KR20010074676A - Workpiece retainer and method for attaching/detaching workpiece by using the same - Google Patents

Abstract

The present invention relates to a workpiece retainer containing an adhesive composition having a pressure-sensitive adhesive and a side-chain determinable polymer containing an amount of about 1 to about 30 weight percent of the adhesive composition. The polymer relates to a workpiece retainer characterized by containing as its main component acrylic esters and / or methacrylic esters having straight chain alkyl groups containing 16 or more carbon atoms.

Description

Workpiece retainer and method for attaching / detaching workpiece by using the same}

In recent years, the density of ICs in the semiconductor industry is increasing rapidly. It has increased from 4M to 16M and is now increasing to 64M.

In light of this situation, improvement of the surface quality of the wafer on which the IC is formed is rapidly required for cost reduction. In order to increase the degree of integration of the IC, it is necessary to reduce the minimum width allocated to the mechanism mounted on the wafer, and also to improve the chemical and electrical properties of the wafer. The ideal minimum width is shifting from about 0.5 microns to about 0.35 microns.

Such high precision machining requires even more stringent demands on the accuracy of flatness or thickness of the wafer surface. In particular, wafers requiring final Miller-surface polishing require a total thickness variation (TTV) of 1 μm or less with respect to the total area and a partial thickness variation (LTV) of 0.2 μm or less within about 20 mm 2. (E.g., a general part of a single IC chip).

In order to meet such precision requirements, it is required that the wafer be attached exactly and substantially parallel to the substrate surface of the polishing machine.

Generally, wax is used to attach the wafer to the substrate of the polishing machine. This method applies molten wax to the heated substrate surface through which the wafer adheres to the substrate surface.

According to this method, the wafer is first fixed by polishing onto the substrate surface, and after finishing, the substrate is heated again to melt the wax thereon to remove the wafer from the substrate surface and to remove the wax from the wafer. It is washed with an organic solvent.

Although this method can minimize the thickness variation of the polished wafer, it includes heating / cooling the substrate before and after polishing. Therefore, this method requires a heating step that requires heating to melt the wax and a step of using a harmful organic solvent to clean the wax. Moreover, the presence of gelled material or foreign particles in the wax can cause the surface of the wafer to penetrate during polishing. Thus, the final polishing quality is lowered. In addition, in the post-polishing cleaning, it may cause a small etch on the surface of the wafer.

(Initiation of invention)

The workpiece retainer according to the present invention contains an adhesive composition having a side-chain determinable polymer containing an amount of about 1 to about 30 weight percent of the pressure-sensitive adhesive and the adhesive composition, and furthermore, the side-chain crystal Possible polymers contain, as main components, acrylic esters and / or methacrylic esters having straight chain alkyl groups containing 16 or more carbon atoms in the side-chain.

In another embodiment of the present invention, the adhesive composition has an adhesive tackifier of about 10 to about 30 weight percent; The adhesiveness of the adhesive composition is one in which at least 90% of a decrease in adhesion occurs when heated to about 50 ° C.

In another embodiment of the invention, the side-chain determinable polymer has a molecular weight of about 2,000 to about 15,000.

As another embodiment of the present invention, the adhesive composition exhibits sufficient adhesion to the workpiece in the temperature range from room temperature to about 45 ° C. and easily detaches at about 50 ° C.

As another embodiment of the present invention, the side-chain determinable polymer has a melting point resulting in a temperature range narrower than about 15 ° C.

Optionally, the workpiece retainer according to the present invention comprises a first pressure sensitive adhesive layer to which the workpiece is attached; A support formed on the bottom surface of the first pressure-sensitive adhesive layer; And a second pressure sensitive adhesive layer formed on the underside of the support, wherein the first pressure sensitive adhesive layer comprises a side chain containing an amount of about 1% to about 30% by weight of the pressure sensitive adhesive and the adhesive composition. It contains an adhesive composition with a determinable polymer. In addition, the side-chain determinable polymer contains, as its main component, an acrylic ester and / or methacrylic ester having a straight alkyl group containing 16 or more carbon atoms in the side-chain.

In another embodiment of the present invention, the adhesive composition has an adhesive tackifier of about 10 weight percent to about 30 weight percent; The adhesiveness of the adhesive composition is one in which at least 90% of a decrease in adhesion occurs when heated to about 50 ° C.

In another embodiment of the invention, the side-chain determinable polymer has a molecular weight of about 2,000 to about 15,000.

As another embodiment of the present invention, the adhesive composition exhibits sufficient adhesion to the workpiece in the temperature range from room temperature to about 45 ° C. and easily detaches at about 50 ° C.

As another embodiment of the present invention, the side-chain determinable polymer has a melting point resulting in a temperature range narrower than about 15 ° C.

