CMP Retainer Flexure Eliminates Slurry Trapping Gap
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Solution Overview
Problem
In chemical mechanical polishing, the gap between the inner and outer rings of carrier heads can trap slurry or particulates, leading to defects such as scratching on the substrate being polished.
Innovation Solution
A retainer with an inner and outer section connected by a flexure, allowing the inner section to be vertically movable relative to the outer section, which reduces the likelihood of slurry trapping and enables adjustable polishing rates by controlling the pressure on the polishing pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a gap is provided between the inner and outer rings of carrier heads, then ease of assembly and structural flexibility are improved, but slurry or particulates can be trapped in the gap, causing scratching defects on the substrate
Solution Approach 1:
The patent removes the gap between the inner and outer rings by making the retainer a continuous structure without spaces, thereby eliminating the source of slurry trapping and preventing substrate scratching defects
Solution Approach 2:
The inner and outer sections of the retainer are merged into a single continuous structure, eliminating the gap that previously existed between separate components and preventing slurry accumulation
2Adaptability or versatility
If the inner section is made vertically movable relative to the outer section, then adjustable polishing rates and control over polishing pressure are improved, but device complexity increases
Solution Approach 1:
The retainer's inner section is designed to be dynamically movable relative to the outer section through vertical displacement, allowing adjustable polishing pressure and rate while maintaining structural simplicity through a straightforward mechanical design
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 design reduces polishing non-uniformity and defects by eliminating the gap between the inner and outer sections, allowing for consistent polishing and adjustable edge polishing rates without sacrificing control over the polishing process.
Implementation Method 1
a flexure coupling the inner section and the outer section such that the inner section is vertically movable relative to the outer section
Data Source
AI summary
A carrier head for chemical mechanical polishing includes a base, an actuator, a substrate mounting surface, and a retainer. The retainer includes an inner section and an outer section connected by a flexure. A bottom of the inner section of the retainer provides an inner portion of a lower surface configured to contact a polishing pad. An inner surface of the inner section extends upwardly from an inner edge of the lower surface to circumferentially surround the substrate mounting surface. The inner section of the retainer is positioned to receive a controllable load from the actuator and is vertically movable relative to the base. A bottom of the outer section of the retainer provides an outer portion of the lower surface. The outer section of the retainer is vertically fixed to the base. The inner section of the retainer is vertically movable relative to the outer section of the retainer.