This application claims the priority benefit of Taiwan application serial no. 100124629, filed on Jul. 12, 2011. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
1. Field of the Invention
The invention relates to a polishing pad, a polishing method, and a polishing system. More particularly, the invention relates to a polishing pad, a polishing method, and a polishing system enabling a slurry to have a different flow distribution.
2. Description of Related Art
With the progress of the industries, planarization processes are often adopted as processes for manufacturing various devices. Chemical mechanical polishing (CMP) processes are often used in the planarization processes in the industries. General speaking, the chemical mechanical polishing processes are performed by supplying a slurry which has chemical mixtures on a polishing pad, applying a pressure on the article to be polished to press it on the polishing pad, and providing a relative motion between the article and the polishing pad. Through the mechanical friction generated by the relative motion and the chemical effects of the slurry, a portion of the surface layer of the article is removed to make the surface flat and smooth so as to achieve planarization.
Conventional polishing pad includes a polishing layer and a plurality of circular grooves disposed in the polishing layer. The circular grooves are disposed in a concentric arrangement in the polishing layer, for example. During the polishing process, a portion of the slurry flows outward in a radial direction from the circular grooves to the surface of the polishing layer due to the centrifugal force generated from the rotation of the polishing pad. Nevertheless, most of the slurry is still contained in the circular grooves and only a small portion flows to the surface of the polishing layer.
Another conventional polishing pad includes a polishing layer and a plurality of edge extending grooves disposed in the polishing layer. The edge extending grooves, for example, are disposed in a radial or spiral arrangement in the polishing layer and extend to an edge of the polishing layer. In the polishing process, the relative motion between a carrier ring in the polishing system and the edge extending grooves causes most of the slurry to be squeezed over the edge of the polishing layer by the carrier ring and then flows out, while only a small portion of the slurry flows between the surface of the polishing layer and the substrate.
During the polishing process, a flow distribution of the slurry affects polishing characteristics. Therefore, it is necessary to provide polishing pads which have different flow distributions for industry in response to the requirements of various polishing processes.
Accordingly, the present invention provides a polishing pad, a polishing method, and a polishing system enabling a slurry to have a different flow distribution.
The present invention further provides a polishing pad used in conjunction with a carrier ring to polish a substrate. The polishing pad has a motion direction when polishing, where the carrier ring has at least one carrier groove and the substrate has a substrate radius. The polishing pad includes a polishing layer and a surface pattern disposed in the polishing layer. The surface pattern having a plurality of traversing grooves. An angle between a tangent line of each of the traversing grooves and a tangent line of the motion direction is non-zero. Each of the traversing grooves respectively has a traversing groove trajectory corresponding to the motion direction. Each of the traversing groove trajectories has a trajectory width smaller than the substrate radius. Additionally, in a leading region of the carrier ring corresponding to the motion direction, the traversing grooves have at least one carrier compatible groove. Here, the at least one carrier compatible groove aligns with the at least one carrier groove.
The present invention further provides a polishing pad used in conjunction with a carrier ring to polish a substrate. The polishing pad has a motion direction when polishing, where the carrier ring has at least one carrier groove and the substrate has a substrate radius. The motion direction is perpendicular to a coordinate axis extended from an origin point. The polishing pad includes a polishing layer and a surface pattern disposed in the polishing layer. The surface pattern has a plurality of traversing grooves. The traversing grooves each has two terminals located at a first position and a second position of the coordinate axis respectively. A first distance is from the first position to the origin point. A second distance is from the second position to the origin point. The second distance is larger than the first distance, and a difference between the second distance and the first distance is smaller than the substrate radius. Additionally, in a leading region of the carrier ring corresponding to the motion direction, the traversing grooves have at least one carrier compatible groove. Here, the at least one carrier compatible groove aligns with the at least one carrier groove.
The present invention further provides a polishing method. In the polishing method, a polishing pad is provided. The polishing pad includes a polishing layer and a surface pattern disposed in the polishing layer. The surface pattern has a plurality of traversing grooves. A carrier is then provided. The carrier has a carrier ring for holding a substrate within the carrier, where the carrier ring has at least one carrier groove and the substrate has a substrate radius. Thereafter, the substrate is pressed on the polishing pad with the carrier to perform a polishing process. The polishing pad has a motion direction during the polishing process. An angle between a tangent line of each of the traversing grooves of the polishing pad and a tangent line of the motion direction is non-zero. Each of the traversing grooves respectively has a traversing groove trajectory corresponding to the motion direction. Each of the traversing groove trajectories has a trajectory width smaller than the substrate radius. Additionally, in a leading region of the carrier ring corresponding to the motion direction, the traversing grooves have at least one carrier compatible groove. Here, the at least one carrier compatible groove aligns with the at least one carrier groove.
