NCF Sidewall Epoxy Barrier for TCB Fillet Control
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Solution Overview
Problem
The thermal compression bonding (TCB) process in semiconductor device assembly causes non-conductive film (NCF) fillets to squeeze out of the packaging area, leading to defects, reliability issues, and increased wafer warpage.
Innovation Solution
Applying an epoxy layer on the sidewalls of stacked semiconductor dies as a barrier to prevent NCF material diffusion during the TCB process, while allowing NCF material to extend outside at corner regions without epoxy coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermal compression bonding process is applied to stack semiconductor dies, then bonding strength and electrical connection are improved, but NCF material diffuses outside packaging area causing defects and wafer warpage
Solution Approach 1:
The patent divides the sidewall surface into different functional zones by applying epoxy material selectively to specific regions. The sidewall is segmented into areas with epoxy coverage and areas without epoxy coverage, allowing different NCF material behaviors in different zones during TCB process.
Solution Approach 2:
The patent applies epoxy material to specific local regions of the sidewall rather than uniformly covering the entire sidewall. This creates local quality differences where certain areas have barrier properties (epoxy-covered) while other areas allow NCF material extension (non-epoxy covered), optimizing both fillet control and warpage prevention.
2Manufacturing precision
If epoxy layer is applied on sidewalls to prevent NCF diffusion, then NCF fillet control is improved, but device complexity increases due to additional processing steps
Solution Approach 1:
The epoxy material is applied to the sidewall surface before the thermal compression bonding process. This preliminary action prepares the sidewall with appropriate barrier properties in advance, controlling NCF material diffusion during the subsequent TCB process without requiring additional control mechanisms during bonding.
Solution Approach 2:
The epoxy material acts as an intermediary substance between the sidewall and the NCF material. It provides a controlled interface that regulates NCF material diffusion, allowing precise fillet control while simplifying the overall process by using a passive barrier material rather than active control mechanisms.
3Stability of the object's composition
If NCF material is allowed to extend at corner regions without epoxy coverage, then wafer warpage is reduced, but manufacturing precision may be compromised at center regions
Solution Approach 1:
The patent creates different local conditions at corner regions versus center regions of the sidewall. Corner regions are left without epoxy coverage to allow NCF material extension that prevents wafer warpage, while center regions have epoxy coverage to maintain precise NCF fillet control. This local differentiation resolves the contradiction between warpage control and manufacturing precision.
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 epoxy layer effectively prevents NCF fillet squeezing at center regions, reducing manufacturing defects and improving device reliability by maintaining proper NCF coverage and preventing wafer warpage.
Implementation Method 1
Applying an epoxy layer on the sidewalls of stacked semiconductor dies as a barrier to prevent NCF material diffusion during the TCB process
Implementation Method 2
The thermal compression bonding (TCB) process in semiconductor device assembly causes non-conductive film (NCF) fillets to squeeze out of the packaging area
Implementation Method 3
The thermal compression bonding (TCB) process in semiconductor device assembly causes non-conductive film (NCF) fillets to squeeze out of the packaging area
Data Source
AI summary
A semiconductor device is presented. The semiconductor device includes a lower semiconductor die, a stack of upper semiconductor dies disposed over the lower semiconductor die, a non-conductive film material disposed between adjacent semiconductor dies of the lower semiconductor die and the stack of upper semiconductor dies, and an epoxy material disposed on at least one sidewall of the stack of upper semiconductor dies, wherein the epoxy material has a different material composition to the NCF material.