TW201946725A - Polishing pad and polishing method using the polishing pad - Google Patents

Abstract

The present invention is related to a polishing pad provided with an adsorption layer made of a predetermined silicone composition, which is hard to fall away from a surface plate during a polishing operation. More specifically, it is a polishing pad composed of a substrate, an adsorption layer formed on the substrate, and a polishing layer. The adsorption layer is made of a composition obtained by crosslinking at least one silicone selected from a silicone containing a linear polyorganosiloxane having a vinyl group only at both ends and the likes. The polishing pad is characterized by a ring-shaped shield member provided on the adsorption layer along an outer periphery of the polishing pad. The polishing pad is used with a polishing slurry being supplied onto a polishing layer in a state where the adsorption material is adsorbed and fixed to a surface plate during a polishing operation. The ring-shaped shield member suppresses the polishing slurry from penetrating into an interface between the adsorption layer and the surface plate.

Description

   Polishing pad and polishing method using the same   

The present invention relates to a polishing pad used in a polishing step of a member to be polished used in semiconductor parts, electronic parts, and the like. In particular, the present invention relates to a polishing pad that can efficiently perform a replacement operation of a polishing pad during polishing processing of a member to be polished such as a semiconductor wafer, and can prevent the polishing pad from shifting and peeling during the polishing operation.

The manufacturing process of semiconductor components such as semiconductor wafers, glass substrates for displays, and substrates for hard disks and electronic components includes a polishing step for flattening or mirror-finishing the surface of a substrate or the like. The polishing step is performed by fixing a polishing pad to a platform of a polishing apparatus, and while supplying a polishing slurry to the surface of the polishing layer of the polishing pad, sliding the member to be polished and the polishing pad under a pressurized state.

As for a method of fixing the polishing pad to the platform, a method using an adhesive material such as an adhesive tape has been the mainstream in the past. However, in this fixing method, the procedures for replacing and fixing the polishing pad are complicated, and the working efficiency of the polishing step is greatly reduced. Regarding the problem of fixing the polishing pad, there has been developed a polishing pad that can be easily fixed and replaced (Patent Documents 1 and 2).

    [Prior technical literature]         [Patent Literature]    

[Patent Document 1] Japanese Utility Model Registration No. 3166396

[Patent Document 2] Japanese Patent No. 5765858

The external appearance of this polishing pad provided with an adsorption layer is shown in FIG. 6. This polishing pad is provided with an adsorption layer made of a predetermined silicone compound having an adsorption function on the back surface side of a substrate supporting the polishing layer. The polysiloxane compound constituting the adsorption layer has an adsorption effect on materials such as glass or metal, and has a good holding force. Regarding the holding force due to the adsorption, a characteristic was observed in which the shear force (fixed strength in the horizontal direction) was high but the peeling force (fixed strength in the vertical direction) was low. This feature is suitable for fixing the polishing pad to the platform. This is because the polishing pad continuously receives horizontal stress during the polishing operation, and therefore requires a high holding force in terms of shear force. Regarding the holding force in the vertical direction, since the polishing pad is pressed against the platform, a large holding force is not necessarily required. In addition, the adsorption effect of the adsorption layer composed of the polysiloxane compound is uniform in the surface of the polishing pad, and it can exert an equal holding force from the center portion to the end portion. Therefore, a stable polishing operation can be expected.

In addition, the polishing pad has the advantages that it can be smoothly fixed to the platform and can be efficiently replaced. As described above, the adsorption layer of the polishing pad has a lower peeling force than the shear force. Therefore, as long as the polishing pad is gently pressed against the platform in the vertical direction, it can be fixed, and it can be easily mounted and dismounted. Therefore, the polishing pad proposed by the applicant of this case is also useful from the viewpoint of improving the efficiency of the polishing operation.

