JP2006110686A - Polishing pad - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing pad, detecting the optical end point with high accuracy in the process of polishing, and preventing slurry from leaking between a polishing area and a light transmission area even in the case of long-time use, and to provide a manufacturing method of a semiconductor device using the polishing pad. <P>SOLUTION: In the polishing pad having the polishing area and the light transmission area, the polishing area has an opening area for providing the light transmission area, a rugged part A is formed in the periphery of the opening part, a rugged part B is formed in the periphery of the light transmission area, and the rugged part A and the rugged part B are engaged with each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

    The present invention relates to a polishing pad for use in planarizing unevenness on a surface of an object to be polished such as a semiconductor wafer by chemical mechanical polishing (CMP), and more specifically, a window for detecting a polishing state or the like by optical means. And a method of manufacturing a semiconductor device using the polishing pad.

  When manufacturing a semiconductor device, a conductive film is formed on the surface of a semiconductor wafer (hereinafter also referred to as a wafer), and a wiring layer is formed by photolithography, etching, or the like. A process for forming an interlayer insulating film is performed on the surface of the wafer, and these processes cause irregularities made of a conductor such as metal or an insulator 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, a CMP method 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.

  A polishing apparatus generally used in CMP includes, for example, a polishing surface plate for supporting a polishing pad, a support table (polishing head) for supporting an object to be polished (such as a wafer), and a backing for uniformly pressing the wafer. A material and an abrasive supply mechanism are provided. For example, the polishing pad is attached to the polishing surface plate by pasting with a double-sided tape. The polishing surface plate and the support base are arranged so that the polishing pad supported by the polishing table and the object to be polished face each other, and each has a rotation shaft. Further, the support base is provided with a pressurizing mechanism for pressing the object to be polished against the polishing pad.

  In performing such CMP, there is a problem in determining the wafer surface flatness. 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. Currently proposed detection means include
(1) Torque detection method for detecting a friction coefficient between a wafer and a pad as a change in rotational torque of a wafer holding head or a surface plate (Patent Document 1)
(2) Capacitance method for detecting the thickness of the insulating film remaining on the wafer (Patent Document 2)
(3) An optical method in which a film thickness monitoring mechanism using laser light is incorporated in a rotating surface plate (Patent Document 3, Patent Document 4)
(4) Vibration analysis method for analyzing frequency spectrum obtained from vibration or acceleration sensor attached to head or spindle (5) Differential transformer application detection method built in head (6) Friction heat and slurry between wafer and polishing pad Method of measuring reaction heat between target and object to be polished with infrared radiation thermometer (Patent Document 5)
(7) Method of measuring the thickness of an object to be polished by measuring the propagation time of ultrasonic waves (Patent Document 6, Patent Document 7)
(8) Method for measuring sheet resistance of metal film on wafer surface (Patent Document 8)
Etc. Currently, the method (1) is widely used, but the method (3) is becoming mainstream from the viewpoint of measurement accuracy and spatial resolution in non-contact measurement.

  The optical detection means which is the method of (3) is specifically by irradiating a wafer through a window (light transmission region) through a polishing pad and monitoring an interference signal generated by the reflection. This is a method for detecting the end point of polishing.

  Currently, white light using a He—Ne laser light having a wavelength near 600 nm or a halogen lamp having a wavelength light in the range of 380 to 800 nm is generally used as the light beam.

  In such a method, the end point is determined by monitoring the change in the thickness of the surface layer of the wafer and knowing the approximate depth of the surface irregularities. When such a change in thickness becomes equal to the depth of the unevenness, the CMP process is terminated. Various methods have been proposed for the polishing end point detection method using such optical means and the polishing pad used in the method.

  For example, a polishing pad having at least a part of a transparent polymer sheet that transmits solid and homogeneous light having a wavelength of 190 nm to 3500 nm is disclosed (Patent Document 9). Further, a polishing pad in which a stepped transparent plug is inserted is disclosed (Patent Document 3). Furthermore, a polishing pad having a transparent plug that is flush with the polishing surface is disclosed (Patent Document 10).

  Furthermore, proposals (Patent Documents 11 and 12) have been made to prevent the slurry from leaking from the boundary (seam) between the polishing region and the light transmission region. However, even when these transparent leakage prevention sheets are provided, the slurry leaks from the boundary (seam) between the polishing region and the light transmission region to the lower part of the polishing layer, and the slurry accumulates on the leakage prevention sheet to cause an optical end point. Problems with detection.

In the future, with high integration and ultra-miniaturization in semiconductor manufacturing, it is expected that the wiring width of integrated circuits will become smaller, and in that case, highly accurate optical end point detection will be required. The end point detection window cannot sufficiently solve the problem of slurry leakage.
US Pat. No. 5,069,002 US Pat. No. 5,081,421 Japanese Patent Laid-Open No. 9-7985 Japanese Patent Laid-Open No. 9-36072 US Pat. No. 5,196,353 JP-A-55-106769 JP 7-135190 A US Pat. No. 5,559,428 Japanese National Patent Publication No. 11-512977 Japanese Patent Laid-Open No. 10-83977 JP 2001-291686 A Japanese translation of PCT publication No. 2003-510826

  The present invention has been made in order to solve the above problems, and enables high-precision optical end point detection in a state where polishing is performed, and even when used for a long period of time, a polishing region and a light transmission region. It is an object of the present invention to provide a polishing pad that can prevent slurry leakage from between and a method for manufacturing a semiconductor device using the polishing pad.

  As a result of intensive studies in view of the present situation as described above, the present inventor uses a polishing pad having the following structure, so that even when used for a long period of time, a gap between the polishing region and the light transmission region can be obtained. It has been found that slurry leakage can be prevented.

  That is, according to the present invention, in a polishing pad having a polishing region and a light transmission region, the polishing region has an opening for providing the light transmission region, and an uneven portion A is formed around the opening. Further, the present invention relates to a polishing pad in which an uneven portion B is formed around the light transmission region, and the uneven portion A and the uneven portion B are engaged.

  A conventional polishing pad having a polishing region and a light transmission region has a structure that does not have an uneven portion around the opening and the light transmission region, as shown in FIGS. In CMP, a polishing pad and an object to be polished such as a wafer rotate and revolve together, and polishing is performed by friction under pressure. During polishing, various forces (particularly in the horizontal direction) are acting on the light transmission region and the polishing region, so that a peeling state always occurs at the boundary between both members. It is considered that the conventional polishing pad is easily peeled off at the boundary between the two members, and a gap is generated at the boundary to cause slurry leakage. This slurry leakage is considered to cause optical problems such as fogging in the light end point detection unit, thereby reducing or disabling the end point detection accuracy.

