Finite element modeling of temporary bonding systems for flexible microelectronics fabrication

Jesmin Haq, Bryan D. Vogt, Gregory Raupp, Doug Loy

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

One promising route to enable the manufacture of flexible microelectronics is through temporary bonding-debonding of flexible plastic substrates to rigid carriers, which facilitates effective substrate handling by automated tools. Understanding the thermomechanical properties of the temporary bonding system (flexible substrate-adhesive-carrier) could allow for improved control of bow and distortion of the flexible substrate that can adversely impact device fabrication. In this study, a thermomechanical analysis of this temporary bonding system is performed using finite element modeling (ANSYS) to understand how to control the stress-induced bow of the bonded system. This stress is developed during high temperature processing predominately through thermal mismatches between the carrier and substrate. However, viscous flow of adhesive can relax some stress to decrease the total extent of bowing of the bonded system. Interestingly, the viscoelasticity of flexible plastic substrate appears to be critical to the stress-induced bowing; viscous flow of the plastic substrate relaxes some stress of the bonded system and must be taken into account to achieve good agreement between simulated and experimental bow. By variation in the relaxation time (τ) and the relative relaxation modulus (α) of the adhesive, the simulation shows a limited range for the relaxation parameters over which the bow can be tuned for a specified carrier-flexible substrate system. These results suggest that further engineering of the adhesive is unlikely to dramatically decrease the bow of the bonded system as would be necessary for extension to large form sizes. Therefore, efforts should focus on new flexible substrates and rigid carriers; the model developed here can be utilized as a screening tool for this purpose.

Original languageEnglish (US)
Pages (from-to)18-25
Number of pages8
JournalMicroelectronic Engineering
Volume94
DOIs
StatePublished - Jun 2012
Externally publishedYes

Fingerprint

microelectronics
Microelectronics
Fabrication
fabrication
bows
Substrates
adhesives
Adhesives
Bending (forming)
plastics
viscous flow
Viscous flow
Plastics
viscoelasticity
Debonding
Viscoelasticity
Relaxation time
Screening
screening
relaxation time

Keywords

  • ANSYS
  • Finite element analysis
  • Flexible electronics
  • Viscoelasticity

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

Cite this

Finite element modeling of temporary bonding systems for flexible microelectronics fabrication. / Haq, Jesmin; Vogt, Bryan D.; Raupp, Gregory; Loy, Doug.

In: Microelectronic Engineering, Vol. 94, 06.2012, p. 18-25.

Research output: Contribution to journalArticle

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