Vacuum Relief Bonding Nozzle for Thermal Expansion Alignment
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Solution Overview
Problem
Thermal compression bonding tools face misalignment and warpage issues due to non-uniform thermal expansion and contraction of dies relative to substrates, caused by pinning at the corners and edges of vacuum nozzles, leading to significant gaps and misalignment of interconnects during the reflow process.
Innovation Solution
A vacuum bonding nozzle with peripheral vacuum relief conduits that weaken the vacuum seal at the periphery, allowing for free thermal expansion and contraction, while maintaining adequate clamping force in the central region to align dies with substrates, using a network of interconnected channels and vacuum gradients to distribute clamping forces radially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong vacuum clamping is applied at the periphery of the die, then the die is securely held in place during bonding, but thermal expansion and contraction are constrained causing misalignment and warpage
Solution Approach 1:
The vacuum nozzle applies different vacuum forces to different regions of the die: strong vacuum clamping in the central region to secure the die during bonding, and reduced vacuum force at the periphery through vacuum relief conduits to allow free thermal expansion and contraction. This spatial variation in vacuum force resolves the contradiction between holding stability and alignment accuracy.
2Reliability
If uniform vacuum clamping is applied across the entire die surface, then the die is firmly secured to the nozzle, but non-uniform thermal expansion occurs leading to warpage and bonding plane gaps
Solution Approach 1:
The vacuum relief conduits create local variations in vacuum force distribution across the die surface. The central region experiences strong vacuum clamping while peripheral regions experience reduced vacuum force, allowing differential thermal expansion without warpage and maintaining die flatness during the bonding process.
3Measurement precision
If strong vacuum force is applied to prevent die movement, then alignment is maintained during positioning, but thermal expansion is restricted causing misalignment during heating
Solution Approach 1:
The vacuum force distribution is made dynamic through the vacuum relief conduits, transitioning from uniform strong vacuum for initial positioning to a gradient distribution during heating where peripheral vacuum is relieved. This allows the system to adapt to different process stages: strong clamping for alignment, then controlled release for thermal expansion freedom.
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 solution reduces misalignment and warpage, achieving better alignment and reducing gaps between die and substrate interconnects, enhancing product yields by allowing unrestrained thermal expansion and contraction of the die during the bonding process.
Implementation Method 1
such tools may comprise a vacuum nozzle to hold a die in place by vacuum clamping the die to the nozzle
Implementation Method 2
using a network of interconnected channels and vacuum gradients to distribute clamping forces radially
Implementation Method 3
the alignment accuracy between die and substrate interconnects may be degraded by non-uniform thermal expansion and contraction of the die relative to the substrate during the reflow operation
Data Source
AI summary
An apparatus comprising a bonding nozzle that has one or more channels in a bonding surface. The one or more channels comprise a first channel portion in an inner region of the bonding surface and a second channel portion along an outer periphery of the bonding surface. The one or more channels are in fluid communication with a vacuum port. A vacuum relief conduit within the bonding nozzle comprises a first opening into the second channel portion along the outer periphery of the bonding surface, and a second opening along an exterior wall of the bonding nozzle.