Metal–Organic Frameworks: New Interlayer Dielectric Materials

Abstract

The design and synthesis of new interlayer dielectric (ILD) materials has been as ubjecto fi nterest in terms of their potential use in high-performance electronic devices.A ccording to Moore's law,t he number of active devices in an integrated circuit (IC) has been exponentially increasing, doubling approximately every 2years. [1] To keep pace with this rapidly advancing technology,t he performances of ICs can be enhanced by increasing transistor speed or reducing transistor size by packing more transistors onto ac hip. This decrease in size of the transistor also demands that the size of the interconnecting wires also be decreased. However,t his shrinking increases the resistance of the wires, which, in turn, reduces the speed of the ICs. These interconnecting wires, separated by av ery small ILD material, also increaset he capacitance between the wires, which resultsi nadelay and power loss in the ICs. By introducing low-dielectric-constant (low-k)I LD materials, problems associated with crosstalk between the interconnecting wires can be solved. [2] According to the International Te chnology Roadmap for Semiconductors (ITRS), in the nearf uture,p orousm aterials anda ir-gap structures will take the place of low-k materials by replacing SiO 2 as the ILD in multilevel interconnect schemes, thus substantially reducing the interconnection resistance/capacitance delay and electronics crosstalk in ICs. [3] As air or vacuums have the lowest dielectric constant (k), the partial replacement of solid materials with air or av acuum represents ap otential route to the development of new low-k ILD materials. It would permit porous materials to be used as low dielectric materials. Nevertheless, there are number of requirements for such new low-k materials, including thermal stability at temperatures of 400 8Co rh igher, electrically insulating, high mechanical strength,a nd good adhesion to neighboring layers. [4] Metal-organic frameworks (MOFs) with highly uniform porosities,u ltralow densities, high thermals tabilities, and easy tunability of the structuralp roperties have the potential to meet the above-mentioned demands for use as stable, low-k materials. [5] MOFs have been extensively studied over the past decadef or applications in gas storage, sensing, chemical separation, catalysis, drug delivery,b iomedical imaging, magnetic uses, optical applications,a nd in ferroelectrics. [6] However,t he dielectric properties of MOFs as an ew ILD materialh ave not been explored extensively,e ven thought hey possess the advantageousproperties of functioning as both inorganic and organic materials. Current theoretical and experimental results regarding low-k MOFs highlightt he bright future of MOFs as new ILD materials. Based on initial research, we propose aroadmap that can serve as as tarting point for addressing the potential use of MOFs as ILD materials in the microelectronics industry.K nowledge in this area is sufficient to stimulate researchersi nto investigating MOFs as ILD materials. Initial research on MOFs as ILD mate...

Structural, electronic, and dielectric properties of a large random network model of amorphous zeolitic imidazolate frameworks and its analogues

“…The miniaturization of electronic devices in integrated circuits, means that new ultra‐low dielectrics as insulating material are required to decrease cross‐talk, signal delays, and power losses in electronic components. Recent theoretical studies have estimated the dielectric constants for a series of MOFs, and the calculated results show that many MOFs have promising electronic and dielectric properties . These theoretical studies also encouraged the related experimental works to further investigate and confirm the dielectric and optical properties for both crystalline MOFs and ZIFs, such as HKUST‐1, MIL‐53(Al), Zn‐based MOF and ZIF‐8 .…”

Fluorous Metal–Organic Frameworks and Nonporous Coordination Polymers as Low‐κ Dielectrics

“…By first‐principle DFT calculations, Warmbier et al subsequently showed that the κ values reported in were underestimated by less than 10%. As far as it is known, promising experimental evidence of κ lower than 2.5 is still infrequent, manifested only by: a) the 2.33(±0.05) value of κ reported for ZIF‐8 thin films at 10 5 Hz stored under ambient conditions with estimated ≈60% relative humidity; b) the 2.4 value shown at 10 5 Hz by pellets of [Sr(1,3‐BDC)] (1,3‐H 2 bdc = benzene‐1,3‐dicarboxylic acid); and c) the 1.2 and 2.1 values reported for films of MOF‐3 and MOF‐5 at 2 × 10 6 Hz, respectively . These authors claim that films of MOF‐5 are stable if exposed to water vapors, but they do not report κ measurements performed after exposure to humidity.…”

Semiconductor Metal–Organic Frameworks: Future Low‐Bandgap Materials

“…They provided a roadmap for the implementation of MOFs in microelectronics devices . A few reports on the dielectric behavior of MOFs as interlayer dielectrics components for integrated circuit design have also appeared . However, studies relating to the semiconducting behavior of MOFs are still in their initial stages, and further investigations are highly desired …”