TWI797722B - Composite substrate and manufacture method thereof - Google Patents

Abstract

A composite substrate is provided in some embodiments of the present disclosure, including a heat dissipation substrate, a connection layer and an epitaxial structure. A thermal conductivity coefficient of the heat dissipation substrate is higher than 140W/ mK. The connection layer is disposed on the heat dissipation substrate, in which the connection layer is an inorganic compound, and a thermal conductivity coefficient of the connection layer is higher than 20W/ mK. The epitaxial structure includes a silicon wafer disposed on the connection layer and an epitaxial multi-layer disposed on the silicon wafer, in which a material of the epitaxial multi-layer includes gallium nitride (GaN). A method of manufacturing a composite substrate is also provided in some embodiments of the present disclosure.

Description

Composite substrate and manufacturing method thereof

The present disclosure relates to composite substrates and methods of making the same.

Recently, high-power components based on GaN have been continuously improved and improved in design and process based on the needs of consumer electronics and automotive components. However, with the demand for miniaturization of size and continuous improvement of power, the heat accumulation effect of GaN power components increases rapidly due to the increase of power density, which reduces performance and poses serious challenges to reliability and stability.

Therefore, how to improve the heat dissipation effect of the composite substrate containing GaN high-power components is a problem to be solved.

An object of an embodiment of the present disclosure is to provide a composite substrate, comprising: a heat dissipation substrate with a thermal conductivity higher than 140 W/mK; a connection layer disposed on the heat dissipation substrate with a thermal conductivity higher than 20 W/mK; and The epitaxial structure includes a silicon wafer disposed on the connecting layer and an epitaxial multilayer disposed on the silicon wafer, wherein the epitaxial multilayer includes gallium nitride.

In some embodiments, the connection layer includes aluminum nitride, aluminum oxynitride, zinc oxide, tin oxide, magnesium oxide, aluminum oxide, or any combination of two or more of the foregoing materials.

In some embodiments, the roughness of the tie layer is less than 50 nanometers.

In some embodiments, the epitaxial multilayer of the epitaxial structure includes: a nucleation layer disposed on a silicon wafer, comprising aluminum nitride; a buffer layer disposed on the nucleation layer, comprising aluminum gallium nitride, gallium nitride, or A combination of any two or more of the aforementioned materials; the resistance layer is disposed on the buffer layer and includes gallium nitride; the channel layer is disposed on the resistance layer and includes gallium nitride; the barrier layer is disposed on the channel layer and includes gallium nitride aluminum gallium; and a capping layer, disposed on the barrier layer, comprising gallium nitride.

The purpose of one embodiment of the present disclosure is to provide a method for manufacturing a composite substrate, including: coating a colloidal solution on the surface of the silicon wafer in the epitaxial structure and the surface of the heat dissipation substrate, respectively coating the surface of the silicon wafer and the surface of the heat dissipation substrate. Forming the first pre-connection layer and the second pre-connection layer on the surface of the substrate; heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate; in a vacuum environment, the first pre-connection layer and the second pre-connection layer The two pre-connection layers are attached to each other, so that the epitaxial structure and the heat dissipation substrate are connected; in the nitrogen-containing gas condition, the first pre-connection layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate are heated to obtain a composite substrate .

In some embodiments, the epitaxial structure includes a silicon wafer and an epitaxial multilayer including GaN disposed on the silicon wafer, and the surface of the silicon wafer is opposite to the surface of the epitaxial multilayer.

In some embodiments, the step of preparing the colloidal solution comprises mixing a metal-containing compound, a carbon-containing compound, an amine-containing compound, a surfactant, and a solvent.

In some embodiments, after the step of heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure, and the heat dissipation substrate, it further includes: performing a planarization process on the first pre-connection layer and the second pre-connection layer; and An activation process is performed on the planarized first pre-connection layer and the second pre-connection layer to increase dangling bonds on the surfaces of the first pre-connection layer and the second pre-connection layer.

In some embodiments, the step of the activation process includes: performing plasma treatment, ozone treatment, oxidation solution treatment, or a combination of any two or more of the foregoing treatments on the first pre-connection layer and the second pre-connection layer.

