JPH10551A - Chemical machine polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To polish a polished surface of a workpiece at high speed, in high precision and uniformly by simultaneously applying uniform pressure on all polishing pads by using a plural number of polishing heads. SOLUTION: Each of a plural number of polishing heads 10, 10 respectively has an elastic thin film 21 forming a pressure fluid chamber 20 by receiving pressure fluid of water, air, etc., and holds a polishing pad 15 on the side of a lower surface of this elastic thin film 21. Each of the pressure fluid chambers 20 is communicated to each other through a solid chamber 22 having capacity larger than the pressure fluid chamber 20. A polishing surface of each of the polishing pads 15 is automatically equalized, equally distributed pressure is applied, the same pressure is simultaneously applied on all of the polishing pads 15, the polishing surfaces of a plural number of the polishing pads 15 polish a workpiece at uniform working pressure and flatten it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical mechanical polishing apparatus for polishing a substrate such as a wafer with high precision.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have become ultra-miniaturized and highly stepped, and with this, quartz, in which a plurality of island-shaped semiconductor regions are formed on a semiconductor wafer such as Si, GaAs, InP, or the like, or the like, has It is required to flatten the surface of a substrate such as a glass substrate with high precision. As processing means for flattening the surface of a substrate such as a wafer with high precision,
A chemical mechanical polishing (CMP) apparatus as described below is known.

As shown in FIG. 3, this conventional chemical mechanical polishing apparatus includes a workpiece holder 103 for detachably holding a substrate 104 such as a wafer on a lower surface, and a workpiece holder 103.
A polishing tool turntable 101 on which a polishing pad 102 having a larger diameter than the diameter of a substrate 104 disposed opposite to and disposed integrally is mounted, and an abrasive (polishing slurry) 107 on the polishing pad 102 A workpiece supply body 103 holding a substrate 104 is provided with a polishing agent supply nozzle 106 for supplying a polishing pad 102, and a polishing tool turntable 101 on which a polishing pad 102 is integrally attached is rotated as shown by an arrow A. In the state where a processing pressure is applied to the rotating shaft 105 in the axial direction to press the substrate 104 against the polishing pad 102, the workpiece holder 103 is subjected to a rotational motion indicated by an arrow B and a radial linear motion, and Pad 102 and substrate 1
It is configured to perform chemical mechanical polishing while supplying an abrasive (polishing slurry) between the substrate and the substrate.

[0004] As for the workpiece holder, there is known an Air / Water back type in which the processing pressure over the entire polished surface of the substrate can be made uniform and the polished surface can be polished uniformly. . That is, Ai shown in FIG.
The workpiece holder of the r / Water back system is an elastic body 112 in which a pressure fluid such as air or water is sealed.
And a weight 110 for pressing the elastic body 112 downward.
The elastic body 11 is attached to the substrate 104 which is in contact with the upper surface of the polishing pad 102 mounted on the rotary table 101.
2, the polished surface of the substrate 104 is pressed against the polishing pad 102 by the weight of the weight 110 on the upper surface side of the elastic body 112, and in this state, the rotation and revolution of the workpiece holder, and the rotation of the rotary table 101. Or a linear motion to perform chemical mechanical polishing. The substrate 104 is made of an elastic body 112 sealed with a pressure fluid.
Is pressed to the polishing pad 102 through the substrate, so that the entire surface to be polished of the substrate is uniformly pressed, and even if the degree of parallelism or flatness of the surface to be polished of the substrate is insufficient, a uniform Polishing was possible and planarization was possible.

[0005]

However, in the above-mentioned prior art, the diameter of the polishing tool rotary table on which the polishing pad is integrally mounted is larger than the diameter of the substrate, and the workpiece holder is simple. Therefore, there is an unsolved problem as described below.

