Protective film for wafer

Abstract

Disclosed is a protective film for wafers, which has excellent 5% tensile modulus at room temperature and excellent adhesion at room temperature after lamination in which the protective film is attached to one surface of a semiconductor wafer at a temperature of 80 DEG C, thereby enabling reuse of the semiconductor wafer. The protective film for a wafer according to the present invention comprises: a substrate layer; the bonding layer is arranged on the base material layer; and the protective layer is arranged on the bonding layer. After the protective layer is attached to one side of the wafer at the temperature of 80 DEG C, when the protective layer is peeled off at normal temperature, the normal-temperature adhesive force of the protective layer to the wafer is 30-100 gf / 25 mm, and the 5% tensile modulus of the protective layer measured at normal temperature is 1.0-3.0 MPa.

Description

Technical Field

[0001] The present invention relates to a protective film sheet for wafers, which has excellent 5% tensile modulus at room temperature and excellent room temperature adhesion after lamination of attaching the protective film sheet to one side of a semiconductor wafer at a temperature of 80°C, thereby enabling the reuse (reprocessing) of the semiconductor wafer. Background Art

[0002] The semiconductor process is divided into a front process of preparing a wafer and engraving a circuit and a rear process of packaging a chip.

[0003] In the rear process, in the packaging process, in order to protect the semiconductor from impact or moisture, a technique of using a material such as plastic to wrap a protective film and connecting an external terminal to a chip is adopted. The packaging process is carried out in multiple steps, including a back grinding step of grinding the back of the wafer to make it thinner in a manner that conforms to product characteristics, a cutting step of cutting the wafer, and an adhesion step of enabling the chip to transmit and receive external electrical signals.

[0004] Before the cutting process, in the wafer pasting process, lamination of attaching a protective film sheet to the wafer that has been subjected to back grinding treatment is carried out. In this case, if impurities or air bubbles flow between the wafer and the protective film sheet, or the protective film sheet attached to the wafer wrinkles, the protective film sheet needs to be peeled off from the wafer and then the process of attaching the protective film sheet to the wafer again is usually carried out.

[0005] However, in the process of peeling the protective film sheet from the wafer, the adhesive component of the protective film sheet remains on the wafer surface, or the wafer is damaged due to the excessive adhesive force of the protective film sheet. Therefore, there is a problem that the expensive wafer cannot be reused and is discarded as a defective product.

[0006] Therefore, it is necessary to study a protective film sheet that enables the reuse of the wafer. Summary of the Invention

[0007] Technical Problem

[0008] An object of the present invention is to provide a protective film sheet that simultaneously satisfies the conditions of having a 5% tensile modulus of 1.0 to 3.0 MPa at room temperature and a room temperature adhesion of 30 to 100 gf / 25 mm after lamination at a temperature of 80°C, so that when peeling the protective film sheet attached to one side of the wafer, no residue remains on the wafer surface, thereby enabling the reuse of the wafer.

[0009] Moreover, an object of the present invention is to provide a protective film sheet with excellent laser marking properties.

[0010] Furthermore, an object of the present invention is to provide a wafer-protective layer assembly including a protective layer with excellent reprocessing characteristics.

[0011] The object of the present invention is not limited to the above-mentioned objects, and other objects and advantages of the present invention not mentioned can be understood from the following description and can be more clearly understood through the embodiments of the present invention. And it goes without saying that the objects and advantages of the present invention can be achieved by the methods and their combinations shown in the claims of the invention.

[0012] Technical solution

[0013] The protective film sheet of the present invention is characterized in that it includes: a substrate layer; an adhesive layer provided on the substrate layer; and a protective layer provided on the adhesive layer. After attaching the protective layer to one side of the wafer at a temperature of 80°C, when the protective layer is peeled off at room temperature, the room-temperature adhesion force of the protective layer to the wafer is 30 to 100 gf / 25 mm, and the 5% tensile modulus of the protective layer measured at room temperature is 1.0 to 3.0 MPa.

[0014] The room-temperature elongation rate of the protective layer can be 100% or more.

[0015] The protective layer may include an acrylic binder, an epoxy resin, an amine curing agent, an imidazole accelerator, a filler, a colorant, and an additive.

[0016] The weight-average molecular weight (Mw) of the acrylic binder constituting the protective layer can be 4×10 5 ~12×10 5 g / mol, and the glass transition temperature (Tg) can be 1 to 20°C.

[0017] The epoxy resin constituting the protective layer includes a phenolic epoxy resin and a bisphenol epoxy resin, and the content of the phenolic epoxy resin can be less than the content of the bisphenol epoxy resin.

