Advanced Dielectric Materials (Polyimides and Polybenzoxazoles) for Fan‐Out Wafer‐Level Packaging (FO‐WLP)

Enomoto, Tetsuya; Matthews, Joel; Motobe, Takeharu

doi:10.1002/9781119313991.ch14

Cited by 10 publications

(3 citation statements)

References 17 publications

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“…Due to the high CTE of the dielectrics and weak grain boundaries In this study, the dielectric around the Cu-Cu bumps is mainly composed of UF. It can be replaced by PI, BCB, or other polymer dielectrics [45][46][47][48]. The CTE of these dielectrics is larger than that of Cu.…”

Section: Discussionmentioning

confidence: 99%

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Shie

Hsu

et al. 2021

Materials

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The failure mechanisms of Cu–Cu bumps under thermal cycling test (TCT) were investigated. The resistance change of Cu–Cu bumps in chip corners was less than 20% after 1000 thermal cycles. Many cracks were found at the center of the bonding interface, assumed to be a result of weak grain boundaries. Finite element analysis (FEA) was performed to simulate the stress distribution under thermal cycling. The results show that the maximum stress was located close to the Cu redistribution lines (RDLs). With the TiW adhesion layer between the Cu–Cu bumps and RDLs, the bonding strength was strong enough to sustain the thermal stress. Additionally, the middle of the Cu–Cu bumps was subjected to tension. Some triple junctions with zig-zag grain boundaries after TCT were observed. From the pre-existing tiny voids at the bonding interface, cracks might initiate and propagate along the weak bonding interface. In order to avoid such failures, a postannealing bonding process was adopted to completely eliminate the bonding interface of Cu–Cu bumps. This study delivers a deep understanding of the thermal cycling reliability of Cu–Cu hybrid joints.

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Section: Discussionmentioning

confidence: 99%

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Shie

Hsu

et al. 2021

Materials

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“…Low temperature cure dielectrics such as HD8900 Series are cured around 200 °C and thus are compatible with epoxy molding materials used in FO-WLP packages. These new low temperature cure dielectrics were also developed for markets like MRAM, RF, INFO, CMOS, MEMS, and backside RDL applications where the base substrate, other materials, or the device packages itself are temperature sensitive and require a low cure dielectric [3].…”

Section: Introductionmentioning

confidence: 99%

LITHOSCALE features accomplish dual exposure and high-resolution patterning

Varga,

Uhrmann,

Holly

et al. 2023

38th European Mask and Lithography Conference (EMLC 2023)

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“…The investigation is focused on the Cu diffusion barrier and low-k materials that are capable of blocking the Cu EM/diffusion and protecting the device to avoid uncertainty in performance [17][18][19][20][21][22]. Several low-k materials, which include silicon dioxide (SiO 2 ), polybenzoxazole (PBO), benzocyclobutane (BCB), and photosensitive polyimide (PSPI), have been used [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Thermal, Mechanical, and Electrical Stability of Cu Films in an Integration Process with Photosensitive Polyimide (PSPI) Films

Ustad,

Chavan,

Kim

et al. 2023

Nanomaterials

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Photosensitive polyimides (PSPIs) have been widely developed in microelectronics, which is due to their excellent thermal properties and reasonable dielectric properties and can be directly patterned to simplify the processing steps. In this study, 3 μm~7 μm thick PSPI films were deposited on different substrates, including Si, 50 nm SiN, 50 nm SiO2, 100 nm Cu, and 100 nm Al, for the optimization of the process of integration with Cu films. In situ temperature-dependent resistance measurements were conducted by using a four-point probe system to study the changes in resistance of the 70 nm thick Cu films on different dielectrics with thick diffusion films of 30 nm Mn, Co, and W films in a N2 ambient. The lowest possible change in thickness due to annealing at the higher temperature ranges of 325 °C to 375 °C is displayed, which suggests the high stability of PSPI. The PSPI films show good adhesion with each Cu diffusion barrier up to 350 °C, and we believe that this will be helpful for new packaging applications, such as a 3D IC with a Cu interconnect.

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Advanced Dielectric Materials (Polyimides and Polybenzoxazoles) for Fan‐Out Wafer‐Level Packaging (FO‐WLP)

Cited by 10 publications

References 17 publications

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

LITHOSCALE features accomplish dual exposure and high-resolution patterning

Thermal, Mechanical, and Electrical Stability of Cu Films in an Integration Process with Photosensitive Polyimide (PSPI) Films

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