Dummy Wafer Protrusions for Thin-Film Thickness Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing demand for semiconductor devices with smaller unit cell areas and pattern widths necessitates reducing film thickness and improving thickness uniformity, while existing dummy wafers face challenges in increasing surface area and maintaining uniformity during thin-film formation processes, leading to variations in film thickness on product wafers.
Innovation Solution
A dummy wafer with an insulating substrate featuring a patterned structure, including openings and protrusions, is used to enhance surface area and uniformity, allowing for improved gas flow and film deposition, and is fabricated at a low cost to facilitate mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the surface area of dummy wafers is increased to improve thickness uniformity, then the thickness uniformity of thin films is improved, but the fabrication cost and complexity increase
Solution Approach 1:
The dummy wafer surface is segmented into multiple protrusions distributed across the surface. These protrusions divide the surface area into multiple smaller active regions, increasing the overall surface area that contributes to uniform gas flow and film deposition without requiring a single large complex structure
Solution Approach 2:
The invention transitions from a flat two-dimensional dummy wafer surface to a three-dimensional surface with protrusions. This dimensional change increases the effective surface area available for interaction with process gases, improving thickness uniformity while maintaining a relatively simple fabrication approach
2Manufacturing precision
If the surface area of dummy wafers is increased to improve thickness uniformity, then the thickness uniformity of thin films is improved, but the fabrication cost increases
Solution Approach 1:
The dummy wafer is fabricated by segmenting the surface into multiple protrusions formed through a multi-step process involving pattern formation, deposition, and etching. This segmented approach allows for cost-effective manufacturing compared to creating a single large complex structure
Solution Approach 2:
The fabrication process utilizes parameter changes in the form of sequential deposition and etching steps to create the protrusion structure. By controlling deposition thickness and etching parameters, the protrusions are formed at low cost using standard semiconductor fabrication equipment
3Productivity
If the film thickness is reduced to meet smaller unit cell area requirements, then the integration density is improved, but the thickness uniformity becomes more difficult to maintain
Solution Approach 1:
The protrusions on the dummy wafer surface create a more uniform gas flow distribution across the wafer surface, establishing equipotential conditions for film deposition. This ensures that even when film thickness is reduced, the deposition conditions remain uniform across the entire surface, maintaining thickness uniformity at thinner film dimensions
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 solution achieves improved thickness uniformity of thin films on product wafers, enhances recycling efficiency of dummy wafers, and reduces fabrication and management costs, thereby improving the reliability and productivity of semiconductor devices.
Implementation Method 1
The first and second surfaces of the insulating substrate, and an inner surface of each of the plurality of openings, may include protrusions
Implementation Method 2
The insulating substrate may include a plurality of openings penetrating at least a portion of the insulating substrate in a direction from the first surface toward the second surface
Data Source
AI summary
Provided are a dummy wafer, a thin-film forming method, and a method of fabricating a semiconductor device using the same. The dummy wafer includes an insulating substrate with a first surface opposite a second surface, and a plurality of openings formed in the insulating substrate. The plurality of openings penetrate at least a portion of the insulating substrate in a direction from the first surface toward the second surface. The first and second surfaces of the insulating substrate, and an inner surface of each of the plurality of openings, include protrusions.