Polish Pad Conditioning via Off-Center Dynamic Positioning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional mechanical polishing systems, such as CMP, fail to provide uniform conditioning of polishing pads due to limitations in the configuration of conditioning pads, leading to non-uniform polishing of substrates, as the conditioning pad's size and movement do not adequately match the polishing pad's size and rotation, resulting in reduced contact and increased particulate introduction.
Innovation Solution
The selection of a conditioning pad diameter based on the equation dc—pad≦rp—pad−dsub, where dc—pad is the conditioning pad diameter, rp—pad is the polishing pad radius, and dsub is the substrate diameter, ensures continuous contact and improved uniformity by defining an annular region width sufficient to cover the substrate, allowing the conditioning pad to move between positions that expose the polishing pad to both primary rotational directions, enhancing polishing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional conditioning pad is used in mechanical polishing systems, then the polishing process can proceed, but uniform conditioning of the polishing pad is not achieved, leading to non-uniform polishing results
Solution Approach 1:
The invention changes the geometric parameters of the conditioning pad system by defining a specific annular region width (W) that is sufficient to cover the substrate diameter, and positioning the conditioning pad at multiple discrete locations around the polishing pad perimeter. This parameter optimization ensures that the conditioning pad can effectively condition the entire polishing pad surface in a uniform manner, directly resolving the non-uniform conditioning issue.
Solution Approach 2:
The invention introduces dynamic positioning of the conditioning pad head, which can move between multiple discrete locations around the polishing pad. This dynamic capability allows the conditioning pad to systematically cover different regions of the polishing pad during operation, ensuring uniform conditioning across the entire surface and eliminating the static limitation of conventional single-position conditioning systems.
2Reliability
If the conditioning pad size and movement are not properly matched to the polishing pad size and rotation, then the polishing process can continue, but contact between the conditioning pad and polishing pad is insufficient, increasing particulate introduction
Solution Approach 1:
The invention optimizes the geometric parameters by defining the annular region width (W) to be sufficient for covering the substrate diameter, and positions the conditioning pad at multiple discrete locations strategically arranged around the polishing pad. This parameter optimization ensures continuous and adequate contact between the conditioning pad and polishing pad surface, preventing particulate generation from insufficient conditioning.
3Area of stationary object
If a larger conditioning pad is used to cover more area, then conditioning coverage improves, but the ability to move between positions that expose the polishing pad to both primary rotational directions is reduced
Solution Approach 1:
The invention segments the conditioning coverage area into multiple discrete annular regions, each associated with a specific conditioning pad location. Instead of using one large conditioning pad that would restrict movement, the system uses multiple smaller conditioning zones positioned around the polishing pad perimeter. This segmentation allows the conditioning function to be distributed across multiple positions, maintaining both adequate coverage area and positioning flexibility for exposing the polishing pad to different rotational directions.
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 results in significantly improved polishing uniformity, reducing defect densities and extending the lifespan of the polishing pad by maintaining continuous contact and uniform conditioning, as demonstrated by reduced dielectric thickness variation across the substrate surface.
Implementation Method 1
a pad conditioner is used to abrade the top surface of the polishing pad
Implementation Method 2
applying a contacting surface of at least one conditioning pad against the polishing pad
Data Source
AI summary
A mechanical polishing apparatus includes a polishing pad, at least one carrier head positioned over and off center relative to the polishing pad and configured for holding at least one substrate against the polishing pad within a first annular region of the polishing pad when the polishing pad is rotating. At least one conditioning head is positionable over and off center relative the polishing pad at a plurality of first positions and configured for applying a contacting surface of at least one conditioning pad against the polishing pad when the polishing pad is rotating, where the conditioning pad is applied to a second annular region of the polishing pad and moves between the plurality of first positions. In the apparatus, the diameter of the conditioning pad≦a difference between a radius of the polishing pad and a width of the first annular region.