The smartphone shows screen produces system of medium accurate element laser

Of the smartphone popularize the growth that driving smartphone market, the market also is rising to the requirement of higher standards product, include to show screen dimension, resolution and battery life. Regard a crucial treatment as craft, anneal of accurate element laser (Excimer Laser Annealing, ELA) will be not brilliant silicon (A-Si) change is polycrystalline silicon (P-Si) , make electronic mobility raised hundreds times, can promote high end filmy transistor from this or show the density resembling element in screen. System of line beam of light can machine accurate element laser the liquid crystal of active matrix drive that smartphone and OLED TV place need displays screen (AMLCD) with active matrix face plate of organic glow diode (AMOLED) . In newest ELA system, provide by exquisite cylinder light send the line form light beam with even output (dimension is 750mm × 0.

4mm) , can realize fast anneal to the 8th acting face plate. The demand flat monitor of smartphone market (Flat Panel Display, FPD) the demand that manufacturer must face increasingly severe exacting, for example higher resolution, buildup contrast, faster noise is in season, reduce the power comsumption of monitor even at the same time. These requirements exceeded convention to display screen (backboard of the silicon that be not brilliant) function limit. On smartphone and flat computer, the resolution of high-powered indication screen can be amounted to 300 like element / inch above -- the Retina of IPhone 5 of malic mobile phone shows screen is a very good example; Backboard of electric conduction of this characteristic profit from has taller electronic mobility, and electric backboard comes from the silicon that be not brilliant just about. Technology of anneal of accurate element laser makes flat show screen manufacturing industry transforms from the silicon that be not brilliant polycrystalline silicon backboard. Because this one technology has the characteristic that microtherm machines, reason gets a name " microtherm polycrystalline silicon " (Low Temperature Polysilicon, LTPS) , it is applied to likewise make burgeoning OLED show screen and flexible indication screen. The polycrystalline silicon of low temperature of growth hang on of smartphone market shows in active matrix flat screen is medium, silicon is filmy transistor (TFT) the semiconductor foundation of matrix, and TFT matrix can resemble element undertaking controlling to what become independent severally. At first, filmy deposit is to pass traditional deposit technique to handle, use PECVD method on transparent glass base material for example. Gets silicon is filmy actually of dispute brilliant condition, show serious flaw, because this restricted its to apply at active matrix control LCD and OLED to display screen; And polycrystalline silicon can overcome this one limitation however, or in short, polycrystalline silicon has hundredfold to carry high stream child mobility. Above all, the electronic mobility of the silicon that be not brilliant is inferior, its block up transistor dimension becomes smaller. When the electronic mobility of polycrystalline silicon is only taller, smaller transistor just can offer bulk fill electric power enoughly. People expects TFT is smaller, because TFT can offer higher density resembling element or higher mouth rate,be, distinguish screen is brighter and electric efficiency is taller. Next, use polycrystalline silicon backboard, can realize drive and other circuit on indication screen directly, and reduce the amount of exterior signal connective, weight that reduces indication hold and thickness. The 3rd, because be not the vitreous material of brilliant silicon,pledge and ambiguous structure, in do not stabilize substantially; Because of this elapse as time, threshold value voltage can produce drift, bring about AMLCD especially the brightness of AMOLED indication screen produces a change. Because this is visible, polycrystalline silicon backboard is high-powered the perfect union with dependability; For high resolution AMLCD and the AMOLED that grow ceaselessly indication screen offers applicable TFT matrix. Because ELA is OK,undertake below the low temperature of 200 ℃ , anneal of laser of 308nm accurate element has become instantly screen to make in the first selection method of the polycrystalline silicon layer with effective preparation. Accordingly, in accurate element laser beam machining, can use common vitreous substrate, it is flexible even indication screen place uses can curve polymer base material. The pulse frequency that ELA means asks accurate element laser offers the tall pulse energy that is as high as 2 joule, hundreds of hertz and extremely tall energy stability, apply such as 1.

