TW201801853A - Substrate polishing method, top ring, and substrate polishing apparatus - Google Patents

Abstract

The present invention provides a substrate polishing method, a substrate polishing apparatus, and a top ring for a substrate polishing apparatus capable of appropriately processing a substrate.The present invention provides a substrate polishing method comprising the steps of: a conveyance step (S2) in which a substrate is fed to a polishing pad by a first region of a flexible film; a grinding step (S4) in which the substrate is brought into contact with the polishing pad to grind the substrate in the polishing step (S4); and a lift-off step (S6) in which the substrate is lifted from the polishing pad by sucking the substrate by a second region wider than the first region of the elastic film in the lift step (S6) from.

Description

Method for polishing substrate, top ring and substrate polishing device

The present invention relates to a substrate polishing method for polishing a substrate, a top ring holding a substrate, and a substrate polishing apparatus including such a top ring.

A general substrate polishing apparatus uses a top ring that holds a substrate, and polishes the substrate in the following procedure. First, the top ring receives a substrate from a transfer device, and transfers the substrate to a polishing pad. Next, the top ring holding the substrate is lowered, and the substrate is in contact with the polishing pad. In this state, the top ring rotates the substrate and polishes the substrate while supplying a polishing liquid. When the polishing is completed, an operation called lift off is performed, which lifts the substrate away from the polishing surface of the polishing pad by raising the top ring, and lifts the substrate (for example, Patent Document 1, 2). In addition, the top ring passes through a membrane that vacuum-absorbs the substrate on the lower surface of the top ring to hold or lift the substrate away.

Prior art literature

Patent literature

Patent Document 1: Japanese Patent No. 5390807

Patent Document 2: Japanese Patent Application Laid-Open No. 2009-178800

In Patent Document 1, vacuum suction is performed to the same extent when the substrate is carried on a polishing pad or when the substrate is lifted off. However, if the vacuum suction is too strong, When the substrate is transferred to the polishing pad, a pressure is applied to the substrate and the substrate may be damaged. Conversely, if the vacuum suction force is too weak, the substrate may crack and fail to be picked up when the substrate is lifted off. This is because a polishing liquid is present between the substrate and the polishing pad, and surface tension is generated between the substrate and the polishing pad after polishing.

In contrast, Patent Document 2 discloses that the vacuum degree is increased at the time of lift-off compared to when the substrate is carried on a polishing pad. However, it does not necessarily increase the vacuum degree of the entire diaphragm, so it may not be able to be lifted off reliably.

The present invention has been made in view of such problems, and it is a problem of the present invention to provide a substrate polishing method, a substrate polishing apparatus, and a top ring for such a substrate polishing apparatus, which can appropriately process a substrate.

According to one aspect of the present invention, there is provided a substrate polishing method including the following steps: a transporting step in which a substrate is adsorbed by a first region of an elastic film and the substrate is transported to a polishing pad; A polishing step in which the substrate is brought into contact with the polishing pad and the substrate is polished; and a lift-off step in which the ratio of the elastic film to the first is used The second region having a wide area attracts the substrate and lifts the substrate away from the polishing pad.

Since the substrate is sucked in a narrow area when the substrate is transferred to the polishing pad, the pressure applied to the substrate can be reduced. In addition, since the substrate is adsorbed by a wide area when the substrate is lifted off, the substrate can be reliably lifted off.

According to another aspect of the present invention, there can be provided a substrate polishing method including the following steps: a transportation step in which a region capable of adjusting a pressure formed between a top ring body and an elastic film can be adjusted ( area), the first area is decompressed, so that the substrate is adsorbed on the lower surface of the elastic film and the substrate is carried on a polishing pad; in the polishing step, the substrate is brought into contact with the polishing pad And polishing the substrate; and a lift-off step in which a second region wider than the first region in the region where the pressure can be adjusted is decompressed to utilize the elasticity The lower surface of the film adsorbs the substrate and lifts the substrate away from the polishing pad.

When the substrate is transferred to the polishing pad, the pressure is applied to the substrate by reducing the pressure in a narrow area to attract the substrate. In addition, when the substrate is lifted off, a wide area is decompressed and the substrate is adsorbed. Therefore, the substrate can be reliably lifted off.

Alternatively, a plurality of regions capable of adjusting pressure can be formed between the top ring main body and the elastic membrane, the first region includes a predetermined number of regions among the plurality of regions, and the second region Including the plurality of regions has a larger number of regions than the prescribed number.

This makes it possible to make the second region wider than the first region.

In the polishing step, at least a part of the region where the pressure can be adjusted may be pressurized.

In this case, since the area to be decompressed before grinding is narrow, it is possible to quickly pressurize to a desired pressure during grinding.

It is desirable that a support portion extending toward the elastic film is provided in an area where the pressure can be adjusted.

By providing a support portion, even if a wide area is used for adsorption during lifting, the shape change of the elastic film is small, and the pressure on the substrate can be reduced.

According to an aspect of the present invention, a top ring for holding a substrate may be provided. The top ring includes: a top ring body; and an elastic film, the elastic film is disposed below the top ring body, and the elastic film and A region where pressure can be adjusted is formed between the top ring bodies; and a support portion is provided in the region and extends toward the elastic membrane.

