JPH01241818A - Device for forming light excitation film - Google Patents

Abstract

PURPOSE:To prevent a film from accumulating on a light-transmission window by cooling the window using a cooling gas flowing through. CONSTITUTION:A light-transmission window 22 is provided between a film forming room 11 and a light source housing room 19. It also serves to separate these rooms. It is formed by a quart sufficiently permeable to light of the ultraviolet region, and is fixed on a holder 23. A hole 24 is opened inside the light- transmission window 22 so as to flow a cooling gas, inside of which is cooled by flowing a gas which does not absorb ultraviolet light such as N2 or He so that the light-transmission window 22 is not heated. The cooling gas is introduced from the outside through an open hole 25 connected to holder 23. The light-transmission window 22 and the holder 23 are connected with a seal member. As a result of this, the film forming room 11 and the light source housing room 19 are separated pressure-wise, and the cooling gas is arranged not to be leaked to the outside.

Description

Detailed Description of the Invention [Purpose of Takuma] (Field of Industrial Application) This Takuma is concerned with a photo-CVD device that forms a thin film on a substrate by using photoexcitation (H-chemical reaction), and in particular, it is concerned with a photo-CVD device that forms a thin film on a substrate using a light excitation reaction. The present invention relates to a photo-CVD device Jjl+ which has an improved cooling method.

(Prior Art) In recent years, as semiconductor integrated circuits have progressed, there has been a demand for smaller device sizes and higher integration.To achieve this, the optical excitation process, which is a low-cycle and damage-free semiconductor manufacturing process, has been developed. Attention has been paid. As a device using a photoexcitation process, a photo-CVD device is in practical use. This device consists of a vacuum container in which the wafer to be processed is placed, a means for introducing a raw material gas into the container, a means for irradiating light onto the wafer through a light transmission window provided in a part of the d chamber, etc. . Then, by irradiation with ultraviolet light, etc., 1
By exciting the wafer surface, CVD particles are deposited on the wafer.

By the way, in the optical CVD apparatus, CV
While depositing pattern D, a thin film is also deposited on the light transmission window. This is because the temperature of the light transmitting window also increases and the film deposition reaction is promoted. When a thin film is deposited on the light-transmitting window, the amount of light incident on the wafer is reduced, and the film formation rate is significantly reduced. For this reason, methods have been considered to minimize the amount of film deposited on the light transmission window. One such method is to apply Fomblin oil, which has a low vapor pressure, in advance to one light transmitting window. This has the disadvantage that the phonoprine oil evaporates during the period in which the phonoprine oil plays the role of preventing film deposition on the light transmitting window and is trapped as an impurity in the deposited film on the wafer. As a method, for example, N! is placed between the reaction gas and the light transmission window so that the reaction gas does not come into direct contact with the light transmission window. There is a way to flow an inert gas such as gas. However, this 17% O reaction gas and N! Since it is almost impossible to prevent the gases from actually mixing, gradual film deposition on the light-transmitting window results in incomplete dilution due to simultaneous clouding of the reactant gas%N and gasG. This has a negative effect on the rate of waste deposition on the wafer and the uniformity of the film quality. Another method is to cool the window by blowing N, gas, etc. onto the surface of the light-transmitting window from the light source side, but in most cases, the light-transmitting window and the light source are placed close to each other. If N or gas is blown from the periphery, the gas will diffuse to the periphery, and the effect of cooling the light transmission window will be considerably reduced.

(Problem to be Solved by the Invention) Conventionally, in a photo-CVD device (IIF), the I1W pattern deposited on the five-element transmission window causes a decrease in the amount of incident light, leading to a significant decrease in the film formation rate. Alternatively, methods have been taken to prevent film deposition on the light transmitting window as described above.
In either case, the effects were insufficient or other negative effects occurred.

The present invention has been developed in consideration of the above circumstances, and is not only effective in preventing film deposition on the light transmission window, which causes a decrease in film formation speed, but also has an adverse effect on the film deposited on the wafer. 6 [Structure of the Invention] (Means for Solving the Problems) The gist of the present invention is to supply a cooling gas through a light transmission window The objective is to cool the window by flowing it and prevent film deposition on the light-transmitting window.

That is, the present invention provides a former CVD apparatus for forming a pattern on a substrate to be processed by photoexcited decomposition of a source gas, a film forming chamber in which the substrate is collected and used for film formation, and a film forming chamber for forming the film. a light transmitting window provided in a part of the chamber, a means for introducing source gas into the film forming chamber, and a means provided outside the film forming chamber,
The substrate holder in the film forming chamber includes a light source that irradiates the source through the light transmission window, and is provided with means for flowing cooling gas into the light transmission window.

