JP2000119856A - Formation of film by cvd method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the phenomenon that the intermediate decomposed reaction product of a vaporized precursory adheres to a wall in a carrying stage on the way and, particularly to the periphery of a blow-off part to disturb film formation. SOLUTION: Relating to this film forming method by a CVD method, in a CVD method in which a precursory for film formation is evaporated and is carried in the vaporized state together with a carrier gas, and gas is blown against a substrate from a blow-off part 2 to form a film composed of the decomposed reaction product on the substrate, the precursory is evaporated at a temp. giving the saturated vapor pressure of >=0.1 KPa and is carried together with the carrier gas without dropping the temp., the front stand of the blow-off part is provided with a filtering means 6, and, the temp. on the space from the filtering means to the tip of the blow-off part is held to the one higher than the above temp. by >=10 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a film by a CVD method and an apparatus therefor, and more particularly to a method of depositing and depositing intermediate decomposition and reaction products of a precursor vapor around a blowing section.
The present invention relates to a method for forming a film and a device for preventing the film from being hindered from being formed on a substrate.

[0002]

2. Description of the Related Art In the CVD method, when a precursor for forming a film is a liquid or a solid, the precursor is heated to a temperature at which a predetermined vapor pressure is obtained, and the vapor is inert gas or air. And the like as a carrier gas, guided to the vicinity of the substrate surface heated to a desired temperature, sprayed from the gas (steam) blowing portion to the substrate surface, and decomposed, oxidized, nitrided, carbonized, and a complex reaction of the two occurs on the substrate surface. , An oxide film, a nitride film and the like. In order to induce the decomposition and the reaction, various energy supply means such as plasma, flame projection, and infrared heating may be employed in addition to heating the substrate itself.

[0003] The vapor pressure of the precursor is closely related to the film formation rate, that is, the productivity, and a high vapor pressure is required to speed up the film formation. For this purpose, an evaporator or a carrier gas is used. In both cases, it is necessary to raise the temperature.
However, when the temperature is increased, decomposition and reaction are promoted, and decomposition and reaction products are deposited and adhere to the wall of the transport pipe, the wall of the plenum and members around the blowout section, and the flow of gas is hindered. When the decomposition products adhere to the periphery of the portion, the gas is blown to the substrate in a non-uniform manner, so that the uniformity of the coating is impaired and the film thickness tends to be non-uniform. Conversely, lower temperatures, and thus lower vapor pressures of the precursors, will hinder productivity.

[0004] The vaporized precursor is generally an organometallic compound or a metal halide (mainly chloride).
However, at a temperature near the surface of the substrate at the blowout portion (or in some cases using plasma, flame projection, or the like as described above), it becomes a final decomposition / reaction product and forms a film. As described above, the intermediate decomposition / reaction products are deposited on the walls in the transportation process in the middle and especially around the blow-out portion, and adhere to the portions. The intermediate decomposition / reaction product may still be in the form of an organometallic compound or a metal halide, or may be in the form of a tar, which is further polymerized.
The method and apparatus of the present invention are effective in suppressing such intermediate decomposition and precipitation of reaction products.

[0005]

According to the present invention, a precursor for forming a film is vaporized, transported together with a carrier gas in a vaporized state, and the gas is blown onto a substrate from a blow-out portion to form the precursor on the substrate. In the CVD method for forming a film composed of decomposition and reaction products, the precursor is evaporated at a temperature exhibiting a saturated vapor pressure of 0.1 KPa or more, and transported together with a carrier gas without lowering the temperature. And a film forming method by a CVD method in which a temperature between the filtration means and the tip of the blowing section is maintained higher than the temperature by 10 ° C. or more.

In the above, the precursor for forming a film is
It is preferred to evaporate at a temperature that exhibits a saturated vapor pressure of less than 10 KPa.

Further, it is preferable to form a film continuously on a heated glass strip which is being continuously drawn from a forming area in a sheet glass manufacturing process.

The present invention also provides a film forming precursor,
An evaporator that heats and vaporizes to a vapor pressure of 0.1 KPa or more, a transport pipe having a heating maintaining means for transporting the vapor together with a carrier gas at the vaporization temperature, and a blowing unit that blows the gas through a plenum onto a substrate surface And a heating control means for disposing a filter at a location from the plenum toward the blowing section, and maintaining the temperature at a temperature higher by 10 ° C. or more than the temperature between the filter installation point and the tip of the blowing section. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a precursor for forming a film is evaporated, transported together with a carrier gas in a vaporized state, and the gas is blown onto a substrate from a blowing portion to decompose the precursor on the substrate. In the CVD method for forming a film made of a reaction product, the precursor is evaporated at a temperature at which the precursor exhibits a saturated vapor pressure of 0.1 KPa or more, more preferably at a temperature at which a saturated vapor pressure of 1 KPa or more is exhibited. At a temperature lower than 0.1 KPa, the amount of vaporization is small, and the deposition rate is significantly impaired. The precursor vaporized at a temperature exhibiting a vapor pressure of 0.1 KPa or more causes decomposition / reaction, albeit small,
In addition, the higher the vapor pressure, that is, the higher the temperature,
Although the reaction product is likely to be generated, the precipitation is suppressed as much as possible by taking the above-mentioned solution.

