JP5172401B2 - Manufacturing method of sheet-like abrasive - Google Patents

Description

  The present invention relates to a method for producing a sheet-like polishing body suitably used for, for example, chamfering of a semiconductor wafer or polishing by a CMP method on the surface.

  In general, in manufacturing a semiconductor element such as an LSI, a manufacturing method is adopted 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, a highly accurate polishing process is efficiently performed by a synergistic effect of chemical polishing with a liquid component and mechanical polishing with loose abrasive grains.

  In the above-described CMP method, polishing is performed while constantly supplying 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, this is the polishing pad described in Patent Document 1. For example, a base material resin such as PES (resin (polyethercarbon resin) or polyvinyl fluoride) is dissolved in a solvent, and a large number of abrasive particles such as silica are mixed with it. In addition, since the base material resin having a critical surface tension in the range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m) is used, the abrasive particles are formed by the base material resin. Since the release is easily held in the continuous mesh airflow, sufficient polishing efficiency and performance can be obtained regardless of the slurry, and the proportion of abrasive particles contributing to polishing of the semiconductor wafer is dramatically increased. The polishing pad is also referred to as a LHA (Loosely Held Abrasive) pad because the abrasive particles are held relatively loosely.
JP 2004-025415 A

  By the way, in the production of the polishing body (LHA pad) used in the conventional CMP method, after being formed into a sheet using a flowable raw material in which abrasive particles are mixed with 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, even when manufactured according to the same process, cracks and undulations that are gentle irregularities on the surface may be formed in the sheet-like abrasive.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a production method that does not cause cracks or undulations in the production of a sheet-like abrasive used for polishing by the CMP method. There is to do.

  As a result of continual research to develop a method for producing such a sheet-like abrasive, the present inventor has dissolved cracks and undulations in the conventional method for producing a sheet-like abrasive described above in the solvent. It was speculated that when the matrix resin gels and separates after separation by solvent separation and simultaneously shrinks and cures, cracking and undulation may occur due to uneven shrinkage. Therefore, the gelation of the matrix resin by the separation of the solvent in the matrix resin is allowed to proceed slowly in the presence of sufficient moisture in the gas, and then the solvent separated in the matrix resin is replaced with water. Three steps of gelation, solvent replacement, and moisture removal, in which a material resin is contracted to form a communication hole for constituting a network structure, and then moisture is removed from the base resin fat by drying. It was thought that the occurrence of the above-mentioned cracks and undulations could be eliminated by applying after forming. The present invention has been made based on such an idea.

  That is, the gist of the invention according to claim 1 for solving the above-described problem is that (a) a base material resin and a large number of abrasive particles are formed into a disk shape and used for polishing by a CMP method. (B) a solution mixing step in which the base resin is dissolved in a solvent and the abrasive particles are mixed to obtain a fluid raw material, and (c) the fluid raw material. Forming a sheet having a predetermined thickness, and (d) a maturing step of gelling the matrix resin by humidifying the sheet-like molded product formed by the forming step with moisture in the gas. (E) replacing the solvent inside the sheet-like molded article that has undergone the aging step with water to remove the solvent from the molded article, and (f) removing the solvent from the molded article, Drying step of drying the sheet-like molded product replaced with The lies in the fact that contain.

  The gist of the invention according to claim 2 is that, in the invention according to claim 1, the aging step is 50 to 95% with respect to the sheet-like molded product formed by the forming step. It is to be humidified with relative humidity.

  The gist of the invention according to claim 3 is that, in the invention according to claim 2, the aging step is 50 to 95% of the sheet-like molded product formed by the forming step. To humidify for 10 to 20 hours at relative humidity

  The gist of the invention according to claim 4 is that, in the invention according to claim 2, the aging step is 70 to 95% of the sheet-like molded product formed by the molding step. The present invention includes a first aging step in which humidification is performed for 1 to 6 hours at a relative humidity, and a second aging step in which the molded product that has undergone the first aging step is kept in a sealed state.

  A gist of the invention according to claim 5 is that, in the invention according to any one of claims 1 to 4, in the solvent removal step, the base material is obtained by immersing the sheet-like molded product in water. The purpose is to shrink the resin.

