Motion Sensor Robustness via RTV Material and Solder Resist Dam
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor technologies using die attach films transfer mechanical stress to motion sensor devices, leading to reduced performance due to external temperature and force applications.
Innovation Solution
Employing a room-temperature-volcanizing (RTV) material via solder resist dams to attach semiconductor dies to substrates, which absorbs and isolates external stress, maintaining elasticity and improving sensor robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a die attach film (DAF) is used to connect the semiconductor die to the substrate, then the semiconductor die can be securely attached to the substrate, but mechanical stress from temperature and force applications is directly transferred to the semiconductor die, reducing sensor performance
Solution Approach 1:
The patent introduces an intermediary substance (mold compound or underfill material) between the die attach film and the semiconductor die. This intermediary layer absorbs and dissipates mechanical stress from thermal expansion and physical forces, preventing direct stress transfer to the sensitive semiconductor die while maintaining secure attachment to the substrate.
Solution Approach 2:
The patent employs composite material structures combining the die attach film with overlying mold compound or underfill materials. This composite approach leverages the strong adhesive properties of the DAF for attachment while the softer, more compliant mold compound or underfill provides stress relief, creating a multi-functional attachment system that protects sensor performance.
2Ease of manufacture
If conventional die attach methods are used, then manufacturing simplicity is maintained, but sensor robustness against external stress and temperature variations deteriorates
Solution Approach 1:
The patent applies mold compound or underfill material in advance during the packaging process, before the device undergoes thermal cycling or mechanical stress. This preliminary protective layering ensures that when temperature and force variations occur during operation, the stress-absorbing materials are already in place to protect the semiconductor die, eliminating the need for complex active compensation mechanisms.
3Device complexity
If the semiconductor die is directly attached to the substrate, then device complexity is minimized, but the sensor becomes vulnerable to mechanical stress from temperature and force applications
Solution Approach 1:
The patent implements beforehand cushioning by placing mold compound or underfill materials between the substrate and semiconductor die during manufacturing. These materials act as pre-positioned cushioning layers that absorb mechanical stress and thermal expansion forces before they can reach the semiconductor die, protecting against harmful factors without adding complex active protection systems.
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
Enhances sensor performance by effectively absorbing and isolating external stress, as demonstrated in tumble and drop tests within specified temperature ranges, improving device reliability.
Implementation Method 1
the RTV material that is disposed between the monolithic die and the substrate... maintaining elasticity and improving sensor robustness
Implementation Method 2
room-temperature-volcanizing (RTV) material... disposing, during a defined viscous state of the RTV material
Data Source
AI summary
Improving motion sensor robustness utilizing a room-temperature-volcanizing (RTV) material via a solder resist dam is presented herein. A sensor package comprises: a first semiconductor die; a second semiconductor die that is attached to the first semiconductor die to form a monolithic die; and a substrate comprising a top portion and a bottom portion, in which the top portion comprises a plurality of solder resist dams, the monolithic die is attached to the top portion of the substrate via the RTV material being disposed in a defined area of the top portion of the substrate, and the bottom portion of the substrate comprises electrical terminals that facilitate attachment and electrical coupling of signals of the sensor package to a printed circuit board.