Short Wave Infrared Emitters in a Chip Scale Package (CSP) Introduced by Marktech Optoelectronics – An Industry First

September 1, 2021 – Latham, NY, USA – Marktech Optoelectronics, Inc. (www.marktechopto.com)(Marktech), a privately-held and veteran-owned leading designer and manufacturer of standard and custom optoelectronics, including UV, visible, near-infrared (NIR), and short-wavelength infrared (SWIR) emitters, detectors, InP epi wafers, and other compound semiconductors, today announced the introduction of chip-scale packaged (CSP) short wave infrared emitters (also known as CSP SWIR LEDs, CSP short wave IREDs, or CSP SWIR emitters).

The availability of SWIR LEDs or emitters in a chip-scale packaged form factor is an industry first. The compactness of the new CSP SWIR LEDs is impressive. In fact, a dozen or more of Marktech’s CSP SWIR emitters would fit on the surface of a penny.

CSP SWIR LED Performance Features

These Next-Generation CSP short wave IR emitters have an extremely small footprint compared to conventional short wave IR emitters in surface mount device (SMD) or transistor outline (TO) metal can packages. The new short wave IR emitters consist of a high-performance SWIR chip in an extremely compact 1.6mm x 1.6mm x 1.6 mm cube-shaped SMD package with two lead pads. The flat lens design produces a wide or Lambertian radiation pattern with beam angles of 130°. Marktech’s chip-scale packaged SWIR LEDs are both RoHS and REACH compliant. The high-performance CSP short wave infrared emitter products are available in wavelengths ranging from 1040 to 1650 nm. The specific SWIR LED wavelengths available include:

1020nm and 1720nm CSP short wave IR emitters are available using conventional, lower power output SWIR chips. Marktech Optoelectronics can provide additional engineering and testing to deliver specific wavelengths and forward voltages as well as tighter power output bands through sorting or epi material customization. In machine vision and inspection, SWIR bandpass filters or longpass filters can be used in conjunction with SWIR light sources and SWIR cameras to adjust the bandwidth or pass only the SWIR light required for imaging – thereby increasing SWIR image contrast and resolution.

The major performance attributes of Marktech’s CSP short wave infrared emitters include:

Up to double the power output – High-performance SWIR LED dies in the CSP package provide up to 2X the power output compared to older, conventional SWIR LED chips
Compact CSP LED size enables high stacking density on a printed circuit board (PCB) due to the small 1.6mm X 1.6mm footprint
Improved SWIR component reliability
Increased SWIR component lifetime or mean time between failures (MTBF)
Lower thermal resistance compared to plastic leaded chip frame (PLCC) SMD SWIR LEDs

Reliability increases originate from several facets of the chip-scale packaged SWIR LED design. First, the advanced SWIR die itself contributes to improved reliability.

Second, Marktech’s CSP packaged SWIR LED SMD combines aspects of high power emitter packaging with typical LED chip-scale packaging to create a new high power chip-scale package SMD (HP CSP SMD).

The high-power (HP) SWIR LED packages utilize a low thermal resistance ceramic submount to rapidly dissipate heat. The high thermal resistance in plastic leaded chip carriers (PLCC) SMD LEDs results in poor heat dissipation and reduced performance.

Ceramics are typically 10 times higher in thermal conductivity compared to plastics. The ceramic submount in the Marktech’s CPS SWIR LED provides a powerful “heat slug” for reduced thermal resistance, enhanced heat dissipation, and an overall improvement in reliability. The large contact area of the anode and cathode pads on the bottom of the CSP SWIR SMD package provide lower resistance electrical and thermal conduction paths.

CSP SWIR LED Applications

Short wave infrared emitters have become important components empowering advanced designs in aerospace, automotive, medical, imaging, spectroscopy, microscopy, night vision, security, defense, agriculture, semiconductor, industrial, and communications applications.

Certain materials such as silicon, which are normally opaque in the visible band, are transparent in the SWIR wavelength region. Some materials, biological samples, and organic compounds have enhanced contrast or exhibit fluorescence when imaged in the SWIR band. In medical applications, SWIR imaging systems have been developed to detect cancers, non-invasively measure blood glucose, and diagnose inner ear conditions (otoscopes).

In semiconductor applications, SWIR microscopes and inspection systems more efficiently detect defects on the surface of silicon wafer surfaces. SWIR vision systems and digital sorters utilize the contrast differences between various materials and natural compounds to detect contamination in grains, nuts, seeds, and other food products.

Shadowing is more pronounced under SWIR light and therefore the shape and form of parts and their features are more easily determined, which is useful for machine vision, surface metrology, and optical gaging system applications.

SWIR cameras, SWIR microscopes, SWIR spectrometers, SWIR endoscopes, SWIR hyperspectral machine vision systems require consistent, spatially homogeneousness SWIR light sources with high power output or intensity. The combination of high power output in a denser concentration on a PCB or ring board has the potential to improve image quality, signal-to-noise ratio, and detection efficiency in spectroscopy or chemical analysis, microscopy, imaging, wafer inspection, and vision systems. High uniformity SWIR light source illumination of a surface can be attained at short working distances with denser PCB stacking of Marktech’s compact CSP SWIR LEDs.

