Chemical mechanical polishing/planarization (CMP) is a process of smoothing surfaces with the combination of chemical and mechanical forces. The process uses an abrasive and corrosive chemical slurry in conjunction with a polishing pad. The CMP process can remove material on a wafer and tends to even out irregular topography of the wafer, making the wafer flat or planar.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
The present disclosure will be described with respect to embodiments in a specific context, a polishing layer of a polishing pad having first and second grooves respectively at different horizontal levels. The first and second grooves may be used to accommodate slurry for polishing a wafer. When the second groove in the top surface of the polishing layer exists, the slurry may flow into the second groove and may be stored by the second groove for polishing the wafer. After the second groove is worn out and disappeared, the first groove buried in the polishing layer is exposed through the top surface of the polishing layer. As a result, the slurry may flow into the first groove and may be stored by the first groove for continuously polishing the wafer. The embodiments of the disclosure may also be applied, however, to a variety of polishing pads. Various embodiments will be explained in detail with reference to the accompanying drawings.
The polishing layer 122 is located on the first support layer 128 and has a top surface 123 and a bottom surface 125. The bottom surface 125 faces away from the top surface 122 and faces the first support layer 128. The polishing layer 122 has at least one first groove 124 and at least one second groove 126. In some embodiments, the second groove 126 may be a cavity buried at least beneath the top surface 123 of the polishing layer 122. The first groove 124 is present on the top surface 123 of the polishing layer 122. In some embodiments, the second groove 126 is a groove having an opening 1262 on the bottom surface 125 of the polishing layer 122, and the opening 1262 of the second groove 126 is covered by the first support layer 128, such that the second groove 126 can be considered a buried groove. On the other hand, the first groove 124 is an open groove in the top surface 123 of the polishing layer 122.
In other words, the top surface 123 of the polishing layer 122 has the first groove 124 therein, and the bottom surface 125 of the polishing layer 122 has the second groove 126 therein. The first and second grooves 124, 126 are respectively present at opposite sides of the polishing layer 122, and the opening direction D3 of the first groove 124 faces away from the opening direction D4 of the second groove 126. It is to be noted that the number of the first and second grooves 124, 126 of the polishing layer 122 shown in
In some embodiments, the first and second grooves 124, 126 of the polishing layer 122 may be in a concentric arrangement, but various embodiments of the present disclosure are not limited in this regard.
As shown in
As shown in
As shown in
Furthermore, due to the polishing layer 122 has the first and second grooves 124, 126 to accommodate the slurry 132, the number of wafers polished by the polishing layer 122 accommodating the slurry 132 is increased. Therefore, the life time of the polishing pad 120 may be extended. Accordingly, when the polishing layer 122 of the polishing pad 120 having the first and second grooves 124, 126 is used in the chemical-mechanical polishing apparatus 100, the number of preventive maintenances (PM) for the polishing pad 120 during a period of time may be decreased, so that the operation time of the chemical-mechanical polishing apparatus 100 may be extended.
Moreover, if the wafer 210 is usually polished on an edge portion of the polishing layer 122, such as the position of the wafer 210 shown in
As shown in
In some embodiments, the top surface 123 of the polishing layer 122 has a plurality of first grooves 124 therein and the bottom surface 125 of the polishing layer 122 has a plurality of second grooves 126 therein. The orthogonal projection of each of the second grooves 126 on the top surface 123 is between two adjacent first grooves 124.
The polishing pad 120 may further include a second support layer 129, and the first support layer 128 is located between the second support layer 129 and the polishing layer 122. In some embodiments, the hardness of the second support layer 129 is greater than the hardness of the first support layer 128, and the hardness of the first support layer 128 is greater than the hardness of the polishing layer 122, but various embodiments of the present disclosure are not limited in this regard. As a result of such a design, the second support layer 129 is used to support the first support layer 128 and the polishing layer 122.
