JP2007260827A - Method of manufacturing polishing pad - Google Patents

Method of manufacturing polishing pad Download PDF

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JP2007260827A
JP2007260827A JP2006087985A JP2006087985A JP2007260827A JP 2007260827 A JP2007260827 A JP 2007260827A JP 2006087985 A JP2006087985 A JP 2006087985A JP 2006087985 A JP2006087985 A JP 2006087985A JP 2007260827 A JP2007260827 A JP 2007260827A
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polishing
region
method
polishing pad
step
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Atsushi Kazuno
Takeshi Kimura
Yoshiyuki Nakai
Kazuyuki Ogawa
Tetsuo Shimomura
哲生 下村
良之 中井
一幸 小川
淳 数野
毅 木村
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Toyo Tire & Rubber Co Ltd
東洋ゴム工業株式会社
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/10General improvement of production processes causing greenhouse gases [GHG] emissions
    • Y02P20/14Reagents; Educts; Products
    • Y02P20/147Using materials efficiently
    • Y02P20/149Reduced process losses

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polishing pad capable of preventing slurry leakage and having excellent optical detection accuracy.
SOLUTION: A step of producing a polishing region 9 made of polyurethane foam, a step of forming an opening 14 made of a through hole 12 and a shelf 13 in the polishing region, a convex light transmission region thinner than the polishing region The manufacturing method of the polishing pad 8 including the process of producing 10, the process of installing the said light transmissive area | region in the opening part of the said grinding | polishing area, and the process of bonding the transparent support film 11 on the grinding | polishing back surface side of the said grinding | polishing area | region.
[Selection] Figure 2

Description

  The present invention stabilizes flattening processing of 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 processing, The present invention also relates to a method of manufacturing a polishing pad that can be performed with high polishing efficiency. The polishing pad obtained by the production method of the present invention is particularly suitable for a silicon wafer and a device on which an oxide layer, a metal layer, etc. are formed, and further flattened before laminating and forming these oxide layers and metal layers. It is suitably used in the process of converting.

  When manufacturing a semiconductor device, a step of forming a conductive layer on the wafer surface and forming a wiring layer by photolithography, etching, or the like, or a step of forming an interlayer insulating film on the wiring layer These steps 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, 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 an abrasive 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.

  Conventionally, such a polishing pad is produced by 1) pouring a resin material into a mold to produce a resin block, and slicing the resin block with a slicer, and 2) pouring the resin material into the mold and pressing it. Thus, it has been produced by a batch method such as a method for producing a thin sheet, and 3) a method in which a resin as a raw material is dissolved and extruded from a T-die and directly produced into a sheet. For example, in Patent Document 1, a polishing pad is manufactured by a reaction injection molding method.

  In addition, in the case of a laminated polishing pad, since it was manufactured by bonding a plurality of resin sheets such as a polishing layer and a cushion layer obtained by the above method with an adhesive or a double-sided tape, there are many manufacturing steps and productivity is poor. Had the problem. In order to solve the problem, in Patent Document 2, a laminated polishing pad is manufactured using an extruder.

  In addition, a method for continuously producing a polyurethane / polyurea abrasive sheet material has been proposed in order to prevent variations in hardness, bubble size, and the like due to a batch production method (Patent Document 3). Specifically, a polyurethane raw material is mixed with a fine powder having a particle size of 300 μm or less and an organic foaming agent, and the mixture is discharged and cast between a pair of endless track belts. Thereafter, a polymerization reaction of the mixture is performed by a heating means, and the produced sheet-like molded product is separated from the face belt to obtain an abrasive sheet material.

  On the other hand, a polyurethane foam sheet is generally used as a polishing pad used for high-precision polishing. However, although the polyurethane foam sheet is excellent in local flattening ability, it is difficult to apply a uniform pressure to the entire wafer surface because of insufficient cushioning properties. For this reason, usually, a soft cushion layer is separately provided on the back surface of the polyurethane foam sheet, and is used for polishing as a laminated polishing pad. For example, the following polishing pads have been developed.

  A polishing pad is disclosed in which a relatively hard first layer and a relatively soft second layer are laminated, and a groove having a predetermined pitch or a protrusion having a predetermined shape is provided on the polishing surface of the first layer. (Patent Document 4).

