Direct writing double-cured gasket

Abstract

A composition for producing a filler, comprising a plurality of ceramic particles, a liquid oxirane monomer, an ultraviolet initiator that absorbs ultraviolet rays, and a thermal initiator.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims priority to U.S. Provisional Patent Application No. 63 / 356,731, filed on June 29, 2022, which is hereby incorporated by reference in its entirety.

Background Art

[0002] This disclosure relates to photo - and thermosetting composite materials, and more specifically to photo - and thermosetting composite materials for direct - write semiconductor applications.

[0003] In a conventional printed circuit board, electronic components or chips are mounted on the surface of the bottom - most wiring layer. An insulating layer and the top - most wiring layer are laminated on the chip, and via - holes are formed for electrical connection between the wiring layer and the chip.

[0004] In response to the requirements for higher functionality and miniaturization of electronic devices, recent technological trends are towards higher density and miniaturization of electronic components. For this reason, there is an increasing demand for miniaturization of printed circuit boards that can mount electronic components at high density. Therefore, the development of multilayer circuit boards that electrically connect wiring formed between wiring layers or on different layers and electrical components via via - holes is in progress. Multilayer circuit boards reduce the wiring for connecting electronic components to each other, increase the surface area of the printed circuit board by wiring at high density, and provide excellent electrical characteristics.

Summary of the Invention

[0005] According to some embodiments, a composition for producing a filler, comprising a plurality of ceramic particles, a liquid oxirane monomer, an ultraviolet initiator that absorbs ultraviolet light, and a thermal initiator.

[0006] According to other embodiments, the chip-embedded printed circuit board includes a cavity in the printed circuit board, a chip in the cavity of the printed circuit board, and a gap filler in the gap of the cavity for sealing the chip in the printed circuit board. The gap filler comprises an oxirane-based polymer and ceramic particles, and its coefficient of thermal expansion is about 10 to about 150 parts per million degrees Celsius.

[0007] However, according to another embodiment, a method for screening initiator combinations for curing a polymer includes providing a first composition comprising a liquid oxirane monomer and a UV initiator. The method further includes exposing the first composition to ultraviolet light at a wavelength absorbed by the UV initiator to initiate polymerization of the first polymer and measuring the enthalpy emitted by the first polymer. The method also includes providing a second composition comprising a liquid oxirane monomer, a UV initiator, and a thermal initiator, and exposing the second composition to ultraviolet light at a wavelength absorbed by the UV initiator to initiate polymerization of the second polymer. The method includes measuring the enthalpy emitted by the second polymer formed by the second composition and comparing the enthalpy of the first polymer with the enthalpy of the second polymer. Based on the comparison, the method includes determining whether the UV initiator and the thermal initiator inhibit each other.

[0008] Further features and advantages are realized through the technology of this disclosure. Other embodiments and aspects of this disclosure are described in detail herein and are considered to be part of the claimed disclosure. Refer to the description and drawings for a better understanding of this disclosure, including its advantages and features.

[0009] For a more complete understanding of this disclosure, please refer to the following brief description in conjunction with the accompanying drawings and detailed description. Similar reference numerals represent similar parts. [Brief explanation of the drawing]

[0010] [Figure 1A]This is a top view of a chip-embedded printed circuit board.

[0011] [Figure 1B] This is a side cross-sectional view of Figure 1A.

[0012] [Figure 2] This is a side cross-sectional view of a method for embedding a chip into a printed circuit board using a gap filler.

[0013] [Figure 3A] This is the differential scanning calorimetry (DSC) spectrum of a gap filler after UV photocuring using a combination of ultraviolet (UV) initiator #1 and a different thermal initiator.

[0014] [Figure 3B] This is the differential scanning calorimetry (DSC) spectrum of a gap filler after UV photocuring using a combination of UV initiator #2 and a different thermal initiator.

[0015] [Figure 3C] This is the differential scanning calorimetry (DSC) spectrum of a gap filler after thermal curing using a combination of thermal initiator #3 and a different UV initiator.

[0016] [Figure 3D] This is the differential scanning calorimetry (DSC) spectrum of a gap filler after thermal curing using a combination of thermal initiator #4 and a different UV initiator.

