JPS63207121A - Method and apparatus for manufacturing thin film by photo-cvd - Google Patents

Abstract

PURPOSE:To prevent a window for introducing 'light' from clouding by holding a substrate at a temperature in which reactive gas is adhered in a liquid or solid state to the substrate under the condition in a reaction chamber, and holding it at a temperature lower than that of the 'window'. CONSTITUTION:The temperature of a substrate is held at relatively low temperature, generally below zero degree, reactive gas is thereby solidified or liquefied on the substrate. Simultaneously, the temperature of the substrate is held at lower temperature than that of a 'window'. Thus, high density reactive gas exists on the substrate, and low density reactive gas exists relatively on the 'window' 6 and in a reaction chamber 1. Accordingly, a 'light' is radiated in this state to conduct a photo-CVD. That is, the substrate is held at the temperature or lower in which the gas is adhered onto the substrate in a solid or liquid state in the chamber 1 and at lower temperature than that of the 'window' 6. It can prevent the inner surface of the 'window' 6 from clouding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a thin film by optical JCVD and an apparatus used therefor.

(Prior art) "Optical JCVD is a process using a reactive gas such as disilane (Si
zHa) gas or silane (SiHa) gas is introduced into a reaction chamber (vacuum chamber), and the substrate placed in the reaction chamber is irradiated with "light" through a "window" to convert the gas into, for example, the following formula: % formula %, a chemical reaction is caused by "light" and the reaction product is formed as a thin film on a substrate. The reaction product (SiHz)n decomposes and releases hydrogen by further receiving light or thermal energy, and ultimately becomes silicon (Si).

In this case, the "light" generally used is ultraviolet light, but it is not limited to this. It is possible to use up to electromagnetic waves (λ=too Å or more), and therefore, in this specification, "light" is used to mean electromagnetic waves.

A typical conventional apparatus used for optical CVD mainly consists of an airtight container (1a) for isolating the reaction chamber (1) from the surroundings, as shown for example in FIG.
A support stand (2) is fixed at the bottom of the reaction chamber (1),
A substrate holder (4) for mounting a substrate (S) is provided on the support stand (2). In addition, at the top of the reaction chamber (1) there is a "
A window (6) is provided, and the bottom of the reaction chamber (1) is provided with an inlet pipe (8) for introducing the reactive gas and an exhaust pipe (9) for discharging it.

The "window" (6) is located in a position where the "light" that passes through it can irradiate the substrate (S), and if the "light" is ultraviolet rays, the "window"
The material (6) -a is made of a material that transmits ultraviolet rays, such as quartz, calcium fluoride, and magnesium fluoride.

In some cases, the source of "light", e.g. an ultraviolet lamp, is
It may be built inside the reaction chamber (1), and in that case, the "window" can be said to insert the housing of the light source and also serve as the housing of the light source.

Therefore, in this specification, "window" is used in this sense.

In the reaction chamber (1), a substrate (
S) a reactive gas such as disilane (SigH*) gas is introduced such that a thin film of reaction products is deposited on the
Then, from the light source (7) through the “window” (6), the substrate (S
) is irradiated with "light", disilane gas decomposes, and a thin film of silicon hydride or silicon is deposited on the substrate depending on the energy of the "light".

[Problem that the invention seeks to solve]

However, since the "window" (6) is also exposed to the reactive gas, by irradiating the "light", the same kind of substance as on the substrate gradually accumulates on the window (6). ) was cloudy. When the "window" becomes cloudy, the intensity of light reaching the substrate (S) decreases, eventually making thin film production impossible. For example, in the case of silicon hydride, conventionally the maximum film thickness required at most 500 to 1000 people to continuously form the film.

In order to solve this problem, measures have been taken such as (1) applying oil to the "window" and (2) spraying inert gas on the "window", but these methods have prevented the "window" from fogging up. This could not be completely suppressed, and furthermore, a new problem occurred in that substances unrelated to film formation were introduced into the reaction vessel.