In some embodiments, the step of heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure, and the heat dissipation substrate in a nitrogen-containing gas condition includes: heating the first pre-connection layer, the second pre-connection layer in multiple stages Pre-connection layer, epitaxy structure and heat dissipation substrate.

It can be understood that different implementations or examples provided in the following content can implement different features of the subject matter of the present disclosure. The examples of specific components and arrangements are used to simplify the present disclosure and not to limit the present disclosure. Of course, these are examples only and are not intended to be limiting. For example, the description below that a first feature is formed on a second feature includes that the two are in direct contact, or that there are other additional features between the two instead of direct contact. In addition, the present disclosure may repeat reference numerals and/or symbols in several embodiments. Such repetition is for simplicity and clarity and does not imply a relationship between the various embodiments and/or configurations discussed.

The terms used in this specification generally have their ordinary meanings in the art and the context in which they are used. The examples used in this specification, including examples of any term discussed herein, are illustrative only and do not limit the scope and meaning of the disclosure or any exemplified term. Likewise, the disclosure is not limited to some of the embodiments provided in this specification.

In addition, relative terms in space, such as "below" and "upper", are used to conveniently describe the relative relationship between one element or feature and other elements or features in the drawings. These spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. The device may be otherwise positioned (eg, rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

In this article, "a" and "the" can generally refer to one or more, unless the article is specifically limited in the context. It will be further understood that the terms "comprising", "comprising", "having" and similar words used herein indicate the features, regions, integers, steps, operations, elements and/or components described therein, but do not exclude Other features, regions, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that, although the terms first, second etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present embodiments.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Several implementations are listed below to describe the touch device of the present invention in more detail, but they are only for illustrative purposes and are not intended to limit the present invention. The scope of protection of the present invention shall prevail as defined by the scope of the appended patent application .

First, see Figure 1. FIG. 1 exemplarily depicts a flowchart of a method 100 for manufacturing a composite substrate in some embodiments of the present disclosure, including step S110, providing an epitaxial structure; step S120, providing a heat dissipation substrate; step S130, mixing a metal-containing compound, A carbon-containing compound, an amine-containing compound, a surfactant, and a solvent to obtain a colloidal solution; step S140, coating the colloidal solution on the surface of the epitaxial silicon wafer and the surface of the heat dissipation substrate to form a first pre-connection layer and The second pre-connection layer; step S150, heating the first pre-connection layer on the surface of the silicon wafer, the second pre-connection layer on the surface of the heat dissipation substrate, the epitaxial structure, and the heat dissipation substrate; step S160, in a vacuum environment, bonding the first pre-connection layer and the second pre-connection layer to each other, so that the epitaxial structure is connected to the heat dissipation substrate; and step S170, heating the first pre-connection layer, the second pre-connection layer layer, an epitaxial structure, and a heat dissipation substrate, the first pre-connection layer and the second pre-connection layer are bonded as a connection layer, and a composite substrate is obtained.

In order to describe the method 100 more clearly and in detail, the steps in FIG. 1 will be described below in conjunction with FIG. 2A to FIG. 2H . 2A to 2H exemplarily depict cross-sectional schematic views of various process stages for manufacturing a composite substrate in accordance with some embodiments of the present disclosure.

First, please refer to step S110 in FIG. 1 and FIG. 2A , providing an epitaxial structure 110 . The epitaxial structure 110 includes a silicon wafer 112 and an epitaxial multilayer 114 disposed on the silicon wafer 112. The material in the epitaxial multilayer 114 includes gallium nitride. The silicon wafer surface 112A of the silicon wafer 112 is relatively opposite to the epitaxial multilayer Epitaxial multilayer surface 114A of 114 . In some embodiments, the epitaxial multilayer 114 is a high-frequency component. It should be noted that as the power density increases and the size decreases, the heat accumulation effect will increase accordingly. Reduced performance when in use.

