CMP Pressure Chamber Control for Region-Specific Polishing Endpoints
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) devices face issues with under-polishing and over-polishing due to differences in surface and underlying structures across different areas of a substrate, leading to inconsistent polishing endpoints.
Innovation Solution
A polishing method and device that utilizes multiple pressure chambers and sensors to monitor film thickness, allowing for independent control of polishing pressures in different regions of the substrate, determining and adjusting polishing endpoints individually for each region to prevent under-polishing and over-polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polishing pressure is uniformly applied across all substrate areas, then the polishing device structure is simple, but polishing endpoints vary across different regions causing under-polishing and over-polishing
Solution Approach 1:
The polishing head is divided into multiple pressure chambers (first pressure chamber and second pressure chamber) that can independently control polishing pressure in different substrate regions. This segmentation allows each region to be polished to its specific endpoint without affecting other regions, resolving the contradiction between precision and complexity.
Solution Approach 2:
Each pressure chamber is equipped with independent pressure control to provide locally optimized polishing pressure according to the specific requirements of each substrate region. This local quality approach ensures that regions with different surface structures receive appropriate pressure, achieving consistent polishing endpoints across all areas.
2Manufacturing precision
If polishing is stopped uniformly across all regions, then the control system is simple, but regions with different surface structures experience over-polishing or under-polishing
Solution Approach 1:
The substrate surface is divided into multiple regions (first region and second region) with different surface structures, and each region has its own pressure control system. This allows independent monitoring and control of polishing endpoints for each region, achieving precise film thickness control without requiring complex centralized automation.
Solution Approach 2:
Monitor signals are acquired from different substrate areas during polishing, and the operation control part uses this feedback to determine region-specific polishing endpoints. The system automatically adjusts pressure in each pressure chamber based on real-time monitoring, achieving precise control while maintaining reasonable automation levels.
3Manufacturing precision
If region-specific pressure control is implemented, then polishing precision is improved, but the number of pressure regulators and control components increases
Solution Approach 1:
The pressure control system is segmented into multiple independent pressure regulators (first pressure regulator and second pressure regulator), each managing a specific pressure chamber. This modular approach allows precise control in each region while keeping individual regulator complexity low, balancing precision requirements with device complexity.
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
Ensures precise control over polishing endpoints in various substrate regions, preventing under-polishing and over-polishing, thereby maintaining consistent film thickness across the substrate.
Implementation Method 1
a sensor outputting a film thickness monitoring signal in accordance to a film thickness of the substrate
Implementation Method 2
chemical mechanical polishing (CMP) uses a polishing device to supply polishing liquid containing abrasive grains such as silica (SiO2) onto the polishing surface of a polishing pad
Implementation Method 3
a substrate is pressed against a polishing surface of the polishing pad by a first pressure chamber and a second pressure chamber of a polishing head
Data Source
AI summary
A polishing method and a polishing device are provided. The polishing method includes: outputting a film thickness monitoring signal in accordance to a film thickness of a substrate by a sensor during polishing of the substrate; determining, based on the film thickness monitoring signal in each of a first region and a second region on the substrate, a first polishing endpoint in the first region and a second polishing endpoint in the second region, in which the second polishing endpoint is a polishing endpoint later than the first polishing endpoint; stopping progress of polishing in the first region by reducing pressure in a first pressure chamber in response to the first polishing endpoint being reached, and stopping progress of polishing in the second region by reducing pressure in a second pressure chamber in response to the second polishing endpoint being reached.