JPH04314856A - Sputtering system - Google Patents

Abstract

PURPOSE:To stabilize the pressure in a film forming chamber and to prevent the suction of a sputtering material into an exhaust hole and its leakage to the outside by forming the exhaust hole consisting of a meandering passage extending from the inside to outside of the film forming chamber in a mask in which a substrate is mounted. CONSTITUTION:A substrate 2 is introduced and mounted on the lower end face of a mask 421 and fixed in an envelope 423. A target 425 is opposed to the substrate 2 with the mask 421 in between to form a film forming chamber 422 in between. A magnet 427 is arranged above the target 425 and eccentrically driven by a motor 427a. Ar gas is introduced into the chamber 422 from a pipe 429 to sputter the target 425, and a film is formed on the substrate 2. In this sputtering system, an exhaust hole 421a consisting of a meandering passage of labyrinth is preferably formed in the mask 421 to communicate the chamber 422 with a transport chamber. Consequently, the pressure in the chamber 422 is not increased, and the sputtering material is deposited on the inner wall of the hole 421a and not diffused to the outside.

Description

[Detailed description of the invention]

[Purpose 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) film on the surface of a substrate such as a disk.

0002

2. Description of the Related Art Compact discs (hereinafter abbreviated as CDs) and optical discs have become widely used for recording large amounts of digitized audio information and image information. CD is made by sputtering aluminum with high light reflectance onto the surface of a transparent synthetic resin substrate such as polycarbonate.
A thin film layer is formed, and small holes called pits are made in the substrate according to digital information of "1" or "0", and the presence or absence of the holes is determined by the presence or absence of reflected waves of laser light. The recorded information can be read out. Since it is possible to form a thin film on one disk in a relatively short time, the configuration shown in FIG. 6 is adopted in order to continuously sputter a large number of disks.

FIG. 6 is a configuration diagram showing only the main mechanisms of a continuous sputtering apparatus. First, substrates 2 such as CDs, which are successively conveyed by an external conveyor 1 such as a belt conveyor, are rotated around an axis. Then, it is sucked by a suction pad 21 of a disk-shaped conveying device 3 that is movable in the vertical direction, and is conveyed to the sputtering chamber 4. In the sputtering chamber 4, the film is placed on a transport table 41 which is also rotatable about the axis and movable in the vertical direction, and sputtering film formation is sequentially performed by a sputtering source 42. The substrate 2 after sputtering film formation is again placed on the transport table 41 and taken out to the outside via the transport device 3.

By the way, the substrate 2 transported to the sputtering chamber 4
As shown in an enlarged view in FIG. 7, is pushed up by the transport table 41 so as to come into close contact with the lower end surface of the mask 421 of the sputtering source . A film forming chamber 422 in which sputter film formation is performed includes anti-adhesion shields 424a and 4 inscribed in an envelope 423.
24b and the mask 421, and exhaust is performed through the space 421a of the mask 421 when the substrate 2 is not present by a turbo molecular pump (not shown).

[0005] The substrate 2 is supported by a 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 is tightly fixed to the envelope 423 by utilizing its thermal expansion force. Further, the Al target 425 is fixed to the backing plate 426 and constitutes a cathode electrode, and together with the magnet 427 forms a magnetic field within the film forming chamber 422 . Note that the magnet 427 is attached to rotate eccentrically from the center of the film forming chamber 422, and the target 425 is used more efficiently by making the formed magnetic field uniform.

[0006] The cathode electrode has 7 points on the target 425 surface.
A discharge electric field of about 5 W/cm2 is formed, but in order to suppress the temperature rise of the target 425 during film formation to below 200 to 300 degrees Celsius, a ring-shaped cavity is formed in the backing plate 426, and a water supply pipe 428 is used to generate a discharge electric field. Cooling water is supplied. Furthermore, argon gas necessary for film formation is supplied into the film formation chamber 422 from a pipe 429 . The pressure used during film formation is within the range of 0.2 to 5.0 [Pa (Pascal)]. It is known that the internal pressure of this sputtering apparatus varies over a wide range as described above because the usage conditions differ depending on the user.

