CMP Scraping Fixture and Conductor for Slurry Removal
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) processes rely solely on centrifugal force for slurry removal, leading to ineffective used slurry replacement and electrochemical corrosion of metal structures due to accumulated electric charges.
Innovation Solution
Incorporation of scraping fixtures that scrape used slurry off the polishing pad during rotation, with a conductor to ground the pad and discharge electric charges, ensuring timely removal and preventing corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centrifugal force alone is used for slurry removal, then the structure is simple, but used slurry replacement is ineffective and electrochemical corrosion occurs
Solution Approach 1:
The patent combines multiple slurry removal mechanisms (centrifugal force from pad rotation, scraping action from fixtures, and conductor-based charge discharge) into a unified slurry removal system. This integrated approach ensures thorough used slurry elimination while preventing electrochemical corrosion, thereby improving CMP reliability without excessive complexity increase.
Solution Approach 2:
The scraping fixtures act as intermediary elements between the rotating pad and the slurry removal process. These fixtures provide the mechanical scraping action that complements centrifugal force, enabling effective used slurry removal. The conductor elements serve as intermediaries to discharge accumulated electric charges, preventing electrochemical corrosion of metal structures.
2Reliability
If scraping fixtures are added to remove used slurry, then slurry replacement effectiveness improves, but device complexity increases
Solution Approach 1:
The scraping fixtures are designed to be passively actuated by the rotation of the polishing pad itself. As the pad rotates, it automatically brings the slurry into contact with the scraping fixtures, which then scrape off the used slurry without requiring additional active driving mechanisms. This self-service approach improves slurry removal effectiveness while minimizing the increase in device complexity.
3Object-affected harmful factors
If conductor is added to ground the pad, then electrochemical corrosion is prevented, but device complexity increases
Solution Approach 1:
The conductor elements are designed to utilize the naturally accumulated electric charges during CMP processing and convert this potentially harmful effect into a beneficial discharge mechanism. By providing a conductive path to ground, the system safely dissipates accumulated charges that would otherwise cause electrochemical corrosion, transforming a harmful byproduct into a controlled protective function.
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
Enhances CMP reliability and control by preventing slurry mixing and electrochemical damage, suitable for metal, dielectric, and polysilicon planarization processes.
Implementation Method 1
with a conductor to ground the pad and discharge electric charges
Implementation Method 2
Existing chemical mechanical polishing (CMP) processes rely solely on centrifugal force for slurry removal
Data Source
AI summary
Embodiments of apparatus and method for chemical mechanical polishing (CMP) are disclosed. In an example, an apparatus for CMP includes a platen, a slurry supply, and at least one scraping fixture. The platen is configured to rotate a pad thereon about a central axis of the pad. The slurry supply is configured to supply a slurry onto the pad while the pad rotates. The at least one scraping fixture is configured to scrape the slurry off the pad when the slurry travels a distance between the slurry supply and the at least one scraping fixture in a circumferential direction of the pad as the pad rotates.