JP2011049256A - Polishing element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing element (LHA pad) which is used for polishing by CMP method, and exhibits proper compressive elasticity for a polishing object by an internally included pore. <P>SOLUTION: This polishing element 10 includes a plurality of communicating pores 16 involving abrasive particles 14 and a plurality of large-sized pores 11 which are parted mutually by the communicating pores 16 and a base material resin 12 and have a cross-sectional area of one cross section larger than the communicating pore 16, in the base material resin 12. Therefore, the polishing element 10 can exhibit the proper compressive elasticity for the polishing object by the large-sized pores 11. For this reason, as compared with a conventional LHA pad not including the large-sized pores 11 but having high hardness, it is possible to reduce an outbreak of an unpolished portion, an outbreak of scratches, and the like in the polishing object upon polishing. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing body suitably used for, for example, chamfering of a semiconductor wafer and polishing processing of the surface by a CMP method and a manufacturing method thereof.

  In general, in the manufacture of a semiconductor element such as an LSI, a manufacturing method is employed in which a large number of chips are formed on a thin disk-shaped semiconductor wafer and cut into each chip size in the final process. Recently, for example, with the improvement of VLSI manufacturing technology, the degree of integration has dramatically improved and the number of wiring layers has been increasing. Therefore, in the process of forming each layer, the entire semiconductor wafer is planarized (global planarization). Is required. One method for realizing the planarization of the entire semiconductor wafer is a polishing method called a CMP (Chemical Mechanical Polishing) method. In this CMP method, a semiconductor wafer is forcibly rotated while being pressed against a polishing pad such as a nonwoven fabric or a foam pad attached on a surface plate, and a slurry containing fine abrasive particles, that is, free abrasive grains (fine powder). However, polishing is performed while supplying a concentrated suspension) dispersed in a liquid such as an alkaline aqueous solution. According to such a CMP method, highly accurate polishing is efficiently performed by a synergistic effect of chemical polishing with a liquid component and mechanical polishing with loose abrasive grains.

  In the CMP method described above, polishing is performed while constantly supplying the slurry to the polishing pad, and the consumption of the slurry containing relatively expensive abrasive particles is increased. Since the used slurry is required to be treated as an industrial waste, it is not preferable from the viewpoint of environmental protection, in addition to a cost that cannot be ignored. In addition, the most cost in the polishing process by the CMP method is the abrasive particles contained in the slurry, and moreover, not all of the abrasive particles contained in the slurry are necessarily involved in the polishing process. Was wasted and was uneconomical.

On the other hand, in order to solve the above-mentioned problems, an abrasive particle fixed type polishing body has been devised for performing polishing by a CMP method without using a slurry. For example, it is a polishing pad (polishing body) described in Patent Document 1. For example, a matrix resin such as polyvinyl fluoride is dissolved in a solvent, and a large number of abrasive particles such as silica are mixed therein, and formed into a disk shape by casting and has a critical surface tension of 1.6 × 10 6. ^{−2 to} 4.0 × 10 ⁻² (N / m) is used as the base material resin, so that the abrasive particles are easily held in the mesh-like continuous air vent formed by the base material resin. Therefore, sufficient polishing efficiency and performance can be obtained regardless of the slurry, and the proportion of abrasive particles contributing to the polishing of the semiconductor wafer can be dramatically increased. The polishing pad is also referred to as an LHA (Loosely Held Abrasive) pad because the abrasive particles are held relatively loosely.

Japanese Patent No. 4266579

  By the way, in manufacturing the polishing body (LHA pad) used in the conventional CMP method, after being formed into a sheet shape using a fluid raw material in which abrasive particles are mixed in a base material resin dissolved in a solvent, In the aging step and / or drying step, the solvent is removed from the fluid raw material to cure the sheet-like abrasive having a predetermined thickness.

  However, depending on the manufacturing method of the above-mentioned polishing body (LHA pad), it is difficult to manufacture the polishing body with a cavity (pore) larger in size than the continuous air holes when the solvent is removed. . For example, it is conceivable to apply a manufacturing method in which bubbles are generated in the flowable raw material and then cured to the abrasive body, but it takes a certain amount of time to be cured after being formed into a sheet. Further, bubbles are unevenly distributed due to the high viscosity of the fluid raw material, and the large cavities cannot be uniformly dispersed in the polishing body. For this reason, the polishing body of Patent Document 1 has a relatively high hardness, and is sufficiently compressed to the polishing body of Patent Document 1 such as a foam pad normally used in the CMP method during polishing. Deformation could not be caused. As a result, an unpolished portion may be generated on the surface of the semiconductor wafer after polishing.

  The present invention has been made against the background of the above circumstances. The object of the present invention is a polishing body (LHA pad) used for polishing by the CMP method. An object of the present invention is to provide a polishing body that exhibits appropriate compression elasticity and a method for producing the same.

  As a result of continual research to develop such an abrasive body and a method for producing the same, the present inventor has obtained water-soluble particles that are not soluble in a solvent but soluble in water in the production process of the abrasive body described in Patent Document 1 described above. Is mixed into the flowable raw material, the solvent is removed while the water-soluble particles are contained, the base resin is cured, and then the water-soluble particles are removed, thereby exhibiting sufficient compression elasticity in the polishing body. It has been found that large pores can be formed. The present invention has been made based on such an idea.

  In order to achieve this object, the gist of the invention according to claim 1 is that (a) polishing that is formed in a disk shape including a base material resin and a large number of abrasive particles and is used for polishing by the CMP method. (B) the abrasive body is separated from each other by a plurality of continuous air holes enclosing the abrasive particles, the continuous air holes and the base material resin, and the cross-sectional area in one cross section is larger than that of the continuous air holes. And providing a plurality of large pores in the base material resin.

  The gist of the invention according to claim 2 is that the average pore diameter of the large pores is in the range of 0.05 to 0.2 (mm), and the volume ratio of the abrasive particles to the abrasive body is It exists in the range of 1-49 (%).

  The gist of the invention according to claim 3 is that the polishing body has a hardness in the range of ASKER C 60 to 95 when the thickness is 4.5 (mm).

Moreover, the gist of the invention according to claim 4 is that the critical surface tension of the base resin is in the range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). There is.

  Moreover, the gist of the invention according to claim 5 is that the weight ratio of the abrasive particles to the abrasive is in the range of 2 to 90 (%).

  In addition, the gist of the invention according to claim 6 is (a) a method of manufacturing a polishing body that is formed in a disk shape and includes a base material resin and a large number of abrasive particles, and is used for polishing by a CMP method. The manufacturing method includes: (b) dissolving the matrix resin in a solvent and not dissolving the solvent in the solvent or having a solubility in the solvent equal to or lower than a predetermined limit and the polishing. A dissolution and mixing step in which particles are mixed to form a flowable raw material; (c) a forming step for forming the flowable raw material into a sheet having a predetermined thickness; and (d) a sheet formed by the forming step. A maturing step of humidifying the molded product with moisture in the gas to gel the base resin, and (e) saturating the solvent in the sheet-shaped molded product that has undergone the maturing step with the water-soluble particles. Replace with aqueous solution Removing the solvent from the molded product, and (f) substituting the water-soluble particles in the sheet-shaped molded product that has undergone the solvent removed process with water to remove the water-soluble particles from the molded product. And a step of removing the water-soluble particles to be removed, and (g) a drying step of drying the sheet-like molded product that has undergone the water-soluble particle removal step.

  The gist of the invention according to claim 7 is that (a) the average particle diameter of the water-soluble particles is in the range of 0.05 to 0.2 (mm), and (b) the dissolution and mixing step. Is that the abrasive particles are mixed so that the volume ratio of the abrasive particles to the abrasive body is in the range of 1 to 49 (%).

  Further, the gist of the invention according to claim 8 is that the melting and mixing step is such that the hardness when the thickness of the polishing body is 4.5 (mm) is in the range of ASKER C 60-95. The water-soluble particles are to be mixed.

  The gist of the invention according to claim 9 is that the solvent is dimethylformamide and the water-soluble particles are composed of sucrose or sodium chloride.

The gist of the invention according to claim 10 is that a critical surface tension of the matrix resin is in a range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). There is.

  The gist of the invention according to claim 11 is that the dissolution and mixing step mixes the abrasive particles so that the weight ratio of the abrasive particles to the abrasive body is in the range of 2 to 90 (%). Is to do.

