BAW Structure With Aluminum Copper Nitride for Single-Chamber Deposition

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Solution Overview

Problem

Conventional bulk acoustic wave (BAW) structures require separate process chambers for forming piezoelectric layers and aluminum copper metallization, leading to reduced manufacturing efficiency and increased costs.

Innovation Solution

A bulk acoustic wave structure utilizing an aluminum copper nitride piezoelectric layer, which can be formed in the same process chamber as the aluminum copper metallization, eliminating the need for additional chambers and enhancing manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If separate process chambers are used for forming piezoelectric layers and aluminum copper metallization, then manufacturing precision and material quality are maintained, but manufacturing efficiency decreases and costs increase

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidprocess chamber quantity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the formation of piezoelectric layers and aluminum copper metallization into a single process chamber, eliminating the need for separate chambers. This merging of previously distinct processes allows both piezoelectric material deposition and aluminum copper metallization to occur in the same equipment, thereby improving manufacturing efficiency and reducing overall process complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The process chamber is designed to perform multiple functions: it can deposit piezoelectric layers, form aluminum copper metallization, and create bond pads and interconnect structures. This multi-functional capability allows a single chamber to replace what previously required multiple specialized chambers, directly addressing the contradiction between productivity and device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If a single process chamber is used for both piezoelectric layer and aluminum copper metallization, then manufacturing efficiency and cost are improved, but process contamination risk increases

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidprocess contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The process chamber incorporates separate deposition zones or regions that allow distinct processes (piezoelectric layer formation and aluminum copper metallization) to occur simultaneously or sequentially without cross-contamination. This spatial segmentation within the single chamber maintains material purity while achieving the benefits of consolidated processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses intermediate layers or barrier structures that prevent direct interaction between piezoelectric materials and aluminum copper metallization. These intermediary elements act as protective interfaces, allowing both materials to be processed in the same chamber while preventing harmful contamination between the different material systems.

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 approach allows for the formation of BAW structures with equivalent resonator performance to conventional structures while reducing manufacturing costs and increasing efficiency by using a single process chamber for both piezoelectric layer and metallization deposition.

Implementation Method 1

When an electric field is applied across the piezoelectric layer via the upper and lower electrodes, electrical energy is converted into acoustic energy in the piezoelectric layer through electromechanical coupling, thereby causing the piezoelectric layer to vibrate and generated acoustic waves

Methodology Applied

Scientific EffectElectromechanical coupling: Piezoelectric Effect

Implementation Method 2

The acoustic mirror, which can include a number of alternating dielectric and metal layers, can be used to trap acoustic energy in the piezoelectric layer by reflecting acoustic energy, thereby preventing acoustic energy loss through transmission into the substrate

Methodology Applied

Scientific EffectAcoustic reflection: Reflection

Implementation Method 3

A BAW structure with an aluminum copper nitride piezoelectric layer is formed using a single process chamber, allowing for the deposition of both the piezoelectric layer and aluminum copper metallization

Methodology Applied

Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentUS8601655B2Process of making a bulk acoustic wave structure with an aluminum copper nitride piezoelectric layer

Publication Date: 2013.12.10 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

According to an exemplary embodiment, a bulk acoustic wave structure includes a lower electrode situated over a substrate. The bulk acoustic wave structure further includes a piezoelectric layer situated over the lower electrode, where the piezoelectric layer comprises aluminum copper nitride. The bulk acoustic wave structure further includes an upper electrode situated over the lower electrode. The bulk acoustic wave structure can further include a bond pad connected to the upper electrode, where the bond pad comprises aluminum copper. The lower electrode can include a high density metal situated adjacent to the piezoelectric layer and a high conductivity metal layer underlying the high density metal layer.