[0010] The amount of the intermediate decomposition / reaction products of the precursor adhered to the transportation process and the like when vaporized at a low temperature varies depending on the kind of the precursor and the form of the compound. Tar-like substances adhere, and as the temperature increases, the amount of the adhered substance increases, and a non-tacky substance tends to adhere gradually.

It is preferable that the precursor for film formation is evaporated at a temperature exhibiting a saturated vapor pressure of less than 10 KPa. Intermediate decomposition of the precursor and precipitation of the reaction product become remarkable in the transport path, the plenum wall, and the like, and it becomes difficult to form a film in a relatively short time.

By the way, in the CVD method, it is well known that a precursor for forming a film is vaporized, the vapor is transported together with a carrier gas at the vaporization temperature, and further discharged through a plenum from the tip of a blowing portion. It is common general technical knowledge (for example, Japanese Patent Application Laid-Open No. 2-167842) to equip the blowing section with a uniforming means such as a buffer plate in order to blow out the gas uniformly and to guide the gas to the tip (slit).

[0013] In the present invention, a heating means for arranging a filtering means, for example, a filter, at a position from the plenum toward the blowing section, and maintaining the temperature higher than the temperature by 10 ° C. or more between the filter installation point and the tip of the blowing section. Means, for example, a conductive wire for heating (there may be a case in which a double wall for circulating a heating fluid is provided), air cooling for overheating suppression, a water cooling pipe, and the like.

That is, no matter how the vaporized precursor is maintained and transported in the above-mentioned vaporization temperature range, decomposition and reaction occur gradually, and intermediate decomposition and reaction products are generated in the gas flow. When the intermediate decomposition / aggregation of the reaction product progresses to form coarse particles, the particles adhere to the walls of the transport path, the wall of the plenum, the wall of the outlet, and the outlet slit.

In the arrangement of the filtering means (filter), the intermediate decomposition / reaction products of the gas are deposited on the wall of the blowing section or on the blowing slit at the tip, and the gas flow becomes uneven and the coating becomes uneven. It is intended to prevent the discharge slit from becoming impossible due to partial blockage or the like.

Further, by keeping the temperature (wall temperature) between the filtration means and the tip of the blowing section higher than the vaporization temperature by 10 ° C. or more, preferably by 20 ° C. or more, the precursor material near the blowing section is maintained. Even if the intermediate decomposition / reaction product adheres in the form of a sticky substance or tar, it promotes the further decomposition / reaction and turns it into a non-sticky powder. Has a tendency to be re-vaporized to suppress the adhesion and deposition of the intermediate decomposition / reaction product. However, the temperature should be kept below a temperature at which a saturated vapor pressure of 10 KPa is exhibited at the time of heating the precursor, and if it exceeds the temperature, the decomposition and reaction become rather remarkable, and the non-sticky decomposition and reaction product Tends to increase.

The film-forming precursors capable of exhibiting the above effects of the present invention include cobalt (III) acetylacetonate, indium acetylacetonate, zirconium (IV) acetylacetonate, copper (II) acetylacetonate, and chromium acetylacetonate. Acetonate, ferrocene (reaction accelerating substance: oxygen), alkoxysilane and / or siloxanes (reaction accelerating substance: phosphoric acid ester <phosphite> and / or ozone), alkoxy titanium chloride (reaction accelerating substance: phosphoric acid ester <phosphorous acid Ester> and / or ozone and / or water).

[0018]

The present invention will be described below in detail with reference to specific examples. FIG. 1 is a schematic partial sectional view of a CVD apparatus according to the present invention.

Example 1 5 g / min of cobalt (III) acetylacetonate (Co (acac) ₃ ) was vaporized at 210 ° C. with bubbling gas, ie, 10 NL / min of nitrogen gas.
The carrier was transported in the transport pipe 8, and 70 NL / min of dry air as a carrier gas was fed into the transport pipe 8 via the branch pipe 9 and transported together. The transport pipe 8 is the Co (acac) ₃ vapor,
A heater (not shown) is provided so as to maintain a mixed gas G composed of nitrogen gas and dry air at 210 ° C. The temperature at which the vapor pressure of Co (acac) ₃ is 0.1 KPa is 110 ° C.
The temperature indicating a vapor pressure of 10 KPa is 270 ° C.
Exhibits a vapor pressure of 3 KPa.

