Diamond through hole metallization interconnection substrate and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductor advanced packaging and three-dimensional integrated interconnection, and particularly relates to a diamond through hole metallization interconnection substrate and a preparation method thereof. A diamond through hole metallization interconnection substrate comprises a diamond substrate and a metallization interconnection layer filled in a diamond substrate through hole. The metallization interconnection layer comprises Fe, Ni and one or more elements of Cr, Co, Mo, Mn and Cu. The diamond through hole metallization interconnection substrate can meet multiple requirements of thermal matching, reliability and electrical performance.

Description

Technical Field

[0001] This invention belongs to the field of advanced semiconductor packaging and three-dimensional integrated interconnect technology, specifically relating to a diamond through-hole metallized interconnect substrate and its preparation method. Background Technology

[0002] As chips rapidly evolve towards higher frequencies, higher power, and higher heat flux densities, the thermal management capabilities of the packaging substrate and the reliability of interconnects have become critical performance evaluation criteria. Diamond, with its ultra-high thermal conductivity and low coefficient of thermal expansion, has become an ideal substrate material for solving the challenges of high heat flux density packaging. However, when metal interconnect structures are filled into diamond vias, temperature fluctuations during the packaging process and chip operation can trigger severe interfacial thermal stress, leading to cracking of the via metal layer and delamination from the diamond substrate, thus disrupting the interconnect pathways. Poor wettability between the metal and the inner wall of the diamond via results in insufficient interfacial adhesion after sintering, making it difficult to meet long-term usage requirements. Poor oxidation resistance, limited mechanical properties, and low conductivity also make it impossible to simultaneously meet the multiple requirements of thermal matching, reliability, and electrical performance.

[0003] In summary, there is an urgent need for a diamond through-hole metallized interconnect substrate and its fabrication method. Summary of the Invention

[0004] The purpose of this invention is to provide a diamond through-hole metallized interconnect substrate and its fabrication method. The diamond through-hole metallized interconnect substrate provided by this invention addresses multiple requirements related to thermal matching, reliability, and electrical performance.

[0005] A first aspect of this invention is to provide a diamond through-hole metallized interconnect substrate, comprising a diamond substrate and a metallized interconnect layer filling the through-holes of the diamond substrate; the metallized interconnect layer comprises Fe, Ni, and one or more elements selected from Cr, Co, Mo, Mn, and Cu. This metallized interconnect layer, by introducing trace element nanoparticles of Cr, Co, Mo, Mn, and Cu, regulates the alloy's coefficient of thermal expansion, improves oxidation resistance, and enhances electrical conductivity and mechanical properties, thereby mitigating the problems of thermal expansion mismatch and limited performance between the metallized interconnect layer and the diamond substrate. This allows a diamond through-hole metallized interconnect substrate to meet multiple requirements of thermal matching, reliability, and electrical performance.

[0006] In some embodiments, the Fe content in the metallized interconnect layer is 61at%~66at%, and the Ni content is 33at%~38at%. This provides a low CTE substrate for the metallized interconnect layer, ensuring room for subsequent performance optimization, facilitating the matching of diamond performance, and balancing multiple requirements for thermal matching, reliability, and electrical performance.

[0007] In some embodiments, the total content of Cr, Co, Mo, Mn, and Cu in the metallized interconnect layer is 0.5 at% to 5%. This optimizes the alloy properties and facilitates sintering density.

[0008] In some embodiments, the metallized interconnect layer satisfies the following requirements: a coefficient of thermal expansion of 1.0 ppm / K to 1.3 ppm / K; and / or a resistivity ≤ 1.5 μΩ·m. This matches the thermal expansion of diamond and provides excellent conductivity, meeting the performance requirements of high-frequency, high-power packaging.

[0009] In some embodiments, the metallized interconnect layer is formed by sintering an alloy paste. This provides a process basis for stable and controllable component performance, avoiding problems such as poor density and numerous defects caused by non-paste sintering.

[0010] In some embodiments, the alloy slurry comprises the following components by mass fraction: 30% to 85% Fe and Ni, and one or more of Cr, Co, Mo, Mn, and Cu; 1% to 8% binder; 0.3% to 1.5% dispersant; and the remainder being organic solvent. This balances solid component content and flowability, adapts to through-hole filling processes, and ensures the density and performance of the interconnect layer after sintering.

