Heat dissipation member

Abstract

The present invention relates to a heat dissipation member, which has excellent thermal conductivity and has a coefficient of thermal expansion that can be variously adjusted. The heat dissipation member according to the present invention comprises a diamond layer, which is formed by chemical vapor deposition (CVD) and has a thickness of 100 μm or more, and a cover layer, which is formed on at least one surface of the diamond layer, wherein the surface roughness (Ra) of the diamond layer on which the cover layer is formed is 0.05-5 μm.

Description

heat dissipation member

[0001] The present invention relates to a heat dissipation member having excellent thermal conductivity and a thermal expansion coefficient that can be adjusted in various ways.

[0002]

[0003] As electronic devices become more powerful, the heat generated by their components, such as semiconductors and lasers, during operation is steadily increasing. Failure to adequately dissipate this increased heat can lead to reduced reliability and performance of the electronic components.

[0004] Accordingly, high-power electronic devices require heat sinks capable of rapidly dissipating the large amounts of heat generated. These heat sinks must possess excellent thermal conductivity for rapid heat dissipation, as well as high performance to prevent delamination and deformation caused by differences in thermal expansion coefficients at the interface with the electronic device.

[0005]

[0006] The task of the present invention is to provide a thermal conductivity of 600 W / mK or more and a thermal conductivity of 2 to 10×10 -6 The purpose is to provide a heat dissipating member that can be applied to various electronic devices because the thermal expansion coefficient can be adjusted within the range of / K.

[0007] However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0008]

[0009] To solve the above problem, the present invention provides a heat dissipation member according to the following (1) to (12).

[0010] (1) A heat dissipation member comprising a diamond layer having a thickness of 100 ㎛ or more formed by a CVD (Chemical Vapor Depositon) method and a cover layer formed on at least one surface of the diamond layer, wherein the surface roughness (Ra) of the diamond layer on which the cover layer is formed is 0.05 to 5 ㎛.

[0011] (2) A heat dissipation member in (1), wherein a bonding layer having a thermal expansion coefficient greater than the thermal expansion coefficient of the diamond layer and smaller than the thermal expansion coefficient of the cover layer is additionally formed between the diamond layer and the cover layer.

[0012] (3) In (2), a heat dissipation member comprising at least one metal selected from titanium (Ti), tungsten (W), silicon (Si), chromium (Cr), and nickel (Ni) and / or a carbide thereof.

[0013] (4) A heat dissipation member in any one of (1) to (3), wherein the cover layer is made of copper (Cu) or a copper (Cu) alloy.

[0014] (5) A heat dissipation member in any one of (1) to (4), wherein the surface roughness (Ra) of the diamond layer on which the cover layer is formed is 0.5 to 3.5 ㎛.

[0015] (6) A heat dissipation member in which the surface of the diamond layer on which the cover layer is formed is polished and then the diamond is regrown so that the surface has a facet structure composed of (100), (101) and / or (111) crystal planes, in any one of (1) to (5).

[0016] (7) A heat dissipation member in any one of (1) to (6), wherein the diamond layer has a polycrystalline structure, and the average size of diamond grains measured by EBSD on the surface of the diamond layer on which the cover layer is formed is 10 µm or less.

[0017] (8) A heat-radiating member in any one of (1) to (7), wherein the CVD method is a Microwave Plasma Chemical Vapor Depositon (MPCVD) method.

[0018] (9) A heat dissipation member in any one of (1) to (8), wherein a second cover layer made of a composite material is formed on the surface of the diamond layer on the opposite side where the cover layer is formed, and the second cover layer is made of a copper (Cu)-diamond composite material in which diamond particles are dispersed in a copper (Cu) or copper (Cu) alloy matrix.

[0019] (10) In any one of (1) to (9), the thermal conductivity (W / mK) of the heat dissipation member is 600 W / mK or more, and the thermal expansion coefficient at 25°C is 2×10 -6 / K ~ 10×10 -6 / K, heat dissipation member.

[0020] (11) A heat dissipation member having a heat exchange part formed in the shape of a plurality of protrusions on one side of the heat dissipation member described in any one of (1) to (10).

[0021] (12) A heat-radiating member, wherein a pattern of a predetermined shape is formed on the cover layer of the heat-radiating member described in any one of (1) to (10) so that the diamond layer is exposed.

