Anisotropic conductive adhesive and composition thereof

Abstract

The present invention provides an adhesive resin mixture having a controlled flowability, and a self-assembling anisotropic conductive adhesive including the adhesive resin mixture. The self-assembling anisotropic conductive adhesive including the adhesive resin mixture having a controlled flowability provides superior adhesion and contact resistance compared to conventional adhesives.

Description

[Technical Field]

[0001] The present invention relates to a self-assembling anisotropic conductive adhesive, and more particularly to a self-assembling anisotropic conductive adhesive with controlled flowability. [Background technology]

[0002] As information and communication devices have become more advanced in the 21st century, semiconductor packages have become increasingly more highly integrated, functional, cost-effective, and compact. Flexible displays, which have recently attracted attention as next-generation displays, have the advantage of being highly flexible and can be folded or rolled. As a result, research into the stable electrical and mechanical properties and high integration of the attached micro-components is progressing rapidly.

[0003] As a result, the development of high-density electronic packaging technology is progressing vigorously, and among the bonding technologies for such electronic packaging technology, bonding methods using anisotropic conductive adhesives (ACAs) have significant advantages such as lower process temperatures and simplified processes.

[0004] The anisotropic conductive adhesive is a material made by mixing metal powder or conductive polymer powder with a polymer binder. It combines the electrical, magnetic, and optical properties of metal with the mechanical properties and processability of polymer, making it an essential core material for connecting display panel glass, driver ICs to flexible PCBs, etc.

[0005] Such an anisotropic conductive adhesive generally contains solder particles, a reducing agent, and an adhesive resin. As can be seen from Figures 1 to 3, during the component mounting process, solder particles 31 in the anisotropic conductive adhesive 30 are positioned between the metal terminals of the substrate, so that the solder particles function as an electrical path, and adhesive resin 32 in the anisotropic conductive adhesive functions as an adhesive.

[0006] However, since the adhesive resin has fluidity, the adhesive resin and solder particles may be positioned between the metal terminals of the substrate during the component mounting process, but if the viscosity of the adhesive resin is too low, the solder particles and adhesive resin may all flow out of the gap between the metal terminals of the substrate and be lost, resulting in a weakened adhesive force. Conversely, if the viscosity of the adhesive resin is too high, the fluidity of the adhesive resin and solder particles may decrease, resulting in a problem that the adhesive resin and solder particles may not be positioned between the metal terminals of the substrate during the component mounting process.

[0007] Therefore, there is a need for a self-assembling anisotropic conductive adhesive that has appropriate viscosity, allows the adhesive resin and solder particles to be properly positioned between the metal terminals of the substrate, and has appropriate fluidity to prevent the solder particles and adhesive resin from flowing out during the component mounting process. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Republic of Korea Patent Registration No. 10-2062482 Summary of the Invention [Problem to be solved by the invention]

[0009] The technical problem that the present invention aims to achieve is to provide a self-assembling anisotropic conductive adhesive containing an adhesive resin whose fluidity is controlled within an appropriate range.

[0010] Another technical problem that the present invention aims to achieve is to provide a self-assembling anisotropic conductive adhesive that has excellent adhesive strength and low contact resistance.

[0011] The technical problems that the present invention aims to achieve are not limited to the above-mentioned technical problems, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present invention pertains from the following description. [Means for solving the problem]

[0012] In order to achieve the above technical objectives, one embodiment of the present invention provides an adhesive resin mixture for SACA, which comprises a first epoxy resin containing multiple epoxy groups in its molecule and a second epoxy resin having a viscosity of 100 cps or more and 500 cps or less.

[0013] In one embodiment of the present invention, the adhesive resin mixture for SACA may be characterized in that the weight ratio of the first epoxy resin to the second epoxy resin is 1:1.2 or more and 1:1.5 or less.

