Stacked Substrate Structure for Laser Debonding Without Substrate Damage
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Solution Overview
Problem
The separation of a support substrate in semiconductor devices, such as three-dimensional nonvolatile memory, using thermal expansion can cause damage like lattice defects due to direct thermal expansion of the semiconductor substrate, reducing the substrate's reusability.
Innovation Solution
A stacked substrate design incorporating a phosphorus-doped polysilicon layer and insulating layers, where the polysilicon layer absorbs laser light to thermally expand and cleave the insulating layer, while the insulating layer acts as a heat barrier to prevent heat transfer to the semiconductor substrate, and a protrusion connects the polysilicon layer to the substrate, preventing arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the support substrate is thermally expanded by laser light irradiation to separate it from the insulating layer, then the support substrate and insulating layer can be cleaved, but damage such as lattice defects may occur in the support substrate
Solution Approach 1:
A heat insulating layer is introduced as an intermediary between the support substrate and the semiconductor substrate. This heat insulating layer acts as a mediator that blocks heat transfer from the laser-irradiated support substrate to the semiconductor substrate, preventing thermal damage to the semiconductor substrate while allowing the support substrate to expand and separate from the insulating layer.
Solution Approach 2:
The structure is segmented into distinct functional layers: the support substrate, the heat insulating layer, and the semiconductor substrate. This segmentation allows the support substrate to undergo thermal expansion for separation while the heat insulating layer protects the semiconductor substrate from thermal damage, enabling independent optimization of each layer's function.
2Productivity
If the support substrate is reused after separation, then productivity is improved, but damage from thermal expansion reduces the number of times it can be reused
Solution Approach 1:
The heat insulating layer serves as a protective intermediary that prevents heat from reaching the semiconductor substrate during the separation process. This protection ensures the semiconductor substrate remains undamaged, allowing the support substrate to be separated and reused multiple times without compromising the integrity of the semiconductor substrate, thereby increasing both productivity and substrate durability.
3Manufacturing precision
If laser light is used to thermally expand the support substrate, then separation is achieved, but arcing may occur during the process
Solution Approach 1:
The heat insulating layer acts as an intermediary that not only blocks heat transfer but also serves as a dielectric barrier that prevents arcing during laser irradiation. This intermediate layer isolates the laser field from the semiconductor substrate, eliminating the arcing risk while maintaining the support substrate's ability to expand and separate.
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 allows for the separation of the support substrate without damaging the semiconductor substrate, enabling its reuse and reducing the risk of arcing during manufacturing, thus maintaining device integrity and extending the substrate's lifecycle.
Implementation Method 1
the polysilicon layer absorbs laser light to thermally expand and cleave the insulating layer
Implementation Method 2
the polysilicon layer absorbs laser light to thermally expand and cleave the insulating layer
Implementation Method 3
the insulating layer acts as a heat barrier to prevent heat transfer to the semiconductor substrate
Data Source
AI summary
A stacked substrate according to an embodiment is a stacked substrate for separating using thermal expansion by laser light, and includes: a semiconductor substrate; a first insulating layer disposed above the semiconductor substrate; a first polysilicon layer that is disposed on the first insulating layer in contact with the first insulating layer, and doped with phosphorus; and a second polysilicon layer that extends in the first insulating layer, directly connects the first polysilicon layer and the semiconductor substrate, and is doped with phosphorus.