KR101495141B1 - Polishing pad for eddy current end-point detection - Google Patents

Abstract

A polishing pad for polishing a semiconductor substrate used for detecting an eddy current end point is described. A method of manufacturing a polishing pad for polishing a semiconductor substrate used for eddy current detection is also described.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polishing pad,

An embodiment of the present invention relates to the field of chemical mechanical polishing (CMP) technology, and more particularly to a polishing pad for eddy current endpoint detection.

Chemical mechanical planarization or chemical mechanical polishing, commonly abbreviated as CMP, is a technique used to planarize semiconductor wafers or other substrates in semiconductor manufacturing.

This process generally uses abrasive and corrosive chemical slurries (commonly referred to as colloids) combined with polishing pads and retaining rings that have a larger diameter than the wafer. The polishing pad and wafer are pressed together by the dynamic polishing head and held in place by the plastic retaining ring. The dynamic polishing head is rotated during polishing. This approach helps remove material and makes it easier to planarize irregular topography, making the wafer flat or flat. This may be necessary to set up the wafer for the formation of additional circuit elements. For example, this may be necessary to make the entire surface within the depth of field of the photolithography system, or to selectively remove material based on that location. Typical depth requirements are lowered to Angstrong for the latest sub-50 nm technology nodes.

The material removal process is not as simple as abrasive scraping as sandpaper on wood. The chemicals in the slurry also act to react with the material to be removed and / or to weaken the material to be removed. The abrasive accelerates this weakening process and the polishing pad helps to wipe out the reacted material from the surface.

The problem with CMP is to determine whether the polishing process is complete, e.g. whether the substrate layer has been flattened to the desired flatness or thickness, or when the target amount of material has been removed. Excessive polishing of the conductive layer or film results in increased circuit resistance. In contrast, poor polishing of the conductive layer or film can cause electrical shorts. Changes in the initial thickness of the substrate layer, the slurry composition, the state of the polishing pad, the relative speed between the polishing pad and the substrate, and the load on the substrate cause a change in the material removal rate. These changes cause a change in the time required to reach the polishing end point. Thus, the polishing end point can often not be simply determined as a function of polishing time.

One way to determine the polishing end point is to monitor the polishing of the metal layer on the substrate in situ, for example with an optical and electrical sensor. One technique to monitor is to induce eddy currents in a metal layer with a magnetic field to detect changes in magnetic flux as the metal layer is removed. The magnetic flux generated by the eddy current is in the opposite direction of the exitation flux line. This flux is proportional to the eddy current, the eddy current is proportional to the resistance of the metal layer, and the resistance of the metal layer is proportional to the thickness of the metal layer. Thus, a change in the thickness of the metal layer causes a change in the magnetic flux generated by the eddy current. This change in magnetic flux causes a change in current in the primary coil, which can be measured as a change in impedance. As a result, changes in the coil impedance reflect changes in the metal layer thickness. However, the polishing pad will have to be modified to accommodate eddy current measurements during polishing of the real time metal layer on the substrate.

Thus, in addition to improvements in slurry technology, polishing pads play an important role in increasingly complex CMP operations. However, further improvements in the development of CMP pad technology are required.

Embodiments of the present invention include a polishing pad for eddy current endpoint detection.

In one embodiment, the polishing pad for polishing the semiconductor substrate comprises a mold-shaped uniform polishing body. The mold-shaped uniform polishing body has a polishing surface and a back surface. The polishing pad also includes an end-point detection zone disposed in the mold-shaped uniform polishing body and covalently bonded to the mold-shaped uniform polishing body. The end point detection zone is made of a material different from the mold-shaped uniform polish body, and at least a part of the end point detection zone is recessed with respect to the back surface of the mold-shaped uniform polish body.

In another embodiment, a method of manufacturing a polishing pad for polishing a semiconductor substrate includes forming a mold-shaped uniform polishing body. The mold-shaped uniform polishing body has a polishing surface and a back surface. The method also includes the step of forming an endpoint detection zone which is disposed in the mold-shaped uniform polishing body and is covalently bonded to the mold-shaped uniform polishing body. The end point detection zone is made of a material different from the mold-shaped uniform polish body, and at least a part of the end point detection zone is recessed with respect to the back surface of the mold-shaped uniform polish body.

In one embodiment, the polishing pad for polishing a semiconductor substrate includes a mold-shaped uniform polishing body having a polishing surface and a back surface. The pattern of the groove is disposed on the polishing surface, and the pattern of the groove has the bottom depth portion. The polishing pad also includes an end-point detection zone formed in the mold-shaped uniform polishing body. The endpoint detection zone has a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface. At least a portion of the first surface is coplanar with the bottom depth portion in the pattern of the grooves, thereby breaking the pattern of grooves. The second surface is recessed into a uniform polishing body which is molded with respect to the back surface.

In another embodiment, a method of manufacturing a polishing pad includes forming a polishing pad precursor mixture in a forming mold. The cover of the forming mold is located in the polishing pad precursor mixture. The cover has a pattern of grooves disposed thereon, and the pattern of grooves has a cut-off area. The polishing pad precursor mixture is cured to provide a mold-shaped uniform polishing body having a polishing surface and a back surface. The pattern of grooves in the cover is disposed on the polishing surface, and the pattern of the grooves has a bottom depth portion. The end point detection zone is provided in a mold-shaped uniform polishing body, and the end point detection zone has a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface. At least a portion of the first surface is coplanar with the bottom depth portion in the pattern of grooves and includes a cut-off region in the pattern of grooves. On the other hand, the second surface is recessed into a uniform polishing body which is molded with respect to the back surface.

In one embodiment, a method of manufacturing a polishing pad for polishing a semiconductor substrate includes forming a polishing pad having a mold-shaped uniform polishing body having a polishing surface and a back surface by a molding process. The pattern of the groove is disposed on the polishing surface, and the pattern of the groove has the bottom depth portion. The polishing pad also includes an end-point detection zone formed in the mold-shaped uniform polishing body. The endpoint detection zone has a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface. At least a portion of the first surface is coplanar with the bottom depth portion in the pattern of grooves and breaks the pattern of grooves. The second surface is recessed into a uniform polishing body which is molded with respect to the back surface.

In one embodiment, a method of making a polishing pad comprises forming a partially cured endpoint detection zone precursor in a first shaping mold. The partially cured endpoint detection zone precursor is positioned on the receiving area at the lid of the second molding die. The polishing pad precursor mixture is provided in a second shaping mold. Approaching the base of the cover and the second shaping mold, the partially cured endpoint detection zone precursor is moved into the polishing pad precursor mixture. The polishing pad precursor mixture and the partially cured endpoint detection zone precursor are heated to provide a mold-shaped uniform polishing body that is covalently bonded to the cured endpoint detection zone precursor, and the mold-shaped uniform polishing body has a polishing surface and a back surface I have. The cured endpoint detection zone precursor is recessed against the backside of the mold-shaped uniform polishing body to provide an end-point detection zone that is disposed in the mold-shaped uniform polishing body and is covalently bonded to the mold-shaped uniform polishing body.

In another embodiment, a method for manufacturing a polishing pad includes positioning a support structure within a first shaping mold. The detection zone precursor mixture is provided on the support structure in a first shaping mold. The partially cured endpoint detection zone precursor is formed by heating the detection zone precursor mixture in the first shaping mold and the partially cured endpoint detection zone precursor is bonded to the support structure. The support structure and the partially cured endpoint detection zone precursor are placed on the receiving area of the recessed lid in the second forming mold by engaging the support structure in the receiving space of the recessed lid. The polishing pad precursor mixture is provided in a second shaping mold. Approaching the base of the cover and the second shaping mold, the partially cured endpoint detection zone precursor is moved into the polishing pad precursor mixture. The polishing pad precursor mixture and the partially cured endpoint detection precursor are heated to provide a mold-shaped uniform polishing body that is covalently bonded to the cured endpoint detection zone precursor, and the mold-shaped polishing body has a polishing surface and a back surface, The endpoint detection zone is coupled to the support structure. The support structure is removed from the endpoint detection zone.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing pad for polishing a semiconductor substrate used for detecting an eddy current end point and a method for manufacturing a polishing pad for polishing a semiconductor substrate used for eddy current detection, And whether or not the substrate layer has been flattened to the target flatness or thickness, as well as the end point of the polishing can be determined.

