WO2013175052A1

WO2013175052A1 - Coating and material method

Info

Publication number: WO2013175052A1
Application number: PCT/FI2013/000025
Authority: WO
Inventors: Petteri Kinnunen; Jari RUUTU
Original assignee: Arctic Ip Investment Ab
Priority date: 2012-05-22
Filing date: 2013-05-22
Publication date: 2013-11-28
Also published as: FI20120169A; EP2852968A1; EP2852968A4

Abstract

The innovation is targeted at the coating and material production method, which is based on the application of picosecond, femtosecond and attosecond pulses a) in a vacuum, b) in a gas-pressurised mode, c) in liquid state or d) in the clean room standard; the repetition frequency of the pulses is between the span of 100 kHz and 10 Ghz, with fibre reinforcement or semiconductor laser, which operate on the wavelength of the UV-visible-IR light. The laser beams are directed to a separate space a-d) with optic fibres or as a collimated beam and only inside this space is focused to the volatizing / processing material by self-cleansing optics.

Description

Coating and Material Production Method

The method is based on the application of cold ablation primarily to the coating a) in a vacuum, b) in a gas-pressurized mode, c) in an atmosphere of gas, or d) in liquid state. All the essential information concerning the principles of cold ablation is presented in two reference publications, which at the same time serve as support [material] for this document. From now on, they will be referred as Support Publication 1 and Support Publication 2. Significant Solutions

Support Publication 1

Ablation of metals with picosecond laser pulses:

Evidence of long-lived non-equilibrium surface states*

E.G. GAMALY,1 ,3 B . LUTHER-DAVIES ,1 ,3 V.Z. KOLEV,l ,3 N.R.

MADSEN,1 M. DUERING,2 and A.V. RODE 1 ,3

lLaser Physics Centre, Research School of Physical Sciences and

Engineering, the Australian National University, Canberra, Australia

2Fraunhofer Institute for Laser Technique , Aachen , Germany

3Centre for Ultra-high Bandwidth Devices for Optical Systems, Australian

National University, Canberra, Australia

~Received 30 November 2004; Accepted 10 December 2004!

Support Publication 2

Ultrafast Laser Ablation and Film Deposition

EUGENE G. GAMALY, ANDREI V. RODE, and BARRY LUTHER- DAVIES

Research School of Physical Science and Engineering, Australian National University, Canberra, Australia

Actually, in these publications all the necessary information on cold ablation has been presented and proven to be the superior coating method when compared to all the other methods.

If that is the case, why should not the cold ablation method be already in use in industrial production?

As a matter of fact, the physical realization [of the method] depends typically on the technological level, whose basis is not necessarily the cold ablation method itself and vacuum / process cell (chamber) applications which are meant for research use.

Let us have a glance at the reference publications: 1) US PAT

2010/000046A1 , 7.1.2010 and 2) Lamsat University of South Florida -> Pulsed Laser Deposition

In laser ablation, in deed, the laser beam is focused on an extremely small area, typically on a surface area of 10 - 30 μιη in diameter. This is technically challenging, and that the laser beam is typically focused on a target inside the vacuum cell/chamber by a focusing lens outside the cell, which is 200 - 400 mm away, further adds the degree of difficulty.

On page 100 of the RP2, relevant facts are set forth in terms of cold ablation:

1) pulse length

2) energy per pulse

3) wavelength

4) power distribution in the pulse area

Points 1 , 2 and 3 are associated with the operation of laser itself, and what causes the contradiction here is that powerful lasers and lasers with a large repetition frequency operating in the cold ablation area are semiconductor picosecond lasers. These may have the power of even 50 or 100 W, repetition frequency of 20 MHz, pulse energy of 10-20J/cm^A2 and with a typical pulse length of 10 ps.

The problem is that these operate in the IR area - that is to say, with the wavelength of 1064 nm, which is problematic, because the multiple material either reflects that wavelength excellently or that wavelength excellently penetrates the material. In other words, absorption of the wavelength is low, unsatisfactory (poor) in practice.

Femtosecond (fs) lasers operate on UV-wavelength, which is absorbed through all kinds of materials very well. In these indeed, the repetition frequency is typically no more than 1 -5 kHz; therefore, production achieved in ablation is very little.

We have introduced a functioning solution in the new method, to which we will come back later. In TJ 2's image 5.5, it is referred to the quality of the pulse, in which the most relevant information is that the fluence, distribution of power, should be very stable in the spot area. In the document, in picture 5.5., a typical form (shape) of a laser beam pulse is shown. In the picture it is revealed that there is too much power in the center (lOxF), whereas less is needed for a perfect atomization (4xF).

