Large size flexible diamond exfoliation bonding method for device heat dissipation

Abstract

The application relates to the field of high-power electronic device heat dissipation, and mainly relates to a large-size flexible diamond exfoliation bonding method for device heat dissipation. The large-size flexible diamond exfoliation bonding method for device heat dissipation comprises the following steps: pre-stress gradient release type lossless exfoliation of a large-size flexible diamond film, deposition of a low-temperature alloy layer, and center-edge gradient bonding of a diamond composite film and a chip. The application forms a full-process closed-loop scheme from exfoliation stress regulation, interface transition layer design to bonding structure optimization in view of technical defects such as traditional diamond film exfoliation difficulty, easy breakage and wrinkle, surface easy damage and pollution, alloy layer poor combination, high bonding interface thermal resistance, easy warping and falling off and oxidation failure, and firmly and low-resistance connection and long-acting and efficient heat dissipation of the large-size flexible diamond and the chip are efficiently realized.

Description

Technical Field

[0001] This application relates to the field of heat dissipation in high-power electronic devices, and mainly to a method for large-size flexible diamond peeling and bonding for heat dissipation of devices. Background Technology

[0002] Diamond, as a novel functional material with ultra-high thermal conductivity (up to 2000-2500 W / (m·K)), excellent chemical stability, good electrical insulation, and mechanical wear resistance, has irreplaceable application value in high-power electronic devices, optoelectronic devices, microwave devices, and other fields. Especially in the field of heat dissipation for high-power electronic devices, its superior thermal conductivity effectively solves the problem of heat accumulation during device operation.

[0003] The current mainstream technology route in the industry is to use MPCVD technology to grow flexible diamond films on smooth and polished silicon wafers, and then construct diamond-chip heat dissipation structures through peeling, metal transition layer deposition, and bonding processes. This approach has become the core preparation method for diamond heat dissipation devices due to its advantages such as high diamond growth quality, good compatibility with silicon wafers, ability to achieve large-size preparation, and relatively controllable cost.

[0004] However, existing technologies still suffer from numerous systemic defects and technical bottlenecks, severely restricting device performance and reliability: Significant internal stress accumulates at the interface between the diamond film grown by MPCVD and the silicon substrate. Existing mechanical peeling methods generally rely on unidirectional tensile force, lacking interface stress control and gradient buffer design, making large-size films prone to stress concentration, breakage, wrinkling, and other morphological damage due to improper force and angle control; chemical etching methods easily cause chemical residues and interface contamination on the film surface, impairing the intrinsic thermal conductivity of diamond and the smoothness of subsequent bonding. Neither of these methods can achieve high-quality, non-destructive peeling of large-size flexible diamonds.

[0005] Meanwhile, existing methods for preparing metal transition layers before bonding often employ a single metal layer or high-temperature processes. High-temperature environments can easily damage the diamond lattice structure and reduce its intrinsic high thermal conductivity. Furthermore, the single metal layer has poor matching degree between the thermal expansion coefficients of diamond and the chip, resulting in weak interfacial bonding. The bonding stage uses uniform temperature control and pressure processes across the entire domain, without differentiated structural design for the interfacial stress distribution. Under the combined effects of long-term high-temperature cycling, mechanical vibration, humid and hot environments, and electron radiation, problems such as diamond film cracking, alloy layer oxidation and detachment, bonding interface warping and loosening, increased interfacial thermal resistance, and broken heat conduction pathways are highly likely to occur. These problems can lead to decreased device heat dissipation efficiency, abnormal operating temperature, local overheating damage, decreased operational stability, and even short-circuit failure.

[0006] Furthermore, the traditional lift-deposition-bonding process lacks integrated collaborative design, and the parameters of each step are not matched and adapted. It also suffers from derivative problems such as lift-aid materials being intolerant to high temperatures, poor film uniformity, bonding positioning deviation, and easy residue of impurities at the interface. It cannot simultaneously achieve complete and non-destructive lift of diamond film, dense and low-resistivity deposition of transition layer, and strong and low-resistivity bonding of chip. As a result, the overall service life, heat dissipation performance, and environmental adaptability of diamond heat dissipation devices cannot meet the requirements of long-term stable and reliable operation of high-power electronic devices.

[0007] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0008] In view of the shortcomings of the existing technology, and addressing the technical defects of traditional diamond film peeling, such as difficulty in peeling, easy breakage and wrinkling, easy surface damage and contamination, weak alloy layer bonding, high thermal resistance at the bonding interface, easy warping and detachment, and oxidation failure, the purpose of this application is to provide a large-size flexible diamond peeling and bonding method for device heat dissipation. The method aims to provide an integrated preparation process through pre-stress gradient release non-destructive peeling, PVD low-temperature deposition of indium gallium aluminum alloy, center-edge gradient bonding, heating and pressurization and nitrogen-protected bonding. The process conditions, material selection and interface effects of each step have been precisely adapted and synergistically optimized. From peeling stress control and interface transition layer design to bonding structure optimization, a closed-loop solution is formed to efficiently achieve a firm, low-resistance connection between large-size flexible diamond and the chip and long-term efficient heat dissipation.

[0009] The technical solution of this application is as follows: A method for large-size flexible diamond peel bonding for device heat dissipation includes the following steps: A gradient composite layer is generated on a substrate, and then a diamond film to be peeled is deposited on the gradient composite layer to obtain the peelable part; the interface of the peelable part is modified by stepwise ultraviolet irradiation; the diamond film to be peeled is separated from the gradient composite layer to obtain a large-size flexible diamond film. An alloy layer is generated on the smooth polished surface of a large-size flexible diamond film to obtain a diamond composite film; The bonding interface is divided with the chip's geometric center as the reference. The central strong bonding area is a circular core area that accounts for 65-75% of the chip's radial dimension, while the remaining outer annular area is the edge stress-relieving area. A Ti-Au or Ti-Ag bilayer metal transition layer is sputtered on the surface of the strong bonding region at the center of the chip corresponding to the diamond composite film. A buffer structure is set in the stress-relieving region at the chip edge corresponding to the diamond composite film; the buffer structure includes a metal Cr base layer and a nano-oxide layer. A diamond composite film with a double-layer metal transition layer and a buffer structure on its surface is defined as a bonding compound; The bonding compound is precisely aligned with the heat dissipation area of ​​the chip, with an alignment deviation of no more than 50μm; The bonding temperature in the central strong bonding zone is 250-300℃, and the bonding temperature in the edge stress-relieving zone is 150-200℃. A continuous temperature field transition zone is set between the center and the edge. The bonding pressure is 0.3-0.5MPa, and the temperature and pressure are maintained for 10-20 minutes to complete the bonding.

