TWI879450B - Packaging die attach film for sdbg process, manufacturing method, and using for the same - Google Patents

Abstract

A packaging die attach film, manufacturing method, and using same are provided. The packaging die attach film includes 10wt.%至22wt.% water-based resin including epoxy resin, acrylic copolymer, and silane coupling agent, and 78wt.%至90wt.% solid content metal oxide powder selected from at least one of CuO, Al ₂O ₃, ZnO or AlN. The manufacturing method includes grinding and dispersing the mixed material with three rollers, to obtain a packaging die-attached adhesive; and coating, forming, and drying the packaging die-attached adhesive to obtain a packaging die-attached adhesive film. The elongation of the packaging die-attached adhesive film is less than 100% and the mechanic stress is less than or equal to 2MPa.

Description

Packaging laminating film for SDBG process, preparation method and use method thereof

The present invention relates to a packaging film material, a preparation method thereof and a use method thereof, in particular to a packaging bonding film applied to a SDBG process, a preparation method thereof and a use method thereof.

Semiconductor packaging is the process of coating the cut dies with packaging materials after the wafers have been processed by the semiconductor front end, such as sawing, pick-up, die bonding and wire bonding, in order to protect the durability and service life of the completed integrated circuit (IC) components (such as chips) and facilitate a wide range of circuit board assembly applications.

With the popularization of the 5G era, terminal electronic products are increasingly demanding applications that are thin, light and compact. The related packaging technology is also gradually developing towards miniaturization, high density and thinness. As the current density increases, the requirements for heat dissipation and insulation increase, and the requirements for thermal conductivity of packaging materials are also gradually increasing. Furthermore, small-sized products are very prone to problems such as flying materials, water seepage, edge collapse and residual glue during the cutting process.

The existing packaging film materials are mainly filled with micron-grade SiO ₂ or Al ₂ O ₃ powder, which is used with a dicing film to cut the wafer, and then a needle is used to separate the DAF from the dicing film. However, it is difficult to effectively seal the wafer dicing tape, resulting in flying materials and water seepage during the cutting process.

In order to improve the utilization rate of wafers and simplify the conditions caused by wafer cutting, stealth cutting SDBG (Stealth Dicing Before Grinding) is further introduced into the process. Stealth cutting technology is a cutting method that focuses the laser on the inside of the wafer, forms a metamorphic layer inside the wafer, and divides the wafer into dies through methods such as expanding the adhesive film.

Accordingly, providing a packaging bonding film and a preparation method thereof for use in the SDBG process, and providing a packaging bonding film with good wafer adhesion and a brittle structure at low temperatures are important topics that the inventors of this case have devoted themselves to studying.

The main purpose of the present invention is to provide a packaging adhesive film used in the SDBG process, which has the characteristics of good adhesion to the wafer and brittle structure at low temperature. The packaging adhesive film is made of a packaging adhesive material, with a total weight of 100wt.%, and the packaging adhesive material includes: 10wt.% to 22wt.% of an aqueous resin, which includes an epoxy resin, an acrylic copolymer and a silane coupling agent; and 78wt.% to 90wt.% of a metal oxide powder with a solid content, and the metal oxide powder is selected from at least one _of CuO, _Al2O3 , ZnO or AlN or a combination thereof, and is surface-modified with a silane coupling agent; wherein the elongation of the packaging adhesive film is less than 100% and the stress is less than or equal to 2MPa.

In a specific embodiment of the present invention, the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and cyanuric acid epoxy resin or a combination thereof.

In a specific embodiment of the present invention, the acrylic copolymer is methyl methacrylate or polymethyl methacrylate.

In a specific embodiment of the present invention, the silane coupling agent is selected from at least one of methacryloxysilane, epoxysilane, isocyanate silane or a combination thereof.

In a specific embodiment of the present invention, the total weight of the water-based resin is 100wt.%, and the weight percentages of epoxy resin: silane coupling agent: acrylic copolymer are between 90-95wt.%: 3-5wt.%: 1-7wt.%.

In order to achieve the above-mentioned purpose, the present invention also provides a method for preparing a packaging adhesive film with an elongation less than 100% and a stress less than or equal to 2MPa, which comprises: mixing 10wt.% to 22wt.% of a water-based resin and 78wt.% to 90wt.% of a metal oxide powder with a solid content to obtain a mixed adhesive; grinding and dispersing the mixed adhesive with a three-roller to obtain a packaging adhesive; and coating, forming and drying the packaging adhesive to obtain a packaging adhesive film; wherein the water-based resin comprises an epoxy resin, a silane coupling agent and an acrylic copolymer, and the metal oxide powder is selected from at least one _of CuO, _Al2O3 , ZnO or AlN or a combination thereof, and is surface-modified by a silane coupling agent.