[0011] In some embodiments, based on the total mass of Fe, Ni, Cr, Co, Mo, Mn, and Cu, the mass fractions of Cr, Co, Mo, Mn, and Cu are 0.5% to 5%. This enhances the stability of the performance optimization effect.

[0012] In some embodiments, Cr, Co, Mo, Mn, and Cu are nanoparticles with an average particle size of 50 nm to 200 nm. This improves their dispersibility and sintering activity in the slurry, facilitating the formation of a highly dense interconnect layer.

[0013] The second aspect of the present invention is to provide a method for preparing a diamond through-hole metallized interconnect substrate, comprising: step S01: pre-treating the diamond substrate, the pre-treating including through-hole cleaning and interface activation treatment; step S02: filling the pre-treated diamond substrate with alloy slurry; step S03: subjecting the filled diamond substrate to staged heat treatment and post-treatment to obtain a diamond through-hole metallized interconnect substrate.

[0014] Pre-treating the diamond substrate eliminates interfacial impurities and enhances the activity of the inner walls of the diamond vias, which is beneficial for improving interfacial adhesion after filling. Staged heat treatment systematically removes organic components, reducing porosity formation; the high specific surface area of ​​trace element nanoparticles in the alloy slurry promotes rapid formation of sintering necks, further increasing the density of the metal interconnect layer and improving the performance stability of the encapsulation substrate.

[0015] In some embodiments, the staged heat treatment includes a first-temperature drying process, a second-temperature debinding process, and a third-temperature sintering process. Through staged heat treatment, solvents are gradually removed, residues are eliminated, and sintering is promoted, mitigating cracks and porosity caused by single heating, and improving the density of the metal interconnect layer and the performance of the packaging substrate.

[0016] The beneficial effects of the present invention include at least one of the following: The alloy paste for filling diamond through-holes provided by this invention includes trace elements. On one hand, it can adjust the coefficient of thermal expansion of the sintered metal interconnect layer to match that of single-crystal diamond, significantly reducing the difference in thermal expansion between traditional metals and diamond substrates. This reduces interfacial thermal stress during the packaging process and long-term thermal cycling of the chip, effectively avoiding problems such as metal layer cracking and delamination from the diamond substrate, improving the thermal reliability of the interconnect structure, and extending the service life of high-frequency, high-power chips. On the other hand, the trace element nanoparticles have a high specific surface area, which can improve the density of the metal layer and reduce the porosity of thick film sintering. In addition, the introduction of Cu can reduce the resistivity of the metal layer. This gives the metal interconnect layer excellent electrical and thermal conductivity, ensuring low-loss transmission of high-frequency signals and assisting the diamond substrate in achieving efficient heat diffusion, adapting to the heat dissipation requirements of high heat flux density chips.

[0017] The slurry preparation and packaging substrate of this invention are compatible with existing semiconductor packaging production line equipment. The staged heat treatment process can avoid defects by precisely controlling the heating rate. The Fe, Ni, and trace elements such as Cr and Cu used are all commonly used industrial metals, which are widely available, cost-controllable, and more economical. Attached Figure Description

[0018] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A schematic diagram of a diamond through-hole metallized interconnect substrate structure provided by the present invention; Figure 2 A flowchart illustrating a method for fabricating a diamond through-hole metallized interconnect substrate provided by the present invention. Detailed Implementation

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] In the field of advanced semiconductor packaging and three-dimensional integrated interconnects, as chips rapidly develop towards higher frequencies, higher power, and higher heat flux densities, the thermal management capabilities of the packaging substrate and the reliability of interconnects have become core bottlenecks restricting performance breakthroughs. Although traditional through-silicon via (TSV) and through-glass via (TGV) technologies have achieved three-dimensional interconnects, the low thermal conductivity of silicon and glass makes it difficult to meet the high-efficiency heat dissipation requirements of high-power chips. At the same time, their coefficients of thermal expansion (CTE) differ from those of the core chip components, which can easily generate interfacial thermal stress under long-term thermal cycling, leading to interconnect structure detachment and decreased reliability.