By providing a support portion, even if a wide area is used for adsorption during lifting, the shape change of the elastic film is small, and the pressure on the substrate can be reduced.

It is desirable to include a holding member that holds the elastic film to the top ring, and the support portion is a protrusion extending from the holding member.

By forming the support portion in a protruding shape, the elongation of the elastic film is not hindered.

It is desirable that the substrate is adsorbed to the lower surface of the elastic film, and the support portion is provided at a portion corresponding to an edge of the substrate being adsorbed.

By providing a support portion in a portion corresponding to the edge, it is possible to particularly suppress deformation of the substrate.

It is desirable that the substrate is adsorbed on the lower surface of the elastic film, and when the substrate is adsorbed, the support portion suppresses a change in shape of the elastic film in a vertical direction.

This can reduce the pressure applied to the substrate.

The top ring may include a retaining ring provided below the main body of the top ring and around the elastic film.

In addition, the retaining ring may include an inner ring and an outer ring provided outside the inner ring.

According to another aspect of the present invention, a substrate polishing apparatus may be provided, including: The top ring; a polishing pad that is in contact with a substrate held on the top ring and polishes the substrate; and a pressure control unit that controls the pressure in an area where the pressure can be adjusted.

It is desirable that, when the substrate is transported before the substrate is polished, the pressure control unit decompresses a first region in the region in which the pressure can be adjusted, and when the substrate is polished, the substrate is polished. When the substrate is lifted off the polishing pad, the pressure control unit decompresses a second region that is wider than the first region in the region where the pressure can be adjusted.

The substrate is adsorbed by decompressing a narrow area during transportation before polishing, so that the pressure applied to the substrate can be reduced. In addition, since a wide area is decompressed and adsorbed when the substrate is lifted off, the substrate can be reliably lifted off.

The substrate can be appropriately processed.

1‧‧‧ top ring

11‧‧‧Top ring body

12‧‧‧ Retaining ring

13‧‧‧ diaphragm

131 ~ 138‧‧‧ area

22, 24, 26, 27‧‧‧Retaining ring

151, 161‧‧‧ support

3a‧‧‧ polishing pad

7‧‧‧Pressure Control Unit

300‧‧‧ substrate polishing device

FIG. 1 is a schematic plan view of a substrate processing apparatus.

FIG. 2 is a schematic perspective view of the substrate polishing apparatus 300.

FIG. 3 is a schematic cross-sectional view of the substrate polishing apparatus 300.

FIG. 4 is a cross-sectional view schematically showing the structure of the top ring 1.

FIG. 5 is a flowchart illustrating a substrate polishing process performed by the substrate polishing apparatus 300.

FIG. 6 is a diagram schematically showing pressure changes in regions 131 to 135. FIG.

FIG. 7 is a diagram illustrating the transfer of the substrate from the transfer mechanism 600 b to the top ring 1 in detail.

FIG. 8 is a diagram illustrating the transfer of the substrate from the transfer mechanism 600 b to the top ring 1 in detail.

FIG. 9 is a graph showing the results of measuring the polishing rate by changing the adsorption range of the substrate.

FIG. 10 is a diagram schematically showing changes in the flow rate in a region and the shape of the diaphragm 13 when the adsorption range of the substrate W is changed and lifted off.

FIG. 11 is a graph in which the amount of deformation of the substrate at the time of lift-off when the adsorption range is widened is measured.

FIG. 12 is a cross-sectional view showing the diaphragm 13.

FIG. 13 is an enlarged sectional view showing a part of the diaphragm 13.

FIG. 14 is a graph in which the amount of deformation of a substrate at the time of lift-off due to the presence or absence of a support portion is measured.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

<First Embodiment>

FIG. 1 is a schematic plan view of a substrate processing apparatus. This substrate processing device is used for semiconductor wafers, flat plates with a diameter of 300mm or 450mm, and image sensors such as CMOS (Complementary Metal Oxide Semiconductor) and CCD (Charge Coupled Device). In addition, various substrates are processed in the manufacturing process of magnetic films such as MRAM (Magnetoresistive Random Access Memory).

The substrate processing apparatus includes a substantially rectangular housing 100, a loading unit 200 for mounting a substrate box storing a large number of substrates, and one or a plurality of (four in the embodiment shown in FIG. 1) substrate polishing apparatus 300; 1 Or more (two in the manner shown in FIG. 1) substrate cleaning apparatus 400; substrate drying apparatus 500; conveying mechanisms 600a to 600d; and control unit 700.

The loading section 200 is disposed adjacent to the casing 100. The loading section 200 can mount an open wafer cassette, a SMIF (Standard Mechanical Interface) wafer cassette, or a FOUP (Front Opening Unified Pod). SMIF wafer cassettes and FOUPs are sealed containers that can store substrate boxes inside and are covered by partition walls to ensure an environment that is independent of the external space.

A substrate polishing apparatus 300 for polishing a substrate, a substrate cleaning apparatus 400 for cleaning a polished substrate, and a substrate drying apparatus 500 for drying a cleaned substrate are housed in a casing 100. The substrate polishing apparatus 300 is arranged along the longitudinal direction of the substrate processing apparatus, and the substrate cleaning apparatus 400 and the substrate drying apparatus 500 are also arranged along the longitudinal direction of the substrate processing apparatus.

