Micromechanical Device Hydrogen Drainage Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydrogen diffusion from IC chips into MEMS cavities leads to internal pressure variations, causing manufacturing defects and lack of long-term stability in micromechanical sensors.
Innovation Solution
Incorporating a hydrogen drainage layer between the IC functional layer and the cavity, optionally combined with a hydrogen barrier layer and a perforated metal sealing ring, to direct hydrogen outgassing to the atmosphere and reduce internal pressure fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrogen barrier layer is applied to the IC chip to prevent hydrogen diffusion, then hydrogen protection of the cavity is improved, but the barrier layer must be structured to expose bond frame or chip-to-chip contacts creating permeable surfaces that reduce protection effectiveness
Solution Approach 1:
The protective function is segmented into two distinct layers: a hydrogen barrier layer (first protective layer) and a hydrogen drainage layer (second protective layer). The barrier layer provides primary protection while the drainage layer captures and redirects hydrogen that penetrates the barrier, eliminating the need for complex structuring of the barrier layer itself.
Solution Approach 2:
The hydrogen drainage layer acts as an intermediary between the IC chip and the cavity. It intercepts hydrogen diffusion paths, capturing hydrogen atoms before they can reach the cavity, and provides an alternative escape route to the outside environment.
2Ease of manufacture
If the IC chip uses standard manufacturing processes with metallic, semiconducting and dielectric layers, then device functionality is achieved, but hydrogen is trapped in the IC chip structure leading to diffusion into the cavity
Solution Approach 1:
The hydrogen that would normally be harmful by diffusing into the cavity is instead redirected through the drainage layer to escape externally. The drainage layer converts the harmful diffusion path into a beneficial external venting path, maintaining standard IC manufacturing processes while eliminating the harmful effect.
3Device complexity
If hydrogen is allowed to diffuse freely from the IC chip, then manufacturing simplicity is maintained, but internal pressure in the cavity varies leading to defective parts and lack of long-term stability
Solution Approach 1:
The dual-layer protective structure is implemented during the manufacturing stage to preemptively address hydrogen diffusion issues. The barrier and drainage layers are integrated into the IC chip structure before final assembly, ensuring internal pressure stability is maintained throughout the device's operational life.
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 solution effectively prevents hydrogen entry into the cavity, enhancing internal pressure stability and ensuring the long-term functionality of micromechanical sensors by discharging hydrogen externally and reducing the load on hydrogen barriers.
Implementation Method 1
At high temperatures or over a sufficiently long period of time, the hydrogen diffuses out of the IC chip, preferably in the direction of the sensor element.
Implementation Method 2
the IC chip comprises a hydrogen drainage layer which is disposed between the IC functional layer and the cavity
Data Source
AI summary
A micromechanical device. The device includes a MEMS chip which comprises a cavity; an IC chip which includes an IC substrate and at least one IC functional layer, wherein the IC chip is connected to the MEMS chip such that the IC functional layer is disposed between the IC substrate and the cavity. The IC chip includes a hydrogen drainage layer which is disposed between the IC functional layer and the cavity.