  Also, a first sheet-like member having elasticity and having irregularities formed on the surface, and a surface that is provided on the surface of the first sheet-like member on which irregularities are formed and that faces the surface to be polished of the substrate to be processed A polishing cloth having a second sheet-like portion is disclosed (Patent Document 5).

  Furthermore, a polishing pad is disclosed that includes a polishing layer and a support layer that is laminated on one surface of the polishing layer and is a foam having a higher compressibility than the polishing layer (Patent Document 6).

  However, since the conventional laminated polishing pad is manufactured by bonding the polishing layer and the cushion layer with a double-sided tape (adhesive layer), the slurry enters between the polishing layer and the cushion layer during polishing. As a result, the adhesive force of the double-sided tape is weakened, and as a result, the polishing layer and the cushion layer are peeled off.

  Further, when performing 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 7 and 8) are becoming mainstream.

  Specifically, the optical detection means detects a polishing end point 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.

  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 10). Moreover, a polishing pad having a transparent plug that is flush with the polishing surface is disclosed (Patent Document 11).

  On the other hand, proposals (Patent Documents 12 and 13) have been made to prevent the slurry from leaking from the boundary (seam) between the polishing region and the light transmission region.

  In addition, the first resin rod or plug is placed in the liquid second resin, the second resin is cured to produce a molded product, and the molded product is sliced to polish the light transmission region and the polished product. A method of manufacturing a polishing pad in which regions are integrated is disclosed (Patent Document 14). However, since the above manufacturing method is a method in which the transparent plug is inserted into the opaque resin and cured while the opaque resin is still liquid, excessive pressure or stress is applied from the opaque resin to the transparent plug when the opaque resin is cured. May cause residual stress deformation or swelling of the transparent plug. Due to this residual stress deformation or swelling, the flatness of the transparent plug is impaired, causing a problem in optical detection accuracy. In addition, stress due to the difference in thermal shrinkage between the two materials remains at the bonding interface between the two materials at the time of molding, and slurry leakage may occur due to easy peeling at the bonding interface.

  Moreover, in order to prevent a slurry leak, the method of arrange | positioning the transparent film with which the adhesive agent was apply | coated to the upper and lower surfaces between the upper layer pad and the lower layer pad is disclosed (patent document 15). However, if there is an adhesive layer between the light transmission region and the transparent film, the light transmittance is lowered, so that the optical detection accuracy may be lowered.

JP 2004-42189 A JP 2003-220550 A JP 2004-169038 A JP 2003-53657 A JP-A-10-329005 JP 2004-25407 A US Pat. No. 5,069,002 US Pat. No. 5,081,421 Japanese National Patent Publication No. 11-512977 Japanese Patent Laid-Open No. 9-7985 Japanese Patent Laid-Open No. 10-83977 JP 2001-291686 A Japanese translation of PCT publication No. 2003-510826 JP 2005-210143 A JP 2003-68686 A

  An object of this invention is to provide the method of manufacturing the polishing pad which can prevent a slurry leak and is excellent in optical detection precision.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above object can be achieved by the following polishing pad manufacturing method, and have completed the present invention.

  That is, the polishing pad manufacturing method of the present invention includes a step of producing a polishing region made of polyurethane foam, a step of forming an opening made of a through hole and a shelf in the polishing region, and a convex shape thinner than the polishing region. Forming a light transmissive region, placing the light transmissive region in the opening of the polishing region, and attaching a transparent support film to the polishing back surface of the polishing region.

  According to the said manufacturing method, since a light transmissive area | region and a grinding | polishing area | region are shape | molded on the transparent support film, a slurry does not leak below a transparent support film at the time of grinding | polishing. Moreover, since the polishing pad of the present invention has a space between the light transmission region and the transparent support film, it is optical compared to the case where the light transmission region and the support film are bonded together using an adhesive. Excellent detection accuracy. In the polishing pad of the present invention, a cushion layer may be laminated on one side of the transparent support film.