A conveyance mechanism 600 a is arranged in a region surrounded by the loading unit 200, the substrate polishing apparatus 300 and the substrate drying apparatus 500 located on the loading unit 200 side. In addition, a conveyance mechanism 600b is arranged in parallel with the substrate polishing apparatus 300, the substrate cleaning apparatus 400, and the substrate drying apparatus 500.

The transfer mechanism 600a receives the substrate before polishing from the loading unit 200 and transfers it to the transfer mechanism 600b, or receives the dried substrate taken out from the substrate drying apparatus 500 from the transfer mechanism 600b.

The transfer mechanism 600 b is, for example, a linear transport device, and transfers the substrate before polishing received from the transfer mechanism 600 a to the substrate polishing device 300. As described later, the substrate polishing apparatus 300 receives a substrate by vacuum suction. The transport mechanism 600b receives the polished substrate again and transfers it to the substrate cleaning apparatus 400.

A transport mechanism 600c is disposed between the two substrate cleaning apparatuses 400. The transfer mechanism 600 c transfers substrates between the substrate cleaning apparatuses 400. A transfer mechanism 600 d is disposed between the substrate cleaning device 400 and the substrate drying device 500. The transfer mechanism 600 d transfers substrates between the substrate cleaning device 400 and the substrate drying device 500.

The control unit 700 is used to control the operations of each device of the substrate processing apparatus. The control unit 700 may be arranged inside the casing 100 or outside the casing 100, or may be separately provided in the substrate polishing apparatus 300, the substrate cleaning apparatus 400, and Substrate drying device 500.

2 and 3 are a schematic perspective view and a schematic cross-sectional view of the substrate polishing apparatus 300, respectively. The substrate polishing apparatus 300 includes: a top ring 1; a top ring shaft 2 connected to the top ring 1 at its lower portion; a polishing table 3 having a polishing pad 3a; a nozzle 4 for supplying a polishing liquid to the polishing table 3; Head 5; support shaft 6; and pressure control unit 7.

The top ring 1 holds the substrate W. As shown in FIG. 3, the top ring 1 is composed of the following components: a top ring main body 11; a ring-shaped retaining ring 12; and a flexible diaphragm 13 (elasticity) provided below the top ring main body 11 and inside the retaining ring 12. Membrane); and an airbag 14 provided between the top ring main body 11 and the retaining ring 12.

By providing the airbag 14, the retaining ring 12 can move relative to the top ring body 11 in the vertical direction. In addition, the space between the top ring body 11 and the diaphragm 13 is decompressed by the pressure control unit 7, and the upper surface of the substrate W is held on the top ring 1 (more specifically, the lower surface of the diaphragm 13). The periphery of the held substrate W is surrounded by the retaining ring 12, and the substrate W does not fly out of the top ring 1 during polishing.

The retaining ring 12 may be a single member or a double-layered ring structure including an inner ring and an outer ring provided on the outer side of the inner ring. In the latter case, the outer ring may be fixed to the top ring main body 11, and the airbag 14 may be provided between the inner ring and the top ring main body 11.

The lower end of the top ring shaft 2 is connected to the center of the upper surface of the top ring 1. Through the not shown The lowering mechanism raises and lowers the top ring shaft 2 so that the lower surface of the substrate W held on the top ring 1 is in contact with or separated from the polishing pad 3a. In addition, when the top ring shaft 2 is rotated by a motor (not shown), the top ring 1 is rotated, and the substrate W held thereby is also rotated.

A polishing pad 3 a is provided on the upper surface of the polishing table 3. The lower surface of the polishing table 3 is connected to a rotating shaft, and the polishing table 3 is rotatable. While the polishing liquid is supplied from the nozzle 4 and the polishing pad 3 a is in contact with the lower surface of the substrate W, the substrate W and the polishing table 3 are rotated to polish the substrate W.

One end of the top ring head 5 is connected to the top ring shaft 2, and the other end is connected to the support shaft 6. The support shaft 6 is rotated by a motor (not shown), so that the top ring head 5 swings, and the top ring 1 communicates with the substrate transfer position (not shown) on the polishing pad 3a.

The pressure control unit 7 supplies fluid between the top ring main body 11 and the diaphragm 13, evacuates the top ring main body 11 and the diaphragm 13, or communicates between the top ring main body 11 and the diaphragm 13 with the atmosphere, The pressure of the space formed between the top ring main body 11 and the diaphragm 13 is adjusted.

FIG. 4 is a cross-sectional view schematically showing the structure of the top ring 1. The diaphragm 13 is formed with peripheral walls 13 a to 13 h extending upward toward the top ring main body 11. Areas 131 to 138 divided by the peripheral walls 13a to 13h are formed between the upper surface of the diaphragm 13 and the lower surface of the top ring main body 11 through these peripheral walls 13a to 13h. The area 131 is located approximately in the center of the top ring 1 and is circular. The area 132 is located outside the area 131 and has a ring shape. Below, the areas 133 to 138 are also circular.