In some embodiments, a perpendicular distance d2 between the bottom portion 1261 of the second groove 126 and the top surface 123 may be smaller than or equal to a perpendicular distance d3 between the bottom portion 1241 of the first groove 124 and the top surface 123. If the perpendicular distance d2 between the bottom portion 1261 and the top surface 123 is smaller than the perpendicular distance d3 between the bottom portion 1241 and the top surface 123, the polishing layer 122 having such first and second grooves 124, 126 may ensure that the second groove 126 is exposed through the top surface 123 before the first groove 124 is worn out. If the perpendicular distance d2 between the bottom portion 1261 and the top surface 123 is equal to the perpendicular distance d3 between the bottom portion 1241 and the top surface 123, such polishing layer 122 may ensure that the first groove 124 is worn out and the second groove 126 is exposed through the top surface 123 simultaneously.
In some embodiments, the polishing layer 122 has at least one first protruding portion 121a and at least one second protruding portion 121b. The first protruding portion 121a may be referred to as a solid portion that separates at least two of the first grooves 124, and the second groove 126 is buried at least beneath the first protruding portion 121a of the polishing layer 121a. The first protruding portion 121a is adjacent to the first groove 124, and the second protruding portion 121b is adjacent to the second groove 126. Moreover, the first groove 124 may be aligned with the second protruding portion 121b, and the second groove 126 may be aligned with the first protruding portion 121a. As a result, the first and second grooves 124, 126 are alternatively arranged in the polishing layer 122. After the first protruding portion 121a is ground by the slurry 132 (see
The polishing pad 120a may further include an adhesive 1282. The adhesive 1282 is present at least between the first support layer 128a and the polishing layer 122, and at least a portion of the adhesive 1282 is present in the recess 1281. During assembling the polishing layer 122 and the first support layer 128a, the adhesive 1282 may be coated on a surface of the first support layer 128a having the recess 1281. Thereafter, the polishing layer 122 may be adhered to the surface of the first support layer 128a. Since the first support layer 128a has the recess 1281 therein, the excess adhesive 1282 may flow into the recess 1281. As a result of such a design, the recess 1281 in the first support layer 128a may prevent the excess adhesive 1282 from flowing into the second groove 126 of the polishing layer 122, such that space in the second groove 126 is not occupied by the adhesive 1282. In other words, the recess 1281 of the first support layer 128a may ensure that the space of the second groove 126 is used to accommodate the slurry.
In some embodiments, the first groove 124a of the polishing layer 122a may be aligned with the first groove 124 of the polishing layer 122, and the second groove 126a of the polishing layer 122a may be aligned with the second groove 126 of the polishing layer 122.
When the polishing pad 120b is used in a chemical-mechanical polishing apparatus, due to the polishing pad 120b has four layers of grooves including the first groove 124a, the second groove 126a, the third groove 124, and the fourth groove 126 respectively at different horizontal levels, such configuration may extend the life time of the polishing pad 120b, and may decrease the number of preventive maintenances (PM) for the polishing pad 120b.
In some embodiments, the polishing layer of the polishing pad may be formed by three-dimensional (3D) printing. For example, the polishing layer may be formed by selective laser sintering (SLS) of 3D printing. In some embodiments, a 3D printer may utilize polyurethane to manufacture the polishing pad that includes the polishing layer. The method of selective laser sintering may form the first and second grooves respectively in the top surface and the bottom surface of the polishing layer. In addition, the precision of the polishing pad may be in a range about 0.2 mm to 1.2 mm and the precision of selective laser sintering may be smaller than about 0.07 mm, so that the method of selective laser sintering may comply with the precision of the polishing pad.
Alternatively, the first groove may be formed by machining the top surface of the polishing layer, and the second groove may be formed by machining the bottom surface of the polishing layer. “Machining” used herein means that any of various processes in which a piece of raw material is cut into a desired final shape and size by a controlled material-removal process.
