Thin-Film Piezo MEMS Foundry

In addition to conducting R&D for many years, ROHM is focused on technological innovation using ferroelectrics. ROHM's thin-film piezo MEMS foundry utilizes in-house high reliability production equipment leveraging market-proven ferroelectric expertise along with a heterogeneous material management system that makes it possible to integrate thin-film piezoelectric MEMS and IC microfabrication technologies. At the same time, joint development allows customers to achieve next-generation solutions featuring breakthrough miniaturization with unprecedented energy savings and performance.

What is ‘piezo’? What is MEMS? -Electronic Basics
Here we explain the basics, characteristics, applications, structures, and properties of piezo and MEMS.

 

Development / Production Contracting

Main Technologies and Services

We provide comprehensive support from prototyping and development to mass production, including process planning for MEMS devices using silicon and SOI wafers, manufacturing high-performance piezoelectric films, and subcontracting and design support for piezoelectric MEMS devices. Feel free to contact us to discuss individual processes not listed on our website or catalogs.

Thin-Film Piezo Technologies

Thin-Film Piezo Technologies
  • ・Sol-gel PZT
  • ・PZT Doping
  • ・Crystallinity Control, etc.

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Semiconductor Process Technologies

Semiconductor Process Technologies
  • ・Lithography
  • ・Etching
  • ・Sputtering, etc.

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MEMS Process Technologies

MEMS Process Technologies
  • ・Wafer-Level Bonding
  • ・Silicon Deep Etching
  • ・ALD Film Deposition
  • ・Dicing, etc.

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Thin Wafer Handling Technologies

Thin Wafer Handling Technologies
  • ・Support Wafer Process
  • ・Special Cleaning
  • ・Laminate, etc.

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Main Technologies and Services

Mass Production and Development Line

A 6-inch MEMS line is being built at LAPIS Semiconductor’s Miyazaki Plant that integrates proprietary thin-film piezo technologies into an LSI production line.

Mass Production and Development Line

Mass Production and Development Line

Location Kiyotake-cho, Miyazaki City, Miyazaki Prefecture, Japan
Clean Room 1,360m2 dedicated to Piezo MEMS
Clean Rating Class 1-1,000
Wafer Diameter 6-Inch
Services Provided Engineering samples, mass-production
ISO Certifications ISO9001, ISO14001
Development / Production Experience Actuators, sensors
Process Technologies PZT piezo thin film, double-sided Si processing, wafer-to-wafer bonding

Flow from Customer Consultation to Mass Production

Our foundry with dedicated MEMS line allows us to handle everything from prototyping to mass production of customer products.

Flow from Customer Consultation to Mass Production

*The above flow is just an example. The actual flow will be determined after consultation in each case.
For inquiries, requests, and/or consultation, please feel free to fill out the form on the contact page.

In-House Equipment

By installing the necessary equipment and analysis tools for MEMS processes in our manufacturing line, we can propose processes for a wide range of devices and initiatives to improve quality.

Process Category Equipment
Deposition
Sol-gel (PZT)
PE-CVD (SiO2, SiN)
LP-CVD (SiO2, SiN, poly-Si)
Thermal Oxide Furnace
Sputter (Pt, Ir, IrO2, AlCu, Ti, TiN, etc.)
ALD(Atomic Layer Deposition)
(Al2O3, SiO2, Ta2O5)
Water-Repellent Coating Formation
Photolithography
Resist Coating / Development
MPA (Mirror Projection Aligner)
Double-Sided Aligner, IR Stepper, i-Line Stepper
Dry Etching
Si Deep Etching
Isolation Layer RIE Equipment
PZT / Electrode ICP Etcher
Wet Etching
SiO2 Etching
Au Etching
Si Anisotropic Etching
Wafer Bonding
Resin Bonding
Anodic Bonding
Process Category Equipment
Tape Lamination
Automated Wafer Tape Bonding Machine
(UV Tape, Thermal Release Sheet, Polyimide, etc.)
Stripping and Cleaning
Asher
Organic / Polymer Stripper
Acid Cleaning, Scrubber
Dividing, etc.
Dicing, Two-Fluid Cleaning
Circle-Cut Dicer
Measurement
Analysis / Measurement SEM, Ion Milling
Optical Measurement Equipment
Front / Back Misalignment Measurement Equipment
Visible Light / IR / Laser Microscopes
X-Ray Diffractometer
Laser Displacement Measuring Device
X-Ray Fluorescence (XRF) Analyzer
Needle / Optical Interference Type Step Gauges
Ellipsometer
Automated Visual Inspection Equipment (Compatible with Front/Back Through-Wafers)
Electrical Characteristics Evaluation Devices
(i.e. Probes, Testers)

In-House Equipment

Examples of Prototypes / Mass Production Results

Leveraging experience in mass-producing inkjet heads along with expertise in MEMS technology allows us to collaboratively develop and evaluate prototype actuator devices requiring low power consumption and high displacement in a compact size.

