Semiconductor Substrate Temperature Measurement Using Junction Capacitor Resonance

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Solution Overview

Problem

Existing methods for determining the temperature of semiconductor substrates during processing, such as thermocouples and infrared techniques, are not accurate enough due to variable thermal contact and non-reproducible conditions, leading to irreproducible temperature determination and inadequate control.

Innovation Solution

A resonance circuit comprising a junction capacitor and an inductor is provided on the semiconductor substrate, irradiated with electromagnetic energy to determine the resonance frequency, which is sensitive to temperature changes, allowing for more accurate temperature determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If thermocouples are used to determine the temperature of the semiconductor substrate, then temperature determination is possible, but the accuracy is insufficient due to variable thermal contact quality

Engineering Contradiction:

Improvetemperature determination accuracyVSAvoidreproducibility of temperature determination

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical thermal contact system (thermocouple physically touching the substrate) with an electromagnetic field-based measurement system. The resonance circuit is excited by an electromagnetic field from the radiation device, and the resonance frequency is detected through electromagnetic coupling, eliminating the need for direct mechanical contact and its associated variability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a resonance circuit as an intermediary element between the measurement system and the substrate. This resonance circuit, formed by conductive patterns on the substrate, serves as a mediator that translates temperature information into measurable resonance frequency changes without requiring direct contact between the thermocouple and substrate.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a resonance circuit with a dielectric capacitor is used to measure substrate temperature, then non-contact measurement is achieved, but the sensitivity to temperature changes is insufficient

Engineering Contradiction:

Improvetemperature determination accuracyVSAvoidsensitivity of capacitance value to temperature

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent changes the capacitor type from a dielectric capacitor to a junction capacitor, exploiting the strong temperature dependence of the junction capacitance in semiconductor pn-junctions. The junction capacitance varies significantly with temperature due to changes in carrier concentration and depletion region width, providing much higher sensitivity compared to dielectric capacitors.

Inventive Principle:

Principle #35Parameter changes

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 provides a significantly improved accuracy in temperature determination, with a sensitivity factor of 30 times higher than dielectric capacitors, ensuring precise temperature control during semiconductor processing.

Implementation Method 1

determining a resonance frequency of the resonance circuit by detecting an effect of the resonance circuit on the electromagnetic field

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 2

irradiating the resonance circuit with electromagnetic energy of an electromagnetic field generated by a radiation device

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the sensitivity of the resonance frequency to the temperature of the semiconductor substrate increases, thereby providing a more accurate determination of the temperature of the semiconductor substrate

Methodology Applied

Scientific EffectThermal effect on semiconductor junction capacitance: Temperature Gradient

Data Source

PatentEP2010880B1Method and device for determining the temperature of a semiconductor substrate

Publication Date: 2009.10.14 NXP BV

Figure 1~2
Figure 3A~3B
Figure 4~5

AI summary

The invention provides a method and a device for determining the temperature of a semiconductor substrate. A resonance circuit (110) is provided on the semiconductor substrate and is formed by a junction capacitor (11) and an inductor (12). The substrate is placed on a holder and the resonance circuit (110) is irradiated with electromagnetic energy of an electromagnetic field (5) generated by a radiation device (200). A resonance frequency of the resonance circuit (110) is determined by detecting an effect of the resonance circuit (110) on the irradiated electromagnetic field (5), and a temperature of the semiconductor substrate is determined as a function of the resonance frequency. The method and device according to the invention provide for a more accurate determination of the temperature of the semiconductor substrate due to an increased sensitivity to the temperature of the junction capacitor (11).