[0017] [Figure 4] The differential scanning calorimetry (DSC) spectra of gap fillers containing various monomers are shown.

[0018] [Figure 5-1] The Fourier transform infrared (FTIR) spectra of gap fillers containing various monomers are shown. [Figure 5-2]Shows the Fourier transform infrared (FTIR) spectrum of a gap filler containing various monomers (continuation of Fig. 5-1).

[0019] [Figure 6] Shows the coefficient of thermal expansion (CTE) of a gap filler containing various amounts of boron nitride and glass sphere particles.

Embodiments for Carrying Out the Invention

[0020] As described above, a conventional printed circuit board has laminated chips mounted on its surface together with metal-filled vias that connect the upper and lower wiring layers. However, creating such via holes involves complex processing steps.

[0021] Using chips embedded in a printed circuit board eliminates the need for via wiring, reducing processing costs and complexity. A cavity is formed in the printed circuit board, a chip is placed in the cavity, and a material is used to fill the gap between the chip and the printed circuit board.

[0022] Norland Electronic Adhesive 121 (NEA 121) is a mercapto-ester / benzophenone composition and is an adhesive for temporary bonding, filling, sealing, insulating protective coating, and tamper-proofing of precision products. However, a drawback of NEA 121 as a gap filler for embedding chips in printed circuit boards is that its viscosity is too low (approximately 300 centipoise), resulting in minimal shear reduction, which is undesirable because the low viscosity and minimal shear reduction cause capillary wetting of the sidewalls of the joint and material loss due to gaps at the bottom of the device construction. Furthermore, CTE of NEA 121 can cause delamination and cracking of interconnects. Creative Materials 119-48 (CM 119-48) is a screen-printable, flexible, UV-curable dielectric coating that has also been used as a gasket in similar applications. However, this material has an unfavorably high viscosity (approximately 150,000 centipoise), which causes the material to maintain its shape during extrusion, resulting in a rough finish and making it difficult to print silver on it.

[0023] Accordingly, this specification describes a gap filler composition and a method for embedding a chip in a printed circuit board that eliminates via wiring, thereby reducing processing costs and device complexity. The composition is printable for direct writing applications and has thermal expansion properties similar to printed conductive inks used to form interconnects, which is a crucial step in creating a more robust printed structure. The composition and materials enable the printing of multilayer printed microwave elements, particularly in embodiments where a gap from the chip to the printed circuit board is filled, by improving the robustness of the printed interconnects.

[0024] The gap filler composition comprises a liquid oxirane monomer, a UV initiator, and a thermal initiator, which are cured by a dual curing mechanism involving both UV light and heat. The dual curing mechanism allows for initial curing of the material with ultraviolet light to fix it to the substrate, followed by post-treatment with heat, thereby increasing the degree of curing and material strength, and lowering the CTE. Since a lower CTE is desirable and to prevent delamination of printed interconnects, the composition further includes a heat-resistant organic matrix that locks into inorganic particles and provides a desirable shear-thickening effect. Because the composition does not require a syringe, it can be used in conventional direct writing manufacturing equipment. The dual curing composition enables a post-treatment step that simultaneously promotes monomer conversion and provides the lowest possible CTE. To use the composition as a gap filler, a cavity is formed in the printed circuit board, a chip is placed in the cavity, and a dual-curing (thermal and UV) composite ink for direct writing is placed to fill the gap in the cavity between the chip and the circuit board, providing an embedded die sealed with a printable gasket material. An interposer is placed on the cavity to provide electrical connections to the chip.

[0025] The gap fillers described herein are first formed by providing a composition comprising a liquid oxirane monomer, an ultraviolet-absorbing ultraviolet initiator, a thermal initiator, and a plurality of ceramic particles. Since the monomer is liquid and solvents cause undesirable shrinkage, no additional solvent is required. In one or more embodiments, the composition is solvent-free (or does not contain) or contains less than 1% by weight of solvent, less than 5% by weight of solvent, or less than 10% by weight of solvent.

