Epoxy encapsulation composition for semiconductors, its preparation method, and semiconductor device encapsulation layer

Abstract

The present application discloses an epoxy encapsulation composition for semiconductors, a preparation method thereof, and a semiconductor device encapsulation layer. The epoxy encapsulation composition comprises the following components in mass percentage: epoxy resin, 5% - 20%; curing agent, 1% - 8%; catalyst, 0.01% - 0.9%; filler, 70% - 90%; titanium dioxide, 0.5% - 2.5%; flame retardant, 5% - 15%; other additives, 1% - 8%. Each component in the epoxy encapsulation composition of the present application acts together, so that after the epoxy encapsulation composition is prepared into an encapsulation coating of a semiconductor device, it has a specific whiteness and more excellent insulation performance and ultraviolet reflectivity.

Description

Technical Field

[0001] This application belongs to the technical field of epoxy encapsulation materials, and particularly relates to an epoxy encapsulation composition for semiconductors, a method for preparing a semiconductor device encapsulation layer, and a semiconductor device encapsulation layer. Background Art

[0002] Epoxy encapsulation compositions for power electronic semiconductor devices generally include epoxy resins, curing agents, etc. In related technologies, the color of the encapsulation materials for power devices is generally black. On the one hand, using black can effectively protect the devices; on the other hand, using black can make the semiconductor devices perform stably even at relatively high temperatures, such as reflow temperatures, and using black can use carbon black as the main filler, making the cost of the encapsulation materials relatively low.

[0003] With the development of technology, the black epoxy encapsulation compositions cannot fully meet the usage requirements and need to be improved urgently. Summary of the Invention

[0004] In view of this, this application provides an epoxy encapsulation composition for semiconductors, its preparation method, and a semiconductor device encapsulation layer, aiming to provide a white epoxy encapsulation composition with a specific color number, having more excellent insulation performance and ultraviolet reflectivity.

[0005] In a first aspect, an embodiment of this application provides an epoxy encapsulation composition for semiconductors, including the following components in mass percentage:

[0006] Epoxy resin, 5% - 20%;

[0007] Curing agent, 1% - 8%;

[0008] Catalyst, 0.01% - 0.9%;

[0009] Filler, 70% - 90%;

[0010] Titanium dioxide, 0.5% - 2.5%;

[0011] Flame retardant, 5% - 15%;

[0012] Other additives, 1% - 8%.

[0013] According to an embodiment of one aspect of this application, the epoxy resin includes one or more of cresol novolac epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, and polyphenol glycidyl ether epoxy resin.

[0014] According to an embodiment of one aspect of this application, the curing agent includes any one or more of acid anhydride compounds and organic phosphine compounds.

[0015] According to an embodiment of one aspect of the present application, the acid anhydride compound includes one or more of methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride.

[0016] According to an embodiment of one aspect of the present application, the organic phosphine compound is selected from triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tris(p-methylphenyl)phosphine, tris(nonylphenyl)phosphine, or a combination thereof.

[0017] According to an embodiment of one aspect of the present application, the filler is selected from alumina fine powder, titanium oxide fine powder, silicon nitride fine powder, aluminum nitride fine powder, and silica fine powder.

[0018] According to an embodiment of one aspect of the present application, the flame retardant includes any one or more of halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, phosphorus-halogen-based flame retardants, phosphorus-nitrogen-based flame retardants, or is a hydroxide flame retardant.

[0019] According to an embodiment of one aspect of the present application, the catalyst includes one or more of imidazole compounds and tertiary amine compounds.

[0020] According to an embodiment of one aspect of the present application, the imidazole compound is selected from 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-(heptadecyl)imidazole, or a combination thereof;

[0021] According to an embodiment of one aspect of the present application, the tertiary amine compound is selected from triethylamine benzyldimethylamine, α-methylbenzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)undec-7-ene, or a combination thereof.

[0022] According to an embodiment of one aspect of the present application, the other additives include one or more of coupling agents, toughening agents, and mold release agents.

[0023] In a second aspect, an embodiment of the present application provides a method for preparing a semiconductor device encapsulation layer, including:

[0024] Providing each component and its content in the epoxy encapsulation composition, wherein the epoxy encapsulation composition includes the following components in mass percentage: epoxy resin, 5%-20%; curing agent, 1%-8%; catalyst, 0.01%-0.9%; filler, 70%-90%; titanium dioxide, 0.5%-2.5%; flame retardant, 5%-15%; other additives, 1%-8%;

[0025] Mixing each component and performing melt-kneading to obtain a melt;

[0026] Cooling and pulverizing the melt to obtain the semiconductor device encapsulation layer.