  Since the polishing pad of the present invention has a characteristic structure as described above, even if a force that peels off the light transmission region and the polishing region is applied during polishing, the polishing pad has sufficient resistance to withstand it. Therefore, peeling hardly occurs at the boundary between the light transmission region and the polishing region, and slurry leakage can be effectively prevented. Further, during polishing, the object to be polished is pressed against the polishing pad by the pressurizing mechanism, and the engaging portion between the concavo-convex portion A and the concavo-convex portion B is brought into close contact by the vertical force acting on the polishing pad, so that it is more effective. Slurry leakage can be prevented.

  In the polishing pad, an adhesive layer made of an adhesive containing a thermosetting resin or a photocurable resin is preferably provided between the uneven portion A and the uneven portion B. It is preferable that the engagement portion between the concavo-convex portion A and the concavo-convex portion B is as close as possible, but, for example, when manufacturing by fitting the light transmission region having the concavo-convex portion B into the opening having the concavo-convex portion A, Since it is difficult to form a concavo-convex shape that perfectly matches, a gap may occur in the engaging portion. Therefore, by providing an adhesive layer made of an adhesive containing a thermosetting resin or a photocurable resin between the concavo-convex portion A and the concavo-convex portion B, the gap between the engaging portions can be completely filled. In addition, the adhesion between the concavo-convex portion A and the concavo-convex portion B can be increased, and the engagement (fitting) can be further strengthened. Therefore, slurry leakage can be prevented more effectively. Thermosetting resins and photocurable resins are preferable materials for forming the adhesive layer because they can be easily cured by heating or light irradiation.

  Another polishing pad of the present invention is a polishing pad having a polishing region and a light transmission region, wherein the polishing region has an opening for providing the light transmission region, and is provided around the opening and inside the polishing region. A concave portion C is formed, a convex portion D is formed around the light transmission region, and the concave portion C and the convex portion D are engaged with each other.

  Even the structure of the polishing pad can effectively prevent slurry leakage. The reason is that the object to be polished is pressed against the polishing pad by the pressurizing mechanism during polishing, and the engagement portion between the concave portion C and the convex portion D is more closely adhered by the vertical force acting on the polishing pad. it is conceivable that.

  In the present invention, the material for forming the light transmission region is preferably a non-foamed material. If it is a non-foamed material, light scattering can be suppressed, so that an accurate reflectance can be detected and the detection accuracy of the polishing optical end point can be increased.

  Further, it is preferable that the polishing surface of the light transmission region does not have a concavo-convex structure that holds and renews the polishing liquid. If there is macroscopic surface irregularities on the polishing side surface of the light transmission region, slurry containing additives such as abrasive grains accumulates in the recesses, and light scattering / absorption tends to affect detection accuracy. Further, it is preferable that the other surface side surface of the light transmission region does not have macro surface unevenness. This is because if there are macro surface irregularities, light scattering is likely to occur, which may affect detection accuracy.

  In the present invention, the forming material of the polishing region is preferably a fine foam.

  Moreover, it is preferable that the groove | channel is provided in the grinding | polishing side surface of the said grinding | polishing area | region.

  The average cell diameter of the fine foam is preferably 70 μm or less, more preferably 50 μm or less. If the average bubble diameter is 70 μm or less, planarity (flatness) is good.

  Moreover, it is preferable that the specific gravity of the said fine foam is 0.5-1.0, More preferably, it is 0.7-0.9. When the specific gravity is less than 0.5, the strength of the surface of the polishing region decreases, and the planarity of the object to be polished decreases. When the specific gravity is greater than 1.0, the number of fine bubbles on the surface of the polishing region decreases. The planarity is good, but the polishing rate tends to be small.

  Further, the hardness of the fine foam is preferably 35 to 65 degrees in terms of Asker D hardness, more preferably 35 to 60 degrees. When the Asker D hardness is less than 35 degrees, the planarity of the object to be polished is reduced. When the Asker D hardness is more than 65 degrees, the planarity is good, but the uniformity of the object to be polished is decreased. Tend to.

  Moreover, it is preferable that the compression rate of the said fine foam is 0.5 to 5.0%, More preferably, it is 0.5 to 3.0%. If the compression ratio is within the above range, both planarity and uniformity can be sufficiently achieved. The compression rate is a value calculated by the following formula.

Compression rate (%) = {(T1-T2) / T1} × 100
T1: Thickness of the fine foam when a stress load of 30 kPa (300 g / cm ² ) is maintained for 60 seconds from an unloaded state on the fine foam.
T2: The thickness of the fine foam when a stress load of 180 kPa (1800 g / cm ² ) is maintained for 60 seconds from the state of T1.

  Moreover, it is preferable that the compression recovery rate of the said fine foam is 50 to 100%, More preferably, it is 60 to 100%. When it is less than 50%, as the repeated load is applied to the polishing region during polishing, a large change appears in the thickness of the polishing region, and the stability of the polishing characteristics tends to decrease. The compression recovery rate is a value calculated by the following formula.

Compression recovery rate (%) = {(T3-T2) / (T1-T2)} × 100
T1: Thickness of the fine foam when a stress load of 30 kPa (300 g / cm ² ) is maintained for 60 seconds from an unloaded state on the fine foam.
T2: The thickness of the fine foam when a stress load of 180 kPa (1800 g / cm ² ) is maintained for 60 seconds from the state of T1.
T3: The thickness of the fine foam when held for 60 seconds in a no-load state from the state of T2, and then holding a stress load of 30 kPa (300 g / cm ² ) for 60 seconds.

  Moreover, it is preferable that the storage elastic modulus in 40 degreeC and 1 Hz of the said fine foam is 150 Mpa or more, More preferably, it is 250 Mpa or more. When the storage elastic modulus is less than 150 MPa, the strength of the surface of the polishing region decreases, and the planarity of the object to be polished tends to decrease. The storage elastic modulus is an elastic modulus measured by applying a sinusoidal vibration to a fine foam using a dynamic viscoelasticity measuring device and using a tensile test jig.

