JP2001277097A - Polishing device and polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device which minimizes the displacement of a retainer ring in a relative moving direction by a polishing friction, to improve the flatness at a substrate peripheral part, and to easily clean and remove a polishing fluid collecting in an inner peripheral surface of the retainer ring. SOLUTION: A polishing device which polishes a material 11 to be polished by pressing it against the abrasive 21 and relatively moving it against the abrasive 21 is provided with a material to be polished pressing means 4 which presses the material 11 to be polished against the abrasive 21, a retainer ring pressing means 6 which presses a retainer ring 3 against the abrasive 21, an abrasive pressing means 2 which presses the abrasive 21 against the material 11 to be polished and the retainer ring 3, a material to be polished pressing force controlling means 24 which controls the pressure for pressing the material 11 to be polished, a retainer ring pressing force controlling means 25 which controls the pressure for pressing the retainer ring 3, and an abrasive pressing force controlling means 26 which controls the pressure for pressing the abrasive 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polishing apparatus. In particular, in the step of performing laminated wiring on the surface of a wafer, a glass substrate, an electronic component, etc., while supplying abrasive grains to a convex portion or the like generated on the surface of an intermediate insulating layer formed on a circuit such as a wiring. The present invention relates to a polishing apparatus for performing precision polishing such as polishing and flattening.

[0002]

2. Description of the Related Art A polishing apparatus shown in FIG. 7 disclosed in Japanese Patent Application Laid-Open No. 08-339979 has an elastic polishing pad 101 adhered to the upper surface of a rotatable surface plate 100. A substrate holding device 103 for holding the substrate 102 on the lower surface is disposed above the substrate. The substrate holding device 103 is attached to a rotating shaft 104, a columnar substrate holding head 105 provided integrally with the lower end of the rotating shaft 104 to hold the substrate 102, and a peripheral portion on the lower surface of the substrate holding head 105. It has a ring-shaped lip seal 106 made of an elastic body and a ring-shaped retainer ring 107 attached to the outside of the lip seal 106. This polishing apparatus uses the polishing pad 10
After being press-bonded to the substrate 1, the pressurized fluid is introduced downward from above in the axial direction through the fluid channel 108 inside the rotary shaft 104, and is supplied to the space 109 formed on the back side of the substrate 102, and is held. The substrate 102 is pressed against the polishing pad 101 and polished.

[0003] However, this polishing apparatus does not
When the substrate is held by the substrate holding device 103, the contact surface of the retainer ring 107 with the polishing pad 101 is preset so as to have a predetermined step with the polishing surface of the substrate 102 positioned by the lip seal 106, Substrate 10
Every time polishing 2 is repeated, the height of the retainer ring 107 wears due to the relative movement of the contact with the polishing pad 101,
The contact surface between the polished surface of the substrate 102 and the retainer ring 107 is not a predetermined step, and the step is enlarged. As a result, the pressing force of the polishing pad 101 in the vicinity of the outer periphery of the substrate 102 by the retainer ring 107 is reduced, and the flat area of the polishing pad 101 is reduced. Further, the polishing liquid easily accumulates in the corner 110 formed by the inner peripheral surface of the retainer ring 107 and the substrate contact surface of the lip seal 106, and the retained polishing liquid is removed from the space 109 by the lip seal 106. There is another problem that the pressurized fluid flowing out through the substrate is dried and agglomerated, and the aggregated and dried product of the retained polishing liquid easily causes scratches, which are serious defects in quality, on the substrate 102.

[0004] Japanese Patent Application Laid-Open No. 09-22581 shown in FIG.
The polishing apparatus disclosed in No. 8 presses the substrate 102 supported by the carrier 111 against the polishing pad 101 on the surface of the surface plate 100 with a constant pressure by the fluid introduced into the space 109, The substrate 102 is polished while the retainer ring 107 surrounding the periphery and vertically movable is pressed against the polishing pad 101 by a fluid introduced into the space 109 with a predetermined pressing force smaller than the predetermined pressure. So that the pad 101 is in sliding contact
The platen 100 and the carrier 111 are relatively moved. The retainer ring 107 prevents the protrusion of the substrate 102 from the carrier 111 and abnormal polishing of the substrate 102, and does not change the polishing characteristics even if the thickness of the substrate 102 is different, and the contact surface of the retainer ring 107 is polished. There is no need for height position adjustment.

[0005] This polishing apparatus solves the above-mentioned problem of the polishing apparatus, in which the polishing characteristics are hardly changed even if the thickness of the substrate 102 is different, by a retainer ring 107 provided movably in the vertical direction. The position of the retainer ring 107 and the carrier 111 delicately change in the relative movement direction due to the frictional force caused by the relative movement of the polishing pad 101 and the polishing pad 101, and the space surrounded by the inner peripheral surface of the retainer ring 107 and the carrier 111 is moved from a predetermined position. Change. For this reason, there is a problem that it is difficult to transfer and load the substrate 102 into this space by an automatic transfer device such as a robot.

