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How LEDs Are Made

Soulskill posted about 4 months ago | from the when-a-two-flashlights-love-each-other-very-much... dept.

Hardware 93

An anonymous reader writes "The SparkFun team took a tour of a factory in China that manufactures LEDs. They took lots of pictures showing the parts that go into the LEDs, the machines used to build them, and the people operating the machines. There's a surprising amount of manual labor involved with making LEDs. Quoting: 'As shipped on the paper sheets, the LED dies are too close together to manipulate. There is a mechanical machine ... that spreads the dies out and sticks them to a film of weak adhesive. This film is suspended above the lead frames ... 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.'"

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Only 40,000 a day? (0, Redundant)

Marlin Schwanke (3574769) | about 4 months ago | (#47131871)

Pretty sure that if I force my slaves...er...employees to work 12 hour shifts then they will do 57,600 a day...they can pee and have a meal after their shift is over in their cells...I mean barracks. CEO Lucky Good LED Industries CHINA

Re:Only 40,000 a day? (0)

Anonymous Coward | about 4 months ago | (#47131975)

From TFS:

There is a mechanical machine

Was there some other kind?

Re:Only 40,000 a day? (1, Redundant)

Jmc23 (2353706) | about 4 months ago | (#47132065)

pneumatic, hydraulic, etc...

Re:Only 40,000 a day? (2)

K. S. Kyosuke (729550) | about 4 months ago | (#47132229)

They are also using some biological machines, apparently.

Re:Only 40,000 a day? (2)

50000BTU_barbecue (588132) | about 4 months ago | (#47135701)

State.

Re:Only 40,000 a day? (1)

roc97007 (608802) | about 4 months ago | (#47132267)

They probably are doing 57K a day, but for political reasons only advertise 40K a day.

Re:Only 40,000 a day? (3, Funny)

PPH (736903) | about 4 months ago | (#47132287)

Understandable. They probably don't let their employees get on Sashdot. Or it would be 1200 per day.

Re:Only 40,000 a day? (1)

davester666 (731373) | about 4 months ago | (#47137391)

hello...there is a reason buckets were invented...so slaves can pee whenever they need to at their station...

Down with Beta! Down with Dice! (-1, Troll)

Anonymous Coward | about 4 months ago | (#47131923)

Speak up people or the tyranny will never end.
 
Boycott Dice!

Re:Down with Beta! Down with Dice! (0)

Anonymous Coward | about 4 months ago | (#47132033)

Go to reddit!

We don't care!

Re:Down with Beta! Down with Dice! (0)

Anonymous Coward | about 4 months ago | (#47133093)

That's funny considering probably a third or more of the stories here are lifted from reddit.

Re:Down with Beta! Down with Dice! (1)

Anonymous Coward | about 4 months ago | (#47132245)

beta sucks. When will it be canceled?

'cause this is news for 10-year-old nerds. (-1, Troll)

xxxJonBoyxxx (565205) | about 4 months ago | (#47131933)

>> How LEDs Are Made

Because SlashDot is news for 10-year-old nerds. (New Editors: WTF do you think SlashDot is - the text version of the Discovery channel?)

Cheap labor versus automation (4, Insightful)

Ichijo (607641) | about 4 months ago | (#47132021)

There's a surprising amount of manual labor involved with making LEDs.

You have to expect that in a country where manual labor is cheap. In other countries, it makes more economic sense to automate or otherwise fix inefficiencies in the manufacturing process [theatlantic.com] .

Re:Cheap labor versus automation (2)

DocSavage64109 (799754) | about 4 months ago | (#47132045)

I'm suddenly thinking that my job isn't so bad... I would go insane after the first three minutes.

Re:Cheap labor versus automation (1)

Jason Goatcher (3498937) | about 4 months ago | (#47132113)

I have a similar situation in my Runescape game. I've come to realize that tedium mostly exists when you have to actually think in order to do a boring activity. Once the activity is totally automatic you can zone out. That's why all the high-ranking RS players watch tv and listen to music while they play.

Re:Cheap labor versus automation (1)

roc97007 (608802) | about 4 months ago | (#47132313)

I'm suddenly thinking that my job isn't so bad... I would go insane after the first three minutes.

Some of them probably do too. Eventually.

Re:Cheap labor versus automation (0)

Anonymous Coward | about 4 months ago | (#47133039)

Perhaps Russia can sell them some Trampolenes to get to the moon, start a new space race.

Re:Cheap labor versus automation (1)

citizenr (871508) | about 4 months ago | (#47133927)

I'm suddenly thinking that my job isn't so bad... I would go insane after the first three minutes.

hence safety nets around buildings

https://www.google.pl/search?q... [google.pl]

Re:Cheap labor versus automation (0)

Anonymous Coward | about 4 months ago | (#47135501)

You know foxconns employees suicide rate is lower than China as a whole right?

Re:Cheap labor versus automation (0)

roc97007 (608802) | about 4 months ago | (#47132305)

> You have to expect that in a country where manual labor is cheap.

