JP2017119314A - Use method of polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a use method of a polishing pad which enables reduction of replacement costs of a polishing pad even when a terminal detection error is caused by slurry leakage during polishing, and to provide a manufacturing method of a semiconductor device.SOLUTION: A polishing pad includes a polishing layer having a polishing area and a light transmission area, and has a light transmission area member having a sub polishing area forming a part of the polishing area and the light transmission area and a polishing area member having a main polishing area forming a part of the polishing area and an opening. A use method of the polishing pad has a polishing pad installation step in which the light transmission area member is installed in the opening of the polishing area member.SELECTED DRAWING: Figure 7

Description

  The present invention is used for flattening optical materials such as lenses and reflecting mirrors, silicon wafers, glass substrates for hard disks, aluminum substrates, and materials that require high surface flatness such as general metal polishing. The present invention relates to a method for using a polishing pad.

  When manufacturing a semiconductor device, a process of forming a conductive film on the wafer surface and forming a wiring layer by photolithography, etching, or the like, a process of forming an interlayer insulating film on the wiring layer, etc. These steps are performed, and irregularities made of a conductor such as metal or an insulator are generated on the wafer surface. In recent years, miniaturization of wiring and multilayer wiring have been advanced for the purpose of increasing the density of semiconductor integrated circuits, and along with this, technology for flattening the irregularities on the wafer surface has become important.

  As a method for flattening the irregularities on the wafer surface, chemical mechanical polishing (hereinafter referred to as CMP) is generally employed. CMP is a technique of polishing using a slurry-like abrasive (hereinafter referred to as slurry) in which abrasive grains are dispersed in a state where the surface to be polished of a wafer is pressed against the polishing surface of a polishing pad. As shown in FIG. 1, for example, a polishing apparatus generally used in CMP includes a polishing surface plate 2 that supports a polishing pad 1 and a support base (polishing head) 5 that supports a material to be polished (semiconductor wafer) 4. And a backing material for uniformly pressing the wafer, and a slurry supply mechanism. The polishing pad 1 is attached to the polishing surface plate 2 by attaching it with a double-sided tape, for example. The polishing surface plate 2 and the support base 5 are disposed so that the polishing pad 1 and the material to be polished 4 supported by each of the polishing surface plate 2 and the support base 5 are opposed to each other, and are provided with rotating shafts 6 and 7 respectively. Further, a pressurizing mechanism for pressing the workpiece 4 against the polishing pad 1 is provided on the support base 5 side.

  When performing such CMP, there is a problem of determining the flatness of the wafer surface. In other words, it is necessary to detect when the desired surface characteristics or planar state is reached. Conventionally, with regard to the thickness of the oxide film, the polishing rate, and the like, a test wafer is periodically processed, and after confirming the result, a product wafer is polished.

  However, in this method, the time and cost for processing the test wafer are wasted, and the polishing result differs between the test wafer and the product wafer that have not been processed in advance due to the loading effect peculiar to CMP. If it is not actually processed, it is difficult to accurately predict the processing result.

  Therefore, recently, in order to solve the above-mentioned problems, there is a demand for a method capable of detecting a point in time when desired surface characteristics and thickness are obtained in the CMP process. Various methods are used for such detection. From the viewpoint of measurement accuracy and spatial resolution in non-contact measurement, an optical detection method in which a film thickness monitoring mechanism using a laser beam is incorporated in a rotating surface plate ( Patent documents 1 to 3) are becoming mainstream. Specifically, the optical detection means detects the end point of polishing by irradiating a wafer with a light beam through a window (light transmission region) through a polishing pad and monitoring an interference signal generated by the reflection. Is the method.

Japanese Patent Laid-Open No. 9-7985 Japanese Patent Laid-Open No. 9-36072 Japanese Patent Application Laid-Open No. 2004-261887

  However, when polishing is repeated with a conventional polishing pad, the slurry may leak from the boundary (seam) between the polishing region and the light transmission region. When the slurry leaks from the boundary between the polishing region and the light transmission region, the slurry adheres to the surface opposite to the polishing surface (light beam irradiation side) of the light transmission region, the light beam is blocked, and the end point is detected. become unable. When an end point detection error occurs, the entire polishing pad is replaced, increasing the polishing cost and the disposal cost of the polishing pad.

  The present invention provides a method for using a polishing pad and a method for manufacturing a semiconductor device that can suppress polishing pad replacement costs and polishing pad disposal costs even if an endpoint detection error due to slurry leakage occurs during polishing. The purpose is to do.

  The present invention includes a polishing layer having a polishing region and a light transmission region, a light transmission region member having a sub-polishing region and the light transmission region which are part of the polishing region, and a part of the polishing region. A method for using a polishing pad having a polishing region member having a main polishing region and an opening, the polishing pad having a polishing pad installation step of installing the light transmission region member in an opening of the polishing region member. How to use.

  The present invention uses a polishing pad including a polishing layer having a polishing region and a light transmission region, and includes a polishing step for polishing the surface of the semiconductor device while detecting the surface of the semiconductor wafer by optical detection means. A manufacturing method, wherein a light transmission region member having a sub-polishing region and a light transmission region which are part of the polishing region, and a polishing region having a main polishing region and an opening which are parts of the polishing region It is a manufacturing method of a semiconductor device which has the polishing pad installation process installed in the opening of the member.

  According to the present invention, even if the slurry adheres to the light transmission region and an end point detection error occurs, only the light transmission region member including the light transmission region can be replaced, and the end point can be replaced without replacing the entire polishing pad. Since the detection error can be eliminated, the replacement cost of the polishing pad and the disposal cost of the polishing pad can be suppressed.