In addition, reaction products are generated or deposited in places other than the substrate in the same way as on the substrate, which causes flakes (
There was a problem that the thin film on the substrate could be damaged by the formation of fragments. Furthermore, in conventional photo-CVD, the concentration of the reactive gas is the same both on the substrate and in the optical path, so the "light" energy is already consumed in the photoreaction by the time it reaches the substrate.
There was a problem that the irradiation efficiency was low.

In addition, in conventional photo-CVD, the amount of reactive gas directly used to produce thin films is extremely small, approximately 1/100 to 1/10,000 of the amount of reactive gas introduced into the reaction chamber, resulting in +11 poor yields. (2) There is a problem in that large-capacity abatement treatment equipment is required to treat the unreacted reactive gas that is exhausted.

An object of the present invention is to provide a novel method for producing a thin film by optical J CVD and an optical J CVD apparatus used therein, which fundamentally solves the above-mentioned problems.

[Means for solving problems]

As a result of extensive research, the present inventors have determined that the temperature of the substrate is maintained at a relatively low temperature (generally negative), thereby causing the reactive gas to solidify or liquefy on the substrate while at the same time keeping the temperature of the substrate below the "window" temperature. By lowering the temperature, there is a high density of reactive gas (although not technically a gas) on the substrate, and a relatively low density of reactive gas on the "window" and inside the reaction chamber. Therefore, the inventors have discovered that the above-mentioned problems can be solved by irradiating light in this state and performing optical CVD, and have accomplished the present invention.

Therefore, the present invention first involves introducing a reactive gas into a reaction chamber, irradiating the substrate placed in the reaction chamber with "light" through a "window" to cause the gas to undergo a photochemical reaction, and thereby causing the reaction. In a method for producing a thin film by forming a thin film of a product on a substrate, the substrate is heated at a temperature below such that the gas adheres to the substrate in a solid or liquid phase in a reaction chamber. , and the method is characterized in that the temperature is maintained at a temperature lower than that of the "window".

In addition, the present invention provides, secondly, a temperature below which the reactive gas adheres to the substrate in a solid or liquid phase within the reaction chamber;
The ``Hikari J CVD'' is characterized by being equipped with a temperature control means (generally a cooling means) that maintains the temperature at a lower temperature than the ``window''.
equipment”.

[Effect]

The technical idea of the present invention is to maintain the substrate at a relatively low temperature, which is lower than the temperature of the "window", so that the reactive gas introduced into the reaction chamber is deposited on the substrate in a liquid or solid phase. , photoreact in that state.

The gas molecules of the reactive gas are at a lower temperature than the "window",
When it collides with a substrate kept at a relatively low temperature, energy is taken there and there is almost a 100% probability that it will adhere to the substrate, liquefy or solidify, and remain on the substrate. The number of molecules that fly away from the substrate in the gas phase again is determined by the vapor pressure depending on the temperature of the substrate, but is very small. Therefore, the reactive gas is present at a high concentration on the substrate and at a low concentration on the "window" and in the space of the reaction chamber. Although it is preferable to reduce the gas concentration in the reaction chamber to zero, it is practically impossible to reduce the gas concentration to zero because there is a very small vapor pressure. In any event, in accordance with the present invention, by providing a lower concentration on the substrate than in the "window" and reaction chamber spaces, various of the aforementioned problems are reduced or eliminated.

If the exposure is sufficient, the thickness of the thin film formed depends on the total number of molecules that remain on the substrate, so after creating a high vacuum in the reaction chamber, the substrate is cooled to a cryogenic temperature and the evacuation is stopped. If a reactive gas is then introduced, the total number of molecules will be approximately equal to the amount introduced.

On the other hand, if a reactive gas is introduced while exhausting, a certain percentage of the molecules will Adheres to the substrate.

