JP4791291B2 - CMP pad - Google Patents

Description

  The present invention relates to a CMP pad for polishing a processing target on a disk surface that is rotatably supported by a platen and to which slurry is supplied, and in particular, an abrasive upper layer, an intermediate layer that blocks the penetration of slurry, and a cushioning lower layer. The present invention relates to a CMP pad that is bonded with an adhesive.

  Currently, a CMP apparatus is used for manufacturing a semiconductor device. The CMP apparatus has a replaceable platen on which a CMP pad is mounted. A semiconductor wafer on which a semiconductor device in a manufacturing process is formed is pressed against a surface of a CMP pad that is rotationally driven together with the platen as a processing target.

  In that case, the semiconductor wafer is reciprocated in the diameter direction of the CMP pad. Further, slurry is supplied to the surface of the CMP pad. Further, the surface of the CMP pad is dressed with a dresser that is also reciprocated in the diametrical direction.

A general CMP pad is formed in a structure in which an abrasive upper layer, an intermediate layer that blocks permeation of slurry, and a lower layer having cushioning properties are joined with an adhesive. Currently, there are various proposals for such a CMP pad (see, for example, Patent Documents 1 to 6).
JP-A-2005-317808 JP-A-2005-054072 JP 2005-159340 A JP 2005-138277 A JP 2003-163191 A JP 2000-306870 A

  The CMP pad as described above is rubbed by the processing object and the dresser in which the rotating disk surface reciprocates in the diameter direction. Therefore, stress acts in the diametrical direction on the surface of the CMP pad from the processing object and the dresser.

  In particular, the dresser is generally small in diameter. For this reason, the CMP pad has a large stroke that moves in the diameter direction. Accordingly, the stress acting on the CMP pad from the dresser is large.

  In the CMP pad, the upper layer and the intermediate layer bonded with an adhesive may peel at the central region due to the stress described above. When this peeling occurs, damage may occur in the central region of the upper layer released from the intermediate layer.

  Patent Documents 4 and 5 disclose a CMP pad in which a concave hole is formed in the center of the lower surface. However, since Patent Document 4 does not disclose the layer structure of the CMP pad, it is difficult to implement.

  Further, in Patent Document 5, in order to make the central region of the CMP pad translucent from the upper surface to the lower surface, a through hole is formed in the central region of the lower layer and the upper layer, and the through hole of the upper layer is filled with a translucent material. A structure is disclosed.

  However, this lacks the mechanical strength of the upper layer. For this reason, in the CMP pad having the above-described structure, when the upper layer is rubbed with a processing object or a dresser, the upper layer is easily broken from the position of the through hole in the central region.

The CMP pad of the present invention is a CMP pad that is rotatably supported by a platen and polishes an object to be processed on a surface to which slurry is supplied, and an upper layer formed as a uniform layer of an abrasive material; The upper layer has an intermediate layer that is bonded to the upper surface with an adhesive to block the penetration of the slurry, and the intermediate layer is bonded to the upper surface with an adhesive and has a cushioning lower layer. It is fixed in the outer peripheral region and not fixed in the central region, and the adhesive that joins the intermediate layer and the lower layer is excluded only in the central region .

  Therefore, in the CMP pad of the present invention, even if stress acts on the upper layer from the processing object or dresser that reciprocates in the diametrical direction, the central region of the upper layer is prevented from peeling from the intermediate layer due to the stress.

  In the CMP pad of the present invention, the intermediate layer and the lower layer are fixed in the outer peripheral region and are not fixed in the central region. For this reason, even if a stress acts on the upper layer from the processing object or dresser that reciprocates in the diametrical direction, the central region of the upper layer can be prevented from peeling from the intermediate layer due to the stress. Therefore, damage to the upper layer due to peeling from the intermediate layer can be prevented.

  A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the CMP pad 100 of the present embodiment includes an upper layer 110 formed as a uniform layer of an abrasive material, and the upper layer 110 is bonded to the upper surface with an adhesive 120 so that the slurry S An intermediate layer 130 that blocks permeation, and a lower layer 150 that has a cushioning property as the intermediate layer 130 is bonded to the upper surface with an adhesive 140.

  In the CMP pad 100 of the present embodiment, only the central region C is removed from the adhesive 140 that joins the intermediate layer 130 and the lower layer 150. For this reason, the intermediate layer 130 and the lower layer 150 are fixed in the outer peripheral region O and are not fixed in the central region C.

  Since the upper layer 110 is formed as a uniform layer as described above, no voids such as recesses and through holes are formed in the central region. Since the lower layer 150 is also formed as a uniform layer, no voids such as recesses and through holes are formed in the central region.