As mentioned above, the polishing pad provided by the applicant of the present case with a predetermined adsorption layer has good convenience in replacement and excellent fixing ability to the platform. However, according to the research by the inventors of the present application, it is confirmed that even when such a useful polishing pad is used, the polishing pad may be shifted or partially peeled off due to the polishing operation although it is rare. The deviation and peeling of the polishing pad are not necessarily caused by the deterioration of the adsorption layer due to the length of the polishing time or the frequency of replacement of the polishing pad. In addition, it is not a frequently occurring defect, and polishing operations can be performed without problems in almost all polishing environments and conditions. However, in order to make the polishing pad more popular, even if there is only a slight possibility, the troubles such as peeling should be ruled out.

The present invention has been made in view of the above-mentioned background, and is directed to a polishing pad having an adsorption layer composed of a predetermined polysiloxane composition, and provides a polishing pad capable of suppressing the occurrence of peeling from a platform and the like. The polishing method using the polishing pad is also disclosed.

In order to achieve the above-mentioned object, the inventors of the present invention have studied the cause of peeling from the platen and the like during a polishing operation with respect to a polishing pad having a predetermined adsorption layer. As a result, it was found that the polishing slurry sometimes penetrated into the interface between the adsorption layer of the polishing pad and the platen, which may cause peeling and the like. The polishing slurry is a suspension composed of "a dispersion of abrasive particles containing colloidal silica, alumina, cerium oxide, diamond, etc. in a solvent" as a basic structure. As a result of studies conducted by the inventors of the present case, it was found that the invasiveness of the polishing slurry to the interface between the polishing pad and the platform may increase depending on the composition and composition of the polishing slurry. In particular, it has been found that a polishing slurry having a low viscosity after adjusting the composition has high invasiveness to an interface.

The low-viscosity abrasive slurry is more easily penetrated into the interface due to the capillary effect caused by the fine gap between the polishing pad and the platform. In addition, the state where the slurry is accumulated at the interface is in a poor state for an adsorption layer composed of a polysiloxane composition, which causes a decrease in the adsorption force. Because the adsorption force is reduced, the polishing pad is peeled off or shifted from the platform.

However, even if the main reason for the decrease in the capacity of the adsorption layer of the polishing pad is the polishing slurry, it is difficult to easily change its composition and structure. The components and structure of the abrasive grains and the solvent constituting the polishing slurry are generally optimized according to the material of the member to be polished, the required polishing accuracy, and the like. Even if the polishing slurry may affect a specific polishing pad, it is not easy to allow the implementation of changes that affect polishing accuracy and the like.

Then, the inventors of the present invention solved the problems such as peeling from the platform by improving the structure of the polishing pad. Specifically, in order to prevent the polishing slurry from entering the interface between the adsorption layer and the platform of the polishing pad, a shielding member is disposed on the surface of the adsorption layer which is the back surface of the polishing pad.

That is, the present invention is a polishing pad, which is composed of a substrate, an adsorption layer formed on one surface of the substrate, and a polishing layer formed on the other surface of the substrate; wherein the polishing pad is formed during polishing During operation, the adsorption layer is adsorbed, fixed on the platform, and the grinding slurry is supplied to the grinding layer, and the user; the adsorption layer includes a composition composed of at least one polysilicone selected from the following polysilicones Product: Polysiloxane containing a linear polyorganosiloxane having a vinyl group only at both ends, polysiloxane containing a linear polyorganosiloxane having a vinyl group at both ends and side chains, containing polysiloxane A polysiloxane containing a branched polyorganosiloxane having a vinyl group at a terminal end, and a polysiloxane containing a branched polyorganosiloxane having a vinyl group at a terminal and side chain; The interface between the adsorption layer and the platform is provided with an annular shielding member along the outer periphery of the polishing pad on the adsorption layer.

The polishing pad of the present invention will be described in detail below. As described above, the present invention is basically the same as the conventional technology (Patent Documents 1 and 2), in which a base material is combined with a polishing layer and an adsorption layer formed on the front and back surfaces of the base material. In addition, it is characterized in that an annular shielding member is provided on the surface of the adsorption layer along the outer periphery of the polishing pad.

