JP3451477B2 - Laser annealing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a laser annealing apparatus.

[0002]

2. Description of the Related Art In the field of semiconductor manufacturing, after implanting ions into a semiconductor substrate, the purpose is to remove the crystal strain (lattice defect) caused by the ion implantation or to activate the implanted ions. Heat treatment (annealing) of the semiconductor substrate is performed. As one of the devices for performing such annealing, there is a laser annealing device for performing annealing using a laser beam.

Laser annealing equipment is also used to melt and recrystallize amorphous silicon thin films for the purpose of making polycrystalline silicon thin films.

A conventional laser annealing apparatus is a laser oscillator (excimer laser, etc.) for generating a laser beam.
An optical system for shaping the laser beam from the laser oscillator (including a cylindrical lens, a condenser lens, etc.) and a holding mechanism for holding the processing substrate. The processing substrate held by the holding mechanism is placed under a predetermined gas atmosphere. And a process chamber for placing it in the chamber.

As shown in FIG. 2, a process chamber used in a conventional laser annealing apparatus includes a chamber body 21, a process window 22 attached to an opening formed in the chamber body 21, and a chamber body 21.
Inside the chamber body 21, a rail 23 fixed inside, a stage (holding mechanism) 24 configured to move on the rail 23, a moving mechanism 25 for moving the stage 24 along the rail 23, It has a turbo molecular pump 26 and a dry pump 27 for exhausting.

In this laser annealing apparatus, the processing substrate 28 is introduced into the chamber main body 21 and held (or placed) on the stage 24, and then the chamber main body 21 using the turbo molecular pump 26 and the dry pump 27.
By evacuating the inside, the processing substrate 28 is placed under vacuum. Alternatively, thereafter, while continuing evacuation, a gas such as N ₂ is introduced into the chamber main body 21 and the processing substrate 28 is placed in a gas atmosphere having a predetermined pressure or less. Then, in order to facilitate annealing by the laser beam, the processing substrate is heated to a predetermined temperature and the surface thereof is irradiated with the laser beam. This laser beam is emitted from a laser oscillator (not shown), shaped and condensed by the optical system 29,
The processed substrate 28 is irradiated through the process window 22.

As described above, in the conventional laser annealing apparatus, the annealing using the laser beam is performed.

[0008]

In the conventional laser annealing apparatus, since the laser beam is focused on the surface of the processing substrate with high accuracy, the focusing lens is arranged as close to the processing substrate as possible. Therefore, when the processed substrate 28 is heated, radiant heat is emitted from the surface thereof, and the radiant heat reaches the process window 22 and the condenser lens. The process window 22 and the condenser lens are distorted when the temperature thereof rises, which deteriorates the annealing accuracy of the laser annealing apparatus. Therefore, in the conventional laser annealing device,
Cooling means for cooling the process window 22 and the condenser lens (or the optical system 29) is provided in order to prevent deterioration of the annealing accuracy due to radiant heat from the processing substrate.

However, since the conventional cooling means arranges the cooling water passage around the process window and the condenser lens to circulate the cooling water, it is sufficient when the heating temperature of the processed substrate is high. There is a problem that the cooling effect cannot be obtained, or that it takes a long time to obtain a sufficient cooling effect.

According to the present invention, by blocking the radiant heat from the processing substrate toward the condenser lens, it is possible to suppress the temperature rise of the process window and the condenser lens and prevent the generation of distortion, thereby improving the annealing accuracy. It is an object of the present invention to provide a laser annealing device that can be used.

[0011]

According to the present invention, a laser oscillator for generating a laser beam to be applied to a processing substrate, and a condenser lens for applying the laser beam to the processing substrate. A holding means for holding the processing substrate ; and a holding means built in the holding means and the condensing lens.
A window through which the laser beam is transmitted.
A process chamber provided with the laser annealing apparatus, and a laser annealing apparatus provided with the process chamber provided inside the process chamber.
A heat shield plate that can enter / retract between the condenser lens and the holding unit, and is located outside the process chamber.
Driven through the process chamber and fixed to the heat shield.
A motor having a moving shaft is provided , and the motor is used to shield the
Drive the heat plate to shield / expose the window
The laser annealing device being characterized in that the.

[0012]

[0013]

In the laser annealing apparatus of the present invention, a stainless steel plate can be used as the heat shield plate.

[0015]

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

The laser annealing apparatus according to the present embodiment has a laser oscillator for pulse-oscillating a laser beam, an optical system for shaping the laser beam from the laser oscillator, condensing the laser beam and irradiating it onto a processing substrate, as in the conventional case. And a process chamber for placing the processing substrate in a predetermined atmosphere. Since the laser oscillator and the optical system are the same as those of the conventional one, the description thereof will be omitted and the process chamber will be described in detail below.