Therefore, it is possible to form a thin film with a desired thickness by controlling the amount of gas introduced.

Note that even if the reactive gas is in a liquid or solid phase at room temperature, it can be used as long as it can be converted into a vapor phase by forced vaporization means such as heating or bubbling and introduced into the reaction chamber. For example, triethylaluminum, which is liquid at normal temperature and normal pressure, can also be used as the reactive gas. In this case, the substrate can be kept below about +30° C. (and the "window" can therefore be heated to a higher temperature).

Further, any reactive gas that does not cause a photochemical reaction in the gas phase but causes a photochemical reaction in the liquid or solid phase can be used.

The "light" does not have to be simply a spot light that uniformly irradiates the entire substrate.In order to directly produce a patterned thin film, the "light" does not have to be simply a spot light that uniformly irradiates the entire substrate.
In this case, an imaging optical system that forms a real image of a predetermined pattern on the substrate is used. Furthermore, even if the "light" is a spot light having an illumination area sufficiently smaller than the substrate and the spot light is moved during thin film manufacturing to draw a trajectory of a predetermined pattern, a patterned thin film can be directly manufactured. .

The optical CVD apparatus of the present invention mainly includes a reaction chamber, an airtight container for isolating the reaction chamber from the surroundings, a "window" for introducing the "light" into the reaction chamber, and a "window" for introducing the "light" into the reaction chamber. It consists of a substrate holder for holding the substrate in a position illuminated by the "light" and a cooling means for the substrate, but the light source may also be placed inside the reaction chamber (or a part of the window or All of them may be lenses.

In addition, by heating the inner walls and substrates of the reaction vessel in advance and evacuation, impurity gases and outgases contained or adsorbed in the inner walls and substrates are actively exhausted, thereby increasing the ultimate vacuum level. This may improve the cleanliness inside the reaction chamber. This heating is called baking, and the CVD apparatus of the present invention may be provided with heating means for baking.

After producing a thin film according to the present invention, the thin film may be heated to effect chemical or physical modification (eg, crystallization, progression of crystallization, modification of crystal structure, removal of internal strain, etc.). This is called annealing, and the CVD apparatus of the present invention may be provided with heating means for annealing.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

[Example 1] FIG. 1 is a conceptual diagram showing a vertical cross section of an optical J CVD apparatus according to this example.

This device consists of a reaction chamber (1), an airtight container (1a) for isolating the reaction chamber (1) from the surroundings, a support stand (2) provided at the bottom of the reaction chamber (1), and a support stand. (2) a substrate holder (4) detachably attached to the top; and an electric heater as a heating means (3) disposed inside the substrate holder (4) for heating the substrate (S). , support stand (2)
A cooling means (5) provided near the top of the reaction chamber (1) for cooling the substrate (S);
It mainly consists of a window (6), a reactive gas introduction vibrator (8) and an exhaust pipe (9) provided at the bottom of the reaction chamber (1).

In addition, in some cases, the support stand (2) and the substrate holder (4)
It doesn't have to be there.

A coolant such as liquid nitrogen or liquid helium is circulated in the cooling means (5), and the substrate (S) is cooled through the substrate holder (4).
) to below a predetermined temperature. The cooling means (5) does not cool anything other than the substrate (S) and the substrate holder (4), and the reaction chamber (1) and the "window" (6) are at room temperature. Also, instead of using a cooling means as shown in Figure 1, a cold
Cooling may be provided by a regenerative heat exchanger built into the reciprocating piston of the end-expansion engine.

Outside the "window" (6) there is a light source (7) consisting of an ultraviolet lamp, which may optionally form part of this device, through which the ultraviolet light illuminates the entire substrate (S). irradiate.

[Example 2] Using the apparatus of Example 1, the substrate holder (4) had a surface area of 1
After placing a clean substrate (S) consisting of a silicon wafer of 0.00 Cl11, the inside of the reaction chamber (1) was heated to 10-''tor
It was evacuated to a high vacuum of r or higher.