[0014] In addition, in an embodiment of the present invention, the adhesive resin mixture may be an adhesive resin mixture for SACA, characterized by having a viscosity of 500 cps or more and 100,000 cps or less in a temperature range of 70°C or more and 250°C or less.

[0015] In an embodiment of the present invention, the first epoxy resin may be any one selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, novolac type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, alicyclic epoxy resin, aliphatic polyglycidyl type epoxy resin, dimer acid modified epoxy resin, rubber modified epoxy resin, urethane modified epoxy resin, acrylic modified epoxy resin, and silicone modified epoxy resin.

[0016] In addition, in an embodiment of the present invention, the first epoxy resin may be an adhesive resin mixture for SACA, characterized in that the weight average molecular weight (Mw) is 30,000 or more and 60,000 or less.

[0017] In an embodiment of the present invention, the second epoxy resin may be any one selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, novolac type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, alicyclic epoxy resin, aliphatic polyglycidyl type epoxy resin, dimer acid modified epoxy resin, rubber modified epoxy resin, urethane modified epoxy resin, acrylic modified epoxy resin, and silicone modified epoxy resin.

[0018] In addition, in an embodiment of the present invention, the second epoxy resin may be an adhesive resin mixture for SACA, characterized in that the epoxy equivalent is 10 g / ep or more and 200 g / ep or less.

[0019] In order to achieve the above technical objectives, another embodiment of the present invention provides a self-assembling anisotropic conductive adhesive with controlled fluidity, comprising conductive solder particles and the adhesive resin mixture of paragraph 1, and characterized in that the adhesive resin mixture of paragraph 1 has a viscosity of 500 cps or more and 100,000 cps or less in a temperature range of 70°C or more and 250°C or less, thereby maximizing the positioning of the solder particles and the adhesive resin mixture between metal terminals of a substrate during a component mounting process.

[0020] In one embodiment of the present invention, the solder particles may be a self-assembling anisotropic conductive adhesive having controlled fluidity, characterized by having a melting point between the reaction initiation temperature and the curing temperature of the conductive adhesive resin mixture.

[0021] In addition, in an embodiment of the present invention, the solder particles may be a self-assembling anisotropic conductive adhesive with controlled fluidity, characterized in that the solder particles include any one or more selected from the group consisting of tin (Sn), copper (Cu), indium (In), silver (Ag), and bismuth (Bi). In addition, in an embodiment of the present invention, the solder particles may be a self-assembling anisotropic conductive adhesive with controlled fluidity, characterized in that the melting point is 70°C or more and 250°C or less.

[0022] In addition, in an embodiment of the present invention, the anisotropic conductive adhesive may be a self-assembling anisotropic conductive adhesive with controlled fluidity, characterized in that it is in a film or paste form. [Effects of the Invention]

[0023] According to an embodiment of the present invention, a self-assembling anisotropic conductive adhesive can be provided that includes an adhesive resin whose fluidity is controlled within an appropriate range, thereby maximizing the positioning of the adhesive resin and solder particles between the metal terminals of the substrate during the component mounting process step, and a self-assembling anisotropic conductive adhesive can be provided that has excellent adhesive strength and low contact resistance.

[0024] The effects of the present invention are not limited to the above effects, but include all effects that can be inferred from the configuration of the invention described in the detailed description of the present invention or the claims. [Brief explanation of the drawings]

[0025] [Figure 1] 10A and 10B are diagrams illustrating the state of the conductive adhesive positioned between substrates before the self-assembling anisotropic conductive adhesive is cured. [Figure 2] 10A and 10B are diagrams illustrating the process of hardening the adhesive resin and solder particles in the step of mounting the self-assembling anisotropic conductive adhesive. [Figure 3] FIG. 10 shows the connections located between the substrates after the self-assembled anisotropic conductor has cured. [Figure 4]1A and 1B are diagrams illustrating the state of a conductive adhesive positioned between substrates before a self-assembled anisotropic conductor provided by an embodiment of the present invention is cured. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein. In addition, to clearly illustrate the present invention in the drawings, parts that are not relevant to the description are omitted, and similar parts are designated by similar reference numerals throughout the specification.

