JP4695236B2 - Manufacturing method of CMP conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a CMP conditioner and a manufacturing method thereof. More specifically, the present invention can easily adjust the protruding amount of abrasive grains, and contaminates the polishing pad with metal during conditioning of a polishing pad for chemical mechanical polishing such as an interlayer insulating film of a semiconductor device or a metal wiring. The present invention relates to a CMP conditioner and a method for manufacturing the CMP conditioner that do not cause a risk of damaging the wafer surface due to falling off of abrasive grains.
[0002]
[Prior art]
Multilayer interconnects are becoming increasingly important for high integration and high speed of VLSI, and there is a demand for further advancement in the flattening process of interlayer insulating films and metal interconnects that form the core of this technology. In general, in a wafer processing apparatus for polishing the surface of a semiconductor wafer, a polishing pad is attached to a disk-shaped surface plate, one or more wafers are placed on the upper surface of the surface plate, and these wafers are placed on the polishing pad. Chemical mechanical polishing (CMP) is performed by chemical and mechanical action of an interface by supplying a polishing liquid containing fine abrasive particles between a polishing pad and a wafer while forcibly rotating by a carrier.
As the polishing pad, a velor type pad in which a polyester nonwoven fabric is impregnated with polyurethane resin, a suede type pad in which a polyester nonwoven fabric is used as a base material and a foamed polyurethane layer is formed thereon, or a foamed polyurethane pad having closed cells is used. ing. Also, as the abrasive particles, ferrite powder, alumina powder, barium carbonate, colloidal silica, cerium oxide, etc. are used, and as the polishing liquid, potassium hydroxide solution, dilute hydrochloric acid, dilute nitric acid, hydrogen peroxide solution, iron nitrate solution etc. are used. used. While such wafer polishing is repeated, chips or abrasive particles of the work material enter the fine holes of the polishing pad, causing clogging, or the surface of the polishing pad due to the chemical reaction heat between the abrasive particles and the wafer. Becomes a mirror surface, and the polishing rate decreases. For this reason, it is necessary to condition the polishing pad constantly or periodically.
However, in the conditioner with the abrasive grains fixed by the conventional electrodeposition method, the abrasive grains are not completely one layer, and there are always abrasive grains sandwiched between the abrasive grains, which fall off and are polished. There was a problem of remaining on the pad and damaging the wafer surface. In conditioners with metal grains fixed by metal bonds, copper and the like are eluted by highly reactive polishing liquids, and nickel and the like remain in the polishing pad. However, since it adheres on the wafer which is a workpiece, the cleaning process of the wafer after chemical mechanical polishing is very troublesome. Furthermore, in both the electrodeposition type and the metal bond type, it is very difficult to adjust the protruding amount of diamond abrasive grains, and there is a problem that it takes a long processing time to set the protruding amount of diamond abrasive grains to a desired value. .
Various methods have been taken to prevent the abrasive grains from falling from the conditioner and the elution of metal. For example, in Japanese Patent Laid-Open No. 2-225825, an abrasive layer is formed by temporarily fixing a single abrasive grain on the inner surface of an inversion type by electrodeposition, and embedding and fixing the temporarily fixed abrasive with metal or resin. In addition, a conditioner that is manufactured by joining a base metal to the abrasive layer and removing the reversal mold, where the most protruding parts of the abrasive grains are all on the same plane, has been proposed. ing. In Japanese Patent Laid-Open No. 10-15819, a single layer of abrasive grains is temporarily fixed to a base metal by plating, the floating stones of the temporarily fixed abrasive grains are removed with a grinding stone, and plating is performed until the abrasive grains are embedded. There has been proposed a conditioner in which the most protruding portion is exposed so that the protruding amount of the abrasive grains is 5 to 30% of the average particle diameter by performing the quarrying process, and there is no fear of dropping off the abrasive grains. Japanese Patent Laid-Open No. 10-249708 discloses a method in which an abrasive grain is fixed to a base metal from a brazing material to form an abrasive grain layer, and then the abrasive grain layer is covered with a synthetic resin layer so that no metal is exposed on the surface. In addition, there has been proposed a conditioner that does not cause the abrasive grains to fall off and the metal to elute. Furthermore, JP-A-11-33911 discloses that an abrasive grain is fixed to a base metal by plating to form an abrasive grain layer, and the abrasive grain layer is covered with a synthetic resin layer, and then the surface portion of the synthetic resin layer is removed. Then, a conditioner has been proposed in which the tip of the abrasive grains protrudes from the synthetic resin layer and the plated metal is not exposed by being covered with the synthetic resin layer, and there is no risk of abrasive grains falling off and metal elution. . However, all of these conditioners are inevitably costly due to the long manufacturing process, and even if they are covered with a synthetic resin layer, as long as a metal material is used, the conditioner is completely free from metal elution. Anxiety could not be wiped out.
