Button Battery Integration in Semiconductor Packages at Low Temperature
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Solution Overview
Problem
Existing semiconductor devices face challenges in integrating small, non-rechargeable lithium button batteries internally due to size constraints and external mounting methods that add bulk and disrupt assembly flow, leading to reliability issues and potential battery degradation from high-temperature manufacturing processes.
Innovation Solution
A low-temperature manufacturing process integrates button batteries into semiconductor packages by using conductive tabs, forming apertures in conductive leads, applying a low-temperature conductive adhesive, and encapsulating with a low-temperature encapsulant to ensure battery performance is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If button batteries are externally mounted via sockets, tabs or clips, then the battery can be easily installed, but the device bulk increases and reliability decreases
Solution Approach 1:
The patent merges the battery mounting function with the semiconductor package structure by integrating the battery directly into the package cavity. The battery is positioned and secured within the molded package structure, eliminating the need for separate external mounting hardware such as sockets, tabs, or clips. This integration reduces device bulk while maintaining reliable electrical and mechanical connections through the package's built-in conductive leads and structural features.
2Ease of manufacture
If button batteries are externally mounted, then the assembly process is simple, but the assembly flow is interrupted and productivity decreases
Solution Approach 1:
The patent implements preliminary action by pre-forming the package structure with integrated battery mounting features during the molding process. The package is molded with cavities, conductive leads, and structural features that are specifically designed to receive and secure the battery. This allows the battery to be installed as part of the continuous assembly flow without interrupting the production process for separate mounting operations, thereby maintaining ease of manufacture while significantly improving productivity.
3Ease of manufacture
If high-temperature manufacturing processes are used, then the semiconductor devices can be fabricated, but the battery performance degrades
Solution Approach 1:
The patent applies segmentation by dividing the manufacturing process into distinct temperature zones and sequences. High-temperature semiconductor fabrication steps are performed first to create the package structure with integrated battery features. Then, the battery is installed and sealed within the package using low-temperature processes that do not exceed the battery's maximum operating temperature. This temporal and thermal segmentation allows both high-temperature semiconductor manufacturing and battery performance preservation to be achieved.
Solution Approach 2:
The patent implements beforehand cushioning by designing the package structure with thermal protection features before battery installation. The molded package structure includes insulation layers, thermal barriers, and sealed cavities that protect the battery from high-temperature exposure during subsequent semiconductor processing steps. This pre-engineered thermal protection allows the battery to withstand the manufacturing environment without performance degradation.
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 allows for internal battery integration without degrading performance, improving reliability and compatibility with high-volume production processes by avoiding high-temperature steps that damage batteries.
Implementation Method 1
A low temperature, conductive bonding agent, such as electrically conductive adhesive (ECA), is deposited into the channels formed by the cavities and apertures.
Implementation Method 2
The encapsulant is allowed to cure, and the individual semiconductor devices may then be singulated.
Data Source
AI summary
A self-powered microelectronic semiconductor device includes low temperature interconnection and encapsulation materials to enable integration of a battery with the microelectronics package during manufacture. The package includes a partially exposed leadframe or leads of a substrate for connecting the battery. The battery includes one or more terminal connectors that can either be manufactured by the battery vendor or externally attached using spot/laser or resistance welding. The steps of connecting the battery to the package are performed after the microelectronic package assembly to ensure the battery does not experience any high temperatures from the package assembly process. Cavities are formed in an overmolded molding compound to expose the leadframe or battery pads for electronic connection. A low temperature electrically conductive bonding agent is used to create the electrical and mechanical bond of the battery tabs to the leadframe. A low temperature encapsulant is then applied over the package and mounted battery.