(1) The entire polishing apparatus including the rotating table of the polishing tool becomes large. When the rotating table of the polishing tool is rotated at a high speed, vibration is generated and the surface to be polished of the substrate as the workpiece can be polished with high precision. Therefore, the polishing tool rotating table cannot be rotated at a high speed. As a result, the polishing rate (the removal amount per unit time) cannot be increased.

(2) When the surface of the substrate to be polished is polished while the entire surface to be polished is in contact with the polishing surface of the polishing pad, and the substrate to be polished has a local flaw. ,
It is difficult to efficiently remove such local flaws.

(3) In a conventional Air / Waterback type workpiece holder capable of performing uniform polishing by equalizing the processing pressure over the entire surface to be polished of the substrate, which is the workpiece, the individual elasticity The inside of the body is filled with pressure fluid and sealed, and the processing pressure is formed by each independent elastic body, so when using multiple workpiece holders, all the workpiece holders have the same pressure. It was difficult to adjust so as to press.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and is intended to apply a plurality of small-diameter polishing pads to a surface to be polished of a workpiece under uniform pressure. It is an object of the present invention to realize a chemical mechanical polishing apparatus capable of uniformly polishing a surface to be polished of a workpiece with high speed and high accuracy.

[0010]

In order to achieve the above object, a chemical mechanical polishing apparatus according to the present invention provides a polishing pad held by a polishing head by applying a predetermined processing pressure to a surface to be polished of a workpiece. In a chemical mechanical polishing apparatus that performs polishing while supplying an abrasive between the polishing pad and the surface to be polished, an elastic thin film that receives a supply of a pressure fluid to form a pressure fluid chamber is provided. Having a plurality of polishing heads holding a polishing pad on the lower surface side of the elastic thin film,
The pressure fluid chambers are connected to each other via a solid chamber having a larger capacity than the pressure fluid chamber.

Further, the chemical mechanical polishing apparatus of the present invention comprises: a rotary table which removably holds and rotates a workpiece;
A plurality of polishing heads disposed opposite to the rotary table for detachably holding a polishing pad; and a revolving unit for revolving the polishing heads by supporting the plurality of polishing heads rotatably and axially movably. A table, means for rotating the polishing head, and means for moving the polishing head in the axial direction, wherein a polishing pad held by the polishing head is applied with a predetermined processing pressure to a surface to be polished of the workpiece. In a chemical mechanical polishing apparatus that performs abrasion while supplying a polishing agent between the surface to be polished of the workpiece and the polishing pad while being brought into contact with each other in a given state, the polishing heads each include a pressure fluid. An elastic thin film receiving the supply to form a pressure fluid chamber has a polishing pad held on the lower surface side of the elastic thin film, and the pressure fluid chamber has a larger capacity than the pressure fluid chamber. Via a solid chamber to it is characterized in that communicate with each other.

The pressure fluid supplied to the pressure fluid chamber formed by the elastic thin film of the present invention is preferably a gas or a liquid.

Further, in the chemical mechanical polishing apparatus of the present invention, it is preferable that individually adjustable fluid resistors are disposed in respective pipes communicating the pressure fluid chamber and the solid chamber of the plurality of polishing heads.

[0014]

Each of the plurality of polishing heads has an elastic thin film forming a pressure fluid chamber by receiving a supply of a liquid or gas pressure fluid, and is configured to hold a polishing pad on a lower surface side of the elastic thin film. By connecting the pressure fluid chambers to each other through a large-capacity solid chamber, the polishing pad is pressed at a uniform pressure in each polishing head, and the polishing surface of the polishing pad is automatically equalized. In the plurality of polishing heads, the same pressure can be simultaneously applied to all the polishing pads, and the polished surfaces of the plurality of polishing pads can be polished on the polished surfaces of the workpiece with a uniform processing pressure. can do.

[0015] Further, by providing individually adjustable fluid resistors in the respective branch pipes communicating the respective pressure fluid chambers and the solid chamber, the fluctuation and pressure of the pressure fluid in each pressure fluid chamber can be temporarily reduced. The optimum processing pressure can be set according to the polishing surface of the polishing pad and the condition of the workpiece, and finally, the workpiece is polished with a uniform processing pressure and flattened. can do.