[0023] Diamond, with its ultra-high thermal conductivity and low coefficient of thermal expansion, has become an ideal substrate material for solving the challenges of high heat flux density packaging, making through-diamond via (TDV) technology a research hotspot in the field of advanced packaging. However, when filling diamond vias with metal interconnect structures, existing technologies still face problems such as thermal expansion mismatch, sintering defects, and insufficient overall material properties.

[0024] In summary, this invention provides a diamond through-hole metallized interconnect substrate and its fabrication method, which addresses multiple requirements related to thermal matching, reliability, and electrical performance.

[0025] In a first aspect, the present invention provides a diamond through-hole metallized interconnect substrate, comprising a diamond substrate and a metallized interconnect layer filling the through-holes of the diamond substrate; the metallized interconnect layer comprises Fe, Ni, and one or more elements selected from Cr, Co, Mo, Mn and Cu.

[0026] In some embodiments, the Fe content in the metallized interconnect layer is 61at% to 66at, and the Ni content is 33at% to 38at.

[0027] In some embodiments, the amounts of iron and nickel metal powders in the metal powder can be adjusted according to the performance parameters of diamond. This Fe-Ni alloy ratio inherently possesses a low coefficient of thermal expansion, providing an ideal matrix for subsequent fine-tuning to approximate diamond levels using trace elements. This effectively avoids the problem of excessively high CTE (Coefficient of Thermal Expansion) due to imbalances in the main component ratio, making it difficult to match with diamond. Simultaneously, it helps improve the consistency of key properties such as conductivity and mechanical strength in the sintered metal interconnect layer. For example, adjusting the proportion of metals in the powder can effectively regulate the coefficient of thermal expansion and resistivity of the sintered metal. Specifically, the coefficient of thermal expansion of the sintered metal interconnect layer can be adjusted within the range of 1.0~1.3 ppm / K, and the resistivity can be adjusted to less than 1.5 μΩ·m.

[0028] In some embodiments, the total content of Cr, Co, Mo, Mn, and Cu in the metallized interconnect layer is 0.5 at% to 5 at%.

[0029] For example, those skilled in the art can select the mass fraction and average particle size of trace element particles as needed. This allows the CTE of the slurry to better match that of diamond and improves its oxidation resistance. It also reduces the probability of problems such as uneven alloy structure and increased resistivity. Within this range, trace element nanoparticles are beneficial for improving their dispersion uniformity in metal powders and reducing local performance fluctuations caused by agglomeration; at the same time, the high specific surface area can promote the rapid formation of "sintering necks" during sintering, reduce porosity, and improve the density and mechanical reliability of the metal interconnect layer.

[0030] In some embodiments, the metallized interconnect layer satisfies the following conditions: a coefficient of thermal expansion of 1.0 ppm / K to 1.3 ppm / K; and / or a resistivity ≤ 1.5 μΩ·m. This allows for better matching with diamond and improves the density and mechanical reliability of the metal interconnect layer.

[0031] In some embodiments, the metallized interconnect layer is formed by sintering an alloy paste.

[0032] In some embodiments, the alloy slurry comprises the following components by mass fraction: 30% to 85% of Fe and Ni and one or more of Cr, Co, Mo, Mn, and Cu; 1% to 8% of binder; 0.3% to 1.5% of dispersant; and the remainder being organic solvent.

[0033] In some embodiments, the alloy slurry for filling diamond through-holes may include a low-solids content alloy slurry: comprising 30%–45% solid components (one or more of Fe and Ni, and Cr, Co, Mo, Mn, and Cu), 4%–8% binder, and 0.3%–1.0% dispersant; the remainder being organic solvent. It may also include a medium-solids content alloy slurry: comprising 50%–65% solid components, 3%–6% binder, and 0.5%–1.5% dispersant; the remainder being organic solvent. Alternatively, it may include a high-solids content alloy slurry: comprising 70%–85% solid components, 1%–4% binder, and 0.5%–1.2% dispersant; the remainder being organic solvent. The low-solids content slurry is suitable for ultra-fine through-holes, avoiding the problem of poor flowability and inability to enter fine pores caused by the high-solids content slurry, ensuring full filling of ultra-fine through-holes. Medium-solids slurry is suitable for general applications and is compatible with common processes such as screen printing and coating. It has high density after sintering, balancing filling efficiency and performance, and is suitable for most conventional through-holes, improving process versatility. High-solids slurry reduces sintering shrinkage and has low porosity after sintering, with excellent electrical and thermal conductivity. It is suitable for vacuum pressing to fill deep through-holes, and can achieve the target thickness in one sintering, meeting the needs of scenarios requiring high density and high performance.