Image 1 ; ionized plasma 5 is generated by micro-optics 1 and 2, directed from two opposite points, into which is advantageously connected two different laser beams representing two different wavelengths. The wavelength of a laser beam 16 and 19 can be, for example in the UV-area or 532 nm, and the other wavelength 18 and 21 can be, for example, 1064 nm. These laser beams, 16/19 and 18/21, which stand for different wavelengths are connected as 17 and 20; thus, two opposite laser beams are formed to be pulsed, either of which has two different wavelengths.

So, all the essential parts and components such as the optic parts 1 and 2 of the micro optics, focusing optics, collimated laser beam connector 17 and 20, and convergence optics of the laser beams 16/18 and 19/21, target 3, rotation motor 22, Z-parallel, for example, piezo-powered transfer equipment, etc., are mechanically attached to each other. These essential components are mechanically connected to a single base (corpus/plinth), and from now on this whole (entity) will be called as the volatization (steaming) module. Presented volatization (steaming) module is placed, for example, on top of the linear motor functioning movement axis 14, so that it can be relocated X-parallel [to] 23 desired drive.

In image 1, the function is displayed, in which laser beam or beams directed somewhere else instead of the actual steaming target surface 3, which is essential for volatization (steaming).

As displayed in TJ1 and in TJ2, in cold ablation too the plasma expands, and in order to compensate that, it is recommended that the pulse energy of the laser beam should be approx. five times (fivefold) as compared to the ablation treshold of each material.

This is one of the problem areas facing the initiation of industrial production, because these picosecond lasers, femtosecond lasers or attosecond lasers do not exist yet. Existing lasers, which may have the repetition frequency of at least 5 MHz and up to always 200 MHz, today can just extend to the level of the ablation treshold. It is already a difficult equation to get the corresponding fivefold pulse energy produced with a minimum diameter of 10 μπι from the target.

As a solution, the new method suggest that one or more laser beams 12 are directed to the plasma 15 as close as possible (0.01 mm - 20 mm), for example, rotating 5 target's 3 surface depending on the material being volatized (steamed) and which other auxiliary processes are in use.

There are two relevant reasons why laser beams 12 are directed to the plasma as well. First of all, if the laser beams were directed toward the target 3 only, it would demand exactly what complicates the application of the USPL method. A very big pulse power compared to the ablation treshold so as to produce fivefold the energy needed. The argument TJ2 puts forward is that otherwise the plasma forms droplets and as an outcome, particles emerge because of the fact that plasma's expansion freezes this fundamentally.

By directing another laser beam 12 toward the arisen plasma, the energy need of the volatizating (steaming) laser pulse is fundamentally reduced. Actually, this extra laser beam has even such an impact that it is possible to plant even more energy to the plasma than the ablating laser beam itself could enable to do so.

Another important task is that it eliminates those errors, which emerge during the actual process of steaming. For example, atom condensation, a clump or even e particle evaporate with this extra beam.

In TJ2, it is put forward how it is essential in coating that the ionized plasma is homogeneous, and then one could talk about very small tolerances.

The new method differs from the known ones in the sense that another laser beam is directed to the plasma, which has come into existence, pulsed in the most economical way and the pulses are in the picosecond class in the most economical way or even shorter.

It should be noted that TJ2 suggests as a final solution the ~ fivefold increase of the pulse energy as compared to the ablation treshold.

Such a regulation entails total absorption in practice; and furthermore, the adjustment of all the parameters becomes extremely difficult because of the precision requirements. The larger the pulse energy is, the larger is the pressure impact in the uppermost atom layers of the target, and the more likely that always physical particles will break away from the surface. In image 1 ; in such a state in cold ablation, where extra energy is needed in the substrate 7, the area in which plasma 15 is placed.

This is how the preparation of single-grain [-crystal] (111) shaped carbon- based materials such as C12 diamond, carbonitrides, pure rubies and sapphires works.

Image 3 displays how it is simple and fast to modify the process altitude 24, in other words, the distance from the root of the plasma, the surface of target 3, to the surface of the task object. The plasma 15, which has been produced with different materials and processing parameters, has different ideal targets (objectives), from which the plasma is supposed to reach the surface of the substrate.

The problem here is the so-called vanes, a.k.a. +1 and -1 external area, where molten materials, particles etc., are formed, because the frequency is not high enough.

It has been suggested that the so-called vanes should be cut off by a

"mechanical" ring, so that a sharp ring-shaped pulse form can emerge.

Now the fact of the matter is that, as shown in TJ2 -documentation, the laser beam is directed to the perpendicular target. This is indeed possible in laboratory environments, but not in industry. Typically, the laser beam is directed to the target at an angle of 45°, in the same way as shown, for example, in the patent application (Imra American Inc.) US 2010/0000466 A 1 or as Lamsat does in its PLD-application. In the first one, it is also shown that the laser beam is directed to the target through the substrate vertically. When directed vertically, the laser beam is the most optimal. Since ablation is performed from the surface vertically, it is often ended up directing the sun beam to the target at an angle of 45° in practice. This deteriorates the quality of the directed laser beam on the surface.