[0027] According to an embodiment of one aspect of the present application, under heating conditions, each component is mixed and melt-kneaded to obtain a melt.

[0028] In a third aspect, an embodiment of the present application provides a semiconductor device encapsulation layer, which is prepared by the method of the second aspect.

[0029] According to an embodiment of one aspect of the present application, according to the blue light whiteness method, the whiteness of the semiconductor device encapsulation layer is 70 - 99.5.

[0030] According to an embodiment of one aspect of the present application, according to the blue light whiteness method, the whiteness of the semiconductor device encapsulation layer is 75 - 95.

[0031] Compared with the prior art, the present application has at least the following beneficial effects:

[0032] The epoxy encapsulation composition provided by the present application includes 5% - 20% epoxy resin; 1% - 8% curing agent; 0.01% - 0.9% catalyst; 70% - 90% filler; 0.5% - 2.5% titanium dioxide; 5% - 15% flame retardant; 1% - 8% other additives. Through the combined action of the above components, especially the combined action of 0.5% - 2.5% titanium dioxide and other components, after the epoxy encapsulation composition is prepared into the encapsulation coating of a semiconductor device, it has a specific whiteness, and has more excellent insulation performance and ultraviolet reflectivity. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the drawings without creative efforts.

[0034] Figure 1 It is a schematic flowchart of the preparation method of the semiconductor device encapsulation layer of an embodiment of the present application. Detailed Embodiments

[0035] In order to make the application purpose, technical solutions and beneficial technical effects of the present application clearer, the following further details the present application in combination with embodiments. It should be understood that the embodiments described in this specification are only for explaining the present application and not for limiting the present application.

[0036] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form a range not explicitly recited; and any lower limit can be combined with other lower limits to form a range not explicitly recited, and similarly any upper limit can be combined with any other upper limit to form a range not explicitly recited. In addition, although not explicitly recited, each point or single value between the range endpoints is included within the range. Thus, each point or single value can be used as its own lower or upper limit and combined with any other point or single value or combined with other lower or upper limits to form a range not explicitly recited.

[0037] In the description of this application, it should be noted that unless otherwise specified, "above" and "below" include this number, and the meaning of "multiple" in "one or more" is two or more than two.

[0038] The above application content of this application does not intend to describe every disclosed embodiment or every implementation mode in this application. The following description more specifically exemplifies exemplary embodiments. Throughout the application, guidance is provided through a series of examples, which can be used in various combinations. In each instance, the enumeration is only a representative group and should not be construed as exhaustive.

[0039] Epoxy encapsulation composition for semiconductor

[0040] In a first aspect, this application provides an epoxy encapsulation composition for semiconductor, comprising the following components in mass percentage:

[0041] Epoxy resin, 5% - 20%;

[0042] Curing agent, 1% - 8%;

[0043] Catalyst, 0.01% - 0.9%;

[0044] Filler, 70% - 88%;

[0045] Titanium dioxide, 0.5% - 2.5%;

[0046] Flame retardant, 5% - 15%;

[0047] Other additives, 1% - 8%.

[0048] In the related art, devices with electromagnetic compatibility are mainly packaged in black. On the one hand, carbon black is commonly used as a color developer in excellent epoxy molding compounds. On the other hand, using black for the power device can protect the internal devices from being damaged by external irradiation, such as ultraviolet rays. And using carbon black can improve the stability of the packaging material, and it is still very stable even under a relatively high reflow stability, and carbon black is cheap and easily available.

[0049] Titanium dioxide is an inorganic compound with the chemical formula TiO2. It is a white solid or powdery amphoteric oxide with a molecular weight of 79.866. It is non-toxic, opaque, has a certain whiteness and brightness, strong adhesion, and is not prone to chemical changes. It has good thermal stability, the lowest density and the largest surface area compared with other common white powders.

[0050] It has been found through research that by mixing 0.5%-2.5% titanium dioxide with specific mass fractions of epoxy resin, curing agent, catalyst, filler, etc., and extruding, the prepared epoxy coating has more excellent ultraviolet reflectivity and insulation.

[0051] According to the embodiments of the present application, the viscosity of the epoxy encapsulation composition at a temperature of 175 °C can be 1-100 Pa·s, preferably 5-30 Pa·s. The epoxy encapsulation composition also has a relatively low water absorption rate, low dielectric constant, low dielectric loss, and excellent heat resistance. The epoxy encapsulation composition has the necessary formability and flame retardancy.

