Heat Spreader on Silicon Substrate for Thermal Management
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Solution Overview
Problem
Current heat spreader addition processes in electronic packages are complex and result in inadequate thermal performance due to the thickness of the heat spreader, leading to high stress and inefficient heat dissipation in high integration density devices.
Innovation Solution
The heat spreader is integrated directly onto the package substrate before the bumping process, utilizing a scraggy surface and conductive materials like Ni or Cu, and is in contact with the substrate to enhance adhesion and thermal conductivity, simplifying the process and improving thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the heat spreader is added after assembly process on the backside of the chip, then the heat spreader can be attached to the die, but the process becomes complicated and thermal performance is not improved sufficiently
Solution Approach 1:
The heat spreader is integrated onto the substrate before the bumping process and die attachment, rather than after assembly. This preliminary integration simplifies the manufacturing process and enables better thermal contact between the heat spreader and the die, improving thermal performance.
Solution Approach 2:
The heat spreader integration is merged with the substrate preparation process. The scraggy surface is created on the substrate, followed by heat spreader deposition in the same manufacturing sequence, combining multiple functions into a unified process flow that reduces complexity.
2Reliability
If the heat spreader is made thick to improve thermal performance, then heat dissipation is enhanced, but stress in the package increases
Solution Approach 1:
The heat spreader is implemented as a thin film deposited directly onto the substrate with a scraggy surface, rather than a thick rigid structure. This thin film approach provides sufficient thermal conduction while minimizing mechanical stress and deformation in the package.
Solution Approach 2:
The heat spreader thickness is optimized to a thin dimension that balances thermal performance with mechanical stress reduction. The scraggy surface geometry is also parameterized to maximize thermal contact while maintaining low stress states in the overall package structure.
3Reliability
If the heat spreader is integrated before bumping process with scraggy surface, then adhesion and thermal conductivity are enhanced, but the manufacturing process requires additional steps
Solution Approach 1:
A scraggy surface is created only in the specific region where the heat spreader will be deposited, providing enhanced adhesion and thermal conductivity locally at the heat spreader-substrate interface without affecting other areas of the substrate. This localized treatment adds minimal process complexity while delivering significant performance benefits.
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
This approach reduces overall package stress and enhances thermal performance by allowing for more efficient heat dissipation in high I/O count, high-performance electronic devices.
Implementation Method 1
The heat spreader is in contact with the substrate to enhance adhesion and thermal conductivity
Implementation Method 2
The heat spreader is integrated directly onto the package substrate before the bumping process, utilizing a scraggy surface and conductive materials like Ni or Cu, and is in contact with the substrate to enhance adhesion
Data Source
AI summary
Apparatus and methods for forming a heat spreader on a substrate to release heat for a semi-conductor package are disclosed. The apparatus comprises a substrate. A dielectric layer is formed next to the substrate and in contact with a surface of the substrate. A heat spreader is formed next to the substrate and in contact with another surface of the substrate. A passivation layer is formed next to the dielectric layer. A connection pad is placed on top of the passivation layer. The substrate may comprise additional through-silicon-vias. The contact surface between the substrate and the heat spreader may be a scraggy surface. The packaging method further proceeds to connect a chip to the connection pad by way of a connection device such as a solder ball or a bump.