JP2000061824A - Carrier and polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier and a polishing device which can control each of forces applied to a retainer ring, applied to the outer peripheral part of a workpiece, and to the center part of the latter, so as to uniformly polish the entire surface of the workpiece and to automatically regulate the degree of projection of the workpiece. SOLUTION: A carrier 1 is composed of a carrier body 2, a retainer ring 3 projected from the outer periphery of the lower surface of the carrier body 2, a movable element 4 fitted in the carrier boy 2 so as to be vertically movable, and a rotation transmitting mechanism for rotating the movable element 4 together with the carrier body 2. A pressure chamber 5 is formed above the movable element 4, and an wafer outer periphery pressing part 40 for pressing the outer peripheral part Wa of a wafer W with a pressure corresponding to a pneumatic pressure in the pressure chamber 5, is formed in a presser 44 in the movable element 4. Further, a pressure chamber 41 for pressing the center part of the wafer W through the intermediary of a flexible sheet 45 is defined in the presser 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier and a polishing device for uniformly polishing the surface of a workpiece by uniformly pressing the back surface of the workpiece with a fluid such as air.

[0002]

2. Description of the Related Art FIG. 12 is a sectional view showing an example of a conventional pneumatic carrier. A space 201 is formed on the lower surface of the carrier 200.
Is covered with a sheet 202 to define a pressure chamber R. An air supply passage 203 communicating with the pressure chamber R is provided in the center of the carrier 200, and a retainer ring 204 for holding the wafer W is attached to the outer peripheral portion of the lower surface of the sheet 202. With this configuration, the wafer W
Can be stored inside the retainer ring 204, and the carrier 200 can be rotated while the wafer W is in contact with the polishing pad 101 of the rotating lower platen 100. At this time, by supplying air into the pressure chamber R from the air supply path 203, the back surface of the wafer W is uniformly pressed by the air, and the front surface of the wafer W is flatly polished by the lower surface plate 100.

[0003]

However, the above-mentioned conventional techniques have the following problems. Carrier 2
In 00, as shown in FIG. 13, since the outer peripheral portion of the sheet 202 is pulled downward during the polishing operation of the wafer W,
A vertical component T1 of the tension T is applied to the outer peripheral portion of the wafer W in addition to the pressure of air. Therefore, the polishing rate of the outer peripheral portion of the wafer W becomes higher than the polishing rates of the other portions. As a result, overpolishing of the outer peripheral portion of the wafer W occurs,
Yield deteriorates. By the way, the polishing rate of the outer peripheral portion of the wafer W is determined by the protrusion amount Δ of the wafer W from the retainer ring 204. Therefore, it is necessary to previously adjust the protrusion amount Δ for achieving the desired polishing rate. However, if the polishing operation is performed for a certain period of time, the retainer ring 204 in contact with the polishing pad 101 is worn, and the protrusion amount Δ greatly differs from the initial amount. For this reason,
The polishing device is stopped each time, and the retainer ring 204
Had to be replaced, leading to a decrease in equipment availability.

The present invention has been made to solve the above-mentioned problems, and it is possible to control the force applied to the retainer ring, the force applied to the outer peripheral portion of the workpiece, and the force applied to the central portion of the workpiece. And then
It is an object of the present invention to provide a carrier and a polishing device that enable uniform polishing of the entire surface of a workpiece and automatic adjustment of the protrusion amount of the workpiece.

[0005]

In order to solve the above-mentioned problems, the invention of claim 1 is a retainer ring projecting from the outer periphery of the lower surface of a carrier body and capable of surrounding and holding a workpiece, and a retainer ring. A carrier provided with a movable body, which is vertically movable inside and is capable of contacting substantially the entire upper surface of a work piece, and a rotation transmission mechanism for rotating the movable body integrally with a carrier body. , A gap between the upper surface of the movable body and the lower surface of the carrier body is used to form an airtight first pressure chamber, and a workpiece outer peripheral pressing portion capable of pressing the outer peripheral surface of the upper surface of the workpiece is provided on the lower surface portion of the movable body. A second pressure chamber is formed by projectingly and airtightly covering a space formed inside the workpiece outer peripheral pressing portion from below with a flexible sheet. With such a configuration, when the retainer ring protruding from the outer periphery of the lower surface of the carrier body surrounds and holds the workpiece on the lower surface plate from the outside, the lower surface portion of the movable body that is vertically movable inside the retainer ring is Contact almost the entire top surface of the workpiece. When the carrier body is rotated in this state, the movable body rotates integrally with the carrier body due to the action of the rotation transmission mechanism. Almost at the same time, when the carrier body is pressed down with a predetermined force, if the retainer ring is in contact with the lower surface plate, the retainer ring is pressed with a pressure corresponding to the pressing force. Further, when a fluid having a predetermined pressure is supplied into the airtight first pressure chamber formed by using the gap between the upper surface of the movable body and the lower surface of the carrier body,
The fluid pressure in the pressure chamber is transmitted to the workpiece outer peripheral pressing portion of the movable body, and the upper surface outer peripheral portion of the workpiece is pressed at a pressure corresponding to the fluid pressure in the first pressure chamber. Further, when the fluid having a predetermined pressure is supplied into the second pressure chamber, the portion of the workpiece other than the outer peripheral portion of the upper surface is pressed by the pressure corresponding to the fluid pressure in the second pressure chamber.

Further, as a preferable example of the rotation transmission mechanism, the invention of claim 2 is the carrier according to claim 1, wherein the rotation transmission mechanism is provided in a central portion of the carrier body and has a hole opened to the movable body side. The movable body is provided with a flange protruding from the center of the upper surface and fitted in a hole.
The hole is made up of a plurality of protrusions projectingly provided on the circumferential surface, and the hole has a plurality of vertical groove portions to which the plurality of flange protrusions are vertically movably engaged, and the plurality of vertical groove portions. It is configured to have a stopper portion which is located at the lowest position and receives the protrusion portion of the flange. With this configuration, when the carrier body is rotated, the flange fitted in the hole is rotated by the engagement between the vertical groove portion in the hole of the carrier body and the protrusion of the flange, and the movable body is rotated integrally with the carrier body. To do. Further, when the movable body is pressed downward by the fluid pressure in the first pressure chamber, the protrusion of the flange moves downward in the vertical groove together with the movable body. When the protrusion reaches the bottom of the vertical groove, the protrusion is received by the stopper, and further downward movement of the movable body is prevented. Also, when the lower surface of the retainer ring is worn, the retainer ring is kept in contact with the lower surface plate due to the pressing force applied to the carrier body, and the movable body is affected by the pressing force applied to the carrier body. The amount of protrusion of the workpiece from the retainer ring is maintained at the initial amount of protrusion because the amount of wear of the retainer ring relatively increases without being received.

By the way, a polishing apparatus using the carrier according to the above-mentioned claim 1 and claim 2 is also realized as a product invention.
Therefore, the invention of claim 3 is such that a rotatable lower platen and a retainer ring projectingly provided on the outer periphery of the lower surface of the carrier body and capable of surrounding and holding a work piece on the lower platen from the outside, and a retainer ring inside the retainer ring A movable body that is movably mounted and whose lower surface can contact almost the entire upper surface of the workpiece, and a carrier that has a rotation transmission mechanism that rotates this movable body integrally with the carrier body, and rotates while pressing the carrier. And a rotary drive means for rotating the workpiece, wherein an airtight first pressure chamber is formed by using a gap between an upper surface of a movable body of a carrier and a lower surface of the carrier body, and a peripheral portion of an upper surface of a workpiece. A workpiece outer peripheral pressing portion that can press is projected on the lower surface of the movable body, and the space formed inside the workpiece outer peripheral pressing portion is airtight from the lower side with a flexible sheet. And a second fluid supply means capable of supplying a fluid to the first pressure chamber of the carrier, and a second fluid supply means capable of supplying a fluid to the second pressure chamber. Is provided. Further, the invention of claim 4 is the polishing apparatus according to claim 3, wherein the rotation transmission mechanism of the carrier is provided in a central portion of the carrier main body, and a hole opened to the movable body side and a central portion of the upper surface of the movable body. The flange of the rotation transmission mechanism has a plurality of protrusions provided on its peripheral surface, and the hole of the rotation transmission mechanism has a flange A plurality of vertical groove portions in which a plurality of protrusion portions are vertically movably engaged, and a stopper portion located at the lowest position of the plurality of vertical groove portions for receiving the protrusion portion of the flange are adopted. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway front view showing a polishing apparatus according to an embodiment of the present invention. The polishing apparatus shown in FIG. 1 is a CMP apparatus, and includes a lower surface plate 100 having a polishing pad 101 attached to its surface, a carrier 1, a rotary drive mechanism 8 as a rotary drive unit, and first and second fluid supply units. Air pump 9-1,
9-2 and.