Next, the new method will be introduced with the aid of the images 1 - 17.

Image 4; when the laser beam 26 is directed to the surface of target 29, the power distribution in not naturally the same as when directed vertically. However well the quality of the laser beam might be, as it strikes the target at the angle of 45°, the power distribution of the beam substantially changes in a way that mostly the power of the beam 26 is lower than the arrival direction 27, as compared to the opposite side 28, to which accumulates noticeable power.

A balanced spot area is achieved by the way described in image 5, where two separate laser beams, 30 and 3, are focused from opposite directions to surface of the target, to the same point, 32 and 33. These optic figures form the mirror image of each other. Where the beam 30 produces the minimalistic power 36, the beam 31 produces the maximal power 37. As placed on top of the other, the power distribution in the whole spot area is completely even (stable) 41.

Attention should be paid to the fact that particularly the wavelength would be the same, because it does have an effect on the absorption.

In the new method, it is shown that it is possible to apply two different wavelengths, such as 320 nm (UV-area) and 1064 nm (IR-area), which are connected to the same optics and thus to the same focal point.

Absorption capacity comes from the material and the wavelength. Still, the general direction is that UV (for example 320 nm) is typically absorbed excellently and IR (for example, 1064 nm) reflects, in other words, is absorbed poorly.

Typical semiconductor surfaces and materials, such as Si02, are transparent to the wavelength of 1064 nm. The wavelength of 1064 nm is economical to produce the semiconductor by using diode-pumped laser power.

Thus, laser systems with the output capacity of 1064 nm wavelength and repetition frequency are being used in the way that, for example, 150 pulses are steered to the same application point so as to achieve ablation. This is by no means a cost-efficient way.

Secondly, if once more the wavelength of a 1064 nm-wavelength laser is halved, even twice, so will the power decrease in proportion. Taking what has been introduced in TJ2 into consideration, especially significance of the pulse's quality on the surface of the target in the final result, which is the goal as a matter of fact, it is emphasized that the most optimal final result is reached by connecting UV- and IR-beams to the same focus and spot.

The new method displays the most optimal solution, in which two vaporizing multi- wavelength laser beams are placed against each other (diametrically).

Images 6 and 7 show how the balanced double-wavelength volatization system of the new method functions. Image 6. First, 46 is directed laser beam 42 on the surface of the target, for example, as a 320 nm (UV-area) wavelength; then, absorption is almost 100% in all materials and it is in an extremely limited balanced spot-area with an atomic-layer depth of 1-20, in other words, at an even power distribution in the whole spot area. In that case, depending on the pulse power and the pulse length, we are able to carry the aimed quantity of atomic layers to such an energy level that the subsequent laser pulse 43, which operates, for example, at the wavelength of 1064 nm (IR-area), is absorbed practically 100 % 48. It is essential that this vaporizing/steaming/volatizing laser beam is the type that enables the production of large power outputs and repetition frequencies, which is the key to the industrial application.

As a final result (outcome) comes out an overall ablation process, which, as depicted in image 7, adjusts the parameters of both wavelengths. By parameters we mean primarily a) the pulse power, b) the pulse length, c) the wavelength, d) the repetition frequency, e) the relative timing, and f) the pulse mode (constant/burst/combination of both).

Both of the wavelengths now could have been utilized optimally in terms of the work process. The first wavelength is fully absorbed and elevates the energy level of the atoms near to the ablation point, and the other pulse accomplishes the ablation.

This section (sector), in which the multi-wavelength method is applied to the same spot, has not been implemented all the way to the end. Therefore, we do not precisely know how the pulses with different wavelengths 49, 50, 53, 54 should be placed (positioned) among each other; in other words, we do not know what their mutual pulse power or the length of the pulse in all different materials is.

In TJ2, figure 5.2 demonstrates the effect of the wavelength on the ablation treshold, in which it can be seen that it is 532 nm of part ~l,2J/cm^A2 and 1064 nm of part 2,4 J/cm^A2. So we can assume that it is ~0,8 J/cm^A2 at the wavelength of 300 nm.

In figure 5.3, the effect of the wavelength and pulse length on the

achievement of the ablation treshold is demonstrated. In the picture, the effect of a lower wavelength (for example, 300 nm) can be clearly noted. It is ~ 1/3 when compared to a wavelength of 1064 nm and with the pulse length of 5 ps.

It is also obvious that a wavelength of 10 ps is too long regardless of the wavelength being applied. 1-5 ps as a pulse length is in such an area, which we will pursue.

In most lasers, which are diode-pumped high frequency-semiconductor lasers, it is possible that they can be steered in the so-called burst-mode; which means that various pulses are packed consecutively, for example, at the frequency (fs) of the femtosecond-class.

Figure 8 demonstrates the micro-optics of the volatization module, in which the laser beams can be targeted from four directions with any combination.

