Chip-Scale Atomic Clock Physics Package Fluxless Vacuum Sealing
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Solution Overview
Problem
Current chip-scale atomic clock physics packages face challenges in achieving low power operation and efficient vacuum sealing without using flux, which affects the reliability and performance of the components within the sealed package.
Innovation Solution
The design incorporates a ceramic body with a non-magnetic lid sealed using a solder seal, along with scaffolds fabricated using semiconductor processes, and a getter film to maintain a vacuum environment, allowing for fluxless die attach and batch vacuum sealing, thereby supporting low power operation and reducing thermal expansion-related fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flux is used for die attach in vacuum sealing, then sealing efficiency is improved, but component reliability deteriorates due to flux contamination
Solution Approach 1:
The invention removes flux entirely from the die attach process by using solder bump joints that can be formed without flux. The solder bumps are created through a fluxless soldering process, extracting the harmful flux substance from the manufacturing workflow while maintaining effective electrical and mechanical connections between components and the substrate.
Solution Approach 2:
The invention introduces solder bumps as an intermediary element between the component leads and the substrate pads. These solder bumps serve as mediators that provide both electrical connection and mechanical bonding without requiring flux, thus resolving the contradiction between sealing efficiency and component reliability by eliminating flux contamination while maintaining effective joints.
2Use of energy by moving object
If power consumption is reduced for low power operation, then energy efficiency is improved, but thermal management becomes more challenging
Solution Approach 1:
The invention replaces traditional thermal management approaches with a thermally conductive substrate that passively conducts heat away from the atomic clock components. Instead of active cooling mechanisms, the substrate's thermal conductivity is optimized to efficiently transfer heat from the low-power components to the surrounding environment, maintaining thermal management effectiveness even at reduced power levels.
3Volume of moving object
If multiple components are integrated in a compact package, then device miniaturization is improved, but manufacturing complexity increases
Solution Approach 1:
The invention segments the atomic clock system into distinct functional modules (vapor cell, laser, photodetector, electronics) that are independently fabricated and then integrated onto a common substrate using standardized solder bump connections. This segmentation allows each component to be optimized and manufactured separately using standard semiconductor processes, reducing overall manufacturing complexity while achieving compact integration.
Solution Approach 2:
The substrate serves multiple functions simultaneously: it provides mechanical support for all components, establishes electrical connections through solder bumps, manages thermal pathways, and defines the vacuum seal boundaries. This multi-functionality reduces the number of separate structures needed, simplifying manufacturing while achieving compact integration of all atomic clock components.
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 efficient vacuum sealing and low power operation of chip-scale atomic clock components, enhancing the reliability and performance by minimizing thermal expansion issues and maintaining a stable vacuum environment.
Implementation Method 1
The cavity can include a base surface and one or more side walls. The body can be hermetically seal to create a vacuum within the body.
Implementation Method 2
along with a getter film to maintain a vacuum environment
Data Source
AI summary
In an example, a chip-scale atomic clock physics package is provided. The physics package includes a body defining a cavity having a base surface and one or more side walls. The cavity includes a first step surface and a second step surface defined in the one or more side walls. A first scaffold mounted to the base surface in the cavity. One or more spacers defining an aperture therethrough are mounted to the second step surface in the cavity. A second scaffold is mounted to a first surface of the one or more spacers spans across the aperture of the one or more spacers. A third scaffold is mounted to a second surface of the one or more spacers in the cavity and spans across the aperture of the one or more spacers. Other components of the physics package are mounted to the first, second, and third scaffold.