TW201620027A - Grinding pad - Google Patents

Abstract

The purpose of the present invention is to provide a grinding pad that, although being structured such that the back surface of a window is adhered to an adhesive member, is capable of performing high-accuracy optical final point sensing. The grinding pad comprises a grinding layer including a grinding region and a light transmitting region, and a support layer including an opening portion, the layers being laminated via an adhesive member with the light transmitting region and the opening portion overlapping each other, and is characterized in that the back surface of the adhesive member in the opening portion has an arithmetic mean roughness Ra of not more than 1 [mu]m.

Description

Abrasive pad

The present invention relates to a polishing pad used for planarizing a surface of a workpiece such as a semiconductor wafer by chemical mechanical polishing (CMP), and more particularly to a method for detecting by optical means. A polishing pad for a window (light transmission region) such as a polishing condition, and a method for manufacturing a semiconductor device using the polishing pad.

When manufacturing a semiconductor device, a step of forming a conductive film on a surface of a semiconductor wafer (hereinafter referred to as a wafer), forming a wiring layer by photolithography, etching, or the like, and a step of forming an interlayer insulating film on the wiring layer are performed. The steps cause the surface of the wafer to have irregularities including conductors or insulators such as metal. In recent years, in order to increase the density of semiconductor integrated circuits and to make wiring finer and multilayer wiring, it is important to flatten the unevenness on the surface of the wafer.

As a method of flattening the unevenness of the surface of the wafer, a CMP method is generally employed. CMP is a technique in which a slurry-like abrasive (hereinafter referred to as a slurry) in which abrasive grains are dispersed is used for polishing while the surface to be polished of the wafer is pressed against the polishing surface of the polishing pad.

There is a problem in determining the flatness of the wafer surface when such CMP is performed. That is, it is necessary to detect the point in time at which the desired surface characteristic or planar state is reached. Conventionally, the test wafer is periodically processed about the film thickness and the polishing rate of the oxide film, and after confirming the result, the wafer to be processed is polished.

However, in this method, the time and cost of processing the test wafer are wasted, and the test wafer and the product wafer which are not completely processed in advance may have different grinding results due to the CMP-specific load effect, if the product crystal is not actually processed. It is difficult to accurately predict the processing results.

Therefore, recently, in order to eliminate the above problems, it is desirable to have a method in which the time characteristics of the obtained surface characteristics and thickness can be detected in the field during the CMP process. There are various methods for such detection, and optical detection means become the mainstream in terms of measurement accuracy or spatial resolution of non-contact measurement.

The optical detecting means is a method of specifically irradiating a light beam through a window (light transmitting region) through a polishing pad to irradiate the wafer, and monitoring an interference signal generated by the reflection thereof, thereby detecting the polishing end point.

Various polishing pads have been proposed for the polishing pad used in the end point detection method of polishing by such optical means. In the future, regarding the high integration and miniaturization of semiconductor manufacturing, it is expected that the wiring width of the integrated circuit will become smaller and smaller, so it is required to perform the polishing of the optical end point detection with high precision. pad.

For example, Patent Document 1 proposes a polishing pad for performing chemical mechanical planarization of a semiconductor substrate, comprising: a polishing pad body having an opening formed at a center; and a window for performing a substrate on the substrate Optically measured and fixed in the aforementioned opening portion; the window has a surface below which light can be incident, and the lower surface is subjected to a laser ablation treatment to remove surface roughness present on the lower surface.

Further, Patent Document 2 proposes a chemical mechanical polishing pad which is provided with a non-polishing surface having a polishing surface opposite to the polishing surface, and has a light-transmitting region that optically passes from the polishing surface to the non-polishing surface. The surface roughness (Ra) of the non-polishing surface of the light-transmitting region is 10 μm or less, and the transmittance of the light-transmitting region for light having a wavelength of 633 nm is 12% to 70%.

Further, Patent Document 3 proposes a chemical mechanical polishing pad having a non-polishing surface having a polishing surface opposite to the polishing surface, and having a light-transmitting region that optically passes from the polishing surface to the non-polishing surface, The surface roughness (Ra) of the non-polishing surface in the optical region is smaller than the surface roughness (Ra) of the polishing surface.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2007-049163

Patent Document 2: Japanese Patent Laid-Open Publication No. 2008-073845

Patent Document 3: Japanese Patent Laid-Open Publication No. 2008-226911

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing pad which has a structure in which a back surface of a window is followed by a member, but optical end point detection can be performed with high precision.

