CMP Polishing Apparatus Sensor Head Cleaning Nozzle
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Solution Overview
Problem
The abrasive grains and polishing debris in the CMP process tend to adhere to the optical sensor head, leading to inaccurate film thickness measurements due to decreased reflected light intensity.
Innovation Solution
A polishing apparatus is designed with a sensor-head cleaning nozzle that emits a cleaning liquid to the optical sensor head, preventing abrasive grains and debris from adhering and ensuring accurate film thickness measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the light path is filled with transparent liquid to stabilize film thickness measurement, then measurement stability is improved, but abrasive grains and polishing debris adhere to the optical sensor head, causing measurement inaccuracy
Solution Approach 1:
The patent extracts the harmful abrasive grains and polishing debris from the light path by introducing a cleaning mechanism. A cleaning nozzle positioned near the optical sensor head emits cleaning liquid to remove accumulated debris, separating the harmful particles from the measurement environment while maintaining the transparent liquid filling the light path for stable measurements.
Solution Approach 2:
The cleaning liquid acts as an intermediary substance that facilitates the removal of abrasive grains and polishing debris from the optical sensor head. This intermediary cleaning liquid flows through the cleaning nozzle to physically remove harmful particles, enabling both stable measurement conditions and accurate film thickness measurement.
2Productivity
If abrasive grains and polishing debris are present in the polishing liquid, then polishing function is maintained, but they adhere to the optical sensor head and decrease reflected light intensity
Solution Approach 1:
The patent converts the harmful accumulation of abrasive grains and polishing debris on the optical sensor head into a beneficial cleaning process. By positioning a cleaning nozzle to emit cleaning liquid at the sensor head, the system transforms the problem of debris accumulation into an active cleaning mechanism that maintains light path clarity and reflected light intensity.
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 cleaning liquid flow from the sensor-head cleaning nozzle effectively prevents abrasive grains and debris from adhering to the optical sensor head, thereby maintaining accurate film thickness measurements in the CMP process.
Implementation Method 1
a sensor-head cleaning nozzle configured to emit a cleaning liquid to the optical sensor head
Implementation Method 2
an optical film-thickness measuring system configured to direct light onto the workpiece and receive reflected light from the workpiece by an optical sensor head
Implementation Method 3
produce a spectrum of the reflected light from intensity of the reflected light
Data Source
AI summary
A polishing apparatus capable of preventing abrasive grains in a polishing liquid and polishing debris of a workpiece from adhering to an optical sensor head and capable of improving a measuring accuracy of a film thickness of a workpiece is disclosed. The polishing apparatus includes: a polishing table configured to support a polishing pad having a through-hole; a polishing head configured to press a workpiece against the polishing pad; an optical film-thickness measuring system having an optical sensor head disposed below the polishing pad; and a sensor-head cleaning nozzle configured to emit a cleaning liquid to the optical sensor head. The sensor-head cleaning nozzle is disposed in the polishing table and points at the optical sensor head.