A PECVD SiO2 thick mask based ICP-DRIE process for diamond was developed using a CF4-assisted O2 plasma to suppress micro-masking and achieve stable deep etching. The process produced high quality microchannels over 260 $\mu \mathrm{m}$ deep with aspect ratios above 8. Based on this, diamond microchannel heat sinks with integrated heaters and thermocouples were fabricated and tested, exhibiting excellent thermal performance with a total thermal resistance of 0.37 K/W and a heat flux density exceeding 640 W/cm2 under a 25° C temperature rise. The proposed approach provides an effective route for high power device cooling using diamond microchannel heat sinks.

Polymer-based embedded silicon-based fan-out (P-eSiFO) is a new packaging technique, which provides a way to high-density integration of high-performance chiplets. However, integrating multiple materials with diverse physical properties in the P-eSiFO leads to substantial warpage during downstream high-temperature manufacturing processes. In this study, a thermomechanical model of a P-eSiFO was developed to examine the thermomechanical with varying structural parameters and material selections. Test dies having an area of 0.5 cm(2) were embedded in a 500-mu m-thick silicon carrier following the P-eSiFO process. After careful parameters, optimization chip warpage can effectively decrease by over 60%. Experimental results showed that the height difference between the embedded chip and its silicon interposer can be reduced down to 1 mu m with optimized parameters after high-temperature processes. This work provides useful insights for addressing multimaterial warpage concerns during thermal processes in advanced packaging.

As the power density of electronic devices continues to rise, conventional packaging structures face increasing challenges in meeting thermal management requirements. Diamond, owing to its superior thermal conductivity and stability, is considered a promising substrate material for high-performance microchannel heat sinks. The inlet configuration plays a decisive role in influencing coolant flow distribution, convective coverage, and overall thermal resistance. This work conducts steady-state conjugated thermal-fluid simulations to evaluate five inlet structure designs, incorporating variations in pre-diffusion region width (narrow or wide) and inlet direction (axial or perpendicular). The simulation model applies a uniform heat flux of 1500 W/cm2 on the bottom surface, with an inlet pressure of 50 kPa and water as the coolant. Results indicate that wider pre-diffusion regions significantly improve flow uniformity and enhance heat transfer coverage, leading to reductions in both maximum chip temperature and total thermal resistance. The wide pre-diffusion perpendicular inlet (W-PI) achieves the best thermal performance, with a peak temperature of 584 K and a total thermal resistance of 1.20 K/W. The wide circular perpendicular inlet (W-CPI) demonstrates the most uniform velocity distribution, with slightly lower heat removal efficiency. In contrast, narrow pre-diffusion structures result in uneven flow distribution and elevated thermal resistance. These findings offer quantitative guidance for the structural optimization of diamond-based microchannel heat sinks in high power density electronics.

A novel two-phase jet impingement cooling strategy integrating large-area copper-inverse-opal (CIO) wicks with a 3D-printed microchannel manifold using Novec-649 coolant is presented. The design maximizes critical heat flux (CHF) and minimizes surface superheat through controlled coolant distribution and efficient vapor venting. Three prototype configurations with varying wick thicknesses and vent heights are tested on a 2.5 cm x 1.5 cm heated area, achieving a maximum CHF of similar to 140 W/cm(2) at similar to 35 K superheat with coolant flow rate of 2.5 L/min. This approach demonstrates effective thermal management capability, offering a promising solution to high-power electronics cooling.

This paper reports the field emission (FE) current stability of a diamond nanowire (DNW) array. Assembled with a silicon anode with a 1.03 μm gap, the FE properties, as well as the current stability of the DNW cathode, were systematically evaluated in a vacuum test system under different vacuum degrees, current densities, and atmospheres. Experiments demonstrate that lower pressure and current density can improve FE properties and current stability. In addition, compared to air and compressed air, DNWs exhibit higher FE properties and current stability in N2. DNWs achieve a remarkably low turn-on field of 1.65 V/μm and a high current density of 265.38 mA/cm2. Notably, they demonstrate merely 0.70% current fluctuation under test conditions of 1.2 × 10−4 Pa and 0.1 mA/cm2. Additionally, based on the Fowler–Nordheim theory, the change in work function after gas adsorption was analyzed, and the noise generation mechanism was derived from the noise power spectrum. The current exponent is determined as 1.94, while the frequency exponent ranges from 0.92 to 1.32, confirming that the dominant noise mechanism in DNWs arises from surface work function fluctuations due to the adsorption and desorption of residual gas.