Further, another polishing apparatus is disclosed in
There is a polishing apparatus disclosed in Japanese Patent No. 58309 and shown in FIG. Surface plate 10 with polishing pad 101 stuck on top
0 and a top ring 112
Is a back sheet 113 made of an elastic material such as a sponge.
Then, the substrate 102 is pressed against the polishing pad 101 with a predetermined force. The polishing apparatus includes a retainer ring 10 around a top ring 112 having a recess for accommodating the substrate 102.
7 is arranged so as to be movable up and down, and a pressing means (not shown) for pressing the retainer ring 107 against the polishing pad 101 is provided, and the pressing force of the pressing means is made variable. Accordingly, the retainer ring 107 applies an optimal pressing force to the polishing pad 101 in accordance with the material to be polished 102 and the polishing conditions, thereby preventing an excessive or insufficient amount of polishing at the peripheral portion of the substrate 102 and improving flatness. By performing high polishing, it can be made flat and mirror-finished.

In this polishing apparatus, the retainer ring 107 and the substrate 102 are separately pressed against the polishing pad 101 with an optimal pressing force, so that the amount of polishing at the peripheral portion of the substrate 102 can be reduced. However, the deformation size of the polishing pad 101 that is deformed by the pressing force is much smaller than the gap size between the retainer ring 107 and the substrate 102,
The effect of improving the flatness of the substrate 102 was not sufficient. In addition, the structure is complicated to realize the vertical movement of the retainer ring 107, and a mechanical sliding portion is required, and dust is generated from this, which has a serious effect on the polishing quality of the substrate 102. . In order to prevent the generation of dust, there is a problem that a more complicated structure is required.

[0008]

Therefore, as a solution to such a problem, conventionally, a polishing pad of a retainer ring is used every time a predetermined number of wafers are polished or each time a processing lot of a wafer is changed. The height of the retainer ring has been adjusted so that the contact surface with the surface is flush with the polished surface of the wafer whose back surface is positioned by the lip seal. In addition, every time polishing of the wafer is completed, the polishing liquid accumulated in the corner formed by the inner peripheral surface of the retainer ring and the wafer contact surface of the lip seal is removed by washing, and the dry aggregation of the retained polishing liquid is reduced. In order to reduce the amount of fluid flowing out of the lip seal portion, the pressure of the fluid supplied from the back surface facing the wafer was adjusted to be small, but with such conventional adjustment, a satisfactory polishing result on the wafer is expected. The production yield decreases, the equipment operation rate decreases due to adjustment, and the polishing liquid accumulated in the corner formed by the inner peripheral side surface of the retainer ring and the wafer contact surface of the lip seal is completely removed. It is difficult to remove them by washing, and improvement has been desired for many years.

Further, by setting the gap between the inner periphery of the retainer ring and the substrate larger than the amount by which the position of the retainer ring and the carrier movably provided in the plate thickness direction changes in the relative movement direction, the transfer mounting by a robot or the like is possible. However, the substrate moves greatly within the retainer ring due to the frictional force due to the relative movement of the substrate and the polishing pad, and the relative displacement between the substrate and the carrier easily causes scratches on the back surface of the substrate. Improvements over the years have been desired.

[0010] Further, in the peripheral portion of the substrate where the flatness is not sufficient due to the excessive or insufficient polishing amount at the peripheral portion of the substrate, a reduction in yield is accepted as a matter of course, and it must be finally discarded as a portion not used as a product. Rather, improvements have been desired for many years.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and it is intended to reduce displacement of a retainer ring in a relative movement direction due to polishing friction with an abrasive, and to improve flatness at a peripheral portion of a substrate. It is another object of the present invention to provide a polishing apparatus and a polishing method capable of easily cleaning and removing a polishing liquid accumulated on an inner peripheral surface of a retainer ring.

[0012]

As a means for solving the above-mentioned problems, the present invention relates to a method for polishing a disk-shaped material to be polished which is held on one side by a holding member and which is surrounded by a retainer ring. In the polishing apparatus for polishing by moving the material to be polished relatively to the polishing material,
Polishing material pressing means for pressing the material to be polished against the polishing material, retainer ring pressing means for pressing the retainer ring to the polishing material, and polishing for pressing the polishing material to the polishing material and the retainer ring Material pressing means, material-to-be-polished pressing force control means for controlling the pressure of the material-to-be-polished pressing means for pressing the material to be polished, and retainer ring for controlling the pressure of the retainer ring pressing means for pressing the retaining ring A pressing force control means and an abrasive pressing force control means for controlling a pressure of the abrasive pressing means for pressing the abrasive are provided.

In the above invention, a pressing means for pressing the material to be polished, the retainer ring and the abrasive, and a pressing force control means for controlling the pressing pressure are provided, and the pressing pressures are controlled to equalize the respective pressures. By doing so, the contact surface formed by pressing the material to be polished and the abrasive and the retainer ring and the abrasive can be positioned on the same plane, and the distribution of the pressure acting on the contact surface becomes continuous and uniform. Further, it is also possible to increase the pressing pressure on each contact surface by the pressing force control means while keeping the contact surfaces on the same plane. By performing polishing in this state, polishing with good flatness can be performed.

Preferably, the abrasive pressing means is pressed by a fluid pressure acting on the back surface of the abrasive. As described above, by pressing the abrasive with the fluid, the abrasive can be deformed and made to conform to the surface of the opposed material to be polished, and the pressure for pressing the entire abrasive can be applied uniformly.

