CN103026297A - Photomask correcting method and laser processing device - Google Patents
Photomask correcting method and laser processing device Download PDFInfo
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- CN103026297A CN103026297A CN2011800369078A CN201180036907A CN103026297A CN 103026297 A CN103026297 A CN 103026297A CN 2011800369078 A CN2011800369078 A CN 2011800369078A CN 201180036907 A CN201180036907 A CN 201180036907A CN 103026297 A CN103026297 A CN 103026297A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/50—Mask blanks not covered by G03F1/20 - G03F1/34; Preparation thereof
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/68—Preparation processes not covered by groups G03F1/20 - G03F1/50
- G03F1/72—Repair or correction of mask defects
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/066—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms by using masks
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/54—Absorbers, e.g. of opaque materials
Abstract
The present invention enables correction of a photomask halftone pattern with very low transmittance. A CVD film is formed on a portion to be corrected of the halftone pattern of the photomask (2) using a source gas comprised of chrome carbonyl gas and an ultra-violet laser beam with an irradiation energy density per pulse of 40 mJ/cm2 or more, or an irradiation power density of 1 MW/cm2, emitted from a CVD processing laser oscillator (11) in which the Q-switch frequency is set within a range of 1 Hz to 1 kHz. The present invention can be applied to a laser processing device for correcting a photomask, for example.
Description
Technical field
The present invention relates to photomask modification method and laser processing device, especially relate to photomask modification method and the laser processing device of situation of the correction of the halftone pattern that is applicable to carry out photomask.
Background technology
At present, as a kind of use laser CVD (Chemical Vapor Deposition) method (for example, with reference to patent documentation 1) of the modification method of the defective part of photomask.
In addition, at present, in the film formation process of the cvd film when the defective part correction of the halftone pattern of photomask, the 4th higher harmonics of example such as Q-switch Nd:YLF laser or Q-switch Nd:YAG laser (FHG, wavelength 263nm or 266nm).And (for example, the irradiation energy density of each pulse is 10～30mJ/cm by reducing laser intensity
2), reducing unstrpped gas is the concentration of chromium carbonyl gas, can roughly according to the quantity delivered restriction film forming speed of unstrpped gas, pile up simultaneously cvd film.
Thus, the distribute impact of the intensity distributions be difficult to be subject to laser of the transmissivity of cvd film, can the film forming transmissivity uniform cvd film roughly.In addition, because film forming speed low (for example, about 0.5nm/s), so that the inching of transmissivity becomes is easy.
In addition, the Q-switch frequency setting is at the 2～4kHz that on average is output as maximum of for example laser.
Patent documentation 1:(Japan) JP 2007-232964 communique
But, the relation of the transmissivity T of cvd film and thickness d is used reflectivity R, the absorption coefficient of cvd film, obtain (wherein, in fact because the impact of the multiple interference that generates at cvd film is arranged, so transmissivity α is according to the value increase and decrease of obtaining with formula (1)) by following formula (1).
T＝（1－R）×e
-αd（1）
According to formula (1), with regard to transmissivity T, thickness d is thicker, and it is less, and absorption coefficient is less, and it is larger.
The cvd film that obtains by above-mentioned existing film build method is with chromium oxide III(Cr
2O
3) be principal ingredient.Cvd film take chromium oxide III as principal ingredient is with respect to FPD(Flat Panel Display) absorption coefficient of the exposure wavelength (the bright line i line (365nm) of mercury, h line (405nm), g line (436nm)) of the photomask of usefulness is low.Therefore, for as the needed thickness d of the transmissivity T of target thickening.
For example, be approximately 9 * 10 with respect to the absorption coefficient of the i line of the cvd film take chromium oxide III as principal ingredient
3Cm
-1About, be 40% in order to make the transmissivity with respect to the i line, needed thickness is made as approximately 90nm, in order to be made as 10%, needed thickness is made as approximately 250nm.
On the other hand, when the thickness of cvd film increases, when the cvd film of film forming carries out shaping during to the correction of halftone pattern by ZAP processing, can generate crackle, after the operations such as cleaning in cvd film may peel off.Therefore, to be difficult to be applicable to respect to i line transmissivity be in the correction of the halftone pattern below 40% to the film build method of above-mentioned existing cvd film.
Summary of the invention
The present invention foundes in view of this situation, can carry out the correction of halftone pattern of the photomask of lower transmissivity.
The photomask modification method of one aspect of the present invention carries out the correction of photomask, it is characterized in that, uses the irradiation energy density of each pulse of penetrating from the laser oscillator of Q-switch frequency setting in the scope of 1Hz to 1kHz to be 40mJ/cm
2Above or irradiation power density is 1MW/cm
2Above Ultra-Violet Laser and the unstrpped gas that is made of the chromium carbonyl gas are at the retouch film forming cvd film of the halftone pattern of described photomask.