In order to achieve the above-mentioned purpose, the present invention also provides a method for using a packaging adhesive film, which includes: providing a wafer, which includes a first surface and a second surface; attaching a substrate film layer to the first surface of the wafer; performing invisible laser cutting on the second surface of the wafer to form a plurality of grains and gaps between the plurality of grains; grinding the second surface of the wafer; attaching a packaging adhesive film to the second surface of the wafer and removing the substrate film layer; and performing a film expansion and splitting step on the packaging adhesive film and the wafer at a low temperature to expand the gaps between the plurality of grains; wherein the elongation of the packaging adhesive film is less than 100% and the stress is less than or equal to 2MPa.

The packaging laminating film and its preparation method disclosed in the present invention are described in detail with reference to the specific embodiments of the present invention and the accompanying drawings. A person with ordinary knowledge in the relevant field can understand the advantages and effects of the present invention through the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention. The following implementation method will further describe the relevant technical contents of the present invention in detail, but the disclosed contents are not intended to limit the scope of protection of the present invention.

The main purpose of the present invention is to provide a packaging adhesive film used in the SDBG process, which has the characteristics of good adhesion to the wafer and brittle structure at low temperature. The packaging adhesive film is made of a packaging adhesive material. The total weight of the packaging adhesive material is 100wt.%, and the packaging adhesive material includes: 10wt.% to 22wt.% of an aqueous resin, which includes an epoxy resin, an acrylic copolymer and a silane coupling agent; and 78wt.% to 90wt.% of a metal oxide powder with a solid content, and the metal oxide powder is selected from at least _one of CuO, _Al2O3 , ZnO or AlN or a combination thereof, and is surface-modified with 1wt.% to 10wt.% of a silane coupling agent. Furthermore, the elongation of the packaging film is less than 100% and the stress is less than or equal to 2MPa.

In order to specifically compare the effects of metal oxide powders with different solid contents, Examples 1 to 2 and Comparative Examples 1 to 5 were used to prepare thermal conductive adhesives by mixing metal oxide powders with different solid contents with 20 wt.% water-based resin. The composition of the water-based resin included 90 wt.% of bisphenol F-type epoxy resin, 3 wt.% of epoxy silane coupling agent, and 7 wt.% of methyl methacrylate. Elongation, stress, and crack tests were performed, and the results are shown in Table 1.

Table 1 Test Solid content (wt.%) Elongation(%) Stress(MPa) Split operability test Embodiment 1 80 30 0.9 OK Embodiment 2 78 95 2 OK Comparison Example 1 75 200 2 NG Comparison Example 2 70 450 1 NG Comparison Example 3 65 530 3 NG Comparison Example 4 60 610 4 NG Comparison Example 5 50 770 8 NG

As shown in Table 1, under the same ratio of water-based resin, the solid content ratio of metal oxide powder affects the feasibility of product splitting operation. Generally speaking, when using high solid content metal oxide powder for mixed production, it is easy to produce powder that is difficult to disperse evenly and easy to agglomerate. The oxide powder filler of the present invention is first placed in a silane coupling agent for surface modification, which can improve the compatibility of the resin and the metal oxide powder and reduce the generation of powder agglomeration. Under the ratio of 78wt.% to 90wt.% solid content of metal oxide powder, the elongation can be less than 100% and the stress can be greater than or equal to 2MPa.

Preferably, the metal oxide powder is selected from at least one of CuO, Al ₂ O ₃ , ZnO or AlN or a combination thereof. More preferably, the metal oxide powder is selected from CuO ₃ or ZnO.

Epoxy resin has excellent electrical properties, low curing shrinkage, low volatile byproducts, high temperature resistance, solvent resistance and other characteristics, and is widely used as a packaging material for semiconductor components.

In a specific embodiment of the present invention, the epoxy resin used in the present invention is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and cyanuric acid epoxy resin or a combination thereof. Preferably, the epoxy resin of the present invention is bisphenol F epoxy resin. Specifically, bisphenol F epoxy resin is also called bisphenol F diglycidyl ether, abbreviated as BPF, which has the characteristics of low viscosity, corrosion resistance, adhesion, thermal stability and insulation.