The lower surface plate 100 is driven to rotate by a main motor 112 inside the apparatus casing.
That is, the belt 118 includes the pulley 114 attached to the main motor 112 and the input rotary shaft 1 of the transmission 115.
It is wound around the pulley 117 attached to 19,
The lower turn table 100 is attached to the output rotary shaft 119 of the transmission 115. As a result, the rotation of the main motor 112 is transmitted to the pulley 117, the rotation of the pulley 117 is changed by the transmission 115, and is transmitted to the output rotation shaft 119.
The lower surface plate 100 rotates at a predetermined speed.

The rotary drive mechanism 8 is a mechanism for rotating the carrier 1 while pressing it, and includes a cylinder 80 and a motor 84. FIG. 2 is a sectional view showing the rotary drive mechanism 8. As shown in FIG. 2, the cylinder 80 includes a piston rod 82 penetrating the cylinder body 81 and the cylinder body 8 fixed to the outside of the piston rod 82.
1 and a piston 83 fitted in an airtight manner. Accordingly, by adjusting the air pressure in the cylinder body 81, the piston rod 82 can be moved up and down integrally with the piston 83, and the pressing force on the carrier 1 can be adjusted. On the other hand, the motor 84 is attached to the piston rod 82 of the cylinder 80. That is, the gear 85 of the rotating shaft of the motor 84 is meshed with the gear 87 attached to the upper portion of the piston rod 82 via the bearing 86. Then, the upper end of a cylindrical inner rod 89 is fixed to a supporting member 88 fixed to the upper surface of the gear 87. As a result, when the motor 84 is driven, its rotation is transmitted to the inner rod 89 via the gears 85 and 87 and the support member 88, and the inner rod 89 rotates within the piston rod 82 at a predetermined speed.

The carrier 1 has a structure capable of rotating while holding the wafer W on the polishing pad 101 (see FIG. 1) of the lower surface plate 100, and is attached to the lower end of the piston rod 82. There is. FIG. 3 is a sectional view showing the structure of the carrier 1, and FIG. 4 is an exploded perspective view thereof. As shown in FIGS. 3 and 4, the carrier 1 is
Carrier body 2, retainer ring 3 assembled to carrier body 2, movable body 4 mounted inside retainer ring 3 so as to be vertically movable, and pressure chamber 5 for movable body 4.
It is provided with a (first pressure chamber) and a rotation transmission mechanism 6 for rotating the movable body 4 integrally with the carrier body 2.

The carrier body 2 is composed of a housing 10 and a carrier base 11. Specifically, as shown in FIG. 3, the housing 10 has a rotatable connecting member 10a at the center, and the lower end of the piston rod 82 is connected to the connecting member 10a. The housing 10 has an internal gear 10b on the lower side of the connecting member 10a.
The internal gear 10b has a connecting member 10a.
Is meshed with an external gear 89a formed at the lower end of the inner rod 89 that penetrates through the center hole. The carrier base 11 is provided with a screw 2a on the lower surface of the housing 10.
It is fixed at. As a result, when the inner rod 89 is rotated by the drive of the motor 84 (see FIGS. 1 and 2),
Due to the meshing of the internal gear 10b and the external gear 89a, the rotational force of the motor 84 is applied to the housing 10, and the entire carrier body 2 rotates.

The retainer ring 3 is a member for enclosing and holding the wafer W from the outside, and is provided so as to project on the outer periphery of the lower surface of the carrier body 2. Specifically, a notch 11c having the same width as the retainer ring 3 is formed on the lower surface of the outer periphery of the carrier base 11, and the screw 2 is inserted in the notch 11c while the upper portion of the retainer ring 3 is fitted.
It is fixed at b. Thus, by pressing the carrier 1 with the cylinder 80, the pressing force can be transmitted to the retainer ring 3.

