TWI730044B - Substrate grinding method, top ring and substrate grinding device - Google Patents

Abstract

The present invention provides a substrate polishing method, a substrate polishing device, and a top ring used in such a substrate polishing device that can appropriately process substrates. The present invention provides a substrate polishing method, including the following steps: a transport step (S2), in the transport step (S2), a first region of an elastic film is used to adsorb a substrate and transport the substrate onto a polishing pad; a polishing step (S4) In the polishing step (S4), the substrate is brought into contact with the polishing pad and the substrate is polished; and the lift-off step (S6), in which the elasticity is used The second region of the film, which is wider than the first region, adsorbs the substrate and lifts the substrate from the polishing pad.

Description

Substrate grinding method, top ring and substrate grinding device

The present invention relates to a substrate polishing method for polishing a substrate, a top ring that holds the substrate, and a substrate polishing apparatus provided with such a top ring.

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

Prior art literature

Patent literature

Patent Document 1: Japanese Patent No. 5390807

Patent Document 2: Japanese Patent Application Publication No. 2009-178800

In Patent Document 1, vacuum suction is performed to the same degree regardless of when the substrate is transported to the polishing pad or when the substrate is lifted off. However, if the vacuum suction force is too strong, When the substrate is transported to the polishing pad, pressure is applied to the substrate, which may damage the substrate. On the contrary, if the vacuum suction force is too weak, the substrate may crack and fail to be picked up when the substrate is lifted off. The reason is that the polishing liquid exists 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 degree of vacuum is increased during lift-off compared to when the substrate is transported to the polishing pad. However, it does not increase the degree of vacuum of the entire diaphragm, and therefore, it may not be able to be lifted off reliably.

The present invention has been completed in view of such problems. The problem of the present invention is to provide a substrate polishing method, a substrate polishing apparatus, and a top ring used in such a substrate polishing apparatus that can appropriately process substrates.

According to an aspect of the present invention, there can be provided a substrate polishing method including the following steps: a transport step, in which the first region of the elastic film is used to adsorb the substrate and transport the substrate to the 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 elastic film is higher than the first The wide second area adsorbs the substrate and lifts the substrate from the polishing pad.

When the substrate is transported to the polishing pad, a narrow area is used to suck the substrate, so the pressure applied to the substrate can be reduced. In addition, when the substrate is lifted off, a wider area is used to adsorb the substrate, so the substrate can be lifted off reliably.

According to another aspect of the present invention, it is possible to provide a substrate polishing method including the following steps: a transport step in which the pressure formed between the top ring main body and the elastic membrane can be adjusted in the area ( area) is reduced in pressure, so that the lower surface of the elastic film is used to adsorb the substrate and transport the substrate to the polishing pad; the polishing step, 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 the pressure is reduced in a second region wider than the first region in the region where the pressure can be adjusted, so as to utilize the elasticity The lower surface of the film adsorbs the substrate to lift the substrate from the polishing pad.

When the substrate is transported to the polishing pad, a narrow area is reduced in pressure to adsorb the substrate, so the pressure applied to the substrate can be reduced. In addition, when the substrate is lifted off, a wide area is decompressed to adsorb the substrate, so the substrate can be lifted off reliably.

It is also possible that a plurality of regions whose pressure can be adjusted are 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 regions in the plurality of regions whose number is greater than the predetermined number.

As a result, the second area can be made wider than the first area.

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

In this case, the area where the pressure is reduced before polishing is narrow, and therefore, it is possible to quickly pressurize to a desired pressure during polishing.

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

By providing the support part, even if a wider area is used for adsorption during lift-off, the shape of the elastic membrane changes less and the pressure applied to the substrate can be reduced.

According to an aspect of the present invention, there can be provided a top ring for holding a substrate, the top ring having: a top ring main body; an elastic membrane provided below the top ring main body, between the elastic membrane and the A region where the pressure can be adjusted is formed between the main body of the top ring; and a support part, which is arranged in the region and extends toward the elastic membrane.

By providing the support part, even if a wider area is used for adsorption during lift-off, the shape of the elastic membrane changes less and the pressure applied to the substrate can be reduced.