  According to the invention of claim 1, the abrasive body according to the invention has a plurality of continuous air holes enclosing the abrasive particles, a cross-sectional area in one cross section separated from each other by the continuous air holes and the base material resin. Is provided with a plurality of large pores larger than the continuous air holes in the base material resin, and therefore, the large pores can exhibit an appropriate compressive elasticity against an object to be polished. Compared with a conventional LHA pad having no pores and high hardness, it is possible to reduce the occurrence of unpolished portions and scratches in the object to be polished during polishing. In addition, the polishing body according to the present invention maintains the polishing characteristics of a conventional LHA pad comprising abrasive particles, a base material resin, and continuous air holes. That is, the abrasive particles are partly present in a state of being fixed to the inner wall of the continuous air hole, or are present in a state of being separated from the base material resin in the continuous air hole, and in the polishing process by the CMP method, In addition to the fact that the abrasive particles are more likely to be released from the base resin, a plurality of abrasive particles are suitably dispersed in the continuous air holes, so that high-accuracy polishing is possible without causing defects such as scratches. There is an advantage that processing can be performed.

  According to the invention of claim 2, since the average pore diameter of the large pores is in the range of 0.05 to 0.2 (mm), the large pores are uniformly dispersed, and the large pores are It is possible to reduce unevenness on the surface of the polishing body to reduce damage to the polishing body that may be caused by an object to be polished such as a semiconductor wafer during polishing. Further, since the volume ratio of the abrasive particles to the polishing body is in the range of 1 to 49 (%), the polishing body exhibits sufficient polishing efficiency and performance in polishing processing by the CMP method. There is an advantage that molding is easy in manufacturing. When the average pore diameter of the large pores is less than 0.05 (mm), the large pores are uniformly formed in the polishing body because the particles for forming the large pores are likely to aggregate. It becomes difficult to disperse into. Further, when the average pore diameter of the large pores is larger than 0.2 (mm), the surface of the polishing body is locally scraped, for example, at the outer edge of the semiconductor wafer during polishing, and the polishing body is likely to be damaged. Further, when the volume ratio is less than 1 (%), it is difficult to obtain sufficient polishing efficiency and performance, and when the volume ratio is higher than 49 (%), it is difficult to mold during production. Moreover, when the average pore diameter of the large pores is in the range of 0.05 to 0.2 (mm), assuming that particles satisfying the large pores are used, the average particle diameter of the particles is 0.05. It is in the range of -0.2 (mm).

  According to the invention of claim 3, the polishing body has a hardness in the range of ASKER C 60 to 95 when the thickness is 4.5 (mm), and thus does not include the large pores. Compared with the LHA pad, it is possible to keep the product life without deteriorating the hardness. If the thickness is less than ASKER C 60 when the thickness is 4.5 (mm), the amount of wear of the polishing body is increased during polishing by the CMP method, and the product life is impaired. If the hardness is 4.5 (mm) and exceeds ASKER C 95, the polishing body may be too hard to exhibit sufficient compressive elasticity against the object to be polished.

Moreover, according to the invention which concerns on Claim 4, the critical surface tension of the said base material resin exists in the range of 1.6 * 10 ^<-2 > -4.0 * 10 ^{< -2} > (N / m). Therefore, since the base resin and the abrasive particles are fixed to each other with an appropriate bonding force, the abrasive particles are easily separated from the base resin during the polishing process by the CMP method. The free abrasive grains can be suitably self-supplied between the two. That is, it is possible to provide a polishing body that is used for polishing by the CMP method and that exhibits sufficient polishing efficiency and polishing performance regardless of the supply of slurry. If the base resin has a critical surface tension of less than 1.6 × 10 ⁻² (N / m), the polishing body will easily repel water necessary for polishing by the CMP method, resulting in lower polishing efficiency. If it is higher than 4.0 × 10 ⁻² (N / m), it is difficult to remove the abrasive particles during polishing by the CMP method.

  According to the invention of claim 5, since the weight ratio of the abrasive particles to the polishing body is in the range of 2 to 90 (%), the polishing body has a sufficient polishing efficiency in the polishing process by the CMP method. -In addition to exhibiting polishing performance, there is an advantage that molding is easy in the production. If the weight ratio is less than 2 (%), it is difficult to obtain sufficient polishing efficiency and performance, and if the weight ratio is higher than 90 (%), molding becomes difficult during production.

  According to the invention of claim 6, the method for producing a polishing body according to the invention comprises (a) dissolving the matrix resin in a solvent and not dissolving it in the solvent, or solubility in the solvent. A solution mixing step of mixing the water-soluble particles having a predetermined value below a predetermined limit and the abrasive particles into a fluid raw material; and (b) molding the fluid raw material into a sheet having a predetermined thickness. And (c) an aging step in which the base resin is gelled by humidifying the sheet-like molded product formed by the forming step with moisture in the gas, and (d) the sheet after the aging step. Removing the solvent from the molded product by replacing the solvent inside the molded product with a saturated aqueous solution of the water-soluble particles, and (e) the inside of the sheet-shaped molded product that has undergone the solvent removal step. Of the water-soluble particles A step of removing water-soluble particles by substituting with water to remove the water-soluble particles from the molded product, and (f) a drying step of drying the sheet-like molded product that has undergone the water-soluble particle removal step. . Therefore, by mixing the water-soluble particles together with the abrasive particles in the dissolution and mixing step, it is possible to uniformly disperse the large pores replacing the water-soluble particles together with the abrasive particles inside the abrasive body. Further, since the solvent and water-soluble particles are not simultaneously removed from the inside of the sheet-like molded product, and since the water-soluble particle removing step is provided after the solvent removing step, the matrix resin is in a gel state. In such a case, it is possible to appropriately prevent a problem that the large pores are not sufficiently formed due to removal of water-soluble particles. In addition, the water-soluble particles are not dissolved in the solvent or the solubility in the solvent is not more than a predetermined limit. In short, since the water-soluble particles are hardly dissolved in the solvent, until the previous step of the water-soluble particle removing step. The size of the large pores can be easily set by retaining the original shape and appropriately selecting the average particle diameter of the water-soluble particles. In the solvent removal step, since a saturated aqueous solution of water-soluble particles is used instead of water, the water-soluble particles can remain until the solvent removal step is completed without dissolving the water-soluble particles in the solvent removal step. Is possible. In addition, since the three steps of gelation, solvent and water-soluble particle replacement, and moisture removal are sequentially performed after molding, the shrinkage is uniformly performed, so that the occurrence of cracks and waviness in the polishing body is preferably eliminated. The Further, in the solvent removal step, the base resin shrinks and hardens when the solvent is removed from the gelled base resin, so that the plurality of continuous air holes are cured in the base resin. It is formed with. Since it is ideal that the water-soluble particles do not dissolve in the solvent for the formation of the large pores, the predetermined limit of the solubility is a solubility indicating that the water-soluble particles hardly dissolve in the solvent. Thus, for example, the large pores that replace the water-soluble particles are set so as to have a size enough to cause sufficient compression elasticity in the polishing body. The predetermined thickness is set so that the product thickness of the abrasive body can be realized in consideration of shrinkage of the sheet-like molded product.

  According to the invention of claim 7, since the average particle diameter of the water-soluble particles is in the range of 0.05 to 0.2 (mm), the water-soluble particles are contained in the sheet-like molded product. An object to be polished such as a semiconductor wafer at the time of polishing by reducing the unevenness of the surface of the polishing body due to large pores formed by removing the water-soluble particles in the water-soluble particle removing step, which can be uniformly dispersed It is possible to reduce the damage to the polishing body that can be caused by the above. Moreover, since the said melt | dissolution mixing process mixes the abrasive particle so that the volume ratio with respect to the said abrasive body of the said abrasive particle may be in the range of 1-49 (%), the said abrasive body is based on CMP method. In addition to exhibiting sufficient polishing efficiency and performance in polishing processing, there is an advantage that molding is easy in manufacturing.

  Moreover, according to the invention which concerns on Claim 8, in the said melt | dissolution mixing process, when the thickness of the said grinding | polishing body is 4.5 (mm), the said water | solubilities of the quantity in which the hardness exists in the range of ASKER C 60-95. Since the conductive particles are mixed, it is possible to prevent the product life from being impaired while reducing the hardness of the abrasive body as compared with the conventional LHA pad not provided with the large pores. The larger the mixing amount (volume) of the water-soluble particles with respect to the flowable raw material, the larger the volume ratio of the large pores replaced with the water-soluble particles in the water-soluble particle removal step in the polishing body. The body's hardness is lowered.

  According to the invention according to claim 9, since the solvent is dimethylformamide and the water-soluble particles are composed of sucrose or sodium chloride, the present invention can be applied to the production of a practical LHA pad, The water-soluble particles can be easily obtained at low cost. Further, when the water-soluble particles are sucrose, there is no concern that sodium remains in the polishing body.

