Protective tape and semiconductor chip manufacturing method

Abstract

Provided is a protective tape which has a base material and an adhesive layer, is used by being adhered to an adherend and an annular frame that supports the adherend, is difficult to peel off from the annular frame, is easy to stretch after the adhesive force of the adhesive layer is reduced, has excellent conformability to recesses and protrusions, and is difficult to remain the adhesive on the adherend. The base material (2) is provided with a first resin layer (21) formed on the surface of the adhesive layer (3) side and a second resin layer (22) formed on the surface of the first resin layer (21) opposite to the adhesive layer (3), and the storage elastic modulus of the first resin layer (21) at any temperature in the range of 50 DEG C to 90 DEG C is 1.00 KPa to 200 KPa. The melting point of the second resin layer (22) measured by DSC is 80 DEG C or more and 230 DEG C or less, the thickness of the adhesive layer (3) is 20 [mu] m or less, the adhesive force of the adhesive layer (3) to stainless steel is 0.5 N / 25 mm or more, and the Young's modulus of the whole tape is 1000 MPa or less.

Description

Technical Field

[0001] This invention relates to protective tape and a method for manufacturing a semiconductor chip using the protective tape. Background Technology

[0002] In a typical semiconductor chip manufacturing process, the following steps are performed: After forming multiple semiconductor chips on a semiconductor wafer using photolithography and etching techniques, slits are formed on the semiconductor wafer along the cutting lines set between the semiconductor chips, cutting the semiconductor wafer into multiple semiconductor chips.

[0003] The cutting process is performed with the semiconductor wafer embedded in a ring frame (a frame positioned on the outside of the semiconductor wafer and supporting it), and protective tape adhered to the component forming surface of the semiconductor wafer and the ring frame. After the cutting process, and after the adhesive strength of the protective tape is reduced by ultraviolet irradiation, a process (pick-up process) is performed where the semiconductor wafer is pressed from the protective tape side to remove multiple semiconductor chips.

[0004] As a protective tape for this purpose, an adhesive film described in Patent Document 1 can be cited as an example. This adhesive film sequentially comprises a substrate layer, an intermediate layer, and an adhesive resin layer. The thickness X1 of the substrate layer is less than the thickness X2 of the intermediate layer. The storage modulus E' of the substrate layer at 85°C is 50 MPa or more and 10 GPa or less, and the storage modulus E' of the intermediate layer at 85°C is 1 MPa or more and less than 50 MPa. Specifically, the substrate layer is particularly preferably polyethylene naphthalate, and the intermediate layer is particularly preferably ethylene. Vinyl acetate copolymer.

[0005] On the other hand, Patent Document 2 describes an adhesive tape for electronic components, characterized in that it has at least one resin layer, wherein the resin layer has an energy storage elasticity of 10,000 to 200,000 Pa at any temperature between 60°C and 80°C, and a melt flow rate of 10 to 200 g / 10 min.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: WO2020 / 203287

[0009] Patent Document 2: Japanese Patent Application Publication No. 2020-174063 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] However, in the adhesive film described in Patent Document 1, the substrate (substrate layer + intermediate layer) is hard and has poor deformability, so it cannot be stretched well when pasted onto the device forming surface of the semiconductor wafer via the annular frame, thus making pasting impossible. Furthermore, even if pasted, it shrinks and peels off over time. Moreover, even if the film is stretched during the pick-up process to create distance between the semiconductor chips, it cannot be stretched well because the substrate is difficult to stretch; by applying a force to stretch the film, it peels off from the annular frame.

[0012] Furthermore, when bumps are formed on the elements of a semiconductor wafer, the surface of the semiconductor wafer on the element forming side becomes an uneven surface with a maximum height difference of 10 μm or more and 300 μm or less. However, in the adhesive film described in Patent Document 1, there is room for improvement in terms of the unevenness following when it is pasted onto such an uneven surface.

[0013] Furthermore, in terms of adhesion, a thicker adhesive layer is advantageous, as it improves the retention of the ring frame and the wafer retention during the cutting process. However, when the adhesive layer is too thick, when it is pasted on surfaces with large differences in height (the uneven surface of glass and the raised surface of semiconductor wafers), the adhesive may be lifted during the cutting process and remain on the side of the adhered object. Alternatively, monolithic adhered objects (glass lenses and semiconductor chips) may be difficult to remove during the pick-up process. Sometimes, the adhesive layer may break and remain on the adhered object during the pick-up process.

[0014] It should be noted that the tape for electronic components described in Patent Document 2 is used in the following electronic component processing method, which involves, after being pasted onto the circuit forming surface of a semiconductor wafer, cutting it according to the size of the semiconductor wafer, and then grinding the side of the semiconductor wafer opposite to the circuit forming surface.

[0015] The technical problem of the present invention is to provide a protective tape having a substrate and an adhesive layer, which is used on an object to be adhered to and a ring frame. The protective tape is difficult to peel off from the ring frame, is easy to stretch after the adhesive force of the adhesive layer is reduced, has excellent conformability to uneven surfaces, and the adhesive is difficult to leave residue on the object to be adhered to.

