Plasma Etching Apparatus Segmented Gas Injection for Wafer Uniformity
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Solution Overview
Problem
The existing method of dividing semiconductor wafers along predetermined division lines using plasma etching faces challenges in achieving uniform etching rates, leading to inconsistent results.
Innovation Solution
A plasma etching apparatus with a housing and processing gas injecting means featuring a central and peripheral injecting portion, controlled by high-frequency valves, ensures uniform etching by agitating the processing gases effectively within the plasma processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma etching is used to divide semiconductor wafers along predetermined division lines, then chips and stress in the peripheries of semiconductor devices are eliminated, but the etching rate varies and uniform etching cannot be performed
Solution Approach 1:
The processing gas injecting means is divided into a central injecting portion and a peripheral injecting portion, with separate processing gas supply paths for each. This segmentation allows independent control of gas flow to different regions of the semiconductor wafer, enabling uniform etching rate across the entire wafer surface despite variations in distance from the center.
Solution Approach 2:
Different regions of the semiconductor wafer receive processing gas through dedicated supply paths - the central region through the central injecting portion and the peripheral region through the peripheral injecting portion. This local quality approach addresses the specific needs of each region to achieve overall uniformity in etching performance.
2Ease of manufacture
If a rotating cutting blade is used to cut the semiconductor wafer, then division along predetermined lines is achieved, but small chips and stress occur in the peripheries of semiconductor devices
Solution Approach 1:
The mechanical cutting blade system is replaced with a plasma etching system that uses plasma to remove material along predetermined division lines. This substitution eliminates the mechanical contact that causes chips and stress, particularly at the peripheries of semiconductor devices, while maintaining the capability to divide wafers accurately.
Solution Approach 2:
The invention changes the fundamental parameter of the division process from mechanical cutting to plasma-based etching. By controlling plasma parameters such as gas flow rate, power, and pressure through the segmented injecting system, the process achieves clean division without the mechanical damage that reduces transverse rupture strength.
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 ensures a uniform etching rate across the semiconductor wafer, preventing chip formation and stress at the periphery of semiconductor devices, thereby enhancing the transverse rupture strength.
Implementation Method 1
processing gas injecting means for injecting a processing gas for plasma generation onto the workpiece retained by the workpiece retaining means
Implementation Method 2
control means for controlling an opening and closing frequency of the first high-frequency opening and closing valve and an opening and closing frequency of the second high-frequency opening and closing valve
Data Source
AI summary
A plasma etching apparatus includes: a housing defining a plasma processing chamber; a workpiece retaining unit disposed within the plasma processing chamber of the housing and retaining a workpiece on an upper surface of the workpiece retaining unit; a processing gas injecting unit injecting a processing gas for plasma generation onto the workpiece retained by the workpiece retaining unit, the processing gas injecting unit including a processing gas jetting portion; a processing gas supply unit supplying the processing gas to the processing gas injecting unit; and a pressure reducing unit reducing a pressure within the plasma processing chamber. The processing gas jetting portion of the processing gas injecting unit includes a central injecting portion and a peripheral injecting portion surrounding the central injecting portion.