[0027] Throughout this specification, when a part is said to be "connected (connected, contacted, or coupled)" to another part, this includes not only "directly connected" but also "indirectly connected" via another member therebetween. Furthermore, when a part is said to "comprise" a certain component, this does not mean that it excludes other components, but that it may further comprise other components, unless otherwise specified.

[0028] The terms used in this specification are merely used to describe specific embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprise" or "have" specify the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0029] Hereinafter, a self-assembling anisotropic conductive adhesive 30 with controlled fluidity according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0030] According to one embodiment of the present invention, conductive solder particles 31; Adhesive resin mixture described belowand a self-assembly anisotropic conductive adhesive (hereinafter referred to as "SACA") with controlled fluidity, which has a viscosity of 500 cps or more and 100,000 cps or less in a temperature range of 70°C or more and 250°C or less, thereby providing an effect of maximizing the positioning of the solder particles and the adhesive resin mixture (32) between the metal terminals (11) of the substrate during a component mounting process.

[0031] In the component mounting process step, the adhesive resin 32 in the adhesive resin mixture contained in the SACA 30 has fluidity and is therefore positioned between the metal terminals of the substrate, and as the adhesive resin in the SACA 30 hardens, it adheres the metal terminals of the substrate.

[0032] At this time, the fluidity of the adhesive resin 32 having fluidity must be within an appropriate numerical range, and if the fluidity is too low, the fluidity of the adhesive resin 32 and the solder particles 31 is hindered, and they may not even be positioned between the metal terminals 21 of the substrate. Conversely, if the fluidity is too high, the adhesive resin 32 and the solder particles 31 may detach from between the metal terminals 21 of the substrates 10, 20 during the step of applying heat and pressure to bond them, due to the excessive fluidity, and ultimately the adhesion between the substrates 10, 20 will not occur, resulting in a decrease in the stability and reliability of the product.

[0033] Therefore, as described above, one embodiment of the present invention provides an SACA 30 that enhances the adhesive strength of the substrate by controlling the fluidity of the adhesive resin 32.

[0034] The adhesive resin 32 of the SACA 30 with adjusted fluidity will now be described.

[0035] In the present invention, the adhesive resin 32 of the SACA 30 with controlled fluidity is mainly composed of an adhesive resin mixture for SACA in the embodiment described below. However, the adhesive resin is not limited to the adhesive resin mixture for SACA in the embodiment described below. Mixtures that are the same as or equivalent to the adhesive resin mixture provided in one embodiment of the present invention, and adhesive resins that provide the same or equivalent effects, should all be considered to fall within the scope of the present invention.

[0036] The solder particles of SACA30 with controlled fluidity will be described below.

[0037] The role of the solder particles will be explained below.

[0038] The solder particles used in the present invention may be conductive particles. By using such conductive particles, the solder particles will ultimately be positioned between the substrates and will act as an electrical path between the electrodes of the substrates.

[0039] The melting point of the solder particles will be explained below.

[0040] When electronic components are heated during the mounting process, the solder particles must melt first to form a connection before the thermosetting resin hardens, and the viscosity of the thermosetting resin must be reduced to allow the molten solder particles to smoothly agglomerate in the heated state. Therefore, it is preferable that the melting point of the solder particles be between the reaction start temperature and the hardening end temperature of the thermosetting resin.

[0041] Therefore, the solder particles may be low-melting-point solder particles having a melting point of 70° C. or higher and 250° C. or lower. By using such low-melting-point solder particles, it is possible to suppress or prevent damage to various members of electronic components due to thermal history.

[0042] The structure of the solder particles will be described below.