(Function) According to the present invention, the light transmitting window can be cooled more effectively than fogging by flowing cooling gas into the light transmitting window. As a result, the film is not deposited on the light transmitting window, and stable film formation can be performed without causing a decrease in the amount of incident light.

Furthermore, since the cooling gas flows through the light transmitting window, there are no adverse effects such as contamination of impurities into the grown film from adhesion prevention oil or dilution of the reaction gas by the cooling gas, which is the case in the prior art.

(Example) The following five details of the present invention will be explained with reference to the illustrated embodiments. FIG. 1 is a schematic configuration diagram schematically showing the main part of an optical CVD apparatus according to an embodiment of the present invention.

In the figure, reference numeral 11 denotes a film forming chamber, and in this film forming chamber 11, a substrate holder 13 and a sample stage 14 are housed, on which a plate 12 to be processed, such as a Si wafer or a glass substrate, is mounted. The substrate holder 3 is attached to the sample stage 14 through the chuck 151.
f is installed. Inside the sample stage 14, there is a substrate 12.
A heater 16 is provided for heating. In addition, monosilane C3i is supplied from the gas supply section 17 into the formation chamber 11.
A raw material gas such as H4) is introduced, and the gas in the film forming chamber 11 is exhausted by an exhaust pump 18.

On the other hand, a light source accommodating chamber 19 is connected to the lower part of the side forming chamber 11, and a light source zO consisting of, for example, a low-pressure mercury lamp that emits ultraviolet light is housed in this light source accommodating chamber 19. A reflector plate 21 is disposed below the light source 20. The inside of the light source housing chamber 9 is kept in a gas atmosphere or a vacuum atmosphere that does not absorb ultraviolet light. A light-transmitting window 22 is provided between the compartment and the holder 23 to separate the compartment. The light transmitting window 22 has a hollow hole 24 through which cooling gas can flow.
Alternatively, the light transmitting window 22 is cooled by flowing a gas such as He that does not absorb ultraviolet light so as not to increase its temperature. During cooling, gas is introduced from the outside through a hole 25 connected to the holder 23 and opened.

Although the light transmission window 22 and the holder 23 are not shown, they are connected by a sealing member, and through this the model armature chamber 1 and the light source chamber I9 are pressure-separated, and the cooling gas is released from the outside. I'm doing my best to keep it from leaking.

FIG. 2 is a plan view of the light transmitting window viewed from above. The holes for flowing the cooling gas into the light transmission window 22 are shown in the same figure (a).
), one hole may be formed to cover the entire light transmitting window 22, as shown by the shaded area 24 in FIG. , a plurality of holes may be made in the light transmission window 22 and gas may be allowed to flow therethrough during cooling.

With such a structure in which gas flows through the light transmission window 22 during cooling, the five-source transmission window 22 is cooled very effectively, so that the 771] heat of the substrate 12 to be processed and the secondary heat from the light source 20 are removed. It is possible to suppress the increase in the intensity of the light transmitting window 22, which is normally caused by heat radiation, and as a result of this, the light transmitting window 22 is free from deposits of marks, without causing a decrease in the amount of incident light.
A stable film can be formed on the substrate to be processed 12i. In addition, it is no longer necessary to apply oil to the light-transmitting window 22 to prevent adhesion, unlike in the past, so there is no need for impurities to be mixed into the grown film from this oil. In the conventional method, the reaction gas is diluted with an inert gas, which causes no change in the growth rate or adverse effects on the film quality. Improvement and stability ('r11.'i can be measured.

FIG. 3 is a schematic view schematically showing a second embodiment of the present invention, and only the light transmitting window 22 and holder 23 shown in FIG. 1 are shown. Incidentally, the same parts as those in the first diagram are given the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the previously described embodiments in that the light transmitting window 22 is easily attached and detached. That is, in the previous embodiment, the light transmitting window 22 was fixed to the holder 23 via a sealing member, but in this embodiment, the light transmitting window 22 is fixed to the holder 23 from the bottom through the O-link seals 26-I to 26. -4
Push up the pillars 27-E and 2 etc. through the 1st column and bring them into close contact. During cooling, gas flows through the holder 23 and the light transmission window 22 (holes 25 + 24':
During cooling, gas will not flow into the model room, since it is designed to flow through the model and is separated from the outside by an O-ring seal. With such a structure, the light transmitting window 220 can be attached and detached individually, and can be taken out, cleaned, or replaced as required.

