Method and apparatus for measuring the topography of a semiconductor device
AssigneeMotorola, Inc.
InventorsN. David Theodore, Juan P. Carrejo
Life of this patent
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Abstract
The topography of a surface is measured by utilizing a probe (10, 20) having a variable flexibility and a conductive tip (14, 16). Using the conductive tip (14, 16), a first tunneling current is measured at a first point (36). The tip (14, 16) is moved to a second point (37) and a deflection force is measured. The measurements from the different points (36, 37, 38, 39, 40, 41) are combined to provide composite images of the surface's topography and material composition.
Claims25
A method of measuring the topography of a semiconductor device comprising:
- providing a semiconductor device having a surface;
- providing a variable flexibility probe having a tip projecting perpendicularly from a first surface of the variable flexibility probe wherein the variable flexibility probe is electrically coupled to a scanning tunneling microscope;
- establishing a first stiffness of the variable flexibility probe;
- placing the tip at a first point that is a first distance above the surface;
- applying a tunneling voltage between the tip and the surface;
- measuring a first tunneling current;
- moving the tip to a second point that is in a plane wherein the plane includes the first point and is substantially parallel to the semiconductor device;
- measuring a second tunneling current;
- returning the tip to the first point;
- removing the tunneling voltage;
- establishing a second stiffness of the variable flexibility probe wherein the second stiffness is less than the first stiffness;
- moving the tip perpendicularly toward the surface to a third point on the surface;
- measuring a first repulsive force;
- moving the tip to a fourth point on the surface wherein the fourth point is displaced perpendicularly toward the surface from the second point;
- measuring a second repulsive force;
- moving the tip to a fifth point on the surface;
- and
- measuring a third repulsive force.
A method of determining the topography of a surface comprising:
- providing a surface;
- providing a variable flexibility probe having a conductive tip wherein the variable flexibility probe includes a force element for varying a stiffness of the variable flexibility probe;
- positioning the conductive tip at a first point above the surface;
- measuring a first tunneling current;
- moving the conductive tip to a second point on the surface;
- and
- measuring a first deflection.
A variable flexibility probe for use in measuring the topography of a semiconductor device comprising:
- a silicon nitride bar having a first end attached to a support member wherein the silicon nitride bar is cantilevered from the support member, the silicon nitride bar having a tip projecting from a first surface;
- a reference element having a first end attached to the support member wherein the reference element is cantilevered from the support member and is in a plane parallel to the silicon nitride bar;
- and
- a capacitor force element having a first plate of the capacitor attached to a second surface of the silicon nitride bar and a second plate of the capacitor attached to a first surface of the reference element.
A variable flexibility probe for use in making scanning tunneling microscopy and atomic force microscopy measurements of a surface comprising:
- a variable stiffness element having a first end attached to a support member wherein the variable stiffness element is cantilevered from the support member;
- a conductive tip projecting perpendicularly from a first surface of the variable stiffness element wherein the conductive tip is used for making the scanning tunneling microscopy measurement of the surface;
- and
- a force means for applying a varying force to the variable stiffness element for the purpose of changing a stiffness of the variable stiffness element for making the atomic force microscopy measurements.
Dependencies are inferred from the claim text.