JP2013173225A - Polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing apparatus which can improve the use efficiency of slurry.SOLUTION: A polishing apparatus comprises: a machine platen 10 arranged with a polishing pad 12 at its upper face and rotatably driven; a substrate moving mechanism 30 for relatively moving a substrate W to the machine platen 10; and a slurry supply device for supplying slurry to the polishing pad by a nozzle 63, and performs polishing processing while supplying the slurry. The polishing apparatus also comprises a slurry receiving groove 110 for receiving the slurry poured out of the polishing pad 12, and a liquid sending pump 150 for making the slurry received by the slurry receiving groove 110 flow out to the center of the upper face of the polishing pad 12 via a slurry collecting passage 130 and a slurry supply passage 120. The polishing apparatus is constituted so that the slurry may circulate in the machine platen 10 during the polishing processing of the substrate W.

Description

The present invention relates to a polishing apparatus for polishing a substrate by relatively moving a surface plate and a substrate in the presence of slurry.

As a polishing apparatus as described above, a CMP apparatus (Chemical Mechanical Polishing Machine) that polishes the surface of a silicon substrate, a glass substrate or the like flatly is widely known. CMP
The apparatus includes, for example, a surface plate provided with a polishing pad on the upper surface and driven to rotate about a rotating shaft extending downward, a substrate moving mechanism for moving the substrate while the substrate is in contact with the polishing pad, and the polishing pad A slurry supply device for supplying slurry to the upper surface of the substrate, supplying the slurry from the slurry supply device to the upper surface of the polishing pad, and relatively moving the surface plate and the substrate in the presence of the slurry to polish the substrate surface flatly Configured to do.

Here, the slurry supplied to the upper surface of the pad from the slurry supply device is moved from the center to the outer periphery by the centrifugal force accompanying the rotation of the surface plate, and flows down from the outer peripheral edge of the polishing pad and is removed from the surface plate. Is done. Therefore, some of the slurries supplied from the slurries supply apparatus do not contribute to the polishing process, and simply flow over the top surface of the polishing pad and are excluded as they are. Of the slurries supplied to the polishing pad, It is said that the ratio of the slurry that contributes to the polishing process, that is, the utilization efficiency of the slurry is generally less than 10%. Therefore, a polishing apparatus provided with a circulation system that collects the slurry that has flowed down from the surface plate, returns it to a tank in which unused slurry (referred to as fresh slurry) is stored, and supplies the slurry again to the polishing pad by a pump of the slurry supply apparatus. It has been devised (for example, see Patent Document 1).

US Pat. No. 6,159,082

However, the conventional polishing apparatus as described above has a complicated structure for collecting and circulating the slurry supplied onto the polishing pad, and there is a problem that the entire polishing apparatus is increased in size. The present invention has been made in view of the above problems, and an object thereof is to provide a polishing apparatus capable of improving the utilization efficiency of slurry without complicating and increasing the size of the apparatus.

In order to achieve the above object, the present invention provides a surface plate provided with a polishing pad on the upper surface and driven to rotate about a rotating shaft extending downward, and a substrate with respect to the surface plate in a state where the substrate is in contact with the upper surface of the polishing pad. A substrate moving mechanism (for example, the substrate carrier 20, the carrier moving mechanism 30 and the like in the embodiment), and a slurry supply device for supplying the slurry to the upper surface of the polishing pad, and the relative relationship between the surface plate and the substrate in the presence of the slurry. In the polishing apparatus configured to polish the substrate by movement, the surface plate has a slurry receiving groove for receiving the slurry spilled on the outer peripheral side of the polishing pad, and an opening in the center of the upper surface of the surface plate. A slurry supply path extending downwardly,
A slurry recovery path formed by connecting the slurry receiving groove and the slurry supply path, and a liquid feeding means for discharging the slurry received in the slurry receiving groove from the opening through the slurry recovery path and the slurry supply path (for example, in the embodiment) A liquid feed pump 150), and the slurry received in the slurry receiving groove is supplied from the opening to the upper surface of the polishing pad by the liquid feed means during the polishing of the substrate, and the slurry is circulated on the surface plate. The

According to the present invention, there is provided a polishing apparatus in which the slurry received in the slurry receiving groove is circulated in the surface plate so that the utilization efficiency of the slurry is improved without complicating and increasing the size of the apparatus configuration. be able to.