In some embodiments, the epitaxial multilayer 114 sequentially includes a nucleation layer disposed on the silicon wafer 112, a buffer layer disposed on the nucleation layer, a resistive layer disposed on the buffer layer, a channel layer disposed on the resistive layer, a barrier A layer is disposed on the channel layer, and a cover layer is disposed on the barrier layer. In some embodiments, the nucleation layer may comprise aluminum nitride and have a thickness between 30 nm and 300 nm. In some embodiments, the buffer layer may comprise AlGaN, GaN, or a combination of any two or more of the foregoing materials, such as ladder AlGaN or superlattice AlGaN/N GaN, thickness between 300nm and 1000nm. In some embodiments, the resistance layer is gallium nitride, and its thickness may be between 0.5 microns and 2.5 microns. In some embodiments, the channel layer is GaN with a thickness between 0.05 micron and 1 micron. In some embodiments, the barrier layer comprises aluminum gallium nitride and has a thickness between 10 nm and 50 nm. In some embodiments, the capping layer is GaN with a thickness of 0.5 nm to 150 nm.

In some embodiments, in response to subsequent process requirements, as shown in FIG. 2B , the silicon wafer 112 can be thinned after the epitaxial structure 110 is provided, so that the thickness of the thinned silicon wafer 112 is less than 10 microns. In some embodiments, in order to prevent the epitaxial structure 110 from being too thin and warping after thinning the silicon wafer 112 , before thinning the silicon wafer 112 , glue that can be fixed by ultraviolet light or conventional bonding can be used. technology, a temporary substrate is disposed on the epitaxial multilayer 114, and the temporary substrate is removed after the method 100 is completed. In some embodiments, please refer to FIG. 2A at the same time. In order to improve the bonding effect between the epitaxial multilayer 114 and the temporary substrate, an activation process (such as plasma treatment, ozone treatment, oxidation solution treatment, or Any two or more of the aforementioned treatments) to increase the dangling bonds on the epitaxial multilayer surface 114A; then, a temporary substrate is placed on the epitaxial multilayer 114 by bonding technology. Through the activation process, the bonding effect between the epitaxial multilayer 114 and the temporary substrate is improved.

Next, please refer to step S120 in FIG. 1 and FIG. 2C , providing a heat dissipation substrate 120 .

In some embodiments, the heat dissipation substrate 120 is a material with high thermal conductivity, for example, the thermal conductivity is higher than 140W/mK. In some embodiments, the material of the heat dissipation substrate 120 includes silicon carbide (with a thermal conductivity of 370W/mK), aluminum nitride (with a thermal conductivity of 140W/mK to 180W/mK), gallium nitride (with a thermal conductivity of 253W/mK), Diamond (or diamond, thermal conductivity 2300W/mK), beryllium oxide (thermal conductivity 209W/mK to 330W/mK), graphene (thermal conductivity higher than 5300W/mK) or high heat dissipation ceramic substrate (thermal conductivity at least higher than 140W/mK). In some embodiments, the heat dissipation substrate 120 may have a single crystal structure, a polycrystalline structure, an amorphous silicon structure, or a combination of any two or more of the aforementioned materials.

In some embodiments, the heat dissipation substrate 120 has a thickness of 150 microns to 1500 microns, for example, 150 microns, 200 microns, 250 microns, 300 microns, 350 microns, 400 microns, 450 microns, 500 microns, 550 microns, 600 microns Micron, 650 micron, 700 micron, 750 micron, 800 micron, 850 micron, 900 micron, 950 micron, 1000 micron, 1050 micron, 1100 micron, 1150 micron, 1200 micron, 1250 micron, 1300 micron, 1350 micron, 1400 micron, 1450 microns, 1500 microns or any value in the aforementioned range.

Next, please refer to step S130 to step S140 in FIG. 1 and FIG. 2D. Step S130, mixing metal-containing compounds, carbon-containing compounds, amine-containing compounds, surfactants, and solvents to obtain a colloidal solution. Step S140 , coating a colloidal solution on the surface 112A of the silicon wafer of the epitaxial structure 110 and the surface 120A of the heat dissipation substrate 120 to form the first pre-connection layer 131 and the second pre-connection layer 132 .

In some embodiments, the metal-containing compound comprises nitrates, nitrate hydrates (eg, Al(NO ₃ ) ₃ -9H ₂ O), metal chlorides (eg, AlCl ₃ ), metal oxides (eg, aluminum oxide ( Al ₂ O ₃ ) or any combination of two or more of the aforementioned materials. In some embodiments, the carbon-containing compound includes glucose, starch, sucrose, or any combination of two or more of the aforementioned materials. In some In some embodiments, the amine-containing compound comprises glycine, urea (CO(NH ₂ ) ₂ ), or any two or more combinations of the aforementioned materials. In some embodiments, the surfactant comprises a non-ionic surfactant (eg, Pluronic® F108). In some embodiments, the solvent includes water, an organic substance (eg, ethanol), or a combination of any two or more of the foregoing.

