Epitaxial Alignment Structure Imaging for Semiconductor Lithography
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Solution Overview
Problem
The complexity of aligning device patterns in successively grown epitaxial layers with respect to an alignment structure in semiconductor device manufacturing is high, requiring intricate mask alignment and multiple lithography processes, which increases process complexity and costs.
Innovation Solution
A method involving the formation of an initial mask with openings exposing alignment and super-junction structure areas, followed by creating a recess structure and introducing dopants, where the initial alignment structure is imaged into the semiconductor layer, allowing subsequent epitaxial growth and dopant introduction using aligned masks to simplify the alignment process and reduce lithography complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional alignment methods using separate masks for alignment structures and device patterns are used, then alignment precision is maintained, but device complexity and lithography process complexity increase
Solution Approach 1:
The patent combines the formation of alignment structures and device patterns into a single lithography step using one mask. The mask includes both alignment structure openings and device pattern openings, allowing simultaneous exposure and formation of both features. This merging eliminates the need for separate alignment mask and device pattern mask steps, reducing lithography process complexity while maintaining alignment precision through the integrated design.
Solution Approach 2:
The single mask serves multiple functions: it defines alignment structures for subsequent lithography alignment and simultaneously defines device patterns for device formation. This multi-functional mask replaces the conventional separate masks, simplifying the overall lithography process while maintaining the ability to achieve precise alignment in subsequent processing steps.
2Manufacturing precision
If multiple separate lithography processes are used for alignment structures and device patterns, then alignment accuracy is achieved, but manufacturing time and process steps increase
Solution Approach 1:
The patent merges multiple lithography processes into a single exposure step. By incorporating both alignment structure openings and device pattern openings in one mask, the simultaneous exposure process eliminates sequential processing steps, reducing total manufacturing time and improving productivity while maintaining alignment accuracy through the integrated mask design.
Solution Approach 2:
The alignment structures are formed preliminarily in the same lithography step as device patterns, creating reference features that guide subsequent alignment operations. This preliminary formation of alignment structures within the single exposure step enables accurate alignment in later processing without requiring additional lithography cycles.
3Manufacturing precision
If conventional separate mask alignment methods are used, then device pattern alignment is achieved, but process costs increase
Solution Approach 1:
The patent combines the formation of alignment structures and device patterns into a single lithography process using one mask, eliminating the need for multiple separate masks and processing steps. This reduction in the number of components and process steps directly lowers manufacturing costs while maintaining device pattern alignment precision through the integrated mask design.
Solution Approach 2:
The single mask performs multiple functions simultaneously: creating alignment structures for future alignment operations and defining device patterns for device fabrication. This multi-functionality eliminates the need for separate specialized masks, reducing material costs and process complexity while achieving the required alignment precision.
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 simplifies the alignment process, reduces lithography complexity, and lowers costs by using a common mask for forming alignment structures and device patterns in both the kerf and device areas, enabling efficient semiconductor device manufacturing.
Implementation Method 1
increasing a thickness of the semiconductor layer by growing an epitaxial layer, wherein the initial alignment structure is imaged into the process surface
Data Source
AI summary
A semiconductor device is manufactured in a semiconductor body by forming an initial mask on a process surface of a semiconductor layer, openings in the mask exposing a part of the semiconductor layer in alignment structure and super-junction structure areas. A recess structure is formed in the semiconductor layer at portions of the process surface that are exposed by the openings, the recess structure in the alignment structure area constituting an initial alignment structure. Dopants are introduced into the semiconductor layer through portions of the process surface that are exposed by the openings of the initial mask. The dopants introduced in the super-junction area constitute part of a super-junction structure. A thickness of the semiconductor layer is increased by growing an epitaxial layer. The initial alignment structure is imaged into the process surface. Dopants are introduced into the semiconductor layer by using a mask aligned to the initial alignment structure.