1A is a cross-sectional view of a polishing pad suitable for detecting an eddy current end time point and for polishing a semiconductor substrate according to an embodiment of the present invention.
FIG. 1B is a top view of the polishing pad of FIG. 1A according to one embodiment of the present invention.
2A is a cross-sectional view of a polishing pad suitable for detecting an eddy current end time point and polishing a semiconductor substrate according to an embodiment of the present invention.
Figure 2B is a top view of the polishing pad of Figure 2A in accordance with one embodiment of the present invention.
FIG. 3A is a cross-sectional view of a polishing pad suitable for detecting an eddy current end time point and for polishing a semiconductor substrate according to an embodiment of the present invention. FIG.
FIG. 3B is a cross-sectional view of a polishing pad suitable for detecting an eddy current end time point and for polishing a semiconductor substrate according to an embodiment of the present invention. FIG.
4A is a cross-sectional view of a polishing pad suitable for detecting an eddy current end time point and polishing a semiconductor substrate according to an embodiment of the present invention.
4B is a top view of the polishing pad of FIG. 4A according to one embodiment of the present invention.
FIG. 5A is a cross-sectional view of a polishing pad suitable for detecting an eddy current end time point and polishing a semiconductor substrate according to an embodiment of the present invention. FIG.
Figure 5B is a top view of the polishing pad of Figure 5A according to one embodiment of the present invention.
6A to 6T are cross-sectional views of a manufacturing process used in the production of a polishing pad according to an embodiment of the present invention.
7A to 7D are cross-sectional views of a manufacturing process used in the production of a polishing pad according to an embodiment of the present invention.
8A to 8F are cross-sectional views of a manufacturing process used in the production of a polishing pad according to an embodiment of the present invention.
9A to 9F are cross-sectional views of a manufacturing process used in the production of a polishing pad according to an embodiment of the present invention.
10 is an isometric view of an abrasive device that can be used with a polishing pad for eddy current endpoint detection according to an embodiment of the present invention.
11 is a cross-sectional view of a polishing apparatus having an abrasive pad usable with an eddy current endpoint detection system and a vortex endpoint detection system in accordance with an embodiment of the present invention.

A polishing pad for polishing a semiconductor substrate using eddy current endpoint detection is described herein. In the following description, numerous specific details are set forth such as specific polishing pad configurations and designs, for example, to provide a thorough understanding of embodiments of the present invention. It will be apparent to those of ordinary skill in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, known processing techniques, such as, for example, the combination of a polishing pad and a slurry to perform CMP of a semiconductor substrate, will not be described in detail in order not to unnecessarily obscure the present invention. Moreover, the various embodiments shown in the drawings are for illustrative purposes only and are not shown in scale.

The polishing pad may be configured to include a region designed to accommodate an eddy current detection probe integrated within a platen of a chemical mechanical polishing apparatus. For example, in one embodiment of the present invention, a separate material zone is contained within the polishing pad during the molding of the polishing pad. A separate material zone has a shape and size to accommodate an eddy current probe protruding from the platen. Moreover, this area is made at least somewhat transparent, allowing the polishing pad to align easily on the platen, including the eddy current probe. In another embodiment of the present invention, the polishing pad is a mold-shaped uniform polishing body having a recess formed in the back region of the polishing body as a whole. The recess may also have a shape and size to accommodate an eddy current probe protruding from the platen. In some embodiments, a single recess is sized to accommodate all eddy current detection sites protruding above the platen. In addition, when the mold-shaped uniform polishing body is opaque, the pattern may be formed on the polishing surface of the polishing pad, which indicates the position of the recess on the back surface of the polishing pad or is a key to that position have. This key can be used to easily align the polishing pad on the platen including the eddy current probe.

According to one embodiment of the present invention, a polishing pad for polishing a semiconductor substrate is provided to allow a device such as a sensor to extend over the platen of the GMP tool. For example, in one embodiment, the polishing pad facilitates use in an abrasive tool suitable for an eddy current endpoint detection system, including design features, and use in a CMP process utilizing eddy current endpoint detection. The polishing pad design structure generally allows the eddy current sensor of the CMP tool to stand up the plane of the CMP tool platen and extends to the back of the polishing pad while the polishing process is in progress. In one embodiment, the design structure allows the above motion to occur without affecting the overall polishing performance of the polishing pad. The design structure also allows the polishing pad to be positioned in the correct orientation on the platen, so that the eddy current sensor can stand upright on the plane of the platen without interference.

In one embodiment, the design structure includes recesses on the back side of the polishing pad positioned with an appropriate size and shape to align with the eddy current sensor. In one embodiment, another design structure includes means for visually orienting the polishing pad over the platen, aligning it with the position of the sensor, e.g., an eddy current sensor. In some embodiments, the polishing pad has a transparent portion. In another embodiment, the polishing pad is completely opaque, but includes a visible signal or key that indicates the position of the corresponding backplane recess, such as a disconnection pattern on the polishing surface.

In one aspect of the present invention, the polishing pad for use in eddy current detection includes an endpoint detection zone made of a material different from the rest of the polishing pad. For example, Figure 1A is a cross-sectional view of a polishing pad suitable for detecting an eddy current endpoint in accordance with one embodiment of the present invention. 1B is a top view of the polishing pad of FIG. 1A according to one embodiment of the present invention.

Referring to FIGS. 1A and 1B, a polishing pad 100 includes a mold-shaped uniform polishing body 102. The mold-shaped uniform polishing body 102 has a polishing surface 104 and a back surface 106 (note that the back surface 106 is shown only in FIG. 1A). The polishing surface 104 includes a plurality of grooves 150 as shown in FIG. The end point detection zone 108 is composed of a material portion 110 different from the mold-shaped uniform polishing body 102. The material portion 110 has a portion 112 covalently bonded to the material of the mold-shaped uniform polishing body 102.

In one embodiment, the endpoint detection zone 108 is thinner than most polishing pads, even if there are grooves or no grooves, as shown in FIG. 1A. For example, in one embodiment, the thickness T3 of the material portion 110 in the endpoint detection zone 108 is thinner than the thickness T1 of the mold-shaped uniform polishing body 102. Particularly, the thickness T3 is thinner than a part of the thickness T2 of the mold-shaped uniform polishing body 102 excluding the grooves 150 on the polishing surface 104. [ In a particular embodiment, the thickness T1 is the thinnest portion of the polishing pad 100.

Referring to FIG. 1A, at least a portion of the material portion 110 in the endpoint detection zone 108 is recessed with respect to the backside 106 of the mold-shaped uniform polishing body 102. For example, in one embodiment, the material portion 110 of the endpoint detection zone 108 is completely recessed against the backside 106 of the mold-shaped polishing body 102. In particular, the material portion 110 of the endpoint detection zone 108 has a first surface 114 and a second surface 116. The second surface 116 is recessed by D relative to the back surface 106. In one embodiment, the second surface 116 is recessed by D and is sufficient to accommodate an eddy current probe protruding from the platen of the chemical mechanical polishing apparatus. In a particular embodiment, the recess depth D is on the order of about 70 mil (1 / 1,000 in) below the surface 106.

Referring to FIG. 1B in one embodiment, the polishing surface 104 of the mold-shaped uniform polishing body 102 has a pattern of grooves disposed therein, that is, a pattern formed by the grooves 150 shown in FIG. 1A. In one embodiment, the pattern of grooves includes a plurality of concentric polygons 118 along a plurality of radial lines 120 as shown in FIG. 1B.

In one embodiment, the term "covalently bonded" refers to the fact that an atom from the material portion 110 of the endpoint detection zone 108 is cross-linked or electrons with atoms from a uniformly polished body 102, Refers to a configuration that achieves chemical bonding. This covalent bond is distinguished from the electrostatic interaction that can occur when a portion of the polishing pad is cut away and replaced with an insertion area such as a window insert. Covalent bonds are also distinguished from mechanical bonds such as, for example, bonding by screws, nails, glue or other adhesives. As described in detail below, covalent bonding can be accomplished by curing the polishing body precursor together with the endpoint detection zone precursor already disposed therein, as opposed to the polishing body and subsequent additional inserts being formed separately.

In another embodiment, the material portion of the endpoint detection zone is not completely recessed against the backside of the mold-shaped uniform polishing body. For example, FIG. 2A is a cross-sectional view of another polishing body according to another embodiment of the present invention. Figure 2B is a top view of the polishing pad of Figure 2A according to one embodiment of the present invention.

Referring to FIGS. 2A and 2B, the polishing pad 200 includes a mold-shaped uniform polishing body 202. The mold-shaped uniform polishing body 202 has a polishing surface 204 and a back surface 206 (note that the back surface 206 is shown only in FIG. 2A). The end point detection zone 208 is disposed in the mold-shaped uniform polishing body 202. The end point detection zone 208 is composed of a material portion 210 that is different from the mold-shaped uniform polishing body 202. The material portion 210 has a portion 212 that is covalently bonded to the material of the mold-shaped uniform polishing body 202.