On the other hand, a float plate glass 1 of 30 × 30 cm (5 mm thickness) was used as a substrate, heated to 600 ° C. in advance, and transferred at a speed of 1 m / min by a transfer means, for example, a roller conveyor 7. The gas G was sprayed from the transport pipe 8 through the plenum 3 to the surface of the float glass sheet 1 from the blowout section 2.

The plenum 3 has a width 30 in the width direction of the glass plate 1.
cm, a room section having a slit (internal slit) 4 at the lower bottom, an inner heater 10 is provided around the room, and the gas G is maintained at 210 ° C.

Similarly, the width direction of the blowing section 2 is substantially equal to the width of the glass plate 1 of 30 cm, and the tip (lower end) of the blowing section 2 has a gap of 1.5 mm.
To form a blowing slit 2 ′ whose longitudinal length is substantially equal to the width of the glass plate 30 cm, and discharges gas G from the blowing slit 2 ′ to the surface of the glass plate 1 being transferred. The gas G was decomposed and reacted by the heat of the glass plate 1 to form a coating of cobalt oxide which is a metal oxide in this embodiment.

In the blowout section 2, two buffer plates 5 as shown in FIG. 1 are arranged in order to blow the gas G evenly across the width of the glass plate 1. The arrangement of the buffer plate is a common technical knowledge in the technical field as described above.

Further, in the present embodiment, an opening of 1 to several tens μm (for example, 1 μm) is formed on the internal slit 4 at the plenum outlet with a heat-resistant and non-reactive substance (for example, made of ethylene tetrafluoride).
The filter 6 of □) is provided. Between the filter 6 and the outlet slit 2 'at the tip of the outlet, an internal heater 11 for heating and an air cooling pipe 11' for preventing overheating, for example, overheating from the glass plate 1, are arranged to adjust the heating. During this time, the temperature was maintained at 230 ° C., which was 20 ° C. higher than the aforementioned temperature of 210 ° C.

As described above, when the filter 6 is disposed, the intermediate decomposition / reaction product of the gas G is deposited on the blowout portion 2, especially the blowout slit 2 ', so that the discharge gas flow becomes uneven and the coating film becomes uneven. It is intended to prevent the film from becoming uniform and, furthermore, the blowing slit 2 'from being unable to form a film due to partial blockage or the like. In the filter 6, the intermediate decomposition / reaction products are gradually added.
For example, the plenum may be opened and closed, and the upper cover 3 ′ may be opened and the filter 6 may be replaced with a new one.

Further, by maintaining the temperature between the filter and the tip of the blowing section at 10 ° C. or more higher than the temperature up to the plenum, the intermediate decomposition / reaction product of the precursor is reduced to a sticky substance near the blowing section. Even if it adheres in the form of tar or tar, further decomposition / reaction is promoted, it becomes powder without tackiness, and it is re-vaporized to suppress the adhesion and deposition of the intermediate decomposition / reaction product. be able to.

The gas after spraying is discharged as an exhaust gas WG by an appropriate exhaust means, in the drawing, a plenum 3 and an exhaust duct 12 arranged before and after the blow-out portion 2.
In this state, the glass plates were transported one after another at intervals of 10 minutes, and the film quality of the formed glass plate 1 was inspected and compared. As a result, the cobalt oxide film had a uniform thickness of 40 nm and uniform coating. The visible light transmittance was in the range of 39.7 to 40.0%, and it was confirmed that the film was formed stably.

After the test, the plenum 3 and the blowing section 2 were disassembled and inspected and observed. As a result, a brown decomposition product had adhered to the filter 6, but no adhering substance was observed in the internal slit 4. In the vicinity of the blowing section 2, almost no deposits were observed. When the blowing slit 2 ′ was wiped with white paper, it was found that fine black powder was slightly adhered.

[Comparative Example 1] A film formation test was performed on the float plate glass 1 under the same conditions as in Example 1 except that the filter 6 was removed and the same precursor as in Example 1 was used.

The visible light transmittance of the first glass plate is 39.8%.
In contrast, the visible light transmittance of the fifth glass plate is 4
3.6%, the 10th sheet was 62.3%, showing that the coating was gradually thinning. From the 6th sheet, countless vertical streaks were visible along the direction of movement of the glass plate. It was confirmed that the vertical streaks became clear.

After the test, when the plenum 3 and the blowing section 2 were disassembled, it was confirmed that a brown decomposition product (intermediate product) was remarkably adhered to the entrance of the internal slit 4 and was partially blocked. .

