Composite substrate structure, heterogeneous integration method and electronic device structure
By using a phase change release layer and a barrier layer with a composite substrate structure in the heterogeneous integration process, the challenges of processing rigidity and non-destructive release of non-standard wafer materials were solved, achieving low stress transfer and interface cleanliness, and simplifying the process flow.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI NOVEL SI INTEGRATION TECH CO LTD
- Filing Date
- 2025-12-31
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies for heterogeneous integration of non-standard wafer materials face challenges such as difficulty in balancing processing rigidity and non-destructive release, the "orange peel effect" during thermally induced phase transitions, and difficulties in cleaning interface contamination, leading to easy breakage of ultrathin films and difficulty in deformation control.
A composite substrate structure is adopted, including a support substrate, a functional layer and a preset substrate. The functional layer consists of a phase change release layer and a barrier layer. The phase change release layer softens at a specific temperature to provide a sliding interface, and the barrier layer provides rigid support at low temperature. The residual layer is removed by combining shear force and solvent/plasma etching to achieve low stress transfer.
Stable release and transfer of non-standard sized substrates were achieved, solving the problems of deformation control and interface cleanliness of ultrathin materials and simplifying the process flow.
Smart Images
Figure CN122054919A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and in particular to a composite substrate structure, a heterogeneous integration method, and an electronic device structure. Background Technology
[0002] With the advent of the post-Moore's Law era, devices are evolving towards higher frequencies, greater power, smaller sizes, and multifunctionality, placing increasingly stringent demands on substrate materials. Besides traditional silicon, III-V compound semiconductors such as gallium arsenide (GaAs) and indium phosphide (InP), wide-bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN), and piezoelectric / ferroelectric materials such as lithium niobate (LiNbO3) and aluminum nitride (AlN) are increasingly widely used in RF filters, optical communications, and high-power devices. However, these specialized materials face two major challenges in their fabrication and heterogeneous integration: First, the processing difficulties of non-standard wafers (small pieces). Due to high costs or limitations in growth technology, many high-performance semiconductor materials or functional crystals are often supplied in non-standard sizes (such as 2 inches, 3 inches), or even irregular small pieces, which typically have poor initial surface conditions, exhibiting problems such as high roughness, warping, scratches, or growth defects. Second, the challenges of transferring and integrating ultra-thin functional films. To obtain flexible, integrable, or performance-optimized devices, the aforementioned functional materials often need to be thinned to tens or even several micrometers below the required thickness, forming ultrathin films or self-supporting films. However, thin films exhibit extremely poor mechanical stability after thinning, making them highly susceptible to cracking, curling, or developing fissures during subsequent operations.
[0003] To achieve heterogeneous integration and micro / nano fabrication of these non-standard materials, temporary bonding and debonding (TBDB) technology has become the mainstream solution in the industry. This technology typically uses temporary adhesives (such as heat-release tape, UV-curable adhesive, or hot-melt wax) to fix the substrate to be processed onto a standard-sized carrier, which is then separated after thinning or processing is completed. Existing temporary bonding technologies have solved the fixation problem to some extent, but certain challenges remain when it comes to the high-precision processing and transfer of thin, heat / force sensitive materials.
[0004] First, single-layer bonding materials cannot simultaneously achieve both processing rigidity and non-destructive release. Existing bonding layers are mostly homogeneous single-layer structures. If low-melting-point or low-viscosity soft adhesives (such as ordinary hot melt waxes) are used to facilitate peeling, the bonding layer is highly susceptible to creep or softening under shear or thermal stress during chemical mechanical polishing (CMP) or high-temperature coating. This can lead to ripples, uneven thickness (TTV difference), or even edge chipping on the surface of the underlying ultrathin wafer. Conversely, if high-modulus, high-temperature resistant hard adhesives are selected to ensure processing accuracy, extremely high mechanical peeling forces or high-temperature carbonization treatments are often required during subsequent debonding. This is fatal for extremely thin and brittle functional films, easily causing growth cracks or breakage.
[0005] Secondly, there are the issues of the "orange peel effect" and stress transfer during the thermally induced phase transition. For bonding schemes employing a heat release mechanism, when the bonding layer is heated and transitions from a solid to a liquid / viscous flow state in preparation for separation, its volume typically expands or contracts, and its modulus drops sharply. For ultrathin functional films that have lost the support of a rigid substrate, this change in the fluidity of the underlying layer is directly transmitted to the film surface, causing micro-wrinkles (i.e., the "orange peel effect") or curling of the film at the moment of peeling. Especially for thermally mismatch-sensitive materials such as lithium niobate, direct contact with the heat release layer can easily lead to wafer cracking due to localized thermal stress concentration.
[0006] Furthermore, there are challenges related to interface contamination and cleaning. Traditional bonding methods involve direct contact between the functional wafer and the bonding material. After debonding, the back side of the wafer often retains organic matter that is difficult to remove. To completely remove these residues, strong organic solvent immersion or high-power plasma bombardment is usually required, which not only increases the complexity of the process but may also damage the fabricated precision micro / nano structures. Summary of the Invention
[0007] This application provides a composite substrate structure, a heterogeneous integration method, and an electronic device structure that enables the release and transfer of non-standard sized substrates.