  Moreover, the gist of the invention according to claim 6 is that, in the invention according to any one of claims 1 to 5, in the drying step, the sheet-like molded product is laminated with a sheet-like water-absorbing material interposed therebetween. It is to be held in the atmosphere in the state.

  The gist of the invention according to claim 7 is that, in the invention according to any one of claims 1 to 6, in the dissolution and mixing step, the volume ratio of abrasive particles to the abrasive is 20 to 50 ( %), The abrasive particles are mixed so as to be within the range.

  The gist of the invention according to claim 8 is that, in the invention according to any one of claims 1 to 7, in the dissolution and mixing step, the weight ratio of the abrasive particles to the abrasive is 51 to 90. The abrasive particles are mixed so as to be in the range of (%).

  According to the method for producing a sheet-shaped abrasive body of the invention according to claim 1, after the base material resin is dissolved in a solvent and the fluid raw material mixed with the abrasive particles is formed into a sheet shape having a predetermined thickness, the sheet The base resin is gelled by humidifying the molded article with moisture in the gas, and then the solvent inside the sheet-like molded article is replaced with water, and the solvent is taken out from the molded article. Since the sheet-shaped molded product in which the solvent is replaced with water is dried, the three-stage process of gelation, solvent replacement, and moisture removal is performed after the molding, so that the shrinkage is performed uniformly. Swelling is preferably eliminated.

  According to the method for manufacturing a sheet-like abrasive body of the invention according to claim 2, the aging step is performed at a relative humidity of 50 to 95% with respect to the sheet-like molded product formed by the forming step. Since the material is humidified, the base material resin after molding is gelled efficiently and uniformly.

  According to the method for producing a sheet-shaped abrasive body of the invention according to claim 3, the aging step is performed at a relative humidity of 50 to 95% with respect to the sheet-shaped molded product molded by the molding step. Since humidification is performed for 10 to 20 hours, when the base resin is, for example, polyvinylidene fluoride, gelation of the base resin after the molding is performed efficiently and uniformly.

  According to the method for producing a sheet-shaped abrasive body of the invention according to claim 4, the aging step is performed at a relative humidity of 70 to 95% with respect to the sheet-shaped molded product molded by the molding step. Since the first aging step for performing humidification for 1 to 6 hours and the second aging step for holding the molded product that has undergone the first aging step in a hermetically sealed state are included, the base resin is, for example, polyether carbon ( In the case of PES) resin or the like, the base resin after the molding is efficiently and uniformly gelled.

  Further, according to the method for producing a sheet-shaped abrasive body of the invention according to claim 5, the solvent removal step is performed by immersing the sheet-shaped molded article in water to shrink the base resin. Since the solvent separated in the base resin is preferably replaced with water and removed from the base resin without using a drying step, cracking due to local shrinkage of the surface due to drying is preferably prevented. . Further, in this solvent removal step, when the base resin is contracted by immersing the sheet-like molded product in water and replacing the solvent in the base resin with water, A plurality of communication holes will be formed, and in the communication holes, the abrasive particles are partly fixed to the inner wall of the communication holes or separated from the base resin in the communication holes. In addition to the fact that the abrasive particles are more easily released from the matrix resin during polishing by the CMP method, a plurality of abrasive particles are suitably dispersed in the communication holes. There is an advantage that high-precision polishing can be performed without causing problems such as scratches.

  Moreover, according to the manufacturing method of the sheet-like abrasive body of the invention according to claim 6, the drying step is to hold the sheet-like molded product in the air in a state where the sheet-like molded article is laminated with the sheet-like water absorbing material interposed therebetween. Therefore, the sheet-like molded product can be dried uniformly and efficiently.

  Moreover, according to the manufacturing method of the sheet-like abrasive | polishing body of the invention concerning Claim 7, as for the said melt-mixing process, the volume ratio with respect to the said abrasive | polishing body of an abrasive particle is in the range of 20-50 (%). Since the abrasive particles are mixed, there is an advantage that the polishing body exhibits a sufficient polishing efficiency and polishing performance in the polishing process by the CPM method and is easy to be molded in the manufacturing. When the volume ratio is less than 20 (%), it is difficult to obtain sufficient polishing efficiency and polishing performance, and when the volume ratio is higher than 50 (%), it is difficult to mold during production.

