JPH06145983A - Thin film forming device - Google Patents

Abstract

PURPOSE:To reduce an initial cost without using a costly pump for a spare chamber. CONSTITUTION:This thin film forming device has a film forming chamber 1 where a thin film is formed on a substrate 2 and the vacuum evacuated spare chamber 3 which is provided via a gate valve 4 at the film forming chamber 1 and through which the substrate 2 is transported to the film forming chamber 1. The relation between volume V1 and V2 is so determined as to satisfy the following equation: V1/V2>=(P2-P)/(P-P1) when the volume of the film forming chamber 1 is designated as V1, the vacuum degree which can be attained as P1, the vacuum degree necessary at the time of film formation as P, the volume of the spare chamber 3 as V2 and the vacuum degree which can be attained as P2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film forming apparatus having a film forming chamber for forming a thin film on a substrate and a vacuum evacuation preliminary chamber via a gate valve.

[0002]

2. Description of the Related Art A conventional thin film forming apparatus has a structure shown in FIG. 3 in the case of aluminum. In the figure,
Reference numeral 1 is a film forming chamber for forming an aluminum thin film on a substrate 2 which has been carried in, 3 is a vacuum evacuation preparatory chamber provided through an inner gate valve 4, 5 is an outer gate valve outside the preparatory chamber 3, and 6 is A turbo molecular pump provided in the auxiliary chamber 3 via a pump side gate valve 7, a rotary pump 8 connected to the turbo molecular pump 6 via a pump side valve 9, and a transfer arm 10.

Then, the outer gate valve 5 is opened, the substrate 2 is mounted on the arm 10, the valve 5 is closed, the preliminary chamber 3 is evacuated by the rotary pump 8, and the turbo molecular pump 6 is evacuated to a high vacuum. On the other hand, the film forming chamber 1 has been evacuated to a high vacuum by a turbo molecular pump in advance, and the inner gate valve 4 is opened in a state where the degree of vacuum in the auxiliary chamber 3 is about the same as that of the film forming chamber 1 and the substrate is moved by the arm 10. 2 is loaded into the film forming chamber 1 and the valve 4 is closed to form a film.

After the film formation, the inner gate valve 4 is opened to transfer the substrate 2 to the preliminary chamber 3, the valve 4 is closed, the outer gate valve 5 is opened to discharge the substrate 2, and then the film formation is performed. The substrate 2 to be carried is loaded into the preliminary chamber 3 and the outer gate valve 5
Is closed, the preliminary chamber 3 is evacuated by the rotary pump 8 and the turbo molecular pump 6, and the above film forming operation is repeated.

[0005]

When an aluminum thin film was formed on a substrate and an experiment was conducted to obtain a stable and high reflectance, the results shown in FIG. 2 were obtained when the film forming rate was 3000 Å / min. That is, in order to obtain a reflectance of 82.5% or more, the film forming chamber needs a vacuum higher than 6 × 10 ⁻⁵ Torr.

Since the film forming chamber 1 shown in FIG. 3 is evacuated by using a turbo molecular pump, it can be evacuated to a high vacuum of 1 × 10 ^-7 Torr. In order to prevent the film forming chamber 1 from having a vacuum lower than the above 6 × 10 ⁻⁵ Torr, a high vacuum must be set, and in addition to the rotary pump 8, an expensive turbo molecular pump 6 must be used together, which results in equipment cost. Is very expensive. The present invention has been made in consideration of the above points, and an object of the present invention is to provide a thin film forming apparatus that does not use an expensive pump for a preliminary chamber and has a low equipment cost.

[0007]

In order to solve the above problems, a thin film forming apparatus of the present invention comprises a film forming chamber for forming a thin film on a substrate and a substrate provided in the film forming chamber via a gate valve. A vacuum evacuation spare chamber for transporting the film to the film chamber is provided, and the volume of the film formation chamber is V1, the attainable vacuum degree is P1, the required vacuum degree during film formation is P, the reserve chamber volume is V2, and the attainable vacuum degree is When P2 is set, the relationship between the volumes V1 and V2 satisfies the following equation. V1 / V2 ≧ (P2-P) / (P-P1)

[0008]

In the thin film forming apparatus of the present invention configured as described above, the volume relationship between the film forming chamber and the preliminary chamber is regulated from the attainable vacuum degree of both chambers and the required vacuum degree of the film forming chamber, Since the volume of the preliminary chamber is small, an expensive turbo molecular pump or the like can be used for vacuum exhaust of the preliminary chamber, and only an inexpensive rotary pump can be used, resulting in a low equipment cost.

[0009]

EXAMPLE One example will be described with reference to FIG.
In the figure, the same reference numerals as those in FIG. 3 indicate the same or corresponding ones, except that the turbo molecular pump 6 of FIG. 3 is not provided and the pump for the preliminary chamber 3 is only the rotary pump 8, The volume is smaller than the predetermined ratio with respect to the film forming chamber 1, in other words, the volume of the film forming chamber 1 is larger than the predetermined ratio with respect to the preliminary chamber 3.

That is, now, the volume of the film forming chamber 1 is V1, the attainable vacuum degree is P1, the required vacuum degree at the time of film formation, that is, immediately before film formation is P, the volume of the preliminary chamber 3 is V2, and the attainable vacuum degree is When P2, the following formula is established. P1 * V1 + P2 * V2 = P * (V1 + V2) Therefore, V1 / V2 = (P2-P) / (P-P1) When the inner gate valve 4 is opened, at least the required degree of vacuum P is required. Make the relation satisfy the following formula.

V1 / V2 ≧ (P2-P) / (P-P1) Now, P1 is 1 × 10 ⁻⁷ Torr and P2 is 1 × 10 ⁻³ Tor.
If r and P are 6 × 10 ⁻⁵ Torr, V1 / V2 ≧ 1
It becomes 5.69, V1 is 15.7 times or more of V2, and V2 is 0.064 times or less of V1.

[0012]

Since the present invention is configured as described above, it has the following effects. In the thin film forming apparatus of the present invention, the relationship between the volume of the film forming chamber and the preliminary chamber is regulated from the attainable vacuum degree of both chambers and the required vacuum degree of the film forming chamber,
The volume of the film forming chamber is larger than the volume of the preliminary chamber by a predetermined ratio, or the volume of the preliminary chamber is smaller than the volume of the film forming chamber by a predetermined ratio or less. It is possible to use only an inexpensive rotary pump without using an expensive turbo molecular pump or the like, and it is possible to reduce the equipment cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram of one embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the degree of vacuum and the reflectance of aluminum.

FIG. 3 is a schematic view of a conventional example.

[Explanation of symbols]

 1 film forming chamber 2 substrate 3 spare chamber 4 gate valve V1 volume V2 volume P1 attainable vacuum degree P2 attainable vacuum degree P required vacuum degree

Claims (1)

[Claims] 1. A film forming chamber for forming a thin film on a substrate, and a vacuum evacuation preliminary chamber which is provided in the film forming chamber via a gate valve and conveys the substrate to the film forming chamber. When the volume is V1, the attainable vacuum degree is P1, the required vacuum degree during film formation is P, the volume of the preliminary chamber is V2, and the attainable vacuum degree is P2, the relationship between the volumes V1 and V2 is A thin film forming apparatus that is satisfied. V1 / V2 ≧ (P2-P) / (P-P1)