[0008] On the one hand, this application provides a composite substrate structure, including a support substrate, a functional layer and a preset substrate stacked sequentially; The functional layer includes a phase change release layer and a barrier layer that are sequentially stacked along a direction away from the supporting substrate; The phase change release layer is solid at a temperature below a first preset temperature to provide adhesion, and softens or liquefies at a temperature above or equal to the first preset temperature to provide a sliding interface; the first preset temperature is the temperature at which the phase change release layer undergoes a phase change; the softening temperature or decomposition temperature of the barrier layer is a second preset temperature, which is greater than the first preset temperature, and when the temperature is below the first preset temperature, the elastic modulus of the barrier layer is greater than the elastic modulus of the phase change release layer, in order to maintain the morphological stability of the preset substrate.
[0009] Furthermore, the barrier layer is soluble in a preset solvent or is responsive to plasma etching; The thickness of the phase change release layer is 0.5 μm-20 μm, and the thickness of the barrier layer is 0.5 μm-60 μm; The surface roughness of the barrier layer is less than 10 nm.
[0010] Furthermore, the material of the phase change release layer is at least one of modified rosin resin, hydrocarbon polymer, cyclic olefin copolymer, low molecular weight thermoplastic resin or microcrystalline wax; The barrier layer is made of at least one of polyimide, benzocyclobutene, parylene, spin-coated glass, or photoresist. The preset substrate is at least one of lithium niobate, lithium tantalate, barium titanate, strontium titanate, barium strontium titanate, silicon carbide, gallium nitride, gallium oxide, aluminum oxide, aluminum nitride, gallium arsenide, indium phosphide, indium antimonide, or diamond.
[0011] Furthermore, the supporting substrate is a circular wafer of standard size, while the preset substrate is a wafer or fragment of non-standard size; The effective surface area of the preset substrate is less than or equal to the surface area of the supporting substrate, and the preset substrate is disposed in the geometric center region of the supporting substrate.
[0012] Furthermore, the first preset temperature ranges from 60℃ to 220℃, and the second preset temperature is greater than 220℃; The heating temperature during separation of the composite substrate structure is greater than the first preset temperature and less than the second preset temperature.
[0013] On the other hand, a method for heterogeneous integration based on the composite substrate structure described above is provided, the method comprising: A first preset material is coated onto a support substrate and cured to form a phase change release layer; A second preset material is coated on the side of the phase change release layer away from the supporting substrate to form a barrier layer, and the preset substrate is bonded to the barrier layer to obtain the composite substrate structure; The preset substrate is thinned, polished, or micro / nano-processed to form a functional thin film layer of preset thickness; The functional thin film layer is bonded to the target substrate, the temperature is raised to a preset temperature range, and a shear force is applied to cause the supporting substrate to slide and separate from the phase change release layer, thereby transferring the functional thin film layer onto the target substrate to obtain a heterogeneous integrated structure.
[0014] Further, the second predetermined material is coated on the side of the phase change release layer away from the supporting substrate to form a barrier layer, and the predetermined substrate is bonded to the barrier layer to obtain a composite substrate structure, including: The second preset material is coated on the side of the phase change release layer away from the supporting substrate, and then subjected to heat reflow treatment to form the barrier layer; the surface of the barrier layer is in a semi-cured state; the preset substrate is attached to the surface of the barrier layer and cured to obtain the composite substrate structure; or: The second preset material is coated on the side of the phase change release layer away from the supporting substrate to form an initial barrier layer; the initial barrier layer is in a fully cured state; the surface of the initial barrier layer is planarized to obtain the barrier layer with a flat surface; the planarization process is at least one of chemical mechanical polishing, hot surface reflow, or flying cut; the preset substrate is combined with the flat surface of the barrier layer to obtain the composite substrate structure.
[0015] Further, the applied shear force causes the supporting substrate to slide and separate from the phase change release layer, transferring the functional thin film layer onto the target substrate to obtain a heterogeneous integrated structure, including: Shear force is applied to cause the supporting substrate to slide and separate from the phase change release layer, the functional thin film layer is transferred to the target substrate, and the barrier layer remaining on the surface of the functional thin film layer is removed using a preset solvent or plasma ashing process to obtain the heterogeneous integrated structure.
[0016] On the other hand, a method for preparing a self-supporting functional thin film based on the composite substrate structure described above is provided, the method comprising: Construct the composite substrate structure comprising a supporting substrate, a functional layer, and a pre-defined substrate; the functional layer includes a phase change release layer and a barrier layer; The preset substrate is thinned to a preset thickness, and a frame carrier with a hollow structure is bonded to the edge of the thinned preset substrate; or a reinforced frame is prepared on the surface of the thinned preset substrate. The temperature is heated to above a first preset temperature to separate the supporting substrate from the phase change release layer, and the residual barrier layer is removed to obtain the self-supporting functional film.
[0017] On the other hand, a heterogeneous integrated electronic device structure is provided, including a target substrate, a non-standard-sized functional thin film transferred onto the target substrate, and electronic devices on the surface, wherein the non-standard-sized functional thin film is transferred onto the target substrate using the heterogeneous integration method described above.