[0016] Technical solutions for solving technical problems

[0017] To solve the above-mentioned technical problems, one aspect of the present invention is to provide a protective tape having a substrate and an adhesive layer, which is used to adhere to an object and an annular frame supporting the object. The substrate has a first resin layer formed on the side of the adhesive layer and a second resin layer formed on the side of the first resin layer opposite to the adhesive layer. The first resin layer has a storage modulus of 1.00 kPa or more and 200 kPa or less at any temperature in the range of 50°C or more and 90°C or less. The second resin layer has a melting point of 80°C or more and 230°C or less as determined by DSC. The thickness of the adhesive layer is 20 μm or less. The adhesive layer has an adhesion force of 0.5 N / 25 mm or more to stainless steel. When in use (in the case of a diaphragm, the diaphragm is peeled off), the overall Young's modulus of the tape is 1000 MPa or less.

[0018] The effects of the invention

[0019] The protective tape of the present invention, by determining the physical properties of the first resin layer and the second resin layer constituting the substrate and the tape as a whole in use, as well as the thickness of the adhesive layer and the adhesion to stainless steel (which becomes an indicator of the adhesion to the ring frame), can be expected to be difficult to peel off from the ring frame, easy to stretch after the adhesion of the adhesive layer is reduced, and has excellent contour following properties, and the adhesive is difficult to remain on the adhered object. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view showing a protective tape corresponding to an embodiment of the present invention. Detailed Implementation

[0021] The embodiments of the present invention will be described below, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferred limitations have been made for carrying out the present invention, but these limitations are not essential to the present invention.

[0022] [Structure of protective tape]

[0023] like Figure 1 As shown, the protective tape 1 of this embodiment is composed of a substrate 2, an adhesive layer 3, and a diaphragm 4.

[0024] The substrate 2 is composed of a first resin layer 21 formed on the side of the adhesive layer 3 and a second resin layer 22 formed on the side of the first resin layer 21 opposite to the adhesive layer 3. The first resin layer 21 is in contact with the second resin layer 22.

[0025] The first resin layer 21 has a storage elastic modulus of 1.00 kPa or more and 200 kPa or less at any temperature within the range of 50°C or more and 90°C or less (e.g., 50°C, 70°C, 80°C, 90°C). The preferred range for this storage elastic modulus is 1.00 kPa or more and 200 kPa or less, a more preferred range is 10 kPa or more and 180 kPa or less, and a particularly preferred range is 40 kPa or more and 160 kPa or less.

[0026] The melting point of the second resin layer 22, determined by DSC at a heating rate of 1°C / min, is 80°C or higher and 230°C or lower. The preferred melting point range for the second resin layer 22 is 80°C or higher and 180°C or lower, and a particularly preferred range is 80°C or higher and 150°C or lower.

[0027] The resin constituting the second resin layer 22 is preferably any one of EVA (ethylene vinyl acetate copolymer), α-olefin resin, LDPE (low-density polyethylene), HDPE (high-density polyethylene), PP (polypropylene), PP / SEPS (polypropylene / styrene-hydrogenated isoprene-styrene block copolymer), polyethylene, and COC (cyclic olefin copolymer).

[0028] The Young's modulus of the protective tape 1 in the state after the diaphragm 4 has been peeled off, i.e., the Young's modulus of the tape as a whole when in use, is 1000 MPa or less. The preferred range for the overall Young's modulus of the tape is 30 MPa or more and 1000 MPa or less; a more preferred range is 30 MPa or more and 950 MPa or less; a further preferred range is 30 MPa or more and 500 MPa or less; and a particularly preferred range is 30 MPa or more and 200 MPa or less.

[0029] The thickness of the first resin layer 21 is preferably 100 μm or more and 500 μm or less, more preferably 150 μm or more and 400 μm or less, and even more preferably 200 μm or more and 350 μm or less.

[0030] The thickness of the second resin layer 22 is preferably 30 μm or more and 150 μm or less, more preferably 40 μm or more and 120 μm or less, and even more preferably 50 μm or more and 100 μm or less.

[0031] The second resin layer 22 is preferably thinner than the first resin layer 21. The ratio of the thickness of the first resin layer 21 to the thickness of the second resin layer 22, expressed as "thickness of the first resin layer 21 / thickness of the second resin layer 22", is preferably 2.0 or more and 5.0 or less, more preferably 2.5 or more and 4.0 or less, and even more preferably 2.5 or more and 3.5 or less.

[0032] The thickness of adhesive layer 3 is 20 μm or less. The thickness of adhesive layer 3 is, for example, 5 μm or more and 20 μm or less. Preferably, the thickness of adhesive layer 3 is 5 μm or more and 15 μm or less, more preferably 5 μm or more and 10 μm or less.

[0033] The adhesive layer 3, which serves as an indicator of the adhesion strength to the ring frame, has an adhesion strength to stainless steel of 0.5 N / 25 mm or more. Preferably, the adhesion strength of the adhesive layer 3 to the aforementioned stainless steel is 0.5 N / 25 mm or more and 10 N / 25 mm or less, more preferably 0.5 N / 25 mm or more and 5 N / 25 mm or less.

[0034] [Manufacturing method of protective tape]

[0035] Protective tape 1 can be manufactured, for example, by the method shown below.

[0036] First, thermoplastic resin, which forms the first resin layer 21, and thermoplastic resin, which forms the second resin layer 22, are respectively placed in an extruder and co-extruded. This yields a substrate 2, which serves as a co-extruded film.

[0037] Alternatively, a first resin layer 21 is prepared, and a thermoplastic resin, which serves as the material for forming the second resin layer 22, is extruded into a layer on one side of the first resin layer 21 and then cooled. Thus, the substrate 2 is obtained as an extruded laminate.

