Search

Photoetchable glasses (PEGs) are employed in packaging of radio frequency (RF) microsystems. However, their widescale adoption has been limited by intrinsic high dielectric losses. The present study reports results of systematic investigation of dielectric and thermodynamic properties of Barium (Ba) ion substituted Li–Al–Si-based PEGs. It is demonstrated that UV absorption characteristics remain largely unchanged upon Ba ion doping. Crystallization behavior of PEGs were determined by digital scanning calorimetry. After annealing at different temperatures, the structure and morphology of precipitated crystal phases were analyzed by x-ray diffraction and electron microscopy. Results reveal that the optimal annealing temperature was 565 °C, after which dielectric properties were measured to experience a dielectric constant and minimum dielectric loss of 4.7 and 3 × 10−3, respectively. Concomitantly, the influence of temperature on dielectric properties at constant frequency was investigated. Raman spectroscopy analyses exhibit that the incorporation of Ba ions do not participate in structural changes but rather dissociate within the glass network as network modifiers, influencing the dielectric properties of Ba-doped PEG. The improvement in dielectric and thermodynamic properties demonstrated here confirms the value of PEGs as preferred interposer materials in three-dimensional RF microsystem packaging.

Pb0.91Ba0.06La0.02(Zr0.95−xSnxTi0.05)O3 (PBLZST, x = 0.325, 0.35, 0.375, 0.4) thick films are prepared by solid-state reaction method and flow-casting method. Trace Ba2+ content is introduced to PLZST which is effective in narrowing the hysteresis loop, lowering the Curie temperature point, and improving the fatigue characteristics. Besides that, Zr:Sn ratios are adjusted to study its influence on the material’s energy storage characteristics. PBLZST ceramics with different Zr:Sn ratios are all in tetragonal perovskite structure. The increase of Sn4+ content promotes miniaturization of crystal grain and contributes to stability of antiferroelectric phase, together with enhances the phase transition field strength and breakdown field strength of PBLZST ceramics. The PBLZST ceramic has high energy storage efficiency, which is more than 80%. The maximum effective energy storage density of PBLZST ceramics at 1.94 J/cm3 is obtained when x = 0.35, and their energy storage efficiency is 81.9%, which confirms that they are the potential materials in the pulse energy storage components.

Photoetchable glasses (PEGs) have been widely used in three-dimensional integrated circuits as interposers. However, the high costs associated with laser through-hole technology have limited their utilization in high-frequency circuitry and packaging. Ultraviolet lithography may reduce the cost and improve through-hole properties allowing PEGs to become a preferred practice and lend them to wider usage. Herein, we investigate the viability of PEGs by systematically studying the structural, compositional, and morphological properties of their through-hole composite structures as a function of several key process parameters including exposure energy and annealing conditions. Results indicate that both exposure energy and annealing temperature and duration have compensating effects. Optimized through-glass vias (TGVs) were determined to result from an annealing temperature of 560 °C, an annealing time of 60 min, and an exposure energy of 6 J/cm2. Metallization of through-holes was carried out using magnetron sputtering of an adhesion layer of Ti followed by a Cu layer. The morphology and composition of through-hole metallization, analyzed by electron microscopy and energy dispersive X-ray spectroscopy, revealed surfaces to have sharp, well-defined edges with smooth surfaces. The proposed PEG interposer processing methodologies described here offer renewed optimism for the efficient fabrication of channels and through-vias for microfluidic and integrated circuits and other three-dimensional electronic and hybrid systems.

Relatively high dielectric loss often limits the widespread utilization of photoetchable glasses (PEG) in three-dimensional system packaging. Herein, we present the influence of B-doping on network structures and dielectric properties of a Li-Al-Si-based PEG. The addition of B is found to markedly reduce the dielectric losses over the VHF-UHF bands making these PEGs more suitable for applications. Moreover, the effect of UV exposure on structural transformations is studied by X-ray diffraction and Raman spectroscopy. At a B2O3 additive content of 2 wt.-%, the average dielectric loss and dielectric constant are found to be 0.005 and 4.57, respectively, before UV exposure. However, these values decrease to 0.0015 and 3.65, respectively, after UV exposure and thermal annealing. The annealing temperature of PEG can be adjusted based on crystallization temperature since the stability of the boron trihedra are higher than that of the silicon-oxygen tetrahedra. Overall, it is determined that the use of B2O3 as an additive is effective in altering the dielectric properties of photosensitive glass making the PEGs more suitable for low loss three-dimensional system packaging for use over VHF and UHF bands.

Photoetchable glasses (PEG) are widely used as interposers in radio frequency electronic systems. However, high dielectric losses limit the utilization of PEGs in three-dimensional integrated microsystems. Herein, the internal structure of PEGs is shown to be altered by the addition of Al2O3 and its influence on dielectric properties systematically studied by X-ray diffraction, Raman spectroscopy and FT-infrared spectroscopy (FTIR). The Al2O3 content significantly influences the ring structure and an amount equal to 4 wt% results in a high degree of crystallinity and phase purity of lithium metasilicate. Lastly, a dielectric constant of 5.1 and dielectric loss of 3 × 10-3 were obtained at 1 GHz, which is attributed to weakened structural vibrations, without loss to attractive etching properties.

