BGA Encapsulant Guard Ring Anti-Tamper Security
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anti-tamper mesh technologies in POS terminals are costly and complex, and there is a need for additional cost-effective measures to enhance the tamper-proof nature of these devices.
Innovation Solution
A package-on-package (POP) secure module assembly with encapsulant guard rings on BGA packages that form a peripheral strip around the edges, providing physical barriers and obscuring views of bond balls to impede unauthorized access and probing, while being applied in the same screen printing step as the encapsulant for integrated circuits, thus minimizing additional cost and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-tamper mesh is used to protect sensitive information, then security against tampering is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The anti-tamper protection is segmented into multiple independent layers: a traditional anti-tamper mesh within the POS terminal circuitry and an additional encapsulant guard ring structure surrounding the BGA packages. This segmentation allows each layer to provide protection independently, with the guard ring adding peripheral protection without requiring modification of the existing mesh structure, thereby improving security while maintaining manageable complexity
Solution Approach 2:
The encapsulant guard ring is nested within the existing package structure, forming a protective barrier between the substrate and the external environment. The guard ring is integrated into the package-on-package assembly, with the first BGA package containing the second BGA package, and the encapsulant forming a protective layer around both, creating a nested protective structure that enhances security without adding external complexity
2Reliability
If anti-tamper mesh is used to protect sensitive information, then security against tampering is improved, but manufacturing cost increases
Solution Approach 1:
The manufacturing process for the encapsulant guard ring is merged with the existing encapsulation process for the integrated circuits. The encapsulant material is applied in the same screen printing step used for IC encapsulation, combining two protective functions into a single manufacturing operation. This merging eliminates the need for separate guard ring fabrication steps, reducing manufacturing cost while maintaining the security benefit
Solution Approach 2:
The encapsulant material serves multiple functions simultaneously: it provides standard IC encapsulation protection and forms the additional anti-tamper guard ring structure. By making the encapsulant multi-functional, the patent eliminates the need for separate materials or processes dedicated solely to guard ring formation, thereby reducing manufacturing cost while maintaining enhanced security
3Reliability
If encapsulant guard rings are added to BGA packages, then anti-tamper security is improved, but device complexity increases
Solution Approach 1:
The encapsulant guard ring provides enhanced protection specifically at the peripheral region of the BGA packages, where side probing and tampering attempts are most likely to occur. The guard ring forms a closed loop around the peripheral edge, concentrating protective quality where it is most needed, while the central region maintains its standard structure. This localized quality enhancement improves anti-tamper security without requiring complex modifications throughout the entire device
Data Source
AI summary
A ball grid array (BGA) package (such as one BGA package of a package-on-package (POP) secure module assembly) includes a substrate, and integrated circuit, and array of bond balls. The BGA package further includes a first amount of encapsulant that covers the integrated circuit and a novel second amount of encapsulant. The novel second amount of encapsulant is a peripheral strip that extends along an edge of the substrate to form a peripheral guard ring. The peripheral guard ring provides an additional amount of anti-tamper security to the BGA package. The guard ring can be fabricated with no or very little additional cost if the guard ring is formed in the same encapsulation step employed to encapsulate the integrated circuit. In some embodiments, the peripheral guard ring is made part of and/or is coupled to anti-tamper circuitry such that if the guard ring is disturbed a tamper condition is detected.