[0026] The monomer is an oxirane monomer, which polymerizes via a less strained ring-opening mechanism compared to linear monomers such as acrylates. Oxirane monomers polymerize via a cationic pathway, are not inhibited by oxygen, and exhibit improved stability in contrast to acrylates. In some embodiments, the composition is (or does not contain) an acrylate monomer. In some embodiments, the composition contains less than 1% by weight of an acrylate monomer, less than 5% by weight of an acrylate monomer, or less than 10% by weight of an acrylate monomer.

[0027] In some embodiments, the monomers used in the composition have boiling points above 130°C, so they do not boil before causing the monomer to undergo thermal curing, which occurs at approximately 110°C. In other embodiments, the monomers have boiling points above 150°C. However, in some embodiments, the monomers have boiling points between approximately 130°C and approximately 300°C.

[0028] The monomers used in the composition have even lower viscosity, for example, less than 17 centipoise in some embodiments, so that a large amount of ceramic particles can be combined in the composition to lower the CTE. In other embodiments, the monomers have a viscosity of less than 10 centipoise, less than 5 centipoise, or less than 2 centipoise. However, in embodiments, the monomers have a viscosity of about 1 to about 5,000 centipoise.

[0029] The monomers used in the composition are oxirane monomers, which are monomers containing one or more oxirane structures. In some embodiments, the oxirane monomer contains two oxirane structures. In other embodiments, the oxirane monomer contains three oxirane structures. In some embodiments, the oxirane structure monomer is a symmetric compound. In other embodiments, the oxirane monomer contains one or more oxirane structures and one or more ethers. In one or more embodiments, the oxirane monomer contains two oxirane structures and two ether structures. However, in some embodiments, the oxirane monomer contains three oxirane structures and three ether structures. Furthermore, in other embodiments, the oxirane monomer does not contain aromatic structures.

[0030] Non-limiting examples of oxirane monomers include butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, resorcinol diglycidyl ether, bisphenol-A diglycidyl ether resins, novolac epoxy resins, or any combination thereof.

[0031] A non-limiting example of an oxirane monomer has the following structure. [ka]

[0032] Another non-limiting example of an oxirane monomer has the following structure: [ka]

[0033] The UV initiator in the composition absorbs ultraviolet light with a wavelength of about 200 nanometers to about 400 nanometers. In one or more embodiments, the UV initiator absorbs ultraviolet light with a wavelength of about 260 nanometers to about 360 nanometers. In some embodiments, the UV initiator is a hexafluorophosphate. In one or more embodiments, the UV initiator is a hexafluorophosphate having the following structure. [ka]

[0034] The composition further comprises a thermal initiator. The thermal initiator has a thermal activation temperature above 110°C, acts as a Lewis acid to initiate cationic polymerization, and can post-treat the heat-treated material to further enhance the degree of curing. In one or more embodiments, the thermal activation temperature is above 120°C or above 130°C. In one or more embodiments, the thermal initiator is a Lewis acid. A non-limiting example of a thermal initiator has the following structure. [ka]

[0035] Due to a dual curing mechanism, the filler is cured first by ultraviolet light and then by heat. Upon absorption of ultraviolet light, the energy of the UV initiator generates free radicals that react with the monomer, initiating polymerization and UV curing. The UV initiator can cure the gap filler by using ultraviolet light from an ultraviolet source such as a mercury lamp or an LED lamp. Subsequently, upon absorption of heat, the catalyst is converted to HBF4, a strong Lewis acid. Protons from the Lewis acid can then be added to the oxygen atoms of the oxirane monomer. This then leads to cationic polymerization between the oxonium ion and all available oxirane monomers. The composition further includes an inert inorganic filler, which is a plurality of ceramic particles. In some embodiments, the ceramic particles are high aspect ratio particles, such as boron nitride. Due to the high aspect ratio of the particles in a low-viscosity liquid, when shear is applied, they align in the direction of flow, resulting in a shear viscosity reduction effect. This shear viscosity reduction results in smooth, high-resolution printing. Ceramic particles are thermally conductive, opaque, and do not absorb ultraviolet light, thus not hindering curing by ultraviolet light.