Moreover, according to the invention which concerns on Claim 10, the critical surface tension of the said base material resin exists in the range of 1.6 * 10 ^<-2 > -4.0 * 10 ^{< -2} > (N / m). Accordingly, since the base resin and the abrasive particles are fixed to each other with an appropriate bonding force in the polishing body, the polishing particles are easily released from the base resin during the polishing process by the CMP method. The loose abrasive grains can be suitably supplied to the object to be polished. That is, it is possible to manufacture a polishing body that is used for polishing by the CMP method and exhibits sufficient polishing efficiency and polishing performance without depending on the supply of slurry. If the base resin has a critical surface tension of less than 1.6 × 10 ⁻² (N / m), the polishing body will easily repel water necessary for polishing by the CMP method, resulting in lower polishing efficiency. To do. On the other hand, when the particle diameter is higher than 4.0 × 10 ⁻² (N / m), it is difficult to remove the abrasive particles during polishing by the CMP method. In other words, since the critical surface tension of the matrix resin is 4.0 × 10 ⁻² (N / m) or less, the matrix resin shrinks and cures in the solvent removal step, and the continuous air holes are formed. At this time, the abrasive particles are provided in the continuous air holes in a state where they are separated without entering the base resin or are fixed to the base resin so as to be releasably fixed during the polishing process by the CMP method. Thus, a polishing body capable of suitably self-supplying loose abrasive grains is produced.

  According to an eleventh aspect of the invention, the dissolution and mixing step mixes the abrasive particles so that the weight ratio of the abrasive particles to the abrasive body is in the range of 2 to 90 (%). Therefore, in addition to exhibiting sufficient polishing efficiency and polishing performance when the polishing body is polished by the CMP method, there is an advantage that the polishing body is easy to mold during its manufacture.

  Preferably, the base resin is polyvinyl fluoride, vinyl fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, and polymethyl methacrylate. Of which at least one is included. In this way, there is an advantage that a practical polishing body can be provided by a base material resin having a necessary and sufficient critical surface tension and excellent in material strength.

  Preferably, the abrasive particles include at least one of silica, ceria, alumina, zirconia, titania, manganese oxide, barium carbonate, chromium oxide, and iron oxide. In this way, there is an advantage that a practical polishing body can be provided by the abrasive particles having hardness according to the object to be polished.

  Preferably, the water-soluble particles are pulverized particles. In this way, the water-soluble particles are less likely to agglomerate with each other because the surface of the individual particles is non-uniform or irregular as compared to the case of crystal particles, and the water-soluble particles in the sheet-like molded product. It is possible to disperse water-soluble particles more uniformly.

  Preferably, the forming step forms the fluid raw material into a sheet having a predetermined thickness by casting molding in which the fluid raw material is poured into a predetermined mold.

  Preferably, in the aging step, the sheet-like molded product molded in the molding step is humidified at a relative humidity of 50 to 95% for 15 to 20 hours. In this way, when the base resin is, for example, polyvinylidene fluoride, the base resin after the molding is efficiently and uniformly gelled.

  Preferably, in the aging step, (a) the sheet-like molded product molded in the molding step is humidified for 1.5 to 6 hours at a relative humidity of 70 to 95%. 1 aging process and (b) the 2nd aging process which hold | maintains the molded product which passed through the 1st aging process in a sealing state. In this way, when the base material resin is, for example, a polyethersulfone (PES) resin, the base material resin after the molding is efficiently and uniformly gelled.

  Preferably, in the solvent removal step, the base resin is contracted by immersing the sheet-like molded product in a saturated aqueous solution of the water-soluble particles. In this way, the solvent separated in the base resin without using the drying step is preferably replaced with the saturated aqueous solution and removed out of the base resin, so that local shrinkage of the surface due to drying. The crack by is prevented suitably. Further, in this solvent removal step, when the base resin is contracted by immersing the sheet-shaped molded article in the saturated aqueous solution and replacing the solvent in the base resin with the saturated aqueous solution, A plurality of continuous air holes are formed in the material resin, and in the continuous air holes, the abrasive particles are partly fixed to the inner wall of the continuous air holes or in the continuous air holes. In addition to being easily separated from the matrix resin during polishing by the CMP method, a plurality of abrasive particles are suitably dispersed in the continuous air holes. Therefore, there is an advantage that high-precision polishing can be performed without causing defects such as scratches.

  Preferably, the drying step is to hold the sheet-shaped molded product in the air in a state where the sheet-shaped water-absorbing material is sandwiched therebetween, so that the sheet-shaped molded product is uniformly dried. And it can be performed efficiently.

1 is a perspective view showing a sheet-like polishing body that is an embodiment of the present invention and is used for polishing by a CMP method. It is a figure which shows a mode that the surface of the grinding | polishing body shown in FIG. 1 was expanded with the scanning electron microscope. It is a figure which shows a mode that the location A which does not contain a large pore in the surface of the grinding | polishing body shown in FIG. 2 was expanded with the scanning electron microscope at a higher magnification than FIG. It is a figure which expands and shows typically the structure of the grinding | polishing body shown in FIG. It is the top view seen from the axial center direction of the polishing surface plate which shows the principal part structure of the polishing processing apparatus by CMP method in which the polishing body shown in FIG. 1 is used. FIG. 6 is a front view of the polishing apparatus shown in FIG. 5. It is process drawing of 1st Example explaining the manufacturing method of the grinding | polishing body shown in FIG. It is a figure which shows the relationship between the hardness of the grinding | polishing body obtained by the manufacturing method of the grinding | polishing body shown in FIG. 7, and the volume ratio with respect to the grinding | polishing body of the water-soluble particle mixed in the manufacturing process. FIG. 8 is a process diagram of a second embodiment for explaining the method for producing the polishing body shown in FIG. 1, corresponding to FIG. 7.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a perspective view showing a polishing body 10 according to an embodiment of the present invention. As shown in this figure, the polishing body 10 of this example is formed in a disk shape including a base resin 12 and a large number of abrasive particles 14, and has an outer diameter of 300 (mmφ) × thickness of 5, for example. It has dimensions of (mm) t. As will be described later, the polishing body 10 is affixed to a polishing surface plate 20 of a polishing processing apparatus 18 and is used exclusively for polishing by a CMP (Chemical Mechanical Polishing) method.

The base material resin 12 has a critical surface tension γ _CL (an extrapolated straight line obtained by placing various low-molecular liquids on the polymer surface and plotting the contact angle θ and the liquid surface tension γ _L. = 0, that is, a synthetic resin material having a surface tension at cos θ = 1 of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m) is preferably used. That is, the base material resin 12 is made of, for example, polyvinylidene fluoride. However, other resins such as those containing at least one of polyvinyl fluoride, vinyl fluoride / hexafluoropropylene copolymer, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, and polymethyl methacrylate It may be. The polyethylene preferably has a molecular weight of one million or more.

  The abrasive particles 14 preferably have an average particle diameter in the range of 0.005 to 10 (μm). For example, silica is used, but other abrasive particles such as ceria, alumina, zirconia, titania. One containing at least one of manganese oxide, barium carbonate, chromium oxide, and iron oxide may be used. As the silica, for example, fumed silica (silica fine particles obtained by high-temperature combustion of silicon tetrachloride, chlorosilane, etc. in the presence of hydrogen and oxygen) and the like are preferably used. Here, preferably, the volume ratio of the abrasive particles 14 to the polishing body 10 is in the range of 1 to 49 (%), and the weight ratio is in the range of 2 to 90 (%). When the volume ratio is less than 1 (%) or the weight ratio is less than 2 (%), it is difficult to obtain sufficient polishing efficiency and performance, and the volume ratio is more than 49 (%). If it is high or the weight ratio is higher than 90 (%), molding becomes difficult during production. The particle diameter of the abrasive particles 14 is measured by a laser diffraction / scattering method, for example, by a particle diameter / particle size distribution measuring device Microtrac MT3300 manufactured by Nikkiso Co., Ltd. The average particle diameter is the particle diameter. Is the arithmetic mean of The same applies to the particle sizes of the other particles in this example. The particle diameter below the measurement limit of the laser diffraction / scattering method is measured by the dynamic light scattering method using, for example, a particle diameter / particle size distribution measuring device Nanotrac UPA-EX250 manufactured by Nikkiso Co., Ltd.