[0052] In some embodiments, the epoxy resin is selected from o-cresol novolac epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, polyphenol glycidyl ether epoxy resin. The above epoxy resins can act with components such as titanium dioxide, which helps to improve the whiteness, insulation and ultraviolet reflectivity of the cured epoxy encapsulation composition.

[0053] In some embodiments, the epoxy resin can also be selected from aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, biphenyl type epoxy resin, dicyclopentadiene type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin or a combination thereof.

[0054] In some embodiments, the average particle size Dv50 of titanium dioxide is 5-25 μm, and can be optionally 10-22 μm. Titanium dioxide within the above particle size range can be better mixed with the components of the epoxy encapsulation composition and dispersed in an organic phase such as epoxy resin, making it have good and more uniform whiteness and ultraviolet reflectivity.

[0055] The volume average particle size Dv50 has the meaning well known in the art, which represents the particle size corresponding to when the cumulative volume distribution percentage of the material reaches 50%, and can be measured by instruments and methods well known in the art. For example, it can be conveniently measured with a laser particle size analyzer by referring to GB / T19077-2016 Laser diffraction method for particle size distribution, such as the Mastersizer 2000E type laser particle size analyzer of Malvern Instruments Limited in the UK. The volume average particle size Dv50 can be measured for its raw materials or separated epoxy encapsulation composition.

[0056] In some embodiments, the curing agent includes several types of carboxylic acid compounds and organic phosphine compounds.

[0057] In some embodiments, the organophosphorus compound is selected from triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tris(p-methylphenyl)phosphine, tris(nonylphenyl)phosphine, or a combination thereof.

[0058] In some embodiments, the filler is selected from alumina fine powder, titanium oxide fine powder, silicon nitride fine powder, aluminum nitride fine powder, and silica fine powder.

[0059] In some embodiments, the flame retardant is any one or more of a halogen-based flame retardant, a phosphorus-based flame retardant, a nitrogen-based flame retardant, a phosphorus-halogen-based flame retardant, a phosphorus-nitrogen-based flame retardant, or a hydroxide flame retardant.

[0060] In some embodiments, the catalyst is selected from imidazole compounds, imidazole compounds, or a combination thereof.

[0061] In some embodiments, the imidazole compound is selected from 2-methylimidazole, 2,4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-(heptadecyl)imidazole, or a combination thereof.

[0062] In some embodiments, the tertiary amine compound is selected from triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)undec-7-ene, or a combination thereof.

[0063] In some embodiments, other additives are selected from coupling agents, toughening agents, release agents, or a combination thereof. In some embodiments, the coupling agent is selected from any one or more of γ-glycidoxypropyl ether trimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-aminopropyltrimethoxysilane. In some embodiments, the toughening agent includes one or more of ABS resin and MBS resin. In some embodiments, the release agent is selected from any one or more of carnauba wax, polyethylene wax, oxidized polyethylene wax, Fischer-Tropsch wax, polypropylene wax, and fatty acid wax. According to the embodiments of the present application, the epoxy encapsulation composition contains 0.3%-3% of a coupling agent, 0.3%-5% of a toughening agent, and 0.2%-4% to enable the epoxy encapsulation composition to have corresponding properties.

[0064] According to the embodiments of the present application, the epoxy encapsulation composition can be applied to low-power devices adjacent to high-power devices in the environment, such as devices with a small pulse width, surface mount devices (SMDs) with low heat generation, or heat dissipation mainly from the bottom radiator. For example, products with a low thermal resistance coefficient (Rthjc), more specifically, discrete packages (DPAK), D2PAK, DFN, etc.

[0065] Method for preparing a semiconductor device encapsulation layer

[0066] In a second aspect, the present application provides a method for preparing a semiconductor device encapsulation layer, as Figure 1 shown, including:

[0067] S100. Provide the components and contents in the epoxy encapsulation composition. Among them, the epoxy encapsulation composition includes the following components by mass percentage: epoxy resin, 5%-20%; curing agent, 1%-8%; catalyst, 0.01%-0.9%; filler, 70%-90%; titanium dioxide, 0.5%-2.5%; flame retardant, 5%-15%; other additives, 1%-8%;

[0068] S200. Mix the components and perform melt compounding to obtain a melt;

[0069] S300. Cool and crush the melt to prepare a semiconductor device encapsulation layer.