[0016]

Embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the chemical mechanical polishing apparatus of the present invention comprises a workpiece holding station which detachably holds a substrate W such as a wafer as a workpiece and rotates and horizontally moves in a radial direction. And a polishing head station for supporting a plurality of polishing heads 10 and 10 disposed above the workpiece holding station to revolve and rotate.

As shown in FIG. 1, the workpiece holding station supports the rotary table 5 on the upper surface of the guide table 3 provided integrally on the base 1 to move the rotary table 5 in the radial direction. A slider 4, a linear drive mechanism (not shown) for moving the slider 4, a rotary table 5 having a rotary shaft 6 rotatably supported by the slider 4 via a bearing, and an illustration for rotating the rotary table 5 A rotation driving mechanism is provided, and the substrate W is detachably held on the upper surface of the turntable 5 to be rotated while being moved in the radial direction.

The polishing head station includes a revolving table 8 rotatably supported via a bearing on a lower yoke 2 a of a support member 2 erected on the base 1, which protrudes above the workpiece holding station, via a bearing. Upper yoke 2b of support member 2
A rotation table rotation drive mechanism 7 for rotating the rotation table 8 at a predetermined rotation speed, and a plurality of polishing heads 10 supported on the rotation table 8 such that the shaft portion 11 is rotatable and movable in the axial direction. A rotating head / linear driving mechanism 12 connected to the upper end side of a shaft portion 11 for rotating the polishing head 10 in the axial direction and moving the polishing head 10 in the axial direction. The rotating drive mechanism and the linear drive mechanism 12 allow the polishing pad 15 to contact the polishing surface of the substrate W by moving the polishing pad 15 at high speed and linearly moving in the axial direction, or to separate the polishing pad 15 from the polishing surface of the substrate W. Can be done. The polishing head 10 can be revolved by rotating the revolving table 8 by the revolving table rotation drive mechanism 7.

The plurality of polishing heads 10 have the same structure. As shown in FIG. 2, a pressure fluid chamber 20 is formed in a cylindrical frame 17 attached to the shaft 11. An elastic thin film 21 is disposed, and the pressure fluid chamber 20 is communicated with a large-capacity solid chamber 22 described later via a branch pipe 24 for supplying pressure fluid.
A gas pressure fluid such as air or liquid such as water is supplied. A polishing pad 15 is attached to the lower surface of the elastic thin film 21 forming the pressure fluid chamber 20 via a polishing pad holding member 16, and the upper surface of the elastic thin film 21 is pressed against the upper surface of the elastic thin film 21. A restraining member 18 for restraining the movement to the side is disposed in the cylindrical frame 17. The restraining member 18 may be a fixed member integrally fixed to the frame 17, or may be a pressure fluid chamber 20.
The elastic thin film 21 to which the pressurized fluid is supplied may be configured as a weight member for pressing the polishing pad downward by pressing the elastic thin film 21 downward.

The elastic thin film 2 disposed on each polishing head 10
Each of the pressure fluid chambers 20 formed by the pressure fluid chambers 20 communicates with a solid chamber 22 having a capacity larger than the pressure fluid chamber 20 via a branch pipe 24 for supplying pressure fluid.
0 are all communicated via the solid chamber 22. The solid chamber 22 is mounted on a base or the revolving table 8 and is connected to a pressure fluid supply source via a main pipe 23.

Thus, the pressure fluid is supplied to the pressure fluid chambers 20 of the plurality of polishing heads 10 and 10 via the solid chamber 22, and the polishing pad 15 attached to the lower surface of the elastic thin film 21 is brought into contact with the substrate W. And the same pressure is simultaneously applied to each elastic thin film 21 forming the pressure fluid chamber 20, and in each polishing head 10,
The polishing pad 15 is pressed with a uniform distribution pressure, and the polishing surface of the polishing pad 15 is automatically equalized. Then, in the plurality of polishing heads 10, 10, the same pressure is simultaneously applied to uniformly press all the polishing pads 15, 15.