[0018] The composite substrate structure, heterogeneous integration method, and electronic device structure provided in this application have the following technical advantages: The composite substrate structure in this application includes a support substrate, a functional layer, and a preset substrate stacked sequentially. The functional layer includes a phase change release layer and a barrier layer stacked sequentially along a direction away from the support substrate. The phase change release layer is solid at temperatures below a first preset temperature to provide adhesion, and softens or liquefies at temperatures above or equal to the first preset temperature to provide a sliding interface. The first preset temperature is the temperature at which the phase change release layer undergoes a phase change. The softening or decomposition temperature of the barrier layer is a second preset temperature, which is greater than the first preset temperature. Furthermore, at temperatures below the first preset temperature, the elastic modulus of the barrier layer is greater than that of the phase change release layer, thus maintaining the morphological stability of the preset substrate. By setting a thermally induced phase change release layer and a rigid process barrier layer between the support substrate and the substrate to be processed, this application not only provides stable support for the substrate to be processed but also enables the release and transfer of non-standard sized substrates in a low-stress, low-damage manner, while simultaneously solving the problems of deformation control and interface cleanliness during the transfer of ultrathin materials.
[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description
[0020] To more clearly illustrate the technical solutions and advantages in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of a composite substrate structure provided in the embodiments of this specification; Figure 2 This is a flowchart illustrating a method for heterogeneous integration based on a composite substrate structure, as provided in the embodiments of this specification. Figure 3This is a schematic diagram illustrating the structural changes during heterogeneous integration, as provided in the embodiments of this specification. Figure 4 This is a schematic diagram of a composite substrate structure and a heterogeneous integrated structure based on the composite substrate structure provided in the embodiments of this specification; Figure 5 This is a schematic diagram of another composite substrate structure and a heterogeneous integrated structure based on the composite substrate structure provided in the embodiments of this specification.
[0022] The corresponding labels in the attached figures are: 100-supporting substrate, 200-functional layer, 210-phase change release layer, 220-barrier layer, 300-preset substrate, and 400-target substrate. Detailed Implementation
[0023] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0024] The following describes a composite substrate structure of this application, and its schematic diagram is shown below. Figure 1 As shown, it includes a support substrate 100, a functional layer 200 and a preset substrate 300 stacked in sequence; The functional layer 200 includes a phase change release layer 210 and a barrier layer 220 sequentially stacked in a direction away from the support substrate 100. The phase change release layer 210 is solid when the temperature is below a first preset temperature to provide adhesion, and softens or liquefies when the temperature is above or equal to the first preset temperature to provide a sliding interface; the first preset temperature is the temperature at which the phase change release layer 210 undergoes a phase change; the softening or decomposition temperature of the barrier layer 220 is a second preset temperature, which is greater than the first preset temperature, and when the temperature is below the first preset temperature, the elastic modulus of the barrier layer 220 is greater than the elastic modulus of the phase change release layer 210, in order to maintain the morphological stability of the preset substrate 300.
[0025] In this embodiment, the composite substrate structure is a thermally reversible composite substrate structure used for heterogeneous integration. The composite substrate structure, from bottom to top, comprises a support substrate 100, a functional layer 200, and a preset substrate 300. The functional layer 200 includes a phase change release layer 210 (first sublayer) and a barrier layer 220 (second sublayer) stacked sequentially from bottom to top. The preset substrate 300 can serve as the substrate to be processed for heterogeneous integration.
[0026] The aforementioned phase change release layer 210 is a thermally induced phase change release layer 210, which has a phase change temperature. The phase change temperature is a first preset temperature. When the temperature is greater than or equal to the first preset temperature, the thermally induced phase change release layer 210 softens or liquefies to provide a sliding interface, allowing it to separate from the support substrate 100. When the temperature is less than the first preset temperature, the thermally induced phase change release layer 210 is solid to provide adhesion.
[0027] The aforementioned barrier layer 220 is a rigid process barrier layer 220, which is made of a chemically resistant material. Its softening temperature or decomposition temperature is a second preset temperature, which is higher than a first preset temperature. Furthermore, when the temperature is lower than the first preset temperature, the elastic modulus of the rigid process barrier layer 220 is greater than the elastic modulus of the thermally induced phase change release layer 210, thus maintaining the morphological stability of the preset substrate 300. When the thermally induced phase change release layer 210 undergoes a fluidity change due to heat, it provides stable support to the preset substrate 300 while preventing the fluidity change of the thermally induced phase change release layer 210 from being directly transmitted to the preset substrate 300, thus preventing excessive local thermal stress concentration when the preset substrate 300 directly contacts the thermally induced phase change release layer 210.
[0028] The embodiments of this application, through the setting of the above-mentioned functional layer 200, can not only provide stable support for the preset substrate 300 under normal processing conditions, but also prevent the preset substrate 300 from being damaged by micro-wrinkles or curling when the thermally induced phase change release layer 210 separates from the support substrate 100. It can realize the release and transfer of non-standard size substrates in a low-stress and low-damage manner.
[0029] In one exemplary embodiment, the barrier layer 220 is soluble in a preset solvent or the barrier layer 220 is responsive to plasma etching; The phase change release layer 210 has a thickness of 0.5 μm-20 μm, and the barrier layer 220 has a thickness of 0.5 μm-60 μm. The surface roughness of the barrier layer 220 is less than 10 nm.
