Rotating Shower Head for Uniform Etch Rate Control
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Solution Overview
Problem
Dry etching in semiconductor manufacturing faces challenges with etch micro-loading effects, where etch rates vary across different points on a wafer, leading to non-uniformity in etched features and structures with different dimensions and densities, which complicates chip manufacturing.
Innovation Solution
An atomic layer etch (ALE) process using a multi-channel, rotating gas plate to control the ion/radical ratio and reduce transition time between reaction cycles, combined with electrostatic forces to minimize switching time between cycles, ensuring consistent etch rates across the wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dry etching is used, then etching can be performed, but etch micro-loading effects cause non-uniform etch rates across the wafer
Solution Approach 1:
The shower head rotates during the etching process to dynamically change the gas distribution pattern across the wafer surface. This rotation prevents stationary gas channel positions that would cause localized micro-loading effects, thereby achieving more uniform etch rates across different regions of the wafer.
Solution Approach 2:
The rotating shower head creates periodic variation in gas flow distribution to the wafer surface. By cycling through different gas channel alignments with the wafer, the system periodically redistributes reactant delivery, preventing accumulation effects and micro-loading that would occur with static gas distribution.
2Loss of time
If a rotating gas plate is used to control ion/radical ratio, then transition time between reaction cycles is reduced, but device complexity increases
Solution Approach 1:
The rotation mechanism is integrated directly into the shower head structure itself, combining the gas distribution function with the rotation function in a single component. This merging eliminates the need for separate complex positioning mechanisms and reduces overall system complexity while achieving rapid transition between reaction cycles.
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 ALE process effectively reduces etch micro-loading effects by controlling the ion/radical ratio and transition time, resulting in more uniform etching and improved selectivity, enhancing the precision and efficiency of semiconductor manufacturing.
Implementation Method 1
An atomic layer etch (ALE) process using a multi-channel, rotating gas plate to control the ion/radical ratio and reduce transition time between reaction cycles
Implementation Method 2
combined with electrostatic forces to minimize switching time between cycles
Data Source
AI summary
The present disclosure describes an exemplary etch process in a reactor that includes a shower head and an electrostatic chuck configured to receive a radio frequency (RF) power. The shower head includes a top plate and a bottom plate with one or more gas channels that receive incoming gases. The method can include (i) rotating the top plate or the bottom plate of the shower head to a first position to allow a gas to flow through the shower head; (ii) performing a surface modification cycle that includes: applying a negative direct current (DC) bias voltage to the shower head, applying an RF power signal to the wafer chuck; and (iii) performing an etching cycle that includes: removing the negative DC bias voltage from the shower head and lowering the RF power signal applied to the wafer chuck.