JP5554118B2 - Wafer processing tape - Google Patents

Description

  TECHNICAL FIELD 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 an ultraviolet irradiation treatment when the surface protective tape is made of an energy ray curable component such as ultraviolet rays, and when the surface protective tape is made of a thermosetting component, heat treatment is performed. Irradiation (heating) treatment.

  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. Thereafter, an expanding process is performed to expand the distance between the chips by expanding the tape in the radial direction of the semiconductor wafer. 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, no cutting waste of the adhesive is generated, and there is no adverse effect in the pickup process.

  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 9).

  In addition, since the tape is slack after the expansion, the intervals between the individual chips cannot be stably maintained, and there is a problem that the adhesive layer re-adheses due to contact between adjacent chips during conveyance. In order to solve this problem, a method has been proposed in which the tape is a heat-shrinkable tape, and the tape is heated and tensioned after the dividing step to maintain the interval between chips (for example, see Patent Documents 10 and 11). ). As the heat shrinkable tape, a polyvinyl chloride tape is desirable (for example, see Patent Document 10 [0008]). However, when the above-mentioned polyvinyl chloride tape is incinerated after use, dioxins and chlorinated aromatic hydrocarbons, which are analogs thereof, may be generated and may cause a burden on the environment.

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 JP 2009-231699 A JP 2002-334852 A JP 2007-27562 A

  As described above, according to the method of using a heat-shrinkable tape and heating and tensioning the tape after the dividing step to maintain the space between the chips, the adhesive layer is reattached due to the looseness of the tape after expansion. Can be prevented. However, depending on the performance of the heat-shrinkable tape used, shrinkage due to heating may not be sufficient, and slack will remain after the heat-shrink process, stabilizing the separated semiconductor chip and the separated adhesive layer on the tape In some cases, the yield of the semiconductor component manufacturing process may deteriorate due to contact between adjacent semiconductor chips and damage, or contact between adhesive layers and re-adhesion. .

  The present invention has a uniform expandability suitable for the process of dividing the adhesive layer by the expand, shows sufficient shrinkage in the heat shrinking process, and does not cause defects due to loosening after the heat shrinking process. The purpose is to provide a tape.

In order to solve the above problems, the first aspect of the present invention provides:
An expandable wafer processing tape used when dividing an adhesive layer along a chip by expanding,
Having a base film and an adhesive layer provided on the base film,
The base film is composed of a single layer of a thermoplastic crosslinked resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 90 ° C.,
The thermoplastic crosslinked resin is an ionomer resin obtained by crosslinking an ethylene- (meth) acrylic acid binary copolymer with zinc ions, or an ethylene- (meth) acrylic acid- (meth) acrylic acid alkyl ester ternary. It is an ionomer resin obtained by crosslinking a copolymer with zinc ions, and the mass ratio of the ethylene component in the copolymer is 80 to 95%, and the mass ratio of the total component of the acrylic acid component or the alkyl acrylate ester component is 5 to 20%. And the zinc ion content in the base film is 2 to 4% by mass,
The increase in stress due to heat shrinkage is 9 MPa or more.
The second aspect of the present invention is characterized in that an adhesive layer is laminated on the pressure-sensitive adhesive layer.

  According to the wafer processing tape of the first and second aspects, the base film is made of a thermoplastic cross-linked resin having a Vicat softening point of 50 ° C. or higher and lower than 90 ° C., and the increase in stress due to heat shrinkage is 9 MPa or higher. Therefore, the tape for wafer processing has uniform expandability suitable for the process of dividing the adhesive layer by the expand, exhibits sufficient contractibility in the heat shrinking process, and does not cause problems due to looseness after the heat shrinking process. It can be.

  That is, in the non-crosslinked resin, the extensibility becomes anisotropic because the molecular chains are oriented in the processing direction, but if the intermolecular chains are cross-linked, the extensibility becomes more isotropic and the adhesive layer It can be suitably used also in the expanding process for splitting. In addition, when a certain level of elongation strain is applied to a film made of a cross-linked resin, the non-crosslinked portion yields, while stress is stored at the cross-linking point. Therefore, if the non-cross-linked portion is softened by heating, it is stored at the cross-linking point. A restoring force acts on the base film by the applied stress. In general, the expansion rate of the wafer processing tape in the expanding process is about 10%. However, when an elongation strain of 10% is applied to a film made of a general non-crosslinked resin such as polyethylene, it yields and heats up. However, the crosslinked resin film is easily shrunk and restored by being heated to a temperature near or above the softening point.

  In general, in the heating step after the expanding step, the temperature of the wafer processing tape is about 50 to 90 ° C. by heating using a hot air blower or the like. Therefore, the base film resin of the wafer processing tape is JIS K7206. A Vicat softening point defined by is suitable to be 50 ° C. or higher and lower than 90 ° C., more preferably 50 ° C. or higher and lower than 80 ° C. If the Vicat softening point is too low, the resin is excessively softened and fluidized during the heat shrinkage, which is not preferable. When the base material of the wafer processing tape is fluidized in the heat shrinking process, the wafer processing tape is melted. Therefore, the lower limit of the Vicat softening point is suitably about 50 ° C. For the above reasons, by using a thermoplastic cross-linked resin having a Vicat softening point of 50 ° C. or higher and lower than 90 ° C. for the base film, it has a uniform expandability suitable for the step of dividing the adhesive layer by expanding, and Thus, a wafer processing tape exhibiting sufficient shrinkage in the heat shrinking step can be obtained.

  In addition, if the wafer is not a wafer processing tape whose shrinkage stress increases more than a certain level after heating, after adding about 10% elongation corresponding to the expansion rate of the wafer processing tape in the general expanding process, It is not easy to sufficiently remove the slack of the wafer processing tape. If the slack cannot be removed sufficiently, the divided semiconductor chip and the separated adhesive cannot be stably fixed on the wafer processing tape, and the adjacent chips are damaged due to contact with each other or bonded. When the agent layers come into contact with each other and re-adhere, the yield of the semiconductor component manufacturing process deteriorates.