  The present invention also relates to a method for manufacturing a semiconductor device including a step of polishing a surface of a semiconductor wafer using the polishing pad described above.

  The polishing pad of the present invention has at least a polishing region and a light transmission region.

  The material for forming the light transmission region is not particularly limited, but it is possible to detect the optical end point with high accuracy while polishing and use a material having a light transmittance of 20% or more over the entire wavelength range of 400 to 700 nm. It is preferable that the material has a light transmittance of 50% 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, Thermoplastic resins such as acrylic resins, polycarbonate resins, halogen resins (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, and olefin resins (polyethylene, polypropylene, etc.), light such as ultraviolet rays and electron beams And a photo-curable resin that is cured by the above-described method and a photosensitive resin. These resins may be used alone or in combination of two or more. The thermosetting resin is preferably one that cures at a relatively low temperature. When using a photocurable resin, it is preferable to use a photopolymerization initiator in combination.

  In addition, it is preferable to use a material similar to the material used for the polishing region and the physical properties of the polishing region. In particular, a highly abrasion-resistant polyurethane resin that can suppress light scattering in the light transmission region due to dressing marks during polishing is desirable.

  The polyurethane resin is composed of organic isocyanate, polyol (high molecular weight polyol or low molecular weight polyol), and chain extender.

  Examples of the organic isocyanate 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, Examples include 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. . These may be used alone or in combination of two or more.

  As the organic isocyanate, in addition to the diisocyanate compound, a trifunctional or higher polyfunctional polyisocyanate compound can also be used. As a polyfunctional isocyanate compound, a series of diisocyanate adduct compounds are commercially available as Desmodur-N (manufactured by Bayer) or trade name Duranate (manufactured by Asahi Kasei Kogyo Co., Ltd.). These trifunctional or higher functional polyisocyanate compounds are preferably used by adding to the diisocyanate compound because they are easily gelled during prepolymer synthesis when used alone.

  Examples of the high molecular weight polyol include polyether polyols typified by polytetramethylene ether glycol, polyester polyols typified by polybutylene adipate, polycaprolactone polyol, and a reaction product of a polyester glycol such as polycaprolactone and alkylene carbonate. Polyester polycarbonate polyol, polyester polycarbonate polyol obtained by reacting ethylene carbonate with polyhydric alcohol and then reacting the resulting reaction mixture with organic dicarboxylic acid, and polycarbonate polyol obtained by transesterification reaction between polyhydroxyl compound and aryl carbonate Etc. 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.

  Chain extenders include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3 -Low molecular weight polyols such as 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′-diamino Phenylmethane, 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), 3,3′-dichloro-4,4′-diamino-5,5′-diethyldiphenylmethane, 1,2-bis (2-aminophenylthio) ethane, Polyamines exemplified by trimethylene glycol-di-p-aminobenzoate, 3,5-bis (methylthio) -2,4-toluenediamine I can make it. 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 organic isocyanate, polyol, and 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, it is preferable to sufficiently remove 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.

  For example, 1) A resin sheet having a predetermined thickness is prepared from a manufactured resin block using a band saw type or canna type slicer, and the sheet is cut ( A method of forming a concavo-convex portion B for fitting with a concavo-convex portion A in an opening portion of a polishing region by patterning with a metal bite or laser, 2) optical processing (exposure development) on a resin sheet obtained by sheet molding A method of forming a concavo-convex portion B for fitting into the concavo-convex portion A of the opening of the polishing region by patterning), and 3) a mold having the shape of the concavo-convex portion B and the light transmission region A method for manufacturing by pouring light transmitting region forming material and curing, 4) A method for manufacturing by pouring light transmitting region forming material into the opening having uneven portion A of the polishing region and curing And the like. Since the engaging portion has a fine shape and is preferably in close contact with the gap as much as possible, it is desirable that the engaging portion is appropriately selected from the above-described manufacturing methods according to the characteristics of the resin used.

  The shape and size of the light transmission region are not particularly limited, but it is preferable to have the same shape and size as the opening of the polishing region.

  The thickness of the light transmission region is not particularly limited, but is preferably equal to or less than the thickness of the polishing region. Specifically, it is about 0.5 to 6 mm, preferably about 0.6 to 5 mm. If the light transmission region is thicker than the polishing region, the silicon wafer may be damaged by the protruding portion during polishing. Further, the light transmission region is deformed by the stress applied during polishing, and is greatly distorted optically, so that 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, and a large amount of slurry may accumulate, resulting in a decrease in optical end point detection accuracy.

  Further, the variation in the thickness of the light transmission region is preferably 100 μm or less, and more preferably 50 μm or less. When the thickness variation exceeds 100 μm, it has a large waviness and tends to affect the polishing characteristics because portions with different contact states with the wafer are generated.

  As a method of suppressing the variation in thickness, a method of buffing a sheet surface having a predetermined thickness can be mentioned. The buffing is preferably performed in stages using polishing sheets having different particle sizes. In addition, when buffing the light transmission region, the smaller the surface roughness, the better. When the surface roughness is large, the incident light is irregularly reflected on the surface of the light transmission region, so that the light transmittance is lowered and the detection accuracy tends to be lowered.

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

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

  The polyurethane resin is composed of organic isocyanate, polyol (high molecular weight polyol or low molecular weight polyol), and chain extender.

  The organic isocyanate to be used is not particularly limited, and examples thereof include the organic isocyanate.

  The high molecular weight polyol to be used is not particularly limited, and examples thereof include the high molecular weight polyol. In addition, the number average molecular weight of these high molecular weight polyols is not particularly limited, but is preferably 500 to 2000 from the viewpoint of the elastic characteristics of the obtained polyurethane. 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. Therefore, the polishing pad manufactured from this polyurethane becomes too hard and 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, so that a polishing pad produced from this polyurethane tends to have poor planarization characteristics.

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

  Further, the ratio of the high molecular weight polyol to the low molecular weight polyol in the polyol is determined by the characteristics required for the polishing region produced therefrom.

  Examples of chain extenders include polyamines exemplified by 4,4′-methylenebis (o-chloroaniline), 2,6-dichloro-p-phenylenediamine, 4,4′-methylenebis (2,3-dichloroaniline) and the like. Or the low molecular weight polyols mentioned above. These may be used alone or in combination of two or more.

