JP2003031466A - Manufacturing method and apparatus of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove a film formed on the circumference of a wafer with excellent controllability, and to suppress generation of dust. SOLUTION: When a laser beam 32 is radiated to a film on the peripheral region of a semiconductor substrate 1, liquid 24 is supplied to an irradiated region, thus removing the film while suppressing generation of dust, suppressing the spread of the removed portion in the film to the inside of the semiconductor substrate, and hence improving the yield in semiconductor manufacturing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a semiconductor device using laser processing.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, a film is formed by coating an insulating film such as a photoresist film or an organic silicon oxide film, a film is formed by coating a polyimide film, or a metal thin film is formed by sputtering or plating. A film is formed by various methods such as a film.

It is known that in any of the film forming methods and film materials, the film forming control on the peripheral region of the semiconductor wafer greatly affects the yield in semiconductor manufacturing.

In the current semiconductor manufacturing process, a semiconductor wafer is installed in a wafer cassette when the semiconductor wafer is transferred between processes or when the wafer is transferred into a manufacturing apparatus. Therefore, if a film such as a photoresist film or a coating type insulating film is formed up to the circumferential end of the semiconductor wafer, the film at the circumferential end of the semiconductor wafer and the wafer cassette interfere with each other to generate dust. When such dust is generated, various defects such as exposure failure, wiring disconnection, and short circuit occur, and the yield is reduced.

Conventionally, in order to suppress the generation of these dusts, an etching chemical is selectively ejected from the nozzle to the edge of the semiconductor wafer, and the semiconductor wafer is rotated at a high speed, so that the photoresist film on the circumference and The coating type insulating film was removed.

However, in such a conventional wet etching method, it is difficult to control selectively removing only a fine area having a small area, and a large amount of the chemical solution is used, which adversely affects the environment. there were.

Further, when the metal thin film is formed up to the end of the semiconductor wafer by using the sputtering method or the plating method, the metal attached to the wafer cassette causes metal contamination, which reduces the yield. Therefore, when forming a metal thin film by the sputtering method, a ring-shaped metal mask is placed on the wafer in order to suppress the film formation at the wafer edge. Further, when the plating method is used, a device is installed to prevent the plating solution from entering the circumferential edge of the wafer.

Furthermore, in many cases, on the wafer circumference,
A serial number for distinguishing products is formed. When the metal thin film is formed on these serial numbers, it becomes difficult to read the serial numbers. Therefore, it is desired to establish a technique in which a metal thin film is not formed on the region where the serial number is formed.
However, it is difficult to selectively prevent the film formation on the region where the serial number is formed by the above-mentioned ring-shaped mask or the device that prevents the infiltration of the plating solution.

Conventionally, in order that the serial number can be read even when the metal thin film is formed, the step of the groove for forming the serial number is made deep. However, if the step is deepened, the dust is likely to be accumulated in the step, and the yield is reduced due to the influence of the dust.

In order to avoid such a problem, only the metal thin film on the region where the manufacturing number is formed is selectively selected so that the number can be read even when the number is formed with a shallow step. Need to be removed.

A laser processing technique is known as a method for selectively removing a thin film. However, when laser processing is performed in normal air, there is a problem in that dust is generated around the processing area and the yield is reduced.

[0012]

As described above, the photoresist, coating type insulating film, metal thin film, etc. in the peripheral region of the semiconductor wafer cannot be selectively removed with good controllability.

In view of the above circumstances, the present invention is capable of selectively removing the film on the peripheral region of the wafer with good controllability, suppressing the generation of dust, and contributing to the improvement of yield. It is an object of the present invention to provide a manufacturing method and a manufacturing apparatus of.

[0014]

A method of manufacturing a semiconductor device according to the present invention comprises a step of forming a film on a surface of a semiconductor substrate,
A step of irradiating a portion of the film formed in the peripheral region of the semiconductor substrate with a laser and removing the portion of the film, wherein the laser irradiation is performed in a state in which a liquid is supplied to the laser irradiation region. It is characterized by performing.

Here, it is desirable that the laser irradiation is performed while rotating the semiconductor substrate.

Pure water may be used as the liquid.

The film may be a photosensitive film and the liquid may be a developing solution.

Alternatively, the film may be a metal film containing copper and the liquid may be glycine hydrogen peroxide solution.

A transparent substrate may be installed at least on the laser irradiation region in a state of being separated from the semiconductor substrate, and the liquid may be supplied between the semiconductor substrate and the transparent substrate.