[0018] The equivalent weight of the amine curing agent constituting the protective layer can be 65 g / eq or less.

[0019] Relative to the total 100 weight percentages of the protective layer, it may include 15 to 20 weight percentages of an acrylic binder and 5 to 30 weight percentages of an epoxy resin.

[0020] The substrate layer may include a polyolefin resin. The adhesive layer may include one or more pressure-sensitive adhesives (PSA) such as rubber, acrylic resin, and silicone resin, a curing agent, and an initiator.

[0021] The wafer-protective layer assembly of the present invention is characterized in that it includes: a wafer formed with semiconductor chips; and the protective layer described above, provided on one side of the wafer. After attaching the protective layer to one side of the wafer at a temperature of 80°C, when the protective layer is peeled off at room temperature, the room-temperature adhesion of the protective layer to the wafer is 30 to 100 gf / 25 mm, and the 5% tensile modulus of the protective layer measured at room temperature is 1.0 to 3.0 MPa.

[0022] Effects of the Invention

[0023] The protective film sheet for wafers of the present invention simultaneously satisfies the conditions that the 5% tensile modulus measured at room temperature is 1.0 to 3.0 MPa and the room-temperature adhesion after lamination at a temperature of 80°C is 30 to 100 gf / 25 mm, has excellent adhesiveness and peelability, and has the effect of enabling the reuse (reprocessing) of wafers. Since the expensive wafers are reused together with the protective film sheet, there is an effect of saving manufacturing costs.

[0024] Moreover, the protective film sheet for wafers of the present invention has the excellent effect of laser marking.

[0025] The specific effects of the present invention will be described together with the above effects in the process of describing the specific embodiments below. Description of the Drawings

[0026] Figure 1 It is a cross-sectional view of the protective film sheet for wafers of the present invention.

[0027] Figure 2 It is a top view ((a) part) and a side view ((b) part) showing the laminated state in which a protective film sheet is attached to one side of the wafer of the present invention.

[0028] Description of the Reference Numerals:

[0029] 10: Protective layer;

[0030] 20: Adhesive layer;

[0031] 30: Substrate layer;

[0032] 50: Ring-shaped frame;

[0033] W: Wafer. Detailed Description of the Invention

[0034] In the following content, the foregoing objects, features, and advantages will be described in detail with reference to the accompanying drawings, and those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention based thereon. In the process of describing the present invention, when it is determined that a detailed description of the well-known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings are used to indicate the same or similar structural elements.

[0035] In the following content, the description that any structure is provided "above (or below)" a structural element or "on (or under)" a structural element not only means that any structure is provided in contact with the upper (or lower) surface of the structural element, but also means that other structures may be interposed between the structural element and any structural element provided on (or under) the structural element.

[0036] Moreover, in the case where a certain structural element is described as "connected", "joined", or "coupled" to another structural element, it should be understood not only that the structural elements are directly connected or coupled to each other, but also that other structural elements may be "interposed" between the structural elements, or that the structural elements are "connected", "joined", or "coupled" through other structural elements.

[0037] Hereinafter, a protective film sheet for a wafer according to several embodiments of the present invention will be described.

[0038] In the encapsulation process, lamination is performed to attach a protective film sheet to one side of the wafer. In this case, if impurities or air bubbles flow between the wafer and the protective film sheet, or if the protective film sheet is not well attached to the wafer, after peeling off the protective film sheet from the wafer, an attempt is made to reattach the protective film sheet.

[0039] However, if the adhesive force of the protective film sheet is too high, the protective film sheet tears or the wafer is damaged, resulting in the problem that the wafer is difficult to reuse. On the contrary, if the adhesive force of the protective film sheet is too low, the removal sheet is peeled off together with the protective film sheet, resulting in the problem that lamination cannot be fully achieved.

[0040] Therefore, the expensive wafer is often discarded because it cannot be reused.

[0041] To solve the above problems, the present inventors have studied a protective film sheet that can reuse the wafer.

[0042] The present inventors have confirmed that in the protective layer, adhesive layer, and base material layer constituting the protective film sheet, when the protective layer in direct contact with the wafer simultaneously satisfies the normal temperature adhesive force and normal temperature tensile modulus after lamination at 80 °C, no residue remains on the wafer surface when peeling off the protective film sheet from the wafer, thereby making it possible to reuse the wafer.

[0043] In addition, it is confirmed that excellent laser marking properties are achieved by adding a colorant into the protective layer.

[0044] Therefore, in the present invention, a protective film sheet with excellent reprocessability (reworkability) is provided by including a protective layer that satisfies a 5% tensile modulus of 1.0 to 3.0 MPa at room temperature and a room-temperature adhesion of 30 to 100 gf / 25 mm after lamination at 80°C.

