CN102623879A

CN102623879A - LD (laser diode) array multi-side-surface pump laser

Info

Publication number: CN102623879A
Application number: CN2012100904717A
Authority: CN
Inventors: 刘世文
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-03-31
Filing date: 2012-03-31
Publication date: 2012-08-01

Abstract

The invention provides an improved laser for macro machining of materials, wherein the laser comprises a direct-current source, a semiconductor laser diode array (named LDA), a YAG (yttrium aluminum garnet) crystal and a controller, wherein the direct-current source is used for driving the LDA; the controller is used for controlling the output current of the direct-current source; in operation, the luminous intensity of the LDA is controlled through controlling the output current value of the direct-current source by the controller, and finally the output energy of the laser is controlled; a high-power MOSFET (metal oxide semiconductor field effect transistor) is adopted for the controller; the LDA acts as a load and is connected to the drain electrode of the MOSFET in series; and the output current is controlled through controlling the voltage of a gate source. By adopting the laser provided by the invention, the multi-aspect applications of micro processing of a semiconductor circuit, invalid analysis, LED (liquid crystal display) maintenance and the like can be met, and the laser has the advantages of high efficiency, reliable performance, long service life and the like.

Description

The many side-pumped lasers of LD array

Technical field

The present invention relates to a kind of many side-pumped lasers of LD array that are used for the material microfabrication, can independently or cooperate the probe station system to use.

Background technology

Probe station is the very general equipment that uses in the semiconducter device testing.When chip design engineer or failure analysis engineer debug circuit, all can use the analysis probe platform usually.Probe station generally includes a base station, and the probe base platform is arranged on the base station, but places the probe base of three-dimensional regulation on the platform, an objective table, and objective table can be placed chip under test, a microscope stand, a microscope.Probe base can be regulated the electrode of probe base contact chip, carries out the test of chip signal.

Probe station is generally used for chip or the analysis of LCD liquid crystal display screen.Such device normally has the structure of multilayer material.Such as, integrated circuit normally is manufactured on the semi-conductor silicon chip, is made up of one or more layers polysilicon and one deck or multilayer passivation layer and one deck or multiple layer metal.

When surveying the chip metal electrode, need to remove the protection passivation layer of the superiors earlier to expose metal level with probe points.Remove passivation layer and can use ultrasonic wave, probe is scraped, plasma or chemical etching, and the FIB FIB, perhaps laser means realizes.Laser means is to realize the removal of passivation layer through microscope focusing pulse laser.Laser also can be used to cut off metal wire and revise the chip internal circuit.

Similarly, in large-scale LCD liquid crystal display screen manufacture process, line short is the phenomenon that possibly occur in the manufacture process.And large-scale LCD costs an arm and a leg, and the method for less expensive is that these location of short circuit are cut off reparation.Laser can be through focusing on the back with high-energy gasification location of short circuit material.Circuit material on the LCD liquid crystal display screen is ITO (a kind of transparent electrically-conductive film) normally, and electrode is Cr (chromium) normally.The CF filter of liquid crystal display screen also has flaw usually in manufacture process.Therefore, the defective of ITO, Cr electrode and CF filter also needs laser reparation.

The laser that some probe stations in the past comprise relatively is typically the Xenon xenon laser, for example: the laser of model SUSS XLC.This system adopts pulse xenon xenon lasing light emitter, through directly acting on device behind the microscope.This laser is exported 532 visible light wave range laser, so can pass general microscopical optical frames group.This single band laser is very complicated, and the xenon xenon laser must be installed with microscope together.This will make original huge probe station system complicated more, and very expensive.

And this laser has only green glow single band output, can only the cut-out material, limited its range of application.Which floor metal level is the common material of semiconductor have, and is insulating barrier between the metal level, long again one deck passivation layer protection after manufacturing finishes.Passivation layer is silica, silicon nitride and polysilicon normally.Most passivation layer penetrates for green glow.Therefore green laser depassivation layer can only be that metal level below the heating passivation layer makes the gasification of being heated of the passivation layer on upper strata.But this mode has only metal level below abundant, and is just feasible when being unlikely to metal level itself by gasification.For lower floor is that fine this rule of metallic circuit is infeasible.In addition, when semiconductor was analyzed, silicon can absorb green glow made silicon generate heat, thereby possibly cause the silicon damage.

Also has a kind of laser that multi-wave band laser output can be provided, for example: model New wave ezlaze3 laser.Its laser is the lamp pumping Nd:YAG laser of passive air cooling, adjustable Q, exportable 1064,532,355 and the 266nm wave band of laser.In addition, on the light path after the frequency multiplication, optical attenuator is set, is used for the energy of all output wave band of laser is regulated.As shown in Figure 1, optical attenuator 1 is made up of with multi-wavelength half slide 3 polaroid 2 that is positioned at light path.Half-wave plate 3 is tuning with multiwave laser generation, and polaroid 2 is positioned at rotatable mechanism 4 and regulates the output energy.