I'd say, you have to expect that if cheap manual labor exists in any part of the world. The areas where manual labor is cheap will naturally attract these kinds of jobs. Why bother building a machine to do it when people in abject poverty exist who will do it for a crust of bread?

Re:Cheap labor versus automation (1)

PsychoSlashDot (207849) | about 4 months ago | (#47132587)

You have to expect that in a country where manual labor is cheap. In other countries, it makes more economic sense to automate or otherwise fix inefficiencies in the manufacturing process [theatlantic.com] .

I'm not saying you're wrong, but I'd like to highlight that there is a second side to your coin. In other countries, it makes more economic sense to automate the manufacturing process so a larger percentage of the profit is converted to profit for those employees that remain, while those who would have done the inefficient manual assembly become unemployment statistics.

Somewhere in between your statement and mine likely lies an ideal.

Re:Cheap labor versus automation (1)

Rockoon (1252108) | about 4 months ago | (#47133593)

In the world I live in, the wealth of a country is properly defined as the amount of goods and services that its people enjoy.

Greater efficiencies is the road we should always be on.

Re:Cheap labor versus automation (3, Interesting)

TubeSteak (669689) | about 4 months ago | (#47133219)

--American unions are changing their priorities. Appliance Park's union was so fractious in the '70s and '80s that the place was known as "Strike City." That same union agreed to a two-tier wage scale in 2005--and today, 70 percent of the jobs there are on the lower tier, which starts at just over $13.50 an hour, almost $8 less than what the starting wage used to be.

--U.S. labor productivity has continued its long march upward, meaning that labor costs have become a smaller and smaller proportion of the total cost of finished goods. You simply can't save much money chasing wages anymore.

Your article glides over this very quickly, but it's worth discussing further.
Management has essentially halted the growth of wages for decades and this has allowed all the productivity gains to accrue to business profits.
The knock on effects have ripped through the economy, from skewed stock valuations to screwed workers' debt loads.

http://tcf.org/assets/images/blog_images/20120814-graph-of-the-day-does-productivity-growth-still-benefit-the-american-worker.png [tcf.org]
You can find other graphs that break down the wage growth by percentile (20th, 50th, 95th) and it's pretty much exactly what you'd expect.

Re:Cheap labor versus automation (1)

roman_mir (125474) | about 4 months ago | (#47165561)

--U.S. labor productivity has continued its long march upward, meaning that labor costs have become a smaller and smaller proportion of the total cost of finished goods. You simply can't save much money chasing wages anymore.

Management has essentially halted the growth of wages for decades and this has allowed all the productivity gains to accrue to business profits.

Actually labour costs have become smaller and smaller proportion of total cost of business because the government made USA worker too expensive and made running a business too expensive, so wherever possible costs will be shifted from buying labour (and labour is just another price, labour is just a good/service that is provided at a price, nothing else, when prices go up people end up changing the recipe, and if it means automating away or replacing local jobs with offshore jobs that is what they will do).

USA labour is not more productive, USA MANAGEMENT is more productive by using less and less USA labour. USA labour is too expensive to use thanks USA government. USA workers are LESS productive than before because they are no longer employed.

Re:Cheap labor versus automation (1)

russotto (537200) | about 4 months ago | (#47135509)

Yes, the cheap labor in China (and other countries, but largely China) has probably set back industrial automation 20 years.

An anonymous reader... (-1)

Anonymous Coward | about 4 months ago | (#47132039)

As in an anonymous Sparkfun PR spammer.

closed on saturday (3, Funny)

rogoshen1 (2922505) | about 4 months ago | (#47132041)

The most striking thing to me about that .. article is that the factory was actually closed on a Saturday.

Re:closed on saturday (0)

Anonymous Coward | about 4 months ago | (#47132095)

Source?

Re:closed on saturday (2)

rogoshen1 (2922505) | about 4 months ago | (#47132161)

the god damn article.

Re:closed on saturday (1)

ColdWetDog (752185) | about 4 months ago | (#47133699)

Don't be rude. It's The Fucking Article.

Say what? (0)

Anonymous Coward | about 4 months ago | (#47132191)

They aren't all 3D printed at home?

Luddites!

Somewhat off-topic: why not uncut LED panels? (3, Interesting)

raymorris (2726007) | about 4 months ago | (#47132223)

I suspect this story may draw comments from people who know something about LED manufacturing. If so, I hope someone can answer this question. I noticed that panels of LEDs, such as used for traffic lights or stage lights, are composed of 200 individual LEDs. So the process is:

Cut one LED panel apart, into hundreds of LED cores.
Glue hundreds of leads to the hundreds of fresh cut cores.
Align hundreds of cores into hundreds of little molds.
Inject resin into hundreds of little modes.
Assemble all of the hundreds of resin-covered LEDs back into a panel again.

Why not this?:
Attach ONE set of leads to the LED silicon panel.
Dip the whole dang panel in resin.