  As shown in FIG. 2, the CMP apparatus 200 of the present embodiment includes a platen 210 to which the CMP pad 100 is attached in a replaceable manner. A semiconductor wafer on which a semiconductor device in the manufacturing process is formed is pressed against the surface of the CMP pad 100 that is rotationally driven together with the platen 210 (not shown).

  More specifically, the semiconductor wafer is held by the holder unit 220. The holder unit 220 reciprocates in the diameter direction of the CMP pad 100 while rotating the semiconductor wafer.

  A dresser 230 is also pressed against the surface of the CMP pad 100 that is rotationally driven together with the platen 210. The dresser 230 is also reciprocated in the diameter direction of the CMP pad 100 while being rotationally driven.

  A dropping device 240 is disposed above the surface of the CMP pad 100 supported by the platen 210. The dropping device 240 supplies the slurry S to the surface of the CMP pad 100.

  The dresser 230 has a smaller diameter than the holder unit 220. For example, the dresser 230 has a smaller diameter than one half of the radius of the CMP pad 100, and the holder unit 220 has a larger diameter than one half of the radius of the CMP pad 100. For this reason, the distance of the reciprocating movement of the CMP pad 100 in the diameter direction is small in the holder unit 220 and large in the dresser 230.

  In the CMP pad 100 of the present embodiment, the central region C where the intermediate layer 130 and the lower layer 150 are not fixed is rubbed by the dresser 230 inside the outer peripheral region of the upper layer 110 for polishing the semiconductor wafer. It is located inside the outer peripheral region of the upper layer 110.

  In the CMP pad 100 of the present embodiment, for example, the upper layer 110 is formed with a layer thickness of 1.17 to 1.37 mm by a thermosetting elastic polyurethane resin having a Shore-D hardness of 52 to 62. The adhesive 120 is formed of an acrylic pressure-sensitive adhesive material with a layer thickness of 45 μm.

  The intermediate layer 130 is formed of PET (Polyethylene Terephthalate) to a layer thickness of 30 μm. The adhesive 140 is made of an acrylic pressure-sensitive adhesive material and has a layer thickness of 45 μm. The lower layer 150 is made of a polyester nonwoven fabric impregnated with a polyurethane resin having an Asker-C hardness of 62 to 70, and has a layer thickness of 1.20 to 1.34 mm.

  The CMP pad 100 is formed with a diameter of 508 mm, for example. Moreover, the diameter of the range which does not grind | polish a semiconductor wafer is 50 mm, for example. The diameter of the central region C where the intermediate layer 130 and the lower layer 150 are not fixed is, for example, 20 mm. The dresser 230 reciprocates from the center of the CMP pad 100 to the outer edge and rubs the entire board surface.

  In the above-described configuration, in the CMP apparatus 200 according to the present embodiment, the CMP pad 100 is replaceably mounted on the surface of the platen 210. Therefore, when the semiconductor wafer is subjected to the CMP process, the semiconductor wafer is loaded into the holder unit 220.

  The semiconductor wafer held by the holder unit 220 is pressed against the surface of the CMP pad 100 that is rotationally driven together with the platen 210. At this time, the semiconductor wafer is also reciprocated in the diameter direction of the CMP pad 100 while being rotationally driven.

  Further, the slurry S is also supplied to the surface of the CMP pad 100. Thus, the CMP process is performed on the surface of the semiconductor wafer by the CMP pad 100. At this time, contamination adheres to the surface of the CMP pad 100.

  However, the surface of the CMP pad 100 polishing the semiconductor wafer as described above is simultaneously dressed by the dresser 230. For this reason, the polishability of the surface of the CMP pad 100 is always kept good.

  The above-described dresser 230 is also reciprocated in the diameter direction of the CMP pad 100 while being rotationally driven. For this reason, even the small-diameter dresser 230 can satisfactorily dress the surface of the large-diameter CMP pad 100.

  However, as described above, the stroke of the dresser 230 that reciprocates in the diameter direction of the CMP pad 100 is large. For this reason, stress that cannot be ignored in the diameter direction acts on the upper layer 110 of the CMP pad 100 from the dresser 230.

  However, in the CMP pad 100 of the present embodiment, the intermediate layer 130 and the lower layer 150 are fixed in the outer peripheral region O and are not fixed in the central region C. For this reason, even if stress acts in the diametrical direction from the dresser 230 as described above, the upper layer 110 and the intermediate layer 130 joined by the adhesive 120 do not peel in the central region C.