It is preferable that the polished material pressing means presses by a fluid pressure acting on the back surface of the polished material.
As described above, by pressing the material to be polished with the fluid, the material to be polished is deformed so as to conform to the surface of the opposed abrasive material, and the pressure for pressing over the entire material to be polished can be applied uniformly. .

It is preferable that the retainer ring pressing means presses by a fluid pressure acting on a back surface of the retainer ring. As described above, since the retainer ring is pressed by the fluid, control of the press can be facilitated by adjusting the fluid.

Further, it is preferable to provide a pressing force balance control means for controlling the pressures controlled by the polishing target pressing force control means, the retainer ring pressing force control means and the abrasive pressing force control means. As described above, since the pressing force balance control means is provided to control the balance of each pressing pressure, it is possible to perform the polishing desired by the user. For example, to reduce the amount of polishing on the outer peripheral portion of the workpiece,
This can be achieved by increasing the pressure for pressing the retainer ring. Further, for the purpose of preventing dry aggregation of the polishing liquid in an apparatus using a fluid for pressing the workpiece,
Even when the pressure of the fluid is reduced and the amount of the fluid flowing out is reduced, the pressure to be polished by the material to be polished and the pressure to be pressed by the retainer ring can be maintained equal to make the polishing surface coplanar. Similarly, even if a fluid flows out of a predetermined amount or more due to a warp of the material to be polished and the pressure for pressing the material to be polished is reduced, the pressure for pressing the material to be polished and the pressure for the retainer ring are pressed. The pressure and the pressure applied by the abrasive can be maintained at a predetermined ratio. Further, even if the dimensions of the material to be polished, the retainer ring, and the size of the abrasive are changed due to abrasion caused by the polishing, the ratio of the predetermined pressing pressure can be maintained.

It is preferable that the abrasive pressing means presses the abrasive via a diaphragm. As described above, by pressing the abrasive with the fluid through the diaphragm, the distribution of the pressure applied to the abrasive is continuous and uniform, and the abrasive is pressed without directly touching the fluid, and the abrasive is replaced. Becomes easier.

It is preferable that the outer peripheral portion of the diaphragm is thicker than the inner portion. As described above, by making the outer peripheral portion of the diaphragm thicker than the inner side, a large displacement in the pressing direction can be obtained with a small pressing pressure,
The flatness of the abrasive can be obtained by the swelling of the inner portion of the diaphragm.

It is preferable that the polished material pressing means has an annular lip seal on an outer peripheral portion of a back surface of the polished material. In this way, by providing the lip seal on the outer peripheral portion of the surface to be polished of the material to be pressed, when the material to be polished is pressed by the fluid, the surface to be pressed of the material to be polished is filled with the fluid and substantially sealed. A space serving as a space can be formed.

It is preferable that the holding member has a thin plate member attached in parallel to the polishing surface of the workpiece, and the retainer ring is cantilevered by the plate member. In this way, by supporting the retainer ring in a cantilever manner via the horizontally attached plate member, the displacement of the retainer ring in the horizontal direction is prevented by the elastic force due to the curvature of the plate member. High rigidity, the horizontal position of the retainer ring does not change. In addition, the deflection in the vertical direction of the retainer ring is easily changed by a thin plate member, and has low rigidity.
Even a small force can move the retainer ring vertically.

Preferably, the plate member has a donut shape, and is supported by the holding member at an outer peripheral portion, and the retainer ring is cantilevered by an inner peripheral portion. As described above, the plate member has a donut plate shape, is supported by the base at the outer peripheral portion, and cantileverly supports the retainer ring by the inner peripheral portion of the plate member, so that the retainer ring can be uniformly supported over the entirety. . Further, even with a thin plate member, the torsional load acting on the plate member does not become a compressive load on the plate member, but becomes a tensile load at all times. Hateful.

It is preferable that the retainer ring pressing means is made of an elastic body formed in a balloon shape, and that the fluid is injected into the elastic body to inflate the elastic body to press the retainer ring. In this way, by injecting fluid into the retainer ring pressing portion made of an elastic body formed in a balloon shape and inflating it, and pressing the retainer ring, the retainer ring is pressed with a pressure that can be adjusted to a desired pressure. can do. Further, the retainer ring pressing portion does not require a sliding portion.

Preferably, the elastic body has a donut shape. As described above, since the retainer ring pressing portion has a donut shape, fluid can be injected into the retainer ring pressing portion, and the retainer ring can be uniformly pressed over the entirety.

A plurality of circumferential holes are formed in the inner and outer peripheral portions of the plate member, and concave and convex portions fitted through the holes are formed in the retainer ring and the holding member. It is preferable to hold the hole of the plate member in the uneven portion. In this manner, holes along the circumference are formed in the inner and outer peripheral portions of the plate member, and the concave and convex portions that fit into the holes are formed in the retainer ring and the base, and the holes of the plate member are sandwiched between the concave and convex portions. By doing so, the plate member supports the retainer ring and the base in the horizontal direction through the contact portion along the circumferential direction, and the force applied in the horizontal direction at the contact portion is evenly distributed. Thereby, deformation due to buckling of the plate member can be reduced.