In one embodiment, only a portion of the material portion 210 of the endpoint detection zone 208 is recessed relative to the backside 206 of the mold-shaped uniform polishing body 202. For example, the material portion 210 of the endpoint detection zone 208 has a first surface 214, a second surface 216, and a third surface 218. The second surface includes only the inner portion of the endpoint detection zone 208 and is formed by the back surface 206 of the mold-shaped uniform polishing member 202 and the surface 206 of the third surface 218 of the end point detection zone 208 . The sidewall 220 of the endpoint detection zone 208 remains along the contact surface 222 where the endpoint detection zone 208 and the mold-shaped uniform polishing body 202 make contact.

In one embodiment, the covalent bond between the endpoint detection zone 208 and the mold-shaped uniform polishing body 202 is achieved to a greater extent by holding the sidewall 220 to maintain the integrity of the polishing pad 200 ). In one embodiment, the second surface 216 is recessed by D to fully accommodate an eddy current probe protruding from the platen of the chemical mechanical polishing apparatus. In a particular embodiment, the recess depth D is on the order of about 70 mil (1 / 1,000 in) below the surface 206.

1a, 1b, 2a and 2b according to an embodiment of the present invention, the endpoint detection zone (e.g., zone 108 or 208) is a local area transparency (LAT) zone. In one embodiment, the mold-shaped uniform polishing body is opaque, while the LAT zone is not opaque. In one embodiment, the mold-shaped uniform polishing body is opaque, including at least partly an inorganic material in the material used in manufacturing as described below. In this embodiment, the LAT zone is fabricated by excluding inorganic materials and is generally, if not completely, transparent to, for example, visible, ultraviolet, infrared or combinations thereof. In a specific embodiment, the inorganic material contained in the mold-shaped uniform polishing body is an opaque lubricant, which does not contain any inorganic materials and is essentially free of opacifying lubricants.

In one embodiment, the LAT zone is substantially transparent (ideally completely transparent) such that light is transmitted through the polishing pad, e.g., for positioning the polishing pad on the platen or for endpoint detection. However, even if the LAT zone can not be made completely transparent or need to be manufactured, it may still be effective in locating the polishing pad on the platen or in transferring light for end point detection. For example, in one embodiment, the LAT zone is less than 80% of the incident light in the 700-710 nm range, but is still well suited to act as a window inside the polishing pad. In one embodiment, the LAT zone described above is impervious to the slurry used in chemical mechanical polishing operations.

1B and 2B in one embodiment, the endpoint detection zones 108 and 208 are each a LAT zone and are transparent in a plan view. In one embodiment, this visible transparency aids in mounting the polishing pad on the platen on which the eddy current detection probe is mounted. In Fig. 2b, the sidewall 220 can be seen in this perspective view as shown in a rectangular shape shown in dashed lines.

However, in other embodiments, the material of the endpoint detection zone is opaque and thus does not serve to provide a local transparent subarea. For example, Figures 3A and 3B are cross-sectional views of another polishing pad according to another embodiment of the present invention.

Referring to FIGS. 3A and 3B, the polishing pad 300 (or 300 ') includes a mold-shaped uniform polishing body 302. The mold-shaped uniform polishing body 302 has a polishing surface 304 and a back surface 306. The end point detection zone 308 (or 308 ') is disposed in the mold-shaped uniform polishing body 302. The end point detection zone 308 (or 308 ') consists of a non-transparent material portion 310 that is different from the mold-shaped uniform polish body 302. The material portion 310 has a portion 312 covalently bonded to the material of the mold-shaped uniform polishing body 302.

3A, the material portion 310 of the endpoint detection zone 308 is completely recessed against the backside 306 of the mold-shaped uniform polishing body 302. In this embodiment, 3B, only a portion of the material portion of the endpoint detection zone 308 'is recessed relative to the backside 306 of the mold-shaped uniform polishing body 302 and the side walls 320 are left Leave. In one embodiment, the end point detection zone 308 (or 308 ') is an opaque zone having a hardness different from the hardness of the mold-shaped uniform polishing body 302. In certain embodiments, the hardness of the endpoint detection zone 308 (or 308 ') is greater than the hardness of the mold-shaped uniform polishing body 302. However, in an alternative embodiment, the endpoint detection zone 308 (or 308 ') is less than the hardness of the mold-shaped uniform polishing body 302. In one embodiment, the endpoint detection zone 308 (or 308 ') is immersive to the slurry used in chemical mechanical polishing operations.

Although the end-point detection zone 308 (or 308 ') consists of the opaque material portion 310, this zone allows the polishing pad 300 or 300' to be mounted visibly on the platen on which the eddy current probe is mounted, respectively Can still be used. For example, in one embodiment, the absence of a groove-shaped pattern on the first surface 304 of the end-point detection zone 308 (or 308 ') is determined by the position of the end-point detection zone 308 (or 308' Or a key for that position.

In another aspect of the present invention, a polishing pad for use in eddy current detection comprises a termination point detection zone made of the same material and uniform with the remainder of the polishing pad. 4A is a cross-sectional view of a polishing pad suitable for polishing a semiconductor substrate according to an embodiment of the present invention and suitable for detecting eddy current endpoints. 4B is a top view of the polishing pad of FIG. 4A according to one embodiment of the present invention.

Referring to FIGS. 4A and 4B, the polishing pad 400 includes a mold-shaped uniform polishing body 402. The mold-shaped uniform polishing body 402 has a polishing surface 404 and a back surface 406. The pattern of the grooves 408 is arranged in the polishing surface 404. Each groove in the pattern of grooves has a bottom depth portion 410. The polishing pad 400 also includes an end-point detection zone 412 formed in a mold-shaped uniform polishing body 402. The endpoint detection zone has a first surface 414 oriented in the same direction as the polishing surface 404 and a second surface 416 oriented in the same direction as the backside 406. At least a portion of the first surface 414 is coplanar with the bottom depth portion 410 in a pattern of grooves, e.g., at a depth D1. The second surface 416 is recessed by about D2 into the uniform polishing body 402 which is molded with respect to the back surface 406. [ In one embodiment, the second surface 416 is recessed to about D2 to fully accommodate an eddy current probe protruding from the platen of the chemical mechanical polishing apparatus. In a particular embodiment, the recess depth D2 is on the order of about 70 mil (1 / 1,000 in) below the surface 406. In one embodiment, because at least a portion of the first surface 414 is coplanar with the bottom depth portion 410 in the pattern of grooves, the first surface 414 may be formed by the movement of the slurry during polishing of the wafer, I never do that.

In one embodiment, at least a portion of the first surface 414 breaks the pattern of the grooves 408 of the polishing surface 404. For example, referring to FIG. 4A in one embodiment, the entire first surface 414 of the endpoint detection zone 412 is generally coplanar with the bottom depth portion 410 in the pattern of the grooves 408. Thus, the pattern of the grooves 408 is disconnected in the end point detection zone 412, since in effect a single large groove is formed on the first surface 414 of the end point detection zone 412. Referring to FIG. 4B, the polishing surface 404 of the mold-shaped uniform polishing body 402 has a pattern of grooves disposed therein. In one embodiment, the pattern of grooves includes a plurality of concentric polygons 418 along a plurality of radial lines 420. However, in the end point detection zone 412, the pattern is disconnected due to the absence of the groove.

Therefore, even if the end point detection zone 412 is made of the same material as the mold-shaped uniform polishing body 402, a visual indicator indicating the position of the end point detection zone 412 is provided. In a specific embodiment, the mold-shaped uniform polishing body 402 including the end-point detection zone 408 is opaque, but the cut-off zone in the pattern of grooves is the end point for mounting on the platen on which the eddy current detection system is installed Is used to visually determine the location of the detection zone 408. [

In another embodiment, the endpoint detection zone has a second pattern of grooves having a depth that is generally coplanar with a bottom depth in a pattern of grooves disposed in the polishing surface of the polishing pad. For example, Figure 5A is a cross-sectional view of another polishing pad according to another embodiment of the present invention. Figure 5B is a top view of the polishing pad of Figure 5A according to an embodiment of the present invention.

Referring to FIGS. 5A and 5B, the polishing pad 500 includes a mold-shaped uniform polishing body 502. The mold-shaped uniform polishing body 502 has a polishing surface 504 and a back surface 506. The pattern of the grooves 508 is disposed within the polishing surface 504. Each groove in the pattern of grooves has a bottom depth portion 510. The polishing pad 500 also includes an end-point detection zone 512 formed in the mold-shaped uniform polishing body 502. The endpoint detection zone has a first surface 514 oriented in the same direction as the polishing surface 504 and a second surface 516 oriented in the same direction as the back surface 506. At least a portion of the first surface 514 is coplanar with the bottom depth portion 510 in a pattern of grooves, e.g., at a depth D1. The second surface 516 is recessed to about D2 into the uniform polishing body 502 which is molded with respect to the back surface 506. [ In one embodiment, the second surface 516 is recessed about D2 to fully accommodate the eddy current probe protruding from the platen of the chemical mechanical polishing apparatus. In a particular embodiment, the recess depth D2 is on the order of about 70 mil (1 / 1,000 in) below the surface 506.