  Moreover, according to the manufacturing method of the sheet-like abrasive | polishing body of the invention concerning Claim 8, in the said melt mixing process, the weight ratio with respect to the said abrasive | polishing body of the said abrasive particle is in the range of 51-90 (%). Since the abrasive particles are mixed with the abrasive particles, there is an advantage that the abrasive body exhibits sufficient polishing efficiency and performance in the polishing process by the CPM method, and that it is easy to mold during manufacture. When the weight ratio is less than 51 (%), it is difficult to obtain sufficient polishing efficiency and polishing performance, and when the weight ratio is higher than 90 (%), molding becomes difficult at the time of production.

  Preferably, the base resin is polyvinyl fluoride, vinyl fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, vinylidene fluoride / hexafluoropropylene copolymer, polyethylene, polymethyl methacrylate, And at least one of polyether calphone (PES) resin. 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 matrix resin has a critical surface tension within a range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). In this case, since the base resin and the abrasive particles are fixed to each other with a necessary and sufficient bonding force, the abrasive particles are easily released from the base resin during polishing by the CMP method. Free abrasive grains can be suitably supplied between the body and the object to be polished. 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 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.

  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.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  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 material resin 12 and a large number of abrasive particles 14, and is, for example, 300 (mmφ) × t5 (mm). Has dimensions of the degree. 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 matrix resin 12 has its critical surface tension (θ = 0 obtained by extrapolating a straight line obtained by placing various low-molecular liquids on the polymer surface and plotting the contact angle θ and the surface tension γ _L of the liquid. 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, 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 20 to 50 (%), and the weight ratio is in the range of 51 to 90 (%).

  FIG. 2 is a diagram illustrating a state in which the surface of the polishing body 10 of the present embodiment is enlarged by a differential interference microscope. As shown in this figure, the base resin 12 has a fiber shape with an average cross-sectional diameter of about 0.05 (μm), for example, and an average particle diameter is formed in the gap between the fiber base resin 12. A part of the abrasive particles 14 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 area 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 16, it can be said that the abrasive particles 14 are provided in the communication holes 16. The volume ratio of the communication holes 16 to the polishing body 10 is, for example, about 15 to 60 (%).

FIG. 3 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 communication hole 16. Alternatively, it exists in a state separated from the base material resin 12 in the communication hole 16. As described above, in the polishing body 10 of this example, the polishing particles 14 are easily separated from the base material resin 12 during the polishing process by the CMP method described later. The base surface resin 12 has a critical surface tension in the range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m). Since the particles 14 are fixed to each other with a necessary and sufficient bonding force, free abrasive grains, that is, free abrasive particles 14 can be suitably supplied between the polishing body 10 and the object to be polished. That is, in the polishing process by the conventional CMP method, for example, 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.

  4 and 5 are schematic views showing the configuration of the main part of a polishing apparatus 18 by CMP using the polishing body 10 of the present embodiment. 4 is a plan view seen from the axial direction of the polishing surface plate 20, and FIG. 5 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, a work holding member 22 for holding the object to be polished is disposed in the vicinity of the polishing surface plate 20 so as to be rotatable around its axis and movable in the direction of the axis. The work holding member 22 is rotationally driven in one rotation direction indicated by an arrow in the figure by a work drive motor (not shown). The lower surface of the workpiece holding member 22, that is, the surface facing the polishing body 10 is sucked and held by the semiconductor wafer 14 as the object to be polished through the suction layer 24. 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 14 attracted and held by the polishing platen are driven 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 14 is pressed against the polishing body 10. By doing so, the surface to be polished of the semiconductor wafer 14, 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.