The movable body 4 has a wafer outer peripheral pressing portion 40 (workpiece outer peripheral pressing portion) and a pressure chamber 41 (second pressure chamber). Specifically, the movable body 4 is composed of an upper board 43 and a pressing board 44 fixed to the lower surface of the upper board 43, and the pressure receiving portion 4 provided in the central portion of the upper surface of the upper board 43 in a protruding manner.
2 is fitted in a recess 50 formed in the center of the lower surface of the carrier base 11. On the other hand, the pressing plate 44 is formed to have a size capable of contacting the entire upper surface of the wafer W,
The wafer outer peripheral pressing portion 40 and the pressure chamber 41 are formed on the pressing plate 44. The wafer outer peripheral pressing portion 40 is formed by forming a concave portion 41a (space portion) so as to leave a portion of the lower surface portion of the pressing plate 44 capable of pressing the upper peripheral portion Wa of the wafer W. That is, the wafer outer peripheral pressing portion 40 forms the outer peripheral portion of the pressing plate 44, and the thickness thereof is equal to the outer peripheral portion Wa of the wafer W. The pressure chamber 41 is defined by airtightly covering a recess 41 a formed inside the wafer outer peripheral pressing portion 40 from below with a two-layer flexible sheet 45. The flexible sheet 45 has a plurality of holes 45a for adsorbing the wafer W. This allows
By supplying air of a predetermined pressure into the pressure chamber 41, the upper surface portion (center portion) of the wafer W except the outer peripheral portion Wa is uniformly pressed by the air pressure in the pressure chamber 41 via the flexible sheet 45. You can

The pressure chamber 5 is a space portion for applying a pressing force to the movable body 4, and the upper surface 42a of the pressure receiving portion 42 of the movable body 4 (see FIG. 4) and the recess 50 of the carrier base 11.
Of the lower surface 50a (see FIG. 4). Then, the seal member 51 is provided between the outer peripheral surface of the pressure receiving portion 42 and the inner peripheral surface of the recess 50, and the seal member 52 includes the shaft 6 described later.
The airtightness of the pressure chamber 5 is maintained by being interposed between the outer peripheral surface of 0 and the inner peripheral surface of the hole 62. As a result, the pressure chamber 5
By supplying air of a predetermined pressure into the inside of the movable body 4 and pressing the pressure receiving portion 42 of the movable body 4 with the air pressure in the pressure chamber 5, the wafer outer peripheral pressing portion 40 presses the outer peripheral portion Wa of the wafer W into the pressure receiving portion 42. It is possible to press with a pressing force corresponding to the pressing force received by.

FIG. 5 is a partially enlarged view showing the structure of the rotation transmission mechanism 6, FIG. 6 is a perspective view showing the flange 61, and FIG. 7 is a perspective view showing the structure of the hole 62 partially broken away. is there. As shown in FIG. 5, the rotation transmission mechanism 6 has a shaft 60 protruding from the center of the upper surface 42a of the pressure receiving portion 42 of the movable body 4.
A flange 61 attached to the upper end of the carrier base 11, and a hole 62 formed in the center of the upper side of the recess 50 of the carrier base 11 so as to communicate with the recess 50.

The flange 61 is a member for fitting in the hole 62, and its outer diameter is set to be substantially equal to the inner diameter of the hole 62. In addition, as shown in FIG.
The outer peripheral surface 61b is provided with four protrusions 61a protruding in the radial direction from the outer peripheral surface 61b. On the other hand, hole 6
As shown in FIG. 7, the No. 2 has four vertical groove portions 62a on its inner peripheral surface 62b with which four protrusion portions 61a of the flange 61 can be engaged. The lengths of the vertical groove portions 62a are set to be longer than the height of the protrusion portions 61a, and as shown in FIG. 5, the protrusion portions 6 engaged with the vertical groove portions 62a.
1a slides up and down in the vertical groove 62a. Such a vertical groove portion 62 a is open above the hole 62, but is closed below the hole 62.
That is, the bottom surface of the vertical groove portion 62a forms the stopper portion 62c that receives the protrusion 61a. Accordingly, when the movable body 4 moves up and down according to the magnitude of the air pressure in the pressure chamber 5, the flange 61 moves up and down in the hole 62. When the protrusion 61a of the flange 61 contacts the stopper 62c of the vertical groove 62a, the lowering operation of the movable body 4 is blocked, and the upper surface 42a of the pressure receiving portion 42 contacts the lower surface 50a of the recess 50. When this happens, the upward movement of the movable body 4 is blocked. Also, the vertical groove portion 62a of the hole 62 and the flange 6
When the carrier body 2 rotates, this rotational force is transmitted to the movable body 4 so that the movable body 4 rotates integrally with the carrier body 2.

