Metal Bond Pad Layout for Reducing Fusion Bonding Non-Bond Regions
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Solution Overview
Problem
Fusion bonding processes often result in tiny non-bond regions due to the Joule-Thomson effect during bond wave propagation, which can lead to incomplete bonding between package components.
Innovation Solution
The formation of metal pads on the package components with different properties than the dielectric layer disrupts bond wave propagation, reducing the Joule-Thomson effect and minimizing non-bond regions by controlling the size and pitch of these pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fusion bonding is performed at high temperature to bond package components together, then bonding strength is improved, but tiny non-bond regions occur due to the Joule-Thomson effect during bond wave propagation
Solution Approach 1:
The patent applies preliminary action by performing pre-bonding at a lower temperature before the high-temperature bonding process. This preliminary bonding step prepares the package components for subsequent high-temperature bonding while avoiding the Joule-Thomson effect that causes non-bond regions, thus ensuring both bonding strength and completeness.
Solution Approach 2:
The patent employs parameter changes by varying the temperature parameter through two distinct bonding stages: a lower temperature pre-bonding stage followed by a higher temperature bonding stage. This parameter variation allows the process to achieve complete bonding without encountering the Joule-Thomson effect problems at consistently high temperatures.
2Reliability
If pre-bonding is performed at lower temperature to prepare components, then bonding completeness is improved, but bonding strength is insufficient until high-temperature processing
Solution Approach 1:
The pre-bonding step at lower temperature serves as a preliminary action that ensures complete bonding coverage across package components before the high-temperature strengthening phase. This sequential approach guarantees that no regions are missed during bonding while achieving the required bond strength in the subsequent heating stage.
Solution Approach 2:
The bonding process uses periodic action by alternating between two temperature phases: a lower temperature pre-bonding phase for completeness and a higher temperature bonding phase for strength. This periodic temperature variation ensures both bonding completeness and adequate bonding strength are achieved.
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 effectively reduces or eliminates tiny non-bond regions, ensuring more reliable bonding between package components through the disruption of bond wave propagation and subsequent fusion bonding.
Implementation Method 1
Fusion bonding processes often result in tiny non-bond regions due to the Joule-Thomson effect during bond wave propagation
Data Source
AI summary
A method includes depositing a first dielectric layer as a first surface layer of a first package component, forming a plurality of metal pads in the first dielectric layer, depositing a second dielectric layer as a second surface layer of a second package component, and bonding the second package component to the first package component. The first dielectric layer is bonded to the second dielectric layer. At a time after the bonding, a metal pad in the plurality of metal pads has a top surface contacting a bottom surface of the second dielectric layer.