Japanese Patent Laid-Open No. 9-323255 discloses a polishing base polishing grit machine for a chemical machine polisher device in which grit is not peeled off from a base, and a flat base made of resin and polishing evenly distributed on the base There has been proposed an abrasive grit machine comprising an adhesive grit and an adhesive having resistance to a chemical abrasive that adheres the grit to a base. This polishing grit machine has no metal as a constituent material, so there is no risk of metal elution, but since the grit is bonded to the base using an adhesive, the grit may fall off during polishing. . For this reason, there has been a demand for a CMP conditioner that can be easily and easily manufactured without the risk of abrasive grains falling off and metal elution.
[0003]
[Problems to be solved by the invention]
The present invention can easily adjust the protruding amount of abrasive grains, and there is no risk of contamination of the polishing pad with metal when conditioning a polishing pad for chemical mechanical polishing such as an interlayer insulating film of a semiconductor device, metal wiring, etc. An object of the present invention is to provide a CMP conditioner and a method for manufacturing the CMP conditioner which does not damage the wafer surface due to falling off of abrasive grains.
[0004]
[Means for Solving the Problems]
As a result of intensive research to solve the above problems, the present inventors have found that the CMP conditioner in which the substrate is formed of a synthetic resin has no risk of metal elution and is provided on the surface of the mother die. The CMP conditioner can be easily manufactured by fitting abrasive grains into the holes, filling the matrix with synthetic resin and forming the shape of the substrate, and fixing the abrasive grains to the substrate. As a result, the present invention has been completed based on this finding.
That is, the present invention
(1) a substrate having an abrasive layer made of abrasive grains protruding from the abrasive layer plane on the surface, pressing heated with abrasive grain layer consisting of abrasive grains projecting having no synthetic resin composition part and abrasive made of metal a synthetic resin substrate formed by molding, thereby forming the shape of the substrate of CMP conditioner by pressing hot forming together with the abrasive grain layer consisting of abrasive grains projecting the synthetic resin composition, the molded synthetic resin abrasives A method of manufacturing a CMP conditioner, characterized in that it protrudes and adheres to the surface of the abrasive layer of the substrate,
(2) The process for producing a CMP conditioner according to item (1), wherein the synthetic resin composition contains a fibrous nonmetallic material or ceramic powder, calcium carbonate, kaolin, or mica powdered nonmetallic material. ,
(3) The method for producing a CMP conditioner according to item (1) or (2), wherein the abrasive grains are square columnar diamonds having a square cross section ; and
(4) A synthetic resin substrate formed by a synthetic resin composition in which a substrate having an abrasive layer on its surface does not have a metal portion, and the synthetic resin composition is molded into the shape of the substrate by heating and pressing. And a CMP conditioner manufacturing method in which abrasive grains are projected and fixed on the surface of a molded synthetic resin substrate, and the abrasive grains are fitted into holes of a certain depth provided on the surface of the mother die, and are cylindrical. The synthetic resin composition is filled into the space formed by fitting the outer mold of the mold to the mother mold and heated while being pressed using a push punch, thereby forming the synthetic resin composition into the shape of the substrate. The abrasive grains are fixed at a protrusion amount corresponding to the depth of the hole and fixed so that the protrusion amount of the abrasive grains is 10 to 50% of the grain size of the abrasive grains. ) To (3) Manufacturing method of the conditioner,
Is to provide.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the CMP conditioner of the present invention, the substrate is formed of a synthetic resin, and the abrasive grains are fixed to the substrate with a synthetic resin that forms the substrate. FIG. 1A is a plan view of an embodiment of the CMP conditioner of the present invention, and FIG. 1B is a perspective view thereof. In the CMP conditioner of this aspect, the abrasive grain layer 2 is provided in the annular portion surrounded by two concentric circles at the peripheral edge of the substrate 1 formed of synthetic resin, and the abrasive layer of the annular portion is Six grooves 3 are provided by being divided into six in a discontinuous manner. By dividing the abrasive conditioner layer of the CMP conditioner in a discontinuous manner and providing grooves, it becomes easier for the polishing liquid to flow in and out of the polishing debris during conditioning of the polishing pad. Can be increased.
