Liquid insulating material having flowability, leveling properties, and flexibility

Abstract

The present invention relates to a liquid insulating material and, more particularly, to a liquid insulating material comprising: an epoxy main material including a solid epoxy resin having a softening point of at most 150 °C and an epoxy equivalent weight of 850-1500 g / eq and a liquid epoxy resin having an epoxy equivalent weight of at most 500 g / eq; a curing agent having a softening point of at most 125 °C; and an inorganic filler consisting of at least two types of inorganic particles having different average particle sizes, the liquid insulating material having flowability, leveling properties, and flexibility by controlling gel time.

Description

Liquid insulating material with flowability, leveling properties and flexibility

[0001] The present invention relates to a liquid insulating material having flowability, leveling property and flexibility, and more particularly, to a liquid insulating material having flowability, leveling property and flexibility through gel time control.

[0002] Typically, the primary binders for liquid insulating materials used in semiconductor and electrical / electronic component packaging are epoxy and silicone resin-based liquid composite insulating materials. Epoxy resin-based liquid insulating materials are widely used due to their unique properties, such as excellent substrate adhesion and chemical resistance. Semi-cured and dry (B-stage) solid epoxy insulating materials are the dominant type of insulating materials for semiconductor packaging. While these materials are generally suitable for batch packaging processes, their application in packaging processes such as continuous wet coating, printing, and filling required in reel-to-reel processes is limited.

[0003] In particular, for the reel-to-reel continuous packaging process to be feasible, the packaging material must be liquid, and sufficient fluidity must be maintained during the drying process after printing and coating to ensure effective filling and surface leveling. Furthermore, securing flexibility in the metal substrate used in the reel-to-reel process and imparting flexibility to the resin printed and filled on the substrate are required. However, the rigid properties of solid packaging materials used in conventional batch processes, such as semi-curing and drying, limit flexibility.

[0004] To improve this flexibility, a high-equivalent epoxy resin formulation can be applied. However, this high-equivalent resin has a high softening point, which causes overdrying and rapid drying when the solvent evaporates, which greatly limits the flowability of the filling and printing film, resulting in many problems such as underfilling during the substrate filling process. This can cause fatal defects such as the formation of pores inside and on the surface of the substrate insulating film. In other words, not only can the internal pores themselves be a fatal problem for durability, but they also cause a decrease in adhesion with the metal substrate, which leads to a problem of a decrease in adhesive strength and cohesion, which are key required properties for semiconductor durability.

[0005] On the other hand, low-softening-point resins have the problem of flowing out in the vertical drying zone, which is the opposite of the high-softening-point resins. This flowing out causes non-uniform thickness of the insulating film in semiconductor substrate packaging. Therefore, gel time control is required to prevent flowing out in the vertical drying zone in continuous processing.

[0006] Accordingly, the inventors of the present invention have developed a liquid insulating material that can improve flowability and leveling properties while securing flexibility in a substrate bending process, while preventing the flow-off phenomenon of low-softening-point resins and solving the problems of overdrying and filling with internal defects that occur when using solid materials and high-softening-point resins, and have completed the present invention.

[0007] Accordingly, the present invention has as its technical solution the task of providing a liquid insulating material having flowability, leveling properties and flexibility through gel time control.

[0008] In order to solve the above technical problem, the present invention,

[0009] A liquid insulating material is provided, comprising an epoxy resin comprising a solid epoxy resin having a softening point of at most 150°C and an epoxy equivalent of 850 to 1500 g / eq and a liquid epoxy resin having an epoxy equivalent of at most 500 g / eq; a hardener having a softening point of at most 125°C; and an inorganic filler comprising at least two types of inorganic particles having different average particle sizes; characterized in that the material has flowability, leveling properties, and flexibility by controlling the gel time.

[0010] In the present invention, the epoxy resin is characterized in that it contains a solid epoxy resin and a liquid epoxy resin in a weight ratio of 50 to 80:10 to 50.

[0011] In addition, in the present invention, the solid epoxy resin or liquid epoxy resin is characterized in that it is at least one selected from among bisphenol-based epoxy resin, biphenyl-based epoxy resin, naphthalene-based epoxy resin, fluorene-based epoxy resin, novolac-based epoxy resin, phenol novolac-based epoxy resin, cresol novolac-based epoxy resin, pentadiene-based epoxy resin, dicyclopentadiene-based epoxy resin, trishydroxylphenylmethane-based epoxy resin, and tetraphenylmethane-based epoxy resin.

