JP5917236B2 - Polishing pad sheet and manufacturing method thereof, polishing pad and manufacturing method thereof, and polishing method - Google Patents

Description

  The present invention relates to a polishing pad sheet and a manufacturing method thereof, a polishing pad and a manufacturing method thereof, and a polishing method.

  Conventionally, polishing using a polishing pad is known as means for flattening the surfaces of various semiconductor devices such as magnetic disks and glass substrates for liquid crystal displays. In general, a chemical mechanical polishing (hereinafter referred to as “CMP”) method is employed in polishing in the manufacturing process of a semiconductor device or the like. In the CMP method, a slurry (polishing liquid) in which abrasive grains (polishing particles) are dispersed in an alkali or acid solution is usually used. By polishing while supplying the slurry to the polishing surface of the object to be polished, the object to be polished is flattened by the mechanical polishing action by the abrasive grains contained in the slurry and the chemical polishing action by the alkali or acid solution. The In recent years, high flatness and precision have been demanded for polishing by the CMP method, particularly for the purpose of improving the quality of objects to be polished such as semiconductor devices.

  For example, in Patent Document 1, the object to be polished is precisely intended in order to provide a polishing cloth for precision polishing and a method for manufacturing the same, which can sufficiently draw out the ability of the polishing liquid and perform good precision polishing. Polishing for precision polishing, characterized in that a polishing cloth for precision polishing for polishing, wherein, among the open holes existing on the surface, 90% or more of the holes having a diameter of 0.1 to 10 μm are provided. A cloth has been proposed.

JP 2005-335028 A

  However, in the conventional polishing process including the one described in Patent Document 1, even if it is possible to obtain an object to be polished having excellent surface quality, the productivity of the object to be polished is reduced as the polishing rate decreases. Will also be low. On the other hand, if high productivity is to be ensured, the surface quality of the object to be polished will deteriorate.

  Accordingly, the present invention has been made in view of the above circumstances, and a polishing pad capable of maintaining high productivity of an object to be polished and having excellent surface quality of the object to be polished, and a method for manufacturing the same An object of the present invention is to provide a polishing pad sheet, a manufacturing method thereof, and a polishing method.

  As a result of intensive studies to achieve the above object, the present inventors have found that the polishing pad can have both excellent surface quality of the object to be polished and a high polishing rate by having bubbles in a specific mode. The headline and the present invention were completed.

That is, the present invention is a polishing pad sheet comprising a resin sheet in which a plurality of bubbles having elongated portions are formed, and among the plurality of bubbles appearing in a cross section parallel to the thickness direction of the resin sheet, the number of bubbles the length direction of the elongated portion at 50% or more bubbles in the standards, are formed to be inclined at an angle of 10 to 65 ° in a predetermined direction with respect to the in-plane direction of the resin sheet, the upper Symbol resin sheet An embossed groove is formed on the main surface of the resin sheet, and the length direction of the elongated portion is inclined on the main surface of the resin sheet by 10 to 65 ° in a fixed direction with respect to the in-plane direction of the resin sheet. It is a sheet | seat which has the opening of the bubble of at least one part of the said bubble formed in . Note that the “long direction of the elongated portion” of the bubble is the direction of the longest line segment connecting any two points of the bubble wall surface and the opening end when there is an opening in the cross section. Say. However, if the wall on the inclined side of the bubble has a portion inclined less than 90 ° with respect to the in-plane direction and a portion inclined more than 90 °, a straight line (usually the above surface) A region including a portion inclined by less than 90 ° in a region divided by a straight line parallel to the inward direction is referred to as an “elongate portion”, and a line having the intersection of the straight line with the bubble wall surface at both ends in the elongated portion. A line segment connecting a midpoint (for example, a point e in FIG. 3) of a minute (for example, a point e in FIG. 3), a bubble wall surface, and an arbitrary point of the opening end if there is an opening. The direction of the longest line segment (for example, dotted line f in FIG. 3).

  According to the present invention, the length direction of the elongated portion is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet in the bubbles of 50% or more on the basis of the number of bubbles among the plurality of bubbles having the elongated portion. Therefore, the bubble openings appearing on the main surface of the resin sheet are arranged so as to be shifted from each other in the thickness direction of the resin sheet with respect to the end opposite to the bubble openings. As a result, when the object to be polished moves on the polishing pad toward the polishing surface of the polishing pad and moves in the in-plane direction of the polishing surface, the end of the bubble passes through the vicinity of the tip in the moving direction of the object to be polished. When the periphery of the part is pressed, the opening of the bubble having the end becomes difficult to be blocked by the object to be polished. Thereby, the slurry (polishing liquid) held in the bubbles can be efficiently discharged from the opening. Moreover, at least a part of the opening that appeared on the polished surface of the resin sheet before forming the embossed groove is blocked by melting and plastic deformation of the resin accompanying the formation of the embossed groove. As a result, the function of the groove formed in the polishing pad for efficiently and surely spreading the slurry over the entire surface of the polishing pad and discharging it to the outside of the system is maintained, and the slurry on the polishing surface with which the object to be polished comes into contact is maintained. The holding can be reliably performed.

  Furthermore, the bubble having an elongated portion whose length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet is compared with the case where the bubble does not have such an elongated portion. The wall portion due to the matrix resin existing in is inclined with respect to the thickness direction of the resin sheet. When a groove is formed by cutting the resin sheet in such a state, a part of the inclined wall portion is cut, so when pressed in the thickness direction of the resin sheet during polishing, The part easily collapses, it becomes difficult to hold the slurry, which is the original function of the bubbles, and the part of the collapsed wall becomes a foreign object during polishing and damages the object to be polished. On the other hand, according to the present invention, when the embossed groove is formed, the resin is melted and plastically deformed. Therefore, the groove is formed without cutting the wall portion existing between the bubbles as compared with the case of cutting. Can do. Therefore, despite the fact that the wall portion between the bubbles is inclined with respect to the thickness direction of the resin sheet, it becomes possible to maintain a high slurry holding capacity by the bubbles, and it is possible to suppress the generation of foreign matter, It becomes possible to prevent the object to be polished from being damaged. And the bubble having a long and slender portion whose length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet is compared with the case where the bubbles are not inclined with respect to the thickness direction of the resin sheet. The projected area as viewed from the thickness direction of the resin sheet is increased. Therefore, when the groove is formed by cutting, the size of the opening that appears on the wall surface of the groove becomes larger than when the bubbles are not inclined with respect to the thickness direction of the resin sheet, and it becomes difficult to hold the slurry. However, according to the present invention, since the formation of the embossed groove can suppress the appearance of an opening on the wall surface of the groove, the wall portion between the bubbles is inclined with respect to the thickness direction of the resin sheet. In addition, it is possible to maintain a high slurry holding capacity with bubbles.

  By these, this invention can make the surface quality of a to-be-polished object excellent while maintaining productivity of a to-be-polished object highly.

  In the polishing pad sheet of the present invention, it is preferable that the elongated portion extends from the inside of the resin sheet in the thickness direction toward the main surface. The ratio of the number of openings appearing on the main surface to the area of the main surface is preferably higher than the ratio of the number of openings appearing on the wall surface of the embossed groove to the area of the wall surface of the embossed groove, The ratio of the total area of the openings appearing on the main surface to the area is preferably higher than the ratio of the total area of the openings appearing on the wall surface of the embossed grooves to the area of the wall surface of the embossed grooves. Furthermore, it is preferable that the opening end of the embossed groove has an arc shape in a cross section orthogonal to the length direction of the embossed groove. Among the plurality of bubbles, 50% or more of the bubbles based on the number of bubbles are in a right triangle having a hypotenuse as a line segment connecting the center M1 of the bubble bottom and the center M2 of the opening appearing on the main surface. When the elevation angle when viewing the center M2 from the center M1 is θ, it is preferable that the elevation angle θ is in the range of 30 to 60 °, and the bubble bottom center M1 and In a right triangle whose hypotenuse is the line connecting the vertex M3 on the main surface side, when the elevation angle when viewing the vertex M3 from the center M1 is θ, the elevation angle θ is in the range of 30 to 60 °. It is preferable to be formed as follows. Moreover, it is preferable that the said resin sheet contains 70 mass% or more of polyurethane resins, the compression rate is preferable in it being 7-50%, and it is preferable in it that the 100% modulus of resin contained there is 2-50 MPa.

