JPH08125185A - Method and system for fabricating thin film transistor - Google Patents

Abstract

PURPOSE: To fabricate a high performance thin film transistor stably on a glass substrate and a plastic substrate by introducing an inert gas heated to a predetermined temperature into a space set with a substrate prior to formation of a thin film constituting a thin film transistor thereby removing impurities from the surface of the substrate. CONSTITUTION: N2 gas heated by means of a heater 113 is blown onto a glass substrate 103. Adsorbed water molecules of several molecular layers, which can not be desorbed under ordinary vacuum state, can be desorbed effectively from the surface through interaction between the heated gas and the adsorbed molecule. Since a high quality thin film can be formed, with high adhesion, even onto a glass or plastic substrate, a thin film transistor having higher performance and stabilized characteristics can be fabricated with high yield.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor manufacturing method and a manufacturing apparatus, and more particularly to a manufacturing method and a manufacturing apparatus for stably forming a thin film transistor having high characteristics on a glass substrate or a plastic substrate.

[0002]

2. Related Art A thin film transistor is widely used as a switching element of a liquid crystal display device or the like, and a glass substrate is usually used as its substrate.

In the process of studying stabilization of thin film transistor characteristics and improvement of yield, the present inventor produced a thin film transistor on a glass substrate by a conventional method, as compared with a case where it was produced on an oxide film of a silicon wafer, for example. We have found that the characteristics are not stable and the yield is reduced due to dielectric breakdown.

Therefore, as a result of diligent examination of the cause, in the case of a glass substrate, it is impossible to perform high-temperature treatment like a silicon substrate, so that water and organic substances of several molecular layers remain on the glass substrate, and these are gradually removed during thin film formation. It has been found that the characteristics of the release thin film are degraded, and as a result, the stability of the thin film transistor performance and the yield are reduced.

Therefore, when a glass substrate is used, a method and apparatus capable of completely removing impurities adsorbed on the glass substrate at a low temperature are required to manufacture a thin film transistor having higher performance and stable characteristics with a high yield.

On the other hand, since the glass substrate is easily damaged by the impact when dropped, it has a drawback that it is difficult to use in a portable device or the like. There is also a demand for further weight reduction. Therefore, studies have been made to use a plastic substrate as the substrate of the thin film transistor, but in the case of a plastic substrate, it is necessary to perform the above impurity removal treatment at a lower temperature.

[0007]

In view of the above situation, the present invention provides a thin film transistor manufacturing method and a manufacturing apparatus capable of stably manufacturing a high performance thin film transistor on a glass substrate and a plastic substrate. To aim.

[0008]

A thin film transistor manufacturing method of the present invention is a thin film transistor manufacturing method for manufacturing a thin film transistor on a glass substrate or a plastic substrate, wherein the substrate is installed before forming a thin film constituting the thin film transistor. An inert gas heated to a predetermined temperature is introduced into the space and the substrate and the inert gas are brought into contact with each other to remove impurities on the surface of the substrate.

Another thin film transistor manufacturing method of the present invention is a thin film transistor manufacturing method for manufacturing a thin film transistor on a glass substrate or a plastic substrate.
Before forming a thin film forming a thin film transistor, an inert gas is introduced into a space in which the substrate is placed in a state where the substrate is heated to a predetermined temperature, and the substrate and the inert gas are brought into contact with each other to form a substrate surface. It is characterized by removing the impurities.

It is preferable to repeat the operation of introducing the inert gas until a predetermined pressure is reached, and then rapidly exhausting to a predetermined pressure at an exhaust rate of 300 (l / sec) or more. Further, the impurity concentration in the inert gas is preferably 1 ppb or less.

The thin film transistor manufacturing method of the present invention is characterized in that ozone or a mixed gas containing ozone is used in place of the inert gas.

Further, before removing the impurities by the inert gas, ozone or a mixed gas containing ozone is introduced into the space and brought into contact with the substrate, and then a vacuum state is set.

The thin film transistor manufacturing apparatus of the present invention has at least one vacuum processing chamber for removing impurities on the surface of a glass substrate or a plastic substrate, and at least one film forming chamber for forming a thin film forming a thin film transistor on the substrate. In the thin film transistor manufacturing apparatus having, the vacuum processing chamber comprises means for heating and blowing out an inert gas or / and ozone, exhaust means, and means for carrying in / out a substrate between the film forming chamber. It is characterized by having. Further, it is preferable that the vacuum processing chamber is provided with a heating means for heating the substrate.