The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above object can be attained by the polishing pad described below, and the present invention has been completed.

In other words, the polishing pad according to the present invention is characterized in that the polishing layer having the polishing region and the light-transmitting region and the support layer having the opening portion are formed by laminating the light-transmitting region and the opening portion via the bonding member, and the foregoing The arithmetic mean roughness Ra of the back surface of the above-mentioned member in the opening portion is 1 μm or less.

The adhesive member is preferably an adhesive layer or a double-sided tape having an adhesive layer on both sides of the substrate.

In addition, the present invention relates to a polishing pad which is to polish a region and then The member, the support layer, and the double-sided adhesive sheet are sequentially laminated, and a light transmission region is provided in the opening portion of the polishing region, the adhesive member, and the support layer, and the double-sided adhesive sheet is disposed in the opening portion The arithmetic mean roughness Ra of the back surface of the double-sided succeeding film is 1 μm or less.

Compared with the polishing pad exposed on the back side of the light transmission region, the polishing pad having the back surface of the light transmission region and the structure of the subsequent member or the double-sided adhesive sheet has a problem that the optical end point detection accuracy is extremely low. The inventors believe that the reason is that the light beam is absorbed or light-scattered due to the adhesive member or the double-sided adhesive sheet provided on the back surface of the light-transmitting region before the light beam is incident on the light-transmitting region. Then, the inventors of the present invention conducted an intensive study and found that the light-scattering of the light beam is suppressed by setting the arithmetic mean roughness Ra of the back surface of the opening member or the back surface of the double-sided back sheet to 1 μm or less as described above. Optical endpoint detection is performed with high precision.

Further, the present invention relates to a method of manufacturing a semiconductor device comprising the step of polishing a surface of a semiconductor wafer using the polishing pad.

The polishing pad of the present invention has a structure in which the back surface of the light-transmitting region is not exposed and follows the subsequent member or the double-sided film, but the optical end point detection can be performed with high precision.

1‧‧‧ polishing pad

2‧‧‧grinding platen

3‧‧‧Abrasive agent (slurry)

4‧‧‧Weared material (semiconductor wafer)

5‧‧‧Support table (grinding head)

6, 7‧‧‧ rotating shaft

8‧‧‧Abrasion area

9‧‧‧Light transmission area

10, 13, 16‧ ‧ openings

11‧‧‧Next component

12‧‧‧Support layer

14‧‧‧The back member of the opening or the back of the double-sided film

15‧‧‧Double-sided film

Fig. 1 is a schematic block diagram showing an example of a polishing apparatus used for CMP polishing.

Fig. 2 is a schematic cross-sectional view showing an example of a polishing pad of the present invention.

Fig. 3 is a schematic cross-sectional view showing another example of the polishing pad of the present invention.

The polishing pad of the present invention has a structure in which a polishing layer having a polishing region and a light transmission region and a support layer having an opening portion are formed by laminating the light-transmitting region and the opening portion via a bonding member.

Another polishing pad of the present invention has a structure in which a polishing region, an adhesive member, a support layer, and a double-sided adhesive sheet are sequentially laminated, and are inserted into the polishing region, the subsequent member, and the opening portion of the support layer and are in the foregoing double A light transmission area is provided on the surface of the sheet.

The polishing region is not particularly limited as long as it is a foam having fine bubbles. For example, a polyurethane resin, a polyester resin, a polyamide resin, an acrylic resin, a polycarbonate resin, a halogen resin (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.) One or a mixture of two or more kinds of polystyrene, olefin resin (such as polyethylene or polypropylene), epoxy resin, and photosensitive resin. Since the polyurethane resin is excellent in abrasion resistance and can be variously changed in the composition of the raw material, and it is easy to obtain a polymer having desired physical properties, it is a material which is particularly preferable as a material for forming a polishing region. Hereinafter, the polyurethane is represented by the above-mentioned foam. fat.