The volatilization (steaming) module is a mechanical plinth (base), into which all the necessary equipment are to be placed, such as the 8 micro-optics of the image, the actuation mechanism of the target (for example, on the XYZ- axis or/and in rotation).

The volatilization (vaporizing) module can be static or placed, for example, on the linear axle mechanism, so it can be moved in the direction of several (multiple) degrees of freedom depending on the structure, for example, even as far as the movement distance of 10 meters.

This means that the steaming (volatilization) process can be performed at a (certain) concentrated place, but since it is capable of being moved, at least in one direction, it is plausible to accomplish (produce) a large coating area. This is new; when process area is separated from the production of substance (ionized plasma, an optimal production process for an indefinite area is achieved.

Example 1 ; sheet glass (plate glass), on which the coating is performed, for example, glass heating or thermal insulation / protective coating such as ITO or whatever any functional coating with metals, oxides, nitrides, carbides, etc. The typical size of the sheet glass is 4x6 m, in which from now on the X- direction represents the width of the work piece.

The number of PLD-methods known by application, in other words, the number of possibilities, is exactly 3.

1) The target is scanned from 4-meter sheets.

2) Many scanners are placed side by side (contiguously), for example, a unit of 20 pieces of 20 X 20 cm sheet.

3) Sheet glasses are moved one step at a time and steered over the vaporizing area.

Problems: All the known PLD-methods represent the technology, in which a) the scanner is outside the vacuum / process compartment (chamber), b) the target is inside, c) focusing distance is long, typically hundreds of millimeters, d) the laser beam can only be focused directly on a target which is situated at an angle of 45°, e) the scanner and activators of the target are a fixed

(inseparable) component of the chamber (cell). Equally, exactly the same problems are inevitable in 10" or even in the coating of a smaller semiconductor disc (Imra America US 2010/0000466 Al); in images 6, 7 and 8, it becomes apparent that the laser beam is directed to the vaporizing target through the substrate, and that the substrate can be steered on the XYZ- axis (pg. 3). It is also stated that the substrate can be heated. The method introduced by Imra America is actually the 4th method.

This method presented by Imra America, in which the beam is directed through the substrate, is difficult for many reasons: a) dissipation, when the laser beam is directed through the substrate, b) weakening of the pulse power particularly if the substrate is heated, and c) the work piece should be at least a partially transparent optic piece, which narrows down its application only to particular pieces.

In the new method, the problem is solved in such a way that the volatilization distance can be, for example, only 2 mm even if the laser beam and the target were to be on the same side of the work piece.

Image 9 presents the operational principle of the new method, in which the workpiece, for example, the sheet glass 60 moves in the direction of x at the same time 66, whereas the volatilization (steaming) module 69, in which all the necessary components for volatization such as micro-optics 68, the target 61, etc. are placed, can freely move in the direction of y 63 in such a way that the plasma jet 67 will coat the designated (fixed) area 65.

The volatilization (steaming) module 69 is economically placed on the linear axle 62 of the rotating tray (moving head), where the linear movement may have been actualized by a linear motor in order to get the movement fast, vibrationless and, in addition, the length of the movement in a state without any upper limits. In image 10, the alignment variations of laser beam are presented:

10a. Two laser beams against each other (yis-a-vis)

- both are volatile

a) I oIR

b) 400-800 nm <> 400-800 nm

c) UV <> UV

d) UV <> IR-visible

Directed to the same focal point 10b. Two x two laser beams against each other

- 1 pair volatile: IR- visible-area

- 1 pair volatile: UV-area

10c. Two x two laser beams against each other + two to the plasma

- 1 pair volatile: IR-visible-area

- 1 pair volatile: UV-area

- 1 pair plasma lOd. Two multilength laser beams are against each other

- 1 pair volatile: IR-visible + UV lOe. Two + two multilength laser beams are against each other

- 2 pairs volatile: IR-visible + UV lOf. The same as the previous, but

a) two laser beams to the plasma

b) two + two laser beams to the plasma

c) the same as a) and b), in which still one more laser beam is directed to the substrate. lOg. The optics directing the laser beams is a) static

b) placed on a moving plinth (base), which has 1, 2, 3 or more moving axles / degrees of freedom (X, Y, Z, ...). lOh. Above mentioned, into which could as well be placed

- a microwave transmitter system

- a bias-system

- a magnetic field system, electric/static

- a gas feeding system, shielding gas or reactive gas

- an ion cannon lOi. The previous, in addition to the alignment optics of the laser beam, always includes

- The rotation mechanism of the target, if there is a rotating target in question

- The steering mechanism of the target in the (Z)- direction

- The steering mechanism of the target with the (X)- direction

Image 11 presents a multi -target solution, in which several targets 72,73,74,75 and 76, produced by different materials, are situated on the same axle 71 ; these can steer the target's size (gauge) laterally in such a way that the new material comes into the sphere of influence of the laser beam on the circuit.