By irradiating the laser light while changing the beam diameter and / or the irradiation position of the laser light in the peripheral region of the semiconductor substrate, the width for removing the film can be changed.

A semiconductor device manufacturing method of the present invention is an apparatus for laser processing a semiconductor substrate, comprising a holding mechanism for holding the semiconductor substrate, a rotating mechanism for rotating the held semiconductor substrate, and the semiconductor substrate. And a liquid supply mechanism configured to supply a liquid to the laser irradiation region.

The liquid supply mechanism may further include a translucent substrate installed at least on the laser irradiation region in a state of being separated from the semiconductor substrate, and the liquid supply mechanism may be provided between the semiconductor substrate and the translucent substrate. It may be configured to supply the liquid.

[0023]

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

A schematic structure of a semiconductor device manufacturing apparatus according to an embodiment of the present invention is shown in a perspective view of FIG. 1, and a manufacturing method according to the present embodiment performed using this apparatus will be described.

In this apparatus, a holding mechanism (not shown) for holding the semiconductor wafer 1, the semiconductor wafer 1 is indicated by an arrow A.
Rotating mechanism for rotating in the direction of, a laser oscillator (not shown) for outputting the laser beam 31, a variable slit 15 as a beam shape converting mechanism for controlling the laser beam 31 into a desired beam shape, and the laser beam after passing through the variable slit 15. An irradiation optical system 17 for reducing and projecting the laser beam, and a mirror 18 for adjusting the irradiation position for irradiating the laser beam 32 on an arbitrary region on the semiconductor wafer 1.

Further, in the present apparatus, a liquid supply nozzle 21 as a liquid supply mechanism for supplying various liquids 24 such as pure water, thinner, and developing liquid in the direction of arrow B to the irradiation region of the semiconductor wafer 1 with the laser beam 32. A liquid recovery nozzle 22 for recovering the liquid 24 supplied onto the semiconductor wafer 1,
The laser light 3 is generated by flattening the surface of the liquid 24.
A transparent substrate 23 for preventing the scattering of 2 is provided.

The laser light is, for example, a Q switch YA.
G laser, which has a fundamental wave (wavelength 1064 nm), a second harmonic (wavelength 532 nm), a third harmonic (wavelength 355 nm),
Any of the wavelengths of the fourth harmonic (wavelength 266 nm) can be selected. Alternatively, for example, K with a wavelength of 248 nm
An rF excimer laser may be used.

Next, FIG. 2 shows a configuration relating to an electric control system and an optical system of this apparatus.

This apparatus comprises a control unit 11 and a laser oscillator 1.
4, beam shape conversion mechanism 15, half mirror 16, observation system 13, irradiation optical system 17, mirror 18, laser irradiation position control scope 12, XY-θ stage 10, liquid supply nozzle 21, liquid recovery nozzle 22, A transparent substrate 23 is provided.

The control unit 11 operates the laser oscillator 14 and the beam shape conversion mechanism 15 based on the output of the observation system 13 or the laser irradiation position control scope 12, and rotates the angle of the mirror 18 in the direction of arrow C. Let's control it.

The laser oscillator 14 has its on / off operation and light intensity controlled by the control unit 11, and outputs the above-mentioned Q-switch YAG laser light, KrF excimer laser light, or the like.

The beam shape conversion mechanism 15 converts the beam shape of the laser light output from the laser oscillator 14 into a desired shape, and specifically, the slit widths in the X-Y directions in the cross section of the laser light, respectively. It includes a variable slit that can be controlled independently.

The laser beam whose beam shape is converted by the beam shape conversion mechanism 15 is separated by a half mirror 16 into an irradiation optical system 17 and an observation system 13 and output.

The observation system 13 includes, for example, a photodetector, measures the light intensity of the laser light reflected by the half mirror 16, and outputs the result to the control unit 11. Alternatively, the observation system 13 includes a CCD camera, directly observes a portion irradiated with laser light, and outputs the observation result to the control unit 11. The control unit 11 controls the laser oscillator 14 so as to obtain a desired light intensity based on the given measurement result or observation result, and also operates the beam shape conversion mechanism 15 so as to obtain a desired beam shape. The mirror 18 is controlled so that the laser beam can be irradiated to a desired place.
Control the angle of.

