Stacked Semiconductor Device Adhesive Film Patterning
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Solution Overview
Problem
Conventional semiconductor device stacking methods face reliability issues due to insufficient adhesion between stacked chips, primarily caused by adhesive films with high solvent and photoactive compound density but low reactant density, leading to uneven mounting surfaces and decreased contact areas for adhesion.
Innovation Solution
A multi-layer adhesive film structure is employed, comprising a first patternable adhesive film with better patterning properties and a second puncturable adhesive film with superior puncturing properties, allowing for improved electrical connections and enhanced adhesion through thermal compression and patterning processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single adhesive film with high solvent and photoactive compound density is used for stacking semiconductor devices, then the adhesive film can be easily patterned, but the adhesion between stacked chips becomes insufficient due to low reactant density
Solution Approach 1:
The adhesive structure is divided into two separate adhesive films: a first adhesive film optimized for patterning (with high solvent and photoactive compound density) and a second adhesive film optimized for adhesion (with high reactant density). This segmentation allows each film to specialize in one function, resolving the contradiction between ease of patterning and adhesion reliability.
Solution Approach 2:
Different regions of the adhesive structure have different properties: the first adhesive film has properties suitable for patterning (higher solvent and photoactive compound density), while the second adhesive film has properties suitable for bonding (higher reactant density). This local differentiation of properties allows both patterning ease and adhesion reliability to be optimized in their respective locations.
2Reliability
If a single adhesive film with high reactant density is used for stacking semiconductor devices, then adhesion between stacked chips improves, but the adhesive film becomes difficult to pattern, leading to uneven mounting surfaces
Solution Approach 1:
The adhesive structure is divided into two separate adhesive films: a first adhesive film optimized for patterning (with high solvent and photoactive compound density) and a second adhesive film optimized for adhesion (with high reactant density). This segmentation allows each film to specialize in one function, resolving the contradiction between ease of patterning and adhesion reliability.
Solution Approach 2:
Different regions of the adhesive structure have different properties: the first adhesive film has properties suitable for patterning (higher solvent and photoactive compound density), while the second adhesive film has properties suitable for bonding (higher reactant density). This local differentiation of properties allows both patterning ease and adhesion reliability to be optimized in their respective locations.
3Reliability
If adhesive film material is optimized for puncturing properties, then electrical connections between stacked devices improve, but patterning properties deteriorate
Solution Approach 1:
The adhesive structure is divided into two separate adhesive films: a first adhesive film optimized for patterning (with high solvent and photoactive compound density) and a second adhesive film optimized for adhesion (with high reactant density). This segmentation allows each film to specialize in one function, resolving the contradiction between ease of patterning and adhesion reliability.
Solution Approach 2:
Different regions of the adhesive structure have different properties: the first adhesive film has properties suitable for patterning (higher solvent and photoactive compound density), while the second adhesive film has properties suitable for bonding (higher reactant density). This local differentiation of properties allows both patterning ease and adhesion reliability to be optimized in their respective locations.
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 multi-layer adhesive film structure enhances the reliability of the stacked semiconductor device structure by providing stronger adhesion and electrical connections, addressing the limitations of conventional methods by optimizing both patterning and puncturing properties.
Implementation Method 1
The adhesive film 30a may include a patternable material that may be selectively etched (e.g., photolithography process) to expose at least a part of the head of via-electrode 22a
Implementation Method 2
The semiconductor devices may be stacked so as to electrically connect the via-electrodes by puncturing the second adhesive film with the protruding lower parts (ends) of the via-electrodes. Stacking the semiconductor devices may be performed by thermal compression.
Data Source
AI summary
A stacked structure of semiconductor devices may include a plurality of stacked semiconductor devices, each having an upper surface and a lower surface and one or more via electrodes protruding from the upper surface to the lower surface. The via-electrodes may have upper parts (heads) protruding from the upper surface and lower parts (ends) protruding from the lower surface. The stacked semiconductor devices may be electrically connected to each other through the via-electrodes. A first adhesive film (e.g., patternable material) and a second adhesive film (e.g. puncturable material) may be formed between the stacked semiconductor devices. The stacked structure of semiconductor devices may be mounted on the upper surface of a printed circuit board (PCB) having a mount-specific adhesive film to form a semiconductor device package. The mounted stacked structure and the upper surface of the PCB may be further covered with a molding material.