Thermally Insulated Substrate Layout for TCB Corner Bumps
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Solution Overview
Problem
Legacy thermal compression bonding (TCB) processes in mobile electronic devices face challenges with corner bump attachments due to excessive heat loss through thermally conductive features in the substrate, resulting in poorer joint quality and reduced throughput.
Innovation Solution
The implementation of thermal insulation in corner regions of the substrate by removing thermally conductive elements such as copper traces or vias, creating cavities with lower thermal conductivity materials to maintain higher temperatures and improve bonding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermally conductive features (copper traces, vias) are present in the substrate, then thermal compression bonding can be performed, but excessive heat loss occurs at corner bumps resulting in poorer joint quality
Solution Approach 1:
The patent removes thermally conductive features (copper traces, vias) from corner regions of the substrate to eliminate the heat loss pathway. This extraction of problematic thermal conduction elements directly addresses the heat loss issue at corner bumps while preserving the bonding process capability.
Solution Approach 2:
The substrate is designed with non-uniform thermal conductivity by creating corner regions with removed conductive features while maintaining intact conductive features in central regions. This local modification allows different parts of the substrate to have different thermal properties, insulating corner bumps while enabling effective heat transfer for central bonding areas.
2Reliability
If thermally conductive features are removed from corner regions, then heat loss is reduced and joint quality improves, but substrate complexity increases
Solution Approach 1:
The substrate is segmented into distinct functional regions: corner regions with removed conductive features for thermal insulation, and central regions with intact conductive features for effective bonding. This segmentation allows the substrate to simultaneously provide both thermal insulation where needed and thermal conduction where beneficial.
Solution Approach 2:
Rather than uniformly modifying the entire substrate, the patent applies local quality changes only to corner regions. The selective removal of conductive features from specific locations creates the necessary thermal insulation without requiring complex modifications across the entire substrate structure.
3Reliability
If higher temperatures are maintained at corner bumps, then bonding quality improves, but the bonding process time must be extended
Solution Approach 1:
By removing thermally conductive features from corner regions, the patent eliminates the heat loss pathway that previously caused corner bumps to cool down during bonding. This extraction allows corner bumps to maintain bonding temperatures without requiring extended process time, as the thermal insulation is built into the substrate structure itself.
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 enhances the quality of first-level interconnect corner bumps by maintaining higher temperatures during the TCB process, leading to improved joint quality and increased throughput without compromising machine operation rates.
Implementation Method 1
a second region separate and distinct from the first region that has a lower thermal conductivity than the first region; and wherein the second region is to thermally insulate the first region when the die is coupled to the first region
Implementation Method 2
package assemblies using thermal compression bonding (TCB)
Data Source
AI summary
Embodiments herein relate to systems, apparatuses, or processes directed to a substrate that includes a first region to be coupled with a die, and a second region separate and distinct from the first region that has a lower thermal conductivity than the first region, where the second region is to thermally insulate the first region when the die is coupled to the first region. The thermal insulation of the second region may be used during a TCB process to increase the quality of each of the interconnects of the die by promoting a higher temperature at the connection points to facilitate full melting of solder.