Another aspect of the invention provides a method of attaching / detaching the workpiece retainer from a substrate of a polishing machine, which attaches a workpiece retainer between at least one workpiece and a substrate of the polishing machine while maintaining a T1 temperature; Detaching the workpiece from the substrate by heating the workpiece retainer to a temperature T2 higher than the temperature T1.

The present invention has the following effects.

According to an embodiment of the invention the workpiece retainer comprises an adhesive composition having a pressure sensitive adhesive and a side-chain determinable polymer, wherein the side-chain determinable polymer is from about 1 weight percent to about 30 weight percent of the adhesive composition Has a content of. Side-chain determinable polymers contain acrylic and / or methacrylic esters having, as their main components, straight-chain alkyl groups containing 16 or more carbon atoms in the side-chain. As a result, the polymer is able to move between the crystalline and amorphous states in a reversible manner, reacting with a small temperature change that can be arbitrarily selected in a relatively common temperature range, and as a result the polymer is large on the substrate surface. A change in adhesiveness is shown.

Therefore, when heating the workpiece retainer to a predetermined elevated temperature such as, for example, about 50 ° C. to about 100 ° C., the adhesion of the adhesive layer decreases rapidly. Therefore, when detaching a workpiece from the workpiece retainer, the workpiece retainer (and / or any substrate attached to the workpiece retainer such as, for example, the upper substrate) greatly reduces the adhesion of the adhesive layer on the workpiece surface. Heating to make the workpiece retainer easily detachable.

According to an embodiment of the present invention, the adhesive composition contains an adhesion enhancer in an amount of about 10% to about 30% by weight and is reduced to about 90% or more of the adhesive composition upon warming to about 50 ° C. At room temperature, a certain level of adhesion to the substrate surface is maintained, but the adhesion is significantly reduced by heating. Therefore, the content of the adhesion enhancer described above does not substantially affect the thermal sensitization of the polymer. As a result, the adhesive composition according to the present invention maintains a strong and sufficient adhesiveness at room temperature, but gives a force that can be detached at an elevated temperature to maintain a good balance with the adhesive strength at room temperature.

Therefore, in view of the possible advantages described in the present invention, (1) it provides a workpiece retainer capable of attaching the workpiece to the substrate of the polishing machine powerfully, stably and precisely, and also washing with conventional organic solvents and / or surfactants and the like. Provide that the workpiece can be easily detached from the substrate without having to. (2) A method for attaching / detaching a workpiece using a workpiece retainer is provided.

These advantages of the present invention can be clearly understood in the art by referring to the detailed description of the present invention and the drawings of the present invention.

The present invention relates to a workpiece retainer attached to a substrate of the polishing machine for holding the workpiece (eg, semiconductor wafer or precision glass) in place while polishing the workpiece and using the workpiece retainer from the substrate of the polishing machine. To a method for attaching / detaching a workpiece.

1 shows a cross-sectional view of one embodiment of a workpiece retainer according to the present invention when the workpiece retainer is attached to the upper substrate of the polishing machine and the wafer is attached to the workpiece retainer.

Figure 2 shows a cross-sectional view of another embodiment of a workpiece retainer according to the invention when the workpiece retainer is attached to the upper substrate of the polishing machine and the wafer is attached to the workpiece retainer.

The workpiece retainer according to the present invention contains an adhesive composition consisting of a pressure-sensitive adhesive and a side-chain determinable polymer having a melting point resulting in a temperature range narrower than about 15 ° C. The adhesive composition exhibits adhesion at room temperature T1 (generally below about 40 ° C. to 50 ° C.), but decreases adhesion upon heating to elevated temperature (T2), which is about 15 ° C. or more above room temperature T1.

As shown in Figure 1, the workpiece retainer 1 of the present invention comprises a single layer on a work substrate, such as a substrate of a polishing machine. Alternatively, as shown in FIG. 2, the workpiece retainer 1 may consist of three layers containing a support in the intermediate layer. As shown in Fig. 2, the three-layer workpiece retainer has a first pressure-sensitive adhesive layer 2 (consisting of the adhesive composition of the present invention) formed on one side of the support sheet 3, and the second The pressure-sensitive adhesive layer 4 is formed on the other side of the support sheet 3.

The secondary pressure-sensitive adhesive layer (4) is (1) a commercially available pressure sensitive adhesive (2) a mixture of a commercially available pressure sensitive adhesive with the adhesive composition of the present invention or (3) a temperature sensitive, ie adhesive It may contain a pressure-sensitive adhesive which is reduced in response to.