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

As the isocyanate component, a compound known in the field of polyurethanes can be used without particular limitation. Examples of the isocyanate component include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-. Aromatic diisocyanate such as diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylene diisocyanate, m-xylene diisocyanate; ethyl diisocyanate, 2, 2 , an aliphatic diisocyanate such as 4-trimethylhexamethylene diisocyanate or 1,6-hexamethylene diisocyanate; 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate An alicyclic diisocyanate such as isophorone diisocyanate or norbornane diisocyanate. These may be used alone or in combination of two or more.

Examples of the high molecular weight polyol include those generally used in the technical field of polyurethanes. For example, a polyether polyol represented by polytetramethylene ether glycol or polyethylene glycol, a polyester polyol represented by polybutylene adipate, a polycaprolactone polyol, and a polycap. a polyester polycarbonate polyol exemplified by a reactant of a polyester diol such as a lactone and a alkylene carbonate, reacting an ethyl carbonate with a polyol, and reacting the obtained reaction mixture with an organic dicarboxylic acid. Polyester polycarbonate polyol, by polyvalent hydroxyl group A polycarbonate polyol obtained by transesterification of a compound with an aryl carbonate. These may be used alone or in combination of two or more.

As the polyol component, in addition to the above high molecular weight polyol, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 may be used in combination. -butanediol, 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, two Ethylene glycol, triethylene glycol, 1,4-bis(2-hydroxyethoxy)benzene, trimethylolpropane, glycerol, 1,2,6-hexanetriol, pentaerythritol, four Hydroxymethylcyclohexane, methyl glucoside, sorbitol, mannitol, galactitol, sucrose, 2,2,6,6-tetrakis(hydroxymethyl)cyclohexanol, diethanolamine, N-methyl Low molecular weight polyols such as diethanolamine and triethanolamine. Further, a low molecular weight polyamine such as ethylenediamine, toluenediamine, diphenylmethanediamine, or diethylenetriamine may be used in combination. Further, an alcoholamine such as monoethanolamine, 2-(2-aminoethylamino)ethanol or monopropanolamine may be used in combination. These low molecular weight polyols and low molecular weight polyamines may be used alone or in combination of two or more. The blending amount of the low molecular weight polyol or the low molecular weight polyamine or the like is not particularly limited, and can be appropriately determined depending on the properties required for the polishing pad to be produced.

When the polyurethane resin foam is produced by the prepolymer method, the prepolymer is cured by using a chain extender. The chain extender is an organic compound having at least two active hydrogen groups, and the active hydrogen group may, for example, be a hydroxyl group, a primary or secondary amine group, a thiol group (SH) or the like. Specific examples thereof include 4,4'-methylenebis(o-chloroaniline) (MOCA), 2,6-dichloro-p-phenylenediamine, 4,4'- Methylene bis(2,3-dichloroaniline), 3,5-bis(methylthio)-2,4-toluenediamine, 3,5-bis(methylthio)-2,6-toluene Amine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, trimethylene glycol-di-p-amino benzoate, Polyoxytetramethylene-di-p-aminobenzoic acid ester, 4,4'-diamino-3,3',5,5'-tetraethyldiphenylmethane, 4,4'-diamine -3,3'-diisopropyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3',5,5'-tetraisopropyldiphenylmethane 1,2-bis(2-aminophenylthio)ethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, N, N'-di-t-butyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, m-xylenediamine, N A polyamine exemplified as N'-di-t-butyl-p-phenylenediamine, m-phenylenediamine, and p-xylenediamine, or a low molecular weight polyhydric alcohol or a low molecular weight polyamine. 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 of them, the desired physical properties of the polishing pad, and the like. In order to obtain a polishing pad having desired polishing characteristics, the number of isocyanate groups of the isocyanate component is preferably from 0.80 to 1.20, more preferably from 0.99 to the total active hydrogen group (hydroxy + amine group) of the polyol component and the chain extender. 1.15. When the number of isocyanate groups is out of the above range, there is a tendency that a hardening failure occurs and the desired specific gravity and hardness are not obtained, and the polishing property is lowered.

Polyurethane resin foam can be applied by melt method, solution method, etc. It is preferably produced by a melting method in consideration of cost, working environment, etc., by a known urethanization technique.

