Funnel Shaped Lead Circuit Device for High Pin Count Reliability
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Solution Overview
Problem
Conventional semiconductor device manufacturing methods result in poor connection reliability due to reduced area of exposed signal-connecting terminals and insufficient connection strength between terminals and tie bars, especially as terminal sizes decrease with increasing pin count.
Innovation Solution
A circuit device with leads that spread from the inner side of the sealing resin toward the peripheral portion, exposing both lower and side surfaces, and a manufacturing method involving a lead frame with wider connection portions between leads and tie bars to enhance connection reliability and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of lead terminals is increased to accommodate higher capacitance and more signal lines, then the functionality and signal capacity of the semiconductor device is improved, but the mounting area required for the device increases
Solution Approach 1:
The lead structure transitions from a conventional planar configuration to a three-dimensional configuration by exposing both the lower surface and side surface of the lead. This dimensional change allows the lead to make contact with brazing filler material in multiple directions, effectively increasing the connection capacity without requiring additional mounting area on the circuit board.
2Area of stationary object
If the semiconductor device is downsized to reduce mounting area, then the device meets space constraints in portable applications, but the area of exposed signal-connecting terminals decreases leading to poor connection reliability
Solution Approach 1:
By exposing both the lower surface and side surface of the lead, the invention creates a multi-surface contact structure. This allows the lead to establish reliable electrical and mechanical connections with brazing filler material even when the overall device size is reduced, as the multi-dimensional exposure compensates for the reduced terminal area.
Solution Approach 2:
The lead structure is designed with differentiated local characteristics where specific portions (lower surface and side surface) are exposed to provide enhanced contact areas. This local quality optimization ensures that critical connection points maintain sufficient contact area even when the overall terminal size is reduced for device downsizing.
3Productivity
If the area of signal-connecting terminals is reduced to accommodate higher pin count, then more terminals can be packed into the same space, but the contact area with brazing filler material decreases resulting in poor connection reliability
Solution Approach 1:
The invention addresses the contact area limitation by extending the lead exposure in multiple dimensions - both the lower surface and side surface are exposed to provide additional contact interfaces. This multi-dimensional exposure compensates for the reduced terminal area, allowing high pin count density to be achieved while maintaining adequate brazing contact area for reliable connections.
Data Source
AI summary
Provided are: a circuit device demonstrating an improved connection reliability while being mounted; and a method for manufacturing the same. The circuit device of the present invention includes: an island; leads arranged around the island, each lead having a lower surface and a side surface exposed to the outside; and a semiconductor element mounted on the island and electrically connected to the leads through thin metal wires. Furthermore, the exposed end portion of the lead is formed to spread toward the outside. By forming the lead in this manner, the area where the lead comes into contact with a brazing filler material is increased, thus improving the connection strength therebetween.