  The stress acting on the wafer processing tape during heat shrinkage is determined by the method defined in JIS K7162, and after applying 10% elongation strain to the wafer processing tape test piece, the distance between chucks is kept constant. The test piece in the process of heating until the temperature of the test piece reaches 70 ° C. while maintaining the state, maintaining the test piece at a temperature of 70 ° C. for 1 minute, and then returning the test piece to room temperature The maximum heat shrinkage stress is preferably 9 MPa or more, more preferably 10 MPa or more than the initial stress immediately before the start of heating. In the case of a wafer processing tape using a base film in which the increase in stress due to the heat shrinkage is less than 9 MPa, the contraction stress is offset by the expansion stress caused by the weight of the semiconductor wafer or the wafer processing tape. The slack cannot be removed sufficiently even by heating. For the above reasons, by using a thermoplastic cross-linked resin whose stress increase due to heat shrinkage is 9 MPa or more for the base film, it is possible to obtain a wafer processing tape that does not cause problems due to loosening after the heat shrinking step. .

According to a third aspect of the present invention, in the wafer processing tape according to the first or second aspect, a chlorine atom content of the thermoplastic crosslinked resin is less than 1% by mass.

According to the wafer processing tape of the third aspect, since chlorine is not contained in the structural unit of the molecular chain, it is possible to provide a wafer processing tape with a low environmental load while solving the above-mentioned problems.

According to a fourth aspect of the present invention, in the wafer processing tape according to the second or third 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 to 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) 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) 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 the adhesive layer;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
It is used for the manufacturing method of the semiconductor device containing this.

According to a fifth aspect of the present invention, in the wafer processing tape according to the second or third 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 to 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) 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) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) The step of removing the slack generated in the expanding step by heating and shrinking the portion of the wafer processing tape that does not overlap the semiconductor chip to maintain the interval between the semiconductor chips. Picking up the attached semiconductor chip from the adhesive layer of the wafer processing tape;
It is used for the manufacturing method of the semiconductor device containing this.

According to a sixth aspect of the present invention, in the wafer processing tape according to the second or third 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 to 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) 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) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
It is used for the manufacturing method of the semiconductor device containing this.

According to a seventh aspect of the present invention, in the wafer processing tape according to the second or third aspect, the wafer processing tape comprises:
(A) A semiconductor wafer on which a circuit pattern is formed using a dicing blade is cut to a depth less than the thickness of the wafer along a predetermined cutting line.
(B) bonding a surface protection tape to the surface of the semiconductor wafer;
(C) a back grinding process in which the back surface of the semiconductor wafer is ground and divided into individual semiconductor chips;
(D) A step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor chip in a state where the semiconductor wafer is heated to 70 to 80 ° C .;
(E) peeling the surface protection tape from the semiconductor wafer surface;
(F) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
It is used for the manufacturing method of the semiconductor device containing this.

  In the wafer processing tape of the present invention, the base film is made of a thermoplastic crosslinked resin having a Vicat softening point of 50 ° C. or higher and lower than 90 ° C., and the increase in stress due to thermal shrinkage is 9 MPa or higher. It is possible to obtain a tape for wafer processing that has a uniform expandability suitable for the process of dividing the film, exhibits sufficient shrinkage in the heat shrinking process, and does not cause defects due to slack after the heat shrinking process.

  In other words, the Vicat softening point is a thermoplastic cross-linked resin having a softening point of 50 ° C. or higher and lower than 90 ° C., so that it has uniform expandability suitable for the process of dividing the adhesive layer by the expand and has sufficient shrinkage in the heat shrinking process. It can be set as the tape for wafer processing which shows property. Moreover, since the increase in stress due to thermal shrinkage is 9 MPa or more, a wafer processing tape that does not cause problems due to looseness after the heat shrinkage step can be obtained.

It is sectional drawing which shows the state by which the tape for wafer processing concerning Embodiment of this invention and the surface protection tape were bonded to the semiconductor wafer. It is sectional drawing which shows the state by which the tape for surface protection was bonded by the semiconductor wafer. It is sectional drawing for demonstrating the process of bonding a semiconductor wafer and a ring frame to the tape for wafer processing. It is sectional drawing for demonstrating the process of peeling a surface protection tape from the surface of a semiconductor wafer. It is sectional drawing which shows a mode that the modification | reformation area | region was formed in the semiconductor wafer by laser processing. (A) It is sectional drawing which shows the state in which the tape for wafer processing was mounted in the expand apparatus. (B) It is sectional drawing which shows the tape for wafer processing after expansion, an adhesive bond layer, and a semiconductor wafer. It is sectional drawing for demonstrating the process of removing the slack of a tape by heat shrink. It is sectional drawing for demonstrating the process of picking up the semiconductor chip with an adhesive layer from the surface of the adhesive layer of the tape for wafer processing. It is sectional drawing for demonstrating the measuring method of slack amount.

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. A wafer processing tape 10 is bonded to the back surface of the semiconductor wafer W. The wafer processing tape 10 of the present invention is an expandable tape used when the adhesive layer 13 is divided along the chip by expanding. The wafer processing tape 10 includes a base film 11, a pressure-sensitive adhesive layer 12 provided on the base film 11, and an adhesive layer 13 provided on the pressure-sensitive adhesive layer 12. The back surface of the semiconductor wafer W is bonded onto the substrate 13. Each layer may be cut (precut) into a predetermined shape in advance according to the use process and the 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 is composed of a thermoplastic crosslinked resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 90 ° C. By using the base film 11 having such a configuration, it is possible to realize the wafer processing tape 10 having uniform and isotropic expandability that can be used in the expanding process of dividing the adhesive layer 13. In addition, since the cross-linked resin has a higher restoring force against tension compared to the non-cross-linked resin, the shrinkage stress when the resin is softened by applying heat to the stretched state after the expanding process is large, and the tape after the expanding process. It is possible to remove the slack caused by the heat shrinkage, and to keep the interval between the individual semiconductor chips stably by tensioning the tape. In general, in the heating step after the expanding step, the tape is about 50 to 90 ° C., so if the softening point is too higher than this range, it is difficult to sufficiently remove the slack, and conversely if the tape is too low, the tape Risk of fusing.