Schematic configuration diagram showing an example of a polishing apparatus used in CMP polishing The schematic block diagram which shows an example of the light transmissive area | region member based on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the cross section of the light transmissive area | region member which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the grinding | polishing area | region member which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the cross section of the grinding | polishing area | region member which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the polishing pad which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the cross section of the polishing pad which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the light transmissive area | region laminated member which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the cross section of the light transmissive area | region laminated member which concerns on the usage method of the polishing pad of this invention. The schematic block diagram which shows an example of the grinding | polishing area | region laminated member which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the cross section of the grinding | polishing area | region laminated member which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the lamination | stacking polishing pad which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the cross section of the lamination | stacking polishing pad which concerns on the usage method of the polishing pad of this invention The schematic block diagram which shows an example of the polishing pad and laminated polishing pad which concern on the usage method of the polishing pad of this invention

<How to use polishing pad>
The method of using the polishing pad of the present embodiment includes a polishing layer having a polishing region and a light transmission region, a light transmission region member having a sub-polishing region and the light transmission region that are part of the polishing region, and A method of using a polishing pad having a polishing region member having a main polishing region and an opening which are a part of the polishing region, wherein the light transmission region member is installed in the opening of the polishing region member. It has an installation process. A method of using the polishing pad of this embodiment will be described with reference to the drawings.

[Polishing pad]
[Light transmission area member]
FIG. 2 is a schematic configuration diagram illustrating the light transmission region member 10, and FIG. 3 is a schematic configuration diagram illustrating a cross section of the light transmission region member 10. As shown in FIGS. 2 and 3, the light transmission region 11 is provided in an opening 13 that penetrates the sub-polishing region 12. As will be described later, by providing the light transmission region member 10 in the through hole 22 of the polishing region member 20, the sub-polishing region 12 becomes a part of the polishing region of the polishing pad 30.

(Light transmission area)
The material for forming the light transmission region 11 is not particularly limited, but a material that enables highly accurate optical end point detection in a state of polishing and has a light transmittance of 5% or more in the entire wavelength range of 400 to 800 nm. It is preferable to use a material having a light transmittance of 10% or more. Examples of such materials include polyurethane resins, polyester resins, phenol resins, urea resins, melamine resins, epoxy resins, and acrylic resins, and other thermosetting resins, polyurethane resins, polyester resins, polyamide resins, cellulose resins, Acrylic resins, polycarbonate resins, halogen resins (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, olefin resins (polyethylene, polypropylene, etc.), thermoplastic resins, butadiene rubber, isoprene rubber, etc. Examples thereof include rubber, photo-curing resin that is cured by light such as ultraviolet rays and electron beams, and photosensitive resin. These resins may be used alone or in combination of two or more.

  The material for forming the light transmission region 11 is preferably the same as the material for forming the sub-polishing region 12 or a material similar to the physical properties of the sub-polishing region 12. In particular, it is preferable to use a polyurethane resin.

  The polyurethane resin comprises an isocyanate component, a polyol component (high molecular weight polyol, low molecular weight polyol, etc.), and a chain extender.

  Examples of the isocyanate component include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate. , P-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate and the like. It is done. These may be used alone or in combination of two or more.

  Examples of the high molecular weight polyol include a polyether polyol typified by polytetramethylene ether glycol, a polyester polyol typified by polybutylene adipate, a polycaprolactone polyol, a reaction product of a polyester glycol such as polycaprolactone and an alkylene carbonate, and the like. The polyester polycarbonate polyol exemplified in the above, obtained by reacting ethylene carbonate with a polyhydric alcohol and then reacting the resulting reaction mixture with an organic dicarboxylic acid, and a transesterification reaction between a polyhydroxyl compound and an aryl carbonate. Examples thereof include polycarbonate polyol. These may be used alone or in combination of two or more.

  In addition to the high molecular weight polyols described above as polyols, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1, Low molecular weight polyols such as 4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, and 1,4-bis (2-hydroxyethoxy) benzene may be used in combination.

  Examples of the chain extender include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, Low molecular weight polyols such as 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, or 2,4-toluenediamine, 2,6-toluenediamine 3,5-diethyl-2,4-toluenediamine, 4,4′-di-sec-butyl-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,3′-dichloro-4,4′-diaminodiphenylmethane 2,2 ′, 3,3′-tetrachloro-4,4′-di Minodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-methylene-bis-methyl Anthranilate, 4,4'-methylene-bis-anthranilic acid, 4,4'-diaminodiphenylsulfone, N, N'-di-sec-butyl-p-phenylenediamine, 4,4'-methylene- Bis (3-chloro-2,6-diethylaniline), 4,4′-methylenebis (o-chloroaniline), 3,3′-dichloro-4,4′-diamino-5,5′-diethyldiphenylmethane, 1 , 2-bis (2-aminophenylthio) ethane, trimethylene glycol di-p-aminobenzoate, 3,5-bis (methylthio)- , It may be mentioned polyamines exemplified in 4-toluenediamine and the like. These may be used alone or in combination of two or more. However, since the polyamines are often colored themselves or resins formed using these are colored in many cases, it is preferable to blend them so as not to impair the physical properties and light transmittance. In addition, when a compound having an aromatic hydrocarbon group is used, the light transmittance on the short wavelength side tends to be lowered. Therefore, it is particularly preferable not to use such a compound. In addition, a compound in which an electron donating group such as a halogen group or a thio group or an electron withdrawing group is bonded to an aromatic ring or the like tends to decrease the light transmittance. Therefore, such a compound may not be used. Particularly preferred. However, you may mix | blend to such an extent that the light transmittance requested | required by the short wavelength side is not impaired.

  The ratio of the isocyanate component, the polyol component, and the chain extender in the polyurethane resin can be appropriately changed depending on the molecular weight of each and the desired physical properties of the light transmission region produced from these. The number of isocyanate groups of the organic isocyanate relative to the total number of functional groups (hydroxyl group + amino group) of the polyol and the chain extender is preferably 0.95 to 1.15, more preferably 0.99 to 1.10. The polyurethane resin can be manufactured by applying a known urethanization technique such as a melting method or a solution method, but it is preferable to manufacture the polyurethane resin by a melting method in consideration of cost, working environment, and the like.