[0012] In addition, in the present invention, it is characterized in that the inorganic filler is included in an amount of 70 to 90% of the total weight of the insulating material.

[0013] In addition, in the present invention, the inorganic filler is characterized in that it includes inorganic particles having an average particle size of 25 to 40 ㎛ and inorganic particles having an average particle size of 5 to 20 ㎛ in a weight ratio of 60:40 to 80:20.

[0014] In addition, in the present invention, the inorganic filler is characterized in that it is two or more kinds selected from the group consisting of natural silica, fused silica, amorphous silica, hollow silica, aluminum hydroxide, boehmite, magnesium hydroxide, molybdenum oxide, zinc molybdate, zinc borate, zinc stannate, aluminum borate, potassium titanate, magnesium sulfate, silicon carbide, zinc oxide, boron nitride (BN), silicon nitride, silicon oxide, aluminum titanate, barium titanate, barium strontium titanate, aluminum oxide, alumina, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, glass fibers, and mixtures thereof.

[0015] In addition, in the present invention, the liquid insulating material is characterized by having a gel time of 90 to 240 seconds at 125 to 150°C.

[0016] In addition, in the present invention, the insulating material is characterized in that it is for packaging of a semiconductor, a semiconductor substrate, or an electrical or electronic component.

[0017] The liquid insulating material according to the present invention is configured to have a softening point below the reel-to-reel drying process temperature in terms of the composition of the epoxy main material and the hardener, and to have sufficient flowability and leveling properties in the filling, printing, and drying processes by varying the particle size of the inorganic filler, while also ensuring flexibility during the substrate bending process, thereby simultaneously having properties such as gel time control, improved flowability, improved leveling properties, and bending flexibility, and thus has the effect of being applicable to continuous processes for packaging semiconductors, semiconductor substrates, and electronic components. Accordingly, packaging without internal and surface defects is possible, and sufficient flowability and leveling properties are exhibited to improve substrate adhesion, bonding strength, and density, while also enhancing the durability and applicability of semiconductor substrates through improved bending flexibility.

[0018] Figure 1 shows an SEM photograph of a cross-section of an insulating film formed with a liquid insulating material according to one embodiment of the present invention (a: Example 1, b: Comparative Example 1)

[0019]

[0020] The present invention is described in detail below.

[0021] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0022] The terminology used herein is solely for the purpose of describing specific embodiments and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. Furthermore, throughout the specification, when a part is said to "include" a component, unless otherwise specifically stated, this does not exclude other components but rather implies the inclusion of additional components.

[0023]

[0024] In one aspect, the present invention relates to a liquid insulating material, comprising an epoxy resin comprising a solid epoxy resin having a softening point of at most 150°C and an epoxy equivalent of 850 to 1500 g / eq, and a liquid epoxy resin having an epoxy equivalent of at most 500 g / eq; a hardener having a softening point of at most 125°C; and an inorganic filler comprising at least two types of inorganic particles having different average particle sizes, characterized in that the material has flowability, leveling properties, and flexibility by controlling the gel time.

[0025] The present invention controls the epoxy equivalent and softening point of the epoxy base material and the softening point of the hardener that crosslinks the epoxy base material, thereby controlling the gel time and over-drying in the packaging process using an insulating material, thereby improving the leveling property so that the flowability suitable for the packaging process and the filling by the insulating material can be sufficiently achieved, while simultaneously securing flexibility.

[0026] In the present invention, the epoxy resin plays a major role in controlling gel time and over-drying, as well as controlling flexibility. The epoxy resin is characterized in that it contains a solid epoxy resin and a liquid epoxy resin in a weight ratio of 50 to 80:10 to 50.

[0027] That is, the solid epoxy resin is preferably used at 50 to 80 wt% in terms of the epoxy resin content, with an equivalent weight of 850 to 1500 g / eq. This is because the solid epoxy resin imparts mechanical properties such as flexibility and toughness to the insulating film of the insulating material, while also providing process characteristics that prevent the insulating material from flowing down during the packaging process. If it is included below the above range, the flowability may be excessive, resulting in a flowing down phenomenon, and if it exceeds the above range, there is a problem in that the insulating material is not sufficiently filled due to overdrying and rapid drying, resulting in defects such as unfilled pores.

