Wafer Repair by Laser Defect Removal and Chip Replacement
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Solution Overview
Problem
The manufacturing of laminated device chips is hindered by the presence of defective semiconductor devices in wafers, leading to a significant decrease in yield due to the need to discard entire chips containing even a single defective device.
Innovation Solution
A method involving the removal of defective device regions from wafers using a laser beam, followed by fitting non-defective device chips into the removed regions, and subsequent lamination and division to form defect-free laminated device chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafers including defective devices are used to manufacture laminated device chips, then the manufacturing process can proceed without additional steps, but the yield decreases significantly due to defective chips
Solution Approach 1:
The patent applies preliminary action by removing defective device regions from wafers before the lamination process. Inspection is performed to identify defective devices, and laser processing removes the defective regions in advance. This prevents defective devices from being incorporated into laminated device chips, thereby improving yield while maintaining manufacturing efficiency.
Solution Approach 2:
The patent extracts defective device regions from wafers using laser processing. The laser removes the defective regions along with surrounding sacrificial layers, creating holes that are then filled with non-defective device chips. This extraction eliminates the harmful defective devices from the manufacturing process while preserving the overall wafer structure for continued production.
2Reliability
If defective device regions are removed from wafers using laser processing, then chip yield improves by eliminating defective chips, but the manufacturing process complexity increases
Solution Approach 1:
The patent replaces traditional mechanical cutting and sorting methods with laser processing. The laser precisely removes defective device regions without requiring physical contact or complex mechanical tooling. This substitution simplifies the overall process by using a single, highly controllable energy source that can selectively remove material based on pre-identified defective locations.
Solution Approach 2:
The patent utilizes parameter changes in the laser processing system to control the removal of defective regions. By adjusting laser power, pulse duration, and scanning speed, the process precisely removes defective devices while preserving surrounding non-defective areas. This parameter control enables selective removal without increasing overall process complexity.
3Reliability
If non-defective device chips are fitted into removed regions, then the number of defective chips is minimized, but additional processing steps are required
Solution Approach 1:
The patent merges the defective region removal process with the device chip integration process. The laser creates holes by removing defective regions, and these same holes are immediately filled with non-defective device chips. This merging eliminates the need for separate removal and filling operations, reducing the total number of processing steps while ensuring high-quality laminated device chips.
Solution Approach 2:
The patent uses sacrificial layers as intermediaries during the fitting process. These sacrificial layers are positioned between the wafer and the device chips being fitted, facilitating precise alignment and secure bonding. The intermediaries enable the fitting operation to proceed smoothly without requiring complex alignment mechanisms or additional bonding 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 effectively suppresses the decrease in yield by ensuring that only non-defective device chips are used in the laminated device chips, thereby improving the manufacturing efficiency and reducing waste.
Implementation Method 1
The removing step destroys the defective device region by irradiating the defective device region with a laser beam
Data Source
AI summary
A wafer manufacturing method includes a wafer preparing step of preparing a wafer including a semiconductor device formed in each of a plurality of regions demarcated by a plurality of streets intersecting each other, a removing step of removing, from the wafer, a defective device region including a semiconductor device determined to be a defective product among a plurality of the semiconductor devices formed in the wafer, and a fitting step of fitting, into a removed region formed by removing the defective device region from the wafer, a device chip including a semiconductor device as a non-defective product having same functions as those of the semiconductor device determined to be a defective product and having a size capable of being fitted into the removed region.