In one aspect of the invention, at the membranous cvd film of the retouch film forming metal chromium of the halftone pattern of photomask.
Therefore, can carry out the correction of halftone pattern of the photomask of lower transmissivity.
This laser oscillator is by for example CW(Continuous Wave) the Q-switch Nd:YLF laser of excitation consists of.This Ultra-Violet Laser for example is the laser of the 4th higher harmonics (FHG, oscillation wavelength 263nm) of Q-switch Nd:YLF laser.
In this photomask modification method, can use pulsewidth as below the 40ns and irradiation power density be 1MW/cm
2Above Ultra-Violet Laser, or the irradiation energy density of using pulsewidth to surpass 40ns and each pulse surpasses 40mJ/cm
2Ultra-Violet Laser.
Thus, be not limited to the pulsewidth of Ultra-Violet Laser, can carry out the correction of halftone pattern of the photomask of lower transmissivity.
The laser processing device of an aspect of of the present present invention, carry out the correction of photomask, it is characterized in that, possesses the Q-switch laser oscillation apparatus that makes the Ultra-Violet Laser vibration, to near supply with the unstrpped gas that is consisted of by the chromium carbonyl gas retouch of the halftone pattern of described photomask material gas supply device, control the irradiation energy density of each pulse of the Q-switch frequency of described Q-switch laser oscillation apparatus and Ultra-Violet Laser and the laser control apparatus of irradiation power density, the Q-switch frequency setting of described Q-switch laser oscillation apparatus in the scope of 1Hz to 1kHz, is set in 40mJ/cm with the irradiation energy density of each pulse of Ultra-Violet Laser
2Above or the irradiation power density of Ultra-Violet Laser is set in 1MW/cm
2Above, shine described Ultra-Violet Laser to retouch, generate cvd film at described retouch.
In one aspect of the invention, at the membranous cvd film of the retouch film forming metal chromium of the halftone pattern of photomask.
Therefore, can carry out the correction of halftone pattern of the photomask of lower transmissivity.
This Q-switch laser oscillation apparatus is by for example CW(Continuous Wave) the Q-switch Nd:YLF laser of excitation consists of.This Ultra-Violet Laser is the laser of the 4th higher harmonics (FHG, oscillation wavelength 263nm) of for example Q-switch Nd:YLF laser.This material gas supply device by for example gas cell and unstrpped gas supply with, exhaust unit consists of.This laser control apparatus is made of for example computing machine or various processor.
According to an aspect of the present invention, can revise the halftone pattern of photomask.Especially according to an aspect of the present invention, can carry out the correction of halftone pattern of the photomask of lower transmissivity.
Description of drawings
Fig. 1 is the block scheme that an embodiment of laser processing device of the present invention is used in expression;
Fig. 2 is the chart of relation of the average transmittance of the irradiation time of expression CVD laser and cvd film;
Fig. 3 is the chart of the irregular relation of the expression average transmittance of cvd film and transmissivity;
Fig. 4 is for the flow process of explanation by the photomask correcting process of laser processing device execution;
Fig. 5 is the figure that schematically shows the example of the front photomask of halftone pattern correction;
Fig. 6 is the figure of the example of the photomask after schematically showing halftone pattern and removing;
Fig. 7 is the figure that schematically shows the example of the photomask after retouch makes the cvd film film forming;
Fig. 8 is the figure that schematically shows the example of the photomask after the cvd film shaping of film forming.
Symbol description
1 laser processing device
2 photomasks
11 CVD processing laser oscillator
12 Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system
13 ZAP processing laser oscillator
14 Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system
15 variable gaps
16 imaging processing opticals system
The 16a object lens
The 16b micropositioner
17 gas cell
18 unstrpped gases are supplied with, exhaust unit
24 probe light sources
25 transmitted intensity analyzers
26 control parts
Embodiment
Below, describe being used for implementing mode of the present invention (below, be called embodiment).In addition, illustrate by following order and undertaken.
1. embodiment
2. variation
(1. embodiment)
(configuration example of laser processing device)
Fig. 1 is the block scheme that an embodiment of laser processing device 1 of the present invention has been used in expression.
CVD processing with laser oscillator 11 for example by CW(Continuous Wave) the Q-switch Nd:YLF laser of excitation consists of, vibrate and penetrate the laser (below be also referred to as CVD laser) of the 4th higher harmonics (FHG, oscillation wavelength 263nm).
Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 12 is be used to the intensity distributions that makes the CVD laser by variable gap 15 uniform optical system roughly.For example, Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 12 enlarges the beam diameter of CVD laser by optical beam expander, by making the little light beam central portion of intensity difference to the opening incident of variable gap 15, make the intensity distributions equalization of the direction in space of the CVD laser by variable gap 15.In addition, Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 12 utilizes light modulator etc. that laser beam is swung, and makes the intensity distributions equalization of the time orientation of the CVD laser by variable gap 15.In addition, laser illumination intensity homogenising optical system 12 possesses the optical attenuator for the irradiation power density of regulating CVD laser.
ZAP processing for example is made of the Q-switch Nd:YLF laser of pulse excitation with laser oscillator 13, the laser that vibrate, ejaculation repetition oscillation frequency is the following third high harmonic wave (THG, oscillation wavelength 355nm) of 50Hz (below, be called ZAP laser).Use as ZAP laser by the laser with this black light, bring damage for the glass substrate of photomask 2, can realize fine correction processing.In addition, this wavelength is near the laser of the black light the 355nm, and the laser of processing usefulness as ZAP generally is used in the repair apparatus of the correction of carrying out photomask all the time.
Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 14 has the formation same with Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 12, makes the intensity distributions of the direction in space of the ZAP laser by variable gap 15 and time direction roughly even.In addition, Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 14 possesses the optical attenuator for the irradiation power density of regulating ZAP laser.
In addition, below, in the situation that do not need to distinguish especially CVD laser and ZAP laser, be called simply laser.
It is one group blade that variable gap 15 is provided with two groups two, and the interval of the blade by regulating each group can change the size of the opening of rectangle.In addition, variable gap 15 has whole around mechanism that optical axis rotates.
The imaging processing optical is 16 to be the optical system that make on the surface of photomask 2 by the laser imaging of variable gap 3.The imaging processing optical be 16 such as by object lens 14a, imaging len (not shown), dichroic filter (not shown), form the light path of laser catoptron (not shown), measure the formations such as Laser output analyzer (not shown) by the output of the laser behind the variable gap 15.In addition, the imaging processing optical be 16 possess for the velocity sweeping with regulation on photomask 2 be the micropositioner 16b that point of irradiation makes object lens 16a fine motion according to the picture of the opening of the variable gap 15 of laser.
Unstrpped gas is supplied with, exhaust unit 18 is supplied with carrier gas and Purge gas to the processing department of photomask 2.Unstrpped gas is supplied with to the processing department of photomask 2 by carrier gas.Purge gas is removed air from the processing department of photomask 2.In addition, unstrpped gas is supplied with, exhaust unit 18 possesses the suction inlet that the mode of not leaking to the outside with unstrpped gas sucks, and supplies with the gas that sucks to gas cell 17.Thus, near the space the processing department of photomask 2 is held in the unstrpped gas environmental gas.And, remain near the space the processing department of photomask 2 under the state of unstrpped gas atmosphere gas, in processing department, pile up cvd film in processing department by the CVD Ear Mucosa Treated by He Ne Laser Irradiation.
In addition, unstrpped gas is supplied with, exhaust unit 18 possesses transmission laser, observe illumination light and the luffer boards of the light of popping one's head in.Purge gas also plays the effect that prevents that these luffer boards from being processed by CVD.
Probe light source 24 penetrate based on the control of control part 26 exposure of carrying out photomask 2 exposure machine optical source wavelength or near its light (probe light) of wavelength.The probe light that penetrates from probe light source 24 by the imaging processing optical be 16, unstrpped gas is supplied with, the luffer boards of exhaust unit 18 are to photomask 2 irradiations.See through the probe light of photomask 2 by transillumination lens 22 optically focused, to 25 incidents of transmitted intensity analyzer.
Transmitted intensity analyzer 25 is measured the probe light intensity that sees through photomask 2, supplies with the signal of expression measurement result to control part 26.
In addition, based on the control of control part 26, mobile transillumination 21 and transmitted intensity analyzer 25 selectively arrange any in transillumination 21 and the transmitted intensity analyzer 25 on the optical axis of transillumination lens 22.
In addition, it is 16 micropositioner 16b that control part 26 is controlled to as processing optical, regulates the sweep velocity of point of irradiation.In addition, control part 26 control gas cell 17 are regulated the concentration of unstrpped gas and the flow of Purge gas and carrier gas.In addition, control part 26 control XY platforms 20 make photomask 2 position movement in the horizontal direction.In addition, control part 26 carries out the setting of the position of transillumination 21 and transmitted intensity analyzer 25.In addition, control part 26 is based on the measurement result of the probe light intensity of transmitted intensity analyzer 25, obtains the transmissivity of the halftone pattern etc. of photomask 2.
(the CVD processing conditions during the halftone pattern correction)
At this, in laser processing device 1, the CVD processing conditions during to the defective part of the halftone pattern of revising photomask 2 is inquired into.