The exhaust means preferably has an exhaust speed of 300 (l / sec) or more. Further, the vacuum processing chamber preferably has a chromium oxide passivation film formed on the inner surface.

The present invention is particularly effective when the impurities are water or organic impurities.

[0016]

[Function] By blowing a heated high-purity inert gas onto a glass substrate placed in a vacuum and bringing the glass substrate surface into contact with the heating gas, the interaction between the heating gas and the adsorbed molecules causes a normal vacuum state. Adsorbed water molecules of several molecular layers, which cannot be completely desorbed by itself, can be effectively desorbed from the surface.

Further, the glass substrate is installed in the vacuum chamber
Vacuum, then blow heated inert gas to vacuum
When the pressure in the room reaches a certain level, exhaust it and evacuate it again.
Repeat this operation (this operation will be
), The effect of desorption of water is further improved. Especially,
When exhausting, the exhaust speed is rapid at 300 (l / sec) or more.
If it is exhausted, the efficiency of removing adsorbed water is further improved.
You. The reason for this is currently unclear, but high pressure
From 10 to vacuum at a high speed, especially 10 ^-2To
In a viscous flow region above rr, high-speed gas on the substrate surface
A flow is generated to remove adsorbed impurity molecules.
Conceivable.

Further, instead of using the heated gas, by heating the substrate itself without heating the gas,
Similar water desorption effect can be obtained. Furthermore, heating gas and substrate heating may be used in combination. Furthermore, the gas may be sprayed onto the substrate, or the spraying position may be moved.

The heating temperature of the gas or the substrate can be appropriately determined in consideration of the number of purges, because the same effect can be obtained even at a low temperature by increasing the number of batch purges. Further, since the substrate is distorted due to the size and material of the substrate, the substrate temperature is limited by this.
For example, in the case of a glass substrate, 300 ° C. or less is preferable for a 10 cm square, and 250 ° C. or less for a 45 × 35 cm square. Further, in the case of a plastic substrate, for example, in the case of polycarbonate, it is preferable to set the temperature to 100 ° C. or lower at which no distortion occurs.

The inert gas of the present invention is, for example, N ₂ , Ar.
Etc. are preferably used, and the impurity concentration in the inert gas is 1 p
The purity is preferably pm or less, and more preferably 1 ppbb or less. However, depending on the volume of the vacuum processing chamber, the heating temperature, the type of substrate, the purpose of use, etc., an inert gas having a purity of less than this may be used. Needless to say.

When an organic substance other than water is adsorbed on the surface of the substrate, the organic substance is partially removed by the treatment with the above-mentioned inert gas, but in order to completely remove it, it is preferable to perform the treatment with ozone gas. In this case, the organic matter on the surface can be completely removed by leaving the substrate in an ozone atmosphere having a predetermined concentration and a predetermined pressure for a predetermined time and then reducing the pressure. Also,
Batch purging may be performed as described above. Ozone is
It is obtained by introducing O ₂ gas (or O ₂ gas containing about 10% N ₂ etc.) into the ozone generator, and the concentration is the pressure in the vacuum processing chamber, the substrate temperature, the standing time, the substrate material. It is appropriately determined by the above.

The above-mentioned polycarbonate is preferably used as the plastic substrate of the present invention, but an inorganic coating may be applied to the surface.

Next, an example of the vacuum processing chamber of the thin film transistor manufacturing apparatus of the present invention is shown in FIG.

In FIG. 1, 101 is a vacuum processing chamber, which is connected to a load lock chamber and a sputtering device (not shown) via gate valves 102 and 102 ', respectively, and a substrate is transferred between the chambers by a transfer mechanism (not shown). It has a structure that can carry in and out.

The vacuum processing chamber 101 is connected to an exhaust means (for example, a turbo molecular pump 104 and a roughing pump 105) via a valve 107 and vacuum exhaust passages 108 and 108 ', and the inside is 10 ^-8 to 10 ^-10. Can be kept at Torr. The vacuum processing chamber 101 and the vacuum exhaust passage 10
For 8, 108 ', it is preferable to use, for example, SUS316L in which the inner surface is mirror-polished and then a passivation film of a Cr ₂ O ₃ film is formed. As a result, it is possible to obtain a surface having very little adsorption of the released gas and moisture.