The synthetic resin used in the present invention is not particularly limited, and examples thereof include urea resins, melamine resins, phenol resins, epoxy resins, diallyl phthalate resins, polyester resins, polyimide resins and other thermosetting resins, polyimide resins, polyquinoxaline resins, and polyquinolines. Examples thereof include thermoplastic resins such as resins, polycarbonate resins, and polytetrafluoroethylene, and mixed resins of these thermosetting resins and thermoplastic resins. Among these, a phenol resin can be particularly preferably used.
There is no restriction | limiting in particular in the abrasive grain used for this invention, For example, a diamond abrasive grain, a CBN abrasive grain, etc. can be mentioned. Among these, diamond abrasive grains can be suitably used. The grain size of the diamond abrasive grains is preferably # 35 to # 200, and more preferably # 50 to # 120. When the grain size of the diamond abrasive grains becomes coarser than # 35, natural diamond is required and it becomes very expensive. When the grain size of the diamond abrasive grains becomes finer than # 200, it is difficult to ensure a sufficient amount of protrusion of the abrasive grains, and the conditioning time may be increased.
In the present invention, prismatic diamond can also be used as the abrasive. The prismatic diamond to be used has a square cross section with a side length of 0.1 to 1.5 mm, and preferably a length of 1 to 10 mm. As the prismatic diamond, either single crystal diamond or polycrystalline diamond can be used. Examples of the polycrystalline diamond include polycrystalline diamond obtained by cutting a thick film of CVD diamond, and a polycrystalline diamond sintered body. As the prismatic single crystal diamond, a commercially available monodress manufactured by De Beers, Sumicrystal manufactured by Sumitomo Electric Industries, Ltd., or the like can be used. Or what was cut out in the shape of a prism from natural diamond ore can be used. By using prismatic diamond as the abrasive grains, the holding power of the abrasive grains can be improved and the falling off can be reliably prevented, and the performance can be stabilized because there is no change in the cross-sectional area. In addition, when single crystal diamond is used, the lifetime can be stabilized by aligning the crystal orientation.
[0006]
In the CMP conditioner of the present invention, it is preferable that a non-metallic material is contained in the synthetic resin forming the substrate. There are no particular restrictions on the non-metallic material to be included, for example, fiber materials such as glass fiber, ceramic fiber, carbon fiber, aramid fiber, vinylon fiber, powder form such as ceramic powder, calcium carbonate, kaolin, talc, mica, glass powder, etc. Materials etc. can be mentioned. By including a non-metallic material in the synthetic resin, the strength, rigidity, heat resistance, etc. of the substrate can be improved without causing the possibility of contamination of the wafer due to metal elution.
In the manufacturing method of the CMP conditioner of the present invention, abrasive grains are fitted into holes provided on the surface of a mother die, the mother die is filled with synthetic resin, and heated while pressing to form the synthetic resin into the shape of the substrate. In addition, the abrasive grains are fixed to the substrate. FIG. 2 (a) is a plan view of one embodiment of a mother die used in the method of the present invention, and FIG. 2 (b) is a perspective view thereof. In the mother die of this aspect, a hole 5 for fitting abrasive grains is provided at the bottom of the abrasive grain layer cavity 4 divided into six in the annular portion. The depth of the hole is preferably 10 to 50% of the grain size of the abrasive grains, and more preferably 15 to 35%. Since the protrusion amount of the abrasive grains of the CMP conditioner of the present invention is substantially equal to the depth of the hole, the protrusion amount of the abrasive grains of the CMP conditioner can be made uniform by making the hole depth constant. In the method of the present invention, the material of the mother die is not particularly limited, and for example, a graphite die, a die or the like can be used.
