JPH11320424A - Grinding wheel for polishing substrate and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinding wheel for polishing a substrate to ensure high polishing efficiency and eliminate a risk of the grinding wheel being collapsed and to provide a polishing device. SOLUTION: A grinding wheel 10 is constituted such that the periphery of a pellet-shaped first grinding wheel member 21 is covered with a second grinding wheel member 25 in a cylindrical shape. The second grinding wheel member 25 is formed of a material further hardly shaved off than the first grinding wheel member 21. Instead of the second grinding wheel member 25, a rigid material being not the grinding wheel may be used. This constitution causes the passage of abrasive grains shaven off from the first grinding wheel member 21 through a gap between the second grinding wheel member 25 and a substrate to be polished when the first and second grinding wheel members 21 and 25 effect a relative motion with the members brought into simultaneous contact with the substrate to be polished.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing wheel and a polishing apparatus suitable for use as a polishing tool for polishing a substrate to be polished such as a semiconductor wafer, various hard disks, a glass substrate and a liquid crystal panel.

[0002]

2. Description of the Related Art Conventionally, in a manufacturing process of a semiconductor integrated circuit device, a process of flattening the surface of a substrate to be polished such as a semiconductor wafer using a CMP (chemical mechanical polishing) device is indispensable. The CMP apparatus abuts a substrate to be polished mounted on a rotating top ring on a polishing cloth surface stuck on a turntable, and supplies a polishing slurry onto the polishing cloth, The polishing surface is polished (free abrasive polishing).

However, in the case of this CMP apparatus, there is a problem that it cannot be sufficiently flattened depending on the type of the pattern on the polished surface of the substrate to be polished and the state of the steps (irregularities), and the consumption of expensive high-purity polishing slurry for semiconductors. There was a problem that the amount was large.

On the other hand, instead of the CMP apparatus having the above structure, a grinding wheel for polishing the substrate is pressed against the substrate to be polished, and both are relatively moved while supplying an abrasive liquid (solution) to the surface of the grinding stone, thereby polishing the substrate to be polished. A fixed abrasive polishing method has been developed.

According to this method, as compared with the CMP apparatus using the polishing cloth, not only can the flattening function be improved, but also it is not necessary to use a large amount of expensive polishing slurry, so that the running cost can be reduced. Can also be planned.

FIG. 6 is a basic operation explanatory view showing a polishing method using a pellet type grindstone in the fixed abrasive grain polishing method.

As shown in FIG. 1, the grinding method using a pellet-type grindstone is such that a plurality of (eight) pellet-type grindstones 80 are attached to the lower surface of a disk-shaped grindstone support member 85 in a ring shape.
By pressing the surface of the grindstone 80 against the surface of the semiconductor wafer 100 and rotating both in the directions of arrows D and E, and simultaneously moving the grindstone support plate 85 linearly in the direction of arrow F, the surface of each grindstone 80 is The surface of the semiconductor wafer 100 is polished by rubbing against the surface of the semiconductor wafer 100.

[0008]

However, the conventional fixed abrasive polishing method has the following problems.

In other words, in the fixed abrasive polishing method, abrasive grains are polished from the surface of the grindstone itself by rubbing a grindstone on the substrate to be polished, and the substrate to be polished is polished by the cut abrasive grains. It is preferable to use a whetstone that is easily worn since a large amount of abrasive grains are cut out from the whetstone and the polishing rate of the non-polished substrate can be increased.

[0010] However, in the case of a whetstone that is easily worn, depending on the pressing pressure, frictional force, and the effect of the abrasive fluid used,
There was a risk that the whetstone would easily collapse.

On the other hand, in order to avoid this, if the grindstone is hardly worn to some extent, the pressing force and the frictional force can be increased, but the abrasive grains are less likely to be removed from the grindstone, and the polishing efficiency is deteriorated.