[0022]

[0023] The heat dissipation member according to the present invention has a thermal conductivity of 600 W / mK or more and a thermal conductivity of 2 to 10×10 -6 / K, it can be used as a heat sink for various high-power electronic devices.

[0024] In addition, the heat dissipation member according to one embodiment of the present invention has excellent bonding strength between the CVD diamond layer and the cover layer covering it, and cracks do not occur during the process of bonding the CVD diamond layer and the cover layer.

[0025] In addition, the heat dissipation member according to one embodiment of the present invention maintains good bonding strength between the CVD diamond layer and the cover layer covering it even when subjected to repeated thermal shock cycles of low and high temperatures.

[0026] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0027]

[0028] Fig. 1 is a cross-sectional view of a heat dissipation member according to the first embodiment of the present invention.

[0029] Figure 2 shows the change in thermal conductivity (TC) and coefficient of thermal expansion (CTE) according to the thickness of the copper (Cu) layer, which is the cover layer of the heat dissipation member according to the first embodiment of the present invention.

[0030] FIG. 3 shows the bonding strength between the cover layer and the diamond layer and the presence or absence of cracks generated when bonding the cover layer and the diamond layer according to the surface roughness (Ra) of the diamond layer in the heat dissipation member according to the first embodiment of the present invention.

[0031] Figure 4 shows the state of the surface of the diamond layer to which the cover layer is bonded.

[0032] Figure 5 shows the results of surface roughness analysis of a diamond surface formed with a predetermined thickness, a diamond surface that has been wrapped, and a diamond that has been regrown after wrapping.

[0033] Figure 6 is an EBSD analysis image of a diamond surface formed with a film of a predetermined thickness, a diamond surface that has been wrapped, and a diamond surface that has been regrown after wrapping.

[0034] Figure 7 shows the results of analyzing the grain size distribution and average grain size of a diamond surface formed with a predetermined thickness as in Figure 6 and a diamond surface regrown after lapping.

[0035] FIG. 8 is a cross-sectional view of a heat dissipation member in which a bonding layer is formed between a diamond layer and a cover layer according to a second embodiment of the present invention.

[0036] Figure 9 shows a cross-sectional image (left) of a heat dissipation member manufactured according to the second embodiment after the SPS process and the EDS mapping result (right) thereof.

[0037] Figure 10 shows a cross-sectional image (left) of the heat dissipation member of Figure 9 after applying 100 cooling-heating thermal shocks between low temperature (-20°C) and high temperature (350°C) and the EDS mapping result (right).

[0038] Fig. 11 is a cross-sectional view of a heat dissipation member in which a bonding layer is formed between a diamond layer and a cover layer according to a third embodiment of the present invention.

[0039] Fig. 12 is a cross-sectional view of a heat dissipation member according to the fourth embodiment of the present invention.

[0040] Fig. 13 is a cross-sectional view of a heat dissipation member according to the fifth embodiment of the present invention.

[0041] Fig. 14 is a cross-sectional view of a heat dissipation member according to the sixth embodiment of the present invention.

[0042] Fig. 15 is a cross-sectional view of a heat dissipation member according to the seventh embodiment of the present invention.

[0043] Fig. 16 is a cross-sectional view of a heat dissipation member according to the eighth embodiment of the present invention.

[0044] Fig. 17 is a cross-sectional view of a heat dissipation member according to the ninth embodiment of the present invention.

[0045] Fig. 18 is a cross-sectional view of a heat dissipation member according to the 10th embodiment of the present invention.

[0046]

[0047] Below, with reference to the attached drawings, embodiments of the present invention are described in detail to facilitate implementation by those skilled in the art. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0048] In addition, in order to clearly explain the invention in the drawings, parts unrelated to the explanation were omitted, and similar parts were given similar drawing symbols throughout the specification.

[0049] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0050] The terms "about," "substantially," and the like used in this specification are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which exact or absolute values ​​are mentioned to aid understanding of the present application.

[0051] Throughout this specification, the term "a combination of these" in a Markushi format expression means a mixture or combination of one or more selected from the group consisting of the components described in the Markushi format expression, and means including one or more selected from the group consisting of said components. Throughout this specification, the description of "A and / or B" means "A or B, or, A and B."

