VERTICAL TYPE SURFACE GRINDING MACHINE

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2024-005938 filed on Jan. 18, 2024, the entire disclosure of which is incorporated by reference herein.

BACKGROUND

The present disclosure relates to a vertical type surface grinding machine.

Patent Document 1 (International Patent Publication No. WO2017/094646) discloses a machining device as an example of a vertical type surface grinding machine. Specifically, the machining device disclosed in Patent Document 1 includes an index table, a column, a rough grinder, and a fine grinder.

Here, the index table is provided with at least a rough grinding stage and a fine grinding stage, and moves a wafer from the rough grinding stage to the fine grinding stage. The column is arranged over the rough grinding stage and the fine grinding stage. The rough grinder is provided on a portion of the column above the rough grinding stage to roughly grind the wafer. The fine grinder is provided on a portion of the column above the fine grinding stage to finely grind the wafer.

Further, according to Patent Document 1 described above, the column has a gate shape arranged over the rough grinding stage and the fine grinding stage. The rough grinder and the fine grinder are arranged side by side along the gate shape.

According to Patent Document 1 described above, a wafer can be roughly and finely ground in a continuous manner with high quality, with reduced shaft inclination of a rough grinder and a fine grinder resulting from a perpendicular reaction force generated during grinding.

SUMMARY

For example, if a member for a semiconductor, such as a wafer, is an object to be ground (a workpiece), a grinding wheel needs to be rotated by a higher power motor. A high power motor is usually larger and heavier than a low power motor.

In this case, if the rough grinder and the fine grinder are arranged side by side as in Patent Document 1 described above, large and heavy motors as described above are also arranged side by side. This may increase the size of the column in the direction of arrangement of the motors. The increase in the size of the column may lead to an increase in the pitch between chucks located below the column and in turn an increase in the size of the index table.

However, the column in Patent Document 1 described above is supported at both ends of the gate shape (i.e., at two points). If large and heavy motors are suspended on the frame of the column, it may cause distortion of the column or may cause collapse of the column.

If a wafer is ground using a high power motor, a high load can be placed on the index table as well. In this case, a large index table is unfavorable in view of the table rigidity and unsuitable when a high load is placed on the index table.

In addition, the increase in the size of the column and the index table is unfavorable in view of the machining accuracy in the first place.

It is therefore an object of the present disclosure to achieve both of higher motor power and more compact column and index table.

A first aspect of the present disclosure relates to a vertical type surface grinding machine configured to grind a surface of a workpiece. The vertical type surface grinding machine includes: an index table having at least two chucks on each of which the workpiece is mounted, the index table having a central axis extending in an upward/downward direction and being configured to move the two chucks rotationally between a first position and a second position arranged in a circumferential direction around the central axis; a column arranged over the index table; a first grinding wheel mechanism supported by the column and configured to machine the workpiece mounted on one of the chucks located at the first position; and a second grinding wheel mechanism supported by the column and configured to machine the workpiece mounted on another one of the chucks located at the second position.

According to the first aspect, the column includes, in a plan view along the central axis: a lateral side portion extending along a direction of arrangement of the first and second positions; and a vertical side portion extending from a central portion of the lateral side portion perpendicularly to the lateral side portion, the column being supported from below by both ends of the lateral side portion and at least one end of the vertical side portion, the first and second grinding wheel mechanisms each including: a spindle driven rotationally by a motor so as to rotate around a predetermined rotation axis; and a feeding mechanism configured to move the spindle in an axial direction along the rotation axis, each of the first and second grinding wheel mechanisms being supported by the lateral side portion and the vertical side portion while arranged like a bridge between the lateral side portion and the vertical side portion, each of the feeding mechanisms of the first and second grinding wheel mechanisms being located at a corner at which the lateral side portion and the vertical side portion intersect.

According to the first aspect, the first and second grinding wheel mechanisms are arranged like a bridge between the lateral side portion and the vertical side portion. Taking the direction of extension of the vertical side portion into account, it is not that the first and second grinding wheel mechanisms are arranged side by side along the lateral side portion but that they are arranged obliquely with respect to the extension direction of the lateral side portion.

The oblique arrangement of the first and second grinding wheel mechanisms allows the lateral side portion to be shorter than the side-by-side arrangement of the first and second grinding wheel mechanisms. It is thus possible to make the column more compact, reduce the pitch between the chucks, and in turn make the index table more compact, even if high power motors are used.

The index table made more compact contributes to improvement in the table rigidity. The improvement in the table rigidity is advantageous in grinding a workpiece using a high power motor. In addition, the reduction in the size of each of the column and the index table contributes to ensuring machining accuracy.

Furthermore, according to the first aspect, the column is supported at at least three points: both ends of the lateral side portion and one end of the vertical side portion. Thus, even if a large and heavy motor is suspended on the column, it is possible to reduce distortion and collapse of the column.

Furthermore, according to the first aspect, the feeding mechanisms moving the spindles are located at corners at which the lateral side portion and the vertical side portion intersect. By arranging the feeding mechanisms in this manner, it is possible to arrange the feeding mechanisms near the center of gravity of the column.

Thus, even if distortion occurs in the column, it is possible to reduce the collapse of the column due to the distortion. As a result, it is possible to ensure the machining accuracy as described above and reduce the collapse of the column even if the high power motor is used.

According to a second aspect of the present disclosure, the lateral side portion may be supported from below by first and second supporting portions located at both ends of the lateral side portion in the direction of arrangement, the vertical side portion may be supported from below via a third supporting portion located at one end of the vertical side portion opposite to the lateral side portion, the spindle of the first grinding wheel mechanism may be located at a central portion of a straight line connecting the first supporting portion and the third supporting portion in the plan view, the spindle of the second grinding wheel mechanism may be located at a central portion of a straight line connecting the second supporting portion and the third supporting portion in the plan view, and each of the feeding mechanisms of the first and second grinding wheel mechanisms may be located inside a triangle connecting the first supporting portion, the second supporting portion, and the third supporting portion in the plan view.