Silane coupling agents are compounds composed of organic matter and silicon. The molecules of silane coupling agents have two or more different reactive groups, which can react chemically with inorganic materials and organic materials. Specifically, the silane coupling agent of the present invention can improve the bonding between copper oxide and epoxy resin, avoid defects such as holes at the interface, and maintain better thermal conductivity.

In a specific embodiment of the present invention, the silane coupling agent is selected from at least one of methacryloxysilane, epoxysilane, isocyanate silane or a combination thereof. More specifically, the silane coupling agent of the present invention can be a commercially available product. For example, the methacryloxysilane can be a combination of 3-methacryloxypropyl and other silanes, such as methyldimethoxysilane, trimethoxysilane, methyldiethoxysilane and triethoxysilane; the epoxysilane can be 2-(3,4-epoxyhexylethyltrimethoxysilane, (3-glycidoxypropyl)trimethoxysilane, (3-glycidoxypropyl)methyldiethoxysilane and (3-glycidoxypropyltriethoxysilane; the isocyanate silane can be 3-isocyanatepropyltriethoxysilane.

In order to specifically compare the difference in thermal conductivity of the thermally conductive adhesives prepared by the silane coupling agents selected in the present invention, a metal oxide powder with a solid content of 80 wt.% was mixed with 20 wt.% of a water-based resin to prepare thermally conductive adhesive Examples 4 to 6. The composition of the water-based resin was bisphenol F-type epoxy resin and methyl methacrylate. A roughness test was performed. The composition and ratio of the water-based resin are shown in Table 2.

Table 2 Items Silane coupling agent Metal oxide powder solid content (wt.%) Bisphenol F epoxy resin (wt.%) Acrylic acid copolymer (wt.%) Silane coupling agent (wt.%) Roughness(μm) Embodiment 3 Methacryloylsilane 80 10 5 5 1.06 Embodiment 4 Epoxysilane 80 10 5 5 0.53 Embodiment 5 Isocyanate silane 80 10 5 5 0.85

See Table 3, epoxysilane can show the best roughness. More specifically, the packaging bonding film made with (3-glycidoxypropyl)trimethoxysilane can show the best roughness. If the roughness is too large, it means that the powder is not evenly dispersed, which will lead to poor adhesion between DAF and wafer, affecting the cracking situation.

The acrylic copolymer may be a resin polymer derived from an acrylic monomer, which may be selected from methyl acrylate, ethyl acrylate, n-butyl acrylate, methyl methacrylate, n-butyl methacrylate, etc. The acrylic resin may be selected from a thermosetting acrylic resin or a thermoplastic acrylic resin as required.

Specifically, thermosetting acrylic resin is an infusible acrylic polymer with acrylic monomers as the basic components and cross-linked into a network structure. In addition to the general properties of acrylic resin, it has better heat resistance, water resistance, solvent resistance, wear resistance, and scratch resistance (anti-scratch resistance), and has a variety of forms such as bulk casting materials, solution type, emulsion type, and water-based type. More specifically, thermoplastic acrylic resin is a type of thermoplastic resin made by polymerizing acrylic acid, methacrylic acid and its derivatives (such as esters, nitriles, and amides). It can be repeatedly softened by heat and solidified by cooling. It is generally a linear polymer compound, which can be a homopolymer or a copolymer, with good physical and mechanical properties, excellent weather resistance, chemical resistance and water resistance, and high gloss and color retention. The molecular weight of thermoplastic acrylic resin used in the coating industry is generally 75,000 to 120,000. Cellulose nitrate, cellulose acetate butyrate and perchloroethylene resin are often used together with it to improve the coating performance. Thermoplastic acrylic resin is a type of solvent-type acrylic resin. It can be melted and dissolved in a suitable solvent. The coating prepared by it forms a film by the aggregation of macromolecules after the solvent evaporates. No cross-linking reaction occurs during film formation, and it is a non-reactive coating. In order to achieve better physical and chemical properties, the molecular weight of the resin should be increased, but in order to ensure that the total amount of non-volatile substances is not too low and the molecular weight is not too large, generally at a molecular weight of tens of thousands, the physical and chemical properties and construction performance are more balanced.

In the embodiments of the present invention, the acrylic copolymer may be methyl methacrylate (MMA) or poly methyl methacrylate (PMMA).

