CMP Apparatus with Real-Time Thickness Monitoring
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Solution Overview
Problem
Conventional chemical mechanical polishing processes lack real-time monitoring of silicon wafer thickness, leading to uneven polishing and increased wafer scrap rates due to worn polishing pads, which reduces production yield and increases manufacturing costs.
Innovation Solution
A chemical mechanical polishing apparatus and method that includes a polishing zone with a film-thickness measuring module to monitor the wafer thickness in real-time, allowing for adjustments in polishing parameters and timely replacement of the polishing pad to maintain uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If real-time thickness monitoring is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements real-time feedback by installing a thickness monitoring device that continuously measures wafer thickness during polishing and transmits data to a control system. The control system automatically adjusts polishing parameters based on the measured thickness, forming a closed-loop feedback control system that maintains thickness uniformity while managing device complexity through automated control.
Solution Approach 2:
The patent replaces manual inspection and mechanical measurement methods with non-contact optical or electromagnetic thickness measurement technology. This substitution allows for real-time, non-intrusive thickness monitoring during the polishing process, improving measurement accuracy without significantly increasing mechanical complexity.
2Productivity
If polishing pad is used until wear occurs, then productivity is maintained, but manufacturing precision deteriorates
Solution Approach 1:
The thickness monitoring device provides continuous feedback on wafer thickness uniformity during polishing. When the system detects that thickness uniformity is deteriorating due to pad wear, it automatically alerts operators or adjusts polishing parameters, enabling timely pad replacement before significant quality degradation occurs, thus maintaining both productivity and precision.
Solution Approach 2:
The system performs preliminary detection of thickness variations during the polishing process, allowing operators to replace the polishing pad proactively before it causes significant defects. This preliminary action prevents the deterioration of manufacturing precision while minimizing interruptions to productivity.
3Device complexity
If no real-time monitoring is used, then device complexity is reduced, but loss of information increases
Solution Approach 1:
The control system receives real-time thickness data from the monitoring device and uses this feedback to automatically adjust polishing parameters such as downforce, speed, or slurry flow rate. This closed-loop feedback ensures that critical thickness information is captured and acted upon, preventing information loss while managing system complexity through automated control algorithms.
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
The solution improves the yield of polished wafers by ensuring uniform thickness, reducing waste, and lowering production costs through real-time thickness monitoring and adaptive polishing control.
Implementation Method 1
the film-thickness measuring module is used for measuring the thickness of the wafer
Implementation Method 2
the polishing module is located in the polishing zone, including a polishing belt extended along a second direction that is perpendicular to the first direction, and the polishing belt is able to move along the second direction
Data Source
AI summary
A chemical mechanical polishing apparatus includes a polishing zone having a wafer entrance and a wafer exit, first wafer platform, polishing module, slurry injection module, polishing cleaning module, and film-thickness measuring module. The first wafer platform includes a wafer loading region, and is able to move from the wafer entrance to the wafer exit along a first direction. The polishing module is located in the polishing zone, including a polishing belt extended along a second direction perpendicular to the first direction and is able to move along the second direction. The slurry injection module is configured for injecting slurry towards a wafer to-be-polished by the polishing module. The polishing cleaning module is located on one side of the polishing module along the first direction for cleaning the wafer. The film-thickness measuring module is located on another side of the polishing module along the first direction for measuring the thickness of the wafer.