Method of inspecting holes using charged-particle beam
AssigneeJEOL Ltd.
InventorsNaoki Kikuchi, Tsutomu Negishi, Yuki Ono
Life of this patent
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Abstract
This disclosure is directed to a method of inspecting how contact holes or via holes are formed in a sample, such as a wafer. An electron beam is directed to the contact holes in succession. An absorbed current flowing through the sample is detected by a current amplifier. Data about the obtained absorbed current is stored in a memory. The electric current flowing through a reference sample and ground is measured, and the relation of the current to the etch depths of contact holes into the substrate is previously found. A control unit compares data about the measured current with the previously found relation and determines the depths of holes of interest into the substrate (i.e., inspects how they are etched).
Claims20
A method of finding the depth of a hole in an etched layer in a semiconductor substrate sample using a charged-particle beam, comprising the steps of:
- irradiating the hole with the charged-particle beam;
- detecting an electric current flowing between the substrate sample and ground as a result of the irradiation;
- and
- finding the etch depth of said hole in the substrate sample, based on a previously found relation of the current flowing between holes in a reference sample and ground to the depths of holes in said reference sample.
A method of inspecting a hole in an etched layer in a semiconductor substrate sample using a charged-particle beam, comprising the steps of:
- irradiating the hole with the charged-particle beam;
- detecting an electric current flowing between the inspected sample and ground as a result of the irradiation;
- and
- finding how the hole in the inspected sample is etched, based on previously found relations of the current flowing between holes in a reference sample and ground to remaining film thickness in the holes in said reference sample.
A method of inspecting a hole using in an etched layer in a semiconductor substrate sample a charged-particle beam, comprising the steps of:
- irradiating the hole with the charged-particle beam;
- detecting an electric current flowing between the inspected substrate sample and ground as a result of the irradiation;
- comparing the detected electric current with an electric current that is previously found using a reference sample flowing between the reference sample and ground where the hole is precisely etched;
- and
- judging that the hole in the inspected sample is precisely etched if the two currents agree, that the hole is overetched if the detected electric current is greater than the previously found current, and that the hole is underetched if the detected current is smaller than the previously found current.
A method of finding the depths of holes in an etched layer in a semiconductor substrate sample using a charged-particle beam, comprising the steps of:
- irradiating a region containing the holes with the charged-particle beam;
- detecting an electric current flowing between the inspected sample and ground as a result of the irradiation;
- repeating these steps for plural regions previously established on the inspected sample;
- obtaining data about a distribution of etch depths of the holes in the inspected sample in the substrate, based on the detected current and on a previously found relation of detected current flowing between the reference sample and ground to etch deaths of the holes into the substrate;
- and
- displaying a map based on the obtained data about the distribution of etched depths on a display unit.
A method of finding the depths of holes in an etched layer in a semiconductor substrate sample using a charged-particle beam, comprising the steps of:
- irradiating a region containing the holes with the charged-particle beam;
- detecting an electric current flowing between the inspected sample and ground as a result of the irradiation;
- repeating these irradiating and detecting steps for plural regions previously established on the inspected sample;
- obtaining data about a distribution of etch depths of the holes in the inspected sample in the substrate, based on the detected current and on a previously found relation of electric current flowing between a reference sample and ground to etch depths of the holes into the substrate and also on a previously found relation of the electric current flowing between the reference sample and ground to remaining film thicknesses in the holes;
- and
- displaying a map on a display unit, based on data obtained about the distribution of degrees of etching in the holes in the inspected sample.
A method of inspecting holes using a charged-particle beam, comprising the steps of:
- preparing a reference sample precisely etched;
- preparing an unknown sample that is not known whether it has been etched precisely or not;
- irradiating a region of said reference sample containing holes with the charged-particle beam;
- detecting an electric current flowing between the reference sample and ground;
- repeating these irradiating and detecting steps for plural preselected regions on said reference sample;
- irradiating a region of said unknown sample containing holes with the charged-particle beam;
- detecting an electric current flowing between the unknown sample and ground;
- repeating these irradiating and detecting steps for plural preselected regions on said unknown sample;
- finding data about current distributions on the reference sample and on the unknown sample;
- creating graphs indicative of the characteristics of the currents flowing through the regions of the reference sample and unknown sample;
- and
- displaying said graphs side by side on a display unit.
Dependencies are inferred from the claim text.