[0045] As Figure 1 and Figure 2 shown in part (a) of [], the protective film sheet of the present invention includes a protective layer 10 that directly contacts the wafer W, and has a structure in which an adhesive layer 20 and a substrate layer 30 are sequentially laminated below the protective layer 10.

[0046] That is, it includes a protective layer 10 provided below the wafer, an adhesive layer 20 provided below the protective layer 10, and a substrate layer 30 provided below the adhesive layer 20.

[0047] As Figure 2 shown in part (b) of [], lamination can be performed in a state where an annular frame 50 for supporting the wafer is provided in the outer peripheral region of the wafer, so that the protective layer directly contacts the back surface of the wafer.

[0048] The protective layer 10 also remains attached to the back surface of the wafer during subsequent processes such as a dicing step and a single-chip picking step.

[0049] The adhesive layer 20 and the substrate layer 30 are removed as process tapes.

[0050] The protective film sheet of the present invention is not a polishing process sheet (tape), but a sheet used for lamination of attaching a protective film sheet to the back surface of a wafer during a wafer bonding process before a dicing process.

[0051] The protective layer 10 in the protective film sheet has no adhesiveness at room temperature (25 ± 2°C) before curing at a temperature of 60 to 80°C or before lamination at a temperature of 60 to 80°C.

[0052] However, after laminating the wafer and the protective layer at a temperature of 60 to 80°C, when peeling the protective layer at room temperature, preferably, the room-temperature adhesiveness of the protective layer satisfies 30 to 100 gf / 25 mm. And more preferably, the room-temperature adhesiveness of the protective layer satisfies 35 to 90 gf / 25 mm, and even more preferably, it satisfies 35 to 80 gf / 25 mm.

[0053] The room-temperature adhesiveness of the protective layer laminated at 80°C satisfies 30 to 100 gf / 25 mm, so that the protective layer can be easily peeled off from the wafer, and no residue such as an adhesive component remains on the wafer surface at all, having the effect of easily performing reprocessing.

[0054] If the normal temperature adhesion after lamination at 80 °C is less than 30 gf / 25 mm, the lamination of the wafer and the protective film cannot be properly formed because the adhesive layer and the substrate layer are detached from the protective layer.

[0055] On the contrary, if the normal temperature adhesion after lamination at 80 °C is greater than 100 gf / 25 mm, there will be a problem that it is difficult to reprocess because the protective layer is torn or the wafer is damaged when the protective layer is peeled off from the wafer.

[0056] And preferably, the 5% tensile modulus of the protective layer at normal temperature satisfies 1.0 to 3.0 MPa, and more preferably, it satisfies 1.1 to 2.8 MPa.

[0057] 5% tensile means that the length is stretched by 5% relative to the length before elongation, that is, the elongation rate is 5%.

[0058] The tensile modulus refers to the modulus value when the material is stretched or dragged.

[0059] As an inherent physical property value of the protective layer, the 5% tensile modulus at normal temperature can show 1.0 to 3.0 MPa.

[0060] The 5% tensile modulus of the protective layer at normal temperature satisfies 1.0 to 3.0 MPa, maintaining the mechanical strength of the protective layer to prevent the layer from being torn, thus having the effect of facilitating reprocessing.

[0061] If the 5% tensile modulus at normal temperature is less than 1.0 MPa or greater than 3.0 MPa, it will be difficult to reprocess due to the reduction of the physical properties of the protective layer.

[0062] And preferably, the elongation rate of the protective layer at normal temperature is 100% or more, more preferably, it is 130 to 350%, and even more preferably, it is 150 to 320%.

[0063] The elongation rate is the ratio of elongation in the elongation test, also known as the elongation at break.

[0064] The elongation rate of the protective layer at normal temperature satisfies 100% or more, so that when the protective layer is peeled off from the wafer, it has an excellent peeling property for the wafer without residual adhesive components on the wafer.

[0065] The protective layer 10 may include an acrylic binder, an epoxy resin, an amine curing agent, an imidazole accelerator, a filler, a colorant, and an additive.

[0066] The weight average molecular weight, glass transition temperature and content of the binder, the content of the epoxy resin, and the equivalent of the curing agent, etc. can be adjusted to meet the normal temperature adhesion, 5% tensile modulus at normal temperature, and elongation rate at normal temperature of the protective layer.

[0067] In the protective layer, the physical properties of the protective layer can be controlled according to the weight average molecular weight and content of the acrylic binder and epoxy resin.