It is preferable that a claw-shaped protruding portion is provided in the hole so as to protrude in the radial direction of the plate member, and the protruding portion elastically supports the protruding portion in the radial direction. As described above, when the claw-shaped protrusion is provided and the retainer ring and the protrusion of the base are fitted into the holes, the protrusion is deformed by the protrusion, and the protrusion elastically supports the protrusion in the horizontal direction. . Thus, the protruding portion is deformed by a horizontal force applied at the time of processing, and deformation due to buckling can be prevented.

[0027] The convex portion of the retainer ring is supported from one of radially inner and outer sides of the opposing projecting portions, and the convex portion of the base is opposite to the direction in which the convex portion of the retainer ring is supported. Preferably, it is supported from the side. In this manner, the convex portion of the retainer ring is supported from one of the radially inner and outer sides of the opposing projecting portions, and the convex portion of the base is supported from the side opposite to the direction in which the convex portion of the retainer ring is supported. By doing so, any one of the projections comes into contact with the plate member on only one side, so when removing the retainer ring, the retainer ring can be easily removed without plastically deforming the plate member only by elastically deforming the protrusion. Can be removed.

It is preferable that the base is provided with a cleaning mechanism for cleaning by ejecting a fluid to an inner peripheral portion of the retainer ring. Thus, by providing the cleaning mechanism for ejecting the fluid to the inner peripheral portion of the retainer ring, the inner peripheral portion of the retainer ring can be easily cleaned.

Preferably, a step is provided on an inner peripheral portion of the retainer ring facing the outer peripheral surface of the material to be polished.
In this manner, by providing the step on the inner peripheral portion of the retainer ring, the retainer ring has a portion where the gap between the material to be polished and the retainer ring is large, and the fluid flows into the gap by capillary action or surface tension. Can be prevented from accumulating.

It is preferable that an outflow passage for discharging the fluid used in the abrasive pressing means to the outside of the retainer ring is provided on the lower surface of the retainer ring. in this way,
By providing an outflow path for discharging the fluid used in the abrasive pressing means to the outside of the retainer ring on the lower surface of the retainer ring, the fluid can be discharged from the retainer ring to the outside.

Further, as a means for solving the above-mentioned problems, the present invention provides a method of pressing a disk-shaped material to be polished which is held on one side by a holding member and which is surrounded by a retainer ring. In a polishing apparatus for polishing by moving the workpiece relative to the abrasive, the abrasive is pressed against the abrasive, the retainer ring is pressed against the abrasive, and the abrasive is Pressing the material to be polished and the retainer ring, controlling the pressure for pressing the material to be polished, controlling the pressure for pressing the retainer ring, controlling the pressure for pressing the material for polishing, The polishing target material is polished by the polishing material while controlling the balance between the retainer ring and the pressure pressing the polishing material.

[0032]

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

FIG. 1 is a schematic structural view of a polishing apparatus according to the present invention. This polishing apparatus comprises a holding base 1 and a platen 2
And a retainer ring 3.

The holding base 1 is, as shown in FIG.
It has a columnar portion 1a and a disk portion 1b integrally provided at the lower end of the columnar portion 1a, and has a columnar wafer base 4 provided integrally below the disk portion 1b. The holding base 1 includes a cylindrical housing 1 and a cylindrical housing 1a.
And is held by the housing 5 in a vertically movable and horizontally rotatable manner by a control device (not shown). Further, the disk portion 1b has a retainer ring pressing portion 6 and a displacement control portion 7 extending downward on the outer peripheral portion.

The wafer base 4 has therein a back pressure passage 8 through which compressed air passes. The back pressure passage 8 has an opening 8 a on the lower surface of the wafer base 4. In addition, the wafer base 4 has an air reservoir 9 formed on the lower surface thereof, which is formed as a recess for retaining a part of the compressed air discharged from the back pressure passage 8. Further, the wafer base 4 has an annular lip seal 10 attached to the outer peripheral portion of the lower surface thereof with a double-sided tape or the like. A substantially closed space 12 is formed between the lower surface of the base 4. Further, as shown in FIG. 4, an opening 4a is provided on the side surface of the columnar shape, and a cleaning nozzle 13 for jetting ultrapure water to the outside is provided in the opening 4a.

The retainer ring pressing portion 6 has an opening 6a formed along the circumferential direction on the lower surface of the outer peripheral portion of the disk portion 1b, and an air flow is formed so that compressed air is sent downward to the opening 6a. It has a road 15. The air passage 15 has a relief valve 14 for adjusting pressure.
Further, the retainer ring pressing portion 6 has an inner peripheral portion such that a donut plate-shaped balloon-shaped elastic body 16 made of an elastic body such as a silicon rubber plate having a thickness of about 0.1 mm closes the opening 6a. The outer peripheral portion is attached to the lower surface of the disk portion 1b by donut-shaped pressing plates 17a, 17b. The balloon-like elastic body 16 expands when compressed air is sent out from the air flow path 15.

