JPH03197671A - Film forming device by high-frequency sputtering - Google Patents

Abstract

PURPOSE:To constitute a film forming device by high-frequency sputtering which is capable of low temp. film formation and high speed build-up by specifying the ratio of the whole surface area of the grounded part which forms the plasma space in a film formation chamber to the surface area of a target. CONSTITUTION:A base plate 8 is set on the opposite face of a target 5 in a film formation chamber 1. This film formation chamber 1 is exhausted to the prescribed pressure by an exhauster 10. Then the gas to be sputtered is introduced into the chamber 1 via an introduction valve 7. High frequency is impressed to the target 5 from a power source 6 and plasma is excited in the discharge space and film formation is performed on the base plate 8. At this time, a movable plate 2 provided in the chamber 1 is fixed in the proper position by a jig 5 to ground the movable plate 2 on the inner wall of the chamber 1. The plasma space is controlled so that the SE/ST of the whole surface area (SE) of the grounded part which forms the plasma space to the surface area (ST) of the target is regulated to >=10. Thereby low-temp. film-formation is performed while utilizing high frequency and maintaining the build-up velocity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a sputtering film forming apparatus using a high frequency power source.

[Description of prior art]

Conventional sputtering film forming apparatuses have two types of power introduction methods: direct current and high frequency. The advantage of direct current is low cost, and the advantage of high frequency is that power can be stably input and dielectric films can be formed. However, sputtering has a deposition rate nearly an order of magnitude lower than conventional deposition by vapor deposition. Magnetron sputtering has improved this drawback. In other words, a magnetic field traps electrons on the target surface and creates a large amount of ions, increasing the deposition rate.

[Problems to be Solved by the Invention] When forming a dielectric film by sputtering, a high frequency is usually used. However, in the case of high frequency, the deposition rate is slow even with magnetron sputtering, so higher input power is required.

At this time, the temperature rise cannot be ignored, and resin substrates with a large coefficient of thermal expansion are easily deformed, so that the range of their use has been limited. In recent years, magnetic disks and magneto-optical disks have attracted attention as next-generation information recording media.For example, in the case of a magneto-optical disk, the information written on the bits is read by shining a laser beam onto the disk, but the signal is very small. Therefore, high precision (for example, flatness) is required for the substrate. On the other hand, the use of resin substrates is desired for the purpose of cost reduction, but resin substrates have the problems described above.

[Purpose of the invention]

The present invention aims to solve the above-mentioned problems by providing a high-frequency sputtering film forming apparatus capable of low-temperature film formation and high-speed deposition.

[Structure of the invention]

The present invention was completed as a result of intensive research to achieve the above object in a sputtering film forming apparatus using a high frequency power supply. (SZ) and target surface area (ST), SZ/ST, is 10 or more.

The present invention will be described below with reference to the drawings.

As an example of the technical means necessary for the solution of the present invention, a film forming apparatus as shown in FIG. 1 was proposed.

Honnari W! The characteristics of the 4 devices are the plasma space (Fig. 5 (A)
The total surface area in contact with the ground forming the shaded area (■) in Figure 5 (B)
In order to vary the shaded area (■), a movable plate 2 is provided inside the film forming chamber l in FIG. is grounded. The movable plate 2 adjusts the plasma space as shown by the arrow in FIG.

The mechanism of the device will be explained.

A substrate 8 is placed on the opposite surface of the target 5.

The film forming chamber 1 is evacuated to a predetermined pressure by an exhaust device 10 by opening a vacuum valve 9. Thereafter, the gas introduction valve 7 is opened to introduce sputtering gas, and for film formation, high frequency waves are applied to the target 5 from the high frequency power source 6 to excite plasma in the discharge space. 4 is a guard electrode that prevents a backing plate (not shown) with a target from being sputtered.According to the present invention, the entire ground surface area forming the plasma space (the diagonal line in FIG. 5 (B')) S,) and the target surface area (hatched area in Figure 5 (C); ST)
By setting v/St to 10 or more, it is possible to suppress a rise in substrate temperature and increase the deposition rate. Note that the present invention has the same effect whether it is a device having a mechanism for changing S as shown in FIG. 1 or a fixed wall device where Sx/Sr satisfies 10 or more.