In one embodiment, at least a portion of the first surface 514 breaks the pattern of the grooves 508 of the polishing surface 504. 5A, for example, the first surface 514 of the endpoint detection zone 512 includes a bottom depth portion in the pattern of the grooves 508 disposed within the polishing surface 504, And a second pattern of grooves 518 having a coplanar depth (e.g., on the order of depth D1). However, the pattern of the groove 508 on the polishing surface 504 and the second pattern of the groove 518 in the end point detection zone 512 are disconnected by the change in the space 520. For example, each groove in both the pattern of the groove 508 and the second pattern of the groove 518 has a space of a width W1, and the second pattern of the groove 518 is formed in the groove 508 (W2) which is larger than the width W1 from the first pattern of the first pattern.

Referring to FIG. 5B, the polishing surface 504 of the mold-shaped uniform polishing body 502 has a pattern of grooves disposed therein. In one embodiment, the pattern of grooves includes a plurality of concentric polygons 522 along a plurality of radial lines 524. However, the pattern in the end point detection zone 512 is cut off around the second pattern of grooves 518. Therefore, even if the end-point detection zone 512 is made of the same material as the mold-shaped uniform polishing body 502, a visual indicator indicating the position of the end-point detection zone 512 is provided. In a specific embodiment, the mold-shaped uniform polishing body 502 including the end-point detection zone 508 is opaque, but the disconnection in the pattern of the grooves is accomplished by the end-point detection for mounting on the platen on which the eddy- And is used to visually determine the location of the zone 508.

The use of the cutoff pattern of the groove to visually determine the position of the end point detection zone for mounting on the platen on which the eddy current detection system is installed means that the offset in the groove pattern, as described above, The present invention is not limited to the embodiment that indicates the position of the viewpoint detection zone. In another embodiment, the added groove is included in the polishing surface that follows the contour of the position in the detection zone on the back surface of the polishing pad. In another embodiment, the groove width used in the polishing surface is changed to indicate the position of the detection zone on the back surface of the polishing pad. In another embodiment, the groove pitch used in the polishing surface is changed to indicate the position of the detection zone on the back surface of the polishing pad. In another embodiment, two or more of the above configurations are included in the polishing surface to indicate the position of the detection zone on the back surface of the polishing pad.

According to one embodiment of the present invention, the above-described mold-shaped uniform polishing body is made of a polyurethane material having a thermosetting and closed cell structure. In one embodiment, the term "uniform" is used to indicate that the composition of a thermoset, closed cell structure polyurethane material is constant over the entire composition of the polishing body. For example, in one embodiment, the term "uniform" excludes an abrasive pad made of, for example, a plurality of layers of impregnable felt or composition (composite) of different materials. In one embodiment, the term "thermosetting" is used to designate a polymeric material that is irreversibly cured, such as, for example, the precursor of the material is irreversibly changed to an insoluble, insoluble polymer network by curing. For example, in one embodiment, the term "thermosetting" refers to the removal of a polishing pad made of a "thermoplast" material or "thermoplastic resin " made of a polymer that turns into a liquid phase, do. Polishing pads made of thermosetting materials are typically made from low molecular weight precursors that react to form polymers in chemical reactions, while pads made of thermoplastic materials are used to form pre-existing polymers It is usually produced by heating. In one embodiment, the term "molded-on" is used to indicate that a shaped uniform abrasive article is molded in a forming mold, as described in more detail below.

In one embodiment, the above-described polishing body is opaque. In one embodiment, the term "opaque" is used to indicate a material that permits passage of visible light of approximately 10% or less. In one embodiment, the mold-shaped homogeneous polish body is opaque in most cases, or it has uniform thermosetting properties that make it a mold-shaped homogeneous polish, an opaque lubricant (e.g., additional composition) over the entire polyurethane material of the closed- It is opaque due to its total content. In certain embodiments, the opacifying lubricant is selected from the group consisting of boron nitride, cerium fluoride, graphite, graphite fluoride, molybdenum sulfide, niobium sulfide, ), Mica (talc), tantalum sulfide, tungsten disulfide, or Teflon.

In one embodiment, the mold-shaped uniform polishing body comprises a porogen. In one embodiment, the term "porogen" is used to indicate micro- or nanoscale spherical particles having a "hollow" center. The hollow center is not filled with solid material, but may instead comprise a gas or liquid core. In one embodiment, the mold-shaped homogeneous polishing body is formed by homogeneous thermosetting of the mold-shaped homogeneous polishing body, a pre-foamed and gas-filled EXPANCEL (for example, as an additional component) as a porogen over the molyurethane material of the closed- . In certain embodiments, the EXPANCEL is filled with pentane.

The size of the mold-shaped uniform polishing body can be changed according to the application example. Nonetheless, certain parameters may be used to produce a polishing pad comprising a mold-shaped uniform polishing body that can be used with conventional processing equipment or conventional chemical and mechanical processing operations. For example, according to one embodiment of the present invention, the mold-shaped uniform polishing body has a thickness within the range of about 0.075 in. To 0.130 in., For example, in the range of from 1.9 to 3.3 mm. In one embodiment, the mold-shaped uniform polishing body 202 has a diameter within a range of approximately 20 inches to 30.0 inches, such as approximately 50-77 cm, and has a diameter within a range of approximately 10 inches to 42 inches, It is also possible to have. In one embodiment, the mold-shaped homogeneous polishing body has a pore density in the range of approximately 18% -30% total pore volume, and it is also possible to have a pore density in the range of approximately 15% -35% total pore volume . In one embodiment, the mold-shaped uniform polishing body has a porosity of a closed cell structure type. In one embodiment, the mold-shaped uniform polishing body has a pore size of about 40 microns in diameter, but may be less than 20 microns in diameter, for example. In one embodiment, the mold-shaped uniform polishing body has a compressibility of about 2.5%. In one embodiment, the mold molded uniform polishing body has a density within approximately 0.70-0.90g / cm ³ or approximately 0.95-1.05g / cm ³ range.

The removal rates of various films using a polishing pad, including a mold-shaped uniform polishing body, may be varied depending on the polishing tool, slurry, condition control, or polish recipe used for eddy current detection. However, in one embodiment, the mold-shaped uniform polishing body exhibits a copper removal rate in the range of approximately 30-900 nm / min. In one embodiment, the mold-shaped uniform polishing body exhibits an oxide removal rate within the range of approximately 30-900 nm / min as described herein.

As described above, a polishing pad suitable for eddy current detection can be manufactured by a molding process. In one embodiment, the mold-forming process can be used to produce an abrasive pad having an end-point detection zone made of a material different from the rest of the polishing pad. For example, Figures 6A-6J are cross-sectional views of various processing operations for polishing a semiconductor substrate and fabricating a polishing pad suitable for detecting eddy current endpoints, in accordance with one embodiment of the present invention.

Referring to Figures 6A-6D, a method of making a polishing pad includes initially forming a partially cured endpoint detection zone precursor. 6A and 6B, the first molding mold 602 is filled with the precursor mixture 604 and the lid 606 of the first molding mold 602 is filled with the precursor mixture 604, Respectively. In one embodiment, when the lid 606 is in place, the mixture 604 may be formed from a partially cured body 608 (e.g., a chain extension formed throughout the mixture 604 as shown in Figure 6C) And / or at least a portion of cross-linking). When removing the partially cured body 608 from the first forming mold 602, the partially cured ending point detection region precursor 608 is provided as shown in FIG. 6D.

In one embodiment, the partially cured endpoint detection zone precursor 608 is formed by mixing a urethane-free polymer with a curing agent. In one embodiment, the partially cured endpoint detection zone precursor 608 ultimately provides a local transparent area (LAT) zone within the polishing pad. The LAT zone is suitable for inclusion in a polishing pad made of a material usable with various endpoint detection techniques and produced by a molding process. For example, the partially cured endpoint detection zone precursor 608 is formed by first mixing an aromatic urethane prepolymer with a curing agent. In another embodiment, the opaque zone is formed by including an opacifying agent in the mixture. In either case, the resulting mixture is partially cured in the first shaping mold to provide a molded gel.

6E, the partially cured endpoint detection zone precursor 608 is positioned on the receiving area 614 in the lid 612 of the second forming mold 610. A polishing pad precursor mixture 616 is formed in the second shaping mold 610. According to one embodiment of the present invention, the polishing pad precursor mixture 616 comprises a polyurethane pre-polymer and a curing agent.

