JPH07105346B2 - Radical beam photo CVD equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention mainly relates to a radical beam photo-CVD apparatus applied to the production of high-density integrated and high-performance semiconductor devices.

(Prior Art) Conventionally, as a method of manufacturing a semiconductor device, a reaction gas is introduced into a vacuum processing chamber in which a substrate is provided, and the components of the reaction gas decomposed by irradiating the substrate with light are formed into a thin film on the substrate. There are known a photo-CVD method and a radical-beam CVD method in which radicals obtained by decomposing a reaction gas are applied in a beam shape on a substrate in a processing chamber to form a thin film thereon.

(Problems to be Solved by the Invention) The above-mentioned optical CVD and radical beam CVD are respectively developed as a technique for manufacturing high-density integrated semiconductor devices at particularly low temperature and low damage. Although there is an advantage that the film is not damaged by the charged particles as seen, the film forming temperature is not so low that the film forming speed is slower than that of plasma CVD or the like. For example light C
The VD method has a relatively low film formation temperature, but the radical CVD method has an effective process temperature of 500 to 600 ° C.
Although lower than the D method, it is high at the required temperature and easily causes substrate damage. Further, the film forming rate is 100 Å / min on average in the photo-CVD method and 2.0 Å / min in the radical CVD method, both of which are about 1 to 2 orders of magnitude lower than those of the plasma CVD method and the thermal CVD method. In such a situation, in the photo-CVD method, radical generation by light irradiation is very selective and the amount of radical generation is small, and in the radical-beam CVD method, only radicals are used as precursors for film formation. This is due to its low activity against formation and nuclear growth. Therefore, it is difficult to practically form a film by using only the optical CVD method or only the radical beam CVD method.

An object of the present invention is to provide an apparatus capable of forming a film at a low temperature and relatively quickly.

(Means for Solving Problems) According to the present invention, a vacuum decomposition chamber in which a reaction gas is decomposed by plasma discharge or the like to generate radicals, and a vacuum film formation provided with a substrate on which a film formation process is performed. A chamber and the radicals generated in the decomposition chamber are introduced into the film forming chamber, the decomposition chamber and the film forming chamber are connected via a number of orifices, and A magnet that removes charged particles other than radicals passing through the orifice and forms a magnetic field intersecting the central axis of the orifice is provided, and a light source provided outside the film deposition chamber passes through a window of the film deposition chamber. Then, light for exciting the surface reaction of the substrate in the chamber to excite and ionize the radicals is introduced to achieve the above-mentioned object.

(Operation) When, for example, SiH ₄ gas is introduced into the decomposition chamber and a plasma discharge is generated, the gas is ionized to generate ions, electrons, radicals, etc. The generated radicals are formed into a beam by an orifice. Introduced into the room. The entry of charged particles other than radicals into the orifice is removed by the action of a magnetic field, and when the radicals in the film formation chamber are excited and ionized by irradiation with light from a light source, the surface reaction of the substrate is excited by the light source. It adheres to the surface like a film. Since radicals have unpaired electrons, they are much more reactive than the parent molecule, and when these are pushed up by light irradiation to a highly excited or ionized state, they give the appropriate activation energy necessary for film formation. Such a highly excited state or ionized state of radicals lowers the critical condensation pressure during nucleation, promotes nucleation and nucleus growth, and increases the trapping cross section of attached molecules on the substrate surface.

Therefore, according to this apparatus, a dense and highly uniform film can be formed at a low temperature, and at the same time, the growth rate of the film can be greatly increased, and further, the parent film that has not been decomposed in the decomposition chamber can be formed. The molecules can be decomposed by light in the film forming chamber to generate radicals, and the parent molecule can be effectively used. Also, if you change the energy of the light to irradiate,
The components adsorbed on the substrate surface can be controlled, and selective film formation can be performed.

(Example) An example of the present invention will be described based on the attached sheet.

The first embodiment shown in the figure shows an example in which the reaction gas of SiH ₄ is decomposed by RF discharge to form a Si film on the substrate. In the figure, reference numeral (1) is the decomposition of the reaction gas. Chamber, (2) exhaust hole (2a) where substrate (3) is installed and is connected to vacuum pump
A film forming chamber (4), which connects the decomposition chamber (1) and the film forming chamber (2) to evacuate the decomposition chamber (1) and forms radicals generated in the chamber (1) into a beam. An orifice (5) introduced into the film forming chamber (2) is a magnet for removing charged particles other than radicals that have passed through the orifice (4).

A high frequency coil (6) and a magnet (7) for forming a circular magnetic field are arranged around the decomposition chamber (1), and the decomposition chamber (1) is disposed.
An inlet (8) for the reaction gas of SiH ₄ is provided at one end of
The film forming chamber (2) is vacuum-sealed at the other end to form a series. The high frequency applied to the high frequency coil (6) is an inductively coupled high frequency (13.56MHZ), and the magnet (7) has about 800 gauss to increase the concentration of radicals generated in the decomposition chamber (1). A circular magnetic field was used. The decomposition chamber (1)
The plasma formed inside is concentrated on the central axis of the decomposition chamber (1) by the action of the circular magnetic field by the magnet (7), so that the reaction with the inner wall of the decomposition chamber (1) is suppressed and the radical concentration is increased. It The orifices (4) are formed so that a large number of them are evenly arranged, and the radicals generated in the decomposition chamber (1) enter the film formation chamber (2) through each orifice (4). I was guided. The orifice (4)
By separating the decomposition chamber (1) and the film formation chamber (2) with
It is possible to reduce that the charged particles generated during the discharge directly hit the substrate (3) and damage it. Multiple orifices (4)
By uniformly arranging and forming, it is possible to obtain uniformity of film formation. (9) is a quartz Teflon coating coated on the surface of the orifice (4) to prevent the radicals introduced from the decomposition chamber (1) into the film formation chamber (2), and (10) is the substrate (3) to be treated. ) Supporting a substrate (1) with a conduit (11) provided inside the holder (1).
The heat medium is supplied to the (0).