The laser irradiation position control scope 12 includes, for example, a CCD camera, recognizes a predetermined portion such as a peripheral region of the semiconductor wafer 1 as image information, and outputs image data to the control unit 11. As a result, the control unit 11 controls the angle of the mirror 18 so that the laser light 32 irradiates a desired peripheral region of the semiconductor wafer 1 with good controllability.

The XY-θ stage 10 mounts the semiconductor wafer 1 and controls the movement in the XY direction and the rotation in the angle θ direction.

The liquid supply nozzle 21 is used for the semiconductor wafer 1
The liquid is supplied onto the region including the laser irradiation position in the peripheral region of and the liquid is caused to flow in the direction of arrow B.

The liquid recovery nozzle 22 recovers the supplied liquid.

The transparent substrate 23 is placed on the surface of the liquid 24 supplied from the liquid supply nozzle 21, and the laser beam 32 is scattered by the liquid 24 by flattening the surface of the liquid 24. Prevent.

A method of laser processing according to the present embodiment having the above configuration will be described. Laser oscillator 14
A laser beam is output from the laser beam and is converted into a desired shape by the beam shape conversion mechanism 15. A part of the converted laser light is given to the observation system 13 by the half mirror 16 and the other is given to the irradiation optical system 17.

When a part of the laser light is supplied to the observation system 13, the light intensity of the laser light output from the beam shape conversion mechanism 15 is measured, and the result is supplied to the control unit 11. Alternatively, the observation system 13 observes the laser irradiation spot on the semiconductor wafer 1 and outputs it to the control unit 11. The control unit 11 controls the angles of the laser oscillator 14, the beam shape conversion mechanism 15, and the mirror 18 so that a desired light intensity, beam shape, and laser irradiation position can be obtained.

The laser light applied to the irradiation optical system 17 is
After passing through the lens arranged in the irradiation optical system 17, the mirror 1
It is reflected by 8, passes through the transparent substrate 23 and the liquid 24, and is irradiated onto the film in the peripheral region of the semiconductor wafer 1. The liquid 24 is supplied from the liquid supply nozzle 21 onto the peripheral region of the semiconductor wafer 1, flows in the direction of arrow B, and is recovered by the liquid recovery nozzle 22.

As described above, by irradiating the film in the peripheral region of the semiconductor wafer 1 with the laser beam while the liquid 24 is supplied, it is possible to sufficiently remove the dust generated in the laser processing step. .

If the liquid supply nozzle 21 is constituted so as to include, for example, an ultrasonic vibrator having a piezoelectric element, the liquid 24 can be supplied while ultrasonic waves are being applied, and dust generated in the laser processing process. Can be effectively prevented from adhering to the peripheral portion of the liquid, and bubbles can be suppressed from being generated in the liquid used for laser light reflection, and the disturbance of the laser light due to such bubbles can be avoided and the processing efficiency can be improved. Further, such an ultrasonic transducer may be arranged on the back surface of the XY-θ stage 10.

Next, the result of laser processing according to the above embodiment will be described. In FIG. 3A, a photoresist film, a polyimide film,
Alternatively, the peripheral region 3 when the coating type insulating film 2 is formed
The longitudinal section of is shown. As the coating type insulating film 2, for example, an organic silicon oxide film containing a methyl group, SOG (SpinOn)
An insulating film such as a glass) film may be used.

Such a semiconductor wafer 1 is set on the XY-θ stage 10 in the apparatus shown in FIGS. 1 and 2 so that the laser beam 32 is irradiated onto the peripheral area of the semiconductor wafer 1. Then, the angle of the mirror 18 is adjusted to control the irradiation position.

Next, pure water 24 to which ultrasonic waves have been applied is supplied from the liquid supply nozzle 21, and while the semiconductor wafer 1 is being rotated, pulsed laser light is continuously oscillated and irradiated from the laser oscillator 14. Here, the laser energy per pulse is, for example, 0.1 J / cm ^{2 to} 0.5 J / cm ^2, and the energy is appropriately adjusted depending on the type of film. The wavelength of the laser light is, for example, 266 nm or 355 nm, and another wavelength may be selected according to the film thickness, the structure of the base, and the like. The processing position is controlled, for example, in units of about 10 μm.

FIG. 3 shows a state in which the film 2 on the peripheral region 3 of the semiconductor wafer 1 is removed by the irradiation of the laser beam 32.
It shows in (b). By removing the film 2 on the peripheral region 3 of the semiconductor wafer 1 in this way, when the semiconductor wafer 1 is transported using the wafer cassette, the film 2 does not interfere with the wafer cassette, and the generation of dust is suppressed. Therefore, the yield can be improved.