It is a sectional side view which shows the schematic structure of a slurry circulation mechanism. It is a top view of the said surface plate. It is the sectional side view to which the part of the slurry receiving groove shown in FIG. 1 was expanded. The flow rate Q _{1 of} the slurry supplied to the upper surface of the polishing pad by the slurry supply device, the flow rate Q _{2 of} slurry supplied to the upper surface of the polishing pad by the liquid feed pump, and the total supply amount Q _all to the upper surface of the polishing pad obtained by adding them It is a graph of the 1st embodiment showing relation. It is a graph of a second embodiment representing the relationship of the flow rate Q _1, Q _2, Q _all of the slurry. It is a graph of a third embodiment which represents the relationship of the flow rate Q _1, Q _2, Q _all of the slurry. It is a sectional side view which shows the other structural example of a slurry receiving groove. It is drawing which shows schematic structure of the grinding | polishing apparatus to which this invention is applied.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 8 shows a schematic configuration (side view) of the polishing apparatus 1 to which the present invention is applied. The polishing apparatus 1 is driven to rotate by a surface plate 10 provided with a polishing pad 12 on the upper surface and rotated around a spindle extending downward, and a substrate W such as a glass substrate, silicon substrate, or semiconductor wafer on the lower surface. A carrier moving mechanism 30 that has a substrate carrier 20 and presses the held substrate W against the polishing pad 12 and swings horizontally, a slurry supply device 60 that supplies slurry to the surface plate 10 during polishing, and the like. .

The operation of each part of the polishing apparatus 1 is controlled by the control device 80, and slurry is supplied to the upper surface of the polishing pad 12, and the surface plate 10 and the substrate carrier 20 are rotated relative to each other to bring the substrate W into contact with the polishing pad 12. Under pressure, the substrate W and the polishing pad 12 are relatively moved (rotation and swing of the substrate carrier 20 and rotation of the surface plate 10) in the presence of the slurry to polish the substrate surface flatly. The polishing apparatus 1 is provided with a dressing mechanism 70 for dressing the surface of the polishing pad by bringing a dressing tool 72 to which diamond abrasive grains or the like are fixed into contact with the polishing pad.

The surface plate 10 as a whole has a thick disk-shaped pad surface plate 11 larger in diameter than the substrate W to be processed, and a polishing pad 12 mounted on the upper surface of the pad surface plate 11 by means such as adhesion or adhesion. And a spindle 13 that extends vertically downward from the pad surface plate 11 and transmits a rotational driving force to the pad surface plate, and the upper surface 12u of the polishing pad 12 is disposed in an upward horizontal posture.

A carrier moving mechanism 30 is provided adjacent to the surface plate 10, and a substrate carrier 20 is provided at the tip thereof.
Is provided. The substrate carrier 20 includes, for example, a disc-shaped chuck 21 that detachably holds the substrate W by vacuum suction, a pressurizing mechanism that presses the substrate held by the chuck 21 against the polishing pad 12, and a rotational driving force to the chuck 21. The substrate W is disposed facing the polishing pad 12 in a downward horizontal posture. The carrier moving mechanism 30 has an arm 31 that can be horizontally swung with respect to the surface plate 10, and the substrate carrier 20 is provided on a spindle holder that protrudes downward from the tip of the arm 31.

The slurry supply device 60 stores various types of substrate polishing slurry and cleaning pure water (rinse liquid) according to the processing target, and supplies the slurry and the like based on a command signal from the control device 80. A supply unit 61 and a line 62 that is a piping path for guiding the slurry and the like sent from the slurry supply unit 61 to the surface plate 10 are provided. Line 6
The nozzle 6 is extended to the vicinity of the rotation center of the surface plate 10 and the supply position can be adjusted.
3 is provided, and the unused slurry sent from the slurry supply unit 61 (
Fresh slurry) is supplied from above the polishing pad 12.