According to the second aspect, by arranging the feeding mechanisms inside the triangle, it is possible to make the feeding mechanisms closer to the center of gravity of the column as compared to the configuration in which the feeding mechanisms are located outside the triangle. This configuration is further advantageous in reducing the collapse of the column.

Further, by positioning the spindle at the central portion of the straight line according to the second aspect, it is possible to distribute the load, applied to the column by the spindle, between the lateral side portion and the vertical side portion in a balanced manner. The spindles can thus be supported stably.

According to a third aspect of the present disclosure, the first and second grinding wheel mechanisms may each include a pair of linear guides configured to support the spindle on the column and arranged along a straight line passing through the rotation axis of the spindle in the plan view, one of the pair of linear guides is supported by the lateral side portion, and another one of the pair of linear guides is supported by the vertical side portion.

According to the third aspect, it is possible to arrange the spindle and the pair of linear guides on the same straight line in the plan view. It is thus possible to reduce the collapse of the spindles due to their own weight.

There are concerns that the column increases in size if the spindle and the pair of linear guides are arranged on the same straight line in the plan view. However, such an increase in size can be reduced as much as possible by arranging the first and second grinding wheel mechanisms obliquely as in the first aspect.

That is, the third aspect is more effective when combined with the first aspect.

According to a fourth aspect of the present disclosure, a pedestal supporting the index table may include, in the plan view: a first chamfer cut along the straight line connecting the first supporting portion and the third supporting portion; a second chamfer cut along the straight line connecting the second supporting portion and the third supporting portion; and an operation surface located between the first chamfer and the second chamfer and extending along the lateral side portion.

According to the fourth aspect, a space located in front of the first chamfer can be used for maintenance of the first grinding wheel mechanism. A space located in front of the second chamfer can be used for maintenance of the second grinding wheel mechanism. It is possible to keep the spaces larger by the oblique arrangement of the first grinding wheel mechanism and the second grinding wheel mechanism.

This configuration results in the oblique extension of the first chamfer and the second chamfer, which makes it possible to ensure the operation surface between the first chamfer and the second chamfer. A space located in front of the operation surface can be used, for example, as an installation space for the operation panel. The usability of the vertical type surface grinding machine is therefore improved.

According to a fifth aspect of the present disclosure, the index table may have three chucks on each of which the workpiece is mounted, the index table being configured to move the three chucks rotationally among the first position and the second position arranged in the circumferential direction and a third position at which the workpiece is replaced, the lateral side portion may extend in between the third position and the first and second positions in the plan view, and the vertical side portion may extend in a direction away from the third position in the plan view.

A workpiece (e.g., a wafer) is usually attached to and detached from the chuck that has moved to the third position, by a robot arm or any other component. The vertical side portion is therefore extended in a direction away from the third position, as in the fifth aspect, to make it possible to reduce the interference between the vertical side portion and the robot arm during the attachment and detachment of the workpiece. The usability of the vertical type surface grinding machine is therefore improved.

As can be seen from the above description, according to the present disclosure, it is possible to achieve both of higher motor power and more compact column and index table.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view exemplifying a vertical type surface grinding machine.

FIG. 2 is another perspective view exemplifying the vertical type surface grinding machine.

FIG. 3 is a plan view exemplifying the vertical type surface grinding machine.

FIG. 4 is a plan view exemplifying an index table.

FIG. 5A is a plan view exemplifying a column.

FIG. 5B is another plan view exemplifying the column.

FIG. 6 is a longitudinal sectional view exemplifying first and second grinding mechanisms.

FIG. 7 shows diagrams for illustrating first and second chamfers.

FIG. 8 is a diagram illustrating a variation of the vertical type surface grinding machine, and corresponds to FIG. 3.

DETAILED DESCRIPTION

An embodiment of the present disclosure will be described below with reference to the drawings. The following description is an example.

(General Configuration)

FIG. 1 and FIG. 2 are perspective views exemplifying a vertical type surface grinding machine 1. FIG. 3 is a plan view exemplifying the vertical type surface grinding machine 1. FIG. 4 is a plan view exemplifying an index table 2. FIG. 5A and FIG. 5B are plan views exemplifying a column 5. FIG. 6 is a longitudinal sectional view exemplifying first and second grinding mechanisms 6 and 7. FIG. 7 illustrates first and second chamfers 10a and 10b.

The vertical type surface grinding machine 1 is a grinding device which grinds a surface on one side of a wafer for a semiconductor. Specifically, as illustrated in FIG. 1, FIG. 2, and FIG. 3, the vertical type surface grinding machine 1 includes a bed 3, an index table 2, a column base 4, a column 5, a first grinding mechanism 6, a second grinding mechanism 7, a first guide pair 8, a second guide pair 9, and an operation panel 100. The vertical type surface grinding machine 1 may be hereinafter simply referred to as the “grinding machine 1.”

The wafer for a semiconductor as used herein is an example of a workpiece in this embodiment. The first grinding mechanism 6 is an example of a first grinding wheel mechanism, and the second grinding mechanism 7 is an example of a second grinding wheel mechanism.

(Bed)

The bed 3 is installed on a foundation (installation surface), such as a floor surface of a factory, on which the grinding machine 1 is installed. The bed 3 has a thick plate shape extending in the upward/downward direction, and has one or a plurality of legs to support the index table 2 and the column base 4 from below. The bed 3 supports the column 5, the first and second grinding mechanisms 6 and 7, and other components via the index table 2 and the column base 4.

The upward/downward direction as used herein refers to a direction along a central axis Ac extending perpendicularly to the installation surface. Hereinafter, this direction may be referred to also as the “axial direction.” In the following description, a direction of circulation around the central axis Ac is referred to as the “circumferential direction,” and a direction extending radially from the central axis Ac is referred to as the “radial direction.” In the following description, a “plan view” refers to a view from above along the axial direction.

(Index Table)

The index table 2 has at least two chucks 21 on each of which a wafer is mounted. The index table 2 rotationally moves each of the at least two (three in this embodiment) chucks 21 between a rough grinding position P1 and a fine grinding position P2 arranged in the circumferential direction around the central axis Ac (see FIG. 2 and FIG. 4 for the rough grinding position P1 and the fine grinding position P2).