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

By forming the support portion in the shape of a protrusion, the extension 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 the edge of the substrate to be adsorbed.

By providing the support portion at the portion corresponding to the edge, the deformation of the substrate can be particularly suppressed.

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

As a result, the pressure applied to the substrate can be reduced.

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

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 device can 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 the area where the pressure can be adjusted.

It is desirable that the pressure control unit depressurizes the first area in the area where the pressure can be adjusted during the transport before the substrate is polished, and when the substrate is polished, the pressure is reduced. When the substrate is lifted from the polishing pad, the pressure control unit decompresses a second region that is wider than the first region among the regions where the pressure can be adjusted.

When transporting before polishing, the narrow area is reduced in pressure to adsorb the substrate, so the pressure applied to the substrate can be reduced. In addition, when the substrate is lifted off, a wide area is decompressed for adsorption, so the substrate can be lifted off reliably.

The substrate can be properly processed.

1‧‧‧Top ring

11‧‧‧Top ring main body

12‧‧‧Retaining ring

13‧‧‧Diaphragm

131~138‧‧‧Region

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 device 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 the substrate polishing process performed by the substrate polishing apparatus 300.

Fig. 6 is a diagram schematically showing pressure changes in areas 131 to 135.

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

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

FIG. 9 is a graph showing the result 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 of the area and the shape of the diaphragm 13 in the case where the suction range of the substrate W is changed and lift-off is performed.

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

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

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

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

Hereinafter, the embodiments of the present invention will be described in detail 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 and flat panels with a diameter of 300mm or 450mm, as well as image sensors such as CMOS (Complementary Metal Oxide Semiconductor) and CCD (Charge Coupled Device), And MRAM (Magnetoresistive Random Access Memory: Magnetoresistive Random Access Memory) processes various substrates in the manufacturing process of the magnetic film.

The substrate processing apparatus includes: a substantially rectangular housing 100; a loading unit 200 for mounting a substrate cassette for storing a large number of substrates; one or more (four in the form shown in FIG. 1) substrate polishing apparatus 300; 1 One or more (two in the method shown in Figure 1) substrate cleaning device 400; substrate drying device 500; conveying mechanisms 600a to 600d; and control unit 700.

The loading part 200 is arranged adjacent to the housing 100. An open wafer cassette, a SMIF (Standard Mechanical Interface) wafer cassette, or a FOUP (Front Opening Unified Pod) can be mounted on the loading unit 200. SMIF wafer cassettes and FOUPs are airtight containers that can store substrate cassettes inside and are covered by partition walls to ensure an environment independent of the external space.

The substrate polishing device 300 that polishes the substrate, the substrate cleaning device 400 that cleans the polished substrate, and the substrate drying device 500 that dries the cleaned substrate are housed in the housing 100. The substrate polishing device 300 is arranged along the longitudinal direction of the substrate processing device, and the substrate cleaning device 400 and the substrate drying device 500 are also arranged along the longitudinal direction of the substrate processing device.

A transport mechanism 600 a is arranged in an area surrounded by the loading unit 200, the substrate polishing device 300 on the loading unit 200 side, and the substrate drying device 500. In addition, a transport mechanism 600b is arranged in parallel with the substrate polishing device 300, the substrate cleaning device 400, and the substrate drying device 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 device 500 from the transfer mechanism 600b.

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

Furthermore, a transport mechanism 600c is arranged between the two substrate cleaning devices 400, The transfer mechanism 600c transfers substrates between these substrate cleaning devices 400. In addition, a transport mechanism 600 d is arranged between the substrate cleaning apparatus 400 and the substrate drying apparatus 500, and the transport mechanism 600 d transfers the substrates between the substrate cleaning apparatus 400 and the substrate drying apparatus 500.

