Conductive Pillar Bonding via Segmented Support Substrate
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Solution Overview
Problem
The semiconductor industry faces challenges in forming bonding structures between packages due to coefficient of thermal expansion mismatch, leading to warpage and high bridging risk during reflow processes, and the use of through molding vias increases fabrication costs and time with limited pitch.
Innovation Solution
The use of conductive pillars bonded to contact pads via a solder reflow process reduces the pitch between bonding structures and minimizes sliding and shifting issues, with the pillars being secured using a support substrate and potentially a protective layer to prevent collapse during reflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If through molding vias are used to form bonding structures, then the fabrication process is simplified, but the pitch between bonding structures increases and warpage occurs due to coefficient of thermal expansion mismatch
Solution Approach 1:
The bonding structure is segmented into multiple components: a conductive pillar, a bonding pad, and a bonding structure formed separately. The conductive pillar is formed in a first substrate, the bonding structure is formed in a second substrate, and they are bonded together. This segmentation allows for smaller pitch between bonding structures while simplifying the fabrication process by avoiding through molding vias.
2Ease of manufacture
If through molding vias are used to form bonding structures, then the fabrication process is simplified, but warpage occurs due to coefficient of thermal expansion mismatch
Solution Approach 1:
The bonding structure is segmented into multiple components: a conductive pillar, a bonding pad, and a bonding structure formed separately. The conductive pillar is formed in a first substrate, the bonding structure is formed in a second substrate, and they are bonded together. This segmentation allows for smaller pitch between bonding structures while simplifying the fabrication process by avoiding through molding vias.
3Ease of manufacture
If traditional bonding structures are used, then the fabrication process is straightforward, but the pitch between bonding structures is large and bridging risk increases
Solution Approach 1:
The bonding structure is segmented into multiple components: a conductive pillar, a bonding pad, and a bonding structure formed separately. The conductive pillar is formed in a first substrate, the bonding structure is formed in a second substrate, and they are bonded together. This segmentation allows for smaller pitch between bonding structures while simplifying the fabrication process by avoiding through molding vias.
Solution Approach 2:
A support substrate is introduced as an intermediary to hold the conductive pillars during the bonding process. The support substrate prevents collapse of the conductive pillars and reduces bridging risk. After bonding, the support substrate is removed. This intermediary element enables smaller pitch while maintaining fabrication simplicity.
4Manufacturing precision
If conductive pillars with small pitch are formed, then the density of bonding structures increases, but the conductive pillars may collapse during reflow process
Solution Approach 1:
A support substrate is introduced as an intermediary to hold the conductive pillars during the bonding process. The support substrate prevents collapse of the conductive pillars and reduces bridging risk. After bonding, the support substrate is removed. This intermediary element enables smaller pitch while maintaining fabrication simplicity.
Solution Approach 2:
The support substrate provides beforehand cushioning and mechanical support to the conductive pillars before and during the reflow process. This prevents collapse of the conductive pillars when formed with small pitch, allowing higher density bonding structures without compromising their strength.
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 the pitch between bonding structures, decreases the risk of bridging, and enhances the yield of the package structure by stabilizing the conductive pillars and preventing collapse during reflow, thus improving manufacturing efficiency and cost-effectiveness.
Implementation Method 1
conductive pillars bonded to contact pads via a solder reflow process
Data Source
AI summary
Embodiments of mechanisms for forming a package are provided. The package includes a substrate and a contact pad formed on the substrate. The package also includes a conductive pillar bonded to the contact pad through solder formed between the conductive pillar and the contact pad. The solder is in direct contact with the conductive pillar.