  The ratio of the organic isocyanate, polyol, and chain extender in the polyurethane resin can be variously changed depending on the molecular weight of each and the desired physical properties of the polishing region produced therefrom. In order to obtain a polishing region having excellent polishing characteristics, 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, and more preferably Is 0.99 to 1.10.

  The polyurethane resin can be produced by a method similar to the above method. If necessary, stabilizers such as antioxidants, surfactants, lubricants, pigments, fillers, antistatic agents, and other additives may be added to the polyurethane resin.

  The polyurethane resin used in the polishing region 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 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 and does not have an active hydrogen group is preferable. Examples of the silicone surfactant include SH-192 (manufactured by Toray Dow Corning Silicon) and the like as a suitable compound.

  An example of a method for producing a closed cell type polyurethane resin foam used in the polishing region will be described below. The manufacturing method of this polyurethane resin foam has the following processes.

1) Stirring step for producing a cell dispersion of isocyanate-terminated prepolymer A silicone-based surfactant is added to the isocyanate-terminated prepolymer and stirred with a non-reactive gas to disperse the non-reactive gas as fine bubbles. A dispersion is obtained. When the isocyanate-terminated prepolymer is solid at room temperature, it is preheated to an appropriate temperature and melted before use.

2) Curing Agent (Chain Extender) Mixing Step A chain extender is added to the above cell dispersion and mixed and stirred.

3) Curing step An isocyanate-terminated prepolymer mixed with a chain extender is cast and cured by heating.

  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 method for producing the polyurethane fine foam, heating and post-curing the foam that has reacted until the foam dispersion does not flow by pouring the cell dispersion into the mold has the effect of improving the physical properties of the foam, Very suitable. The bubble dispersion may be poured into the mold and immediately placed in a heating oven for post-cure. Under such conditions, heat is not immediately transferred to the reaction components, so the bubble diameter does not increase. . The curing reaction is preferably performed at normal pressure because the bubble shape is stable.

  In the production of the polyurethane resin, a catalyst that promotes a known polyurethane reaction such as tertiary amine or organotin 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 resin foam may be manufactured by a batch method in which each component is weighed and charged into a container and stirred. In addition, each component and a non-reactive gas are continuously supplied to a stirring device and stirred. Alternatively, a continuous production method in which a foam dispersion is sent out to produce a molded product may be used.

  The polishing region to be the polishing layer is manufactured by cutting the polyurethane resin foam produced as described above into a predetermined size.

  In the polishing region of the present invention, it is preferable that a groove for holding and renewing the slurry is provided on the polishing side surface in contact with the wafer. When the polishing region is formed of fine foam, it has many openings on the polishing surface and has the function of holding the slurry, but in order to more efficiently maintain the slurry and renew the slurry. Also, it is preferable to have a groove on the surface on the polishing side in order to prevent dechucking error due to wafer adsorption, destruction of the wafer, and reduction in polishing efficiency. The groove is not particularly limited as long as it is a surface shape that holds and renews the slurry. For example, XY lattice grooves, concentric circular grooves, through holes, non-through holes, polygonal columns, cylinders, spiral grooves, Examples include eccentric circular grooves, radial grooves, and combinations of these grooves. Further, the groove pitch, groove width, groove depth and the like are not particularly limited and are appropriately selected and formed. In addition, these grooves are generally regular, but the groove pitch, groove width, groove depth, etc. may be changed for each range to make the slurry retention and renewability desirable. Is possible.

  The method of forming the groove is not particularly limited. For example, a method of machine cutting using a jig such as a tool of a predetermined size, a method of pouring and curing a resin in a mold having a predetermined surface shape , A method of pressing a resin with a press plate having a predetermined surface shape, a method of forming using photolithography, a method of forming using a printing technique, and a laser beam using a carbon dioxide gas laser, etc. The method of doing is mentioned.

  The thickness of the polishing region is not particularly limited, but is preferably about the same thickness as the light transmission region. As a method of producing the polishing region of the thickness, a method of making the block of the fine foam a predetermined thickness using a band saw type or a canna type slicer, pouring resin into a mold having a cavity of a predetermined thickness, and curing And a method using a coating technique or a sheet forming technique.

  Further, the variation in the thickness of the polishing region is preferably 100 μm or less, and particularly preferably 50 μm or less. When the thickness variation exceeds 100 μm, the polishing region has a large undulation, and there are different contact states with respect to the wafer, which tends to adversely affect the polishing characteristics. In order to eliminate the variation in the thickness of the polishing region, the surface of the polishing region is generally dressed with a dresser in which diamond abrasive grains are electrodeposited or fused in the initial stage of polishing, but the above range is exceeded. Things will increase dressing time and reduce production efficiency. In addition, as a method for suppressing the variation in thickness, there is also a method of buffing the surface of the polishing region having a predetermined thickness. When buffing, it is preferable to carry out stepwise with abrasive sheets having different particle sizes.

  The structure and manufacturing method of the polishing pad having the polishing region and the light transmission region of the present invention are not particularly limited, and various structures and manufacturing methods are conceivable. Specific examples thereof will be described below.

  FIGS. 3-6 is a schematic block diagram of the grinding | polishing area | region 2 in which the opening part 4 which has the uneven | corrugated | grooved part A (5a) was provided. The concavo-convex portion A only needs to have at least one concave portion and convex portion as shown in FIG. In order to more effectively prevent slurry leakage, it is preferable to have two or more concave portions and convex portions, respectively, as shown in FIGS. Moreover, in order to prevent slurry leakage more effectively, the width of the concavo-convex portion A is preferably 1.0 mm or more, and more preferably 2.0 mm or more.

  The height difference (D) between the concave and convex portions is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.2 mm or more, and particularly preferably 0.3 mm or more. When the height difference (D) is less than 0.1 mm, the slurry is likely to move through the engaging portion, and therefore slurry leakage tends to occur.

  Further, the shape of the concave portion or the convex portion is not particularly limited, and may be, for example, a rectangular shape as shown in FIGS. 3 and 4, a wave shape as shown in FIG. As shown, an acute angle shape (saw blade shape) may be used.

  Moreover, although the uneven | corrugated | grooved part A is preferable formed in the perimeter of an opening part, there may be a part in which the uneven | corrugated | grooved part A is not formed in the range which does not impair the effect of this invention.

