JPH10175160A - Polishing method and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To polish and remove a projecting part of electric insulating material on the substrate surface without damaging the surface precision by moving a polishing member having a polishing surface of a specified shape onto a surface to be polished in the uniaxial direction with the rotary movement, and pressurizing the polishing member to the surface to be polished to conduct the polishing operation. SOLUTION: A polishing means 12 is a cylindrical member comprising a small diameter part and a large diameter part, and formed by a multilayer resin sheet having polishing power made adhere onto a metal substrate. The rotary movement of a cylinder polishing means 12 is performed by a motor 22. Further, the oscillation of the cylinder polishing means 12 due to rotation of a motor 24 is operated at the predetermined oscillation width, and the surface of a workpiece 2 is polished by the rotary motion and the oscillation. Further, the movement in the direction of X-axis and the movement in the direction of Y-axis by designated pitch after the travel for a designated distance in the direction of Y axis are performed by control means of X and Y stages 8, 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing method and a polishing apparatus for planarizing a glass substrate or a semiconductor substrate such as a silicon wafer.

[0002]

2. Description of the Related Art As semiconductors become more highly integrated, larger in scale and larger in area, semiconductor wirings are becoming finer and more multilayered. Wiring material or insulating material is partially or entirely formed on a flat substrate, but if a multilayer wiring structure is stacked as it is, the unevenness level will increase, and disconnection of wiring,
Defocus of the optical projection device occurs, resulting in defective semiconductor production.

In order to solve this problem, a flattening technique for each surface on which one layer of wiring and an insulating layer are formed has been studied. One of them is a method using a lapping machine, which is an application of a wafer substrate polishing technique. A two-layer pad is attached on a lapping machine, and the entire surface is flattened by uniformly pressing and polishing the substrate.

In this polishing technique, as shown in FIG. 5, an oxide film D serving as a metal wiring B and an insulating film C is formed on a substrate A before polishing.
There is a protrusion step E to which a rigid polishing sheet F is pressed against the substrate surface, and pressure is concentrated on the protrusion portion to selectively remove the protrusion portion to flatten the substrate.

However, since the entire surface of the substrate is warped, if the rigid sheet is pressed as it is, the substrate will be in a partial contact polishing state, and the same location will be polished many times.

To prevent this and uniformly polish the entire surface of the substrate, measures are taken to adjust the hardness of the polishing sheet and correct the warpage of the substrate, but it is difficult to ensure uniformity of the polished surface.

[0007]

In the conventional lapping apparatus, the larger the substrate area, the larger the tool area. However, it is necessary to produce a large polishing tool with good flatness and to simultaneously press the entire surface of the substrate uniformly. Becomes difficult.

Further, if a hard abrasive sheet is used to selectively remove the partial projections, it is difficult to deform the sheet following the warpage of the substrate, and the workability of the entire surface is deteriorated. As a result, a level difference remains or the polishing amount for removing the partial protrusion increases.

Further, in the polishing of a substrate surface having partial projections, there is a problem that polishing liquid hardly enters a central portion of the substrate, polishing heat is accumulated, and deformation due to heat occurs.

The present invention proposes a novel polishing method and a novel polishing apparatus for solving the above-mentioned problem associated with the enlargement of the substrate surface.

Further, the present invention proposes a polishing method and a polishing apparatus which are particularly suitable for polishing the surface of a convex portion of a member to be polished having an uneven step on the surface to be polished.

In particular, the present invention proposes a polishing method and a polishing apparatus suitable for polishing a surface of a silicon wafer of a semiconductor substrate.

[0013]

According to the present invention, a polishing member having a polishing surface having an area surrounded by a small diameter portion and a large diameter portion is rotated on a surface to be polished. The present invention solves the above-mentioned problem by providing a movement motion in a uniaxial direction and applying a polishing operation by pressing the polishing member against the surface to be polished.

Further, a cylindrical polishing means having a polishing portion at an end thereof is pressed against a member to be polished having a portion to be polished on a plane, and the cylindrical polishing means is rotated while rotating the cylindrical polishing means. A polishing method is proposed in which polishing is performed by moving in one direction.