In some embodiments, the step of mixing the metal-containing compound, the carbon-containing compound, the amine-containing compound, the surfactant, and the solvent comprises mixing and stirring the metal-containing compound, the carbon-containing compound, the amine-containing compound, the surfactant, and water , Through the surfactant, the metal compound, carbon-containing compound, and amine-containing compound are uniformly dissolved in water, and the metal compound, carbon-containing compound, and amine-containing compound undergo a chemical reaction to generate an inorganic compound with high thermal conductivity (such as nitrogen aluminum oxide, aluminum oxynitride, zinc oxide, tin oxide, magnesium oxide, aluminum oxide, or any two or more of the aforementioned materials) and a gelation mixed solution. For example, aluminum oxide reacts with carbon and ammonia to form aluminum nitride which is distributed in the mixed solution, and carbon monoxide and hydrogen are by-products. In some embodiments, the temperature can be adjusted at 15°C based on the properties of different additives. In the range of °C to 80 °C, mixing and stirring are carried out. Next, heating the metal-containing compound, carbon-containing compound, amine-containing compound, surfactant, and water (for example, at a temperature ranging from 40°C to 90°C) for at least 0.5 hours to partially dehydrate the mixed solution, reduce Water content, drying the mixed solution, increasing the viscosity of the mixed solution, so as to obtain a viscous colloidal solution containing inorganic compounds with high thermal conductivity.

Specifically, in some embodiments, the metal-containing compound, carbon-containing compound, amine-containing compound, surfactant, and water can be mixed and stirred at a temperature of 15°C to 40°C for 0.5 hours to 5 hours. hour, obtain a mixed solution; then, heat the mixed solution at a temperature of 60°C to 90°C for 0.5 hour to 5 hours, and obtain a colloidal solution. In other embodiments, the metal-containing compound, carbon-containing compound, amine-containing compound, surfactant, and water can be mixed and stirred at a temperature of 40°C to 80°C for 2 hours to obtain a mixed solution; Next, the mixed solution was heated at a temperature of 40° C. for 2 hours to obtain a colloidal solution. Through proper temperature and time control, better mixing, gelling, and viscous effects can be achieved through dehydration. For example, if the heating and dehydration time is too long, the colloidal solution will be too viscous, which will easily cause uneven subsequent coating, and reduce the connection and heat dissipation effect after bonding. If the heating and dehydration time is too short, the colloid solution will be too dilute and the fluidity will be too high, which will also easily cause uneven subsequent coating.

In some embodiments, if the amine-containing compound is urea, and the metal-containing compound contains aluminum, the molar ratio of urea to aluminum may be 0.8 to 1.2, such as 0.8, 0.9, 1, 1.1, 1.2 or any of the aforementioned intervals Numerical value, and the atomic number ratio of carbon and aluminum in the carbon-containing compound may be 5 to 15, such as 5, 10, 15 or a value in any of the aforementioned intervals. It is worth noting that the generation efficiency of inorganic compounds with high thermal conductivity can be improved through the regulation of appropriate colloidal solution components and element ratios.

In some embodiments, the step of coating the colloidal solution on the surface 112A of the silicon wafer and the surface 120A of the heat dissipation substrate 120 includes spinning coating (for example, at 1000 rpm (rotation speed per minute, Revolution(s) Per Minute) to 3500 rpm), roll coating, or other coating methods, coating the colloidal solution on the silicon wafer surface 112A of the epitaxial structure 110 and the surface 120A of the heat dissipation substrate 120 for 0.5 hours to 5 hours, forming a thickness of 0.5 μm to 50 μm of the first pre-connection layer 131 and the second pre-connection layer 132; then, at a temperature of 80°C to 250°C (eg, 80°C to 120°C or 90°C to 250°C) , dry (dehydrate) the first pre-connection layer 131 and the second pre-connection layer 132, improve the viscosity of the first pre-connection layer 131 and the second pre-connection layer 132, increase the first pre-connection layer 131 and the second pre-connection layer The degree of fixation of the layer 132 on the surface 112A of the silicon wafer and the surface 120A of the heat dissipation substrate 120 respectively. In some embodiments, the aforementioned coating and drying steps can be repeated to increase the thickness of the first pre-connection layer 131 and the second pre-connection layer 132 according to the requirements of thickness and heat dissipation efficiency, for example, 1 to 20 times.

In some embodiments, the individual thicknesses of the first pre-connection layer 131 and the second pre-connection layer 132 are 0.5 microns to 50 microns, for example, 0.5 microns, 1 micron, 2 microns, 3 microns, 4 microns, 5 microns. Micron, 10 micron, 20 micron, 30 micron, 40 micron, 50 micron or any value in the aforementioned range.

Next, see step S150 in FIG. 1 and FIG. 2E , heating the first pre-connection layer 131 on the surface 112A of the silicon wafer, the second pre-connection layer 132 on the surface 120A of the heat dissipation substrate 120 , and the epitaxial structure 110 , and the heat dissipation substrate 120 (for example, heat energy H1 is applied from the epitaxial structure 110 side and the heat dissipation substrate 120 side, respectively). In some embodiments, the heating can be performed in two stages at a temperature greater than 80°C. For example, the first pre-connection layer 131, the second pre-connection layer 132, the epitaxial structure 110, and the heat dissipation substrate 120 are heated at a temperature of 90°C to 250°C; In the gas condition of ammonia or nitrogen), the temperature is raised from 25°C to 1200°C, and the first pre-connection layer 131, the second pre-connection layer 132, the epitaxial The crystal structure 110 and the heat dissipation substrate 120 , wherein the temperature of each stage can be maintained for 2 to 10 hours, and the ratio of hydrogen to nitrogen-containing gas (such as ammonia or nitrogen) is 5:95 to 1:99. Through the step of heating, other substances (such as surfactants, water, etc.) in the first pre-connection layer 131 and the second pre-connection layer 132 except the inorganic compound with high thermal conductivity are further removed, and the inorganic compound with high thermal conductivity in the colloid solution is The compound remains in the first pre-connection layer 131 and the second pre-connection layer 132 , and strengthens the adhesion between the first pre-connection layer 131 and the silicon wafer surface 112A and the second pre-connection layer 132 and the surface 120A of the heat dissipation substrate 120 .

It is worth mentioning that the inorganic compound with high thermal conductivity has a porous structure. Therefore, in the subsequent bonding and heating steps (such as step S160 and step S170), even if a small amount of gas is generated, the gas can be introduced into the pores of the inorganic compound to avoid gaps between the bonded surfaces due to the presence of gas , affecting the fitting effect.

In some embodiments, it is also possible to repeat step S140 (coating colloid solution) to step S150 (heating the first pre-connection layer 131, the second pre-connection layer 132, epitaxial structure 110, and heat dissipation substrate 120). It is worth emphasizing that the flatness and porosity of the first pre-connection layer 131 and the second pre-connection layer 132 can be adjusted through the coating times and the type or content of the inorganic compound in the colloid solution. For example, the more coating times, the higher the flatness, or the higher the content of inorganic compounds, the denser the distribution and the lower the porosity.

In some embodiments, the method 100 further Including: performing a planarization process on the first pre-connection layer 131 and the second pre-connection layer 132 (for example, using a physical or chemical planarization process), so that the roughness of the first pre-connection layer 131 and the second pre-connection layer 132 The thickness is less than 50 nanometers, such as less than 10 nanometers, less than 20 nanometers, less than 30 nanometers, and less than 40 nanometers, so as to increase the adhesion of the subsequent first pre-connection layer 131 and the second pre-connection layer 132, and improve the bonding. effect; and the planarized first pre-connection layer 131 and the second pre-connection layer 132 are activated to increase the dangling bonds on the surface 131A of the first pre-connection layer 131 and the surface 132A of the second pre-connection layer 132, thereby improving the subsequent The bonding effect between the first pre-connection layer 131 and the second pre-connection layer 132 . In some embodiments, the step of performing the activation process on the first pre-connection layer 131 and the second pre-connection layer 132 includes: performing plasma treatment, ozone treatment, oxidation on the first pre-connection layer 131 and the second pre-connection layer 132 Liquid treatment or a combination of any two or more of the aforementioned treatments.