Examples of Prototypes / Mass Production Results

Examples of Prototypes / Mass Production Results

Process Technology Examples

PZT Film Performance
[PZT Stack Cross-Section]

In 1998 ROHM was the first in the world to successfully mass produce ferroelectric memory.
We also possess many years of experience and expertise in the use of thin-film on silicon wafers.
The result is a sol-gel PZT film (deposited using in-house equipment) that achieves industry-leading piezoelectric performance and reliability.

Parameter Value Conditions
Piezoelectric Constant e31, f (−C/N) 19 10V/μm
Inverse Piezoelectric Constant d31 (−pm/V) 260 10V/μm
Isolation Voltage (V/μm) >75 Room temperature
(Restricted due to evaluation power supply)
Isolation Life (years) >10 20V/μm, 105˚C,
(Estimation via acceleration testing)
Repeat Life (times) >1x1010 10V/um, displacement reduced 10%
(Unipolar pulse)
Leakage Current Density (A/cm2) <1x10−7 20V/μm
 
Wafer-Level Bonding Technology
[Wafer Bonding Cross-Section]

Wafer Bonding Cross-Section / Step Region
[Wafer Bonding Cross-Section / Step Region]

Multiple silicon wafer bonding technologies allow us to perform wafer-level bonding even for devices with complex structures.
*We can propose adhesive application and bonding processes.

Wafer-Level Bonding Technology

Si Deep Etching
[400μm Si Penetration]

Si Deep Etching
[Silicon Wafer Processing]

We utilize multiple Si deep etching equipment from different companies (including some developed in-house) to propose the optimal Si etching process (shape, tolerance, foreign particle level, cost) for each product.

Si Deep Etching

Thin Wafer Handling Technologies
[Thin Silicon Wafer]

We developed in-house wafer transport equipment that enables processing and wafer bonding using thin silicon wafers.

Thin Wafer Handling Technologies

TAIKO Ground Wafer
[TAIKO Ground Wafer]

Thin Wafer Handling Technologies

ALD Protective Film Formation
[Silicon Shaped Cross-Section]

ALD* can form a uniform protective film even on devices with complex uneven shapes.
*ALD:Atomic Layer Deposition

Protective Film: Protects devices from external factors (i.e. ink, abrasion caused by contact, static electricity).

Click here for a detailed explanation of ALD -Electronic Basics

Simulation Analysis of Piezoelectric Devices

Simulation Analysis of Piezoelectric Devices
[Silicon Cantilever Cross-Section]

We can perform finite element simulations of piezoelectric devices to propose optimal structures and processes.

Simulation Analysis of Piezoelectric Devices

FAQ

Q. What is the compatible wafer size and standard?
A. The 6-inch JEITA standard (orientation flat length 47.5mm).
Q. Is it possible to process SOI wafers?
A. Yes, it is possible.
Q. Is it possible to deposit PZT by sputtering?
A. Unfortunately, at this time sputter deposition is not supported.
Q. Is it possible to deposit PZT using the specified Sol-gel solution?
A. Consultation is required.
Q. What range of PZT film thicknesses are possible?
A. We have a proven record in the range of 200nm to 5μm, but a 2μm thickness is standard when considering costs .
Q. What can be done at pre-inspection?
A. Electrical characteristics evaluation (i.e. capacitance, hysteresis, leakage, resistance), external visual inspection (automated), and other processes are available.
Q. Is it possible to request only a prototype?
A. As a general rule, we prioritize projects that have the potential to be mass produced.
Q. Is it possible to perform specific processes?
A. Generally, we do not undertake partial processes for mass production, but are open to negotiation.
Q. Is it possible to produce masks?
A. Yes, it is possible.
Q. What data format is required for mask production?
A. Please provide the data in GDS format.
Q. Is an NDA or development contract necessary?
A. Yes, based on the development STEP.
Q. Is it possible to visit a factory upon request?
A. Yes, it is possible. We can allow visits, depending on the request.
Q. Is it possible to perform processing not available at your facility?
A. Yes, outsourced and offsite equipment are available.