In a polishing apparatus for a member to be polished having a portion to be polished on a plane, a polishing member having a polishing surface having an area surrounded by a small diameter portion and a large diameter portion is polished by the member to be polished. The above object is attained by proposing a polishing apparatus comprising means for applying pressure on a surface, rotating means for rotating the polishing member, and means for moving the polishing member in one direction.

In addition, a polishing apparatus having higher accuracy is proposed by proposing an embodiment provided with a swinging means for giving a swinging motion to the polishing member.

Further, it is proposed that the polishing member is formed at the tip of a cylindrical member.

Furthermore, an embodiment is proposed in which the polishing member at the tip of the cylindrical member has a multilayer structure, and the layer in contact with the surface to be polished is made of a material having a higher elastic modulus than the following layers. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to the drawings.

FIG. 1 shows an apparatus for carrying out the present invention. In the figure, reference numeral 1 denotes a table on which a workpiece is placed, the surface of which is finished to a surface roughness Ra of 5 μm.

Reference numeral 2 denotes a member to be polished, which is a silicon substrate or a member to be polished as shown in FIG.
A wiring member B is wired on a glass substrate A, and an insulating film member C is coated thereon. The substrate side is placed on the table 1.

Reference numeral 4 denotes a base member of the polishing apparatus shown in FIG.
6A and 6B are columns, and 6C is an arm member. Reference numeral 8 denotes an X on which the table 1 is mounted on the base 4 for moving in the X axis direction.
The axis stage 10 moves the table 1 in the Y-axis direction.
The axis stages, M1 and M2 are respective driving motors.

Numeral 12 denotes a polishing means of the present invention, which is a cylindrical member having a small diameter portion d and a large diameter portion D as shown in FIG. It is made from a multilayer resin sheet.

Reference numeral 14 denotes an attachment member made of metal such as stainless steel attached to the upper end of the cylindrical member 12,
Universal joint means 16 at the center of the upper surface of the mounting member 14
Is attached.

The universal joint means 16 is connected to a piston 18A of a cylinder 18 as a pressurizing means.

A rotation drive pin 2 for rotating the cylindrical polishing member 12 at a position near the outer periphery of the upper surface of the mounting member 14
0 is fixed, and the pin 20 is connected to a rotor of a motor 22 held on a mounting member (not shown).

24 is a motor attached to the arm 6C, 26 is a rotating plate attached to the rotor of the motor 24,
Reference numeral 28 denotes an eccentric pin attached to the rotary plate 26, and reference numeral 30 denotes a crank arm. The crank arm 30 has a pin 18B having one end fixed to the eccentric pin 28 and the other end fixed to the upper surface of the cylinder 18. Attach to

Reference numeral 32 denotes a nozzle for injecting a polishing liquid.

FIG. 3 is a control block diagram for controlling the apparatus. The motor drive control means 34 controls the rotation of the cylindrical polishing means 12.

The motor drive control means 36
To control the rotation of

Reference numerals 38 and 40 denote X and Y stages 8 and 1 respectively.
Control means for controlling the movement of zero.

Reference numeral 42 denotes control means for the cylinder 18 of the pressurizing means, and reference numeral 44 denotes means for controlling the injection amount of the polishing liquid.

Numeral 46 denotes a means for controlling the whole of the control means.

A polishing sheet as a polishing tool is fixed to the lower end portion of the cylindrical polishing member 12 in contact with the member to be polished.

The pressure distribution at the contact portion is determined by the workpiece 2 to be polished.
Of the substrate, that is, the radius of curvature of the substrate, the radius of curvature of the tip of the cylindrical member 12 to be used, and the elastic modulus.

If the amount of warpage of the substrate is about 100 μm, the tool contact surface is made flat, and the pressure becomes sufficiently uniform within a contact width of several tens of millimeters with a urethane-based polishing sheet.

In the case of a hard tool such as nylon or a polishing pitch, a uniform pressure is applied within a range of several millimeters, and a high-rigidity tool is used by reducing the width of the annular zone in contact with the tool. Becomes possible.

By changing the width of the radius of the annular zone according to the hardness of the polishing sheet to be used, uniform pressurization becomes possible.

The pressure distribution in the rotational direction of the tool 12 is, for example,
Assuming a perfectly rigid cylindrical flat tool, the substrate is warped, resulting in a three-point contact, and a non-continuous pressure distribution when the tool is not rotating and stationary. However, when the tool 12 is rotated, the pressure is increased in the circumferential direction. And uniform removal processing can be performed.

