CMP device

Abstract

To provide a CMP device capable of lengthening an operation time of the CMP device while suppressing chipping of a work-piece at the time of performing a CMP grinding.SOLUTION: A CMP device 1 that grinds a work-piece, comprises a frame body 41 in which a housing pocket 41a housing a work-piece W is formed, and which is pressed to a grinding pad 5 with the work-piece W. The frame body 41 comprises: a buffer part 46 that is provided so as to surround the housing pocket 41a; and a reinforcement part 47 that includes an abrasion resistance higher than that of the buffer part 46 integrally provided with the buffer part 46, and occupies at least one part of a pressed surface pressed to the grinding pad 5 of the frame body 41.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a CMP apparatus for polishing a workpiece by CMP. [Background technology]

[0002] 2. Description of the Related Art In the field of semiconductor manufacturing, CMP apparatuses are known that planarize semiconductor wafers such as silicon wafers (hereinafter referred to as "workpieces").

[0003] The wafer polishing apparatus described in Patent Document 1 is a polishing apparatus that applies chemical mechanical polishing, or CMP (Chemical Mechanical Polishing) technology. In this wafer polishing apparatus, a wafer W is housed in an annular exchange part 34, and a polishing head 1 polishes the wafer W by pressing it against a polishing cloth 2 using air pressure from an air chamber 61 formed in the gap between the carrier 20 and a rubber sheet 60 whose peripheral edge is held by a retainer ring 30. The reference numerals are those of Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3683149 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the wafer polishing apparatus described above, it is necessary to gently receive the wafer W because, during polishing, the wafer W collides with the inner surface of the replacement part 34 due to dynamic friction with the polishing cloth 2. Furthermore, the replacement part 34 itself is polished as the wafer W is polished, and repeated polishing causes the replacement part 34 to wear and become thinner, which adversely affects the polished shape of the wafer W, and therefore requires periodic replacement.

[0006] For example, if the material of the replacement part 34 is set to be soft, the collision with the wafer W during polishing is cushioned and chipping of the wafer W is suppressed, but the replacement part 34 is easily worn out, which increases the frequency of replacement of the replacement part 34 and shortens the operating time of the apparatus.

[0007] On the other hand, if the replacement part 34 is made of a material with high wear resistance, the frequency of replacement of the replacement part 34 will decrease, but the wafer W will be more likely to be chipped due to collision with the replacement part 34 during polishing.

[0008] Therefore, a technical problem arises that must be solved in order to extend the operating time of the CMP apparatus while suppressing chipping of the workpiece during CMP polishing, and the present invention aims to solve this problem. [Means for solving the problem]

[0009] In order to achieve the above object, the CMP apparatus of the present invention is a CMP apparatus for polishing a workpiece, and includes a frame body in which a storage pocket for storing the workpiece is formed and which is pressed against a polishing pad together with the workpiece, and the frame body includes a buffer section surrounding the storage pocket, and a reinforcing section which is formed integrally with the buffer section, has higher wear resistance than the buffer section, and occupies at least a portion of the pressed surface of the frame body which is pressed against the polishing pad.

[0010] With this configuration, the reinforcing portion, which has higher wear resistance than the buffer portion, occupies at least a portion of the pressed surface of the frame, thereby suppressing wear on the frame, reducing the frequency of frame replacement and extending the operating time of the CMP apparatus. Furthermore, because the buffer portion receives the workpieces that move within the storage pocket during polishing, chipping of the workpieces during polishing can be suppressed. [Effects of the Invention]

[0011] The present invention can extend the operating time of a CMP apparatus and suppress chipping of a workpiece during polishing. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view schematically showing a CMP apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a vertical cross-sectional view schematically showing a main part of the polishing head. [Figure 3] FIG. [Figure 4] Enlarged view of part I in Figure 2. [Figure 5] FIG. 10 is a schematic diagram showing a state in which a workpiece is in contact with a frame during polishing. [Figure 6] 10A and 10B are cross-sectional views showing the main parts of a frame in a CMP apparatus according to a modified example of the present invention, and a schematic view showing a state in which a workpiece is in contact with the frame during polishing. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described below with reference to the drawings. When referring to the number, numerical value, amount, range, etc. of components, unless otherwise specified or when the number is clearly limited to a specific number in principle, the number is not limited to the specific number, and may be greater than or less than the specific number.