A substrate 103 and a substrate support 109 are provided with a heating means (heater) 110 therein. 11
Reference numeral 1 denotes a means for blowing an inert gas onto the substrate 103, which is connected to the gas supply passage 112. The gas supply passage 112 has a heater 113 for heating the inert gas to a predetermined temperature, a mass flow controller 114, a valve 115.
Is installed.

On the other hand, 119 is a means for blowing ozone gas onto the glass substrate, which is connected to an ozone generator (not shown) via a gas supply passage 120. The gas supply passage 1
20 includes a mass flow controller 121 and a valve 12.
2 are installed.

To remove adsorbed impurities on the substrate using the apparatus shown in FIG. 1, the following process is performed, for example.

First, the gate valve 102 is opened, the glass substrate is loaded from the load lock chamber onto the support 109 and installed, and the inside of the vacuum processing chamber 101 is decompressed. Then, the valve 107 is closed and the valve 115 is opened, and the inert gas heated by the heater 112 is supplied from the gas blowing means 111 onto the glass substrate 103.

While monitoring the pressure in the vacuum processing chamber 101 with the pressure gauge 116, a predetermined value (1.5 kg / cm ²
The inert gas is continuously supplied until the temperature becomes equal to or less than that), then the valve 115 is closed and the valve 107 is opened.
The inside of the vacuum processing chamber 101 is rapidly evacuated by the vacuum pump 4 and the roughing pump 105.

By repeating the above-described operation (batch purge) several times, it becomes possible to remove the adsorbed impurities on the substrate surface.

[0032]

The present invention will be described in more detail with reference to the following examples, but it goes without saying that the present invention is not limited to these examples.

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIG.

First, the N heated by the heater 113
When the ₂ gas was blown on the glass substrate 103 was examined temperature relationship of the N ₂ gas temperature and the glass substrate 103 in the N ₂ gas outlet 111. The results are shown in Figure 2. Figure 2
As can be seen, the temperature of the glass substrate 103 is increased by increasing the temperature of the N ₂ gas.

From the above experimental results, in this embodiment, the temperature of the N ₂ gas at the blowout port 111 was set to 300 ° C. and was blown onto the glass substrate 103, and the temperature of the glass substrate 103 was set to 200 ° C. to perform the experiment.

The gate valve 102 was opened, a glass substrate was carried in from the load lock chamber, placed on the support 109, and the inside of the vacuum chamber 101 having a volume of 10 L was depressurized to 10 ^-8 Torr. Subsequently, the valve 107 is closed and the valve 115 is opened, and the heater 112 is operated to 300 ° C. from the gas outlet 111.
The heated N ₂ gas was supplied onto the glass substrate 103 at a flow rate of 1000 sccm. The glass substrate 103 was gradually raised and heated to about 200 ° C.

[0037] While the pressure in the vacuum processing chamber 101 is monitored by a pressure gauge 116, it continues to supply N ₂ gas until 1.1 kg / cm ^2, after the pressure reached 1.1 kg / cm ^2, the valve 115 Closed, the valve 107 is opened, and the turbo molecular pump 104 having an evacuation speed of 300 (l / sec) is closed.
Then, the inside of the vacuum processing chamber 101 was rapidly exhausted to 10 ⁻⁷ Torr in about 90 seconds by the roughing pump 105. N above
The operation of supplying _two gases and rapid evacuation (batch purge) was repeated several times.

After the batch purge is completed, the valve 107 is closed and N ₂ gas at room temperature is discharged from the gas outlet 111 for 1200 s.
ccm was supplied, and the inside of the vacuum processing chamber 101 was set to the atmospheric pressure. At atmospheric pressure, the valve 118 installed in the gas passage 117 was opened, and N ₂ gas was introduced into an atmospheric pressure ionization mass spectrometer (not shown). At this time, the temperature of the glass substrate 103 was heated to approximately 300 ° C. by the heater 110 so that the amount of water released from the glass substrate 103 could be measured by the atmospheric pressure ionization mass spectrometer.

FIG. 3 shows the relationship between the number of batch purges and the amount of released water. For comparison, the amount of moisture released from the surface of the glass substrate when the batch purging of this example is not performed is also shown in FIG.