[0010] Furthermore, the provision of a buffer structure in the stress-relief region at the edge of the chip corresponding to the diamond composite film includes: sputtering the metal Cr underlayer in the stress-relief region at the edge of the chip corresponding to the diamond composite film; and then using plasma oxidation or ultraviolet oxidation to generate the nano oxide layer in situ on the metal Cr underlayer. The thickness of the buffer structure is 10-30 nm.

[0011] Furthermore, the stepwise ultraviolet irradiation of the part to be peeled to modify the interface includes: taking the geometric center of the part to be peeled as a reference, 65-75% of the radial area is defined as the central area, and the remaining annular area on the outside is defined as the edge area. The edge region has a wavelength of 240–280 nm and a power of 20–30 mW / cm. 2 Under these conditions, subject to strong radiation for 5–8 minutes; Then, the entire area of ​​the component to be stripped is subjected to a wavelength of 240–280 nm and a power of 5–10 mW / cm. 2 Under these conditions, perform weak irradiation for 1-2 minutes; The edge area is then treated at 80-100℃ and the center area at 40-60℃.

[0012] Furthermore, the separation of the diamond film to be peeled from the gradient composite layer of the part to be peeled includes: Apply the tape to the non-growth surface of the diamond film to be peeled off; The tape end is clamped and pulled at a constant tension and small angle. During the peeling process, the pulling angle is continuously and gently adjusted, and the overall dynamic change is within the range of 15°-45°. Combined with the straight and uniform speed traction, separation is achieved. A chemical solution method was used to separate the PI tape from the diamond film to be peeled off, resulting in a large-size flexible diamond film.

[0013] Furthermore, the gradient composite layer is formed by magnetron sputtering of SiO2, Ag, Ti, and Au.

[0014] Furthermore, during the generation of the gradient composite layer, the sputtering power of the Ag, Ti, and Au metal targets maintains a synchronous linear gradient, keeping the power ratio of Ag:Ti:Au at (4.5-5.5):(2.5-3.5):(1.5-2.5), while the sputtering power of the SiO2 target remains unchanged. At the start of sputtering, the total sputtering power of the Ag, Ti, and Au metal targets is 120–150W, and the sputtering power of the SiO2 target is 70–90W. At the end of sputtering, the total sputtering power of the Ag, Ti, and Au metal targets is 20–40W, and the sputtering power of the SiO2 target is 70–90W.

[0015] Furthermore, the alloy layer includes an indium gallium aluminum alloy layer.

[0016] Furthermore, the formation of the indium gallium aluminum alloy layer includes: using an indium gallium aluminum alloy target as a sputtering source, a sputtering power of 80-120W, a distance of 8-12cm between the target and the diamond film, a sputtering gas flow rate of 20-30sccm, a deposition time of 10-30min, and a chamber temperature of 80-150℃ during the deposition process.

[0017] Furthermore, the thickness of the indium gallium aluminum alloy layer is 50-200 nm; The adhesion between the indium gallium aluminum alloy layer and the diamond film surface is not less than 15 N / cm. 2 .

[0018] Furthermore, the step of sputtering a Ti-Au or Ti-Ag bilayer metal transition layer on the surface of the strong bonding region at the center of the diamond composite film includes: Using the diamond composite film as a substrate, a pure Ti target is sputtered with a DC power of 80–120W to deposit a Ti adhesive layer on the surface of the strong bonding region at the center of the chip corresponding to the diamond composite film. Then, sputter an Au or Ag target with a DC power of 100–150W to deposit an Au or Ag conductive and thermally conductive layer to obtain a Ti-Au or Ti-Ag bilayer metal transition layer.

[0019] Furthermore, the thickness of the Ti adhesive layer is 10–20 nm, the thickness of the conductive and thermally conductive layer is 10–30 nm, and the thickness of the double-layer metal transition layer is 20–50 nm.

[0020] This application integrates a fully optimized process, including prestressed controlled precise exfoliation, low-temperature magnetron sputtering alloy layer deposition, and center-edge gradient differential bonding, to construct a highly efficient, stable, and reliable large-size flexible diamond heat dissipation structure fabrication system. This significantly enhances the application value and adaptability of diamond in the field of heat dissipation for high-power electronic devices, while also taking into account process feasibility, scalable production potential, and long-term reliability.

[0021] Among them, the pre-stress-controlled precision peeling process for diamond films can achieve the complete acquisition of large-size flexible diamond films without damage or stress concentration, preserving their smooth polished interface and intrinsic ultra-high thermal conductivity. It effectively avoids the problems of film damage, surface scratches and performance degradation caused by traditional peeling methods, laying a solid foundation for subsequent efficient bonding and heat conduction.

[0022] The low-temperature magnetron sputtering alloy layer deposition process can form a uniform, dense, and firmly bonded alloy transition layer in a low-temperature environment. This process avoids damage to the intrinsic properties of diamond caused by high temperatures, significantly reduces interfacial thermal resistance, and improves interfacial bonding. It also provides a stable pathway for rapid heat conduction, thus solving the problems of diamond performance degradation, weak alloy layer bonding, and numerous interfacial defects caused by traditional high-temperature coating.

[0023] Specifically, the low operating temperature throughout the low-temperature sputtering process avoids damage from diamond lattice distortion and graphitization, thus preserving its inherent properties. The deposited alloy layer has dense and uniform grains and a tight interface, reducing voids and thermal expansion mismatch, effectively lowering the interface thermal resistance. In addition, the sputtered alloy layer has excellent wettability and forms a stable interlocking bond with the upper and lower interfaces. Compared with the high-temperature coating, which is prone to cracking and has high internal stress, it can significantly weaken the residual stress at the interface. At the same time, the good film coating and stable interface interlocking can weaken the residual stress and improve the interface bonding strength and heat transfer stability.

[0024] The center-edge gradient integrated bonding process between diamond films and chips achieves a high-strength, low-stress, and low-resistivity bond by synergistic effects of interface cleaning, high-precision alignment, zoned temperature-controlled pressurization, and inert gas protection. This is further enhanced by a differentiated structural design, combining a double-layer transition layer of Ti-Au or Ti-Ag in the central strong bonding region with a buffer structure in the edge stress-relief region. This effectively avoids problems such as interface contamination, oxidation, warpage, and detachment, fully leveraging the ultra-high thermal conductivity of diamond to achieve rapid heat dissipation and uniform diffusion in electronic devices.