  As shown in FIGS. 4 and 5, the polishing apparatus 18 is rotatable about 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. 6 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 material resin 12 is dissolved in a solvent such as DMF (dimethylformamide). That is, for example, the base material resin 12 and its solvent are put 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 is preferably about 1: 4 to 1: 6. Such a solvent functions to improve the moldability in the molding step P3, which will be described later, and functions to form the communication holes 16 in the base material resin 12 in the aging step P4 and the solvent removal step P5. The amount of solvent used is related to the volume ratio of the communication holes 16 in the molded body 10 after molding. If the volume ratio is as described above, the through holes 16 having a volume ratio of about 30 to 40 (%) are formed in the molded abrasive body 10 after molding.

  Next, in the mixing and stirring step P2, the abrasive particles 14 are mixed with the fluid raw material and stirred. For example, it is preferable to use the stirring apparatus used in the dissolving step P1 as it is, and to introduce the abrasive particles 14 into the fluid raw material and mix and stir. Here, it is preferable that the abrasive particles 14 have a volume ratio of 20 to 50 (%) with respect to the abrasive body 10 and a weight ratio of 51 to 90 (%). 14 is set. When the volume ratio of the abrasive particles 14 is less than 20 (%) or the weight ratio is less than 51 (%), it is difficult to obtain sufficient polishing efficiency and performance, and the volume ratio is 50 ( %) Or higher than 90 (%), it becomes difficult to perform molding in the molding step P3 described later.

  In the subsequent molding step P3, the fluid raw material obtained by the melting step P1 and the mixing and stirring step P2 is scraped to a predetermined thickness through a doctor blade, 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.

  In the subsequent ripening step P4, for example, in a relatively sealed environment (sealed 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., The base material contained in the sheet-shaped molded body while suppressing the evaporation of the solvent by holding the sheet-shaped molded body molded in the molding step P3, for example, for 15 to 20 hours, preferably about 18 hours. The resin 12 is slowly precipitated and sufficiently gelled. In the sheet-like molded body, the solvent power of the solvent in the matrix resin 12 is reduced due to the presence of moisture, so that the matrix resin 12 dissolved in the solvent is cured (gelled). The volatilization of the solvent dissolving the matrix resin 12 has the property of promoting the curing (gelation) of the matrix resin 12 in order to increase the concentration in the solvent. 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 this ripening step P4, it is maintained for about 15 to 20 hours in a relatively sealed environment at room temperature that is humidified and controlled to a relative humidity of 50% or more and 95% or less without condensation. When the base resin 12 is exposed to humid air and moisture is supplied to the base resin 12 in the form of atmospheric water vapor, the base resin 12 is uniformly gelled. At this stage, since the base material resin 12 is in a swollen state containing a solvent, the communication hole 16 is 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. Further, since the sealed environment for preventing the volatilization of the solvent dissolving the base material resin 12 is sufficient to maintain the vapor pressure of the solvent in the atmosphere near the sheet-like molded body close to the saturated vapor pressure, In order to maintain the humidified environment, the vicinity of the sheet-like molded body may be covered with a resin sheet, and high airtightness is not required.

  Subsequently, in the solvent removal step P5, the sheet-like molded body in which the base resin 12 is gelated in the aging step P4 is immersed in a water tank, and the solvent in the base resin 12 is replaced with water. The solvent is removed from the base material resin 12. When the solvent is removed in this manner, the base material resin 12 contracts and hardens, and a communication hole 16 is formed in the base material resin 12.

  Then, in the drying step P6, when the sheet-like molded body that has undergone the solvent removal step P5 is alternately laminated with the water-absorbing sheet, the sheet-like molded body is left to stand in a normal temperature atmosphere for about 14 days to be dried. A polishing body 10 of this example having the structure shown in 3 is manufactured.

  As described above, according to the present embodiment, the base material resin 12 is dissolved in a solvent, and the fluid raw material in which the abrasive particles 14 are mixed is formed into a sheet having a predetermined thickness. On the other hand, the matrix resin 12 is gelled by humidifying with moisture in the gas, that is, water vapor, and then the solvent in the sheet-like molded product is replaced with water, and the solvent is taken out from the molded product. Since the base material resin 12 is uniformly shrunk by performing the three-stage process of gelation, solvent replacement, and moisture removal after molding, because the sheet-shaped molded product is replaced with water. Generation | occurrence | production of the crack and the wave | undulation of the sheet-like grinding | polishing body 10 is eliminated suitably.

