Silicon Epitaxy Process with Denuding Anneal Against BMD Defects
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Solution Overview
Problem
Existing methods for manufacturing semiconductor integrated circuit chips in BCD technology face challenges such as the formation of bulk microdefects (BMDs) due to thermal treatments, which can lead to dislocations and malfunctions in the chips.
Innovation Solution
A method involving a denuding thermal treatment at temperatures higher than or equal to 1,000°C for several hours before forming an epitaxial layer, which reduces interstitial oxygen concentrations and prevents BMD formation in the upper substrate layer, thereby minimizing dislocations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermal treatment is applied at temperatures between 600°C to 900°C, then manufacturing process is simplified, but bulk microdefects form causing dislocations and chip malfunctions
Solution Approach 1:
A denuding thermal treatment is applied before the main thermal treatment to remove interstitial oxygen from the substrate. This preliminary action prevents the formation of bulk microdefects during subsequent thermal processing, allowing simplified manufacturing without compromising chip reliability.
Solution Approach 2:
The denuding treatment creates a denuded zone that counteracts the harmful effect of interstitial oxygen accumulation. By removing oxygen beforehand, the treatment prevents the harmful formation of BMDs and dislocations that would otherwise occur during standard thermal processing.
2Reliability
If high temperature denuding treatment (≥1,000°C) is applied for several hours, then BMD density is reduced significantly, but processing time and energy consumption increase
Solution Approach 1:
The patent optimizes the denuding treatment parameters by applying high temperature (≥1,000°C) for a specific duration (several hours) to achieve effective oxygen removal. This parameter optimization ensures sufficient BMD density reduction while minimizing unnecessary processing time and energy consumption.
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
The method effectively creates a denuded zone with reduced BMD density, enhancing the structural integrity of the semiconductor chip and reducing the likelihood of dislocations and associated malfunctions.
Implementation Method 1
applying to the substrate a denuding thermal treatment which removes interstitial oxygen from the substrate through diffusion
Implementation Method 2
forming by epitaxy, on top of and in contact with the upper surface of the substrate, a doped single-crystal silicon layer
Data Source
AI summary
A substrate made of doped single-crystal silicon has an upper surface. A doped single-crystal silicon layer is formed by epitaxy on top of and in contact with the upper surface of the substrate. Either before or after forming the doped single-crystal silicon layer, and before any other thermal treatment step at a temperature in the range from 600° C. to 900° C., a denuding thermal treatment is applied to the substrate for several hours. This denuding thermal treatment is at a temperature higher than or equal to 1,000° C.