[0007] With the above configuration, the target 42 made of Al
5 is struck by argon gas atoms, a sputtering action occurs, and an Al film is formed on the surface of the substrate 2. After film formation, the discharge is stopped, and the substrate 2 is again placed on the transport table 41 and transported, and taken out via the transport device 3.

[0008] In the sputtering apparatus having the above configuration,
Film formation on the substrates 2 that are sequentially transported is performed in a short cycle of about 6 seconds per substrate, so the actual film formation is performed in an extremely short period of about 2 seconds while the electric field is being supplied to the target 425. be exposed. During film formation, the film formation chamber 422 is used as a mask 42.
Since the gas supply continues in a state where the substrate 1 and the substrate 2 are sealed, the pressure continues to rise even during the 2 seconds of film formation time. Therefore, the discharge current-voltage characteristics during film formation change, making it impossible to obtain stable film formation conditions.

In order to keep the pressure inside the film forming chamber 422 constant during film forming, several exhaust holes 423a are provided in the envelope 423 as shown in FIG. However, the Al sputtered during the film formation process also leaked through the exhaust hole 42.
3a to the transfer chamber side, contaminating the transfer chamber with Al, which was not an appropriate solution.

0010

[Problems to be Solved by the Invention] In conventional sputtering equipment, if the pressure inside the film forming chamber is not stable, or if an exhaust hole is provided to stabilize the pressure, the sputtering material cannot be used inside the exhaust hole of the envelope or in the transfer chamber. It became contaminated and could not be kept in good working condition.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sputtering apparatus that eliminates the above-mentioned conventional drawbacks and can always form a good film with good reproducibility.

[Configuration of the invention]

[0013]

[Means for Solving the Problems] A first aspect of the present invention provides a sputtering apparatus in which a disk is arranged such that a part of the film forming surface side is in close contact with a mask and faces a target in a film forming chamber. It is characterized in that the exhaust hole from the room to the outside is formed by a refraction path within the mask.

[0014] The second invention is a sputtering apparatus in which a disk is arranged so as to face a target in a film forming chamber while a part of the film forming surface side is in close contact with a mask, in which exhaust air is discharged from the film forming chamber to the outside. The mask is characterized in that the holes are formed by refraction paths having a labyrinth structure within the mask.

[0015]

[Operation] In the sputtering apparatus according to the present invention, the exhaust hole leading from the film forming chamber to the outside of the film forming chamber is formed in the mask as a refraction path. It can be absorbed inside and prevent it from leaking to the outside.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sputtering apparatus according to the present invention will be described below with reference to FIGS. 1 to 4. In addition,
Components that are the same as those of the conventional sputtering apparatus shown in FIGS. 6 and 7 are given the same reference numerals, and detailed explanations will be omitted.

That is, the substrate 2 transported via the transport device 3 is attached to the lower end surface of the mask 421 by the transport table 41. The film forming chamber 422 includes a mask 421, an anti-adhesion shield 424 inscribed in the envelope 423, and a target 4.
Consisting of a backing plate 426 to which 25 is fixed,
A magnet 427 is eccentrically located above the backing plate 426 and is eccentrically rotated by a motor 427a.

Therefore, argon gas is flowed into the film forming chamber 422 from a pipe 429, and an Al thin film is formed on the surface of the substrate 2 facing the target 425 by the sputtering action of the argon gas atoms. The discharge is stopped, and the substrate 2 is again placed on the transfer table 41 and taken out via the transfer device 3. In addition, the mask 42
1, as shown enlarged in FIGS. 2 to 4, in order to prevent a pressure increase in the film forming chamber 422 during film formation, the film forming chamber 422 is
A plurality of exhaust holes 421a are formed in the mask 421 and communicate with each other from inside to outside.
For example, a maze-like refraction path is formed that changes its direction by 90 degrees twice. The exhaust hole 421a is composed of a bent path, and the exhaust path from the film forming chamber 422 is correspondingly longer. Therefore, the Al component sucked into the exhaust hole 421a is adsorbed on the inner wall surface of the exhaust hole 421a, and the adsorption is also increased. Since the process proceeds from the side closer to the film forming chamber 422, Al contamination is prevented from coming out from the exhaust hole 421a and spreading toward the transfer chamber.

[0019] In a vacuum, most of the target material particles such as Al and gas particles are suspended in the atomic or molecular state and move while repeatedly colliding with each other. The distance from one collision to the next at that time is called the mean free path λ (mm), and in the case of argon or aluminum atoms, the length of this distance depends only on the pressure P [Pa]. However, the relationship between mean free path λ and pressure P is approximately λ=1
It is expressed as 0/P. Furthermore, molecules of a target material such as Al normally adhere to the wall after colliding with the wall once or twice at room temperature, and do not evaporate as a gas again and float. Exhaust hole 421a
The diameter D, length L, and size of the refraction angle are set in consideration of the pressure and mean free path at that time. The rate at which sputtered particles escape to the opposite side of the exhaust hole is 1/100.
00 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 as long as the inlet and outlet of the exhaust hole 421 are bent at least once to such an extent that they cannot be seen directly from each other, the effects of the present invention can be obtained in practice.

Therefore, in the refraction path shown in FIGS. 1 to 4, holes and grooves are formed by cutting, and then the lid 421
b can be formed by brazing to fix the exhaust hole 421a, but as another example, if the exhaust hole 421a is made of a simple bending path as shown in FIG. Can be formed simply by cutting. Note that Al accumulated in the exhaust hole 421a of the mask 421 can be easily removed by removing the mask 421 from the envelope 423 and immersing the entire mask in a caustic soda solution or a caustic potash solution. Furthermore, in each of the above embodiments, the shape of the mask 421 also has a substrate 2 supporting portion at the center, but the present invention is applicable even if the mask 421 does not necessarily have a substrate supporting portion at the center and is simply configured in a ring shape. Needless to say.

As described above, the sputtering apparatus according to the present invention has a simple configuration in which an exhaust hole 421a with a refraction path is provided in the removable mask 421, thereby preventing pressure fluctuations during film formation and exhausting Al contamination. Hole 421a
Since it is possible to keep the sputtering within the sputtering area and prevent it from spreading to other areas, it is possible to obtain stable film formation with high quality and reproducibility under constant sputtering conditions, which also improves the operating rate of the equipment. can be done.

[0022]

[Effects of the Invention] The sputtering apparatus according to the present invention has the following features:
There is little contamination of the transfer chamber by the sputtered material, and stable and good sputtering film formation is always possible under constant conditions, which is highly effective in practical use.

[Brief explanation 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 of the mask of the device shown in FIG. 1;

FIG. 3 is a perspective view showing an exhaust hole in the mask shown in FIG. 2;

FIG. 4 is a sectional view taken along line AA in FIG. 2;

FIG. 5 is a sectional view of a main part of a mask according to another embodiment of the sputtering apparatus according to the present invention.

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

7 is a cross-sectional view showing essential parts of the continuous sputtering apparatus shown in FIG. 6. FIG.

[Explanation of symbols]

1... External transport device 2... Substrate 3... Transport mechanism 4... Sputter chamber 41... Transport table 42... Sputter source 421... Mask 421a... Exhaust hole 422... Film forming chamber 423... Envelope 424, 424a, 424b... Anti-adhesion shield 425...Target 427...Magnet 429...Tube

Claims (2)

[Claims] 1. A sputtering apparatus in which a substrate is arranged such that a part of the film forming surface side is in close contact with a mask and faces a target in a film forming chamber, wherein an exhaust hole from the film forming chamber to the outside is connected to the mask. A sputtering device characterized by comprising a refraction path inside. 2. A sputtering apparatus in which a substrate is arranged such that a part of the film forming surface side is in close contact with a mask and faces a target in a film forming chamber, wherein an exhaust hole from the film forming chamber to the outside is connected to the mask. A sputtering device characterized by having a refraction path with a labyrinth structure inside.