  2 and 3 are views showing a state in which the surface of the polishing body 10 of the present embodiment is enlarged by a differential interference microscope. FIG. 3 is a view showing a state in which the portion A where the large pores 11 are not included in the surface of the polishing body 10 shown in FIG. 2 is enlarged at a higher magnification than in FIG. As shown in FIG. 2, the large pores 11 are uniformly dispersed on the surface and inside of the polishing body 10. Further, as shown in FIG. 3, the base resin 12 has a fiber shape with an average cross-sectional diameter of about 0.05 (μm), for example, and an average is formed in the gap between the fiber base resin 12 A part of the abrasive particles 14 having a particle diameter of about 0.25 (μm) are fixed to the outer periphery of the matrix resin 12 or separated from the matrix resin 12 in the gap. . That is, the average cross-sectional diameter of the fibrous base material resin 12 is, for example, about 1/10 to 1/3 of the average particle diameter of the abrasive particles 14. Considering such a gap between the fibrous base resin 12 as a plurality of communication holes (communication holes) 16, it can be said that the abrasive particles 14 are provided in the communication holes 16. The volume ratio of the continuous air holes 16 to the polishing body 10 is, for example, about 15 to 60 (%). The hardness of the polishing body 10 of the present embodiment decreases as the volume ratio of the large pores 11 to the polishing body 10 increases. Preferably, the polishing body 10 has a thickness of 4.5 (mm). Is in the range of ASKER C 60-95. This hardness is stipulated in the standard No. SRIS 0101 of the standard (SRIS) of the Japan Rubber Association, and presses the probe of the hardness meter in the thickness direction of the disc-shaped abrasive body 10, that is, in the axial direction. Measured. If the hardness is less than ASKER C 60 when the thickness is 4.5 (mm), the amount of wear of the polishing body 10 is increased during polishing by the CMP method, and the product life is impaired. When the hardness is more than ASKER C 95 when it is .5 (mm), it becomes difficult for the polishing body 10 to be too hard to exhibit sufficient compression elasticity against the object to be polished (object to be polished). There is a risk that the surface pressure is non-uniform to the body.

FIG. 4 is a diagram schematically showing the configuration of the polishing body 10 of the present embodiment. As shown in the drawing, the abrasive particles 14 are partially fixed to the inner wall of the continuous air holes 16. Alternatively, it exists in a state separated from the base material resin 12 in the continuous vent hole 16. That is, as shown in FIGS. 3 and 4, each of the continuous air holes 16 includes the abrasive particles 14 and is formed in the base material resin 12. As shown in FIGS. 2 and 4, a plurality of large pores 11 having a cross-sectional area sufficiently larger than that of the continuous air holes 16 are uniformly separated from each other by the continuous air holes 16 and the base material resin 12. And is provided in the polishing body 10. The continuous air holes 16 and the base resin 12 are formed so as to contact the large pores 11, in other words, surround the large pores 11. As described above, in the polishing body 10 of the present embodiment, the ASKER has a hardness having an appropriate compressive elasticity with respect to the object to be polished by a large number of large pores 11, for example, if the thickness of the polishing body 10 is 4.5 (mm). C The hardness is in the range of 60 to 95. In addition, the polishing particles 14 are easily separated from the base material resin 12 during the polishing process by the CMP method described later. Specifically, the critical surface tension γ _CL of the base resin 12 is in the range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). Since the resin 12 and the abrasive particles 14 are fixed to each other with a necessary and sufficient bonding force, the abrasive body 10 has loose abrasive particles, that is, free abrasive particles 14 between the abrasive body 10 and the object to be polished. It can be suitably self-supplied. That is, in the polishing process by the conventional CMP method, for example, the supply of a slurry containing colloidal silica or the like was indispensable. However, the polishing body 10 of this example does not rely on such a slurry, By supplying a polishing liquid not included, polishing by the CMP method can be performed. Here, the average pore diameter of the large pores 11 is preferably in the range of 0.05 to 0.2 (mm). The particles when the average pore diameter of the large pores 11 in it and in the range of 0.05 to 0.2 (mm), assuming a water-soluble particle PL _WS to particles or later meet the large pores 11 The average particle diameter of (water-soluble particles PL _WS ) is in the range of 0.05 to 0.2 (mm). When the average pore diameter of the large pores 11 is less than 0.05 (mm), the water-soluble particles PL _WS for forming the large pores 11 are likely to aggregate, and the like. Therefore, it is difficult to uniformly disperse the large pores 11, and the amount of water-soluble particles PL _WS used to obtain the desired hardness of the polishing body 10 increases, and the manufacturing cost of the polishing body 10 increases. Further, when the average pore diameter of the large pores 11 is larger than 0.2 (mm), the surface of the polishing body 10 is locally scraped at the outer edge of the semiconductor wafer 26 during the polishing process, and the polishing body 10 is easily damaged. The product life may be shortened, and the surface roughness of the surface of the polishing body 10 is large, so that polishing scraps generated during the polishing process increase and the quality or use feeling of the polishing body 10 as a product is increased. Reduce.

  FIG. 5 and FIG. 6 are schematic diagrams showing the configuration of the main part of a polishing apparatus 18 by CMP using the polishing body 10 of the present embodiment. 5 is a plan view seen from the axial direction of the polishing surface plate 20, and FIG. 6 is a front view. As shown in these drawings, in the polishing apparatus 18, a polishing surface plate 20 is provided in a state of being rotatably supported around its axis, and the polishing surface plate 20 is a surface plate driving motor (not shown). Thus, it is driven to rotate in one rotation direction indicated by an arrow in the figure. The polishing body 10 of this embodiment is affixed to the upper surface of the polishing surface plate 20, that is, the surface against which the object to be polished is pressed. On the other hand, in the vicinity of the polishing surface plate 20, a work holding member 22 for holding an object to be polished (work) is arranged in a state of being supported so as to be rotatable about its axis and movable in the direction of the axis. The workpiece holding member 22 is driven to rotate in one rotation direction indicated by an arrow in the drawing by a workpiece driving motor (not shown). A semiconductor wafer 26 as an object to be polished is adsorbed and held via an adsorption layer 24 on the lower surface of the workpiece holding member 22, that is, the surface facing the polishing body 10. Further, a polishing liquid supply nozzle 28 is disposed in the vicinity of the work holding member 22, and a polishing liquid that is an alkaline or acidic aqueous solution sent from a tank (not shown) is supplied from the polishing liquid supply nozzle 28 during polishing. Is done.

  In the polishing process by the CMP method, the polishing platen 20 and the polishing body 10 attached thereto, the work holding member 22 and the semiconductor wafer 26 held by suction are held by the platen driving motor and the work driving motor. A polishing liquid such as an amine aqueous solution is supplied from the polishing liquid supply nozzle 28 onto the surface of the polishing body 10 while being driven to rotate around the respective shaft centers, and is adsorbed and held by the work holding member 22. The semiconductor wafer 26 is pressed against the polishing body 10. By doing so, the surface to be polished of the semiconductor wafer 26, that is, the surface facing the polishing body 10, is chemically polished by the polishing liquid and mechanically polished by the abrasive particles 14 supplied by the polishing body 10. It is polished flat by the action.

  Further, as shown in FIGS. 5 and 6, the polishing apparatus 18 is rotatable around an axis parallel to the axis of the polishing surface plate 20, and moves in the axial direction and the radial direction of the polishing surface plate 20. An adjustment tool holding member 30 that can be arranged and a polishing body adjustment tool 32 attached to the lower surface of the adjustment tool holding member 30, that is, the surface facing the polishing body 10, are provided. The polishing body adjusting tool 32 attached thereto is pressed against the polishing body 10 while being rotated by an adjusting tool drive motor (not shown), and is reciprocated in the radial direction of the polishing surface plate 20 as necessary. Thus, the polishing body 10 is adjusted and the surface state of the polishing body 10 is maintained in a state suitable for polishing.

  FIG. 7 is a process diagram showing a method for manufacturing the polishing body 10 of this example. Hereinafter, the manufacturing method of the polishing body 10 will be described with reference to this drawing. First, in the dissolving step P1, the base resin 12 is dissolved in a solvent SLV such as DMF (dimethylformamide). That is, for example, the base material resin 12 and the solvent SLV thereof are charged into a stirring device, mixed and stirred while being heated to about 40 to 60 (° C.) to obtain a fluid raw material. Here, the volume ratio of the base material resin 12 and the solvent SLV is preferably about 1: 4 to 1: 6. Such a solvent SLV functions to improve the moldability in the molding step P3, which will be described later, and to form the continuous air holes 16 in the base material resin 12 in the aging step P4 and the solvent removal step P51. The amount of the solvent SLV to be added is related to the volume ratio of the continuous air holes 16 in the molded body 10 after molding. If the volume ratio of the base material resin 12 and the solvent SLV is as described above, the continuous air holes 16 having a volume ratio of about 30 to 40 (%) are formed in the molded body 10 after molding.