[0070] In some embodiments, under heating conditions, preform the cooled and crushed melt to obtain a formed material of the epoxy encapsulation composition. For example, preforming can make it into a cake.

[0071] In some embodiments, under heating conditions, mix the components and perform melt compounding to obtain a melt. In some embodiments, the heating temperature can be 60-110°C, and can also be 100-120°C, 80-100°C, 90-120°C, 70-110°C, 80-120°C, etc.

[0072] Semiconductor device encapsulation layer

[0073] In a third aspect, the present application provides a semiconductor device encapsulation layer prepared by the method of the second aspect.

[0074] In some embodiments, according to the blue light whiteness method, the whiteness of the semiconductor device encapsulation layer is 70-99.5, and can be optionally 75-95. The semiconductor device encapsulation layer prepared by the above method has good whiteness, insulation and ultraviolet reflectivity. When in use, it is marked for easy recognition.

[0075] Embodiment

[0076] The following examples describe more specifically the content disclosed in the present application. These examples are for illustrative purposes only, as various modifications and variations within the scope of the present application disclosure are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized by conventional methods and can be used directly without further treatment, and the instruments used in the examples are all commercially available.

[0077] The raw material components and sources used in the examples of the present application are as follows:

[0078] o-Cresol novolac epoxy resin (from CYDCN-200H manufactured by Baling Petrochemical)

[0079] Biphenyl type epoxy resin (from YX-4000 manufactured by Japan Epoxy Resins Co., Ltd.)

[0080] Silica micropowder (dv50 is 22 μm)

[0081] Coupling agent KH560 (from KH560 model of Sinopharm Group)

[0082] Flame retardant: Zinc borate (dv50 is 1 μm), Clariant Exolit OP 935.

[0083] Examples 1-5

[0084] Examples 1-5 of the present application provide an epoxy encapsulation composition for semiconductors, which includes the following components in mass percentage:

[0085] Epoxy resin, 5%-20%;

[0086] Curing agent, 1%-8%;

[0087] Catalyst, 0.01%-0.9%;

[0088] Filler, 70%-88%;

[0089] Titanium dioxide, 0.5%-2.5%;

[0090] Flame retardant, 5%-10%;

[0091] Other additives, 1%-8%.

[0092] The present application provides a method for preparing an encapsulation layer of a semiconductor device, including:

[0093] S100. Provide the components of the above epoxy encapsulation composition;

[0094] S200. At a temperature of 60 - 130 °C, mix the components and perform melt compounding to obtain a melt;

[0095] S300. Cool and pulverize the melt to produce a semiconductor device encapsulation layer, and after pulverization, press it into a cake shape with mechanical pressure. The specific components and processes of Examples 1 - 5 are shown in Table 1

[0096] Table 1

[0097]

[0098]

[0099] Comparative Example 1

[0100] The difference between this Comparative Example 1 and Example 1 lies in the raw material composition, where ZnO is used to replace titanium dioxide.

[0101] Comparative Example 2

[0102] The difference between this Comparative Example 2 and Example 1 lies in the raw material composition, where the content of titanium dioxide is 3.5%, and the corresponding part of the increased titanium dioxide content reduces the content of the filler.

[0103] Comparative Example 3

[0104] The difference between this Comparative Example 3 and Example 1 lies in the raw material composition, where the content of titanium dioxide is 0.12%, and the reduced part is supplemented with the filler.

[0105] Comparative Example 4

[0106] The difference between this Comparative Example 4 and Example 1 lies in the raw material composition, where MgO is used to replace epoxy resin.

[0107] Comparative Example 5

[0108] Use a commercially available encapsulation material with raw materials including carbon black and E500HA resin, model E500HA from Sumitomo Corporation.

[0109] Test section

[0110] 1) Color comparison: Use a whiteness meter and the blue light whiteness method to detect the encapsulation coatings of Examples 1 - 5 and Comparative Examples 1 - 5. The test results are shown in Table 3.

[0111] 2) Volume resistivity detection: Use an insulation resistance test instrument from Agilent to detect the encapsulation coatings of Examples 1 - 5 and Comparative Examples 1 - 5. The test results are shown in Table 3.

[0112] 3) Ultraviolet reflectance detection: Using a UV / Visible spectrometer from PE Company in the United States, the encapsulation coatings of Examples 1-5 and Comparative Examples 1-5 were detected, and the detection results are shown in Table 3.

