JP5197644B2 - Polishing apparatus and polishing method - Google Patents

Description

  The present invention relates to a polishing apparatus and a polishing method for polishing a substrate such as a semiconductor wafer in a flat and mirror-like shape, and in particular, a substrate holding unit called a top ring or a carrier head and a transfer device including a robot or a transporter. The present invention relates to a polishing apparatus and a polishing method provided with a substrate transfer portion for transferring a substrate between them.

  In recent years, semiconductor devices have become increasingly finer and the element structure has become more complex, and as the number of layers of logic-based multilayer wiring has increased, the unevenness of the surface of the semiconductor device has increased and the level difference has a tendency to increase. This is because, in the manufacture of semiconductor devices, the process of forming a thin film, micropatterning for patterning and opening and then forming the next thin film is repeated many times.

  If the irregularities on the surface of the semiconductor device increase, the film thickness at the stepped part will become thinner during thin film formation, open due to disconnection of the wiring, short circuit due to insulation failure between wiring layers, etc. There is a tendency to decrease. In addition, even if the device normally operates normally at the beginning, a problem of reliability occurs for a long time use. Furthermore, if the irradiation surface has irregularities at the time of exposure in the lithography process, the lens focus of the exposure system becomes partially unfocused. Therefore, if the irregularities on the surface of the semiconductor device increase, it becomes difficult to form a fine pattern itself.

Accordingly, in the semiconductor device manufacturing process, a planarization technique for the surface of the semiconductor device is becoming increasingly important. Among the planarization techniques, the most important technique is chemical mechanical polishing (CMP). This chemical mechanical polishing uses a polishing apparatus to slide a substrate such as a semiconductor wafer onto the polishing surface while supplying a polishing liquid containing abrasive grains such as silica (SiO ₂ ) onto the polishing surface such as a polishing pad. Polishing in contact.

  This type of polishing apparatus includes a polishing table having a polishing surface made of a polishing pad, and a substrate holding unit called a top ring or a carrier head for holding a semiconductor wafer. When polishing a semiconductor wafer using such a polishing apparatus, the semiconductor wafer is pressed against the polishing table with a predetermined pressure while the semiconductor wafer is held by the substrate holder. At this time, by moving the polishing table and the substrate holding portion relative to each other, the semiconductor wafer comes into sliding contact with the polishing surface, and the surface of the semiconductor wafer is polished to a flat and mirror surface.

  In such a polishing apparatus, when the relative pressing force between the semiconductor wafer being polished and the polishing surface of the polishing pad is not uniform over the entire surface of the semiconductor wafer, it is applied to each part of the semiconductor wafer. Depending on the pressing force, insufficient polishing or overpolishing occurs. Therefore, the holding surface of the semiconductor wafer of the substrate holding part is formed with a membrane made of an elastic material such as rubber, and fluid pressure such as air pressure is applied to the back surface of the membrane so that the pressing force applied to the semiconductor wafer is made uniform over the entire surface. It has also been done.

  When the semiconductor wafer before polishing is transferred to the substrate holding unit and the semiconductor wafer after polishing is received directly from the substrate holding unit by a transfer device such as a robot, there is a risk of making a transfer mistake due to variations in transfer accuracy between the two. is there. For this reason, a substrate transfer portion called a pusher is installed at a position where the semiconductor wafer is transferred to the substrate holding portion or a position where the semiconductor wafer is transferred from the substrate holding portion. The substrate transfer unit temporarily places a semiconductor wafer transferred by a transfer device such as a robot on the substrate transfer unit, and then moves the semiconductor wafer against a substrate holding unit such as a top ring that has moved above the substrate transfer unit. Is a device that has a function of lifting the wafer and delivering the semiconductor wafer to the substrate holding unit, and a function of delivering the semiconductor wafer received from the substrate holding unit to a transfer device such as a robot.

  When a substrate such as a semiconductor wafer is transferred from the substrate holding unit such as the top ring to the pusher (substrate transfer unit), a pressurized fluid (gas, liquid, or gas and liquid is supplied to the fluid path provided in the top ring. A mixed fluid) is introduced, and the semiconductor wafer is pushed out of the top ring and separated from the top ring. At that time, a certain gap is provided between the top ring and the pusher. When the semiconductor wafer is detached from the top ring, the semiconductor wafer falls by the gap, and the pusher removes the dropped semiconductor wafer. It has a structure to accept.

  In the polishing apparatus described above, the type of slurry (polishing liquid), the polishing time, the pressing force of the semiconductor wafer, the rotation speed of the top ring and the polishing table are set to various polishing conditions, and the semiconductor wafer is polished. It has been broken. Depending on the conditions at the time of polishing, there is a problem that when the semiconductor wafer is detached from the top ring after the polishing, the semiconductor wafer strongly sticks to the top ring and cannot be detached. In particular, in the membrane type substrate holder that forms the holding surface of the semiconductor wafer with a membrane, applies fluid pressure such as air pressure to the back surface of the membrane, and presses the semiconductor wafer against the polishing surface on the polishing table, the material of the membrane Since rubber is used, when the semiconductor wafer is removed after polishing, the semiconductor wafer will stick to the membrane strongly and will not peel off, or it will take some time to peel it off, or part of the semiconductor wafer will remain in the membrane. There is a problem such as falling diagonally while sticking to. In this case, when the pressure of the pressurized fluid ejected from the top ring is increased in order to surely peel off the semiconductor wafer from the top ring, the pressure of the pressurized fluid causes the semiconductor wafer to drop toward the pusher vigorously. Has the problem of cracking or damage.

In recent years, low-k materials having a low dielectric constant are being developed as interlayer insulating films instead of SiO ₂ . However, when such a low dielectric constant low-k material is used, the low-k material has the disadvantage that its mechanical properties are weak and it is easily destroyed. Therefore, when the method is such that the pressurized wafer is ejected and the semiconductor wafer is peeled off from the top ring as described above, the low-k material is destroyed by the impact of dropping when the semiconductor wafer is detached, and the yield is reduced. The problem of doing becomes remarkable.

  The present invention has been made in view of the above-described conventional problems, and after the polishing of a substrate such as a semiconductor wafer is completed, the substrate can be quickly and reliably detached from the substrate holding portion such as a top ring. An object of the present invention is to provide a polishing apparatus and a polishing method that can be safely detached without excessive pressure being applied to the substrate sometimes and that does not give an impact to the substrate when it is transferred to the substrate transfer section.

In order to achieve the above object, a polishing apparatus according to the present invention includes a substrate holding unit that holds a substrate, a substrate placement unit that places a substrate, and a substrate transfer unit that includes a lift unit that raises and lowers the substrate placement unit. The substrate transfer portion includes a peripheral portion of the substrate held by the substrate holding portion and the substrate holding portion in accordance with the swing of the link supported so as to be swingable via a pin. The tapered tip of the link is inserted into the gap formed between the two, and the link is further swung while the tapered tip is brought into contact with the peripheral edge of the substrate to move the substrate away from the substrate holding portion. to have peeled off chuck mechanism before Symbol substrate holder Te you characterized.

According to the polishing apparatus of the present invention, when the substrate is transferred from the substrate holding unit to the substrate transfer unit, the tapered tip of the link is inserted between the substrate holding surface of the substrate holding unit and the substrate to hold the substrate. It can be forcibly removed from the part.

  According to an aspect of the present invention, the substrate holding unit may be configured such that when the substrate is transferred from the substrate holding unit to the substrate mounting unit, the substrate holding unit has a contact surface that contacts the substrate of the substrate holding unit. Supply pressurized fluid.

  According to an aspect of the present invention, the substrate holding unit includes: a substrate holding unit main body that holds the substrate; an elastic pad that has an abutting surface that contacts the substrate; and a support member that supports the elastic pad. The elastic pad has an opening, and has a supply source for supplying a fluid or a vacuum to the opening.

  According to an aspect of the present invention, a contact member having an elastic film that contacts the elastic pad is attached to a lower surface of the support member, and the space is formed between the elastic pad and the support member. Has a first pressure chamber formed inside the contact member and a second pressure chamber formed outside the contact member, and is disposed between the substrate holding body and the support member. The space to be formed has a third pressure chamber, and the supply source includes a first pressure chamber formed inside the contact member and a second pressure formed outside the contact member. It is possible to independently supply a fluid or a vacuum to the chamber and the third pressure chamber, respectively.

The polishing method of the present invention polishes the substrate held while being brought into contact with the elastic pad of the substrate holding portion, and after the polishing is completed, the elastic pad is expanded and the peripheral portion of the substrate held by the substrate holding portion and the elastic pad Forming a gap between them, and swinging a link supported so as to be swingable via a pin in the substrate transfer section so that the tapered tip of the link enters the gap, and the tapered tip is inserted into the peripheral edge of the substrate. the substrate is further swung the link while contact is moved in a direction away from said resilient pad, characterized in that away from said resilient pad.