  The thickness of the thickest part of the light transmission region is preferably 50 to 90% of the thickness of the polishing region from the viewpoint of strength and light transmittance. If it is less than 50%, the light transmission region disappears or becomes too thin due to wear due to long-term use of the polishing pad, optical detection becomes impossible, and optical detection accuracy tends to decrease due to slurry leakage. It is in. On the other hand, if it exceeds 90%, the back surface of the light transmission region may come into contact with the adhesive layer for laminating the transparent support film during production, which is not preferable for production.

  The light transmission region is preferably made of a thermosetting resin, particularly preferably a thermosetting polyurethane resin.

  The present invention also relates to a polishing pad manufactured by the above method, and a method of manufacturing a semiconductor device including a step of polishing a surface of a semiconductor wafer using the polishing pad.

  The method for producing a polishing pad according to the present invention includes a step of producing a polishing region made of polyurethane foam, a step of forming an opening made of a through hole and a shelf in the polishing region, and a convex light that is thinner than the polishing region. A step of producing a transmission region, a step of installing the light transmission region in an opening of the polishing region, and a step of bonding a transparent support film to the polishing back surface side of the polishing region.

  FIG. 2 is a cross-sectional view of the polishing pad of the present invention. The polishing region 9 is made of a polyurethane foam having fine bubbles. Polyurethane is preferred 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 polyurethane is composed of an isocyanate component, a polyol component (high molecular weight polyol, low molecular weight polyol), and a chain extender.

  As the isocyanate component, a known compound in the field of polyurethane can be used without particular limitation. As the isocyanate component, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, etc. Aliphatic diisocyanate, 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate Isocyanate, alicyclic diisocyanates such as norbornane diisocyanate. These may be used alone or in combination of two or more.

  As the isocyanate component, a trifunctional or higher polyfunctional polyisocyanate compound can be used in addition to the diisocyanate compound. 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.).

  Of the above isocyanate components, it is preferable to use an aromatic diisocyanate and an alicyclic diisocyanate in combination, and it is particularly preferable to use toluene diisocyanate and dicyclohexylmethane diisocyanate in combination.

  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.

  The number average molecular weight of the high molecular weight polyol is not particularly limited, but is preferably 500 to 2000 from the viewpoint of the elastic properties of the resulting polyurethane resin. When the number average molecular weight is less than 500, a polyurethane resin using the number average molecular weight does not have sufficient elastic properties and becomes a brittle polymer. For this reason, the polishing region manufactured from this polyurethane resin 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 2000, a polyurethane resin using the number average molecular weight becomes too soft, and a polishing region produced from the polyurethane resin tends to be inferior in flattening characteristics.

  In addition to the above-described high molecular weight polyol as a polyol component, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4 -It is preferable to use a low molecular weight polyol such as cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-bis (2-hydroxyethoxy) benzene or the like. Low molecular weight polyamines such as ethylenediamine, tolylenediamine, diphenylmethanediamine and diethylenetriamine may be used.

  The ratio of the high molecular weight polyol to the low molecular weight polyol in the polyol component is determined by the characteristics required for the polishing region produced from these.

  When a polyurethane foam is produced by a prepolymer method, a chain extender is used for curing the prepolymer. The chain extender is an organic compound having at least two active hydrogen groups, and examples of the active hydrogen group include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH). Specifically, 4,4′-methylenebis (o-chloroaniline) (MOCA), 2,6-dichloro-p-phenylenediamine, 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, 1,2-bis (2-aminophenylthio) ethane, 4,4′-diamino-3,3′-diethyl-5,5′-dimethyl Diphenylmethane, N, N′-di-sec-butyl-4,4′-diaminodiphenylmethane, 3,3′-diethyl-4,4′-diaminodiphenylmethane, m-xyl And polyamines exemplified by N, N'-di-sec-butyl-p-phenylenediamine, m-phenylenediamine, and p-xylylenediamine, or the above-mentioned low molecular weight polyols and low molecular weight polyamines. be able to. 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 can be variously changed depending on the molecular weight of each and the desired physical properties of the polishing region. In order to obtain a polishing region having desired polishing characteristics, the number of isocyanate groups of the isocyanate component relative to the total number of active hydrogen groups (hydroxyl group + amino group) of the polyol component and the chain extender is 0.80 to 1.20. Is more preferable, and 0.99 to 1.15 is more preferable. When the number of isocyanate groups is outside the above range, curing failure occurs and the required specific gravity and hardness cannot be obtained, and the polishing characteristics tend to be deteriorated.