[0036] According to one or more embodiments, the ceramic particles are hexagonal boron nitride particles. In some embodiments, the ceramic particles have an aspect ratio of about 2:1 to about 30:1. In other embodiments, the ceramic particles have an aspect ratio of about 10:1 to about 20:1. According to one or more embodiments, the ceramic particles have an average diameter of about 0.5 to about 1.2 micrometers. In other embodiments, the ceramic particles have an average diameter of about 0.8 to about 1.0 micrometers.

[0037] In other embodiments, the ceramic particles do not have a high aspect ratio and are spherical in shape, such as glass spheres. In one embodiment, the glass spheres have a diameter of about 0.5 to about 20 micrometers. In another embodiment, the glass spheres have a diameter of about 2 to about 10 micrometers.

[0038] In one or more embodiments, the ceramic particles are present in the gap filler composition in an amount of about 10 to about 80% by weight. In other embodiments, the ceramic particles are present in the gap filler composition in an amount of about 15 to about 60% by weight.

[0039] When polymerized by ultraviolet light and heat, the resulting double-cured gap filler contains a polymer matrix. In some embodiments, the polymer of the polymer matrix is ​​an oxirane polymer. However, in other embodiments, the polymer matrix is ​​a polymer formed from butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, resorcinol diglycidyl ether, bisphenol-A diglycidyl ether-based resins, novolac epoxy resins, or any combination thereof.

[0040] The use of ceramic particles can reduce the CTE of the composite material. In one or more embodiments, the CTE of the cured composition is about 10 to about 150 parts per million degrees Celsius. In other embodiments, the CTE of the cured composition is about 40 to about 100 parts per million degrees Celsius.

[0041] In this embodiment, a chip-embedded printed circuit board is formed using the composition. Figure 1A is a top view of the chip-embedded printed circuit board 100. Figure 1B is a side cross-sectional view of Figure 1A. The chip-embedded printed circuit board 100 includes a substrate 102 which is a printed circuit board. The substrate 102, which is a printed circuit board, has a laminated structure of conductive layers (such as copper) and insulating layers. The printed circuit board can be single-sided (e.g., one copper layer), double-sided (two copper layers on both sides of one substrate layer), or multilayer (outer and inner layers of copper alternating with insulating layers).

[0042] A cavity 110 is formed in the substrate 102 to embed the chip 104 into the substrate 102. The cavity 110 is formed by a processing method depending on the material forming the substrate 102. The cavity 110 is formed, for example, by etching, pressing, drilling, laser processing, or a combination thereof. The formed cavity 110 has dimensions of length 112 and width 114 (Figure 1A) that are larger than the chip 104 to be embedded. In some embodiments, the height 116 (or thickness, Figure 1B) of the cavity 110 is substantially the same as the height (or thickness) of the chip 104 so that the surface of the embedded chip 104 is substantially coplanar with the surface of the substrate 102. Furthermore, in other embodiments, the height 116 (or thickness) of the cavity 110 is smaller than the height (or thickness) of the chip 104, and the gap filler 106 is positioned or stacked to function as an increment up to the chip 104. After a cavity 110 is formed on the substrate 102, a chip 104 is inserted into the cavity 110. The chip 104 is also called a die or electronic component. The chip 104 is a resistor or a capacitor.

[0043] The chip-embedded circuit board 100 includes a gap filler 106 in the gap of the cavity 110 to form a gasket that seals the chip 104 in the substrate 102. The filler 106 is a thixotropic material. The chip-embedded printed circuit board 100 further includes a plurality of interposers 108 printed on the gap filler 106 to provide an electrical connection between the chip 104 and the substrate 102. The interposers 108 include, for example, silver.

[0044] Figure 2 is a side cross-sectional view showing a method for embedding a chip 204 in a printed circuit board 202. The method includes forming a cavity 210 in the printed circuit board 202 and placing the chip 204 within the cavity in the printed circuit board 202. The method further includes placing a gap filler 206 in the gap of the cavity 210 to seal the chip 204 within the cavity of the printed circuit board 202. The method further includes forming an interposer 208 on the gap filler 206 to provide an electrical connection between the chip 204 and the printed circuit board 202.