Re:Somewhat off-topic: why not uncut LED panels? (2)

Obfuscant (592200) | about 4 months ago | (#47132335)

I'm guessing for the same reason that the hundred of op amps on a wafer aren't all wired up on the wafer: the manufacturing process isn't perfect and you'd have a lot of nonworking or low output LEDs in the middle of your traffic lights, with modern pick and place machines it is automated to put them back into one device, and if you ever need to fix a failed LED it is cheaper to replace one than a whole wafer of them.

Probably also for heat dissipation.

And that traffic lights are a niche market so you'd be limiting yourself to that market by making LEDs that way. And stage lighting needs at least three colors of LED in one package.

Re:Somewhat off-topic: why not uncut LED panels? (0)

Anonymous Coward | about 4 months ago | (#47132355)

Current flow.
The LED lights up where current crosses from the n-type layer to the p-type layer. The resistance of the material is significant (it being a semi-conductor), so there tends to be a single path where the resistance is least and all of the current will flow. They already put a transparent contact that completely covers the p-type side to get the current to spread out (the n-type side has lower resistance so it's ok to hook up your contact at just the edge), but I imagine this starts working less well as the die gets bigger and bigger. Eventually your giant LED is not going to be even brightness (or parts of it may not light up at all a the voltage drop becomes too high with increased resistance).

You probably could have dozens of fine wires hitting spots spread out over a large LED die, but I'm not sure how much the shadows of those wires would spoil the light output pattern.

Re:Somewhat off-topic: why not uncut LED panels? (3, Informative)

Anonymous Coward | about 4 months ago | (#47132415)

Attach ONE set of leads to the LED silicon panel.

LEDs emit light from the diode junction, not the surface. If you wired up the entire wafer, light would just come out only from the edge of the wafer and the rest would be trapped inside and turn to heat.

Re:Somewhat off-topic: why not uncut LED panels? (2)

Dan East (318230) | about 4 months ago | (#47132421)

All the value and cost of the LEDs is in the silicon dies they get from Taiwan. That's why they cram 4,000 dies onto a silicon sheet the size of a postage stamp. The labor required to manually pull them off is cheaper than the material and manufacturing process of the die.
The surface area of a stoplight led panel would be at least 40 dies worth. That's 160,000 LEDs worth of silicon and production time in the fab plant. Just to get 200 LEDs worth of illumination using your technique. Plus, setting up the fab to produce the silicon would be a large initial investment. There's no way it makes sense to make that manufacturing proprietary to something as specific as the stoplight application. It makes about as much sense as building a plant to make custom nails to build one house.

Re:Somewhat off-topic: why not uncut LED panels? (0)

Anonymous Coward | about 4 months ago | (#47132433)

This is merely supposition, but splitting the LED into smaller LEDs allows small parts of the entire panel to go out without losing the whole traffic light?

Re:Somewhat off-topic: why not uncut LED panels? (1)

zmender (573290) | about 4 months ago | (#47132615)

First, LEDs are not grown on silicon. Most of the manufacturers in the world is based on sapphire wafers, and some U.S. based manufactures use SiC wafers.
Second, consider the physics of LED: you have a lot more control over current spread and light extraction if each die is individually treated.
Third, think of extra manufacturing technical difficulties as you saw through layers of different materials, each with different thermo and tensile properties.

Re:Somewhat off-topic: why not uncut LED panels? (1)

Anonymous Coward | about 4 months ago | (#47132797)

What you just described is called a Chip on Board (COB) LED. They are just coming out now with single units ranging from 10 - 150+ watts. They are designed for use in streetlights and high bay lighting.

I just got done using one for my design project to make a tracking LED spotlight. You can watch a video of the light below.

http://www.calvin.edu/academic/engineering/2013-14-team9/

Re:Somewhat off-topic: why not uncut LED panels? (3, Informative)

b1t r0t (216468) | about 4 months ago | (#47133003)

I work in a part of the commercial lighting industry, and the current technology is indeed surface-mount LEDs, sort of like what you see on strip lighting, only on a metal PCB (for heat dissipation, naturally). Just run everything through a pick-and-place machine and roll it through the reflow oven. The lenses are clear plastic light pipes mounted through holes in a metal fascia. (And I was lucky enough to be able to pick up a bunch of LEDs that fell out of the PnP when we were making some a couple of years ago. Heavy parts do that.)

I doubt they're ever going to move to mounting bare dies (like in seven-segment displays) because they'd have to have their own wire bonder and epoxy, and I'm going to guess that white LEDs need the phosphor applied between mounting the die and molding the lens, so that's one more step. Some customers want Made in USA stuff, and that would be a true pain in the ass to do die-mount in the US vs. a tube of surface-mount LEDs and a normal pick-and-place machine.

I'm pretty sure just from the way they look that traffic lights are using regular 5mm or 8mm LEDs. Even if they used surface-mount LEDs, they'd still need a lens somewhere, and die-mounts would of course be even more trouble. You would have to buy the whole thing pre-made from China with die-mount. The only reason seven-segment (and presumably matrix) LEDs use die mounts is that they can be sold as a single pre-packaged part, and they're too small to even use 3mm molded LEDs.