[0025] This application not only solves many problems in the fabrication of traditional diamond heat dissipation structures, such as thin film damage, weak adhesion, high thermal resistance, easy oxidation failure, and poor environmental adaptability, but also optimizes the compatibility and operability of the entire process, reducing the difficulty and cost of large-scale production. Ultimately, the resulting diamond heat dissipation structure possesses lower and more stable interfacial thermal resistance, higher heat transfer efficiency, stronger mechanical stability, and environmental tolerance. It can effectively alleviate the heat accumulation problem during long-term operation of high-power electronic devices, slow down device performance degradation and aging, extend the lifespan of electronic devices, and improve device operational stability and safety. This broadens the application scope of diamond in high-power electronics, optoelectronics, and microwave devices, better meeting the needs of various electronic devices for higher power, miniaturization, flexibility, and longer lifespan, and providing reliable technical support for the research and industrialization of next-generation high-efficiency heat dissipation devices.

[0026] Compared with the prior art, this application has the following beneficial effects: 1. By applying a directional prestress field to the diamond film growth interface and combining it with a non-contact stress uniform release mechanism, complete and non-destructive peeling of large-size flexible diamond films can be achieved. This effectively avoids substrate scratches, functional layer damage and residual interface stress, ensuring interface cleanliness and bonding strength, and significantly improving device structural stability and heat dissipation reliability.

[0027] 2. This application employs an ultra-low temperature magnetron sputtering process, combined with specific sputtering power ratios, working gas pressures, gradient layer thickness ratios, and alloy composition ratios, to prepare a gradient structure indium gallium aluminum alloy ternary alloy transition layer on the surface of a diamond thin film. This low-temperature process can completely avoid thermal damage to the diamond structure caused by high temperatures, while simultaneously forming a gradient interface structure that significantly reduces interfacial thermal resistance, which is fundamentally different from traditional high-temperature coating and single-layer alloy layer processes.

[0028] 3. This application features a unique partitioned bonding mode with a central strong bonding zone and an edge stress-relieving zone, coupled with an integrated process of partitioned temperature control, graded pressurization, and inert atmosphere synergistic protection. This effectively eliminates interfacial thermal stress and warpage deformation, breaking through the technical bottleneck of traditional uniform bonding across the entire region. Attached Figure Description

[0029] Figure 1 This is a schematic diagram illustrating the use of PI tape to peel a large-size flexible diamond film from a substrate, as described in this application.

[0030] Figure 2 This is a schematic diagram of the indium gallium aluminum alloy layer deposition process of this application.

[0031] Figure 3 This is a schematic diagram of the bonding process between large-size flexible diamond and chip in this application.

[0032] Labeling Explanation: 1. Substrate; 2. Gradient Composite Layer; 3. Diamond Film to be Peeled Off; 4. PI Tape; 5. Large-size Flexible Diamond Film; 6. Indium Gallium Aluminum Alloy Layer; 7. Diamond Composite Film; 8. Chip; 9. Double-layer Metal Transition Layer; 10. Buffer Structure. Detailed Implementation

[0033] This application provides a method for large-size flexible diamond peeling and bonding for device heat dissipation. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following provides a more detailed description. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] This application provides a method for large-size flexible diamond peeling and bonding for device heat dissipation, including the following steps: Step 1: Pre-stress gradient release non-destructive exfoliation of diamond films: Step 1 (1): Substrate 1 (preferably a single-crystal silicon wafer) is ultrasonically cleaned with acetone and anhydrous ethanol for 5-20 minutes each, and then dried with nitrogen gas for later use.

[0035] Step 1 (2): Preparation of gradient composite layer 2 by magnetron sputtering: Radio frequency magnetron sputtering is used, with SiO2 target as substrate and Ag, Ti, and Au metal targets as nanoparticle sources. The power is continuously and gradually varied from silicon to diamond: near silicon side: metal target power is relatively high → more and smaller nanoparticles; near diamond side: metal target power is relatively low → fewer and larger nanoparticles.

[0036] Sputtering temperature: Constant temperature control is adopted, and the temperature can be controlled within the range of room temperature to 200℃, preferably (120±10)℃. At this temperature, sputtered atoms have a moderate surface mobility, which can ensure that the SiO2 substrate film is dense and free of pinholes, and can precisely control the size of the nano-metal particles to be stable at 2-10nm, and uniformly dispersed without agglomeration; at the same time, it can effectively release the internal stress during the film deposition process, and avoid film warping and peeling during subsequent annealing and diamond deposition processes. It is perfectly adapted to the mass production requirements of 2-6 inch large-size substrates and has the best compatibility with the entire process flow of this solution.

[0037] Total film thickness: 300–600 nm.

[0038] Regarding the continuously gradient power from silicon to diamond: A four-target RF magnetron sputtering system is used, with Ag, Ti, and Au metal targets and a silica target independently installed at four sputtering targets, allowing independent control of the sputtering power of each target. The core control standard is that during co-sputtering, the sputtering power of the three metal targets maintains a synchronous linear gradient, and the power ratio of Ag:Ti:Au is maintained at (4.5-5.5):(2.5-3.5):(1.5-2.5) throughout the process, ensuring the uniformity of nanoparticle composition and the consistency of gradient distribution, and avoiding particle agglomeration and component segregation; the silica target maintains a constant power.

[0039] The near-silicon side refers to the side of the gradient composite layer 2 closest to the substrate 1. Near-diamond side refers to the side of the gradient composite layer 2 that is closer to the subsequently deposited diamond; It is important to note that the two are actually a continuous and gradual transition zone without a clear boundary, ensuring a continuous transition of stress and modulus.

[0040] Sputtering initiation: The total sputtering power of Ag, Ti, and Au metal targets is preferably 120–150W, while the sputtering power of SiO2 target remains constant at 70–90W throughout the process; Sputtering ends: The total sputtering power of Ag, Ti, and Au metal targets is preferably 20–40 W, while the sputtering power of SiO2 target remains constant at 70–90 W; Throughout the sputtering process, the total power of the metal target decreases linearly and continuously from 120–150W to 20–40W without any power abrupt changes, achieving a continuous gradient distribution of nano-metal particles from "numerous and small" to "few and large".

[0041] Low-temperature annealing and shaping: annealing at 350-450℃ for 20-45 minutes in a vacuum or argon atmosphere to stably precipitate nano-metal particles and make the film dense, forming a gradient composite layer 2 with modulus gradient, stress gradient, enhanced bonding force and buffering effect.

[0042] A SiO2 embedded nano-metal gradient layer, namely gradient composite layer 2, is formed directly in one step. The particle size of the metal particles ranges from 2 to 10 nm, and they are uniformly dispersed and do not agglomerate.

[0043] Lower limit of particle size: 2nm: If the particle size is <2nm, the stress dispersion effect of nanoparticles will be greatly reduced; Upper limit of particle size: 10nm: If the particle size is >10nm, it will cause a significant increase in the surface roughness of the film.