In one embodiment, the polishing pad precursor mixture 616 is used to finally form a mold-shaped uniform polishing body made of a polyurethane material of a thermosetting, closed cell structure. In one embodiment, the polishing pad precursor mixture 616 is used to finally form hard pads, and only a single type of curing agent is used. In another embodiment, polishing pad precursor mixture 616 is used to finally form a soft pad, and compositions of primary and secondary curing agents are used. For example, in certain embodiments, the prepolymer comprises a polyurethane precursor, the primary curing agent comprises an aromatic diamine compound, and the secondary curing agent comprises an ether bond. In certain embodiments, the polyurethane precursor is an isocyanate, the primary curing agent is an aromatic diamine, and the secondary curing agent is a curing agent such as, for example, polytetramethylene glycol, amino-functionalized glycol or amino-functionalized polyoxypropylene It is not limited. In one embodiment, the prepolymer, the primary curing agent and the secondary curing agent have a molar ratio of about 100 moles of prepolymer, 85 moles of primary curing agent, and 15 moles of secondary curing agent. It should be understood that various molar ratios may be used to provide varying hardness values to the polishing pad based on the particular properties of the prepolymer and the primary and secondary curing agents. In one embodiment, the mixing further comprises mixing an opacifying lubricant with the prepolymer, the primary curing agent, and the secondary curing agent. In one embodiment, the opacifying agent is, but is not limited to, materials such as, for example, boron nitride, cerium fluoride, graphite, graphite fluoride, molybdenum sulfide, sulfone boiling, mica, tantalum sulfide, tungsten disulfide or Teflon.

In a particular embodiment, the mold-shaped uniform polishing body comprises (a) an aromatic urethane prepolymer such as AIRTHANE 60D (polytetramethylene glycol-toluene diisocyanate), (b) EXPANCEL DE40 (acrylonitrile with isobutane or pentane (D) a polyol such as Terathane 2000 (polyoxytetramethylene glycol) and (e) a catalyst such as DABCO 1027, (f) a CURENE 107 (G) heat stabilizers such as Irgastab PUR68, and (g) microcapsules of substantially the same type, an ultraviolet absorber such as TInuvin 213, which forms an almost opaque light yellow thermosetting polyurethane having a closed cell structure In one embodiment, EXPANCEL is charged with gas, and the average pore size of each EXPANCEL unit is in the range of approximately 20 to 40 microns.

6F, the partially cured endpoint detection zone precursor 608 is moved into the polishing pad precursor mixture 616 by lowering the lid 612 of the second shaping mold 610. In one embodiment, the partially cured endpoint detection zone precursor 608 is moved to the very bottom surface of the second shaping mold 610, as shown in FIG. 6F. In one embodiment, a plurality of grooves are formed in the lid 612 of the forming mold 612. The plurality of grooves are used to stamp the pattern of the grooves on the polishing surface of the polishing pad formed in the forming mold 610. It is shown in the illustrated embodiment that the lid of the forming mold is lowered to move the partially cured endpoint detection zone precursor into the polishing pad precursor mixture and in this embodiment approaching the base of the lid and forming mold is achieved It should be understood that it is only necessary to do so. That is, in some embodiments, the base of the mold is raised toward the lid of the mold while in other embodiments the base is raised toward the lid and the lid of the mold is lowered toward the base of the mold.

6G, a polishing pad precursor mixture 616 and a partially cured endpoint detection zone precursor 608 are provided with a mold-shaped uniform polishing body 620 covalently bonded to a cured endpoint detection zone precursor 622 (E.g., if cover 612 is in place) to provide heat. 6H, a polishing pad (or a polishing pad precursor if a further curing step is required) is removed from the mold 610 to form a mold with a cured endpoint detection zone precursor 622 disposed therein Uniform polishing body 620 as shown in Fig. It is noted that a further curing step after the heating step may be preferred and may be carried out by placing the polishing pad in an oven and heating. In either case, the polishing pad is finally provided, wherein the mold-shaped uniform polishing body 620 of the polishing pad has a polishing surface (upper groove surface in FIG. 6H) and a back surface (a flat bottom surface in FIG. ). In one embodiment, the step of heating the forming mold 610 is a mixture 616 in the forming die 6120 Fahrenheit approximately 200-260 also surrounds the temperature and pressure in about 2-12 lb / in ² ranges within the range And at least partially curing prior to positioning the lid 612.

Finally, referring to Figures 6i and 6j, the cured endpoint detection zone precursor 622 is recessed against the backside of the mold-shaped uniform polishing body 620. The step of recessing provides an end-point detection zone 624 that is disposed in the mold-shaped uniform polishing body 620 and covalently bonded to the mold-shaped uniform polishing body 620 on the polishing pad. For example, a polishing pad that can be obtained in this manner includes, but is not limited to, the polishing pad described in connection with FIGS. 1A and 1B, 2A and 2B, 3A, and 3B.

In accordance with one embodiment of the present invention, the step of recessing the cured endpoint detection zone precursor 622 is performed by routing out a portion of the cured endpoint detection zone precursor 622. In one embodiment, the entirety of the endpoint detection zone 624 is recessed against the backside of the mold-shaped uniform polishing body 620 as shown in Figure 6i and described in connection with Figures la, lb and 3a have. In another embodiment, however, only the inner portion of the endpoint detection zone 624 is recessed against the backside of the mold-shaped uniform polishing body, as shown in Figure 6j and described in connection with Figures 2a, 2b and 3b have.

In another aspect, the mold-forming process can be used to produce a polishing pad having an end-point detection zone made of a material different from the rest of the polishing pad. However, the material used in the endpoint detection zone may be introduced into a mold-forming process on a separate support structure that needs to be accommodated in the mold-molding process. For example, FIGS. 6K-6T are cross-sectional views of various processing operations for polishing a semiconductor substrate and manufacturing an abrasive pad suitable for detecting eddy current endpoints, in accordance with one embodiment of the present invention.

Referring to Figures 6k-6o, a method of making a polishing pad comprises initially forming a partially cured endpoint detection zone precursor on a support structure. For example, referring to FIGS. 6K-61L, the support structure 699 is located within the first forming mold 602. According to one embodiment of the present invention, the support structure 699 has a size that coincides with the bottom of the first forming mold 602. In one embodiment, the support structure 699 is made of a brittle material, such as a non-resilient material, such as a rigid epoxy board. In one embodiment, the support structure 699 is made of a material suitable for withstanding heat of approximately 300 degrees Fahrenheit. In one embodiment, the support structure 699 is made of a material that is capable of withstanding a high temperature limit, which in certain embodiments allows the support structure 699 to be used repeatedly in the mold molding process shown in Figures 6k to 6t. Because it is recycled. In one embodiment, the support structure 699 is made of a heat insulating material that avoids heat transfer through the support structure 699 during the molding process. In one embodiment, the support structure 699 is made of a chemically inert material and is not covalently bonded to the polyurethane material during the curing process. In one embodiment, the support structure 699 is made of a negligible material such that no gas is evolved upon heating.

6M-6O, the first molding mold 602 is filled with the precursor mixture 604 on the support structure and the lid 606 of the first molding mold 602 is placed on top of the mixture 604 . In one embodiment, when the lid 606 is in place, the mixture 604 may be partially cured 608 (e.g., as shown in Figure 6n, To at least a portion of the cross-linking and / or chain extension formed over the entire length of the web). When removing the partially cured body 608 and the bonded support structure 699 in the first shaping mold 602, the partially cured endpoint detection zone precursor 608 is removed from the support structure 699 as shown in Figure 6O, . In one embodiment, the polymer film is attached to the upper surface of the support structure 699 with a piece of double-sided tape prior to adding the mixture to the first forming mold 602. Thus, in one embodiment, the partially cured body 608 is bonded to the support structure 699 by a polymer film and a piece of double-sided tape.

6P and 6Q, the partially cured endpoint detection zone precursor 608 and the combined support structure 699 are positioned in the receiving area 614 'in the lid 612' of the second forming mold 610, . In one embodiment, the polymer film is disposed, for example, between a partially cured endpoint detection zone precursor 608 and a support structure 699, with a first piece of double-sided tape, and a second piece of double- Is used to bond the structure 699 to the surface in the receiving area 614 'of the lid 612'. A polishing pad precursor mixture 616 is formed in the second shaping mold 610. According to one embodiment of the present invention, the polishing pad precursor assembly 616 comprises a polyurethane pre-polymer and a curing agent.