On the other hand, the surface plate 10 is provided with a slurry circulation mechanism 100 for circulating the slurry in the surface plate. FIG. 1 shows a schematic configuration diagram (side sectional view taken along the line I-I in FIG. 2) of the slurry circulation mechanism 100 cut along a vertical plane passing through the rotation axis of the surface plate 10, and FIG. The figure is shown. The slurry circulation mechanism 100 is located on the outer peripheral side of the surface plate 10, and receives a slurry spilled from the polishing pad 12 to the outer peripheral side, and a discharge opening 12 in the center of the upper surface of the surface plate 10.
1, a slurry supply path 120 extending downward, a slurry collection path 130 formed by connecting the slurry receiving groove 110 and the slurry supply path 120, and the slurry received by the slurry receiving groove 110 and the slurry collection path 130 and Discharge opening 12 through slurry supply path 120
1 and a liquid feed pump 150 that flows out from the substrate 1, and during the polishing of the substrate W, the slurry receiving groove 1
10 is supplied to the upper surface 12u of the polishing pad 12 from the discharge opening 121 by the liquid feed pump 150, and the slurry is circulated on the surface plate 10.

As shown in FIG. 3, the slurry receiving groove 110 shown in this embodiment is an enlarged side sectional view of the slurry receiving groove 110, and the outer peripheral surface 12 a of the polishing pad 12 mounted on the upper surface of the pad surface plate 11. A cylindrical scattering prevention ring 140 provided around the outer periphery of the pad surface plate 11.
The inner circumferential surface 140a and the upper surface 11u of the pad surface plate 11 exposed between the inner circumferential surface 140a are formed in an annular shape in a plan view and a concave groove shape in a side sectional view.

The scattering prevention ring 140 is provided so as to be movable up and down with respect to the pad surface plate 11 by a ring lifting mechanism (not shown), and the upper end 140 u of the scattering prevention ring 140 is positioned above the upper surface 12 u of the polishing pad 12. And a second position lower than the upper surface 12u of the polishing pad. The first position P ₁ and the second position of the anti-scattering ring 140
Although the position P ₂ (P ₂₁ , P ₂₂ ) will be described in detail later, when the substrate W is polished, the anti-scattering ring 140 is disposed at the first position P ₁ , and the slurry receiving groove extends from the outer peripheral end of the polishing pad 12. 1
In addition to the slurry that flows down to 10, the slurry that scatters horizontally from the outer peripheral end of the polishing pad 12 by centrifugal force is received by the inner peripheral surface 140 a of the anti-scattering ring 140 and flows into the slurry receiving groove 110. . Further, when the cleaning liquid is supplied to the upper surface of the polishing pad to rinse the substrate and when the polishing pad 12 is dressed, the anti-scattering ring 140 is disposed at the second position.

The slurry supply path 120 has a discharge opening 121 formed through the polishing pad 12 at the center of the upper surface of the surface plate 10, and is formed to extend downward to the pad surface plate 11 connected to the discharge opening 121. ing. Inside the pad surface plate 11, a slurry collection path 130 that connects the slurry receiving groove 110 and the slurry supply path 120 is provided. The slurry recovery path 130 is a circular hole-shaped slurry introduction hole 131 that extends downward from the bottom surface of the annular groove-shaped slurry receiving groove 110 and a circular hole-like shape that connects the slurry introduction hole 131 and the central slurry supply path 120. In this embodiment, a configuration example in which a plurality (six in FIG. 2) of slurry collection paths 130 are provided radially on the pad surface plate 11 is shown. The slurry collection path 130
For example, a circular hole is drilled from the outer peripheral end surface of the pad surface plate 11 toward the center, the slurry introduction hole 131 and the slurry supply passage 120 are communicated, and then the opening of the outer peripheral end surface is closed with a plug or the like. It can be configured, or can be formed in the form shown in the figure without providing a plug on the outer peripheral end surface by lost wax casting or the like.

The liquid feed pump 150 is located in the center of the surface plate 10 and is provided at a connecting portion between the slurry supply path 120 and the slurry recovery path 130. The liquid supply pump 150 sucks the slurry flowing into the slurry recovery path 130 and sucks the slurry supply path 120. And is discharged upward from the discharge opening 121 (that is, from the lower side of the polishing pad 12) and supplied to the center of the upper surface of the polishing pad 12. Liquid feed pump 15
0 is provided with a flow meter for detecting the discharge flow rate of the pump, and a detection signal of the flow meter is input to the control device 80 via a rotary joint provided on the spindle 13, and the control device 80 is connected to the rotary joint. Rotation control of the pump motor is performed via A filter 155 is provided between the discharge port of the liquid feed pump 150 and the discharge opening 121 to remove a broken piece of the polishing pad generated by dressing, diamond abrasive grains dropped from the dressing tool 72, aggregated particles of slurry, and the like. ing.