FIG. 1 is a view showing a specific example of a state in which the polishing pad provided with the ring-shaped shielding member of the present invention is fixed to a stage. As can be seen from Fig. 1, the diameter of the polishing pad of the present invention is set larger than the outer diameter of the table. In this polishing pad, a ring-shaped shielding member having a fixed width and thickness is bonded to the outer edge of the adsorption layer as the back surface. In addition, in this example, the inner diameter of the ring-shaped shielding member is substantially equal to the outer diameter of the platform.

In the polishing operation, the polishing pad is rotated while the polishing slurry is supplied onto the polishing layer. As shown in FIG. 2, the polishing slurry supplied to the surface of the polishing layer spreads and wets to the outer peripheral side at high speed due to centrifugal force, and reaches the side surface of the polishing pad. At this time, in the polishing pad of the present invention, the shielding member bonded to the adsorption layer blocks the polishing slurry and prevents the slurry from being caught on the back side of the polishing pad. Furthermore, since the polishing pad rotates at a high speed during the polishing operation, the blocked polishing slurry is scattered from the ring-shaped shielding member to the outside. This prevents the polishing slurry from intruding into the interface between the adsorption layer and the platform, and maintains the adhesion state of the adsorption layer.

As described above, the present invention is characterized in that the diameter of the polishing pad is slightly larger than that of the stage, and a ring-shaped shielding member is provided on the adsorption layer which becomes a wide portion. Hereinafter, the polishing pad of the present invention and a polishing method using the polishing pad will be described in more detail. First, each structure of a polishing pad is demonstrated.

(A) Composition of the polishing pad of the present invention

The polishing pad of the present invention is composed of a base material, a polishing layer, an adsorption layer, and a ring-shaped shielding member.

(A-1) Substrate

The substrate is a member for supporting the polishing layer and the adsorption layer, and is a member for ensuring the operability of the polishing pad. The substrate is a circular sheet-like member made of a thin organic substance. The substrate is preferably composed of a resin material having a breaking strength of 210 to 290 MPa and a breaking elongation of 80 to 130%. More preferably, the breaking strength is 210 to 240 MPa and the breaking elongation is 110 to 130%. The tensile strength is a value measured during drying.

The constituent materials of the substrate are specifically resins such as polyester, polyethylene, polystyrene, polypropylene, nylon, urethane, polyvinylidene chloride, and polyvinyl chloride. Polyester resin materials such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are preferred, and PET is particularly preferred. The substrate may be a single layer, or a multilayer structure may be formed from a plurality of resins.

The shape and size of the substrate, that is, the shape and size of the polishing pad can be round or square. As described above, the polishing pad of the present invention is adjusted in size so that the diameter is larger than the diameter of the table. As described later, specifically, it is preferable that it is 10 mm to 50 mm more than the diameter of the platform. The size of the platform can be selected according to the size of the material to be ground and the number of simultaneous grinding. In addition, the diameter (maximum diameter) of the polishing pad is often set in the range of 100 mm to 2000 mm.

(A-2) Polished layer

The polishing layer is a layer for polishing a member to be polished, as its name indicates. The polishing layer holds the supplied polishing slurry appropriately to polish the surface of the member to be polished. The polishing layer of the present invention can be applied to a polishing cloth conventionally used for a general polishing pad. For example, a non-woven fabric made of nylon, polyurethane, polyethylene terephthalate, etc., a foamed molded body, and the like can be applied. In addition, the shape of the surface (polishing surface) is not limited to a flat shape, and a groove or the like for holding an abrasive may be appropriately formed. The polishing cloth as the polishing layer preferably has a thickness of 0.5 to 3 mm.

The polishing layer is preferably firmly bonded to the substrate. The polishing layer and the substrate may be joined by a conventional method, and preferably, for example, is joined by an adhesive or an adhesive.

