High-R Poly Resistance Deviation Improvement from Suppressions of Back-End Mechanical Stresses

Tingyou Lin, Yingchieh Ho*, Chau-Chin Su

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

This paper investigates techniques for N-Type high-resistance polysilicon resistors to reduce the resistance deviation which is caused by the back-end mechanical stress. In the back-end layers of the wafer, a top metal thickness equal to 3μm is provided to increase the heat allowing current density in the metal routes of power ICs. The top metal processing yields the mechanical stress to increase the resistance by the piezoresistance effect. To eliminate the mechanical stresses, a new layout is proposed with the full passivation cutting (FPC). The resistor with an FPC uses the passivation film separation to create a physical empty room for suppressing the mechanical stresses on the polysilicon. The proposed layout has been verified in the 0.4-μm bipolar-CMOS-DMOS process, and the resistance shifts were compared with other four-Type layouts. Compared to those original layouts, the proposed layout exhibits the improvements in the resistance deviation reduction in the maximum ratio 20.80%.

Original languageEnglish
Article number8026567
Pages (from-to)4233-4241
Number of pages9
JournalIEEE Transactions on Electron Devices
Volume64
Issue number10
DOIs
StatePublished - 1 Oct 2017

Keywords

  • Full passivation cutting (FPC)
  • mechanical stress
  • N-Type high resistance(high-R) polysilicon(NHRPO)

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