(Pressure-sensitive adhesive layer)

Examples of the pressure-sensitive adhesive containing the adhesive composition of the pressure-sensitive adhesive layer of the present invention may include the following materials. Natural rubber adhesives; Styrene / butadiene latex base adhesives; ABA block copolymer type thermoplastic rubber, where A denotes a thermoplastic polystyrene end block and B denotes an intermediate block of rubber such as polyisoprene, polybutadiene or poly (ethylene / butylene); Butyl rubber; Polyisobutylene; Acrylic adhesives such as polyacrylates and vinyl acetate / acrylic ester copolymers; Vinyl ether copolymers such as polyvinyl methyl ether, polyvinyl ethyl ether and polyvinyl isobutyl ether.

In particular, preferred acrylic pressure-sensitive adhesives consist of ethylhexyl acrylate, hydroxy ethyl acrylate or the like. The use of acrylic type pressure sensitive adhesives provides polymer interaction as a polymer that can be sufficiently dispersed in the pressure sensitive adhesive layer to exhibit sufficient adhesion at a predetermined temperature. However, it easily loses tack when heated to a predetermined temperature.

(Side-chain determinable polymer)

As side-chain determinable polymers included in the adhesive composition, those having a melting point within a temperature range narrower than about 15 ° C. (hereinafter referred to as 'primary melt transition') are preferably used. Adhesive compositions containing such polymers are disclosed in Japanese Patent Laid-Open No. Hei 6-510548.

As used herein, the term 'melting point' refers to the temperature at which the equilibrium reaction occurs at a portion of the polymer, and the temperature at which aligned arrays begin to relocate and lose balance. In an embodiment of the present invention preferably the melting point of the polymer is in the range of about 40 to 100 ° C, more preferably in the range of about 40 to 60 ° C. More preferably, the melting is caused rapidly to occur within a temperature range relatively less than 10 ° C., more preferably less than 5 ° C. It is desirable for the polymer to crystallize rapidly. Seeding agents or crystallization catalysts can be used in combination with the polymer for this purpose.

After use, the workpiece retainer according to the invention raises the temperature of the workpiece retainer slightly above the operating temperature (hereinafter referred to as 'heating') so that it can be easily detached from the substrate surface of the polishing machine by simply heating it. The elevated temperature is usually about 40 ° C. to about 100 ° C., preferably about 40 ° C. to about 70 ° C., and more preferably about 50 ° C. to about 70 ° C.

The present invention is due to the following invention, which is possible by mixing a determinable polymer having a physicochemical property of pressure-sensitive adhesiveness to obtain an adhesive composition capable of adjusting the adhesion according to the temperature.

A preferred form of the side-chain determinable polymer according to the invention is to have a repeating unit of the formula

... (Ⅰ)

In formula (I), W and X are the first and second monomer units, each of which is any molecular moiety linked with an adjacent molecular moiety (eg, polymerizable). Y and Z, independently of one another, represent a backbone that can be any molecular moiety or atom. Each S independently represents a linking group or spacer, optionally present. Cyt and Cy each independently represent a determinable moiety that is linked with the backbone either directly or through a spacer unit. The variables a, b, c and d each independently represent an integer between 0 and 1000 and Cyt and Cy must be sufficient to provide a molecule that is equal to or more than twice the sum of the molecular weights of W, X, Y and Z. do. The polymer has a heat of fusion (ΔHf) of at least about 20 joules / gram. Monomer units W, X, Y and Z are defined as repeating units or mixtures of different monomer units when the variables a, b, c and d are all greater than one. For example, when a is 100, W may be a 5: 5: 2: 5: 83 mixture of styrene, acrylic acid, methylstyrene and hexadecylacrylate. Thus, any monomer unit of W, X, Y and Z can be a mixture of polymerizable monomers.

The adhesive composition of the present invention may optionally have a cross link. Crosslinking can be effectively obtained by, for example, a method of crosslinking agent, heating or irradiation.

The backbone of the polymer (represented by W, X, Y and Z of formula (I)) may be of organic structure (aliphatic or aromatic hydrocarbons, esters, ethers, amides, etc.) or inorganic structures (sulfide, phosphazine, silicone, etc.). have. Spacer linkages are suitable for organic or inorganic units, for example esters, amides, hydrocarbons, phenyls, ethers or (e.g., carboxyl-alkyl ammonium or sulfonium or phosphonium ion pairs, or other known ions). Inorganic salts). Side-chains (denoted Cyt and Cy and optionally represented by S in formula (I)) are aliphatic or aromatic or a combination of aliphatic side-chains having at least 10 carbon atoms, or fluorinated with at least 6 carbon atoms Aliphatic side-chains, and p-alkylstyrene side-chains containing alkyl having 8 to 24 carbon atoms.