The VYPER laser of 2kW, 308nm and proper beam form a system, if pursue,1 is shown. Graph 1 crystal is random and perpendicular growth principle pursues (Zun Tu) with ELA craft medium typical grain mode (right graph) the means of backboard of Nextpage treatment polycrystalline silicon: Anneal of accurate element laser is in the ELA technology that uses extensively, 308 Nm allows the rectangular beam of light that molecular laser shoots, not only even and beam of light is OK plastic, in order to produce the light beam with line sectional form, make height of energy of beam of light distributings equably at whole beam of light sectional on. Line beam of light shoots Xiang Tu Fu directly the backboard of the silicon that be not brilliant, realize scanning of beam of light to move through athletic platform next (graph 1) . When scanning base material, the uniformity of line beam of light is 1%rms about, allow with same energy density (make an appointment with 500mJ/cm2) undertake in every position 10 to 20 irradiation. The silicon that be not brilliant can absorb radiation of laser of 308 accept rice effectively, absorb coefficient to be 6 × 106cm-1, this makes each pulse almost material of can complete melt. Make the silicon that be not brilliant filmy to be being absorbed of laser energy quickly the melt below temperature can be controlled in 1400 ℃ , form crystal grain when refrigeration next. Because the penetration of 308nm irradiation is lesser, have rice of a few accept only, width of together with short pulse is 50ns, make rock-bottom glass avoids be heated effect, and be heated temperature under temperature of its meet an emergency. Look from microcosmic angle, complete melt can promote the formation of crystal effectively, this is attributed to the characteristic that crystal is in from melt and the face of have a common boundary between solid silicon grows randomly along perpendicular direction. The line form length of line beam of light is the width of face plate of a base material or the half that are width normally. Use newest high energy laser, length of its line beam of light can amount to 750 millimeter, can realize the efficient anneal of pair of the 8th acting base material. The power of accurate element laser and stability progress need larger face plate size as a result of the market, anneal of this requirement LTPS uses longer, evener line beam of light. This is to drive high power 308nm to allow the main factor that molecular laser source develops continuously. Current, the accurate element laser in local anneal and application of other high accuracy mixes the layer ultraviolet program of government of beam of light, can offer come from tens of tile the average power limits of kilowatt class, if pursue,2 are shown. Graph system of laser of accurate member of company of 2 be concerned with and program of government of beam of light. In craft of anneal of microtherm polycrystalline silicon, need to shooting Xiang Gui the every laser pulse of backboard has strict control, and pulse energy stability is all in all laser parameter. Go 10 years inside, the usable power that the progress of this one domain makes 308nm follows molecular laser and stability get promoting considerably, can the face plate that large quantities of quantities machine large size, be based on the AMOLED of LTPS backboard especially, if pursue,3 are shown. Laser of accurate element of high power of graph 3 308nm is in aeriform service life period the stability inside. In the past 10 years, laser energy stability is in pulse standard deviation (Rms) with the peak - respect of sth resembling a net of peak energy bag already had marked improvement. As a result of the promotion of stability, the craft window of accurate element anneal can be matched better. Because this allows molecular laser anneal,the yield of 99% above is the big batch LTPS that is used in AMLCD and AMOLED TFT backboard in making. The laser power with higher recombine and bigger face plate, make the production value of LTPS flat manufacturing industry grew fourfold. Till recently, people has used 540 W to allow molecular laser to machine the 4th acting face plate with the line beam of light of 465 millimeter length, production gives a large number of AMLCD that are based on high-powered LTPS and AMOLED to display screen. The system of new-style VYPER /LB750 that rolls out at the beginning of 2011 applies extensively already at producing the spot now, anneal of accurate element laser already had succeeded to cross the 8th acting face plate from treatment of the 4th acting face plate. Laser of conclusion 308nm accurate element initiates sexual ground to go out for market treatment answer the AMLCD with faster, brighter, poorer rate and AMOLED tablet facility. Grow continuously as the market share that is based on LTPS to show screen and AMOLED display screen, manufacturer uses larger glass, so that make full use of dimensions economy, production gives the OLED TV face plate that market place needs. On the other hand, the manufacturing efficiency of ELA system gets great promotion, system of newest anneal of laser of beam of light of 750 millimeter line has applied in the mass production of the 8th acting large base material. CNC Milling