FinFET Fin Height Control via Selective Etch Stop Layer
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Solution Overview
Problem
The existing methods for manufacturing FinFETs lack precise control over the height of the fin, leading to indirect and inaccurate control of the channel width in the final device.
Innovation Solution
The use of two semiconductor layers with etching selectivity allows for the precise patterning of a fin, where one layer serves as a stop layer, enabling direct control over the fin height and subsequently the channel width by determining the height of the semiconductor material layer constituting the fin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single-layer patterning method is used to form fin, then manufacturing process is simple, but fin height control is inaccurate
Solution Approach 1:
The semiconductor layer is divided into two distinct layers: a first semiconductor layer (fin formation layer) and a second semiconductor layer (stop layer). This segmentation allows the fin height to be precisely controlled by the thickness of the first layer, while the second layer provides a defined etch stop, resolving the contradiction between manufacturing precision and process complexity.
Solution Approach 2:
The two semiconductor layers are formed in advance with predetermined thicknesses and material compositions before the etching process. The etch selectivity between the layers is established beforehand, enabling accurate fin height control during subsequent patterning without requiring complex real-time adjustments.
2Manufacturing precision
If etching process parameters are adjusted to control fin height, then channel width can be controlled indirectly, but control accuracy is insufficient
Solution Approach 1:
The second semiconductor layer acts as an intermediary etch stop layer between the fin structure and the substrate. By controlling the etch selectivity between the first and second layers, the fin height is determined by the first layer's thickness rather than by adjusting etching parameters, thereby improving both control accuracy and measurement precision.
Solution Approach 2:
The invention changes the material composition parameters of the semiconductor layers to create etch selectivity. The first layer has different etch resistance compared to the second layer, allowing precise control of fin height through material parameter selection rather than process parameter adjustment.
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 allows for accurate control of the fin height and channel width, enhancing the manufacturing process by ensuring reliable heat dissipation and precise electrical control.
Implementation Method 1
a first semiconductor layer and a second semiconductor layer on the substrate, wherein the first semiconductor layer and the second semiconductor layer comprise different materials and have etching selectivity with respect to each other
Data Source
AI summary
Semiconductor devices and methods for manufacturing the semiconductor devices are disclosed. A semiconductor device includes a substrate, a fin formed above the substrate with a semiconductor layer formed between the substrate and the fin, and a gate stack crossing over the fin. The fin and the semiconductor layer may include different materials and have etching selectivity with respect to each other. A patterning of the fin can be stopped reliably on the semiconductor layer. Therefore, it is possible to better control the height of the fin and thus the channel width of the final device.