Semiconductor Sensor Pt-W Interconnect TiO2 Barrier

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing semiconductor sensors face challenges in maintaining stability and performance at high temperatures due to diffusion issues between platinum (Pt) and tungsten (W) layers, affecting the reliability and efficiency of gas-sensing devices.

Innovation Solution

The proposed semiconductor sensor incorporates an interconnect structure with a platinum layer directly contacting a tungsten layer, along with a TiO2 layer as a barrier, which improves stability and prevents diffusion between Pt and W, enhancing the sensor's performance and compatibility with current fabrication processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a platinum layer is directly formed on a tungsten layer to create an interconnect structure, then electrical connectivity is achieved, but diffusion between Pt and W occurs at high temperatures causing instability

Engineering Contradiction:

Improvestability of interconnect structureVSAvoidcompositional stability of Pt-W interface

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

A TiO2 barrier layer is introduced between the platinum layer and tungsten layer to prevent direct contact and diffusion between Pt and W atoms at high temperatures. The TiO2 layer acts as an intermediary that maintains electrical connectivity while blocking atomic diffusion, thereby resolving the contradiction between achieving electrical connectivity and maintaining compositional stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If a TiO2 barrier layer is introduced between Pt and W to prevent diffusion, then compositional stability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvecompositional stability of Pt-W interfaceVSAvoidstructural complexity of interconnect

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The TiO2 barrier layer is formed by oxidizing a titanium layer through controlled thermal oxidation or chemical vapor deposition processes. By changing the chemical state of titanium from metallic Ti to oxidized TiO2, the material gains diffusion barrier properties while maintaining compatibility with existing semiconductor fabrication processes, thus improving compositional stability without significantly increasing manufacturing complexity.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If the sensor operates at high temperatures (1500-4500K) to detect gas concentrations, then sensing performance is improved, but diffusion between metal layers accelerates causing reliability issues

Engineering Contradiction:

Improvegas concentration detection accuracyVSAvoidstability of sensor structure

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The TiO2 barrier layer serves as a thermal and diffusion barrier that allows the sensor to operate at high temperatures (1500-4500K) for improved gas detection accuracy while preventing accelerated diffusion between Pt and W interconnect layers. The TiO2 layer maintains structural integrity at elevated temperatures, enabling high-performance sensing without compromising reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 configuration significantly enhances the stability and performance of semiconductor sensors at high temperatures, preventing diffusion issues between Pt and W, and is suitable for mass production, ensuring reliable gas-sensing operations.

Implementation Method 1

a TiO2 layer as a barrier, which improves stability and prevents diffusion between Pt and W

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

The interconnect structure includes a tungsten layer buried in the IMD layer, wherein part of a top surface of the tungsten layer is exposed by at least a via. The interconnect structure further includes a platinum layer formed in said at least the via, and a TiO2 layer formed on the IMD layer adjacent to said at least the via. The platinum layer is directly formed on the TiO2 layer above the IMD layer.

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The second Pt-patterned portion acts as a heater of the gas-sensing device

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11345590B2Semiconductor sensor and method of manufacturing the same

Publication Date: 2022.05.31 UNITED MICROELECTRONICS CORP

AI summary

A semiconductor sensor, comprising a gas-sensing device and an integrated circuit is provided. The gas-sensing device includes a substrate having a sensing area and an interconnection area in the vicinity of the sensing area, an inter-metal dielectric (IMD) layer formed above the substrate in the sensing area and in the interconnection area, and an interconnect structure formed in the interconnection area; further includes a sensing electrode, a second TiO2-patterned portion, and a second Pt-patterned portion on the second TiO2-patterned portion in the sensing area. The interconnect structure includes a tungsten layer buried in the IMD layer, wherein part of a top surface of the tungsten layer is exposed by at least a via. The interconnect structure further includes a platinum layer formed in said at least the via, a TiO2 layer formed on the IMD layer, a first TiO2-patterned portion and a first Pt-patterned portion.