Imprint Template With Varying Step Heights For Semiconductor Staircase Structures
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Solution Overview
Problem
Conventional semiconductor manufacturing methods face challenges in efficiently forming staircase structures with precise height control and minimizing step shifts during the etching process, which affects the throughput and cost-effectiveness of semiconductor device production.
Innovation Solution
The use of a template with a staircase pattern of varying step heights in the imprint lithography process allows for the formation of a three-dimensional structure in a single transfer operation, enabling precise etching and reducing the occurrence of step shifts by adjusting the height ratio of steps in the template and subsequent etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photolithography is used, then manufacturing precision can be maintained, but productivity decreases and costs increase due to multiple transfer operations required for staircase structures
Solution Approach 1:
The patent combines multiple etching steps into a single imprint lithography operation by using a template with varying step heights that correspond to different etching depths. This allows the formation of complete staircase structures in one transfer operation, eliminating the need for multiple sequential photolithography steps and thereby improving productivity while maintaining precision.
Solution Approach 2:
The patent introduces height variation in the template steps as an additional dimension to encode etching depth information. By varying the step heights in the template, different etching depths are achieved in a single operation, transforming a multi-step process into a single-step process that improves throughput without sacrificing structural precision.
2Manufacturing precision
If multiple transfer operations are used to form staircase structures, then manufacturing precision can be maintained, but loss of time increases due to repeated processing steps
Solution Approach 1:
The patent performs preliminary action by pre-configuring the template with varying step heights that correspond to the desired staircase structure. This preliminary design of the template allows all etching depth information to be encoded in advance, enabling a single transfer operation to achieve what would otherwise require multiple sequential operations, thereby reducing processing time while maintaining precision.
3Manufacturing precision
If standard etching processes are used with uniform step templates, then process simplicity is maintained, but manufacturing precision deteriorates due to step shifts during etching
Solution Approach 1:
The patent applies local quality by varying the step heights at different locations in the template according to the specific etching depth requirements. Each step's height is locally optimized to achieve the desired etching depth for that region, preventing step shifts and improving alignment precision. This localized variation in step heights allows the template to compensate for potential alignment issues during the etching process.
4Productivity
If imprint lithography with varying step heights is used, then productivity increases through single-transfer operation, but device complexity increases due to template design requirements
Solution Approach 1:
The patent uses parameter changes by varying the height parameter of the template steps to encode different etching depth information. This systematic variation of the step height parameter allows a single template to control multiple etching depths, achieving high productivity through single-transfer operation. The parameter changes in the template design are directly translated into the desired staircase structure in the final product.
Data Source
AI summary
According to an embodiment, a template includes steps in first to Nth (N is an integer of 2 or greater) stairs formed in a staircase pattern in a height direction. The steps include first steps in the first to Kth (K is an integer of 1 or greater and N−1 or less) stairs and second steps in (K+1)th to Mth (M is an integer of K+1 or greater and N or less) stairs. A height of the second steps is greater than a height of the first steps.