Next, in the mixing and stirring step P2, the abrasive particles 14 and the water-soluble particles PL _WS are mixed with the fluid raw material and stirred. For example, it is preferable that the stirring device used in the dissolving step P1 is used as it is, and the abrasive particles 14 and the water-soluble particles _PLWS are put into the fluid raw material and mixed and stirred. Here, it is preferable that the amount of the abrasive particles 14 be charged so that the volume ratio of the abrasive particles 14 to the abrasive body 10 is in the range of 1 to 49 (%) and the weight ratio is in the range of 2 to 90 (%). Is set. Further, preferably, the abrasive particles 14 and the water-soluble particles PL are such that the volume ratio of the sum of the abrasive particles 14 and the water-soluble particles PL _WS to the abrasive body 10 is in the range of 2 to 50 (%). _WS input amount is set. When the volume ratio of the sum of the abrasive particles 14 and the water-soluble particles PL _WS to the abrasive body 10 is higher than 50 (%), molding in the molding step P3 described later becomes difficult. In addition, in order for the water-soluble particles PL _WS to be mixed to contribute to a decrease in the hardness of the polishing body 10, the volume ratio of the water-soluble particles PL _WS to the polishing body 10 is desirably 1% or more, as described above. Since the volume ratio of the abrasive particles 14 to the abrasive body 10 is preferably in the range of 1 to 49 (%), the volume ratio of the sum of the abrasive particles 14 and the water-soluble particles PL _WS to the abrasive body 10 is 2 ( %) Is preferably the lower limit. The dissolution step P1 and the mixing and stirring step P2 correspond to the dissolution and mixing step of the present invention.

Although the water-soluble particles PL _WS are water-soluble, it is desirable that the water-soluble particles PL _WS do not dissolve in the solvent SLV for the formation of the large pores 11. no problem even substantially less in advance experimentally-determined limit of the degree to keep the original shape without a water-soluble particle PL _WS to sexual particle vent step P52 is almost dissolved in the solvent SLV. The water-soluble particle PL _WS is specifically sucrose (sugar, sucrose), but may be a salt such as sodium chloride as long as it is water-soluble. The water-soluble particles PL _WS may be a crystal such as granulated sugar or may be particles finely divided by pulverization treatment such as powdered sugar, but the water-soluble particles PL _WS are uniform without agglomerating the individual water-soluble particles PL _WS. In order to make it disperse | distribute to, the particle | grains atomized by the grinding | pulverization process are better. The average particle diameter of the water-soluble particles PL _WS is preferably in the range of 0.05 to 0.2 (mm), similarly to the range of the average pore diameter of the large pores 11 described above. Further, since the hardness of the as polishing body 10 is larger the volume proportion of abrasive body 10 of the water-soluble particles PL _WS drops, preferably, the applied amount of the water-soluble particles PL _WS in mixing and stirring step P2, the polishing body 10 The hardness when the thickness is 4.5 (mm) is set to be in the range of ASKER C 60-95.

  In the subsequent molding step P3, the flowable raw material obtained by the melting step P1 and the mixing and stirring step P2 is scraped through a doctor blade to a predetermined thickness, or from a long flat nozzle of a T die (flat nozzle type). By being extruded to a predetermined thickness, the sheet is formed on a flat steel flat belt or a flat aluminum alloy forming plate that is moved relative to the doctor blade or the T-die. The predetermined thickness is set so that the product thickness of the polishing body 10 can be realized in consideration of shrinkage due to drying or the like of the sheet-like molded body, for example.

  In the subsequent aging step P4, the base material resin 12 is gelled by humidifying the sheet-like molded body (molded product) formed in the forming step P3 with moisture in the gas. For example, in the molding step P3 in a relatively sealed environment (closed space or sealed container covered with a resin sheet) that is humidified and controlled to a relative humidity in the range of 50 to 95% at room temperature and normal pressure of 20 ° C. By holding the molded sheet-like molded body, for example, for 15 to 20 hours, preferably about 18 hours, the base resin 12 contained in the sheet-like molded body is gently released while suppressing the evaporation of the solvent SLV. To be sufficiently gelled. In the sheet-shaped molded body (hereinafter referred to as “sheet-shaped molded body”), the solubility of the solvent SLV in the matrix resin 12 is reduced due to the presence of moisture, so that the matrix dissolved in the solvent SLV. The resin 12 has a property of curing (gelation), and the volatilization of the solvent SLV dissolving the matrix resin 12 increases the concentration (gelation) of the matrix resin 12 in order to increase the concentration in the solvent SLV. There is a nature to promote. Then, the hardening (gelation) of the base material resin 12 is promoted in the surface layer, tends to be non-uniform gelation as a whole, and causes waviness and cracking of the surface of the polishing body 10. For this reason, in the ripening step P4, the base material is maintained for about 15 to 20 hours in a relatively sealed environment at room temperature that is humidified and controlled at a relative humidity of 50% or more and 95% or less without condensation. When the resin 12 is exposed to humid air and water is supplied to the base resin 12 in the form of water vapor in the air, the base resin 12 is uniformly gelled. At this stage, the base resin 12 is in a swollen state containing the solvent SLV, and therefore the continuous air holes 16 are not formed.

  Here, when the relative humidity exceeds 95%, locally condensed water may come into contact with the sheet-like molded body to cause local curing. If the relative humidity is less than 50%, not only the gelation speed cannot be obtained, but also drying of the surface layer of the sheet-like molded product is promoted, which causes undulation. The normal temperature is not limited to a temperature of about 20 ° C., and may be a temperature in a range of about 15 to 30 ° C. In addition, the sealed environment for preventing the volatilization of the solvent SLV dissolving the base material resin 12 is sufficient to maintain the vapor pressure of the solvent SLV in the atmosphere near the sheet-like molded body close to the saturated vapor pressure. In order to maintain the humidified environment described above, the vicinity of the sheet-like molded body may be covered with a resin sheet, and so high airtightness is not required.

Subsequently, in the solvent removal step P51, the solvent SLV in the sheet-like molded body after the aging step P4 is replaced with a saturated aqueous solution WS _STR of water-soluble particles PL _WS to remove the solvent SLV from the sheet-like molded body. Specifically, the sheet-like molded body in which the base material resin 12 is gelated by the aging step P4 is immersed in a saturated aqueous solution WS _STR of the water-soluble particles PL _WS , and the solvent SLV in the base material resin 12 is dissolved in the water solution. The solvent SLV is removed from the base resin 12 by replacing with a saturated aqueous solution WS _STR of the conductive particles PL _WS . When the solvent SLV is removed in this manner, the base material resin 12 contracts and hardens, and a continuous vent hole 16 is formed in the base material resin 12. The above and saturated aqueous WS _STR of the water-soluble particle PL _WS, since an aqueous solution solvent punching step P51 is dissolved a water-soluble particle PL _WS maximum amount that can be dissolved in an environment that is implemented, the solvent punching step P51 , water-soluble particles PL _WS present as a solid in a sheet-like molded body without dissolving, a solvent SLV is selectively removed from the matrix resin 12.

Subsequently, in the water-soluble particle removal step P52, the water-soluble particles PL _WS inside the sheet-like molded body that has undergone the solvent removal step P51 are replaced with water to remove the water-soluble particles PL _WS from the sheet-like molded body. Specifically, the sheet-like molded body from which the solvent SLV has been removed and the base resin 12 has been shrunk in the solvent removal step P51 is immersed in water, and the water-soluble particles PL _WS inside and on the surface of the sheet-like molded body are removed. By replacing with water, the water-soluble particles _PLWS are removed from the base material resin 12. Thus, when the water-soluble particles PL _WS are removed from the matrix resin 12, the matrix resin 12 does not contract, and the water-soluble particles PL _WS remain in the matrix resin 12 in the shape of the large pores 11 as they are. In place, a large number of large pores 11 having the same shape as each of the large number of water-soluble particles PL _WS are formed. In this water-soluble particle removing step P52, since the continuous air holes 16 have already been formed in the sheet-like molded body in the previous step, water penetrates into the sheet-like molded body through the continuous air holes 16, and the sheet-like molding is performed. Not only the water-soluble particles PL _WS exposed on the surface of the body but also the water-soluble particles PL _WS inside thereof are replaced with water and removed. That is, in the water-soluble particles punching step P52, since the water-soluble particles PL _WS of the sheet-like molded body portion is removed by the presence of interconnected porosity 16, it is possible to obtain a polishing body 10 having a sufficient compressive elasticity. In addition, the solvent removal process P51 and the water-soluble particle removal process P52 are implemented under normal temperature and a normal pressure, for example. The normal pressure is a pressure that is not pressurized or depressurized, and is, for example, about 1 (atm).