As shown in FIG. 3, the amount of water released from the glass surface before batch purging was about 1000 ppb, but by performing the batch purging once, the amount of water released was about 20 ppb, and 5 times. About 1p by doing
It was found that the water content of pb and the supply gas can be reduced.

From the above results, according to the method of this embodiment,
It was revealed that the water adsorbed on the glass substrate 103 can be effectively removed.

Next, the batch purge was performed 5 times, and the amount of released water was measured when the temperature of the N ₂ gas at the N ₂ gas outlet 111 was changed. FIG. 4 shows the results. As shown in FIG. 4, even if the temperature of the glass substrate 103 is room temperature, it is possible to make the water content on the glass substrate 103 approximately 10 ppb by batch purge, and further raise the temperature of the glass substrate. As a result, it can be seen that the efficiency of removing adsorbed moisture increases.

In this embodiment, the gas used for batch purging is N 2 gas.
_{Although 2} gases were used, the same effect was confirmed not only with N ₂ gas but also with Ar. Further, the heated N ₂ gas was blown onto, for example, the glass substrate, but the temperature of the substrate was directly controlled by the heater 110.
The same tendency result is obtained when heating is performed at.

If the temperature of the substrate at the time of batch purging is room temperature or higher, the adsorbed water content can be effectively removed at various temperatures by controlling the number of batch purging.

(Embodiment 2) A second embodiment of the present invention will be described using the apparatus shown in FIG. In this example, an experiment was conducted to remove organic impurities adhering to the substrate surface by blowing ozone gas onto the substrate surface.

The glass substrate 103 is loaded into the vacuum processing chamber 101 from the load lock chamber, placed on the support 109, and the temperature of the glass substrate 103 is set to 200 ° C. as in the first embodiment.
After removing the adsorbed moisture from the substrate surface by the batch purge, the vacuum processing chamber 101 was evacuated to 10 ⁻⁸ Torr.

Next, the valve 122 is opened and the ozone gas 50
0 sccm was blown onto the glass substrate 103 from the blowout port 115. Incidentally, O ₂ ozone gas containing 10% N ₂
Gas in which a was generated by introducing the ozone generator, O ₃
Is a gas containing 2%.

The valve 107 was adjusted so that the pressure was 30 mmTorr, and the time during which ozone gas was supplied was maintained for 1, 2, 3, 5 and 10 minutes, respectively, and then the valve 1
22 was closed and the inside of the vacuum processing chamber 101 was evacuated to 10 ⁻⁸ Torr.

After opening the gate valve 102 and carrying the substrate to the load lock chamber, N ₂ gas was introduced into the load lock chamber, and the glass substrate was taken out under atmospheric pressure.

The amount of organic substances remaining on the surface of the taken-out glass substrate 103 was evaluated by a Fourier transform infrared spectrophotometer. The result is shown in FIG. For comparison, FIG. 5 also shows the measurement results of the untreated glass substrate.

For an untreated glass substrate, 1.2 × 10 ¹⁵
In contrast to the organic impurities of molecules / cm ^2, the amount of adsorbed organic substances on the substrate subjected to the ozone gas treatment of this example decreased sharply with the ozone gas treatment time, and the Fourier transform was performed when the treatment time was 3 minutes or more. It was found to be below the detection limit of the infrared spectrophotometer.

From the above results, it became clear that the present invention can remove the organic impurities remaining on the surface of the substrate.

In the present embodiment, the experiment was conducted under the condition that the temperature of the glass substrate was approximately room temperature. However, by heating the substrate,
It has been confirmed that a higher effect can be obtained. Also,
For example, by exciting the ozone gas using ultraviolet light, it is possible to efficiently remove the organic impurities on the glass substrate, for example, by using the ozone gas having a lower concentration than in the present embodiment.

Example 3 In this example, the same treatment as in Example 1 was performed using a polycarbonate substrate.

In this embodiment, heated N ₂ gas is blown onto the substrate so that the temperature of the substrate becomes 100 ° C., and the N ₂ gas is continuously supplied until the pressure in the vacuum processing chamber reaches 1.0 kg / cm ^2. After that, the gas was evacuated for 90 seconds by the turbo molecular pump 104 and the roughing pump 105 having an evacuation speed of 300 (l / sec). This operation was repeated 10 times. Other than this, the same as in Example 1.