The present invention further provides a polishing method. In the polishing method, a polishing pad is provided. The polishing pad includes a polishing layer and a surface pattern disposed in the polishing layer. The surface pattern has a plurality of traversing grooves. A carrier is then provided. The carrier has a carrier ring for holding a substrate within the carrier, where the carrier ring has at least one carrier groove and the substrate has a substrate radius. The substrate is pressed on the polishing pad with the carrier to perform a polishing process. The polishing pad has a motion direction during the polishing process, and the motion direction is perpendicular to a coordinate axis extended from an origin point. The traversing grooves each has two terminals located at a first position and a second position of the coordinate axis respectively. A first distance is from the first position to the origin point. A second distance is from the second position to the origin point. The second distance is larger than the first distance, and a difference between the second distance and the first distance is smaller than the substrate radius. Additionally, in a leading region of the carrier ring corresponding to the motion direction, the traversing grooves have at least one carrier compatible groove. Here, the at least one carrier compatible groove aligns with the at least one carrier groove.
The present invention further provides a polishing system including a polishing pad, a carrier, and a substrate. The polishing pad includes a polishing layer and a surface pattern disposed in the polishing layer. The surface pattern has a plurality of traversing grooves. The carrier has a carrier ring including at least one carrier groove. The substrate is held within the carrier and has a substrate radius. The polishing pad has a motion direction when the carrier presses the substrate on the polishing pad for polishing. An angle between a tangent line of each of the traversing grooves of the polishing pad and a tangent line of the motion direction is non-zero. Each of the traversing grooves respectively has a traversing groove trajectory corresponding to the motion direction. Each of the traversing groove trajectories has a trajectory width smaller than the substrate radius. Additionally, in a leading region of the carrier ring corresponding to the motion direction, the traversing grooves have at least one carrier compatible groove. Here, the at least one carrier compatible groove aligns with the at least one carrier groove.
The present invention further provides a polishing system including a polishing pad, a carrier, and a substrate. The polishing pad includes a polishing layer and a surface pattern disposed in the polishing layer. The surface pattern has a plurality of traversing grooves. The carrier has a carrier ring including at least one carrier groove. The substrate is held within the carrier and has a substrate radius. The polishing pad has a motion direction when the carrier presses the substrate on the polishing pad for polishing. The motion direction is perpendicular to a coordinate axis extended from an origin point. The traversing grooves each has two terminals located at a first position and a second position of the coordinate axis respectively. A first distance is from the first position to the origin point. A second distance is from the second position to the origin point. The second distance is larger than the first distance, and a difference between the second distance and the first distance is smaller than the substrate radius. Additionally, in a leading region of the carrier ring corresponding to the motion direction, the traversing grooves have at least one carrier compatible groove. Here, the at least one carrier compatible groove aligns with the at least one carrier groove.
In light of the foregoing, the traversing grooves of the polishing pad in the invention have at least one carrier compatible groove in the leading region of the carrier ring corresponding to the motion direction, and the at least one carrier compatible groove aligns with the at least one carrier groove. Thus, during the polishing process, the slurry generates the corresponding flow distribution along the grooves so as to provide better polishing efficiency.
In order to make the aforementioned and other features and advantages of the invention more comprehensible, several embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the invention.
The polishing layer 102 may be made of polymer materials such as polyester, polyether, polyurethane, polycarbonate, polyacrylate, polybutadiene, or other polymer materials synthesized by suitable thermosetting resin or thermoplastic resin. In addition to the polymer materials, the polishing layer 102 may further include conductive materials, abrasive particles, microspheres, or soluble additives in the polymer materials.
The surface pattern 104 is disposed in the polishing layer 102. According to the present embodiment, the surface pattern 104 includes a plurality of traversing grooves 104a-104d. In the embodiment shown in
In addition, according to the present embodiment, the surface pattern 104 may further include at least one partition blank region B1-B3, the partition blank regions B1-B3 separate the traversing grooves 104a-104d, so that the traversing grooves 104a-104d do not connect to one another. Herein, the partition blank regions B1-B3 have a ring-shaped distribution on the polishing pad 100, and the traversing grooves 104a-104d collectively have an annulus distribution on the polishing pad 100.