[0044] Step 1 (3): Depositing the diamond film to be peeled off 3: The substrate 1 with the gradient composite layer 2 is directly fed into a CVD equipment to deposit diamond. A large-sized diamond film 3 (diameter not less than 2 inches) to be peeled off is prepared on the gradient composite layer 2 using the MPCVD method to obtain the part to be peeled off.

[0045] SiO2 has stable chemical properties and strong adhesion to silicon substrates, and can uniformly bear interfacial stress. Embedded nano-metal particles can utilize the stress dispersion effect to avoid abrupt changes in interfacial bonding force, thus ensuring the feasibility of peeling from the material level.

[0046] Step 1 (4): Modify the interface by stepwise ultraviolet irradiation: Place the part to be peeled horizontally on the light-shielding platform. Using the geometric center of the part to be peeled as a reference, define 65-75% of the radial area as the central area and the remaining annular area on the outside as the edge area.

[0047] A circular light-shielding mask with central blocking and edge transparency is used to shield the part to be stripped, exposing only the edge area to ultraviolet radiation; the wavelength is 240–280 nm and the power is 20–30 mW / cm². 2 The edge area is irradiated with ultraviolet light for 5–8 minutes to improve the cross-linking degree and stress level of the edge interface.

[0048] The wavelength is further preferably 250–260 nm; the most preferred wavelength is 254 nm.

[0049] Subsequently, the light-shielding mask was removed, and the entire area of ​​the part to be stripped was uniformly and weakly irradiated to create an internal stress gradient distribution with low central stress and high edge stress at the interface.

[0050] The weak irradiation parameters are: 240–280 nm, power 5–10 mW / cm². 2 Time: 1-2 minutes.

[0051] The wavelength of weak irradiation is further preferably 250–260 nm; most preferably 254 nm; the wavelength of weak irradiation is preferably the same as that of strong irradiation.

[0052] Then, through non-uniform zone temperature control, the temperature of the edge area is controlled at 80–100℃ and the temperature of the center area is controlled at 40–60℃ for 2–8 minutes, so as to release the high stress at the edge first and protect the central film layer from thermal damage.

[0053] The optimal processing time for non-uniform zone temperature control is 3-5 minutes to avoid process failure or film damage.

[0054] Step 1 (5): Select a high-temperature resistant PI tape 4 with a temperature resistance range of not less than 250℃ (thickness of 50-100μm, adhesion of 15-20N / 25mm). Slowly attach the adhesive side of the PI tape 4 to the non-growth side of the diamond film 3 to be peeled off. During the attachment process, gently wipe with a lint-free cloth under uniform pressure to ensure that the tape and the diamond film are completely attached without bubbles, wrinkles, or misalignment.

[0055] Step 1 (6): After bonding, place the irradiated part to be peeled with PI tape 4 on it horizontally. Use a precision constant force traction device and an angle-adjustable clamping fixture to fix the base and clamp the end of PI tape 4. The tension sensor is used to control the output of constant tension to avoid instantaneous impact and tension fluctuations. Peeling starts with a small angle traction. During the peeling process, the mechanism continuously and smoothly adjusts the traction angle. The overall dynamic change is within the range of 15°-45°. With the straight uniform speed traction, the tension deviation is corrected in real time and the interface stress is released. Relying on constant force stable traction and variable angle coordinated peeling, the film layer is separated smoothly without impact and cracks, avoiding instantaneous excessive force or tension deviation, and achieving smooth separation of the film layer without impact and cracks.

[0056] The assembly obtained at this point, which includes PI tape 4 and diamond film 3 to be peeled off, is defined as the part to be separated.

[0057] Step 1 (7): After peeling off the part to be separated, gently blow away any small amount of silicon debris that may remain on the surface of the diamond film with a nitrogen gun, and then immediately perform the adhesive removal operation in a Class 100 clean environment.

[0058] Specifically, the tape to be separated is placed flat with the tape side facing up in a solvent-resistant container made of polytetrafluoroethylene (PTFE). Sufficient analytical grade N-methylpyrrolidone (NMP) solution is added to completely submerge the tape. The container is then sealed and placed in a constant temperature water bath at 80-90℃ for 30-60 minutes until the PI tape 4 is fully swollen and naturally separates from the diamond film 3 to be peeled off. The diamond film 3 is carefully removed using clean PTFE tweezers and sequentially transferred to acetone and anhydrous ethanol for ultrasonic cleaning at room temperature for 1-10 minutes each to thoroughly remove residual NMP solvent and PI tape fragments. Finally, high-purity nitrogen (99.999%) is slowly blown dry along a direction parallel to the film surface to obtain a large-size flexible diamond film 5 with a clean surface and no mechanical damage.

[0059] Then it proceeds to the subsequent coating process.

[0060] The above steps ensure that the interface between the large-size flexible diamond film 5 and the gradient composite layer 2 remains smooth and polished (surface roughness Ra≤0.5μm), with a flat surface, no damage, no scratches, no impurities, and no wrinkles or stress.

[0061] This method is based on the interfacial stress gradient release mechanism. The materials and processes are compatible with conventional semiconductor manufacturing processes, making it highly feasible and completely solving the problems of easy breakage, wrinkling, and stress concentration caused by traditional mechanical peeling.

[0062] A schematic diagram illustrating the process of smoothly peeling a large-size flexible diamond film 5 from the substrate 1 using PI tape 4 is shown below. Figure 1 .

[0063] Step 2: Deposition of the low-temperature alloy layer: Reference Figure 2 The large-size flexible diamond film 5 is fixed on the sample holder of the PVD coating equipment using a special clamp, ensuring that the smooth polished surface of the large-size flexible diamond film 5 (the side originally attached to the gradient composite layer 2) faces upwards and the surface is flat and wrinkle-free. The clamping force of the clamp is moderate (0.05-0.1MPa) to avoid the film being damaged due to excessive tightness or the large-size flexible diamond film 5 shifting during the coating process due to excessive looseness.

[0064] Close the coating equipment chamber and start the vacuum pump to evacuate the chamber to a vacuum level of 1×10⁻⁶. -4 Pa or above (high vacuum environment), while heating the sample holder to 80-150℃ (low temperature conditions), and holding for 5-20 minutes to remove residual moisture and trace impurities from the film surface.

[0065] Magnetron sputtering was employed, using an indium gallium aluminum alloy target [indium:gallium:aluminum molar ratio of (5.5-6.5):(2.5-3.5):(0.5-1.5)] as the sputtering source. The sputtering power was controlled at 80-120W, the distance between the target and the diamond film was 8-12cm, the sputtering gas (argon) flow rate was 20-30sccm, and the deposition time was 10-30min. During the deposition process, the chamber temperature was kept stable at 80-150℃ to avoid temperature fluctuations that could lead to uneven alloy layer thickness.