To be specific, the index table 2 has a substantially columnar shape extending in the upward/downward direction, and is disposed at the center of the bed 3. The central axis Ac extends so as to pass through the center of this columnar shape. The index table 2 has a built-in first motor (not shown) for rotating the entirety of the plurality of chucks 21.

As illustrated in FIG. 4, the index table 2 includes three chucks 21 in this embodiment. Each of the three chucks 21 is configured to vacuum and hold the wafer. The three chucks 21 are arranged at equal intervals of 120° in the circumferential direction.

To be specific, each chuck 21 is configured as a chuck table in the shape of a disk. The outer diameter of the chuck table is substantially the same as the outer diameter of the wafer. The chuck table is made of porous ceramics, and is connected to a vacuum source (not shown). Each chuck 21 vacuums and holds the wafer by negative pressure generated by the vacuum source.

Each chuck 21 rotates around the central axis Ac by the motor. This rotation allows each of the three chucks 21 to move rotationally among a replacement position P3 where the wafer is attached or detached, the rough grinding position P1 where the wafer is ground roughly, and the fine grinding position P2 where the wafer is ground finely (see FIG. 1 and FIG. 4 for the replacement position P3).

The rough grinding position P1 is an example of a “first position” in this embodiment; the fine grinding position P2 is an example of a “second position” in this embodiment; and the replacement position P3 is an example of a “third position” in this embodiment. These positions are arranged in the order of the replacement position P3, the rough grinding position P1, and the fine grinding position P2 along the clockwise direction.

A second motor is connected to each of the chucks 21 for driving the chuck 21. Driving of this second motor allows each of the chucks 21 to rotate around the chuck rotation axis Aw passing through the center of the disk shape of the chuck 21 independently from one another. The direction of rotation at this time can be changed as appropriate.

(Column Base)

The column base 4 is disposed on the bed 3, similarly to the index table 2. The column base 4 supports the column 5 from below. The column base 4 supports the first and second grinding mechanisms 6 and 7 and the first and second guide pairs 8 and 9 via the column 5.

Specifically, the column base 4 according to this embodiment has a U shape surrounding the index table 2 from lateral directions, and the upper surface of the U shape supports the column 5 from below. For this purpose, as illustrated in FIG. 4, the upper surface of the column base 4 is provided with a first supporting portion 41, a second supporting portion 42, and a third supporting portion 43.

The column base 4 does not have to be provided in addition to the bed 3. The bed 3 and the column base 4 may be integrated together. Regardless of whether the bed 3 and the column base 4 are separate or integrated, they may be collectively referred to as a “pedestal 10.”

(Column)

The column 5 is arranged over the index table 2. The column 5 is supported not by the index table 2 but by the column base 4 from below.

Here, the column 5 has a lateral side portion 51 and a vertical side portion 52 as illustrated in FIG. 5A. The column 5 has a T shape formed by the lateral side portion 51 and the vertical side portion 52.

As will be described later in a variation, the lateral side portion 51 and the vertical side portion 52 do not have to form a T shape. The vertical side portion 52 may be protruded from the lateral side portion 51 to form, so to speak, a cross shape.

The lateral side portion 51 extends along the direction of arrangement of the rough grinding position P1 and the fine grinding position P2 in the plan view in FIG. 5A. The “direction of arrangement” as used herein is the longitudinal direction of the lateral side portion 51. For example, the lateral direction of the sheet of FIG. 5A corresponds to the direction of arrangement in the figure.

To be specific, the lateral side portion 51 extends in between the rough and fine grinding positions P1 and P2 and the replacement position P3 in the plan view. The lateral side portion 51 is located above the rough grinding position P1, the fine grinding position P2, and the replacement position P3, but does not completely cover the chucks 21 arranged at these three positions P1 to P3 in the plan view. As illustrated in FIG. 4, at least part of each of the three chucks 21 is exposed upward.

To be more specific, as illustrated in FIG. 4, the lateral side portion 51 is supported from below by the first and second supporting portions 41 and 42 located at both ends in the direction of arrangement. Here, the first supporting portion 41 supports one longitudinal end 51a of the lateral side portion 51 from below. The second supporting portion 42 supports the other longitudinal end 51b of the lateral side portion 51 from below. The one longitudinal end 51a may be called a “first end 51a,” and the other longitudinal end 51b may be called a “second end 51b” (see FIG. 4).

The vertical side portion 52 extends in between the rough grinding position P1 and the fine grinding position P2, from a central portion 51c of the lateral side portion 51 perpendicularly to the lateral side portion 51. The direction of extension of the vertical side portion 52 is the width direction of the lateral side portion 51. For example, the top/bottom direction of the sheet of FIG. 5A corresponds to the direction of extension of the vertical side portion 52 in this figure.

The central portion 51c of the lateral side portion 51 is a central portion of the lateral side portion 51 in the direction of arrangement. For example, as illustrated in FIG. 5A, the central portion 51c may be a portion including a region where a symmetry line As, described later, passes.

To be specific, the vertical side portion 52 extends in a direction away from the replacement position P3 in the plan view. The vertical side portion 52 is located above the rough grinding position P1 and the fine grinding position P2, but does not completely cover the chucks 21 arranged at these two positions P1 and P2 in the plan view. As illustrated in FIG. 4, at least part of each of the two chucks 21 is exposed upward. The vertical side portion 52 is not located above the replacement position P3, and is configured not to cover the chuck 21 arranged at the replacement position P3 from above.

To be more specific, the vertical side portion 52 is supported from below by the third supporting portion 43 located at one end of the vertical side portion 52 opposite to the lateral side portion 51. Here, the third supporting portion 43 supports one longitudinal end 52a of the vertical side portion 52 from below. The one longitudinal end 52a of the vertical side portion 52 may be simply called a “third end 52a.”

As illustrated in FIG. 5B, in this embodiment, the first supporting portion 41, the second supporting portion 42, and the third supporting portion 43 form a right-angled triangle whose hypotenuse is the phantom line connecting the first supporting portion 41 and the second supporting portion 42 in the plan view.