The length of each side-chain moiety is generally about five times greater than the length of the side-chain for acrylates, methacrylates, vinylesters, acrylamides, methacrylamides, vinylethers and alphaolefins. In the case of copolymers of fluoroacrylate and butadiene, the side-chain can be about 2 times shorter than the length between branches. In any case, the content of the side-chain units accounts for at least about 50% of the polymer volume, preferably at least about 65%. Comonomers added to side-chain polymers generally exhibit side effects in crystallization. Small amounts (typically from about 10% to about 20% by volume) of various comonomers are acceptable. In some cases, it is preferable to add small amounts of comonomers, such as, for example, acrylic acid, glycidal methacrylate, maleic anhydride, aminofunctional monomers and the like.

Examples of side-chain determinable monomers include materials falling within the above categories, such as acrylates, fluoroacrylates, methacrylates and vinyl ester polymers. These include J. Poly. Sci. 10: 3347 (1972); J. Poly. Sci. 10: 1657 (1972); J. Poly. Sci. 9: 3367 (1971); J. Poly. Sci. 9: 3349 (1971); J. Poly. Sci. 9: 1835 (1971); J.A.C.S. 76: 6280 (1954); J. Poly. Sci. 7: 3053 (1969); J. Poly. Sci. 17: 991 (1985), the corresponding acrylamide, substituted acrylamide and maleimide polymers are described in J. Poly. Sci .: Poly. Physics Ed. 18: 2197 (1980), polyalpha-olefin polymers are described in J. Poly. Sci .: Macromol. Rev. 8: 117-252 (1974) and Macromolecules 13: 12 (1980), polyalkyl-vinylether, polyalkylethylene oxides are described in Macromolecules 13: 15 (1980), alkylphosphazene polymers, poly The amino acid is J. Poly. Sci. USSR 21: 241 (1979), Macromolecules 13: 2141 (1985), polyisocyanates are described in Macromolecules 12: 94 (1979), prepared by amine or alcohol reactions comprising long chain alkyl isocyanate monomers. Polyurethanes, polyesters and polyethers, polysiloxanes and polysilanes are described in Macromolecules 19: 611 (1986), p-alkylstyrene polymers 75: 3326 (1953), triglycerides such as tristealine or pentaerythritol tetrastearate.

Preferred examples of side-chain determinable polymers used in the present invention include linear aliphatic C14-C50 (with carbon atoms 14-50), polyaliphatic C14-C50 polymethacrylates, linear aliphatic C14-C50 polyacrylates Amides and linear aliphatic C14 to C50 polymethacrylamides. More preferably, they are linear aliphatic C16-C22 polyacrylate, linear aliphatic C16-C22 polymethacrylate, linear aliphatic C16-C22 polyacrylamide, linear aliphatic C16-C22 polymethacrylamide, etc.

As mentioned above, the melting point of the selected determinable polymer is defined to be used within a temperature range in which the composition exhibits adhesion. The amount of determinable polymer used with the adhesive composition has only a minor effect on the location or width of this range.

The transition temperature of the selected side-chain determinable polymer is as follows.

Polymer transition temperature (℃)

C16 acrylate 36

C16 methacrylate 26

C18 acrylate 49

C18 methacrylate 39

C20 acrylate 60

C20 methacrylate 50

C22 acrylate 71

C22 methacrylate 62

'Side-chain crystallization degree Ⅱ' by J. Poly and J. Poly. Sci. See Section A-1, 9: 33551 (1971). The literature describes in detail how to make determinable polymers.

The molecular weight of the determinable polymer is a very important factor in determining the use of the adhesive composition of the present invention and exhibiting temperature dependent adhesion and adhesion. In particular, low molecular weight determinable polymers lose their effective binding upon heating. If such properties are required, the molecular weight range of the polymer is preferably 2,000 to 15,000 and more preferably 3,000 to 10,000.

Adhesive compositions for use in the present invention may include, in addition to one or more of the above polymers, wood rosin, adhesion enhancers such as polyesters, antioxidants, fibrous or nonfibrous fillers, colorants and the like. Additional adhesives may be included in the present adhesive composition as long as they do not significantly affect the thermal sensitivity of the adhesive composition. The amount of determinable polymer in the adhesive composition is preferably from about 1% to 30% by weight, more preferably from about 5% to about 20% by weight, particularly preferably from about 5% to about 15% by weight. If the polymer contained in the adhesive composition is about 1 wt% or less or about 30 wt% or more, the above effects cannot be obtained from the polymer.

The adhesive composition of the present invention may be prepared after the pressure-sensitive adhesive and the determinable polymer are mixed with an appropriate solvent by selectively adding other components such as plasticizers, adhesion enhancers and / or reinforcing agents. The solid component should be adjusted to the appropriate viscosity and the mixture is blended until it is homogenized. Remove air bubbles from the mixture after blending.