[0028] In addition, the liquid epoxy resin is preferably an epoxy resin having an epoxy equivalent of up to 500 g / eq, and is included in an epoxy-based ratio of 10 to 50 wt%. When the liquid epoxy resin is included in the above range, overdrying due to the solid high equivalent epoxy resin is controlled, and flowability is controlled while preventing flowing, thereby improving leveling properties, so that the insulating material is sufficiently filled, thereby preventing the occurrence of defects such as pores.

[0029] In addition, it is important that the solid epoxy resin has an equivalent weight of 850 to 1500 g / eq and a softening point of at most 150°C. Preferably, the softening point does not exceed at most 125°C. This is because when a solid epoxy resin having a softening point higher than 150°C is prescribed together with a liquid low-equivalent epoxy resin, although the drying conditions may be satisfied in the packaging process of the insulating material, problems such as warping and lack of flexibility may occur.

[0030] In addition, the solid epoxy resin or liquid epoxy resin constituting the epoxy resin may include at least one selected from bisphenol-based epoxy resin, biphenyl-based epoxy resin, naphthalene-based epoxy resin, fluorene-based epoxy resin, novolac-based epoxy resin, phenol novolac-based epoxy resin, cresol novolac-based epoxy resin, pentadiene-based epoxy resin, dicyclopentadiene-based epoxy resin, trishydroxylphenylmethane-based epoxy resin, and tetraphenylmethane-based epoxy resin. The epoxy resin may also be an epoxy resin having a functional group, and those commonly used in resin compositions for semiconductor packages may be used without limitation, and the type thereof is not limited.

[0031] In addition, the liquid epoxy resin may be an epoxy resin that includes an aliphatic repeating unit in the main chain forming the epoxy backbone. Including an aliphatic repeating unit in the main chain as mentioned above means that the main chain is composed only of aliphatic repeating units, or that a long-chain aliphatic repeating unit is included in the main chain. As the long-chain aliphatic repeating unit, it is preferable to include at least one polymer structure selected from the group consisting of a long-chain alkyl such as polyethylene, polypropylene, or polybutadiene; a long-chain alkyl glycol such as polyethylene glycol (PEG) or polypropylene glycol (PPG); a (meth)acrylic acid ester such as ethylhexyl (meth)acrylate, butyl (meth)acrylate, n-octyl (meth)acrylate, or n-dodecyl (meth)acrylate; vinyl acetate, and styrene, but is not limited thereto. The above epoxy resin can be maintained in a film form without breaking or the like before curing, forms a crosslinked structure during the curing process, and has viscoelasticity even after becoming a crosslinked body, thereby providing flexibility.

[0032] In addition, in the present invention, the curing agent for the curing reaction with the epoxy resin is not limited to a solid or liquid state, but a solid resin is more preferable. At this time, the curing agent is a factor that affects the flowability and gel time during continuous process filling, so it is important to appropriately control the softening point. Therefore, the curing agent having a softening point of 60°C or higher, or 60°C to 150°C, or 105°C to 150°C, or 70°C to 125°C can be preferably applied. A curing agent having a softening point of 60°C or higher can have sufficient heat resistance, strength, and adhesiveness after curing, but if the softening point of the curing agent is too high, the fluidity of the insulating material decreases, causing pores to form in the insulating film, which can significantly deteriorate the quality. Therefore, the softening point is preferably 125°C at most. The curing agent may include one or more compounds selected from the group consisting of an amine-based curing agent, a phenol-based curing agent, and an acid anhydride-based curing agent. At this time, a novolak phenol resin can be preferably applied as the phenol curing agent. The novolak phenol resin has a chemical structure in which a ring is positioned between reactive functional groups. Due to this structural characteristic, the novolak phenol resin can further reduce the hygroscopicity of the insulating material and further increase stability in the process, thereby playing a role in preventing peeling or cracking. Specific examples of the novolak phenol resin include at least one selected from the group consisting of novolak phenol resin, xyloc novolak phenol resin, cresol novolak phenol resin, biphenyl novolak phenol resin, bisphenol A novolak phenol resin, and bisphenol F novolak phenol resin.

[0033] In addition, the above liquid insulating material may further include a curing catalyst such as phosphorus, amine, or cyanide to promote curing.

