JP3525841B2 - Laser repair method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to laser repair of masks for semiconductor devices and display devices, and more particularly to CVs.
The present invention relates to a D processing method, a removal processing method, and an apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, a laser repair apparatus for correcting a defect such as a semiconductor photomask has a laser unit equipped with a laser light source, a laser irradiation observation unit equipped with an optical system for guiding a laser beam onto a substrate and an observation apparatus, a CVD gas, Gas supply / exhaust unit for Zap gas, XY for holding substrate
A stage and a control unit for controlling them are provided. Further, a window port that is provided with a gas supply / exhaust nozzle and holds the gas and introduces a laser beam is arranged close to the substrate surface.

In particular, since the structure of the window port influences the gas flow on the substrate, which greatly affects the formation and removal of the film, various structures have been proposed.

In Japanese Patent Laid-Open No. 10-324973, a raw material gas blowing nozzle of a gas introducing portion (corresponding to the window port) is formed obliquely with respect to a substrate surface and has a blowing opening portion on the lower surface of the gas introducing portion. . Further, the gas introduction part is provided with a reverse nozzle formed near the tip of the nozzle to blow out gas in the opposite direction, so that the mixing of air from around the gas introduction part to the laser beam irradiation part is suppressed. In addition, a purge gas for preventing window dirt is introduced so as to strike the laser beam irradiation window in parallel with each other in a symmetrical manner.
For this reason, since the flow of the purge gas has good symmetry with respect to the optical axis, it is possible to suppress the mixing of air from around the gas introducing portion.

Further, in Japanese Patent No. 2776218, a hole for a nozzle is formed in a thin transparent glass, and this is used as a nozzle for supplying a CVD gas to a laser beam irradiation portion on a substrate.
It discloses a configuration in which a CVD gas is sprayed onto an irradiation point along the optical axis.

[0006]

In a photomask repairing apparatus for a large area display, a repairing apparatus capable of repairing a large defect of 20 μm or more at high speed is desired. When forming (correcting) a large area in a lump, it becomes difficult to secure the uniformity of the film. Further, there arises a problem that the state of film formation becomes unstable depending on the supply direction of the CVD gas.

[0007]

It is an object of the present invention to provide a laser repairing method and apparatus which can stably form a film of a large defect portion.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a laser for supplying a CVD source gas to a substrate surface and irradiating a predetermined portion on the substrate surface with a laser beam to correct a defect on the substrate. The laser repair method is a repair method in which a purge gas is introduced into the substrate surface from directly above the substrate surface and a CVD source gas is introduced in parallel to the substrate surface. The purge gas is preferably introduced directly above the substrate surface from two nozzles arranged opposite to each other.

[0010]

The laser repair apparatus of the present invention comprises a laser beam irradiation section, a gas supply / exhaust section, a substrate setting XY stage, a control section for controlling them, a laser beam irradiation window and a gas introduction space section. A port portion provided with a gas supply port and a gas exhaust port in the vicinity of the substrate surface, the port portion being provided with two purge gas inlets facing each other, and disposed below the purge gas inlet. A CVD raw material gas introduction port and a vaporization gas introduction port, and the CVD raw material gas introduction port is formed so that the CVD raw material gas is discharged parallel to the substrate surface. Further, the gas introducing space portion may include a tapered space portion whose diameter increases toward the upper surface of the port and a cylindrical space portion below the tapered space portion. It is desirable that the CVD raw material gas introduction port is installed at a position where the CVD raw material gas is discharged into the cylindrical space portion of the gas introduction space portion. A ring-shaped gas exhaust port may be formed on the lower surface of the port portion around the opening of the gas introduction space.

With the apparatus and method as described above, it is possible to stably form a film of a large defect portion.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings.

FIG. 3 shows an example of the overall construction of the laser repair apparatus of the present invention. The window port 1 is arranged on the XY stage 14 on which the substrate 7 such as a defective Cr photomask is placed with a slight distance from the substrate.
The window port 1 has an inlet for supplying a laser CVD gas, a purge gas for preventing window contamination, and a vaporizing zap gas to the laser irradiation portion on the substrate, and prevents the CVD gas from leaking to the outside of the window port 1. In addition, it is provided with a suction port for sucking evenly into the surroundings (for details, see FIGS. 2 and 3). A laser irradiation observation unit 10 is installed immediately above the window port 1. The laser irradiation observation unit 10 includes an attenuator that changes the irradiation power of laser light, a variable aperture mechanism that changes the shape of laser light that is irradiated, a mechanism that adjusts the focus position by moving the objective lens up and down, and a pattern of the laser light irradiation unit. It has a known configuration (not shown) including a microscope mechanism for observing the shape. Laser light emitted from a laser unit 12 having laser light sources for laser vaporization and laser CVD is emitted from a laser irradiation observation unit 10 and a window port 1.
A predetermined portion on the substrate 7 is irradiated with the light through.

