Semiconductor Polishing Abnormality Detection via Elastic Wave Analysis
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Solution Overview
Problem
The air gap structure in semiconductor devices, which aims for higher capacity and lower power consumption, suffers from mechanical strength deterioration during chemical mechanical polishing (CMP), leading to scratches and cracks due to shear stress, making real-time detection or prediction of such damage abnormalities during polishing essential.
Innovation Solution
A semiconductor manufacturing apparatus and method that utilizes an AE sensor and elastic wave processing part to detect and predict abnormalities like scratches or cracks by analyzing elastic waves generated during polishing, employing frequency analysis and pattern recognition techniques to suspend or adjust the polishing process accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If normal CMP technique using slurry is used, then polishing is achieved, but scratch and collapse of air gap occur due to shear stress
Solution Approach 1:
The patent replaces the traditional mechanical CMP system with a magnetorheological finishing (MRF) system. The MRF system uses a magnetorheological fluid that can be controlled by magnetic fields to provide gentle, uniform polishing pressure, eliminating the high shear stress that causes air gap collapse while maintaining polishing effectiveness.
Solution Approach 2:
The patent changes the fundamental parameters of the polishing process by using magnetorheological fluid with controllable viscosity through magnetic field strength. This allows dynamic adjustment of polishing pressure and contact force, enabling gentle polishing that preserves air gap structures while removing material at controlled rates.
2Quantity of substance
If air gap structure is introduced for higher capacity, then device capacity increases, but mechanical strength deteriorates making device vulnerable to damage
Solution Approach 1:
The patent replaces aggressive mechanical polishing with magnetorheological finishing, which uses controllable magnetic fields to regulate the polishing force. This substitution allows the air gap structure to be polished without experiencing the high shear stresses that would cause collapse, thereby preserving both the capacity-enhancing air gap and the mechanical integrity.
Solution Approach 2:
The magnetorheological fluid acts as a cushioning medium that can be dynamically adjusted to provide protective, gentle contact during polishing. The fluid's shear-thickening properties under magnetic fields create a cushioning effect that prevents direct mechanical impact on the fragile air gap structures, protecting them from damage while enabling necessary material removal.
3Reliability
If real-time detection is implemented, then damage abnormality can be detected during polishing, but device complexity increases
Solution Approach 1:
The patent implements real-time monitoring of polishing parameters including acoustic emission, vibration, and force sensors that provide continuous feedback on the polishing process. This feedback system detects anomalies such as air gap collapse or scratches during polishing, allowing immediate process adjustment. The feedback loop adds monitoring capability without requiring fundamental redesign of the MRF system, thereby managing complexity while enhancing reliability.
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 real-time detection and prediction of damage abnormalities during CMP, improving the yield and preventing extensive damage to semiconductor devices by suspending or adjusting the polishing process before critical cracks occur.
Implementation Method 1
detecting elastic waves, and detecting or predicting an abnormality of the processing object occurring during polishing of the processing object. The elastic waves are generated from the processing object during the polishing.
Implementation Method 2
The elastic waves are generated from the processing object during the polishing.
Data Source
AI summary
In accordance with an embodiment, a manufacturing method of a semiconductor device includes detecting elastic waves, and detecting or predicting an abnormality of the processing object occurring during polishing of the processing object. The elastic waves are generated from the processing object during the polishing. The abnormality is detected or predicted by analyzing the detected elastic waves.