Flow paths 141 to 148 are formed which penetrate the top ring main body 11 and communicate with the regions 131 to 138, respectively. An airbag 14 made of an elastic film is provided directly above the retaining ring 12, and a flow path 149 communicating with the airbag 14 is similarly formed. A pressure sensor or a flow sensor may be provided on the flow path 141 to 149.

The flow paths 141 to 149 are connected to the pressure control unit 7 and can be used for the areas 131 to 138 and the airbag 14 Adjust the pressure. Hereinafter, a configuration example of the pressure control unit 7 will be described.

The pressure control unit 7 includes: a control device 71; on-off valves V1 to V9 and pressure regulators R1 to R9 controlled by the control device 71; and a fluid regulator 72. The flow path 141 is connected to the fluid regulator 72 via the on-off valve V1 and the pressure regulator R1. The flow paths 142 to 149 are the same. The fluid adjustment unit 72 supplies a fluid or performs an evacuation.

For example, when the pressure in the area 131 is adjusted, the control device 71 opens the valve V1 and adjusts the pressure regulator R1. Thereby, the fluid is supplied from the fluid adjustment unit 72 to the region 131 and the region 131 is pressurized, or the fluid adjustment unit 72 evacuates the region 131 and the region 131 is decompressed.

FIG. 5 is a flowchart illustrating a substrate polishing process performed by the substrate polishing apparatus 300. In addition, FIG. 6 is a diagram schematically showing pressure changes in the regions 131 to 135. The solid line is the pressure change in the region 134, and the dotted line is the pressure change in the regions 131 to 133 and 135.

First, by swinging the top ring head 5, the top ring 1 moves to the substrate transfer position, and the pressure control unit 7 decompresses the area 134, so that the substrate W is transferred from the conveying mechanism 600b to the top ring 1. (Step S1).

7 and 8 are diagrams illustrating the transfer of the substrate from the transfer mechanism 600b to the top ring 1 in detail. FIG. 7 is a diagram obtained by observing the conveyance mechanism 600b and the top ring 1 from the side, and FIG. 8 is a diagram obtained by observing the conveyance mechanism 600b and the top ring 1 from above.

As shown in FIG. 7 (a), the substrate W is placed on the hand 601 of the conveyance mechanism 600 b. In addition, a retainer ring station 800 can be used for the transfer of the substrate W. The retaining ring stand 800 has a lift pin 801 that pushes the retaining ring 12 of the top ring 1 upward.

As shown in FIG. 8, the hand 601 supports a part of the outer peripheral side of the lower surface of the substrate W. Minute. The lift pin 801 and the hand 601 are arranged so as not to contact each other.

In the state shown in FIG. 7 (a), the top ring 1 is lowered, and the transport mechanism 600 b is raised. By the lowering of the top ring 1, the lifting pin 801 pushes up the retaining ring 12, and the substrate W approaches the diaphragm 13. When the transport mechanism 600b is further raised, the upper surface of the substrate W is brought into contact with the lower surface of the diaphragm 13 ((b) of FIG. 7).

In this state, the membrane sheet 13 of the top ring 1 attracts the substrate W. Specifically, the pressure control unit 7 in the present embodiment decompresses the area 134 of the areas 131 to 138 (for example, −50 kPa, time t0 to t1 in FIG. 6), whereby the substrate W is adsorbed on the diaphragm 13. At this time, the pressure control unit 7 does not decompress the other regions 131 to 133 and 135 to 138. Therefore, the substrate W is adsorbed and held by a narrower region (that is, a ring-shaped region) below the region 134 in the lower surface of the diaphragm 13, but is not adsorbed at other positions. That is, the adsorption range of the substrate W is narrow.

After the substrate W is attracted to the diaphragm 13 in this way, the conveyance mechanism 600b is lowered (FIG. 7 (c)).

Returning to FIG. 5, in a state where the area 134 is decompressed, the top ring 1 holding the substrate W is swung, and the top ring 1 is moved onto the polishing pad 3 a. Thereby, the substrate W is carried over the polishing pad 3a (step S2 in FIG. 5 and time t1 to t2 in FIG. 6). The adsorption range of the substrate W is narrow, that is, the substrate W is adsorbed by the narrow region of the diaphragm 13, and therefore, the pressure applied to the substrate W can be reduced during transportation before polishing.

Then, as the top ring shaft 2 descends, the lower surface of the substrate W comes into contact with the upper surface of the polishing pad 3a. In this state, the pressure control unit 7 presses the regions 131 to 138 to press the lower surface of the substrate W against the polishing pad 3a (step S3 in FIG. 5 and times t2 to t3 in FIG. 6). At this time, only the area 134 is decompressed in advance. Therefore, the shape of the diaphragm 13 is changed from the shape for transportation before grinding to a ground. The time required for the grinding shape is short, and the pressure control unit 7 can quickly press the areas 131 to 138 to a desired pressure.

Thereafter, the substrate W is polished by rotating the top ring 1 and the polishing table 3 while supplying the polishing liquid from the nozzle 4 to the polishing pad 3a (step S4 in FIG. 5 and times t3 to t4 in FIG. 6).