  Polyurethane foam can be produced by either the prepolymer method or the one-shot method, but a prepolymer in which an isocyanate-terminated prepolymer is synthesized from an isocyanate component and a polyol component in advance and then reacted with a chain extender. The method is suitable because the physical properties of the resulting polyurethane are excellent.

  Examples of the method for producing the polyurethane foam include a method of adding hollow beads, a mechanical foaming method, a chemical foaming method, and the like.

  In particular, a mechanical foaming method using a silicone surfactant which is a copolymer of polyalkylsiloxane and polyether and does not have an active hydrogen group is preferable. Examples of the silicon surfactant include SH-192, L-5340 (manufactured by Toray Dow Corning Silicon) and the like as suitable compounds.

An example of a method for producing a polishing region made of polyurethane foam will be described below. The manufacturing method of such a polishing region includes the following steps.
1) Foaming process for producing a cell dispersion of isocyanate-terminated prepolymer A silicon-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 step The above foaming reaction solution is poured into a mold.
4) Curing step The foaming reaction solution poured into the mold is heated to cause reaction curing.

  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. In view of cost, it is most preferable to use air that has been dried to remove moisture.

  A known stirring device can be used without particular limitation as a stirring device for dispersing non-reactive gas in the form of fine bubbles and dispersed in the first component containing the silicon-based surfactant. Specifically, a homogenizer, a dissolver, 2 A shaft 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 cell dispersion in a foaming 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 foaming 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 a long mold and immediately put into a heating oven for post cure, and since heat is not immediately transferred to the reaction components even under such conditions, the bubble diameter may increase. Absent. The curing reaction is preferably performed at normal pressure because the bubble shape is stable.

  Polyurethane foam can be produced by weighing each component, putting it in a container and stirring it, or by continuously supplying each component and non-reactive gas to the stirrer and stirring to disperse the bubbles. It may be a continuous production method in which the liquid is produced while being sent out.

  In addition, a prepolymer as a raw material for polyurethane foam is put into a reaction vessel, and then a chain extender is added, stirred, and then poured into a mold of a predetermined size to produce a block. The block is shaped like a bowl or a band saw A thin sheet may be formed by a method of slicing using a slicer or the above-mentioned mold stage. Alternatively, a raw material resin may be dissolved and extruded from a T-die to directly obtain a sheet-like polyurethane foam.

  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 of the polished material (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 material 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 polyurethane foam preferably has a hardness of 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 material to be polished is lowered. When the Asker D hardness is more than 70 degrees, the planarity is good but the uniformity of the material to be polished is lowered. There is a tendency.

  The polishing surface that comes into contact with the material to be polished in the polishing region preferably has a concavo-convex structure for holding and renewing the slurry. The polishing area made of foam has many openings on the polishing surface and has the function of holding and updating the slurry. By forming a concavo-convex structure on the polishing surface, the slurry can be held and updated more efficiently. It can be performed well, and destruction of the material to be polished due to adsorption with the material to be polished can be prevented. The concavo-convex structure is not particularly limited as long as it is a shape that holds and renews the slurry. For example, an XY lattice groove, a concentric circular groove, a through hole, a non-penetrating hole, a polygonal column, a cylinder, a spiral groove, Examples include eccentric circular grooves, radial grooves, and combinations of these grooves. In addition, these uneven structures are generally regular, but in order to make the slurry retention and renewability desirable, the groove pitch, groove width, groove depth, etc. should be changed for each range. Is also possible.

  Although the thickness of a grinding | polishing area | region is not specifically limited, Usually, it is about 0.8-4 mm, and it is preferable that it is 1.5-2.5 mm. As a method for producing the polishing region of the thickness, a method of making the foam block a predetermined thickness using a band saw type or canna type slicer, a method of pouring a resin into a mold having a cavity of a predetermined thickness, and curing it And a method using a coating technique or a sheet forming technique.

  The thickness variation in the polishing region is preferably 100 μm or less. When the thickness variation exceeds 100 μm, the polishing region has a large undulation, and there are portions where the contact state with the material to be polished is different, which adversely affects the polishing characteristics. In order to eliminate the variation in the thickness of the polishing region, in general, the polishing surface is dressed with a dresser in which diamond abrasive grains are electrodeposited and fused in the initial stage of polishing. The dressing time becomes longer and the production efficiency is lowered.

