JPH05304106A - Excimer laser annealer - Google Patents

Abstract

PURPOSE:To provide an excimer laser annealer in which metallic contamination of a silicon wafer to be annealed due to susceptor is suppressed. CONSTITUTION:The excimer laser annealer comprises an excimer laser oscillator 1, an optical system 2, and a process chamber 4 having a metallic material supporting base 5 for mounting a light transmissive insulating material window 6 and a semiconductor wafer 10 to be irradiated with laser beam, wherein a light shielding board 11 for shielding the exposed supporting table 5 at least on the periphery of the semiconductor wafer is disposed between the light transmissive insulating material window 6 and the semiconductor wafer 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excimer laser annealing apparatus, and more particularly to an excimer laser annealing (EL) for preventing contamination of a semiconductor wafer by a support (susceptor) material on which the semiconductor wafer is placed.
A) It relates to the device.

[0002]

2. Description of the Related Art Currently, excimer lasers (EL) are mainly L
Development studies are being conducted on annealing in a polysilicon TFT (thin film transistor) for a CD (liquid crystal display device), annealing as a junction forming technique compatible with a 0.2 μm (micron) size MOS FET, and the like.

FIG. 4 is a schematic diagram showing the structure of a conventional excimer laser annealing (ELA) apparatus.

As shown in FIG. 4, a conventional ELA device includes a laser oscillator 1 for oscillating a predetermined excimer laser, an optical system 2 for converging and polarizing a laser beam 1a oscillated from the excimer laser oscillator 1, and an optical system. Laser light 1 emitted from 2
It is mainly composed of a mirror 3 for reflecting a and a process chamber 4 in which a semiconductor wafer 10 to be processed (annealed) is placed and housed.

In the process chamber 4, a silicon wafer 10 is placed on a susceptor 5 made of metal such as stainless steel as a support, and a transparent quartz window 6 is provided at the laser light inlet above the silicon wafer 10. It is provided.

[0006]

The conventional E shown in FIG. 4 is used.
In the LA device, the excimer laser directed to the silicon wafer 10 through the quartz window 6 generally has a high pulse energy density of 200 mJ / cm ² or more, and as shown in FIG. In some cases, the metal surface of the susceptor 5, which is a support, is heated, and the components in the metal are mixed and contaminated (metal contamination) in the silicon wafer 10 through the solid phase, the liquid phase, and the gas phase.

In the future, as the output of the laser device increases and the laser beam area increases, the problem of metal contamination on the silicon wafer increases.

Therefore, an object of the present invention is to provide an excimer laser annealing apparatus which reduces metal contamination from a susceptor on a silicon wafer to be annealed.

[0009]

According to the present invention, the above-mentioned problems are solved by an excimer laser oscillator, an optical system for converging and polarizing the laser light oscillated from the excimer laser oscillator, and a laser via the optical system. In an excimer laser annealing apparatus comprising a process chamber having a light-transmissive insulating material window through which light passes and a metal material support on which a semiconductor wafer to be irradiated with laser light is mounted, the light-transmissive insulating material window and The excimer laser annealing apparatus is characterized in that a light shielding plate that shields at least the exposed support base surface around the semiconductor wafer is provided between the semiconductor wafer and the semiconductor wafer.

Further, according to the present invention, the above-mentioned problem is an excimer laser oscillating device, an optical system for converging and polarizing the laser light oscillated from the excimer laser oscillating device, and light passing through the optical system. In an excimer laser annealing apparatus including a process chamber having a transparent insulating material window and a metal material supporting base on which a semiconductor wafer to be irradiated with laser light is mounted, the surface of the metal material susceptor is made of the same material as the semiconductor wafer. It is solved by an excimer laser annealing apparatus characterized by being coated with.

[0011]

According to the present invention, as shown in FIG. 1, a quartz window 6 as a light-transmissive insulating material window is provided in the process chamber 4.
And a silicon (Si) wafer 10 as a semiconductor wafer to be annealed (laser irradiation), the Si wafer 10
A light shield plate (light shield ring) 11 is provided to shield the periphery of itself and the exposed susceptor (support) surface around the Si wafer 10. Therefore, the excimer laser light emitted from the quartz window 6 in a direction substantially perpendicular to the direction of the Si wafer 10 is shielded by the light shielding plate 11, and the metal susceptor is irradiated and reduced in heating. Therefore, the metal of the susceptor material becomes less likely to enter the Si wafer 10 in the vapor phase, and metal contamination is suppressed.

In the present invention, it is preferable that the opening inside diameter of the laser passage portion of the light shielding plate 11 is smaller than the outside diameter of the Si wafer so that the susceptor around the Si wafer is not reliably irradiated with the laser light. The material of the light shielding plate 11 is preferably the same as the material of the target semiconductor wafer 10, for example, silicon in the case of a silicon wafer.