[0066] After deposition, the sputtering power supply is turned off, the chamber is kept in a vacuum state, and the chamber is allowed to cool naturally to room temperature before the chamber is opened and the sample is taken out to obtain a diamond composite film 7 with an indium gallium aluminum alloy layer 6 deposited on the surface.

[0067] The thickness of the indium gallium aluminum alloy layer 6 is controlled between 50-200 nm, and the surface is uniform, dense, free of pinholes and flaking. The adhesion to the surface of the large-size flexible diamond film 5 is not less than 15 N / cm. 2 .

[0068] Step 3: Center-edge gradient bonding of diamond composite film 7 and chip 8: Step 3 (1): Clean the diamond composite film 7 and the electronic device chip 8 with anhydrous ethanol for 5-8 minutes to remove surface impurities and oxide layer, and then air dry for later use.

[0069] Step 3 (2): Divide the bonding interface into a central strong bonding area and an edge stress-relieving area. The bonding interface is uniformly rigidly partitioned based on the geometric center of chip 8. The central strong bonding area is the circular core area of ​​65-75% of the radial dimension of chip 8, and the remaining outer annular area is designated as the edge stress-relieving area.

[0070] Step 3 (3): A Ti-Au or Ti-Ag bilayer metal transition layer 9 is prepared by magnetron sputtering only on the surface of the strong bonding area in the center of the diamond composite film 7 corresponding to the chip 8. No hard metal transition layer is plated in the edge stress relief area, so as to form a gradient bonding structure with high bonding strength in the center and flexible stress relief at the edge.

[0071] The specific preparation method includes the following steps: According to the bonding partition matching circular metal mask, magnetron sputtering is performed only on the surface of the strong bonding area in the center of the chip 8 corresponding to the diamond composite film 7.

[0072] The diamond composite film 7 was placed as a substrate in the magnetron sputtering cavity, and the vacuum level was evacuated to ≤5×10⁻⁶. -4 Pa, introduce high-purity argon gas with a purity of 99.999%, and adjust the gas pressure in the chamber to 0.3–0.5 Pa.

[0073] First, a pure Ti target is sputtered with a DC power of 80–120W to deposit a Ti binder layer with a thickness of 10–20 nm, so that Ti forms stable chemical bonds with the diamond surface in the diamond composite film 7. Then, an Au or Ag target is sputtered with a DC power of 100–150W to deposit an Au or Ag conductive and thermally conductive layer with a thickness of 10–30 nm.

[0074] The total double-layer thickness is controlled within 20–50 nm, and the film uniformity error is ≤5%.

[0075] Ti can form stable chemical bonds with diamond to improve adhesion, while Au and Ag have excellent thermal and electrical conductivity, ensuring high-strength bonding and efficient heat conduction in the core heat dissipation area.

[0076] Step 3 (4): The edge stress relief area of ​​the diamond composite film 7 corresponding to the chip 8 adopts a buffer structure 10 (thickness 10–30 nm) of Cr+ nano oxide layer.

[0077] The preparation method includes the following steps: By using a mask to shield the central strong bonding region of the diamond composite film 7 corresponding to the chip 8, only the edge stress-relief region of the diamond composite film 7 corresponding to the chip 8 is coated. First, a layer of metallic Cr is deposited by magnetron sputtering, with the film thickness controlled between 5 and 15 nm. The thermal expansion coefficient of Cr material has excellent compatibility with diamond, ensuring the bonding strength of the interface.

[0078] Then, by using low-temperature plasma oxidation or mild ultraviolet oxidation, a dense nano-oxide layer with a thickness of 5–15 nm is generated in situ on the Cr surface, and the thickness of the overall buffer structure 10 is finally stabilized at 10–30 nm.

[0079] Regarding the "mild" in the mild UV oxidation method: it means that only a dense nano oxide layer of 5–15 nm thick is generated in situ on the surface of the Cr metal. The oxide layer does not penetrate the Cr metal substrate. After oxidation, the thickness of the remaining intact Cr metal substrate is ≥5 nm, and the total thickness of the final overall buffer structure 10 is stable at 10–30 nm.

[0080] This nano-oxide layer possesses a porous micro / nano structure, which can effectively absorb and buffer the thermal mismatch stress of the diamond-chip 8-bond, forming a gradient bonding system with high-strength central bonding and mildly relieved edge stress. The thermal expansion coefficient of Cr is highly compatible with that of diamond, and the nano-oxide layer can absorb interfacial mismatch stress. All materials selected are conventional materials for microelectronic bonding, ensuring high process compatibility and feasibility.

[0081] The diamond composite film 7, which is prepared by magnetron sputtering of a Ti-Au or Ti-Ag bilayer metal transition layer 9 on the surface of the central strong bonding region and has a buffer structure 10 in the edge stress-relieving region, is defined as the composite material to be bonded.

[0082] Step 3 (5): Use a high-precision positioning fixture (positioning accuracy ≤ 30 μm) to accurately align the bonding compound with the heat dissipation area of ​​the electronic device chip 8, ensuring that the alignment deviation does not exceed 50 μm and that the heat dissipation path is unobstructed.

[0083] The aligned sample is placed into the heating and pressurizing bonding equipment. The heating and pressurizing bonding equipment with independent temperature control in the partition is used. The platform has two sets of independent heating and temperature measurement modules built into the center and the edge, which can achieve differentiated temperature control of different areas of the chip at the same time.

[0084] The central strong bonding zone is stably maintained at 250-300℃ to achieve high-temperature strong bonding, while the edge stress-relieving zone is kept constant at 150-200℃ to form low-temperature weak bonding. A continuous temperature field transition zone is set between the center and the edge, with the temperature gradually changing radially without abrupt changes to avoid local thermal stress concentration. A total bonding pressure of 0.3–0.5MPa is applied throughout the process, and the temperature and pressure are maintained for 10–20 minutes. Nitrogen gas is continuously introduced into the cavity at a flow rate of 15–20 sccm to isolate oxygen and prevent high-temperature oxidation of the alloy layer and the chip surface. By matching the zoned temperature control, temperature field transition, and gradient bonding process, both interfacial bonding strength and edge stress relief are considered.

[0085] Regarding the continuous temperature transition zone: The continuous temperature transition zone is a coaxial annular band within 65%-75% of the radial dimension of the chip 8. The temperature gradually changes linearly, continuously and uniformly from the set value of the central strong bonding zone to the set value of the edge stress-relieving zone along the radial direction. The temperature change rate is controlled at 20–40℃ / mm. The temperature change within any 1mm length does not exceed 50℃, and the temperature deviation on the same radius circumference is ≤5℃. There are no sudden temperature changes or breaks, effectively avoiding local thermal stress concentration at the bonding interface.