[0030] In this embodiment, the barrier layer 220 is soluble in a specific chemical solvent, i.e., a preset solvent, or responsive to plasma etching, so that after the preset substrate 300 is separated from the support substrate 100, the barrier layer 220 can be removed from the surface of the preset substrate 300 by a non-thermal treatment method.
[0031] In this embodiment, the thickness of the phase change release layer 210 is 0.5 μm-20 μm, and the thickness of the barrier layer 220 is 0.5 μm-60 μm; the surface roughness (Ra) of the barrier layer 220 is less than 10 nm, and the macroscopic thickness uniformity (e.g., TTV) of the thermally induced phase change release layer 210 is at the micrometer level. For example, the total thickness deviation of the thermally induced phase change release layer 210 after coating and curing is less than 10 μm.
[0032] This application embodiment clarifies the material properties and thickness characteristics of the thermally induced phase change release layer 210 and the rigid process barrier layer 220 in the functional layer 200. By setting the material of the barrier layer 220 to be soluble in a preset solvent or to be responsive to plasma etching, the barrier layer 220 can be removed from the surface of the preset substrate 300 with a simple process after the preset substrate 300 is separated from the support substrate 100.
[0033] In an exemplary embodiment, the material of the phase change release layer 210 is at least one of modified rosin resin, hydrocarbon polymer, cyclic olefin copolymer, low molecular weight thermoplastic resin, or microcrystalline wax. The material of the barrier layer 220 is at least one of polyimide, benzocyclobutene, parylene, spin-coated glass, or photoresist. The preset substrate 300 is at least one of lithium niobate, lithium tantalate, barium titanate, strontium titanate, barium strontium titanate, silicon carbide, gallium nitride, gallium oxide, aluminum oxide, aluminum nitride, gallium arsenide, indium phosphide, indium antimonide, or diamond.
[0034] In this embodiment, the material of the thermally induced phase change release layer 210 is at least one of modified rosin resin, hydrocarbon polymer, cyclic olefin copolymer, low molecular weight thermoplastic resin, or microcrystalline wax; the material of the barrier layer 220 is at least one of polyimide (PI), benzocyclobutene (BCB), parylene, spin-coated glass (SOG), or photoresist; and the preset substrate 300 is at least one of lithium niobate, lithium tantalate, barium titanate, strontium titanate, barium strontium titanate (BST), silicon carbide, gallium nitride, gallium oxide, aluminum oxide, aluminum nitride, gallium arsenide, indium phosphide, indium antimonide, or diamond.
[0035] For example, to remove the barrier layer 220 on the preset substrate 300, if the material of the barrier layer 220 is photoresist, the preset solvent can be acetone, N-methylpyrrolidone (NMP), dimethyl sulfoxide, or a commercial photoresist remover, or plasma removal can be used; if the material of the barrier layer 220 is polyimide (PI) or benzocyclobutene (BCB), when it is not fully cured, the preset solvent can be cyclopentanone or mesitylene; after complete curing, the preset solvent can be a high-efficiency stripping solution or a developer containing amine compounds, or dry etching (oxygen plasma) removal can be used; if the material of the barrier layer 220 is spin-coated glass (SOG), the preset solvent can be hydrofluoric acid (HF) buffer (BOE) or diluted hydrofluoric acid (DHF); if the material of the barrier layer 220 is parylene, plasma removal is mainly used to remove the barrier layer 220 on the surface.
[0036] In one exemplary embodiment, the support substrate 100 is a circular wafer of standard size, and the preset substrate 300 is a wafer or fragment of non-standard size; The effective surface area of the preset substrate 300 is less than or equal to the surface area of the support substrate 100, and the preset substrate 300 is disposed in the geometric center region of the support substrate 100.
[0037] In this embodiment, the supporting substrate 100 is a circular wafer conforming to the semiconductor manufacturing equipment interface standard and has a standard size (4-inch / 6-inch / 8-inch / 12-inch). The preset substrate 300 is a non-standard size (2 / 3-inch wafer or other non-standard size wafer) wafer or fragment. The effective surface area of the preset substrate 300 is less than or equal to the surface area of the supporting substrate 100, and the preset substrate 300 is located in the geometric center region of the supporting substrate 100.
[0038] In one exemplary embodiment, the first preset temperature ranges from 60°C to 220°C, and the second preset temperature is greater than 220°C. The heating temperature during separation of the composite substrate structure is greater than the first preset temperature and less than the second preset temperature.
[0039] In this embodiment, the temperature range of the first preset temperature is 60℃-220℃, and the second preset temperature cannot be lower than the first preset temperature, that is, the second preset temperature is greater than 220℃, to ensure that when the thermally induced phase change layer softens or liquefies to provide a slip interface, the rigid process barrier layer 220 can remain stable and will not soften or decompose, thus maintaining the morphological stability of the preset substrate 300.
[0040] In this embodiment of the application, when it is necessary to separate the preset substrate 300 from the composite substrate structure, the thermally induced phase change release layer 210 can be softened or liquefied by heating to provide a sliding interface. The heating temperature is greater than the first preset temperature and less than the second preset temperature, so as to separate it from the support substrate 100 and transfer the preset substrate 300 to the target substrate 400 to achieve heterogeneous integration of non-standard size substrates.
