JP2009231700A - Wafer processing tape - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wafer processing tape which will not oversoften, in heat treatment which uses a thermosetting-type surface protective film, can be used in an expansion step for splitting an adhesive layer, and has uniform and isotropic expansion property. <P>SOLUTION: This expandable wafer processing tape 10 is used for splitting an adhesive layer 13 along a chip by expansion and is provided with a base material film 11, a pasty layer 12 provided on the base material film 11, and an adhesive layer 13 provided on the pasty layer 12, wherein a lowermost layer 11b of the base material film is made of a thermoplastic resin, having a Vicat softening point of ≥80°C, as defined by JIS K7206; and at least one layer 11a, other than the lowermost layer 11b of the base material film, is made of thermoplastic resin, having a Vicat softening point of 50°C-80°C defined by JIS K7206. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an expandable wafer processing tape used when an adhesive layer is divided along a chip by an expand.

  In the manufacturing process of semiconductor devices such as ICs, a back grinding process that grinds the back surface of the wafer in order to thin the wafer after circuit pattern formation, and adhesive and stretchable wafer processing tape is applied to the back surface of the semiconductor wafer. After that, a dicing process for dividing the wafer into chips, a process for expanding the wafer processing tape, a process for picking up the divided chips, and bonding the picked-up chips to a lead frame, a package substrate, etc. In the package, a die bonding (mounting) process for stacking and bonding semiconductor chips together is performed.

  In the back grinding process, a surface protection tape for protecting the circuit pattern forming surface (wafer surface) of the wafer from contamination is used. When this surface protection tape is peeled off from the wafer surface after the backside grinding of the wafer, the wafer processing tape (dicing / die bonding tape) described below is bonded to the backside of the wafer, and then the dicing die is attached to the suction table. The bonding tape side is fixed, and the surface protective tape is subjected to a treatment for reducing the adhesive strength to the wafer, and then the surface protective tape is peeled off. The wafer from which the surface protection tape has been peeled is then picked up from the suction table with the dicing die bonding tape bonded to the back surface and subjected to the next dicing process. The treatment for reducing the adhesive force is energy ray irradiation treatment when the surface protective tape is made of an energy ray curable component such as ultraviolet rays, and the surface protective tape is made of, for example, a thermosetting component. When the adhesive force is controlled by heating, it is a heat irradiation (heating) process.

  In the dicing process to the mounting process after the back grinding process, a dicing die bonding tape in which an adhesive layer and an adhesive layer are laminated in this order on a base film is used.

  In general, when using a dicing die bonding tape, first, the adhesive layer of the dicing die bonding tape is fixed to the back surface of the semiconductor wafer to fix the semiconductor wafer, and then the semiconductor wafer and the adhesive layer are attached using a dicing blade. Dicing on a chip basis. Then, the expanding process which expands the space | interval of chips | tips is implemented by expanding a tape in the circumferential direction. This expanding step is performed in the subsequent pick-up step in order to improve chip recognition by a CCD camera or the like and to prevent chip breakage caused by contact between adjacent chips when picking up a chip. . Thereafter, in the pickup process, the chip is peeled off from the adhesive layer together with the adhesive layer and picked up, and directly attached to the lead frame, the package substrate, etc. in the mounting process. In this way, using a dicing die bonding tape makes it possible to directly bond a chip with an adhesive layer to a lead frame, a package substrate, etc. The step of bonding the bonding film can be omitted.

  However, in the dicing process, the semiconductor wafer and the adhesive layer are diced together using the dicing blade as described above, so that not only the cutting waste of the wafer but also the cutting waste of the adhesive layer is generated. Since the cutting waste of the adhesive layer itself has an adhesive function, if the cutting waste is clogged in the dicing groove of the wafer, the chips stick to each other, resulting in a pickup failure, and the manufacturing yield of the semiconductor device is reduced. End up.

  In order to solve the above problems, in the dicing process, only the semiconductor wafer is diced with a blade, and in the expanding process, the dicing die bonding tape is expanded to divide the adhesive layer corresponding to each chip. Has been proposed (for example, [0055] to [0056] of Patent Document 1). According to the method for dividing the adhesive layer using the tension at the time of expansion, generation of cutting waste of the adhesive is greatly suppressed, and the pickup process can be performed efficiently.

  In recent years, a so-called stealth dicing method that can cut a wafer in a non-contact manner using a laser processing apparatus has been proposed as a semiconductor wafer cutting method.

  For example, in Patent Document 2, as a stealth dicing method, a semiconductor is obtained by irradiating laser light with focused light inside a semiconductor substrate on which a sheet is attached with a die bond resin layer (adhesive layer) interposed therebetween. A step of forming a modified region by multiphoton absorption inside the substrate, forming a portion to be cut in the modified region, and expanding (expanding) the sheet so that the semiconductor substrate and the die bond resin are along the portion to be cut. A method of cutting a semiconductor substrate comprising a step of cutting a layer is disclosed.

