Reliability study of wafer bonding for micro-electro-mechanical systems

Almasri, Mahmoud; Altemus, Bruce; Gracias, Alison; Clow, Larry; Tokranova, Natalya; Castracane, James; Bai, Xu

doi:10.1117/12.524934

Cited by 3 publications

(4 citation statements)

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“…6. Details of the testing method are previously described in Almasri 15. Bonding was realized using films prepared by sonicating the nanoparticles directly in BCB.…”

Section: Resultsmentioning

confidence: 99%

“…The monomer divinylsiloxane bis‐benzocylobutene (DVS‐bisBCB) material forms a highly crosslinked network when the monomer undergoes a Diel–Alders cycloaddition reaction at temperatures above 225 °C 11. The crosslinked material has the following properties: low dielectric constant (2.65–2.5 (1 MHz–10 GHz)), low moisture absorption (<0.2%), high bonding strength (>50 MPa) and high chemical resistance to extended TMAH etch processes 12–16. It is supplied as a solution of B‐staged BCB monomers (46 wt.%) in mesitylene.…”

Section: Methodsmentioning

confidence: 99%

“…BCB exhibits a number of properties that are advantageous as an intermediate bonding layer, such as a low dielectric constant (∼2.65), high bond strength (>50 MPa) 15 and chemical resistance to TMAH 16. However, the disadvantage for the use of BCB as an intermediate layer is its poor thermal conductivity (±0.3 Wm −1 /K) that works as a thermal barrier to heat flow 17.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of diamond nanoparticles on the thermal properties of benzocyclobutene (BCB)

Gracias

Tokranova

Thelen

et al. 2010

Physica Status Solidi (a)

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This paper describes the influence of diamond nanoparticles on the modification of the thermal properties of benzocyclobutene (BCB) which is used for three‐dimensional (3D) wafer‐to‐wafer integration. Hybrid nanocomposites containing mixtures of 0.5–10 weight% (wt.%) diamond nanoparticles [average particle size (APS): 10 nm] in BCB were analyzed using thermal gravimetric analysis (TGA) and flash diffusivity techniques. Measurements show that the addition of nanoparticles significantly increases the decomposition temperature. Diffusivity measurements and subsequent calculations of thermal conductivity suggest that the inclusion of nanoparticles only slightly improves the conductivity.

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“…6. Details of the testing method are previously described in Almasri 15. Bonding was realized using films prepared by sonicating the nanoparticles directly in BCB.…”

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Influence of diamond nanoparticles on the thermal properties of benzocyclobutene (BCB)

Gracias

Tokranova

Thelen

et al. 2010

Physica Status Solidi (a)

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“…This in turn has led to a requirement for the fabrication of thin films and suitable wafer bonding techniques. However, in the wafer bonding process, a low temperature is essential to avoid dopant diffusion and a loss of interconnection strength in the microelectronic wafer [2]. Accordingly, Au-Si compound material has emerged as a promising solution for realizing high-strength bonds in IC components since it has a low eutectic temperature of 363 • C [3].…”

Section: Introductionmentioning

confidence: 99%

The effect of annealing temperature on the microstructure of nanoindented Au/Cr/Si thin films

Lee¹,

Liu²

2007

Nanotechnology

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The nano-mechanical properties of as-deposited thin Au/Cr films deposited on Si(100) substrates are investigated using a nanoindentation technique. Nanoindentation is performed to a maximum depth of 1000 nm, and selected specimens are then annealed at temperatures of 250, 350 or 450 °C for 2 min. The nanoindentation results show that the loading–unloading curve is continuous and smooth in both the loading and the unloading steps, which suggests that no debonding or cracking occurs. Furthermore, very little elastic displacement is observed in the unloading curve, which indicates that the deformation is primarily plastic in nature. The hardness and Young’s modulus of the Au/Cr/Si thin films are found to vary with the nanoindentation depth, and have values of 1.7 GPa and 88 GPa, respectively, at the maximum indentation depth of 1000 nm. The microstructures of the as-deposited and annealed nanoindented specimens are examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The microstructural observations reveal that nanoindentation induces an atomic reorganization, and results in the formation of high-stress plastic deformation regions beneath the indenter. In the as-deposited specimens, the plastic deformation results in a pile-up of Au around the entrance of the indentation. However, the diffusion of the Au atoms is enhanced at higher temperatures, and hence the annealing process prompts a homogenization of the high-stress areas and leads to a full recovery of the pile-up effect. The high temperature induced in the annealed thin film specimens also prompts a silicidation of the Cr layer, which results in a direct contact between the Au film and the Si substrate. As a result, annealing has a beneficial effect on the interfacial bond strength. Following annealing at the highest temperature of 450 °C, an Au–Si eutectic phase is formed, which further enhances the strength of the interfacial bond.

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Atomic layer deposited ultrathin metal nitride barrier layers for ruthenium interconnect applications

Dey

Yu²,

Consiglio³

et al. 2017

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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RC-time delay in Cu interconnects is becoming a significant factor requiring further performance improvements in future nanoelectronic devices. Choice of alternate interconnect materials, as for example, refractory metals, and subsequent integration with underlying barrier and liner layers are extremely challenging for the sub-10 nm nodes. The development of conformal deposition processes for alternate interconnects, liner, and barrier materials are crucial in order for implementation of a possible replacement for Cu interconnects for narrow line widths. In this study we report on ultra-thin (~ 3nm) chemical 2 vapor deposition (CVD) grown ruthenium films on 0.5 and 1 nm thick metal nitride (TiN, TaN) barrier layers deposited via atomic layer deposition (ALD). Using scanning electron microscopy, we determined the effect of the underlying barrier layer on the coverage of the ruthenium overlayer. We utilized synchrotron x-ray diffraction with in-situ rapid thermal annealing to investigate the thermal stability of the barrier layers and determine the effective activation energies of barrier failure leading to ruthenium monosilicide formation.For Ru films deposited directly on Si and on 0.5 nm MN (M=Ti, Ta) covered Si substrates, silicide formation proceeds via a two-step crystallization process involving lateral nucleation above ~ 440 °C followed by thickening of the ruthenium monosilicide layer above ~520 °C. This silicidation temperature of ~ 440 °C could be potentially problematic in back-end-of-the-line (BEOL) processing since it is close to the typical thermal budget used. However ~1 nm thick ALD MN (M=Ti, Ta) was found to be adequate to block silicide formation up to ~ 580 °C and ~ 620 °C for TiN and TaN, respectively, and also aided in superior coverage of the CVD ruthenium overlayer (>90%). The results reported here might be useful to ascertain annealing temperature and time for BEOL process and integration optimization without reaching a state where ruthenium silicides start forming.

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Reliability study of wafer bonding for micro-electro-mechanical systems

Cited by 3 publications

References 0 publications

Influence of diamond nanoparticles on the thermal properties of benzocyclobutene (BCB)

Influence of diamond nanoparticles on the thermal properties of benzocyclobutene (BCB)

The effect of annealing temperature on the microstructure of nanoindented Au/Cr/Si thin films

Atomic layer deposited ultrathin metal nitride barrier layers for ruthenium interconnect applications

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