Examples of the adhesion enhancer of the present invention include rosin ester adhesion enhancers, terpene phenolic adhesion enhancers, petroleum resin adhesion enhancers, high hydroxide rosin ester adhesion enhancers, hydrogenated rosin ester adhesion enhancers, and the like. Examples of commercially available articles include rosin ester adhesive enhancers such as Super Ester A125 from Arakawa Chemical Co., Ltd., and terano phenol type adhesive enhancers include Tamanoru 803L from Arakawa Chemical Co., Ltd., petroleum resin type. Examples of the adhesion enhancer include Hiresin # 90S manufactured by Toho Chemical Industries Co., Ltd., and the high hydroxyl value rosin ester adhesion enhancer is KE-364C from Arakawa Chemical Co., Ltd., and the hydrogenated rosin ester adhesion enhancer is Arakawa Chemical Co. Geisha's Estergum HD.

Particularly preferred examples thereof include rosin ester adhesion promoters. The amount of adhesion promoter may be added to the adhesive composition, preferably in the range of about 10% to about 30% by weight, more preferably in the range of about 15% to about 25%. If the amount of the adhesion enhancer is lower than 10% by weight, sufficient adhesion strength may not be obtained at room temperature. If the amount of the adhesion enhancer exceeds 30% by weight, a sufficient decrease in the adhesion strength is not achieved when detaching.

Preferred examples of the polymer contained in the adhesive composition include the following.

(1) a copolymer of 80 to 98 parts by weight of stearyl acrylate, 2 to 20 parts by weight of acrylic acid and 2 to 10 parts by weight of dodecylmercaptan

(2) a copolymer of 5 to 90 parts by weight of docosyl acrylate, 5 to 90 parts by weight of stearyl acrylate 1 to 10 parts by weight of acrylic acid and 2 to 10 parts by weight of dodecylmercaptan

(3) a copolymer of 80 to 98 parts by weight of docosyl acrylate, 2 to 20 parts by weight of acrylic acid and 2 to 10 parts by weight of dodecylmercaptan

As an example of the pressure-sensitive adhesive agent contained in an adhesive composition, the copolymer of 80-95 weight part 2-ethylhexyl acrylate and 5-20 weight part 2-hydroxyethyl acrylate is mentioned.

(Support sheet)

As the support sheet 3, for example, a synthetic resin sheet such as polyethylene terephthalate, polyetherimide, or polyurethane can be used. For example, a polyester film such as "Lumirror" (manufactured by Toray Industries, Inc.) may be used.

The adhesive composition of the present invention can be provided on a work substrate (such as a substrate of a polishing machine) or a workpiece in various ways. For example, spray deposition, painting, dipping, gravure printing, rolling or similar methods can be used. The polymer composition can be delivered from the release sheet in the same way as transfer printing. The composition may be applied on its own (without other additives) or in the form of a suitable solvent or emulsion or latex. Optionally, a mixture of suitable monomers and additives may be applied to the substrate and subjected to heating, irradiation or other suitable known methods in situ.

In the case of a workpiece retainer having three or more layers, the pressure-sensitive adhesive layer described above may be laminated on one or both sides of the support, and the secondary pressure-sensitive adhesive layer may be laminated on another side of the support. The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer of the present invention can be used as a secondary pressure-sensitive adhesive. For example, commercially available adhesives, in particular rubber adhesives, acrylic adhesives, semi-hotmelt adhesives and the like, may be used as the secondary pressure sensitive adhesive.

(How to attach / remove the workpiece)

Attachment / detachment of the workpiece from the substrate of the polishing machine using the workpiece retainer of the present invention can be performed, for example as follows.

First, the substrate of the polishing machine is removed and cleaned. The workpiece retainer is applied to the substrate by a spin coater. In the case of working a plate-shaped workpiece, the workpiece retainer is similarly applied to the workpiece by a spin-coater. The workpiece or substrate or both are then compressed by the workpiece retainer at normal temperatures (eg, about 20 ° C. to 30 ° C.). When polishing a semiconductor wafer, it is preferable to slightly warp the workpiece retainer, and the workpiece is gently compressed so that its central portion can contact the workpiece first.

After attaching the workpiece to the substrate of the polishing machine by the method described above by the desired method of the workpiece, the workpiece is removed, for example, by heating the substrate attached to the workpiece retainer at an elevated temperature of about 50 ° C. do. For example, the following heating method may be used.

(1) How to heat the workpiece retainer

This method may include methods such as heating iron, hot water, a heater sheet, hot air (eg, by an air heater or a dryer), steam, electromagnetic heating and / or irradiation of infrared or far infrared rays by a lamp. .

(2) A method of heating the interface between the workpiece retainer and the substrate

This method may include methods such as heating trowels, heated iron, hot air (eg, by air heaters or dryers), hot water, steam, and / or irradiation of infrared or far infrared rays by lamps. Can be.