  According to the present invention, after polishing of a substrate such as a semiconductor wafer, the substrate can be quickly and surely detached from the substrate holder such as a top ring, and no excessive pressure is applied to the substrate at the time of separation. The substrate is safely detached and does not give an impact to the substrate when it is transferred to the substrate transfer section. Accordingly, the yield is improved without the substrate being cracked or damaged. Further, since the substrate can be quickly detached from the substrate holding portion, the throughput is improved. Further, since the impact is reduced when the substrate is transferred to the substrate transfer portion, the yield is remarkably improved in the process using the low-k material.

It is sectional drawing which shows the whole structure of a grinding | polishing apparatus. It is a longitudinal cross-sectional view which shows a top ring. FIG. 3 is a bottom view of the top ring shown in FIG. 2. It is a perspective view which shows the relationship between a pusher, a top ring, and a linear transporter. It is a longitudinal cross-sectional view which shows the detailed structure of a pusher. FIGS. 6A to 6E are diagrams for explaining the operation of the pusher. It is a typical sectional view showing other pushers. It is a schematic sectional drawing which shows the detailed structure of a suction pad. FIGS. 9A to 9D are diagrams for explaining the operation of the pusher shown in FIG. It is a typical sectional view showing other pushers. FIG. 11A to FIG. 11F are diagrams for explaining the operation of the pusher shown in FIG. It is a typical sectional view showing other pushers. FIGS. 13A to 13C are diagrams for explaining the operation of the pusher shown in FIG. It is typical sectional drawing which shows the pusher used for the grinding | polishing apparatus of embodiment of this invention. FIGS. 15A and 15B are diagrams for explaining the operation of the pusher shown in FIG. It is a typical sectional view showing other pushers. FIGS. 17A to 17C are diagrams for explaining the operation of the pusher shown in FIG. It is a typical sectional view showing other pushers. FIGS. 19A and 19B are diagrams for explaining the operation of the pusher shown in FIG.

Hereinafter, a polishing apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing the overall configuration of the polishing apparatus. As shown in FIG. 1, a polishing table 100 having a polishing pad 101 attached to the upper surface is installed below the top ring 1 constituting the substrate holding unit. A polishing liquid supply nozzle 102 is installed above the polishing table 100, and the polishing liquid Q is supplied onto the polishing pad 101 on the polishing table 100 by the polishing liquid supply nozzle 102.

  There are various types of polishing pads available on the market, such as SUBA800, IC-1000, IC-1000 / SUBA400 (double-layer cloth) manufactured by Rodel, Surfin xxx-5 manufactured by Fujimi Incorporated, Surfin 000 etc. SUBA800, Surfin xxx-5, and Surfin 000 are non-woven fabrics in which fibers are hardened with urethane resin, and IC-1000 is a hard foamed polyurethane (single layer). The polyurethane foam is porous (porous) and has a large number of fine dents or pores on its surface.

The polishing surface is not limited to the above-described polishing pad, and the polishing surface may be formed by, for example, fixed abrasive grains. The fixed abrasive is a plate formed by fixing abrasive in a binder. In polishing using fixed abrasive grains, polishing proceeds by abrasive grains spontaneously generated from the fixed abrasive grains. The fixed abrasive is composed of abrasive grains, a binder, and pores. For example, CeO ₂ or SiO ₂ or Al ₂ O ₃ having an average particle diameter of 0.5 μm or less is used for the abrasive grains, and an epoxy resin or a phenol resin is used for the binder. Or a thermoplastic resin such as MBS resin or ABS resin. Such fixed abrasive grains constitute a hard polishing surface. The fixed abrasive also includes a fixed abrasive pad having a two-layer structure in which a polishing pad having elasticity is stuck under a thin fixed abrasive layer in addition to the plate-like one described above.

  The top ring 1 is connected to a top ring drive shaft 11 via a universal joint portion 10, and the top ring drive shaft 11 is connected to a top ring air cylinder 111 fixed to a top ring head 110. The top ring drive shaft 11 is moved up and down by the top ring air cylinder 111 to move the entire top ring 1 up and down and press the retainer ring 3 fixed to the lower end of the top ring body 2 against the polishing table 100. ing. The top ring air cylinder 111 is connected to the compressed air source 120 via the regulator R1, and the pressure of the pressurized air supplied to the top ring air cylinder 111 can be adjusted by the regulator R1. Thereby, the pressing force with which the retainer ring 3 presses the polishing pad 101 can be adjusted.

  The top ring drive shaft 11 is connected to the rotary cylinder 112 through a key (not shown). The rotating cylinder 112 includes a timing pulley 113 on the outer periphery thereof. A top ring motor 114 is fixed to the top ring head 110, and the timing pulley 113 is connected to a timing pulley 116 provided on the top ring motor 114 via a timing belt 115. Accordingly, when the top ring motor 114 is rotationally driven, the rotary cylinder 112 and the top ring drive shaft 11 are integrally rotated via the timing pulley 116, the timing belt 115, and the timing pulley 113, and the top ring 1 is rotated. The top ring head 110 is supported by a top ring head shaft 117 fixedly supported on a frame (not shown). The top ring shaft head 117 is rotatable, and the top ring 1 swings between a polishing position on the polishing table 100 and a pusher (described later).

Hereinafter, the top ring 1 constituting the substrate holding portion will be described in more detail.
2 is a longitudinal sectional view showing the top ring 1, and FIG. 3 is a bottom view of the top ring 1 shown in FIG.
As shown in FIG. 2, the top ring 1 constituting the substrate holding portion includes a cylindrical container-shaped top ring body 2 having an accommodating space therein, and a retainer ring 3 fixed to the lower end of the top ring body 2. ing. The top ring body 2 is made of a material having high strength and rigidity such as metal and ceramics. The retainer ring 3 is made of a highly rigid resin material or ceramics.

  The top ring body 2 is fitted to a cylindrical container-like housing part 2a, an annular pressure sheet support part 2b fitted inside the cylindrical part of the housing part 2a, and an outer peripheral edge part on the upper surface of the housing part 2a. And an annular seal portion 2c. A retainer ring 3 is fixed to the lower end of the housing portion 2a of the top ring body 2. The lower part of the retainer ring 3 protrudes inward. The retainer ring 3 may be formed integrally with the top ring main body 2.

  The above-described top ring drive shaft 11 is disposed above the central portion of the housing portion 2a of the top ring main body 2. The top ring main body 2 and the top ring drive shaft 11 are connected by a universal joint portion 10. Yes. The universal joint portion 10 includes a spherical bearing mechanism that allows the top ring body 2 and the top ring drive shaft 11 to tilt relative to each other, and a rotation transmission mechanism that transmits the rotation of the top ring drive shaft 11 to the top ring body 2. The top ring drive shaft 11 transmits the pressing force and the rotational force while allowing the tilting of the top ring body 2.

  The spherical bearing mechanism includes a spherical recess 11a formed at the center of the lower surface of the top ring drive shaft 11, a spherical recess 2d formed at the center of the upper surface of the housing portion 2a, and an intervening space between the recesses 11a and 2d. And a bearing ball 12 made of a high hardness material such as ceramic. On the other hand, the rotation transmission mechanism includes a drive pin (not shown) fixed to the top ring drive shaft 11 and a driven pin (not shown) fixed to the housing portion 2a. Even if the top ring main body 2 is tilted, the driven pin and the driving pin can move relatively in the vertical direction, so that they engage with each other by shifting their contact points, and the rotation transmission mechanism rotates the top ring driving shaft 11. Torque is reliably transmitted to the top ring body 2.

  In the space defined inside the top ring body 2 and the retainer ring 3 fixed integrally to the top ring body 2, there is an elastic pad (membrane) 4 that contacts the semiconductor wafer W held by the top ring 1. An annular holder ring 5 and a substantially disc-shaped subcarrier plate 6 (support member) for supporting the elastic pad 4 are accommodated. The outer periphery of the elastic pad 4 is sandwiched between the holder ring 5 and the subcarrier plate 6 fixed to the lower end of the holder ring 5, and covers the lower surface of the subcarrier plate 6. Thereby, a space is formed between the elastic pad 4 and the subcarrier plate 6.

  The subcarrier plate 6 may be made of a metal material, but a thin film formed on the surface of the semiconductor wafer to be polished by a film thickness measuring method using an eddy current in a state where the semiconductor wafer to be polished is held on the top ring. In the case of measuring the film thickness, it is preferable that the film is made of a non-magnetic material, for example, an insulating material such as a fluorine-based resin or ceramics.

