During the 2014 trip to China, our supplier YunSun was kind enough to pick us up in Shenzhen and give us a tour of their factory.
Although SparkFun has been using and selling LEDs for over 10 years, I had never seen or really understood how they were made. I let Merry Xiao, our main contact at YunSun, know that we were very interested in learning, so she arranged to give us a tour on a Saturday when the factory was closed. We were extremely grateful!
This is Mr. Si the proprietor of YunSun with the most hilarious sense of humor. He's holding a project that my wife Alicia Gibb is working on. Merry joined us as well and helped translate.
This is a sheet of LED dies. YunSun buys their dies from a high quality Taiwanese company. That's my thumb next to 4,000 dies. The cost for the sheet is roughly 80RMB or $12.50.
Each sheet has the batch characteristics listed in the corner. The dies on this particular sheet have a wavelength of ~519nm or right on the edge between green and cyan blue. Three thin sheets containing 12,000 LEDs soon to be hatched!
The process starts with punched metal lead frames. Each one of these frames has the basic structure for 20 LEDs. Shown above is about 15 frames or 300 LEDs.
The first machine takes the lead frame and applies a small drop of adhesive to each of the cups at the top of the cathode terminal.
As shipped on the paper sheets, the LED dies are too close together to manipulate. There is a mechanical machine (not pictured) that spreads the dies out and sticks them to a film of weak adhesive. This film is suspended above the lead frames, as shown above. Using a microscope, the worker manually aligns the die, and, with a pair of tweezers, pokes the die down into the lead frame. The adhesive in the lead frame wins (is more sticky), and the worker quickly moves to the next die. We were told they can align over 80 per minute or about 40,000 per day.
Above is the LED wire bonding machine. This attaches a hair-thin gold wire from the top of the LED die to the anode lead.
One of the first things that surprised me on this tour was that the entire operation was done in open air. For some reason I assumed manipulating silicon dies required clean room technology. I could do this in my basement! Hmm...
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LED Wire Bonding MachineThis machine took quite a bit of tuning and tweaking to get setup, but once it was up and running, it was impressive to see the unit work automatically without computer aided alignment.
Since there is only one lead being bonded to the silicon die I assume the adhesive on the cathode is conductive. The adhesive sets in about 30 minutes before it goes to the next step.
Here was another surprise. These are 7-segment displays. For some reason, I always thought there was full blown 3mm (or some size) LEDs behind the segments of the display. In retrospect, I was obviously wrong, but it didn't hit home until I saw the 7-segment PCBs with dies directly attached to the board.
A larger picture of the 7-segment bonding machine.
Back to the PTH LED process: Once the wire bond is in place and the adhesive is cured, the lead frame gets placed in the LED mold and gets epoxy resin pushed in around the lead frames.
These molds are what give the LEDs their shape. This was another ah-hah moment. I've seen many different shaped LEDs but always within some sort of dimension. You don't see many 5mm type LED leads with a star shaped head because:
This is one of the mold suppliers' catalog containing a multitude of different shapes and sizes. Again, custom shapes are not impossible, but, if it's not in the catalog, it will be much more difficult to obtain.
Once the epoxy has been injected, we were told the LEDs are baked for 45 minutes. At this point the LEDs can be released from the molds. They are then baked for another 8 to 12 hours to fully cure the epoxy. Once the LEDs are cured they are grouped in large batches shown above.
For support during the manufacturing process, the lead frames have bits of metal connecting the anode and cathodes together. Before testing, the above machine cuts the excess metal away so that the cathode is isolated and all the anodes are bussed together. Why is one pin shorter than the other on an LED? Mostly to ease manufacturing automation and testing. Why did they pick the cathode to be shorter? Probably because it's easier to control the low side (cathode) during testing.
The next step is to test and verify each LED is using the appropriate amount of current. Too little (there is a disconnect) or too much (there is a short) and the LED is removed. Using a series of pogo pins this machine quickly tests each individual LED and displays the output on the computer. This is extremely similar to the pogo pin test jigs we design to test SparkFun products.
Once the LEDs pass QC, they go through another cutting step to separate the anodes from the lead frame.
Lots and lots of 5mm red LEDs built just for SparkFun!
Using this same process, a lot of different shapes, colors, and sizes can be made.
Overall the factory was compact and well laid out. There were four lines available to create whichever shape and type were needed that day.
Merry, Alicia, myself, and Mr. Si. We are very very grateful to YunSun for giving us a tour on their day off! If you ever need LEDs or LED light bulbs consider contacting Merry (merry at 100led.com). YunSun is a wonderful company to work with.