Thereafter, the substrate (S) was cooled to -140° C. by the cooling means (5) while continuing to exhaust the air.

On the other hand, the ultraviolet rays emitted by the light source (7) continue to irradiate the entire surface of the substrate (S) through the "window" (6), and in this state, high-purity disilane gas is irradiated at a rate of 0.05 cc per minute (0°C 1 atm conversion, below). A total of 6 cc was introduced at the same rate.

As a result, approximately 70% of the gas adhered to the substrate, resulting in a film thickness of approximately 3 μm.
A polysilane (low molecular weight (Silh)n) Fit film was formed. This is surprising considering that conventional photo-CVD can only produce a polysilane thin film with a maximum thickness of 0.1 μm.

Furthermore, when observed with the naked eye, no fogging was observed on the inner surface of the "window" (6).

[Example 3] Using the apparatus of Example 1, the substrate holder (4) had a surface area of 1
After placing a clean substrate (S) consisting of a 20-inch silicon wafer, the inside of the reaction chamber (1) was evacuated to a high vacuum of 10-'' torr or higher.

After that, the substrate (S) is heated to -130°C by the cooling means (5).
The reactor was cooled to a temperature of 100 cc, and then the exhaust was temporarily stopped, and 0.05 cc of high-purity disilane gas was introduced from the reactive gas inlet pipe (8). (Here, we stopped the exhaust after cooling, but if we did the opposite, the substrate would adsorb a large amount of impurities.) When the substrate was irradiated with ultraviolet rays, a film of amorphous hydrogen with a thickness of 200 nm was formed on the substrate. A silicon oxide film was formed.

However, when observed with the naked eye, no fogging was observed on the inner surface of the "window" (6).

[Embodiment 4] FIG. 2 is a conceptual diagram showing a vertical cross section of an optical JCVD apparatus according to this embodiment.

The configuration is almost the same as the device of Example 1, but it is thicker (the difference is that the "window" (6) is in the shape of a lens. Therefore, the ultraviolet rays from the light source (7) (S
) The irradiation area (spot) is sufficiently small compared to the entire surface. The light a (7) can be moved vertically and horizontally by a moving means (not shown), and the spot can draw an arbitrary linear locus on the surface of the substrate (S).

In addition, here, the substrate holder (4) to which the substrate (S) is attached closely is made to match the shape of the substrate (S), and the exposed part of the holder itself is minimized.
Since the entire holder (4) is cooled, the exposed portion is covered with a heat insulating material (10). Also, heating means (3) are not present here.

The "window" (6) is a lens, so the container (1a)
Ultraviolet light from an excimer laser, which is a light source (7) placed outside the substrate, passes through a "window" (6) and is focused on the substrate (S).

[Example 5] Using the apparatus of Example 4, the substrate holder (4) had a surface area of 1
After attaching a clean substrate (S) made of a 00d silicon wafer, the inside of the reaction chamber (1) was evacuated to a high vacuum of 10-1 torr or higher.

After that, the substrate (S) is heated to =150°C by the cooling means (5).
was cooled uniformly. On top of that, install the reactive gas introduction pipe (
High purity disilane gas (SizHJ) from Ice was introduced from 8). Approximately 70% of the introduced disilane molecules were condensed on the cooled substrate, and most of the remaining was exhausted.

Then, the ultraviolet light emitted by the light source (7) was irradiated onto the substrate (S) through the window J (6), and the light source was slowly moved in the vertical direction while irradiating it.

After that, when the cooling was stopped and the substrate temperature was returned to room temperature, the disilane that did not undergo a photoreaction was vaporized, and a linear silicon thin film was formed on the substrate following the trajectory of the irradiated light.

However, when observed with the naked eye, no fogging occurred on the inner surface of the "window" (6).