  A pressure sheet 7 made of an elastic film is stretched between the holder ring 5 and the top ring body 2. One end of the pressure sheet 7 is sandwiched between the housing portion 2a of the top ring body 2 and the pressure sheet support portion 2b, and the other end is sandwiched between the upper end portion 5a of the holder ring 5 and the stopper portion 5b. It is fixed. A pressure chamber 21 (third pressure chamber) is formed inside the top ring body 2 by the top ring body 2, the subcarrier plate 6, the holder ring 5, and the pressure sheet 7. A fluid passage 31 including a tube, a connector, and the like communicates with the pressure chamber 21, and the pressure chamber 21 is connected to a compressed air source 120 via a regulator R 2 disposed on the fluid passage 31 as shown in FIG. Has been. The pressure sheet 7 is formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber.

  In the case where the pressure sheet 7 is an elastic body such as rubber, when the pressure sheet 7 is sandwiched and fixed between the retainer ring 3 and the top ring body 2, the pressure sheet 7 as an elastic body. Due to the elastic deformation, a preferable plane cannot be obtained on the lower surface of the retainer ring 3. Therefore, in order to prevent this, in this example, a pressure sheet support portion 2b is provided as a separate member, and is sandwiched and fixed between the housing portion 2a of the top ring body 2 and the pressure sheet support portion 2b. Yes. As described in Japanese Patent Application No. 8-50956 (Japanese Patent Application Laid-Open No. 9-168964) and Japanese Patent Application No. 11-294503, the retainer ring 3 can be moved up and down with respect to the top ring body 2, or the retainer ring 3 Can be made a structure that can be pressed independently of the top ring main body 2. In such a case, the above-described fixing method of the pressure sheet 7 is not necessarily used.

  In the vicinity of the outer peripheral edge of the upper surface of the housing portion 2a to which the seal portion 2c of the top ring body 2 is fitted, a cleaning liquid path 51 formed of an annular groove is formed. The cleaning liquid path 51 communicates with the fluid path 32 through the through hole 52 of the seal portion 2 c, and the cleaning liquid (pure water) is supplied through the fluid path 32. Further, a plurality of communication holes 53 are provided from the cleaning liquid passage 51 through the housing part 2 a and the pressure sheet support part 2 b, and the communication holes 53 are slightly formed between the outer peripheral surface of the elastic pad 4 and the retainer ring 3. The gap G is communicated.

  In a space formed between the elastic pad 4 and the subcarrier plate 6, a center bag 8 (center contact member) as a contact member that contacts the elastic pad 4 and a ring tube 9 (outer contact). Member). In this example, as shown in FIG. 2 and FIG. 3, the center bag 8 is disposed at the center of the lower surface of the subcarrier plate 6, and the ring tube 9 surrounds the periphery of the center bag 8. Arranged outside. The elastic pad 4, the center bag 8, and the ring tube 9 are formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM), polyurethane rubber, and silicon rubber, like the pressure sheet 7. Yes.

  The space formed between the subcarrier plate 6 and the elastic pad 4 is partitioned into a plurality of spaces (second pressure chambers) by the center bag 8 and the ring tube 9, thereby the center bag 8 and the ring. A pressure chamber 22 is formed between the tubes 9, and a pressure chamber 23 is formed outside the ring tube 9.

  The center bag 8 includes an elastic film 81 that contacts the upper surface of the elastic pad 4 and a center bag holder 82 (holding portion) that holds the elastic film 81 in a detachable manner. A screw hole 82a is formed in the center bag holder 82, and the center bag 8 is detachably attached to the center of the lower surface of the subcarrier plate 6 by screwing a screw 55 into the screw hole 82a. . Inside the center bag 8, the central pressure chamber 24 (first pressure chamber) is formed by the elastic film 81 and the center bag holder 82.

  Similarly, the ring tube 9 includes an elastic film 91 that contacts the upper surface of the elastic pad 4 and a ring tube holder 92 (holding part) that holds the elastic film 91 in a detachable manner. A screw hole 92 a is formed in the ring tube holder 92, and the ring tube 9 is detachably attached to the lower surface of the subcarrier plate 6 by screwing a screw 56 into the screw hole 92 a. An intermediate pressure chamber 25 (first pressure chamber) is formed inside the ring tube 9 by the elastic membrane 91 and the ring tube holder 92.

  Fluid passages 33, 34, 35, and 36 including tubes, connectors, and the like are communicated with the pressure chambers 22, 23, the central pressure chamber 24, and the intermediate pressure chamber 25, respectively. The pressure chambers 22 to 25 are connected to a compressed air source 120 as a supply source via regulators R3, R4, R5, and R6 disposed on the fluid passages 33 to 36, respectively. The fluid paths 31 to 36 are connected to the regulators R1 to R6 via a rotary joint (not shown) provided at the upper end of the top ring shaft 110.

  The pressure chamber 21 and the pressure chambers 22 to 25 above the subcarrier plate 6 are pressurized with pressurized air or the like via fluid passages 31, 33, 34, 35, and 36 communicated with the pressure chambers. Fluid, atmospheric pressure or vacuum is supplied. As shown in FIG. 1, the pressure of the pressurized fluid supplied to each pressure chamber is adjusted by regulators R2 to R6 arranged on the fluid passages 31, 33, 34, 35, and 36 of the pressure chambers 21 to 25. be able to. Thereby, the pressure inside each pressure chamber 21-25 can be controlled independently, respectively, or it can be made atmospheric pressure or a vacuum. Thus, by making the internal pressures of the pressure chambers 21 to 25 variable independently by the regulators R2 to R6, the pressing force for pressing the semiconductor wafer W against the polishing pad 101 via the elastic pad 4 is changed. Can be adjusted for each part. In some cases, these pressure chambers 21 to 25 may be connected to the vacuum source 121.

  In this case, it is good also as controlling the temperature of the pressurized fluid and atmospheric pressure which are supplied to each pressure chamber 22-25. In this way, the temperature of the polishing object can be directly controlled from the back side of the surface to be polished of the polishing object such as a semiconductor wafer. In particular, if the temperature of each pressure chamber is controlled independently, the chemical reaction rate of chemical polishing in CMP can be controlled.

  The elastic pad 4 is provided with a plurality of openings 41 as shown in FIG. An inner periphery adsorbing portion 61 that protrudes downward from the subcarrier plate 6 is provided so as to be exposed from the opening 41 between the center bag 8 and the ring tube 9. An outer peripheral suction part 62 is provided so as to be exposed from the opening 41. In this example, the elastic pad 4 is provided with eight openings 41 so that the suction portions 61 and 62 are exposed in each opening 41.

  The inner periphery suction portion 61 and the outer periphery suction portion 62 are respectively formed with communication holes 61a and 62a communicating with the fluid paths 37 and 38, respectively. The inner periphery suction portion 61 and the outer periphery suction portion 62 are fluids. It is connected to a vacuum source 121 such as a vacuum pump through passages 37 and 38 and valves V1 and V2. And when the communication holes 61a and 62a of the inner peripheral part adsorption | suction part 61 and the outer peripheral part adsorption | suction part 62 are connected to the vacuum source 121, a negative pressure will be formed in the opening end of the communication holes 61a and 62a, and inner peripheral part adsorption | suction part The semiconductor wafer W is adsorbed by 61 and the outer periphery adsorbing part 62. In addition, elastic sheets 61b and 62b made of a thin rubber sheet or the like are attached to the lower end surfaces of the inner periphery suction portion 61 and the outer periphery suction portion 62, and the inner periphery suction portion 61 and the outer periphery suction portion 62 are The semiconductor wafer W is adsorbed and held flexibly.

  Further, as shown in FIG. 2, during polishing of the semiconductor wafer W, the inner periphery suction portion 61 and the outer periphery suction portion 62 are located above the lower end surface of the elastic pad 4, and the lower end surface of the elastic pad 4. There is no more protrusion. When adsorbing the semiconductor wafer W, the lower end surfaces of the inner periphery adsorbing portion 61 and the outer periphery adsorbing portion 62 are substantially flush with the lower end surface of the elastic pad 4.

  Here, since there is a slight gap G between the outer peripheral surface of the elastic pad 4 and the retainer ring 3, a member such as the holder ring 5, the subcarrier plate 6, and the elastic pad 4 attached to the subcarrier plate 6. Is movable in the vertical direction with respect to the top ring body 2 and the retainer ring 3 and has a floating structure. The stopper portion 5b of the holder ring 5 is provided with a plurality of protrusions 5c protruding outward from the outer peripheral edge thereof, and the protrusions 5c are related to the upper surface of the portion protruding inward of the retainer ring 3. By combining, the downward movement of the member such as the holder ring 5 is limited to a predetermined position.

Next, the operation of the top ring 1 configured as described above will be described in detail.
In the polishing apparatus having the above-described configuration, when the semiconductor wafer W is transferred, the entire top ring 1 is positioned at a pusher (described later), and the communication holes 61 a and 62 a of the inner periphery suction portion 61 and the outer periphery suction portion 62 are formed. It is connected to the vacuum source 121 via fluid paths 37 and 38. The semiconductor wafer W is vacuum-sucked to the lower end surfaces of the inner periphery suction portion 61 and the outer periphery suction portion 62 by the suction action of the communication holes 61a and 62a. Then, the top ring 1 is moved in a state where the semiconductor wafer W is attracted, and the entire top ring 1 is positioned above the polishing table 100 having the polishing surface (polishing pad 101). The outer peripheral edge of the semiconductor wafer W is held by the retainer ring 3 so that the semiconductor wafer W does not jump out of the top ring 1.

