Microelectronics Metal Substrate via Electroplating on Sacrificial Wafer
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Solution Overview
Problem
Existing methods for embedding sensors into high melting temperature metal matrix materials are technically difficult and commercially impractical due to surface discontinuities in commercially available metal substrates, which lead to sensor failures and high production costs.
Innovation Solution
A method for producing microelectronics-grade metal substrates using a sacrificial silicon wafer with a smooth adhesion layer and seed layer, followed by electroplating to form a continuous, low-roughness metal substrate, which eliminates surface defects and allows for the fabrication of functional thin-film sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available metal substrates are used for sensor fabrication, then the substrate provides structural support, but the surface discontinuities and deep cracks cause sensor failures
Solution Approach 1:
The patent applies preliminary action by depositing the insulating layer, sensor layers, and encapsulating layers onto the metal substrate before the substrate is fully processed. This sequence ensures that the sensor structure is formed on the metal surface while the substrate undergoes subsequent processing steps, allowing the sensor to be protected from surface defects that may develop later in the manufacturing process.
Solution Approach 2:
The patent implements beforehand cushioning by depositing a thick insulating layer (e.g., alumina) over the metal substrate surface before fabricating the sensor. This insulating layer acts as a cushioning barrier that compensates for surface discontinuities and deep cracks in the metal substrate, preventing these defects from reaching and damaging the sensor elements during subsequent processing and operation.
2Reliability
If an insulating layer is deposited on the metal substrate surface, then the sensor can be fabricated, but surface discontinuities leave gaps in the insulating layer causing sensor shorts
Solution Approach 1:
The patent implements beforehand cushioning by depositing a thick insulating layer (e.g., alumina) over the metal substrate surface before fabricating the sensor. This insulating layer acts as a cushioning barrier that compensates for surface discontinuities and deep cracks in the metal substrate, preventing these defects from reaching and damaging the sensor elements during subsequent processing and operation.
Solution Approach 2:
The patent applies parameter changes by controlling the deposition parameters of the insulating layer to ensure complete coverage over the metal substrate surface. By adjusting deposition conditions such as thickness, deposition rate, and surface preparation, the insulating layer is formed with sufficient continuity to bridge over surface discontinuities and prevent electrical shorts to the substrate.
3Ease of manufacture
If conventional metal substrate production methods are used, then production costs are reduced, but surface defects increase leading to high sensor failure rates
Solution Approach 1:
The patent applies preliminary action by depositing the insulating layer, sensor layers, and encapsulating layers onto the metal substrate before the substrate is fully processed. This sequence ensures that the sensor structure is formed on the metal surface while the substrate undergoes subsequent processing steps, allowing the sensor to be protected from surface defects that may develop later in the manufacturing process.
Solution Approach 2:
The patent implements beforehand cushioning by depositing a thick insulating layer (e.g., alumina) over the metal substrate surface before fabricating the sensor. This insulating layer acts as a cushioning barrier that compensates for surface discontinuities and deep cracks in the metal substrate, preventing these defects from reaching and damaging the sensor elements during subsequent processing and operation.
4Device complexity
If thin-film sensors are fabricated directly on metal substrate surface, then the sensor structure is simplified, but surface roughness causes fabrication failures
Solution Approach 1:
The patent applies the intermediary principle by introducing an insulating layer (e.g., alumina) as a mediator between the metal substrate and the thin-film sensor. This intermediate layer provides a smooth, electrically isolated surface for sensor fabrication, decoupling the sensor structure from the rough metal substrate surface and enabling successful thin-film deposition and patterning processes.
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 approach enables the production of functional thin-film sensors on a microelectronics-grade metal substrate, reducing surface defects and costs, and allows for embedding sensors into high melting temperature bulk materials, facilitating in-situ monitoring of mechanical and thermal properties.
Implementation Method 1
a smooth adhesion layer and seed layer, followed by electroplating
Implementation Method 2
followed by electroplating to form a continuous, low-roughness metal substrate
Data Source
AI summary
Fabricating a microelectronics grade metal substrate comprises forming the metal substrate on a sacrificial substrate. An adhesion layer can be deposited on or over the surface of the sacrificial substrate. A seed layer of the metal can be deposited on or over the adhesion layer. The metal material can be deposited on the seed layer by electroplating or other low-temperature, low-stress process to form a microelectronics-grade metal substrate. Thin film sensors and/or other microelectronic devices, followed by appropriate insulating layer(s), may be fabricated on or over the sacrificial substrate before forming the metal substrate. The sacrificial silicon substrate can then be etched away, leaving the microelectronics-grade metal substrate, and possibly the microelectronics device. Another insulating layer(s), followed by another adhesion layer, another seed layer and additional amounts of the material forming the metal substrate can then be deposited over the now-exposed microelectronics device to encapsulate it within a metal shell.