[Example 6] The apparatus is essentially the same as that of Example 1, except that a second heating means is added that can bake the inside of the reaction chamber (1).

[Example 7] Using the apparatus of Example 6, the substrate holder (4) had a surface area of 1
A substrate (S) consisting of a 00- silicon wafer was attached.

Then, thoroughly bake the reaction chamber (1) in advance and
"Evacuated to a high vacuum of -torr or higher.

After uniformly cooling the substrate (S) to -140°C by the cooling means (5), while irradiating the substrate (S) with ultraviolet rays, Ic
High purity disilane gas of e was introduced over time.

As a result, when the gas introduction was completed, an amorphous low-dimensional hydrogenated silicon thin film was formed on the substrate.

After this, cooling is stopped while continuing ultraviolet irradiation and exhaust, and conversely, the substrate temperature is gradually increased to 200% by heating means (3).
℃ and annealed at that temperature.

As a result, an amorphous high-dimensional hydrogenated silicon thin film having a thickness of approximately 1500 nm was obtained.

[Example 8] The basic configuration of the "optical JCVD apparatus" according to this example is as follows:
This device is the same as the device of Example 1, except that it includes an infrared lamp in addition to the ultraviolet lamp as the light source (7).

Further, in this device, a control means capable of controlling a minute flow rate is attached to the gas introduction pipe (8).

[Example 9] Using the apparatus of Example 8, after placing a substrate (S) made of a 2-inch silicon wafer on the substrate holder (4), the inside of the reaction chamber (1) was heated to a pressure of 10-” torr or more. Evacuated to high vacuum.

After that, the substrate (S) is heated to -140°C by the cooling means (5).
was cooled uniformly. On top of that, install the reactive gas introduction pipe (
8), 0.3 x 10-'cc of high-purity disilane gas was introduced.

As a result, it seems that the reactive gas condensed on the substrate to form a liquid or solid disilane monolayer film.

After irradiating the entire surface of the group+ffE(S) with ultraviolet rays through the "window" (6) to form a silicon thin film,
While cooling continued, annealing was performed by irradiating infrared rays instead of ultraviolet rays. (In this case, infrared rays were irradiated while cooling was continued, but the next process started up faster that way.) After that, the process was cooled again in the same way, and the introduction of disilane, ultraviolet ray irradiation, and infrared ray irradiation were repeated 70 times. So, about 1
A crystalline Si film with a thickness of 0.00 mm was manufactured.

[Example 10] Using the apparatus of Example 8, the total surface area of the substrate holder was 1OO
- After placing a substrate made of a flat silicon wafer, the reaction chamber was evacuated to a high vacuum of 10-'' torr or higher.

Next, while cooling the substrate to -150°C, 0.03 cc of high-purity disilane gas is introduced into the reaction chamber, and the substrate is irradiated with ultraviolet rays to cause a photoreaction. The outermost surface was heated to produce an amorphous hydrogenated silicon thin film.

After that, the substrate was cooled again to -150°C, and 0.03cc
By introducing high-purity disilane gas and 0.08 cc of ammonia gas, irradiating them with ultraviolet rays to cause a photoreaction, and irradiating them with infrared rays along the way, an amorphous hydrogenated nitrided silicon thin film with a wide optical band gap is created. was formed.

Thereafter, the formation of a silicon hydride thin film and a silicon hydride nitride film were alternately repeated in the same way, and one period of 40
A film with a thickness of 400 mm formed by laminating a total of 100 cycles of alternating sets of human hydrogenated silicon thin films and hydrogenated silicon nitride thin films.
0 amorphous superlattice films were manufactured.

[Example 11] Using the apparatus of Example 8, the total surface area of the substrate holder was 200
- After placing a substrate made of a flat (100)-plane GaAs wafer, the inside of the reaction chamber was evacuated to a high vacuum of 10-' torr or higher.

