Embedded ESD Protection in Package Substrates
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Solution Overview
Problem
Existing electronic component devices face challenges in providing robust electro-static discharge (ESD) protection, especially in high-density IC devices, as traditional methods require additional surface-mounted components, increasing size and cost, and often fail to provide sufficient protection.
Innovation Solution
Incorporating an ESD protection element within the package substrate, featuring a cavity portion with composite material and opposed discharge electrodes, and a dedicated ground electrode, which reduces thermal expansion differences and allows for adjustable discharge inception voltage, eliminating the need for separate surface-mounted components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate ESD protection component is mounted on the substrate surface, then robust ESD protection is achieved, but the substrate surface area must be large and cost increases
Solution Approach 1:
The patent merges the ESD protection function with the package substrate by embedding the ESD protection element inside the substrate body. The ESD protection element includes discharge electrodes formed within the substrate, eliminating the need for separate surface-mounted ESD components while maintaining robust protection capability
Solution Approach 2:
The invention transitions from two-dimensional surface mounting to three-dimensional embedding. The ESD protection element is positioned within the substrate's thickness dimension, utilizing the substrate's volume rather than requiring additional surface area. The discharge electrodes are formed at different depths within the substrate structure
2Reliability
If a separate ESD protection component is mounted on the substrate surface, then ESD protection is provided, but device cost increases
Solution Approach 1:
The ESD protection element is integrated into the package substrate manufacturing process. The discharge electrodes are formed using the same electrode formation steps as the signal and ground electrodes, and the ESD protection element is embedded during substrate fabrication, eliminating the need for separate component procurement and assembly
Solution Approach 2:
The package substrate serves multiple functions: it provides mechanical support, electrical interconnection through signal and ground electrodes, and ESD protection through the embedded ESD protection element. This multi-functionality eliminates the need for dedicated ESD protection components, reducing overall device cost
3Device complexity
If the ESD protection element uses metal discharge electrodes directly on the substrate, then simple structure is achieved, but thermal expansion mismatch causes separation and characteristic changes
Solution Approach 1:
The patent uses a composite material layer between the metal discharge electrodes and the substrate. This composite layer has a thermal expansion coefficient intermediate between that of the metal electrodes and the substrate material, reducing thermal stress during temperature cycling and preventing separation while maintaining structural simplicity
Solution Approach 2:
The invention addresses thermal expansion mismatch by selecting a composite material with appropriate thermal expansion properties. The composite layer's thermal expansion coefficient is chosen to be between that of the metal discharge electrodes and the substrate, compensating for differential expansion and contraction during temperature changes
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 configuration enables miniaturization of electronic component devices, reduces costs, and provides robust ESD protection without increasing the substrate's surface area or using additional components, effectively preventing damage from static electricity.
Implementation Method 1
the thermal coefficient of expansion of the composite portion is between that of the discharged electrodes and that of the package substrate, and the difference between the thermal coefficient of expansion of the discharged electrodes and that of the package substrate can be reduced by the composite portion
Implementation Method 2
the static electricity is discharged in the ESD protection component 103 and guided to the ground side, and thus, the IC element 102 is not damaged and no malfunction occurs
Data Source
AI summary
In an electronic component device, an ESD protection element including a cavity portion and a pair of opposed discharge electrodes is disposed inside a package substrate. A composite portion made of a composite material including a metal material and an insulating material is disposed on a bottom of the cavity portion. The package substrate including the ESD protection element disposed therein reduces the size of the electronic component device and reliably prevents damage to and malfunctioning of the electronic component device.