  This is considered as follows. When the dresser 230 reciprocates in the diameter direction of the CMP pad 100, stress acts on the upper layer 110 in the diameter direction. At this time, the upper layer 110 is slightly deformed and displaced in the diameter direction where the stress acts.

  At this time, if the intermediate layer 130 does not follow the deformation and displacement generated in the upper layer 110 well, peeling occurs. However, the intermediate layer 130 is not fixed to the lower layer 150 in the central region C. For this reason, the center region C of the intermediate layer 130 can follow the deformation and displacement of the upper layer 110 satisfactorily, and it can be prevented that peeling occurs there.

  Note that the outer peripheral surface of the CMP pad 100 is open. For this reason, even if the intermediate layer 130 is fixed to the lower layer 150 in the outer peripheral region O, it can follow the deformation and displacement of the upper layer 110 satisfactorily. Therefore, peeling does not occur there.

  In addition, the inventor has a CMP pad having a conventional structure in which an upper layer, an intermediate layer, and a lower layer are fixed with an adhesive, and a CMP pad in which the intermediate layer and the lower layer are not fixed in a central region as described above. , And made an experiment (not shown).

  Then, in the CMP pad having the conventional structure, the upper layer and the intermediate layer were separated in the central region. However, it was confirmed that the upper layer and the intermediate layer do not peel in the CMP pad in which the intermediate layer and the lower layer are not fixed in the central region.

  In the CMP pad 100 of the present embodiment, the intermediate layer 130 and the lower layer 150 are fixed in the outer peripheral region O and not fixed in the central region C as described above. For this reason, it is possible to prevent the upper layer 110 and the intermediate layer 130 from separating in the central region C even if the disk surface is rubbed by the dresser 230 moved in the diameter direction.

  In addition, a structure in which the intermediate layer 130 and the lower layer 150 are fixed in the outer peripheral region O and not fixed in the central region C is realized by removing only the central region C from the adhesive 140 that joins the intermediate layer 130 and the lower layer 150. ing.

  For this reason, no special processing is required for the intermediate layer 130 or the lower layer 150. Therefore, a structure having a simple structure and good productivity can be provided as the CMP pad 100. Further, it is not necessary to form a through hole or the like in the intermediate layer 130. For this reason, it is possible to effectively prevent the slurry S from penetrating below the intermediate layer 130.

  Further, the central region C where the intermediate layer 130 and the lower layer 150 are not fixed is located inside the outer peripheral region of the upper layer 110 that polishes the semiconductor wafer. For this reason, the central region C of the intermediate layer 130 is not supported by the lower layer 150, so that the semiconductor wafer does not press well against the upper layer 110.

  In the CMP pad 100 of the present embodiment, the upper layer 110 is formed as a uniform layer of an abrasive material. Therefore, the strength of the upper layer 110 is good, and it is possible to prevent the upper layer 110 from being broken due to the stress acting in the diametrical direction from the dresser 230.

  The present invention is not limited to the present embodiment, and various modifications are allowed without departing from the scope of the present invention. For example, in the above embodiment, the material and dimensions of each part are specifically exemplified. However, the material and dimensions can be variously modified within a range that satisfies the required functions.

  Next, a second embodiment of the present invention will be described below with reference to FIG. In the following description, the same parts as those in the first embodiment described above are denoted by the same names and reference numerals, and detailed description thereof is omitted.

  The CMP pad 300 of this embodiment also includes an upper layer 110, an adhesive 120, an intermediate layer 130, an adhesive 140, and a lower layer 310. Furthermore, in the CMP pad 300 of the present embodiment, not only the central region C is removed from the adhesive 140 that joins the intermediate layer 130 and the lower layer 310, but also the recess 311 is formed in the central region C on the upper surface of the lower layer 310. Is formed. For this reason, the intermediate layer 130 and the lower layer 310 are fixed in the outer peripheral region O and are not fixed in the central region C.

  In the configuration as described above, the CMP pad 300 of the present embodiment also has the intermediate layer 130 and the lower layer 310 fixed in the outer peripheral region O and not fixed in the central region C, like the CMP pad 100 described above. . For this reason, it is possible to prevent the upper layer 110 and the intermediate layer 130 from separating in the central region C even if the disk surface is rubbed by the dresser 230 moved in the diameter direction.

  In the above embodiment, only the central region C is removed from the adhesive 140 that joins the intermediate layer 130 and the lower layer 310, and the recess 311 is formed in the central region C on the upper surface of the lower layer 310. It is illustrated that 130 and the lower layer 310 are not fixed in the central region C.