The air pump 9-1 shown in FIG. 1 is a device for supplying air of a desired pressure to the pressure chamber 5 by using an air hose 90-1. The air hose 90-1 extended from the air pump 9-1 is inserted into the inner rod 89. Then, as shown in FIG. 3, the tip end thereof is drawn into the ventilation hole 91-1 formed in the carrier base 11, and the sealing member 9 mounted in the ventilation hole 91-1 is installed.
It is held by 2-1. The vent hole 91-1 into which the air hose 90-1 is drawn is connected to the pressure chamber 5 so that the air from the air pump 9-1 is supplied to the pressure chamber 5 through the air hose 90-1. Has become. Thereby, the air pressure in the pressure chamber 5 can be freely controlled by adjusting the air pressure by the air pump 9-1. On the other hand, the air pump 9 shown in FIG.
Reference numeral -2 is a device for supplying air of a desired pressure to the pressure chamber 41 of the movable body 4 by using the air hose 90-2.
Air hose 90-2 extended from the air pump 9-2
Are inserted into the inner rod 89 together with the air pump 9-1. Here, the air passage formed in the movable body 4 for guiding the air from the air hose 90-2 to the pressure chamber 41 will be described. FIG. 8 shows the pressure chamber 4 of the movable body 4.
FIG. 3 is an exploded perspective view of a movable body 4 for clearly showing an air passage to 1. As shown in FIGS. 3, 5 and 8, the flange 6
One vent hole 91-2 is provided which opens at the center of the upper surface of 1 and opens at the center of the lower surface of the upper plate 43. Also,
As shown in FIG. 8, ventilation holes 91-2 are formed on the lower surface of the upper board 43.
A plurality of grooves 92-2 communicating with the above are radially formed. A plurality of vent holes 93-2 communicating with the plurality of grooves 92-2 and the pressure chamber 41 are formed in the pressing plate 44. As described above, the tip end portion of the air hose 90-2 inserted into the inner rod 89 together with the air hose 90-1 is
As shown in FIG. 3, the seal member 94-2 is drawn into the vent hole 91-2 and mounted in the vent hole 91-2.
Is held by. Thereby, the vent hole 91-2
The air from the air hose 90-2 inside the plurality of grooves 92-
It flows through the ventilation hole 93-2 through 2 and is supplied to the pressure chamber 41. Therefore, the air pressure in the pressure chamber 41 can be freely controlled by adjusting the air pressure with the air pump 9-2.

