CMP Pad Lamination via Reactive Hot Melt Adhesive
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Solution Overview
Problem
Conventional multilayer chemical mechanical polishing pads laminated with pressure sensitive adhesives tend to delaminate during use, leading to internal breakdown and rendering them useless in semiconductor wafer processing.
Innovation Solution
A chemical mechanical polishing pad manufacturing assembly that includes a subpad layer with wrap-around tabs, a backing plate, and a sacrificial layer, where an unset reactive hot melt adhesive is applied in a pattern and pressure sensitive adhesives are used to secure the tabs and sacrificial layer to the backing plate, forming a robust bond between the subpad and polishing layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure sensitive adhesive is used to laminate the subpad layer and polishing layer, then the manufacturing process is simple and fast, but the bonding strength is insufficient leading to delamination during use
Solution Approach 1:
The bonding process is segmented into two distinct stages: first, pressure sensitive adhesive is applied to the subpad layer and initial positioning is performed; second, reactive hot melt adhesive is applied to critical bonding zones (polishing layer to subpad layer interface) to create permanent bonds. This segmentation allows the process to benefit from both the speed of pressure sensitive adhesive application and the strength of reactive bonding.
Solution Approach 2:
The patent introduces reactive hot melt adhesive as an intermediary substance between the pressure sensitive adhesive and the polishing layer. This intermediary provides enhanced bonding strength at critical interfaces while allowing the pressure sensitive adhesive to handle initial positioning and less critical areas, thus resolving the contradiction between ease of manufacture and bond reliability.
2Reliability
If reactive hot melt adhesive is used to bond the polishing layer to the subpad layer, then delamination is prevented, but the manufacturing complexity and processing time increase
Solution Approach 1:
Instead of applying reactive hot melt adhesive uniformly across the entire bonding surface, the patent applies it locally to specific critical zones where delamination is most likely to occur (the interface between polishing layer and subpad layer). This local application maintains high bond strength where needed while minimizing the overall complexity and processing time of the manufacturing process.
Solution Approach 2:
The pressure sensitive adhesive is applied first to perform preliminary positioning and bonding of layers. This preliminary action establishes basic alignment and holds layers in place, allowing subsequent reactive hot melt adhesive application to focus only on enhancing critical bond zones rather than performing all bonding functions, thus reducing overall process complexity.
3Manufacturing precision
If wrap around tabs are used to secure the subpad layer to the backing plate, then positioning accuracy is improved, but the manufacturing steps increase due to tab removal
Solution Approach 1:
The wrap around tabs are designed as temporary extraction elements that are easily removed after serving their positioning function. The tabs extend beyond the backing plate edges, providing precise positioning during lamination, then are simply pulled out or cut away, leaving clean edges on the polishing pad. This extraction approach adds minimal complexity while significantly improving positioning accuracy.
Solution Approach 2:
The wrap around tabs are designed as disposable positioning aids that are inexpensive and easily removed. Their temporary nature allows them to be used for precise positioning during manufacturing without requiring complex permanent attachment mechanisms, thus improving positioning accuracy while adding minimal complexity to the overall process.
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 enhances the resilience and prevents delamination of the polishing pad, ensuring a stable and effective polishing process by forming a strong bond between the subpad and polishing layers, thus improving the reliability of the multilayer chemical mechanical polishing pads.
Implementation Method 1
an unset reactive hot melt adhesive is applied to the top surface of the subpad layer... allowing the unset reactive hot melt adhesive to set forming a reactive hot melt adhesive bond between the subpad layer and the polishing layer
Implementation Method 2
a first pressure sensitive adhesive applied to the bottom surface of the subpad layer... a second pressure sensitive adhesive interposed between the sacrificial layer and the bottom side of the backing plate
Data Source
AI summary
A method of manufacturing a chemical mechanical polishing pad is provided, comprising: providing a polishing layer; providing a chemical mechanical polishing pad manufacturing assembly, comprising: a subpad layer having a top surface, a bottom surface and at least two wrap around tabs; a backing plate having a top side and a bottom side; a sacrificial layer having at least two recessed areas designed to facilitate attachment of the subpad layer to the backing plate; an unset reactive hot melt adhesive applied to the top surface of the subpad layer, wherein the unset reactive hot melt adhesive is applied in a pattern of parallel lines; wherein the subpad layer is disposed on the top side of the backing plate and the sacrificial layer is disposed on the bottom side of the backing plate, and wherein the at least two wrap around tabs extend to the bottom side of the backing plate; stacking the polishing layer and the chemical mechanical polishing pad manufacturing assembly with the unset reactive hot melt adhesive interposed between the polishing layer and the subpad layer forming a stack; applying an axial force to the stack; allowing the unset reactive hot melt adhesive to set forming a reactive hot melt adhesive bond between the subpad layer and the polishing layer; separating the at least two wrap around tabs from the subpad layer; and, removing the subpad layer with the polishing layer bonded thereto from the backing plate.