  However, like the CMP pad 320 illustrated in FIG. 4, the adhesive 321 may be formed on the entire lower surface of the intermediate layer 130, and the recess 311 may be formed on the central region C on the upper surface of the lower layer 310. Also in this case, since the intermediate layer 130 and the lower layer 310 are not fixed in the central region C, it is possible to prevent the upper layer 110 and the intermediate layer 130 from being separated in the central region C.

  Next, a third embodiment of the present invention will be described below with reference to FIG. The CMP pad 400 of this embodiment also includes an upper layer 110, an adhesive 120, an intermediate layer 130, an adhesive 140, and a lower layer 410.

  In the CMP pad 400 of the present embodiment, not only the central region C is removed from the adhesive 140 that joins the intermediate layer 130 and the lower layer 410 but also the through hole 411 in the central region C on the upper surface of the lower layer 410. Is formed. For this reason, the intermediate layer 130 and the lower layer 410 are fixed in the outer peripheral region O and not fixed in the central region C.

  In the configuration as described above, the CMP pad 400 of the present embodiment also has the intermediate layer 130 and the lower layer 410 fixed in the outer peripheral region O and fixed in the central region C, like the CMP pads 100 and 300 described above. Not. For this reason, it is possible to prevent the upper layer 110 and the intermediate layer 130 from separating in the central region C even if the disk surface is rubbed by the dresser 230 moved in the diameter direction.

  In the above embodiment, only the central region C is removed from the adhesive 140 that joins the intermediate layer 130 and the lower layer 410, and the through hole 411 is formed in the central region C on the upper surface of the lower layer 410. It is illustrated that the layer 130 and the lower layer 410 are not fixed in the central region C.

  However, like the CMP pad 420 illustrated in FIG. 6, the adhesive 321 may be formed over the entire lower surface of the intermediate layer 130, and the through hole 411 may be formed in the central region C of the upper surface of the lower layer 410. Also in this case, since the intermediate layer 130 and the lower layer 410 are not fixed in the central region C, it is possible to prevent the upper layer 110 and the intermediate layer 130 from being separated in the central region C.

It is a typical side view which shows the laminated structure of the CMP pad of 1st Embodiment of this invention. It is a schematic diagram which shows the state which CMP-processes the semiconductor wafer which is a process target with the CMP pad with which the CMP apparatus was mounted | worn. It is a typical side view which shows the laminated structure of the CMP pad of 2nd Embodiment. It is a typical side view which shows the modification. It is a typical side view which shows the laminated structure of the CMP pad of 3rd Embodiment. It is a typical side view which shows the modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 CMP pad 110 Upper layer 120 Adhesive 130 Intermediate layer 140 Adhesive 150 Lower layer 200 CMP apparatus 210 Platen 220 Holder unit 230 Dresser 240 Dropping device 300 CMP pad 310 Lower layer 311 Recess 320 CMP pad 321 Adhesive 400 CMP pad 410 Lower layer 411 Through-hole 420 CMP pad C Central region O Outer peripheral region S Slurry

Claims (8)

A CMP (Chemical Mechanical Polishing) pad that polishes an object to be processed on a disk surface that is rotatably supported by a platen and supplied with slurry,
An upper layer formed as a uniform single layer of an abrasive material, an intermediate layer that is bonded to the upper surface with an adhesive and blocks the penetration of the slurry, and the intermediate layer is bonded to the upper surface with an adhesive And a lower layer having cushioning properties,
A CMP pad in which the intermediate layer and the lower layer are fixed in an outer peripheral region but not fixed in a central region, and the adhesive that joins the intermediate layer and the lower layer is excluded only in the central region .   The CMP pad according to claim 1, wherein the intermediate layer and the lower layer are not fixed in the central region inside the outer peripheral region of the upper layer for polishing the processing target.   The CMP pad according to claim 1, wherein the intermediate layer and the lower layer are not fixed in the central region inside the outer peripheral region of the upper layer that is abraded by a dresser. The CMP pad according to claim 1 , wherein the lower layer is formed as a uniform layer. The CMP pad according to claim 1 , wherein no gap is formed in the central region of the lower layer. The CMP pad according to any one of claims 1 to 3 , wherein a recess is formed in the central region of the upper surface of the lower layer. The CMP pad according to any one of claims 1 to 3 , wherein a through hole is formed in the central region of the lower layer from the upper surface to the lower surface. CMP pad according to any one of claims 1 to 7 no gap is formed in the center region of the upper layer.

Images