Below the liquid feed pump 150, the upper end is connected to the slurry recovery path 130 and extends downward,
A slurry discharge path 160 is formed on the other end side of the spindle 13 and led out to the outside, and a discharge path opening / closing valve 165 for opening and closing the slurry discharge path 160 is provided.

Next, the operation of the polishing apparatus 1 configured as described above will be described. First, at the time of polishing, the surface plate 10 and the substrate carrier 20 are rotationally driven, and the substrate W held by the substrate carrier 20 is moved above the surface plate 10 by the carrier moving mechanism 30 and pressed against the polishing pad 12. And is swung left and right under predetermined conditions. At this time, in the slurry supply device 60, the slurry of the type set in the processing conditions is supplied at the flow rate based on the setting.
And is supplied from above the surface plate 10 to the vicinity of the center of the upper surface of the polishing pad 12 via the line 62 and the nozzle 63. Further, the anti-scattering ring 140 provided on the surface plate 10 is set at a first position P ₁ whose upper end 140 u is higher than the upper surface 12 u of the polishing pad.

The slurry supplied to the vicinity of the center of the upper surface of the polishing pad 12 moves on the upper surface 12u of the polishing pad in the outer peripheral direction by the centrifugal force accompanying the rotation of the surface plate 10, and 5 to 10% in the moving process.
A certain amount of slurry is interposed in the sliding contact portion between the substrate W and the polishing pad 12 to polish the substrate (CMP
Processing). Thus, the slurry that has contributed to the polishing process and the slurry that has moved on the upper surface 12u of the polishing pad without contributing to the polishing process, the viscosity of the slurry to be used, the supply flow rate per unit time, the rotational speed of the surface plate 10, the polishing pad 12 It reaches the outer peripheral edge of the polishing pad 12 in a predetermined time roughly determined according to the properties and the like, and finally flows down from the outer peripheral edge of the polishing pad 12 and flows into the slurry receiving groove 110.

Here, at the time of polishing the substrate W, the scattering prevention ring 140 is set to the first position P _{1 in} which the upper end 140u of the ring is higher than the upper surface 12u of the polishing pad. Therefore, for example, even when the peripheral speed of the polishing pad outer peripheral edge accompanying the rotation of the surface plate 10 is large and much of the slurry that has reached the outer peripheral edge of the polishing pad 12 is scattered horizontally by centrifugal force, it is scattered. The slurry is received by the inner wall surface 140a of the anti-scattering ring and flows into the slurry receiving groove 110. Therefore, the slurry can always be recovered with a high probability regardless of the rotation speed of the platen, the viscosity of the slurry, etc. (processing conditions).

The slurry that has flowed into the slurry receiving groove 110 gradually fills the slurry receiving groove 110 and flows into the slurry collection path 130 from the slurry introduction hole 131 formed in the groove bottom surface (11u). When the slurry closes the plurality of formed slurry introduction holes 131, 131..., The suction force of the liquid feed pump 150 acting on the slurry in each slurry recovery path 130 increases,
The slurry sucked up through the slurry collecting paths 132, 132...
The slurry is discharged from the slurry supply path 120 and filtered by the filter 155, and the discharge opening 1
21 flows out to the center of the top surface of the polishing pad 12

Slurry that flows out from the discharge opening 121 to the center of the upper surface of the polishing pad 12 (referred to as circulating slurry) again flows in the outer circumferential direction on the upper surface 12u of the polishing pad by the centrifugal force accompanying the rotation of the surface plate 10, and a certain percentage of slurry is polished After contributing to the processing, the slurry flows into the slurry receiving groove 110 from the outer peripheral end of the polishing pad 12. As described above, in the slurry circulation mechanism 100, the slurry supplied from the slurry supply device 60 circulates through a short path in the surface plate 10 and moves on the upper surface of the polishing pad 12 a plurality of times. Therefore, it is difficult to be affected by changes in the properties of the slurry, mixing of impurities, and the like, and the contribution ratio of the slurry that contributes to the polishing process can be increased.