In some embodiments, the polishing pad may be formed by maturing. The forming the polishing layer may include the following steps. A first layer of the polishing layer is formed. Thereafter, a first mask is disposed on the first layer of the polishing layer. Afterwards, the first layer of the polishing layer is matured after the disposing the first mask. Next, the first mask is moved from the first layer of the polishing layer to create at least one groove space in the first layer of the polishing layer. Subsequently, a second layer of the polishing layer is formed on the first layer of the polishing layer, and the groove space is buried beneath the second layer of the polishing layer to be the first groove. The first and second layers may be made of material including polyurethane, but various embodiments of the present disclosure are not limited in this regard, other materials (e.g., rubber) may be also used to form the polishing pad through maturing.
Moreover, the forming the polishing layer may further include the following steps. A second mask is disposed on the second layer of the polishing layer. Thereafter, the second layer of the polishing layer is matured after the disposing the second mask. Subsequently, the second mask is removed from the second layer of the polishing layer to create the second groove in the second layer of the polishing layer. In the following description, a polishing method will be described.
In some embodiments, the dispensing the slurry further includes dispensing at least another portion of the slurry into the exposed buried groove.
In order to maintain a specific quantity of slurry on a polishing pad and extend the life time of the polishing pad, a polishing pad for a chemical-mechanical polishing apparatus, a method for manufacturing the polishing pad, and a polishing method are designed to accommodate the slurry in the first groove and/or the second groove that are respectively at two opposite sides of the polishing layer. When the slurry is dispensed onto the polishing layer of the polishing pad, the first groove in the top surface of the polishing layer may accommodate the slurry. After the top surface of the polishing layer is ground by a number of wafers for a period of time, the first groove may be worn out and disappeared. However, at this moment, the second groove in the bottom surface of the polishing layer may be exposed through the top surface to continuously accommodate the slurry. As a result, the planarization and the yield rate of the wafer may be improved, and the usage amount of the slurry may be reduced, and the life time of the polishing pad may be extended. Furthermore, the number of preventive maintenances (PM) for the polishing pad during a period of time may be decreased, so that the operation time of the chemical-mechanical polishing apparatus may be extended.
In accordance with some embodiments of the present disclosure, a polishing pad for a chemical-mechanical polishing apparatus includes a first support layer and a polishing layer. The polishing layer is present on the first support layer. The polishing layer has a top surface that faces away from the first support layer and at least one first cavity that is buried at least beneath the top surface of the polishing layer.
In accordance with some embodiments of the present disclosure, a method for manufacturing a polishing pad includes forming a polishing layer having a top surface, at least one first groove and at least one second groove, in which the first groove and the second groove are separated from the top surface of the polishing layer at different vertical distances. The polishing layer is bonded onto at least one support layer, in which the top surface of the polishing layer faces away from the support layer after the bonding.
In accordance with some embodiments of the present disclosure, a polishing method includes dispensing slurry onto a polishing pad, in which the polishing pad has at least one open groove and at least one buried groove, and the dispensing the slurry dispenses at least a portion of the slurry into the open groove. At least one workpiece is held against the polishing pad. The workpiece is rotated relative to the polishing pad, in which the polishing pad is worn to expose the buried groove during the rotating.
Although the present disclosure has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the present disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
This application is a divisional of and claims priority to U.S. Non-Provisional application Ser. No. 15/158,529, titled “POLISHING PAD, METHOD FOR MANUFACTURING POLISHING PAD, AND POLISHING METHOD” and filed on May 18, 2016, which claims priority to U.S. Provisional Application Ser. No. 62/261,016, titled “INVISIBLE LAMINATION CMP PAD GROOVING” and filed on Nov. 30, 2015. U.S. Non-Provisional application Ser. No. 15/158,529 and U.S. Provisional Application Ser. No. 62/261,016 are herein incorporated by reference.
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Number | Date | Country | |
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Parent | 15158529 | May 2016 | US |
Child | 16205318 | US |