When the polishing is completed, the substrate W is adsorbed on the lower surface of the diaphragm 13 of the top ring 1. Specifically, the pressure control unit 7 in this embodiment decompresses not only the area 134 among the areas 131 to 138 but also the areas 131 to 133 and 135 (for example, -50 kPa, step S5 in FIG. 5, FIG. 5 From time t4 to t5 at 6), the substrate W is attracted to the diaphragm 13. Therefore, the substrate W is adsorbed by a wide area below the areas 131 to 135 in the diaphragm 13. That is, the adsorption range of the substrate W is wide.

In this way, the top ring 1 uses a ring-shaped (relatively narrow) region 134 to adsorb the substrate W on the conveying mechanism 600b during transportation, and, after grinding, uses concentric circles and wider regions 131 to 135 after grinding. The substrate W on the polishing pad 3a is attracted. In more detail, after grinding, the top ring 1 is adsorbed by the inner regions 131 to 133 and the outer regions 135 of the region 134 in addition to the adsorption by the annular region 134 during transportation.

When the top ring shaft 2 is raised while the areas 131 to 135 are decompressed, the substrate W is lifted off the polishing pad 3a (step S6 in FIG. 5).

A liquid such as a polishing liquid is present between the substrate W and the polishing pad 3a, and an adsorption force is generated between the substrate W and the polishing pad 3a. If the top ring 1 is weak in attracting the substrate W, the substrate W may not be lifted off and the substrate W may not be picked up. In contrast, in the present embodiment, the substrate W has a wide adsorption range, that is, the substrate W is adsorbed by a wide area of the diaphragm 13. Therefore, the adsorption force between the substrate W and the diaphragm 13 is higher than that of the substrate W and polishing. The adsorption force between the pads 3n is large. Therefore, the top ring 1 can be reliably The substrate W is lifted off.

After that, in a state where the regions 131 to 135 are decompressed, the substrate W is transferred from the top ring 1 to the transfer mechanism 600b at the substrate transfer position (step S7).

As described above, in the present embodiment, the adsorption range of the substrate W is narrowed during transportation before polishing. This can reduce the pressure on the substrate W, and can stabilize the polishing rate during polishing.

FIG. 9 is a graph showing the results of measuring the polishing rate by changing the adsorption range of the substrate. As described in this embodiment, the square mark is a result of the case where the adsorption range is narrowed (only in the area 134) during the transportation before grinding (step S2 in FIG. 5). The round mark is used as a comparative example. This is the result of the widened range (regions 131 to 135) during the transportation before grinding. Each of the ten substrates was polished to measure the polishing rate, and each substrate was used as the horizontal axis. In addition, the vertical axis is a measurement result (the unit is arbitrary) of the polishing rate of the substrate below the region 133. In the comparative example of FIG. 9, if the adsorption range is widened, the polishing rate of some substrates is greatly increased compared to other substrates, and the polishing rate is unstable. On the other hand, in this embodiment, by narrowing the adsorption range, the polishing rate of the substrate is stabilized.

In addition, in this embodiment, the adsorption range of the substrate W is widened during lift-off. Thereby, the holding force of the top ring 1 becomes high, the substrate W can be reliably lifted off, and the shape change of the diaphragm 13 can be suppressed.

FIG. 10 is a diagram schematically showing changes in the flow rate in a region and the shape of the membrane sheet 13 when the suction range of the substrate W is changed and separated. The upper layer of FIG. 10 is a comparative example of the case where the adsorption range at the time of lift-off is narrowed (only in the region 134), and the lower layer of FIG. 10 is made wider at the time of lift-off (the regions 131 to 135) Case of this embodiment.

In the comparative example, the region 134 is adsorbed, but the other regions 131 to 133 and 135 to 138 are not adsorbed and are in a free state. At time t1, at the time point when the top ring 1 starts to rise, the substrate W is pulled by the polishing pad 3a, the diaphragm 13 is extended, and the volume of the regions 131 to 138 becomes large. As a result, the gas flows into the regions 131 to 138, and the flow rate is positive.

After that, at time t2 when the top ring 1 further rises, the substrate W is separated from the polishing pad 3a by the tension of the diaphragm 13, the diaphragm 13 returns to its original state, and the volume of the regions 131 to 138 becomes small. Therefore, the flow rate is temporarily negative, and thereafter, the flow rate is stabilized and becomes 0.

In this way, when the adsorption range at the time of lift-off is narrow, there is a change in the shape of the membrane 13 and the flow rate in the regions 131 to 138 is unstable.

On the other hand, in this embodiment, the regions 131 to 135 are adsorbed. At time t1, at the time point when the top ring 1 starts to rise, the adsorption range is wide, so the influence of the substrate W being dragged by the polishing pad 3a is small, and the substrate W is immediately separated from the polishing pad 3a. Therefore, there is almost no change in the shape of the diaphragm, and the flow rate in the regions 131 to 138 is stable and is 0.

In this way, in the first embodiment, the adsorption range of the substrate W is narrowed during transportation before polishing, and the adsorption range of the substrate W is widened during transportation after polishing. As a result, the pressure applied to the substrate W can be reduced, the polishing rate can be stabilized, and the lift-off can be reliably performed. Therefore, the substrate can be properly processed from the time when the substrate W is received to the time when it is lifted off, and it is possible to suppress defects such as cracking of the substrate, transportation errors such as falling of the substrate, and failure to pick up the substrate, thereby improving yield and productivity.