Image 11 shows a target application which rotates on its own central axis 70.

Provided that, for example, static optics 1 10-113 in accordance with the picture 14 is used, so the whole target cartridge can be oscillated, for example, within the plate 72 distance of the target laterally, for example, 7 5 mm of one target.

Figure 12 shows comprehensively what other functions can be placed into the volatization cartridge besides the actual laser beams which produce the ablation: A) 80, where two laser beams 83 and 82 pertaining two different wavelengths are directed, which are situated furthermore (even) against each other, so that a balanced spot area could be created.

It could be possible to direct separate laser beams 86, 87 from their own independent optics to the ionized plasma 85, which has come into existence in addition to the previous. As TJ2 demonstrates, the pulse energy should be 3-5 times as the ablation treshold of the substance; in addition to this, the other parameters pertaining to the volatization should also be in control well. Since the laser beams 86, 87 are concentrated on the already existing plasma, it is possible to influence the quality of the plasma 85 substantially, for example, by adding energy to it following the volatization episode. Bringing extra energy is advantageous, if any reaction gas is fed into the plasma such as 03, O2, nitrogen or any other gas, because ionized 85 cools anyway as it is expanded. As active gas components are added to the plasma, the plasma further freezes. By bringing extra energy to the plasma as required, we can differentiate two phases

(stages) separate (we can distinguish two different stages from each other); in other words, as the formation of the plasma and the modification of the plasma. Thus, we can create the most optimal evaporation (volatization) parameters for each of the stages separately.

The above mentioned new solution is noticeably easier to administer as two separate processes, because by merely creating the evaporation (volatization) parameters itself one can attempt to produce the optimal plasma, which ends up in the product surface as it is.

In the new method, it is possible to pertain to the plasma 85, 88 by a closed microwave energy source 90, by an electrically charged net, in other words, by the particle catcher or by creating electromagnetic fields of different degrees and movements using electromagnets or solid magnets such as neodymium magnets. It is also possible to pertain to the plasma by using Bias-DC voltage.

There are circumstances in which one must pertain to the atoms 92 situated in the surface of the substrate 93. This is the case with the production of pure diamond. In such an operation, it is economical (cost-efficient) if this laser beam is collimated and it is scanned by a full optical scanner, in which, for example, the KTN-crystal is included. Hence, we can maintain (keep up) the critical temperature just where it should be, on the revenue side of the plasma instead, so the whole plinth (base) is heated by the resistors, rather than the way done in the known methods.

In the new method, all the above mentioned different components are placed to the so-called volatization module fixedly, but the volatization module can still move in the x-y-direction. Figure 13 demonstrates, according to the new method, an ultra-fast wide laser scanner of one- or two-wavelength with a fully optical working width, whose scanning (scanner) is, for example, 100 kHz. In the picture, an application representing 100 a working width of 25 mm, but it is clear that the working width can always range from 100 μιη to 10 meter- working width; in other words, there is no theoretically maximum width. In practice, however, 1 meter is the rationally maximum width. In a industrially sophisticated application, it is possible to place the two fully optical wide scanners of the picture 13 against each other, so that both of the focusing optics 98 focus the laser beam to the same focal point (focus) creating a balanced spot area. Image 13 demonstrates the collimated laser beam, 94, which is directed to the fully optical scanner modulo, 96, fully optical in itself, via semipermeable optics. When from the other direction focused another, a second laser beam 95 to the selfsame semipermeable optics, it is possible to conduct (channel) two different laser beams, which have different wavelengths such as 532 nm and 1064 nm, to the same focal point. In addition, each of the laser beams can have their independent parameters, which are not dependent on each other.

Now the laser beams 94, 95 are directed to the fully optical scanner module (for example, a TN-type), so we can electronically (electrically) direct without the moving mechanical parts, to F-Theta lens pack 97 to the exit (output) optics via the focusing optics, finally to the target.

A scanner/scanning process with such an ultra-fast scanning frequency reaching up to 100 kHz devastates (overturns) the whole process, because precisely the scanning speed has been a big problem in high frequency laser systems (2-200 MHz repetition frequency). Of the conventionally used scanners, "galvo" scanners are quite slow, only the speed of the scanners, which are based on the mirrors rotating at a frequency rate of -10 Hz, is faster, but only at the rate of 1000 Hz; and the quality of the pulses produced by them is not at any point optimal or right. In addition, their efficiency is bad as a result of the changing of the mirror facet.

Image 14 demonstrates how four fixed focusing optic heads can be connected as a group, 110 and 112 to one wavelength, and 1 1 1 and 113 to another wavelength; so the focus of the laser beams 123 is a double function, in which two beams are for the target and two for the plasma, and partially optimal. In the picture, it is also demonstrated how the collimated laser beam 104 is directed to the focusing optics 105, 106 and via the mirror 107 to the terminal focusing optics 108, so that the exit area of the optics for the laser beam is small enough, for example, D=150 μπι -> 300 μιη, thus, the fluency of the laser beam can 'burn' the impurity off the exit way (the output point).