Since the particles passing through the orifice (4) contain high-energy electrons and ions, they are removed by the permanent magnet (5), and only neutral radicals can be taken out to the film forming chamber (2). I did it.

(12) is a light source (1) toward the substrate (3) in the film formation chamber (2)
3) Shows a window through which the light rays of (14) and (15) are introduced, and the light of each light source is used for ionizing radicals, decomposing the parent molecule SiH ₄ and exciting the surface reaction of the substrate. The light source (13) for ionization of radicals is SiHn produced by discharge decomposition of SiH _4.
(N = 0 to 3) Radical ionization potential is 7.4
Since it is ~ 9.5 eV, the resonance lines of Xe and Kr are most suitable. Therefore, as a transparent window (12) so that these lights can be transmitted.
LiF, MgF ₂ or CaF ₂ is used. Further, in order to make the ionization of radicals moderate and proper, the degree of focus is changed using lenses having various focal lengths, and light is introduced into the film forming chamber. A light source (14) for photodecomposition of SiH ₄ is introduced from the side opposite to the light source (13), and 150 for decomposition of SiH _4.
~ 160nm light is effective, excimer laser, (ArF)
Or Xe resonance line is used. For excimer lasers,
Power of about 10 MW / cm ² or more is required for efficient decomposition. Furthermore, if a KrF (249 nm) excimer laser is used as the light source (15) for exciting the surface reaction of the substrate (3), the film can be efficiently formed.

In the device shown in FIG. 1, the 1 mm orifice (4) has 7
When the flow rate Q is 40 sccm for each piece, the pressure in the decomposition chamber (1) is 6.2 × 10 ² Pa (4.66 Torr). When the effective evacuation speed of the film forming chamber (2) is 2 / s, the pressure in the chamber (2) is 34 Pa.
(0.25 Torr), which is a commonly used plasma CV
The pressure can be made almost the same as the process condition of D, and by effectively introducing the radicals into the chamber (2), a film formation rate similar to that of plasma CVD can be obtained, and a low deposition rate of about 200 ° C. similar to that of optical CVD can be obtained. The film can be formed at the film temperature. The deposition rate of amosphal silicon deposited by this equipment is 150Å / min,
A larger value was obtained than that obtained by radical beam CVD.

FIG. 2 shows a second embodiment of the present invention in which a magnet (5) for removing charged particles passing through the orifices (4) is arranged below each orifice (4). . According to this, when a large magnet is used to increase the central magnetic field, the size of the apparatus becomes large, and it is possible to eliminate the disadvantage that the magnetic field cannot be uniformly applied to each radical beam passing through each orifice. That is, by providing a magnet (5) at each orifice (4), a strong magnetic field can be applied to each beam and charged particles can be efficiently removed. The film formed by this example had less film quality defects than the film formed by the apparatus shown in FIG.

For the decomposition of the reaction gas in the decomposition chamber (1), it is possible to apply thermal decomposition as well as plasma discharge.

(Effects of the Invention) As described above, in the present invention, a vacuum decomposition chamber for decomposing a reaction gas and a vacuum film formation chamber in which a substrate is provided are connected through a large number of orifices, and The charged particles other than the radicals passing through the orifices are removed by the magnetic field that intersects the central axis of the orifices of the magnet provided between the orifices, and the light introduced through the transparent window of the film forming chamber Since the radicals are ionized and attached to the substrate, there are no charged particles that damage the substrate in the film formation chamber, and a highly reactive atmosphere of radicals is created, so that the film can be efficiently excited by light to form a film. The film formation speed is improved, radicals are evenly distributed from many orifices to a large number of locations on a large-area substrate, and uniform film formation is possible. Without film formation It has the effect of being practically applicable to the manufacture of semiconductor devices and the like.

[Brief description of drawings]

FIG. 1 is a cutaway side view of a first embodiment of the present invention, and FIG. 2 is a cutaway side view of a second embodiment of the present invention. (1) …… Decomposition chamber (2) …… Film forming chamber (3) …… Substrate (4) …… Orifice (5) …… Magnet (13) (14) (15) …… Light source

Continuation of the front page (56) References JP-A-59-188913 (JP, A) JP-A-59-144133 (JP, A) 1. Extended Abstracts 16th Int. Conf. SoL ID STATE DEVICES AND MATERIALS, 1984, P.I. L865-L867 2. JAPANESE JOURNAL OF APPLIED PHYSICS, 23 [11], (1984-11), P.P. 447-450

Claims (1)

[Claims] 1. A vacuum decomposition chamber in which a reaction gas is decomposed by plasma discharge or the like to generate radicals, and a vacuum film formation chamber in which a substrate on which a thin film is formed are provided are provided. The decomposition chamber and the film formation chamber are connected to each other through a large number of orifices to introduce the radicals into the film formation chamber, and charged particles other than the radicals passing through the orifice are provided between the substrate and the orifice in the film formation chamber. A magnet for forming a magnetic field that intersects the central axis of the orifice for removing the gas, and a surface reaction of the substrate in the film formation chamber from a light source provided outside the film formation chamber through a transparent window of the film formation chamber. Radiation beam light CV characterized by the introduction of light that excites light and excites radicals into ions
D device.