In order to prevent cracking when the cvd film of film forming carries out shaping during to the correction of halftone pattern by ZAP processing, making with respect to black light is that the large and film forming thickness of the absorption coefficient of ZAP laser is that thin cvd film gets final product.
In order to obtain large with respect to the near ultraviolet optical absorption coefficient and thickness is thin cvd film, with the white defect correction of existing dual masks the time, under the identical condition, to carry out CVD processing and get final product.That is, compare during with above-mentioned existing halftone pattern correction, increase the concentration of unstrpped gas, increase the intensity of CVD laser, the membranous cvd film that the character of film forming metal chromium is stronger gets final product.
For example, with the Q-switch frequency setting at 2kHz(pulse wide (half amplitude) 40ns roughly), the average irradiation power density of CVD laser is set in 80～200W/cm
2, the irradiation energy density of each pulse is set in 40～100mJ/cm
2, irradiation power density (the irradiation energy density of=each pulse/laser pulse width of cloth (half amplitude)) is set in 1～2.5MW/cm
2, by suitably regulating the concentration of unstrpped gas, the membranous cvd film of the very large metal of coefficient that can be absorbed.
In fact, in the white defect correction of existing dual masks, piling up absorption coefficient under this CVD processing conditions is 3 * 105cm
-1About the cvd film of (about OD3 about the thickness 150nm of (about transmissivity 0.1%)).
Thus, even transmissivity reduces, also can film forming add the cvd film that does not crack after man-hour and the processing at ZAP.Easily film forming is approximately 2.3 * 10 with respect to the absorption coefficient of i line for example
5Cm
-1Above, namely the transmissivity with respect to the i line is 40%, and thickness is the following cvd film of 40nm.And, can carry out the correction of the defective part of the low halftone pattern of transmissivity.
In addition, as mentioned above, because the absorption coefficient of the exposure wavelength (i line, h line, g line) of the photomask that the cvd film take the chromium oxide III of film forming under existing CVD processing conditions as principal ingredient is used with respect to FPD is low, so transmissivity significantly changes because of exposure wavelength.Relative with it, under this CVD processing conditions the cvd film of film forming because of membranous near crome metal, so roughly the same with respect to the absorption coefficient of i line, h line, g line, can reduce the poor of transmissivity that the exposure wavelength difference causes.
But under this CVD processing conditions, the stackeding speed of cvd film accelerates to about 100nm/s, is difficult to carry out the control of thickness.In addition, the absorption coefficient of cvd film is that ZAP laser is large than black light not only, and also larger than i line, h line, g line, and only thickness is different, and transmissivity significantly changes.Therefore, be difficult to the transmissivity of cvd film is set in the value of hope, the transmissivity that the membrane thickness unevenness in the cvd film causes is irregular can be increased.
Therefore, below, inquire into reducing the irregular method of transmissivity.
Fig. 2 is illustrated in to scan approximately 40ns of pulsewidth (half amplitude) on the quartz base plate, and the irradiation energy density of each pulse is 40mJ/cm approximately
2(irradiation power density is 1MW/cm approximately
2) CVD laser point of irradiation and pile up in the situation of cvd film, the irradiation time of the CVD laser when making Q-switch frequency and scan speed change and cvd film are with respect to the chart of the example of the measurement result of the average transmittance of i line.In addition, the irradiation time of CVD laser is obtained by the size ÷ sweep velocity of the point of irradiation of direction of scanning.In addition, the transverse axis of Fig. 2 represents that (unit: second), the longitudinal axis represents average transmittance (unit: %) to irradiation time.
Fig. 3 is the chart of the example of the irregular measurement result of the transmissivity with respect to the average transmittance of i line and direction of scanning under the expression condition identical with Fig. 2.In addition, the maximal value of the irregular transmissivity by the direction of scanning of transmissivity and the difference of minimum value represent.In addition, the transverse axis of Fig. 3 represents that (unit: %), the longitudinal axis represents the irregular (unit: %) of transmissivity to average transmittance.
As can be seen from Figure 2, the Q-switch frequency is lower, and the needed irradiation time of average transmittance that reduces cvd film is longer.That is, the Q-switch frequency is lower, and the stackeding speed of cvd film is slower.For example, with the Q-switch frequency be 2kHz situation relatively, the Q-switch frequency is in the situation of 1kHz, the stackeding speed of cvd film is approximately 1/2, the Q-switch frequency is in the situation of 0.5kHz, the stackeding speed of cvd film is approximately 1/4.Thus, the control of thickness becomes easily, can obtain the cvd film of the transmissivity of more approaching hope.