This work proposes and develops an inductively coupled plasma reactive ion etching (ICP-DRIE) diamond etching technique using plasma-enhanced chemical vapor deposition (PECVD)-deposited SiO2 as the etch mask. On a 300 mu m-thick polycrystalline diamond substrate, a 16.0 +/- 0.3 mu m SiO2 layer was deposited by PECVD and patterned using an Al hard mask. Both Al and SiO2 hard masks were patterned via ICP-RIE. The ICP and bias powers were fixed, and the effects of different O-2 flow rates and chamber pressures on the diamond etch rate and SiO2 mask selectivity were systematically investigated. Step profilometry was employed for accurate depth measurement, and scanning electron microscopy was used to observe the etched mesa morphology. The results show that the optimized ICP-DRIE recipe consists of an ICP power of 1600 W, a bias power of 100 W, an O-2 flow rate of 49 sccm, and a chamber pressure of 5 mTorr, achieving a diamond etch rate of 287.2 nm min(-1), a SiO2 selectivity of 17.3, and a sidewall angle of 88.3 degrees for 25 mu m-wide mesas. After 2 h of etching, the etch rate and selectivity were same as those after 20 min, but severe grass formation prevented further etching. It is estimated that a 16.0 mu m-thick SiO2 mask can support a maximum diamond etch depth of up to 277 mu m. This study provides a new approach and reliable technical foundation for deep diamond etching.

This paper reports a novel diamond nanowire (DNW) field emission triode (FET) and its application research as buffer amplifiers and vacuum switches. A DNW cathode and gate-anode integrated structure was fabricated by microfabrication, followed by the assembly together forming the field emission (FE) triode whose FE performance and applications as buffer amplifiers and vacuum switches were tested in a vacuum measurement system. The emission current of DNW-FET was modulated by the gate voltage, achieving a current density as high as 31.27 mA/cm(2). DNW-FET exhibits moderate amplification factor (2.98), high transconductance (464.2 mu S), low anode resistance (865.8 Omega). AC amplification test shows that DNW-FET has an AC gain of 3.86 dB, indicating its potential as buffer amplifiers. Vacuum switching test demonstrates fast switching response (3 mu s), high voltage change rate (16.09 V/mu s), high stability in conducting state (0.69%) and low power loss (20.65 mu W), suggesting its viability for vacuum switches.

This work proposes and develops an inductively coupled plasma reactive ion etching (ICP-DRIE) diamond etching technique using plasma-enhanced chemical vapor deposition (PECVD)-deposited SiO 2 as the etch mask. On a 300 μ m-thick polycrystalline diamond substrate, a 16.0 ± 0.3 μ m SiO 2 layer was deposited by PECVD and patterned using an Al hard mask. Both Al and SiO 2 hard masks were patterned via ICP-RIE. The ICP and bias powers were fixed, and the effects of different O 2 flow rates and chamber pressures on the diamond etch rate and SiO 2 mask selectivity were systematically investigated. Step profilometry was employed for accurate depth measurement, and scanning electron microscopy was used to observe the etched mesa morphology. The results show that the optimized ICP-DRIE recipe consists of an ICP power of 1600 W, a bias power of 100 W, an O 2 flow rate of 49 sccm, and a chamber pressure of 5 mTorr, achieving a diamond etch rate of 287.2 nm min −1 , a SiO 2 selectivity of 17.3, and a sidewall angle of 88.3° for 25 μ m-wide mesas. After 2 h of etching, the etch rate and selectivity were same as those after 20 min, but severe grass formation prevented further etching. It is estimated that a 16.0 μ m-thick SiO 2 mask can support a maximum diamond etch depth of up to 277 μ m. This study provides a new approach and reliable technical foundation for deep diamond etching.