The present invention has been made in view of the above points, and an object of the present invention is to provide a grinding wheel and a polishing apparatus for polishing a substrate, which can ensure high polishing efficiency and are not likely to collapse.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a grinding wheel for polishing a substrate to be polished by bringing the substrate to be polished into contact with the surface thereof and moving relative to each other. A first whetstone member; the first whetstone member;
A second whetstone member or a hard material that cannot be cut by the whetstone member, and the first whetstone member and the second whetstone member or the hard material are simultaneously brought into contact with the substrate to be polished and relatively moved. At this time, the structure was such that abrasive grains shaved from the first grindstone member passed between the second grindstone member or the hard material and the substrate to be polished.
In addition, the present invention uses a pellet-type grindstone arranged in a ring shape as the substrate polishing grindstone, and forms the grindstone around a pellet-shaped first grindstone member with a cylindrical second grindstone member or a hard grindstone. It was configured to be covered with a material. The present invention also provides
A ring-shaped grindstone was used as the substrate polishing grindstone, and the grindstone was configured to cover the inside and outside of the ring-shaped first grindstone member with a ring-shaped second grindstone member or a hard material. Also, the present invention provides a method in which the first whetstone member is pressed toward a polishing surface by a pressing means, or the second whetstone member or a hard material is pressed toward a polishing surface by a pressing means, or The structure was such that the first grindstone member and the second grindstone member or the hard material were pressed toward the polishing surface by separate pressing means. Further, the present invention provides the above-mentioned substrate polishing grindstone, a grindstone supporting member for holding the substrate polishing grindstone, a substrate to be polished in contact with the surface of the substrate polishing grindstone, and a grinding stone supporting member. The polishing apparatus was provided with a drive mechanism that rubs the substrate to be polished against a grindstone by causing the polishing substrate to move relative to each other.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing a state in which a grindstone 10 according to an embodiment of the present invention is attached to a grindstone support member 30. FIG. 1A is a side sectional view (A in FIG. 1B).
-A sectional view), FIG. 4B is a rear view, and FIG. 4C is an enlarged sectional view of one grindstone 10. As shown in the figure, eight grindstones 10 are fixed in a ring shape on the back surface of a disc-shaped grindstone support plate 30, and the grindstone 10 is placed in a cup-shaped grindstone holder 11 by a first grindstone member. 21, a second grindstone member 25 and a coil spring (pressing means) 29 are housed. Hereinafter, each component will be described.

The first grindstone member 21 is formed in a cylindrical shape. The second grindstone member 25 has a cylindrical shape,
The inner circumference covers the outer circumference of the first grindstone member 21, and the outer circumference is formed in such a size as to be fitted and fixed to the inner circumference surface of the grindstone holder 11. On the other hand, the coil spring 29 has one end fixed to the upper end surface of the grindstone holder 11 and the other end fixed to the upper surface of the first grindstone member 21.

That is, the first grindstone member 21 is vertically movable with respect to the second grindstone member 25 so that the coil spring 29 is movable.
Is held by the grindstone holder 11. At this time, the lower surface of the first grindstone member 21 and the lower surface of the second grindstone member 25 are shown as being the same in the drawing, but this shows a state when the member to be polished is polished. When no other member is in contact with the lower surface, the lower surface of the first grindstone member 21 projects downward from the lower surface of the second grindstone member 25. In other words, the first and second grinding stone members 2
The first and second grindstone members 21 are configured to apply a predetermined pressurizing pressure when the lower surfaces of the first and the 25th surfaces become the same surface.

Here, the first grindstone member 21 is made of a material which is easily worn and has a high polishing efficiency (the polishing rate of the substrate to be polished is high), while the second grindstone member 25 is hardly worn and the first grindstone member 25 is made of the first material. Is made of a material that cannot be cut more than the grindstone member 21.

That is, for example, the first and second grindstone members 21,
25 is to vary the abrasive particle size, abrasive material, binder type, grinding wheel porosity, firing temperature, firing time, etc.
The first grindstone member 21 is configured to be easily worn, and the second grindstone member 25 is configured to be hardly worn.

Specifically, silica particles (average primary particle radius of about 30 nm) are used as abrasive grains, and liquid phenol resin (viscosity: 0.2 P / 25 ° C., non-volatile components: 48%, methanol solvent) is used as a binder. 170 ° C firing temperature
/ 2 hr is the same, but by manufacturing the two with a whetstone porosity of 72% and 48%, the higher whetstone porosity is used as the first whetstone member 21, The lower one was used as the second grindstone member 25.

