Semiconductor Wafer Inspection With Polarization End-Point Detection
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Solution Overview
Problem
Existing methods for identifying defects in semiconductor devices struggle with determining horizontal information of wiring layers and end points during milling processes, leading to inefficiencies and prolonged processing times due to the lack of real-time feedback on uniformity and end point detection.
Innovation Solution
An inspecting apparatus for semiconductor devices that utilizes a milling device to partially remove wafers with an ion-beam, combined with a measuring device that includes a polarization camera to measure polarization characteristics and uniformity of reflected light, allowing for real-time detection of end points and uniformity during the milling process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ion-beam milling devices are used to remove wiring layers, then the wiring layers can be removed, but it is difficult to determine the end point which results in relatively long processing time
Solution Approach 1:
The patent implements real-time optical feedback during the ion beam milling process. A light source irradiates the wiring layer surface, and an optical detector measures the reflected or transmitted light intensity. As the ion beam removes material, the optical properties of the exposed layers change, providing continuous feedback signals that indicate when the end point (target layer exposure) is reached, enabling precise control without prolonged processing.
Solution Approach 2:
The patent replaces the conventional mechanical/end-point-based milling control with an optical measurement system. Instead of relying on pre-programmed milling depths or mechanical sensors, the system uses optical detection (light reflection/transmission) to non-contactly monitor the milling process and determine the end point, substituting mechanical control with optical sensing.
2Loss of information
If related methods such as OES and SIMS are used to identify defective wiring layers, then some defect information can be obtained, but it is difficult to identify horizontal information of the wiring layer
Solution Approach 1:
The patent introduces light as an intermediary to probe the wiring layer structure. By irradiating the sample with light and detecting the optical response (reflection, transmission, absorption), the system obtains information about the horizontal structure and composition of the wiring layer without directly contacting or damaging the sample, complementing the vertical sectioning capability of ion beam milling.
3Manufacturing precision
If conventional methods are used for milling wiring layers, then the process can be completed, but there is no real-time feedback on uniformity which results in non-uniform removal across different wiring layers
Solution Approach 1:
The patent implements real-time optical feedback during the ion beam milling process. A light source irradiates the wiring layer surface, and an optical detector measures the reflected or transmitted light intensity. As the ion beam removes material, the optical properties of the exposed layers change, providing continuous feedback signals that indicate when the end point (target layer exposure) is reached, enabling precise control without prolonged processing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate identification of defects and uniform removal of wiring layers in real-time, reducing processing time and improving the efficiency of semiconductor device inspection.
Implementation Method 1
a lens assembly configured to introduce the incident light such that the incident light passes through the objective lens and the passing region and is emitted on the test wafer
Implementation Method 2
a polarization camera configured to scan the test wafer based on receiving reflected light reflected from the test wafer, wherein the measuring device is configured to measure a polarization characteristic of the reflected light
Implementation Method 3
an objective lens provided on the first end portion of the body portion
Implementation Method 4
a lens assembly including a plurality of optical filters and an optical splitter, the lens assembly being configured to introduce the incident light
Data Source
AI summary
Provided is an inspecting apparatus for semiconductor device including a chamber, a substrate stage within the chamber and configured to load a test wafer, the test wafer including a plurality of wiring layers, a milling device configured to partially remove the test wafer, and a measuring device including a body portion, a light source configured to irradiate an incident light, an objective lens, a lens assembly having a plurality of optical filter and an optical splitter, wherein the lens assembly is configured to introduce the incident light such that the incident light is emitted on the test wafer; and a polarization camera configured to scan the test wafer by receiving reflected light reflected from the test wafer, wherein the measuring device is configured to measure polarization characteristic of the reflected light and uniformity of the test wafer.