Further, since the plurality of pressure fluid chambers 20 formed by the elastic thin film 21 communicate with each other through the solid chamber 22 having a large capacity, any one of the polishing heads 10 is transferred from the polishing surface of the substrate to the polishing head 10. Even if any sudden external force acts, the other polishing heads are not immediately affected, and the polishing can be performed without adversely affecting the polishing.

Further, respective branch pipes 24 between the solid chamber 22 and the pressure fluid chamber 20 of each polishing head,
The provision of individually adjustable fluid resistors at 24 allows temporary adjustment of pressure fluid fluctuations and pressures within the pressure fluid chamber, and the polishing of the polishing pad in multiple polishing pads. An optimum processing pressure can be set according to the height of the surface and the height of the surface to be polished of the substrate W.

Next, the operation of this embodiment will be described.

The substrate W is held on the upper surface of the rotary table 5, and then the slider 4 is moved in the radial direction to position the substrate W at a position where all the polishing heads 10 are brought into contact.

Thereafter, the polishing head 10 is moved axially downward toward the substrate W. At this time, the pressure fluid chamber 2 is lowered by the linear movement driving device 12 and
By supplying the pressure fluid to 0, the polishing pad 15 of the polishing head 10 is brought into contact with the surface to be polished of the substrate W so as to give a predetermined processing pressure.

An abrasive (polishing slurry) not shown
While the polishing agent (polishing slurry) is supplied from the supply means, the polishing head is revolved and rotated at high speed, and at the same time, the rotary table 5 is rotated and moved in a short stroke in the radial direction to perform chemical mechanical polishing.

As described above, the polishing pad 1 of each polishing head
5 is pressurized by elastic thin films 21, 21 forming pressure fluid chambers 20, 20 communicating with each other, the same pressure can be simultaneously applied to a plurality of polishing pads 15, and each polishing head 10 Since the polishing pads 15 are attached to the elastic thin film 21, the polishing surfaces of the respective polishing pads 15 are automatically equalized, and the entire surface of the plurality of polishing pads 15 is brought into contact with the surface to be polished of the substrate W with a uniform pressure. Even if the surface of the substrate W has unevenness in parallelism or flatness, the entire surface of the substrate can be uniformly polished.

The workpieces suitable for polishing by the polishing apparatus of the present invention include Si, Ge, GaAs, and In.
Substrates such as a semiconductor such as P or a quartz or glass substrate having a plurality of island-shaped semiconductor regions formed on the surface thereof, all of which are flat to form wiring and insulating regions patterned by photolithography. The surface to be polished is an insulating film, a metal film, or a mixed surface thereof.

As the polishing pad attached to the polishing head, it is desirable to use the surface of a pad made of nonwoven fabric, polyurethane foam or the like.

As the abrasive, a liquid containing fine particles is desirable. Specifically, silica (SiO 2)
₂ ), alumina (Al ₂ O ₃ ), manganese oxide (MnO)
₂ ), cerium oxide (CeO) and the like, and examples of the liquid include NaOH, KOH, H ₂ O _{2 and the} like. The particle size of the fine particles is preferably 8 nm to 50 nm.
The degree of aggregation of the particles can be controlled by changing the pH of the particles.

When polishing a semiconductor surface, a silica-dispersed sodium hydroxide solution is preferable, when polishing an insulating film, a silica-dispersed potassium hydroxide solution is preferable, and when polishing a metal film such as tungsten, the like. Is preferably aqueous hydrogen peroxide in which alumina or manganese oxide is dispersed.

[0034]

Since the present invention is configured as described above, the following effects can be obtained.

