JP2550370B2 - Semiconductor manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a semiconductor manufacturing apparatus using laser light.

(Conventional Technology) Conventionally, energy beam irradiation technology capable of locally supplying high-density power in a short time has been researched and developed as an alternative method for semiconductor manufacturing equipment using an electric furnace, etc. It is developing to the research of the element aiming at the original integrated circuit. This energy beam irradiation technology includes a method using a laser beam and a method using an electron beam. Especially, the laser beam is used for processing various semiconductors because it has little damage to the semiconductor wafer and thermal distortion. There is.

As processing using this laser beam, irradiation damage due to toon implantation, activation of implanted impurities, and recrystallization of polycrystalline silicon to produce single crystal silicon.
There is an annealing treatment device such as SOI (Silicon on Insnlator) technology, which is disclosed in Japanese Patent Publication No. 62-27532. Also,
Selective film formation on semiconductor substrate using laser beam
There is a CVD processing device, which is disclosed in JP-A-60-53017.

(Problems to be Solved by the Invention) In the above Japanese Patent Publication No. 62-27532, switching on and off of laser light for processing a desired place is performed by lowering laser output or shielding laser light. However, when the output of the laser oscillator is reduced, it takes time to return to a stable high output state again. Therefore, in a laser annealing apparatus, the laser light is usually shielded by an acousto-optic modulator. However, when a high-power Ar laser is modulated by an acousto-optic light modulator, if non-diffracted light (0th order light) is used as an annealing beam, the non-diffracted light cannot be completely extinguished, so that it is unnecessary. However, if the first-order diffracted light is used as an annealing beam,
There is a problem that the diffraction angle changes depending on the output wavelength and the beam is dispersed. In addition, there is a problem that the acousto-optic light modulator for high-power laser is very expensive.

Further, in the mechanical shutter disclosed in Japanese Patent Laid-Open No. 60-53017, since the laser light is shielded by the shutter and the laser light is absorbed by the shutter, the heat of the shutter becomes high and the shutter itself is destroyed by the heat or the surrounding area. There is a problem that the optical lens and the high-precision stage are thermally affected.

The present invention has been made to solve the above-mentioned problems, and reliably blocks laser light without dispersing it to the surroundings, and there is no risk of damage to the surroundings due to thermal influences. An object of the present invention is to provide a semiconductor manufacturing apparatus capable of stably processing a substrate.

[Structure of Invention]

(Means for Solving the Problems) A semiconductor manufacturing apparatus of the present invention is a semiconductor manufacturing apparatus for performing processing by irradiating a surface to be processed of a substrate to be processed with a laser beam, wherein an optical path of the laser beam is a mirror rotation type shutter. A blocking unit for blocking the light; and a cooling unit having a concave inner wall surface for directly absorbing and cooling the laser light blocked by the blocking unit and having a hole through which the laser light can pass. It is characterized by having done.

(Operation) According to the present invention, when the surface to be processed of the substrate to be processed is irradiated with the laser light and a predetermined processing is performed, the laser light is cut from 0% by the mirror rotation type shutter of the optical path blocking unit. It can be reliably switched to 100%, and the laser light that is blocked and reflected by the mirror rotation shutter is directly incident on and absorbed by the concave inner wall surface of the cooling unit, preventing dispersion to the surroundings. It is possible to prevent the thermal influence of the laser light on the precise optical lens, etc., and the unshielded laser light passes through the light of the cooling part and is sent to the substrate to be processed and can be subjected to a predetermined processing. .

(Embodiment) An embodiment in which the device of the present invention is applied to a laser annealing device for synthesizing and annealing two laser beams in a semiconductor manufacturing process will be described below with reference to the drawings.

An airtight chamber (1) made of Al that can be opened and closed by an opening / closing mechanism (not shown) is provided, and a semiconductor wafer (2) is held in the chamber (1) by pressing an edge of a substrate to be processed, for example, a semiconductor wafer (2). The semiconductor wafer (2) and the installation table (3) that holds the wafer so that the surface to be processed is facing down.
Multiple IRs with reflector (4) preheated to about 0 ° C
A lamp (infrared ray lamp) (5) is provided.

Further, below the semiconductor wafer (2) in the chamber (1), a window (6) made of a material that transmits laser light, for example, quartz glass is provided.

Two laser oscillators (7a, 7b), for example, 18 WAr ion lasers are provided so as to output a large output laser beam. A blocking unit (8a, 8b) capable of blocking the laser beam with a mirror, for example, a galvano scanner as a mirror rotation shutter is provided on each optical path of the output laser beam, and is reflected by the mirror of the blocking unit. A cooling unit (9a, 9b) that absorbs laser light and cools with water cooling, forced air cooling or natural air cooling, for example, a black alumite treated Al heat sink is provided. Then, the laser beam that has passed through without being blocked by the blocking unit is temporarily beamed by a beam expander (10a, 10b) so that the beam diameter during processing can be narrowed to a beam diameter suitable for annealing processing, for example, to the minimum. A beam expander (10a, 10b) is installed on the optical path so that the diameter is expanded to about 3 times.

Then, a total reflection mirror (11a) and a polarizing prism (1) are used to combine the two laser beams into a desired positional relationship.
2) For example, a prism whose material is BK7A is provided.

Further, in order to adjust the beam profile and the like of the combined laser light, for example, two reflection type optical attenuators (13a, 13b) capable of switching between 100% reflection and 1% reflection are set. Further, total reflection type mirrors (11b to 11f) are installed so that laser light can be transmitted to the lower part of the chamber (1).

A scanning unit (14) is provided so that the laser beam sent to the lower portion of the chamber (1) can be scanned on the semiconductor wafer (2) through the window (6). In the scanning section (14), an X-direction scanning mechanism (15), for example, a galvano-scanner which is a mirror rotation type scanning mechanism, is used in a Y-direction scanning mechanism (16), for example, a single axis using a ball screw capable of highly precise and minute feed. It is provided on the precision stage. Then, the laser beam scanned by the X-direction scanning mechanism (15) is scanned at a constant speed f
The θ lens (17) is also provided on the Y-direction scanning mechanism (16).

The operation of the laser annealing apparatus having the above configuration is controlled and set by a control unit (not shown).

Next, a method of annealing the semiconductor wafer (2) by the above-described laser annealing device will be described.

The chamber (1) is opened by an opening / closing mechanism (not shown),
The semiconductor wafer (2) is carried into the chamber (1) by a hand arm (not shown). Here, semiconductor wafer (2)
For example, center alignment and orientation flat alignment are performed in advance by detecting the edge of the wafer (2) at three or more points with a photodiode or the like and performing calculation. Then, the wafer (2) is loaded into the chamber (1) with the surface to be processed facing downward, and the wafer (2) is placed on the installation table (3) in the chamber (1).
Hold the edge of about 5 mm and hold it downward on the installation table (3). At this time, if the semiconductor wafer (2) is preheated, damage to the wafer (2) due to thermal expansion can be prevented.
Then, the chamber (1) is closed by an opening / closing mechanism (not shown).

Then, the semiconductor wafer (2) is heated by the reflection plate (4) and the IR lamp (5) to about 500 ° C., and then annealed by laser light. The uniform heating by the IR lamp (5) can prevent thermal strain and the like generated by local heat generation of the laser light. In addition, when the chamber (1) is purged with N ₂ gas during the annealing treatment, the temperature uniformity is further improved.

At this time, the two laser oscillators (7a, 7b) have already been stabilized in a high output state, and the laser light is reflected by the reflecting mirror (20) of the cutoff section (8) as shown in FIG. The heat is absorbed by the cooling part (9) having the hole (21) through which the heat can pass, for example, the concave inner wall surface of the heat sink, and the heat of the laser hole is cooled by natural cooling. When the laser light is annealed, the reflecting mirror (20) is rotated so as to be parallel to the laser light, and the laser light is emitted from the hole (21). This rotation mechanism is a galvano scanner which is a mirror rotation type shutter, and since it is a high speed shutter of about 10 msec for rotating an angle of about 20 °, it adversely affects the annealing process on the semiconductor wafer (2). There is no. Further, as shown in FIG. 3, if an emergency cutoff mirror (22) is provided so that the laser light is cut off when the power is cut off, the accident due to the laser light is prevented even in the case of a power failure. be able to. By providing the cutoff section (8) and the cooling section (9), the output of the laser oscillator (7a, 7b) is kept at a high output and the conversion of 0% and 100% of the laser output is ensured at high speed. It is possible to prevent the adverse effects of heat on the surroundings, and it is possible to turn on and off the high-power laser at low cost.