[0086] After bonding is completed, the heating and pressurization systems are turned off, and a nitrogen protective atmosphere is maintained throughout the process to avoid interface oxidation and thermal shock during the cooling stage. The sample is slowly and naturally cooled to room temperature by the chamber before being taken out to obtain the finished product.

[0087] Based on the aforementioned zoned differentiated temperature control, gradient pressure, and synergistic design of strong central metal bonding and edge buffering, the interface thermal shrinkage rate transitions smoothly radially during cooling. The strong central bonding zone forms a dense metallurgical bond through high-temperature bonding, achieving high strength retention and low contact thermal resistance. The edge stress-relieving zone relies on low-temperature weak bonding and the flexible nano-buffer structure to dissipate heat mismatch stress. The bonding strength and stress state of the central and edge interfaces change continuously and gradually, without obvious interface abrupt changes or stress concentration defects. No additional testing data is required. The gradient bonding interface can be stably formed through the combination of structural layer design and zoned bonding process. From the perspective of preparation principle and structural adaptability, this ensures the differentiated interface effect of high central bonding reliability and long-term edge buffering and crack resistance.

[0088] It structurally solves the problems of warping, bulging, and detachment in traditional uniform bonding, and significantly improves bonding strength and long-term reliability.

[0089] A schematic diagram of the center-edge partitioned gradient bonding structure between the large-size flexible diamond film 5 and the chip 8 is shown below. Figure 3 .

[0090] The present application will be further described below through specific embodiments.

[0091] Example 1 This embodiment provides a method for large-size flexible diamond peeling and bonding for device heat dissipation, including the following steps: Step 1: Pre-stress gradient release non-destructive peeling of large-size flexible diamond film 5: Step 1 (1): Clean the monocrystalline silicon wafer sequentially with acetone and anhydrous ethanol using ultrasonic cleaning for 10 minutes each, then dry it with nitrogen gas for later use.

[0092] Step 1 (2): Preparation of gradient composite layer 2 by magnetron sputtering: Radio frequency magnetron sputtering was employed, using a SiO2 target as the substrate and Ag, Ti, and Au metal targets as the nanoparticle source. The power was continuously gradient from the silicon to the diamond surface: near the silicon side: high metal power → more and smaller nanoparticles; near the diamond side: low metal power → fewer and larger nanoparticles. Sputtering temperature: 120℃; total film thickness: 450nm.

[0093] Specifically, a four-target RF magnetron sputtering system is used, with Ag, Ti, and Au metal targets and a silicon dioxide target installed independently at four sputtering target positions, and the sputtering power of each target material is independently controlled. During co-sputtering, the sputtering power of the three metal targets is kept synchronously and linearly varied, and the power ratio of Ag:Ti:Au is maintained at 5:3:2 throughout the process, while the silicon dioxide target uses a constant power.

[0094] The silicon-near side refers to the side of the gradient composite layer 2 closest to the substrate 1; the diamond-near side refers to the side of the gradient composite layer 2 closest to the subsequently deposited diamond.

[0095] Sputtering begins: The total sputtering power of Ag, Ti, and Au metal targets is 140W, while the sputtering power of the SiO2 target remains constant at 80W throughout the process. Sputtering complete: The total sputtering power of Ag, Ti, and Au metal targets is 30W, while the sputtering power of the SiO2 target remains constant at 80W.

[0096] Throughout the sputtering process, the total power of the metal target decreased linearly and continuously from 140W to 30W, without any power abrupt changes.

[0097] Low-temperature annealing and shaping: annealing at 400℃ for 30 minutes in a vacuum atmosphere allows for the stable precipitation of nano-metal particles and the formation of a dense film, resulting in a gradient composite layer 2 with modulus gradient, stress gradient, enhanced bonding force, and buffering effect.

[0098] The particle size of the metal particles ranges from 2 to 10 nm.

[0099] Step 1 (3): Depositing a diamond film: The substrate 1 with the gradient composite layer 2 is directly fed into a CVD equipment to deposit diamond. A large-sized diamond film 3 (diameter not less than 2 inches) to be peeled off is prepared on the gradient composite layer 2 using MPCVD, thus obtaining the part to be peeled off.

[0100] Step 1 (4): Modify the interface by stepwise ultraviolet irradiation: Place the part to be peeled horizontally on the light-shielding platform. Using the geometric center of the part to be peeled as a reference, 70% of the radial area is designated as the central area, and the remaining annular area on the outside is designated as the edge area.

[0101] A circular light-shielding mask with central blocking and edge transparency is used to shield the part to be stripped, exposing only the edge area to ultraviolet radiation; a wavelength of 254nm and a power of 25mW / cm² are used. 2 The edge area is irradiated with ultraviolet light for 5–8 minutes to improve the cross-linking degree and stress level of the edge interface.

[0102] The light-shielding mask was then removed, and the wavelength was 254nm with a power of 8W / cm. 2Under certain conditions, the entire area of ​​the part to be stripped is subjected to uniform weak irradiation for 1–2 minutes to create an internal stress gradient distribution with low central stress and high edge stress at the interface.

[0103] Then, through non-uniform zone temperature control, the temperature of the edge area is controlled at 90℃ and the temperature of the center area is controlled at 50℃ for 4 minutes, which prioritizes the release of high stress at the edge and protects the central film layer from thermal damage.

[0104] Step 1 (5): Select a high-temperature resistant PI tape 4 with a temperature resistance range of not less than 250℃ (thickness of 50-100μm, adhesion of 15-20N / 25mm). Slowly attach the adhesive side of the PI tape 4 to the non-growth side of the diamond film 3 to be peeled off. During the attachment process, gently wipe with a lint-free cloth under uniform pressure to ensure that the tape and the diamond film are completely attached without bubbles, wrinkles, or misalignment.

[0105] Step 1 (6): After bonding, place the irradiated part to be peeled horizontally. Use a precision constant force traction device and an angle-adjustable clamping fixture to fix the base and clamp the four ends of the PI tape. The tension sensor is used to control the output of constant tension in a closed loop to avoid instantaneous impact and tension fluctuations. Peeling starts with a small angle traction. During the peeling process, the mechanism continuously and smoothly adjusts the traction angle. The overall dynamic change is within the range of 15°-45°. With the straight uniform speed traction, the tension deviation is corrected in real time and the interface stress is released. Relying on constant force stable traction and variable angle coordinated peeling, the film layer is separated smoothly without impact or cracks, avoiding instantaneous excessive force or tension deviation, and achieving smooth separation of the film layer without impact or cracks.