[0043] The solder particles may include two or more selected from the group consisting of tin (Sn), indium (In), copper (Cu), silver (Ag), and bismuth (Bi). For example, the solder particles may be, but are not limited to, 60Sn / 40Bi, 52In / 48Sn, 97In / 3Ag, 57Bi / 42Sn / 1Ag, 58Bi / 42Sn, and 96.5Sn / 3.5Ag. However, the present invention is not limited to metal particles, and any other configuration that can be easily modified or adopted by a person skilled in the art to achieve the effects of the present invention, such as a conjugated polymer conductive polymer, should be construed as belonging to the present invention.

[0044] Furthermore, when the solder particles are metal elements, they easily form an oxide film on their surfaces upon contact with oxygen in the atmosphere. When an anisotropic conductive adhesive containing solder particles is used to mount electronic components such as semiconductor chips, the oxide film can cause problems such as unstable contact resistance, low conductivity, and unstable bonding strength, resulting in poor electrical characteristics. To address this issue, solder particles with improved wetting properties due to the addition of a reducing agent such as a carboxylic acid during the step of mixing and dispersing the solder particles and binder resin can be used to strengthen the bond with wiring or signal line contacts.

[0045] That is, when the solder particles are metal elements, there is a possibility that an oxide film may be formed on the solder particles, and therefore it is preferable that the oxide film on the solder particles has been removed or controlled by a reducing agent.

[0046] The particle size of the solder particles will be described below.

[0047] The size of the solder particles can be selected depending on the size (egpitch) of the conductive pattern to be applied, and as the size of the conductive pattern increases, solder particles with larger particle sizes can be used.

[0048] The mixing ratio of the solder particles will be explained below.

[0049] Taking into consideration fluidity and wettability, the solder particles may be contained in a ratio of 5 to 60% by volume of the total amount of the fluidity-adjusted SACA 30. If the content is less than 5% by volume, there is a risk that a lack of solder particles will prevent connection between terminals, and if the content is more than 60% by volume, there is a risk that excessive solder particles will remain, causing a bridge due to the connection between adjacent terminals, resulting in a short circuit.

[0050] Hereinafter, the physical properties and characteristics of the fluidity-controlled SACA30 will be described.

[0051] FIG. 4 is a diagram illustrating the state of a conductive adhesive positioned between substrates before the self-assembled anisotropic conductor provided according to one embodiment of the present invention is cured.

[0052] The fluidity-adjusted SACA30 preferably has a viscosity of 500 cps or more and 100,000 cps or less in the temperature range of 70°C or more and 250°C or less, as described above.

[0053] As described above, in the component mounting process, the solder particles and adhesive resin must be positioned between the metal terminals of the substrate, as shown in Figure 4. If the viscosity of the adhesive resin is less than 500 cps, the viscosity of the adhesive resin will be too low and the fluidity will increase, causing the solder particles and adhesive resin to flow out of the gap between the metal terminals of the substrate and be lost during the component mounting process, weakening the adhesive strength of the final product. Conversely, if the viscosity of the adhesive resin is more than 100,000 cps, the viscosity of the adhesive resin will be too high and the fluidity will decrease, causing the solder particles and adhesive resin to be unable to be positioned between the metal terminals of the substrate during the component mounting process, weakening the adhesive strength of the final product. Therefore, it is preferable that the anisotropic conductive adhesive have a viscosity of 500 cps to 100,000 cps in the temperature range of 70°C to 250°C.

[0054] The fluidity-adjusted SACA30 can be used in film or paste form, but film-type conductive adhesives are preferred because they offer advantages over paste-type adhesives in terms of mounting costs, thickness control, and quality control, such as adhesive reliability, during mounting on a substrate.

[0055] Furthermore, as will be seen from the experiments described below, the fluidity-controlled SACA30 has an adhesive strength of 2.0 to 3.0 kgf / cm and excellent contact resistance, and is therefore more likely to be used as a mounting conductive adhesive in various industrial fields such as substrates, displays, and semiconductors than conventional anisotropic conductive adhesives.

[0056] An adhesive resin mixture for SACA provided according to another embodiment of the present invention will now be described.

