CMP Polishing Pad Radial Temperature Control for Uniformity
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) techniques struggle with non-uniform temperature distribution across the polishing pad, leading to variations in removal rate, polishing uniformity, erosion, and residue, which affect within-wafer and wafer-to-wafer uniformity.
Innovation Solution
A dedicated temperature control system that delivers a temperature-controlled medium, such as liquid, vapor, or spray, onto the polishing pad surface, with multiple independently controlled dispensers spaced along the radius to provide radial temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional CMP process is used without dedicated temperature control, then the apparatus structure remains simple, but temperature variation across the polishing pad causes non-uniform removal rate and poor polishing uniformity
Solution Approach 1:
The temperature control system is segmented into multiple independent zones along the radius of the polishing pad. Each zone has its own dispenser that can independently deliver temperature-controlled medium, allowing localized temperature management to address radial temperature gradients and improve polishing uniformity across different regions of the substrate.
Solution Approach 2:
Different regions of the polishing pad are provided with different temperature control characteristics. The system delivers temperature-controlled medium to specific radial zones based on their individual thermal requirements, creating local quality variations in temperature management that compensate for heat generation differences across the polishing interface.
2Temperature
If multiple independently controlled dispensers are added for radial temperature control, then temperature uniformity improves, but the device complexity and number of components increase
Solution Approach 1:
The multiple dispensers are integrated into a single polishing apparatus system that performs both polishing and temperature control functions. The dispensers use a common fluid delivery infrastructure and can be controlled by a centralized system, allowing the same components to serve multiple purposes and reducing overall system complexity despite the increased number of temperature control elements.
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 solution enables precise temperature control of the polishing pad, reducing temperature variation and improving polishing performance by enhancing within-wafer uniformity and wafer-to-wafer consistency.
Implementation Method 1
a temperature control system including a source of heated fluid and a plurality of openings positioned over the platen and separated from the polishing pad and configured for the heated fluid to flow onto the polishing pad
Implementation Method 2
a source of coolant fluid and a plurality of openings positioned over the platen and separated from the polishing pad and configured for the coolant fluid to flow onto the polishing pad
Data Source
AI summary
A chemical mechanical polishing apparatus includes a platen to hold a polishing pad, a carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process, and a temperature control system including a source of a fluid medium and one or more openings positioned over the platen and separated from the polishing pad and configured for the fluid medium to flow onto the polishing pad to heat or cool the polishing pad.