Thermal Oxidation for Buried Interface Roughness Control

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Solution Overview

Problem

Existing methods for manufacturing semiconductor components with specific surface roughness for preventing untimely bonding are difficult to control and adapt, particularly in MEMS fabrication where a rough buried interface is required to maintain membrane mobility.

Innovation Solution

A method involving thermal oxidation of a semiconductor substrate to form an oxide layer with a buried interface of controlled roughness, allowing for the assembly of substrates with specific surface roughness to prevent bonding, including mechanical polishing and etching techniques to achieve desired properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods are used to provide substrate roughness for preventing bonding, then bonding prevention is achieved, but control of the amount of roughness is difficult or impossible

Engineering Contradiction:

Improvecontrol of surface roughnessVSAvoiddifficulty in providing specific roughness

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by systematically varying oxidation temperature, oxidation time, and oxide layer thickness to precisely control the roughness of the buried interface. By changing these parameters, the invention achieves controlled roughness values that prevent bonding while maintaining manufacturability, directly resolving the contradiction between precision control and ease of manufacture.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a rough buried interface is created to prevent bonding, then membrane mobility is maintained, but the process becomes difficult to adapt to different roughness requirements

Engineering Contradiction:

Improveadaptability to different roughness requirementsVSAvoidcomplexity of roughness control process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention achieves adaptability by establishing systematic relationships between oxidation parameters (temperature, time, thickness) and the resulting buried interface roughness. This allows the process to be adapted to different roughness requirements by simply adjusting these parameters, making the complex process controllable and versatile for various applications.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs feedback mechanisms by measuring and characterizing the buried interface roughness after oxidation, then using this information to adjust oxidation parameters for subsequent batches. This feedback loop enables precise adaptation to different roughness requirements while managing process complexity through systematic control.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If thermal oxidation is performed to form oxide layer, then buried interface roughness is controlled, but additional processing steps are required

Engineering Contradiction:

Improveprecision of buried interface roughnessVSAvoidnumber of processing steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the oxide layer formation process with the buried interface roughness creation process. By performing thermal oxidation that simultaneously forms the oxide layer and creates the desired buried interface roughness in a single operation, the invention achieves precision control without proportionally increasing device complexity, as these functions are combined rather than performed as separate steps.

Inventive Principle:

Principle #5Merging (Combining)

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

Enables precise control of surface roughness, preventing untimely bonding and enhancing the flexibility in manufacturing semiconductor components like membranes and mobile parts, particularly in MEMS applications, by forming a semiconductor component with a rough buried interface.

Implementation Method 1

thermally oxidizing the first surface of the first semiconductor substrate to form an oxide layer defining an external oxide surface on the first semiconductor substrate and a buried oxide-semiconductor interface below the oxide surface

Methodology Applied

Scientific EffectThermal oxidation: Oxidation

Data Source

PatentUS7807548B2Process of forming and controlling rough interfaces

Publication Date: 2010.10.05 SOITEC SA

AI summary

The invention provides a method for forming a semiconductor component with a rough buried interface. The method includes providing a first semiconductor substrate having a first surface of roughness R1. The method further includes thermally oxidizing the first surface of the first semiconductor substrate to form an oxide layer defining an external oxide surface on the first semiconductor substrate and a buried oxide-semiconductor interface below the oxide surface, so that the buried oxide surface has a roughness R2 that is less than R1. The method also includes assembling the oxide surface of the first semiconductor substrate with a second substrate. The invention also provides a component formed according to the method of the invention.