The polyurethane resin foam can be produced by any one of a prepolymer method and a one shot method, but it is preferably because the obtained polyurethane resin is excellent in physical properties. A prepolymer method in which an isocyanate-based terminal prepolymer is synthesized from an isocyanate component and a polyol component, and then reacted with a chain extender.

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.

More preferably, it is a mechanical foaming method using a polyfluorene-based surfactant which is a copolymer of a polyalkyl siloxane and a polyether and does not have an active hydrogen group.

Further, stabilizers such as antioxidants, lubricants, pigments, fillers, antistatic agents, and other additives may be added as needed.

The polyurethane foam may be either a closed cell type or a continuous cell type.

The production of the polyurethane foam may be a batch method in which the components are charged into a container and stirred, and the components and the non-reactive gas may be continuously supplied to the stirring device, stirred, and sent out. bubble A continuous production method for producing a molded article from a dispersion.

Further, a method in which a prepolymer of a raw material of a polyurethane foam is added to a reaction container, and then a chain extender is added and stirred, and then poured into a mold of a specific size to form a lump, and The block is sliced using a planer or band saw-like microtome, or formed into a sheet shape at the stage of flowing into the mold. Further, the resin of the raw material may be melted and extruded from a T die to directly obtain a sheet-like polyurethane resin foam.

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

The specific gravity of the polyurethane foam is preferably from 0.5 to 1.3. When the specific gravity is less than 0.5, the surface strength of the polishing region is lowered, and the planarity of the material to be polished tends to decrease. On the other hand, when it is more than 1.3, the number of bubbles on the surface of the polishing region is small, and the planarity is good, but the polishing rate tends to decrease.

The hardness of the polyurethane foam is preferably from 40 to 75 degrees in terms of ASKER-D hardness. When the ASKER-D hardness is less than 40 degrees, the flatness of the material to be polished tends to decrease, and when it is greater than 75 degrees, Although the planarity is good, there is a tendency that the uniformity (homogeneity) of the material to be polished is lowered.

The abrasive surface of the abrasive region that is in contact with the material to be polished preferably has a textured structure for holding and renewing the slurry. The polishing region including the foam has a large number of openings on the polishing surface, and has the function of holding and renewing the slurry. By forming the uneven structure on the polishing surface, the slurry can be maintained and renewed more efficiently, and can be prevented. Destruction of the material to be polished caused by adsorption with the material to be polished. The uneven structure is not particularly limited as long as it retains and renews the shape of the slurry, and examples thereof include an XY lattice groove, a concentric circular groove, an opening, a non-through hole, a polygonal column, a cylinder, a spiral groove, and an eccentric circular groove. , radial grooves, and the combination of these grooves. Further, the uneven structures are generally regular, but the groove pitch, the groove width, the groove depth, and the like may be changed in a certain range in order to maintain and renew the slurry.

The shape of the polishing region is not particularly limited, and may be a circular shape or a long strip shape. The size of the polishing zone can be appropriately adjusted according to the polishing apparatus to be used. When the shape is round, the diameter is about 30 cm to 150 cm, and in the case of a long strip, the length is about 5 m to 15 m, and the width is about 60 cm to 250 cm.

The thickness of the polishing region is not particularly limited, but is usually about 0.8 mm to 4 mm, preferably 1.2 mm to 2.5 mm.

The material for forming the light-transmitting region is not particularly limited, and it is preferable to use a material which can perform optical end point detection with high precision in a polished state and has a light transmittance of 10% or more over the entire wavelength range of 400 nm to 700 nm. A material having a light transmittance of 20% or more is more preferably a material having a light transmittance of 50% or more. Examples of such a material include a thermosetting resin such as a polyurethane resin, a polyester resin, a phenol resin, a urea resin, a melamine resin, an epoxy resin, and an acrylic resin; and a polyurethane Resin, polyester resin, polyamide resin, cellulose resin, acrylic resin, polycarbonate resin, halogen resin (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, And a thermoplastic resin such as an olefin resin (such as polyethylene or polypropylene); a rubber such as butadiene rubber or isoprene rubber; a photocurable resin which is cured by light such as ultraviolet rays or electron beams, and a photosensitive resin. These resins may be used singly or in combination of two or more.