  The thermoplastic cross-linked resin may be anything as long as the Vicat softening point specified by JIS K7206 is 50 ° C. or higher and lower than 90 ° C., but ethylene- (meth) acrylic acid binary copolymer or ethylene- (meta ) Acrylic acid-An ionomer resin obtained by crosslinking (meth) acrylic acid with metal ions is suitable for the expanding process in terms of uniform expandability, and has a strong restoring force when heated by crosslinking. It is also particularly suitable for the step of removing slack. In addition, since the ionomer resin does not contain chlorine in the structure of the molecular chain, it does not generate chlorinated aromatic hydrocarbons with dioxins and their analogs, even after disposal of tape that is no longer needed after use. Environmental impact is also small. The metal ion contained in the ionomer resin may be anything, but zinc ion is particularly preferred from the viewpoint of low elution and particularly low contamination.

  As the thermoplastic crosslinked resin, in addition to the ionomer resin, a low density polyethylene having a specific gravity of 0.910 or more and less than 0.930 or an ultra low density polyethylene having a specific gravity of less than 0.910 was crosslinked by irradiating with an electron beam. Those are also suitable. This thermoplastic cross-linked resin is suitable for the above-mentioned expanding process because it has a certain level of expandability because the cross-linked part and non-cross-linked part coexist in the resin. It is also particularly suitable for the step of removing the slack of the tape generated in step 1. A resin having a Vicat softening point of 50 ° C. or higher and lower than 90 ° C. and sufficient uniform expandability can be obtained by appropriately adjusting the amount of electron beam irradiated to the low density polyethylene or the ultra low density polyethylene. In addition, since the above electron beam cross-linked polyethylene does not contain chlorine in the structure of the molecular chain, chlorinated aromatic hydrocarbons with dioxins and their analogs are not removed even after disposal of tapes that are no longer needed after use. Environmental impact is small because it is not generated. An example of the low-density polyethylene or ultra-low-density polyethylene is a kernel manufactured by Nippon Polychem.

  As the thermoplastic cross-linked resin, in addition to the ionomer resin and the electron beam cross-linked polyethylene, those obtained by irradiating an ethylene-vinyl acetate copolymer with an electron beam are also suitable. This thermoplastic cross-linked resin is particularly suitable in the step of removing slack of the tape generated in the expanding step because it has a strong restoring force when heated. By appropriately adjusting the amount of the electron beam, a resin having a Vicat softening point of 50 ° C. or higher and lower than 90 ° C. and sufficient uniform expandability can be obtained. The electron beam cross-linked ethylene-vinyl acetate copolymer does not contain chlorine in the structure of the molecular chain, so chlorination with dioxin and its analogs is possible even after disposal of the tape that is no longer needed after use. Because it does not generate aromatic hydrocarbons, the environmental impact is small. An example of the ethylene-vinyl acetate copolymer is Ultracene manufactured by Nippon Polychem.

  In addition, in the example shown in FIG. 1, although the base film 11 is a single layer, it is not limited to this, The 2 or more types of Vicat softening points were laminated | stacked 2 or more thermoplastic thermoplastic resin below 90 degreeC. A multi-layer structure having more than one layer may be used. The thickness of the base film 11 is not particularly specified, but it is preferably about 50 to 200 um, more preferably 100 um to 150 um, as the thickness that is easily stretched in the expansion process of the wafer processing tape 10 and has sufficient strength not to break. .

  As a method for producing the multi-layer base film 11, 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. The pressure-sensitive adhesive layer 12 that constitutes the wafer processing tape 10 of the present invention is not particularly limited, and retainability to such an extent that it does not peel off from the adhesive layer 13 during dicing and does not cause defects such as chip skipping, or during pickup. In this case, any material may be used as long as it has a property that facilitates peeling from the adhesive layer 13. In order to improve the pick-up property after dicing, the pressure-sensitive adhesive layer 12 is preferably an energy ray-curable material, and is preferably a material that can be easily separated from the adhesive layer 13 after curing.

  For example, in the present invention, the compound (A) having an energy ray-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. Here, the energy rays are light rays such as ultraviolet rays or ionizing radiations such as electron beams.

  The compound (A) that is one of the main components of the pressure-sensitive adhesive layer 12 will be described. A preferable introduction amount of the energy ray-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 with energy rays can be obtained. If the iodine value is 20 or less, the fluidity of the adhesive after irradiation with energy rays is sufficient, Since a sufficient gap between the chips after expansion of the wafer processing tape 10 can be obtained, the problem that it is difficult to recognize the image of each chip during 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. If the glass transition point is −70 ° C. or higher, the heat resistance against the heat accompanying energy beam irradiation is sufficient, and if it is 0 ° C. or lower, the effect of preventing scattering of semiconductor chips after dicing on a wafer having a rough surface is sufficient. can get. The above compound (A) may be produced by any method, for example, a mixture of an acrylic copolymer and a compound having an energy ray-curable carbon-carbon double bond, or a functional group. An acrylic copolymer or a methacrylic copolymer (A1) having a functional group, and a compound (A2) having a functional group capable of reacting with the functional group and having an energy ray-curable carbon-carbon double bond ) Is used.

  Among these, the compound (A1) having the functional group includes an energy ray-curable carbon-carbon double bond monomer (A1-1) such as an alkyl acrylate ester or an alkyl methacrylate ester, and an energy ray. It can be obtained by copolymerizing a monomer (A1-2) having a curable carbon-carbon double bond and having a functional group. As the monomer (A1-1), hexyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, decyl acrylate, or alkyl chain having 6 to 12 carbon atoms in the alkyl chain. Pentyl acrylate, n-butyl acrylate, isobutyl acrylate, ethyl acrylate, methyl acrylate, or a similar methacrylate, etc., can be listed.

  Since a glass transition point becomes so low that a monomer with a large carbon number is used as the monomer (A1-1), a monomer having a desired glass transition point can be produced. In addition to the glass transition point, it is also possible to blend 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 of the monomer (A1-1). It is possible within the range of 5% by mass or less of the total mass.