[0041] The embodiments of this application specify the phase transition temperature of the thermally induced phase transition release layer 210 and the softening or decomposition temperature of the rigid process barrier layer 220, which enables the non-standard size preset substrate 300 in the composite substrate structure to separate from the support substrate 100 at a certain temperature, thereby realizing the heterogeneous integration of non-standard size substrates.
[0042] The following describes a method for heterogeneous integration based on the composite substrate structure described above, as per this application. Specifically, as follows... Figure 2 and Figure 3 As shown, the method may include: S100: A first preset material is coated on the support substrate 100 and cured to form a phase change release layer 210; S200: A second preset material is coated on the side of the phase change release layer 210 away from the support substrate 100 to form a barrier layer 220, and the preset substrate 300 is combined with the barrier layer 220 to obtain the composite substrate structure. S300: Thinning, polishing or micro / nano processing is performed on the preset substrate 300 to form a functional thin film layer of preset thickness; S400: The functional thin film layer is bonded to the target substrate 400, the temperature is raised to a preset temperature range, and a shear force is applied to cause the support substrate 100 to slide and separate from the phase change release layer 210, thereby transferring the functional thin film layer onto the target substrate 400 to obtain a heterogeneous integrated structure.
[0043] In this embodiment, a first preset material is coated and cured on a support substrate 100 to form a phase change release layer 210, i.e., a first sublayer, on the support substrate 100. Then, a second preset material is coated on the side of the phase change release layer 210 away from the support substrate 100 to form a barrier layer 220, i.e., a second sublayer. A non-standard sized preset substrate 300, i.e., the substrate to be processed, is bonded to the side of the barrier layer 220 away from the support substrate 100 to obtain a composite substrate structure. The preset substrate 300 in the composite substrate structure is thinned, polished, or micro / nano-processed to form a functional thin film layer of a preset thickness. The functional thin film layer is bonded to a target substrate 400, and the temperature is raised to a preset range to soften or liquefy the phase change release layer 210 to provide a sliding interface. Shear force is then applied to cause the support substrate 100 and the phase change release layer 210 to slide and separate, thereby transferring the functional thin film layer onto the target substrate 400 to obtain a heterogeneous integrated structure.
[0044] In this embodiment, the preset temperature range is the temperature range between the first preset temperature and the second preset temperature. The first preset temperature is the temperature at which the phase change release layer 210 softens or liquefies, and the second preset temperature is the temperature at which the barrier layer 220 softens or decomposes.
[0045] For example, the preset thickness can be 0.1 μm-100 μm.
[0046] For example, the first preset material can be at least one of modified rosin resin, hydrocarbon polymer, cyclic olefin copolymer, low molecular weight thermoplastic resin or microcrystalline wax; the second preset material can be at least one of polyimide, benzocyclobutene, parylene, spin-coated glass or photoresist.
[0047] The composite substrate structure in this embodiment can provide stable support for the substrate to be processed during the conventional processing stage. By setting the phase change release layer 210 and the barrier layer 220, it can also realize the release and transfer of non-standard size films in a low-stress and low-damage manner, while solving the problems of deformation control and interface cleanliness of ultrathin materials during the transfer process.
[0048] In an exemplary embodiment, coating the side of the phase change release layer 210 away from the supporting substrate 100 with a second preset material to form a barrier layer 220, and then bonding the preset substrate 300 to the barrier layer 220 to obtain a composite substrate structure, may include: The second preset material is coated on the side of the phase change release layer 210 away from the support substrate 100, and a heat reflow treatment is performed to form a barrier layer 220; the surface of the barrier layer 220 is in a semi-cured state; the preset substrate 300 is attached to the surface of the barrier layer 220 and cured to obtain the composite substrate structure. or; The second preset material is coated on the side of the phase change release layer 210 away from the support substrate 100 to form an initial barrier layer; the initial barrier layer 220 is in a fully cured state; the surface of the initial barrier layer is planarized to obtain the barrier layer 220 with a flat surface; the planarization process is at least one of chemical mechanical polishing, hot surface reflow, or flying cut; the preset substrate 300 is combined with the flat surface of the barrier layer 220 to obtain the composite substrate structure.
[0049] In this embodiment, the bonding of the preset substrate 300 and the barrier layer 220 includes two methods. One method is to perform a heat reflow treatment after coating with the second preset material to planarize the surface of the barrier layer 220 and keep it in a semi-cured state, then attach the preset substrate 300 and perform a curing treatment to obtain a composite substrate structure.
[0050] In this embodiment, the temperature of the reflow treatment needs to be higher than the glass transition temperature of the material, but significantly lower than the curing / crosslinking temperature, and the reflow treatment time should be short to prevent premature curing. For example, the temperature of the reflow treatment can be 80°C-150°C, and the reflow treatment time can be 1 min-30 min.
[0051] In this embodiment, the curing process is either thermosetting or photosetting. Thermosetting is used to induce a cross-linking reaction in the polymer material, making it more rigid and forming a corrosion-resistant rigid barrier layer 220. Because the first sublayer is sealed between the support substrate 100 and the bonded second sublayer / substrate to be processed, even if the first sublayer softens during thermosetting, its material is confined within the interlayer interface and will not leak. Furthermore, hydrostatic pressure helps to further improve the flatness of the overall structure. For example, the temperature of the thermosetting process can be 150°C-300°C, and the time can be 15 min-300 min.