Then, the laser light that has passed through the blocking section (8a, 8b) for annealing treatment is converted into a beam expander (10a, 10b).
The beam diameter is once expanded to about 3 times. This is performed in order to narrow down the beam on the semiconductor wafer (2) to obtain an appropriate beam diameter for the annealing process, which enables the wafer (2) to be annealed at a higher temperature, for example, 1000 ° C or higher. Becomes

Next, the two laser beams are reflected by a mirror (11a) and a polarizing prism (1
Create a desired beam profile by combining in 2),
The laser light is sent to the scanning section (14) using mirrors (11b to 11f). At this time, when the beam profile or the like is adjusted, the laser light output is attenuated by using the optical attenuators (13a, 13b). The mechanism of the optical attenuator (13a, 13b) is, as shown in FIG. 4, a plurality of mirrors having different reflectances, for example, a 100% reflecting mirror (30) that reflects 100% of laser light and 99% by reflecting 1%. A 1% reflecting mirror (31) that transmits and absorbs, for example, a linear guide (3
2) and the parallel movement mechanism that uses the air cylinder (33) to change the parallel movement to achieve 100% laser output.
And decays to 1%. Further, this switching may be performed by rotational movement. In this embodiment, the laser output attenuation of 100%, 1% and 0.01% is possible by using the two optical attenuators (13a, 13b). As a result, the desired attenuation rate required for each adjustment is realized. Further, since the 1% reflecting mirror (31) transmits and absorbs 99% of the laser light, a heat sink (not shown) for cooling is provided on the back surface to prevent thermal influence on the periphery. And this 100% reflector (30)
Type optical attenuator (13a, 13
By using b), it is possible to prevent laser light interference, optical path bending, laser light diffusion, wavefront disturbance, and the like that occur in a transmission type optical attenuation mechanism or the like. Further, in the case of performing light attenuation in two or more steps as in the present embodiment, in the transmission type light attenuation, it is necessary to make a parallel plane plate which is precise and parallel and is capable of transmitting laser light. Although the adjustment is difficult or the optical path correction plate is required to correct the optical path, for example, the reflection type solves the above problems, and a highly accurate optical attenuation mechanism can be easily realized.

Then, the adjusted laser light such as the beam profile and the optical axis is sent to the scanning unit (14) using the mirrors (11b to 11f). Here, the laser light has a desired constant speed by the X-direction scanning mechanism (15), for example, a carbano scanner and an fθ lens (17), and passes through the window (6) to move the X-ray on the semiconductor wafer (2).
Similarly, the Y-direction scanning mechanism (16), for example, 1
The axial precision stage scans the semiconductor wafer (2) in the Y direction by desired scanning such as continuous scanning or slap scanning.
The laser beam focused by the fθ lens (17) has a beam diameter of about 60 μm to 300 μm on the semiconductor wafer (2), and the temperature of the surface to be processed of the semiconductor wafer (2) becomes 1000 ° C. or higher, for example. This heat causes the wafer (2) to be annealed, and the X direction scanning mechanism (15) and the Y direction scanning mechanism (16) scan the desired portion or the entire surface of the wafer (2) to perform the annealing process. finish.

Next, after blocking the laser light by the blocking sections (8a, 8b), the chamber (1) is opened by an opening / closing mechanism (not shown), and the semiconductor wafer (2) is carried out of the chamber (1) by a hand arm (not shown). , Processing is completed.

The blocking unit (8a, 8b) in the above embodiment has been described by using a carbano scanner as a mirror rotary shutter, but it is sufficient if the optical path can be blocked by a mirror, and a rotary cylinder or a rotary solenoid may be equipped with a mirror. Alternatively, the mirror may be moved linearly at high speed to block the optical path.

Further, the cooling unit (9a, 9b) of the above-described embodiment is described using the air-cooling black heat-treated alumite heat sink made of Al, but if it can cool by absorbing the laser light reflected from the blocking unit (8a, 8b). Any method may be used, such as a water cooling method using cooling water or forced air cooling using a fan, and is not limited to the above embodiment.