The column 5 is mirror symmetric with respect to the straight line passing through the vertical side portion 52 (the symmetry line As in FIG. 5A) in the plan view. In other words, the right-angled triangle described above can also be regarded as a right isosceles triangle in which the length of a line segment connecting the first supporting portion 41 and the third supporting portion 43 and the length of a line segment connecting the second supporting portion 42 and the third supporting portion 43 are equal to each other.

As illustrated in FIG. 5A and FIG. 5B, in the plan view, a phantom line (a phantom plane) connecting the first supporting portion 41 and the second supporting portion 42 will be hereinafter called a “hypotenuse Lh”; a phantom line (a phantom plane) connecting the first supporting portion 41 and the third supporting portion 43 will be called a “first attachment line L1”; and a phantom line (a phantom plane) connecting the second supporting portion 42 and the third supporting portion 43 will be called a “second attachment line L2.”

As can be seen, the column 5 according to this embodiment is supported at the three points around the index table 2 on the upper surface of the column base 4, and arranged over the index table 2. As indicated by the hatched region in FIG. 5A, the column 5 has a T shape formed by the lateral side portion 51 and the vertical side portion 52 in the plan view. The lower surfaces of the end portions of the lateral line (the lateral side portion 51) and the vertical line (the vertical side portion 52) of the T shape are supported by the first supporting portion 41 to the third supporting portion 43 from below. A triangle connecting the three supporting portions 41 to 43 or the end portions supported by these supporting portions is a right isosceles triangle.

Instead of the above definition, the definition can be that the following definition: the first end 51a supported by the first supporting portion 41, the second end 51b supported by the second supporting portion 42, and the third end 52a supported by the third supporting portion 43 form a right-angled triangle whose hypotenuse is the phantom line connecting the first end 51a and the second end 51b.

In this case, a phantom line (a phantom plane) connecting the first end 51a and the second end 51b will be called the “hypotenuse Lh”; a phantom line (a phantom plane) connecting the first end 51a and the third end 52a will be called the “first attachment line L1”; and a phantom line (a phantom plane) connecting the second end 51b and the third end 52a will be called the “second attachment line L2.”

(First Grinding Mechanism)

The first grinding mechanism 6 is supported by the column 5. The first grinding mechanism 6 machines (roughly grinds) the wafer mounted on the chuck 21 located at the rough grinding position P1.

As illustrated in FIG. 2, FIG. 3 and FIG. 5A, the first grinding mechanism 6 includes a first spindle 61 and a first feeding mechanism 62. The first spindle 61 rotates around a predetermined first rotation axis As1. The first feeding mechanism 62 moves the first spindle 61 in the axial direction along the first rotation axis As1.

Specifically, as illustrated in FIG. 6, the first spindle 61 includes a spindle case 61a, a grinding wheel spindle case 61b, and a grinding wheel 61c. A part of FIG. 6 corresponding to the first spindle 61 is a vertical sectional view taken along the straight line L3 shown in FIG. 5A and FIG. 5B.

The spindle case 61a has a cylindrical shape which houses the grinding wheel spindle case 61b and the grinding wheel 61c. The grinding wheel spindle case 61b houses a grinding wheel spindle that rotatably supports the grinding wheel 61c, and a drive motor 61d that drives the grinding wheel spindle. The grinding wheel 61c is attached to the lower end of the grinding wheel spindle. The grinding wheel 61c is, for example, a cup-shaped grinding wheel having grinding segments arranged annularly on the bottom surface of a disk-shaped base material. The grinding wheel spindle and the grinding wheel 61c rotate around the first rotation axis As1. The direction of this rotation can be changed as appropriate.

On the other hand, the first feeding mechanism 62 includes a feed motor 62a and a first ball screw 62b. The feed motor 62a rotates the first ball screw 62b to move the spindle case 61a upward and downward. The first ball screw 62b functions as a feed rod for the first spindle 61. An attachment position of the first ball screw 62b, which is also the attachment position of the first feeding mechanism 62, will be described later.

In addition, the first spindle 61 is supported by a balance cylinder (not shown) by a vertically upward force. This prevents the weight of the first spindle 61 from acting on the first ball screw 62b. Further, the grinding wheel spindle case 61b can adjust its own inclination with respect to the spindle case 61a.

The first grinding mechanism 6 also includes a pair of linear guides (a first guide pair 8) supporting the first spindle 61 on the column 5. The first guide pair 8 includes a first linear guide 81 and a second linear guide 82. The first and second linear guides 81 and 82 support the spindle case 61a from both sides. Attachment positions of the first and second linear guides 81 and 82 will be described later.

Both of the first and second linear guides 81 and 82 extend in the upward/downward direction. The first and second linear guides 81 and 82 fix the spindle case 61a of the first spindle 61 to the column 5 such that the spindle case 61a can be displaced in the upward/downward direction. The first and second linear guides 81 and 82 guide the upward and downward movements of the spindle case 61a.

In this embodiment, the first grinding mechanism 6 is supported by the lateral side portion 51 and the vertical side portion 52 while arranged like a bridge between the lateral side portion 51 and the vertical side portion 52. Specifically, the first grinding mechanism 6 is supported by the first end 51a of the lateral side portion 51 and the third end 52a of the vertical side portion 52.

In other words, as illustrated in FIG. 5B, the first spindle 61 is located at a central portion of the straight line (the first attachment line L1) connecting the first supporting portion 41 and the third supporting portion 43 in the plan view. Specifically, the first rotation axis As1 of the first spindle 61 is located at the central portion of the first attachment line L1.

To achieve such arrangement, the first linear guide 81 according to this embodiment is supported by the lateral side portion 51 (in particular, the first end 51a). On the other hand, the second linear guide 82 according to this embodiment is supported by the vertical side portion 52 (in particular, the third end 52a). The first spindle 61 is thus supported by the lateral side portion 51 and the vertical side portion 52.

Furthermore, the first and second linear guides 81 and 82 are arranged along the straight line passing through the first rotation axis As1 (the first attachment line L1) in the plan view of FIG. 5A, for example.