  The method for producing a polishing pad sheet according to the present invention is such that, among the plurality of bubbles appearing in a cross section parallel to the thickness direction of the resin sheet, the length direction of the elongated portion in the bubbles of 50% or more on the basis of the number of bubbles is the above resin sheet. A first step of forming a plurality of bubbles in the precursor sheet of the resin sheet so as to be inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction, and an emboss groove on the main surface of the precursor sheet And a second step of forming. In the first step, it is preferable to form the precursor sheet by removing the solvent after solidifying and regenerating the resin in the coating film of the resin solution containing the resin and the solvent, and the first step In the above, when the resin in the coating film is solidified and regenerated into a sheet, it is preferable that the bubbles are formed with the in-plane direction of the coating film inclined from the horizontal. Moreover, it is preferable that the said resin contains 70 mass% or more of polyurethane resins, and it is preferable to further have the process of grinding the said precursor sheet | seat before a 2nd process.

  The polishing pad of the present invention is obtained from the above-mentioned polishing pad sheet, and its production method includes a step of forming the above-mentioned polishing pad sheet. The polishing method of the present invention includes a step of polishing an object to be polished using the polishing pad, and in that step, the object to be polished is preferably polished by a CMP method.

  According to the present invention, while maintaining the productivity of the object to be polished high, the polishing pad capable of improving the surface quality of the object to be polished and the manufacturing method thereof, the sheet for the polishing pad and the manufacturing method thereof, In addition, a polishing method can be provided.

It is a schematic sectional drawing which shows an example of the sheet | seat for polishing pads of this invention. It is the schematic sectional drawing to which a part of FIG. 1 was expanded. (A) is the schematic which shows the cross-sectional shape of a bubble, (B) is explanatory drawing which shows typically the shape and arrangement | positioning of a bubble. It is explanatory drawing which shows typically the grade of the inclination in a bubble. It is process drawing which shows an example of the manufacturing method of the sheet | seat for polishing pads of this invention. It is a schematic sectional drawing which shows the mode of an example of the grinding | polishing method of this invention.

  Hereinafter, a form for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a schematic cross-sectional view showing an example of the polishing pad sheet of the present embodiment, and FIG. 2 is an enlarged schematic cross-sectional view of a part of the polishing pad sheet shown in FIG. These sectional views are cross sections that appear when the polishing pad sheet is cut in parallel to the thickness direction. The polishing pad sheet 100 is for producing a polishing pad for polishing an object to be polished from the sheet 100, and includes a base 110 and a resin sheet 120 laminated on the base 110. In the resin sheet 120, a plurality of bubbles 122 (those represented by reference numerals 122b, 122c and 122d in the figure are included in the bubbles 122) having an elongated portion 122a are formed. Further, among the plurality of bubbles 122 appearing in a cross section parallel to the thickness direction of the resin sheet 120, the length direction of the elongated portion 122 a in the bubble 122 of 50% or more is in a constant direction with respect to the in-plane direction of the resin sheet 120. It is formed so as to be inclined by 10 to 65 °. And the embossing groove | channel 125 is formed in the main surface 120a of the resin sheet 120. FIG.

  The substrate 110 is in the form of a film and suppresses the polishing pad from expanding, contracting, or bending when polishing using the polishing pad prepared from the polishing pad sheet 100. The material may be used as a base material of a conventional polishing pad, and is not particularly limited. As a material, a flexible material is usually adopted, and examples thereof include polyethylene terephthalate (PET) and other polyesters. The thickness of the substrate may also be a thickness that is employed for a substrate of a conventional polishing pad, and is not particularly limited. The thickness is, for example, 0.1 to 5.0 mm.

  The resin sheet 120 has an integral part of the foamed resin region 120c and the skin layer region 120b in the thickness direction from the substrate 110 side toward the main surface 120a. The composition of the resin sheet 120 is not particularly limited as long as it is the composition containing the most resin (hereinafter referred to as “matrix resin”) serving as a matrix. For example, the resin sheet 120 is a matrix resin relative to the total amount thereof. 70-100 mass% may be included. The resin sheet 120 contains 70-100 mass% of matrix resin more preferably with respect to the whole quantity, More preferably, it contains 75-90 mass%, Most preferably, it contains 80-90 mass%.

  Examples of the matrix resin include polyurethane resin, polysulfone resin, and polyimide resin. These may be used alone or in combination of two or more, and may be used for a resin sheet portion of a conventional polishing pad. Among these, from the viewpoint of more effectively and reliably achieving the object of the present invention, a polyurethane resin is preferable, and the matrix resin preferably includes 50% by mass or more of polyurethane resin, more preferably includes 80% by mass or more. More preferably, it is contained at least 95% by mass, and particularly preferably at least 95% by mass.

  Examples of the polyurethane resin include a polyester-based polyurethane resin, a polyether-based polyurethane resin, and a polycarbonate-based polyurethane resin, and these are used singly or in combination of two or more. Among these, polyester polyurethane resins are preferred from the viewpoint of more effectively and reliably achieving the object of the present invention.

  The polyurethane resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Crisbon (trade name, manufactured by DIC Corporation), Samprene (trade name, manufactured by Sanyo Chemical Industries, Ltd.) and Rezamin (trade name, manufactured by Dainichi Seika Kogyo Co., Ltd.).

  The polysulfone resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Udel (trade name manufactured by Solvay Advanced Polymers Co., Ltd.).

  The polyimide resin may be synthesized by a conventional method, or a commercially available product may be obtained. Examples of commercially available products include Aurum (trade name, manufactured by Mitsui Chemicals, Inc.).

  In addition to the matrix resin, the resin sheet 120 may include a material usually used for a resin sheet of a polishing pad sheet, for example, a pigment such as carbon black, a hydrophilic additive, and a hydrophobic additive. Good. These optionally used materials may be used to control the size, number and inclination of the bubbles 122. Furthermore, various materials such as a solvent used in the manufacturing process of the resin sheet 120 may remain in the resin sheet 120 as long as the solution of the problem of the present invention is not hindered.

  The skin layer region 120b is formed so as to have a main surface 120a that serves as a polishing surface of the polishing pad, and has a thickness of several μm. The skin layer region 120b has a microporous structure in which many fine bubbles are formed in the matrix resin. The fine bubbles have a smaller volume than bubbles formed in the foaming region 120c described in detail later.

  The foamed resin region 120c is formed on the side opposite to the main surface 120a of the skin layer region 120b, and the thickness thereof is not particularly limited, but is, for example, 0.3 to 2.0 mm. In the foamed resin region 120c, a plurality of bubbles 122 having elongated portions 122a are formed in the matrix resin. As the bubbles formed in the foamed resin region 120 c, in addition to the bubbles 122, there are bubbles that do not have an elongated portion, and bubbles that are not inclined in the predetermined direction with respect to the thickness direction of the resin sheet 120. Also good. At least a part of the bubbles 122 has an opening EO that communicates with the main surface 120a via the skin layer region 120b.