The control unit 700 is used to control the actions of the various equipment of the substrate processing apparatus, and may be arranged inside the housing 100 or outside the housing 100, or may be arranged in the substrate polishing apparatus 300, the substrate cleaning apparatus 400, and the substrate polishing apparatus 300, respectively. The substrate drying apparatus 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 device 300 has: a top ring 1; a top ring shaft 2 to which the top ring 1 is connected; a polishing table 3 having a polishing pad 3a; a nozzle 4 that supplies 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 Figure 3, the top ring 1 is composed of the following components: a top ring body 11; an annular retaining ring 12; a flexible diaphragm 13 (elastic Membrane); and an airbag 14 arranged between the top ring body 11 and the retaining ring 12.

By providing the airbag 14, the retaining ring 12 can relatively move in the vertical direction with respect to the top ring main body 11. In addition, the pressure control unit 7 reduces the pressure in the space between the top ring main body 11 and the diaphragm 13, and the upper surface of the substrate W is held by 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.

In addition, the retaining ring 12 may be a single member, or may have a double-layer ring structure composed of an inner ring and an outer ring provided on the outside 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 comes into contact with or separates from the polishing pad 3a. In addition, by rotating the top ring shaft 2 by a motor not shown, the top ring 1 rotates, and the substrate W held thereby also rotates.

A polishing pad 3a is provided on the upper surface of the polishing table 3. The lower surface of the grinding table 3 is connected with a rotating shaft, and the grinding table 3 is rotatable. In a state where the polishing liquid is supplied from the nozzle 4 and the polishing pad 3a is in contact with the lower surface of the substrate W, the substrate W and the polishing table 3 are rotated, so that the substrate W can be polished.

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 moves between the polishing pad 3a and the substrate transfer position (not shown).

The pressure control unit 7 supplies fluid between the top ring main body 11 and the diaphragm 13, or evacuates the space between the top ring main body 11 and the diaphragm 13, or connects 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. Through these peripheral walls 13 a to 13 h, regions 131 to 138 partitioned by the peripheral walls 13 a to 13 h are formed between the upper surface of the diaphragm 13 and the lower surface of the top ring main body 11. 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 is annular. Hereinafter, the areas 133 to 138 are also annular.

Flow paths 141 to 148 that penetrate the top ring main body 11 and communicate with the areas 131 to 138, respectively, are formed. In addition, 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. It is also possible to install pressure sensors and flow sensors on the flow paths 141 to 149.

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

The pressure control unit 7 has: 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 adjustment unit 72. The flow path 141 is connected to the fluid adjusting unit 72 via the on-off valve V1 and the pressure regulator R1. The same goes for flow paths 142 to 149. The fluid adjusting part 72 supplies fluid or performs vacuuming.

For example, when adjusting the pressure of the area 131, the control device 71 opens the valve V1 to adjust the pressure regulator R1. As a result, the fluid is supplied from the fluid adjustment unit 72 to the area 131 and the area 131 is pressurized, or the fluid adjustment unit 72 evacuates the area 131 and the area 131 is decompressed.

FIG. 5 is a flowchart illustrating the substrate polishing process performed by the substrate polishing apparatus 300. In addition, FIG. 6 is a diagram schematically showing the pressure change in the areas 131 to 135, the solid line is the pressure change in the area 134, and the broken line is the pressure change in the areas 131 to 133, 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 transport mechanism 600b to the top ring 1. (Step S1).

7 and 8 are diagrams illustrating in detail the transfer of the substrate from the transport mechanism 600b to the top ring 1. Fig. 7 is a view of the conveying mechanism 600b and the top ring 1 viewed from the side, and Fig. 8 is a view of the conveying mechanism 600b and the top ring 1 viewed from above.

As shown in FIG. 7(a), the substrate W is placed on the hand 601 of the transport mechanism 600b. In addition, a retainer ring station 800 can be used for the transfer of the substrate W. The retaining ring stand 800 has a lifting 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. Also, 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), while the top ring 1 is lowered, the transport mechanism 600b is raised. When the top ring 1 is lowered, the lifting pin 801 pushes the retaining ring 12 upward, and the substrate W approaches the diaphragm 13. When the transport mechanism 600b further rises, the upper surface of the substrate W will contact the lower surface of the diaphragm 13 (FIG. 7(b)).

