Semiconductor Underfill Control via Segmented Conductive Pillars

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Solution Overview

Problem

Conventional semiconductor die packaging processes often result in voids and excess underfill material, compromising the sealing integrity and interfering with subsequent manufacturing processes.

Innovation Solution

Incorporating conductive structures of varying heights and a non-conductive material that complements the substrate profile, allowing for uniform underfill distribution and reduced excess material, thereby enhancing the sealing and stacking capabilities of semiconductor devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pressure is applied to fill the cavity with underfill material, then the sealing function is improved, but voids form in the cavity compromising integrity

Engineering Contradiction:

Improvesealing integrityVSAvoidvoid formation

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The cavity is divided into multiple regions by introducing intermediate structures (such as support pillars or partition walls) that segment the filling space. This allows underfill material to be introduced and distributed in controlled segments, preventing void formation while maintaining sealing integrity throughout the cavity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Intermediate support structures are pre-positioned within the cavity before underfill material is applied. These pre-positioned structures guide the flow and distribution of underfill material, ensuring complete cavity filling without voids and eliminating the need for high-pressure application that would compromise sealing integrity.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If pressure is applied to distribute underfill material, then filling completeness is improved, but excess material squeezes out around die edges

Engineering Contradiction:

Improvefilling completenessVSAvoidexcess underfill material

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The cavity includes regions with different properties - some areas have higher capacity or different flow characteristics. By designing the cavity with varying local qualities (such as expanded regions or channels of different cross-sections), underfill material is directed to fill specific areas efficiently without being forced outward, reducing excess material while maintaining complete filling.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Intermediary structures such as flow control barriers or guide walls are introduced within the cavity to mediate the flow of underfill material. These intermediaries channel the material along predetermined paths, ensuring complete cavity filling while preventing material from reaching and squeezing out around the die edges.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If conventional underfill process is used, then sealing function is provided, but excess material interferes with subsequent manufacturing processes

Engineering Contradiction:

Improvesealing functionVSAvoidsubsequent process interference

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The harmful excess underfill material is extracted or prevented from forming in the first place by designing the cavity with controlled volume and flow paths. The cavity geometry is optimized to accommodate the underfill material within defined boundaries, preventing material from escaping to interfere with subsequent manufacturing processes while maintaining the sealing function.

Inventive Principle:

Principle #2Taking out (Extraction)

4Productivity

If die and substrate are brought together with cavity filling, then electrical connections are formed, but voids compromise connection integrity

Engineering Contradiction:

Improveconnection formationVSAvoidconnection integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The cavity filling process is segmented into controlled stages using intermediate structures. These structures divide the cavity into regions that can be filled sequentially or simultaneously in a controlled manner, ensuring that underfill material reaches all areas including around conductive pillars without forming voids that would compromise electrical connection integrity.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10784224B2Semiconductor devices with underfill control features, and associated systems and methods

Publication Date: 2020.09.22 MICRON TECHNOLOGY INC

AI summary

Semiconductor devices with underfill control features, and associated systems and methods. A representative system includes a substrate having a substrate surface and a cavity in the substrate surface, and a semiconductor device having a device surface facing toward the substrate surface. The semiconductor device further includes at least one circuit element electrically coupled to a conductive structure. The conductive structure is electrically connected to the substrate, and the semiconductor device further has a non-conductive material positioned adjacent the conductive structure and aligned with the cavity of the substrate. An underfill material is positioned between the substrate and the semiconductor device. In other embodiments, in addition to or in lieu of the con-conductive material, a first conductive structure is connected within the cavity, and a second conductive structure connected outside the cavity. The first conductive structure extends away from the device surface a greater distance than does the second conductive structure.