Semiconductor Trench Formation via Doped Separation Layers
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Solution Overview
Problem
The photolithography process in semiconductor fabrication faces challenges as the critical dimensions approach physical limits, making it difficult to achieve precise pattern transfer and leading to increased process complexity and difficulty in forming semiconductor devices.
Innovation Solution
A method involving the formation of a doped separation layer and separation filling layer in alternating regions of a semiconductor device, which divides trenches into portions, allowing for precise control and reduction of process complexity by independently defining the size of these layers in both directions, thereby overcoming photolithography limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used to transfer pattern from mask to substrate, then pattern transfer is achieved, but manufacturing precision deteriorates as critical dimension approaches physical limits
Solution Approach 1:
The patent applies segmentation by dividing the single photolithography patterning step into multiple sequential steps: forming initial mandrels, depositing first sidewall spacing layer, forming separation trenches, depositing second sidewall spacing layer, and performing final etching. This multi-stage segmentation allows each step to work within achievable dimensional tolerances while the cumulative effect achieves the target critical dimension that would be impossible to achieve in a single photolithography step.
2Manufacturing precision
If dual reconstruction technique is adopted to overcome photolithography limits, then smaller critical dimensions are achieved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating different structural configurations in different regions of the substrate. Separation trenches are formed only in specific regions between adjacent first regions, while mandrels and spacing layers are formed in both first and second regions. This localized differentiation allows the process to achieve complex dual-patterning results while maintaining process control through region-specific structure formation.
3Manufacturing precision
If multiple patterning steps are performed to achieve smaller critical dimensions, then photolithography limits are overcome, but process time increases
Solution Approach 1:
The patent applies preliminary action by pre-forming mandrels with controlled dimensions and positions before the final etching step. The first sidewall spacing layer is deposited and patterned in advance to define separation trench locations. These preliminary structures serve as templates that guide subsequent processing steps, ensuring that the final critical dimensions are achieved without requiring multiple iterative photolithography cycles.
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 formation of semiconductor devices with improved precision and reduced process complexity by allowing for independent control of trench sizes, enhancing the ability to achieve smaller feature sizes and improving the overall fabrication process.
Implementation Method 1
implanting doping ions into the first mask layer formed outside of the trench region of the second region
Data Source
AI summary
A method for fabricating a semiconductor device includes providing a to-be-etched layer, including alternately arranged first regions and second regions along a first direction. Each second region includes a trench region. The method includes forming a first mask layer on the to-be-etched layer; forming a doped separation layer in the first mask layer on the second region of the to-be-etched layer to divide the first mask layer along a second direction perpendicular to the first direction; forming a first trench in the first mask layer on the first region; forming a separation filling layer to divide the first trench along the second direction; implanting doping ions into the first mask layer outside of the trench region; and removing the first mask layer formed in the trench region on both sides of the doped separation layer to form a second trench that is divided into portions along the second direction.