This paper investigated the structural and area influence on the fabrication yield and the characteristics of the diode and betavoltaic battery. Different structures and areas of the back-junction back-contact (BJBC) PN junction with suspended 1.5 mu m-Si thin-film were prepared by microfabrication based on silicon-on-insulator (SOI) substrates. The samples were fixed and wire-bonded on a custom-designed-and-processed sample holder and PCB board on the SEM stage so that their betavoltaic battery performance was tested using high-energy electron beams to simulate the tritium source. Before splintered to chips, all devices on the 4-inch wafer maintained their structures well and exhibited good rectification characteristics. However, the larger area the suspended thin film was, the more severely it was damaged after splintering. The collection efficiency of radiation-generated carriers were enhanced by reducing collection electrode spacing and increasing the number of electrodes, thereby improving the battery performance, which proves the advantage of design flexibility in doping regions and electrode shapes in BJBC structures. The large device area made the reverse saturation current of the PN junction decreasing an order of magnitude and so resulted in the betavoltaic battery performance degradation. As a result, the optimal betavoltaic battery performance was achieved by 1.2 x 1.2 mm2 area BJBC PN junction with the interdigitated structure of 10 mu m-wide P+/N+ regions and 25 mu m spacing, yielding Isc = 0.729 mu A, Voc = 0.194 V, Pm = 84.1 nW, eta = 1.09 %.

This paper reports the field emission (FE) characteristics of a diamond nanowires (DNWs) array. The nanocrystalline diamond (NCD) film was deposited on silicon by microwave plasma chemical vapor deposition (MPCVD) and then annealed in air forming DNWs and hydrogenated at last. A high-field flat-plate emission test structure with a 1.03 mu m gap between anode and cathode was prepared and the electrical properties proved it feasible. The FE performance of DNWs array was measured in a vacuum test system and that of NCDs film as a comparison. Finally, their FE parameters were analyzed and extracted based on the Fowler-Nordheim (F-N) theory. The results show that transforming NCDs film into DNWs array can improve the FE characteristics greatly. The turn-on field is as low as 1.36 V mu m-1 dropping by one order of magnitude, while the field enhancement factor and FE current density are up to 156.68 and 484.75 mA cm-2 respectively rising both by two orders of magnitude. This excellent FE performance stems from the characteristics of large aspect ratio, very small tip radius and high density of DNWs.

Embedded silicon fan-out packaging (eSiFO) features excellent electrical and thermal performances as well as scalability to 3-D packaging and heterogeneous integration, making it a promising packaging technology for chiplet integration. Nevertheless, conventional eSiFO implementation resorts to a dry film vacuum lamination process for surface passivation of reconstituted wafers, which is challenged by low lithographic resolution, limited compatibility, difficulty in filling high-aspect trenches, and elevated costs due to the inherent attributes of dry film materials. This work proposes a new surface passivation method of eSiFO, which uses Parylene to fill trenches and polyimide (PI) to passivate the reconstructed wafer surface. The trench with an aspect ratio greater than 10 and a width less than $5 ~\mu \text{m}$ can be filled successfully. The height difference of the reconstructed wafer surface after polymer passivation was less than $1 ~\mu \text{m}$ . Finally, three different wiring methods were proposed to implement two-layer high-density damascene wiring (linewidth/line space $ < 2 /2 ~\mu \text{m}$ ). This approach is characterized by its ease of implementation, cost-effectiveness, superior compatibility, high chip area efficiency, minimized die shift, and capability to facilitate high-density redistribution layer (RDL) wiring. Given these attributes, this approach indicates a propitious future for advanced packaging techniques of chiplet.

金刚石薄膜具有负电子亲合能、高热导率和极强的化学惰性等优势,作为场发射材料引起了广泛关注.回顾了金刚石薄膜的分类,介绍了氢化金刚石薄膜具有的负电子亲合能特性,分析了金刚石薄膜场发射特性的影响因素,列举了场发射特性的优化方向,并总结了文献中报道的金刚石薄膜与其他材料复合获得的场发射阴极的性能,对于分析和改进金刚石薄膜器件场发射性能具有重要意义.

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) were synthesized through a complexation reaction involving silver nitrate (AgNO3) and ammonia, followed by reduction using glucose. The resulting AgNPs exhibited a uniform size distribution ranging from 20 nm to 50 nm. Subsequently, 3-aminopropyl triethoxysilane (APTES) was employed to modify a PDMS substrate that had been surface-treated with oxygen plasma. This process facilitated the self-assembly of AgNPs onto the substrate. A systematic evaluation of the impact of various experimental conditions on substrate performance led to the development of a SERS substrate with excellent performance and an Enhanced Factor (EF). Utilizing this substrate, impressive detection limits of 10-10 M for R6G (Rhodamine 6G) and 10-8 M for Thiram were achieved. The substrate was successfully employed for detecting pesticide residues on apples, yielding highly satisfactory results. The flexible SERS substrate demonstrates great potential for real-world applications, including detection in complex scenarios.