By using a plurality of polishing heads for holding the polishing pad via an elastic thin film forming a pressure fluid chamber communicating with each other, each polishing head automatically equalizes the polishing surface of the polishing pad. In addition, a plurality of polishing pads can be simultaneously brought into contact with the substrate at the same pressure, and the plurality of polishing pads can be brought into contact with the entire surface of the polishing pad at a uniform processing pressure, thereby enabling uniform polishing.

Further, since the polishing head having a smaller diameter is partially brought into contact with the surface to be polished of the substrate for polishing, the polishing head can be rotated at a high speed. Regardless, polishing can be performed at high speed and with high accuracy.

By providing individually adjustable fluid resistors in each of the branches connecting the pressure fluid chamber formed by the plurality of elastic thin films and the solid chamber, the pressure fluid in each pressure fluid chamber can be controlled. Fluctuation and pressure can be temporarily adjusted, the processing pressure can be optimized according to the condition of the substrate and the polishing surface of the polishing pad, and finally, all polishing heads can be uniformly The substrate can be planarized by pressing the substrate with the processing pressure.

Further, in the polishing head of the present invention, the holding, pressurization, equalization, and height adjustment of the polishing pad can be performed by supplying a pressure fluid to a pressure fluid chamber formed by an elastic thin film or adjusting the pressure. Therefore, the mechanism of the polishing head can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing one embodiment of a chemical mechanical polishing apparatus of the present invention.

FIG. 2 is a schematic partial sectional view showing a polishing head according to the present invention.

FIG. 3 is a schematic perspective view showing a conventional chemical mechanical polishing apparatus.

FIG. 4 is a partial cross-sectional view of a conventional Air / Water back work holder.

[Explanation of symbols]

 Reference Signs List 5 rotating table 8 revolving table 10 polishing head 15 polishing pad 17 frame 20 pressure fluid chamber 21 elastic thin film 22 solid chamber

Claims (4)

[Claims] 1. A polishing pad held by a polishing head is brought into contact with a surface to be polished of a workpiece while applying a predetermined processing pressure, and an abrasive is supplied between the polishing pad and the surface to be polished. In a chemical mechanical polishing apparatus that performs polishing, a plurality of polishing heads having an elastic thin film that receives a supply of a pressure fluid to form a pressure fluid chamber, and holding a polishing pad on the lower surface side of the elastic thin film, The chemical mechanical polishing apparatus according to claim 1, wherein the pressure fluid chambers communicate with each other through a solid chamber having a larger capacity than the pressure fluid chamber. 2. A rotary table for holding and rotating a workpiece in a detachable manner, and a rotary table disposed opposite to the rotary table,
A plurality of polishing heads for detachably holding a polishing pad,
A revolving table that revolves the polishing head while supporting the plurality of polishing heads rotatably and movably in the axial direction, a unit that rotates the polishing head, and a unit that moves the polishing head in the axial direction. A polishing pad held by the polishing head is brought into contact with the surface to be polished of the workpiece while applying a predetermined processing pressure, and polishing is performed between the surface to be polished of the workpiece and the polishing pad. In a chemical mechanical polishing apparatus that performs polishing while supplying an agent, each of the polishing heads has an elastic thin film that receives a supply of a pressure fluid to form a pressure fluid chamber, and polishing is performed on a lower surface side of the elastic thin film. The chemical mechanical polishing apparatus, wherein the pad is held, and the pressure fluid chambers communicate with each other through a solid chamber having a larger capacity than the pressure fluid chamber. 3. The chemical mechanical polishing apparatus according to claim 1, wherein the pressure fluid supplied to the pressure fluid chamber formed by the elastic thin film is a gas or a liquid. 4. The apparatus according to claim 1, wherein each of the pipes connecting the pressure fluid chamber and the solid chamber of the plurality of polishing heads is provided with a separately adjustable fluid resistor. 2. The chemical mechanical polishing apparatus according to claim 1.