Stress-Transition Films for Substrate Flatness in Photolithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor fabrication processes face challenges in achieving accurate substrate alignment due to substrate bowing and uneven curvature, leading to overlay errors in photolithography, which are difficult to correct using conventional chucking techniques alone.
Innovation Solution
A method of adjusting stress on a substrate by depositing layers of materials with different internal stresses and creating gradual transitions between them using solubility changes and etching processes to form specific slope transitions, allowing for location-specific stress tuning and improved substrate flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chucking techniques are used to correct substrate alignment, then substrate positioning is attempted, but substrate bowing and uneven curvature cause overlay errors that cannot be adequately corrected
Solution Approach 1:
The patent applies preliminary action by depositing stress-tuned films and creating slope transitions before the photolithography process. The stress transitions are pre-engineered into the film structure to proactively compensate for substrate bowing, rather than attempting to correct alignment issues after they occur during exposure
Solution Approach 2:
The patent changes physical parameters by controlling the solubility profiles of deposited films to create specific slope transitions. By adjusting solubility parameters during film deposition, the method creates controlled stress distributions that actively counteract substrate curvature, transforming the substrate surface from non-planar to sufficiently planar for overlay accuracy
2Manufacturing precision
If stress transitions are made abrupt between different stress regions, then manufacturing simplicity is maintained, but substrate warping and overlay errors increase
Solution Approach 1:
The patent applies local quality by creating spatially varying solubility profiles within the film structure. Different regions of the film have different solubility characteristics, allowing the formation of gradual slope transitions in specific locations where stress changes are needed, rather than uniform structures throughout
Solution Approach 2:
The patent transitions from two-dimensional planar film structures to three-dimensional structures with controlled slope transitions. By introducing vertical dimensionality through solubility-based thickness variations, the method creates gradual stress transitions that reduce substrate warping without requiring complex multi-layer configurations
3Manufacturing precision
If multiple thick layers are deposited to compensate for substrate bowing, then substrate flatness can be achieved, but manufacturing time and process complexity increase
Solution Approach 1:
The patent changes the solubility parameter of deposited films to create functional thickness variations without requiring multiple thick physical layers. By controlling solubility during a single or few deposition steps, the method achieves effective stress transition zones that would otherwise require multiple thick layers, thereby maintaining productivity
Solution Approach 2:
The patent creates composite film structures with regions of different solubility characteristics within a single film or minimal layers. This composite approach allows different portions of the film to serve different stress-compensation functions, achieving the effect of multiple specialized layers while using fewer total layers and reducing process steps
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 enables more precise control over substrate stress transitions, reducing overlay errors and improving the accuracy of semiconductor device fabrication by creating a flatter substrate surface with gradual stress transitions, enhancing the alignment of patterns and reducing yield loss.
Implementation Method 1
changing a solubility of the second layer at one or more coordinate locations on the substrate... wherein changing the solubility of the second layer includes creating a transition region defining a predetermined slope of solubility change
Implementation Method 2
removing soluble portions of the second layer using a developer such that remaining portions of the second layer include the predetermined slope
Implementation Method 3
executing an etch process that simultaneously etches the first material and the second material transferring the predetermined slope into the first layer
Implementation Method 4
depositing a first layer of a first material on the substrate; depositing a second layer of a second material on the first layer... the first material has a different internal stress as compared to the second material
Data Source
AI summary
The disclosure relates to a method for tuning stress transitions of films on a substrate. The method includes forming a stress-adjustment layer on the substrate, wherein the stress-adjustment layer includes first regions formed of a first material and second regions formed of a second material, wherein the first material includes a first internal stress and the second material includes a second internal stress, and wherein the first internal stress is different compared to the second internal stress; and forming transition regions between the first regions and the second regions, wherein the transition regions include an interface between the first material and the second material that has a predetermined slope that is greater than zero degrees and less than 90 degrees.