Semiconductor Package Thermal Dissipation via Undulating Attachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor packages face challenges in heat transfer due to limited thermal conductivity of plastic molding materials, leading to potential damage from heat buildup and increased manufacturing costs with non-standard techniques and safety concerns.
Innovation Solution
A semiconductor package design with a conductive substrate and high thermal conductivity mold compound, where the major current carrying electrode is oriented upwards for improved heat transfer through the top surface, combined with an undulating or non-planar attachment structure and optional heat sink for enhanced thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plastic molding material is used to encapsulate the semiconductor device, then the device is protected from damage or contamination, but the thermal conductivity out of the package is limited
Solution Approach 1:
The patent changes the thermal parameter of the mold compound by specifying materials with thermal conductivity of at least 1.0 W/m·K, and preferably at least 2.0 W/m·K. This parameter change allows the mold compound to maintain its protective function while significantly improving heat transfer capability from the semiconductor device through the package.
Solution Approach 2:
The patent employs composite material solutions by combining the mold compound with a heat sink having thermal conductivity of at least 50 W/m·K. This composite structure allows the mold compound to provide protection while the high-conductivity heat sink materials (such as aluminum, copper, or ceramic composites) handle the thermal dissipation, resolving the contradiction between protection and heat transfer.
2Device complexity
If heat is transferred through the lower part of the package next to the printed circuit board, then the package structure is simple, but the printed circuit board cannot properly dissipate large amounts of heat causing warping and damage
Solution Approach 1:
The patent transitions the heat transfer path from a two-dimensional planar transfer through the PCB to a three-dimensional vertical transfer through the package. By attaching the heat sink to the top surface of the package and conducting heat upward through the mold compound and heat sink structure, the design adds a vertical dimension to heat dissipation, eliminating PCB warping while maintaining structural simplicity.
3Temperature
If plastic mold compound is eliminated altogether to improve heat transfer, then thermal conductivity is improved, but the semiconductor is left unprotected making it susceptible to damage or contamination
Solution Approach 1:
The patent changes the protective function of the mold compound from purely mechanical protection to a dual function of protection and thermal management. By specifying mold compounds with minimum thermal conductivity thresholds (1.0 W/m·K, preferably 2.0 W/m·K), the patent ensures that the protective encapsulation material also serves as an effective thermal pathway, eliminating the need to remove the compound while improving heat transfer.
4Temperature
If non-standard manufacturing techniques are used to attach heat sink, then heat transfer capability is improved, but manufacturing cycle time increases and manufacturing costs increase
Solution Approach 1:
The patent applies preliminary action by pre-attaching the heat sink to the semiconductor device before the molding process. This sequence allows the heat sink to be positioned and secured in advance, then the mold compound is applied to encapsulate both the device and heat sink together in a single operation, eliminating subsequent attachment steps and reducing manufacturing cycle time while maintaining effective thermal contact.
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
The design achieves improved thermal dissipation without compromising device reliability, safety, or manufacturing costs, with thermal resistance comparable to or better than existing DirectFET™ products, while maintaining a compact profile and ensuring component protection.
Implementation Method 1
the thermal conductivity out of a package is often limited by the plastic molding material
Implementation Method 2
Such packages may also include a heat sink attached to the top of the package to further aid in heat transfer
Data Source
AI summary
In one embodiment, a packaged semiconductor device having enhanced thermal dissipation characteristics includes a lead frame structure and a semiconductor chip having a major current carrying or heat generating electrode. The semiconductor chip is oriented so that the major current carrying electrode faces the top of the package or away from the next level of assembly. The packaged semiconductor device further includes a non-planar, stepped or undulating attachment structure coupling the current carrying electrode to the lead frame. A high thermal conductivity mold compound and thin package profile further enhance thermal dissipation.