CN118123702A

CN118123702A - Microlayer CMP polishing sub-pad

Info

Publication number: CN118123702A
Application number: CN202311615797.1A
Authority: CN
Inventors: 侯冠华; B·E·巴尔顿; A·阿尔斯拜伊; A·旺克; 王德纯; A·M·克洛万斯; N·A·瓦斯克斯; J·R·麦考密克
Original assignee: Rohm and Haas Electronic Materials CMP Holdings Inc
Current assignee: Rohm and Haas Electronic Materials CMP Holdings Inc
Priority date: 2022-12-01
Filing date: 2023-11-29
Publication date: 2024-06-04

Abstract

The polishing pad has a polymer matrix for polishing a polishing surface of at least one of a semiconductor, magnetic, and optical substrate and a bottom surface; a porous subpad adhered to the bottom surface of the polishing pad. The porous subpad comprises a nonporous microlayer for securing the polishing pad to the porous subpad. The porous polymer network comprises i) a single layer of closed cell pores adjacent to the nonporous microlayer for transferring compressive forces from the bottom surface of the polishing pad to the porous subpad; and ii) a plurality of closed cells, open cells or a mixture of closed and open cells adjacent to the single-layer closed cells.

Description

Microlayer CMP polishing sub-pad

Cross Reference to Related Applications

This is a continuation-in-part application of U.S. Ser. No. 18/060,669 filed on day 2022, month 12, and day 1.

Background

The invention relates to a chemical mechanical polishing sub-pad. More particularly, the present invention relates to a chemical mechanical polishing sub-pad having micro-pores.

In the fabrication of integrated circuits and other electronic devices, multiple layers of conductive, semiconductive, and dielectric materials are deposited onto and removed from the surface of a semiconductor wafer. Many deposition techniques may be used to deposit thin layers of conductive, semiconductive, and dielectric materials. Common deposition techniques in modern wafer processing include, inter alia, physical Vapor Deposition (PVD) (also known as sputtering), chemical Vapor Deposition (CVD), plasma Enhanced Chemical Vapor Deposition (PECVD), and electrochemical plating. Common removal techniques include wet and dry isotropic and anisotropic etching, among others.

As the material layers are sequentially deposited and removed, the uppermost surface of the wafer becomes non-planar. Since subsequent semiconductor processing (e.g., photolithography) requires the wafer to have a planar surface, planarization of the wafer is required. Planarization is used to remove undesirable surface topography and surface defects such as rough surfaces, agglomerated materials, lattice damage, scratches, and contaminated layers or materials.

Chemical mechanical planarization, or Chemical Mechanical Polishing (CMP), is a common technique for planarizing or polishing a workpiece, such as a semiconductor wafer. In conventional CMP, a wafer carrier or polishing head is mounted on a carrier assembly. The polishing head holds the wafer and positions the wafer in contact with a polishing layer of a polishing pad mounted on a platen or platen within the CMP apparatus. The carrier assembly provides a controllable pressure between the wafer and the polishing pad. At the same time, a polishing medium (e.g., slurry) is dispensed onto the polishing pad and is drawn into the gap between the wafer and the polishing layer. For polishing, the polishing pad and wafer typically rotate relative to one another. As the polishing pad rotates beneath the wafer, the wafer sweeps out a typically annular polishing track or polishing zone, with the surface of the wafer directly facing the polishing layer. The wafer surface is polished and planarized by chemical and mechanical action of the polishing layer and polishing media on the surface.

The CMP process typically occurs in two steps or three steps on a single polishing tool. The first step is to planarize the wafer and remove a large portion of the excess material. After planarization, a subsequent step or steps remove scratches or scratches introduced during the planarization step. Polishing pads for these applications must be soft and conformal to polish the substrate without scratching. In addition, the polishing pad must provide planarized bulk polishing at a uniform rate to achieve excellent wafer throughput. Traditionally, CMP equipment settings such as downforce, wafer speed, platen speed, polishing pad thickness, subpad compressibility, slurry flow rate, and wafer head pressure settings are combined to improve global planarization. Nonetheless, the last few millimeters to several millimeters adjacent to the wafer edge is typically subject to edge fast or edge slow removal rates.

Despite efforts for years, challenges remain to further reduce yield loss associated with edge fast and edge slow polishing or planarization. Thus, there remains a need for efforts to reduce edge effects and improve wafer yield.

Disclosure of Invention

One aspect of the present invention provides a chemical mechanical polishing pad comprising: a polishing pad having a polymer matrix for polishing a polishing surface of at least one of a semiconductor, magnetic, and optical substrate and a bottom surface; a porous subpad adhered to the bottom surface of the polishing pad, the porous subpad comprising: a non-porous microlayer for securing the polishing pad to the porous subpad, the non-porous microlayer being flexible and forming a micron-sized conformal coating on the bottom surface of the polishing pad and the non-porous layer being contiguous with the bottom surface of the polishing pad; a porous polymer network comprising: i) A single layer of closed cell pores adjacent to the nonporous microlayer for transferring compressive forces from the bottom surface of the polishing pad to the porous subpad; and ii) a plurality of closed cells, open cells, or a mixture of closed cells and open cells adjacent to the single-layer closed cells, wherein the plurality of closed cells, open cells, or mixture of closed cells and open cells is aerated and the plurality of closed cells, open cells, or mixture of closed cells and open cells remains aerated throughout the polishing life of the polishing pad.

Another aspect of the present invention provides a chemical mechanical polishing pad comprising: a polishing pad having a polymer matrix for polishing a polishing surface of at least one of a semiconductor, magnetic, and optical substrate and a bottom surface; a porous subpad adhered to the bottom surface of the polishing pad, the porous subpad comprising: a non-porous microlayer for securing the polishing pad to the porous subpad, the non-porous microlayer being flexible and forming a micron-sized conformal coating on the bottom surface of the polishing pad and the non-porous layer being contiguous with the bottom surface of the polishing pad; a porous polymer network comprising: i) A single layer of closed cell pores adjacent to the nonporous microlayer for transferring compressive forces from the bottom surface of the polishing pad to the porous subpad; and ii) a plurality of closed cells, open cells, or a mixture of closed cells and open cells adjacent to the single-layer closed cells, wherein the plurality of closed cells, open cells, or mixture of closed cells and open cells is aerated and the plurality of closed cells, open cells, or mixture of closed cells and open cells remains aerated throughout the polishing life of the polishing pad, and the polishing pad has a porosity and the porous subpad has a porosity greater than the porosity of the polishing pad.

Drawings

FIG. 1 is a schematic view of a polishing pad having closed cell pores in the polishing pad.

FIG. 2 is a schematic view of the polishing pad of FIG. 1, showing the nonporous microlayer of the porous subpad, wherein the remainder of the porous subpad is peeled away.

FIG. 3 is a schematic illustration of the polishing pad of FIG. 2, wherein a single layer of closed cell pores is adjacent to a non-porous microlayer, wherein the remainder of the porous subpad is peeled away.

FIG. 4 is a schematic illustration of the polishing pad of FIG. 3 having multiple layers of open and closed cells adjacent to a single layer of closed cells.

FIG. 4A is a schematic illustration of the polishing pad of FIG. 3 having multiple closed cells adjacent to a single closed cell.

