Wafer Susceptor Flow Control Structures for Defect Reduction

Solution Overview

Problem

Defects on semiconductor wafers, particularly near the outer edges, reduce the yield of usable die and increase manufacturing costs due to uneven growth rates and gas interactions during processes like CVD and epitaxial layer formation.

Innovation Solution

A wafer susceptor with a non-uniform surface featuring a flow control structure comprising recesses and protrusions between the wafer pocket and the outer edge, which modifies gas flow dynamics to ensure more uniform reactions across the wafer surface, reducing defects and improving yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional susceptor with a flat surface is used, then the manufacturing process is simple, but defects are formed on certain areas of the semiconductor wafer reducing yield

Engineering Contradiction:

Improvewafer defect reductionVSAvoidsusceptor structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The susceptor surface is modified with flow control structures (recesses and protrusions) at specific locations between the wafer pocket and outer edge. These localized structural variations create different gas flow characteristics in different regions, ensuring uniform reactant distribution across the wafer surface without requiring complete redesign of the entire susceptor.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The susceptor surface is segmented into multiple regions with different characteristics: a central wafer pocket region, intermediate flow control regions with recesses and protrusions, and an outer edge region. This segmentation allows each region to perform its specific function - the flow control structures break up turbulent gas flow into more uniform streams that distribute reactants evenly across the wafer.

Inventive Principle:

Principle #1Segmentation

2Stability of the object's composition

If the susceptor surface is modified to control gas flow, then uniformity of reaction is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveuniformity of epitaxial layer formationVSAvoidsusceptor fabrication

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The susceptor surface geometry is modified by changing physical parameters such as creating recesses with specific depths (e.g., 0.5-2.0 mm) and protrusions with specific heights and spacing. These parameter changes create controlled turbulence and eddy currents in the gas flow, ensuring uniform reactant distribution and consistent epitaxial layer formation across the entire wafer surface.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If a simple susceptor design is used, then manufacturing cost is lower, but yield of good die is reduced due to defects

Engineering Contradiction:

Improveyield of good dieVSAvoidsusceptor structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The susceptor surface is modified with flow control structures (recesses and protrusions) at specific locations between the wafer pocket and outer edge. These localized structural variations create different gas flow characteristics in different regions, ensuring uniform reactant distribution across the wafer surface without requiring complete redesign of the entire susceptor.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The susceptor surface is segmented into multiple regions with different characteristics: a central wafer pocket region, intermediate flow control regions with recesses and protrusions, and an outer edge region. This segmentation allows each region to perform its specific function - the flow control structures break up turbulent gas flow into more uniform streams that distribute reactants evenly across the wafer.

Inventive Principle:

Principle #1Segmentation

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 modified gas flow and increased surface area lead to a 10-25% increase in semiconductor wafer yield by reducing defects and enhancing the uniformity of epitaxial layer formation, thereby lowering manufacturing costs.

Implementation Method 1

modifies gas flow dynamics to ensure more uniform reactions across the wafer surface

Methodology Applied

Scientific EffectGas flow dynamics: Convection

Data Source

PatentUS10068791B2Wafer susceptor for forming a semiconductor device and method therefor

Publication Date: 2018.09.04 SEMICON COMPONENTS IND LLC

AI summary

In one embodiment, a wafer susceptor is formed to have portion of the susceptor that is positioned between a wafer pocket and an outside edge of the susceptor to have a non-uniform and/or a non-planar surface. In another embodiment, the non-uniform and/or non-planar surface includes one of a recess into the surface or a protrusion extending away from the surface.