
Furthermore, the thickness of the tip surface 2c of the communication hole 2a from the tip surface 2c to the workpiece facing surface 2b is about ½ or less, more specifically １ ／ or less of the entire porous body 2 thickness. Are arranged close to the workpiece facing surface 2b.

  Further, in the example shown in FIG. 1, only one porous body 2 and one plate-like workpiece W are shown with respect to the top ring serving as the holding member 1, and the other porous body 2 and the plate-like workpiece W are shown. Although omitted, a plurality of porous bodies 2 and a corresponding number of plate-like workpieces W can be arranged at predetermined intervals in the circumferential direction of the top ring.

According to such a polishing apparatus A according to an embodiment of the present invention, by forming the recess 1c in which the porous body 2 is accommodated on the boundary surface 1b of the top ring serving as the holding member 1 and fixing with an adhesive, Since the porous body 2 is integrally assembled with the concave portion 1c of the holding member 1, the porous member 2 is porous with respect to the holding member 1 during polishing by rotation of the top ring serving as the holding member 1 or rotation of the turntable serving as the surface plate 3. The mass 2 is not misaligned.
Thereby, there is an advantage that the polishing accuracy of the plate-like workpiece W can be stabilized.

Further, when the hole is formed from the holding member 1 toward the porous body 2 along the suction hole 1a and the communication hole 2a is extended in a straight line continuous with the suction hole 1a, the holding member 1 The connecting hole 2a can be extended without removing the porous body 2 from the recess 1c.
Accordingly, there is an advantage that the communication hole 2a can be easily created even when the porous body 2 remains fixed to the recess 1c of the holding member 1.

In the embodiment shown above, the holding member 1 is a top ring and the surface plate 3 is a turntable. By rotating the top ring and rotating the turntable, the plate-like workpiece W is, for example, a non-diffusion surface of a diffusion wafer. However, the present invention is not limited to this, and the surface of a wafer other than the diffusion wafer as the plate-like workpiece W is mirror-polished, or the surface of the diffusion wafer is different from the non-diffusion surface or the diffusion wafer. One side of a wafer or the like may be ground and removed to a desired thickness in a flat shape.
In these cases, the same effects as those of the above-described embodiment can be obtained.
Further, a concave portion 1c is formed in the boundary surface 1b of the holding member 1 and the disk-like porous body 2 is accommodated and fixed, for example, with an adhesive such as glass or synthetic resin. The porous body 2 may be fixed with an adhesive without forming the recess 1 c in the member 1.

DESCRIPTION OF SYMBOLS 1 Holding member 1a Suction hole 1c Recessed part 2 Porous body 2a Communication hole 2b Workpiece facing surface 3 Surface plate 3a Processing surface W Plate-like work W1 One side W2 Other side

Claims (2)

A holding member provided with a suction hole leading to a vacuum source;
A porous body provided on the holding member so as to communicate with the suction hole and facing one surface of the plate-like workpiece;
A processing surface provided opposite to the other surface of the plate-like workpiece, and a surface plate for processing the other surface of the plate-like workpiece by relative movement with the holding member,
A communication hole communicating with the suction hole of the holding member is formed in the porous body so as to extend toward the workpiece facing surface of the porous body ,
The suction hole of the holding member is opened linearly in the thickness direction of the holding member, the porous body is fixed to the holding member, and the suction hole is directed toward the porous body from the suction hole. A polishing apparatus characterized in that a communication hole is formed as an extension .   The polishing apparatus according to claim 1, wherein a concave portion is formed in the holding member, and the porous body is disposed in the concave portion.

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