  As the polymerization procedure of the polyurethane resin, either a prepolymer method or a one-shot method is possible. From the viewpoint of stability and transparency of the polyurethane resin during polishing, an isocyanate-terminated prepolymer from an organic isocyanate and a polyol in advance. Is preferably synthesized, and a prepolymer method in which a chain extender is reacted with this is preferred. Moreover, it is preferable that the NCO weight% of the said prepolymer is about 2 to 8 weight%, More preferably, it is about 3 to 7 weight%. If the NCO wt% is less than 2 wt%, the reaction curing tends to take too much time and the productivity tends to decrease. On the other hand, if the NCO wt% exceeds 8 wt%, the reaction rate becomes too fast. As a result, air entrainment or the like occurs, and physical properties such as transparency and light transmittance of the polyurethane resin tend to deteriorate. When there are bubbles in the light transmission region, the attenuation of the reflected light increases due to light scattering, and the polishing end point detection accuracy and the film thickness measurement accuracy tend to decrease. Therefore, in order to remove such bubbles and make the light transmission region non-foamed, it is preferable to sufficiently remove the gas contained in the material by reducing the pressure to 10 Torr or less before mixing the material. . Moreover, in the stirring process after mixing, in the case of the stirring blade type mixer normally used, it is preferable to stir at the rotation speed of 100 rpm or less so that bubbles may not mix. In addition, the stirring step is preferably performed under reduced pressure. Furthermore, since the rotation and revolution type mixer is difficult to mix bubbles even at high rotation, it is also preferable to perform stirring and defoaming using the mixer.

  If necessary, a stabilizer such as an antioxidant, a surfactant, an antistatic agent, abrasive grains, and other additives may be added to the polyurethane resin. In the production of a polyurethane resin, a known catalyst for promoting a polyurethane reaction such as a tertiary amine type or an organic tin type may be used. The type and addition amount of the catalyst are selected in consideration of the flow time for pouring into a mold having a predetermined shape after the stirring step.

  The production method of the light transmission region 11 is not particularly limited, and can be produced by a known method. For example, a polyurethane resin block produced by the above method can be made to have a predetermined thickness using a band saw type or canna type slicer, a method of pouring the resin into a mold having a cavity of a predetermined thickness, a coating technique, A method using a sheet forming technique is used.

  The Asker D hardness of the light transmission region 11 is preferably 30 to 60 degrees, and more preferably 30 to 50 degrees. By using the light transmission region having the hardness, deformation of the light transmission region 11 can be suppressed.

  The size of the light transmission region 11 is not particularly limited, but is preferably the same size as the opening 13. The planar shape of the light transmission region 11 is preferably the same shape as the opening 13. The cross-sectional shape of the light transmission region 11 is preferably the same shape as the opening 13.

  The thickness of the light transmission region 11 is not particularly limited, but is preferably equal to or less than the thickness of the polishing region. When the light transmission region 11 is thicker than the polishing region, the material to be polished may be damaged by the protruding portion during polishing. Further, the light transmission region 11 is deformed by a stress applied during polishing, and is greatly distorted optically. Therefore, there is a possibility that the optical end point detection accuracy of polishing is lowered. On the other hand, if the thickness is too thin, the durability may be insufficient, or a large recess may be formed on the upper surface of the light transmission region 11 to collect a large amount of slurry, which may reduce the optical end point detection accuracy.

(Sub-polishing area)
Examples of the material for forming the sub-polishing region 12 include polyurethane resin, polyester resin, polyamide resin, acrylic resin, polycarbonate resin, halogen-based resin (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, and olefin. Resin (polyethylene, polypropylene, etc.), epoxy resin, and photosensitive resin. These may be used alone or in combination of two or more. The material for forming the sub-polishing region 12 may be the same as or different from that of the light transmission region 11, but it is preferable to use the same material as the material used for the light transmission region 11.

  Polyurethane resin is a particularly preferable material as a material for forming a polishing region because it is excellent in abrasion resistance and a polymer having desired physical properties can be easily obtained by variously changing the raw material composition.

  The isocyanate component that can be used as a raw material for the polyurethane resin that is a material for forming the sub-polishing region 12 is not particularly limited. For example, an isocyanate component that can be used as a raw material for the polyurethane resin that is a material for forming the light transmission region 11. Is mentioned.

  The polyol component that can be used as a raw material for the polyurethane resin that is a material for forming the sub-polishing region 12 is not particularly limited. For example, a high molecular weight that can be used as a raw material for the polyurethane resin that is a material for forming the light transmission region 11. A polyol is mentioned. The number average molecular weight of the high molecular weight polyol that can be used as a raw material for the polyurethane resin that is the material for forming the sub-polishing region 12 is not particularly limited, but is 500 from the viewpoint of the elastic properties of the resulting polyurethane. -2000 is preferred. If the number average molecular weight is less than 500, a polyurethane using the number average molecular weight does not have sufficient elastic properties and becomes a brittle polymer. For this reason, the polishing region produced from this polyurethane becomes too hard, which causes scratches on the wafer surface. Moreover, since it becomes easy to wear, it is not preferable from the viewpoint of the pad life. On the other hand, when the number average molecular weight exceeds 2,000, polyurethane using this is too soft, and the polishing region produced from this polyurethane tends to have poor planarization characteristics.

  Moreover, as the said polyol component, the said low molecular weight polyol can also be used together with the said high molecular weight polyol.

  Examples of the chain extender that can be used as a raw material of the polyurethane resin that is a material for forming the sub-polishing region 12 include 4,4′-methylenebis (o-chloroaniline) (MOCA) and 2,6-dichloro-p-phenylene. Diamine, 4,4′-methylenebis (2,3-dichloroaniline), 3,5-bis (methylthio) -2,4-toluenediamine, 3,5-bis (methylthio) -2,6-toluenediamine, 3 , 5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, trimethylene glycol-di-p-aminobenzoate, polytetramethylene oxide-di-p-aminobenzoate, 1, 2-bis (2-aminophenylthio) ethane, 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphe Lumethane, N, N′-di-sec-butyl-4,4′-diaminodiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, 4,4′-diamino-3,3′-diethyl- 5,5′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diisopropyl-5,5′-dimethyldiphenylmethane, 4,4′-diamino-3,3 ′, 5,5′-tetraethyldiphenylmethane, 4,4′-diamino-3,3 ′, 5,5′-tetraisopropyldiphenylmethane, m-xylylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, m-phenylenediamine, and p -Polyamines exemplified by xylylenediamine or the like, or the above-described low molecular weight polyol components. These may be used alone or in combination of two or more.

