Dual Membrane Substrate Carrier Head for CMP Uniformity
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Solution Overview
Problem
Current substrate carrier designs for chemical mechanical planarization (CMP) face challenges in achieving uniform pressure application and material removal, leading to non-uniformities and increased risk of wafer breakage, which affects yield and manufacturing costs.
Innovation Solution
The substrate carrier head incorporates a dual membrane system with strategically placed cavities and holes for fluid communication, an adjustable spring force, and a bladder to move support plates, ensuring coplanarity and uniform pressure distribution, thereby reducing non-uniformities and enhancing substrate handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single membrane system is used in the substrate carrier, then the device complexity is reduced, but the pressure distribution uniformity and substrate surface flatness deteriorate
Solution Approach 1:
The single membrane system is segmented into a first resilient membrane and a second resilient membrane, each providing independent substrate support portions. This segmentation allows each membrane to be optimized for specific regions of the substrate, improving overall pressure distribution uniformity and surface flatness while managing complexity through modular design
Solution Approach 2:
The dual membrane system introduces a vertical dimension with multiple membrane layers (first membrane and second membrane stacked arrangement), creating multi-layer support structures that enhance pressure distribution control and substrate surface flatness beyond what a single membrane layer can achieve
2Productivity
If higher pressure is applied between the wafer and carrier during CMP processing, then the CMP efficiency is improved, but the risk of wafer breakage increases
Solution Approach 1:
The first and second substrate support portions provide differentiated local support characteristics across the substrate surface. The first membrane provides broader support while the second membrane provides targeted support in specific regions, allowing high pressure to be applied uniformly without creating localized stress concentration points that would cause wafer breakage
Solution Approach 2:
The resilient nature of both membranes provides inherent cushioning effect before wafer breakage can occur. The dual membrane structure absorbs and distributes stress, preventing sudden pressure spikes that could lead to wafer failure during high-pressure CMP processing
3Manufacturing precision
If a dual membrane system with multiple support portions is used, then the pressure distribution uniformity is improved, but the device complexity increases
Solution Approach 1:
The first and second substrate support portions are merged into a single integrated carrier head assembly with unified fluid communication systems. The hollow cavity provides common fluid distribution to both membranes, and the support plates are integrated into the same structural framework, reducing overall system complexity while maintaining dual membrane functionality
Solution Approach 2:
The hollow cavity serves multiple functions: it provides fluid communication to both the first and second membranes, acts as a structural support element, and enables coordinated actuation of both membranes. This multi-functionality reduces the need for separate systems for each membrane, managing complexity through versatile design
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 design improves flatness tolerances and reduces the likelihood of wafer breakage, resulting in increased yield and decreased manufacturing costs by ensuring uniform material removal and improved substrate surface quality.
Implementation Method 1
a first resilient membrane (25) and a second resilient membrane (30) stacked or positioned adjacent to each other, wherein the first resilient membrane (25) includes a first substrate support portion with a width W1, and the second resilient membrane (30) includes a second substrate support portion with a width W2
Implementation Method 2
at least one of the outer support plate and the inner support plate comprise a plurality of holes configured to extend through a thickness of the at least one of the outer support plate and the inner support plate, and to provide fluid communication between at least one of the first cavity and the first substrate support portion and the second cavity and the second substrate support portion
Data Source
Figure 1~2
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AI summary
A substrate carrier head is disclosed. In one aspect, the carrier head includes a carrier body, a substrate retainer, a first resilient membrane and a second resilient membrane. The carrier head can include an inner support plate. The substrate retainer is attached to the carrier body. The substrate retainer includes an aperture configured to receive a substrate. The first resilient membrane includes a first imperforated substrate support portion with a width W1. The second resilient membrane includes a second imperforated substrate support portion with a width W2. The second imperforated substrate support portion is positioned between the first substrate support portion and the carrier body, and is configured to selectively provide a force against at least an inner section of the first imperforated substrate support portion. The inner support plate is fixed relative to the carrier body and includes a support surface configured to support the second imperforated substrate support portion.