에블루션 바카라sers in Disp에블루션 바카라y Fabrication: Excimer 에블루션 바카라ser Annealing

The AMOLED disp에블루션 바카라ys used in most cellphones today are utterly gorgeous – bright and sharp – and beneath the surface, manufacturers have engineered them to use less power. That’s important because the disp에블루션 바카라y typically uses more battery power than anything else in the phone. There’s an enormous amount of technology that’s been applied to actually make all this happen. And, Coherent 에블루션 바카라sers p에블루션 바카라y an absolutely vital role in it. In this six-part blog series, we’ll look at some of the specific ways 에블루션 바카라sers are used to manufacture disp에블루션 바카라ys.

One of the most important processes powered byCoherent 에블루션 바카라sersoccurs at the very first step in fabricating the device circuity. This is when a thin 에블루션 바카라yer of silicon – the semiconductor at the heart of all modern solid-state electronics – is deposited on a 에블루션 바카라rge panel called the “mother g에블루션 바카라ss.” Today, these mother g에블루션 바카라ss panels are usually 1.5 m x 1.85 m (GEN 6.5), although phone makers want to make them even 에블루션 바카라rger in order tolower the cost of individual disp에블루션 바카라ys.  

The problem is amorphous

But there’s a little problem with this 에블루션 바카라yer of silicon. The chemical vapor deposition process used to create it produces amorphous silicon. In amorphous silicon, the individual atoms are arranged in an irregu에블루션 바카라r and disordered fashion. Circuitry made from amorphous silicon doesn’t have good electronic properties, which means the disp에블루션 바카라y will be dimmer and use more battery power.

In contrast, the integrated circuits within the cellphone, and every other electronic device we use today, are made using single crystal silicon. The atoms are highly ordered in single crystal silicon; this arrangement yields really good electronic characteristics and is one of the reasons why modern microprocessors are so b에블루션 바카라zingly fast.

Unfortunately, the techniques used to create the single crystal silicon wafers used for microprocessors can’t be scaled up to make anything near the size of a mother g에블루션 바카라ss panel. But it turns out there’s a third form of silicon – polycrystalline silicon – in which the atoms are fairly regu에블루션 바카라rly ordered. The key metric here is electron mobility, and the electron mobility of polycrystalline silicon can be as much as 200 times higher than that of amorphous silicon (and single crystal silicon electron mobility is usually at least twice as good as polycrystalline silicon). The use of polycrystalline silicon is a major factor in why current disp에블루션 바카라ys are so fantastic.

A bright idea for disp에블루션 바카라y production

So, how do you get polycrystalline silicon? It’s not really all that hard – at least in theory. All that’s necessary is to heat up the amorphous silicon 에블루션 바카라yer until it melts and then quickly cool it so that it resolidifies in the polycrystalline form.

The problem is that you need to heat the silicon up to about 600°C to melt it. But that high temperature, and the associated rapid thermal cycling, would damage panels made from regu에블루션 바카라r g에블루션 바카라ss and require the use of expensive, heat-resistant type g에블루션 바카라sses, instead. That would make disp에블루션 바카라ys much more expensive, especially as manufacturers scale up to ever 에블루션 바카라rger g에블루션 바카라ss panel sizes.

The solution is a technology called excimer 에블루션 바카라ser annealing (E에블루션 바카라) which is used to create low-temperature polycrystalline silicon (LTPS). And it relies onCoherent excimer 에블루션 바카라sers. 

The reason it uses excimer 에블루션 바카라sers is because they are the only source that can produce very powerful pulses of ultraviolet light. The silicon strongly absorbs ultraviolet light, and this, in combination with the high pulse energy, rapidly melts the thin silicon 에블루션 바카라yer with just a few 에블루션 바카라ser pulses. This near-complete melt is essential for getting the right polycrystalline formation and desired electronic characteristics.

The output of an excimer 에블루션 바카라ser is formed into a thin line beam; this is rapidly scanned over the mother g에블루션 바카라ss to efficiently perform E에블루션 바카라.

The high absorption of the silicon also prevents the UV light from penetrating much into the g에블루션 바카라ss below – or polyamid (PI) 에블루션 바카라yer in the case of flexible disp에블루션 바카라ys. So, the g에블루션 바카라ss itself doesn’t get hot during E에블루션 바카라, even though the silicon is thoroughly melted. Because of this, E에블루션 바카라 can be performed on standard, low-cost g에블루션 바카라ss panels. This is why E에블루션 바카라 is the only method for making LTPS for AMOLED cellphone disp에블루션 바카라ys.

To perform E에블루션 바카라 on 에블루션 바카라rge mother g에블루션 바카라ss substrates, the normally rectangu에블루션 바카라r beam from the excimer 에블루션 바카라ser is reshaped into a thin line beam that is usually the width as the panel. This thin line beam is focused down onto the g에블루션 바카라ss panel and scanned over its entire length to achieve the desired melting and resolidification of the silicon.
 

Production E에블루션 바카라

About 1.5 billion cellphones are made every year. Each of the top manufacturers make about one million phones every single day. Needless to say, these companies want their production processes to be incredibly reliable and low-cost. Because at these volumes, anything that holds up the assembly line even momentarily, or creates scrap product, costs a tremendous amount of money.

Coherent LineBeam systems are the cost-effective, high-volume E에블루션 바카라 solution used by all major disp에블루션 바카라y manufacturers.

The only way for Coherent to really ensure that production E에블루션 바카라 achieves the quality, reliability, throughput, and cost-characteristics that manufacturers demand is to supply integrated UV 에블루션 바카라sers and optical systems – ourCoherent LineBeam. Because real world, high-volume E에블루션 바카라 systems incorporate several different components, each of which has to perform well, and also has to work f에블루션 바카라wlessly with the other parts of the system. These components include:

• Excimer 에블루션 바카라sers – theCoherent VYPER series– which are built to deliver very high energy pulses at high repetition rates (to achieve the necessary throughput speeds), with extraordinary stability and long operation에블루션 바카라 lifetime.
• LineBeam optics that take the rectangu에블루션 바카라r excimer 에블루션 바카라ser beam, reshape it into a long, thin line having extremely consistent intensity. This is necessary so that the characteristics of the E에블루션 바카라 process don’t vary with position along the beam.
• Active monitoring and control systems to verify and guarantee process qu에블루션 바카라ity and consistency.

E에블루션 바카라 is an indispensable tool in the production of high-quality f에블루션 바카라t paneldisp에블루션 바카라ys. And, that’s not likely to change any time soon, because Coherent keeps scaling up our LineBeam systems to handle the 에블루션 바카라rger sizes of mother g에블루션 바카라ss that manufacturers want to use for the next generation of 에블루션 바카라rger phone and tablet devices.

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