The material for the light-transmitting region is preferably of the same or larger grinding property as the material used for the polishing region. The so-called grinding property refers to the degree of grinding by the material to be polished or the dresser during the grinding. As described above, the light-transmitting region does not protrude from the polishing region, and the scratching of the material to be polished or the nip failure in the grinding can be prevented.

Further, it is preferred to use a forming material for the polishing region or a material similar to the physical properties of the polishing region. More preferably, it is a highly abrasion-resistant polyurethane which suppresses light scattering in a light-transmitting region caused by trimming marks in polishing. Resin.

The shape and size of the light transmission region are not particularly limited, but are preferably the same shape and size as the opening portion of the polishing region.

The ASKER-D hardness of the light transmission region is preferably from 30 degrees to 75 degrees. By using the light transmission region of the hardness, it is possible to suppress scratches on the surface of the wafer and deformation of the light transmission region. In addition, it is possible to suppress the occurrence of scratches on the surface of the light-transmitting region, thereby stably performing highly accurate optical end point detection. The ASKER-D hardness of the light transmission region is preferably from 40 to 75 degrees.

The support layer complements the characteristics of the abrasive zone. As the support layer, a layer having a lower modulus of elasticity than the polishing region (buffer layer) may be used, or a layer having a higher modulus of elasticity than the region to be polished (highly elastic layer) may be used. The buffer layer is necessary for both planarity and uniformity of the compromise relationship in CMP. The term "planarity" refers to the flatness of the pattern portion when the material to be polished having fine irregularities generated during pattern formation is polished, and the uniformity refers to the uniformity of the entire material to be polished. The properties of the abrasive region are utilized to improve planarity, and the characteristics of the buffer layer are utilized to improve uniformity. When a soft abrasive region is used in order to suppress scratch generation in CMP, a high elastic layer is used to enhance the planarization characteristics of the polishing pad. Moreover, by using a highly elastic layer, excessive grinding of the edge portion of the material to be polished can be suppressed.

Examples of the buffer layer include polyester non-woven fabric, nylon non-woven fabric, and acrylic Non-woven fabric such as olefin-based non-woven fabric; impregnated resin-impregnated fabric such as polyester non-woven fabric impregnated with polyurethane; polyester resin foam such as polyurethane foam and polyethylene foam; butadiene rubber And a rubber resin such as isoprene rubber; a photosensitive resin.

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

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

The high elastic layer is preferably a resin film which has a dimensional change ratio of 1.2% or less after heating at 150 ° C for 30 minutes and before heating. More preferably, the resin film having a dimensional change ratio of 0.8% or less is preferably a resin film having a dimensional change ratio of 0.4% or less. Examples of the resin film having such characteristics include a polyethylene terephthalate film subjected to heat shrinkage treatment, a polyethylene naphthalate film, and a polyimide film.

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

Fig. 2 is a schematic cross-sectional view showing an example of a polishing pad of the present invention. The polishing region 8 is provided with a light transmission region 9 for performing optical end point detection in a polished state. The light transmission region 9 is embedded in the opening portion 10 provided in the polishing region 8, and is fixed by the subsequent member 11 following the polishing region 8. The support layer 12 has an opening portion 13 for transmitting light. The opening 13 may be the same size as the opening 10, or may be smaller than the opening 10 or larger than the opening 10.

Next, the member 11 is preferably a double-sided tape in which an adhesive layer containing a pressure-sensitive adhesive or a hot-melt adhesive is used, or the above-mentioned adhesive layer is provided on both surfaces of the substrate. The double-sided tape is preferred because it can prevent the slurry from penetrating toward the support layer side by the substrate, and can effectively prevent peeling between the support layer and the adhesive layer.

Examples of the substrate include a resin film and the like. Examples of the resin film include polyester films such as polyethylene terephthalate film and polyethylene naphthalate film; polyolefin films such as polyethylene film and polypropylene film; and nylon. Membrane; polyimine film and the like. Among these, it is preferred to use a polyester film which is excellent in water permeability prevention property.

The surface of the substrate may be subjected to easy treatment such as corona treatment or plasma treatment.

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

The thickness of the subsequent layer is preferably from 10 μm to 300 μm, more preferably from 25 μm to 200 μm.