In addition, as can be seen from Figure 3, the Q-switch frequency is lower, and the transmissivity of direction of scanning is irregular fewer, and the homogeneity of the thickness of direction of scanning improves.As mentioned above, the Q-switch frequency is lower, and the stackeding speed of cvd film is slower, for the irradiation time of the needed CVD laser of cvd film of the transmissivity that obtains wishing longer.Its result, by will be according to the vibration of the CVD laser in short time time of penetrating, the change of sweep velocity, the change equalization of output intensity, with the uniform film thickness in the cvd film, thereby it be irregular to improve transmissivity.In addition, the Q-switch frequency reduces, the time interval (interval of CVD laser) of carrying out the CVD Ear Mucosa Treated by He Ne Laser Irradiation is when increasing, the surface excess of the molecular raw material gas of the leading section of cvd film is saturated in the meantime, therefore, the formation of examining of growing up is stably carried out, and the stackeding speed of cvd film is stable, and this also is to improve an irregular main cause of transmissivity.
Measurement result according to Fig. 3, transmissivity is irregular be the scope of the average transmittance below 4% in the situation that the Q-switch frequency is 2.0kHz, be below 20%, relative with it, in the situation that the Q-switch frequency is 1.0kHz, 0.5kHz, be about respectively below 40%, below 49%.Therefore, the permissible level that transmissivity is irregular is made as 4%(± 2%) time, as long as with the Q-switch frequency setting below 1.0kHz, just can revise the halftone pattern of the transmissivity less than 40% that can not revise at present and pile up enough cvd films.
In addition, at this moment, under arbitrary Q-switch frequency, be that 40% thickness is below the 40nm with respect to the average transmittance of i line, be that 10% thickness is below the 100nm with respect to the average transmittance of i line.This expression cvd film is approximately 2.3 * 10 with respect to the absorption coefficient of i line
5Cm
-1Above.
In addition, even must be higher than 1kHz with the Q-switch frequency setting, by reducing the irradiation power density of raw gas concentration or CVD laser, can reduce the stackeding speed of cvd film, and prolong the irradiation time of CVD laser.But during owing to raising Q-switch frequency, the formation of the growth nuclear of the leading section of cvd film is unstable, and therefore, transmissivity is irregular can be worsened.
In addition, the measurement result of Fig. 2 and Fig. 3 is the about situation during 40ns of pulsewidth of CVD laser, in addition, to the situation except 40ns for example pulsewidth different situation in the scope from about several ns to 100ns inquire into.
Below, will be made as Δ T for the ascensional range of the surface temperature of the quartz base plate of each pulse of the needed CVD laser of membranous cvd film of obtaining metal.In addition, below, the thermal diffusion length (κ in the cvd film
CVD* τ)
1/2(κ
CVDBe the heat-conduction coefficient of cvd film, τ is the pulsewidth of CVD laser) enough larger than thickness, therefore, cvd film is identical temperature variation.In addition, below, will be approximately C to the heat conduction of quartz base plate
g* ρ
g* (κ g * τ)
1/2* Δ T(C
gBe the specific heat of quartz base plate, ρ
gBe the density of quartz base plate, κ
gHeat-conduction coefficient for quartz base plate).So Δ T is expressed from the next.
ΔT＝P×τ/（C
CVD×ρ
CVD×d＋C
g×ρ
g×（κ
g×τ）
1/2）（2）
Wherein, P represents the irradiation power density of CVD laser, C
CVDThe specific heat of expression cvd film, ρ
CVDThe density of expression cvd film, d represents the thickness of cvd film.
Thus, the irradiation power density P, the irradiation energy density P * τ that obtain the ascensional range Δ T of identical surface temperature are following formula.
P＝ΔT×（C
CVD×ρ
CVD×d/τ＋C
g×ρ
g×（κg/τ）
1/2）（3）
P×τ＝ΔT×（C
CVD×ρ
CVD×d＋C
g×ρ
g×（κ
g×τ）
1/2）（4）
According to formula (3) and formula (4) as can be known, with respect to pulsewidth τ, irradiation power density P monotone decreasing, irradiation energy density P * τ monotone increasing.
In fact, use peak pulse duration 40ns narrow, for example approximately the CVD laser of 7ns is tested, and is set in approximately 25mJ/cm by the irradiation energy density with each pulse
2(irradiation power density is set in approximately 3.5MW/cm
2), but the membranous cvd film of film forming metal.Relatively, irradiation power density is from 1MW/cm during with the experiment of itself and Fig. 2 and Fig. 3
2Rise to 3.5MW/cm
2, irradiation energy density is from 40mJ/cm
2Be down to 25mJ/cm
2This proof is by above-mentioned formula (3) and the pulsewidth τ of formula (4) expression and the relation of irradiation power density P and irradiation energy density P * τ.
Therefore, in the situation that pulsewidth is below the 40ns, be set in 1.0MW/cm by the irradiation power density with CVD laser
2It is above that (the irradiation energy density of each pulse is set in 40mJ/cm
2Below), in the situation that pulsewidth surpasses 40ns, be set in not enough 1.0MW/cm by the irradiation power density with CVD laser
2(the irradiation energy density of each pulse is set in super 40mJ/cm
2), but the membranous cvd film of film forming metal.