  Examples of the functional group of the monomer (A1-2) include a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, and an isocyanate group. Specific examples of the monomer (A1-2) Examples include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, glycol monoacrylates, glycol monomethacrylates, N-methylol Acrylamide, N-methylol methacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride, phthalic anhydride, Glycidyl relay , Glycidyl methacrylate, allyl glycidyl ether, and those obtained by urethanizing a part of the isocyanate group of the polyisocyanate compound with a monomer having a hydroxyl group or a carboxyl group and an energy ray-curable carbon-carbon double bond. .

  In the compound (A2), the functional group used is a hydroxyl group or an epoxy group when the functional group of the compound (A1), that is, the monomer (A1-2) is a carboxyl group or a cyclic acid anhydride group. In the case of a hydroxyl group, a cyclic acid anhydride group and an isocyanate group can be mentioned. In the case of an amino group, an epoxy group and an isocyanate group can be mentioned. In the case of an epoxy group, a carboxyl group, a cyclic acid anhydride group, an amino group, and the like can be exemplified. Specific examples thereof are the same as those listed in the specific examples of the monomer (A1-2). Can be enumerated.

  In the reaction of the compound (A1) and the compound (A2), by leaving an unreacted functional group, what is prescribed in the present invention can be produced 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 becomes small, and when the wafer is diced, chip displacement tends to occur, and image recognition may be difficult. In order to prevent this chip displacement 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 energy beam 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 with energy rays is not sufficient, and if it is too high, the fluidity of the adhesive after irradiation with energy rays 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.) can be used. That. 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 mass, preferably 0.4 to 3 parts by mass with respect to 100 parts by mass 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.

  In the present invention, the pressure-sensitive adhesive layer 12 preferably contains a photopolymerization initiator (C). There is no restriction | limiting in particular in the photoinitiator (C) contained in the adhesive layer 12, 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-triallylimidazole dimer (rophine dimer), and acridine compounds. 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 energy ray-curable pressure-sensitive adhesive used in the present invention may contain a tackifier, a tackifier, a surfactant, or other modifiers as necessary. Moreover, you may add an inorganic compound filler suitably.

  The thickness of the pressure-sensitive adhesive layer 12 is preferably at least 5 μm, more preferably 10 μm or more. The pressure-sensitive adhesive layer may have a configuration in which a plurality of layers are laminated, and the composition of each layer may be the same or different.

<Adhesive layer>
When the chip is picked up after the semiconductor wafer is bonded and diced, the adhesive layer 13 is peeled off from the pressure-sensitive adhesive layer 12 and attached to the chip. When the chip is fixed to the substrate or the lead frame, It is used as an adhesive. When processing a semiconductor wafer, the adhesive layer 13 may be preliminarily laminated on a wafer processing tape 10 in which an adhesive layer 12 is laminated on a base film 11, or may be separately bonded to a semiconductor wafer. . The adhesive is not particularly limited, but may be a film adhesive generally used for dicing and die bonding tapes, such as acrylic adhesive, epoxy resin / phenolic resin / acrylic resin. A blended 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 13 is obtained by laminating the adhesive layer 13 in advance (hereinafter referred to as an adhesive film) directly or indirectly on the base film 11. It may be formed. 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. It is assumed that the adhesive layer 13 is formed on the separator, and the separator may be peeled off after the lamination, or it is used as it is as a cover film of the wafer processing tape 10 and the semiconductor wafer is bonded. You may peel off.

  Although an adhesive film may be laminated | stacked on the whole surface of the adhesive layer 12, you may laminate | stack the adhesive film cut | disconnected (pre-cut) in the shape according to the semiconductor wafer bonded beforehand. When the adhesive film according to the semiconductor wafer is laminated, as shown in FIG. 1, the adhesive layer 13 is provided in the portion where the semiconductor wafer W is bonded, and the adhesive is applied in the portion where the ring frame 20 is bonded. There is no layer 13 and only the adhesive layer 12 is present. In general, since the adhesive layer 13 is difficult to peel off from the adherend, the ring frame 20 can be bonded to the pressure-sensitive adhesive layer 12 by using a pre-cut adhesive film, and the ring is peeled off when the tape is peeled off after use. The effect that the adhesive residue to the frame 20 hardly occurs is obtained.

<Application>
The usage of the wafer processing tape 10 of the present invention is not particularly limited as long as it is used in a method for manufacturing a semiconductor device including a step of dividing the adhesive layer 13 by at least an expand. For example, it can be suitably used in the following semiconductor device manufacturing methods (A) to (D).

Manufacturing method of semiconductor device (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 to 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) 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) 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 the adhesive layer;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from the adhesive layer of the wafer processing tape;
A method of manufacturing a semiconductor device including:

Manufacturing method of semiconductor device (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 to 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) 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) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from the adhesive layer of the wafer processing tape;
A method of manufacturing a semiconductor device including:

Manufacturing method of semiconductor device (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 to 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) 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) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from the adhesive layer of the wafer processing tape;
A method of manufacturing a semiconductor device including:

Manufacturing method of semiconductor device (D)
(A) A semiconductor wafer on which a circuit pattern is formed using a dicing blade is cut to a depth less than the thickness of the wafer along a predetermined cutting line.
(B) bonding a surface protection tape to the surface of the semiconductor wafer;
(C) a back grinding process in which the back surface of the semiconductor wafer is ground and divided into individual semiconductor chips;
(D) A step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor chip in a state where the semiconductor wafer is heated to 70 to 80 ° C .;
(E) peeling the surface protection tape from the semiconductor wafer surface;
(F) expanding the wafer processing tape to divide the adhesive layer for each semiconductor chip to obtain a plurality of semiconductor chips with the adhesive layer; and (g) the wafer processing tape. Removing the slack generated in the expanding step by heating and shrinking a portion that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from the adhesive layer of the wafer processing tape;
A method of manufacturing a semiconductor device including:

  In addition, the manufacturing method (A) to (D) of the semiconductor device is a manufacturing method in the case of using a tape for wafer processing having a base film, an adhesive layer, and an adhesive layer. When the wafer processing tape has only the base film and the pressure-sensitive adhesive layer, the wafer processing tape is attached to the back surface of the semiconductor wafer via the adhesive layer in the step of bonding the wafer processing tape to the semiconductor wafer. Make sure to paste.

