Backside Film Strain Engineering for Substrate Distortion Correction
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Solution Overview
Problem
Semiconductor substrates experience non-uniform localized distortions during chip manufacturing, leading to misalignments in lithography patterns and yield loss, as existing methods for distortion correction either contaminate underlying layers or result in partial relaxation during subsequent processing.
Innovation Solution
A method involving depositing a film on the substrate's backside, followed by annealing, implantation, and etching to create strains that compensate for distortions, using tools like PRODUCER and VIISTA chambers, and a tool with a process chamber for depositing, annealing, and etching film layers, with substrate edge support to manage thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If local implantation of ions is used to correct distortions, then distortion correction is achieved, but contamination of underlying layers occurs
Solution Approach 1:
The patent applies distortion correction by processing the backside of the substrate rather than the front side. By depositing, implanting, and annealing the hardmask layer on the backside, the method creates compensating strains that correct front-side distortions without contaminating the front-side underlying layers. This inversion of the processing location resolves the contamination issue while maintaining distortion correction effectiveness.
2Manufacturing precision
If variable local surface annealing is used to create strains, then distortion compensation is achieved, but partial relaxation occurs during subsequent processing
Solution Approach 1:
The patent performs preliminary strain creation by implanting ions and annealing the hardmask layer on the backside before any front-side processing occurs. This preliminary action establishes the compensating strain pattern early, and subsequent processing steps are designed to maintain rather than relax these strains. The sequence of operations ensures strain stability throughout the manufacturing process.
3Manufacturing precision
If feature sizes are reduced to increase precision, then manufacturing precision improves, but tolerance to distortions decreases
Solution Approach 1:
The patent applies preliminary anti-action by creating compensating strains on the backside of the substrate before front-side lithography and patterning. These pre-applied strains counteract the distortions that would otherwise affect the alignment of lithography patterns. By establishing this compensating strain pattern in advance, the method enables precise lithography at reduced feature sizes while maintaining tolerance to distortions through the compensating effect.
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 distortions on the substrate's front side by creating desired stress patterns on the backside, reducing yield loss and maintaining the integrity of underlying layers, while allowing for precise alignment and patterning.
Implementation Method 1
annealing the substrate... thermally treating the backside of the substrate... to counteract thermal stresses
Implementation Method 2
implanting on the backside of the substrate... The local strains compensate the previously existing ones
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. In some embodiments, localized strains may be introduced by locally altering the hydrogen content of a silicon nitride film or a carbon film, among other techniques. 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.