In other words, the first and second linear guides 81 and 82 and the first rotation axis As1 are arranged on the same straight line, along the first attachment line L1. That is, the first grinding mechanism 6 according to this embodiment is supported along an oblique line with respect to the directions in which the lateral side portion 51 and the vertical side portion 52 extend.

As illustrated in FIG. 5B, the attachment position of the first linear guide 81 is adjacent to the first supporting portion 41 in the plan view. The first linear guide 81 is supported by the first end 51a.

The attachment position of the second linear guide 82 is adjacent to the third supporting portion 43 in the plan view. The second linear guide 82 is supported by the third end 52a.

(Second Grinding Mechanism)

The second grinding mechanism 7 is supported by the column 5. The second grinding mechanism 7 machines (finely grinds) the wafer mounted on the chuck 21 located at the fine grinding position P2.

The configuration of the second grinding mechanism 7 is substantially the same as the configuration of the first grinding mechanism 6 except that the second grinding mechanism 7 is symmetrically placed to the first grinding mechanism 6 (in particular, mirror symmetric with respect to the symmetry line As).

For example, as illustrated in FIG. 2, FIG. 3, and FIG. 5A, the second grinding mechanism 7 includes a second spindle 71 and a second feeding mechanism 72. The second spindle 71 rotates around a predetermined second rotation axis As2. The second feeding mechanism 72 moves the second spindle 71 in the axial direction along the second rotation axis As2.

Specifically, as illustrated in FIG. 6, the second spindle 71 includes a spindle case 71a, a grinding wheel spindle case 71b, and a grinding wheel 71c. A part of FIG. 6 corresponding to the second spindle 71 is a vertical sectional view taken along the straight line L4 shown in FIG. 5A and FIG. 5B.

The spindle case 71a houses the grinding wheel spindle case 71b and the grinding wheel 71c. The grinding wheel spindle case 71b houses a grinding wheel spindle that rotatably supports the grinding wheel 71c, and a drive motor 71d that drives the grinding wheel spindle. The grinding wheel 71c is attached to the lower end of the grinding wheel spindle.

On the other hand, the second feeding mechanism 72 includes a feed motor 72a and a second ball screw 72b. The feed motor 72a rotates the second ball screw 72b to move the spindle case 71a upward and downward. The second ball screw 72b functions as a feed rod for the second spindle 71.

The second grinding mechanism 7 also includes a pair of linear guides (a second guide pair 9) supporting the second spindle 71 on the column 5. The second guide pair 9 includes a third linear guide 91 and a fourth linear guide 92. The third and fourth linear guides 91 and 92 support the spindle case 71a of the second grinding mechanism 7 from both sides. Attachment positions of the third and fourth linear guides 91 and 92 will be described later.

Both of the third and fourth linear guides 91 and 92 extend in the upward/downward direction. The third and fourth linear guides 91 and 92 fix the spindle case 71a of the second spindle 71 to the column 5 such that the spindle case 71a can be displaced in the upward/downward direction. The third and fourth linear guides 91 and 92 guide the upward and downward movements of the spindle case 71a.

Similarly to the first grinding mechanism 6, the second grinding mechanism 7 according to this embodiment is supported by the lateral side portion 51 and the vertical side portion 52 while arranged like a bridge between the lateral side portion 51 and the vertical side portion 52 in the plan view. Specifically, the second grinding mechanism 7 is supported by the second end 51b of the lateral side portion 51 and the third end 52a of the vertical side portion 52.

In other words, as illustrated in FIG. 5B, the second spindle 71 is located at a central portion of the straight line (the second attachment line L2) connecting the second supporting portion 42 and the third supporting portion 43 in the plan view. Specifically, the second rotation axis As2 of the second spindle 71 is located at the central portion of the second attachment line L2.

To achieve such arrangement, the third linear guide 91 according to this embodiment is supported by the lateral side portion 51 (in particular, the second end 51b). On the other hand, the fourth linear guide 92 according to this embodiment is supported by the vertical side portion 52 (in particular, the third end 52a). The second spindle 71 is thus supported by the lateral side portion 51 and the vertical side portion 52.

The positions where the third linear guide 91 and the fourth linear guide 92 are supported are mirror symmetric to the positions where the first linear guide 81 and the second linear guide 82 are supported, with respect to the symmetry line As passing through the vertical side portion 52.

The third and fourth linear guides 91 and 92 are arranged along the straight line passing through the second rotation axis As2 (the second attachment line L2) in the plan view of FIG. 5A, for example.

In other words, the third and fourth linear guides 91 and 92 and the second rotation axis As2 are arranged on the same straight line, along the second attachment line L2. That is, the second grinding mechanism 7 according to this embodiment is supported along an oblique line with respect to both of the lateral side portion 51 and the vertical side portion 52. In addition, the second grinding mechanism 7 is arranged so as to be to be mirror symmetric to the first grinding mechanism 6 with respect to the straight line passing through the vertical side portion 52.

As illustrated in FIG. 5B, the attachment position of the third linear guide 91 is adjacent to the second supporting portion 42 in the plan view. The third linear guide 91 is supported by the second end 51b.

The attachment position of the fourth linear guide 92 is adjacent to the third supporting portion 43 in the plan view. That is, the third supporting portion 43 is located between the attachment position of the fourth linear guide 92 and the attachment position of the second linear guide 82 in the plan view. In other words, the attachment position of the fourth linear guide 92 and the attachment position of the second linear guide 82 are located on both sides of the third supporting portion 43 in the plan view. The fourth linear guide 92 is supported by the third end 52a.

(Layout of First and Second Feeding Mechanisms)

As illustrated in FIG. 5B, the first feeding mechanism 62 of the first grinding mechanism 6 is located at a first corner 53 at which the lateral side portion 51 and the vertical side portion 52 intersect. The first corner 53 is a corner that faces the first attachment line L1 in the plan view.

Specifically, the first ball screw 62b of the first feeding mechanism 62 is arranged at the first corner 53. As illustrated in FIG. 5B, the first ball screw 62b is arranged such that the straight line L3 connecting the central axis Ab1 of the first ball screw 62b and the first rotation axis As1 is perpendicular to the first attachment line L1.

