TEG Removal via Plasma Dicing and Protective Sheet Peeling
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Solution Overview
Problem
Conventional semiconductor chip manufacturing methods using plasma dicing struggle to completely remove Test Element Groups (TEGs) formed of metals and inorganic substances, leading to potential short circuits and circuit failures due to residual TEGs, and require time-consuming gas type changes during plasma etching.
Innovation Solution
A method involving sticking a protective sheet to the semiconductor wafer, performing plasma etching with a mask to separate device-formation-regions, and then peeling off the protective sheet to remove the remaining TEGs, allowing for efficient separation of semiconductor chips without direct connection to the devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma dicing is used to divide the wafer, then manufacturing efficiency is improved and mechanical chipping is reduced, but TEGs formed of metals and inorganic substances cannot be completely removed
Solution Approach 1:
The patent divides the removal process into two distinct stages: first using plasma dicing to separate the wafer into individual chips, then using a separate etching process with appropriate etching solution to remove the TEGs. This segmentation of the removal process allows each stage to be optimized for its specific function, solving the contradiction between manufacturing efficiency and complete TEG removal.
Solution Approach 2:
The patent changes the chemical parameters by selecting specific etching solutions (such as aqua regia or a mixture of nitric acid and hydrofluoric acid) that are chemically effective against metal and inorganic substances. This parameter change enables complete TEG removal while maintaining the benefits of plasma dicing, as the etching solution selectively removes TEG materials without affecting the semiconductor devices.
2Reliability
If gas type is changed during plasma etching to remove TEGs, then complete TEG removal is achieved, but time and labor are increased
Solution Approach 1:
The patent extracts the TEG removal function from the plasma etching process by using a separate wet etching step with chemically appropriate solutions. This extraction eliminates the need to change gas types during plasma etching, as the TEG removal is handled by a different process mechanism, thereby reducing time and labor while achieving complete TEG removal.
Solution Approach 2:
The patent introduces an intermediary etching solution (such as aqua regia or acid mixture) that acts as a mediator between the plasma dicing process and the final chip product. This intermediary substance efficiently removes TEGs without requiring modifications to the plasma etching process, thus avoiding time-consuming gas type changes while ensuring complete TEG removal.
3Productivity
If dividing regions are narrowed to increase chip density, then productivity is improved, but TEG removal becomes incomplete due to insufficient cutting distance from device regions
Solution Approach 1:
The patent replaces the purely mechanical cutting approach with a combination of plasma dicing and chemical etching. The chemical etching process can precisely remove TEGs down to the device region boundaries regardless of the physical width of the dividing regions, enabling complete TEG removal even when dividing regions are narrowed to increase chip density.
Solution Approach 2:
The patent changes from relying on mechanical cutting depth and distance parameters to using chemical etching parameters (etching solution composition, exposure time, temperature) to control TEG removal. This parameter change allows complete TEG removal independent of dividing region width, thus resolving the contradiction between chip density and complete TEG removal precision.
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 during semiconductor chip manufacturing, preventing short circuits and improving manufacturing efficiency by eliminating the need for gas type changes during plasma etching, while also allowing for maskless dicing to enhance chip strength.
Implementation Method 1
performing plasma etching on the second 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
A semiconductor chip manufacturing process includes sticking a protective sheet onto a first surface of a semiconductor wafer so that the sheet comes in contact with the TEG, placing a mask on a second surface that is a surface opposite from the first surface, performing plasma etching on the second surface to remove portions corresponding to dividing regions and separate device-formation-regions into individual semiconductor chips, and removing the TEG in a state where it remains unremoved in the dividing regions and stuck to the protective sheet together with the protective sheet by peeling off the protective sheet.