Dielectric Encasement for Semiconductor Solder Joint Reliability
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Solution Overview
Problem
Current semiconductor devices face reliability issues due to solder joint failures under thermal expansion, contraction, and mechanical shock, which can lead to device malfunction and corrosion, particularly in electronic devices like cellular phones.
Innovation Solution
A method and device using a photoimageable permanent dielectric material applied to semiconductor devices to create a protective seal by patterning the material to have openings over features, dispensing fluxing material, and applying solder to form a conformal seal around the solder joint during reflow, enhancing mechanical and thermal reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional semiconductor devices are used without dielectric encasement, then the device structure remains simple and manufacturing is easier, but the reliability under thermal expansion, contraction, and mechanical shock deteriorates
Solution Approach 1:
The patent embeds a layer of photoimageable permanent dielectric material within the semiconductor device structure, nesting it between the substrate and the solder joints. This nested dielectric layer provides mechanical support and protection against thermal and mechanical stress, thereby improving reliability without significantly altering the overall device architecture
Solution Approach 2:
The dielectric material is applied and patterned before the soldering process. By performing the dielectric encasement beforehand, the structure is pre-prepared to withstand subsequent thermal and mechanical stresses during soldering and device operation, preventing reliability issues before they occur
2Reliability
If a photoimageable permanent dielectric material layer is applied and patterned to create openings over features, then a protective seal is formed around solder joints, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces traditional mechanical sealing methods with a photoimageable dielectric material that can be precisely patterned using photolithography. This substitution allows for more accurate and reliable sealing around solder joints while utilizing standard semiconductor manufacturing processes
Solution Approach 2:
The dielectric material undergoes parameter changes through photoimaging, where specific areas are selectively removed or modified to create openings over features. This parameter change enables precise control of the sealing structure without requiring complex mechanical tooling or multiple manufacturing steps
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
The solution significantly increases the reliability of semiconductor devices by minimizing the impact of thermal and mechanical stress, protecting against corrosion, and ensuring a durable seal around the solder joint, thereby improving the overall performance and longevity of electronic devices.
Implementation Method 1
heating the semiconductor device to a reflow temperature appropriate for the reflow of the solder, thereby causing the solder to conform to sidewalls of the permanent dielectric material openings to form a protective seal
Data Source
AI summary
A method and device for enhanced reliability for semiconductor devices using dielectric encasement is disclosed. The method and device are directed to improving the reliability of the solder joint that connects the integrated circuit (IC) chip to the substrate. The method comprises applying a layer of a photoimageable permanent dielectric material to a top surface of the semiconductor device, and patterning the layer of the photoimageable permanent dielectric material to have an opening over each feature. The method further comprises dispensing or stencil printing fluxing material into the permanent dielectric material openings, and applying solder, which contains no flux, to a top surface of the fluxing material. In one or more embodiments, the method further comprises heating the semiconductor device to a reflow temperature appropriate for the reflow of the solder, thereby causing the solder to conform to sidewalls of the permanent dielectric material openings to form a protective seal.