  As another method of cutting a semiconductor wafer using a laser processing apparatus, for example, Patent Document 3 discloses a process of mounting an adhesive film (adhesive layer) for die bonding on the back surface of a semiconductor wafer, A process of attaching an extensible protective adhesive tape to the adhesive film side of the semiconductor wafer on which the adhesive film is mounted, and irradiating a laser beam along the street from the surface of the semiconductor wafer to which the protective adhesive tape is attached. The process of dividing into semiconductor chips, the process of expanding (expanding) the protective adhesive tape to give tensile force to the adhesive film, and breaking the adhesive film for each semiconductor chip, and the broken adhesive film are attached There has been proposed a semiconductor wafer dividing method including a step of removing a semiconductor chip from a protective adhesive tape.

  According to these semiconductor wafer cutting methods described in Patent Document 2 and Patent Document 3, since the semiconductor wafer is cut in a non-contact manner by laser light irradiation and tape expansion, the physical load on the semiconductor wafer is small, The semiconductor wafer can be cut without generating wafer chipping (chipping) as in the case of the current mainstream blade dicing. Moreover, since the adhesive layer is divided by the expand, cutting waste of the adhesive layer is not generated. For this reason, it attracts attention as an excellent technique that can replace blade dicing.

  When the adhesive layer is divided by an expand as described in Patent Documents 1 to 3, the dicing die bonding tape used is used to reliably cut the adhesive layer along the semiconductor chip. A uniform and isotropic expandability of the base film is required. This is because when a location where expansion is insufficient locally occurs in the base film, sufficient tensile force is not propagated to the adhesive layer at that location, and the adhesive layer cannot be divided.

  However, in general, when extruding a base film or winding a tape as a product, an anisotropic force is applied to the dicing / die bonding tape, resulting in strain stress and expansion of the base film. It is known that the property becomes uneven and anisotropic. Therefore, many proposals have been made as dicing die bonding tapes having uniform expandability (see, for example, Patent Documents 4 to 8).

However, all of the dicing die bonding tapes described in Patent Documents 4 to 8 are used for expanding for the purpose of widening the distance between the chips in order to improve the chip recognition in the pickup process. It is designed with the intention of expanding relatively slowly with a small tensile force. Therefore, when the adhesive layer is divided by the expand as described above, that is, when the expand is relatively abrupt and has a large tensile force, the expandability of the tape is not necessarily at a sufficient level.
JP 2007-5530 A JP 2003-338467 A JP 2004-273895 A JP-A-6-134941 Japanese Patent Laid-Open No. 11-199840 JP 2000-273416 A JP 2001-11207 A Japanese Patent Laid-Open No. 2003-158098

  For the above problem, it is conceivable to use a thermoplastic resin having a low Vicat softening point as a base film of a dicing die bonding tape. That is, when the back surface of the wafer is bonded to the adhesive layer of the dicing die bonding tape, heat bonding at about 70 to 80 ° C. is performed in order to heat soften the adhesive and improve the adhesiveness. By forming a tape base film using a thermoplastic resin having a low Vicat softening point below this heating temperature, the base film is softened during heat bonding, thereby producing a base film. It is possible to relieve the strain stress.

  However, when using a thermoplastic resin having a low Vicat softening point where relaxation of the strain stress of the base film can be expected as described above, the following problems occur when using the surface protection tape described above. Was found to occur.

  As described above, the dicing die bonding tape is bonded to the back surface of the wafer prior to peeling of the surface protection tape. For this reason, when using a heat-peeling type surface protection tape that is advantageous in terms of production cost compared to the energy ray curable type, the Vicat softening point of the resin constituting the base film of the dicing die bonding tape is low. When the surface protection tape is peeled off, the heat is excessively softened. As a result, the base film adheres to the suction table, making it difficult to pick up, or the base film remains on the suction table after picking up. Problems such as contaminating the table occur. In addition, the wafer is deformed when it is picked up from the suction table, and in the case of a thin wafer, there is a problem that it breaks. Even when the heating temperature at the time of peeling the surface protection tape is lower than the heating temperature at the time of bonding the wafer and the dicing die bonding tape, the heating time may be as long as about 2 minutes, for example. For this reason, there is a risk that the base film is excessively softened and a similar problem occurs.

  Therefore, the present invention does not excessively soften in the heat treatment when using a thermosetting type surface protection tape, and has a uniform and isotropic expandability that can be used in the expanding process of dividing the adhesive layer. An object of the present invention is to provide a wafer processing tape.

  A first aspect of the present invention is an expandable wafer processing tape used when dividing an adhesive layer along a chip by an expand, and a base film composed of two or more layers, It has a pressure-sensitive adhesive layer provided on a base film and an adhesive layer provided on the pressure-sensitive adhesive layer, and among the plurality of layers, the lowermost layer has a Vicat softening point defined by JIS K7206. It is made of a thermoplastic resin of 80 ° C. or higher, and at least one layer other than the lowermost layer of the plurality of layers is made of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 80 ° C. It is the tape for wafer processing characterized.