[0045] In some embodiments, the gap filler 206 is injected into the gap around the tip 204 by a syringe 220. Any method can be used to place the gap filler 206 into the cavity 210. The gap filler is irradiated with ultraviolet light to cure the composition. Then, heat is applied to further cure the composition. According to one or more embodiments, ultraviolet light is irradiated for a time such as about 2 to about 4 minutes, and then heat is irradiated for a time such as about 90 to about 150 minutes. The time for each curing step varies depending on many factors, such as the monomers used, the combination of initiators, and the specific application.

[0046] The thixotropic properties of gap filler 206 mean that shear reduction in viscosity is time-dependent. Gap filler 206 is thick or viscous under static conditions or low shear, but its viscosity decreases and it becomes flowable when shear stress is applied. In some embodiments, 5s -1 The viscosity of gap filler 206 at the shear rate is 50s -1 The viscosity of the gap filler 206 at the shear rate is greater than that of the gap filler 206 at 5s. According to one or more embodiments, the gap filler 206 is greater than that of the gap filler 206 at 5s -1 It has a viscosity of approximately 10,000 to 50,000 cps at a shear rate of 50s -1 It has a viscosity of about 1,000 to about 10,000 cps at a shear rate. According to other embodiments, the gap filler 206 is 5s -1It has a viscosity of approximately 15,000 to 30,000 cps at a shear rate of 50s -1 It has a viscosity of approximately 2,500 to 7,500 cps at a shear rate.

[0047] The dynamic viscosity of filler 206 allows it to flow into the gap between the chip and the printed circuit board under simultaneous shear stress, providing a smooth surface, making it an ideal electronic gap filler for embedding chips in printed circuit boards. The inclusion of ceramic particles (e.g., boron nitride) imparts a strong thixotropic effect to the filler. Due to the thixotropic shear-thinning effect, the viscosity of the filler decreases when shear is applied to extrude it from a syringe, and then returns to high viscosity when the shear is removed, leaving a high-resolution, smooth pattern. In contrast, the surfaces of commercially available electronic fillers are undesirable because they are either too viscous and have a rough finish that cannot be printed on, or too viscous and have a low viscosity, resulting in minimal shear-thinning, which can lead to capillary wetting of the sidewalls of the junction and loss in the gap at the bottom of the device. In addition to the gap-filling applications described above, the dynamic viscosity of the filler described herein is also suitable for other electronic applications, including any gap-filling electronic applications, or other electronic applications where dielectric material is required to provide a sloped or raised surface.

[0048] This specification also describes a method for screening initiator combinations for curing polymers. Because thermal initiators and UV initiators can interact and reduce each other's reactivity, assays have been developed to evaluate the reactivity of various combinations of UV initiators and thermal initiators. The photoDSC assay measures the reactivity of UV initiators in the presence of various thermal initiators. After incubation at a target temperature for a set time (e.g., 1 minute at 40°C), the uncured gap filler material is exposed to ultraviolet light for a set time (e.g., 3 minutes). Enthalpy (watts / gram) is measured as a function of time (minutes).

[0049] First, measure the control-photo DSC spectrum containing monomers with a single initiator (e.g., only a UV initiator, or only a thermal initiator). The measured enthalpy indicates bond formation between monomers, i.e., polymerization, induced by the single initiator. Determine the reaction enthalpy by measuring the area under the curve.

[0050] Next, the photo-DSC spectra of monomers combined with two initiators, such as a UV initiator and a thermal initiator, are measured. The resulting enthalpy again indicates the bond formation between monomers, i.e., polymerization, induced by the initiator combination. The reaction enthalpy is determined by measuring the area under the curve.

[0051] The reaction enthalpy measured with a single initiator is compared to the reaction enthalpy measured with a combination of initiators. Next, it is determined whether the reaction enthalpies are similar or dissimilar. If they are similar, inhibitory interactions between initiators on monomer conversion are minimized, resulting in a favorable outcome. However, if the reaction enthalpies are dissimilar and the sample with the combined inhibitors has a lower reaction enthalpy than the control, inhibitory interactions between initiators exist, which is undesirable.

