Testing the quality of lift-off processes in wafer fabrication

A method of testing the quality of a lift-off process used to fabricate functional components on a wafer, the method comprising:

• fabricating a plurality of test components on the wafer along with the functional components, wherein the test components include at least one location where the lift-off process was performed to define a hole through an insulation layer to a first conductive layer, and where the hole was filled with conductive material of a second conductive layer;
• measuring a resistance between the first conductive layer and the second conductive layer in the hole of at least one of the test components;
• and
• determining the quality of the lift-off process used to fabricate the functional components on the wafer based on the measured resistance in the at least one test component.

A method of testing the quality of a lift-off process used to fabricate functional components on a wafer, the method comprising:

• fabricating a plurality of test components on the wafer concurrently with the functional components by:
• patterning a first conductive layer in a test component;
• forming resists on the first conductive layer in lift-off locations;
• depositing an insulation layer;
• performing a lift-off process to remove the insulation layer on top of the resists to form holes in the insulation layer corresponding with the lift-off locations;
• depositing conductive material for a second conductive layer to fill the holes in the insulation layer;
• and
• patterning the second conductive layer to form traces connecting the filled holes in series, which defines a test circuit in the test component.

A test component on a wafer of functional components, the test component comprising:

• a first conductive layer having a first pattern;
• an insulation layer formed on the first conductive layer, wherein a plurality of holes are formed in the insulation layer over the first conductive layer from a lift-off process used in the fabrication of the functional components;
• and
• a second conductive layer that fills the holes in the insulation layer, and that includes a second pattern defined to connect the filled holes in series between the first pattern of the first conductive layer and the second pattern of the second conductive layer.