Dam Structures Containing Solder Flow in Semiconductor Devices
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Solution Overview
Problem
The existing semiconductor element built-in devices face issues with electrical short-circuits due to the flowing-out of solder during the reflow heating process, caused by insufficient adhesion between the resin and the protection films, leading to defective products and reduced production yield.
Innovation Solution
The implementation of dams around the pads on both substrates to prevent solder from flowing out and improve adhesion between the resin and protection films, ensuring that the solder is contained within the resin layer and preventing electrical short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resin is used to seal the semiconductor element and solder terminals, then the solder can be contained during reflow heating, but the adhesion between the resin and protection films is insufficient causing solder to flow out onto neighboring pads
Solution Approach 1:
An undercoat layer is introduced as an intermediary between the protection film and the resin layer. This undercoat layer serves as a mediator that enhances adhesion between the resin and protection film, preventing solder from flowing out during reflow heating and causing electrical short-circuits.
Solution Approach 2:
The undercoat layer is applied in advance before the resin layer is formed. This preliminary action ensures that the adhesion interface is prepared beforehand, creating a reliable bonding surface that prevents solder leakage during subsequent reflow heating processes.
2Reliability
If plasma process is applied to roughen the protection film surfaces, then adhesion between resin and protection films is improved, but clearances are still generated at boundaries allowing solder to flow in
Solution Approach 1:
The undercoat layer acts as an intermediary that fills and seals the clearances formed at the boundaries between the protection film and resin layer. This mediator prevents solder from penetrating into these clearances during reflow heating, eliminating the electrical short-circuit problem.
Solution Approach 2:
The undercoat layer is selectively applied at the critical boundary regions between the protection film and resin layer. This local quality enhancement targets the specific areas where clearances form, providing improved adhesion and solder containment exactly where needed without affecting other regions.
3Ease of manufacture
If adhesion between resin and protection films is not ensured, then manufacturing is simpler, but solder flows out during reflow heating causing defective products
Solution Approach 1:
The undercoat layer is introduced as a simple intermediary step that significantly improves adhesion between the resin and protection film. This addition prevents solder leakage during reflow heating, eliminating defective products and improving production yield without substantially complicating the manufacturing process.
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 dams effectively block solder from flowing onto adjacent pads, enhancing the adhesion between the resin and protection films, thereby preventing electrical short-circuits and improving the production yield by ensuring reliable semiconductor element built-in devices.
Implementation Method 1
a resin layer provided between the first substrate and the second substrate such that the solder terminal and the semiconductor element are embedded in the resin layer
Implementation Method 2
a dam provided at least partially around at least one of the first and second pads so as to project away from at least one of the first and second protection films, the dam being configured to restrain the solder flowing from the solder terminal
Data Source
AI summary
A semiconductor element built-in device includes: a first substrate having a first pad thereon; a semiconductor element on the first substrate; a second substrate having a second pad thereon and mounted on the first substrate via a solder terminal having a solder coated thereon; a resin layer provided between the first substrate and the second substrate such that the solder terminal and the semiconductor element are embedded in the resin layer; and a dam provided at least partially around at least one of the first and second pads, the dam being configured to restrain the solder flowing from the solder terminal.