Multi-Layer CMP Sub Pad for Uniform Wafer Planarization
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Solution Overview
Problem
The challenge in advanced manufacturing processes is achieving precise planarization of wafer surfaces during Chemical Mechanical Polishing (CMP) due to the need for improved precision and uniformity, particularly in photolithography processes, which current CMP apparatuses struggle to address effectively.
Innovation Solution
The introduction of multi-layer sub pads comprising an anti-deformation layer and a grooved main support layer, which provide enhanced rigidity and deformation resistance, along with adhesive films to maintain uniformity and stability during the polishing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-layer polishing pad is used, then the device complexity is low, but the manufacturing precision and uniformity of wafer surface planarization deteriorate
Solution Approach 1:
The polishing pad is divided into multiple functional layers: a top polishing layer for material removal, a middle anti-deformation layer to maintain pad flatness under pressure, and a bottom support layer for structural stability. This segmentation allows each layer to perform its specific function optimally, improving overall polishing precision without requiring excessive complexity in any single component.
Solution Approach 2:
The invention uses composite material construction with different layers made from materials having distinct properties - the polishing layer uses compliant material for good wafer contact, the anti-deformation layer uses rigid material to resist compression, and the support layer provides structural integrity. This composite approach enables the pad to simultaneously achieve soft contact for precision polishing and rigid support for maintaining uniformity.
2Manufacturing precision
If the polishing pad is made softer to improve contact with wafer surface, then the contact uniformity improves, but the pad deformation under pressure increases
Solution Approach 1:
The pad structure is segmented into a soft top layer for contact and a rigid bottom layer for support. The top polishing layer is made compliant to ensure uniform contact with the wafer surface, while the bottom support layer is made rigid to resist deformation under polishing pressure. This segmentation resolves the contradiction by assigning different mechanical properties to different functional zones.
Solution Approach 2:
Different regions of the polishing pad have different local qualities - the top surface is soft and compliant for good contact, while the bottom region is rigid and resistant to deformation. This local differentiation of material properties allows the pad to simultaneously achieve both uniform contact and resistance to deformation, resolving the contradiction between these two requirements.
3Stability of the object's composition
If the polishing pad is made rigid to resist deformation, then the structural stability improves, but the contact uniformity with wafer surface deteriorates
Solution Approach 1:
The polishing pad is segmented into distinct layers with the top polishing layer made compliant for good wafer contact and the bottom support layer made rigid for structural stability. This segmentation allows the rigid support layer to maintain structural integrity while the soft top layer ensures uniform contact, resolving the contradiction between these two requirements.
Solution Approach 2:
The invention employs composite material construction where the top layer uses compliant material for contact uniformity and the bottom layer uses rigid material for structural stability. This composite structure enables the pad to simultaneously achieve both soft contact characteristics and rigid support characteristics, resolving the contradiction between contact uniformity and structural stability.
Data Source
AI summary
An apparatus includes a top pad comprising a plurality of protrusions and a plurality of grooves between the plurality of protrusions, a first adhesive film underlying the top pad, and a first anti-deformation layer underlying and attached to the top pad through the first adhesive film. The first anti-deformation layer has a first hardness. The apparatus further includes a second adhesive film underlying the first anti-deformation layer, and a main support layer underlying and attached to the top pad through the second adhesive film. The main support layer has a second hardness lower than the first hardness.