Light Light-emitting diodes or LEDs refer to a source of light. When electrons pass through the material of a semiconductor, it turns on the light. LEDs come in different manufacturing types like flashlights, bulb lights, lamps, etc. Each product serves a different purpose.
Generally, LEDs are divided into two main types: Low-powered LEDs and High-powered LEDs.
LEDs contain a tiny chip and layers of semiconductor material. The package of LEDs also contains more than one chip, which is mounted over the thermal conductive material. This material is also called a heat sink and is covered with a lens. It forms a 7-9 mm thick device that can be utilized in several products and applications.
After this, LEDs are placed over a circuit board, enabling it to control light like diming, pre-set timing, and sensing. The circuit board also contains a heat sink which further enhances the thermal resistivity of the LED. After this, the LED and circuit are enclosed in a structure like a light bulb or light fixture to give it a more appropriate look.
In this innovative era, LED design requires more creativity. Before manufacturing LED light, it goes through a designing phase which includes details like color temperature, efficiency, light application, and brightness of the LED. Several factors like the size of the diode, material of the semiconductor, impurities types, and diode thickness in each layer significantly affect the attributes of the LED light.
Hence, if you want a customized design of the LED light, then reach out to our team of Vorlane to ensure your requests. We firmly believe that each request of clients has a doable solution.
The process of manufacturing LED lights involves the following four steps.
Semiconductor materials like arsenic, gallium, or Phosphor go under high temperature and pressure chambers. It liquifies the material, which is then deposited over a rod. It forms an ingot on the road. Wafers are then cut from the ingot, uniformed, and dipped in a special solution to eliminate contamination.
Manufacturers then add layers of crystal to the wafer with the help of the LPE process. The deposition of dopants and molten GaAsp mixture over the wafer grows crystal layers. They also add dopants in a furnace that contains dopants in gas form at high temperatures.
After this process, manufacturers deposit a photoresist substance over the wafer as it moves in a circle to develop a preset design on its surface. The substance hardens at almost 215°F temperature and exposes the wafer to the Ultraviolet light which creates a duplicate design on the photoresist.
It then fills the exposed areas with contact metal over the vacuum-sealed furnace at high temperatures. They put the LED in the chamber with a nitrogen atmosphere and inert hydrogen environment and then heat it to create a bond of metal with the surface of the wafer. In the end, manufacturers cut the wafers to make around 6000 dies.
They mounted the dies with a package. The backside of a die gets a coating of metal to create an electrical contact. The manufacturing is vacuum sealed in epoxy mold to create a desired shape.
LEDs offer a wide range of benefits. Some of those benefits include:
LEDs are used in a variety of devices and applications. Some of the applications include:
The art of creating LEDs starts with semiconductor fabrication, a process demanding unmatched precision. Achieving consistency across each wafer presents a formidable challenge, essential for the reliability and performance we’ve come to expect from LEDs.
Beyond the technical intricacies lies an economic battlefield. The materials essential for LED production, like gallium, don’t come cheap. Fluctuating prices add another layer of complexity, impacting the affordability of the final product.
In the fast-paced world of LED manufacturing, staying ahead means relentless innovation. But with advancement comes the pressure of competition and the hefty price tag of research and development, pushing manufacturers to their limits.
While LEDs are celebrated for their energy efficiency, the manufacturing process isn’t without environmental concerns. The quest for safer, more sustainable materials is ongoing, reflecting the industry’s commitment to reducing its ecological footprint.
As global demand for LEDs grows, scaling production while maintaining quality and sustainability standards is a juggling act. It’s a testament to the industry’s resilience and ingenuity, ensuring that the future remains bright, one LED at a time.
In the world of LED manufacturing, challenges abound—from the precision of semiconductor fabrication to the pressures of innovation and sustainability. Yet, it’s these very challenges that drive the industry forward, illuminating the path to a brighter, more efficient future.
The manufacturing industry is rapidly growing with advanced technology and innovative ideas. It was impossible to manufacture wafers with purity and uniformity a few years ago, however it is doable now. The integration of wafers in the light enhances the efficiency, brightness, and durability of the LEDs.
LEDs become a high demand and necessity for applications like undersea electronics and outer space gadgets. The process of incorporating more LEDs on a small chip makes them more efficient and demandable.
Vorlane is a leading brand of manufacturing high-quality LEDs and lighting solutions. Since the development of Vorlane, we have gained enormous popularity and won the hearts of various customers. You can give your full trust to our various manufacturing capabilities which include heat tempering to enhance glass specialty, strength, and services. Vorlane is a companion and one-stop solution for all your LED lighting solutions. Visit our website or reach out to us to book a meeting about understanding LED light systems.
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