[0038] Next, an adhesive layer 3 is formed by coating an adhesive on one side of the diaphragm 4, thus obtaining a diaphragm with an adhesive layer.

[0039] Next, the diaphragm with the adhesive layer is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21.

[0040] [The function and effects of protective tape]

[0041] The protective tape 1 of this embodiment has a substrate 2 composed of a first resin layer 21 having a storage modulus of 1.00 kPa or more and 200 kPa or less at any temperature within the range of 50°C or more and 90°C or less, and a second resin layer 22 having a melting point of 80°C or more and 230°C or less as determined by DSC. The overall Young's modulus of the tape in use is 1000 MPa or less. Furthermore, the adhesive layer 3 has a thickness of 20 μm or less, and the adhesive force of the adhesive layer 3 on stainless steel is 0.5 N / 25 mm or more. Therefore, the protective tape 1 of this embodiment exhibits the following functions and effects.

[0042] The protective tape 1 has excellent deformability because its overall Young's modulus is below 1000 MPa, allowing for good adhesion when bonded to the component forming surface and ring frame of the semiconductor wafer. Furthermore, the protective tape 1 is easily stretched, allowing it to be stretched during the pick-up process to create distance between the semiconductor chips. It should be noted that if the Young's modulus is less than 30 MPa, the protective tape becomes too easily deformed and may be overstretched during heating; therefore, the Young's modulus is preferably 30 MPa or more and 1000 MPa or less.

[0043] Furthermore, by setting the energy storage modulus of the first resin layer 21 to 200 kPa or less, the substrate 2 exhibits excellent conformability to uneven surfaces. Therefore, even when bumps are formed on the semiconductor wafer element, and the surface of the semiconductor wafer element-forming side (the surface of the adhered object) has an uneven surface with a maximum height difference of 10 μm or more and 300 μm or less, the protective tape 1 can still be adhered perfectly. In this case, the thickness of the first resin layer 21 is preferably a value that is at least the same as this maximum value and less than 10 times that value.

[0044] Similarly, due to the excellent conformability of the substrate 2, the protective tape 1 can be properly adhered even when used on a glass surface with a maximum height difference of 10 μm or more and 300 μm or less (the surface of the object to be adhered to which multiple glass lenses are formed on a glass plate).

[0045] It should be noted that if the above-mentioned energy storage elastic modulus of the first resin layer is less than 1.00 kPa, the state of the protective tape may become unstable (for example, when the protective tape is transported in a stacked state, the first resin layer extends out, and the adjacent protective tapes in the stacking direction become joined to each other).

[0046] Furthermore, by setting the melting point of the second resin layer 22 to 80°C or higher and 230°C or lower, the Young's modulus of the tape as a whole during use can be set to 30 MPa or higher and 1000 MPa or lower.

[0047] If the melting point of the second resin layer exceeds 230°C, the Young's modulus of the tape used will greatly exceed 1000 MPa, making it difficult to deform. Therefore, when the protective tape is pasted onto the component forming surface and ring frame of the semiconductor wafer, it cannot be pasted well.

[0048] In addition, if the melting point of the second resin layer is less than 80°C, it is more likely that the melting point of the second resin layer is lower than the temperature inside the device in which it is used, and therefore it may melt and stick to the device during use.

[0049] Furthermore, the protective tape 1 makes it difficult to peel off from the ring frame by making the adhesive layer 3 adhere to the stainless steel with an adhesion force of 0.5N / 25mm or more, and makes it difficult to produce adhesive residue on the adhered object after the pick-up process by making the thickness of the adhesive layer 3 less than 20μm.

[0050] Therefore, the protective tape 1 of this embodiment is preferably used in a semiconductor chip manufacturing method, comprising: a step of pasting it onto a semiconductor wafer (the object to be pasted) and an annular frame (a frame that supports the outer edge of the object to be pasted); and a step (cutting step) after the step of forming a slit on the semiconductor wafer from the side opposite to the protective tape side to cut the semiconductor wafer into a plurality of semiconductor chips.

[0051] Furthermore, the protective tape 1 in this embodiment is a method for manufacturing the semiconductor chip described above. Preferably, the method includes: a step of reducing the adhesive force of the adhesive layer after the cutting step; and a step of pressing the semiconductor wafer from the protective tape side and removing a plurality of semiconductor chips after the cutting step (picking up step).

[0052] Furthermore, the protective tape 1 in this embodiment is a method for manufacturing the semiconductor chip described above. Preferably, the method includes a process of conveying an annular frame and a plurality of semiconductor chips in a state with the protective tape attached after a cutting process.

[0053] Furthermore, the protective tape 1 in this embodiment is a method for manufacturing the semiconductor chip described above. Preferably, it uses a method that includes: a step of reducing the adhesive strength of the adhesive layer after the above-described conveying step; and a step of pressing the semiconductor wafer from the protective tape side and removing a plurality of semiconductor chips after the step of reducing the adhesive strength.

[0054] Furthermore, the protective tape 1 of this embodiment is a manufacturing method other than semiconductor chip manufacturing, and is also preferably used in methods (a) to (d) described below.

[0055] (a): A method comprising: a step of pasting an adhesive onto an object and an annular frame supporting the object, followed by a step of forming a slit on the object from the side opposite to the protective tape side, and cutting the object into multiple individual pieces.