<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 14 made of an ultraviolet curable component is bonded to the surface of a semiconductor wafer W on which a circuit pattern is formed, and the back surface of the semiconductor wafer W is ground. To do.

  After completion of the back grinding process, as shown in FIG. 3, the semiconductor 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 is performed on the back side of the semiconductor wafer W. The tape 10 is bonded. The wafer processing tape 10 used here is obtained by laminating a pre-cut (pre-cut) adhesive film into a shape corresponding to the semiconductor wafer W to be bonded, and on the surface to be bonded to the semiconductor wafer W. The area where the adhesive layer 12 is exposed is provided around the area where the adhesive layer 13 is exposed. The portion of the wafer processing tape 10 where the adhesive layer 13 is exposed and the back surface of the semiconductor wafer W are bonded together, and the portion where the adhesive layer 12 around the adhesive layer 13 is exposed and the ring frame 20 are bonded together. At this time, the heater table 25 is set to 70 to 80 ° C., and thus heat bonding is performed.

Next, the semiconductor wafer W bonded with the wafer processing tape 10 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. To do. Then, from the upper side of the semiconductor wafer W sucked and fixed to the suction table 26, for example, an ultraviolet light source 27 is used to irradiate the substrate surface side of the surface protective tape 14 with 1000 mJ / cm ² of ultraviolet light. The adhesive strength to the wafer W is reduced, and the surface protection tape 14 is peeled off from the surface of the semiconductor wafer W.

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

  Next, as shown in FIG. 6A, the wafer processing tape 10 on which the semiconductor 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. To do. 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 the expanding condition, the expanding speed is, for example, 10 to 500 mm / sec, and the expanding amount (push-up amount) is, for example, 5 to 25 mm. As described above, the wafer processing tape 10 is stretched in the radial direction of the semiconductor wafer W, so that the semiconductor wafer W is divided into chips from the modified region 30 as a starting point. At this time, the adhesive layer 13 is not stretched by deformation (deformation) at the portion bonded to the back surface of the semiconductor wafer W and does not break, but at the position between the chips C, the tension due to the tape expand is not present. Concentrate and break. Therefore, the adhesive layer 13 is also divided along with the semiconductor wafer W. Thereby, a plurality of semiconductor chips C to which the adhesive layer 13 is attached can be obtained.

  Next, as shown in FIG. 7, a step of returning the push-up member 22 to the original position, removing the slack of the wafer processing tape 10 generated in the previous expanding step, and maintaining the interval between the semiconductor chips C stably. Do. In this step, for example, hot air of 50 to 90 ° C. is applied to the annular region 28 between the region of the wafer processing tape 10 where the semiconductor chip C exists and the ring frame 20 using the hot air nozzle 29. The base film 11 is heated and shrunk to tension the wafer processing tape 10. Thereafter, the pressure-sensitive adhesive layer 12 is subjected to an energy ray curing process or a thermosetting process, and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer 12 to the adhesive layer 13 is weakened. Then, as shown in FIG. 8, the semiconductor chip C is picked up by picking up the semiconductor chip C from the back surface of the base film 11 (surface on which the semiconductor wafer is not bonded) with the push-up pins 41 and sucking it by the suction collet 42. .

  In the method for manufacturing a semiconductor device as described above, the base film 11 made of a thermoplastic crosslinked resin has a large restoring force against tension applied at the time of expansion and has a low Vicat softening point, and thus easily contracts by heating. Therefore, the present invention can be suitably applied to the process of removing the slack generated in the wafer processing tape 10 after the expanding process of dividing the adhesive layer 13 by heat shrinkage and tensioning the tape.

  Next, examples and comparative examples performed for clarifying the effects of the present invention will be described in detail, but the present invention is not limited to these examples.

The tapes 10 for wafer processing of Examples 1-2 , Reference Examples 3-5, and Comparative Examples 1-7 use the base film 11 shown in Table 1 and Table 2, respectively. The pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 12, the adhesive composition constituting the adhesive layer 13, and the method for producing the wafer processing tape 10 are the same. In the following description, the density was measured by JIS K7112, and the melting point was measured by DSC (differential scanning calorimetry).

(1) Sample preparation (1.1) Example 1
(Preparation of base film 11)
Zinc ionomer a (density 0.96 g / cm ³ , zinc ion content 4 mass) of ethylene-methacrylic acid-ethyl methacrylate (mass ratio 8: 1: 1) terpolymer synthesized by radical polymerization method %, Chlorine content of less than 1% by mass, Vicat softening point 56 ° C., melting point 86 ° C.) are melted at 140 ° C. and formed into a long film of 100 μm thickness using an extruder. The support base material 1 which makes the material film 11 was produced.

(Preparation of adhesive composition 1)
Acrylic copolymer (molecular weight 600,000, hydroxyl value 4.7 mgKOH / g, acid value 0.2 mgKOH / g) was obtained by radical polymerization of butyl acrylate, 2-hydroxyethyl acrylate and acrylic acid. To 100 parts by mass of this acrylic copolymer, 30 parts by mass of trimethylolpropane triacrylate was added as a photopolymerizable cured product, and 2 parts by mass of Coronate L (manufactured by Nippon Polyurethane) was added as a polyisocyanate, and photopolymerization was started. A mixture obtained by adding 1 part by mass of Irgacure 184 (manufactured by Ciba Geigy Co., Ltd.) as an agent was dissolved in ethyl acetate and stirred to prepare an adhesive composition 1.

(Preparation of adhesive composition 1)
50 parts by mass of a cresol novolac type epoxy resin (epoxy equivalent 197, molecular weight 1200, softening point 70 ° C.) as an epoxy resin, 1.5 parts by mass of γ-mercaptopropyltrimethoxysilane as a silane coupling agent, γ-ureidopropyltriethoxysilane Cyclohexanone was added to a composition comprising 3 parts by mass and 30 parts by mass of silica filler having an average particle size of 16 nm, and the mixture was stirred and mixed, and further kneaded for 90 minutes using a bead mill. To this, 100 parts by mass of acrylic resin (molecular weight 200,000, hydroxyl value 3.5 mgKOH / g) synthesized by radical polymerization of butyl acrylate and 2-hydroxyethyl acrylate, 1 part by mass of Coronate L as a curing agent, An adhesive composition 1 was prepared by stirring and mixing.

