JPH036017A - Optical cvd apparatus - Google Patents

Abstract

PURPOSE:To elongate a life of a light source and to stabilize a quantity of light by a method wherein a shutter mechanism which advances and retreats a shutter is installed between an irradiation window of a reaction chamber and the light source. CONSTITUTION:A reaction chamber 12 and a light-source chamber 13 are installed, by using an irradiation window 11 as a boundary, so as to be adjacent to the upper side and the lower side; a heater table 14 as a heating means is installed in parallel with the irradiation window 11 at the inside of the reaction chamber 12. In addition, a plurality of light sources 15 composed of discharge lamps are installed at equal intervals in parallel with the irradiation window 11 at the inside of the light-source chamber 13; an evacuation means 16 and a gas supply means 17 are installed at the reaction chamber 12. A shutter mechanism 21 which advances and retreats a shutter is installed between the irradiation window 11 of the reaction chamber 12 and the light sources 15. When the light sources 15 are turned on and the shutter is opened in a state that a quantity of light of the light sources 15 has been stabilized, a film formation operation is started. When the shutter is closed, the film formation operation is finished. Thereby, a life of the light sources 15 can be elongated, and the quantity of light can be stabilized.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is directed to a photo-CVD method that can produce amorphous silicon thin film transistors and the like using photochemical reactions.
(Chemical Vapor Deposition) equipment.

(Prior Art) As shown in FIG. 7, a conventional photo-CVD apparatus has a reaction chamber 2 and a light source chamber 3 adjacent to each other on the lower and upper sides with a horizontal irradiation window 1 through which light passes as a boundary. A heater table 4 is provided inside the reaction chamber 2 parallel to the irradiation window 1, and a plurality of light sources 5 are provided inside the light source chamber 3 parallel to the irradiation window 1 at equal intervals. Some are equipped with a supply means 7.

In this apparatus, a substrate 8 is held and heated on a heater table 4, the inside of a reaction chamber 2 is brought into a vacuum state by an exhaust means 6, and a film-forming material is supplied to the inside of the reaction chamber 2 by a gas supply means 7 instead. The substrate 8 is irradiated with light from the light source 5 through the irradiation window 1, and the gas is decomposed directly or indirectly by the light energy, thereby producing a film on the surface of the substrate 8. When the light source 5 is turned on, film formation is started, and when the light source 5 is turned off, the film formation is completed.

(Problems to be Solved by the Invention) In the conventional optical CVD apparatus described above, film formation is started when the light source 5 is turned on, and film formation is completed when the light source 5 is turned off.

Therefore, the light source 5 must be blinked every time a film is formed, which shortens the life of the discharge lamp of the light source 5. Moreover, it takes a long time to stabilize the amount of light after the light source 5 is turned on. There is a problem in that it takes time to form layers, and furthermore, the amount of light during each film formation is not stable, resulting in variations in the thickness of the formed thin film.

The present invention was made in view of the above points, and the present invention has been made in view of the above points.
The purpose of this is to prolong the life of the light source and stabilize the amount of light.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a reaction chamber in which an object to be deposited is placed and an irradiation window through which light passes through the object, and the object inside the reaction chamber. a heating means for heating the inside of the reaction chamber; an evacuation means for bringing the inside of the reaction chamber into a vacuum state; a gas supply means for supplying a gas serving as a film forming material into the inside of the reaction chamber; This is an optical CVD apparatus equipped with a light source that irradiates light onto an object inside, and a shutter mechanism that moves the shutter forward and backward between the irradiation window of the reaction chamber and the light source.

In particular, in the invention according to claim 2, the shutter is made of a sheet that moves along an endless path including between the irradiation window of the reaction chamber and the light source.

Further, particularly, in the invention according to claim 3, the shutter is composed of a plurality of shutter plates that move forward and backward between the irradiation window of the reaction chamber and the light source.

(Function) The photoCVD apparatus of the present invention starts film formation by opening the shutter with the light source turned on and the light intensity of the light source stabilized, and finishes film formation by closing the shutter. It is something.

In particular, in the invention of claim 2, by using a sheet for the shutter, the stiffness of the shutter can be minimized. By arranging them in the same direction, it is possible to prevent the archetype distribution from becoming uneven due to opening and closing of the shutter.

Moreover, especially in the invention of claim 3, the installation space for the shutter can be reduced.

(Example) An example of the optical CVD apparatus of the present invention will be described with reference to the drawings.

1 and 2 show a first embodiment.

As shown in FIG. 1, like the conventional device shown in FIG. 7, the photo-CVD apparatus of this embodiment has a reaction chamber 12 and a light source chamber 13 separated by a horizontal irradiation window 11 through which light passes. A heater table 14 as a heating means is provided adjacent to the lower and upper sides of the reaction chamber 12 and parallel to the irradiation window 11, and a plurality of light sources 15 made of discharge lamps are installed inside the light source chamber 13 and connected to the irradiation window. 11 and at equal intervals in parallel with reaction chamber 1.
2 is provided with an exhaust means 16 and a gas supply means 17.

