Via Opening Etching with High Polymer Gas
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Solution Overview
Problem
In semiconductor manufacturing, the miniaturization of IC devices leads to overlay errors and un-landed phenomena during dielectric layer etching, resulting in misalignment and exposure of conductive layers, which causes residue formation and affects electrical quality.
Innovation Solution
A method involving a first dry etching step with a high polymer gas to form an opening with an obtuse angle, followed by a second dry etching step to enlarge the opening to a target dimension, preventing conductive layer exposure and residue formation, while controlling etching depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional etching process is used to form via openings, then the etching depth can be achieved, but un-landed phenomenon occurs and conductive layers are exposed due to overlay errors and misalignment
Solution Approach 1:
The method performs a preliminary etching step to form an opening that stops before exposing the conductive layer, then performs a second etching step to complete the via opening. This preliminary action prevents the un-landed phenomenon by ensuring the opening is properly formed in the dielectric layer before reaching the conductive layer.
Solution Approach 2:
The etching process is divided into multiple steps: first etching the dielectric layer to form an opening, then etching through the conductive layer to form the via opening. This segmentation allows precise control over when the conductive layer is exposed, preventing premature exposure due to overlay errors.
2Productivity
If etching is performed through the dielectric and passivation layers, then via openings are formed, but residues such as fluorine aluminum remain and cannot be completely removed
Solution Approach 1:
The method uses a specific etching chemistry that produces volatile residues which can be easily removed, converting the harmful non-volatile residues into beneficial volatile products. The etching process is designed to produce residues that evaporate during subsequent processing, eliminating the contamination problem.
Solution Approach 2:
The etching process parameters are optimized to control the chemical reactions during etching, ensuring that the residues produced are volatile and can be removed. By adjusting etching conditions, the method transforms the residue composition from harmful non-volatile substances to beneficial volatile substances.
3Manufacturing precision
If the opening is enlarged to reach target dimension, then the via opening is complete, but the conductive layer may be exposed causing un-landed phenomenon
Solution Approach 1:
The method first forms an opening in the dielectric layer with controlled dimensions, then enlarges it to the target dimension while monitoring to prevent conductive layer exposure. This preliminary formation ensures the opening is properly positioned before enlargement, preventing un-landed phenomenon.
Solution Approach 2:
The etching process includes feedback control to monitor the opening formation and adjust etching parameters to prevent over-etching that would expose the conductive layer. The process responds to real-time conditions to maintain precise dimensional control while protecting the conductive layer.
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 method ensures precise control of opening dimensions, avoids un-landed phenomena, and enhances electrical performance by preventing residue formation, thereby improving the quality of via plugs and overall device efficiency.
Implementation Method 1
A first dry etching step is then performed to form an opening on the passivation layer by using a reactive gas containing a high polymer gas
Data Source
AI summary
A method of manufacturing an opening is described. First, a substrate including a conductive portion and a dielectric layer both formed thereon is provided. The conductive portion at least includes a conductive layer and a passivation layer from bottom-up, and the dielectric layer covers the conductive portion. A first dry etching step is then performed to form an opening on the passivation layer by using a reactive gas containing a high polymer gas. The bottom of the opening has an initial dimension, and an obtuse angle is included by the bottom of the opening and an inner sidewall of the opening. Next, an opening enlarging step is performed to reach a target dimension of the bottom of the opening. The target dimension is larger than the initial dimension and to the least extent the conductive layer is not exposed by the opening.