[0106] The assembly obtained at this point, which includes PI tape 4 and diamond film 3 to be peeled off, is defined as the part to be separated.

[0107] Step 1 (7): After peeling, gently blow away any remaining silicon debris on the surface of the part to be separated using a nitrogen gun.

[0108] Place the PI tape 4, with its adhesive side facing up, flat in a solvent-resistant PTFE container. Add sufficient analytical grade N-methylpyrrolidone (NMP) solution to completely submerge the PI tape 4. Seal the container and place it in an 85°C constant temperature water bath for 45 minutes until the PI tape 4 is fully swollen and naturally separates from the diamond film 3 to be peeled off. Carefully remove the diamond film 3 to be peeled off using clean PTFE tweezers and transfer it sequentially to acetone and anhydrous ethanol for ultrasonic cleaning at room temperature for 5 minutes each to thoroughly remove residual NMP solvent and PI tape fragments from the surface. Finally, slowly dry the film with 99.999% pure nitrogen gas in a direction parallel to the film surface to obtain a large-size flexible diamond film 5 with a clean surface and no mechanical damage.

[0109] Ensure that the interface between the large-size flexible diamond film 5 and the gradient composite layer 2 remains smooth and polished (surface roughness Ra≤0.5μm), with a flat surface, free from damage, scratches, impurities, and wrinkles.

[0110] Step 2: Deposition of the low-temperature alloy layer: The large-size flexible diamond film 5, after the PI tape 4 has been peeled off, is fixed on the sample holder of the PVD coating equipment using a special clamp. This ensures that the smooth polished surface of the large-size flexible diamond film 5 (the side originally attached to the gradient composite layer 2) faces upwards, the surface is flat and wrinkle-free, and the clamping force of the clamp is moderate (0.05-0.1MPa). This avoids excessive clamping which could cause film damage, or excessive loose clamping which could cause the large-size flexible diamond film 5 to shift during the coating process.

[0111] Close the coating equipment chamber and start the vacuum pump to evacuate the chamber to a vacuum level of 1×10⁻⁶. -4 Pa (high vacuum environment), while the sample holder temperature is heated to 100℃ (low temperature condition) and held for 10 min to remove residual moisture and trace impurities on the film surface.

[0112] The method of magnetron sputtering was adopted, with an indium gallium aluminum alloy target (indium:gallium:aluminum molar ratio of 6:3:1) as the sputtering source. The sputtering power was controlled at 100W, the distance between the target and the diamond film was 10cm, the sputtering gas (argon) flow rate was 25sccm, and the deposition time was 20min. During the deposition process, the chamber temperature was kept stable at 100℃ to avoid uneven alloy layer thickness caused by temperature fluctuations.

[0113] After deposition, the sputtering power supply is turned off, the chamber is kept in a vacuum state, and the chamber is allowed to cool naturally to room temperature before the chamber is opened and the sample is taken out to obtain a diamond composite film 7 with an indium gallium aluminum alloy layer 6 deposited on the surface.

[0114] The indium gallium aluminum alloy layer 6 is 100 nm thick, with a uniform, dense surface free of pinholes and peeling, and its adhesion to the diamond film surface is no less than 15 N / cm. 2 .

[0115] Step 3: Center-edge gradient bonding of diamond composite film 7 and chip 8: Step 3 (1): Clean the diamond composite film 7 and the electronic device chip 8 with anhydrous ethanol for 6 minutes to remove surface impurities and oxide layer, and then air dry for later use.

[0116] Step 3 (2): Divide the bonding interface into a central strong bonding area and an edge stress-relieving area. The bonding interface is uniformly hard partitioned based on the geometric center of chip 8. The central strong bonding area is the 70% circular core area within the radial dimension of chip 8, and the remaining outer annular area is designated as the edge stress-relieving area.

[0117] Step 3 (3): A Ti-Au double metal transition layer is prepared only on the surface of the strong bonding area in the center of the diamond composite film 7 corresponding to the chip 8 by magnetron sputtering. No hard metal transition layer is plated in the edge stress relief area, so as to form a gradient bonding structure with high bonding strength in the center and flexible stress relief at the edge.

[0118] The specific preparation method includes the following steps: According to the bonding partition matching circular metal mask, magnetron sputtering is performed only on the surface of the strong bonding area in the center of the chip 8 corresponding to the diamond composite film 7.

[0119] The diamond composite film 7 was placed as a substrate in the magnetron sputtering cavity, and the vacuum level was evacuated to ≤5×10⁻⁶. -4 Pa, introduce high-purity argon gas with a purity of 99.999%, and adjust the gas pressure in the chamber to 0.4 Pa.

[0120] First, a pure Ti target was sputtered with a DC power of 100W to deposit a Ti binder layer with a thickness of 15nm, so that Ti and the diamond surface in the diamond composite film 7 could form stable chemical bonds. Then, an Au target was sputtered with a DC power of 120W to deposit an Au conductive and thermally conductive layer with a thickness of 20nm.

[0121] The total thickness of the double-layer metal transition layer 9 is controlled at 35nm, and the film uniformity error is ≤5%.

[0122] Step 3 (4): The edge stress relief area of ​​the diamond composite film 7 corresponding to the chip 8 adopts a buffer structure 10 of Cr + nano oxide layer.

[0123] The preparation method includes the following steps: The strong bonding region at the center of the diamond composite film 7 corresponding to the chip 8 is blocked by a mask, and only the stress-relieving region at the edge of the diamond composite film 7 corresponding to the chip 8 is coated. First, a layer of metal Cr is deposited by magnetron sputtering, and the film thickness is controlled at 10nm.

[0124] Then, a dense nano-oxide layer with a thickness of 10 nm was generated in situ on the Cr surface using a mild ultraviolet oxidation method, and the overall buffer structure 10 thickness was finally stabilized at 20 nm.

[0125] The diamond composite film 7, which is prepared by magnetron sputtering of the central strong bonding region surface as a Ti-Au bilayer metal transition layer 9 and has a buffer structure 10 in the edge stress-relieving region, is defined as the composite material to be bonded.

[0126] Step 3 (5): Use a high-precision positioning fixture (positioning accuracy ≤ 30 μm) to accurately align the bonding compound with the heat dissipation area of ​​the electronic device chip 8, ensuring that the alignment deviation does not exceed 50 μm and that the heat dissipation path is unobstructed.

[0127] The aligned sample is placed into the heating and pressurizing bonding equipment. The heating and pressurizing bonding equipment with independent temperature control in the partition is used. The platform has two sets of independent heating and temperature measurement modules built into the center and the edge, which can achieve differentiated temperature control of different areas of the chip at the same time.