Next, the operation of the polishing apparatus of this embodiment will be described. FIG. 9 is a schematic cross-sectional view showing the pressure applied to the retainer ring 3, the wafer outer peripheral pressing portion 40 and the flexible sheet 45 of the carrier 1. At the time of polishing the wafer W, as shown in FIG. 9, the retainer ring 3 of the carrier 1 and the flexible sheet 45 of the movable body 4 are brought into contact with the back surface of the wafer W, and the main motor 112 shown in FIG. Is driven to rotate the lower surface plate 100 at a predetermined speed. In parallel with this operation, while the carrier 1 holding the wafer W is pressed onto the polishing pad 101 of the lower surface plate 100 by the cylinder 80 of the rotary drive mechanism 8, the carrier 1 is rotated by the motor 84. Then, the movable body 4 rotates integrally with the carrier body 2 by the engaging action of the flange 61 of the rotation transmission mechanism 6 and the hole 62. In this state, when air having a predetermined pressure is supplied from the air pump 9-1 into the pressure chamber 5, the air pressure in the pressure chamber 5 is transmitted to the wafer outer peripheral pressing portion 40 of the movable body 4, and the air having the predetermined pressure is supplied to the air pump. 9
When supplied from -2 into the pressure chamber 41 of the movable body 4, the air pressure in the pressure chamber 41 presses the flexible sheet 45 downward.
Here, the force balance in each part will be specifically described. The downward force Fd applied to the carrier 1 by the cylinder 80, the pressure applied to the retainer ring 3 is Pr, the air pressure in the pressure chamber 5 is P5, the pressure applied to the wafer outer peripheral pressing portion 40 is Pe, and the air pressure in the pressure chamber 41 is P4, The contact area between the retainer ring 3 and the polishing pad 101 is Sr, the area of the upper surface 42a of the pressure receiving portion 42 is S5, the area of the lower surface of the wafer outer peripheral pressing portion 40 is Se, and the area of the flexible sheet 45 inside the pressure chamber 41. Is S4. Then, since the downward force Fd is divided into a component force on the retainer ring 3 and a component force on the pressure chamber 5, the following formula (1) is established. Fd = Pr.Sr + P5.S5 (1) Further, the component force to the pressure chamber 5 is pressed against the upper surface of the wafer W by the flexible sheet 45 which tends to expand due to the pressure in the pressure chamber 41. Therefore, the following equation (2) is established. P5 * S5 = P4 * S4 + Pe * Se ... (2) When the above expressions (1) and (2) are modified, the following expressions (3) and (4) are obtained. Pr = (Fd-P5.S5) / Sr ... (3) Pe = (P5.S5-P4.S4) / Se .. (4) Therefore, the pressure applied to the wafer outer peripheral pressing portion 40 of the movable body 4. When Pe is larger than the pressure P4 applied to the flexible sheet 45, the pressure of the air supplied from the air pump 9-1 to the pressure chamber 5 is reduced, that is, as shown in the above formula (4). Moreover, by reducing the air pressure P5 in the pressure chamber 5, the pressure Pe can be made equal to the air pressure P4, and as a result, the polishing rate of the entire surface of the wafer W can be made uniform. When the pressure Pe applied to the wafer outer peripheral pressing portion 40 is smaller than the pressure P4 applied to the flexible sheet 45, the air pressure P5 in the pressure chamber 5 is increased to make the pressure Pe equal to the air pressure P4. You can

By the way, when a flexible sheet 45 having a two-layer structure consisting of a hard surface layer and a soft back layer (for example, IC1000 / SUBA400 manufactured by Rodel Co.) is used, the pressing force Pe of the wafer outer peripheral pressing portion 40 is changed to the pressure chamber 41. Inner air pressure P4
However, the edge portion We in the outer peripheral portion Wa of the wafer W may be excessively polished or insufficiently polished. In such a case, the edge portion We is adjusted by adjusting the pressing force Pr of the retainer ring 3.
It is possible to prevent excessive polishing or insufficient polishing. That is, since the above expression (3) is established, the edge portion We is increased by increasing or decreasing the downward force Fd to the carrier 1 while keeping the forces P5 and S5 in the pressure chamber 5 constant. Polishing rate can be increased or decreased.

When the wafer W is polished for a long time as described above, the lower surface 3a of the retainer ring 3 which is in contact with the polishing pad 101 in a pressed state is worn. FIG. 10 is a schematic cross-sectional view showing the automatic adjusting action of the protrusion amount of the wafer W. As shown in FIG. 9, when the amount of protrusion of the wafer W from the retainer ring 3 was set to a desired value Δ in the initial state, the polishing operation was performed for a long time, and as a result, as shown in FIG.
As shown in, it is assumed that the lower surface 3a of the retainer ring 3 is worn by δ. In such a case, in the conventional carrier 200 shown in FIG. 12, the sheet 20 for pressing the wafer W is used.
Since 2 is integrally attached to the carrier 200,
The protrusion amount of the wafer W from the retainer ring 204 increases by δ from the initial value without the retainer ring 204 descending to the polishing pad 101 side. As a result, the polishing rate of the wafer W largely deviates from the polishing rate in the initial state.
I had to replace the 4. However, in the carrier 1 according to the polishing apparatus of this embodiment, the movable body 4 can freely move up and down with respect to the carrier body 2 by the action of the rotation transmission mechanism 6. Therefore, as shown in FIG. 10, when the retainer ring 3 to which a downward force is applied via the carrier body 2 is worn by δ, the movable body 4 rises relative to the carrier body 2 by δ, The amount of protrusion of W will be maintained at the initial value Δ.