  At the time of polishing, the suction of the semiconductor wafer W by the suction portions 61 and 62 is released, the semiconductor wafer W is held on the lower surface of the top ring 1, and the top ring air cylinder 111 connected to the top ring drive shaft 11 is operated. Then, the retainer ring 3 fixed to the lower end of the top ring 1 is pressed against the polishing surface of the polishing table 100 with a predetermined pressing force. In this state, a pressurized fluid having a predetermined pressure is supplied to each of the pressure chambers 22 and 23, the central pressure chamber 24, and the intermediate pressure chamber 25 to press the semiconductor wafer W against the polishing surface of the polishing table 100. Then, by flowing the polishing liquid Q from the polishing liquid supply nozzle 102, the polishing liquid Q is held on the polishing pad 101, and the polishing liquid Q is interposed between the surface (lower surface) of the semiconductor wafer W to be polished and the polishing pad 101. Polishing is performed in the existing state.

  Here, the portions of the semiconductor wafer W positioned below the pressure chambers 22 and 23 are pressed against the polishing surface by the pressure of the pressurized fluid supplied to the pressure chambers 22 and 23, respectively. A portion of the semiconductor wafer W positioned below the central pressure chamber 24 is polished by the pressure of the pressurized fluid supplied to the central pressure chamber 24 through the elastic film 81 and the elastic pad 4 of the center bag 8. Pressed against the surface. A portion of the semiconductor wafer W positioned below the intermediate pressure chamber 25 is applied to the polishing surface by the pressure of the pressurized fluid supplied to the intermediate pressure chamber 25 via the elastic film 91 and the elastic pad 4 of the ring tube 9. Pressed.

  Therefore, the polishing pressure applied to the semiconductor wafer W can be adjusted for each portion of the semiconductor wafer W by controlling the pressure of the pressurized fluid supplied to each pressure chamber 22-25. That is, the pressures of the pressurized fluid supplied to the pressure chambers 22 to 25 by the regulators R3 to R6 are independently adjusted, and the pressing force for pressing the semiconductor wafer W against the polishing pad 101 on the polishing table 100 is set to the semiconductor wafer W. It is adjusted for each part. Thus, the semiconductor wafer W is pressed against the polishing pad 101 on the upper surface of the rotating polishing table 100 in a state where the polishing pressure is adjusted to a desired value for each portion of the semiconductor wafer W. Similarly, the pressure of the pressurized fluid supplied to the top ring air cylinder 111 by the regulator R1 can be adjusted, and the pressing force with which the retainer ring 3 presses the polishing pad 101 can be changed. As described above, by appropriately adjusting the pressing force by which the retainer ring 3 presses the polishing pad 101 and the pressing force by which the semiconductor wafer W is pressed against the polishing pad 101 during polishing, the central portion of the semiconductor wafer W (in FIG. 3). C1), distribution of polishing pressure in each part from the central part to the intermediate part (C2), the intermediate part (C3), the peripheral part (C4), and further to the outer peripheral part of the retainer ring 3 outside the semiconductor wafer W. A desired distribution can be obtained.

  It should be noted that the portion of the semiconductor wafer W located below the pressure chambers 22 and 23 has a pressure of pressurized fluid, such as a portion to which a pressing force is applied from the fluid via the elastic pad 4 and a location of the opening 41. Although there are portions that themselves are applied to the semiconductor wafer W, the pressing force applied to these portions is the same pressure. Further, at the time of polishing, since the elastic pad 4 is in close contact with the back surface of the semiconductor wafer W around the opening 41, the pressurized fluid inside the pressure chambers 22 and 23 hardly leaks to the outside.

  Thus, the semiconductor wafer W can be divided into four concentric circles and ring parts (C1 to C4), and each part can be pressed with an independent pressing force. Although the polishing rate depends on the pressing force on the polishing surface of the semiconductor wafer W, since the pressing force of each part can be controlled as described above, the polishing rate of the four parts (C1 to C4) of the semiconductor wafer W is adjusted. It can be controlled independently. Therefore, even if the film thickness of the thin film to be polished on the surface of the semiconductor wafer W has a radial distribution, it is possible to eliminate insufficient polishing and overpolishing over the entire surface of the semiconductor wafer. That is, even if the thin film to be polished on the surface of the semiconductor wafer W has a different thickness depending on the position in the radial direction of the semiconductor wafer W, the surface of the semiconductor wafer W among the pressure chambers 22 to 25 described above. The pressure of the pressure chamber located above the thick part of the semiconductor wafer W is made higher than the pressure of the other pressure chambers, or the pressure chamber located above the thin part of the surface of the semiconductor wafer W By making the pressure lower than the pressure in the other pressure chambers, it is possible to make the pressing force on the polishing surface of the thick part thicker than the pressing force on the polishing surface of the thin part. The polishing rate can be selectively increased. Thus, it is possible to polish the entire surface of the semiconductor wafer W without excess or deficiency without depending on the film thickness distribution at the time of film formation.

  Edge drooping that occurs at the peripheral edge of the semiconductor wafer W can be prevented by controlling the pressing force of the retainer ring 3. If there is a large change in the film thickness of the thin film to be polished at the peripheral edge of the semiconductor wafer W, the peripheral edge of the semiconductor wafer W can be increased by intentionally increasing or decreasing the pressing force of the retainer ring 3. The polishing rate can be controlled. When the pressurized fluid is supplied to each of the pressure chambers 22 to 25, the subcarrier plate 6 receives an upward force. In this example, the pressurized fluid is supplied to the pressure chamber 21 via the fluid path 31. The subcarrier plate 6 is prevented from being lifted upward by the force from each pressure chamber 22-25.

  As described above, the pressing force of the retainer ring 3 to the polishing pad 101 by the top ring air cylinder 111 and the polishing pad 101 for each portion of the semiconductor wafer W by the pressurized air supplied to the pressure chambers 22 to 25 are applied. The semiconductor wafer W is polished by appropriately adjusting the pressing force. When the polishing is completed, the semiconductor wafer W is again vacuum-sucked to the lower end surfaces of the inner periphery suction portion 61 and the outer periphery suction portion 62. At this time, the supply of the pressurized fluid to the pressure chambers 22 to 25 that press the semiconductor wafer W against the polishing surface is stopped and the pressure is released to the atmospheric pressure, whereby the inner periphery suction portion 61 and the outer periphery suction portion 62. Is brought into contact with the semiconductor wafer W. Further, the pressure in the pressure chamber 21 is released to atmospheric pressure or negative pressure. This is because, if the pressure in the pressure chamber 21 is kept high, only the portion of the semiconductor wafer W that is in contact with the inner periphery suction portion 61 and the outer periphery suction portion 62 is strongly pressed against the polishing surface. This is because it becomes. Therefore, it is necessary to quickly reduce the pressure in the pressure chamber 21, and as shown in FIG. 2, a relief port 39 is provided so as to penetrate the top ring body 2 from the pressure chamber 21, so that the pressure in the pressure chamber 21 decreases quickly. You may do it. In this case, when applying pressure to the pressure chamber 21, it is necessary to always supply the pressure fluid from the fluid path 31. In addition, the relief port 39 includes a check valve so that outside air does not enter the pressure chamber 21 when the pressure chamber 21 is set to a negative pressure.

  After adsorbing the semiconductor wafer W as described above, the entire top ring 1 is positioned at the transfer position of the semiconductor wafer, and the semiconductor wafer W is communicated from the communication holes 61a and 62a of the inner peripheral portion adsorbing portion 61 and the outer peripheral portion adsorbing portion 62. The semiconductor wafer W is released by spraying a fluid (for example, a mixture of compressed air or nitrogen and pure water).

  By the way, the polishing liquid Q used for polishing enters the slight gap G between the outer peripheral surface of the elastic pad 4 and the retainer ring 3, and when this polishing liquid Q is fixed, the holder ring 5 and the sub ring Smooth vertical movement of members such as the carrier plate 6 and the elastic pad 4 with respect to the top ring body 2 and the retainer ring 3 is hindered. Therefore, the cleaning liquid (pure water) is supplied to the cleaning liquid path 51 via the fluid path 32. As a result, pure water is supplied above the gap G from the plurality of communication holes 53, and the pure water is washed away from the gap G to prevent the above-described polishing liquid Q from sticking. This supply of pure water is preferably performed during the period from when the polished semiconductor wafer is released until the next polished semiconductor wafer is adsorbed. Moreover, it is preferable to provide the retainer ring 3 with a plurality of through holes 3a as shown in FIG. 2 so that all the pure water supplied until the next polishing is discharged to the outside. Furthermore, if the pressure is accumulated in the space 26 formed by the retainer ring 3, the holder ring 5, and the pressure sheet 7, the subcarrier plate 6 is prevented from rising, so that the subcarrier plate 6 can be smoothly moved. In order to raise, it is preferable to provide the through hole 3a and make the space 26 have the same pressure as the atmosphere.

