Wafer Boat Support Layout for Sagging Compensation
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Solution Overview
Problem
Sagging of semiconductor wafers in wafer boats due to gravitational stress reduces accessibility and maneuverability for wafer handling equipment, leading to decreased wafer capacity and process efficiency.
Innovation Solution
A wafer boat design with at least one back support positioned lower than the lateral supports to compensate for sagging, ensuring that the front side portion of the wafer is partially supported, and optionally incorporating shield rings to enhance deposition uniformity and accessibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vertical spacing between holding positions is increased to prevent wafer sagging, then wafer accessibility is improved, but wafer capacity per boat is decreased
Solution Approach 1:
The patent applies local quality by positioning the back support at a different vertical level than the lateral supports. Specifically, the back support is located at a lower vertical position to provide targeted support to the front side portion of wafers where sagging occurs, while maintaining standard vertical spacing between holding positions. This localized support approach prevents wafer sagging without requiring increased vertical spacing, thereby maintaining both wafer accessibility and high wafer capacity per boat.
2Ease of operation
If vertical spacing between holding positions is increased to improve wafer accessibility, then end effector maneuverability is improved, but process efficiency is reduced
Solution Approach 1:
The patent implements local quality by providing targeted gravitational compensation through the lower-positioned back support. This localized support structure compensates for wafer sagging in the front side portion without requiring global changes to the vertical spacing between holding positions. As a result, end effector maneuverability is maintained at high levels while process efficiency is preserved through maximized wafer capacity per boat.
3Ease of manufacture
If conventional rod arrangement is used with wafers mostly unsupported, then wafer insertion and removal is simplified, but wafer sagging increases
Solution Approach 1:
The patent applies local quality by adding a specifically positioned back support that provides gravitational compensation to the front side portion of wafers. This localized support structure addresses the wafer sagging issue without changing the overall rod arrangement configuration that enables simple wafer insertion and removal. The back support is integrated into the existing rod structure, maintaining ease of wafer handling while improving wafer flatness through targeted support.
Solution Approach 2:
The patent implements preliminary anti-action by pre-positioning the back support at a lower vertical level to counteract the gravitational force that causes wafer sagging. This preventive measure is built into the wafer boat structure, so that gravitational compensation is automatically provided as wafers are inserted, without requiring active control or adjustment during the wafer handling process.
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 design minimizes wafer sagging, increasing the accessible space between wafers and improving the efficiency of wafer handling by maintaining the centerline sections parallel to the horizontal plane, thus enhancing the accessibility and maneuverability for wafer handling equipment.
Implementation Method 1
sagging of a front side portion of an inserted wafer near the front side of the wafer boat due to gravity is at least partially compensated for
Data Source
AI summary
Wafer boat for holding semiconductor wafers in a spaced vertical arrangement during processing, said wafer boat comprising a plurality of vertically spaced holding positions for receiving and supporting said wafers in a substantially horizontal orientation, wherein the holding positions can be accessed from a front side of the wafer boat to allow for insertion and removal of a wafer, wherein at least one holding position comprises a back support for engaging a back side portion of a wafer and two lateral supports for engaging opposite lateral side portions of the wafer, and wherein the back support is disposed at a lower position than said two lateral supports such that sagging of a front side portion of an inserted wafer near the front side of the wafer boat due to gravity is at least partially compensated for.