Heat-Spreading Lid Bonding for Dense Chip Package Cooling
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Solution Overview
Problem
The challenge of heat dissipation in advanced semiconductor packaging structures, particularly in 3D and 2.5D packaging, is exacerbated by the need for efficient heat management as devices become more integrated and compact, leading to manufacturing challenges.
Innovation Solution
A package structure incorporating a heat-spreading lid with a metallic structure that forms an alloy with a thermal conductive layer, enhancing adhesion and heat dissipation through the formation of an alloy structure that stabilizes the thermal conductive layer during bonding, using materials like indium and gold to create a strong joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat-spreading lid is added to improve heat dissipation, then heat dissipation performance is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into the lid structure: it serves as both a protective cover and a heat dissipation component. The lid is integrated with a thermal conductive layer and bonding structures, merging protection, heat transfer, and mechanical bonding functions into a single component, thereby improving heat dissipation without proportionally increasing complexity.
Solution Approach 2:
The lid is designed as a multi-functional element that simultaneously provides mechanical protection, thermal management, and structural bonding. By making the lid universal in its functions, the patent avoids adding separate components for each function, thus improving heat dissipation performance while minimizing the increase in device complexity.
2Temperature
If a thermal conductive layer is formed to improve heat transfer, then heat conduction is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs a reflow soldering process that utilizes temperature-parameter changes to achieve both bonding and thermal conductive layer formation in a single step. By controlling the thermal profile parameters (temperature, time, heating rate), the process achieves the required manufacturing precision without requiring separate high-precision steps for each function.
Solution Approach 2:
The manufacturing process utilizes phase transitions of the solder material (melting and solidification during reflow) to automatically form the thermal conductive layer with appropriate precision. The phase change process self-regulates the material flow and distribution, reducing the need for external precision control mechanisms.
3Productivity
If package size is reduced to improve density, then productivity is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The patent utilizes a thin-film thermal conductive layer integrated into the lid structure. This thin film provides efficient heat conduction pathways within the compact package, enabling effective heat dissipation despite the reduced overall package size and increased packaging density.
Solution Approach 2:
The lid assembly employs composite material structures combining different thermal conductivity materials in layers. This composite approach maximizes heat dissipation capability within the minimized package volume by strategically placing high-thermal-conductivity materials where heat flow is most critical, thereby maintaining heat dissipation performance while improving productivity through higher density.
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 solution improves heat dissipation and adhesion, ensuring efficient heat transfer from semiconductor chips to the lid, thereby enhancing the performance and reliability of the package structure.
Implementation Method 1
pressing the heat-spreading lid against the chip-containing structure at an elevated temperature such that a portion of or an entirety of the metallic structure and a portion of or an entirety of the thermal conductive layer are transformed into an intermetallic compound material
Data Source
AI summary
A package structure and a formation method are provided. The method includes disposing a chip-containing structure over a substrate and forming a thermal conductive layer over the chip-containing structure. The method also includes disposing a heat-spreading lid over the chip-containing structure and the thermal conductive layer. A metallic structure is embedded in the heat-spreading lid, and the metallic structure faces the thermal conductive layer. The method further includes pressing the heat-spreading lid against the chip-containing structure at an elevated temperature such that a portion of or an entirety of the metallic structure and a portion of or an entirety of the thermal conductive layer are transformed into an intermetallic compound material.