  As described above, the pressure on the semiconductor wafer is controlled by independently controlling the pressure in the pressure chambers 22, 23, the pressure chamber 24 in the center bag 8, and the pressure chamber 25 in the ring tube 9. Can do. Furthermore, according to this example, by changing the positions and sizes of the center bag 8 and the ring tube 9, the range for controlling the pressing force can be easily changed.

  Next, a pusher 130 that constitutes a substrate transfer unit for transferring a semiconductor wafer between the top ring and the linear transporter will be described. FIG. 4 is a perspective view showing the relationship among the pusher, the top ring, and the linear transporter. The pusher 130 delivers the semiconductor wafer on the first transfer stage TS1 of the linear transporter 105 to the top ring 1 of the polishing unit, and transfers the semiconductor wafer after polishing on the polishing table 100 of the polishing unit from the top ring 1 to the linear transporter. 105 is transferred to the second transfer stage TS2. Thus, the pusher 130 functions as a delivery mechanism that delivers the semiconductor wafer between the linear transporter 105 and the top ring 1.

  FIG. 5 is a longitudinal sectional view showing the detailed structure of the pusher 130. As shown in FIG. 5, the pusher 130 has a guide stage 131 for holding the top ring on the extension of the hollow shaft 160, a spline shaft 132 passing through the hollow shaft 160, and an extension of the spline shaft 132. And a push stage 133 on which the semiconductor wafer is placed and held. The push stage 133 constitutes a substrate placement unit. Air cylinders 135 and 136 are connected to the spline shaft 132 by a floating joint 134 that can flexibly connect the shaft to the shaft blur. Two air cylinders are arranged vertically in series. The air cylinder 136 arranged at the lowermost stage is for raising / lowering the guide stage 131 and for raising / lowering the push stage 133, and moves the hollow shaft 160 together with the air cylinder 135. The air cylinder 135 is for ascending / descending the push stage 133, and constitutes an elevating unit that elevates and lowers the substrate placement unit.

  Four top ring guides 137 are installed on the outermost periphery of the guide stage 131. The top ring guide 137 has a two-step staircase structure having an upper step portion 138 and a lower step portion 139. The upper stage 138 of the top ring guide 137 is an access part to the lower surface of the guide ring 157 (see FIG. 6) of the top ring, and the lower stage 139 is for centering and holding the semiconductor wafer. A taper 138a (preferably about 25 ° to 35 °) for introducing a top ring is formed on the upper step portion 138, and a taper 139a (10 ° to 20 ° for introducing a semiconductor wafer) is formed on the lower step portion 139. Is preferred). When the wafer is unloaded, the wafer edge is directly received by the top ring guide 137.

  A guide sleeve 140 having a waterproof function and a guide function for returning the raised stage to its original position is installed on the back surface of the guide stage 131. A center sleeve 141 for centering the pusher is fixed to the bearing case 142 inside the guide sleeve 140. The pusher 130 is fixed to the motor housing 143 on the polishing portion side in the bearing case 142.

  A V-ring 144 is used for waterproofing between the push stage 133 and the guide stage 131, and the lip portion of the V-ring 144 is in contact with the guide stage 131 to prevent water from entering inside. When the guide stage 131 rises, the volume of the G part increases, and the pressure drops and sucks water. In order to prevent this, a hole 145 is provided inside the V ring 144 to prevent the pressure from dropping.

  In order to provide the top ring guide 137 with an alignment mechanism, a linear way 146 movable in the X-axis and Y-axis directions is disposed. The guide stage 131 is fixed to the linear way 146. The linear way 146 is fixed to the hollow shaft 160. The hollow shaft 160 is held by the bearing case 142 via the slide bush 147. The stroke of the air cylinder 136 is transmitted to the hollow shaft 160 by a compression spring 148.

  The push stage 133 is above the guide stage 131, and a push rod 149 extending downward from the center of the push stage 133 is centered by passing through the slide bush 150 at the center of the guide stage 131 and is in contact with the spline shaft 132. The push stage 133 is moved up and down by the cylinder 135 via the spline shaft 132 to load the semiconductor wafer W onto the top ring 1. A compression spring 151 for positioning is disposed at the end of the push stage 133.

  A shock killer 152 is installed for positioning in the height direction and shock absorption when the top ring guide 137 accesses the top ring 1. Each air cylinder is provided with a vertical limit sensor for checking the position of the pusher in the vertical direction. That is, sensors 153 and 154 are attached to the cylinder 135, and sensors 155 and 156 are attached to the cylinder 136, respectively. Further, in order to prevent back contamination of the semiconductor wafer from the slurry or the like adhering to the pusher, a cleaning nozzle for cleaning dirt is separately installed. A semiconductor wafer presence / absence sensor for confirming the presence / absence of a semiconductor wafer on the pusher may be separately installed. The air cylinders 135 and 136 are controlled by a double solenoid valve.

Next, the operation of the pusher 130 configured as described above will be described. FIGS. 6A to 6E are diagrams for explaining the operation of the pusher 130. FIG.
1) During loading of semiconductor wafer As shown in FIG. 6A, the semiconductor wafer W is transported above the pusher 130 by the linear transporter 105. When the top ring 1 is at the wafer load position (second transfer position) above the pusher 130 and is not holding a semiconductor wafer, the push stage 133 is raised by the air cylinder 135 as shown in FIG. . When the completion of the raising of the push stage 133 is confirmed by the sensor 153, as shown in FIG. 6C, a set of components around the guide stage 131 is raised by the air cylinder 136. On the way up, it passes the semiconductor wafer holding position of the transfer stage of the linear transporter 105. At this time, the semiconductor wafer W is centered by the taper 139a of the top ring guide 137 simultaneously with the passage, and the pattern surface (other than the edge) of the semiconductor wafer W is held by the push stage 133.

  The top ring guide 137 moves up without stopping while the push stage 133 holds the semiconductor wafer W, and the guide ring 157 is called in by the taper 138a of the top ring guide 137. The top ring 1 is centered by alignment with the linear way 146 that can move freely in the X and Y directions, and the upper stage portion 138 of the top ring guide 137 comes into contact with the lower surface of the guide ring 157, and the ascent of the guide stage 131 is completed. To do.

  The upper stage 138 of the top ring guide 137 contacts and is fixed to the lower surface of the guide ring 157, and the guide stage 131 does not rise any further. However, since the air cylinder 136 continues to rise until it hits the shock killer 152, the compression spring 148 contracts, so that only the spline shaft 132 further rises and the push stage 133 further rises. At this time, as shown in FIG. 6D, the push stage 133 holds the pattern surface (other than the edge) of the semiconductor wafer W and transports the semiconductor wafer W to the top ring 1. When the cylinder 136 rises after the semiconductor wafer W comes into contact with the top ring, the spring 151 absorbs the stroke beyond that, and the semiconductor wafer W is protected.

2) During wafer unloading The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher. When the transfer stage of the linear transporter 105 is above the pusher 130 and no semiconductor wafer is mounted, a set of components around the guide stage 131 is raised by the air cylinder 136, and the guide ring is formed by the taper 138 a of the top ring guide 137. Call 157. The top ring 1 is centered by alignment by the linear way 146, and the upper stage portion 138 of the top ring guide 137 comes into contact with the lower surface of the guide ring 157, whereby the raising of the guide stage 131 is completed.

  The air cylinder 136 continues to operate until it hits the shock killer 152, but since the upper stage 138 of the top ring guide 137 is in contact with the lower surface of the guide ring 157, the guide stage 131 is fixed to the air cylinder 136. The spline shaft 132 is pushed up together with the air cylinder 135 by overcoming the repulsive force, and the push stage 133 is raised. At this time, as shown in FIG. 6E, the push stage 133 does not reach a position higher than the semiconductor wafer holding portion of the lower stage 139 of the top ring guide 137. In this example, the cylinder 136 is set to further stroke from the point where the top ring guide 137 contacts the guide ring 157. The impact at this time is absorbed by the spring 148.

  When the raising of the air cylinder 136 is completed, the semiconductor wafer W is released from the top ring 1. At this time, the semiconductor wafer W is centered by the lower taper 139 a of the top ring guide 137, and the edge portion is held by the lower stage portion 139 of the top ring guide 137. When the semiconductor wafer W is held by the pusher, the pusher starts to descend. When descending, the guide stage 131 that has moved the center position for the centering of the top ring is centered by the guide sleeve 140 and the center sleeve 141. In the middle of the descent, the pusher passes the transfer stage of the linear transporter 105 to the transfer stage at the edge of the semiconductor wafer W, and the operation is completed when the descent ends.