[0057] In order to solve the above technical problems, another embodiment of the present invention provides an adhesive resin mixture for SACA, comprising: a first epoxy resin containing multiple epoxy groups in its molecule; and a second epoxy resin having a viscosity of 100 cps to 500 cps at 20°C to 30°C.

[0058] Furthermore, since the adhesive resin mixture for the SACA must function to properly position the solder particles and adhesive resin between the metal terminals of the substrate during the component mounting process as described above, it is preferable that the adhesive resin mixture for the SACA has a viscosity of 500 cps or more and 100,000 cps or less in the temperature range of 70°C or more and 250°C or less, which is the melting temperature of the solder particles.

[0059] The constituent compounds of the adhesive resin will be described below.

[0060] The adhesive resin may include an adhesive resin mixture containing a plurality of epoxy resins, and the adhesive resin mixture may include a first epoxy resin containing a plurality of epoxy groups in its molecule and a second epoxy resin having an epoxy equivalent of 10 g / ep or more and 200 g / ep or less.

[0061] In this specification, "epoxy equivalent weight" means the molecular weight per epoxy group (g / eqiv) (meaning the average molecular weight divided by the number of epoxy groups per molecule). Therefore, when the average molecular weight is fixed, the equivalent weight decreases as the number of epoxy groups per molecule increases, and vice versa.

[0062] In this case, the first epoxy resin contains a plurality of epoxy groups in the molecule, and the second epoxy resin has a viscosity of 100 cps to 500 cps at 20°C to 30°C, preferably 100 cps to 500 cps at room temperature of 25°C, thereby making it possible to adjust the viscosity, self-assembling property, and physical properties of the composition.

[0063] The weight ratio of the first epoxy resin to the second epoxy resin may be 1:1 or more and 1:2 or less, and preferably 1:1.2 or more and 1:1.5 or less. If the mixing ratio of the first epoxy resin to the second epoxy resin is less than 1:1 and an excessive amount of the first epoxy resin is added, the viscosity becomes too high (beyond the suggested viscosity range), making self-assembly difficult. If the mixing ratio is more than 1:2 and an excessive amount of the second epoxy resin is added, the above-mentioned physical properties may not be achieved. Therefore, to avoid the above-mentioned problems, the mixing ratio of the first epoxy resin to the second epoxy resin may be 1:1 or more and 1:2 or less, and to obtain the best results, a mixing ratio of 1:1.2 or more and 1:1.15 or less is preferred.

[0064] The first epoxy resin will be described below.

[0065] The first epoxy resin preferably has epoxy groups bonded to both chains, thereby ensuring the properties of epoxy groups, such as high adhesive strength, chemical resistance, moisture absorption resistance, and high insulation.

[0066] The first epoxy resin may be any one selected from the group including, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, novolac type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, alicyclic epoxy resin, aliphatic polyglycidyl type epoxy resin, dimer acid modified epoxy resin, rubber modified epoxy resin, urethane modified epoxy resin, acrylic modified epoxy resin, and silicone modified epoxy resin, but is not limited to the above examples.

[0067] When the first epoxy resin is mixed, the mixing amount may be determined based on the weight ratio, and in this case, the weight ratio may be a weight average molecular weight, and the weight average molecular weight (Mw) of the first epoxy resin to be mixed may be 30,000 or more and 60,000 or less.

[0068] If the weight average molecular weight of the first epoxy resin is less than 30,000, the final cured product may have excessive brittleness due to low toughness.

[0069] Conversely, as the weight-average molecular weight increases, the maximum crosslink density achievable by the reaction of epoxy groups decreases, and heat resistance tends to decrease. Therefore, when the weight-average molecular weight of the first epoxy resin exceeds 60,000, the maximum crosslink density achievable by the reaction of epoxy groups decreases, resulting in a problem of a decrease in the final degree of cure, and a problem of a decrease in heat resistance, resulting in unstable physical properties after curing.