  The bubble 122 has an elongated portion 122a, and the length direction of the elongated portion 122a in the bubble of 50% or more, preferably 55% or more of the resin sheet 120 on the basis of the number of bubbles is the surface of the resin sheet 120. It is formed so as to be inclined by 10 to 65 ° in a fixed direction with respect to the inward direction. The elongated portion 122a is preferably extended from the inside of the resin sheet 120 in the thickness direction toward the main surface 120a. The formation of such bubbles 122 can be confirmed by observing a cross section that appears when the resin sheet 120 is cut in the thickness direction so that the inclination is confirmed by a scanning electron microscope. Further, such a ratio of bubbles (based on the number of bubbles) can be measured by performing image processing on a photograph (image) of a cross section observed with a scanning electron microscope as described above. As the arrangement of the three-dimensional shape of the bubbles 122 and the thickness direction of the resin sheet 120, for example, a shape in which an elongated portion at the top of a rounded cone (the bottom surface is on the substrate 110 side) is inclined with respect to the in-plane direction, The shape of the whole rounded cone (the bottom surface is on the substrate 110 side) is inclined with respect to the in-plane direction, and the whole or part of the spindle length is inclined with respect to the in-plane direction. The shape (in this case, the inclined portion corresponds to the elongated portion) may be mentioned. The shape in which the elongated portion at the top of the rounded cone (the bottom surface is on the substrate 110 side) is inclined with respect to the in-plane direction has a cross-sectional shape such as a bubble 122b shown in FIG. There is a shape in which the entire rounded cone (the bottom surface is on the substrate 110 side) is inclined with respect to the in-plane direction, and the cross-sectional shape thereof is, for example, a shape like a bubble 122c shown in FIG. The shape in which the entire length of the spindle shape is inclined with respect to the in-plane direction has a cross-sectional shape such as a bubble 122d shown in FIG.

  Since the bubble 122 is formed so that the elongated portion 122a is inclined in a certain direction with respect to the in-plane direction of the resin sheet 120, when the bubble 122 has the opening EO that appears on the main surface 120a, the center of the opening EO, The center of the end portion EC of the bubble 122 opposite to the opening EO is shifted from each other in the thickness direction. Thus, when the object to be polished moves on the polishing pad made from the polishing pad sheet 100 toward the main surface 120a of the polishing pad and moves in the in-plane direction of the main surface 120a, the object to be polished moves. When the periphery of the end portion EC of the bubble 122 is pressed via the vicinity of the tip in the direction, the opening EO of the bubble 122 having the end portion EC is hardly blocked by the object to be polished. Furthermore, in contrast to the case where the bubbles are not inclined in the longitudinal direction of the elongated portion during polishing, in the present embodiment, the bubbles 122 are pressed in the direction inclined with respect to the elongated portion 122a. Therefore, the bubble 122 is easily deformed by the pressing, and the volume change of the bubble 122 is increased. As a result, the slurry held in the bubbles 122 can be efficiently discharged from the opening EO. In addition, since the length direction of the elongated portion 122a is inclined by 10 ° or more in a certain direction with respect to the in-plane direction of the resin sheet 120, it becomes possible to form large bubbles, so that the slurry can be retained and The discharge can be performed more efficiently.

  The average diameter of the openings EO is not particularly limited, but is preferably, for example, 5 to 20 μm from the viewpoint of precision polishing. If the average diameter of the openings EO is within the above range, scratches due to clogging are less likely to occur, and polishing with higher flatness can be performed. The average diameter (arithmetic average) of the openings EO can be obtained by image analysis of an electron micrograph obtained by photographing an arbitrary surface of the resin sheet 120.

  On the other hand, like the conventional polishing pad, the elongated portions of the bubbles are formed so as to be parallel or substantially parallel to the thickness direction of the resin sheet (perpendicular or substantially orthogonal to the in-plane direction of the resin sheet). When the end of the bubble is pressed through the vicinity of the side end of the object to be polished in the same manner as described above, the opening of the bubble having the end is blocked by the object to be polished. Therefore, it becomes difficult to efficiently discharge the slurry held in the bubbles from the opening.

  Here, a suitable aspect is demonstrated in detail about the case where the bubble 122 is the bubble 122b. 2 is an enlarged view of the elongated portion 122a. With respect to the bubble 122b (the overall cross-sectional shape of the bubble 122b is shown in FIG. 3A), the main surface 120a (the position of the arrow a in FIG. 3A). ), And a position near the center in the thickness direction of the resin sheet 120 (position indicated by an arrow b in FIG. 3A) and a position near the back surface 120d (for example, about 50 to 100 μm inside from the back surface 120d) ((A 3B is a schematic perspective view of the cross section at the position of the arrow c in FIG. On the main surface 120a, an opening EO of the bubble 122b at the center Ma is formed. In the cross section near the center in the thickness direction of the resin sheet 120, a hole HB of the center Mb is formed by the same bubble 122b, and in the cross section near the back surface 120d, a hole HC of the center Mc is formed by the same bubble 122b. The center Ma of the opening EO, the center Mb of the hole HB, and the center Mc of the hole HC are not aligned with each other in the thickness direction and are shifted from each other. That is, the vertical line L passing through the center Ma of the opening EO intersects the cross section at the arrow c at the intersection point Q, and the intersection point Q is located outside the hole HC. Further, when the radius of the hole HC is Rc and the distance between the center Mc of the hole HC and the intersection Q is Lc, the distance Lc is 2 to 5 times the radius Rc. This is preferable because the discharge of the slurry becomes more efficient.

  Here, the degree of inclination of the bubbles 122 formed in the resin sheet 120 will be described with reference to FIG. 4 taking the bubbles 122b as an example. As shown in FIG. 4A, the center M1 is formed by the bubbles 122b on the bottom surface of the resin sheet 120. A straight line passing through the center M1 and perpendicular to the thickness direction (vertical direction in FIG. 4) (horizontal direction in FIG. 4) and the center M2 of the opening EO of the main surface 120a of the bubble 122b (or (B) in FIG. 4). When the bubble 122b is a closed pore, the intersection of the resin sheet 120 passing through the vertex M3) and the straight line in the thickness direction is P, and the line segment connecting the center M1 and the center M2 or the vertex M3 is the hypotenuse. A right triangle is formed. In this right triangle, an elevation angle θ is formed when the center M1 or the vertex M3 is viewed from the center M1. It is preferable that the bubbles 122b are formed so that the elevation angle θ is in the range of 30 to 60 ° as the degree of inclination. That is, it is preferable that the elevation angle θ of the bubbles of 50% or more, preferably 55% or more, based on the number of bubbles is 30 to 60 °. The average value of the elevation angle θ is preferably 70 ° or less, more preferably 65 ° or less, and further preferably 60 ° or less. Further, the average value of the elevation angle θ is preferably 30 ° or more, more preferably 40 ° or more, and further preferably 50 ° or more.

  In this case, when the length of the line segment connecting the center M1 and the intersection point P is x and the length of the line segment connecting the center M2 or the vertex M3 and the intersection point P is y, tan θ = y / x is 0. The range is from .58 to 1.73. Here, the elevation angle θ is obtained by taking a non-destructive photograph of an internal cross-section of the resin sheet 120 using a three-dimensional measurement X-ray CT apparatus and positioning the center M1 and the center M2 or the vertex M3 with the image analysis apparatus. Is obtained. Simply, the elevation angle θ can be calculated by taking a cross-section in the thickness direction along the longitudinal direction during wet film formation with a scanning electron microscope and determining the center M1 and the center M2 or vertex M3. It is. In addition, the ratio of the bubbles (based on the number of bubbles) is determined by observing a cross section of the polishing pad sheet cut in the thickness direction so that the inclination is confirmed with a scanning electron microscope. Measurement can be performed by processing a photograph (image).

  As described above, the bubble 122b has been described as an example. However, if the elongated portion of the bubble 122 is formed so as to be inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet 120, these matters are described. This is true even if the shape is not like the bubble 122b.