[0056] (b): The method according to method (a) has the following steps: after the step of cutting into individual pieces, a step of reducing the adhesive force of the adhesive layer; and after the step, a step of pressing the adhered object from the protective tape side and removing multiple individual pieces.

[0057] (c): The method according to method (a) has the following steps: after the step of cutting into individual pieces, conveying the ring frame and multiple individual pieces while they are covered with protective tape.

[0058] (d): The method according to method (c) includes: a step of reducing the adhesive force of the adhesive layer after the above-described conveying step; and a step of pressing the adhered object from the protective tape side and removing multiple individual pieces after the step of reducing the adhesive force.

[0059] Example

[0060] [Preparation of the adhesive composition that forms the adhesive layer]

[0061] A mixture of 446.5 g of 2-ethylhexyl acrylate, 45 g of methyl methacrylate, 80.0 g of methacrylic acid, and 0.5 g of benzoyl peroxide as a polymerization initiator was added dropwise over 2 hours to 400 g of toluene as a solvent, while reacting at 100 °C for 4 hours to obtain a solution of the first copolymer. 105.3 g of 2-hydroxyethyl methacrylate and 0.1 g of hydroquinone as a polymerization inhibitor were added to the obtained solution of the first copolymer, and the mixture was reacted at 120 °C for 6 hours. The reaction was then neutralized with acetic acid to obtain a solution of the second copolymer.

[0062] Polyisocyanate (CORONATE L, a trade name manufactured by Nippon Polyurethane Kogyo Co., Ltd.) and photopolymerization initiator (IRGACURE 184, a trade name manufactured by Ciba Geigy Co., Ltd.) were added to the solution of the obtained second copolymer in a mass ratio of 100:0.5 (A), 1.5 (B), and 2.0 (C):0.5, respectively, to prepare UV-curable adhesive compositions A, B, and C. That is, adhesive compositions A, B, and C are identical except for the polyisocyanate content.

[0063] [Preparation of the resin that constitutes the first resin layer]

[0064] <Determination of Energy Storage Elastic Modulus>

[0065] A 300 μm thick film composed of resins A through E was punched into a circular plate with a diameter of 8 mm to prepare test samples. Each test sample was clamped between parallel plates and operated using a viscoelasticity measuring apparatus (manufactured by Rheology Science Instruments Co., Ltd., trade name ARES) at a measurement frequency of 0.1–10 Hz and a set temperature of 23 °C. Based on the obtained data representing viscoelasticity, the dynamic shear storage modulus G' at 70 °C was determined, and this value was taken as the measured value of the storage modulus.

[0066] <Resin A>

[0067] As resin A, an ethylene-butyl acrylate copolymer (EBA) with a butyl acrylate content of 30% and a weight-average molecular weight of 100,000 was prepared. The storage modulus of resin A at 70°C, determined using the above method, was 9.0 × 10⁻⁶. 4 Pa (90 kPa), MFR 30 g / 10 min, molecular weight distribution 5.8.

[0068] <Resin B>

[0069] As resin B, an ethylene-vinyl acetate copolymer (EVA) with a vinyl acetate content of 40% and a weight-average molecular weight of 40,000 was prepared. The storage modulus of resin B at 70°C, determined using the above method, was 4.0 × 10⁻⁶. 4 Pa (40 kPa), MFR 70 g / 10 min, molecular weight distribution 6.5.

[0070] <Resin C>

[0071] As resin C, an α-olefin resin with a density of 0.89 and a weight-average molecular weight of 40,000 was prepared. The storage modulus of resin C at 70°C, determined using the above method, was 1.6 × 10⁻⁶. 5 Pa (160 kPa), MFR 40 g / 10 min, molecular weight distribution 2.4.

[0072] <Resin D>

[0073] As resin D, an ethylene-vinyl acetate copolymer (EVA) with a vinyl acetate content of 42% and a weight-average molecular weight of 40,000 was prepared. The storage modulus of resin D at 70°C, as determined by the above method, was 900 Pa (0.90 kPa), the molecular weight ratio (MFR) was 70 g / 10 min, and the molecular weight distribution was 6.5.

[0074] <Resin E>

[0075] As resin E, an α-olefin resin with a density of 0.90 and a weight-average molecular weight of 40,000 was prepared. The storage modulus of resin E at 70°C, determined using the above method, was 2.2 × 10⁻⁶. 5 Pa (220 kPa), MFR 40 g / 10 min, molecular weight distribution 2.0.

[0076] [Preparation of the resin that constitutes the second resin layer]

[0077] <HDPE>

[0078] As high-density polyethylene (HDPE), Tosoh Corporation has prepared "Nipolon Hard 2500".

[0079] <α-olefin resin>

[0080] As an α-olefin resin (polyα-olefin), "KERNEL (trademark) KS260" manufactured by Nippon Polyethylene Co., Ltd. was prepared. This resin is a metallocene olefin resin with a DSC melting point of 92°C, a Shore A hardness of 90, and a density of 0.902 g / cm³. 3 .

[0081] <PP / SEPS blended resin (elastomer)>

[0082] As homopolymer polypropylene (PP) resin, "J-105G" manufactured by Ube Industries, Ltd. was prepared, and as styrene-hydrogenated isoprene-styrene block copolymer (SEPS), "HYBRAR (registered trademark) 7125" manufactured by Kuraray Co., Ltd. was prepared. By mixing these resins at a mass ratio of 50:50, a PP / SEPS mixed resin was obtained.