[0128] The central strong bonding zone is stably maintained at 280℃ to achieve high-temperature strong bonding, while the edge stress-relieving zone is kept constant at 180℃ to form low-temperature weak bonding. A continuous temperature field transition zone is set between the center and the edge, with the temperature gradually changing radially without abrupt changes or faults, avoiding local thermal stress concentration. A total bonding pressure of 0.4MPa is applied throughout the process, and the temperature and pressure are maintained for 15 minutes. Nitrogen gas is continuously introduced into the cavity at a flow rate of 18sccm to isolate oxygen.

[0129] Regarding the continuous temperature transition zone: The continuous temperature transition zone is a coaxial annular band covering 65%-75% of the radial dimension of the chip 8. The temperature gradually and linearly changes from the set value in the central strong bonding area to the set value in the edge stress-relief area along the radial direction, with the temperature change rate controlled at 20–40℃ / mm. The temperature change within any 1mm length does not exceed 50℃, and the temperature deviation on the same radius circumference is ≤5℃. There are no sudden temperature changes or breaks, effectively avoiding local thermal stress concentration at the bonding interface. After bonding is completed, the heating and pressurization systems are turned off, and a nitrogen protective atmosphere is maintained throughout the process to avoid interface oxidation and thermal shock during the cooling stage. The sample is slowly and naturally cooled to room temperature by the chamber before being removed to obtain the finished product.

[0130] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of this application.

Claims

1. A method for large-size flexible diamond peeling and bonding for device heat dissipation, characterized in that, Includes the following steps: A gradient composite layer (2) is generated on a substrate (1), and a diamond film (3) to be peeled off is deposited on the gradient composite layer (2) to obtain the part to be peeled off. The interface of the part to be stripped was modified by stepwise ultraviolet irradiation in a partitioned manner; Separate the diamond film (3) to be peeled from the gradient composite layer (2) to obtain a large-size flexible diamond film (5); An alloy layer is generated on the smooth polished surface of a large-size flexible diamond film (5) to obtain a diamond composite film (7); The bonding interface is divided with the geometric center of the chip (8) as the reference. The central strong bonding area is the circular core area of ​​65-75% of the radial dimension of the chip (8), and the remaining outer annular area is the edge stress relief area. A Ti-Au or Ti-Ag bilayer metal transition layer (9) is sputtered on the surface of the strong bonding region at the center of the chip (8) corresponding to the diamond composite film (7); A buffer structure (10) is provided in the stress-relieving area at the edge of the chip (8) corresponding to the diamond composite film (7); the buffer structure (10) includes a metal Cr bottom layer and a nano oxide layer; The diamond composite film (7) with a double-layer metal transition layer (9) and a buffer structure (10) on its surface is defined as the bonding compound to be bonded; The bonding compound is precisely aligned with the heat dissipation area of ​​the chip (8), with an alignment deviation of no more than 50 μm; The bonding temperature in the central strong bonding zone is 250-300℃, and the bonding temperature in the edge stress-relieving zone is 150-200℃. A continuous temperature field transition zone is set between the center and the edge. The bonding pressure is 0.3-0.5MPa, and the temperature and pressure are maintained for 10-20 minutes to complete the bonding.

2. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 1, characterized in that, The provision of a buffer structure (10) in the stress-relief region at the edge of the diamond composite film (7) corresponding to the chip (8) includes: sputtering the metal Cr underlayer in the stress-relief region at the edge of the diamond composite film (7) corresponding to the chip (8); and then using plasma oxidation or ultraviolet oxidation to generate the nano oxide layer in situ on the metal Cr underlayer. The thickness of the buffer structure (10) is 10-30 nm.

3. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 1, characterized in that, The stepwise ultraviolet irradiation of the part to be peeled to modify the interface includes: taking the geometric center of the part to be peeled as the reference, 65-75% of the radial area is defined as the central area, and the remaining annular area on the outside is defined as the edge area. The edge region has a wavelength of 240–280 nm and a power of 20–30 mW / cm. 2 Under these conditions, subject to strong radiation for 5–8 minutes; Then, the entire area of ​​the component to be stripped is subjected to a wavelength of 240–280 nm and a power of 5–10 mW / cm. 2 Under these conditions, perform weak irradiation for 1-2 minutes; The edge area is then treated at 80-100℃ and the center area at 40-60℃.

4. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 1, characterized in that, The separation of the diamond film (3) to be peeled from the gradient composite layer (2) of the part to be peeled includes: Apply the tape to the non-growth surface of the diamond film (3) to be peeled off; The tape end is clamped and pulled at a constant tension and small angle. During the peeling process, the pulling angle is continuously and gently adjusted, and the overall dynamic change is within the range of 15°-45°. Combined with the straight and uniform speed traction, separation is achieved. The PI tape (4) was separated from the diamond film (3) to be peeled off by a chemical solution method to obtain a large-size flexible diamond film (5).

5. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 1, characterized in that, The gradient composite layer (2) is formed by magnetron sputtering of SiO2, Ag, Ti and Au.

6. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 1, characterized in that, The alloy layer includes an indium gallium aluminum alloy layer (6).

7. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 6, characterized in that, The formation of the indium gallium aluminum alloy layer (6) includes: using an indium gallium aluminum alloy target as a sputtering source, sputtering power of 80-120W, distance between the target and the diamond film of 8-12cm, sputtering gas flow rate of 20-30sccm, deposition time of 10-30min, and chamber temperature of 80-150℃ during deposition.

8. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 7, characterized in that, The thickness of the indium gallium aluminum alloy layer (6) is 50-200 nm; The bonding force between the indium gallium aluminum alloy layer (6) and the diamond film surface is not less than 15 N / cm. 2 .

9. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 1, characterized in that, The preparation of a Ti-Au or Ti-Ag bilayer metal transition layer (9) by sputtering on the surface of the strongly bonded region at the center of the diamond composite film (7) corresponding to the chip (8) includes: The diamond composite film (7) is used as a substrate, and a pure Ti target is sputtered with a DC power of 80–120W to deposit a Ti adhesive layer on the surface of the strong bonding area in the center of the chip (8) corresponding to the diamond composite film (7). Then, sputter Au or Ag targets with DC power of 100–150W to deposit Au or Ag conductive and thermally conductive layers to obtain Ti-Au or Ti-Ag bilayer metal transition layers (9).

10. The method for large-size flexible diamond peeling and bonding for device heat dissipation according to claim 9, characterized in that, The thickness of the Ti adhesive layer is 10–20 nm, the thickness of the conductive and thermally conductive layer is 10–30 nm, and the thickness of the double-layer metal transition layer (9) is 20–50 nm.

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