3D Semiconductor Defect Detection via Serial Wafer Etching
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Solution Overview
Problem
Current semiconductor inspection equipment is unable to detect defects in the deep portions of highly-integrated three-dimensional semiconductor structures, as it primarily provides two-dimensional information.
Innovation Solution
A system and method that involves etching the entire surface of a wafer at a consistent rate to expose successive surfaces, using modules like ion beam milling, CMP, dry etching, and wet etching, and analyzing modules such as SEM, XPS, and EDX to obtain two-dimensional information, which is then serialized to generate a three-dimensional image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current semiconductor inspection equipment is used to obtain two-dimensional information, then the inspection process is simple and fast, but defects in deep portions of three-dimensional patterns cannot be detected
Solution Approach 1:
The inspection process is segmented into multiple sequential steps: (1) etching the wafer surface to a specific depth, (2) obtaining two-dimensional images of the exposed surface, (3) repeating the etching and imaging process at different depths, and (4) stacking the two-dimensional images to reconstruct three-dimensional information. This segmentation enables detection of deep defects by breaking down the complex three-dimensional inspection task into manageable two-dimensional steps.
Solution Approach 2:
The patent transitions from two-dimensional surface inspection to three-dimensional internal inspection by introducing the depth dimension through sequential etching. Two-dimensional images obtained at different etching depths are stacked to create three-dimensional information, enabling detection of defects located at various depths within the semiconductor structure.
2Loss of information
If the entire surface of the wafer is repeatedly etched to expose successive surfaces for analysis, then three-dimensional information can be obtained, but the inspection time and process complexity increase
Solution Approach 1:
The etching process is performed in advance to predetermined depths before imaging. By pre-etching the wafer surface to specific depths and then obtaining images of the exposed surfaces, the system prepares the sample in advance for optimal imaging conditions, enabling efficient capture of three-dimensional information without requiring complex real-time processing.
Solution Approach 2:
The inspection process maintains continuity by sequentially repeating the etching and imaging cycles without interruption. The etching module continuously removes material layer by layer, and the analyzing module continuously captures images at each depth stage, ensuring uninterrupted acquisition of three-dimensional information throughout the inspection process.
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 the detection of defects and failures in three-dimensional semiconductor structures by creating detailed three-dimensional images from serially stacked two-dimensional data, improving inspection efficiency and accuracy.
Implementation Method 1
a milling apparatus for irradiating the entire surface of the wafer with an ion beam
Implementation Method 2
a wet etching apparatus
Implementation Method 3
a chemical mechanical polishing (CMP) apparatus
Implementation Method 4
a scanning electron microscope (SEM)
Implementation Method 5
an X-rays photoelectron spectroscopy (XPS)
Implementation Method 6
Energy Dispersive X-ray analysis (EDX)
Data Source
AI summary
A method for analyzing a semiconductor device includes repeatedly etching an entire surface of a wafer at a same etch rate by a target depth to expose a next surface of the wafer. The method includes obtaining two-dimensional structure information from each repeatedly etched surface of the wafer and serially stacking the repeatedly obtained two-dimensional structure information to generate a three-dimensional image.