In the first step, after cooling the substrate to -100°C, 0.03 mg of forcibly gasified trimethyl gallium was introduced into the reaction chamber, irradiated with ultraviolet rays to cause a photoreaction, and then added to the ultraviolet rays. The outermost surface of the substrate was heated by also irradiating it with infrared rays.

Next, in the second step, after cooling the substrate to -100°C, the forcibly gasified trimethylarsine was
amg was introduced, irradiated with ultraviolet rays to cause a photoreaction, and then irradiated with infrared rays in addition to ultraviolet rays.

The first and second steps were alternately repeated 100 times to obtain a GaAs epitaxial crystal thin film with a thickness of 290 mm.

[Embodiment 12] FIG. 4 is a conceptual diagram showing a vertical cross section of an optical JCVD apparatus according to this embodiment.

This device consists of a reaction chamber (1), an airtight container (1a) for isolating the reaction chamber (1) from the surroundings, a support stand (2) provided at the bottom of the reaction chamber (1), and a support stand. (2) A substrate holder (4) removably attached to the top and a support stand (2)
), three "windows" (6) provided at the top of the reaction chamber (1), and three "windows" (6) provided at the bottom of the reaction chamber (1): It mainly consists of a gas introduction pipe (8) and an exhaust pipe (9). "window"
(6) is made of quartz or magnesium fluoride.

Outside the three "windows" (6) there is a vacuum ultraviolet light source (7), for example a deuterium lamp, a low-pressure mercury lamp, etc., which may optionally form part of the device, a heating light source (11), for example an infrared lamp. , and an auxiliary light source (12), such as a high-pressure mercury lamp, are provided, and "light" illuminates the entire substrate (S) through a "window" (6).

(Example 13) Using the apparatus of Example 12, a clean substrate (S) made of a silicon wafer with a surface area of 100 - is placed in the substrate holder (4).
After the reaction chamber (1) was placed in a high vacuum of 10-9 torr or more, the auxiliary light fA (12) was turned on during this period to clean the substrate surface.

Thereafter, the substrate (S) was cooled to −150° C. by the cooling means (5) while continuing to exhaust the air.

On the other hand, the vacuum ultraviolet light emitted by the light source (7) is transmitted through the "window" (6).
The entire surface of the substrate (S) was continuously irradiated through the irradiation chamber, and in this state, 0.006 cc of high-purity disilane gas was introduced.

As a result, a polysilane'fN film with a thickness of about 30% was formed, with about 50% of the gas adhering to the substrate and the rest being exhausted.

Thereafter, the temperature of the outermost surface of the substrate was raised for a short time by irradiation with an infrared lamp of a heating light source (11), and at the same time vacuum ultraviolet rays were irradiated. Cooling continued so that the substrate was cooled again to -150° C. within 30 seconds after the end of the infrared lamp irradiation.

Therefore, 0.006 cc of high-purity disilane gas was introduced again, and the process of irradiating with vacuum ultraviolet rays and then simultaneously irradiating with vacuum ultraviolet rays and infrared rays was repeated 300 times to form about 800 crystalline silicon thin films.

Furthermore, when observed with the naked eye, no fogging was observed on the inner surface of the "window" (6).

[Example 14] Using the apparatus of Example 12, a clean substrate (S) made of a silicon wafer with a surface area of 200 d was placed in the substrate holder (4).
After placing the reaction chamber (1), the interior of the reaction chamber (1) was evacuated to a high vacuum of 10-9 torr or more, and during this time the auxiliary light source (12) was turned on to clean the substrate surface.

Thereafter, the substrate (S) was cooled to -140° C. by the cooling means (5) while continuing to exhaust the air.

On the other hand, the vacuum ultraviolet light emitted by the light source (7) is transmitted through the "window" (6).
The entire surface of the substrate (S) was continuously irradiated through the irradiation chamber, and in this state, 0.1 cc of high-purity disilane gas was introduced over 2 minutes.

