Replacement Contact Etching With Oxide Stop Layer Selectivity
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Solution Overview
Problem
Conventional etch processes face challenges in achieving high selectivity and maintaining critical dimensions in semiconductor devices, particularly with the shrinking sizes of next-generation devices, where standard selectivities are no longer suitable, leading to issues like sidewall losses and over-etching, which affect the formation and spacing of transistor layers.
Innovation Solution
The use of an oxide contact etch stop layer instead of a nitride etch stop layer, combined with a plasma process involving halogen-containing precursors, allows for higher selectivity and precise removal of materials, maintaining the oxide layer and reducing critical dimension loss, enabling improved contact features like wrap-around contacts with multiple sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etch processes are used, then etching can be performed, but selectivity is insufficient leading to sidewall losses and over-etching
Solution Approach 1:
The patent changes the material parameter of the etch stop layer from nitride to oxide, which fundamentally alters the etch selectivity parameters. Oxide provides higher etch selectivity compared to nitride, enabling precise etching without sidewall losses or over-etching. This parameter change resolves the contradiction by improving manufacturing precision while preventing substance loss.
Solution Approach 2:
The oxide etch stop layer acts as an intermediary layer between the contact material and the underlying structure. It mediates the etching process by providing a highly selective stopping point that prevents both sidewall losses and over-etching, thereby resolving the contradiction between achieving sufficient etch selectivity and preventing material loss.
2Manufacturing precision
If standard etch selectivities are used, then etching can be performed, but critical dimension loss occurs in next-generation devices
Solution Approach 1:
The patent changes the etch stop layer material from nitride to oxide, which fundamentally changes the etch selectivity parameters. This parameter change enables precise control of critical dimensions by providing a highly selective etch stop that prevents both insufficient etching and over-etching, thereby resolving the contradiction between maintaining critical dimension control and preventing material loss.
3Adaptability or versatility
If nitride etch stop layer is used, then etching can be performed, but selectivity is insufficient for complex contact geometries
Solution Approach 1:
The patent changes the etch stop layer material parameter from nitride to oxide, which provides superior etch selectivity. This enhanced selectivity enables the formation of complex contact geometries such as wrap-around contacts with multiple sections, resolving the contradiction by improving manufacturing precision while increasing adaptability for complex structures.
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 provides enhanced selectivity and patterning capabilities, limiting sidewall losses and enabling the formation of complex contact geometries with improved metallization and reduced resistance, maintaining additional contact material and maintaining the oxide etch stop layer effectively.
Implementation Method 1
Each of the selective removal operations may be performed using a plasma process including a halogen-containing precursor
Implementation Method 2
The plasma process including a halogen-containing precursor selectively removes silicon material and oxide material through chemical reactions
Data Source
AI summary
Processing methods may be performed to expose a contact region on a semiconductor substrate. The methods may include selectively removing a first region of a silicon material between source/drain regions of a semiconductor substrate to expose a first region of oxide material. The methods may include forming a liner over the first region of oxide material and contacting second regions of the silicon material proximate the source/drain regions of the semiconductor substrate. The methods may also include selectively removing the second regions of the silicon material proximate the source/drain regions of the semiconductor substrate to expose a second region of the oxide material. The methods may further include selectively removing the second region of the oxide material from a surface of a contact in the semiconductor structure.