In addition, the irradiation energy density of CVD laser or irradiation power density need to be set to such an extent that comparison makes the cvd film of accumulation and the photomask of photomask bring the value of infringement low.
In addition, above value according to the CVD processing conditions (for example, the sizes of the size of the irradiation time of CVD laser, the concentration of unstrpped gas, point of irradiation, CVD processing etc.), the formation of the material of the substrate of photomask, photomask (for example, monofilm, two membranes, trilamellar membrane etc.), material and thickness etc. be different, in addition, also different according to its membrance casting condition.
In addition, as long as suitably set the condition of unstrpped gas in the mode of the membranous cvd film that obtains metal, then just need to not be at Q-switch set of frequency lower limit.But, reduce the Q-switch frequency, more can expect the raising of the correction quality (for example, transmissivity is irregular etc.) of halftone pattern, on the other hand, revise needed time growth.Therefore, consider the economy of photomask correction, such as the correction time with revise the product price, delivery date etc. of quality, photomask, preferably with the Q-switch frequency setting in suitable value.
For example, in the modification method of existing halftone pattern, need about 3 minutes irradiation times, this is equivalent in the present embodiment the Q-switch frequency setting in the situation that the about irradiation time of 1Hz.Therefore, if will be made as the correction time with more than the present par as condition, then the lower limit of Q-switch frequency is 1Hz.
In addition, according to the measurement result of Fig. 3, in order to be limited in below the permissible level transmissivity is irregular more reliably, preferably with the Q-switch frequency setting below 0.5kHz.
(halftone pattern correcting process)
Below, with reference to the flow process of Fig. 4, the photomask correcting process of being carried out by laser processing device 1 is described.In addition, below, the halftone pattern of enumerating to form at the shadow tone film 51 by the halftone pattern on the photomask 2 that is formed at Fig. 5 produces defective 52, and the situation of carrying out the correction of this halftone pattern is the example explanation.
In step S1,1 pair of defect pattern of laser processing device is carried out shaping.For example, 1 pair of shadow tone film of laser processing device, 51 irradiation ZAP laser are removed shadow tone film 51 by ZAP processing.
In addition, after the processing of step S1, the cvd film that causes for the residue that prevents ZAP processing and dispersing etc. evenly bad carries out the cleaning to photomask 2 sometimes.
In step S2, the scope of laser processing device 1 target setting transmissivity.Particularly, laser processing device 1 is with shape and the transmissivity identical with the halftone pattern of revising, as the reference pattern, use probe light and transmitted intensity analyzer 25 to measure the transmissivity with reference to pattern of actual exposure wavelength with the halftone pattern on the photomask 2 that does not generate defective.And the scope with reference to the regulation centered by the transmissivity of pattern that control part 26 will be measured is set as the scope of object penetrating rate.
In step S3, laser processing device 1 is set the CVD processing conditions.Particularly, with reference to Fig. 2 and Fig. 3, control part 26 is set as above-mentioned CVD processing conditions with the CVD processing conditions of laser processing device 1.That is, control part 26 uses the Q-switch frequency setting of laser oscillator 11 in the scope of 1Hz to 1.0kHz, more preferably in the scope of 1Hz to 0.5kHz CVD processing.In addition, control part 26 control gas cell 17 are the value that the concentration of chromium carbonyl gas is set as regulation with unstrpped gas.
In addition, control part 26 is controlled the optical attenuator of Ear Mucosa Treated by He Ne Laser Irradiation even intensity optical system 12, the average irradiation power density of CVD laser is set as the value of regulation.At this moment, under the pulsewidth of CVD laser is situation below the 40nm, take the irradiation power density of CVD laser as 1.0MW/cm
2Above, the irradiation energy density of each pulse is 40mJ/cm
2Following mode is set average irradiation power density, in the situation that pulsewidth surpasses 40nm, take the irradiation power density of CVD laser as not enough 1.0MW/cm
2, the irradiation energy density of each pulse is super 40mJ/cm
2Mode set average irradiation power density.
In addition, control part 26 is set sweep velocity or scanning times based on the sweep velocity of cut-and-dried object penetrating rate and point of irradiation or the table of comparisons of scanning times.At this moment, consider the deviation range of the transmissivity of cvd film, the mode that is not less than the scope of object penetrating rate with the transmissivity of the exposure wavelength of cvd film is set sweep velocity or scanning times.
At step S4, carry out CVD processing under the CVD processing conditions that laser processing device 1 is set in the processing of step S3.Thus, for example shown in Figure 7, at the upper film forming cvd film 61 of the vestige (being the retouch of halftone pattern) of removing half toning film 51.
