TSOP Package Vertical Leads Reduce Parasitic Effects
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Solution Overview
Problem
The electronics industry faces challenges in packaging semiconductor devices in compact spaces, as the complexity of portable systems increases, requiring smaller components and reduced parasitic capacitance and inductance to enhance system performance and lower costs.
Innovation Solution
The use of a TSOP (thin shrink outline package) with eight or more I/O terminals, featuring shortened interconnects and a metal lead frame with pre-plating, die bonding adhesive, wire bonding with gold, silver, or copper alloys, and encapsulation in an epoxy-based molding compound, along with lead forming and singulation to achieve a reduced packaging footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional packaging is used, then device functionality is maintained, but package size and parasitic capacitance increase
Solution Approach 1:
The patent transitions from traditional lateral lead arrangements to vertical leads emerging from the bottom surface of the package. This dimensional change allows shorter interconnect paths between the device die and package terminals, reducing parasitic capacitance and inductance while enabling compact package footprint on the printed circuit board.
Solution Approach 2:
The patent modifies key geometric parameters including lead length (shortened to approximately 0.5mm from the package boundary), lead pitch (0.65mm), and package height (approximately 1.1mm). These parameter changes optimize the balance between mechanical strength, electrical performance, and space efficiency, achieving reduced parasitic effects while maintaining device functionality.
2Area of stationary object
If package size is reduced, then space on printed circuit board is saved, but manufacturing complexity increases
Solution Approach 1:
The patent integrates multiple functions into unified structures: the lead frame serves as both structural support and electrical interconnection, the molding compound provides both mechanical protection and environmental sealing, and the vertical leads combine mechanical attachment with electrical terminal functions. This merging reduces the number of discrete components and assembly steps despite the compact footprint.
Solution Approach 2:
The lead frame is pre-formed with integrated support structures and lead configurations before device assembly. The molding compound is prepared with precise dimensional specifications and material properties beforehand. These preliminary actions simplify the final assembly process and reduce manufacturing complexity despite the compact package design.
3Reliability
If interconnect length is shortened, then parasitic capacitance is reduced, but wire bond reliability may be affected
Solution Approach 1:
The patent employs composite material structures including gold-silver-copper alloy wire bonds that combine the advantages of each metal: gold provides oxidation resistance and conductivity, silver enhances conductivity, and copper reduces cost. This composite approach maintains wire bond strength and reliability while accommodating shorter interconnect lengths for reduced parasitic effects.
Solution Approach 2:
The patent optimizes wire bond parameters including diameter, length, and bonding force to match the shortened interconnect requirements. By adjusting these parameters, the wire bonds maintain sufficient mechanical strength and electrical reliability despite the reduced path length between device die and package terminals.
Data Source
AI summary
Consistent with an example embodiment, a thin outline shrink package (TSOP) provides for a significant reduction in lead pitch along with a reduced package profile for a semiconductor device die packaged, therein.