[0070] In addition, the first epoxy resin preferably has a softening point of 130° C. to 150° C. When a first epoxy resin having a softening point in the above temperature range is used, high heat resistance can be ensured.

[0071] If the composition is made up of only epoxy with low viscosity and softening point to ensure fluidity during bonding of SACA or for other purposes, it is very easy to adjust the fluidity, but there may be a problem that the physical properties become unstable after curing due to low heat resistance.

[0072] The second epoxy resin will be described below.

[0073] If the first epoxy resin is used alone, the viscosity is too high at all temperatures between 70°C and 250°C, and at the melting temperature of the solder at which self-assembly occurs, making self-assembly of the adhesive resin mixture difficult. Therefore, it is necessary to lower the viscosity of the adhesive resin mixture for SACA to facilitate self-assembly, and the second epoxy resin is included for the above purpose.

[0074] In addition, the second epoxy resin must function as a diluent to reduce the viscosity of the adhesive resin mixture for SACA, and must not impair the overall physical properties of the adhesive resin mixture for SACA, thereby ensuring high reliability after curing of the adhesive resin mixture for SACA. Therefore, it is preferable to use an epoxy resin with high heat resistance and glass transition temperature.

[0075] The second epoxy resin may be any one selected from the group including bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, fluorene type epoxy resin, novolac type epoxy resin, phenol novolac type epoxy resin, orthocresol novolac type epoxy resin, glycidyl ether type epoxy resin, glycidyl amine type epoxy resin, alicyclic epoxy resin, aliphatic polyglycidyl type epoxy resin, dimer acid modified epoxy resin, rubber modified epoxy resin, urethane modified epoxy resin, acrylic modified epoxy resin, and silicone modified epoxy resin, but is not limited to the above examples.

[0076] In this case, the second epoxy resin may have an epoxy equivalent of 10 g / ep or more and 200 g / ep or less. If the epoxy equivalent is less than 10 g / ep, the number of reactive epoxy groups will be too large, resulting in some remaining unreacted and thus the generation of impurities. Conversely, if the epoxy equivalent is more than 200 g / ep, the number of reactive epoxy groups will be too small, resulting in the problem of impurities. Therefore, it is most preferable that the epoxy equivalent is 10 g / ep or more and 200 g / ep or less.

[0077] The present invention will be described in more detail below with reference to Production Examples, Comparative Examples and Experimental Examples, but the present invention is not limited to the following Production Examples and Experimental Examples.

[0078] Preparation Example 1 - Preparation of adhesive resin mixture for SACA In Preparation Example 1, various adhesive resin mixtures were prepared by mixing a phenol novolac epoxy resin as the first epoxy resin and a bisphenol F epoxy resin as the second epoxy resin. The specific preparation process is as follows.

[0079] Adhesive resin mixtures for 20 SACAs were prepared by mixing a phenolic novolac epoxy resin with a weight average molecular weight (Mw) of 50,000 and a bisphenol F epoxy resin with a weight average molecular weight (Mw) of 40,000 in weight ratios of 1:0.1, 1:1.1, ..., 1:1.9, and 1:2.0, and the mixtures were mixed at 30°C for 30 minutes.

[0080] Table 1 below summarizes the above percentages.

[0081] [Table 1]

[0082] According to the above process, in Preparation Example 1, an adhesive resin mixture was successfully prepared.

[0083] Preparation Example 2 - Preparation of SACA with controlled fluidity In Preparation Example 2, a self-assembling anisotropic conductive adhesive was produced containing the adhesive resin mixture produced in Preparation Example 1 and solder particles containing Bi and In metals. The specific production process is as follows:

[0084] The adhesive resin mixture (50 wt%) of entries 1 to 20 in Table 1 prepared in Preparation Example 1, solder particles (30 wt%), a reducing agent (5 wt%), a curing agent (10 wt%), and a silane coupling agent (5 wt%) were mixed to prepare SACA.