In the present embodiment, the surface pattern 104 further includes an edge blank region E disposed on an edge of the polishing layer 102. The edge blank region E prevents the traversing grooves 104a-104d from extending to the edge of the polishing layer 102. The surface pattern 104 may optionally include a central blank region disposed close to a center of the polishing layer 102 (as shown in
Furthermore, the carrier 110 includes a carrier ring 111 disposed at periphery of the carrier 110. The carrier ring 111 is mainly adopted to hold a substrate S within the carrier 110, such that the substrate S is pressed on a surface of the polishing layer 102 for polishing. Generally, the carrier ring 111 of the carrier 110 includes at least one carrier groove 112. The carrier ring 111 is a ring structure located at periphery of the carrier 110. The substrate S is held within the carrier 110 and encircled in the carrier ring 111.
Moreover, the substrate S is also referred as a polishing object, which includes a wafer, a glass substrate, a metal substrate, or other polishing objects, for example. The substrate S is pressed on the polishing layer 102 by the carrier 110 for polishing. The substrate S has a substrate radius r.
To perform a polishing process, the carrier 110 can hold and press the substrate S on the polishing layer 102 to perform the polishing process. When performing the polishing process, the polishing pad 100 has a motion direction D1. The motion direction D1 is perpendicular to a coordinate axis (for example, a radius coordinate axis) extended from an origin point (for example, a rotational center C) of the polishing pad 100. In other words, the polishing pad 100 rotates along the direction D1. Also, the carrier 110 holds the substrate S and rotates along a direction D2. With the polishing pad 100 rotating along the direction D1 and the carrier 110 rotating along the direction D2, a surface of the substrate S can be polished.
It should be noted that when performing the polishing process, an angle between a tangent line of each of the traversing grooves 104a-104d and a tangent line of the motion direction D1 of the polishing pad 100 is not equal to 0. That is, the tangent line of each of the traversing grooves 104a-104d and the tangent line of the motion direction D1 of the polishing pad 100 are not disposed in parallel. Therefore, the traversing grooves 104a-104d are generally arranged in a direction extending from the position closer to the rotational center C of the polishing pad 100 to the position closer to an edge of the polishing pad 100.
Further, the traversing grooves 104-104d respectively have a plurality of groove trajectories A1-A4 corresponding to the motion direction D1 of the polishing pad 100. In other words, when the polishing pad 100 rotates along the motion direction D1, the traversing groove 104a constitutes a groove trajectory A1 (that is, an outermost ring region), the traversing groove 104b constitutes a groove trajectory A2 (that is, a second outermost ring region), the traversing groove 104c constitutes a groove trajectory A3 (that is, a third outermost ring region), and the traversing groove 104d constitutes a groove trajectory A4 (that is, an innermost ring region). A width of each of the groove trajectories A1-A4 is, for example, larger than a width of each of the partition blank regions B1-B3 and a width of the edge blank region E. Here, the trajectory width of the groove trajectories A1-A4 means that when two terminals of the traversing groove extend outward from a first radius position to a second radius position relative to the rotational center C, a difference between the second radius and the first radius then equals to the trajectory width.
In the present embodiment, the width of each of the groove trajectories A1-A4 is smaller than the substrate radius r of the substrate S. That is, the traversing grooves 104a-104d each has two terminals located at a first position and a second position of the coordinate axis respectively. A first distance is from the first position to the origin point. A second distance is from the second position to the origin point. A difference between the second distance and the first distance is smaller than the substrate radius r. Take the traversing groove 104a as an example, a first terminal T1 of the traversing groove 104a is located at an outermost position of the partition blank region B1 and a second terminal T2 of the traversing groove 104a is located at an innermost position of the edge blank region E. A first distance is from the first terminal T1 of the traversing groove 104a to the origin point (the rotational center C). A second distance is from the second terminal T2 of the traversing groove 104a to the origin point (the rotational center C). A difference between the second distance and the first distance is smaller than the substrate radius r of the substrate S.
Accordingly, in the present embodiment, at least two of the non-completely overlapped groove trajectories among the groove trajectories A1-A4 and at least one partition blank region among the partition blank regions B1-B3 are covered by the substrate S.
It should be noted that the invention does not limit the number of the groove trajectories A1-A4 and the partition blank regions B1-B3. In other embodiments, the number of the groove trajectories in the polishing layer 102 can be more than or less than four, and the number of the partition blank regions can be more than or less than three. The number of the groove trajectories and the partition blank region can be altered suitably depending on demands as long as the guidelines of the invention are followed.
Further, according to the present embodiment, the traversing grooves 104a-104d are generally arranged as continuous curves virtually extended in radial direction on the polishing layer 102. The continuous curves virtually extended in radial direction have a spiral distribution or a radiant distribution collectively. In other words, the traversing grooves 104a-104d extend virtually from the position closer to the rotational center C of the polishing layer 102 to the position closer to an edge of the polishing layer 102 radially in a spiral or a radiant arrangement.
