Wafer Boat Assembly Segmented Cover for Automated Loading

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Solution Overview

Problem

Existing loading systems for vertical furnaces in semiconductor manufacturing require large clearances between wafers and covers to prevent scratching, which compromises film thickness uniformity and are not compatible with automated processes, limiting throughput and efficiency.

Innovation Solution

A wafer boat assembly with a first and second cover part, where the second part has receiving slots for horizontal substrate placement, allowing for automated loading with minimal clearance and easy handling, enabling efficient and automated loading of semiconductor substrates into a vertical furnace.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If large clearance is provided between wafer edge and cover to prevent scratching during insertion, then reliability is improved, but manufacturing precision deteriorates due to compromised film thickness uniformity

Engineering Contradiction:

Improveprevention of scratchingVSAvoidfilm thickness uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The cover is divided into a fixed first cover part and a movable second cover part. The second cover part can be displaced independently to provide large clearance during insertion while maintaining small clearance during processing, thus preventing scratching while ensuring film thickness uniformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second cover part is designed to be movable relative to the first cover part, allowing the clearance between wafer edge and cover to be dynamically adjusted. During insertion, the second cover part is displaced to provide large clearance; during processing, it returns to maintain small clearance for uniformity.

Inventive Principle:

Principle #15Dynamics

2Manufacturing precision

If manual handling of cover plates is used to achieve small clearance, then manufacturing precision is improved, but ease of operation deteriorates due to incompatibility with automated processes

Engineering Contradiction:

Improvefilm thickness uniformityVSAvoidcompatibility with automated processes

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The manual mechanical handling of cover plates is replaced with an automated displacement mechanism. The second cover part is equipped with a displacement mechanism that can be automatically controlled by a loading apparatus, enabling small clearance to be maintained while being compatible with automated processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If complex robot systems are used to automate cover placement, then extent of automation is improved, but device complexity increases

Engineering Contradiction:

Improveautomated cover placementVSAvoidsystem complexity

Core Design Contradiction:

Extent of automationVSDevice complexity

Solution Approach 1:

Instead of using a complex robot system to handle the entire cover, the cover is segmented into two parts, with only the second cover part being movable and requiring automation. This reduces the complexity of the automated system while achieving the desired functionality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The displacement mechanism acts as an intermediary between the automated loading apparatus and the second cover part. This simplified intermediary mechanism is easier to automate than direct robot handling of cover plates, reducing overall system complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of operation

If the entire boat is removed and reinserted for loading, then ease of operation is improved, but loss of time increases due to extended loading/unloading cycles

Engineering Contradiction:

Improveloading processVSAvoidloading time

Core Design Contradiction:

Ease of operationVSLoss of time

Solution Approach 1:

The cover is segmented into fixed and movable parts, allowing the second cover part to be displaced for loading while the boat remains in place. This eliminates the time-consuming removal and reinsertion of the entire boat, reducing loading time while maintaining ease of operation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second cover part is displaced to create loading access before the actual loading operation begins, and then returned to position during or after loading. This preliminary action enables faster loading cycles compared to removing and reinserting the entire boat.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8641350B2Wafer boat assembly, loading apparatus comprising such a wafer boat assembly and method for loading a vertical furnace

Publication Date: 2014.02.04 ASM INTERNATIONAL NV

AI summary

A wafer boat assembly for use with a loading apparatus configured to insert the wafer boat assembly loaded with semiconductor substrates into a furnace. The wafer boat assembly includes a first wafer boat part comprising a base and a first cover part mounted on the base; and a second wafer boat part comprising a second cover part that is provided with receiving slots for holding a plurality of semiconductor substrates. The second cover part has an arcuate shape that extends from a first longitudinal edge to a second longitudinal edge. The first and second wafer boat parts are detachably connectable, such that they mate together to extend around an outer perimeter of a loaded substrate at a predetermined distance.