Semiconductor Plug Hole Patterning via Self-Aligned Spacer
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Solution Overview
Problem
Conventional methods for forming plug holes in semiconductor devices are costly and inefficient, requiring repetitive steps for each hole and resulting in varying pitches between adjacent holes due to the use of patterned photoresist masks, which complicates the alignment of conductive and contact plugs.
Innovation Solution
A method involving the formation of a multi-layer film with alternating conductive and dielectric layers, where a patterned dielectric layer with specific hole configurations allows for simultaneous etching of multiple plug holes using polymer and photoresist layers, ensuring consistent pitch and precise alignment of contact plugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods form plug holes one at a time using patterned photoresist masks, then each plug hole can be precisely formed, but the manufacturing cost increases and the process time extends
Solution Approach 1:
The patent combines multiple plug hole formation operations into a single etching process. Multiple plugs are formed simultaneously by defining their positions through a self-aligned spacer structure rather than requiring separate photoresist masks for each plug, thereby improving productivity while maintaining precision through the self-alignment mechanism
Solution Approach 2:
The method performs preliminary actions by first forming the conductive plugs and their spacers before forming the contact holes. This preliminary establishment of the plug structure with spacers provides self-alignment references for subsequent contact hole formation, ensuring precision without requiring additional alignment steps
2Ease of manufacture
If patterned photoresist masks are used for each plug hole, then plug holes can be formed at specific locations, but the pitches between adjacent plug holes vary
Solution Approach 1:
The spacer structure serves itself as the alignment reference for forming contact holes. The spacer width directly determines the pitch between contact holes, eliminating pitch variations that would otherwise result from separate photoresist patterning steps. The structure defines its own positions through the self-aligned spacer formation process
Solution Approach 2:
Instead of using photoresist masks to define plug hole positions directly, the invention inverts the approach by first forming conductive plugs, then using spacers formed on these plugs to define the positions of subsequent contact holes. This inversion ensures pitch consistency because the spacer width, not photoresist alignment, determines the pitch
3Manufacturing precision
If conductive plugs and contact plugs require tight overlay specification, then precise alignment is achieved, but the manufacturing complexity increases
Solution Approach 1:
The spacer structure acts as an intermediary between the conductive plugs and the contact holes. It provides a self-aligned reference that automatically ensures precise overlay without requiring complex alignment processes. The spacer serves as the mediating element that transfers the position information from the conductive plugs to the contact hole formation process
Solution Approach 2:
The spacer structure provides self-alignment for contact hole formation. The contact holes are formed using the spacer as the alignment reference, eliminating the need for separate overlay alignment steps. This self-service mechanism reduces manufacturing complexity while maintaining tight overlay specifications
Data Source
AI summary
A method for patterning a multi-layer film in a semiconductor device is provided. The semiconductor device comprises a substrate and a multi-layer film on the substrate. The multi-layer film comprises N conductive layers and N dielectric layers alternatingly stacked, and 2N contact plugs. The Nth dielectric layer is formed at the top of the multi-layer film. The distances between the centers of each adjacent contact plugs are the same.