As described above, according to the polishing apparatus of this embodiment, the pressure Pr applied to the retainer ring 3 of the carrier 1 is increased.
Since the pressure Pe applied to the outer peripheral portion Wa of the wafer W and the pressure P4 applied to the central portion of the wafer W can be respectively controlled, the polishing rate on the entire surface of the wafer W can be made uniform, and as a result, Therefore, the yield of the wafer W can be improved. Further, when the wafer W wears, the movable body 4 rises by the wear amount and automatically maintains the protrusion amount of the wafer W at the initial value Δ, so that the frequency of replacement of the retainer ring 3 due to wear can be drastically reduced. As a result, the operating rate of the polishing apparatus can be improved. Although air is used as the fluid in the above embodiment, it is needless to say that similar effects can be obtained by using a fluid such as oil. Further, the pressure chamber 5 as the first pressure chamber is formed by hermetically maintaining the gap between the lower surface 50a of the recess 50 and the upper surface 42a of the pressure receiving portion 42 by the seal members 51 and 52. As shown, the recess 50 is not provided in the carrier base 11, and the gap between the upper surface 4a of the movable body 4 and the lower surface 11d of the carrier base 11 is airtightly held by the seal members 51 and 52, thereby forming a first pressure chamber. It is also possible to form the pressure chamber 5'of. Furthermore, in the above-described embodiment, the flexible sheet 45 having a two-layer structure including a hard surface layer and a soft back layer (for example, IC1000 /
Since SUBA400) is used, in order to prevent overpolishing of the edge portion We of the wafer W, the retainer ring 3 is brought into contact with the polishing pad 101 and the pressing force Pr thereof is adjusted. However, when a softer and flexible sheet is used, the edge portion We of the wafer W does not suffer from overpolishing or underpolishing. Therefore, in this case, it is not necessary to contact the retainer ring 3 with the polishing pad 101. At this time, in the above formula (3), Pr
Since = 0, all the downward force Fd is applied to the pressure chamber 5 side. Therefore, only by adjusting the air pressure P5 in the pressure chamber 5, the entire surface of the wafer W can be uniformly polished.

[0023]

As described above in detail, according to the present invention, by pressing the carrier body with a predetermined force, the retainer ring can be pressed with the predetermined force, and the fluid of a predetermined pressure can be pressed. Is supplied to the first pressure chamber, the outer peripheral portion of the workpiece can be pressed at a pressure corresponding to the fluid pressure, and further, the fluid having a predetermined pressure is supplied to the second pressure chamber.
By supplying the fluid into the pressure chamber, the portion of the workpiece other than the outer peripheral portion can be pressed with a pressure corresponding to the fluid pressure. That is, the force applied to the retainer ring, the force applied to the outer peripheral portion of the workpiece, and the force applied to the central portion of the workpiece can be controlled respectively,
The entire surface of the work piece can be polished at a uniform polishing rate, and as a result, a work piece having a good yield can be provided, which is an excellent effect. When the lower surface of the retainer ring wears, the movable body relatively rises by the amount of wear of the retainer ring and maintains the amount of protrusion of the workpiece from the retainer ring at the initial amount of protrusion, that is, the retainer ring. Since the amount of protrusion of the workpiece is automatically adjusted during wear, it is not necessary to stop the polishing device and adjust or replace the retainer ring, which can improve the operating rate of the polishing device. There is also an effect.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a rotary drive mechanism.

FIG. 3 is a cross-sectional view showing the structure of a carrier.

FIG. 4 is an exploded perspective view of a carrier.

FIG. 5 is a partially enlarged view showing the structure of the rotation transmission mechanism.

FIG. 6 is a perspective view showing a flange.

FIG. 7 is a perspective view showing a partially broken structure of a hole.

FIG. 8 is an exploded perspective view of a movable body for clearly showing an air passage to the pressure chamber of the movable body.

FIG. 9 is a schematic cross-sectional view showing pressure applied to a retainer ring of a carrier, a wafer outer peripheral pressing portion and a flexible sheet.

FIG. 10 is a schematic cross-sectional view showing an automatic adjustment operation of a wafer protrusion amount.

FIG. 11 is a cross-sectional view showing a modified example of the carrier.

