Apparatus for high speed ROM cells
A ROM cell comprises a first first-level contact formed on a first active region of a transistor of a memory cell, a second first-level contact formed on a second active region of the transistor of the memory cell, wherein the second first-level contact is coupled to a first VSS line and a second VSS line formed in a first interconnect layer, wherein the second VSS line is electrically coupled to the first VSS line, and wherein the second VSS line is of a direction orthogonal to a direction of the first VSS line. The ROM cell further comprises a first bit line formed in the first interconnect layer, wherein the first bit line is formed in parallel with the second VSS line and a second bit line formed in the first interconnect layer, wherein the second bit line is formed in parallel with the second VSS line.
1. A device comprising:
a fin structure over a substrate;
a gate wrapping the fin structure around three sides of the fin structure;
a first VSS line in a contact layer overlying the substrate;
a first bit line in a first interconnect layer overlying the contact layer;
a second bit line in the first interconnect layer, wherein the second bit line is in parallel with the first bit line;
a word line in a second interconnect layer overlying the first interconnect layer; and
a word line strap structure comprising:
a gate contact in the contact layer;
a first via in the first interconnect layer:
a first metal line in the first interconnect layer, wherein the first metal line is over the first via; and
a second via in the second interconnect layer, wherein the word line is over the second via.
2. The device of claim 1 , wherein:
the fin structure comprises a drain, a source and a channel coupled between the drain and the source.
3. The device of claim 2 , wherein:
the source is connected to the first VSS line; and
the drain is coupled to the first bit line through a coding layer.
4. The device of claim 3 , wherein:
the coding layer is formed by a first contact and a first via, and wherein the first via is in the first interconnect layer and underneath the first bit line.
5. The device of claim 1 , further comprising:
a second VSS line in the first interconnect layer, wherein the second VSS line is parallel with the first bit line.
6. The device of claim 5 , further comprising:
a third VSS line in the second interconnect layer, wherein the third VSS line is electrically coupled to the second VSS line.
7. The device of claim 6 , wherein:
the third VSS line is in parallel with the word line.
8. A memory cell comprising:
a memory transistor comprising a drain, a source, a gate, and a channel coupled between the drain and the source;
a first VSS line in a contact layer overlying a substrate;
a first bit line in a first interconnect layer overlying the contact layer;
a second bit line in the first interconnect layer, wherein the second bit line is in parallel with the first bit line;
a second VSS line in the first interconnect layer, wherein the second VSS line is in parallel with first bit line;
a word line in a second interconnect layer overlying the first interconnect layer;
a third VSS line in the second interconnect layer, wherein the third VSS line is in parallel with the word line; and
a word line strap structure coupled between the gate and the word line.
9. The memory cell of claim 8 , wherein the word line strap structure comprises:
a gate contact in the contact layer;
a first via in the first interconnect layer:
a first metal line in the first interconnect layer, wherein the first metal line is over the first via; and
a second via in the second interconnect layer, wherein the word line is over the second via.
10. The memory cell of claim 8 , wherein:
the second VSS line is electrically coupled to the first VSS line through a first via in the first interconnect layer.
11. The memory cell of claim 8 , wherein:
the third VSS line is electrically coupled to the second VSS line.
12. The memory cell of claim 8 , wherein:
the drain is electrically coupled to the first bit line; and
the source is electrically coupled to the first VSS line.
13. The memory cell of claim 8 , wherein:
the word line is of a direction orthogonal to a direction of the first bit line.
14. An apparatus comprising:
a plurality of interconnect structures over a substrate;
a gate in a contact layer over the substrate;
a first VSS line in the contact layer;
a first bit line in a first interconnect layer over the contact layer;
a second bit line in the first interconnect layer, wherein the second bit line is in parallel with the first bit line;
a second VSS line in the first interconnect layer, wherein the second VSS line is orthogonal to the first VSS line;
a word line in a second interconnect layer over the first interconnect layer;
a third VSS line in the second interconnect layer, wherein the third VSS line is in parallel with the word line; and
a word line strap structure coupled between the gate and the word line.
15. The apparatus of claim 14 , wherein:
the first bit line is orthogonal to the first VSS line; and
the second bit line is orthogonal to the first VSS line.
16. The apparatus of claim 14 , further comprising:
a drain, a source and channel between the drain and the source.
17. The apparatus of claim 16 , wherein:
the drain is connected to the plurality of interconnect structures through a first contact and a second contact formed in the contact layer; and
the gate is connected the plurality of interconnect structures through a third contact formed in the contact layer.
18. The apparatus of claim 17 , wherein:
a height of the gate is equal to a height of the first contact.
19. The apparatus of claim 17 , wherein:
a height of the second contact is equal to a height of the third contact.
20. The apparatus of claim 14 , wherein the word line strap structure comprises:
a gate contact in the contact layer;
a first via in the first interconnect layer:
a first metal line in the first interconnect layer, wherein the first metal line is over the first via; and
a second via in the second interconnect layer, wherein the word line is over the second via.