KR102141721B1 - High efficiency heat transfer adhesive materials and manufacturing thereof - Google Patents

Abstract

The present invention relates to a high-efficiency heat dissipation adhesive material and a method for manufacturing the same, and more specifically, by designing different bulk properties and surface properties of the material, realizing excellent surface adhesion properties while maintaining excellent heat resistance and reliability By minimizing the contact resistance, it is possible to have a high efficiency heat dissipation performance. In order to selectively vary the surface properties of the material, a spontaneous surface separation phenomenon is applied thermodynamically without external manipulation. In order to separate the resin having excellent adhesiveness from the substrate to the surface, when it has a relatively low content, low surface energy, and low molecular weight compared to the resin forming the bulk, it is spontaneously separated to the surface during the manufacturing and drying process of the material. do.

Description

High-efficiency heat dissipation adhesive material and its manufacturing method{HIGH EFFICIENCY HEAT TRANSFER ADHESIVE MATERIALS AND MANUFACTURING THEREOF}

The present invention relates to a high-efficiency heat dissipation adhesive material and a method for manufacturing the same, more specifically, non-polar (low surface energy) and low molecular weight resins are concentrated on both surfaces of the adhesive sheet by spontaneous surface separation between the manufacturing processes of the adhesive sheet. It relates to a high-efficiency heat dissipation adhesive material that can maximize the thermal conductivity by further improving the wettability with the two substrate surfaces to be bonded, thereby minimizing the contact resistance at the substrate surface, the biggest bottleneck of heat transfer, and a method for manufacturing the same.

In general, heat is generated during use of an electronic component or device. In particular, as the use of portable module devices has rapidly increased, light-emitting characteristics at the device level and electronic components or At the IC package level, awareness and demand for heat dissipation characteristics are increasing.

This IC package uses a heat spreader to dissipate the heat generated by the chip or inserts an interfacial filling material for heat transfer between heat dissipation fins to achieve efficient heat transfer, thereby preventing performance degradation due to the temperature rise of the package. Doing. Such an interfacial filling material is usually a composite material containing high thermal conductivity inorganic additives in a polymer resin.

Due to the non-uniform bond line thickness (BLT) problem of a paste type heat transfer interface filling material used in the past, a sheet or film type heat transfer interface filling material has been developed (Korean Patent Publication No. 2010-0038115) No. 2011-7016122, No. 2004-0023520), in the case of such a heat transfer/heat dissipation adhesive sheet, unlike the paste form, the interfacial adhesion is poor, and thus the surface of the chip, heat spreader or heat sink fin cannot be filled. In other words, there is a problem in that the air conductivity includes the air interface having the worst thermal conductivity, and when applied to the IC package, the heat transfer efficiency is significantly lower than the heat transfer efficiency of the actual material.

In the end, if less heat transfer filler is used to improve the interfacial adhesion of the heat transfer sheet, the interfacial adhesion may be improved, but there is a mutually inconsistent relationship that does not achieve sufficient thermal conductivity. Due to this relationship, in itself, when the sheets having excellent thermal conductivity are bonded to actual substrates, there are problems that the thermal conductivity efficiency is halved to three times or more.

Korea Patent Publication No. 2010-0038115 Korea Patent Publication No. 2011-7016122 Korea Patent Publication No. 2004-0023520

The present invention has been devised to solve the above problems, and the object of the present invention is a bulk state based on a bulk content of a heat transfer filler of a conventional heat transfer or heat dissipation adhesive material or a packing model of Horsesfield. Designed from the viewpoint of filling only, it deviates from the method of sacrificing the mutually contrary characteristics of thermal conductivity and contact resistance, and maximizes the thermal conductivity of the bulk while minimizing the contact resistance at the interface and improving the interfacial thermal conductivity. It is to provide a high-efficiency heat dissipation adhesive material and a manufacturing method thereof.

The above and other objects and advantages of the present invention will become more apparent from the following description of the preferred embodiment.

The above object is achieved by a high-efficiency heat dissipation adhesive material, characterized in that it comprises a resin having excellent adhesion to the substrate and a resin forming a bulk as a resin having excellent heat resistance.

Here, the resin excellent in adhesion to the substrate is a non-polar resin, and the resin forming the bulk is characterized in that it is a polar resin.

Preferably, the resin having excellent adhesion to the substrate is at least one selected from acrylic resins or silicone resins, and the resin forming the bulk is at least one selected from epoxy resins, phenoxy resins, polyimide resins, and polyamideimide resins. It is characterized by.

Preferably, the resin having excellent adhesion to the substrate minimizes contact resistance with the substrate, and the resin forming the bulk maintains excellent reliability by forming bulk properties in the middle of the material.