[0014] Furthermore, when referring to the shape or positional relationship of components, etc., it includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or when it is clearly considered otherwise in principle.

[0015] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional proportions of the components may not be the same as in reality. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0016] 1 is a perspective view schematically showing a CMP apparatus 1 according to one embodiment of the present invention. The CMP apparatus 1 is used to flatten and polish one surface of a workpiece W. The CMP apparatus 1 includes a platen 2 and a polishing head 10.

[0017] The platen 2 is formed in a disk shape and is connected to a rotary shaft 3 disposed below the platen 2. The rotary shaft 3 is rotated by the drive of a motor 4, causing the platen 2 to rotate in the direction of arrow D1 in Fig. 1. A polishing pad 5 is attached to the upper surface of the platen 2, and CMP slurry, which is a mixture of abrasives and chemicals, is supplied onto the polishing pad 5 from a nozzle (not shown).

[0018] The polishing head 10 is formed in a disk shape with a smaller diameter than the platen 2, and is connected to a rotating shaft 10a disposed above the polishing head 10. The rotating shaft 10a is rotated by a motor (not shown), causing the polishing head 10 to rotate in the direction of arrow D2 in FIG. 1. The polishing head 10 can be raised and lowered in the vertical direction V by an elevator (not shown). When polishing a workpiece W, the polishing head 10 descends and presses the workpiece W against the polishing pad 5. The workpiece W to be polished by the polishing head 10 is transferred by a work transfer mechanism (not shown).

[0019] The operation of the CMP apparatus 1 is controlled by a controller (not shown). The controller controls each of the components that make up the CMP apparatus 1. The controller is, for example, a computer, and is composed of a CPU, memory, etc. The functions of the controller may be realized by control using software, or may be realized by something that operates using hardware.

[0020] Next, the configuration of the polishing head 10 will be described with reference to Figures 2, 3, and 4. As shown in Figure 2, the polishing head 10 includes a head main body 20, a carrier 30, a retaining ring 40, a membrane film 50, and a backing film 60.

[0021] The head body 20 is connected to the rotary shaft 10a and rotates together with the rotary shaft 10a. The head body 20 is connected to a carrier 30 disposed below the head body 20 via a rotating part 21, and the head body 20 and the carrier 30 rotate in unison.

[0022] A carrier pressing means 31 is provided between the head main body 20 and the carrier 30. The carrier pressing means 31 is an air bag or the like that is inflated by air supplied from an air supply source (not shown). The pressure of the air supplied from the air supply source is adjusted by a regulator (not shown). The carrier pressing means 31 presses the workpiece W against the polishing pad 5 via the carrier 30 in accordance with the pressure of the supplied air.

[0023] The carrier 30 is provided with air lines 32 arranged at equal intervals around the periphery of the carrier 30. The lower ends of the air lines 32 open into an air chamber A formed between the underside 30a of the carrier 30 and the membrane film 50. The air lines 32 are connected to an air supply source serving as an air supply means (not shown), and air is introduced into the air chamber A via the air lines 32. The pressure of the air supplied to the air lines 32 is adjusted by a regulator (not shown). The air supplied from the air lines 32 to the air chamber A forms an air pressure layer in the air chamber A that pushes back the pressure transmitted to the carrier 30 by the carrier pressing means 31, and by releasing the excess pressure to the atmosphere, the workpiece W can be pressed with a uniform pressure distribution.

[0024] A plurality of elastic pressing members (not shown) are provided on the lower surface 30a of the carrier 30 and are arranged coaxially. The plurality of pressing members are formed in annular shapes with different diameters. The elastic pressing members are fixed to the lower surface 30a of the carrier 30 by bolts via brackets (not shown). The elastic pressing members are arranged coaxially with the rotation shaft 10a of the polishing head 10 and define an air chamber A.