(Preparation of wafer processing tape 10)
The pressure-sensitive adhesive composition 1 is coated on the supporting base material 1 forming the base film 11 so that the thickness after drying is 20 μm, and dried at 110 ° C. for 3 minutes to adhere to the base film 11. A pressure-sensitive adhesive sheet on which the agent layer 12 was formed was prepared. Separately, a release liner made of a polyethylene-terephthalate film obtained by releasing the adhesive composition 1 was coated so that the thickness after drying was 20 μm, and dried at 110 ° C. for 3 minutes to release the release liner. An adhesive film having the adhesive layer 13 formed thereon was produced.

  Next, the adhesive sheet was cut into the shape shown in FIG. 3 and the like that can be bonded to the ring frame 20 so as to cover the opening. Further, the adhesive film was cut into the shape shown in FIG. 3 and the like that can cover the back surface of the semiconductor wafer W. And the part which the adhesive layer 12 exposes to the circumference | surroundings of an adhesive film as shown in FIG. 3 etc. is formed in the adhesive layer 12 side of the said adhesive sheet, and the adhesive layer 13 side of the said adhesive film. The wafer processing tape 10 was prepared by bonding to each other. In this way, the wafer processing tape 10 in which the supporting base material forming the base film 11, the energy ray curable pressure-sensitive adhesive layer 12, and the adhesive layer 13 were laminated in this order was prepared. It was.

(1.2) Example 2
(Preparation of base film 11)
Zinc ionomer b (density 0.95 g / cm ³ , zinc ion content 2 mass%, chlorine) of ethylene-methacrylic acid (mass ratio 9.5: 0.5) binary copolymer synthesized by radical polymerization method By melting resin beads having a content of less than 1% by mass, Vicat softening point 81 ° C., melting point 100 ° C. at 140 ° C., and forming into a long film having a thickness of 100 μm using an extruder, the base film 11 The support base material 2 which makes | forms was produced.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 by using the supporting base material 2 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1, and this was used as Example 2. A sample was used.

(1.3) Reference Example 3
(Preparation of base film 11)
Resin beads of ultra-low density polyethylene ULDPEa (density 0.90 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 72 ° C., melting point 90 ° C.) synthesized by metallocene polymerization method are melted at 140 ° C. and extruded. After forming into a 100 μm-thick long film using a machine, a support substrate forming the base film 11 is irradiated with an electron beam at an acceleration voltage of 1 MeV and an irradiation amount of 20 Mrad using a medium energy electron beam accelerator. Material 3 was produced.

A supporting substrate 3 forming the base film 11, the pressure-sensitive adhesive composition 1, using the adhesive composition 1 to prepare a wafer processing tape 10 in the same manner as in Example 1, which in Reference Example 3 A sample was used.

(1.4) Reference example 4
(Preparation of base film 11)
Low density polyethylene LDPEb (density 0.91 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 81 ° C., melting point 102 ° C.) synthesized by metallocene polymerization method is melted at 140 ° C. Is formed into a long film shape having a thickness of 100 μm, and then irradiated with an electron beam at an acceleration voltage of 1 MeV and an irradiation amount of 20 Mrad using a medium energy electron beam accelerator, thereby forming a base film 11. 4 was produced.

A support base material 4 constituting the base material film 11, the pressure-sensitive adhesive composition 1, using the adhesive composition 1 to prepare a wafer processing tape 10 in the same manner as in Example 1, which in Reference Example 4 A sample was used.

(1.5) Reference Example 5
(Preparation of base film 11)
Ethylene-vinyl acetate (mass ratio 9: 1) copolymer EVAa (density 0.93 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 69 ° C., melting point 96 ° C.) synthesized by radical polymerization method Resin beads are melted at 140 ° C. and formed into a long film with a thickness of 100 μm using an extruder, and then irradiated with an electron beam at an acceleration voltage of 1 MeV and an irradiation amount of 20 Mrad using a medium energy electron beam accelerator. Thus, the supporting base material 5 forming the base film 11 was produced.

A support base 5 which forms the base film 11, the pressure-sensitive adhesive composition 1, using the adhesive composition 1 to prepare a wafer processing tape 10 in the same manner as in Example 1, which in Reference Example 5 A sample was used.

(1.6) Comparative Example 1
(Preparation of base film 11)
Zinc ionomer c (density 0.94 g / cm ³ , zinc ion content 1% by mass, chlorine) of ethylene-methacrylic acid (mass ratio 9.5: 0.5) binary copolymer synthesized by radical polymerization method Resin beads having a content of less than 1% by mass, Vicat softening point 80 ° C., melting point 98 ° C. are melted at 140 ° C. and formed into a long film having a thickness of 100 μm using an extruder. The support base 6 which makes | forms was produced.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 by using the support base material 6 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1. A sample was used.

(1.7) Comparative Example 2
(Preparation of base film 11)
Ethylene-vinyl acetate (mass ratio 9: 1) copolymer EVAa (density 0.93 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 69 ° C., melting point 96 ° C.) synthesized by radical polymerization method Resin beads were melted at 140 ° C., and formed into a long film having a thickness of 100 μm using an extruder, thereby preparing support substrate 7 forming substrate film 11.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 using the support base material 7 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1. A sample was used.

(1.8) Comparative Example 3
(Preparation of base film 11)
Melting resin beads of commercially available industrial polyvinyl chloride a (plasticizer 30% by weight, density 1.45 g / cm ³ , chlorine content 56.8% by weight, Vicat softening point 76 ° C., melting point 100 ° C.) at 140 ° C. And the support base material 8 which makes the base film 11 was produced by shape | molding into a 100-micrometer-thick elongate film shape using an extruder.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 by using the support base material 8 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1. A sample was used.

(1.9) Comparative Example 4
(Preparation of base film 11)
Resin beads of ultra-low density polyethylene ULDPEa (density 0.90 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 72 ° C., melting point 90 ° C.) synthesized by metallocene polymerization method are melted at 140 ° C. and extruded. The support base material 9 which makes the base film 11 was produced by shape | molding into a 100-micrometer-thick elongate film shape using a machine.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 using the supporting base material 9 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1, and this was used as a comparative example 4. A sample was used.