Image 15 shows how the volatization module according to the image 16 is placed in the mechanism, which is equipped with two linear modules, 1 15 in the y-direction and 114 in the x-direction. The laser beam 102 is divided into two using a semipermeable mirror, as two fully identical beams of 117 and 118, which then are directed against each other 111 and 113, so that a balanced pulse power in the entire spot area will be formed.

That one laser beam 102 is split as two identical laser beams 117 and 118, halves solely the pulse power; otherwise all the parameters are identical and in the system both pulses arrive at the same spot area at the same time.

Image 16 demonstrates the volatization module equipped with the 2+2 static optics, which is placed on top of the linear motor 114, so that it can move in the x-direction on top of the linear 114 in question. In picture 16, 2+2 system's direction and focusing optics 110, 112 and 111, 113 are directed in such a way that, for example, the 1. pair is focused to the target and the 2. pair is focused to the plasma. In the sample image, a pack is placed, in accordance with image 11 , made up of many different separate substances, separate disc-like targets 72-76, which is rotated by a separate motor.

Image 17 shows an application, which is divergent so far, but, in the image a linear motor system, 114 in accordance with the image 15, is being applied; two linear motors, below 119 and above 121, are synchronized with each other, so the focus optics of the laser beam 123 and the volatization target are always in the right place. This synchronization is carried out electronically (electrically).

Now the substrate, for example, a big sheet glass 118 can be thoroughly coated without the need to set up an extremely big transfer system of the substrate. Imra America US 2010/0000466 Al demonstrates that a) the laser beam is in place (still/motionless), b) the target is in place (still/motionless), c) the substrate moves in the direction of x-y-z. The problem is that, for example, typical sheet glass in the glass factory is 4x8m. in size, in other words, 32 m^A2. Thus, if the volatization optics is in place, the size of the vacuum chamber should be 2x length and 2x width, so as to be able to coat the entire sheet glass, in other words, the area of the chamber has to be 128 m^A2 .

It is possible to assume that manufacturing the required type of hardware brings about big problems.

In principle, the image 17 is the same volatization module idea as in the application, but the optics of the laser itself is separated from the volatization module and moved directly to the other side of the substrate.

Otherwise, the image in question, image 17, as a special application can have exactly the same components in it; as suggested in the solution according to the new method in terms of the remaining parts, in other words, separate laser beams are directed to the plasma 124 ja 125.

122 and 120 demonstrate that, although the laser optics 123 and the target module 120 move in the x-direction, the laser beam is always on the same point in the target.

Comparison 1

Comparison to the patent publication by Imra America US 2010/0000466 Al

The first difference is that, in it (the publication) the laser beam is focused 1) outside the vacuum chamber and 2) from a long distance. In the publication it is not argued per se whether the laser beam is directed a) straightaway to the target via the window, or b) through the workpiece, which, in our case, is a semiconductor disc / material transparent to the wavelength.

The conclusion in the publication is just right. In the USPLD- method, in which the lengths of pulses are 10 ps and below, the ablation is cold. Despite the fact that the ionized plasma is very much of high-energy, the properties of the target do not change, because there is no impact of heat. This is not the case in the PLD-method, in which the pulse is longer than the former (as it is called the 1).

Problems

In the patent claim 1 , it is demonstrated that the laser beam focused outside the vacuum chamber is directed through the substrate to the surface of the target, from which evaporizes (volatizes) ionized plasma on the surface of the substrate.

1) It has been notified that substrate is transparent to the wavelength being used, presumably 1064 nm, which is typical for fs-lasers. Still, always regardless of how transparent the material is, from the beam of the material do form reflections and diffusion, which diminish the power of the pulse essentially and deteriorates the quality of the pulse.

2) The situation grows still more problematic when the temperature of the substrate is raised to 600-900 °C degrees as the way it is presented, because the transparency of the substance diminishes as the temperature has gone up.

3) The laser beam is not scanned because the repetition frequency of the laser is not as 1000 Hz (1kHz), in other words, it could be used static focusing optics, which has directed the laser beam 1 circuit/s to the planar surface of the rotating target (to the largest surface).

4) It is not demonstrated any repetition frequency of 100 kHz or above, which could even be applied to the presented solution. Since the rotation speed of the target is far too low, so many pulses would hit the same point, and then, with the reported pulse energies of ~5J/cm^A2, this would destroy the target very quickly.

5) It is shown at one stage of the process the substrate can be too close (~30μπι) to the surface of the target, where the laser pulse ablates the material to the surface of the substrate in the form of ionized plasma.

The equation is extremely problematic because when the laser beam is focused outside the vacuum chamber, the distance is inevitably too long, typically over ~200 mm. Despite the fact that the laser beam is focused from 50 mm optics 20 μηι to the spot, the substrate too evaporates, if the pulse energy is 5 J/cm^A2 because the distance between the target and the substrate is so little.