  In the drying step P6, for example, the sheet-like molded body that has been subjected to the water-soluble particle removing step P52 is left in the air at room temperature for about 14 days in the state where the water-absorbent sheets are alternately laminated. When the moisture is removed from the substrate and dried, the polishing body 10 of this example having the structure shown in FIGS. 2 to 4 is manufactured.

  As described above, according to the present embodiment, as shown in FIGS. 2 to 4, the abrasive body 10 includes a plurality of continuous air holes 16 including the abrasive particles 14, the continuous air holes 16, the base material resin 12, and the like. Since the matrix resin 12 includes a plurality of large pores 11 that are separated from each other and have a cross-sectional area in one cross section larger than that of the continuous ventilation holes 16, the large pores 11 are suitable for the object to be polished. Compression elasticity can be exerted. Therefore, compared with the conventional LHA pad having no large pores 11 and having high hardness, generation of unpolished portions and generation of scratches in the object to be polished are caused during polishing. It is possible to reduce.

  In addition, according to the present embodiment, preferably, the average pore diameter of the large pores 11 is in the range of 0.05 to 0.2 (mm), so that the large pores 11 are made uniform. It is possible to reduce the unevenness of the surface of the polishing body 10 due to the large pores 11 to reduce damage to the polishing body 10 that may be caused by the object to be polished such as the semiconductor wafer 26 during polishing.

  Moreover, according to the present Example, suitably, the polishing body 10 has a hardness in the range of ASKER C 60 to 95 when the thickness is 4.5 (mm). Compared to a conventional LHA pad that does not include the pores 11, it is possible to prevent the product life from being impaired while maintaining low hardness. In addition, although it states for confirmation, the hardness of the polishing body 10 is defined by a measured value when the thickness of the polishing body 10 is 4.5 (mm). Therefore, it does not mean that the thickness of the polishing body 10 of this embodiment is 4.5 (mm), and the thickness of the polishing body 10 is not limited to 4.5 (mm). Absent.

Further, according to the present embodiment, the solvent SLV used in the manufacturing process of the polishing body 10 shown in FIG. 7 is, for example, DMF (dimethylformamide), and the water-soluble particles PL _WS is sucrose, so the polishing shown in FIG. The manufacturing process of the body 10 can be applied to the manufacture of a practical LHA pad, and the water-soluble particles PL _WS can be obtained inexpensively and easily. In addition, since sucrose does not dissolve in DMF, that is, the water-soluble particles PL _WS does not dissolve in the solvent SLV or the solubility in the solvent SLV is below a predetermined limit, the water-soluble particles PL _WS are shown in FIG. Until the previous step P51 of the water-soluble particle removing step P52 is completed, the original shape is kept, and the size (average pore size) of the large pores 11 is easily set by appropriately selecting the average particle size of the water-soluble particles PL _WS. it can. Further, sucrose because it is water-soluble, in order to remove the water-soluble particles PL _WS water-soluble particles punching step P52, it is possible to use an inexpensive water without the need for special solvents. Further, when the water-soluble particle PL _WS is sucrose, there is no fear that sodium remains in the polishing body 10 as compared with the case where it is sodium chloride.

Further, according to the present embodiment, the water-soluble particles PL _WS are preferably pulverized and finely divided particles rather than crystal particles, and in that case, the water-soluble particles PL _{WS WS,} as compared to the particles of crystal, mutually hardly aggregated for each particle surface is non-uniform or irregular, more uniform dispersion of the water-soluble particles PL _WS in the sheet-form body It is possible to make it.

Further, according to the present example, in the manufacturing process of the polishing body 10 shown in FIG. 7, the fluidity obtained by dissolving the base material resin 12 in the solvent SLV and mixing the abrasive particles 14 with the water-soluble particles PL _WS . After forming the raw material into a sheet having a predetermined thickness, the sheet-shaped molded product (sheet-shaped molded body) is humidified with moisture in the gas, that is, water vapor to gel the base resin 12, and then the sheet The solvent SLV inside the molded product is replaced with a saturated aqueous solution WS _STR of water-soluble particles PL _WS to remove the solvent SLV from the molded product, and the water-soluble particles PL _WS inside the molded product are replaced with water. from the molded product removing water-soluble particles PL _WS, the sheet-like molded article the solvent SLV and water-soluble particles PL _WS is removed from drying, gelling, substitutions of solvents and water-soluble particles, water removal A three-step process is performed sequentially after molding. Therefore, the occurrence of cracks and waviness of the sheet-like polishing body 10 is preferably eliminated.

Further, according to the present embodiment, since the water-soluble particles PL _WS are mixed with the fluid raw material that has undergone the dissolution step P1 in the mixing and stirring step P2 of FIG. 7, the large pores 11 that replace the water-soluble particles PL _WS are polished. It is possible to uniformly disperse inside the polishing body 10 together with the particles 14. In addition, the manufacturing process of the polishing body 10 shown in FIG. 7 does not remove the solvent SLV and the water-soluble particles PL _WS from the inside of the sheet-like molded body at the same time. As shown in FIG. Since the water-soluble particle removing step P52 is provided later, the large pores 11 are not sufficiently formed in the polishing body 10 due to removal of the water-soluble particles PL _WS when the base resin 12 is in a gel form. Defects can be prevented appropriately. Further, the solvent punching step P51, since the saturated aqueous WS _STR of the water-soluble particle PL _WS not used in water, without its solvent punching step P51 is water-soluble particles PL _WS dissolved water soluble particles PL _WS It is possible to leave it up to the conductive particle removing step P52. Further, since the large pores 11 of the abrasive body 10 are formed by removing the water-soluble particles _PLWS with water, for example, compared with the case where pores are formed by burning and removing foamed polystyrene in the sheet-like molded body. Thus, the polishing body 10 can be constituted by the base material resin 12 having a low melting point.

  Further, according to the present embodiment, for example, the ripening step P4 performs humidification for 15 to 20 hours at a relative humidity of 50 to 95% on the sheet-like molded product formed by the forming step P3. Therefore, when the base resin 12 is particularly polyvinylidene fluoride, the base resin 12 after the molding is efficiently and uniformly gelled. When the humidification time exceeds 20 hours, the gelation efficiency of the base resin 12 is deteriorated. When the humidification time is less than 15 hours, the homogeneous gelation of the base resin 12 is hindered.

Further, according to the present embodiment, the solvent removal step P51 is performed by immersing the sheet-shaped molded body in the saturated aqueous solution WS _STR of the water-soluble particles PL _WS to shrink the base material resin 12, and thus the drying step. Since the solvent SLV separated in the matrix resin 12 without using P6 is preferably replaced with the saturated aqueous solution WS _STR of the water-soluble particles PL _WS and removed out of the matrix resin 12, the surface of the surface due to drying is localized. Cracking due to mechanical shrinkage is preferably prevented. Further, in the solvent punching step P51, the solvent SLV of the matrix resin 12 in the sheet-shaped molded body is immersed in a saturated aqueous solution WS _STR of the water-soluble particles PL _WS is a saturated aqueous solution WS _STR of the water-soluble particle PL _WS When the base material resin 12 is contracted by the replacement, a plurality of continuous air holes 16 are formed in the base material resin 12, and the abrasive particles 14 are formed in the continuous air holes 16. In the state where it is fixed to the inner wall of the continuous vent hole 16 in the portion or in a filled state separated from the base resin 12 in the continuous vent 16, and the abrasive particles 14 are separated from the base resin 12 during the polishing process by the CMP method. In addition to being easily separated, a plurality of abrasive particles 14 are preferably dispersed in the continuous air holes 16 so that highly accurate polishing can be performed without causing defects such as scratches. There is an advantage that can be.

Further, according to the present example, in the water-soluble particle removing step P52, the sheet-like molded body is immersed in water, and the water-soluble particles PL _WS in the base material resin 12 are replaced with water. A plurality of large pores 11 are formed in the material resin 12, and each of the plurality of large pores 11 exists in the polishing body 10 with the communication vent 16 and the base material resin 12 as a boundary, Since the polishing body 10 can have an appropriate compressive elasticity during polishing by the CMP method, there is an advantage that high-precision polishing can be performed without causing defects such as unpolished portions.

  In addition, according to the present example, the drying step P6 is to hold the sheet-like molded body that has undergone the water-soluble particle removal step P52 in the air in a state of being laminated with the sheet-like water absorbing material sandwiched therebetween. The sheet-like molded body can be dried uniformly and efficiently.