The apparatus of this embodiment, like the conventional apparatus, has a substrate 18 as an object to be deposited on the heater table 14.
is held and heated, the inside of the reaction chamber 12 is brought into a vacuum state by the exhaust means 16, and instead, the gas supply means 17 supplies St, 4, H2, N, which are the film forming materials, to the inside of the reaction chamber 12.
A gas selected from Hs, PL, etc. is supplied, and the light source 15 irradiates the substrate 18 with light through the irradiation window 11.
Decomposes gas directly or indirectly using light energy,
This causes a film to be formed on the surface of the substrate 18.

In this optical CVD apparatus, from the light source 15 to the substrate 1.
A shutter mechanism 21 is provided to control the light irradiated onto 8 .

As shown in FIG. 2, this shutter mechanism 21 surrounds the light source 15 in the light source chamber 13 with four rollers 22, and these four rollers 22 have flexibility and light shielding properties.
An endless sheet 23 made of stainless steel with a thickness of
The sheet 23 is provided with an opening 25 corresponding to the irradiation window 11. One roller 22 is driven in one direction by a motor 24.

In this shutter mechanism 21, by rotating the roller 22 in one direction with the motor 24, the opening 25 of the sheet 23 moves from the upper side of the light source 15 to the lower side via one side, and then , moves from the lower side of the light source 15 to the upper side via the other side and circulates, so the light source 15 is circulated through the opening 25 of the sheet 23 using the sheet 23 as a shutter.
and the irradiation window 11 on the lower side thereof can be opened and closed, and the movement direction of the sheet 23 during the opening operation and the closing operation is the same.

Therefore, before starting film formation, the light source 15 is turned on with the space between the light source 15 and the irradiation window 11 closed by the sheet 23, and the light amount of the light source 15 is sufficiently stabilized.
Film formation is started by moving the opening 25 of the sheet 23 between the light source 15 and the irradiation window 11 to open the space between the light source 15 and the irradiation window 11, and after a predetermined time has elapsed, the sheet 23
By moving the opening 25 from between the light source 15 and the irradiation window 11 to another position and closing the space between the light source 15 and the irradiation window 11, the film formation can be completed. The amount of light from the light source 15 remains stable until the end, and the time from the start to the end of film formation can be shortened.

Then, with the light source 15 still lit,
After replacing the board 18 and completing preparations, replace the sheet 23 again.
By moving the opening 25 between the light source 15 and the irradiation window 11, it is possible to start film formation on the next substrate 18, so when repeating film formation on multiple substrates 18, it is possible to start and finish film formation. There is no need to turn on and off the light source 15 each time, and the life of the light source 15 made of a discharge lamp can be extended.

Furthermore, when film formation is repeated on a plurality of substrates 18, the amount of light from the light source 15 is stable each time, so that the film thickness is
It does not change from time to time.

Since the movement direction of the sheet 23 is the same during the opening operation and the closing operation, the total light reception time is the same for any part of the substrate 18, even if there is a time difference, and the substrate 18
Since the amount of light is equal in all parts, the film thickness distribution becomes uniform.

Furthermore, since the sheet 23 is used for the shutter, the distance between the light source 15 and the substrate 18 does not become long, and no loss of light quantity occurs.

3 to 6 show a second embodiment.

This embodiment differs from the first embodiment described above only in the shutter mechanism, but the structure of other parts is the same.
The same parts as those in the first embodiment are given the same reference numerals, and the explanation will be omitted, and the explanation will focus on the different parts.

The shutter mechanism 31 of this embodiment is provided with a rail 32 on the side of the irradiation window 11 on the light source chamber 13 side, and this rail 32 has a plurality of light-shielding blocks that form a shutter.
, a shutter plate 33 with a thickness of 5 cylinders is attached to each guide 3.
4, the plurality of shutter plates 33 are formed so as to be partially or entirely stackable, and are connected to an endless wire 36 extending along the rail 32 via a pair of pulleys 35. The uppermost shutter plate 33 is fixed, and one pulley 35 is driven by a pulse motor 37 in both forward and reverse directions.

This shutter mechanism 31 is operated by a pulse motor 37.
By rotating the boot IJ35 in the forward or reverse direction, the uppermost shutter plate 33 moves from one end of the irradiation window 11 to the other end, or from the other end to the one end,
At this time, the lower shutter plate 33 follows the uppermost shutter plate 33, and can open and close between the light source 15 and the irradiation window 11 below it.

Therefore, prior to the start of film formation, as shown in FIGS. 3 and 4, a plurality of shutter plates 33 are deployed between the light source 15 and the irradiation window 11. is closed, the light source 15 is turned on, and when the light intensity of the light source 15 is sufficiently stable, as shown in FIGS. By laminating the light source 15 and opening the space between the light source 15 and the irradiation window 11,
After starting film formation and elapse of a predetermined time, as shown in FIGS. 3 and 4, a plurality of shutter plates 33 are connected to a light source 15
Since the film formation can be completed by expanding the film between the light source 15 and the irradiation window 11 and closing the space between the light source 15 and the irradiation window 11, the amount of light from the light source 15 is always stable from the start to the end of the film formation. state, and the time from the start to the end of film formation can be shortened.