FIG. 12 is a sectional view showing an example of a conventional pneumatic carrier.

FIG. 13 is a partial enlarged view showing an over-polished state of the outer peripheral portion of the wafer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Carrier, 2 ... Carrier main body, 3 ... Retainer ring, 4 ... Movable body, 5 ... Pressure chamber, 6 ... Rotation transmission mechanism, 9-1, 9-2 ... Air pump, 10 ... Housing, 11 ... Carrier base, 40 ... Wafer outer peripheral pressing portion, 41 ... Pressure chamber, 42 ... Pressure receiving portion, 42a
... upper surface, 43 ... upper plate, 50 ... recessed portion, 50a ... lower surface,
61 ... Flange, 61a ... Projection, 62 ... Hole,
62a ... Vertical groove part, 90-1, 90-2 ... Air hose, 91-1, 91-2, 93-2 ... Vent hole, 92
-2 ... Groove, 100 ... Lower surface plate, 101 ... Polishing pad,
W ... Wafer, Wa ... Peripheral part.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeto Izumi             2647 Hayakawa, Ayase, Kanagawa Prefecture Speed Fam             Within the corporation F term (reference) 3C058 AA07 AA12 AB04 CB01 DA06                       DA17

Claims (4)

[Claims] 1. A retainer ring projecting from the outer periphery of the lower surface of a carrier body and capable of surrounding and holding a workpiece, and a retainer ring attached to the inside of said retainer ring so as to be vertically movable, and the lower surface portion of said retainer ring. A carrier comprising a movable body capable of contacting substantially the entire upper surface and a rotation transmission mechanism for rotating the movable body integrally with the carrier body, wherein a gap between the upper surface of the movable body and the lower surface of the carrier body is provided. Is used to form an airtight first pressure chamber, and a workpiece outer peripheral pressing portion capable of pressing the upper peripheral portion of the workpiece is projectingly provided on the lower surface portion of the movable body. A carrier characterized in that a second pressure chamber is formed by airtightly covering a space portion formed inside from below with a flexible sheet. 2. The carrier according to claim 1, wherein the rotation transmission mechanism is provided in a central portion of the carrier body and is provided in a central portion of an upper surface of the movable body and a hole opened toward the movable body. And a flange fitted in the hole, wherein the flange has a plurality of protrusions projectingly provided on its peripheral surface, and the hole has a plurality of protrusions of the flange that move up and down. A carrier comprising: a plurality of vertical groove portions that are engageable with each other; and a stopper portion that is located at the lowest position of the plurality of vertical groove portions and that receives the protrusion of the flange. 3. A rotatable lower surface plate, a retainer ring projecting from the outer periphery of the lower surface of the carrier body and capable of surrounding and holding a work piece on the lower surface plate from the outside, and vertically movable inside the retainer ring. A movable body which is attached and whose lower surface can contact substantially the entire upper surface of the workpiece, and a carrier having a rotation transmission mechanism for rotating the movable body integrally with the carrier body, and rotating while pressing the carrier. And a rotation drive means for rotating the carrier, wherein an airtight first pressure chamber is formed by using a gap between the upper surface of the movable body of the carrier and the lower surface of the carrier body, and the upper surface of the workpiece. A workpiece outer peripheral pressing portion capable of pressing the outer peripheral portion is provided on the lower surface of the movable body so as to project, and a space formed inside the workpiece outer peripheral pressing portion has a flexible sheet. A second pressure chamber is formed by airtightly covering it from below with a first fluid supply means capable of supplying a fluid to the first pressure chamber of the carrier and a fluid can be supplied to the second pressure chamber. And a second fluid supply means. 4. The polishing apparatus according to claim 3, wherein the rotation transmission mechanism of the carrier is provided in a central portion of the carrier main body, and has a hole opened to the movable body side and a central portion of an upper surface of the movable body. And a flange fitted in the hole, wherein the flange of the rotation transmitting mechanism has a plurality of protrusions protruding on its peripheral surface, and the hole of the rotation transmitting mechanism is A plurality of vertical groove portions in which the plurality of protrusion portions of the flange are vertically movably engaged, and a stopper portion that is located at the lowest position of the plurality of vertical groove portions and receives the protrusion portion of the flange. A polishing apparatus characterized by comprising: