Conductive Epoxy Bump Attachment for Semiconductor Contamination Control
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Solution Overview
Problem
The existing methods for forming a connection between semiconductor structures and carriers, such as SAW devices, often result in contamination of the semiconductor's bottom surface due to flux splashing during the solder reflow process.
Innovation Solution
A method involving the application of an electrically conductive epoxy portion with a diameter less than or equal to the bump's diameter, which is attached to the carrier's pad and cured to form a connection structure, thereby avoiding direct contact with the semiconductor's surface and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder reflow process is used to attach bumps to pads, then reliable electrical connection is achieved, but flux splashing causes contamination of the semiconductor bottom surface
Solution Approach 1:
The patent introduces a carrier as an intermediary component between the semiconductor structure and the mounting board. The carrier provides a platform for bump attachment that is separated from the semiconductor bottom surface, allowing solder reflow to occur without direct contamination of the semiconductor. The carrier effectively mediates the connection process while protecting the semiconductor structure from harmful flux exposure.
Solution Approach 2:
The patent segments the assembly process into distinct stages: first attaching bumps to the carrier, then mounting the semiconductor structure to the carrier. This segmentation allows the solder reflow process to be isolated to the carrier-bump interface, preventing flux from reaching the semiconductor bottom surface while maintaining connection reliability.
2Object-affected harmful factors
If epoxy is applied to the pad for bump attachment, then contamination is avoided, but precise control of epoxy diameter is required to match bump dimensions
Solution Approach 1:
The patent specifies that the epoxy diameter should be less than or equal to the bump diameter, creating a controlled parameter relationship. This parameter control ensures that the epoxy is sufficient to attach the bump while preventing excess epoxy from spreading and contaminating the semiconductor bottom surface. The diameter constraint is a key parameter change that resolves the contamination issue.
Solution Approach 2:
The patent applies epoxy in a controlled amount that is partial rather than excessive - specifically, the epoxy diameter is limited to be less than or equal to the bump diameter. This partial application is sufficient for achieving reliable bump attachment while avoiding the harmful effects of excess epoxy spreading and contaminating the semiconductor structure.
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 eliminates the need for a conventional solder reflow process, minimizing contamination and ensuring reliable assembly of the semiconductor structure on the carrier while maintaining performance by controlling the epoxy's viscosity and resistance.
Implementation Method 1
A method involving the application of an electrically conductive epoxy portion with a diameter less than or equal to the bump's diameter, which is attached to the carrier's pad and cured to form a connection structure
Data Source
AI summary
A method for forming a connection structure is disclosed. A semiconductor structure having a first pad and a bump respectively on a bottom surface thereof is provided. A carrier having a second pad on a top surface thereof is provided. The second pad corresponds to the bump. An epoxy portion is disposed onto the second pad of the carrier. A diameter of the epoxy portion is less than or equal to a diameter of the bump. After depositing the epoxy portion, the bump is attached to the second pad via the epoxy portion.