Title :
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
Abstract :
Apparently anomalous and transient piezoresistive effects are observed from CMOS transistors and diffused resistors fabricated on 20 ¿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;
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
DOI :
10.1109/IEDM.2009.5424302