[0052] In this embodiment of the application, if photocuring is used, a photosensitive material or an ultraviolet curing material can be added to the second preset material, and photocuring can be completed by ultraviolet irradiation at room temperature to obtain a composite substrate structure.
[0053] In this embodiment, another method for bonding the preset substrate 300 and the barrier layer 220 is to directly cure the first sublayer after coating the surface of the second preset material, so that the initial barrier layer is in a fully cured state. Then, the surface of the initial barrier layer is planarized to obtain a barrier layer 220 with a flat surface. The planarization process can be at least one of chemical mechanical polishing (CMP), hot surface reflow, or flying shearing. Subsequently, a wetting layer or an adhesive layer is spin-coated onto the surface of the polished barrier layer 220, or the surface is subjected to plasma activation treatment, or the substrate to be processed is bonded to the second sublayer by hot pressing to obtain a composite substrate structure.
[0054] In the embodiments of this application, the two combinations of the preset substrate 300 and the barrier layer 220 can reduce the thickness non-uniformity generated after spin coating of the first sublayer and reduce the overall TTV value.
[0055] In one exemplary embodiment, the application of shear force to cause the supporting substrate 100 to slide and separate from the phase change release layer 210, transferring the functional thin film layer onto the target substrate 400, to obtain a heterogeneous integrated structure, includes: Shear force is applied to cause the supporting substrate 100 to slide and separate from the phase change release layer 210, the functional thin film layer is transferred to the target substrate 400, and the barrier layer 220 remaining on the surface of the functional thin film layer is removed using a preset solvent or plasma ashing process to obtain the heterogeneous integrated structure.
[0056] In this embodiment, when the temperature rises to a preset temperature range, the phase change release layer 210 in the composite substrate structure softens or liquefies to provide a sliding interface. At this time, applying shear force can cause the supporting substrate 100 to slide and separate from the phase change release layer 210, achieving low-stress and low-damage release. Furthermore, when the supporting substrate 100 and the phase change release layer 210 slide and separate, the barrier layer 220 can still provide rigid support for the substrate to be processed, preventing the flow changes between the supporting substrate 100 and the phase change release layer 210 from being directly transmitted to the film surface, preventing the film from developing micro-wrinkles or curling, and avoiding the substrate to be processed from cracking due to local thermal stress concentration when the film directly contacts the phase change release layer 210.
[0057] In this embodiment, after the functional thin film layer is transferred onto the target substrate 400, the residual barrier layer 220 on the surface of the functional thin film layer can be removed using a preset solvent or plasma ashing process to obtain a heterogeneous integrated structure. Alternatively, the second sublayer can be directly retained as a passivation layer to obtain a heterogeneous integrated structure with a passivation layer.
[0058] The embodiments of this application can remove the residue on the surface of the functional thin film layer with a simple process, and can also directly use the barrier layer 220 as a passivation layer, which simplifies the heterogeneous integration process and solves the problems of deformation control and interface cleanliness during the transfer of ultrathin films.
[0059] This application also provides a method for preparing a self-supporting functional thin film based on the composite substrate structure described above, the method including: A composite substrate structure is constructed containing a support substrate 100, a functional layer 200, and a pre-defined substrate 300; the functional layer 200 includes a thermally induced phase change release layer 210 and a rigid process barrier layer 220. Thin the preset substrate 300 to a preset thickness; the preset thickness is 0.1 μm-100 μm. A hollow frame carrier is bonded to the edge of a thinned pre-substrate 300; or a reinforced frame is fabricated on the surface of the pre-substrate 300. The temperature is heated to above the first preset temperature to separate the support substrate 100 from the thermally induced phase change release layer 210, and the residual barrier layer 220 is removed to obtain a self-supporting functional film fixed on the frame carrier.
[0060] In this embodiment, the composite substrate structure can also be used to prepare a self-supporting functional film. After the composite substrate structure is prepared according to the aforementioned method, the preset substrate 300 in the composite substrate structure, i.e. the substrate to be processed, is thinned to a thickness of 0.1 μm-100 μm. Then, a frame carrier with a hollow structure is bonded to the edge of the thinned preset substrate 300, or a reinforced frame is directly prepared on the surface of the preset substrate 300. The temperature is heated to a temperature above the first preset temperature and below the second preset temperature. The thermally induced phase change release layer 210 softens or liquefies to provide a sliding interface, so that the support substrate 100 is separated from the thermally induced phase change release layer 210. Then, the residual barrier layer 220 on the surface is removed using a preset solvent or by plasma etching process to obtain a self-supporting functional film fixed on the frame carrier.
[0061] This application embodiment also provides a heterogeneous integrated electronic device structure, including a target substrate 400, a non-standard sized functional thin film transferred onto the target substrate 400, and electronic devices on the surface, wherein the thickness of the functional thin film is 0.1 μm-100 μm, and the surface of the functional thin film away from the target substrate 400 retains residues of the rigid process barrier layer 220 from the composite substrate structure as described above, or the surface has plasma treatment traces left after removing the rigid process barrier layer 220, and the functional thin film is transferred onto the target substrate 400 using the heterogeneous integration method as described above.