[0052]

[0053] [First Embodiment]

[0054] As illustrated in FIG. 1, the heat dissipation member according to the first embodiment of the present invention has a cover layer formed on the upper and lower surfaces of a diamond layer, and the roughness of the surface of the diamond layer on which the cover layer is formed is adjusted to a predetermined range.

[0055] In Fig. 1, a cover layer is formed on the upper and lower surfaces of the diamond layer, but the cover layer can be formed in various forms, such as being formed on only one surface of the diamond layer or being formed on all surfaces (upper, lower, and side surfaces) to completely surround the diamond layer.

[0056] The above diamond layer can be formed by depositing a film of a predetermined thickness on a substrate, such as a silicon substrate, using a known CVD (Chemical Vapor Deposition) method and then separating the film from the substrate. The diamond layer formed in this manner can have a polycrystalline structure in the shape of a plate with a flat upper and lower surface. The diamond layer formed by integrally depositing a film using the CVD method has excellent thermal conductivity and a very low coefficient of thermal expansion.

[0057] If the thickness of the diamond layer is less than 100 ㎛, it cannot be applied as a self-supporting substrate due to breakage or warping, and thus the next process cannot be performed. Therefore, the thickness may be 100 ㎛ or more, preferably 200 ㎛ or more, and more preferably 300 ㎛ or more. The diamond layer thickness may be formed up to the maximum thickness that can be obtained by forming a film using the CVD method.

[0058] As the CVD method for forming the above diamond layer, various methods such as hot filament CVD (HFCVD), microwave plasma CVD (hereinafter referred to as 'MPCVD'), direct current plasma jet CVD (DC Plasma Jet CVD), radio frequency plasma CVD (RF Plasma CVD), combustion flame CVD, and electron resonance plasma CVD can be used, and the MPCVD method can be preferably used. This is because the MPCVD method is advantageous in producing a high-quality diamond thin film by using microwave energy to ionize a reaction gas into a plasma state, and the activated gas molecules are deposited on the substrate surface to form a thin film.

[0059] The above cover layer may preferably be made of a metal, and may be made of, for example, an element selected from copper (Cu), silver (Ag), aluminum (Al), magnesium (Mg), and molybdenum (Mo), or an alloy thereof. The term “alloys thereof” refers to a copper (Cu) alloy, a silver (Ag) alloy, an aluminum (Al) alloy, a magnesium (Mg) alloy, and a molybdenum (Mo) alloy, and each alloy may contain 70 wt% or more, 80 wt% or more, 90 wt% or more, or 95 wt% or more of the main element copper (Cu), silver (Ag), aluminum (Al), magnesium (Mg), or molybdenum (Mo), and at this time, the alloy element may contain 1 to 30 wt%. The alloy component may include at least one known element capable of being alloyed with the main element, and preferably includes an alloy element that does not significantly lower thermal conductivity. The above cover layer may preferably be copper (Cu) or a copper (Cu) alloy.

[0060] The above cover layer is a layer that covers the diamond layer and comes into contact with the electronic device to be heat-radiated. Depending on the material used in the cover layer and its thickness, the thermal expansion coefficient and thermal conductivity of the heat-radiating member change.

[0061] Referring to Figure 2, as the thickness of the copper (Cu) layer formed on the upper and lower surfaces of the 500 ㎛ thick polycrystalline diamond layer increases, the thermal conductivity (TC) z (thickness direction), TC xy (plane direction)) decreases and the coefficient of thermal expansion (CTE) increases. This enables the design of thermal conductivity characteristics tailored to the coefficient of thermal expansion of the contact surface of the electronic device being used. For example, if the coefficient of thermal expansion of the electronic device is 4×10 -6 / K and the required thermal conductivity is 1000 W / mK or more, the thickness of the copper (Cu) layer indicated by the red dotted arrow in Fig. 2 can be formed to fit the electronic device. Through this, the heat dissipation member according to the present invention can be used for various high-power electronic devices.

[0062] When the above cover layer is made of metal, the thickness of the cover layer is preferably 5 to 500 ㎛. This is because when the thickness of the cover layer is less than 5 ㎛, the rough surface of the CVD diamond is maintained, making it impossible to perform a semiconductor chip bonding process, etc., and when it exceeds 500 ㎛, the thermal expansion coefficient becomes excessively large and the thermal conductivity becomes low.