The displacement control section 7 comprises a cylindrical section 7a and a projecting section 7b extending inward from the lower end of the cylindrical section 7a. The disk portion 1b is fixed to the lower surface of the outer peripheral portion. Further, as shown in FIG.
The upper surface has a plurality of convex portions 7c along the circumferential direction at regular intervals, and the connecting portion 18 has a concave portion 18a on the lower surface in which the convex portion 7c is fitted. A connection plate 19 is sandwiched between the displacement control unit 7 and the connection unit 18 so that the connection unit 18
It is integrally fixed to the connecting plate 19 by a bolt inserted from the upper surface.

The connecting plate 19 is in the form of a donut plate and has a diameter of about 0.1 mm.
A plate made of a corrosion-resistant material such as a stainless steel plate or a Hastelloy plate having a thickness of 1 mm. A plurality of outer peripheral holes 19b into which the convex portions 7c of the displacement control unit 7 are fitted, and a plurality of radial holes 19c radially provided at equal intervals in the circumferential direction and radially are formed. The radial holes 19c are formed so that the connecting plate 19 can be easily deformed into a truncated cone shape. The inner edge of the inner peripheral hole 19a and the outer peripheral edge of the outer peripheral hole 19b are
Each has claw-shaped claw portions 19d and 19e. FIG.
As shown in FIG. 7, when the convex portion 7c of the displacement control portion 7 is fitted into the concave portion 18a of the connecting portion 18 through the outer peripheral hole 19b, the claw portion 19d is deformed on the radially outer side and press-fitted (for example, It is formed so as to have a press fit allowance of about 0.1 mm and a clearance fit (for example, a clearance allowance of about 0.1 mm) inside in the radial direction.

The platen 2 has a cylindrical shape having an opening 2a at the upper end, and has a diaphragm 20 made of a stainless steel plate or the like that seals the opening 2a. A polishing pad 21 for polishing the wafer 11 is bonded and fixed to the upper surface of the diaphragm 20 using a double-sided tape or the like. The diaphragm 20 has a step portion 20a on the lower surface, and the inner side is thinner than the outer peripheral portion (about 0.4 mm).
It is formed to a thickness of 2 mm. The diaphragm 20 is fixed to the platen 2 by bolts, and the polishing pad 21 is fixed to the platen 2 by bolts via a fixing member 22.

The retainer ring 3 is mounted on the wafer 11
It has a slightly larger (about 0.1 mm) inner diameter and has a cylindrical shape having a step portion 3a of about 5 mm protruding inward on the inner peripheral surface of the lower end. The retainer ring 3 is connected to the connecting plate 1.
The inner peripheral portion 9 is sandwiched by a connecting plate 23 and integrally fixed by bolts. Further, as shown in FIG. 3, the retainer ring 3 has a concave portion 3b along the circumferential direction on the upper end surface and a projecting portion 3c protruding outside the outer peripheral surface. The connecting part 2
3 has a convex portion 23a fitted on the concave portion 3b on the lower surface. On the lower surface of the retainer ring 3, radial grooves 3d (for example, 24 grooves formed with a width of 2 mm and a depth of 2 mm at equal intervals over the circumference) are formed as outflow paths of compressed air. As shown in FIG. 6, when the convex portion 23a of the connecting portion 23 is fitted into the concave portion 3b of the retainer ring 3 through the inner peripheral hole 19a, the claw portion 19e is deformed on the radially inner side and press-fitted. It is formed so as to be fitted (for example, a press fitting allowance of about 0.1 mm) and to be a gap fit (for example, a gap allowance of about 0.1 mm) on a radially outer side.

Further, the polishing apparatus according to the present invention has a structure shown in FIG.
As shown in FIG. 2, a precision electronic regulator 2 for controlling the pressure of compressed air supplied to the substantially closed space 12 on the back side of the wafer 11 through the back pressure flow path 8
4, a precision electronic regulator 25 for controlling the pressure of compressed air supplied to the back side of the balloon-like elastic body 16 through the air flow path 15, and a back side of the polishing pad 21 via the diaphragm 20. A precision electronic regulator 26 for controlling the pressure of the supplied compressed air; and a balance controller for controlling the pressure of each precision electronic regulator to a preset value based on a measurement value measured by a pressure sensor (not shown). 2
And 7.

Next, the operation of the polishing apparatus having the above configuration will be described.

As shown in FIG. 5, when the holding base 1 is raised, the balloon-like elastic body 16 is compressed by an extremely weak pressure (for example, 0.05 kg / cm ² ) controlled by a precision electronic regulator 25. After expansion, the retainer ring 3 is lowered until the projection 3c comes into contact with the projection 7b of the displacement control unit 7. At this time, the balloon-like elastic body 16 made of a silicon rubber plate having a thickness of about 0.1 mm expands even with compressed air of low pressure, and the retainer ring 3 is cantilevered by the connecting plate 19. Since it has high rigidity in the horizontal direction but low rigidity in the vertical direction, it is pressed by the balloon-like elastic body 16 and easily descends. After the wafer 11 is loaded and loaded on the center of the upper surface of the polishing pad 21 by a wafer loading / unloading robot (not shown), the substantially sealed space 12 of the wafer base 4 is made negative pressure by the precision electronic regulator 24, and the wafer 11 is It is adsorbed below the wafer base 4.

