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Dual Contact Metal Level Trench Resistor

IP.com Disclosure Number: IPCOM000181694D
Original Publication Date: 2009-Apr-09
Included in the Prior Art Database: 2009-Apr-09
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Abstract

A dual contact metal level trench resistor built using back end metallization levels is described. By forming the resistor with a novel concentric trench design, a 2X shrink is achieved compared to standard planar resist designs.

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Dual Contact Metal Level Trench Resistor

High precision resistor components are a necessary requirement for RF system design. Planar resistors built in the back end metallization levels are well known, but new solutions to shrink the footprint of these components are highly desireable due to ever increasing complexity and miniaturization at the system level. Compared to planar resistor geometries, our invention provides a greater than 2X shrink by using a novel concentric trench geometry.

A trench resistor structure is formed in at least 2 metallization levels and contacted by a third. Thin resistor materials separated by dielectrics are formed in a self-aligned concentric geometry using liner depositions and subsequent etch treatments. A novel outer electrode tab design allows for a single mask to be used and is thus equivalent to existing planar process flows in this aspect. With this trench resistor design, the current path starts at the top metal level, has an intermediate location at the bottom of the trench, and ends back up at the top metal level, thus allowing for greater than 2X the resistance compared to it's planar equivalent.

Figure 1. Schematic of orthogonal cross-sections of concentric trench design including contact tab to connect with outer electrode.

Figure 2. Illustration of resistance values showing greater than twice the num...