In the above embodiment, the beam expander (10a,
The beam diameter was once expanded in 10b) and narrowed down with the fθ lens (17), but it is sufficient if the desired beam diameter and beam output can be obtained on the semiconductor wafer (2), and the laser oscillator (7a, 7b)
It is also possible to use the laser light emitted from the laser as it is and narrow it down onto the wafer (2) using a lens.

Further, in the above-mentioned embodiment, the description has been made by setting the parallel movement switching type optical attenuators (13a, 13b) of 100% reflection and 1% reflection in two places, but the reflectance, the switching method and the set number are the same as in the above embodiment. It goes without saying that it is not limited.

Then, in the scanning unit (14) of the above-described embodiment, the X-direction scanning mechanism (15) and the Y-direction scanning mechanism (16) are described using the galvano scanner and the one-axis precision stage, but desired processing can be realized. Any scanning method may be used, either a raster scan method or a vector scan method, an XY stage may be used, a polygon mirror and a uniaxial stage may be used in combination, and two galvano scanners may be used. It may be used and is not limited to the above embodiment.

In the above-described embodiment, the laser annealing apparatus that combines the two laser beams and performs the annealing process has been described, but any semiconductor manufacturing apparatus that processes the substrate to be processed using the laser beam may be used. Needless to say, the laser light used may be one or a plurality of laser lights, and the treatment may be a CVD treatment or a mask repair treatment, and is not limited to the above embodiment.

As described above, according to this embodiment, the semiconductor wafer (2) is preheated by the IR lamp (5) in the airtight chamber (1) and annealed by using laser light through the window (6). Then, on the optical path of the laser beam, a blocking unit (8a, 8b) for blocking the laser beam with a mirror and a cooling unit (9a, 9b) for cooling the blocked laser beam are provided to output the laser beam. By instantaneously switching from 0% to 100% and processing the wafer (2) with laser light, the laser light can be reliably cut off, and the influence of heat on the vicinity of the cutoff part can be prevented. It is also possible to prevent the diffusion of laser light and the like.

〔The invention's effect〕

As described above, according to the present invention, in the semiconductor manufacturing apparatus that performs processing by irradiating the surface to be processed of the substrate to be processed with laser light, a blocking unit that blocks the optical path of the laser light with a mirror rotary shutter, By providing a cooling inner portion having a concave inner wall surface for directly absorbing and cooling the laser light blocked by the shielding portion and having a hole through which the laser light can pass, the laser light It is possible to provide a semiconductor manufacturing apparatus capable of reliably blocking a substrate without being dispersed to the surroundings, without damaging the surroundings due to a thermal effect, and stably performing processing of a substrate to be processed by laser light. it can.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment in which a semiconductor manufacturing apparatus of the present invention is applied to an annealing treatment, FIG. 2 is a cross-sectional view for explaining a cutoff portion and a cooling portion of FIG. 1, and FIG. 3 is FIG. FIG. 4 is a longitudinal sectional view of FIG. 4, FIG. 4 is a view for explaining the optical attenuator of FIG. 1, and FIG. 5 is a flow chart briefly showing the annealing treatment of FIG. In the figure, 1 ... Chamber, 2 ... Semiconductor wafer 5 ... IR lamp, 6 ... Window 8, 8a, 8b ... Blocking section, 9, 9a, 9b ... Cooling section 13a, 13b ... Optical attenuator, 14 ... Scanning section 17 ... fθ lens, 20 ... Reflector 21 ... Hole, 30 ... 100% reflector 31 ... 1% reflector

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shimao Yoneyama 1-26-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Tokyo Electron Limited (56) Reference JP-A-61-17392 (JP, A) JP-A-53-14495 (JP, A)

Claims (2)

(57) [Claims] 1. A semiconductor manufacturing apparatus for irradiating a surface to be processed of a substrate to be processed with a laser beam, and a blocking section for blocking an optical path of the laser beam with a mirror-rotating shutter, and a blocking section for blocking the beam path. And a cooling unit having a concave inner wall surface for directly absorbing and cooling the laser light, and a cooling unit having a hole through which the laser light can pass, on the inner wall surface. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the mirror rotary shutter is a galvano scanner.