Next, the gate valve 102 'is opened and the substrate is transported to a sputtering device (not shown) to deposit a Cr film of 100 nm.
A film was formed. The adhesive strength of the Cr film was evaluated by the tape test.
The Cr film was scratched with a knife at a pitch of 1 mm, the tape was attached, and then the tape was peeled off at once. For comparison,
The same evaluation was performed on the Cr film formed without performing the process of this example.

In the untreated Cr film, almost half of the Cr pieces were peeled off, whereas the Cr film of this example was not peeled off at all.
It was found that the treatment of this example can form a thin film having extremely excellent adhesion.

(Embodiment 4) In the present embodiment, as shown in FIG.
An element having the structure shown in (b) was manufactured using the thin film transistor manufacturing apparatus shown in FIG.

In FIG. 6, 601 is a load lock chamber,
Reference numeral 602 denotes a vacuum processing chamber having the same structure as in FIG.
Is a sputtering device, 604 is a PCVD device for SiN _x , 6
Reference numeral 05 is an i-type a-Si PCVD apparatus, and 606 is an n ⁺ -type a.
-Si PCVD apparatus, 607 is a transfer chamber for allocating the substrate to each processing apparatus.

First, the withstand voltage measuring element shown in FIG. 7A was prepared, and the effect of the treatment of the present invention on the withstand voltage was examined.

A cassette containing 10 glass substrates is installed in the load lock chamber 601 and the inside is evacuated. Then, the substrates are transferred and installed one by one in the vacuum processing chamber 602, and after processing, the cassette in the transfer chamber 607. Transported and stored inside. The treatment in the vacuum treatment chamber was carried out by treating with ozone gas for 5 minutes in the same manner as in Example 2, and subsequently by performing batch purging with N ₂ gas at 300 ° C. 5 times in the same manner as in Example 1.

Next, the substrates of the cassette are conveyed one by one to the sputtering chamber 603, and after forming a Cr film of 100 nm,
It was stored again in the cassette in the transfer room. After forming the Cr film on all the substrates, the glass substrate was returned to the cassette in the load lock chamber again and taken out to the outside.

After patterning the Cr film into a predetermined shape to form the lower electrode 702, the load lock chamber 601 is again formed.
Was placed in a cassette in a transfer chamber, and treated with ozone and N ₂ gas in the same manner as above. Subsequently, in SiN _x for PCVD apparatus 604 a-
SiN _x 703 was formed to a thickness of 300 nm. A for all substrates
After forming the —SiN _x film, the substrate was transferred to the sputtering chamber 603 to form a Cr film having a thickness of 100 nm and taken out of the load lock chamber in the same manner as above.

The Cr film is patterned into a predetermined shape to form the upper electrode 702 ', and a window is opened in the SiN _x film to take out the lower electrode.
100 devices having the structure of (a) were produced.

As a comparative sample, the vacuum processing chamber 6
An element having the structure of FIG. 7A was produced in the same manner as the sample of this example except that the treatment of 02 was not performed.

With respect to each of the samples manufactured as described above, the withstand voltage was measured on each of 10 substrates. As a result, the value of the comparative sample was 6.0 ± 1.0 MV / cm. Sample is 9.6 ± 0.2M
It was found that the variation was small in addition to the high breakdown voltage of V / cm.

Next, using the apparatus shown in FIG.
By the same operation as that of the element of (a), 10 substrates including 100 thin film transistors shown in FIG. 7B were manufactured.
Note that a-SiN _x (300 nm) 703, i-type a-S
i (100 nm) 704, n ⁺ type a-Si (20 nm)
Reference numeral 705 denotes PCVD devices 604, 605 and 606, respectively.
To continuously form a film. Also, Al706 is 2
A film was formed to a thickness of 00 nm.

In the case of the conventional thin film transistor, the breakdown of the insulating film (a-SiN _x ) occurred in a total of eight transistors due to static electricity, but the thin film transistor of this embodiment does not have any breakdown of the insulating film and is stable. It has been found that a thin film transistor can be manufactured.

Further, the characteristics of the transistor were stable, and the variation in the threshold value was ± 0.1 V, which was extremely stable. On the other hand, the conventional samples had a voltage of ± 2 V except for the broken samples.