The laser repair device further includes a gas supply / exhaust unit 11 and a control unit 8. The gas supply / exhaust unit 11 includes a mechanism for supplying the CVD gas, the purge gas, and the evaporation zapping gas to the window port 1 at necessary timings, and detoxifying the exhaust gas sucked from the window port 1. . The control unit 8 controls the emission timing of the laser light, the operation of the XY stage 14, the timing control of the gas opening / closing valve of the gas supply / exhaust unit 11, the illumination of the laser irradiation observation unit 10, the aperture control, the attenuation rate control of the attenuator. Control the operation of each unit in the laser repair device.

In the above laser repair device, the light source is N
d: Using the third harmonic of a YLF laser (wavelength 349 nm, pulse repetition 4 kHz, pulse width 30 ns), laser CVD method using Cr (CO) 6 as a source gas, for example, pattern defect defect of photomask for semiconductor is corrected. can do. On the other hand, the residual defect in which the extra pattern remains is the third harmonic (wavelength 351) of the Nd: YLF laser.
nm, repetitive 30 Hz, pulse width 20 ps) can be removed by a laser evaporation method to correct the pattern.

A configuration example of the window port 1 will be described with reference to FIGS. FIG. 1 is a sectional view of the window port 1. The disk-shaped window port 1 is
A gas introduction space is formed in the center. The space is
The diameter is constant from the lower surface of the window port 1 to a predetermined height, but the diameter is tapered from the middle toward the upper surface. A window 4 for introducing laser light is formed on the upper surface of the window port 1 so as to cover the upper opening of the gas introducing space.

Immediately below the window 4 of the window port 1, two purge gas inlets 3 for introducing a purge gas for preventing fogging of the window 4 into the gas inlet space are provided in parallel with each other in parallel to the substrate surface. The purge gas is blown out from the side surface of the gas introduction space portion directly below the window 4, two flows collide with each other directly below the window 4, and descend downward of the gas introduction space portion substantially vertically to the surface of the substrate 7. On the other hand, the CVD gas inlet 2 is
The gas introduction space is provided so that the CVD gas is introduced horizontally to the surface of the substrate 7 in a region having a constant diameter. The CVD gas is blown out from the nozzle 2, mixes with the flow of the purge gas, and descends almost vertically to the upper surface of the substrate 7, and diffuses into the CVD space between the window port 1 and the substrate 7. An exhaust port 6 for sucking gas is formed on the lower surface of the window port 1.

The zap gas introduction port 5 is a region having a constant diameter in the gas introduction space and is formed with a predetermined inclination with respect to the surface of the substrate 7, and supplies zap gas from a diagonally upper position to a predetermined position on the substrate surface. To do.

FIG. 2 is a plan view of the lower surface of the window port 1. A gas introduction space is formed in the center, and a CVD gas introduction port 2 and a zap gas introduction port 5 are formed in a portion where the diameter of the space is constant. The CVD gas exhaust port 6 is formed in a ring shape so as to surround the lower end opening of the gas introduction space. With this structure, the gas is sucked into the surroundings evenly. The gas sucked into the exhaust port 6 is sent from the four suction suction ports 13 to the gas supply / exhaust unit 11. The circular broken line portion in the center of FIG. 3 indicates the upper end opening of the gas introduction space portion.

In the window port 1, the diameter of each nozzle is about 0.3 mm, and the upper end diameter of the gas introduction space is 10 mm.
˜20 mm, the lower end diameter is about 3 mm, and the ring-shaped CVD gas suction port 6 has a diameter of about 10 mm. The window port 1 is arranged at a distance of about 0.3 mm from the substrate 7.

Next, the laser repair method of the present invention will be described. First, the repair of defective defects will be specifically described. First, in the standby state before setting the substrate 7,
A purge gas composed of Ar gas is flown at a flow rate of 500 sccm, and exhaust is performed from the exhaust port 6 at an exhaust flow rate of 2 L / min.
Next, after setting the substrate 7 on the XY stage 14,
CVD of mixed gas of Cr (CO) 6 diluted with Ar gas
C as a gas at a flow rate of 50 sccm and a pressure of 1 Torr
The gas is introduced from the VD gas introduction port 2 into the gas introduction space. CV
When the D gas inlet 2 is horizontal to the substrate surface, the gas concentration of the laser irradiation portion of the substrate 7 is 0.
This corresponds to 3 Torr, and a sufficient gas concentration for performing good CVD can be supplied. Moreover, since the distance between the surface of the substrate 7 and the lower surface of the window port 1 is properly adjusted, C
The flow of VD gas is grazing over the surface of the substrate,
The gas flow velocity of the laser irradiation part on the substrate is reduced.