  According to a second aspect of the present invention, in the wafer processing tape according to the first aspect, at least one of the plurality of layers including at least the uppermost layer other than the lowermost layer is defined by Vicut as defined in JIS K7206. It is characterized by comprising a thermoplastic resin having a softening point of 50 ° C or higher and lower than 80 ° C.

According to a third aspect of the present invention, in the wafer processing tape according to the first or second aspect, the wafer processing tape comprises:
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., a step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) irradiating a laser beam to a portion to be divided of the semiconductor wafer to form a modified region by multiphoton absorption inside the wafer;
(F) manufacturing the semiconductor device including expanding the wafer processing tape to divide the semiconductor wafer and the adhesive layer along a dividing line to obtain a plurality of semiconductor chips with an adhesive layer. It is used for the method.

According to a fourth aspect of the present invention, in the wafer processing tape according to the first or second aspect, the wafer processing tape comprises:
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., a step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) irradiating a laser beam along a dividing line from the surface of the semiconductor wafer to divide into individual semiconductor chips;
(F) by dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape to obtain a plurality of chips with adhesive layers. It is characterized by.

According to a fifth aspect of the present invention, in the wafer processing tape according to the first or second aspect, the wafer processing tape comprises:
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., a step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) cutting the semiconductor wafer along a cutting line using a dicing blade, and cutting the semiconductor wafer into individual semiconductor chips;
(F) by dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape to obtain a plurality of chips with adhesive layers. It is characterized by.

  In the wafer processing tape of the present invention, the lowermost layer of the base film composed of a plurality of layers is formed using a thermoplastic resin having a Vicat softening point of 80 ° C. or higher. By configuring the lowermost layer with a thermoplastic resin having a high Vicat softening point in this way, it is possible to make the lowermost layer difficult to soften when the surface protective tape is heated and peeled, It is possible to suppress or prevent the occurrence of contamination and further cracking of the wafer. On the other hand, at least one layer other than the lowest layer is formed using a thermoplastic resin having a Vicat softening point of 50 ° C. or higher and lower than 80 ° C. In this way, by constituting at least one layer other than the lowermost layer with a thermoplastic resin having a relatively low Vicat softening point, when the wafer processing tape is heated and bonded to the wafer and then the surface protective tape is heated and peeled off. Since at least one layer other than the lowermost layer of the base film is softened, and as a result, the strain stress generated in the base film can be relaxed, it is possible to obtain uniform and isotropic excellent extensibility. Become. Therefore, it can be suitably used also in an expanding process for dividing an adhesive layer, which requires a large expanding speed and tensile force during expansion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a state in which a semiconductor wafer W is bonded to a wafer processing tape 10 according to an embodiment of the present invention. A surface protection tape 14 for protecting the circuit pattern is bonded to the circuit pattern forming surface (wafer surface) of the semiconductor wafer W in a back grinding process for grinding the back surface of the wafer.

The wafer processing tape 10 of the present invention is an expandable tape used when the adhesive layer is divided along the chip by expanding, and the base film 11 and the pressure-sensitive adhesive provided on the base film 11 It has a layer 12 and an adhesive layer 13 provided on the pressure-sensitive adhesive layer 12. Each layer may be cut (precut) into a predetermined shape in advance in accordance with the use process and apparatus. Furthermore, the wafer processing tape of the present invention includes a form cut for each wafer and a form obtained by winding a plurality of long sheets formed in a roll shape.
Below, the structure of each layer is demonstrated.

<Base film>
The base film 11 has a laminated structure including an uppermost layer 11a and a lowermost layer 11b having different Vicat softening points. The uppermost layer 11a is made of a thermoplastic resin having a Vicat softening point specified by JIS K7206 of 50 ° C. or higher and lower than 80 ° C., and the lowermost layer 11b is a thermoplastic having a Vicat softening point specified by JIS K7206 of 80 ° C. or higher. Consists of resin. By using the base film 11 having such a configuration, it does not excessively soften in the heat treatment when using a thermosetting type surface protection tape, and can be used in an expanding process for dividing the adhesive layer. In addition, a wafer processing tape having isotropic expandability is realized.

(Base film top layer)
As described above, the uppermost layer 11a of the base film 11 is made of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 80 ° C. When bonding the back surface of the wafer W to the adhesive layer 13 of the wafer processing tape, since heat bonding is performed at about 70 to 80 ° C. in order to heat and soften the adhesive and improve adhesiveness, By using a thermoplastic resin having a Vicat softening point of 40 ° C. or higher and lower than 70 ° C. below the heating temperature, the resin is softened at the time of heat bonding, and as a result, strain stress generated in the film is relieved. In addition, when the Vicat softening point is too low, the resin is excessively softened and fluidized at the time of the heat bonding, which is not preferable. Therefore, the lower limit of the Vicat softening point is suitably about 50 ° C.

