MIM Capacitor Structure Using Self-Aligned Spacers to Cut Photomasks
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Solution Overview
Problem
The fabrication of capacitors in integrated chips is costly due to the need for multiple photomasks in patterning processes, leading to increased production costs and potential electrical shorts.
Innovation Solution
The use of self-aligned spacers in the fabrication process reduces the number of photomasks required by using them as masks to pattern electrode and dielectric layers, thereby lowering costs and preventing electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photomasks are used in patterning processes, then precise patterning of electrode and dielectric layers can be achieved, but fabrication costs increase and production complexity increases
Solution Approach 1:
The spacer structures serve as self-aligned masks that automatically define the patterning locations for subsequent etching steps. The spacers are formed by depositing material conformally on existing structures and then performing anisotropic etching, which creates the mask patterns without requiring external photomask alignment. This self-service approach eliminates the need for multiple photomasks while maintaining precise patterning control.
Solution Approach 2:
The spacer structures are formed in advance before the actual electrode and dielectric layer patterning. These pre-formed spacers act as templates that guide subsequent etching processes, ensuring that all patterning steps are automatically aligned to the correct locations. This preliminary action of creating alignment references eliminates the need for multiple photomasks and their associated alignment procedures.
2Manufacturing precision
If multiple photomasks are used in patterning processes, then complete coverage of all layers can be achieved, but the number of fabrication steps increases
Solution Approach 1:
The spacer structures serve multiple functions simultaneously: they act as etch masks for defining electrode patterns, serve as alignment references for subsequent dielectric layer patterning, and provide physical barriers to prevent material deposition in unwanted areas. This multi-functionality allows a single spacer formation process to replace what would traditionally require multiple separate photomasking and patterning steps.
Solution Approach 2:
The invention combines the mask formation and alignment reference creation into a single spacer deposition and etching process. Instead of using separate photomasks for each layer patterning step, the spacers are formed once and then used as universal masks for all subsequent patterning operations, merging multiple process steps into a more integrated sequence.
3Ease of manufacture
If traditional patterning processes are used, then standard fabrication procedures can be followed, but electrical shorts may occur between adjacent structures
Solution Approach 1:
The spacer structures are formed in advance to create physical barriers and define precise boundaries between adjacent electrode and dielectric structures. By establishing these isolation regions before subsequent material depositions, the process prevents potential electrical shorts from occurring in the first place, rather than attempting to correct them later.
Solution Approach 2:
The spacer structures serve as intermediary elements between adjacent functional structures. These spacers act as buffer zones that physically separate electrodes and dielectric layers, preventing direct contact that could cause electrical shorts. The spacers mediate the spatial relationship between neighboring structures, ensuring proper electrical isolation while maintaining compact device layout.
Data Source
AI summary
A capacitor structure and a method for fabricating the capacitor are provided. The method includes forming a stack of a first electrode layer, a first dielectric layer, a second electrode layer, a second dielectric layer and a third electrode layer; forming a first spacer on the second dielectric layer and patterning the second dielectric layer and the second electrode layer by using the first spacer as a mask; forming a second spacer on the first dielectric layer and patterning the first dielectric layer and the first electrode layer by using the first spacer and the second spacer as a mask; and forming a first conductive layer on the first spacer and the second spacer to electrically connect the third electrode layer and the first electrode layer.