  Moreover, the uneven | corrugated | grooved part A may be provided in the grinding | polishing surface side (refer FIG. 11), may be provided in the back surface side (refer FIGS. 3-6), and may be provided in both surfaces. When the concavo-convex portion A is provided on the polishing surface side, it is preferable to provide it on the back surface side because there is a possibility that the polishing area decreases and the polishing efficiency is lowered or the engagement portion is gradually removed due to wear.

  As a method for forming the opening having the concavo-convex portion A in a part of the polishing region, for example, 1) A resin sheet having a predetermined thickness is produced using a manufactured resin block using a band saw type or canna type slicer. And an opening part is formed in this sheet | seat by pressing using a cutting jig. Thereafter, a method of forming the concavo-convex portion A by grinding the periphery of the opening portion using a laser such as a carbonic acid laser or a tool such as a cutting tool. Examples thereof include a method of forming a molding material by pouring and curing, and 3) a method of forming an opening having an uneven portion A by optically processing a sheet-formed resin sheet. The size and shape of the opening are not particularly limited.

  FIGS. 7 to 11 have a polishing region and a light transmission region formed by engaging an uneven portion A (5a) provided around the opening and an uneven portion B (5b) provided around the light transmission region. 1 is a schematic configuration diagram of a polishing pad 1. FIG.

  As a method for producing the polishing pad of the present invention, for example, 1) fitting (fitting) a light transmission region having the concavo-convex portion B produced by the above method into an opening having the concavo-convex portion A of the polishing region produced by the above method. And 2) a method in which the light transmitting region forming material is poured into the opening having the concavo-convex portion A of the polished region produced by the above method and cured.

  Although it is preferable that the engaging portion between the uneven portion A and the uneven portion B is in close contact (contact), in the case of manufacturing by fitting as in the above 1), the uneven portion A and the uneven portion B There may be a case where a minute gap is generated at the engaging portion and slurry leakage occurs. Therefore, when manufacturing by fitting, it is preferable to provide an adhesive layer made of an adhesive containing a thermosetting resin or a photocurable resin between the uneven portion A and the uneven portion B.

  Known thermosetting resins can be used without particular limitation, but those that are cured at a relatively low temperature are preferred, such as unsaturated polyester resins, phenol resins, urea resins, melamine resins, epoxy resins, acrylic resins, polyurethane resins. Etc.

  A well-known thing can be used for a photocurable resin without a restriction | limiting in particular, For example, resin etc. which have photocurable functional groups, such as a carbon-carbon double bond, are mentioned. Examples of light to be irradiated include visible light, ultraviolet light, electron beams, and energy rays such as ArF laser light and KrF laser light. It is preferable to add a photopolymerization initiator to the photocurable adhesive.

  The adhesive layer was formed by applying an adhesive containing a thermosetting resin or a photocurable resin to the surface of the concavo-convex portion A and / or the concavo-convex portion B to form a coating film and fitting both the concavo-convex portions. It can be formed by heating or light irradiation later.

  On the other hand, in FIG. 12, a recess C (6a) is formed around the opening 4 and inside the polishing region 2, and a projection D (6b) is formed around the light transmission region 3, and the recess It is a schematic block diagram of the polishing pad 1 with which C (6a) and the convex part D (6b) are engaging.

  The polishing pad of the present invention only needs to have one concave portion C and one convex portion D, but in order to more effectively prevent slurry leakage, each has two or more concave portions C and convex portions D. It is preferable. In order to prevent slurry leakage more effectively, the width h of the concave portion C and the convex portion D is preferably 1.0 mm or more.

  Further, the shape of the recess C is not particularly limited, and for example, the bottom may be rectangular as shown in FIG. 12, the bottom may be arcuate as shown in FIG. As shown, the bottom may have an acute angle shape (saw blade shape) or the like.

  An example of another polishing pad manufacturing method of the present invention will be described below.

  First, a resin sheet having a predetermined thickness is produced from the manufactured resin block using a band saw type or canna type slicer. And an opening part is formed in this sheet | seat by pressing using a cutting jig. Thereafter, a recess C is formed by grinding the periphery of the opening and the inside of the polishing region using a laser such as a carbonic acid laser or a jig such as a cutting tool. The size and shape of the opening are not particularly limited. Thereafter, a light transmissive region forming material is poured into the opening having the concave portion C and cured to manufacture a polishing pad. According to the manufacturing method, the concave portion C and the convex portion D can be brought into close contact with each other, so that slurry leakage can be effectively prevented.

  The polishing pad of the present invention may be a laminated polishing pad 1 in which a cushion layer 7 is laminated on a polishing layer 2 composed of a polishing region and a light transmission region, as shown in FIGS.

  The cushion layer supplements the characteristics of the polishing layer. 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 wafer with minute irregularities generated during pattern formation is polished, and uniformity refers to the uniformity of the entire wafer. The planarity is improved by the characteristics of the polishing layer, and the uniformity is improved by the characteristics of the cushion layer. In the polishing pad of the present invention, the cushion layer is preferably softer than the polishing layer.

  A material for forming the cushion layer is not particularly limited. For example, a fiber nonwoven fabric such as a polyester nonwoven fabric, a nylon nonwoven fabric, and an acrylic nonwoven fabric, a resin-impregnated nonwoven fabric such as a polyester nonwoven fabric impregnated with polyurethane, a polymer resin such as polyurethane foam and polyethylene foam Examples thereof include rubber resins such as foam, butadiene rubber and isoprene rubber, and photosensitive resins.

  Examples of means for attaching the polishing layer and the cushion layer include a method in which the polishing layer and the cushion layer are sandwiched with a double-sided tape and pressed. A through-hole having the same shape as the light transmission region is preferably formed in the cushion layer or the double-sided tape having a low transmittance that affects the end point detection accuracy.

  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. Examples of the composition of the adhesive layer include rubber adhesives and acrylic adhesives. Considering the content of metal ions, an acrylic adhesive is preferable because the metal ion content is low. In addition, since the composition of the polishing layer 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.

  On the other side of the cushion layer, a double-sided tape for bonding to the platen may be provided. Examples of means for attaching the cushion layer and the double-sided tape include a method of pressing and bonding the double-sided tape to the cushion layer. In addition, it is preferable to form a through-hole having the same shape as the light transmission region on the double-sided tape having a low transmittance that affects the end point detection accuracy.

  The double-sided tape has a general configuration in which an adhesive layer is provided on both surfaces of a base material such as a nonwoven fabric or a film as described above. In consideration of peeling from the platen after using the polishing pad, it is preferable to use a film as the base material because the tape residue and the like can be eliminated. The composition of the adhesive layer is the same as described above.

