Conductive Pillar Barrier Layer for Uniform Solder Joint Height
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Solution Overview
Problem
Existing semiconductor device packages face issues with uneven joint heights and tilting of conductive elements due to the flow of connection materials during reflow, leading to non-wetting or insufficient soldering, which affects electrical performance.
Innovation Solution
A semiconductor device package design featuring a conductive pillar with a barrier layer and encapsulants, where the barrier layer confines the flowable conductive material to a controlled height, preventing it from contacting the conductive pillar's surface and jointing with other contacts, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If connection elements are used to attach conductive elements to pads through solder, then electrical connection is achieved, but the connection elements flow away during reflow causing uneven joint height and tilting
Solution Approach 1:
The barrier layer is formed on the conductive pillar surface before the reflow process. This preliminary action creates a physical and chemical barrier that prevents the solder from wetting and flowing up the pillar surface, thereby maintaining uniform joint heights and preventing tilting during the subsequent reflow process.
Solution Approach 2:
The barrier layer acts as an intermediary between the conductive pillar and the solder material. It selectively prevents solder from interacting with the conductive pillar surface, controlling the solder flow behavior and ensuring proper joint formation without unwanted adhesion to the pillar.
2Ease of manufacture
If connection elements are allowed to flow during reflow, then soldering process is simplified, but conductive elements tilt and joint heights become uneven
Solution Approach 1:
The barrier layer is prepared in advance on the conductive pillar surface before soldering. This preliminary protective layer enables the solder to flow freely during reflow without adhering to the pillar, maintaining the conductive element's vertical orientation and preventing tilting while preserving process simplicity.
Solution Approach 2:
The barrier layer serves as an intermediary that decouples the solder flow behavior from the conductive pillar surface. It allows the solder to spread and form joints without creating unwanted adhesive forces that would cause the conductive elements to tilt or deform.
3Manufacturing precision
If barrier layer is added to prevent material flow, then joint height control is improved, but device structure complexity increases
Solution Approach 1:
The barrier layer is formed as a preliminary step in the manufacturing process using standard thin-film deposition techniques. This approach integrates smoothly into existing fabrication workflows, adding minimal process steps while achieving precise joint height control without significantly increasing overall device complexity.
Solution Approach 2:
The barrier layer modifies the surface properties of the conductive pillar by changing its material composition and surface energy characteristics. This parameter change prevents solder wetting and controls joint formation, achieving precise height control through material property modification rather than complex mechanical structures.
4Reliability
If flowable conductive material is used to ensure good wetting, then electrical connection is enhanced, but material flows onto conductive pillar surface causing non-wetting issues
Solution Approach 1:
The barrier layer creates a localized difference in surface properties on the conductive pillar. The areas covered by the barrier layer are non-wetting to solder, while the pad areas remain wetting. This local quality differentiation ensures proper solder flow to pads while preventing unwanted flow onto the conductive pillar surface.
Solution Approach 2:
The barrier layer acts as an intermediary that spatially separates the wetting behavior of the solder. It allows the solder to wet and adhere to the pad surfaces while preventing wetting of the conductive pillar surface, thereby eliminating non-wetting issues through selective surface property control.
Data Source
AI summary
The present disclosure provides a semiconductor device package. The semiconductor device package includes a conductive pillar having a first surface, a second surface, and a lateral surface extending between the first surface and the second surface. The lateral surface has a first part and a second part connected to the first part. The semiconductor device package also includes a barrier layer in contact with the first part of the lateral surface of the conductive pillar and an encapsulant in contact with the second part of the lateral surface of the conductive pillar. The semiconductor device package also includes a first flowable conductive material disposed on the first surface of the conductive pillar. A method of manufacturing a semiconductor device package is also disclosed.