Similarly, the second feeding mechanism 72 of the second grinding mechanism 7 is located at a second corner 54 at which the lateral side portion 51 and the vertical side portion 52 intersect. The second corner 54 is a corner that faces the second attachment line L2 in the plan view.

Specifically, the second ball screw 72b of the second feeding mechanism 72 is arranged at the second corner 54. As illustrated in FIG. 5B, the second ball screw 72b is arranged such that the straight line L4 connecting the central axis Ab2 of the second ball screw 72b and the second rotation axis As2 is perpendicular to the second attachment line L2.

In other words, the first and second feeding mechanisms 62 and 72 (in particular, the first and second ball screws 62b and 72b) can be regarded as being located inside a triangle (a right isosceles triangle) T connecting the first supporting portion 41, the second supporting portion 42, and the third supporting portion 43 in the plan view. As indicated by the dashed line in FIG. 5B, the triangle T can be regarded as a triangle connecting the first end 51a, the second end 51b, and the third end 52a.

More specifically, the first ball screw 62b is located inside one of halves of the triangle T divided by the symmetry line As (the right one in the sheet of FIG. 5B), and the second ball screw 72b is located inside the other one of the halves of the triangle T divided by the symmetry line As (the left one in the sheet of FIG. 5B). The arrangement of the first and second ball screws 62b and 72b inside the triangle T contributes to making the entire grinding machine 1 including the index table 2 more compact.

In addition, as illustrated in FIG. 4, the chuck rotation axis Aw is closer to the central axis Ac of the index table 2 than the first rotation axis As1. In other words, in the plan view of FIG. 4, the distance between the chuck rotation axis Aw and the central axis Ac of the index table 2 is shorter than the distance between the first rotation axis As1 and the central axis Ac.

The central axis Ab1 of the first ball screw 62b is closer to the central axis Ac of the index table 2 than the associated chuck rotation axis Aw. In other words, in the plan view of FIG. 4, the distance between the central axis Ab1 of the first ball screw 62b and the central axis Ac of the index table 2 is shorter than the distance between the chuck rotation axis Aw and the central axis Ac.

Similarly, as illustrated in FIG. 4, the chuck rotation axis Aw is closer to the central axis Ac of the index table 2 than the second rotation axis As2. In other words, in the plan view of FIG. 4, the distance between the chuck rotation axis Aw and the central axis Ac of the index table 2 is shorter than the distance between the second rotation axis As2 and the central axis Ac.

The central axis Ab2 of the second ball screw 72b is closer to the central axis Ac of the index table 2 than the associated chuck rotation axis Aw. In other words, in the plan view of FIG. 4, the distance between the central axis Ab2 of the second ball screw 72b and the central axis Ac of the index table 2 is shorter than the distance between the chuck rotation axis Aw and the central axis Ac.

(Operation Panel)

The operation panel 100 is a control unit for operating the grinding machine 1. As illustrated in FIG. 3, the operation panel 100 is located to face the vertical side portion 52 as a basic position. Further, as indicated by the phantom lines in FIG. 3, the operation panel 100 is configured to be movable among a first operation position Px1 facing a user U located at a first chamfer 10a to be described later, a second operation position Px2 facing a user U located at a second chamfer 10b to be also described later, and the basic position Px3 facing an operation surface 10c.

(Other Configurations)

As described above, the bed 3 and the column base 4 form the pedestal 10 that supports the index table 2. The pedestal 10 includes, in the plan view of FIG. 3, the first chamfer 10a cut along the first attachment line L1, the second chamfer 10b cut along the second attachment line L2, and the operation surface 10c located between the first chamfer 10a and the second chamfer 10b and extending along the lateral side portion 51.

(Specific Example of Grinding Step)

In grinding using a grinding machine 1, first, a first wafer is mounted on the chuck 21 located at the replacement position P3. The first wafer is vacuumed and held by the chuck 21.

Subsequently, the index table 2 rotates clockwise by 120° to place the chuck 21 and the first wafer at the rough grinding position P1.

Subsequently, the first spindle 61 of the first grinding mechanism 6 cuts into the first wafer, and rough grinding is performed. At the same time, a second wafer is mounted on another chuck 21 located at the replacement position P3, and is vacuumed and held by the chuck 21. On completion of the rough grinding, the index table 2 rotates clockwise by 120° to move the first wafer and the chuck 21 to the fine grinding position P2 and move the second wafer and the chuck 21 to the rough grinding position P1.

Subsequently, the second spindle 71 of the second grinding mechanism 7 cuts into the first wafer, and fine grinding is performed. At the same time, the first spindle 61 of the first grinding mechanism 6 cuts into the second wafer, and rough grinding is performed. At the same time, a third wafer is mounted on still another chuck 21 located at the replacement position P3, and is vacuumed and held by the chuck 21.

On completion of machining the first and second wafers, the index table 2 rotates counterclockwise (opposite direction) by 240° to move the first wafer and the first chuck 21 to the replacement position P3 and move the second wafer and the second chuck 21 to the fine grinding position P2. The third wafer and the third chuck 21 move to the rough grinding position P1.

Thereafter, the second spindle 71 of the second grinding mechanism 7 cuts into the second wafer, and fine grinding is performed. At the same time, the first spindle 61 of the first grinding mechanism 6 cuts into the third wafer, and rough grinding is performed. At the same time, the first wafer is removed from the first chuck 21 located at the replacement position P3, and a fourth wafer is mounted on that chuck 21 and is vacuumed and held by the chuck 21.

As illustrated in (a) of FIG. 7, if operations such as maintenance need to be performed on the first grinding mechanism 6, the user U moves to the first chamfer 10a to face the first grinding mechanism 6 and at the same time operates, as needed, the operation panel 100 positioned arranged at the first operation position Px1.

Similarly, as illustrated in (b) of FIG. 7, if operations such as maintenance need to be performed on the second grinding mechanism 7, the user U moves to the second chamfer 10b to face the second grinding mechanism 7 and at the same time operates, as needed, the operation panel 100 positioned at the second operation position Px2.