[0070]

According to the present invention, a thin film having high adhesion and high quality can be formed even on a glass substrate or a plastic substrate, and as a result, a thin film transistor having higher performance and stable characteristics can be manufactured with a high yield. It will be possible.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of an impurity removal vacuum processing chamber of a thin film transistor manufacturing apparatus of the present invention.

FIG. 2 is a graph showing the relationship between N ₂ gas temperature and substrate temperature.

FIG. 3 is a graph showing the relationship between the amount of water released from a substrate and the number of batch purges.

FIG. 4 is a graph showing the relationship between the N ₂ gas temperature and the concentration of water released from the substrate.

FIG. 5 is a graph showing the relationship between ozone treatment time and the amount of residual organic impurities.

FIG. 6 is a conceptual diagram showing an example of a thin film transistor manufacturing apparatus of the present invention.

FIG. 7 is a conceptual diagram showing a structure of an element used for evaluation.

[Explanation of symbols]

101 vacuum processing chamber, 102, 102 'gate valve, 103 substrate, 104 turbo molecular pump, 105 roughing pump, 107, 115, 122 valve, 108, 108' vacuum exhaust passage, 109 substrate, 110 heating means (heater), 111 means for blowing out an inert gas, 112 gas supply passage, 113 heater, 114 mass flow controller, 114 pressure gauge, 119 ozone gas blowing means, 120 gas supply passage, 121 mass flow controller, 601 load lock chamber, 602 vacuum processing chamber, 603 sputter device 604 SiN _x for PCVD apparatus 605 i-type a-Si for PCVD apparatus 606 n ⁺ -type a-Si for PCVD apparatus 607 transfer chamber, 701 a glass substrate, 702, 702 'Cr film, 703 a-SiN _x 704 i-type a-Si, 705 n ⁺ -type a-Si, 706 Al film.

Claims (10)

[Claims] 1. A method for manufacturing a thin film transistor, which comprises manufacturing a thin film transistor on a glass substrate or a plastic substrate, wherein an inert gas heated to a predetermined temperature in a space in which the substrate is installed before forming a thin film forming the thin film transistor. Is introduced, and the substrate is brought into contact with the inert gas to remove impurities on the surface of the substrate. 2. A thin film transistor manufacturing method for manufacturing a thin film transistor on a glass substrate or a plastic substrate, wherein the substrate is placed in a state of being heated to a predetermined temperature before forming a thin film forming the thin film transistor. A method of manufacturing a thin film transistor, which comprises introducing an inert gas into a space and bringing the substrate into contact with the inert gas to remove impurities on the surface of the substrate. 3. The operation of introducing the inert gas until reaching a predetermined pressure, and then rapidly exhausting to a predetermined pressure at an exhaust speed of 300 (l / sec) or more is repeatedly performed. The thin film transistor manufacturing method according to claim 1 or 2. 4. The impurity concentration in the inert gas is 1 p
It is below pb, The thin film transistor manufacturing method of any one of Claims 1-3 characterized by the above-mentioned. 5. The method of manufacturing a thin film transistor according to claim 1, wherein ozone or a mixed gas containing ozone is used instead of the inert gas. 6. Prior to removing impurities by the inert gas, ozone or a mixed gas containing ozone is introduced into the space and brought into contact with the substrate, and then a vacuum state is set. 5. The method of manufacturing a thin film transistor according to any one of 1 to 4. 7. A thin film transistor manufacturing apparatus having at least one vacuum processing chamber for removing impurities on the surface of a glass substrate or a plastic substrate, and at least one film forming chamber for forming a thin film forming a thin film transistor on the substrate. The vacuum processing chamber has means for heating and blowing out an inert gas or / and ozone, exhaust means, and means for loading / unloading a substrate to / from the film forming chamber. Thin film transistor manufacturing apparatus. 8. The thin film transistor manufacturing apparatus according to claim 7, wherein the vacuum processing chamber has a heating unit for heating the substrate. 9. The exhaust means is 300 (l / sec)
The thin film transistor manufacturing apparatus according to claim 7, wherein the thin film transistor manufacturing apparatus has the above exhaust speed. 10. The chromium oxide passivation film is formed on the inner surface of the vacuum processing chamber.
9. The thin film transistor manufacturing apparatus according to any one of 9 above.