After the wafer loading / unloading robot retreats and presses the polishing pad 21 with a pressure of, for example, 0.1 kg / cm ² under the control of the precision electronic regulator 26, the wafer base 4 is The surface is lowered until the surface contacts the polishing pad 21. At this time, the retainer ring 3 is pressed upward by the polishing pad 21 and rises until the polishing surface of the wafer 11 and the lower surface of the retainer ring 3 are on the same plane.

When the polishing surface of the wafer 11, the lower surface of the retainer ring 3, and the upper surface of the polishing pad 21 are flush with each other, the pressure applied to the polishing pad 21 (0.1
kg / cm ² ), the precision electronic regulator 24 controls the substantially sealed space 12 which generates a pressing force perpendicular to the wafer 11 to a positive pressure, and compresses compressed air by the precision electronic regulator 25 to 0.1 kg / cm ^2. Injection and pressure into the balloon-like elastic body 16 with the pressure of
Is pressed against the polishing pad 21. Further, the balance controller 27 sets the pressure for pressing each of the wafer 11, the retainer ring 3, and the polishing pad 21 to 0.1 kg / cm.
Balance control to ² . The wafer 11 is pressed by compressed air from the back surface to follow the upper surface of the polishing pad 21, and the polishing pad 21 is pressed by the diaphragm 20 and deformed to follow the polished surface of the wafer 11, and the pressure is uniformly applied to the polished surface. Take it. Further, since the inner portion of the diaphragm 20 is thinner than the outer peripheral portion, the inner portion is easily expanded by compressed air, and the surface of the polishing pad 21 that contacts the wafer 11 can be flattened.

Thereafter, the polishing pad 21 and the wafer base 4
Is relatively moved by, for example, translational orbital motion, and gradually increased to a predetermined relative speed (for example, 1000 mm / sec), and at the same time, the balance controller 27 controls the pressure balance to a preset value, and The compressed air control pressure of the regulators 24, 25, 26 is increased to a predetermined pressure (for example, 0.4 kg / cm ² ), and the wafer 11 is maintained in a state where the polished surface of the wafer 11 and the lower surface of the retainer ring 3 are kept on the same plane. Is performed. At this time, the wafer 11 is
Since the polishing pad 21 and the polishing pad 21 are pressed against each other and are balanced, the protrusion to the outside of the retainer ring 3 is prevented.
Further, since the polishing is performed while the polished surface of the wafer 11 and the lower surface of the retainer ring 3 are maintained on the same plane, polishing with excellent flatness can be performed. Further, when the compressed air flows out of the lip seal 10 in the substantially closed space 12 due to the warp of the wafer 11 or the like, the compressed air is discharged to the outside of the retainer ring 3 from the radial groove 3d provided on the lower surface of the retainer ring 3. Thus, the pressing force of the compressed air inside the retainer ring 3 is not disturbed and the wafer 11
Can be pressed uniformly. Also, the polishing liquid that has come out of the polishing surfaces of the wafer 11 and the polishing pad 21 can be discharged by the air current effect of the compressed air. As a result, the polishing liquid heated to a high temperature by polishing does not solidify,
The occurrence of scratches can be prevented.

As shown in FIG. 6, the inner peripheral hole 1 of the connecting plate 19
A radially inner claw 19e of the connecting portion 9a elastically supports the convex portion 23a of the connecting portion 23 radially outward, and a radially outer claw 19d of the outer peripheral hole 19b corresponds to the convex portion 7d of the displacement control portion 7.
c is elastically supported radially inward. This prevents the retainer ring 3 from being displaced in the horizontal direction due to the horizontal frictional force applied between the retainer ring 3 and the polishing pad 21, and always performs centering with respect to the retainer ring 3 to position the retainer ring 3 at a predetermined position. it can.

The polishing process can be changed while observing the polishing status of the wafer 11. For example, when it is desired to reduce the amount to be polished on the outer peripheral portion of the wafer 11, it is possible to respond by increasing the pressure for pressing the retainer ring 3. Further, even when the amount of fluid flowing out of the compressed air is reduced for the purpose of preventing dry aggregation of the polishing liquid, by maintaining the pressure for pressing the wafer 11 and the pressure for pressing the retainer ring 3 equal,
The polished surface and the lower surface of the retainer ring can be maintained on the same plane. Also, the compressed air flows out of a predetermined amount or more due to the warpage of the wafer 11 and the like, and the wafer 11 is removed from the polishing pad 2.
When the pressure for pressing the wafer 1 decreases, the pressure for pressing the retainer ring 3 and the pressure for pressing the polishing pad 21 can be reduced to maintain the pressure for pressing the wafer 11 at a predetermined ratio.