As a result, about 50% of the gas adhered to the substrate and the rest was evacuated), forming an amorphous hydrogenated silicon thin film.

Next, the cooling was stopped and the infrared lamp of the heating light source (11) was irradiated to heat the silicon hydride thin film, thereby decomposing and removing hydrogen in the silicon hydride thin film and improving the film quality.

Thereafter, the infrared ray irradiation was stopped, the substrate was again cooled to -80°C, and this time 0.07 cc of tungsten hexafluoride was introduced over 2 minutes. As a result, about 50% of the gas adhered to the substrate and the rest was exhausted), forming a tungsten thin film.

Next, the quality of the tungsten thin film was improved by stopping the cooling and heating it by irradiating it with an infrared lamp of the heating light source (11).

By repeating the above steps of forming a hydrogenated silicon thin film, improving the film quality, and forming a tungsten thin film, and improving the film quality 100 times, the X! ! i
! A reflective multilayer film was formed.

〔Effect of the invention〕

As described above, according to the present invention, the substrate is maintained at a temperature below the temperature at which the reactive gas adheres to the substrate in a liquid or solid phase under the conditions in the reaction chamber, and at a temperature lower than the temperature of the "window". Because the substrate is held, the gas concentration inside the window and reaction chamber is relatively low compared to the substrate surface, and the exposure reaction is performed in a situation where there are very few reactive molecules in the gas phase, so "light" is introduced. fog is less likely to form on the windows.

In addition, the problem of damage to the thin film due to flakes and the problem of low irradiation efficiency because the "light" energy is already consumed in the photoreaction before reaching the substrate can be solved. In addition, most of the reactive gas introduced into the reaction chamber can be used for thin film production. This solves the problem of requiring .

This method is free from the limitations of film formation that were considered to be the limitations of conventional optical CVO, and has the effect of allowing the formation of thick thin films.

Furthermore, according to the present invention, the reactive gas is liquefied or solidified (condensed) on the substrate in a thickness of one molecule by cooling.
This has the effect of producing thin films with a thickness of one atomic unit, and by devising film formation conditions, it can also be applied to amorphous superlattices, crystalline superlattices, and epitaxial growth.

Moreover, even if it is deposited (agglomerated) on a substrate in a supported phase or a liquid phase, there is an effect that a local temperature increase due to light irradiation causes a local gas phase reaction to occur in a space extremely close to the substrate surface.

Furthermore, since it can be evacuated to a high vacuum even after adhesion (coagulation), it has the effect of forming a film in a cleaner environment compared to conventional optical CVD equipment.

Furthermore, since the "windows" were freed from fogging, inert gas spraying, which had previously been taken as a countermeasure against "windows" fogging,
There is no need to bring in substances unrelated to the reaction, such as applying oil, into the container, and there is no need to wipe or etch the ``window,'' which has the effect of allowing the shape of the ``window'' to be complicated and improved.

According to Example 5.6, the reactive gas (not exactly a gas) that aggregated in the unexposed areas is vaporized and exhausted by increasing the temperature after film formation, so etching, etc. This has the effect that there is no need to take the trouble to remove it.

Further, according to Example 7.9.10.13.14, annealing can be incorporated into film formation, so the temperature conditions of film quality can be controlled, and Example 13.14
According to , by irradiating with auxiliary light, it is possible to clean the substrate surface and improve the film quality.