Preferably, the resin having excellent adhesion to the substrate is characterized in that the weight average molecular weight is 3,000 or more and 10,000 or less, and the surface energy is 25 mJ/m ² or less.

Preferably, the resin forming the bulk is characterized in that the weight average molecular weight is 50,000 or more, 1,000,000 or less, and the surface energy is 35 mJ/m ² or more.

Preferably, the resin having excellent adhesion to the substrate is 10% by weight or more and 30% by weight or less relative to the weight of the resin forming the bulk, and the difference in surface energy of the heterogeneous resin is 10 mJ/m ² or more. .

Preferably, the surface energy of the support used for drying by coating the resin having excellent adhesion to the substrate and a resin mixed with the resin forming the bulk is 15 mJ/m ² or less.

In addition, the purpose is to use a resin of a resin that forms a bulk with a resin having excellent adhesion to the substrate, but the resin having excellent adhesion to the substrate is spontaneously formed of the bulk during the drying process after coating of the material. It is achieved by a method of manufacturing a high-efficiency heat-radiating adhesive material, characterized in that the high-efficiency heat-radiating adhesive material is produced by separating both surfaces.

Here, the resin having excellent adhesion to the substrate is at least one selected from acrylic resins or silicone resins, and the resin forming the bulk is at least one selected from epoxy resins, phenoxy resins, polyimide resins, and polyamideimide resins. Is done.

Preferably, the resin having excellent adhesion to the substrate minimizes contact resistance with the substrate, and the resin forming the bulk maintains excellent reliability by forming bulk properties in the middle of the material.

Preferably, a support is used for drying by coating a resin mixed with a resin having excellent adhesion to the substrate and a resin forming the bulk, and the surface energy of the support is 15 mJ/m ² or less.

According to the present invention, in the dry thermal process of manufacturing the adhesive material or sheet, non-polar low molecular adhesive resin is spontaneously separated from the polar polymer adhesive resin and is relatively concentrated on both surfaces of the adhesive material, thereby requiring heat transfer. It has the effect of being able to realize higher thermal conductivity by maximizing the adhesion with the substrates.

1 is a schematic view showing a state in which different types of resins are uniformly mixed in a material immediately after coating.
2 is a schematic view showing the state of the high-efficiency heat dissipation adhesive material according to the present invention in which the resin composition of the surface and the bulk is changed by spontaneous surface separation of the different resins during the drying process after coating.

Hereinafter, the present invention will be described in detail with reference to examples and drawings of the present invention. These examples are only provided by way of example to illustrate the present invention in more detail, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control.

Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

All percentages, parts, ratios, etc. are by weight unless otherwise stated. Also, if an amount, concentration, or other value or parameter is given as one of a range, a preferred range, or a list of preferred upper and lower limits, this is any upper range limit or preferred value and any lower limit, regardless of whether the ranges are disclosed separately. It should be understood that all ranges formed from any pair of range limits or preferred values are specifically disclosed. When a range of numerical values is referred to herein, unless stated otherwise, that range is intended to include the endpoints and all integers and fractions within the range. It is intended that the scope of the invention not be limited to the specific values recited when defining a range.

When the term “about” is used to describe the end point of a value or range, it should be understood that the present disclosure includes the specific value or end point mentioned.

As used herein, "comprise", "comprising", "include", "including", "containing", "~ The terms characterized by, "has", "having", or any other variation thereof, are intended to cover non-exclusive inclusions. For example, a process, method, article, or apparatus that includes a list of elements is not necessarily limited to only those elements, and may include other elements not explicitly listed or inherent to such a process, method, article, or apparatus. It might be. Also, unless explicitly stated to the contrary, "or" refers to a generic'or' and not to an exclusive'or'.

It should be readily understood that if the applicant has defined the invention or parts thereof in open terms such as "comprising", the description should also be interpreted as describing the invention using the term "consisting essentially of" unless otherwise specified. do.

The present invention relates to a high-efficiency heat dissipation adhesive material and a method for manufacturing the same, wherein the heat conduction characteristics of the material itself are described so as to realize a similar level of heat conduction characteristics as much as possible even in the state where the actual material is applied between the high heat source and the low heat source substrate. It is characterized by having excellent adhesion to and.

In order to realize the above characteristics, the present invention does not merely improve the thermal conductivity of the bulk state of the adhesive material in a bulk state through the formation of heat transfer paths or the content of heat transfer fillers, but the thermal conductivity and heat resistance of the bulk state are halved. In order to induce spontaneous phase separation or surface separation of heterogeneous adhesive resins in the adhesive material without imparting, it is intended to impart additional surface adhesion properties so that air resistance can be minimized through improved adhesion to the actual substrate surface. However, in this specification, spontaneous phase separation is mainly described, but the present invention may be applied to involuntary phase separation.