[0025] The retainer ring 40 is disposed so as to surround the periphery of the carrier 30. The retainer ring 40 includes a frame body 41 on the upper surface of which a membrane film 50 and a backing film 60 are provided.

[0026] The frame 41 is formed in an annular shape and has a storage pocket 41a in the center for storing the workpiece W. The frame 41 is attached to a retainer pressing member 43 via a snap ring 42. A retainer pressing means 44 is provided between the head main body 20 and the retainer pressing member 43. Reference numeral 45 denotes a cover that covers the top of the snap ring 42.

[0027] The retainer pressing means 44 is an air bag or the like that is inflated by air supplied from an air supply source (not shown). The pressure of the air supplied from the air supply source is adjusted by a regulator (not shown). The retainer pressing means 44 presses the retainer ring 40 against the polishing pad 5 via the retainer pressing means 44 in accordance with the pressure of the supplied air.

[0028] The membrane film 50 is made of a resin such as tetrafluoroethylene perfluoroalkoxyvinyl ether copolymer (PFA) or polyethylene terephthalate (PET). The membrane film 50 is bonded to the upper surface of the backing film 60, and when compressed air is introduced into the air chamber A, the membrane film 50 is elastically deformed toward the inside of the storage pocket 41a by the air pressure.

[0029] The backing film 60 is, for example, a suede film. The backing film 60 is attached to the frame body 41 so as to cover the storage pocket 41a. When compressed air is introduced into the air chamber A, the backing film 60 elastically deforms in accordance with the elastic deformation of the membrane film 50, thereby pressurizing the workpiece W.

[0030] As shown in FIG. 4, the frame 41 includes a buffer portion 46 and a reinforcing portion 47.

[0031] The buffer portion 46 is made of a resin such as glass epoxy, nylon (polyamide), polyether ether ketone (PEEK), or polyphenylene sulfide (PPS).

[0032] The reinforcing portion 47 is made of a material that exhibits higher abrasion resistance than the buffer portion 46, such as carbon fiber reinforced plastic (CFRP). CFRP exhibits abrasion resistance that is approximately 20 times that of glass epoxy. Furthermore, because CFRP exhibits higher rigidity than glass epoxy, it is suitable for maintaining the shape of the buffer portion 46 during CMP polishing.

[0033] The buffer portion 46 is formed in a generally annular shape in a plan view so as to surround the storage pocket 41a formed in the center. The buffer portion 46 is exposed to the storage pocket 41a. The buffer portion 46 is layered on the reinforcing portion 47.

[0034] Similar to the buffering portion 46, the reinforcing portion 47 is formed in a generally annular shape in plan view so as to surround the storage pocket 41a formed in the center. The reinforcing portion 47 covers the entire lower surface 46a of the buffering portion 46, in other words, the lower surface 47a of the reinforcing portion 47 occupies the entire surface to be pressed by the polishing pad 5 of the frame 41. The lower surface 46a of the buffering portion 46 and the upper surface 47b of the reinforcing portion 47 are integrated by thermocompression bonding, concave-convex engagement, or the like.

[0035] The thicknesses of the buffer portion 46 and the reinforcing portion 47 are set according to the thickness of the workpiece W so that the buffer portion 46 can receive the side surface of the workpiece W. For example, if the thickness of the workpiece W is 200 μm, the thickness of the buffer portion 46 can be set to 250 μm and the thickness of the reinforcing portion 47 can be set to 50 μm. This ensures a gap between the reinforcing portion 47 and the curved outer peripheral surface of the workpiece W, even when the workpiece W moves within the storage pocket 41a, preventing the reinforcing portion 47 from coming into contact with the workpiece W. The frame 41 is replaced when it has worn down by a predetermined margin (for example, 30 μm).

[0036] Since the buffer portion 46 is exposed to the storage pocket 41a, as shown in FIG. 5, even if the workpiece W moves within the storage pocket 41a due to dynamic friction with the polishing pad 5 during CMP polishing and collides with the buffer portion 46, the buffer portion 46 is configured to gently receive the workpiece W.