  Note that when the bubble 122 has a shape like the bubble 122b, the stress on the object to be polished can be equalized when pressed during polishing. This is because the length direction of the elongated portion 122a is inclined by 10 to 65 ° in a fixed direction with respect to the in-plane direction of the resin sheet 120, and the shape of the bubble 122b is positioned between the upper elongated portion 122a and the lower portion. This is considered to be because the shape is shifted. Further, it is considered that the diameter of the lower part is larger than that of the upper elongated part 122a. As a result, polishing unevenness of the object to be polished can be suppressed. Regarding this point, it is preferable that the elevation angle θ is in the range of 30 to 60 °, and more preferably 50 to 60 °, because polishing unevenness can be further suppressed.

  The boundary between the skin layer region 120b and the foamed resin region 120c is not always clearly distinguished. For example, the tip of the bubble 122 having the elongated portion 122a of the foamed resin region 120c may extend to the vicinity of the polishing surface. Note that an opening leading to the inside of the resin sheet 120 may appear on the main surface 120 a of the polishing pad sheet 100. Such an opening may be an opening EO in which the bubbles 122 formed in the foamed resin region 120c communicate with the main surface 120a via the skin layer region 120b. However, at least a part thereof is an opening EO in which bubbles 122 formed in the foamed resin region 120c communicate with the main surface 120a via the skin layer region 120b. Such an opening may be formed by a grinding process described later.

  An embossed groove 125 is formed on the main surface 120 a of the resin sheet 120. The grooves formed in the polishing pad are provided to efficiently and surely spread the slurry over the entire surface of the polishing pad and to improve the circulation by polishing, by the CMP method. Is formed. The embossed groove 125 has a wall surface that is hardened by heating at the time of embossing as compared with the groove formed by cutting. Therefore, when the embossed groove 125 is polished with the polishing pad made from the polishing pad sheet 100, the embossed groove 125 is polished. It is difficult for the opening end of the groove and the wall surface to collapse due to the friction between the object and the resin sheet 120.

  Further, when the embossed groove 125 is formed, at least a part of the opening appearing on the main surface of the resin sheet 120 is blocked in the embossed groove 125 due to melting and deformation of the matrix resin accompanying heating and pressing during embossing. Is done. Therefore, the ratio of the number of openings appearing on the main surface 120a to the area of the main surface 120a of the resin sheet 120 is higher than the ratio of the number of openings appearing on the wall surface of the embossed groove 125 to the area of the wall surface of the embossed groove 125. In addition / alternatively, the ratio of the total area of the opening appearing on the main surface 120a to the area of the main surface 120a is higher than the ratio of the total area of the opening appearing on the wall surface of the embossed groove 125 to the area of the wall surface of the embossed groove 125. Become. In addition to / instead, the average diameter of the openings appearing on the main surface 120a relative to the area of the main surface 120a is larger than the average diameter of the openings appearing on the wall surface of the embossed groove 125. As a result, the slurry can be efficiently and surely spread over the entire surface of the polishing pad, and the function of the groove formed in the polishing pad for discharging the slurry containing polishing debris and abrasive grains to the outside of the system can be maintained. The slurry can be reliably held on the polishing surface with which the object comes into contact. When the groove is formed by cutting, an opening appears on the wall surface of the groove to the same extent as the polishing surface. Therefore, compared with the embossed groove 125, the slurry can be efficiently and reliably distributed over the entire surface of the polishing pad, and the outside of the system. The function of the groove to discharge the water is not sufficient.

  Furthermore, the bubble 122 having the elongated portion 122a whose length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet 120 is compared with the case where the bubble does not have such an elongated portion. The wall portion of the matrix resin existing between the bubbles is inclined with respect to the thickness direction of the resin sheet 120. If a groove is formed by cutting the resin sheet 120 in such a state, a part of the inclined wall portion is cut, so when pressed in the thickness direction of the resin sheet 120 during polishing, The wall portion easily collapses, making it difficult to hold the slurry, which is the original function of bubbles. On the other hand, according to the present embodiment, since the embossed groove 125 is formed by melting and deformation of the matrix resin by embossing, the groove is formed without cutting the wall portion existing between the bubbles 122 as compared with the case of cutting. can do. Therefore, although the wall portion between the bubbles 122 is inclined with respect to the thickness direction of the resin sheet 120, it is possible to maintain a high slurry holding capability by the bubbles 122.

  In addition, the bubble 122 having the elongated portion 122a whose length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet 120 is the case where the bubbles are not inclined with respect to the thickness direction of the resin sheet. In comparison, the projected area viewed from the thickness direction of the resin sheet 120 is widened. Therefore, when the groove is formed by cutting, the size of the opening that appears on the wall surface of the groove is larger than that when the bubbles are not inclined, and it becomes difficult to hold the slurry. However, according to the present embodiment, the formation of the embossed groove 125 can suppress the appearance of an opening on the wall surface of the groove, so that the wall portion between the bubbles 122 is inclined with respect to the thickness direction of the resin sheet 120. In spite of this, the holding ability of the slurry by the bubbles 122 can be kept high.

  The open end 125a of the embossed groove 125 has an arc shape in a cross section orthogonal to the length direction. Thus, even if the object to be polished and the resin sheet 120 are rubbed at the time of polishing, the opening end 125a is difficult to collapse, which is preferable. However, the shape is not limited to the arc shape.

  The cross-sectional shape (cross-sectional shape) orthogonal to the length direction of the embossed groove 125 is not particularly limited, and may be an arc shape as shown in FIG. 1, a U shape, a V shape, a rectangular shape, A trapezoidal shape and other polygonal shapes may be used. Further, a pattern in the in-plane direction of the main surface 120a of the resin sheet 120 of the embossed groove 125, that is, an embossed pattern is not particularly limited, and for example, a lattice shape, a radial shape, a concentric circle shape, a spiral shape, and two or more kinds thereof A combination of these may be used. Further, the depth and width of the embossed grooves 125 and the interval (pitch) between the adjacent embossed grooves 125 are not particularly limited, but the viewpoint of ensuring the mechanical strength of the polishing pad and the area of the polishing surface that comes into contact with the object to be polished. In addition, the depth is preferably 0.1 to 1.8 mm and the width is 0.5 to 5.0 mm from the viewpoint of efficiently and reliably spreading the slurry over the entire surface of the polishing pad and discharging the slurry out of the system. It is preferable that the distance is 2.0 to 20 mm. If the depth, width, and interval are within the above ranges, the polishing debris can be discharged more smoothly, and the generation of scratches can be further suppressed.

  The thickness of the resin sheet 120 is not particularly limited, but is preferably 0.3 to 2.1 mm (however, the embossed groove 125 is ignored). When the thickness of the resin sheet is 0.3 mm or more, the life of the polishing pad can be more sufficiently guaranteed, and when the thickness is 2.1 mm or less, an appropriate hardness of the resin sheet 120 can be maintained. The sagging of the outer periphery of the polished article can be prevented more effectively.

From the viewpoint of more effectively and reliably achieving the operational effects of the above-described embodiment, the compression ratio of the resin sheet 120 is preferably 7 to 50%, and more preferably 12 to 20%. From the same viewpoint, the 100% modulus of the resin contained in the resin sheet 120 (preferably, all resins contained in the resin sheet 120) is preferably 2 to 50 MPa, and more preferably 10 to 35 MPa. The compression rate is determined using a shopper type thickness measuring instrument (pressure surface: circle with a diameter of 1 cm) in accordance with Japanese Industrial Standards (JIS L 1021). Specifically, the thickness t1 after pressing for 30 seconds with an initial load is measured, and then the thickness t2 after standing for 5 minutes under the final pressure is measured. From these, the compression ratio is expressed by the following formula:
Compression rate (%) = (t1-t2) / t1 × 100
Calculate from At this time, the initial load is 100 g / cm ² and the final pressure is 1120 g / cm ² . The 100% modulus is the cross-sectional area when the non-foamed resin sheet using the same resin contained in the resin sheet 120 is stretched 100%, that is, when it is stretched twice the original length. Divided value. If the compressibility and 100% modulus are within the above ranges, the object to be polished can be polished more efficiently and with higher quality from the appropriate elastic properties required for the polishing pad.