SWIR cameras, SWIR detectors, and SWIR LIDAR systems can “see” through obscured environments such as rain, fog, clouds, plastics, and organic materials. Marktech’s SWIR InGasAs detectors in combination with CSP SWIR LEDs can provide compelling advantages in collision avoidance and autonomous vehicle detection applications in the automotive, aerospace, defense, and security industries. Unlike conventional thermal imagers and infrared cameras for night vision, SWIR camera image sensors and SWIR detectors are not overwhelmed or “blinded” by daylight infrared radiation from the sun, which means SWIR cameras and SWIR detectors can be used day and night in surveillance, agricultural crop sensing, and defense applications.

CSP SWIR LED Design Advantages

These new SWIR components are ideal for optoelectronic design projects demanding increased miniaturization or compactness combined with enhanced longevity, dependability, and power output performance.

The potential design benefits of Marktech’s CSP short wave IR emitter technology includes:

Miniaturization – the small footprint and reduced height of CSP SWIR LEDs will allow design engineers to reduce the size of SWIR cameras, SWIR spectrometers, SWIR microscopes, SWIR machine vision systems
Higher Intensity – the ability to use more SWIR LEDs per unit area in combination with the higher power output of each advanced SWIR emitter results in an increase in total power output and intensity.
Improved Uniformity – the use of a larger number of SWIR LEDs across an area should provide a more uniform short wave infrared light source even at closer working distances.
Increased System Reliability – the higher lifetime and reliability of Marktech’s CSP SWIR emitters should contribute to improved system reliability.

For multispectral camera and machine vision applications, combinations of NIR-vis and SWIR broadband LEDs can be packaged to provide light sources custom matched to the spectral response of specific hyperspectral cameras. CSP multispectral LED light sources have the additional advantage of lower operating temperature and power consumption compared to hyperspectral Halogen light sources.

CSP SWIR LED Thermal Management and Board Design

While CSP SWIR LEDs have many performance advantages, chip-scale packaged LED SWIR designs with high packing densities can overcome the heat dissipation ability of FR4 printed circuit board materials. When compared to visible light emitters, SWIR LEDs tend to be less efficient and will generate more heat under the same current or power loads. Printed circuit boards with high stacking densities of SWIR LEDs should have an array of thermal vias or even a thermal pad and additional heat sinks on the underside to help improve the thermal performance. A ceramic or aluminum cored metal clad printed circuit board (Al-cored MCPCB) or a chip-on-board (COB) might be the best choice to maximize heat dissipation. Marktech can provide dense-packed boards populated with SWIR LED emitters on ceramic or aluminum cored PCBs.

Marktech’s engineering experts can provide thermal management analysis and design of your SWIR boards and modules to assure your SWIR LEDs and SWIR detectors stay within operating temperature limits. Thermal management requirements are determined by understanding the interaction of ambient temperature fluctuations, heat generation from the SWIR LED, and heat dissipation characteristics of the assembled PCB or module. If the operating temperature still exceeds the specified limits, then a derating analysis can be performed to determine the reduced lifetime and operating current values.

In addition to advanced optoelectronics packaging, Marktech has a well-established and industry respected capability in both board and module design, thermal management engineering, and testing to validate the optoelectronic performance characteristics of incoming optoelectronic devices as well as the realized designs or finished products.

Marktech’s Advanced Optoelectronic Packaging Family

In addition to advanced SWIR LED emitters, Marktech Optoelectronics has additional infrared emitters within the near IR (NIR) and mid-IR (MIR) bands. Marktech can combine various NIR and SWIR LEDs and detectors within the same package for multispectral applications such as LED LIDAR and optical ranging sensors. Marktech also provides complementary products such as short wave IR InGaAs detectors for applications requiring both a SWIR light source combined with a SWIR sensor.

Marktech’s CSP SWIR LED joins a growing family of advanced emitters and detectors in enhanced packaging such as Marktech’s ATLAS packaged line of LEDs, photodetectors, and emitter-detectors. The Marktech revolutionary ATLAS package combines the hermetic characteristics of a TO metal can packaged optoelectronic device with the great manufacturability associated with surface mount devices (SMDs).

Multiple wavelength LEDs or emitters and photodetectors can be packaged in the larger ATLAS package. ATLAS is an ideal package for applications requiring extreme sensitivity and high reliability because the seam-welded metal-to-ceramic seal in the ATLAS package prevents the ingress of water vapor and oxygen into the cavity holding the LED chips and photodetectors.

Using the ATLAS package technology, Marktech can engineer hermetic packages to hold and protect a wide range of SWIR LEDs, SWIR sensors, and custom LED-sensor combinations to your specific SWIR design application requirements. Marktech also has begun to offer standard or catalog products in the hermetic ATLAS package, such as Marktech’s MTSM1346SMF1-100 High-Speed InGaAs PIN Photodiode, which delivers IR to SWIR (600 nm to 1750 nm) photodetection.

In summary, Marktech’s advanced optoelectronic packaging family includes:

Chip scale packaging – CSP LED or CSP emitters
Hermetic TO can packaging
ATLAS hermetic surface mount device (SMD) packaging
Chip-on-board (COB) packaging using ceramic or Al-cored metal-clad PCB (MCPCB)
Multiple chip packaging – Multiple LEDs, photodetectors, and emitter-photodetector combinations

Conclusion & Next Steps

The high compactness and high power output of Marktech’s new chip-scale short-wave infrared LEDs will enable engineers to shrink and enhance their optoelectronic SWIR design projects. Adoption of CSP SWIR LEDs in new products under development will likely lead to breakthrough designs in many industrial applications.

If you have specific technical or application questions regarding your short wave infrared design project or are just interested in learning more about Marktech’s CSP SWIR LEDs or emitters, then please reach out to us through the following: