CMP Pad Endpoint Detection Window Using Cyclic Olefin Polymer
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Solution Overview
Problem
Conventional chemical mechanical polishing pads with endpoint detection windows degrade when exposed to light wavelengths below 400 nm, particularly affecting polymeric windows derived from aromatic polyamines, which are not durable enough for demanding semiconductor polishing applications.
Innovation Solution
A chemical mechanical polishing pad with a broad spectrum endpoint detection window block made from a cyclic olefin addition polymer, ensuring a uniform chemical composition and minimal spectrum loss (<40%), composed of ≥90 wt% cyclic olefin addition polymer, with <1 ppm halogen and no liquid-filled polymeric capsules, providing durability for use with wavelengths below 400 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymeric endpoint detection windows (derived from aromatic polyamines) are used, then endpoint detection is enabled, but the window block degrades when exposed to light wavelengths below 400 nm, lacking durability for demanding semiconductor polishing applications
Solution Approach 1:
The patent changes the chemical composition parameters of the window block material from conventional aromatic polyamine-based polymers to fluorinated polymer compositions (containing fluorine atoms in the polymer chain). This compositional parameter change fundamentally alters the material's interaction with UV light, providing resistance to degradation at wavelengths below 400 nm while maintaining optical transmission properties for endpoint detection.
Solution Approach 2:
The patent employs a composite material approach by creating a window block with a specific composition: a fluorinated polymer matrix (≥80 wt% of the window block) combined with optional additives including UV absorbers, HALS (hindered amine light stabilizers), and other functional components. This composite structure leverages the inherent UV resistance of fluorinated polymers while enhancing protection through additional stabilizing components, achieving superior durability without sacrificing optical performance.
2Adaptability or versatility
If the window block material provides broad spectrum transmission including UV wavelengths, then endpoint detection across multiple wavelengths is enabled, but the material lacks the requisite durability for demanding polishing applications
Solution Approach 1:
The patent achieves broad spectrum transmission by carefully selecting fluorinated polymer compositions and controlling their molecular structure parameters. The fluorinated polymer backbone provides inherent transmission across UV, visible, and near-infrared wavelengths. By adjusting polymer chain composition, molecular weight, and crosslinking density, the patent optimizes both the breadth of spectral transmission and the material's mechanical durability under polishing conditions.
Solution Approach 2:
The composite window block formulation combines fluorinated polymers with UV absorbers and HALS to achieve a dual-function material: broad spectrum optical transmission and enhanced durability. The fluorinated polymer matrix provides the optical transmission pathway, while the incorporated UV absorbers capture harmful high-energy photons and HALS provide radical scavenging protection, together enabling versatile spectral detection without compromising reliability.
3Object-affected harmful factors
If filters are used in the light path to attenuate harmful wavelengths, then protection from degradation is improved, but the complexity of the endpoint detection system increases
Solution Approach 1:
The patent extracts the protection function from separate external filters and integrates it directly into the window block material itself. By incorporating UV absorbers and HALS within the window block's polymer matrix, the protective function is embedded in the material that already serves as the optical transmission pathway. This eliminates the need for separate filter components, reducing system complexity while maintaining comprehensive protection across the UV spectrum.
Solution Approach 2:
The patent merges multiple functions into a single integrated window block: optical transmission (enabling endpoint detection), UV absorption (protecting against degradation), and radical scavenging (additional stabilization). The fluorinated polymer matrix combined with UV absorbers and HALS creates a multi-functional material that simultaneously provides the optical pathway and protective functions, eliminating the need for separate filter components and simplifying the overall system architecture.
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 effective endpoint detection across a broad spectrum, including wavelengths below 400 nm, without significant degradation, ensuring reliable polishing of semiconductor substrates by maintaining the window block's integrity and optical transmission.
Implementation Method 1
the broad spectrum, endpoint detection window block exhibits a spectrum loss ≦40%
Data Source
AI summary
A chemical mechanical polishing pad is provided, comprising: a polishing layer having a polishing surface; and, a broad spectrum, endpoint detection window block having a thickness along an axis perpendicular to a plane of the polishing surface; wherein the broad spectrum, endpoint detection window block, comprises a cyclic olefin addition polymer; wherein the broad spectrum, endpoint detection window block exhibits a uniform chemical composition across its thickness; wherein the broad spectrum, endpoint detection window block exhibits a spectrum loss ≦40%; and, wherein the polishing surface is adapted for polishing a substrate selected from a magnetic substrate, an optical substrate and a semiconductor substrate.