Semiconductor Wafer Backside Recess With Side-Flat Orientation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wafer processing methods face challenges in forming a notch or orientation flat that requires a projection width equal to or larger than the notch width, limiting the formation of larger recess areas for increased device capacity.
Innovation Solution
A method involving grinding the back surface of a semiconductor wafer to form a recess and a surrounding projection, and an ingot processing method that includes detecting crystal orientation to form a linear flat mirror surface portion and separate wafers, allowing for the formation of a projection that functions as a reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a notch or orientation flat is formed on the wafer to indicate crystal orientation, then the crystal orientation can be identified, but the projection width must be equal to or larger than the notch width which limits the recess area
Solution Approach 1:
The patent extracts the crystal orientation indication function from the traditional notch structure and relocates it to the side surface of the wafer. By forming a flat surface on the side surface that corresponds to a crystal plane, the orientation information is obtained without requiring a large projection on the top surface, thus enabling larger recess areas while maintaining orientation identification capability.
Solution Approach 2:
The patent moves the orientation indication from the two-dimensional top surface (notch) to the three-dimensional side surface (flat surface). This dimensional transition allows the orientation information to be accessed from the side rather than requiring a large area on the top surface, resolving the contradiction between orientation indication and recess area.
2Productivity
If a large recess area is formed to increase device capacity, then more devices can be formed, but the wafer strength during grinding is reduced
Solution Approach 1:
The patent performs preliminary reinforcement by forming a projection around the recess area before the actual recess formation. This projection acts as a structural support that maintains wafer strength during the grinding process, enabling the subsequent formation of large recess areas without compromising wafer integrity during manufacturing.
Solution Approach 2:
The patent applies local reinforcement by creating a projection specifically at the boundary region around the recess. This localized structural enhancement provides strength where it is most needed (at the edges of the large recess area) while allowing the center region to be maximally recessed for device formation.
3Area of moving object
If the projection width is increased to maintain wafer strength, then the recess area is reduced, but if the projection width is decreased to increase recess area, then the projection cannot function as effective reinforcement
Solution Approach 1:
The patent enhances the projection's reinforcement function by extending it in the vertical dimension (depth) rather than relying solely on horizontal width. The projection has a controlled depth that provides structural support, allowing the top surface recess area to be maximized while maintaining reliability through the three-dimensional geometry of the projection.
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
Enables the formation of larger recess areas on wafers, enhancing device capacity while maintaining wafer strength during grinding.
Implementation Method 1
grinding the back surface of the wafer prepared in the preparing to form a recess and form a projection surrounding the recess
Data Source
AI summary
A wafer processing method for a wafer formed of a semiconductor material includes: preparing a wafer that includes a front surface, a back surface on a rear surface of the front surface, and a side surface ranging from the front surface to the back surface and includes a flat mirror surface portion indicating a crystal orientation of the wafer on the side surface; and grinding the back surface of the wafer prepared in the preparing to form a recess and form a projection surrounding the recess.