Even with this structure, the same effect as in the previous embodiment can be obtained. Note that in this embodiment, the light transmitting window 22 is a holder 23.
The bottom number indicates 't&.

It is also possible to provide the reverse (this upper part E).

FIG. 4 is a schematic diagram showing a third embodiment of the present invention, and like the broom in FIG. 3, only the '#S transmission window 22 and a portion of the holder are blanked out. Note that the same parts as in FIGS. 1 and 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

This embodiment differs from the first and second embodiments described above in that the light transmitting window is composed of two sheets. In other words, in the previous embodiment, there is a hole in the light transmitting window 22. 24 and let the cooling gas flow through it, but in this example, 24 is opened.
It is composed of two light transmitting windows 22-1 and 22-2, and a cooling gas is allowed to flow through a space 28 between them. Light transmission window 22-1.

2 are 0syg seals 26-1~
By contacting the holder 23 through the holder 27-4 and pressing it from above and below with the supports 27-1 to 27-4, etc., the cooling gas can flow in this internal holder in a sealed state. In addition, in this embodiment, no machining is required to make a hole in the light transmission window 22-1.2, and attachment and detachment of the light transmission window 22-1.2 is easy.
It can be taken out, cleaned or replaced as needed.

Even with such a structure, the same effects as in the previous embodiment can be obtained.

Note that the present invention is not limited to the embodiments described above. For example, the substrate may be transported into the model chamber by a cassette-type tray that integrates the light-transmitting window and the substrate to be processed. Further, as a light transmission window cooling mechanism, a mechanism such as water cooling of the holder to prevent fogging, cooling gas blowing from the light source chamber side, etc. may be added. Also, the cooling gas is N.

The material is not limited to He, but any material that can sufficiently transmit the excitation wavelength light of the source gas may be used. Furthermore, the light source is not limited to a low-pressure mercury lamp, but may also be a deuterium lamp, an excimer laser, or the like. Further, the raw material gas and the pattern to be formed are not limited as long as they can be used for photo-CVD. Furthermore, although the present invention has been described using an example of film formation by photoexcitation, it is also possible to apply the same method to an etching device using photoexcitation or a combination thereof. In addition, various modifications can be made without departing from the essence of the present glossy hair.

〔Effect of the invention〕

As detailed above, according to the present invention, since the cooling gas is flowed inside the light transmitting window, the cooling effect of the light transmitting window is high, and this t''L prevents gas from accumulating on the light transmitting window. It is possible to form a stable film on the substrate to be processed without reducing the amount of incident light by E%.
R. A film grown from oil that was generated by applying oil to prevent false adhesion to the transparent window or flowing an inert gas between the light transmitting window and the reaction gas D. There is also an adverse effect on film quality, such as dilution due to inertness, and it is possible to improve film quality and stability.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram schematically showing an optical CVD enclosure according to a first embodiment of the present invention, FIG. 2 is a plan view of the light transmission window used in the above device, viewed from above, and FIG. 3 , @4 Figures 2 and 4 of the present invention, respectively. FIG. 7 is a schematic configuration diagram showing the configuration of main parts of a third embodiment. 11... Film formation chamber, 12... Substrate to be processed, 13...
・Substrate holder, 14... Sample stage, 15... Chuck, 16... Heater, 17... Gas supply section, 18
...Vacuum pump, 19...Light source housing section, 20...
Light source, 21...Reflector plate% 22...Light transmission window, 23
...Holder, 24゜25...Gas circulation hole for disposal,
26...0 ring seal, 27... strut. Agent Patent Attorney Noriyuki Ken Yudo Matsuyama Mitsuyuki ([No+Higashi (V+1)

Claims (4)

[Claims] (1) a film formation chamber that accommodates a substrate to be processed and is used for film formation; a light introduction window provided in a part of the film formation chamber; and means for introducing source gas into the film formation chamber; At least a light source provided outside the film forming chamber and irradiating the substrate to be processed in the film forming chamber with light through the light introduction window,
A photoexcited film forming apparatus for forming a film on the substrate to be processed by photoexcited decomposition of the source gas, wherein the light introduction window is configured to allow a cooling gas to flow inside. (2) The photoexcited film forming apparatus according to claim 1, wherein the cooling gas is supplied through the inside of the holder that supports the light transmission window, and has a structure in which it does not flow into at least the film forming chamber. . (3) The photoexcited film forming apparatus according to claim 1 or 2, wherein the light transmitting window has a structure that allows it to be easily attached to and detached from the holder. (4) The photoexcited film forming apparatus according to claim 1, 2 or 3, wherein the light introduction window is composed of two parallel flat plates, and the cooling gas is allowed to flow between them.