Phase Change Memory Spacer Patterning for Edge Leaning Prevention
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Solution Overview
Problem
The existing methods for forming a cell array of a phase change semiconductor device often result in the leaning of phase change structures at the outermost patterning parts during the patterning process, leading to potential damage and defects due to uneven etching effects.
Innovation Solution
The method involves forming a first sacrificial film and a partition mask with non-uniform line-shaped spaces, where the outermost spaces are narrower than the inner spaces, and using spacer patterning technology to create spacers that contact or are close to each other, thereby forming protective patterns with increased width at the outermost edges to prevent leaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional uniform partition mask is used for patterning, then manufacturing process is simple, but outermost phase change structures lean and get damaged during etching
Solution Approach 1:
The partition mask is designed with asymmetric space widths where outermost spaces are narrower than inner spaces. This asymmetric configuration compensates for the leaning of outermost phase change structures during etching, ensuring that the narrower outermost spaces provide sufficient support to prevent damage while maintaining overall pattern integrity.
Solution Approach 2:
Different regions of the partition mask are assigned different space widths according to their specific needs. The outermost regions have narrower spaces to prevent leaning, while inner regions have wider spaces. This local differentiation optimizes the protective effect precisely where needed without unnecessarily complicating the entire mask design.
2Reliability
If outermost spaces are made narrower to prevent leaning, then structural integrity improves, but manufacturing precision requirements increase
Solution Approach 1:
The partition mask is designed in advance with predetermined non-uniform space widths that account for expected leaning during the subsequent etching process. By pre-compensating for the leaning effect through carefully calculated narrower outermost spaces, the design ensures structural integrity without requiring real-time adjustments during manufacturing.
Data Source
AI summary
A method for forming a semiconductor device is disclosed. The method for forming the semiconductor device includes forming a first sacrificial film over a target layer to be etched, forming a first partition mask over the first sacrificial film, forming a first sacrificial film pattern by etching the first sacrificial film using the first partition mask, forming a first spacer at a sidewall of the first sacrificial film pattern, and forming a first spacer pattern by removing the first sacrificial film pattern. The first partition mask includes a plurality of first line-shaped space patterns extending in a first direction. A width of at least one space pattern located at both edges from among the plurality of first space patterns is smaller than a width of each of other space patterns.