6) In the new method no argument is brought on the fact that the direction of the laser beam a) through the substrate, or b) focusing the laser beam outside the vacuum chamber, because of that reason the quality of the pulse becomes non-existent on the surface of the target.

If it is still directed at an angle of 45°, as presented in the image, the fluence of the laser beam is not even in the entire area of the spot, but when vaporized other objects too become visible, like the ionized plasma, in other words, also particles appear and the substance melts. In the publication, there is no convincing solution presented to the problem of how the fluence of the laser pulse could have been distributed in the spot area.

Comparison 2

Comparison to the Lamsat-publication, University of South Florida

1) In the publication it is demonstrated that two laser beams of two different wavelengths are directed on the surface of the target. One laser beam operates with the wavelength of 10,6 μπι and it is continuously operating (CW) CO2 laser, which is used in the pulsed state. The other laser operates in the UV-area, an Eximer laser, which operates in the so-called the area of the pulse length.

2) It is presented that both of the mentioned laser beams are pulsed and they are directed to the same focus point on the surface of the target. It is reported that a better result is achieved this way, when compared to the one-laser-beam-only, regardless of the wavelength, pulse length or the repetition frequency being used to form the plasma. The difference from the new method is substantial. First of all, the presented method operates the same way as the thermal ablation, in other words, it is not the so-called cold ablation process. The new method is entirely based on cold ablation, in which the volatization mechanism is based on the electrostatic volatization (evaporation). Those pulse powers, pulse energies, pulse lengths and the repetition frequency are one at a time (singly) or together are of such class that the target is destroyed extremely fast. Particularly, if used two wavelengths, whose absorption is very good, the surface of the target is slivered (shattered) as a result of the thermal heat.

3) In this one too, the laser beam is focused from outside the vacuum chamber and the beams are directed in the focused form to the wavelengths in question via transparent windows to the target. In the new method this is not the way to follow for many reasons; but one reason is that the work space left for the substrate is too little as shown in the picture. In practice, the piece to be coated cannot be larger than 5" (~125 mm), because there is simply no maneuver space. Either the laser beams come from both sides of the substrate or the walls of the chamber alone is the obstacle for a larger piece. 4) In the new method, two laser beams are directed from opposite directions, but they represent the same wavelength and are synchronized to be at the same time on the spot. The purpose is to form a fully homogenous fluence for the spot area, which is not again possible, if the laser beam comes from only one direction, for example, at an angle of 45°. Therefore, two identical laser beams are needed so as to be able to compensate the change in the fluence in the spot area, which is caused by the coming angle of the laser. In the publication, the impact of the change in the fluency in the system in question; it cannot actually happen in this system because the pulse length for that is too long. The process is anyway uncontrollable in all aspects, since the thermal heat transition cannot be controlled because of the above mentioned reason. As volatized such, all the phases of the substance; plasma, molten material and particles move at the same time. The new method solves just this problem.

Claims

1. A coating and material production method, which is based on the application of picosecond, femtosecond and attosecond pulses a) in a vacuum, b) in a gas-pressurized mode, c) in liquid state or d) in the clean room standard; the repetition frequency of the pulses is between the span of 100 kHz and 10 GHz, with fiber reinforcement or semiconductor laser, which operate on the wavelength of the UV-visible-IR light, which is distinguishing (trademark of) in the sense that the laser beams are directed to a separate space a-d) with optic fibers or as a collimated beam and only inside this space is focused to the volatizing / processing material by self-cleansing optics

2. The method according to the patent claim 1 , in which self-cleansing is actualized, so optics or an area of optics, from which the laser beam exits (comes out), is distinguishing (trademark of) in the sense that the area is so small in its size that the fluency of the laser beam is always big enough and keeps, therefore, the surface always clean by volatization (steaming).

3. The method according to the patent claims 1 and 2, in which the area of the micro-optics, from which the laser beam to be focused exits the optics, is distinguishing (trademark of) in the sense that the exit surface of the beam of the focusing optics is kept from the target to be volatized/initiated within the distance of 0,2 - 20 mm.

4. The method according to the patent claims 1, 2 and 3, in which a fre- quency, as stable as possible, is created for the focusing area, is distinguishing (trademark of) in the sense that it is actualized by two opposite focusing optics, so their beams are placed accurately on top of each other.

5. The method according to the patent claims 1, 2,3 and 4, which is distin- guishing (trademark of) in the sense that to one optical system, from which the laser beam is focused, are placed two lasers pertaining significantly differ- ent wavelengths such as UV- and IR-wavelengths (for example,320 nm / 1064 nm).

6. The method according to the patent claims 1, 2,3,4, and 5, which is dis- tinguishing (trademark of) in the sense that the opposite laser beam pulses of the same wavelength are synchronized so as to strike the piece precisely at the same time.