[0052] According to one or more embodiments, a method for screening initiator combinations comprises providing a first composition comprising a liquid oxirane monomer and a single initiator, the single initiator being an ultraviolet initiator. The method comprises exposing the first composition to ultraviolet light at a wavelength absorbed by the ultraviolet initiator to initiate polymerization of the first polymer. The method further comprises measuring the enthalpy emitted by the polymer formed by the first composition. The method further comprises providing a second composition comprising a liquid oxirane monomer, an ultraviolet initiator, and a thermal initiator. The method comprises exposing the second composition to ultraviolet light at a wavelength absorbed by the ultraviolet initiator to initiate polymerization of the first polymer. The method further comprises measuring the enthalpy emitted by the second polymer formed by the second composition. The method then comprises comparing the enthalpy of the first polymer with the enthalpy of the second polymer and determining, based on the comparison, whether the UV initiator and the thermal initiator inhibit each other.

[0053] In some embodiments, the method further includes incubating the composition at a temperature of about 30°C to about 50°C before exposing the composition to ultraviolet light. In other embodiments, the method further includes exposing the composition to ultraviolet light for about 3 minutes to about 5 minutes. [Examples]

[0054] Example 1: Photo-DSC and DSC assays using UV initiator and thermal initiator combinations Since thermal initiators and UV initiators can interact and reduce each other's reactivity, assays were performed to evaluate the reactivity of various combinations of UV initiators and thermal initiators.

[0055] The reactivity of UV initiators in the presence of various thermal initiators was measured using optical DSC. After incubation at 40°C for 1 minute, the uncured gap filler material was exposed to UVA radiation for 3 minutes. Figure 3A shows the optical DSC spectra of the gap filler material after UV photocuring with UV initiator #1 and thermal initiators #3 and #4. [ka]

[0056] Figure 3B shows the optical DSC spectrum of the gap filler material after UV photocuring with a combination of UV initiator #2 (bottom) and thermal initiators #3 and #4 (top). [ka] Enthalpy (watts / gram) was measured as a function of time (minutes). As shown in Figures 3A and 3B, the combination of UV initiator #1 and thermal initiator #3 showed the maximum enthalpy emission, which coincided with the highest degree of polymerization for this combination.

[0057] The reactivity of thermal initiators in the presence of various UV initiators was measured using conventional DSC. Figure 3C shows the differential scanning calorimetry (DSC) spectrum of the gap filler material after thermal initiator #3 (top) and UV initiators #1 and #2 (top) were thermocured. Figure 3D shows the differential scanning calorimetry (DSC) spectrum of the gap filler material after thermal initiator #4 and UV initiators #1 and #2 were thermocured. Uncured materials were tested up to 300°C with a temperature increase of 20°C per minute. Enthalpy (watts / gram) was measured as a function of temperature (degrees Celsius). As shown in Figures 3C and 3D, thermal initiator #1 resulted in the strongest enthalpy emission of both UV initiators, which also coincides with the highest degree of polymerization.

[0058] Example 2: Monomer DSC assay Using a combination of UV initiator #1 and thermal initiator #3, the degree of curing and thermal events of various monomers were investigated using DSC. Figure 4 shows the DSC spectra of gap fillers containing monomers #1-5. Relative heat flow (watts / gram) was measured as a function of temperature (degrees Celsius) increasing by 20 degrees per minute up to 300 degrees. Dotted traces show each sample before curing, and solid traces show the samples after curing at 125°C for 16 hours. By measuring before and after curing, residual enthalpy could be compared to initial enthalpy, indicating the degree of curing (the amount of monomer that reacted with the polymer). As shown in Figure 4, certain monomers showed a higher degree of curing than others. Subsequently, these monomers were treated as preferred monomers because they reacted completely.

[0059] Example 3: FT-IR assay of curing degree of various monomers Fourier transform infrared (FT-IR) spectroscopy was used to study the degree of curing and thermal events of various monomers. As shown in Figure 5, FT-IR was performed on each sample after curing; the dotted traces show the spectrum before curing, and the solid traces show the spectrum after curing. These spectra were obtained at 3000 cm⁻¹ for the uncured samples. -1 It shows a band of unreacted oxirane groups, and in the cured material, it is 3750 cm⁻¹. -1 The presence of a hydroxide band indicates that polymerization of the target has occurred.