Furthermore, according to the present invention, as shown in FIG. 3, the surface of the metal susceptor 5 on which the semiconductor wafer 10 is mounted is coated with the same material as that of the semiconductor wafer 10 to prevent the metal contamination. Is suppressed as well.

[0014]

EXAMPLES Hereinafter, the excimer laser annealing (E
An embodiment of the LA) device will be described with reference to the drawings.

FIG. 1 is a schematic view showing an embodiment of the constitution of the ELA device of the present invention. The ELA device of the present invention shown in FIG. 1 has an optical shield ring 11 made of silicon between a quartz window 6 and a silicon (Si) wafer 10 in the process chamber 4 of the conventional ELA device described in FIG. The configuration is the same as that of the conventional ELA device except that it is attached.

That is, as shown in FIG. 1, the EL of the present invention
The apparatus A is an excimer laser oscillator 1, an optical system 2, a mirror 3, and a process chamber 4 having a quartz window 6, a light shield ring 11 and a susceptor 5 for mounting a wafer 10.
Consists of.

In the light shield ring 11, as shown in FIG. 2, the outer diameter of the Si wafer 10 is φ ₁ , and the light shield ring 1 is
A hole of φ ₁ <φ ₂ is provided as the inner diameter φ ₂ of ₁ . Normally, the laser light is applied as a surface beam almost perpendicularly to the surface of the Si wafer.

Therefore, if the light shield ring under the above conditions is used, the laser light does not hit the susceptor on which the silicon wafer is placed, and the contamination by the metal or the like forming the susceptor is reduced.

As a material of the light shield ring 11, the above S
In addition to i, a material coated with Si can be used. When the upper surface of the light shield ring 11 was irradiated with laser light, the Si surface was roughened by polishing in order to suppress reflection (diffuse reflection).

FIG. 3 is a schematic view showing another excimer laser annealing apparatus of the present invention.

As shown in FIG. 3, this embodiment is an apparatus in which the surface of a susceptor (metal) 5 is coated with silicon by a thickness of about 0.5 μm in the conventional excimer laser annealing apparatus shown in FIG.

The material of the coating portion 12 is silicon (S
The reason for i) is that the semiconductor wafer to be laser annealed is a silicon wafer, and therefore the material is the same.

The silicon coating portion is indicated by 1 in FIG.
2, the silicon coating portion 12 is formed by the CVD method. Although the thickness of the Si coating 12 is 0.5 μm in this embodiment, it is 100 angstroms or less for antireflection and practical reasons.
5 μm is preferable.

[0024]

As described above, according to the present invention, when excimer laser annealing the surface of a semiconductor wafer, metal contamination of the wafer from the susceptor supporting the wafer is reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of the configuration of an excimer laser annealing (ELA) apparatus of the present invention.

FIG. 2 is a top view and a side view of a shield ring for laser shielding according to the present invention.

FIG. 3 shows another excimer laser annealing (EL
FIG. 3A is a schematic diagram showing an example of the configuration of an apparatus.

FIG. 4 is a schematic diagram showing a configuration of a conventional ELA device.

FIG. 5 is a schematic diagram for explaining metal contamination on a silicon wafer.

[Explanation of symbols]

 1 Laser Oscillator 1a Laser Light 2 Optical System 3 Mirror 4 Process Chamber 5 Susceptor (Metal) 6 Quartz Window (Light-Transparent Insulating Material Window) 10 Silicon (Si) Wafer (Semiconductor Wafer) 11 Light Shield (Light Shielding Plate) 12 Silicon (Si) coating part

Claims (4)

[Claims] 1. An excimer laser oscillator, an optical system that converges and polarizes laser light emitted from the excimer laser oscillator, and a light-transmissive insulating material window and laser light through which the laser light passes through the optical system. In an excimer laser annealing apparatus comprising a process chamber having a metal material support on which a semiconductor wafer to be irradiated is mounted, between the light transmissive insulating material window and the semiconductor wafer,
An excimer laser annealing apparatus comprising a light shielding plate that shields at least the exposed support surface around the semiconductor wafer. 2. The excimer laser annealing apparatus according to claim 1, wherein an inner diameter of an opening of the light shielding plate is smaller than an outer diameter of the semiconductor wafer. 3. The excimer laser annealing apparatus according to claim 1, wherein the same material as that of the semiconductor wafer is used as the surface material of the light shielding plate. 4. An excimer laser oscillator, an optical system for converging and polarizing laser light oscillated from the excimer laser oscillator, and a light-transmissive insulating material window and a laser through which the laser light passes through the optical system. In an excimer laser annealing apparatus provided with a process chamber having a metal material support on which a semiconductor wafer to be irradiated with light is mounted, the surface of the metal material susceptor is coated with the same material as the semiconductor wafer. Excimer laser annealing equipment.