(1.10) Comparative Example 5
(Preparation of base film 11)
Low density polyethylene LDPEb (density 0.91 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 81 ° C., melting point 102 ° C.) synthesized by metallocene polymerization method is melted at 140 ° C. The support base material 10 which makes the base material film 11 was produced by shape | molding in 100-micrometer-thick elongate film shape using this.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 by using the supporting base material 10 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1. A sample was used.

(1.11) Comparative Example 6
(Preparation of base film 11)
Low density polyethylene LDPEc (density 0.91 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 96 ° C., melting point 102 ° C.) synthesized by metallocene polymerization method is melted at 140 ° C. Is formed into a long film shape having a thickness of 100 μm, and then irradiated with an electron beam at an acceleration voltage of 1 MeV and an irradiation amount of 20 Mrad using a medium energy electron beam accelerator, thereby forming a support base material 11. 11 was produced.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 using the supporting base material 11 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1. A sample was used.

(1.12) Comparative Example 7
(Preparation of base film 11)
Low density polyethylene LDPEc (density 0.91 g / cm ³ , chlorine content less than 1% by mass, Vicat softening point 96 ° C., melting point 102 ° C.) synthesized by metallocene polymerization method is melted at 140 ° C. The support base material 12 which makes the base film 11 was produced by shape | molding into a 100-micrometer-thick elongate film shape using this.

  A wafer processing tape 10 was prepared in the same manner as in Example 1 using the supporting base material 12 forming the base film 11, the pressure-sensitive adhesive composition 1, and the adhesive composition 1, and this was used as a comparative example 7. A sample was used.

(2) Sample evaluation (2.1) Increase in shrinkage stress due to heating When the wafer processing tapes of Examples 1-2 , Reference Examples 3-5, and Comparative Examples 1-7 were heated by the following method The amount of increase in shrinkage stress was measured.

After removing the adhesive layer from the wafer processing tapes of Examples 1-2 , Reference Examples 3-5, and Comparative Examples 1-7, the wafer processing tapes were processed into test pieces having dimensions defined in JIS K7162. . At this time, the longitudinal direction of the test piece (direction in which elongation strain is applied) is the winding direction when the wafer processing tape is wound into a roll shape (extrusion / winding direction (MD direction) in the extrusion molding process of the support substrate) )) And two types of test specimens were produced, one along the longitudinal direction (TD direction) perpendicular to the winding direction. Next, the test piece was subjected to 10% elongation strain by the method defined in JIS K7162 using a strograph with a heating chamber, and the distance between chucks was kept constant after applying 10% elongation strain to the test piece of the tape. The shrinkage stress was monitored in the process of heating until the temperature of the test piece reached 70 ° C, the process of maintaining the temperature at 70 ° C for 1 minute, and the process of returning the test piece to room temperature thereafter. From the obtained measurement results, the value of the initial stress immediately before the start of heating was subtracted from the observed maximum shrinkage stress value to determine the amount of increase in shrinkage stress. Tables 1 and 2 show the results when using the wafer processing tapes of each Example , each Reference Example and each Comparative Example.

(2.2) Compatibility test in semiconductor processing step The following method corresponding to the semiconductor device manufacturing method (A) described above for the wafer processing tapes of the examples , the reference examples, and the comparative examples was performed by the following method. The compatibility test in the semiconductor processing process was conducted.

(A) The process of bonding a surface protection tape to the semiconductor wafer surface in which the circuit pattern was 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 to 70 to 80 ° C., an adhesive layer of the wafer processing tape is bonded to the back surface of the semiconductor wafer, and at the same time, a wafer processing ring frame is attached to the wafer processing tape. A process in which the pressure-sensitive adhesive layer is bonded to the exposed portion without overlapping the adhesive layer.
(D) A step of peeling the surface protection tape from the surface of the semiconductor wafer.
(E) A step of irradiating a portion to be divided of the semiconductor wafer with laser light to form a modified region by multiphoton absorption inside the wafer.
(F) A step of expanding the wafer processing tape by 10% to divide the semiconductor wafer and the adhesive layer along a dividing line to obtain a plurality of semiconductor chips with the adhesive layer.
(G) A portion of the wafer processing tape that does not overlap with the semiconductor chip (an annular region between the region where the semiconductor chip is present and the ring frame) is heated to 50 ° C., 70 ° C., or 90 ° C. A heating process in which heating is continued until the tape is free of slack. Note that the heating time in this heating step was recorded. Further, after the heating step, the amount of looseness of the wafer processing tape is measured by placing a JIS B7609-compliant 10 g weight on the back surface of the base film (the surface on which the semiconductor wafer is not bonded), and the amount of looseness is less than 5 mm. It was confirmed.
(H) A step of picking up the semiconductor chip with the adhesive layer from the adhesive layer of the wafer processing tape.

(G) The amount of slack at the end of the process is measured on the back surface of the base film (the surface on which the semiconductor wafer is not bonded) with the wafer processing tape 10 being applied to the ring frame 20 as shown in FIG. A distance (a distance in FIG. 9) from a position (position indicated by a chain line in FIG. 9) in which the wafer processing tape 10 is parallel to the bonding surface of the ring frame 20 is performed by placing a JIS B7609 conforming 10 g weight. ) Was defined as the amount of slack. Tables 1 and 2 show the results of the amount of slack and the heating time when the wafer processing tapes of each example , each reference example, and each comparative example are used.

(2.3) Pickup Success Rate The yield (pickup success rate) in the final step (h) was evaluated for the wafer processing tapes of the examples , the reference examples, and the comparative examples. Tables 1 and 2 show the results when using the wafer processing tapes of each Example , each Reference Example and each Comparative Example.