FIG. 4B is a schematic illustration of the polishing pad of FIG. 3 having a plurality of open cells adjacent to a single layer of closed cells.

FIG. 5 is a schematic view of a polishing pad having a non-porous layer conforming to a bottom surface of the polishing pad.

FIG. 6 is a schematic view of a polishing pad having multiple layers of open and closed cell pores adjacent to a non-porous layer.

FIG. 6A is a schematic view of a polishing pad having multiple layers of closed cells adjacent to a non-porous layer.

FIG. 6B is a schematic illustration of a polishing pad having a plurality of open-celled pores adjacent to a non-porous layer.

Fig. 7 is a bottom view of a polishing pad with a recessed subpad.

Fig. 7A is a cross-section taken through the center of the polishing pad of fig. 7.

FIG. 8 is a top view of a polishing pad having concentric circular grooves with annular recessed grooves.

Fig. 8A is a cross-section taken through the center of the polishing pad of fig. 8, showing the subpad filling the vertical and tapered annular recess in the polishing pad.

FIG. 9 is a top view of a polishing pad having concentric circular grooves with annular recessed grooves.

Fig. 9A is a cross-section taken through the center of the polishing pad of fig. 9, showing the subpad filling the vertical and airfoil-shaped annular recess in the polishing pad.

Detailed Description

The chemical mechanical polishing pad of the present invention is useful for polishing at least one of semiconductor, magnetic, and optical substrates. The polishing pad has a polymer matrix, such as a polyurethane, polyurea, or polyurethane-urea polymer matrix. In particular, chemical mechanical polishing pads are used for polishing semiconductor wafers and in particular for low defect planarization of semiconductor wafers. Advantageously, all components of the subpad have the same polymer composition.

Referring to fig. 1, a polishing pad 10 has a polishing layer 12. The polishing layer 12 has a polishing surface 14 and is formed of a polymer matrix. The polishing pad also has a bottom surface 16 that defines the polishing pad 10. Advantageously, the polishing pad 10 has a consistent polymer matrix and density from the polishing pad 10 to the bottom layer 16. The polishing surface 14 is used to polish or planarize a semiconductor substrate, such as a patterned integrated circuit wafer. Optionally, the polymer matrix is porous. If the polymer matrix is porous, it advantageously contains pores 18.

The holes 18 facilitate the delivery of CMP slurry, such as slurry and abrasive conditioning of the polishing layer 12, to form a consistent steady-state microstructure during polishing. This uniform microstructure includes openings 20 at the polishing surface 14. During polishing, the polishing layer 12 wears due to wear with the wafer and due to dressing (e.g., diamond dressing). When the polishing pad 10 is porous, the polishing layer 12 wears away constantly opening new pores at the polishing surface 14. A typical polishing layer 12 will have a microstructure created by opening micropores at the polishing surface 14.

Although the bottom surface 16 of the polishing pad 10 may be flat, it typically has a texture (fig. 4, 4A and 4B) for improving the adhesion of the porous subpads 45, 46 and 47. Such texture may be provided by abrading bottom surface 16 with an abrasive material, such as those used to flatten bottom surface 16 of polishing pad 10. Alternatively, such texture may be formed by scraping the polishing pad from the cast polymer cake. Scraping has the advantage of creating openings 22 in the bottom surface of the polishing pad 10.

Referring to fig. 2, under the polishing pad 10, a nonporous microlayer 30 is adhered to the bottom surface 16 of the polishing pad 10. The nonporous microlayer 30 conforms to the surface roughness of the bottom surface 16 for excellent adhesion. For example, the nonporous microlayer may accommodate the inner diameter of a scraped polymeric microelements having a weight average diameter of 10 to 50 μm. With this configuration, the surface roughness of the nonporous microlayer 30 is a mirror image of the surface roughness of the bottom surface 16 of the polishing pad 10. Preferably, the nonporous microlayer is a conformal coating that abuts the bottom surface 16 of the polishing pad 10. For example, the polymer matrix includes closed cell pores 18, the bottom surface 16 of the polishing pad 10 includes open cell pores 22, and the nonporous microlayer 30 adjoins the open cell pores 22 to at least partially fill the open cell pores of the bottom surface 16 of the polishing pad 10. Preferably, the nonporous microlayer fills a substantial portion of the open cells 22. Most preferably, the nonporous microlayer fills all of the open cells 22.

Referring to FIG. 3, under the polishing pad 10 and non-porous microlayer 30, dashed lines A-A separate the closed-cell cells 52, 54, 56, and 58 of the monolayer 50 from the non-porous microlayer 30. The closed cell cells 52, 54, 56, and 58 transfer compressive forces from the bottom surface 16 of the polishing layer 10 to the porous microlayer 30. This force transfer can reduce polishing edge effects and improve wafer throughput. Advantageously, at least half of the closed cells 52, 54, 56, and 58 of the monolayer 50 have a diameter that varies by less than fifty percent from the average diameter of the closed cells 52, 54, 56, and 58. Further, dashed lines B-B separate the single layer 50 from the multiple layers closing the apertures 52, 54, 56, and 58 (fig. 4, 4A, and 4B).

Referring to fig. 4, under the closed cells of polishing pad 10, non-porous microlayer 30, and single layer 50, multilayer 60 includes closed cells 62, 64, and 66, open cells (61A, 61B), (63A, 63B, and 63C), and (65A, 65B). Collectively, non-porous microlayer 30, monolayer 50, and multilayer 60 combine to form porous subpad 45. The thin non-porous microlayer 50 in combination with the single layer provides little rigidity to the subpad 45 to allow the subpad 45 to act as a single subpad. The perforated holes have the advantage of transmitting distributed compressive forces over a larger area by transporting pressurized gas between adjacent holes, such as holes 61A and 61B or holes 63A, 63B and 63C. Preferably, the inner surface of the interconnecting pores is hydrophobic to limit wicking during polishing. The hydrophobic open-celled pores 62, 64 and 66 provide the advantage of limiting wetting of the porous subpad for stable polishing. The closed cells 52, 54, 56, and 58 and the open cells (61A, 61B), (63A, 63B, and 63C) and (65A, 65B) of the multilayer 60 remain inflated throughout the polishing life of the polishing pad.

Referring to fig. 4A, under the closed cells of the polishing pad 10, the nonporous microlayer 30, and the single layer 50, the multiple layer 70 includes closed cells 72, 74, 76, and 78. Collectively, non-porous microlayer 30, monolayer 50, and multilayer 70 combine to form porous subpad 46. The closed cell pores have the advantage of limiting wetting of the porous subpad 46 for stable polishing. The closed cell pores 72, 74, 76 and 78 of the multilayer 70 remain inflated throughout the polishing life of the polishing pad.

Referring to fig. 4B, under the closed cells of the polishing pad 10, the nonporous microlayer 30, and the monolayer 50, the multilayer 80 includes open cells 82, 84, 86, and 88. Collectively, non-porous microlayer 30, monolayer 50, and multilayer 80 combine to form porous subpad 47. The perforated holes have the advantage of transmitting distributed compressive forces over a larger area by transporting pressurized gas between adjacent holes, such as holes 82, 84, 86 and 88. Preferably, the inner surface of the interconnecting pores is hydrophobic to limit wicking during polishing. The open cell pores 82, 84, 86 and 88 of the multi-layer 80 remain inflated throughout the polishing life of the polishing pad. Optionally, smaller holes (such as hole 83) may connect adjacent holes (such as holes 82 and 84).