[0085] At this time, the first epoxy resin and the second epoxy resin were mixed at 30° C. for 30 minutes to form a mixture, and then other additives were further mixed into the mixture at 25° C. for 10 minutes.

[0086] Then, the mixture was mixed with the pretreated solder particles and a reducing agent at 25° C. for 10 minutes, and finally, the mixture was mixed with a curing agent at 25° C. for 1 minute.

[0087] At this time, the mixing process was all carried out using a paste mixer.

[0088] As a result, a self-assembling anisotropic conductive adhesive was successfully produced.

[0089] Preparation Example 3 - Preparation of SACA with controlled flow properties having different solder particle compositions In Preparation Example 3, various SACAs were manufactured by the same method as in Preparation Example 2, except that the Bi and In metals constituting the solder particles were replaced with 30 wt % Sn, Ag, and Cu metals.

[0090] By changing the metal element, we were able to manufacture SACA containing various solder particles, which means that users can manufacture anisotropic conductive adhesive containing any metal element they desire.

[0091] Experimental Example 1 - Confirmation of viscosity of adhesive resin mixture In this Experimental Example 1, the viscosity of the adhesive resin mixture produced in Production Example 1 above was measured.

[0092] The specific experimental method is as follows. The experiment was carried out by using a rheometer to measure the minimum viscosity value in the temperature range of 70°C to 250°C.

[0093] [Table 2]

[0094] As can be seen from Table 2 above, the closer the mixing ratio of bisphenol F epoxy to phenol novolac epoxy is to 1:1, the higher the viscosity, and the closer it is to 1:2, the lower the viscosity.

[0095] Furthermore, as will be seen from the experimental examples described later, the adhesive resin mixture produced in Production Example 1 is the most suitable adhesive resin for a self-assembling anisotropic conductive adhesive. Ratio of 1:1.2 or more and 1:1.5 or less is found to be the optimal ratio.

[0096] Experimental Example 2 - Adhesion Strength Verification Experiment In Experimental Example 2, adhesive strength was tested using various self-assembling anisotropic conductive adhesives prepared in Preparation Example 2 above.

[0097] The specific experimental method is as follows: 1.Equipment used: UTM (Universal Testing Machine) 2. Substrates used: PCB and FPCB adhesive (200 pitch) 3. Experimental conditions: Tensile speed 50 mm / min, 90° peel

[0098] Table 3 below is a summary of the experimental results of Experimental Example 2.

[0099] [Table 3]

[0100] As can be seen from Table 3 above, the material with the best adhesive strength of 2.0 to 3.0 kgf / cm was SACA, which was a mixture of phenol novolac epoxy and bisphenol F epoxy in a ratio of 1:1.2 or more and 1:1.5 or less.

[0101] This experimental example revealed that the best adhesive strength was obtained when phenol novolac epoxy and bisphenol F epoxy were mixed in a ratio of 1:1.2 to 1:1.5.

[0102] Experimental Example 3 In Experimental Example 3, various self-assembling anisotropic conductive adhesives manufactured in Manufacturing Example 2 above were used to test their surface resistance.

[0103] The specific experimental method is as follows. As can be seen from the above experimental results, the surface resistance is generally at a level of 1 or less, and is generally excellent.

[0104] Experimental Example 4 In Experimental Example 4, an adhesive resin mixture was prepared by changing only the weight average molecular weight of the first epoxy resin in Preparation Example 1, and a self-assembling anisotropic conductive adhesive containing these was prepared, and an experiment was conducted to confirm its adhesive strength.

[0105] The specific experimental method is as follows. 1.Equipment used: UTM (Universal Testing Machine) 2. Substrates used: PCB and FPCB adhesive (200 pitch) 3. Experimental conditions: Tensile speed 50 mm / min, 90° peel

[0106] [Table 4]

[0107] As can be seen from Table 4 above, the first epoxy resin provides the best adhesive strength when the weight average molecular weight is 30,000 or more and 60,000 or less.