[0063] As the thickness of the diamond layer formed using the CVD method increases, the surface roughness (Ra) of the opposite side not in contact with the substrate (i.e., the diamond growth surface) increases. As surface roughness increases, the bonding strength between the diamond layer and the cover layer (e.g., a copper (Cu) layer) formed on that surface increases. Therefore, maintaining a high surface roughness is desirable to enhance the bonding strength between the diamond layer and the cover layer.

[0064] However, the inventors of the present invention discovered that line cracks or micro cracks were generated in the cover layer during the process of bonding the diamond layer and the cover layer formed by the CVD method (e.g., the SPS (Spark Plasma Sintering) process), and analyzed the correlation between the crack generation in the cover layer and the surface roughness of the diamond layer.

[0065] FIG. 3 shows the bonding force (adhesion) between the cover layer and the diamond layer and the presence or absence of cracks generated when bonding the cover layer and the diamond layer according to the surface roughness (Ra) of the diamond layer in the heat dissipation member according to the first embodiment of the present invention.

[0066] As shown in Fig. 3, when the surface roughness (Ra) of the diamond layer is less than 0.05 ㎛, the cover layer is likely to peel off, and when the surface roughness (Ra) exceeds 5 ㎛, cracks are likely to form when bonding the diamond layer and the cover layer. Therefore, it is preferable that the surface roughness (Ra) of the diamond layer be controlled within the range of 0.05 to 5 ㎛, and when considering process stability that prevents cracks from forming during the process while maintaining excellent bonding strength between the diamond layer and the cover layer, it is more preferable that the surface roughness (Ra) of the diamond layer be controlled within the range of 0.5 to 3.5 ㎛.

[0067] Meanwhile, as the thickness of the diamond layer used increases, the surface roughness (Ra) of the surface layer on which the film is formed increases, and when the thickness of the diamond layer is 100㎛ or more, the roughness (Ra) of the surface on which the film is formed can be greater than 5㎛.

[0068] A polishing process was performed to control the surface roughness (Ra) of the deposited diamond layer to less than 5 ㎛. However, even when the surface roughness of the diamond layer was controlled to the range of 0.05 to 5 ㎛ through polishing, the bonding strength between the diamond layer and the cover layer was insufficient, or cracks occurred during the bonding process with the cover layer.

[0069] The reason for this appears to be that when a polycrystalline diamond film is formed on the surface, a facet structure is formed as shown in Fig. 4, and the facet structure is damaged during polishing.

[0070] Therefore, in order to increase the bonding strength between the diamond layer and the cover layer while simultaneously suppressing crack formation in the cover layer, it is desirable to maintain the surface roughness of the diamond layer to which the cover layer is bonded within the range of 0.05 to 5 ㎛ and to form a facet structure on the surface of the diamond layer. Furthermore, it is more desirable to maintain the crystal grain size below a certain level.

[0071] To this end, in the present invention, the surface of a diamond layer having a surface roughness (Ra) exceeding 5㎛ after film formation is polished by a lapping process, and then diamond is regrowthed on the polished surface by a CVD method, so that the surface roughness (Ra) of the diamond layer is 0.05 to 5㎛ while a facet structure is formed on the surface, and the crystal grain size of the polycrystalline structure is small and uniformly distributed.

[0072] Figure 5 shows the results of surface roughness analysis for a diamond surface formed with a film thickness of 500 μm, a diamond surface that was wrapped, and a diamond surface that was regrown after wrapping.

[0073] As shown in Fig. 5, the surface roughness of the diamond formed into a film with a thickness of 500 μm was 6.626 μm, the surface roughness of the diamond that was wrapped was 0.011 μm, and the surface roughness of the diamond that was regrown after wrapping was 1.605 μm.

[0074] As confirmed in Fig. 6, the diamond surface coated with a film thickness of 500 μm and the diamond surface coated with the film and the diamond surface regrown after lapping have a facet structure grown into the (100), (111), and (101) planes, but no facet structure is observed in the lapped diamond surface.

[0075] In addition, the average grain size of the surface of the diamond layer to which the cover layer is bonded is preferably 10 µm or less, and more preferably 5 µm or less.

[0076] Figure 7 shows the results of EBSD analysis of the grain size distribution and average grain size of a diamond surface deposited with a predetermined thickness as in Figure 6 and a diamond surface regrown after lapping. While the average grain size of the diamond surface deposited with a predetermined thickness is 42.52 μm, the average grain size of the diamond surface regrown after lapping is 0.478 μm, showing a significant decrease.