Referring to fig. 1-4, 4A and 4B, the single closed cell layer 50 and the multiple layers 60, 70 and 80 combine to form a porous polymer network. Preferably, the nonporous microlayers have an average thickness that is less than fifty percent of the average diameter of the multilayered microholes within the polymer network to limit the stiffness of the subpads 45, 46, and 47. More preferably, the nonporous microlayer has an average thickness that is less than twenty-five percent of the average diameter of the multilayered microholes within the polymer network to limit the stiffness of subpads 45, 46, and 47.

Further, non-porous microlayer embodiments include non-porous microlayer 30, single closed cell layer 50, and mixed open and closed cell layers for porous subpad 45, closed cell layers for porous subpad 46, or open cell layers for porous subpad 47, respectively. Preferably, for closed cells and open cells, the closed cells are spherical and the open cells comprise oval cells. Porous subpads 45, 46, and 47 are adhered or affixed to bottom surface 16 of polishing pad 10. Examples of adhesion include chemical bonding and conformal coating. Preferably, the conformal coating adheres or secures the polishing pad 10 to the porous subpads 45, 46, and 47. Advantageously, all components of subpads 45, 46, and 47 have the same polymer composition. This improves the cohesion between microlayer 30, closed cell layer 50, and multilayers 60, 70, and 80 and allows subpads 45, 46, and 47 to act as a single compressible layer.

Referring to fig. 5, a polishing pad 110 has a polishing layer 112. The polishing layer 112 has a polishing surface 114 and is formed of a polymer matrix. The polishing pad 110 also has a bottom surface 116 that defines the polishing pad 110. Advantageously, the polishing pad 110 has a uniform polymer matrix and density from the polishing surface 114 to the bottom layer 116. Polishing surface 114 is used to polish or planarize a semiconductor substrate, such as a patterned integrated circuit wafer. Optionally, the polymer matrix is porous. If the polymer matrix is porous, it advantageously contains pores 118.

The holes 118 facilitate the delivery of CMP slurry, such as slurry and abrasive conditioning of the polishing layer 112, to form a consistent steady-state microstructure during polishing. This uniform microstructure includes openings 120 at the polishing surface 114. During polishing, the polishing layer 112 wears due to wear with the wafer and due to dressing (e.g., diamond dressing). When the polishing pad 110 is porous, the polishing layer 112 wears away constantly opening new pores at the polishing surface 114. A typical polishing layer 112 will have a microstructure created by opening micropores at the polishing surface 114.

Although the bottom surface 116 of the polishing pad 110 can be flat, it typically has a texture for improving the adhesion of the non-porous layer 130. The non-porous layer 130 fills the bottom layer 116 to form a conformal layer. Such texture may be formed by abrading the bottom surface 116 with an abrasive material, such as those used to flatten the bottom surface 116 of the polishing pad 110. Alternatively, such texture may be formed by scraping the polishing pad from the cast polymer cake. Scraping has the advantage of creating openings 122 in the bottom surface of the polishing pad 110. With this configuration, the surface roughness of the nonporous microlayer 130 is a mirror image of the surface roughness of the bottom surface 116 of the polishing pad 110. Preferably, the nonporous microlayer is a conformal coating that abuts the bottom surface 116 of the polishing pad 110. For example, the polymer matrix includes closed cell pores 118, the bottom surface 116 of the polishing pad 110 includes open cell pores 122, and the nonporous microlayer 130 adjoins the open cell pores 122 to at least partially fill the open cell pores of the bottom surface 116 of the polishing pad 110. Preferably, the nonporous microlayer fills a substantial portion of the open micropores 122. Most preferably, the nonporous microlayer fills all of the open micropores 122. The non-porous layer 130 extends from the bottom surface 116 of the polishing pad 110 to the dashed line C-C.

Referring to fig. 6, under the polishing pad 110 and the non-porous layer 130, the non-porous layer 130 typically has a thickness greater than the average pore diameter of the multiple layers 140. Advantageously, non-porous layer 130 has a thickness at least twice (two percent) the thickness of the average pore diameter of multilayer 140. The non-porous layer 130 secures the polishing pad 110 to the porous subpad 125. The non-porous layer has a polymer matrix and forms a micron-sized negative impression of the bottom surface of the polishing pad 110; and such negative impression of the non-porous layer abuts the bottom of the polishing pad 110. The non-porous layer 130 adds significant rigidity to the polishing pad 110. Thus, the non-porous layer 130 in combination with the porous multilayer 140 acts as a two-layer subpad.

Multilayer 140 includes closed cells 142 and 144, open cells (141A, 141B) and (143A, 143B). Apertured holes such as (141A, 141B) and (143A, 143B) have the advantage of transmitting and distributing compressive forces over a larger area by transporting pressurized gas between adjacent holes such as holes (141A, 141B) or (143A, 143B). The nonporous layer 130 and the multiple layers 140 combine to form the porous subpad 125. Preferably, the inner surface of the interconnecting pores is hydrophobic to limit wicking during polishing. The closed cell cells 142, 144, and 146 provide the advantage of limiting wetting of the porous subpad 125 for stable polishing. The multi-layer 140 closed cell, open cell, or a mixture of closed cell and open cell pores has the same polymer matrix and greater flexibility than the non-porous layer, and the polishing pad has a porosity. In addition, the porous subpad 125 has a porosity greater than the porosity of the polishing pad 110.

Referring to fig. 6A, under the polishing pad 110 and the non-porous layer 130, the multilayer 140 includes closed cells 150, 152, 154, 156, and 158. The nonporous layer 130 and the multiple layers 140 combine to form the porous subpad 126. The closed cell cells 150, 152, 154, 156, and 158 have the advantage of limiting wetting of the porous subpad 126 for stable polishing.

Referring to fig. 6B, under the polishing pad 110 and the non-porous layer 130, the multilayer 140 includes openings 160, 162, 164, 166, and 168. Non-porous layer 130 and multi-layer 140 combine to form porous subpad 127. The perforated holes 160, 162, 164, 166 and 168 have the advantage of transmitting distributed compressive forces over a larger area by transporting pressurized gas between adjacent holes (such as holes 160, 162, 164, 166 and 168). Preferably, the inner surface of the interconnecting pores is hydrophobic to limit wicking during polishing. Optionally, smaller holes (such as holes 163 and 167) may connect adjacent holes, such as hole 162 and hole 164 and hole 166 and hole 168.

Fig. 5, 6A and 6B are sequentially combined to illustrate a two-layer subpad embodiment of the present invention. Two layer embodiments include a non-porous layer 130, a mixed open and closed cell layer for porous subpad 125, a closed cell layer for porous subpad 126, or an open cell layer for porous subpad 127, respectively. Porous subpads 125, 126, and 127 are adhered or affixed to bottom surface 116 of polishing pad 110. Examples of adhesion include chemical bonding and conformal coating. Preferably, the conformal coating adheres or secures the polishing pad 110 to the porous subpads 125, 126, and 127.