In the case of the existing heat dissipation adhesive material (for example, Korean Patent Publication No. 10-2005-0104280, see FIG. 1, Korean Patent Publication No. 10-2007-0003626), the content or blending ratio in terms of heat transfer fillers that influence heat transfer. Alternatively, attempts have been made to maximize heat transfer through adjustment of orientation, etc., which may improve the thermal conductivity of the heat dissipation adhesive material itself, but for the contact resistance with the substrate, which is the most restrictive factor in terms that should be used between actual substrates. Since it is not considered, in most cases, the efficiency is reduced to less than half when applied to an actual device.

In the composition of the general heat dissipation adhesive material, most of the heat transfer fillers are inorganic particles and cannot contribute to adhesion to the substrate, and an organic adhesive resin that forms these heat transfer fillers in a sheet form may play a role. As a result, if the content of the heat transfer filler is increased by focusing on heat transfer, the proportion of the heat transfer filler at the interface increases, so that the contact resistance increases. However, if the properties of the resin are improved by minimizing the content of the heat transfer filler, however, the contact resistance may be reduced, but the desired heat transfer efficiency cannot be obtained due to a decrease in the thermal conductivity of the bulk material itself. Due to this conflicting relationship, it is not possible to achieve a performance exceeding a certain thermal conductivity using only a design method capable of increasing the thermal conductivity of the bulk material while minimizing contact resistance through controlling the ratio of the heat transfer filler and the resin.

Of course, for example, it is possible to maximize the adhesion to some extent by using a silicone resin, which is the resin having the best adhesion to the substrate among the adhesive resins. However, when using a silicone resin, exposure to heat for a long time as a heat radiation adhesive material With respect to physical/chemical stability, there are limitations, and as a non-polar property, there is a problem in that interface adhesion with a heat transfer filler which is generally polar is poor.

However, when using an epoxy, polyimide or polyamideimide-based resin having excellent heat resistance and polarity characteristics, high temperature/high pressure working conditions are required for excellent adhesion to the substrate, but for delicate electronic parts. In most cases, the heat dissipation adhesive materials used cannot be applied.

For this reason, it is necessary to design a special material capable of simultaneously satisfying basic heat resistance (durability) as a heat dissipation adhesive material and adhesion to a substrate. However, it is needless to say that such a design should not be a problem in terms of productivity or price because the design is complicated.

The high-efficiency heat dissipation adhesive material according to the present invention is characterized in that it improves both bulk and interfacial properties of a material by realizing excellent heat resistance or durability and adhesion to an excellent substrate of the material itself, which could not be realized simultaneously in a general adhesive material. do. That is, the thermodynamic properties of resins with low surface energy and low molecular weight spontaneously move to the surface during the drying process after coating by mixing heterogeneous adhesive materials with different polar/non-polar or surface energy and different molecular weights at an asymmetric ratio. It is possible to control the properties of the bulk and the interface at the same time by using. It is to use different kinds of resins with different polarity and molecular weight as the main binder.

Among the resins, resins that form bulks exhibiting bulk characteristics have high polarity or high surface energy (> 35 mJ/m ² ), such as epoxy (phenoxy), polyimide, polyamideimide resin, etc., which have excellent heat resistance or durability. Can be used.

On the other hand, a resin having excellent adhesion to a substrate that controls interfacial properties is non-polar or has a low surface energy (< 25 mJ/m ² ), which can show the property of being separated from the resins during the coating process in the air and moving to the interface. Acrylic or silicone resin can be used.

In addition, the surface energy difference of the heterogeneous resin is preferably 10 mJ/m ² or more.

However, the weight average molecular weight of the resin having excellent adhesion to the substrate moving to the surface is preferably 3,000 or more and 10,000 or less. If it is less than 3,000, the effect of moving to the surface is excellent, but it can cause problems such as outgas when operating in a high-temperature process or a high-temperature environment for a long time to adhere to the substrate. There is a problem that a sufficient amount of a level capable of realizing the adhesion is not separated from the surface.

In addition, it is preferable that the resin forming the bulk property or forming the bulk that does not move to the surface has a weight average molecular weight of 50,000 or more and 1,000,000 or less so as to be stable even for a long period of heat exposure. If it is less than 50,000, it is insufficient to form sufficient heat-resistance properties due to lack of cohesion even after the curing reaction of the resin, and if it is more than 100,000, it is impossible to induce the required surface separation phenomenon by inhibiting the moving property of the resin moving to the surface.

In addition, in the content ratio of the two resins, it is preferable that the base material separated into the surface and the resin having excellent adhesiveness are 10% by weight or more and 30% by weight or less relative to the total weight of the resin forming the bulk that does not move to the surface. If it is less than 10% by weight, the change in surface properties is not large, and if it is more than 30% by weight, it affects the bulk properties, and there is a problem that the heat resistance or long-term reliability of the material is deteriorated.