  Further, according to the present embodiment, the ripening step P4 is to perform humidification for 10 to 20 hours at a relative humidity of 50 to 95% to the sheet-like molded product formed by the forming step P3. Therefore, when the base material resin 12 is particularly polyvinylidene fluoride, the gelation of the base material resin 12 after the molding is performed efficiently and uniformly.

  Further, according to the present example, the solvent removal step P5 is performed by immersing the sheet-like molded product in water to shrink the base material resin 12, and thus the base material resin 12 is not used without using the drying step P6. Since the solvent separated therein is preferably replaced with water and removed out of the base resin 12, cracks due to local shrinkage of the surface due to drying are preferably prevented. In this solvent removal step P5, when the base resin 12 is contracted by immersing the sheet-like molded product in water and replacing the solvent in the base resin 12 with water, the base resin 12, a plurality of communication holes 16 are formed. In the communication holes 16, a part of the abrasive particles 14 are fixed to the inner wall of the communication holes 16 or in the communication holes 16. In addition to the fact that the abrasive particles 14 are more easily separated from the matrix resin 12 during the polishing process by the CMP method, a plurality of abrasive particles 14 are formed in the communication holes 16. Since it is suitably dispersed, there is an advantage that high-precision polishing can be performed without causing defects such as scratches.

  Further, according to the present embodiment, the drying step P6 is to hold the sheet-shaped molded product in the air in a state of being laminated with the sheet-shaped water absorbing material sandwiched therebetween, so that the sheet-shaped molded product is dried. It can be performed uniformly and efficiently.

  Further, according to the present embodiment, the dissolution and mixing steps P1 and P2 mix the abrasive particles 10 so that the volume ratio of the abrasive particles 14 to the abrasive body 10 is in the range of 20 to 50 (%). Therefore, in addition to the polishing body 10 exhibiting sufficient polishing efficiency and polishing performance when polishing by the CPM method, there is an advantage that molding is easy during manufacturing. When the volume ratio is less than 20 (%), it is difficult to obtain sufficient polishing efficiency and polishing performance, and when the volume ratio is higher than 50 (%), it is difficult to mold during production.

  Further, according to the present embodiment, the dissolution and mixing steps P1 and P2 mix the abrasive particles 14 so that the weight ratio of the abrasive particles 14 to the abrasive body 10 is in the range of 51 to 90 (%). Therefore, in addition to the polishing body 10 exhibiting sufficient polishing efficiency and polishing performance when polishing by the CPM method, there is an advantage that molding is easy during manufacturing. When the weight ratio is less than 51 (%), it is difficult to obtain sufficient polishing efficiency and polishing performance, and when the weight ratio is higher than 90 (%), molding becomes difficult at the time of production.

Further, according to this example, the base resin 12 has a critical surface tension in the range of 1.6 × 10 ^{−2 to} 4.0 × 10 ⁻² (N / m), and the base resin 12 And the abrasive particles 14 are firmly fixed to each other with a necessary and sufficient bonding force, so that the abrasive particles 14 are easily separated from the base material resin 12 during the polishing process by the CMP method. The loose abrasive grains can be suitably supplied to the workpiece 32. That is, it is possible to provide a polishing body 10 that is a polishing body that is used for polishing by the CMP method and that exhibits sufficient polishing efficiency and polishing performance regardless of slurry.

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

  In addition, according to this example, the volume ratio of the abrasive particles 14 to the polishing body 10 is in the range of 20 to 50 (%), and the weight ratio is in the range of 51 to 90 (%). In addition to exhibiting sufficient polishing efficiency and polishing performance when the polishing body 10 is polished by the CPM method, the polishing body 10 has an advantage that it can be easily molded.

  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 and excellent in material strength. .

  Further, according to the present embodiment, the abrasive particles 14 contain 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 workpiece 32 which is the polishing body.