  The ratio of the isocyanate component, the polyol component, and the chain extender in the raw material of the polyurethane resin that is the material for forming the sub-polishing region 12 can be variously changed depending on the molecular weight of each, the desired physical properties of the polishing region produced from these. In order to obtain a polishing region having excellent polishing characteristics, the number of isocyanate groups in the isocyanate component relative to the total number of functional groups (hydroxyl group + amino group) of the polyol component and the chain extender is preferably 0.95 to 1.15. Preferably it is 0.99 to 1.10.

  The polyurethane resin as the material for forming the sub-polishing region 12 can be produced by the same method as the above method. In addition, stabilizers such as antioxidants, surfactants, lubricants, pigments, solid beads, fillers such as water-soluble particles and emulsion particles, antistatic agents, abrasive grains, and other materials as necessary. Additives may be added.

  The sub-polishing region 12 is preferably a fine foam. By using a fine foam, the slurry can be held in the fine pores on the surface, and the polishing rate can be increased.

  The method of finely foaming the polyurethane resin, which is a material for forming the sub-polishing region 12, is not particularly limited, and examples thereof include a method of adding hollow beads, a method of foaming by a mechanical foaming method, a chemical foaming method, and the like. . In addition, although each method may be used together, the mechanical foaming method using the silicone type surfactant which is a copolymer of polyalkylsiloxane and polyether is especially preferable. Examples of the silicone surfactant include SH-192, L-5340 (manufactured by Toray Dow Corning Silicon), and the like.

An example of a method for producing a micro-bubble type polyurethane foam will be described below. The manufacturing method of this polyurethane foam has the following processes.
1) Foaming step for producing a cell dispersion of isocyanate-terminated prepolymer A silicone-based surfactant is added to the isocyanate-terminated prepolymer (first component), and the mixture is stirred in the presence of a non-reactive gas to remove the non-reactive gas. Disperse as fine bubbles to obtain a cell dispersion. When the prepolymer is solid at normal temperature, it is preheated to an appropriate temperature and melted before use.
2) Curing Agent (Chain Extender) Mixing Step A chain extender (second component) is added to the above cell dispersion, mixed and stirred to obtain a foaming reaction solution.
3) Casting process The above foaming reaction liquid is poured into a mold.
4) Curing process The foaming reaction liquid poured into the mold is heated and reacted and cured.

  As the non-reactive gas used to form the fine bubbles, non-flammable gases are preferable, and specific examples include nitrogen, oxygen, carbon dioxide, rare gases such as helium and argon, and mixed gases thereof. The use of air that has been dried to remove moisture is most preferable in terms of cost.

  As a stirring device for making non-reactive gas into fine bubbles and dispersing it in an isocyanate-terminated prepolymer containing a silicone-based surfactant, a known stirring device can be used without particular limitation. Specifically, a homogenizer, a dissolver, A two-axis planetary mixer (planetary mixer) is exemplified. The shape of the stirring blade of the stirring device is not particularly limited, but it is preferable to use a whipper-type stirring blade because fine bubbles can be obtained.

  In addition, it is also a preferable aspect to use a different stirring apparatus for the stirring which produces a bubble dispersion liquid in the stirring process, and the stirring which adds and mixes the chain extender in a mixing process. In particular, the stirring in the mixing step may not be stirring that forms bubbles, and it is preferable to use a stirring device that does not involve large bubbles. As such an agitator, a planetary mixer is suitable. There is no problem even if the same stirring device is used as the stirring device for the stirring step and the mixing step, and it is also preferable to adjust the stirring conditions such as adjusting the rotation speed of the stirring blade as necessary. .

  In the production method of polyurethane foam, heating and post-curing the foam that has reacted until the foaming reaction liquid is poured into the mold and no longer flows is effective in improving the physical properties of the foam and is extremely suitable. It is. The foam reaction solution may be poured into the mold and immediately put into a heating oven for post cure, and heat is not immediately transferred to the reaction components under such conditions, so the bubble size does not increase. . The curing reaction is preferably performed at normal pressure because the bubble shape is stable.

  In the production of a polyurethane foam, a known catalyst for promoting a polyurethane reaction such as a tertiary amine type or an organic tin type may be used. The type and addition amount of the catalyst are selected in consideration of the flow time for pouring into a mold having a predetermined shape after the mixing step.

  The polyurethane foam may be produced by a batch method in which each component is metered into a container and stirred, and each component and a non-reactive gas are continuously supplied to the stirring device and stirred to produce bubbles. It may be a continuous production method in which a dispersion is sent out to produce a molded product.

  The average cell diameter of the polyurethane foam is preferably 30 to 80 μm, more preferably 30 to 60 μm. When deviating from this range, the polishing rate tends to decrease, or the planarity (flatness) of the polished object (wafer) after polishing tends to decrease.

  The specific gravity of the polyurethane foam is preferably 0.5 to 1.3. When the specific gravity is less than 0.5, the surface strength of the polishing region decreases, and the planarity of the object to be polished tends to decrease. On the other hand, when the ratio is larger than 1.3, the number of bubbles on the surface of the polishing region decreases, and planarity is good, but the polishing rate tends to decrease.

  The hardness of the polyurethane foam is preferably 45 to 70 degrees as measured by an Asker D hardness meter. When the Asker D hardness is less than 45 degrees, the planarity of the object to be polished is reduced. When the Asker D hardness is more than 70 degrees, the planarity is good but the uniformity of the object to be polished is reduced. There is a tendency.