[0083] <LDPE>

[0084] As low-density polyethylene (LDPE), "PETROSEN (registered trademark) 231F" manufactured by Tosoh Corporation has been prepared.

[0085] <EVA>

[0086] As an ethylene vinyl acetate copolymer (EVA), "ULTRATHENE (registered trademark) 640" manufactured by Tosoh Corporation was prepared.

[0087] <COC>

[0088] As a cyclic olefin copolymer (COC), we have prepared "TOPASS (registered trademark) 8007F-600" manufactured by Polyplastics Co., Ltd.

[0089] [Making of Protective Tape]

[0090] [Example 1]

[0091] The following was made Figure 1 1. Protective tape for the structure.

[0092] First, the HDPE and resin A are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of resin A with a thickness of 300 μm is formed on a second resin layer 22 of HDPE with a thickness of 120 μm.

[0093] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0094] Next, adhesive composition A is coated onto the 40 μm thick separator 4 made of polyethylene terephthalate (PET) with a dried film thickness of 10 μm, and the coating is dried to form adhesive layer 3. Thus, separator 4 with adhesive layer 3 is obtained.

[0095] Next, the diaphragm 4 with adhesive layer 3 is bonded with the first resin layer 21 of the substrate 2 so that the adhesive layer 3 faces the first resin layer 21, thereby transferring the adhesive layer 3 onto the first resin layer 21.

[0096] Thus, the protective tape 1 of Example 1 is obtained.

[0097] According to JIS K7127, "Test method for tensile properties of plastic films and sheets with a thickness of less than 1 mm", test pieces were prepared from the material obtained by removing the diaphragm 4 from the protective tape 1 of Example 1. The Young's modulus was determined by performing a tensile test using these test pieces. Five test pieces were used in the test, and their average value was taken as the "overall Young's modulus of the protective tape 1 of Example 1".

[0098] [Example 2]

[0099] The following was made Figure 1 1. Protective tape for the structure.

[0100] First, the α-olefin resin and the resin B are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of resin B with a thickness of 300 μm is formed on a second resin layer 22 of 100 μm made of the α-olefin resin.

[0101] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0102] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0103] Thus, the protective tape 1 of Example 2 was obtained. In addition, the Young's modulus of the protective tape 1 of Example 2 was measured using the same method as in Example 1.

[0104] [Example 3]

[0105] The following was made Figure 1 1. Protective tape for the structure.

[0106] First, using the same method as in Example 2, a substrate 2 was prepared on which a first resin layer 21 of resin B with a thickness of 300 μm was formed on a second resin layer 22 with a thickness of 100 μm made of the above-mentioned α-olefin resin, and the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22) was subjected to corona treatment.

[0107] Next, adhesive composition A is coated onto the 40 μm thick separator 4 made of polyethylene terephthalate (PET) to a thickness of 20 μm after drying, and the coating is dried to form adhesive layer 3. Thus, separator 4 with adhesive layer 3 is obtained.

[0108] The diaphragm 4 of the obtained adhesive tape layer 3 is attached with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0109] Thus, the protective tape 1 of Example 3 was obtained. In addition, the Young's modulus of the protective tape 1 of Example 3 was measured using the same method as in Example 1.

[0110] [Example 4]

[0111] The following was made Figure 1 1. Protective tape for the structure.

[0112] First, using the same method as in Example 2, a substrate 2 was prepared on which a first resin layer 21 of resin B with a thickness of 300 μm was formed on a second resin layer 22 with a thickness of 100 μm made of the above-mentioned α-olefin resin, and a corona treatment was performed on the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0113] Next, adhesive composition B is coated onto the 40 μm thick separator 4 made of polyethylene terephthalate (PET) to a thickness of 5 μm after drying, and the coating is dried to form adhesive layer 3. Thus, separator 4 with adhesive layer 3 is obtained.

[0114] The obtained diaphragm 4 with adhesive layer 3 is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0115] Thus, the protective tape 1 of Example 4 was obtained. In addition, the Young's modulus of the protective tape 1 of Example 4 was measured using the same method as in Example 1.

[0116] [Example 5]

[0117] The following was made Figure 1 1. Protective tape for the structure.

[0118] First, the PP / SEPS and the resin C are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of 300 μm thickness is formed on a second resin layer 22 of 100 μm thickness composed of the PP / SEPS.

[0119] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0120] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0121] Thus, the protective tape 1 of Example 3 was obtained. In addition, the Young's modulus of the protective tape 1 of Example 5 was measured using the same method as in Example 1.

[0122] [Example 6]

[0123] The following was made Figure 1 1. Protective tape for the structure.

[0124] First, the LDPE and the resin C are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of 300 μm thickness is formed on a second resin layer 22 of LDPE with a thickness of 300 μm.

[0125] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0126] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0127] Thus, the protective tape 1 of Example 4 was obtained. In addition, the Young's modulus of the protective tape 1 of Example 6 was measured using the same method as in Example 1.

[0128] [Comparative Example 1]

[0129] First, the HDPE and resin D are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of resin D with a thickness of 300 μm is formed on a second resin layer 22 of HDPE with a thickness of 100 μm.

[0130] Next, corona treatment is applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0131] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0132] Thus, the protective tape of Comparative Example 1 was obtained. In addition, the Young's modulus of the protective tape of Comparative Example 1 was measured using the same method as in Example 1.