[0037] Furthermore, since the reinforcing portion 47 covers the entire lower surface 46a of the buffer portion 46, even if the frame body 41 is pressed against the polishing pad 5 with a pressing force corresponding to the air pressure, as shown in Figure 5, the reinforcing portion 47 is interposed between the buffer portion 46 and the polishing pad 5, preventing the buffer portion 46 from wearing out due to dynamic friction.

[0038] As shown in FIG. 4 , the frame 41 further includes a warpage suppression section 48. Like the buffer section 46 and the reinforcing section 47, the warpage suppression section 48 is formed in a generally annular shape in plan view, surrounding the centrally formed storage pocket 41a. The warpage suppression section 48 is layered on the buffer section 46 and covers the upper surface 46b of the buffer section 46. The upper surface 46b of the buffer section 46 and the lower surface 48a of the warpage suppression section 48 are integrated by thermocompression bonding, concave-convex engagement, or the like. The warpage suppression section 48 is made of a material exhibiting higher rigidity than the buffer section 46, such as CFRP. Furthermore, if the same material as the reinforcing section 47 is used for the warpage suppression section 48, it is preferable that the thickness of the warpage suppression section 48 be set to be generally the same as that of the reinforcing section 47. The shape, material, thickness, and the like of the warpage suppression section 48 may be appropriately adjusted as long as they are capable of suppressing warpage of the buffer section 46 during CMP polishing.

[0039] In this way, the CMP apparatus 1 of this embodiment is a CMP apparatus 1 for polishing a workpiece, and is provided with a frame body 41 in which a storage pocket 41a for storing the workpiece W is formed and which is pressed against the polishing pad 5 together with the workpiece W, and the frame body 41 is configured to include a buffer section 46 surrounding the storage pocket 41a, and a reinforcing section 47 which is formed integrally with the buffer section 46, has higher wear resistance than the buffer section 46, and occupies at least a portion of the pressed surface of the frame body 41 that is pressed against the polishing pad 5.

[0040] With this configuration, the reinforcing portion 47, which has higher wear resistance than the buffer portion 46, is pressed against the polishing pad 5 instead of the buffer portion 46, thereby suppressing wear on the frame body 41 and reducing the frequency of replacing the frame body 41, thereby extending the operating time of the CMP apparatus 1. Furthermore, since the buffer portion 46 receives the workpiece W that moves within the storage pocket 41a during polishing, chipping of the workpiece W during polishing can be suppressed.

[0041] Furthermore, the CMP apparatus 1 according to this embodiment is configured so that the reinforcing portion 47 covers the lower surface 46a of the buffer portion 46.

[0042] With this configuration, the reinforcing portion 47 is interposed between the polishing pad 5 and the buffer portion 46, which suppresses wear of the buffer portion 46 and further reduces the frequency of replacement of the frame 41.

[0043] The CMP apparatus 1 according to this embodiment further includes a warpage suppressing section 48 that covers the upper surface 46b of the buffer section 46, has higher rigidity than the buffer section 46, and suppresses the buffer section 46 from warping.

[0044] With this configuration, the buffer portion 46 is sandwiched between the reinforcing portion 47 and the warp suppressing portion 48, which exhibit high rigidity, and thus the soft buffer portion 46 is prevented from warping during polishing.

[0045] Next, a modified example of this embodiment will be described with reference to Fig. 6. This modified example differs from the above-described embodiment in the configuration of the frame 41. The configuration other than that described below is the same as that of the above-described embodiment.

[0046] In the CMP apparatus 1 according to this modification, as shown in FIG. 6(a), the buffer portion 46 and the reinforcing portion 47 are each formed in a substantially annular shape that is concentric with the receiving pocket 41a as the center.

[0047] The buffer portion 46 is formed in a generally annular shape in plan view so as to surround the storage pocket 41a formed in the center thereof. The buffer portion 46 is provided so as to be exposed to the storage pocket 41a.