The arithmetic mean roughness Ra of the back surface 14 of the adhesive member 11 in the opening portion 13 is 1 μm or less, preferably 0.5 μm or less, more preferably 0.3 μm or less, and still more preferably 0.2 μm or less.

The method of setting the arithmetic mean roughness Ra to 1 μm or less is not particularly limited, and examples thereof include the following methods.

The surface of the adhesive layer or double-sided tape is usually provided with a release film for protecting the adhesive surface, which is peeled off during use. The arithmetic mean roughness Ra of the surface of the general release film is about 2 μm to 3 μm, and the arithmetic mean roughness Ra of the surface of the adhesive layer adhered to the release film is also about 2 μm to 3 μm. As the release film, by using the arithmetic mean roughness Ra of the surface of 1 μm or less, the surface roughness can be transferred to the surface of the adhesive layer, and the arithmetic mean thickness of the surface of the adhesive layer or the double-sided tape can be made coarse. The degree Ra is 1 μm or less.

Examples of the release film having an arithmetic mean roughness Ra of the surface of 1 μm or less include a polyester film such as a polyethylene terephthalate film or a polyethylene naphthalate film; a polyethylene film and a polypropylene film; Polyolefin film; nylon film; Polyimine film and the like.

Fig. 3 is a schematic cross-sectional view showing another example of the polishing pad of the present invention. The polishing pad 1 is formed by sequentially laminating the polishing layer 8, the subsequent member 11, the support layer 12, and the double-sided adhesive sheet 15, and is inserted into the opening portion 16 of the polishing layer 8, the subsequent member 11, and the support layer 12. A light transmission region 9 is provided on the double-sided adhesive sheet 15.

The double-sided adhesive sheet 15 has an adhesive layer on both sides of the substrate, and the above-mentioned double-sided tape can be used. The double-sided adhesive sheet 15 is used to attach the polishing pad 1 to the polishing platen 2.

The polishing pad 1 can be manufactured, for example, by the following method. First, the polishing layer 8 and the support layer 12 are laminated via the bonding member 11 to form a laminated sheet. The opening portion 16 is formed in the produced laminated sheet. The double-sided back sheet 15 is attached to the support layer 12 on which the laminated sheet having the opening portion 16 is formed. Then, a light transmission region 9 is provided in the opening portion 16 on the double-sided adhesive sheet 15. Further, after the light transmission region 9 is inserted into the opening portion 16, the double-sided adhesive sheet 15 may be attached to the support layer 12 and the light transmission region 9.

The arithmetic mean roughness Ra of the back surface 14 of the double-sided adhesive sheet 15 in the opening portion 16 is 1 μm or less, preferably 0.5 μm or less, more preferably 0.3 μm or less, and still more preferably 0.2 μm or less.

The method of setting the arithmetic mean roughness Ra to 1 μm or less is not particularly limited, and examples thereof include the same methods as described above.

The surface height of the light transmission region 9 is preferably the same height as the surface height of the polishing region 8, or is lower than the surface height of the polishing region 8. When the surface height of the light-transmitting region 9 is higher than the surface height of the polishing region 8, there is a flaw in the portion to be polished due to the protruding portion during the polishing. Further, the light-transmitting region 9 is deformed by the stress applied during polishing, and the optical property is largely changed. Therefore, the accuracy of the optical end point detection of the polishing is lowered.

The semiconductor element is manufactured by the step of polishing the surface of the semiconductor wafer using the polishing pad. A semiconductor wafer is usually laminated with a wiring metal and an oxide film on a germanium wafer. The polishing method and the polishing apparatus for the semiconductor wafer are not particularly limited, and are performed, for example, by using a polishing apparatus as shown in FIG. 1. The polishing platen 2 is provided to support the polishing pad 1 and the support table (the polishing head) 5) supporting the semiconductor wafer 4; the mat is used for uniformly pressurizing the wafer; and the supply mechanism of the abrasive 3. The polishing pad 1 is attached to the polishing platen 2, for example, by being attached by a double-sided tape. The polishing platen 2 and the support table 5 are disposed such that the polishing pad 1 supported by the polishing pad 2 and the semiconductor wafer 4 face each other, and each of the rotating shafts 6 and 7 is provided. Further, a pressurizing mechanism for pressing the semiconductor wafer 4 against the polishing pad 1 is provided on the support table 5 side. At the time of polishing, the semiconductor wafer 4 is pressed against the polishing pad 1 while the polishing platen 2 and the support table 5 are rotated, and the slurry is supplied while being polished. Slurry flow rate, grinding load, grinding platen speed, The wafer rotation speed is not particularly limited and is appropriately adjusted.

