Polishing head and polishing processing apparatus

Abstract

The invention provides a polishing head and a polishing processing apparatus, which can process wrinkles and star marks, can further improve SFQR on the surface of a substrate, and can stably polish a plurality of substrates with high quality. A polishing head (100) is provided with: a membrane support ring (3); a film (4) which covers the opening at the lower end side of the film support ring (3) and fixes the substrate (W) through a back film (5) attached to the surface side of the film support ring (3); and a retaining ring (6) that surrounds the film support ring (3) and is formed in a shape that surrounds the outer periphery of the substrate (W). On the inner surface side of the film (4), a plurality of radial ribs (4a) radially extending from the vicinity of the center thereof and annular ribs (4b) having a relatively smaller size than the film (4) are formed, and the radial ribs (4a) are radially formed outward from the annular ribs (4b). On the inner surface side of the elastic body, in a region surrounded by adjacent radial ribs (4a), membrane support rings (3), and annular ribs (4b), rib restraining members (33) having a shape that contacts the side surfaces of the radial ribs (4a), the inner peripheral surfaces of the membrane support rings (3), and the outer peripheral surfaces of the annular ribs (4b) are disposed.

Description

Technical Field

[0001] The invention relates to a grinding head and a grinding processing device, which are used for grinding processing of substrates such as semiconductor wafers or glass substrates. Background Art

[0002] In recent years, in the manufacturing process of semiconductor devices, along with the high integration of substrates such as semiconductor wafers and glass substrates (hereinafter referred to as wafers), the flattening technology of the substrate surface has become increasingly important. The most important of these flattening technologies is chemical mechanical polishing (CMP (Chemical Mechanical Polishing)). In this chemical mechanical polishing process, a polishing liquid containing abrasive particles such as silicon dioxide (SiO2) is supplied to a polishing surface (such as a polishing pad) using a polishing device (also called a polishing device), and the substrate is brought into sliding contact with the polishing surface to perform a polishing process.

[0003] For example, the CMP apparatus disclosed in Patent Document 1 is an apparatus that can suppress excessive increase in the pressure of the back film on the periphery of the wafer even when the template is worn and the thickness of the template gradually becomes thinner. Thus, even if the thickness of the template changes over time, it is possible to suppress significant fluctuations in the polishing rate at the periphery of the wafer compared to the polishing rate of other areas of the wafer.

[0004] In addition, the polishing head disclosed in Patent Document 2 applies a pressing force corresponding to the amount of pressure fluid sealed in the plurality of pressure chambers from each pressure chamber to the back side of the substrate, and applies the desired pressing force on the entire surface of the substrate to be processed without discontinuities, thereby making the outer diameter of the back film smaller than the outer diameter of the wafer, thereby preventing stress concentration at the end of the wafer. This can prevent uneven polishing, insufficient polishing, excessive polishing, etc. caused by uneven pressing force, and can significantly improve the deterioration of ESFQR (Edge Site Flont least Square Range), realizing high-quality production technology. Prior Art References Patent Documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-121650 Patent Document 2: Japanese Patent Application Publication No. 2014-018933 Summary of the invention Technical problem to be solved by the invention

[0006] In such a polishing processing device, if the relative speed and pressing force between the surface of the wafer to be polished (hereinafter referred to as the "polished surface") and the polishing pad are not uniform over the entire polished surface, uneven polishing such as insufficient polishing or excessive polishing will occur.

[0007] However, in the past, ESFQR improvement strategies have been developed for static pressure distribution, but research on wrinkle phenomenon and starmark phenomenon caused by the rotation of the platen and the grinding head is still weak. It is considered an urgent issue to understand these two dynamic phenomena and take countermeasures.

[0008] The wrinkle phenomenon is Fig.16 The phenomenon shown here refers to the phenomenon that the film is deformed and wrinkled due to the rotational force during the polishing process. The inventors analyzed the frictional motion that transmits the rotational motion to the wafer through the film. As a result, they found that multiple wrinkles in the form of involute curves were generated from the center of the film (see Fig.17 ).in addition, Fig.17 This is a diagram of the wrinkle pattern produced by transferring the film onto an involute curve. The study also shows that depending on the number of wrinkles, the wrinkle pattern can be a pattern similar to a typhoon vortex or a vortex state.

[0009] Specifically, the wrinkling phenomenon is caused by the expansion of the membrane and the separation of the wafer, resulting in a change (reduction) in the process pressure (see Fig.18 In order to reduce this phenomenon, it is necessary to prevent the film from wrinkling. That is, as a wrinkle countermeasure, a mechanism that can prevent shear deformation in the film surface is required.

[0010] In addition, the star mark phenomenon Fig.19 As shown, this is caused by the gap between the wafer outer diameter and the retaining ring inner diameter. In addition, Fig. 20 (a) and (b) are diagrams showing examples of Δθ analysis. When the wafer is subjected to the rotational friction force from the pressure plate (pad), the outer diameter of the wafer contacts the inner diameter of the retaining ring (see Fig. 20 (a)). At the contact point, with B as the fulcrum, the CCW=CW state is achieved. Due to the friction between the wafer and the retaining ring, the wafer moves to point A at the same speed ωr as the retaining ring (see Fig. 20 B).

