KR102644757B1 - Heat spread heat - Google Patents

Abstract

A heat dissipation sheet according to an embodiment of the present invention includes a graphite sheet; and a metal layer disposed on the graphite sheet, wherein the metal layer is disposed in contact with the graphite sheet, the average opening ratio of the surface of the metal layer is 1% or less, and the maximum height roughness of the interface between the graphite sheet and the metal layer (Ry The ratio (Ra _m /Ry _i ) of the center line average roughness (Ra _{m )} of the outer surface of the metal layer to i) may be 0.05 or more.

Description

Heat dissipation sheet {Heat spread heat}

The present invention relates to a heat dissipation sheet. This invention was derived from research conducted as part of the Ministry of SMEs and Startups' development of technology for commercializing large-area heat dissipation sheets for 65-inch QD-OLED TVs (Project identification number: 1711122878, project period: 2021.11.01 ~ 2022.10.31).

Recently, as electrical and electronic devices have become more high-performance, lighter, thinner, and smaller, the demand for heat dissipation sheets that can effectively dissipate heat generated from heat sources such as semiconductor components and light-emitting components embedded in them has been steadily increasing.

Common heat dissipation sheets used were copper sheets, copper/graphite laminates, and graphite sheets. Among these, copper sheets have the advantage of having both heat dissipation properties and electromagnetic wave shielding properties, but as the thickness increases, they lack flexibility and have high density, which limits weight reduction. In addition, graphite sheets have the advantage of having high thermal conductivity and light weight, but have the disadvantage of requiring the addition of a separate sheet for electromagnetic wave shielding.

A copper/graphite laminate was proposed to solve this problem. However, copper sheets and graphite sheets have significantly different surface properties, so they must be attached using a separate adhesive, but there is a problem in that the overall heat conduction efficiency is reduced due to the low thermal conductivity of the polymer that makes up the adhesive. Additionally, there is a problem in that it is difficult to implement a thin heat dissipation sheet due to the thickness of the adhesive layer.

One of the several purposes of the present invention is to provide a heat dissipation sheet with improved thermal conductivity.

One of the many purposes of the present invention is to provide a heat dissipation sheet that is thin and has excellent mechanical durability.

One of the many purposes of the present invention is to provide a heat dissipation sheet that has a dust prevention function without a separate sealing part.

A heat dissipation sheet according to an embodiment of the present invention includes a graphite sheet; and a metal layer disposed on the graphite sheet, wherein the metal layer is disposed in contact with the graphite sheet, the average opening ratio of the surface of the metal layer is 1% or less, and the maximum height roughness of the interface between the graphite sheet and the metal layer (Ry The ratio (Ra _m /Ry _i ) of the center line average roughness (Ra _{m )} of the outer surface of the metal layer to i) may be 0.05 or more.

At this time, the thermal conductivity of the heat dissipation sheet including the graphite sheet and the metal layer in the thickness direction may be 5 W/m·K or more.

Meanwhile, an organic layer may not be disposed between the graphite sheet and the metal layer.

In one example of the present invention, the center line average roughness (Ra) of the metal layer may be 1 μm or less.

Additionally, the maximum height roughness (Ry) of the metal layer may be 5 μm or less.

Additionally, the average thickness of the metal layer may be in the range of 10 nm or more and/or 30.0 μm or less.

Additionally, the peeling strength of the metal layer may be higher than the breaking strength of the graphite sheet.

Additionally, the metal layer may include one or more selected from the group consisting of copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), and tungsten (W).

Additionally, the metal layer may be a vapor deposition layer.

Meanwhile, the average thickness of the graphite sheet may be 10 μm or more and/or 1000 μm or less.

Additionally, the graphite sheet may include one or more selected from the group consisting of natural graphite, artificial graphite, expanded graphite, graphene, Kish graphite, and carbon nanotubes (CNTs).

Additionally, the graphite sheet may include a needle-shaped and/or plate-shaped structure.

Meanwhile, the heat dissipation sheet according to the present invention may further include a metal layer disposed on the other side of the graphite sheet on one side of which the metal layer is disposed.

