KR20100027270A - Apparatus for light induced chemical vapor deposition - Google Patents

Abstract

PURPOSE: A light induced chemical vapor deposition apparatus is provided to improve the yield and productivity of a semiconductor substrate by including a wide process window and depositing a superior quality of thin film on the semiconductor substrate. CONSTITUTION: A reaction chamber(280) provides a reaction space for a substrate(260) which is placed on a substrate support stand(270). A reactive gas supply unit(230) supplies a reactive gas in the reaction space. A light source unit(210) generates a light. A light irradiation unit(222) decomposes the light by exciting the reactive gas. A charge beam irradiation device(300) forms a beam irradiation unit in a path for the reactive gas.

Description

Apparatus for Light Induced Chemical Vapor Deposition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide chemical vapor deposition apparatus, and more particularly, to a light guide chemical vapor deposition apparatus capable of depositing a thin film of good quality on a substrate while having a wide process window.

With the miniaturization and high integration of electronic devices, there has been a demand for a method of depositing a thin film on a substrate at a relatively low temperature in the electronic device manufacturing technology field compared to other thin film deposition processes. One of such low-temperature thin film deposition methods, Light Induced Chemical Vapor Deposition (LICVD) has been mainly used for depositing a metal film, silicon film, germanium film, and the like on a substrate.

Among them, an example of depositing a hydrogenated amorphous Si (“a-Si: H”) film on a substrate by irradiating a silane (SiH ₄ ) gas with light, particularly a laser beam, is described in D. Metzger, K. Hesch. , and P. Hess, "Process Characterization and Mechanism for Laser-Induced Chemical Vapor Deposition of a-Si: H from SiH ₄ " Appl. Phys. A 45, 345-353 (1988). This paper investigates the dependence of a-Si: H thin film deposition on laser-induced decomposition of SiH ₄ on various process variables. The deposition apparatus used for this study is shown in FIG. 1 is a schematic cross-sectional view showing an example of an apparatus used in the LICVD process according to the prior art. Referring to FIG. 1, the laser beam induced chemical vapor deposition apparatus 100 provides a reaction space 20 surrounded by a chamber wall 10. In the reaction space 20, a reaction gas (eg, SiH ₄ gas in order to deposit a-Si: H thin film) is injected into the substrate 40. The reaction gas is a cylinder having a diameter of several mm. It is injected near the height of the laser beam 30 in parallel with the surface of the substrate 40 through the mold nozzle, or in the direction of the surface of the substrate 40. However, when the thin film is deposited in the laser beam induced chemical vapor deposition apparatus 100 having such a structure, the deposition rate is higher than other processes because the deposition is performed by the vapor phase reaction due to the strong energy injection. The process window is very narrow in order to obtain a thin film of. That is, it is difficult to form a high quality thin film on the substrate 40 when the process parameters such as the temperature in the reaction space 20, the flow rate of the reaction gas, the intensity of the laser light, and the like are controlled within a very strict range. There is this.

Accordingly, an object of the present invention is to provide a light guide chemical vapor deposition apparatus capable of depositing a thin film of good quality on a substrate while having a wide process window.

In order to solve the above problems, the light guide chemical vapor deposition apparatus of the present invention:

A reaction chamber providing a reaction space for the substrate located on the substrate support;

A reaction gas supply unit for supplying a reaction gas into the reaction space;

A light source unit generating light for exciting and decomposing the reaction gas;

A light irradiating part for irradiating the light emitted from the light source to excite the reaction gas into decomposition particles;

A charge beam irradiation device provided to form a beam irradiation section on a path through which the reaction gas passing through the light irradiation section passes to energize or ionize the decomposition particles of the reaction gas passing through the light irradiation section;

It characterized in that to form a thin film on the substrate.

According to the light-induced chemical vapor deposition apparatus of the present invention, since the thin film can be deposited at a high deposition rate on the substrate, productivity is increased in manufacturing an electronic device.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail. The following examples are only presented to understand the content of the present invention, and those skilled in the art will be capable of many modifications within the technical spirit of the present invention. Therefore, the scope of the present invention should not be construed as limited to these examples.

2 is a schematic cross-sectional view of a light guide chemical vapor deposition apparatus 200 according to an embodiment of the present invention. Referring to FIG. 2, not only the structure of the light induced chemical vapor deposition apparatus 200 but an example of forming a silicon (Si) film using SiH ₄ gas as a reaction gas in the deposition apparatus 200 will be described. The substrate 260 on which the thin film is to be deposited is placed on the substrate support 270, and a reaction space for the substrate 260 is provided by the reaction chamber 280. SiH ₄ reaction gas is supplied through the reaction gas supply unit 230, and a quartz window 240 is installed in the middle of the reaction gas supply unit 230 so that the irradiation light 220 from the light source unit 210 can pass therethrough. It is. The light source unit 210 may be selected as long as the irradiated light 220 emitted from itself can excite and decompose the reaction gas, and may include a laser light source unit such as an ArF excimer laser, a KrF excimer laser, a CO 2 laser, or a halogen lamp. It may be a lamp light source of. The irradiation light 220 passes through the quartz window 240 and the space where the reaction gas meets the light irradiation unit 222, where the SiH ₄ reaction gas absorbs energy from the irradiation light 220, as shown in the following formula Decompose

[Formula]

SiH ₄ ---> Si + 2H ₂

The decomposed result forms silicon nanoparticles (Si cluster), and these particles (Si, Si cluster) further pass through the beam irradiator 250. The beam irradiator 250 is made by the charge beam irradiator 300, and specific examples of the charge beam irradiator 300 include an ion beam irradiator or an electron beam irradiator. The charge beam irradiator 300 increases the number of decomposed particles ionized by applying energy to the decomposed particles or ionizing them by impinging the reaction gas primarily decomposed by the irradiation light 220 by beam irradiation. Do it. The charge beam irradiation apparatus 300 includes a charge beam generator 310 for generating a charge beam, a charge lens 312 and a deflection coil 314 for preventing the diffusion of the irradiated charge beam and adjusting its direction. Particles that have passed through the beam irradiation unit 250 made by the charge beam irradiation apparatus 300 include ionized particles of inert gas, particles released from the reaction gas, and the like, for example, Ar +, Si or Si +, Si clusters or ionized particles. Si-cluster etc. can be used. After these particles enter the reaction chamber 280, they are directed onto the substrate 260 to deposit a thin film. However, since the particles entering the reaction chamber 280 are diffused in the reaction chamber 280, the quality of the thin film formed on the substrate 260 if some of them are directed so as to guide the substrate 260. This will be better. Thus, the device of the present embodiment is connected to an device that applies an electric field to the substrate 260 such that ionized particles are attracted to the substrate 260. The electric field applying device includes a mesh type electrode 290 and a power supply 292 connected thereto spaced apart from the substrate 260. One end of the power supply is electrically connected to the electrode 290 in the form of a mesh, and the other end is electrically connected to the substrate support 270 in contact with the bottom surface of the substrate 260. Since the SiH ₄ gas is used as an example of the reaction gas in the apparatus of the present embodiment, in order to attract ionized particles decomposed from the SiH ₄ gas to the substrate 260, the anode of the power supply 292 is connected to the mesh-shaped electrode 290. Naturally, the cathode of the power supply 292 is electrically connected to the substrate support 270, respectively. Here, the shape of the electrode 290 is not particularly limited, but in the case of the mesh shape, even if there are ionized particles in the space 294 between the electrode 290 and the upper wall of the reaction chamber 280, the substrate easily passes through the mesh. Has the advantage of being able to reach 260. In addition, the power supply 292 may include a voltage regulating device to act as an electric field strength adjusting means. If the electric field strength can be adjusted by the voltage regulating device, it is possible to prevent a problem that damage occurs due to the impact of ionized particles having excessive energy on the thin film already deposited on the substrate 260. Although the direct current field applying device is shown in the present embodiment, in addition, when the substrate is non-conductive, an electric field may be added by applying an RF (AC) to form an electric potential difference. no.

3 is a schematic cross-sectional view of a light guide chemical vapor deposition apparatus 300 according to another embodiment of the present invention. Although the light guide chemical vapor deposition apparatus 300 of FIG. 3 and the light guide chemical vapor deposition apparatus 200 of FIG. 2 are similar in most structures, the light guide chemical vapor deposition apparatus 300 of FIG. 230 and the charge beam irradiation device 300 is located on the upper portion of the reaction chamber 280, the reaction gas is supplied to the substrate 260 rather than parallel to the substrate is different. In this case, since the decomposition particles of the reaction gas approach the substrate 260 by themselves with momentum, it may be helpful to form a thin film of better quality than the apparatus shown in FIG. 2. In this case, an electrode for inducing the ionized decomposed particles to the substrate 260 may be unnecessary, but if the electrode must be provided so that the ionized decomposed particles can approach the substrate 260 at a controlled speed, the electrode shown in FIG. As shown in the drawing, the mesh type electrode 290 should be installed to prevent the ionized decomposition particles from being shielded by the electrode and not being induced toward the substrate 260.