  The sub-polishing region 12 is manufactured by cutting the polyurethane foam manufactured as described above into a predetermined size.

  The thickness of the sub-polishing region 12 is not particularly limited, but is usually about 0.6 to 4 mm, and preferably 1.0 to 2.5 mm. The sub-polishing region 12 having the thickness may be produced by a method in which the fine foam block is made to have a predetermined thickness using a band saw type or canna type slicer, or a resin having a cavity having a predetermined thickness is used. Examples thereof include a casting and curing method and a method using a coating technique and a sheet forming technique.

  The means for forming the opening 13 is not particularly limited. For example, a method of pressing or grinding with a cutting tool, a method of using a laser such as a carbonic acid laser, or a mold having the shape of the opening 13 is used. And a method of forming the material by pouring it into the material and curing it. In addition, the planar shape, cross-sectional shape, and size of the opening 13 are not particularly limited.

  The light transmission region member 10 can be manufactured by providing an opening 13 in the sub-polishing region 12 and providing the light transmission region 11 in the opening 13. The method for providing the light transmission region 11 in the opening 13 is not particularly limited. For example, (1) the light transmission region 11 is fitted in the opening 13 to form the surface of the sub-polishing region 12 and the light transmission region 11. Examples include a method of bonding the surface with a releasable pressure-sensitive adhesive tape, and (2) a method of pouring a light transmission region forming material into the opening 13 and curing it to form the light transmission region 11.

[Polished over-zone member]
FIG. 4 is a schematic configuration diagram illustrating the polishing region member 20, and FIG. 5 is a schematic configuration diagram illustrating a cross section of the polishing region member 20. As shown in FIGS. 4 and 5, the polishing region member 20 has a main polishing region 21 which is a part of the polishing region, and an opening 22 for providing the light transmission region member 10. The main polishing region 21 becomes a part of the polishing region of the polishing pad 30 by being combined with the light transmission region member 10 as described later.

(Main polishing area)
Examples of the material for forming the main polishing region 21 include polyurethane resin, polyester resin, polyamide resin, acrylic resin, polycarbonate resin, halogen-based resin (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, and olefin. Resin (polyethylene, polypropylene, etc.), epoxy resin, and photosensitive resin. These may be used alone or in combination of two or more. The material for forming the main polishing region 21 may be the same as or different from that of the sub-polishing region 12, but it is preferable to use the same type of material as that used for the sub-polishing region 12.

  The polyurethane resin is particularly preferable as a material for forming the main polishing region 21 because the polyurethane resin is excellent in abrasion resistance and a polymer having desired physical properties can be easily obtained by variously changing the raw material composition.

  The isocyanate component that can be used as a raw material for the polyurethane resin that is a material for forming the main polishing region 21 is not particularly limited. For example, an isocyanate component that can be used as a raw material for the polyurethane resin that is a material for forming the sub-polishing region 12. Is mentioned.

  The polyol component that can be used as a raw material for the polyurethane resin that is a material for forming the main polishing region 21 is not particularly limited. For example, a polyol component that can be used as a raw material for the polyurethane resin that is a material for forming the sub-polishing region 12. Is mentioned.

  The chain extender that can be used as a raw material for the polyurethane resin that is a material for forming the main polishing region 21 is not particularly limited. For example, a chain that can be used as a raw material for the polyurethane resin that is a material for forming the sub-polishing region 12. Examples include extenders.

  The ratio of the isocyanate component, the polyol component, and the chain extender in the polyurethane resin that is the forming material of the main polishing region 21 is, for example, the isocyanate component, the polyol component, and the chain in the polyurethane resin that is the forming material of the sub-polishing region 12. It is the same as the ratio of the extender.

  The polyurethane resin as the material for forming the main polishing region 21 can be manufactured by the same method as described above. In addition, stabilizers such as antioxidants, surfactants, lubricants, pigments, solid beads, fillers such as water-soluble particles and emulsion particles, antistatic agents, abrasive grains, and other materials as necessary. Additives may be added.

  The main polishing region 21 is preferably a fine foam. By using a fine foam, the slurry can be held in the fine pores on the surface, and the polishing rate can be increased. The polyurethane foam can be produced by the same method as described above.

  The average cell diameter, specific gravity, and hardness of the polyurethane foam related to the main polishing region 21 are the same as the average cell size, specific gravity, and hardness of the polyurethane foam related to the sub-polishing region 12.

  The main polishing region 21 is manufactured by cutting the polyurethane foam manufactured as described above into a predetermined size.

  The thickness of the main polishing region 21 is not particularly limited, but is usually about 0.6 to 4 mm, preferably 1.0 to 2.5 mm, but the same thickness as the sub-polishing region 12. More preferably. Examples of the method for producing the main polishing region 21 having the thickness include the same method as the method for producing the sub-polishing region 12.

  The means for forming the opening 22 is not particularly limited, and examples thereof include the same means as the means for forming the opening 13. The planar shape and size of the opening 22 are preferably the same planar shape and size as the light transmission region 10 from the viewpoint of fitting the light transmission region 10 and the suppression of slurry leakage during polishing.

[Polishing pad installation process]
The polishing pad installation step is a step of installing the light transmission region member 10 in the opening 22 of the polishing region member 20. FIG. 6 is a schematic configuration diagram showing a polishing pad 30 in which the light transmission region member 10 is installed in the opening 22 of the polishing region member 20, and FIG. 7 shows the light transmission region member 10 in the polishing. 3 is a schematic configuration diagram showing a cross section of a polishing pad 30 installed in an opening 22 of a region member 20. FIG. As shown in FIGS. 6 and 7, the polishing pad 30 has the light transmission region member 10 in the opening 22 of the polishing region member 20. The polishing pad 30 has a sub polishing region 12 of the light transmission region member 10 and a main polishing region 21 of the polishing region member 20 as polishing regions.