[0077] In this way, when the surface of the diamond layer is polished and then regrown to maintain the surface roughness of the diamond layer within the above range, and the surface of the diamond layer is formed with a facet structure grown in the (100), (111), and (101) planes and a small average grain size, the bonding force between the cover layer and the diamond layer is good, and the occurrence of cracks in the cover layer can be suppressed.

[0078] The heat dissipation member according to the first embodiment can be manufactured through the following process, but the present invention is not necessarily limited thereto.

[0079] A silicon substrate is prepared, cleaned, the oxide film is removed with a hydrofluoric acid (HF) solution, and dried with nitrogen gas. Then, a nanodiamond dispersion is spin-coated onto the silicon substrate to perform diamond seed treatment. After adjusting the CH4 / H2 gas ratio in the range of 1 to 8% on the diamond-seeded substrate, the initial nucleation step and subsequent growth step are controlled to the desired thickness under the conditions of a gas flow rate of 100 to 500 sccm, a pressure of 20 to 100 Torr, a microwave output of 1 to 3 kW, and a substrate temperature of 700 to 900°C, so as to obtain a CVD-diamond sheet of, for example, 500 μm.

[0080] Since the surface roughness (Ra) of the CVD-diamond sheet obtained in this way is very rough, exceeding 10㎛, both sides of the CVD-diamond sheet (the diamond growth surface and the surface in contact with the silicon substrate) are polished through a lapping process so that the surface roughness becomes 0.1㎛ or less.

[0081] By regrowing diamond on both sides of a polished CVD-diamond sheet through an MP-CVD device, the surface roughness (Ra) is made to be in the most desirable range of 1 to 3 ㎛, and a facet structure consisting of (100), (101) and / or (111) crystal planes is formed on the surface.

[0082] After laminating a copper (Cu) plate of a predetermined thickness (e.g., 50 μm) on both sides of the above-mentioned regrown diamond sheet, spark plasma sintering is used to sinter it at about 1000°C, thereby finally manufacturing a heat dissipation member having a laminated structure as shown in Fig. 1.

[0083] In this way, the manufactured heat dissipation member not only had no cracks during the discharge plasma sintering process, as shown in the heat dissipation member in the middle of Fig. 3, but also had good adhesive properties with no peeling of the cover layer.

[0084]

[0085] [Second Embodiment]

[0086] Fig. 8 is a cross-sectional view of a heat dissipation member according to a second embodiment of the present invention. In the second embodiment, the remaining configuration, except for the bonding layer, is the same as in the first embodiment, and therefore, a description thereof is omitted.

[0087] Referring to FIG. 8, the heat dissipation member according to the second embodiment has a single bonding layer formed between the diamond layer and the cover layer.

[0088] The bonding layer is a layer that enhances the bonding strength between the diamond layer and the cover layer, and can be formed with a thickness of 1 nm to 1 μm. If the thickness of the bonding layer is less than 1 nm, its function as a bonding layer is insufficient, and if it exceeds 1 μm, it is undesirable because it affects the thermal conductivity and coefficient of thermal expansion of the entire heat dissipation member.

[0089] The bonding layer may include at least one metal selected from titanium (Ti), tungsten (W), silicon (Si), chromium (Cr), and nickel (Ni) and / or a carbide thereof. In the entire bonding layer, the carbide of at least one metal selected from titanium (Ti), tungsten (W), silicon (Si), chromium (Cr), and nickel (Ni) may be included in an amount of 30 wt% or more, 40 wt% or more, or 50 wt% or more. The bonding layer including the carbide of the metal chemically increases the bonding strength between the diamond layer and the cover layer made of the metal, and at the same time has a thermal expansion coefficient between the thermal expansion coefficient of the cover layer and the thermal expansion coefficient of the diamond layer.

[0090] The heat dissipation member according to the second embodiment can be manufactured through the following process, but the present invention is not necessarily limited thereto.

[0091] The method for manufacturing a diamond sheet in which a facet structure consisting of (100), (101) and / or (111) crystal planes is formed on the surface while ensuring that the surface roughness (Ra) is in the most desirable range of 1 to 3 ㎛ is the same as that of the first embodiment.

