CMP Polishing Pad Segmented Elements Void Cooling
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Solution Overview
Problem
Conventional chemical mechanical polishing (CMP) pads face challenges in maintaining effective polishing performance due to temperature increases from frictional heating, which can lead to irreversible chemical reactions and defects during the polishing of semiconductor wafers.
Innovation Solution
A CMP pad design featuring discrete polishing elements connected to a base pad by multiple supports, creating voids that allow for efficient fluid management and temperature control, while maintaining a high surface contact area and compliance with the substrate, thereby reducing thermal-induced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional polishing pad with continuous polishing surface is used, then polishing coverage is improved, but temperature increase from frictional heating worsens leading to defects
Solution Approach 1:
The polishing pad is segmented into discrete polishing elements (protrusions) separated by voids. This segmentation reduces the continuous contact area between the pad and substrate, thereby reducing frictional heating while maintaining adequate polishing coverage through the distributed arrangement of multiple polishing elements.
Solution Approach 2:
The polishing pad incorporates a porous structure with voids between polishing elements. These voids allow polishing fluid to flow through and provide cooling, reducing the temperature increase caused by frictional heating while maintaining polishing effectiveness.
2Reliability
If polishing elements are connected by multiple supports with spacing, then fluid management and cooling are improved, but structural complexity increases
Solution Approach 1:
The pad structure is divided into discrete polishing elements connected by supports, creating a modular design. This segmentation enables fluid to flow through the voids for effective cooling while maintaining a relatively simple overall structure that can be manufactured using conventional techniques.
Solution Approach 2:
The supports are strategically positioned to provide local structural reinforcement where needed, allowing the polishing elements to be spaced apart for cooling while maintaining adequate mechanical strength. The local placement of supports optimizes both cooling efficiency and structural integrity.
3Temperature
If discrete polishing elements are used with voids, then temperature control is improved, but polishing surface area contact is reduced
Solution Approach 1:
The polishing surface is segmented into discrete elements distributed across the pad. While each individual element has reduced contact area, the cumulative contact area of multiple distributed elements maintains adequate polishing coverage while the voids between them enable temperature control through fluid flow.
Solution Approach 2:
The polishing elements are arranged in a three-dimensional configuration with vertical protrusions from the base pad. This dimensional arrangement increases the effective polishing surface area through the height of the protrusions while maintaining void spaces for cooling, effectively adding a vertical dimension to the polishing contact.
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 design enhances polishing efficiency by maintaining lower temperatures, reducing defect generation, and improving conformation to the substrate, resulting in higher removal rates and reduced defectivity.
Implementation Method 1
temperature increases from frictional heating
Implementation Method 2
efficient fluid management and temperature control
Data Source
AI summary
A polishing pad useful in chemical mechanical polishing can comprise a base pad having a top surface and surface, a plurality of polishing elements each having a top polishing surface and a bottom surface, and wherein each of the plurality of polishing elements is connected to the top surface of the base pad to the polishing element by three or more supports wherein the bottom surface of the polishing element, the top surface of the base pad and the supports define a region comprising at least one void and there are openings between the three or more supports. Such pad can be used in a method by providing a substrate and polishing the substrate with the pad, optionally, with a polishing medium.