7. The method according to the patent claims 1, 2,3,4,5, and 6, which is distinguishing (trademark of) in the sense that the opposite laser beam pulses of the same wavelength are synchronized so as to strike the piece in accordance with the adjustable difference of time.

8. The method according to the patent claims 1, 2, 3, 4, 5, 6, and 7, which is distinguishing (trademark of) in the sense that the power and energy of the synchronized pulses of opposite laser beams are independently adjustable from each other.

9. The method according to the patent claims 1, 2, 3, 4, 5, 6, 7, and 8, in which the production (output) is essentially elevated using a high repetition frequency and because of this reason a possibly fast scanning system and method are applied is distinguishing (trademark of) in the sense that it is actualized using an electronically operating active optical scanner, such as a scanner based on KTN-crystal or something else, whose scanning frequen- cies are over 10 kHz or the most economically over 100 kHz.

10. The method according to the patent claim 9, which is distinguishing (trademark of) in the sense that following the electronically operating active optical scanner is placed a lens system, which is in accordance with the claims 1-9, which enables the lineal scanning, for example, a scanning of 30 mm, on the surface of a flat or a cylindrical piece.

11. The method according to the above mentioned patent claims, which is distinguishing (trademark of) in the sense that an electronically operating active optical scanner is placed and applied as a static optical system, which is introduced in the previous patent claims.

12. The method according to the patent claim 1, in which it is meant to pertain to the ionized plasma coming into existence and is distinguishing (trademark of) in the sense that it is pertained to the plasma by a laser beam, which is in the CW-mode (continuously operating) .

13. The method according to the patent claims 1 and 12, which is distinguishing (trademark of) in the sense that it is pertained to the plasma by one or several laser beams, which are in the pulse mode and focused or colli- mated.

14. The method according to the patent claims 1, 12 and 13, which is distinguishing (trademark of) in the sense that it is pertained 0,001 mm to the plasma coming into existence always upto 20 mm, most optimally with a distance of 2 mm from the surface of the target in the direction of the plasma.

15. The method according to the patent claims 1 , 12, 13, and 14, which is distinguishing (trademark of) in the sense that pertaining to the plasma coming into existence is simple, because the volatization is actualized using static optics and it is pertained to the plasma within the distance of its emergence point a) by microwaves, b) by the electromagnetic field, c) by bias or d) by any combination of the previous.

16. The method according to the patent claims 1 and 15, which is distinguishing (trademark of) in the sense that it is pertained to the emerging plasma by spraying into it reactive gases, such as oxygen and nitrogen in various states, mixture gases such as C2H4, SF6, acetylene or another gas or gas mixture.

17. The method according to the patent claim 1, in which the temperature of the target being volatized, when needed, can be adjusted near the ablation treshold, for example, 0°C - 3000°C and the temperature is raised, for example, by laser beam, is distinguishing (trademark of) in the sense that the target is so-called a micro-target, whose volume is economically below 5 cm^A3, the most economically below lcm^A3 ant at its best below 0,5cm^A3.

18. The method according to the patent claim 17, which is distinguishing (trademark of) in the sense that to the target is directed a laser beam, which is pulsed and the length of the pulse is 999 ps or shorter than that, such as 100 ps, 50 ps, 5 ps, 1 ps, 500 fs, 100 fs, 10 fs etc.

19. The method according to the patent claims 1, 17 and 18, which is distinguishing (trademark of) in the sense that the target is round /rounded (rodlike) and it is rotated around its own axle.

20. The method according to the patent claims 1, 17 and 18, which is distinguishing (trademark of) in the sense that evaporation / volatization takes place on that surface of the target, which is the smallest in size/area, regardless of the shape or size of the target itself.

21. The method according to the above mentioned patent claims, which aims at coating large-sized pieces, is distinguishing (trademark of) in the sense that all the essential components in the system; optical components, the rotation and/or movement mechanism of the target with their actuators, the me- chanical components and other parts are placed on the plinth, which moves freely in the x-direction at least 2 mm, but typically, for example, 4 m with the help of the linear motion axle.

22. The method according to the patent claims 1-21, which is distinguishing (trademark of) in the sense that it is possible to place on the same linearly moving axle more, such as the volatization (steaming) module, which includes all the necessary optical and mechanical components needed for volatization.

23. The method according to the patent claims 1-22, which is meant for coating large areas, is distinguishing (trademark of) in the sense that one or several volatization modules are placed into the motion unit in more one degree of freedom, for example, x-motion = 4 m and y-motion = 10m.

24. The method according to the patent claims 1-23, which is distinguishing (trademark of) in the sense that it can be placed into the volatization module also an e-beam, an electron gun, a closed field magnetron sputtering device, a laser assisted pyrolysis unit (lasp = laser assisted pyrolysis), rf-plasma unit.