In addition, before carrying out CVD processing, for the karyomorphism of the cvd film that easily carries out finished surface becomes, also can be with the irradiation power density that adds man-hour or the more power density processing department irradiation CVD laser to photomask 2.
In step S5, laser processing device 1 is measured the transmissivity of processing department.Namely same with the processing of step S2, measure the transmissivity of the cvd film 61 of new film forming.
In step S6, laser processing device 1 judges that transmissivity is whether in the scope of object penetrating rate.Namely, whether laser processing device 1 judge in the transmissivity of the cvd film 61 that the processing of step S5 is measured in the scope of the object penetrating rate that the processing of step S2 is set, and determining in the situation outside the scope of object penetrating rate, processes entering step S7.
In step S7, laser processing device 1 judges whether transmissivity is higher than the scope of object penetrating rate.Namely, laser processing device 1 judges whether the transmissivity of the cvd film 61 of measuring in the processing of step S5 is higher than the scope of processing the object penetrating rate of setting at step S2, under being judged to be than the high situation of the scope of object penetrating rate, processes entering step S8.
In step S8, laser processing device 1 is adjusted the CVD processing conditions.Particularly, laser processing device 1 changes to predefined value with Q-switch frequency, raw gas concentration, average irradiation power density.In addition, laser processing device 1 is set sweep velocity based on the table of comparisons of the sweep velocity of the difference of the measurement result of pre-prepd transmissivity and object penetrating rate and point of irradiation.
In addition, at this moment, for the inching of the transmissivity of the exposure wavelength that easily carries out cvd film, preferably set Q-switch frequency, raw gas concentration, average irradiation power density in the slow as far as possible mode of the film forming speed of cvd film.But, even with present halftone pattern correction the time, set under the identical CVD processing conditions, after the processing of step S9 in the thickness of the cvd film 61 that increases also thin, therefore, the possibility that cracks at cvd film 61 by ZAP processing is very low.
In step S9, laser processing device 1 carries out the CVD processing for the transmissivity inching.Be to carry out CVD processing under the CVD processing conditions set in the processing of step S7 of laser processing device 1, the thickness of the cvd film 61 by increasing some amounts carries out inching to the transmissivity of cvd film 61.
Afterwards, step S5 is returned in processing, until in step S6, determine transmissivity in the scope of object penetrating rate, or it is lower than the scope of object penetrating rate to determine transmissivity in step S7, the inching of the transmissivity of cvd film 61 is carried out in the repeatedly processing of execution in step S5 to S9.
On the other hand, in step S7, determine the transmissivity situation lower than the scope of object penetrating rate, even in the blocked up situation of the thickness of cvd film 61, process and return step S1, the processing that execution in step S1 is later.Namely remove newly-generated cvd film 61 by ZAP processing, again repeat finishing from the film forming of cvd film.
On the other hand, in step S6, determine in the situation of transmissivity in the scope of object penetrating rate, process entering step S10.
In step S10,1 pair of cvd film of laser processing device carries out shaping.For example shown in Figure 8, laser processing device 1 is processed cvd film 61A, the 61B that exposes from the pattern of stipulating in the cvd film 61 of removing film forming by ZAP, only keep cvd film 61C.In addition, at this moment, with reference to Fig. 2 and Fig. 3, therefore film forming cvd film 61 under above-mentioned CVD processing conditions, can not crack even cvd film 61 is carried out ZAP processing yet.
Afterwards, the photomask correcting process is finished.
As mentioned above, the transmissivity that can carry out with respect to the i line is the correction of the halftone pattern below 40%.The transmissivity that the exposure wavelength difference of the halftone pattern that in addition, can reduce to revise causes poor.
(2. variation)
In addition, after having represented in the above description to remove shadow tone film 51 fully, revise the example of halftone pattern, but also can be at the shadow tone film 51 rear correction halftone patterns of the periphery of only removing defective 52.
In addition, embodiments of the present invention are not limited to above-mentioned embodiment, can carry out various changes in the scope that does not break away from aim of the present invention.
Claims (3)
1. a photomask modification method carries out the correction of photomask, it is characterized in that,
Use the irradiation energy density of each pulse of penetrating from the laser oscillator of Q-switch frequency setting in the scope of 1Hz to 1kHz to be 40mJ/cm
2Above or irradiation power density is 1MW/cm
2Above Ultra-Violet Laser and the unstrpped gas that is made of the chromium carbonyl gas are at the retouch film forming cvd film of the halftone pattern of described photomask.
2. photomask modification method as claimed in claim 1 is characterized in that,
Use pulsewidth as below the 40ns and irradiation power density be 1MW/cm
2The irradiation energy density that above Ultra-Violet Laser or pulsewidth surpass 40ns and each pulse surpasses 40mJ/cm
2Ultra-Violet Laser.