〔Example〕

A dielectric film was formed using the high frequency sputtering film forming apparatus shown in FIG.

Silicon nitride was used as the target 5, and a polycarbonate substrate 8 was set. First, the film forming chamber l is 2x10''
' Torr was exhausted, and then Ar gas was introduced through the gas introduction valve 7, and the Ar gas pressure in the film forming chamber 1 was set to 2 x 10-'' Torr. Sx/Sr 3゜10.30, 60.80
, the deposition rate was calculated by forming a film for 1 hour with a high frequency input power of 800 W, f, knee, St /sr -1
Figure 2 shows the relative deposition rate when the deposition rate at 0(7) is set to 1.0 - The relative deposition rate increases as SE /ST increases, and becomes almost constant above 60. .

A thermolabel is pasted on the main polycarbonate substrate 8, and Ar
The pressure is 2 x 10-3 Torr, and the input power is 8 as before.
The film formation time was adjusted for each St/Sr so that the thickness of the silicon nitride film was 3000 at 00W, and the change in thermolabel of the substrate 8 was investigated, and the results are shown in FIG. SE/S? If the temperature is 3060.80, no change is observed in the thermolabel, and the temperature below the lower limit of the thermolabel is 50°C.
When x/Sr is 10, it is 50 to 55°C, which is a temperature that poses no problem for the resin, and it is sufficient if SE/37 is 10 or more.

On the other hand, in order to form a film at the same deposition rate, the high-frequency input power was varied under each SZ/STO ratio, and when the deposition rates were plotted and connected, it was found that each of them passed through the origin.

From this, we derived the high-frequency input power that would give the same deposition rate. As in Example 2, each SE/ST was set, and the thermolabel was deposited on the polycarbonate substrate 8 on which the thermolabel was attached by depositing the silicon nitride film at the same deposition rate for a predetermined time so that the film thickness was 3000 nm. The changes were investigated and the results are shown in Figure 4. When this deposition rate was adjusted to the deposition rate for Sx/Sr-10 so that it could be compared with the graph in Figure 3, it was found that in the case of SE/5T-3, the substrate temperature increased due to the input of higher power than the light. The thermolabel read 120° C., and deformation of the polycarbonate substrate 8 was confirmed.

Conversely, if SE/ST is 10 or more, the substrate temperature is 55°C.
Since there is no deformation of the substrate, there is no problem in use, and it is possible to increase the deposition rate while lowering the input power.

From the above Examples 1 to 3, it became possible to form a film on the substrate at low temperature while maintaining the deposition rate with low input power when S t /S t was set to 10 or more. This has made it possible to use a resin substrate even when forming a dielectric film using high frequency.

〔Effect of the invention〕

As explained above, by setting SZ/ST to 10 or more, low-temperature film formation is possible while maintaining the deposition rate using high frequency.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing a typical example of the high frequency sputtering film forming apparatus of the present invention, and FIGS. 2 to 4 are correlation diagrams between SE/ST and relative deposition rate. FIG. 5(A) is a diagram showing the plasma space, and FIG. 5(B) is a diagram showing the plasma space.
is a diagram showing the total ground surface area. Figure 5 (C) is:
It is a figure showing a target surface area. In the figure, l... film forming chamber, 2... movable plate, 3...
・Jig, 4... Guard electrode, 5... Target, 6
...High frequency power supply, 7...Gas introduction valve, 8...
Resin substrate, 9... Vacuum pulp, 10... Exhaust device. Figure SE/5T SE/ST 0 Figure 0 306080 Sε/ST Figure (A) Figure (B) Figure (C)

Claims (1)

[Claims] In a sputtering film forming apparatus using a high frequency power supply, the total surface area of the grounded part that forms the plasma space (S_Z
) and target surface area (S_T), S_Z/S_T, is 10 or more.