[0011] However, at point A, CCW exceeds CW and friction static force, and returns to point B through relative rotation. When returning to point B, the wafer undergoes relative rotation ωws, and the wafer rotation repeats the following process: Due to this relative rotation, in the AOB area of ​​the wafer, a fan-shaped valley shape is formed in which the concave shape deepens in the peripheral direction due to the phenomenon that the RR (Removal Rate) becomes larger than that of the adjacent area of ​​the same radius. The period of this relative rotation motion varies according to the ratio of the platen diameter (Pd) to the wafer diameter (Sd). In a general-purpose machine, Sd / Pd is about 0.4, and under this condition, the period of one rotation of the retaining ring is about 5. Therefore, a star-shaped (pentagonal) pattern is observed in the RR contour map of 5 cycles (see Fig.19 ).

[0012] Therefore, in order to further improve the SFQR of the wafer surface and perform high-quality and stable polishing of a large number of wafers, it is necessary to deal with the star mark phenomenon and the wrinkle phenomenon.

[0013] The main purpose of the present invention is to provide a grinding head and a grinding processing device that can handle wrinkle phenomena, star mark phenomena, etc. that have not been elucidated so far, and can further improve the SFQR of the chip surface, so as to perform high-quality and stable grinding on a large number of chips. Problem Solving Unit

[0014] A grinding processing device, characterized in that it comprises: a grinding table having a grinding pad; a grinding head that holds a substrate to be ground so that the grinding surface of the substrate is in sliding contact with the grinding pad; the grinding head comprises: an annular body having an inner circumference of a size that can surround the outer circumference of the substrate to be ground; an elastic body that covers the lower end opening of the annular body and holds the substrate by a backing film attached to the surface side of the elastic body; a holding ring that wraps the annular body and is formed into a shape that surrounds the outer circumference of the substrate; a driving A unit is used to horizontally rotate the annular body and the retaining ring as a whole, and the inner side of the elastomer is provided with a plurality of radial ribs extending radially from near its center and annular ribs whose size is relatively smaller than that of the elastomer, and the radial ribs are radially formed outward from the annular ribs. On the inner side of the elastomer, in an area surrounded by adjacent radial ribs, the annular body and the annular ribs, a rib restraint component is provided, and the rib restraint component is formed in a shape that contacts the side surfaces of the radial ribs, the inner peripheral surface of the annular body, and the outer peripheral surface of the annular ribs.

[0015] The present invention also relates to a grinding head, characterized in that the grinding head is arranged in a grinding processing device with a horizontally rotating grinding pad, and includes: an annular body having an inner circumference of a size that can surround the outer circumference of the substrate to be ground; an elastomer, covering the lower end side opening of the annular body, fixing the substrate by a back film attached to the surface side of the elastomer; a retaining ring, which encloses the annular body and is shaped to surround the outer circumference of the substrate; a driving unit, which is used to rotate the annular body and the retaining ring horizontally as a whole; on the inner side of the elastomer, a plurality of radial ribs extending radially from near the center and an annular rib whose size is relatively smaller than the size of the elastomer are formed; the radial ribs are formed radially outward from the annular ribs, and a rib restraint component is provided in an area surrounded by adjacent radial ribs, the annular body and the annular ribs on the inner side of the elastomer, and the rib restraint component is formed in a shape that contacts the side surface of the radial rib, the inner peripheral surface of the annular body and the outer peripheral surface of the annular rib. Effects of the Invention

[0016] According to the present invention, a grinding head and a grinding processing device can be provided, which can handle the wrinkle phenomenon and star mark phenomenon that have not been elucidated so far, and can further improve the SFQR of the chip surface, so that multiple chips can be ground with high quality and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram for explaining an example of a polishing head and its peripheral structure included in a polishing processing apparatus. Figure 2 It is a schematic longitudinal sectional view for explaining an example of a polishing head and its peripheral structure provided in a polishing processing apparatus. Figure 3 It is a three-dimensional schematic diagram for explaining an example of the structure of a membrane and a membrane support ring. Figure 4 It is a cross-sectional schematic diagram for explaining an example of the structure of a membrane and a membrane support ring. Figure 5 It is a perspective schematic diagram for explaining an example of the structure of a rib restraint component. Figure 6 This is a perspective schematic diagram for explaining an example of a restraint and restriction mechanism that connects a plurality of rib restraint members disposed on the back side of a membrane. Figure 7 This is a schematic perspective view for explaining an example of a rib structure. Figure 8 This is a plan view for explaining an example of a state in which a plurality of rib restraining members and a restraining and limiting mechanism are arranged on the back side of a membrane. Fig. 9 It is a diagram for explaining another structure of the film. Fig.10 is used to illustrate an example with Fig. 9 A diagram of another structure of a different membrane. Fig.11 (a) is a schematic longitudinal sectional view for explaining an example of an adjustment mechanism of a retaining ring; (b) is a schematic plan view for explaining an example of an adjustment mechanism of a retaining ring. Fig.12 Yes means Fig.11 A top view schematic diagram of a specific structure of an example of a retaining ring is shown. Fig.13 (a) and (b) are schematic plan views for explaining an example of an adjustment mechanism for adjusting the diameter dimension of the retaining ring 6. Fig.14 (a) is used to illustrate an example Fig.12 (b) is a perspective view of an adjustment mechanism for different retaining rings; Fig.12 Schematic top view of different retaining ring adjustment mechanisms. Fig.15 (a), (b), (c), and (d) are examples. Fig.14 The specific structure of the retaining ring is shown in the figure. Fig.16 This is a diagram for explaining the phenomenon of wrinkling. Fig.17 This is a diagram showing an example of an involute curve. Fig.18 This is a diagram showing an example of the film floating phenomenon. Fig.19 This is a diagram for explaining the phenomenon of star marks. Fig. 20 (a) and (b) are diagrams showing an example of Δθ analysis. Fig.21 FIG. 1 is a diagram showing an example of angular velocity lines. DETAILED DESCRIPTION