As a thermoplastic resin which comprises the base film 11, as long as it has the said Vicat softening point, it does not specifically limit, Conventionally well-known various plastics, rubber | gum, etc. can be used. For example, ethylene- (meth) acrylic acid copolymer or ethylene-methacrylic acid-alkyl acrylate terpolymer or ionomer resin obtained by crosslinking these with metal ions, ultra-low density polyethylene, ethylene-vinyl acetate copolymer A polymer etc. are mentioned.
In the case of using a type that is cured by irradiation and whose adhesive strength is reduced as the pressure-sensitive adhesive layer 12 to be described later, the substrate film is preferably radiation transmissive.

  The thickness of the uppermost layer 11a is not particularly limited, but is preferably set to 60 to 150 μm in consideration of expandability, pickup response, strength, and the like.

(The bottom layer of the base film)
As described above, the lowermost layer 11b of the base film 11 is made of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 80 ° C. or higher. When peeling the thermosetting type surface protection tape used in the back grinding process of the wafer after bonding the wafer processing tape, the surface protection tape is used to reduce the adhesion of the surface protection tape to the wafer. Since heating is performed at a predetermined temperature for a relatively long time, by using a thermoplastic resin having a Vicat softening point of 80 ° C. or higher as the lowermost layer 11b, the lowermost layer becomes difficult to soften, and the adhesion to the adsorption table or the adsorption table It is possible to prevent the occurrence of contamination and further the cracking of the wafer.

  The upper limit of the Vicat softening point of the lowermost layer 11b is preferably about 200 ° C. from the viewpoint of facilitating surface processing such as embossing in the film forming process of the substrate.

The thermoplastic resin constituting the lowermost layer 11b is not particularly limited as long as it has the above-mentioned Vicat softening point, and various conventionally known plastics and rubbers can be used. For example, ethylene- (meth) acrylic acid copolymer or ethylene-methacrylic acid-acrylic acid alkyl ester terpolymer, low-density polyethylene, high-density polyethylene, polypropylene and the like can be mentioned.
In the case of using a type that is cured by irradiation and whose adhesive strength is reduced as the pressure-sensitive adhesive layer 12 to be described later, the substrate film is preferably radiation transmissive.

  The thickness of the uppermost layer 11a is not particularly limited, but is preferably set to 5 to 15 μm in consideration of expandability, pickup response, strength, and the like.

  In the example shown in FIG. 1, the base film 11 has a two-layer structure of an uppermost layer 11a and a lowermost layer 11b, but is not limited to this, and may have a multi-layer structure of three or more layers. . In this case, the lowermost layer is made of a thermoplastic resin having a Vicat softening point of 80 ° C. or higher, and at least one layer other than the lowermost layer is made of a thermoplastic resin having a Vicat softening point of 50 ° C. or higher and lower than 80 ° C. Thus, the same effect as that of the configuration of FIG. 1 can be obtained. In addition, it is preferable that at least one layer other than the lowermost layer composed of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 80 ° C. includes the uppermost layer.

  As a method for producing a multi-layer substrate film, a conventionally known extrusion method, laminating method, or the like can be used. When the laminating method is used, an adhesive may be interposed between the layers. A conventionally well-known adhesive agent can be used as an adhesive agent.

<Adhesive layer>
The pressure-sensitive adhesive layer 12 can be formed by applying a pressure-sensitive adhesive to the base film 11. There is no particular limitation on the pressure-sensitive adhesive layer constituting the wafer processing tape of the present invention, retainability that does not cause defects such as chip jumping with the adhesive layer during dicing, and easy peeling from the adhesive layer during pick-up It is sufficient if it has the characteristics to do. In order to improve the pickup property after dicing, the pressure-sensitive adhesive layer is preferably a radiation curable material, and is preferably a material that can be easily peeled off from the adhesive layer.

  For example, in the present invention, the compound (A) having a radiation curable carbon-carbon double bond having an iodine value of 0.5 to 20 in the molecule is selected from polyisocyanates, melamine / formaldehyde resins, and epoxy resins. It is preferable to contain a polymer obtained by subjecting at least one compound (B) to an addition reaction.

  The compound (A) that is one of the main components of the pressure-sensitive adhesive layer will be described. A preferable introduction amount of the radiation curable carbon-carbon double bond of the compound (A) is 0.5 to 20, more preferably 0.8 to 10 in terms of iodine value. If the iodine value is 0.5 or more, an effect of reducing the adhesive strength after irradiation can be obtained. If the iodine value is 20 or less, the fluidity of the adhesive after irradiation is sufficient and after stretching. Therefore, the problem that the image recognition of each element becomes difficult at the time of pick-up can be suppressed. Furthermore, the compound (A) itself is stable and easy to manufacture.

The compound (A) preferably has a glass transition point of −70 ° C. to 0 ° C., more preferably −66 ° C. to −28 ° C. When the glass transition point (hereinafter referred to as Tg) is −70 ° C. or higher, the heat resistance against heat associated with radiation irradiation is sufficient. A sufficient scattering prevention effect can be obtained.
The compound (A) may be produced by any method, and has, for example, a radiation curable carbon-carbon double bond such as an acrylic copolymer or a methacrylic copolymer, and a functional group. A compound obtained by reacting a compound having the functional group ((1)) with a compound having a functional group capable of reacting with the functional group ((2)) is used.

Among these, the compound ((1)) having the radiation curable carbon-carbon double bond and the functional group is a single compound having a radiation curable carbon-carbon double bond such as an acrylic acid alkyl ester or a methacrylic acid alkyl ester. It can be obtained by copolymerizing a monomer ((1) -1) and a monomer ((1) -2) having a functional group.
As a monomer ((1) -1), C6-C12 hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, decyl acrylate, or a single quantity of 5 or less carbon atoms The pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or methacrylates similar to these can be listed.

  Since a glass transition point becomes so low that a monomer with a large carbon number is used as a monomer ((1) -1), the thing of a desired glass transition point can be produced. In addition to the glass transition point, a monomer ((1) -1) may be blended with a low molecular compound having a carbon-carbon double bond such as vinyl acetate, styrene, acrylonitrile for the purpose of improving compatibility and various performances. ) In the range of 5% by mass or less of the total mass.

  Examples of the functional group of the monomer ((1) -2) include a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group. The monomer ((1)- Specific examples of 2) include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, glycol monoacrylates, glycol monomethacrylates. N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride, Phthalic anhydride, glycidyl acrylate And glycidyl methacrylate, allyl glycidyl ether, and those obtained by urethanizing a part of the isocyanate group of a polyisocyanate compound with a monomer having a hydroxyl group or a carboxyl group and a radiation curable carbon-carbon double bond. it can.

  In the compound (2), as the functional group used, when the functional group of the compound (1), that is, the monomer ((1) -2) is a carboxyl group or a cyclic acid anhydride group, a hydroxyl group, Examples include an epoxy group and an isocyanate group. In the case of a hydroxyl group, examples include a cyclic acid anhydride group and an isocyanate group. In the case of an amino group, examples include an epoxy group and an isocyanate group. In the case of an epoxy group, a carboxyl group, a cyclic acid anhydride group, an amino group and the like can be mentioned. Specific examples include those listed in the specific examples of the monomer ((1) -2) Can be listed.

  By leaving an unreacted functional group in the reaction between the compound (1) and the compound (2), it is possible to produce those specified in the present invention with respect to characteristics such as acid value or hydroxyl value.

  In the synthesis of the above compound (A), as the organic solvent when the reaction is carried out by solution polymerization, ketone, ester, alcohol, and aromatic solvents can be used, among which toluene, ethyl acetate , Isopropyl alcohol, benzene methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, etc., are generally good solvents for acrylic polymers and preferably have a boiling point of 60-120 ° C. The polymerization initiator is α, α′-azobisisobutyl. A radical generator such as an azobis type such as nitrile or an organic peroxide type such as benzoyl peroxide is usually used. At this time, a catalyst and a polymerization inhibitor can be used together as necessary, and the compound (A) having a desired molecular weight can be obtained by adjusting the polymerization temperature and the polymerization time. In terms of adjusting the molecular weight, it is preferable to use a mercaptan or carbon tetrachloride solvent. This reaction is not limited to solution polymerization, and other methods such as bulk polymerization and suspension polymerization may be used.

As described above, the compound (A) can be obtained. In the present invention, the molecular weight of the compound (A) is preferably about 300,000 to 1,000,000. If it is less than 300,000, the cohesive force due to radiation irradiation becomes small, and when the wafer is diced, the device is likely to be displaced, and image recognition may be difficult. In order to prevent the deviation of the element as much as possible, the molecular weight is preferably 400,000 or more. Further, if the molecular weight exceeds 1,000,000, there is a possibility of gelation at the time of synthesis and coating.
In addition, the molecular weight in this invention is a mass mean molecular weight of polystyrene conversion.

It is preferable that the compound (A) has an OH group having a hydroxyl value of 5 to 100 because the risk of pick-up mistakes can be further reduced by reducing the adhesive strength after irradiation. Moreover, it is preferable that a compound (A) has a COOH group used as the acid value of 0.5-30.
Here, if the hydroxyl value of the compound (A) is too low, the effect of reducing the adhesive strength after irradiation is not sufficient, and if it is too high, the fluidity of the adhesive after irradiation tends to be impaired. If the acid value is too low, the effect of improving the tape restoring property is not sufficient, and if it is too high, the fluidity of the pressure-sensitive adhesive tends to be impaired.

  Next, the compound (B) which is another main component of the pressure-sensitive adhesive layer will be described. The compound (B) is a compound selected from polyisocyanates, melamine / formaldehyde resins, and epoxy resins, and can be used alone or in combination of two or more. This compound (B) acts as a cross-linking agent, and the cross-linking structure formed as a result of reacting with the compound (A) or the base film causes the cohesive strength of the pressure-sensitive adhesive mainly composed of the compounds (A) and (B) to It can be improved after application.

  The polyisocyanates are not particularly limited, and examples thereof include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4 ′-[2,2-bis (4 -Phenoxyphenyl) propane] aromatic isocyanate such as diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate Lysine diisocyanate, lysine triisocyanate and the like. Specifically, Coronate L (trade name, manufactured by Nippon Polyurethane Co., Ltd.) or the like can be used.

Specific examples of the melamine / formaldehyde resin include Nicalac MX-45 (trade name, manufactured by Sanwa Chemical Co., Ltd.) and Mellan (trade name, manufactured by Hitachi Chemical Co., Ltd.).
As the epoxy resin, TETRAD-X (trade name, manufactured by Mitsubishi Chemical Corporation) or the like can be used.
In the present invention, it is particularly preferable to use polyisocyanates.

  The addition amount of (B) needs to be selected so as to be a ratio of 0.1 to 10 parts by weight, preferably 0.4 to 3 parts by weight with respect to 100 parts by weight of the compound (A). By selecting within this range, it is possible to obtain an appropriate cohesive force, and since the crosslinking reaction does not proceed abruptly, workability such as blending and application of the adhesive is improved.

Moreover, in this invention, it is preferable that the photoinitiator (C) is contained in the adhesive layer. There is no restriction | limiting in particular in the photoinitiator (C) in which an adhesive layer is contained, A conventionally well-known thing can be used. For example, benzophenones such as benzophenone, 4,4′-dimethylaminobenzophenone, 4,4′-diethylaminobenzophenone and 4,4′-dichlorobenzophenone, acetophenones such as acetophenone and diethoxyacetophenone, 2-ethylanthraquinone, t- Examples include anthraquinones such as butylanthraquinone, 2-chlorothioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzyl, 2,4,5-triarylimidazole dimer (lophine dimer), acridine compounds, and the like. These can be used alone or in combination of two or more.
As addition amount of (C), it is preferable to set it as 0.1-10 mass parts with respect to 100 mass parts of compounds (A), and it is more preferable to set it as 0.5-5 mass parts.

  Furthermore, the radiation-curable pressure-sensitive adhesive used in the present invention can be blended with a tackifier, a pressure-adjusting agent, a surfactant, or other modifiers as necessary. Moreover, you may add an inorganic compound filler suitably.

  The thickness of the pressure-sensitive adhesive layer is preferably at least 5 μm, more preferably 10 μm or more. The pressure-sensitive adhesive layer may have a structure in which a plurality of layers are laminated.

<Adhesive layer>
The adhesive layer 13 is peeled off from the adhesive layer and attached to the chip when the chip is picked up after the wafer is bonded and diced, and the adhesive for fixing the chip to the substrate or the lead frame. It is used as The adhesive layer is not particularly limited, but may be a film-like adhesive generally used for dicing die bonding tapes, such as an acrylic adhesive, epoxy resin / phenolic resin / acrylic resin. Of these, a blend-based adhesive is preferred. The thickness may be appropriately set, but is preferably about 5 to 100 μm.

  In the wafer processing tape 10 of the present invention, the adhesive layer is formed by laminating directly or indirectly a substrate film (hereinafter referred to as an adhesive film) directly or indirectly. Also good. It is preferable to apply a linear pressure of 0.01 to 10 N / m in a temperature range of 10 to 100 ° C. during laminating. In addition, the adhesive film is formed on the separator, and the separator may be peeled off after lamination, or it is used as a cover film for the adhesive tape for dicing die bonding as it is, and when bonding the wafer. It may be peeled off.

  Although an adhesive film may be laminated | stacked on the whole surface of an adhesive layer, you may laminate | stack the adhesive film cut | disconnected (pre-cut) in the shape according to the wafer previously bonded. When the adhesive film according to the wafer is laminated, as shown in FIG. 1, the adhesive layer 13 is provided at the portion where the wafer W is bonded, and the adhesive layer 13 is applied at the portion where the ring frame 12 is bonded. There is no adhesive layer 12 alone. In general, since the adhesive layer is difficult to peel off from the adherend, the ring frame can be bonded to the adhesive layer by using a pre-cut adhesive film, and it can be attached to the ring frame when peeling the tape after use. The effect that it is hard to produce the adhesive residue of is acquired.

<Application>
The usage of the wafer processing tape of the present invention is not particularly limited as long as it is used in a method for manufacturing a semiconductor manufacturing apparatus including a step of dividing an adhesive layer by at least an expand. For example, it can be suitably used in the following manufacturing methods (A) to (C) of a semiconductor manufacturing apparatus.

Manufacturing method of semiconductor manufacturing apparatus (A):
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., a step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) irradiating a laser beam to a portion to be divided of the semiconductor wafer to form a modified region by multiphoton absorption inside the wafer;
(F) manufacturing the semiconductor device including expanding the wafer processing tape to divide the semiconductor wafer and the adhesive layer along a dividing line to obtain a plurality of semiconductor chips with an adhesive layer. Method.

Semiconductor device manufacturing method (B):
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., the step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) irradiating a laser beam along a dividing line from the surface of the semiconductor wafer to divide into individual semiconductor chips;
(F) expanding the wafer processing tape to divide the adhesive layer into the semiconductor chips to obtain a plurality of chips with adhesive layers.

Manufacturing method of semiconductor manufacturing apparatus (C):
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., the step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) cutting the semiconductor wafer along a cutting line using a dicing blade, and cutting the semiconductor wafer into individual semiconductor chips;
(F) expanding the wafer processing tape to divide the adhesive layer into the semiconductor chips to obtain a plurality of chips with adhesive layers.

<How to use>
A method of using the tape when the wafer processing tape 10 of the present invention is applied to the method (A) for manufacturing a semiconductor device will be described with reference to FIGS.
First, as shown in FIG. 2, a back grinding process is performed in which a surface protection tape made of a thermosetting component is bonded to the surface of the semiconductor wafer W on which the circuit pattern is formed, and the back surface of the semiconductor wafer W is ground. .

  After completion of the back grinding process, as shown in FIG. 3, the wafer W is placed on the heater table 25 of the wafer mounter with the front side of the semiconductor wafer W facing down, and then the wafer processing tape 10 is placed on the back side of the wafer W. The adhesive layer 13 is bonded together, and the ring frame 20 is bonded to the outer peripheral portion of the pressure-sensitive adhesive layer 12. At this time, the heater table 25 is set to 70 to 80 ° C., and thus heat bonding is performed.

  Next, the wafer W to which the wafer processing tape 10 is bonded is unloaded from the heater table 25 and placed on the wafer suction table 26 with the wafer processing tape 10 side down as shown in FIG. . The protective tape 14 is heated from above the wafer W sucked and fixed to the suction table 26 by using the heating means 27 at a temperature of 50 ° C. to 80 ° C. for a heating time of 2 minutes, for example, and the adhesive strength of the protective tape 14 to the wafer W is increased. And the protective tape 14 is peeled off from the wafer surface.

  Next, as shown in FIG. 5, a laser beam is irradiated to the part to be divided of the semiconductor wafer W, thereby forming 30 modified regions by multiphoton absorption inside the wafer.

  Next, as shown in FIG. 6A, the wafer processing tape 10 to which the wafer W and the ring frame 20 are bonded is placed on the stage 21 of the expanding apparatus with the base film 11 side facing down. . In the figure, reference numeral 22 denotes a hollow cylindrical push-up member of the expanding device.

  Next, as shown in FIG. 6B, in the state where the ring frame 20 is fixed, the push-up member 22 of the expanding device is raised, and the wafer processing tape 10 is expanded. As expanding conditions, the expanding speed is, for example, 10 to 100 mm / sec, and the expanding amount (push-up amount) is, for example, 10 to 50 mm. As described above, the wafer processing tape 10 is stretched in the circumferential direction, so that the semiconductor wafer W is divided in units of chips starting from the modified region. At this time, in the adhesive layer 13, expansion (deformation) due to the expansion is suppressed in the portion bonded to the back surface of the wafer W, and no breakage occurs. On the other hand, at the position between the chips, the tension due to the expansion of the tape is not present. Concentrate and break. Therefore, the adhesive layer 13 is also divided along with the wafer W.

  Thereafter, the adhesive layer 12 is subjected to radiation curing treatment or thermosetting treatment, and the semiconductor chip C is picked up to obtain the semiconductor chip C with adhesive.

  In the method for manufacturing a semiconductor device as described above, the uppermost layer 11a having a low Vicat softening point is softened when the wafer processing tape 10 is heat bonded to the wafer W and then the surface protective tape is heated and peeled off. Since the strain stress generated in the above is relaxed, it is possible to contribute to the uniform and isotropic expandability of the wafer processing tape. Therefore, it can be suitably used even in an expand that has a rapid and large tensile force when the adhesive layer 13 is divided, and the adhesive layer can be divided well. In addition, since the lowermost layer 11b having a high Vicat softening point is difficult to soften even when the surface protection tape 14 is peeled off by heat, a thermosetting type surface protection tape that is advantageous in terms of production cost than the energy ray curing type is used. In this case, it is possible to suppress or prevent the occurrence of adhesion to the suction table, contamination of the suction table, and cracking of the wafer.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples.

(Examples 1-3, Comparative Examples 1-4)
A base film (thickness: 100 μm) having the configuration shown in Table 1 and Table 2 is prepared, an adhesive layer is applied to the base film with a thickness of 10 μm, and an adhesive layer having a thickness of 25 μm is further applied. And the tape for wafer processing of Examples 1-3 and Comparative Examples 1-4 was created. Each material described in Table 1 and Table 2 is shown below.