In other words, "not shave" means that it is difficult to grow or wear, or that the content of the bonding material is small, and "easy to cut" means that it is easy to grow or It means that it is easily worn or that the content ratio of the bond material is large. In addition, the term “self-generated” as used herein means that when a mechanical action and / or a chemical action or a thermal action is applied to a grindstone member, the grindstone is fixed to a grinding surface by a binder. Abrasive "
Is removed from the surface of the grinding wheel or the substrate to be polished together with the binder, causing the "new abrasive grains with high polishing ability contained in the grinding wheel" to appear on the grinding surface, and further releasing the new abrasive grains from the grinding wheel. , A phenomenon including a contribution to polishing. Here, the polishing ability refers to polishing speed, polishing accuracy, and the like, and the binder refers to phenol resin and the like.

Next, the operation of the grindstone 10 will be described. That is, as shown in FIG. 2, when this grindstone 10 is brought into contact with the surface of the substrate 100 to be polished such as a semiconductor wafer and is relatively moved with each other as shown by arrows, the first and second grindstone members 2 are formed.
Each of the contact surfaces 1 and 25 with the substrate to be polished 100 is rubbed against the surface of the substrate to be polished 100, and the respective contact surfaces are shaved to polish the substrate to be polished 100.

At this time, the first grindstone member 21 is shaved more than the second grindstone member 25, and
Although the abrasive grains contributed to the polishing of the first grinding stone member 21 and the first grinding stone member 21
Not only is it used for polishing at the contact surface with 0,
It is also used for polishing when passing through the contact surface between the second grindstone member 25 and the substrate 100 to be polished. In other words, the first grindstone member 21 located on the inner side cuts out and grinds sufficient abrasive grains, and the second grindstone member is harder to wear than the pressurized abrasive grains located on the outer periphery. 25, the flattening polishing of the substrate to be polished 100 progresses,
The high step characteristics of the substrate to be polished 100 can be improved.

Particularly in the case of the present embodiment, the first grindstone member 2
1 is covered by the second grindstone member 25, the first
All the abrasive grains cut out by the whetstone member 21 always pass between the second whetstone member 25 and the substrate to be polished 100 and are discharged, so that efficient polishing can be performed.

In some cases, the first grindstone member 21 is easily worn and cannot be sufficiently pressurized, so polishing may not proceed. In such a case, the second grindstone member is hardly worn and can be sufficiently pressurized. Sufficient polishing efficiency can be obtained by passing the abrasive grains cut by the first grindstone member 21 between the member 25 and the member 100 to be polished.

On the other hand, the first grindstone member 21 has good polishing efficiency, but may be easily collapsed by the influence of the pressing pressure, the frictional force, the abrasive fluid used and the like. However, in the present embodiment, the second grindstone member 25, which is hard to wear, covers the periphery of the first grindstone member 21, so that the first grindstone member 21 does not collapse.

That is, in the present embodiment, the disadvantages of both the whetstone that is easily worn and the whetstone that is hard to wear are eliminated, and only the advantages of both are brought out.

When the substrate to be polished 100 is polished,
The first grindstone member 21 wears faster than the second grindstone member 25. However, according to the present embodiment, the coil spring 29 is reduced by the amount that the first grindstone member 21 is more worn.
Extruded by Therefore, the first and second grinding stone members 2
In both 1 and 25, the polishing of the substrate to be polished 100 can be continued at a predetermined pressure.

FIG. 3 is a schematic perspective view showing a polishing apparatus constituted by using the grindstone 10 and the grindstone support plate 30 shown in FIG. As shown in the figure, a rotating shaft 31 attached to the center of the upper surface of the grindstone support plate 30 is attached to an arm 201 of a polishing apparatus 200 having a built-in driving mechanism for rotating the rotating shaft 31.

On the other hand, the disc-shaped semiconductor wafer 100 is held on a substrate holder 211.

The substrate holder 211 and the semiconductor wafer 100
Is installed to be exposed in the table 213,
The upper surfaces of the substrate holder 211 and the semiconductor wafer 100 and the upper surface of the table 213 are configured to be flush with each other.

The table 213 and the substrate holder 211 are configured to be movable in a linear direction (the direction of arrow J) by a drive mechanism (not shown) on the base 203 of the polishing apparatus 200.

Then, the substrate holder 211 and the grindstone support plate 30
And the semiconductor wafer 100 are independently rotated.
If the grindstone 10 is pressed against the wafer and the table 213 is moved linearly at the same time, the entire surface of the semiconductor wafer 100 is polished. At that time, as described above, the semiconductor wafer 100 is efficiently polished by the grindstone 10 according to the present invention.