[0018] The embodiment of the present invention will be described below with reference to the accompanying drawings. In addition, the grinding processing device of this embodiment uses a substrate such as a semiconductor wafer or a glass substrate (hereinafter sometimes referred to as a wafer) as a grinding object. In this specification, one surface of the substrate is referred to as a circular or substantially circular grinding surface. In addition, the surface of the grinding pad that contacts the grinding surface of the wafer is referred to as a grinding surface.

[0019] A grinding processing device comprises: a grinding table, to which a grinding pad as a grinding component is bonded, and used to horizontally rotate the grinding pad; and a grinding head, which is used to make the grinding surface of a substrate face the grinding pad and make sliding contact with it. The substrate is pressed against the polishing pad by the polishing head. Then, while polishing liquid (slurry) is supplied to the polishing pad, the polishing table and the polishing head are rotated, thereby performing a polishing process on the polished surface.

[0020] [Example] Figure 1 It is a schematic structural diagram of the polishing processing device S according to this embodiment. Figure 1 The polishing apparatus S shown in the figure includes a polishing table 51 , and a polishing pad 50 is bonded to the surface of the polishing table 51 .

[0021] The polishing processing device S also includes: a control unit 20, which includes: a polishing head 100, which holds the substrate (wafer) W and presses the polished surface onto the polishing pad 50; a nozzle N, which is used to supply polishing liquid to the polishing pad 50; a motor (not shown), which is used to horizontally rotate the polishing table 51 and the polishing head 100 respectively; a polishing liquid supply mechanism (not shown), which is connected to the nozzle N; and a computer, which is used to control the driving unit including the motor.

[0022] The polishing pad 50 is in the shape of a disk, and its radius is larger than the maximum diameter (diameter) of the polished surface of the wafer W. In this mechanism, the rotation speed and rotation direction of the polishing pad 50 and the polishing head 100 are changed, so that it becomes a mechanism capable of adjusting the relative polishing speed within the surface of the wafer W. In addition, the polishing pad 50 itself has elasticity, and a material made of non-woven fabric, a material made of foamed polyurethane, etc., which is available on the market, can be used.

[0023] The polishing head 100 includes: a holding mechanism for holding the wafer W so that its polishing surface is in sliding contact with the polishing pad 50; and a pressing mechanism for applying pressure from the back side (back side) of the polished surface of the held wafer W toward the polishing pad 50. The details of these mechanisms will be described later.

[0024] The control unit 20 mainly positions the nozzle N, controls the nozzle N to start or stop supplying the polishing liquid, controls the supply amount per unit time of the polishing liquid ejected from the nozzle N, and controls the start and stop of the motor. The rotational force of the motor controlled by the control unit 20 is transmitted to the polishing table 51 via a driving unit (not shown). As a result, the polishing table 51 rotates horizontally or stops rotating. The rotational force (torque) of the motor is also transmitted to the polishing head 100 via a driving unit (eg, a universal joint) not shown in the figure. As a result, the polishing head 100 is horizontally rotated or stops rotating.

[0025] The rotation direction of the grinding table 51 and the rotation direction of the grinding head 100 are usually the same. This is because if the grinding direction is reversed, the grinding relative speed in the wafer surface becomes uneven, and uniform grinding may not be performed. The grinding accuracy can be improved by setting the rotation direction of the grinding table 51 and the rotation direction of the grinding head 100 to the same direction and adjusting the rotation speeds of the two.

[0026] In addition, the rotational force of the single motor can be transmitted to the grinding table 51 and the grinding head 100 through gears with different gear ratios, or the rotational force can be transmitted separately through separate motors. Both can be designed as needed. The control sequence of the control unit 20 will be described later.

[0027] Under the control of the control unit 20 , when the rotation speed of the polishing table 51 reaches a predetermined value, the polishing liquid is supplied from the nozzle N to the polishing pad 12 for a predetermined time. Next, the polishing head 100 included in the polishing apparatus S and its peripheral structure will be described in detail.

[0028] [Grinding head and its surrounding structure] Figure 2 FIG. 1 is a schematic longitudinal cross-sectional view for explaining an example of a polishing head 100 and its peripheral structure included in a polishing processing apparatus S. Figure 2 An example of the structure of the polishing head 100 will be described. In addition, in order to further improve the performance of the chip surface such as GBIR (Global backside idealrange), the grinding head 100 holds the chip W so that its ground surface is in sliding contact with the grinding pad 50 under the pressure controlled by the grinding processing device S, and applies pressure to the held chip W from the back direction (back side) of the ground surface toward the grinding pad 50.

