Growing Demand of Gas Sensors
Gas sensors detect flammable gas, toxic gases, alcohol, etc. In recent years, in order to achieve sustainable development goals, the application of gas sensors has diversified with activity to reduce emission of CO₂ which is cause of global warming, and stricter regulations on air quality in the workplace. In manufacturing sites, demand for CO₂ sensors is increasing for CO₂ monitoring. Similarly, attention of air quality indoors and outdoors is increasing, and there are needs for monitoring air quality in various locations. Ex; BEMS (Building Energy Management System)
Outdoors
Vehicles
Offices
Buildings
NDIR Gas Sensors for CO₂ Sensing
NDIR (Non-Dispersive InfraRed) gas sensors which use a IR light source is mainly used to detect CO₂. From above background, the demand for NDIR gas sensors is expected to increase. Kyocera offers new “Ceramic Package” solutions for NDIR gas sensors.
New Packaging Solution for NDIR Gas Sensors
“Ceramic Package” which can be used for IR emitters / Photodiodes
For NDIR gas sensors, IR emitters for the IR light source and photodiode for receiving IR are required. The two types of NDIR gas sensor are shown as below.
Contrast Type
Reflection Type
Ceramic Packaging for IR Emitters
LED and MEMS micro-heaters etc. are used in IR emitters. By replacing the TO-CAN package with a ceramic package, smaller and thinner package design is possible by surface mounting without lead or pin.
Packaging for IR emitter
Ceramic Packages for Photodiodes
Photodiodes, thermistors, thermopiles and pyroelectric sensors are used for photo detector.
Using a ceramic package allows for hermetic and/or vacuum sealing solutions which are challenging for organic package solutions.
Therefore, sensitivity improvement can be expected by using a ceramic package.
Moreover, since ceramic packages can easily realize 3D structure by lamination,
it is easy to form cavities which optical filters can be put on, and it is also possible to attach two photodiodes for CO2 detection and reference in one package for dual wavelength detection method.
One Package for
Dual Wavelength Detection
Additionally, ceramic package characteristics include less out gassing, higher heat dissipation, and higher heat resistance, allowing ceramic package solutions to keep higher sensing accuracy even in a harsh environment, such as vehicle applications.
Kyocera has product lineup for optical lid
Features of Ceramic Packages
for Gas Sensors
1<Sealing Technology>
- Seal with glass, silicon and germanium etc.
- Hermatically sealing
- Vacuum sealing
2<Flexible Cavity Design>
- Protects chip and wire by cavity
- Improves assemble reliability by W/B shelf
3<Ceramic package>
- High durability
- High heat resistance
- Less out gas
- Similar CTE to Silicon
4<2nd Assembly>
- Surface mounting / Reflow process
- Side metallization
Improves assembly reliability by solder fillet
Comparison of Ceramic Packages
and Other Materials
Comparison with Metal CAN Packages
Miniaturization and thinner by switching to a ceramic package
Metal CAN Package
Ceramic Package
From pin insertion assembly to reflow surface assembly
Smaller and thinner package designs by 3D pattern routing
Design proposal by customized package
Comparison with Organic Packages
Less out gas than organic packages
Ceramic has less out gas (ex. CO₂) than organic material in high-temperature environments. Therefore, ceramic packages are more useful for improving the accuracy of gas sensing.
Out Gas Comparison with Organic Package
*Analysis method : Continuous temperature rising GC-MS(60~310℃)
Out Gas from Organic Packages
Out Gas from Ceramic Packages
*Analysis was conducted by Kyocera
Ceramic packages is possible to make the gas sensor smaller and thinner. Moreover, ceramic package has less out gas under high-temperature environments, high heat resistance, high rigidity, and close CTE to Si, which improves mounting reliability. Therefore, ceramic package will be suitable option for high reliability applications.
Sealing Options
for Ceramic Packages
| Sealing method | Glass (Frit) |
Resin (Epoxy) |
AuSn / Solder |
Seam weld | |
|---|---|---|---|---|---|
| LID Material |
Ceramic | ||||
| Metal | |||||
| Sealing Temp. |
340℃～ | 120-150℃ | 320℃ | ~200℃ (Chip area) |
|
| Positive Points |
High productivity (Continuous tunnel furnace) |
Low temp. sealing (~150℃) (Low heat stress on chip) |
Low heat stress | Low stress on chip |
|
| Negative Points |
Higher seal. temp. Pb included Frit |
Low-productivity Non-hermetic (Moisture permeation) |
Higher seal. temp. Pb including solder |
Low productivity High seal. stress |
|
| Note | Pb free Frit is available (Seal temp. 460℃) |
Glass lid / Si lid is available B stage(Semi-cured) epoxy is applied for epoxy LID |
AuSn vacuum seal. is available |
Vacuum seal. is available |
|
| Structure PKG/LID (Ex.) |
|
|
|
|
|
*Kyocera proposes a suitable sealing method based on customer requirements.
There are open tool products which are suitable for each of the above sealing methods.
Flexible Shipping Form
for Various Assembly Methods
Singulated Shipment
Singulated package is mounted on plastic tray
MAT Shipment®
※MAT：Metal frame
with Adhesive Tape
Singulated package is mounted on adhesive tape.
Metal frame material : SUS
*MAT shipment is registered trademark of Kyocera corporation
Array Shipment
Array with V-cut (snap line)
Array with V cut (snap)
⇒Singulation is easily realized
after assembly process
Flexible shipping option can be offered.
Please kindly consult us if there is request for shipping form.
Ceramic Package is Usable
for Various Types of Gas Sensors
Metal Oxide
Gas Sensors
According to the trend of MEMS chip-based gas sensor, packaging has been shifted from TO-CAN to SMD type.
Multi-layer ceramic package which has 3D pattern rooting can support development of smaller and thinner gas sensor.
Electrochemical
Gas Sensors
Electrochemical gas sensor is based on chemical reaction principle and used for high accuracy application for CO, NOx
gas and so on.
Alumina, which is a ceramic material, has strong chemical resistance and less chemical reaction to acid and alkaline
solutions. Therefore, ceramic packages are usable for electrochemical gas sensors.
Other
Gas Sensors
Ceramic packages can be used for various type of gas sensors, such as hydrogen, oxygen, smell sensor and so on. With open tool product lineup, it is possible to conduct evaluation without tooling cost.
Send open tool drawing /
Generate custom drawing /
Submit quotation
Please feel free to contact us.