[0068] Specifically, the weight average molecular weight (Mw) of the acrylic binder constituting the protective layer can be 4×10 5 ~12×10 5 g / mol, preferably, it can be 6×10 5 ~12×10 5 g / mol, more preferably, it can be 8×10 5 ~12×10 5 g / mol.

[0069] When the weight average molecular weight (Mw) of the acrylic binder satisfies 4×10 5 ~12×10 5 g / mol, it has the effect of being beneficial to exhibiting the physical properties of the protective layer required for reprocessability.

[0070] If the weight average molecular weight of the acrylic binder is less than 4×10 5 g / mol, there is a problem that reprocessing is difficult due to a decrease in the 5% tensile modulus at room temperature.

[0071] On the contrary, if the weight average molecular weight of the acrylic binder is greater than 12×10 5 g / mol, the compatibility with the epoxy resin is insufficient due to the excessive weight average molecular weight of the acrylic binder, resulting in a problem of reduced adhesion to the adhesive interface.

[0072] The glass transition temperature (Tg) of the acrylic binder can be 1 to 20 °C, preferably, it can be 1 to 15 °C, more preferably, it can be 4 to 15 °C.

[0073] When the Tg of the acrylic binder satisfies 1 to 20 °C, it has the effect of being beneficial to exhibiting the physical properties of the protective layer required for reprocessability.

[0074] If the Tg of the acrylic binder is less than 1 °C, the 5% tensile modulus measured at room temperature is low, resulting in a problem of excessive room temperature adhesion of the protective layer.

[0075] On the contrary, if the Tg of the acrylic binder is greater than 20 °C, there is a problem of insufficient adhesion due to the hardening of the protective layer.

[0076] Relative to the total 100 weight percentages of the protective layer, 15 to 20 weight percentages of the acrylic binder can be included.

[0077] If the content of the acrylic binder is less than 15% by weight, it will be difficult to reprocess due to the increase in the room temperature adhesive force after lamination of the protective layer at a temperature of 80°C.

[0078] On the contrary, if the content of the acrylic binder is greater than 20% by weight, there are problems of reduced adhesive force of the protective layer and insufficient heat resistance.

[0079] For example, the acrylic binder may include one or more of an acrylic copolymer resin, a urethane acrylate resin, and a glycidyl acrylate resin. The acrylic copolymer resin may be a copolymer of ethyl acrylate, butyl acrylate, methyl methacrylate, glycidyl acrylate, and acrylonitrile.

[0080] The epoxy resin constituting the protective layer may include a phenolic epoxy resin and a bisphenol epoxy resin.

[0081] The phenolic epoxy resin and the bisphenol epoxy resin may be included simultaneously as the epoxy resin, thereby having the advantageous effect of simultaneously exhibiting the adhesiveness and reprocessability of the protective layer.

[0082] In this case, preferably, the content of the phenolic epoxy resin is less than the content of the bisphenol epoxy resin.

[0083] If the content of the phenolic epoxy resin is more than the content of the bisphenol epoxy resin, there is a problem that the 5% tensile modulus increases at room temperature, resulting in tearing of the adhesive layer and reduced reprocessability.

[0084] Relative to the total 100% by weight of the protective layer, 5 to 30% by weight of the epoxy resin may be included. Preferably, 10 to 25% by weight may be included, and more preferably, 15 to 24% by weight may be included.

[0085] The content of the epoxy resin satisfies 5 to 30% by weight, so as to have the advantage of showing a room temperature adhesive force of 30 to 100 gf / 25 mm after lamination at a temperature of 80°C.

[0086] For example, the phenolic epoxy resin may include one or more of a phenol novolac epoxy resin, a cresol novolac epoxy resin, and a bisphenol A modified phenol novolac epoxy resin. The bisphenol epoxy resin may include one or more of a bisphenol F diglycidyl ether type epoxy resin, a bisphenol A diglycidyl ether type epoxy resin, a bisphenol A diglycidyl ether type epoxy resin added with polyolefin, and a bisphenol F diglycidyl ether type epoxy resin added with polyolefin.

[0087] For the curing reaction of the acrylic binder and the epoxy resin, the protective layer may include a curing agent.

[0088] However, if a resin-based curing agent with a high equivalent weight of 100 g / eq or more is used for the protective layer, there is a problem that the reprocessability of the protective layer is significantly reduced.

[0089] To solve such a problem, the present invention ensures excellent reprocessability of the protective layer by using a powder-type curing agent with a low equivalent weight.

[0090] As the powder-type curing agent with a low equivalent weight, the equivalent weight of the amine-based curing agent can be 65 g / eq or less, preferably 5 - 62 g / eq, more preferably 20 - 62 g / eq, and even more preferably 40 - 62 g / eq.

[0091] The lower the equivalent weight of the amine-based curing agent, the more advantageous it is for the 5% tensile modulus of the protective layer at room temperature to show 1.0 - 3.0 MPa.

[0092] For example, the amine-based curing agent can include one or more of modified alicyclic amine curing agents, aliphatic amine curing agents, amidoamine curing agents, and phenalkamine curing agents.

[0093] The modified type of curing agent refers to a curing agent that improves effects such as adhesion by modifying aliphatic amines such as ethylenediamine (EDA, Ethylene Diamine), diethylenetriamine (DETA, Diethylene Triamine), triethylenetetramine (TETA, Triethylene Tetramine), tetraethylenepentamine (TEPA, Tetraethylene Pentamine), and alicyclic amines such as methylene dianiline (MDA, Methylene Dianiline), isophorone diamine (IPDA, Isophorone Diamine), etc.

[0094] The curing reaction of aliphatic amine curing agents with epoxy resins is rapid and the adhesion is excellent. For example, there are ethylenediamine, diethylenetriamine, etc.

[0095] Amidoamine curing agents have chemical resistance and strong adhesion. For example, there are polyamidoamine, polyketone amidoamine, etc. Phenalkamine curing agents have excellent compatibility with epoxy resins and a fast curing rate.

[0096] Relative to the total 100 weight percentages of the protective layer, 1 - 10 weight percentages of the amine-based curing agent can be included, preferably 3 - 8 weight percentages. The content of the amine-based curing agent satisfies 1 - 10 weight percentages, so as to have the advantage that the room-temperature adhesion force shows 30 - 100 gf / 25 mm after lamination at a temperature of 80°C.

[0097] The imidazole accelerator that forms the protective layer promotes the curing reaction of the protective layer.

[0098] Relative to the total 100 weight percentages of the protective layer, 0.1 to 2 weight percentages of the imidazole accelerator may be included. Preferably, 0.1 to 1 weight percentage may be included.

[0099] The content of the imidazole accelerator satisfies 0.1 to 2 weight percentages, having the following advantages: not delaying the curing reaction time, being beneficial for the room-temperature bonding strength to show 30 to 100 gf / 25 mm after lamination at a temperature of 80°C.

[0100] For example, imidazole accelerators can include 2-methylimidazole (2MZ), 2-undecylimidazole (C11-Z), 2-heptadecylimidazole (C17Z), 1,2-dimethylimidazole (1.2DMZ), 2-ethyl-4-methylimidazole (2E4MZ), 2-phenylimidazole (2PZ), 2-phenyl-4-methylimidazole (2P4MZ), 1-benzyl-2-methylimidazole (1B2MZ), 1-benzyl-2-phenylimidazole (1B2PZ), 1-cyanoethyl-2-methylimidazole (2MZ-CN), 1-cyanoethyl-2-ethyl-4-methylimidazole (2E4MZ-CN), 1-cyanoethyl-2-undecylimidazole (C11Z-CN), 1-cyanoethyl-2-phenylimidazolium trimellitate (2PZCNS-PW), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (2MZ-A), 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine (C11Z-A), 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine (2E4MZ-A), 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (2,One or more of 4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (2MA-OK), 2-phenyl-4,5-dihydroxymethylimidazole (2PHZ-PW), and 2-phenyl-4-methyl-5-hydroxymethylimidazole (2P4MHZ-PW).

[0101] The filler that constitutes the protective layer acts as a filling material and improves the hardness of the protective layer.

[0102] The filler may include an organic filler and / or an inorganic filler.

[0103] For example, the inorganic filler may include one or more of spherical silica, alumina, talc, calcium carbonate, silicon carbide, boron nitride, and glass fiber.

[0104] Relative to the total 100 weight percentages of the protective layer, 40 to 70 weight percentages of the filler may be included, and preferably, 50 to 60 weight percentages may be included. The content of the filler satisfies 40 to 70 weight percentages, so that sufficient hardness and reliability for protecting the wafer can be shown.

[0105] The colorant that constitutes the protective layer can improve the recognition of laser marking.

[0106] The colorant may include an organic pigment and / or an inorganic pigment. For example, the organic pigment may be an ammonium pigment, a cyanine pigment, a merocyanine pigment, a croconic acid pigment, a squarylium pigment, a azulium pigment, a polymethine pigment, a naphthoquinone pigment, a pyranylium pigment, a phthalocyanine pigment, a naphthalocyanine pigment, a naphtholactam pigment, an azo pigment, a condensed azo pigment, an indigo pigment, a perinone pigment, a perylene pigment, a dioxazine pigment, a quinacridone pigment, an isoindolinone pigment, a quinonaphthone pigment, a pyrrole pigment, a thioindigo pigment, a metal complex pigment (metal complex dye), a dithiol metal complex pigment, an indophenol pigment, a triallylmethane pigment, an anthraquinone pigment, a dioxazine pigment, a naphthol pigment, a azomethine pigment, a benzimidazolone dye, a peryleneanthrone dye, a vat pigment, etc. The inorganic pigment may include carbon black, cobalt pigment, iron pigment, chromium pigment, titanium pigment, vanadium pigment, zirconium pigment, molybdenum pigment, ruthenium pigment, platinum pigment, indium tin oxide (ITO) pigment, antimony-doped tin oxide (ATO) pigment, etc.

[0107] The protective layer, relative to 100% by weight in total, may contain 0.1 to 2% by weight of a colorant, preferably, it may contain 0.1 to 1% by weight.

[0108] When the content of the colorant satisfies 0.1 to 2% by weight, the cutting step and the individual chip separation step can proceed smoothly in subsequent processes due to excellent laser marking properties.

[0109] Moreover, when the protective layer contains the colorant together with the binder, epoxy resin, and filler, it can have excellent laser marking properties while having the mechanical strength capable of protecting the back of the semiconductor chip.

[0110] The additive has the following advantages: it is beneficial for the protective layer to show a normal temperature adhesive force of 30 to 100 gf / 25 mm after lamination at a temperature of 80°C and a normal temperature 5% tensile modulus of 1.0 to 3.0 MPa.

[0111] The additive may contain a silane coupling agent. For example, the silane coupling agent may contain 3-glycidoxypropyltrimethoxysilane, 3-glycidoxymethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-(phenylamino)propyltrimethoxysilane, (3-ureidopropyl)triethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazole silane, etc.

[0112] The protective layer, relative to 100% by weight in total, may contain 0.5 to 2% by weight of the additive, preferably, it may contain 0.5 to 1% by weight. When the content of the additive satisfies 0.5 to 2% by weight, it has the advantage of being beneficial for exhibiting the physical properties of the protective layer required for reprocessability.

[0113] Thus, the protective layer of the present invention can be prepared from a protective layer composition containing 15 to 20% by weight of an acrylic binder, 5 to 30% by weight of an epoxy resin, 1 to 10% by weight of an amine curing agent, 0.1 to 2% by weight of an imidazole accelerator, 40 to 70% by weight of a filler, 0.1 to 2% by weight of a colorant, and 0.5 to 2% by weight of an additive.

[0114] When preparing the protective layer composition, an organic solvent for adjusting viscosity can be used, but it is not limited thereto.

[0115] The protective layer which is a cured product of the composition used as the protective layer is in a state without adhesiveness at normal temperature, and can be laminated with the wafer at a high temperature, that is, after lamination at a temperature of 80°C, the adhesiveness at normal temperature can show 30 gf / 25 mm or more.

[0116] The base material layer and the adhesive layer in the protective film sheet can be removed as a process tape without being reused.

[0117] In the dicing step or the individual chip separation step, when ultraviolet rays (UV) are irradiated to the adhesive layer, as the adhesiveness of the adhesive layer is relieved, the adhesive layer and the base material layer can be peeled off from the wafer with the protective layer attached.

[0118] The adhesive layer 20 may contain a pressure-sensitive adhesive, an isocyanate curing agent, and a radical initiator.

[0119] The pressure-sensitive adhesive (PSA), which acts as an adhesive that functions as a bonding substance when pressure is applied, may contain one or more known PSA adhesive components or bonding components such as rubber, acrylic resin, and silicone resin.

[0120] For example, the acrylic resin may contain an alkyl acrylate, acrylic acid, etc., but is not limited thereto.

[0121] The pressure-sensitive adhesive can show excellent adhesiveness by crosslinking or curing with the isocyanate curing agent. The isocyanate curing agent may contain one or more organic polyisocyanate compounds such as toluene diisocyanate (TDI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), xylene diisocyanate (XDI), hydrogenated toluene diisocyanate, and diphenylmethane diisocyanate.

[0122] The radical initiator generates radicals under the irradiation of energy rays, thereby starting the curing reaction caused by radical polymerization. The radical initiator can use known components without limitation.

[0123] The adhesive layer can show excellent adhesiveness to the protective layer by containing a pressure-sensitive adhesive, an isocyanate curing agent, and a radical initiator.

[0124] With respect to 100 parts by weight of the pressure-sensitive adhesive, the adhesive layer may contain 10 to 200 parts by weight of the isocyanate curing agent and 1 to 30 parts by weight of the radical initiator, but is not limited thereto.

[0125] The thickness of the adhesive layer may be 1 to 50 μm, but is not limited thereto.

[0126] The base material layer 30 is a base film for ensuring the durability and strength of the protective film sheet, and may be a relatively thick layer with excellent permeability and transparency.

[0127] The base material layer may include polyolefin resins such as polypropylene resin and polyethylene resin. The thickness of the base material layer may be 10 to 500 μm, but is not limited thereto.

[0128] The sizes of the protective layer 10, the adhesive layer 20, and the base material layer 30 constituting the protective film sheet may be the same as or different from the size of the wafer.

[0129] If the sizes of the protective layer 10, the adhesive layer 20, and the base material layer 30 are different from the size of the wafer, the size of the wafer may be the same as the size of the protective layer, but the sizes of the adhesive and base material layers may be relatively larger.

[0130] The shape of the protective film sheet may be the same as the shape of the wafer, or may be a shape including the shape of the wafer.

[0131] The protective film sheet is supplied in a state where a release film (not shown), a protective layer, an adhesive layer, and a base material layer are laminated, and can be attached to the back surface of the wafer.

[0132] As the release film, a release film well-known in the technical field to which the present invention pertains may be used. For example, a polyethylene terephthalate (PET) film, a triacetyl cellulose (TAC) film, a polynorbornene (PNB) film, a cycloolefin polymer (COP) film, a polycarbonate (PC) film, etc. may be used, but is not limited thereto.

[0133] After the cutting step of cutting the wafer, the wafer-protective layer assembly of the present invention is obtained in the single chip separation step.

[0134] In the single chip separation step, when ultraviolet rays are irradiated to the adhesive layer, the adhesive layer and the base material layer can be peeled off from the wafer with the protective layer attached as the adhesive force of the adhesive layer is relieved.

[0135] Thereby, a wafer in the shape of a semiconductor chip and a wafer-protective layer assembly with a protective layer attached can be obtained.

[0136] The wafer-protective layer assembly may be an assembly in which a protective layer is attached to one surface of the wafer and laminated at a temperature of 80°C.

[0137] In this case, when the protective layer is peeled off from the wafer at room temperature, the room temperature adhesive force of the protective layer to the wafer may be 30 to 100 gf / 25 mm.

[0138] Moreover, the 5% tensile modulus measured at room temperature of the protective layer may be 1.0 to 3.0 MPa.

[0139] Specific examples of the protective film sheet for wafers as described above are described below.

[0140] 1. Preparation of the protective film sheet for wafers

[0141] Examples and Comparative Examples

[0142] Prepare the protective layer from the protective layer compositions of Examples 1 to Comparative Example 5 by mixing according to the compositions in Tables 2 and 3 below.

[0143] Table 1

[0144]

[0145] Table 2

[0146]

[0147]

[0148] Table 3

[0149]

[0150]

[0151] 2. Physical Property Evaluation Methods and Results

[0152] 1) 5% Tensile Modulus and Elongation: Prepare a sample of the protective layer with a thickness of 75 μm, a width of 15 mm, and a length of 100 mm, and measure the tensile strength and elongation at room temperature using a universal testing machine (UTM) (ORiENTAL Co., Ltd., OTT-Sereis) under the conditions of 180° peel and 100 mm / min.

[0153] 2) Adhesion at Room Temperature: After laminating the protective layer on the adhesive surface of the process tape (PET substrate layer and acrylic adhesive layer), prepare a sample with a width of 25 mm and a length of 150 mm. After laminating the process tape, the protective layer, and the wafer at a temperature of 80°C with the wafer surface in contact with the protective layer surface, measure the adhesion at room temperature using a UTM (ORiENTAL Co., Ltd., OTT-Sereis) under the conditions of 180° peel and 100 mm / min.

[0154] 3) Reprocessability: At a temperature of 80°C, laminate the protective layer on the entire surface behind an 8-inch wafer using a mounter (Dynateck Co., Ltd., DT-MWM1030A).

[0155] Next, after laminating the reprocessing process tape (PET substrate layer and acrylic adhesive layer) on the protective layer, remove the protective layer and the process tape (PE substrate layer and acrylic adhesive layer) at room temperature.

[0156] Next, use a microscope to confirm whether there are residues on the surface behind the wafer after reprocessing. Residues are defined as those with a size of 1 μm or more.