[Comparative Example 2] A float plate glass 1 was formed under the same conditions as in Example 1 except that the temperature between the internal slit 4 and the blowing slit 2 'was maintained at 210 ° C. Filmed.

Slight vertical streaks were observed from the second glass plate, and a clear streak pattern was observed on the fifth glass plate, and stable film formation was impossible. Plenum 3 after the test
When the blowout portion 2 was disassembled, a brown decomposition product was adhered in the form of an uneven mass around the blowout slit 2 ′, and the streak pattern and the position of the unevenness of the adhered material coincided.

Comparative Examples 3 and 4 The same apparatus as in Example 1 was used, except that Co (acac) ₃ was heated at 110 ° C. (0.1 K
pa) to vaporize (Comparative Example 3), and Co (acac) ₃ as another example.
Was vaporized at 300 ° C. (40 KPa) (Comparative Example 4), and was maintained at that temperature up to the tip of the blowing section (blowing filter).

In Comparative Example 3, the amount of vaporization was insufficient, and
The film thickness is not enough, and the film thickness is about 7-10 μm,
I didn't get anything. In Comparative Example 4, many Co (a
cac) _Three Is disassembled in the transportation process and adheres to the wall.
Clear film formation unevenness was observed on the glass plate of No. 5,
Blow-off slit is closed on glass plate of No.
It became.

[Embodiment 2] In the same apparatus as in Embodiment 1, copper
(II) 3 g / min of acetylacetonate (Cu (acac) ₂ )
It is vaporized at 260 ° C. with nitrogen gas at NL / min and transported by the transport pipe 8 while maintaining at 260 ° C. Further, 30 NL / min of dry air is fed into the transport pipe 8 via the branch pipe, transported, and implemented. Example 1
Similarly, the surface of the float glass sheet 1 heated and transferred was sprayed from the blowing section 2. The temperature was kept at 280 ° C. from the filter 6 to the outlet slit 2 ′ at the tip of the outlet.

The temperature at which the vapor pressure of Cu (acac) ₂ exhibits a vapor pressure of 0.1 KPa is 150 ° C., and the temperature at which the vapor pressure of Cu (acac) ₂ exhibits a vapor pressure of 10 KPa is
At 280 ° C, the vapor pressure is 4 KPa at 260 ° C.

In the same manner as in Example 1, ten glass sheets were successively transferred, and the quality of the formed glass sheets was inspected and compared. As a result, a copper oxide film having a uniform thickness of 50 nm and a uniform thickness was obtained. And the visible light transmittance is in the range of 51.3 to 51.7%,
It was confirmed that the film was formed stably.

After the test, the plenum 3 and the blowing section 2 were disassembled and inspected and observed. As a result, a brown decomposition product was attached to the filter 6, but no attached substance was observed in the internal slit 4. Near the blowing slit 2 ', almost no deposits were observed.

[0040]

According to the present invention, it is possible to suppress the adhesion and deposition of the intermediate decomposition and reaction products of the precursor in the vicinity of the blowing section, and to form a stable film.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Float sheet glass 2 Blow-out part 2 'Blow-off slit 3 Plenum 4 Internal slit 5 Buffer plate 6 Filter 7 Roller conveyor 10 Internal heater 11 Internal heater 11' Air cooling tube

Claims (4)

[Claims] 1. A precursor for film formation is evaporated, transported together with a carrier gas in a vaporized state, and the gas is blown onto a substrate from a blowing portion to decompose and decompose the precursor on the substrate.
In the CVD method for forming a film made of a reaction product, the precursor is evaporated at a temperature exhibiting a saturated vapor pressure of 0.1 KPa or more, transported together with a carrier gas without lowering the temperature, and filtered at a stage before the blowing section. CV, wherein the temperature between the filtration means and the tip of the outlet is maintained at least 10 ° C. higher than the temperature.
Method D for forming a film. 2. The method according to claim 1, wherein the precursor for forming the film is evaporated at a temperature exhibiting a saturated vapor pressure of less than 10 KPa. 3. The CVD method according to claim 1, wherein a film is continuously formed on a heated glass strip being continuously drawn from a forming area in a sheet glass manufacturing process.
Film formation method by the method. 4. An evaporator for heating and vaporizing a precursor for forming a film to have a vapor pressure of 0.1 KPa or more, and a transport pipe having a heating maintaining means for transporting the vapor together with a carrier gas at the vaporization temperature. A blower that blows the gas to the substrate surface via the plenum, and a filter disposed at a location from the plenum toward the blower, and maintained at a temperature of 10 ° C. or more higher than the above temperature between the filter installation point and the tip of the blower. A film forming apparatus based on a film forming method by a CVD method, comprising: