Asymmetric Rhomboid Mask Patterning for Semiconductor Landing Pad Reliability
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Solution Overview
Problem
As the integration of semiconductor devices increases, the reliability of the devices is compromised due to electrical shorts between landing pads, which is exacerbated by the reduced process margin in forming these pads.
Innovation Solution
A method involving the formation of rhomboid-shaped mask patterns with adjusted diagonal lengths, followed by a trimming process to create masks with a greater first diagonal length than second diagonal length, is used to pattern the semiconductor device, preventing electrical shorts by adjusting the aspect ratio of the masks and target patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the degree of integration of the semiconductor device is increased, then the productivity and device density are improved, but the process margin for forming landing pads is reduced and reliability deteriorates
Solution Approach 1:
The mask pattern is designed with an asymmetric rhomboid shape where the first diagonal length is greater than the second diagonal length. This asymmetry creates different etching rates at different portions of the mask, allowing precise control of the landing pad dimensions to prevent electrical shorts while maintaining high integration density
Solution Approach 2:
Different portions of the mask pattern are given different properties through the asymmetric rhomboid design. The first portions (corresponding to first opposite vertices) are etched more than the second portions (corresponding to second opposite vertices), creating local variations in the mask thickness that control the landing pad formation process to prevent electrical shorts
2Ease of manufacture
If a conventional mask patterning process is used, then the manufacturing process is simple, but the landing pads are formed with reduced process margin leading to electrical shorts
Solution Approach 1:
The mask pattern geometry is changed from a conventional symmetric shape to an asymmetric rhomboid shape with specific diagonal length ratios. This parameter change in the mask design enables precise control of the etching process to form landing pads with appropriate dimensions and spacing, preventing electrical shorts while maintaining manufacturing feasibility
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 approach enhances the reliability of semiconductor devices by preventing electrical shorts between landing pads, ensuring proper patterning and reducing the risk of device failure.
Implementation Method 1
A trimming process is performed on the second mask patterns to form second masks. First portions corresponding to first opposite vertices of each of the second mask patterns are etched more than second portions corresponding to second opposite vertices of each of the second mask patterns.
Implementation Method 2
The first mask layer is patterned to form first masks by performing an etching process on the first mask layer using the second masks as an etching mask. The target layer is patterned to form target patterns by performing an etching process on the target layer using the first masks as an etching mask.
Data Source
AI summary
First and second mask layers are formed on a target layer. The second mask layer is patterned to form second mask patterns each of which having a rhomboid shape with a first diagonal length and a second diagonal length. A trimming process is performed on the second mask patterns to form second masks by etch. First portions of first opposite vertices of each second mask pattern are etched more than second portions of second opposite vertices of each second mask pattern. A first diagonal length between the first opposite vertices is greater than a second diagonal length between the second opposite vertices. The first mask layer is patterned to form first masks by etching the first mask layer using the second masks as an etching mask. The target layer is patterned to form target patterns by etching the target layer using the first masks as an etching mask.