  A method of installing the light transmission region member 10 in the opening 22 of the polishing region member 20 is not particularly limited. For example, (i) after the light transmission region member 10 is installed on a polishing surface plate, the polishing is performed. The polishing region member 20 may be disposed on the polishing surface plate so that the light transmission region member 10 disposed on the surface plate is provided in the opening 22, or (ii) the polishing region member 20 is ground and fixed. After being installed on the board, the light transmission region member 10 may be installed in the opening 22 of the polishing region member 20 installed on the polishing surface plate. In the case of the aspect (i), the polishing pad installation step includes a light transmission region member installation step of installing the light transmission region member 10 on a polishing surface plate, and a light transmission region member 10 installed on the polishing surface plate. Has a polishing area setting step of setting the polishing area member 20 on a polishing surface plate so that the opening area 22 is provided in the opening 22. In the case of (ii), the polishing pad installation step includes a polishing region installation step of installing the polishing region member 20 on a polishing surface plate, and an opening 22 of the polishing region member 20 installed on the polishing surface plate. A light transmission region member installation step of installing the light transmission region member 10 therein.

  The method of fixing the light transmission region member 10 and the polishing region member 20 to the polishing surface plate is not particularly limited, and examples thereof include a method of fixing with a double-sided tape.

  The sub-polishing region 12 of the light transmission region member 10 and the main polishing region 21 of the polishing region member 20 may be made of different materials, but from the viewpoint of polishing stability and the cut rate during polishing. From the viewpoint of manageability of the relationship between the life of the polishing pad and the polishing pad, it is preferable that they are made of the same material.

[Polishing process]
The polishing step is a step of polishing the surface of the object to be polished with the polishing pad 30 while detecting the surface of the object to be polished with optical detection means. The polishing step includes a light transmission region member replacement step in which only the light transmission region member 10 is replaced when an optical detection error caused by the light transmission region member 10 occurs.

<Semiconductor device manufacturing method>
The semiconductor device is manufactured through a step of polishing the surface of the semiconductor wafer using the polishing pad 30. A semiconductor wafer is generally a laminate of a wiring metal and an oxide film on a silicon wafer. The method and apparatus for polishing the semiconductor wafer are not particularly limited. For example, as shown in FIG. 1, a polishing surface plate 2 that supports a polishing pad (polishing layer) 1 and a support table (polishing head) that supports the semiconductor wafer 4. 5 and a polishing apparatus equipped with a backing material for uniformly pressing the wafer and a supply mechanism of the abrasive 3. The polishing pad 1 is attached to the polishing surface plate 2 by attaching it with a double-sided tape, for example. The polishing surface plate 2 and the support base 5 are disposed so that the polishing pad 1 and the semiconductor wafer 4 supported on each of the polishing surface plate 2 and the support table 5 face each other, and are provided with rotating shafts 6 and 7 respectively. Further, a pressurizing mechanism for pressing the semiconductor wafer 4 against the polishing pad 1 is provided on the support base 5 side. In polishing, the semiconductor wafer 4 is pressed against the polishing pad 1 while rotating the polishing surface plate 2 and the support base 5, and polishing is performed while supplying slurry. The flow rate of the slurry, the polishing load, the polishing platen rotation speed, and the wafer rotation speed are not particularly limited and are appropriately adjusted.

  As a result, the protruding portion of the surface of the semiconductor wafer 4 is removed and polished flat. Thereafter, a semiconductor device is manufactured by dicing, bonding, packaging, or the like. The semiconductor device is used for an arithmetic processing device, a memory, and the like.

  The method for manufacturing a semiconductor device according to the present embodiment uses a polishing pad 30 including a polishing layer having a polishing region and a light transmission region 11, and detects the surface of the semiconductor wafer while detecting the surface of the semiconductor wafer with optical detection means. A method of manufacturing a semiconductor wafer including a polishing step of polishing, wherein a light transmissive region member 10 having a sub-polishing region 12 and a light transmissive region 11 which are part of the polishing region is formed in a part of the polishing region. A polishing pad installation step is provided in which the polishing region member 20 having a certain main polishing region 21 and the opening 22 is installed in the opening 22.

  Since the polishing pad installation process according to the semiconductor device manufacturing method is the same as the polishing pad installation process according to the method of using the polishing pad, the description thereof is omitted.

<Other embodiments>
[Method of Using Laminated Polishing Pad and Manufacturing Method of Semiconductor Device Using the Laminated Polishing Pad]
The polishing pad may be a laminated polishing pad having a support layer. The laminated polishing pad includes a light transmission region laminated member and a polishing region laminated member. The light transmission region laminated member includes a light transmission region member having a sub-polishing region and a light transmission region which are part of a polishing region, and a sub-support layer which is a part of the support layer and has a through hole. The light transmission region and the through hole are laminated via an adhesive member a so as to overlap. In the polishing region laminated member, a polishing region member having a main polishing region that is a part of the polishing region and a main support layer that is a part of the support layer are stacked via an adhesive member b, The main polishing region member, the adhesive member b, and a through-hole penetrating the main support layer are included. The laminated polishing pad will be described with reference to the drawings.

[Light transmission region laminated member]
FIG. 8 is a schematic configuration diagram showing the light transmission region laminate member 40, and FIG. 9 is a schematic configuration diagram showing a cross section of the light transmission region laminate member 40. The light transmission region laminated member 40 includes a light transmission region member 44 having a sub-polishing region 42 and a light transmission region 41 which are part of the polishing region, and a part of the support layer and has a through hole 45. A sub-support layer 46 is laminated via an adhesive member a47 so that the light transmission region 41 and the through hole 45 overlap each other. As will be described later, by providing the light transmission region laminated member 40 in the through hole 55 of the polishing region laminated member 50, the sub-polishing region 42 becomes a part of the polishing region of the laminated polishing pad 60.

(Light transmission area and sub-polishing area)
The light transmission region 41 and the sub-polishing region 42 are the same as the light transmission region 11 and the sub-polishing region 12, respectively, and thus description thereof is omitted.