Re:Somewhat off-topic: why not uncut LED panels? (0)

Anonymous Coward | about 4 months ago | (#47135535)

No die-mount in the US you say? I happen to know that is false. http://norluxcorp.com/ps-assem... [norluxcorp.com]

Re:Somewhat off-topic: why not uncut LED panels? (2)

imsabbel (611519) | about 4 months ago | (#47133097)

They would be too bright, and too expensive. Those 5mm LEDs (outdated crap) have LED dies of a less than 1/20th of a mm^2 inside.

High-end power LEDs that put out the equivalent of a 100W incan bulb are 2-4mm^2.

A disk the size of a traffic light would be able to draw 10000s of Amps, and be bright enough to illuminate a stadium (if you could drain the waste-heat away). Driving it with lower currents would be a collosal waste of dies.

So the wavers are cut into conveniently sized pices that have reasonable power draw and thermal conductivity and then later are put together according to the requirements.

thanks (1)

raymorris (2726007) | about 4 months ago | (#47133605)

I suppose that makes sense - if a CPU can have millions of transistors in less than one square inch, the wafer density is way to high to have only a few hundred diodes on a chip large enough to handle the heat. Unless of course much, much larger process sizes were much, much less expensive.

Re:Somewhat off-topic: why not uncut LED panels? (1)

thegarbz (1787294) | about 4 months ago | (#47138881)

I would say having to redesign a manufacturing system would essentially drive up cost, and then they'd have to compete with the existing products.

Circuit boards are cheap, LEDs are cheap, pick and place and wave soldering is cheap. In the end you get a fully completed module. You're proposing a change in the LEDs that ultimately will still require circuit boards, pick and place, and wave soldering after to get the associated electronics working.

Effectively you're looking at a fixed cost for the board and driver and then the choice of 40x $0.1 components, or 1x $10 component.

Mind you there are applications for high density arrays, but currently their main application is power output, not cost reduction. For instance this array from Cree is looking at about 15000lm of light compared to around 100lm for a single high brightness LED or the 1700lm needed for a single traffic light.

If you lit up those 40000 modules at once you'll combust :-)

great photowork there (0)

Anonymous Coward | about 4 months ago | (#47132227)

They took lots of pictures showing...the machines used to build them

Yes, they showed them alright, from nearly 10 ft away, without so much as a pointy arrow towards the part they are talking about, not that you'd be able to tell anything from that distance anyway. Seariously, they could be taking pictures of any random industrial machines and you wouldn't know the difference. I was hoping to actually SEE how they're made...considering that's what the title says...

Re:great photowork there (3, Informative)

50000BTU_barbecue (588132) | about 4 months ago | (#47132453)

My interpretation is as follows. The equipment shown is stuff that could have existed in the 1960s. In the West, that's pretty much how machines looked like in the 60s. The #1 company that made and still makes these machines is Kulicke & Soffa.

http://www.kns.com/en-us/Pages... [kns.com]

China basically scoured North America for all the old machines they could find. Ribbon machines that make incandescent lightbulbs. Pick and place machines. Board plating shops. Wire and ball bonders.

All this stuff that used to the define the West's technological prowess. K&S is now based in Singapore.

https://www.youtube.com/watch?... [youtube.com]

Oh, and if you want to see something fast and automatic, look up chip shooter on youtube...

Re:great photowork there (1)

50000BTU_barbecue (588132) | about 4 months ago | (#47132519)

https://www.youtube.com/watch?... [youtube.com]

there you go, some closeups of some other junk being bonded.

Re:great photowork there (1)

WillRobinson (159226) | about 4 months ago | (#47135087)

Hate to tell you, K&S is not the leader in die bonding or wire bonding, but thats just from my observation in factories full of die bonders and wire bonders.

I design build and install backend semiconductor equipment, since the late 70's.

Back in the 1980's huge factories in Asia were installing the latest automated equipment. It was not unusual for us to install die bonders that were capable of 5k parts per hour per machine. In groups of 40 machines per device.
These were dedicated to a particular type of lead frame. But could mount multiple types of die. We had lines of 2N2222's at customers putting out over 20 million parts per week, all in a area the size of that room shown, including wire bonding. They had streamlined the whole process including injection molding, testing, and marking in a area only 5 times that room size. Before the automation there was 1000 girls per shift doing the same thing.

I was amazed that the Asian factories had such good automation compared to what I had see in factories here in the USA. But it was truly due to total volume. Here I NEVER saw a factory if the scale I would see there. Now I used to put this over to just labor, overhead cost etc in my mind back then. Later I would think it was due to regulation. Instead I now put it to foresight. They they knew if they could do it even 1/10 cent cheeper they would get the work. And if they got the work, it would never come back here to the USA. And they were right.

Led work is somewhat slower, especially those T1 frames they are using. They have to be handled vertically, and the spacing in between is large. So indexing time and centering of the cup takes a bit more work. Back when we did make machines for that product, the typical machine ran about 2K parts per hour. I am sure now, a bit faster indexing is possible. Thats why so many leds now are done on flat stock and molded and surface mounted, density and speed of manufacturing is much higher.

What they are showing is a cheep startup. Sales of led's by the container load are cheep, as it is a very stable process and anybody can do it. Where the problem comes in is manufacturing variables mostly in the wafer to have even appearing leds. Since the majority of leds are for human viewing, doing things like stop lights or where there are more than one led per product, we want them to appear the same, and look the same over time. So if you get led's from different lots they can appear to be different to the human eye. Especially if they are high output, as heat dissipation over time really degrades the device. That is also why they dont mount die directly to a PCB for stop lights. You can see if one die is different from the other, and while it is possible to adjust each die with a resistor, this adds another step, laser trimming of resistors using visual feedback. The cost of changing out a led made on a metal frame, and the cost of laser trimming is vast, when speed of manufacturing is involved. Much cheaper to just remove the leds and put another in, same for repair. If you pot a lens over a single pcb with multiple dies, it is no longer repairable.

Greener than robots? (1)

iamacat (583406) | about 4 months ago | (#47132321)

Machines may be more efficient, but they would need to be manufactured and run on coal electricity. Perhaps we should encourage handmade electronics for the time being.

Re: Greener than robots? (1)

Bartles (1198017) | about 4 months ago | (#47132849)

Yes. And we should wear homespun clothing, hew our own logs for our houses, and drink raw milk from Bessie out back. Its not green. It's stupid.

Re: Greener than robots? (1)

iamacat (583406) | about 4 months ago | (#47141137)

Actually all of these things WOULD probably be green, if a local forest is not overexploited. You may not have time to do them, but people working in these factories have no better employment prospects. Else they would leave already.

SparkFun. Really? (0)

tquasar (1405457) | about 4 months ago | (#47132385)

So, SparkFun can be surprised that a labor intensive process is done in a place that pays employees not very much money? You do the lookup to see what China factory workers earn in a day or week and see how they live. It's nigh impossible to purchase a small appliance or even our favorite tech items that aren't part of this dark and dirty manufacturing scene.

Re:SparkFun. Really? (0)

Anonymous Coward | about 4 months ago | (#47133317)

its not even that labor intensive for anyone else in the world making serious LED's that are actually useful ... but yea when you go to a factory that is selling 1000 LED's for a nickle on alibaba, thats what you see.

left out the most important steps (5, Interesting)

zmender (573290) | about 4 months ago | (#47132541)

Note: I am speaking as a material engineer who spent about 6 years in R&D for the 65W LED bulbs you can now buy at HomeDepot. The articled failed to mention the most important aspects of the LED manufacturing: wafering and the MOCVD that deposits the light emitting materials (the PN junction) onto the wafer. In short, the steps would include: 1) Crystal growth / wafering / surface prep; (make the wafer) 2) Nitrite epitaxial growth; (grow the light emitting part) 3) Wafer fabrication (cut big wafers down to die-sized chunks) 4) Packaging and testing (encapsulating the die) -- what the article was describing The article only touched upon the 4th step of LED manufacturing, and concidently, the most automated aspect of manufacturing, as well as the part that contains the least amount of patents / trade secrets. The first 3 steps were marginalized as "This is a sheet of LED dies. YunSun buys their dies from a high quality Taiwanese company". To my knowledge, there is no high quality manufacturer in Asia outside of Japan. Samsung makes a great quantity of ok stuff, and China / Taiwan makes a great quantity of shitty stuff that is ruining the entire high profit margin products. Also, all of the major manufacturers of LED dies dare not introduce step (2) and (3) into China / Taiwan due to IP issues. Wafering is important because larger wafer sizes (2in to 4in to 6in) means more dies per area. However, crystal quality becomes harder to control as sizes go up, especially for US-based LED manufacturers that is based on silicon carbide instead of sapphire. The real issue is with the MOCVD, the deposition technique that grows the PN junction which actually emits light. In the world of deposition, MOCVD is archaic voodoo magic and we spent a lot of time praying to deities of deposition that our process would repeat for more than a day. Fab is more systematic than epitaxial growth, and the real science here has to do with light extraction. Again, big money is spent on R&D here, and we dare not bring the manufacturing process to Asia (except for Japan).

Re:left out the most important steps (5, Informative)

zmender (573290) | about 4 months ago | (#47132629)

Messed up my formatting.

Note: I am speaking as a material engineer who spent about 6 years in R&D for the 65W LED bulbs you can now buy at HomeDepot. The articled failed to mention the most important aspects of the LED manufacturing: wafering and the MOCVD that deposits the light emitting materials (the PN junction) onto the wafer. In short, the steps would include:

1) Crystal growth / wafering / surface prep; (make the wafer)
2) Nitrite epitaxial growth; (grow the light emitting part)
3) Wafer fabrication (cut big wafers down to die-sized chunks)
4) Packaging and testing (encapsulating the die) -- what the article was describing

The article only touched upon the 4th step of LED manufacturing, and concidently, the most automated aspect of manufacturing, as well as the part that contains the least amount of patents / trade secrets. The first 3 steps were marginalized as "This is a sheet of LED dies. YunSun buys their dies from a high quality Taiwanese company". To my knowledge, there is no high quality manufacturer in Asia outside of Japan. Samsung makes a great quantity of ok stuff, and China / Taiwan makes a great quantity of shitty stuff that is ruining the entire high profit margin products. Also, all of the major manufacturers of LED dies dare not introduce step (2) and (3) into China / Taiwan due to IP issues.

