Anomalous stress effects in ultra-thin silicon chips on foil

Author

Hassan, Mahadi-Ul ; Rempp, Horst ; Hoang, Tu ; Richter, Harald ; Wacker, Nicoleta ; Burghartz, Joachim N.

Author_Institution

Inst. for Microelectron. Stuttgart (IMS CHIPS), Stuttgart, Germany

fYear

2009

Firstpage

1

Lastpage

4

Abstract

Apparently anomalous and transient piezoresistive effects are observed from CMOS transistors and diffused resistors fabricated on 20 Â¿m thin, flexible chips for system-in-foil (SiF) applications. We show that this effect results from a transformation of uniaxial to biaxial stress according to the Poisson ratio of the visco-elastic epoxy glue used for chip attachment. This effect is further analyzed through current mirror circuits composed of orthogonally oriented transistors.

Keywords

MOSFET; elemental semiconductors; flexible electronics; internal stresses; microfabrication; piezoresistive devices; resistors; silicon; system-in-package; thin film circuits; viscoelasticity; CMOS transistors; Poisson ratio; Si; anomalous stress effects; biaxial stress; current mirror circuits; diffused resistors; flexible chips; foil; orthogonally oriented transistors; size 20 mum; system-in-foil applications; transient piezoresistive effects; ultrathin silicon chips; uniaxial stress; viscoelastic epoxy glue; Circuits; Microelectronics; Mirrors; Piezoresistance; Resistors; Semiconductor device measurement; Silicon; Stress measurement; Strips; Testing;

fLanguage

English

Publisher

ieee

Conference_Titel

Electron Devices Meeting (IEDM), 2009 IEEE International

Conference_Location

Baltimore, MD

Print_ISBN

978-1-4244-5639-0

Electronic_ISBN

978-1-4244-5640-6

Type

conf

DOI

10.1109/IEDM.2009.5424302

Filename

5424302