Semiconductor Bio-Sensor Integration with CMOS via Sacrificial Oxide
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Solution Overview
Problem
The integration of semiconductor bio-sensors with CMOS devices is challenging due to the vulnerability of thin insulator and conductor layers to damage during the CMOS process, necessitating a method to protect and manufacture bio-sensors effectively within this context.
Innovation Solution
A method involving the sequential formation of dielectric and conductive layers, with specific etching processes to create cavities and vias, followed by passivation, allowing for the integration of bio-sensors with CMOS devices on a single wafer, ensuring protection and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bio-sensors are integrated with CMOS devices on a single wafer, then productivity and device integration are improved, but the thin insulator and conductor layers of bio-sensors are vulnerable to damage during the CMOS process
Solution Approach 1:
A sacrificial oxide layer is introduced as an intermediary between the bio-sensor layers and the CMOS process environment. This sacrificial layer absorbs the harsh etching conditions, protecting the underlying thin insulator and conductor layers of the bio-sensor during CMOS fabrication while enabling wafer-level integration
Solution Approach 2:
The method applies beforehand cushioning by forming a protective sacrificial oxide layer prior to the CMOS processing steps. This pre-established protective barrier cushions the vulnerable bio-sensor layers against damage from subsequent etching and processing operations in the CMOS fabrication sequence
2Ease of manufacture
If standard CMOS processing is applied to bio-sensors, then manufacturing complexity is reduced, but the thin insulator and conductor layers are easily damaged
Solution Approach 1:
The sacrificial oxide layer serves as a mediator that allows standard CMOS processing to be applied without directly exposing the thin bio-sensor layers to harmful etchants. It absorbs the harmful effects while enabling the use of conventional manufacturing processes
Solution Approach 2:
The method converts the potentially harmful etching processes into a beneficial protective mechanism. The sacrificial oxide layer is deliberately designed to be etched away, using the harmful etchants to remove the sacrificial layer while leaving the underlying bio-sensor layers protected and intact
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 method enables the reliable integration and protection of bio-sensors within the CMOS process, maintaining their integrity and functionality, thus facilitating their use alongside other semiconductor devices.
Implementation Method 1
forming cavities into the fourth dielectric layer by an isotropic etch
Implementation Method 2
forming vias through the cavities by an anisotropic etch
Data Source
AI summary
A method of manufacturing a semiconductor bio-sensor comprises providing a substrate, forming a first dielectric layer on the substrate, forming a patterned first conductive layer on the first dielectric layer, the patterned first conductive layer including a first portion and a pair of second portions, forming a second dielectric layer, a third dielectric layer and a fourth dielectric layer in sequence over the patterned first conductive layer, forming cavities into the fourth dielectric layer, forming vias through the cavities, exposing the second portions of the patterned first conductive layer, forming a patterned second conductive layer on the fourth dielectric layer, forming a passivation layer on the patterned second conductive layer, forming an opening to expose a portion of the third dielectric layer over the first portion of the patterned first conductive layer, and forming a chamber through the opening.