By the way, when the rotation speed of the liquid feed pump 150 is made constant, the slurry receiving groove 110 is filled to a certain extent with the slurry (until all the slurry introduction holes 131, 131... Are closed with the slurry). When the flow rate of the slurry returning from the discharge opening 121 to the upper surface of the polishing pad 12 increases and the slurry receiving groove 110 is filled with the slurry over the entire circumference, the flow rate of the circulating slurry is quantified. Thus, a predetermined time is required from the start of the supply of the fresh slurry by the slurry supply device 60 to the start of the supply of the circulating slurry by the slurry circulation mechanism 100, and thereafter the supply amount of the circulating slurry is quantified. It takes another predetermined time. As described above, the predetermined time and the like vary depending on the type and flow rate of the slurry to be used, the rotational speed of the surface plate 10, and the like. When the flow rate of the slurry flowing on the upper surface of the polishing pad 12 changes, the processing conditions for the polishing process change.

Therefore, the polishing apparatus 1 is configured such that the flow rate of the slurry flowing on the upper surface of the polishing pad 12 is substantially constant. That is, in the polishing apparatus 1, the slurry flow rate (supply amount per unit time) Q ₁ supplied to the upper surface of the polishing pad 12 by the slurry supply device 60 and the upper surface of the polishing pad 12 are supplied by the liquid feed pump 150. The supply amount Q of slurry by the slurry supply device 60 so that the total supply amount Q _all = Q ₁ + Q ₂ to the upper surface of the polishing pad, which is the sum of the flow rate of slurry (supply amount per unit time) Q ₂ , is substantially constant. ₁ is controlled.

A graph illustrating this relationship is shown in FIG. In this graph, the vertical axis represents the polishing pad 12.
The supply amount Q per unit time of the slurry supplied to the upper surface of, and the horizontal axis is time t. As shown in the drawing, in the initial state from time t ₀ to time t ₁ when the surface plate 10 starts to rotate and the supply of fresh slurry by the slurry supply device 60 starts, the slurry moves on the polishing pad in the outer circumferential direction. The supply of the circulating slurry by the slurry circulating mechanism 100 has not started. Therefore, the slurry supplied to the upper surface of the polishing pad 12 in this initial state is only the fresh slurry supplied by the slurry supply device 60, and the unit time of the slurry sent from the slurry supply unit 61 to the upper surface of the polishing pad 12 The per-supply amount Q ₁ is kept constant.

After the time t ₁ when a predetermined time has elapsed after the supply of fresh slurry by the slurry supply device 60 is started, the initially supplied slurry moves to the outer peripheral end on the polishing pad and begins to accumulate in the slurry receiving groove 110. The supply amount Q ₂ of the circulating slurry per unit time by the liquid feed pump 150 gradually increases (time t ₁ → t ₂ ). Therefore, from time t ₁ to time t
The supply amount Q per unit time of the slurry supplied to the upper surface of the polishing pad 12 in the intermediate state of ₂ is the supply amount Q ₁ per unit time of the fresh slurry supplied from the slurry supply unit 61 and the liquid feed pump 150 is the total value of the supply amount Q ₂ of the circulating slurry discharged from 150 per unit time.

Here, the supply amount Q ₁ per unit time of the slurry supplied from the slurry supply unit 61 is controlled by a control value output from the control device 80 based on the processing conditions, and is known. Further, the supply amount Q ₂ per unit time of the circulating slurry discharged from the liquid feed pump 150 is grasped by a detection signal input to the control device 80 from a flow meter attached to the liquid feed pump 150. Therefore, the controller 80 decreases the fresh slurry supply flow rate Q ₁ sent from the slurry supply unit 61 as the circulating slurry flow rate Q ₂ input from the flow meter of the liquid feed pump 150 increases. Then, the slurry supply device 60 is controlled so that the total supply amount Q _all = Q ₁ + Q ₂ supplied to the upper surface of the polishing pad 12 becomes substantially constant.

Then, after time t ₂ when a predetermined time has elapsed since the supply of the circulating slurry by the slurry circulating mechanism 100 has started, the supply amount Q _{2 of the} circulating slurry discharged from the liquid feed pump 150 per unit time is the liquid feed pump. Stable at the flow rate set for 150. In the embodiment shown in FIG. 4, the flow rate Q ₂ of the liquid feed pump 150 at the time of stability is the same as the flow rate Q ₁ of the slurry supply unit 61 in the initial state (Q ₂ = Q ₁ ). The pump speed is set. Therefore, in the later state at the time t ₂ after which the flow rate Q ₂ is stable in liquid feed pump 150, a slurry supply from the slurry supply unit 61 is stopped, polishing of the substrate W by the circulating slurry is circulated by slurry circulating mechanism 100 Is done. As a result, the amount of fresh slurry used can be reduced, and the contribution ratio of the slurry contributing to the polishing process can be further increased.