[0034] Among them, Cr can improve oxidation resistance and reduce the coefficient of thermal expansion (CTE); Co can stabilize the magnetic structure, adjust the expansion curve, and improve mechanical properties; Mo can stabilize the crystal lattice and reduce high-temperature deformation; Mn can improve the uniformity of the structure and reduce brittleness; Cu can improve electrical conductivity and thermal processing performance. Based on the foregoing principles, those skilled in the art can select trace element nanoparticles according to actual needs and application scenarios, as long as they can achieve the technical principles of this application, they all fall within the protection scope of this application.

[0035] In some embodiments, based on the total mass of Fe, Ni, Cr, Co, Mo, Mn, and Cu, the mass fractions of Cr, Co, Mo, Mn, and Cu are 0.5% to 5%. And / or the average particle size of the trace element nanoparticles is 50 nm to 200 nm.

[0036] For example, those skilled in the art can select the mass fraction and average particle size of trace element particles as needed. This allows the CTE of the slurry to better match that of diamond and improves its oxidation resistance. It also reduces the probability of problems such as uneven alloy structure and increased resistivity. Within this range, trace element nanoparticles are beneficial for improving their dispersion uniformity in metal powders and reducing local performance fluctuations caused by agglomeration; at the same time, the high specific surface area can promote the rapid formation of "sintering necks" during sintering, reduce porosity, and improve the density and mechanical reliability of the metal interconnect layer.

[0037] In some embodiments, the binder includes one or more of ethyl cellulose and polyvinyl alcohol; the dispersant includes one or more of polyvinylamine, polyvinylpyrrolidone, polyacrylate, modified polyester, modified polyurethane, modified acrylate or modified polyether; and the organic solvent includes one or more of terpineol and butanol.

[0038] The binder is ethyl cellulose (EC, oil-soluble) or polyvinyl alcohol (PVA, water-soluble), which maintains particle adhesion before and after drying, provides formability, controls rheology, and forms easily removable carbon-based residues during the degreasing stage, thus facilitating subsequent sintering.

[0039] The solvent is terpineol, butanol, or a mixture thereof, used to dissolve / swell the binder and adjust the evaporation rate and rheology. The drying and debinding effects are determined by the solvent.

[0040] The dispersant is one or more of polyvinylamine, polyvinylpyrrolidone, polyacrylate, modified polyester, modified polyurethane, modified acrylate or modified polyether, for example, it can be a BYK (BYK-Chemie GmbH) series of dispersants, which reduces the viscosity of the slurry and improves the dispersion stability of solid particles in the liquid medium.

[0041] like Figure 2 As shown, this application provides a method for preparing a diamond through-hole metallized interconnect substrate, comprising: step S01: pre-treating the diamond substrate, the pre-treating including through-hole cleaning and interface activation treatment; step S02: filling the pre-treated diamond substrate with alloy slurry; step S03: subjecting the filled diamond substrate to staged heat treatment and post-treatment to obtain an encapsulation substrate, such as... Figure 1 As shown.

[0042] In some embodiments, pretreatment of the diamond substrate includes cleaning and pretreating the surface of the diamond vias: before the alloy slurry fills the vias, the inner wall of the diamond vias is surface-treated to improve the wettability and adhesion of the slurry. Then, plasma activation treatment is used, or an ALD technique is used to deposit a 50-200 nm metal seed layer (such as Ti, Cu or their alloys), which effectively improves the interfacial bonding strength and overall structural stability after sintering.

[0043] In some embodiments, the alloy slurry comprises: a low-solids content alloy slurry comprising 30% to 45% solids, 4% to 8% binder, and 0.3% to 1.0% dispersant, with the remainder being organic solvents; or a medium-solids content alloy slurry comprising 50% to 65% solids, 3% to 6% binder, and 0.5% to 1.5% dispersant, with the remainder being organic solvents; or a high-solids content alloy slurry comprising 70% to 85% solids, 1% to 4% binder, and 0.5% to 1.2% dispersant, with the remainder being organic solvents.