[0133] [Comparative Example 2]

[0134] First, the HDPE and resin E are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of resin E with a thickness of 300 μm is formed on a second resin layer 22 of HDPE with a thickness of 100 μm.

[0135] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0136] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0137] Thus, the protective tape of Comparative Example 2 was obtained. In addition, the Young's modulus of the protective tape of Comparative Example 2 was measured using the same method as in Example 1.

[0138] [Comparative Example 3]

[0139] First, the EVA and the resin C are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of 300 μm thickness is formed on a second resin layer 22 of 100 μm thickness composed of EVA.

[0140] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0141] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0142] Thus, the protective tape of Comparative Example 3 was obtained. In addition, the Young's modulus of the protective tape of Comparative Example 3 was measured using the same method as in Example 1.

[0143] [Comparative Example 4]

[0144] First, the COC and the resin C are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 with a thickness of 300 μm is formed on a second resin layer 22 with a thickness of 100 μm made of COC.

[0145] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0146] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0147] Thus, the protective tape of Comparative Example 4 was obtained. In addition, the Young's modulus of the protective tape of Comparative Example 4 was measured using the same method as in Example 1.

[0148] [Comparative Example 5]

[0149] First, the aforementioned resin C was extruded and laminated onto a polyethylene terephthalate (PET) film with a thickness of 50 μm to a thickness of 300 μm. This produced a substrate 2 on which a first resin layer 21 of the aforementioned resin C with a thickness of 300 μm was formed on a second resin layer 22 made of PET.

[0150] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0151] Next, the diaphragm 4 with adhesive layer 3, obtained in the same manner as in Example 1, is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0152] Thus, the protective tape of Comparative Example 5 was obtained. In addition, the Young's modulus of the protective tape of Comparative Example 5 was measured using the same method as in Example 1.

[0153] [Comparative Example 6]

[0154] First, the HDPE and the resin C are placed in different extruders and co-extruded to produce a substrate 2 on which a first resin layer 21 of 300 μm thickness is formed on a second resin layer 22 of 120 μm thickness made of HDPE.

[0155] Next, a corona treatment was applied to the upper surface of the first resin layer 21 (the side opposite to the second resin layer 22).

[0156] Next, adhesive composition A is coated onto a 40 μm thick membrane made of polyethylene terephthalate (PET) to a thickness of 30 μm after drying, and the coating is dried to form adhesive layer 3. Thus, a membrane 4 with adhesive layer 3 is obtained.

[0157] Next, the obtained diaphragm 4 with adhesive layer 3 is bonded with the adhesive layer 3 facing the first resin layer 21 of the substrate 2, and the adhesive layer 3 is transferred onto the first resin layer 21 by performing the same method as in Example 1.

[0158] Thus, the protective tape of Comparative Example 6 was obtained. In addition, the Young's modulus of the protective tape of Comparative Example 6 was measured using the same method as in Example 1.

[0159] [Comparative Example 7]

[0160] An adhesive composition C is applied to a 40 μm thick polyethylene terephthalate (PET) membrane 4, with a dried film thickness of 5 μm. The coating is then dried to form an adhesive layer 3. Thus, a membrane 4 with an adhesive layer 3 is obtained.

[0161] Except for using the diaphragm 4 with adhesive layer 3 obtained in this way, the protective tape of Comparative Example 7 was obtained by the same method as Comparative Example 6. In addition, the Young's modulus of the protective tape of Comparative Example 7 was measured by the same method as in Example 1.

[0162] [Determination of adhesive strength of adhesive layer]

[0163] The adhesive strength to SUS304 of the protective tapes obtained in Examples 1-6 and Comparative Examples 1-7 was measured using a method based on JIS Z 0237. Specifically, as described below.

[0164] First, three test pieces, each 25mm wide and 300mm long, were collected from each protective tape.

[0165] Next, the 2.0 mm thick SUS304 steel plate was polished with 280 grit water-resistant abrasive paper. The adhesive layer of each test piece was placed side down on the polished surface, and a 2 kg rubber roller was pressed back and forth on each test piece 3 times, thereby pressing each test piece onto the SUS304 steel plate.

[0166] One hour after the pressing began, the adhesive strength of each test piece was measured using a tensile testing machine (STROGRAPH VE10, manufactured by Toyo Seiki Co., Ltd.) conforming to JIS B7721 standards, suitable for test values ​​within the range of 15-85% of its capacity. The measurement was conducted using the 90° peel method at a tensile speed of 50 mm / min, 23°C, and 49% relative humidity. The average value of three test points for each protective tape was taken as the adhesive strength.

[0167] [Performance Evaluation]

[0168] The performance of the protective tapes obtained in Examples 1-6 and Comparative Examples 1-7 was investigated as follows.

[0169] <Vacuum Installation Performance>

[0170] As a semiconductor wafer, a semiconductor wafer with a diameter of 200 mm (8 inches) was prepared, having bumps with a height of 200 μm and a spacing of 400 μm on the surface, and a scribing width of 100 μm, forming a semiconductor chip with a square diameter of 5 mm.

[0171] The semiconductor wafer was placed on the heated 70°C stage of a vacuum laminator (manufactured by Omiya Kogyo Co., Ltd., trade name OVM-1200MSH). Components with protective tapes attached to them on a ring frame were placed on the laminator. The ability to attach these components to the component formation surface of the semiconductor wafer under vacuum was investigated using the vacuum laminator. Components that could be attached were rated as having good vacuum mounting performance and marked "○". Components that could not be attached were rated as having poor vacuum mounting performance and marked "×".