  The semiconductor device is manufactured through a step of polishing the surface of the semiconductor wafer using the polishing pad. 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. 18, a polishing surface plate 8 that supports the polishing pad 1, a support table 10 (polishing head) that supports the semiconductor wafer 9, and the wafer. This is performed using a backing material for performing uniform pressurization and a polishing apparatus equipped with a supply mechanism of the abrasive 11. The polishing pad 1 is attached to the polishing surface plate 8 by attaching it with a double-sided tape, for example. The polishing surface plate 8 and the support base 10 are arranged so that the polishing pad 1 and the semiconductor wafer 9 supported on each of the polishing surface plate 8 and the support table 10 face each other, and are provided with rotating shafts 12 and 13 respectively. Further, a pressure mechanism for pressing the semiconductor wafer 9 against the polishing pad 1 is provided on the support base 10 side. In polishing, the semiconductor wafer 9 is pressed against the polishing pad 1 while rotating the polishing platen 8 and the support base 10, and polishing is performed while supplying alkaline or acidic 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 9 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.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. The evaluation items in Examples and the like were measured as follows.

(Average bubble diameter measurement)
A polishing region cut in parallel with a microtome cutter as thin as possible to a thickness of about 1 mm was used as a sample for measuring average bubble diameter. The sample was fixed on a slide glass, and using an image processing apparatus (Image Analyzer V10, manufactured by Toyobo Co., Ltd.), the total bubble diameter in an arbitrary 0.2 mm × 0.2 mm range was measured, and the average bubble diameter was calculated. .

(Specific gravity measurement)
This was performed according to JIS Z8807-1976. A polished area cut into a 4 cm × 8.5 cm strip (thickness: arbitrary) was used as a sample for measuring specific gravity, and the sample was allowed to stand for 16 hours in an environment of temperature 23 ° C. ± 2 ° C. and humidity 50% ± 5%. The specific gravity was measured using a hydrometer (manufactured by Sartorius).

(Asker D hardness measurement)
This was performed in accordance with JIS K6253-1997. A polished region cut out to a size of 2 cm × 2 cm (thickness: arbitrary) was used as a sample for hardness measurement, and was allowed to stand for 16 hours in an environment of a temperature of 23 ° C. ± 2 ° C. and a humidity of 50% ± 5%. At the time of measurement, the samples were overlapped to a thickness of 6 mm or more. The hardness was measured using a hardness meter (manufactured by Kobunshi Keiki Co., Ltd., Asker D type hardness meter).

(Measurement of compression rate and compression recovery rate)
A polishing area (polishing layer) cut into a 7 mm diameter circle (thickness: arbitrary) is used as a sample for measuring the compression rate and compression recovery rate, and left for 40 hours in an environment of temperature 23 ° C. ± 2 ° C. and humidity 50% ± 5%. did. For the measurement, a thermal analysis measuring instrument TMA (manufactured by SEIKO INSTRUMENTS, SS6000) was used to measure the compression rate and the compression recovery rate. The calculation formulas for compression ratio and compression recovery ratio are shown below.

Compression rate (%) = {(T1-T2) / T1} × 100
T1: The thickness of the polishing layer when a load of 30 kPa (300 g / cm ² ) of stress is maintained for 60 seconds from the unloaded state on the polishing layer.
T2: Polishing layer thickness when a stress load of 180 kPa (1800 g / cm ² ) is maintained for 60 seconds from the state of T1.

Compression recovery rate (%) = {(T3-T2) / (T1-T2)} × 100
T1: The thickness of the polishing layer when a load of 30 kPa (300 g / cm ² ) of stress is maintained for 60 seconds from the unloaded state on the polishing layer.
T2: Polishing layer thickness when a stress load of 180 kPa (1800 g / cm ² ) is maintained for 60 seconds from the state of T1.
T3: Thickness of the polishing layer when held for 60 seconds in a no-load state from the state of T2 and then holding a stress load of 30 kPa (300 g / cm ² ) for 60 seconds.

(Storage elastic modulus measurement)
This was performed in accordance with JIS K7198-1991. A polishing region cut into a 3 mm × 40 mm strip (thickness: arbitrary) was used as a sample for dynamic viscoelasticity measurement, and the sample was allowed to stand in a container containing silica gel for 4 days under an environmental condition of 23 ° C. The accurate width and thickness of each sheet after cutting was measured with a micrometer. For measurement, a storage elastic modulus E ′ was measured using a dynamic viscoelastic spectrometer (manufactured by Iwamoto Seisakusho, present IS Engineering Co., Ltd.). The measurement conditions at that time are shown below.
<Measurement conditions>
Measurement temperature: 40 ° C
Applied strain: 0.03%
Initial load: 20g
Frequency: 1Hz

(Water leakage evaluation)
SPP600S (manufactured by Okamoto Machine Tool Co., Ltd.) was used as a polishing apparatus, and water leakage was evaluated using the prepared polishing pad. An 8-inch dummy wafer was polished, and the vicinity of the light transmission region was visually observed every predetermined time and evaluated according to the following criteria. Table 1 shows the evaluation results. As polishing conditions, silica slurry (SS12, manufactured by Cabot) as an alkaline slurry was added at a flow rate of 150 ml / min during polishing, dress load 100 g / cm ² , polishing load 350 g / cm ² , dresser rotation speed 30 rpm, polishing The platen rotation speed was 35 rpm and the wafer rotation speed was 30 rpm.
○: No change.
X: The slurry penetrates to the double-sided tape.
XX: The light transmission region and the double-sided tape are partially peeled due to the penetration of the slurry.

[Production of light transmission region]
Production Example 1
A polyester polyol (number average molecular weight 2400) 128 parts by weight composed of adipic acid, hexanediol and ethylene glycol and 30 parts by weight of 1,4-butanediol were mixed, and the temperature was adjusted to 70 ° C. To this mixed solution, 100 parts by weight of 4,4′-diphenylmethane diisocyanate previously adjusted to 70 ° C. was added and stirred for about 1 minute. Then, the mixed solution was poured into a container kept at 100 ° C. and post-cured at 100 ° C. for 8 hours to produce a polyurethane resin. And using the produced polyurethane resin, the light transmission region (57 mm in length, 19 mm in width, having a concavo-convex portion B (difference in uneven height d: 0.1 mm, width 1 mm) as shown in FIG. 7 by injection molding. A thickness of 1.25 mm) was produced.

