Flip-Chip Carrier Substrate Reinforcement Structure Warpage Control
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Solution Overview
Problem
Existing IC packaging processes, particularly flip chip bonding, face challenges due to thermal stress-induced warpage caused by temperature fluctuations, leading to mechanical and thermal performance issues.
Innovation Solution
A reinforcement structure is embedded within the carrier substrate's periphery region, comprising metal posts that extend from the surface to minimize warpage by providing mechanical reinforcement and matching thermal expansion coefficients, thereby reducing stress and delamination during high-temperature processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flip chip bonding process is used to achieve functional density increase, then IC packaging capability is improved, but thermal stress-induced warpage increases
Solution Approach 1:
The patent applies local quality by embedding reinforcement structures (such as metal posts or rigid material regions) at specific peripheral locations of the carrier substrate where thermal stress concentrates. This localized reinforcement provides targeted support to counteract warpage without requiring overall substrate thickening or material change, thus maintaining the flip chip bonding capability while addressing the warpage issue at critical stress points.
Solution Approach 2:
The patent employs composite materials by combining the carrier substrate with reinforcement structures made of different materials (e.g., metal posts embedded in organic substrate, or rigid material regions with different thermal expansion coefficients). This composite structure creates a multi-material system that balances thermal expansion differences between the IC chip and carrier substrate, reducing thermal stress-induced warpage while preserving the functional density benefits of flip chip bonding.
2Ease of manufacture
If temperature fluctuations are experienced during bonding, then bonding process completion is achieved, but thermal stress and warpage increase
Solution Approach 1:
The patent applies beforehand cushioning by pre-embedding reinforcement structures (metal posts, rigid material regions) into the carrier substrate before the flip chip bonding process. These structures act as preventive measures that cushion against the thermal stress that will occur during temperature fluctuations in the bonding process, allowing the process to complete successfully while minimizing warpage and stress damage.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical properties of the carrier substrate through the addition of reinforcement structures with specific thermal and mechanical parameters. The reinforcement structures have tailored thermal expansion coefficients and moduli that compensate for the thermal stress generated during temperature fluctuations, enabling bonding process completion while controlling thermal stress levels.
3Stability of the object's composition
If carrier substrate is made larger to reduce stress, then warpage resistance is improved, but device size increases
Solution Approach 1:
The patent applies segmentation by dividing the reinforcement function into discrete, localized elements (individual metal posts or rigid material regions) distributed at strategic peripheral locations on the carrier substrate. This segmented approach provides effective warpage resistance through distributed support points without requiring a uniform increase in the overall carrier substrate area, maintaining compact device size while improving warpage resistance.
Solution Approach 2:
The patent employs another dimension by adding vertical reinforcement elements (metal posts extending through the substrate thickness, or rigid material regions with depth) rather than relying solely on horizontal substrate area expansion. This dimensional transition from 2D area increase to 3D structural reinforcement provides efficient warpage resistance with minimal footprint, avoiding device size increase while enhancing warpage resistance.
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 reinforcement structure effectively reduces warpage by up to 20%, decreases UBM and pre-solder maximum principal stress by 7% and 5% respectively, enhancing the mechanical and thermal performance of flip-chip packages.
Implementation Method 1
matching thermal expansion coefficients, thereby reducing stress and delamination during high-temperature processes
Data Source
AI summary
The present disclosure provides a carrier substrate, a device including the carrier substrate, and a method of bonding the carrier substrate to a chip. An exemplary device includes a carrier substrate having a chip region and a periphery region, and a chip bonded to the chip region of the carrier substrate. The carrier substrate includes a reinforcement structure embedded within the periphery region.