  Next, the manufacturing method of the polishing pad sheet of this embodiment will be described. In the manufacturing method of the polishing pad sheet of the present embodiment, of the plurality of bubbles 122 appearing in the cross section cut in the thickness direction of the resin sheet 120 so that the inclination is confirmed, the elongated portions 122a of the bubbles 122 of 50% or more are formed. A first step (bubble formation step) in which a plurality of bubbles 122 are formed in the precursor sheet of the resin sheet 120 such that the length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet 120. ) And a second step (groove forming step) for forming the embossed groove 125 on the main surface of the precursor sheet. In addition to those steps, the manufacturing method of the polishing pad sheet of this embodiment is a step of preparing a resin solution containing a resin and a solvent based on a wet film-forming method as shown in FIG. 5 (resin solution preparation). Step), a step of grinding the precursor sheet by buffing processing or slicing processing (grinding step), and a step of bonding the precursor sheet to the base material 110 (base material bonding step), as necessary You may have. Hereinafter, each step will be described.

  First, in the resin solution preparation step provided as necessary, a matrix resin such as the above-mentioned polyurethane resin, a solvent that can dissolve the matrix resin and is mixed with the coagulation liquid described below, and a resin sheet as necessary Other materials to be included in 120 are mixed, and if necessary, defoamed under reduced pressure to prepare a resin solution. Examples of the solvent include N, N-dimethylformamide (hereinafter abbreviated as DMF) and N, N-dimethylacetamide. The viewpoint of ensuring the polishing ability of the resin sheet 120, more sufficiently holding the slurry in the bubbles 122, and the viewpoint of efficiently and reliably forming the bubbles 122 in which the length direction of the elongated portions 122a is inclined as described above. Therefore, the viscosity of the resin solution measured at 25 ° C. using a B-type rotational viscometer is preferably in the range of 3 to 11 Pa · s, and more preferably in the range of 5 to 11 Pa · s. From the viewpoint of obtaining a resin solution in such a numerical range of viscosity, and from the viewpoint of adjusting the coagulation speed described later, for example, the matrix resin is in the range of 10 to 30% by mass, more preferably in the range of 15 to 25% by mass. It may be dissolved in a solvent. Since the viscosity of the resin solution depends on the type and molecular weight of the matrix resin to be used, it is important to select the matrix resin, set the concentration, etc. in consideration of these comprehensively.

  The bubble forming step includes a step of applying the resin solution to the film-forming substrate (application step), a step of coagulating and regenerating the resin in the applied resin solution into a sheet to obtain a precursor sheet (coagulation regeneration step), The step of removing the solvent remaining in the precursor sheet (solvent removal step) is preferably included.

  In the coating step, the resin solution is preferably coated in a sheet form on a belt-shaped film forming substrate using a coating device such as a knife coater, preferably at room temperature. The thickness of the solution to be applied at this time is not particularly limited, but the viewpoint of ensuring the polishing ability of the resin sheet 120 and more sufficiently holding the slurry in the bubbles 122, and the length direction of the elongated portion 122a are described above. From the viewpoint of efficiently and reliably forming the inclined bubbles 122 as described above, the range may be, for example, 0.8 to 1.2 mm. Examples of the substrate for film formation include a resin film such as a PET film, a fabric, and a nonwoven fabric. Among these, a resin film such as a PET film that hardly penetrates the resin solution is preferable.

  In the coagulation regeneration process, the coating film of the resin solution applied to the film-forming substrate is continuously guided into a coagulating liquid whose main component is a poor solvent for the matrix resin (for example, water in the case of a polyurethane resin). In order to adjust the regeneration rate of the matrix resin, an organic solvent such as a polar solvent other than the solvent in the resin solution may be added to the coagulation liquid. The temperature of the coagulation liquid is not particularly limited as long as the matrix resin can be solidified, and may be 15 to 40 ° C., for example, when the matrix resin is a polyurethane resin. In the coagulating liquid, first, a film is formed at the interface between the coating film of the resin solution and the coagulating liquid, and innumerable fine bubbles constituting the skin layer region 120b are formed in the matrix resin immediately adjacent to the film. Thereafter, regeneration of the matrix resin preferably having an open-cell structure proceeds by a cooperative phenomenon of diffusion of the solvent contained in the resin solution into the coagulating liquid and penetration of the poor solvent into the matrix resin. At this time, if the substrate for film formation is difficult to penetrate the coagulation liquid (for example, a film made of PET), substitution of the solvent in the resin solution with the poor solvent occurs preferentially on the skin layer region 120b side, and foaming occurs. Bubbles 122 larger than the skin layer region 120b side are formed on the resin region 120c side.

  Here, the bubble formation accompanying the regeneration of the matrix resin will be described. In the matrix resin, the cohesive force is increased, so that the regeneration rapidly proceeds in the matrix resin closest to the coating, and the skin layer region 120b is formed. The resin in the resin solution rapidly solidifies at the portion in contact with the poor solvent, and a dense skin layer region 120b is formed on the surface, so that mutual diffusion between the solvent and the poor solvent in the resin solution is suppressed. . As a result, the amount of the poor solvent penetrating into the resin solution is reduced, and the regeneration of the matrix resin proceeds slowly. In particular, by adjusting the viscosity of the matrix resin preferably in the above range, the coagulation speed becomes slow, and the regeneration of the matrix resin proceeds more slowly. Further, the difference in viscosity between the skin layer region 120b side to be regenerated first in the coagulation liquid and the incompletely regenerated foamed resin region 120c side is large, and the viscosity of the resin solution is preferably 3 to 11 Pa · s. If the range is adjusted, the difference in the viscosity further increases. As a result, a difference occurs in the fluidity of the resin solution between these portions, so that the lengthwise direction of the elongated portion 122a of the bubble 122 is formed to be inclined. Further, the solvent is removed from the resin solution, that is, by replacing the solvent with the poor solvent, bubbles in the skin layer region 120b and bubbles 122 in the foamed resin region 120c are formed.

  In addition, when the coating film of the resin solution applied to the substrate for film formation is continuously immersed in the coagulating liquid, the conveying speed of the coating film of the resin solution in the coagulating liquid (this conveying speed is the speed of immersing in the coagulating liquid). Is preferably set to 1 to 10 m / min. By adjusting the conveyance speed, it is possible to promote the inclination of the elongated portion 122a of the bubble 122 using the difference in fluidity of the resin solution. In this case, the bubbles 122 are formed so as to be inclined in the length direction (flow direction) of the film-forming substrate. Further, when continuously guiding the coating film of the resin solution applied to the substrate for film formation into the coagulating liquid, it is preferable to guide the coating film in an in-plane direction inclined from the horizontal. Also by this, the inclination of the elongate part 122a of the bubble 122 using the difference in fluidity of the resin solution can be promoted using gravity. In this way, a precursor sheet is obtained. Note that, since the matrix resin is regenerated on the film-forming substrate, the opening of the bubble 122 is not formed on the back surface of the precursor sheet formed in contact with the surface of the film-forming substrate.