以GaN为代表的新一代半导体材料具有宽禁带、高电子饱和速率、高击穿场强等优异的电学性能，使得射频、电力电子器件有了具备更高功率能力的可能，目前限制器件功率提升的主要瓶颈是缺少与之匹配的散热手段。具有极高热导率的金刚石已成为提升器件散热能力的重要材料，学术界针对金刚石与功率器件集成的先进热管理技术已经开展了大量有益的研究与探索，但是由于金刚石具有极强的化学惰性和超高的硬度，在实际集成和工艺加工过程中，金刚石-GaN界面容易出现热性能和可靠性问题，甚至会导致器件失效。对金刚石热管理技术的研究进展和存在的问题进行了深入分析，并对未来主要工作方向做了展望。

This paper reports the field emission (FE) properties of a novel array of diamond nanowires (DNWs). The DNWs structure was prepared by annealing the nano-crystalline diamond (NCD) films obtained by MPCVD in air, and the surface hydrogenation was realized by using hydrogen plasma. A flat anode was fabricated by micromachining, and assembled respectively with NCD film and nanowire cathodes to achieve a FE test structure with a gap of 1.03 μm. The FE properties of NCD films and DNWs were tested under a vacuum of 2.6×10 -4 Pa. The results show that the FE current density of the DNWs array is as high as 174 mA/cm 2 and the turn-on field is as low as 2.3 V/μm, which is significantly better than that of the NCD film.

Fiber-reinforced polymeric composites (FRPCs) with selective fiber orientations are finding applications in building biological constructs, smart materials and energy devices. Field-assisted additive manufacturing (AM) has emerged as one of the promising methods for creating FRPC structures. Compared to other AM processes and due to the liquid form of the raw materials, vat photopolymerization has shown higher potential in building FRPCs with selective fiber orientation. Compared to other methods of controlling the fiber orientation during AM processes, magnetic field-assisted fiber reorientation, is a relatively easy-to-use contactless method that has been effectively paired with vat photopolymerization. One of the major issues in magnetic field-assisted vat photo polymerization is the dispersion instability of the particles in resin system, which leads to separation between the resin components and dispersed particles and results in non-uniform particle distribution during the printing process. In this study, ferromagnetic particle-loaded photocurable resins are developed through surface modification of the particles to achieve more uniform particle dispersion, more dispersion-stable resins systems and enhanced mechanical properties of FRPCs. Magnetite particles were functionalized under silanization reactions and mixed with two photocurable resins. Fourier-transform infrared spectroscopy (FTIR) analysis was used to select the matching composition of silane compounds and verify the functionality of the treated magnetite particles for each resin mixture. Dispersion stability of the developed resin system was verified by visual observation of the resin mixture and image analysis of microscope images. To provide a better guideline for 3D printing the developed resin system, cure depth of each resin system containing different particle fractions is studied. Tensile tests are devised to understand the effects of particle content, orientation, and surface treatment on mechanical properties of the 3D printed FRPCs. Results of this study suggest that an optimized particle-resin system can be developed through surface treatment of magnetite particles with functional groups.

目的·探讨产后血栓形成的高危因素,为产后血栓的预防提供指导.方法·回顾性分析2018—2020年间于上海交通大学医学院附属国际和平妇幼保健院分娩的孕产妇电子病例45262例,其中病例组60例,为诊断为产后静脉血栓或者肺栓塞的产妇;对照组45202例,为未发生产后血栓的产妇.通过多因素Logistic回归分析寻找产后血栓发生的危险因素.结果·产后静脉血栓的发病率为130/10万,肺栓塞46/10万,产后血栓性疾病的发病率呈现逐年增高的趋势(P<0.05),产后血栓的发生部位以左下肢为主.病例组产妇分娩时的平均年龄为(33.52±4.79)岁,对照组的平均年龄为(31.35±4.01)岁.病例组中发生早产的产妇占比是对照组的2.05倍,孕前超重及肥胖的产妇占比是对照组的1.94倍.多因素Logistic回归分析显示产妇年龄大(aOR=1.10,95％CI 1.04～1.17)、分娩孕周小(aOR=0.88,95％CI 0.78～0.99)、本科学历以下(aOR=2.24,95％CI 1.20～4.18)、择期剖宫产(aOR=6.68,95％CI 2.56～17.41)、急诊剖宫产(aOR=14.40,95％CI 5.37～38.63)及孕前超重和肥胖(aOR=1.91,95％CI 1.04～3.49)的产妇发生产后血栓的风险增加.结论·产妇年龄大、受教育程度低、分娩孕周小、超重以及剖宫产的分娩方式是产后血栓的独立危险因素,其中最突出的危险因素是急诊剖宫产.产后静脉血栓的发生和多种危险因素相关,且可导致孕产妇死亡,临床上需要及时做好血栓风险的评估工作,对于有高危因素的产妇尽早进行预防措施,以降低产后血栓的发生.