At this time, the graphite sheet may be placed in direct contact with the two metal layers.

One of the many effects of the present invention is that it can provide a heat dissipation sheet that has both excellent thermal conductivity and electromagnetic wave shielding functions.

One of the many effects of the present invention is that the mechanical strength of the heat dissipation sheet can be improved.

One of the many effects of the present invention is to reduce the thickness of the heat dissipation sheet.

However, the various and beneficial advantages and effects of the present invention are not limited to the above-described content, and may be more easily understood in the process of explaining specific embodiments of the present invention.

1 is a cross-sectional view schematically showing an electromagnetic wave shielding and heat dissipation composite sheet according to the present invention.
Figure 2 is an SEM image taken of the interface after FIB (Focused Ion Beam) milling of the electromagnetic wave shielding and heat dissipation composite sheet manufactured in an example of the present invention, and Figure 3 is an enlarged view of Figure 2.
Figure 4 is an image taken of an electromagnetic wave shielding and heat dissipation composite sheet manufactured in an example of the present invention.
Figure 5 is an image taken of the surface after a peel test of the electromagnetic wave shielding and heat dissipation composite sheet manufactured in an example of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and attached drawings. This is not intended to limit the technology described herein to specific embodiments, but should be understood to include various modifications, equivalents, and/or alternatives to the embodiments of the present invention. In connection with the description of the drawings, similar reference numbers may be used for similar components.

In order to clearly explain the present invention in the drawings, parts that are not relevant to the description are omitted, and the thickness is enlarged to clearly express various layers and regions. Components with the same function within the scope of the same idea are referred to by the same reference. It can be explained using symbols.

In this specification, expressions such as “have,” “may have,” “includes,” or “may include” refer to the presence of the corresponding feature (e.g., a numerical value, function, operation, or component such as a part). , and does not rule out the existence of additional features.

As used herein, expressions such as “A or B,” “at least one of A or/and B,” or “one or more of A or/and B” may include all possible combinations of the items listed together. . For example, “A or B”, “at least one of A and B”, or “at least one of A or B” (1) includes at least one A, (2) includes at least one B, or (3) it may refer to all cases including both at least one A and at least one B.

In the drawing, the

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the embodiments described herein.

The present invention relates to a heat dissipation sheet. 1 is a cross-sectional view schematically showing a heat dissipation sheet according to the present invention. Referring to Figure 1, a heat dissipation sheet 1 according to an embodiment of the present invention includes a graphite sheet 10; and a metal layer 20 disposed on the graphite sheet 10.

At this time, the metal layer 20 may be disposed in contact with the graphite sheet 10. The fact that the metal layer 20 is disposed in contact with the graphite sheet 10 may mean that an interface formed by the metal layer 20 and the graphite sheet 10 exists, and the heat dissipation sheet according to the present invention ( This may mean that the metal layer 20 of 1) has a structure attached to the graphite sheet 10. The overall thickness of the heat dissipation sheet according to the present invention can be reduced by arranging the metal layer and the graphite sheet to contact each other as described above.

A conventional laminated heat dissipation sheet including a graphite sheet and a copper foil used an adhesive to bond the graphite sheet and the copper foil. Since both graphite sheets and copper foils do not have surface adhesion, the plan was to manufacture a heat dissipation sheet in the form of a single sheet, but the adhesive caused various problems. First, polymers, which are the main component of adhesives, have very low thermal conductivity. To compensate for this, heat dissipation fillers, etc., mixed with adhesives are sometimes used, but problems arise such as increased product cost and weight. In addition, curable adhesives have the problem of greatly reducing flexibility after curing, and when thermoplastic polymers are used, there is a problem of not fixing the copper foil and graphite sheet when heated. The present invention was developed to solve this problem. The heat dissipation sheet according to the present invention can simultaneously improve thermal conductivity and mechanical durability by arranging the metal layer and the graphite sheet in contact with each other, and has the inherent electromagnetic wave shielding function of the metal layer. You can utilize it.