(A-3) Adsorption layer

An adsorption layer is a member which fixes a polishing pad to a platform by the adsorption | suction effect derived from the constituent material. As described above, the adsorption layer is composed of a polysiloxane composition, and is basically the same as that used in the conventional polishing pads (Patent Documents 1 and 2) proposed by the inventors of the present invention. That is, the polysiloxane composition constituting the adsorption layer is a composition composed of at least one polysiloxane selected from the following polysiloxanes: a linear polymer having a vinyl group only at both ends Polysiloxanes containing organosiloxanes, polysiloxanes containing linear polyorganosiloxanes having vinyl groups at both ends and side chains, polysiloxanes containing branched polyorganosiloxanes having vinyl groups only at the ends Siloxane, and polysiloxane containing branched polyorganosiloxanes having a vinyl group at the terminal and side chains.

Specific examples of the above-mentioned polysiloxane include a compound such as Chemical Formula 1 as an example of a linear polyorganosiloxane. In addition, a compound such as the compound 2 can be cited as an example of a branched polyorganosiloxane.

(In the formula, R represents the following organic group, and n represents an integer.)

(In the formula, R represents the following organic group, and m and n represent integers.)

Specific examples of the substituent (R) in Chemical Formula 1 and Chemical Formula 2 include alkyl groups such as methyl, ethyl, and propyl, aryl groups such as phenyl and tolyl, or carbon atoms of these groups. Some or all of the bonded hydrogen atoms are substituted with halogen atoms, cyano groups, and the like, or unsubstituted or substituted aliphatic unsaturated groups of the same or different type, and are monovalent hydrocarbon groups. Preferably, at least 50 mole% is methyl. The substituents may be different or the same. The polysiloxane may be used alone or as a mixture of two or more.

The polysiloxane that constitutes the adsorption layer has a proper adsorption effect if the number average molecular weight is 30,000 to 100,000. However, when adjusting the surface roughness, the number average molecular weight of the polysilicon used and the firing temperature of the manufacturing stage will affect. In order to easily exhibit an appropriate surface roughness, the number average molecular weight of the polysiloxane is preferably 30,000 to 60,000.

The thickness of the adsorption layer is preferably 20 to 50 μm. In addition, the thickness of the substrate is preferably 50 to 200 μm. The base material and the adsorption layer are preferably closely bonded.

The adsorption layer can be formed by applying a coating liquid containing the above-mentioned polysiloxane component onto a substrate and firing it. The cross-linking reaction of the polyorganosiloxane is performed by firing to form an adsorption layer in a state of being closely adhered to the substrate. The coating liquid used includes the above-mentioned linear and branched polyorganosiloxane compound and a crosslinking agent. The cross-linking agent may be a conventional one, and may be, for example, an organic hydrogenated polysiloxane. The organic hydrogenated polysiloxane has at least 3 hydrogen atoms bonded to silicon atoms in one molecule. Practically, it is preferable to set the number of molecules having two ≡SiH bonds in the molecule to 50 in total. Up to 3% by weight, and the remainder is set to include at least 3 SiH bonds in the molecule. The coating liquid may contain a platinum-based catalyst used in the crosslinking reaction. The coating liquid may be in any form of a solventless type, a solvent type, and an emulsion type. The firing after the coating liquid is applied is preferably heated at 120 to 180 ° C for 60 to 150 seconds.

(A-4) Ring-shaped shielding member

As described above, the polishing pad of the present invention is characterized by including an annular shielding member on the surface of the adsorption layer along the outer periphery of the polishing pad. The shielding member is used to block the polishing slurry supplied during the polishing operation to the outer peripheral portion of the polishing pad, so that the polishing slurry does not enter the interface between the adsorption layer and the platform.

The shield member has a ring shape having a fixed width and thickness. The cross-sectional shape in the vertical direction is basically rectangular (Figure 3 (a)), but it can also be chamfered on one or both sides of the lower end (Figures 3 (b) to (d) )). By performing the chamfering to form the inclination, the drainage of the polishing slurry from the shield member becomes favorable. The chamfer of the lower end portion of the shield member may be linearly inclined (tapered) (Figs. 3 (b) and (d)), or may be curved (curved) (Fig. 3 (c)). . In addition, the cross-sectional shape may be chamfered on one side end portion on the outer side or inner side (on the platform side), or may be chamfered on both end portions.

