JPS62263643A - Method and apparatus for manufacturing silicon nitride film using laser beam - Google Patents

Abstract

PURPOSE:To obtain a film having excellent uniformity including a refractive index, density, etc. by irradiating a raw material by optimum energy density and energy input and smoothly promoting a chemical reaction. CONSTITUTION:A substrate is mounted horizontally under the environment of pressure of 0.2Torr-100Torr and a temperature of 100-500 deg.C while an silicon compound and a nitrogen compound are introduced under the environment, the surface of the substrate is irradiated horizontally by tunable pulse laser beams having a wavelength of 215+ or -7nm and repeated number of 20+ or -10Hz, and an silicon nitride film is formed onto the substrate. The rate of film formation is decreased when pressure reaches less than 0.2Torr, and particulates are generated partially and are disadvantageous to film formation. An excellent film cannot be shaped when a temperature is less than 100 deg.C, and the state in which stress is applied to the film formed is brought when the temperature exceeds 500 deg.C. A laser such as a YAG-DYE laser can be used as a light source for tunable laser beams employed.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention is directed to CVD (Chemical Vapo
This article relates to a method and apparatus for manufacturing a filtering film using the DcpoSition method, and more specifically relates to semiconductor manufacturing, and in particular, to manufacturing a silicon nitride film as a transistor film such as an LSI insulating film or a protective film using a laser beam. This is related to the method and equipment used to manufacture the product.

"Prior art" Conventionally, silicon nitride films have been manufactured as described in, for example, JP-A-57-2.
The method described in Japanese Patent Application Laid-open No. 1/736 and Japanese Patent Application Laid-Open No. 59-231819 was used.

That is, while irradiating the substrate with a mercury lamp, xenon lamp, plasma, or excimer laser, SiIII
A silicon compound such as 4s S i 2 II a, 5i1/tCI22, and N1/. , LI+, etc. nitrogen compounds,
Furthermore, there is a method of forming a silicon nitride film on the substrate by supplying an inert gas such as N2, Ar, or lle.

"Problems to be Solved by the Invention" By the way, the conventional method for manufacturing a silicon nitride film has the following problems, and it is desired to solve them.

(a) This is particularly noticeable in the mercury lamp method, but a film cannot be formed at low temperatures. In addition, the film formation rate is slow at the beginning.

(b) With the plasma method, the film formation rate is fast, but the film quality (
density, refractive index) are poor.

(C) With lasers, especially excimer lasers, the lifetime of the laser beam is extremely short, making it impossible to form a continuous and stable film.

(d) Co2 laser, excimer laser-1 and other laser methods and optical lamp methods require a window plate to irradiate the inside of the reactor with the laser or light, but this window plate material may become cloudy and Due to the cloudiness, the irradiation amount decreases and the film formation rate slows down.

(a) Laser method, lamp method, especially lamp method:
Since the irradiation shape is limited, it is not possible to form a large-capacity film on many substrates of various sizes at once.

(``) Because the film must be formed at high temperatures, stress is applied to the film after it is formed, reducing its strength and lifespan.

This invention was made in view of the above-mentioned circumstances, and its purpose is to use a laser beam to reduce temperature without increasing the temperature.
An object of the present invention is to provide a method and apparatus for manufacturing a silicon nitride film that can efficiently form stress-free, high-quality silicon nitride films on a wide variety of substrates.

"Means for Solving the Problems" The present inventors have discovered a nitride film that can solve the above-mentioned conventional problems and efficiently form stress-free, high-quality silicon nitride films on a wide variety of substrates. As a result of intensive research in order to obtain a method and apparatus for manufacturing a silicon film, the following knowledge was obtained.

When forming a film using a laser beam, the film can be formed at a relatively low temperature, but as mentioned above, (c) the lifespan of the laser beam is extremely short, making it impossible to form a stable film continuously. , (d) The product inside the reactor adheres to the window plate material used to guide the laser into the reaction 2: ÷ inside, causing fogging, which reduces the irradiation amount and slows down the film formation rate. Furthermore, although the lamp method is not so obvious, (e) the irradiation shape is limited, so it is not possible to form a large-capacity film on many substrates of various sizes at once. There is a drawback.

However, it has been found that these drawbacks can be overcome by the following means.

First, the drawback of (C) can be solved by using a wavelength tunable laser as the laser beam. It has become clear that a high-quality pattern can be formed by setting the laser beam to a wavelength of 215±7 nm and a repetition rate of 20±1 OII z.

It has also been found that the drawback (e) can be solved by horizontally irradiating the substrate surface with this pulsed laser.

Furthermore, regarding the drawback of (d), the window for laser beam transmission that was conventionally formed on the end face of reaction 2: was replaced by a short tube protruding from the end face of the reactor, and a transparent window was formed on the end face of the short tube. It was found that the problem could be solved by forming the reactor by pasting a plate to prevent the products generated in the reactor from reaching the number of windows.

This invention was made based on the above knowledge.

That is, the method of manufacturing a silicon nitride film using a laser beam of the present invention includes: a pressure of 0.2 Torr to 100 Torr and a temperature of 100°C to
A wavelength variable pulse with a wavelength of 215±7 nx and a repeating number of 20±1 OL was created by installing a substrate horizontally in an environment of 500°C and introducing a silicon compound and a nitrogen compound into this environment.