Li2O-Al2O3-SiO2 (LAS) photostructurable glasses (PSGs) are promising substrate materials with excellent three-dimensional shaping control. In this study, we prepared SrO-doped LAS-PSGs with different SrO content. The effect of SrO content on the dielectric and mechanical properties of the LAS-PSGs was investigated by deconvoluting (four-component) their Raman bands. The LAS-PSG sample with 1 wt% SrO exhibited enhanced mechanical properties: the enhanced surface micro-hardness of 568.20 HV, and the improved flexural strength of 157.23 MPa while maintaining a low dielectric loss of 4.1 × 10−3. These improvements of mechanical properties can be attributed to the increased relative fraction of Q3 units (Qn: n bridging oxygen bonds in a [SiO4] tetrahedral unit) in this sample. This is due to Q3 units being able to enhance the network structure of LAS-PSGs with little effect on [SiO4] tetrahedral units connections.

Photostructurable Li2O-Al2O3-SiO2 glass is a promising material to fabricate complex three-dimensional structure with a high aspect ratio. However, its high dielectric loss at high frequencies has restrained its application in the field of integrated circuits packaging. In this research, La2O3, which has a large ionic radius, as well as strong polarization and bonding strength, was used to obstruct mobile ion migration to reduce the dielectric loss. The results indicated that moderate doping with La2O3 could effectively reduce the dielectric loss. When the dopant amount was 3%, the dielectric loss was successfully reduced to a minimum of 4 × 10−3 with a dielectric constant of 6.6 at 1 GHz, and this sample also possessed the optimal dielectric-temperature stability. Additionally, the effects of doping on the photosensitivity and crystallization behavior were also analysed. The results suggested that La2O3 doping did not affect the photosensitivity and selective crystallization characteristics. However, La2O3 restrained the precipitation of silicate from the [SiO4] tetrahedron, resulting in a decrease of nucleation rate and a delay of crystallization.

The Li-Al-Si photoetchable glass (PEG) easily forms a complex three-dimensional (3D) structure, which is promising as an interposer in 3D integrated microsystems. However, its dielectric loss is rather large (~10 −2 @ 1 GHz), which inhibits the corresponding application in radio frequency (RF) microsystems. In this paper, the enhancement of dielectric properties caused by of Ca doping on the microstructure of the Li-Al-Si photoetchable glass system was investigated. The structure and performance were analyzed through X-ray diffraction (XRD), Mid-infrared spectroscopy analysis (MIR), Raman spectroscopy and impedance analysis. The results demonstrated that a significant modification in the dielectric properties were obtained with dielectric loss of 3 × 10 −3 . The reason was attributed to the decreased number of the non-oxygen bridge, which makes the structure more stable. Using hydrofluoric (HF) etching, through glass vias with a diameter of 117 µm were obtained.

Photoetchable glasses (PEGs) are widely used in integrated circuits as interposers. However, the high dielectric losses intrinsic of PEGs limit their applications in three-dimensional system packaging. Doping with alkaline earth oxides changes the network structure of the PEG, restricting migration of cations, and reducing structural and conduction losses in the glass. After UV exposure and annealing, the dielectric constant and dielectric loss decreases to 4.1 and 0.0025, respectively. Doping with alkaline earth oxides does not significantly decrease the glass transition temperature or viscous flow properties and thus the preferred use of PEGs as interposers. The breakdown filed strength of PEGs can reach 112 kV/cm, which increases their utility and range of applications. Analyses by X-ray diffraction and Raman spectroscopy reveal that alkaline earth oxides form polyhedra resulting in more complex glass networks. A small number of alkaline earth oxides can reduce their dielectric loss. Overall, the introduction of alkaline earth oxides improves their dielectric properties and breakdown filed strength, making PEGs more suitable as VLSI interposers.

In current three-dimensional (3D) radio frequency (RF) package field, the silicon interposer can’t entirely meet the needs of the package because of its non-negligible dielectric loss. Similarly, the application of through Glass vias (TGV) has restriction for the same reason. Therefore, this paper focuses on reducing dielectric loss of photoetchable glass (PEG), as well as the performance of TGV technology of PEG for packaging. The PEG was reduced in the dielectric loss by the addition of ZnO. The reduction in dielectric loss is due to changes in structure. The structure of PEG was analyzed through the XRD and the Raman spectroscopy. The dielectric performance was verified by the Impedance Analyzer. The result indicated dielectric loss obviously decreased to 0.0035 by ZnO doped and the reason primarily attributed to the decrease number of the Non-Oxygen-Bridge in the glass network and the structure is more stable. Through thermal processes and etching, the average diameter obtained around 75μm by TGV, and the aperture ratio of up to 25: 1, TGV density can reach 10000 / cm2.