6R, the partially cured endpoint detection zone precursor 608 is lowered from the second forming mold 610, such as supported by the support structure 699, to form a polishing pad precursor mixture 616). In one embodiment, the partially cured endpoint detection zone precursor 608 is moved to the very bottom surface of the second shaping mold 6010. The polishing pad precursor mixture 616 and the partially cured endpoint detection zone precursor 608 and support structure 699 provide a mold-shaped uniform polishing body 620 that is crosslinked with the endpoint detection zone precursor 622 (E.g., when lid 612 'is in place).

Referring to Figure 6s, a polishing pad (or polishing pad precursor where a further curing step is required) is removed from the mold 610 to form a mold-shaped Thereby providing a uniform polishing body 620. However, in one embodiment, the support structure 699 remains bonded to the cured endpoint detection zone precursor 622 after being removed from the mold 610, as shown in Figure 6S. Note that a further curing step may be required through a heating step and is performed by placing the polishing pad in the oven and heating. In either case, the polishing pad is finally provided, wherein the mold-shaped uniform polishing body 620 of the polishing pad has only the polishing surface (the upper, groove surface in FIG. 6 S) and the back surface (the flat bottom surface in FIG. 6 S) But has a support structure 699. Thus, in one embodiment, the support structure 699 needs to be removed to provide a polishing pad, e.g., removing the double-sided tape adjacent the support structure 699 from the cured endpoint detection zone precursor 622 . In one embodiment, the support structure 699 is removed and then the cured endpoint detection zone precursor 622 is recessed as described above with respect to Figures 6i and 6j to provide a recessed endpoint detection zone Thereby providing an abrasive pad.

Referring to Figure 6t, the support structure 699 remains bonded to the receiving area 614 'of the lid 612' when the polishing pad is removed from the mold 610. That is, the support structure 699 is detached from the finish-point detection zone precursor 620 when the cover 612 'is lifted from the mold 610. However, in other embodiments, the support structure 699 may be difficult to remove the lid 612 '. Thus, in one embodiment, an opening or outlet 690 is provided in lid 612 '. When removing the cover 612 'from the forming mold 610, the air or inert gas is pushed through the opening to separate the support structure 699 from the receiving space 614'. In a particular embodiment, the support structure 699 is then reused in the next mold forming process.

In another embodiment, the cured endpoint detection zone precursor may comprise a sacrificial layer, and the step of recessing is performed by moving the sacrificial layer. For example, Figures 7A-7C are cross-sectional views of various processing operations for polishing a semiconductor substrate and for manufacturing an abrasive pad suitable for detecting eddy current endpoints, in accordance with one embodiment of the present invention.

7A, the partially cured endpoint detection zone precursor 708 is lowered by lowering the lid 612 of the mold 610 having a partially cured endpoint detection zone precursor 708 thereon to form a polishing pad precursor mixture (616). However, in one embodiment, the partially cured endpoint detection precursor 708, which is different from the partially cured endpoint detection zone precursor 608, comprises a sacrificial layer 709 disposed thereon. Thus, the partially cured endpoint detection zone precursor 708 is not solely inserted into the polishing pad precursor mixture 616, and then does not move toward the bottom surface of the forming mold 610. Rather, the sacrificial layer 709 is bonded to the partially cured endpoint detection zone precursor 708 prior to positioning the endpoint detection zone precursor 708 over the lid 612 of the mold 610. The partially cured endpoint detection zone precursor 708 and the sacrificial layer 709 are then moved together toward the bottom surface of the forming mold 610, as shown in FIG. 7A. Thus, the sacrificial layer 709 lies between the bottom of the mold and the partially cured endpoint detection zone precursor 708. In one embodiment, the sacrificial layer 709 comprises a composite material comprising a Mylar film layer as a composition.

7B, a polishing pad precursor mixture 616 and a partially cured endpoint detection zone precursor 708 are used to provide a mold-shaped uniform polishing body 620 that is covalently bonded to an endpoint detection zone 722 (E.g., if lid 612 is in place) under pressure. 7C, the polishing pad is removed from the mold 610 to provide a mold-shaped uniform polishing body 620 having a finish-point detection zone 722 and a sacrificial layer 709 disposed therein. According to one embodiment of the present invention, the step of recessing the eddy current detection region in the polishing pad is accomplished by removing the sacrificial layer 709 as shown in FIG. 7D. In one embodiment, the entire endpoint detection zone 722 is recessed with respect to the back side of the mold-shaped uniform polishing body 620 as also shown in FIG. 7D.

According to one embodiment of the present invention, the endpoint detection zone (e.g., 624 in FIG. 6i or 722 in FIG. 7d) may be configured as shown in FIGS. 1a and 1b, 2a and 2b, And is made of a material different from the mold-shaped uniform polishing body. For example, in one embodiment, the endpoint detection zone 624 or 722 is a local transparent area (LAT) zone as shown in conjunction with FIGS. 1A and 1B, 2A, and 2B. In one embodiment, the endpoint detection zones 624 and 722 are opaque regions having a hardness different from the hardness of the mold-shaped uniform polishing body 620 as shown in association with FIGS. 3A and 3B. In one embodiment, the mold-shaped uniform polishing body 620 is made of a polyurethane material of a thermosetting, closed cell structure. In one embodiment, the polishing surface of the mold-shaped uniform polishing body 620 includes a pattern of grooves disposed therein and formed from the cover of the second forming mold 610.

As described briefly above, in one embodiment, the endpoint detection zone 624 (or 722) and the mold-shaped uniform polishing body 620 may have different hardnesses. For example, in one embodiment, the mold-shaped uniform polishing body 620 has a hardness that is smaller than the hardness of the end-point detection zone 624. In certain embodiments, the mold-shaped uniform polishing body 620 has a hardness in the range of approximately 20-45 Shore D, while the endpoint detection zone 624 has a hardness on the order of approximately 60 Shore D. Even when the hardness is different, the cross-linking between the covalent bond and / or the endpoint detection zone 624 and the mold-shaped uniform polishing body 620 is still wide. For example, according to one embodiment of the present invention, the difference in hardness between the mold-shaped uniform polishing body 620 and the endpoint detection zone 624 is greater than 10 Shore D, but the covalent bond and / The range of cross-linking between the sieve 620 and the endpoint detection zone 624 is substantial.

The dimensions of the polishing pad and the endpoint detection zone disposed therein may vary depending on the target application. For example, in one embodiment, the polishing pad is made to accommodate an eddy current probe, and the mold-shaped uniform polishing body 620 is circular with a diameter in the range of approximately 75-78 cm, while the end- Shaped uniform polishing body 620 having a length in the range of about 4-6 cm along the radial axis of the mold-shaped uniform polishing body 620 and a width of about 1-2 cm, 20 cm.

With respect to vertical positioning, the position of the end point detection zone in the polishing body can be selected according to the specific application and can also be the result of a molding process. For example, achievable positioning and precision, including the endpoint detection zone in the polishing body by a mold-forming process, is much better than the process in which the polishing pad is cut after molding and the window insert is added after molding of the polishing pad The end point detection zone 624 is included in the mold-shaped uniform polish body 620, and the mold-shaped uniform polish body 620 ) On the same plane as the bottom of the groove surface. In a specific embodiment, the endpoint detection zone 624 includes an endpoint detection zone 624 that is coplanar with the bottom of the groove surface in the abrasive body, and the endpoint detection zone 624 includes a mold- And is not disturbed by the CMP processing operation over the lifetime of the polishing pad made in the detection zone 624.

As described above, a polishing pad suitable for eddy current detection is manufactured by a molding process. However, the polishing pad need not include LAT or other distinct material regions. 8A-8F are cross-sectional views of various processing operations for polishing a semiconductor substrate and fabricating a polishing pad suitable for detecting eddy current endpoints, in accordance with one embodiment of the present invention.

Referring to FIG. 8A, a method of manufacturing a polishing pad includes forming a polishing pad precursor mixture 616 in a forming mold 610. 8A and 8B, the lid 612 of the forming mold 610 is located within the polishing pad precursor mixture 616. [ The cover 612 includes a pattern of grooves disposed thereon. The pattern of grooves 618 has a cut-off area 614 in which the pattern is different or somewhat separate from most of the grooves 618, as described in more detail below.

Referring to FIG. 8C, the polishing pad precursor mixture 616 is heated to provide a mold-shaped uniform polishing body 620. 8D, the mold-shaped uniform polishing body 620 is removed from the forming mold 610 so that the polishing pad (or, if a further heating step or curing step is required after the molding process, Precursor). The polishing pad made of the mold-shaped uniform polishing body 620 includes a polishing surface 822 and a back surface 824. [ According to one embodiment of the present invention, the pattern of grooves 618 in the cover 612 of the forming mold and including the cut-off area 614 is disposed within the polishing surface 822 as shown in FIG. 8D. The pattern of grooves disposed in the abrasive surface 822 has a bottom depth portion 826. In one embodiment, the mold-shaped uniform polishing body 620 is made of a polyurethane material of a thermosetting, closed cell structure.