EMAA (1): Nucleel N1560 (ethylene-methacrylic acid copolymer) manufactured by Mitsui DuPont Vicat softening point (JIS K-7206) 60 ° C
EMAA (2): Nucleel AN4214C (ethylene-methacrylic acid copolymer Vicat softening point (JIS K-7206) 92 ° C, manufactured by Mitsui DuPont
Ionomer: Mitsui DuPont Himiran 1705 (Zinc ion crosslinked ethylene-acrylic acid copolymer) Vicat softening point (JIS K-7206) 65 ° C
LDPE: Petrocene 203 (low density polyethylene) Vicat softening point (JIS K-7206) 87 ° C

<Evaluation of presence / absence of adhesion of base resin to chuck table>
Each wafer processing tape is affixed to a dicing ring frame and adsorbed to the chuck table from the opposite side of the adhesive layer, assuming that the heat peeling type surface protection tape is peeled off at 80 ° C. for 2 minutes. After heating, the presence or absence of the base resin sticking to the chuck table was evaluated. The results are shown in Table 1 and Table 2 together.

<Evaluation of cutting performance of adhesive layer>
About the tape for wafer processing of Examples 1-3 and Comparative Examples 1-4, the evaluation test of the cutting performance of an adhesive bond layer was implemented on the conditions shown below. The case where the adhesive layer was completely divided along the chip size was regarded as a division success, and if there was even one division failure point, it was regarded as a division failure, and the success or failure of the adhesive division was evaluated. The results are shown in Table 1 and Table 2 together.
Wafer used: 100 μm silicon wafer, diameter 8 inches Wafer bonding temperature / time: 70 ° C./20 sec
Wafer cutting method: Irradiation with infrared laser along the planned cutting line Chip size: 3mm x 3mm
Expanding speed: 30mm / sec
Expanding amount: 15mm

  From Tables 1 and 2, in Comparative Examples 1 to 4, sticking to the chuck table of the base film occurred or failed to split the adhesive layer, whereas in Examples 1 to 3, As a result of achieving both of these, the effects of the present invention were confirmed.

It is sectional drawing which shows the state by which the semiconductor wafer was bonded by the tape for wafer processing concerning embodiment of this invention. It is sectional drawing which shows the state by which the tape for surface protection was bonded by the semiconductor wafer. It is a figure for demonstrating the process of bonding a semiconductor wafer and a ring frame to the tape for wafer processing. It is a figure for demonstrating the process of peeling a protective tape from the semiconductor wafer surface. It is sectional drawing which shows a mode that the modification | reformation area | region was formed in the semiconductor wafer by laser processing. (A) is sectional drawing which shows the state in which the tape for wafer processing was mounted in the expand apparatus. (B) is sectional drawing which shows the tape for wafer processing after expansion, an adhesive film, and a semiconductor wafer.

Explanation of symbols

10: Wafer processing tape 11: Base film 11a: Top layer 11b: Bottom layer 12: Adhesive layer 13: Adhesive layer 14: Surface protection film 20: Ring frame 21: Stage 22: Push-up member 25: Heater table 26 : Suction table 27: Heating means

Claims (5)

An expandable wafer processing tape used when dividing an adhesive layer along a chip by expanding,
A base film composed of two or more layers,
An adhesive layer provided on the base film;
An adhesive layer provided on the pressure-sensitive adhesive layer,
Of the plurality of layers, the lowermost layer is made of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 80 ° C. or higher.
Of the plurality of layers, at least one layer other than the lowermost layer is made of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 50 ° C or higher and lower than 80 ° C.   The at least one layer including at least the uppermost layer other than the lowermost layer among the plurality of layers is made of a thermoplastic resin having a Vicat softening point defined by JIS K7206 of 50 ° C or higher and lower than 80 ° C. 2. The wafer processing tape according to 1. The wafer processing tape is
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., a step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) irradiating a laser beam to a portion to be divided of the semiconductor wafer to form a modified region by multiphoton absorption inside the wafer;
(F) manufacturing the semiconductor device including expanding the wafer processing tape to divide the semiconductor wafer and the adhesive layer along a dividing line to obtain a plurality of semiconductor chips with an adhesive layer. The wafer processing tape according to claim 1, wherein the tape is used in a method. The wafer processing tape is
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., the step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) irradiating a laser beam along a dividing line from the surface of the semiconductor wafer to divide into individual semiconductor chips;
(F) by dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape to obtain a plurality of chips with adhesive layers. The wafer processing tape according to claim 1, wherein the tape is for wafer processing. The wafer processing tape is
(A) a step of bonding a surface protection tape to the surface of the semiconductor wafer on which the circuit pattern is formed;
(B) a back grinding process for grinding the back surface of the semiconductor wafer;
(C) In a state where the semiconductor wafer is heated at 70 to 80 ° C., the step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor wafer;
(D) heating the surface protection tape and peeling the surface protection tape from the semiconductor wafer surface;
(E) cutting the semiconductor wafer along a cutting line using a dicing blade, and cutting the semiconductor wafer into individual semiconductor chips;
(F) by dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape to obtain a plurality of chips with adhesive layers. The wafer processing tape according to claim 1, wherein the tape is for wafer processing.

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