  In the solvent removal step, the solvent remaining in the precursor sheet obtained through the coagulation regeneration step is removed. For removing the solvent, a conventionally known water washing treatment can be used. Moreover, you may dry the precursor sheet | seat after removing a solvent as needed. For drying the precursor sheet, for example, a hot air dryer or a cylinder dryer provided with a cylinder having a heat source inside can be used, but the drying method is not limited to this. When a cylinder dryer is used, the precursor sheet is dried by passing along the peripheral surface of the cylinder. Furthermore, you may wind up the obtained precursor sheet | seat in roll shape.

  In the grinding process provided as necessary, the main surface of the precursor sheet on the skin layer region 120b side and the back surface of the foamed resin region 120c side are ground by buff grinding or slicing. Since the thickness of the precursor sheet can be made uniform by the buff grinding process or the slicing process, the pressing force on the object to be polished can be further equalized and the flatness of the object to be polished can be improved. For example, in order to effectively utilize the micro-flatness of the skin layer region 120b and obtain high-precision flatness of the object to be polished, the thickness is made uniform by the grinding process on the back surface side to improve the macro flatness. It may be a precursor sheet. Further, through the grinding process, it becomes easy to form the openings EO of the bubbles 122 on the main surface of the precursor sheet on the skin layer region 120b side, and the average diameter of the openings EO can be adjusted. Thereby, the circulation property of the slurry supplied at the time of a grinding | polishing process can be improved, and the improvement of a polishing rate can be aimed at.

  In the base material bonding step provided as necessary, the base material 110 is bonded to the back side of the precursor sheet. After the adhesive is applied to the surface of the substrate 110 facing the precursor sheet by a conventional method, the precursor sheet and the substrate 110 are pressed against each other, whereby the substrate 110 and the precursor sheet are bonded with the adhesive. A laminated body can be obtained. Examples of the adhesive include heat-sensitive adhesives such as acrylic and nitrile.

  In the groove forming step, an embossed groove 125 is formed on the main surface of the precursor sheet by embossing to obtain the resin sheet 120. First, the laminated body which bonded the base material 110 and the precursor sheet | seat is mounted on the stand which has a flat surface so that the flat surface of the stand and the base material 110 may oppose. At the same time, a mold having a convex portion matched to the emboss pattern is heated. Next, the heated mold is brought into contact with and pressed against the main surface side of the precursor sheet in the laminated body placed on the table. Thereby, the embossed groove | channel 125 is formed in the main surface side of a precursor sheet | seat. In embossing, the embossing mold is usually at a temperature (Tm ± 50) ° C. to (Tg + 100 to Tg + 200) ° C. when the melting point of the matrix resin is Tm (° C.) and the glass transition temperature is Tg (° C.). By applying heat and pressing at a constant pressure for a certain period of time, irregularities are imparted to the polished surface. For example, when the matrix resin is a polyurethane resin, the embossing mold is preferably heated to a temperature of 100 to 180 ° C. and pressed at a pressure of 2.0 to 10.0 MPa for 60 to 300 seconds. In this way, the polishing pad sheet 100 is obtained.

  The manufacturing method of the polishing pad of this embodiment includes the step of forming the polishing pad sheet 100 by the above-described manufacturing method of the polishing pad sheet. For example, the polishing pad of this embodiment can be obtained by cutting the polishing pad sheet 100 obtained as described above into a predetermined shape. Examples of the shape to be cut include a circular shape and a donut shape. Alternatively, the polishing pad sheet 100 may be used as it is as a polishing pad. Furthermore, you may provide another member, such as the below-mentioned adhesive layer and a peeling base material, on the opposite side to the resin sheet 120 with respect to the base material 110 of such a polishing pad. In either case, the main surface side of the polishing pad sheet 100 is the polishing surface of the polishing pad. Preferably, an inspection such as confirming that there is no flaw, dirt, foreign matter or the like is performed until polishing is performed using the obtained polishing pad.

  The polishing method using the polishing pad of the present embodiment includes a step of polishing an object to be polished using the obtained polishing pad. One specific example will be described below. First, an object to be polished is held on a holding surface plate of a single-side polishing machine. Next, the polishing pad is mounted on the polishing surface plate disposed so as to face the holding surface plate. When mounting the polishing pad on the polishing surface plate, if the polishing pad further comprises an adhesive layer and a release substrate from the substrate side, the release substrate is removed to expose the adhesive layer, and then the exposed adhesive The agent layer is brought into contact with the polishing surface plate and pressed. In addition, when the polishing pad is not provided with the adhesive layer, it can also be mounted on the polishing surface plate after applying or attaching the adhesive to the substrate side. Then, a slurry containing abrasive grains (abrasive particles) is circulated and supplied between the object to be polished and the polishing pad, and the object to be polished is pressed against the polishing pad with a predetermined polishing pressure while being held on a polishing platen. By rotating the surface plate, the object to be polished is polished by the CMP method.

  At this time, as shown in FIG. 6, the center of the opening EO that appears on the main surface 120a and the center of the end EC of the bubble 122 opposite to the opening EO are shifted from each other in the thickness direction. When the workpiece 300 is pressed on the polishing pad 200 toward the main surface 120a of the polishing pad 200 and moves in the in-plane direction (arrow direction) of the main surface 120a, the vicinity of the tip of the polishing object 300 in the moving direction When the end portion EC of the bubble 122 is pressed via the opening EO, the opening EO of the bubble 122 having the end portion EC is not easily blocked by the object to be polished. Further, in contrast to the case where the bubbles are not inclined in the longitudinal direction against the elongated portion during polishing, in the present embodiment, the bubbles 122 are inclined in the direction inclined with respect to the longitudinal direction of the elongated portion 122a. Is pressed, the bubble 122 is easily deformed by the pressing, and the volume change of the bubble 122 is increased. Accordingly, the slurry 400 held in the bubbles 122 can be efficiently discharged from the opening EO, and the circulation of the slurry 400 can be promoted.

  Although not shown, the length direction of the elongated portion 122a of the bubble 122 is inclined from the in-plane direction of the resin sheet 120 by 10 to 65 ° in a certain direction and is not inclined in the moving direction of the workpiece 300. For example, when the object to be polished 300 is directly above the periphery of the end portion EC of the polishing pad 200 and a polishing pressure is applied thereto, the bubbles 122 are crushed by the pressure and the slurry contained in the bubbles 122 is stored. 400 is discharged through the opening EO of the bubble 122. On the other hand, when the object to be polished 300 has passed just above the periphery of the end portion EC of the polishing pad 200, the slurry on the polishing pad 200 is released as the bubbles 122 are released from the pressure and return to the original shape. Inhale 400. Thus, since the bubbles 122 function like a pump, the slurry 400 can be held and supplied to the polishing surface more efficiently, and the polishing rate can be increased.

  Further, when the embossed groove 125 is formed, at least a part of the opening appearing on the main surface of the resin sheet 120 is melted and plastically deformed in the embossed groove 125 by heating and pressing in the embossing process. Blocked. Thus, unlike the case where the slurry is taken into the bubbles from the openings remaining in the grooves or newly formed as in the grooves formed by cutting or the like, the slurry 400 is efficiently spread over the entire surface of the polishing pad 200. In addition, the function of the groove formed in the polishing pad 200 for discharging the slurry 400 containing polishing scraps and abrasive grains to the outside of the system can be maintained, and the main surface (polishing surface) 120a with which the object to be polished 300 contacts is maintained. Thus, it is possible to reliably hold the slurry 400. Furthermore, the bubble 122 having the elongated portion 122a whose length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet 120 is compared with the case where the bubble does not have such an elongated portion. The wall portion of the matrix resin existing between the bubbles 122 is inclined with respect to the thickness direction of the resin sheet 120. If a groove is formed by cutting the resin sheet 120 in such a state, a part of the inclined wall portion is cut, so when pressed in the thickness direction of the resin sheet 120 during polishing, The wall portion easily collapses, making it difficult to hold the slurry, which is the original function of bubbles. On the other hand, according to the present embodiment, since the embossed groove 125 is formed by melting and deformation of the matrix resin by embossing, the groove is formed without cutting the wall portion existing between the bubbles 122 as compared with the case of cutting. can do. Therefore, although the wall portion between the bubbles 122 is inclined with respect to the thickness direction of the resin sheet 120, it is possible to maintain a high retention capability of the slurry 400 by the bubbles 122. Further, damage to the object to be polished 300 caused by foreign matter generated by the collapse of the wall portion can be suppressed, and the life of the polishing pad 200 can be extended.