[0029] [Structure of grinding head] like Figure 2 As shown, the polishing head 100 generally has a holding mechanism for making the wafer W to be polished slide in contact with the polishing pad 50 under a state where a polishing pressure (processing pressure) is applied to the wafer W. The polishing head 100 also has a pressurizing mechanism for applying the polishing pressure (processing pressure) (P1) and pressing the holding ring 6 toward the polishing pad 50 side (P2).

[0030] As described above, the polishing head 100 included in the polishing processing apparatus S is configured to supply a pressure fluid (e.g., compressed air) to the pressure chamber through an air pipe connected to a fluid supply mechanism (not shown) or to be able to recover the supplied pressure fluid. That is, the polishing head 100 is configured to be able to generate a processing pressure applied to the wafer W by adjusting the amount of the pressure fluid supplied to the pressure chamber.

[0031] In addition, the retaining ring 6 in this embodiment is used to prevent the wafer W from flying outward in the peripheral direction due to the rotational force of the polishing head 100 and the polishing table 51. In addition, the retaining ring 6 is also related to the contact pressure between the wafer end and the polishing pad 50.

[0032] The polishing head 100 includes a main head frame 1 , a sub-head frame 2 , a film support ring 3 , a film 4 , a back film 5 , a holding ring 6 (four holding parts 6 a ), and a rotating frame 7 .

[0033] The polishing head 100 is configured to transmit a driving force (eg, a rotational force (torque) of a motor as a starting unit) through various components connected to the head frame 1. Specifically, the retaining ring 6 is connected to the film support ring 3 via the driving pin 8. Thereby, various components of the polishing head 100 can be integrally rotated horizontally or stopped. In addition, the control unit 20 controls the start and stop of the rotation, the amount of rotation per unit time, and the like according to preset contents.

[0034] The membrane support ring 3 is an annular body formed using, for example, a SUS material or the like. The film 4 covers the lower end opening of the film support ring 3 (annular body 3 ), and holds the wafer W via a backing film 5 bonded to the surface thereof. The membrane 4 is a cylindrical elastic body (tub-shaped elastic body) having an inner diameter capable of being fitted on the outer peripheral surface of the membrane support ring 3 and having a substantially cylindrical (pot-shaped) shape. The membrane 4 can also be formed of a rubber material having excellent strength and durability, such as ethylene propylene rubber (EPDM) and silicone rubber. Here, an example of the structure of the film 4 and the film support ring 3 that function as a holding mechanism for holding the wafer W, and details of the surrounding structure will be described.

[0035] Figure 3 It is a perspective schematic diagram for explaining an example of the structure of the membrane 4 and the membrane support ring 3. Figure 4 It is a schematic cross-sectional view for explaining an example of the structure of the membrane 4 and the membrane support ring 3. Figure 5 It is a perspective schematic diagram for explaining an example of the structure of the rib restraint member 33. Figure 6 It is a perspective schematic diagram for explaining an example of a restraint and restriction mechanism 31 ( 32 ) connecting a plurality of rib restraint members 33 arranged on the back side of the film 4 . Figure 7 This is a schematic perspective view for explaining an example of a rib structure. Figure 8 This is a plan view for explaining an example of a state in which a plurality of rib restraining members 33 and a restraining and limiting mechanism 31 ( 32 ) are arranged on the back side of the film 4 . Below, use Figures 3 to 8 The structure of an example of the rib according to the present invention will be described in detail.

[0036] like Figure 3 , Figure 4 As shown, the grinding head 100 includes: a film support ring 3 (annular body 3), which has an inner circumference of a size capable of surrounding the outer circumference of a substrate W that is a grinding process object; and a film 4, which covers the opening portion on the lower end side of the annular body and holds the substrate W by a back film attached to its surface side.

[0037] In addition, if Figure 7 As shown, on the back side of the film 4, a plurality of radial ribs 4a extending radially from the vicinity of the center and an annular rib 4b having a size relatively smaller than the film 4 are formed. The radial ribs 4a are formed radially outward from the annular rib 4b. In addition, if Figure 5 and Figure 4 , Figure 8 As shown, rib restraint members 33 are respectively arranged in the area surrounded by the adjacent radial ribs 4a, the membrane support ring 3 (annular body 3) and the annular ribs 4b. The rib restraint members 33 are formed in a shape that contacts the side surface of the radial ribs 4a, the inner peripheral surface of the membrane support ring 3 (annular body 3) and the outer peripheral surface of the annular ribs 4b.

[0038] In addition, Figure 3 Five rib restraining parts 33 are arranged in the film 4, but the number is not limited to this. For example, there are also cases where four rib restraining parts 33 are arranged or six rib restraining parts 33 are arranged. In this case, radial ribs 4a corresponding to the number of rib restraining parts 33 used (arranged) are formed on the inner side of the film 4. In addition, the number of rib restraining parts 33 can also be determined according to the number of radial ribs 4a formed on the inner side of the film 4.