Moreover, the invention does not limit the number of the traversing grooves 104a-104d. In order to better illustrate the invention, only several of the traversing grooves 104a-104d are shown in the embodiment of
In general, when performing the polishing process, the polishing pad 100 rotates along the direction D1 and the carrier 110 rotates along the direction D2, so that the polishing pad 100 and the carrier 110 have a relative motion. However, in the polishing process aforementioned, a portion of the slurry flows to the edge of the polishing layer 102 due to the centrifugal force generated from the rotation of the polishing pad 100. Especially, at the contact region of the polishing layer 102 and the carrier 110, the slurry is further squeezed by the carrier ring 111 of the carrier 110 to the edge of the polishing layer 102 and thus flows out. It is more obvious in the leading region of the carrier ring 111 of the carrier 110 corresponding to the motion direction D1. According to the present embodiment, the leading region of the motion direction D1 generally corresponds to a lower edge region of the carrier ring 111 of the carrier 110.
Therefore, according to the present embodiment, the traversing grooves 104a-104d of the surface pattern 104 in the polishing layer 102 have at least one carrier compatible groove 140 in the leading region of the carrier ring 111 corresponding to the motion direction D1. The carrier compatible groove 140 aligns with the carrier groove 112 of the carrier ring 111. In details, among the traversing grooves 104a-104d in the polishing layer 102, at least one of the traversing grooves 104a-104d aligns with the carrier groove 112 of the carrier ring 111, and this traversing groove is referred as the carrier compatible groove 140. In the present embodiment, the carrier compatible groove 140 is disposed in the leading region of the carrier ring 111 corresponding to the motion direction D1.
Accordingly, the carrier compatible groove 140 of the present embodiment aligns with the carrier groove 112 in the leading region of the carrier ring 111 corresponding to the motion direction D1 so as to prevent the slurry from flowing out of the edge of the polishing layer 102 due to the squeezing of the carrier ring 111. In other words, a portion of the slurry is drawn into the carrier ring 111 by the rotation of the carrier 110 (the rotational direction D2) during the polishing with the facilitation of the design of the traversing grooves 104a-104d in the polishing layer 102 (the alignment of the carrier compatible groove 140 and the carrier groove 112). In addition, the width of each of the groove trajectories A1-A4 of the traversing grooves 104a-104d is smaller than the substrate radius r of the substrate S, that is, at least two non-completely overlapped groove trajectories and at least one partition blank region are covered by the substrate S. Consequently, the slurry not only flows from two sidewalls of the traversing grooves 104a-104d to an interface between the surface of the polishing layer 102 and the substrate S, but also flows from the terminals of the traversing grooves 104a-104d to the interface between the surface of the polishing layer 102 and the substrate S, thus it enables the slurry to have a different flow distribution.
In the embodiments shown in
In the embodiments illustrated in
In the embodiments shown in
Similarly, the carrier compatible groove 240 of the present embodiment aligns with the carrier groove 112 in the leading region of the carrier ring 111 corresponding to the motion direction D1. The slurry is thus prevented from flowing out of the edge of the polishing layer 102 due to the squeezing of the carrier ring 111. Therefore, a portion of the slurry is drawn into the carrier ring 111 by the rotation of the carrier 110 (the rotational direction D2) during the polishing. In addition, the width of each of the groove trajectories of the traversing grooves 104 is smaller than the substrate radius r of the substrate S, that is, at least two non-completely overlapped groove trajectories and at least one partition blank region are covered by the substrate S. Consequently, the slurry not only flows from two sidewalls of the traversing grooves 104 to an interface between the surface of the polishing layer 102 and the substrate S, but also flows from the terminals of the traversing grooves 104 to the interface between the surface of the polishing layer 102 and the substrate S, thus it enables the slurry to have a different flow distribution.
In the embodiment shown in
In addition, in the present embodiment of
In the embodiments depicted in
In summary, the traversing grooves of the polishing pad in the invention have at least one carrier compatible groove in the leading region of the carrier ring corresponding to the motion direction, and the at least one carrier compatible groove aligns with the at least one carrier groove. Accordingly, when performing the polishing process, the slurry flows along the grooves to generate the corresponding flow distribution.
The polishing pad of the invention allows the slurry to obtain a different flow distribution. For certain polishing processes, the slurry may be used more efficiently so as to reduce the consumption of the slurry, thereby decreasing the cost. For other certain polishing processes, different polishing performances such as enhancing the polishing rate of the substrate or reducing the polishing time may be obtained as options for the industry.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosed embodiments without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
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