Next, please refer to step S160 in FIG. 1 and FIG. 2F. Step S160, in a vacuum environment, attach the first pre-connection layer 131 and the second pre-connection layer 132 to each other (along the direction D), so that the epitaxial structure 110 and the heat dissipation substrate 120 are connected, wherein the first pre-connection layer 131 and the second pre-connection layer 132 are located between the epitaxial structure 110 and the heat dissipation substrate 120 . By performing the bonding step in a vacuum environment, it is possible to prevent the gas from causing voids or reacting with the first pre-connection layer 131 or the second pre-connection layer 132 , thereby reducing the adhesion of the bonding.

Next, please refer to step S170 in FIG. 1 , and FIG. 2G to FIG. 2H . Step S170, in the nitrogen-containing gas condition, heating the first pre-connection layer 131, the second pre-connection layer 132, the epitaxial structure 110, and the heat dissipation substrate 120 (for example, from the epitaxial structure 110 side and the heat dissipation substrate 120 side Apply heat energy (H2) to bond the first pre-connection layer 131 and the second pre-connection layer 132 as the connection layer 134 to obtain the composite substrate 200 .

In some embodiments, the nitrogen-containing gas can be used at a temperature of 400°C to 1200°C (for example, 400°C, 500°C, 600°C, 700°C, 800°C, 900°C C, 1000°C, 1100°C, 1200°C or any value in the aforementioned range) heating the first pre-connection layer 131 , the second pre-connection layer 132 , the epitaxial structure 110 , and the heat dissipation substrate 120 . In some embodiments, the first pre-connection layer 131, the second pre-connection layer 132, the epitaxial structure 110, and the heat dissipation substrate 120 can be heated in multiple stages, wherein the gas conditions include hydrogen and nitrogen, hydrogen and ammonia, or nitrogen and Ammonia to enhance bonding. In some embodiments, the heating time is 0.5 hours to 12 hours (eg, 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours hours, 12 hours, or any value within the preceding range).

It is worth noting that, through heat treatment (such as step S150 and step S170), most of the components in the first pre-connection layer 131 and the second pre-connection layer 132 are removed by high temperature (for example, water will evaporate due to high temperature, carbon will be oxidized carbon dioxide, dissipated in the air, etc.), and only the highly thermally conductive inorganic compound remains as the connection layer 134 .

In some embodiments, the composite substrate 200 includes a heat dissipation substrate 120, the connection layer 134 is disposed on the heat dissipation substrate 120, and the epitaxial structure 110 is disposed on the connection layer 134 (specifically, the silicon wafer 112 is disposed on the connection layer 134 , the epitaxial multilayer 114 is disposed on the silicon wafer 112), the materials and characteristics of the epitaxial structure 110 and the heat dissipation substrate 120 are as described in step S110 and step S120 respectively, and will not be repeated here. The connection layer 134 is an inorganic compound with pores (such as aluminum nitride, aluminum oxynitride, zinc oxide, tin oxide, magnesium oxide, aluminum oxide or any two or more combinations of the aforementioned materials), and the roughness is less than 50nm (for example, less than 10nm, less than 20nm, less than 30nm, less than 40nm), and the thermal conductivity is higher than 20W/mK. Compared with the conventional thermally conductive adhesive, the connection layer 134 not only has a better heat dissipation effect, but also can withstand higher temperatures (such as an annealing process greater than 500°C) in the subsequent process, which helps to improve the design of the subsequent process on the elasticity.

In summary, some embodiments of the present disclosure provide composite substrates and methods of manufacturing the same. Colloidal solution coating is used to manufacture the connection layer composed of high thermal conductivity inorganic compounds, and the arrangement method is flexible (spin coating, roller coating, etc.) Coating, etc.), and compared with the known thermally conductive adhesive, it has a better heat dissipation effect, and when applied to high-frequency components, it can more effectively reduce the heat accumulation effect; in addition, it can also withstand high temperatures of at least 500°C process, improving the design flexibility of subsequent processes.

While this disclosure has described details in terms of certain implementations, other implementations are possible. Therefore, the spirit and scope of the appended claims should not be limited to the implementations described herein.

