Wafer Laminate Adhesive Layer for Thermal Delamination
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Solution Overview
Problem
Current methods for bonding and releasing semiconductor wafers during three-dimensional mounting are inadequate due to insufficient thermal stability, slow delamination processes, and risk of substrate contamination, particularly in high-temperature processes and actual production environments.
Innovation Solution
A wafer laminate is created using a support and an adhesive layer comprising a light-shielding resin layer and a non-silicone thermoplastic resin layer, with specific properties to ensure strong bonding, thermal resistance, and easy delamination, employing a resin composition with a condensed ring and crosslinking agents for enhanced durability and compatibility with TSV formation and wiring processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a heat-fusible hydrocarbon compound is used as an adhesive for temporary bonding, then the bonding and releasing process is simple and can be controlled by heating only, but the thermal stability is insufficient at high temperatures above 200°C
Solution Approach 1:
The adhesive layer is divided into two distinct layers: a lower layer containing a heat-fusible hydrocarbon compound for easy bonding and releasing, and an upper layer containing a high-temperature resistant adhesive for thermal stability during TSV formation and wiring processes. This segmentation allows each layer to perform its specialized function without interference.
Solution Approach 2:
The patent uses a composite adhesive layer structure combining two different adhesive materials with complementary properties. The lower layer uses a heat-fusible hydrocarbon compound (simple processing) while the upper layer uses a high-temperature resistant adhesive (thermal stability), creating a composite system that achieves both ease of manufacture and high temperature resistance.
2Reliability
If a silicone pressure-sensitive adhesive is used for the temporary adhesive layer, then the substrate can be bonded to the support, but the delamination process takes a very long time and is difficult to apply to actual production
Solution Approach 1:
The adhesive system is segmented into two functional layers: the lower layer uses a heat-fusible hydrocarbon compound that enables rapid thermal delamination for high productivity, while the upper layer uses a silicone pressure-sensitive adhesive that provides strong bonding durability. This segmentation resolves the contradiction between bonding reliability and delamination speed.
Solution Approach 2:
The patent changes the delamination mechanism from chemical dissolution (slow) to thermal melting (fast). The lower layer's heat-fusible hydrocarbon compound is designed to melt at specific temperatures, enabling rapid delamination without requiring chemical solvents or prolonged processing times, thus significantly improving productivity.
3Loss of time
If an adhesive containing a light-absorbing substance is irradiated with high-intensity light to decompose the adhesive layer, then the process time for separating substrate from support is shortened, but a metallic compound must be used which risks contamination of the substrate
Solution Approach 1:
The patent extracts the metal-containing light-absorbing substance from the adhesive composition and replaces it with organic compounds that have appropriate light absorption characteristics. This eliminates the contamination risk while maintaining the ability to perform photodecomposition for rapid delamination.
Solution Approach 2:
The patent uses organic compounds in the adhesive layer that can be cleanly decomposed or volatilized without leaving metallic residues. These organic materials serve as temporary, disposable bonding agents that can be completely removed without contaminating the substrate, unlike persistent metallic compounds.
4Strength
If the organic resin film protective tape is used during back side grinding, then the wafer is protected from breaking, but the tape is insufficient in strength and heat resistance for TSV formation and wiring layer formation
Solution Approach 1:
The protective function is segmented between the adhesive layer system and the protective tape. The adhesive layer (particularly the upper high-temperature resistant layer) provides the necessary thermal stability and mechanical strength for TSV formation and wiring processes, while the protective tape provides only the basic function of preventing wafer breakage during grinding. This segmentation allows each component to be optimized for its specific function.
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 a heat-resistant, durable bond that facilitates easy separation of wafers, enhances productivity, and supports the formation of uniform, stepped substrates, while maintaining compatibility with chemical vapor deposition and other critical semiconductor processes.
Implementation Method 1
an adhesive layer which includes a light-shielding resin layer (A) and a non-silicone thermoplastic resin-containing resin layer (B) in this order from the support side, the resin layer (A) includes a resin that contains a condensed ring in a main chain thereof
Data Source
AI summary
To provide a wafer laminate which permits easy bonding between a support and a wafer, permits easy delamination of a wafer from a support, enables enhanced productivity of a thin wafer, and is suited to production of a thin wafer, and for a method of producing the wafer laminate.The wafer laminate includes a support, an adhesive layer formed on the support, and a wafer laminated in such a manner that its front surface having a circuit surface faces the adhesive layer. The adhesive layer includes a light-shielding resin layer A and a non-silicone thermoplastic resin-coating resin layer B in this order from the support side. The resin layer A is composed of a resin that contains a repeating unit having a condensed ring, and the resin layer B has a storage elastic modulus E′ at 25° C. of 1 to 500 MPa and a tensile break strength of 5 to 50 MPa.