Then, with the light source 15 still lit,
When the substrate 18 is replaced and preparations are made, film formation on the next substrate 18 can be started by stacking the plurality of shutter plates 33 on one end side of the irradiation window 11 again. When film formation is repeated, it becomes unnecessary to turn on and off the light source 15 each time film formation starts and ends, and the life of the light source 15 made of a discharge lamp can be extended.

Furthermore, when film formation is repeated on a plurality of substrates 18, the amount of light from the light source 15 is stable each time, so that the film thickness is
It does not change from time to time.

Generally, the light irradiation time and the thickness of the thin film produced are proportional to each other, so when using a shutter that moves back and forth like this example, the movement of the shutter when it opens and closes. When the direction is reversed, if the shutter movement speed is slow, the difference in light irradiation time depending on the position on the substrate 18 becomes large, resulting in uneven film thickness distribution, and furthermore, the thickness of the thin film to be formed becomes uneven. The thinner the layer, the greater the effect.

Now, considering the deposition of amorphous silicon thin film, considering that the variation in film thickness distribution without using a shutter was ±20 people, the influence when using a shutter is estimated to be less than ±10 Å. For this purpose, the total time required for opening and closing the shutter must be 5 seconds or less.

For this reason, this device adopts a blind system in which the shutter is configured by a plurality of shutter plates 33, and is driven at high speed by a pulse motor 37 to eliminate the adverse effects of the reciprocating shutter.
The installation space for the shutter could be reduced.

Furthermore, in order to prevent the shutter from increasing the distance between the light source 15 and the substrate 18 and causing loss of light quantity, this device uses a shutter plate 33 with a thickness of 0.5 mm, so that the entire shutter is The thickness of the lens was set to 5 mm to prevent loss of light quantity.

〔Effect of the invention〕

As described above, according to the photoCVD apparatus of the present invention, film formation is started by turning on the light source and opening the shutter while the light intensity of the light source is stable, and film formation is started by closing the shutter. Since the film is finished, the light intensity of the light source is always stable from the start to the end of film formation, which shortens the time from the start to the end of film formation. Replace the board in the same state, and when you are ready, open the shutter again.
Since deposition can be started on the next substrate, there is no need to turn on and off the light source each time the deposition starts and ends, extending the life of the light source, and repeating deposition on multiple substrates. In this case, the amount of light from the light source is stable each time, so the film thickness does not change from substrate to substrate.

In particular, in the invention of claim 2, by using a sheet for the shutter, the thickness of the shutter can be minimized to prevent loss of light amount due to an increase in the distance between the light source and the substrate. By making the direction in which the sheet moves in the same direction during operation and the direction in which the sheet moves during closing operation, any part of the board can be moved in the same direction, even if there is a time lag.
The total light reception time is equal, and the amount of light is equal on all parts of the substrate, so the film thickness distribution becomes uniform.

Moreover, especially in the invention of claim 3, the installation space for the shutter can be narrowed.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of a photo-CVD apparatus corresponding to claims 1 and 2 of the present invention, and FIG. 1 is a structural diagram thereof;
FIG. 2 is a perspective view of the main part thereof, and FIGS. 3 to 6 are optical CVDs corresponding to claims 1 and 3 of the present invention.
This is the second embodiment of the device, and FIG. 3 is a structural diagram of the device in its shutter closed state, FIG. 4 is a perspective view of its main parts, FIG. 5 is a structural diagram of its shutter open state, and FIG. 6 is its main components. FIG. 7 is a structural diagram of a conventional optical CVD apparatus. 11. Irradiation window, 12. Reaction chamber, 14. Heater table as heating means, 15. Light source, 16. Exhaust means, 17. Gas supply means, 18. Substrate as target object, 21. - Shutter mechanism, 23... Sheet as a shutter, 31... Shutter mechanism, 33... Shutter board that constitutes the shutter.

Claims (3)

[Claims] (1) A reaction chamber in which an object to be formed into a film is arranged and having an irradiation window through which light passes through the object, a heating means for heating the object inside the reaction chamber, and the reaction chamber. an evacuation means for bringing the inside of the reaction chamber into a vacuum state; a gas supply means for supplying a gas serving as a film forming material into the inside of the reaction chamber; and a light source that irradiates light onto an object inside the reaction chamber through the irradiation window. A photo-CVD apparatus comprising: a photo-CVD apparatus comprising: a shutter mechanism for moving a shutter forward and backward between the irradiation window of the reaction chamber and the light source;
VD device. (2) The photo-CVD apparatus according to claim 1, wherein the shutter is comprised of a sheet that moves along an endless path including between the irradiation window of the reaction chamber and the light source. (3) The photoCVD apparatus according to claim 1, wherein the shutter comprises a plurality of shutter plates that move forward and backward between the irradiation window of the reaction chamber and the light source.