JPH0639691B2 - Continuous sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sputtering apparatus suitable for forming, for example, an Al (aluminum) coating on the surface of a substrate such as a disk.

[0002]

2. Description of the Related Art Compact discs (hereinafter abbreviated as CD) and optical discs have been widely used for recording a large amount of digitized voice information and image information. CD is made of Al with high light reflectance by sputtering on the surface of a transparent synthetic resin substrate such as polycarbonate.
A thin film layer is formed, and a small hole called a pit is made in the substrate according to the digital information of "1" or "0", and the presence or absence of the hole depends on the presence or absence of the reflected wave of laser light. The recorded information can be read. Since a thin film can be formed on one disk in a relatively short time, the structure shown in FIG. 6 is adopted to continuously sputter many disks.

FIG. 6 is a block diagram showing only the main mechanism of a continuous sputtering apparatus. First, a substrate 2 such as a CD, which is successively conveyed by an external conveying apparatus 1 such as a belt conveyor, rotates around an axis. Also, it is adsorbed by the adsorption pad 21 of the disk-shaped transfer device 3 which is movable in the vertical direction, and transferred to the sputtering chamber 4. In the sputtering chamber 4, the substrate is placed on a transport table 41 that is also rotatable about the axis and movable in the vertical direction, and sputtering film formation is sequentially performed by the sputtering source 42. The substrate 2 after the sputtering film formation is placed on the transfer table 41 again, and taken out through the transfer device 3 to the outside.

By the way, the substrate 2 carried to the sputtering chamber 4
7 is pushed up by the transport table 41 so as to be in close contact with the lower end surface of the mask 421 of the sputtering source 42, as shown in an enlarged view in FIG. Deposition chamber 422 for sputter deposition
Is the deposition shield 424a inscribed inside the envelope 423,
424b and the mask 421, the exhaust air passes through the space 421a of the mask 421 when the substrate 2 is not present,
It is performed by a turbo molecular pump (not shown).

The substrate 2 is supported by the mask 421, and the non-film-forming portion of the substrate 2 is shielded by the mask 421.
The mask 421 is manufactured with high precision, and the thermal expansion force of the mask 421 is used to tightly fix the mask 421 to the envelope 423. The Al target 425 is fixed to the backing plate 426 to form a cathode electrode, and forms a magnetic field in the film forming chamber 422 together with the magnet 427. The magnet 427 is attached so as to eccentrically rotate from the center of the film forming chamber 422, and the utilization efficiency of the target 425 is improved by making the forming magnetic field uniform.

The cathode electrode is 7 on the surface of the target 425.
A discharge electric field of about 5 W / cm ² is formed, but in order to suppress the temperature rise of the target 425 during film formation to 200 to 300 degrees Celsius or less, a ring-shaped cavity is formed in the backing plate 426 and the water supply pipe 428 is used. Cooling water is supplied. Further, an argon gas required for film formation is supplied into the film formation chamber 422 from a pipe 429. The pressure during film formation is used within the range of 0.2 to 5.0 [Pa (Pascal)]. It is known that the internal pressure of the sputtering apparatus varies over a wide range as described above because the usage conditions vary depending on the user.

With the above structure, the target 42 made of Al is formed.
5 is hit with argon gas atoms to cause a sputtering action, and an Al film is formed on the surface of the substrate 2. After the film formation, the discharge is stopped, the substrate 2 is again placed on the transport table 41 and transported, and is taken out through the transport device 3.

In the sputtering apparatus having the above structure,
Since the film formation on the substrates 2 that are sequentially conveyed is performed in a short cycle of about 6 seconds per sheet, the actual film formation operation is performed within an extremely short time of about 2 seconds while supplying the electric field to the target 425. Be seen. During the film formation, the film formation chamber 422 keeps the mask 42
Since the gas supply is continued in the state of being hermetically sealed by 1 and the substrate 2, the pressure continues to rise even during the film formation time of 2 seconds. Therefore, the discharge current-voltage characteristics during film formation change and stable film formation conditions cannot be obtained.

In order to keep the pressure inside the film forming chamber 422 constant during the film formation, as shown in FIG. 7, the envelope 423 is provided with several exhaust holes 423a so that the pressure to the transfer chamber side is increased. Although escaped, the Al sputtered during the film formation process also has exhaust holes 42.
It flows through 3a to the transfer chamber side and contaminates the transfer chamber with Al, which is not an appropriate solution.

[0010]

In the conventional sputtering apparatus, if the pressure in the film forming chamber is not stable or if an exhaust hole is provided so as to stabilize the pressure, the inside of the exhaust hole of the envelope and the transfer chamber are made of sputtered material. It was contaminated and it was not possible to maintain a good use condition.

An object of the present invention is to solve the above-mentioned conventional drawbacks and to provide a sputtering apparatus which can always obtain a good film with good reproducibility.

[Constitution of Invention]

[0013]

According to a first aspect of the present invention, a film forming chamber for forming a film on a substrate by sputtering, a transfer chamber for transferring the substrate to the film forming chamber, and a part of a partition wall of the film forming chamber. The continuous sputtering apparatus includes a mask that closely adheres the mask to the transfer chamber side and a refraction path that is provided in the mask and serves as an exhaust hole from the film forming chamber to the outside.

A second invention is that the refracting path of the first invention has a labyrinth structure.

[0015]

In the sputtering apparatus according to the present invention, the mask is provided with the exhaust hole extending from the film forming chamber to the outside of the film forming chamber by the refraction path in the mask. Therefore, the sputter material such as Al sputtered in the film forming chamber is exhausted through the exhaust hole. It can be prevented from being adsorbed inside and leaking to the outside.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sputtering apparatus according to the present invention will be described below with reference to FIGS. In addition,
The same components as those of the conventional sputtering apparatus shown in FIGS. 6 and 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

That is, the substrate 2 transferred through the transfer device 3 is attached to the lower end surface of the mask 421 by the transfer table 41. The film formation chamber 422 includes the deposition shield 424 and the target 4 that are inscribed in the mask 421 and the envelope 423.
25 is a backing plate 426 fixed,
Above the backing plate 426, an eccentrically positioned magnet 427 is eccentrically rotated by a motor 427a.

Therefore, argon gas is introduced into the film forming chamber 422 from the tube 429, and an Al thin film is formed on the surface of the substrate 2 facing the target by the sputtering action of the target 425 by the argon gas atoms. Discharge is stopped, the substrate 2 is placed on the transport table 41 again, and is taken out via the transport device 3. Also, the mask 42
As shown in FIG. 2 to FIG. 4 in an enlarged manner, in FIG. 1, the film forming chamber 42 is provided in order to prevent a pressure increase in the film forming chamber 422 during film forming.
2. A plurality of exhaust holes 421a communicating from the inside to the outside are formed, and the exhaust holes 421a form a refracting path in the mask 421, for example, a labyrinth-like refracting path that changes its direction by 90 degrees. . The exhaust hole 421a is constituted by a refraction path, and the exhaust path from the film forming chamber 422 is lengthened accordingly. Therefore, the Al sucked into the exhaust hole 421a is formed.
Since the components are adsorbed on the inner wall surface of the exhaust hole 421a and the adsorption proceeds from the side closer to the film forming chamber 422 side, it is possible to prevent Al contamination from spreading from the exhaust hole 421a to the transfer chamber side.

Most of the particles of the target material such as Al and the gas particles in a vacuum are floating in an atomic or molecular state, and move while repeatedly colliding with each other. The distance from one collision to the next is called the mean free path λ (mm), and the length of this distance depends only on the pressure P [Pa] in the case of argon or aluminum atoms. However, the relationship between the mean free path λ and the pressure P is approximately λ = 1.
It is represented by 0 / P. Further, when the molecules of the target material such as Al normally collide with the wall once or twice at room temperature, they will adhere to the wall and will not evaporate and float again as a gas. Exhaust hole 421
The diameter D, the length L, and the size of the refraction angle of a are set in consideration of the pressure and the mean free path at that time. The ratio of sputtered particles that escape to the opposite side of the exhaust hole is 1/10
000 or less, when the diameter R of the exhaust hole 421 is made smaller than λ / 2, at least the length L of the exhaust hole 421 is 3R or more, and moreover, at least between the inlet and the outlet of the exhaust hole 421 are at least one another. If it is refracted once to the extent that it cannot be seen directly, the effect of the present invention can be obtained in practical use.

Therefore, the bending path shown in FIGS. 1 to 4 has holes and grooves formed by cutting, and then the lid 42 is formed.
1b can be formed by brazing fixing, but as another embodiment, the exhaust hole 421a having a simple bent path as shown in FIG. It can be formed simply by cutting. The Al accumulated in the exhaust holes 421a of the mask 421 can be easily washed and removed by removing the mask 421 from the envelope 423 and immersing the whole in a caustic soda solution or a caustic potash solution. Further, in each of the above embodiments, the shape of the mask 421 also has the substrate 2 supporting portion in the central portion, but the present invention is applicable even when the mask 421 is not necessarily provided with the substrate supporting portion in the central portion and is simply formed into a ring shape. Needless to say.

As described above, the sputtering apparatus according to the present invention has a simple structure in which the exhaust hole 421a is provided in the removable mask 421 by the refraction path so as to prevent the fluctuation of the pressure during the film formation and exhaust the Al contamination. Hole 421a
Since it can be retained inside and prevented from diffusing to other areas, it is possible to obtain stable film formation with high quality and reproducibility under constant sputtering conditions, and also improve the operating rate of the equipment. Can be made.

[0022]

The sputtering apparatus according to the present invention is
There is little contamination of the transfer chamber by the sputter material, and stable and favorable sputter film formation is always possible under constant conditions, which is a great effect obtained in practical use.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a sputtering apparatus according to the present invention.

FIG. 2 is an enlarged perspective view showing a mask of the apparatus shown in FIG.

FIG. 3 is a perspective view showing an exhaust hole in the mask shown in FIG.

4 is a cross-sectional view taken along the line AA of FIG.

FIG. 5 is a cross-sectional view of an essential part of a mask according to another embodiment of the sputtering apparatus of the present invention.

FIG. 6 is a configuration diagram showing a conventional continuous sputtering apparatus.

7 is a cross-sectional view showing the main parts of the continuous sputtering apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... External transfer device 2 ... Substrate 3 ... Transfer mechanism 4 ... Sputtering chamber 41 ... Transfer table 42 ... Sputtering source 421 ... Mask 421a ... Exhaust hole 422 ... Film forming chamber 423 ... Envelopes 424, 424a, 424b ... Preventing shield 425 ... Target 427 ... Magnet 429 ... Tube

Claims (2)

[Claims] 1. A film forming chamber for forming a film by sputtering on a substrate,
A transfer chamber for transferring the substrate to the film forming chamber, and
A part of the partition wall that adheres the substrate to the transfer chamber side.
And a mask provided inside the mask and out of the film forming chamber.
Continuous sputtering device consisting of a refraction path that becomes the exhaust hole of the . Tulling device. 2. A film forming chamber for forming a film on a substrate by sputtering, and
A transfer chamber for transferring the substrate to the film forming chamber, and
A part of the partition wall that adheres the substrate to the transfer chamber side.
And a mask provided inside the mask and out of the film forming chamber.
Continuous spattering device including a labyrinth-shaped refraction path serving as an exhaust hole .