Referring to FIGS. 8E and 8F, the end point detection zone 830 is provided in a mold-shaped uniform polishing body 620. The endpoint detection zone has a first surface 832 oriented in the same direction as the polishing surface 822 and a second surface 834 oriented in the same direction as the mold-shaped uniform polishing body 620. At least a portion of the first surface 832 is flush with the bottom depth portion 826 in the pattern of grooves. For example, in one embodiment, the entire first surface 832 is flush with the bottom depth portion 826 in the pattern of the grooves, as shown in FIG. 8E. In addition, the second surface 834 is recessed into a uniform polishing body 620 which is molded with respect to the back surface 824 as also shown in FIG. 8E. In one embodiment, providing the endpoint detection zone 830 is performed by routing out a portion of the mold-shaped uniform polishing body 620. In one embodiment, the mold-shaped uniform polishing body 620 including the end-point detection zone 830 is opaque.

According to one embodiment of the present invention, as described above, the polishing surface 822 includes a cutting zone of the polishing surface in a pattern of grooves. The cut-off area coincides with the cut-off area in the cover 612 at the forming mold 610. In one embodiment, as shown in FIGS. 8A and 8E, the cut-off area 614 is completely flat and flush with the bottom of the lid 612. Thus, the entire first surface 832 of the endpoint detection zone 830 can have a bottom depth portion 826 in the pattern of grooves in the abrasive surface 822, as shown relative to the polishing pad in Figures 4A and 4B. ). However, in an alternative embodiment, the first surface of the endpoint detection zone 830 is substantially coplanar with the bottom depth in the pattern of grooves disposed within the abrasive surface 822 of the mold-shaped uniform polishing body 820 And a second pattern of grooves 850 with depth portions. This alternative embodiment is shown in Figure 8f. The polishing pad is consistent with this embodiment described above with respect to Figures 5A and 5B. In a particular embodiment, each groove in both the pattern of grooves (at the abrasive surface 822) and the second pattern of grooves (in the cut-off zone) is spaced apart by a width, And offset from the first pattern of grooves by a distance greater than the width from the first pattern of grooves as also shown with respect to FIG. 5B.

In another aspect of the present invention, the endpoint detection zone in the mold-shaped uniform polishing body is formed by removing the sacrificial layer. For example, in accordance with one embodiment of the present invention, Figs. 9A to 9F show a method of manufacturing a polishing pad having an endpoint detection zone provided therein by removing a sacrificial layer buried in a mold- Sectional view of the branch processing operation.

Referring to Fig. 9A, a sacrificial layer 709 is disposed at the bottom of the forming mold 610. Fig. For example, in one embodiment, the sacrificial layer 709 is inserted into the forming mold prior to adding the polishing pad components to the mold. In a particular embodiment, the sacrificial layer 709 comprises a Mylar film layer. Referring to FIG. 9B, the polishing pad precursor mixture is distributed within the forming mold 610, covering the sacrificial layer 709. 9C, when the lid 612 is in position in the forming mold 610, the polishing pad precursor mixture 616 is transferred from the mold-shaped uniform polishing body 620 Is heated to provide. However, the sacrificial layer 709 disposed at the bottom of the forming mold 610 remains during the molding of the mold-shaped uniform polishing body 620.

9D, the mold-shaped uniform polishing body 620 is removed from the forming mold and the polishing pad (or, further, the step of heating or curing) with the sacrificial layer 709 disposed therein is subjected to a mold- If necessary, a precursor to the polishing pad). 9E and 9F, the end point detection zone 924 is provided in the mold-shaped uniform polishing body 620 when the sacrificial layer 709 is removed. Thus, in accordance with one embodiment of the present invention, the step of recessing the eddy current detection zone of the polishing pad is accomplished by removing a sacrificial layer 709 that is flush with the backside of the polishing pad. In one embodiment, the entire end point detection zone 924 is recessed with respect to the back side of the mold-shaped uniform polishing body 620 as shown in Figs. 9E and 9F. In one embodiment, the entire top surface 950 of the endpoint detection zone 924 is recessed and flat as shown in FIG. 9E. However, in another embodiment, the second set of grooves 952 in the mold-shaped uniform polishing body 620 is disposed on the upper surface of the end-point detection zone 924 as shown in FIG. 9F.

In yet another embodiment, the recessed area for the polishing pad can be manufactured by positioning or integrating the raised member in the bottom of the mold used to form the polishing pad. For example, referring again to FIGS. 9A-9C, the area blackened in place of the sacrificial layer 709 may be a permanent or semi-permanent member made in the mold 610. That is, this member does not deliver the manufactured polishing pad in contrast to the sacrificial layer 709 delivered from the mold with the fabricated polishing pad (e.g., as described in connection with FIG. 9d). In this case, in one embodiment, the polishing pad of uniform polishing body 620, as shown in Figures 9e and 9f, may be used without the need to remove the sacrificial layer in the middle (as described in other ways with respect to Figure 9d) Lt; RTI ID = 0.0 > mold). ≪ / RTI > In another embodiment, a permanent or semi-permanently shaped member made in a forming mold may be used with a padding of two materials suitable for manufacturing a polishing pad, for example as described in connection with Figs. 1A, 2A, 3A and 3B do.

The polishing pad shown here is suitable for use with a chemical mechanical polishing apparatus installed with an eddy current endpoint detection system. For example, Figure 10 is an isometric view of an abrasive device that may be used with a polishing pad suitable for detecting an eddy current endpoint in accordance with one embodiment of the present invention.

Referring to Fig. 10, the polishing apparatus 1000 includes a platen 1004. The top surface 1002 of the platen 1004 may be used to support a polishing pad for eddy current detection. Platen 1004 is configured to provide spindle rotation 1006 and slider oscillation 1008. The sample carrier 1010 is used to hold the semiconductor wafer 1011 in place while polishing, for example, a semiconductor wafer with a polishing pad. The sample carrier 1010 is also supported by a suspension mechanism 1012. Slurry supply 1014 is included to provide slurry to the surface of the polishing pad before polishing and polishing the semiconductor wafer.

In one aspect of the invention, a polishing pad suitable for detecting an eddy current endpoint is provided for use with a polishing apparatus similar to polishing apparatus 1000. For example, FIG. 11 is a cross-sectional view of an abrasive apparatus having an abrasive pad usable with an eddy current endpoint detection system and an eddy current endpoint detection system, in accordance with an embodiment of the present invention.

11, the polishing apparatus 1000 includes a rotatable platen 1004 on which a polishing pad 1118 rests. The polishing pad 1118 provides a polishing surface 1124. At least a portion of the polishing surface 1124 may have a groove 1128 for transporting the slurry. The polishing apparatus 1000 also includes a polishing pad conditioner that maintains conditioning of the polishing pad, thereby effectively polishing the substrate. During the polishing operation, the chemical mechanical polishing slurry 1130 is supplied to the surface of the polishing pad 1118 by a slurry supply port or an associated slurry / rinse arm 1014. The substrate 1011 is held against the polishing pad 1118 by the carrier head portion 1010. The carrier head portion 1010 is draped from the support structure, such as a carousel, and is connected to the carrier head rotation motor by a carrier drive shaft 1136 such that the carrier head portion can rotate about an axis 1138.

The recess 1140 is formed in the platen 1004 and the in situ monitoring module 1142 is embedded within the recess 1140. The position monitoring module 1142 includes a positional eddy current monitoring system with a core 1144 positioned within a recess 1140 that rotates with the platen 1004. The drive and sense coils 1146 are wound on a core 1144 and are connected to a controller 1150. In operation, the oscillator energizes the drive coil to generate a swinging magnetic field 1148 that extends through the body of the core 1144. At least a portion of the magnetic field 1148 passes through the polishing pad 1118 and extends toward the substrate 1011. If a metal layer is present on the substrate 1011, the oscillating magnetic field 1148 will generate an eddy current.

The eddy current generates a magnetic flux in the opposite direction of the induced magnetic field, which induces a reverse current in the sense or in the sense coil in the opposite direction of the drive current. The resulting change in current can be measured as a change in impedance at the coil. As the thickness of the metal layer changes, the resistance of the metal layer can be changed. Therefore, the magnitude of the magnetic flux induced by the eddy current and the eddy current can also be changed, causing a change in the impedance of the primary coil. For example, by measuring the phase of the coil current with respect to the magnitude of the coil current or the phase of the drive coil current and monitoring these changes, the eddy current sensor monitor can detect a change in the thickness of the metal layer.