The width of the annular shield member is preferably 5 mm or more. This is because a certain degree of width is required in order to block the grinding slurry from reaching the platform. In addition, the inner diameter of the annular shielding member must be larger than the outer diameter of the platform. The polishing pad is designed so that the adsorption layer and the platform are in close contact with the user. Therefore, the width of the ring-shaped shielding member must be equal to or smaller than the difference between the radius of the polishing pad and the radius of the platform. As described later, the difference between the diameter of the polishing pad and the diameter of the stage is preferably set to 50 mm or less, so the width of the annular shield member is preferably set to 25 mm or less. In addition, the inner surface of the ring-shaped shielding member may be closely adhered to the side surface of the platform. In addition, a gap may be generated between the inner surface of the ring-shaped shielding member and the side surface of the platform instead of being tightly sealed.

The thickness (height) of the ring-shaped shielding member is preferably 10 mm to 50 mm. This is because an appropriate height is required to prevent the grinding slurry from reaching the platform.

Next, constituent materials of the ring-shaped shielding member will be described. The annular shielding member of the present invention is used to block the polishing slurry spread on the surface of the polishing surface so that it does not reach the platform on the back side of the polishing pad. Taking this function into consideration, a liquid-absorbent material can be used as the material of the shielding member. The absorption of the polishing slurry by the ring-shaped shielding member having water absorption may effectively prevent the polishing slurry from reaching the platform.

However, if the water absorption of the shielding member is too high, there is a concern that the slurry exuding from the shielding member in an excessively wet state may be sucked into the gap of the platform. In addition, if a large amount of polishing slurry is absorbed and the weight of the ring-shaped shielding member is increased, the rotation state of the polishing pad may be affected. Therefore, when the ring-shaped shielding member is provided with a water-absorbing property, it is required to be a moderate water-absorbing property. Specifically, the shielding member is preferably one having a mass increase rate (water absorption rate for 1 hour) of 60% by weight or less after being immersed in water at a temperature of 20 ° C for 1 hour.

However, water absorption is not a necessary function for the annular shielding member. This is because if the shape and size of the shield member are appropriately set as described above, the polishing slurry can be effectively scattered and the purpose can be achieved. In consideration of the increase in mass due to absorption of the polishing slurry, it may be preferable that the shielding member does not have water absorption. Therefore, the annular shielding member may be formed of a material having no water absorption or a material having low water absorption. In this case, the 1-hour water absorption of the shielding member may be set to 0% to 1%.

As the constituent materials of the ring-shaped shielding member, cellulose, rubber (butadiene rubber, chloroprene rubber, etc.), vinyl resin (polyvinyl alcohol (PVA), ethylene-vinyl acetate (EVA), vinyl chloride ( (PVC), etc.), styrene resin (polystyrene (PS), etc.), polycarbonate (PC), fluororesin (Teflon (registered trademark): PTFE, etc.), polyurethane (PU) . A shielding member composed of these materials and having a morphological structure of fibers, nonwoven fabrics, foams, porous bodies, and bulk (dense bodies) can be used.

The ring-shaped shielding member is preferably firmly bonded to the adsorption layer. This is because if the polishing slurry penetrates the interface between the annular shielding member and the adsorption layer, there is a concern that the shielding member peels off. Therefore, as in the case where the polishing layer is bonded to the substrate or the substrate is bonded to the adsorption layer, the shielding member is preferably bonded to the adsorption layer with an adhesive or an adhesive.

In addition, an adsorption layer composed of a polysiloxane composition, which is the same as the adsorption layer, may be formed on the surface of the shielding member and bonded to the adsorption layer of the polishing pad. The polysiloxane composition used in the present invention exerts a strong bonding force between the same materials. At this time, not only the horizontal direction but also the vertical direction can be firmly joined. As long as the adsorption layers are bonded to each other, the intrusion of the polishing slurry does not occur, and peeling of the shielding member can be prevented.