[0039] As described above, a plurality of radial ribs 4a (see FIG. 1 ) extending radially from the vicinity of the center of the back side of the film 4 are formed on the back side of the film 4. Figure 7 ). In addition, a circular rib 4b is formed whose size is relatively smaller than that of the membrane 4. Figure 7 As shown, the radial ribs 4a are radially formed outward from the annular ribs 4b. The radial ribs 4a and the annular ribs 4b are, for example, integrally formed with the membrane 4 using the same material. In addition, the height and width of the radial ribs 4a and the annular ribs 4b can be the same or can be set arbitrarily.

[0040] like Figure 5As shown, the rib restraint member 33 is formed in a shape that contacts the side surface of the radial rib 4a, the inner peripheral surface of the membrane support ring 3 (annular body 3), and the outer peripheral surface of the annular rib 4b in the area surrounded by the adjacent radial ribs 4a, the membrane support ring 3 (annular body 3), and the annular rib 4b. The rib restraint member 33 is a frame body formed of a resin material or the like in a substantially fan-shaped shape. The rib restraint member 33 has grooves 33a and 33b. The grooves 33a and 33b are recesses for placing the rod-shaped body 32 of the restraint restriction mechanism described later.

[0041] like Figure 5 , Figure 8 As shown, the radial rib 4a of the membrane 4 is sandwiched by a pair of adjacent rib restraining members 33 provided on the inner side of the membrane 4. Therefore, the rib restraining members 33 are sized to be in contact with the inside of the membrane support ring 3 (annular body 3), and as shown in FIG. Figure 5 As shown, it is formed in a size that can form a space corresponding to the width dimension A of the radial rib 4a.

[0042] In this way, the radial ribs 4a are clamped by the adjacent pair of rib restraint members 33, so that the radial ribs 4a can be prevented from being deformed in the rotational direction due to the rotational force during the grinding process. That is, the rib restraint members 33 restrain the radial ribs 4a to prevent deformation due to the rotational force, thereby limiting their movement. Furthermore, the deformation of the annular rib 4b in the rotational direction due to the rotational force during the grinding process can be prevented by the rib restraint member 33. That is, the rib restraint member 33 restrains the annular rib 4b from deformation due to the rotational force, thereby restricting its movement.

[0043] In this way, the radial ribs 4a and the annular ribs 4b are constrained by the rib constraining member 33 so that they do not "move" due to the rotational force during the grinding process, thereby preventing the film 4 from being deformed and wrinkled due to the rotational force during the grinding process. That is, the radial ribs 4a, which are elastic bodies, are prevented from deforming in the rotational direction, thereby preventing the surface of the film 4 from wrinkling in the area between the adjacent radial ribs 4a, and the occurrence of wrinkles on the entire surface of the film 4 can be effectively suppressed. In the polishing head 100 according to the present embodiment, it is possible to effectively suppress the phenomenon in which the film 4 is deformed and wrinkled due to the rotational force during the polishing process.

[0044] Furthermore, even when such rib restraint members 33 are provided, the radial ribs 4a and the annular ribs 4b are not restrained in the vertical direction and can move freely. Therefore, grinding pressure (processing pressure) (P1) can be applied to the lower surface sides of the radial ribs 4a and the annular ribs 4b.

[0045] In the conventional mechanism, the rotation phase of the outer periphery of the membrane is synchronized with the membrane ring, but the rotation phase of the center lags behind, thus producing an involute curve-shaped wrinkle phenomenon. In contrast, in the polishing head 100 of the present embodiment, the rib restraining member 33 restrains the radial rib 4a in the direction of the rotation angle θ and restrains the annular rib 4b in the direction of the radius r. Therefore, the outer periphery and the center of the film 4 rotate synchronously, and shear deformation does not occur, thereby preventing wrinkles from occurring.

[0046] In addition, Figure 3 , Figure 4 etc., shows an example in which a rib restraint component 33 formed in a shape that contacts the outer peripheral surface of the annular rib 4b, the radial rib 4a, and the inner peripheral surface of the membrane support ring 3 is arranged in an area surrounded by the annular rib 4b, the adjacent radial rib 4a, and the membrane support ring 3, but the structure is not limited to this.

[0047] For example, in a case where a plurality of radial ribs 4a extending radially from near the center of the membrane 4 are formed on the inner side thereof, a rib restraint component 33 having a shape in contact with the radial ribs 4a and the inner circumferential surface of the membrane support ring 3 is formed in an area surrounded by adjacent radial ribs 4a and the membrane support ring 3.

[0048] In addition, if Figure 6 and Figure 3 , Figure 4 As shown, the grinding head 100 has a restraint and restriction mechanism 31 (32) connecting the film support ring 3 and the rib restraint member 33. Specifically, for example, the film support ring 3 is formed with a plurality of grooves 3a on its inner peripheral surface, and the restraint and restriction mechanism 31 (32) can be configured to include the following structures: a disc body 31, the size of which can be accommodated in the inner peripheral area of ​​the circular ring rib 4b; and a rod-shaped body 32, which extends outward from the disc body 31 and the ends of which are respectively engaged with the grooves 3a.

[0049] Thus, the disk body 31 and the rod-shaped body 32 function as a restraining and limiting unit connecting the film support ring 3 and the rib restraining member 33. Therefore, the film 4 and the film support ring 3 and their surroundings can cope with wrinkles, and the SFQR of the substrate surface can be further improved.