[0044] The preparation of the alloy slurry includes: first, completely dissolving the binder in a solvent (appropriate heating, such as to 50°C, can promote dissolution); then adding a dispersant and mixing thoroughly; next, gradually adding metal powder (fineer powders can be added first, followed by coarser particles) to ensure uniform particle dispersion. Then, homogenizing the slurry using a three-roll mill or high-shear disperser until it reaches the preset fineness and rheological properties. Finally, degassing is performed using a vacuum degassing device to remove internal microbubbles and prevent voids or defects from forming during subsequent molding or sintering.

[0045] In some embodiments, the filling method includes capillary wetting, screen printing, or vacuum pressing. The slurry is filled into the through-hole using screen printing, dispensing, vacuum pressing, or capillary wetting. Capillary wetting is suitable for high-flowability, low-solids slurries, especially for ultra-fine through-holes with a pore size ≤20μm. Specific steps include: first, adjusting the slurry to a low viscosity state to ensure good flowability and wetting properties; then, through contact or localized dripping, allowing the slurry to automatically enter the through-hole by capillary force; finally, plasma pretreatment can be used to enhance the wettability of the through-hole wall, further improving the capillary wetting speed and filling depth.

[0046] In some embodiments, the staged heat treatment includes a first-temperature drying process, a second-temperature debinding process, and a third-temperature sintering process. For example, it could be: a first-temperature drying process (approximately 100°C): a low-temperature stage where the powder is slowly heated to dryness and the solvent is removed; a second-temperature debinding process (approximately 200-350°C): a medium-temperature stage where the binder and dispersant are rapidly removed, and this is carried out in an inert atmosphere or a low-proportion reducing atmosphere to prevent oxidation; and a third-temperature sintering process (approximately 700-900°C): a high-temperature stage where the powder is sintered and densified, and this is carried out in a vacuum, argon, or hydrogen protective atmosphere to effectively prevent metal oxidation. The entire heating / holding process requires strict control of the heating rate to avoid cracking of the sample due to rapid gas escape or thermal stress.

[0047] It should be noted that the oxygen content of metal powder and slurry systems should be strictly controlled throughout the preparation, drying, debinding and sintering process. It is preferable to use an inert atmosphere (nitrogen or argon) or a reducing atmosphere (such as a hydrogen-nitrogen mixture) for protection to prevent powder oxidation and avoid problems such as decreased electrical conductivity, loose structure and deterioration of interfacial adhesion.

[0048] In some embodiments, the method further includes removing trace metal layers from the material surface through chemical mechanical polishing to achieve global planarization and an ultra-smooth surface.

[0049] Specifically, in some embodiments, the method for preparing the encapsulation substrate includes the following steps: Powder preparation The main metal powder consists of Fe and Ni powder (based on the total mass of the solid components, Fe powder accounts for 61 at%~66 at% and Ni powder accounts for 33 at%~38 at%), with a particle size controlled at 1µm~5µm; trace element nanoparticles (one or more of Cr, Co, Mo, Mn, and Cu) are doped, accounting for 0.5 at%~5 at% of the total mass of the solid components, with a particle size of 100~120nm. The mixed powder is dried in an inert gas (nitrogen or argon) environment (temperature 80℃~120℃, time 2h~4h). After drying, it is sieved through a 100~200 mesh sieve to remove agglomerated particles, and then subjected to surface activation treatment to ensure powder dispersibility and compatibility with subsequent slurry.

[0050] Slurry formulation (based on total slurry mass) The solid components (Fe-Ni main powder + trace element nanopowder) contain 60wt%~78wt%, ethyl cellulose (binder) 3wt%~6wt%, terpineol (organic solvent) 14wt%~20wt%, and dispersant (polyvinyl alcohol amine or BYK series) 0.8wt%~1.2wt%. The organic solvent is added to make up the total mass percentage of all components to 100%.

[0051] Slurry preparation The binder is first dissolved in the solvent (heated to ≤60°C), then the dispersant is added and stirred, and then the powder is gradually added (first the trace element nanopowder is added to the mixture, then the Fe-Ni main metal powder is added), and the mixture is ground several times with a three-roll mill or a high-shear disperser, and then degassed under vacuum.