Further, according to the present example, the critical surface tension γ _CL of the base resin 12 is preferably in the range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). In this case, since the base resin 12 and the abrasive particles 14 are fixed to each other with an appropriate bonding force, the abrasive particles 14 are easily separated from the base resin 12 during the polishing process by the CMP method. The loose abrasive grains can be suitably supplied between the body 10 and the semiconductor wafer 26 as the object to be polished. That is, it is possible to provide a polishing body 10 that is used for polishing by the CMP method and that exhibits sufficient polishing efficiency and polishing performance regardless of the supply of slurry. If the critical surface tension γ _CL of the base resin 12 is less than 1.6 × 10 ⁻² (N / m), the polishing body 10 is likely to repel water necessary for polishing by the CMP method. Efficiency is reduced. On the other hand, when the critical surface tension γ _CL is higher than 4.0 × 10 ⁻² (N / m), it is difficult to separate the abrasive particles 14 during polishing by the CMP method. In other words, when the critical surface tension γ _CL of the base resin 12 is 4.0 × 10 ⁻² (N / m) or less, the base resin 12 shrinks and hardens in the solvent removal step P51 of FIG. When the continuous air holes 16 are formed, the abrasive particles 14 are separated from the base material resin 12 without entering the base material resin 12 or are fixed to the base material resin 12 so as to be releasably fixed during polishing by the CMP method. Therefore, as described above, the polishing body 10 that can suitably supply the free abrasive grains is manufactured.

  Further, according to the present embodiment, the base resin 12 is formed with a plurality of continuous air holes 16, and the abrasive particles 14 are provided in the continuous air holes 16. A part of the abrasive particles 14 are fixed to the inner wall of the continuous air hole 16 or separated from the base resin 12 in the continuous air hole 16, and the polishing is performed in the polishing process by the CMP method. In addition to the particles 14 being more easily released from the base material resin 12, the plurality of abrasive particles 14 are preferably dispersed in the continuous air holes 16, so that high-accuracy polishing without causing problems such as scratches. There is an advantage that processing can be performed.

Further, according to the present embodiment, preferably, the volume ratio of the abrasive particles 14 to the polishing body 10 is in the range of 1 to 49 (%), and the weight ratio is in the range of 2 to 90 (%). . That is, in the mixing and agitation step P2 of FIG. 7, the abrasive particles 14 have a volume ratio of the abrasive particles 14 to the abrasive body 10 in the range of 1 to 49 (%) and a weight ratio of 2 to 90 (%). 14 is mixed with the flowable raw material. In this way, in addition to the polishing body 10 exhibiting sufficient polishing efficiency and performance in polishing processing by the CMP method, there is an advantage that molding is easy in manufacturing. In addition, when the volume ratio of the sum of the abrasive particles 14 and the water-soluble particles PL _WS to the abrasive body 10 is higher than 50 (%) or the weight ratio is higher than 90 (%), the abrasive body 10 is molded when the abrasive body 10 is manufactured. It becomes difficult.

Further, according to this example, the base resin 12 is made of polyvinyl fluoride, vinyl fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, and poly Since it contains at least one of methyl methacrylate, there is an advantage that a practical polishing body 10 can be provided by the base material resin 12 having a necessary and sufficient critical surface tension γ _CL and excellent in material strength. There is.

  In addition, according to the present embodiment, the abrasive particles 14 include at least one of silica, ceria, alumina, zirconia, titania, manganese oxide, barium carbonate, chromium oxide, and iron oxide. There is an advantage that a practical polishing body 10 can be provided by the abrasive particles 14 having hardness corresponding to the object to be polished such as the wafer 26.

Further, in this embodiment, in the molding step P3 of FIG. 7, the sheet-like molded body is molded by being extruded from the long flat nozzle of the T die to a predetermined thickness, etc., but the melting step P1 and the mixing and stirring step P2 The sheet-like molded body may be formed by casting by pouring the fluid raw material obtained in the above into a predetermined mold. For example, the base resin 12 is dissolved in the solvent SLV in the dissolving step P1 to obtain a fluid material, while the abrasive particles 14 and the water-soluble particles PL _WS are used as the fluid material in the mixing and stirring step P2. After mixing and stirring, the fluid raw material containing the abrasive particles 14 and the water-soluble particles PL _WS thus obtained is poured into a predetermined circular mold in the subsequent molding step P3 and molded. By doing so, the solvent SLV separated from the base resin 12 as the base resin 12 solidifies forms a plurality of vent holes 16 in the base resin 12, and the inside of the continuous vent 16 The abrasive particles 14 are preferably dispersed. As a result, it is possible to provide the polishing body 10 in which the base material resin 12 is formed with a plurality of continuous air holes 16 and the abrasive particles 14 are provided in the continuous air holes 16. The abrasive body 10 exists in a state where the abrasive particles 14 are partly fixed to the inner wall of the continuous air vent 16 or separated from the base material resin 12 in the continuous air vent 16. In addition to the abrasive particles 14 being easily separated from the base material resin 12 during the polishing process by the method, a plurality of abrasive particles 14 are suitably dispersed in the continuous air holes 16, thereby causing problems such as scratches. High-precision polishing can be performed without any problems. That is, it is possible to provide a method for manufacturing a polishing body 10 which is a polishing body used for polishing by the CMP method and exhibits sufficient polishing efficiency and polishing performance without depending on a slurry.

FIG. 8 shows the results of an experiment conducted by the present inventors. In the manufacturing process shown in FIG. 7, this experiment is performed by setting the volume ratio of the water-soluble particles PL _{WS to} the abrasive 10, that is, the volume ratio of the water-soluble particles PL _WS to 0%, 10%, 20%, 30%, 40%, % Shows the hardness of the polishing body 10 having a thickness of 4.5 (mm) obtained when it is changed stepwise. If this hardness is in the range of ASKER C 96 to 99, the compression elasticity of the polishing body 10 is extremely insufficient, so that the possibility of generating unpolished portions in the object to be polished during polishing by the CMP method increases. . On the other hand, when the volume ratio of the water-soluble particles PL _WS is 50%, it is difficult to mold the abrasive body 10. From FIG. 8, for example, in order to set the hardness of the polishing body 10 within the range of ASKER C 60 to 95 at a thickness of 4.5 (mm), the volume ratio of the water-soluble particles PL _WS is set to 10 to 48%. It is thought that it is necessary to set the degree. The thickness of the test piece of the polishing body 10 used in this experiment is 4.5 (mm). The experimental results in FIG. 8 are obtained when powdered sugar having an average particle size of 0.17 (mm) produced by pulverizing rock sugar is used as the water-soluble particles PL _WS. The same applies when 0.5 (mm) granulated sugar is used. However, when the granulated sugar having an average particle size of 0.5 (mm) is used as the water-soluble particle PL _WS , the abrasive body 10 is compared with the case where powdered sugar having an average particle size of 0.17 (mm) is used. The result was that the surface was rough and more polishing debris was generated during polishing.

  Next, another embodiment of the present invention will be described. In the following description, parts common to the embodiments are denoted by the same reference numerals and description thereof is omitted.

  FIG. 9 is a process diagram showing another method for manufacturing the polishing body 10. Hereinafter, the manufacturing method of the polishing body 10 will be described with reference to this drawing.

The dissolution step P1 and the mixing and stirring step P2 are the same dissolution, mixing and stirring conditions as in the first embodiment, but differ in that a polyethersulfone (PES) resin is used as the base material resin 12. Yes. That is, the base material resin 12 is dissolved in a solvent SLV such as DMF (dimethylformamide), for example, and the abrasive particles 14 and the water-soluble particles _PLWS are mixed to produce a fluid raw material.

  In the subsequent molding step P3, the flowable raw material obtained by the melting step P1 and the mixing and stirring step P2 is poured into a circular mold and cast, or poured into a circular container. The surface is flattened using a blade of No. 1 to have a uniform thickness. Then, if necessary, vibration is applied or degassed by vacuum.

  Next, the base resin 12 is sufficiently gelled in the first aging step P41 and the second aging step P42. That is, in the first ripening step P41, for example, a relatively sealed environment in which humidification is controlled to a relative humidity in the range of 10 to 95%, preferably in a range of 70 to 95% at room temperature and normal pressure of 20 ° C. In the (closed space or sealed container covered with the resin sheet), the sheet-like molded body molded in the molding step P3 is held, for example, for 1.5 to 6 hours, preferably about 3 hours. In the subsequent second ripening step P42, the sheet-like molded body is covered with a resin sheet and sealed in a container or space, and is held for, for example, 3 days to 2 weeks. As a result, the base material resin 12 contained in the sheet-like molded body is gently precipitated and gelled sufficiently and uniformly while suppressing the evaporation of the solvent SLV.