In addition, the opening ratio of the surface of the metal layer of the heat dissipation sheet according to the present invention is 1% or less, and the center line average roughness (Ra _m ) of the outer surface of the metal layer with respect to the maximum height roughness (Ry _i ) of the interface between the graphite sheet and the metal layer. The ratio (Ra _m /Ry _i ) may be 0.05 or more. In this specification, “opening ratio” may mean the ratio of the area exposed by the lower graphite sheet to the area of the metal layer in a certain range, for example, 1/ of the shortest distance from the center of the outer surface area of the metal layer to the end. It may mean a value measured for the area inside a circle with a radius of 2. The ratio of the center line average roughness (Ra _m ) of the outer surface of the metal layer to the maximum height roughness (Ry _i ) of the interface between the graphite sheet and the metal layer (Ra _m /Ry _i ) may be 0.05 or more, 0.055 or more, or 0.06 or more. and may be 0.20 or less, 0.19 or less, or 0.18 or less.

In one example of the present invention, the thermal conductivity of the electromagnetic wave shielding and heat dissipation composite sheet according to the present invention in the thickness direction may be 5 W/m·K or more. Since the electromagnetic wave shielding and heat dissipation composite sheet according to the present invention does not have a separate layer between the metal layer and the graphite layer as described above, the thermal conductivity of the electromagnetic wave shielding and heat dissipation composite sheet can be affected only by the thermal conductivity of the metal layer and the graphite layer. there is. Accordingly, it can have higher thermal conductivity than a conventional heat dissipation sheet. The thermal conductivity of the electromagnetic wave shielding and heat dissipation composite sheet in the thickness direction is, for example, 5.0 W/m·K or more, 6.0 W/m·K or more, 7.0 W/m·K or more, 8.0 W/m·K or more, 9.0 W It may be more than /m·K or more than 10.0 W/m·K, and the upper limit is not particularly limited, but may be, for example, 7000 W/m·K or less.

In one embodiment of the present invention, an organic layer may not be disposed between the graphite sheet and the metal layer of the heat dissipation sheet according to the present invention. The fact that the organic layer is not disposed between the graphite sheet and the metal layer may mean that there is no organic layer having an area of more than a certain area, for example, 100 μm ² or more, inside the heat dissipation sheet according to the present invention. In addition, the fact that an organic layer is not disposed between the graphite sheet and the metal layer may mean that an adhesive layer is not disposed between the graphite sheet and the metal layer of the heat dissipation sheet according to the present invention. The organic layer may be, for example, an adhesive layer, but is not limited thereto. The heat dissipation sheet according to the present invention is arranged so that the graphite sheet and the metal layer are in contact, and has a structure that does not include a separate adhesive layer, so that thermal conductivity can be improved while having a thin thickness.

In an embodiment of the present invention, the center line average roughness (Ra) of the metal layer disposed on the graphite sheet of the heat dissipation sheet according to the present invention may be 1 μm or less. In this specification, the center line average roughness (Ra) may be a value measured on a cut surface passing through the center of the metal layer, or may be a value measured at the outermost end of the metal layer. The center line average roughness (Ra) of the metal layer may be 1.0 μm or less, 0.9 μm or less, 0.8 μm or less, or 0.7 μm or less, and may be 0.1 μm or more, 0.15 μm or more, or 0.2 μm or more.

Meanwhile, the maximum height roughness (Ry) of the metal layer of the heat dissipation sheet according to the present invention may be 5 μm or less. The maximum height roughness (Ry) may be a value measured on a cut surface passing through the center of the metal layer, or may be a value measured at the outermost end of the metal layer. The maximum height roughness (Ry) of the metal layer may be 5.0 μm or less, 4.5 μm or less, 4.0 μm or less, or 3.5 μm or less, and may be 0.5 μm or more, 0.7 μm or more, or 1.0 μm or more, but is not limited thereto.