The water-based resin used in the present invention includes epoxy resin, silane coupling agent and acrylic copolymer. In a specific embodiment of the present invention, the water-based resin has a specific ratio, with the total weight of the water-based resin being 100wt.%, the weight percentage of epoxy resin: silane coupling agent: acrylic copolymer is between 90-95wt.%: 3-5wt.%: 1-7wt.%.

In order to specifically compare the difference in surface roughness of the water-based resin formulation of the present invention, a metal oxide powder with a solid content of 80% was mixed with 20wt.% of a water-based resin to prepare thermal conductive adhesive Examples 6 to 14. The composition of the water-based resin selected bisphenol F type epoxy resin, epoxy silane coupling agent (KBM-403) and acrylic copolymer (methyl methacrylate), and the surface roughness (Ra) test was performed. The composition ratio and roughness of the water-based resin are shown in Table 3.

Table 3 Embodiment Epoxy resin (wt.%) Silane coupling agent (wt.%) Acrylic acid copolymer (wt.%) Surface roughness(μm) 6 90 1 9 0.46 7 90 3 7 0.38 8 90 5 5 0.53 9 92 1 7 0.68 10 92 3 5 0.76 11 92 5 3 0.59 12 94 1 5 0.66 13 94 3 3 0.87 14 94 5 1 0.73

It can be seen from Table 3 that the ratio of Example 7 has better roughness. Optimally, the weight percentage of epoxy resin: silane coupling agent: acrylic copolymer is 90 wt.%: 3 wt.%: 7 wt.%.

In order to achieve the above-mentioned purpose, the present invention further provides a method for preparing a packaging laminating film. Referring to FIG. 1 , it shows steps S102 to S106 of the method for preparing a packaging laminating film of the present invention.

S102: Mix 10wt.% to 22wt.% of a water-based resin and 78wt.% to 90wt.% of a metal oxide powder with a solid content to obtain a mixed rubber material. The water-based resin includes an epoxy resin, _a silane coupling agent and an acrylic copolymer. The selection of these components is as described in the specification of the present invention and will not be repeated here. More specifically, the metal oxide powder of the present invention is selected from at least one of CuO, _Al2O3 , ZnO or AlN or a combination thereof, and is surface-modified by a silane coupling agent. Through the surface modification, the compatibility of the resin and the metal oxide powder particles is increased, the generation of powder agglomeration is reduced, and the roughness of the finished product is effectively reduced.

S104 grinds and disperses the mixed adhesive material with a three-drum grinder to obtain a packaging adhesive material. The three-drum grinder uses three parallel drums that rotate in opposite directions and at different speeds to generate shear force, thereby achieving the purpose of mixing, refining, dispersing, or making the viscosity of the object uniform.

S106: coating, forming and drying the packaging adhesive material to obtain a packaging adhesive film.

Furthermore, the present invention also provides a method for using the packaging laminating film, comprising:

S201 provides a wafer, which includes a first surface and a second surface;

S202 attaching a substrate film layer to the first surface of the wafer;

S203: performing invisible laser cutting on the second surface of the wafer to form a plurality of dies and gaps between the plurality of dies;

S204: grinding the second surface of the wafer;

S205: attaching a packaging film to the second surface of the wafer and removing the substrate film layer; and

S206: performing a film expansion and splitting step on the packaging bonding film and the wafer at a low temperature to expand the gap between the plurality of dies.

One of the beneficial effects of the present invention is that the packaging bonding film provided by the present invention for use in the SDBG process has a specific composition and formula ratio of "10wt.% to 22wt.% of a water-based resin, which includes an epoxy resin, a silane coupling agent and an acrylic copolymer; and 78wt.% to 90wt.% of a metal oxide powder with a solid content" to obtain a packaging bonding film with an elongation less than 100% and a stress less than or equal to 2MPa.

Furthermore, the composition and formula ratio of the present invention effectively reduce the roughness of the packaging laminating film prepared by the present invention. Moreover, the packaging laminating film of the present invention improves the fluidity of the metal oxide powder and increases the contact area, thereby increasing the solid content of the metal oxide powder in the composition.

Furthermore, the packaging laminating film and the preparation method thereof of the present invention effectively improve the powder contact, reduce powder agglomeration and reduce the surface roughness of the laminating film, so as to avoid flying materials, water seepage and the like in the subsequent cutting process.

In addition, the packaging film of the present invention has excellent wafer adhesion, can effectively maintain the alignment of the die, and has the characteristics of being brittle at low temperatures, and is suitable for application in the SDBG process. The method of using the packaging film of the present invention utilizes invisible laser cutting to expand the film and split it at low temperature, thereby improving the problems of flying materials, water seepage, and burrs generated in the wafer dicing process.

