Test key layout for detecting via-open failure
AssigneeUnited Microelectronics Corp.
InventorsChe-Kai Chan, Chao-Hui Huang
Life of this patent
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Abstract
A test key layout for finding open-via failures using an electron beam. Two types of test key layouts are designed. A first test key layout is used for finding open vias underneath even-numbered metallic layers while a second test key layout is used for finding open vias underneath odd-numbered metallic layers. A pair of neighboring metallic layers forms a group that has no direct electrical connection with other groups. The upper metallic layer in each group is in an open circuit state so that image contrast is enhanced.
Claims8
A test key layout for finding via-open failures, comprising:
- a first test key layout for finding open vias underneath even-numbered metallic layers, wherein the first test key layout includes a substrate, a first plurality of vias, a plurality of metallic layers over a substrate such that all even-numbered metallic layers are in an open circuit state, and the first plurality of vias is within a dielectric layer underneath an even-numbered metallic layer but above an odd-numbered metallic layer;
- and
- a second test key layout for finding open vias underneath odd-numbered metallic layer, wherein the second test key layout includes a substrate, a second plurality of vias, a plurality of metallic layers over the substrate such that all even-numbered metallic layers are in a closed circuit state, and the second plurality of vias is within a dielectric layer underneath an odd-numbered metallic layer but above an even-numbered metallic layer.
A test key layout for finding via-open failures, comprising:
- a substrate;
- a plurality of metallic layers over the substrate, wherein every pair of neighboring metallic layers forms a group that has no direct electrical connection with other groups, and an upper metallic layer of each group is in an open circuit state;
- and
- a plurality of vias between the metallic layers in each group.
Dependencies are inferred from the claim text.