As is clear from the above description, the flow rate of the circulating slurry by the liquid feed pump 150 can be appropriately changed and set. 5 and 6 are configuration examples in which the supply state of the slurry supplied to the upper surface of the polishing pad 12 is set differently from the embodiment shown in FIG. 4 by controlling the operation of the liquid feed pump 150.

First, in the embodiment shown in FIG. 5, the liquid feed pump 150 is rotationally activated at time t ₁₁ when the above-described time t ₁ has elapsed. That is, a predetermined time elapses after the supply of fresh slurry by the slurry supply device 60 is started, and the slurry supplied in the initial stage is the slurry receiving groove 110.
The liquid feed pump 150 is started to rotate when it starts to accumulate to some extent. The pump rotation in the rotation startup time t ₁₁ is the low speed, and the pump speed gradually increased to the time t ₁₂ (time t ₁₁ → t _12), the time t ₁₂ per unit of circulating slurry time later The supply amount Q ₂ is controlled to be the same as the initial flow rate of fresh slurry by the slurry supply device 60. According to such a configuration, the supply capacity of fresh slurry can be secured, invalid power consumption can be reduced, and the feed pump 150 can be stably pumped.

The embodiment shown in FIG. 6 is similar to the embodiment shown in FIG. 5 at time t ₂₁ when time t ₁ has elapsed.
The liquid feed pump 150 starts rotating at a low speed, and the pump speed is increased to a specified speed at an arbitrary time until time t ₂₂ (time t ₂₁ → t ₂₂ ). After time t ₂₂ , the speed is constant at a specified speed. Driven.
The discharge flow rate of the liquid feed pump 150 at the specified rotational speed, that is, the supply amount Q ₂ per unit time of the circulating slurry after time t ₂₂ is lower than the initial flow rate of fresh slurry by the slurry supply device 60, for example, 70 to It is set to about 90%. Therefore, the slurry feed is continued from the slurry supply unit 61 after time t _22, polishing of the substrate W is carried out by the circulating slurry and fresh slurry in a polishing part. According to such a configuration, polishing can always be performed in the presence of fresh slurry, and the constituent ratio of fresh slurry to circulating slurry can be set appropriately.

When the polishing process of the substrate W is executed as described above and the polishing process is completed, rinsing cleaning for removing the slurry attached to the substrate W is performed next. The rinse cleaning is performed by supplying a cleaning liquid (rinsing liquid) such as pure water from the slurry supply device 60 to the surface plate 10. Specifically, the cleaning liquid is supplied from the slurry supply unit 61 to the center of the upper surface of the polishing pad 12 via the line 62 and the nozzle 63, and the substrate W and the polishing pad 12 are moved relative to each other while supplying the cleaning liquid. The slurry adhering to W and the slurry in the surface plate including the polishing pad 12 are washed away.

In the polishing apparatus 1, when performing the rinse cleaning, the scattering prevention ring 140 provided on the outer peripheral side of the surface plate 10 is set at a second position where the upper end 140 u is lower than the upper surface 12 u of the polishing pad 12. The second position can be appropriately set as long as the ring upper end 140u is at a height position lower than the upper surface 12u of the polishing pad, and a plurality of second positions can be set. Therefore, first, in the surface plate 10 shown in FIG. 3, the second position is lower than the upper surface 12u of the polishing pad 12 and higher than the upper surface 11u of the pad surface plate 11, and the pad upper surface 12u and the pad surface surface 11u.
A case will be described in which the height is set to the middle position (the second position P ₂ indicated by a two-dot chain line in FIG. 3) of (the lower surface of the polishing pad).