[0172] <Following>

[0173] For wafers that can be bonded in a vacuum state through the above test, the tracking ability of the protective tape to the semiconductor wafer is visually observed after 22 hours.

[0174] A semiconductor wafer with raised bumps on its bonding surface is considered a defective product and marked with "×". A wafer with only raised bumps on the marked area is considered a permissible product and marked with "○". A wafer without raised bumps is considered a good product and marked with "◎".

[0175] <Extensibility>

[0176] The following methods were used to investigate the scalability of materials with good vacuum mounting performance.

[0177] First, a bare die with a diameter of 150 mm (6 inches) and a thickness of 350 μm was prepared, along with a ring frame of the corresponding size. Next, the bare die was attached to the ring frame using protective tape and then placed on the chip pickup device (manufactured by Canon-Machinery Co., Ltd., trade name CAP-3000II).

[0178] After setting up, with the outer periphery (outer edge) of the annular frame to which each protective tape is applied fixed, the central part (wafer part) of the worktable is lifted, thereby expanding by an extension amount of 2mm. During expansion, if the tape does not peel off, it is evaluated as good expansion and marked "○"; if the protective tape peels off from the annular frame, it is evaluated as poor expansion and marked "×".

[0179] <Ring frame retention>

[0180] First, a container was prepared to hold multiple ring frames, that is, a ring frame box with a structure that can keep each frame horizontal.

[0181] For test subjects (each test subject with different protective tapes) that were used to bond bare silicon wafers with a diameter of 200 mm (8 inches) and a thickness of 725 μm onto an 8-inch ring frame, the tape side was placed in the aforementioned ring frame box with the tape side as the lower surface and the wafer side as the upper surface. It should be noted that all bonding with different protective tapes was carried out under the same conditions (manual use of rollers).

[0182] Two hours after each test subject is placed in the ring box, the condition of the protective tape is visually confirmed. If the protective tape falls off the ring box, it is rated as poor (×). If the protective tape does not fall off the ring box but a part of the protective tape peels off, it is rated as acceptable (○). If the protective tape does not peel off at all, it is rated as excellent (◎).

[0183] <State of the peeled-off surface (the side from which the protective tape has been removed)>

[0184] The following test was conducted to investigate the condition of the peeled surface (the surface from which the protective tape was peeled off) only for cases where the followability and ring frame retention were good (○ or ◎).

[0185] First, for each protective tape after visual observation in the above follow-up evaluation, the cumulative irradiation dose was 200 mJ / mm² from the substrate side.2 Irradiation with ultraviolet light (wavelength 365nm) reduces the adhesive strength of the adhesive layer.

[0186] Next, using a tensile testing machine (STROGRAPH VE10 (trade name) manufactured by Toyo Seiki Co., Ltd.), according to JIS Z 0237 (2009), "10.4 Determination of Peel Adhesion," specifically "10.4.1 Method 1: 180-degree peel adhesion for test plates," the protective tape on the annular frame was grasped and peeled off. The tensile speed was 300 mm / min.

[0187] Then, the surface of the semiconductor wafer after the protective tape was removed (the peeled surface) was observed using an optical microscope to investigate whether any adhesive residue remained on the semiconductor wafer surface. The adhesive residue was in the form of clumps or whiskers. The case where adhesive residue remained on the bump portion of the semiconductor wafer surface was evaluated as undesirable (×), the case where adhesive residue remained on a portion other than the bump portion (scribing lines, etc.) was evaluated as practically acceptable (○), and the case where there was no adhesive residue left on the semiconductor wafer surface was evaluated as exceptionally good (◎).

[0188] <Stability>

[0189] When conveyed in a stacked state, if adjacent protective tapes in the stacking direction stick to each other, or if the temperature inside the device being used is high and the protective tapes melt and may stick inside the device, the evaluation is "×"; if there is no such possibility, the evaluation is "○".

[0190] <Overall Evaluation>

[0191] When all performance indicators are marked "○" or "◎", the overall evaluation is good and is recorded as "○". When any performance indicator is marked "×", the overall evaluation is poor and is recorded as "×".

[0192] These results, along with the structure of each protective tape, are presented in Table 1 below. It should be noted that "-" in Table 1 indicates that no corresponding performance tests were conducted.

[0193] It should be noted that Comparative Example 1 and Comparative Example 3 were rated as unsatisfactory in terms of stability, for the reasons described below.

[0194] In Comparative Example 1, the protective tape has a first resin layer with a storage modulus of less than 1.00 kPa at 70°C. Therefore, when transported in a laminated state, the first resin layer may extend, causing adjacent protective tapes in the lamination direction to bond together. In Comparative Example 3, the protective tape has a second resin layer with a melting point of 75°C. Therefore, if the temperature inside the device is 75°C or higher, it may melt and adhere to the device during use.

[0195] [Table 1]

[0196] As shown in Table 1, the protective tapes of Examples 1-6 have the following properties: the first resin layer 21 has a storage modulus of 40 kPa or more and 160 kPa or less at 70°C; the second resin layer 22 has a melting point of 83°C or more and 128°C or less as determined by DSC; the overall Young's modulus of the tapes in use is 35 MPa or more and 950 MPa or less; the thickness of the first resin layer 21 is 1.5 times (300 μm) the maximum value of the unevenness of the semiconductor wafer surface (200 μm); the adhesive layer 3 has a thickness of 5 μm or more and 20 μm or less; the adhesive force of the adhesive layer 3 on stainless steel is 0.6 N / 25 mm or more; and the vacuum mounting performance, tracking, expansion, ring frame retention, peeled surface condition, and stability are all excellent.