In one example of the present invention, the average thickness of the metal layer of the electromagnetic wave shielding and heat dissipation composite sheet according to the present invention may be in the range of 10 nm or more and/or 30.0 μm or less. In this specification, the thickness of a layer may be a value measured on a cut surface passing through the center of the layer, or may be a value measured at the outermost end of the layer. Additionally, in this specification, the average thickness of a layer may mean the arithmetic average of values measured at 10 locations at equal intervals for the layer. The average thickness of the metal layer may be 30.0 μm or less, 25.5 μm or less, or 20.0 μm or less, but is not limited thereto. If the average thickness of the metal layer is less than 10 nm, it may not have a sufficient electromagnetic wave shielding function, and if it exceeds 30 μm, the overall weight of the composite sheet increases, making it difficult to apply to thin film devices, and flexibility decreases, causing cracks in the metal layer when bending. It can happen.

In one example, the peeling strength of the metal layer of the heat dissipation sheet according to the present invention may be higher than the breaking strength of the graphite sheet. The fact that the peeling strength of the metal layer is higher than the breaking strength of the graphite sheet means that the graphite sheet, which is an adherend, is destroyed before the metal layer is peeled off when mechanical force is applied to separate the metal layer from the graphite sheet. can do. In other words, this may mean that the metal layer has a peeling strength greater than the value at which destruction of the adherend occurs in a peeling test for the metal layer. Destruction of the graphite sheet may mean, for example, that when the metal layer is peeled off, more than 30% of the area of the graphite sheet bonded to the metal layer is destroyed. For example, the peel strength of the metal layer may be tested by a method conforming to ASTM D3330, and the peel strength may be measured at a 90° angle. While the conventional heat dissipation sheet that combines a graphite sheet and a metal foil using an adhesive has a peeling strength determined based on the adhesive strength of the adhesive layer, the heat dissipation sheet according to the present invention forms a metal layer directly on the graphite sheet, providing high mechanical strength even without an adhesive layer. It can have strength.

The composition of the metal of the metal layer of the heat dissipation sheet according to the present invention is not particularly limited as long as it satisfies the above-mentioned thermal conductivity. The metal may include, for example, one or more selected from the group consisting of copper (Cu), gold (Au), silver (Ag), aluminum (Al), and tungsten (W).

Meanwhile, the metal layer of the heat dissipation sheet according to the present invention may be a vapor deposition layer. The metal layer can be formed by directly depositing the above-described metal component on a graphite sheet. That is, the metal layer may be a deposition layer. The method of depositing the metal layer is not particularly limited as long as it satisfies the characteristics of the metal layer described above. For example, physical vapor deposition (PVD) or chemical vapor deposition (CVD) can be used. .

In one embodiment of the present invention, the average thickness of the graphite layer of the electromagnetic wave shielding and heat dissipation composite sheet according to the present invention may be 10 μm or more and/or 1000 μm or less. The average thickness of the graphite layer may be a value measured in the same manner as the average thickness of the metal layer described above. If the average thickness of the graphite layer is less than 10 μm, the desired level of heat dissipation performance may not be achieved, and if it exceeds 1000 μm, application to thin film displays, etc. may be difficult.

The type of the graphite sheet is not particularly limited as long as it has a sufficient heat dissipation function. For example, the graphite sheet may include one or more selected from the group consisting of natural graphite, artificial graphite, expanded graphite, graphene, Kish graphite, and carbon nanotubes (CNTs).

In one example, the graphite sheet of the heat dissipation sheet according to the present invention may include a needle-shaped and/or plate-shaped structure. The needle-shaped and/or plate-shaped structure may be a structure included inside the graphite sheet, and may mean a shape visible to the naked eye when observed with a microscope or the like.

In one embodiment of the present invention, the heat dissipation sheet according to the present invention may further include a metal layer disposed on the other side of the graphite sheet on one side of which the metal layer is disposed. The additionally disposed metal layer may be disposed on a different side from the metal layer disposed on the graphite sheet, or may be disposed on one side of the graphite sheet on which the metal layer is not disposed. That is, the heat dissipation sheet according to this embodiment may have metal layers disposed on both sides of the graphite sheet in the thickness direction.

Conventional heat dissipation sheets using graphite sheets had a problem with dust generated from the graphite sheets. Such dust is generated during the process of performing punching or lamination work, or due to vibration applied to an object including a heat dissipation sheet, and can cause a decrease in the quality of the final product. In the past, a separate sealing member was used to prevent this, but this, like the adhesive layer, had the problem of lowering thermal conductivity. On the other hand, since the heat dissipation sheet according to the present invention forms a metal layer directly on the graphite sheet, dust can be prevented without a separate sealing member and can have excellent thermal conductivity.

