IC Package Mold Locks for Delamination Prevention
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Solution Overview
Problem
Integrated circuit packages face challenges with poor heat dissipation and warpage issues due to the use of molded plastic epoxy, leading to delamination and reliability problems, especially in demanding environmental conditions, and existing technologies have not effectively addressed these issues.
Innovation Solution
The integrated circuit package system features a paddle with a depression and external interconnects having recess segments, filled with a nonconductive material, which enhances adhesion and provides mold locks to improve reliability and reduce delamination, using a combination of structural features like holes and slots in the interconnects and tie bars to reinforce the encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If molded plastic epoxy is used for package protection, then package protection is improved, but heat dissipation deteriorates leading to device malfunctions
Solution Approach 1:
The patent uses a composite material system consisting of epoxy mold compound combined with metal interconnect structures (leads, tie-bars, paddles) to achieve both protection and heat dissipation. The metal components provide thermal pathways while the epoxy provides protective encapsulation, resolving the contradiction between protection and heat management.
2Reliability
If molded plastic epoxy is used for package protection, then package protection is improved, but delamination occurs due to poor heat dissipation and warpage
Solution Approach 1:
The patent incorporates mold locks and mechanical interlocking features (recesses in leads, tie-bars, and paddles) during the packaging process to pre-establish strong bonding interfaces. These preliminary structural actions prevent delamination before it can occur during subsequent thermal cycling or warpage events.
Solution Approach 2:
The combination of epoxy mold compound with metal interconnect structures creates a composite system where the metal components provide structural stability and thermal management, while the epoxy provides protection. This composite structure inherently resists delamination better than epoxy alone.
3Reliability
If lug feature is added to lead design for locking, then locking between lead and mold compound is improved, but metal-to-metal space is reduced and mold compound flow is disturbed
Solution Approach 1:
The patent transitions from two-dimensional lug features on lead surfaces to three-dimensional mold locks that extend vertically through the lead, tie-bar, and paddle structures. This dimensional change allows locking functionality without occupying additional horizontal metal-to-metal space, maintaining compact package geometry.
Solution Approach 2:
The mold lock structures are nested within the existing lead, tie-bar, and paddle geometries rather than adding external protrusions. The recesses and locking features are integrated into the metal structures themselves, eliminating the need for additional space and avoiding disturbance to mold compound flow.
4Adaptability or versatility
If die area is increased to cover more space, then device functionality is improved, but delamination problem becomes more serious due to reduced metal-to-metal space
Solution Approach 1:
The patent pre-establishes multiple mold lock anchor points in the leads, tie-bars, and paddles before die attachment. These preliminary structural features ensure that even with reduced metal-to-metal space, there are sufficient bonding interfaces distributed throughout the package to prevent delamination, regardless of die area size.
Data Source
AI summary
A method of manufacture of an integrated circuit package system includes forming a paddle having a paddle top surface, the paddle top surface having a depression provided therein, forming an external interconnect having a lead tip and a lead body with the lead body having a first recess segment along a length-wise dimension of the lead body, connecting a device over the paddle top surface and the external interconnect, and filling a substantially electrically nonconductive material in the depression.