Semiconductor Etching Measurement Using Growth Layer Thickness Mapping
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Solution Overview
Problem
Existing methods for measuring polishing and etching amounts on semiconductor substrates face accuracy issues, particularly when measuring away from the end surface, and there is a lack of methods for accurately controlling etching amounts during simultaneous growth and etching processes.
Innovation Solution
A method involving measuring the thickness of the semiconductor substrate before and after heat treatment, calculating the growth layer thickness, and determining the etching amount by subtracting the post-treatment thickness from the pre-treatment thickness, using non-destructive methods like FTIR and Raman spectroscopy for growth layer thickness measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the polishing amount is calculated from the chamfered shape applied to the end surface of the semiconductor substrate, then the measurement method is simple, but the accuracy of measurement decreases as the distance from the end surface increases
Solution Approach 1:
The patent transitions from one-dimensional end surface measurement to two-dimensional surface mapping by measuring thickness at multiple positions across the substrate surface. This dimensional expansion allows accurate etching amount calculation at any location, not just near the end surface.
Solution Approach 2:
The substrate surface is divided into multiple measurement positions, and the etching amount is calculated separately for each position. This segmentation approach enables localized accuracy while maintaining overall measurement comprehensiveness across the entire substrate surface.
2Productivity
If both surfaces of the wafer are simultaneously polished using double-sided polishing method, then productivity is improved, but it becomes difficult to measure the polishing amount for each polished surface
Solution Approach 1:
The patent introduces an intermediary reference surface (the opposite surface of the substrate) that remains unchanged during polishing. By measuring thickness changes relative to this stable reference, the polishing amount on the processed surface can be accurately determined even during simultaneous double-sided polishing.
Solution Approach 2:
The substrate thickness is measured before polishing begins, establishing a baseline reference. This preliminary measurement enables subsequent calculation of polishing amounts by comparing pre- and post-polishing thickness values at corresponding positions.
3Manufacturing precision
If heat treatment is performed to simultaneously grow crystal on one surface and etch the other surface, then manufacturing precision is improved, but there is no established method for measuring the etching amount
Solution Approach 1:
The patent implements a feedback measurement system where substrate thickness is measured before and after heat treatment, and growth layer thickness is measured on the grown surface. These measurements feed into calculations that determine the etching amount, providing closed-loop control for process optimization.
Solution Approach 2:
The patent applies different measurement approaches to different surfaces: thickness measurement for the etched surface and growth layer thickness measurement for the grown surface. This localized measurement strategy accounts for the different physical changes occurring on each surface during heat treatment.
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 accurate and non-destructive measurement of etching amounts across the entire surface of semiconductor substrates, ensuring uniformity and quality control, especially for larger substrates, by calculating etching amounts based on positional thickness information.
Implementation Method 1
a growth layer thickness measuring step of measuring a thickness of a growth layer whose crystal has been grown by the heat treatment
Implementation Method 2
a growth layer thickness measuring step of measuring a thickness of a growth layer whose crystal has been grown by the heat treatment
Implementation Method 3
a heat treatment step of, by the heat treatment, forming the growth layer on one surface of the semiconductor substrate and etching another surface thereof
Implementation Method 4
a heat treatment step of, by the heat treatment, forming the growth layer on one surface of the semiconductor substrate and etching another surface thereof
Data Source
AI summary
The present invention addresses the problem of providing a novel technology for measuring an etching amount in heat treatment in which growth and etching proceed simultaneously. The present invention includes: a first substrate thickness measuring step S10 for measuring the thickness 10D of a to-be-heat-treated semiconductor substrate 10; a second substrate thickness measuring step S20 for measuring the thickness 20D of a heat-treated semiconductor substrate 20; a growth layer thickness measuring step S30 for measuring the thickness 21D of a growth layer 21 which has gone through crystal growth by heat treatment; and an etching amount calculating step S40 for calculating the etching amount ED on the basis of the thickness 10D of the to-be-heat-treated semiconductor substrate 10, the thickness 20D of the heat-treated semiconductor substrate 20, and the thickness 21D of the growth layer 21.