When the above-mentioned polishing process is completed, the relative movement between the polishing pad 21 and the wafer base 4 is stopped, and the wafer 11 and the retainer ring 3 are moved to, for example, 0.05 kg / c.
precision electronic regulator 2 so as to press at a pressure of m ²
By controlling the pressures 4 and 25, the wafer base 4 is raised to a predetermined position where the wafer loading / unloading robot can unload the wafer 11. At this time, the retainer ring 3 descends until it slightly comes into contact with the projection 7b of the displacement control unit 7, and the wafer 11 is separated from the wafer base 4 and remains on the upper surface of the polishing pad 21. After the wafer loading / unloading robot unloads the wafer 11, ultrapure water is ejected from the cleaning nozzle 13,
The polishing liquid collected near the corner formed by the inner peripheral surface of the retainer ring 3 and the lip seal 10 is washed and removed. At this time, the ultrapure water flows through a gap formed between the retainer ring 3 and the wafer base 4 due to the lowering.
It is easily discharged downward without surface tension.

When the retainer ring 3 is worn by polishing, the claw portion 19e on the inner side in the radial direction of the inner peripheral hole 19a of the connecting plate 19 and the claw portion 19d on the outer side in the radial direction of the outer peripheral hole 19b are elastically deformed. By bending the retainer ring 3 within the range, the retainer ring 3 can be easily replaced. further,
When the retainer ring 3 is attached, the retainer ring 3 is centered at an appropriate position by the claw 19d.

[0051]

As is clear from the above description, according to the present invention, the contact surfaces formed by pressing the material to be polished and the abrasive and the retainer ring and the abrasive are positioned on the same plane.
Polishing by increasing the pressure at each contact surface,
The material to be polished is polished with excellent flatness. In addition, pressure is exerted on the contact surface between the retainer ring and the abrasive material, and there is no gap between the retainer ring and the abrasive material, so that the material to be polished jumps out of the retainer ring in the planar direction during polishing. Can be prevented.

In particular, by pressing the abrasive with the fluid, the pressure applied to the abrasive is evenly applied, and uniform polishing can be performed from the center to the peripheral edge of the workpiece.
Polishing excellent in flatness can be performed.

In particular, when the material to be polished is pressed by the fluid, the pressure applied to the material to be polished is evenly applied, and uniform polishing can be performed from the central portion to the peripheral portion of the material to be polished. Excellent polishing can be performed.

In particular, since the retainer ring is pressed by the fluid, control of the pressing can be facilitated by adjusting the fluid.

In particular, since the pressing pressure balance is controlled by providing the pressing force balance control means, the polishing desired by the user can be performed.

In particular, when the abrasive is pressed by the fluid through the diaphragm, the distribution of the pressure applied to the abrasive becomes continuous and uniform. Therefore, the abrasive is pressed without directly contacting the fluid to maintain the flatness. can do. Further, replacement of the abrasive is facilitated.

In particular, by making the outer peripheral portion of the diaphragm thicker than the inner side, it is possible to obtain the flatness of the polishing material, and at the same time, it is possible to achieve both the followability of the polishing pad and the flatness of the polishing material.

In particular, by supporting the retainer ring in a cantilever manner via a horizontally attached plate member, the retainer ring can be supported with high rigidity in the horizontal direction and low rigidity in the vertical direction. Since the retainer ring is not displaced in the horizontal direction, the position of the retainer ring is constant and the robot can easily grip the wafer. Further, the retainer ring can be moved up and down by a small force, and a sliding portion for fixing the retainer ring in the up and down direction is not required.

In particular, by forming holes along the circumference at the inner and outer peripheral portions of the plate member, and sandwiching the holes of the plate member with the concave and convex portions fitted into the holes, the plate member can be connected to the retainer ring. The base is supported in the horizontal direction through the contact portion along the circumferential direction, and the force applied in the horizontal direction at the contact portion is evenly dispersed, so that deformation due to buckling of the plate member can be reduced. it can.

In particular, by providing a claw-shaped protruding portion that protrudes oppositely in the hole of the plate member, and fitting the retainer ring and the convex portion of the base into the hole, it is possible to reduce the horizontal force applied during processing. The protruding portion is deformed to prevent deformation due to buckling, and the position of the concave portion and the hole when the convex portion is fitted into the concave portion due to a processing error when processing the hole of the plate member. The problem can be solved by elastically deforming the protrusion, and the retainer ring can be positioned at a desired position.

In particular, by providing a cleaning mechanism for ejecting a fluid to the inner peripheral portion of the retainer ring, the inner peripheral portion of the retainer ring can be easily cleaned, and the accumulated polishing liquid can be cleaned and removed.

In particular, by providing a step on the inner peripheral portion of the retainer ring, the retainer ring has a portion having a large gap between the material to be polished and the retainer ring. Accumulation can be prevented by the above.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cutaway front view of the polishing apparatus according to the embodiment of the present invention.

FIG. 3 is a partially enlarged exploded perspective view of the polishing apparatus of FIG. 2;

FIG. 4 is a partially enlarged view of FIG. 2;

FIG. 5 is a view showing an example of the operation of the polishing apparatus of FIG. 4;

FIG. 6 is a view showing a state where the polishing apparatus of FIG. 3 is assembled.

FIG. 7 is a partially enlarged cutaway view of a conventional polishing apparatus.

FIG. 8 is a partially enlarged cutaway view of a conventional polishing apparatus.

