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Simultaneously forming deep trench isolation and deep trench capacitor on the same chip

IP.com Disclosure Number: IPCOM000198808D
Publication Date: 2010-Aug-17
Document File: 3 page(s) / 52K

Publishing Venue

The IP.com Prior Art Database

Abstract

This invention provides a method and structure for forming an integrated circuit comprising DTCap and DTI on the same chip with following features: DTCap and DTI have same trench opening – process cost/complexity reduction DTCap has a thin dielectric on trench sidewall and a buried plate DTI has a thick dielectric on trench sidewall and has no buried plate

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Simultaneously forming deep trench isolation and deep trench capacitor on the same chip

DTI becomes necessary for 22nm bulk CMOS to improve well isolation. Deep trench formation is process consuming and costly.

Deep trench (DT) technology has been used to make capacitors and memories. Significant process cost reduction by forming DTI and DTCap (DT capacitors).

However, there are Challenges of forming DTCap and DTI on the same chip. For example, DTCap and DTI have competing requirements. DTCap needs a heavily doped plate (buried plate) while DTI cannot have buried plate to prevent electrical shorts. Furthermore, DTCap needs thin dielectric on trench sidewall to enhance capacitance while DTI needs thick dielectric to improve isolation.

This invention provides a method and structure for forming an integrated circuit comprising DTCap and DTI on the same chip with following features:
DTCap and DTI have same trench opening - process cost/complexity reduction DTCap has a thin dielectric on trench sidewall and a buried plate
DTI has a thick dielectric on trench sidewall and has no buried plate.

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An exemplary structure of a CMOS structure with DTI and DT

C

Contacts to wells and FETs are well-known in the art and not show

PFET NFET DT Capacit

STI

DTI

STI

DTI

STI

STI

S

N-well P-well

DT Cap

Deep N-well

Deep N-well

N+

P-sub

Buried plate

Prior art

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US6885080

In US6885080, DTCap and DTI on the same chip. However, in thi patent DTCap and DTI has same node...