[0034] In addition, the liquid insulating material may further include a functional resin such as a silicone-modified epoxy resin, a urethane-modified epoxy resin, a rubber-modified epoxy resin, a polyol, or a phenol to impart mechanical properties such as flexibility and toughness to the insulating film. In this case, it is preferable that the functional resin be included in an amount of 5 to 10 wt% of the epoxy main material.

[0035] In addition, the liquid insulating material of the present invention comprises an inorganic filler composed of at least two types of inorganic particles having different average particle sizes. By configuring the particles to have different average particle sizes, flowability can be controlled, thereby delaying or controlling the gel time. Accordingly, the problem of flowability being hardly controlled and gel time being shortened when the average particle size is composed of only a single type of inorganic particle is solved.

[0036] Preferably, the inorganic filler is included in an amount of 70 to 90% of the total weight of the insulating material. If the content of the inorganic filler is less than 70% by weight, the insulating material cannot sufficiently provide its insulating performance, and if it exceeds 90% by weight, the mechanical properties of the insulating film, such as adhesion and flexibility, deteriorate, which is not preferable.

[0037] In addition, preferably, the inorganic filler may include inorganic particles having an average particle size of 25 to 40 μm and inorganic particles having an average particle size of 5 to 20 μm in a weight ratio of 60:40 to 80:20. When the particles are composed in the above range and particle size distribution, the flowability can be improved when filling to a thickness of 200 μm in the packaging process, while the gel time can be controlled to suit the process, and an insulating film without defects such as internal pores can be formed, thereby imparting leveling properties to the liquid insulating material.

[0038] At this time, the type of the inorganic particles is not particularly limited, but may be at least one selected from the group consisting of natural silica, fused silica, amorphous silica, hollow silica, aluminum hydroxide, boehmite, magnesium hydroxide, molybdenum oxide, zinc molybdate, zinc borate, zinc stannate, aluminum borate, potassium titanate, magnesium sulfate, silicon carbide, zinc oxide, boron nitride (BN), silicon nitride, silicon oxide, aluminum titanate, barium titanate, barium strontium titanate, aluminum oxide, alumina, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, single glass fibers, and mixtures thereof. Among these, silica particles capable of imparting electrical insulation can be particularly preferably used. When providing both electrical insulation and high heat dissipation properties, alumina, silicon carbide, and boron nitride can be particularly preferably used.

[0039] Preferably, the liquid insulating material is characterized by a gel time of 90 to 240 seconds at 125 to 150°C. If the gel time is longer than the above range, there is a problem of flow occurring during the process, and if the gel time is shorter than the above range, problems such as formation of pores due to overdrying and rapid drying may occur. Therefore, when the gel time is controlled within the above range, the liquid insulating material can be effectively filled and surface leveled through sufficient flowability during the drying process after printing and coating in the reel-to-reel continuous packaging process.

[0040] In addition, the liquid insulating material of the present invention may further include additives for purposes such as dispersion, adhesion, and coloring of the packaging insulating material, in addition to the above-described epoxy resin, curing agent, and inorganic filler. Preferably, the additives may be included in an amount of 1 to 5 wt% based on 100 wt% of the liquid insulating material.

[0041] In this way, the liquid insulating material of the present invention can be particularly applied to packaging semiconductors, semiconductor substrates, or electrical and electronic components.

[0042] The liquid insulating material of the present invention can be manufactured by comprising an epoxy resin, a curing agent for curing the epoxy resin, a curing catalyst, an inorganic filler, other additives, and a solvent. Specifically, the method can include the steps of: mixing a solid epoxy resin and a curing agent in a dilution solvent to manufacture a solvent-diluted solid epoxy resin and a solvent-diluted curing agent, respectively; mixing the solvent-diluted solid epoxy resin and the liquid epoxy resin to manufacture an epoxy resin; mixing the epoxy resin and the solvent-diluted curing agent at an equivalent ratio of 1:1, and further mixing a curing catalyst and additives to manufacture a liquid material; and adding an inorganic filler to the liquid material to manufacture a liquid insulating material.

