Test structure macro for monitoring dimensions of deep trench isolation regions and local trench isolation regions
Embodiments are directed to a method Embodiments are directed to a test structure of a fin-type field effect transistor (FinFET). The test structure includes a first conducting layer electrically coupled to a dummy gate of the FinFET, and a second conducting layer electrically coupled to a substrate of the FinFET. The test structure further includes a third conducting layer electrically coupled to the dummy gate of the FinFET, and a first region of the FinFET at least partially bound by the first conducting layer and the second conducting layer. The test structure further includes a second region of the FinFET at least partially bound by the second conducting layer and the third conducting layer, wherein the first region comprises a first dielectric having a first dimension, and wherein the second region comprises a second dielectric having a second dimension greater than the first dimension.
1. A method of forming a test structure of a fin-type field effect transistor (FinFET) formed in an active region of a substrate, the method comprising:
forming a first conducting layer;
electrically coupling the first conducting layer to a dummy gate of the FinFET;
forming a second conducting layer;
electrically coupling the second conducing layer to a first isolation region of the substrate, wherein the first isolation region electrically isolates the FinFET from other devices of the active region of the substrate;
electrically coupling the second conductive layer to a second isolation region of the substrate, wherein the second isolation region electrically isolates the active region of the substrate from another active region of the substrate;
forming a third conducting layer; and
electrically coupling the third conducting layer to the dummy gate of the FinFET;
wherein the formation of the first conducing layer and the second conducting layer define boundaries of the first isolation region of the substrate;
wherein the formation of the second conducting layer and the third conducting layer define boundaries of the second isolation region of the substrate;
measuring a first capacitance between the first conducting layer and the second conducting layer;
measuring a second capacitance between the second conducting layer and the third conducting layer;
classifying a type of the first isolation region as a local shallow trench isolation (STI) type or a deep STI type based on a magnitude of the first capacitance; and
classifying a type of the second isolation region as a local STI type or a deep STI type based on a magnitude of the second capacitance;
wherein the local STI type comprises a local STI type depth dimension;
wherein the deep STI type comprise a deep STI type depth dimension;
wherein the local STI type depth dimension is less than the deep STI type depth dimension.
2. The method of claim 1 , wherein the electrical coupling of the first conducing layer to the dummy gate comprises a first local interconnect and a first via.
3. The method of claim 1 , wherein the electrical coupling of the second conducting layer to the first isolation region of the substrate or the second isolation region of the substrate comprises a second local interconnect and a second via.
4. The method of claim 1 , wherein the electrical coupling of the third conducting layer to the dummy gate comprise a third local interconnect and a third via.
5. The method of claim 1 further comprising determining that the local STI type depth dimension varies from a predetermined design target for the local STI type depth dimension.
6. The method of claim 5 further comprising determining that the deep STI type depth dimension varies from a predetermined design target for the deep STI type depth dimension.