A silicon nitride film is formed on the substrate by horizontally irradiating the substrate surface with a laser beam, and the silicon nitride film manufacturing apparatus using the laser beam of the present invention further includes: In addition to having a stand on which the substrate is placed horizontally, a reaction gas introduction pipe for introducing silicon compound gas and nitrogen compound gas into the inside is provided on the side, and the inside is heated to at least 0.2 Torr and 500°C. You can set
a reactor having at its end a short tube with a transparent window for passing a laser beam;
±7na, pulsed laser with repetition rate 20+1OHz
It is equipped with a wavelength tunable laser transmitter that emits light beams at different wavelengths.

In the above configuration, the pressure is set to 0.2 Torr to 1 OQT.
The reason why it was set to 0.2 Torr is that the film formation rate slows down and becomes disadvantageous when the Torr is less than 0.2 Torr.
This is because if the temperature exceeds OTorr, part of the fine particles will be generated, which will be disadvantageous for forming a thin film.

In addition, the temperature was set between 1000C and 500C.
This is because good film formation cannot be achieved at temperatures below 00°C.
This is because if the temperature exceeds 00°C, the formed film will be under stress.

Further, as a light source of the wavelength tunable laser beam used in the present invention, for example, a YAG-DYE laser can be used.

In addition, in the apparatus of the present invention, in order to obtain a good effect from the windowed short tube provided so that the window for laser beam transmission does not fog, the following dimensional limitations are necessary. That is, the length of the short tube is 1/1 to 1/50 of the length of the reactor main body.
Therefore, it is necessary that the diameter of the transparent plate of the window of the short tube is 3 to 40 times the thickness of the transparent plate. These numerical limits were set in order to set the laser transmittance of the transparent window plate material and the difficulty of adhesion of reaction products to the window to desired values.

Furthermore, as the silicon compound used in the present invention,
Mainly 5il14, 5itele, S i 31! a
, 5illtCL, and 5i1/4cQt, and the nitrogen compounds are mainly N , , N II 3 , N , II .

A compound selected from the group of IFIi or higher is used, and in order to form a good film, the ratio between these compounds (N/
It is desirable that the Si ratio is 1 to 25.

"Actions" According to the method and apparatus of the present invention having the above configuration, the following effects can be obtained.

(b) It is possible to irradiate the raw material with optimal energy density and energy power, allowing the chemical reaction to proceed smoothly, thereby making it possible to obtain a film with good uniformity, including refractive index and density. The membrane speed is fast.

(b) Since the film can be formed at a relatively low temperature, no stress is applied to the formed film.

(c) Since a variable wavelength laser can be used to continuously supply a stable laser beam over a long period of time, continuous film formation is possible.

(iv) Since a short tube with a window is attached to the reactor to prevent the window plate from fogging, effective irradiation of the laser beam can be performed continuously and highly efficient film formation is possible.

(e) Since the laser beam is irradiated horizontally onto the substrate surface, a large amount of film can be formed at once, and moreover, it is possible to form a film on any size of substrate.

Examples of the present invention will be shown below.

[Example 1] Figure 1 shows an example of a production apparatus suitable for carrying out the method of the present invention, and the reference numeral l in the figure indicates a reactor.
This reactor l consists of a reactor main body 2 and short pipes 3.1/h attached to both ends of this reactor main body 2, respectively.
M has been completed.

The reactor main body 2 is formed, for example, in a cylindrical shape, and its axial direction is positioned horizontally. A table 6 for horizontally placing the substrate 5 is provided at the center of the interior of the reactor body 2, and a heater 7 is built into the table 6. Above this table 6 is a reaction gas introduction pipe 8 for introducing a reaction gas such as a nitrogen compound or a silicon compound into the reactor 1.
is attached, and an exhaust pipe 9 is attached below the reactor 6 to reduce the pressure inside the reactor 1 to at least 0.2 Torr.

Further, the short tubes 3.4 attached to both ends of the reactor main body 2 are each attached to the center of both end faces of the reactor main body 2, and each open end is provided with a transparent quartz plate (
Transparent window absorbing material) 10a, lla are attached to the window 10, I
It is I. Also, on the sides of these short pipes 3.4,
N2. in each reaction 2'A I. Ar.

A purge gas pipe 12.13 for introducing and discharging part gas such as 1/e is attached.

According to the above structure, the length of the short tube 3.4 is the length of the reactor body 2.
171 to 1/50 of the length of the short tube 3.4 window 1O1/
1 quartz plate 10a, the diameter dimension of lla is the same quartz plate 10a
, lla is required to be 3 to 40 times the thickness dimension in order to perform good film formation using this apparatus, as described above.

The curved blade of one short pipe 3 of the reactor 1 having the flif structure is as follows:
A variable wavelength laser oscillation device 14 is installed, and is configured to irradiate two sides of the substrate 5 with a pulsed laser beam in the direction of ζ into the reactor 1 through a condensing and collimating lens group 15. . This wavelength tunable laser oscillation device 14 is a YAG-
Consists of DYE laser, wavelength 2+5±7n
It is possible to irradiate a pulsed laser beam with a repetition rate of 20±l Otl z.