In this state, the diaphragm 13 of the top ring 1 adsorbs the substrate W. Specifically, the pressure control unit 7 in the present embodiment decompresses the area 134 among 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 areas 131 to 133 and 135 to 138. Therefore, the substrate W is adsorbed and held by a narrow area (that is, an annular area) below the area 134 on the lower surface of the diaphragm 13, but is not adsorbed to other positions. That is, the adsorption range of the substrate W is narrow.

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

Returning to FIG. 5, in a state where the area 134 is decompressed, the top ring 1 is moved onto the polishing pad 3a by swinging the top ring head 5 holding the substrate W. Thereby, the substrate W is conveyed above the polishing pad 3a (step S2 in FIG. 5, time t1 to t2 in FIG. 6). The adsorption range of the substrate W is narrow, that is, the substrate W is adsorbed by a narrow area 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 areas 131 to 138 to press the lower surface of the substrate W against the polishing pad 3a (step S3 in FIG. 5, time t2 to t3 in FIG. 6). At this time, only the area 134 is pre-decompressed. Therefore, the shape of the diaphragm 13 is changed from the shape used for transportation before grinding to the grinding The time required for the grinding shape is relatively short, and the pressure control unit 7 can quickly pressurize the areas 131 to 138 to the desired pressure.

After that, 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, the substrate W is polished (step S4 in FIG. 5, time t3 to t4 in FIG. 6).

After 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 the present embodiment not only reduces the pressure in the area 134 among the areas 131 to 138, but also reduces the pressure in the areas 131 to 133, 135 (for example, -50 kPa, step S5 in FIG. 5, and FIG. From time t4 to t5 at 6), the substrate W is adsorbed on the diaphragm 13 by this. Therefore, the substrate W is adsorbed by the wider area below the areas 131 to 135 in the diaphragm 13. In other words, the adsorption range of the substrate W is relatively wide.

In this way, the top ring 1 uses the annular (relatively narrow) area 134 to adsorb the substrate W on the transport mechanism 600b during transportation, and uses the concentric and wider areas 131 to 135 after polishing. The substrate W on the polishing pad 3a is adsorbed. In more detail, after the top ring 1 is polished, in addition to being adsorbed by the annular area 134 during transportation, it is also adsorbed by the areas 131 to 133 inside the area 134 and the area 135 outside the area 134.

The top ring shaft 2 is raised in a state where the regions 131 to 135 are decompressed, and the substrate W is lifted from the polishing pad 3a (step S6 in FIG. 5).

A liquid such as a polishing liquid exists 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 force of the top ring 1 to adsorb the substrate W is weak, the substrate W cannot be lifted off sometimes and the substrate W cannot be picked up. In contrast, in the present embodiment, the adsorption range of the substrate W is wider, that is, the substrate W is adsorbed by a wider area of the diaphragm 13, and therefore, the adsorption force between the substrate W and the diaphragm 13 is higher than that between the substrate W and the polishing pad. The adsorption force between the pads 3n is large. Therefore, the top ring 1 can be reliably The substrate W is lifted off ground.

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

As described above, in the present embodiment, the suction range of the substrate W is narrowed during transportation before polishing. Thereby, the pressure on the substrate W can be reduced, and the polishing rate during polishing can be stabilized.

FIG. 9 is a graph showing the result of measuring the polishing rate by changing the adsorption range of the substrate. The square mark is the result of the case where the suction range during transportation before polishing (step S2 in FIG. 5) is narrowed (only area 134) as described in this embodiment, and the round mark is used as a comparative example. This is the result of a situation where the adsorption range during transportation before polishing is widened (regions 131 to 135). Each of 10 substrates was polished, and the polishing rate was measured, with each substrate as the horizontal axis. In addition, the vertical axis is the measurement result of the polishing rate of the substrate below the area 133 (the unit is arbitrary). In the comparative example of FIG. 9, if the adsorption range is widened, the polishing speed of some substrates is significantly higher than that of the other substrates, and the polishing speed becomes unstable. In contrast, in the present 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 at the time of lift-off. As a result, the holding force of the top ring 1 is increased, the substrate W can be reliably lifted off, and the change in the shape of the diaphragm 13 can be suppressed.