Referring to fig. 7 and 7A, subpad 200 has concentric recessed rings 202 and 204. During CMP polishing, the top or polishing layer 210 combines to establish wafer center and edge polishing profiles. The recessed rings 202 and 204 represent macro-features that extend into the subpad 200 of the polishing pad 206 to adjust the polishing profile of the chemical mechanical polishing pad 206. To increase deflection, the macro-features 202 and 204 extend partially into the polishing layer 210. For example, when the edge profile is too fast or too slow, then the percentage of acceptable chips on the wafer or wafer yield is significantly reduced. The width and depth of the concentric rings 202 and 204 are adjusted to control deflection near the center and periphery to increase wafer throughput. The macro-features may be of any shape, but preferably they are concentric rings.

Advantageously, the polishing pad 206 has a porosity and the porous subpad 200 has a porosity that is greater than the porosity of the polishing pad 206. The greater porosity of subpad 200 provides greater deflection of polishing pad 206 to increase the contact area with the wafer (not seen) for more efficient polishing. While the subpads of fig. 4, 4A, 4B, 6A, and 6B may already improve wafer yield, the back side concentric recessed rings 202 and 204 may further improve edge effects and wafer yield.

The schematic diagrams of these figures show how the center polishing profile and the edge polishing profile are adjusted. Specifically, land areas 212 between grooves 214 of polishing layer 210 have increased flexibility and exert less pressure on the wafer to reduce the polishing rate in localized areas. The location and size of these backside recesses control the amount of deflection of the corrective polishing profile.

Referring to fig. 8 and 8A, polishing pad 300 includes concentric circular grooves 302. The polishing surface 303 is adjacent to the circular recess 302. The grooves 302 extend from adjacent centers 304 to a periphery 306. The circular grooves 302 extend into the polishing layer 308 to facilitate slurry transfer. Because the polishing surface 303 of the polishing layer 308 interacts directly with the wafer surface, adjusting the compressibility of the polishing layer 308 has a direct effect on the removal rate.

The compressibility of polishing pad 300 depends on the ratio of the thickness of polishing layer 308 to the thickness of subpad 310. Further, increasing the number, depth, or width of the annular groove cavities 312 and 314 may increase the compressibility of the polishing layer 308 above and adjacent to the annular groove cavities 312 and 314. Annular groove cavities 312 and 314 do not penetrate polishing layer 308 to prevent slurry leakage into the subpad. Most advantageously, the annular groove cavities 312 and 314 do not penetrate the circular groove 302 or the polishing layer 303 to prevent slurry leakage into the subpad. Annular groove cavities 312 and 314 allow for variable compressibility by varying the thickness ratio in different annular regions and varying the thickness ratio by different amounts on polishing pad 300. This adjustment of the compressibility ratio allows the end user to reduce polishing rate variability resulting from the CMP process.

Most advantageously, the annular groove cavity is adjacent to the perimeter 306 to reduce polishing rate edge effects. This occurs by increasing the compressibility of the polishing layer to reduce pressure on the wafer from around the periphery 306 of the polishing pad 300. The reduced pressure near the periphery 306 then counteracts edge flash polishing that can occur from increased pad pressure near the periphery 306 of the polishing pad. Alternatively, the design may have an annular cavity 312 or 314 that begins at the center 304 to a location spaced from the periphery 306. This design increases the relative pressure on the wafer near the perimeter 306 to counteract edge slow polishing.

Further, the annular groove cavity 312 may have a gradual transition, wherein the side walls 313 slope inwardly toward the annular groove cavity 312. The annular groove cavity 314 has a stepped transition through the use of vertical sidewalls 315. These designs provide the advantage of controlling and adjusting the compressibility transitions on the polishing surface 303 of the polishing layer 308 to reduce polishing removal rate variation and flatten the removal rate profile on the wafer.

Referring to fig. 9 and 9A, polishing pad 400 includes concentric circular grooves 402. The polishing surface 403 is adjacent to the circular recess 402. The grooves 402 extend from adjacent centers 404 to a perimeter 406. These grooves 402 extend into the polishing layer 408 to facilitate slurry transfer. The compressibility of polishing pad 400 depends on the ratio of the thickness of polishing layer 408 to the thickness of subpad 410. Further, increasing the number, depth, or width of the annular groove cavities 412 and 414 may increase the compressibility of the polishing layer 408 above and adjacent to the annular groove cavities 412 and 414. Thus, annular groove cavities 414 and 420 allow for variable compressibility by varying the thickness ratio in different annular regions and varying the thickness ratio by different amounts on polishing pad 400. This adjustment of the compressibility ratio allows the end user to reduce polishing rate variability resulting from the CMP process.

Most advantageously, the annular groove cavity is adjacent to the perimeter 406 to reduce polishing rate edge effects. This occurs by increasing the compressibility of the polishing layer to reduce pressure on the wafer from near the periphery 406 of the polishing pad 400. The reduced pressure near the periphery 406 then counteracts edge flash polishing that can occur from the increased pad pressure near the periphery 406 of the polishing pad. Alternatively, the design may have an annular groove cavity 414 or 420 that begins at the center 404 to a location spaced from the periphery 406. This design increases the relative pressure on the wafer near the perimeter 406 to counteract edge slow polishing.

In addition, the annular groove cavity 420 may have a tab shape to improve adhesion of the subpad 410 to the polishing layer 308. Increasing the number of annular tab shaped groove cavities 420 increases adhesion to the polishing layer 408. Alternatively, a larger tab-shaped recess facilitates a larger polishing profile correction. These designs provide the advantage of controlling and adjusting the compressibility transitions on the polishing surface 403 of the polishing layer 408 itself to reduce polishing removal rate variations and flatten the removal rate profile on the wafer.

The polishing pad has a polishing pad formed from a polymer matrix. These polymers may be thermoplastic polymers or thermosetting polymers. Typically, thermoset polymers provide the most reliable polishing characteristics. Suitable polymers include polyurethanes, polycarbonates, acrylics, polyolefins, polyesters, polyacrylics, and copolymers thereof. Most advantageously, the polymer is polyurethane. For the purposes of this specification, the term polyurethane includes polymeric polyurethanes including at least one selected from the group consisting of polyether ureas, polyisocyanurates, polyurethanes, polyureas, polyurethaneureas, copolymers thereof, and mixtures thereof.

The polishing pad can be porous or non-porous. Preferably, the polishing layer has roughness with sufficient rigidity for planarizing the semiconductor substrate. The polishing pad can be closed cell or open cell. Most advantageously, the polishing pad is closed cell. Fluid-filled polymeric microspheres can provide an effective means for creating closed cell porosity. These microspheres help create texture or roughness, distribution of slurry, and transportation of slurry.

The porous subpad is adhered to the bottom surface of the polishing pad with a non-porous microlayer to secure the polishing pad to the porous subpad. The nonporous microlayer is a conformal coating on the bottom surface adjacent to the microlayer. Abutment with the bottom surface is particularly important when the bottom surface of the polishing pad is non-linear. Examples of non-linear bottom surfaces include open cells, such as cut or shaved closed cells. The microlayers can adhere to the polishing pad by following the texture of the bottom surface of the polishing pad, acting as an adhesive, or otherwise bonding to the polishing pad.