[0007]
FIG. 3 is an explanatory view of one embodiment of a method for manufacturing a CMP conditioner according to the present invention. This figure is a partial cross-sectional view taken along a plane parallel to the central axis passing through four holes provided on the surface of the mother die. As shown in FIG. 3A, abrasive grains 7 are fitted into holes 5 provided on the surface of the mother die 6. If necessary, the abrasive can be temporarily bonded to the matrix using an adhesive. It is preferable that the adhesive to be used deteriorates under the molding conditions of the synthetic resin, and after the synthetic resin is molded into the shape of the substrate, the obtained CMP conditioner can be easily removed from the matrix. In the method of the present invention, abrasive grains are fitted into holes provided on the surface of the mother mold, and then the mother mold is filled with synthetic resin. In the embodiment shown in FIG. 3 (b), the space formed by fitting the cylindrical outer mold 8 is filled with the synthetic resin 9 and pressed using the push punch 10. By heating while pressing, the synthetic resin is formed into the shape of the substrate, and the abrasive grains 7 are fixed to the substrate 1 formed of the synthetic resin as shown in FIG. By removing the mother mold, it is possible to obtain a CMP conditioner in which the substrate of the present invention is formed of a synthetic resin and the abrasive grains are fixed to the substrate with the synthetic resin forming the substrate.
[0008]
FIG. 4 is an explanatory diagram of another embodiment of the CMP conditioner manufacturing method of the present invention. In this embodiment, prismatic diamond is used as the abrasive. This figure is a partial cross-sectional view taken along a plane parallel to the central axis passing through four holes provided on the surface of the mother die. As shown in FIG. 4A, a prismatic diamond 11 is fitted into a hole 5 having a circular cross section provided on the surface of the mother die 6. In the method of the present invention, a prismatic diamond is fitted into a hole provided on the surface of the matrix, and then the matrix is filled with a synthetic resin. In the embodiment shown in FIG. 4B, a synthetic resin 9 is filled in a space formed by fitting a cylindrical outer mold 8 and pressed using a push punch 10. By heating while pressing, the synthetic resin is formed into the shape of the substrate, and the prismatic diamond 11 is fixed to the substrate 1 formed of the synthetic resin as shown in FIG. By removing the mother mold, a CMP conditioner can be obtained in which the substrate of the present invention is formed of a synthetic resin, and prismatic diamond abrasive grains are fixed to the substrate by the synthetic resin forming the substrate.
In the method of the present invention, a CMP conditioner in which a nonmetallic material is contained in a synthetic resin can be obtained by adding and mixing a nonmetallic material to the synthetic resin filled in the matrix.
In the CMP conditioner of the present invention, since the substrate is formed of a synthetic resin and does not have a metal portion, there is no possibility of causing contamination of the wafer due to metal elution. Further, since the abrasive grains are fixed to the substrate by a synthetic resin that forms the substrate, unlike the fixing of the abrasive grains using an adhesive, there is no possibility that the abrasive grains fall off. According to the method of the present invention, the CMP conditioner can be manufactured much more easily and the manufacturing cost can be reduced as compared with the conventional method of applying a resin coating to the abrasive grain layer surface.
[0009]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
A CMP conditioner was manufactured using a graphite mold having the shape shown in FIG.
The graphite mold has a diameter of 100 mm and has an annular abrasive grain layer cavity of 10 mm width at the outer peripheral edge, and diamond abrasive grains are fitted into each of the divided abrasive layer cavities. There are 27 holes each.
Diamond abrasive grains having a particle size of # 60 were fitted into the holes, and temporarily bonded using an adhesive [Cemedine Co., Ltd., Industrial Cemedine 110]. The graphite mold was fitted with a cylindrical graphite outer mold having an inner diameter of 100 mm, an outer diameter of 140 mm, and a height of 30 mm, and preheated to 100 ° C. The mother mold was filled with 70 g of a phenol resin, and a pressure of 100 kg / cm ² was applied from above by a punch, and the temperature was raised to 170 ° C. and heated for 10 minutes to cure the phenol resin.