Wafering is important because larger wafer sizes (2in to 4in to 6in) means more dies per area. However, crystal quality becomes harder to control as sizes go up, especially for US-based LED manufacturers that is based on silicon carbide instead of sapphire. The real issue is with the MOCVD, the deposition technique that grows the PN junction which actually emits light. In the world of deposition, MOCVD is archaic voodoo magic and we spent a lot of time praying to deities of deposition that our process would repeat for more than a day. Fab is more systematic than epitaxial growth, and the real science here has to do with light extraction. Again, big money is spent on R&D here, and we dare not bring the manufacturing process to Asia (except for Japan).

Re:left out the most important steps (1)

nmb3000 (741169) | about 4 months ago | (#47132925)

Interesting, thanks for sharing.

If you happen to know, I noticed in the picture of the sheet of dies [sparkfun.com] that there are a fair number of gaps. Are these failures in the die manufacturing process, or something else?

Re:left out the most important steps (0)

Anonymous Coward | about 4 months ago | (#47133803)

Go Cree! Yay to Epi R&D...

Re:left out the most important steps (1)

Areyoukiddingme (1289470) | about 4 months ago | (#47133907)

Note: I am speaking as a material engineer who spent about 6 years in R&D for the 65W LED bulbs you can now buy at HomeDepot.

Waitaminute waitaminute waitaminute. You can't do that. This is Slashdot. You're violating time-honored tradition.

First you have to tell us what you know without telling us how you know, so some dumbass can demonstrate the Dunning-Kruger effect. Then you tell us how you know what you know. It's only fair. Gotta keep the post count per article up ya know, or Dice will cry.

Re:left out the most important steps (1)

ArcadeMan (2766669) | about 4 months ago | (#47133989)

What's the best brand/model of LED bulbs to replace fluorescent ones? (classical 40 watts replacement)

Re:left out the most important steps (0)

Anonymous Coward | about 4 months ago | (#47134013)

Epistar in Taiwan makes arguably the highest performance AlInGaP Red LEDs. Their InGaN ones are too shabby too. The U.S./Japan/Germany no longer have a monopoly on the MOCVD growth of InGaN LEDs. Chinese companies are catching up and 1 or 2 have surpassed most of the incumbent LED leaders. A few years ago during the MOCVD boom in China that was not the case. But they have poached engineers from Japan and Taiwan and made up the gap recently.

Re:left out the most important steps (0)

Anonymous Coward | about 4 months ago | (#47135081)

I'm no Material Engineer but your posting is a bit confusing to the tune that either you're bullshiting or you got your priorities mixed up.

If in fact MOCVD is "archaic(sic) voodoo magic" and you spent a lot of time "praying", you are conceding that we don't do it better than anybody else (unless you're asserting that your "Materials Engineer" education and experience is a journey in voodoo and prayer).

And R&D at the manufacturing level is minimal. Given that the factories typically don't manufacture the process equipment themselves.

Lastly I guess you're a China/Taiwan reunification proponent, since when did the Americans withhold IP when they sold Taiwan F-16, Patriot missiles, Harpoon missiles...

Re:left out the most important steps (2)

b1t r0t (216468) | about 4 months ago | (#47133073)

The articled failed to mention the most important aspects of the LED manufacturing: wafering and the MOCVD that deposits the light emitting materials

It didn't "fail to mention" that, it started with the pre-cut dies. This place turns cut dies into finished LEDs, and they documented what they saw. This was in China, and the dies are apparently made in Taiwan (so maybe they are crap), and they weren't anywhere near there.

And yes, fabs are serious alchemy. Like the time when Fairchild was a new company, and they found out that their transistor yields were being affected by workers not washing their hands after taking a leak. The chemicals in urine were fucking up the process.

Re:left out the most important steps (1)

afidel (530433) | about 4 months ago | (#47133575)

Why is the wafer size SO much smaller than in Silicon/SOI manufacturing? 200mm wafers for chips was early 90's tech and the standard has been 300mm for over a decade with 450mm slated to be coming online about now if it hadn't been for the great recession and the shift towards mobile (ie Intel Fab 42 which is now in mothballs).

Re:left out the most important steps (1)

drinkypoo (153816) | about 4 months ago | (#47133631)

Why is the wafer size SO much smaller than in Silicon/SOI manufacturing?

Because those gigantic wafers are very very expensive.

Re:left out the most important steps (1)

afidel (530433) | about 4 months ago | (#47133691)

Not really, according to this [icknowledge.com] chart the raw wafers only cost $125.

