High density composite mim capacitor with reduced voltage dependence in semiconductor dies

Abstract

According to a disclosed embodiment, a composite metal-insulator-metal (MIM) capacitor includes a lower electrode of a lower MIM capacitor in a lower interconnect metal layer of a semiconductor chip. The composite MIM capacitor also includes an upper electrode of the lower MIM capacitor, the upper electrode of the lower MIM capacitor is located in a lower interlayer dielectric, wherein the lower interlayer dielectric separates the lower interconnect metal layer from the upper interconnect metal layers. A lower electrode of the upper MIM capacitor is located in the upper interconnect metal layer. The upper electrode of the upper MIM capacitor is located within the upper interlayer dielectric, which in turn is located on the upper interconnect metal layer. The upper electrode of the lower MIM capacitor is connected to the lower electrode of the upper MIM capacitor, and the lower electrode of the lower MIM capacitor is connected to the upper electrode of the upper MIM capacitor.

Description

technical field [0001] The present invention generally relates to the field of semiconductor manufacturing. More specifically, the invention relates to the field of fabrication of capacitors in semiconductor chips. Background technique [0002] High-performance mixed-signal and RF circuits require densely integrated capacitors. Metal-insulator-metal ("MIM") capacitors may be considered for use in the fabrication of integrated mixed-signal and RF circuits on semiconductor chips. Disadvantageously, conventional MIM capacitors have low capacitance density, and since RF and mixed-signal applications require high capacitance values, conventional MIM capacitors occupy too much chip area, resulting in increased chip cost for manufacturers and users. [0003] The capacitance value of a conventional MIM capacitor at an applied voltage can be expressed by Equation 1 below: [0004] C(V)=C 0 (1+aV+bV 2 ) (Equation 1) where C 0 is the capacitance value of the capacitor when the vo...

AI Technical Summary

Problems solved by technology

In conventional MIM capacitors, when the dielectric thickness is reduced to increase the capacitance density, the voltage coefficient of the MIM capacitor unfavorably increases

Thus, the undesired increase in the voltage coefficient of conventional MIM capacitors when reducing the dielectric thickness, and the large chip area occupied by the MIM capacitor plates, are significant disadvantages in using MIM capacitors for mixed-signal and RF applications

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