FIG. 9 is a partially enlarged cutaway view of a conventional polishing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Holding base 2 Surface plate (polishing material pressing means) 3 Retainer ring 4 Wafer base (polishing material pressing means) 6 Retainer ring pressing part (Retainer ring pressing means) 7 Displacement control part 8 Back pressure channel 10 Lip seal 11 Wafer (Material to be polished) 12 Substantially closed space 13 Cleaning nozzle 15 Air flow path 16 Balloon-like elastic body 17 Holding plate 19 Connecting plate 20 Diaphragm 21 Polishing pad (abrasive) 24 Precision electronic regulator (polishing material pressing force control means) 25 Precision electronic regulator (Retainer ring pressing force control means) 26 Precision electronic regulator (Abrasive pressing force control means) 27 Balance controller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Katsuyoshi Shingu 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 3C058 AA12 AA14 AB04 BA05 BB04 CA01 CB02 CB03 DA17

Claims (19)

[Claims] 1. A disk-shaped material to be polished, one side of which is held by a holding member and whose periphery is surrounded by a retainer ring, is pressed against the abrasive, and the material to be polished is moved relative to the abrasive. A polishing apparatus that presses the material to be polished against the polishing material; retainer ring pressing means that presses the retainer ring against the polishing material; And abrasive material pressing means for pressing the retainer ring; abrasive material pressing force control means for controlling the pressure of the abrasive material pressing means for pressing the abrasive material; and the retainer ring of the retainer ring pressing means. A retainer ring pressing force control unit for controlling a pressing pressure; and an abrasive pressing force control unit for controlling a pressure of the abrasive pressing unit for pressing the abrasive. Polishing equipment. 2. The polishing apparatus according to claim 1, wherein said abrasive pressing means presses by a fluid pressure acting on a back surface of said abrasive. 3. The polishing apparatus according to claim 2, wherein the material-to-be-polished pressing means presses by a fluid pressure acting on a back surface of the material to be polished. 4. The polishing apparatus according to claim 2, wherein the retainer ring pressing unit presses the retainer ring by a fluid pressure acting on a back surface of the retainer ring. 5. The polishing material pressing force control means,
The polishing according to any one of claims 1 to 4, further comprising a pressing force balance control unit that balances respective pressures controlled by the retainer ring pressing force control unit and the abrasive material pressing force control unit. apparatus. 6. The abrasive pressing means presses the abrasive through a diaphragm.
A polishing apparatus according to claim 1. 7. The polishing apparatus according to claim 6, wherein an outer peripheral portion of the diaphragm is thicker than an inner side. 8. The polishing apparatus according to claim 3, wherein said polishing target pressing means has an annular lip seal on an outer peripheral portion of a back surface of said polishing target material. 9. The apparatus according to claim 1, wherein the holding member has a thin plate member attached in parallel to a polishing surface of the material to be polished, and the retainer ring is cantilevered by the plate member. 9. The polishing apparatus according to any one of items 1 to 8. 10. The plate member according to claim 9, wherein the plate member has a donut plate shape, and is supported by the holding member at an outer peripheral portion, and the retainer ring is cantilevered by an inner peripheral portion. Polishing equipment. 11. The retainer ring pressing means is made of an elastic body formed in a balloon shape, and injects the fluid into the elastic body to inflate the elastic body, thereby pressing the retainer ring. A polishing apparatus according to claim 1. 12. The polishing apparatus according to claim 11, wherein the elastic body has a donut shape. 13. A plurality of holes along the circumference are formed in an inner peripheral portion and an outer peripheral portion of the plate member, and concave and convex portions fitted through the holes are formed in the retainer ring and the holding member. ,
The polishing apparatus according to claim 10, wherein a hole of the plate member is held between the concave and convex portions. 14. A claw-shaped protruding portion that protrudes in the hole in a radial direction of the plate member, wherein the protruding portion includes:
14. The polishing apparatus according to claim 13, wherein the projection is elastically supported in a radial direction. 15. The convex portion of the retainer ring is supported from one of radially inner and outer sides of the opposing projecting portions, and the convex portion of the holding member is a direction in which the convex portion of the retainer ring is supported. The polishing apparatus according to claim 14, wherein the polishing apparatus is supported from a side opposite to the polishing apparatus. 16. The polishing apparatus according to claim 1, wherein the holding member is provided with a cleaning mechanism for discharging a fluid to an inner peripheral portion of the retainer ring to perform cleaning. 17. The polishing apparatus according to claim 16, wherein a step portion is provided on an inner peripheral portion of the retainer ring facing an outer peripheral surface of the workpiece. 18. An outflow passage for discharging a fluid used in the polishing target pressing means to the outside of the retainer ring is provided on a surface of the retainer ring facing the abrasive. The polishing apparatus according to any one of 3 to 17, 19. A disk-shaped material to be polished, one side of which is held by a holding member and whose periphery is surrounded by a retainer ring, is pressed against the abrasive, and the material to be polished is moved relative to the abrasive. In the polishing apparatus, the polishing object is pressed against the polishing material, the retainer ring is pressed against the polishing material, and the polishing material is pressed against the polishing target material and the retainer ring. Controlling the pressure for pressing the material, controlling the pressure for pressing the retainer ring, controlling the pressure for pressing the abrasive, and balancing the respective pressures for pressing the material to be polished, the retainer ring and the abrasive. A polishing method for polishing the material to be polished with the polishing material while controlling.