Substrate Peripheral Cleaning and Optical Detection
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Solution Overview
Problem
The existing substrate polishing technologies face challenges in effectively cleaning the peripheral portions of semiconductor wafers, leading to residual debris that can contaminate device surfaces, and the use of particle counters for detection is limited by sensitivity issues, causing unnecessary detection of LPD and inability to fully assess cleanliness, resulting in potential PID defects.
Innovation Solution
A substrate processing method and apparatus that includes a polishing stage using abrasive tapes, followed by a cleaning stage with a two-fluid jet nozzle and a non-abrasive tape with a sensor to assess cleanliness by reflected light intensity, allowing for immediate verification and re-cleaning of the peripheral substrate areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a particle counter is used to detect cleanliness, then detection sensitivity is improved, but false detection of LPD increases and central portion cannot be observed
Solution Approach 1:
A transparent tape is introduced as an intermediary medium between the substrate and the light source/sensor. The tape is pressed onto the substrate peripheral portion, and light transmission through the tape is measured. This intermediary allows direct contact with the substrate surface while enabling optical detection, solving the problem of particle counters being unable to observe the central portion and causing false LPD detections.
Solution Approach 2:
The patent replaces the mechanical particle counter system with an optical transmission detection system. Instead of using a particle counter that requires sample extraction and mechanical counting, the invention uses light transmission through a transparent tape to detect particles, eliminating the limitations of the particle counter approach.
2Manufacturing precision
If conventional polishing is performed, then peripheral portion is polished, but particles are attached onto the substrate
Solution Approach 1:
The harmful polishing particles are extracted and removed from the substrate surface using a cleaning liquid jet. The cleaning liquid is supplied to the peripheral portion to dissolve and remove the polishing debris that was attached during the polishing process, separating the harmful particles from the substrate.
Solution Approach 2:
The patent uses cleaning liquid, which can include oxidizing agents, to chemically react with and remove polishing debris. The cleaning liquid accelerates the removal of particles through chemical oxidation, effectively eliminating the harmful factors generated during polishing.
3Ease of manufacture
If substrate is transferred to cleaning unit, then particles are cleaned, but follow-up cleaning is still needed after polishing
Solution Approach 1:
The cleaning function is merged with the polishing apparatus by integrating a cleaning liquid supply mechanism directly into the polishing device. This allows the cleaning process to be performed immediately after polishing within the same apparatus, eliminating the need for separate cleaning units and reducing follow-up cleaning time.
Solution Approach 2:
The cleaning action is performed preliminarily immediately after polishing, before the substrate is transferred to subsequent processing steps. By cleaning the peripheral portion right after polishing, the patent prevents particle contamination from affecting later processes, eliminating the need for follow-up cleaning.
4Productivity
If peripheral portion is not cleaned, then yield is improved, but contamination risk increases
Solution Approach 1:
The patent implements a feedback mechanism where light transmission through the transparent tape is measured to detect particles on the substrate peripheral portion. Based on this detection result, the system can determine whether additional cleaning is needed, providing feedback control to ensure yield improvement while minimizing contamination risk.
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
This approach enables reliable cleaning and verification of the peripheral substrate areas, reducing the risk of contamination and PID defects, thereby improving yield and reducing follow-up cleaning time and work, while preventing adverse effects on device surfaces.
Implementation Method 1
a two-fluid jet nozzle configured to clean the peripheral portion of the substrate by supplying a jet flow of a mixed fluid of a liquid and a gas
Implementation Method 2
applying light to the tape which has been brought into contact with the peripheral portion of the substrate and receiving reflected light from the tape
Implementation Method 3
a polishing tape having abrasive grains against the peripheral portion of the substrate
Data Source
AI summary
A substrate processing method which can clean a peripheral portion of a substrate after polishing and can check the cleaning effect of the peripheral portion of the substrate is disclosed. The substrate processing method includes polishing a peripheral portion of the substrate by pressing a polishing tape having abrasive grains against the peripheral portion of the substrate with a first head, cleaning the peripheral portion of the substrate by supplying a cleaning liquid to the peripheral portion of the substrate after polishing, bringing a tape having no abrasive grains into contact with the peripheral portion of the substrate after cleaning by a second head, applying light to the tape and receiving reflected light from the tape by a sensor, and judging that the peripheral portion of the substrate is contaminated when an intensity of the received reflected light is lower than a predetermined value.