Re:left out the most important steps (1)

drinkypoo (153816) | about 4 months ago | (#47133799)

Not really, according to this chart the raw wafers only cost $125.

The wafers go up in price with their size, and the price goes up more than linearly. If it made economic sense to use larger wafers, you can be sure that they would be doing so unless there was a production issue.

Re:left out the most important steps (0)

Anonymous Coward | about 4 months ago | (#47134399)

The short answer to your original question is that the MOCVD machines used to grow crystal on the wafers don't grow as uniformly on larger wafer sizes and can't handle wafers bigger than 200 mm at all.

A longer answer starts with: Those costs are for silicon wafers.

First, understand that for LEDs crystal is grown on top of the wafer (epitaxy) instead of stuff like ion implantation that is used in semiconductor manufacture.
Growing the nitride materials used for LEDs on top of silicon is difficult--the spacing of the atoms in a silicon crystal is nowhere close to the spacing of the atoms in an aluminum nitride crystal (or gallium nitride). A lot of work has to be done to transition from the silicon to the stuff you actually want to grow and not just end up with a pile of crap. (It is also difficult to manage the stress caused by the difference in lattice size). Then there's the problem that the coefficient of thermal expansion is rather different between silicon and the nitride materials. Since the growth is done between 700 and 1100 degrees C, the wafers tend to crack when you cool back down to room temperature. Finally, the MOCVD tools used to grow LEDs tend to not have great uniformity over the entire surface area of large (i.e. 200 mm, 300 doesn't even fit) wafers.
So bottom line: Growing LEDs on silicon is very difficult, there are only about two companies really doing it, and the machines used for epitaxy don't work well with wafers larger than 200 mm.

EVERYONE else grows on sapphire. (Except Cree who grows on silicon carbide, and that's even more expensive.) Both the crystal lattice and thermal expansion is closer to gallium nitride, so growing on them is easier. Obviously sapphire is more expensive than silicon, but the technology to make sapphire wafers is also less mature and they just can't make really good wafers in the sizes silicon has. (200 mm exists but is almost 2 mm thick last I saw; no one uses bigger than 150 mm.)

Caveat: The above is really about high-brightness blue, green, and white LEDs. High-brightness red-orange-yellow LEDs are typically grown on gallium arsenide wafers (150 mm or 200 mm). Low brightness (low efficiency) stuff I think you can make with silicon, I don't know too much about that.

Re:left out the most important steps (1)

the_other_chewey (1119125) | about 4 months ago | (#47134959)

Two factors:

- size doesn't matter (that much): For CPUs, you are creating large (relatively speaking) rectangular
objects on a circle. Thus, the closer your circle outline approaches a straight line (i.e., the larger the circle is),
the less waste silicon you have to cut away. For tiny LED dies, you can basically use the full circle even on
smaller wafers.

- For CPUs, the price is in the processing; for LEDs, it's the materials: LED structures are gigantic compared
to those found on a CPU. They are built using a handful of low precision (again, relatively speaking) production
steps. CPU production is as close to magic as we can nowadays get and uses dozens to hundreds of processing
steps (a wafer for a modern CPU spends about a month inside the fab), where a machine for a single step costs
millions. The cost for the raw wafer itself really doesn't matter.


So:

LEDs are cheap and fast to manufacture, and basically fit on arbitrary wafer shapes:
Raw material prices matter, wafer waste is minimal and doesn't. --> cheap, small wafers.

CPUs are damn hard and slow to manufacture, really only fit on rectangles:
Who cares about wafer prices, but we want optimal yield per processed wafer, so as to have
as little waste as possible --> wafers as large as possible, damn the cost of the wafer.


And lastly: There is no structure size progress in LEDs as there is with CPUs: Once you have a
factory for LEDs, you can use it for a while without upgrading to the newest and smallest process
all the time. So why buy new equipment if the old is perfectly competitive?

25 year old technology (1)

imsabbel (611519) | about 4 months ago | (#47132555)

Not just the production way is low-tech, this type of LED is depricated for everything but the cheapest crap available.

Modern LEDs are basically all SMD, the high power ones typically mounted on a solid metal core PCB. And those are acutally manufactured in a more modern type of way.

Re:25 year old technology (1)

50000BTU_barbecue (588132) | about 4 months ago | (#47132597)

Hey hey easy there, my Sky King coaxial remote control helicopter is filled with these LEDs. It looked great for the 15 seconds it flew before it crashed.

Re:25 year old technology (1)

goodmanj (234846) | about 4 months ago | (#47134373)

Sparkfun is a hobby electronics company. Surface-mount LEDs are a pain to solder by hand, and impossible to prototype.

Just Imagine... (1)

Sentrion (964745) | about 4 months ago | (#47132567)

...squinting at tweezers day-in and day-out for most of your life and the toll that would take on your eyes. It must be even harder for tall people with long arms.

interesting for us not involved (1)

k6mfw (1182893) | about 4 months ago | (#47132651)

I never did look into how LEDs are made (hey, I just buy and put them to use) and that it is a "cottage industry." And LEDs are made in open air facilities instead of clean rooms. I can start my own LED factory but unlike the author I don't have a basement.