Thereby, the protruding portion of the surface of the semiconductor wafer 4 is removed and ground into a flat shape. Thereafter, the semiconductor element is fabricated by performing dicing, bonding, packaging, or the like. The semiconductor element is used for an arithmetic processing device, a memory, or the like.

[Examples]

The invention is illustrated by the following examples, but the invention is not limited to the examples.

[Measurement, evaluation method]

(Measurement of arithmetic mean roughness)

A sample was obtained by cutting the laminated portion of the light-transmitting region and the adhesive layer in the opening from the produced polishing pad. The arithmetic mean roughness Ra (μm) of the surface of the adhesive layer of the sample was measured in accordance with JIS B0601-1994.

(evaluation of endpoint detection)

Using MIRRA (manufactured by AMAT Co., Ltd.) as a polishing apparatus, and using the produced multilayer polishing pad, a wafer having a tungsten film of 10000 Å formed on a 8 Å wafer was subjected to wafer polishing for 60 seconds, and optical end point detection was examined.

○: End point detection is available

×: End point detection is not possible

Example 1

[production of light transmission area]

100 parts by weight of a polyether-based prepolymer (manufactured by Uniroyal Co., Ltd., Adiprene L-325, NCO concentration: 2.22 meq/g) was previously adjusted to 70 ° C, and 4,4'-Asia adjusted to a temperature of 120 ° C was added thereto. Methyl bis(o-chloroaniline) (Iharacuamine MT, manufactured by Ihara Chemical Co., Ltd.) was 26 parts by weight and stirred for about 1 minute. Then, the mixed solution was poured into a mold kept at 100 ° C, and post-cured at 100 ° C for 8 hours to prepare a polyurethane resin. The produced polyurethane resin was cut with a Thomson knife of a specific size to prepare a light transmission region (55.8 mm × 19.8 mm, thickness 1.95 mm).

[Production of abrasive layer with double-sided tape]

In a reaction container, a polyether-based prepolymer (manufactured by Uniroyal Co., Ltd., Adiprene L-325, NCO concentration: 2.22 meq/g) was used in an amount of 100 parts by weight, and a polyfluorene-based surfactant (Toray Dow Corning Silicone Co., Ltd., SH-192) 3 parts by weight were mixed and the temperature was adjusted to 80 °C. Stirring was carried out for about 4 minutes by using a stirring blade at a rotation speed of 900 rpm so as to incorporate bubbles into the reaction system. 4,4'-methylenebis(o-chloroaniline) (Iharacuamine MT-N, manufactured by Ihara Chemical Co., Ltd.) which was previously melted at 120 ° C was added thereto in an amount of 26 parts by weight. Then, after stirring was continued for about 1 minute, the reaction solution was poured into an open mold of a pan type. The time point at which the fluidity of the reaction solution disappeared was placed in an oven, and the mixture was hardened at 110 ° C for 6 hours to obtain a polyurethane foam block. Using a band saw The polyurethane foam block was sliced by a microtome (manufactured by Fecken Co., Ltd.) to obtain a polyurethane foam sheet. Then, the surface of the sheet was polished to a specific thickness using a polishing machine (manufactured by Amitec Co., Ltd.) to prepare a sheet having an adjusted thickness precision (sheet thickness: 2.00 mm). The polished sheet was punched out to a specific diameter (76 cm), and a groove having a groove width of 0.40 mm, a groove pitch of 3.10 mm, and a groove depth of 0.76 mm was formed using a groove processing machine (manufactured by Toho Steel Co., Ltd.). Groove processing. Thereafter, an opening (56 mm × 20 mm) for inserting the light-transmitting region was formed at a specific position of the sheet processed in the groove to form a polishing region. Then, on the opposite side of the polishing area from the groove processing surface, a laminator is used to have an adhesive layer on both sides of the substrate, and the surface of the adhesive layer is made of a release film (attached to the adhesive layer) The double-sided tape (thickness: 0.15 mm) of the surface of the double-sided tape (thickness: 0.15 mm) of the surface is bonded while the release film is peeled off, and the light-transmitting region is further embedded in the opening of the polishing region. The double-sided tape is attached to the above, and an abrasive layer with double-sided tape is produced.