[0092] A titanium (Ti) layer approximately 300 nm thick is coated on both sides of the diamond sheet manufactured in this manner as a bonding layer. At this time, at the interface between the diamond and titanium (Ti), some of the carbon (C) and titanium (Ti) that make up the diamond may react to form titanium carbide (TiC). Sputtering was used as the titanium (Ti) coating method, but other methods such as PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition) can also be used.

[0093] After a 50㎛ thick copper (Cu) plate is laminated on both sides of the diamond sheet on which the titanium (Ti) coating layer is formed, spark plasma sintering is used to sinter at approximately 1000℃, and a heat dissipation member having a laminated structure as shown in Fig. 8 is finally manufactured.

[0094] In this way, the manufactured heat dissipation member was able to obtain good adhesive properties such as no cracks during the discharge plasma sintering process and no peeling of the cover layer, similar to the first embodiment.

[0095] In addition, in order to confirm whether the heat dissipation member manufactured according to the second embodiment maintains good bonding strength between the cover layer and the diamond sheet even in an environment where low-temperature and high-temperature thermal shocks are repeatedly applied, a thermal cycle test was conducted on the heat dissipation member.

[0096] The thermal cycle test was performed by immersing the manufactured heat-radiating member in a -20℃ refrigerant for 10 seconds, then heating it on a hot plate heated to 350℃ for 3 minutes (one cycle), repeating the cooling-heating cycle 100 times, and observing the interface state between the cover layer and the diamond sheet before and after the thermal cycle test to see if bubbles or peeling occurred at the interface.

[0097] Fig. 9 shows a cross-sectional image (left) of a heat dissipation member manufactured according to the second embodiment and the EDS mapping result (right) thereof, and Fig. 10 shows a cross-sectional image (left) of a heat dissipation member of Fig. 9 after applying a cooling-heating thermal shock between low temperature (-20°C) and high temperature (350°C) and the EDS mapping result (right) thereof.

[0098] As confirmed in the electron microscope image of Fig. 9 and the image mapping its components (C: diamond sheet, Ti: bonding layer, Cu: cover layer), no bubbles or peeling were observed between the diamond sheet, titanium (Ti) bonding layer, and copper (Cu) cover layer.

[0099] In addition, as confirmed in Fig. 10, even after 100 cycles of cooling-heating, no bubbles or peeling were observed between the diamond sheet, titanium (Ti) bonding layer, and copper (Cu) cover layer, and thus the bonding state was maintained the same as the initial state.

[0100]

[0101] [Embodiment 3]

[0102] Fig. 11 is a cross-sectional view of a heat dissipation member according to a third embodiment of the present invention. In the third embodiment, the remaining configuration, except for the two-layer bonding layer, is the same as in the second embodiment, and therefore, a description thereof is omitted.

[0103] Referring to Fig. 11, the bonding layer is formed as a multilayer structure of a first bonding layer and a second bonding layer. The bonding layer is not limited to two layers and may be formed as a multilayer structure of three or more layers.

[0104] The materials constituting the first bonding layer and the second bonding layer may include one or more metals selected from titanium (Ti), tungsten (W), silicon (Si), chromium (Cr), and nickel (Ni) and / or carbides thereof, and are made of materials having different compositions.

[0105] In addition, it is preferable that the second bonding layer formed on the upper surface of the diamond layer is made of a material having a lower coefficient of thermal expansion than the first bonding layer formed on the second bonding layer. In addition, it is preferable that the first bonding layer is made of a material having a lower coefficient of thermal expansion than the cover layer. In this way, through a bonding layer having a multilayer structure in which the coefficient of thermal expansion gradually increases, a more improved bonding force can be obtained between the diamond layer and the cover layer.

[0106]

[0107] [Embodiment 4]

[0108] Fig. 12 is a cross-sectional view of a heat dissipation member according to a fourth embodiment of the present invention. In the fourth embodiment, the remaining configuration, except for the copper (Cu)-diamond composite layer formed on the opposite side of the cover layer formed on one side of the diamond layer, is the same as in the first embodiment, and therefore, a description thereof is omitted.

[0109] The copper (Cu)-diamond composite layer is made of a composite material in which a large number of diamond particles are dispersed within a matrix made of copper (Cu) or a copper (Cu) alloy (hereinafter referred to as the “copper (Cu) matrix”).

