SiCOH Dielectric Film Porosity Control via Single Precursor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for fabricating SiCOH dielectric materials face challenges such as broad pore size distribution, non-uniform atomic and structural composition, process instability, and thermal instability, which affect the mechanical properties and integration in ultra-large scale integrated (ULSI) circuits.
Innovation Solution
A method using a single organosilicon precursor with a built-in sacrificial organic porogen, where the precursor is deposited and then subjected to an energetic treatment to create a porous SiCOH dielectric film with a dielectric constant of 2.7 or less, achieving uniform and narrow pore size distribution and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional spin-on techniques are used to make SiCOH dielectrics, then the dielectric material can be fabricated, but the final film has a broad pore size distribution including pores larger than 2 nm diameter
Solution Approach 1:
The patent changes the fundamental parameter of pore formation by transitioning from post-deposition porogen removal to in-situ porogen incorporation during deposition. This parameter change enables precise control of pore size distribution at the molecular level, eliminating the broad distribution and large pores characteristic of conventional spin-on techniques.
Solution Approach 2:
The porogen is incorporated into the dielectric film during the deposition process itself, rather than being added and removed in subsequent steps. This preliminary action ensures uniform pore nucleation and growth throughout the film formation, resulting in narrow pore size distribution centered at 1-2 nm.
2Manufacturing precision
If two or more separate organosilicon and/or porogen molecules are used to make SiCOH dielectrics, then the dielectric material can be fabricated, but the film is not uniform in atomic and structural composition across the substrate diameter and through the depth of the dielectric layer
Solution Approach 1:
The patent merges the dielectric matrix functionality and the porogen functionality into a single organosilicon precursor molecule. This consolidation eliminates the complexity of coordinating multiple precursors and ensures uniform atomic and structural composition throughout the film, as both functionalities are delivered in a fixed stoichiometric ratio from one molecular source.
Solution Approach 2:
The single organosilicon precursor molecule performs multiple functions simultaneously: it provides the dielectric matrix structure and incorporates the porogen groups that will form the pores. This multi-functionality simplifies the deposition process and ensures compositional uniformity across the substrate.
3Reliability
If two or more separate organosilicon and/or porogen molecules are used in PECVD process, then the dielectric material can be fabricated, but the process exhibits variation or instability due to drift in the flow rate of one of the two precursors
Solution Approach 1:
By combining the dielectric and porogen functionalities into one precursor molecule, the patent eliminates the need for separate delivery systems for multiple precursors. This single precursor approach removes the source of flow rate drift and process instability that occurs when coordinating the delivery of two or more separate molecules in PECVD processes.
4Manufacturing precision
If two or more separate organosilicon and/or porogen molecules are used in PECVD process, then the dielectric material can be fabricated, but the film has a small component of larger pores due to the formation of dimers or trimers of the porogen in the PECVD reactor
Solution Approach 1:
The porogen groups are pre-positioned within the organosilicon precursor molecule before deposition. This preliminary positioning ensures that porogen groups are distributed uniformly at the molecular level during film formation, preventing the aggregation into dimers or trimers that occurs when separate porogen molecules are delivered and must self-organize in the PECVD reactor.
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 approach results in a SiCOH dielectric film with enhanced mechanical properties, including reduced tensile stress, improved elastic modulus, and hardness, while maintaining a low dielectric constant, suitable for advanced ULSI applications.
Implementation Method 1
a preliminary dielectric film is formed containing at least one organosilicon precursor with the built-in sacrificial organic porogen on a surface of a substrate
Implementation Method 2
an energetic treatment step is performed to substantially remove the built-in sacrificial organic porogen from the preliminary dielectric film
Data Source
AI summary
A method of fabricating a dielectric material that has an ultra low dielectric constant (or ultra low k) using at least one organosilicon precursor is described. The organosilicon precursor employed in the present invention includes a molecule containing both an Si—O structure and a sacrificial organic group, as a leaving group. The use of an organosilicon precursor containing a molecular scale sacrificial leaving group enables control of the pore size at the nanometer scale, control of the compositional and structural uniformity and simplifies the manufacturing process. Moreover, fabrication of a dielectric film from a single precursor enables better control of the final porosity in the film and a narrower pore size distribution resulting in better mechanical properties at the same value of dielectric constant.