In order to enable the surface separation between resins to be realized on both sides of the material, it is preferable that the surface energy of the support to be coated is 15 mJ/m ² or less for drying the resin combination. The surface not in contact with this support is exposed to air (0 mJ/m ² ) to provide a driving force that allows the resin of low surface energy to move, but in order to induce surface separation from the surface in contact with the support, the low surface as described above It is important to construct the energy support surface. Otherwise, it does not have sufficient driving force to induce the surface separation phenomenon. Generally, a release film containing a fluorine component or a support having a low surface energy surface forming a structure such as the lotus leaf effect may be used.

As a heat transfer adhesive material, it is possible to use general heat transfer fillers in addition to minimizing contact resistance through the resin structure as described above and additionally related to heat transfer characteristics required.

Heat transfer additives or fillers include iron, aluminum, nickel, silver, gold, aluminum nitride, zinc oxide, boron nitride, silicon carbide, silicon nitride oxide, silicon oxide (silica), aluminum hydroxide, magnesium oxide, diamond, carbon fiber, carbon nano At least one selected from tubes, graphene, and the like can be used.

In addition, other components include a curing agent for curing the polymer resin, a dispersant for additives, a surfactant, and an antifoaming agent.

In addition, the method of manufacturing a high-efficiency heat dissipation adhesive material according to the present invention uses a resin having excellent adhesion to the substrate and a resin that forms a bulk, but the resin having excellent adhesion to the substrate is spontaneously dried during coating and drying of the material. It characterized in that to separate toward both surfaces of the resin forming the bulk. That is, the heterogeneous resins are not uniformly mixed, but the resin having excellent adhesion to the substrate is spontaneously separated to both surfaces during the drying process after coating of the material to form surface properties to minimize contact resistance with the substrate, and other The resin having excellent heat resistance forms bulk characteristics in the middle to maintain excellent reliability.

The essential configuration related to the manufacturing method of the high-efficiency heat dissipation adhesive material will be referred to the above.

In this specification, only a few examples of various embodiments performed by the present inventors are described, but the technical spirit of the present invention is not limited to or limited thereto, and can be variously implemented by a person skilled in the art.

A1: Resin with excellent adhesion to the surface
A2: Polymer resin having excellent heat-resistant reliability to form bulk

Claims (12)

In the heat dissipation adhesive material,
It includes a heterogeneous resin composed of a non-polar resin and a polar resin,
The non-polar resin has a weight average molecular weight of 3,000 to 10,000, a surface energy of 25 mJ/m ² or less,
The polar resin has a weight average molecular weight of 50,000 to 1,000,000, a surface energy of 35 mJ/m ² or more,
The non-polar resin is separated by spontaneously moving toward the surface during the drying process after coating, the polar resin is characterized in that to form a bulk, heat-resistant adhesive material. delete According to claim 1,
The non-polar resin is at least one selected from acrylic resins or silicone resins, and the polar resin is at least one selected from epoxy resins, phenoxy resins, polyimide resins, and polyamideimide resins. delete delete delete According to claim 1,
The non-polar resin is 10% by weight or more and 30% by weight or less based on the weight of the polar resin, and the difference in surface energy of the heterogeneous resin is 10 mJ/m ² or more, and a heat dissipation adhesive material. According to any one of claims 1, 3, and 7,
The surface energy of the support used for drying by coating the non-polar resin and the mixed resin of the polar resin is 15 mJ/m ² or less. Non-polar and polar resins of different kinds of resins are used,
The non-polar resin has a weight average molecular weight of 3,000 to 10,000, a surface energy of 25 mJ/m ² or less,
The polar resin has a weight average molecular weight of 50,000 to 1,000,000, a surface energy of 35 mJ/m ² or more,
The non-polar resin is spontaneously separated to both surfaces of the polar resin during the drying process after coating of the material, and the polar resin is formed to form a bulk, so that a heat-resistant adhesive material is produced. The method of claim 9,
The non-polar resin is at least one selected from acrylic resins or silicone resins, and the polar resin is at least one selected from epoxy resins, phenoxy resins, polyimide resins, and polyamideimide resins. . The method of claim 9,
The non-polar resin is to reduce the contact resistance with the substrate, the polar resin is characterized in that it has a heat resistance by forming a bulk characteristic in the middle of the material, the method of manufacturing a heat-resistant adhesive material. The method according to any one of claims 9 to 11,
A method of manufacturing a heat dissipation adhesive material, wherein a support is used to coat and dry the mixed resin of the non-polar resin and the polar resin, but the surface energy of the support is 15 mJ/m ² or less.

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