[0110] The copper (Cu)-diamond composite layer has a higher thermal conductivity and lower coefficient of thermal expansion than copper (Cu), so it can increase the thermal conductivity of the entire heat dissipation member while lowering the coefficient of thermal expansion.

[0111] When a copper (Cu)-diamond composite layer contains less than 10% by volume of diamond particles in a copper (Cu) matrix, it is difficult to achieve a low thermal expansion coefficient and the thermal conductivity required to quickly discharge heat generated in a high-power device. When it contains more than 80%, the thermal conductivity becomes good, but it is not easy to combine the diamond particles and the thermal expansion coefficient also becomes excessively low. Therefore, it is preferable to contain 10 to 80%. More preferably, the volume ratio of the diamond particles may be 15 to 70%, and most preferably, the volume ratio of the diamond particles may be 30 to 60%.

[0112] In addition, the size of the diamond particles to be composited can be 100㎛ or more in terms of improving thermal conductivity, preferably 200㎛ or more, more preferably 300㎛ or more, and most preferably 400㎛ or more.

[0113] The thickness of the above copper (Cu)-diamond composite layer is preferably 150 to 1500 ㎛. If the thickness is less than 150 ㎛, breakage or warping may occur, and if it exceeds 1500 ㎛, the coefficient of thermal expansion becomes excessively large and the thermal conductivity decreases.

[0114] Additionally, a bonding layer of the second embodiment may be formed between the diamond layer and the cover layer made of metal and / or the copper (Cu)-diamond composite layer.

[0115]

[0116] [Embodiment 5]

[0117] Fig. 13 is a cross-sectional view of a heat dissipation member according to a fifth embodiment of the present invention. The heat dissipation member according to the fifth embodiment is characterized by forming a copper (Cu)-diamond composite layer on the upper and lower surfaces of the diamond layer instead of the cover layer of the first embodiment. The composition and thickness of the diamond layer and the copper (Cu)-diamond composite layer are the same as those of the fourth embodiment, and therefore, a description thereof is omitted.

[0118] Through a structure such as the fifth embodiment, the thermal conductivity on the upper and lower sides of the diamond layer can be increased and the thermal expansion coefficient can be maintained low.

[0119] Additionally, bonding layers of the second and third embodiments can be formed between the diamond layer and the copper (Cu)-diamond composite layer.

[0120]

[0121] [Embodiment 6]

[0122] Fig. 14 is a cross-sectional view of a heat dissipation member according to the sixth embodiment of the present invention.

[0123] The above heat dissipation member comprises a heat dissipation member according to the fourth embodiment and a heat exchange member bonded to a copper (Cu)-diamond composite layer constituting the heat dissipation member.

[0124] In the heat dissipation member according to the fourth embodiment, the cover layer is made of copper (Cu) or an alloy thereof and is a surface that comes into contact with the electronic element.

[0125] The above heat exchange member is made of copper (Cu) or an alloy thereof, and a number of heat dissipation fins may be formed on the opposite side that comes into contact with the heat dissipation member.

[0126]

[0127] [Embodiment 7]

[0128] Fig. 15 is a cross-sectional view of a heat dissipation member according to the seventh embodiment of the present invention.

[0129] A heat dissipation member according to the seventh embodiment comprises a rectangular parallelepiped diamond core manufactured by a CVD method and a cover layer formed on all surfaces of the diamond core.

[0130] At least one surface of the above diamond core has a surface roughness (Ra) controlled to a range of 0.05 to 5 μm in the same manner as in the first embodiment, and has a facet structure composed of (100), (101) and / or (111) crystal planes.

[0131] The above cover layer may preferably be made of copper (Cu) or an alloy thereof.

[0132] Additionally, a bonding layer of the second and third embodiments may be formed between the diamond core and the cover layer.

[0133]

[0134] [Embodiment 8]

[0135] Fig. 16 is a cross-sectional view of a heat dissipation member according to the eighth embodiment of the present invention.

[0136] A heat dissipation member according to the eighth embodiment comprises a diamond sheet manufactured by a CVD method and a cover layer formed on both sides of the diamond sheet.

[0137] The above diamond sheet has one or more through holes formed therein, the through holes being filled with an electrically conductive material (e.g., copper (Cu) or an alloy thereof), and a cover layer formed in a predetermined shape by connecting the through holes formed on both sides of the diamond sheet. In Fig. 16, the cover layer is formed in a circular shape on the front side to cover the through holes, and in a shape extending toward a corner portion of the square-shaped diamond sheet while covering the through holes on the back side, but the shape is not necessarily limited to this shape, and may be formed in various shapes.