(Summary)

As described above, according to the above embodiment, the first and second grinding mechanisms 6 and 7 are arranged like a bridge between the lateral side portion 51 and the vertical side portion 52. Taking the direction of extension of the vertical side portion 52 into account, it is not that the first and second grinding mechanisms 6 and 7 are arranged side by side along the lateral side portion 51 but that they are arranged obliquely with respect to the extension direction of the lateral side portion 51. This is exemplified in FIG. 5A and FIG. 5B as well.

The oblique arrangement of the first and second grinding mechanisms 6 and 7 allows the lateral side portion 51 to be shorter than the side-by-side arrangement of the first and second grinding mechanisms 6 and 7. It is thus possible to make the column 5 more compact, reduce the pitch between the chucks 21, and in turn make the index table 21 more compact, even if high power motors are used as the drive motors 61d and 71d of the spindles 61 and 71.

The index table 2 made more compact contributes to improvement in the table rigidity. The improvement in the table rigidity is advantageous in grinding a wafer using the high power drive motors 61d and 71d. In addition, the reduction in the size of each of the column 5 and the index table 2 contributes to ensuring machining accuracy.

Furthermore, as exemplified in FIG. 5B, the column 5 is supported at at least three points: both ends 51a and 51b of the lateral side portion 51 and the end 52a of the vertical side portion 52. Thus, even if a large and heavy drive motor 61d is suspended on the column 5, it is possible to reduce distortion and collapse of the column 5.

Furthermore, as exemplified in FIG. 5B, etc., the first and second feeding mechanisms 62 and 72 configured to move the first and second spindles 61 and 71 are located at the first and second corners 53 and 54 at which the lateral side portion 51 and the vertical side portion 52 intersect. By arranging the first and second feeding mechanisms 62 and 72 in this manner, it is possible to arrange the first and second feeding mechanisms 62 and 72 near the center of gravity of the column 5.

Thus, even if distortion occurs in the column 5, it is possible to reduce the collapse of the column 5 due to the distortion. As a result, it is possible to ensure the machining accuracy as described above and reduce the collapse of the column 5 even if the high power drive motors 61d and 71d are used.

As exemplified in FIG. 5B, by arranging the feeding mechanisms 62 and 72 inside the right isosceles triangle T, it is possible to make the feeding mechanisms 62 and 72 closer to the center of gravity of the column 5 as compared to the configuration in which the feeding mechanisms 62 and 72 are located outside the right isosceles triangle T. This configuration is further advantageous in reducing the collapse of the column 5.

Further, by positioning the first spindle 61 at the central portion of the first attachment line L1 and the second spindle 71 at the central portion of the second attachment line L2, it is possible to distribute the load, applied to the column 5 by the spindles 61 and 71, between the lateral side portion 51 and the vertical side portion 52 in a balanced manner. The spindles 61 and 71 can thus be supported stably.

As exemplified in FIG. 5B, etc., the first spindle 61 and the first and second linear guides 81 and 82 are arranged on the same straight line in plan view, and the second spindle 71 and the third and fourth linear guides 91 and 92 are arranged on the same straight line in plan view. It is thus possible to reduce the collapse of the spindles 61 and 71 due to their own weight.

There are concerns that the column 5 increases in size if the spindle 61, 71 and the pair of linear guides 8, 9 are arranged on the same straight line in the plan view. However, such an increase in size can be reduced as much as possible by arranging the first and second grinding mechanisms 6 and 7 obliquely as in this embodiment.

As exemplified in FIG. 3, a space located in front of the first chamfer 10a can be used for maintenance of the first grinding mechanism 6. A space located in front of the second chamfer 10b can be used for maintenance of the second grinding mechanism 7. It is possible to keep the spaces larger by the oblique arrangement of the first grinding mechanism 6 and the second grinding mechanism 7.

This configuration results in the oblique extension of the first chamfer 10a and the second chamfer 10b, which makes it possible to ensure the operation surface 10c between the first chamfer 10a and the second chamfer 10b. A space located in front of the operation surface 10c can be used, for example, as an installation space for the operation panel 100. The usability of the grinding machine 1 is therefore improved.

A wafer is usually attached to and detached from the chuck 21 that has moved to the replacement position P3, by a robot arm or any other component. The vertical side portion 52 is therefore extended in a direction away from the replacement position P3, as exemplified in FIG. 4, to make it possible to reduce the interference between the vertical side portion 52 and the robot arm during the attachment and detachment of the wafer. The usability of the grinding machine 1 is therefore improved.

FIG. 8 shows a variation of the vertical type surface grinding machine 1, and corresponds to FIG. 3. The elements denoted by reference numeral “10xx” in FIG. 8 have the same configurations and functions as the elements denoted by reference numeral “xx” in FIGS. 1 to 7 unless otherwise specified.

The above embodiment is an example of the vertical surface grinding machine 1 including three chucks 21 and two grinding mechanisms 6 and 7. However, as illustrated in FIG. 8, the present disclosure also includes a vertical surface grinding machine 1001 including four chucks 1021 and three grinding mechanisms 1006, 1007, and 1011.

A grinding machine 1001 according to the variation includes four chucks 1021 arranged at intervals of 90° in the circumferential direction. One of the four chucks 1021 (one on the lower left of the sheet of the drawing) is used for wafer replacement as described in the above embodiment. The other three chucks 1021 are arranged so as to be associated with the three grinding mechanisms 1006, 1007, and 1011.

Similarly to the column 5 of the above embodiment, a column 1005 according to the variation includes a lateral side portion 1051 extending in a direction of arrangement of a first grinding mechanism 1006 and a second grinding mechanism 1007, and a vertical side portion 1052 extending perpendicularly from a central portion of the lateral side portion 1051. The column 1005 according to the variation has a cross shape in the plan view.

The three grinding mechanisms 1006, 1007, and 1011 are arranged at intervals of 90° in the circumferential direction, and are arranged in the order of the first grinding mechanism 1006, the second grinding mechanism 1007, and the third grinding mechanism 1011 along the circumferential direction.