B. Polishing method using the polishing pad of the present invention

Next, a polishing method using the polishing pad of the present invention will be described. The basic method of the polishing method of the present invention is the same as the method using a conventional polishing pad having an adsorption layer. That is, the polishing pad is adsorbed and fixed on the platform, the polishing pad is rotated while the polishing slurry is supplied, and the member to be polished is pressed against the polishing pad to perform the polishing operation. The polishing pad is placed on the platform, and the polishing pad is pressed toward the platform from the polishing layer side, thereby fixing the polishing pad. At this time, it is not necessary to press the entire surface with rigorous uniform force, as long as the surface of the polishing layer is lightly touched and pressed, the adsorption effect of the adsorption layer can be exerted.

The polishing method of the present invention is characterized by selecting the size of the polishing pad to be used. In the present invention, a polishing pad having a diameter larger than the diameter (outer diameter) of the stage is used. In the polishing pad of the present invention, since the annular shielding member along the outer periphery of the polishing pad is bonded to the adsorption layer, the diameter plateau of the polishing pad must be equal to or longer than its width. The difference between the diameter of the polishing pad and the diameter of the platen is preferably 10 mm or more and 50 mm or less. This is set in consideration of a preferable value (5 mm) of the width of the shielding member. In addition, if the polishing pad is excessively larger than the stage, the rotation operation becomes unstable, and there is a concern that distortion or fluctuation may occur on the polishing pad surface.

In addition, as described above, when the polishing pad is fixed to the platform, the side surface of the ring-shaped shielding member of the polishing pad and the side surface of the platform may be in contact with each other, or may be spaced apart from each other.

While paying attention to the selection of the above-mentioned polishing pads, general polishing operations can also be performed after they are fixed on the platform by adsorption. In the present invention, the material, shape, and size of the object to be polished are completely unlimited.

During the polishing operation, the polishing slurry is supplied between the member to be polished and the polishing pad. There are no restrictions on the composition (the material of the abrasive grains, the particle size, the type of solvent, the concentration of the slurry, etc.) or the presence or absence of additives (surfactants, thickeners, etc.) and types of the polishing slurry supplied during this polishing operation. However, the present invention is particularly useful for grinding operations using a low-viscosity grinding slurry. This is because the low-viscosity abrasive slurry easily penetrates the bonding interface between the adsorption layer and the platform. The present invention is an effective polishing slurry whose polishing viscosity at 20 ° C is 10 mPa · s or less. In addition, it is also effective for polishing slurry of 3 mPa · s or less, and also effective for polishing slurry of 1.5 mPa · s or less. Even with a low viscosity slurry of 0.01 mPa · s, peeling of the polishing pad is unlikely to occur.

The members to be polished are sequentially polished and replaced when it is observed that the polishing pad is consumed. At this time, as in the past, if the polishing pad is moved upside from the polishing pad and air enters the interface, the fixing of the polishing pad can be easily released. Then, a new polishing pad having the same structure was fixed to the table and the polishing operation was continued.

The polishing pad of the present invention has an adsorption layer composed of a predetermined polysiloxane composition, and is provided with a ring-shaped shielding member on the surface of the adsorption layer. According to the present invention, it is possible to prevent the polishing pad from shifting or peeling due to the intrusion of the polishing slurry between the adsorption layer and the platform. Thereby, even in a long-term polishing operation, the operation is not interrupted due to the defect of the polishing pad, and an efficient operation can be performed. In addition, in the present invention, the original function of the adsorption layer is ensured, so the operability of replacing and fixing the polishing pad is also good.

FIG. 1 is a diagram illustrating a state where the polishing pad of the present invention is fixed to a stage.

Fig. 2 is a diagram illustrating the operation state of a polishing slurry when a polishing operation is performed according to the present invention.