When the anti-scattering ring 140 is set to the second position P ₂ and rinse cleaning is started, the cleaning liquid supplied to the vicinity of the center of the upper surface of the polishing pad 12 is subjected to the centrifugal force accompanying the rotation of the surface plate 10 and the upper surface of the polishing pad. 12u flows in the outer circumferential direction, and the slurry remaining on the upper surface 12u of the polishing pad is pushed away in the outer circumferential direction. At this time, the slurry adhering to the lower surface of the substrate W is washed away by the relative movement of the substrate and the polishing pad, and flows along the pad periphery together with the cleaning liquid. A cleaning liquid (referred to as cleaning liquid or the like) containing slurry reaches the outer peripheral edge of the polishing pad 12, and a part of the cleaning liquid is scattered horizontally from the outer peripheral edge of the polishing pad and discharged from the surface plate 10.

On the other hand, the cleaning liquid or the like flowing down from the outer peripheral end of the polishing pad 12 and flowing into the slurry receiving groove 110 overflows from the slurry receiving groove 110 with the increase of the flowing cleaning liquid or the like, and climbs over the upper end of the anti-scattering ring 140. 10 is discharged. At this time, the second position P ₂ where shatterproof ring 140 is disposed, since the upper end 140u of the scattering prevention ring is set at a height position lower than the upper surface 12u of the polishing pad, overflowing washing liquid or the like Polishing pad 12
There is no such thing as covering the top surface.

Further, at the time of rinsing, the discharge passage opening / closing valve 165 built in the surface plate 10 is opened, the upper end is connected to the slurry recovery passage 130, and the other end side is released from the slurry discharge passage 160 to the outside. The For this reason, the cleaning liquid or the like flowing into the slurry receiving groove 110 flows down the slurry discharge passage 160 while washing away the slurry remaining in the slurry collection passage 130 and is discharged from the surface plate 10 to the outside. As a result, the slurry receiving groove 110 and the slurry collection path 1
No slurry remains or solidifies at 30.

In addition, a pump (discharge pump) similar to the liquid feed pump 150 is provided in the slurry discharge path 160, and the discharge pump is driven during the rinse cleaning so that the cleaning liquid or the like located in the slurry recovery path 130 is sucked and discharged. It is also preferable to configure. According to such a configuration, the slurry remaining in the slurry collection path 130 can be forcibly sucked and discharged more effectively without being affected by the centrifugal force accompanying the rotation of the surface plate 10. .

In the above, the case where the substrate W is rinsed with the cleaning liquid has been described. However, the same configuration can be applied to the case where the polishing pad 12 is dressed by the dressing mechanism 70. Therefore, hereinafter, the operation when dressing the polishing pad 12 will be briefly described. For dressing, a cleaning liquid such as pure water is supplied from the slurry supply unit 61 to the center of the upper surface of the polishing pad 12 through the line 62 and the nozzle 63, and the dressing tool 72 that is in contact with the upper surface 12u of the polishing pad is rotated. By swinging or reciprocating in the radial direction, the polishing pad 12 and the dressing tool 72 are moved relative to each other, and the upper surface 12u of the polishing pad is dressed up flat.

In the polishing apparatus 1, the scattering prevention ring 140 is set to the second position also when performing dressing. Here, FIG. 7 shows another configuration example of the slurry receiving groove. FIG. 7 is an enlarged side cross-sectional view of the slurry receiving groove as in FIG. The slurry receiving groove 210 has an annular step formed by cutting the outer peripheral edge of the pad surface plate 11 lower than the central portion, and surrounds the outer peripheral surface 210a and the bottom surface 210b of the annular step. Inner circumferential surface 1 of the scattering prevention ring 140
40a, the annular groove-shaped slurry receiving groove 210 is formed. According to such a configuration, the slurry collection path 130 can be formed easily and at low cost.

In the present embodiment, a description will be given of a case where the second position is set at two locations, an upper second position P ₂₁ and a lower second position P ₂₂ , both indicated by a two-dot chain line in FIG. Here, the upper second position P ₂₁ is
The upper end of the step (upper surface 11u of the pad plate 11) substantially the same height, the lower second position P ₂₂ is set somewhat lower than the lower end of the step (the bottom 210b of the slurry recovery groove 210).

First, at the beginning of dressing, scattering prevention ring 140 is set to a second upper position P _21. The cleaning liquid supplied to the center of the upper surface of the polishing pad 12 flows in the outer peripheral direction due to the centrifugal force accompanying the rotation of the surface plate 10, broken pieces of the polishing pad scraped off by dressing, diamond abrasive grains dropped from the dressing tool 72, etc. To the outer circumferential direction. A cleaning liquid containing these foreign substances (also referred to as a cleaning liquid or the like) reaches the outer peripheral edge of the polishing pad 12, and a part of the cleaning liquid is scattered horizontally from the outer peripheral edge of the polishing pad and discharged from the surface plate 10.

