Soft error resistant memory cell and method of manufacture
View Patent ↗A semiconductor device memory cell ( 100 ) can include a built-in capacitor for reducing a soft-error rate (SER). A memory cell ( 100 ) can include a first inverter ( 102 ) and second inverter ( 104 ) arranged in a cross-coupled configuration. A capacitor ( 110 ) can be coupled between a first storage node ( 106 ) and second storage node ( 108 ). A capacitor ( 110 ) can be a “built-in” capacitor formed with interconnect wirings utilized to connect memory cell circuit components.
1. A memory cell, comprising:
a first node for storing a first potential;
a second node for storing a second potential;
transistor gate electrodes formed from a gate layer; and
a capacitor having plates coupled between the first node and second node, a portion of one plate of the capacitor comprising a first interconnect wiring pattern that includes a plurality of conductive layers commonly etched into the same pattern with substantially aligned edges.
2. The memory cell of claim 1 , further comprising:
a first inverter having an input coupled to the first node and an output coupled to the second node; and
a second inverter having an input coupled to the second node and an output coupled to the first node; wherein
the first node stores a true data value and the second node stores a complementary data value.
3. The memory cell of claim 1 , further including:
a first access transistor coupled to the first node; and
a second access transistor coupled to the second node.
4. The memory cell of claim 1 , wherein:
the first interconnect wiring pattern includes a plurality of separate portions, each portion including bottom conductive layer, a dielectric layer formed over the bottom conductive layer, and a top conductive layer formed over the dielectric layer, the bottom conductive layer forming at least a portion of a first plate of the capacitor, the bottom conductive layer, dielectric layer, and top conductive layer having the same pattern.
5. The memory cell of claim 4 , further including:
a second conductive interconnect wiring formed over the first interconnect wiring pattern that forms at least a portion of a second plate of the capacitor.
6. The memory cell of claim 5 , wherein:
the second conductive interconnect wiring comprises titanium;
the bottom conductive layer comprises titanium nitride; and
the top conductive layer comprises titanium.
7. The memory cell of claim 1 , wherein:
the gate layer is not in physical contact with a drain of any transistor of the memory cell.
8. The memory cell of claim 1 , wherein:
the first interconnect wiring pattern includes
a first portion of the first interconnect wiring comprising a bottom conductive layer formed below a dielectric layer that isolates the bottom conductive layer from a top conductive layer, the bottom conductive layer electrically connecting drains of a first and second transistor of the memory cell.
9. A memory cell, comprising:
a first data storage node;
a second data storage node;
a capacitor comprising a first plate coupled to the first data storage node, a second plate coupled to the second data storage node, and a third plate separated from the first and second plates by a capacitor dielectric; and
a plurality of wiring portions, each comprising a commonly patterned first conductive layer and dielectric layer, a first wiring portion forming the first plate and a second wiring portion forming the second plate, the dielectric layer forming the capacitor dielectric.