[0048] The reinforcing portion 47 is provided on the outer periphery of the buffer portion 46. An outer periphery surface 46c of the buffer portion 46 and an inner periphery surface 47c of the reinforcing portion 47 are integrated by thermocompression bonding, concave-convex engagement, etc. A lower surface 47a of the reinforcing portion 47 occupies a part of the outer periphery of the pressed surface of the frame 41 that is pressed against the polishing pad 5.

[0049] The thicknesses of the buffer portion 46 and the reinforcing portion 47 are set to be approximately the same thickness and are set according to the thickness of the workpiece W so that the buffer portion 46 supports the side surface of the workpiece W. For example, when polishing a workpiece W having a thickness of 200 μm, the thicknesses of the buffer portion 46 and the reinforcing portion 47 are each set to 350 μm.

[0050] Since the buffer portion 46 is exposed to the storage pocket 41a, as shown in Figure 6(b), even if the workpiece W moves within the storage pocket 41a due to dynamic friction with the polishing pad 5 and collides with the buffer portion 46 due to a pressing force corresponding to the air pressure, the buffer portion 46 is configured to gently receive the workpiece W.

[0051] In addition, the lower surface 47a of the reinforcing portion 47 occupies a portion of the outer circumferential side of the pressed surface of the frame body 41 that is pressed against the polishing pad 5, so that when the frame body 41 is pressed against the polishing pad 5 during CMP polishing, the lower surface 46a of the buffer portion 46 and the lower surface 47a of the reinforcing portion 47 each come into contact with the polishing pad 5.

[0052] In this way, the CMP apparatus 1 according to this modification is configured such that the buffer portion 46 is disposed on the inner circumferential side of the reinforcing portion 47 and is capable of coming into contact with the polishing pad 5.

[0053] With this configuration, the reinforcement portion 47 occupies a portion of the pressed surface of the frame body 41 that is pressed by the polishing pad 5, thereby suppressing wear of the frame body 41 and reducing the frequency of replacement of the frame body 41, thereby extending the operating time of the CMP apparatus 1. Furthermore, since the buffer portion 46 receives the workpiece W that moves within the storage pocket 41a during polishing, chipping of the workpiece W during polishing can be suppressed.

[0054] Furthermore, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention, and it goes without saying that the present invention also covers such modifications.

[0055] In other words, the CMP device 1 of the present invention may have any configuration as long as it includes a buffer section 46 that receives the workpiece W moving within the storage pocket 41a during polishing, and a reinforcing section 47 that is integral with the buffer section 46, has higher wear resistance than the buffer section 46, and occupies at least a portion of the pressed surface of the frame body 41. [Explanation of symbols]

[0056] 1:CMP equipment 2: Platen 3: Rotation axis 4: Motor 5: Polishing pad 10: Polishing head 10a: Rotating axis 20: Head body 21: Rotating part 30: Career 30a: Bottom surface 31: Carrier pressing means 32:Airline 34: Replacement part 40: Retainer ring 41:Frame body 41a: Storage pocket 42: Snap ring 43: Retainer pressing member 44: Retainer pressing means 46:Buffer section 46a: (Buffer part) bottom surface 46b: Top surface (of buffer part) 46c: Outer surface 47: Reinforcement 47a: Underside (of reinforcement) 47b: Top surface (of reinforcement) 47c: Inner surface 48: Warp suppression section 48a: Lower surface (of warpage suppression part) 50:Membrane film 60: Backing film A: Air chamber W: Work

Claims

1. A CMP apparatus for polishing a workpiece, a frame body formed with a storage pocket for storing the workpiece and pressed against the polishing pad together with the workpiece; The frame body is a buffer portion provided surrounding the storage pocket; a reinforcing part that is integral with the buffer part, has higher wear resistance than the buffer part, covers the entire lower surface of the buffer part, and occupies at least a part of the pressed surface of the frame that is pressed against the polishing pad; A CMP apparatus comprising:

2. 2. The CMP apparatus according to claim 1, further comprising a warpage suppression section that covers an upper surface of the buffer section, has higher rigidity than the buffer section, and suppresses warpage of the buffer section.

Images