[0138] The surface of the diamond sheet bonded to the above cover layer has a surface roughness (Ra) controlled to a range of 0.05 to 5 µm in the same manner as in the first embodiment, and has a facet structure composed of (100), (101) and / or (111) crystal planes.

[0139] The above cover layer may preferably be made of copper (Cu) or an alloy thereof.

[0140] Additionally, a bonding layer of the second and third embodiments may be formed between the diamond sheet and the cover layer.

[0141]

[0142] [Embodiment 9]

[0143] Fig. 17 is a cross-sectional view of a heat dissipation member according to the ninth embodiment of the present invention.

[0144] A heat dissipation member according to the 9th embodiment comprises a diamond sheet manufactured by a CVD method and a cover layer formed on one surface of the diamond sheet.

[0145] The above cover layer is made of a copper (Cu)-diamond composite layer, and this copper (Cu)-diamond composite layer is the same as that described in the fourth embodiment.

[0146] On the opposite side of the cover layer (the upper side in the drawing) that comes into contact with the diamond sheet, protruding heat dissipation fins are formed. These protruding heat dissipation fins increase the contact area with air or refrigerant, thereby enabling faster heat dissipation.

[0147]

[0148] [Embodiment 10]

[0149] Fig. 18 is a cross-sectional view of a heat dissipation member according to the 10th embodiment of the present invention.

[0150] A heat dissipation member according to the 10th embodiment comprises a diamond sheet manufactured by a CVD method and a cover layer formed on both sides of the diamond sheet.

[0151] The above cover layer is made of copper (Cu) or an alloy thereof.

[0152] One of the two layers covering the above diamond sheet is formed in a form in which the diamond sheet is exposed in a predetermined pattern as shown in Fig. 18.

Claims

1. A diamond layer with a thickness of 100㎛ or more formed by the CVD (Chemical Vapor Depositon) method, Including a cover layer formed on at least one surface of the above diamond layer, A heat dissipation member having a surface roughness (Ra) of a diamond layer on which the above cover layer is formed of 0.05 to 5㎛.

2. In paragraph 1, A heat dissipation member, wherein a bonding layer having a thermal expansion coefficient greater than that of the diamond layer and smaller than that of the cover layer is additionally formed between the diamond layer and the cover layer.

3. In paragraph 2, A heat dissipation member, wherein the bonding layer comprises at least one metal selected from titanium (Ti), tungsten (W), silicon (Si), chromium (Cr), and nickel (Ni) and / or a carbide thereof.

4. In paragraph 1, The above cover layer is a heat dissipation member made of copper (Cu) or a copper (Cu) alloy.

5. In paragraph 1, A heat dissipation member having a surface roughness (Ra) of the diamond layer on which the above cover layer is formed of 0.5 to 3.5㎛.

6. In paragraph 1, A heat dissipation member, wherein the surface of the diamond layer on which the cover layer is formed is regrown after polishing to have a facet structure composed of (100), (101) and / or (111) crystal planes.

7. In paragraph 1, A heat dissipation member in which the above diamond layer has a polycrystalline structure, and the average size of diamond grains measured by EBSD on the surface of the diamond layer on which the cover layer is formed is 10㎛ or less.

8. In paragraph 1, The above CVD method is MPCVD (Microwave Plasma Chemical Vapor Depositon), a heat-radiating member.

9. In paragraph 1, A heat dissipation member, wherein some of the above cover layers are made of a copper (Cu)-diamond composite material in which diamond particles are dispersed in a copper (Cu) or copper (Cu) alloy matrix.

10. In paragraph 1, The thermal conductivity (W / mK) of the above heat dissipation member is 600 W / mK or more, At 25℃, the coefficient of thermal expansion is 2×10 -6 / K ~ 10×10 -6 / K, heat dissipation member.

11. A heat dissipation member having a heat exchange part formed in the shape of a plurality of protrusions on one side of the heat dissipation member described in any one of clauses 1 to 10.

12. A heat-radiating member, wherein a pattern of a predetermined shape is formed on the cover layer of the heat-radiating member described in any one of clauses 1 to 10 so that the diamond layer is exposed.

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