[0052] Diamond substrate pretreatment Pretreatment of the through-holes in the diamond substrate: Acetone, ethanol, and deionized water are sequentially ultrasonically cleaned for 15-20 minutes each to remove oil, dust, and other impurities from the inner wall of the through-holes and the substrate surface. After cleaning, the through-holes are vacuum-dried at 80-120℃ for 2-4 hours. Subsequently, interface activation is performed: O2 plasma activation (power 100W-300W, processing time 5-15 minutes) is used to improve the surface energy of the inner wall of the through-holes and the wettability of the slurry. If extremely high interfacial adhesion is required, a metal seed layer can be deposited using ALD technology after plasma activation (first depositing a 50nm Ti layer as a transition layer, then depositing a 50nm Cu layer as a conductive transition layer) to further improve the wetting effect of the alloy slurry on the inner wall of the through-holes and the adhesion of subsequent sintering.

[0053] Fill method The process mainly involves multi-layer stacking of screen printing, combined with vacuum-assisted pressing (VAF) or capillary wetting when necessary, and low-temperature pre-drying (80°C~100°C) between printed layers to remove solvent.

[0054] Degreasing / Sintering (Baseline) Step 1, Low-temperature pre-drying: Under air or nitrogen atmosphere, heat to 100°C at 5°C / min~10°C / min and hold for 30min~60min to completely remove terpineol solvent from the slurry; Step 2, Medium-temperature debinding: Switch to nitrogen atmosphere or N2 / H2 mixed reducing atmosphere (H2 volume percentage 5%~10%), heat to 200°C~350°C at 1°C / min~2°C / min and hold for 60min~90min to remove ethyl cellulose binder and dispersant, avoiding organic component residue; Step 3, High-temperature sintering: Switch to Ar / H2 mixed atmosphere (volume ratio 95:5) or vacuum environment (≤1×10⁻⁶). -3 The metal powder is sintered and densified by heating to 850°C at a rate of ≤2°C / min and holding for 60-120 min. The fourth step is cooling: the temperature is lowered to below 200°C at a rate of 1-3°C / min, and then allowed to cool naturally to room temperature to avoid thermal stress between the metal interconnect layer and the diamond substrate due to rapid cooling. Depending on the actual density requirements, a secondary HIP (hot isostatic pressing) densification treatment can be added (temperature 800-850°C, pressure 50-100MPa, holding for 30-60 min).

[0055] Post-processing The sintered packaging substrate undergoes surface planarization treatment: chemical mechanical polishing (CMP) or grinding is used. CMP can be divided into coarse polishing (SiO2 polishing slurry particle size 100nm~200nm, rotation speed 300rpm, pressure 20kPa, polishing 5min~10min) and fine polishing (SiO2 polishing slurry particle size 50nm~100nm, rotation speed 500rpm, pressure 10kPa, polishing 10min~15min). After polishing or grinding, the substrate is ultrasonically cleaned with deionized water and ethanol in sequence, and then vacuum dried at 60℃~80℃ for 1h~2h to finally obtain a diamond through-hole metallized interconnect substrate with a smooth surface.

[0056] Thermal expansion coefficient test method In some embodiments of the present invention, the coefficient of thermal expansion of the sintered metal-filled structure is measured using a thermomechanical analyzer (TMA) or a differential scanning calorimetry / mechanical analysis system (DSC / TMA). The first step is sample preparation: the sintered and polished diamond through-hole substrate is cut into test pieces with dimensions of 3mm × 3mm × 0.5~1mm. The second step is applying a test load: the sample is placed on the TMA test stage, and a constant micro-load of 10mN~20mN is applied to ensure that the thermally induced deformation can be accurately recorded. The third step is temperature scanning: a heating test is performed within the range of room temperature to 400℃, with a heating rate of 3℃ / min~5℃ / min, while simultaneously recording the length change ΔL of the sample as a function of temperature. The fourth step is calculating the coefficient of linear expansion α: α = (ΔL / ΔT) / L0, where L0 is the initial length, ΔL is the thermal deformation, and ΔT is the temperature difference.