Production Example 2
Using the polyurethane resin produced in Production Example 1, the light transmission region (vertical height 57 mm, horizontal width having a concave-convex portion B (difference in concave and convex height d: 0.3 mm, width 2 mm) as shown in FIG. 8 by injection molding. 19 mm, thickness 1.25 mm).

Production Example 3
Using the polyurethane resin produced in Production Example 1, a light transmission region (57 mm length, horizontal width) having an uneven portion B (difference in uneven height d: 0.3 mm, width 2 mm) as shown in FIG. 9 by injection molding. 19 mm, thickness 1.25 mm).

Production Example 4
Using the polyurethane resin produced in Production Example 1, the light transmission region (vertical height 57 mm, horizontal width having a concave and convex portion B (difference in concave and convex height d: 0.3 mm, width 2 mm) as shown in FIG. 10 by injection molding. 19 mm, thickness 1.25 mm).

Production Example 5
In a container, 14790 parts by weight of toluene diisocyanate (mixture of 2,4-isomer / 2,6-isomer = 80/20), 3,930 parts by weight of 4,4′-dicyclohexylmethane diisocyanate, a number average molecular weight of 1006, and a molecular weight distribution of 1. 7 polytetramethylene glycol 25150 parts by weight and diethylene glycol 2756 parts by weight were added and heated and stirred at 80 ° C. for 120 minutes to obtain a prepolymer having an isocyanate equivalent of 2.10 meq / g. 100 parts by weight of this prepolymer was weighed in a vacuum tank, and the gas remaining in the prepolymer was degassed by reduced pressure (about 10 Torr). 29 parts by weight of 4,4′-methylenebis (o-chloroaniline) previously melted at 120 ° C. is added to the defoamed prepolymer, and rotated using a rotating / revolving mixer (manufactured by Sinky). The mixture was stirred at several 800 rpm for about 3 minutes. Then, the mixture was poured into a mold and post-cured in an oven at 110 ° C. for 9 hours to produce a light transmission region (length 57 mm, width 19 mm, thickness 1.25 mm) as shown in FIG.

Production Example 6
A light transmission region (length 57 mm, width 19 mm, thickness 1.25 mm) as shown in FIG. 2 was produced in the same manner as in Production Example 5.

[Production of polishing area]
Toluene diisocyanate (mixture of 2,4-isomer / 2,6-isomer = 80/20) 14790 parts by weight, 4,4′-dicyclohexylmethane diisocyanate 3930 parts by weight, number average molecular weight 1006 and molecular weight distribution 1.7 25150 parts by weight of polytetramethylene glycol and 2756 parts by weight of diethylene glycol were added, and the mixture was heated and stirred at 80 ° C. for 120 minutes to obtain a prepolymer having an isocyanate equivalent of 2.10 meq / g. In a reaction vessel, 100 parts by weight of the prepolymer and 3 parts by weight of a silicone-based nonionic surfactant (manufactured by Toray Dow Silicone, SH192) were mixed, and the temperature was adjusted to 80 ° C. Using a stirring blade, the mixture was vigorously stirred for about 4 minutes so that bubbles were taken into the reaction system at a rotation speed of 900 rpm. 26 parts by weight of 4,4′-methylenebis (o-chloroaniline) (Ihara Chemical amine, manufactured by Ihara Chemical Co.) previously melted at 120 ° C. was added thereto. After stirring for about 1 minute, the reaction solution was poured into a pan-type open mold. When the reaction solution lost its fluidity, it was put in an oven and post-cured at 110 ° C. for 6 hours to obtain a polyurethane resin foam block. This polyurethane resin foam block was sliced using a band saw type slicer (manufactured by Fecken) to obtain a polyurethane resin foam sheet. Next, this sheet was subjected to surface buffing to a predetermined thickness using a buffing machine (Amitech Co., Ltd.) to obtain a sheet with adjusted thickness accuracy (sheet thickness: 1.27 mm). This buffed sheet is punched into a predetermined diameter (61 cm), and a groove processing machine (manufactured by Toho Steel Machine Co., Ltd.) is used to form a groove with a groove width of 0.25 mm, a groove pitch of 1.50 mm, and a groove depth of 0.40 mm. Concentric grooves were processed. Thereafter, an opening (thickness 1.27 mm, 57.5 mm × 19.5 mm) for fitting the light transmission region into a predetermined position of the grooved sheet was punched out to produce a polishing region. The physical properties of the produced polishing region were an average bubble diameter of 45 μm, a specific gravity of 0.86, an Asker D hardness of 53 degrees, a compression rate of 1.0%, a compression recovery rate of 65%, and a storage elastic modulus of 275 MPa.