(3) Summary From the above results, a thermoplastic cross-linked resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 90 ° C. and an increase in stress due to thermal shrinkage of 9 MPa or higher is used as the base film. Thus, it has been clarified that a wafer processing tape suitable for manufacturing a semiconductor device can be obtained. That is, it became clear that the heat shrinkage process at any temperature of 50 ° C., 70 ° C., and 90 ° C. showed sufficient shrinkage in a short heating time, and that there was very little looseness after the heat shrinkage process. And since the amount of looseness is small in this way, the separated semiconductor chip and the separated adhesive can be stably fixed on the wafer processing tape, and adjacent chips are damaged by contact with each other. The adhesive layers did not come into contact with each other and re-adhered, and it was revealed that good pick-up properties were exhibited. In addition, since sufficient shrinkage is exhibited in a short heating time, there is no possibility that the adhesive layer 13 and the pressure-sensitive adhesive layer 12 are brought into close contact with each other by adding an excessive amount of heat and the pickup property is not lowered.

  Those having a Vicat softening point of 90 ° C. or higher and those whose stress increase due to thermal shrinkage is less than 9.0 MPa (Comparative Examples 1, 2 and 4 to 7) require a long heating time to take looseness. Yes, the amount of looseness after the heat shrinking process is large, and the pick-up property is poor.

Note that Comparative Example 3 does not have a cross-linked structure, but the Vicat softening point is 50 ° C. or higher and lower than 90 ° C., and the increase in stress due to thermal shrinkage is 9 MPa or higher. Indicated. However, since the material is polyvinyl chloride tape, if it is incinerated after use, dioxins and chlorinated aromatic hydrocarbons, which are analogs thereof, may be generated and may cause a burden on the environment. On the other hand, since the base film 11 shown in Examples 1-2 and Reference Examples 3-5 has a crosslinked structure, the expandability is more isotropic, and the content of chlorine atoms is 1 mass. Therefore, even if it is incinerated after use, dioxins and chlorinated aromatic hydrocarbons, which are analogs thereof, are not generated and do not affect the environment.

In addition, the above-described semiconductor device manufacturing methods B to D are equivalent to the expand process, heat shrink process, and pick-up process in the semiconductor device manufacturing method A, except that the process is already divided into individual semiconductor chips in the expand process. A process is performed. Therefore, it is clear that the results when using the wafer processing tapes 10 of Examples 1-2 , Reference Examples 3-5, and Comparative Examples 1-7 are equivalent to the results shown in Tables 1 and 2. In the semiconductor device manufacturing methods B to D, the use of the wafer processing tape 10 of the present invention is useful in terms of heat shrinkability and pick-up properties. In addition, even when the wafer processing tape 10 includes only the pressure-sensitive adhesive layer 12, it is clear that the results are equivalent to the results shown in Tables 1 and 2.

DESCRIPTION OF SYMBOLS 10 Wafer processing tape 11 Base film 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 Ultraviolet light source 28 Heat shrinkage area 29 Hot air nozzle 30 Modification area 41 Push-up pin 42 Adsorption collet 50 JIS B7609 compatible 10g weight W Semiconductor wafer C Semiconductor chip a Loose amount

Claims (7)

An expandable wafer processing tape used when dividing an adhesive layer along a chip by expanding,
A base film, and an adhesive layer provided on the base film;
The base film is composed of a single layer of a thermoplastic crosslinked resin having a Vicat softening point defined by JIS K7206 of 50 ° C. or higher and lower than 90 ° C.,
The thermoplastic crosslinked resin is an ionomer resin obtained by crosslinking an ethylene- (meth) acrylic acid binary copolymer with zinc ions, or an ethylene- (meth) acrylic acid- (meth) acrylic acid alkyl ester ternary. It is an ionomer resin obtained by crosslinking a copolymer with zinc ions, and the mass ratio of the ethylene component in the copolymer is 80 to 95%, and the mass ratio of the total component of the acrylic acid component or the alkyl acrylate ester component is 5 to 20%. And the zinc ion content in the base film is 2 to 4% by mass,
After applying 10% elongation strain to the wafer processing tape test piece according to the method defined in JIS K7162, the temperature of the test piece reaches 70 ° C. while keeping the distance between chucks constant. The maximum heat shrinkage stress of the test piece in the process of heating to 70 ° C., the process of keeping the test piece at a temperature of 70 ° C. for 1 minute, and the process of returning the test piece to room temperature thereafter is higher than the initial stress immediately before the start of heating. Wafer processing tape characterized by being larger than 9 MPa.   The wafer processing tape according to claim 1, wherein an adhesive layer is laminated on the pressure-sensitive adhesive layer. 3. The wafer processing tape according to claim 1, wherein the thermoplastic crosslinked resin has a chlorine atom content of less than 1 mass%. 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 to 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) 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) 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 the adhesive layer;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
The wafer processing tape according to claim 2 , wherein the wafer processing tape is used in a method for manufacturing a semiconductor device including a wafer. 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 to 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) 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) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
The wafer processing tape according to claim 2 , wherein the wafer processing tape is used in a method for manufacturing a semiconductor device including a wafer. 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 to 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) 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) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
The wafer processing tape according to claim 2 , wherein the wafer processing tape is used in a method for manufacturing a semiconductor device including a wafer. The wafer processing tape is
(A) A semiconductor wafer on which a circuit pattern is formed using a dicing blade is cut to a depth less than the thickness of the wafer along a predetermined cutting line.
(B) bonding a surface protection tape to the surface of the semiconductor wafer;
(C) a back grinding process in which the back surface of the semiconductor wafer is ground and divided into individual semiconductor chips;
(D) A step of bonding the adhesive layer of the wafer processing tape to the back surface of the semiconductor chip in a state where the semiconductor wafer is heated to 70 to 80 ° C .;
(E) peeling the surface protection tape from the semiconductor wafer surface;
(F) dividing the adhesive layer into the semiconductor chips by expanding the wafer processing tape, and obtaining a plurality of semiconductor chips with the adhesive layers;
(G) removing the slack generated in the expanding step by heating and shrinking a portion of the wafer processing tape that does not overlap the semiconductor chip, and maintaining the interval between the semiconductor chips;
(H) picking up the semiconductor chip with the adhesive layer from an adhesive layer of a wafer processing tape;
The wafer processing tape according to claim 2 , wherein the wafer processing tape is used in a method for manufacturing a semiconductor device including a wafer.

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