  Similar to the above-described embodiment, in the sheet-like molded body, the solvent SLV dissolves in the matrix resin 12 due to the presence of moisture, so that the matrix resin 12 dissolved in the solvent SLV is cured. In addition, the volatilization of the solvent SLV dissolving the base resin 12 has the property of promoting the hardening (gelation) of the base resin 12 in order to increase the concentration in the solvent SLV. is there. Then, the hardening (gelation) of the base material resin 12 is promoted in the surface layer, tends to be non-uniform gelation as a whole, and causes waviness and cracking of the surface of the polishing body 10. For this reason, in the first ripening step P41 and the second ripening step P42, it is maintained for about 72 hours in a relatively sealed environment at room temperature that is humidified and controlled to a relative humidity in the range of 95% or less with 50% or more and no condensation. Thus, the base material resin 12 is exposed to humid air, and the base material resin 12 is uniformly gelled by supplying water to the base material resin 12 in the form of atmospheric water vapor. At this stage, the base resin 12 is in a swollen state containing the solvent SLV, and therefore the continuous air holes 16 are not formed.

  The subsequent solvent removal step P51, water-soluble particle removal step P52, and drying step P6 are the same as in the first embodiment.

According to the present embodiment, as in the first embodiment described above, in the manufacturing process of the polishing body 10 shown in FIG. 9, the base resin 12 is dissolved in the solvent SLV, and the abrasive particles 14 and the water-soluble particles are dissolved therein. After the fluid raw material mixed with PL _WS is formed into a sheet having a predetermined thickness, the base resin 12 is obtained by humidifying the sheet-shaped molded product (sheet-shaped molded body) with moisture in the gas, that is, water vapor. Then, the solvent SLV inside the sheet-like molded article is replaced with a saturated aqueous solution WS _STR of the water-soluble particles PL _WS to remove the solvent SLV from the inside of the molded article, and the water-soluble particles PL inside the molded article _{Since the WS} is replaced with water to remove the water-soluble particles PL _WS from the molded product, and the sheet-shaped molded product from which the solvent SLV and the water-soluble particles PL _WS are removed is dried. The three-step process of replacing the conductive particles and removing water Since the shrinkage is uniformly performed by the sequential application after forming, the occurrence of cracks and waviness of the sheet-like polishing body 10 is preferably eliminated.

  Further, according to the present embodiment, in the aging step, the sheet-like molded product formed in the forming step P3 is preferably humidified for 1.5 to 6 hours at a relative humidity of 70 to 95%. Since the first aging step P41 and the second aging step P42 for keeping the molded product that has undergone the first aging step in a sealed state, the base resin 12 is, for example, a polyethersulfone (PES) resin. In this case, gelation of the base resin 12 after the molding is performed efficiently and uniformly.

  As mentioned above, although the suitable Example of this invention was described in detail based on drawing, this invention is not limited to this, Furthermore, it implements in another aspect.

  For example, in the above-described embodiment, the base resin 12 has a fibrous shape, but this is only a preferred form of the present invention, and the base resin 12 in the polishing body 10 of the present invention is, for example, You may provide the bubble-shaped continuous ventilation hole 16 connected mutually. That is, the mode is not particularly limited as long as the free abrasive grains can be suitably supplied in the polishing process by the CMP method.

In the embodiment described above, the mixing and stirring step P2 is performed subsequent to the dissolving step P1, but is performed substantially simultaneously with the dissolving step P1, that is, the base resin 12 and the abrasive particles 14. In addition, the water-soluble particles PL _WS and the solvent SLV may be charged into the stirring device almost simultaneously and mixed and stirred. Further, the mixing and stirring step P2 is performed prior to the dissolving step P1, that is, Prior to the base resin 12 being dissolved in the solvent SLV, the abrasive particles 14 and the water-soluble particles PL _WS are mixed and stirred in either the base resin 12 or the solvent SLV. It doesn't matter.

Further, in the above-described dissolution step P1, DMF (dimethylformamide) was used as the solvent SLV. However, the solvent SLV may be an organic solvent such as N-methylpyrrolidone. The base resin 12 is preferably dissolved, the water-soluble particles PL _WS are not dissolved at all or hardly dissolved, the plurality of continuous air holes 16 are formed in the molding step P3, and volatilized suitably in the drying step P4. The type is not limited as long as it can be obtained.

  In the above-described embodiment, an alkaline aqueous solution not containing free abrasive grains is used as the polishing liquid in the polishing process by the CMP method using the polishing body 10, but for example, by the CMP method using slurry. Even if the polishing body 10 of the present invention is used for polishing, it does not matter. Even in such a case, sufficient polishing efficiency and polishing performance can be obtained with a slurry containing a few loose abrasive grains, or superior polishing efficiency and polishing compared to conventional polishing processes using polishing pads and slurries. The effect of showing performance etc. can be expected. In addition, the polishing body 10 of the present invention may be used for polishing processing using a neutral liquid such as pure water as a polishing liquid, and can be applied to polishing processing in a wide variety of modes.

  Further, in the above-described embodiment, the polishing body 10 is used for polishing the entire surface of the semiconductor wafer 26 such as a silicon bare wafer or an oxide film silicon wafer. You may use for the grinding | polishing process etc. of the outer peripheral end surface (outer peripheral surface) of the semiconductor wafer 26, the glass substrate for various electronic devices. That is, the type of the object to be polished is not limited as long as the effects of the present invention can be enjoyed.

  In the above-described embodiment, the average pore diameter of the large pores 11 is determined using an appropriate measurement method such as a mercury intrusion method using, for example, a pore distribution measuring device Autopore IV-9520 manufactured by Shimadzu Corporation. The arithmetic average of the measured pore diameters can be used.

  Although not exemplified one by one, the present invention is used with various modifications within the scope not departing from the gist thereof.

10: Polishing body 11: Large pores 12: Base material resin 14: Abrasive particles 16: Continuous vent P1: Dissolution process (dissolution and mixing process)
P2: Mixing and stirring step (dissolving and mixing step)
P3: Molding process P4: Aging process P51: Solvent removal process P52: Water-soluble particle removal process P6: Drying process

Claims (11)

A polishing body that is formed into a disk shape with a base material resin and a large number of abrasive particles, and is used for polishing by the CMP method,
A plurality of continuous air holes enclosing the abrasive particles, and a plurality of large pores separated from each other by the continuous air holes and the base material resin and having a cross-sectional area in one cross section larger than the continuous air holes. A polishing body characterized by comprising the inside. The average pore diameter of the large pores is in the range of 0.05 to 0.2 (mm), and the volume ratio of the abrasive particles to the polishing body is in the range of 1 to 49 (%). The polishing body according to claim 1. The polishing body according to claim 1 or 2, wherein the polishing body has a hardness in the range of ASKER C 60 to 95 when the thickness is 4.5 (mm). 4. The critical surface tension of the base resin is in a range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). 5. The polishing body according to 1. The abrasive body according to any one of claims 1 to 4, wherein a weight ratio of the abrasive particles to the abrasive body is in a range of 2 to 90 (%). A method for producing a polishing body comprising a base material resin and a large number of abrasive particles and formed into a disk shape and used for polishing by a CMP method,
Dissolving the matrix resin in a solvent, and mixing the water-soluble particles that do not dissolve in the solvent or have a solubility in the solvent equal to or lower than a predetermined limit with the abrasive particles, Dissolving and mixing step,
A molding step of molding the fluid raw material into a sheet having a predetermined thickness;
A maturing step of gelling the matrix resin by humidifying with moisture in the gas for the sheet-like molded product molded by the molding step,
A solvent removal step of replacing the solvent inside the sheet-like molded product that has undergone the aging step with a saturated aqueous solution of the water-soluble particles to remove the solvent from the molded product;
A water-soluble particle removing step of substituting the water-soluble particles inside the sheet-like molded product that has undergone the solvent removal step with water to remove the water-soluble particles from the molded product; and
A drying step of drying the sheet-like molded product that has undergone the water-soluble particle removal step. The average particle diameter of the water-soluble particles is in the range of 0.05 to 0.2 (mm),
The method for producing an abrasive body according to claim 6, wherein the dissolving and mixing step mixes the abrasive particles such that a volume ratio of the abrasive particles to the abrasive body is in a range of 1 to 49 (%). . The dissolution and mixing step is to mix the water-soluble particles in an amount such that the hardness when the thickness of the polishing body is 4.5 (mm) is in the range of ASKER C 60-95. 8. A method for producing an abrasive body according to 7. The method for producing a polishing body according to any one of claims 6 to 8, wherein the solvent is dimethylformamide, and the water-soluble particles are composed of sucrose or sodium chloride. 10. The critical surface tension of the base resin is in a range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). 10. The manufacturing method of the abrasive | polishing body as described in any one of. The said dissolution mixing process mixes this abrasive particle so that the weight ratio with respect to the said grinding | polishing body of the said abrasive particle may exist in the range of 2-90 (%). The manufacturing method of the grinding | polishing body of description.

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