(3) a method of heating the substrate

The method includes storing the substrate in a room maintaining a temperature of about 50 ° C. to about 100 ° C., or immersing the substrate in about 50 ° C. or more of hot water. The heated workpiece retainer is then detached from the substrate. The workpiece retainer of the present invention is easily detached from the substrate surface because the desorption force at elevated temperature is reduced to about 0.1 to about 0.5 kg / inch width. The removal of the workpiece retainer is performed manually.

Polymer compositions containing polymers exhibiting the temperature dependent adhesion profile can also be used as workpiece retainers, such as abrasive lenses, prisms or other precision glass materials. Optionally, such polymer compositions can be applied in a small amount evenly on a thin substrate sheet, to detach the substrate from the polymer composition, and to adhere the polymer composition onto the workpiece.

It is very convenient to attach the workpiece to the substrate and wash it through the machining process using the workpiece retainer of the present invention (temperature-dependent pressure retainer) containing a polymer exhibiting the above temperature-dependent adhesion profile. It may be easier than using a wax or a pressure-sensitive adhesive conventionally.

Hereinafter, the present invention will be described in more detail with reference to Examples. Here, 'part' means 'parts by weight'.

A. Preparation of Polymer

Synthesis Example 1

First, 95 parts of stearyl acrylate, 5 parts of acrylic acid, 5 parts of dodecyl mercaptan, and 1 part of Kayaester HP-70 (manufactured by vulcanizer) are mixed. The mixture is polymerized with stirring at about 80 ° C. for 5 hours. The resulting polymer has a molecular weight of about 8,000 and a melting point of about 50 ° C.

Synthesis Example 2

First, 92 parts of 2-ethylhexyl acrylate, 8 parts of hydroxyethyl acrylate, and 0.3 parts of Trigonox 23-C70 (manufactured by KKK) are mixed with 150 parts of ethyl acetate / heptane (70/30). The mixture is stirred at about 55 ° C. for 3 hours and 0.5 parts of Kayaester HP-70 is added at about 80 ° C. The mixture is stirred for about 2 hours and then polymerized. The resulting polymer has a molecular weight of about 600,000.

B. Preparation of Workpiece Retainer

(Example 1)

The polymers obtained in Synthesis Examples 1 and 2 are mixed at 10: 100. 0.3 part of Coronate L45 is added to the obtained polymer solution with respect to 100 parts of polymers of the synthesis example 2 with the crosslinking agent Coronate L45 (made by Nippon Polyurethane Industry Company). As shown in Fig. 2, the resulting mixture is coated on both sides of the support 3 (manufactured by PET film Soma Co.) so as to be 40 mu m. A double-sided adhesive tape is formed here.

As the workpiece retainer 1, a double-sided adhesive tape is attached to the ceramic substrate 5 of the polishing machine. The silicon wafer 6 (diameter: about 8 inches) is attached directly to the workpiece retainer 1 at an adhesion temperature of about 25 ° C. Thereafter, the wafer is polished under the polishing conditions shown in Table 1. After polishing is complete, the wafer attached to the ceramic carrier is immersed in a stream of pure water heated to about 60 ° C. for about 5 minutes. Here the wafer is detached from the ceramic carrier. Then visually identify which organic residues remain on the back of the wafer. The double-sided adhesive tape is detached from the ceramic top of the substrate with a maximum detachment force of about 1.3 kg.

(Example 2)

A polymer mixture was prepared in the same manner as in Example 1, except that Coronate L45 (manufactured by Nibon Polyurethane Industry Co., Ltd.) was added as a 0.5 part crosslinking agent with respect to 100 parts of the polymer of Synthesis Example 2. The spin-coater was applied directly onto the ceramic carrier of the polishing machine to a thickness of about 0.02 μm. The workpiece retainer is formed here. The silicon wafer is attached to the workpiece retainer at an adhesion temperature of about 25 ° C. Thereafter, the wafer is polished under the polishing conditions shown in Table 1. After polishing is finished, the wafer attached to the ceramic carrier is placed in a heated pure flow of about 60 ° C. for about 5 minutes. Then visually check that there are no organic residues left on the back of the wafer.

(Example 3)

A double-sided adhesive tape was prepared in the same manner as in Example 1 except that the adhesive enhancer Superester A125 (manufactured by Aragawa Chemical Co., Ltd.) was added to the polymer substrate prepared in Synthesis Example 1 in an amount of about 20%.

Next, the wafer polishing test was performed as in Example 1 using the obtained double-sided adhesive tape. After polishing is finished, the wafer attached to the ceramic carrier is placed in a heated pure flow of about 60 ° C. for about 5 minutes. Then visually check that there is no organic residue left on the back of the wafer on the silicon way surface.