FIG. 10 is a diagram schematically showing changes in the flow rate of the area and the shape of the diaphragm 13 in the case where the adsorption range of the substrate W is changed and lifted off. The upper layer of FIG. 10 is a comparative example of a case where the adsorption range during lift-off is narrowed (only area 134), and the lower layer of FIG. 10 is a case where the adsorption range during lift-off is widened (area 131~135) Case of this embodiment.

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

Thereafter, at time t2 when the top ring 1 further rises, the substrate W is separated from the polishing pad 3a under the action of the tension of the diaphragm 13, the diaphragm 13 returns to its original state and the volume of the regions 131 to 138 decreases. Therefore, the flow rate is temporarily negative, and thereafter, the flow rate stabilizes and becomes zero.

In this way, when the adsorption range during lift-off is narrow, the shape of the diaphragm 13 changes, 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, when the top ring 1 starts to rise, the adsorption range is wide. Therefore, the substrate W is less affected by the polishing pad 3a, 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 131-138 is stable, which is 0.

In this way, in the first embodiment, the adsorption range of the substrate W is narrowed during transport before polishing, and the adsorption range of the substrate W is widened during transport after polishing. As a result, the pressure applied to the substrate W can be reduced, the polishing rate can be stabilized, and it can be reliably lifted off. Therefore, the substrate can be properly processed from receiving the substrate W to lift-off, and handling errors such as substrate cracking and other defects, substrate dropping, and failure to pick up the substrate can be suppressed, thereby improving yield and productivity.

In addition, in this embodiment, only the area 134 is decompressed during transportation before polishing, and areas 131 to 135 are decompressed during transportation after polishing. It is sufficient that the adsorption range during transportation before grinding is wide. For example: when transporting before grinding, it is not necessary to decompress the circular area but only the circular area to absorb Substrate W. Specifically, when transporting before polishing, only the area 131 may be decompressed, the areas 131 and 132 may be decompressed, or the areas 131 to 133 may be decompressed. In addition, when transporting after polishing, the area with a wider range of adsorption than when transporting before polishing-for example, the area where the pressure has been reduced during transport before polishing and the area inside and/or outside the reduced pressure area, Just decompress.

<Second Embodiment>

The first embodiment described above is an embodiment in which the adsorption range is widened at the time of lift-off. However, due to different circumstances, sometimes the substrate is deformed due to the widening of the adsorption range, and pressure is 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. This FIG. 11 is a graph measured on 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, that is, the downward direction is positive). As shown in the figure, the outer periphery of the substrate is greatly deformed. In addition, deformation occurred on the outside from a position about 100 mm from the center of the substrate, and pressure was applied to this position.

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

FIG. 12 is a cross-sectional view showing the diaphragm 13. The diaphragm 13 has: 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 contact portion 130 is in contact with and held on the back surface of the substrate W, that is, the surface on the opposite side of the surface to be polished. In addition, the contact portion 130 presses the substrate W against the polishing pad 3a during polishing. The peripheral walls 13a to 13h are ring-shaped peripheral walls arranged concentrically.

The upper end of the peripheral wall 13a~13h is clamped between the retaining ring 22, 24, 26, 27 and the top ring Between the lower surfaces of the main body 11, the top ring main body 11 is installed. These holding rings 22, 24, 26, and 27 are detachably fixed to the top ring main body 11 by a holding 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, and thereby the diaphragm 13 can be detached from the top ring main body 11. As the holding unit, screws or the like can be used.

