US 12,165,931 B2Granted

Method and device for measuring semiconductor multilayer structure based on second harmonic

AssigneeShanghai Aspiring Semiconductor Equipment Co., Ltd.

InventorsChongji Huang, Weiwei Zhao, Puxi Zhou

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Abstract

A measuring method and device based on the second harmonic for the whole area measurement of a wafer comprises three modes: a fixed-point measurement, a scanning measurement, and a combination of the fixed-point measurement and the scanning measurement. The scanning measurement solution measures the entire wafer under the premise of ensuring high measurement efficiency, obtain the position, size and relative density distribution of electrical defects, and achieve locating and checking of abnormal points on the wafer. A new formula system is provided for describing the second harmonic signal, so that the actual measurement results and the theoretical model are unified under the three modes of the fixed-point measurement, the scanning measurement, and the combination of fixed-point measurement and scanning measurement, so that the second harmonic metrology technology is no longer only a qualitative analysis method, but also a quantitative analysis method.

Claims65

Dependent claims

A method for measuring a semiconductor multilayer structure based on second harmonic, the method comprising:

emitting a laser, by a light source, wherein the laser passes through an incident optical path system, forms a light spot on a sample, and injects photons into the sample to carry out a laser irradiation on the sample;
the sample is a detectable structure consisting of more than 2 layers of substance, at least one layer of the substance is a semiconductor layer, the light source reaches an interface to be probed;
the sample and the light spot have a relative movement on a plane, a relative movement speed of the relative movement is v, v≥0;
when the method enters a fixed-point measurement mode in which a specified measurement point is measured, v=0;
when the method enters a scanning measurement mode, v>0, a direction of the relative movement is a scanning direction, wherein, in the scanning measurement mode, a laser-induced charge distribution of the sample is uniform and a total duration of irradiation and a total number of said photons injected is the same for all measurement points on the sample;
during a scanning measurement process of a same batch of the sample, a shape and size of the light spot remain constant;
a power of the light source remains constant such that, when the shape and size of the light spot remain constant, a light intensity of the light spot also remains constant;
the relative moving speed of the sample and the light spot remains constant;
when the photon is absorbed by an electron and an internal charge distribution of the sample changes, a change curve of the second harmonic signal received by a signal receiver through an exit optical path system can be described as a second harmonic signal formula;
the second harmonic signal is a filtered light of a single wavelength, and an exit angle is the same as an incidence angle;
the change curve of the second harmonic signal, comprising the following information:
when entering the fixed-point measurement mode, the time variation characteristics of the second harmonic signal generated by the specified measuring point are recorded;
when entering the scanning measurement mode, the spatial distribution characteristics of the second harmonic signal generated by a scanning measuring point in the process of the relative movement are recorded.

10 more elements

A device for measuring a semiconductor multilayer structure based on second harmonic, the device comprising:

a light source configured to emit a laser, wherein the laser is configured to form a light spot on a sample through an incident optical path system and inject photons into the sample to carry out a laser irradiation on the sample;
the incident light path system is used to adjust beam parameters of the laser emitted by the light source;
the sample is a detectable structure with an interface composed of two or more layers of substances, at least one layer of the substance is a semiconductor layer, and the light source can reach an interface to be probed;
a carrier platform is used to carry and move the sample on a plane, and a speed of the plane movement is v, v≥0;
when the device enters a fixed-point measurement mode and the specified measurement point is measured, v=0;
when the device enters a scanning measurement mode, v>0, a direction of the plane moving is a scanning direction, wherein, in the scanning measurement mode, a laser-induced charge distribution of the sample is uniform and a total duration of irradiation and a total number of said photons injected is the same for all measurement points on the sample;
an exit optical path system is used to adjust second harmonic parameters of the outgoing second harmonic;
a signal receiving system is used to receive a second harmonic signal adjusted by the exit optical path system, a change curve of the second harmonic signal can be described as a second harmonic signal formula;
the change curve of the second harmonic signal, comprising the following information:
when entering the fixed-point measurement mode, the time varying characteristics of the second harmonic signal generated by the specified measuring point are recorded;
when entering the scanning measurement mode, the spatial distribution characteristics of the second harmonic signal generated by the scanning measuring point in the process of the relative movement are recorded;
a monitoring system is used for real-time monitoring of a running state of the device and sending real-time feedback information;
an input system is used to receive a user's input information in a human-computer interaction;
a display system is used for displaying an output information of the device in a human-computer interaction;
a central processing system is used for receiving the input information and the real-time feedback information, controlling the running of the device, processing the second harmonic signal according to the second harmonic signal formula, and outputting the output information;
wherein the device is configured such that, during a scanning measurement process of a same batch of the sample implemented by the device, a shape and size of the spot remain constant;
a power of the light source remains constant such that, that is, when the shape and size of the light spot remain constant, a light intensity of the light spot also remains constant;
the relative moving speed of the sample and the light spot remains constant.

15 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/272,126Filed 10 May 2022
Priority: CN 202210328447.631 Mar 2022
Published: US 2024/0038600 A11 Feb 2024
Granted: 10 Dec 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

H10P 74/207
Characterised by the properties tested or measured, e.g. structural or electrical properties: electrical properties, e.g. testing or measuring of…
G01N 21/636
Optically excited: using an arrangement of pump beam and probe beam; using the measurement of optical non-linear properties
G01N 21/8422
Systems specially adapted for particular applications: investigating thin films, e.g. matrix isolation method
G01N 21/9501
Characterised by the material or shape of the object to be examined: semiconductor wafers