(Example 4)

The double-sided adhesive tape used in Example 3 was attached directly to a 20 mm x 20 mm prism (manufactured by BK7). It is press-bonded to the substrate upper surface of the polishing machine at the adhesion temperature of about 25 ℃. The prism is then polished under the polishing conditions shown in Table 2. After polishing is finished, the prism attached to the upper substrate is placed in a heated pure flow of about 60 ° C. for about 5 minutes. Thereafter, the light transmittance measurement of the prism showed a sufficiently high state.

(Example 5)

First, 45 parts cetyl acrylate, 50 parts methyl acrylate, 5 parts acrylic acid and 0.5 parts azobisisobutyronitrile were mixed in a toluene solvent. The mixture was stirred at about 60 ° C. for 10 hours under a nitrogen atmosphere to polymerize these monomers. The resulting polymer has a molecular weight of about 700,000. The transition temperature from the non-adhesive state to the adhesive state of the obtained polymer is in the range of about 10 ° C to about 20 ° C. The polymer did not exhibit hand adhesion under about 10 ° C., indicating very low adhesion.

A double-sided adhesive tape was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive layer 4 was formed on the polymer with a dry thickness of about 45 μm (FIG. 2).

Next, the same polishing test as in Example 1 was carried out using the obtained double-sided adhesive tape. After polishing was completed, the wafer 6 attached to the ceramic carrier 5 was placed in a heated pure flow of about 60 ° C. for 5 minutes in a manner similar to Example 1. Then, the wafer 6 was detached from the ceramic carrier 5. At this point, the substrate 5 and the pressure-sensitive adhesive layer 4 adhered well while the pressure-sensitive adhesive layer 2 was easily detached from the interface between the silicon wafers 6. Thereafter, no material was observed on the backside of the silicon wafer. After further cooling the substrate 5 to about 5 ° C., the pressure-sensitive adhesive layer 4 was easily detached from the substrate 5.

(Example 6)

The double-sided adhesive tape was applied in the same manner as in Example 1 except that the pressure-sensitive adhesive layer 4 was formed with a commercially available rubber adhesive (manufactured by NO-TAPE Industries, Inc.) at a dry thickness of about 45 μm (FIG. 2). Prepared.

Next, the same polishing test as in Example 1 was carried out using the obtained double-sided adhesive tape. After polishing was completed, the wafer 6 attached to the ceramic carrier 5 was placed in a heated pure flow of about 60 ° C. for 5 minutes in a manner similar to Example 1. Then, the wafer 6 was detached from the ceramic carrier 5. At this point, the pressure-sensitive adhesive layer 2 was easily detached from the interface between the silicon wafers 6. Thereafter, no material was observed on the backside of the silicon wafer.

Furthermore, the silicon wafer was attached to the pressure-sensitive adhesive layer 2 and the same polishing test as in Example 1 was performed. The silicon wafer was then detached while being heated. At this point, the substrate 5 and the pressure-sensitive adhesive layer 4 adhered well while the pressure-sensitive adhesive layer 2 was easily detached from the interface between the silicon wafers 6.

A series of processes such as adhesion, polishing test, heating and desorption of the silicon wafer were repeated three times. The silicon wafer did not detach from the pressure-sensitive adhesive layer 2 during the polishing test period and exhibited satisfactory adhesion. No foreign matter was observed on the backside of the silicon wafer.

(Comparative Example 1)

The polishing test was performed under the same conditions except that the double-sided adhesive tape ST442 (manufactured by Sumitomo 3M) was used instead of the double-sided adhesive tape according to Example 1.

It was difficult to remove the wafer after the polishing test was completed. A detachment force of up to about 14.3 kg was required to detach the double-sided adhesive tape from the top surface of the ceramic substrate.

(Comparative Example 2)

As in Example 2, the receiving wax for the semiconductor wafer (viscosity: 10 cps; solid content: 10%) wax was directly coated on the ceramic carrier of the polishing machine to a thickness of about 0.20 mu m using a spin coater. The silicon wafer was attached with this composition at an adhesion temperature of about 80 ° C. Thereafter, the wafer was polished under the polishing conditions shown in Table 1. After polishing was finished, the ceramic carrier was detached using a pick and washed with pure water. Visual inspection showed the presence of residual wax on the top of the wafer, indicating that the wafer needs to be cleaned with an organic solvent.

(Comparative Example 3)

A commercially available rosin wax (viscosity: 100 cps; solid content: 50%) was applied directly onto a 20 mm x 20 mm prism (BK7). Press bonding was performed on the substrate top of the polishing machine at an adhesion temperature of about 100 ° C. Thereafter, the prism was polished under the conditions shown in Table 2. After polishing, the prism attached to the upper surface of the substrate is heated to detach from the upper surface of the substrate. Thereafter, the light transmission measurement of the prism showed a low measurement due to the presence of a large amount of residual wax. It was necessary to clean the prism.