Since the microlayer is non-porous, it does not have great compressibility. But since the microlayer is thin, it is flexible and can accommodate the bending of the polishing pad. This bending of the nonporous microlayer is critical to not increase the stiffness of the polishing pad to the point where the polishing pad may no longer conform to the wafer during polishing. Advantageously, the nonporous microlayer has an average thickness that is less than fifty percent of the average diameter of closed cells within the polymer network. Most advantageously, the nonporous microlayer has an average thickness of less than fifty percent of the average diameter of closed cells within the polymer network.

A polymer network comprising a monolayer of closed cell micropores is adjacent to the nonporous microlayer. This polymer network combines with closed cell micropores to provide a transition from a flexible, non-porous layer to a compressible layer.

The compressible layer is a plurality of layers of closed or open cells. Advantageously, the multilayer is a mixture of open and closed cells. This layer is adjacent to the pores of the single layer closed cells and provides most of the compressibility of the subpad. In particular, controlling thickness, modulus, density, and pore size represent the primary factors in the compressibility of the subpad. The pores may be open pore, closed pore, or a combination of closed and open pore, wherein less than ten volume percent of the pores are open. Most advantageously, the micropores are a combination of open and closed cell micropores. Open cell pores provide the advantage of distributing the load over a larger area. Closed cell microwells provide the advantage of limiting wicking of subpad with slurry during polishing.

The multiple layers of closed or open cells are inflated and remain inflated throughout the polishing life of the polishing pad. This is important to prevent the slurry from wicking into the subpad. Wicking of slurry into the subpad typically has an adverse effect on the compressibility of the subpad and alters the performance from the first wafer to the last wafer during polishing. For these reasons, therefore, it is critical that the subpad not be filled with slurry during polishing. Typically, these micropores are spherical or non-spherical in shape, such as those having spheres of elongated axes or ovals with symmetrical ends. Advantageously, the microwells are a combination of spherical and oval microwells.

The polishing section can comprise any of the polymer matrix materials commonly used in polishing pads. The polishing section may comprise a thermoplastic or thermosetting polymer. Among the polymeric materials that may be used in the base pad or polishing section, examples of polymers that may be used in the polishing section include polycarbonates, polysulfones, nylons, epoxies, polyethers, polyesters, polystyrenes, acrylic polymers, polymethyl methacrylates, polyvinylchlorides, polyvinylfluorides, polyethylenes, polypropylenes, polybutadienes, polyethylenimines, polyurethanes, polyethersulfones, polyamides, polyetherimides, polyketones, epoxies, silicones, copolymers thereof (such as polyether-polyester copolymers), and combinations or blends thereof. The polymer may be polyurethane.

The Young's modulus of the polished section may be at least 2, at least 2.5, at least 5, at least 10, or at least 50MPa up to 900, up to 700, up to 600, up to 500, up to 400, up to 300, or up to 200MPa according to ASTM D412-16. The polishing section may be opaque to the signal used for endpoint detection.

The polishing section may also comprise other additives, such as, in particular, hollow micro-components, in particular, flexible hollow polymeric micro-components, for example, polymeric microspheres. For example, the plurality of microelements can be uniformly dispersed throughout the polishing pad. The plurality of microelements may be simply pores in a matrix (e.g., entrapped gas bubbles), or may be hollow core polymeric material, liquid filled hollow core polymeric material, water soluble material, or insoluble phase material (e.g., mineral oil). The plurality of microelements provide porosity to the polishing element, for example, when the microelements are selected from the group consisting of entrapped air bubbles and hollow polymeric materials uniformly distributed throughout the polishing pad. The microelements are advantageously microspheres having an average diameter of at most 150 microns or at most 50 microns, while having a diameter of at least 10 microns. The weight average diameter may be measured using laser diffraction, such as small angle laser light scattering (LALLS). The plurality of microelements may comprise polymeric microspheres (e.g., from Noron (Nouryon)) having a shell wall of polyacrylonitrile or a polyacrylonitrile copolymerMicrospheres). The plurality of microelements can be incorporated into the polishing pad in an amount of 0 volume percent, or at least 5 volume percent, or at least 10 volume percent, at most 50 volume percent, at most 45 volume percent, at most 40 volume percent, or at most 35 volume percent. When the micro-component provides porosity, the porosity of the polished portion can be 0 to 50, 5 to 45, or 10 to 35 percent porosity. The percentage of porosity can be determined by dividing the difference between the specific gravity of the unfilled polishing pad and the specific gravity of the micro-element-containing polishing pad by the specific gravity of the unfilled polishing pad. Alternatively, the percent porosity is determined by dividing the density of the polishing pad by the weighted average density of the portion of the polishing pad.

The polished portion can have a density of 0.4 to 1.15 or 0.7 to 1.0g/cm ³ as measured according to ASTM D1622 (2014).

The top pad or polishing pad can have a shore D hardness of 28 to 75 as measured according to ASTM D2240 (2015). To improve accuracy, it is important that the stack uses a stack of at least four high 2.54cm square samples.

The polishing pad can have an average thickness of 20 to 150 mils, 30 to 125 mils, 40 to 120 mils, or 50 to 100 mils (0.5-4, 0.7-3, 1-3, or 1.3-2.5 mm).

The subpad can be made from foamed and cast polymers, wherein the thickness of the nonporous microlayer or nonporous layer is determined by the viscosity and porosity of the polymer during casting or other known techniques for forming polymeric foam or porous materials. Advantageously, the subpad uses a spray forming technique in which the droplets form pores and the exotherm in the polymer controls the thickness of the non-porous microlayer or layers. Casting or spraying the subpad provides the advantage of avoiding the use of hot melt adhesives or pressure sensitive adhesives to secure the subpad to the polishing layer. The subpad may also have a total thickness of at least 0.5 or at least 1 mm. The subpad may have a total thickness of no more than 5, no more than 3, or no more than 2 mm.

The top pad or polishing pad can comprise any material known for use as a polishing layer for a polishing pad. For example, the material may comprise a polymer, a blend of polymers, or a composite of a polymeric material with other materials, such as ceramic, glass, metal, or stone. Polymers and polymer composites may be used as the top pad. Examples of such composite materials include polymers filled with carbon or inorganic fillers, and fiber mats such as glass or carbon fibers impregnated with polymers. The top pad may be made of a material having one or more of the following properties: a young's modulus in the range of at least 2, at least 2.5, at least 5, at least 10, or at least 50MPa up to 900, up to 700, up to 600, up to 500, up to 400, up to 300, or up to 200MPa as determined, for example, by astm d 412-16; a poisson's ratio of at least 0.05, at least 0.08, or at least 0.1 up to 0.6 or up to 0.5 as determined, for example, by ASTM E132; a density of at least 0.4 or at least 0.5 up to 1.7, up to 1.5, or up to 1.3 grams per cubic centimeter (g/cm 3).

