Semiconductor Body Thinning via Field Stop Zones

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Solution Overview

Problem

Existing semiconductor device manufacturing processes face challenges in achieving accurate and reproducible thickness adjustment across the entire semiconductor body, which is crucial for maintaining reliable electrical properties and reducing yield losses, especially in applications like smart cards and vertical power semiconductor components.

Innovation Solution

A method involving impurity implantation and the formation of field stop zones within the semiconductor body, combined with electrochemical etching or alkaline etching to precisely remove the semiconductor body up to the pn junction, allowing for controlled thickness adjustment and reduced thickness fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If conventional thickness adjustment methods are used, then thickness reduction is achieved, but manufacturing precision and reproducibility deteriorate

Engineering Contradiction:

Improvethickness of semiconductor bodyVSAvoidthickness control accuracy

Core Design Contradiction:

Length of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by forming field stop zones with specific dopant concentrations before the thickness adjustment process. These pre-formed zones serve as reference markers that enable subsequent precise etching to the desired thickness. The field stop zones are created at defined depths and concentrations, establishing a foundation for reproducible thinning operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by systematically varying dopant concentrations and depths of field stop zones to achieve precise thickness control. By adjusting parameters such as dopant concentration (e.g., 1e16 to 1e19 atoms/cm³), depth positions, and spatial distributions, the method enables accurate and reproducible thickness adjustment across the semiconductor body surface.

Inventive Principle:

Principle #35Parameter changes

2Length of stationary object

If thickness is reduced for low weight and low height, then device size is improved, but electrical properties reliability deteriorates

Engineering Contradiction:

Improvetotal thickness of semiconductor deviceVSAvoidelectrical properties reliability

Core Design Contradiction:

Length of stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by creating field stop zones with specific dopant concentrations at particular locations and depths within the semiconductor body. These localized doped regions maintain electrical field control and carrier behavior even as the overall device thickness is reduced. The local dopant structures ensure that critical electrical properties remain reliable despite global thinning.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If accurate thickness adjustment is implemented, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvethickness adjustment accuracyVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies self-service by designing field stop zones that automatically serve as etch stop references during the thickness adjustment process. The pre-formed dopant zones with specific concentrations and depths provide inherent guidance for the etching process, enabling the structure to self-regulate the thinning operation without requiring complex external control systems or multiple measurement steps.

Inventive Principle:

Principle #25Self-service

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 approach enables reproducible thinning of semiconductor devices, improving electrical properties and reducing yield losses by ensuring precise thickness control and minimizing thickness variations, thus enhancing the reliability and performance of semiconductor devices.

Implementation Method 1

implanting impurities into a semiconductor body on a first side of the semiconductor body

Methodology Applied

Scientific EffectIon Implantation: Ion Implantation

Implementation Method 2

electrochemical etching or alkaline etching to precisely remove the semiconductor body up to the pn junction

Methodology Applied

Scientific EffectElectrochemical Etching: Electrolysis

Implementation Method 3

electrochemical etching or alkaline etching to precisely remove the semiconductor body up to the pn junction

Methodology Applied

Scientific EffectChemical Etching: Chemical Bonding

Data Source

PatentUS9613804B2Method of manufacturing semiconductor devices which allows reproducible thinning of a semiconductor body of the semiconductor devices

Publication Date: 2017.04.04 INFINEON TECH AUSTRIA AG

AI summary

One embodiment describes a method of manufacturing a semiconductor device. Here, impurities are implanted into a semiconductor body via a first side of the semiconductor body. Thereafter, a drift zone layer on the first side of the semiconductor body is formed. The following is an ablation of the semiconductor body from a second side of the semiconductor body and up to pn junction defined by impurities.