Plasma Etching Shower Head Segmentation for Wafer Uniformity
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Solution Overview
Problem
Achieving uniformity in the etching profiles of via holes and trenches within a wafer plane is challenging due to difficulties in independently controlling profile parameters such as width, diameter, and depth, leading to disparities in etch rates across the wafer plane during plasma etching processes.
Innovation Solution
A plasma etching method that includes a temperature adjustment unit to maintain uniform substrate temperature and a supply rate adjustment unit to control the concentration distribution of active species, using a plasma etching apparatus with a shower head divided into regions for tailored etching gas supply based on the Peclet number, ensuring uniform etching conditions across the wafer plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wafer hole diameter is enlarged, then the device performance is improved, but the in-plane etch rate uniformity deteriorates
Solution Approach 1:
The shower head is segmented into multiple regions with different gas supply characteristics to compensate for the increased difficulty of maintaining uniformity in larger diameter holes. Each region independently controls the active species density and etching conditions to achieve uniform etch rates across the expanded wafer area
Solution Approach 2:
The system changes multiple parameters simultaneously including gas supply rate, Peclet number, and active species density distribution across different regions. By adjusting these parameters in a coordinated manner, the patent maintains etch rate uniformity even as wafer hole diameter increases
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 method achieves improved in-plane uniformity of etch rates and profiles by adjusting etching gas supply conditions according to the effect of diffusion or flow, resulting in consistent etching results across the wafer plane, even with different etching gases and films.
Implementation Method 1
Plasma etching that involves irradiating plasma on an etching film (or etching substrate) to etch the film or substrate is an indispensable process for semiconductor device manufacturing. In plasma etching, etching gas is activated by a high frequency electric field to generate plasma.
Implementation Method 2
a temperature adjustment unit for adjusting a temperature of the substrate placed on a stage along a radial direction
Implementation Method 3
adjusting a supply rate of etching gas supplied to the substrate... adjusting a concentration distribution of active species contained in the plasma generated by the plasma generation unit within the space above the substrate
Implementation Method 4
adjusting an etching gas supply condition according to whether a supply position on the substrate corresponds to a position where an effect of diffusion of supplied etching gas is greater than an effect of flow of supplied etching gas
Implementation Method 5
The surface of a wafer as the etching object reacts with the ions and radicals contained in the plasma to prompt the generation of reaction products, and etching of the wafer progresses as the reaction products are volatized.
Data Source
AI summary
A plasma etching method for etching a substrate includes an adjustment step adjusting a concentration distribution of active species contained in plasma. The adjustment step adjusts a supply rate of an etching gas according to whether a supply region on a substrate to which the etching gas is supplied corresponds to a region where an effect of diffusion of the supplied etching gas is greater than an effect of flow of the supplied etching gas or a region where the effect of flow of the supplied etching gas is greater than the effect of diffusion of the supplied etching gas.