But; Laser adopts lamp pumping Nd:YAG laser, and can produce following problem: the lamp pumping is that the light that utilizes krypton lamp or xenon lamp to send comes pumping, and the spectrum of the light that krypton lamp sends is wider; A big slightly peak value is just arranged at the 808nm place; The light of other wavelength all becomes useless heat at last and has dissipated, so the conversion efficiency of its lamp pump laser is much lower with respect to semiconductor pumped, approximately has only about 3%; The energy major part of sending of pumping lamp has converted heat energy to, has caused great energy waste.Xenon lamp has same inefficiency problem as pumping source.

In addition; Adopt optical attenuator to regulate the energy of laser output; Can produce following problem: research shows; When multi-wavelength half slide optical thickness was the odd near first-harmonic, two frequencys multiplication, frequency tripling, these four laser half-wavelengths of laser of quadruple, this multi-wavelength half slide can be regulated all these four laser.But optical attenuator can not all guarantee high transmitance to first-harmonic, two frequencys multiplication, frequency tripling and laser of quadruple, and for the laser of some wavelength, its attenuation is too big, can cause very big energy loss.For example, when the attenuator conducting, the optics rank suprasil eyeglass of 0.77901mm thickness can pass through 100% quadruple, 99.4% frequency tripling, 98.6% 2 frequency multiplication, 89.3% fundamental frequency; 0.0865mm, 100% quadruple, 89% frequency tripling, 100% 2 frequency multiplication, 62% fundamental frequency.0.3091mm, 100% quadruple, 98% frequency tripling, 77% 2 frequency multiplication, 99% fundamental frequency.0.5564mm, 100% quadruple, 85% frequency tripling, 87% 2 frequency multiplication, 96% fundamental frequency.0.9274mm, 100% quadruple, 85% frequency tripling, 100% 2 frequency multiplication, 88% fundamental frequency.

Therefore, a kind of more economically, easy to use, efficient, energy-conservation laser of needs.

Summary of the invention

We find through experiment; There is positive relationship as shown in table 1 in it through the size of current of semiconductor diode and size of laser output energy during semiconductor diode pump source Nd:YAG laser works; Therefore, can reach the purpose of the size of regulating laser output energy through the size of current of control semiconductor diode.

In view of the above, the invention provides a kind of modified model laser that is used for the material microfabrication, comprise DC source, semiconductor laser diode array (calling LDA in the following text) and Nd:YAG crystal; Wherein, DC source is used to drive said LDA, it is characterized in that: also comprise controller, be used to control the output current of said DC source; During work

Table 1: electric current and energy corresponding relation:

Electric current (A)	Laser energy (mJ)
		50	0.9
52	1.2
		54	1.9
56	2.4
		58	2.9
60	3.2
		62	3.5
64	3.8
		66	4.0
68	4.3
		70	4.6
72	4.8

The output current value of controlling said DC source through said controller is finally controlled the output energy size of laser to control the luminous intensity of said LDA.

Said controller adopts powerful MOSFET pipe, and said LDA is connected on the MOSFET drain D as load, controls output current through the control gate source voltage.

Said laser also comprises relay protection circuit, is used to protect LDA.Said relay protection circuit can also comprise and presets load.

According to laser of the present invention, said controller can be controlled said DC source, makes the electric current of its output 0 to 73A.

According to laser of the present invention, said DC source can also be connected to clock unit, is used to carry external timing signal to trigger said DC source.Trigger DC source after the clock signal that DC source receive clock unit sends, make laser by clock frequency output laser.Laser pulse output number of times and frequency be can regulate like this, laser cutting precision and operating rate effectively controlled.And help reducing the number of times of direct contact laser, help prolonging the useful life of laser.

During work, DC source drives said diode laser matrix (LDA) and sends continuous light source or the light-pulse generator with certain wavelength, with excitation Nd:YAG crystal.Said controller can the said diode laser matrix of controlling and driving (LDA) current value, thereby control its luminous intensity, finally reach the purpose of the output energy size of control laser.

Adopt laser according to the invention can satisfy many-sided application such as the little processing of semiconductor circuits, failure analysis, the maintenance of LCD liquid crystal display screen; And have the following advantages: 1, efficient is high: semiconductor diode sends the laser of 808nm wavelength fixing, that absorbed by laser crystal, and the light light conversion efficiency can significantly reduce the heat that operating cost and lamp pumping light modulation pump are produced up to more than 40%; Bring lifting 2, dependable performance, the life-span of laser output upper energy limit value and laser works upper frequency limit long thus: the life-span of semiconductor light-emitting-diode is longer than photoflash lamp greatly; Reach more than 15000 hours, the life-span of photoflash lamp has only 300-1000 hour, and the pump energy good stability of semiconductor light-emitting-diode; Than the excellent energy level of flash lamp pumping; Dependable performance can be made into full curing device, and service life is long; Maintenance free especially is suitable for large-scale production line.3, output beam quality is good: by the semiconductor light-emitting-diode pumping, the conversion efficiency of exciting light and laser is high, has reduced the thermal lensing effect of working-laser material, has improved the output beam quality of laser greatly.4, energy loss is less: adopt the adjusting to the semiconductor led current to realize the decay of output laser energy, avoided optical attenuator to first-harmonic, two frequencys multiplication, energy loss that frequency tripling and laser of quadruple produced, practiced thrift cost.5, has the external trigger function:, therefore, can realize the external trigger function of laser owing to can pass through the Current Control semiconductor light-emitting-diode.