[0060] Example 4: CTE assay of ceramics Boron nitride and various amounts of ceramics, such as hollow glass spheres, were added to the gap filler composition along with the monomers shown and polymerized using a combination of UV initiator #1 and thermal initiator #3. Monomer #4 had a viscosity of 17 centipoise. Monomer #5 had a viscosity of 150 centipoise. Figure 6 shows the coefficient of thermal expansion (CTE) of gap fillers containing various amounts of boron nitride and glass sphere particles. Linear CTE (parts per million degrees Celsius) was measured as a function of the weight percentage of ceramic. The ceramics were mixed to match the CTE of the printed conductor. As shown in Figure 6, increasing the amount of ceramic particles decreased the overall CTE of the composite material, bringing it closer to the CTE of the printed conductor ink.

[0061] Compositions, methods, and articles may, by substitution, consist of, or essentially consist of any suitable material, step, or component disclosed herein. Compositions, methods, and articles may be formulated, additionally or by substitution, to lack or substantially lack material (or type), step, or component that is not otherwise necessary for achieving the function or purpose of the composition, method, and article.

[0062] All scopes disclosed herein include endpoints, which can be combined independently of each other (for example, the range “up to 25% by weight, or more specifically from 5% by weight to 20% by weight” includes endpoints and all intermediate values ​​of ranges such as “5% by weight to 25% by weight”). “Combinations” include blends, mixtures, alloys, reaction products, etc. Terms such as “first,” “second,” etc., are used to distinguish one element from another and do not indicate any order, quantity, or importance. The terms “a,” “an,” and “the” are not intended to imply a limitation of quantity and are to be interpreted as encompassing both singular and plural unless otherwise indicated herein or unless the context clearly contradicts this. “Or” means “and / or” unless otherwise specified. Where used herein, terms such as “comprising,” “including,” “having,” “containing,” and “involving” are understood to be non-restrictive, i.e., “including” is not limited, unless otherwise specified. As used herein, “about” or “approximately” means within an acceptable range of deviation of a particular value, as determined by a person skilled in the art, taking into account the stated value and the errors associated with the measurement of the problem and the measurement of a particular quantity (i.e., limitations of the measuring system). For example, “about” may mean within one or more standard deviations, or within ±10% or ±5% of the stated value. The use of any and all examples, or exemplary language (e.g., “etc.”), is intended merely to better illustrate the invention and, unless otherwise claimed, does not impose any limitation on the scope of the invention. No expression herein should be construed as indicating that an unclaimed element is essential to the practice of the invention, as used herein.

[0063] Wherever “aspects,” “embodiments,” etc., are used throughout this specification, it means that certain elements described in relation to an embodiment are included in at least one embodiment described herein, and may or may not be present in other embodiments. Furthermore, it should be understood that the elements described can be combined in any suitable way in various embodiments. “Those combinations” is open and includes any combination that optionally includes at least one of the enumerated components or characteristics with similar or equivalent components or characteristics.

[0064] Various embodiments of the present invention are described herein with reference to the relevant drawings. Alternative embodiments can be devised without departing from the scope of the invention. Various connections and positional relationships (e.g., above, below, adjacent, etc.) between elements are described in the following description and drawings, but as will be apparent to those skilled in the art, many of the positional relationships described herein are orientation-independent, even if the orientation is changed, as long as the described function is maintained. These connections and / or positional relationships can be direct or indirect unless otherwise specified, and the invention is not intended to limit in this respect. Thus, the joining of entities can refer to direct or indirect joining, and the positional relationship between entities can be direct or indirect positional relationship. As an example of an indirect positional relationship, the reference in this description to forming layer "A" above layer "B" includes a situation in which one or more intermediate layers (e.g., layer "C") are between layer "A" and layer "B", as long as the relevant properties and functions of layers "A" and "B" are not substantially altered by the intermediate layer(s).

[0065] The following definitions and abbreviations should be used in interpreting the claims and specification. Where used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains,” or “containing,” or any other variation thereof, are intended to extend to non-exclusive inclusion. For example, a composition, mixture, process, method, article, or apparatus containing a list of elements is not necessarily limited to these elements alone, and may include other elements not expressly enumerated, or other elements specific to such composition, mixture, process, method, article, or apparatus.