[0043] Preferably, the solvent may be one that is commonly used in a resin composition for packaging such as a semiconductor, and the type thereof is not particularly limited. Specific examples of the solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; glycol ethers (cellosolve) such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol diethyl ether and triethylene glycol monoethyl ether; Examples thereof include acetic acid esters such as ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, and dipropylene glycol monomethyl ether acetate; alcohols such as ethanol, propanol, ethylene glycol, propylene glycol, and carbitol; aliphatic hydrocarbons such as octane and decane; petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha; and amides such as dimethylacetamide and dimethylformamide (DMF). These solvents can be used alone or as a mixture of two or more.

[0044] The liquid insulating material manufactured as described above is configured to have a softening point below the reel-to-reel drying process temperature in terms of the composition of the epoxy main material and the hardener, and the particle size of the inorganic filler is varied so as to have sufficient flowability and leveling properties in the filling, printing, and drying processes, while also ensuring flexibility in the substrate bending process, thereby simultaneously having characteristics such as gel time control, improved flowability, improved leveling properties, and bending flexibility, and can be particularly applied to continuous processes for packaging semiconductors, semiconductor substrates, and electronic components.

[0045]

[0046] Hereinafter, the present invention will be described in detail with examples, but the present invention is not limited thereto.

[0047]

[0048] <Examples 1-5>

[0049] Preparation of materials

[0050] High-equivalent weight epoxy resin: Oline's DER 6155 (EEW ​​1,250-1,400, softening point 105-125℃, solid) / DER 654UE (EEW ​​860-930, softening point 104-110℃, solid)

[0051] Low-equivalent weight epoxy resin: DER 732 (EEW ​​320, liquid) from Oline

[0052] Hardener: TD2093Y from DIC (OH EW 104, softening point 100℃, solid),

[0053] Inorganic particles: Sibelco's SS0140 (average particle size 14㎛), SS0300 (average particle size 30㎛) particles

[0054] Other additives: dispersant (Antiterra U from BYK), antifoam (BYK-A-535)

[0055]

[0056] Manufacturing of liquid insulating materials

[0057] The above-prepared solid epoxy resin and hardener were mixed with the dilution solvent Butyl carbitol to adjust the solid content to 50%, and stirred at 60°C for 3-4 hours to prepare solvent-diluted solid epoxy resin and hardener, respectively. Thereafter, the solvent-diluted epoxy resin and liquid epoxy resin were mixed at a predetermined weight ratio to prepare an epoxy resin matrix.

[0058] The above-mentioned epoxy resin and solid curing agent were mixed in an equivalent ratio of 1:1, and 2-methylimidazole as a curing catalyst and additives including a dispersant, a colorant, and an antifoaming agent were mixed, and then stirred at room temperature for 30 minutes to prepare a liquid material. At this time, the curing catalyst was added so as to be 0.1 wt% of the mixed weight of the epoxy resin and the curing agent, and the curing catalyst and additives were further mixed so as to be 5 wt% based on 100 wt% of the total liquid material.

[0059] Afterwards, a silica filler was added to the liquid material mixed with an epoxy resin, a curing agent, a curing catalyst, and additives to produce a liquid insulating material. At this time, the added silica filler accounted for 88 wt% of the total 100 wt% of the liquid insulating material, and the remaining liquid material accounted for 12 wt%. In addition, when adding the silica filler, SS0140 and SS0300 were mixed in a weight ratio of 6:4.

[0060] In addition, when manufacturing the above liquid insulating material, the liquid material and silica filler were mixed and then a paste dispersing device was used to ensure effective dispersion without agglomeration.

[0061] For the liquid insulating material manufactured above, the viscosity of the liquid insulating composite material can be adjusted by adding additional solvent depending on the thickness required during the manufacturing process, and the viscosity range is not limited. The typical viscosity of the final manufactured liquid insulating material was determined to be approximately 5,000 to 10,000 cps at room temperature.

[0062]

[0063] Comparative Examples 1-5

[0064] A liquid insulating material was manufactured in the same manner as in the above example, but by changing the mixing ratio of the epoxy resin, using an epoxy resin with a different epoxy equivalent, using a hardener with a high softening point, or mixing only one type of inorganic filler. The materials additionally used at this time are as follows.