Description of drawings

Accompanying drawing 1 is the structure chart of the optical attenuator that laser adopts in the prior art;

Accompanying drawing 2 is laser structure figure of the present invention;

Accompanying drawing 3 is embodiment block diagrams

of laser according to the invention

Embodiment

Below in conjunction with accompanying drawing the present invention is further described in detail.

As shown in Figure 2, laser 100 of the present invention comprises the Nd:YAG crystal 101 that the LD array triggers, semiconductor laser diode array (calling LDA in the following text) 102, and DC source 103 is used for to LDA102 power supply being provided.LDA102 sends continuous light source or the light-pulse generator with certain wavelength and intensity, with exciting laser operation material Nd:YAG crystal 101, produces the laser with certain energy.Controller 104 is used to control the output current size of DC source, and then the energy of control laser output laser.Other assemblies of laser are not shown.

As shown in Figure 3, the specific embodiment block diagram of Circuits System of the present invention can comprise following part:

(1) controller 104

Controller 104 is made up of current sense resistor 309, MOSFET control valve 308, amplifier 306, comparator 307 and load current initialization circuit 305.Load current initialization circuit 305 produces a stable benchmark voltage, and input comparator 307.The output current of DC source 103 is detecting resistance 309 generation sampling voltages, and input comparator 307 compares with reference voltage after amplifier 306 amplifies.According to comparative result the output current of DC source 103 is adjusted then, whole closed loop feedback system is in the dynamic equilibrium, to reach the purpose of stablizing output current.

Said controller 104 adopts powerful MOSFET control valve 308.Come control flows to cross the load current of its drain electrode through control MOSFET control valve 308 gate source voltages.Said LDA is connected on the MOSFET drain D as load.We detect resistance 309 at one of the source series of MOSFET control valve 308, are used for sampling feedback control.The voltage that detects resistance 309 is amplified through amplifier 306, mate with input voltage.Input control voltage has just been set up corresponding relation with the electric current of the LDA that flows through like this, can adapt to the operation needs of LDA.

(2) switching circuit 302

Switching circuit 302 is made up of clock signal, switch mosfet pipe and drive circuit thereof, under the effect of clock signal as the master switch of above-mentioned DC source 103.If laser breaks down in running, perhaps carry out operation out of service, just require system can cut off the electric current that injects the LDA array automatically immediately.We adopt a switch mosfet pipe as switch, make it be operated in saturation conduction state or the next closed or turn-off current resource loop of cut-off state through the gate source voltage of controlling the switch mosfet pipe.And the clock of the having no way of input control signal that has of the gate source voltage of switch mosfet pipe determines.

(3) relay protection circuit 303

Relay protection circuit 303 is made up of relay protection circuit and relay drive circuit.Can make output current in the LDA load with preset between the load and switch in system start-up with when quitting work, in order to avoid the LDA array receives surge impact and damages.Static surge current and electrical network impact etc. all can cause permanent damage or shorten its useful life by the noise spectra of semiconductor lasers array.Before the stable working state waveform of DC source 103 met the demands, LDA broke away from the current source loop and inserts and preset load.Only after the stable working state waveform of DC source meets the demands, could allow to insert LDA, start laser works.

Laser of the present invention, structure are compact more, and power/energy stablizes＜3%, long service life, and electro-optical efficiency can provide continuously or pulse laser up to more than 20%, is with a wide range of applications.

Claims

1. a laser that is used for the material microfabrication comprises DC source, semiconductor laser diode array and Nd:YAG crystal, wherein; DC source is used to drive said semiconductor laser diode array; It is characterized in that: also comprise controller, be used to control the output current value of said DC source, during work; The output current value of controlling said DC source through said controller is finally controlled the output energy size of laser to control the luminous intensity of said semiconductor laser diode array.

2. laser as claimed in claim 1; It is characterized in that: said controller adopts the MOSFET control valve; Said semiconductor laser diode array is connected on as load in the drain electrode of MOSFET control valve, controls output current through the gate source voltage of controlling said MOSFET control valve.

3. laser as claimed in claim 2 is characterized in that: said laser also comprises relay protection circuit, is used to protect semiconductor laser diode array.

4. laser as claimed in claim 3 is characterized in that: said relay protection circuit comprises also and presets load that said output current switches said presetting between load and the semiconductor laser diode array each other.

5. laser as claimed in claim 4 is characterized in that: said controller can be controlled said DC source, makes the electric current of its output 0A to 73A.

6. laser as claimed in claim 5 is characterized in that: said DC source also is connected to clock unit, is used to carry external timing signal to trigger said DC source.