[0157] 4) Laser marking property: Laser marking is performed under the condition of green laser and 0.5 W, and a microscope (x50) is used to confirm the recognition degree.

[0158] Examples 1 to 4 in Table 2 are samples using protective layers containing acrylic binders 1 to 3, epoxy resins 1 and 2, and curing agent 1 respectively.

[0159] The acrylic binders 1 to 3 in Examples 1 to 4 satisfy the conditions of a weight-average molecular weight of 800,000 to 1,200,000 and a Tg of 4 to 15 °C, satisfy the condition of an equivalent weight of curing agent 1 of 62 g / eq, and show a 5% tensile modulus and room-temperature adhesion at room temperature that enable reprocessing.

[0160] At the same time, the protective layer itself contains a colorant and shows excellent results in laser marking property.

[0161] On the contrary, Comparative Examples 1 to 5 in Table 3 are samples using protective layers containing acrylic binders 1, 4, 5, epoxy resins 1 and 2, and curing agent 1 or curing agent 2 respectively.

[0162] In Comparative Example 1, since the weight-average molecular weight of the acrylic binder is lower, the 5% tensile modulus at room temperature is lower, resulting in the failure of reprocessing.

[0163] In Comparative Example 2, the adhesion force increases due to the decrease in the content of the acrylic binder, resulting in the failure of reprocessing.

[0164] In Comparative Example 3, the content of phenolic epoxy resin is more than that of bisphenol epoxy resin, and the protective layer breaks due to the high 5% tensile modulus at room temperature, showing the failure of reprocessing.

[0165] In Comparative Example 4, curing agent 2 with an equivalent weight of 106 g / eq is used, and the protective layer breaks due to the high 5% tensile modulus at room temperature, showing the failure of reprocessing.

[0166] In Comparative Example 5, an acrylic binder with a low Tg is used, and the failure of reprocessing is shown as the room-temperature adhesion force increases.

[0167] As described above, the content of the present invention has been described with reference to the illustrated drawings. However, the present invention is not limited to the embodiments and drawings disclosed in this specification. It is understood that those of ordinary skill in the technical field to which the present invention pertains can implement various modifications within the scope of the technical idea of the present invention. At the same time, in the process of describing the present invention above, even if the effects of the structure of the present invention are not explicitly described, the effects that can be predicted through the relevant structure should also be recognized.

Claims

1. A protective film, characterized in that: include: substrate layer; an adhesive layer disposed on the substrate layer; and A protective layer is disposed on the adhesive layer, After the protective layer is attached to one side of the wafer at a temperature of 80° C., when the protective layer is peeled off at room temperature, the room temperature adhesive force of the protective layer to the wafer is 30 to 100 gf / 25 mm. The 5% tensile modulus of the protective layer measured at room temperature is 1.0 to 3.0 MPa.

2. The protective film according to claim 1, characterized in that: The room temperature elongation of the protective layer is greater than 100%.

3. The protective film according to claim 1, characterized in that: The protective layer comprises acrylic adhesive, epoxy resin, amine curing agent, imidazole accelerator, filler, colorant and additives.

4. The protective film according to claim 3, characterized in that: The weight average molecular weight of the acrylic adhesive is 4×10 5 ~12×10 5 g / mol.

5. The protective film according to claim 3, characterized in that: The glass transition temperature of the acrylic adhesive is 1 to 20°C.

6. The protective film according to claim 3, characterized in that: The epoxy resin includes a phenolic epoxy resin and a bisphenol epoxy resin, and the content of the phenolic epoxy resin is less than that of the bisphenol epoxy resin.

7. The protective film according to claim 3, characterized in that: The equivalent weight of the amine curing agent is less than 65 g / eq.

8. The protective film according to claim 3, characterized in that: The protective layer comprises 15 to 20 weight percent of an acrylic adhesive and 5 to 30 weight percent of an epoxy resin relative to 100 weight percent of the total.

9. The protective film according to claim 1, characterized in that: The substrate layer includes a polyolefin resin.

10. The protective film according to claim 1, characterized in that: The bonding layer comprises one or more pressure-sensitive adhesives selected from rubber, acrylic resin, and silicone resin, a curing agent, and an initiator.

11. A wafer-protective layer assembly, characterized in that: include: a wafer having semiconductor chips formed thereon; and The protective layer according to any one of claims 1 to 10, arranged on one side of the wafer, After the protective layer is attached to one side of the wafer at a temperature of 80° C., when the protective layer is peeled off at room temperature, the room temperature adhesive force of the protective layer to the wafer is 30 to 100 gf / 25 mm. The 5% tensile modulus of the protective layer measured at room temperature is 1.0 to 3.0 MPa.

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