Spin-On Hard Mask Stack for Thermal Stress and Etch Selectivity
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Solution Overview
Problem
Semiconductor devices face challenges with hard mask structures formed through chemical vapor deposition (CVD), including defects and the need for independent equipment due to vacuum processing, and existing spin-on hard (SOH) masks may not adequately address thermal stress and etch selectivity issues.
Innovation Solution
A semiconductor device with a hard mask structure comprising a stack of layers including a first and second SOH layers, one containing carbon, hydrogen, oxygen, and nitrogen, and the other containing carbon and oxygen, which helps in reducing thermal stress and enhancing etch selectivity by allowing organic byproducts to escape, thereby improving the structural integrity and processing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a hard mask is formed through chemical vapor deposition (CVD), then the hard mask can be formed with good film quality, but particles are formed causing defects and independent equipment is needed due to vacuum processing
Solution Approach 1:
The patent replaces the CVD process (which operates in vacuum and forms particles) with a spin coating process. The spin-on hard mask is applied by spinning the substrate to evenly distribute the mask material, eliminating the need for vacuum equipment and avoiding particle formation associated with CVD processes.
2Device complexity
If a single SOH layer is used, then the process is simple, but thermal stress causes destruction and etch selectivity is insufficient
Solution Approach 1:
The patent divides the hard mask structure into multiple layers: a first SOH layer and a second SOH layer with different compositions. The first layer contains C, H, O, and N, while the second layer contains C, H, and O. This segmentation allows each layer to contribute differently to thermal stress management and etch selectivity, improving overall reliability.
Solution Approach 2:
The patent uses composite material composition in the multi-layer SOH structure, where each layer has a distinct chemical composition (differentiating by presence/absence of nitrogen and other elements). This composite approach enables tailored properties for thermal stress resistance and etch selectivity that cannot be achieved with a single uniform material.
3Stability of the object's composition
If organic byproducts are trapped in the hard mask, then the structure remains intact, but stress accumulates leading to destruction
Solution Approach 1:
The patent incorporates porous structures within the SOH layers, creating pathways for organic byproducts to escape during processing. The porous morphology allows gases to vent through the mask structure rather than becoming trapped, preventing stress accumulation and subsequent destruction while maintaining structural integrity.
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
The proposed hard mask structure effectively reduces the likelihood of destruction due to thermal stress and achieves higher etch selectivity, enhancing the reliability and performance of semiconductor devices.
Implementation Method 1
a first organic layer including a spin on hard mask (hereinafter referred to as an SOH) containing carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), and the other one of the first hard mask layer and the second hard mask layer includes a second organic layer including an SOH containing C, H, and O
Data Source
AI summary
Provided is a semiconductor device. The semiconductor device includes a wafer; an etch stop layer on the wafer; a lower mold layer on the etch stop layer; an intermediate supporter layer on the lower mold layer; an upper mold layer on the intermediate supporter layer; an upper supporter layer on the upper mold layer; and a hard mask structure on the upper supporter layer, wherein the hard mask structure includes a first hard mask layer on the upper supporter layer and a second hard mask layer on the first hard mask layer, one of the first hard mask layer and the second hard mask layer includes a first organic layer including a SOH containing C, H, O, and N, and the other one of the first hard mask layer and the second hard mask layer includes a second organic layer including an SOH containing C, H, and O.