The three grinding mechanisms 1006, 1007, and 1011 include spindles 1061, 1071, and 1111 and feeding mechanisms 1062, 1072, and 1112, respectively.

First, in this variation, the first grinding mechanism 1006 has a configuration similar to that of the first grinding mechanism 6 of the above embodiment, and the second grinding mechanism 1007 has a configuration similar to that of the second grinding mechanism 7 of the above embodiment.

That is, the two grinding mechanisms 1006 and 1007 are supported by the lateral side portion 1051 and the vertical side portion 1052 while arranged like a bridge between the lateral side portion 1051 and an upper half portion on the sheet of the drawing of the vertical side portion 1052.

The spindles 1061 and 1071 of the two grinding mechanisms 1006 and 1007 are supported from both sides by the first guide pair 1008 and the second guide pair 1009. The spindles 1061 and 1071 are arranged along the hypotenuse of a triangle connecting both ends of the lateral side portion 1051 on the sheet of the drawing and the upper end of the vertical side portion 1052 on the sheet of the drawing.

The feeding mechanisms 1062 and 1072 of the two grinding mechanisms 1006 and 1007 are located at corners at which the lateral side portion 1051 and the vertical side portion 1052 intersect. The two feeding mechanisms 1062 and 1072 are arranged inside the triangle.

The same applies to the case in which the second grinding mechanism 1007 is assumed to be the first grinding mechanism 6 of the above embodiment and the third grinding mechanism 1011 is assumed to be the second grinding mechanism 7 of the above embodiment.

That is, the two grinding mechanisms 1007 and 1011 are supported by the lateral side portion 1051 and the vertical side portion 1052 while arranged like a bridge between the vertical side portion 1052 and a right half portion on the sheet of the drawing of the lateral side portion 1051.

The spindles 1071 and 1111 of the two grinding mechanisms 1007 and 1011 are supported from both sides by the second guide pair 1009 and the third guide pair 1012. The spindles 1071 and 1111 are arranged along the hypotenuse of a triangle connecting the right end of the lateral side portion 1051 on the sheet of the drawing and both ends of the vertical side portion 1052 on the sheet of the drawing.

The feeding mechanisms 1072 and 1112 of the two grinding mechanisms 1007 and 1011 are located at corners at which the lateral side portion 1051 and the vertical side portion 1052 intersect. The two feeding mechanisms 1072 and 1112 are arranged inside the triangle.

These configurations can also provide similar effects and advantages to those of the above embodiment. That is, according to the grinding machine 1001 according to the variation, it is possible to achieve both of higher power of a drive motor of each of the spindles 1061, 1071, and 1111 and more compact column 1005 and index table 1002.

Other Embodiments

In the above embodiment, a wafer for a semiconductor is exemplified as a workpiece. However, an object to be machined by the grinding machine 1 is not limited to the wafer for a semiconductor. The workpiece may be, for example, a metal part.

In the above embodiment, the first grinding mechanism 6 is exemplified as the first grinding wheel mechanism, and the second grinding mechanism 7 is exemplified as the second grinding wheel mechanism. However, the present disclosure is not limited to such a configuration. The first and second grinding wheel mechanisms are not limited as long as they carry out machining using a grinding wheel. For example, a grinding mechanism for performing fine grinding similar to the fine grinding of the above embodiment may be used as the first grinding wheel mechanism, and at the same time, a polishing mechanism for polishing a workpiece may be used as the second grinding wheel mechanism. Furthermore, the first grinding wheel mechanism and the second grinding wheel mechanism may perform the same type of machining, such as rough grinding of the workpiece. That is, the first and second grinding wheel mechanisms are not limited to mechanisms for performing grinding and may be any general mechanisms with a grinding wheel.

Alternatively, the vertical type surface grinding machine 1 may be a multitasking machine that performs a combination of external grinding, internal grinding, and end grinding.

In the above embodiment, the chucks 21 are configured to vacuum and hold the workpiece (the wafer). However, the present disclosure is not limited to such a configuration. For example, the chucks 21 may be electrostatic chucks, magnet chucks, or claw chucks.

DESCRIPTION OF REFERENCE CHARACTERS

1 Grinding Machine (Vertical Type Surface Grinding Machine)

2 Index Table

21 Chuck

3 Bed

4 Column Base

41 First Supporting Portion

42 Second Supporting Portion

43 Third Supporting Portion

5 Column

51 Lateral Side Portion

51
a First End

51
b Second End

52 Vertical Side Portion

52
a Third End

53 First Corner (Corner)

54 Second Corner (Corner)

6 First Grinding Mechanism (First Grinding Wheel Mechanism)

61 First Spindle (Spindle)

62 First Feeding Mechanism (Feeding Mechanism)

7 Second Grinding Mechanism (Second Grinding Wheel Mechanism)

71 Second Spindle (Spindle)

72 Second Feeding Mechanism (Feeding Mechanism)

8 First Guide Pair (Pair of Linear Guides)

81 First Linear Guide (One of Linear Guides)

82 Second Linear Guide (The Other Linear Guide)

9 Second Guide Pair (Pair of Linear Guides)

91 Third Linear Guide (One of Linear Guides)

92 Fourth Linear Guide (The Other Linear Guide)

10 Pedestal

10
a First Chamfer

10
b Second Chamfer

Ac Central Axis

As1 First Rotation Axis (Rotation Axis of Spindle)

As2 Second Rotation Axis (Rotation Axis of Spindle)

L1 First Attachment Line (Straight Line Connecting First Supporting Portion and Third Supporting Portion Together)

L2 Second Attachment Line (Straight Line Connecting Second Supporting Portion and Third Supporting Portion Together)

P1 Rough Grinding Position (First Position)

P2 Fine Grinding Position (Second Position)

P3 Replacement Position (Third Position)

Px1 First Operation Position

Px2 Second Operation Position

100 Operation Panel

VERTICAL TYPE SURFACE GRINDING MACHINE

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

International Classifications

Abstract

Description

Claims

Priority Claims (1)