FIGS. 4A to 4D are enlarged sectional views showing another embodiment of the pellet type grinding wheel. That is,
In the present invention, as shown in FIG. 4 (a), in addition to the first whetstone member 21 being repelled by the coil spring 29, the second whetstone member 25 is also separately downwardly (polished) by a coil spring (pressing means) 28. Grindstone holder 11
4B, the second grindstone member 25 is formed in a cup shape, and the first grindstone member 21 is inserted therein via a coil spring 29, as shown in FIG. It may be stored up and down freely, and FIG. 4 (c)
As shown in (1), the first grindstone member 21 may be fixed to the grindstone holder 11, and only the second grindstone member 25 may be vertically movably mounted on the grindstone holder 11 by the coil spring 28 so as to be resiliently moved downward. Even with such a configuration, the same operation and effect as those of the grindstone 10 shown in FIG. 1 are produced.

Also, in the present invention, as shown in FIG. 4D, the first cylindrical member is opposite to the embodiment shown in FIG.
The coil spring 29 is vertically movable inside the grindstone member 21 '.
May be configured to house the cylindrical second grindstone member 25 'held by the above. Here, the first grindstone member 21 'is made of a material that is more easily worn than the second grindstone member 25', as in the above-described embodiment.

In the case of such a configuration, the first abrasion-resistant first
Although the effect of preventing the grinding wheel member 21 'from collapsing does not occur, the abrasive grains cut by the first grinding wheel member 21' are guided to the polishing surface of the second grinding wheel member 25 'to improve the polishing efficiency. The effect of contributing to is produced.

FIG. 5 is a view showing an embodiment in which the present invention is applied to a ring-type grindstone. FIG. 5 (a) is a side sectional view (BB sectional view of FIG. 5 (b)), and FIG. (b) is a back view.

The grindstone 50 in the embodiment shown in the figure is a ring-shaped grindstone. Specifically, two ring-shaped second grindstones 55-having different diameters are provided on the back surface of a disc-shaped grindstone support plate 60. 1, 55-2 are concentrically fixed, and a ring-shaped first grindstone 51 is attached between the two so as to be vertically movable via a coil spring (pressing means) 69.
In other words, the inside and the outside of the first grindstone member 51
Are configured to be covered by the grindstone members 55-1 and 55-2.

It goes without saying that the same effect as in the case of the grindstone 10 shown in FIG. Also in this embodiment, it is needless to say that the structures of the first and second grindstone members 51, 55-1, and 55-2 can be variously modified as shown in FIG.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to these embodiments, and for example, the following various modifications are possible.

In each of the above embodiments, the second grindstone member is constituted by a grindstone which cannot be cut more than the first grindstone member.
The second grindstone member may be replaced with a hard material other than a grindstone, for example, made of a hard resin or the like. Here, as a hard material, compared with a soft member, a solution that does not collapse due to a pressing force or the like, and is a member that efficiently transmits pressure to a polishing surface when pressed through a grindstone support member, polycarbonate, PVC, or Ceramics such as alumina can be used. Even with such a configuration, a polishing effect is generated when the abrasive grains cut by the first grindstone member pass between the hard material and the substrate to be polished.

The arrangement structure of the first and second grindstone members can be further modified in various ways. In short, the first and second grindstone members (or hard materials) are simultaneously polished. The abrasive grains cut out from the first grindstone member when abutting on the substrate and making relative movement are used as the second grindstone member (or hard material).
Any structure may be used as long as the structure allows passage between the substrate and the substrate to be polished.

In each of the above embodiments, a coil spring is used as the pressurizing means. However, another kind of pressurizing means, for example, a spring having another structure, pressurized air, pressurized liquid, or pressure by screw torque may be used. .

It goes without saying that various modifications can be made to the shape and structure of each member such as the grindstone support plate.

The structure of the polishing apparatus can be variously modified. The point is that the grinding wheel for substrate polishing, the grinding wheel support member holding the grinding stone, the substrate to be polished in contact with the surface of the grinding stone, and the relative movement between the grinding wheel support member and the substrate to be polished are made to move relative to each other. A polishing apparatus having any structure may be used as long as the polishing apparatus includes a driving mechanism for polishing a substrate to be polished by grinding the substrate against a grindstone.

In some cases, together with the polishing apparatus according to the present invention, a CMP apparatus comprising a polishing cloth or the like described in the section of the prior art is installed, and the CMP apparatus is used before and after polishing by the polishing apparatus according to the present invention. The apparatus to be polished may be polished by a CMP apparatus.