FIG. 3 is a diagram showing an example of a cross-sectional shape of a ring-shaped shielding member.

FIG. 4 is a diagram illustrating the appearance and cross-sectional structure of the polishing pad manufactured in this embodiment.

Fig. 5 is a schematic diagram of a polishing apparatus used in this embodiment.

FIG. 6 is a diagram illustrating the configuration of a polishing pad provided with an adsorption layer.

Hereinafter, preferred embodiments of the present invention will be described. In this embodiment, a polishing pad having a ring-shaped shielding member bonded to a conventional polishing pad having an adsorption layer is manufactured, and a polishing operation of a silicon wafer is performed.

FIG. 4 is a view showing the appearance of the polishing pad manufactured in this embodiment. The polishing pad manufactured in this embodiment is a circular sheet, which has a polishing layer on the surface and an adsorption layer on the back. The polishing layer and the adsorption layer are supported by a substrate. In addition, the adsorption layer is provided with a ring-shaped shielding member along the outer periphery of the polishing pad (adsorption layer).

Here, each constituent member and manufacturing process of the polishing pad of this embodiment are demonstrated. First, the substrate is a circular sheet (thickness: 50 μm, outer diameter: 850 mm) made of PET, which is a resin material. A coating liquid containing a polysiloxane component containing a polyorganosiloxane is applied on one surface (back surface) of the substrate to form an adsorption layer. The coating liquid is a non-solvent type polysiloxane, which contains 0.6 parts by weight of 100 parts by weight of polysiloxane (molecular weight 30,000) containing a linear polyorganosiloxane having a vinyl group only at both ends. Crosslinking agent, 2 parts by weight of platinum catalyst. After this coating liquid is applied to a substrate, it is fired at 150 to 160 ° C for 100 seconds to crosslink the polysiloxane to form an adsorption layer. The thickness of the adsorption layer after crosslinking was 30 μm.

The abrasive layer formed on the other side of the substrate is a general-purpose ester abrasive cloth (model 7355-000FE) with a suede texture and a circular abrasive cloth (thickness 1.37mm) with a nap length of 450 μm. In this aspect, an abrasive layer is adhered to the other surface of the substrate on which the adsorption layer is formed with an acrylic adhesive.

In addition, the material of the ring-shaped shielding member is composed of a cellulose-based nonwoven fabric (30% water absorption). The dimensions of the shielding member are 850 mm in outer diameter, 800 mm in inner diameter (25 mm in width), and 10 mm in thickness. The diameter of the polishing pad and the inner diameter of the ring-shaped shielding member in this embodiment are set in consideration of the outer diameter of the platform of the polishing apparatus used in the polishing test described later. That is, the diameter of the polishing pad is set to be larger than the outer diameter of the platform by 800 mm, and the inner diameter of the annular shielding member is set to be substantially equal to the outer diameter of the platform. In this embodiment, the ring-shaped shielding member is adhered to the adsorption layer with an acrylic adhesive. Thereby, the polishing pad of this embodiment is manufactured.

Next, a polishing test was performed using the polishing pad of this embodiment. This polishing test was carried out by mounting a polishing pad of this embodiment on a platform (outer diameter 800 mm, manufactured by SUS) of a polishing apparatus as shown in FIG. Grinding. When the polishing pad is installed, the ring-shaped shielding member is embedded in the platform and pressurized from above the polishing layer. Then, the silicon wafer as a member to be polished is pressed onto the polishing layer and rotated, and the polishing slurry is dropped (flow rate 150 ml / min) to the polishing layer to perform the polishing operation.

The polishing slurry is obtained by diluting pure water with a surfactant using a commercially available abrasive (brand name Glanzox, manufactured by Fujimiinc Co., Ltd.) containing colloidal silica as abrasive particles (abrasive: pure water: interface activity) Agent = 70: 25: 5). The viscosity of the grinding slurry was 0.7 mPa. s.

Other polishing conditions are as follows.

