Semiconductor Substrate Metal Contamination Detection via Oxide Film
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Solution Overview
Problem
Conventional photoluminescence (PL) evaluation methods for semiconductor substrates face challenges in accurately detecting metal contamination and its degree due to surface recombination loss from external contamination and high light intensity issues, especially in heavily doped substrates.
Innovation Solution
A semiconductor substrate manufacturing method involving controlled metal contamination with Fe, Cu, or Ni, followed by dry oxidation to form an oxide film, and subsequent evaluation using PL and u-PCD methods to assess contamination levels, allowing for accurate detection of metal contamination in both surface and bulk layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PL evaluation method is used, then evaluation process is simple, but measurement precision deteriorates due to surface recombination loss and high light intensity in heavily doped substrates
Solution Approach 1:
An oxide film is formed on the semiconductor substrate surface before PL evaluation to prevent surface recombination loss. This preliminary treatment eliminates the harmful surface effects that degrade measurement precision, allowing accurate detection of metal contamination without requiring complex post-processing or multiple evaluation steps.
Solution Approach 2:
An oxide film is introduced as an intermediary layer between the semiconductor substrate surface and the external environment. This film acts as a protective barrier that eliminates surface recombination loss while allowing the PL evaluation to proceed with standard equipment, thus improving measurement precision without significantly increasing process complexity.
2Measurement precision
If semiconductor substrate is heavily doped, then electrical properties are improved, but measurement precision deteriorates due to high light intensity making metal contamination undetectable
Solution Approach 1:
An oxide film is formed on the semiconductor substrate surface before PL evaluation to prevent surface recombination loss. This preliminary treatment eliminates the harmful surface effects that degrade measurement precision, allowing accurate detection of metal contamination without requiring complex post-processing or multiple evaluation steps.
3Measurement precision
If surface recombination loss occurs, then evaluation time is reduced, but measurement precision deteriorates making it impossible to accurately evaluate metal contamination
Solution Approach 1:
An oxide film is formed on the semiconductor substrate surface before PL evaluation to prevent surface recombination loss. This preliminary treatment eliminates the harmful surface effects that degrade measurement precision, allowing accurate detection of metal contamination without requiring complex post-processing or multiple evaluation steps.
Solution Approach 2:
An oxide film is introduced as an intermediary layer between the semiconductor substrate surface and the external environment. This film acts as a protective barrier that eliminates surface recombination loss while allowing the PL evaluation to proceed with standard equipment, thus improving measurement precision without significantly increasing process complexity.
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 method enables precise and easy evaluation of metal contamination in semiconductor substrates, effectively overcoming the limitations of conventional PL evaluation by enhancing detection sensitivity and accuracy for both lightly and heavily doped substrates.
Implementation Method 1
forcibly forming an oxide film on the surface of the semiconductor substrate
Implementation Method 2
light generated when electron/hole pairs, excited by the excitation light, are recombined is detected
Data Source
AI summary
A semiconductor substrate manufacturing method according to an embodiment comprises the steps of: contaminating at least one of a surface layer of a doped semiconductor substrate having a specific resistance of less than 0.1 Ω·cm and a bulk layer below the surface layer with at least one metal of Fe, Cu, and Ni; performing dry oxidation at 950° C. for 30 minutes to forcibly form an oxide film on the surface of the semiconductor substrate; and assessing at least one of the presence and the degree of contamination of metal contained in at least one of the oxide film-formed surface layer and bulk layer by using a photoluminescence assessment method.