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

FIG. 13 is an enlarged cross-sectional view showing a part of the diaphragm 13. In order to be able 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 of the contact 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 has an upper inner peripheral surface 1010a and a lower inner peripheral surface 1010b that extend perpendicular to the contact portion 130. The upper inner peripheral surface 1010a extends upward from the horizontal portion 1110 of the second edge peripheral wall 13g, and the lower inner peripheral surface 1010b extends downward from the horizontal portion 1110 of the second edge peripheral wall 13g. In other words, the outer horizontal portion 1110 of the second edge peripheral wall 13g is connected at a position dividing the inner peripheral surface 1010 extending perpendicularly to the contact portion 130. The lower inner peripheral surface 1010b is connected to the terminal portion of the contact portion 130. The outer peripheral surface 1020 located outside the lower inner peripheral surface 1010b also extends perpendicularly to the contact 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 contact 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 peripheral wall 13h has a bending portion that allows the up and down movement of the abutting portion 130 1030. The bent portion 1030 is connected to the upper inner peripheral surface 1010a. The bending portion 1030 has a bellows structure that is configured to expand and contract in a direction perpendicular to the contact portion 130 (that is, the vertical direction). Therefore, even if the distance between the top ring main body 11 and the polishing pad 3a changes, 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 from the upper end of the bent portion 1030 inward in the radial direction. The rim 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 that extends horizontally from the inner peripheral surface 1010 of the first edge peripheral wall 13h. Also, 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 plumb portion 1140. The inclined portion 1120 extends radially inward from the outer horizontal portion 1110 and is inclined upward. The rim 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 edge peripheral wall 13h and the second edge peripheral wall 13g are installed on the lower surface of the top ring main body 11 through the retaining ring 27, a region 138 is formed between the first edge peripheral wall 13h and the second edge peripheral wall 13g.

The third edge peripheral wall 13f is arranged on the radially inner side of the second edge peripheral wall 13g. The third edge 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 plumb part 1230. The inclined portion 1210 extends from the upper surface of the abutting portion 130 inward in the radial direction 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 installed on the lower surface of the top ring main body 11 through the retaining rings 27, 26, then the second edge A region 137 is formed between the peripheral wall 13g and the third edge peripheral wall 13f.

The peripheral wall 13e is arranged on the radially inner side 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 Plumb 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. If the peripheral wall 13e and the third edge peripheral wall 13f are installed 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 the peripheral wall 13e shown in FIG. Therefore, their description is omitted. As shown in FIG. 12, the edges of the peripheral walls 13a and 13b are fixed to the lower surface of the top ring body 11 through the retaining ring 22, and the edges of the peripheral walls 13c and 13d are fixed to the lower surface of the top ring body 11 through the retaining ring 24. In addition, in the areas 131, 133, and 135, rings 21, 23, and 25 protruding from the top ring main body 11 are respectively formed.

In addition, the area 136 formed under the holding ring 26 is narrower than the areas 132 and 134 formed under the holding rings 22 and 24 and the areas 131, 133, and 135 under the rings 21, 23, and 25, respectively.

The top ring 1 in this embodiment has a supporting portion 161 located in the area 136 and extending toward the diaphragm 13. Specifically, the supporting portion 161 extends downward through the space 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 part 1220. In addition, the lower surface of the supporting portion 161 is substantially parallel to the diaphragm 13. The supporting portion 161 is an integral member with the retaining ring 26, and may also be a component from the retaining ring 26. Concentric ring-shaped protrusions on which the holding ring 26 extends.

In addition, the top ring 1 may also have a supporting portion 151 located in the area 134 and extending substantially parallel to the diaphragm 13. The support portion 151 may be a member integrated with the holding ring 24 and may be a concentric ring-shaped protrusion extending from the holding ring 24.

Thus, it is desirable that the lower surface of the holding ring 22, the lower surface of the holding 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 main body 11 of the regions 131, 133, 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 protruding so as not to hinder the vertical and radial extension of the diaphragm 13, but when the area is decompressed to hold the substrate, the vertical direction shape change of the diaphragm 13 is suppressed. As a result, even when a wide area (for example, the above-mentioned areas 131 to 135) is used to adsorb the substrate during the transportation process after polishing, the deformation of the substrate can be suppressed as much as possible, and the substrate can be held flat and uniformly. pressure.

When the substrate is adsorbed by the diaphragm 13, the area 136 corresponds to a portion that abuts the edge of the substrate (within about 20 mm from the periphery of the substrate). In addition, the area 136 is narrower than the inner areas 131 to 135. Generally, in order to improve the edge controllability of the polishing profile, it is difficult to think of providing a support portion in such an area 136. However, in the present embodiment, by deliberately providing the support portion in the region 136 corresponding to the edge of the substrate, it is possible to suppress the deformation of the substrate.