FIG. 1 shows a process chamber used in a laser annealing apparatus according to an embodiment of the present invention.

As in the conventional case, the process chamber shown in FIG. 1 has a chamber body 21, a process window 22 attached to an opening formed in the chamber body 21, a rail 23 fixed inside the chamber body 21, and a rail 23. Stage (holding mechanism) 24 configured to move
And a moving mechanism 25 for moving the stage 24 along the rail 23, and a turbo molecular pump 26 and a dry pump 27 for exhausting the inside of the chamber body 21. In addition to the above configuration, this laser annealing device has a heat shield plate (shutter) 11 and a drive motor 12 for driving or moving the heat shield plate 11. Further, this laser annealing device has a cooler (water cooling device, not shown) for cooling the upper surface of the chamber body 21, the drive motor 12, the process window 22, and, if necessary, the optical system 29. .

The heat shield plate 11 is, for example, a plate made of stainless steel, and its surface (the lower surface in the figure) is mirror-finished. The heat shield plate 11 is arranged inside the chamber body 21.

The drive motor 12 is fixed on the outer upper surface of the chamber body 21 and near the process window 22. A through hole for inserting the drive shaft of the drive motor 12 is formed in the chamber body 21, and the drive motor 12 has the drive shaft inserted in the through hole.
And it is fixed while keeping airtightness. 1 of drive motor
The tip of the drive shaft 2 is projected inside the chamber body 21, and the heat shield plate 11 is fixed there.

When the driving motor 12 is driven, the heat shield plate 1
1 moves to occlude and expose the process window 22. In other words, the heat shield plate 11 is the drive motor 1
Driven to 2, stage 24 and process window 22
Enter between and and withdraw from between them. This means that the heat shield plate 11 enters between the optical system 29 (condensing lens) and the stage 24 and retracts from there.

When the process window 22 is shielded by the shield plate 11, the radiant heat from the processing substrate 28 is completely shielded by the shield plate 11 and the process window 2 is closed.
2 cannot be reached. Therefore, the radiant heat from the processing substrate 28 does not reach the optical system 29 (the condenser lens facing the process window 22).

In the laser annealing process, the ratio of the time during which the processing substrate is irradiated with the laser beam is small in the time required for the entire process. That is, a large proportion of the time required for the annealing treatment is the time when the treatment substrate is not irradiated with the laser beam. Therefore, when the drive motor 12 is driven in synchronization with the irradiation of the laser beam to irradiate the processing substrate 28 with the laser beam, the process window 22 is exposed, and while the irradiation of the laser beam is not performed, the heat shield plate is exposed. By blocking the process window 22 with 11, the temperature rise of the condenser lens due to the radiant heat from the processing substrate 28 can be significantly suppressed. As a result, it is possible to suppress the occurrence of distortion in the condenser lens, and perform highly accurate annealing. In this case, it is more effective to cool the condenser lens with a cooler, and highly accurate annealing is possible even when the substrate temperature is higher.

As described above, in the present embodiment, most of the radiant heat traveling from the processing substrate 28 to the condenser lens is blocked by the heat shield plate 11, so that more accurate annealing can be performed. .

Although the heat shield plate 11 is arranged in the chamber body 21 in the above embodiment, it may be arranged outside the chamber body 21 if there is a space.
In this case, the drive motor 12 does not necessarily have to be fixed to the chamber body 21.

[0026]

According to the present invention, the temperature rise of the condenser lens can be suppressed by providing the shield plate which can enter / retract between the condenser lens and the holding mechanism of the laser annealing device. Therefore, the annealing accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a process chamber used in a laser annealing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a process chamber used in a conventional laser annealing apparatus.

[Explanation of symbols]

11 Heat shield 12 Drive motor 21 chamber body 22 Process window 23 rails 24 stages 25 moving mechanism 26 Turbo molecular pump 27 Dry pump

Claims (2)

(57) [Claims] 1. A laser oscillator for generating a laser beam to be irradiated onto a processing substrate, a condenser lens for irradiating the processing substrate with the laser beam, a holding means for holding the processing substrate , Built-in holding means for holding
The laser beam between the means and the condenser lens
In the laser annealing apparatus equipped with a process chamber having a window for the process Cha
A heat shield plate located inside the chamber and capable of entering / retracting between the condenser lens and the holding means; and the process chamber.
Fixed to the outside of the
A motor having a drive shaft fixed to the heat shield plate is provided, the
A motor is used to drive the heat shield to open the window.
A laser annealing device characterized by being shielded / exposed . 2. The laser annealing apparatus according to claim 1 , wherein the heat shield plate is made of stainless steel.