3. a laser processing device carries out the correction of photomask, it is characterized in that possessing:
The Q-switch laser oscillation apparatus, it makes the Ultra-Violet Laser vibration;
Material gas supply device, it is to supplying with the unstrpped gas that is made of the chromium carbonyl gas near the retouch of the halftone pattern of described photomask;
Laser control apparatus, it controls irradiation energy density and the irradiation power density of each pulse of the Q-switch frequency of described Q-switch laser oscillation apparatus and Ultra-Violet Laser,
The Q-switch frequency setting of described Q-switch laser oscillation apparatus in the scope of 1Hz to 1kHz, is set in 40mJ/cm with the irradiation energy density of each pulse of Ultra-Violet Laser
2Above, or the irradiation power density of Ultra-Violet Laser is set in 1MW/cm
2Above, to described retouch irradiation Ultra-Violet Laser, generate cvd film at described retouch.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010172888A JP5163967B2 (en) | 2010-07-30 | 2010-07-30 | Photomask correction method and laser processing apparatus |
| JP2010-172888 | 2010-07-30 | ||
| PCT/JP2011/056242 WO2012014520A1 (en) | 2010-07-30 | 2011-03-16 | Photomask correcting method and laser processing device |
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| CN103026297A true CN103026297A (en) | 2013-04-03 |
| CN103026297B CN103026297B (en) | 2014-11-26 |
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| CN201180036907.8A Expired - Fee Related CN103026297B (en) | 2010-07-30 | 2011-03-16 | Photomask correcting method and laser processing device |
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| Country | Link |
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| JP (1) | JP5163967B2 (en) |
| KR (1) | KR101363905B1 (en) |
| CN (1) | CN103026297B (en) |
| TW (1) | TWI479258B (en) |
| WO (1) | WO2012014520A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104746041A (en) * | 2015-03-04 | 2015-07-01 | 深圳清溢光电股份有限公司 | Method for repairing white defect by way of laser vapor deposition |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103233217B (en) * | 2013-04-01 | 2015-11-18 | 北京工业大学 | The method of the micro-repairing of a kind of chromium mask transparency defect laser-transmitting |
| TWI710649B (en) * | 2017-09-12 | 2020-11-21 | 日商Ｈｏｙａ股份有限公司 | Photomask and method of manufacturing a display device |
| JP2018133591A (en) * | 2018-05-18 | 2018-08-23 | 大日本印刷株式会社 | Manufacturing method of template |
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| JP4979941B2 (en) * | 2005-03-30 | 2012-07-18 | Ｈｏｙａ株式会社 | Manufacturing method of glass substrate for mask blanks, manufacturing method of mask blanks |
| JP2009086382A (en) * | 2007-09-29 | 2009-04-23 | Hoya Corp | Gray tone mask blank and method for manufacturing the same, method for manufacturing gray tone mask and gray tone mask, and pattern transfer method |
| JP5126547B2 (en) * | 2009-03-10 | 2013-01-23 | オムロン株式会社 | Method and apparatus for forming CVD thin film |
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2010
- 2010-07-30 JP JP2010172888A patent/JP5163967B2/en active Active
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2011
- 2011-03-16 WO PCT/JP2011/056242 patent/WO2012014520A1/en active Application Filing
- 2011-03-16 CN CN201180036907.8A patent/CN103026297B/en not_active Expired - Fee Related
- 2011-03-16 KR KR1020137004996A patent/KR101363905B1/en active IP Right Grant
- 2011-07-28 TW TW100126706A patent/TWI479258B/en not_active IP Right Cessation
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| JPH04295851A (en) * | 1991-03-25 | 1992-10-20 | Nec Corp | Photomask correcting device |
| JPH086233A (en) * | 1994-06-20 | 1996-01-12 | Nec Corp | Method for correcting chipping defect of photomask and device therefor |
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| WO2002005032A1 (en) * | 2000-07-07 | 2002-01-17 | Hitachi, Ltd. | Method of manufacturing integrated circuit |
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| CN104746041A (en) * | 2015-03-04 | 2015-07-01 | 深圳清溢光电股份有限公司 | Method for repairing white defect by way of laser vapor deposition |
Also Published As
| Publication number | Publication date |
|---|---|
| TW201219965A (en) | 2012-05-16 |
| TWI479258B (en) | 2015-04-01 |
| CN103026297B (en) | 2014-11-26 |
| KR101363905B1 (en) | 2014-02-19 |
| WO2012014520A1 (en) | 2012-02-02 |
| KR20130042587A (en) | 2013-04-26 |
| JP2012032649A (en) | 2012-02-16 |
| JP5163967B2 (en) | 2013-03-13 |
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