[0066] Furthermore, the term “typical” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or design described herein as “typical” should not necessarily be construed as being preferable or superior to other embodiments or designs. The terms “at least one” and “one or more” are understood to include any integer one or more, i.e., 1, 2, 3, 4, etc. The term “multiple” is understood to include any integer two or more, i.e., 2, 3, 4, 5, etc. The term “connection” may include indirect and direct “connections.”

[0067] References in the specification such as “one embodiment,” “embodiment,” and “exemplary embodiment” indicate that the described embodiment may include certain features, structures, or characteristics, but not all embodiments may include or may not include such features, structures, or characteristics. Furthermore, such phrases do not necessarily refer to the same embodiment. In addition, if certain features, structures, or characteristics are described in relation to an embodiment, it is presented that, whether explicitly described or not, the influence of such features, structures, or characteristics in relation to other embodiments is within the knowledge of those skilled in the art.

[0068] For the purposes of the following explanation, the terms “up,” “down,” “right,” “left,” “vertical,” “horizontal,” “top,” “bottom,” and their derivatives shall be those of the structures and methods described, as oriented in the drawings. The terms “lying on top,” “on top,” “located on top,” or “located above” mean that a first element, such as a first structure, is located on a second element, such as a second structure, and an intervening element, such as an interface structure, may be located between the first and second elements. The term “direct contact” means that a first element, such as a first structure, and a second element, such as a second structure, are connected at the interface of the two elements without any intermediate conductive, insulating, or semiconductor layer.

[0069] The terms “approximately,” “substantially,” and “nearly,” and their variations, are intended to include the degree of error relating to the measurement of a particular quantity based on equipment available at the time of filing. For example, “approximately” may include a range of ±8%, 5%, or 2% of a given value.

[0070] The flowcharts and block diagrams in the figures illustrate possible embodiments of the manufacturing and / or operating methods according to various embodiments of the present invention. The various functions / operations of the method are shown by blocks in the flowcharts. In some alternative embodiments, the functions noted in the blocks may be performed in a different order than noted in the figures. For example, two blocks shown consecutively may actually be executed substantially simultaneously, or blocks may sometimes be executed in reverse order depending on the functions they involve.

[0071] All means or step-plus-function elements in the following claims are intended to include any structures, materials, or actions for performing a function in combination with other claimed elements specifically claimed. The description of the present invention is presented for illustrative and explanatory purposes, but is not intended to be comprehensive or to limit the invention in any way disclosed. Many modifications and variations are obvious to those skilled in the art without departing from the scope and spirit of the invention. The embodiments have been selected and described to best illustrate the principles and practical applications of the invention and to enable others skilled in the art to understand the invention in terms of various embodiments, along with various modifications suitable for a particular intended use.

[0072] While preferred embodiments of the present invention have been described, those skilled in the art will understand that various improvements and enhancements can be made, both now and in the future, within the scope of the following claims. These claims should be interpreted as maintaining adequate protection for the invention as initially described.

Claims

1. A composition for manufacturing a filler, Ceramic particles, Liquid oxirane monomer, UV initiators that absorb ultraviolet light, and Contains a thermal initiator, The aforementioned ultraviolet initiator is a compound represented by the following structure: 【Chemistry 1】 The thermal initiator is a compound represented by the following structure: 【Chemistry 2】 The liquid oxirane monomer is selected from butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, tris(4-hydroxyphenyl)methane triglycidyl ether, resorcinol diglycidyl ether, bisphenol-A diglycidyl ether resins, novolac epoxy resins, and any combination thereof. A composition in which the ceramic particles are at least one selected from hexagonal boron nitride particles and glass spheres, and the ceramic particles are contained in the composition in an amount of 10 to 80% by weight.

2. The composition according to claim 1, wherein the oxirane monomer has the following structure. 【Transformation 3】

3. The composition according to claim 1, wherein the composition does not contain a solvent.

4. A chip-embedded printed circuit board, Cavities in printed circuit boards, The chip in the cavity of the printed circuit board, and A chip-embedded printed circuit board comprising a gap filler in the gap of the cavity for sealing the chip, the gap filler being a cured product of the composition according to claim 1, and having a thermal expansion coefficient of about 10 to about 150 parts per million degrees Celsius.

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