[0065] High equivalent weight epoxy resin: Comparative Example 1 - DER 668-20 (EEW ​​2,000-3,500, softening point 135-146℃, solid), Comparative Example 2 - YD-019K (EEW ​​2,400-3,800, softening point 135℃, solid)

[0066] Hardener (Comparative Examples 1 and 3): KH60221 from DIC (OH EW 118, softening point 125-140°C, solid)

[0067] Inorganic filler (Comparative Example 5): SS0300 particles from Sibelco

[0068]

[0069] Table 1 below shows the mixing ratios of Examples 1 to 5 and Comparative Examples 1 to 5.

[0070] Liquid materialInorganic filler(%)Epoxy main additive(%)Curing agentHigh equivalent weight epoxy(%)Low equivalent weight epoxy(%)Softening point≥125℃<125℃<125℃-≥125℃<125℃Type 1Type 2Equivalent weight(eew)1500 or more1000~1500850~1000Less than 500-----ShapeSolidSolidSolidLiquidLiquidSolidSolidExample 165305ooExample 280155ooExample 365305ooExample 480155ooExample 54040155ooComparative example 180155ooComparative example 280155ooComparative example 395-5ooComparative example 495-5ooComparative example 595-5oo

[0071]

[0072] <Example of an exam>

[0073] The properties of the insulating film manufactured from the liquid insulating material manufactured in Examples 1 to 5 and Comparative Examples 1 to 5 were measured by the following method.

[0074] - Presence of pores: Observed using an electron microscope (SEM) and measured whether they exist inside and outside the packaging film (Presence: O, No pores: X)

[0075] - Gel time (@125℃): 4 minutes or more (L, long), 2-4 minutes (M, process suitable), 2 minutes or less (S, short)

[0076] - Flexibility: Cracks occur when banding 200㎛ thick manufactured film (200mm*50mm). Film end-to-end length: 10cm or more (poor), 5-10cm (average), 5cm or less (excellent).

[0077] - Warpage: After 200um coating process on copper substrate (0.3t), degree of shrinkage (lifting) of 100mm*100mm corner: 1mm or less (excellent), 1-3mm (average), 3mm or more (poor)

[0078]

[0079] The measurement results according to the test examples are shown in Table 2 below, and the cross-sections of the films formed according to Example 1 and Comparative Example 1 are shown in Fig. 1.

[0080] Physical properties, air permeability, gel time, flexibility, warpage, example 1xM, excellent, excellent example 2xM, average, average example 3xM, excellent, average example 4xM, average, average example 5xM, average, excellent, comparative example 1oS, excellent, excellent, comparative example 2oM, excellent, excellent, comparative example 3oM, poor, average, comparative example 4oS, poor, inadequate, comparative example 5xL, poor, inadequate

[0081] Referring to Table 2 above, in Examples 1 to 5, no pores were generated in the insulating film, and the gel time at 125°C was 2 to 4 minutes, confirming excellent flowability and leveling properties. In addition, flexibility and warpage were above average or excellent, confirming that sufficient mechanical properties could be secured. On the other hand, in Comparative Examples 1 to 5, it was shown that none of the pore generation, gel time suitability, flexibility, or warpage was satisfactory.

[0082] Specifically, in the examples, Example 1 containing 30% of a high equivalent weight solid epoxy resin of 1000 to 1500 g / eq and a liquid epoxy resin of less than 500 g / eq was shown to have excellent flexibility and warpage, and when Examples 1 and 3 or Examples 2, 4, and 5 were compared, flexibility and warpage were shown to be average or excellent as the content of the solid epoxy resin of 1000 to 1500 g / eq and the solid epoxy of 850 to 1500 g / eq were controlled, and it was shown that the higher the content of the high equivalent weight solid epoxy resin, the better the flexibility and warpage.

[0083] Also, referring to FIG. 1, it can be confirmed that no pores were generated in the membrane cross-section (a) of Example 1, but pores were generated in the membrane cross-section (b) of Comparative Example 1. In this regard, comparing Comparative Example 1 and Example 2 in Table 2, in Comparative Example 1, where a high equivalent weight epoxy resin of 1500 g / eq or more and a hardener having a softening point of 150°C or more were applied, flexibility and warpage were good due to the application of a high equivalent weight, but the gel time was short due to over-drying, indicating poor flowability and the generation of pores. However, unlike Comparative Example 1, in Comparative Example 2, where a hardener of 125°C or less was applied, the gel time was satisfactory, but it was confirmed that pores were generated due to over-drying by the high equivalent weight epoxy resin. This means that it is difficult to control flowability unless the equivalent weight of the solid epoxy resin is controlled even if a low equivalent weight liquid epoxy resin is included.