  In addition, the bubble 122 having the elongated portion 122a whose length direction is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet 120 is when the bubbles are not inclined with respect to the thickness direction of the resin sheet 120. As compared with, the projected area as viewed from the thickness direction of the resin sheet 120 becomes wider. Therefore, when the groove is formed by cutting, the size of the opening that appears on the wall surface of the groove is larger than that when the bubbles are not inclined, and it becomes difficult to hold the slurry. However, according to the present embodiment, the formation of the embossed groove 125 can suppress the appearance of an opening on the wall surface of the groove 125, so the wall portion between the bubbles 122 is inclined with respect to the thickness direction of the resin sheet 120. In spite of this, the holding ability of the slurry 400 by the bubbles 122 can be kept high.

  Furthermore, the opening end 125a of the embossed groove 125 is arcuate in a cross section orthogonal to the length direction thereof, so that the object to be polished 300 and the resin sheet 120 are rubbed, or the tip of the object to be polished 300 is opened. Even if it collides with the end 125a or passes while pressing on the opening end 125a, the opening end 125a is difficult to collapse. As a result, it is possible to suppress damage to the object to be polished 300 due to foreign matter generated by the collapse of the open end 125a, and to extend the life of the polishing pad 200.

  The polishing pad of this embodiment is particularly suitably used for finish polishing of semiconductor devices such as magnetic disks, bare silicon, and glass substrates for liquid crystal displays. However, the use of the polishing pad of this embodiment is not limited to them.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to the said this embodiment. The present invention can be variously modified without departing from the gist thereof. For example, in another embodiment of the present invention, the polishing pad may include a substrate for supporting the polishing pad sheet, for example, in addition to the above polishing pad sheet. The base material to support is not specifically limited, The base material with which the conventional polishing pad was equipped may be sufficient. Examples of the material of the base material include polyethylene terephthalate (PET). Moreover, the sheet | seat for polishing pads and polishing pad of this invention may be equipped with the adhesive layer between the base material 110 shown in FIG. Further, the polishing pad sheet and the polishing pad are provided with an adhesive tape (so-called double-sided tape) provided by laminating an adhesive layer and a release substrate on the substrate 110 side, and the adhesive layer facing the substrate 110. You may prepare in this way. The pressure-sensitive adhesive of the pressure-sensitive adhesive layer may be a conventionally known one, and may be a pressure-sensitive type or a heat-sensitive type.

  Further, the polishing pad and the polishing pad sheet may not have the skin layer region 120b in the resin sheet 120. In order to obtain such a polishing pad and a polishing pad sheet, all of the skin layer region 120b may be ground and removed in the grinding step. In this case, since the skin layer region 120b is removed, the opening appearing on the main surface 120a becomes larger than when the skin layer region 120b is provided. Thereby, since the rise time (time until it uses for grinding | polishing processing) is shortened, the efficiency of grinding | polishing processing can be improved more. Moreover, you may provide a grinding process after a groove | channel formation process.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
First, 69 parts by mass of DMF for viscosity adjustment, 7 parts by mass of water, 2 parts by mass of a nonionic surfactant, and 3 parts by mass of carbon black are mixed with 100 parts by mass of a DMF solution of 30% by mass polyester-based polyurethane resin. Thus, a resin solution was prepared. It was 6.4 Pa.s when the viscosity in 25 degreeC was measured using the B-type rotational viscometer (The Toki Sangyo Co., Ltd. make, brand name "TVB-10 type | mold"). Next, a PET film was prepared as a substrate for film formation, and the resin solution was applied thereto using a knife coater to obtain a coating film having a thickness of 1.0 mm.

  Next, the obtained coating film is immersed in a room temperature coagulation bath made of water as a coagulation liquid together with a film forming base material, and the resin is coagulated and regenerated while being conveyed at a conveyance speed of 1.9 m / min. A sheet was obtained. The precursor sheet was taken out from the coagulation bath, and the substrate for film formation was peeled off from the precursor sheet, and then the precursor sheet was immersed in a room temperature cleaning solution (desolvent bath) made of water to remove DMF as a solvent. Thereafter, the precursor sheet was wound up while being dried. The thickness of the obtained precursor sheet was 0.70 mm. Next, the main surface of the precursor sheet was subjected to a buff grinding process to obtain a sheet having a thickness of 0.60 mm.

  After applying the precursor sheet after the buff grinding treatment to a PET film (thickness: 188 μm) as a base material using a gravure roll, the precursor sheet is bonded to the coated surface with a press roll to form a laminate. Obtained. Further, the laminate was dried and wound up.

  Next, the main surface of the precursor sheet of the laminate was embossed. The processing conditions at that time were a processing pressure of 4.5 MPa, a processing (mold) temperature of 160 ° C., and a processing time of 180 seconds. In addition, the embossing pattern is a lattice shape, the cross-sectional shape of the embossed groove is trapezoidal, the opening end is rounded, and the cross-section perpendicular to the length direction of the embossed groove is an arc shape. confirmed. The depth of the embossed groove was 0.40 mm, the width was 2.0 mm, and the interval was 10 mm. Further, the ratio of the openings on the wall surface of the embossed groove was clearly reduced as compared with the surface of other resin sheets. That is, the ratio of the number of openings appearing on the main surface to the area of the main surface of the resin sheet was higher than the ratio of the number of openings appearing on the wall surface of the embossed groove to the area of the wall surface of the embossed groove. Further, the ratio of the total area of the openings appearing on the main surface to the area of the main surface of the resin sheet was higher than the ratio of the total area of the openings appearing on the wall surface of the embossed grooves to the area of the wall surface of the embossed grooves.

  The vicinity of the center in the width direction of the polishing pad sheet thus obtained was cut along the length direction, the resulting cross section was observed with a scanning electron microscope, and a photograph thereof was taken. For the obtained photograph, arbitrarily select 25 or more bubbles, measure the lengthwise inclination and elevation angle θ of the elongated portion with respect to the in-plane direction, and determine the lengthwise inclination of the elongated portion based on the number of bubbles. The ratio of bubbles having a fixed direction of 10 to 65 °, the average value of the elevation angle θ, and the ratio of bubbles having an elevation angle θ of 30 to 60 ° were calculated. Moreover, the compression rate was measured by the above-mentioned method. These results are shown in Table 1.

  The obtained polishing pad sheet was cut out so that the planar shape was a donut shape having an outer diameter of 64.0 cm and an inner diameter of 23.2 cm. The polishing pad was placed at a predetermined position of a polishing machine (9B-5P polishing machine manufactured by Speed Fam Co., Ltd.), and a 95 mmφ hard disk aluminum substrate as an object to be polished was polished under the following conditions.

Polishing conditions and rotation speed: (Surface plate) 30 rpm
Polishing pressure: 90 g / cm ²
Abrasive: Alumina slurry (average particle size: 0.8 μm, pH: 2.3, concentration: 5 mass%)
Abrasive discharge rate: 100 cc / min.
Polishing time: 300 seconds A polishing rate was derived after this polishing process, and it was visually confirmed whether or not scratches had occurred on the surface of the object to be polished. The results are shown in Table 1.