[0062] Example 1: Example 1 provides a composite substrate structure and a method for heterogeneous integration using the composite substrate structure. The composite substrate structure includes, from bottom to top, a silicon support substrate layer, a phase change release layer, a barrier layer, and an Er-doped LN substrate (erbium-doped lithium niobate substrate). The phase change release layer uses high-purity electronic wax with a melting point of approximately 80°C; the barrier layer uses styrene-cyclobutene (BCB), which exhibits good flatness after curing; the lithium niobate material includes intrinsic lithium niobate, magnesium-doped lithium niobate, erbium-doped lithium niobate, or other rare-earth element-doped lithium niobate. Figure 4 As shown, the method for preparing the above-mentioned composite substrate structure and using it for heterogeneous integration includes: Electronic wax was spin-coated onto a silicon support substrate to a thickness of 10 μm and then baked at 100°C to level it. BCB adhesive was spin-coated onto the wax layer at 3000 rpm, with a thickness of approximately 3 μm. A 3-inch lithium niobate wafer was bonded onto the incompletely cured BCB and then slowly cured in a vacuum oven at 150°C for 4 hours. The LN film was thinned to 600 nm by grinding and CMP. Heat the temperature to 90°C to liquefy the electronic wax, then gently push the silicon wafer apart. The residual wax was cleaned with trichloroethylene, and the BCB layer was retained as the lower cladding layer for subsequent photonic devices, resulting in a heterogeneous integrated structure. This heterogeneous integrated structure includes a target substrate 400 layers, an Er-doped LN thin film, and a BCB layer.
[0063] Example 2: Example 2 provides another composite substrate structure and a method for heterogeneous integration using the composite substrate structure. This composite substrate structure includes, from bottom to top, a sapphire substrate layer, a phase change release layer, a barrier layer, and a gallium oxide substrate. The phase change release layer is made of modified rosin resin with a softening point of 130°C; the barrier layer is made of spin-coated glass, whose hardness after curing is close to that of silicon dioxide, providing extremely strong rigid support and barrier; the gallium oxide substrate has high hardness, requiring strong support during CMP polishing to prevent edge collapse. Figure 5 As shown, the method for preparing the above-mentioned composite substrate structure and using it for heterogeneous integration includes: Rosin resin was spin-coated onto a sapphire substrate to a thickness of 20 μm and then baked at 150°C. SOG material was spin-coated at 4000 rpm to a thickness of 1 μm, and then cured at 250℃ to transform it into a hard SiO2-like glass layer. The SOG layer was subjected to short-time CMP polishing to obtain nanoscale flatness, and then an ultrathin (0.2μm) photoresist was spin-coated as a wetting layer, which was then bonded to the gallium oxide substrate by hot pressing. Gallium oxide substrates are thinned by grinding and CMP; The temperature was heated to 160°C to soften and allow the rosin resin to slide. The resin was then immersed in a hydrofluoric acid buffer to rapidly remove any residual SOG layer from the gallium nitride (GaN) film surface, resulting in a heterogeneous integrated structure. This heterogeneous integrated structure comprises a 400-layer target substrate and a GaN film.
[0064] Example 3: Example 3 provides another composite substrate structure, comprising, from bottom to top, a silicon substrate layer, a phase change release layer, a barrier layer, and an indium phosphide substrate. The phase change release layer is made of cyclic olefin copolymer (COC), with a thickness of 30 μm and a softening point of 140°C, and can be removed after heating to 180°C. The barrier layer is made of polyimide (PI), with a thickness of 5 μm, which is spin-coated and hot-pressed at 120°C, followed by curing at 200°C. It can be removed during subsequent heterogeneous integration using a dedicated stripping solution or plasma ashing.
[0065] Example 4: Example 4 provides another composite substrate structure, comprising, from bottom to top, a sapphire substrate layer, a phase change release layer, a barrier layer, and a barium titanate substrate. The phase change release layer is made of microcrystalline wax, with a thickness of 15 μm, and can be removed by heating to 90°C; the barrier layer is made of parylene C, prepared by CVD (chemical vapor deposition), with a thickness of 2 μm, and an extremely thin UV adhesive is coated on the surface of the barrier layer for bonding the barium titanate bulk.
[0066] As can be seen from the embodiments provided in this application above, the composite substrate structure in this application includes a support substrate, a functional layer, and a preset substrate stacked sequentially. The functional layer includes a phase change release layer and a barrier layer stacked sequentially along a direction away from the support substrate. The phase change release layer is solid at temperatures below a first preset temperature to provide adhesion, and softens or liquefies at temperatures above or equal to the first preset temperature to provide a sliding interface. The first preset temperature is the temperature at which the phase change release layer undergoes a phase change. The softening or decomposition temperature of the barrier layer is a second preset temperature, which is greater than the first preset temperature. Furthermore, at temperatures below the first preset temperature, the elastic modulus of the barrier layer is greater than the elastic modulus of the phase change release layer, thus maintaining the morphological stability of the preset substrate. By providing a thermally induced phase change release layer and a rigid process barrier layer between the support substrate and the substrate to be processed, this application not only provides stable support for the substrate to be processed but also enables the release and transfer of non-standard sized substrates in a low-stress, low-damage manner, while simultaneously solving the problems of deformation control and interface cleanliness during the transfer of ultra-thin materials.