  The pusher shown in FIGS. 5 and 6 can pass the polished semiconductor wafer from the top ring to the pusher without causing any impact to the semiconductor wafer by reliably detaching the semiconductor wafer from the top ring. It has a mechanism.

Next, a pusher having the above-described mechanism will be described with reference to FIGS.
7 to 9 are views showing other pushers, FIG. 7 is a schematic sectional view of the pusher, and FIG. 8 is a schematic sectional view showing a detailed structure of the suction pad. In FIG. 7, only the main part of the pusher 130 is illustrated, and a guide stage 131, a top ring guide 137, a push stage 133, a shaft 132 for moving the push stage 133 up and down, and a hollow shaft 160 are illustrated. As shown in FIG. 7, one or more suction pads 200 constituting a suction portion are provided on the upper surface of the push stage 133. As shown in FIG. 8, the suction pad 200 includes a bag-like elastic body or elastic film 201 and a suction pad main body 202 composed of upper and lower members that sandwich the open end of the bag-like elastic film 201. Yes. A substantially hemispherical or mortar-shaped recess 202 a is formed on the upper surface of the suction pad main body 202. A fluid chamber 209 is formed by the recess 202a and an elastic film (elastic body) 201 covering the recess 202a. An O-ring 203 for sealing is interposed on the mating surface of the suction pad body 202 composed of upper and lower members. The suction pad main body 202 is provided with a communication hole 204 that opens into the recess 202a on the upper surface, and the communication hole 204 is connected to a vacuum source 207 and a pressurized fluid source 208 via pipes 205 and 206. ing. A valve V11 is provided in the pipe line 205 connected to the vacuum source 207, and a valve V12 is provided in the pipe line 206 connected to the pressurized fluid source 208.

Next, the operation of the pusher 130 configured as described above will be described. 9A to 9D are diagrams for explaining the operation of the pusher.
The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher, and then the pusher is raised by the air cylinder 136 (see FIG. 5), and the upper surface of the suction pad 200 is held by the top ring 1. Contact W. At the time of this contact, the suction pad 200 is in the state shown in FIG. 8, but simultaneously with the contact, the valve V11 opens and the fluid chamber 209 of the suction pad 200 communicates with the vacuum source 207. As a result, as shown in FIG. The elastic film 201 of the suction pad 200 is dented like a suction cup, and the suction pad 200 sucks the semiconductor wafer W. Simultaneously with the suction of the semiconductor wafer by the suction pad 200, on the top ring side, pressurized fluid (for example, compressed air or nitrogen and pure water is mixed) from the communication holes 61a and 62a (see FIG. 2) to the semiconductor wafer W. The semiconductor wafer W is released by ejecting the mixed fluid). When the pressurized fluid is sprayed from the communication holes 61 a and 62 a onto the semiconductor wafer W, the pressure fluid is supplied to all the pressure chambers 22 to 25 or a part of the pressure chambers 22 to 25, and the membrane (elastic pad) 4. Alternatively, the semiconductor wafer W may be pressurized. As described above, the semiconductor wafer W is completely detached from the top ring 1 by the suction of the semiconductor wafer by the suction pad 200 or the pressurization of the membrane on the top ring side together with the injection of the pressurized fluid from the top ring side. Thereafter, as shown in FIG. 9B, the push stage 133 is lowered while the semiconductor wafer W is sucked by the suction pad 200, and the semiconductor wafer W is completely separated from the top ring 1.

  Next, the valve V11 is closed and the valve V12 is opened. As shown in FIG. 9C, a pressurized fluid such as nitrogen is introduced into the suction pad 200 from the pressurized fluid source 208, and the suction pad 200 is formed in a balloon shape. Inflate. Thereby, the semiconductor wafer W is floated from the suction pad 200, and the sticking of the suction pad 200 to the semiconductor wafer W is released. In this state, the pusher 130 is lowered, and the semiconductor wafer W is delivered from the pusher 130 to the transfer stage of the linear transporter 105 during the lowering. Then, as shown in FIG. 9D, when the pusher 130 is lowered, the semiconductor wafer W is completely delivered to the linear transporter 105.

  As described above, according to the above pusher, when the semiconductor wafer W is transferred from the top ring 1 to the pusher 130, the suction pad 200 provided on the pusher 130 sucks the semiconductor wafer W. The wafer W can be reliably peeled off. And, when the semiconductor wafer is detached from the top ring, the suction pad adsorbs the semiconductor wafer, so that a situation in which the semiconductor wafer is vigorously dropped onto the pusher by the ejection of the pressurized fluid at the time of separation is prevented. And does not impact the semiconductor wafer.

  10 and 11 are views showing still another pusher, and FIG. 10 is a schematic sectional view of the pusher. In FIG. 10, only the main part of the pusher 130 is shown, and a guide stage 131, a top ring guide 137, a push stage 133, a shaft 132 for raising and lowering the push stage 133, and a hollow shaft 160 are shown. As shown in FIG. 10, the upper surface of the push stage 133 is formed flat. A fluid supply path 210 is formed in the shaft 132 and the push stage 133 that move the push stage 133 up and down, and the fluid supply path 210 is connected to a pure water supply source 212 via a pipe 211. A valve V13 is provided in the pipeline 211 connected to the pure water supply source 212.

Next, the operation of the pusher configured as described above will be described. FIG. 11A to FIG. 11F are diagrams for explaining the operation of the pusher.
The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher, and then the pusher is raised by the air cylinder 136 (see FIG. 5), and as shown in FIG. The ring guide 137 is engaged. At this time, the valve V13 is opened, pure water is supplied from the pure water supply source 212 to the upper surface of the push stage 133 via the fluid supply path 210, and a thin water film is formed on the upper surface of the push stage 133. In this state, as shown in FIG. 11B, the push stage 133 is raised and the upper surface of the push stage 133 and the semiconductor wafer W are brought into contact with each other. At the time of this contact, the valve V13 is closed and the supply of pure water to the upper surface of the push stage 133 is stopped.

  However, since a thin water film is formed between the upper surface of the push stage 133 and the semiconductor wafer W, the semiconductor wafer W is attracted to the upper surface of the push stage 133 by the surface tension of the water film. As shown in FIG. 11C, simultaneously with the adsorption of the semiconductor wafer W through the water film by the push stage 133, on the top ring side, a pressurized fluid (for example, compression) is applied to the semiconductor wafer W from the communication holes 61a and 62a. The semiconductor wafer W is released by spraying air or a mixed fluid obtained by mixing nitrogen and pure water. When the pressurized fluid is sprayed from the communication holes 61 a and 62 a onto the semiconductor wafer W, the pressure fluid is supplied to all the pressure chambers 22 to 25 or a part of the pressure chambers 22 to 25, and the membrane (elastic pad) 4. Alternatively, the semiconductor wafer W may be pressurized. Thus, the semiconductor wafer W is completely removed from the top ring 1 by the adsorption of the semiconductor wafer W through the water film by the push stage 133 and the injection of the pressurized fluid from the top ring side and the pressurization of the membrane on the top ring side. Leave.

  Next, as shown in FIG. 11D, the push stage 133 is lowered while the semiconductor wafer W is attracted, and the semiconductor wafer W is completely separated from the top ring 1. Thereafter, the valve V13 is opened, pure water is supplied from the pure water supply source 212, pure water is caused to flow on the upper surface of the push stage 133, and the semiconductor wafer adsorption state by the water film is released. In this state, as shown in FIG. 11E, the pusher 130 is lowered, and the semiconductor wafer W is delivered from the pusher 130 to the transfer stage of the linear transporter 105 in the middle of the lowering. Then, as shown in FIG. 11 (f), when the lowering of the pusher 130 is completed, the semiconductor wafer W is completely delivered to the linear transporter 105.

  As described above, according to the pusher, when the semiconductor wafer W is transferred from the top ring 1 to the pusher 130, a thin water film is formed on the upper surface of the push stage 133, and the semiconductor wafer is adsorbed by the water film. The semiconductor wafer W can be reliably peeled off from the top ring 1. When the semiconductor wafer is detached from the top ring, the push stage adsorbs the semiconductor wafer through the water film, so that the semiconductor wafer is vigorously dropped onto the pusher by the ejection of the pressurized fluid at the time of the separation. The situation can be prevented and the semiconductor wafer W is not shocked.