In this embodiment, the graphite sheet may be placed in direct contact with the two metal layers. That is, a separate adhesive layer may not be disposed between the metal layer disposed on both sides in the thickness direction of the graphite sheet and the graphite sheet. In this case, the heat dissipation sheet according to the present invention includes a metal layer; graphite sheet; and may have a structure in which metal layers are sequentially stacked, the metal layers; graphite sheet; And it may be a structure in which the metal layer is disposed in direct contact.

Hereinafter, the present invention will be described in more detail through the following examples. However, the spirit of the present invention is not limited to the embodiments described later.

<Example 1>

A graphite sheet (SS260-082, manufactured by Neograph) with a thickness of 0.82 mm was prepared in a size of 150 mm x 100 mm, and a metal layer was formed with aluminum (Al) on the surface of the sheet. The metal layer was formed by sputtering aluminum on a graphite sheet prepared at a pressure of 2.5 × 10 ^-3 Torr using 100 sccm of argon (Ar) as a carrier.

Figure 4 is an image taken of an example heat dissipation sheet in which an aluminum layer was formed on a graphite sheet. Referring to Figure 4, it can be seen that the aluminum layer is evenly deposited and disposed on the graphite sheet.

Examples 2 to 4

A metal layer was formed using aluminum in the same manner as in Example 1, except that the thickness of the metal layer formed was varied by adjusting the deposition time conditions during the sputtering process.

Figure 2 is an SEM image of the boundary surface of the heat dissipation sheet manufactured in Example 1 after FIB (Focused Ion Beam) milling to a size of 10 μm x 10 μm, and Figure 3 is an enlarged view of Figure 2. Referring to Figures 2 and 3, it can be seen that the graphite layer 10 and the metal layer 20 are disposed in contact with each other. Additionally, it can be confirmed that no other organic layer is included between the graphite layer 10 and the metal layer 20.

Table 1 below shows the center line average roughness (Ra) and maximum height roughness (Ry) of the metal layer of the heat dissipation sheet manufactured in Examples 1 to 4, and the center line average roughness (Ra) and maximum height roughness (Ry) of the outer surface of the graphite layer. The measurement results are described.

measuring position Example 1
(0.5μm) Example 2
(1.0μm) Example 3
(3.0μm) Example 4
(5.0μm) Graphite sheet① Ra [μm] One 0.367 0.321 0.320 0.263 0.511 2 0.300 0.250 0.307 0.349 0.673 3 0.459 0.367 0.200 0.283 0.526 4 0.285 0.313 0.246 0.263 0.575 Ry [μm] One 2.231 2.114 2.102 1.554 2.835 2 2.110 1.513 1.945 1.99 3.391 3 2.720 2.157 1.290 1.939 3.008 4 1.524 2.278 1.642 1.642 3.392 Ra _m /Ry _i One 0.129 0.113 0.113 0.093 0.180 2 0.088 0.074 0.091 0.103 0.198 3 0.153 0.122 0.066 0.094 0.175 4 0.084 0.092 0.073 0.078 0.170 average 0.114 0.100 0.086 0.092 0.181

Referring to Table 1, it can be seen that the center line average roughness (Ra _m ) of the metal layer relative to the maximum height roughness (Ry _i ) of the outer surface of the graphite sheet has a value of 0.05 or more.

<Experimental Example 1>

A peel strength test was performed on the heat dissipation sheet manufactured in Example 1. The peel strength test was performed by fixing the sample to a metal plate and peeling it off by applying force to the metal layer at a 90° angle according to test method F of ASTM D3330, and whether the interface was destroyed after peeling was observed through an optical microscope.