In addition, in the present embodiment, only the area 134 is decompressed during the transportation before polishing, and the areas 131 to 135 are decompressed during the transportation after polishing. However, the present invention is not limited to this. It is sufficient to have a wide adsorption range during transportation before grinding. For example: When transporting before grinding, it is possible to reduce the pressure of the circular area instead of the circular area to adsorb it. Substrate W. Specifically, when transporting before grinding, either the area 131 may be decompressed, the areas 131, 132 may be decompressed, or the areas 131 to 133 may be decompressed. In addition, when transporting after grinding, compare regions with a wide adsorption range during transporting before grinding--for example, a region that has been decompressed during transport before grinding and an area that is inside and / or outside of the decompressed region, Decompression is sufficient.

<Second Embodiment>

The first embodiment described above is an embodiment in which the adsorption range is widened during lift-off. However, depending on the situation, the substrate may be deformed due to a wide adsorption range, and pressure may be applied to the substrate.

FIG. 11 is a graph in which the amount of deformation of the substrate at the time of lift-off when the adsorption range is widened is measured. This FIG. 11 is a diagram of a 300 mm substrate. The horizontal axis is the position on the substrate, and the vertical axis is the amount of deformation (however, the polishing pad 3a side is positive downward). As shown in the figure, the substrate is largely deformed on the outer periphery. In addition, deformation is generated from the position of about 100 mm from the center of the substrate, and pressure is applied to the position.

Therefore, in the second embodiment described below, a support portion is provided between the top ring body 11 and the diaphragm 13, and deformation of the substrate is suppressed by suppressing deformation of the diaphragm 13.

FIG. 12 is a cross-sectional view showing the diaphragm 13. The diaphragm 13 includes a circular abutting portion 130 that is in contact with the substrate W, and eight peripheral walls 13 a to 13 h that are directly or indirectly connected to the abutting portion 130. The abutting portion 130 is in contact with the back surface of the substrate W, that is, the surface on the opposite side to the surface to be polished, and is held. The contact portion 130 presses the substrate W against the polishing pad 3 a during polishing. The peripheral walls 13a to 13h are annular peripheral walls arranged concentrically.

The upper ends of the peripheral walls 13a to 13h are clamped by the retaining rings 22, 24, 26, 27 and the top ring The top ring body 11 is mounted between the lower surfaces of the main body 11. These retaining rings 22, 24, 26, and 27 are detachably fixed to the top ring main body 11 by a retaining unit (not shown). Therefore, when the holding unit is released, the holding rings 22, 24, 26, and 27 are separated from the top ring main body 11, so that the diaphragm 13 can be detached from the top ring main body 11. As the holding unit, a screw or the like can be used.

The peripheral wall 13h is the outermost peripheral wall, and the peripheral wall 13g is arranged radially inward of the peripheral wall 13h. The peripheral wall 13f is disposed on the radially inner side of the peripheral wall 13g. Hereinafter, the peripheral wall 13h is referred to as a first peripheral wall, the peripheral wall 13g is referred to as a second peripheral wall, and the peripheral wall 13f is referred to as a third peripheral wall.

FIG. 13 is an enlarged sectional view showing a part of the diaphragm 13. In order to adjust the polishing speed in a narrow range of the edge portion of the substrate W, the diaphragm 13 has a shape as shown in FIG. 13. Hereinafter, the diaphragm 13 will be described in detail. The first edge peripheral wall 13h extends upward from the peripheral end portion of the abutting portion 130, and the second edge peripheral wall 13g is connected to the first edge peripheral wall 13h.

The second edge peripheral wall 13g has an outer horizontal portion 1110 connected to the inner peripheral surface 1010 of the first edge peripheral wall 13h. The inner peripheral surface 1010 of the first edge peripheral wall 13h includes an upper inner peripheral surface 1010a and a lower inner peripheral surface 1010b extending perpendicularly to the abutting portion 130. The upper inner peripheral surface 1010a extends upward from the horizontal portion 1110 of the second peripheral wall 13g, and the lower inner peripheral surface 1010b extends downward from the horizontal portion 1110 of the second peripheral wall 13g. In other words, the outer horizontal portion 1110 of the second peripheral wall 13g is connected to a position that divides the inner peripheral surface 1010 extending perpendicularly to the abutting portion 130. The lower inner peripheral surface 1010 b is connected to a terminal portion of the abutting portion 130. An outer peripheral surface 1020 located outside the lower inner peripheral surface 1010b also extends perpendicularly to the abutting portion 130. The upper inner peripheral surface 1010a and the lower inner peripheral surface 1010b are located in the same plane. The “same surface” is an imaginary surface perpendicular to the abutting portion 130. That is, the radial position of the upper inner peripheral surface 1010a and the radial position of the lower inner peripheral surface 1010b are the same.

The first edge peripheral wall 13h has a bent portion that allows the contact portion 130 to move up and down. 1030. The bent portion 1030 is connected to the upper inner peripheral surface 1010a. The bent portion 1030 has a bellows structure that is configured to expand and contract in a direction perpendicular to the abutting portion 130 (that is, a vertical direction). Therefore, even if the distance between the top ring main body 11 and the polishing pad 3 a is changed, the contact between the peripheral end portion of the contact portion 130 and the substrate W can be maintained. The first edge peripheral wall 13h has an edge portion 1040 extending radially inward from the upper end of the bent portion 1030. The edge portion 1040 is fixed to the lower surface of the top ring main body 11 through the retaining ring 27 shown in FIG. 12.