[0050] Fig. 9 This is a diagram for explaining another structure of the film 4 . exist Fig. 9 The film 40 shown has a plurality of annular ribs 40a formed on the inner side thereof, each of which is relatively smaller than the film 40. The inner and outer peripheral surfaces of the annular ribs 40a are partially or entirely covered with annular rib restraint members R1 (R1 to R8).

[0051] The annular rib restraints R1 (R1 to R8) can prevent deformation of the annular rib 40a due to rotational force during grinding. That is, the annular rib restraints R1 (R1 to R8) restrain the annular rib 40a from deformation due to rotational force, thereby limiting its movement. By preventing the elastic annular ribs 40 a from being deformed by the rotational force, wrinkles are prevented from occurring on the surface of the film 4 in the region between the adjacent annular ribs 40 a , and the occurrence of wrinkles on the entire surface of the film 4 can be effectively suppressed.

[0052] Even the film 40 having such a structure can cope with the wrinkling phenomenon, and can further improve the SFQR and the like of the substrate surface. Even when the annular rib restraining member R1 (R1 to R8) is provided, the annular rib 40a can freely move in the vertical direction, so that grinding pressure (processing pressure) (P1) can be applied to the lower surface side of the annular rib 40a.

[0053] Fig.10 This is a diagram for explaining another structural example of the film 40 described above. exist Fig.10 The inner side of the film 40 shown is formed with a plurality of annular ribs 40a, each of which is formed with a size relatively smaller than the size of the film 40. In addition, annular rib restraint parts R10 (R10 to R13) are formed with the same size as the inner side area of ​​the film 40 sandwiched between each adjacent annular rib 40a, and holes are formed on the surface of the annular rib restraint parts R10 (R10 to R13), and the annular rib restraint parts R10 (R10 to R13) are respectively arranged in each of the inner side areas.

[0054] The annular rib restraints R1 (R1 to R8) can prevent deformation of the annular rib 40a due to rotational force during grinding. That is, the annular rib restraints R1 (R1 to R8) restrain the annular rib 40a from deformation due to rotational force, thereby limiting its movement. By preventing the elastic annular ribs 40 a from being deformed by the rotational force, wrinkles are prevented from occurring on the surface of the film 4 in the region between the adjacent annular ribs 40 a , and the occurrence of wrinkles on the entire surface of the film 4 can be effectively suppressed.

[0055] Even the film 40 having such a structure can cope with the wrinkling phenomenon, and can further improve the SFQR and the like of the substrate surface. In addition, even when the annular rib restraining member R10 (R10 to R13) is configured, the annular rib 40a can freely move in the vertical direction, so it is also possible to apply a grinding pressure (processing pressure) (P1) to the lower surface side of the annular rib 40a. In addition, since the annular rib restraining member R10 (R10 to R13) is formed with a hole, the film 40 can be easily loaded and unloaded.

[0056] In addition, Figure 2 The back film 5 shown in the figure is a film-like film stretched on the outer bottom surface (outer surface) of the film 4. For example, a porous material such as a non-woven fabric can be used as its material. The back film 5 makes the polished surface of the wafer W face (contact) with the polishing pad 50 and holds the wafer W in a sliding contact state. In this way, the film 4 and the back film 5 function as a holding mechanism for fixing the wafer W.

[0057] Among them, through the analysis of the inventors of this application, it was found that the star mark phenomenon is generated when there is a gap between the substrate and the retaining ring. Therefore, as a countermeasure, it is necessary to reduce the gap. However, if the gap is small, it becomes difficult to install and separate the substrate, so it is found that the retaining ring needs to have an opening and closing function. Hereinafter, as an example in which the retaining ring has an opening and closing function, an adjustment mechanism capable of changing the diameter dimension of the retaining ring will be described.

[0058] Fig.11 is a schematic diagram for explaining an example of an adjustment mechanism of a retaining ring; Fig.11 (a) is a schematic longitudinal section view; Fig.11 (b) is a schematic top view. Fig.12 Yes means Fig.11 A top view schematic diagram of a specific structure of an example of a retaining ring is shown. Fig.13 It is a schematic plan view for explaining an example of an adjustment mechanism for adjusting the diameter dimension of the retaining ring 6 . Fig.13 (a) shows the closed state of the retaining ring, Fig.13 (b) shows the open state of the retaining ring. Specifically, the retaining member 6a is moved outward to change the diameter of the retaining ring 6 ( Fig.13 (b)) is regarded as the open state, and the state in which the diameter is restored to the original size is regarded as the closed state ( Fig.13 (a)).

[0059] The retaining ring 6 is formed to surround the outer circumference of the wafer W. The retaining ring 6 not only restricts the wafer W from being ejected outward due to the rotational force of the polishing head 100 and the polishing table 51 , but also controls the contact pressure between the wafer end and the polishing pad 50 .

[0060] Specifically, in the polishing head 100, during the polishing process, a gap is formed between the end of the wafer W and the inner wall of the inner circumference of the retaining ring 6. In addition, the "pad pressing" in which the surface of the polishing pad 50 is pressed by the retaining ring 6 can be functionally performed with high accuracy. In this way, the retaining ring 6 functions as one of the pressing mechanisms of the polishing head 100.