[0057] Volume resistivity test method In embodiments of the present invention, the volume resistivity of the filler metal is measured using a four-probe method or a micro-area four-probe testing stage. The first step is sample preparation: a flat metal surface is formed at the top and bottom of the filled via (after CMP). The second step is to arrange the four-probe testing device, placing four probes on the sample surface with a probe spacing of 50 μm to 100 μm, and providing a constant current source I (typically 1 mA to 10 mA). The third step is to record data, measure the voltage V between the probes, and repeat the measurement in multiple different via regions to obtain stable voltage readings. The fourth step is to calculate the volume resistivity ρ: ρ = (πt / ln2)·(V / I), where t is the metal thickness of the effective conductive path or the via depth.

[0058] Density testing methods In embodiments of the present invention, the density of the metal-filled system can be determined using cross-sectional microstructure analysis (SEM). The first step is to prepare the cross-section of the through-hole (mechanical polishing or FIB). The second step is to analyze the porosity using SEM images. The density D = (1-P) × 100%.

[0059] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the experimental reagents used in the following embodiments are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or through existing methods; unless otherwise specified, the amounts of experimental reagents used are the amounts used in conventional experimental operations; unless otherwise specified, the experimental methods are all conventional methods.

[0060] Examples 1-3, Comparative Example 1 Diamond through-hole metallized interconnect substrates for Examples 1-3 and Comparative Example 1 were prepared according to the preparation methods provided in Table 1 and above, and then tested. The differences between Examples 1-3 and Comparative Example 1 are detailed in Table 1 below. The test results are shown in Table 2.

[0061] Table 1

[0062] Table 2

[0063] As can be seen from Tables 1 and 2, the alloy slurry for diamond through-hole filling provided by the present invention has high sintering density, low resistivity, stable and controllable material properties, and is not prone to producing high porosity and oxide scale during sintering.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A diamond through-hole metallized interconnect substrate, characterized in that, Includes a diamond substrate and a metallized interconnect layer filling the vias in the diamond substrate; The metallized interconnect layer includes Fe, Ni, and one or more elements selected from Cr, Co, Mo, Mn, and Cu.

2. The diamond through-hole metallized interconnect substrate according to claim 1, characterized in that, In the metallized interconnect layer, the Fe content is 61at%~66at, and the Ni content is 33at%~38at.

3. The diamond through-hole metallized interconnect substrate according to claim 1, characterized in that, In the metallized interconnect layer, the total content of Cr, Co, Mo, Mn and Cu is 0.5 at% to 5 at%.

4. The diamond through-hole metallized interconnect substrate according to claim 1, characterized in that, The metallized interconnect layer satisfies the following conditions: thermal expansion coefficient 1.0ppm / K~1.3ppm / K; and / or resistivity ≤1.5μΩ·m.

5. The diamond through-hole metallized interconnect substrate according to claim 1, characterized in that, The metallized interconnect layer is formed by sintering an alloy paste.

6. The diamond through-hole metallized interconnect substrate according to claim 5, characterized in that, The alloy slurry comprises the following components by mass fraction: 30% to 85% Fe and Ni, and one or more of Cr, Co, Mo, Mn, and Cu; 1% to 8% binder; 0.3% to 1.5% dispersant; and the remainder being organic solvent.

7. The diamond through-hole metallized interconnect substrate according to claim 6, characterized in that, Based on the total mass of Fe, Ni, Cr, Co, Mo, Mn, and Cu, the mass fraction of Cr, Co, Mo, Mn, and Cu is 0.5% to 5%.

8. The diamond through-hole metallized interconnect substrate according to claim 7, characterized in that, The Cr, Co, Mo, Mn, and Cu are nanoparticles with an average particle size of 50 nm to 200 nm.

9. A method for preparing a diamond through-hole metallized interconnect substrate as described in any one of claims 1 to 8, characterized in that, include: Step S01: Pre-treat the diamond substrate, the pre-treatment including through-hole cleaning and interface activation treatment; Step S02: Fill the pretreated diamond substrate with alloy slurry; Step S03: Perform staged heat treatment and post-treatment on the filled diamond substrate to obtain a diamond through-hole metallized interconnect substrate.

10. The preparation method according to claim 9, characterized in that, The phased heat treatment includes a first-temperature drying process, a second-temperature debinding process, and a third-temperature sintering process.

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