Carbon fiber reinforced polymer (CFRP) composites are indispensable in a variety of applications, because of their high specific strength. CFRPs are generally constructed by carbon fibers as reinforcements and crosslinked polymers as binders. Due to the irreversible nature of the crosslinked polymers, CFRPs are neither repairable nor recyclable. Once the material is damaged or out of service, landfill or incineration is the typical way to deal with the waste. These methods take no advantages of the residue value of the waste and add burdens to the environment. To reduce waste and cost, it is desirable to develop effective recycling technologies to reserve the residue value of carbon fiber and polymer matrix. In the past decade, chemical recycling by cleaving the covalent bonds in a solvent has been considered as an ideal path for the recycling of CFRP wastes, because it has the potential to recover both valuable CFs and polymer matrix. In this review, the discussion is focused on the progress in the chemical recycling of CFRP. The primary matrix resin of CFRP discussed in this review is epoxy resin which is the most widely used polymer matrix. In addition, the challenges and outlook are provided.

目的·探讨难治性产后出血导致产科急症子宫切除的危险因素以及相关预防措施.方法·回顾性分析2014年1月—2020年12月于上海交通大学医学院附属国际和平妇幼保健院收治的110934例产妇的临床资料.根据收治时间,选择其中2015—2017年段(n=48984)和2018—2020年段(n=45262)的产妇为研究对象,分析其产科急症子宫切除发生率的情况;选择其中发生难治性产后出血的108例产妇为研究对象,根据是否行子宫切除,将其分为子宫切除组(n=22)与子宫保留组(n=86),采用单因素分析及多因素Logistic回归模型对该2组患者的临床资料进行比较分析,并探究产科急症子宫切除的危险因素.结果·与2015—2017年段相比,2018—2020年段的产科急症子宫切除发生率下降(P=0.039);与子宫保留组相比,子宫切除组患者的年龄偏大,孕次≥2次、单胎妊娠、发生妊娠合并症(前置胎盘、胎盘植入、瘢痕子宫等)、羊水栓塞者的占比均较高,产后出血量更大(均P<0.05).多因素Logistic回归分析显示,患者的年龄、产后出血量均是难治性产后出血导致产科急症子宫切除的独立危险因素(P<0.05).结论·难治性产后出血产妇的年龄越高、出血量越大,越容易导致产科急症子宫切除的发生.临床上需尽早开展监测并进行干预,以降低该类患者产科急症子宫切除的发生率.

With the rapid development of flexible electronics, an increasing number of microfabrication strategies originating from the Si-based integrated circuits field have been explored on organic materials. Parylene C, a polymer, has been widely used in the microelectromechanical systems field because of its outstanding fabrication merits, such as room-temperature processability, conformal coating, and precise thin film deposition capability with the thickness tunable from 1 nm to 100 μm. As a good dielectric material, the Parylene C is also suitable for interlayer dielectrics in flexible electronics. This study develops an optimized chemical mechanical polishing (CMP) technique of Parylene C for high-density redistribution wiring in high-performance flexible electronics. The roughness of the Parylene C surface after CMP was as low as 14.3 ± 1.5 Å. The problems of slurry pollution and mechanical failure of the Parylene film that degrade the dielectric performance of the Parylene C could be avoided by taking the optimized CMP method. The multi-material structure constructed by Parylene C, Silicon and electroplated Copper was prepared and polished using the optimized CMP process. Additionally, a flexible wiring sample has been successfully patterned by the Damascene process through the optimized CMP process. In this sample, both the distance between each wire and the wire width were as small as 5 μm. The optimized Parylene C CMP process is easy-to-realize, highly efficient, low cost, and with minor defects; it provides a promising way to achieve high-density interconnection in high-performance flexible electronic devices.