[0067] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A composite substrate structure, characterized in that, It includes a support substrate, a functional layer and a preset substrate stacked in sequence; The functional layer includes a phase change release layer and a barrier layer that are sequentially stacked along a direction away from the supporting substrate; The phase change release layer is solid at a temperature below a first preset temperature to provide adhesion, and softens or liquefies at a temperature above or equal to the first preset temperature to provide a sliding interface; the first preset temperature is the temperature at which the phase change release layer undergoes a phase change; the softening temperature or decomposition temperature of the barrier layer is a second preset temperature, which is greater than the first preset temperature, and when the temperature is below the first preset temperature, the elastic modulus of the barrier layer is greater than the elastic modulus of the phase change release layer, in order to maintain the morphological stability of the preset substrate.
2. The composite substrate structure according to claim 1, characterized in that, The barrier layer is soluble in a preset solvent or is responsive to plasma etching; The thickness of the phase change release layer is 0.5 μm-20 μm, and the thickness of the barrier layer is 0.5 μm-60 μm; The surface roughness of the barrier layer is less than 10 nm.
3. The composite substrate structure according to claim 1, characterized in that, The material of the phase change release layer is at least one of modified rosin resin, hydrocarbon polymer, cyclic olefin copolymer, low molecular weight thermoplastic resin or microcrystalline wax. The barrier layer is made of at least one of polyimide, benzocyclobutene, parylene, spin-coated glass, or photoresist. The preset substrate is at least one of lithium niobate, lithium tantalate, barium titanate, strontium titanate, barium strontium titanate, silicon carbide, gallium nitride, gallium oxide, aluminum oxide, aluminum nitride, gallium arsenide, indium phosphide, indium antimonide, or diamond.
4. The composite substrate structure according to claim 1, characterized in that, The supporting substrate is a circular wafer of standard size, while the preset substrate is a wafer or fragment of non-standard size; The effective surface area of the preset substrate is less than or equal to the surface area of the supporting substrate, and the preset substrate is disposed in the geometric center region of the supporting substrate.
5. The composite substrate structure according to claim 2, characterized in that, The first preset temperature ranges from 60℃ to 220℃, and the second preset temperature is greater than 220℃; The heating temperature during separation of the composite substrate structure is greater than the first preset temperature and less than the second preset temperature.
6. A method for heterogeneous integration based on the composite substrate structure according to any one of claims 1-5, characterized in that, The method includes; A first preset material is coated onto a support substrate and cured to form a phase change release layer; A second preset material is coated on the side of the phase change release layer away from the supporting substrate to form a barrier layer, and the preset substrate is bonded to the barrier layer to obtain the composite substrate structure; The preset substrate is thinned, polished, or micro / nano-processed to form a functional thin film layer of preset thickness; The functional thin film layer is bonded to the target substrate, the temperature is raised to a preset temperature range, and a shear force is applied to cause the supporting substrate to slide and separate from the phase change release layer, thereby transferring the functional thin film layer onto the target substrate to obtain a heterogeneous integrated structure.
7. The method according to claim 6, characterized in that, The second preset material is coated on the side of the phase change release layer away from the supporting substrate to form a barrier layer, and the preset substrate is bonded to the barrier layer to obtain a composite substrate structure, including: The second preset material is coated on the side of the phase change release layer away from the supporting substrate, and a heat reflow treatment is performed to form the barrier layer; the surface of the barrier layer is in a semi-cured state; the preset substrate is attached to the surface of the barrier layer and cured to obtain the composite substrate structure; or; The second preset material is coated on the side of the phase change release layer away from the supporting substrate to form an initial barrier layer; the initial barrier layer is in a fully cured state; the surface of the initial barrier layer is planarized to obtain the barrier layer with a flat surface; the planarization process is at least one of chemical mechanical polishing, hot surface reflow, or flying cut; the preset substrate is combined with the flat surface of the barrier layer to obtain the composite substrate structure.
8. The method according to claim 6, characterized in that, The applied shear force causes the supporting substrate to slide and separate from the phase change release layer, transferring the functional thin film layer onto the target substrate to obtain a heterogeneous integrated structure, including: Shear force is applied to cause the supporting substrate to slide and separate from the phase change release layer, the functional thin film layer is transferred to the target substrate, and the barrier layer remaining on the surface of the functional thin film layer is removed using a preset solvent or plasma ashing process to obtain the heterogeneous integrated structure.
9. A method for preparing a self-supporting functional thin film based on the composite substrate structure according to any one of claims 1-5, characterized in that, The method includes: Construct the composite substrate structure comprising a supporting substrate, a functional layer, and a pre-defined substrate; the functional layer includes a phase change release layer and a barrier layer; The preset substrate is thinned to a preset thickness, and a frame carrier with a hollow structure is bonded to the edge of the thinned preset substrate; or a reinforced frame is prepared on the surface of the thinned preset substrate. The temperature is heated to above a first preset temperature to separate the supporting substrate from the phase change release layer, and the residual barrier layer is removed to obtain the self-supporting functional film.
10. A heterogeneous integrated electronic device structure, characterized in that, The invention includes a target substrate, a non-standard-sized functional thin film transferred onto the target substrate, and electronic devices on the surface, wherein the non-standard-sized functional thin film is transferred onto the target substrate using the method described in any one of claims 6-8.