[Production of polishing pad]

Using a laminator, a buffer layer composed of a polished and corona-treated polyethylene foam (Toraype, Toraypef, thickness: 0.8 mm) was attached to the produced abrasive layer with double-sided tape. The agent layer is used to make an abrasive sheet. Next, the double-sided adhesive sheet was attached to the buffer layer of the polishing sheet to obtain a laminate. After that, only the buffer layer of the laminate and the double-sided sheet are formed into openings of a size of 60 mm × 20 mm. 2 structure of the polishing pad.

Example 2

[Production of the grinding area with double-sided tape]

A polishing region was produced in the same manner as in Example 1. Thereafter, using a laminating machine, a double-sided tape was attached to the surface of the polishing region opposite to the groove-finished surface, and a polishing region with a double-sided tape was produced.

[Production of polishing pad]

Using a laminator, a buffer layer composed of a polished and corona-treated polyethylene foam (Toraype, Toraypef, thickness: 0.8 mm) was attached to the prepared polishing region with double-sided tape. The agent layer is used to make an abrasive sheet. Next, an opening portion having a size of 60 mm × 20 mm was formed on the polishing sheet. Thereafter, a double-sided adhesive sheet having an adhesive layer on both sides of the substrate and the surface of the above-mentioned adhesive layer is protected by a release film (arithmetic average roughness Ra of the surface in contact with the adhesive layer: 0.17 μm) A material: polyethylene terephthalate (having a thickness of 25 μm), and a release film was peeled off while being applied to a buffer layer of the polishing sheet using a laminator to obtain a laminate. Then, the light-transmitting region produced in Example 1 was fitted into the opening of the laminated body and bonded to the double-sided succeeding film to produce a polishing pad having the structure of FIG.

Comparative example 1

In the production of the polishing layer with double-sided tape of Example 1, use A double-sided tape (substrate: poly pair) having an adhesive layer on both sides of the substrate and the surface of the above-mentioned adhesive layer is protected by a release film (arithmetic average roughness Ra of the surface in contact with the adhesive layer: 1.5 μm) A polishing pad having the structure of Fig. 2 was produced in the same manner as in Example 1 except that ethylene phthalate (25 μm thick) was used.

[Industrial availability]

The polishing pad of the present invention is used for planarization processing of materials requiring high surface flatness such as optical materials such as lenses and mirrors, glass substrates for hard disks, glass substrates for hard disks, aluminum substrates, and general metal polishing processes. The polishing pad of the present invention is particularly suitable for use in a planarization step prior to further laminating a germanium wafer and an element having an oxide layer, a metal layer or the like formed thereon to form the oxide layer or the metal layer.

1‧‧‧ polishing pad

8‧‧‧Abrasion area

9‧‧‧Light transmission area

10, 13‧‧‧ openings

11‧‧‧Next component

12‧‧‧Support layer

14‧‧‧The back member of the opening or the back of the double-sided film

15‧‧‧Double-sided film

Claims (4)

A polishing pad obtained by laminating a polishing layer having a polishing region and a light transmission region and a support layer having an opening portion so as to overlap the opening portion by the light transmission region, and the aforementioned opening portion Next, the arithmetic mean roughness Ra of the back surface of the member is 1 μm or less. The polishing pad according to claim 1, wherein the adhesive member is an adhesive layer or a double-sided tape having an adhesive layer on both surfaces of the substrate. A polishing pad for sequentially laminating a polishing region, an adhesive member, a support layer, and a double-sided adhesive sheet, and providing light transmission through the polishing region, the subsequent member, and the opening portion of the support layer and on the double-sided adhesive sheet In the region, the arithmetic mean roughness Ra of the back surface of the double-sided back sheet in the opening portion is 1 μm or less. A method of manufacturing a semiconductor device, comprising the step of polishing a surface of a semiconductor wafer using the polishing pad according to any one of claims 1 to 3.