The above description is only a preferred specific example of the present invention, and does not limit the patent scope of the present invention. Therefore, all equivalent changes made by applying the contents of the present invention are also included in the scope of the present invention and are appropriately stated.

S102~S106: Steps S201~S206: Steps

FIG1 is a flow chart of a method for preparing a packaging laminating film of the present invention; and

FIG. 2 is a flow chart of the method for using the packaging laminating film of the present invention.

S102~S106: Steps

Claims (9)

A packaging bonding film used in SDBG process is made of a packaging bonding adhesive, with the total weight of the packaging bonding adhesive being 100wt.%, the packaging bonding adhesive comprising: 10wt.% to 22wt.% of a water-based resin, which comprises an epoxy resin, an acrylic copolymer and a silane coupling agent; and 78wt.% to 90wt.% of a metal oxide powder with a solid content, and the metal oxide powder is selected from at least one of CuO, _Al2O3 , _ZnO or AlN or a combination thereof, and has been surface-modified with 1wt.% to 10wt.% of a silane coupling agent; wherein the elongation of the packaging bonding film is less than 100% and the stress is less than or equal to 2MPa. As described in claim 1, the packaging laminating film used in the SDBG process, wherein the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and cyanuric acid epoxy resin or a combination thereof. The packaging laminating film used in the SDBG process as described in claim 1, wherein the acrylic copolymer is methyl methacrylate or polymethyl methacrylate. As described in claim 1, the packaging bonding film used in the SDBG process, wherein the silane coupling agent is selected from at least one of methacryloyloxysilane, epoxysilane, isocyanate silane or a combination thereof. As described in claim 1, the packaging laminating film used in the SDBG process, wherein the total weight of the water-based resin is 100wt.%, and the weight percentages of the epoxy resin: silane coupling agent: acrylic copolymer are between 90~95wt.%: 3~5wt.%: 1~7wt.%. A method for preparing a packaging adhesive film for use in a SDBG process comprises: mixing 10wt.% to 22wt.% of a water-based resin and 78wt.% to 90wt.% of a metal oxide powder with a solid content to obtain a mixed adhesive; grinding and dispersing the mixed adhesive with a three-roller to obtain a packaging adhesive; and coating, forming and drying the packaging adhesive to obtain a packaging adhesive film; wherein the water-based resin comprises an epoxy resin, a silane coupling agent and an acrylic copolymer, and the metal oxide powder is selected from at least one of CuO, _Al2O3 , ZnO or AlN or a combination thereof, and is surface-modified with a silane coupling agent; wherein the elongation of the packaging adhesive film is less than 100% and the stress is less _than or equal to 2MPa. The method for preparing a packaging laminating film as described in claim 6, wherein the epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and cyanuric acid epoxy resin or a combination thereof; the silane coupling agent is selected from at least one of methacryloyloxysilane, epoxysilane and isocyanate silane or a combination thereof. The preparation method of the packaging laminating film as described in claim 6, wherein the total weight of the water-based resin is 100wt.%, and the weight percentage of the epoxy resin: silane coupling agent: acrylic copolymer is between 90~95wt.%: 3~5wt.%: 1~7wt.%. A method for using a packaging adhesive film comprises: providing a wafer comprising a first surface and a second surface; attaching a substrate film layer to the first surface of the wafer; performing invisible laser cutting on the second surface of the wafer to form a plurality of dies and gaps between the dies; grinding the second surface of the wafer; attaching a packaging adhesive film to the second surface of the wafer and removing the substrate film layer; and performing an expansion film splitting step on the packaging adhesive film and the wafer at a low temperature to expand the plurality of dies. The invention relates to a method for preparing a packaging adhesive film, wherein the packaging adhesive film has an elongation of less than 100% and a stress of less than or equal to 2MPa; wherein the packaging adhesive film is made of a packaging adhesive material, and the total weight of the packaging adhesive material is 100wt.%, and the packaging adhesive material comprises: 10wt.% to 22wt.% of an aqueous resin, which comprises an epoxy resin, an acrylic copolymer and a silane coupling agent; and 78wt.% to 90wt.% of a metal oxide powder with a solid content, and the metal oxide powder is selected from _at least one of CuO, _Al2O3 , ZnO or AlN or a combination thereof, and is surface-modified with 1wt.% to 10wt.% of a silane coupling agent.

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