Multi-Layer Mask Structure for Deep Small-Diameter Hole Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching technologies face limitations in forming through-holes with small diameters and large depths due to the thickness constraints of photoresist masks, which are insufficient for precise 3D integrated circuit manufacturing.
Innovation Solution
A pattern sheet with a multi-layer mask structure is used, where each layer's thickness and etching selectivity ratios are optimized to ensure that each layer can act as a mask for the next, allowing for the formation of through-holes with greater depths in substrates and dielectric layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photoresist mask is used for etching through-holes with small diameter and large depth, then the mask opening size can be reduced, but the mask thickness is limited by photolithography exposure energy and accuracy
Solution Approach 1:
The mask structure is divided into multiple layers: a first mask layer (photoresist) formed by photolithography, and a second mask layer (such as silicon oxide or silicon nitride) deposited on top. This segmentation allows the photoresist layer to define the pattern with high precision while the second mask layer provides the necessary thickness for deep hole etching, resolving the contradiction between mask opening size and mask thickness.
Solution Approach 2:
The patent uses a composite mask structure combining different materials with complementary properties. The photoresist material provides good lithographic properties for precise pattern formation, while the deposited material (such as silicon oxide or silicon nitride) provides sufficient thickness and etching resistance. This composite approach allows the mask to simultaneously achieve both small opening size and large thickness.
2Length of stationary object
If the photoresist mask thickness is increased to etch deeper holes, then the hole depth capability improves, but the exposure energy and accuracy requirements cannot be met
Solution Approach 1:
The mask is segmented into a thin first mask layer for precise pattern definition and a thick second mask layer for sufficient etching depth. The first mask layer maintains thinness for good lithographic resolution, while the second mask layer compensates for the limited thickness, enabling deep hole etching without compromising pattern precision.
Solution Approach 2:
The second mask layer acts as an intermediary between the photoresist pattern and the etching process. It receives the pattern from the photoresist layer and provides the additional thickness needed for deep etching, mediating between the conflicting requirements of pattern precision and etching depth capability.
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
The present disclosure discloses a pattern sheet, a semiconductor intermediate product, and a hole etching method. The pattern sheet includes a substrate, a dielectric layer, and a mask structure. The mask structure includes a multi-layer mask layer. An uppermost mask layer is a photoresist layer. A thickness of each layer of the mask layer and etching selectivity ratios between the layers below the mask layer satisfy that in each two neighboring layers of the mask layer, a lower layer of the mask layer is etched to form a through-hole penetrating a thickness of the lower layer of the mask layer, a remaining thickness of the upper layer of the mask layer is greater than or equal to zero. While the dielectric layer is etched to form a through-hole penetrating a thickness of the dielectric layer, a remaining thickness of all the mask layer above the dielectric layer is greater than zero. While the hole with the set depth is formed in the substrate, the remaining thicknesses of all the mask layer above the dielectric layer is greater than or equal to zero. By using the above technical solution, a hole with a larger depth can be formed in the substrate to meet the application requirements.