When the film on the peripheral region of the semiconductor wafer was removed by the conventionally used wet etching method, the removed region reached several mm, and the film thickness varied near the removed region. On the other hand, according to the present embodiment described above, it is possible to remove the film with a high processing accuracy of about 10 μm, and since the film thickness variation is suppressed, it is possible to more reliably suppress the generation of dust. it can.

In the above-mentioned embodiment, the film is removed by irradiating it with laser light while supplying pure water. But,
The laser processing may be performed using not only pure water but also other liquids depending on the material of the film.

In a manufacturing method according to another embodiment described next, a photosensitive film made of photoresist or photosensitive polyimide is formed on a semiconductor wafer, and the film on the peripheral region of the semiconductor wafer is removed by laser processing. At this time, a developing solution is supplied.

At this time, 1 in the laser beam continuously irradiated
The laser energy per pulse is, for example, 0.01 J /
cm ^{2 to} 0.1 J / cm ² . In the above embodiment,
Compared to the case where pure water is supplied and laser processing is performed, the removal can be performed with energy that is about one digit smaller.

The controllability of the removal region is about several μm, and it is possible to perform the processing with higher precision as compared with the case where the processing is performed using pure water in the above-mentioned embodiment.

A manufacturing method according to another embodiment of the present invention will be described. In this embodiment, a metal thin film containing Cu, Al, Ru, W, Ta, Ti or the like is formed on the surface of a semiconductor wafer. The semiconductor wafer 1 shown in FIG.
Consider a case where the manufacturing number 5 is formed in a part of the peripheral region of the. In this case, when the metal thin film 4 is formed on the surface of the semiconductor wafer 1, the manufacturing number 5 becomes almost unreadable as shown in FIG.

In this state, the metal thin film 4 on the peripheral region of the semiconductor wafer 1 is removed by using the above-mentioned manufacturing apparatus. The semiconductor wafer 1 is transferred to the XY-θ stage 10
While being installed on the semiconductor wafer 1 while rotating the semiconductor wafer 1, while appropriately changing the beam diameter of the laser light 32 by the beam shape conversion mechanism 15 and / or changing the irradiation position of the laser light 32 by the mirror 18, Irradiate with laser light. The beam diameter of the laser light 32 is small in a portion where the manufacturing number 5 is not formed in the peripheral region of the semiconductor wafer 1, is largely changed in a portion where the manufacturing number 5 is formed, and / or the manufacturing number 5 is formed. The laser beam 32 is irradiated only to the surface closer to the end portion in the non-formed portion, and the angle of the mirror 18 is controlled so as to include the region in which the manufacturing number 5 is formed in the portion in which the manufacturing number 5 is formed. Irradiate. The wavelength of the laser light at this time is, for example, 266 nm or 355 nm, and the energy per pulse is 1 J / cm ^{2 to} 3 J / cm ² , and pure water to which ultrasonic waves are applied is supplied from the liquid supply nozzle 21 during laser irradiation. To do.

When the metal thin film 4 is removed in this manner, the metal on the region 6 where the serial number 5 is not formed and on the region 7 where the serial number 5 is formed in the peripheral region of the semiconductor wafer 1 are removed. The shape of the removal of the thin film 4 is shown in FIG.
Shown in.

In the peripheral area of the semiconductor wafer 1, the film 4 is removed by a required width over the area 6 where the serial number 5 is not formed, so that interference with the cassette holder is prevented and dust generation is suppressed. . On the area 7 where the manufacturing number 5 is formed, the manufacturing number 5 can be read by removing the film 4 covering the area 7.

Here, pure water is used as the liquid to be supplied onto the region irradiated with the laser beam. However, when the metal thin film contains Cu as a main component, a chemical solution such as glycine hydrogen peroxide solution may be used. Glycine hydrogen peroxide solution has almost no effect on etching a metal thin film at room temperature. However, since the etching rate increases as the temperature rises, the metal thin film can be efficiently removed by the laser irradiation with a small energy by supplying the laser irradiation area. For example, laser energy per pulse by a ^{0.5J / cm 2 ~1.0J / cm 2} , it is possible to process a smaller energy than the case of performing processing by supplying pure water. In addition, the processing controllability when removing the metal thin film is also more accurate than when pure water is used.