[0197] In contrast, the protective tape of Comparative Example 1 is excellent in terms of vacuum installation performance, followability, spreadability, ring frame retention and the condition of the peeled surface, but as mentioned above, the first resin layer has poor stability because its energy storage modulus at 70°C is less than 1.00 kPa.

[0198] The protective tape of Comparative Example 2 is excellent in terms of vacuum installation performance, expandability, ring frame retention and stability, but its followability is poor because the energy storage modulus of the first resin layer at 70°C exceeds 200 kPa.

[0199] The protective tape of Comparative Example 3 has excellent ring frame retention, but its stability is poor as described above because the melting point of the second resin layer, as determined by DSC, is less than 80°C. Furthermore, because the overall Young's modulus of the tape during use is less than 30 MPa, it is overstretched when bonded using a vacuum laminator and cannot be bonded.

[0200] The protective tape of Comparative Example 4 is excellent in terms of vacuum installation performance, followability, ring frame retention, peel surface condition, and stability, but the overall Young's modulus of the tape exceeds 1000 MPa during use, resulting in poor extensibility.

[0201] The protective tape of Comparative Example 5 has a Young's modulus of 3650 MPa, which is significantly higher than 1000 MPa, because the melting point of the second resin layer, as determined by DSC, exceeds 230°C. Therefore, it cannot be deformed or bonded when using a vacuum laminator.

[0202] The protective tape of Comparative Example 6 is excellent in terms of vacuum installation performance, followability, spreadability, ring frame retention and stability, but the thickness of the adhesive layer 3 is too thick, at 30 μm, so there is adhesive residue on the bonded surface and the condition of the peeled surface is poor.

[0203] The protective tape of Comparative Example 7 has excellent vacuum installation performance, followability, spreadability and stability, but the adhesion of adhesive layer 3 to stainless steel is insufficient, at 0.4N / 25mm, resulting in poor retention of the ring frame.

[0204] Explanation of reference numerals in the attached figures

[0205] 1: Protective tape; 2: Substrate; 3: Adhesive layer; 4: Separator; 21: First resin layer; 22: Second resin layer.

Claims

1. A protective tape having a base material and an adhesive layer, which is used by being attached to an adherend and a ring-shaped frame that supports the adherend, the base material is provided with a first resin layer formed on a surface of the adhesive layer side, and a second resin layer formed on a surface of the first resin layer opposite to the adhesive layer, the first resin layer has a storage elastic modulus of 1.00 KPa or more and 200 KPa or less at any one temperature in a range of 50°C or more and 90°C or less, the second resin layer has a melting point of 80°C or more and 230°C or less as measured by a DSC method, the thickness of the adhesive layer is 20 μm or less, the adhesive force of the adhesive layer to stainless steel is 0.5 N / 25 mm or more, the Young's modulus of the entire tape in use is 1000 MPa or less.

2. The protective tape according to claim 1, wherein the Young's modulus of the entire tape in use is 30 MPa or more and 1000 MPa or less.

3. The protective tape according to claim 1, wherein the first resin layer is in contact with the second resin layer.

4. The protective tape according to claim 1, wherein the protective tape is used by being attached to a surface of the adherend having a concavo-convex, the maximum value of the height difference of the concavo-convex being 10 μm or more and 300 μm or less.

5. The protective tape according to claim 4, wherein the thickness of the first resin layer is a dimension in a range of a value of the same as the maximum value of the height difference of the concavo-convex or more and a value of 10 times or less.

6. The protective tape according to claim 1, wherein the resin constituting the second resin layer is any one of an ethylene-vinyl acetate copolymer EVA, an alpha olefin resin, a low-density polyethylene LDPE, a high-density polyethylene HDPE, a polypropylene PP, a polypropylene / styrene- hydrogenated isoprene-styrene block copolymer PP / SEPS, and a cyclic olefin copolymer COC.

7. The protective tape according to claim 4, wherein the adherend is glass.

8. The protective tape according to claim 4, wherein the adherend is a semiconductor wafer.

9. A manufacturing method of a semiconductor chip, comprising: a step of attaching the protective tape according to claim 1 to a semiconductor wafer as the adherend and the ring-shaped frame; and a step of forming a scribe on the semiconductor wafer from a side opposite to the protective tape side after the attaching step, and cutting the semiconductor wafer into a plurality of semiconductor chips.

10. The manufacturing method of a semiconductor chip according to claim 9, wherein the manufacturing method comprises: a step of reducing the adhesive force of the adhesive layer after the cutting step; and a step of pressing the semiconductor wafer from the protective tape side and taking out the plurality of semiconductor chips after the step of reducing the adhesive force.

11. The manufacturing method of a semiconductor chip according to claim 9, wherein the manufacturing method comprises a step of transporting the ring-shaped frame and the plurality of semiconductor chips in a state where the protective tape is attached after the cutting step.

12. The method of manufacturing a semiconductor chip according to claim 11, wherein the manufacturing method has: a process of reducing the adhesion of the adhesive layer after the process of transporting; and a process of taking out the plurality of semiconductor chips by pressing the semiconductor wafer from the protective tape side after the process of reducing the adhesion.

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