  12 and 13 are views showing still another pusher, and FIG. 12 is a schematic sectional view of the pusher. In FIG. 12, only the main part of the pusher 130 is shown, and a guide stage 131, a top ring guide 137, a push stage 133, a shaft 132 for raising and lowering the push stage 133, and a hollow shaft 160 are shown. As shown in FIG. 12, the top ring guide 137 is provided with one or a plurality of nozzles 220 constituting a high-pressure fluid path, and the nozzles 220 are connected to a pressurized fluid source 222 via a pipe line 221. A valve V14 is provided in the conduit 221 connected to the pressurized fluid source 222. The pressurized fluid source 222 can supply high-pressure pure water or a high-pressure mixed fluid composed of two or more liquids and gases such as nitrogen and pure water. Further, a cover for preventing scattering of the injected high-pressure fluid is provided around the nozzle 220 (not shown).

Next, the operation of the pusher configured as described above will be described. 13A to 13C are diagrams for explaining the operation of the pusher.
The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher, and then the pusher is raised by the air cylinder 136 (see FIG. 5), and as shown in FIG. The ring guide 137 is engaged. Thereafter, as shown in FIG. 13B, on the top ring side, pressurized fluid (for example, compressed air or a mixed fluid in which nitrogen and pure water are mixed) is injected from the communication holes 61a and 62a onto the semiconductor wafer W. In addition, the pressure fluid is supplied to all the pressure chambers 22 to 25 or a part of the pressure chambers 22 to 25 to inflate the membrane (elastic pad) 4 and the pressurized fluid is supplied to the pressure chamber 21 to supply the subcarrier. By moving the plate 6 downward, the semiconductor wafer W is protruded downward from the lower end of the retainer ring 3, and the peripheral edge of the semiconductor wafer is peeled off from the membrane so as to leave a gap between the peripheral edge of the semiconductor wafer and the membrane. . With the gap between the peripheral edge of the semiconductor wafer and the membrane, the valve V14 is opened, and a high-pressure fluid (pure water or a mixed fluid of pure water or a gas such as nitrogen) is ejected from the nozzle 220, and the high-pressure fluid Then, the semiconductor wafer is peeled off from the membrane (see FIG. 13C). Next, the pusher 130 is lowered, and the semiconductor wafer W is transferred from the pusher 130 to the transfer stage of the linear transporter 105 during the lowering (not shown).

  As described above, according to the above pusher, when passing the semiconductor wafer W from the top ring 1 to the pusher 130, the pressurized fluid is supplied to all or a part of the pressure chambers 22 to 25 to expand the membrane. Then, by supplying pressurized fluid to the pressure chamber 21 and moving the subcarrier plate 6 downward, the semiconductor wafer W protrudes downward from the lower end of the retainer ring, and a gap is formed between the peripheral edge of the semiconductor wafer W and the membrane. In this state, a high-pressure fluid is sprayed between the membrane and the semiconductor wafer W from the nozzle 220. The semiconductor wafer W can be peeled off from the top ring 1 by the pressure of the high-pressure fluid. When the semiconductor wafer W is peeled off from the top ring 1, there is only a very small gap between the lower end surface of the semiconductor wafer W and the push stage 133, so that the semiconductor wafer W falls down onto the pusher 130 vigorously. There is nothing.

  14 and 15 are views showing a pusher used in the polishing apparatus according to the embodiment of the present invention. FIG. 14 is a schematic cross-sectional view of the pusher. In FIG. 14, only the main part of the pusher 130 is illustrated, and a guide stage 131, a top ring guide 137, a push stage 133, a shaft 132 that moves the push stage 133 up and down, and a hollow shaft 160 are illustrated. As shown in FIG. 14, the top ring guide 137 is provided with one or a plurality of chuck mechanisms 230 for peeling the semiconductor wafer. The chuck mechanism 230 includes a link 232 that is swingably supported by the top ring guide 137 via a pin 231, and an air cylinder 233 connected to the lower end of the link 232. The tip 232a of the link 232 is tapered so that it can easily enter between the membrane (elastic pad) 4 on the top ring side and the semiconductor wafer W.

Next, the operation of the pusher configured as described above will be described. FIG. 15A and FIG. 15B are diagrams for explaining the operation of the pusher.
The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher, and then the pusher is raised by the air cylinder 136 (see FIG. 5), and as shown in FIG. The part enters the top ring guide 137. Thereafter, on the top ring side, pressurized fluid (for example, compressed air or a mixed fluid in which nitrogen and pure water are mixed) is sprayed to the semiconductor wafer W from the communication holes 61a and 62a, and all the pressure chambers 22 to 25 are injected. Alternatively, by supplying pressure fluid to a part of the pressure chambers 22 to 25 to expand the membrane (elastic pad) 4 and supplying pressurized fluid to the pressure chamber 21 to move the subcarrier plate 6 downward, The semiconductor wafer W is protruded downward from the lower end of the retainer ring 3, and the peripheral edge of the semiconductor wafer is peeled off from the membrane so as to leave a gap between the peripheral edge of the semiconductor wafer and the membrane. In this state, as shown in FIG. 15B, the air cylinder 233 is operated to swing the link 232, and the tip 232a of the link 232 is inserted between the membrane on the top ring side and the semiconductor wafer W. Later, the link 232 is swung, and the semiconductor wafer W is forcibly separated from the membrane by the link 232. Thereafter, the push stage 133 is lowered, and the semiconductor wafer W is completely separated from the top ring 1. Next, the pusher 130 is lowered, and the semiconductor wafer W is transferred from the pusher 130 to the transfer stage of the linear transporter 105 during the lowering (not shown).

  As described above, according to the pusher of the present embodiment, when the semiconductor wafer is transferred from the top ring to the pusher, the pressurized fluid is supplied to all or a part of the pressure chambers 22 to 25 to inflate the membrane. Then, by supplying pressurized fluid to the pressure chamber 21 and moving the subcarrier plate 6 downward, the semiconductor wafer W protrudes downward from the lower end of the retainer ring, and a gap is formed between the peripheral edge of the semiconductor wafer W and the membrane. In this state, the air cylinder 233 is operated so that the tip 232a of the link 232 enters between the membrane on the top ring side and the semiconductor wafer W, and the semiconductor wafer W is forcibly peeled off from the top ring 1. be able to. When the semiconductor wafer W is peeled off from the top ring 1, there is only a very small gap between the lower end surface of the semiconductor wafer W and the push stage 133, so that the semiconductor wafer W falls down onto the pusher 130 vigorously. There is nothing.

  FIG. 16 is a schematic cross-sectional view showing still another pusher. The chuck mechanism 240 for peeling off the semiconductor wafer in this example includes a link 242 supported by the top ring guide 137 via a pin 241 so as to be movable in the radial direction, and an air cylinder 243 connected to the lower end of the link 242. It is configured. The front end 242a of the link 242 has a concave shape so that the end face of the semiconductor wafer W can be gripped.

Next, the operation of the pusher configured as described above will be described. FIGS. 17A to 17C are diagrams for explaining the operation of the pusher.
The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher, and then the pusher is raised by the air cylinder 136 (see FIG. 5). As shown in FIG. The part enters the top ring guide 137. Thereafter, on the top ring side, pressurized fluid (for example, compressed air or a mixed fluid in which nitrogen and pure water are mixed) is sprayed to the semiconductor wafer W from the communication holes 61a and 62a, and all the pressure chambers 22 to 25 are injected. Alternatively, by supplying pressure fluid to a part of the pressure chambers 22 to 25 to expand the membrane (elastic pad) 4 and supplying pressurized fluid to the pressure chamber 21 to move the subcarrier plate 6 downward, The semiconductor wafer W is protruded downward from the lower end of the retainer ring 3, and the peripheral edge of the semiconductor wafer is peeled off from the membrane so as to leave a gap between the peripheral edge of the semiconductor wafer and the membrane. In this state, as shown in FIG. 17B, the air cylinder 243 is operated to move the link 242 inward in the radial direction, and the end of the semiconductor wafer W is moved from the left and right by the recess of the tip 242a of the link 242. Hold it. Thereafter, as shown in FIG. 17C, the pusher 130 is lowered, and the semiconductor wafer W is completely separated from the top ring 1 while being held by the link 242. Next, the pusher 130 is lowered, and the semiconductor wafer W is transferred from the pusher 130 to the transfer stage of the linear transporter 105 during the lowering (not shown).

  As described above, according to the above pusher, when passing a semiconductor wafer from the top ring to the pusher, the pressurized fluid is supplied to all or part of the pressure chambers 22 to 25 to inflate the membrane, and the pressure chamber By supplying a pressurized fluid to 21 and moving the subcarrier plate downward, the semiconductor wafer W protrudes downward from the lower end of the retainer ring, and a gap is formed between the peripheral edge of the semiconductor wafer W and the membrane, In this state, the air cylinder 243 is operated so that the tip 242a of the link 242 enters between the membrane on the top ring side and the semiconductor wafer W, and the semiconductor wafer W can be forcibly peeled off from the top ring. When the semiconductor wafer W is peeled off from the top ring 1, there is only a very small gap between the lower end surface of the semiconductor wafer W and the push stage 133, so that the semiconductor wafer W falls down onto the pusher 130 vigorously. There is nothing.

