Backside Substrate Film Strain Compensation
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Solution Overview
Problem
During semiconductor chip manufacturing, substrates experience non-uniform localized distortions that cannot be corrected, leading to yield loss as feature sizes shrink, and existing methods like ion implantation and surface annealing are either contaminated or result in partial relaxation of strains.
Innovation Solution
A method involving depositing films on the backside of the substrate, followed by annealing and implantation to introduce strains that compensate for distortions on the top surface, using tools like PRODUCER and VIISTA chambers for precise control of film deposition and stress adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion implantation is used to correct distortions, then local strains are created to compensate for existing distortions, but contamination of the underlying layers occurs
Solution Approach 1:
Instead of implanting ions into the front side hardmask to create strains, the patent applies strain to the backside of the substrate. This inverted approach achieves distortion correction without contaminating the front side layers, as the strain is applied from the opposite side where it cannot cause contamination issues.
Solution Approach 2:
The patent introduces a backside film as an intermediary medium to apply strain to the substrate. This film serves as a mediator that transfers strain to the substrate without requiring direct ion implantation into the sensitive front side layers, thus avoiding contamination while still achieving the desired strain effect.
2Manufacturing precision
If variable local surface annealing is used to correct distortions, then local strains are created to compensate for existing ones, but partial relaxation occurs as the surface is removed during subsequent processing
Solution Approach 1:
Instead of annealing the front side surface to create strains, the patent applies strain to the backside of the substrate. This inverted approach ensures that the strain is not lost during front side processing steps, as the strain source is located on the opposite side and protected from removal or relaxation during subsequent front side processing.
Solution Approach 2:
The patent applies strain to the backside before any front side processing occurs. This preliminary strain application ensures that the strain is established and maintained throughout subsequent processing steps, preventing the partial relaxation that occurs when strain is applied to the surface and then the surface is removed or modified.
3Manufacturing precision
If feature sizes continue to shrink, then manufacturing precision requirements increase, but the number of uncorrectable distortions increases
Solution Approach 1:
The patent applies strain to the backside of the substrate rather than the front side, creating a more effective distortion correction mechanism. This inverted approach provides better control over substrate flatness and alignment, which is critical as feature sizes shrink and tolerance requirements become more stringent, thereby improving yield.
Solution Approach 2:
The patent changes the parameter of strain application location from front side to backside, and controls the magnitude and distribution of strain through film deposition and annealing parameters. This allows precise adjustment of substrate flatness to meet the increasingly tight alignment tolerances required as feature sizes shrink, improving both manufacturing precision and yield.
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 effectively compensates for undesirable strains on the top surface of the substrate by creating controlled stress patterns on the backside, improving alignment and reducing yield loss by maintaining consistent strain consistency and avoiding contamination or partial relaxation.
Implementation Method 1
depositing a film on the backside of the substrate
Implementation Method 2
annealing the substrate
Implementation Method 3
annealing the plurality of film layers on the backside of the substrate
Implementation Method 4
implanting on the backside of the substrate
Implementation Method 5
etching the backside of the substrate
Data Source
AI summary
Embodiments disclosed herein generally relate to methods and apparatus for processing of the bottom surface of a substrate to counteract thermal stresses thereon. Correcting strains are applied to the bottom surface of the substrate which compensate for undesirable strains and distortions on the top surface of the substrate. Specifically designed films may be formed on the back side of the substrate by any combination of deposition, implant, thermal treatment, and etching to create strains that compensate for unwanted distortions of the substrate. Localized strains may be introduced by locally altering the hydrogen content of a silicon nitride film or a carbon film. Structures may be formed by printing, lithography, or self-assembly techniques. Treatment of the layers of film is determined by the stress map desired and includes annealing, implanting, melting, or other thermal treatments.