Examples of such polymeric materials that may be used in the top pad or polishing section include polycarbonates, polysulfones, nylons, epoxies, polyethers, polyesters, polystyrenes, acrylic polymers, polymethyl methacrylates, polyvinylchlorides, polyvinylfluorides, polyethylenes, polypropylenes, polybutadienes, polyethyleneimines, polyurethanes, polyethersulfones, polyamides, polyetherimides, polyketones, epoxies, silicones, copolymers thereof (such as polyether-polyester copolymers), or combinations or blends thereof.

The polymer may be polyurethane. The polyurethane may be used alone or may be a matrix of carbon or inorganic fillers and fiber mats such as glass or carbon fibers.

For the purposes of this specification, a "polyurethane" is a product derived from difunctional or polyfunctional isocyanates, such as polyether urea, polyisocyanurate, polyurethane, polyurea, polyurethane urea, copolymers thereof and mixtures thereof. The CMP polishing pad according to the present invention can be manufactured by a method comprising: providing an isocyanate-terminated urethane prepolymer; separately providing a curative component; and mixing the isocyanate-terminated urethane prepolymer and the curative component to form a combination, and then reacting the combination to form the product. The top pad or polishing pad may be formed by scraping a cast polyurethane cake to a desired thickness. Optionally, preheating the cake mold with IR radiation, induced current or direct current may reduce product variability when casting the porous polyurethane matrix. Optionally, thermoplastic or thermosetting polymers may be used. The polymer may be a cross-linked thermosetting polymer.

When polyurethane is used in the top pad or polishing pad, it can be the reaction product of a polyfunctional isocyanate and a polyol. For example, polyisocyanate-terminated urethane prepolymers may be used. The polyfunctional isocyanate used to form the polishing pad of the chemical mechanical polishing pad of the invention may be selected from the group consisting of: aliphatic polyfunctional isocyanates, aromatic polyfunctional isocyanates, and mixtures thereof. For example, the multifunctional isocyanate used to form the polishing pad of the chemical mechanical polishing pad of the invention can be a diisocyanate selected from the group consisting of: 2,4 toluene diisocyanate; 2,6 toluene diisocyanate; 4,4' -diphenylmethane diisocyanate; naphthalene 1,5 diisocyanate; toluidine diisocyanate; para-phenylene diisocyanate; xylylene diisocyanate; isophorone diisocyanate; hexamethylene diisocyanate; 4,4' -dicyclohexylmethane diisocyanate; cyclohexane diisocyanate; and mixtures thereof. The polyfunctional isocyanate may be an isocyanate-terminated urethane prepolymer formed by the reaction of a diisocyanate with a prepolymer polyol. The isocyanate-terminated urethane prepolymer may have 2 to 12wt.%, 2 to 10wt.%, 4-8wt.%, or 5 to 7wt.% unreacted isocyanate (NCO) groups. The prepolymer polyol used to form the polyfunctional isocyanate-terminated urethane prepolymer may be selected from the group consisting of: diols, polyols, polyol diols, copolymers thereof, and mixtures thereof. For example, the prepolymer polyol may be selected from the group consisting of: polyether polyols (e.g., poly (oxytetramethylene) glycol, poly (oxypropylene) glycol, and mixtures thereof); a polycarbonate polyol; a polyester polyol; polycaprolactone polyol; mixtures thereof; and mixtures thereof with one or more low molecular weight polyols selected from the group consisting of: ethylene glycol; 1,2 propylene glycol; 1,3 propylene glycol; 1,2 butanediol; 1,3 butanediol; 2 methyl 1,3 propanediol; 1,4 butanediol; neopentyl glycol; 1,5 pentanediol; 3 methyl 1,5 pentanediol; 1,6 hexanediol; diethylene glycol; dipropylene glycol; tripropylene glycol. For example, the prepolymer polyol may be selected from the group consisting of: polytetramethylene ether glycol (PTMEG); ester-based polyols (e.g., ethylene glycol adipate, butylene glycol adipate); polypropylene ether glycol (PPG); polycaprolactone polyol; copolymers thereof; and mixtures thereof. For example, the prepolymer polyol may be selected from the group consisting of: PTMEG and PPG. When the prepolymer polyol is PTMEG, the unreacted isocyanate (NCO) concentration of the isocyanate-terminated urethane prepolymer may be 4 to 12wt.% (more preferably 6 to 10wt.%; most preferably 8 to 10 wt.%). Examples of commercially available PTMEG-based isocyanate-terminated urethane prepolymers includePrepolymers (available from american co company (COIM USA, inc.) such as PET 80A, PET 85A, PET 90A, PET 93A, PET A, PET 3560D, PET 70D, PET D); /(I)Prepolymers (available from kopoly (Chemtura), such as LF 800A、LF 900A、LF 910A、LF 930A、LF 931A、LF 939A、LF 950A、LF 952A、LF 600D、LF 601D、LF 650D、LF 667、LF 700D、LF750D、LF751D、LF752D、LF753D and L325); /(I)Prepolymers (available from anderson development company (Anderson Development Company), such as 70APLF, 80APLF, 85APLF, 90APLF, 95APLF, 60DPLF, 70APLF, 75 APLF). When the prepolymer polyol is PPG, the unreacted isocyanate (NCO) concentration of the isocyanate-terminated urethane prepolymer may be 3 to 9wt.% (more preferably 4 to 8wt.%; most preferably 5 to 6 wt.%). Examples of commercially available PPG-based isocyanate-terminated urethane prepolymers include/>Prepolymers (available from american co such as PPT 80A, PPT 90A, PPT 95A, PPT 3565D, PPT D); /(I)Prepolymers (available from koku poly, such as LFG 963A, LFG 964A, LFG D); />Prepolymers (available from anderson development, such as 8000APLF, 9500APLF, 6500DPLF, 7501 DPLF). The isocyanate-terminated urethane prepolymer may be a low free isocyanate-terminated urethane prepolymer having a free Toluene Diisocyanate (TDI) monomer content of less than 0.1 wt.%. Isocyanate-terminated urethane prepolymers based on non-TDI may also be used. For example, isocyanate-terminated urethane prepolymers include those formed by reacting 4,4' diphenylmethane diisocyanate (MDI) with a polyol such as polytetramethylene glycol (PTMEG), with optional diols such as 1,4 Butanediol (BDO) being acceptable. When such isocyanate-terminated urethane prepolymers are used, the concentration of unreacted isocyanate (NCO) is preferably 3 to 10wt.% (more preferably 4 to 10wt.%, most preferably 5 to 10 wt.%). Examples of commercially available isocyanate-terminated urethane prepolymers in this category include/>Prepolymers (available from american co company such as 27 85a, 27 90a, 27 95 a); /(I)Prepolymers (available from anderson development, such as IE75AP, IE80AP, IE 85AP, IE90AP, IE95AP, IE98 AP); />Prepolymers (available from koku poly, such as B625, B635, B821).

The polishing pad of the invention in its final form can include texture incorporated on its upper surface in one or more dimensions. These can be classified as either macroscopic or microscopic depending on their size. Common types of macroscopic textures used for CMP to control hydrodynamic response and slurry transport include, but are not limited to, many configurations and designs of grooves, such as annular, radial, and intersecting lines. These may be formed as uniform flakes by a machining process or may be formed directly on the pad surface by a net forming process. A common type of micro-texture is a finer scale feature that produces a large number of surface asperities that are points of contact with the substrate wafer where polishing occurs. Common types of micro-textures include, but are not limited to, textures formed by grinding with an array of hard particles such as diamond (commonly referred to as pad dressing), before, during, or after use, and micro-textures formed during the pad manufacturing process.