After slow cooling to room temperature, the push punch, outer mold and graphite mold were removed to obtain a CMP conditioner.
Example 2
A CMP conditioner was manufactured using a graphite mold having the shape shown in FIG.
The graphite mold has a diameter of 100 mm, and has an annular abrasive grain layer cavity of 10 mm width at the peripheral edge of the outer periphery, and a prismatic diamond is fitted in each of the divided abrasive grain layer cavities. There are 27 holes each. The hole for fitting the prismatic diamond is a circle having a diameter of 0.6 mm and a depth of 0.2 mm.
A square with a cross-section of 0.4 mm on a side and a prismatic diamond with a length of 2 mm was fitted into the hole. Next, a cylindrical graphite outer mold having an inner diameter of 100 mm, an outer diameter of 140 mm, and a height of 30 mm was fitted into the graphite mold, and preheated to 100 ° C. The mother mold was filled with 70 g of a phenol resin, and a pressure of 100 kg / cm ² was applied from above by a punch, and the temperature was raised to 170 ° C. and heated for 10 minutes to cure the phenol resin.
After slow cooling to room temperature, the push punch, outer mold and graphite mold were removed to obtain a CMP conditioner with a prismatic diamond protrusion of 0.2 mm.
[0010]
【The invention's effect】
In the CMP conditioner of the present invention, the substrate is formed of a synthetic resin and does not have a metal portion. Therefore, when used for conditioning a polishing pad, there is no possibility that the metal will elute and contaminate the wafer. Further, since the abrasive grains are fixed to the substrate by a synthetic resin that forms the substrate, unlike the fixing of the abrasive grains using an adhesive, there is no possibility that the abrasive grains fall off. According to the manufacturing method of the present invention, a CMP conditioner having a substrate formed of a synthetic resin can be easily manufactured by a simple process.
[Brief description of the drawings]
FIG. 1 is a plan view and a perspective view of one embodiment of a CMP conditioner of the present invention.
FIG. 2 is a plan view and a perspective view of one embodiment of a mother die used in the method of the present invention.
FIG. 3 is an explanatory view of one embodiment of a method for producing a CMP conditioner according to the present invention.
FIG. 4 is an explanatory diagram of another embodiment of the CMP conditioner manufacturing method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Abrasive grain layer 3 Groove 4 Abrasive grain layer cavity 5 Hole 6 Master mold 7 Abrasive grain 8 Outer mold 9 Synthetic resin 10 Push punch 11 Square columnar diamond

Claims (4)

A substrate having an abrasive layer made of abrasive grains protruding from the abrasive layer plane on the surface, is pressed heated molded with abrasive grain layer consisting of abrasive grains projecting having no synthetic resin composition part and abrasive made of metal made of synthetic resin is a substrate, the synthetic resin composition abrasive grain layer with consisting of abrasive grains projecting with molded into the shape of the substrate of CMP conditioner by molding press heated, abrasive of the molded synthetic resin substrate abrasives A method of manufacturing a CMP conditioner, characterized by protruding and adhering to the surface of a grain layer. The method for producing a CMP conditioner according to claim 1 , wherein the synthetic resin composition contains a fibrous nonmetallic material or ceramic powder, calcium carbonate, kaolin or mica powdered nonmetallic material. The method for producing a CMP conditioner according to claim 1 or 2, wherein the abrasive grains are diamonds having a square columnar cross section . A substrate having an abrasive layer on the surface is a synthetic resin substrate formed by a synthetic resin composition having no metal portion, and the synthetic resin composition is molded into the shape of the substrate by heating and pressing and abrasive grains Is a method of manufacturing a CMP conditioner that protrudes and adheres to the surface of a molded synthetic resin substrate, in which abrasive grains are fitted into holes of a certain depth provided on the surface of a mother die, and a cylindrical outer mold The synthetic resin composition is filled into the space formed by fitting the mold to the matrix and heated while pressing with a press punch, thereby forming the synthetic resin composition into the shape of the substrate and abrasive grains. The protruding amount of abrasive grains is fixed to 10 to 50% of the grain size of the abrasive grains by fixing the protruding amount to a protruding amount corresponding to the depth of the hole, and fixing. Any of the CMP conditions Manufacturing method of Na.

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