[0108] This is because when a first epoxy resin having the above weight average molecular weight is used, the effect of providing low brittleness and high crosslink density is achieved.

[0109] Experimental Example 5 In Experimental Example 5, an adhesive resin mixture was prepared by changing only the epoxy equivalent of the second epoxy resin in Preparation Example 1, and a self-assembling anisotropic conductive adhesive containing the mixture was prepared, and its physical properties were tested.

[0110] The specific experimental method is as follows. 1.Equipment used: UTM (Universal Testing Machine) 2. Substrates used: PCB and FPCB adhesive (200 pitch) 3. Experimental conditions: Tensile speed 50 mm / min, 90° peel

[0111] [Table 5]

[0112] As can be seen from Table 5 above, the second epoxy resin provides the best effect when the epoxy equivalent is 100 g / ep or more and 200 g / ep or less.

[0113] This is because when a second epoxy resin having the above epoxy equivalent weight is used, the number of reactive epoxy groups is optimized, so that most of the epoxy groups participate in the reaction and none remain as impurities.

[0114] The above description of the present invention is for illustrative purposes only, and a person skilled in the art to which the present invention pertains can easily modify the present invention into other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments are illustrative in all respects and are not limiting. For example, each component described as a single component may be implemented in a distributed form, and similarly, each component described as distributed may be implemented in a combined form.

[0115] The scope of the present invention is defined by the claims that follow, and all modifications and variations that fall within the meaning and scope of the claims and their equivalents are included within the scope of the present invention. [Explanation of symbols]

[0116] 10: Second board 11: Connection terminal 20: First board 21: Electrode terminal 30: Self-assembling anisotropic conductive adhesive 31: Solder particles 32: Adhesive resin contained in adhesive resin mixture 33: Hardener 40:Connector 50: Cured resin layer

Claims

1. A first epoxy resin comprising a phenol novolac epoxy resin; a second epoxy resin comprising a bisphenol F epoxy resin and having a viscosity of 100 cps or more and 500 mPa·s or less at 20°C or more and 30°C or less; Including, the second epoxy resin has an epoxy equivalent of 10 g / ep or more and 200 g / ep or less; The weight ratio of the first epoxy resin to the second epoxy resin is 1:1.2 or more and 1:1.5 or less. An adhesive resin mixture for self-assembling anisotropic conductive bonding, characterized in that:

2. The adhesive resin mixture has a viscosity of 500 cps or more and 100,000 cps or less in the temperature range of 70°C or more and 250°C or less. The adhesive resin mixture for self-assembling anisotropic conductive adhesive according to claim 1.

3. The first epoxy resin has a weight average molecular weight (Mw) of 30,000 or more and 60,000 or less. The adhesive resin mixture for self-assembling anisotropic conductive adhesive according to claim 2.

4. Conductive solder particles; The adhesive resin mixture of claim 1, During the component mounting process, the solder particles and the adhesive resin mixture are positioned as close as possible between the metal terminals of the substrate. A self-assembling anisotropic conductive adhesive having controlled fluidity.

5. The solder particles have a melting point between the reaction initiation temperature and the hardening temperature of the adhesive resin mixture for the self-assembling anisotropic conductive adhesive. The self-assembling anisotropic conductive adhesive with controlled flowability according to claim 4 .

6. The solder particles include at least one selected from the group consisting of tin (Sn), copper (Cu), indium (In), silver (Ag), and bismuth (Bi). The self-assembling anisotropic conductive adhesive with controlled flowability according to claim 4 .

7. The solder particles have a melting point of 70°C or more and 250°C or less. The self-assembling anisotropic conductive adhesive with controlled flowability according to claim 4 .

8. The adhesive resin mixture for the self-assembling anisotropic conductive adhesive is in the form of a film or a paste. The self-assembling anisotropic conductive adhesive with controlled flowability according to claim 4 .

Images