‧Grinding pressure: 0.163kgf / cm ²

‧Rotating speed of polishing pad: 45rpm

‧Rotating speed of the member to be ground: 47rpm

‧Shaking speed of grinding head: 250mm / min

‧Grinding time: 60min, 480min

After the polishing operation is performed at each of the above polishing times, the close state of the polishing pad and the table is visually confirmed, and it is investigated whether the polishing pad is shifted or peeled. As a result, no deviation or peeling of the polishing pad was observed whether the polishing was performed in a short time of 60 minutes or the polishing was performed in a long time of 480 minutes. In addition, after the wafer after the polishing operation was washed with pure water and dried, the surface to be polished was observed, and as a result, no obvious scratch was observed at all.

Comparative example: In order to compare with the polishing pad of this embodiment, the polishing test was performed using the conventional polishing pad (FIG. 6) provided with the adsorption layer. The polishing pad of this comparative example has basically the same structure as the polishing pad of this embodiment, and includes a polishing layer and an adsorption layer on each surface of the substrate. The constituent materials and manufacturing steps of the polishing layer and the adsorption layer are the same as those of the polishing pad of this embodiment. However, the ring-shaped shielding member was not bonded to the adsorption layer. The outer diameter of the polishing pad of the comparative example is approximately equal to the outer diameter of the stage.

The polishing pad of the comparative example was adsorbed and fixed to a platform in the same manner as in the embodiment, and was polished under the same polishing conditions as described above. As a result, no polishing pad shift or peeling was observed during polishing in a short time of 60 minutes. . However, when polishing was performed for a long time of 480 minutes, the polishing pad shift started when 250 minutes passed, and the problem of peeling occurred. Therefore, the effect of the ring-shaped shielding member on the adsorption layer in the present invention can be confirmed.

    [Industrial availability]    

As described above, the polishing pad of the present invention does not shift or peel off from the platform even during a long-term polishing operation, and can maintain a fixed state. According to the present invention, a stable polishing operation can be performed while maintaining the convenience provided by the adsorption layer. According to the present invention, it is possible to form a polished surface with high accuracy even for wafers and display panels that are becoming larger in diameter and larger in area.

Claims (5)

    A polishing pad is composed of a substrate, an adsorption layer formed on one surface of the substrate, and a polishing layer formed on the other surface of the substrate; wherein, the polishing pad is formed by the adsorption layer during a polishing operation. Adsorb, fix on the platform and supply the grinding slurry to the grinding layer, and the user; the adsorption layer contains a composition crosslinked by at least one polysiloxane selected from the group consisting of the following: Polysiloxane containing a linear polyorganosiloxane having a vinyl group at the end, polysiloxane containing a linear polyorganosiloxane having a vinyl group at both ends and side chains, and polysiloxane containing a group having a vinyl group only at the end. Polysiloxane of branched polyorganosiloxane and polysiloxane containing branched polyorganosiloxane having vinyl groups at the end and side chains; in order to prevent the grinding slurry from entering the interface between the adsorption layer and the platform A ring-shaped shielding member is provided on the adsorption layer along the outer periphery of the polishing pad.         The polishing pad according to item 1 of the scope of patent application, wherein the cross-sectional shape of the shielding member is rectangular, or one side or both sides of the lower end are chamfered rectangles.         The polishing pad according to item 1 or 2 of the scope of patent application, wherein the width of the shielding member is 5 mm or more and the thickness is 10 mm or more and 50 mm or less.         The polishing pad according to any one of claims 1 to 3, wherein the shielding member is made of fiber, rubber, vinyl resin, styrene resin, polycarbonate, fluororesin, polyurethane It is composed of any one of the esters.         A polishing method using a polishing pad as described in any one of claims 1 to 4 of the scope of patent application for a polishing operation; wherein a diameter larger than the diameter of the platform is used and an annular shielding member is provided on the adsorption layer The polishing pad is adsorbed and fixed on the platform, and a polishing slurry is supplied to the polishing layer of the polishing pad to perform a polishing operation.