CMOS Poly Heater Thermal Isolation via Thick Oxide Layer
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Solution Overview
Problem
Conventional CMOS manufacturing methods face limitations such as insufficient oxide layer thickness for isolation and heat dissipation, inability to utilize the poly gate as a poly heater, and suboptimal heat efficiency of interlayer dielectric layers.
Innovation Solution
A manufacturing method that employs an oxide layer thicker than 1 micrometer for isolation and heat-isolation regions, forms the poly gate as part of the poly heater, and utilizes a multi-layer structure of oxide and nitride with selenium etching to optimize heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oxide layer thickness is increased to be used as isolation region and heat-isolation region, then the isolation performance and heat dissipation capability are improved, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The oxide layer is designed to perform multiple functions simultaneously: electrical isolation between semiconductor regions and thermal isolation for the poly heater. By making the oxide layer thicker than 1 micrometer, it satisfies both isolation requirements with a single structure, avoiding the need for separate isolation layers and reducing overall manufacturing complexity.
Solution Approach 2:
The oxide layer thickness is changed from conventional thin dimensions to greater than 1 micrometer. This parameter change enables the oxide layer to provide adequate thermal isolation while maintaining electrical isolation, resolving the contradiction between isolation performance and manufacturing complexity.
2Use of energy by moving object
If the poly gate is formed as part of the poly heater, then the heat efficiency and utilization of the poly gate are improved, but the manufacturing precision and process control difficulty increase
Solution Approach 1:
The poly gate and poly heater are merged into a single integrated structure. The poly gate electrode serves dual purposes: as the control electrode for the transistor and as the heating element. This integration improves heat efficiency by directly utilizing the gate structure for heating, eliminating the need for separate heater electrodes.
Solution Approach 2:
The poly gate structure is designed to perform multiple functions: electrical control of the transistor channel and thermal heating of the underlying region. This multi-functionality improves energy utilization while the shared fabrication process maintains manufacturing precision.
3Use of energy by moving object
If a multi-layer structure of oxide and nitride is used for interlayer dielectric layer, then the heat efficiency is improved, but the device complexity and manufacturing steps increase
Solution Approach 1:
The interlayer dielectric structure uses composite materials with different thermal properties: oxide layers for thermal isolation and nitride layers for thermal conduction. By strategically combining these materials in multiple layers (ON, ONO, ONON structures), the system optimizes heat efficiency while maintaining structural integrity.
Solution Approach 2:
Different regions of the interlayer dielectric structure have different thermal conductivities tailored to local requirements. Nitride layers provide thermal conduction paths where heating is needed, while oxide layers provide thermal isolation where required. This localized optimization of thermal properties improves overall heat efficiency.
4Reliability
If the rest thickness of the poly heater is adjusted through selenium etching, then the heat-dissipating efficiency is optimized, but the manufacturing precision and process complexity increase
Solution Approach 1:
The poly heater thickness is made adjustable and optimizable rather than fixed. By introducing a selenium etching process, the remaining thickness of the poly heater can be tuned after initial formation, allowing optimization of heat-dissipating efficiency for different application requirements while maintaining manufacturing control.
Solution Approach 2:
The selenium etching process enables dynamic adjustment of the poly heater thickness parameter. By controlling the etching conditions, the remaining thickness can be optimized to achieve desired heat-dissipating efficiency, transforming a fixed parameter into an optimizable one.
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 heat efficiency and allows the poly gate to be effectively used as a poly heater, improving heat-dissipation capabilities and making CMOS manufacturing more efficient and competitive.
Implementation Method 1
the oxide layer is applied so as to be the isolation region of the metal oxide semiconductor region and a heat-isolation region of the poly heater
Implementation Method 2
adjusting the rest thickness of the multi-layer structure of the nitride and the oxide (i.e. the ONON structure of the poly heater) through the selenium etching process
Data Source
AI summary
A manufacturing method of a complementary metal oxide semiconductor includes steps as following: providing a semiconductor substrate; forming a metal oxide semiconductor region having an oxide layer, which has a thickness greater than 1 micrometer, on a first surface of the semiconductor substrate; forming the oxide layer as an isolation region of the metal oxide semiconductor region and a heat-isolation region of a poly heater; forming a poly gate of the metal oxide semiconductor region as at least a portion of the poly heater; forming an interlayer dielectric layer; and processing a selenium etching. Under this circumstance, the oxide layer is applied so as to be the isolation region of the metal oxide semiconductor region and a heat-isolation region of the poly heater, the poly gate of the metal oxide semiconductor region is sufficiently utilized as the poly heater, and the heat-dissipation of the poly heater is optimized.