Using an apparatus with such a structure, a silicon nitride film is formed on a substrate by varying the wavelength, number of pulse repetitions, reaction temperature, pressure, and raw materials used, and the components of the formed film are
The characteristics of the material were measured. These six examples will be shown below.

“Example 1j Wavelength 215nx, number of repetitive pulses 20 II z ,
Reaction temperature 1500c, pressure 40Torr, raw material Si
It, and NII, 1 (Ni1./5i1/, =
A nitride film was formed under the conditions of 17.5). At the same time, for comparison, a nitride film was also formed using the conventional mercury Lang method under the same conditions, and its properties were measured. The results are shown in Table 1.

[Table 1] "Example 2" Wavelength 219na, number of repeated pulses 10 II z ,
Reaction temperature: 250°C, pressure: 20 Torr, K material: Si, I
t, and N1/n (NI+3/Sit+1.=IO)
A nitride film was formed under these conditions. At the same time, for comparison, a nitrided desert was formed using the conventional laser method under the same conditions, and its properties were measured. The results are shown in Table 2.

[Table 2] "Example 3" Wavelength 209nx, repetition pulse number 201/z, reaction temperature 275°C, pressure 100Torr, raw material 5illtc (
! 2 and ~2+1. (N.

A nitride film was formed under the following conditions: II, , /S+1Izc12t = 18).

The results are shown in Table 3.

[Table 3] “Example 1/j Wavelength 22 On, a, Repulse pulse length 10 II z
, reaction temperature 275°C, pressure 40 Torr, raw material Si, I
t, and old! 3(Nll:+, /5i21/, =17
) A nitride film was formed under the following conditions. The results are shown in 224.

[Table 4] "Effects of the Invention" As mentioned above, according to the manufacturing power θ4 and the device]1/ of the silicon nitride film using the laser beam according to the present invention,
Is it possible to get a fl1 point like the one below?

(b) It is possible to irradiate the raw material with optimal energy density and energy power to smoothly proceed with the chemical reaction, thereby making it possible to obtain a film with good uniformity including refractive index and density. The membrane speed is fast.

(b) Since the film can be formed at a relatively low temperature, no stress is applied to the formed film.

(c) Since a variable wavelength laser can be used to continuously supply a stable laser beam over a long period of time, continuous film formation is possible.

(d) Since a short tube with a window is attached to the reactor to prevent the window plate material from fogging up, continuous and effective laser beam irradiation can be performed and highly efficient film formation is possible.

(e) Since the laser beam is irradiated horizontally onto the substrate surface, a large amount of film can be formed at once, and therefore, it is possible to form a film on any size block.

[Brief explanation of drawings]

The figure is a configuration diagram of an example of an apparatus suitable for carrying out the method of the present invention. l-...Reactor, 3.4...Short tube, 5...Jlr; plate, 6...Stand, 7...Heater, 8...Reaction gas introduction pipe, 9...Exhaust pipe, 1O1/1...Window, 10a, 1la-quartz temporary (transparent window plate I, t), 12.
13... Purge gas pipe, 14... Tunable wavelength laser oscillation device, 15... Condensing and collimating lens group.・IX;・-,゛2(s゛, 1/'

Claims (4)

[Claims] (1) Pressure 0.2T0rr~100Torr, temperature 10
A substrate is placed horizontally in an environment of 0°C to 500°C, a silicon compound and a nitrogen compound are introduced into this environment, and a variable wavelength pulsed laser beam with a wavelength of 215 ± 7 nm and a repetition rate of 20 ± 10 Hz is applied to the substrate surface. 1. A method for manufacturing a silicon nitride film using a laser beam, which comprises irradiating the laser beam horizontally to form a silicon nitride film on the substrate. (2) The silicon compound is SiH_4, Si_2H_6, Si
_3H_8, SiH_2cl_2, SiH_4cl_2
one or more compounds selected from the group of
2. The method for producing a silicon nitride film using a laser beam according to claim 1, wherein the compound is one or more compounds selected from the group consisting of _2, NH_3, and N_2H_4, and has an N/Si ratio of 1 to 25. (3) It has a stand on which the substrate is horizontally placed inside, and a reaction gas introduction pipe for introducing silicon compound gas and nitrogen compound gas into the inside is provided on the side, and the inside is set at zero.
Can be set to 2 Torr or less and 500°C or more,
A reactor having a short tube at its end with a transparent window for passing a laser beam, and a laser beam passing through the window of the short tube parallel to the substrate surface with a wavelength of 215±7 nm and a repetition rate of 20.
A device for manufacturing a silicon nitride film using a laser beam, comprising a laser transmitter that irradiates a pulsed laser beam with a variable wavelength of ±10 Hz. (4) The length of the short tube is 1/1 to 1/5 of the length of the reactor body
4. The apparatus for producing a silicon nitride film using a laser beam according to claim 3, wherein the diameter of the transparent plate of the window of the short tube is 3 to 40 times the thickness of the transparent plate.