Lead Support for IC Package Inner Lead Protection
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Solution Overview
Problem
Conventional semiconductor packages face challenges in miniaturization, reliability, and manufacturing costs due to issues like mold flash covering inner lead contacts, bent or lifted lead fingers, and reduced pin count, which hinder efficient connection to printed circuit boards.
Innovation Solution
The integrated circuit package system includes a paddle with dual rows of leads, an outer lead, and an inner lead, where a lead support is placed over the inner lead without covering its bottom side, providing structural reinforcement and ensuring the inner lead is exposed during encapsulation to prevent mold flashing and maintain electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the package is miniaturized to increase packaging density, then the size and thickness of the package are reduced, but the inner lead contacts become more susceptible to mold flash coverage and deformation
Solution Approach 1:
The lead support structure is placed over the inner leads before the molding process to prevent mold flash from covering the lead contacts. This preliminary protective action ensures that even as packages are miniaturized, the inner leads remain accessible and functional after encapsulation.
Solution Approach 2:
The lead support acts as an intermediary element between the inner leads and the molding compound. It prevents direct contact between the mold flash and the lead contacts, thereby protecting the electrical connectivity while allowing the package to be miniaturized.
2Stability of the object's composition
If the clamping pressure is increased to prevent lead finger lifting, then the lead position is stabilized, but the inner lead contacts may still be covered by mold flash due to debris accumulation
Solution Approach 1:
The lead support structure is extracted as a separate component that is placed over the inner leads before molding. This extraction allows the support to prevent mold flash coverage without interfering with the clamping pressure application to stabilize lead finger positions.
Solution Approach 2:
The lead support is positioned in advance to prevent mold flash from covering the lead contacts. This preliminary protective measure ensures that even when debris accumulates under the leads, the critical contact areas remain exposed and functional.
3Adaptability or versatility
If the number of I/O contacts is increased to improve functionality, then the pin count increases, but the manufacturing complexity and susceptibility to mold flash coverage increase
Solution Approach 1:
The lead support structure serves multiple functions: it protects inner leads from mold flash coverage, provides structural reinforcement for high-density lead arrangements, and ensures proper alignment during the molding process. This multi-functionality allows increased I/O counts without proportionally increasing manufacturing complexity.
Solution Approach 2:
The lead support is segmented to accommodate multiple rows of leads with increased pin counts. By dividing the support structure into sections that correspond to different lead regions, the design can scale to higher I/O densities while maintaining manageable manufacturing complexity.
4Quantity of substance
If the lead frame is etched to create inner leads, then the pin count increases, but the clamping pressure on one end may cause the other end to lift and become covered by mold flash
Solution Approach 1:
The lead support acts as an intermediary that bridges the paddle and the inner leads. It distributes the clamping pressure evenly along the lead length, preventing the lifting effect that occurs with conventional etched leads, and ensures continuous contact throughout the molding process.
Solution Approach 2:
The lead support is positioned over the etched inner leads before molding to prevent them from lifting or deforming under clamping pressure. This preliminary support ensures that the increased pin count from etching does not compromise the reliability of individual lead contacts.
Data Source
AI summary
An integrated circuit package system is provided including forming a paddle having an integrated circuit die thereover, an outer lead, and an inner lead between the paddle and the outer lead. The integrated circuit package system is also provided including placing a lead support over the inner lead without traversing to an inner body bottom side of the inner lead, connecting the integrated circuit die and the inner lead, and encapsulating the inner lead having the lead support thereover and the inner lead exposed.