By the way, the glycine hydrogen peroxide solution has a property of absorbing a laser beam having a wavelength of 266 nm or 355 nm. Therefore, when using this chemical solution, it is desirable to irradiate laser light having another wavelength, for example, 532 nm or 1064 nm.

The above-described embodiment is an example and does not limit the present invention. For example, a film or liquid material
You can freely select it according to your needs. The mechanism for irradiating the laser beam shown in FIGS. 1 and 2 is an example, and the mechanism is not limited to this. Furthermore, although it is the shape of a semiconductor substrate, it may be circular like a normal wafer,
Alternatively, one end may be straight, or other shapes can be applied to the present invention to remove the film in the peripheral region.

[0061]

As described above, according to the manufacturing method and the manufacturing apparatus of the semiconductor device of the present invention, when the film on the peripheral region of the semiconductor substrate is irradiated with the laser beam, the liquid is supplied to the irradiation region. By performing in the state, it is possible to remove the film while suppressing the generation of dust, it is also possible to prevent the removed portion of the film from spreading into the semiconductor substrate, it is possible to improve the yield of semiconductor manufacturing .

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a semiconductor substrate manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing in more detail the configurations of an electric control system and an optical system in the manufacturing apparatus.

FIG. 3 is a vertical cross-sectional view showing a state in which a peripheral portion of a film formed on the surface of a semiconductor substrate is removed by laser light irradiation.

FIG. 4 is a plan view showing that the serial number formed on the peripheral portion of the semiconductor substrate becomes unobservable due to the metal thin film formed on the substrate and is removed by irradiation with laser light so that it can be observed.

[Explanation of symbols]

1 Semiconductor wafer 2 membranes 3, 6 peripheral area 4 metal thin film 5 Serial number 7 Serial number forming area 10 XY-θ stage 11 Control unit 12 Laser irradiation position control scope 13 Observation system 14 Laser oscillator 15 Beam shape conversion mechanism 16 half mirror 17 Irradiation optical system 18 mirror 21 Liquid supply nozzle 22 Liquid recovery nozzle 23 Translucent substrate 24 liquid 31, 32 Laser light

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 21/304 643 H01L 21/304 647A 645 B23K 101: 40 647 H01L 21/30 577 // B23K 101: 40 21/302 ZF term (reference) 2H096 AA25 DA10 LA01 4E068 AH00 CG00 CH08 CJ07 DA10 5F004 AA16 BA19 BB03 BB04 BB18 BC08 DB03 DB08 DB23 5F046 JA22

Claims (9)

[Claims] 1. A step of forming a film on a surface of a semiconductor substrate, and a step of irradiating a portion of the film formed in a peripheral region of the semiconductor substrate with a laser to remove the film of the portion. The method of manufacturing a semiconductor device, wherein the laser irradiation is performed in a state where a liquid is supplied to a laser irradiation region. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the laser irradiation is performed while rotating the semiconductor substrate. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the liquid is pure water. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the film is a photosensitive film, and the liquid is a developing solution. 5. The method of manufacturing a semiconductor device according to claim 1, wherein the film is a metal film containing copper, and the liquid is glycine hydrogen peroxide solution. 6. A transparent substrate is installed at least on the laser irradiation region in a state of being separated from the semiconductor substrate, and the liquid is supplied between the semiconductor substrate and the transparent substrate. A method of manufacturing a semiconductor device according to claim 1. 7. A width for removing the film is changed by irradiating the laser light while changing a beam diameter and / or an irradiation position of the laser light in a peripheral region of the semiconductor substrate. Item 3. A method of manufacturing a semiconductor device according to item 2. 8. A semiconductor device manufacturing apparatus for performing laser processing on a semiconductor substrate, a holding mechanism for holding the semiconductor substrate, a rotating mechanism for rotating the held semiconductor substrate, and a laser in a peripheral region of the semiconductor substrate. An apparatus for manufacturing a semiconductor device, comprising: a laser irradiating unit for irradiating; and a liquid supply mechanism for supplying a liquid to an irradiation region of the laser. 9. The liquid supply mechanism further comprises a translucent substrate placed at least on the laser irradiation region in a state of being separated from the semiconductor substrate, wherein the liquid supply mechanism is provided between the semiconductor substrate and the translucent substrate. 9. The semiconductor device manufacturing apparatus according to claim 8, wherein a liquid is supplied.