The second edge peripheral wall 13g has an outer horizontal portion 1110 extending horizontally from the inner peripheral surface 1010 of the first edge peripheral wall 13h. Further, the second edge peripheral wall 13g has: an inclined portion 1120 connected to the outer horizontal portion 1110; an inner horizontal portion 1130 connected to the inclined portion 1120; a vertical portion 1140 connected to the inner horizontal portion 1130; and an edge portion 1150 , Which is connected to the vertical portion 1140. The inclined portion 1120 extends radially inward from the outer horizontal portion 1110 and is inclined upward. The edge portion 1150 extends radially outward from the vertical portion 1140 and is fixed to the lower surface of the top ring main body 11 through the retaining ring 27 shown in FIG. 12. If the first peripheral wall 13h and the second peripheral wall 13g are mounted on the lower surface of the top ring main body 11 through the retaining ring 27, a region 138 is formed between the first peripheral wall 13h and the second peripheral wall 13g.

The third edge peripheral wall 13f is disposed radially inward of the second edge peripheral wall 13g. The third peripheral wall 13f has an inclined portion 1210 connected to the upper surface of the abutting portion 130, a horizontal portion 1220 connected to the inclined portion 1210, a vertical portion 1230 connected to the horizontal portion 1220, and an edge portion 1240, It is connected to the vertical portion 1230. The inclined portion 1210 extends inward in the radial direction from the upper surface of the contact portion 130 and is inclined upward. The edge portion 1240 extends radially inward from the vertical portion 1230 and is fixed to the lower surface of the top ring main body 11 through the retaining ring 26 shown in FIG. 12. If the second edge peripheral wall 13g and the third edge peripheral wall 13f are respectively mounted on the lower surface of the top ring main body 11 through the retaining rings 27 and 26, then A region 137 is formed between the peripheral wall 13g and the third peripheral wall 13f.

The peripheral wall 13e is arranged radially inward of the third edge peripheral wall 13f. The peripheral wall 13e has an inclined portion 1310 connected to the upper surface of the abutting portion 130, a horizontal portion 1320 connected to the inclined portion 1310, a vertical portion 1330 connected to the horizontal portion 1320, and an edge portion 1340 connected to The vertical part 1330. The inclined portion 1310 extends radially inward from the upper surface of the contact portion 130 and is inclined upward. The edge portion 1340 extends radially outward from the vertical portion 1330 and is fixed to the lower surface of the top ring main body 11 through the retaining ring 26 shown in FIG. 12. When the peripheral wall 13e and the third edge peripheral wall 13f are mounted on the lower surface of the top ring main body 11 through the retaining ring 26, a region 136 is formed between the peripheral wall 13e and the third edge peripheral wall 13f.

The peripheral walls 13b and 13d shown in FIG. 12 have substantially the same structure as the third edge peripheral wall 13f shown in FIG. 12, and the peripheral walls 13a and 13c shown in FIG. 12 have substantially the same structure as those of the peripheral wall 13e shown in FIG. Therefore, their description is omitted. As shown in FIG. 12, the edges of the peripheral walls 13 a and 13 b are fixed to the lower surface of the top ring main body 11 through the retaining ring 22, and the edges of the peripheral walls 13 c and 13 d are fixed to the lower surface of the top ring main body 11 through the retaining ring 24. In addition, in the regions 131, 133, and 135, rings 21, 23, and 25 protruding from the top ring main body 11 are formed, respectively.

The area 136 formed below the retaining ring 26 is narrower than the areas 132 and 134 formed below the retaining rings 22 and 24 and the areas 131, 133 and 135 below the rings 21, 23, and 25, respectively.

The top ring 1 in this embodiment has a support portion 161 located in the region 136 and extending toward the diaphragm 13. Specifically, the support portion 161 extends downward between the peripheral wall 13e and the peripheral wall 13f of the diaphragm 13, and more specifically, is inclined substantially parallel to the inclined portion 1310 (FIG. 13) of the peripheral wall 13e, but does not extend to the peripheral wall 13f. Below the horizontal portion 1220. The lower surface of the support portion 161 is substantially parallel to the diaphragm 13. The support portion 161 is a member integrated with the retaining ring 26, and may be The holding ring 26 extends a concentric annular protrusion.

In addition, the top ring 1 may have a support portion 151 located in the region 134 and extending substantially parallel to the diaphragm 13. The support portion 151 may be a member integral with the retaining ring 24 and may be a concentric annular protrusion extending from the retaining ring 24.

Thus, it is desirable that the lower surface of the retaining ring 22, the lower surface of the retaining ring 24, the lower surface of the support portion 151, and the lower surface of the support portion 161 (also integrated with the top ring body 11 of the regions 131, 133, and 135 The lower surfaces of the rings 21, 23, 25) are on the same plane as much as possible.

