A review of silicon-based wafer bonding processes,an approach to realize the monolithic integration of Si-CMOS and Ⅲ-Ⅴ-on-Si wafers

The heterogeneous integration of Ⅲ-Ⅴ devices with Si-CMOS on a common Si platform has shown great promise in the new generations of electrical and optical systems for novel applications,such as HEMT or LED with integrated control cir-cuitry.For heterogeneous integration,direct wafer bonding(DWB)techniques can overcome the materials and thermal mis-match issues by directly bonding dissimilar materials systems and device structures together.In addition,DWB can perform at wafer-level,which eases the requirements for integration alignment and increases the scalability for volume production.In this paper,a brief review of the different bonding technologies is discussed.After that,three main DWB techniques of single-,double-and multi-bonding are presented with the demonstrations of various heterogeneous integration applications.Mean-while,the integration challenges,such as micro-defects,surface roughness and bonding yield are discussed in detail.     

Crystal structure of cis-[Ru(bpy)2{PMe(o-tol)2}Cl+][ClO−4]: Steric effects in some PMen(o-tol)3−n (n = 1-3) derivatives of ruthenium(II)

The complex cis-[Ru(bpy)₂{PMe(o-tol)₂}Cl⁺][ClO^– ₄] crystallizes in space group P2₁/c witha = 9.375(2) Å, b = 22.019(7) Å, c = 16.153(4) Å, = 90.83(2)°, V = 3333.9(16) ų and D(calc'd) = 1.547 g/cm³ for Z = 4. The Ru-PMe(o-tol)₂ bond length of 2.357(3) Å is significantly longer than distances of Ru-PMe₂(o-tol) = 2.324(2) Å and Ru-PMe₃ = 2.310(2) Å in analogous complexes. The corresponding Ru-P(o-tol)₃ complex has eluded synthesis, probably due to steric hindrance.     

Crystal structure of the methanol solvate of (η5-cyclopentadienyl)[1,2-bis(diphenylphosphino)ethane] nitroruthunium(II) Ru(η5-C5H5)dppe)(NO2)·CH3OH

The title complex crystallizes in the centrosymmetric monoclinic space group C2/c (No. 15) withZ=8. The structure was refined toR=4.49% for those 2745 independent reflections with 2=5–50^o and |F |>6(F). Ruthenium-ligand distances are as follows: Ru-P=2.284(2) and 2.286(2) Å, Ru-NO₂=2.049(6) Å and Ru-C(Cp)=2.210(10)-2.246(9) Å. Bond lengths within the nitro ligand are N(1)-O(1)=1.226(10) Å and N(1)-O(2)=1.244(10) Å. The methanol of solvation is ordered but is subject to large thermal vibrational motions.     

Molecular structure of an extremely crowded iron(II) dihydride complex: FeH2(PMePh2)4

The crystal structure of FeH₂(PMePh₂)₄ shows this to exist as thecis isomer in the solid state with major distortions of the FeP₄ skeleton:cis P-Fe-P angles 98.1(1)–107.2(1)° andtrans P-Fe-P angle 143.3(1)°. All hydrogen atoms were refined, and the mean Fe-H separation is 1.59 Å. Long Fe-P distances, 2.187(3)–2.251(3) Å, emphasize the crowding in this molecule. Crystallographic data:a=11.684(4) Å,b=37.793(17),c=9.765(3),=90.81(1)°, andZ=4 in space groupP2₁/n (No. 14).R(F)=6.3% andR _w (F)=6.0% for 2585 observed reflections collected at —162°C.     

Crystal structure ofmer,trans-[Ru(NO2)(trpy)(PPr3) 2 + ][ClO 4 − ], a species with disordered PPr3 and NO2 ligands

The complexmer,trans-[Ru(NO₂)(trpy)(PPr₃) ₂ ⁺ ][ClO ₄ ^– ]crystallizes in the centrosymmetric orthorhombic space group Pnma withZ=4. Both the ruthenium(II) cation and the perchlorate ligand lie about crystallographic mirror planes. The nitro ligand is not coplanar with the Ru(trpy) moiety and suffers from two fold disorder about its Ru–N bond such that the two sets of oxygen atoms have symmetry-related sites above or below the crystallographic mirror plane. The n-propyl groups within the PPr₃ ligands suffer from disorder of their C() and C() atoms but share common C() sites. Ruthenium-ligand distances are: Ru–PPr₃=2.398(2)Å, Ru–NO₂=2.053(7) Å, Ru–N(trpy, outer)=2.078(6) and 2.092(6) Å and Ru–N(trpy, central) =1.965(6) Å.     

Extreme Two‐Phase Cooling from Laser‐Etched Diamond and Conformal,Template‐Fabricated Microporous Copper

This paper reports the first integration of laser‐etched polycrystalline diamond microchannels with template‐fabricated microporous copper for extreme convective boiling in a composite heat sink for power electronics and energy conversion. Diamond offers the highest thermal conductivity near room temperature, and enables aggressive heat spreading along triangular channel walls with 1:1 aspect ratio. Conformally coated porous copper with thickness 25 µm and 5 µm pore size optimizes fluid and heat transport for convective boiling within the diamond channels. Data reported here include 1280 W cm^?2 of heat removal from 0.7 cm² surface area with temperature rise beyond fluid saturation less than 21 K, corresponding to 6.3 × 10⁵ W m^?2 K^?1. This heat sink has the potential to dissipate much larger localized heat loads with small temperature nonuniformity (5 kW cm^?2 over 200 µm × 200 µm with <3 K temperature difference). A microfluidic manifold assures uniform distribution of liquid over the heat sink surface with negligible pumping power requirements (e.g., <1.4 × 10^?4 of the thermal power dissipated). This breakthrough integration of functional materials and the resulting experimental data set a very high bar for microfluidic heat removal.     

A colorimetric sensor array for detection and identification of sugars

Molecular recognition of sugars and a practical method to detect and discriminate among a large number of such similar analytes remain substantial scientific challenges. We report here a low-cost, simple colorimetric sensor array capable of identification and quantification of sugars and related compounds. Fifteen different monosaccharides, disaccharides, and artificial sweeteners were differentiated without error in 80 trials. Limits of detection at pH 7.4 for glucose were <1 mM, which is below physiologically important levels.     

1,3-Dipolar cycloaddition of alkynes to azides. Construction of operationally functional metal responsive fluorophores

The copper catalyzed 1,3-dipolar cycloaddition of 4-butoxyphenylazide with 2-, 3- or 4-ethynylpyridine furnishes 1,4-diaryltriazoles, which display turn-on fluorescence upon addition of metal cations.