  Further, according to the present embodiment, the base resin 12 is dissolved in a solvent in the dissolving step P1 to obtain a fluid material, while the abrasive particles 14 are mixed in the fluid raw material in the mixing and stirring step P2. Then, the flowable raw material containing the abrasive particles 14 thus obtained is poured into a predetermined mold in the subsequent casting molding step P3 and molded, whereby the matrix resin 12 is solidified. The solvent separated from the base resin 12 forms a plurality of communication holes 16 in the base material resin 12, and the abrasive particles 14 are preferably dispersed in the communication holes 16. 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 communication holes 16 and the abrasive particles 14 are provided in the communication holes 16. The polishing body 10 exists in a state where the abrasive particles 14 are partly fixed to the inner wall of the communication hole 16 or separated from the base material resin 12 in the communication hole 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 communication 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.

  Preferably, the weight ratio of the abrasive particles 14 to the polishing body 10 is in the range of 20 to 50 (%) so that the weight ratio is in the range of 51 to 90 (%). Since the abrasive particles 14 are mixed, in addition to the polishing body 10 exhibiting sufficient polishing efficiency and performance when polishing by the CPM method, there is an advantage that the molding is easy in the casting process P3. is there.

  FIG. 7 shows the results of experiments conducted by the inventors. In this experiment, in the manufacturing process shown in FIG. 6, only the relative humidity in the ripening process P4 is 30%, 40%, 45%, 50%, 60%, 75%, 90%, and 100% while maintaining the temperature and time. And the defect rate of the polishing body 10 obtained when the level is changed in 8 stages. The defect rate indicates a rate at which the generated cracks and undulations exceed a preset defect value. If the relative humidity is less than 50%, the rate of failure increases rapidly because the progress of gelation is insufficient. On the other hand, if the relative humidity exceeds 95%, a part where gelation has progressed locally due to moisture due to condensation is formed. As a result, the defect rate increases.

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

  FIG. 8 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 above-described embodiment, but are different in that a polyether calphone (PES) resin is used as the base material resin 12. That is, the base material resin 12 is dissolved in a solvent such as DMF (dimethylformamide), for example, and the abrasive particles 14 are mixed therewith to produce a fluid raw material.

  The flowable raw material obtained by the dissolving step P1 and the mixing and stirring step P2 is in the subsequent forming step P3. After pouring into a circular mold and casting, or after pouring into a circular container, the surface is flattened using a predetermined blade to obtain 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 sealed 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 while the evaporation of the solvent is suppressed, and gels sufficiently and uniformly.

  As in the previous embodiment, in the sheet-like molded body, the solvent power of the solvent in the matrix resin 12 decreases due to the presence of moisture, so that the matrix resin 12 dissolved in the solvent is cured (gel Further, the volatilization of the solvent 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. 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 this ripening process P41 and 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 of 50% or more and 95% or less without condensation. When the base resin 12 is exposed to humid air and moisture is supplied to the base resin 12 in the form of atmospheric water vapor, the base resin 12 is uniformly gelled. At this stage, since the base material resin 12 is in a swollen state containing a solvent, the communication hole 16 is not formed.

  Subsequently, in the solvent removal step P5, the sheet-like molded body in which the base resin 12 is gelated in the aging step P4 is immersed in a water tank, and the solvent in the base resin 12 is replaced with water. The solvent is removed from the base material resin 12. When the solvent is removed in this manner, the base material resin 12 contracts and hardens, and a communication hole 16 is formed in the base material resin 12. Then, in the drying step P6, when the sheet-like molded body that has undergone the solvent removal step P5 is alternately laminated with the water-absorbing sheet, the sheet-like molded body is left to stand in a normal temperature atmosphere for about 14 days. A polishing body 10 of this example having the structure shown in 3 is manufactured.

  According to the present example, similar to the previous example, after the base material resin 12 was dissolved in a solvent and the flowable raw material mixed with the abrasive particles 14 was formed into a sheet having a predetermined thickness, the sheet The molded product is humidified with moisture in the gas, that is, water vapor to gel the base resin 12, and then the solvent in the sheet-shaped molded product is replaced with water, and the solvent is taken out from the molded product. Since the sheet-like molded product in which the internal solvent is replaced with water is dried, the base resin 12 is uniformly shrunk by performing three steps after the molding: gelation, solvent replacement, and moisture removal. Therefore, the occurrence of cracks and undulations in 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 that keeps the molded product that has undergone the first aging step in a sealed state, the base resin is, for example, a polyether calphone (PES) resin. In some cases, the 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 resins in the polishing body of the present invention are in communication with each other, for example. It may be provided with a bubble-shaped communication hole. 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. And the solvent may be mixed and stirred almost simultaneously with the stirring device. Further, the mixing and stirring step P2 is performed before the dissolving step P1, that is, the base resin 12 is a solvent. Prior to dissolution, the abrasive particles 14 may be mixed and stirred in either the base material resin 12 or a solvent.