[0084] Comparing Comparative Example 3 with Example 3, it was found that pores were generated due to the use of a high softening point hardener without including a low equivalent weight liquid epoxy resin, and that curing shrinkage occurred due to the application of 850 to 1500 g / eq of medium equivalent weight epoxy, resulting in insufficient flexibility. In addition, comparing Comparative Examples 4 and 5 with Example 3, it was found that the application of a solid epoxy resin of 850 to 1500 g / eq resulted in insufficient flexibility and warping due to shrinkage. At this time, when Comparative Examples 4 and 5 were compared, it was confirmed that the gel time was longer and pores did not occur in Comparative Example 5, which mixed an inorganic filler with an average particle size of 14 μm and an inorganic filler with an average particle size of 30 μm, compared to Comparative Example 4, which only included an inorganic filler with an average particle size of 30 μm. This is because the flowability and leveling properties were controlled by the application of inorganic fillers with different particle sizes.

[0085] From the above results, it can be confirmed that the liquid insulating material of the present invention controls the equivalent weight and softening point of the epoxy resin by including a solid epoxy resin and a liquid epoxy resin, and controls the gel time and over-drying by including a hardener having a softening point of 125°C or lower, thereby exhibiting sufficient flowability without generating pores, and improves the mechanical properties while increasing the leveling property by including two or more types of inorganic fillers with different particle sizes.

[0086]

[0087] In this way, according to the present invention, it is expected that a liquid insulating material having excellent physical properties can be provided while improving flowability and leveling properties through controlling the equivalent ratio of the epoxy resin and the hardener, controlling the softening point, and controlling the particle ratio.

Claims

1. An epoxy resin comprising a solid epoxy resin having a softening point of up to 150°C and an epoxy equivalent of 850 to 1500 g / eq and a liquid epoxy resin having an epoxy equivalent of up to 500 g / eq; A hardener having a softening point of up to 125°C; and An inorganic filler comprising at least two types of inorganic particles having different average particle sizes; A liquid insulating material characterized by having flowability, leveling properties and flexibility by controlling gel time.

2. In paragraph 1, The above epoxy resin is a liquid insulating material characterized in that it contains solid epoxy resin and liquid epoxy resin in a weight ratio of 50 to 80:10 to 50.

3. In paragraph 3, A liquid insulating material, characterized in that the above solid epoxy resin or liquid epoxy resin is at least one selected from bisphenol-based epoxy resin, biphenyl-based epoxy resin, naphthalene-based epoxy resin, fluorene-based epoxy resin, novolac-based epoxy resin, phenol novolac-based epoxy resin, cresol novolac-based epoxy resin, pentadiene-based epoxy resin, dicyclopentadiene-based epoxy resin, trishydroxylphenylmethane-based epoxy resin, and tetraphenylmethane-based epoxy resin.

4. In paragraph 1, A liquid insulating material, characterized in that the inorganic filler is contained in an amount of 70 to 90% of the total weight of the insulating material.

5. In paragraph 5, A liquid insulating material characterized in that the above inorganic filler comprises inorganic particles having an average particle size of 25 to 40 ㎛ and inorganic particles having an average particle size of 5 to 20 ㎛ in a weight ratio of 60:40 to 80:

20.

6. In paragraph 1, A liquid insulating material, characterized in that the inorganic filler is at least two selected from the group consisting of natural silica, fused silica, amorphous silica, hollow silica, aluminum hydroxide, boehmite, magnesium hydroxide, molybdenum oxide, zinc molybdate, zinc borate, zinc stannate, aluminum borate, potassium titanate, magnesium sulfate, silicon carbide, zinc oxide, boron nitride (BN), silicon nitride, silicon oxide, aluminum titanate, barium titanate, barium strontium titanate, aluminum oxide, alumina, clay, kaolin, talc, calcined clay, calcined kaolin, calcined talc, mica, short glass fibers, and mixtures thereof.

7. In paragraph 1, The above liquid insulating material is characterized in that the gel time at 125 to 150°C is 90 to 240 seconds.

8. In paragraph 1, A liquid insulating material characterized in that the above insulating material is for packaging semiconductors, semiconductor substrates, or electrical and electronic components.

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