JPH0241165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for forming a thin film using low-temperature plasma, and in particular, an apparatus in which the sample holder is configured as a rotating disk to obtain a desired thin film in multiple stages. It is.

In recent years, the importance of thin film technology has increased in electronics,
It is recognized in many fields such as the chemical industry. This invention utilizes the chemistry of low-temperature plasma to form a thin film under reduced pressure, and can be applied to plasma polymerization or plasma CVD.

That is, the present invention provides an apparatus for forming a thin film using low-temperature plasma, in which an outer box has upper and lower processing chambers that are airtightly partitioned by a double partition wall and an inert gas storage chamber inside. A disk-shaped sample holder, which has a plurality of recesses for mounting samples on the front and back surfaces at positions approximately equidistant from the center, is rotatably inserted into the slit provided in the partition plate in advance to open the upper and lower processing chambers. The upper and lower processing chambers, the inert gas storage chamber, and the upper and lower processing chambers are provided with two pairs of electrode plates facing each other at corresponding positions in the upper and lower processing chambers. The present invention provides a multi-stage thin film forming apparatus using plasma, which is equipped with a gas supply pipe leading to a gas supply pipe, an exhaust pipe, a power supply circuit connected to upper and lower electrode plates, and a rotating mechanism for a disk-shaped sample holder.

Embodiments of the present invention will be explained with reference to the drawings: 1
is an outer box, which is made up of two vertical tubes 3, 3 having flanges at both ends placed on a bottom plate 2, with a partition plate consisting of two upper and lower plates 4, 4 such as upper and lower soft membrane bodies sandwiched between them. An active gas storage chamber 5 is provided, and a lid plate 6 is provided at the upper end.
The upper and lower processing chambers 7 and 8 are formed into a single sealed tank.

Inside this outer box 1, a disk-shaped sample holder 10 is provided with shallow recesses 9, 9, 9, 9 for mounting a sample at corresponding positions on the front and back surfaces of one disk, sandwiching the center. A central shaft 11 is vertically installed in a hermetically sealed manner through slits formed in the plates 4, 4 to prevent gas from mixing in the upper and lower processing chambers, and is provided horizontally along the upper surface of the inert gas storage chamber 5. It is designed to be rotated at low speed by a motor 12 provided externally via a universal joint. In addition, the upper and lower processing chambers 7,
Inside 8 are a pair of upper electrode plates 1 for plasma generation, sandwiching the disk-shaped sample holder 10 from the front and back.
3, 13 and lower electrode plates 14, 14 are erected by supports 15, 15 so as to face the recesses 9, respectively.

In addition to the moat 12, the outer box 1 has gas supply pipes 16 and 17 leading to the upper and lower processing chambers 7 and 8, and an inert gas supply pipe 18 leading to the inert gas storage chamber 5, one end of which is connected to a predetermined supply line. An exhaust pipe 1 from the upper processing chamber 7 is provided on the opposite side.
9. Exhaust pipe 2 from the lower processing chamber passing through the bottom plate 2
0. Similarly, the upper end is branched into three locations as shown by dotted lines in FIG. 2, and an exhaust pipe 2 is connected from the inert gas storage chamber 5.
1 is arranged in each case. Further, on the circumferential surface of the outer box 1, there are power supply circuits 22, 23 connected to the upper and lower electrode plates 13, 13, 14, 14, and one end connected to the upper and lower processing chambers 7,
8 and pressure sensors 24, 25, and 26 facing into the inert gas storage chamber 5 are provided.