[Production of polishing pad]
Example 1
An uneven portion A (difference in uneven height d: 0.1 mm, width 1 mm) as shown in FIG. 3 is formed around the opening on the back side of the polished region using a cutting tool. The light transmission area | region which has the uneven | corrugated | grooved part B was inserted. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 2
An uneven portion A (difference in uneven height d: 0.3 mm, width 2 mm) as shown in FIG. The light transmission area | region which has the uneven | corrugated | grooved part B was inserted. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 3
An uneven portion A (difference in uneven height d: 0.3 mm, width 2 mm) as shown in FIG. 5 is formed around the opening on the back side of the polished region using a cutting tool. The light transmission area | region which has the uneven | corrugated | grooved part B was inserted. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 4
An uneven portion A (difference in uneven height d: 0.3 mm, width 2 mm) as shown in FIG. The light transmission area | region which has the uneven | corrugated | grooved part B was inserted. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 5
In a container, 14790 parts by weight of toluene diisocyanate (mixture of 2,4-isomer / 2,6-isomer = 80/20), 3,930 parts by weight of 4,4′-dicyclohexylmethane diisocyanate, a number average molecular weight of 1006, and a molecular weight distribution of 1. 7 polytetramethylene glycol 25150 parts by weight and diethylene glycol 2756 parts by weight were added and heated and stirred at 80 ° C. for 120 minutes to obtain a prepolymer having an isocyanate equivalent of 2.10 meq / g. 100 parts by weight of this prepolymer was weighed in a vacuum tank, and the gas remaining in the prepolymer was degassed by reduced pressure (about 10 Torr). 29 parts by weight of 4,4′-methylenebis (o-chloroaniline) previously melted at 120 ° C. was added to the defoamed prepolymer, and the rotation speed was 800 rpm using a rotating / revolving mixer (made by Sinky). Was stirred for about 3 minutes to prepare a polyurethane-based adhesive. A concavo-convex portion A (difference in concavo-convex height d: 0.15 mm, width 1 mm) as shown in FIG. 3 is formed around the opening on the back side of the polished region using a cutting tool. A polyurethane adhesive was applied uniformly. Then, the light transmission area | region which has the uneven | corrugated | grooved part B produced in the manufacture example 1 was engage | inserted. Then, post-curing was performed at 110 ° C. for 9 hours to cure the polyurethane adhesive and form an adhesive layer. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 6
100 parts by weight of liquid urethane acrylate (Actylane 290, manufactured by AKCROS CHEMICALS) and 1 part by weight of benzyl dimethyl ketal were stirred and mixed at a rotational speed of 800 rpm for about 3 minutes using a rotating and rotating mixer (manufactured by Sinky). A photocurable adhesive was obtained. A concavo-convex portion A (difference in concavo-convex height d: 0.15 mm, width 1 mm) as shown in FIG. 3 is formed around the opening on the back side of the polished region using a cutting tool, and light is applied to the concavo-convex portion A. A curable adhesive was applied evenly. Then, the light transmission area | region which has the uneven | corrugated | grooved part B produced in the manufacture example 1 was engage | inserted. And the ultraviolet-ray irradiation was performed from the back surface side of the grinding | polishing area | region, the photocurable adhesive agent was hardened, and the adhesive bond layer was formed. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 7
80 parts by weight of liquid urethane acrylate (Actylane 290, manufactured by Aczo Nobeles), 20 parts by weight of liquid urethane acrylate (UA-101H, manufactured by Kyoeisha Chemical Co., Ltd.), and 1 part by weight of benzyldimethyl ketal The mixture was stirred and mixed at a rotation speed of 800 rpm for about 3 minutes to obtain a liquid photocurable resin composition. A concavo-convex portion A (difference in height of concavo-convex height d: 0.1 mm) as shown in FIG. A curable resin composition was poured. Then, ultraviolet irradiation was performed from the back surface side of the polishing region to form a light transmission region having the uneven portion B. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Example 8
A recess C (concave depth h: 1.0 mm) as shown in FIG. 12 was formed by using a cutting tool in the vicinity of the opening of the prepared polishing region and in the polishing region. On the other hand, 128 parts by weight of polyester polyol (number average molecular weight 2400) composed of adipic acid, hexanediol and ethylene glycol and 30 parts by weight of 1,4-butanediol were mixed, and the temperature was adjusted to 70 ° C. To this mixed solution, 100 parts by weight of 4,4′-diphenylmethane diisocyanate previously adjusted to 70 ° C. was added and stirred for about 1 minute to prepare a light transmission region forming material. Then, the light transmission region forming material was poured into the opening having the concave portion C, and post curing was performed at 100 ° C. for 8 hours to form a light transmission region (thickness 1.25 mm) having the convex portion D. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Comparative Example 1
The light transmission region produced in Production Example 5 was fitted into the opening of the produced polishing region. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

Comparative Example 2
A recess as shown in FIG. 2 was formed around the opening on the back side of the manufactured polishing region using a cutting tool, and the light transmission region prepared in Production Example 6 was fitted. Then, a double-sided tape (Sekisui Chemical Co., Ltd., double tack tape) was bonded to the back side of the polishing area with a laminator.

表１から明らかなように、本発明の研磨パッドを用いることにより、研磨領域と光透過領域との間からのスラリー漏れを長時間防止することができる。

As is apparent from Table 1, by using the polishing pad of the present invention, it is possible to prevent slurry leakage from between the polishing region and the light transmission region for a long time.

FIG. 6 is a schematic cross-sectional view showing an example of a conventional polishing pad. FIG. 6 is a schematic cross-sectional view showing an example of a conventional polishing pad. The schematic sectional drawing which shows an example of the grinding | polishing area | region provided with the opening part which has the uneven | corrugated | grooved part A of this invention. The schematic sectional drawing which shows an example of the grinding | polishing area | region provided with the opening part which has the uneven | corrugated | grooved part A of this invention. The schematic sectional drawing which shows an example of the grinding | polishing area | region provided with the opening part which has the uneven | corrugated | grooved part A of this invention. The schematic sectional drawing which shows an example of the grinding | polishing area | region provided with the opening part which has the uneven | corrugated | grooved part A of this invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. 1 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. The schematic sectional drawing which shows an example of the polishing pad (lamination | stacking type) of this invention. The schematic sectional drawing which shows an example of the polishing pad (lamination | stacking type) of this invention. The schematic sectional drawing which shows an example of the polishing pad (lamination | stacking type) of this invention. The schematic block diagram which shows an example of the grinding | polishing apparatus used by CMP grinding | polishing.

Explanation of symbols

1: Polishing pad 2: Polishing area 3: Light transmission area 4: Opening 5a: Concavity and convexity A
5b: Concavity and convexity B
6a: Recess C
6b: Convex D
7: Cushion layer 8: Polishing surface plate 9: Semiconductor wafer 10: Support base 11: Polishing agent 12, 13: Rotating shaft

Claims (5)

In a polishing pad having a polishing region and a light transmission region, the polishing region has an opening for providing a light transmission region, and an uneven portion A is formed around the opening, and the light transmission A polishing pad, wherein a concavo-convex portion B is formed around the region, and the concavo-convex portion A and the concavo-convex portion B are engaged with each other. The polishing pad according to claim 1, wherein an adhesive layer made of an adhesive containing a thermosetting resin is provided between the uneven portion A and the uneven portion B. The polishing pad according to claim 1, wherein an adhesive layer made of an adhesive containing a photocurable resin is provided between the concavo-convex portion A and the concavo-convex portion B. In a polishing pad having a polishing region and a light transmission region, the polishing region has an opening for providing a light transmission region, and a recess C is formed around the opening and inside the polishing region. A polishing pad, wherein a convex portion D is formed around the light transmission region, and the concave portion C and the convex portion D are engaged. A method for manufacturing a semiconductor device, comprising a step of polishing a surface of a semiconductor wafer using the polishing pad according to claim 1.

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