[0113] 4) Ultraviolet transmittance detection: Using a UV / Visible spectrometer from PE Company in the United States, the encapsulation coatings of Examples 1-5 and Comparative Examples 1-5 were detected, and the detection results are shown in Table 3.

[0114] 5) Bonding performance detection: Using the lap shear test method and a universal mechanical testing machine, the bonding properties of the epoxy encapsulation compositions of Examples 1-5 and Comparative Examples 1-5 were detected, and the detection results are shown in Table 3.

[0115] 6) Printing / Marking detection: Using ink to print two-dimensional codes on the obtained encapsulation coatings, and they should be scanned. Those that can be effectively recognized are judged as clear, and those that cannot be effectively recognized are judged as unclear.

[0116] Table 2

[0117]

[0118] According to the results in Table 3, the whiteness of the coatings prepared in the examples is 80-91. Compared with the comparative examples, white is more easily recognizable. When two-dimensional codes and relevant markings are attached to the white encapsulation layer, it is more convenient and clearer to recognize. After testing, the encapsulation coatings prepared in the examples have better insulation, ultraviolet resistance, and bonding properties compared with the comparative examples.

[0119] For the epoxy encapsulation composition and encapsulation coating prepared in Comparative Example 1, compared with Examples 1-5, the bonding property of the epoxy encapsulation composition meets the requirements, but the insulation and ultraviolet resistance of the encapsulation coating meet the requirements, but the whiteness and printing effect of the encapsulation coating are poor. The reason is that ZnO is used to replace titanium dioxide.

[0120] For the epoxy encapsulation composition and encapsulation coating prepared in Comparative Example 2, compared with Examples 1-5, the bonding property of the epoxy encapsulation composition does not meet the requirements, and other relevant properties meet the standards. The reason may be that too much titanium dioxide is used.

[0121] For the epoxy encapsulation compositions and encapsulation coatings prepared in Comparative Examples 3-5, compared with Examples 1-5, the whiteness is low and does not meet the requirements, and there are also unqualified phenomena in the ultraviolet reflectance. The reason may be that the components of the epoxy encapsulation composition have changed.

[0122] As described above, it is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An epoxy encapsulation composition for semiconductors, comprising the following components in mass percentages: o-cresol novolac epoxy resin, 5% - 20%; 4,4-diaminodiphenyl sulfone, 1% - 8%; 2-methylimidazole, 0.5% - 0.9%; Filler, 70% - 90%, the filler is selected from any one or a combination of several of alumina micropowder, silicon nitride micropowder, aluminum nitride micropowder, and silica micropowder; Titanium dioxide, 0.5% - 1.5%; Flame retardant, 5% - 15%; Other additives, 1% - 8%; the sum of the mass percentages of the amounts of the above components is 100%.

2. The epoxy encapsulation composition according to claim 1, wherein, the flame retardant includes any one or a combination of several of halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, phosphorus-halogen-based flame retardants, phosphorus-nitrogen-based flame retardants, or is a hydroxide flame retardant.

3. The epoxy encapsulation composition according to claim 1, wherein, the other additives include one or a combination of several of coupling agents, toughening agents, and mold release agents.

4. A method for preparing a semiconductor device encapsulation layer, wherein, it includes: Providing each component and its content in the epoxy encapsulation composition, wherein the epoxy encapsulation composition comprises the following components in mass percentages: o-cresol novolac epoxy resin, 5% - 20%; 4,4-diaminodiphenyl sulfone, 1% - 8%; 2-methylimidazole, 0.01% - 0.9%; filler, 70% - 90%; titanium dioxide, 0.5% - 1.5%; flame retardant, 5% - 15%; other additives, 1% - 8%, the filler is selected from any one or a combination of several of alumina micropowder, silicon nitride micropowder, aluminum nitride micropowder, and silica micropowder; the sum of the mass percentages of the amounts of the above components is 100%; Mixing each component and performing melt kneading to obtain a melt; Cooling and pulverizing the melt to prepare the semiconductor device encapsulation layer.

5. The method according to claim 4, wherein, under heating conditions, mixing each component and performing melt kneading to obtain a melt.

6. A semiconductor device encapsulation layer, wherein, it is prepared by the method according to claim 4 or 5; according to the blue light whiteness method, the whiteness of the semiconductor device encapsulation layer is 70 - 99.

5.

7. The semiconductor device encapsulation layer according to claim 6, wherein, the whiteness of the semiconductor device encapsulation layer is 78 - 95.

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