  As a method for suppressing the thickness variation in the polishing region, a method of buffing the surface with a buffing machine can be mentioned. In addition, when buffing, it is preferable to perform in stages with abrasives having different particle sizes.

  Although the magnitude | size of a grinding | polishing area | region can be suitably adjusted according to the grinding | polishing apparatus to be used, a diameter is about 30-120 cm normally.

  Thereafter, an opening 14 composed of a through hole 12 and a shelf 13 is formed in the polishing region 9. The position and number of openings are not particularly limited, but when the polishing region 9 is circular, one is preferably formed between the center and the peripheral edge. The shapes of the through hole 12 and the shelf 13 are not particularly limited, but are preferably rectangular.

  As a method for forming the opening 14, for example, 1) a polyurethane foam at a predetermined position is punched with a Thomson blade or the like to form the through hole 12, and the periphery of the through hole 12 is cut with a cutting tool or the like to form the shelf 13 Forming method 2) A polyurethane foam at a predetermined position is cut to the depth of the shelf 13 by the width of the opening 14 to form a groove, and then the polyurethane foam inside the groove is punched and penetrated by the width of the through hole 12 Examples thereof include a method of forming the holes 12 and the shelf 13, and 3) a method of using a mold having the shape of the opening 14.

  The width and length of the through-hole 12 are not particularly limited, but are usually about 10 to 30 mm in width and about 40 to 70 mm in length. Moreover, although the width | variety and depth of the shelf part 13 are not restrict | limited in particular, Usually, a width | variety is about 2-5 mm and a depth is about 50 to 80% of the thickness of a grinding | polishing area | region.

  The material for forming the light transmission region 10 is not particularly limited, but a material that enables high-precision optical end point detection while polishing and has a light transmittance of 40% or more over the entire wavelength range of 300 to 800 nm is used. It is preferable that the material has a light transmittance of 50% or more. Examples of such materials include thermosetting resins such as polyurethane resins, polyester resins, phenol resins, urea resins, melamine resins, epoxy resins, and acrylic 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. Among these, it is preferable to use a thermosetting resin, and it is particularly preferable to use a thermosetting polyurethane resin.

  The convex light transmission region 10 can be produced by, for example, an extrusion molding method or a casting molding method. Further, as shown in FIG. 3, a convex and rectangular light transmission region 10 can be efficiently produced by applying a number of grooves to the resin sheet 15 at predetermined intervals and then cutting the resin sheet 15 at the center of the groove 16. . FIG. 4 is a cross-sectional view of the resin sheet 15 cut in the X direction. It is preferable that the width and height of the shoulder portion 17 in the light transmission region 10 correspond to the width and depth of the shelf portion 13 in the polishing region. Further, it is preferable that the width and length of the head portion 18 also correspond to the width and length of the through hole 12 in the polishing region 9. The width of the head portion 18 is usually about 10 to 30 mm, and the length is usually about 40 to 70 mm. In addition, the thickness (h) of the thickest portion of the light transmission region 10 needs to be at least thinner than the thickness of the polishing region 9, and is preferably 50 to 90% of the thickness of the polishing region. Is 60-85%.

  The transparent support film used in the present invention is not particularly limited, but is preferably a resin film having high transparency, heat resistance and flexibility. Examples of the material of the resin film include: polyester; polyethylene; polypropylene; polystyrene; polyimide; polyvinyl alcohol; polyvinyl chloride; And special engineering plastics such as polyetheretherketone and polyethersulfone.

  The thickness of the transparent support film is not particularly limited, but is preferably about 20 to 200 μm from the viewpoints of strength and winding.

  In the polishing pad 8 of the present invention, the light transmission region 10 is installed in the opening 14 of the polishing region 9 (step A), and the transparent support film 11 is bonded to the polishing back surface side of the polishing region 9 (step B). ). Note that either of the processes A and B may be performed first or simultaneously.