The present invention has the above-mentioned configuration, and in order to use it, open the cover plate 6 of the outer box and place the disc-shaped sample holder 10 in place.
After fitting and mounting the thin film as a sample into the concave portions 9, 9, 9, 9, the sample take-out port is closed, and while the upper and lower processing chambers 7, 8 are simultaneously evacuated, the required gases are introduced into each of them to a predetermined value. After applying the pressure, the disk-shaped sample holder 10 is rotated, and the upper and lower electrode plates 13, 13, 1
High frequency power is applied to either or both of 4 and 14 to perform plasma treatment. At this time, the sample passes alternately through the upper and lower processing chambers 7 and 8 as the holder rotates, and a thin film having the desired composition and structure is formed. Further, when operating under conditions where there is a pressure gradient between the upper and lower processing chambers 7 and 8, balance is maintained by flowing an inert gas into the inert gas storage chamber 5, which is a partition wall. The presence or absence of gas mixing in the upper and lower processing chambers 7 and 8 can be detected by monitoring the plasma emission spectrum with a spectrometer. The pressure inside the container during the plasma polymerization reaction is usually different from that before the reaction starts; under conditions where polymerization mainly occurs, the pressure decreases, and on the contrary, under conditions where decomposition mainly occurs, the pressure increases. Furthermore, in the case of a membrane raw material gas that polymerizes quickly, increasing the flow rate may actually reduce the pressure inside the container. In general, for gases containing oxygen and fluorine, the pressure inside the container often increases under high power conditions, and conversely, for gases containing unsaturated compounds, cyclic compounds, nitrogen, and silicon, the pressure often decreases even under high power conditions. .
The above-mentioned tendencies regarding pressure changes vary depending on the gas, so check the pressure changes for each type before balancing the two chambers.

Several different modes of operation are possible with the device of the invention, as described below.

(1) Rotate the disk 180° at regular intervals to form a laminated film. In this case, it is sufficient to supply membrane raw material gas and electric power to each processing chamber for a certain period of time for the substrate membrane.

(2) Rotation speed of the disc-shaped sample holder 10 or
By gradually changing the interval of 180° rotation, a thin film with a certain chemical structure distribution in the thickness direction can be formed. In this case, it is necessary to supply gas and power to both chambers simultaneously.

(3) Electric power is supplied to only one processing chamber while rotating the disk-shaped sample holder 10 at a constant rate and supplying the same gas to both chambers.

The characteristics of each operation mode are as follows.

In the case of operation mode (1), while the substrate film is being processed in one processing chamber, gas is not supplied to the other, so there is no mixing of both gases, and since the processing chambers are separate, plasma sputtering, etc. Therefore, it is possible to prevent mixing of component elements and form a clear laminated film.

In case (2), unlike the case where a mixture of two gases is supplied into the plasma and the mixture composition is gradually changed, there is no mutual reaction between the gases in the plasma, so the chemical structure of the produced film is comparable. targets are more predictable and easier to control.

In the case of (3), the accumulation of radicals in the plasma-polymerized membrane, which has been a problem in the past, can be suppressed by contacting the raw material gas during the half cycle, and changes in membrane performance over time can be reduced. However, similar effects
This has also been observed when power is supplied as continuous pulses, but it is impossible to monitor the power, but strict monitoring is possible with the device of the present invention.

As described above, the present invention is unique in that existing general-purpose plasma film forming apparatuses do not have the ability to perform plasma thin film forming operations using the same apparatus by simply rotating a disk.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view, and FIG. 2 is a plan view with the lid plate removed. DESCRIPTION OF SYMBOLS 1... Outer box, 4... Plate body, 5... Inert gas storage chamber, 6... Lid plate, 7... Upper processing chamber, 8... Lower processing chamber, 9... Recessed part, 10... Disc-shaped sample holder, 12... motor, 13... upper electrode plate,
14... Lower electrode plate, 16, 17... Gas supply pipe, 18... Inert gas supply pipe, 19, 20, 2
1... Exhaust pipe, 22, 23... Power supply circuit, 2
4, 25, 26...pressure sensor.

Claims (1)

[Claims] 1 In an apparatus for forming thin films using low-temperature plasma, a central A disk-shaped sample holder, which has a plurality of recesses for attaching samples on the front and back surfaces at positions approximately equidistant from each other, is rotatably inserted into a slit provided in the partition plate in advance, and is installed with an upright shaft support across the upper and lower processing chambers. At the same time, two pairs of electrode plates are provided upright so as to face each other at positions corresponding to the recessed portions in the upper and lower processing chambers, and furthermore, gas supply lines are provided on the circumferential surface of the outer box that communicate with the upper and lower processing chambers and the inert gas storage chamber. A multi-stage thin film forming apparatus using plasma, which is equipped with a pipe, an exhaust pipe, a power supply circuit connected to the upper and lower electrode plates, and a rotating mechanism for a disk-shaped sample holder.