Shielding Structure for Alpha Particle Protection in IC Packaging
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Solution Overview
Problem
Solder bumps used in integrated circuits emit alpha particles due to radioactive impurities, which can corrupt data by striking IC devices, and existing materials fail to adequately shield against these emissions.
Innovation Solution
A shielding structure is positioned between the solder bumps and IC devices, comprising a first and second shielding structure electrically coupled to the pad structure and under-ball metallization, respectively, to block alpha particles, with the second shielding structure being electrically isolated from the solder bump and positioned proximal to it for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder bumps with radioactive impurities are used to connect semiconductor die with package substrate, then electrical connection and mechanical bonding are achieved, but alpha particles are emitted that can strike IC devices and corrupt data
Solution Approach 1:
A shielding structure comprising conductive and insulative layers is introduced as an intermediary between the solder bump and the IC device. The conductive layer is electrically connected to the pad structure while the insulative layer provides electrical isolation, creating a protective barrier that blocks alpha particles from reaching the IC device while maintaining electrical connection functionality
Solution Approach 2:
The shielding structure utilizes composite construction with multiple layers including conductive material layers and insulative material layers. This composite structure combines the benefits of electrical connectivity (through conductive layers) with alpha particle shielding (through the layered configuration), effectively addressing both the electrical connection requirement and the harmful radiation emission
2Object-affected harmful factors
If shielding structures are added between solder bumps and IC devices, then alpha particle protection is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The shielding structure serves multiple functions simultaneously: it provides alpha particle shielding, maintains electrical connection through the conductive layer connected to the pad structure, and provides electrical isolation through the insulative layer. By combining these functions into a single integrated structure, the complexity is minimized while achieving comprehensive protection and functionality
Solution Approach 2:
The conductive layer and insulative layer are merged into a single shielding structure assembly that is deposited and patterned together. This combined structure integrates the shielding function with the electrical connection and isolation requirements, reducing the need for separate components and simplifying the overall device architecture
3Object-affected harmful factors
If shielding structures are positioned close to solder bumps for enhanced protection, then alpha particle blocking is improved, but electrical isolation requirements become more stringent
Solution Approach 1:
The insulative layer acts as an intermediary between the conductive layer (connected to pad structure) and the solder bump. This insulative barrier prevents direct electrical contact between the shielding structure and the solder bump, ensuring electrical isolation while allowing the shielding structure to be positioned close to the solder bump for effective alpha particle blocking
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 shielding structures effectively reduce alpha particle exposure to IC devices, minimizing data corruption and ensuring reliable operation despite the presence of alpha-emitting solder bump materials.
Implementation Method 1
solder bumps used to connect a semiconductor die with a package substrate (e.g., flip-chip packaging) to form a 'package'. Many solderable materials for solder bump applications including, for example, solder paste, have radioactive impurities that undergo radioactive decay, emitting alpha particles in the process
Implementation Method 2
the first shielding structure is positioned between the solder bump and the plurality of integrated circuit devices to shield the plurality of integrated circuit devices from the alpha particles
Data Source
AI summary
Embodiments of the present disclosure provide an apparatus including a semiconductor die having a plurality of integrated circuit devices, a pad structure electrically coupled to at least one integrated circuit device of the plurality of integrated circuit devices via an interconnect layer, an electrically insulative layer disposed on the interconnect layer, a first shielding structure disposed in the electrically insulative layer and electrically coupled to the pad structure, an under-ball metallization (UBM) structure electrically coupled to the first shielding structure, and a solder bump electrically coupled to the UBM structure, the solder bump comprising a solder bump material capable of emitting alpha particles, wherein the first shielding structure is positioned between the solder bump and the plurality of integrated circuit devices to shield the plurality of integrated circuit devices from the alpha particles. Other embodiments may be described and/or claimed.