Porous Semiconducting Layer Thermal Isolation in Electronic Device Stacks
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Solution Overview
Problem
In the fabrication of electronic device stacks using CoolCube™ technology, thermal diffusion of heat from pulse laser irradiation through underlying oxide layers impairs the electronic devices, limiting the thermal budget and affecting the quality of transistors.
Innovation Solution
A method involving a porous second semiconducting layer for thermal isolation, allowing direct bonding between the dielectric layer and the porous second semiconducting layer, which reduces heat diffusion and enables flexible pulse laser parameters, enhancing thermal isolation and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pulse laser is used to thermally activate dopants, then dopant activation efficiency is improved, but thermal diffusion through oxide layers impairs the electronic device
Solution Approach 1:
A porous thermal isolation layer is introduced as an intermediary between the laser irradiation zone and the electronic device. This layer mediates the thermal interaction by absorbing and dissipating heat, preventing direct thermal diffusion to the sensitive electronic components while still allowing the laser to activate dopants in the target region.
Solution Approach 2:
The patent employs a porous semiconducting layer with controlled porosity (30-70% void ratio) as a thermal isolation barrier. The porous structure provides thermal insulation through air gaps that reduce heat conduction, protecting the underlying electronic device from laser-induced thermal damage while permitting the necessary thermal activation process.
2Strength
If direct bonding is performed between dielectric layers, then bonding strength is improved, but thermal isolation is reduced
Solution Approach 1:
The patent replaces the conventional solid dielectric layer with a porous semiconducting layer that provides both mechanical bonding capability and thermal isolation. The porous structure maintains bonding strength through surface adhesion while the void spaces filled with air provide thermal insulation, simultaneously addressing both requirements.
Solution Approach 2:
The thermal isolation layer is formed as a composite structure combining semiconducting material with porous architecture. This composite provides both the mechanical properties needed for direct bonding and the thermal properties needed for heat isolation, achieving dual functionality in a single layer.
3Reliability
If thermal budget is increased to activate dopants, then ground plane quality is improved, but electronic device integrity is compromised
Solution Approach 1:
The porous thermal isolation layer acts as a protective intermediary that allows high thermal budget processing for dopant activation without transmitting excessive heat to the electronic device. This enables achieving high-quality ground planes while maintaining device integrity through the thermal buffer provided by the porous structure.
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
The method significantly reduces thermal diffusion, allowing for a higher thermal budget and improved device quality by providing effective thermal isolation and mechanical strength, thus enabling better control over pulse laser parameters.
Implementation Method 1
such a porous second semiconducting layer enables a good thermal isolation of the first electronic device to be obtained
Implementation Method 2
one drawback is the thermal diffusion of the heat produced by the pulse laser in step f0), through the underlying oxide layers
Implementation Method 3
irradiating the first semiconducting layer or the active layer by a pulse laser so as to thermally activate the corresponding dopants
Implementation Method 4
thermally activate the dopants introduced in step e0)
Implementation Method 5
bonding the first and second structures by direct bonding between the dielectric layer and the porous second semiconducting layer
Data Source
AI summary
This method includes the following steps: a) providing a first structure successively including a substrate, an electronic device and a dielectric layer; b) providing a second structure successively including a substrate, an active layer, an intermediate layer, a first semiconducting layer and a porous second semiconducting layer; c) bonding the first and second structures by direct bonding between the dielectric layer and the porous second semiconducting layer; d) removing the substrate of the second structure so as to expose the active layer; e) adding dopants to the first semiconducting layer or to the active layer; f) irradiating the first semiconducting layer by a pulse laser so as to thermally activate the corresponding dopants.