[0061] like Fig.11 , Fig.12 , Fig.13 As shown, the retaining ring 6 is composed of four retaining parts 6a forming a fan shape. In addition, as one of the peripheral structures of the retaining ring 6, there is an adjustment mechanism that can move each retaining part 6a outward based on the diameter center of the retaining ring 6 to change the diameter size of the retaining ring 6. Adjustment mechanism, for example, Figure 2 , Fig.12 As shown in FIG. 1 , the structure can be configured to include: a rotating frame 7, a rotary action gear 10, an adjustment guide rail 12, an arc portion 61 formed on the holding member 6a (see FIG. 1 ). Figure 2 , Fig.12 ), motor M.

[0062] The rotating frame 7 is configured to rotate horizontally together with the membrane support ring and the retaining ring 6. Fig.12 As shown, the peripheral surface of the rotating frame 7 has a gear structure, and can rotate within a predetermined range by a rotating gear 10 and a motor M. The rotating gear 10 and the motor M function as a rotating unit for rotating the rotating frame 7 .

[0063] Each holding member 6a has an arc portion 61 formed with a curvature different from the curvature of the holding member 6a based on the diameter center of the holding ring 6. The rotating frame 7 has an adjustment guide 12 composed of a pair of rollers (e.g., bearings) that clamp each arc portion 61. In this way, the adjustment guide 12 functions as a clamping unit that clamps the arc portion 61. The adjustment mechanism controls the motor M to rotate the rotating frame 7 within a predetermined range, thereby moving the holding member 6 a outward, thereby functioning as an adjustment unit that changes the diameter size of the holding ring 6 .

[0064] Thus, the "gap" generated between the end of the wafer W and the inner wall of the inner circumference of the retaining ring 6 can be adjusted during the grinding process. In this way, the retaining ring 6 and its surroundings can cope with the occurrence of star marks, and further improvements in SFQR of the substrate surface can be achieved.

[0065] In addition, in the polishing head 100 provided in the polishing processing apparatus S, as shown in FIG. Figure 2 As shown, an airbag P2 is arranged between the head frame 2 and the holding ring 6 . In the polishing head 100 included in the polishing processing device S, a pressure fluid (e.g., compressed air) is supplied to the air bag P2 through an air pipe connected to a fluid supply mechanism (not shown), or the supplied pressure fluid can be recovered. That is, the polishing head 100 is configured to generate a pressure P2 for pressing the surface of the polishing pad 50 by the retaining ring 6 by adjusting the amount of the pressure fluid supplied to the air bag P2.

[0066] The airbag P2 is annular and expands when the pressure fluid is sealed in the airbag P2. Thus, the holding ring 6 can press the polishing pad 50 with the pressure P2 corresponding to the amount of the sealed pressure fluid. These structures function as a pressure adjustment unit for adjusting the pressure P2 applied by the holding ring 6 to the polishing pad 50 by adjusting the amount of pressure fluid supplied to the airbag P2 through the control unit 20. In other words, the pressure adjustment unit can also be said to be provided for optimizing the stress on the wafer end.

[0067] The polishing head 100 and the polishing processing device S having the polishing head involved in this embodiment can deal with wrinkle phenomenon, star mark phenomenon, etc., can further improve the SFQR of the substrate surface, and can perform a large amount of polishing processing with high quality and stability.

[0068] [Modifications] Fig.14 is used to illustrate an example with Fig.12 Schematic diagram of the adjustment mechanism of different retaining rings. Fig.14 (a) Schematic diagram; Fig.14 (b) is a schematic top view. Fig.15 It is shown Fig.14 FIG. 2 is a diagram showing an example of a specific structure of a retaining ring. In addition, about the structure which has already been described, the same code|symbol is attached|subjected and the description is abbreviate|omitted.

[0069] Fig.15 (a) and (c) show the closed state of the retaining ring. Fig.15 (b) and (d) show the open state of the retaining ring. Specifically, the retaining member 6a is moved outward to change the diameter of the retaining ring ( Fig.15 (b) and (d)) are regarded as the open state, and the state restored to the original diameter size is regarded as the closed state ( Fig.15 (a), (c)).

[0070] like Fig.14 , Fig.15As shown, the retaining ring is composed of four retaining parts 6a formed in a fan shape. In addition, as one of the peripheral structures of the retaining ring, there is an adjustment mechanism for moving each retaining part 6a outward based on the diameter center of the retaining ring to change the diameter size of the retaining ring.

[0071] Adjustment mechanism, for example, Fig.14 , Fig.15 As shown, the annular frame 22 includes a guide plate 22 formed in an annular shape, a guide hole 22a formed in the guide plate 22, a guide pin 21 formed in the holding member 6a, and a motor (not shown) for rotating the annular frame 22. The guide hole 22a is formed with a curvature different from the curvature of the holding member 6a based on the diameter center of the holding ring. The holding member 6a of the holding ring is connected by a spherical connecting member 20 at the respective opposing sides. In this way, the adjustment mechanism functions as adjustment means for changing the diameter dimension of the retaining ring 6 .