Figure 5 is an image taken of the surface after a peel strength test was performed on a heat dissipation sheet with a metal layer formed directly on the surface of a graphite sheet. In Figure 5, area A is an area where the graphite sheet is destroyed. Looking at area A of FIG. 5, it can be seen that the surface of the graphite sheet after peeling off the deposited metal layer has an irregularly raised shape. When observing a graphite sheet with a surface roughness of several μm or less with the naked eye, the surface appears smooth, but the irregularly shaped raised structure shown above is a phenomenon that occurs when the surface of the graphite sheet is destroyed during the process of peeling off the metal layer. . In the case of area A where force is applied for the peeling test, the interface between the metal layer and the graphite sheet is not peeled off, but a part of the graphite sheet is broken while attached to the metal layer, resulting in peeling of the metal layer of the heat dissipation sheet according to the present invention. It can be confirmed that the strength is higher than the breaking strength of the graphite layer.

<Example 5>

A metal layer was formed using aluminum in the same manner as in Example 1, except that a graphite sheet (QBC 0.82T, manufactured by Banghai) with a thickness of 0.82 mm was used.

Examples 6 to 8

A metal layer was formed using aluminum in the same manner as in Example 5, except that the thickness of the metal layer formed was changed by adjusting the deposition time conditions during the sputtering process.

Table 2 below shows the center line average roughness (Ra) and maximum height roughness (Ry) of the metal layer of the heat dissipation sheet manufactured in Examples 5 to 8, and the center line average roughness (Ra) and maximum height roughness (Ry) of the outer surface of the graphite layer. The measurement results are described.

measuring position Example 5
(0.5μm) Example 6
(1.0μm) Example 7
(3.0μm) Example 8
(5.0μm) Graphite sheet② Ra [μm] One 0.278 0.314 0.23 0.283 0.437 2 0.256 0.332 0.171 0.328 0.362 3 0.272 0.302 0.198 0.247 0.442 4 0.276 0.314 0.278 0.26 0.409 Ry [μm] One 1.567 1.951 1.637 2.05 2.361 2 1.496 2.333 1.067 2.102 2.255 3 1.484 1.942 1.409 1.615 2.676 4 1.891 1.907 1.458 1.704 2.295 Ra _m /Ry _i One 0.118 0.133 0.097 0.120 0.185 2 0.114 0.147 0.076 0.145 0.161 3 0.102 0.113 0.074 0.092 0.165 4 0.120 0.137 0.121 0.113 0.178 average 0.113 0.132 0.092 0.118 0.172

<Example 9>

A metal layer was formed using aluminum in the same manner as in Example 1, except that a graphite sheet (TG771, manufactured by Neograph) with a thickness of 0.20 mm was used.

Examples 10 to 12

A metal layer was formed using aluminum in the same manner as in Example 9, except that the thickness of the metal layer formed was changed by adjusting the deposition time conditions during the sputtering process.

Table 3 below shows the center line average roughness (Ra) and maximum height roughness (Ry) of the metal layer of the heat dissipation sheet manufactured in Examples 9 to 12, and the center line average roughness (Ra) and maximum height roughness (Ry) of the outer surface of the graphite layer. The measurement results are described.

measuring position Example 5
(0.5μm) Example 6
(1.0μm) Example 7
(3.0μm) Example 8
(5.0μm) Graphite sheet② Ra [μm] One 0.299 0.251 0.194 0.362 0.466 2 0.272 0.303 0.39 0.31 0.328 3 0.335 0.218 0.203 0.257 0.413 4 0.302 0.224 0.343 0.204 0.399 Ry [μm] One 2.379 1.348 0.936 1.94 2.665 2 1.776 1.834 2.419 1.684 1.84 3 2.379 1.569 1.327 1.436 2.374 4 1.792 1.317 2.512 1.229 2.422 Ra _m /Ry _i One 0.105 0.089 0.068 0.128 0.164 2 0.080 0.089 0.115 0.091 0.097 3 0.111 0.072 0.067 0.085 0.137 4 0.089 0.066 0.101 0.060 0.118 average 0.097 0.079 0.088 0.091 0.129

<Example 13>

A metal layer was formed using aluminum in the same manner as in Example 1, except that a graphite sheet (DSN5032, manufactured by DASEN) with a thickness of 0.032 mm was used.

