Experimental study on ultrasonic stress relief for cured SU-8 photoresist layer

Du, Liqun; Wang, Qijia

doi:10.1016/j.mee.2010.07.005

Cited by 8 publications

(2 citation statements)

References 13 publications

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“…The curing process of epoxy adhesive is the key procedure affecting the properties of cured products [ 5 ]. As a common field auxiliary method, ultrasonic is used in the epoxy curing process to improve energy utilization and reduce curing time as well as manufacturing costs [ 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Study on Curing Kinetics and the Mechanism of Ultrasonic Curing of an Epoxy Adhesive

et al. 2022

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Ultrasonic curing is an effective way to enhance the curing extent of composite material bonding in the aerospace industry. The non-thermal effect of ultrasonic has been revealed to improve curing efficiency. However, the mechanism of the ultrasonic non-thermal effect is still not clear. In this work, a variable activation energy model of ultrasonic curing was established by utilizing the iso-conversional method, including the activation energy of the thermal effect and activation energy of the non-thermal effect. The thermal effect caused by ultrasonic was accurately peeled off. An obvious decrease in activation energy was found from 54 kJ/mol in thermal curing to 38 kJ/mol in ultrasonic curing. The activation energy of the reaction system in ultrasonic curing was substituted into the modified Kamal autocatalytic equation, and the parameters of the ultrasonic curing kinetic model were estimated by means of an ALO algorithm. Further discussion based on in situ FTIR showed that the non-thermal effect of ultrasonic can affect the vibration strength, stability, and chemical bond energy of internal groups, but cannot cause the fracture of chemical bonds. Moreover, frontier molecular orbital analysis showed that the chemical reactivity of epoxy/amine molecules increased and the HOMO–LUMO energy gap decreased from 6.511 eV to 5.617 eV under the effect of ultrasonic.

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Section: Introductionmentioning

confidence: 99%

Study on Curing Kinetics and the Mechanism of Ultrasonic Curing of an Epoxy Adhesive

et al. 2022

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“…John et al [6] revealed that the ultrasonic impact treatment can alleviate the tensile stress concentration and increase the fatigue strength. Further, Du et al [7] introduced the ultrasonic vibration aging method to reduce the residual stress in Ni electroforming layer and obtained a more effective removal with proper parameters. But, ultrasonic vibration with a long time usually causes fatigue damage.…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of stress release geometries on reducing residual stress in electroforming metal microstructure

Song

Zhao

et al. 2018

J. Micromech. Microeng.

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Micro electroforming, as a mature micromachining technology, is widely used to fabricate metal microdevices in micro electro mechanical systems (MEMS). However, large residual stress in the local positions of the micro electroforming layer often leads to non-uniform residual stress distributions, dimension accuracy defects and reliability issues during fabrication of the metal microdevice. To solve this problem, a novel design method of presetting stress release geometries in the topological structure of the metal microstructure is proposed in this paper. First, the effect of stress release geometries (circular shape, annular groove shape and rivet shape) on the residual stress in the metal microstructure was investigated by finite element modeling (FEM) analysis. Two evaluation parameters, stress concentration factor KT and stress non-uniformity factor δ were calculated. The simulation results show that presetting stress release geometries can effectively reduce and homogenize the residual stress in the metal microstructures were measured metal microstructure. By combined use with stress release geometries of annular groove shape and rivet shape, the stress concentration factor KT and the stress non-uniformity factor δ both decreased at a maximum of 49% and 53%, respectively. Meanwhile, the average residual stress σavg decreased at a maximum of 20% from −292.4 MPa to −232.6 MPa. Then, micro electroforming experiments were carried out corresponding to the simulation models. The residual stresses in the metal microstructures were measured by micro Raman spectroscopy (MRS) method. The results of the experiment proved that the stress non-uniformity factor δ and the average residual stress σavg also decreased at a maximum with the combination use of annular groove shape and rivet shape stress release geometries, which is in agreement with the results of FEM analysis. The stress non-uniformity factor δ has a maximum decrease of 49% and the average residual stress σavg has a maximum decrease of 37% from −257.0 MPa to −162.0 MPa.

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Stress reduction method in fabrication of a multi-scale inertial switch with ultra-high aspect ratio

Chen

Tao

et al. 2016

Microsyst Technol

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Experimental study on ultrasonic stress relief for cured SU-8 photoresist layer

Cited by 8 publications

References 13 publications

Study on Curing Kinetics and the Mechanism of Ultrasonic Curing of an Epoxy Adhesive

Study on Curing Kinetics and the Mechanism of Ultrasonic Curing of an Epoxy Adhesive

Effectiveness of stress release geometries on reducing residual stress in electroforming metal microstructure

Stress reduction method in fabrication of a multi-scale inertial switch with ultra-high aspect ratio

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