How is this a beat? (-1)

Moof123 (1292134) | about 4 months ago | (#47132765)

Battery life? Nope.
Weight/convenience? Nope.

If your only goal is to be the brightest guy out there, buy a surplus aircraft landing light.

The real goal is to be visible but not distracting to cars and fellow riders. The lightest, cheap, long battery life solution to that need is the win. Th boring blinkie red light is a pretty good solution today.

now if your goal is to get ready for entertaining the ectasy taking hippies at burning man, then this is might be an OK solution, but as a bike light it stinks.

Re: How is this a beat? (-1)

Anonymous Coward | about 4 months ago | (#47132809)

Wrong story, dumbfuck!

liberal propganda (2, Funny)

s122604 (1018036) | about 4 months ago | (#47132887)

More liberal propaganda to justify our loss of lightbulb freedom

Lead is mentioned some 16 times (1)

Trax3001BBS (2368736) | about 4 months ago | (#47133041)

When I was last involved with lead it was treated as a hazardous material, gloves and a gas mask at the minimum were required when working with it, or around it.

Re:Lead is mentioned some 16 times (1)

Trax3001BBS (2368736) | about 4 months ago | (#47133065)

Gas mask- a common term used for any full face breathing protection.

Re:Lead is mentioned some 16 times (1)

imsabbel (611519) | about 4 months ago | (#47133113)

When was the last time you have seen somebody use a soldering iron with has mask and gloves? In contrast to europe, american solder is still lead based.

Re:Lead is mentioned some 16 times (1)

QuasiSteve (2042606) | about 4 months ago | (#47133135)

A lot of 'American Solder' is actually also available as RoHS, simply because it ends up getting used for the manufacture of items that need to be exported outside the U.S.
Similarly, I can walk into a local electronics store in Europe and get plain ol' 63/37 just fine for my own hobby use

Not that the lead in the article has anything to do with the lead we're discussing here.

Re:Lead is mentioned some 16 times (2)

MattskEE (925706) | about 4 months ago | (#47133287)

The lead frames are not typically made with any lead, it is just a case of easily confused homonyms.

In "lead frames", "lead" refers to the metal pins coming out of the packages, which are connected to the LED die. It not typically made with any lead content (Pb, element 82) due to RoHS restrictions. It could be made of tin-plated copper, or various alloys of tin, copper, and silver. Older ones would likely have been Pb-plated copper.

That would be pronounced "LEED"... (1)

Ellis D. Tripp (755736) | about 4 months ago | (#47133297)

They were referring to "lead frames", the wire terminals and internal die supports used in a semiconductor package (before the plastic overmolding is done).

Nothing to do with the toxic heavy metal with the symbol Pb.

Re:Lead is mentioned some 16 times (1)

goodmanj (234846) | about 4 months ago | (#47134377)

"Lead" pronounced "leed", meaning something used to guide (electric current, in this case).

impressive Americans (1)

argStyopa (232550) | about 4 months ago | (#47133231)

Go to a foreign country, get invited to take a rare trip through a valuable suppliers factory.

This supplier carefully dresses up for his guests, and makes sure his factory is spotless for the important, honored visitors.

And you show up in a ratty t shirt and wtf are they,capri shorts?

Nothing like showing respect for your hosts. What did you bring as a gift, a used newspaper you read last week?

Re:impressive Americans (0)

Anonymous Coward | about 4 months ago | (#47133337)

so a "supplier" that makes 30 year old technology by hand in their garage is valuable?

Re:impressive Americans (0)

Anonymous Coward | about 4 months ago | (#47134167)

so a "supplier" that makes 30 year old technology by hand in their garage is valuable?

Yes, a lot more valuable than than you, since you aren't a supplier at all.

Re:impressive Americans (1)

goodmanj (234846) | about 4 months ago | (#47134393)

Seriously. Adapt to the local social norms, moron, you're making me embarrassed to be an American.

(Well, okay, that's far from the most shameful thing we Americans have done overseas, but still.)

How LEDs are made? (0)

Anonymous Coward | about 4 months ago | (#47133295)

The hell with that. I want to see how babies are made.

Oh, wait...

this is another factory (1)

Anonymous Coward | about 4 months ago | (#47133753)

this is another factory with more automation.

https://www.youtube.com/watch?v=dDcMarYHknA

Many hands (1)

Chocolate Teapot (639869) | about 4 months ago | (#47134667)

make light work!

Made by hand (1)

mrflash818 (226638) | about 4 months ago | (#47135791)

I never knew this style of LEDs were mostly made by hand.

I always assumed it was done by an automated assembly line, like how (mostly) CDs and DVDs are created on automated assembly lines.

Now would enjoy it, if someone could tour a LED light bulb factory, and share how those are made.

Re:Made by hand (0)

Anonymous Coward | about 4 months ago | (#47136271)

This factory made that way, perhaps the value their employees enough to no replace them with machines.

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