Partial Etching Liquid Replacement for Semiconductor Wafer Processing

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Solution Overview

Problem

Conventional wet etching methods for semiconductor wafers face challenges in maintaining precise etching processing due to varying silicon concentrations in the etching liquid, requiring frequent replacement and complicating the processing time with necessary liquid adjustments.

Innovation Solution

An etching method and apparatus that implement a partial replacement pattern, discharging and supplying etching liquid in specific set amounts to maintain a constant silicon concentration, eliminating the need for complete liquid replacement and simplifying the etching process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the etching liquid is completely replaced regularly, then the silicon concentration in the etching liquid is temporarily reduced, but the etching processing precision deteriorates and liquid adjustment becomes complicated

Engineering Contradiction:

Improvesilicon concentration in etching liquidVSAvoidetching processing precision

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

Instead of completely replacing the etching liquid, the invention applies partial replacement by discharging a specific amount (first set amount) and supplying a new etching liquid (second set amount) during the etching step, and discharging another amount (third set amount) and supplying another new etching liquid (fourth set amount) during the interval step. This partial replacement maintains the silicon concentration within a determined range, preserving etching precision while avoiding the complications of complete liquid replacement and seasoning adjustments.

Inventive Principle:

Principle #16Partial or excessive action

2Quantity of substance

If the etching liquid is completely replaced regularly, then the silicon concentration can be reset, but the processing time is increased due to liquid adjustment

Engineering Contradiction:

Improvesilicon concentration controlVSAvoidprocessing time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The invention replaces only a portion of the etching liquid rather than the entire volume. During the etching step, a first set amount is discharged and a second set amount of new etching liquid is supplied. During the interval step, a third set amount is discharged and a fourth set amount of new etching liquid is supplied. This partial replacement approach maintains silicon concentration control while significantly reducing the time required compared to complete liquid replacement and seasoning procedures.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If the etching liquid is not replaced, then the processing time is reduced, but the etching precision deteriorates due to silicon concentration increase

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidetching precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention maintains continuous etching processing by implementing partial liquid replacement at specific intervals (during etching step and interval step) rather than stopping for complete replacement. This continuous partial replacement keeps the silicon concentration within the determined range, ensuring etching precision is maintained throughout the processing without significant interruptions, thus preserving high productivity.

Inventive Principle:

Principle #20Continuity of useful action

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

This approach allows for precise etching processing by maintaining the silicon concentration within a determined range without complete liquid replacement, reducing processing time and simplifying adjustments.

Implementation Method 1

an etching processing has been performed on a nitride film-oxide film by using phosphoric acid as an etching liquid

Methodology Applied

Scientific EffectWet etching:

Implementation Method 2

circularly supplying the etching liquid of the predetermined temperature through a circulation line connected to the processing bath, and a circulation pump

Methodology Applied

Scientific EffectPumping: Pump

Implementation Method 3

heating an etching liquid composed of, for example, a phosphoric acid aqueous solution (H3PO4), which is stored in a processing bath, to a predetermined temperature, for example, 160° C. to 180° C.

Methodology Applied

Scientific EffectHeating: Heating

Data Source

PatentUS9887092B2Etching method, etching apparatus, and storage medium

Publication Date: 2018.02.06 TOKYO ELECTRON LTD

AI summary

Provided is an etching method including: an etching step of performing an etching processing using an etching liquid on a workpiece accommodated in an etching processing unit; and an interval step between the etching step on the workpiece and a next etching step on another workpiece. The etching step includes a first partial replacement pattern including discharging the etching liquid in the etching processing unit provided for the etching processing by a first set amount, and supplying a new etching liquid into the etching processing unit by a second set amount, and the interval step includes a second partial replacement pattern including discharging the etching liquid in the etching processing unit provided for the etching processing by a third set amount, and supplying a new etching liquid into the etching processing unit by a fourth set amount.