[0072] Thus, the "gap" generated between the end of the wafer W and the inner wall of the inner circumference of the retaining ring can be adjusted during the grinding process. In this way, the retaining ring and its surroundings can cope with the occurrence of star marks, and further improvements in SFQR of the substrate surface can be achieved.

[0073] The above-described embodiments are for explaining the present invention more specifically, and the scope of the present invention is not limited to these examples.

Explanation of symbols

[0074] 1(2)…head frame, 3…membrane support ring (annular body), 3a…groove portion, 4…membrane (elastic body), 4a…radial rib, 4b…annular rib, 5…back membrane, 6…retaining ring, 6a…retaining component, 7…rotating frame, 10…rotating action gear, 12…adjusting guide rail, 20…control portion, 31…disc body, 32…rod-shaped body, 33…rib restraining component, 40a…annular rib, 50…polishing pad, 51…polishing table, 61…arc portion, 100…polishing head, S…polishing processing device, N…nozzle, R1~R13…annular rib restraining component, W…wafer.

Claims

1. A grinding device, characterized in that: The grinding processing device comprises: A grinding table having a grinding pad; A polishing head holds a substrate to be polished so that a polished surface of the substrate is in sliding contact with the polishing pad; The grinding head comprises: An annular body having an inner diameter large enough to surround the outer periphery of the substrate to be polished; An elastic body covering the lower end opening of the annular body and holding the substrate via a backing film attached to the surface side of the elastic body; A retaining ring encloses the annular body and is formed into a shape surrounding the outer periphery of the substrate; a driving unit, used to rotate the annular body and the retaining ring horizontally as a whole, On the inner side of the elastic body, a plurality of radial ribs extending radially from the vicinity of the center thereof and an annular rib having a size relatively smaller than that of the elastic body are formed, and the radial ribs are formed radially from the annular rib toward the outside. A rib restraint component is provided in an area surrounded by adjacent radial ribs, the annular body and the circular rib on the inner side of the elastic body. The rib restraint component is formed into a shape that contacts the side surface of the radial rib, the inner peripheral surface of the annular body, and the outer peripheral surface of the circular rib.

2. The grinding device according to claim 1, characterized in that: The grinding processing device includes a restraining and limiting unit for connecting the annular body and the rib restraining member.

3. The grinding device according to claim 2, characterized in that: A plurality of grooves are formed on the inner peripheral surface of the annular body. The constraint limiting unit comprises: a disc body having a size capable of being received within the inner circumference of the disc; and The rod-shaped body is formed to extend outward from the disc body and has its ends engaged with the grooves.

4. The grinding device according to claim 1, characterized in that: A plurality of annular ribs are respectively formed on the inner side of the elastic body, and the size of the annular ribs is relatively smaller than the size of the elastic body; An annular rib restraint member is disposed on the rear surface side of the elastic body, and the annular rib restraint member covers a part or all of the inner peripheral surface and the outer peripheral surface of each of the annular ribs.

5. The grinding device according to claim 1, characterized in that: A plurality of annular ribs are respectively formed on the inner side of the elastic body, and the size of the annular ribs is relatively smaller than the size of the elastic body; An annular rib restraint component is provided in the back side region of the elastic body. The annular rib restraint component is formed to have the same size as the back side region of the elastic body sandwiched between each of the adjacent annular ribs, and a hole is formed on the surface of the annular rib restraint component.

6. The grinding device according to any one of claims 1 to 5, characterized in that: The retaining ring is composed of a plurality of retaining parts formed in a fan shape, and has an adjusting unit that moves each retaining part toward the outside based on the diameter center of the retaining ring to change the diameter size of the retaining ring.

7. The grinding device according to claim 6, characterized in that: The grinding processing device has a rotating frame that rotates horizontally integrally with the annular body and the retaining ring; Each of the retaining members has an arc portion formed with a curvature different from the curvature of the retaining member based on the diameter center of the retaining ring; The rotating frame has clamping units that respectively clamp the arc parts; The adjustment unit controls the rotation unit to rotate the rotating frame within a predetermined range, thereby moving the holding member outward to change the diameter size of the holding ring.

8. The grinding device according to claim 6, characterized in that: The retaining components are connected to the annular body through driving pins, respectively.

9. A grinding head, the grinding head being arranged in a grinding processing device having a horizontally rotating grinding pad, characterized in that: include: An annular body having an inner diameter large enough to surround the outer periphery of the substrate to be polished; An elastic body covering the lower end opening of the annular body and holding the substrate via a backing film attached to the surface side of the elastic body; A retaining ring encloses the annular body and is formed into a shape surrounding the outer periphery of the substrate; A driving unit, used to rotate the annular body and the retaining ring horizontally in an integrated manner; The inner side of the elastic body is formed with a plurality of radial ribs extending radially from the vicinity of the center thereof, and an annular rib whose size is relatively smaller than the size of the elastic body; the radial ribs are formed radially from the annular rib toward the outside, A rib restraint component is provided in an area surrounded by adjacent radial ribs, the annular body and the circular rib on the inner side of the elastic body. The rib restraint component is formed into a shape that contacts the side surface of the radial rib, the inner peripheral surface of the annular body, and the outer peripheral surface of the circular rib.

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