Semiconductor Wafer TEG Removal via Plasma Etching and Protective Sheet
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Solution Overview
Problem
Conventional semiconductor chip manufacturing methods face challenges in completely removing Test Element Groups (TEGs) during plasma dicing, leading to potential short circuits and circuit failures due to residual TEGs, and require time-consuming gas type changes for efficient etching.
Innovation Solution
A method involving forming semiconductor devices and TEGs on a semiconductor wafer with dividing regions that include a TEG-placement portion and region-width-reduced portions, where a protective sheet is applied to stick to the TEG, and plasma etching is performed to divide the chips, allowing the TEG to be efficiently removed by peeling off the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the TEG formation region is reduced to narrow the dividing region, then the number of semiconductor chips per wafer increases, but the TEG cannot be completely removed by cutting and remains unremoved, causing short circuiting or circuit failure
Solution Approach 1:
The dividing region is segmented into two distinct portions: a first portion with a first width that accommodates the TEG, and a second portion with a second width smaller than the first width that enables complete removal. This segmentation allows the TEG to be fully removed through the narrower second portion while maintaining adequate space in the first portion for reliable TEG formation and electrical measurements.
Solution Approach 2:
Different widths are applied to different portions of the dividing region based on local requirements. The first portion has a larger width optimized for TEG formation and measurement reliability, while the second portion has a smaller width optimized for complete TEG removal during dicing, ensuring each region has the quality needed for its specific function.
2Productivity
If plasma dicing is used to divide the wafer, then the dividing process is efficient, but the TEG cannot be completely removed because it is formed of metals and inorganic substances that resist fluorine-based plasma etching
Solution Approach 1:
A protective sheet is introduced as an intermediary element that is adhered to the TEG before plasma dicing. The sheet serves as a mediator that allows the TEG to be completely removed from the wafer during the plasma dicing process by being carried away with the etched material, while the TEG itself remains intact for subsequent removal from the sheet.
Solution Approach 2:
The protective sheet is adhered to the TEG in advance of the plasma dicing process. This preliminary action prepares the TEG for complete removal by providing a carrier that will facilitate its extraction during dicing, ensuring that the TEG is fully removed without requiring subsequent manual intervention.
3Area of stationary object
If the dividing region width is reduced to expand device-formation-regions, then chip area increases, but the gap between the edge portion of the TEG formation region and the edge portion of the dividing region becomes too small, making complete TEG removal difficult
Solution Approach 1:
The dividing region is divided into two width portions that serve different functions: the first portion provides adequate spacing for TEG formation and measurement, while the second portion provides the narrow gap needed for complete TEG removal. This segmentation allows the device-formation-regions to be maximized while ensuring complete TEG extraction.
Solution Approach 2:
The dividing region exhibits local quality variation with different widths at different locations. The first portion has a larger width suitable for TEG formation, while the second portion has a smaller width optimized for complete removal, allowing the device-formation-regions to expand while maintaining manufacturing precision for TEG removal.
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 complete removal of TEGs without changing etching gases, reducing the area of dividing regions, increasing chip density, and expanding device-formation-regions, thus enhancing manufacturing efficiency and preventing circuit failures.
Implementation Method 1
performing plasma etching on a second surface which is a surface located opposite from the first surface of the wafer in a state that the protective sheet is stuck to and the mask is placed on, thereby portions corresponding to the dividing regions are removed
Data Source
AI summary
In a semiconductor wafer that has semiconductor devices arranged in a plurality of device-formation-regions and a TEG placed in dividing regions that define the device-formation-regions, a TEG-placement portion is arranged in the dividing regions partially expanded in width, and the TEG is placed in the TEG-placement portion. Additionally, a protective sheet is stuck to the semiconductor wafer, then plasma etching is performed, and the TEG is removed in a state where it remains in the dividing region and stuck to the protective sheet together with the protective sheet by peeling off the protective sheet, thereby the device-formation-regions are divided into individual pieces, and the semiconductor chips are manufactured.