Next, the processing size and position are set in accordance with the position of the defective defect, the attenuator is set so that a predetermined processing power is obtained, and a predetermined region on the substrate 7 is irradiated with laser light for 3 seconds to perform laser CVD. I do. As a result, even if the size of the pattern to be CVD is as large as 25 μm □, the uniformity of the film is ensured in the formed region, and a film having a sufficient light shielding property necessary for a photomask is stably formed. You can

On the other hand, in the structure in which the direction of the CVD gas inlet is directed to the laser irradiation portion on the substrate, the flow of the purge gas disturbs the flow of the CVD gas, so that the CVD gas having a sufficient concentration cannot be supplied to the laser light irradiation portion. . Further, in the case of the CVD gas inlet having this configuration, when the direction in which the CVD gas is blown out (upstream side) is compared with the direction in which the CVD gas is blown out (downstream side), the film formation on the upstream side is difficult to extend and conversely the film formation on the downstream side. The film growth rate varies greatly depending on the film formation direction. For this reason, a relatively large 10 μm
□ In the case of the above film formation, the way of attaching the film changes depending on the film formation direction, and the light shielding property becomes partially defective when the film is formed upstream.

Next, the procedure for correcting the residual defects will be described. A zap gas consisting of air is supplied onto the substrate 7 from the zap gas introduction port 5. In this state, the position and size of the residual defect to be repaired are adjusted by operating the laser irradiation observation unit 10 and the XY stage 14 via the control unit 8. Next, the attenuator is set so that the laser processing power has a predetermined value, and a laser pulse is irradiated for 2 seconds under the condition of 60 shots to remove residual defects.

The processing size is 5 μm □, and the laser power is changed as follows when the gas flow rate is changed under the condition that the verticality of the edge during evaporation processing is good.

(1) In the state where the purge gas and the zap gas are not flowed, fine particles of about 0.1 μm are deposited in a circular area of about 20 μm around the processed portion on the substrate so that the density becomes high at the irradiation center. , 0.3 μm fine particles are concentrated and deposited on a place on the donut with a radius of 10 μm centered on the laser irradiation portion.

(2) When the purge gas is 500 sccm and the zap gas is in the range of 50 sccm to 200 sccm, fine particles of about 0.3 μm are not deposited,
Fine particles of about 0.1 μm are deposited as in (1).

(3) The flow rate of zap gas is 250 scc
In the range from m to 1500 sccm, observable 0.
Fine particles of 05 μm or more are not seen, which is improved to a practically negligible level.

When the flow rate from the nozzle is converted into the flow rate at the laser irradiation part on the substrate, the flow rate of the zap gas is 250.
sccm corresponds to 15 m / s. Therefore, it can be seen that when removing the residual defects, if the flow rate of the zap gas at the laser irradiation portion is set to 15 m / s or more, the accumulation of fine particles can be removed. As for the type of gas for ZAP, the flow rate is 15m even if nitrogen gas or argon gas is used in addition to air.
If it is / s or more, a remarkable effect of removing fine particles is observed.

The gas introduction space at the port portion may have a cylindrical shape as a whole. Further, two CVD gas inlets may be arranged so as to face each other.

[0032]

According to the laser repair method and apparatus of the present invention, in repairing defect defects caused by film formation, film formation of 25 μm or more can be carried out collectively and with high quality.

[Brief description of drawings]

FIG. 1 is a sectional view of a window port.

FIG. 2 is a plan view of the lower surface of the window port.

FIG. 3 is a diagram showing a configuration example of a laser repair device of the present invention.

[Explanation of symbols]

1 window port 2 CVD gas inlet 3 Purge gas inlet 4 windows 5 Zap gas inlet 6 exhaust port 7 substrate 10 Laser irradiation observation unit 14 XY stage

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C23C 16/455 C23C 16/48 G02B 5/20 G02B 6/02 G02F 1/13 G03F 1/08 B23K 26/00

Claims (6)

(57) [Claims] 1. A laser repair method for supplying a CVD source gas to a substrate surface and irradiating a predetermined portion on the substrate surface with laser light to repair defects on the substrate, wherein a purge gas is used for the substrate surface.
Introduce from directly above to the substrate surface and flatten the CVD source gas on the substrate surface.
A laser repair method, characterized by being introduced into a row . 2. The purge gases are arranged so as to face each other.
The nozzles are introduced from two nozzles directly above the substrate surface.
Laser repair method. 3. A laser beam irradiation section, a gas supply / exhaust section,
Substrate installation XY stage and control unit for controlling them
Laser light irradiation window, gas introduction space and gas supply port.
And a port part that is installed close to the board surface with an exhaust port
A laser repair device comprising:
Two purge gas inlets arranged to face each other,
CVD source gas arranged below the purge gas inlet
The CVD raw material, which is provided with an inlet and an evaporation gas inlet.
At the gas inlet, the CVD source gas is discharged in parallel with the substrate surface.
Laser repair characterized by being formed like
apparatus. 4. The gas introducing space portion faces the upper surface of the port.
Taper space part with larger diameter and cylindrical shape below
The laser repair device according to claim 3, further comprising a space portion. 5. The CVD source gas inlet is empty for gas introduction.
At the position where the CVD source gas is released to the cylindrical space between
The laser repair device according to claim 4, which is installed. 6. A gas introducing space portion is opened on the lower surface of the port portion.
4. A ring-shaped gas exhaust port is formed around the mouth.
The laser repair device described.