(Example 2)
A polishing pad sheet and a polishing pad were obtained in the same manner as in Example 1 except that a DMF solution of 30% polyether polyurethane resin was used instead of the DMF solution of 30% polyester polyurethane resin. On the wall surface of the embossed groove, the ratio of openings was clearly reduced compared to the surface of other resin sheets. That is, the ratio of the number of openings appearing on the main surface to the area of the main surface of the resin sheet was higher than the ratio of the number of openings appearing on the wall surface of the embossed groove to the area of the wall surface of the embossed groove. Further, the ratio of the total area of the openings appearing on the main surface to the area of the main surface of the resin sheet was higher than the ratio of the total area of the openings appearing on the wall surface of the embossed grooves to the area of the wall surface of the embossed grooves. The results are shown in Table 1.

(Example 3)
A polishing pad sheet and a polishing pad were obtained in the same manner as in Example 1 except that the blending ratio of each component was changed as shown in Table 1. On the wall surface of the embossed groove, the ratio of openings was clearly reduced compared to the surface of other resin sheets. That is, the ratio of the number of openings appearing on the main surface to the area of the main surface of the resin sheet was higher than the ratio of the number of openings appearing on the wall surface of the embossed groove to the area of the wall surface of the embossed groove. Further, the ratio of the total area of the openings appearing on the main surface to the area of the main surface of the resin sheet was higher than the ratio of the total area of the openings appearing on the wall surface of the embossed grooves to the area of the wall surface of the embossed grooves. The results are shown in Table 1.

(Comparative Example 1)
A polishing pad sheet and a polishing pad were obtained in the same manner as in Example 1 except that grooves (cutting grooves: depth 0.40 mm, width 2 mm, interval 20 mm) were formed using cutting instead of embossing. . An opening is formed in the wall surface of the cutting groove, and the ratio of the number of openings appearing on the main surface to the area of the main surface of the resin sheet is the ratio of the number of openings appearing on the wall surface of the cutting groove to the area of the wall surface of the cutting groove. The ratio of the total area of the opening appearing on the main surface to the area of the main surface of the resin sheet was lower than the ratio of the total area of the opening appearing on the wall surface of the cutting groove to the area of the wall surface of the cutting groove . The results are shown in Table 1.

(Comparative Example 2)
Polishing pad sheet in the same manner as in Example 1 except that the blending ratio of each component is changed as shown in Table 1 and the conveyance speed (line speed) is changed from 1.9 m / min to 2.0 m / min. And a polishing pad was obtained. The results are shown in Table 1.

(Comparative Example 3)
Polishing pad sheet as in Comparative Example 1, except that the blending ratio of each component is changed as shown in Table 1 and the conveyance speed (line speed) is changed from 1.9 m / min to 2.0 m / min. And a polishing pad was obtained. The results are shown in Table 1.

(Comparative Example 4)
A polishing pad sheet and a polishing pad were obtained in the same manner as in Example 1 except that the blending ratio of each component was changed as shown in Table 1. The results are shown in Table 1.

  The polishing pad of the present invention is particularly suitably used for finish polishing of semiconductor devices such as magnetic disks, bare silicon, and glass substrates for liquid crystal displays, and has industrial applicability for those uses.

  DESCRIPTION OF SYMBOLS 100 ... Sheet | seat for polishing pads, 110 ... Base material, 120 ... Resin sheet, 120a ... Main surface, 120b ... Skin layer area | region, 120c ... Foamed resin area | region, 122, 122b, 122c, 122d ... Air bubble, 122a ... Elongated part, 125 ... embossing groove, 200 ... polishing pad, 300 ... object to be polished, 400 ... slurry, EO ... opening.

Claims (19)

A polishing pad sheet comprising a resin sheet in which a plurality of bubbles having elongated portions are formed,
Among the plurality of bubbles appearing in a cross section parallel to the thickness direction of the resin sheet, the length direction of the elongated portion in the bubbles of 50% or more on the basis of the number of bubbles is a constant direction with respect to the in-plane direction of the resin sheet 10 to 65 ° is formed so as to be inclined, and the embossed groove on the main surface of the front Symbol resin sheet is formed, and to,
At least some of the bubbles formed on the main surface of the resin sheet so that the length direction of the elongated portion is inclined by 10 to 65 ° in a certain direction with respect to the in-plane direction of the resin sheet. A sheet having a bubble opening .   The sheet according to claim 1, wherein the elongated portion extends from the inside in the thickness direction of the resin sheet toward the main surface.   The ratio of the number of openings appearing on the main surface to the area of the main surface is higher than the ratio of the number of openings appearing on the wall surface of the embossed groove to the area of the wall surface of the embossed groove. Sheet.   The ratio of the total area of the opening that appears on the main surface to the area of the main surface is higher than the ratio of the total area of the opening that appears on the wall surface of the embossed groove with respect to the area of the wall surface of the embossed groove. The sheet | seat of any one of these.   The sheet according to any one of claims 1 to 4, wherein an opening end of the embossed groove has an arc shape in a cross section orthogonal to a length direction of the embossed groove.   Among the plurality of bubbles, 50% or more of the bubbles on the basis of the number of bubbles are in the right triangle whose hypotenuse is a line segment connecting the center M1 of the bubble bottom and the center M2 of the opening appearing on the main surface. 6. The device according to claim 1, wherein the elevation angle θ is in a range of 30 to 60 °, where θ is an elevation angle when the center M <b> 2 is viewed from the center M <b> 1. Sheet.   Among the plurality of bubbles, bubbles of 50% or more on the basis of the number of bubbles are the center M1 in a right triangle whose hypotenuse is a line segment connecting the center M1 of the bubble bottom and the vertex M3 on the main surface side. The sheet according to any one of claims 1 to 5, wherein the elevation angle θ is formed in a range of 30 to 60 °, where θ is an elevation angle when the vertex M3 is viewed from above. .   The said resin sheet is a sheet | seat of any one of Claims 1-7 containing 70 mass% or more of polyurethane resins.   The sheet | seat of any one of Claims 1-8 whose 100% modulus of resin contained in the said resin sheet is 2-50 Mpa.   The sheet according to any one of claims 1 to 9, wherein a compression ratio of the resin sheet is 7 to 50%.   The polishing pad obtained from the sheet | seat for polishing pads of any one of Claims 1-10. It is a manufacturing method of the sheet for polishing pads given in any 1 paragraph of Claims 1-10,
Among the plurality of bubbles appearing in a cross section parallel to the thickness direction of the resin sheet, the length direction of the elongated portion of the bubbles of 50% or more on the basis of the number of bubbles is 10 to 10 in a certain direction with respect to the in-plane direction of the resin sheet. A manufacturing method comprising: a first step of forming a plurality of bubbles in the precursor sheet of the resin sheet so as to be inclined by 65 °; and a second step of forming an embossed groove on a main surface of the precursor sheet. .   In the first step, the precursor sheet is formed by removing the solvent after solidifying and regenerating the resin in the coating film of the resin solution containing the resin and the solvent into a sheet shape. The manufacturing method as described.   In the first step, when the resin in the coating film is solidified and regenerated into a sheet, the bubbles are formed in a state where the in-plane direction of the coating film is inclined from the horizontal. The manufacturing method as described in.   The manufacturing method according to claim 14, wherein the resin contains 70% by mass or more of a polyurethane resin.   The manufacturing method according to any one of claims 12 to 15, further comprising a step of grinding the precursor sheet prior to the second step.   The manufacturing method of a polishing pad which has the process of forming the sheet | seat for polishing pads with the manufacturing method of any one of Claims 12-16.   A polishing method comprising a step of polishing an object to be polished using the polishing pad according to claim 11.   The polishing method according to claim 18, wherein in the step, the object to be polished is polished by chemical mechanical polishing.

Images