Layered Temporary Adhesive for Wafer Polishing Stress
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Solution Overview
Problem
Existing temporary adhesives for semiconductor wafers fail to provide adequate resistance to polishing stress while ensuring easy detachment, leading to potential wafer breakage or deformation during the three-dimensional stacking process.
Innovation Solution
A layered body comprising a temporary adhesive layer with a hydrosilylation-cured polyorganosiloxane adhesive layer and a polyorganosiloxane separation layer, featuring specific siloxane units and structures for enhanced spin coating, heat resistance, and easy peeling and removal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the temporary bonding is made easily detachable to prevent wafer breakage, then the bonding force is reduced, but the temporary bonding may be detached or shifted by polishing stress during polishing
Solution Approach 1:
The temporary adhesive layer is divided into two distinct functional layers: an adhesive layer for providing bonding force during polishing, and a separation layer for enabling easy detachment after polishing. This segmentation allows each layer to be optimized for its specific function without compromise
Solution Approach 2:
Different regions of the temporary adhesive layer have different properties: the adhesive layer has high bonding strength to resist polishing stress, while the separation layer has low bonding strength for easy detachment. Each layer is positioned at the appropriate location to fulfill its specific functional requirement
2Reliability
If a large force is applied for detachment to ensure resistance to polishing stress, then the bonding stability is improved, but the thinned semiconductor wafer may be broken or deformed
Solution Approach 1:
The temporary adhesive layer is segmented into an adhesive layer that provides polishing resistance and a separation layer that enables gentle detachment. This prevents the need to apply large forces that could break or deform the thinned wafer
Solution Approach 2:
The separation layer acts as an intermediary between the adhesive layer and the wafer surface, providing a controlled interface that allows easy detachment without transmitting large detaching forces to the fragile thinned wafer
3Ease of manufacture
If the separation layer is formed by plasma polymerization to enable easy removal, then the removal ease is improved, but the spin coating property and heat resistance may be compromised
Solution Approach 1:
The separation layer uses a polysiloxane composition with specific chemical parameters (siloxane units with aralkyl, epoxy, or phenyl groups) that change the material properties to achieve both good spin coating characteristics and adequate heat resistance while maintaining solvent removability
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 provides excellent resistance to polishing stress, enables easy detachment of the wafer from the support, and facilitates efficient removal of the separation layer using solvents, thereby preventing wafer damage and ensuring successful three-dimensional wafer stacking.
Implementation Method 1
an adhesive layer (A) that includes a polyorganosiloxane to be cured by a hydrosilylation reaction
Implementation Method 2
can be easily removed by a solvent from the wafer to which the separation layer is attached after peeling
Data Source
AI summary
A temporary adhesive is good peelability, heat resistance and cleaning removability after polishing of the rear surface of the wafer. A layered body for processing a rear surface of a wafer opposite to a circuit surface of the wafer, the layered body being a temporary adhesive loaded between a support and circuit surface of the wafer and including an adhesive layer (A) that includes a polyorganosiloxane to be cured by a hydrosilylation reaction and is releasably bonded, and a separation layer (B) includes a polyorganosiloxane and is releasably bonded, in which the polyorganosiloxane forming the separation layer (B) is a polyorganosiloxane containing a siloxane unit of RRSiO2/2 (provided that each R is bonded to a silicon atom as a Si—C bond), and at least one R is an aralkyl group, epoxy group, or phenyl group. Methods for producing and separating these layered bodies and composition for forming the separation layer.