100: method S110, S120, S130, S140, S150, S160, S170: steps 110: Epitaxial structure 112: Silicon wafer 112A: Silicon wafer surface 114: epitaxial multilayer 114A: Epitaxial multilayer surface 120: heat dissipation substrate 120A: surface 131: The first pre-connection layer 131A: Surface 132: The second pre-connection layer 132A: surface 134: Connection layer 200: composite substrate D: Direction H1, H2: thermal energy

A more complete understanding of the present disclosure can be obtained by reading the following detailed description of the embodiments with reference to the accompanying drawings. Figure 1 schematically depicts a flow chart for fabricating a composite substrate in some embodiments of the present disclosure. 2A to 2H exemplarily depict cross-sectional schematic views of various process stages for manufacturing a composite substrate in accordance with some embodiments of the present disclosure.

110: Epitaxial structure 112: Silicon wafer 114: epitaxial multilayer 120: heat dissipation substrate 134: Connection layer 200: composite substrate

Claims (10)

A composite substrate, comprising: a heat dissipation substrate having a thermal conductivity higher than 140W/mK; a connection layer disposed on the heat dissipation substrate, including a first pre-connection layer and a first pre-connection layer disposed on the first pre-connection layer The second pre-connection layer, the first pre-connection layer and the second pre-connection layer have a thermal conductivity higher than 20W/mK, and the first pre-connection layer is in contact with the heat dissipation substrate; and an epitaxial structure including a silicon A wafer is disposed on the second pre-connection layer and an epitaxial multilayer disposed on the silicon wafer, wherein the epitaxial multilayer includes gallium nitride. The composite substrate according to claim 1, wherein the connecting layer comprises aluminum nitride, aluminum oxynitride, zinc oxide, tin oxide, magnesium oxide, aluminum oxide, or any two or more combinations of the aforementioned materials. The composite substrate as claimed in claim 1, wherein the roughness of the connection layer is less than 50 nanometers, and the roughness of the connection layer is the arithmetic mean deviation of the profile. The composite substrate as claimed in claim 1, wherein the epitaxial multilayer of the epitaxial structure comprises: a nucleation layer disposed on the silicon wafer, comprising aluminum nitride; a buffer layer disposed on the nucleation layer above, containing aluminum gallium nitride, gallium nitride, or any combination of the aforementioned materials; an impedance layer, disposed on the buffer layer, comprising gallium nitride; a channel layer, disposed on the impedance layer, comprising gallium nitride; a barrier layer, disposed on the channel layer, comprising aluminum gallium nitride; and A capping layer, disposed on the barrier layer, includes gallium nitride. A method for manufacturing a composite substrate, comprising: coating a colloidal solution on the surface of a silicon wafer in an epitaxial structure and a surface of a heat dissipation substrate, respectively on the surface of the silicon wafer and the surface of the heat dissipation substrate forming a first pre-connection layer and a second pre-connection layer, and the colloid solution contains an inorganic compound; heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate; In the ambient environment, the first pre-connection layer and the second pre-connection layer are attached to each other, so that the epitaxial structure is connected to the heat dissipation substrate; and in a nitrogen-containing gas condition, heating the first pre-connection layer layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate to obtain a composite substrate. The method as described in claim 5, wherein the epitaxial structure comprises a silicon wafer and an epitaxial multilayer comprising gallium nitride disposed on the silicon wafer, and a surface of the silicon wafer is opposite to the epitaxial A surface of a multilayer crystal. The method as described in claim item 5, wherein preparing the colloidal solution The liquid step includes mixing a metal-containing compound, a carbon-containing compound, an amine-containing compound, a surfactant and a solvent. The method according to claim 5, wherein after the step of heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate, further comprising: the first pre-connection layer and the performing a planarization process on the second pre-connection layer; and performing an activation process on the planarized first pre-connection layer and the second pre-connection layer to increase the first pre-connection layer and the second pre-connection layer Surface dangling bonds. The method according to claim 8, wherein the activation process includes: performing a plasma treatment, an ozone treatment, an oxidation solution treatment, or any two of the aforementioned treatments on the first pre-connection layer and the second pre-connection layer or a combination of two or more. The method as claimed in item 5, wherein the step of heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate in the nitrogen-containing gas condition comprises: heating the first pre-connection layer, the second pre-connection layer, the epitaxial structure and the heat dissipation substrate in stages.

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