  In the above-described dissolution step P1, DMF (dimethylformamide) is used as a solvent. However, the solvent may be an organic solvent such as N-methylpyrrolidone, and the base material in the dissolution step P1. There is no limitation on the type as long as the resin 12 is suitably dissolved, a plurality of communication holes 16 are formed in the casting process P3, and can be suitably volatilized in the drying process P4. Further, the above-described casting molding process P3 may be performed by a continuous casting method in which casting is continuously performed on a moving belt.

  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 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. Moreover, the polishing body 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.

  In the above-described embodiment, the polishing body 10 is used for polishing the entire surface of a semiconductor wafer such as a silicon bare wafer or an oxide film silicon wafer. However, the polishing body of the present invention is, for example, a semiconductor wafer. The outer peripheral end face (outer peripheral face) may be used for polishing of various glass substrates for 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.

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

It is a perspective view which shows the polishing tool provided with the grinding | polishing body for grind | polishing the whole surface of a semiconductor wafer manufactured by the manufacturing method of one Example of this invention. 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 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. 5 is a front view of the polishing apparatus shown in FIG. 4. It is process drawing explaining the manufacturing method of the grinding | polishing body shown in FIG. It is a figure which shows the relationship between the relative humidity in the ageing | curing | ripening process of FIG. 6, and the defect rate of a grinding | polishing body. It is process drawing explaining the manufacturing method of the other Example of this invention.

Explanation of symbols

10: Sheet-like polishing body 12: Base material resin 14: Abrasive particles 16: Communication hole P1: Dissolution process, P2: Mixing and stirring process (dissolution and mixing process)
P3: Molding process P4: Aging process P41: First aging process P42: Second aging process P5: Solvent removal process P6: Drying process

Claims (8)

A method for producing a sheet-shaped abrasive body comprising a base material resin and a large number of abrasive particles, formed into a disk shape, and used for polishing by a CMP method,
Dissolving and mixing the base material resin in a solvent and mixing the abrasive particles into a fluid raw material, and
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 substituting the solvent inside the sheet-like molded product that has undergone the aging step with water to take out the solvent from the molded product; and
A drying step of drying the sheet-like molded product in which the solvent in the interior has been replaced with water by the solvent-removing step. 2. The production of a sheet-like abrasive according to claim 1, wherein the aging step humidifies the sheet-like molded product formed by the forming step at a relative humidity of 50 to 95%. Method. 3. The aging step comprises humidifying the sheet-like molded product molded by the molding step at a relative humidity of 50 to 95% for 10 to 20 hours. A method for producing a sheet-like abrasive. The aging step includes
A first aging step of performing humidification for 1 to 6 hours at a relative humidity of 70 to 95% with respect to the sheet-like molded product formed by the forming step;
The manufacturing method of the sheet-like abrasive | polishing body of Claim 2 including the 2nd aging process which hold | maintains the molded article which passed through this 1st aging process in a sealing state. The method for producing a sheet-like abrasive according to any one of claims 1 to 4, wherein the solvent removal step comprises immersing the sheet-like molded product in water to shrink the base material resin. The method for producing a sheet-like abrasive according to any one of claims 1 to 5, wherein in the drying step, the sheet-like molded product is held in the air in a state where the sheet-like water-absorbing material is sandwiched therebetween. . The sheet according to any one of claims 1 to 6, wherein in the dissolution and mixing step, the abrasive particles are mixed so that the volume ratio of the abrasive particles to the abrasive body is within a range of 20 to 50 (%). A method for producing a shaped abrasive body. The said melt | dissolution mixing process mixes the said 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 51-90 (%). A method for producing a sheet-like abrasive.

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