4 is a schematic cross-sectional view of a light induced chemical vapor deposition apparatus 400 according to another embodiment of the present invention. Although the light guide chemical vapor deposition apparatus 400 of FIG. 4 and the light guide chemical vapor deposition apparatus 300 of FIG. 3 are similar in most structures, in the light guide chemical vapor deposition apparatus 400 of FIG. 230 and the charge beam irradiation device 300 is located on the upper portion of the reaction chamber 280, they are installed separately, the ion beam or electron beam from the charge beam irradiation device 300 is inclined toward the substrate 260 The difference is that it is scanned and encounters the decomposition products of the reaction gas slightly above the substrate 260. Therefore, in the light guide chemical vapor deposition apparatus 400 according to the present embodiment, the amount of energy applied by the charge beam irradiator 300 to the decomposition material of the reaction gas is relatively large and the degree of ionization is also increased, whereas the charge beam generator ( The strength of 310 must be precisely controlled to prevent damage to the substrate 260 due to charge beam impact. In addition, the device 400 of the present embodiment is characterized in that the cathode of the power supply 292 is connected to the substrate 260 and the anode of the power supply 292 is grounded so that a separate mesh type positive electrode is not provided in the reaction chamber. It is preferable to move the charge beam generator 310 or to move the substrate 260 so that the deposition may be performed in the form of scanning the substrate 260. In FIG. 4, a driving device for deposition by scan is not separately illustrated.

When using the apparatus according to the embodiment of the present invention shown in Figures 2 to 4, if the reaction gas is SiH ₄ gas, depending on the process conditions in the high quality amorphous silicon film (a-Si film) nanocrystal silicon film (nc -Si film), microcrystalline silicon film (uc-Si film), polycrystalline silicon film (poly-Si film), and the like can be deposited. In addition, since the decomposition particles of the reaction gas may have sufficient energy in the charge beam irradiation apparatus, the process may be performed in a wide process window.

1 is a schematic cross-sectional view showing an example of an apparatus used in the LICVD process according to the prior art;

2 is a schematic cross-sectional view of a light guide chemical vapor deposition apparatus according to an embodiment of the present invention;

3 is a schematic cross-sectional view of a light guide chemical vapor deposition apparatus according to another embodiment of the present invention; And

4 is a schematic cross-sectional view of a light guide chemical vapor deposition apparatus according to another embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

200, 300, 400: light guide chemical vapor deposition apparatus 210: light source unit

220: irradiation light 222: light irradiation unit

230: reaction gas supply unit 240: quartz window

250: beam irradiation unit 260: substrate

270: substrate support 280: reaction chamber

290: electrode 292: power supply

294: space between the electrode and the top wall of the reaction chamber

300: charge beam irradiation apparatus 310: charge beam generator

312: charge lens 314: deflection coil

Claims (9)

A reaction chamber providing a reaction space for the substrate located on the substrate support; A reaction gas supply unit for supplying a reaction gas into the reaction space; A light source unit generating light for exciting and decomposing the reaction gas; A light irradiating part for irradiating the light emitted from the light source to excite the reaction gas into decomposition particles; A charge beam irradiation device provided to form a beam irradiation section on a path through which the reaction gas passing through the light irradiation section passes to energize or ionize the decomposition particles of the reaction gas passing through the light irradiation section; Light-induced chemical vapor deposition apparatus having a thin film formed on the substrate. The apparatus of claim 1, wherein the reaction gas supply unit and the charge beam irradiator are positioned above the reaction chamber so that the reaction gas is supplied toward the substrate. The light guide chemical vapor deposition apparatus according to claim 1 or 2, wherein the light source unit is a laser light source unit or a lamp light source unit such as halogen. The light induced chemical vapor deposition apparatus according to claim 1 or 2, wherein the charge beam irradiating apparatus is an ion beam irradiating apparatus or an electron beam irradiating apparatus. The apparatus of claim 1 or 2, wherein an electric field applying device is connected to the substrate such that ionized decomposition particles entering the reaction chamber through the beam irradiator are attracted to the substrate. The apparatus of claim 5, wherein the electric field applying apparatus comprises an electrode installed on an upper portion of the substrate and a power source connected thereto. The apparatus of claim 6, wherein the electrodes spaced apart from each other on the substrate have a mesh shape. The apparatus of claim 1, wherein the charge beam irradiator is installed such that the beam irradiator is located in the reaction chamber. The apparatus of claim 8, wherein the charge beam irradiator is capable of depositing the entire surface of the substrate while scanning.

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