Die Pad Grooves Guide Resin Bleed-Out to Slots
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Solution Overview
Problem
Resin bleed-out during semiconductor package assembly leads to device failures, such as open circuit connections and bond wire adhesion problems, particularly in packages with large die sizes relative to die pads and down bonds, due to the separation and movement of die attach resin components from the leadframe surface.
Innovation Solution
Incorporating non-penetrating grooves between through-hole slots on the die pad to guide resin bleed-out material away from critical bonding areas, preventing saturation and flow towards the down bond region, thus creating a fluid connection that channels the resin bleed-out to collecting slots, thereby preventing it from reaching the down bond region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If die attach resin material is used to mount semiconductor die on die pad, then the die is securely attached and protected, but resin bleed-out occurs causing device failures and bond wire adhesion problems
Solution Approach 1:
The die pad surface is segmented into functional zones through grooves and slots. The grooves divide the die pad into regions, creating designated pathways for resin bleed-out while preserving critical bonding areas. This segmentation allows the resin to be channeled away from sensitive regions without compromising overall attachment reliability.
Solution Approach 2:
The harmful resin bleed-out is extracted from the bonding area by directing it into grooves and slots. The slots act as extraction points that remove excess resin from the critical die attachment zone, preventing it from interfering with bond wire adhesion and down bond connections.
2Reliability
If grooves are added to guide resin bleed-out, then resin flow is controlled and device reliability improves, but leadframe manufacturing complexity increases
Solution Approach 1:
Instead of modifying the entire die pad surface uniformly, grooves and slots are strategically placed only in specific locations where resin bleed-out needs to be managed. The grooves are positioned to channel resin away from critical areas while leaving other regions unchanged, maintaining simplicity where it is not needed.
Solution Approach 2:
The leadframe die pad incorporates a porous-like structure through grooves and slots that allow controlled resin flow. These features create a passive fluid management system that guides resin bleed-out through predefined pathways without requiring active control mechanisms or complex additional components.
3Ease of manufacture
If resin bleed-out is allowed to flow freely, then manufacturing process is simple, but resin reaches down bond region causing open circuit connections and adhesion failures
Solution Approach 1:
The grooves and slots serve as intermediary structures between the die attach resin source and the down bond region. These features act as mediators that intercept and redirect resin bleed-out, preventing direct contact between the resin and critical bonding areas while maintaining a relatively simple 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
This solution effectively reduces resin bleed-out issues, enhancing assembly reliability by preventing resin from reaching the down bond region, which can cause adhesion failures and connection problems, thereby improving yield and eliminating machine stops attributed to resin bleed-out.
Implementation Method 1
At least one non-penetrating groove (i.e., a partially etched groove) is in the die pad for providing a fluid connection including between the first and second slots for providing a flow channel for guiding the resin when received by the grooves after bleeding out from under the semiconductor die
Data Source
AI summary
A leadframe includes a die pad for mounting a semiconductor die with its top side facing up using a die attach resin material including a resin, the leadframe having leads or lead terminals beyond the die pad. The die pad includes slots including a first slot and at least a second slot on at least a first side of the die pad that penetrate a full thickness of the die pad. At least one non-penetrating groove is in the die pad for providing a fluid connection including between the first and second slots for providing a flow channel for guiding the resin when received by the grooves after bleeding out from under the semiconductor die to flow to at least one of the first slot and the second slot.