When an elastic tool such as soft urethane is used, the tool is deformed by the load, the contact width is increased in the circumferential direction, and the uniformity of the polishing removal in the circumferential direction is further improved.

FIG. 2 is a schematic view showing a moving state of the polishing tool 12. The polishing means 12 of the cylindrical member includes a rotating motion U1 around the central axis of the cylindrical member by the motor 22, the motor 24, and the crank arm 30. And a movement U3 of the lapping machine 1 in the X and Y directions by the X and Y stages.

Next, the operation steps of the present apparatus will be described with reference to the flowchart of FIG.

First, the substrate of the member to be processed shown in the figure is held on the table with the protruding portions facing upward.

The substrate is held on the table with a small amount of deformation, such as a method of interposing a highly frictional elastic sheet on the back side or a method of vacuum suction on the back side reference plane.

Next, the piston 18A of the cylinder 18 is lowered to set the polishing sheet attached to the lower end of the cylindrical polishing means 12 at a position where it comes into contact with the upper surface of the workpiece. Step 1

Based on information such as the amount of unevenness of the member to be processed and the hardness of the insulating film, the rotation amounts of the motors 22 and 24, the pressing force of the cylinder 18, the moving speed of the X and Y stages, and the polishing Information necessary for polishing, such as the amount of liquid jetted and the pressure, is input to the control means 46. Step 2

After input of the necessary information, when the apparatus is started, a control signal corresponding to the input information is output from the control means 46 to each control means, so that the polishing liquid is first sprayed onto the workpiece. Then, the rotational movement U1 of the cylindrical polishing means 12 by the motor 22 is performed. Step 3

Further, the swinging movement U2 of the cylindrical polishing means 12 caused by the rotation of the motor 24 operates with a predetermined swinging width, and the above-described rotating movement and the swinging movement perform a polishing operation on the surface of the workpiece.

Further, the X, Y stage control means 40,
The movement in the X-axis direction, the movement in the X-axis direction by a predetermined distance, and the movement in the Y-axis direction by a predetermined pitch are performed by 42.
Step 4

Example 1 A metal wiring B having a thickness of 1 μm was formed on a glass substrate A having a diameter of 300 mm, and a metal wiring B having a thickness of 1.mu.
A workpiece 2 on which an electric insulating film C made of 2 μm Si3N4 is formed is prepared.

The cylindrical member of the polishing means is made of stainless steel and has an inner diameter of 40.0 mm and an outer diameter of 50.0 m.
m, the length of the cylinder is 10.0 mm, and a urethane fiber nonwoven fabric having an inner layer of 1 mm in thickness is attached to the tip of the cylinder, and a 0.5 mm-thick foamed polyurethane sheet is attached thereon as an outer layer.

The rotation speed of the motor 24 is set so that the load of the cylinder 18 is 1000 g, the rotation speed of the cylindrical polishing tool 12 is 600 rpm, and the swing width of the swing means is 10 mm.

The moving speed of the cylindrical polishing tool 12 is 1 per minute.
00 mm and the feed pitch width were set to 10 mm. As a polishing liquid, an alumina fine abrasive was sprayed at a rate of 10 cc per minute.

The workpiece was mounted on the apparatus shown in FIG. 1 and the conditions were input to the control means 46 to perform a polishing operation. Then, the protrusion of the insulating film on the wiring C existing on the entire surface of the substrate was polished to the upper surface of the wiring B, and a partial protrusion was removed to obtain a flat shape.

Example 2 A metal wiring having a thickness of 1 μm was formed on a silicon substrate A having a diameter of 150 mm, and a metal wiring having a thickness of 1.mu.
A member to be polished 2 on which an electric insulating film C made of 2 μm Si3N4 is formed is prepared.

The cylindrical member of the polishing means is made of stainless steel and has an inner diameter of 40.0 mm and an outer diameter of 50.0 m.
m, the length of the cylinder is 10 mm, and a urethane fiber nonwoven fabric having an inner layer of 1 mm in thickness is attached to the tip of the cylinder, and a 0.5-mm-thick foamed polyurethane sheet is attached thereon as an outer layer.