11, according to one embodiment of the present invention, when the polishing pad 1118 is secured to the platen 1004, the thin portion fits over the recesses 1140 in the plate and the upper portion of the platen 1004 Or over a portion of the core and / or coil that protrudes beyond the plane of the plane. By positioning the core 1142 near the substrate 1112, the magnetic field can be less spread and the spatial resolution can be improved. If the polishing pad 1011 is not used with the optical termination point monitoring system, in one embodiment, the entire polishing layer, including a portion on the recess, may be opaque. However, in other embodiments, a portion of the recess is transparent, which helps position the polishing pad on the platen.

According to one embodiment of the present invention, the problem addressed here is that the sensor includes a case in which the eddy current endpoint detection hardware includes a sensor rising about 0.070 inches above the plane of the platen, . However, in this case, some problems may arise in the design and performance of the polishing pad in which embodiments of the present invention provide an advantageous solution. In one embodiment, the polishing pad is typically designed to accommodate the eddy current sensor by a recess formed in the backside of the polishing pad. In certain embodiments, a recess of about 0.080 in depth in the polishing pad is used for this purpose.

In one aspect of the invention, a polishing pad designed to accommodate an eddy current detection system, such as the polishing pad described in various embodiments above, is attached to the platen 1004 by an adhesive surface. For example, in one embodiment, an adhesive without a carrier film (i.e., a transfer adhesive) can be used to bond the polishing pad to the platen 1004 with an adhesive. In this case, the openings do not need to be inserted into the temporary or sacrificial release liner removed from the polishing pad before being transferred to the platen, because the permanent carrier film is not carried with the pad to the platen. In one embodiment, the temporary or sacrificial release liner is removed from the polishing pad and the adhesive membrane is left. A portion of the adhesive membrane that intersects the recesses in the polishing pad (such as recesses formed to accommodate the eddy current detection system) will remain with the release liner or remain as a membrane across the opening of the recess. In the latter case, that portion of the membrane will need to be removed from the opening of the recess that traverses before mounting the polishing pad on the platen, and any of the sacrificial release liner or adhesive membrane remaining on the polishing pad It's not a tape.

 As described above, there is disclosed a polishing pad for polishing a semiconductor substrate used for detecting an eddy current end point. According to one embodiment of the present invention, a polishing pad for polishing a semiconductor substrate includes a uniform polishing body. The mold-shaped uniform polishing body has a polishing surface and a back surface. The polishing pad also includes an end-point detection zone disposed in the mold-shaped uniform polishing body and covalently bonded to the mold-shaped uniform polishing body. The end point detection zone is made of a material different from the mold-shaped uniform polish body, and at least a part of the end point detection zone is recessed with respect to the back surface of the mold-shaped uniform polish body. According to another embodiment of the present invention, a polishing pad for polishing a semiconductor substrate includes a mold-shaped uniform polishing body having a polishing surface and a back surface. The pattern of the groove is disposed on the polishing surface, and the pattern of the groove has the bottom depth portion. The polishing pad also includes an end-point detection zone formed in the mold-shaped uniform polishing body. The endpoint detection zone has a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface. At least a portion of the first surface is coplanar with the bottom depth portion in the pattern of grooves and breaks the pattern of grooves. The second surface is recessed into a uniform polishing body which is molded with respect to the back surface.

Claims (20)

A polishing pad for polishing a semiconductor substrate,
A mold-shaped uniform polishing body including a polishing surface and a back surface;
A pattern of grooves disposed on the polishing surface and having a bottom depth; And
Wherein the eddy current end point detection zone has a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface, the eddy current end point detection zone being formed in the mold-shaped uniform polishing body, Wherein at least a portion of the first surface is coplanar with the bottom depth in the pattern of grooves and the pattern of grooves is broken due to the absence of grooves or due to the presence of a pattern of different grooves, Wherein said eddy current end point detection zone is defined by said uniformly polished surface,
Wherein the polishing pad comprises a polishing pad for polishing a semiconductor substrate. The method according to claim 1,
Wherein the entire first surface of the eddy current end point detection zone is flush with the bottom depth in the pattern of grooves. The method according to claim 1,
Wherein the first surface of the eddy current end point detection zone comprises a second pattern of grooves having a depth that is coplanar with the bottom depth in the pattern of grooves disposed on the polishing surface . The method of claim 3,
Each groove in both the pattern of grooves and the second pattern of grooves being spaced apart by a width,
Wherein the second pattern of grooves is offset from the pattern of the grooves by a distance greater than the width. The method according to claim 1,
Wherein the mold-shaped uniform polishing body comprises a polyurethane material of a thermosetting, closed cell structure. The method according to claim 1,
Wherein the mold-shaped uniform polishing body and the eddy current end point detection region are opaque. A method of manufacturing a polishing pad for polishing a semiconductor substrate,
Forming a polishing pad precursor mixture in the forming mold;
Positioning the lid of the forming mold in the polishing pad precursor mixture, the lid having a pattern of grooves disposed on the lid, the pattern of grooves having a cutting zone, the cutting zone having a pattern of grooves Positioning the lid of the forming mold, wherein the lid is a section that is disconnected due to absence or due to the presence of a pattern of different grooves;
Curing the polishing pad precursor mixture to provide a mold-shaped uniform polishing body comprising a polishing surface and a back surface, wherein a pattern of the grooves in the cover is disposed on the polishing surface, Curing the polishing pad precursor mixture; And
Providing a eddy current end point detection zone in the mold-shaped uniform polishing body, wherein the eddy current end point detection zone includes a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface Wherein at least a portion of the first surface is coplanar with the bottom depth in the pattern of grooves and includes a cut-off area in the pattern of grooves, Wherein the eddy current end point detection zone is recessed into the uniform uniform polishing body
≪ / RTI > The method of claim 1, wherein the polishing pad is a metal. 8. The method of claim 7,
Wherein providing the eddy current end point detection zone is performed by routing out a portion of the mold-shaped uniform polishing body. 8. The method of claim 7,
Wherein the step of providing the eddy current end point detection zone is performed by removing a sacrificial layer buried in the mold-shaped uniform polishing body. 8. The method of claim 7,
Wherein the entire first surface of the eddy current end point detection zone is flush with the bottom depth portion in the pattern of the groove. 8. The method of claim 7,
Wherein the first surface of the eddy current end point detection zone includes a second pattern of grooves having a depth portion coplanar with the bottom depth portion in the pattern of the grooves disposed on the polishing surface of the mold-shaped uniform polishing body ≪ / RTI > characterized in that the polishing pad is polished. 12. The method of claim 11,
Wherein each groove in both the pattern of grooves and the second pattern of grooves is spaced apart by a width and the second pattern of grooves is offset by a distance greater than the width from the pattern of grooves. A method of manufacturing a polishing pad for polishing a semiconductor substrate. 12. The method of claim 11,
Characterized in that the mold-shaped uniform polishing body comprises a polyurethane material of a thermosetting, closed cell structure. 8. The method of claim 7,
Characterized in that the mold-shaped uniform polishing body and the eddy current end point detection region are opaque. A method of manufacturing a polishing pad for polishing a semiconductor substrate,
The method includes forming a polishing pad by a mold forming process,
The polishing pad comprises:
A uniform polishing body having a polishing surface and a back surface;
A pattern of grooves disposed on the polishing surface and having a bottom depth; And
Wherein the eddy current end point detection zone has a first surface oriented in the same direction as the polishing surface and a second surface oriented in the same direction as the back surface, the eddy current end point detection zone being formed in the mold-shaped uniform polishing body, Wherein at least a portion of the first surface is flush with the bottom depth portion in the pattern of grooves and the pattern of grooves is cut off due to the absence of grooves or due to the presence of a pattern of different grooves, Wherein said eddy current end point detection zone is recessed into said mold-shaped uniform polishing body with respect to the back surface,
≪ / RTI > The method of manufacturing a polishing pad for polishing a semiconductor substrate according to claim 1, 16. The method of claim 15,
Wherein the entire first surface of the eddy current end point detection zone is flush with the bottom depth portion in the pattern of the groove. 16. The method of claim 15,
Wherein the first surface of the eddy current end point detection zone includes a second pattern of grooves having a depth that is coplanar with the bottom depth of the pattern of grooves disposed on the polishing surface. Of the polishing pad. 18. The method of claim 17,
Characterized in that each groove in both the pattern of grooves and the second pattern of grooves is spaced apart by a width and the second pattern of grooves is offset by a distance greater than the width from the pattern of grooves. A method of manufacturing a polishing pad for polishing a substrate. 16. The method of claim 15,
Characterized in that the mold-shaped uniform polishing body comprises a polyurethane material of a thermosetting, closed cell structure. 16. The method of claim 15,
Characterized in that the mold-shaped uniform polishing body and the eddy current end point detection region are opaque.

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