Examples 14 to 16

A metal layer was formed using aluminum in the same manner as in Example 13, except that the thickness of the metal layer formed was changed by adjusting the deposition time conditions during the sputtering process.

Table 4 below shows the center line average roughness (Ra) and maximum height roughness (Ry) of the metal layer of the heat dissipation sheet manufactured in Examples 13 to 16, and the center line average roughness (Ra) and maximum height roughness (Ry) of the outer surface of the graphite layer. The measurement results are described.

measuring position Example 13
(0.5μm) Example 14
(1.0μm) Example 15
(3.0μm) Example 16
(5.0μm) Graphite layer④ Ra [μm] One 0.388 0.382 0.172 0.529 0.268 2 0.349 0.502 0.195 0.279 0.342 3 0.265 0.294 0.300 0.425 0.505 4 0.323 0.491 0.282 0.439 0.581 Ry [μm] One 2.509 2.017 1.100 3.354 1.617 2 1.904 2.811 1.327 1.854 1.880 3 1.834 1.659 1.938 2.198 2.687 4 2.083 2.907 1.491 2.729 2.931 Ra _m /Ry _i One 0.095 0.137 0.135 0.061 0.187 2 0.101 0.103 0.148 0.058 0.082 3 0.168 0.088 0.098 0.100 0.141 4 0.171 0.095 0.145 0.083 0.129 average 0.106 0.131 0.075 0.135 0.134

Although the embodiments of the present invention have been described in detail above, the present invention is not limited by the above-described embodiments and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various forms of substitution, modification, and change may be made by those skilled in the art without departing from the technical spirit of the present invention as set forth in the claims, and this also falls within the scope of the present invention. something to do.

1: Heat dissipation sheet
10: Graphite sheet
20: metal layer

Claims (14)

graphite sheet; and
It includes a metal layer disposed on the graphite sheet,
The metal layer is disposed in contact with the graphite sheet,
The average opening ratio of the surface of the metal layer is 1% or less,
A heat dissipation sheet wherein the ratio (Ra _m /Ry _i ) of the center line average roughness (Ra _m ) of the outer surface of the metal layer to the maximum height roughness (Ry _i ) of the interface between the graphite sheet and the metal layer is 0.05 or more.
According to paragraph 1,
A heat dissipation sheet wherein the composite sheet including the graphite sheet and the metal layer has a thermal conductivity in the thickness direction of 5 W/m·K or more.
According to paragraph 1,
A heat dissipation sheet in which an organic layer is not disposed between the graphite sheet and the metal layer.
According to paragraph 1,
A heat dissipation sheet wherein the center line average roughness (Ra) of the metal layer is 1 μm or less.
According to paragraph 1,
A heat dissipation sheet wherein the maximum height roughness (Ry) of the metal layer is 5 μm or less.
According to paragraph 1,
A heat dissipation sheet wherein the average thickness of the metal layer is in the range of 10 nm or more and/or 30.0 μm or less.
According to paragraph 1,
A heat dissipation sheet in which the peeling strength of the metal layer is higher than the breaking strength of the graphite sheet.
According to paragraph 1,
The metal layer is a heat dissipation sheet including one or more selected from the group consisting of copper (Cu), gold (Au), silver (Ag), aluminum (Al), and tungsten (W).
According to paragraph 1,
A heat dissipation sheet in which the metal layer is a deposition layer.
According to paragraph 1,
A heat dissipation sheet wherein the average thickness of the graphite sheet is 10 μm or more and/or 1000 μm or less.
According to paragraph 1,
The graphite sheet is a heat dissipation sheet containing at least one selected from the group consisting of natural graphite, artificial graphite, expanded graphite, graphene, Kish graphite, and carbon nanotubes (CNTs).
According to paragraph 1,
The graphite sheet is a heat dissipation sheet including a needle-shaped and/or plate-shaped structure.
According to paragraph 1,
A heat dissipation sheet further comprising a metal layer disposed on the other side of the graphite sheet on which the metal layer is disposed on one side.
According to clause 13,
The graphite sheet is a heat dissipation sheet disposed in direct contact with the two metal layers.