The rotation speed of the motor 24 is set so that the load on the cylinder 18 is 1000 g, the rotation speed of the cylindrical polishing tool 12 is 600 rpm, and the swing width of the swing means is 10 mm.

The moving speed of the cylindrical polishing tool 12 is 3 per minute.
0 mm and the feed pitch width were set to 10 mm. As the polishing liquid, a colloidal silica solution was sprayed at a rate of 20 cc per minute.

The workpiece was mounted on the apparatus shown in FIG. 1, the conditions were input to the control means 46, and the polishing operation was performed. Then, the protrusion of the insulating film on the wiring C existing on the entire surface of the substrate was polished to the upper surface of the wiring B, and a partial protrusion was removed to obtain a flat shape.

[0060]

As described above, according to the present invention, a polishing member having a polishing surface having an area surrounded by a small-diameter portion and a large-diameter portion is rotated and moved in a uniaxial direction on the surface to be polished. And a polishing method in which the polishing member is pressed against the surface to be polished and the polishing operation is performed, whereby the polishing and removal of the protrusions of the electric insulating film material on the substrate surface can be performed without impairing the surface accuracy. Was completed.

Further, a cylindrical polishing means having a polishing portion at an end thereof is pressed against a member to be polished having a portion to be polished on a plane, and the cylindrical polishing means is rotated while rotating the cylindrical polishing means. By moving in one direction and polishing, a polishing method with higher flatness accuracy was obtained.

The present invention also relates to a polishing apparatus for a member to be polished having a portion to be polished on a flat surface, the polishing member having a polishing surface having an area surrounded by a small diameter portion and a large diameter portion. And a means for rotating the polishing member, and a means for moving the polishing member in one direction.

By providing a swinging means for giving a swinging motion to the polishing member, it is possible to ensure uniformity of the processing accuracy of the polished surface.

Further, according to the present invention, the polishing member at the tip of the cylindrical member has a multilayer structure, and the layer in contact with the surface to be polished is made of a material having a higher elastic modulus than the following layers. By using a high-rigidity abrasive sheet on the side and generating a high pressure at the partial projections of the substrate to remove the projections, it was possible to increase the flattening application of the surface to be processed.

Further, the present invention is a polishing tool having a high peripheral speed by using an annular tool, and can obtain a uniform contact pressure against the warpage of the substrate, so that the entire surface can be uniformly polished in a short time. Was.

[Brief description of the drawings]

FIG. 1 is an explanatory view of an apparatus configuration for performing a polishing method of the present invention.

FIG. 2 is a view for explaining the movement of a polishing tool means in the present invention.

FIG. 3 is a control block diagram of the apparatus of FIG. 1;

FIG. 4 is a flowchart illustrating an operation.

FIG. 5 is a diagram illustrating a configuration of a workpiece to be polished in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lapping machine 2 Workpiece 8, 10 X, Y stage 12 Cylindrical member-shaped processing tool (polishing means) 18 Cylinder 22, 24 Motor

Claims (6)

[Claims] A polishing member having a polishing surface having an area surrounded by a small-diameter portion and a large-diameter portion is provided with a rotating motion and a uniaxial moving motion on a surface to be polished, and the polishing member is fixed to the polishing member. A polishing method characterized in that a polishing operation is performed by applying pressure to a surface to be polished. 2. A method in which a cylindrical polishing means provided with a polishing portion at an end thereof is pressed against a member to be polished having a portion to be polished on a plane, and the polishing means is rotated while rotating the cylindrical polishing means. A polishing method characterized in that the polishing is carried out by moving in one direction. 3. An apparatus for polishing a member to be polished having a portion to be polished on a plane, the member having a polishing surface having an area surrounded by a small diameter portion and a large diameter portion. A polishing apparatus comprising: means for applying pressure on a surface to be polished; means for rotating the polishing member; and means for moving the polishing member in one direction. 4. The polishing apparatus according to claim 3, further comprising swing means for giving a swing motion to said polishing member. 5. The polishing apparatus according to claim 5, wherein said polishing member is formed at a tip of a cylindrical member. 6. The polishing member at the tip of the cylindrical member has a multilayer structure, and a layer in contact with the surface to be polished is made of a material having a higher elastic modulus than the following layers. The polishing apparatus according to claim 5.