  When installing the light transmission region 10 in the opening portion 14, it is preferable to bond the shelf portion 13 and the shoulder portion 17 via the adhesive layer 20. Thereby, the infiltration of the slurry can be completely prevented. A known adhesive can be used as the raw material for the adhesive layer 20 without any particular limitation, but a hot melt adhesive is preferably used from the viewpoints of automation, high speed, and labor saving of the work process. In particular, it is preferable to use an EVA-based or synthetic rubber-based hot melt adhesive having excellent adhesiveness and a low softening point.

  The bonding method is not particularly limited. For example, after applying a hot-melt adhesive on the shelf 13 in the polishing region 9 and installing the light transmission region 10 in the opening 14, light is applied using a nip roll with a heater. This can be done by heating and pressing the transmission region. The heating temperature is appropriately adjusted in consideration of the softening point of the hot melt adhesive. The hot melt adhesive may be applied to the shoulder portion of the light transmission region.

  Examples of means for attaching the transparent support film 11 to the polishing back surface side of the polishing region 9 include, for example, a method of sandwiching and pressing the polishing region 9 and the transparent support film 11 with a double-sided tape 20, and a polishing back surface side of the polishing region 9 For example, a method may be used in which an adhesive is applied and the transparent support film 11 is bonded.

  The polishing pad 8 of the present invention may be a laminate of the polishing layer produced by the above method and a cushion sheet (cushion layer) 21.

  The cushion sheet supplements the characteristics of the polishing layer. The cushion sheet is necessary for achieving 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 sheet. In the polishing pad of the present invention, it is preferable to use a cushion sheet that is softer than the polishing region.

  Examples of the cushion sheet include 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 foam such as polyurethane foam and polyethylene foam, a butadiene rubber, Examples thereof include rubber resins such as isoprene rubber and photosensitive resins.

  Examples of means for attaching the polishing layer and the cushion sheet include a method of laminating and pressing a transparent support film and a cushion sheet via a double-sided tape.

  As for the polishing pad 8 of this invention, the double-sided tape 20 may be provided in the surface side adhere | attached with the platen of the transparent support film 11 or the cushion layer 21. FIG.

  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. 1, a polishing surface plate 2 that supports the polishing pad 1, a support table (polishing head) 5 that supports the semiconductor wafer 4, and the wafer. This is performed using a backing material for performing uniform pressurization and a polishing apparatus equipped with a polishing agent 3 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 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.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1
100 parts by weight of an isocyanate-terminated prepolymer (Uniroyal, Adiprene L-325) adjusted to 70 ° C. and 3 parts by weight of a silicon-based surfactant (Toray Dow Corning Silicone, SH-192) were added to the container. The mixture was mixed, adjusted to 80 ° C., and degassed under reduced pressure. Thereafter, using a biaxial mixer, the mixture was vigorously stirred for about 4 minutes so that air bubbles were taken into the container at a rotation speed of 900 rpm. Thereto, 26.2 parts by weight of 4,4′-methylenebis (o-chloroaniline) (Ihara Chemical Co., Ltd., Cuamine MT) previously melted at 120 ° C. was added, and the mixture was stirred for about 70 seconds to effect foaming reaction. A liquid was prepared. Thereafter, the foaming reaction liquid was poured into a pan-type open mold (casting container). When the flowability of the foaming reaction liquid disappeared, it was put in an oven and post-cured at 80 to 85 ° C. for 12 hours to obtain a polyurethane foam block.

  The polyurethane foam block heated to 80 ° C. was sliced using a slicer (AGW, manufactured by VGW-125), and a polyurethane foam sheet (average cell diameter: 50 μm, specific gravity: 0.86, hardness: 52 degrees) was obtained. Obtained. Next, using a buffing machine (Amitech Co., Ltd.), the surface of the sheet was buffed to a thickness of 1.3 mm to obtain a sheet with adjusted thickness accuracy. The buffed sheet is cut into a 51 cm diameter using a K (concentric circle) groove processing machine (manufactured by Techno), and the sheet surface has a groove width of 0.25 mm, a groove pitch of 1.50 mm, and a groove depth of 0. A 40 mm concentric groove was formed to produce a polished region. Thereafter, a polyurethane foam at a predetermined position in the polishing region is punched out with a Thomson blade to form a through hole (width 20 mm, length 60 mm), and a shelf is formed around the through hole using a groove processing machine (manufactured by Techno). Part (width 3.5 mm, depth 0.6 mm) was formed.