(Sub support layer)
The front sub-support layer 46 supplements the characteristics of the sub-polishing region 42. As the sub support layer 46, a layer (cushion layer) having a lower elastic modulus than the sub polishing region 42 may be used, or a layer (high elastic layer) having a higher elastic modulus than the sub polishing region 42 may be used. The cushion layer is necessary in order to achieve both planarity and uniformity in a trade-off relationship in CMP. Planarity refers to the flatness of a pattern portion when a material having fine irregularities generated during pattern formation is polished, and uniformity refers to the uniformity of the entire material to be polished. The planarity is improved by the characteristics of the sub-polishing region 42, and the uniformity is improved by the characteristics of the cushion layer. The high elastic layer is used for improving the planarization characteristics of the polishing pad when a soft polishing layer is used in CMP to suppress the occurrence of scratches. In addition, by using a highly elastic layer, it is possible to suppress excessive cutting of the edge portion of the material to be polished.

  Examples of the cushion layer include fiber nonwoven fabrics such as polyester nonwoven fabric, nylon nonwoven fabric, and acrylic nonwoven fabric; resin-impregnated nonwoven fabrics such as polyester nonwoven fabric impregnated with polyurethane; polymer resin foams such as polyurethane foam and polyethylene foam; butadiene rubber And rubber resins such as isoprene rubber; and photosensitive resins.

  The thickness of the cushion layer is not particularly limited, but is preferably 300 to 1800 μm, more preferably 700 to 1400 μm.

  Examples of the highly elastic layer include a metal sheet and a resin film. Examples of the resin film include polyester films such as polyethylene terephthalate film and polyethylene naphthalate film; polyolefin films such as polyethylene film and polypropylene film; nylon film; polyimide film and the like.

  The thickness of the highly elastic layer is not particularly limited, but is preferably 10 to 200 μm, more preferably 15 to 55 μm from the viewpoints of rigidity, dimensional stability during heating, and the like.

  The means for forming the through hole 45 is not particularly limited. For example, the same means that can be applied as the means for forming the opening 13 can be used. The planar shape, cross-sectional shape, and size of the through hole 45 are not particularly limited.

(Adhesive member a)
The adhesive member a47 is not particularly limited, and examples thereof include double-sided tapes, rubber adhesives, acrylic adhesives, hot melt adhesives, and the like. A pressure-sensitive double-sided tape having a layer is preferred. The base material of the pressure-sensitive double-sided tape can prevent the slurry from penetrating into the support layer, and can prevent peeling between the support layer and the adhesive layer.

  The double-sided tape has a general configuration in which adhesive layers are provided on both sides of a substrate such as a nonwoven fabric or a film. The base material can prevent the slurry from penetrating to the support layer side, and can prevent peeling between the support layer and the adhesive layer.

  Examples of the base material include resin films, and examples of the resin film include polyester films such as polyethylene terephthalate film and polyethylene naphthalate film; polyolefin films such as polyethylene film and polypropylene film; nylon films; polyimide films and the like. It is done. Among these, it is preferable to use a polyester film having excellent properties for preventing water permeation.

  The thickness of the substrate is not particularly limited, but is preferably 10 to 200 μm, more preferably 15 to 55 μm from the viewpoints of transparency, flexibility, rigidity, dimensional stability during heating, and the like.

  When using the said double-sided tape, it is preferable that the thickness of the said adhesive bond layer is 10-200 micrometers, More preferably, it is 30-100 micrometers.

  Examples of the composition of the adhesive layer include rubber adhesives and acrylic adhesives. In addition, since the composition of the polishing region and the cushion layer may be different, the composition of each adhesive layer of the double-sided tape can be made different so that the adhesive force of each layer can be optimized.

  The light transmission region laminated member 40 is manufactured by bonding the light transmission region member 44 and the sub support layer 46 with the adhesive member a47 so that the light transmission region 41 and the through hole 45 overlap each other. be able to.

(Polished area laminated member)
FIG. 10 is a schematic configuration diagram showing the polishing region laminated member 50, and FIG. 11 is a schematic configuration diagram showing a cross section of the polishing region laminated member 50. The polishing region laminated member 50 includes a polishing region member 54 having a main polishing region 51 which is a part of the polishing region, and a main support layer 56 which is a part of the support layer, laminated via an adhesive member b57. And a through hole 55 penetrating the polishing region member 54, the adhesive member b57, and the main support layer 56. As will be described later, the main polishing region 51 becomes a part of the polishing region of the polishing pad 60 by combining the light transmission region stacking member 40 and the polishing region stacking member 50.

(Main polishing area and main support layer)
The main polishing region 51 and the main support layer 56 are the same as the main polishing region 21 and the sub support layer 46, respectively, and thus description thereof is omitted.

(Adhesive member b)
The adhesive member b57 is not particularly limited, and examples thereof include an adhesive such as a double-sided tape, a rubber adhesive, an acrylic adhesive, and a hot melt adhesive. From the viewpoint of suppressing peeling of the cushion layer and the polishing layer, An adhesive member having no material is preferable, and a hot melt adhesive is more preferable.

  As the hot-melt adhesive member, a general hot-melt adhesive can be used, but a polyester-based hot-melt adhesive is preferable from the viewpoint of suppressing peeling of the cushion layer and the polishing layer. As the polyester hot melt adhesive, for example, those described in JP-A-2014-24123 can be used.

  The melting point of the hot melt adhesive is preferably 100 to 200 ° C. When the melting point is less than 100 ° C., the adhesive force of the hot melt adhesive is reduced due to heat generated during polishing, and when it exceeds 200 ° C., the temperature at which the hot melt adhesive is melted increases, The pad is warped and tends to adversely affect the polishing characteristics.

  The thickness of the adhesive member b57 is preferably 10 to 200 μm, more preferably 30 to 100 μm, from the viewpoint of suppressing peeling of the cushion layer and the polishing layer.