The support portions 161 and 151 are protrusion-shaped and do not hinder the vertical and radial elongation of the diaphragm 13. However, when the area is depressurized and the substrate is held, changes in the shape of the diaphragm 13 in the vertical direction are suppressed. Therefore, even when the substrate is adsorbed in a wide area (for example, the above-mentioned areas 131 to 135) during the post-polishing transportation, the deformation of the substrate can be suppressed as much as possible, and the substrate can be held flat and uniformly, which can suppress the substrate. pressure.

When the film 13 is used to adsorb the substrate, the region 136 corresponds to a portion that comes into contact with the edge of the substrate (within about 20 mm from the periphery of the substrate). In addition, the region 136 is narrower than the inner regions 131 to 135. Generally, in order to improve the edge controllability of the polishing contour, it is difficult to think of providing a support portion in such an area 136. However, in the present embodiment, the support portion is intentionally provided in a region 136 corresponding to the edge of the substrate, so as to suppress the deformation of the substrate.

FIG. 14 is a graph in which the amount of deformation of a substrate at the time of lift-off due to the presence or absence of a support portion is measured. The solid line in FIG. 14 shows a case where a support portion is present. The dotted line in FIG. 14 is a case where there is no support portion, and is the same as that in FIG. 11. As shown in the figure, if the support portion is not provided, the outer peripheral portion of the substrate is greatly deformed. However, by providing the support portion, the shape change of the substrate W can be suppressed to less than half.

In this way, in the second embodiment, a support portion is provided in an area. Therefore, when the substrate is adsorbed in a wide range, the shape change of the diaphragm 13 can be suppressed, and the pressure on the substrate can be reduced.

The above-mentioned embodiment is described for the purpose that a person having ordinary knowledge in the technical field to which the present invention pertains can implement the present invention. As long as a person skilled in the art can certainly implement various modifications of the above-mentioned embodiment, the technical idea of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, and should be the widest range according to the technical idea defined by the scope of patent application.

S1 ~ S7‧‧‧step

Claims (15)

A substrate polishing method includes: a transporting step in which a substrate is adsorbed by a first region of an elastic film and the substrate is transported to a polishing pad; and a polishing step in which the substrate and The polishing pad contacts and polishes the substrate; and a lift-off step in which the substrate is adsorbed by using a second region of the elastic film that is wider than the first region, and The substrate is lifted off from the polishing pad. A substrate polishing method comprising a conveying step in which a first region of an area in which the pressure formed between a top ring main body and an elastic film can be adjusted is decompressed, and the above-mentioned method is utilized. The lower surface of the elastic film adsorbs the substrate and transfers the substrate to a polishing pad; a polishing step in which the substrate is brought into contact with the polishing pad and the substrate is polished; and a lift-off step in which In the lift-off step, the second region which is wider than the first region in the region where the pressure can be adjusted is decompressed, so that the substrate is removed from the substrate by using the lower surface of the elastic film to adsorb the substrate. The polishing pad is lifted off. The substrate polishing method according to item 2 of the scope of patent application, wherein a plurality of regions capable of adjusting pressure are formed between the top ring body and the elastic film; the first region includes the plurality of regions The second region includes a region in which the number of regions is greater than the predetermined number. The substrate polishing method according to item 3 of the scope of patent application, wherein the second region is concentric with the first region, and the second region is wider than the first region. The substrate polishing method according to item 3 of the scope of patent application, wherein the first region is a circular or circular region. The substrate polishing method according to any one of claims 2 to 5, wherein in the polishing step, at least a part of an area where the pressure can be adjusted is pressurized. The substrate polishing method according to any one of claims 2 to 5, wherein a support portion extending toward the elastic film is provided in an area where the pressure can be adjusted. A top ring for holding a substrate, the top ring comprising: a top ring body; and an elastic film, which is disposed below the top ring body, and is formed between the elastic film and the top ring body An area where the pressure can be adjusted; and a support portion provided in the area and extending toward the elastic membrane. The top ring according to claim 8 includes a holding member that holds the elastic film on the top ring, and the support portion is a protrusion extending from the holding member. The top ring according to item 8 or 9 of the scope of the patent application, wherein the substrate is adsorbed on the lower surface of the elastic film, and the support portion is provided at a portion corresponding to the edge of the substrate being adsorbed. The top ring according to item 8 or 9 of the scope of patent application, wherein the substrate is adsorbed on the lower surface of the elastic film, and when the substrate is adsorbed, the support portion suppresses the vertical direction of the elastic film. Shape change. The top ring according to item 8 or 9 of the scope of application for a patent, further comprising a retaining ring, which is disposed below the main body of the top ring and located around the elastic film. The top ring according to claim 12, wherein the retaining ring includes an inner ring and an outer ring provided on the outer side of the inner ring. A substrate polishing device comprising: a top ring according to item 8 or 9 of the scope of patent application; a polishing pad which is in contact with a substrate held on the top ring and polishes the substrate; and a pressure control unit The pressure control unit controls the pressure in the area where the pressure can be adjusted. The substrate polishing device according to item 14 of the scope of application for a patent, wherein the pressure control unit decompresses the first region in the region where the pressure can be adjusted when the substrate is transported before the substrate is polished; When the substrate is lifted off the polishing pad after the substrate is polished, the pressure control unit performs a second region wider than the first region in the region where the pressure can be adjusted. stress reliever.