  70 parts by weight of isocyanate-terminated prepolymer (manufactured by Nippon Polyurethane Co., Ltd., C-2612) whose temperature was adjusted to 80 ° C., 9 parts by weight of trimethylolpropane, and 21 parts by weight of polytetramethylene ether glycol having a number average molecular weight of 650 were mixed and removed. A light transmitting region forming material was prepared by bubbling. The light transmission region forming material was poured into a mold (width 80 cm, length 80 cm, height 3 cm). When the fluidity of the material disappeared, it was put in an oven and post-cured at 100 to 105 ° C. for 12 hours to obtain a non-foamed sheet. Next, the surface of the sheet was buffed using a buffing machine (manufactured by Amitech Co., Ltd.) until the thickness became 0.9 mm, to obtain a sheet with adjusted thickness accuracy. Then, using a groove processing machine (manufactured by Techno), a longitudinal groove having a groove width of 6 mm, a groove pitch of 25 mm, and a groove depth of 0.6 mm, a groove width of 6 mm, a groove pitch of 65 mm, and a groove depth is formed on the entire surface of the non-foamed sheet. A 0.6 mm lateral groove was formed. Thereafter, all the grooves were cut at the central portion of the groove to produce a large number of light transmission regions (shoulder portion: width 3 mm, height 0.6 mm, head portion: width 19 mm, length 59 mm, height 0.9 mm). .

  A hot melt adhesive (Okamoto Naka Shoji Co., Ltd., Super Tech 1942, EVA system, softening point 88 ° C., 4000 cps at 177 ° C.) was applied to the shoulder portion of the produced light transmission region and left at room temperature for about 1 hour. Thereafter, the light transmission region is disposed in the opening of the polishing region, and the light transmission region is heated and pressed using a nip roll whose temperature is adjusted to 100 ° C., and the light transmission region and the polishing region are bonded to obtain a polishing sheet. . Then, the double-sided tape (Sekisui Chemical Co., Ltd. product # 5782W) was affixed on the surface on the opposite side to the groove process surface of an abrasive sheet using the laminating machine. And the said double-sided tape of the position corresponding to a light transmissive area | region was cut off with NT cutter. Then, a transparent support film (Toyobo Co., Ltd., E5001, PET film, thickness 75 μm) was bonded to the double-sided tape using a laminator to prepare a polishing layer.

  Furthermore, a double-sided tape (Sekisui Chemical Co., Ltd., # 5782W) was bonded to both surfaces of a corona-treated cushion sheet (Toray Industries, polyethylene foam, Torepef, thickness 0.8 mm). And the polyethylene foam and double-sided tape of the position corresponding to a light transmissive area | region were pierced with the Thomson blade. Then, the double-sided tape of the said cushion sheet was bonded together to the said grinding | polishing layer, and the polishing pad was produced.

Schematic configuration diagram showing an example of a polishing apparatus used in CMP polishing Schematic which shows an example of the cross section of the polishing pad of this invention Schematic showing an example of a resin sheet in which many grooves are formed at a predetermined interval Schematic showing an example of a cross section when the resin sheet is cut in the X direction

Explanation of symbols

1: Polishing pad 2: Polishing surface plate 3: Abrasive (slurry)
4: Material to be polished (semiconductor wafer)
5: Support base (polishing head)
6, 7: Rotating shaft 8: Polishing pad 9: Polishing area 10: Light transmission area 11: Transparent support film 12: Through hole 13: Shelf part 14: Opening part 15: Resin sheet 16: Groove 17: Shoulder part 18: Head Part 19: Cutting position 20: Adhesive layer (double-sided tape)
21: Cushion layer

Claims (6)