  The method for producing the polishing region laminated member 50 is not particularly limited. For example, (1) the polishing region member 54 and the main support layer 56 are provided with through holes, respectively, and the polishing region member 54 and the main support layer are provided. 56 is bonded by the adhesive member b57 so that the through-holes overlap, and (2) after the polishing region member 51 and the main support layer 56 are bonded by the adhesive member b57. And a method of forming the through hole 55. The means for forming the through hole is not particularly limited, and examples thereof include a method of forming the through hole 25 with a cutting tool or a laser. The planar shape and size of the through hole 55 are preferably the same planar shape and size as the light transmission region member 40 from the viewpoint of suppressing slurry leakage during polishing.

[Laminated polishing pad installation process]
The laminated polishing pad installation step is a step of installing the light transmission region member 40 in the opening 55 of the polishing region member 50. FIG. 12 is a schematic configuration diagram showing the laminated polishing pad 60, and FIG. 13 is a schematic configuration diagram showing a cross section of the laminated polishing pad 60. As shown in FIGS. 12 and 13, the laminated polishing pad 60 has the light transmission region laminated member 40 in the through hole 55 of the polishing region laminated member 50. The polishing pad 60 has a sub-polishing region 42 of the light-transmitting region laminate member 40 and a main polishing region 51 of the polishing region laminate member 50 as polishing regions, and the sub-support layer 46 of the light-transmitting region laminate member 40; The main support layer 56 of the polishing region laminated member 50 is provided as a support layer.

  The adhesive member a47 is a pressure-sensitive double-sided tape having adhesive layers on both sides of the base material from the viewpoint of suppressing slurry leakage and from suppressing the peeling of the main polishing region and the main support layer, and the material of the adhesive member b57 is hot. A melt adhesive is preferred.

  The means for providing the light transmission region laminate member 40 in the through hole 55 is not particularly limited. For example, the light transmission region laminate member 40 is fitted into the through hole 55 so that the surface of the light transmission region laminate member 40 and the polishing region laminate member are disposed. And a method of pasting 50 surfaces with a releasable adhesive tape.

  The laminated polishing pad 60 may be provided with a double-sided tape on the surface to be bonded to the platen. As the double-sided tape, a tape having a general configuration in which an adhesive layer is provided on both surfaces of a base material can be used as described above.

  In the above description, the method for using the polishing pad in which the outer periphery of the through hole related to the polishing region member and the polishing region laminated member is closed and the method for manufacturing the semiconductor device have been described. However, in another embodiment, as shown in FIG. 14, the polishing pad 30 may have a shape in which the outer peripheral side of the through hole 22 related to the polishing region member 20 is opened.

  The method of using the polishing pad and the method of manufacturing a semiconductor device according to the present invention include optical materials such as lenses and reflection mirrors, silicon wafers, glass substrates for hard disks, aluminum substrates, and high surface flatness such as general metal polishing. It can be used for planarization processing of materials that require properties.

1, 30, 60: Polishing pad 2: Polishing surface plate 3: Abrasive (slurry)
4: Material to be polished (semiconductor wafer)
5: Support base (polishing head)
6, 7: Rotating shafts 10, 44: Light transmission region member 11, 41: Light transmission region 12, 42: Sub polishing region 13, 43: Opening 20, 20, 54: Polishing region member 21, 51: Main polishing region 22, 45, 55: Through hole 40: Light transmission region laminated member 46: Sub support layer 47: Adhesive member a
50: Polishing region laminated member 56: Main support layer 57: Adhesive member b

Claims (8)

A light transmission region member including a polishing layer having a polishing region and a light transmission region, and having a sub-polishing region and the light transmission region which are part of the polishing region, and a main polishing region which is a part of the polishing region And a method of using a polishing pad having a polishing region member having an opening,
A method of using a polishing pad comprising a polishing pad installation step of installing the light transmission region member in an opening of the polishing region member. The polishing pad installation step is a light transmission region member installation step of installing the light transmission region member on a polishing surface plate,
2. The use of the polishing pad according to claim 1, further comprising: a polishing region installation step of installing the polishing region member on the polishing surface plate so that the light transmission region member installed on the polishing surface plate is provided in the opening. Method.   The polishing pad installation step includes a polishing region installation step of installing the polishing region member on a polishing surface plate, and a light transmission region of installing the light transmission region member in an opening of the polishing region member installed on the polishing surface plate. The method for using the polishing pad according to claim 1, further comprising a member installation step. A polishing step of polishing the surface of the object to be polished with the polishing pad while detecting the surface of the object to be polished with an optical detection means;
The said grinding | polishing process WHEREIN: When the optical detection error resulting from the said light transmissive area | region member generate | occur | produces, it has the light transmissive area | region member replacement | exchange process of replacing | exchanging only the said light transmissive area | region member. How to use a polishing pad. A method for manufacturing a semiconductor wafer, comprising a polishing step of polishing a surface of a semiconductor wafer while detecting the surface of the semiconductor wafer by optical detection means using a polishing pad including a polishing layer having a polishing region and a light transmission region. And
A light transmission region member having a sub-polishing region that is a part of the polishing region and a light transmission region is disposed in the opening of a polishing region member that has a main polishing region and an opening that are a part of the polishing region. A method for manufacturing a semiconductor device, comprising a step of installing a polishing pad. The polishing pad installation step is a light transmission region member installation step of installing the light transmission region member on a polishing surface plate,
6. A semiconductor device manufacturing method according to claim 5, further comprising: a polishing region installation step of installing the polishing region member on the polishing surface plate so that the light transmission region member installed on the polishing surface plate is provided in the opening. Method.   The polishing pad installation step includes a polishing region installation step of installing the polishing region member on a polishing surface plate, and a light transmission region of installing the light transmission region member in an opening of the polishing region member installed on the polishing surface plate. The method for manufacturing a semiconductor device according to claim 5, further comprising a member installation step.   8. The light transmission region member replacement step of replacing only the light transmission region member when an optical detection error caused by the light transmission region member occurs during polishing of the semiconductor wafer. Semiconductor device manufacturing method.

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