Actively Cooled Grid Assembly for Plasma Substrate Processing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Substrate processing systems face challenges in maintaining the temperature of gas distribution devices, particularly showerheads, as the size of substrates increases, leading to unacceptable heating due to higher RF power requirements, with existing cooling solutions like brazed and gun drilled designs being unreliable or costly.

Innovation Solution

A grid assembly with a cooled grid structure, comprising an upper and lower portion with tubes that isolate plasma and filter ions, using cooling fluid to prevent melting, and an ion-filtering pattern that includes a faceplate, allowing for increased plasma power without exceeding the faceplate's maximum operating temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If RF power is increased to maintain ash rate for larger substrates, then productivity is improved, but temperature of the plate increases to unacceptable levels

Engineering Contradiction:

Improveash rateVSAvoidplate temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent implements water cooling channels integrated into the showerhead plate, using hydraulic flow to remove heat from the plate. Cooling fluid is circulated through channels formed in the plate to actively dissipate the heat generated by RF plasma, allowing higher RF power to be applied without exceeding temperature limits.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the thermal management parameters of the showerhead by introducing active cooling. The cooling system allows the plate temperature to be maintained within acceptable ranges even when RF power is increased, effectively decoupling the relationship between power input and temperature rise.

Inventive Principle:

Principle #35Parameter changes

2Temperature

If brazed showerhead designs are used to allow water cooling, then temperature control is improved, but reliability decreases

Engineering Contradiction:

Improveplate temperatureVSAvoidshowerhead reliability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The showerhead is segmented into modular components including the plate, cooling channels, and tube array that can be independently manufactured and assembled. This modular construction avoids the reliability issues of brazed joints by using mechanical assembly methods such as interference fits or threaded connections between components.

Inventive Principle:

Principle #1Segmentation

3Temperature

If gun drilled showerhead designs are used to allow water cooling, then temperature control is improved, but manufacturing cost increases

Engineering Contradiction:

Improveplate temperatureVSAvoidmanufacturing cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The cooling channels are designed to be self-formed during the injection molding process of the showerhead plate. The channels are integrated into the mold cavity, allowing the cooling passages to be created automatically during normal production without requiring additional post-processing operations like gun drilling, thereby reducing manufacturing complexity and cost.

Inventive Principle:

Principle #25Self-service

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 cooled grid assembly effectively reduces the faceplate temperature by approximately 50° C to over 200° C, maintaining ash rates similar to brazed and gun drilled showerhead designs while supporting larger substrates without reliability or cost issues.

Implementation Method 1

The cooled grid assembly effectively reduces the faceplate temperature by approximately 50° C to over 200° C

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

using cooling fluid to prevent melting

Methodology Applied

Scientific EffectConvection cooling: Convection

Implementation Method 3

The plurality of tubes isolates the plasma from the substrate while filtering unwanted and damaging ions

Methodology Applied

Scientific EffectIon filtering: Ion Repulsion/Attraction

Data Source

PatentUS9679749B2Gas distribution device with actively cooled grid

Publication Date: 2017.06.13 LAM RES CORP

AI summary

A grid assembly for a substrate processing system includes a first portion including a first body defining a central opening, an inlet, an outlet, and an upper manifold that is located in the first body and that is in fluid communication with the inlet or the outlet. A second portion is arranged adjacent to the first portion and includes a second body defining a central opening. A plurality of tubes is arranged in the central opening of the second body. First ones of the plurality of tubes are in fluid communication with the upper manifold. A lower manifold is located in the second body and is in fluid communication with the other one of the inlet or the outlet. Second ones of the plurality of tubes are in fluid communication with the lower manifold. The grid assembly is arranged between a remote plasma source and a substrate.