In addition, with a device that can provide heat by lamp irradiation as in Example 12, it is possible to heat the vicinity of the outermost layer without stopping cooling, so fine-grained temperature control can be achieved for each single layer or several layers. This has the effect of quickly improving film quality through control.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing a vertical cross section of an "optical" CVD apparatus according to a first embodiment of the present invention. FIG. 2 is a conceptual diagram showing a vertical cross section of an "optical" CVD apparatus according to a fourth embodiment of the present invention. FIG. 3 is a conceptual diagram showing a vertical cross section of a conventional "optical" CVD apparatus. FIG. 4 is a conceptual diagram showing a vertical cross section of an "optical" CVD apparatus according to Embodiment 12 of the present invention. be. [Explanation of symbols of main parts] S...Substrate 1...Reaction chamber 1a...Airtight container 2...Support stand 3...Heating means 4...Substrate holder 5...Temperature adjustment means Cooling means 6 as an example... "window" 7... Light source 8... Gas introduction pipe 8... Exhaust pipe 10... Heat insulating material 11... Heating means for annealing 12... Auxiliary light source

Claims (1)

[Claims] 1. A reactive gas is introduced into a reaction chamber, and a substrate placed in the reaction chamber is irradiated with "light" through a "window" to cause the gas to undergo a photochemical reaction, thereby producing the reaction product. In a method for manufacturing a thin film by forming a thin film on a substrate, the substrate is heated to a temperature below such that the gas adheres to the substrate in a solid or liquid phase in the reaction chamber, and and the above “
A method characterized by maintaining the temperature at a temperature lower than that of the window. 2. The method according to claim 1, wherein the "light" is ultraviolet light, visible light, or infrared light. 3. The method of claim 1, wherein the "light" forms a predetermined pattern of illuminated areas on the substrate. 4. Claim 1, wherein the "light" has an illumination area on the substrate that is smaller than the substrate, and the "light" moves on the substrate to draw a trajectory in a predetermined pattern during manufacturing. Method described. 5. Claim 1, wherein the concentration of the gas in the reaction chamber is such that a thin film is not substantially formed in parts other than the substrate even when the gas is exposed to "light". Method described. 6. Even if the gas is in a liquid or solid phase at room temperature, it is converted into a vapor phase by forced vaporization means such as heating or bubbling,
The method according to claim 1, characterized in that the method can be introduced into the reaction chamber. 7. The method according to claim 1, wherein the gas causes a photochemical reaction in a liquid phase or a solid phase even though it does not cause a photochemical reaction in a gas phase. 8. The "optical" CVD apparatus is characterized by being equipped with a temperature control means that maintains the reactive gas at a temperature below the temperature at which it solidifies or liquefies on the substrate and lower than the temperature of the "window". A device that does this. 9. The apparatus includes at least a reaction chamber, an airtight container for isolating the reaction chamber from the surroundings, an exhaust pipe for evacuating the inside of the reaction chamber, and a gas introduction pipe for introducing a reactive gas into the reaction chamber. a pipe, a "window" for introducing "light" into the reaction chamber, a substrate holder for holding a substrate at a position in the reaction chamber illuminated by the "light", and the temperature adjustment means. An "optical" CVD apparatus according to claim 8, characterized in that it comprises: 10. The device according to claim 8, characterized in that a light source for the "light" is built-in, and the "window" also serves as a housing for the light source. 11. The device according to claim 9, wherein part or all of the "window" is a lens. 12. The device according to claim 8, wherein the "light" is ultraviolet light, visible light, or infrared light. 13. The apparatus of claim 8, wherein the "light" forms a predetermined pattern of illuminated areas on the substrate. 14. Claim 8, wherein the "light" has an illumination area on the substrate that is smaller than the substrate, and during manufacturing, the "light" moves on the substrate to draw a trajectory in a predetermined pattern.
Apparatus described in section. 15. Claim 8, wherein the concentration of the gas in the reaction chamber is such that a thin film is not substantially formed in parts other than the substrate even when the gas is exposed to "light". The device described. 16. The apparatus according to claim 8, further comprising heating means for heating the substrate. 17. The apparatus according to claim 16, wherein the heating means is a heating means for annealing the produced thin film. 18. The apparatus according to claim 17, wherein the heating means is an electric heater, an infrared lamp, or a microwave heating device. 19. The apparatus according to claim 8, further comprising heating means for baking the inside of the reaction chamber.