The polishing pad of the invention can be adapted to engage a platen of a chemical mechanical polisher. The polishing pad can be secured to a platen of a polishing machine. The polishing pad can be secured to the platen using at least one of a pressure sensitive adhesive and a vacuum.

The CMP pads of the present invention can be manufactured by a variety of methods that are compatible with the characteristics of the pad polymer being used. These methods include mixing and casting the ingredients described above into a mold, annealing, and cutting into pieces of the desired thickness. Alternatively, they may be manufactured in a more accurate net shape form. The manufacturing method comprises the following steps: 1. thermoset injection molding (commonly referred to as "reaction injection molding" or "RIM"); 2. thermoplastic or thermosetting injection blow molding; 3. compression molding; or any similar type of method in which the flowable material is positioned and cured to create at least a portion of the macro-texture or micro-texture of the pad. For example, the molded polishing pad can comprise the following: 1. forcing the flowable material into or onto the structure or substrate; 2. the structure or substrate may impart texture to the surface of the material as it cures; and 3. Thereafter separating the structure or substrate from the cured material.

Method of

Polishing pads as disclosed herein can be used to polish a substrate. For example, a polishing method can comprise providing a substrate to be polished, and then polishing using the pads disclosed herein. The substrate may be any substrate that requires polishing or planarization. Examples of such substrates include magnetic substrates, optical substrates, and semiconductor substrates. A specific example is a pre-metal dielectric stack. The particular material to be polished on the substrate may be a silicon oxide layer. The method may be part of a front-end-of-line or back-end-of-line processing of the integrated circuit. For example, the process may be used to remove undesirable surface topography and surface defects such as rough surfaces, agglomerated materials, lattice damage, scratches, and contaminated layers or materials. Further, in a damascene process, material is deposited to fill recessed areas created by one or more of photolithography, patterned etching, and metallization. Some steps may be inaccurate, for example, the recess may be overfilled. The methods disclosed herein may be used to remove material outside the recess. The process may be chemical mechanical planarization or chemical mechanical polishing, both of which may be referred to as CMP. The carrier can hold a substrate to be polished, such as a semiconductor wafer (with or without a layer formed by photolithography and metallization), in contact with the polishing elements of the polishing pad. A slurry or other polishing medium can be dispensed into the gap between the substrate and the polishing pad. The polishing pad and the substrate are moved, e.g., rotated, relative to one another. The polishing pad is typically positioned below the substrate to be polished. The polishing pad can be rotated. The substrate to be polished can also be moved, for example, on a polishing track, such as a ring shape. The relative movement causes the polishing pad to approach and contact the surface of the substrate.

The pressure of the platen may be 1 to 5, 1.5 to 4.5, or 2 to 4 pounds per square inch (psi) (about 6-35, 10-30, or 13 to 28 kilopascals (KPa)). The speed of the platen may be about 40 to 100, or 50-90rpm. The amount of slurry added may be, for example, 50 to 500 ml/min. The pH of the slurry during polishing can be acidic, neutral or basic.

For example, the method may include: providing a chemical mechanical polishing apparatus having a platen or carrier assembly; providing at least one substrate to be polished; providing a chemical mechanical polishing pad as disclosed herein; mounting a chemical mechanical polishing pad to the platen; optionally, providing a polishing medium (e.g., an abrasive-containing slurry and/or a non-abrasive-containing reactive liquid composition) at an interface between the polishing portion of the chemical mechanical polishing pad and the substrate; dynamic contact is made between the polishing portion of the polishing pad and the substrate, wherein at least some of the material is removed from the substrate. The carrier assembly can provide a controllable pressure between a substrate (e.g., wafer) to be polished and a polishing pad. The polishing medium can be dispensed onto the polishing pad and allowed to wick into the gap between the wafer and the polishing layer. The polishing medium can comprise water, a pH adjustor, and optionally (but not limited to) one or more of the following: abrasive particles, oxidizing agents, inhibitors, antimicrobial agents, soluble polymers, and salts. The abrasive particles may be oxide, metal, ceramic, or other suitably hard material. Typical abrasive particles are colloidal silica, fumed silica, ceria, and alumina. The polishing pad and the substrate can rotate relative to one another. As the polishing pad rotates beneath the substrate, the substrate can sweep through a typically annular polishing track or polishing zone, wherein the surface of the wafer directly faces the polishing portion of the polishing pad. The wafer surface is polished and planarized by chemical and mechanical action of the polishing layer and polishing media on the surface. Optionally, the polishing surface of the polishing pad may be dressed with an abrasive dresser prior to starting polishing.

All subpads of the present invention are produced by spray foaming with polymer exotherms or heat of reaction to control the thickness of the non-porous microlayers or layers.

Example 1

Polishing results

And (3) sizing: planar-Solution CSL9044C 1:9 dilution

Tool configuration: EBARA FREX-300X with GX head

A disk: kinik PDA31G-3N

Top pad: polymeric microsphere filled polyurethane (65 mil/1.6 mm), volume porosity of 25% to 30%, shore D hardness of 40 to 50, circular groove width of 20 mil (0.5 mm), depth of 30 mil (0.8 mm) and spacing of 70 mil (1.8 mm)

Wafer: block Cu wafer

The wafer edge profile range is calculated to be 142mm to 147mm from the wafer center

Low downforce polishing conditions= (100 hPa-1.4 psi)

High downforce polishing conditions= (200 hPa-2.9 psi)

Comparative a and B are foamed porous polyurethane polishing subpads having interconnected pores (with random pore size distribution).

Subpads 1 to 6 are porous subpads having a single layer of pores and then a random layer of closed and open pores.

Low down force

These low pressure data demonstrate that when the nonporous microlayer subpad of the present invention has a thickness equal to or greater than conventional subpads, it provides improved edge coverage at low pressures with similar removal rates. Furthermore, when the nonporous microlayer subpad of the present invention has a much smaller thickness, it improves edge coverage at low downforce with increased removal rates.

High down force

These data demonstrate that the nonporous microlayer subpad of the present invention provides improved edge coverage at high downforce pressures with similar removal rates when it has a thickness less than, equal to, or greater than conventional subpads. Furthermore, when the nonporous microlayer subpad of the present invention has a reduced thickness, it improves the removal rate with a substantial improvement in edge margin.

Example 2

65 Mil/1.6 mm sub-pad for density effect-bulk Cu process

Tool configuration: EBARA FREX-300X with GX head

And (3) sizing: planar-Solution CSL9044C 1:9 dilution

A disk: kinik PDA31G-3N

Wafer: block Cu wafer

Low downforce polishing conditions (100 hPa-1.4 psi)

High downforce polishing conditions (200 hPa-2.9 psi)

Comparative C and D are foamed cellular polyurethane polishing subpads having interconnected pores (with random pore size distribution). Comparative examples E and F show the structure of subpads 9 to 11 without a non-porous layer.

