Phenyl-Polysiloxane Temporary Adhesive for Wafer Backside Polishing
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Solution Overview
Problem
Existing temporary adhesives for semiconductor wafers fail to provide adequate stress resistance during polishing while ensuring easy detachment and effective removal after processing, leading to potential wafer breakage or deformation.
Innovation Solution
A temporary adhesive comprising a hydrosilylation-reacted component (A) with phenyl group-containing polyorganosiloxane (B) in specific ratios, allowing for excellent spin coating, heat resistance, and easy separation of the wafer from the support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a temporary adhesive is used to attach the wafer to the support for polishing, then the wafer can be securely fixed during the polishing process, but the adhesive may cause difficulty in separating the wafer from the support after polishing
Solution Approach 1:
The adhesive layer is segmented into multiple functional layers: a first adhesive layer containing silane-modified polyethylene composition that provides strong bonding to the wafer, and a second adhesive layer containing fluorinated polymer composition that provides release functionality. This segmentation allows each layer to perform its specific function optimally without interfering with the other.
Solution Approach 2:
The silane-modified polyethylene composition acts as an intermediary between the wafer and the fluorinated polymer release layer. It provides the primary adhesion to the wafer surface while allowing the fluorinated layer to mediate the release process by reducing surface energy and enabling controlled detachment.
2Reliability
If a strong adhesive is used to prevent wafer detachment during polishing, then polishing stress resistance is improved, but the risk of wafer breakage or deformation during detachment increases
Solution Approach 1:
The adhesive system is divided into two distinct layers with different functions: the first layer provides strong bonding to withstand polishing stresses, while the second layer provides a controlled release mechanism that minimizes stress during detachment, thereby preventing wafer breakage or deformation.
Solution Approach 2:
The adhesive composition changes the surface energy parameters through the fluorinated polymer layer, which has low surface energy that facilitates easy release. This parameter change allows the adhesive to transition from a high-bonding state during polishing to a low-bonding state during detachment, preventing wafer damage.
3Ease of manufacture
If conventional adhesive compositions are used, then the adhesive can be applied and cured, but the adhesive may not provide sufficient heat resistance during wafer thinning and TSV formation
Solution Approach 1:
The adhesive uses a composite material system combining silane-modified polyethylene and fluorinated polymer. The silane-modified polyethylene provides structural integrity and heat resistance, while the fluorinated polymer provides release functionality. This composite structure maintains adhesive performance at high temperatures during wafer thinning and TSV formation.
Solution Approach 2:
The adhesive composition modifies the thermal parameters of the adhesive system through the fluorinated polymer content (5-50 wt%), which adjusts the glass transition temperature and thermal stability of the adhesive layer, providing sufficient heat resistance during subsequent high-temperature processing steps.
4Device complexity
If the adhesive layer is made thin to reduce processing complexity, then spin coating properties improve, but the adhesive may not provide sufficient bonding strength
Solution Approach 1:
The thin adhesive layer (1-10 μm) achieves sufficient bonding strength through the composite material system where silane-modified polyethylene provides strong adhesion to the wafer surface and the fluorinated polymer enhances the bonding interface. The synergistic effect of these materials allows thin film formation with adequate mechanical strength.
Solution Approach 2:
The adhesive composition parameters are optimized to achieve high bonding strength in thin films: the silane modification provides crosslinking capability that enhances strength, while the fluorinated content (5-50 wt%) is controlled to balance adhesion and release properties, enabling thin film formation with sufficient bonding strength.
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 adhesive ensures robust attachment during polishing, easy separation post-processing, and maintains heat resistance during wafer thinning and TSV formation, facilitating three-dimensional integration.
Implementation Method 1
component (A) that is cured by a hydrosilylation reaction
Implementation Method 2
component (B) containing a phenyl group-containing polyorganosiloxane
Data Source
AI summary
There is provided a temporary adhesive that has excellent spin coating properties of a circuit side of a wafer and a support, and excellent heat resistance when the circuit side of the wafer or the support is attached to an adhesion layer or when a rear surface of the wafer is processed, and is capable of easily separating the circuit side of the wafer from the support after polishing the rear surface of the wafer, and simply removing the adhesive attached to the wafer or the support after the separation; a layered body using the temporary adhesive; and a processing method using the layered body. An adhesive for separatably attaching a support to a circuit side of a wafer to process a rear surface of the wafer, the adhesive comprising a component (A) that is cured by a hydrosilylation reaction and a component (B) containing a phenyl group-containing polyorganosiloxane, wherein a ratio in % by mass of the component (A) to the component (B) is 95:5 to 30:70. A separation method comprising applying the adhesive onto a first body to form an adhesion layer, attaching a second body to the adhesion layer, heating the adhesion layer from a side of the first body to cure the adhesive to form a layered body, processing the layered body, and carrying out separation between the adhesion layer, and the first body and the second body. The processing may be polishing the rear surface of the wafer.