The cleaning liquid or the like that has flowed into the slurry receiving groove 210 from the outer peripheral end of the polishing pad 12 fills the slurry receiving groove 210 with the increase of the flowing-down cleaning liquid or the like, and finally gets over the upper end of the anti-scattering ring 140 from the surface plate 10. Discharged. In second upper position P _21, since the upper end 140u of the scattering prevention ring is set to be substantially the same height as the upper surface of the pad plate 11u (lower surface of the polishing pad), the cleaning liquid or the like which has flowed into the slurry receiving groove 210 again There is no return to the upper surface side of the polishing pad 12. Further, also during dressing, the discharge passage opening / closing valve 165 built in the surface plate 10 is opened, and the slurry discharge passage 160 is opened. For this reason, the cleaning liquid containing foreign matter such as broken pieces of the polishing pad and diamond abrasive grains flowing into the slurry receiving groove 210 flows down the slurry discharge path 160 and is discharged from the surface plate 10 to the outside. According to the configuration in which a discharge pump similar to the liquid feed pump 150 is provided in the slurry discharge path 160, and the discharge liquid is sucked and discharged in the slurry recovery path 130 by operating the discharge pump during dressing. Without being affected by the centrifugal force associated with the rotation of the panel 10, the cleaning liquid containing foreign substances can be discharged more effectively.

The end of dressing a predetermined time has elapsed the start of the dressing, scattering prevention ring 140 is set to the lower second position P _22. When scattering prevention ring 140 is set to the lower second position P _22, the slurry-receiving channel 210 is opened the side of the outer peripheral side becomes stepped state, the cleaning liquid or the like flowing down from the outer peripheral edge of the polishing pad 12 is stepped outer periphery It flows through the surface 210a and the bottom surface 210b, and is discharged from the surface plate 10 so as to wash away the slurry receiving groove. For this reason, it is possible to wash away diamond abrasive grains and pad shavings that are likely to remain at the bottom of the groove and discharge them from the surface plate 10.

In the above, the case where the polishing pad 12 is dressed has been described as an example. However, the present invention can be similarly applied to the case where the substrate W is rinsed, and thereby, the diamond abrasive grains which tend to remain at the bottom of the slurry receiving groove. It is possible to clean away the pad scraps and the like, and discharge them from the surface plate 10.

Therefore, according to the polishing apparatus as described above, the overall configuration of the polishing apparatus is complicated,
The utilization efficiency of the slurry can be improved without increasing the size.

W substrate P ₁ first position P ₂ , P ₂₁ , P ₂₂ second position 1 polishing apparatus 10 surface plate 12 polishing pad 20 substrate carrier (substrate moving mechanism)
30 Carrier movement mechanism (substrate movement mechanism)
60 Slurry supply device 70 Dress mechanism 72 Dress tool 110, 210 Slurry receiving groove 120 Slurry supply path 130 Slurry recovery path 140 Anti-scattering ring (enclosure)
150 Liquid feed pump (liquid feed means)
160 Slurry discharge passage 165 Drain passage opening / closing valve (discharge passage opening / closing means)

Claims (1)

A surface plate provided with a polishing pad on the upper surface and driven to rotate about a rotation axis extending downward; a substrate moving mechanism for moving the substrate relative to the surface plate in a state where the substrate is in contact with the upper surface of the polishing pad; And a polishing apparatus configured to perform polishing of the substrate by relative movement between the surface plate and the substrate in the presence of slurry, comprising a slurry supply device that supplies slurry to the upper surface of the polishing pad.
On the surface plate,
A slurry receiving groove for receiving slurry spilled on the outer peripheral side of the polishing pad;
A slurry supply path extending downward with an opening in the center of the upper surface of the surface plate;
A slurry recovery path formed by connecting the slurry receiving groove and the slurry supply path;
A liquid feeding means for causing the slurry received in the slurry receiving groove to flow out of the opening through the slurry recovery path and the slurry supply path;
During polishing of the substrate, the slurry received in the slurry receiving groove is supplied from the opening to the upper surface of the polishing pad by the liquid feeding means, and the slurry is circulated on the surface plate. Polishing equipment.

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