Grinder Speed Pam Grinder with Substrate (59SPAW) Wafer processed Silicon Monocrystalline P (100) Wafer (Diameter: 8 inches) Abrasive cloth SUBA 800 Polishing Slurry NALCO2350; 20-fold dilution (manufactured by NALCO Chemical Co., Ltd.) Processing pressure 300 g / ㎠ Slurry flow rate 1000 ml / min Machining time 30 minutes

Grinder Speed Pam Grinder with Substrate (26B) Wafer processed Prism (20mm x 20mm; made by BK7) Abrasive cloth MH C14A-15 Polishing Slurry cerium oxide, Mireku S0; 20 wt% Processing pressure 150 g / ㎠ Slurry flow rate 500 ml / min Machining time 20 minutes

Therefore, according to the present invention, it is possible to adjust the adhesion of the workpiece retainer to the workpiece by simply changing the temperature of the workpiece retainer. As a result, it is possible to maintain a satisfactory adhesion to the workpiece retainer when polishing the workpiece, usually at room temperature, so that the workpiece can be strongly, stably and precisely adhered to the substrate of the polishing machine. On the other hand it is easy to properly detach the workpiece from the substrate by heating the workpiece retainer. Thus, the workpiece is protected from contamination by organic solvents and / or surfactants as in the prior art. It is also possible to provide a high quality final polishing state.

Moreover, the workpiece retainer can be easily detached from the substrate by simply adjusting the temperature after each polishing process when exchanging the workpiece retainer according to the present invention.

The adhesiveness of the workpiece retainer according to the invention can be repeatedly attached and detached from the workpiece retainer because it changes in a reversible manner simply by temperature control. For example, a silicon wafer can be processed repeatedly and removed from a substrate.

It will be apparent to those skilled in the art that various other modifications can be made by the scope and spirit of the invention. Accordingly, the scope of the claims is not limited to what is described in the specification but may be interpreted broadly.

Claims (11)

A workpiece retainer containing an adhesive composition having a pressure-sensitive adhesive and a side-chain determinable polymer containing an amount from about 1% to about 30% by weight of the adhesive composition, wherein the side-chain determinable polymer is a main component thereof. Workpiece retainers characterized in that they contain acrylic esters and / or methacrylic esters having straight chain alkyl groups containing 16 or more carbon atoms in the side-chain. The adhesive composition of claim 1, wherein the adhesive composition has an adhesion enhancer of about 10 to about 30 weight percent; Adhesion of the adhesive composition is a workpiece retainer, characterized in that at least 50% degradation in adhesion occurs when heated to about 50 ℃ The workpiece retainer of claim 1, wherein the side-chain determinable polymer has a molecular weight of about 2,000 to about 15,000. The workpiece retainer of claim 1, wherein the adhesive composition exhibits sufficient adhesion to the workpiece in the temperature range from room temperature to about 45 ° C., and easily detaches at about 50 ° C. 7. The workpiece retainer of claim 1, wherein the side-chain determinable polymer has a melting point resulting in a temperature range less than about 15 ° C. 3. A first pressure-sensitive adhesive layer to which the workpiece is attached; A support formed on the bottom surface of the first pressure-sensitive adhesive layer; And a second pressure sensitive adhesive layer formed on the underside of the support, wherein the first pressure sensitive adhesive layer contains from about 1% to about 30% by weight of the pressure sensitive adhesive and the adhesive composition. An adhesive composition having a side-chain determinable polymer, said side-chain determinable polymer comprising, as its main component, an acrylic ester and / or methacryl having a straight-chain alkyl group containing 16 or more carbon atoms in the side-chain Workpiece retainer characterized by containing acid esters The adhesive composition of claim 6, wherein the adhesive composition has an adhesion enhancer of about 10 weight percent to about 30 weight percent; Adhesion of the adhesive composition is a workpiece retainer, characterized in that at least 50% degradation in adhesion occurs when heated to about 50 ℃ 7. The workpiece retainer of claim 6, wherein the side-chain determinable polymer has a molecular weight of about 2,000 to about 15,000. The workpiece retainer of claim 6, wherein the adhesive composition exhibits sufficient adhesion to the workpiece in the temperature range from room temperature to about 45 ° C., and easily detaches at about 50 ° C. 8. 7. The workpiece retainer of claim 6, wherein the side-chain determinable polymer has a melting point that results in a temperature range narrower than about 15 [deg.] C. A method of attaching / detaching the workpiece retainer of claim 6 from a substrate of a polishing machine, comprising: attaching a workpiece retainer between at least one workpiece and a substrate of the polishing machine while maintaining a T1 temperature; Detaching the workpiece from the substrate by heating the workpiece retainer to a temperature T2 higher than the temperature T1.