Conductive Mask for Charge Dissipation in Semiconductor Etching
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Solution Overview
Problem
The dry etching process in semiconductor manufacturing causes electric charges to accumulate in dielectric layers, leading to metal layer bursts and reduced yield, particularly when etching via holes or trenches, as copper materials are difficult to etch and tend to burst during the process.
Innovation Solution
The use of a conductive mask that disperses and transmits these charges to the substrate, preventing their storage in the dielectric layer, thereby avoiding metal layer bursts and increasing wafer yield. The conductive mask is made from conductive photoresist or a structure covering a metal layer, ensuring charges are not trapped during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dry etching process is used to etch via holes or trenches in the dielectric layer, then the etching precision and depth control are improved, but electric charges accumulate in the dielectric layer causing metal layer bursts
Solution Approach 1:
A conductive mask layer is introduced as an intermediary between the dielectric layer and the metal layer. This conductive mask serves as a charge sink that absorbs and dissipates the electric charges generated during dry etching, preventing charge accumulation that would otherwise cause metal layer bursts. The conductive mask is temporarily added during the etching process and then removed afterward.
Solution Approach 2:
The conductive mask is formed on the dielectric layer before the dry etching process begins. This preliminary action ensures that the charge dissipation pathway is already in place before charges are generated, allowing continuous charge neutralization throughout the etching process and preventing burst formation.
2Reliability
If copper is used as the material for multilevel interconnects, then the electrical conductivity and performance are improved, but the etching difficulty increases causing process complexity
Solution Approach 1:
The conductive mask acts as a mediator that enables the etching of copper-based interconnects by providing a charge dissipation mechanism. This allows the use of copper materials with their superior electrical properties while managing the etching challenges through the intermediate conductive mask layer that prevents charge-related defects.
3Manufacturing precision
If the etching process continues until the metal layer surface is reached, then the via hole depth and connectivity are improved, but charge accumulation causes bursts in the metal layer or underlying components
Solution Approach 1:
The conductive mask converts the harmful effect of charge accumulation into a beneficial charge dissipation mechanism. By providing a conductive pathway, the mask transforms the potentially damaging trapped charges into a controlled charge flow that is safely dissipated, allowing the etching to proceed to the metal layer surface without causing bursts.
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
The conductive mask effectively disperses and transmits charges, preventing metal layer bursts and increasing the yield of semiconductor wafers by ensuring that charges are not stored in the dielectric layer, thus maintaining the integrity of metal interconnects and components during the etching process.
Implementation Method 1
The conductive mask effectively disperses and transmits charges, preventing metal layer bursts and increasing the yield of semiconductor wafers by ensuring that charges are not stored in the dielectric layer
Data Source
AI summary
A method of etching a dielectric layer by a conductive mask includes providing the dielectric layer on a substrate, forming a pattern conductive mask on the dielectric layer, the pattern conductive mask contacting with the substrate, processing a dry etching on the dielectric layer by the pattern conductive mask. Because the conductive mask disperses a lot of electric charges, the electric charges are not able to be stored on the dry etched dielectric layer, and the multilevel interconnects and the elements under the dielectric layer will not burst.