Tapered Template Underfill Dispensing for Narrow Chip Gaps
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Solution Overview
Problem
The challenge in dispensing underfill material between closely spaced semiconductor chips is that the gap becomes smaller than the diameter of the underfill dispenser needle, making it difficult to effectively fill the gap with existing methods.
Innovation Solution
A template with tapered openings is used to inject underfill material into gaps narrower than the dispenser needle, accompanied by compliant material layers for accommodation and sealing, and an optional compressed gas to facilitate material flow, allowing simultaneous injection from multiple heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gap width between semiconductor chips is reduced to increase substrate utilization, then chip density and manufacturing efficiency are improved, but the gap becomes too small for needle insertion and underfill material dispensing
Solution Approach 1:
A template structure is introduced as an intermediary component between the injector needle and the gap. The template includes a funnel-shaped opening that receives the needle and channels the underfill material into the narrow gap between chips. This mediator enables the needle to access and dispense material into gaps smaller than the needle diameter would normally allow.
Solution Approach 2:
The solution transitions from a one-dimensional needle insertion approach to a multi-dimensional dispensing system. The template structure provides a three-dimensional pathway with a funnel-shaped opening that guides material flow from the needle through multiple spatial dimensions into the narrow gap, enabling material delivery without direct needle penetration into the gap.
2Ease of manufacture
If a template with tapered openings is used to enable needleless underfill dispensing, then gap filling capability is improved, but device complexity increases
Solution Approach 1:
The template structure is segmented into distinct functional components: a body portion that positions the openings, funnel-shaped openings that guide material flow, and a base portion that interfaces with the substrate. This segmentation allows each component to be optimized independently and facilitates manufacturing while maintaining the gap filling capability.
Solution Approach 2:
The template structure serves multiple functions simultaneously: it positions the underfill material delivery openings, guides material flow through its funnel shape, provides structural support, and interfaces with the substrate. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 method enables efficient filling of narrow gaps between semiconductor chips, increasing chip density and reducing manufacturing costs by allowing underfill material to be dispensed into spaces inaccessible with traditional dispensers.
Implementation Method 1
at least one lower compliant material portion can be employed to accommodate variations in distance between the template and stacked semiconductor chips bonded to a substrate
Implementation Method 2
an upper compliant material portion can be employed to seal an injector head against top surfaces of the stacked semiconductor chips
Implementation Method 3
Another head can be employed to apply compressed gas to push out the underfill material after the underfill material is applied to the gaps
Data Source
AI summary
A template having tapered openings can be employed to enable injection of underfill material through gaps having a width less than a lateral dimension of an injector needle for the underfill material. Each tapered opening has a first lateral dimension on an upper side and a second lateral dimension on a lower side. Compliant material portions can be employed to accommodate variations in distance between the template and stacked semiconductor chips and/or an injector head. Optionally, another head can be employed to apply compressed gas to push out the underfill material after the underfill material is applied to the gaps. Multiple injector heads can be employed to simultaneously inject the underfill material at different sites. An adhesive layer can be substituted for the at least one lower compliant material portion.