[0046]

As described in detail above, the present invention has the following excellent effects. Since the abrasive grains cut from the first grindstone member are configured to pass between the second grindstone member or the hard material and the substrate to be polished, sufficient abrasive grains are cut from the first grindstone member. Can be polished, and can be ground less than the first whetstone member.
The flattening and polishing of the substrate to be polished can be effectively performed by the grinding stone member or the hard material. In particular, when the first grindstone member is covered with the second grindstone member (or hard material), all the abrasive grains cut out by the first grindstone member are necessarily covered with the second grindstone member (or hard material). This is effective because it is discharged after passing between the polishing substrates.

When the first grindstone member is configured to be covered with the second grindstone member or a hard material, the first whetstone member which is easily worn is used.
Can be prevented from collapsing, and a grindstone member that is more easily worn and has a high polishing rate can be used as the first grindstone member.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a grindstone 10 according to an embodiment of the present invention is attached to a grindstone support member 30, and FIG. 1A is a side sectional view (AA sectional view of FIG. 1B). FIG. 2B is a rear view, and FIG. 1C is an enlarged sectional view of one grindstone 10.

FIG. 2 is an explanatory diagram of an operation of the grindstone 10;

FIG. 3 is a schematic perspective view illustrating an example of a polishing apparatus configured using a grindstone 10.

FIGS. 4A to 4D are enlarged cross-sectional views showing another embodiment of a pellet-type grindstone.

FIG. 5 is a view showing an embodiment in which the present invention is applied to a ring-type grindstone; FIG. 5A is a side sectional view (B in FIG.
-B cross-sectional view), and FIG.

FIG. 6 is a basic operation explanatory view showing a polishing method using a pellet-type grindstone in the fixed abrasive grain polishing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Whetstone 11 Whetstone holder 21 First whetstone member 25 Second whetstone member 28 Coil spring (pressing means) 29 Coil spring (pressing means) 30 Whetstone supporting member 69 Coil spring (pressing means) 100 Substrate to be polished

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Naosuke Matsuo 4-2-1 Motofujisawa, Fujisawa-shi, Kanagawa Inside Ebara Research Institute Co., Ltd.

Claims (5)

[Claims] 1. A grinding wheel for polishing a substrate to be polished by bringing the substrate to be polished into contact with the surface thereof and causing them to move relative to each other, wherein the grinding wheel comprises: a first grinding wheel member; When a second grindstone member or a hard material is provided, which is harder than a grindstone member, and the first grindstone member and the second grindstone member or the hard material are simultaneously brought into contact with a substrate to be polished and relatively moved. A grinding wheel for polishing a substrate, wherein abrasive grains shaved from the first grinding wheel member are configured to pass between the second grinding wheel member or the hard material and the substrate to be polished. 2. The grinding wheel for polishing a substrate is a pellet-shaped grinding wheel arranged in a ring shape, and the grinding wheel is formed around a first grinding wheel member having a pellet shape and a second grinding wheel member having a cylindrical shape or a hard grinding wheel. The grinding wheel for polishing a substrate according to claim 1, wherein the grinding wheel is configured to be covered with a material. 3. The substrate polishing grindstone is a ring-shaped grindstone, and the grindstone covers the inside and outside of a ring-shaped first grindstone member with a ring-shaped second grindstone member or a hard material. The grinding wheel for polishing a substrate according to claim 1, wherein the grinding wheel is configured as follows. 4. The method according to claim 1, wherein the first grindstone member is pressed toward the polishing surface by pressing means, or the second grindstone member or a hard material is pressed toward the polishing surface by pressing means.
4. The substrate according to claim 1, wherein the first whetstone member and the second whetstone member or the hard material are configured to be pressed toward the polishing surface by separate pressing means. 5. Polishing whetstone. 5. A grinding wheel for polishing a substrate according to claim 1, 2, 3 or 4, a grinding wheel support member for holding the grinding wheel for substrate polishing, and a substrate to be polished by contacting the surface of the grinding wheel for substrate polishing. A polishing apparatus, comprising: a polishing substrate; and a drive mechanism for polishing the substrate to be polished by rubbing the substrate against a substrate polishing grindstone by relatively moving the grindstone support member and the substrate to be polished relative to each other. .