Subpads 9 to 12 are porous subpads which have no non-porous layer or a non-porous layer having a thickness of 84 or 73 μm, no single layer of pores and then a random pore layer.

Low down force

These data demonstrate that the nonporous layer subpad of the present invention provides improved edge coverage at low downforce with similar removal rates when it has the same and higher density than conventional subpads. The effect on edge rate is particularly pronounced for non-porous layer subpads having the same density.

High down force

Although comparative F has a desired reduction over the edge margin, it experiences some process instability during the trimming process due to subpad compression. These data indicate that when the nonporous layer subpad of the present invention has a lower density than, the same as, and higher than conventional subpads, the subpad provides improved edge coverage at high downforce pressures with similar removal rates. The effect on edge rate is particularly pronounced for non-porous layer subpads having the same or greater density.

Example 3:

ILD oxide process

Tool configuration: AMAT Reflexion with Contourr header

And (3) sizing: klebosol 1730

A disk: saesol AK 45A

Top pad: IC1010 polyurethane pad with polymer microsphere (80 mil/2.0 mm)

Wafer: blanket TEOS

Head pressure: 3psi (20.7 kPa)

Comparative G is a SUBA IV ^TM compressible polyurethane impregnated nonwoven felt.

Subpad 15 is a porous subpad having a single layer of pores and then a random pore layer.

These data demonstrate that when the nonporous microlayer subpad of the present invention has a greater thickness than conventional subpads, it provides improved edge coverage at high downforce pressures with lower removal rates.

Example 4

Ultra high oxide rate process

Tool configuration: AMAT Reflexion LK with Contourr header

And (3) sizing: asahi CES330XD4 (1:4 dilution)

A disk: KINIK PYRADIA A

Top pad: IK4250UH polyurethane pad with polymer microsphere (80 mil/2.0 mm)

Wafer: TEOS blanket type chip

Head pressure: 3psi (20.7 kPa)

Comparative H is a foamed cellular polyurethane polishing subpad having interconnected pores (with random pore size distribution).

Subpads 16 and 17 are porous subpads having a single layer of pores and then a random pore layer.

These data demonstrate that when the nonporous microlayer subpad of the present invention has a greater thickness than conventional subpads, it provides improved edge coverage at high downforce pressures with higher removal rates.

Example 5

Polishing results

And (3) sizing: planar-Solution CSL9044C 1:9 dilution

Tool configuration: EBARA FREX-300X with GX head

A disk: kinik PDA31G-3N

Top pad: the circular grooves of the foamed polyurethane (65 mil/1.6 mm) had a width of 20 mils (0.5 mm), a depth of 30 mils (0.8 mm) and a spacing of 70 mils (1.8 mm)

Wafer: block Cu wafer

Low downforce polishing conditions= (100 hPa-1.4 psi)

High downforce polishing conditions= (200 hPa-2.9 psi)

Comparative G and H are foamed porous polyurethane polishing subpads having interconnected pores (with random pore size distribution).

Subpads 18 and 19 are porous subpads having macroscopic features extending into the polishing pad, having a single layer of pores and then a random pore layer.

Low down force

These data demonstrate that when the nonporous microlayer subpad of the present invention has a thickness equal to that of a conventional subpad, it provides improved edge coverage at low downforce with or without macroscopic features, with similar removal rates. The impact on edge rate is particularly pronounced for nonporous microlayer subpads having a range of macroscopic features.

High down force

These data demonstrate that when the nonporous microlayer subpad of the present invention has a thickness equal to that of a conventional subpad, it provides improved edge coverage under high downforce with or without macroscopic features, with similar removal rates. The impact on edge rate is particularly pronounced for nonporous microlayer subpads having a range of macroscopic features.

The nonporous microlayers, the single closed cell layers, and the multiple layers all combine to control and reduce edge effects. In particular, they combine to form a polishing layer that functions as a two-component system, wherein the polishing layer works in combination with the integral porous subpad to limit or reduce edge effects. In addition, this subpad design improves uniformity of product performance. Finally, the integration of non-porous microlayers into the roughened surface of the polishing layer serves to create an effective adhesion between the polishing layer and the subpad that does not separate during harsh polishing conditions.

Claims

1. A chemical mechanical polishing pad comprising:

A polishing pad having a polymer matrix for polishing a polishing surface and a bottom surface of at least one of a semiconductor, magnetic, and optical substrate;

A porous subpad adhered to the bottom surface of the polishing pad, the porous subpad comprising:

A non-porous microlayer for securing the polishing pad to the porous subpad, the non-porous microlayer being flexible and forming a micron-sized conformal coating on the bottom surface of the polishing pad and the non-porous layer being contiguous with the bottom surface of the polishing pad;

A porous polymer network, the porous polymer network comprising:

i) A single layer of closed cell pores adjacent to the nonporous microlayer for transferring compressive forces from the bottom surface of the polishing pad to the porous subpad; and

Ii) a plurality of closed cells, open cells, or a mixture of closed cells and open cells adjacent to the single-layer closed cells, wherein the plurality of closed cells, open cells, or mixture of closed cells and open cells is aerated and the plurality of closed cells, open cells, or mixture of closed cells and open cells remains aerated throughout the polishing life of the polishing pad.

2. The polishing pad of claim 1, wherein the nonporous microlayer has an average thickness of less than fifty percent of the average diameter of the multilayered microholes within the polymer network.

3. The polishing pad of claim 1, wherein the plurality of layers comprises a mixture of the closed cells and open cells and the closed cells are spherical and the open cells comprise oval cells.

4. The polishing pad of claim 1, wherein the plurality of layers comprises macro-features extending into the subpad for adjusting a polishing profile of the chemical mechanical polishing pad.

5. The polishing pad of claim 1, wherein the polymer matrix comprises closed cell pores, the closed cells are pores, and a bottom surface of the polishing pad comprises open pores, and the nonporous microlayer abuts the open pores to at least partially fill the open pores of the bottom surface of the polishing pad.

6. A chemical mechanical polishing pad comprising:

A porous polymer network, the porous polymer network comprising:

Ii) a plurality of closed cells, open cells, or a mixture of closed cells and open cells adjacent to the single-layer closed cells, wherein the plurality of closed cells, open cells, or mixture of closed cells and open cells is aerated and the plurality of closed cells, open cells, or mixture of closed cells and open cells remains aerated throughout the polishing life of the polishing pad, and the polishing pad has a porosity and the porous subpad has a porosity greater than the porosity of the polishing pad.

7. The polishing pad of claim 6, wherein the nonporous microlayer has an average thickness of less than fifty percent of the average diameter of the multilayered microholes within the polymer network.

8. The polishing pad of claim 6, wherein the plurality of layers comprises a mixture of the closed cells and open cells and the closed cells are spherical and the open cells comprise oval cells.

9. The polishing pad of claim 6, wherein the plurality of layers comprises a series of macro-features extending into the subpad for conditioning a polishing profile of the chemical mechanical polishing pad.

10. The polishing pad of claim 6, wherein the polishing layer has a bottom surface and the bottom surface comprises an annular groove that extends into the polishing layer without penetrating the polishing surface of the polishing layer, and the subpad fills the annular groove.