Thin-Film Piezo MEMS Foundry
ROHM has conducted R&D over many years, focusing on technological innovation using ferroelectrics. ROHM thin-film piezo MEMS foundry utilizes in-house high reliability production equipment leveraging market-proven ferroelectric technology along with a heterogeneous material management system that makes it possible to integrate thin-film piezoelectric MEMS and IC microfabrication technologies. In addition, joint development allows customers to achieve next-generation solutions featuring breakthrough miniaturization with unprecedented energy savings and performance.
- ・Total support is provided, from prototype development to mass production.
- ・As a strategic partner with customers, ROHM supports products from the process and manufacturing aspects.
- ・Achieves superior products utilizing high performance, high reliability thin-film piezo technology.
- R&D ・ Manufacturing Site
- Flow from Customer Consultation to Mass Production
- In-House Equipment
- Process Capabilities
- Prototype Examples
- Process Technology Examples
- Q&A
R&D ・ Manufacturing Site: LAPIS Semiconductor Miyazaki Co.,Ltd.
| Location | Kiyotake-cho, Miyazaki City, Miyazaki Prefecture, Japan |
|---|---|
| Clean Room | 1,360m2 dedicated to Piezo MEMS (of 6,000m2 total M2 fab.) |
| 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, bulk/surface MEMS, double-sided Si processing, wafer-to-wafer bonding |
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 by clicking on the button below
In-House Equipment
| Process Category | Equipment |
|---|---|
| Photolithography | Resist Coating / Development |
| MPA (Mirror Projection Aligner) | |
| Double-Sided Aligner | |
| i-Line Stepper | |
| Tape Lamination | Laminators (UV Tape, Thermal Release Sheet, PI Film, etc.) |
| Deposition | Sol-Gel (PZT System) |
| PE-CVD (SiO2, SiN) | |
| LP-CVD (SiO2, SiN, poly-Si) | |
| Furnace (Thermal Oxide) | |
| Sputter (Al System, Au, Ti, TiN, TiW, Pt, Ir, etc) | |
| ALD (Atomic Layer Deposition) (Al2O3, SiO2, Ta2O5) | |
| Water-Repellent Coating Formation | |
| Dry Etching | Si Deep RIE |
| Isolation Layer RIE | |
| PZT/Electrode ICP Etcher | |
| Wet Etching | SiO2 Etching |
| Au Etching | |
| Si Anisotropic Etching | |
| Stripping and Cleaning | Asher |
| Organic/Polymer Stripper | |
| Acid Cleaning | |
| Scrubber | |
| Wafer Bonding | Resin Bonding |
| Anodic Bonding | |
| Dividing, etc. | Dicing, Two-Fluid Cleaning |
| Circle-Cut Dicer | |
| Measurement | Analysis/Dimension Measurement SEM |
| Optical Dimension Measurement Equipment | |
| Front/Back Misalignment Measurement Equipment | |
| Visible Light/IR/Laser Microscopes | |
| X-Ray Diffractometer | |
| Laser Displacement Measuring Equipment | |
| X-Ray Fluorescence (XRF) Analyzer | |
| Needle/Optical Interference Type Step Gauges | |
| Ellipsometer | |
| Appearance Inspection Equipment | |
| Electrical Characteristics Evaluation Devices (i.e. Probes, Testers) |
Process Capabilities
| Process | Process Specifications | Remarks |
|---|---|---|
| Photolithography | Minimum line width: 1mm (Stepper) Minimum line width: 3mm (Aligner) |
|
| Si Deep RIE | Taper angle: 90 +/- 1deg Etching rate in-plane uniformity: <5% Dimensional accuracy: ±0.1μm (Both are pattern-dependent) |
Substrate through hole processing possible Both sides can be processed (Notch-free) Taper control possible |
| TMAH Etching | Within 5% in-plane with respect to depth | Substrate through hole processing possible Both sides can be processed |
| PZT Deposition | Film thickness accuracy: In wafer: ±1.0% Between wafers/lots: ±2.5% |
Doping ex. (Nb, La) |
| PZT Etching | Processing line width accuracy: ±1μm Etching rate in-plane uniformity: <5% (PZT thickness ~3μm, tapered shape available) |
Pt stop enabled |
| Sputter | Thickness uniformity: <4% in-plane | AlCu, Au, Ti, TiN, TiW, Pt, Ir |
| CVD | Thickness uniformity: <4% in-plane | SiO2, SiN |
| ALD | Thickness uniformity: <5% in-plane | Al2O3, Ta2O5, SiO2 |
| Resin Bonding | Alignment accuracy: ±5μm Resin thickness: 1 to 3μm |
Epoxy, BCB |
| Anodic Bonding | Internal seal pressure: >0.01Pa | Si/glass |
Prototype Examples
- Inkjet actuators
- Inkjet fluidics, nozzles
- MEMS mirrors
- MEMS microphones
- Piezo MEMS speakers
- Micro pumps
- RF elements
- Pyroelectric sensors
- Ultrasonic sensors
- Accelerometers
- Gyro sensors
- Pressure sensors
Process Technology Examples
PZT Film Performance
In 1998 ROHM became the first in the world to successfully mass produce ferroelectric memory by leveraging many years of
experience and expertise in utilizing PZT thin film for Si wafer processes.
Developed using in-house equipment, ROHM’s sol-gel PZT film features industry-leading performance and reliability.
| Parameter | Value | Conditions |
|---|---|---|
| Effective Piezoelectric coefficients e31, f (-C/N) | 19 | 10V/μm |
| Piezoelectric coefficients d31 (-pm/V) | 260 | 10V/μm |
| Breakdown Voltage (V/μm) | >75 | Room temperature, (Restricted due to evaluation power supply) |
| Breakdown Life (years) | >10 | 20V/μm, 105℃, (Estimation via acceleration testing) |
| Fatigue Life (times) | >1x1010 | 10V/μm, displacement reduced 10% (Unipolar pulse) |
| Leakage Current Density: (A/ cm2) | <1x10-7 | 20V/μm |
Si Deep RIE
Several Si deep etching equipment from different companies (along with some developed in-house) allow ROHM to propose the optimal Si etching process (shape, tolerance, foreign particle level, cost) for each product.
Tapered etching is also possible.
Thin Wafer Handling Technology
ROHM developed original wafer transport equipment that enables process and wafer bonding of thin Si wafers.
Q&A
- 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 5um, but a 2um 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.