FIG. 14 is a graph in which the amount of deformation of the substrate at the time of lift-off caused by the presence or absence of the support portion was measured. The solid line in FIG. 14 indicates the case where there is a support part. The broken line in FIG. 14 indicates the case where there is no support part, and is the same as that in FIG. As shown in the figure, if the support portion is not provided, the outer peripheral portion of the substrate is greatly deformed, but 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, the support portion is provided in the area. Therefore, even when the substrate is adsorbed in a wide range, the change in the shape of the diaphragm 13 can be suppressed, and the pressure on the substrate can be reduced.

The above-mentioned embodiments are described for the purpose of being able to carry out the present invention by those having ordinary knowledge in the technical field to which the present invention belongs. As long as those skilled in the art can of course complete various modifications of the above-mentioned embodiments, 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 in accordance with the technical idea defined by the scope of the patent application.

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Claims (14)

A method for polishing a substrate, comprising: a conveying step in which a substrate is adsorbed by a first region of an elastic film and the substrate is conveyed to a polishing pad; and a polishing step in which the substrate is combined with The polishing pad contacts and polishes the substrate; and a lift-off step in which a second region of the elastic film that is wider than the first region is used to adsorb the substrate to remove The substrate is lifted off from the polishing pad. A method for polishing a substrate, comprising: a conveying process in which the pressure formed between a top ring main body and an elastic membrane is reduced in a first area in an area (area) where the pressure can be adjusted, thereby utilizing the The lower surface of the elastic film adsorbs the substrate and transports the substrate to the 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 the polishing step In the lift-off step, the pressure is reduced in the second area wider than the first area in the area where the pressure can be adjusted, so that the lower surface of the elastic film is used to adsorb the substrate and remove the substrate from the area. The polishing pad is lifted off. The substrate polishing method according to the second item of the scope of patent application, wherein a plurality of regions whose pressure can be adjusted are formed between the top ring main body and the elastic membrane; the first region includes the plurality of regions The predetermined number of regions in the above; the second region includes regions in the plurality of regions whose number is greater than the predetermined number. According to the method for polishing a substrate according to claim 3, wherein the second area is concentric with the first area, and the second area is wider than the first area. According to the method for polishing a substrate according to claim 3, the first area is a circular or annular area. The substrate polishing method according to any one of claims 2 to 5, wherein in the polishing step, at least a part of the area where the pressure can be adjusted is pressurized. The substrate polishing method according to any one of items 2 to 5 of the scope of patent application, wherein a support portion extending toward the elastic membrane is provided in an area where the pressure can be adjusted. A top ring for holding a substrate. The top ring is provided with: a top ring main body; an elastic membrane disposed below the top ring main body, and a top ring main body is formed between the elastic membrane and the top ring main body. An area where the pressure can be adjusted; a holding member that holds the elastic membrane on the top ring; and a support portion that is provided in the area and extends toward the elastic membrane, the support portion is Concentric annular protrusions extending from the holding member. The top ring according to the eighth patent application, wherein the substrate is adsorbed to the lower surface of the elastic film, and the support portion is provided at a portion corresponding to the edge of the substrate to be adsorbed. The top ring according to claim 8, 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 shape change of the elastic film . The top ring described in item 8 of the scope of patent application includes a retaining ring provided below the top ring main body and around the elastic membrane. The top ring described in item 11 of the scope of patent application, wherein the retaining ring has an inner ring and an outer ring provided on the outer side of the inner ring. A substrate polishing device comprising: the top ring described in the scope of patent application; a polishing pad that contacts a substrate held on the top ring and polishes the substrate; and a pressure control unit, the polishing pad being in contact with a substrate held on the top ring and polishing the substrate; The pressure control unit controls the pressure in the area where the pressure can be adjusted. The substrate polishing device according to claim 13, wherein, when the substrate is transported before polishing the substrate, the pressure control unit reduces the pressure in the first area in the area where the pressure can be adjusted; When the substrate is lifted away from the polishing pad after the substrate is polished, the pressure control unit performs processing on a second region that is wider than the first region among the regions where the pressure can be adjusted. stress reliever.

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