Ringed Susceptor Structure for Backside Deposition Control

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Solution Overview

Problem

Semiconductor substrates experience issues such as sliding, sticking, and backside deposition during processing due to inadequate gas flow control and substrate positioning, leading to uneven heating and thickness inconsistencies.

Innovation Solution

A susceptor design featuring a radially outward section with angled rings and a gridded, partially concave radially inward section to prevent backside deposition and substrate movement, ensuring precise substrate positioning and controlled gas flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If process gases flow freely between substrate and susceptor, then gas flow control is simple, but backside deposition occurs causing thickness inconsistencies

Engineering Contradiction:

Improvesubstrate thickness consistencyVSAvoidsusceptor structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The susceptor surface is segmented into multiple functional zones: a radially inward section with a gridded surface for substrate contact and gas flow control, and a radially outward section with rings to prevent backside deposition. This segmentation allows each zone to perform its specific function independently, solving the contradiction by controlling gas flow without requiring complex overall device structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the susceptor are given different surface properties: the radially inward section has a gridded surface with specific contact characteristics, while the radially outward section has rings with different geometric properties. This local differentiation enables precise control of gas flow and substrate positioning without complicating the entire susceptor design.

Inventive Principle:

Principle #3Local quality

2Reliability

If substrate is held in a recess with gas cushion, then substrate positioning is simplified, but substrate sliding occurs during drop off

Engineering Contradiction:

Improvesubstrate positioning accuracyVSAvoidsubstrate loading process

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The gridded surface on the radially inward section is designed to control gas flow in advance during the substrate drop-off process. The grid structure allows gas to escape through controlled pathways before the substrate fully contacts the susceptor, preventing sliding by ensuring the substrate settles in the correct position without excessive lateral movement.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If susceptor uses simple circular shape, then manufacturing is simplified, but substrate positioning and gas flow control become inadequate

Engineering Contradiction:

Improvesubstrate positioning precisionVSAvoidsusceptor fabrication

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The susceptor is segmented into radially inward and outward sections with distinct features (gridded surface and rings), allowing precise substrate positioning and gas flow control while maintaining a fundamentally simple circular geometry that is easy to manufacture.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11885019B2Susceptor with ring to limit backside deposition

Publication Date: 2024.01.30 ASM IP HLDG BV

AI summary

A susceptor including a generally circular body having a face with a radially inward section and a radially outward section proximate a circumference of the body, the radially outward section having at least one ring extending upward for contacting a bottom surface of a substrate, and wherein the radially inward section lacks a ring extending upward from the face.