  18 and 19 are views showing still another pusher, and FIG. 18 is a schematic sectional view of the pusher. In FIG. 18, only the main part of the pusher 130 is illustrated, and a guide stage 131, a top ring guide 137, a push stage 133, a shaft 132 that moves the push stage 133 up and down, and a hollow shaft 160 are illustrated. As shown in FIG. 18, a flange 250 is provided on the radially outer side of the pusher 130. The cylindrical container-shaped scissors 250 are installed concentrically with the shaft 132 of the pusher 130, the cylindrical portion 250a of the scissors 250 is formed larger than the outer diameter of the pusher 130, and an opening 250c is formed in the bottom 250b of the scissors 250. Is provided. The tub 250 is connected to a pure water source 252 through a pipe 251, and a valve V <b> 16 is provided in the pipe 251. In addition, a drain pipe 253 is provided at the bottom 250b of the rod 250, and a valve V17 is provided in the drain pipe 253. An air cylinder 254 is connected to the bottom 250b of the rod 250, and the rod 250 can be moved up and down by the air cylinder 254.

Next, the operation of the pusher configured as described above will be described. FIGS. 19A and 19B are diagrams for explaining the operation of the pusher.
The semiconductor wafer W is transferred by the top ring 1 to the wafer unloading position above the pusher, and then the pusher is raised by the air cylinder 136 (see FIG. 5), and as shown in FIG. The ring guide 137 is engaged. In this state, the air cylinder 254 is actuated to raise the rod 250, and the pusher 130 and the lower part of the top ring 1 are accommodated in the rod 250. In this state, the O-ring 255 provided in the opening 250c of the flange 250 engages with the cylindrical member 260 protruding downward from the pusher 130 and is in a sealed state. In this state, as shown in FIG. 19B, the valve V16 is opened, pure water is supplied from the pure water source 252 into the tub 250, and the entire pusher 130 and the lower side of the top ring 1 are immersed in water. To.

  At this time, on the top ring side, pressurized fluid (for example, compressed air or a mixed fluid in which nitrogen and pure water are mixed) is injected from the communication holes 61a and 62a onto the semiconductor wafer W, and all the pressure chambers 22 to 25, or a pressure fluid is supplied to a part of the pressure chambers 22 to 25 to inflate the membrane (elastic pad) 4, and a pressurized fluid is supplied to the pressure chamber 21 to move the subcarrier plate 6 downward. The semiconductor wafer W is protruded downward from the lower end of the retainer ring 3, and the peripheral edge of the semiconductor wafer is peeled off from the membrane so as to leave a gap between the peripheral edge of the semiconductor wafer and the membrane. Thereby, pure water enters between the membrane (elastic pad) 4 on the top ring side and the semiconductor wafer W, the close contact state between the top ring 1 and the semiconductor wafer W is released, and the semiconductor wafer W is detached from the top ring 1. . Thereafter, the push stage 133 is lowered, and the semiconductor wafer W is completely separated from the top ring 1. Next, the pusher 130 is lowered, and the semiconductor wafer W is transferred from the pusher 130 to the transfer stage of the linear transporter 105 during the lowering (not shown).

  In this example, when the semiconductor wafer W is delivered from the top ring 1 to the pusher 130, the semiconductor wafer W is immersed in pure water. ) And the like are removed, and the semiconductor wafer is simultaneously cleaned. Thereafter, by opening the valve V17 of the drain pipe 253, pure water is discharged from the inside of the bottle 250, and after discharging the pure water, the air cylinder 254 is operated to lower the bottle 250, and the semiconductor wafer delivery operation is completed. .

  As described above, according to the above-described pusher, the pure water stored in the basket causes water to enter between the semiconductor wafer held on the top ring and the semiconductor wafer holding surface of the top ring, and the top ring and the semiconductor wafer are in contact with each other. The contact state can be released, and the semiconductor wafer W can be peeled off from the top ring 1. When the semiconductor wafer W is detached from the top ring 1, water is interposed between the push stage 133 and the semiconductor wafer W, so that when the semiconductor wafer W is detached, the water drops vigorously on the pusher by the ejection of the pressurized fluid. It is possible to prevent such a situation.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Top ring 2 Top ring main body 2a Housing part 2b Pressure sheet support part 2c Seal part 2d Spherical recessed part 3 Retainer ring 3a Through-hole 4 Elastic pad 5 Holder ring 5a Upper end part 5b Stopper part 5c Protrusion 6 Subcarrier plate 7 Pressurization Seat 8 Center bag 9 Ring tube 10 Universal joint part 11 Top ring drive shaft 11a Spherical concave part 12 Bearing ball 21, 22, 23, 24, 25 Pressure chamber 26 Space 31, 32, 33, 34, 35, 36, 37, 38 Fluid path 39 Relief port 41 Opening 51 Cleaning liquid path 52 Through hole 53, 61a, 61b, 62a, 62b, 204 Communication hole 55, 56 Screw 61, 62 Adsorption part 61b, 62b Elastic sheet 62 Outer peripheral part adsorption part 81, 91 201 Elastic membrane 82 Center bar Holder 82a, 92a screw hole 92 ring tube holder 100 polishing table 101 polishing pad 102 polishing liquid supply nozzle 105 linear transporter 110 top ring shaft 110 top ring head 111 top ring air cylinder 112 rotating cylinder 113, 116 timing pulley 114 top ring Motor 115 timing belt 117 top ring head shaft 120 compressed air source 121, 207 vacuum source 130 pusher 131 guide stage 132 spline shaft 133 push stage 134 floating joint 135, 136, 233, 243, 254 air cylinder 137 top ring guide 138 upper stage 138a, 139a Taper 139 Lower step 140 Guide sleeve 141 Centers Tube 142 Bearing case 143 Motor housing 144 V ring 145 Hole 146 Linear way 147 Slide bush 149 Push rod 150 Slide bush 152 Shock absorber 153, 154, 155, 156 Sensor 157 Guide ring 160 Hollow shaft 200 Suction pad 202 Suction pad main body 202a Recess 203, 255 O-ring 205, 206, 211, 221, 224 Pipe 208, 222 Pressurized fluid source 209 Fluid chamber 210 Fluid supply path 212 Pure water supply source 220 Nozzle 230, 240 Chuck mechanism 231, 241 Pins 232, 242 Link 232a, 242a Tip 250 桶 250a Cylindrical part 250b Bottom part 250c Opening 252 Pure water source 253 Drain pipe 260 Cylindrical member G Gap Q Polishing liquid R1, R2, R , R4, R5, R6 regulator TS1, TS2 transport stage V1, V2, V11, V12, V13, V14, V16, V17 valve W semiconductor wafer

Claims (5)

A polishing apparatus comprising: a substrate holding unit that holds a substrate; a substrate mounting unit that mounts a substrate; and a substrate transfer unit that includes a lifting unit that lifts and lowers the substrate mounting unit.
The substrate transfer unit, with the oscillation of the swingably supported links via a pin, said the gap formed between the periphery of the substrate held by the substrate holder and the substrate holder intruded the tapered tip of the links, pulling from the front Stories substrate holding portion distal Hosojo tip the substrate was further oscillating the link while in contact with the periphery of the substrate is moved in a direction away from the substrate holding portion A polishing apparatus having a chuck mechanism for peeling.   The substrate holding unit supplies pressurized fluid to the substrate from a contact surface of the substrate holding unit that contacts the substrate when the substrate is transferred from the substrate holding unit to the substrate mounting unit. The polishing apparatus according to claim 1, wherein the polishing apparatus is characterized. The substrate holding portion includes a substrate holding portion main body that holds the substrate, an elastic pad that has a contact surface that contacts the substrate, and a support member that supports the elastic pad,
The elastic pad has an opening;
The polishing apparatus according to claim 1, further comprising a supply source that supplies a fluid or a vacuum to the opening. Attaching a contact member having an elastic film that contacts the elastic pad on the lower surface of the support member,
In a space formed between the elastic pad and the support member, a first pressure chamber formed inside the contact member and a second pressure chamber formed outside the corresponding contact member are formed. And
Having a third pressure chamber in a space formed between the substrate holding body and the support member;
The supply source includes a first pressure chamber formed inside the abutting member, a second pressure chamber formed outside the abutting member, and a fluid or vacuum in the third pressure chamber, respectively. The polishing apparatus according to claim 3, wherein the polishing apparatus can be supplied independently. Polish the substrate held while contacting the elastic pad of the substrate holding part,
After polishing, the elastic pad is expanded to form a gap between the peripheral edge of the substrate held by the substrate holding part and the elastic pad,
The link swingably supported via the pin to the substrate transfer unit is swung intruded the tapered tip of the link to the gap, the link while abutting the tip Hosojo tip peripheral portion of the substrate polishing method characterized by separating from the elastic pad by further moving the substrate is swung in a direction away from said resilient pad.

Images