  1. A step of producing a polishing region made of polyurethane foam, a step of forming an opening made of a through hole and a shelf in the polishing region, a step of producing a convex light transmission region thinner than the polishing region, and the light transmission A method for producing a polishing pad, comprising: a step of placing a region in an opening of the polishing region; and a step of bonding a transparent support film to the polishing back surface side of the polishing region.
  2. The method for manufacturing a polishing pad according to claim 1, wherein the thickness of the thickest portion of the light transmission region is 50 to 90% of the thickness of the polishing region.
  3. The method for manufacturing a polishing pad according to claim 1, wherein the light transmission region is made of a thermosetting resin.
  4. The method for manufacturing a polishing pad according to claim 3, wherein the thermosetting resin is a polyurethane resin.
  5. The polishing pad manufactured by the method in any one of Claims 1-4.
  6. 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 5.
JP2006087985A 2006-03-28 2006-03-28 Method of manufacturing polishing pad Withdrawn JP2007260827A (en)

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008047631A1 (en) * 2006-10-18 2008-04-24 Toyo Tire & Rubber Co., Ltd. Method for producing long polishing pad
JP2008101089A (en) * 2006-10-18 2008-05-01 Toyo Tire & Rubber Co Ltd Manufacturing method for lengthy polishing pad
KR20120026506A (en) * 2009-04-23 2012-03-19 어플라이드 머티어리얼스, 인코포레이티드 Treatment of polishing pad window
JP2014050959A (en) * 2010-01-13 2014-03-20 Nexplanar Corp Cmp pad with local area transparency
JP2014172170A (en) * 2013-03-07 2014-09-22 Rohm & Haas Electronic Materials Cmp Holdings Inc Multilayer chemical mechanical polishing pad with broad-spectrum endpoint detection window
JP2014172169A (en) * 2013-03-07 2014-09-22 Rohm & Haas Electronic Materials Cmp Holdings Inc Multilayer chemical mechanical polishing pad
JP2014233834A (en) * 2013-05-31 2014-12-15 ローム アンド ハース エレクトロニック マテリアルズ シーエムピー ホウルディングス インコーポレイテッド Chemical mechanical window abrasive pad which is soft and capable of being conditioned
JP2016512926A (en) * 2013-03-15 2016-05-09 アプライド マテリアルズ インコーポレイテッドApplied Materials,Incorporated Polishing pad with auxiliary window seal

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008047631A1 (en) * 2006-10-18 2008-04-24 Toyo Tire & Rubber Co., Ltd. Method for producing long polishing pad
JP2008101089A (en) * 2006-10-18 2008-05-01 Toyo Tire & Rubber Co Ltd Manufacturing method for lengthy polishing pad
KR20120026506A (en) * 2009-04-23 2012-03-19 어플라이드 머티어리얼스, 인코포레이티드 Treatment of polishing pad window
JP2012524672A (en) * 2009-04-23 2012-10-18 アプライド マテリアルズ インコーポレイテッドApplied Materials,Incorporated Polishing pad window processing
KR101587821B1 (en) 2009-04-23 2016-01-22 어플라이드 머티어리얼스, 인코포레이티드 Treatment of polishing pad window
JP2014050959A (en) * 2010-01-13 2014-03-20 Nexplanar Corp Cmp pad with local area transparency
JP2015096293A (en) * 2010-01-13 2015-05-21 ネクスプラナー コーポレイション Cmp pad with local area transparency
JP2014172169A (en) * 2013-03-07 2014-09-22 Rohm & Haas Electronic Materials Cmp Holdings Inc Multilayer chemical mechanical polishing pad
JP2014172170A (en) * 2013-03-07 2014-09-22 Rohm & Haas Electronic Materials Cmp Holdings Inc Multilayer chemical mechanical polishing pad with broad-spectrum endpoint detection window
TWI628041B (en) * 2013-03-07 2018-07-01 羅門哈斯電子材料Cmp控股公司 A multilayer chemical mechanical polishing pad with broad spectrum, endpoint detection window
JP2016512926A (en) * 2013-03-15 2016-05-09 アプライド マテリアルズ インコーポレイテッドApplied Materials,Incorporated Polishing pad with auxiliary window seal
JP2018026588A (en) * 2013-03-15 2018-02-15 アプライド マテリアルズ インコーポレイテッドApplied Materials,Incorporated Polishing pad with secondary window seal
JP2014233834A (en) * 2013-05-31 2014-12-15 ローム アンド ハース エレクトロニック マテリアルズ シーエムピー ホウルディングス インコーポレイテッド Chemical mechanical window abrasive pad which is soft and capable of being conditioned

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